Analysis of teaching experience based on teaching by the case method. Application to reinforcing wooden floors

The technique of reinforcement of wooden floors is a matter clearly multidisciplinary. The teaching of the subject using the "traditional" method, explaining the theory first and then proposing and solving problems has not been successful. This paper discusses the results of a teaching experiencie. It has been the teaching of the subject by the case method. The results are clearly superior to those obtained with the traditional methodology.

Steady state analysis of a storage integrated solar thermophotovoltaic (SISTPV) system

This paper presents the theoretical analysis of a storage integrated solar thermophotovoltaic (SISTPV) system operating in steady state. These systems combine thermophotovoltaic (TPV) technology and high temperature thermal storage phase-change materials (PCM) in the same unit, providing a great potential in terms of efficiency, cost reduction and storage energy density. The main attraction in the proposed system is its simplicity and modularity compared to conventional Concentrated Solar Power (CSP) technologies. This is mainly due to the absence of moving parts. In this paper we analyze the use of Silicon as the phase change material (PCM). Silicon is an excellent candidate because of its high melting point (1680 K) and its very high latent heat of fusion of 1800 kJ/kg, which is about ten times greater than the conventional PCMs like molten salts. For a simple system configuration, we have demonstrated that overall conversion efficiencies up to ?35% are approachable. Although higher efficiencies are expected by incorporating more advanced devices like multijunction TPV cells, narrow band selective emitters or adopting near-field TPV configurations as well as by enhancing the convective/conductive heat transfer within the PCM. In this paper, we also discuss about the optimum system configurations and provide the general guidelines for designing these systems. Preliminary estimates of night time operations indicate it is possible to achieve over 10 h of operation with a relatively small quantity of Silicon.

Annual report of the Secretary of the State Board of Agriculture of the State of Michigan ...

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Annual report ... / [State Board of Agriculture].

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Annual report of the Secretary of the State Board of Agriculture of the State of Michigan ...

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O PERFIL PROFISSIONAL DO SUPERVISOR DE ENSINO

Numa perspectiva sociológica, este trabalho tem o objetivo de identificar o perfil profissional do supervisor de ensino que atua na Secretaria de Estado da Educação de São Paulo, verificando se sua atuação está voltada ao pedagógico ou ao administrativo e qual o compromisso político e as concepções educacionais destes profissionais. Apoiando-se em Tragtenberg, Silva Jr e Huert, entre outros autores que abordam, especificamente, a supervisão de ensino, procurou-se fazer uma analise histórica da legislação, de planilhas e dos dados que foram colhidos através de depoimentos e entrevistas com supervisores de ensino efetivos de três Diretorias de Ensino da Grande São Paulo. O resultado da pesquisa aponta para a predominância de um perfil burocrático e de fiscalização na ação do supervisor de ensino, bem como de executor das políticas públicas e não partícipe da sua elaboração. O supervisor de ensino é um representante de um poder político que favorece uma determinada ordem, mesmo que exista uma tentativa de superação de uma representatividade unilateral dentro da supervisão de ensino.(AU)

O PERFIL PROFISSIONAL DO SUPERVISOR DE ENSINO

Numa perspectiva sociológica, este trabalho tem o objetivo de identificar o perfil profissional do supervisor de ensino que atua na Secretaria de Estado da Educação de São Paulo, verificando se sua atuação está voltada ao pedagógico ou ao administrativo e qual o compromisso político e as concepções educacionais destes profissionais. Apoiando-se em Tragtenberg, Silva Jr e Huert, entre outros autores que abordam, especificamente, a supervisão de ensino, procurou-se fazer uma analise histórica da legislação, de planilhas e dos dados que foram colhidos através de depoimentos e entrevistas com supervisores de ensino efetivos de três Diretorias de Ensino da Grande São Paulo. O resultado da pesquisa aponta para a predominância de um perfil burocrático e de fiscalização na ação do supervisor de ensino, bem como de executor das políticas públicas e não partícipe da sua elaboração. O supervisor de ensino é um representante de um poder político que favorece uma determinada ordem, mesmo que exista uma tentativa de superação de uma representatividade unilateral dentro da supervisão de ensino.(AU)

Yeast chorismate mutase in the R state: Simulations of the active site

The isomerization of chorismate to prephenate by chorismate mutase in the biosynthetic pathway that forms Tyr and Phe involves C5—O (ether) bond cleavage and C1—C9 bond formation in a Claisen rearrangement. Development of negative charge on the ether oxygen, stabilized by Lys-168 and Glu-246, is inferred from the structure of a complex with a transition state analogue (TSA) and from the pH-rate profile of the enzyme and the E246Q mutant. These studies imply a protonated Glu-246 well above pH 7. Here, several 500-ps molecular dynamics simulations test the stability of enzyme–TSA complexes by using a solvated system with stochastic boundary conditions. The simulated systems are (i) protonated Glu-246 (stable), (ii) deprotonated Glu-246 (unstable), (iii) deprotonated Glu-246 plus one H2O between Glu-246 and the ether oxygen (unstable), (iv) the E246Q mutant (stable), and (v) addition of OH− between protonated Glu-246 and the ether oxygen. In (v), a local conformational change of Lys-168 displaced the OH− into the solvent region, suggesting a possible rate-determining step that precedes the catalytic step. In a 500-ps simulation of the enzyme complexed with the reactant chorismate or the product prephenate, no water molecule remained near the oxygen of the ligand. Calculations using the linearized Poisson–Boltzmann equation show that the effective pKa of Glu-246 is shifted from 5.8 to 8.1 as the negative charge on the ether oxygen of the TSA is changed from −0.56 electron to −0.9 electron. Altogether, these results support retention of a proton on Glu-246 to high pH and the absence of a water molecule in the catalytic steps.

Chronic, topical exposure to benzo[a]pyrene induces relatively high steady-state levels of DNA adducts in target tissues and alters kinetics of adduct loss.

Carcinogen-DNA adduct measurements may become useful biomarkers of effective dose and/or early effect. However, validation of this biomarker is required at several levels to ensure that human exposure and response are accurately reflected. Important in this regard is an understanding of the relative biomarker levels in target and nontarget organs and the response of the biomarker under the chronic, low-dose conditions to which humans are exposed. We studied the differences between single and chronic topical application of benzo[a]pyrene (BAP) on the accumulation and removal of BAP-DNA adducts in skin, lung, and liver. Animals were treated with BAP at 10, 25, or 50 nMol topically once or twice per week for as long as 15 weeks. Animals were sacrificed either at 24, 48, or 72 hr after the last dose at 1 and 30 treatments, and after 24 hr for all other treatment groups. Adduct levels increased with increasing dose, but the slope of the dose-response was different in each organ. At low doses, accumulation was linear in skin and lung, but at high doses the adduct levels in the lung increased dramatically at the same time when the levels in the skin reached apparent steady state. In the liver adduct, levels were lower than in target tissues and apparent steady-state adduct levels were reached rapidly, the maxima being independent of dose, suggesting that activating metabolism was saturated in this organ. Removal of adducts from skin, the target organ, was more rapid following single treatment than with chronic exposure. This finding is consistent with earlier data, indicating that some areas of the genome are more resistant to repair. Thus, repeated exposure and repair cycles would be more likely to cause an increase in the proportion of carcinogen-DNA adducts in repair-resistant areas of the genome. These findings indicate that single-dose experiments may underestimate the potential for carcinogenicity for compounds that follow this pattern.