1,263 research outputs found

    Representation of Sound Objects within Early-Stage Auditory Areas: A Repetition Effect Study Using 7T fMRI.

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    Environmental sounds are highly complex stimuli whose recognition depends on the interaction of top-down and bottom-up processes in the brain. Their semantic representations were shown to yield repetition suppression effects, i. e. a decrease in activity during exposure to a sound that is perceived as belonging to the same source as a preceding sound. Making use of the high spatial resolution of 7T fMRI we have investigated the representations of sound objects within early-stage auditory areas on the supratemporal plane. The primary auditory cortex was identified by means of tonotopic mapping and the non-primary areas by comparison with previous histological studies. Repeated presentations of different exemplars of the same sound source, as compared to the presentation of different sound sources, yielded significant repetition suppression effects within a subset of early-stage areas. This effect was found within the right hemisphere in primary areas A1 and R as well as two non-primary areas on the antero-medial part of the planum temporale, and within the left hemisphere in A1 and a non-primary area on the medial part of Heschl's gyrus. Thus, several, but not all early-stage auditory areas encode the meaning of environmental sounds

    Estudo comparativo de algumas glândulas dos Vespoidea (Hymenoptera)

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    Los programas de educación náutica en la educación obligatoria en España: revisión sistemática

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    En los últimos años, los deportes náuticos están adquiriendo notoriedad en el ámbito educativo, pudiendo demostrar que son una herramienta valiosa para el desarrollo integral de los estudiantes. Sin embargo, no parece existir evidencia científica sobre el desarrollo y efecto de estos en los programas de educación náutica en España. Por ello, el objetivo de este estudio fue la realización de una revisión sistemática de los programas relacionados con la educación náutica en la educación Primaria y Secundaria en España. Además, proponer un meta-programada en la línea de esta temática. A partir de estos objetivos, se realizó la búsqueda en las bases de datos PubMed, Scopus, Dialnet, Web of Science y, posteriormente, en Google Académico y en el buscador de Google, entre 2008 hasta 2023 empleando las siguientes palabras clave: "programa escolar", "educación", "actividades náuticas".  Los resultados de la búsqueda muestran que los principales objetivos de estos programas son el fomento de actividades y deportes náuticos y el conocimiento del propio entorno. En cuanto a los contenidos, destaca el uso de los deportes de vela, y otros deportes como son piragüismo, windsurf, kayak o paddle surf, que empiezan por clases teóricas, para posteriormente, realizar las clases prácticas. En conclusión, se ha podido comprobar que, en la actualidad, se está haciendo un uso deportes náuticos en el ámbito educativo, lo que nos ha llevado a realizar un meta-programa donde se recojan la información más relevante de los objetivos, contenidos, metodología y evaluación

    PRODUTIVIDADE DO MILHETO EM TRÊS DENSIDADES DE SEMEADURA E DUAS ALTURAS DE CORTE

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    Com o objetivo de avaliar a produção do milheto (Pennisetum glaucum (L.)) em diferentes densidades de semeadura e manejado em duas alturas de corte, foi realizado um experimento na Fazenda Experimental da Universidade Federal de Goiás, no período de março a julho (safrinha) após a colheita da soja. O delineamento experimental utilizado foi blocos ao acaso em arranjo fatorial (3x2) com três densidades de semeadura (10, 15 e 20 kg.ha-¹) e duas alturas de corte (50 e 70 cm). Os dados foram analisados no programa SAS versão 9.2, considerando-se o efeito de densidade na parcela e altura na subparcela. As médias foram comparadas pelo teste Tukey a 5% de probabilidade. A densidade de semeadura não influenciou (P0,05) influência da densidade de semeadura ou da altura de corte. Por não ter afetado a produção de MS e por permitir maior período de utilização da pastagem com menor gasto com sementes no plantio, recomenda-se a densidade de semeadura de 10 kg.ha-¹ com corte do milheto aos 50 cm de altura. Palavras-chave: estresse hídrico; manejo; safrinha

    The Mating-Type Chromosome in the Filamentous Ascomycete Neurospora tetrasperma Represents a Model for Early Evolution of Sex Chromosomes

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    We combined gene divergence data, classical genetics, and phylogenetics to study the evolution of the mating-type chromosome in the filamentous ascomycete Neurospora tetrasperma. In this species, a large non-recombining region of the mating-type chromosome is associated with a unique fungal life cycle where self-fertility is enforced by maintenance of a constant state of heterokaryosis. Sequence divergence between alleles of 35 genes from the two single mating-type component strains (i.e. the homokaryotic mat A or mat a-strains), derived from one N. tetrasperma heterokaryon (mat A+mat a), was analyzed. By this approach we were able to identify the boundaries and size of the non-recombining region, and reveal insight into the history of recombination cessation. The non-recombining region covers almost 7 Mbp, over 75% of the chromosome, and we hypothesize that the evolution of the mating-type chromosome in this lineage involved two successive events. The first event was contemporaneous with the split of N. tetrasperma from a common ancestor with its outcrossing relative N. crassa and suppressed recombination over at least 6.6 Mbp, and the second was confined to a smaller region in which recombination ceased more recently. In spite of the early origin of the first “evolutionary stratum”, genealogies of five genes from strains belonging to an additional N. tetrasperma lineage indicate independent initiations of suppressed recombination in different phylogenetic lineages. This study highlights the shared features between the sex chromosomes found in the animal and plant kingdoms and the fungal mating-type chromosome, despite fungi having no separate sexes. As is often found in sex chromosomes of plants and animals, recombination suppression of the mating-type chromosome of N. tetrasperma involved more than one evolutionary event, covers the majority of the mating-type chromosome and is flanked by distal regions with obligate crossovers

    Histological basis of laminar MRI patterns in high resolution images of fixed human auditory cortex

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    Functional magnetic resonance imaging (fMRI) studies of the auditory region of the temporal lobe would benefit from the availability of image contrast that allowed direct identification of the primary auditory cortex, as this region cannot be accurately located using gyral landmarks alone. Previous work has suggested that the primary area can be identified in magnetic resonance (MR) images because of its relatively high myelin content. However, MR images are also affected by the iron content of the tissue and in this study we sought to confirm that different MR image contrasts did correlate with the myelin content in the grey matter and were not primarily affected by iron content as is the case in the primary visual and somatosensory areas. By imaging blocks of fixed post-mortem cortex in a 7 Tesla scanner and then sectioning them for histological staining we sought to assess the relative contribution of myelin and iron to the grey matter contrast in the auditory region. Evaluating the image contrast in T2*-weighted images and quantitative R2* maps showed a reasonably high correlation between the myelin density of the grey matter and the intensity of the MR images. The correlation with T1-weighted phase sensitive inversion recovery (PSIR) images was better than with the previous two image types, and there were clearly differentiated borders between adjacent cortical areas in these images. A significant amount of iron was present in the auditory region, but did not seem to contribute to the laminar pattern of the cortical grey matter in MR images. Similar levels of iron were present in the grey and white matter and although iron was present in fibres within the grey matter, these fibres were fairly uniformly distributed across the cortex. Thus we conclude that T1- and T2*-weighted imaging sequences do demonstrate the relatively high myelin levels that are characteristic of the deep layers in primary auditory cortex and allow it and some of the surrounding areas to be reliably distinguished

    High interannual variability in connectivity and genetic pool of a temperate clingfish matches oceanographic transport predictions

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    Adults of most marine benthic and demersal fish are site-attached, with the dispersal of their larval stages ensuring connectivity among populations. In this study we aimed to infer spatial and temporal variation in population connectivity and dispersal of a marine fish species, using genetic tools and comparing these with oceanographic transport. We focused on an intertidal rocky reef fish species, the shore clingfish Lepadogaster lepadogaster, along the southwest Iberian Peninsula, in 2011 and 2012. We predicted high levels of self-recruitment and distinct populations, due to short pelagic larval duration and because all its developmental stages have previously been found near adult habitats. Genetic analyses based on microsatellites countered our prediction and a biophysical dispersal model showed that oceanographic transport was a good explanation for the patterns observed. Adult sub-populations separated by up to 300 km of coastline displayed no genetic differentiation, revealing a single connected population with larvae potentially dispersing long distances over hundreds of km. Despite this, parentage analysis performed on recruits from one focal site within the Marine Park of Arrabida (Portugal), revealed self-recruitment levels of 2.5% and 7.7% in 2011 and 2012, respectively, suggesting that both long-and short-distance dispersal play an important role in the replenishment of these populations. Population differentiation and patterns of dispersal, which were highly variable between years, could be linked to the variability inherent in local oceanographic processes. Overall, our measures of connectivity based on genetic and oceanographic data highlight the relevance of long-distance dispersal in determining the degree of connectivity, even in species with short pelagic larval durations

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
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