1,232 research outputs found

    Psychological and physiological adaptations to sperm competition in humans

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    Postcopulatory competition between males, in the form of sperm competition, is a widespread phenomenon in many animal species. The extent to which sperm competition has been an important selective pressure during human evolution remains controversial, however. The authors review critically the evidence that human males and females have psychological, behavioral, and physiological adaptations that evolved in response to selection pressures associated with sperm competition. The authors consider, using evidence from contemporary societies, whether sperm competition is likely to have been a significant adaptive problem for ancestral humans and examine the evidence suggesting that human males have physiological and psychological mechanisms that allow for “prudent” sperm allocation in response to variations in the risk of sperm competition

    Comparing groups versus individuals in decision making: A systematic review protocol

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    Background Biodiversity management requires effective decision making at various stages. However decision making in the real world is complex, driven by multiple factors and involves a range of stakeholders. Understanding the factors that influence decision making is crucial to addressing the conflicts that arise in conservation. Decisions can be made either by individuals or by groups. This precise context has been studied extensively for several decades by behavioural economists, social psychologists and intelligence analysts. The observations from these disciplines can offer useful insights for biodiversity conservation. A systematic review on group versus individual decision making is currently lacking. This systematic review would enable us to synthesize the key insights from these disciplines for a range of scenarios useful for conservation. Methods The review will document studies that have investigated differences between group and individual decision making. The focus will be on empirical studies; the comparators in this case are decisions made by individuals while the intervention is group decision making. Outcomes include level of bias in decision outcomes or group performance. The search terms will include various combinations of the words “group”, “individual” and “decision-making”. The searches will be conducted in major publication databases, google scholar and specialist databases. Articles will be screened at the title and abstract and full text level by two reviewers. After checking for internal validity, the articles will be synthesized into subsets of decision contexts in which decision making by groups and individuals have been compared. The review process, all extracted data, original studies identified in the systematic review process and inclusion and exclusion decisions will be freely available as Additional file 1 in the final review.NM is funded by the Fondation Weiner Anspach in Belgium. WJS is funded by Arcadia. LVD was supported under the Biodiversity and Ecosystem Service Sustainability (BESS) Programme, grant code NE/K015419/1. GES is funded by The Nature Conservancy.This is the final version of the article. It first appeared from BioMed Central via http://dx.doi.org/10.1186/s13750-016-0066-

    Conductivity of dielectric and thermal atom-wall interaction

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    We compare the experimental data of the first measurement of a temperature dependence of the Casimir-Polder force by Obrecht et al. [Phys. Rev. Lett. {\bf 98}, 063201 (2007)] with the theory taking into account small, but physically real, static conductivity of the dielectric substrate. The theory is found to be inconsistent with the data. The conclusion is drawn that the conductivity of dielectric materials should not be included in the model of the dielectric response in the Lifshitz theory. This conclusion obtained from the long separation measurement is consistent with related but different results obtained for semiconductors and metals at short separations.Comment: 4 pages, 2 figures; page size is correcte

    The trade off between diversity and quality for multi-objective workforce scheduling

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    In this paper we investigate and compare multi-objective and weighted single objective approaches to a real world workforce scheduling problem. For this difficult problem we consider the trade off in solution quality versus population diversity, for different sets of fixed objective weights. Our real-world workforce scheduling problem consists of assigning resources with the appropriate skills to geographically dispersed task locations while satisfying time window constraints. The problem is NP-Hard and contains the Resource Constrained Project Scheduling Problem (RCPSP) as a sub problem. We investigate a genetic algorithm and serial schedule generation scheme together with various multi-objective approaches. We show that multi-objective genetic algorithms can create solutions whose fitness is within 2% of genetic algorithms using weighted sum objectives even though the multi-objective approaches know nothing of the weights. The result is highly significant for complex real-world problems where objective weights are seldom known in advance since it suggests that a multi-objective approach can generate a solution close to the user preferred one without having knowledge of user preferences

    Dynamic modelling to predict the likelihood of plant species persisting in fragmented landscapes in the face of climate change

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    Many species are threatened by global climate change, but plants are particularly vulnerable because, as sessile organisms, they are unable to move to areas with more suitable conditions as the climate changes. Instead they must rely on their seeds dispersing far and often to keep pace with a changing climate. This problem is exacerbated by the fragmentation of natural landscapes by clearing for agricultural or urban development, or similarly by a species requirement for particular soil types or topography. Models can help predict how different species will be affected by climate change. Most previous modelling work on predicting the persistence of plant and other species under climate change has been static, regression style modelling, known as climate envelope modelling. This has focussed on predicting where suitable environments for a species will likely occur under possible future climatic conditions, based on the species’ distribution under current conditions. While the existence of suitable environments in a new climate is a necessary condition for a species’ persistence, for sessile organisms such as plants, the ability of a species to move and colonise these suitable environments is also likely to be a major limitation. There is therefore a need for models that account for the dynamic processes involved in plant species’ migration and colonisation in changing climates. This paper presents such a dynamic model, called PPunCC (Plant Persistence under Climate Change). We describe how the PPunCC model represents the important factors and processes likely to affect a plant species’ capacity to migrate across a landscape fast enough to keep pace with a changing climate, such as the rate of climate change, the degree of landscape fragmentation, and the plant species’ life history, seed production, dispersal, and establishment. We also discuss how the model could be used to inform management decisions regarding adaptation options such as assisted migration or the creation of large-scale corridors that increase the connectivity of fragmented landscapes in order to help species migrate naturally and find suitable environments in new climates

    Threats to biodiversity from cumulative human impacts in one of North America's last wildlife frontiers

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    Land‐use change is the largest proximate threat to biodiversity yet remains one of the most complex to manage. In British Columbia (BC), where large mammals roam extensive tracts of intact habitat, continued land‐use development is of global concern. Extant mammal diversity in BC is unrivalled in North America owing, in part, to its unique position at the intersection of alpine, boreal, and temperate biomes. Despite high conservation values, understanding of cumulative ecological impacts from human development is limited. Using cumulative‐effects‐assessment (CEA) methods, we assessed the current human footprint over 16 regional ecosystems and 7 large mammal species. Using historical and current range estimates of the mammals, we investigated impacts of human land use on species’ persistence. For ecosystems, we found that bunchgrass, coastal Douglas fir, and ponderosa pine have been subjected to over 50% land‐use conversion, and over 85% of their spatial extent has undergone either direct or estimated indirect impacts. Of the mammals we considered, wolves were the least affected by land conversion, yet all species had reduced ranges compared with historical estimates. We found evidence of a hard trade‐off between development and conservation, most clearly for mammals with large distributions and ecosystems with high levels of conversion. Rather than serve as a platform to monitor species decline, we strongly advocate these data be used to inform land‐use planning and to assess current conservation efforts. More generally, CEAs offer a robust tool to inform wildlife and habitat conservation at scale

    Evaluation of Valid VO2max Criteria for Graded Exercise Testing in Cancer Survivors

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    International Journal of Exercise Science 18(5): 443-455, 2025. Cardiovascular fitness (VO2max) predicts all-cause mortality and is vital to assess in cancer survivors (CS) for individualized exercise prescriptions. Metabolic carts confirm VO2max with respiratory exchange ratio (RER) \u3e1.10; other VO2max criteria include ≤10 beats/minute of maximal predicted heart rate and/or a rating of perceived exertion (RPE) of \u3e8 on the Modified Borg Scale. Another suggested criterion is respiratory frequency (Rf) \u3e 40 breaths per minute. These criteria are assumed applicable for all populations, but due to cancer-related toxicities, frequency and validity of traditional VO2max criteria usage in CS remains unconfirmed. The purpose was to evaluate the frequency of VO2max criterion achievement of RER and alternate maximal criteria using HR, RPE, and Rf in CS. Forty CS performed three graded exercise tests (GXT) using gas analysis, totaling 111 GXTs. Max RER, HR, RPE, and Rf were measured. Differences in successful VO2max criterion achievement frequency were assessed using a Cochran’s Q test and Pairwise Comparison Dunn test with Bonferroni adjustment. Maximal criteria were successfully met in 84%, 79%, 92%, and 43% of trials when evaluating RER, HR, RPE, and Rf, respectively. Significant differences occurred between Rf and all other measures (p \u3c 0.001); no significant differences occurred between RER, HR, RPE. Traditional VO2max criteria may be feasibly obtained and used in CS; HR and RPE are valid alternatives to RER, but Rf is not. The equivalency between RER, RPE, and HR suggests metabolic carts may be unnecessary for CS during maximal testing, increasing accessibility and validity of VO2max values

    Global Burden of Multiple Myeloma ASystematic Analysis for the Global Burden of Disease Study 2016

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    Introduction: Multiple myeloma (MM) is a plasma cell neoplasm with substantial morbidity and mortality. A comprehensive description of the global burden of MM is needed to help direct health policy, resource allocation, research, and patient care.Objective: To describe the burden of MM and the availability of effective therapies for 21 world regions and 195 countries and territories from 1990 to 2016.Design and Setting: We report incidence, mortality, and disability-adjusted life-year (DALY) estimates from the Global Burden of Disease 2016 study. Data sources include vital registration system, cancer registry, drug availability, and survey data for stem cell transplant rates. We analyzed the contribution of aging, population growth, and changes in incidence rates to the overall change in incident cases from 1990 to 2016 globally, by sociodemographic index (SDI) and by region. We collected data on approval of lenalidomide and bortezomib worldwide.Main Outcomes and Measures: Multiple myeloma mortality; incidence; years lived with disabilities; years of life lost; and DALYs by age, sex, country, and year.Results: Worldwide in 2016 there were 138 509 (95% uncertainty interval [UI], 121 000-155 480) incident cases of MM with an age-standardized incidence rate (ASIR) of 2.1 per 100 000 persons (95% UI, 1.8-2.3). Incident cases from 1990 to 2016 increased by 126% globally and by 106% to 192% for all SDI quintiles. The 3 world regions with the highest ASIR of MM were Australasia, North America, and Western Europe. Multiple myeloma caused 2.1 million (95% UI, 1.9-2.3 million) DALYs globally in 2016. Stem cell transplantation is routinely available in higher-income countries but is lacking in sub-Saharan Africa and parts of the Middle East. In 2016, lenalidomide and bortezomib had been approved in 73 and 103 countries, respectively.Conclusions and Relevance: Incidence of MM is highly variable among countries but has increased uniformly since 1990, with the largest increase in middle and low-middle SDI countries. Access to effective care is very limited in many countries of low socioeconomic development, particularly in sub-Saharan Africa. Global health policy priorities for MM are to improve diagnostic and treatment capacity in low and middle income countries and to ensure affordability of effective medications for every patient. Research priorities are to elucidate underlying etiological factors explaining the heterogeneity in myeloma incidence

    Chemopreventive Potential of Synergy1 and Soybean in Reducing Azoxymethane-Induced Aberrant Crypt Foci in Fisher 344 Male Rats

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    Synergy1, a prebiotic composed of Inulin and Oligofructose (1 : 1). Soybean meal is a natural source of isoflavones. The objective was to investigate the effects of feeding Synergy1 and SM on the incidence of azoxymethane- (AOM-) induced aberrant crypt foci (ACF) in Fisher 344 male rats. Rats (54) were randomly assigned to 9 groups (n = 6). Control group (C) was fed AIN-93G and treatment groups Syn1 and SM at 5% and 10% singly and in combinations. Rats were injected with two s/c injections of AOM at 7 and 8 weeks of age at 16 mg/kg body weight and killed at 17 weeks by CO2 asphyxiation. Colonic ACF enumeration and hepatic enzyme activities were measured. Reductions (%) in total ACF among treatment groups fed combinations were higher (67–77) compared to groups fed singly (52–64). Synergistic mechanisms among phytochemicals may be responsible suggesting protective role in colon carcinogenesis with implications in food product development
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