Whole-body cortisol increases after direct and visual contact with a predator in zebrafish, Danio rerio

Ornamental fish may be severely affected by a stressful environment. Stressors impair the immune response, reproduction and growth rate; thus, the identification of possible stressors will aid to improve the overall quality of ornamental fish. The aim of this study was to determine whole-body cortisol of adult zebrafish, Danio rerio, following visual or direct contact with a predator species. Zebrafish were distributed in three groups: the first group, which consisted of zebrafish reared completely isolated of the predator, was considered the negative control; the second group, in which the predator, Parachromis managuensis was stocked together with zebrafish, was considered the positive control; the third group consisted of zebrafish stocked in a glass aquarium, with direct visual contact with the predator. The mean whole-body cortisol concentration in zebrafish from the negative control was 6.78 +/- 1.12 ng g(-1), a concentration statistically lower than that found in zebrafish having visual contact with the predator (9.26 +/- 0.88 ng g(-1)) which, in turn, was statistically lower than the mean whole-body cortisol of the positive control group (12.35 +/- 1.59 ng g(-1)). The higher whole-body cortisol concentration found in fish from the positive control can be attributed to the detection, by the zebrafish, of relevant risk situations that may involve a combination of chemical, olfactory and visual cues. One of the functions of elevated cortisol is to mobilize energy from body resources to cope with stress. The elevation of whole-body cortisol in fish subjected to visual contact with the predator involves only the visual cue in the recognition of predation risk. We hypothesized that the zebrafish could recognize predator characteristics in P managuensis, such as length, shape, color and behavior. Nonetheless, the elevation of whole-body cortisol in zebrafish suggested that the visual contact of the predator may elicit a stress response in prey fish. This assertion has a strong practical application concerning the species distribution in ornamental fish markets in which prey species should not be allowed to see predator species. Minimizing visual contact between prey and predator fish may improve the quality, viability and welfare of small fish in ornamental fish markets. (c) 2007 Elsevier B.V. All rights reserved.

Tunable visible photoluminescence of powdered silica glass

intense photoluminescence in the visible region was observed at room temperature in standard soda-lime-silica glass powder, mechanically milled in a high-energy attrition mill. The emission band maximum shows an interesting dependence on the exciting wavelength, suggesting the possibility to tune the PL emission. These findings indicate that the photoluminescence may be directly related to unsatisfied chemical bonds correlated with the high surface area. The Raman scattering and ultraviolet-visible optical reflectance measurements corroborate this assertion. Transmission electron microscopy measurements indicate that samples milled more than 10 h present the formation of nanocrystallites with about 10-20 nm. (C) 2007 Elsevier B.V. All rights reserved.

An overview of biodiesel soil pollution: Data based on cytotoxicity and genotoxicity assessments

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

Para que serve uma subjetividade? Foucault, tempo e corpo

O presente artigo procura retomar a mudança de rumo da obra de Foucault que determinou o enfoque sobre a subjetividade, sobretudo nos dois últimos volumes de História da Sexualidade. Com isso, nossa atenção volta-se para os marcos da definição de subjetividade como processo ou prática, que são a relação com o tempo e a dimensão transformacional ou criativa do corpo. Tal investigação conceitual sobre a subjetividade em Foucault procura indicar, outrossim, de que maneira a criação filosófica está relacionada ao modo de vida ou estilo de um filósofo. O pensamento derradeiro de Foucault é consistente com o estilo que ele vinha construindo no decorrer de sua obra, de modo que se discute a invectiva de que esta última fase, por razões várias, seria o lugar de um retorno do sujeito ou do homem que Foucault havia negado anteriormente.

Traços de personalidade e habilidades sociais em universitários

O presente estudo teve como objetivo analisar as relações entre habilidades sociais e traços de personalidade englobados por socialização, no modelo dos Cinco Grandes Fatores. O Inventário de Habilidades Sociais (IHS) foi utilizado para a mensuração de habilidades sociais, e para avaliação do nível de socialização foi escolhida a Escala Fatorial de Socialização (EFS). A amostra foi composta por 126 estudantes universitários com média de idade de 21 anos (DP=3,37), e 53,5% eram homens. Os resultados da IHS e EFS foram comparados para os sexos, encontrando-se diferenças estatisticamente significativas para seis das dez medidas realizadas no estudo. Foram encontradas correlações significativas entre amabilidade, auto-afirmação e o total do IHS. Pró-sociabilidade correlacionou-se com auto-afirmação e autocontrole. Confiança nas pessoas apresentou correlações significativas com enfrentamento, auto-afirmação e autocontrole. Os resultados indicam que, efetivamente, a personalidade pode influenciar diferentes aspectos da habilidade social.

Dissipative three-wave structures in stimulated backscattering. I. A subluminous solitary attractor

We present a solitary solution of the three-wave nonlinear partial differential equation (PDE) model - governing resonant space-time stimulated Brillouin or Raman backscattering - in the presence of a cw pump and dissipative material and Stokes waves. The study is motivated by pulse formation in optical fiber experiments. As a result of the instability any initial bounded Stokes signal is amplified and evolves to a subluminous backscattered Stokes pulse whose shape and velocity are uniquely determined by the damping coefficients and the cw-pump level. This asymptotically stable solitary three-wave structure is an attractor for any initial conditions in a compact support, in contrast to the known superluminous dissipative soliton solution which calls for an unbounded support. The linear asymptotic theory based on the Kolmogorov-Petrovskii-Piskunov assertion allows us to determine analytically the wave-front slope and the subluminous velocity, which are in remarkable agreement with the numerical computation of the nonlinear PDE model when the dynamics attains the asymptotic steady regime. © 1997 The American Physical Society.

Diagnostic de securite d'une entreprise bresilienne a partir de l'analyse des accidents du travail par la methode de l'arbre des causes

We present here the results of a study of 21 work-related accidents that occurred in a Brazilian manufacturing company. The aim was to assess the safety level of the company to improve its work accident prevention policy. In the last 6 months of 1992 and 1993, all accidents resulting in 15 days' absence from work, reported for social security purposes, were analyzed using the INRS causal tree method (ADC) and a questionnaire completed on site. Potential risk factors for accidents were identified based on the specific factors highlighted by the ADC. More universal trees were also compiled for the safety assessment. Three hundred and thirty specific accident factors were recorded (man of 15.71 per accident). This is consistent with there being multiple causes of accidents rather than the assertion of Brazilian business safety departments that accidents are due to 'dangerous' or 'unsafe' behavior. Introducing the idea of culpability into accidents prevents the implementation of an appropriate information feedback process, essential for effective prevention. However, the large number of accidents related to 'material' (78%) and 'environment' (70%) indicates that working conditions are poor. This shows that the technical risks, mostly due to unsafe machinery and equipment are not being dealt with. Seventy-five potential accident factors were identified. Of these, 35% were 'organizational', a high proportion for the company studied. Improvisation occurs at all levels, particularly at the organizational level. This is, thus a major determinant for entire series of, if not most, accident situations. The poor condition of equipment also plays a major role in accidents. The effects of poor equipment on safety exacerbate the organizational shortcomings. The company's safety intervention policy should improve the management of human resources (rules designating particular workers for particular workstations; instructions for the safe operation of machines and equipment; training of operators, etc.) and introduce programs to detect risks and to improve the safety of machines and equipment. We also recommend the establishment of a program to follow the results of any preventive measures adopted.

Diagnostic de sécurité d’une entreprise brésilienne à partir de l’analyse des accidents du travail par la méthode de l’arbre des causes

We present here the results of a study of 21 work-related accidents that occurred in a Brazilian manufacturing company. The aim was to assess the safety level of the company to improve its work accident prevention policy. In the last 6 months of 1992 and 1993, all accidents resulting in 15 days' absence from work, reported for social security purposes, were analyzed using the INRS causal tree method (ADC) and a questionnaire completed on site. Potential risk factors for accidents were identified based on the specific factors highlighted by the ADC. More universal trees were also compiled for the safety assessment. Three hundred and thirty specific accident factors were recorded (mean of 15.71 per accident). This is consistent with there being multiple causes of accidents rather than the assertion of Brazilian business safety departments that accidents are due to dangerous or unsafe behavior. Introducing the idea of culpability into accidents prevents the implementation of an appropriate information feedback process, essential for effective prevention. However, the large number of accidents related to material (78%) and environment (70%) indicates that working conditions are poor. This shows that the technical risks, mostly due to unsafe machinery and equipment are not being dealt with. Seventy-five potential accident factors were identified. Of these, 35% were organizational, a high proportion for the company studied. Improvisation occurs at all levels, particularly at the organizational level. This is thus a major determinant for entire series of, if not most, accident situations. The poor condition of equipment also plays a major role in accidents. The effects of poor equipment on safety exacerbate the organizational shortcomings. The company's safety intervention policy should improve the management of human resources (rules designating particular workers for particular workstations; instructions for the safe operation of machines and equipment; training of operators, etc.) and introduce programs to detect risks and to improve the safety of machines and equipment. We also recommend the establishment of a program to follow the results of any preventive measures adopted.

New remarks on the linear constraint self-dual boson and Wess-Zumino terms

In this work we prove in a precise way that the soldering formalism can be applied to the Srivastava chiral boson (SCB), in contradiction with some results appearing in the literature. We promote a canonical transformation that shows directly that the SCB is composed of two Floreanini-Jackiw particles with the same chirality in which the spectrum is a vacuumlike one. As another conflicting result, we prove that a Wess-Zumino (WZ) term used in the literature consists of a scalar field, once again denying the assertion that the WZ term adds a new degree of freedom to the SCB theory in order to modify the physics of the system. © 2001 The American Physical Society.

A amizade como paisagem conceitual e o amigo como personagem conceitual, segundo deleuze e guattari

This paper begins with the Proposal of a pedagogy of concept according to Deleuze and Guattari. On this basis, I emphasize and explore the assertion that every thought demands relational traces as their internal condition. Among the relational traces defined by this pedagogy of concept, I selected friend as a character who distinguishes a given thought. I try, after that, to define, generally what friend and the scene of friendship in Plato's, Nietzsche's, Heidegger's and Foucault's philosophies are.

Defect-induced photoluminescence of powdered silica glass

Visible photoluminescence was generated in standard soda-lime-silica glass powder, mechanically milled in a high-energy attrition mill. The broad emission band maximum shows a linear dependence on the exciting wavelength, suggesting the possibility to tune the PL emission. The photoluminescence was attributed to defect generation related to unsatisfied chemical bonds due to the high surface area. Raman scattering and ultraviolet-visible optical reflectance measurements corroborate this assertion. Transmission electron microscopy measurements indicate that the powder is composed by nanocrystallites with about 10-20 nanometers immersed in an amorphous media.

Potencial imunogênico dos curativos bioativos: aspectos imunhematológicos e leucoplaquetários

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ensino médio e interdisciplinaridade: um estudo sobre o conceito de efeito estufa

Pós-graduação em Educação para a Ciência - FC

Insultos e afagos: Silvio Romero e os debates de seu tempo

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

O governo Bernardes e a Liga das Nações

Pós-graduação em História - FCHS