2,072 research outputs found
Condition for the Existence of Complex Modes in a Trapped Bose--Einstein Condensate with a Highly Quantized Vortex
We consider a trapped Bose--Einstein condensate (BEC) with a highly quantized
vortex. For the BEC with a doubly, triply or quadruply quantized vortex, the
numerical calculations have shown that the Bogoliubov--de Gennes equations,
which describe the fluctuation of the condensate, have complex eigenvalues. In
this paper, we obtain the analytic expression of the condition for the
existence of complex modes, using the method developed by Rossignoli and
Kowalski [R. Rossignoli and A. M. Kowalski, Phys. Rev. A 72, 032101 (2005)] for
the small coupling constant. To derive it, we make the two-mode approximation.
With the derived analytic formula, we can identify the quantum number of the
complex modes for each winding number of the vortex. Our result is consistent
with those obtained by the numerical calculation in the case that the winding
number is two, three or four. We prove that the complex modes always exist when
the condensate has a highly quantized vortex
Condition for emergence of complex eigenvalues in the Bogoliubov-de Gennes equations
The condition for the appearance of dynamical instability of the
Bose-condensed system, characterized by the emergence of complex eigenvalues in
the Bogoliubov-de Gennes equations, is studied analytically. We perturbatively
expand both the Gross-Pitaevskii and Bogoliubov-de Gennes equations with
respect to the coupling constant. It is concluded that the degeneracy between a
positive-norm eigenmode and a negative-norm one is essential for the emergence
of complex modes. Based on the conclusion, we justify the two-mode
approximation applied in our previous work [E. Fukuyama \textit{et al}., Phys.
Rev. A {\bf 76}, 043608 (2007)], in which we analytically studied the condition
for the existence of complex modes when the condensate has a highly quantized
vortex.Comment: 7page
Effect of chemical treatments on physico-chemical properties of fibres from banana fruit and bunch stems
Fibres have been extracted from fruit and bunch stems of banana plant by water retting and evaluated in terms of their performance characteristics. Banana bunch stem fibres have been found to be superior in terms of fineness, initial modulus and breaking strength, whereas elongation ratio shows an inverse trend. Thus, they have been further treated by bleaching and alkalization. Among the treated fibres, the bleached fibres show the highest initial modulus, breaking tenacity, and the lowest elongation. Alkalization results in increased breaking elongation and decreased initial modulus, whiteness and water absorption. The bunch stem fibres present higher water absorptive capacity and lower whiteness compared to that of fruit stem fibres. The characteristics of these unconventional fibres have been found to be comparable to natural fibres traditionally used in textiles. The ranges for properties of the studied banana fruit and bunch stem fibres in general can be given as: linear density 12.71-20.38 tex, initial moduli 168 -326 cN/tex, breaking tenacity 9.89-13.3 cN/tex, breaking elongation 4.42-16.4%, and moisture content 11.6-15.8%
Application of Market Models to Network Equilibrium Problems
We present a general two-side market model with divisible commodities and
price functions of participants. A general existence result on unbounded sets
is obtained from its variational inequality re-formulation. We describe an
extension of the network flow equilibrium problem with elastic demands and a
new equilibrium type model for resource allocation problems in wireless
communication networks, which appear to be particular cases of the general
market model. This enables us to obtain new existence results for these models
as some adjustments of that for the market model. Under certain additional
conditions the general market model can be reduced to a decomposable
optimization problem where the goal function is the sum of two functions and
one of them is convex separable, whereas the feasible set is the corresponding
Cartesian product. We discuss some versions of the partial linearization
method, which can be applied to these network equilibrium problems.Comment: 18 pages, 3 table
Bi-allelic JAM2 Variants Lead to Early-Onset Recessive Primary Familial Brain Calcification.
Primary familial brain calcification (PFBC) is a rare neurodegenerative disorder characterized by a combination of neurological, psychiatric, and cognitive decline associated with calcium deposition on brain imaging. To date, mutations in five genes have been linked to PFBC. However, more than 50% of individuals affected by PFBC have no molecular diagnosis. We report four unrelated families presenting with initial learning difficulties and seizures and later psychiatric symptoms, cerebellar ataxia, extrapyramidal signs, and extensive calcifications on brain imaging. Through a combination of homozygosity mapping and exome sequencing, we mapped this phenotype to chromosome 21q21.3 and identified bi-allelic variants in JAM2. JAM2 encodes for the junctional-adhesion-molecule-2, a key tight-junction protein in blood-brain-barrier permeability. We show that JAM2 variants lead to reduction of JAM2 mRNA expression and absence of JAM2 protein in patient's fibroblasts, consistent with a loss-of-function mechanism. We show that the human phenotype is replicated in the jam2 complete knockout mouse (jam2 KO). Furthermore, neuropathology of jam2 KO mouse showed prominent vacuolation in the cerebral cortex, thalamus, and cerebellum and particularly widespread vacuolation in the midbrain with reactive astrogliosis and neuronal density reduction. The regions of the human brain affected on neuroimaging are similar to the affected brain areas in the myorg PFBC null mouse. Along with JAM3 and OCLN, JAM2 is the third tight-junction gene in which bi-allelic variants are associated with brain calcification, suggesting that defective cell-to-cell adhesion and dysfunction of the movement of solutes through the paracellular spaces in the neurovascular unit is a key mechanism in CNS calcification
Tracking Performance of the Scintillating Fiber Detector in the K2K Experiment
The K2K long-baseline neutrino oscillation experiment uses a Scintillating
Fiber Detector (SciFi) to reconstruct charged particles produced in neutrino
interactions in the near detector. We describe the track reconstruction
algorithm and the performance of the SciFi after three years of operation.Comment: 24pages,18 figures, and 1 table. Preprint submitted to NI
Colorectal cancer linkage on chromosomes 4q21, 8q13, 12q24, and 15q22
A substantial proportion of familial colorectal cancer (CRC) is not a consequence of known susceptibility loci, such as mismatch repair (MMR) genes, supporting the existence of additional loci. To identify novel CRC loci, we conducted a genome-wide linkage scan in 356 white families with no evidence of defective MMR (i.e., no loss of tumor expression of MMR proteins, no microsatellite instability (MSI)-high tumors, or no evidence of linkage to MMR genes). Families were ascertained via the Colon Cancer Family Registry multi-site NCI-supported consortium (Colon CFR), the City of Hope Comprehensive Cancer Center, and Memorial University of Newfoundland. A total of 1,612 individuals (average 5.0 per family including 2.2 affected) were genotyped using genome-wide single nucleotide polymorphism linkage arrays; parametric and non-parametric linkage analysis used MERLIN in a priori-defined family groups. Five lod scores greater than 3.0 were observed assuming heterogeneity. The greatest were among families with mean age of diagnosis less than 50 years at 4q21.1 (dominant HLOD = 4.51, α = 0.84, 145.40 cM, rs10518142) and among all families at 12q24.32 (dominant HLOD = 3.60, α = 0.48, 285.15 cM, rs952093). Among families with four or more affected individuals and among clinic-based families, a common peak was observed at 15q22.31 (101.40 cM, rs1477798; dominant HLOD = 3.07, α = 0.29; dominant HLOD = 3.03, α = 0.32, respectively). Analysis of families with only two affected individuals yielded a peak at 8q13.2 (recessive HLOD = 3.02, α = 0.51, 132.52 cM, rs1319036). These previously unreported linkage peaks demonstrate the continued utility of family-based data in complex traits and suggest that new CRC risk alleles remain to be elucidated. © 2012 Cicek et al
Measurement of the diffractive structure function in deep inelastic scattering at HERA
This paper presents an analysis of the inclusive properties of diffractive
deep inelastic scattering events produced in interactions at HERA. The
events are characterised by a rapidity gap between the outgoing proton system
and the remaining hadronic system. Inclusive distributions are presented and
compared with Monte Carlo models for diffractive processes. The data are
consistent with models where the pomeron structure function has a hard and a
soft contribution. The diffractive structure function is measured as a function
of \xpom, the momentum fraction lost by the proton, of , the momentum
fraction of the struck quark with respect to \xpom, and of . The \xpom
dependence is consistent with the form \xpoma where
in all bins of and
. In the measured range, the diffractive structure function
approximately scales with at fixed . In an Ingelman-Schlein type
model, where commonly used pomeron flux factor normalisations are assumed, it
is found that the quarks within the pomeron do not saturate the momentum sum
rule.Comment: 36 pages, latex, 11 figures appended as uuencoded fil
Evidence for oscillation of atmospheric neutrinos
We present an analysis of atmospheric neutrino data from a 33.0 kiloton-year
(535-day) exposure of the Super-Kamiokande detector. The data exhibit a zenith
angle dependent deficit of muon neutrinos which is inconsistent with
expectations based on calculations of the atmospheric neutrino flux.
Experimental biases and uncertainties in the prediction of neutrino fluxes and
cross sections are unable to explain our observation. The data are consistent,
however, with two-flavor nu_mu nu_tau oscillations with sin^2(2theta)>0.82
and 5x10^-4 < delta m^2 < 6x10^-3 eV^2 at 90% confidence level.Comment: 9 pages (two-column) with 4 figures. Small corrections to Eqn.4 and
Fig.3. Final version to appear in PR
Search for Supernova Relic Neutrinos at Super-Kamiokande
A search for the relic neutrinos from all past core-collapse supernovae was
conducted using 1496 days of data from the Super-Kamiokande detector. This
analysis looked for electron-type anti-neutrinos that had produced a positron
with an energy greater than 18 MeV. In the absence of a signal, 90% C.L. upper
limits on the total flux were set for several theoretical models; these limits
ranged from 20 to 130 nu_e bar cm^-2 s^-1. Additionally, an upper bound of 1.2
nu_e bar cm^-2 s^-1 was set for the supernova relic neutrino flux in the energy
region E_nu > 19.3 MeV.Comment: 4 pages, 2 figures. Submitted to Physical Review Letters. New version
includes corrections to Figure 1. Also, text has been shortened to conform
with the space limitations of PR
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