8,104 research outputs found

    Length correction for larval and early-juvenile Atlantic menhaden (Brevoortia tyrannus) after preservation in alcohol

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    Body length measurement is an important part of growth, condition, and mortality analyses of larval and juvenile fish. If the measurements are not accurate (i.e., do not reflect real fish length), results of subsequent analyses may be affected considerably (McGurk, 1985; Fey, 1999; Porter et al., 2001). The primary cause of error in fish length measurement is shrinkage related to collection and preservation (Theilacker, 1980; Hay, 1981; Butler, 1992; Fey, 1999). The magnitude of shrinkage depends on many factors, namely the duration and speed of the collection tow, abundance of other planktonic organisms in the sample (Theilacker, 1980; Hay, 1981; Jennings, 1991), the type and strength of the preservative (Hay, 1982), and the species of fish (Jennings, 1991; Fey, 1999). Further, fish size affects shrinkage (Fowler and Smith, 1983; Fey, 1999, 2001), indicating that live length should be modeled as a function of preserved length (Pepin et al., 1998; Fey, 1999)

    Effect of type of otolith and preparation technique on age estimation of larval and juvenile spot (Leiostomus xanthurus)

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    Otoliths of larval and juvenile fish provide a record of age, size, growth, and development (Campana and Neilson, 1985; Thorrold and Hare, 2002). However, determining the time of first increment formation in otoliths (Campana, 2001) and assessing the accuracy (deviation from real age) and precision (repeatability of increment counts from the same otolith) of increment counts are prerequisites for using otoliths to study the life history of fish (Campana and Moksness, 1991). For most fish species, first increment deposition occurs either at hatching, a day after hatching, or after first feeding and yolksac absorption (Jones, 1986; Thorrold and Hare, 2002). Increment deposition before hatching also occurs (Barkmann and Beck, 1976; Radtke and Dean, 1982). If first increment deposition does not occur at hatching, the standard procedure is to add a predetermined number to increment counts to estimate fish age (Campana and Neilson, 1985)

    Dissociating the Role of the Orbitofrontal Cortex and the Striatum in the Computation of Goal Values and Prediction Errors

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    To make sound economic decisions, the brain needs to compute several different value-related signals. These include goal values that measure the predicted reward that results from the outcome generated by each of the actions under consideration, decision values that measure the net value of taking the different actions, and prediction errors that measure deviations from individuals' previous reward expectations. We used functional magnetic resonance imaging and a novel decision-making paradigm to dissociate the neural basis of these three computations. Our results show that they are supported by different neural substrates: goal values are correlated with activity in the medial orbitofrontal cortex, decision values are correlated with activity in the central orbitofrontal cortex, and prediction errors are correlated with activity in the ventral striatum

    Value Computations in Ventral Medial Prefrontal Cortex during Charitable Decision Making Incorporate Input from Regions Involved in Social Cognition

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    Little is known about the neural networks supporting value computation during complex social decisions. We investigated this question using functional magnetic resonance imaging while subjects made donations to different charities. We found that the blood oxygenation level-dependent signal in ventral medial prefrontal cortex (VMPFC) correlated with the subjective value of voluntary donations. Furthermore, the region of the VMPFC identified showed considerable overlap with regions that have been shown to encode for the value of basic rewards at the time of choice, suggesting that it might serve as a common valuation system during decision making. In addition, functional connectivity analyses indicated that the value signal in VMPFC might integrate inputs from networks, including the anterior insula and posterior superior temporal cortex, that are thought to be involved in social cognition

    Open-domain topic identification of out-of-domain utterances using Wikipedia

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    Users of spoken dialogue systems (SDS) expect high quality interactions across a wide range of diverse topics. However, the implementation of SDS capable of responding to every conceivable user utterance in an informative way is a challenging problem. Multi-domain SDS must necessarily identify and deal with out-of-domain (OOD) utterances to generate appropriate responses as users do not always know in advance what domains the SDS can handle. To address this problem, we extend the current state-of-the-art in multi-domain SDS by estimating the topic of OOD utterances using external knowledge representation from Wikipedia. Experimental results on real human-to-human dialogues showed that our approach does not degrade domain prediction performance when compared to the base model. But more significantly, our joint training achieves more accurate predictions of the nearest Wikipedia article by up to about 30% when compared to the benchmarks

    Cosmic Ray Physics with the LOFAR Radio Telescope

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    The LOFAR radio telescope is able to measure the radio emission from cosmic ray induced air showers with hundreds of individual antennas. This allows for precision testing of the emission mechanisms for the radio signal as well as determination of the depth of shower maximum XmaxX_{\max}, the shower observable most sensitive to the mass of the primary cosmic ray, to better than 20 g/cm2^2. With a densely instrumented circular area of roughly 320 m2^2, LOFAR is targeting for cosmic ray astrophysics in the energy range 101610^{16} - 101810^{18} eV. In this contribution we give an overview of the status, recent results, and future plans of cosmic ray detection with the LOFAR radio telescope.Comment: Proceedings of the 26th Extended European Cosmic Ray Symposium (ECRS), Barnaul/Belokurikha, 201

    The experiences of spirituality among adults with mental health difficulties: a qualitative systematic review

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    Aims Despite an increasing awareness of the importance of spirituality in mental health contexts, a ‘religiosity gap’ exists in the difference in value placed on spirituality and religion by professionals compared with service users. This may be due to a lack of understanding about the complex ways people connect with spirituality within contemporary society and mental health contexts, and can result in people’s spiritual needs being neglected, dismissed or pathologised within clinical practice. The aim of this qualitative systematic review is to characterise the experiences of spirituality among adults with mental health difficulties in published qualitative research. Methods An electronic search of seven databases was conducted along with forward and backward citation searching, expert consultation and hand-searching of journals. 38 studies were included from 4944 reviewed papers. The review protocol was pre-registered (PROSPERO:CRD42017080566). Results A thematic synthesis identified six key themes: Meaning-making (sub-themes: Multiple explanations; Developmental journey; Destiny versus autonomy), Identity, Service-provision, Talk about it, Interaction with symptoms (sub-themes: Interactive meaning-making; Spiritual disruption) and Coping (sub-themes: Spiritual practices; Spiritual relationship; Spiritual struggles; Preventing suicide), giving the acronym MISTIC. Conclusions This qualitative systematic review provides evidence of the significant role spirituality plays in the lives of many people who experience mental health difficulties. It indicates the importance of mental health professionals being aware of and prepared to support the spiritual dimension of people using services. The production of a theory-based framework can inform efforts by health-providers to understand and address people’s spiritual needs as part of an integrated holistic approach towards care

    Calibration of the LOFAR low-band antennas using the Galaxy and a model of the signal chain

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    The LOw-Frequency ARray (LOFAR) is used to make precise measurements of radio emission from extensive air showers, yielding information about the primary cosmic ray. Interpreting the measured data requires an absolute and frequency-dependent calibration of the LOFAR system response. This is particularly important for spectral analyses, because the shape of the detected signal holds information about the shower development. We revisit the calibration of the LOFAR antennas in the range of 30 - 80 MHz. Using the Galactic emission and a detailed model of the LOFAR signal chain, we find an improved calibration that provides an absolute energy scale and allows for the study of frequency-dependent features in measured signals. With the new calibration, systematic uncertainties of 13% are reached, and comparisons of the spectral shape of calibrated data with simulations show promising agreement.Comment: 23 pages, 10 figure

    Plane-Symmetric Inhomogeneous Bulk Viscous Cosmological Models with Variable Λ\Lambda

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    A plane-symmetric non-static cosmological model representing a bulk viscous fluid distribution has been obtained which is inhomogeneous and anisotropic and a particular case of which is gravitationally radiative. Without assuming any {\it adhoc} law, we obtain a cosmological constant as a decreasing function of time. The physical and geometric features of the models are also discussed.Comment: 11 page
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