2,848 research outputs found

    Uncrewed aircraft system spherical photography for the vertical characterization of canopy structural traits

    Get PDF
    The plant area index (PAI) is a structural trait that succinctly parametrizes the foliage distribution of a canopy and is usually estimated using indirect optical techniques such as digital hemispherical photography. Critically, on-the-ground photographic measurements forgo the vertical variation of canopy structure which regulates the local light environment. Hence new approaches are sought for vertical sampling of traits. We present an uncrewed aircraft system (UAS) spherical photographic method to obtain structural traits throughout the depth of tree canopies. Our method explained 89% of the variation in PAI when compared with ground-based hemispherical photography. When comparing UAS vertical trait profiles with airborne laser scanning data, we found highest agreement in an open birch (Betula pendula/pubescens) canopy. Minor disagreement was found in dense spruce (Picea abies) stands, especially in the lower canopy. Our new method enables easy estimation of the vertical dimension of canopy structural traits in previously inaccessible spaces. The method is affordable and safe and therefore readily usable by plant scientists.Peer reviewe

    Searching for signatures of selection in Iberian honey bee (Apis mellifera iberiensis) using whole genome sequences

    Get PDF
    The Iberian Peninsula comprises a diverse set of habitats. It was an important glacial refugium during the Pleistocene and has served as a bridge for populations migrating between Africa and Europe, resulting in a complex mix of ancestry and diversity. The Iberian honey bee (A. m. iberiensis) is no exception and has been the subject of numerous incongruent population genetic surveys. Recent mtDNA and SNP analyses indicate a steep northeastern-southwestern cline of African ancestry along the peninsula, which has been explained by selection. Advances in DNA sequencing technology and computational tools provide unprecedented opportunities to study demography, search for signatures of selection across the genome and illuminate its role in shaping genomic diversity. We used Illumina technology to sequence the whole genomes of 86 Iberian honeybees, collected across three longitudinal transects in the Iberian Peninsula and spanning semi-arid climates in the southeastern peninsula to oceanic in the North-West. The dataset was first analyzed for FST-outliers, CLR (composite-likelihood ratio) and EHH (Extended Haplotype Homozygosity) methods were further deployed to evaluate polymorphisms implicated in local adaptation and possibly in the response to human- mediated environmental changes, including known and novel variants in genes related to behavior, vision, xenobiotic detoxification and immune response.info:eu-repo/semantics/publishedVersio

    Closed String Tachyon Condensation on Twisted Circles

    Full text link
    We study IIA/B string theory compactified on twisted circles. These models possess closed string tachyons and reduce to type 0B/A theory in a special limit. Using methods of gauged linear sigma models and mirror symmetry we construct a conformal field theory which interpolates between these models and flat space via an auxiliary Liouville direction. Interpreting motion in the Liouville direction as renormalization group flow, we argue that the end point of tachyon condensation in all these models (including 0B/A theory) is supersymmetric type II theory. We also find a zero-slope limit of these models which is best described in a T-dual picture as a type II NS-NS fluxbrane. In this limit tachyon condensation is an interesting and well posed problem in supergravity. We explicitly determine the tachyon as a fluctuation of supergravity fields, and perform a rudimentary numerical analysis of the relevant flows.Comment: 21 pages plus appendices (12 pages), harvmac, 1 fig, v2: minor changes and references added, v3: minor changes version published in JHE

    Searching for signatures of selection in the Iberian honey bee (Apis mellifera iberiensis) using allele-environment association approaches

    Get PDF
    In the current context of a global human-mediated environmental crisis, understanding which genes and mechanisms are responsible for adaptation to different climates will enable predictions on how organisms will respond to a rapidly changing world. This is particularly important for the honey bee, a key-stone species for ecosystem functioning and economy, which is facing increasing pressures from the effects of intensified land use, climate change, and the spread of pests and pathogens. The aim of this work is searching for signatures of selection along the genome of 87 individuals using two different allele-environment association approaches.JC-G and DH are supported by Fundação para a Ciência e Tecnologia (FCT) through the scholarships SFRH/BD/68682/2010 and SFRH/BD/84195/2012, respectively. This research was funded by FCT and COMPETE/QREN/EU through the project PTDC/BIABEC/ 099640/2008 and BiodivERsA-FACCE2014-91. Bioinformatic analyses were performed using resources at the Uppsala Multidisciplinary Center for Advanced Computational Science (UPPMAX)info:eu-repo/semantics/publishedVersio

    First observations of Weddell seals foraging in sponges in Erebus Bay, Antarctica

    Get PDF
    Attaching cameras to marine mammals allows for first-hand observation of underwater behaviours that may otherwise go unseen. While studying the foraging behaviour of 26 lactating Weddell seals (Leptonychotes weddellii) in Erebus Bay during the austral spring of 2018 and 2019, we witnessed three adults and one pup investigating the cavities of Rossellidae glass sponges, with one seal visibly chewing when she removed her head from the sponge. To our knowledge, this is the first report of such behaviour. While the prey item was not identifiable, some Trematomus fish (a known Weddell seal prey) use glass sponges for shelter and in which to lay their eggs. Three of the four sponge foraging observations occurred around 13:00 (NZDT). Two of the three sponge foraging adults had higher-than-average reproductive rates, and the greatest number of previous pups of any seal in our study population, each having ten pups in 12 years. This is far higher than the study population average of three previous pups (± 2.6 SD). This novel foraging strategy may have evolved in response to changes in prey availability, and could offer an evolutionary advantage to some individuals that exploit prey resources that others may not. Our observations offer new insight into the foraging behaviours of one of the world’s most studied marine mammals. Further research on the social aspects of Weddell seal behaviour may increase our understanding of the extent and mechanisms of behavioural transfer between conspecifics. Research into the specific foraging behaviour of especially successful or experienced breeders is also warranted

    The determinants of election to the United Nations Security Council

    Get PDF
    This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s11127-013-0096-4.The United Nations Security Council (UNSC) is the foremost international body responsible for the maintenance of international peace and security. Members vote on issues of global importance and consequently receive perks—election to the UNSC predicts, for instance, World Bank and IMF loans. But who gets elected to the UNSC? Addressing this question empirically is not straightforward as it requires a model that allows for discrete choices at the regional and international levels; the former nominates candidates while the latter ratifies them. Using an original multiple discrete choice model to analyze a dataset of 180 elections from 1970 to 2005, we find that UNSC election appears to derive from a compromise between the demands of populous countries to win election more frequently and a norm of giving each country its turn. We also find evidence that richer countries from the developing world win election more often, while involvement in warfare lowers election probability. By contrast, development aid does not predict election

    Adaptação local na abelha ibérica

    Get PDF
    Perceber a base genética do processo de adaptação permite uma previsão de como os organismos poderão responder a mudanças ambientais. A sequenciação de genomas a baixo custo, juntamente com os avanços das ferramentas estatísticas e computacionais possibilitam a compreensão da base genética da adaptação. O objectivo deste trabalho é o estudo da adaptação local da abelha ibérica, tendo como base algoritmos que permitem a incorporação de dados genéticos e ambientais. A Península Ibérica constituiu um local de interesse para este tipo de estudos por ser constituída por uma diversidade climática como Mediterrânico e Atlântico. Foram sequenciados 86 genomas de indivíduos distribuídos em 3 transectos (Atlântico, Central e Mediterrâneo) de forma a representar a diversidade climática existente na Península Ibérica. Em cada ponto de amostragem os dados de latitude e longitude foram recolhidos e variáveis ambientais foram retiradas das bases de dados WorldClim e Climatic Research Unit. Os métodos LFMM e Samβada, que integram informação genética e ambiental foram utilizados para procurar sinais de selecção. A vantagem destes métodos é que se pode perceber quais as variáveis ambientais que exercem uma pressão selectiva e que genes estão associados a cada variável. No total foram identificados 1289449 SNPs, dos quais 2193 mostraram estar significativamente associados com variáveis ambientais. Estes estão localizados em 826 genes. No conjunto das variáveis ambientais utilizadas, a longitude, latitude e precipitação apresentaram um maior num de SNPs associados. Foram encontrados genes com diversas funções, por exemplo quatro genes parecem relacionados com o desenvolvimento do sistema imunitário e este encontram associados à longitude, para a latitude proteínas de ligação parecem ser predominantes, já na precipitação aparecem genes relacionados com a morfogénese, actividade transportadora transmembranar e actividade olfactória. Este estudo representa primeira tentativa de compreender a base genética da adaptação local a partir de genomas completos.Agradecemos aos numerosos apicultores e técnicos de associações e também a A. Pajuelo, Andreia Brandão, Inês Moura, Margarida Neto, Irene Munoz, Pilar de la Rua, João C. Azevedo, e João Paulo Castro pela colaboração na amostragem. DH e JCG são financiados pela FCT através das bolsas de doutoramento SFRH/BD/84195/2012 e SFRH/BD/68682/2010, respetivamente. Este estudo foi financiado pelo projeto PTDC/BIA-BEC/099640/2008 (Fundação Ciência e Tecnologia, FCT, e COMPETE/QREN/EU). Cátia Neves é financiada através do concurso conjunto 2013-2014 BiodivErsA/FACCE-JPI, com a Fundação para a Ciência e Tecnologia como financiador nacional. As analises bioinformáticas foram efetuadas usando os recursos do "Uppsala Multidisciplinary Center for Advanced Computational Science (UPPMAX)", Universidade de Uppsala, Suécia.info:eu-repo/semantics/publishedVersio

    Variants of the serotonin transporter gene and NEO-PI-R Neuroticism: No association in the BLSA and SardiNIA samples

    Full text link
    The polymorphism in the serotonin transporter gene promoter region (5-HTTLPR) is by far the most studied variant hypothesized to influence Neuroticism-related personality traits. The results of previous studies have been mixed and appear moderated by the personality questionnaire used. Studies that used the TCI to assess Harm Avoidance or the EPQ to assess Neuroticism have found no association with the 5-HTTLPR. However, studies that used the NEO-PI-R or related instruments (NEO-PI, NEO-FFI) to measure Neuroticism have found some evidence of association. This study examines the association of variants in the serotonin transporter gene in a sample from a genetically isolated population within Sardinia (Italy) that is several times larger than previous samples that used the NEO-PI-R (N = 3,913). The association was also tested in a sample (N = 548) from the Baltimore Longitudinal Study of Aging (BLSA), in which repeated NEO-PI-R assessments were obtained. In the SardiNIA sample, we found no significant association of the 5-HTTLPR genotypes with Neuroticism or its facets (Anxiety, Angry-Hostility, Depression, Self-Consciousness, Impulsiveness, and Vulnerability). In the BLSA sample, we found lower scores on Neuroticism traits for the heterozygous group, which is inconsistent with previous studies. We also examined eight SNPs in the SardiNIA (N = 3,972) and nine SNPs in the BLSA (N = 1,182) that map within or near the serotonin transporter gene (SLC6A4), and found no association. Along with other large studies that used different phenotypic measures and found no association, this study substantially increases the evidence against a link between 5-HTT variants and Neuroticism-related traits. © 2009 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64573/1/30932_ftp.pd

    Ethnic dissimilarity predicts belonging motive frustration and reduced organizational attachment

    Get PDF
    Some empirical studies show negative consequences of being demographically different from one’s group, but the underlying psychological mechanisms are not well understood. To address this gap, we investigated the role of the belonging and distinctiveness motives in individuals’ experiences of being ethnically dissimilar from their group. We propose that ethnic dissimilarity satisfies group members’ need for distinctiveness whereas it frustrates members’ need for belonging, and this frustration reduces their organizational attachment. An experimental study showed that ethnic dissimilarity led to heightened arousal of the belonging motive, indicating that this motive was frustrated. In a naturalistic study of real-life student groups, ethnic dissimilarity was associated with frustrated belonging, which in turn was associated with reduced organizational attachment. This paper contributes to the literature on demographic dissimilarity in groups by closely examining the effect of demographic dissimilarity on group members’ fundamental motives and reactions to group membership
    • …
    corecore