Electrochemical, Spectrophotometric and Liquid-Chromatographic Approaches for Analysis of Tropical Disease Drugs

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Analytical multikinks in smooth potentials

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Evaluating the equilibrium association constant between artinM lectin and myeloid leukemia cells by impedimetric and piezoelectric label free approaches

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

GIS-based analytical tools for transport planning: spatial regression models for transportation demand forecast

Considering the importance of spatial issues in transport planning, the main objective of this study was to analyze the results obtained from different approaches of spatial regression models. In the case of spatial autocorrelation, spatial dependence patterns should be incorporated in the models, since that dependence may affect the predictive power of these models. The results obtained with the spatial regression models were also compared with the results of a multiple linear regression model that is typically used in trips generation estimations. The findings support the hypothesis that the inclusion of spatial effects in regression models is important, since the best results were obtained with alternative models (spatial regression models or the ones with spatial variables included). This was observed in a case study carried out in the city of Porto Alegre, in the state of Rio Grande do Sul, Brazil, in the stages of specification and calibration of the models, with two distinct datasets.

Different approaches for dealing with rare variants in family-based genetic studies: application of a Genetic Analysis Workshop 17 problem

Rare variants are becoming the new candidates in the search for genetic variants that predispose individuals to a phenotype of interest. Their low prevalence in a population requires the development of dedicated detection and analytical methods. A family-based approach could greatly enhance their detection and interpretation because rare variants are nearly family specific. In this report, we test several distinct approaches for analyzing the information provided by rare and common variants and how they can be effectively used to pinpoint putative candidate genes for follow-up studies. The analyses were performed on the mini-exome data set provided by Genetic Analysis Workshop 17. Eight approaches were tested, four using the trait’s heritability estimates and four using QTDT models. These methods had their sensitivity, specificity, and positive and negative predictive values compared in light of the simulation parameters. Our results highlight important limitations of current methods to deal with rare and common variants, all methods presented a reduced specificity and, consequently, prone to false positive associations. Methods analyzing common variants information showed an enhanced sensibility when compared to rare variants methods. Furthermore, our limited knowledge of the use of biological databases for gene annotations, possibly for use as covariates in regression models, imposes a barrier to further research.

Biofuels Sustainability Certification Schemes: Challenges, Feasibility and Possible Approaches

The focus of this research is to develop and apply an analytical framework for evaluating the effectiveness and practicability of sustainability certification schemes for biofuels, especially in a developing country’s perspective. The main question that drives the research analysis is “Which are the main elements of and how to develop sustainability certification schemes that would be effective and practicable in certifying the contribution of biofuels in meeting the goals Governments and other stakeholders have set up?”. Biofuels have been identified as a promising tool to reach a variety of goals: climate change protection, energy security, agriculture development, and, especially in developing countries, economic development. Once the goals have been identified, and ambitious mandatory targets for biofuels use agreed at national level, concerns have been raised by the scientific community on the negative externalities that biofuels production and use can have at environment, social and economic level. Therefore certification schemes have been recognized as necessary processes to measure these externalities, and examples of such schemes are in effect, or are in a negotiating phase, both at mandatory and voluntary levels. The research focus has emerged by the concern that the ongoing examples are very demanding in terms of compliance, both for those that are subject to certification and those that have to certify, on the quantity and quality of information to be reported. A certification system, for reasons linked to costs, lack of expertise, inadequate infrastructure, absence of an administrative and legislative support, can represent an intensive burden and can act as a serious impediment for the industrial and agriculture development of developing countries, going against the principle of equity and level playing field. While this research recognizes the importance of comprehensiveness and ambition in designing an important tool for the measurement of sustainability effects of biofuels production and use, it stresses the need to focus on the effectiveness and practicability of this tool in measuring the compliance with the goal. This research that falls under the rationale of the Sustainability Science Program housed at Harvard Kennedy School, has as main objective to close the gap between the research and policy makers worlds in the field of sustainability certification schemes for biofuels.

Collective effects for the LHC injectors: non-ultrarelativistic approaches

The upgrade of the CERN accelerator complex has been planned in order to further increase the LHC performances in exploring new physics frontiers. One of the main limitations to the upgrade is represented by the collective instabilities. These are intensity dependent phenomena triggered by electromagnetic fields excited by the interaction of the beam with its surrounding. These fields are represented via wake fields in time domain or impedances in frequency domain. Impedances are usually studied assuming ultrarelativistic bunches while we mainly explored low and medium energy regimes in the LHC injector chain. In a non-ultrarelativistic framework we carried out a complete study of the impedance structure of the PSB which accelerates proton bunches up to 1.4 GeV. We measured the imaginary part of the impedance which creates betatron tune shift. We introduced a parabolic bunch model which together with dedicated measurements allowed us to point to the resistive wall impedance as the source of one of the main PSB instability. These results are particularly useful for the design of efficient transverse instability dampers. We developed a macroparticle code to study the effect of the space charge on intensity dependent instabilities. Carrying out the analysis of the bunch modes we proved that the damping effects caused by the space charge, which has been modelled with semi-analytical method and using symplectic high order schemes, can increase the bunch intensity threshold. Numerical libraries have been also developed in order to study, via numerical simulations of the bunches, the impedance of the whole CERN accelerator complex. On a different note, the experiment CNGS at CERN, requires high-intensity beams. We calculated the interpolating Hamiltonian of the beam for highly non-linear lattices. These calculations provide the ground for theoretical and numerical studies aiming to improve the CNGS beam extraction from the PS to the SPS.

Development of new analytical procedures aimet at the characterization of artistic samples

In this thesis, new advances in the development of spectroscopic based methods for the characterization of heritage materials have been achieved. As concern FTIR spectroscopy new approaches aimed at exploiting near and far IR region for the characterization of inorganic or organic materials have been tested. Paint cross-section have been analysed by FTIR spectroscopy in the NIR range and an “ad hoc” chemometric approach has been developed for the elaboration of hyperspectral maps. Moreover, a new method for the characterization of calcite based on the use of grinding curves has been set up both in MIR and in FAR region. Indeed, calcite is a material widely applied in cultural heritage, and this spectroscopic approach is an efficient and rapid tool to distinguish between different calcite samples. Different enhanced vibrational techniques for the characterisation of dyed fibres have been tested. First a SEIRA (Surface Enhanced Infra-Red Absorption) protocol has been optimised allowing the analysis of colorant micro-extracts thanks to the enhancement produced by the addition of gold nanoparticles. These preliminary studies permitted to identify a new enhanced FTIR method, named ATR/RAIRS, which allowed to reach lower detection limits. Regarding Raman microscopy, the research followed two lines, which have in common the aim of avoiding the use of colloidal solutions. AgI based supports obtained after deposition on a gold-coated glass slides have been developed and tested spotting colorant solutions. A SERS spectrum can be obtained thanks to the photoreduction, which the laser may induce on the silver salt. Moreover, these supports can be used for the TLC separation of a mixture of colorants and the analyses by means of both Raman/SERS and ATR-RAIRS can be successfully reached. Finally, a photoreduction method for the “on fiber” analysis of colorant without the need of any extraction have been optimised.

Proposing new approaches for dating young volcanic eruptions by luminescence methods

The application of luminescence dating to young volcanic sediments has been first investigated over three decades ago, but it was only with the technical innovations of the last decade that such analyses became viable. While current analytical procedures show promise for dating late Quaternary volcanic events, most efforts have been aimed at unconsolidated volcanic tephra. Investigations into direct dating of lava flows or of non-heated volcanoclastics like phreatic explosion layers, however, remain scarce. These volcanic deposits are of common occurrence and represent important chrono- and volcanostratigraphic markers. Their age determination is therefore of great importance in volcanologic, tectonic, geomorphological and climate studies. In this article, we propose the use of phreatic explosion deposits and xenolithic inclusions in lava flows as target materials for luminescence dating applications. The main focus is on the crucial criterion whether it is probable that such materials experience complete luminescence signal resetting during the volcanic event to be dated. This is argued based on the findings from existing literature, model calculations and laboratory tests.

INVESTIGATION OF AIR JIGGING AND AIR CLASSIFICATION TO RECOVER METALLIC PARTICLES FROM ANALYTICAL SAMPLES

Analyzing “nuggety” gold samples commonly produces erratic fire assay results, due to random inclusion or exclusion of coarse gold in analytical samples. Preconcentrating gold samples might allow the nuggets to be concentrated and fire assayed separately. In this investigation synthetic gold samples were made using similar density tungsten powder and silica, and were preconcentrated using two approaches: an air jig and an air classifier. Current analytical gold sampling method is time and labor intensive and our aim is to design a set-up for rapid testing. It was observed that the preliminary air classifier design showed more promise than the air jig in terms of control over mineral recovery and preconcentrating bulk ore sub-samples. Hence the air classifier was modified with the goal of producing 10-30 grams samples aiming to capture all of the high density metallic particles, tungsten in this case. Effects of air velocity and feed rate on the recovery of tungsten from synthetic tungsten-silica mixtures were studied. The air classifier achieved optimal high density metal recovery of 97.7% at an air velocity of 0.72 m/s and feed rate of 160 g/min. Effects of density on classification were investigated by using iron as the dense metal instead of tungsten and the recovery was seen to drop from 96.13% to 20.82%. Preliminary investigations suggest that preconcentration of gold samples is feasible using the laboratory designed air classifier.

Analytical form of the Probability Density Function of travel times in rectangular zone with Tchebyshev’s metric

Geometrical dependencies are being researched for analytical representation of the probability density function (pdf) for the travel time between a random, and a known or another random point in Tchebyshev’s metric. In the most popular case - a rectangular area of service - the pdf of this random variable depends directly on the position of the server. Two approaches have been introduced for the exact analytical calculation of the pdf: Ad-hoc approach – useful for a ‘manual’ solving of a specific case; by superposition – an algorithmic approach for the general case. The main concept of each approach is explained, and a short comparison is done to prove the faithfulness.

Territorial approaches for rural development in Latin America : a case study in Chile

Una reciente transición en el campo del desarrollo rural es el movimiento desde un enfoque reducido del sector agrícola hasta uno que adopta una visión territorial más amplia. Este pasaje intenta interpretar las interacciones entre los mundos urbano y rural de una manera más comprensiva. Esta perspectiva teórica relativamente nueva interesa particularmente a los académicos y los políticos en los países latinoamericanos donde, a partir de la mitad de los años noventa, el concepto de una nueva ruralidad se ha visto como la fuente de un nuevo enfoque para el desarrollo rural. Por lo tanto, el propósito teórico de esta investigación es explicitar los indicadores analíticos del nuevo enfoque de la ruralidad en América Latina e identificar las diferencias entre los acercamientos sectoriales y territoriales, considerando los aspectos socio-económicos, institucionales y medioambientales involucrados. La transición del enfoque sectorial a uno territorial significa también, desde un punto de vista operativo, el reconocimiento de la existencia de áreas homogéneas a partir de las cuales pueden proponerse estrategias de desarrollo rural. El propósito operativo de esta investigación consiste en proponer una metodología para identificar estas áreas con una aplicación a la Región del Maule en Chile. La conclusión subraya algunos elementos críticos que se deben considerar en la definición de estrategias del desarrollo rural territorial.

Evaluation of the BEASY program using linear and piecewise linear approaches for the boundary conditions

The boundary element method (BEM) was used to study galvanic corrosion using linear and logarithmic boundary conditions. The linear boundary condition was implemented by using the linear approach and the piecewise linear approach. The logarithmic boundary condition was implemented by the piecewise linear approach. The calculated potential and current density distribution were compared with the prior analytical results. For the linear boundary condition, the BEASY program using the linear approach and the piecewise linear approach gave accurate predictions of the potential and the galvanic current density distributions for varied electrolyte conditions, various film thicknesses, various electrolyte conductivities and various area ratio of anode/cathode. The 50-point piecewise linear method could be used with both linear and logarithmic polarization curves.

Managing healthcare performance in analytical framework

Purpose – The purpose of the paper is to develop an integrated framework for performance management of healthcare services. Design/methodology/approach – This study develops a performance management framework for healthcare services using a combined analytic hierarchy process (AHP) and logical framework (LOGFRAME). The framework is then applied to the intensive care units of three different hospitals in developing nations. Numerous focus group discussions were undertaken, involving experts from the specific area under investigation. Findings – The study reveals that a combination of outcome, structure and process-based critical success factors and a combined AHP and LOGFRAME-based performance management framework helps manage performance of healthcare services. Practical implications – The proposed framework could be practiced in hospital-based healthcare services. Originality/value – The conventional approaches to healthcare performance management are either outcome-based or process-based, which cannot reveal improvement measures appropriately in order to assure superior performance. Additionally, they lack planning, implementing and evaluating improvement projects that are identified from performance measurement. This study presents an integrated approach to performance measurement and implementing framework of improvement projects.

Multilevel analyses in marketing research:differentiating analytical outcomes

Marketing scholars are increasingly recognizing the importance of investigating phenomena at multiple levels. However, the analyses methods that are currently dominant within marketing may not be appropriate to dealing with multilevel or nested data structures. We identify the state of contemporary multilevel marketing research, finding that typical empirical approaches within marketing research may be less effective at explicitly taking account of multilevel data structures than those in other organizational disciplines. A Monte Carlo simulation, based on results from a previously published marketing study, demonstrates that different approaches to analysis of the same data can result in very different results (both in terms of power and effect size). The implication is that marketing scholars should be cautious when analyzing multilevel or other grouped data, and we provide a discussion and introduction to the use of hierarchical linear modeling for this purpose.