Non-lethal measurement of pectoral fin aspect ratio in coral-reef fishes

This study describes a novel method for measuring pectoral fin aspect ratio (AR) on live coral-reef fishes and tests the method against traditional measurements taken from a dissected fin. No significant differences were detected among repeated fin measurements, which validates the accuracy (intact v. dissected) and precision (repeatability over several days) of fin AR measurements on live fishes. One exception highlighted issues that may arise when working with species prone to fin damage.     

Tests for profile analysis of paired curves based on friedman ranking methods

Two nonparametric tests are proposed for the comparison of a paired sample of response curves with T congruent time points. The first procedure rank transforms each curve and tests the homogeneity of the resulting pair of averaged rank vectors. The second procedure rank transforms each pair of curves and tests the homogeneity of the related pair of averaged rank vectors. The first test detects only pure interactions; the second test checks if any difference exists between the rank curves. Both tests are presented in finite and asymptotic as well as in combined (by T singular tests) and multivariate form.     

医学实验中常见设计类型的辨析及统计方法的合理选用

目的帮助医学研究工作者提高对常见统计应用识别能力,提高对统计学的正确利用率。方法：明确阐述秒种常见医学实验设计类型的异同点和应用场合,揭示常见统计应用错误的实质和危害性。结果：给出不适合用ｔ检验取代方差分析的充足理由和正确运用统计学的基本要领。结论：要提高实际工作者的统计学应用水平。需要经常对其进行统计培养,积极引导与统计学工作者开展科研协作。     

Estimates of the genetic parameters of turkey body weight using random regression analysis

Random regression (RR) analysis has been recommended to estimate the genetic parameters of longitudinal data. The objective of this study was to evaluate the growth of turkeys using RR models. Data were collected from 957 turkeys and included 15,478 individual body weight recorded during the first week of life and between weeks 2 and 32 by 2-week intervals. To take into account the repeated measurements of weight for each animal, a specific overall growth curve was modelled using a cubic smoothing spline. Animal deviation to this curve was also modelled using an RR function. All data were analysed with the ASReml package. The results showed an increase in heritability estimates over the trajectory and peaked at 0.60 around 20 to 32 weeks of age. Genetic correlations showed that turkeys could be selected at earlier time points, at 12 weeks of age, in order to increase the growth rate. In general, genetic correlation estimates were higher among adjacent ages, decreasing markedly with the increase of distance between ages. Negative genetic correlations were observed between ages.     

High-frequency metabolite profiling and the incidence of recurrent cardiac events in patients with post-acute coronary syndrome

Abstract

Purpose: The aim of this study was to study temporal changes in metabolite profiles in patients with post-acute coronary syndrome (ACS), in particular prior to the development of recurrent ACS (reACS).

Methods: BIOMArCS (BIOMarker study to identify the Acute risk of a Coronary Syndrome) is a prospective study including patients admitted for ACS, who underwent high-frequency blood sampling during 1-year follow-up. Within BIOMArCS, we performed a nested case-cohort analysis of 158 patients (28 cases of reACS). We determined 151 metabolites by nuclear magnetic resonance in seven (median) blood samples per patient. Temporal evolution of the metabolites and their relation with reACS was assessed by joint modelling. Results are reported as adjusted (for clinical factors) hazard ratios (aHRs).

Results: Median age was 64 (25th–75th percentiles; 56–72) years and 78% were men. After multiple testing correction (p?<?0.001), high concentrations of extremely large very low density lipoprotein (VLDL) particles (aHR 1.60/SD increase; 95%CI 1.25–2.08), very large VLDL particles (aHR 1.60/SD increase; 95%CI 1.25–2.08) and large VLDL particles (aHR 1.56/SD increase; 95%CI 1.22–2.05) were significantly associated with reACS. Moreover, these longitudinal particle concentrations showed a steady increase over time prior to reACS. Among the other metabolites, no significant associations were observed.

Conclusion: Post-ACS patients with persistent high concentrations of extremely large, very large and large VLDL particles have increased risk of reACS within 1?year.     

Joint modelling of repeated measurements and event time: Application to performance traits and survival of lambs bred in sub-humid tropics

We considered the analysis of a study for Dorper, Red Maasai and crossbred lambs born over a period of 6 years at the Diani Estate, Kenya. The study was designed to compare survival and performance traits of genotypes with differing susceptibilities to helminthiasis. The available data include information on time to death and repeated measurements of body weight, packed cell volume (PCV) and faecal egg count (FEC) of the animals. In the paper, we consider joint modelling of the survival time and the repeated measurements. Such an approach allows to account for the possible association between the survival and repeated measurement processes. The advantages and limitations of the joint modelling are discussed and illustrated using the Diani Estate study data.     

Model building and testing for the change-over design

The two-period cross-over design is discussed within the framework of univariate and multivariate analysis of variance technique; the relations between both procedures are explained. It is shown that all hypotheses of interest can be tested if the design is regarded as a special case of a repeated measurement design. Some features of the n-period change-over design are explained by discussing the model and hypotheses of a three-period design.     

Comparing Two Samples of Response Curves by Nonparamètric Tests of Predicted Order

Starting from MOSTELLER'S (1955) one-sample test of predicted order, some two-sample versions are proposed for comparing nonparametrically a treatment group (m response curves) with a control group (n response curves) as to a predicted shape represented by a specified rank order. The tests are applied to two groups of learning curves.     

Defining and Detecting Second Order Correlations in Repeated Measurements Designs

It is shown that 3-point response curves from N individuals imply a second order correlation (triplet correlation) between the 3 series of repeated measurements if the curves are clustered as to their shapes. Coefficients are defined and tests are suggested for triplet correlations. Nonparametric alternatives to ANOVA are discussed for repeated measurement designs involving shapeclustered response curves.     

The power of statistical tests using field trial count data of nontarget organisms in environmental risk assessment of genetically modified plants

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An application of isotonic longitudinal marginal regression to monitoring the healing process

This paper discusses marginal regression for repeated ordinal measurements that are isotonic over time. Such data are often observed in longitudinal studies on healing processes in which, due to recovery, the status of patients only improves or remains the same. We show how this prior information can be used to construct appropriate and parsimoniously parametrized marginal models. As a second aspect, we also incorporate nonparametric fitting of covariate effects via a penalized quasi-likelihood or general estimating equation approach. We illustrate our methods by an application to sports-related injuries.     

Single subject (small N) research designs and zoo research

This paper presents single case (small N) research designs as a design option for research in zoos. Because of the small numbers of animals in zoos, traditional large group designs using inferential statistics are often not feasible. Single subject research designs are discussed with respect to logic, specific design options, and validity. Specific examples are used throughout to demonstrate how these designs would be used in zoo research. © 1996 Wiley-Liss, Inc.     

Simulated beetle defoliation on willow genotypes in mixture and monotype plantations

The effect of simulated beetle damage (0%, 25%, 50% and 75% mechanical defoliation) on 12 willow genotypes, grown in short‐rotation coppice, was studied in a modified criss‐cross experimental design. The design enabled the above‐ground effects of monoculture and mixed planting to be assessed. Repeated measurements were modelled to produce derived variables in terms of time or, more appropriately, in terms of accumulated day length (i.e. ‘developmental time’) units. These derived variables were then analysed using the REsidual Maximum Likelihood (REML) method implemented in GenStat? (2001) . No significant competition effect between the genotypes due to planting regime was detected. Genotypes Salix viminalis × Salix schwerinii‘Beagle’ and S. viminalis × S. schwerinii‘Torhild’ were found to have the greatest rate of increase in leaves regardless of defoliation and also the greatest height prior to defoliation. Genotype Salix dasyclados‘Loden’ showed the highest rate of growth under the stress of defoliation. When assessing height at the end of the growing season, S. viminalis × S. schwerinii‘Olof’ was the highest genotype for 25% and 75% levels of defoliation, but genotypes Salix aurita × Salix cinerea‘Delamere’, Loden and S. viminalis × Salix burjatica‘Ashton Parfitt’ appeared to be most tolerant by having consecutively lower base day lengths (i.e. increasing the accumulation of developmental units and the length of the growing season) for increasing defoliation. Shorter genotypes tended to be more tolerant, but of the higher genotypes reaching a control height of greater than 3 m by the end of the growing season, S. viminalis × S. schwerinii‘Tora’ and Beagle performed best to 50% defoliation.     

Guidelines for measuring and reporting environmental conditions in controlled-environment studies

Guidelines for measuring and reporting environmental conditions in plant growth chambers are presented in tabular form. These guidelines are recommended by the North Central Region (NCR-101) Technical Committee on Growth Chamber Use, a committee formed under the Cooperative Research Program of the State Agricultural Experiment Stations (SAES) and the United States Department of Agriculture (USDA). Recommendations on location and frequency of measurements as well as suggested format and units of measurement are listed for each environmental parameter. The adoption of these standardized guidelines should greatly improve the uniformity of research conducted in controlled environments and facilitate comparison of experimental results obtained in studies conducted in different laboratories on a world-wide basis.     

法夫酵母产虾青素的反复分批及反复分批补料发酵

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