Search

Studies on the postnatal growth of free-ranging bats can be based on multiple recaptures of marked individuals of known age (longitudinal sampling) or derived from measurements of captured pups with unknown birth dates (cross-sectional sampling). We therefore used individuals of Geoffroy’s bat Myotis emarginatus in a case study to test the hypothesis that these two methods yield similar data on growth rates and growth derivatives. We followed postnatal growth in body mass, forearm length, and total epiphyseal gap in 24 tagged neonates sampled 10 times (via 143 cases of longitudinal sampling) and compared finding with those deriving from cross-sectional sampling carried out on the same occasions among 138 non-tagged neonates of the same colony. A generalized estimating equation relating to the first 3 weeks of postnatal growth indicated that initial values (y-intercepts) for forearm length and body mass did not differ significantly between groups sampled in the two ways (P > 0.05), while rates of growth characterized by these parameters were found to differ significantly (P

Physical and environmental diseases affect elderly insomnia. Sleep needs are basic human needs, including elderly. However, many elderly people have difficulty sleeping (insomnia). The purpose of this study was to determine the relationship of physical illness and environmental problems to insomnia experienced by the elderly. Research design using cross sectional Sampling with purposive sampling technique, with a total of 34 people. Data analysis using univariate and bivariate. The results showed that there was a relationship between physical illness and environmental problems with elderly insomnia. Keywords: elderly insomnia, environmental problems, physical illness

Participation in family planning will contribute significantly of population growth and treatment of reproductive. Factors that cause low men in the KB-lack of knowledge, the husband's attitude about ignorance and practice and the understanding that KB affairs is a woman's business. The purpose of this study was to determine the relationship of husband knowledge about contraceptive methods MOP (male surgery method) with the attitude of the husband in the KB MOP work area Health Center Sei Heat Batam Year 2017. This research is an analytical descriptive with cross sectional Sampling using purposive sampling method. This study was conducted in May-June 2017 with the number of respondents as many as 99 people. Data analysis using Chi-Square technique.From the resear ch result, the majority of husbands with less knowledge are 43 people (43,4%) and majority of husbands have negative attitude that is 66 people (66,7%). From the statistical test results obtained p = 0,000

Subgroup A 1 and A 2 are the most important in the blood group A. Subgroup A 1 has the A antigen more than A 2 subgroup, the A 2 subgroup can cause misidentification of blood group due to poor A antigen and genetic variation possessed. Misidentification of the blood group will increase the risk of transfusion reactions. This research aims to describe the A 1 and A 2 subgroup population in Kulon Progo district. This study was conducted with a cross sectional sampling technique. The sample in this study were taken from donors of blood group A in Kulon Progo Red Cross. Identification of A 1 and A 2 subgroup is done by using lectin ( Dolichos biflorus extract). The result of the examination of 53 samples showed that 96,2% was A 1 subgroup and 3,8% was A 2 subgroup. Key words : Subgroup A 1 , Subgroup A 2 , Population, Kulon Progo

Objectives: This study is aimed to look at the distribution of the quality of periapical radiographs produced by students using conventional films and instant films at the Faculty of Dentistry Universitas Brawijaya radiology installation. Material and Methods: The method used in this research is analytic descriptive with cross sectional sampling method. The research datas were primary data with a total of 20 periapical radiographs from each method. Data was analyzed by Spearman test in SPSS software. Results: Data were analysed using the Spearman rho correlation test which showed the results of ρ = 0,5. The results of periapical radiographs using conventional films as much as 65% were very good, 25% were good, and 10% were not acceptable. The results of periapical radiographs using instant film were 70% good, 15% very good, and 15% were not acceptable. Conclusion: There is no difference in the quality of the results of conventional periapical radiographs and instant films in the radiology installation of the Faculty of Dentistry Universitas Brawijaya Malang.

Nonparametric estimation of the transition probability matrix of a progressive multi‐state model is considered under cross‐sectional sampling. Two different estimators adapted to possibly right‐censored and left‐truncated data are proposed. The estimators require full retrospective information before the truncation time, which, when exploited, increases efficiency. They are obtained as differences between two survival functions constructed for sub‐samples of subjects occupying specific states at a certain time point. Both estimators correct the oversampling of relatively large survival times by using the left‐truncation times associated with the cross‐sectional observation. Asymptotic results are established, and finite sample performance is investigated through simulations. One of the proposed estimators performs better when there is no censoring, while the second one is strongly recommended with censored data. The new estimators are applied to data on patients in intensive care units (ICUs). Spanish Ministry of Economy and Competitiveness | Ref. MTM2014-55966-P The Israel Science Foundation | Ref. Grant No. 519/14

Clinical studies using complex sampling often involve both truncation and censoring, where there are options for the assumptions of independence of censoring and event and for the relationship between censoring and truncation. In this paper, we clarify these choices, show certain equivalences, and provide examples.

This paper considers semiparametric estimation of the Cox proportional hazards model for right-censored and length-biased data arising from prevalent sampling. To exploit the special structure of length-biased sampling, we propose a maximum pseudo-profile likelihood estimator, which can handle time-dependent covariates and is consistent under covariate-dependent censoring. Simulation studies show that the proposed estimator is more efficient than its competitors. A data analysis illustrates the methods and theory. Copyright 2012, Oxford University Press.

We used dendrochronological techniques to develop an optimal sampling strategy for the purpose of investigating the history of red oak borer (Enaphalodes rufulus [Haldeman]) population patterns within northern red oaks (Quercus rubra L.). We cut the entire length of three northern red oak tree boles into cross-sections, sanded top and bottom surfaces of each cross-section, and dated all scars within each bole. Our goal was to devise a strategy to reduce the amount of bole sampled without compromising the data necessary to accurately estimate historical population patterns of red oak borer. When we tested four possible sampling strategies and compared them with the entire-tree data sets from which they originated, we found no statistical differences in the distribution of scar counts by year. We also assessed processing time and found that compared with sampling an entire host bole, sampling strategies that include the lower 20% or 30% of boles would reduce labor efforts by 55–63%. We suggest that development of similar sampling methods for other bark or wood-boring species may be possible if the relationship between insect life history and annual tree-ring formation, as well as the general spatial and temporal distribution of insect evidence within trees, is known.

TITLE The relationship of dental health knowledge and dental caries prevalence in 3rd to 5th level of school children in SD Muhammadiyah Sangonan II Godean Yogyakarta ABSTRACT Knowledge play an important part to build oral and dental hygiene behaviour in children. Dental caries is one of the hard tissue disease caused by bacterial activity that will make dental hard tissue soften and cavity will appear. The purpose of this research was to find the relation between oral and dental health knowledge and dental caries cases among pupils grade III-IV SD Muhammadiyah Sangonan II, Godean. It was an analytical survey research, with cross sectional sampling. The independent variable was knowledge about oral and dental health, and the dependent variable was total caries number among pupils grade III-IV. It used total population sampling, all of the pupils in grade III-IV, with total 60 children, as the subjects. Questionnaire and direct examination used for the data collection. The data analysis for hypothesis testing used Spearman rank. Most of the children have good knowledge about oral and dental health, 49 childs (81,7%) could answer correctly 15-20 questions. On the other hand, most of the children (34 childs or 56,7%) have ≥3 caries or in category ‘many caries numbers’. There was no corellation between oral and dental health knowledge and total caries number among pupils grade III – V SD Muhammadiyah Sangonan II Godean, with significancy 0,408 (sig≥0.05).

Introduction.Medical students experience significant psychological stress and are therefore at higher risk of using sedatives. There are currently no studies describing the prevalence of sedative drug use among medical students in Saudi Arabia. The aim of this study was to evaluate the prevalence and factors associated with sedative drug use among medical students in Saudi Arabia.Materials and Methods.A cross-sectional convenience sampling study gathered data by anonymous questionnaire from students enrolled at the King Saud University College of Medicine in 2011. The questionnaires collected data regarding social and demographic variables, sleep patterns, and the use of stimulant and sedative drugs since enrollment. Sedatives were defined as any pharmaceutical preparations that induce sleep.Results and Discussion.Of the 729 students who returned questionnaires, 17.0% reported sedative drug use at some time since enrollment. Higher academic year, lower grade point average, regular exercise, fewer hours of sleep per day, poorer quality of sleep, and the presence of sleeping disorders were found to be significantly associated with sedative drug use.Conclusions.Further study is required to increase our understanding of sedative drug use patterns in this relatively high-risk group, as such understanding will help in the development of early intervention programs.

Estimates of postnatal growth rates and age based on data collected from free-ranging little brown myotis (Myotis lucifugus) captured sequentially at the same colony in the same year were used to compare longitudinal (mark–recapture) and cross-sectional (grab) sampling methods. Analyses of these data indicate that cross-sectional sampling significantly underestimates growth rates for length of forearm, body mass, and length of epiphyseal gap. Equations based on cross-sectional samples significantly overestimated ages of young, as compared with equations based on the longitudinal method. These results support the hypothesis that cross-sectional sampling is unreliable for deriving postnatal growth curves for free-ranging bats and emphasize the importance of using longitudinal data to derive growth rates and estimates of age during the postnatal period.

This article focuses on two aspects of event history analysis that have interested Jan Hoem since his early career: the effect on event history analysis methodology of non-standard sampling patterns, here illustrated by various types of sampling at a cross-section in calendar time; and the application of T. Schweder’s concept of local dependence, analogous to the econometric concept of Granger causality. Cross-sectional sampling in the Lexis diagram was studied by Keiding (1991; 2006) and Lund (2000), who gave several examples. We present a brief outline of the status of this area. Local dependence was defined by Schweder (1970) as an asymmetric dependence concept between two binary variables, made possible by incorporating the times of their occurrences in a Markov chain framework. Courgeau and Lelievre (1992) gave a detailed exposition of the central role of this approach in demography, followed up by Blossfeld and Rohwer (2002). Aalen et al. (1980) applied the approach to cross-sectional data from the prevalent cohort of patients with a rare skin disease. The example combines the analysis of interaction between two life history events with a non-standard sampling pattern. I briefly summarize the present state of this approach and outline further analyses of the data presented by Aalen et al. (2009) as well as of a confirmatory study.

SUMMARY The competing risks illness–death model describes the dynamics of healthy subjects who may move to an “illness” state before entering into one of several competing terminal states. A motivating example concerns patients in a hospital who may acquire infections during their stay, where the competing terminal states are discharged alive and death in the hospital. We consider a cross-sectional sampling of independent competing risks illness–death processes in which data are subject to length bias and censoring and develop estimators for functionals of the underlying distribution such as the joint probability of the terminal state and illness (infection) and cumulative incidence functions. We apply the methodology to infection data obtained in a cross-sectional study of patients hospitalized in intensive care units.

Time to pregnancy, the duration that a couple waits from initiating attempts to conceive until conception occurs, is regarded as one of the direct measures of natural fecundity. Statistical tools for designing and analyzing time-to-pregnancy studies belong to the general area of survival analysis, but several special features have developed. Keywords: discrete-time survival analysis; truncation in survival analysis; frailty; prospective sampling; retrospective sampling; cross-sectional sampling; backward recurrence time

Sun, Cui & Tiwari (2002) studied the asymptotic behaviour of certain goodness-of-fit tests in the presence of biased sampling and right censoring. The author illustrates that unfortunately, an assumption made by Sun, Cui and Tiwari on the independence between failure and censoring time fails to hold in many important applications, which limits the applicability of their results. Sun, Cui & Tiwari (2002) ont etudie le comportement asymptotique de certains tests d'adequation en presence de biais d'echantillonnage et de censure a droite. L'auteur montre que malheureusement, une hypothese faite par Sun, Cui et Tiwari quant a l'independance entre les temps de deces et de censure ne tient pas dans plusieurs applications importantes, ce qui limite la portee de leurs resultats.

This document contains raw laboratory data concerning the testing done at the Columbia River at the Hanford Site.