1,710 research outputs found
Operation of hydrodynamic journal bearings in sodium at temperatures to 800 deg F and speeds to 12000 rpm
Operation of hydrodynamic journal bearings in liquid sodium at high temperatures and high speed
A new sdO+dM binary with extreme eclipses and reflection effect
We report the discovery of a new totally-eclipsing binary (RA=06:40:29.11;
Dec=+38:56:52.2; J=2000.0; Rmax=17.2 mag) with an sdO primary and a strongly
irradiated red dwarf companion. It has an orbital period of
Porb=0.187284394(11) d and an optical eclipse depth in excess of 5 magnitudes.
We obtained two low-resolution classification spectra with GTC/OSIRIS and ten
medium-resolution spectra with WHT/ISIS to constrain the properties of the
binary members. The spectra are dominated by H Balmer and He II absorption
lines from the sdO star, and phase-dependent emission lines from the irradiated
companion. A combined spectroscopic and light curve analysis implies a hot
subdwarf temperature of Teff(spec) = 55 000 +/- 3000K, surface gravity of log
g(phot) = 6.2 +/- 0.04 (cgs) and a He abundance of log(nHe/nH) = -2.24 +/-
0.40. The hot sdO star irradiates the red-dwarf companion, heating its
substellar point to about 22 500K. Surface parameters for the companion are
difficult to constrain from the currently available data: the most remarkable
features are the strong H Balmer and C II-III lines in emission. Radial
velocity estimates are consistent with the sdO+dM classification. The
photometric data do not show any indication of sdO pulsations with amplitudes
greater than 7mmag, and Halpha-filter images do not provide evidence of the
presence of a planetary nebula associated with the sdO star.Comment: 13 pages, 5 figures; accepted for publication in Ap
A Portuguese patient homozygous for the -25G>A mutation of the HAMP promoter shows evidence of steady-state transcription but fails to up-regulate hepcidin levels by iron.
Blood. 2005 Oct 15;106(8):2922-3.
A Portuguese patient homozygous for the -25G>A mutation of the HAMP promoter shows evidence of steady-state transcription but fails to up-regulate hepcidin levels by iron.
Porto G, Roetto A, Daraio F, Pinto JP, Almeida S, Bacelar C, Nemeth E, Ganz T, Camaschella C.
PMID: 16204153 [PubMed - indexed for MEDLINE]Free Article
Publication Types, MeSH Terms, SubstancesPublication Types:
Letter
Research Support, Non-U.S. Gov't
MeSH Terms:
Antimicrobial Cationic Peptides/genetics*
Antimicrobial Cationic Peptides/urine
Glycine/genetics*
Hemochromatosis/genetics
Homozygote*
Humans
Iron/pharmacology*
Mutation/genetics
Portugal
Promoter Regions, Genetic/genetics*
Transcription, Genetic/genetics*
Up-Regulation/drug effects*
Substances:
Antimicrobial Cationic Peptides
hepcidin
Glycine
Iron
LinkOut - more resourcesFull Text Sources:
HighWire Press
EBSCO
Other Literature Sources:
COS Scholar Universe
Medical:
Genetics Home Reference - HAMP Gene - Genetics Home Reference
Molecular Biology Databases:
IRON - HSDB
GLYCINE - HSD
Orbital Magnetism and Current Distribution of Two-Dimensional Electrons under Confining Potential
The spatial distribution of electric current under magnetic field and the
resultant orbital magnetism have been studied for two-dimensional electrons
under a harmonic confining potential V(\vecvar{r})=m \omega_0^2 r^2/2 in
various regimes of temperature and magnetic field, and the microscopic
conditions for the validity of Landau diamagnetism are clarified. Under a weak
magnetic field (\omega_c\lsim\omega_0, \omega_c being a cyclotron frequency)
and at low temperature (T\lsim\hbar\omega_0), where the orbital magnetic
moment fluctuates as a function of the field, the currents are irregularly
distributed paramagnetically or diamagnetically inside the bulk region. As the
temperature is raised under such a weak field, however, the currents in the
bulk region are immediately reduced and finally there only remains the
diamagnetic current flowing along the edge. At the same time, the usual Landau
diamagnetism results for the total magnetic moment. The origin of this dramatic
temperature dependence is seen to be in the multiple reflection of electron
waves by the boundary confining potential, which becomes important once the
coherence length of electrons gets longer than the system length. Under a
stronger field (\omega_c\gsim\omega_0), on the other hand, the currents in
the bulk region cause de Haas-van Alphen effect at low temperature as
T\lsim\hbar\omega_c. As the temperature gets higher (T\gsim\hbar\omega_c)
under such a strong field, the bulk currents are reduced and the Landau
diamagnetism by the edge current is recovered.Comment: 15 pages, 11 figure
Spatial distribution of low-energy plasma around 2 comet 67P/CG from Rosetta measurements
International audienceWe use measurements from the Rosetta plasma consortium (RPC) Langmuir probe (LAP) and mutual impedance probe (MIP) to study the spatial distribution of low-energy plasma in the near-nucleus coma of comet 67P/Churyumov-Gerasimenko. The spatial distribution is highly structured with the highest density in the summer hemisphere and above the region connecting the two main lobes of the comet, i.e. the neck region. There is a clear correlation with the neutral density and the plasma to neutral density ratio is found to be ∼1-2·10 −6 , at a cometocentric distance of 10 km and at 3.1 AU from the sun. A clear 6.2 h modulation of the plasma is seen as the neck is exposed twice per rotation. The electron density of the collisonless plasma within 260 km from the nucleus falls of with radial distance as ∼1/r. The spatial structure indicates that local ionization of neutral gas is the dominant source of low-energy plasma around the comet
Oxpentifylline versus placebo in the treatment of erythropoietin-resistant anaemia: a randomized controlled trial
Background: The main hypothesis of this study is that Oxpentifylline administration will effectively treat erythropoietin-or darbepoietin-resistant anaemia in chronic kidney disease patients
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