Infrared degrees of freedom of Yang-Mills theory in the Schrodinger representation

We set up a new calculational framework for the Yang-Mills vacuum transition amplitude in the Schrodinger representation. After integrating out hard-mode contributions perturbatively and performing a gauge-invariant gradient expansion of the ensuing soft-mode action, a manageable saddle-point expansion for the vacuum overlap can be formulated. In combination with the squeezed approximation to the vacuum wave functional this allows for an essentially analytical treatment of physical amplitudes. Moreover, it leads to the identification of dominant and gauge-invariant classes of gauge field orbits which play the role of gluonic infrared (IR) degrees of freedom. The latter emerge as a diverse set of saddle-point solutions and are represented by unitary matrix fields. We discuss their scale stability, the associated virial theorem and other general properties including topological quantum numbers and action bounds. We then find important saddle-point solutions (most of them solitons) explicitly and examine their physical impact. While some are related to tunneling solutions of the classical Yang-Mills equation, i.e. to instantons and merons, others appear to play unprecedented roles. A remarkable new class of IR degrees of freedom consists of Faddeev-Niemi type link and knot solutions, potentially related to glueballs.

Desencantamento do mundo e ética na ação pedagógica: reflexões a partir de Max Weber

This article has a theoretical character and presents some of Weber's ideas, with emphasis on those that can supply elements to reflect on the current state of education, more particularly based on his understanding of modernity. Disenchantment of the world is the key concept in his sociology, and is taken as the basis for a reflection about the meaning that science and the teacher can have today. A classic author, Weber's interpretation of the modern world brings to our consideration a variety of themes that influence markedly the thinking and practice of contemporary culture by its concern with understanding human actions and values. By studying the Western process of rationalization, he initiates debates in science, in ethics and, correspondingly, in education, allowing us to expand our comprehension of the meaning, significance, and role of our actions towards knowledge and teaching. The main object of education is to offer students contents that stimulate the freedom of thought. For that, the teacher needs to adopt a non-partisan ethics in the classroom, presenting contents unbiased by her/his political opinions and, if failing to do so, having the honesty to explain what she/he is doing. It is therefore of the utmost importance that the teacher should keep a neutral position, so that in and out of the classroom the students may reflect and question what they see, experiment and decide upon. Only then the conduct of the teacher will be consistent with the process of rationalization of our culture.

Práticas teatrais na educação: será que dá jogo?

Pós-graduação em Artes - IA

Extension of the Nambu-Jona-Lasinio model predictions at high densities and temperatures using an implicit regularization scheme

Traditional cutoff regularization schemes of the Nambu-Jona-Lasinio model limit the applicability of the model to energy-momentum scales much below the value of the regularizing cutoff. In particular, the model cannot be used to study quark matter with Fermi momenta larger than the cutoff. In the present work, an extension of the model to high temperatures and densities recently proposed by Casalbuoni, Gatto, Nardulli, and Ruggieri is used in connection with an implicit regularization scheme. This is done by making use of scaling relations of the divergent one-loop integrals that relate these integrals at different energy-momentum scales. Fixing the pion decay constant at the chiral symmetry breaking scale in the vacuum, the scaling relations predict a running coupling constant that decreases as the regularization scale increases, implementing in a schematic way the property of asymptotic freedom of quantum chromodynamics. If the regularization scale is allowed to increase with density and temperature, the coupling will decrease with density and temperature, extending in this way the applicability of the model to high densities and temperatures. These results are obtained without specifying an explicit regularization. As an illustration of the formalism, numerical results are obtained for the finite density and finite temperature quark condensate and applied to the problem of color superconductivity at high quark densities and finite temperature.

Três versões do pragmatismo deweyano no Brasil dos anos cinqüenta

O presente texto parte de uma caracterização em que o movimento escolanovista brasileiro é considerado como difusor da introdução de procedimentos científicos no campo pedagógico, como se a educação devesse subordinar-se às regras do pensamento e às descobertas obtidas pela ciência. em seguida, mostra que essa caracterização descreve apenas uma das tendências do ideário educacional renovador, sendo que outra, desenvolvida marcadamente sob a influência de John Dewey, filósofo e educador norte-americano, apresenta norteamentos bastante diversos. Assim, analisa alguns artigos publicados na Revista Brasileira de Estudos Pedagógicos, órgão do Instituto Nacional de Estudos Pedagógicos, INEP, nos anos de 1950. Tais artigos, de autoria de Anísio Teixeira, João Roberto Moreira e Luiz Alves de Mattos, entre outros, traduzem o ideário educacional renovador daquele período e expressam concepções fundamentadas nas idéias de John Dewey. Os temas debatidos por esses educadores brasileiros são agrupados, de maneira geral, em torno das seguintes categorias: democracia, liberdade, pesquisa sócio-educacional e planejamento educacional. Na análise desenvolvida, percebe-se que os autores expressam diferentes visões do mesmo pensador - John Dewey -, fato que é compreensível mediante o conceito de recontextualização, originário das teses de Basil Bernstein, segundo o qual as teorias ou concepções filosóficas sofrem alterações, muitas vezes fundamentais, quando são convertidas em discurso pedagógico. Ao mesmo tempo que espera contribuir para melhor compreensão da presença do pensamento deweyano no Brasil, o presente trabalho também sugere a necessidade de maior aprofundamento quanto ao estudo dos processos recontextualizadores no campo educacional.

Risco, incerteza e as possibilidades de ação na saúde ambiental

O conceito de risco vem tendo uso crescente no entendimento das relações entre saúde e ambiente. Uma revisão recente do seu emprego¹ mostrou que o risco é próprio da condição humana e que a exclusão da incerteza promove a manutenção do status quo. O problema que se coloca é como propor ações de melhoria na saúde ambiental sob os pressupostos da dúvida e da incerteza que caracterizam a condição de risco. Como proposta de solução, a obra de H. Arendt² prestou-se ao exame dos significados e das implicações da incerteza no campo do pensamento e no campo da ação. Os resultados mostram que o risco se insere na lacuna construída entre o passado e o futuro. Quando esta lacuna passa a ser entendida como espaço de possibilidades, a incerteza, produzida no campo do pensamento fomenta a liberdade e a participação no campo da ação. A valorização da subjetividade e o exercício do juízo promovem a configuração de novos contextos e de novas possibilidades de ação, tanto em relação à natureza como em relação aos homens. Este conhecimento novo se insere na lacuna entre passado e futuro e realimenta o processo. Conclui-se que as ações de promoção da saúde devem estar aptas a aceitar resultados não necessariamente idealizados. Na ação livre não existem certezas e a sua relevância não está nos fins que se possa estabelecer, mas no processo do seu exercício.

Conformational basis for the biological activity of TOAC-labeled angiotensin II and bradykinin: Electron paramagnetic resonance, circular dichroism, and fluorescence studies

N-Terminally and internally labeled analogues of the hormones angiotensin (AII, DRVYIHPF) and bradykinin (BK, RPPGFSPFR) were synthesized containing the paramagnetic amino acid 2,2,6,6-tetramethylpiperidine-1-oxyl-4-amino-4- carboxylic acid (TOAC). TOAC replaced Asp 1 (TOAC 1-AII) and Val 3 (TOAC 3-AII) in AII and was inserted prior to Arg 1 (TOAC 0-BK) and replacing Pro 3 (TOAC 3-BK) in BK. The peptide conformational properties were examined as a function of trifluoroethanol (TFE) content and pH. Electron paramagnetic resonance spectra were sensitive to both variables and showed that internally labeled analogues yielded rotational correlation times (TC) considerably larger than N-terminally labeled ones, evincing the greater freedom of motion of the N-terminus. In TFE, τ C increased due to viscosity effects. Calculation of τ Cpeptide/τ CTOAC ratios indicated that the peptides acquired more folded conformations. Circular dichroism spectra showed that, except for TOAC 1-AII in TFE, the N-terminally labeled analogues displayed a conformational behavior similar to that of the parent peptides. In contrast, under all conditions, the TOAC 3 derivatives acquired more restricted conformations. Fluorescence spectra of All and its derivatives were especially sensitive to the ionization of Tyr 4. Fluorescence quenching by the nitroxide moiety was much more pronounced for TOAC 3-AII The conformational behavior of the TOAC derivatives bears excellent correlation with their biological activity, since, while the N-terminally labeled peptides were partially active, their internally labeled counterparts were inactive [Nakaie, C. R., et al., Peptides 2002, 23, 65-70]. The data demonstrate that insertion of TOAC in the middle of the peptide chain induces conformational restrictions that lead to loss of backbone flexibility, not allowing the peptides to acquire their receptor-bound conformation. © 2004 Wiley Periodicals, Inc.

Do monopólio à livre concorrência: a liberdade religiosa no pensamento de Tavares Bastos (1839-1875)

Pós-graduação em História - FCLAS

Quantization of unstable linear scalar fields in static spacetimes

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

Intelectuais, literatura e imprensa no pós-golpe

Culture and the arts in Brazil were impacted directly by the military coup from 1964 onwards. In spite of repression and censorship, the activity of intellectuals and artists in the pre-1964 period was not interrupted nor became stagnant, but gained even greater force due to the presence of control and restrictions by the institutions of repression over against the freedom of creation and thought. As in many sectors of cultural production, literature played a vigorously combative role against the arbitrariness of the regime and implemented “projects of resistance” on the basis of key elements of representation. This occurred, for instance, through the writing and circulation of works such as Pessach: a travessia, by journalist Carlos Heitor Cony, and Quarup, by journalist Antonio Callado. The two novels enabled a broad debate on the narrative form and the scope of involvement in the literature of the 1960s, such as the confrontation between Paulo Francis and Ferreira Gullar in the pages of Revista Civilização Brasileira, which is the focus of this article.

The Role of the (In)visible and the Secret in the Translation of Harryette Mullen s Muse & Drudge

This paper, based on Jacques Derrida’s thoughts in Des Tours of Babel, addresses the issue regarding the (in)visible in translation, by arguing that the latter, beyond the traditional conception of communication, produces a complex set of relations between the visible and the invisible, which highlights the values of the non-dit and the secret that take place in their relation to interpretation. This line of thought underpins the discussion of my translation of two poems from Muse & Drudge (1995), by the African-American poet Harryette Mullen, whose dense poetry displays un(expected) possibilities of meanings and associations that proliferate in translation. It is argued that every act of translation entails a relationship between that which is translated (and made visible or intelligible through this act) and that which remains invisible and secret by resisting a definitive translation, which, as such, requires further interpretations in search for intelligibility (or “visibility”). We analyze the extent to which such relation between the visible and the invisible takes part in the translation of the notion of blackness raised by Mullen’s poems and how her translated poetry dialogues with issues of reception in Brazilian culture.

Use of virtual labs for enhance student's procedimental ability.

This article presents some results of a study investigating the use of the simulator VLAB, developed by Carnegie Mellon University, to increase the capacity of graduate students in Chemistry in the preparation of experimental procedures. The activity was conducted in two stages, first the students were asked a manuscript describing in detail the procedure and equipment used in the technique of dissolution and delivering it to the teacher. Later in the computer lab, each student performed the same procedure using the simulator. The activity has been proposed to determine if there could be accuracy gains of the description of the process when performed by the simulator. One of the main positive aspects obtained using the simulator students was the recognition of error, important in that the great majority recognized omitted or confused any process step. This reflection showed the students that in addition to testing a procedure using the simulator facilitates the organization of thought and helps arrange it logically. With the use of simulators, students are encouraged to take risks, to explore, to experience a new way, and a real lab usually offers much less room for risk, exploitation and failure.

Aeroelastic behavior of a wing with a magnetorheological hysteretic model to the damping

This paper shows the application of a hysteretic model for the Magnetorheological Damper (MRD) placed in the plunge degree-of-freedom of aeroelastic model of a wing. This hysteretic MRD model was developed by the researchers of the French Aerospace Lab. (ONERA) and describe, with a very good precision, the hysteretic behavior of the MRD. The aeroelastic model used in this paper do not have structural nonlinearities, the only nonlinearities showed in the model, are in the unsteady flow equations and are the same proposed by Theodorsen and Wagner in their unsteady aerodynamics theory; and the nonlinearity introduced by the hysteretic model used. The main objective of this paper is show the mathematical modeling of the problem and the equations that describes the aeroelastic response of our problem; and the gain obtained with the introduction of this hysteretic model in the equations with respect to other models that do not show the this behavior, through of pictures that represents the time response and Phase diagrams. These pictures are obtained using flow velocities before and after the flutter velocity. Finally, an open-loop control was made to show the effect of the MRD in the aeroelastic behavior.