218 research outputs found
Pré-compostagem de cadáveres de bovinos acometidos pelo botulismo.
Foram pré-compostados, em células individuais e isoladas, cinco cadáveres de bovinos acometidos pelo botulismo com a finalidade de monitorar a presença de esporos de Clostridium botulinum e de toxina botulínica antes e após o processo de decomposição em leira estática com fonte de carbono. O diagnóstico da intoxicação nos animais foi baseado nas características clínico-patológicas, epidemiológicas ou laboratoriais. Dos cinco bovinos com evolução clínica crônica de botulismo, cujos cadáveres foram pré-compostados, três foram acometidos pela toxina tipo D, um pelo complexo CD e um dos animais foi negativo na tentativa de detecção da toxina e de esporos da bactéria nas vísceras pelo bioensaio e neutralização em camundongo. O processo de pré-compostagem foi realizado em leira estática, com o uso de material carbonáceo umidificado como substrato e esquartejamento do animal, vedado individualmente com lona plástica e sem aeração por um período de 50 dias. A temperatura das leiras foi monitorada durante o período e oscilou de 40,5-52,4ºC. Após a abertura das leiras, pôde-se constatar a completa decomposição de todo material mole, com redução significativa do seu peso (de 26,5-44,5%), restando apenas os ossos. Não foi detectado esporo ou toxina botulínica no interior dos ossos (n=5 para cada cadáver). Nas 200 amostras examinadas do homogeneizado restante (n=40 para cada cadáver), em apenas duas amostras de uma leira foram detectados esporos de C. botulinum tipo C, enquanto que todas foram negativas para a tentativa de detecção da toxina botulínica pelo bioensaio em camundongo. Da forma como foi avaliado o processo de pré-compostagem de bovinos mortos pela intoxicação botulínica não contribuiu para a proliferação de C. botulinum. Five carcasses of cattle that died from botulism were composted in individual isolated beds with the purpose of monitoring the effect on spores of Clostridium botulinum and of botulinum toxin. The diagnosis of botulinum poisoning was based on clinical and pathological, epidemic and/or laboratorial characteristics. Of the five bovines with clinical signs of chronic botulism, three were affected by the type D toxin, one by the CD complex, and one was negative for toxin and spores of C. botulinum in the viscera using a mouse bioassay. The composting process was carried out in beds with carcasses cut up and mixed with sawdust as a carbon source. They were kept anaerobic under a plastic sheet for 50 days. The temperature of the beds was monitored during the period and oscillated from 40.5 to 52.4ºC. After this time, soft tissue had complete decomposed with a significant loss of weight (26.5-44.5%). The remaining bones no longer contained spores or botulinum toxin in the 5 samples taken from each carcass. Only 2 of the 200 samples of homogenized remaining (40 for each carcass) contained spores of C. botulinum type C. All samples were negative for botulinum toxin using the mouse bioassay. Composting carcasses of cattle that died from botulism eliminated botulinum spores and toxin from the remains
Investigação do manejo e do controle de verminose em criações de ovinos no Estado de São Paulo.
A ovinocultura é uma atividade que desperta enorme interesse como alternativa viável de agronegócio, principalmente para as pequenas e médias propriedades rurais e para a agricultura familiar (CUNHA et al., 2004). Nos últimos anos, em São Paulo, tem-se verifi cado aumento signifi cativo do rebanho ovino e de propriedades envolvidas nessa atividade. Enquanto no período de 1970 a 2008 o rebanho ovino brasileiro passou por redução de 5,75% no número de cabeças (de 17.643.004 para 16.628.571 animais), no Estado de São Paulo o número de animais aumentou em 361,9% (de 98.126 para 453.261). Apesar do grande crescimento nos últimos anos, o rebanho ovino paulista representa somente 2,7% do rebanho nacional (PRODUÇÃO, 2010).bitstream/CPPSE-2010/19363/1/PROCISCMN2010.00022.pd
Two loop effective potential for < A^2_\mu > in the Landau gauge in quantum chromodynamics
We construct the effective potential for the dimension two composite operator
1/2 A^{a 2}_\mu in QCD with massless quarks in the Landau gauge for an
arbitrary colour group at two loops. For SU(3) we show that an estimate for the
effective gluon mass decreases as N_f increases.Comment: 17 latex page
Off-diagonal parton distributions and their evolution
We construct off-diagonal parton distributions defined on the interval 0 < X
< 1 starting from the off-forward distributions defined by Ji. We emphasize the
particular role played by the symmetry relations in the "ERBL-like" region. We
find the evolution equations for the off-diagonal distributions which conserve
these symmetries. We present numerical results of the evolution, and verify
that the analytic asymptotic forms of the parton distributions are reproduced.
We also compare the constructed off-diagonal distributions with the non-forward
distributions defined by Radyushkin and comment on the singularity structure of
the basic amplitude written in terms of the off-diagonal distributions.Comment: 22 pages, Latex, 6 ps figures. Improved presentation after
discussions with X.Ji and A.Radyushki
Renormalizing a BRST-invariant composite operator of mass dimension 2 in Yang-Mills theory
We discuss the renormalization of a BRST and anti-BRST invariant composite
operator of mass dimension 2 in Yang-Mills theory with the general BRST and
anti-BRST invariant gauge fixing term of the Lorentz type. The interest of this
study stems from a recent claim that the non-vanishing vacuum condensate of the
composite operator in question can be an origin of mass gap and quark
confinement in any manifestly covariant gauge, as proposed by one of the
authors. First, we obtain the renormalization group flow of the Yang-Mills
theory. Next, we show the multiplicative renormalizability of the composite
operator and that the BRST and anti-BRST invariance of the bare composite
operator is preserved under the renormalization. Third, we perform the operator
product expansion of the gluon and ghost propagators and obtain the Wilson
coefficient corresponding to the vacuum condensate of mass dimension 2.
Finally, we discuss the connection of this work with the previous works and
argue the physical implications of the obtained results.Comment: 49 pages, 35 eps-files, A number of typographic errors are corrected.
A paragraph is added in the beginning of section 5.3. Two equations (7.1) and
(7.2) are added. A version to be published in Phys. Rev.
Q2-evolution of parton densities at small-x values
In the leading twist approximation of the Wilson operator product expansion
with "frozen" and analytic strong coupling constants we show that
Bessel-inspired behavior of the structure function F2 at small x, obtained for
a flat initial condition in the DGLAP evolution equations, leads to good
agreement with the deep inelastic scattering experimental data from HERA.Comment: 19 pages, 5 figures, published in the Proceedings of Workshop on
Physics of Fundamental Interactions, Institute of High Energy Physics,
Protvino, Russia, 22--25 December 2008 (Phys.Atom.Nucl. in press
Notoph Gauge Theory: Superfield Formalism
We derive absolutely anticommuting Becchi-Rouet-Stora-Tyutin (BRST) and
anti-BRST symmetry transformations for the 4D free Abelian 2-form gauge theory
by exploiting the superfield approach to BRST formalism. The antisymmetric
tensor gauge field of the above theory was christened as the "notoph" (i.e. the
opposite of "photon") gauge field by Ogievetsky and Palubarinov way back in
1966-67. We briefly outline the problems involved in obtaining the absolute
anticommutativity of the (anti-) BRST transformations and their resolution
within the framework of geometrical superfield approach to BRST formalism. One
of the highlights of our results is the emergence of a Curci-Ferrari type of
restriction in the context of 4D Abelian 2-form (notoph) gauge theory which
renders the nilpotent (anti-) BRST symmetries of the theory to be absolutely
anticommutative in nature.Comment: LaTeX file, 12 pages, Talk delivered at SQS'09 (BLTP, JINR, Dubna
The longitudinal structure function F_L: perturbative QCD and k_T-factorization versus experimental data at fixed W
We use results for the structure functions for a gluon target having
nonzero transverse momentum square at order , obtained in our
previous paper, to compare with recent H1 experimental data for at fixwd
W values and with collinear GRV predictions at LO and NLO approximation.Comment: 10 pages, 4 figure
Optimal Renormalization Scale and Scheme for Exclusive Processes
We use the BLM method to fix the renormalization scale of the QCD coupling in
exclusive hadronic amplitudes such as the pion form factor and the
photon-to-pion transition form factor at large momentum transfer.
Renormalization-scheme-independent commensurate scale relations are established
which connect the hard scattering subprocess amplitudes that control exclusive
processes to other QCD observables such as the heavy quark potential and the
electron-positron annihilation cross section. The commensurate scale relation
connecting the heavy quark potential, as determined from lattice gauge theory,
to the photon-to-pion transition form factor is in excellent agreement with
data assuming that the pion distribution amplitude is
close to its asymptotic form . We also reproduce the
scaling and normalization of the data at large
momentum transfer. Because the renormalization scale is small, we argue that
the effective coupling is nearly constant, thus accounting for the nominal
scaling behavior of the data. However, the normalization of the space-like pion
form factor obtained from electroproduction experiments is
somewhat higher than that predicted by the corresponding commensurate scale
relation. This discrepancy may be due to systematic errors introduced by the
extrapolation of the electroproduction data to the
pion pole.Comment: 22 pages, Latex, 7 Latex figures. Several references added,
discussion of scale fixing revised for clarity. Final version to appear in
Phys. Rev.
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