862 research outputs found

    Biogeographic Variation in the Diet and Behaviour of Cercopithecus mitis

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    Primate species are characterised by variation in foraging behaviour and dietary composition across their geographic range. Here we examine how ecological conditions account for variation in the behavioural ecology of a widespread arboreal guenon, Cercopithecus mitis. Although substantial variation existed in time budgets, group size, home range and day journey length, clear biogeographic patterns were not apparent. In contrast, dietary variation was correlated with underlying climatic conditions. Temperature seasonality, which tends to increase with latitude, was significantly positively related to the proportion of fruit in the diet and negatively related to the proportion of animal matter. Both dietary components were ‘preferred' foods, with the variability between populations reflecting the availability of different food types across their geographic range. Although we found no significant relationships between climate and the proportion of leaves in the diet, the ability for C. mitis to vary its diet to include a diversity of food types, and to incorporate a significant proportion of leaves when preferred sources are scarce, likely underpins its ability to survive across such a large distribution

    Gravitational anomalies in a dispersive approach

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    The gravitational anomalies in two dimensions, specifically the Einstein anomaly and the Weyl anomaly, are fully determined by means of dispersion relations. In this approach the anomalies originate from the peculiar infrared feature of the imaginary part of the relevant formfactor which approaches a δ\delta-function singularity at zero momentum squared when m0m \to 0.Comment: 10 page

    mTORtuous effect on the elastic heart

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    Both during normal physiological development as well as in the face of cardiac stress, the heart exhibits enormous plasticity in growth, remodeling, and atrophy. Central to this adaptive ability is the heart’s metabolic capacity to react quickly both anabolically and catabolically in order to maintain cardiac output. In response to hemodynamic stress, the heart adapts to maintain overall contractile function via pathological remodeling that often includes cardiomyocyte hypertrophy as well as changes in cardiomyocyte metabolism that eventually lead to contractile dysfunction and heart failure. It is unclear as to whether the metabolic changes that accompany pathological hypertrophy are adaptive or maladaptive; however, as in most complex biological systems, the answer likely resides somewhere in the middle. Goodwin et al. demonstrated in 1998 that hemodynamic stress increases carbohydrate use for ATP generation and induces cardiac remodeling. Numerous subsequent studies have attributed the change in metabolism and cardiac remodeling to activation of the mammalian (or mechanistic) target of rapamycin (mTOR), a kinase that is a primary regulator of myocardial protein synthesis. Recent experimental models that manipulate cardiac metabolism and mTOR signaling have provided new insights into the relationship between metabolic and structural remodeling (reviewed in detail by Kundu et al.). One hopes that such models will identify metabolic changes that precede remodeling in order to find therapeutic targets for cardiac disease

    Thermodynamics of non-local materials: extra fluxes and internal powers

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    The most usual formulation of the Laws of Thermodynamics turns out to be suitable for local or simple materials, while for non-local systems there are two different ways: either modify this usual formulation by introducing suitable extra fluxes or express the Laws of Thermodynamics in terms of internal powers directly, as we propose in this paper. The first choice is subject to the criticism that the vector fluxes must be introduced a posteriori in order to obtain the compatibility with the Laws of Thermodynamics. On the contrary, the formulation in terms of internal powers is more general, because it is a priori defined on the basis of the constitutive equations. Besides it allows to highlight, without ambiguity, the contribution of the internal powers in the variation of the thermodynamic potentials. Finally, in this paper, we consider some examples of non-local materials and derive the proper expressions of their internal powers from the power balance laws.Comment: 16 pages, in press on Continuum Mechanics and Thermodynamic

    Goserelin, as an ovarian protector during (neo)adjuvant breast cancer chemotherapy, prevents long term altered bone turnover

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    Background: The Ovarian Protection Trial In Premenopausal Breast Cancer Patients “OPTION” trial (NCT00427245) was a prospective, multicenter, randomised, open label study evaluating the frequency of primary ovarian insufficiency (POI) at 12 months in women randomised to 6–8 cycles of (neo)adjuvant chemotherapy (CT) þ/ goserelin (G). Here we report the results of a secondary endpoint analysis of the effects of CTþ/-G on markers of bone turnover. Methods: Serum for bone alkaline phosphatase (BALP) and urine for N-terminal telopeptide (NTX) were collected at baseline, 6, 12, 18, 24 and 36 months. Changes in median levels of bone turnover markers were evaluated for the overall population, according to age stratification at randomisation (r40 vs 440 years) and with exploratory analysis according to POI rates at 12 months. Results: In the overall population, there was a significant increase in NTX at 6 months compared to baseline in patients treated with CTþG (40.81 vs 57.82 p¼0.0074) with normalisation of levels thereafter. BALP was significantly increased compared to baseline at 6 months and 12 months in those receiving CTþG, but normalised thereafter. BALP remained significantly higher compared to baseline at 12, 24 and 36 months in patients receiving CT, resulting in a significant difference between treatment groups at 36 months (CTþG 5.845 vs CT 8.5 p¼0.0006). These changes were predominantly seen in women 440 years. Women with POI at 12 months showed altered bone formation compared to baseline levels for a longer duration than women who maintained menses. Conclusion: Addition of G to CT increases bone turnover during treatment with normalisation after cessation of treatment suggesting G may offer sufficient ovarian protection against CT induced POI to negate longstanding altered bone turnover associated with POI

    Pressure and linear heat capacity in the superconducting state of thoriated UBe13

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    Even well below Tc, the heavy-fermion superconductor (U,Th)Be13 has a large linear term in its specific heat. We show that under uniaxial pressure, the linear heat capacity increases in magnitude by more than a factor of two. The change is reversible and suggests that the linear term is an intrinsic property of the material. In addition, we find no evidence of hysteresis or of latent heat in the low-temperature and low-pressure portion of the phase diagram, showing that all transitions in this region are second order.Comment: 5 pages, 4 figure

    Virtual Black Holes

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    One would expect spacetime to have a foam-like structure on the Planck scale with a very high topology. If spacetime is simply connected (which is assumed in this paper), the non-trivial homology occurs in dimension two, and spacetime can be regarded as being essentially the topological sum of S2×S2S^2\times S^2 and K3K3 bubbles. Comparison with the instantons for pair creation of black holes shows that the S2×S2S^2\times S^2 bubbles can be interpreted as closed loops of virtual black holes. It is shown that scattering in such topological fluctuations leads to loss of quantum coherence, or in other words, to a superscattering matrix $\$ that does not factorise into an SS matrix and its adjoint. This loss of quantum coherence is very small at low energies for everything except scalar fields, leading to the prediction that we may never observe the Higgs particle. Another possible observational consequence may be that the θ\theta angle of QCD is zero without having to invoke the problematical existence of a light axion. The picture of virtual black holes given here also suggests that macroscopic black holes will evaporate down to the Planck size and then disappear in the sea of virtual black holes.Comment: 24p, LaTeX, 3 postscript figures included with epsf sent in a seperate uuencoded fil

    A complete solution of a Constrained System: SUSY Monopole Quantum Mechanics

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    We solve the quantum mechanical problem of a charged particle on S^2 in the background of a magnetic monopole for both bosonic and supersymmetric cases by constructing Hilbert space and realizing the fundamental operators obeying complicated Dirac bracket relations in terms of differential operators. We find the complete energy eigenfunctions. Using the lowest energy eigenstates we count the number of degeneracies and examine the supersymmetric structure of the ground states in detail.Comment: 20 pages including the title, prepared in JHEP forma

    Superconformal Multi-Black Hole Moduli Spaces in Four Dimensions

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    Quantum mechanics on the moduli space of N supersymmetric Reissner-Nordstrom black holes is shown to admit 4 supersymmetries using an unconventional supermultiplet which contains 3N bosons and 4N fermions. A near-horizon limit is found in which the quantum mechanics of widely separated black holes decouples from that of strongly-interacting, near-coincident black holes. This near-horizon theory is shown to have an enhanced D(2,1;0) superconformal symmetry. The bosonic symmetries are SL(2,R) conformal symmetry and SU(2)xSU(2) R-symmetry arising from spatial rotations and the R-symmetry of N=2 supergravity.Comment: 23 pages, harvmac. v2: many typos fixe
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