13,452 research outputs found
Some Paranormed Difference Sequence Spaces of Order Derived by Generalized Means and Compact Operators
We have introduced a new sequence space
combining by using generalized means and difference operator of order . We
have shown that the space is complete under some
suitable paranorm and it has Schauder basis. Furthermore, the -,
-, - duals of this space is computed and also obtained necessary
and sufficient conditions for some matrix transformations from to . Finally, we obtained some identities or
estimates for the operator norms and the Hausdorff measure of noncompactness of
some matrix operators on the BK space by
applying the Hausdorff measure of noncompactness.Comment: Please withdraw this paper as there are some logical gap in some
results. 20 pages. arXiv admin note: substantial text overlap with
arXiv:1307.5883, arXiv:1307.5817, arXiv:1307.588
Primordial Non-Gaussianity in the Cosmic Microwave Background
In the last few decades, advances in observational cosmology have given us a
standard model of cosmology. We know the content of the universe to within a
few percent. With more ambitious experiments on the way, we hope to move beyond
the knowledge of what the universe is made of, to why the universe is the way
it is. In this review paper we focus on primordial non-Gaussianity as a probe
of the physics of the dynamics of the universe at the very earliest moments. We
discuss 1) theoretical predictions from inflationary models and their
observational consequences in the cosmic microwave background (CMB)
anisotropies; 2) CMB--based estimators for constraining primordial
non-Gaussianity with an emphasis on bispectrum templates; 3) current
constraints on non-Gaussianity and what we can hope to achieve in the near
future; and 4) non-primordial sources of non-Gaussianities in the CMB such as
bispectrum due to second order effects, three way cross-correlation between
primary-lensing-secondary CMB, and possible instrumental effects.Comment: 27 pages, 8 figures; Invited Review for the Journal "Advances in
Astronomy"; references adde
Renormalization group approach to chiral symmetry breaking in graphene
We investigate the development of a gapped phase in the field theory of Dirac
fermions in graphene with long-range Coulomb interaction. In the large-N
approximation, we show that the chiral symmetry is only broken below a critical
number of two-component Dirac fermions , that is exactly half
the value found in quantum electrodynamics in 2+1 dimensions. Adopting
otherwise a ladder approximation, we give evidence of the existence of a
critical coupling at which the anomalous dimension of the order parameter of
the transition diverges. This result is consistent with the observation that
chiral symmetry breaking may be driven by the long-range Coulomb interaction in
the Dirac field theory, despite the divergent scaling of the Fermi velocity in
the low-energy limit.Comment: 6 pages, 4 figures, extended version with technical detail
Force induced melting of the constrained DNA
We develop a simple model to study the effects of an applied force on the
melting of a double stranded DNA (dsDNA). Using this model, we could study the
stretching, unzipping, rupture and slippage like transition in a dsDNA.
We show that in absence of an applied force, the melting temperature and the
melting profile of dsDNA strongly depend on the constrained imposed on the ends
of dsDNA. The nature of the phase boundary which separates the zipped and the
open state for the shearing like transition is remarkably different than the
DNA unzippingComment: 8 pages, 10 figure
Fatiguing Effects of Indirect Vibration Stimulation in Upper Limb Muscles- pre, post and during Isometric Contractions Superimposed on Upper Limb Vibration
© 2019 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/ , which permits unrestricted use, provided the original author and source are credited.Whole-body vibration and upper limb vibration (ULV) continue to gain popularity as exercise intervention for rehabilitation and sports applications. However, the fatiguing effects of indirect vibration stimulation are not yet fully understood. We investigated the effects of ULV stimulation superimposed on fatiguing isometric contractions using a purpose developed upper limb stimulation device. Thirteen healthy volunteers were exposed to both ULV superimposed to fatiguing isometric contractions (V) and isometric contractions alone Control (C). Both Vibration (V) and Control (C) exercises were performed at 80% of the maximum voluntary contractions. The stimulation used was 30 Hz frequency of 0.4 mm amplitude. Surface-electromyographic (EMG) activity of the Biceps Brachii, Triceps Brachii and Flexor Carpi Radialis were measured. EMG amplitude (EMGrms) and mean frequency (MEF) were computed to quantify muscle activity and fatigue levels. All muscles displayed significantly higher reduction in MEFs and a corresponding significant increase in EMGrms with the V than the Control, during fatiguing contractions (p < 0.05). Post vibration, all muscles showed higher levels of MEFs after recovery compared to the control. Our results show that near-maximal isometric fatiguing contractions superimposed on vibration stimulation lead to a higher rate of fatigue development compared to the isometric contraction alone in the upper limb muscles. Results also show higher manifestation of mechanical fatigue post treatment with vibration compared to the control. Vibration superimposed on isometric contraction not only seems to alter the neuromuscular function during fatiguing efforts by inducing higher neuromuscular load but also post vibration treatment.Peer reviewedFinal Published versio
Segregation by membrane rigidity in flowing binary suspensions of elastic capsules
Spatial segregation in the wall normal direction is investigated in
suspensions containing a binary mixture of Neo-Hookean capsules subjected to
pressure driven flow in a planar slit. The two components of the binary mixture
have unequal membrane rigidities. The problem is studied numerically using an
accelerated implementation of the boundary integral method. The effect of a
variety of parameters was investigated, including the capillary number,
rigidity ratio between the two species, volume fraction, confinement ratio, and
the number fraction of the more floppy particle in the mixture. It was
observed that in suspensions of pure species, the mean wall normal positions of
the stiff and the floppy particles are comparable. In mixtures, however, the
stiff particles were found to be increasingly displaced towards the walls with
increasing , while the floppy particles were found to increasingly
accumulate near the centerline with decreasing . The origins of this
segregation is traced to the effect of the number fraction on the
localization of the stiff and the floppy particles in the near wall region --
the probability of escape of a stiff particle from the near wall region to the
interior is greatly reduced with increasing , while the exact opposite
trend is observed for a floppy particle with decreasing . Simple model
studies on heterogeneous pair collisions involving a stiff and a floppy
particle mechanistically explain this observation. The key result in these
studies is that the stiff particle experiences much larger cross-stream
displacement in heterogeneous collisions than the floppy particle. A unified
mechanism incorporating the wall-induced migration of deformable particles and
the particle fluxes associated with heterogeneous and homogeneous pair
collisions is presented.Comment: 19 Pages, 16 Figure
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