Correspondence between the one-loop three-point vertex and the Y and Delta electric resistor networks

Different mathematical methods have been applied to obtain the analytic result for the massless triangle Feynman diagram yielding a sum of four linearly independent (LI) hypergeometric functions of two variables F-4. This result is not physically acceptable when it is embedded in higher loops, because all four hypergeometric functions in the triangle result have the same region of convergence and further integration means going outside those regions of convergence. We could go outside those regions by using the well-known analytic continuation formulas obeyed by the F-4, but there are at least two ways we can do this. Which is the correct one? Whichever continuation one uses, it reduces a number of F-4 from four to three. This reduction in the number of hypergeometric functions can be understood by taking into account the fundamental physical constraint imposed by the conservation of momenta flowing along the three legs of the diagram. With this, the number of overall LI functions that enter the most general solution must reduce accordingly. It remains to determine which set of three LI solutions needs to be taken. To determine the exact structure and content of the analytic solution for the three-point function that can be embedded in higher loops, we use the analogy that exists between Feynman diagrams and electric circuit networks, in which the electric current flowing in the network plays the role of the momentum flowing in the lines of a Feynman diagram. This analogy is employed to define exactly which three out of the four hypergeometric functions are relevant to the analytic solution for the Feynman diagram. The analogy is built based on the equivalence between electric resistance circuit networks of types Y and Delta in which flows a conserved current. The equivalence is established via the theorem of minimum energy dissipation within circuits having these structures.

Equivalence between the application of entransy and entropy generation

Recently, a group of researchers proposed the concept of entransy by analogy with the electrical energy stored in a capacitor, the entransy being a measure of the ability of a body or a system to transfer heat. In comparative terms, the entransy dissipation rate is related with the loss of heat transfer ability just like the exergy destruction rate is proportional to the loss of work ability, being these losses caused by the irreversibilities related to the thermodynamic processes. Some authors have questioned the need for the concept of entransy, claiming that this concept is only an extension of a well established theory of heat transfer. The objective of this work is show the equivalence between the application of the concepts of entransy and entropy generation rate, which can be verified using various application examples. The application examples used here are the thermodynamic modeling of three physical models of solar energy collectors and a physical model of a sensible heat storage system. Analytical results are shown and compared. The results showed that the application of the concept of entransy provided identical expressions obtained by the concept of entropy generation, indicating a duplication of concepts. (C) 2014 Elsevier Ltd. All rights reserved.

José Feliciano de Castilho e a tradição clássica do séc. XIX: memória sobre a segunda égloga de Virgílio

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Classification of intact fresh plums according to sweetness using time-domain nuclear magnetic resonance and chemometrics

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Emissões de poluentes em centrais hidrelétricas: aspectos técnicos, econômicos e ecológicos

Pós-graduação em Engenharia Mecânica - FEG

Effect of two formulations of 10% sodium ascorbate on fracture resistance of endodontically treated tooth submitted to dental bleaching with hydrogen peroxide associated titanium dioxide nanoparticles

Purpose: This study evaluated the effect of 10% sodium ascorbate (10SA), in gel (10SAg) or aqueous solution (10SAs) formulations, on fracture resistance of endodontically treated tooth submitted to dental bleaching procedures with 15% hydrogen peroxide associated with titanium dioxide (15HP-TiO2) nanoparticles and photoactivated by LED-laser. Material and methods: Forty maxillary premolars were endodontically-treated and embedded in acrylic resin up to the cement-enamel junction. The specimens were divided into four groups (n=10): G1 (negative control): no bleaching, coronal access restored with composite resin; G2 (positive control): three dental bleaching sessions using 15HP-TiO2 and LED-laser photoactivation and restored with composite resin (positive control); G3 (10SAg): similar procedures to G2, but applied 10SA, in gel formulation, for 24 hours before restoration; G4 (10SAs): similar procedures to G3, but applied 10SA, in aqueous solution formulation. The 15HP-TiO2 was applied on buccal and lingual surfaces of the crown tooth and inside the pulp chamber and photoactivated by LED-laser. Between each bleaching session, the teeth were maintained in artificial saliva, at 37oC, for 7 days. In sequence, the teeth were submitted to fracture resistance testing using an eletromechanical machine test. The data was analyzed using Kruskal Wallis test (p = 0.05) Results: There are no differences significant among the groups in relation to fracture resistance of endodontically treated teeth (p>0.05). Conclusions: The use of 10% sodium ascorbate, in gel or aqueous solution formulations, did not interfered on the fracture resistance teeth after dental bleaching using 15HP-TiO2 and LED-laser photoactivation.

Fracture resistance of teeth submitted to several internal bleaching protocols

Aim: The aim of this study was to evaluate the fracture resistance of teeth submitted to several internal bleaching protocols using 35% hydrogen peroxide (35HP), 37% carbamide peroxide (37CP), 15% hydrogen peroxide with titanium dioxide nanoparticles (15HPTiO2) photoactivated by LED-laser or sodium perborate (SP). Materials and methods: After endodontic treatment, fifty bovine extracted teeth were divided into five groups (n = 10): G1-unbleached; G2-35HP; G3-37CP; G4-15HPTiO2 photoactivated by LED-laser and G5-SP. In the G2 and G4, the bleaching protocol was applied in 4 sessions, with 7 days intervals between each session. In the G3 and G5, the materials were kept in the pulp teeth for 21 days, but replaced every 7 days. After 21 days, the teeth were subjected to compressive load at a cross head speed of 0.5 mm/min, applied at 135° to the long axis of the root using an eletromechanical testing machine, until teeth fracture. The data were submitted to ANOVA and Tukey tests (α = 5%). Results: The 35HP, 37CP, 15HPTiO2 and SP showed similar fracture resistance teeth reduction (p > 0.05). All bleaching treatments reduced the fracture resistance compared to unbleached teeth (p < 0.05). Conclusion: All bleaching protocols reduced the fracture resistance of endodontically-treated teeth, but there were no differences between each other. Clinical significance: There are several internal bleaching protocols using hydrogen peroxide in different concentrations and activation methods. This study evaluated its effects on fracture resistance in endodontically-treated teeth.

Fracture resistance of endodontically-treated teeth submitted to bleaching treatment with hydrogen peroxide and titanium dioxide nanoparticles photoactivated by LED-laser

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A matemática e o GPS

Pós-graduação em Matemática - IBILCE

De Hegel a Marx: da inflexão ontológica à antítese direta

We will deal with the Marxian criticism to the Hegelian notion of "being". it will be shown that historicity and objectivity are determinations of this category (and that categories are always.,forms of being, determinations of existence). So, the analogy between the Hegelian logic and the Marxian theory may sometimes, hide essential aspects of the materialist comprehension of history Here, we intend to prove that, by questioning the treatment dispensed to the matter of being by Hegel, Marx criticizes the Hegelian inversion between subject and predicate in a way that, although dialoguing with Hegel, his conception is the exact opposite at the same time.

Challenges in the therapy of visceral leishmaniasis in Brazil: a public health perspective

Over 3,000 yearly cases of Visceral Leishmaniasis (VL) are reported in Brazil. Brazilian Public Health System provides universal free access to antileishmania therapeutic options: Meglumine Antimoniate, Amphotericin B deoxycholate, and Liposomal Amphotericin B. Even though Amphotericin formulations have been advised for severe disease, this recommendation is mostly based on the opinion of experts and on analogy with studies conducted in other countries. Presently, there are two ongoing multicenter clinical trials comparing the efficacy and safety of the available therapeutic options. Some other issues require further clarification, such as severity markers and the approach to VL/AIDS coinfection. Brazil is facing the challenge of providing access to diagnosis and adequate treatment, in order to avoid VL-related deaths.

Jogo digital e analogias: uma proposta para o ensino de Cinética Química

Pós-graduação em Educação para a Ciência - FC

O esquecido de si, Dante Milano: rastros de uma poética do esquecimento

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Uma descrição semiótica da metáfora no ensino de biologia: asserções sobre a célula animal

The main objective of this survey is describing signly the metaphor learning resource, with focus on biology education. Our teorical reference is the peircean semiotics, because it means solid heritage to code surveys implicated at science education, it led us to do an explanation about the main lines about that reference, addressed to researchers and lecturers interested in those reasonings. In the description yearned, another objectives appear: demonstrate diferences between metaphor/analogy and pragmatic analogy; to list metaphors, from cell representation analysis, and argue about principals diferences and probable cognitive consequences between the metaphor event in the visual representation and speech sentences. Therefore we analysed the animal cell of a high school first grade studying book – biology – cell biology – used by São Paulo and another state students. The findings demonstrate the undeniable importance of the metaphor as a learning tool in the biology education, and new findings about that, such as its limits in the concept elaboration, gnosiologic consequences for receptioning, the search needs for propositions– pictures between concept relations – in the science speech construction, and other results.

O design no contexto histórico da arte: uma visão da arte e do design a partir do ornamento

Drawing an equivalence analogy between the subjects of style and the ornamentation, the study leans on Aloïs Riegl's theory in order to sketch an anthropological reflection for the appearance of the design and some of their respective confluences with the art. Enriched by the progresses that the psychology of the visual perception provided to the contemporary understanding for the artistic representation, and consequently of this historicity, breaks of the hypothesis that this appearance has given in a process naturally evolutionary, aiming at to supply an inherent human need.