955 resultados para Test accelerati a fatica, diagramma di Wohler, kurtosis, Papoulis


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Dithiols of N-hexadecyl-3,6-di(p-mercaptophenylacetylene)carbazole (HDMC) have been synthesized and employed to form self-assembled monolayers (SAMs) on gold. One characteristic of the HDMC molecule is its peculiar molecular structure consisting of a large and rigid headgroup and a small and flexible alkyl-chain tail. HDMC adsorbates can attach to gold substrates by a strong Au-S bond with weak van der Waals interactions between the alkyl-chain tails, leading to a loosely packed hydrophobic SAM. In this way we can couple hybrid bilayer membranes (HBMs) to gold surfaces with more likeness to a cell bilayer than the conventional HBMs based on densely packed long-chain alkanethiol SAMs. The insulating properties and stability of the HDMC monolayer as well as the HDMC/lipid bilayer on gold have been investigated by electrochemical techniques including cyclic voltammetry and impedance spectroscopy. To test whether the quality of the bilayer is sufficiently high for biomimetic research, we incorporated the pore-forming protein a-hemolysin) and the horseradish peroxidase into the bilayers, respectively.

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This thesis investigates the pricing effects of idiosyncratic moments. We document that idiosyncratic moments, namely idiosyncratic skewness and idiosyncratic kurtosis vary over time. If a factor/characteristic is priced, it must show minimum variation to be correlated with stock returns. Moreover, we can identify two structural breaks in the time series of idiosyncratic kurtosis. Using a sample of US stocks traded on NYSE, AMEX and NASDAQ markets from January 1970 to December 2013, we run Fama-MacBeth test at the individual stock level. We document a negative and significant pricing effect of idiosyncratic skewness, consistent with the finding of Boyer et al. (2010). We also report that neither idiosyncratic volatility nor idiosyncratic kurtosis are consistently priced. We run robustness tests using different model specifications and period sub-samples. Our results are robust to the different factors and characteristics usually included in the Fama-MacBeth pricing tests. We also split first our sample using endogenously determined structural breaks. Second, we divide our sample into three equal sub-periods. The results are consistent with our main findings suggesting that expected returns of individual stocks are explained by idiosyncratic skewness. Both idiosyncratic volatility and idiosyncratic kurtosis are irrelevant to asset prices at the individual stock level. As an alternative method, we run Fama-MacBeth tests at the portfolio level. We find that idiosyncratic skewness is not significantly related to returns on idiosyncratic skewness-sorted portfolios. However, it is significant when tested against idiosyncratic kurtosis sorted portfolios.

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This thesis investigates the pricing effects of idiosyncratic moments. We document that idiosyncratic moments, namely idiosyncratic skewness and idiosyncratic kurtosis vary over time. If a factor/characteristic is priced, it must show minimum variation to be correlated with stock returns. Moreover, we can identify two structural breaks in the time series of idiosyncratic kurtosis. Using a sample of US stocks traded on NYSE, AMEX and NASDAQ markets from January 1970 to December 2013, we run Fama-MacBeth test at the individual stock level. We document a negative and significant pricing effect of idiosyncratic skewness, consistent with the finding of Boyer et al. (2010). We also report that neither idiosyncratic volatility nor idiosyncratic kurtosis are consistently priced. We run robustness tests using different model specifications and period sub-samples. Our results are robust to the different factors and characteristics usually included in the Fama-MacBeth pricing tests. We also split first our sample using endogenously determined structural breaks. Second, we divide our sample into three equal sub-periods. The results are consistent with our main findings suggesting that expected returns of individual stocks are explained by idiosyncratic skewness. Both idiosyncratic volatility and idiosyncratic kurtosis are irrelevant to asset prices at the individual stock level. As an alternative method, we run Fama-MacBeth tests at the portfolio level. We find that idiosyncratic skewness is not significantly related to returns on idiosyncratic skewness-sorted portfolios. However, it is significant when tested against idiosyncratic kurtosis sorted portfolios.

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We study the problem of testing the error distribution in a multivariate linear regression (MLR) model. The tests are functions of appropriately standardized multivariate least squares residuals whose distribution is invariant to the unknown cross-equation error covariance matrix. Empirical multivariate skewness and kurtosis criteria are then compared to simulation-based estimate of their expected value under the hypothesized distribution. Special cases considered include testing multivariate normal, Student t; normal mixtures and stable error models. In the Gaussian case, finite-sample versions of the standard multivariate skewness and kurtosis tests are derived. To do this, we exploit simple, double and multi-stage Monte Carlo test methods. For non-Gaussian distribution families involving nuisance parameters, confidence sets are derived for the the nuisance parameters and the error distribution. The procedures considered are evaluated in a small simulation experi-ment. Finally, the tests are applied to an asset pricing model with observable risk-free rates, using monthly returns on New York Stock Exchange (NYSE) portfolios over five-year subperiods from 1926-1995.

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Planners in public and private institutions would like coherent forecasts of the components of age-specic mortality, such as causes of death. This has been di cult to achieve because the relative values of the forecast components often fail to behave in a way that is coherent with historical experience. In addition, when the group forecasts are combined the result is often incompatible with an all-groups forecast. It has been shown that cause-specic mortality forecasts are pessimistic when compared with all-cause forecasts (Wilmoth, 1995). This paper abandons the conventional approach of using log mortality rates and forecasts the density of deaths in the life table. Since these values obey a unit sum constraint for both conventional single-decrement life tables (only one absorbing state) and multiple-decrement tables (more than one absorbing state), they are intrinsically relative rather than absolute values across decrements as well as ages. Using the methods of Compositional Data Analysis pioneered by Aitchison (1986), death densities are transformed into the real space so that the full range of multivariate statistics can be applied, then back-transformed to positive values so that the unit sum constraint is honoured. The structure of the best-known, single-decrement mortality-rate forecasting model, devised by Lee and Carter (1992), is expressed in compositional form and the results from the two models are compared. The compositional model is extended to a multiple-decrement form and used to forecast mortality by cause of death for Japan

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1) Realizar un trabajo experimental con sujetos normales y deficientes de Sevilla, Córdoba y Las Palmas de Gran Canaria 2) Averiguar la correlación existente entre el test de la figura humana de F.L. Goodenough y D.B Harris y las calificaciones escolares de media general de la muestra escogida 3) Ofrecer a dichas zonas una estandarización del test de la figura humana de Goodenough y Harris, y de este modo hacer extensible a la población española un nuevo elemento más en la diagnosis de la inteligencia. 610 sujetos de escuelas normales en edades comprendidas entre los 6 y 10 años y 162 deficientes mentales de 5 a 21 años escolarizados en centros específicos, todos ellos de Sevilla y Córdoba, 500 niños de escuelas normales de Las Palmas de Gran Canaria de edades comprendidas entre 6 y 10 años y 50 sujetos de centros específicos de 9 años de edad. Analiza las bases teóricas del test de Goodenough y Harris, relaciona los estudios españoles en torno al test de Goodenough y plantea algunas hipótesis para comprobarlas con una investigación que se realiza en dos muestras con niños normales y niños deficientes mentales en las provincias españolas de Sevilla, Córdoba y Las Palmas de Gran Canaria. Test del dibujo de la figura humana de Goodenough-Harris. El test de Goodneough y Harris ha sido aplicado según las normas indicadas en el manual del Test della figura umana (ed. Organizzazioni Speciali, Firenze) en cuanto a motivar a los niños en la realización del dibujo del hombre y de la mujer y siguiendo las pautas descriptivas. Terminado el dibujo del hombre se les presentaba otra hoja para que dibujasen una mujer y concluido éste, se les presentaba un cuestionario para que lo respondiesen teniendo delante la figura del hombre y de la mujer. La aplicación del test se realizó en las primeras horas de clase, bien de la mañana o de la tarde, para evitar momentos en que los alumnos se encontrasen cansados y dicho cansancio pudiese influir en los resultados del test. Se procuró durante la aplicación del test un ambiente de relax y simpatía entre testista y alumnos y se invalidaron todos aquellos protocolos que no cumplían las normas exigidas por el test, los cuales fueron 10 en total. 1) La obtención de una correlación positiva y significativa entre el dibujo del hombre y de la mujer en ambas muestras de sujetos normales, demuestran la fidelidad del test. 2) La correlación del test tanto en el dibujo del hombre como en el de la mujer, con las notas escolares de media del curso anterior, en las áreas de ciencias naturales y dibujo, son todas ellas positivas y en su mayoría significativas, lo que significa una efectiva correlación entre el test y el rendimiento escolar. 3) el resultado de las diversas correlaciones positivas y significativas entre las notas de media del curso anterior y de estas con el test, pueden ofrecer información del tipo de inteligencia que mide el test, pudiendo predecir el éxito escolar en las áreas tratadas más que en otras materias. Sin olvidar que la predicción debe ser estudiada y profundizada. 4) No existen diferencias significativas en los resultados del test entre una edad y la inmediatamente superior, pero en general, existe diferencia significativa cuando se trata de dos años de diferencia. 5) Las diferencias entre la muestra Sevilla y Córdoba con Las Palmas de Gran Canaria son significativas, a favor de los niños andaluces. 6) En la muestra de sujetos deficientes mentales existe entre el dibujo del hombre y de la mujer una correlación positiva y significativa en todos los casos, salvo en las niñas de la muestra de Las Palmas, que aunque positiva no es significativa. Por lo cual sólo se puede hablar de una moderada correlación entre los dos dibujos. 7) Nada certero se puede afirmar respecto a las diferencias significativas de medias tanto al comparar los resultados obtenidos por los deficientes mentales niños y niñas de la muestra Sevilla y Córdoba, como al compararlos con la muestra de Las Palmas. El pequeño número de sujetos, el grado diferente de deficiencia dentro de las diversas edades no controladas harían equívocas e infundadas cualquier afirmación. 1) Entre las técnicas y los tests que se emplean con niños, el test de la figura humana es significativo, interesante y agradable, ya que a la mayoría de los sujetos les encanta dibujar y pintar. Además, tanto los sujetos normales como los deficientes dibujan, en numerosas ocasiones, figuras humanas. La representación del dibujo de la persona humana en sus diversas etapas es un reflejo del desarrollo intelectual del niño, puesto que el niño no pinta lo que ve sino lo que sabe. Por consiguiente, los resultado con el uso del test utilizado han sido satisfactorios tanto en normales como en deficientes.

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Trabajo que recoge los resultados tras la aplicación del test de Raven en diferentes grupos de EGB para conocer de manera objetiva la realidad de los alumnos españoles de este nivel educativo. Todo ello va precedido por unas normas simplificadas de aplicación, acompañadas de las que dió el autor del test, y un estudio sintético y práctico de las variadas y diversas potencialidades del mismo encaminadas al conocimiento exhaustivo del examinando, así como diversas observaciones prácticas del autor..

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In this paper we test whether the disclosure of test scores has direct impacts on student performance, school composition and school inputs. We take advantage of the discontinuity on the disclosure rules of The National Secondary Education Examination (ENEM) run in Brazil by the Ministry of Education: In 2006 it was established that the 2005 mean score results would be disclosed for schools with ten or more students who took the exam in the previous year. We use a regression discontinuity design to estimate the e ects of test disclosure. Our results indicate that private schools that had their average scores released in 2005 outperformed those that did not by 0.2-0.6 in 2007. We did not nd same results for public schools. Moreover, we did not nd evidence that treated schools adjusted their inputs or that there was major changes in the students composition of treated schools. These ndings allow us to interpret that the main mechanism driving the di erences in performance was the increased levels of students', teachers' and principals' e ort exerted by those in schools that had scores publicized.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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This paper discusses the design and performance of the time measurement technique and of the synchronization systems of the CMS hadron calorimeter. Time measurement performance results are presented from test beam data taken in the years 2004 and 2006. For hadronic showers of energy greater than 100 GeV, the timing resolution is measured to be about 1.2 ns. Time synchronization and out-of-time background rejection results are presented from the Cosmic Run At Four Tesla and LHC beam runs taken in the Autumn of 2008. The inter-channel synchronization is measured to be within 2 ns. © 2010 IOP Publishing Ltd and SISSA.

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Pós-graduação em Odontologia Restauradora - ICT

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