470 research outputs found

    Search for a circum-planetary material and orbital period variations of short-period Kepler exoplanet candidates

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    A unique short-period Mercury-size Kepler exoplanet candidate KIC012557548b has been discovered recently by Rappaport et al. (2012). This object is a transiting disintegrating exoplanet with a circum-planetary material - comet-like tail. Close-in exoplanets, like KIC012557548b, are subjected to the greatest planet-star interactions. This interaction may have various forms. In certain cases it may cause formation of the comet-like tail. Strong interaction with the host star, and/or presence of an additional planet may lead to variations in the orbital period of the planet. Our main aim is to search for comet-like tails similar to KIC012557548b and for long-term orbital period variations. We are curious about frequency of comet-like tail formation among short-period Kepler exoplanet candidates. We concentrate on a sample of 20 close-in candidates with a period similar to KIC012557548b from the Kepler mission.Comment: 19 pages, 75 figures, AN accepte

    Broadband potential optimisation of a full scale acoustic metawindow performance

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    Noise control and airflow in duct-like systems are among some of the most interesting applications to conjugate AMMs innovation and sustainability. Specifically applied to the built environment, they opened up a new field of research supporting indoor wellbeing, sanitised environments, and public activities. Previous research conducted by the authors has proved AMM based window to be a resourceful way to address both natural ventilation and reduce the incoming noise propagation; however, the effective spectral range did not cover lower frequencies (50-350 Hz). For this reason, in the presented paper, implementation in the AMM unit geometry was performed over a full-scale acoustic metawindow (AMW). The resonating volume has been enhanced (by 200% of the original one) and coupled with a set of lateral flanks. Numerical analysis through FEM proved that on a range of opening ratio from 3 to 33%, the TL related to the window is improved overall of the 70% on the frequency range from 50 to 350 Hz. Such results encourage the use of new AMMs ergonomic windows in place of standard ones to achieve both natural ventilation and noise attenuation from 50 to 5k Hz, being resourceful for domestic, sanitary, and public applications

    New limit for the half-life of double beta decay of 94^{94}Zr to the first excited state of 94^{94}Mo

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    Neutrinoless Double Beta Decay is a phenomenon of fundamental interest in particle physics. The decay rates of double beta decay transitions to the excited states can provide input for Nuclear Transition Matrix Element calculations for the relevant two neutrino double beta decay process. It can be useful as supplementary information for the calculation of Nuclear Transition Matrix Element for the neutrinoless double beta decay process. In the present work, double beta decay of 94^{94}Zr to the 21+2^{+}_{1} excited state of 94^{94}Mo at 871.1 keV is studied using a low background \sim 230 cm3^3 HPGe detector. No evidence of this decay was found with a 232 g.y exposure of natural Zirconium. The lower half-life limit obtained for the double beta decay of 94Zr\rm^{94}Zr to the 21+2^{+}_{1} excited state of 94Mo\rm^{94}Mo is T1/2(0ν+2ν)>3.4×1019T_{1/2} (0\nu + 2\nu)> 3.4 \times 10^{19} y at 90% C.L., an improvement by a factor of \sim 4 over the existing experimental limit at 90\% C.L. The sensitivity is estimated to be T1/2(0ν+2ν)>2.0×1019T_{1/2} (0\nu + 2\nu) > 2.0\times10^{19} y at 90% C.L. using the Feldman-Cousins method.Comment: 11 pages, 7 figures, Accepted in Eur. Phys. J.

    The mechanism of CO2 hydration: a porous metal oxide nanocapsule catalyst can mimic the biological carbonic anhydrase role

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    Bandeira NAG, Garai S, Müller A, Bo C. The mechanism of CO2 hydration: a porous metal oxide nanocapsule catalyst can mimic the biological carbonic anhydrase role. Chemical Communications. 2015;51(85):15596-15599.The mechanism for the hydration of CO2 within a Keplerate nanocapsule is presented. A network of hydrogen bonds across the water layers in the first metal coordination sphere facilitates the proton abstraction and nucleophilic addition of water. The highly acidic properties of the polyoxometalate cluster are crucial for explaining the catalysed hydration

    Stochastic kinetics of ribosomes: single motor properties and collective behavior

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    Synthesis of protein molecules in a cell are carried out by ribosomes. A ribosome can be regarded as a molecular motor which utilizes the input chemical energy to move on a messenger RNA (mRNA) track that also serves as a template for the polymerization of the corresponding protein. The forward movement, however, is characterized by an alternating sequence of translocation and pause. Using a quantitative model, which captures the mechanochemical cycle of an individual ribosome, we derive an {\it exact} analytical expression for the distribution of its dwell times at the successive positions on the mRNA track. Inverse of the average dwell time satisfies a ``Michaelis-Menten-like'' equation and is consistent with the general formula for the average velocity of a molecular motor with an unbranched mechano-chemical cycle. Extending this formula appropriately, we also derive the exact force-velocity relation for a ribosome. Often many ribosomes simultaneously move on the same mRNA track, while each synthesizes a copy of the same protein. We extend the model of a single ribosome by incorporating steric exclusion of different individuals on the same track. We draw the phase diagram of this model of ribosome traffic in 3-dimensional spaces spanned by experimentally controllable parameters. We suggest new experimental tests of our theoretical predictions.Comment: Final published versio

    Footprint traversal by ATP-dependent chromatin remodeler motor

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    ATP-dependent chromatin remodeling enzymes (CRE) are bio-molecular motors in eukaryotic cells. These are driven by a chemical fuel, namely, adenosine triphosphate (ATP). CREs actively participate in many cellular processes that require accessibility of specific segments of DNA which are packaged as chromatin. The basic unit of chromatin is a nucleosome where 146 bp \sim 50 nm of a double stranded DNA (dsDNA) is wrapped around a spool formed by histone proteins. The helical path of histone-DNA contact on a nucleosome is also called "footprint". We investigate the mechanism of footprint traversal by a CRE that translocates along the dsDNA. Our two-state model of a CRE captures effectively two distinct chemical (or conformational) states in the mechano-chemical cycle of each ATP-dependent CRE. We calculate the mean time of traversal. Our predictions on the ATP-dependence of the mean traversal time can be tested by carrying out {\it in-vitro} experiments on mono-nucleosomes.Comment: 11 pages, 12 figures; minor revision of tex

    THE PROMOTION OF EUROPEAN ECOSOCIAL MODEL TO THE DEVELOPMENT OF HUNGARIAN AGRICULTURAL EMPLOYMENT AND RURAL AREAS

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    In addition to the European agricultural productivity tasks so-called ecosocial services being born locally, have to be worked out, cannot be imported. The agriculture and the rural population have to be compensated. For the above mentioned the perception and demands of the aforesaid led to the establishment of the multifunctional European agricultural model, the reform of the common agricultural and regional policy. One of the aims of the study is the objective analysis of the situation, the other is the environmental approach of the complex social – economic possibilities of agriculture and regional development
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