1,057 research outputs found

    Moving Towards a Nuanced Understanding of Human Mating Preferences and Strategies: A Critique of Evolutionary Psychologists’ Emphasis on Sex Differences

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    This thesis examines how evolutionary psychologists study human mating preferences and strategies: the theories they test, the methods they use, and how they analyze their findings. Women’s long-term mate preferences for high status, tall, investing men with resources and men’s long-term mate preferences for young, beautiful women are discussed and critiqued. Evolutionary psychologists’ focus on and exaggeration of sex differences as well as the controversial nature of their claims illustrate the need for a multitude of perspectives in the scientific study of human mating. Two models for study are compared: the male competition, female choice (MCFC) model and the mutual mate choice (MMC) model. An MMC perspective may be important in correcting the overemphasis on sex differences in evolutionary psychology’s study of mating preferences and strategies

    The accretion origin of the Milky Way's stellar halo

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    We have used data from the Sloan Digital Sky Survey (SDSS) Data Release 5 to explore the overall structure and substructure of the stellar halo of the Milky Way using about 4 million color-selected main sequence turn-off stars. We fit oblate and triaxial broken power-law models to the data, and found a `best-fit' oblateness of the stellar halo 0.5<c/a<0.8, and halo stellar masses between Galactocentric radii of 1 and 40kpc of (3.7+/-1.2)x10^8 M_sun. The density profile of the stellar halo is approximately r^{-3}; it is possible that the power law slope is shallower inside 20kpc and steeper outside that radius. Yet, we found that all smooth and symmetric models were very poor fits to the distribution of stellar halo stars because the data exhibit a great deal of spatial substructure. We quantified deviations from a smooth oblate/triaxial model using the RMS of the data around the model profile on scales >~100pc, after accounting for the (known) contribution of Poisson uncertainties. The fractional RMS deviation of the actual stellar distribution from any smooth, parameterized halo model is >~40%: hence, the stellar halo is highly structured. We compared the observations with simulations of galactic stellar halos formed entirely from the accretion of satellites in a cosmological context by analysing the simulations in the same way as the data. While the masses, overall profiles, and degree of substructure in the simulated stellar halos show considerable scatter, the properties and degree of substructure in the Milky Way's halo match well the properties of a `typical' stellar halo built exclusively out of the debris from disrupted satellite galaxies. Our results therefore point towards a picture in which an important fraction of the Milky Way's stellar halo has been accreted from satellite galaxies.Comment: Submitted to the Astrophysical Journal. 14 pages; 11 figure

    Quantifying Kinematic Substructure in the Milky Way's Stellar Halo

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    We present and analyze the positions, distances, and radial velocities for over 4000 blue horizontal-branch (BHB) stars in the Milky Way's halo, drawn from SDSS DR8. We search for position-velocity substructure in these data, a signature of the hierarchical assembly of the stellar halo. Using a cumulative "close pair distribution" (CPD) as a statistic in the 4-dimensional space of sky position, distance, and velocity, we quantify the presence of position-velocity substructure at high statistical significance among the BHB stars: pairs of BHB stars that are close in position on the sky tend to have more similar distances and radial velocities compared to a random sampling of these overall distributions. We make analogous mock-observations of 11 numerical halo formation simulations, in which the stellar halo is entirely composed of disrupted satellite debris, and find a level of substructure comparable to that seen in the actually observed BHB star sample. This result quantitatively confirms the hierarchical build-up of the stellar halo through a signature in phase (position-velocity) space. In detail, the structure present in the BHB stars is somewhat less prominent than that seen in most simulated halos, quite possibly because BHB stars represent an older sub-population. BHB stars located beyond 20 kpc from the Galactic center exhibit stronger substructure than at rgc<20\rm r_{gc} < 20 kpc.Comment: 29 page, 10 figures, 1 table; accepted by APJ; for related article by another group see arXiv:1011.192

    IMCI and ETAT Integration at a Primary Healthcare Facility in Malawi:A Human Factors Approach

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    Abstract Background Integrated Management of Childhood Illness (IMCI) and Emergency Triage, Assessment and Treatment (ETAT) are guidelines developed by the World Health Organization to reach targets for reducing under-5 mortality. They were set out in the Millennium Development Goals. Each guideline was established separately so the purpose of this study was to understand how these systems have been integrated in a primary care setting and identify barriers and facilitators to this integration using a systems approach. Method Interviews were carried out with members of staff of different levels within a primary healthcare clinic in Malawi. Along with observations from the clinic this provided a well-rounded view of the running of the clinic. This data was then analysed using the SEIPS 2.0 work systems framework. The work system elements specified in this model were used to identify and categorise themes that influenced the clinic’s efficiency. Results A process map of the flow of patients through the clinic was created, showing the tasks undertaken and the interactions between staff and patients. In their interviews, staff identified several organisational elements that served as barriers to the implementation of care. They included workload, available resources, ineffective time management, delegation of roles and adaptation of care. In terms of the external environment there was a lack of clarity over the two sets of guidelines and how they were to be integrated which was a key barrier to the process. Under the heading of tools and technology a lack of guideline copies was identified as a barrier. However, the health passport system and other forms of recording were highlighted as being important facilitators. Other issues highlighted were the lack of transport provided, challenges regarding teamwork and attitudes of members of staff, patient factors such as their beliefs and regard for the care and education provided by the clinic. Conclusions This study provides the first information on the challenges and issues involved in combining IMCI and ETAT and identified a number of barriers. These barriers included a lack of resources, staff training and heavy workload. This provided areas to work on in order to improve implementation

    Association of Accelerometry-Measured Physical Activity and Cardiovascular Events in Mobility-Limited Older Adults: The LIFE (Lifestyle Interventions and Independence for Elders) Study.

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    BACKGROUND:Data are sparse regarding the value of physical activity (PA) surveillance among older adults-particularly among those with mobility limitations. The objective of this study was to examine longitudinal associations between objectively measured daily PA and the incidence of cardiovascular events among older adults in the LIFE (Lifestyle Interventions and Independence for Elders) study. METHODS AND RESULTS:Cardiovascular events were adjudicated based on medical records review, and cardiovascular risk factors were controlled for in the analysis. Home-based activity data were collected by hip-worn accelerometers at baseline and at 6, 12, and 24&nbsp;months postrandomization to either a physical activity or health education intervention. LIFE study participants (n=1590; age 78.9±5.2 [SD] years; 67.2% women) at baseline had an 11% lower incidence of experiencing a subsequent cardiovascular event per 500&nbsp;steps taken per day based on activity data (hazard ratio, 0.89; 95% confidence interval, 0.84-0.96; P=0.001). At baseline, every 30&nbsp;minutes spent performing activities ≥500&nbsp;counts per minute (hazard ratio, 0.75; confidence interval, 0.65-0.89 [P=0.001]) were also associated with a lower incidence of cardiovascular events. Throughout follow-up (6, 12, and 24&nbsp;months), both the number of steps per day (per 500&nbsp;steps; hazard ratio, 0.90, confidence interval, 0.85-0.96 [P=0.001]) and duration of activity ≥500&nbsp;counts per minute (per 30&nbsp;minutes; hazard ratio, 0.76; confidence interval, 0.63-0.90 [P=0.002]) were significantly associated with lower cardiovascular event rates. CONCLUSIONS:Objective measurements of physical activity via accelerometry were associated with cardiovascular events among older adults with limited mobility (summary score &gt;10 on the Short Physical Performance Battery) both using baseline and longitudinal data. CLINICAL TRIAL REGISTRATION:URL: http://www.clinicaltrials.gov. Unique identifier: NCT01072500

    Dark sectors 2016 Workshop: community report

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    This report, based on the Dark Sectors workshop at SLAC in April 2016, summarizes the scientific importance of searches for dark sector dark matter and forces at masses beneath the weak-scale, the status of this broad international field, the important milestones motivating future exploration, and promising experimental opportunities to reach these milestones over the next 5-10 years

    MASTREE+: time-series of plant reproductive effort from six continents

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    Significant gaps remain in understanding the response of plant reproduction to environmental change. This is partly because measuring reproduction in long-lived plants requires direct observation over many years and such datasets have rarely been made publicly available. Here we introduce MASTREE+, a data set that collates reproductive time-series data from across the globe and makes these data freely available to the community. MASTREE+ includes 73,828 georeferenced observations of annual reproduction (e.g. seed and fruit counts) in perennial plant populations worldwide. These observations consist of 5971 population-level time-series from 974 species in 66 countries. The mean and median time-series length is 12.4 and 10 years respectively, and the data set includes 1122 series that extend over at least two decades (≥20 years of observations). For a subset of well-studied species, MASTREE+ includes extensive replication of time-series across geographical and climatic gradients. Here we describe the open-access data set, available as a.csv file, and we introduce an associated web-based app for data exploration. MASTREE+ will provide the basis for improved understanding of the response of long-lived plant reproduction to environmental change. Additionally, MASTREE+ will enable investigation of the ecology and evolution of reproductive strategies in perennial plants, and the role of plant reproduction as a driver of ecosystem dynamics.Additional co-authors: Ciprian Palaghianu, Mario Pesendorfer, Akiko Satake, Eliane Schermer, Andrew J. Tanentzap, Peter A. Thomas, Davide Vecchio, Andreas P. Wion, Thomas Wohlgemuth, Tingting Xue, Marie-Claire Aravena Acuña, Marcelo Daniel Barrera, Jessica H. Barton, Stan Boutin, Emma R. Bush, Sergio Donoso Calderón, Felipe S. Carevic, Carolina Volkmer de Castilho, Juan Manuel Cellini, Colin A. Chapman, Hazel Chapman, Francesco Chianucci, Patricia da Costa, Luc Croisé, Andrea Cutini, Ben Dantzer, R. Justin DeRose, Jean-Thoussaint Dikangadissi, Edmond Dimoto, Fernanda Lopes da Fonseca, Leonardo Gallo, Georg Gratzer, David F. Greene, Martín A. Hadad, Alejandro Huertas Herrera, Jill F. Johnstone, Urs Kalbitzer, Władysław Kantorowicz, Christie A. Klimas, Jonathan G. A. Lageard, Jeffrey Lane, Katharina Lapin, Mateusz Ledwoń, Abigail C. Leeper, Maria Vanessa Lencinas, Ana Cláudia Lira-Guedes, Michael C. Lordon, Paula Marchelli, Shealyn Marino, Harald Schmidt Van Marle, Andrew G. McAdam, Ludovic R. W. Momont, Manuel Nicolas, Lúcia Helena de Oliveira Wadt, Parisa Panahi, Guillermo Martínez Pastur, Thomas Patterson, Pablo Luis Peri, Łukasz Piechnik, Mehdi Pourhashemi, Claudia Espinoza Quezada, Fidel A. Roig, Karen Peña Rojas, Yamina Micaela Rosas, Silvio Schueler, Barbara Seget, Rosina Soler, Michael A. Steele, Mónica Toro-Manríquez, Caroline E. G. Tutin, Tharcisse Ukizintambara, Biplang Yadok, John L. Willis, Anita Zolles, Magdalena Żywiec, Davide Ascol
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