955 resultados para two-way active avoidance


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Tese para obter o grau de Mestre em Engenharia Electrónica e Telecomunicações

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With the help of a unique combination of density functional theory and computer simulations, we discover two possible scenarios, depending on concentration, for the hierarchical self-assembly of magnetic nanoparticles on cooling. We show that typically considered low temperature clusters, i.e. defect-free chains and rings, merge into more complex branched structures through only three types of defects: four-way X junctions, three-way Y junctions and two-way Z junctions. Our accurate calculations reveal the predominance of weakly magnetically responsive rings cross-linked by X defects at the lowest temperatures. We thus provide a strategy to fine-tune magnetic and thermodynamic responses of magnetic nanocolloids to be used in medical and microfluidics applications.

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This paper deals with the analysis of 10 batches of L.major-like and L.(V.) braziliensis antigens added or not of a proteases inhibitor evaluated by means of an IgG-ELISA on three consecutive days using positive standard sera from patients with diagnosis of American Leishmaniasis previously tested for the presence of IgG antibodies by means of ELISA. The statistical analysis showed that for L. (V.) braziliensis the PMSF-containing antigen did not show any difference among batches or days of testing; the L.(V.) braziliensis antigen without PMSF showed statistical significance for differences among batches and a two-way ANOVA showed significant differences between antigens. L.major-like antigen prepared with or without PMSF showed differences among batches; all 3 days of testing displayed differences for the PMSF antigen but only for days 1 and 2 for the antigen without inhibitor. A two-way ANOVA showed differences among batches of the antigens but not for antigens with and without the protein inhibitor. According to the statistical analysis the L.major-like antigen added or not of PMSF has shown that it is the choice antigen for mucocutaneous leishmaniasis serology.

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Neste artigo é analisada a construção do conhecimento matemático num jardim de infância do Porto, através do jogo; em particular, tratamos as formas geométricas e os diagramas de Carroll. Estes temas foram abordados, de uma forma integrada, numa atividade que também envolveu a expressão motora. Esta estratégia revelou-se uma boa forma de motivar as crianças do grupo para conteúdos complexos. Debruçamo-nos neste artigo sobre as fases de observação, planificação, ação e avaliação da atividade. Concluímos que os objetivos traçados foram ao encontro das necessidades e interesses das crianças e que a atividade contribuiu para o seu desenvolvimento integral e integrado.

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This paper has developed a model of a single forest owner operating with perfect foresight in a dynamic open-city environment that allows for switching between alternative competing land uses (forest and urban use) at some point in the future. The model also incorporates external values of an even-aged standing forest in addition to the value of timber when it is harvested. Timber is exploited based on a multiple rotation model a la Faustmann with clear-cut harvesting. In contrast to previous models, our alternative land use to forest land is endogenous. Within this framework, we study the problem of the private owner as well as that of the social planner, when choosing the time to harvest, the time to convert land and the intensity of development. We also examine the extent to which the two-way linkage between urban development and forest management practices (timber production and provision of forest amenities) contributes to economic efficiency and improvements in non-market forest benefits. Finally, we consider policy options available to a regulator seeking to achieve improvements in efficiency including anti-sprawl policies (impact fees and density controls) and forest policies such a yield tax. Numerical simulations illustrate our analytical results.

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Double Degree. A Work Project presented as part of the requirements for the Award of a Masters in Management from Nova School of Business and Economics and Maastricht University.

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Corporate social responsibility (CSR) literature has largely neglected consumers’ perceptions in the debate regarding the role of CSR in the aftermath of the financial crisis. In that context, this study aims to test the possibility that consumers’ perceptions of CSR level, firm reputation and brand trust, might depend on the type of industry sector of a firm, the level of fit of an initiative or both. By conducting a survey on Portuguese consumers and running a two-way analysis of variance, it suggests that solely the type of industry sector has an effect on consumer perception and that consumers are less tolerable of controversial industries.

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In order to investigate the out-of-plane behaviour of masonry infill walls, quasi-static testing was performed on a masonry infill walls built inside a reinforced concrete frame by means of an airbag system to apply the uniform out-of-plane load to each component of the infill. The main advantage of this testing setup is that the out-of-plane loading can be applied more uniformly in the walls, contrarily to point load configuration. The test was performed under displacement control by selecting the mid-point of the infill as control point. Input and output air in the airbag was controlled by using a software to apply a specific displacement in the control point of the infill wall. The effect of the distance between the reaction frame of the airbag and the masonry infill on the effective contact area was previously analysed. Four load cells were attached to the reaction frame to measure the out-of-plane force. The effective contact area of the airbag was calculated by dividing the load measured in load cells by the pressure inside the airbag. When the distance between the reaction walls and the masonry infill wall is smaller, the effective area is closer to the nominal area of the airbag. Deformation and crack patterns of the infill confirm the formation of arching mechanism and two-way bending of the masonry infill. Until collapse of the horizontal interface between infill and upper beam in RC frame, the infill bends in two directions but the failure of that interface which is known as weakest interface due to difficulties in filling the mortar between bricks of last row and upper beam results in the crack opening trough a well-defined path and the consequent collapse of the infill.

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Seismic investigations of typical south European masonry infilled frames were performed by testing two reduced scale specimens: one in the in-plane direction and another in the out-ofplane direction. Information about geometry and reinforcement scheme of those structures constructed in 1980s were obtained by [1]. The specimen to be tested in the in-plane direction was constructed as double leaf masonry while the specimen for testing in the out-of-plane direction is constructed with only its exterior leaf since the recent earthquakes have highlighted the vulnerability of the external leaf of the infills in out-of-plane direction [2]. The tests were performed by applying the pre-defined values of displacements in the in-plane and out-of-plane directions in the control points. For in-plane testing it was done by hydraulic actuator and for out-of-plane testing through the application of an airbag. Input and output air in the airbag was controlled by using a software to apply a specific displacement in the control point of the infill wall. Mid-point of the infill was assumed as a control point for outof- plane testing. Deformation and crack patterns of the infill confirm the formation of two-way arching mechanism of the masonry infill until collapse of the upper horizontal interface between infill and frame which is known as weakest interface due to difficulties in filling the mortar between bricks of last row and upper beam. This results in the crack opening through a welldefined path and the consequent collapse of the infill.

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FUNDAMENTO: O consumo de oxigênio de pico (VO2pico) pode ser definido como a maior taxa de consumo de oxigênio durante exercício exaustivo ou máximo. A avaliação da aptidão aeróbica pode ser expressa como relativa à massa corporal, mas esse procedimento pode não remover completamente as diferenças quando indivíduos pesados são avaliados. Assim, o procedimento com escala alométrica é uma estratégia atraente para comparar indivíduos com grandes diferenças em massa corporal. OBJETIVO: Investigar o VO2pico em indivíduos obesos e não-obesos usando o método de correção de massa corporal (convencional) e escala alométrica (método alométrico) e, como esses métodos são aplicados quando indivíduos de ambos os sexos se exercitam em uma esteira ergométrica. MÉTODOS: O VO2pico relativo ao peso corporal e pelo método alométrico foi comparado em 54 adolescentes obesos e 33 não-obesos (10 a 16 anos). Calorimetria indireta foi usada para avaliar o VO2pico durante um teste máximo. O expoente alométrico foi calculado levando-se em consideração a massa corporal individual. Então o VO2pico foi corrigido pelo expoente alométrico. As comparações foram realizadas usando-se two-way ANOVA para medidas repetidas (p<0,05). RESULTADOS: O VO2pico absoluto foi maior (p<0,05) em meninas obesas (2,80±0,69) quando comparadas às não-obesas (2,00±0,24), mas essa relação desapareceu nos indivíduos do sexo masculino (p>0,05). Entretanto, o VO2pico calculado pelo método convencional foi maior (p<0,05) entre indivíduos não-obesos para ambos os sexos (meninas: 41,45±3,85; meninos: 49,81±7,12) em comparação com os obesos (meninas: 32,11±4,48; meninos: 37,54±6,06). O VO2pico alométrico foi similar (p>0,05) entre os grupos. CONCLUSÃO: Indivíduos obesos apresentaram VO2pico mais baixo do que os não-obesos, quando avaliados pelo método convencional. Entretanto, quando o método da escala alométrica foi aplicado, as diferenças desapareceram.

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FUNDAMENTO: Estudos que relacionam exercícios físicos e saúde têm contribuído para a compreensão da influência de hábitos sedentários com a incidência de doenças cardiovasculares. OBJETIVO: Comparar o efeito de diferentes intensidades de exercício aeróbio sobre a capacidade funcional (VO2 pico) e a qualidade de vida de pacientes pós-infarto agudo do miocárdio. MÉTODOS: 87 homens (57,7 anos, ± 6,1) participaram deste estudo prospectivo, com 12 semanas de treinamento físico de alta intensidade (n=29), a 85% da frequência cardíaca máxima, de intensidade moderada (n=29), a 75% da frequência cardíaca máxima, ou no grupo controle (n=29), que recebeu acompanhamento clínico. O exercício aeróbio foi realizado cinco vezes por semana, 45 minutos por sessão, além de exercícios de resistência muscular e alongamentos. O VO2 pico foi mensurado com teste cardiopulmonar, e a qualidade de vida foi avaliada pelo questionário MacNew. RESULTADOS: A ANOVA two-way revelou aumento do VO2 pico significativo (p<0,05) no grupo de alta intensidade (29,9 ± 2,2 ml/kg.min para 41,6 ± 3,9 ml/kg.min) em relação ao grupo de moderada intensidade (32,0 ± 5,3 ml/kg.min para 37,1 ± 3,9 ml/kg.min). Além disso, ambos os grupos de exercício aumentaram significativamente em relação ao grupo controle (31,6 ± 3,9 para 29,2 ± 4,1). A qualidade de vida teve melhora significativa (p<0,05) no grupo de alta intensidade (5,66 para 6,80) e de moderada intensidade (5,38 para 6,72), mas não no grupo controle (5,30 para 5,15) CONCLUSÃO: Os exercícios de maior intensidade resultaram em maior aumento na capacidade funcional e na qualidade de vida em pacientes no pós-infarto do miocárdio.

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Fundamento: Estresse e etanol são ambos, independentemente, importantes fatores de risco cardiovascular. Objetivo: avaliar o risco cardiovascular do consumo de etanol e exposição ao estresse, isolados e em associação, em ratos machos adultos. Métodos: Os ratos foram separados em quatro grupos: controle, etanol (20% na água de beber durante seis semanas), estresse (imobilização 1h dia/5 dias por semana/ 6 semanas) e estresse/etanol. As curvas de concentração-resposta à noradrenalina - na ausência e na presença de ioimbina, L-NAME ou indometacina - ou fenilefrina foram determinadas em aortas torácicas com e sem endotélio. EC50 e resposta máxima (n = 8-12) foram comparadas através de ANOVA de dois fatores (two-way) / método de Bonferroni. Resultados: Estresse ou estresse em associação com o consumo de etanol aumentaram as respostas máximas de noradrenalina em aortas intactas. Essa hiper-reatividade foi eliminada pela remoção do endotélio, ou pela presença da indometacina ou ioimbina, mas não foi alterada pela presença de L-NAME. Enquanto isso, o consumo de etanol não alterou a reatividade à noradrenalina. As respostas da fenilefrina em aortas com e sem endotélio também permaneceram inalteradas independentemente do protocolo. Conclusão: O estresse crônico aumentou as respostas aórticas dos ratos à noradrenalina. Esse efeito é dependente do endotélio vascular e envolve a liberação de prostanóides vasoconstritores através da estimulação de α-2 adrenoceptores endoteliais. Além disso, o consumo crônico de etanol pareceu não influenciar as respostas de noradrenalina em aorta de rato, nem modificar o aumento de tais respostas observadas em consequência da exposição ao estresse.

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Background:Cardiovascular diseases affect people worldwide. Individuals with Down Syndrome (DS) have an up to sixteen-time greater risk of mortality from cardiovascular diseases.Objective:To evaluate the effects of aerobic and resistance exercises on blood pressure and hemodynamic variables of young individuals with DS.Methods:A total of 29 young individuals with DS participated in the study. They were divided into two groups: aerobic training (AT) (n = 14), and resistance training (TR) (n = 15). Their mean age was 15.7 ± 2.82 years. The training program lasted 12 weeks, and had a frequency of three times a week for AT and twice a week for RT. AT was performed in treadmill/ bicycle ergometer, at an intensity between 50%-70% of the HR reserve. RT comprised nine exercises with three sets of 12 repetition-maximum. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP) and hemodynamic variables were assessed beat-to-beat using the Finometer device before/after the training program. Descriptive analysis, the Shapiro-Wilk test to check the normality of data, and the two-way ANOVA for repeated measures were used to compare pre- and post-training variables. The Pearson’s correlation coefficient was calculated to correlate hemodynamic variables. The SPSS version 18.0 was used with the significance level set at p < 0.05.Results:After twelve weeks of aerobic and/or resistance training, significant reductions in variables SBP, DBP and MBP were observed.Conclusion:This study suggests a chronic hypotensive effect of moderate aerobic and resistance exercises on young individuals with DS.

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Abstract Background: Tobacco smoke exposure is an important risk factor for cardiac remodeling. Under this condition, inflammation, oxidative stress, energy metabolism abnormalities, apoptosis, and hypertrophy are present. Pentoxifylline has anti‑inflammatory, anti-apoptotic, anti-thrombotic and anti-proliferative properties. Objective: The present study tested the hypothesis that pentoxifylline would attenuate cardiac remodeling induced by smoking. Methods: Wistar rats were distributed in four groups: Control (C), Pentoxifylline (PX), Tobacco Smoke (TS), and PX-TS. After two months, echocardiography, invasive blood pressure measurement, biochemical, and histological studies were performed. The groups were compared by two-way ANOVA with a significance level of 5%. Results: TS increased left atrium diameter and area, which was attenuated by PX. In the isolated heart study, TS lowered the positive derivate (+dp/dt), and this was attenuated by PX. The antioxidants enzyme superoxide dismutase and glutathione peroxidase were decreased in the TS group; PX recovered these activities. TS increased lactate dehydrogenase (LDH) and decreased 3-hydroxyacyl Coenzyme A dehydrogenases (OH-DHA) and citrate synthase (CS). PX attenuated LDH, 3-OH-DHA and CS alterations in TS-PX group. TS increased IL-10, ICAM-1, and caspase-3. PX did not influence these variables. Conclusion: TS induced cardiac remodeling, associated with increased inflammation, oxidative stress, apoptosis, and changed energy metabolism. PX attenuated cardiac remodeling by reducing oxidative stress and improving cardiac bioenergetics, but did not act upon cardiac cytokines and apoptosis.

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The author investigated the distribution of lectin receptors on Trypanosoma cruzi blood forms collected from mice inoculated with, respectively, the drug-resistant and drug-sensitive strains VL-10 and CL, and treated with the two standard active nitroheterocyclic compounds nifurtimox and benznidazole used for treatment of human Chagas' disease. Blood trypomastigotes purified in Fycoll-Hypaque were incubated with fluorescein-labelled lectins Con A, WGA, EE, WFA, TPA and PNA and then microscopically examined. Neither qualitative or quantitative differences in the fluorescence intensity could be detected between parasites from VL-10 and CL strains submitted or not to treatment. The results suggest that both strains do not differ in their surface membrane carbohydrate moieties. Moreover, the rapid clearance of blood forms the drug-sensitive strain in animals treated with singlo doses of both compounds is not likely to depend on membrane alterations expressed by changes in the carbohydrate components. furthermore, resistance or sensitivity to drugs is not apparently related to carbohydrate distribution on T. cruzi blood forms.