109 research outputs found
Living on the margins : illness and healthcare among Peruvian migrants in Chile
UBL - phd migration 201
Fourier Method for Approximating Eigenvalues of Indefinite Stekloff Operator
We introduce an efficient method for computing the Stekloff eigenvalues
associated with the Helmholtz equation. In general, this eigenvalue problem
requires solving the Helmholtz equation with Dirichlet and/or Neumann boundary
condition repeatedly. We propose solving the related constant coefficient
Helmholtz equation with Fast Fourier Transform (FFT) based on carefully
designed extensions and restrictions of the equation. The proposed Fourier
method, combined with proper eigensolver, results in an efficient and clear
approach for computing the Stekloff eigenvalues.Comment: 12 pages, 4 figure
Infrared spectra of one- and two-dimensional fullerene polymer structures: RbC60 and rhombohedral C-60
We compare the infrared spectra of two types of fullerene polymers: the linear-chain RbC60 and the two-dimensional pressure-polymerized rhombohedral C-60. Both the splitting of the F-1u modes and the structure of newly activated Lines are in agreement with fully ordered structures of molecular symmetry D-2h and D-3d, respectively
Coagulation Tests and Selected Biochemical Analytes in Dairy Cows with Hepatic Lipidosis
The aim of this study was to determine the values and changes in conventional and optimised clotting tests, as well as in selected biochemical analytes during hepatic lipidosis in postpartum dairy cows. Ten healthy and ten Holstein cows with hepatic lipidosis were selected based upon clinical history, clinical examination, liver biopsy, flotation test and histological analysis of hepatic tissue. Prothrombin time (PT) and partial thromboplastin time (PTT) were determined in non-diluted and diluted blood plasma samples. Clotting times determined in diluted plasma samples were prolonged in cows with hepatic lipidosis and there was a difference in the PT value at both 50% and 25% plasma dilutions between both groups of animals (P = 0.004 and P = 0.001). Significant differences between healthy animals and cows with hepatic lipidosis were observed in blood serum values for free fatty acids (FFA), aspartate aminotransferase (AST) and triacyglycerols (P = 0.001, P = 0.007 and P = 0.044), respectively. FFA and liver biopsy are better diagnostic indicators for hepatic lipidosis than coagulation tests. The optimised PT is prolonged in cows with hepatic lipidosis and can detect this alteration that cannot be appreciated using conventional PT test
General Brane Geometries from Scalar Potentials: Gauged Supergravities and Accelerating Universes
We find broad classes of solutions to the field equations for d-dimensional
gravity coupled to an antisymmetric tensor of arbitrary rank and a scalar field
with non-vanishing potential. Our construction generates these configurations
from the solution of a single nonlinear ordinary differential equation, whose
form depends on the scalar potential. For an exponential potential we find
solutions corresponding to brane geometries, generalizing the black p-branes
and S-branes known for the case of vanishing potential. These geometries are
singular at the origin with up to two (regular) horizons. Their asymptotic
behaviour depends on the parameters of the model. When the singularity has
negative tension or the cosmological constant is positive we find
time-dependent configurations describing accelerating universes. Special cases
give explicit brane geometries for (compact and non-compact) gauged
supergravities in various dimensions, as well as for massive 10D supergravity,
and we discuss their interrelation. Some examples lift to give new solutions to
10D supergravity. Limiting cases with a domain wall structure preserve part of
the supersymmetries of the vacuum. We also consider more general potentials,
including sums of exponentials. Exact solutions are found for these with up to
three horizons, having potentially interesting cosmological interpretation. We
give several additional examples which illustrate the power of our techniques.Comment: 54 pages, 6 figures. Uses JHEP3. Published versio
The Cauchy problem of f(R) gravity
The initial value problem of metric and Palatini f(R)gravity is studied by
using the dynamical equivalence between these theories and Brans-Dicke gravity.
The Cauchy problem is well-formulated for metric f(R)gravity in the presence of
matter and well-posed in vacuo. For Palatini f(R)gravity, instead, the Cauchy
problem is not well-formulated.Comment: 16 latex pages, to appear in Class. Quantum Grav; typographical
errors corrected, new references adde
Efeito do estresse hídrico sobre a germinação de sementes pinhão-manso (Jatropha Curcas, L.).
Invasion of Ureaplasma diversum in bovine spermatozoids
<p>Abstract</p> <p>Background</p> <p><it>Ureaplasma diversum </it>has been associated with infertility in cows. In bulls, this mollicute colonizes the prepuce and distal portion of the urethra and may infect sperm cells. The aim of this study is to analyze <it>in vitro </it>interaction of <it>U. diversum </it>isolates and ATCC strains with bovine spermatozoids. The interactions were observed by confocal microscopy and the gentamycin internalization assay.</p> <p>Findings</p> <p><it>U. diversum </it>were able to adhere to and invade spermatozoids after 30 min of infection. The gentamicin resistance assay confirmed the intracellularity and survival of <it>U. diversum </it>in bovine spermatozoids.</p> <p>Conclusions</p> <p>The intracellular nature of bovine ureaplasma identifies a new difficulty to control the reproductive of these animals.</p
Ground-based CCD astrometry with wide field imagers. III. [email protected] proper-motion catalog of the globular cluster omega Centauri
Omega Centauri is the most well studied Globular Cluster because of its
numerous puzzling features. Intensive spectroscopic follow-up observing
campaigns targeting stars at different positions on the color-magnitude diagram
promises to clarify some of these peculiarities. To able to target cluster
members reliably during spectroscopic surveys and both spatial and radial
distributions in the cluster outskirts without including field stars, a high
quality proper-motion catalog of omega Cen and membership probability
determination are required. The only available wide field proper-motion catalog
of omega Cen is derived from photographic plates, and only for stars brighter
than B~16. Using ESO archive data, we create a new, CCD-based, proper-motion
catalog for this cluster, extending to B~20. We used the high precision
astrometric software developed specifically for data acquired by [email protected]
telescope and presented in the first paper of this series. We achieved a good
cluster-field separation with a temporal base-line of only four years. We
corrected our photometry for sky-concentration effects. We provide calibrated
photometry for UBVRI wide-band data plus narrow-band filter data centered on
H_alpha for almost 360 000 stars. We can confirm that the omega Cen metal-poor
and the metal-rich components have the same proper motion, and demonstrate that
the metal-intermediate component in addition exhibits the same mean motion as
the other RGB stars. We provided membership probability determination for
published omega Cen variable star catalogs. Our catalog extends the
proper-motion measurements to fainter than the cluster turn-off luminosity, and
covers a wide area (~33'x33') around the center of omega Cen. Our catalog is
now electronically available to the astronomical community.Comment: 21 pages, 15 figures (8 in low resolution), shortened abstract,
revised version, accepted (October 3rd, 2008) for publication in A&
A SOLUBILIDADE DOS COMPOSTOS IÔNICOS: COMO OS LICENCIANDOS EM QUÍMICA EXPLICAM O COMPORTAMENTO DO CLORETO DE PRATA?
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