22,206 research outputs found
Bulk viscous Zel'dovich fluid model and it's asymptotic behavior
In this paper we have considered a flat FLRW universe with bulk viscous
Zel'dovich as the cosmic component. Being considered the bulk viscosity as per
the Eckart formalism, we have analyzed the evolution of the Hubble parameter
and constrained the model with the Type Ia Supernovae data thus extracting the
constant bulk viscous parameter and present Hubble parameter. Further we have
analyzed the scale factor, equation of state and deceleration parameter. The
model predicts the late time acceleration and is also compatible with the age
of the universe as given by the oldest globular clusters. We have also studied
the phase-space behavior of the model and found that a universe dominated by
bulk viscous Zel'dovich fluid is stable. But on the inclusion of radiation
component in addition to the Zel'dovich fluid, makes the model unstable. Hence,
even though the bulk viscous Zel'dovich fluid dominated universe is a feasible
one, the model as such failed to predict a prior radiation dominated phase.Comment: 14 pages, eight figure
Improving basic life support training for medical students
Mariam Lami, Pooja Nair, Karishma GadhviFaculty of Medicine, Imperial College, London, London, UKAbstract: Questions have been raised about basic life support (BLS) training in medical education. This article addresses the research evidence behind why BLS training is inadequate and suggests recommendations for improving BLS training for medical students.Keywords: medical education, basic life suppor
A specialized inventory problem in banks: optimizing retail sweeps
Deposits held at Federal Reserve Banks are an essential input to the business activity of most depository institutions in the United States. Managing these deposits is an important and complex inventory problem, for two reasons. First, Federal Reserve regulations require that depository institutions hold certain amounts of such deposits at the Federal Reserve Banks to satisfy statutory reserve requirements against customers* transaction accounts (demand deposits and other checkable deposits). Second, some inventory of such deposits is essential for banks to operate one of their core lines of business: furnishing payment services to households and firms. including wire transfers, ACH payments, and check clearing settlement. Because the Federal Reserve does not pay interest on such deposits used to satisfy statutory reserve requirements, banks seek to minimize their inventory of such deposits. In 1994, the banking industry introduced a new inventory management tool for such deposits, the retail deposit sweep program, which avoids the statutory requirement by reclassifying transaction deposits as savings deposits. In this analysis, we examine two algorithms for operating such sweeps programs within the limits of Federal Reserve regulations.Banks and banking ; Retail trade
Shark resources of India, with notes on biology of a few species
The annual production of elasmobranchs in India during 1982-83 to 1984-85 period was around 59,000 t, of which sharks accounted for 37500 t (64%). Tamil Nadu, Gujarat, Maharashtra and Kerala together take the bulk
of the catch. Of the 65 species reported from Indian waters, over 20 species (families Carcharhinidae and Sphymidae) contribute to the fishery. Feeding and breeding habits, intra-uterine embryos and growth characteristics of a few species are described here
A differential memristive synapse circuit for on-line learning in neuromorphic computing systems
Spike-based learning with memristive devices in neuromorphic computing
architectures typically uses learning circuits that require overlapping pulses
from pre- and post-synaptic nodes. This imposes severe constraints on the
length of the pulses transmitted in the network, and on the network's
throughput. Furthermore, most of these circuits do not decouple the currents
flowing through memristive devices from the one stimulating the target neuron.
This can be a problem when using devices with high conductance values, because
of the resulting large currents. In this paper we propose a novel circuit that
decouples the current produced by the memristive device from the one used to
stimulate the post-synaptic neuron, by using a novel differential scheme based
on the Gilbert normalizer circuit. We show how this circuit is useful for
reducing the effect of variability in the memristive devices, and how it is
ideally suited for spike-based learning mechanisms that do not require
overlapping pre- and post-synaptic pulses. We demonstrate the features of the
proposed synapse circuit with SPICE simulations, and validate its learning
properties with high-level behavioral network simulations which use a
stochastic gradient descent learning rule in two classification tasks.Comment: 18 Pages main text, 9 pages of supplementary text, 19 figures.
Patente
Seven year satellite observations of the mean structures and variabilities in the regional aerosol distribution over the oceanic areas around the Indian subcontinent
International audienceAerosol distribution over the oceanic regions around the Indian subcontinent and its seasonal and interannual variabilities are studied using the aerosol optical depth (AOD) derived from NOAA-14 and NOAA-16 AVHRR data for the period of November 1995?December 2003. The air-mass types over this region during the Asian summer monsoon season (June?September) are significantly different from those during the Asian dry season (November?April). Hence, the aerosol loading and its properties over these oceanic regions are also distinctly different in these two periods. During the Asian dry season, the Arabian Sea and Bay of Bengal are dominated by the transport of aerosols from Northern Hemispheric landmasses, mainly the Indian subcontinent, Southeast Asia and Arabia. This aerosol transport is rather weak in the early part of the dry season (November?January) compared to that in the later period (February?April). Large-scale transport of mineral dust from Arabia and the production of sea-salt aerosols, due to high surface wind speeds, contribute to the high aerosol loading over the Arabian Sea region during the summer monsoon season. As a result, the monthly mean AOD over the Arabian Sea shows a clear annual cycle with the highest values occurring in July. The AOD over the Bay of Bengal and the Southern Hemisphere Indian Ocean also displays an annual cycle with maxima during March and October, respectively. The amplitude of the annual variation is the largest in coastal Arabia and the least in the Southern Hemisphere Indian Ocean. The interannual variability in AOD is the largest over the Southeast Arabian Sea (seasonal mean AOD varies from 0.19 to 0.42) and the northern Bay of Bengal (seasonal mean AOD varies from 0.24 to 0.39) during the February?April period and is the least over the Southern Hemisphere Indian Ocean. This study also investigates the altitude regions and pathways of dominant aerosol transport by combining the AOD distribution with the atmospheric circulation. Keywords. Atmospheric composition and structure (Aerosols and particles) ? Meteorology and atmospheric dynamics (Climatology) ? Oceanography: physical (Ocean fog and aerosols
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