820 resultados para Modelo Big 6


Relevância:

30.00% 30.00%

Publicador:

Resumo:

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

Relevância:

30.00% 30.00%

Publicador:

Resumo:

O objetivo do trabalho foi elaborar um modelo para estimar as exigências de proteína bruta (PB) para poedeiras leves, usando o método fatorial. Para determinar as exigências de proteína bruta (PB) para manutenção foi utilizada a técnica do balanço de nitrogênio. A exigência de proteína bruta para o ganho de peso foi determinada em função do conteúdo de nitrogênio na carcaça e a eficiência de utilização do nitrogênio da dieta. A exigência de PB, para produção de ovos, foi determinada considerando o teor de PB determinado nos ovos e a eficiência de deposição do nitrogênio no ovo. A partir dos valores das exigências para manutenção, para o ganho e produção foi elaborada uma equação para predizer as exigências diárias de PB (g/ ave/ dia) para poedeiras: PB = 1,94. P0,75 + 0,48.G + 0,301.O, em que P = peso corporal (kg), G = ganho de peso diário (g/dia) e O = massa de ovos produzida (g/ave/dia).

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This work purposes the application of a methodology to optimize the implantation cost of an wind-solar hybrid system for oil pumping. The developed model is estimated the implantation cost of system through Multiple Linear Regression technique, on the basis of the previous knowledge of variables: necessary capacity of storage, total daily energy demand, wind power, module power and module number. These variables are gotten by means of sizing. The considered model not only can be applied to the oil pumping, but also for any other purposes of electric energy generation for conversion of solar, wind or solar-wind energy, that demand short powers. Parametric statistical T-student tests had been used to detect the significant difference in the average of total cost to being considered the diameter of the wind, F by Snedecor in the variance analysis to test if the coefficients of the considered model are significantly different of zero and test not-parametric statistical by Friedman, toverify if there is difference in the system cost, by being considered the photovoltaic module powers. In decision of hypothesis tests was considered a 5%-significant level. The configurations module powers showed significant differences in total cost of investment by considering an electrical motor of 3 HP. The configurations module powers showed significant differences in total cost of investment by considering an electrical motor of 5 HP only to wind speed of 4m/s and 6 m/s in wind of 3 m, 4m and 5 m of diameter. There was not significant difference in costs to diameters of winds of 3 m and 4m. The mathematical model and the computational program may be used to others applications which require electrical between 2.250 W and 3.750 W. A computational program was developed to assist the study of several configurations that optimizes the implantation cost of an wind-solar system through considered mathematical model

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The production of roof tiles in the state of Rio Grande do Norte accounts for around 60% of the total of ceramic pieces produced. There is a need for investment to improve quality and productivity, thereby promoting technological innovations. Accordingly, the aim of this study is to determine the effect of kaolin, potassium feldspar and quartz in two standard formulations, as well as the effect of sintering temperature on the technological properties of linear firing shrinkage, water absorption and bending rupture stress, by fitting the statistical model and using multiple linear regression to assess the relationship between technological properties and independent variables. The raw materials were characterized using the following techniques: X-ray fluorescence (XRF), X-ray diffraction (XRF), rational analysis (RA), differential thermal analysis (DTA) and granulometric analysis (GA). The test specimens were compacted by uniaxial pressure (25 MPa), dried in a stove at 110 ºC for 24 hours and sinterized at 850 ºC, 950 ºC and 1050 ºC and held isothermal for 30 minutes. The results obtained indicate that the addition of kaolin to two standard formulations (M and R) promoted a reduction in water absorption values and an increase in bending rupture stress values. The sintering temperatures for group M that resulted in the lowest linear firing shrinkage and water absorption values were 850 ºC and 950 ºC, respectively, and the highest bending rupture stress values were reached at a temperature of 950 ºC. In the case of group R, the sintering temperature that obtained the lowest water absorption and linear firing shrinkage values was 850 ºC, and the highest bending rupture stress values were attained at a temperature of 1050 ºC. This work explains the statistical approach used to fit the model that describes the relationship between the technological properties and percentage of kaolin, quartz and feldspar, as well as the models that enable predictions, provided that the lower and upper limits of the percentage of clay minerals, flux and quartz used in this study are respected. Statistica 6 software was used and results were obtained by stepwise forward regression

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The ferromagnetic and antiferromagnetic Ising model on a two dimensional inhomogeneous lattice characterized by two exchange constants (J1 and J2) is investigated. The lattice allows, in a continuous manner, the interpolation between the uniforme square (J2 = 0) and triangular (J2 = J1) lattices. By performing Monte Carlo simulation using the sequential Metropolis algorithm, we calculate the magnetization and the magnetic susceptibility on lattices of differents sizes. Applying the finite size scaling method through a data colappse, we obtained the critical temperatures as well as the critical exponents of the model for several values of the parameter α = J2 J1 in the [0, 1] range. The ferromagnetic case shows a linear increasing behavior of the critical temperature Tc for increasing values of α. Inwhich concerns the antiferromagnetic system, we observe a linear (decreasing) behavior of Tc, only for small values of α; in the range [0.6, 1], where frustrations effects are more pronunciated, the critical temperature Tc decays more quickly, possibly in a non-linear way, to the limiting value Tc = 0, cor-responding to the homogeneous fully frustrated antiferromagnetic triangular case.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The usual Ashkin-Teller (AT) model is obtained as a superposition of two Ising models coupled through a four-spin interaction term. In two dimension the AT model displays a line of fixed points along which the exponents vary continuously. On this line the model becomes soluble via a mapping onto the Baxter model. Such richness of multicritical behavior led Grest and Widom to introduce the N-color Ashkin-Teller model (N-AT). Those authors made an extensive analysis of the model thus introduced both in the isotropic as well as in the anisotropic cases by several analytical and computational methods. In the present work we define a more general version of the 3-color Ashkin-Teller model by introducing a 6-spin interaction term. We investigate the corresponding symmetry structure presented by our model in conjunction with an analysis of possible phase diagrams obtained by real space renormalization group techniques. The phase diagram are obtained at finite temperature in the region where the ferromagnetic behavior is predominant. Through the use of the transmissivities concepts we obtain the recursion relations in some periodical as well as aperiodic hierarchical lattices. In a first analysis we initially consider the two-color Ashkin-Teller model in order to obtain some results with could be used as a guide to our main purpose. In the anisotropic case the model was previously studied on the Wheatstone bridge by Claudionor Bezerra in his Master Degree dissertation. By using more appropriated computational resources we obtained isomorphic critical surfaces described in Bezerra's work but not properly identified. Besides, we also analyzed the isotropic version in an aperiodic hierarchical lattice, and we showed how the geometric fluctuations are affected by such aperiodicity and its consequences in the corresponding critical behavior. Those analysis were carried out by the use of appropriated definitions of transmissivities. Finally, we considered the modified 3-AT model with a 6-spin couplings. With the inclusion of such term the model becomes more attractive from the symmetry point of view. For some hierarchical lattices we derived general recursion relations in the anisotropic version of the model (3-AAT), from which case we can obtain the corresponding equations for the isotropic version (3-IAT). The 3-IAT was studied extensively in the whole region where the ferromagnetic couplings are dominant. The fixed points and the respective critical exponents were determined. By analyzing the attraction basins of such fixed points we were able to find the three-parameter phase diagram (temperature £ 4-spin coupling £ 6-spin coupling). We could identify fixed points corresponding to the universality class of Ising and 4- and 8-state Potts model. We also obtained a fixed point which seems to be a sort of reminiscence of a 6-state Potts fixed point as well as a possible indication of the existence of a Baxter line. Some unstable fixed points which do not belong to any aforementioned q-state Potts universality class was also found

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The circadian system consists of multiple oscillators organized hierarchically, with the suprachiasmatic nucleus (SCN) as the master oscillator to mammalians. There are lots of evidences that each SCN cell is an oscillator and that entrainment depends upon coupling degree between them. Knowledge of the mechanism of coupling between the SCN cells is essential for understanding entrainment and expression of circadian rhythms, and thus promote the development of new treatments for circadian rhythmicity disorders, which may cause various diseases. Some authors suggest that the dissociation model of circadian rhythm activity of rats under T22, period near the limit of synchronization, is a good model to induce internal desynchronization, and in this way, enhance knowledge about the coupling mechanism. So, in order to evaluate the pattern of the motor activity circadian rhythm of marmosets, Callithrix jacchus, in light-dark cycles at the lower limit of entrainment, two experiments were conducted: 1) 6 adult females were submitted to the LD symmetric cycles T21, T22 and T21.5 for 60, 35 and 48 days, respectively; 2) 4 male and 4 female adults were subjected to T21 for 24 days followed by 18 days of LL, and then back to T21 for 24 days followed by 14 days of LL. Vocalizations of all animals and motor activity of each one of them were continuously recorded throughout the experiments, but the vocalizations were recorded only in Experiment 1. Under the Ts shorter than 24 h, two simultaneous circadian components appeared in motor activity, one with the same period of LD cycle, named light-entrained component, and the other in free-running, named non-light-entrained component. Both components were displayed for all the animals in T21, five animals (83.3%) in T21.5 and two animals (33.3%) in T22. For vocalizations both components were observed under the three Ts. Due to the different characteristics of these components we suggest that dissociation is result of partial synchronization to the LD cycle, wherein at least one group oscillator is synchronized to the LD by relative coordination and masking processes, while at least another group of oscillators is in free-running, but also under the influence of masking by the LD. As the T21 h was the only cycle able to promote the emergence of both circadian components in circadian rhythms of all Callithrix jacchus, this was then considered the lower entrainment limit of LD cycle promoter of dissociation in circadian rhythmicity of this species, and then suggested as a non-human primate model for forced desynchronization

Relevância:

30.00% 30.00%

Publicador:

Resumo:

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

Relevância:

30.00% 30.00%

Publicador:

Resumo:

OBJETIVO: O presente estudo teve por objetivo caracterizar as alterações clínicas e laboratoriais do rato portador de Diabetes Mellitus induzido pela administração endovenosa de aloxana. MÉTODOS: Os animais foram distribuídos, por sorteio, em dois grupos experimentais: Grupo Controle Normal (G1), constituído de 25 animais sadios, e Grupo Diabético (G2), formado por 25 animais diabéticos graves, que foram avaliados em cinco momentos (1, 3, 6, 9 e 12 meses) de seguimento, tendo sido estudados os seguintes parâmetros: evolução clínica (peso, ingestão hídrica, ingestão alimentar e diurese) e exames bioquímicos (glicemia de jejum, glicose urinária, glicosúria, cetonúria, colesterol total, colesterol HDL, triglicérides e lipídios). RESULTADOS: A injeção de aloxana 2% na via endovenosa do rato acompanhou-se de um índice de mortalidade de 39%, tendo produzido diabetes grave também em 39% dos animais. O diabetes foi caracterizado por queda progressiva do peso corporal, elevação substancial da ingestão hídrica, ingestão alimentar e da diurese, com valores glicêmicos acima de 300 mg/dl, glicosúria 3+ e, eventualmente, cetonúria. O diabetes não altera o perfil de colesterol e lípides de ratos a longo prazo. CONCLUSÃO: Nossos estudos revelam que a aloxana produz, no rato, alterações clínicas e laboratoriais características de diabetes grave, as quais possibilitam estudos a longo prazo do diabetes.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This study analysed the creation of businesses by entrepreneur women in the Currais Novos city, looking for verifying if they used making decision processes aligned to the Effectuation logic throughout the creation of their companies. To this, was accomplished a multiple cases and exploratory study, whit a qualitative approach of analyse, using the thematic life history technique that match accounts and semi-structured interview route, being accomplished like a long interview, where the researcher interact with the informer continuously. The semi-structured interview route was created by the adaptation of the interview route used by Tasic (2007). The present study appealed to a intentional selection of individuals in function of their importance in relation to the boarded theme. This means that the individuals were chosen in function of their social and theoretical representatively inside the considered situation. The participant individuals of this research were five entrepreneur women that act in the Currais Novos city, owners of five different companies. To the data treatment and analyse, was chosen the content analyse technique. This study worked with a priori theoretical categories. The categories of analyse in this study was obtained with base in the Effectuation approach (SARASVATHY, 2001a, 2001b, 2008), that is an alternative model of making decision to the classic model based in the causality principle. These categories are Clarity of Initial Aims , Tolerance to the Lost and Initials Investments , Control of Resources ( who I am , what I know and who I know ) and Promoting Over Contingencies . As result, the entrepreneur women researched, in a general way, hadn t clear initial aims at the companies creation moment, hadn t aversion to the risk to lose the time and the money that they were investing in the company in formation, they highlighted the products and services identity that offered with a strong link with Seridó region, they had experience in the field of activity in which they decided to open their companies, had the commitment of partners in the beginning of the business and they knew to transform the initial difficulties in opportunities. By the end, this study conclude that the entrepreneur women studied used, in a big part, making decision processes aligned to the Effectuation logic throughout the creation of their companies

Relevância:

30.00% 30.00%

Publicador:

Resumo:

CONTEXTO: A aplicação de uma estratégia baseada em um modelo clínico associado ao mapeamento dúplex (MD) pode permitir um diagnóstico da trombose venosa profunda (TVP) mais seguro, eficaz e custo-efetivo. OBJETIVO: Testar o modelo clínico de Wells et al. associado ao MD e verificar a ocorrência de TVP nos pacientes categorizados quanto à probabilidade de apresentar a doença, e determinar se, a partir dos resultados obtidos, seria possível reduzir o número de exames seriados com o MD. MÉTODOS: Os pacientes com suspeita clínica de TVP foram categorizados quanto à apresentação de TVP em baixa, moderada e alta probabilidade (BP, MP, AP) e, em seguida, submetidos ao MD. Pacientes com MD negativo repetiram o exame em 24-48 horas e em 7 dias. Pacientes com exame positivo para TVP foram tratados. Todos os pacientes sem TVP foram convocados para reavaliação clínica em 3 meses. RESULTADOS: A ocorrência de TVP entre os 489 pacientes avaliados foi de 39,1% (191), sendo 35,6% identificados no exame inicial e 3,5% no exame seriado. Os índices de pacientes que apresentaram TVP foram de 6,1% no grupo de BP, 26,9% no grupo de MP e 79,5% no grupo de AP. No exame seriado, o percentual de TVP foi de 2,4, 7,8 e 15,1% nos grupos BP, MP e AP, respectivamente. Dos pacientes com MD negativo, 62,4% compareceram após 3 meses, e piora dos sintomas foi apresentada por apenas um paciente. Neste, o MD mostrou TVP de veia poplítea. CONCLUSÃO: Os resultados obtidos sugerem que, para os pacientes com BP para TVP e MD negativo, seria possível prescindir do exame seriado, devido à baixa ocorrência de TVP neste grupo, tornando, assim, a abordagem diagnóstica mais simples.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Fucans seaweed Lobophora variegata estructures are known for their chemical and biological properties. In this study, we analyzed, the action of fucans L. variegata and the fractions purified with acetone in Zymosan-induced arthritis. After differential fractionation with acetone, six fractions were obtained and named F0.3, F0.5, F0.8, F1, F1.5 and F2. The results showed that the fraction F1 showed high yield (51.9%) and was chosen for studies of antioxidant activity and induced arthritis. Nuclear magnetic resonance (NMR) of 13C showed signals at 103.3 and 15.78 ppm that are assigned to links β13 galactose and of the C6 methyl fucose, respectively. The infrared (IR) showed absorbance at 1238 and 850 cm-1 which are attributed to sulfate. The fraction F1 showed antioxidant activities in vitro. For analysis of inflammatory parameters chosen the polysaccharide was administered in different doses (25, 50 and 75 mg / kg ip, per body weight) and diclofenac sodium (5 mg / kg ip) and L-NAME (25 mg / kg ip) in groups of animals (n = 6). After 6 h, were analyzed for cellular influx and levels of nitrite. In experiment five days, were made analysis of swelling and serum TNF-α. Histopathological analysis were performed for confirmation of results. The fraction F1 (25, 50 and 75 mg / kg ip) reduced the cellular influx (52.1 to 96.7%) and nitric oxide levels (27.2 - 39%) compared to control group. The reduction of edema (63.4 - 100%) and serum TNF-α (p <0.001) were observed when the polysaccharide F1 administered at a dose (50 mg / kg) These results suggest that these heterofucanas of Lobophora variegata have besides the activity antioxidant and potential anti-inflammatory activity in arthritis induced by zymosan

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Objetivo: desenvolver o modelo experimental de hipertensão tipo Goldblatt I (1 rim - 1 clipe), em ratas, para estudar a interação entre hipertensão e prenhez. Métodos: o experimento foi dividido em 5 períodos: adaptação (2 semanas), cirúrgico (1 semana), desenvolvimento da hipertensão (6 semanas), acasalamento e estabilização da pressão arterial (6 semanas) e prenhez (3 semanas). Foram utilizadas 82 ratas virgens da raça Wistar, pesando entre 180-240 gramas e com idade entre 3 e 4 meses. As ratas foram sorteadas para compor os 4 grupos experimentais (controle, manipulação, nefrectomia e hipertensão) e estudadas em 15 momentos distintos (M1 a M15). A hipertensão foi induzida experimentalmente pela técnica de Goldblatt I (1 rim, 1 clipe), que consiste na constrição da artéria renal esquerda e nefrectomia contralateral. Posteriormente, foram realizadas medidas periódicas da pressão arterial pelo método da pletismografia de cauda (PAC). Resultados: os animais sem tratamento cirúrgico (controle) e com manipulação não apresentaram alterações na PAC durante o experimento. A nefrectomia determinou discreta elevação da PAC. Nos grupos de ratas prenhes, observou-se tendência a discreta diminuição da PAC, que se acentuou no final da prenhez. Conclusões: o modelo experimental foi adequado para o objetivo de nosso estudo, pois permitiu a obtenção de animais hipertensos.