Análise espectroscópica da estrela HD 150050: uma nova estrela gigante rica em lítio

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Nucleação de vortices e paredes de domínio em nanoestruturas magnéticas

We report a theoretical investigation of the magnetic phases and hysteresis of exchange biased ferromagnetic (F) nanoelements for three di erent systems: exchange biased nanoparticles, exchange biased narrow ferromagnetic stripes and exchange biased thin ferromagnetic lms. In all cases the focus is on the new e ects produced by suitable patterns of the exchange energy coupling the ferromagnetic nanoelement with a large anisotropy antiferromagnetic (AF) substrate. We investigate the hysteresis of iron and permalloy nanoparticles with a square basis, with lateral dimensions between 45 nm and 120 nm and thickness between 12 nm and 21 nm. Interface bias is aimed at producing large domains in thin lms. Our results show that, contrary to intuition, the interface exchange coupling may generate vortex states along the hysteresis loop. Also, the threshold value of the interface eld strength for vortex nucleation is smaller for iron nanoelements. We investigate the nucleation and depinning of an array of domain walls pinned at interface defects of a vicinal stripe/AF bilayer. The interface exchange eld displays a periodic pattern corresponding to the topology of the AF vicinal substrate. The vicinal AF substrate consists of a sequence of terraces, each with spins from one AF subalattice, alternating one another. As a result the interface eld of neighboring terraces point in opposite direction, leading to the nucleation of a sequence of domain walls in the ferromagnetic stripe. We investigated iron an permalloy micrometric stripes, with width ranging from 100 nm and 300 nm and thickness of 5 nm. We focused in domain wall sequences with same chirality and alternate chirality. We have found that for 100nm terraces the same chiraility sequence is more stable, requiring a larger value of the external eld for depinning. The third system consists of an iron lm with a thickness of 5 nm, exchange coupled to an AF substrate with a periodic distribution of islands where the AF spins have the opposite direction of the spins in the background. This corresponds to a two-sublattice noncompensated AF plane (such as the surface of a (100) FeF2 lm), with monolayer-height islands containing spins of one sublattice on a surface containing spins of the opposite sublattice. The interface eld acting in the ferromagnetic spins over the islands points in the opposite direction of that in the spins over the background. This a model system for the investigation of interface roughness e ects. We have studied the coercicivity an exchange bias hysteresis shift as a function of the distance between the islands and the degree of interface roughness. We have found a relevant reduction of coercivity for nearly compensated interfaces. Also the e ective hysteresis shift is not proportional to the liquid moment of the AF plane. We also developed an analytical model which reproduces qualitatively the results of numerical simulations

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.

Corpo, movimento e aprendizagem na psicocinética de Jean Le Boulch

School teachers in the discipline of Physical Education, we find ourselves constantly in question of methodological and epistemological issues of practice. This research aims to identify human body understanding, movement and theoretical learning proposed by examining the work of Jean Le Boulch and his approach to Physical Education. We seek to indicate epistemological elements about Physical Education theory and practice, believing that this approach and dialog comes to contribute with this field of knowledge. Boulch, a French teacher of Physical Education, Medicine and Psychology, had an important influence in Brazilian Physical Education during the 1970s and 1980s. His main contribution was teaching courses and knowledge about psychomotricity. Boulch’s studies helped to build knowledge of human movement; considering his importance in people’s development and a critic to a mechanistic view of body and movement. Our reflections will be based on the concepts brought from psychokinetics presented in the bibliographic references of Le Boulch in Brazil, and other references developed by him in this country including conferences, lectures and interviews. This reflection includes the debaters of his work. We chose a theoretical approach referring to the Phenomenology of philosopher Maurice Merleau-Ponty (1999) as a methodological reference considering the influence of his thought in Le Boulch studies. This thesis examines the learning and practice of teaching the Physical Education field of knowledge. We conclude that the body being an entity that exists for itself in the world and that contact with the world starts from human movement. Ultimately, new trains of thought for the teaching of physical education can be set from the reflection of phenomenological concepts brought by Le Boulch in his theory.

A conduta judicial ética teórica e aplicada contida em princípios e regras deontológicos abrangidos pelo sistema constitucional

Research on Legal Deontology dedicated to theoretical and applied ethics on judicial conduct grounded in legal principles and rules set out in the Constitution of the Federative Republic of Brazil and the Organic Law of the National Judiciary, also contemplating propositional instruments covered by the constitutional system, which conveys behavioural paradigms inserted in the Bangalore Principles of Judicial Conduct, in the Universal Statute of the Judge and in the Latin-American Code of Judicial Ethics, as well as highlight the influence of those instruments in the Brazilian Ethical Code of the Magistrates and in the official complementary training of judges in charge of Judiciary Schools. The study provides the theoretical influxes of moral norm, passing by behavioural social norm to consolidate the ideal standards of judicial conduct into legal standards and related instruments. The Legal Deontology directed to the ethical judicial conduct is confronted with the stereotype that society expressed in relation to the judge's person, who is the political agent that interprets the law for making decisions which directly influences the realization of access to justice, that is constitutionally guaranteed to all. Core values inserted in the constitutional system intended to discipline the judicial conduct are presented and analysed under a critical view, since they are enclosed in prescriptive language that conveys behavioural aspects open to interpretation and which compliance is revealed as a proposition focused on promoting a better solution of interest’s conflicts under the responsibility of those who constitute the distinctive corporation of the Judiciary. The theme’s contextualization also focuses on applied ethics, based on the approach of normative and propositional instruments of deontological content, still focusing on the study of real cases examined by the Brazilian National Council of Justice, as part of its correctional goals.

Corpos Queer e a experiência da sexualidade: notas para o conhecimento da educação física

This study had the goal of make a dialogue between queer theory and the thoughts of the French philosopher Maurice Merleau-Ponty in the categories of body and sexuality. From this dialogue, other goals were designed, namely: identify possible recurrences of the experience of bodies and queer sexualities, designed under Merleau-Ponty’s perspective, to the knowledge of Physical Education and reflect on this domain of knowledge using the notions of queer epistemology and esthesia. The study had as methodology the phenomenological attitude proposed by Merleau-Ponty and use the reduction as technic of research. Trying linking these thoughts we used the cinema of the Spanish director Pedro Almodóvar as perceptive strategy, an exercise of look as possibility of reading the world and new ways of perceiving the human being. We appreciate three films, namely: All About My Mother (1999), The Skin I Live In (2011) and Bad Education (2004), which put us in touch with bodies and queer sexualities, with the body of esthesia, of the ecstasy, sensations and lived experiences, un type of art whose contours are not fixed or determinable, postulate by Merleau-Ponty. The philosopher, provide a rich conceptual view of the body and their sexual experience, extends and opens horizons of thought and reflection about queer experience, one experience indeterminate and contingent as a singular way of inhabiting the world. Those horizons opened by the philosopher and added to the queer perspective contribute to put in question the modes of knowledge production and the knowledge about body and sexuality in Physical Education. Finally, we point that this theoretical conversation give us clues to reflect about the reverberations of a queer epistemology for Physical Education usiging one type of knowledge guided by esthesia and sensitivity as marks of another scientific rationality.