19,930 research outputs found
Spin-dependent phenomena and device concepts explored in (Ga,Mn)As
Over the past two decades, the research of (Ga,Mn)As has led to a deeper
understanding of relativistic spin-dependent phenomena in magnetic systems. It
has also led to discoveries of new effects and demonstrations of unprecedented
functionalities of experimental spintronic devices with general applicability
to a wide range of materials. In this article we review the basic material
properties that make (Ga,Mn)As a favorable test-bed system for spintronics
research and discuss contributions of (Ga,Mn)As studies in the general context
of the spin-dependent phenomena and device concepts. Special focus is on the
spin-orbit coupling induced effects and the reviewed topics include the
interaction of spin with electrical current, light, and heat.Comment: 47 pages, 41 figure
A Novel Sequence-Based Antigenic Distance Measure for H1N1, with Application to Vaccine Effectiveness and the Selection of Vaccine Strains
H1N1 influenza causes substantial seasonal illness and was the subtype of the
2009 influenza pandemic. Precise measures of antigenic distance between the
vaccine and circulating virus strains help researchers design influenza
vaccines with high vaccine effectiveness. We here introduce a sequence-based
method to predict vaccine effectiveness in humans. Historical epidemiological
data show that this sequence-based method is as predictive of vaccine
effectiveness as hemagglutination inhibition (HI) assay data from ferret animal
model studies. Interestingly, the expected vaccine effectiveness is greater
against H1N1 than H3N2, suggesting a stronger immune response against H1N1 than
H3N2. The evolution rate of hemagglutinin in H1N1 is also shown to be greater
than that in H3N2, presumably due to greater immune selection pressure.Comment: 26 pages, 7 figures, 2 tables, supplemen
Embedded disks in Fornax dwarf ellipticals
We present photometric and kinematic evidence for the presence of stellar
disks, seen practically edge-on, in two Fornax dwarf galaxies, FCC204 (dS0(6))
and FCC288 (dS0(7)). This is the first time such structures have been
identified in Fornax dwarfs. FCC2088 has only a small bulge and a bright
flaring and slightly warped disk that can be traced out to 23" from the center
(2.05 kpc for H_0=75 km/s/Mpc). FCC204's disk can be traced out to 20" (1.78
kpc). This galaxy possesses a large bulge. These results can be compared to the
findings of Jerjen et al. (2000) and Barazza et al. (2002) who discovered
nucleated dEs with spiral and bar features in the Virgo Cluster.Comment: 8 pages, 8 figures, accepted for publication in A&
New high-pressure phase and equation of state of Ce2Zr2O8
In this paper we report a new high-pressure rhombohedral phase of Ce2Zr2O8
observed from high-pressure angle-dispersive x-ray diffraction and Raman
spectroscopy studies up to nearly 12 GPa. The ambient-pressure cubic phase of
Ce2Zr2O8 transforms to a rhombohedral structure beyond 5 GPa with a feeble
distortion in the lattice. Pressure evolution of unit-cell volume showed a
change in compressibility above 5 GPa. The unit-cell parameters of the
high-pressure rhombohedral phase at 12.1 GPa are ah = 14.6791(3) {\AA}, ch =
17.9421(5) {\AA}, V = 3348.1(1) {\AA}3. The structure relation between the
parent cubic (P2_13) and rhombohedral (P3_2) phases were obtained by
group-subgroup relations. All the Raman modes of the cubic phase showed linear
evolution with pressure with the hardest one at 197 cm-1. Some Raman modes of
the high-pressure phase have a non-linear evolution with pressure and softening
of one low-frequency mode with pressure is found. The compressibility, equation
of state, and pressure coefficients of Raman modes of Ce2Zr2O8 are also
reported.Comment: 33 pages, 8 figures, 6 table
The Origin of N III λ990 and C III λ977 Emission in AGN Narrow-Line Region Gas
We discuss implications of Hopkins Ultraviolet Telescope (HUT) detections of C III λ977 and N III λ990 emission from the narrow-line region of the Seyfert 2 galaxy NGC 1068. In their discovery paper Kriss et al. showed that the unexpectedly great strength of these lines implies that the emitting gas must be shock-heated if the lines are collisionally excited. Here we investigate other processes which excite these lines in photoionization equilibrium. Recombination, mainly dielectronic, and continuum fluorescence are strong contributors to the line. The resulting intensities are sensitive to the velocity field of the emitting gas and require that the turbulence be of the same order of magnitude as the observed line width. We propose optical observations that will decide whether the gas is collisionally or radiatively heated
Boundary crossing Random Walks, clinical trials and multinomial sequential estimation
A sufficient condition for the uniqueness of multinomial sequential unbiased
estimators is provided generalizing a classical result for binomial samples.
Unbiased estimators are applied to infer the parameters of multidimensional or
multinomial Random Walks which are observed until they reach a boundary. An
application to clinical trials is presented
Aerobic Photobiocatalysis Enabled by Combining Core-Shell Nanophotoreactors and Native Enzymes
Acute post-disaster medical needs of patients with diabetes: emergency department use in New York City by diabetic adults after Hurricane Sandy.
OBJECTIVE: To evaluate the acute impact of disasters on diabetic patients, we performed a geospatial analysis of emergency department (ED) use by New York City diabetic adults in the week after Hurricane Sandy.
RESEARCH DESIGN AND METHODS: Using an all-payer claims database, we retrospectively analyzed the demographics, insurance status, and medical comorbidities of post-disaster ED patients with diabetes who lived in the most geographically vulnerable areas. We compared the patterns of ED use among diabetic adults in the first week after Hurricane Sandy\u27s landfall to utilization before the disaster in 2012.
RESULTS: In the highest level evacuation zone in New York City, postdisaster increases in ED visits for a primary or secondary diagnosis of diabetes were attributable to a significantly higher proportion of Medicare patients. Emergency visits for a primary diagnosis of diabetes had an increased frequency of certain comorbidities, including hypertension, recent procedure, and chronic skin ulcers. Patients with a history of diabetes visited EDs in increased numbers after Hurricane Sandy for a primary diagnosis of myocardial infarction, prescription refills, drug dependence, dialysis, among other conditions.
CONCLUSIONS: We found that diabetic adults aged 65 years and older are especially at risk for requiring postdisaster emergency care compared to other vulnerable populations. Our findings also suggest that there is a need to support diabetic adults particularly in the week after a disaster by ensuring access to medications, aftercare for patients who had a recent procedure, and optimize their cardiovascular health to reduce the risk of heart attacks
On a model mechanism for the spatial patterning of teeth primordia in the Alligator
We propose a model mechanism for the initiation and spatial positioning of teeth primordia in the alligator,Alligator mississippiensis. Detailed embryological studies by Westergaard & Ferguson (1986, 1987, 1990) show that jaw growth plays a crucial role in the developmental patterning of the tooth initiation process. Based on biological data we develop a reaction-diffusion mechanism, which crucially includes domain growth. The model can reproduce the spatial pattern development of the first seven teeth primordia in the lower half jaw ofA. mississippiensis. The results for the precise spatio-temporal sequence compare well with detailed developmental experiments
Visible Light-Promoted Aryl Azoline Formation over Mesoporous Organosilica as Heterogeneous Photocatalyst
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