553 research outputs found
Estado nutricional, características de la vivienda y crianza de animales de traspatio como factores asociados a enteroparasitosis en niños
The aim of this study was to determine the association of enteroparasitosis in school-age children in the Santa María de Chicmo district (Apurímac, Peru) with the nutritional status, characteristics of the house, and raising of backyard animals. Stool samples were taken from 493 children aged 6-16 years, of both sexes, and their homes were visited to determine their characteristics. The prevalence of enteroparasites was 82.4%, where the highest prevalence corresponded to Entamoeba coli (59.6%), followed by Ascaris lumbricoides (51.1%) and Taenia sp with 33.3%. Other parasites presented prevalence less than 12%. The raising of pigs and chickens was associated with Taenia sp and E. vermicularis, respectively. Defecating in the open field, housing on the edge of crops and on the edge of ditches were associated with E. vermicularis, H. nana and A. lumbricoides. Nutritional status was not associated with parasitosis in schoolchildren. It is concluded that the characteristics of the houses and the raising of backyard animals present characteristics that favour the presentation of intestinal parasitism in children in the Santa María de Chicmo district. El objetivo del estudio fue determinar la asociación de la enteroparasitosis en niños en edad escolar del distrito de Santa María de Chicmo (Apurímac, Perú) con el estado nutricional, características de la vivienda y crianza de animales de traspatio. Se tomaron muestras coprológicas a 493 niños de 6-16 años, de ambos sexos y se visitaron sus viviendas para determinar sus características. La prevalencia de enteroparásitos fue de 82.4%, donde la mayor prevalencia correspondió a Entamoeba coli (59.6%), seguida de Ascaris lumbricoides (51.1%), Taenia sp con 33.3%. Otros parásitos presentaron prevalencias menores a 12%. La crianza de porcinos y pollos estuvo asociada a Taenia sp y E. vermicularis, respectivamente. Defecar a campo abierto, vivienda al borde de cultivos y al borde de acequias estuvieron asociados a E. vermicularis, H. nana y A. lumbricoides. El estado nutricional no estuvo asociado a la parasitosis en los escolares. Se concluye que las características de las viviendas y la crianza de animales de traspatio presentan características que favorecen la presentación de parasitismo intestinal en los niños del distrito de Santa María de Chicmo
Measurement of the mass and lifetime of the baryon
A proton-proton collision data sample, corresponding to an integrated
luminosity of 3 fb collected by LHCb at and 8 TeV, is used
to reconstruct , decays. Using the , decay mode for calibration, the lifetime ratio and absolute
lifetime of the baryon are measured to be \begin{align*}
\frac{\tau_{\Omega_b^-}}{\tau_{\Xi_b^-}} &= 1.11\pm0.16\pm0.03, \\
\tau_{\Omega_b^-} &= 1.78\pm0.26\pm0.05\pm0.06~{\rm ps}, \end{align*} where the
uncertainties are statistical, systematic and from the calibration mode (for
only). A measurement is also made of the mass difference,
, and the corresponding mass, which
yields \begin{align*} m_{\Omega_b^-}-m_{\Xi_b^-} &= 247.4\pm3.2\pm0.5~{\rm
MeV}/c^2, \\ m_{\Omega_b^-} &= 6045.1\pm3.2\pm 0.5\pm0.6~{\rm MeV}/c^2.
\end{align*} These results are consistent with previous measurements.Comment: 11 pages, 5 figures, All figures and tables, along with any
supplementary material and additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-008.htm
Study of decays to the final state and evidence for the decay
A study of decays is performed for the first time
using data corresponding to an integrated luminosity of 3.0
collected by the LHCb experiment in collisions at centre-of-mass energies
of and TeV. Evidence for the decay
is reported with a significance of 4.0 standard deviations, resulting in the
measurement of
to
be .
Here denotes a branching fraction while and
are the production cross-sections for and mesons.
An indication of weak annihilation is found for the region
, with a significance of
2.4 standard deviations.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-022.html,
link to supplemental material inserted in the reference
Evidence for the strangeness-changing weak decay
Using a collision data sample corresponding to an integrated luminosity
of 3.0~fb, collected by the LHCb detector, we present the first search
for the strangeness-changing weak decay . No
hadron decay of this type has been seen before. A signal for this decay,
corresponding to a significance of 3.2 standard deviations, is reported. The
relative rate is measured to be
, where and
are the and fragmentation
fractions, and is the branching
fraction. Assuming is bounded between 0.1 and
0.3, the branching fraction would lie
in the range from to .Comment: 7 pages, 2 figures, All figures and tables, along with any
supplementary material and additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-047.htm
Measurement of the lifetime
Using a data set corresponding to an integrated luminosity of ,
collected by the LHCb experiment in collisions at centre-of-mass energies
of 7 and 8 TeV, the effective lifetime in the
decay mode, , is measured to be ps. Assuming
conservation, corresponds to the lifetime of the light
mass eigenstate. This is the first measurement of the effective
lifetime in this decay mode.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-017.htm
flavour tagging using charm decays at the LHCb experiment
An algorithm is described for tagging the flavour content at production of
neutral mesons in the LHCb experiment. The algorithm exploits the
correlation of the flavour of a meson with the charge of a reconstructed
secondary charm hadron from the decay of the other hadron produced in the
proton-proton collision. Charm hadron candidates are identified in a number of
fully or partially reconstructed Cabibbo-favoured decay modes. The algorithm is
calibrated on the self-tagged decay modes and using of data collected by the LHCb
experiment at centre-of-mass energies of and
. Its tagging power on these samples of
decays is .Comment: All figures and tables, along with any supplementary material and
additional information, are available at
http://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-027.htm
Model-independent evidence for contributions to decays
The data sample of decays acquired with the
LHCb detector from 7 and 8~TeV collisions, corresponding to an integrated
luminosity of 3 fb, is inspected for the presence of or
contributions with minimal assumptions about
contributions. It is demonstrated at more than 9 standard deviations that
decays cannot be described with
contributions alone, and that contributions play a dominant role in
this incompatibility. These model-independent results support the previously
obtained model-dependent evidence for charmonium-pentaquark
states in the same data sample.Comment: 21 pages, 12 figures (including the supplemental section added at the
end
Observation of the decay
The decay is observed in collision
data corresponding to an integrated luminosity of 3 fb recorded by the
LHCb detector at centre-of-mass energies of 7 TeV and 8 TeV. This is the first
observation of this decay channel, with a statistical significance of 15
standard deviations. The mass of the meson is measured to be
MeV/c. The branching fraction ratio
is measured to be 0.0115\,\pm\, 0.0012\, ^{+0.0005}_{-0.0009}.
In both cases, the first uncertainty is statistical and the second is
systematic. No evidence for non-resonant or decays is found.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-033.htm
Constraints on the unitarity triangle angle from Dalitz plot analysis of decays
The first study is presented of CP violation with an amplitude analysis of
the Dalitz plot of decays, with , and . The analysis is based on a data sample corresponding to
of collisions collected with the LHCb detector. No
significant CP violation effect is seen, and constraints are placed on the
angle of the unitarity triangle formed from elements of the
Cabibbo-Kobayashi-Maskawa quark mixing matrix. Hadronic parameters associated
with the decay are determined for the first time. These
measurements can be used to improve the sensitivity to of existing and
future studies of the decay.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-059.html;
updated to correct figure 9 (numerical results unchanged
Study of J /ψ production in Jets
The production of J/ψ mesons in jets is studied in the forward region of proton-proton collisions using data collected with the LHCb detector at a center-of-mass energy of 13 TeV. The fraction of the jet transverse momentum carried by the J/ψ meson, z(J/ψ)≡pT(J/ψ)/pT(jet), is measured using jets with pT(jet)>20 GeV in the pseudorapidity range 2.5<η(jet)<4.0. The observed z(J/ψ)distribution for J/ψ mesons produced in b-hadron decays is consistent with expectations. However, the results for prompt J/ψ production do not agree with predictions based on fixed-order nonrelativistic QCD. This is the first measurement of the pT fraction carried by prompt J/ψ mesons in jets at any experiment
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