1,342 research outputs found

    Evaluating Mood Changes in Response to Anthropogenic Noise with a Response-Slowing Task in Three Species of Zoo-housed Primates

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    In the zoo environment, anthropogenic noise is common as sound levels fluctuate due to visitors, construction, habitat design, and special events. In this study, changes in the mood of three species of zoo-housed primates in response to a loud annual event were evaluated with the response-slowing paradigm. In this paradigm, animals experiencing anxiety slow responses on simple cognitive tasks when emotional content is displayed. Following a previously validated approach, we measured latencies to touch potentially threatening (conspecific faces with directed gaze) and non-threatening (conspecific faces with averted gaze) images overlaid on a grey square, relative to neutral control images (grey squares only) on a touchscreen. In Experiment 1, four Japanese macaques (Macaca fuscata) were tested in two conditions: during a baseline (non-stressful) period and opportunistically during three days during which loud jets frequently flew overhead. Results indicated a significant effect of condition, with an increase in latency to touch images of conspecific faces relative to control images during the days of the loud event. In Experiment 2, chimpanzees (Pan troglodytes, n = 4) and western lowland gorillas (Gorilla gorilla gorilla, n = 2) were tested during the same loud event following a similar methodology. The results revealed subtle changes across conditions; however, this was likely driven by the apes increasing their response speed to face stimuli relative to control stimuli over time (habituation). These findings suggest that the macaques, but not the apes, underwent detectable affective changes during the loud event. With additional development, this relatively simple paradigm may be an effective and feasible way to evaluate real-time changes in the mood of zoo-housed animals

    Lion populations may be declining in Africa but not as Bauer et al. suggest

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    Black Hole Thermodynamics and Massive Gravity

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    We consider the generalized laws of thermodynamics in massive gravity. Making use of explicit black hole solutions, we devise black hole merger processes in which i) total entropy of the system decreases ii) the zero-temperature extremal black hole is created. Thus, both second and third laws of thermodynamics are violated. In both cases, the violation can be traced back to the presence of negative-mass black holes, which, in turn, is related to the violation of the null energy condition. The violation of the third law of thermodynamics implies, in particular, that a naked singularity may be created as a result of the evolution of a singularity-free state. This may signal a problem in the model, unless the creation of the negative-mass black holes from positive-mass states can be forbidden dynamically or the naked singularity may somehow be resolved in a full quantum theory.Comment: 15 pages, 4 figures; v2:Style changed to JHEP. Discussion added in the conclusions. Revised version to match published versio

    Evidence of a metabolic memory to early-life dietary restriction in male C57BL/6 mice

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    <p>Background: Dietary restriction (DR) extends lifespan and induces beneficial metabolic effects in many animals. What is far less clear is whether animals retain a metabolic memory to previous DR exposure, that is, can early-life DR preserve beneficial metabolic effects later in life even after the resumption of ad libitum (AL) feeding. We examined a range of metabolic parameters (body mass, body composition (lean and fat mass), glucose tolerance, fed blood glucose, fasting plasma insulin and insulin-like growth factor 1 (IGF-1), insulin sensitivity) in male C57BL/6 mice dietary switched from DR to AL (DR-AL) at 11 months of age (mid life). The converse switch (AL-DR) was also undertaken at this time. We then compared metabolic parameters of the switched mice to one another and to age-matched mice maintained exclusively on an AL or DR diet from early life (3 months of age) at 1 month, 6 months or 10 months post switch.</p> <p>Results: Male mice dietary switched from AL-DR in mid life adopted the metabolic phenotype of mice exposed to DR from early life, so by the 10-month timepoint the AL-DR mice overlapped significantly with the DR mice in terms of their metabolic phenotype. Those animals switched from DR-AL in mid life showed clear evidence of a glycemic memory, with significantly improved glucose tolerance relative to mice maintained exclusively on AL feeding from early life. This difference in glucose tolerance was still apparent 10 months after the dietary switch, despite body mass, fasting insulin levels and insulin sensitivity all being similar to AL mice at this time.</p> <p>Conclusions: Male C57BL/6 mice retain a long-term glycemic memory of early-life DR, in that glucose tolerance is enhanced in mice switched from DR-AL in mid life, relative to AL mice, even 10 months following the dietary switch. These data therefore indicate that the phenotypic benefits of DR are not completely dissipated following a return to AL feeding. The challenge now is to understand the molecular mechanisms underlying these effects, the time course of these effects and whether similar interventions can confer comparable benefits in humans.</p&gt

    Lumbar spine and total-body dual-energy X-ray absorptiometry in children with severe neurological impairment and intellectual disability: a pilot study of artefacts and disrupting factors

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    Background Children with severe neurological impairment and intellectual disability (ID) are susceptible for developing low bone mineral density (BMD) and fractures. BMD is generally measured with dual-energy X-ray absorptiometry (DXA). Objective To describe the occurrence of factors that may influence the feasibility of DXA and the accuracy of DXA outcome in children with severe neurological impairment and ID. Materials and methods Based on literature and expert opinion, a list of disrupting factors was developed. Occurrence of these factors was assessed in 27 children who underwent DXA measurement. Results Disrupting factors that occurred most frequently were movement during measurement (82%), aberrant body composition (67%), small length for age (56%) and scoliosis (37%). The number of disrupting factors per child was mean 5.3 (range 1-8). No correlation was found between DXA outcomes and the number of disrupting factors. Conclusion Factors that may negatively influence the accuracy of DXA outcome are frequently present in children with severe neurological impairment and ID. No systematic deviation of DXA outcome in coherence with the amount of disrupting factors was found, but physicians should be aware of the possible influence of disrupting factors on the accuracy of DXA

    Effective Theory Approach to the Spontaneous Breakdown of Lorentz Invariance

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    We generalize the coset construction of Callan, Coleman, Wess and Zumino to theories in which the Lorentz group is spontaneously broken down to one of its subgroups. This allows us to write down the most general low-energy effective Lagrangian in which Lorentz invariance is non-linearly realized, and to explore the consequences of broken Lorentz symmetry without having to make any assumptions about the mechanism that triggers the breaking. We carry out the construction both in flat space, in which the Lorentz group is a global spacetime symmetry, and in a generally covariant theory, in which the Lorentz group can be treated as a local internal symmetry. As an illustration of this formalism, we construct the most general effective field theory in which the rotation group remains unbroken, and show that the latter is just the Einstein-aether theory.Comment: 45 pages, no figures
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