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Background: The pre-season preparatory period is considered key for optimizing the physical fitness levels needed to withstand congested match periods and preventing injuries during the regular soccer season. This study contrasted the effects s of neuromuscular training (NMT) versus an endurance-dominated training (ET) program conducted during the preseason on measures of physical fitness and injury occurrence in female soccer players. Methods: Twenty-four female soccer players aged 17.0 ± 1.3 years from a professional soccer club participated in this study. Players were randomly assigned to NMT (n = 12) or ET (n = 12) groups according to their playing position. The preseason intervention program lasted six weeks, with three weekly sessions with a duration of 45–60 min per session. Exercises in the NMT group included muscle strengthening exercises, plyometrics, agility and dynamic stability exercises, while the ET group practiced a traditional pre-season training program consisting of running and sprinting exercises, fartlek, and high-intensity interval training. The training volumes were similar in the two study groups. Anthropometric measurements, physical fitness tests (i.e., linear and change-of-direction speed, muscle strength and power tests) and the overall injury rate per 1000 h of exposure (training, match) were recorded throughout the season. Results: No between group differences were found at pre (T1). Significant group-by-time interactions were observed for the 5, 10, and 30-m linear sprint speed tests (p < 0.001, 2.16 < d < 2.58), the T-test (p = 0.024, d = 1.03), the squat (p < 0.001, d = 4.04), and the countermovement jump test (p < 0.001, d = 2.21), the Loughborough soccer passing test (LSPT) (p = 0.019, d = 1.08), and the 1-RM back squat test (p < 0.001, d = 2.53). Post-hoc tests indicated that NMT provided larger improvements for SJ, CMJ, 1-RM back squat, the 5-m sprint, 10-m sprint, 30-m sprint, T-test and LSPT compared to ET (1.07 > d > 2.77). The injury rate across the season was significantly lower in the NMT (5.1/1000 h exposure) compared to ET (11.8/1000 h exposure) (p = 0.014). Conclusions: The findings support that six-weeks of preseason NMT versus ET induced larger performance improvements, and significantly reduced injury occurrence in elite female soccer players. Key points: • Our results indicate that the integration of 45 to 60 min of preseason neuromuscular training, three times per week, for 6 weeks, can improve physical fitness and prevent injuries in young female soccer players. • The present study demonstrated that the neuromuscular training program can reduce the incidence injury rate by more than 50% and the burden by more than 65% compared to the endurance-dominated training. • Neuromuscular training is an effective approach during the preseason period to improve diverse measures of physical fitness and to reduce injury occurrence. • Preseason neuromuscular training appears to improve the fitness level of female soccer players and as such could allow them to compete at the high level. [ABSTRACT FROM AUTHOR]

This study was conducted to determine whether facial photographs obtained simultaneously with radiographs improve radiologists' detection rate of wrong-patient errors, when they are explicitly asked to include the photographs in their evaluation. Radiograph-photograph combinations were obtained from 28 patients at the time of portable chest radiography imaging. From these, pairs of radiographs were generated. Each unique pair consisted of one new and one old (comparison) radiograph. Twelve pairs of mismatched radiographs (i.e., pairs containing radiographs of different patients) were also generated. In phase 1 of the study, 5 blinded radiologist observers were asked to interpret 20 pairs of radiographs without the photographs. In phase 2, each radiologist interpreted another 20 pairs of radiographs with the photographs. Radiologist observers were not instructed about the purpose of the photographs but were asked to include the photographs in their review. The detection rate of mismatched errors was recorded along with the interpretation time for each session for each observer. The two-tailed Fisher exact test was used to evaluate differences in mismatch detection rates between the two phases. A p value of <0.05 was considered significant. The error detection rates without (0/20 = 0 %) and with (17/18 = 94.4 %) photographs were different ( p = 0.0001). The average interpretation times for the set of 20 radiographs were 26.45 (SD 8.69) and 20.55 (SD 3.40) min, for phase 1 and phase 2, respectively (two-tailed Student t test, p = 0.1911). When radiologists include simultaneously obtained photographs in their review of portable chest radiographs, there is a significant improvement in the detection of labeling errors. No statistically significant difference in interpretation time was observed. This may lead to improved patient safety without affecting radiologists' throughput. [ABSTRACT FROM AUTHOR]

Background: Most studies on sepsis were conducted in developed countries. The aim of this study is to report on a series of patients with sepsis in a tertiary hospital in a developing country. Methods: Patients admitted through the emergency department of a single university-based institution between January 2008 and June 2012, with a final diagnosis of sepsis, bacteremia, or septic shock, were retrieved. A sample of 97 patients was selected. Vital signs at presentation, number of SIRS criteria, use of vasopressors and steroids, and in-hospital mortality were recorded. Results: The mean age was 70.09 ± 16.82, ranging from 19 to 96 years; 48.5 % were females and 51.5 % were males; 42.3 % of the patients were found to be bacteremic. IV fluid requirement during the first 6 h was 1.75 ± 1.96 l. The time for antibiotic initiation was 3.43 ± 4.48 h, with 87.6 % of the antibiotics initiated in the emergency department. Norepinephrine was the most commonly used vasopressor (38.1 %) followed by dopamine (8.2 %), and the inotrope dobutamine (4.1 %); 45.3 % of the patients were admitted to the intensive care unit (ICU), and the remaining 54.7 % were managed on the general practice unit (GPU). A total of 30 (30.9 %) septic patients died. The 28-day mortality was 20.6 %. Deceased patients had greater vasopressor use, a longer stay in the ICU (p = 0.001), and a longer time to norepinephrine use (p = 0.004). Conclusions: This is the first study providing an in-depth analysis of sepsis patients in a developing country, looking at in-hospital mortality, SIRS criteria utility, and at the overall sepsis management. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to explore the association between the impaired nutritional status and frailty in acute hospitalised elderly patients by using two tools, the MNA®-SF (Mini Nutritional Assessment® short-form) and the SHARE-FI (Frailty Instrument for Primary Care of the Survey of Health, Ageing and Retirement in Europe). Design: Cross-sectional study. Setting: Acute hospitalised, community-dwelling elderly patients were recruited at internal medicine wards in Vienna, Austria. Participants: 133 men (39%) and women (61%) aged 74 (65-97) years. Measurements: MNA®-SF was used to investigate malnutrition (<7 points) and patients at risk of malnutrition (8 to 11 points). By using the SHARE-FI, subjects were classified as frail, pre-frail or robust. A factor analysis was applied to identify overlaps between the MNA®-SF and SHARE-FI items. Internal consistency of different dimensions was assessed by using Cronbach's Alpha. Results: Malnutrition or risk of malnutrition was found in 76.7% of the total sample and in 46.8% of robust, in 69.0% of pre-frail, and in 93.0% of frail participants. Frailty or prefrailty was found in 75.9% of the total sample and in 45.1% of the subjects with no risk of malnutrition, in 80.9% of subjects at risk of malnutrition, and in 94.1% of malnourished patients. The two used tools show overlaps in three dimensions: (1) nutrition problems, (2) mobility problems and (3) anthropometric items with a moderate to strong internal consistency (Cronbach's Alpha of 0.670, 0.834 and 0.946, respectively). 64.7% of the total sample (79.5% of frail and 87.9% of malnourished subjects) would participate in a home-based muscle training and nutritional intervention program. Conclusions: This study underlines the association and the overlap between frailty and impaired nutritional status. There is a high readiness to participate in a program to tackle the problems associated with malnutrition and frailty, especially in those, who would benefit most from it. [ABSTRACT FROM AUTHOR]

Study design:Experimental laboratory investigation of spinal cord conductivity alterations in a rat model of ischemic spinal cord injury (SCI).Objective:To observe the epidural spinal cord stimulation-induced electromyography responses, and to investigate the possible alterations of spinal cord conduction velocity (SCCV) and compound muscle action potentials (CMAPs) after ischemic SCI in rats.Settings:Adnan Menderes University, Institute of Health Science, Aydin, Turkey.Methods:SCI was induced by transient occlusion of the abdominal aorta in male Sprague-Dawley rats. Spinal cord histopathology was examined to determine neuronal damage and Tarlov scale was used to grade locomotor functions. Epidural electrical stimulation of spinal cord was performed by monopolar needle electrodes sequentially at L1-L2 and L5-L6 levels, and CMAPs were recorded from the left gastrocnemius muscle by surface electrodes. Amplitudes and durations of CMAPs were evaluated and SCCVs were calculated by analyzing the latency difference of CMAPs.Results:Ischemia-induced SCI resulted in significant reduction of Tarlov scores and a significant decline in number of viable neurons. Similarly, a significant decrement was observed in SCCV following spinal cord ischemia.Conclusion:This study demonstrated that measurement of SCCV via epidural electrical stimulation is possible and displays a significant decline after spinal cord ischemia in rats. We suggest that this method can be beneficial to quantify neuronal damage after experimental ischemic SCI. [ABSTRACT FROM AUTHOR]

Various concepts of mean shape previously unrelated in the literature are brought into relation. In particular, for non-manifolds, such as Kendall's 3D shape space, this paper answers the question, for which means one may apply a two-sample test. The answer is positive if intrinsic or Ziezold means are used. The underlying general result of manifold stability of a mean on a shape space, the quotient due to an proper and isometric action of a Lie group on a Riemannian manifold, blends the slice theorem from differential geometry with the statistics of shape. For 3D Procrustes means, however, a counterexample is given. To further elucidate on subtleties of means, for spheres and Kendall's shape spaces, a first-order relationship between intrinsic, residual/Procrustean and extrinsic/Ziezold means is derived stating that for high concentration the latter approximately divides the (generalized) geodesic segment between the former two by the ratio 1:3. This fact, consequences of coordinate choices for the power of tests and other details, e.g. that extrinsic Schoenberg means may increase dimension are discussed and illustrated by simulations and exemplary datasets. [ABSTRACT FROM AUTHOR]

To test whether forming and memorizing more action plans has larger effects than generating fewer plans. In a randomized controlled trial with five intervention groups and one control group, 478 participants were asked to form one, two, three, four, or five action plans, or to complete questionnaires only (control group). One week later, behavior change was measured and participants of the intervention groups completed a free recall task. Outcome measures are daily intake of fruit and vegetables as well as recall of plans. Fruit and vegetable intake increased with higher numbers of plans, and was significantly larger in groups that formed four ( d = 0.36) or five plans ( d = 0.48) as compared to controls. The sum of recalled plans reflected the number of generated plans, but was unrelated to behavior change. Generating multiple plans benefits behavior change, but to be implemented they need not be recalled. [ABSTRACT FROM AUTHOR]

Study design:Lithium has attracted much attention as a neuroregenerative agent for spinal cord injury in animal models. We hypothesized that the lithium can be beneficial to patients with spinal cord injury. The safety and pharmacokinetics of lithium has been studied in our earlier phase I clinical trial, indicating its safety. This is a phase II clinical trial to evaluate its efficacy on chronic spinal cord injury patients.Objectives:The aim of this study was to investigate the efficacy of lithium on chronic spinal cord injury patients.Setting:A major spinal cord injury rehabilitation center in Beijing, China.Methods:Randomized, double-blind, placebo-controlled 6-week parallel treatment arms with lithium carbonate and with placebo. A total of 40 chronic spinal cord injury subjects were recruited. Oral lithium carbonate was titrated or placebo was simulated to maintain the serum lithium level of 0.6-1.2 mmol l−1 for 6 weeks, followed by a 6-month follow-up. The functional outcomes and the neurological classifications, as well as the safety parameters, adverse events and pharmacokinetic data were carefully collected and monitored.Results:No significant changes in the functional outcomes and the neurological classifications were found. The only significant differences were in the pain assessments using visual analog scale comparing the lithium and the placebo group. No severe adverse event was documented in the study.Conclusion:The lithium treatment did not change the neurological outcomes of patients with chronic spinal cord injury. It is worth to investigate whether lithium is effective in the treatment of neuropathic pain in chronic spinal cord injury.Sponsorship:China Spinal Cord Injury Network Company Limited. [ABSTRACT FROM AUTHOR]

Objective: To assess the effectiveness of health and nutrition program (NutriAlz) versus usual care on functional level in elderly people with dementia living at home, as well as on clinical practice related to nutrition and on the caregiver's burden. Design: Cluster randomized multi-centre study with one-year follow-up. Setting: 11 Alzheimer outpatients and day care centres (Barcelona, Spain). Participants: Nine hundred and forty six home-living Alzheimer patients with identified caregiver were consecutively recruited (intervention group: 6 centres, 448 patients vs control group: 5 centres, 498 patients). Intervention: The intervention was a teaching and training intervention on health and nutrition program, NutriAlz, directed both to physician and main caregiver, as well as persons affected by Alzheimer's disease or other dementias, including a standardised protocol for feeding and nutrition. Main Outcome Measures: The main outcome measure was the reduction in the loss of autonomy (Activities of daily living (ADL/IADL) scales) assessed at 6 and 12 months. Secondary outcomes measures were Improvement in nutritional status (Mini Nutritional Assessment (MNA), BMI, and weight changes), and caregiver burden (Zarit scale). Results: The one-year assessment was completed for 293 patients (65.4%) in the intervention group and 363 patients (72.9%) in the control group (usual care). The annual rate of ADL change was −0.83 vs −0.62 (p=0.984), and the caregiver's subjective burden 0.59 vs 2.36 (p=0.681) in intervention and control group, respectively. MNA, however, showed an improvement (+0.46 vs −0.66, p=0.028), suggesting an effective nutritional behaviour. Conclusion: The NutriAlz program had no effect on functional decline in Alzheimer disease patients living at home over one year, but reduced the risk for malnutrition, as recommendations concerning diet and exercise were provided. [ABSTRACT FROM AUTHOR]

In this paper we investigate an advanced variant of the classical (Jackson) tandem queue, viz. a two-node system with server slowdown. By this mechanism, the service speed of the upstream queue is reduced as soon as the number of jobs in the downstream queue reaches some pre-specified threshold. We focus on the estimation of the probability of overflow in the downstream queue before the system becomes empty, starting from any given state in the state space. The principal contribution of this paper is that we construct importance sampling schemes to estimate these probabilities in case they are small; in particular: (1) We use powerful heuristics to identify the exponential decay rate of the probability under consideration, and verify this result by applying sample-path large deviations techniques. (2) Based on these heuristics we develop a change of measure to be used in importance sampling. (3) We prove that this scheme is asymptotically efficient, using a shorter and more straightforward method than usually provided in the literature. Unfortunately, this scheme is difficult to use in practice, therefore (4) we propose an algorithm that offers considerable computational advantage over the first scheme. For this scheme we provide a proof of asymptotic efficiency for certain parameter settings, as well as numerical results showing that the scheme works well for all parameters. [ABSTRACT FROM AUTHOR]

The use of religious/spiritual resources may increase when dealing with the stress of a cancer diagnosis. However, there has been very little research conducted into changes in religious/spiritual beliefs and practices as a result of a cancer diagnosis outside the USA. The aim of this study was to examine the impact of a breast cancer diagnosis on patients' religious/spiritual beliefs and practices in the UK where religious practice is different. The study used two methods. One compared the religious/spiritual beliefs and practices of 202 patients newly diagnosed with breast cancer with those of a control group of healthy women ( n = 110). The other examined patients' perceived change in religious/spiritual beliefs and practices at the time of surgery with those in the year prior to surgery. The aspects of religiousness/spirituality assessed were: levels of religiosity/spirituality, strength of faith, belief in God as well as private and public practices. Patient's perceived their belief in God, strength of faith and private religious/spiritual practices to have significantly increased shortly after surgery compared with the year prior to surgery. However, there were no significant differences in religious/spiritual beliefs and practices between patients and healthy participants. Change scores demonstrated both a reduction and an increase in religious/spiritual beliefs and practices. Although belief in God, strength of faith and private religious/spiritual practices were perceived by patients to be significantly higher after their cancer diagnosis, no significant differences in religious/spiritual beliefs and practices were found between the cancer group at the time of surgery and the control group. Different methodologies appear to produce different results and may explain contradictions in past US studies. Limitations of this study are discussed and suggestions for future research are made. [ABSTRACT FROM AUTHOR]

previous pilot study suggested that rizatriptan reduces motion sickness induced by complex vestibular stimulation. In this double-blind, randomized, placebo-controlled study we measured motion sickness in response to a complex vestibular stimulus following pretreatment with either rizatriptan or a placebo. Subjects included 25 migraineurs with or without migraine-related dizziness (23 females) aged 21-45 years (31.0 ± 7.8 years). Motion sickness was induced by off-vertical axis rotation in darkness, which stimulates both the semicircular canals and otolith organs of the vestibular apparatus. Results indicated that of the 15 subjects who experienced vestibular-induced motion sickness when pretreated with placebo, 13 showed a decrease in motion sickness following pretreatment with rizatriptan as compared to pretreatment with placebo ( P < 0.02). This significant effect was not seen when subjects were exposed to more provocative vestibular stimulation. We conclude that the serotonin agonist, rizatriptan, reduces vestibular-induced motion sickness by influencing serotonergic vestibular-autonomic projections. [ABSTRACT FROM AUTHOR]

For the problems of statistical estimation of unknown probability, consideration was given to determination of the sample volume guaranteeing the desired accuracy of estimation with the desired confidence probability. This problem was solved using an approach which was developed earlier by the present authors based on constructing guaranteeing confidence intervals for estimation of the unknown parameters in the cases where the central limit theorem is used to construct the asymptotic confidence intervals. The guaranteeing confidence intervals differ from the asymptotic intervals in a correction allowing for the error of the central limit theorem in the case of using a finite sample. Explicit expressions for the guaranteeing sample volume were given. [ABSTRACT FROM AUTHOR]

Virtually all quantitative microdata used by social scientists derive from samples that incorporate clustering, stratification, and weighting adjustments (Kish 1965, 1992). Such data can yield standard error estimates that differ dramatically from those derived from a simple random sample of the same size. Researchers using historical U.S. census microdata, however, usually apply methods designed for simple random samples. The resulting p values and confidence intervals could be inaccurate and could lead to erroneous research conclusions. Because U.S. census microdata samples are among the most widely used sources for social science and policy research, the need for reliable standard error estimation is critical. We evaluate the historical microdata samples of the Integrated Public Use Microdata Series (IPUMS) project from 1850 to 1950 in order to determine (1) the impact of sample design on standard error estimates, and (2) how to apply modern standard error estimation software to historical census samples. We exploit a unique new data source from the 1880 census to validate our methods for standard error estimation, and then we apply this approach to the 1850-1870 and 1900-1950 decennial censuses. We conclude that Taylor series estimation can be used effectively with the historical decennial census microdata samples and should be applied in research analyses that have the potential for substantial clustering effects. [ABSTRACT FROM AUTHOR]

This study examined the measurement equivalence of the original paper-based vertical format of the EQ-5D visual analog scale (EQ VAS) with a touch-screen computer-based horizontal format. A total of 314 subjects were administered two modes of the EQ VAS in a randomized crossover design. One mode was the original paper-based 20 cm vertical EQ VAS; the other mode was touch-screen-based. Measurement equivalence was assessed by testing the 95% confidence interval of the mean differences from an equivalence threshold of −3 to +3 points on the VAS and evaluating the intraclass correlation coefficient (ICC). The adjusted mean (SE) EQ VAS score was 80.96 (0.87) on the paper and 79.59 (0.85) on the touch-screen. The mean (CI) difference between scores on the two formats was 1.37 with a confidence interval of 0.175–2.559, wholly contained within the equivalence interval. The ICC was 0.75, indicating acceptable agreement between the two modes. Almost a third (30.1%) of the respondents reported identical scores on both formats. These results provide evidence for the measurement equivalence of this EQ VAS touch-screen administration mode with the original paper mode. [ABSTRACT FROM AUTHOR]

In this paper, we use smoothed empirical likelihood methods to construct confidence intervals for hazard and density functions under right censorship. Some empirical log-likelihood ratios for the hazard and density functions are obtained and their asymptotic limits are derived. Approximate confidence intervals based on these methods are constructed. Simulation studies are used to compare the empirical likelihood methods and the normal approximation methods in terms of coverage accuracy. It is found that the empirical likelihood methods provide better inference. [ABSTRACT FROM AUTHOR]

Data that are skewed and contain a relatively high proportion of zeros can often be modelled using a delta-lognormal distribution. We consider three methods of calculating a 95% confidence interval for the mean of this distribution, and use simulation to compare the methods, across a range of realistic scenarios. The best method, in terms of coverage, is that based on the profile-likelihood. This gives error rates that are within 1% (lower limit) or 3% (upper limit) of the nominal level, unless the sample size is small and the level of skewness is moderate to high. Our results will also apply to the delta-lognormal linear model, when we wish to calculate a confidence interval for the expected value of the response variable, given the value of one or more explanatory variables. We illustrate the three methods using data on red cod densities, taken from a fisheries trawl survey in New Zealand. [ABSTRACT FROM AUTHOR]

For sample sizes from 5 to 100, the bias of the scale parameter was investigated for probability estimators, P = ( i − a)/( n + b), which yield unbiased estimates of the shape parameter. A class of unbiased estimators for both the shape and scale parameters was developed for each sample size. In addition, the percentage points of the distribution of unbiased estimate of the shape parameter were determined for all sample sizes. The distribution of the scale parameter was found to be normal by using the Anderson-Darling goodness-of-fit test. How the results can be used to establish confidence intervals on both the shape and scale parameters are demonstrated in the paper. [ABSTRACT FROM AUTHOR]

LÁJER (2007) notes that, to investigate phytosociological and ecological relationships, many authors apply traditional inferential tests to sets of relevés obtained by non-random methods. Unfortunately, this procedure does not provide reliable support for hypothesis testing because non-random sampling violates the assumptions of independence required by many parametric inferential tests. Instead, a random sampling scheme is recommended. Nonetheless, random sampling will not eliminate spatial autocorrelation. For instance, a classical law of geography holds that everything in a piece of (biotic) space is interrelated, but near objects are more related than distant ones. Because most ecological processes that shape community structure and species coexistence are spatially explicit, spatial autocorrelation is a vital part of almost all ecological data. This means that, independently from the underlying sampling design, ecological data are generally spatially autocorrelated, violating the assumption of independence that is generally required by traditional inferential tests. To overcome this drawback, randomization tests may be used. Such tests evaluate statistical significance based on empirical distributions generated from the sample and do not necessarily require data independence. However, as concerns hypothesis testing, randomization tests are not the universal remedy for ecologists, because the choice of inadequate null models can have significant effects on the ecological hypotheses tested. In this paper, I emphasize the need of developing null models for which the statistical assumptions match the underlying biological mechanisms. [ABSTRACT FROM AUTHOR]

LÁJER (2007) raised the problem of using a non-random sample for statistical testing of plant community data. He argued that this violates basic assumptions of the tests, resulting thus in non-significant results. However, a huge part of present-day knowledge of vegetation science is still based on non-random, preferentially collected data of plant communities. I argue that, given the inherent limits of preferential sampling, a change of approach is now necessary, with the adoption of sampling based on random principles seeming the obvious choice. However, a complete transition to random-based sampling designs in vegetation science is limited by the yet undefined nature of plant communities and by the still diffused opinion that plant communities have a discrete nature. Randomly searching for such entities is almost impossible, given their dependence on scale of observation, plot size and shape, and the need for finding well-defined types. I conclude that the only way to solve this conundrum is to consider and study plant communities as operational units. If the limits of the plant communities are defined operationally, they can be investigated using proper sampling techniques and the collected data analyzed using adequate statistical tools. [ABSTRACT FROM AUTHOR]

The currently dominating hypothetico-deductive research paradigm for ecology has statistical hypothesis testing as a basic element. Classic statistical hypothesis testing does, however, present the ecologist with two fundamental dilemmas when field data are to be analyzed: (1) that the statistically motivated demand for a random and representative sample and the ecologically motivated demand for representation of variation in the study area cannot be fully met at the same time; and (2) that the statistically motivated demand for independence of errors calls for sampling distances that exceed the scales of relevant pattern-generating processes, so that samples with statistically desirable properties will be ecologically irrelevant. Reasons for these dilemmas are explained by consideration of the classic statistical Neyman-Pearson test procedure, properties of ecological variables, properties of sampling designs, interactions between properties of the ecological variables and properties of sampling designs, and specific assumptions of the statistical methods. Analytic solutions to problems underlying the dilemmas are briefly reviewed. I conclude that several important research objectives cannot be approached without subjective elements in sampling designs. I argue that a research strategy entirely based on rigorous statistical testing of hypotheses is insufficient for field ecological data and that inductive and deductive approaches are complementary in the process of building ecological knowledge. I recommend that great care is taken when statistical tests are applied to ecological field data. Use of less formal modelling approaches is recommended for cases when formal testing is not strictly needed. Sets of recommendations, "Guidelines for wise use of statistical tools", are proposed both for testing and for modelling. Important elements of wise-use guidelines are parallel use of methods that preferably belong to different methodologies, selection of methods with few and less rigorous assumptions, conservative interpretation of results, and abandonment of definitive decisions based a predefined significance level. [ABSTRACT FROM AUTHOR]

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I show that three parametric-bootstrap (PB) applications that have been proposed for phylogenetic analysis, can be misleading as currently implemented. First, I show that simulating a topology estimated from preliminary data in order to determine the sequence length that should allow the best tree obtained from more extensive data to be correct with a desired probability, delivers an accurate estimate of this length only in topological situations in which most preliminary trees are expected to be both correct and statistically significant, i.e. when no further analysis would be needed. Otherwise, one obtains strong underestimates of the length or similarly biased values for incorrect trees. Second, I show that PB-based topology tests that use as null hypothesis the most likely tree congruent with a pre-specified topological relationship alternative to the unconstrained most likely tree, and simulate this tree for P value estimation, produce excessive type I error (from 50% to 600% and higher) when they are applied to null data generated by star-shaped or dichotomous four-taxon topologies. Simulating the most likely star topology for P value estimation results instead in correct type-I-error production even when the null data are generated by a dichotomous topology. This is a strong indication that the star topology is the correct default null hypothesis for phylogenies. Third, I show that PB-estimated confidence intervals (CIs) for the length of a tree branch are generally accurate, although in some situations they can be strongly over- or under-estimated relative to the “true” CI. Attempts to identify a biased CI through a further round of simulations were unsuccessful. Tracing the origin and propagation of parameter estimate error through the CI estimation exercise, showed that the sparseness of site-patterns which are crucial to the estimation of pivotal parameters, can allow homoplasy to bias these estimates and ultimately the PB-based CI estimation. Concluding, I stress that statistical techniques that simulate models estimated from limited data need to be carefully calibrated, and I defend the point that pattern-sparseness assessment will be the next frontier in the statistical analysis of phylogenies, an effort that will require taking advantage of the merits of black-box maximum-likelihood approaches and of insights from intuitive, site-pattern-oriented approaches like parsimony. [ABSTRACT FROM AUTHOR]

Normal theory procedures for calculating upper confidence limits (UCL) on the risk function for continuous responses work well when the data come from a normal distribution. However, if the data come from an alternative distribution, the application of the normal theory procedures may lead serious over- or under-coverage depending upon the alternative distribution. In this paper we conduct simulation studies to investigate the sensitivity of three normal theory UCL procedures to departures from normality. Data from several gamma, reciprocal gamma, and lognormal distributions are considered. The normal theory procedures are applied to both the raw data and the log-transformed data. [ABSTRACT FROM AUTHOR]

We revisit and update the autoregressive-ouput-analysis method for constructing a confidence interval for the steady-state mean of a simulated process by using Rissanen's predictive least-squares criterion to estimate the autoregressive order of the process. This order estimator is strongly consistent when the output is autoregressive. The order estimator is combined with the standard autoregressive-output-analysis method to form a confidenceinterval procedure. Alternatives for estimating the degrees of freedom for the procedure are investigated. The main result is an asymptotically valid confidence-interval procedure that, empirically, has good small-sample properties. [ABSTRACT FROM AUTHOR]

This paper starts from the premise that the concept of income inequality is ill-defined, and hence, it studies the measurement of income inequality from a fuzzy set theoretical point of view. It is argued that the standard (fuzzy) transitivity concepts are not compatible with fuzzy inequality orderings which respect Lorenz ordering. For instance, we show that there does not exist a max-mm transitive fuzzy relation on a given income distribution space which ranks distributions unambiguously according to the Lorenz criterion whenever they can actually be ranked by it. Weakening the imposed transitivity concept, it is possible to escape from the noted impossibility theorems. We introduce some alternative transitivity concepts for fuzzy relations, and subsequently, construct a class of fuzzy orderings which preserve Lorenz ordering and satisfy these alternative transitivities. It is also shown that fuzzy measurement can be used to construct confidence intervals for the crisp conclusions of inequality indices. [ABSTRACT FROM AUTHOR]