8,400 research outputs found
Effect of hyperon-hyperon interaction on bulk viscosity and r-mode instability in neutron stars
We investigate the effect of hyperon matter including hyperon-hyperon
interaction on bulk viscosity. Equations of state are constructed within the
framework of a relativistic field theoretical model where baryon-baryon
interaction is mediated by the exchange of scalar and vector mesons.
Hyperon-hyperon interaction is also taken into account by the exchange of two
strange mesons. This interaction results in a smaller maximum mass neutron star
compared with the case without the interaction. The coefficient of bulk
viscosity due to the non-leptonic weak process is determined by these equations
of state. The interacting hyperon matter reduces the bulk viscosity coefficient
in a neutron star interior compared with the no interaction case. The r-mode
instability is more effectively suppressed in hyperon-hyperon interaction case
than that without the interaction.Comment: 25 pages, 10 figures; two new figures added and results and
discussion section revised; final version to appear in PR
Interpreting the bounds on Solar Dark Matter induced muons at Super-Kamiokande in the light of CDMS results
We consider the recent limits on dark matter - nucleon elastic scattering
cross section from the analysis of CDMS II collaboration using the two signal
events observed in CDMS experiment. With these limits we try to interpret the
Super-Kamiokande (SK) bounds on the detection rates of up-going muons induced
by the neutrinos that are produced in the sun from the decay of annihilation
products of dark matter (WIMPs) captured in the solar core. Calculated rates of
up-going muons for different annihilation channels at SK using CDMS bounds are
found to be orders below the predicted upper limits of such up-going muon rates
at SK. Thus there exists room for enhancement (boost) of the calculated rates
using CDMS limits for interpreting SK bounds. Such a feature is expected to
represent the PAMELA data with the current CDMS limits. We also show the
dependence of such a possible enhancement factor (boost) on WIMP mass for
different WIMP annihilation channels.Comment: 7 pages, 6 figure
Universality in Complex Networks: Random Matrix Analysis
We apply random matrix theory to complex networks. We show that nearest
neighbor spacing distribution of the eigenvalues of the adjacency matrices of
various model networks, namely scale-free, small-world and random networks
follow universal Gaussian orthogonal ensemble statistics of random matrix
theory. Secondly we show an analogy between the onset of small-world behavior,
quantified by the structural properties of networks, and the transition from
Poisson to Gaussian orthogonal ensemble statistics, quantified by Brody
parameter characterizing a spectral property. We also present our analysis for
a protein-protein interaction network in budding yeast.Comment: 4+ pages, 4 figures, to appear in PRE, major change in the paper
including titl
Statistical Inference and the Plethora of Probability Paradigms: A Principled Pluralism
The major competing statistical paradigms share a common remarkable but unremarked thread: in many of their inferential applications, different probability interpretations are combined. How this plays out in different theories of inference depends on the type of question asked. We distinguish four question types: confirmation, evidence, decision, and prediction. We show that Bayesian confirmation theory mixes what are intuitively “subjective” and “objective” interpretations of probability, whereas the likelihood-based account of evidence melds three conceptions of what constitutes an “objective” probability
Quantum coherence and sensitivity of avian magnetoreception
Migratory birds and other species have the ability to navigate by sensing the
geomagnetic field. Recent experiments indicate that the essential process in
the navigation takes place in bird's eye and uses chemical reaction involving
molecular ions with unpaired electron spins (radical pair). Sensing is achieved
via geomagnetic-dependent dynamics of the spins of the unpaired electrons. Here
we utilize the results of two behavioral experiments conducted on European
Robins to argue that the average life-time of the radical pair is of the order
of a microsecond and therefore agrees with experimental estimations of this
parameter for cryptochrome --- a pigment believed to form the radical pairs. We
also found a reasonable parameter regime where sensitivity of the avian compass
is enhanced by environmental noise, showing that long coherence time is not
required for navigation and may even spoil it.Comment: 6+ pages, 2+4 figures, new results adde
A Concise Account on the Properties of CNT-Reinforced Epoxy Composites based on some Select References
Recently it has been reported in the technical literature that carbon nanotubes (CNTs) have distinct effects on thermal, mechanical and electric properties of epoxy resins. Compared to single-walled nanotubes (SWCNT), multiwalled nanotubes (MWCNT) apparently show greater improvements. The maximum aspect ratio (L/D) of CNT is reportedly as high as 138,000,000. In addition, the carbon nanotubes when treated with surface modifier to generate functional groups on their surface can afford to provide better improvement of the properties of the epoxy based CNT-particulate composite system. There are a number of factors that can influence the properties of epoxy-CNT systems. This paper examined the technical contents from selective references and made an attempt to highlight the general understanding of the properties and performance of epoxy – CNT particulate composite systems.Defence Science Journal, Vol. 64, No. 3, May 2014, pp.303-308, DOI:http://dx.doi.org/10.14429/dsj.64.7330
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