1,057 results on '"Statistical hypothesis testing"'
Search Results
102. The Sensitivity of the Efficient Market Hypothesis to Alternative Specifications of the Market Model.
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BRENNER, MENACHEM
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EFFICIENT market theory ,STOCK splitting ,MATHEMATICAL models of finance ,CAPITAL assets pricing model ,EXPECTED returns ,STATISTICAL hypothesis testing ,MARKET equilibrium ,MATHEMATICAL models of investments ,PREDICTION models ,PARAMETER estimation - Abstract
The article focuses on market models that test the efficiency of capital markets and the efficient market hypothesis (EMH). A sampling of stock splits is used to test the accuracy of empirical research on market efficiency and compares the results to other models such as equilibrium models and one-factor market models, which relate to systematic risk. The experimental design of the stock splits model considers the residual and estimation periods around the split and the company behavior before and after the event. The capital asset pricing model is mentioned, as well as factors contributing to the validity of market predictions and tests for market efficiency.
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- 1979
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103. The Search for Information by Underwriters and Its Impact on Municipal Interest Cost.
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BENSON, EARL D.
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MUNICIPAL bonds ,INTEREST costs ,INFORMATION-seeking behavior ,BIDS ,MUNICIPAL bond insurance ,BOND prices ,STATISTICAL hypothesis testing ,BOND market ,PRICES - Abstract
The article discusses underwriter search for price information and its effect on the interest costs of new municipal bond issues. Aggregate underwriter search is measured by the intensity of the search, the number of bids received, the number of searchers, and an estimation of interest-rate dispersion. The basic model for testing the impact of searches on bond costs considers factors that affect issuer interest costs--such as market conditions and underwriter competition--and characteristics of the issue and issuer--such as default risk and type of bond. The research of economist Reuben Kessel, who studied two components of interest cost--underwriter planned spreads and reoffering yields--is mentioned.
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- 1979
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104. Equity Rights Issues and the Efficiency of the UK Stock Market.
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MARSH, PAUL
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EFFICIENT market theory ,PREDICTION models ,MARTINGALES (Mathematics) ,SUPPLY & demand ,STOCK prices ,FINANCIAL market reaction ,STATISTICAL hypothesis testing ,ELASTICITY (Economics) ,DEMAND function ,DATABASES - Abstract
This paper describes an empirical study of UK rights issues, involving various tests of semi-strong form market efficiency with respect to the announcement of rights issues. In addition, the Price Pressure Hypothesis, which asserts that equity issues, by increasing the supply of shares, temporarily depress the share price, is tested against the competing Substitution Hypothesis. Since this involves estimating the demand curve for a company's shares, our results provide evidence not only on market efficiency but also on market liquidity, and whether companies can raise new equity at existing market prices. The study is also of methodological interest in that it uses a number of alternative models for testing market efficiency, thus allowing us to test the sensitivity of our conclusions to the particular methodology employed. This is also one of the first studies to use the new London Share Price Database (LSPD), which is the first comprehensive source of UK share returns data to become available for research purposes. [ABSTRACT FROM AUTHOR]
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- 1979
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105. Testing for a Flat Spectrum on Efficient Market Price Data.
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PRAETZ, PETER D.
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COMMODITY futures ,MATHEMATICAL models of investments ,EXPECTED returns ,TIME series analysis ,STATISTICAL hypothesis testing ,EFFICIENT market theory - Abstract
The article defines procedures for determining if a series of estimated spectral ordinates has a flat spectrum, which is associated with independent random variables. The examples in applied statistics refer to commodity futures and securities prices. The discussion focuses on spectral analysis, correlation of estimated spectral ordinates, uncorrelated price changes, sampling fluctuations concerning estimated spectral ordinates, and the evaluation of tests for randomness. The Tukey-Hanning and Parzen weighting functions, the integrated periodogram Kolmorogov-Smirnov test, tau and sign change tests, the Melbourne Stock Exchange Share Price Indices, and a frequency domain capital offset pricing model are mentioned, as well as seasonality.
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- 1979
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106. Anti-Diversification or Optimal Programmes for Infrequently Revised Portfolios.
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GOLDMAN, M. BARRY
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MATHEMATICAL models of investments ,PORTFOLIO management (Investments) ,STATISTICAL weighting ,RISK aversion ,MATHEMATICAL optimization ,UTILITY functions ,STATISTICAL hypothesis testing ,CUSUM technique ,RANDOM walks ,ASYMPTOTIC theory in mathematical statistics - Abstract
Diversification is the central tenet of portfolio theory. However, casual empiricism and rigorous investigation (Friend and Blume) reveal the impotence of the diversification principle as a guide to the description of a representative agent's portfolio. Consequently, a re-examination of the traditional axiomatic systems of portfolio theory is in order so that we may discover the source of this theory-reality discrepancy. A full analysis of portfolio axiom systems is beyond the scope of this paper. Accordingly, we shall limit ourselves to a few observations about some popular axiom systems that motivate the subsequent analysis. I) Three behavioral postulates are often invoked to rationalize unexpected gambling behavior: 1) the agent is not ethically neutral—he enjoys the act of gambling, 2) the agent's utility function is not strictly concave in wealth—he is not strictly risk averse, and 3) the agent is stupid—he does not know how to optimize. We deplore these "explanations" since they are contrary to our desired description of markets—markets that are easily amenable to systematic analysis. Therefore, we reserve these postulates as residual excuses should the other explanations of the phenomenon raft us. II) Some abrogations of traditional assumptions could lead to less diversification—but show no systematic tendencies for the majority of agents to be almost totally undiversified. The existence of nonmarketable assets (Mayers) and heterogeneous expectations are of this class. III) Transaction and decision costs could potentially affect the optimal degree of diversification. A complete specification of how such costs affect portfolio choice is analytically intractable. However, a concomitant empirical fact—the existence of lengthy time periods between portfolio revisions for most investors—indicates a mode of simplified analysis that may capture the flavor of such costs in the portfolio problem. Suppose mo... [ABSTRACT FROM AUTHOR]
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- 1979
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107. INVESTMENT PERFORMANCE OF COMMON STOCKS IN RELATION TO THEIR PRICE-EARNINGS RATIOS: A TEST OF THE EFFICIENT MARKET HYPOTHESIS.
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BASU, S.
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EFFICIENT market theory ,PRICE-earnings ratio ,STOCK research (Finance) ,INVESTMENT analysis ,RATIO analysis ,RATE of return ,STOCK prices ,DIVIDEND yield ,INVESTMENTS ,STATISTICAL hypothesis testing - Abstract
In this paper an attempt was made to determine empirically the relationship between investment performance of equity securities and their P/E ratios. While the efficient market hypothesis denies the possibility of earning excess returns, the price-ratio hypothesis asserts that P/E ratios, due to exaggerated investor expectations, may be indicators of future investment performance. During the period April 1957-March 1971, the low P/E portfolios seem to have, on average, earned higher absolute and risk-adjusted rates of return than the high P/E securities. This is also generally true when bias on the performance measures resulting from the effect of risk is taken into account. These results suggest a violation in the joint hypothesis that (i) the asset pricing models employed in this paper have descriptive validity and (ii) security price behavior is consistent with the efficient market hypothesis. If (i) above is assumed to be true, conclusions pertaining to the second part of the joint hypothesis may be stated more definitively. We therefore assume that the asset pricing models are valid. The results reported in this paper are consistent with the view that P/E ratio information was not "fully reflected" in security prices in as rapid a manner as postulated by the semi-strong form of the efficient market hypothesis. Instead, it seems that disequilibria persisted in capital markets during the period studied. Securities trading at different multiples of earnings, on average, seem to have been inappropriately priced vis-a-vis one another, and opportunities for earning "abnormal'' returns were afforded to investors. Tax-exempt and tax-paying investors who entered the securities market with the aim of rebalancing their portfolios annually could have taken advantage of the market disequilibria by acquiring low P/E stocks. From the point of view of these investors a "market inefficiency" seems to have existed. On the other hand, transactions and search costs and t... [ABSTRACT FROM AUTHOR]
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- 1977
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108. Reproducibility, p‐values, and type III errors: response to Mayo (2022).
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STATISTICAL hypothesis testing , *SEQUENTIAL analysis , *DISTRIBUTION (Probability theory) , *CONFIRMATION bias , *FALSE positive error - Abstract
One reason a nominal I p i -value may not be a genuine I p i -value is that calculating I T i may involve many steps, including data selection, model selection, test selection, and selective reporting. Keywords: hypothesis tests; statistics EN hypothesis tests statistics 1 2 2 10/04/22 20221001 NES 221001 I enjoyed Professor Mayo's (2022) comment in I Conservation Biology i very much, and agree enthusiastically with most of it. In my opinion, the main problems with I p i -values are faulty interpretation, even of genuine I p i -values; use of nominal I p i -values that are not genuine I p i -values; and, perhaps most importantly, testing statistical hypotheses that have no connection to the scientific hypotheses. [Extracted from the article]
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- 2022
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109. An affordable apparatus for fine‐controlled emulation of buzzing frequencies of bees for the testing hypothesis in buzz interactions.
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Rodrigues, Ernani V., Riguette, Júlia R., Pereira, Henrique R. C., Tesch, Juliétty A., and Silva, Ary G.
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BEE behavior , *STATISTICAL hypothesis testing , *ANIMAL feeding behavior , *POLLINATION by bees , *PALYNOLOGY , *PLANT classification - Abstract
Abstract: The buzzing foraging behavior of female bees for pollen harvesting called the attention of early pollination biologists. Flower types that demand this buzzing behavior comprise about 20,000 species of different and phylogenetically unrelated plant taxa, suggesting that it had independently evolved many times among the flowering plants. Between the late 1970s and early 1980s, theoretical papers had modeled the energetics of buzz pollination, but, up to this moment, no hypothesis was experimentally tested concerning the theoretical basis of the energetics of buzz pollination. We present a cost‐effective and simple apparatus, including a digital and highly accurate frequency generator, and a device for the transference of buzz‐frequency energy to the receptive floral unity. The receptive floral unities may comprise the entire or partial androecium, or the tubular corolla, or, in some cases, the whole flower. This apparatus can be easily used in both laboratory and field conditions of research, as natural air currents are avoided, and the response of pollen liberation can be quantitatively measured by pollen grain counts that can be captured by adhesion in slide poured with an isosmotic lactate–glycerol media. The maximum displacement of the hardwire beam/claw system was 0.1170 ± 0.0006 mm @ 150 Hz; 0.021 ± 0.003 mm @ 250 Hz; 0.010 ± 0.001 mm @ 350 Hz; 0.0058 ± 0.0001 mm @ 450 Hz; and 0.0082 ± 0.0005 mm @ 550 Hz. Hypothesis contrasting frequency emission and pollen liberation measured as pollen grain counts may be tested in a species flower type by simple linear regression if pollen counts are normally distributed, or ordinal logistic regression, with non‐normal counts. The comparison among different flower‐type requirements can be tested through appropriate statistical methods for both normally and non‐normally distributed pollen grain counts. [ABSTRACT FROM AUTHOR]
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- 2018
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110. Full covariate modelling approach in population pharmacokinetics: understanding the underlying hypothesis tests and implications of multiplicity.
- Author
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Xu, Xu Steven, Yuan, Min, Zhu, Hao, Yang, Yaning, Wang, Hui, Zhou, Honghui, Xu, Jinfeng, Zhang, Liping, and Pinheiro, Jose
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PHARMACOKINETICS , *STATISTICAL hypothesis testing , *CLINICAL trials , *DECISION making , *MULTIPLICITY (Mathematics) - Abstract
Aims: To clarify the hypothesis tests associated with the full covariate modelling (FCM) approach in population pharmacokinetic analysis, investigate the potential impact of multiplicity in population pharmacokinetic analysis, and evaluate simultaneous confidence intervals (SCI) as an approach to control multiplicity. Methods: Clinical trial simulations were performed using a simple one‐compartment pharmacokinetic model. Different numbers of covariates, sample sizes, effect sizes of covariates, and correlations among covariates were explored. The false positive rate (FPR) and power were evaluated. Results: The FPR for the FCM approach dramatically increases with number of covariates. The chance of incorrectly selecting ≥1 seemingly clinically relevant covariates can be increased from 5% to a 40–70% range for 10–20 covariates. The SCI approach may provide appropriate control of the family‐wise FPR, allowing more appropriate decision making. As a result, the power detecting real effects without incorrectly identifying non‐existing effects can be greatly improved by the SCI approach compared to the approach in current practice. The performance of the SCI approach is driven by the ratio of sample size to number of covariates. The FPR can be controlled at 5% and 10% using the SCI approach when the ratio was ≥20 and 10, respectively. Conclusion: The FCM approach still lies within the framework of statistical testing, and therefore multiplicity is an issue for this approach. It is imperative to consider multiplicity reporting and adjustments in FCM modelling practice to ensure more appropriate decision making. [ABSTRACT FROM AUTHOR]
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- 2018
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111. Pop‐Inference: An educational application to evaluate statistical differences among populations.
- Author
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Arrontes, Julio
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STATISTICAL hypothesis testing , *DEMOGRAPHIC databases , *RANDOMIZATION (Statistics) , *NULL hypothesis , *STATISTICAL bootstrapping - Abstract
Abstract: Pop‐Inference is an educational tool designed to help teaching of hypothesis testing using populations. The application allows for the statistical comparison of demographic parameters among populations. Input demographic data are projection matrices or raw demographic data. Randomization tests are used to compare populations. The tests evaluate the hypothesis that demographic parameters differ among groups of individuals more that should be expected from random allocation of individuals to populations. Confidence intervals for demographic parameters are obtained using the bootstrap. Tests may be global or pairwise. In addition to tests on differences, one‐way life table response experiments (LTRE) are available for random and fixed factors. Planned (a priori) comparisons are possible. Power of comparison tests is evaluated by constructing the distribution of the test statistic when the null hypothesis is true and when it is false. The relationship between power and sample size is explored by evaluating differences among populations at increasing population sizes, while keeping vital rates constant. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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112. What is the actual prevalence of migraine?
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Yeh, Wei Z., Blizzard, Leigh, and Taylor, Bruce V.
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MIGRAINE , *DISEASE prevalence , *BIOMARKERS , *EPIDEMIOLOGY , *STATISTICAL hypothesis testing - Abstract
Abstract: Objectives: Population prevalence studies of migraine report prevalence rates of between 2.6 and 21.7%, with an average of ~12%. However, migraine prevalence among neurologists is reported to be significantly higher, between 27.6% and 48.6%. Increasing knowledge of the protean manifestations of migraine may explain this difference. Similarly, under‐recognition of migraine in control groups may explain the lack of genetic and biomarker findings in this disorder. We therefore sought to determine the prevalence of migraine in an admixed group of individuals with varied knowledge of migraine symptomatology. Methods: Attendees at the Australian and New Zealand Association of Neurologists Annual Scientific Meeting (ANZAN ASM) 2017 were surveyed anonymously. Those surveyed included three groups: neurologists, neurology trainees, and others including nonclinical researchers, members of lay organizations, and representatives of the pharmaceutical industry. Results: In total, 313 of 606 attendees responded (51.7%). 65.9% of neurologist, 57.4% of trainee, and 52.5% of others respondents had a personal history of migraine, with the difference between neurologists and others being statistically significant (p = .03). Migraine in migraineurs and nonmigraine headache in nonmigraineurs were nearly all self‐diagnosed. Among neurologist migraineurs, 51.2% experienced migraine with aura and 43% migraine without aura. Conclusions: Migraine prevalence is significantly higher in neurologists compared to non‐neurologists and at least 2–3 times higher than reported in population prevalence studies. This may be due to significant under‐recognition of migraine in non‐neurologists. This under‐recognition of migraine may significantly influence the search for genetic predictors and biomarkers of migraine. [ABSTRACT FROM AUTHOR]
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- 2018
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113. Extracting statistically significant behaviour from fish tracking data with and without large dataset cleaning.
- Author
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Beyan, Cigdem, Katsageorgiou, Vasiliki-Maria, and Fisher, Robert B.
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STATISTICAL hypothesis testing , *DATA extraction , *COMPUTER vision , *DATA binning , *ESTIMATION theory - Abstract
Extracting a statistically significant result from video of natural phenomenon can be difficult for two reasons: (i) there can be considerable natural variation in the observed behaviour and (ii) computer vision algorithms applied to natural phenomena may not perform correctly on a significant number of samples. This study presents one approach to clean a large noisy visual tracking dataset to allow extracting statistically sound results from the image data. In particular, analyses of 3.6 million underwater trajectories of a fish with the water temperature at the time of acquisition are presented. Although there are many false detections and incorrect trajectory assignments, by a combination of data binning and robust estimation methods, reliable evidence for an increase in fish speed as water temperature increases are demonstrated. Then, a method for data cleaning which removes outliers arising from false detections and incorrect trajectory assignments using a deep learning-based clustering algorithm is proposed. The corresponding results show a rise in fish speed as temperature goes up. Several statistical tests applied to both cleaned and not-cleaned data confirm that both results are statistically significant and show an increasing trend. However, the latter approach also generates a cleaner dataset suitable for other analysis. [ABSTRACT FROM AUTHOR]
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- 2018
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114. Is reappraisal always effective in modifying emotional reactions in females? The role of regulatory timing and goals.
- Author
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Yan, Chunping, Lin, Na, Cui, Lixia, and Zhang, Qin
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EMOTIONS , *GOAL (Psychology) , *EVOKED potentials (Electrophysiology) , *COGNITIVE ability , *STATISTICAL hypothesis testing - Abstract
Abstract: Introduction: Numerous studies have explored the effect of cognitive reappraisal before or after emotion‐inducing events. However, only a few studies have examined the influence of regulatory timing on the effectiveness of reappraisal. Thus, the aim of this study was to investigate the role of regulatory timing and goals in reappraisal regulation, which would help promote the specific application of cognitive reappraisal in emotion regulation. We hypothesized that decrease reappraisal would be more effective when initiated early rather than late, but increase reappraisal would be more effective when initiated in the emotional high‐activation phase. Methods: This study, via event‐related potential (ERP) technique, probed the influence of the timing and regulatory goal on negative emotion when reappraisal was introduced, respectively 500 ms before (anticipatory), 2,000 ms after (online 2,000 ms) picture onset (in Experiment 1), 500 ms after (online 500 ms) picture onset, and 1,500 ms after (online 1,500 ms) picture onset (in Experiment 2). Results: Based on the ERP results, under the anticipatory regulation condition, the LPP amplitude in the parietal area was significantly reduced by decrease reappraisal during 700–2,100 ms after picture onset, and under the online 500 ms regulation condition, the LPP in central and parietal areas was significantly enhanced by increase reappraisal during 450–750 ms after regulatory cue onset. Moreover, our results showed that increase reappraisal evoked a larger prefrontal or frontal LPP than decrease reappraisal beginning at about 700 ms after picture onset under the anticipatory regulation condition and beginning at 450 ms after regulatory cue onset under the online 500 ms regulation condition, which may reflect increased cognitive effort and mental conflict associated with increase reappraisal. Conclusion: The anticipatory reappraisal successfully decreased negative emotion, and online 500 ms reappraisal successfully increased negative emotion. Our results support the hypothesis. [ABSTRACT FROM AUTHOR]
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- 2018
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115. Integrating nutrition into health systems at community level: Impact evaluation of the community‐based maternal and neonatal health and nutrition projects in Ethiopia, Kenya, and Senegal.
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Kung'u, Jacqueline K., Pendame, Richard, Ndiaye, Mame Bineta, Gerbaba, Mulusew, Ochola, Sophie, Faye, Adama, Basnet, Sulochana, Frongillo, Edward A., Wuehler, Sara, and De‐Regil, Luz Maria
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BREASTFEEDING , *DELIVERY (Obstetrics) , *DIETARY supplements , *FOLIC acid , *HEALTH promotion , *IRON compounds , *LONGITUDINAL method , *RESEARCH methodology , *NUTRITION , *POSTNATAL care , *PRENATAL care , *PROBABILITY theory , *RESEARCH funding , *STATISTICAL sampling , *STATISTICAL hypothesis testing , *LOGISTIC regression analysis , *JUDGMENT sampling , *STATISTICAL power analysis , *STATISTICAL significance , *EFFECT sizes (Statistics) , *CROSS-sectional method , *EVALUATION of human services programs , *DESCRIPTIVE statistics , *ODDS ratio , *CLUSTER sampling - Abstract
Abstract: Maternal undernutrition and mortality remain high in several African countries. Key nutrition and health interventions improve maternal and birth outcomes. Evidence is scarce on how to strengthen health systems to ensure pregnant women and newborns are reached with these interventions. We conducted three quasi‐experimental nonrandomized Community Based Maternal and Neonatal Health and Nutrition projects in regions of Ethiopia, Senegal, and Kenya to demonstrate how proven nutrition interventions could be integrated into health programs to improve knowledge and practices during pregnancy, birth, and postpartum. We evaluated impact on knowledge and practices related to maternal and neonatal care using logistic regression and repeated‐measures models with districts as a fixed variable and adjusted for covariates. Combined country analyses show significant positive effects of the intervention on women receiving first antenatal care visit (ANC) during first trimester (OR = 1.44;
p < .001), those consuming any iron and folic acid supplement during their latest pregnancy (OR = 1.60;p = .005), those whose <6 months infants were exclusively breastfed (OR = 2.01;p =.003), those whose delivery was facility based (OR = 1.48;p =.031), and those whose postnatal care was facility based (OR = 2.15;p <.001). There was no significant differences between intervention and control groups regarding one or more and four or more ANC visits, women consuming iron and folic acid for ≥90 days, and early initiation of breastfeeding. We conclude that integrating proven nutrition interventions into health programs at community level improved components of access to and use of ANC, delivery services, and postnatal care by women in three African countries. [ABSTRACT FROM AUTHOR]- Published
- 2018
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116. Consumption of obesogenic foods in non-Hispanic black mother-infant dyads.
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Kay, Melissa C., Wasser, Heather, Adair, Linda S., Bentley, Margaret E., Thompson, Amanda L., Siega-Riz, Anna Maria, and Suchindran, Chirayath M.
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RISK of childhood obesity , *OBESITY risk factors , *BEVERAGES , *BLACK people , *DIET , *FOOD relief , *LONGITUDINAL method , *MOTHERS , *NUTRITIONAL assessment , *POVERTY , *PROBABILITY theory , *SNACK foods , *STATISTICAL hypothesis testing , *LOGISTIC regression analysis , *DATA analysis software , *DESCRIPTIVE statistics , *DIETARY sucrose - Abstract
Obesity continues to be a problem in the United States. Of particular concern is the epidemic of early childhood obesity. A significant predictor of child diet is maternal diet, but little is known about this relationship during infancy. This study examined the association between maternal and infant consumption of key food groups from 6 to 18 months using data from the Infant Care, Feeding, and Risk of Obesity Study, a prospective cohort of 217 non-Hispanic black, low-income, first-time mothers. Using data from 24-hr dietary recalls collected during in-home visits at 6, 9, 12, and 18 months, we assessed longitudinal associations between mother and child intake of both energy-dense, nutrient-poor (obesogenic) food groups and fibre-, nutrient-rich food groups using random intercept logistic regression. Both mothers and their infants had high intake of sugar-sweetened beverages, desserts, and sweets and low intake of vegetables and whole grains. Infant consumption of key food groups was strongly associated with maternal consumption, suggesting the need for focused interventions to target maternal diet as a pathway to decreasing risk for the establishment of poor dietary patterns early in life. [ABSTRACT FROM AUTHOR]
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- 2018
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117. Associations between social support, psychological well-being, decision making, empowerment, infant and young child feeding, and nutritional status in Ugandan children ages 0 to 24 months.
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Ickes, Scott B., Mandel, Maia P., Roberts, Alison C., and Wu, Michael
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ARTIFICIAL feeding , *BABY foods , *CONFIDENCE intervals , *STATISTICAL correlation , *DECISION making , *FACTOR analysis , *HUMAN growth , *MOTHERS , *MULTIVARIATE analysis , *PROBABILITY theory , *QUESTIONNAIRES , *REGRESSION analysis , *RESEARCH funding , *SCALE analysis (Psychology) , *SELF-efficacy , *STATISTICAL hypothesis testing , *LOGISTIC regression analysis , *STATISTICAL power analysis , *SOCIAL support , *STATISTICAL significance , *WELL-being , *DATA analysis software , *NUTRITIONAL value , *DESCRIPTIVE statistics , *NUTRITIONAL status , *ODDS ratio - Abstract
Maternal capabilities-qualities of mothers that enable them to leverage skills and resources into child health-hold potential influence over mother's adoption of child caring practices, including infant and young child feeding. We developed a survey ( n = 195) that assessed the associations of 4 dimensions of maternal capabilities (social support, psychological health, decision making, and empowerment) with mothers' infant and young child feeding practices and children's nutritional status in Uganda. Maternal responses were converted to categorical subscales and an overall index. Scale reliability coefficients were moderate to strong (α range = 0.49 to 0.80). Mothers with higher social support scores were more likely to feed children according to the minimum meal frequency (odds ratio [OR] [95% confidence interval (CI)] = 1.38 [1.10, 1.73]), dietary diversity (OR [95% CI] = 1.56 [1.15, 2.11]), iron rich foods, (OR [95% CI] = 1.47 [1.14, 1.89]), and minimally acceptable diet (OR [95% CI] = 1.55 [1.10, 2.21]) indicators. Empowerment was associated with a greater likelihood of feeding a minimally diverse and acceptable diet. The maternal capabilities index was significantly associated with feeding the minimum number of times per day (OR [95% CI] = 1.29 [1.03, 1.63]), dietary diversity (OR [95% CI] = 1.44 [1.06, 1.94]), and minimally acceptable diet (OR [95% CI] = 1.43 [1.01, 2.01]). Mothers with higher psychological satisfaction were more likely to have a stunted child (OR [95% CI] = 1.31 [1.06, 1.63]). No other associations between the capabilities scales and child growth were significant. Strengthening social support for mothers and expanding overall maternal capabilities hold potential for addressing important underlying determinants of child feeding in the Ugandan context. [ABSTRACT FROM AUTHOR]
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- 2018
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118. Premastication and length for age among children under 24 months in Laos.
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Conkle, Joel, Kounnavong, Sengchanh, Young, Melissa, and Stein, Aryeh D.
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BREASTFEEDING , *CONFIDENCE intervals , *INFANT nutrition , *MOTHERS , *PROBABILITY theory , *REGRESSION analysis , *RESEARCH funding , *STATISTICAL hypothesis testing , *STATURE , *SURVEYS , *T-test (Statistics) , *CROSS-sectional method , *DATA analysis software , *DESCRIPTIVE statistics , *ODDS ratio - Abstract
Premastication of infant food by caregivers is common in Laos. Premastication is hypothesized to have both positive and negative implications for children, but the net effect of premastication on child health and nutrition is largely unknown because of a lack of research. This study quantitatively describes premastication in 5 provinces of Laos and examines the associations between premastication and the length of young children. We analyzed cross-sectional data from the Laos 2015 Food and Nutrition Security Survey to characterize premastication among children under 2 years of age ( n = 1,661) and to test associations between premastication and child length-for-age z-score. We explored associations using multilevel mixed effects linear regression. Among children 0-23 months, 27.2% of mothers reported giving premasticated food in the past week. Receipt of premasticated food was inversely associated with length-for-age z-score after controlling for potential confounders (child's age, ethno-linguistic group, wealth, and parity) among children 6-13 months (β −0.36, CI [−0.68, −0.04]) and among children 14-23 months (β −0.43, CI [−0.81, −0.05]). For breastfed children 0-5 months who received complementary food, the coefficient was similar, but the association was not statistically significant (β −0.42, CI [−1.2, 0.37]). Premastication is a common feeding practice for children 0-23 months of age, and many infants consume premasticated food on a daily basis. There was a negative relationship between premastication and child length. However, given the cross-sectional nature of this study and potential unmeasured confounding factors, reverse causality or confounding cannot be ruled out. Longitudinal studies are needed to develop recommendations on premastication. [ABSTRACT FROM AUTHOR]
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- 2018
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119. Suboptimal maternal and cord plasma pyridoxal 5′ phosphate concentrations are uncommon in a cohort of Canadian pregnant women and newborn infants.
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Plumptre, Lesley, Masih, Shannon P., Kim, Denise, Visentin, Carly E., Kim, Young-In, O'Connor, Deborah L., Sohn, Kyoung-Jin, Ly, Anna, Berger, Howard, and Croxford, Ruth
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CONFIDENCE intervals , *STATISTICAL correlation , *DIETARY supplements , *CORD blood , *GENETIC polymorphisms , *NUTRITIONAL assessment , *PROBABILITY theory , *QUESTIONNAIRES , *REGRESSION analysis , *RESEARCH funding , *STATISTICAL sampling , *STATISTICAL hypothesis testing , *STATISTICS , *T-test (Statistics) , *VITAMIN B6 , *HOMOCYSTEINE , *STATISTICAL power analysis , *DATA analysis , *DATA analysis software , *DESCRIPTIVE statistics , *PREGNANCY - Abstract
Vitamin B6 is important in fetal development, but little is known of the vitamin B6 status of pregnant women and newborns in North America and potential modifying factors. This prospective study determined maternal and cord plasma concentrations of pyridoxal 5′ phosphate (PLP; an indicator of vitamin B6 status) in a convenience sample of 368 Canadian pregnant women and their newborns. The association of maternal intake of vitamin B6 and fetal genetic variants with cord plasma PLP and homocysteine concentrations was also examined. Dietary and supplemental intakes of vitamin B6 were assessed in early and mid to late pregnancy. PLP concentrations were measured in maternal plasma in early pregnancy and at delivery, and in cord plasma. Six fetal variants of the MTHFR and CβS genes were assessed for their association with cord plasma PLP and homocysteine concentrations. Geometric mean (95% CI) PLP concentrations were 107 (98, 116) nmol/L in early pregnancy and 58 (53, 62) nmol/L at delivery, respectively, and 296 (275, 319) nmol/L in cord blood ( p < .0001). During early pregnancy and at delivery, 3.6% and 5.5% of women had plasma PLP concentrations <20 nmol/L, respectively. Ninety eight percent of the women with supplemental B6 intake of at least the recommended dietary allowance had PLP concentrations >20 nmol/L. Fetal genetic variants were not associated with cord PLP and homocysteine concentrations. Vitamin B6 deficiency is uncommon in a cohort of Canadian pregnant women due largely to prevalent vitamin B6 supplement use. [ABSTRACT FROM AUTHOR]
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- 2018
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120. Higher maternal vitamin D concentrations are associated with longer leukocyte telomeres in newborns.
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Kim, Jung-Ha, Kim, Gwang Jun, Lee, Donghee, Ko, Jae-Hong, Lim, Inja, Bang, Hyoweon, Koes, Bart W., Seong, Byeongchan, and Lee, Duk-Chul
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LEUCOCYTES , *TELOMERES , *BIRTH weight , *STATISTICAL correlation , *GOODNESS-of-fit tests , *INGESTION , *INTERVIEWING , *NUTRITIONAL assessment , *PROBABILITY theory , *QUESTIONNAIRES , *REGRESSION analysis , *RESEARCH funding , *STATISTICAL hypothesis testing , *T-test (Statistics) , *VITAMIN D , *STATISTICAL power analysis , *MULTIPLE regression analysis , *EFFECT sizes (Statistics) , *CROSS-sectional method , *DATA analysis software , *DESCRIPTIVE statistics , *CHILDREN , *PREGNANCY , *PHYSIOLOGY - Abstract
Gestational vitamin D insufficiency is related with increased risks of various diseases and poor health outcomes later in life. Telomere length at birth or early in life is known to be a predictor of individual health. Both vitamin D and telomere length are related with various health conditions, and vitamin D concentrations are associated with leukocyte telomere lengths in women. We investigated the association between maternal vitamin D concentrations and newborn leukocyte telomere lengths. This cross-sectional study included 106 healthy pregnant women without adverse obstetric outcomes and their offspring. We examined the maternal age, weight before pregnancy, health behaviours, and nutritional intakes, along with each newborn's sex and birthweight, and we measured maternal height, telomere length, total white blood cell count, and glycosylated haemoglobin as covariates. Pearson's correlation coefficients were calculated to evaluate the relationship between the baseline variables and newborn leukocyte telomere lengths. To confirm that there was an independent association between newborn leukocyte telomere lengths and maternal vitamin D concentrations, we performed a stepwise multiple linear regression analysis. Newborn leukocyte telomere lengths correlated positively with maternal leukocyte telomere lengths ( r = .76, p < .01), maternal 25-hydroxyvitamin D concentrations ( r = .72, p < .01), maternal energy intakes ( r = .22, p = .03), and newborn body weights ( r = .51, p < .01). In the multivariate model, newborn leukocyte telomere lengths were associated with maternal vitamin D concentrations (β = .33, p < .01). These findings suggest that the maternal vitamin D concentration during pregnancy may be a significant determinant of the offspring's telomere length. [ABSTRACT FROM AUTHOR]
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- 2018
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121. Predicting children's fussiness with vegetables: The role of feeding practices.
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Holley, Clare E., Haycraft, Emma, and Farrow, Claire
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AGE distribution , *ARTIFICIAL feeding , *CAREGIVERS , *COOKING , *FOOD habits , *FORECASTING , *INGESTION , *MOTHERS , *MOTIVATION (Psychology) , *NUTRITIONAL assessment , *PROBABILITY theory , *QUESTIONNAIRES , *REGRESSION analysis , *REWARD (Psychology) , *STATISTICAL hypothesis testing , *STATISTICS , *VEGETABLES , *STATISTICAL power analysis , *DATA analysis , *STATISTICAL significance , *DESCRIPTIVE statistics , *MANN Whitney U Test - Abstract
Vegetables are commonly rejected by children, making it is important to consider factors that are associated with children's fussiness with vegetables. The current study aimed to investigate whether fussiness with vegetables is associated with a number of factors including caregiver and child vegetable consumption; caregivers' general feeding practices; and caregivers' vegetable-specific feeding practices. Caregivers ( N = 297) of preschool children completed questionnaire measures of their child's fussiness with vegetables, as well as several caregiver and child factors hypothesised to be associated with children's fussiness with vegetables. Findings indicate that children who are fussier with vegetables consume a smaller quantity of vegetables and that almost all have caregivers who eat a smaller quantity of vegetables. Children's fussiness with vegetables was not significantly related to any general feeding practices used by caregivers. However, children's fussiness with vegetables was significantly associated with the use of several vegetable specific feeding practices. Caregivers of fussier children used more encouragement/pressure to eat with vegetables ( r = 0.14, p = .01), hid vegetables within other foods more often ( r = 0.30, p = <.01), used more food rewards for vegetable consumption ( r = 0.19, p <.01), more other rewards for vegetable consumption ( r = 0.21, p < .01), and compromised more when feeding vegetables ( r = 0.14, p = .01). These findings suggest that rather than caregivers' general feeding practices being related to children's fussiness with vegetables, the specific feeding practices used when vegetables are rejected are more significant. It may therefore be helpful to develop advice for caregivers about which feeding practices to avoid when faced with a child who is fussy about eating vegetables. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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122. Simulated effects of home fortification of complementary foods with micronutrient powders on risk of inadequate and excessive intakes in West Gojjam, Ethiopia.
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Abebe, Zeweter, Baye, Kaleab, and Haki, Gulelat Desse
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NUTRITION disorders in infants , *ENRICHED foods , *BABY foods , *BREASTFEEDING , *CALCIUM , *CHILD development deviations , *COMPUTER simulation , *CONFIDENCE intervals , *GROWTH disorders , *INFANTS , *INFANT development , *INGESTION , *IRON , *IRON in the body , *NUTRITIONAL assessment , *NUTRITIONAL requirements , *PROBABILITY theory , *RESEARCH funding , *STATISTICAL hypothesis testing , *MICRONUTRIENTS , *ZINC , *STATISTICAL power analysis , *CROSS-sectional method , *DATA analysis software , *DESCRIPTIVE statistics , *MANN Whitney U Test , *DISEASE risk factors - Abstract
Home fortification of complementary foods (CFs) with multiple micronutrient powders (MNPs) is being scaled up in various countries, but little is known about the prevailing complementary feeding practices and the type and nutrient gaps to be filled with MNPs. The present study evaluated the complementary feeding practices of young children and simulated the risk of inadequate and excessive intakes associated with home fortification with MNPs. We have assessed the sociodemographic status, anthropometry, and complementary feeding practices of young children ( N = 122) in Mecha district, rural Ethiopia. Using a 2-day, quantitative 24-hr recall, usual intakes of energy, protein, iron, zinc, and calcium were estimated. The risks of inadequate and excessive iron and zinc intakes with or without home fortification scenarios were assessed. The simulations considered intakes from CFs assuming average breast milk contributions and additional nutrients provided by the MNPs. Stunting was highly prevalent (50%) and was associated with a lower dietary diversity ( P = .009) and nutrient intakes from the CFs. Median energy, zinc, and calcium intakes were below the estimated needs from CFs; protein needs were met. Median dietary iron intake appeared adequate, but 76%, 95% CI [68%, 84%], of children had inadequate intake (assuming low bioavailability), whereas another 8%, 95% CI: [3%, 13%], had excessive intakes. Simulation of daily and alternative day's fortification with MNP decreased the prevalence of inadequate iron and zinc intake but significantly increased the risk of excessive intakes that remained unacceptably high for iron (>2.5%). Untargeted MNP interventions may lead to excessive intakes, even in settings where poor complementary feeding practices are prevalent. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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123. Tracing dynamic linkages and spillover effect between Pakistani and leading foreign stock markets.
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Ghouse, Ghulam and Khan, Saud Ahmed
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EXTERNALITIES ,STOCK exchanges ,MARKET volatility ,STATISTICAL hypothesis testing ,GLOBAL Financial Crisis, 2008-2009 - Abstract
This study traces the degree of integration and volatility spillover effect between the Pakistani and leading foreign stock markets by analyzing the Meteor shower hypothesis. Daily data are used from nine worldly equity markets (KSE 100, NIKKEI 225, HIS, S&P 500, NASDAQ 100, DOW JONES, GADXI, FTSE 350 and DFMGI) for the period of 2005 to 2014. First, we used the whole data set and after that we split data set into two subsets, First subset of data contains the era of global financial crisis of 2008 from 2005 to 2009 and Second subset is after global financial crisis time period from 2010 to 2014 (The global crisis prevailed till end of 2009). By following the Hamao et al. (1990) technique the univariate GARCH type models are employed to explore the dynamic linkages between Pakistani and leading foreign stock markets. The results from whole data set illustrate that there is mixed co-movements between leading foreign stock markets and Pakistani stock market. The results from both subsets provide an evidence that there is a unidirectional mean and volatility spillover effect from S&P 500, NASDAQ 100, DJI and DFMGI to KSE 100. Also we found bidirectional spillover effect between DFMGI and KSE 100 from both subsets of data. We concluded that there is only one indirect linkage through which may the information transmitted to KSE 100. This linkage is developed due to the co-movement among KSE 100, DFMGI and NASDAQ 100 in crisis period. This integration between these markets may provide a sign of indirect linkage. It also exhibits the volatility in Pakistan stock market returns is instigated through direct effects as well as indirect effects. Our study brings important conclusions for financial institutions, portfolio managers, market players and academician to diagnose the nature and level of linkages between the financial markets. [ABSTRACT FROM AUTHOR]
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- 2017
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124. Nutrient composition of premixed and packaged complementary foods for sale in low- and middle-income countries: Lack of standards threatens infant growth.
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Masters, William A., Nene, Marc D., and Bell, Winnie
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BABY foods , *COMPARATIVE studies , *ELEMENTAL diet , *FOOD chemistry , *FAT content of food , *FOOD labeling , *INFANTS , *IRON , *NUTRITIONAL requirements , *PROBABILITY theory , *DIETARY proteins , *RESEARCH funding , *STATISTICAL hypothesis testing , *T-test (Statistics) , *ZINC , *NUTRITIONAL value , *DESCRIPTIVE statistics , *NUTRIENT density ,DEVELOPING countries - Abstract
Premixed flours for infant porridge are increasingly produced and sold in developing countries to complement continued breastfeeding. Such complementary food (CF) products have known efficacy against malnutrition in children from 6 to 24 months of age, but ingredient ratios and production processes may vary. This study provides the first systematic measurement of their actual nutrient composition. We purchased samples of 108 premixed CF products in 22 low- and middle-income countries, and commissioned blind laboratory measurement of each product's macronutrients and micronutrients. We compared measured contents to nutrient claims on their packaging and to CF standards from the Codex Alimentarius, the Super Cereal Plus product used in nutrition assistance programs, and the Lutter and Dewey (2003) recommendations, as well as our own modeled nutrient requirements for a healthy breastfed child. Actual densities are significantly different from nutrient claims for protein ( p = .013) and fat ( p = .000). Only 15% of samples met two of the three benchmarks for fat, 32% met the most stringent protein standard, while only 22% met them for iron, and 21% for zinc. The median healthy child consuming breast milk plus enough of these solid foods to meet energy needs would experience deficits of zinc at 6 months, iron at 6 and 9 months, and dietary fat from 12 months of age. In summary, premixed CF products can provide adequate nutrient density but usually do not, revealing the need and opportunity for independent monitoring and quality assurance to help grain millers making premixed foods maintain uniform ingredient ratios and production practices. [ABSTRACT FROM AUTHOR]
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- 2017
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125. Effects of Teriparatide on Joint Erosions in Rheumatoid Arthritis: A Randomized Controlled Trial.
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Solomon, D. H., Kay, J., Duryea, J., Lu, B., Bolster, M. B., Yood, R. A., Han, R., Ball, S., Coleman, C., Lo, E., Wohlfahrt, A., Sury, M., Yin, M., Yu, Z., Zak, A., and Gravallese, E. M.
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TERIPARATIDE , *CLINICAL trials , *COMPUTED tomography , *HAND , *JOINTS (Anatomy) , *LONGITUDINAL method , *PROBABILITY theory , *RHEUMATOID arthritis , *STATISTICAL sampling , *STATISTICAL hypothesis testing , *TUMOR necrosis factors , *WRIST , *BONE density , *RANDOMIZED controlled trials , *BLIND experiment , *CHEMICAL inhibitors , *THERAPEUTICS ,PREVENTION of disease progression - Abstract
Objective Articular erosions correlate with disability in rheumatoid arthritis (RA). Biologic agents reduce erosion progression in RA, but erosion healing occurs infrequently. This study was undertaken to assess the effects of the anabolic agent teriparatide on joint erosion volume in RA patients treated with a tumor necrosis factor inhibitor (TNFi). Methods We conducted a randomized controlled trial in 24 patients with erosive RA, osteopenia, and disease activity controlled by TNFi treatment for at least 3 months. Half were randomized to receive teriparatide for 1 year and the others constituted a wait-list control group. Subjects and primary rheumatologists were not blinded with regard to treatment assignment, but all outcomes were assessed in a blinded manner. The primary outcome measure was change in erosion volume determined by computed tomography at 6 anatomic sites. Significance within each hand and anatomic site was based on a 2-tailed test, with P values less than 0.05 considered significant. Results Baseline characteristics of the treatment groups were well balanced. After 52 weeks, the median change in erosion volume in the teriparatide group was −0.4 mm3 (interquartile range [IQR] −34.5, 29.6) and did not differ significantly from that in controls (median change +9.1 mm3 [IQR −29.6, 26.4]) ( P = 0.28). No significant difference in change in erosion volume was noted at the radius, ulna, or metacarpophalangeal joints. Bone mineral density improved at the femoral neck and lumbar spine in the teriparatide group. Conclusion Our findings indicate that teriparatide treatment for 1 year does not significantly reduce erosion volume in the hands or wrists of patients with established RA with disease activity controlled by TNFi treatment. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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126. The double edge to parasite escape: invasive host is less infected but more infectable.
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Keogh, Carolyn L., Miura, Osamu, Nishimura, Tomohiro, and Byers, James E.
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BIOLOGICAL invasions , *ECOSYSTEMS , *STATISTICAL hypothesis testing , *PARASITES , *BIOLOGICAL classification , *REPRODUCTION ,PARASITE evolution - Abstract
Nonnative species that escape their native-range parasites may benefit not only from reduced infection pathology, but also from relaxed selection on costly immune defenses, promoting reallocation of resources toward growth or reproduction. However, benefits accruing from a reduction in defense could come at the cost of increased infection susceptibility. We conducted common garden studies of the shore crab Hemigrapsus sanguineus from highly parasitized native (Japan) populations and largely parasite-free invasive (USA) populations to test for differences in susceptibility to infection by native-range rhizocephalan parasites, and to explore differences in host resource allocation. Nonnative individuals showed at least 1.8 times greater susceptibility to infection than their native counterparts, and had reduced standing metabolic rates, suggesting that less of their energy was spent on physiological self-maintenance. Our results support an indirect advantage to parasite escape via the relaxation of costly physiological defenses. However, this advantage comes at the cost of heightened susceptibility, a trade-off of parasite escape that is seldom considered. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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127. Bayesian power equivalence in latent growth curve models
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Timo von Oertzen, Angelika Stefan, and Psychologische Methodenleer (Psychologie, FMG)
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Statistics and Probability ,Bayesian probability ,power analysis ,structural equation modelling ,01 natural sciences ,Structural equation modeling ,010104 statistics & probability ,0504 sociology ,Arts and Humanities (miscellaneous) ,Frequentist inference ,Econometrics ,Humans ,Computer Simulation ,Longitudinal Studies ,0101 mathematics ,Equivalence (measure theory) ,General Psychology ,Statistical hypothesis testing ,Likelihood Functions ,Models, Statistical ,05 social sciences ,050401 social sciences methods ,Bayes factor ,Bayes Theorem ,General Medicine ,Original Articles ,sample size ,Power analysis ,Sample size determination ,Linear Models ,Original Article ,design analysis ,Factor Analysis, Statistical ,Mindfulness - Abstract
Longitudinal studies are the gold standard for research on time‐dependent phenomena in the social sciences. However, they often entail high costs due to multiple measurement occasions and a long overall study duration. It is therefore useful to optimize these design factors while maintaining a high informativeness of the design. Von Oertzen and Brandmaier (2013, Psychology and Aging, 28, 414) applied power equivalence to show that Latent Growth Curve Models (LGCMs) with different design factors can have the same power for likelihood‐ratio tests on the latent structure. In this paper, we show that the notion of power equivalence can be extended to Bayesian hypothesis tests of the latent structure constants. Specifically, we show that the results of a Bayes factor design analysis (BFDA; Schönbrodt & Wagenmakers (2018, Psychonomic Bulletin and Review, 25, 128) of two power equivalent LGCMs are equivalent. This will be useful for researchers who aim to plan for compelling evidence instead of frequentist power and provides a contribution towards more efficient procedures for BFDA.
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- 2020
128. Neighbour regions as the source of new industries.
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Boschma, Ron, Martín, Víctor, and Minondo, Asier
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DIVERSIFICATION in industry , *INDUSTRIALIZATION , *EXTERNALITIES , *STATISTICAL hypothesis testing , *EXPORTS - Abstract
The development of new industries demands access to local capabilities. Little attention has yet been paid to the role of spillovers from neighbour regions for industrial diversification, nor has the role of network linkages between neighbour regions been investigated. As the spread of capabilities has a strong geographical bias, we expect regions to develop new industries in which their neighbour regions are specialized. To test this hypothesis, we analyse the development of new industries in US states during the period 2000-2012. We show that a US state has a higher probability of developing a comparative advantage in a new industry if a neighbour state is specialized in that industry. We also show that neighbour US states have more similar export structures. This export similarity seems to be explained by higher social connectivity between neighbour states, as embodied in their bilateral migration patterns. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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129. Resemblance profiles as clustering decision criteria: Estimating statistical power, error, and correspondence for a hypothesis test for multivariate structure.
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Kilborn, Joshua P., Jones, David L., Peebles, Ernst B., and Naar, David F.
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CLUSTER analysis (Statistics) , *ECOLOGICAL software , *STATISTICAL power analysis , *MULTIVARIATE analysis , *STATISTICAL hypothesis testing - Abstract
Clustering data continues to be a highly active area of data analysis, and resemblance profiles are being incorporated into ecological methodologies as a hypothesis testing-based approach to clustering multivariate data. However, these new clustering techniques have not been rigorously tested to determine the performance variability based on the algorithm's assumptions or any underlying data structures. Here, we use simulation studies to estimate the statistical error rates for the hypothesis test for multivariate structure based on dissimilarity profiles ( DISPROF). We concurrently tested a widely used algorithm that employs the unweighted pair group method with arithmetic mean ( UPGMA) to estimate the proficiency of clustering with DISPROF as a decision criterion. We simulated unstructured multivariate data from different probability distributions with increasing numbers of objects and descriptors, and grouped data with increasing overlap, overdispersion for ecological data, and correlation among descriptors within groups. Using simulated data, we measured the resolution and correspondence of clustering solutions achieved by DISPROF with UPGMA against the reference grouping partitions used to simulate the structured test datasets. Our results highlight the dynamic interactions between dataset dimensionality, group overlap, and the properties of the descriptors within a group (i.e., overdispersion or correlation structure) that are relevant to resemblance profiles as a clustering criterion for multivariate data. These methods are particularly useful for multivariate ecological datasets that benefit from distance-based statistical analyses. We propose guidelines for using DISPROF as a clustering decision tool that will help future users avoid potential pitfalls during the application of methods and the interpretation of results. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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130. Rheumatoid Arthritis Naive T Cells Share Hypermethylation Sites With Synoviocytes.
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Rhead, Brooke, Holingue, Calliope, Cole, Michael, Shao, Xiaorong, Quach, Hong L., Quach, Diana, Shah, Khooshbu, Sinclair, Elizabeth, Graf, John, Link, Thomas, Harrison, Ruby, Rahmani, Elior, Halperin, Eran, Wang, Wei, Firestein, Gary S., Barcellos, Lisa F., and Criswell, Lindsey A.
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CONFIDENCE intervals , *FACTOR analysis , *RHEUMATOID arthritis , *SPECTROPHOTOMETRY , *STATISTICAL hypothesis testing , *SYNOVIAL membranes , *RECEIVER operating characteristic curves , *DATA analysis software , *DNA methylation , *DESCRIPTIVE statistics , *MANN Whitney U Test , *GENOTYPES , *CLUSTER sampling - Abstract
Objective To determine whether differentially methylated CpGs in synovium-derived fibroblast-like synoviocytes (FLS) of patients with rheumatoid arthritis (RA) were also differentially methylated in RA peripheral blood (PB) samples. Methods For this study, 371 genome-wide DNA methylation profiles were measured using Illumina HumanMethylation450 BeadChips in PB samples from 63 patients with RA and 31 unaffected control subjects, specifically in the cell subsets of CD14+ monocytes, CD19+ B cells, CD4+ memory T cells, and CD4+ naive T cells. Results Of 5,532 hypermethylated FLS candidate CpGs, 1,056 were hypermethylated in CD4+ naive T cells from RA PB compared to control PB. In analyses of a second set of CpG candidates based on single-nucleotide polymorphisms from a genome-wide association study of RA, 1 significantly hypermethylated CpG in CD4+ memory T cells and 18 significant CpGs (6 hypomethylated, 12 hypermethylated) in CD4+ naive T cells were found. A prediction score based on the hypermethylated FLS candidates had an area under the curve of 0.73 for association with RA case status, which compared favorably to the association of RA with the HLA-DRB1 shared epitope risk allele and with a validated RA genetic risk score. Conclusion FLS-representative DNA methylation signatures derived from the PB may prove to be valuable biomarkers for the risk of RA or for disease status. [ABSTRACT FROM AUTHOR]
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- 2017
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131. Regulation of Chondrocyte Survival in Mouse Articular Cartilage by p63.
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Taniguchi, Yuki, Kawata, Manabu, Ho Chang, Song, Mori, Daisuke, Okada, Keita, Kobayashi, Hiroshi, Sugita, Shurei, Hosaka, Yoko, Inui, Hiroshi, Taketomi, Shuji, Yano, Fumiko, Ikeda, Toshiyuki, Akiyama, Haruhiko, Mills, Alea A., Chung, Ung‐il, Tanaka, Sakae, Kawaguchi, Hiroshi, and Saito, Taku
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AGING , *ANIMAL experimentation , *ARTICULAR cartilage , *CARTILAGE cells , *HISTOLOGICAL techniques , *MICE , *OSTEOARTHRITIS , *POLYMERASE chain reaction , *RESEARCH funding , *STATISTICAL hypothesis testing , *STATISTICS , *T-test (Statistics) , *DATA analysis , *REVERSE transcriptase polymerase chain reaction , *DATA analysis software , *DESCRIPTIVE statistics , *IN vitro studies , *IN vivo studies - Abstract
Objective Transcription factor p63, of the p53 family, regulates cell proliferation, survival, and apoptosis in various cells and tissues. This study was undertaken to examine the expression and roles of p63 transcript variants in the mouse growth plate and articular chondrocytes. Methods For in vivo analyses, we generated Cre-mediated TAp63α-transgenic and TAp63γ-transgenic mice. To induce tissue-specific overexpression or deletion in chondrocytes, chondroprogenitor cells, or early limb bud mesenchymal cells, we used Col2a1-Cre, Sox9-Cre, and Prx1-Cre mice, respectively. We analyzed osteoarthritis (OA) development with aging or surgically induced instability in Prx1-Cre;p63fl/fl (P-conditional knockout) mice. Results Among major variants, TAp63α and TAp63γ are highly expressed in mouse primary costal and articular chondrocytes. The p63 protein was predominantly localized in the hypertrophic zone of the embryonic limb cartilage, and in the middle zone of articular cartilage. No obvious change was observed in skeletal growth of TAp63α-transgenic mice, Sox9-Cre;p63fl/fl, or P-conditional knockout mice, while that of TAp63γ-transgenic mice was impaired due to ectopic apoptosis and the resulting decreased number of chondrocytes. Expression of proapoptotic genes including bax, noxa, puma, and fas was increased in TAp63γ-transgenic mouse chondrocytes, and their transcription was probably sustained by p53 in p63-conditional knockout mouse chondrocytes because both proteins were coexpressed in the growth plate. In contrast, p53 was expressed in the superficial zone of articular cartilage, differently from p63. Notably, P-conditional knockout mice showed significant resistance to OA development, with suppression of chondrocyte apoptosis in the aging and surgical models. Conclusion We demonstrated regulation of chondrocyte survival in articular cartilage by p63. [ABSTRACT FROM AUTHOR]
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- 2017
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132. Comparative Assessment of the Different American College of Rheumatology/European League Against Rheumatism Remission Definitions for Rheumatoid Arthritis for Their Use as Clinical Trial End Points.
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Mack, Michael E., Hsia, Elizabeth, and Aletaha, Daniel
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C-reactive protein , *CHI-squared test , *COMPARATIVE studies , *CONFIDENCE intervals , *TEST validity , *FISHER exact test , *LONGITUDINAL method , *RESEARCH funding , *RHEUMATOID arthritis , *STATISTICAL hypothesis testing , *STATISTICS , *DATA analysis , *VISUAL analog scale , *DISEASE remission ,RESEARCH evaluation - Abstract
Objective The American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR) have defined remission using Boolean- or index-based criteria (i.e., a Simplified Disease Activity Index [SDAI] score of ≤3.3). We undertook this study to compare definitions of remission to inform choice of end points for future rheumatoid arthritis (RA) clinical trials, and we also included in our comparison the remission criterion of a score of ≤2.8 on the Clinical Disease Activity Index (CDAI). Methods We performed post hoc analyses on clinical remission rates using data from 2 infliximab trials (the ASPIRE [Active-Controlled Study of Patients Receiving Infliximab for the Treatment of Rheumatoid Arthritis of Early Onset] and ATTRACT [Anti-Tumor Necrosis Factor Trial in Rheumatoid Arthritis with Concomitant Therapy] trials) and 1 golimumab trial (the GO-FORWARD trial). We investigated stringency of the different remission definitions, their power to discriminate between active drug and comparator, and aspects of their internal and external validity. We also investigated population determinants of discriminatory power for a particular remission end point. Results In patients with early RA (the ASPIRE trial), ACR/EULAR Boolean, CDAI, and SDAI remission rates at 6-7 months were 4-6% for methotrexate (MTX) alone versus 11-14% for infliximab plus MTX. In patients with MTX-refractory active RA (the ATTRACT and GO-FORWARD trials), remission rates were ≤1% for comparator (add-on of placebo) versus 4-6% for add-on of infliximab in the ATTRACT trial and ≤3% for comparator (add-on of placebo) versus 11-13% for add-on of golimumab in the GO-FORWARD trial. Existing remission cut points of different measures were generally comparable, with the Boolean criteria being somewhat more stringent than the SDAI and CDAI criteria. Remission rates were similar across definitions, as was average statistical power (CDAI, 55.6%; Boolean, 59.9%; SDAI, 62.6%). Conclusion Remission is an ambitious primary end point for RA clinical trials, to be reserved for selected scenarios based on power considerations. The ACR/EULAR definitions are interchangeable, with slightly higher stringency of Boolean criteria over index-based criteria. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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133. Coronary Artery Calcification and Rheumatoid Arthritis: Lack of Relationship to Risk Alleles for Coronary Artery Disease in the General Population.
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Ferraz‐Amaro, Iván, Winchester, Robert, Gregersen, Peter K., Reynolds, Richard J., Wasko, Mary Chester, Oeser, Anette, Chung, Cecilia P., Stein, C. Michael, Giles, Jon T., and Bathon, Joan M.
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CORONARY heart disease risk factors , *C-reactive protein , *CARDIOVASCULAR diseases , *CONFIDENCE intervals , *STATISTICAL correlation , *QUESTIONNAIRES , *RESEARCH , *RESEARCH funding , *RHEUMATOID arthritis , *STATISTICAL hypothesis testing , *EFFECT sizes (Statistics) , *DATA analysis software , *DESCRIPTIVE statistics , *ODDS ratio , *MANN Whitney U Test , *DISEASE complications - Abstract
Objective Coronary artery disease (CAD) in the general population is characterized by an increased frequency of particular susceptibility single-nucleotide polymorphisms (SNPs). Because the frequency of CAD is increased among patients with rheumatoid arthritis (RA), we sought to determine whether the frequency of these SNPs is increased in RA patients with CAD, hypothesizing that RA could enhance CAD risk by acting through established genetic pathways predisposing to CAD. Methods Coronary artery calcification (CAC) as detected by computed tomography was used as a measure of CAD in 561 patients with RA. One hundred SNPs associated with CAD in the general population were genotyped or imputed, and their relationship to CAC was established through multiple regression analysis for individual SNPs and a genetic risk score representing their cumulative effect. Results Ninety-one CAD-related SNPs were genotyped successfully; of these, 81 exhibited no association with CAC (Agatston units) or different CAC categorizations, either individually or collectively, in the genetic risk score. Only rs579459 ( ABO) and rs17676451 ( HAL) had a consistent positive association between genotype and CAC, with a significant increase in the frequency of the effect allele in both homozygous and heterozygous genotype distributions. Five were variably negatively associated. Furthermore, a positive association between the Disease Activity Score in 28 joints and CAC was observed, and after adjustment for traditional cardiovascular risk factors, it was not modified by correcting for the CAD-related SNP genetic risk score. Conclusion The increased risk of CAC in patients with RA does not appear to operate primarily through established genetically regulated atherogenic mechanisms that are preponderant in the general population. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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134. Profile and reintegration experience of Ebola survivors in Guinea: a cross-sectional study.
- Author
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Delamou, Alexandre, Camara, Bienvenu Salim, Kolie, Jean Pe, Guemou, Achille Diona, Haba, Nyankoye Yves, Marquez, Shannon, Beavogui, Abdoul Habib, Delvaux, Therese, and Griensven, Johan
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EBOLA virus disease , *VIRUS diseases , *CHI-squared test , *STATISTICAL hypothesis testing , *PATIENTS , *CROSS-sectional method , *GUINEANS , *SOCIOECONOMIC factors , *EPIDEMICS , *PUBLIC welfare , *NEEDS assessment , *LONGITUDINAL method , *DISCHARGE planning , *DISEASE complications - Abstract
Objective: To describe the experience of Guinean Ebola virus disease (EVD) survivors in Guinea, up to ten months after discharge from the Ebola treatment unit.Methods: Cross-sectional study using a standardised semistructured questionnaire among survivors from Conakry and Coyah districts in 2015 in Guinea. We used proportions, mean (standard deviation) and median (interquartile range) to summarise the variables. The McNemar chi-square test was used to compare proportions.Results: The 121 EVD survivors interviewed had a median reintegration time from discharge of 18 weeks (IQR: 14-32 weeks). Most survivors were aged 15-44 years (87.6%) with secondary to higher level of education (68.6%), and 25.6% were healthcare workers. The majority reported a lower socio-economic status (90%), a less favourable work situation (79%) and psychological status (60%). About 31% reported physical health problems. Most survivors reported lower levels of reintegration with friends and at work place (72%) and lower acceptance by others in general (71%) in the period after the EVD as compared to the period before the EVD. Only 55 survivors (45.5%) were involved in one or more activities of the EVD response: participation in clinical studies on the EVD (44 survivors, 36.4%), community sensitisation (28 survivors, 23.1%) or work in Ebola treatment and/or transit centres (23 survivors, 21.7%).Conclusion: There is a need for a long-term follow-up of EVD survivors in Guinea and more efforts to support their social, professional and economic reintegration, especially in rural areas. [ABSTRACT FROM AUTHOR]- Published
- 2017
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135. Estimating standard errors in spatial panel models with time varying spatial correlation.
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Davenport, Frank
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STANDARD deviations , *SPATIAL analysis (Statistics) , *STATISTICAL correlation , *STATISTICAL hypothesis testing , *DISTRIBUTION (Probability theory) - Abstract
We connect time varying spatial correlation patterns to examples in the theoretical and empirical literature. Then we use simulation experiments to compare the performance of estimation techniques that use spatial weights matrices ( W) and those that do not. The results suggest that the pattern of time varying correlation does impact inference, but not as much as the W misspecification literature suggests. We find choosing the appropriate inferential method is less of a concern if the data generating process follows a hub-spoke correlation structure. Finally, we confirm earlier results that the cluster robust modifications proposed by Bester et al. (2011) perform well if the group sizes are chosen appropriately. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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136. STING Contributes to Abnormal Bone Formation Induced by Deficiency of DNase II in Mice.
- Author
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Baum, Rebecca, Sharma, Shruti, Organ, Jason M., Jakobs, Christopher, Hornung, Veit, Burr, David B., Marshak‐Rothstein, Ann, Fitzgerald, Katherine A., and Gravallese, Ellen M.
- Subjects
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ANALYSIS of bones , *ANALYSIS of variance , *ANIMAL experimentation , *ARTHRITIS , *BONE growth , *CYTOKINES , *DNA , *ENZYME-linked immunosorbent assay , *GENE expression , *GENES , *HISTOLOGICAL techniques , *MICE , *RESEARCH funding , *STAINS & staining (Microscopy) , *STATISTICAL hypothesis testing , *T-test (Statistics) , *PHENOTYPES , *OSTEOBLASTS , *DESCRIPTIVE statistics - Abstract
Objective Cytosolic DNA sensors detect microbial DNA and promote type I interferon (IFN) and proinflammatory cytokine production through the adaptor stimulator of IFN genes (STING) to resolve infection. Endogenous DNA also engages the STING pathway, contributing to autoimmune disease. This study sought to identify the role of STING in regulating bone formation and to define the bone phenotype and its pathophysiologic mechanisms in arthritic mice double deficient in DNase II and IFN-α/β/ω receptor (IFNAR) (DNase II−/−/IFNAR−/− double-knockout [DKO] mice) compared with controls. Methods Bone parameters were evaluated by micro-computed tomography and histomorphometry in DKO mice in comparison with mice triple deficient in STING, DNase II, and IFNAR and control mice. Cell culture techniques were employed to determine the parameters of osteoclast and osteoblast differentiation and function. NanoString and Affymetrix array analyses were performed to identify factors promoting ectopic bone formation. Results Despite the expression of proinflammatory cytokines that would be expected to induce bone loss in the skeleton of DKO mice, the results, paradoxically, demonstrated an accumulation of bone in the long bones and spleens, sites of erythropoiesis and robust DNA accrual. In addition, factors promoting osteoblast recruitment and function were induced. Deficiency of STING significantly inhibited bone accrual. Conclusion These data reveal a novel role for cytosolic DNA sensor pathways in bone in the setting of autoimmune disease. The results demonstrate the requirement of an intact STING pathway for bone formation in this model, a finding that may have relevance to autoimmune diseases in which DNA plays a pathogenic role. Identification of pathways linking innate immunity and bone could reveal novel targets for the treatment of bone abnormalities in human autoimmune diseases. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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137. Human Endogenous Retroviral Genetic Element With Immunosuppressive Activity in Both Human Autoimmune Diseases and Experimental Arthritis.
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Laska, Magdalena Janina, Troldborg, Anne, Hauge, Ellen‐Margrethe, Bahrami, Shervin, and Stengaard‐Pedersen, Kristian
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RNA analysis , *ANIMAL experimentation , *ARTHRITIS , *CHI-squared test , *ENZYME-linked immunosorbent assay , *GENES , *GENETICS , *INTERLEUKINS , *MEDICAL records , *MICE , *PEPTIDES , *RESEARCH funding , *RETROVIRUSES , *STATISTICAL hypothesis testing , *STATISTICS , *SYSTEMIC lupus erythematosus , *T-test (Statistics) , *DATA analysis , *CONTROL groups , *SEVERITY of illness index , *ELECTRONIC health records , *DESCRIPTIVE statistics , *MANN Whitney U Test , *KRUSKAL-Wallis Test - Abstract
Objective Human endogenous retroviruses (HERVs) are remnants of past retroviral infections in the human genome and have been implicated in different aspects of human biology. The aim of this study was to identify HERVs that are associated with the pathogenesis of rheumatic diseases such as systemic lupus erythematosus (SLE). Methods The study subjects included 45 female patients with SLE and 50 healthy controls matched for geographic area, age, and sex. Real-time reverse transcription-polymerase chain reaction analysis was used to examine the transcription levels of 11 genes with coding capacity for complete envelope (Env) protein in these individuals. In this way, 1 HERV locus was identified as a potential modulator of autoimmunity. The env gene encoded by this HERV locus was cloned and examined for the ability to express a functional protein with immunosuppressive potential. Results Expression of the env59 gene was negatively correlated with pathogenetic factors of human autoimmune rheumatic diseases, including such factors as the levels of interleukin-6 (IL-6) and Toll-like receptor 7. This gene was capable of encoding a fully functional Env glycoprotein that was found to contain a domain, the immunosuppressive (ISU) domain, that, when evaluated ex vivo in patients with SLE and those with rheumatoid arthritis as well as in animal models, showed strong antiinflammatory activity, including the ability to lower IL-6 levels. Conclusion The env59 gene has been adapted by the immune system as a control mechanism in autoimmunity. The peptides derived from the ISU domain contained in the Env59 protein may be useful as potentially new biologic treatments in rheumatic diseases such as SLE. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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138. Anifrolumab, an Anti-Interferon-α Receptor Monoclonal Antibody, in Moderate-to-Severe Systemic Lupus Erythematosus.
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Furie, Richard, Khamashta, Munther, Merrill, Joan T., Werth, Victoria P., Kalunian, Kenneth, Brohawn, Philip, Illei, Gabor G., Drappa, Jorn, Wang, Liangwei, and Yoo, Stephen
- Subjects
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THERAPEUTIC use of monoclonal antibodies , *TREATMENT effectiveness , *CONFIDENCE intervals , *HEALTH surveys , *MONOCLONAL antibodies , *PLACEBOS , *POLYMERASE chain reaction , *QUESTIONNAIRES , *RESEARCH funding , *STATISTICAL sampling , *STATISTICAL hypothesis testing , *SYSTEMIC lupus erythematosus , *LOGISTIC regression analysis , *EFFECT sizes (Statistics) , *RANDOMIZED controlled trials , *BLIND experiment , *SEVERITY of illness index , *DESCRIPTIVE statistics , *ODDS ratio - Abstract
Objective To assess the efficacy and safety of anifrolumab, a type I interferon (IFN) receptor antagonist, in a phase IIb, randomized, double-blind, placebo-controlled study of adults with moderate-to-severe systemic lupus erythematosus (SLE). Methods Patients (n = 305) were randomized to receive intravenous anifrolumab (300 mg or 1,000 mg) or placebo, in addition to standard therapy, every 4 weeks for 48 weeks. Randomization was stratified by SLE Disease Activity Index 2000 score (<10 or ≥10), oral corticosteroid dosage (<10 or ≥10 mg/day), and type I IFN gene signature test status (high or low) based on a 4-gene expression assay. The primary end point was the percentage of patients achieving an SLE Responder Index (SRI[4]) response at week 24 with sustained reduction of oral corticosteroids (<10 mg/day and less than or equal to the dose at week 1 from week 12 through 24). Other end points (including SRI[4], British Isles Lupus Assessment Group [BILAG]-based Composite Lupus Assessment [BICLA], modified SRI[6], and major clinical response) were assessed at week 52. The primary end point was analyzed in the modified intent-to-treat (ITT) population and type I IFN-high subpopulation. The study result was considered positive if the primary end point was met in either of the 2 study populations. The Type I error rate was controlled at 0.10 (2-sided), within each of the 2 study populations for the primary end point analysis. Results The primary end point was met by more patients treated with anifrolumab (34.3% of 99 for 300 mg and 28.8% of 104 for 1,000 mg) than placebo (17.6% of 102) ( P = 0.014 for 300 mg and P = 0.063 for 1,000 mg, versus placebo), with greater effect size in patients with a high IFN signature at baseline (13.2% in placebo-treated patients versus 36.0% [ P = 0.004] and 28.2% [ P = 0.029]) in patients treated with anifrolumab 300 mg and 1,000 mg, respectively. At week 52, patients treated with anifrolumab achieved greater responses in SRI(4) (40.2% versus 62.6% [ P < 0.001] and 53.8% [ P = 0.043] with placebo, anifrolumab 300 mg, and anifrolumab 1,000 mg, respectively), BICLA (25.7% versus 53.5% [ P < 0.001] and 41.2% [ P = 0.018], respectively), modified SRI(6) (28.4% versus 49.5% [ P = 0.002] and 44.7% [ P = 0.015], respectively), major clinical response (BILAG 2004 C or better in all organ domains from week 24 through week 52) (6.9% versus 19.2% [ P = 0.012] and 17.3% [ P = 0.025], respectively), and several other global and organ-specific end points. Herpes zoster was more frequent in the anifrolumab-treated patients (2.0% with placebo treatment versus 5.1% and 9.5% with anifrolumab 300 mg and 1,000 mg, respectively), as were cases reported as influenza (2.0% versus 6.1% and 7.6%, respectively), in the anifrolumab treatment groups. Incidence of serious adverse events was similar between groups (18.8% versus 16.2% and 17.1%, respectively). Conclusion Anifrolumab substantially reduced disease activity compared with placebo across multiple clinical end points in the patients with moderate-to-severe SLE. [ABSTRACT FROM AUTHOR]
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- 2017
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139. Lidocaine Pretreatment Reduces the Discomfort of Intranasal Midazolam Administration: A Randomized, Double-blind, Placebo-controlled Trial.
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Smith, David, Cheek, Hugh, Denson, Brenda, Pruitt, Christopher M., and Heard, Kennon
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INTRANASAL medication ,LIDOCAINE ,LOCAL anesthetics ,LONGITUDINAL method ,MIDAZOLAM ,PLACEBOS ,PREANESTHETIC medication ,STATISTICAL hypothesis testing ,CONTINUING medical education ,DATA analysis ,RANDOMIZED controlled trials ,CONTINUING education units ,BLIND experiment ,MANN Whitney U Test - Abstract
Objective Intranasal ( IN) midazolam is a commonly prescribed medication for pediatric sedation and anxiolysis. One of its most frequently encountered adverse effects is discomfort with administration. While it has been proposed that premedicating with lidocaine reduces this undesirable consequence, this combination has not been thoroughly researched. The objective of our study was to assess whether topical lidocaine lessens the discomfort associated with IN midazolam administration. Methods This was a double-blind, randomized, placebo-controlled trial performed in an urban, academic pediatric emergency department. Children 6-12 years of age who were receiving IN midazolam for procedural sedation received either 4% lidocaine or 0.9% saline (placebo) via mucosal atomizer. Subjects were subsequently given IN midazolam in a similar fashion and then rated their discomfort using the Wong-Baker FACES Pain Rating Scale ( WBS). The primary endpoint of WBS score was analyzed with a two-tailed Mann-Whitney U-test, with p < 0.05 considered statistically significant. Results Seventy-seven patients were enrolled over a consecutive 8-month period. One child was excluded from analysis due to a discrepancy in recording the drug identification number. Study groups were similar in regard to demographic information and indication for sedation. Subjects who received IN lidocaine reported less discomfort with IN midazolam administration (median WBS = 3, interquartile range [ IQR] = 0-6) than those who received placebo (median WBS = 8, IQR = 2-9; p = 0.006). Conclusions Premedication with topical lidocaine reduces the discomfort associated with administration of IN midazolam (ClinicalTrials.gov, NCT02396537). [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
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140. A graphical framework for model selection criteria and significance tests: refutation, confirmation and ecology.
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Aho, Ken, Derryberry, Dewayne, Peterson, Teri, and O'Hara, Robert B.
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INFORMATION theory in biology ,BAYES' estimation ,AKAIKE information criterion ,STATISTICAL hypothesis testing ,P-value (Statistics) - Abstract
In this study, we use a novel graphical heuristic to compare the way four methods: significance testing, two popular information-theoretic approaches ( AIC and BIC) and Good's Bayes/non-Bayes compromise (an underutilized hypothesis testing approach whose demarcation criterion adjusts for n), evaluate the merit of competing hypotheses, for example H
0 and HA ., A primary goal of our work is to clarify the concept of strong consistency in model selection. Explicit considerations of this principle (including the strong consistency of BIC) are currently limited to technical derivations, inaccessible to most ecologists. We use our graphical framework to demonstrate, in simple terms, the strong consistency of both BIC and Good's compromise., Our framework also locates the evaluated metrics (and ICs in general) along a conceptual continuum of hypothesis refutation/confirmation that considers n, parameter number and effect size. Along this continuum, significance testing and particularly AIC are refutative for H0 , whereas Good's compromise and particularly BIC are confirmatory for the true hypothesis., Our work graphically demonstrates the well-known asymptotic bias of significance tests for HA , and the incorrectness of using statistically non-consistent methods for point hypothesis testing. To address these issues, we recommend: (i) dedicated confirmatory methods with strong consistency like BIC for use in point hypothesis testing and confirmatory model selection; (ii) significance tests for use in exploratory/refutative hypothesis testing, particularly when conjoined with rational approaches (e.g. Good's compromise, power analyses) to account for the effect of n on P-values; and (iii) asymptotically efficient methods like AIC for exploratory model selection. [ABSTRACT FROM AUTHOR]- Published
- 2017
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141. A haemostatic technique using silicone gel dressing for burn surgery.
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Osuka, Akinori, Kuroki, Yuichi, and Ueyama, Masashi
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BURNS & scalds ,PHARMACEUTICAL gels ,SURGICAL hemostasis ,SCIENTIFIC observation ,SILICONES ,STATISTICAL hypothesis testing ,SURGICAL dressings ,T-test (Statistics) ,TIME ,RETROSPECTIVE studies - Abstract
Significant blood loss and high rates of transfusion remain ongoing concerns in burn surgery. We have reported a haemostatic technique using silicone gel dressing to minimise bleeding during tangential excision in burn surgery. The purpose of this study was to identify the efficacy of our novel haemostatic technique for burn surgery. This study was a retrospective observational study. From 1 April 2011 to 31 March 2015, we collated data including pre- and 24-hour postoperative haemoglobin levels from patients over 15 years of age who underwent tangential excision for burn injuries. We also collected data on the amounts of measured blood loss, blood transfusions, excised areas, harvest areas and duration of surgeries. The collected data were divided into a conventional group and a silicone gel dressing group. Then, we analysed the differences between the two groups. During the study period, 357 patients were admitted to our burn centre, and 60 operations (44 patients) were performed by tangential excision. The conventional group comprised 28 operations (20 patients), and the silicone gel dressing group comprised 32 operations (26 patients). Excised areas and harvested areas were significantly larger in the silicone gel dressing group than in the conventional group. The amount of blood loss per percent excised and the number of units of blood transfused were significantly lower in the silicone gel dressing group. Duration of the surgeries was almost the same between the two groups. Application of our new technique during tangential excision for burn injuries resulted in a remarkable reduction in blood loss and transfusion requirements. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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142. Pin1-Targeted Therapy for Systemic Lupus Erythematosus.
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Wei, Shuo, Yoshida, Nobuya, Finn, Greg, Kozono, Shingo, Nechama, Morris, Kyttaris, Vasileios C., Zhen Zhou, Xiao, Tsokos, George C., and Ping Lu, Kun
- Subjects
- *
ANALYSIS of variance , *ANIMAL experimentation , *CELLULAR signal transduction , *FLOW cytometry , *IMMUNOBLOTTING , *INTERFERONS , *MICE , *PROBABILITY theory , *RESEARCH funding , *STATISTICAL hypothesis testing , *SYSTEMIC lupus erythematosus , *T-test (Statistics) , *PHENOTYPES , *DATA analysis software , *SIGNAL peptides , *DESCRIPTIVE statistics , *LOG-rank test , *CHEMICAL inhibitors - Abstract
Objective Systemic lupus erythematosus (SLE) is a debilitating autoimmune disease affecting multiple organs in the body, but therapeutic options are still very limited and often come with adverse effects. Increasing evidence has underlined an important role of the Toll-like receptor 7 (TLR-7)/TLR-9/interleukin-1 receptor-associated kinase 1 (IRAK-1)/interferon regulatory factor 7 (IRF-7) pathway in the development and progression of SLE. Notably, the prolyl isomerase Pin1 is an essential regulator of IRAK-1 in TLR-7/TLR-9 signaling, but its role in SLE is unknown. We undertook this study to determine whether Pin1 is activated and plays any role in the development and treatment of SLE. Methods Activation of Pin1 and TLR-7/TLR-9/IRAK-1/IRF-7 signaling was determined in various cell types among peripheral blood mononuclear cells from healthy controls and SLE patients. The effects of Pin1 and TLR signaling on SLE development were determined using validated Pin1 short hairpin RNA (shRNA), Pin1 genetic knockout, and the small-molecule Pin1 inhibitor all- trans-retinoic acid (ATRA) in immune cells and in several strains of lupus-prone mice. Results We found abnormal activation of Pin1 and its downstream targets IRAK-1 and IRF-7 in SLE patients. Furthermore, inhibition of Pin1 using either validated Pin1 shRNA or ATRA blocked TLR-7-induced activation of IRAK-1 and IRF-7 in SLE patient-derived immune cells. Moreover, in multiple lupus-prone animals, both Pin1 knockout and ATRA strikingly attenuated the expression of autoimmunity, including skin lesions, lymphadenopathy, splenomegaly, glomerulonephritis, proteinuria, and production of anti-double-stranded DNA antibodies and CD4−CD8− T cells, and also prolonged overall survival in MRL/ lpr and B6. lpr mice. Conclusion Pin1 plays a critical role in the development of SLE, and Pin1-targeted therapy offers a promising new strategy for treating SLE. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
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143. Elevated IgA Plasmablast Levels in Subjects at Risk of Developing Rheumatoid Arthritis.
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Kinslow, Jennifer D., Blum, Lisa K., Deane, Kevin D., Demoruelle, M. Kristen, Okamoto, Yuko, Parish, Mark C., Kongpachith, Sarah, Lahey, Lauren J., Norris, Jill M., Robinson, William H., and Holers, V. Michael
- Subjects
- *
AUTOANTIBODY analysis , *RHEUMATOID arthritis risk factors , *DNA analysis , *AUTOANTIBODIES , *B cells , *CHI-squared test , *COMPARATIVE studies , *FISHER exact test , *PROBABILITY theory , *RESEARCH funding , *RHEUMATOID arthritis , *STATISTICAL hypothesis testing , *T-test (Statistics) , *EARLY diagnosis , *DATA analysis software , *MICROARRAY technology , *GENE expression profiling , *DESCRIPTIVE statistics , *MANN Whitney U Test , *KRUSKAL-Wallis Test , *ONE-way analysis of variance - Abstract
Objective The disease process in rheumatoid arthritis (RA) starts years before the clinical diagnosis is made, and elevated levels of disease-specific autoantibodies can be detected during this period. Early responses to known or novel autoantigens likely drive the eventual production of pathogenic autoimmunity. Importantly, the presence of disease-specific autoantibodies can identify individuals who are at high risk of developing RA but who do not currently have arthritis. The goal of the current study was to characterize plasmablasts from individuals at risk of developing RA. Methods We investigated antibody-secreting plasmablasts derived from a well-characterized cohort of individuals who were at risk of developing RA, based on RA-related serum autoantibody positivity, as compared to patients with early (<1 year) seropositive RA as well as healthy control subjects. The plasmablast antibody repertoires of at-risk subjects were analyzed using DNA barcode-based methods with paired heavy- and light-chain gene sequencing. Cells were single-cell sorted, the cell- and plate-specific DNA barcodes were sequentially added, and next-generation sequencing was performed. Results Total plasmablast levels were similar in the antibody-positive (1%) and control (0.4-1.6%) groups. However, increased frequencies of IgA+ versus IgG+ plasmablasts were observed in the antibody-positive group (39% IgA+ and 37% IgG+) as compared to other groups (1-9% IgA+ and 71-87% IgG+). Paired antibody sequences from antibody-positive subjects revealed cross-isotype clonal families and similar sequence characteristics in the IgA and IgG plasmablast repertoires. Antibody-positive individuals also demonstrated elevated serum levels of IgA isotype anti-cyclic citrullinated peptide 3 antibodies. Conclusion The IgA plasmablast dominance in these antibody-positive individuals suggests that a subset of RA-related autoantibodies may arise from mucosal immune responses and may be involved in early disease pathogenesis in individuals who are at risk of developing RA. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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144. Trabecular Bone Score in Patients With Chronic Glucocorticoid Therapy-Induced Osteoporosis Treated With Alendronate or Teriparatide.
- Author
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Saag, Kenneth G., Agnusdei, Donato, Hans, Didier, Kohlmeier, Lynn A., Krohn, Kelly D., Leib, Edward S., MacLaughlin, Edmund J., Alam, Jahangir, Simonelli, Christine, Taylor, Kathleen A., and Marcus, Robert
- Subjects
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CHI-squared test , *DRUG side effects , *GLUCOCORTICOIDS , *OSTEOPOROSIS , *PROBABILITY theory , *RESEARCH funding , *STATISTICAL hypothesis testing , *T-test (Statistics) , *BONE density , *RANDOMIZED controlled trials , *TREATMENT effectiveness , *DATA analysis software , *ALENDRONATE , *PHOTON absorptiometry , *TERIPARATIDE , *PHARMACODYNAMICS - Abstract
Objective To determine the effect of alendronate (ALN) and teriparatide on trabecular bone score (TBS) in patients with glucocorticoid-induced osteoporosis. Methods Patients with chronic glucocorticoid therapy-induced osteoporosis (median 7.5 mg/day prednisone equivalent for ≥90 days) were randomized to receive oral ALN 10 mg/day (n = 214) or subcutaneous teriparatide 20 μg/day (n = 214) for 36 months; 118 patients in the ALN group and 123 patients in the teriparatide group completed treatment. Dual x-ray absorptiometry (DXA) results for 53 patients receiving ALN and 56 patients receiving teriparatide who had DXA scans with adequate resolution to perform TBS analysis and completed 36 months of therapy were blindly analyzed for TBS at baseline and 3, 6, 12, 18, 24, and 36 months. Results In teriparatide-treated patients, TBS was significantly increased at 18 months compared to baseline, and by 36 months had increased 3.7% ( P < 0.05). In ALN-treated patients, there was not a significant change in TBS compared to baseline at any time point. Changes in lumbar spine bone mineral density (BMD) measured by DXA in the subgroup with TBS data were similar to BMD results in the overall study population. At 36 months, increases in lumbar spine BMD were 5.5% and 10.3% in patients treated with ALN and teriparatide, respectively. Conclusion In patients with glucocorticoid-induced osteoporosis, both ALN and teriparatide increased lumbar spine BMD. However, trabecular bone score significantly increased with teriparatide but did not significantly change with ALN. The pathogenesis of glucocorticoid-induced osteoporosis is predominantly reduced bone formation. TBS may represent a sensitive measure to discriminate treatment effects of an anabolic versus an antiresorptive drug in glucocorticoid-induced osteoporosis. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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145. How Distractor Objects Trigger Referential Overspecification: Testing the Effects of Visual Clutter and Distractor Distance.
- Author
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Koolen, Ruud, Krahmer, Emiel, and Swerts, Marc
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ALGORITHMS , *COMPUTATIONAL linguistics , *STATISTICAL hypothesis testing , *HYPOTHESIS , *REASONING - Abstract
In two experiments, we investigate to what extent various visual saliency cues in realistic visual scenes cause speakers to overspecify their definite object descriptions with a redundant color attribute. The results of the first experiment demonstrate that speakers are more likely to redundantly mention color when visual clutter is present in a scene as compared to when this is not the case. In the second experiment, we found that distractor type and distractor color affect redundant color use: Speakers are most likely to overspecify if there is at least one distractor object present that has the same type, but a different color than the target referent. Reliable effects of distractor distance were not found. Taken together, our results suggest that certain visual saliency cues guide speakers in determining which objects in a visual scene are relevant distractors, and which not. We argue that this is problematic for algorithms that aim to generate human-like descriptions of objects (such as the Incremental Algorithm), since these generally select properties that help to distinguish a target from all objects that are present in a scene. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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- View/download PDF
146. Improving the analysis of routine outcome measurement data: what a Bayesian approach can do for you.
- Author
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Vries, Rivka M., Meijer, Rob R., Bruggen, Vincent, and Morey, Richard D.
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BAYESIAN analysis , *MENTAL health screening , *MEASUREMENT errors , *STATISTICAL reliability , *STATISTICAL hypothesis testing ,PSYCHIATRIC research - Abstract
Since recent decades, clinicians offering interventions against mental problems must systematically collect data on how clients change over time. Since these data typically contain measurement error, statistical tests have been developed which should disentangle true changes from random error. These statistical tests can be subdivided into two types: classical tests and Bayesian tests. Over the past, there has been much confusion among analysts regarding the questions that are answered by each of these tests. In this paper we discuss each type of test in detail and explain which questions are, and which are not, answered by each of the types of tests. We then apply a test of each type on an empirical data set and compare the results. Copyright © 2015 John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]
- Published
- 2016
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147. On Time-Variance Analysis: Reply.
- Author
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SCHWARTZ, ROBERT A. and WHITCOMB, DAVID K.
- Subjects
MATHEMATICAL models of investments ,SECURITIES ,RATE of return ,AUTOCORRELATION (Statistics) ,TIME series analysis ,ANALYSIS of variance ,MATHEMATICAL models of finance ,STATISTICAL hypothesis testing ,INTERVAL analysis ,CENTRAL limit theorem - Abstract
The article refers to questions raised by Meir Schneller and discusses time-variance analysis, time dimensions, and the effect of autocorrelation in time-variance relationships. Three time dimensions are defined: the differencing interval; the short period; and the calendar span. The differencing interval is the measuring interval--they are the same interval preceded by different words and are the single interval in the equation for the behavior of security returns. An explanation for the paradox of a one-period stationary return and the Central Limit Theorem are mentioned.
- Published
- 1979
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148. Beta Regression Tendencies: Statistical and Real Causes.
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ELGERS, PIETER T., HALTINER, JAMES R., and HAWTHORNE, WILLIAM H.
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BETA (Finance) ,FINANCIAL statistics ,ESTIMATION bias ,STATISTICAL significance ,LEAST squares ,STATISTICAL bias ,STATISTICAL correlation ,STATISTICAL reliability ,ESTIMATES ,STATISTICAL hypothesis testing - Abstract
The tendency for ordinary least squares beta estimates to regress towards one over successive time periods is by now a familiar empirical phenomenon. The regression tendency is due in part to estimation error, termed the "order bias" by Blume. After correction of beta estimates for order bias, any remaining regression can be attributed to real causes, such as capital restructure or asset changes. This note is intended to clarify the nature of the real cause of beta regression tendencies. Blume has documented the fact that successive portfolio betas exhibit a statistically significant residual mean regression after correction for order bias. The mere fact that true beta is imperfectly correlated through time is sufficient to account for this phenomenon. However, Blume speculates that "the risk of existing projects may tend to become less extreme over time" or that "new projects taken on by firms may tend to have less extreme risk characteristics than existing projects" (p. 795). Since Blume's evidence pertains only to the issue of beta nonstationarity, and is entirely neutral on the question of whether the cross-sectional variability of true betas is diminishing through time, the speculation deserves to be tested. Tables 1 and 2 provide evidence relevant to the hypothesis. In Table 1, Blume's results are substantially replicated and extended to cover a subsequent seven-year period (July, 1968–June, 1975). The time series is then reversed (so that period 2 is interpreted as the earlier period, and period i the later period), and adjusted in the same manner to correct for order-bias. A statistically significant mean regression is found to persist in both directions after the order-bias correction. Moreover, the estimated slope coefficient of the equation describing the mean regression is essentially the same in both directions for each period examined. This evidence reflects the fact that true betas are imperfectly correlat... [ABSTRACT FROM AUTHOR]
- Published
- 1979
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149. COMMENTS ON SINGLE VALUED DURATION MEASURES.
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CARR, J. L., HALPERN, P. J., and MCCALLUM, J. S.
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CASH flow ,HYPOTHESIS ,BONDS (Finance) ,MATURITY (Finance) ,STATISTICAL hypothesis testing ,TERMS & phrases - Abstract
The authors comment on the article "Duration Fallacy," by Miles Livingston and John Caks, which they suggest criticizes the method they developed in a previous paper to deal with duration problems. They state their use of the term "duration" was concerning the general problem concerning coupon bonds as the phrase "term to maturity" concerns only the date of final expected cash flows, rather than the standard usage as defined by Frederick Macaulay. They mention that term to maturity ignores all other cash flow timings. They state that Macaulay descriptive summary statistics are of little use in hypothesis testing.
- Published
- 1978
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150. When controversies in null hypothesis significance testing prove to be controversial.
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Sedgwick, Philip M., Hammer, Anne, Kesmodel, Ulrik Schiøler, and Pedersen, Lars Henning
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NULL hypothesis , *STATISTICAL hypothesis testing , *FALSE positive error , *PARAMETERS (Statistics) - Abstract
It would have best read "...when 20 independent statistical hypothesis tests are performed the maximum probability of a type I error occurring is approximately 0.64".3 Frane questions the validity of the statement: "Studies with large sample sizes are important because as sample size approaches the population size, the sample estimates have increased accuracy when estimating the population parameters". I Sir i , We thank Dr. Frane for his Letter to the Editor1 in response to our commentary "Current controversies: Null hypothesis significance testing."2 We believe the wording in our commentary regarding the probability of a type I error occurring when 20 hypothesis tests are performed may have been unfortunate. As sample sizes approach the population size and more data are collected, then sample estimates will become more accurate in relation to the population parameters that they are estimating. [Extracted from the article]
- Published
- 2022
- Full Text
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