A robust Bayesian approach to null intercept measurement error model with application to dental data

Measurement error models often arise in epidemiological and clinical research. Usually, in this set up it is assumed that the latent variable has a normal distribution. However, the normality assumption may not be always correct. Skew-normal/independent distribution is a class of asymmetric thick-tailed distributions which includes the Skew-normal distribution as a special case. In this paper, we explore the use of skew-normal/independent distribution as a robust alternative to null intercept measurement error model under a Bayesian paradigm. We assume that the random errors and the unobserved value of the covariate (latent variable) follows jointly a skew-normal/independent distribution, providing an appealing robust alternative to the routine use of symmetric normal distribution in this type of model. Specific distributions examined include univariate and multivariate versions of the skew-normal distribution, the skew-t distributions, the skew-slash distributions and the skew contaminated normal distributions. The methods developed is illustrated using a real data set from a dental clinical trial. (C) 2008 Elsevier B.V. All rights reserved.

Simultaneous determination of chromium and manganese in alumina by slurry sampling graphite furnace atomic absorption spectrometry using NbC and NaF as modifiers

This paper reports a method for the direct and simultaneous determination of Cr and Mn in alumina by slurry sampling graphite furnace atomic absorption spectrometry (SiS-SIMAAS) using niobium carbide (NbC) as a graphite platform modifier and sodium fluoride (NaF) as a matrix modifier. 350 mu g of Nb were thermally deposited on the platform surface allowing the formation of NbC (mp 3500 degrees C) to minimize the reaction between aluminium and carbon of the pyrolytic platform, improving the graphite tube lifetime up to 150 heating cycles. A solution of 0.2 mol L(-1) NaF was used as matrix modifier for alumina dissolution as cryolite-based melt, allowing volatilization during pyrolysis step. Masses (c.a. 50 mg) of sample were suspended in 30 ml of 2.0% (v/v) of HNO(3). Slurry was manually homogenized before sampling. Aliquots of 20 mu l of analytical solutions and slurry samples were co-injected into the graphite tube with 20 mu l of the matrix modifier. In the best conditions of the heating program, pyrolysis and atomization temperatures were 1300 degrees C and 2400 degrees C, respectively. A step of 1000 degrees C was optimized allowing the alumina dissolution to form cryolite. The accuracy of the proposed method has been evaluated by the analysis of standard reference materials. The found concentrations presented no statistical differences compared to the certified values at 95% of the confidence level. Limits of detection were 66 ng g(-1) for Cr and 102 ng g(-1) for Mn and the characteristic masses were 10 and 13 pg for Cr and Mn, respectively.

Measurement of the Viscoelastic Properties of the Vocal Folds

Objectives: Studies of the viscoelastic properties of the vocal folds are normally performed with rheometers that use parallel assigned a fixed value. In tissues subject to variation of thickness plates whose interplate space is usually at between samples, fixed gaps could result in different compressions, compromising the comparison among them. We performed,in experimental study to determine whether different compressions call lead to different results in measurements of dynamic viscosity (DV) of vocal fold samples. Methods: We Measured the DV of vocal fold samples of 10 larynges of cadavers under 3 different compression levels, corresponding to 0.2, 0.5, and 10 N on an 8-mm-diameter parallel-plate rheometer. Results: The DV directly varied with compression. We observed statistically significant differences between the results of 0.2 and 10 N (p = 0.0396) and 0.5 and 10 N (p = 0.0442). Conclusions: The study demonstrated that the level of compression influences the DV measure and Suggests that a defined compression level should be used in rheometric studies of biological tissues.

Measurement of the anodic potential in solid state: A tool for determination of the antioxidant potential of phytomedicine

The electroanalytical techniques are very promissing to perform the quality control of crude vegetable. Solid State Differential Pulse Voltammetry in the supporting electrolyte is able to detect the oxidation signals of the active material, which can be used as a parameter to identify the type of crude vegetable and its antioxidant activity. The working electrode consisted in a carbon paste electrode modified with the powder of vegetable raw material (EMF). The electrochemical measurements were performed in a cell containing the working (EMF), reference (Ag/AgCl, KClsat) and auxiliary (Pt) electrodes.

LASER-TESTING RIG : Measurement System for evaluation of Shape of concentrating reflector for solar collector Absolicon X10

This Thesis project is a part of the all-round automation of production of concentrating solar PV/T systems Absolicon X10. ABSOLICON Solar Concentrator AB has been invented and started production of the prospective solar concentrated system Absolicon X10. The aims of this Thesis project are designing, assembling, calibrating and putting in operation the automatic measurement system intended to evaluate the shape of concentrating parabolic reflectors.On the basis of the requirements of the company administration and needs of real production process the operation conditions for the Laser testing rig were formulated. The basic concept to use laser radiation was defined.At the first step, the complex design of the whole system was made and division on the parts was defined. After the preliminary conducted simulations the function and operation conditions of the all parts were formulated.At the next steps, the detailed design of all the parts was conducted. Most components were ordered from respective companies. Some of the mechanical components were made in the workshop of the company. All parts of the Laser-testing rig were assembled and tested. Software part, which controls the Laser-testing rig work, was created on the LabVIEW basis. To tune and test software part the special simulator was designed and assembled.When all parts were assembled in the complete system, the Laser-testing rig was tested, calibrated and tuned.In the workshop of Absolicon AB, the trial measurements were conducted and Laser-testing rig was installed in the production line at the plant in Soleftea.

Universal Experimental Measurement System «Sun-Walker» : Automotive measurement system for the evaluation of the solar irradiation distribution for the tests of the solar concentrated systems.

This Thesis project is a part of the research conducted in Solar industry. ABSOLICON Solar Concentrator AB has invented and started production of the prospective solar concentrated system Absolicon X10. The aims of this Thesis project are designing, assembling, calibrating and putting in operation the automatic measurement system intended to evaluate distribution of density of solar radiation in the focal line of the concentrated parabolic reflectors and to measure radiation from the artificial source of light being a calibration-testing tool.On the basis of the requirements of the company’s administration and needs of designing the concentrated reflectors the operation conditions for the Sun-Walker were formulated. As the first step, the complex design of the whole system was made and division on the parts was specified. After the preliminary conducted simulation of the functions and operation conditions of the all parts were formulated.As the next steps, the detailed design of all the parts was made. Most components were ordered from respective companies. Some of the mechanical components were made in the workshop of the company. All parts of the Sun-Walker were assembled and tested. The software part, which controls the Sun-Walker work and conducts measurements of solar irradiation, was created on the LabVIEW basis. To tune and test the software part, the special simulator was designed and assembled.When all parts were assembled in the complete system, the Sun-Walker was tested, calibrated and tuned.

Effects of a quantum measurement on the electric conductivity : Application to graphene

We generalize the standard linear-response (Kubo) theory to obtain the conductivity of a system that is subject to a quantum measurement of the current. Our approach can be used to specifically elucidate how back-action inherent to quantum measurements affects electronic transport. To illustrate the utility of our general formalism, we calculate the frequency-dependent conductivity of graphene and discuss the effect of measurement-induced decoherence on its value in the dc limit. We are able to resolve an ambiguity related to the parametric dependence of the minimal conductivity.

New Programs and Accreditations: Meaningful Measurement & Assessment

This article provides a blueprint for successful library strategies in support of accreditations for regional bodies as well as reviews of discipline-specific academic programs spanning a wide range of knowledge areas.

Public expenditures taxation and welfare measurement

this article addresses the welfare and macroeconomics effects of fiscal policy in a frarnework where govemment chooses tax rates and the distribution of revenues between consumption and investment. We construct and simulate a model where public consumption affects individuaIs' utility and public capital is an argument of the production function. The simulations suggest that by simply reallocating expenditures from consumption to investment, the govemment can increase the equilibrium leveIs of capital stock, hours worked, output and labor productivity. Funhennore, we 'show that the magnitude and direction of the long run impact of fiscal policy depends on the size of the elasticity of output to public capital. If this parameter is high enough, it may be the case that capital stock, within limits, increases with tax rates.

Marketing performance measurement : overview of approaches and practices for high technology firms

Um levantamento de 320 executivos de marketing feito pelo Conselho CMO e divulgado em junho de 2004 indicou que poucas companhias de alta tecnologia (menos de 20% das empresas entrevistadas) têm desenvolvido medidas e métricas úteis e expressivas para as suas organizações de marketing. Porém a pesquisa também revelou que companhias que estabeleceram medidas formais e compreensivas atingiram resultados financeiros superiores e tiveram mais confiança do CEO na função de marketing. Esta dissertação provê uma visão geral da informação precisa para executivos de marketing entenderem e implementarem processos para medição de performance de marketing (MPM) em suas organizações. Ela levanta questões para gerentes de marketing na industria de alta tecnologia com respeito às demandas para maior responsabilidade final, valor de medição para o melhoramento dos processos de marketing, iniciativas para determinar a lucratividade dos investimentos em marketing, e a importância das atividades de marketing nos relatórios corporativos. Esta dissertação defende a implementação de MPM, mapeando seus benefícios de medição para ambos gerentes de marketing e as suas empresas. o trabalho logo explora alguns conceitos gerais de medição de marketing e investiga algumas abordagens a MPM propostas pela industria, pela comunidade acadêmica, e pelos analistas. Finalmente, a dissertação descreve algumas práticas que todo gerente de marketing na industria de alta tecnologia deve considerar quando adotando MPM. As sugestões são gerais, mas devem familiarizar o leitor com as informações precisas para habilitar processos e rigor na sua organização com respeito a MPM.

The brazilian education quality index (Ideb): measurement and incentives upgrades

The increasing availability of social statistics in Latin America opens new possibilities in terms of accountability and incentive mechanisms for policy makers. This paper addresses these issues within the institutional context of the Brazilian educational system. We build a theoretical model based on the theory of incentives to analyze the role of the recently launched Basic Education Development Index (Ideb) in the provision of incentives at the sub-national level. The first result is to demonstrate that an education target system has the potential to improve the allocation of resources to education through conditional transfers to municipalities and schools. Second, we analyze the local government’s decision about how to allocate its education budget when seeking to accomplish the different objectives contemplated by the index, which involves the interaction between its two components, average proficiency and the passing rate. We discuss as well policy issues concerning the implementation of the synthetic education index in the light of this model arguing that there is room for improving the Ideb’s methodology itself. In addition, we analyze the desirable properties of an ideal education index and we argue in favor of an ex-post relative learning evaluation system for different municipalities (schools) based on the value added across different grades

The role of venture capitalists in the identification and measurement of intangible assets

The increase in the importance of intangibles in business competitiveness has made investment selection more challenging to investors that, under high information asymmetry, tend to charge higher premiums to provide capital or simply deny it. Private Equity and Venture Capital (PE/VC) organizations developed contemporarily with the increase in the relevance of intangible assets in the economy. They form a specialized breed of financial intermediaries that are better prepared to deal with information asymmetry. This paper is the result of ten interviews with PE/VC organizations in Brazil. Its objective is to describe the selection process, criteria and indicators used by these organizations to identify and measure intangible assets, as well as the methods used to valuate prospective investments. Results show that PE/VC organizations rely on sophisticated methods to assess investment proposals, with specific criteria and indicators to assess the main classes of intangible assets. However, no value is given to these assets individually. The information gathered is used to understand the sources of cash flows and risks, which are then combined by discounted cash flow methods to estimate firm's value. Due to PE/VC organizations extensive experience with innovative Small and Medium-sized Enterprises (SMEs), we believe that shedding light on how PE/VC organizations deal with intangible assets brings important insights to the intangible assets debate.