482 research outputs found
Search for a circum-planetary material and orbital period variations of short-period Kepler exoplanet candidates
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
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 Zr to the first excited state of Mo
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 Zr to the excited state of
Mo at 871.1 keV is studied using a low background 230 cm 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 to the excited state of is y at 90% C.L., an improvement by a factor of
4 over the existing experimental limit at 90\% C.L. The sensitivity is
estimated to be 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
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
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
THE PROMOTION OF EUROPEAN ECOSOCIAL MODEL TO THE DEVELOPMENT OF HUNGARIAN AGRICULTURAL EMPLOYMENT AND RURAL AREAS
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
Footprint traversal by ATP-dependent chromatin remodeler motor
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 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
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