Stochastic exponential stability of singular linear systems with Markov jump parameters

This paper deals with exponential stability of discrete-time singular systems with Markov jump parameters. We propose a set of coupled generalized Lyapunov equations (CGLE) that provides sufficient conditions to check this property for this class of systems. A method for solving the obtained CGLE is also presented, based on iterations of standard singular Lyapunov equations. We present also a numerical example to illustrate the effectiveness of the approach we are proposing.

Involvement of central cholinergic mechanisms on sodium intake induced by gabaergic activation of the lateral parabrachial nucleus

Bilateral injections of the GABAA agonist muscimol into the lateral parabrachial nucleus (LPBN) disrupt satiety and induce strong ingestion of water and 0.3M NaCl in fluid-replete rats by mechanisms not completely clear. In the present study, we investigated the effects of the blockade of central muscarinic cholinergic receptors with atropine injected intracerebroventricularly (i.c.v.) on 0.3M NaCl and water intake induced by muscimol injections into the LPBN in fluid-replete rats. Male Holtzman rats with stainless steel cannulas implanted bilaterally into the LPBN and unilaterally into the lateral ventricle (LV) were used. Bilateral injections of muscimol (0.5nmol/0.2μL) into the LPBN induced 0.3M NaCl (32.2±9.9mL/4h, vs. saline: 0.4±0.2mL/4h) and water intake (11.4±4.4mL/4h, vs. saline: 0.8±0.4mL/4h) in fluid-replete rats previously treated with i.c.v. injection of saline. The previous i.c.v. injection of atropine (20nmol/1μL) reduced the effects of LPBN-muscimol on 0.3M NaCl (13.5±5.0mL/4h) and water intake (2.9±1.6mL/4h). The i.c.v. injection of atropine did not affect 0.3M NaCl (26.8±6.2mL/2h, vs. saline i.c.v.: 36.5±9.8mL/2h) or water intake (14.4±2.5mL/2h, vs. saline i.c.v.: 15.6±4.8mL/2h) in rats treated with furosemide+captopril subcutaneously combined with bilateral injections of moxonidine (α2-adrenoceptor/imidazoline agonist, 0.5nmol/0.2μL) into the LPBN, suggesting that the effect of atropine was not due to non-specific inhibition of ingestive behaviors. The results show that active central cholinergic mechanisms are necessary for the hypertonic NaCl and water intake induced by the blockade of the inhibitory mechanisms with injections of muscimol into the LPBN in fluid-replete rats. The suggestion is that in fluid-replete rats the action of LPBN mechanisms inhibits facilitatory signals produced by the activity of central cholinergic mechanisms to maintain satiety. © 2012 Elsevier B.V.

The relationship between visceral fat thickness and bone mineral density in sedentary obese children and adolescents

Background: Among adults, obesity has been positively related to bone mineral density. However, recent findings have pointed out that abdominal obesity could be negatively related to bone density. The above mentioned relationship is not clear among pediatric populations. Therefore, this cross-sectional study analyzed the relationship between thickness of abdominal adipose tissue and bone mineral variables in sedentary obese children and adolescents.Methods: One hundred and seventy five obese children and adolescents (83 male and 92 female) with ages ranging from 6 to 16 years-old were analyzed. Bone mineral content and density were estimated by dual-energy X-ray absorptiometry and ultrasound equipment which estimated the thickness of the abdominal adipose tissue. Pubertal stage was self-reported by the participants.Results: The mean age was 11.1 (SD = 2.6). Thickness of the abdominal adipose tissue was negatively related to bone mineral density (r = -0.17 [r95%CI: -0.03;-0.32]), independent of gender, pubertal stage and other confounders (β = -0.134 ± 0.042 [β95%CI: -0.217; -0.050]).Conclusions: In sedentary obese children and adolescents abdominal obesity is negatively related to bone mineral density, suggesting a potential link between abdominal obesity and osteoporosis. © 2013 Júnior et al.; licensee BioMed Central Ltd.

Effect of the bone marrow cell transplantation on elevated plus-maze performance in hippocampal-injured mice

Several reports have shown that the hippocampus plays an important role in different aspects of the emotional control. There is evidence that lesions in this structure cause behavioral disinhibition, with reduction of reactions expressing fear and anxiety. Thus, to portray the aptitude of cell therapy to abrogate injuries of hippocampal tissue, we examined the behavioral effects of bone marrow mononuclear cells (BMMCs) transplantation on C57BL/6 mice that had the hippocampus damaged by electrolytic lesion. For this purpose, mice received, seven days after bilateral electrolytic lesion in the dorsal hippocampus, culture medium or BMMCs expressing the enhanced green fluorescent protein (EGFP) transgene. One week after transplantation, animals were tested in the elevated plus-maze (EPM). On the whole, three assessment sessions in the EPM were carried out, with seven days separating each trial. Thirty-five days after the induction of injury, mice were sacrificed and their brains removed for immunohistochemistry. The behavioral evaluation showed that the hippocampal lesion caused disinhibition, an effect which was slightly lessened, from the second EPM test, in transplanted subjects. On the other hand, immunohistochemical data revealed an insignificant presence of EGFP+ cells inside the brains of injured mice. In view of such scenario, we hypothesized that the subtle rehabilitation of the altered behavior might be a result from a paracrine effect from the transplanted cells. This might have been caused by the release of bioactive factors capable of boosting endogenous recuperative mechanisms for a partial regaining of the hippocampal functions. © 2013 Elsevier B.V.

Açai (Euterpe oleracea Mart.) feeding attenuates dimethylhydrazine-induced rat colon carcinogenesis

This study investigated the protective effect of spray-dried açaí powder (AP) intake on colon carcinogenesis induced by 1,2-dimethylhydrazine (DMH) in male Wistar rats. After 4. weeks of DMH administrations, the groups were fed with standard diet, a diet containing 2.5% or 5.0% AP or a diet containing 0.2% N-acetylcysteine (NAC) for 10. weeks, using aberrant crypt foci (ACF) as the endpoint. Additionally, two groups were fed with standard diet or a diet containing 5.0% AP for 20. weeks, using colon tumors as the endpoint. In ACF assay, a reduction in the number of aberrant crypts (ACs) and ACF (1-3 AC) were observed in the groups fed with 5.0% AP (37% AC and 47% ACF inhibition, p=. 0.036) and 0.2% NAC (39% AC and 41% ACF inhibition, p=. 0.042). In tumor assay, a reduction in the number of invasive tumors (p<. 0.005) and tumor multiplicity (p=. 0.001) was observed in the group fed with 5.0% AP. Also, a reduction in tumor Ki-67 cell proliferation (p=. 0.003) and net growth index (p=. 0.001) was observed in the group fed with 5.0% AP. Therefore the findings of this study indicate that AP feeding may reduce the development of chemically-induced rat colon carcinogenesis. © 2013 Elsevier Ltd.

Efeito do exercício físico de intensidade moderada sobre fatores de risco cardiovascular e marcadores inflamatórios de mulheres obesas no período pós-menpausa

Pós-graduação em Fisioterapia - FCT

Emprego de membrana de celulose microfibrilar na ceratoplastia lamelar em coelhos (O. cuniculus, Linnaeus, 1758): aspectos clínicos, morfológicos e imunoistoquimicos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Qualidade de cavacos produzidos em sistemas florestais de curta rotação de eucalipto para fins energéticos

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Adsorção de íons Cu(II) sobre superfícies de sílicas gel modificadas com 4-amino-2-mercaptopirimidina e com 2-mercaptopirimidina

Pós-graduação em Ciência dos Materiais - FEIS

Efeito protetor do açaí (Euterpeoleracea Martius) na promoção da carcinogênese de cólon em ratos Wistar

Pós-graduação em Patologia - FMB

Otimização de procedimentos para a determinação de maganês em amplo intervalo de concentração por espectrometria de absorção atômica em chama

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento de métodos limpos para screening e determinação de sulfonamidas em matrizes diversas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Fatores que interferem na produção de embriões bovinos mediante aspeiração folicular e fecundação in vitro

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Biochemical polymorphisms and genetic relationships between Brazilian and foreign breeds of pigs reared in Brazil

Foi investigada a variabilidade genética de 14 sistemas protéicos codificados por 15 locos estruturais em amostras de sangue de suínos das raças Piau e Caruncho. Os resultados foram comparados com àqueles obtidos previamente para amostras de Landrace, Large White, Duroc e Mouro. O grau de variabilidade genética obtida para Piau (He=0,114) foi similar àquelas estimadas para outras raças criadas no Brasil (Landrace, He=0,116; Large White, He=0,119; Duroc, 0,095; Mouro, He= 0,130). Caruncho apresentou a menor variabilidade (He= 0,056). A partir das freqüências gênicas dos locos polimórficos, foi calculada a eficiência de cada sistema para testes de paternidade e as probabilidades combinadas de exclusão de paternidade foram estimadas em 58% para Piau e 36% para Caruncho. Análises das distâncias genéticas revelaram que a raça mais próxima da Piau foi a Landrace (D=0,042). Caruncho apresentou as maiores divergências em relação a todas as raças comparadas, que variaram de 0,107 (com Landrace) a 0,176 (com Duroc). A árvore construída através de UPGMA e Distância de Rogers mostrou uma topologia na qual Piau e Mouro se uniram as raças Européias (Landrace e Large White), e Caruncho está separado de todas as demais raças. Os resultados das análises das amostras de Caruncho devem ser interpretados com cautela, uma vez que o número de animais estudados foi pequeno.

Variabilidade sazonal da condutância estomática em um ecossistema de manguezal amazônico e suas relações com variáveis meteorológicas

No presente trabalho foram estudadas as variações da condutância estomática (g_s) para o período chuvoso (março) e seco (agosto) do ano de 2003, e suas relações de dependência com algumas variáveis meteorológicas medidas em um ecossistema de manguezal amazônico. As informações utilizadas foram do projeto ECOBIOMA, parte integrante do Experimento de Grande Escala da Biosfera-Atmosfera da Amazônia (LBA). A g_s acompanha a tendência de variação do balanço de radiação, atingindo valores máximos durante o dia e mínimos durante a noite. A condutância apresentou maiores flutuações no período chuvoso, com valor médio de g_s = 0,015 m s^-1, porém com magnitudes inferiores as do período seco. Durante a época seca apresentou um valor médio de g_s = 0,027 m s^-1, com menor amplitude, variando de 0,010 < g_s < 0,042 m s^-1. As variáveis meteorológicas utilizadas para o estabelecimento de relações de dependência com a variabilidade diária de g_s foram déficit de umidade específica (δq), déficit de pressão de vapor (DPV), saldo de radiação (Rn) e velocidade do vento (Vv). O DPV apresentou as melhores correlações com a g_s sendo o R² = 0,99 em ambos os períodos. Apesar de também ser importante nas trocas gasosas entre a vegetação e a atmosfera, a Vv apresentou a menor influência na variação média da g_s, com um R² = 0,44 para época chuvosa e R² =0,51 para o período seco.