864 research outputs found

    Ecological knowledge, leadership, and the evolution of menopause in killer whales

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    This is the final version of the article. Available from Elsevier via the DOI in this record.There is another record in ORE for this publication: http://hdl.handle.net/10871/16488Classic life-history theory predicts that menopause should not occur because there should be no selection for survival after the cessation of reproduction [1]. Yet, human females routinely live 30 years after they have stopped reproducing [2]. Only two other species-killer whales (Orcinus orca) and short-finned pilot whales (Globicephala macrorhynchus) [3, 4]-have comparable postreproductive lifespans. In theory, menopause can evolve via inclusive fitness benefits [5, 6], but the mechanisms by which postreproductive females help their kin remain enigmatic. One hypothesis is that postreproductive females act as repositories of ecological knowledge and thereby buffer kin against environmental hardships [7, 8]. We provide the first test of this hypothesis using a unique long-term dataset on wild resident killer whales. We show three key results. First, postreproductively aged females lead groups during collective movement in salmon foraging grounds. Second, leadership by postreproductively aged females is especially prominent in difficult years when salmon abundance is low. This finding is critical because salmon abundance drives both mortality and reproductive success in resident killer whales [9, 10]. Third, females are more likely to lead their sons than they are to lead their daughters, supporting predictions of recent models [5] of the evolution of menopause based on kinship dynamics. Our results show that postreproductive females may boost the fitness of kin through the transfer of ecological knowledge. The value gained from the wisdom of elders can help explain why female resident killer whales and humans continue to live long after they have stopped reproducing.This research was funded by a Natural Environment Research Council grant (NE/K01286X/1) to D.P.C., D.W.F., and M.A.C

    Imbalanced Multi-Modal Multi-Label Learning for Subcellular Localization Prediction of Human Proteins with Both Single and Multiple Sites

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    It is well known that an important step toward understanding the functions of a protein is to determine its subcellular location. Although numerous prediction algorithms have been developed, most of them typically focused on the proteins with only one location. In recent years, researchers have begun to pay attention to the subcellular localization prediction of the proteins with multiple sites. However, almost all the existing approaches have failed to take into account the correlations among the locations caused by the proteins with multiple sites, which may be the important information for improving the prediction accuracy of the proteins with multiple sites. In this paper, a new algorithm which can effectively exploit the correlations among the locations is proposed by using Gaussian process model. Besides, the algorithm also can realize optimal linear combination of various feature extraction technologies and could be robust to the imbalanced data set. Experimental results on a human protein data set show that the proposed algorithm is valid and can achieve better performance than the existing approaches

    Chromatic Illumination Discrimination Ability Reveals that Human Colour Constancy Is Optimised for Blue Daylight Illuminations

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    The phenomenon of colour constancy in human visual perception keeps surface colours constant, despite changes in their reflected light due to changing illumination. Although colour constancy has evolved under a constrained subset of illuminations, it is unknown whether its underlying mechanisms, thought to involve multiple components from retina to cortex, are optimised for particular environmental variations. Here we demonstrate a new method for investigating colour constancy using illumination matching in real scenes which, unlike previous methods using surface matching and simulated scenes, allows testing of multiple, real illuminations. We use real scenes consisting of solid familiar or unfamiliar objects against uniform or variegated backgrounds and compare discrimination performance for typical illuminations from the daylight chromaticity locus (approximately blue-yellow) and atypical spectra from an orthogonal locus (approximately red-green, at correlated colour temperature 6700 K), all produced in real time by a 10-channel LED illuminator. We find that discrimination of illumination changes is poorer along the daylight locus than the atypical locus, and is poorest particularly for bluer illumination changes, demonstrating conversely that surface colour constancy is best for blue daylight illuminations. Illumination discrimination is also enhanced, and therefore colour constancy diminished, for uniform backgrounds, irrespective of the object type. These results are not explained by statistical properties of the scene signal changes at the retinal level. We conclude that high-level mechanisms of colour constancy are biased for the blue daylight illuminations and variegated backgrounds to which the human visual system has typically been exposed

    Complete genome organization of American hop latent virus and its relationship to carlaviruses

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    The complete genomic sequence of American hop latent virus (AHLV; genus Carlavirus) was determined. The genome consists of 8,601 nucleotides plus a 3′-polyadenylate tail. The genome encompasses six potential open reading frames (ORF) in the positive sense, and their organization is typical of other carlaviruses. Analysis of the coat protein coding sequence at both the nucleic acid level and the amino acid level indicates that AHLV is only remotely related to the other carlaviruses known to infect common hop. Polyclonal antibodies were produced against the bacterially expressed coat protein of AHLV. These antibodies differentiated between AHLV and other carlaviruses of hop

    Incidence of suicide, hospital-presenting non-fatal self-harm, and community-occurring non-fatal self-harm in adolescents in England (the iceberg model of self-harm): a retrospective study

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    Summary Background Little is known about the relative incidence of fatal and non-fatal self-harm in young people. We estimated the incidence of suicide, hospital-presenting non-fatal self-harm, and community-occurring non-fatal self-harm in adolescents in England. Methods We used national mortality statistics (Jan 1, 2011, to Dec 31, 2013), hospital monitoring data for five hospitals derived from the Multicentre Study of Self-Harm in England (Jan 1, 2011, to Dec 31, 2013), and data from a schools survey (2015) to estimate the incidence of fatal and non-fatal self-harm per 100 000 person-years in adolescents aged 12–17 years in England. We described these incidences in terms of an iceberg model of self-harm. Findings During 2011–13, 171 adolescents aged 12–17 years died by suicide in England (119 [70%] male and 133 [78%] aged 15–17 years) and 1320 adolescents presented to the study hospitals following non-fatal self-harm (1028 [78%] female and 977 [74%] aged 15–17 years). In 2015, 322 (6%) of 5506 adolescents surveyed reported self-harm in the past year in the community (250 [78%] female and 164 [51%] aged 15–17 years). In 12–14 year olds, for every boy who died by suicide, 109 attended hospital following self-harm and 3067 reported self-harm in the community, whereas for every girl who died by suicide, 1255 attended hospital for self-harm and 21 995 reported self-harm in the community. In 15–17 year olds, for every male suicide, 120 males presented to hospital with self-harm and 838 self-harmed in the community; whereas for every female suicide, 919 females presented to hospital for self-harm and 6406 self-harmed in the community. Hanging or asphyxiation was the most common method of suicide (125 [73%] of 171), self-poisoning was the main reason for presenting to hospital after self-harm (849 [71%] of 1195), and self-cutting was the main method of self-harm used in the community (286 [89%] of 322). Interpretation Ratios of fatal to non-fatal rates of self-harm differed between males and females and between adolescents aged 12–14 years and 15–17 years, with a particularly large number of females reporting self-harm in the community. Our findings emphasise the need for well resourced community and hospital-based mental health services for adolescents, with greater investment in school-based prevention. Funding UK Department of Health

    The teaching of recent and violent conflicts as challenges for history education

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    This paper has been written with the support of Projects EDU2015-65088P from the DGICYT (Ministry of Education, Spain) and also the Project PICT2012-1594 from the ANPCYT (Argentina) coordinated by the autho

    Jet production in charged current deep inelastic e⁺p scatteringat HERA

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    The production rates and substructure of jets have been studied in charged current deep inelastic e⁺p scattering for Q² > 200 GeV² with the ZEUS detector at HERA using an integrated luminosity of 110.5 pb⁻¹. Inclusive jet cross sections are presented for jets with transverse energies E_{T}^{jet} > 5 GeV. Measurements of the mean subjet multiplicity, 〈n_{sbj}〉, of the inclusive jet sample are presented. Predictions based on parton-shower Monte Carlo models and next-to-leading-order QCD calculations are compared to the measurements. The value of α_{s} (M_{z}), determined from 〈n_{sbj}〉 at y_{cut} = 10⁻² for jets with 25 < E_{T}^{jet} < 119 GeV, is α_{s} (M_{z}) = 0.1202 ± 0.0052 (stat.)_{-0.0019}^{+0.0060} (syst.)_{-0.0053}^{+0.0065} (th.). The mean subjet multiplicity as a function of Q² is found to be consistent with that measured in NC DIS

    A Spoonful of Math Helps the Medicine Go Down: An Illustration of How Healthcare can Benefit from Mathematical Modeling and Analysis

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    <p>Abstract</p> <p>Objectives</p> <p>A recent joint report from the Institute of Medicine and the National Academy of Engineering, highlights the benefits of--indeed, the need for--mathematical analysis of healthcare delivery. Tools for such analysis have been developed over decades by researchers in Operations Research (OR). An OR perspective typically frames a complex problem in terms of its essential mathematical structure. This article illustrates the use and value of the tools of operations research in healthcare. It reviews one OR tool, queueing theory, and provides an illustration involving a hypothetical drug treatment facility.</p> <p>Method</p> <p>Queueing Theory (QT) is the study of waiting lines. The theory is useful in that it provides solutions to problems of waiting and its relationship to key characteristics of healthcare systems. More generally, it illustrates the strengths of modeling in healthcare and service delivery.</p> <p>Queueing theory offers insights that initially may be hidden. For example, a queueing model allows one to incorporate randomness, which is inherent in the actual system, into the mathematical analysis. As a result of this randomness, these systems often perform much worse than one might have guessed based on deterministic conditions. Poor performance is reflected in longer lines, longer waits, and lower levels of server utilization.</p> <p>As an illustration, we specify a queueing model of a representative drug treatment facility. The analysis of this model provides mathematical expressions for some of the key performance measures, such as average waiting time for admission.</p> <p>Results</p> <p>We calculate average occupancy in the facility and its relationship to system characteristics. For example, when the facility has 28 beds, the average wait for admission is 4 days. We also explore the relationship between arrival rate at the facility, the capacity of the facility, and waiting times.</p> <p>Conclusions</p> <p>One key aspect of the healthcare system is its complexity, and policy makers want to design and reform the system in a way that affects competing goals. OR methodologies, particularly queueing theory, can be very useful in gaining deeper understanding of this complexity and exploring the potential effects of proposed changes on the system without making any actual changes.</p
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