A program for the computation of power and determination of sample size in hierarchical experimental designs.

We have devised a program that allows computation of the power of F-test, and hence determination of appropriate sample and subsample sizes, in the context of the one-way hierarchical analysis of variance with fixed effects. The power at a fixed alternative is an increasing function of the sample size and of the subsample size. The program makes it easy to obtain the power of F-test for a range of values of sample and subsample sizes, and therefore the appropriate sizes based on a desired power. The program can be used for the 'ordinary' case of the one-way analysis of variance, as well as for hierarchical analysis of variance with two stages of sampling. Examples are given of the practical use of the program.

Accuracy of indirect estimation of power output from uphill performance in cycling.

PURPOSE: To use measurement by cycling power meters (Pmes) to evaluate the accuracy of commonly used models for estimating uphill cycling power (Pest). Experiments were designed to explore the influence of wind speed and steepness of climb on accuracy of Pest. The authors hypothesized that the random error in Pest would be largely influenced by the windy conditions, the bias would be diminished in steeper climbs, and windy conditions would induce larger bias in Pest. METHODS: Sixteen well-trained cyclists performed 15 uphill-cycling trials (range: length 1.3-6.3 km, slope 4.4-10.7%) in a random order. Trials included different riding position in a group (lead or follow) and different wind speeds. Pmes was quantified using a power meter, and Pest was calculated with a methodology used by journalists reporting on the Tour de France. RESULTS: Overall, the difference between Pmes and Pest was -0.95% (95%CI: -10.4%, +8.5%) for all trials and 0.24% (-6.1%, +6.6%) in conditions without wind (<2 m/s). The relationship between percent slope and the error between Pest and Pmes were considered trivial. CONCLUSIONS: Aerodynamic drag (affected by wind velocity and orientation, frontal area, drafting, and speed) is the most confounding factor. The mean estimated values are close to the power-output values measured by power meters, but the random error is between ±6% and ±10%. Moreover, at the power outputs (>400 W) produced by professional riders, this error is likely to be higher. This observation calls into question the validity of releasing individual values without reporting the range of random errors.

The branch-site test of positive selection is surprisingly robust but lacks power under synonymous substitution saturation and variation in GC

Positive selection is widely estimated from protein coding sequence alignments by the nonsynonymous-to-synonymous ratio omega. Increasingly elaborate codon models are used in a likelihood framework for this estimation. Although there is widespread concern about the robustness of the estimation of the omega ratio, more efforts are needed to estimate this robustness, especially in the context of complex models. Here, we focused on the branch-site codon model. We investigated its robustness on a large set of simulated data. First, we investigated the impact of sequence divergence. We found evidence of underestimation of the synonymous substitution rate for values as small as 0.5, with a slight increase in false positives for the branch-site test. When dS increases further, underestimation of dS is worse, but false positives decrease. Interestingly, the detection of true positives follows a similar distribution, with a maximum for intermediary values of dS. Thus, high dS is more of a concern for a loss of power (false negatives) than for false positives of the test. Second, we investigated the impact of GC content. We showed that there is no significant difference of false positives between high GC (up to similar to 80%) and low GC (similar to 30%) genes. Moreover, neither shifts of GC content on a specific branch nor major shifts in GC along the gene sequence generate many false positives. Our results confirm that the branch-site is a very conservative test.

Effects of Three Types of Exercise Interventions on Healthy Old Adults' Gait Speed : A Systematic Review and Meta-Analysis.

BACKGROUND: Habitual walking speed predicts many clinical conditions later in life, but it declines with age. However, which particular exercise intervention can minimize the age-related gait speed loss is unclear. PURPOSE: Our objective was to determine the effects of strength, power, coordination, and multimodal exercise training on healthy old adults' habitual and fast gait speed. METHODS: We performed a computerized systematic literature search in PubMed and Web of Knowledge from January 1984 up to December 2014. Search terms included 'Resistance training', 'power training', 'coordination training', 'multimodal training', and 'gait speed (outcome term). Inclusion criteria were articles available in full text, publication period over past 30 years, human species, journal articles, clinical trials, randomized controlled trials, English as publication language, and subject age ≥65 years. The methodological quality of all eligible intervention studies was assessed using the Physiotherapy Evidence Database (PEDro) scale. We computed weighted average standardized mean differences of the intervention-induced adaptations in gait speed using a random-effects model and tested for overall and individual intervention effects relative to no-exercise controls. RESULTS: A total of 42 studies (mean PEDro score of 5.0 ± 1.2) were included in the analyses (2495 healthy old adults; age 74.2 years [64.4-82.7]; body mass 69.9 ± 4.9 kg, height 1.64 ± 0.05 m, body mass index 26.4 ± 1.9 kg/m(2), and gait speed 1.22 ± 0.18 m/s). The search identified only one power training study, therefore the subsequent analyses focused only on the effects of resistance, coordination, and multimodal training on gait speed. The three types of intervention improved gait speed in the three experimental groups combined (n = 1297) by 0.10 m/s (±0.12) or 8.4 % (±9.7), with a large effect size (ES) of 0.84. Resistance (24 studies; n = 613; 0.11 m/s; 9.3 %; ES: 0.84), coordination (eight studies, n = 198; 0.09 m/s; 7.6 %; ES: 0.76), and multimodal training (19 studies; n = 486; 0.09 m/s; 8.4 %, ES: 0.86) increased gait speed statistically and similarly. CONCLUSIONS: Commonly used exercise interventions can functionally and clinically increase habitual and fast gait speed and help slow the loss of gait speed or delay its onset.

A rationalist perspective on the autonomy of international sport governing bodies : towards a pragmatic autonomy in the steering of sports

International sport governing bodies (ISGBs) are built on the foundations of freedom of association and traditionally enjoy a large degree of autonomy in their decision-making. Their autonomy is increasingly confined, however, and their hierarchical self-governance is giving way to a more networked governance, in which different stakeholders exert power in different ways and in different contexts in a complex web of interrelationships. Taking a rationalist perspective on the autonomy of ISGBs, this article demonstrates that ISGBs are deploying strategies to safeguard their waning governing monopoly over international sport. Opting for an inductive approach, the authors present four possible conceptualizations of autonomy as applied to ISGBs, namely political autonomy, legal autonomy, financial autonomy and pyramidal autonomy. For each dimension, they describe the different strategies ISGBs wield in order to safeguard different dimensions of their autonomy. This article uses governance theories to hypothesize that the autonomy of ISGBs can be understood as 'pragmatic autonomy' since ISGBs only cede certain aspects of their autonomy under particular circumstances and when being subject to specific threats. Acting in a rationalist manner, they are able to keep control over governance developments in sport by using indirect and more subtle forms of governance.

Death caused by cardioinhibitory reflex cardiac arrest--a systematic review of cases.

Forensic pathologists often refer to the cardioinhibitory reflex cardiac arrest (CiRCA) following short neck trauma as a mechanism of death. We sought via a systematic review of the literature to identify circumstances under which carotid bifurcation stimulation could lead to death. Two independent reviewers selected case studies or reports from Medline, ISI Web of Knowledge, and Embase. Circumstances and contributory factors were extracted for each case. From the available data, authors independently assessed whether CiRCA was highly probable (no alternative explanation possible), probable (alternative explanation possible), or unlikely (alternative explanation highly probable). A narrative approach was used to define circumstances in which CiRCA remained possible. From the 48 published cases evoking CiRCA as a possible cause of death between 1881 and 2009, 28 were most likely to result of other mechanism of death (i.e., cerebral hypoxia due to carotid compression, mechanical asphyxia, myocardial infarction). CiRCA remained possible for 20 cases (including five based on anecdotal evidence only) with only one case with no alternative explanation other than CiRCA. Our findings support the presumption that reflex cardiac arrhythmia due to carotid bifurcation stimulation cannot provoke death alone. Actual state of knowledge suggests CiRCA might be contributory to death in the presence of drug abuse and/or cardiac pathology, often associated with physical and/or mental excitation.

Detecting epistasis with restricted response patterns in pairs of biallelic loci.

Well-established examples of genetic epistasis between a pair of loci typically show characteristic patterns of phenotypic distributions in joint genotype tables. However, inferring epistasis given such data is difficult due to the lack of power in commonly used approaches, which decompose the epistatic patterns into main plus interaction effects followed by testing the interaction term. Testing additive-only or all terms may have more power, but they are sensitive to nonepistatic patterns. Alternatively, the epistatic patterns of interest can be enumerated and the best matching one is found by searching through the possibilities. Although this approach requires multiple testing correction over possible patterns, each pattern can be fitted with a regression model with just one degree of freedom and thus the overall power can still be high, if the number of possible patterns is limited. Here we compare the power of the linear decomposition and pattern search methods, by applying them to simulated data generated under several patterns of joint genotype effects with simple biological interpretations. Interaction-only tests are the least powerful; while pattern search approach is the most powerful if the range of possibilities is restricted, but still includes the true pattern.

Interpersonal Power: A Review, Critique, and Research Agenda

Power is a fundamental force in social relationships and is pervasive throughout various types of interactions. Although research has shown that the possession of power can change the powerholder, the full extent of power's consequences on individuals' decision making capabilities and social interactions within organizations is not fully understood. The goal of this paper is to review, synthesize, and critique the literature on power with a focus on its organizational and managerial implications. Specifically, we propose a definition of power that takes into account its three defining characteristics-having the discretion and means to enforce one's will-and summarize the extant literature on how power influences individuals' thoughts, emotions, and actions both in terms of prosocial and antisocial outcomes. In addition, we highlight important moderators of power and describe ways in which it can be studied in a more rigorous manner by examining methodological issues and pitfalls with regard to its measurement and manipulation. We also provide future research directions to motivate and guide the study of power by management scholars. Our desire is to present a thorough and parsimonious account of power's influence on individuals within an organizational context, as well as provide a foundation that scholars can build upon as they continue to make consequential contributions to the study of power.