Decision-Making in Research Tasks with Sequential Testing

Background: In a recent controversial essay, published by JPA Ioannidis in PLoS Medicine, it has been argued that in some research fields, most of the published findings are false. Based on theoretical reasoning it can be shown that small effect sizes, error-prone tests, low priors of the tested hypotheses and biases in the evaluation and publication of research findings increase the fraction of false positives. These findings raise concerns about the reliability of research. However, they are based on a very simple scenario of scientific research, where single tests are used to evaluate independent hypotheses. Methodology/Principal Findings: In this study, we present computer simulations and experimental approaches for analyzing more realistic scenarios. In these scenarios, research tasks are solved sequentially, i.e. subsequent tests can be chosen depending on previous results. We investigate simple sequential testing and scenarios where only a selected subset of results can be published and used for future rounds of test choice. Results from computer simulations indicate that for the tasks analyzed in this study, the fraction of false among the positive findings declines over several rounds of testing if the most informative tests are performed. Our experiments show that human subjects frequently perform the most informative tests, leading to a decline of false positives as expected from the simulations. Conclusions/Significance: For the research tasks studied here, findings tend to become more reliable over time. We also find that the performance in those experimental settings where not all performed tests could be published turned out to be surprisingly inefficient. Our results may help optimize existing procedures used in the practice of scientific research and provide guidance for the development of novel forms of scholarly communication.Engineering and Applied SciencesPsycholog

A survey of current mammal rehabilitation and release practices

Mammal rehabilitation is carried out in hundreds of centres worldwide, requiring a large investment of time, personnel and funds. Although there are numerous published studies focusing on post-release outcomes, few have discussed the methods employed in rehabilitation. As an important first step toward addressing this, data were collected directly from rehabilitation centres about their aims, methods employed and assessment of outcomes. A survey of mammal rehabilitation centres was conducted with data collected in the form of responses to multiple-choice questions and written responses. Our results indicated a number of challenges, including: problems surrounding social group formation, lack of predator avoidance training, limited or no pre-release medical screening, release of animals exhibiting stereotypic behaviours, frequently short-term (<6 months) post-release monitoring, with only a third of centres assessing the success of releases. Although many factors may influence the success of rehabilitation, improvements to monitoring and assessment are needed before the effects of any changes to protocols could be determined. Extended post-release monitoring and thorough assessment should be a part of any future mammal rehabilitation projects. With a view to improving the rehabilitation phase, we have developed a decision tree to assist the assessment of mammals at each stage of the rehabilitation process. This could be easily adapted to create detailed species-specific models in the future

Does fluctuating asymmetry of hind legs impose costs on escape speed in house crickets (Acheta domesticus)?

Fluctuating asymmetry (FA) is often thought to be an indicator of developmental stability—an individual’s ability to resist environmental and genetic stress during development—and thus demonstrates phenotypic quality. Research on the influence of FA on locomotion has often found that high FA in legs and wings impedes locomotor performance. Crickets rely on their six limbs to flee from predators and parasitoids. Hind legs are of particular importance during escape as they contribute to running speed. FA research overwhelmingly focuses on its impact on sexual selection, with little on locomotion and only one study of the impact of FA on invertebrate locomotion. Here, we examined the effect of FA in hind legs on the escape speed of house crickets (Acheta domesticus) and the locomotor costs of hind limb autotomy. Unexpectedly, our findings indicate that FA of hind legs have no influence on the escape speed of either male or female A. domesticus. This is inconsistent with most research conducted on FA and vertebrate locomotion that indicates FA negatively impacts locomotion, but is consistent with the only research examining FA and invertebrate locomotion. Our other findings were more congruent with the literature on other Orthoptera, as body size was found to have an influence on the escape speeds of intact females and those that lost two hind limbs. Whilst our results indicate that FA did not influence locomotion, this may not be the case for other invertebrate taxa where variation in FA may have an important role in natural selection

Determinants of inter-specific variation in basal metabolic rate

Basal metabolic rate (BMR) is the rate of metabolism of a resting, postabsorptive, non-reproductive, adult bird or mammal, measured during the inactive circadian phase at a thermoneutral temperature. BMR is one of the most widely measured physiological traits, and data are available for over 1,200 species. With data available for such a wide range of species, BMR is a benchmark measurement in ecological and evolutionary physiology, and is often used as a reference against which other levels of metabolism are compared. Implicit in such comparisons is the assumption that BMR is invariant for a given species and that it therefore represents a stable point of comparison. However, BMR shows substantial variation between individuals, populations and species. Investigation of the ultimate (evolutionary) explanations for these differences remains an active area of inquiry, and explanation of size-related trends remains a contentious area. Whereas explanations for the scaling of BMR are generally mechanistic and claim ties to the first principles of chemistry and physics, investigations of mass-independent variation typically take an evolutionary perspective and have demonstrated that BMR is ultimately linked with a range of extrinsic variables including diet, habitat temperature, and net primary productivity. Here we review explanations for size-related and mass-independent variation in the BMR of animals, and suggest ways that the various explanations can be evaluated and integrated