Mercado de Trabalho em Educação Física: significado da intervenção profissional em academia de ginástica

: Although the production of knowledge in the area has risen substantially, there is still a gap concerning the investigation about the relation of the Physical Education professional and the job market. Aiming to widen the understanding of the topic, we have defined the following targets: a) to discuss the professional intervention in a fitness center; and b) to analyze the meaning of such intervention for the professionals. Methodologically, this essay is characterized as a qualitative research and a case study. Physical Education professionals, who work in a large fitness center, have been interviewed. In the course of the transition and the implantation of an Intervention Standardized Program, that, which could be considered as a resistance to the changes, is, in fact, the affirmation made by the individuals of their condition as professionals. The subjects ( professionals) are aware that their intervention is measured by the knowledge acquired in their academic and professional experiences and by the knowledge which restrict this intervention.Embora a produção de conhecimento na área tenha crescido substancialmente, no que concerne à investigação sobre a relação do profissional de Educação Física e o mundo do trabalho ainda há uma lacuna. Visando ampliar o entendimento do tema definimos os seguintes objetivos: a) discutir a intervenção profissional em uma academia de ginástica; e b) analisar o significado da intervenção para os profissionais. Metodologicamente este trabalho caracteriza-se como uma pesquisa qualitativa e por um estudo de caso. Foram entrevistados profissionais de Educação Física que trabalham em uma grande academia. Em meio à transição e à implantação de um Programa Padronizado de Intervenção, aquilo que poderia ser considerado resistência às mudanças é, na verdade, a afirmação, feita pelos sujeitos, de sua condição de profissionais. Os sujeitos têm a consciência de que sua intervenção é mediada pelo conhecimento adquirido em suas experiências acadêmicas e profissionais e pelos saberes que delimitam essa intervenção

Structural variation, π-charge transfer, and transmission of electronic substituent effects in (E)-β-substituted styrenes: a quantum chemical study

The nature and transmission mechanism of substituent effects in (E)-β-substituted styrenes, C6H5-CH=CH-X, have been investigated from the structural changes induced by a variable substituent on the phenyl group. The molecular structures of 46 (E)-β-substituted styrenes were determined from MO calculations at the B3LYP/6-311++Glevel of theory. The structural variation of the phenyl probe is best represented by two orthogonal linear combinations of the internal ring angles, S F STY and S R STY. Regression analysis of S F STY using appropriate explanatory variables reveals a composite field effect, the main component of which originates from the long-range effect of the substituent enhanced by field-induced π-polarization of the vinylene spacer and resonance-induced field effects. The electronegativity of the substituent also plays a role in determining the value of S F STY. Comparison with coplanar 4-substituted biphenyls reveals that the components of the field effect in the two molecular systems are of the same nature (apart from the electronegativity contribution, which is not present in biphenyl derivatives). However, the structural variation of the phenyl probe is more pronounced in (E)-β-substituted styrenes due to the shorter distance between substituent and probe. Analysis of π-charge distribution shows that the aptitude of the substituents to exchange π-electrons with the styrene and coplanar biphenyl frames is nearly the same. Nevertheless, the π-charge variation on the phenyl probe of (E)-β-substituted styrenes is 57 % greater than the corresponding quantity in coplanar 4-substituted biphenyls. Thus, the vinylene spacer is more effective than the phenylene spacer in transmitting π-charges. The S R STY parameter is related to the amount of π-charge transferred from the -CH=CH-X moiety into the π-system of the benzene ring, or vice versa, due to the resonance effect of the variable substituent and, to a lesser extent, to field-induced π-polarization. © 2013 Springer Science+Business Media New York

Structural variation, π-charge transfer, and transmission of electronic substituent effects through the carbon-carbon triple bond in β-substituted phenylacetylenes: a quantum chemical study, and a comparison with (E)-β-substituted styrenes

The transmission of electronic substituent effects through a carbon-carbon triple bond has been investigated from the small changes induced by a variable substituent X on the geometry of the phenyl group in β-substituted phenylacetylenes, Ph−C≡C−X. The geometries of many such molecules were determined by quantum chemical calculations at the B3LYP/6-311++G** level of theory. The structural variation of the phenyl probe is best represented by a linear combination of the internal ring angles, termed SFPHA. Multiple regression analysis of SFPHA using appropriate explanatory variables reveals a composite polar effect. The main components are, in order of decreasing importance: (i) the field effect of the substituent, enhanced by field-induced π-polarization of the −C≡C− spacer, (ii) the resonance-induced field effect, and (iii) the electronegativity effect. These results are compared with those obtained for (E)-β-substituted styrenes, Ph−CH=CH−X, using the same statistical technique, applied to a structural parameter termed SFSTY. The comparison shows that in β-substituted phenylacetylenes, the field effect of the substituent plays a more important role, and the resonance effect a less important, than in (E)-β-substituted styrenes. This is a consequence of the greater polarizability of the C≡C bond as compared with the C=C bond. The role played by the electronegativity of the substituent is the same for the two sets of molecules. A peculiar feature of the −C≡C− spacer is that its π-system consists of two separate parts, corresponding to the two π-bonds that concur to the formation of the triple bond. Only the part orthogonal to the plane of the phenyl probe may interact with the probe π-system, making it possible to transfer π-electron density from substituent to probe, or vice versa. The part coplanar with the phenyl probe may exchange π-electron density with the substituent, but not with the probe. Thus, π-interactions between substituent, spacer, and probe depend critically on the electronic structure and conformation of the substituent. We have classified the substituents in three categories according to the different types of π-interactions that occur in β-substituted phenylacetylenes. First category substituents exchange π-electron density with the orthogonal part of the π-system of the spacer, and hence with the π-system of the probe. While the orthogonal part of the π-system of the spacer acts as a π-electron channel, the coplanar part cannot exchange electrons with the π-system of the phenyl probe. With second category substituents, the conformation of the molecule inhibits the exchange of π-electron density between substituent and probe. The substituent can only exchange π-electrons with the part of the π-system of the spacer that is coplanar with the phenyl probe. Third category substituents exchange π-electron density with both parts of the π-system of the spacer. While the π-charge transferred into the orthogonal part can be further delocalized into the π-system of the phenyl probe, the π-charge transferred into the coplanar part cannot and remains blocked in the spacer. From there, however, it gives rise to an inductive effect that polarizes the π-electron system of the phenyl probe. The π-charge distribution in 45 β-substituted phenylacetylenes and the corresponding(E)-β-substituted styrenes has been determined by Natural Atomic Orbital analysis at the B3LYP/6-311++G** level of theory. The results of the analysis support our classification of the substituents in three categories and reveal the existence of a number of important correlations involving charges as well as structural parameters