Estudo da densidade de corrente crítica para reversão da magnetização de nanoelementos ferromagnéticos

The discovery that a spin-polarized current is capable of exerting a torque in a ferromagnetic material, through spin transfer, might provide the development of new technological devices that store information via the direction of magnetization. The reduction of current density to revert the magnetization is a primary issue to potential applications on non volatile random access memories (MRAM). We report a theorical study of the dipolar and shape effects on the critical current density for reversal of magnetization, via spin transfer torque (STT), on ferromagnetic nanoelements. The nanostructured system consists on a reference layer, in which the current will be spin-polarized, and a free layer of magnetization reversal. We observed considerable changes on the critical current density as a function of the element’s reversion layer thickness (t = 1.0 nm, 1.5 nm, 2.0 nm e 2.5 nm) and geometry (circular and elliptical), the material kind of the system free layer (Iron and Permalloy) and according to the orientation of the magnetization and the spin polarization with the major axis. We show that the critical current density may be reduced about 50% by reducing the Fe free layer thickness and around 75% when we change the saturation magnetization of circular nanoelements with 2.5 nm of thickness. We still observed a reduction as much as 90% on the current density of reversion for thin nanoelements magnetized along the minor axis direction, using in-plane spin polarization parallel to the magnetization.

O regime da memória através dos diários virtuais: o caso dos blogs

CARVALHO, Luciana Moreira.;CARVALHO, Monica Marques. O registro da memória através dos diários virtuais:o caso dos blogs.Em Questão, Porto Alegre, v. 11, n. 1, p. 53-66, jan./jun. 2005.ISSN 1808-5245. Disponivel em:. Acesso em: 04 out. 2010. ão

Identidade, memória e narrativas na dança de São Gonçalo do povoado Mussuca (SE)

This study deals with the participation of the dance of São Gonçalo of the Mussuca town/SE, in the process of construction of the ethnic identity among this social group. The Mussuca is a grouping recognized as afro-descendents, linked with black enslaved people in the valley of the Cotinguiba region. The collective memory functions as a drive of this linking with the past and if it makes to elaborate narratives on this descent. The objective of this study was to investigate the ways the rite went through to constitute itself as an element of ethnic representation. Internal and external agents had been identified who had participated in different contexts. By means of an ethnographic work we ve reached some aspects of the local structure social which demonstrated the contradictions through the social relations of the group. This process of ethnic autorecognition presents the kinship and the space question as definers of the social arrangements which establish its ethnic boundaries

De volta para os braços da rainha dos céus: migração, memória e festa em Caicó/RN

The present work has as an objective to seize up some particular meanings of the Feast of Sant Ana (The saint which represents the city of Caicó/RN), a central event of the calendar festive-religious of that city, looking for to perceive on how it combines with the symbolic poles sacred: profane through the social bonds that are present there performed and expressed through the social networking and of local belongings. Such bond ties reveal themselves through a very especial manner, through the migration of returning to the feast, when collectively are produced and updated knowledge and codes that reinforce the representation of the local belonging, nominated as being caicoense . We seek on perceiving how the many events of this feast (from a perspective of a religious order as well as laic) acting on a conclusive way to an identity of the re-meaning of that city, especially in its relation with the migrant natives: the sons and daughters that return to the arms of Sant Ana

Caldo do caldo: memória do espetáculo de dança paraibano caldo da cana

This research investigated the dance piece Caldo da Cana which premiered in João Pessoa-PB, in September 1984. It problematizes theoretical and practical way to make dance history, investigating this possibility through the dance itself. Arises from the fact that the dance has specific characteristics that can not be neglected by the historical account. In this sense, it was initiated by the raising of a theoretical framework that speaks to the indicated issues and unfolds through a field study, which included collecting testimonies from people who participated in the show, documentary research, gathering material traces and finally consists a practical part by transposing elaborated historical knowledge into the body through a creative process, resulting on this moment, in the construction of a duo dance

Perfil de memória e ativação de linfócitos T na leishmaniose visceral

Visceral leishmaniasis (VL) in Brazil is a disease caused by Leishmania infantum chagasi (L.i.chagasi). The clinical evolution post-infection depends on the vertebrate host immune response, which is genetically mediated. This study aimed to evaluate the immune response of individuals living in endemic area for VL in the state of the Rio Grande do Norte, considering individuals with VL under treatment (n = 9), recovered VL <1 year post treatment (n = 10), > 10 years posttreatment (n = 9), uninfected individuals living in endemic areas (n = 7), individuals that lost DTH response (n=6) and asymptomatic individuals for VL (n=9). Peripheral blood cells were evaluated in the presence and absence of soluble Leishmania antigens (SLA) and ex vivo, to determine activation, presence of regulatory cells and memory cells. The Leishmania parasitemia and anti-Leishmania antibodies were determined respectively by qPCR and ELISA. Cells from individuals with VL under treatment showed less cell activation after stimulation with SLA for the markers CD4/CD69, CD8/CD69 and CD8/CD25 compared with VL post treatment treatment (p <0.001). Apparently uninfected individuals have a higher cell activation than symptomatic VL (p <0.001), with the exception of CD8/CD25 marker (p = 0.6662). On the other hand, in the ex-vivo group, significant differences were observed for CD4/CD69, CD8/CD69 and CD8/CD25 between the 4 groups due to increased cell activation present in cells of individuals symptomatic LV (p <0.001). VL cells under treatment, ex vivo, have a lower percentage of memory cells (CD4/CD45RO and CD8/CD45RO) than individuals VL post-treatment or control group (p = <0.01). Likewise, individuals with symptomatic VL have fewer regulatory cells when stimulated by SLA [CD4/CD25 (p = 0.0022) and CD4/FOXP3 (p = 0.0016)] and in the ex-vivo group (p = 0.0017). Finally, DNA isolated from recovered VL contained Leishmania DNA, supporting the hypothesis of non-sterile clinical cure for Leishmania infection. Recovered VL, even 10 years after treatment have high levels of memory cells, which may be due to the presence of stimulation, either by reexposure to Leishmania or non-sterile cure

Estudo da síntese e propriedade magnética de ferritas de manganês/cobalto dopadas com níquel

For the chemical method of synthesis of co-precipitation were produced ferrite powders manganese-cobalt equal stoichiometric formula Mn (1-x) Co (x) Fe2O4, for 0 < x < 1, first reagent element using as the hydroxide ammonium and second time using sodium hydroxide. The obtained powders were calcined at 400 ° C, 650 ° C, 900 ° C and 1150 ° C in a conventional oven type furnace with an air atmosphere for a period of 240 minutes. Other samples were calcined at a temperature of 900 ° C in a controlled atmosphere of argon, to evaluate the possible influence of the atmosphere on the final results the structure and morphology. The samples were also calcined in a microwave oven at 400 ° C and 650 ° C for a period of 45 minutes possible to evaluate the performance of this type of heat treatment furnace. It was successfully tested the ability of this group include isomorphic ferrite with the inclusion of nickel cations in order to evaluate the occurrence of disorder in the crystalline structures and their changes in magnetic characteristics.To identify the structural, morphological, chemical composition and proportions, as well as their magnetic characteristics were performed characterization tests of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDX), thermogravimetric (TG), vibrating sample magnetometry (MAV) and Mössbauer spectroscopy. These tests revealed the occurrence of distortion in the crystal lattice, changes in magnetic response, occurrence of nanosized particles and superparamagnetism

Hemiparesia congênita e adquirida na criança: interrelação entre presença de crises epilépticas, os achados eletrencefalográficos e de neuroimagem por ressonância nuclear magnética

The purpose of this paper was to study patients with congenital and acquired hemiparesis, their clinical aspects, the presence or not of epileptic seizures, and electroencephalographic (EEG) and Magnetic Resonance Imaging (MRI) findings. We analyzed the interrelation between etiology, the presence and seriousness of epileptic seizures (ES) and the possible causes of refractoriness. This is a prospective study using the clinical diagnosis of a child neurologist, who attested to the presence of unilateral motor lesions. We compared the electroencephalographic findings in patients with or without epileptic seizures, and investigated if among the former, these seizures were controlled or not, their likely etiology and risks of refractoriness. EEG background activity on the lesion and contralateral side was analyzed, in addition to the presence of concomitant epileptiform activity. Encephalon MRIs of all the patients were studied to correlate etiology and the control or not of epileptic seizures. The disorganization of bilateral EEG activity correlated with the difficult-to-control epileptic seizures. Suitably organized background activity contralateral to the lesion is a good prognosis in relation to epileptic seizures. Focal epileptogenic activity does not necessarily predispose to epileptic manifestation. The MRI is more important in determining etiology than in prognosing epileptic seizures. This study used a multidisciplinary approach involving child neurologists, a physical therapist and a neuroradiologist. This meets the criteria of multidisciplinarity of the Postgraduate Program in Health Sciences

Medidas de parâmetros morfológicos e funcionais do Coração em brasileiros: um subestudo do primeiro registro multicêntricos latino-americano em ressonância magnética cardiáca

There is no data about cardiac measurements em Brazilians obtained by CMR. This a muldisciplinary study with the objective of obtaining measurements of the left ventricle (LV) and right ventricle (RV) diastolic diameter (Dd), systolic diameter (Ds), diastolic volume (Dv), systolic volume (Sv), ejection fraction (EF) and myocardial mass in Brazilians. One hundred and seven (54 men and 53 women, mean age of 43.4 ± 13.1 years) asymptomatic individuals without heart disease were submitted to cardiac magnetic resonance (cMR) studies using steady state free precession technique. The means and standard deviations of the parameters of the LV and RV were respectively: LVDD = 4,8 ± 0,5 cm; LVSD = 3,0±0,6 cm; LVDV = 128,4±29,6 ml; LVSV = 45,2±16,6 ml; LVEF = 65,5±6,3%; LV mass = 95,2±30,8.1 g; RVDD = 3,9±1,3 cm; RVSD = 2,5±0,5 cm; RVDV = 126,5±30,7 ml; RVSV = 53.6±18,4 ml; RVEF = 58.3±8,0.0% and RV mass = 26,1±6,1 g. The masses and volumes were significantly higher in men, except for the LVSV. The RV EF was significantly higher in women. There was inverse correlation between RV systolic volume and with age, being more significant in men. This study describes for the first time benchmarks for cardiac measurements obtained by CMR among asymptomatic Brazilians individuals without heart disease and demonstrated differences according to sex and age

Memória e cultura: os Fulni-ô afirmando identidade étnica

Ce travail s agit du processus d´affirmation de l´identité Fulni-ô et de la mobilisation ethnique du groupe qui sont organisées et maintenues en bénéfice de leurs droits; ceux-ci consistent en la reconnaissance comme indiens devant la société et leurs droits sur le territoire. Le groupe est situé dans la municipalité d´Águas Belas, localisé entre l´ agreste et le sertão de l´état du Pernambuco. Ce sont, en moyenne, 3.676 indiens qui présentent comme signes d´identification ethnique: le Yathê, langue spécifique du groupe qui continue à être utilisée au quotidien; l´Ouricuri, terme qui désigne le rituel qui a lieu pendant le printemps et pendant des périodes spécifiques de l´année; le Toré, danse commune aux indiens du Nordeste. La mémoire et la matière culturelle sont les signes de mobilisation ethnique sélectionnés par les Fulni-ô pour favoriser l´affirmation de leur identité et la protection de leurs droits. Cet aspect sera traité tout au long de ce travail. La mobilisation ethnique est permanente, les Fulni-ô ne cessent d´utiliser des moyens qui peuvent les aider à vivifier leur identité et à protéger l´intégrité de leur territoire. Au travers de la mémoire ou grâce à l´utilisation de signes et de symboles ethniques (comme la langue, le rituel religieux et le Toré) ils consolident l´idée qu´ils sont indiens en même temps qu´ils établissent et défendent leurs frontières ethniques et physiques

Dadi e o teatro de bonecos: memória, brinquedo e brincadeira

The puppet theater is the theme of this dissertation, with a particular treatment of Memory, Toy and Jokes, focused especially on a Calungueira, maker of dolls, Ieda Maria Medeiros da Silva, known by Dadi. Currently with 71 years old, Dadi resides in Carnauba dos Dantas / RN and not only restricted to "get" the dolls to play, to enact stories by various characters. Build the dolls, dresses, give life, movement. In Rio Grande do Norte, the Puppet Theater, named "João Redondo," is measured by a historically male character of tradition, represented by some masters who have died or by their pupils, or even by the players who have no lineage of masters in their families but learned from several of them and, gradually, were included in this playful universe. Dadi passes this potiguar genealogy and going to suggesting a variety of transgressions, beyond, with its inventiveness, both in their presentations and in her life, which I did elect her and choose as a singular object in the course of my inquiries. In this study, I use the theoretical and methodological framework of social sciences, in particular the references coming from studies of culture, such as approaches of memory and tradition of authors such as Maurice Halbwachs and Paul Zumthor, among others. The field work was systematized, prioritizing the observation participant and permanent dialogue. I used different strategies for registration, as semi-open interviews, documentary video, audio narratives, photographic and videographic record, giving the work a current relevance to the dialogue with various elements, expanding the initial project, which turned into research for the dissertation

Vivendo do mar: tradição, memória e mudança na vida pesqueira de Pitangui-RN

This research focuses on the fishery activity, aligned to knowledge of past generations, and the transformation to those who depend on this activity for their livelihood, at the seashore community of Pitangui in Extremoz municipality, which lies 40 km away from Natal, seat of the state of Rio Grande do Norte. The intense modernization which has taking place during the last few years may be considered the result of a number of economic, social and cultural factors, as the introduction of new fishery technology. On the other hand, the present study seeks to show how this changing process happened, and to what extent those affected understand and evaluate this transformation. The methodology to carry out the ethnographic work was mainly adopted by qualitative methods and techniques - by participant observation, oral history, photography and the audiovisual records besides reference to data extracted under quantitative methods, as an important instrument of analyses. This induces a conclusion that the transformation of the community is a consequence of the globalized market, though still tied up to specific local relations. The emerging results are: the use of new fishery technology, and new ways of orientation and navigation; the opening to new jobs and occupational activity, the re-order of space s appropriation; changing sociability, larger access to consumer goods, besides bringing on some new conflicts land appropriation and the fishery and the protection of the environment. All this comprehended as a result of the movement of the local relations participating in the global spaces

Auta de Souza, a poeta de pele clara, um moreno doce : memória e cultura da intelectualidade afrodescendente no Rio Grande do Norte

In the first half of the twentieth century different groups of intellectuals were engaged in the pursuit of an ideal of Brazility. Thereon, two currents are perceived. The first was marked by a nostalgic bias about the past, being formulated by intellectuals from the region that was turning as Northeast. This group of intellectuals emphasized values and traditions of the agrarian aristocracy of the region that was losing visibility in the political and economic Brazil scene. Already the other current has a more modern and industrial feature, was formed by intellectuals from the Southeast that in detriment of the first, was rising. This group, on the other hand, was intended to give a new face to Brazil and break with the "roots" of our delay that in their view were linked to our agrarian past. This resulted in different perceptions and interpretations of our historical past, and the construction of different profiles to the Brazilian. Accordingly, our work seeks to understand how was produced the writing that silenced the mixed ancestry of Auta de Souza (1876-1901) considering the position that she should occupy in the intellectuals projects who were in charge of forming a memory for our state. Auta as a relevant historical character in this project of potiguares intellectuals, she was raised to the condition of a model woman and elected in the pantheon of the most beloved poets of Rio Grande do Norte, however, to occupy such prestigious position she had her racial ancestry concealed in the writings that these same intellectuals had written about her, what is still spreaded in memory and rituals places of religious and civic features

O tempo das brincadeiras : memória, turismo e tradição em Barra do Camaratuba PB

Barra do Camaratuba belongs to Mataraca city, nearby the boarder between Paraíba and Rio Grande do Norte states. It was the chosen community to develop this research, objectifying to study the set of practical of the cultural manifestations and the implications of the local tourist activity, considering the cultural dynamics. We tried to reconstruct stories from the narratives of the oldest inhabitants, natives, among others that they had lived, some how, individual and collective experiences related to the popular tricks and the traditional parties, considering what they speak and imagine about their experiences and its culture. The Lapinha, the Pastoril, the viola s songs, the Balls of Concertina, the João Redondo, the Ox of Kings, the wheel of Coconut were common practical perceivable through the communitarian bonds. Among these manifestations, the only one that resisted for a longer time was the wheel coconut. The São Pedro s fest is another popular manifestation that appears on the current scene like the padroeiro party, while others cultural practical compose the spectacle s scenery. These questions cover many of the narratives of the interviewed ones in the interlaced thing between memory, tourism and tradition. Therefore, we tried to build our research from the memory, participant observation, orality, techniques of the life history, personal depositions, among others basic methods for the reconstruction of a collective memory . Speaking about the past of Barra do Camaratuba is to live again the parties, the blood relations, the terço , the work in the roçados , in the flour house, the fishing, the leisure and the habits of the daily life. In this community, there is the presence of conflicts of social and cultural order, caused for the hegemonic classes that sponsor the parties. In the padroeiro party we perceive that the mercantile logic has started, very recently, to transform the religious factor into an excuse to put into motion the local economy. This way, a community originated from artisan fishers and agriculturists, having the fishing practical as a way of subsistence and the tricks as a reference, they had started to compose a new social picture with the arrival of the others and with the presumption and recent tourist development. We perceive social, environmental and cultural impact transformations, exemplified by a non planned activity or a predatory tourism. The changes will always be pointed and compared with other passing in a sphere of relations lived by the natives, local players and fishers

Entre a Anta e a Cruz: história e memória da cidade de Nova Cruz - RN

Dans ce travail, nous étudions la construction narrative du passé de la ville de Nova Cruz, dans l´agreste potiguar. Les récits soulignent l´existence d´un corpus narratif homogène qui fait référence à l´occupation du lieu et à l´évangelisation de ses habitants. Ainsi, les images des saints et des missionaires civilisateurs de l´espace qui domestiquent les manifestations d´un esprit autochtone sauvage, habitants du milieu naturel, sont recurrentes dans la description des personnages du passé. Observant la continuité sémantique des différentes versions de l´histoire de la ville, nous nous proposons d´analyser d´une manière conjointe les textes de l´historiographie locale et les témoignages oraux collectés. Comme il a été possible de le constater, les chemins de l´écrit et de l´oral se croisent en plusieurs occasions, obéissant à des logiques locales de représentations du passé. Ainsi, notre étude porte sur des champs communs à l´Anthropologie, à l´Histoire e à la Littérature. Les reconstructions narratives du passé local sont aussi activées par des faits plus récents, des "marques de la mémoire" comme le marché, le train, la croix et le réservoir, symboles d´une époque d´abondance qui suit l´action civilisatrice des personnages ancestraux