795 research outputs found
Regularization Independent Analysis of the Origin of Two Loop Contributions to N=1 Super Yang-Mills Beta Function
We present a both ultraviolet and infrared regularization independent
analysis in a symmetry preserving framework for the N=1 Super Yang-Mills beta
function to two loop order. We show explicitly that off-shell infrared
divergences as well as the overall two loop ultraviolet divergence cancel out
whilst the beta function receives contributions of infrared modes.Comment: 7 pages, 2 figures, typos correcte
Sorovares de Salmonella isolados de humanos no Estado de São Paulo, Brasil, 1996-2003
A salmonelose permanece uma importante causa de doença diarréica em humanos no Estado de São Paulo, Brasil. Nesse estudo foram identificados 3554 isolados de Salmonella de infecções humanas, durante o período 1996-2003. Entre os 68 diferentes sorovares determinados, S. Enteritidis foi predominante em infecções gastrointestinais e extra-intestinais, responsável por 67.4% de todos os isolados. S. Typhimurium e S. enterica subsp. enterica (4,5,12:i:-) foram mais freqüentemente isolados de crianças com idade de < 1 a 4 anos, em contraste, infecções por S. Enteritidis foram predominantes em pessoas entre 20 e 50 anos. A contínua vigilância laboratorial das salmoneloses, incluindo a sorotipagem, tem evidenciado os sorovares de Salmonella causando infecções humanas em nossa área geográfica ao longo do tempo.Salmonellosis remains an important cause of diarrheal illness in humans in São Paulo State, Brazil. In this study were identified 3554 Salmonella isolates from human infections, during the period 1996-2003. Among 68 different serovars determined, S. Enteritidis was the most frequent one in gastrointestinal and extra-intestinal infections accounting for 67.4% of all isolates. S. Typhimurium and S. enterica subsp. enterica (4,5,12:i:-) were most frequently isolated from children aged < 1-4 year-old, in contrast, people with S. Enteritidis infections were most likely to be 20-50 year-old. In our geographic area the continued laboratorial surveillance of salmonellosis, including serotyping, has showed the trends in Salmonella serovars causing infections in humans throughout the time
Evaluation of mitochondrial activity in spermatozoids after collecting and posthawing in Boer and Alpine goats in autumn and spring
Caprine spermatozoa undergo glycolisis and mitocondrial respiration to keep the necessary
energy balance to their transportation and other cellular functions. An objective test to evaluate
quantitatively and qualitatively mitochondrial activity in caprine spermatozoa was applied in the analysis
of semen samples of 9 bucks from Boer (n=5) and Alpine (n=4) breeds. Samples were collected and
frozen in TRIS medium in two different year seasons. Semen collection was performed using artificial
vagina to obtain 135 ejaculates, which were used to post-collection and post-frozen extended in sildes.
To determine mitochondrial activity, a citochemical procedure developed and validated for HRUDKA
(1987) was used. The technique is based on the enzymatic 3,3-diaminobenzidine (DAB) oxidation,
where the reagent is polymerized and attached to the mitochondrial membrane throughout the spermatic
intermediary piece. A medium level of citochemical activity (IAC) was determined as being 74,37%,
74,37% during Autumn and 77% e 77,75% during Spring for Boer and Alpine breeds, respectively. For
post-collection IAC levels were 85,62% and 85,93 and for post-frozen 66% and 67,25% for Boer and
Alpine breeds, respectively. ANOVA test was used to evaluate breed, post-collection, post-frozen, IAC
rates and year season parameters. Differences were not noticed for breed, IAC rates and year season.
Nonetheless, there was a significant effect among samples for post-collection and post-frozen analysis
(POs espermatozóides caprinos realizam a respiração mitocondrial, mantendo um balanço energético
necessário para o transporte e as demais funções celulares. Um teste objetivo de avaliação quantitativa e
qualitativa da atividade mitocondrial em espermatozóides caprinos foi aplicado no sêmen de nove reprodutores
das raças Boer (n=5) e Alpina (n=4) colhidos e congelados em diluidor TRIS em duas estações. A colheita do
sêmen foi realizada com auxílio da vagina artificial, totalizando 135 ejaculados e foram confeccionados
esfregaços com sêmen pós-colheita e pós-descongelação. Para a determinação da atividade mitocondrial foi
utilizado o procedimento citoquímico desenvolvido e validado por HRUDKA (1987). Esta técnica é baseada
na oxidação da 3,3-diaminobenzidine (DAB) pela enzima em reação em cadeia, onde o reagente é polimerizado
e depositado na bainha mitocondrial ao longo da peça intermediária dos espermatozóides. Foi determinado
um índice médio de atividade citoquímica (IAC) de 74,37%, 74,37% no outono, 77% e 77,75% na primavera.
E 85,62% e 85,93 no pós-colheita, 66% e 67,25% pós-descongelação para as raças Boer e Alpina,
respectivamente. As variáveis raças, pós-colheita e pós-descongelação, classes (IAC), e estação foram
estudadas por meio de ANOVA. Não foram observadas diferenças estatísticas para raças, classes, bem
como para as estações. Entretanto, efeito significativo entre as amostras pós-colheita e pós-descongelação
(
Implementation of an Optimal First-Order Method for Strongly Convex Total Variation Regularization
We present a practical implementation of an optimal first-order method, due
to Nesterov, for large-scale total variation regularization in tomographic
reconstruction, image deblurring, etc. The algorithm applies to -strongly
convex objective functions with -Lipschitz continuous gradient. In the
framework of Nesterov both and are assumed known -- an assumption
that is seldom satisfied in practice. We propose to incorporate mechanisms to
estimate locally sufficient and during the iterations. The mechanisms
also allow for the application to non-strongly convex functions. We discuss the
iteration complexity of several first-order methods, including the proposed
algorithm, and we use a 3D tomography problem to compare the performance of
these methods. The results show that for ill-conditioned problems solved to
high accuracy, the proposed method significantly outperforms state-of-the-art
first-order methods, as also suggested by theoretical results.Comment: 23 pages, 4 figure
Symmetry preserving regularization with a cutoff
A Lorentz and gauge symmetry preserving regularization method is proposed in
4 dimension based on momentum cutoff. We use the conditions of gauge invariance
or freedom of shift of the loop-momentum to define the evaluation of the terms
carrying Lorentz indices, e.g. proportional to k_{\mu}k_{\nu}. The remaining
scalar integrals are calculated with a four dimensional momentum cutoff. The
finite terms (independent of the cutoff) are unambiguous and agree with the
result of dimensional regularization.Comment: 12 pages, 1 figure, v2 references adde
On the equivalence between Implicit Regularization and Constrained Differential Renormalization
Constrained Differential Renormalization (CDR) and the constrained version of
Implicit Regularization (IR) are two regularization independent techniques that
do not rely on dimensional continuation of the space-time. These two methods
which have rather distinct basis have been successfully applied to several
calculations which show that they can be trusted as practical, symmetry
invariant frameworks (gauge and supersymmetry included) in perturbative
computations even beyond one-loop order.
In this paper, we show the equivalence between these two methods at one-loop
order. We show that the configuration space rules of CDR can be mapped into the
momentum space procedures of Implicit Regularization, the major principle
behind this equivalence being the extension of the properties of regular
distributions to the regularized ones.Comment: 16 page
Effects of Enteral Fluid Therapy in Continuous Flow Administered by Nasogastric Tube in Buffalo Calves
To investigate the employment of enteral fluid therapy in continuous flow administered by a nasogastric tube in buffalo calves; toassesstheeffectsof a hypotonic and an isotonic electrolyte solutionon: vital functions, blood count and serum andurinary biochemistry profile of buffalo calves. Seven buffalo calves, clinically healthy, were submitted to two treatments. The solutions were administered in continuous flow through a nasogastric tube at a dose of 15 mL/kg/hr for 12 hours. The serum biochemistry profile showed an increase in chloride concentration, decrease in serumurea and osmolarity. In urine, anincrease in sodium and chloride concentrations and a decrease in calcium, creatinine and urea were observed. Enteral fluid therapy in continuous flow proved to beeasy to use and effective in maintaining volemia and concentration of electrolytes in buffalo calves
Palaeontological framework from Pirabas Formation (North Brazil) used as potential model for equatorial carbonate platform
The Pirabas Formation (early to middle Miocene) from the equatorial margin of North Brazil is characterized by a shallow-marine carbonate platform with high fossil diversity and abundant micro- and macrofossil remains. The Pirabas Formation represents a unique carbonate system along the Atlantic margin of South America that developed before the onset of the Amazon delta. We studied the palaeontology and lithofacies of outcrops of the uppermost Pirabas Formation and found that was deposited in a coastal marine environment with marginal lagoons under the influence of a tidal regime and tropical storms. The remains of calcareous algae, molluscs, crustaceans, echinoiderms, bryozoans, solitary corals, fish and marine mammals, together with foraminifera, ostracods and other marine microfossils, shaped a biogenic framework, that together with the post-depositional processes of dissolution of skeletal grains, is responsible for the mean packstone-floatstone porosity of 14.9%. The palaeontological framework and the petrophysical characterization of the carbonate rocks from the uppermost Pirabas Formation outcrop represent a baseline to interpret the entire Pirabas Formation in the subsurface stratigraphic sections (cores) of this important Neogene unit. Considering that carbonate rocks account for ~50% of oil and gas reservoirs around the world, this research provides a model for Neogene tropical carbonate deposits useful for carbonate petroliferous reservoirs in the Brazilian equatorial basins.publishe
- …