1,678 research outputs found
Origin of the giant magnetic moments of Fe impurities on and in Cs films
To explore the origin of the observed giant magnetic moments ()
of Fe impurities on the surface and in the bulk of Cs films, we have performed
the relativistic LSDA + U calculations using the linearized muffin-tin orbital
(LMTO) band method. We have found that Fe impurities in Cs behave differently
from those in noble metals or in Pd. Whereas the induced spin polarization of
Cs atoms is negligible, the Fe ion itself is found to be the source of the
giant magnetic moment. The 3d electrons of Fe in Cs are localized as the 4f
electrons in rare-earth ions so that the orbital magnetic moment becomes as
large as the spin magnetic moment. The calculated total magnetic moment of , which comes mainly from Fe ion, is close to the experimentally
observed value.Comment: 4 pages including 3 figures and 1 table. Submitted to PR
Clinical Effectiveness, Access to, and Satisfaction with Care Using a Telehomecare Substitution Intervention: A Randomized Controlled Trial
Background.
Hospitalization accounts for 70% of heart
failure (HF) costs; readmission rates at 30 days
are 24% and rise to 50% by 90 days.
Agencies anticipate that telehomecare will
provide the close monitoring necessary to
prevent HF readmissions. Methods and
Results. Randomized controlled trial to
compare a telehomecare intervention for patients
55 and older following hospital discharge for HF
to usual skilled home care. Primary endpoints
were 30- and 60-day all-cause and HF readmission,
hospital days, and time to readmission or death.
Secondary outcomes were access to care,
emergency department (ED) use, and satisfaction
with care. All-cause readmissions at 30 days
(16% versus 19%) and over six months
(46% versus 52%) were lower in the
telehomecare group but were not statistically
significant. Access to care and satisfaction
were significantly higher for the telehomecare
patients, including the number of in-person
visits and days in home care.
Conclusions. Patient acceptance
of the technology and current home care policies
and processes of care were barriers to gaining
clinical effectiveness and
efficiency
An Automated Method for the Detection and Extraction of HI Self-Absorption in High-Resolution 21cm Line Surveys
We describe algorithms that detect 21cm line HI self-absorption (HISA) in
large data sets and extract it for analysis. Our search method identifies HISA
as spatially and spectrally confined dark HI features that appear as negative
residuals after removing larger-scale emission components with a modified CLEAN
algorithm. Adjacent HISA volume-pixels (voxels) are grouped into features in
(l,b,v) space, and the HI brightness of voxels outside the 3-D feature
boundaries is smoothly interpolated to estimate the absorption amplitude and
the unabsorbed HI emission brightness. The reliability and completeness of our
HISA detection scheme have been tested extensively with model data. We detect
most features over a wide range of sizes, linewidths, amplitudes, and
background levels, with poor detection only where the absorption brightness
temperature amplitude is weak, the absorption scale approaches that of the
correlated noise, or the background level is too faint for HISA to be
distinguished reliably from emission gaps. False detection rates are very low
in all parts of the parameter space except at sizes and amplitudes approaching
those of noise fluctuations. Absorption measurement biases introduced by the
method are generally small and appear to arise from cases of incomplete HISA
detection. This paper is the third in a series examining HISA at high angular
resolution. A companion paper (Paper II) uses our HISA search and extraction
method to investigate the cold atomic gas distribution in the Canadian Galactic
Plane Survey.Comment: 39 pages, including 14 figure pages; to appear in June 10 ApJ, volume
626; figure quality significantly reduced for astro-ph; for full resolution,
please see http://www.ras.ucalgary.ca/~gibson/hisa/cgps1_survey
First Experimental Characterization of Microwave Emission from Cosmic Ray Air Showers
We report the first direct measurement of the overall characteristics of
microwave radio emission from extensive air showers. Using a trigger provided
by the KASCADE-Grande air shower array, the signals of the microwave antennas
of the CROME (Cosmic-Ray Observation via Microwave Emission) experiment have
been read out and searched for signatures of radio emission by high-energy air
showers in the GHz frequency range. Microwave signals have been detected for
more than 30 showers with energies above 3*10^16 eV. The observations presented
in this Letter are consistent with a mainly forward-directed and polarised
emission process in the GHz frequency range. The measurements show that
microwave radiation offers a new means of studying air showers at energies
above 10^17 eV.Comment: Accepted for publication in PR
HI Narrow Line Absorption in Dark Clouds
We have used the Arecibo telescope to carry out an survey of 31 dark clouds
in the Taurus/Perseus region for narrow absorption features in HI (
21cm) and OH (1667 and 1665 MHz) emission. We detected HI narrow
self--absorption (HINSA) in 77% of the clouds that we observed. HINSA and OH
emission, observed simultaneously are remarkably well correlated. Spectrally,
they have the same nonthermal line width and the same line centroid velocity.
Spatially, they both peak at the optically--selected central position of each
cloud, and both fall off toward the cloud edges. Sources with clear HINSA
feature have also been observed in transitions of CO, \13co, \c18o, and CI.
HINSA exhibits better correlation with molecular tracers than with CI.
The line width of the absorption feature, together with analyses of the
relevant radiative transfer provide upper limits to the kinetic temperature of
the gas producing the HINSA. Some sources must have a temperature close to or
lower than 10 K. The correlation of column densities and line widths of HINSA
with those characteristics of molecular tracers suggest that a significant
fraction of the atomic hydrogen is located in the cold, well--shielded portions
of molecular clouds, and is mixed with the molecular gas.
The average number density ratio [HI]/[\h2] is . The
inferred HI density appears consistent with but is slightly higher than the
value expected in steady state equilibrium between formation of HI via cosmic
ray destruction of H and destruction via formation of H on grain
surfaces. The distribution and abundance of atomic hydrogen in molecular clouds
is a critical test of dark cloud chemistry and structure, including the issues
of grain surface reaction rates, PDRs, circulation, and turbulent diffusion.Comment: 40 pages, 10 figures, accepted by Ap
Perinatal death by bile acid levels in intrahepatic cholestasis of pregnancy: a systematic review
Background: Intrahepatic cholestasis of pregnancy (ICP) is characterized by the elevation of total bile acids (TBAs). The primary concern in women with ICP is the increased risk of stillbirth. ICP is generally considered as “mild” when TBA levels range from 10 to 39 µmol/L and “severe” with levels greater than 40 µmol/L, although levels of TBA ≥100 µmol/L have been also considered as a further threshold of severity. Objective: To quantify the association between different severities of ICP (TBA 10–39, 40–99, and ≥100 µmol/L) and perinatal death. Data sources: Medline, Embase, Scopus, Web of Sciences, and ClinicalTrial.gov were searched from the inception of each database to February 2019. Methods of study selection: Randomized, cohort, case-control, or case series studies reporting maternal and perinatal outcomes on women with ICP by the three prespecified TBA levels (10–39, 40–99, and ≥100 µmol/L) were included. We excluded multiple gestations and trials which included an intervention. The analysis was performed with Pearson chi-square and Fisher’s exact test as appropriate. Continuous outcomes were compared using metaregression with inverse variance weighting using reported sample sizes and standard deviations. Pairwise comparisons used a Bonferroni correction to control for multiple testing. Tabulation, integration, and results: Six articles including 1280 singleton pregnancies affected by ICP were included in the systematic review. Out of the 1280 singleton pregnancies affected by ICP included, 118 had ICP with TBA ≥100 µmol/L. Perinatal death was more common in women with TBA ≥100 µmol/L (0.4% for TBA 10-39 μmol/L versus 0.3% for TBA 40-99 μmol/L versus 6.8% for TBA ≥ 100 μmol/L, p <.0001). Of the 8 perinatal deaths in the TBA ≥100 µmol/L group, 3 occurred ≥34 weeks. TBA ≥100 µmol/L increased the risk of spontaneous preterm birth (PTB) (5.4% versus 8.6% versus 18.2% respectively, p <.0001) and iatrogenic PTB (10.8% versus 21.6% versus 35.8% respectively, p<.0001) as well as meconium-stained amniotic fluid (9.0% versus 18.4% versus 31.6% respectively, p <.0001). Conclusions: Maternal TBA ≥100 µmol/L is associated with a 6.8% incidence of perinatal death, most of which (5.9% overall) are stillbirths, while TBA <100 µmol/L are associated with an incidence of perinatal death of 0.3%. It may be reasonable to consider late preterm delivery (at about 35–36 weeks) in women with TBA ≥100 µmol/L
Solar cell process development in the european integrated project crystalclear
CrystalClear is a large integrated project funded by the European Commission that aims to drastically reduce the cost of crystalline Si PV modules, down to 1 Euro/Wp. Among the different subprojects, the one dealing with the development of advanced solar cells is relatively large (with 11 partners out of the 15 Crystal Clear partners taking part) and has a crucial role. The goal of the subproject is to develop cell design concepts and manufacturing processes that would enable a reduction in the order of 40% of the cell processing costs per Wp. In this paper, we give an overview of all the development work that has taken place in the CrystalClear solar cells subproject so far. World class results have been achieved, particularly on high efficiency cells on Si ribbons, and on industrial-type solar cells on very thin (120 (j.m thick) substrates
Simultaneous multi-frequency observation of the unknown redshift blazar PG 1553+113 in March-April 2008
The blazar PG 1553+113 is a well known TeV gamma-ray emitter. In this paper,
we determine its spectral energy distribution using simultaneous
multi-frequency data in order to study its emission processes. An extensive
campaign was carried out between March and April 2008, where optical, X-ray,
high-energy (HE) gamma-ray, and very-high-energy (VHE) gamma-ray data were
obtained with the KVA, Abastumani, REM, RossiXTE/ASM, AGILE and MAGIC
telescopes, respectively. This is the first simultaneous broad-band (i.e.,
HE+VHE) gamma-ray observation, though AGILE did not detect the source. We
combine data to derive source's spectral energy distribution and interpret its
double peaked shape within the framework of a synchrotron self compton modelComment: 5 pages, 2 figures, publishe
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