953 resultados para Partículas eletricamente sensíveis


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The standard kinetic theory for a nonrelativistic diluted gas is generalized in the spirit of the nonextensive statistic distribution introduced by Tsallis. The new formalism depends on an arbitrary q parameter measuring the degree of nonextensivity. In the limit q = 1, the extensive Maxwell-Boltzmann theory is recovered. Starting from a purely kinetic deduction of the velocity q-distribution function, the Boltzmann H-teorem is generalized for including the possibility of nonextensive out of equilibrium effects. Based on this investigation, it is proved that Tsallis' distribution is the necessary and sufficient condition defining a thermodynamic equilibrium state in the nonextensive context. This result follows naturally from the generalized transport equation and also from the extended H-theorem. Two physical applications of the nonextensive effects have been considered. Closed analytic expressions were obtained for the Doppler broadening of spectral lines from an excited gas, as well as, for the dispersion relations describing the eletrostatic oscillations in a diluted electronic plasma. In the later case, a comparison with the experimental results strongly suggests a Tsallis distribution with the q parameter smaller than unity. A complementary study is related to the thermodynamic behavior of a relativistic imperfect simple fluid. Using nonequilibrium thermodynamics, we show how the basic primary variables, namely: the energy momentum tensor, the particle and entropy fluxes depend on the several dissipative processes present in the fluid. The temperature variation law for this moving imperfect fluid is also obtained, and the Eckart and Landau-Lifshitz formulations are recovered as particular cases

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In this work we obtain the cosmological solutions and investigate the thermodynamics of matter creation in two diferent contexts. In the first we propose a cosmological model with a time varying speed of light c. We consider two diferent time dependence of c for a at Friedmann-Robertson- Walker (FRW) universe. We write the energy conservation law arising from Einstein equations and study how particles are created as c decreases with cosmic epoch. The variation of c is coupled to a cosmological Λ term and both singular and non-singular solutions are possible. We calculate the "adiabatic" particle creation rate and the total number of particles as a function of time and find the constrains imposed by the second law of thermodynamics upon the models. In the second scenario, we study the nonlinearity of the electrodynamics as a source of matter creation in the cosmological models with at FRW geometry. We write the energy conservation law arising from Einstein field equations with cosmological term Λ, solve the field equations and study how particles are created as the magnetic field B changes with cosmic epoch. We obtain solutions for the adiabatic particle creation rate, the total number of particles and the scale factor as a function of time in three cases: Λ = 0, Λ = constant and Λ α H2 (cosmological term proportional to the Hubble parameter). In all cases, the second law of thermodynamics demands that the universe is not contracting (H ≥ 0). The first two solutions are non-singular and exhibit in ationary periods. The third case studied allows an always in ationary universe for a suficiently large cosmological term

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

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The study of sunspots consistently contributed to a better understanding of magnetic phenomena of the Sun, as its activity. It was found with the dynamics of sunspots that the Sun has a rotation period of twenty-seven days around your axis. With the help of Project Sun-As-A-Star that solar spectra obtained for more than thirty years we observed oscillations of both the depth of the spectral line and its equivalent width, and analysis of the return information about the characteristics of solar magnetism. It also aims to find patterns of solar magnetic activity cycle and the average period of rotation of the Sun will indicate the spectral lines that are sensitive to magnetic activity and which are not. Sensitive lines how Ti II 5381.0 Å stands as the best indicator of the solar rotation period and also shows different periods of rotation cycles of minimum and maximum magnetic activity. It is the first time we observe clearly distinct rotation periods in the different cycles. The analysis also shows that Ca II 8542.1 Å and HI 6562.0 Å indicate the cycle of magnetic activity of eleven years. Some spectral lines no indicated connection with solar activity, this result can help us search for programs planets using spectroscopic models. Data analysis was performed using the Lomb-Scargle method that makes the time series analysis for unequally spaced data. Observe different rotation periods in the cycles of magnetic activity accounts for a discussion has been debated for many decades. We verified that spectroscopy can also specify the period of stellar rotation, thus being able to generalize the method to other stars

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We address the generalization of thermodynamic quantity q-deformed by q-algebra that describes a general algebra for bosons and fermions . The motivation for our study stems from an interest to strengthen our initial ideas, and a possible experimental application. On our journey, we met a generalization of the recently proposed formalism of the q-calculus, which is the application of a generalized sequence described by two parameters deformation positive real independent and q1 and q2, known for Fibonacci oscillators . We apply the wellknown problem of Landau diamagnetism immersed in a space D-dimensional, which still generates good discussions by its nature, and dependence with the number of dimensions D, enables us future extend its application to systems extra-dimensional, such as Modern Cosmology, Particle Physics and String Theory. We compare our results with some experimentally obtained performing major equity. We also use the formalism of the oscillators to Einstein and Debye solid, strengthening the interpretation of the q-deformation acting as a factor of disturbance or impurity in a given system, modifying the properties of the same. Our results show that the insertion of two parameters of disorder, allowed a wider range of adjustment , i.e., enabling change only the desired property, e.g., the thermal conductivity of a same element without the waste essence

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Conselho Nacional de Desenvolvimento Científico e Tecnológico

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The gray mold, causal organism Amphobotrys ricini, is one of the major diseases of castor bean. Difficulties in managing plant disease arises form the limited understanding of the genetic structure of A. ricini, their complexity and variability make it difficult to control. Genetic structure can be used to infer the relative impact of different forces that influence the evolution of pathogen populations, that allow to predict the potencial for pathogen populations to envolve in agricultural ecosystems. Growers protect their crop by applying fungicides, but there aren t fungicides to provide significant control of gray mold of castor bean. The objectives of this work were use RAPD to determine the genetic structure of A. ricini subpopulations in Paraíba and assay the sensitivity of A. ricini isolates to azoxystrobin and carbendazim. To determine the genetic structure of A. ricini subpopulations in Paraíba, 23 isolates were colleted from two different geographic location (subpopulation). These isolates were analysed by RAPD using 22 random decamer primers, purchased from OPERON, produced a total of 80 markers polimorphics. The resulting matrixes were analysed using PopGene version 1.32. Sensitivity to azoxystrobin and carbendazim of 30 isolates, colleted form Paraíba and Alagoas, was estimated based on spore germination and colony growth inhibition. The stock solutions were added toV8 medium after sterilization to produce final concentrations of 0, 0.01, 0.1, 1, 10, and 100 µg/ml of carbendazim and 0, 0.001, 0.01, 0.1, 1, and 10 µg/ml of azoxystrobin. All statistical analyses were performed using SAS to estimate the dose that inhibited fungal growth by 50% (ED50 values). The genetic diversity within subpopulations (Hs=0,271) accounted for 92% of the total genetic diversity (Ht=0,293), while genetic diversity between subpopulations (Gst = 0,075) represented only 7,5%. The estimated number of migrants per generation (NM ) was 6,15. Nei s average gene identity across 80 RAPD loci was 0,9468. Individual ED50 values, for the 30 isolates screened for their sensitivity to azoxystrobin, ranged From a maximum of 0,168 µg/ml to a minimum of 0,0036 µg/ml. The ED50 values for carbendazim varied within the range of 0,026 to 0,316 µg/ml

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The present study has the purpose of catching the significances of smoking in the social dinamics based on the Theory of Social Representations. It was developed among adults with ages from 20 to 59 years, low social and economic conditions, at Natal RN, Brazil. The Free-words Association Test was applied as the instrument of data collection and a semi-structured interview with the smokers and non-smokers, besides a structured interview with smokers, non-smokers and ex-smokers. All data was analyzed by the descriptive statistics using the Analysis of Content Technique of the thematic kind and by the softwares ALCESTE and EVOC 2000. Elaborations about smoking were marked by social, cultural and historical dimension, however they showed sensibility to changes and revealed positive and negative aspects of the habit. The analysis of the semi-structured interviews showed the following categories and under-categories respectively: Initiation of the habit (Friends and Family and Appreciation and Beauty); Psychosocial Implications of smoking (Personal relationship, Work and Financial); Behavior when facing smoking (Positive, Negative and Neutral); Smoking Effects (Smokers´ health and the other people health); Description about oral diseases ( Bad breath, Oral cancer and Dental problems); Smoking treatment (Physician and psychological, Supernatural and Difficulties). ALCESTE analysis presented 4 classes: Ambivalence between pleasure and get ill, Smoking as a trouble and danger to society, Social discrimination of smokers and Mouth as a place of reaffirmation of the discrimination. Those helped us to understand the psychosocial repercussion of the habit. On the social representation structure we identified as a probable central nucleus of the smoker group the categories Pleasure and Bad to the health and as peripheral elements Alcoholic Drink, Financial damage and Nervousness. For the non-smoker group the category Bad to the health comes first and Stop Smoking comes as a peripheral element. Finally, we hope that the knowledge of these representations can contribute to plan and/or to rethink over the professional practices and public policies related to smoking. Besides that, for an amplified comprehension of the study object the discussions over the identified representations should be deepen and amplified to other population and social groups

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The aim of this study was to assess the impact of the Family Health Program (FHP) on a number of oral health indicators in the population of Natal, Brazil. The study is characterized as a quasi-random community intervention trial. The intervention is represented by the implementation of an Oral Health Team (OHT) in the FHP prior to the study. A total of 15 sectors covered by the FHP with OHT were randomly drawn and paired with another 15 sectors, based on socioeconomic criteria, not covered by the teams. A few sectors were lost over the course of the study, resulting in a final number of 22 sectors, 11 covered and 11 not covered. We divided the non-covered areas into two conditions, one in which we considered areas that had some type of assistance program such as the Community Agents Program (CAP), FHP without OHT, BHU (Basic Health Unit) or no assistance, and the other, in which we considered areas that had only BHU or no assistance. Community Health Agents (CHAs) and Dental Office Assistants (DOAs) applied a questionnaire-interview to the most qualified individual of the household and the data obtained per household were transformed into the individual data of 7186 persons. The results show no statistical difference between the oral health outcomes analyzed in the areas covered by OHT in the FHP and in non-covered areas that have some type of assistance program, with a number of indicators showing better conditions in the non-covered areas. When we considered the association between covered and non-covered areas under the second condition, we found a statistical difference in the coverage indicators. Better conditions were found in covered areas for indicators such as I have not been to the dentist in the last year with p < 0.001 and OR of 1.64 and I had no access to dental care with p < 0.001 and OR of 2.22. However, the results show no impact of FHP with OHT on preventive action indicators under both non-covered conditions. This can be clearly seen when we analyze the toothache variable, which showed no significant difference between covered and non-covered areas. This variable is one of the most sensitive when assessing oral health programs, with p of 0.430 under condition 1 and p of 0.038 under condition 2, with CI = 0.70-0.90. In the analysis of health indicators in children where the proportion of deaths in children under age 1, the rate of hospitalization for ARI (Acute Respiratory Infections) in those under age 5 and the proportion of individuals born underweight were considered, a better condition was found in all the outcomes for areas with FHP. Therefore, we can conclude that oral health in the FHP has little effect on oral health indicators, even though the strategy improves the general health conditions of the population, as, for example child health

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

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Os materiais cerâmicos são atualmente cada vez utilizados como opção na engenharia mundial. Por se tratar de materiais com alta resistência mecânica, possuem muitas aplicações em diversas áreas, como por exemplo a de mancais, a automotiva (sensores, isoladores, catalisadores, pistões, válvulas, revestimentos), a de implantes biocompatíveis (dentário, substituição óssea, válvulas cardíacas), a de produtos sujeitos ao desgaste (guias), a de refratários (revestimento de equipamento bélico, componentes de fornos), a eletrônica, e outras. Nos processos de fabricação da cerâmica há uma gama de fatores que contribuem para as características do produto final. Devido a isso, muitos pesquisadores têm trabalhado no estudo da influência de determinados defeitos e técnicas de produção de cerâmicas nas características do produto final. Este trabalho tem como objetivo fazer uma revisão bibliográfica de recentes artigos que analisam a influência de fatores como velocidade de queima, surgimento de trincas, porosidade, fases cristalinas, e tamanho de partículas, nas propriedades mecânicas finais das cerâmicas. Pode-se concluir que é possível aperfeiçoar o processo de fabricação da cerâmica a fim de promover as melhores propriedades mecânicas possíveis, conhecendo-se fatores prejudiciais e métodos adequados para se obter o melhor produto final.

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The light, besides the vision stimuli, controls other process completely independent of image formation, such as the synchronization of the organismic circadian rhythms to the enviromental light/dark cycle. In mammals, this adjust occurs through the retinohypothalamic tract, a direct retinal projection to the suprachiasmatic nucleus, considered to be the major circadian pacemaker. Early studies have identified only the suprachiasmatic nucleus as a retinal target in the hypothalamus. However, using more sensitive neuroanatomic tracers, other retinorecipient hypothalamic regions outside to suprachiasmatic nucleus were pointed in a great number of mammalian species. In this study, the retinohypothalamic tract was shown in the rock cavy (Kerodon rupestris), an endemic rodent of the semiarid region of the Brazilian Northeast, using unilateral intravitreal injections of cholera toxin subunit b as a neuronal tracer. The results reveal that in the rock cavy, besides the suprachiasmatic nucleus, several hypothalamic regions receive direct retinal projection, such as the ventrolateral preoptic nucleus, medial and lateral preoptic areas, the supraoptic nucleus and bordering areas, anterior, lateral and rectrochiasmatic hypothalamic areas, and the subparaventricular zone. The results are discussed by comparing with those of the literature, into a functional context

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The lack of studies aimed at the mental health of the rural population, the social, economic, familial and emotional impact that mental disorders produce and the vulnerability that women have in this context, lead us to believe in the need to investigate the mental health demands of female rural workers, in order to subsidize the development of more effective and culturally sensitive public health programs and policies that take into account the specificities of this population. The present study aims to investigate the prevalence of common mental disorders (CMD) and the possible factors associated with the emergence of such disorders among women living in a rural settlement in Rio Grande do Norte. This survey has a quantitative and qualitative character with an ethnographic approach. As methodological strategies, we made use of an adapted version of the socio-demographic and environmental questionnaire prepared by The Department of Geology/UFRN s Strategic Analysis Laboratory to evaluate the quality of life of the families from the rural settlement and the mental health screening test Self-Reporting Questionnaire (SRQ-20) to identify the prevalence of CMD in adult women from the community. Complementing the role of methodological tools, we use the participant observation and semi-structured interviews with women who presented positive hypothesis of CMD attempting to comprehend the crossings that build the subjective experience of being a woman in this context. The results point to the high prevalence of CMD (43.6%) and suggest the link between poverty, lack of social support, unequal gender relations and the occurrence of CMD. We also verified that the settled women do not access the health network to address issues relating to mental health and that the only recourse of care offered by primary health care is the prescription of anxiolytic medication. In this context, the religiosity and the work are the most important strategies for mental health support among women

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Latices based on acrylic acid and ethyl methacrylate, crosslinked with 1,6‐propoxylate‐hexanodiol diacrylate were synthesized via emulsion polymerization with different monomeric compositions. The resultant latices were thickened with different NaOH/(acrylic acid) molar ratios and were characterized by titrimetry, zeta potential measurements, turbidimetry, and capillary viscometry. Intrinsic viscosity was determined for an uncrosslinked copolymer, using toluene as solvent. All the latices were coagulated with NaCl and washed with water at 60°C analyzed by FTIR spectrophotometry, in order to characterize functional groups from the copolymer and crosslinking agent.