708 research outputs found
On mean convergence of Hermite–Fejér and Hermite interpolation for Erdős weights
AbstractWe investigate convergence of Hermite–Fejér and Hermite interpolation polynomials in Lp(0<p<∞) for Erdős weights
Necessary conditions for weighted mean convergence of Lagrange interpolation for exponential weights
AbstractGiven a continuous real-valued function f which vanishes outside a fixed finite interval, we establish necessary conditions for weighted mean convergence of Lagrange interpolation for a general class of even weights w which are of exponential decay on the real line or at the endpoints of (−1,1)
The sphingosine kinase activator K6PC-5 stimulates C2C12 myoblast differentiation.
Previously, K6PC-5, a synthetic derivative of ceramide, was demonstrated to activate sphingosine kinase (SK)-1 in keratinocytes. In this study its potential biological effect in mouse myoblasts was examined. The obtained results show that K6PC-5 promotes myogenic differentiation by enhancing myogenic marker expression, differentiation index and fusion index. Interestingly, its biological action was prevented by pharmacological inhibition of SK or S1P2 receptor, in full agreement with their recognized role in myoblast differentiation. This is the first evidence that pharmacological activation of SK accelerates myogenesis and suggests that this new therapeutic strategy could be possibly employed in skeletal muscle disorders where muscle regeneration is deficient
Single-filament Composite MgB2/SUS Ribbons by Powder-In-Tube Process
We report the successful fabrication of single-filament composite MgB2/SUS
ribbons, as an ultra-robust conductor type, employing the powder-in-tube (PIT)
process, by swaging and cold rolling only. The remarkable transport critical
current (Ic) of the non-sintered MgB2/SUS ribbon has observed, as an unexpected
result. Transport critical currents Ic ~ 316 A at T = 4.2 K and Ic ~ 82 A at T
= 20 K were observed at self-field, for the non-sintered composite MgB2/SUS
ribbon. In addition, the persistent current density Jp values, that were
estimated by Bean formula, were more than ~ 7  105 A/cm2 at T = 5 K,
and ~ 1.2  105 A/cm2 at T = 30 K, for the sintered composite MgB2/SUS
ribbon, at H = 0 G.Comment: 10 pages, 4 figure
Copper selenide film electrodes prepared by combined electrochemical/chemical bath depositions with high photo-electrochemical conversion efficiency and stability
Copper selenide (of the type Cu2-xSe) film electrodes, prepared by combined electrochemical (ECD)
followed by chemical bath deposition (CBD), may yield high photo-electrochemical (PEC) conversion
efficiency (~14.6%) with no further treatment. The new ECD/CBD-copper selenide film electrodes show
enhanced PEC characteristics and exhibit high stability under PEC conditions, compared to the ECD or the
CBD films deposited separately. The electrodes combine the advantages of both ECD-copper selenide
electrodes (in terms of good adherence to FTO surface and high surface uniformity) and CBD-copper
selenide electrodes (suitable film thickness). Effect of annealing temperature, on the ECD/CBD film
electrode composition and efficiency, is discussed.The results of this work are partly based on K. Murtada M.Sc.
Thesis, under direct supervision of H.S. Hilal. Other experimental
measurements and calculations, including dark current experiments,
film thickness measurement, electrical conductivity, SEM
analysis, XRD &AFM analysis revisions were performed by A. Zyoud
after the thesis completion. Additional film electrode stability experiments
under PEC conditions, were also performed by A. Zyoud
after the Thesis completion. SEM micrographs and EDX spectra
were measured by T.W. Kim and H-J.C. at the KIER, Korea. The XRD
patterns were measured by D-H. Park and H. Kwon at PUK. M.H.S.
Helal and H. Bsharat contributed with literature search, discussions
and modeling. M. Faroun measured AFM micrographs at Al-Quds
University. H.S. Hilal acknowledges financial support from ANU,
Islamic Development Bank, Al-Maqdisi Project and Union of Arab
Universities. T.W. Kim and H-J. Choi acknowledge financial support
from the framework of the Research and Development Program of
the Korea Institute of Energy Research (B6-2523)
Itinerant ferromagnetism in half-metallic CoS_2
We have investigated electronic and magnetic properties of the pyrite-type
CoS_2 using the linearized muffin-tin orbital (LMTO) band method. We have
obtained the ferromagnetic ground state with nearly half-metallic nature. The
half-metallic stability is studied by using the fixed spin moment method. The
non-negligible orbital magnetic moment of Co 3d electrons is obtained as in the local spin density approximation (LSDA). The calculated
ratio of the orbital to spin angular momenta / = 0.15 is
consistent with experiment. The effect of the Coulomb correlation between Co 3d
electrons is also explored with the LSDA + U method. The Coulomb correlation at
Co sites is not so large, eV, and so CoS_2 is possibly
categorized as an itinerant ferromagnet. It is found that the observed
electronic and magnetic behaviors of CoS_2 can be described better by the LSDA
than by the LSDA + U.Comment: 4 pages, 3 postscript figure
Neutron beam test of CsI crystal for dark matter search
We have studied the response of Tl-doped and Na-doped CsI crystals to nuclear
recoils and 's below 10 keV. The response of CsI crystals to nuclear
recoil was studied with mono-energetic neutrons produced by the
H(p,n)He reaction. This was compared to the response to Compton
electrons scattered by 662 keV -ray. Pulse shape discrimination between
the response to these 's and nuclear recoils was studied, and quality
factors were estimated. The quenching factors for nuclear recoils were derived
for both CsI(Na) and CsI(Tl) crystals.Comment: 21pages, 14figures, submitted to NIM
Modelling of strain effects in manganite films
Thickness dependence and strain effects in films of
perovskites are analyzed in the colossal magnetoresistance regime. The
calculations are based on a generalization of a variational approach previously
proposed for the study of manganite bulk. It is found that a reduction in the
thickness of the film causes a decrease of critical temperature and
magnetization, and an increase of resistivity at low temperatures. The strain
is introduced through the modifications of in-plane and out-of-plane electron
hopping amplitudes due to substrate-induced distortions of the film unit cell.
The strain effects on the transition temperature and transport properties are
in good agreement with experimental data only if the dependence of the hopping
matrix elements on the bond angle is properly taken into account.
Finally variations of the electron-phonon coupling linked to the presence of
strain turn out important in influencing the balance of coexisting phases in
the filmComment: 7 figures. To be published on Physical Review
Novel universality class of absorbing transitions with continuously varying critical exponents
The well-established universality classes of absorbing critical phenomena are
directed percolation (DP) and directed Ising (DI) classes. Recently, the pair
contact process with diffusion (PCPD) has been investigated extensively and
claimed to exhibit a new type of critical phenomena distinct from both DP and
DI classes. Noticing that the PCPD possesses a long-term memory effect, we
introduce a generalized version of the PCPD (GPCPD) with a parameter
controlling the memory effect. The GPCPD connects the DP fixed point to the
PCPD point continuously. Monte Carlo simulations show that the GPCPD displays
novel type critical phenomena which are characterized by continuously varying
critical exponents. The same critical behaviors are also observed in models
where two species of particles are coupled cyclically. We suggest that the
long-term memory may serve as a marginal perturbation to the ordinary DP fixed
point.Comment: 13 pages + 10 figures (Full paper version
Search for sterile neutrino oscillation using RENO and NEOS data
We present a reactor model independent search for sterile neutrino
oscillation using 2\,509\,days of RENO near detector data and 180 days of NEOS
data. The reactor related systematic uncertainties are significantly suppressed
as both detectors are located at the same reactor complex of Hanbit Nuclear
Power Plant. The search is performed by electron
antineutrino\,() disappearance between six reactors and two
detectors with baselines of 294\,m\,(RENO) and 24\,m\,(NEOS). A spectral
comparison of the NEOS prompt-energy spectrum with a no-oscillation prediction
from the RENO measurement can explore reactor oscillations
to sterile neutrino. Based on the comparison, we obtain a 95\% C.L. excluded
region of \,eV. We also obtain a 68\% C.L. allowed
region with the best fit of \,eV and
=0.080.03 with a p-value of 8.2\%. Comparisons of
obtained reactor antineutrino spectra at reactor sources are made among RENO,
NEOS, and Daya Bay to find a possible spectral variation.Comment: 6 pages, 5 figures: This manuscript has been significantly revised by
the joint reanalysis by RENO and NEOS Collaborations. (In the previous
edition, the RENO collaboration used publicly available NEOS data to evaluate
the expected neutrino spectrum at NEOS.
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