3,052 research outputs found

    BBH-LS: An algorithm for computing positional homologs using sequence and gene context similarity

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    10.1186/1752-0509-6-S1-S22BMC Systems Biology6SUPPL.1

    Postnatal growth and development pattern of camel calves

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    Trente-deux chameaux de Bactriane élevés dans des conditions traditionnelles d'élevage ont été suivis pour étudier leur croissance post-natale et leur profil de développement. Treize mesures corporelles linéaires ont été faites à trente jours d'intervalle depuis la naissance jusqu'au 420 ème jour. Les taux moyens de croissance pour la hauteur, le tour de poitrine, la longueur, la circonférence de l'os canon, la profondeur et la largeur du poitrail, la longueur et la largeur de la croupe, la longueur des pattes, la longueur et la largeur de la tête et la longueur du cou ont été évalués. Les résultats ont montré que, dans une large mesure, les différentes dimensions corporelles avaient un profil de maturité uniforme et que leur hiérarchie tendait à rester constante pendant toute la période d'observation. Les taux de croissance rapide correspondaient à un allaitement maternel satisfaisant. Le profil de croissance du poids vif suivait la courbe de la plupart des mammifères. Cependant la croissance a été plus rapide au cours des sept premiers mois et le gain de poids moyen quotidien (gmq) le plus important a été constaté au cours du 3e mois, avec une moyenne de 0,782 ± 0,349 kg. Un gmq négatif a été observé entre le 1Oe et le 11e mois avec une moyenne de -0,1677 ± 0,19 kg pour les mâles et de -0,006 ± 0,24 kg pour les femelles, lorsque la mère entrait en période de reproduction et que la production laitière chutait. Le gmq moyen sur 420 jours a été de 0,3846 ± 0,2895 kgd-1. Les courbes de croissance standardisées ont permit de déduire le degré de maturité en termes de poids vif et d'âge. (Résumé d'auteur

    GaN hemispherical micro-cavities

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    Faraday instability on viscous ferrofluids in a horizontal magnetic field: Oblique rolls of arbitrary orientation

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    A linear stability analysis of the free surface of a horizontally unbounded ferrofluid layer of arbitrary depth subjected to vertical vibrations and a horizontal magnetic field is performed. A nonmonotonic dependence of the stability threshold on the magnetic field is found at high frequencies of the vibrations. The reasons of the decrease of the critical acceleration amplitude caused by a horizontal magnetic field are discussed. It is revealed that the magnetic field can be used to select the first unstable pattern of Faraday waves. In particular, a rhombic pattern as a superposition of two different oblique rolls can occur. A scaling law is presented which maps all data into one graph for the tested range of viscosities, frequencies, magnetic fields and layer thicknesses.Comment: 8 pages, 6 figures, RevTex

    Fullerene graphs have exponentially many perfect matchings

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    A fullerene graph is a planar cubic 3-connected graph with only pentagonal and hexagonal faces. We show that fullerene graphs have exponentially many perfect matchings.Comment: 7 pages, 3 figure

    Parametrically Excited Surface Waves: Two-Frequency Forcing, Normal Form Symmetries, and Pattern Selection

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    Motivated by experimental observations of exotic standing wave patterns in the two-frequency Faraday experiment, we investigate the role of normal form symmetries in the pattern selection problem. With forcing frequency components in ratio m/n, where m and n are co-prime integers, there is the possibility that both harmonic and subharmonic waves may lose stability simultaneously, each with a different wavenumber. We focus on this situation and compare the case where the harmonic waves have a longer wavelength than the subharmonic waves with the case where the harmonic waves have a shorter wavelength. We show that in the former case a normal form transformation can be used to remove all quadratic terms from the amplitude equations governing the relevant resonant triad interactions. Thus the role of resonant triads in the pattern selection problem is greatly diminished in this situation. We verify our general results within the example of one-dimensional surface wave solutions of the Zhang-Vinals model of the two-frequency Faraday problem. In one-dimension, a 1:2 spatial resonance takes the place of a resonant triad in our investigation. We find that when the bifurcating modes are in this spatial resonance, it dramatically effects the bifurcation to subharmonic waves in the case of forcing frequencies are in ratio 1/2; this is consistent with the results of Zhang and Vinals. In sharp contrast, we find that when the forcing frequencies are in ratio 2/3, the bifurcation to (sub)harmonic waves is insensitive to the presence of another spatially-resonant bifurcating mode.Comment: 22 pages, 6 figures, late

    Novel tau filament fold in chronic traumatic encephalopathy encloses hydrophobic molecules

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    Chronic traumatic encephalopathy (CTE) is a neurodegenerative tauopathy that is associated with repetitive head impacts or exposure to blast waves. First described as punch-drunk syndrome and dementia pugilistica in retired boxers1-3, CTE has since been identified in former participants of other contact sports, ex-military personnel and after physical abuse4-7. No disease-modifying therapies currently exist, and diagnosis requires an autopsy. CTE is defined by an abundance of hyperphosphorylated tau protein in neurons, astrocytes and cell processes around blood vessels8,9. This, together with the accumulation of tau inclusions in cortical layers II and III, distinguishes CTE from Alzheimer's disease and other tauopathies10,11. However, the morphologies of tau filaments in CTE and the mechanisms by which brain trauma can lead to their formation are unknown. Here we determine the structures of tau filaments from the brains of three individuals with CTE at resolutions down to 2.3 Å, using cryo-electron microscopy. We show that filament structures are identical in the three cases but are distinct from those of Alzheimer's and Pick's diseases, and from those formed in vitro12-15. Similar to Alzheimer's disease12,14,16-18, all six brain tau isoforms assemble into filaments in CTE, and residues K274-R379 of three-repeat tau and S305-R379 of four-repeat tau form the ordered core of two identical C-shaped protofilaments. However, a different conformation of the β-helix region creates a hydrophobic cavity that is absent in tau filaments from the brains of patients with Alzheimer's disease. This cavity encloses an additional density that is not connected to tau, which suggests that the incorporation of cofactors may have a role in tau aggregation in CTE. Moreover, filaments in CTE have distinct protofilament interfaces to those of Alzheimer's disease. Our structures provide a unifying neuropathological criterion for CTE, and support the hypothesis that the formation and propagation of distinct conformers of assembled tau underlie different neurodegenerative diseases

    Neutron/proton ratio of nucleon emissions as a probe of neutron skin

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    The dependence between neutron-to-proton yield ratio (RnpR_{np}) and neutron skin thickness (δnp\delta_{np}) in neutron-rich projectile induced reactions is investigated within the framework of the Isospin-Dependent Quantum Molecular Dynamics (IQMD) model. The density distribution of the Droplet model is embedded in the initialization of the neutron and proton densities in the present IQMD model. By adjusting the diffuseness parameter of neutron density in the Droplet model for the projectile, the relationship between the neutron skin thickness and the corresponding RnpR_{np} in the collisions is obtained. The results show strong linear correlation between RnpR_{np} and δnp\delta_{np} for neutron-rich Ca and Ni isotopes. It is suggested that RnpR_{np} may be used as an experimental observable to extract δnp\delta_{np} for neutron-rich nuclei, which is very significant to the study of the nuclear structure of exotic nuclei and the equation of state (EOS) of asymmetric nuclear matter.Comment: 7 pages, 5 figures; accepted by Phys. Lett.

    Universality and scaling study of the critical behavior of the two-dimensional Blume-Capel model in short-time dynamics

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    In this paper we study the short-time behavior of the Blume-Capel model at the tricritical point as well as along the second order critical line. Dynamic and static exponents are estimated by exploring scaling relations for the magnetization and its moments at early stage of the dynamic evolution. Our estimates for the dynamic exponents, at the tricritical point, are z=2.215(2)z= 2.215(2) and θ=0.53(2)\theta= -0.53(2).Comment: 12 pages, 9 figure
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