805 research outputs found
Lorentz-CPT violation, radiative corrections and finite temperature
In this work we investigate the radiatively induced Chern-Simons-like terms
in four-dimensions at zero and finite temperature. We use the approach of
rationalizing the fermion propagator up to the leading order in the
CPT-violating coupling . In this approach, we have shown that although
the coefficient of Chern-Simons term can be found unambiguously in different
regularization schemes at zero or finite temperature, it remains undetermined.
We observe a correspondence among results obtained at finite and zero
temperature.Comment: To appear in JHEP, 10 pages, 1 eps figure, minor changes and
references adde
“Surfing in the cell” - an investigative game for teaching cytoskeleton concepts for undergraduate students
The educational role of games becomes evident as students are more active, able to take decisions, solve problems and react to the results of their own decisions. The educative board game Discovering the Cell is based on problem-solving learning. This game challenges students to collect, discuss and interpret clues in order to decipher a question. In this work we evaluated the game as a tool for teaching health sciences undergraduate students from Rio de Janeiro. In a questionnaire-based analysis, students demonstrated great acceptance for this strategy and the majority of them were able to solve the Case tested, as well as applying the learned content to answer a related question. Taken together, our results indicate the acceptance and suitability of the game as an alternative strategy to help teaching cell and molecular biology to undergraduate students
Effect of thyroparathyroidectomy on urinary acidification in diabetic rats
In previous studies we have shown stimulation of renal acid excretion in the proximal tubules of rats with diabetes of short duration, with no important alterations in glomerular hemodynamics; on the other hand, in thyroparathyroidectomized rats (TPTX model), a significant decrease in renal acid excretion, glomerular filtration rate (GFR) and renal plasma flow (RPF) was detected. Since important changes in the parathyroid hormone-vitamin D-Ca axis are observed in the diabetic state, the present study was undertaken to investigate the renal repercussions of thyroparathyroidectomy in rats previously made diabetic by streptozotocin (45 mg/kg). Four to 6 days after the induction of diabetes (DM), a group of rats were thyroparathyroidectomized (DM + TPTX). Renal functional parameters were evaluated by measuring the inulin and sodium para-aminohippurate clearance on the tenth day. The decrease in the GFR and RPF observed in TPTX was not reversed by diabetes since the same alterations were observed in DM + TPTX. Net acid (NA) excretion was unchanged in DM (6.19 ± 0.54), decreased in TPTX (3.76 ± 0.25) and returned to normal levels in DM + TPTX (5.54 ± 0.72) when compared to the control group (6.34 ± 0.14 µmol min-1 kg-1). The results suggest that PTH plays an important vasodilator role regarding glomerular hemodynamics, since in its absence the impairment in GFR and RPF was not reversed by the diabetic state. However, with respect to acid excretion, the presence of diabetes was able to overcome the negative stimulus represented by TPTX.Universidade Federal de São Paulo (UNIFESP)UNIFESPSciEL
Incidência da mancha foliar (Bipolaris incurvata) em três híbridos de coqueiro (cocos nucifera L.) em condições de campo.
Mais de 14.000 coqueiros estabelecidos em campo morreram, no período de 2000 a 2002, em decorrência da doença denominada mancha das folhas do coqueiro, causada por Bipolaris incurvata. O controle mais efetivo de doenças de plantas é a utilização de material geneticamente resistente. Este trabalho foi conduzido em plantio da Fazenda da Empresa Sococo, no município do Moju, PA, objetivando avaliar a incidência, em plantios estabelecidos de 1,5 ano, de três híbridos de coqueiro (PB 121, PB 123 e PB 132) que compõem a plantação comercial. O número de lesões em seis folíolos, três de cada lado, na parte central das folhas 1, 3 e 5, sentido basipetal, foi avaliado. Observou-se um número menor de lesões no híbrido PB 121, enquanto os híbridos PB 123 e PB 132 comportaram-se como mais suscetíveis à mancha foliar causada por B. incurvata, em condições de plantio definitivo
Coeficientes técnicos e avaliação econômica para o sistema de produção melhorado da pupunha para palmito no Acre.
A pupunha (Bactris gasipaes Kunth) é uma palmeira que apresenta várias alternativas de utilização: fruto cozido para consumo humano, fabricação de ração, farinha, óleo e palmito, sendo este último, o principal responsável pela expansão da área cultivada com a cultura no Acre (1 .004 ha), podendo a atividade tornar-se uma oportunidade de negócio para pequenos e médios produtores. O cultivo da pupunha para produção de palmito torna-se promissor devido à sua precocidade, rusticidade e elevado perfilhamento, além de permitir melhor controle da qualidade do produto final, quando comparado com o palmito de açaí (Euterpe oleracea) proveniente da exploração extrativa. Ressalta-se ainda o apelo ecológico de seu cultivo, uma vez que contribui para diminuir a pressão dessa atividade predatória. Pretende-se com este trabalho propor um sistema para produção de palmito que contemple as tecnologias de fácil assimilação pelos produtores e que sejam recomendadas pela pesquisa, relacionando as necessidades de materiais, equipamentos e serviços, passíveis de ser utilizados pelos pequenos produtores do Acre.bitstream/item/116573/1/12186.pd
Effects of dietary lipids on renal function of aged rats
Normal aging is accompanied by renal functional and morphological deterioration and dietetic manipulation has been used to delay this age-related decline. We examined the effects of chronic administration of diets containing 5% lipid-enriched diet (LD, w/w) on renal function of rats at different ages. Three types of LD were tested: canola oil, fish oil and butter. Mean systemic tail-cuff blood pressure and glycemia remained within the normal range whatever the age and the diet of the animals. Proteinuria began to rise from the 8th month in the groups ingesting LD, while in the control group it increased significantly (above 10 mg/24 h) only after the 10th month. With age, a significant and progressive decline in glomerular filtration rate (GFR) and renal plasma flow was observed in the LD groups but after 6 months of lipid supplementation, the decline in these parameters was more marked in the butter and fish oil groups. By the 18th month, the lowest GFR level was observed in the group ingesting the butter diet (2.93 ± 0.22 vs 5.01 ± 0.21 ml min-1 kg-1 in control, P<0.05). Net acid excretion, evaluated in 9- and 18-month-old rats, was stimulated in the fish oil group when compared both to control and to the other two LD groups. These results suggest that even low levels of LD in a chronic nutritional regimen can modify the age-related changes in renal function and that the impact of different types of lipid-supplemented diets on renal function depends on the kind of lipid present in the diet.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Disciplina de Fisiologia Renal e TermometabologiaUNIFESP, EPM, Disciplina de Fisiologia Renal e TermometabologiaSciEL
Assessment of squash seed vigor using computerized image analysis.
Este trabalho procurou verificar a eficiência do SVIS® (Seed Vigor Imaging System) para determinar o vigor de sementes de abóbora colhidas durante diferentes estádios de maturação. Utilizou-se a cultivar híbrida Jabras, proveniente do cruzamento entre Cucurbita maxima (linhagem feminina) e Cucurbita moschata (linhagem masculina)
Recuperação nutricional com farelo de arroz não modificou o balanço energético e os níveis de leptina e insulina
OBJECTIVE: To investigate the effect of nutritional recovery with rice bran on energy balance, leptin and insulin levels. METHODS: Weaned Wistar rats were fed on a 17% (Control - C) or 0.5% (Aproteic - A) protein diet for 12d. After this, rats were kept on a C diet (C) or recovered with control (Recovered Control - RC) or control plus recovered rice bran diet (Recovered Rice Bran - RRB). RESULTS: Despite the increased food intake, group A exhibited lower carcass fat associated to low serum leptin. RRB and RC groups showed lower carcass weight and energy intake and expenditure. Energy expenditure was positively associated with food intake and carcass weight. Negative correlations between HOMA-IR and energy expenditure and energy intake were observed. CONCLUSION: Nutritional recovery with rice bran did not modify energy balance, leptin and insulin levels.OBJETIVO: Investigar o efeito da recuperação nutricional com farelo de arroz sobre o balanço energético e níveis de leptina e insulina. MÉTODOS: Ratos Wistar recém-desmamados foram alimentados com 17% (Controle - C) ou 0,5% (Aproteico - A) de proteína (caseína) durante 12 dias. Em seguida, ratos permaneceram com dieta controle (C) ou foram recuperados com controle (Recuperados Controle - RC) ou controle mais 5% de farelo de arroz (Recuperados com Farelo de Arroz - RFA) durante 21 dias. RESULTADOS: Apesar de a ingestão alimentar ter sido maior em A, a gordura na carcaça foi reduzida, sendo associada com menor nível de leptina. Os grupos RFA e RC tiveram redução no peso da carcaça, no gasto e ingestão de energia. O gasto energético foi correlacionado com a ingestão de alimentos e o peso da carcaça fresco. Foi observada correlação negativa entre HOMA-IR com gasto energético e com ingestão de energia. CONCLUSÃO: A recuperação nutricional com farelo de arroz não modificou o balanço energético, nem os níveis de leptina e insulina.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de Mato Grosso Faculdade de NutriçãoUniversidade Federal de São Paulo (UNIFESP) Departamento de Fisiologia da NutriçãoUNIFESP, Depto. de Fisiologia da NutriçãoSciEL
On the coupling of the self-dual field to dynamical U(1) Matter and its dual theory
We consider an arbitrary U(1) charged matter non-minimally coupled to the
self-dual field in . The coupling includes a linear and a rather general
quadratic term in the self-dual field. By using both a Lagragian gauge
embedding and a master action approaches we derive the dual Maxwell
Chern-Simons type model and show the classical equivalence between the two
theories. At quantum level the master action approach in general requires the
addition of an awkward extra term to the Maxwell Chern-Simons type theory. Only
in the case of a linear coupling in the self-dual field the extra term can be
dropped and we are able to establish the quantum equivalence of gauge invariant
correlation functions in both theories.Comment: two citations and references corrected, 13 page
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