415 research outputs found
Jaguar (Panthera onca) and puma (Puma concolor) diets in Quintana Roo, Mexico
A study was carried out for two years in Northwest Quintana Roo, México, using scat analysis to determine the diet and prey preferences of pumas and jaguars. Cat species and gender were determined using molecular techniques (rapid classificatory protocol: polymerise chain reaction, RCP–PCR), and prey abundance was estimated from camera trapping. The scats contained remains from 16 wild mammal species, but there was no evidence of livestock or other taxa. The diet breadths of jaguar (0.32) and puma (0.29) indicated a high degree of prey specialization, which combined with their dietary overlap (Pianka index 0.77) suggested competition between them. However, both felids showed a preference for red brocket deer Mazama temama, and frequently consumed collared peccaries Pecari tajacu. The importance of such large ungulates in the felids' diets is similar to the expected patterns of wild meat consumption in rural areas of the Northern Yucatan Peninsula. Therefore, future conservation management plan initiatives should involve local rural communities in the management of sustainable hunting, considering these ungulates are also the felid prey species.
Resumen La dieta del jaguar (Panthera onca) y del puma (Puma concolor) en Quintana Roo, en México.
El estudio se realizó durante dos años en el noroeste de Quintana Roo, en México y se utilizó el análisis de excrementos para determinar la dieta y las preferencias de presas del puma y del jaguar. Se utilizaron técnicas moleculares para identificar la especie de félido y el sexo (protocolo de clasificación rápida: reacción en cadena de la polimerasa, RCP–PCR), y se estimó la abundancia de presas mediante el método de trampeo fotográfico. Los excrementos contenían restos de 16 especies de mamíferos salvajes, pero no se encontraron restos de ganado ni de otros taxones. La amplitud de la dieta del jaguar (0,32) y del puma (0,29) indica que son especies con un alto grado de especialización, lo cual, junto con el traslape de las dietas (índice de Pianka = 0,77) sugiere que ambos félidos compiten entre sí. Asimismo, ambos mostraron preferencia por el venado temazate, Mazama temama, y frecuentemente consumieron pecarí de collar, Pecari tajacu. La importancia de la presencia de este tipo de ungulados en la dieta de los félidos se corresponde con la pauta esperada de consumo de carne de caza en las zonas rurales del norte de la península de Yucatán. Por lo tanto, las futuras iniciativas encaminadas a planificar la conservación de ambos félidos deberían hacer partícipes a las comunidades rurales en la gestión de la cacería sustentable, considerando que estos ungulados también son presas de los félidos
Effect of herbal choline and rumen-protected methionine on lamb performance and blood metabolites
Twenty-four lambs (Pelibuey x East Friesian), weighing 22.7 ± 3.2 kg, were fed a basal diet of corn silage, oat hay, alfalfa hay, and concentrate (60% forage and 40% concentrate). Treatments consisted of oral doses of rumen-protected methionine (RPM) (0 and 1.5 g/day) and herbal choline (biocholine) (0 and 4 g/day) in a completely random block design with factorial arrangement of treatments, where lambs were blocked by sex. The experiment was conducted for 60 days, and measurements of live weight and dry matter intake were obtained. No effects of the treatments were observed on performance variables (lamb growth, consumption and feed conversion). Non-esterified fatty acids (NEFA) were increased by biocholine and unaffected by methionine (Met). Biocholine increased glucose and cholesterol, whereas methionine increased triglycerides, albumin and plasma protein. The dietary supplementation with biocholine and RPM did not improve lambs’ growth; however, biocholine and Met showed a lipotropic effect by mobilizing NEFA and stimulating glucose and cholestrol synthesis.Keywords: feed additives, growing sheep, lipid metabolis
Effect of natural zeolite on live weight changes, ruminal fermentation and nitrogen metabolism of ewe lambs
The objective of this study was to evaluate the effects of natural zeolite on the performance and nitrogen metabolism of Rambouillet ewe lambs. Forty Rambouillet ewe lambs with an initial weight of 41.06 ± 3.9 kg were randomly assigned to one of four experimental diets, namely 0, 20, 40 and 60 g of natural zeolite (Comercializadora Omega® México) per kg dietary dry matter in a completely randomized design and sixteen ewe lambs were used in a 4 x 4 Latin square metabolism study. Performance was not modified by natural zeolite levels in the diet, and daily gain showed a quadratic response. Ammonia concentration at 8 and 12 hours increased linearly with zeolite. Zeolite increased ruminal pH linearly at 8 and 12 hours. Acetate and butyrate presented a quadratic response, and total ruminal volatile fatty acid concentration was linearly increased by zeolite. Nitrogen retention showed a linear and quadratic response to zeolite. The estimated fractions of protein digested in the small intestine, when rumen-fermentable energy was limiting (PDIE) and when rumen-fermentable nitrogen was limiting, showed a linear and quadratic response to zeolite. PDIE was positively correlated (r = 0.96) with average daily gain.Keywords: Sheep, ammonium, ruminal fermentation, productive, soluble nitroge
Evaluation of polyherbal methionine and choline in feedlot rations for lambs
Requirements of lambs for choline and methionine have not been clearly established, but because of their metabolic relationship, the availability of these two nutrients may affect protein synthesis and energy balance. Therefore, a trial was carried out to evaluate the effect on productive performance and blood metabolites of including methionine and choline from polyherbal mixtures in finishing lamb diets. Forty Hampshire x Suffolk lambs weighing 26.9 ± 2.8 kg were used for a 45-day experiment. The treatments were arranged as a 2x2 factorial, in which the factors were dietary supplementation with herbal methionine and choline at two levels (0% and 0.4% of dry matter (DM)). The treatments had no effects on the lambs’ productive variables (daily feed intake, average daily gain, and feed to gain ratio), carcass characteristics and lipid metabolites (P >0.05). The results indicated that the inclusion of polyherbal mixtures containing methionine, choline and their combination at 0.4% of DM in finishing lamb diets showed no benefits in productive response or in blood metabolites related to lipid metabolism.
Keywords: amino acid, lipid metabolites, productive performance, ruminally protected, vitami
Search for single top quarks in the tau+jets channel using 4.8 fb of collision data
We present the first direct search for single top quark production using tau
leptons. The search is based on 4.8 fb of integrated luminosity
collected in collisions at =1.96 TeV with the D0 detector
at the Fermilab Tevatron Collider. We select events with a final state
including an isolated tau lepton, missing transverse energy, two or three jets,
one or two of them tagged. We use a multivariate technique to discriminate
signal from background. The number of events observed in data in this final
state is consistent with the signal plus background expectation. We set in the
tau+jets channel an upper limit on the single top quark cross section of
\TauLimObs pb at the 95% C.L. This measurement allows a gain of 4% in expected
sensitivity for the observation of single top production when combining it with
electron+jets and muon+jets channels already published by the D0 collaboration
with 2.3 fb of data. We measure a combined cross section of
\SuperCombineXSall pb, which is the most precise measurement to date.Comment: 12 pages, 5 figure
b-Jet Identification in the D0 Experiment
Algorithms distinguishing jets originating from b quarks from other jet
flavors are important tools in the physics program of the D0 experiment at the
Fermilab Tevatron p-pbar collider. This article describes the methods that have
been used to identify b-quark jets, exploiting in particular the long lifetimes
of b-flavored hadrons, and the calibration of the performance of these
algorithms based on collider data.Comment: submitted to Nuclear Instruments and Methods in Physics Research
Measurement of the dijet invariant mass cross section in proton anti-proton collisions at sqrt{s} = 1.96 TeV
The inclusive dijet production double differential cross section as a
function of the dijet invariant mass and of the largest absolute rapidity of
the two jets with the largest transverse momentum in an event is measured in
proton anti-proton collisions at sqrt{s} = 1.96 TeV using 0.7 fb^{-1}
integrated luminosity collected with the D0 detector at the Fermilab Tevatron
Collider. The measurement is performed in six rapidity regions up to a maximum
rapidity of 2.4. Next-to-leading order perturbative QCD predictions are found
to be in agreement with the data.Comment: Published in Phys. Lett. B, 693, (2010), 531-538, 8 pages, 2 figures,
6 table
Measurement of Z/gamma*+jet+X angular distributions in ppbar collisions at sqrt{s}=1.96 TeV
We present the first measurements at a hadron collider of differential cross
sections for Z+jet+X production in delta phi(Z, jet), |delta y(Z, jet)| and
|y_boost(Z, jet)|. Vector boson production in association with jets is an
excellent probe of QCD and constitutes the main background to many small cross
section processes, such as associated Higgs production. These measurements are
crucial tests of the predictions of perturbative QCD and current event
generators, which have varied success in describing the data. Using these
measurements as inputs in tuning event generators will increase the
experimental sensitivity to rare signals.Comment: Published in Physics Letters B 682 (2010), pp. 370-380. 15 pages, 6
figure
Search for the standard model Higgs boson in tau final states
We present a search for the standard model Higgs boson using hadronically
decaying tau leptons, in 1 inverse femtobarn of data collected with the D0
detector at the Fermilab Tevatron ppbar collider. We select two final states:
tau plus missing transverse energy and b jets, and tau+ tau- plus jets. These
final states are sensitive to a combination of associated W/Z boson plus Higgs
boson, vector boson fusion and gluon-gluon fusion production processes. The
observed ratio of the combined limit on the Higgs production cross section at
the 95% C.L. to the standard model expectation is 29 for a Higgs boson mass of
115 GeV.Comment: publication versio
Search for W' bosons decaying to an electron and a neutrino with the D0 detector
This Letter describes the search for a new heavy charged gauge boson W'
decaying into an electron and a neutrino. The data were collected with the D0
detector at the Fermilab Tevatron proton-antiproton Collider at a
center-of-mass energy of 1.96 TeV, and correspond to an integrated luminosity
of about 1 inverse femtobarn. Lacking any significant excess in the data in
comparison with known processes, an upper limit is set on the production cross
section times branching fraction, and a W' boson with mass below 1.00 TeV can
be excluded at the 95% C.L., assuming standard-model-like couplings to
fermions. This result significantly improves upon previous limits, and is the
most stringent to date.Comment: submitted to Phys. Rev. Let
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