219 research outputs found
One-sided Cauchy-Stieltjes Kernel Families
This paper continues the study of a kernel family which uses the
Cauchy-Stieltjes kernel in place of the celebrated exponential kernel of the
exponential families theory. We extend the theory to cover generating measures
with support that is unbounded on one side. We illustrate the need for such an
extension by showing that cubic pseudo-variance functions correspond to
free-infinitely divisible laws without the first moment. We also determine the
domain of means, advancing the understanding of Cauchy-Stieltjes kernel
families also for compactly supported generating measures
Geodynamo and mantle convection simulations on the Earth Simulator using the Yin-Yang grid
We have developed finite difference codes based on the Yin-Yang grid for the
geodynamo simulation and the mantle convection simulation. The Yin-Yang grid is
a kind of spherical overset grid that is composed of two identical component
grids. The intrinsic simplicity of the mesh configuration of the Yin-Yang grid
enables us to develop highly optimized simulation codes on massively parallel
supercomputers. The Yin-Yang geodynamo code has achieved 15.2 Tflops with 4096
processors on the Earth Simulator. This represents 46% of the theoretical peak
performance. The Yin-Yang mantle code has enabled us to carry out mantle
convection simulations in realistic regimes with a Rayleigh number of
including strongly temperature-dependent viscosity with spatial contrast up to
.Comment: Plenary talk at SciDAC 200
Quantum Free Yang-Mills on the Plane
We construct a free-probability quantum Yang-Mills theory on the two
dimensional plane, determine the Wilson loop expectation values, and show that
this theory is the limit of U(N) quantum Yang-Mills theory on the
plane.Comment: 24 pages, tikz figure
The Psyche Gravity Investigation
The objective of the NASA Psyche mission gravity science investigation is to map the mass distribution within asteroid (16) Psyche to elucidate interior structure and to resolve the question of whether this metal-rich asteroid represents a remnant metal core or whether it is a primordial body that never melted. Measurements of gravity will be obtained via the X-band telecommunication system on the Psyche spacecraft, collected from progressively lower mapping altitudes. Orbital gravity will allow an estimate of GM to better than 0.001 km3 s−2. A spherical harmonic model of gravity to degree and order 10 will be achievable and, in concert with spherical harmonic data sets from topography and magnetometry, as well as surface composition data, will provide information regarding the spatial and radial distribution of mass that will be used to constrain the origin and evolution of (16) Psyche
Rigorous mean field model for CPA: Anderson model with free random variables
A model of a randomly disordered system with site-diagonal random energy
fluctuations is introduced. It is an extension of Wegner's -orbital model to
arbitrary eigenvalue distribution in the electronic level space. The new
feature is that the random energy values are not assumed to be independent at
different sites but free. Freeness of random variables is an analogue of the
concept of independence for non-commuting random operators. A possible
realization is the ensemble of at different lattice-sites randomly rotated
matrices. The one- and two-particle Green functions of the proposed hamiltonian
are calculated exactly. The eigenstates are extended and the conductivity is
nonvanishing everywhere inside the band. The long-range behaviour and the
zero-frequency limit of the two-particle Green function are universal with
respect to the eigenvalue distribution in the electronic level space. The
solutions solve the CPA-equation for the one- and two-particle Green function
of the corresponding Anderson model. Thus our (multi-site) model is a rigorous
mean field model for the (single-site) CPA. We show how the Llyod model is
included in our model and treat various kinds of noises.Comment: 24 pages, 2 diagrams, Rev-Tex. Diagrams are available from the
authors upon reques
Torsion of a cylinder of partially molten rock with a spherical inclusion: Theory and simulation
The processes that are involved in migration and extraction of melt from the
mantle are not yet fully understood. Gaining a better understanding of material
properties of partially molten rock could help shed light on the behavior of
melt on larger scales in the mantle. In this study, we simulate
three-dimensional torsional deformation of a partially molten rock that
contains a rigid, spherical inclusion. We compare the computed porosity
patterns to those found in recent laboratory experiments. The laboratory
experiments show emergence of melt-rich bands throughout the rock sample, and
pressure shadows around the inclusion. The numerical model displays similar
melt-rich bands only for a small bulk-to-shear-viscosity ratio (five or less).
The results are consistent with earlier two-dimensional numerical simulations;
however, we show that it is easier to form melt-rich bands in three dimensions
compared to two. The addition of strain-rate dependence of the viscosity causes
a distinct change in the shape of pressure shadows around the inclusion. This
change in shape presents an opportunity for experimentalists to identify the
strain-rate dependence and therefore the dominant deformation mechanism in
torsion experiments with inclusions.This work was supported by the UK Natural Environment Research Council under grants NE/I023929/1 and NE/I026995/1. Computations were performed on the ARCHER UK National Supercomputing Service (http://www.archer.ac.uk). We thank Chris Richardson for all his support with running the simulations on ARCHER. Katz thanks the Leverhulme Trust for support.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/2015GC00606
Fetal loss and maternal serum levels of 2,2',4,4',5,5'-hexachlorbiphenyl (CB-153) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE) exposure: a cohort study in Greenland and two European populations
<p>Abstract</p> <p>Background</p> <p>In the present study, the aim is to examine the risk of fetal loss related to environmental 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) or 1,1-dichloro-2,2-bis(<it>p</it>-chlorophenyl)ethylene (p,p'-DDE) exposure.</p> <p>Methods</p> <p>We related LC/MS/MS measurements of CB-153 and p,p'-DDE in serum samples to interview-data on previous fetal loss in populations of pregnant women from Poland, Ukraine and Greenland.</p> <p>Results</p> <p>In total, 1710 women were interviewed, and 678 of these had at least one previous pregnancy. The risk of ever experiencing a fetal loss increased at higher levels of CB-153 and p,p'-DDE exposure, with an adjusted odds ratio (OR) of 2.4; confidence interval (CI) (1.1-5.5) for CB-153>200 ng/g lipid compared to 0-25 ng CB-153/g lipid and OR of 2.5 CI (0.9-6.6) for p,p'-DDE>1500 ng/g lipid compared to 0-250 ng DDE/g lipid. However, no clear dose response associations were observed. The results further suggest that high level of organochlorine serum concentrations may be related to repeated loss.</p> <p>Conclusions</p> <p>The risk of fetal loss may increase at higher levels of CB-153 and p,p'-DDE exposure, although lack of dose response and inconsistencies between countries did not allow for firm conclusions.</p
Clinical Validation of Integrated Nucleic Acid and Protein Detection on an Electrochemical Biosensor Array for Urinary Tract Infection Diagnosis
BACKGROUND: Urinary tract infection (UTI) is a common infection that poses a substantial healthcare burden, yet its definitive diagnosis can be challenging. There is a need for a rapid, sensitive and reliable analytical method that could allow early detection of UTI and reduce unnecessary antibiotics. Pathogen identification along with quantitative detection of lactoferrin, a measure of pyuria, may provide useful information towards the overall diagnosis of UTI. Here, we report an integrated biosensor platform capable of simultaneous pathogen identification and detection of urinary biomarker that could aid the effectiveness of the treatment and clinical management. METHODOLOGY/PRINCIPAL FINDINGS: The integrated pathogen 16S rRNA and host lactoferrin detection using the biosensor array was performed on 113 clinical urine samples collected from patients at risk for complicated UTI. For pathogen detection, the biosensor used sandwich hybridization of capture and detector oligonucleotides to the target analyte, bacterial 16S rRNA. For detection of the protein biomarker, the biosensor used an analogous electrochemical sandwich assay based on capture and detector antibodies. For this assay, a set of oligonucleotide probes optimized for hybridization at 37°C to facilitate integration with the immunoassay was developed. This probe set targeted common uropathogens including E. coli, P. mirabilis, P. aeruginosa and Enterococcus spp. as well as less common uropathogens including Serratia, Providencia, Morganella and Staphylococcus spp. The biosensor assay for pathogen detection had a specificity of 97% and a sensitivity of 89%. A significant correlation was found between LTF concentration measured by the biosensor and WBC and leukocyte esterase (p<0.001 for both). CONCLUSION/SIGNIFICANCE: We successfully demonstrate simultaneous detection of nucleic acid and host immune marker on a single biosensor array in clinical samples. This platform can be used for multiplexed detection of nucleic acid and protein as the next generation of urinary tract infection diagnostics
Dendritic Cells Crosspresent Antigens from Live B16 Cells More Efficiently than from Apoptotic Cells and Protect from Melanoma in a Therapeutic Model
Dendritic cells (DC) are able to elicit anti-tumoral CD8+ T cell responses by cross-presenting exogenous antigens in association with major histocompatibility complex (MHC) class I molecules. Therefore they are crucial actors in cell-based cancer immunotherapy. Although apoptotic cells are usually considered to be the best source of antigens, live cells are also able to provide antigens for cross-presentation by DC. We have recently shown that prophylactic immunotherapy by DC after capture of antigens from live B16 melanoma cells induced strong CD8+ T-cell responses and protection against a lethal tumor challenge in vivo in C57Bl/6 mice. Here, we showed that DC cross-presenting antigens from live B16 cells can also inhibit melanoma lung dissemination in a therapeutic protocol in mice. DC were first incubated with live tumor cells for antigen uptake and processing, then purified and irradiated for safety prior to injection. This treatment induced stronger tumor-specific CD8+ T-cell responses than treatment by DC cross-presenting antigens from apoptotic cells. Apoptotic B16 cells induced more IL-10 secretion by DC than live B16 cells. They underwent strong native antigen degradation and led to the expression of fewer MHC class I/epitope complexes on the surface of DC than live cells. Therefore, the possibility to use live cells as sources of tumor antigens must be taken into account to improve the efficiency of cancer immunotherapy
- …