The effect of alcohol and drug consumption on academic performance : a treatment effect evaluation

It is often argued that consumption of alcohol, tobacco and drugs is detrimental to the cognitive abilities of teenagers. In order to disentangle a possible causal effect of these substances use from a self-selection bias, we control for pupils previous performance and for their previous rate of progression applying a DiDiD strategy. Using the NELS 1988 panel dataset, we find that the effects of alcohol and tobacco on test scores disappear once the selection bias is controlled for (this does not preclude long term detrimental effects). However, we find reliable evidence that heavy use of drugs (marijuana and cocaine) has direct detrimental effects on educational achievements. Hence, our results may have significant policy implications.

Higher salaries, more teaching, better performance? The effects of the introduction of the minimum salary for teachers in Brazil

De acordo com a literatura empírica, há fortes evidências de que, após o controle de características socioeconômicas dos alunos, a qualidade dos professores é o fator mais importante para explicar o desempenho do aluno em testes padronizados. No entanto, não há consenso sobre como sistemas públicos de ensino podem melhorar a qualidade dos professores. Será que o pagamento de salários mais elevados a professores da rede pública impactam a qualidade dos professores nas escolas públicas? O Governo Federal brasileiro introduziu, em 2009, piso salarial nacional para os professores de escolas públicas, provocando um perceptível aumento exógeno dos salários dos professores municipais. O principal objetivo desta tese é avaliar os impactos de curto prazo da elevação linear e incondicional do salário do professor na qualidade da educação. Devido à ausência de dados secundários sobre o valor do salário-base de professores entre 2008 e 2013, tivemos que realizar um levantamento com as Secretarias Municipais de Educação para reunir informação sobre a estrutura da carreira docente e sobre os salários-bases nesse período. Com base em nossa pesquisa de campo, o primeiro capítulo investiga a conformidade dos sistemas municipais de ensino ao piso salarial nacional para professores de redes públicas. Encontramos que fatores não observáveis/observados são determinantes para explicar a variabilidade salarial verificada entre os municípios e o cumprimento da lei, o que embasa nossa estratégia de identificação com base em métodos de diferença em diferenças, combinados com pareamento com base em escore de propensão. O segundo capítulo centra-se na estimativa do impacto da elevação dos salários dos professores sobre a proficiência dos alunos de 5º ano do ensino fundamental municipal. De acordo com estes resultados, o aumento salarial incondicional não gerou uma expansão da proficiência escolar dos alunos, pelo menos no curto prazo. Embora não tenham sido detectados impactos na aprendizagem dos alunos, alguns mecanismos de transmissão do aumento salarial para melhores resultados educacionais podem já ter sido ativados. Assim, o principal objetivo do terceiro capítulo é avaliar o impacto dos aumentos de salário sobre a qualidade dos professores atuais e dos potenciais futuros professores. Avaliamos o impacto de aumentos de salário sobre o desempenho dos professores no ENADE, uma proxy de sua qualidade, e sobre a atratividade dos cursos de ensino superior associados à carreira docente. Essa atratividade é medida por meio da qualidade dos que entram nos respectivos cursos superiores, de acordo com seu desempenho no Enem. Neste último capítulo, aplicamos modelo de Tripla-Diferenças visando controlar dois tipos de potenciais fatores de confusão: (i) mudanças no desempenho dos professores (potenciais futuros professores) entre grupos de municípios, que foram submetidos ao tratamento e os que não foram tratados, que nada têm a ver com a política; e (ii) as alterações no desempenho de todos os professores (alunos) que vivem no município em que houve a elevação salarial devido à introdução da lei. As estimativas obtidas indicam que a elevação salarial gerou efeitos leves sobre a qualidade dos professores e sobre a atratividade dos cursos relacionados à carreira docente.

Three Essays in Economics of Gender

During recent decades, economists' interest in gender-related issues has risen. Researchers aim to show how economic theory can be applied to gender related topics such as peer effect, labor market outcomes, and education. This dissertation aims to contribute to our understandings of the interaction, inequality and sources of differences across genders, and it consists of three empirical papers in the research area of gender economics. The aim of the first paper ("Separating gender composition effect from peer effects in education") is to demonstrate the importance of considering endogenous peer effects in order to identify gender composition effect. This fact is analytically illustrated by employing Manski's (1993) linear-in-means model. The paper derives an innovative solution to the simultaneous identification of endogenous and exogenous peer effects: gender composition effect of interest is estimated from auxiliary reduced-form estimates after identifying the endogenous peer effect by using Graham (2008) variance restriction method. The paper applies this methodology to two different data sets from American and Italian schools. The motivation of the second paper ("Gender differences in vulnerability to an economic crisis") is to analyze the different effect of recent economic crisis on the labor market outcome of men and women. Using triple differences method (before-after crisis, harder-milder hit sectors, men-women) the paper used British data at the occupation level and shows that men suffer more than women in terms of probability of losing their job. Several explanations for the findings are proposed. The third paper ("Gender gap in educational outcome") is concerned with a controversial academic debate on the existence, degree and origin of the gender gap in test scores. The existence of a gap both in mean scores and the variability around the mean is documented and analyzed. The origins of the gap are investigated by looking at wide range of possible explanations.

Fourier transform of the collagen triple-helical structure and its significance

The Fourier transforms of the collagen molecular structure have been calculated taking into consideration various side chain atoms, as well as the presence of bound water molecules. There is no significant change in the calculated intensity distribution on including the side chain atoms of non-imino-acid residues. Taking into account the presence of about two bound water molecules per tripeptide unit, the agreement with the observed x-ray pattern is slightly improved. Fourier transforms have also been calculated for the detailed molecular geometries proposed from other laboratories. It is found that there are no major differences between them, as compared to our structure, either in the positions of peak intensity or in the intensity distribution. Hence it is not possible to judge the relative merits of the various molecular geometries for the collagen triple helix from a comparison of the calculated transforms with the meagre data available from its x-ray fibre pattern. It is also concluded that the collagen molecular structure should be regarded as a somewhat flexible chain structure, capable of adapting itself to the requirements of the different side groups which occur in each local region.

Analysis of the energies of the triple base triplets

Sixty-four sets of three-dimensional models of DNA triplex base triplets (TBT) were built up based on codons by homologous modeling method and their energies were minimized. According to sequence of TBT and orientation of the third ODN strand third, the energies of monomers and water-K+-TBT ternary complexes of TBT were analyzed. The results showed: (i) The energies of the symmetric parallel monomers are generally lower than those of the symmetric anti-parallel monomers of TBT, but the energies of the symmetric parallel ternary complexes are higher than those of the symmetric anti-parallel ternary complexes of TBT. (ii) No matter TBTs are monomers or ternary complexes, the energies of asymmetric parallel TBTs are generally lower than those of the asymmetric anti-parallel ones. (iii) Although the energies of the parallel TBTs are correlated with those of the anti-parallel ones, the energy differences are significant between them. The results here suggest the sequences of TBTs and the orientations of the third ODN strands are two of the key factors that can influence the formation and stability of TBT. (C) 2002 Elsevier Science B.V. All rights reserved.

Primary relapse site pattern in women with triple-negative breast cancer

Despite the remarkable improvements in breast cancer (BC) characterization, accurate prediction of BC clinical behavior is often still difficult to achieve. Some studies have investigated the association between the molecular subtype, namely the basal-like BC and the pattern of relapse, however only few investigated the association between relapse pattern and immunohistochemical defined triple-negative breast cancers (TNBCs). The aim of this study was to evaluate the pattern of relapse in patients with TNBC, namely the primary distant relapse site:One-hundred twenty nine (129) invasive breast carcinomas with follow-up information were classified according to the molecular subtype using immunohistochemistry for ER, PgR and Her2. The association between TNBC and distant relapse primary site was analyzed by logistic regression. Using multivariate logistic regression analysis patients with TNBC displayed only 0.09(95% CI: 0.00-0.74; p = 0.02) the odds of, the non-TNBC patients of developing bone primary relapse. Regarding visceral and lymph-node relapse, no differences between in this cohort were found.Though classically regarded as aggressive tumors, TNBCs rarely development primary relapse in bone when compared to non-TNBC, a clinical relevant fact when investigating a metastasis of an occult or non-sampled primary BC. (C) 2014 Elsevier GmbH. All rights reserved.

Oxidative stress and inflammation response after nanoparticle exposure: differences between human lung cell monocultures and an advanced three-dimensional model of the human epithelial airways

Combustion-derived and manufactured nanoparticles (NPs) are known to provoke oxidative stress and inflammatory responses in human lung cells; therefore, they play an important role during the development of adverse health effects. As the lungs are composed of more than 40 different cell types, it is of particular interest to perform toxicological studies with co-cultures systems, rather than with monocultures of only one cell type, to gain a better understanding of complex cellular reactions upon exposure to toxic substances. Monocultures of A549 human epithelial lung cells, human monocyte-derived macrophages and monocyte-derived dendritic cells (MDDCs) as well as triple cell co-cultures consisting of all three cell types were exposed to combustion-derived NPs (diesel exhaust particles) and to manufactured NPs (titanium dioxide and single-walled carbon nanotubes). The penetration of particles into cells was analysed by transmission electron microscopy. The amount of intracellular reactive oxygen species (ROS), the total antioxidant capacity (TAC) and the production of tumour necrosis factor (TNF)-alpha and interleukin (IL)-8 were quantified. The results of the monocultures were summed with an adjustment for the number of each single cell type in the triple cell co-culture. All three particle types were found in all cell and culture types. The production of ROS was induced by all particle types in all cell cultures except in monocultures of MDDCs. The TAC and the (pro-)inflammatory reactions were not statistically significantly increased by particle exposure in any of the cell cultures. Interestingly, in the triple cell co-cultures, the TAC and IL-8 concentrations were lower and the TNF-alpha concentrations were higher than the expected values calculated from the monocultures. The interplay of different lung cell types seems to substantially modulate the oxidative stress and the inflammatory responses after NP exposure.

Molecular Dynamics Simulations of the d(TAT) Triple Helix

Molecular dynamics (MD) simulations have been used to study the dynamical and time-averaged characteristics of the DNA triple helix d(T)10âd(A)10âd(T)10. The structures sampled during the trajectory resemble closely the B-type model for the DNA triplex proposed on the basis of NMR data, although there are some subtle differences. Alternative P- and A-type conformations for the triplex, suggested from X-ray experiments, are not predicted to contribute significantly to the structure of the DNA triplex in solution. Comparison with the best available experimental data supports the correctnes of the MD-generated structures. The analysis of the collected data gives a detailed picture of the characteristics of triple-helix DNA. A new and interesting pattern of hydration, specific for triplex DNA, is an important observation. The results suggest that molecular dynamics can be useful for the study of novel nucleic acid structures.

A molecular anchor for stabilizing triple-helical DNA.

Molecular modeling has been used to predict that 2,6-disubstituted amidoanthraquinones, and not the 1,4 series, should preferentially interact with and stabilize triple-stranded DNA structures over duplex DNA. This is due to marked differences in the nature of chromophore-base stacking and groove accessibility for the two series. A DNA foot-printing method that monitors the extent of protection from DNase I cleavage on triplex formation has been used to examine the effects of a number of synthetic isomer compounds in the 1,4 and 2,6 series. The experimental results are in accord with the predicted behavior and confirm that the 1,4 series bind preferentially to double- rather than triple-stranded DNA, whereas the isomeric 2,6 derivatives markedly favor binding to triplex DNA.

Sistemas de gestão integrados como indutor para a sustentabilidade: uma análise do impacto no desempenho das organizações baseado no Triple Bottom Line.

O objetivo deste trabalho é analisar o impacto dos Sistemas de Gestão Integrados (SGI) no desempenho organizacional sob a óptica do Triple Bottom Line (TBL), verificando se esta implementação auxilia a empresa a se tornar mais sustentável. A abordagem multi-método utilizada está dividida em três partes. A primeira compreende uma revisão sistemática da literatura, tendo como base a abordagem bibliométrica. A base de dados escolhida para a seleção dos artigos que compõem a amostra foi a ISI Web of Knowledge (Web of Science). As análises conduzidas sugerem lacunas na literatura a serem pesquisadas de modo a relacionar a integração dos sistemas de gestão como meio para as organizações tornarem-se mais sustentáveis, auxiliando assim na elaboração de um modelo teórico e das hipóteses de pesquisa. Os resultados parciais obtidos ressaltam a lacuna na literatura de estudos nessa área, principalmente que contemplem a dimensão social do Triple Bottom Line. Lacunas na literatura foram identificadas também no que se refere à análise do impacto da adoção dessas abordagens normativas no desempenho organizacional. A segunda etapa da metodologia é composta por estudos de casos múltiplos em empresas de diferentes setores e que tenham implantado sistemas de gestão de maneira integrada. Os resultados obtidos mostram que a certificação auxilia no desenvolvimento de ações sustentáveis, resultando em impactos econômicos, ambientais e sociais positivos. Nesta etapa, testou-se o modelo e as hipóteses levantadas na abordagem bibliométrica. A terceira etapa da metodologia é composta por análises estatísticas de dados secundários extraídos da revista Exame ?Maiores e Melhores\'. Os dados do ano de 2014 das empresas foram tratados por meio do software MINITAB 17 ®. Por meio do teste de mediana de mood, as amostras foram testadas e apresentaram diferenças estatisticamente significativas para o desempenho das empresas em diferentes setores. De maneira geral, as empresas com SGI apresentam melhor desempenho econômico do que as demais. Com a mesma base de dados, utilizando o modelo de equações estruturais e o software Smart PLS 2.0, criou-se um diagrama de caminhos analisando os constructos (SGI) com variáveis de desempenho (Endividamento, Lucratividade, Patrimônio, Crescimento e Retorno). O modelo de equações estruturais testado apresentou força para a relação entre SGI com Endividamento, Lucratividade, Patrimônio e Crescimento. As diferentes metodologias apresentadas contribuíram para responder a hipótese e afirmar com base na amostra deste trabalho que o SGI leva as empresas a terem melhor desempenho econômico, ambiental e social (baseado no TBL).

A preliminary evaluation of a novel method to monitor a triple antioxidant combination (vitamins E, C and alpha-lipoic acid) in diabetic volunteers using in vitro methaemoglobin formation

Eight otherwise healthy diabetic volunteers took a daily antioxidant supplement consisting of vitamin E (200 IU), vitamin C (250 mg) and α-lipoic acid (90 mg) for a period of 6 weeks. Diabetic dapsone hydroxylamine-mediated methaemoglobin formation and resistance to erythrocytic thiol depletion was compared with age and sex-matched non-diabetic subjects. At time zero, methaemoglobin formation in the non-diabetic subjects was greater at all four time points compared with that of the diabetic subjects. Resistance to glutathione depletion was initially greater in non-diabetic compared with diabetic samples. Half-way through the study (3 weeks), there were no differences between the two groups in methaemoglobin formation and thiol depletion in the diabetic samples was now lower than the non-diabetic samples at 10 and 20 min. At 6 weeks, diabetic erythrocytic thiol levels remained greater than those of non-diabetics. HbA1c values were significantly reduced in the diabetic subjects at 6 weeks compared with time zero values. At 10 weeks, 4 weeks after the end of supplementation, the diabetic HbA1c values significantly increased to the point where they were not significantly different from the time zero values. Total antioxidant status measurement (TAS) indicated that diabetic plasma antioxidant capacity was significantly improved during antioxidant supplementation. Conversion of α-lipoic acid to dihydrolipoic acid (DHLA) in vivo led to potent interference in a standard fructosamine assay kit, negating its use in this study. This report suggests that triple antioxidant therapy in diabetic volunteers attenuates the in vitro experimental oxidative stress of methaemoglobin formation and reduces haemoglobin glycation in vivo. © 2003 Elsevier Science B.V. All rights reserved.

Eradication of Helicobacter pylori in Children by Triple Therapy Regimens of Amoxicillin, Omeprazole, and Clarithromycin or Azithromycin

Background and Objectives: The present study aimed to evaluate the effect of classical and azithromycin-containing triple therapy eradication regimen against H. pylori in children, and to determine the level of patients’ tolerance. Patients and Methods: This single clinical trial was performed in 2014 on 2 to 15 years old children. All children, in whom H. Pylori infection was confirmed through multiple biopsies of the stomach and required treatment, were enrolled in the study. H. Pylori-positive patients were treated alternately with two different drug regimens; Group OCA received clarithromycin 7.5 mg/kg/day every 12 hours for 10 days, amoxicillin 50 mg/kg/day every 12 hours for 10 days, and omeprazole 1 mg/kg/day every 12 hours for two weeks, and Group OAA received azithromycin 10 mg/kg/day once a day (before meal) for 6 days along with amoxicillin and omeprazole. Four to six weeks after completion of treatment, patients’ stool was tested for H. Pylori through the monoclonal method using the Helicobacter antigen quick kit. Results: There were no significant differences between the two groups regarding gender and age of patients. Based on ITT analysis, the therapeutic response in the OAA and OCA groups were 56.2% and 62.5%, respectively (P = 0.40). Drug adverse effects were 15.6% in the OCA and 3.1% in the OAA group (P = 0.19). Conclusions: The therapeutic response was seen in more than half of the patients treated with triple therapy of H. Pylori eradication regimen including azithromycin or clarithromycin, and there was no significant difference between the two treatment groups. Keywords: Treatment,

Presencia de Hezbollah en la triple frontera, un desafío para las políticas de seguridad conjuntas de Argentina, Brasil y Paraguay (2001-2006)

El grupo fundamentalista Hezbollah, nació en el Líbano y propagó su ideología por el mundo a finales del siglo XX y principios del siglo XXI. En el punto más álgido de su expansión, instaló una de sus células en el límite entre Argentina, Brasil y Paraguay, generando un riesgo para la región. Por esto, se hizo necesario crear políticas conjuntas de seguridad en la Triple Frontera con el fin de combatir la amenaza en la zona entre los años 2001 y 2006. Aunque teóricamente es necesario instaurar un Complejo Regional de Seguridad para mitigar los efectos de la amenaza, esto representó una complicación para los actores estatales, principalmente por sus divergencias geopolíticas, sociales, así como, las distintas percepciones sobre el grupo terrorista presente. Esto, resultó por dificultar la respuesta acertada en temas seguridad en la frontera.

Electrochemistry of Heteroleptic Tris(phthalocyaninato) Rare Earth(III) Complexes

The electrochemical characteristics of a series of heteroleptic tris(phthalocyaninato) complexes with identical rare earths or mixed rare earths (Pc)M(OOPc)M(OOPc) [M = Eu...Lu, Y; H2Pc = unsubstituted phthalocyanine, H2(OOPc) = 3,4,12,13,21,22,30,31-octakis(octyloxy)phthalocyanine] and (Pc)Eu(OOPc)Er(OOPc) have been recorded and studied comparatively by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in CH2Cl2 containing 0.1 M tetrabutylammonium perchlorate (TBAP). Up to five quasi-reversible one-electron oxidations and four one-electron reductions have been revealed. The half-wave potentials of the first, second and fifth oxidations depend on the size of the metal center, but the fifth changes in the opposite direction to that of the first two. Moreover, the difference in redox potentials of the first oxidation and first reduction for (Pc)M(OOPc)M(OOPc), 0.85−0.98 V, also decreases linearly along with decreasing rare earth ion radius, clearly showing the rare earth ion size effect and indicating enhanced π−π interactions in the triple-deckers connected by smaller lanthanides. This order follows the red-shift seen in the lowest energy band of triple-decker compounds. The electronic differences between the lanthanides and yttrium are more apparent for triple-decker sandwich complexes than for the analogous double-deckers. By comparing triple-decker, double-decker and mononuclear [ZnII] complexes containing the OOPc ligand, the HOMO−LUMO gap has been shown to contract approximately linearly with the number of stacked phthalocyanine ligands.