7,101 research outputs found
Aspectos gerais da fotossensibilizacao hepatogena em bovinos.
A sensibilização da pele a luz devido, geralmente, a ação de certas doenças, plantas ou outras substancias, e denominada fotossensibilizacao (Stedman's Medical 1972). O primeiro registro sobre a ocorrência de fotossensibilizacao hepatogena em bovinos mantidos em pastagens de Brachiaria decumbens, na América do Sul, foi feito na Venezuela (Centro Internacional de Agricultura Tropical 1975), onde a doença ocasionou a morte de doze garrotes nos primeiros dias de pastejo. No Brasil, Hutton (s.d.lL) fez observações sobre casos desta doença no gado Nelore, em pastagens de B. decumbens, em Rio Verde de Goiás. O surto acometeu, principalmente, bezerros antes e depois da desmama. Alem desta primeira constatação, vários outros autores descreveram esta doença em bovinos em pastagem de B. decumbens.bitstream/item/138531/1/COT-19.pdfCNPG
Shape Control for Experimental Continuation
An experimental method has been developed to locate unstable equilibria of
nonlinear structures quasi-statically. The technique involves loading a
structure by application of either a force or a displacement at a main
actuation point, while simultaneously controlling the overall shape using
additional probe points. The method is applied to a shallow arch, and unstable
segments of its equilibrium path are identified experimentally for the first
time. Shape control is a fundamental building block for the experimental---as
opposed to numerical---continuation of nonlinear structures, which will
significantly expand our ability to measure their mechanical response.Comment: Updated Figure 6 experimental results with correct calibration factor
for linear transducer. Updated Figure 6 finite element results with correct
load multiplier for half-model. Updated paper text to reflect these changes.
5 pages, 6 figure
Study of Hg vacancies in (Hg,Cd)Te after THM growth and post-growth annealing by positron annihilation
Positron lifetime measurements have been performed to study vacancy defects in Hg0.78Cd0.22Te. Post-growth annealing under various Hg vapour pressure conditions have been used to create a well-defined number of Hg vacancies. The sensitivity range of the positron annihilation method was found to be 1015 < cHgvac<1018 cm-3. The obtained experience has been used to investigate THM-grown single crystals. The measured longitudinal and radial dependence of the vacancy concentration can be explained by the temperature profile in the grown (Hg,Cd)Te ingots
A steerable UV laser system for the calibration of liquid argon time projection chambers
A number of liquid argon time projection chambers (LAr TPC's) are being build
or are proposed for neutrino experiments on long- and short baseline beams. For
these detectors a distortion in the drift field due to geometrical or physics
reasons can affect the reconstruction of the events. Depending on the TPC
geometry and electric drift field intensity this distortion could be of the
same magnitude as the drift field itself. Recently, we presented a method to
calibrate the drift field and correct for these possible distortions. While
straight cosmic ray muon tracks could be used for calibration, multiple coulomb
scattering and momentum uncertainties allow only a limited resolution. A UV
laser instead can create straight ionization tracks in liquid argon, and allows
one to map the drift field along different paths in the TPC inner volume. Here
we present a UV laser feed-through design with a steerable UV mirror immersed
in liquid argon that can point the laser beam at many locations through the
TPC. The straight ionization paths are sensitive to drift field distortions, a
fit of these distortion to the linear optical path allows to extract the drift
field, by using these laser tracks along the whole TPC volume one can obtain a
3D drift field map. The UV laser feed-through assembly is a prototype of the
system that will be used for the MicroBooNE experiment at the Fermi National
Accelerator Laboratory (FNAL)
Carrapato, tristeza parasitaria e tripanossomose dos bovinos.
Carrapato. O carrapato-do-boi Boophilus microplus: ciclo, biologia e epidemiologia, patogenia e controle. Tristeza parasitaria dos bovinos. Tristeza parasitaria dos bovinos (TPB): conceito, etiologia, transmissao, epidemiologia, diagnostico e controle. Imunidade contra Babesia e Anaplasma. Diagnostico parasitologico da tristeza parasitaria bovina. Diagnostico sorologico da tristeza parasitaria bovina. Diagnostico anatomopatologico da tristeza parasitaria bovina. Trpanossomose Trypanosoma vivax: biologia, diagnostico e controle. Imunidade contra Trypanosoma vivax.bitstream/item/196071/1/Carrapato-tristeza-parasitaria.pd
Epidemiologia do Boophilus microplus nas condições de cerrado.
O carrapato Boophilus microplus (Canestrini 1887), e um parasita temporário e obrigatório dos bovinos. Distribui-se geograficamente entre os paralelos 32 Norte e Sul, tendo ampla distribuição no México, América Central, América do Sul e Austrália.bitstream/item/137546/1/PESQ-EM-ANDAMENTO-23.pd
Measurement of the drift field in the ARGONTUBE LAr TPC with 266~nm pulsed laser beams
ARGONTUBE is a liquid argon time projection chamber (LAr TPC) with a drift
field generated in-situ by a Greinacher voltage multiplier circuit. We present
results on the measurement of the drift-field distribution inside ARGONTUBE
using straight ionization tracks generated by an intense UV laser beam. Our
analysis is based on a simplified model of the charging of a multi-stage
Greinacher circuit to describe the voltages on the field cage rings
Ocorrência de fotossensibilização em equinos mantidos em pastagem de Brachiaria humidicola.
bitstream/item/138780/1/COT-40.pdfCNPGC
Experimental study of electric breakdowns in liquid argon at centimeter scale
In this paper we present results on measurements of the dielectric strength
of liquid argon near its boiling point and cathode-anode distances in the range
of 0.1 mm to 40 mm with spherical cathode and plane anode. We show that at such
distances the applied electric field at which breakdowns occur is as low as 40
kV/cm. Flash-overs across the ribbed dielectric of the high voltage
feed-through are observed for a length of 300 mm starting from a voltage of 55
kV. These results contribute to set reference for the breakdown-free design of
ionization detectors, such as Liquid Argon Time Projection Chambers (LAr TPC)
- …