Adaptation to a latitudinal thermal gradient within a widespread copepod species:the contributions of genetic divergence and phenotypic plasticity

Understanding how populations adapt to heterogeneous thermal regimes is essential for comprehending how latitudinal gradients in species diversification are formed, and how taxa will respond to ongoing climate change. Adaptation can occur by innate genetic factors, by phenotypic plasticity, or by a combination of both mechanisms. Yet, the relative contribution of such mechanisms to large-scale latitudinal gradients of thermal tolerance across conspecific populations remains unclear. We examine thermal performance in 11 populations of the intertidal copepod Tigriopus californicus, ranging from Baja California Sur (Mexico) to British Columbia (Canada). Common garden experiments show that survivorship to acute heat-stress differs between populations (by up to 3.8°C in LD50 values), reflecting a strong genetic thermal adaptation. Using a split-brood experiment with two rearing temperatures, we also show that developmental phenotypic plasticity is beneficial to thermal tolerance (by up to 1.3°C), and that this effect differs across populations. Although genetic divergence in heat tolerance strongly correlates with latitude and temperature, differences in the plastic response do not. In the context of climate warming, our results confirm the general prediction that low-latitude populations are most susceptible to local extinction because genetic adaptation has placed physiological limits closer to current environmental maxima, but our results also contradict the prediction that phenotypic plasticity is constrained at lower latitudes

Stoichiometry and thickness dependence of superconducting properties of niobium nitride thin films

The current technology used in linear particle accelerators is based on superconducting radio frequency (SRF) cavities fabricated from bulk niobium (Nb), which have smaller surface resistance and therefore dissipate less energy than traditional nonsuperconducting copper cavities. Using bulk Nb for the cavities has several advantages, which are discussed elsewhere; however, such SRF cavities have a material-dependent accelerating gradient limit. In order to overcome this fundamental limit, a multilayered coating has been proposed using layers of insulating and superconducting material applied to the interior surface of the cavity. The key to this multilayered model is to use superconducting thin films to exploit the potential field enhancement when these films are thinner than their London penetration depth. Such field enhancement has been demonstrated in MgB2 thin films; here, the authors consider films of another type-II superconductor, niobium nitride (NbN). The authors present their work correlating stoichiometry and superconducting properties in NbN thin films and discuss the thickness dependence of their superconducting properties, which is important for their potential use in the proposed multilayer structure. While there are some previous studies on the relationship between stoichiometry and critical temperature T-C, the authors are the first to report on the correlation between stoichiometry and the lower critical field H-C1. (C) 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)

Complete replication of hepatitis C virus in cell culture.

Many aspects of the hepatitis C virus (HCV) life cycle have not been reproduced in cell culture, which has slowed research progress on this important human pathogen. Here, we describe a full-length HCV genome that replicates and produces virus particles that are infectious in cell culture (HCVcc). Replication of HCVcc was robust, producing nearly 10(5) infectious units per milliliter within 48 hours. Virus particles were filterable and neutralized with a monoclonal antibody against the viral glycoprotein E2. Viral entry was dependent on cellular expression of a putative HCV receptor, CD81. HCVcc replication was inhibited by interferon-alpha and by several HCV-specific antiviral compounds, suggesting that this in vitro system will aid in the search for improved antivirals

Highly trabeculated structure of the human endocardium underlies asymmetrical response to low-energy monophasic shocks

Novel low-energy defibrillation therapies are thought to be driven by virtual-electrodes (VEs), due to the interaction of applied monophasic electric shocks with fine-scale anatomical structures within the heart. Significant inter-species differences in the cardiac (micro)-anatomy exist, however, particularly with respect to the degree of endocardial trabeculations, which may underlie important differences in response to low-energy defibrillation protocols. Understanding the interaction of monophasic electric fields with the specific human micro-anatomy is therefore imperative in facilitating the translation and optimisation of these promising experimental therapies to the clinic. In this study, we sought to investigate how electric fields from implanted devices interact with the highly trabeculated human endocardial surface to better understand shock success in order to help optimise future clinical protocols. A bi-ventricular human computational model was constructed from high resolution (350 μm) ex-vivo MR data, including anatomically accurate endocardial structures. Monophasic shocks were applied between a basal right ventricular catheter and an exterior ground. Shocks of varying strengths were applied with both anodal [positive right ventricle (RV) electrode] and cathodal (negative RV electrode) polarities at different states of tissue refractoriness and during induced arrhythmias. Anodal shocks induced isolated positive VEs at the distal side of “detached” trabeculations, which rapidly spread into hyperpolarised tissue on the surrounding endocardial surfaces following the shock. Anodal shocks thus depolarised more tissue 10 ms after the shock than cathodal shocks where the propagation of activation from VEs induced on the proximal side of “detached” trabeculations was prevented due to refractory endocardium. Anodal shocks increased arrhythmia complexity more than cathodal shocks during failed anti-arrhythmia shocks. In conclusion, multiple detached trabeculations in the human ventricle interact with anodal stimuli to induce multiple secondary sources from VEs, facilitating more rapid shock-induced ventricular excitation compared to cathodal shocks. Such a mechanism may help explain inter-species differences in response to shocks and help to develop novel defibrillation strategies

Optimizing hatchery practices for genetic improvement of marine bivalves

This is the final version. Available from Wiley via the DOI in this record. Aquaculture currently accounts for approximately half of all seafood produced and is the fastest growing farmed food sector globally. Marine bivalve aquaculture, the farming of oysters, mussels and clams, represents a highly sustainable component of this industry and has major potential for global expansion via increased efficiency, and numbers of, production systems. Artificial spat propagation (i.e. settled juveniles) in hatcheries and selective breeding have the potential to offer rapid and widespread gains for molluscan aquaculture industry. However, bivalves have unique life-histories, genetic and genomic characteristics, which present significant challenges to achieving such genetic improvement. Selection pressures experienced by bivalve larvae and spat in the wild contribute to drive population structure and animal fitness. Similarly, domestication selection is likely to act on hatchery-produced spat, the full implications of which have not been fully explored. In this review, we outline the key features of these taxa and production practices applied in bivalve aquaculture, which have the potential to affect the genetic and phenotypic variability of hatchery-propagated stock. Alongside, we compare artificial and natural processes experienced by bivalves to investigate the possible consequences of hatchery propagation on stock production. In addition, we identify key areas of investigation that need to be prioritized to continue to the advancement of bivalve genetic improvement via selective breeding. The growing accessibility of next-generation sequencing technology and high-powered computational capabilities facilitate the implementation of novel genomic tools in breeding programmes of aquatic species. These emerging techniques represent an exciting opportunity for sustainably expanding the bivalve aquaculture sector.Biotechnology & Biological Sciences Research Council (BBSRC)Natural Environment Research CouncilBiotechnology and Biological Sciences Research CouncilBiotechnology and Biological Sciences Research CouncilBiotechnology and Biological Sciences Research Counci

First impressions from faces in dynamic approach–avoidance contexts

Theoretical understanding of first impressions from faces has been closely associated with the proposal that rapid approach–avoidance decisions are needed during social interactions. Nevertheless, experimental work has rarely examined first impressions of people who are actually moving—instead extrapolating from photographic images. In six experiments, we describe the relationship between social attributions (dominance and trustworthiness) and the motion and apparent intent of a perceived person. We first show strong correspondence between judgments of photos and avatars of the same people (Experiment 1). Avatars were rated as more dominant and trustworthy when walking toward the viewer than when stationary (Experiment 2). Furthermore, avatars approaching the viewer were rated as more dominant than those avoiding (walking past) the viewer, or remaining stationary (Experiment 3). Trustworthiness was increased by movement, but not affected by approaching/avoiding paths. Surprisingly, dominance ratings increased both when avatars were approaching and being approached (Experiments 4–6), independently of agency. However, diverging movement (moving backward) reduced dominance ratings—again independently of agency (Experiment 6). These results demonstrate the close link between dominance judgments and approach and show the updatable nature of first impressions—their formation depended on the immediate dynamic context in a more subtle manner than previously suggested

Estimating Household and Community Transmission of Ocular Chlamydia trachomatis

Trachoma is a major cause of blindness worldwide and results from ocular infection with the bacterium Chlamydia trachomatis. Mass distribution of antibiotics in communities is part of the strategy to eliminate blindness due to trachoma. Targeted treatment of infected households could be more efficient, but the success of such a strategy will depend on the extent of transmission of infection between members of the same household and between members of the community. In this work, we estimated the magnitude of household and community transmission in four populations, two from The Gambia and two from Tanzania. We found that, in general, transmission of the bacteria within households is very efficient. In three of the four populations, persistent infection within households was predicted by the high level of household transmission (a phenomenon observed in longitudinal studies of trachoma). In all of the studied populations, individuals who live in households with more individuals contribute more to the number of new infections in the community than those who live with fewer individuals. Further studies are required to identify and examine household-targeted approaches to treatment

Clearing the Backlog: Trichiasis Surgeon Retention and Productivity in Northern Ethiopia

Blindness from trachoma is caused by the abrasive effect of trichiasis (in-turned eyelashes). Surgery is performed to correct this anatomical abnormality, and prevent blindness. Despite the progress made in many regions in controlling the active/infectious stages of this disease, the global prevalence of trichiasis remains about the same. Current surgical activity is barely keeping abreast of incident trichiasis; this is undermining all the other efforts to control trachoma. We examine staff retention and productivity in Amhara Region, Ethiopia, where many hundreds of health care workers have been trained to perform the surgery. We found that the majority of people trained to do the surgery are now not in a position to do so. Amongst the sub-set that is still active within the programme, surgical productivity is low, with most surgery performed during “outreach campaigns” Insufficient surgical instruments and consumables were frequent problems. Strengthened health-systems management can overcome many of the problems that are holding back the delivery of an effective trichiasis surgical service