Social density, but not sex ratio, drives ecdysteroid hormone provisioning to eggs by female house crickets (Acheta domesticus)

Social environment profoundly influences the fitness of animals, affecting their probability of survival to adulthood, longevity, and reproductive output. The social conditions experienced by parents at the time of reproduction can predict the social environments that offspring will face. Despite clear challenges in predicting future environmental conditions, adaptive maternal effects provide a mechanism of passing environmental information from parent to offspring and are now considered pervasive in natural systems. Maternal effects have been widely studied in vertebrates, especially in the context of social environment, and are often mediated by steroid hormone (SH) deposition to eggs. In insects, although many species dramatically alter phenotype and life‐history traits in response to social density, the mechanisms of these alterations, and the role of hormone deposition by insect mothers into their eggs, remains unknown. In the experiments described here, we assess the effects of social environment on maternal hormone deposition to eggs in house crickets (Acheta domesticus). Specifically, we tested the hypotheses that variable deposition of ecdysteroid hormones (ESH) to eggs is affected by both maternal (a) social density and (b) social composition. We found that while maternal hormone deposition to eggs does not respond to social composition (sex ratio), it does reflect social density; females provision their eggs with higher ESH doses under low‐density conditions. This finding is consistent with the interpretation that variable ESH provisioning is an adaptive maternal response to social environment and congruent with similar patterns of variable maternal provisioning across the tree of life. Moreover, our results confirm that maternal hormone provisioning may mediate delayed density dependence by introducing a time lag in the response of offspring phenotype to population size.Here we show that female crickets respond to social density in provisioning their eggs with hormones that govern hatchling growth and development. This is the first evidence that we are aware of for hormone provisioning as a mechanism for achieving delayed density dependence in a population.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146319/1/ece34502_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146319/2/ece34502.pd

A systematic variation of the stellar initial mass function in early-type galaxies

Much of our knowledge of galaxies comes from analysing the radiation emitted by their stars. It depends on the stellar initial mass function (IMF) describing the distribution of stellar masses when the population formed. Consequently knowledge of the IMF is critical to virtually every aspect of galaxy evolution. More than half a century after the first IMF determination, no consensus has emerged on whether it is universal in different galaxies. Previous studies indicated that the IMF and the dark matter fraction in galaxy centres cannot be both universal, but they could not break the degeneracy between the two effects. Only recently indications were found that massive elliptical galaxies may not have the same IMF as our Milky Way. Here we report unambiguous evidence for a strong systematic variation of the IMF in early-type galaxies as a function of their stellar mass-to-light ratio, producing differences up to a factor of three in mass. This was inferred from detailed dynamical models of the two-dimensional stellar kinematics for the large Atlas3D representative sample of nearby early-type galaxies spanning two orders of magnitude in stellar mass. Our finding indicates that the IMF depends intimately on a galaxy's formation history.Comment: 4 pages, 2 figures, LaTeX. Accepted for publication as a Nature Letter. More information about our Atlas3D project is available at http://purl.org/atlas3

The effect of a brief social intervention on the examination results of UK medical students: a cluster randomised controlled trial

Background: Ethnic minority (EM) medical students and doctors underperform academically, but little evidence exists on how to ameliorate the problem. Psychologists Cohen et al. recently demonstrated that a written self-affirmation intervention substantially improved EM adolescents' school grades several months later. Cohen et al.'s methods were replicated in the different setting of UK undergraduate medical education.Methods: All 348 Year 3 white (W) and EM students at one UK medical school were randomly allocated to an intervention condition (writing about one's own values) or a control condition (writing about another's values), via their tutor group. Students and assessors were blind to the existence of the study. Group comparisons on post-intervention written and OSCE (clinical) assessment scores adjusted for baseline written assessment scores were made using two-way analysis of covariance. All assessment scores were transformed to z-scores (mean = 0 standard deviation = 1) for ease of comparison. Comparisons between types of words used in essays were calculated using t-tests. The study was covered by University Ethics Committee guidelines.Results: Groups were statistically identical at baseline on demographic and psychological factors, and analysis was by intention to treat [intervention group EM n = 95, W n = 79; control group EM n = 77; W n = 84]. As predicted, there was a significant ethnicity by intervention interaction [F(4,334) = 5.74; p = 0.017] on the written assessment. Unexpectedly, this was due to decreased scores in the W intervention group [mean difference = 0.283; (95% CI = 0.093 to 0.474] not improved EM intervention group scores [mean difference = -0.060 (95% CI = -0.268 to 0.148)]. On the OSCE, both W and EM intervention groups outperformed controls [mean difference = 0.261; (95% CI = -0.047 to -0.476; p = 0.013)]. The intervention group used more optimistic words (p < 0.001) and more "I" and "self" pronouns in their essays (p < 0.001), whereas the control group used more "other" pronouns (p < 0.001) and more negations (p < 0.001).Discussion: Cohen et al.'s finding that a brief self-affirmation task narrowed the ethnic academic achievement gap was replicated on the written assessment but against expectations, this was due to reduced performance in the W group. On the OSCE, the intervention improved performance in both W and EM groups. In the intervention condition, participants tended to write about themselves and used more optimistic words than in the control group, indicating the task was completed as requested. The study shows that minimal interventions can have substantial educational outcomes several months later, which has implications for the multitude of seemingly trivial changes in teaching that are made on an everyday basis, whose consequences are never formally assessed

The Atlas3D project -- XIII. Mass and morphology of HI in early-type galaxies as a function of environment

We present the Atlas3D HI survey of 166 nearby early-type galaxies (ETGs) down to M(HI)~10^7 M_sun. We detect HI in ~40% of all ETGs outside the Virgo cluster and in ~10% of all ETGs inside it. This demonstrates that it is common for non-cluster ETGs to host HI. The HI morphology varies from regular discs/rings (the majority of the detections) to unsettled gas distributions. The former are either small discs (M(HI)<10^8 M_sun) confined within the stellar body and sharing the same kinematics of the stars, or large discs/rings (M(HI) up to 5x10^9 M_sun) extending to tens of kpc from the host galaxy and frequently kinematically decoupled from the stars. Neutral hydrogen provides material for star formation in ETGs. Galaxies with central HI exhibit signatures of star formation in ~70% of the cases, ~5 times more frequently than galaxies without central HI. The central ISM is dominated by molecular gas. In ETGs with a small gas disc the conversion of HI into H_2 is as efficient as in spirals. The ETG HI mass function has M*~2x10^9 M_sun and slope=-0.7. ETGs host much less HI than spirals as a family. However, a significant fraction of them is as HI-rich as spirals. The main difference between ETGs and spirals is that the former lack the high-column-density HI typical of the bright stellar disc of the latter. We find an envelope of decreasing M(HI) with increasing environment density. The gas-richest ETGs live in the poorest environments (where star-formation is more common), galaxies in the centre of Virgo have the lowest HI content, and the cluster outskirts are a transition region. We find an HI morphology-density relation. At low environment density HI is mostly distributed on large discs/rings. More disturbed HI morphologies dominate environment densities typical of rich groups, confirming the importance of processes occurring on a galaxy-group scale for the evolution of ETGs.Comment: Accepted for publication on MNRA

Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK.

BACKGROUND: A safe and efficacious vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), if deployed with high coverage, could contribute to the control of the COVID-19 pandemic. We evaluated the safety and efficacy of the ChAdOx1 nCoV-19 vaccine in a pooled interim analysis of four trials. METHODS: This analysis includes data from four ongoing blinded, randomised, controlled trials done across the UK, Brazil, and South Africa. Participants aged 18 years and older were randomly assigned (1:1) to ChAdOx1 nCoV-19 vaccine or control (meningococcal group A, C, W, and Y conjugate vaccine or saline). Participants in the ChAdOx1 nCoV-19 group received two doses containing 5 × 1010 viral particles (standard dose; SD/SD cohort); a subset in the UK trial received a half dose as their first dose (low dose) and a standard dose as their second dose (LD/SD cohort). The primary efficacy analysis included symptomatic COVID-19 in seronegative participants with a nucleic acid amplification test-positive swab more than 14 days after a second dose of vaccine. Participants were analysed according to treatment received, with data cutoff on Nov 4, 2020. Vaccine efficacy was calculated as 1 - relative risk derived from a robust Poisson regression model adjusted for age. Studies are registered at ISRCTN89951424 and ClinicalTrials.gov, NCT04324606, NCT04400838, and NCT04444674. FINDINGS: Between April 23 and Nov 4, 2020, 23 848 participants were enrolled and 11 636 participants (7548 in the UK, 4088 in Brazil) were included in the interim primary efficacy analysis. In participants who received two standard doses, vaccine efficacy was 62·1% (95% CI 41·0-75·7; 27 [0·6%] of 4440 in the ChAdOx1 nCoV-19 group vs71 [1·6%] of 4455 in the control group) and in participants who received a low dose followed by a standard dose, efficacy was 90·0% (67·4-97·0; three [0·2%] of 1367 vs 30 [2·2%] of 1374; pinteraction=0·010). Overall vaccine efficacy across both groups was 70·4% (95·8% CI 54·8-80·6; 30 [0·5%] of 5807 vs 101 [1·7%] of 5829). From 21 days after the first dose, there were ten cases hospitalised for COVID-19, all in the control arm; two were classified as severe COVID-19, including one death. There were 74 341 person-months of safety follow-up (median 3·4 months, IQR 1·3-4·8): 175 severe adverse events occurred in 168 participants, 84 events in the ChAdOx1 nCoV-19 group and 91 in the control group. Three events were classified as possibly related to a vaccine: one in the ChAdOx1 nCoV-19 group, one in the control group, and one in a participant who remains masked to group allocation. INTERPRETATION: ChAdOx1 nCoV-19 has an acceptable safety profile and has been found to be efficacious against symptomatic COVID-19 in this interim analysis of ongoing clinical trials. FUNDING: UK Research and Innovation, National Institutes for Health Research (NIHR), Coalition for Epidemic Preparedness Innovations, Bill & Melinda Gates Foundation, Lemann Foundation, Rede D'Or, Brava and Telles Foundation, NIHR Oxford Biomedical Research Centre, Thames Valley and South Midland's NIHR Clinical Research Network, and AstraZeneca

Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK

Background A safe and efficacious vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), if deployed with high coverage, could contribute to the control of the COVID-19 pandemic. We evaluated the safety and efficacy of the ChAdOx1 nCoV-19 vaccine in a pooled interim analysis of four trials. Methods This analysis includes data from four ongoing blinded, randomised, controlled trials done across the UK, Brazil, and South Africa. Participants aged 18 years and older were randomly assigned (1:1) to ChAdOx1 nCoV-19 vaccine or control (meningococcal group A, C, W, and Y conjugate vaccine or saline). Participants in the ChAdOx1 nCoV-19 group received two doses containing 5 × 1010 viral particles (standard dose; SD/SD cohort); a subset in the UK trial received a half dose as their first dose (low dose) and a standard dose as their second dose (LD/SD cohort). The primary efficacy analysis included symptomatic COVID-19 in seronegative participants with a nucleic acid amplification test-positive swab more than 14 days after a second dose of vaccine. Participants were analysed according to treatment received, with data cutoff on Nov 4, 2020. Vaccine efficacy was calculated as 1 - relative risk derived from a robust Poisson regression model adjusted for age. Studies are registered at ISRCTN89951424 and ClinicalTrials.gov, NCT04324606, NCT04400838, and NCT04444674. Findings Between April 23 and Nov 4, 2020, 23 848 participants were enrolled and 11 636 participants (7548 in the UK, 4088 in Brazil) were included in the interim primary efficacy analysis. In participants who received two standard doses, vaccine efficacy was 62·1% (95% CI 41·0–75·7; 27 [0·6%] of 4440 in the ChAdOx1 nCoV-19 group vs71 [1·6%] of 4455 in the control group) and in participants who received a low dose followed by a standard dose, efficacy was 90·0% (67·4–97·0; three [0·2%] of 1367 vs 30 [2·2%] of 1374; pinteraction=0·010). Overall vaccine efficacy across both groups was 70·4% (95·8% CI 54·8–80·6; 30 [0·5%] of 5807 vs 101 [1·7%] of 5829). From 21 days after the first dose, there were ten cases hospitalised for COVID-19, all in the control arm; two were classified as severe COVID-19, including one death. There were 74 341 person-months of safety follow-up (median 3·4 months, IQR 1·3–4·8): 175 severe adverse events occurred in 168 participants, 84 events in the ChAdOx1 nCoV-19 group and 91 in the control group. Three events were classified as possibly related to a vaccine: one in the ChAdOx1 nCoV-19 group, one in the control group, and one in a participant who remains masked to group allocation. Interpretation ChAdOx1 nCoV-19 has an acceptable safety profile and has been found to be efficacious against symptomatic COVID-19 in this interim analysis of ongoing clinical trials

Climate variability and life history impact stress, thyroid, and immune markers in California sea lions (Zalophus californianus) during El Nino conditions.

De Rango E, Prager KC, Greig DJ, Hooper AW, Crocker DE. Climate variability and life history impact stress, thyroid, and immune markers in California sea lions (Zalophus californianus) during El Nino conditions. Conservation physiology. 2019;7(1): coz010.Wildlife is exposed to a diverse set of extrinsic and intrinsic stressors, such as climatic variation or life history constraints, which may impact individual health and fitness. El Nino and climatic anomalies between 2013 and 2016 had major ecological impacts on the California Current ecosystem. As top marine predators, California sea lions (CSL) experienced decreased prey availability and foraging success, impacting their nutritional state. We hypothesize that chronic stress to juvenile CSL increased during the 2015-2016 El Nino and that breeding represents a period of chronic stress for adults, which impact a variety of physiological processes. We opportunistically captured and sampled juvenile CSL (female, n=29; male, n=38) in central California and adult male CSL (n=76) in Astoria, Oregon and quantified a suite of analytes in serum as indicators of acute stress markers, metabolism and thyroid function, and adaptive immune response. We found that stress hormones and glucose were decreased in juvenile CSL during 2016 relative to 2015 and in adult male CSL after the breeding season, which may indicate chronic stress downregulating HPA (hypothalamic-pituitary-adrenal) axis sensitivity with associated metabolic impacts. Conversely, thyroid hormones for both juvenile and adult male CSL were increased, suggesting greater energetic requirements resulting from increased foraging activity during suboptimal conditions in juveniles and breeding tenure in adult males. Immunoglobulin IgG was elevated in juveniles in 2016 but reduced in adult males post-breeding. This suggests that juveniles may face immunostimulatory pressure during anomalously warm ocean environments; however, for adult males, breeding is a significant energetic cost resulting in reductions to immune function. Our results indicate that environmental conditions and life history stage may influence physiological responses in an important marine predator and a sentinel species of changing ocean ecosystems