Time-resolved gas-phase kinetic, quantum chemical, and RRKM studies of reactions of silylene with alcohols

Time-resolved kinetic studies of silylene, SiH2, generated by laser flash photolysis of 1-silacyclopent-3-ene and phenylsilane, have been carried out to obtain rate constants for its bimolecular reactions with methanol, ethanol, 1-propanol, 1-butanol and 2-methyl-1-butanol. The reactions were studied in the gas phase over the pressure range 1-100 Torr in SF6 bath gas, at room temperature. In the study with methanol several buffer gases were used. All five reactions showed pressure dependences characteristic of third body assisted association reactions. The rate constant pressure dependences were modelled using RRKM theory, based on Eo values of the association complexes obtained by ab initio calculation (G3 level). Transition state models were adjusted to fit experimental fall-off curves and extrapolated to obtain k∞ values in the range 1.9 to 4.5 × 10-10 cm3 molecule-1 s-1. These numbers, corresponding to the true bimolecular rate constants, indicate efficiencies of between 16 and 67% of the collision rates for these reactions. In the reaction of SiH2 + MeOH there is a small kinetic component to the rate which is second order in MeOH (at low total pressures). This suggests an additional catalysed reaction pathway, which is supported by the ab initio calculations. These calculations have been used to define specific MeOH-for-H2O substitution effects on this catalytic pathway. Where possible our experimental and theoretical results are compared with those of previous studies.

Business cycle asymmetries: characterisation and testing based on Markov-switching autoregressions

Tests for business cycle asymmetries are developed for Markov-switching autoregressive models. The tests of deepness, steepness, and sharpness are Wald statistics, which have standard asymptotics. For the standard two-regime model of expansions and contractions, deepness is shown to imply sharpness (and vice versa), whereas the process is always nonsteep. Two and three-state models of U.S. GNP growth are used to illustrate the approach, along with models of U.S. investment and consumption growth. The robustness of the tests to model misspecification, and the effects of regime-dependent heteroscedasticity, are investigated.

Teoria científica das empresas e participações societárias estatais - TEPSES: governanças pública, corporativa e o caso do Brasil

RESUMO Ao identificar a existência de lacuna teórica, o presente trabalho definiu como seu objetivo: Estabelecer os alicerces de uma epistéme sobre o fenômeno por meio do desenvolvimento de um arcabouço capaz de a) direcionar e dar sustentação à construção e ao desenvolvimento coletivo de uma Teoria Científica das Empresas e Participações Societárias Estatais – TEPSES, e de b) identificar elementos que viabilizem o desenvolvimento de respostas à questão aplicada central: Como devem os governos definir as missões, os critérios de desempenho e os mecanismos de governança das empresas estatais em um ambiente em mudança? Considerando sua materialidade, a relevância estratégica dessas empresas para os Estados contemporâneos, suas implicações para os processos de globalização e a administração uma ciência aplicada a demandarem nível de análise societal e abordagem multiparadigmática, o arcabouço e seus elementos proporcionaram resposta a várias inquietações e problemas expressos, alguns por mais de meio século, por autoridades no campo como Pritchett, Seidman, Sherwood, Shepherd, Aharoni, Millward, Hinds e Baumol. Oferecendo por redução fenomenológica uma definição de conceito universal para as empresas estatais e introduzindo, inter allia, os conceitos de capacidade essencial de Estado em seu intervalo – CEEi e de estatal patrimonial, que permitiram a construção de uma escala de interesses públicos; o arcabouço teórico focado rueschemeyeriano da TEPSES, constrói pontes entre os hemisférios da grande dicotomia do direito e entre aspectos de governanças pública e corporativa, por meio de tipologias lazarsfeldianas. Em suas seis dimensões iniciais e trinta e três relações o arcabouço foi aplicado por sondagem plausibilística ao caso das estatais diretas brasileiras, apresentando elevado grau de plausibilidade e qualidade, inclusive segundo critérios de Wacker. As formulações e explicitações da TEPSES oferecem respostas e possibilidades de tratamento a várias questões científicas mais amplas como: o paradoxo do conhecimento na regulação de Balleisen, a armadilha de Schneider, a dúvida de Ikeda/Mises e a reabertura da questão de adequação organizacional pelo nobel Simon; proporcionando ainda extensões a: tipologia de estruturas de governança do nobel Williamson, as concepções de sociedade prismática de Riggs, a definição da administração como ciência aplicada do nobel Simon, as formulações institucionalistas de Acemoglu e Robinson e as abordagens sobre intervenção de Estado do nobel Stiglitz. O arcabouço da TEPSES possibilita: a) a cada país, construir sua própria tipologia empírica de empresas estatais e assim geri-las a partir de respostas customizadas à questão aplicada central, analisar sua adequação como instrumento de políticas públicas e desenvolver critérios para suas privatizações; b) a gestores, pesquisadores e estudiosos de caso situar e analisar suas empresas a partir do arcabouço; c) às pesquisas pretéritas, terem seus dados reinterpretados à luz de um novo referencial e d) a todos, a possibilidade de conectarem seus trabalhos à epistéme da qual a TEPSES é alicerce e repositório. Conclui-se que o grau de relevância, em nível global, do fenômeno é na realidade muito superior à sua materialidade e ao grau de relevância atribuído inicialmente, devido à identificação de sua condição como fator empírico de capacidades de Estado, uma vez que à ausência e deficiências dessas capacidades são atribuídos colapsos e débâcles de vários Estados nacionais, que resultaram em elevadíssimos e incalculáveis custos humanos.

Sobrevivência e tamanho populacional do Tiê-preto Tachyphonus Rufus (aves: thraupidae) em fragmento de restinga no extremo Norte da Mata Atlântica

For a long time, we believed in the pattern that tropical and south hemisphere species have high survival. Nowadays results began to contradict this pattern, indicating the need for further studies. Despite the advanced state of the study of bird population parameters, little is known about their variation throughout the year and the factors affecting them. Reproduction, for example, is one factor that may alter adult survival rates, because during this process the breeding pair allocates resources to maintain itself to maintain offspring, making itself more susceptible to diseases and predation. The aim of this study was to estimate survival and population size of a Central and South America passerine, Tachyphonus rufus (Boddaert, 1783), testing hypotheses about the factors that define these parameters. We performed data collection between Nov/2010 and ago/2012 in 12 ha plot, in a fragment of Atlantic Forest in northeastern Brazil. We used capture-mark-recapture methods to generate estimates using Closed Design Robust model in the program MARK. We generated Multi-state models to test some assumptions inherent to Closed Robust Design. The influence of co-variables (time, rain and reproductive cycle) and the effect of transient individuals were measured. Capture, recapture and apparent survival parameters were defined by reproductive cycle, while temporary dispersal was influence by rain. The estimates showed a higher apparent survival during the non-breeding period (92% ± 1%) than during breeding (40% ± 9%), revealing a cost of reproduction and suggesting a trade-off between surviving and reproducing. The low annual survival observed (34%) did not corroborate the pattern of high rates expected for a tropical bird. The largest population size was estimated to be 56 individuals in Nov/11, explained by high recruitment of juveniles, while the lowest observed in May/12: 10 individuals, probably as a result of massive influx of competitor species. Results from this study add to the growing literature on life history of Neotropical species. We encourage studies like this especially in Brazil, where there are few information, and suggest that covariates related to habitat quality and environmental changes should be tested, so that we can generate increasingly reliable models

Caracterização biométrica de frutos de coqueiro, Vocos nucifera L. variedade anã-verde, em diferentes estádios de desenvolvimento

Objetivou-se determinar a curva de crescimento da massa do fruto e diâmetros externos longitudinal e transversal, bem como os acúmulos do albúmen sólido (polpa) e albúmen líquido (água-de-coco) e sua caracterização sensorial em diferentes estádios. Frutos de coqueiro-anão-verde (Cocos nucifera L.) foram avaliados em 26 épocas, durante o período de sua formação, em intervalos quinzenais, de abril de 2004 a maio de 2005, no município de Bebedouro - SP. Foram aplicados aos dados modelos de regressão logística e logística combinada com exponencial quadrática, obtendo-se elevados graus de ajustes. O diâmetro externo longitudinal alcançou a média máxima de 20,12 cm aos 375 dias após a abertura da inflorescência (d.a.a.i.), enquanto o diâmetro externo transversal alcançou 14,57 cm, aos 345 (d.a.a.i.). Os frutos apresentaram maior massa no período entre 255 e 315 (d.a.a.i.), não havendo diferença estatística significativa neste período. O albúmen sólido teve início de formação aos 225 (d.a.a.i.), chegando aos 375 dias com a massa média de 214,78 gramas. O maior volume médio de albúmen líquido foi verificado em frutos com 8,5 meses de idade com adequado sabor. Esses dados são importantes indicativos do ponto ideal de colheita dos frutos de coqueiro-anão-verde, na região de Bebedouro - SP, para o consumo in natura da água-de-coco.

Ecological modeling and pest population management: a possible and necessary connection in a changing world

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

On the stability of the extracellular hemoglobin of Glossoscolex paulistus, in two iron oxidation states, in the presence of urea

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

Simulação da produção e combustão de gás de síntese oriundo de gaseificadores de leite fixo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

On the stability of the extracellular hemoglobin of Glossoscolex paulistus, in two iron oxidation states, in the presence of urea

The stability of the Glossoscolex paulistus hemoglobin (HbGp), in two iron oxidation states (and three forms), as monitored by optical absorption, fluorescence emission and circular dichroism (CD) spectroscopies, in the presence of the chaotropic agent urea, is studied. HbGp oligomeric dissociation, denaturation and iron oxidation are observed. CD data show that the cyanomet-HbGp is more stable than the oxy-form. Oxy- and cyanomet-HbGp show good fits on the basis of a two state model with critical urea concentrations at 220-222 nm of 5.1 +/- 0.2 and 6.1 +/- 0.1 mol/L, respectively. The three-state model was able to reveal a subtle second transition at lower urea concentration (1.0-2.0 mol/L) associated to partial oligomeric dissociation. The intermediate state for oxy- and cyanomet-HbGp is very similar to the native state. For met-HbGp, a different equilibrium, in the presence of urea, is observed. A sharp transition at 1.95 +/- 0.05 mol/L of denaturant is observed, associated to oligomeric dissociation and hemichrome formation. In this case, analysis by a three-state model reveals the great similarity between the intermediate and the unfolded states. Analysis of spectroscopic data, by two-state and three-state models, reveals consistency of obtained thermodynamic parameters for HbGp urea denaturation. (C) 2012 Elsevier Inc. All rights reserved.

Thermodynamic and mechanical properties of polymer-solvent systems

This work presents the results of theoretical and experimental characterization of thermodynamic, mechanical and transport properties in polymer solvent systems. The polymer solvent pairs considered ranged to those in which the polymer is rubbery, to those in which the initially glassy polymeric matrix is plasticized by the action of the low molecular weight species. Advanced Equation of State models have been adopted for thermodynamic modeling,along with a rigorous procedure that enables to extend their applicability to the non equilibrium, glassy region. Mass sorption kinetics had been modeled with phenomenological models and with advanced kinetic models.

Domestic hot water consumption vs. solar thermal energy storage: the optimum size of the storage tank

Many efforts have been made in order to adequate the production of a solar thermal collector field to the consumption of domestic hot water of the inhabitants of a building. In that sense, much has been achieved in different domains: research agencies, government policies and manufacturers. However, most of the design rules of the solar plants are based on steady state models, whereas solar irradiance, consumption and thermal accumulation are inherently transient processes. As a result of this lack of physical accuracy, thermal storage tanks are sometimes left to be as large as the designer decides without any aforementioned precise recommendation. This can be a problem if solar thermal systems are meant to be implemented in nowadays buildings, where there is a shortage of space. In addition to that, an excessive storage volume could not result more efficient in many residential applications, but costly, extreme in space consumption and in some cases too heavy. A proprietary transient simulation program has been developed and validated with a detailed measurement campaign in an experimental facility. In situ environmental data have been obtained through a whole year of operation. They have been gathered at intervals of 10 min for a solar plant of 50 m2 with a storage tank of 3 m3, including the equipment for domestic hot water production of a typical apartment building. This program has been used to obtain the design and dimensioning criteria of DHW solar plants under daily transient conditions throughout a year and more specifically the size of the storage tank for a multi storey apartment building. Comparison of the simulation results with the current Spanish regulation applicable, “Código Técnico de la Edificación” (CTE 2006), offers fruitful details and establishes solar facilities dimensioning criteria.

Social Democracy, Globalization and Governance: Why is there no European Left Program in the EU? CES Germany & Europe Working Papers, No. 00.6, April 2000

This paper addresses globalization and governance in the EU by attempting to generate some plausible hypotheses that might explain the policy choices of the 12 out of 15 European democratic left governments. With all of the discussion in recent years of a democratic deficit, and then need to maintain a "social Europe," why have these governments not produced more explicit left-wing policies? It suggests three possible hypotheses to account for this apparently mysterious outcome. Hypothesis #1: They want to but they can't. Hypothesis #2: They don't want to because they aren't really left anymore. Hypothesis #3: They could, but they all are suffering from a fundamental failure of imagination. The paper explores each of these hypotheses in two ways. First it examines the initial years of the Schröder government in Germany apparently, pursuing each of these three hypotheses and different times during this period. Then it looks more systematically and comparatively and each of the three hypotheses by including analysis both of Germany and several other EU member states. The larger goal of this work is to provoke discussion and research on what role left political movements can actually play. Is it even reasonable to expect such a group of nation states to develop innovative forms of cross-national governance? Or are new and/or revised forms of representation and governance beyond traditional nation-state models.

British and European influences on the "Australian Way" from the 1980s

Commonwealth countries share their British social policy legacy in a variety of ways. Autstralia attempted to adopt the postwar new Fabian welfare state model at the very time when international economic circumstances undermined its Keynesian foundation. With Labor governments in power from 1983 to 1996, Australia diverged significantly from the neo-liberal reform path adopted in the United Kingdom. Australian governments looked increasingly to European social democracies for alternative social policy model In a manner anticipating the Third Way. the tendency was towards mixing neo-liberal economics with social democratic welfare. The Australian Third Way which resulted proved unstable. Current social reformers, the paper proposes, ought to revisit a neglected but characteristically British emphasis on the need for a measure of socialization of investment to underpin redistributive strategies.

Entanglement and boundary critical phenomena

We investigate boundary critical phenomena from a quantum-information perspective. Bipartite entanglement in the ground state of one-dimensional quantum systems is quantified using the Renyi entropy S-alpha, which includes the von Neumann entropy (alpha -> 1) and the single-copy entanglement (alpha ->infinity) as special cases. We identify the contribution of the boundaries to the Renyi entropy, and show that there is an entanglement loss along boundary renormalization group (RG) flows. This property, which is intimately related to the Affleck-Ludwig g theorem, is a consequence of majorization relations between the spectra of the reduced density matrix along the boundary RG flows. We also point out that the bulk contribution to the single-copy entanglement is half of that to the von Neumann entropy, whereas the boundary contribution is the same.

Studies of turbulent flows in continuous casting of steel with and without magnetic field

This thesis develops and tests various transient and steady-state computational models such as direct numerical simulation (DNS), large eddy simulation (LES), filtered unsteady Reynolds-averaged Navier-Stokes (URANS) and steady Reynolds-averaged Navier-Stokes (RANS) with and without magnetic field to investigate turbulent flows in canonical as well as in the nozzle and mold geometries of the continuous casting process. The direct numerical simulations are first performed in channel, square and 2:1 aspect rectangular ducts to investigate the effect of magnetic field on turbulent flows. The rectangular duct is a more practical geometry for continuous casting nozzle and mold and has the option of applying magnetic field either perpendicular to broader side or shorter side. This work forms the part of a graphic processing unit (GPU) based CFD code (CU-FLOW) development for magnetohydrodynamic (MHD) turbulent flows. The DNS results revealed interesting effects of the magnetic field and its orientation on primary, secondary flows (instantaneous and mean), Reynolds stresses, turbulent kinetic energy (TKE) budgets, momentum budgets and frictional losses, besides providing DNS database for two-wall bounded square and rectangular duct MHD turbulent flows. Further, the low- and high-Reynolds number RANS models (k-ε and Reynolds stress models) are developed and tested with DNS databases for channel and square duct flows with and without magnetic field. The MHD sink terms in k- and ε-equations are implemented as proposed by Kenjereš and Hanjalić using a user defined function (UDF) in FLUENT. This work revealed varying accuracies of different RANS models at different levels. This work is useful for industry to understand the accuracies of these models, including continuous casting. After realizing the accuracy and computational cost of RANS models, the steady-state k-ε model is then combined with the particle image velocimetry (PIV) and impeller probe velocity measurements in a 1/3rd scale water model to study the flow quality coming out of the well- and mountain-bottom nozzles and the effect of stopper-rod misalignment on fluid flow. The mountain-bottom nozzle was found more prone to the longtime asymmetries and higher surface velocities. The left misalignment of stopper gave higher surface velocity on the right leading to significantly large number of vortices forming behind the nozzle on the left. Later, the transient and steady-state models such as LES, filtered URANS and steady RANS models are combined with ultrasonic Doppler velocimetry (UDV) measurements in a GaInSn model of typical continuous casting process. LES-CU-LOW is the fastest and the most accurate model owing to much finer mesh and a smaller timestep. This work provided a good understanding on the performance of these models. The behavior of instantaneous flows, Reynolds stresses and proper orthogonal decomposition (POD) analysis quantified the nozzle bottom swirl and its importance on the turbulent flow in the mold. Afterwards, the aforementioned work in GaInSn model is extended with electromagnetic braking (EMBr) to help optimize a ruler-type brake and its location for the continuous casting process. The magnetic field suppressed turbulence and promoted vortical structures with their axis aligned with the magnetic field suggesting tendency towards 2-d turbulence. The stronger magnetic field at the nozzle well and around the jet region created large scale and lower frequency flow behavior by suppressing nozzle bottom swirl and its front-back alternation. Based on this work, it is advised to avoid stronger magnetic field around jet and nozzle bottom to get more stable and less defect prone flow.