142 research outputs found

    The Impact of the Organism on Its Descendants

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    Historically, evolutionary biologists have taken the view that an understanding of development is irrelevant to theories of evolution. However, the integration of several disciplines in recent years suggests that this position is wrong. The capacity of the organism to adapt to challenges from the environment can set up conditions that affect the subsequent evolution of its descendants. Moreover, molecular events arising from epigenetic processes can be transmitted from one generation to the next and influence genetic mutation. This in turn can facilitate evolution in the conditions in which epigenetic change was first initiated

    Behaviour, Development and Evolution

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    "The role of parents in shaping the characters of their children, the causes of violence and crime, and the roots of personal unhappiness are central to humanity. Like so many fundamental questions about human existence, these issues all relate to behavioural development. In this lucid and accessible book, eminent biologist Professor Sir Patrick Bateson suggests that the nature/nurture dichotomy we often use to think about questions of development in both humans and animals is misleading. Instead, he argues that we should pay attention to whole systems, rather than to simple causes, when trying to understand the complexity of development. In his wide-ranging approach Bateson discusses why so much behaviour appears to be well- designed. He explores issues such as ‘imprinting’ and its importance to the attachment of offspring to their parents; the mutual benefits that characterise communication between parent and offspring; the importance of play in learning how to choose and control the optimal conditions in which to thrive; and the vital function of adaptability in the interplay between development and evolution. Bateson disputes the idea that a simple link can be found between genetics and behaviour. What an individual human or animal does in its life depends on the reciprocal character of its transactions with the world about it. This knowledge also points to ways in which an animal's own behaviour can provide the variation that influences the subsequent course of evolution. This has relevance not only for our scientific approaches to the systems of development and evolution, but also on how humans change institutional rules that have become dysfunctional, or design public health measures when mismatches occur between themselves and their environments. It affects how we think about ourselves and our own capacity for change.

    Maternal state affects intestinal changes of rat pups at weaning

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    Two treatments of hooded rat (Rattus norvegicus) mothers after the birth of their pups affected the stage of development at which their pups started to take solid food and showed an increase in the expression of sucrase, an enzyme needed for digesting solid food. The pups of mothers that became pregnant in a post-partum oestrus showed the changes significantly earlier than those in the control group (Fig. 1A, B). The pups of mothers that had been mildly food-restricted after birth showed the changes significantly later than those in the control group. In brief, the pups of the pregnant mothers weaned first, the control pups next and those of food-restricted mothers weaned last. Differences in the timing of weaning between the three groups occurred in the absence of differences in pup body weight at the time of weaning. Within each experimental group, on the day in which sucrase expression showed the first detectable increase, sucrase activity was strongly predicted by the weight of the pups shortly after birth (Fig. 3). Pregnant mothers put on weight rapidly before implantation and their pups prepared for early weaning even though they did not differ in body weight from control pups (Fig. 4A, B). Food-restricted mothers were significantly lighter than control mothers and, with lighter pups before weaning started, settled for a longer period of suckling.Peer reviewe

    Social Enrichment during Postnatal Development Induces Transgenerational Effects on Emotional and Reproductive Behavior in Mice

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    Across species there is evidence that the quality of the early social environment can have a profound impact on neurobiology and behavior. In the present study we explore the effect of communal rearing conditions (three dams with three litters per cage) during the postnatal period on offspring (F1) and grand-offspring (F2) anxiety-like and maternal behavior in Balb/c mice. Females rearing pups in communal nests exhibited increased levels of postpartum maternal care and communal rearing was found to abolish sex-differences in weaning weights. In adulthood, communally reared offspring were observed to display reduced anxiety-like behavior when placed in a novel environment. When rearing their own offspring under standard conditions, communally reared females demonstrated higher levels of motivation to retrieve pups, built higher quality nests, and exhibited higher levels of postpartum care compared to standard reared females. When exposed to an intruder male, communally reared females were more subordinate and less aggressive. F2 offspring of communally reared females were observed to engage in reduced anxiety-like behavior, have larger litter sizes and an increased frequency of nursing on PND 1. Analysis of neuropeptide receptor levels suggest that a communal rearing environment may exert sustained effects on behavior through modification of oxytocin and vasopressin (V1a) receptor densities. Though Balb-C mice are often considered “socially-incompetent” and high in anxiety-like behavior, our findings suggest that through enrichment of the postnatal environment, these behavioral and neuroendocrine deficits may be attenuated both within and across generations

    The association of cold weather and all-cause and cause-specific mortality in the island of Ireland between 1984 and 2007

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.This article has been made available through the Brunel Open Access Publishing Fund.Background This study aimed to assess the relationship between cold temperature and daily mortality in the Republic of Ireland (ROI) and Northern Ireland (NI), and to explore any differences in the population responses between the two jurisdictions. Methods A time-stratified case-crossover approach was used to examine this relationship in two adult national populations, between 1984 and 2007. Daily mortality risk was examined in association with exposure to daily maximum temperatures on the same day and up to 6 weeks preceding death, during the winter (December-February) and cold period (October-March), using distributed lag models. Model stratification by age and gender assessed for modification of the cold weather-mortality relationship. Results In the ROI, the impact of cold weather in winter persisted up to 35 days, with a cumulative mortality increase for all-causes of 6.4% (95%CI=4.8%-7.9%) in relation to every 1oC drop in daily maximum temperature, similar increases for cardiovascular disease (CVD) and stroke, and twice as much for respiratory causes. In NI, these associations were less pronounced for CVD causes, and overall extended up to 28 days. Effects of cold weather on mortality increased with age in both jurisdictions, and some suggestive gender differences were observed. Conclusions The study findings indicated strong cold weather-mortality associations in the island of Ireland; these effects were less persistent, and for CVD mortality, smaller in NI than in the ROI. Together with suggestive differences in associations by age and gender between the two Irish jurisdictions, the findings suggest potential contribution of underlying societal differences, and require further exploration. The evidence provided here will hope to contribute to the current efforts to modify fuel policy and reduce winter mortality in Ireland

    Spot sputum samples are at least as good as early morning samples for identifying Mycobacterium tuberculosis

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    Supported by the Global Alliance for TB Drug Development with support from the Bill and Melinda Gates Foundation, the European and Developing Countries Clinical Trials Partnership (Grant IP.2007.32011.011), US Agency for International Development, UK Department for International Development, Directorate General for International Cooperation of the Netherlands, Irish Aid, Australia Department of Foreign Affairs and Trade, National Institutes of Health, AIDS Clinical Trials Group. The study was also supported by grants from the National Institute of Allergy and Infectious Diseases (NIAID) (UM1AI068634, UM1 AI068636, and UM1AI106701) and by NIAID grants to the University of KwaZulu Natal, South Africa, AIDS Clinical Trials Group (ACTG) site 31422 (1U01AI069469); to the Perinatal HIV Research Unit, Chris Hani Baragwanath Hospital, South Africa, ACTG site 12301 (1U01AI069453); and to the Durban International Clinical Trials Unit, South Africa, ACTG site 11201 (1U01AI069426). Bayer Healthcare for donated moxifloxacin and Sanofi donated rifampin.Background:  The use of early morning sputum samples (EMS) to diagnose tuberculosis (TB) can result in treatment delay given the need for the patient to return to the clinic with the EMS, increasing the chance of patients being lost during their diagnostic workup. However, there is little evidence to support the superiority of EMS over spot sputum samples. In this new analysis of the REMoxTB study, we compare the diagnostic accuracy of EMS with spot samples for identifying Mycobacterium tuberculosis pre- and post-treatment. Methods:  Patients who were smear positive at screening were enrolled into the study. Paired sputum samples (one EMS and one spot) were collected at each trial visit pre- and post-treatment. Microscopy and culture on solid LJ and liquid MGIT media were performed on all samples; those missing corresponding paired results were excluded from the analyses. Results:  Data from 1115 pre- and 2995 post-treatment paired samples from 1931 patients enrolled in the REMoxTB study were analysed. Patients were recruited from South Africa (47%), East Africa (21%), India (20%), Asia (11%), and North America (1%); 70% were male, median age 31 years (IQR 24–41), 139 (7%) co-infected with HIV with a median CD4 cell count of 399 cells/μL (IQR 318–535). Pre-treatment spot samples had a higher yield of positive Ziehl–Neelsen smears (98% vs. 97%, P = 0.02) and LJ cultures (87% vs. 82%, P = 0.006) than EMS, but there was no difference for positivity by MGIT (93% vs. 95%, P = 0.18). Contaminated and false-positive MGIT were found more often with EMS rather than spot samples. Surprisingly, pre-treatment EMS had a higher smear grading and shorter time-to-positivity, by 1 day, than spot samples in MGIT culture (4.5 vs. 5.5 days, P < 0.001). There were no differences in time to positivity in pre-treatment LJ culture, or in post-treatment MGIT or LJ cultures. Comparing EMS and spot samples in those with unfavourable outcomes, there were no differences in smear or culture results, and positive results were not detected earlier in Kaplan–Meier analyses in either EMS or spot samples. Conclusions:  Our data do not support the hypothesis that EMS samples are superior to spot sputum samples in a clinical trial of patients with smear positive pulmonary TB. Observed small differences in mycobacterial burden are of uncertain significance and EMS samples do not detect post-treatment positives any sooner than spot samples.Publisher PDFPeer reviewe

    Molecular bacterial load assay, a culture-free biomarker for rapid and accurate quantification of sputum Mycobacterium tuberculosis bacillary load during treatment

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    A molecular assay to quantify Mycobacterium tuberculosis is described. In vitro, 98% (n = 96) of sputum samples with a known number of bacilli (107 to 102 bacilli) could be enumerated within 0.5 log10. In comparison to culture, the molecular bacterial load (MBL) assay is unaffected by other microorganisms present in the sample, results are obtained more quickly (within 24 h) and are seldom inhibited (0.7% samples), and the MBL assay critically shows the same biphasic decline as observed longitudinally during treatment. As a biomarker of treatment response, the MBL assay responds rapidly, with a mean decline in bacterial load for 111 subjects of 0.99 log10 (95% confidence interval [95% CI], 0.81 to 1.17) after 3 days of chemotherapy. There was a significant association between the rate of bacterial decline during the same 3 days and bacilli ml−1 sputum at day 0 (linear regression, P = 0.0003) and a 3.62 increased odds ratio of relapse for every 1 log10 increase in pretreatment bacterial load (95% CI, 1.53 to 8.59)

    Precis of Vaulting Ambition: Sociobiology and the Quest for Human Nature

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    The debate about the credentials of sociobiology has persisted because scholars have failed to distinguish the varieties of sociobiology and because too little attention has been paid to the details of the arguments that are supposed to support the provocative claims about human social behavior. I seek to remedy both dcfieieneies. After analysis of the relationships among different kinds of sociobiology and contemporary evolutionary theory, I attempt to show how some of the studies of the behavior of nonhuman animals meet the methodological standards appropriate to evolutionary research. I contend that the efforts of E. O. Wilson, Richard Alexander, Charles Lumsden, and others to generate conclusions about human nature are flawed, both because they apply evolutionary ideas in an unrigorous fashion and because they use dubious assumptions to connect their evolutionary analyses with their conclusions. This contention rests on analyses of many of the major sociobiological proposals about human social behavior, including: differences in sex roles, racial hostility, homosexuality, conflict between parents and adolescent offspring, incest avoidance, the avunculate, alliances in combat, female infanticide, and gene-culture coevolution. Vaulting Ambition thus seeks to identify what is good in sociobiology, to expose the errors of premature speculations about human nature, and to prepare the way for serious study of the evolution of human social behavior

    Methane flux from flowback operations at a shale gas site

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    We report measurements of methane (CH4) mixing ratios and emission fluxes derived from sampling at a monitoring station at an exploratory shale gas extraction facility in Lancashire, England. Elevated ambient CH4 mixing ratios were recorded in January 2019 during a period of cold-venting associated with a nitrogen lift process at the facility. These processes are used to clear the well to stimulate flow of natural gas from the target shale. Estimates of CH4 flux during the emission event were made using three independent modeling approaches: Gaussian plume dispersion (following both a simple Gaussian plume inversion and the US EPA OTM 33-A method), and a Lagrangian stochastic transport model (WindTrax). The three methods yielded an estimated peak CH4 flux during January 2019 of approximately 70 g s−1. The total mass of CH4 emitted during the six-day venting period was calculated to be 2.9, 4.2 ± 1.4(1σ) and 7.1 ± 2.1(1σ) tonnes CH4 using the simple Gaussian plume model, WindTrax, and OTM-33A methods, respectively. Whilst the flux approaches all agreed within 1σ uncertainty, an estimate of 4.2 (± 1.4) tonnes CH4 represents the most confident assessment due to the explicit modeling of advection and meteorological stability permitted using the WindTrax model. This mass is consistent with fluxes calculated by the Environment Agency (in the range 2.7 to 6.8 tonnes CH4), using emission data provided by the shale site operator to the regulator. This study provides the first CH4 emission estimate for a nitrogen lift process and the first-reported flux monitoring of a UK shale gas site, and contributes to the evaluation of the environmental impacts of shale gas operations worldwide. This study also provides forward guidance on future monitoring applications and flux calculation in transient emission events. Implications: This manuscript discusses atmospheric measurements near to the UK’s first hydraulic fracturing facility, which has very high UK public, media, and policy interest. The focus of this manuscript is on a single week of data in which a large venting event at the shale gas site saw emissions of ~4 tonnes of methane to atmosphere, in breach of environmental permits. These results are likely to beresults are likely to be reported by the media and may influence future policy decisions concerning the UK hydraulic fracturing industry
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