487 resultados para Reversão da magnetização


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A dissertação objetiva estudar o papel que o apocalipsismo, desempenhou na história e no contexto da redação do oráculo isaiano em Isaías 24,1-6. A proposta é de que sua função foi de grande importância no processo de formação do judaísmo pós-exílico, fomentando uma nova reidentificação e reetnização dos israelitas-judaítas num contexto de frustração nacionalista e religiosa que gerou uma grande heterogeneidade teológica. Identificamos este contexto como sendo o ambiente em que se deu um complexo processo de transição sócio-teológica na história dos judaitas no período de dominação persa. O apocalipsismo, enquanto fenômeno religioso e sócio-histórico, se mostrou como resultado de uma realidade hostil e desumanizadora na qual a identidade teológico-cultural e os relacionamentos sócioeconômicos das pessoas foram extremamente ameaçados e violentados gerando uma contraposição aos desígnios de Yahweh expressos na aliança firmada por ele para com seu povo. Através da pesquisa e análise exegética de Isaías 24,1-6, a presente dissertação propõe que, a partir dessa realidade conflituosa, a profecia apocalipsista isaiana se manifesta contra as estruturas e suas articulações geradoras de segregação e desumanidade, lançando uma esperança no ato transformador por intermédio de Yahweh, o senhor da história, que possibilita um reverso histórico, a partir do qual será possível reconstruir relacionamentos favoráveis no âmbito social e espiritual.(AU)

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Esta dissertação trata de um tema relativamente novo, com literatura escassa, praticamente sem estudos teóricos que o abordem. Referenciais são encontrados em publicações feitas em seminários e palestras bem como em artigos e notas jornalísticas. Esta dissertação se trata de trabalho exploratório, analítico descritivo com base documental. O Programa Bolsa Família, tema central deste trabalho, é uma ferramenta para distribuição de renda que funciona de forma simples e tem sido efetiva para o atendimento de famílias que vivem abaixo da linha de pobreza. Ele é resultado da fusão de vários outros programas dispersos e com efetividade questionável Bolsa Escola, Auxílio Gás e Cartão Alimentação. O Programa Bolsa Família beneficia famílias em situação de pobreza com renda mensal de R$ 70 a R$ 140 per capita e em extrema pobreza com renda mensal abaixo de R$ 70 reais per capita. Também estabelece condicionalidades de educação e saúde. Atualmente, há cerca de 13 milhões de famílias inscritas no Programa Bolsa Família que cumprem as condições do Cadastro Único esta é praticamente a totalidade das famílias pobres segundo critérios do PNAD 2006 (Pesquisa Nacional de Domicílios). Na realidade, houve substancial injeção de recursos em áreas outrora relegadas ao acaso, criando novos consumidores, bem como empreendedores, além de atrair investimentos. Quanto à educação, nota-se que há redução do analfabetismo. Há um crescimento vegetativo do Índice de Desenvolvimento Humano (IDH) no qual o Brasil situa-se em 84⁰ lugar dentre as 187 nações controladas pelo PNUD (Programa das Nações Unidas para o Desenvolvimento) em 2011. As variáveis que compõem o índice crescem timidamente, destaca-se queda no item expectativa de escolaridade esperada das crianças em idade de ingresso na escola (no Brasil, aos seis anos), que caiu no período 2000-2011, esse fato pode indicar falha estrutural no ensino brasileiro. Esse estudo indica que há desenvolvimento socioeconômico em áreas carentes, particularmente na Região Nordeste. Observa-se também a reversão da migração que historicamente era de norte/nordeste a sudeste. Também nota-se redução da taxa de fecundidade das brasileiras, o que é vantajoso. O Brasil também está com a vantagem do Bônus demográfico , quando a população economicamente ativa supera a população dependente, o que é um excelente fator de crescimento por atrair investimentos. Apesar de melhorias observadas na década 2000-2010, elas ainda são insuficientes. Quanto ao desenvolvimento humano , o Brasil está muito distante das nações desenvolvidas, com IDH de 0,718, que cresceu na última década à taxa de 0,769% ao ano. Nesse ritmo, até alcançarmos o IDH norueguês -- primeiro colocado, ou o australiano -- segundo colocado, que é de 0,943 serão necessários 35/36 anos. Isso nos leva a pensar que, a não ser que o acaso nos ajude, o sonho de nos juntarmos aos primeiros é questionável. Com respeito ao Programa Bolsa Família, esse prova ser uma frente social para a eliminação da desigualdade, seus beneficiários eram classificados como pobres e extremamente pobres e foram resgatados.

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In this work, composites were prepared using high energy mechanical milling from the precursors hydroxyapatite - HAp (Ca10(PO4)6(OH)2) and metallic iron ( -Fe ). The main goal here is to study composites in order to employ them in magnetic hyperthermia for cancer therapy. The produced samples were characterized by X-ray di raction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), magnetization curves as a function of applied eld (MxH), and nally measurements of magnetic hyperthermia. The XRD patterns of the milled samples HAp/Fe revealed only the presence of precursor materials. The SEM showed clusters with irregular shapes. The magnetization curves indicated typical cases of weak ferromagnetic behavior. For samples submitted to grinding and annealing, the identi ed phases were: HAp (Ca10(PO4)6(OH)2), hematite (Fe2O3) and Calcium Iron Phosphate (Ca9Fe(PO4)7). Analyzing the results of MxH, there was a reduction of the saturation magnetization, given that the Fe was incorporated into HAp. Hysteresis curves obtained at 300 K are characteristics of samples possessing over a phase. At 77 K, the behavior of the hysteresis curve is in uenced by the presence of hematite, which is antiferromagnetic. Already at T = 4.2 K, it is observed a weak ferromagnetic behavior. Furthermore, there is the e ect of exchange bias. Regarding the magnetic hyperthermia, the results of temperature measurements as a function of the alternating eld are promising for applications in magnetic hyperthermia and other biomedical applications.

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Located on the western edge of the Brazilian northeast, the Parnaíba Basin is an intra cratonic basin with oil production. This study aims at understanding its genesis and evolution, using aeromagnetic and gravity data. We used the spectral analysis of aeromagnetic data to map the depth to the bottom of the magnetic sources in order to assimilate this depth with the depth of the Curie isotherm, and infer the geothermal gradient. Using the spectral analysis technique, we succeeded in mapping the surface of the depth to the bottom of magnetic sources (SBFM), which marks the depth that occur magnetization. In the Parnaíba Basin the SBFM presented depths around -20,5 and -28,5 , which was consistent with an inversion of the same dataset using the technique of Magnetization Vector Inversion (MVI). Furthermore, SBFM topography correlates well with Moho depth, which was estimated from satellite gravimetric data from the GOCE mission (Gravity Field and Steady-State Ocean Circulation Explorer). Assuming that SBFM coincides with the Curie isotherm of magnetite (ICM), defined as the surface at which magnetite ( ) looses its ferromagnetic properties, it was possible to estimate the geothermal gradient. The geothermal gradient in the basin showed values between 19.2 and 26.5 , allowing to estimate the heat flow for the Parnaíba basin after assuming a conductivity of 2.69 . The resulting heat flow values ranged between 51.6 and 71.3 , which is consistent with values found in other works throughout the South American continent. Lithospheric thickness using an empirical relationship, finding values between -65.8 and -89.2 . We propose that thermal structure of Parnaíba basin is influenced by a deep thermal anomaly. This anomaly has heated the lithosphere beneath the basin and has resulted in relatively thin values for the lithospheric thickness and relatively high surface heat flow values. The origin of the anomaly is not clear, but the correlation between Curie depth and Moho topography, suggests that tectonic extension processes could have played a role.

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The objective was to evaluate spermatogenesis alterations caused by DMD and the effect of the treatment using ascorbic acid in preventing those injuries. Twenty four mice were used, 12 from the C57BL/10 lineage (non-dystrophic) and 12 from the C57BL/10Mdx (dystrophic). The sample was divided in six groups containing 4 animals each, as: C30 = 30 days control; D30 = Dystrophic with 30 days; C60 = 60 days control; D60 = Distrophic with 60 days; CS60 = 60 days control supplemented with ascorbic acid and DS60 = Dystrophic with 60 days supplemented with ascorbic acid. The ascorbic acid supplementation was given in the water, 0,005 mg/day. After euthanasia, the testicles (right and left) were collected, weighted and cross sectioned. The material was fixed in the Karnovsky solution for 24 hours, included in resin for histological studies (morphological and morphometric analyzes) submitted to ultrastructural analysis and immunohistochemistry for caspase-3. There was a significant increase in the tunica propria percentage in D30 compared to C30 and D60. The ultrastructural analysis showed mitochondrial apoptosis evidence of Sertoli cells that can reduce sperm efficiency in CS60 and DS60. A higher volume density of apoptotic cells postivas to Caspase-3 in C30 and D30 versus DS60 compared to CS60. There was severe hypertrophy of the Leydig cells between D30 and D60. However, with supplementation was observed reversal of this change in DS60. The ultrastructure of Leydig cells to early presence of lipid vesicles was observed in the group pre-pubertal dystrophic (D30). Thus, the DMD affect the organization of the seminiferous tubules and intertubule, however, the ascorbic acid supplementation used for the treatment of DMD has been just enough to reduce the hypertrophy of the Leydig cells.

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To identify the relationship between GPS scintillation in Natal-RN (Brazil) and geomagnetic disturbances of any intensities and variations, this work made analysis of the ionospheric behavior and magnetic indexes (Dst , AE and Bz of the interplanetary magnetic field) concerning to different periods of the solar cycle between 2000 and 2014. Part of the data of this research originated at the UFRN observatory, from a GEC Plessey board connected to an ANP -C 114 antenna, modified by Cornell University’s Space group Plasma Physics in order to operate the ScintMon, a GPS monitoring program. This study, therefore, found several cases of inhibited scintillations after the main phase of magnetic storms, a fact that, along with others, corroborated with categorization of Aarons (1991) and models of disturbed dynamo (according to Bonelli, 2008) and over-shielding penetration, defended by Kelley et al. (1979) and Abdu (2011) [4]. In addition to these findings, different morphologies were noted in such disruptions in the GPS signal in accordance with previous magnetic activities. It also found a moderate relationship (R2 = 0.52) between the Dst rate (concerning to specific time) and the average of S4 through a polynomial function. This finding therefore, corroborating Ilma et al. (2012) [17], is an important evidence that the scintillation GPS are not directly controlled by magnetic induction of storms. Completing this work, this relation did show itself as a way of partial predicting of scintillations.

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This work shows that the synthesis by combustion is a prominent alternative to obtain ceramic powders of higher oxides, nanostructured and of high purity, as the ferrites of formulas Co(1-x)Zn(x)Fe2O4 e Ni(1-x)Zn(x)Fe2O4 with x ranging from 0.2 mols, in a range from 0.2 ≤ x ≥ 1.0 mol, that presents magnetic properties in coexistence of ferroelectric and ferrimagnetic states, which can be used in antennas of micro tapes and selective surfaces of low frequency in a range of miniaturized microwaves, without performance loss. The obtainment occurred through the combustion process, followed by appropriate physical processes and ordered to the utilization of the substrate sinterization process, it gave us a ceramic material, of high purity degree in a nanometric scale. The Vibrating Sample Magnetometer (VSM) analysis showed that those ferritic materials presents parameters, as materials hysteresis, that have own behavior of magnetic materials of good quality, in which the magnetization states can be suddenly changed with a relatively small variation of the field intensity, having large applications on the electronics field. The X-ray Diffraction (XRD) analysis of the ceramic powders synthesized at 900 °C, characterize its structural and geometrical properties, the crystallite size and the interplanar spacing. Other analysis were developed, as Scanning Electron Microscopy (SEM), X-ray Fluorescence (XRF), electric permittivity and the tangent loss, in high frequencies, through the equipment ZVB - 14 Vector Network Analyzer 10 MHz-14 GHz, of ROHDE & SCHWART.

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The cobalt-manganese ferrites (Co1¡xMnxFe2O4 and Co1,2Fe1,8¡xMnxO4) has a mixed structure of spinel type and it has been regarded as one of candidates for petitive wide variety of applications in devices from ultrasonic generation and detection, sensors, transformers, as well as in medical industry. Ferrites cobalt-manganese nanostructured were produced via mechanical alloying with subsequent heat treatment and were characterized by X-ray diffraction, X-ray fluorescence, scanning electron microscopy and magnetization. Samples of Co1¡xMnxFe2O4 and Co1,2Fe1,8¡xMnxO4 were obtained from the precursor powders Fe3O4, Co3O4 and Mn3O4 which were stoichiometrically mixed and ground by 10h and heat treated at 900°C for 2h. The diffraction confirmed the formation of the pure nanocrystalline phases to series Co1,2Fe1,8¡xMnxO4 with an average diameter of about 94nm. It was found that the lattice parameter increases with the substitution of Fe3Å by Mn3Å. The x-ray fluorescence revealed that the portions of metals in samples were close to the nominal stoichiometric compositions. The microstructural features observed in micrographs showed that the particles formed show very different morphology and particle size. The magnetic hysteresis measurements performed at low temperature showed that the saturation magnetization and remanence increased as the concentration of manganese, while the coercive field decreased. The anisotropy constant (Ke f ), was estimated from the data adjustments the law of approaching saturation. It was found that the anisotropy decreases substantially with the substitution of Fe by Mn.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq

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Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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This Thesis comprises a theoretical study about the influence of the magnetocrystalline anisotropy on the static and dynamic magnetic properties of nanofilms: monolayers and trilayers coupled through the bilinear and biquadratic exchange fields, for situations in which the systems are grown in unusual [hkl] asymmetric directions. Using a theory based on a realistic phenomenological model for description of nanometric systems, we consider the total free magnetic energy including the Zeeman interaction, cubic and uniaxial anisotropies, demagnetizing and surface anysotropy energies, as well as the exchange terms. Numerical calculations are conducted by minimizing the total magnetic energy from the determination of equilibrium static configurations. We consider experimental parameters found in the literature to illustrate our results for Fe/Cr/Fe trilayer systems. In particular, a total of six different magnetic scenarios are analyzed for three regimens of exchange fields and the [211] and [321] asymmetric growth directions. After numerically minimize the total energy, we use the equilibrium configurations to calculate magnetization and magnetoresistance curves with the respective magnetic phases and corresponding critical fields. These results are also used to establish the boundary for occurrence of saturated states. Within the context of the spin waves, we solve the equation of motion for these systems in order to find the respective associated dispersion relations. The results show similar magnetization and magnetoresistance curves for both [211] and [321] growth scenarios, including an equivalent magnetic transition behavior. However, the combination of those peculiar symmetries and influence of the exchange energies results in attractive properties, including the generation of magnetic states as a function of the asymmetric degree imposed in the [hkl] growth orientations. There is also an increasing incompatibility between the values of saturation fields of magnetization and magnetoresistance for the cases in which a magnetic field acts along intermediate cubic anisotropic axes, particularly in the situations where the bilinear and biquadratic exchange fields are comparable. The dispersion relations and static results are consistent, the corresponding magnetic states are also present in both acoustic and optical modes. Furthermore, Goldstone excitations are also observed for that particular cases of a magnetic field acting in the intermediate axes, an effect related to transitions of second order and to the spontaneous symmetry breaking imposed by the combination of the biquadratic energy with the cubic and uniaxial anisotropies.

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Background: The inspiratory muscle training (IMT) has been considered an option in reversing or preventing decrease in respiratory muscle strength, however, little is known about the adaptations of these muscles arising from the training with charge. Objectives: To investigate the effect of IMT on the diaphragmatic muscle strength and function neural and structural adjustment of diaphragm in sedentary young people, compare the effects of low intensity IMT with moderate intensity IMT on the thickness, mobility and electrical activity of diaphragm and in inspiratory muscles strength and establish a protocol for conducting a systematic review to evaluate the effects of respiratory muscle training in children and adults with neuromuscular diseases. Materials and Methods: A randomized, double-blind, parallel-group, controlled trial, sample of 28 healthy, both sexes, and sedentary young people, divided into two groups: 14 in the low load training group (G10%) and 14 in the moderate load training group (G55%). The volunteers performed for 9 weeks a home IMT protocol with POWERbreathe®. The G55% trained with 55% of maximal inspiratory pressure (MIP) and the G10% used a charge of 10% of MIP. The training was conducted in sessions of 30 repetitions, twice a day, six days per week. Every two weeks was evaluated MIP and adjusted the load. Volunteers were submitted by ultrasound, surface electromyography, spirometry and manometer before and after IMT. Data were analyzed by SPSS 20.0. Were performed Student's t-test for paired samples to compare diaphragmatic thickness, MIP and MEP before and after IMT protocol and Wilcoxon to compare the RMS (root mean square) and median frequency (MedF) values also before and after training protocol. They were then performed the Student t test for independent samples to compare mobility and diaphragm thickness, MIP and MEP between two groups and the Mann-Whitney test to compare the RMS and MedF values also between the two groups. Parallel to experimental study, we developed a protocol with support from the Cochrane Collaboration on IMT in people with neuromuscular diseases. Results: There was, in both groups, increased inspiratory muscle strength (P <0.05) and expiratory in G10% (P = 0.009) increase in RMS and thickness of relaxed muscle in G55% (P = 0.005; P = 0.026) and there was no change in the MedF (P> 0.05). The comparison between two groups showed a difference in RMS (P = 0.04) and no difference in diaphragm thickness and diaphragm mobility and respiratory muscle strength. Conclusions: It was identified increased neural activity and diagrammatic structure with consequent increase in respiratory muscle strength after the IMT with moderate load. IMT with load of 10% of MIP cannot be considered as a placebo dose, it increases the inspiratory muscle strength and IMT with moderate intensity is able to enhance the recruitment of muscle fibers of diaphragm and promote their hypertrophy. The protocol for carrying out the systematic review published in The Cochrane Library.

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In this work are considered two bidimensional systems, with distints chacacteristcs and applicabilitys. Is studied the adsorption of transition metals (MT) Fe, Co, Mn and Ru in extended defects, formed by graphene grain boundaries. First in pristine graphene The hollow site of carbon hexagon, in pristine graphene, are the most stable for MT adsorption. The Dirac cone in eletronic structure of graphene was manteined with the presence of MT. For the considered grain boundaries the MT has a greater stability for absorption in the grain boundaries sites in comparison with pristine graphene. Through the energy barrier values, are observed diffusion chanels for MT localized on the grain boundaries. This diffusion chanels indicate a possible formation of nanolines of MT in graphene. For the first stage of the nanolines, ate observed a better stability for the system with greater MT concentration, due to MT-MT interactions. Also, due to the magnetic moment of the MT, the nanolines show a magnetization. For the most stable configurations the system are metallics, particularly for Fe the band structure indicates an anisotropic spin current. In a second study, are considereted the retention capacity for metallic contaminants Cd and Hg in clayminerals, kaolinite (KAO) and montmorillonite (MMT). Through the adsorption energies of contaminantes in the clayminerals, was observed a increase in stability with the increase of contaminants concentration, due to the interaction Cd-Cd and Hg-Hg. Also, was observed that KAO has a strong interaction beteween monolayers than MMT. In this sence, for the adsoption process of contaminantes in the natural form of KAO and MMT, the latter has a better retention capacity, due to the small net work for contaminant intercalation. However, when the modification of clayminerals, with molecules that increase the spacing between monolayers, exist a optimal condition, which the contaminant absorption are more stable in KAO system than in MMT. In the Langmuir adsorption model for the clayminerals in the optimal monolayer spacing, the retention capacity for Cd and Hg in KAO system are 21% greater than in MMT system. Also, for the X-ray Absorption Near Edge Spectroscopy (XANES) for the K edge of Cd and Hg, are found a positive shift of absorption edge with the decreasing of monolayer spacing. This result indicates a possible way to determine the concentration of adsorbed contaminats in relation to unabsorbed ones, from the decomposition of experimental XANES in the obteined spectras.