Circadian rhythms enable efficient resource selection in a human‐modified landscape

Animals access resources such as food and shelter, and acquiring these resources has varying risks and benefits, depending on the suitability of the landscape. Some animals change their patterns of resource selection in space and time to optimize the trade‐off between risks and benefits. We examine the circadian variation in resource selection of swamp wallabies (Wallabia bicolor) within a human‐modified landscape, an environment of varying suitability. We used GPS data from 48 swamp wallabies to compare the use of landscape features such as woodland and scrub, housing estates, farmland, coastal areas, wetlands, waterbodies, and roads to their availability using generalized linear mixed models. We investigated which features were selected by wallabies and determined whether the distance to different landscape features changed, depending on the time of the day. During the day, wallabies were more likely to be found within or near natural landscape features such as woodlands and scrub, wetlands, and coastal vegetation, while avoiding landscape features that may be perceived as more risky (roads, housing, waterbodies, and farmland), but those features were selected more at night. Finally, we mapped our results to predict habitat suitability for swamp wallabies in human‐modified landscapes. We showed that wallabies living in a human‐modified landscape selected different landscape features during day or night. Changing circadian patterns of resource selection might enhance the persistence of species in landscapes where resources are fragmented and disturbed.     

The role of ascorbate in antioxidant protection of biomembranes: Interaction with vitamin E and coenzyme Q

One of the vital roles of ascorbic acid (vitamin C) is to act as an antioxidant to protect cellular components from free radical damage. Ascorbic acid has been shown to scavenge free radicals directly in the aqueous phases of cells and the circulatory system. Ascorbic acid has also been proven to protect membrane and other hydrophobic compartments from such damage by regenerating the antioxidant form of vitamin E. In addition, reduced coenzyme Q, also a resident of hydrophobic compartments, interacts with vitamin E to regenerate its antioxidant form. The mechanism of vitamin C antioxidant function, the myriad of pathologies resulting from its clinical deficiency, and the many health benefits it provides, are reviewed.     

SEXUAL SELECTION ACCELERATES THE ELIMINATION OF A DELETERIOUS MUTANT IN DROSOPHILA MELANOGASTER

Although theory indicates that indirect genetic benefits through mate choice should be widespread, empirical work has often either failed to detect the operation of such benefits or shown a net cost to the presence of sexual selection. We tested whether sexual selection can increase the speed with which a conditionally deleterious allele is removed from a laboratory population of Drosophila melanogaster. The alcohol dehydrogenase null allele ( Adh –) confers slightly lower viability than wild-type alleles in the absence of ethanol but is lethal in homozygotes when ethanol comprises 6% of the medium. We tracked the frequency of this allele in artificially constructed populations reared at three different levels of ethanol (0%, 2%, and 4%) that either experienced sexual selection or did not. Loss of the deleterious Adh – allele was more rapid when sexual selection was allowed to act, especially in the presence of ethanol. We also quantified the strength of both nonsexual and sexual selection against the Adh – allele using maximum-likelihood estimation. In contrast to recent experiments employing monogamy/polygamy designs, our results demonstrate a fitness benefit to sexual selection. This is consistent with the operation of good-genes female choice.     

Risk knowledge,product knowledge,and brand benefits for purchase intentions: Experiences with air purifiers against city smog in China

The present study is based on the theoretical framework of protective action decision model. This study aims to explain the relationship among the risk knowledge, product knowledge, risk perception, and brand benefits and the consumers’ purchase intentions of a specific air purifier compared with alternative brands. The research context is city smog. Results show that consumers’ risk knowledge and product knowledge significantly affect their purchase of an air purifier brand as well as play a considerable role in predicting their risk perception and in foreseeing their purchase intentions under the influence of the manufacturer's advertising strategies. Furthermore, consumers’ risk perception is a critical psychological factor that has a significantly positive influence on brand's experiential benefits, instead of functional and symbolic benefits. In particular, when comparing with brand's functional and symbolic benefits, the brand's experiential benefits is more attractive to consumers and has a stronger effect on consumers’ air purifier purchase intentions in the context of city smog.     

A failure in solidarity: Ethical challenges in the development and implementation of new tuberculosis technologies

Prominent tuberculosis (TB) actors are invoking solidarity to motivate and justify collective action to address TB, including through intensified development and implementation (D&I) of technologies such as drugs and diagnostics. We characterize the ethical challenges associated with D&I of new TB technologies by drawing on stakeholder perspectives from 23 key informant interviews and we articulate the ethical implications of solidarity for TB technology D&I. The fundamental ethical issue facing TB technological D&I is a failure within and beyond the TB community to stand in solidarity with persons with TB in addressing the complex sociopolitical contexts of technological D&I. The failure in solidarity relates to two further ethical challenges raised by respondents: skewed power dynamics that hinder D&I and uncertainties around weighing risks and benefits associated with new technologies. Respondents identified advocacy and participatory research practices as necessary to address such challenges and to motivate sustained collective action to accelerate toward TB elimination. We present the first empirical examination of bioethical accounts of solidarity in public and global health. Our study suggests that solidarity allows us better to understand and address the ethical challenges that arrest the D&I of new TB technologies. Solidarity lends credence to policies and practices that address the relational nature of illness and health through collective action.     

Polyandrous females produce sons that are successful at post‐copulatory competition

Some of the genetic benefit hypotheses put forward to explain multiple male mating (polyandry) predict that sons of polyandrous females will have an increased competitive ability under precopulatory or post‐copulatory competition via paternally inherited traits, such as attractiveness or fertilization efficiency. Here, we tested these predictions by comparing the competitive ability of sons of experimentally monandrous and polyandrous female bank voles (Myodes glareolus), while controlling for potential material and maternal effects. In female choice experiments, we found no clear preference for sons of either monandrous or polyandrous mothers. Moreover, neither male type was dominant over the other, indicating no advantage in precopulatory male contest competition. However, in competitive matings, sons of polyandrous mothers significantly increased their mating efforts (mating duration, intromission number). In line with this, paternity success was biased towards sons of polyandrous mothers. Because there was no evidence for maternal effects, our results suggest that female bank voles gain genetic benefits from polyandry.     

Variance Calculations for Direct Adjusted Survival Curves,with Applications to Testing for No Treatment Effect

Several investigators have recently constructed survival curves adjusted for imbalances in prognostic factors by a method which we call direct adjustment. We present methods for calculating variances of these direct adjusted survival curves and their differences. Estimates of the adjusted curves, their variances, and the variances of their differences are compared for non-parametric (Kaplan-Meier), semi-parametric (Cox) and parametric (Weibull) models applied to censored exponential data. Semi-parametric proportional hazards models were nearly fully efficient for estimating differences in adjusted curves, but parametric estimates of individual adjusted curves may be substantially more precise. Standardized differences between direct adjusted survival curves may be used to test the null hypothesis of no treatment effect. This procedure may prove especially useful when the proportional hazards assumption is questionable.