28,180 research outputs found
Study reveals effect of aluminum on saturation moment of Fe-Ni alloys
Study of saturation magnetization, important in the investigation of the electronic structure of alloys, reveals the effect of aluminum on the saturation moments of iron-nickel alloys. The saturation magnetizations were extrapolated to the absolute zero of temperature for calculating average atomic moments
Near-barrier Fusion Induced by Stable Weakly Bound and Exotic Halo Light Nuclei
The effect of breakup is investigated for the medium weight
Li+Co system in the vicinity of the Coulomb barrier. The strong
coupling of breakup/transfer channels to fusion is discussed within a
comparison of predictions of the Continuum Discretized Coupled-Channels model
which is also applied to He+Co a reaction induced by the borromean
halo nucleus He.Comment: 6 pages, 3 figures. A talk given at the FUSION06: International
Conference on Reaction Mechanisms and Nuclear Structure at the Coulomb
barrier, March 19-23, 2006, San Servolo, Venezia, Ital
Biases in the polarization position angles in the NVSS point source catalogue
We have examined the statistics of the polarization position angles
determined for point sources in the NRAO-VLA sky survey (NVSS) and find that
there is a statistically significant bias toward angles which are multiples of
45 degrees. The formal probability that the polarization angles are drawn from
a uniform distribution is exponentially small. When the sample of those NVSS
sources with polarizations detected with a signal to noise 3 is split
either around the median polarized flux density or the median fractional
polarization, the effect appears to be stronger for the more highly polarized
sources. Regions containing strong sources and regions at low galactic
latitudes are not responsible for the non-uniform distribution of position
angles. We identify CLEAN bias as the probable cause of the dominant effect,
coupled with small multiplicative and additive offsets on each of the Stokes
parameters. Our findings have implications for the extraction of science, such
as information concerning galactic magnetic fields, from large scale
polarization surveys
Measuring non-extensitivity parameters in a turbulent Couette-Taylor flow
We investigate probability density functions of velocity differences at
different distances r measured in a Couette-Taylor flow for a range of Reynolds
numbers Re. There is good agreement with the predictions of a theoretical model
based on non-extensive statistical mechanics (where the entropies are
non-additive for independent subsystems). We extract the scale-dependent
non-extensitivity parameter q(r, Re) from the laboratory data.Comment: 8 pages, 5 figure
Regularity of a inverse problem for generic parabolic equations
The paper studies some inverse boundary value problem for simplest parabolic
equations such that the homogenuous Cauchy condition is ill posed at initial
time. Some regularity of the solution is established for a wide class of
boundary value inputs.Comment: 9 page
On prescribed change of profile for solutions of parabolic equations
Parabolic equations with homogeneous Dirichlet conditions on the boundary are
studied in a setting where the solutions are required to have a prescribed
change of the profile in fixed time, instead of a Cauchy condition. It is shown
that this problem is well-posed in L_2-setting. Existence and regularity
results are established, as well as an analog of the maximum principle
The neuropathology of kuru and variant Creutzfeldt–Jakob disease
A comparison of the pathological profiles of two spongiform encephalopathies with a similar presumptive route of infection was performed. Archival kuru and recent variant Creutzfeldt–Jakob disease (vCJD) cases reveal distinct lesional differences, particularly with respect to prion protein, suggesting that the strain of agent is important in determining the phenotype. Genotype analysis of the polymorphism on codon 129 reveals (in conjunction with updated information from more kuru cases) that all three genotypes (VV, MV and MM (where M is methionine and V is valine)) are detected in kuru with some preference for MM homozygosity. The presence of valine does not therefore appear to determine peripheral selection of PrPCJD. vCJD remains restricted to date to MM homozygosity on codon 129. It remains to be determined whether this genotype is dictating a shorter incubation period
Evidence for a high-z ISW signal from supervoids in the distribution of eBOSS quasars
The late-time integrated Sachs-Wolfe (ISW) imprint of super-structures is sourced by evolving large-scale
potentials due to a dominant dark energy component in the CDM model.
The aspect that makes the ISW effect distinctly interesting is the repeated
observation of stronger-than-expected imprints from supervoids at
. Here we analyze the un-probed key redshift range
where the ISW signal is expected to fade in CDM, due to a weakening
dark energy component, and eventually become consistent with zero in the matter
dominated epoch. On the contrary, alternative cosmological models, proposed to
explain the excess low- ISW signals, predicted a sign-change in the ISW
effect at due to the possible growth of large-scale potentials
that is absent in the standard model. To discriminate, we estimated the
high- CDM ISW signal using the Millennium XXL mock catalogue, and
compared it to our measurements from about 800 supervoids identified in the
eBOSS DR16 quasar catalogue. At , we found an excess ISW signal with
amplitude. The signal is then consistent with
the CDM expectation () at where the
standard and alternative models predict similar amplitudes. Most interestingly,
we also detected an opposite-sign ISW signal at that is in
tension with the CDM prediction. Taken at face value,
these moderately significant detections of ISW anomalies suggest an alternative
growth rate of structure in low-density environments at scales.Comment: 12 pages, 9 figures, submitted to MNRA
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