Rotational self-diffusion in suspensions of charged particles: Revised Beenakker-Mazur and Pairwise Additivity methods versus numerical simulations

To the present day, the Beenakker-Mazur (BM) method is the most comprehensive statistical physics approach to the calculation of short-time transport properties of colloidal suspensions. A revised version of the BM method with an improved treatment of hydrodynamic interactions is presented and evaluated regarding the rotational short-time self-diffusion coefficient, $D^r$ , of suspensions of charged particles interacting by a hard-sphere plus screened Coulomb (Yukawa) pair potential. To assess the accuracy of the method, elaborate simulations of $D^r$ have been performed, covering a broad range of interaction parameters and particle concentrations. The revised BM method is compared in addition with results by a simplifying pairwise additivity (PA) method in which the hydrodynamic interactions are treated on a two-body level. The static pair correlation functions re- quired as input to both theoretical methods are calculated using the Rogers-Young integral equation scheme. While the revised BM method reproduces the general trends of the simulation results, it systematically and significantly underestimates the rotational diffusion coefficient. The PA method agrees well with the simulation data at lower volume fractions, but at higher concentrations $D^r$ is likewise underestimated. For a fixed value of the pair potential at mean particle distance comparable to the thermal energy, $D^r$ increases strongly with increasing Yukawa potential screening parameter.Comment: 24 pages, 13 figure

Uso de séries temporais NDVI do MODIS para mapeamento da cobertura vegetal natural e exótica em uma região de transição cerrado-caatinga

Dissertação (mestrado)—Universidade de Brasília, Instituto de Humanas, Departamento de Geografia, 2015.O acompanhamento orbital da flora brasileira tem como marco inicial o projeto Radam na década de 1970. Na época foram utilizados dados do Side-Looking Airborne Radar (SLAR). Outros programas visando conhecer e monitorar o estado de conservação dos biomas do Brasil foram conduzidos nos últimos anos. Cita-se dentre eles o Programa de Cálculo de Desflorestamento da Amazônia (PRODES), a Detecção em Tempo Real (DETER), o Projeto de Conservação e Utilização Sustentável da Diversidade Biológica Brasileira (PROBIO) e o Projeto de Monitoramento do Desmatamento nos Biomas Brasileiros por Satélite (PMDBBS). Além dessas iniciativas governamentais, pesquisas vêm sendo conduzidas por instituições de cunho acadêmico-científico nacionais e internacionais. Todavia, a maioria dos esforços até então conduzidos ou foram orientados ao ecossistema Amazônico ou lançaram mão de técnicas apoiadas em imagens monotemporais, cuja resolução espaço-temporal não é compatível com a atual dinâmica de mudança da paisagem. Diante dessa realidade, desenvolveu-se este trabalho visando estudar uma região de transição de ecossistemas semiáridos (Cerrado-Caatinga), localizada no norte do estado de Minas Gerais e sudoeste da Bahia. Trata-se de um local de biodiversidade riquíssima, composta por uma flora complexa e que ainda não foi muito bem estudada. Sua paisagem começa agora a sofrer alterações por conta do crescimento significativo de atividades antrópicas ligadas à agricultura, alavancadas pela concretização de grandes projetos de irrigação criados entre as décadas de 1970 e 1990. Para atingir tal objetivo, foi aplicado um conjunto de metodologias que envolveu: o uso de séries temporais NDVI-MODIS, compreendendo o período de 2011 a 2013, oriundas do produto MOD09Q1; das técnicas filtragem de mediana e Savitzky-Golay; seleção de assinaturas temporais de classes de uso da terra e cobertura vegetal; e classificação das séries temporais através dos algoritmos de similaridade e distância Spectral Angle Mapper (SAM), Spectral Correlation Mapper (SCM) e Euclidian Distance Measure (ED). Os melhores resultados foram obtidos com o uso do classificador ED sobre a série temporal NDVI-MODIS, alcançando índices de Exatidão Global e Kappa, superiores a 82% e 0,75. Entretanto, mais estudos devem ser feios visando à distinção das fitofisionomias de porte arbustivo–herbáceo do domínio Cerrado, bem como das lavouras cultivadas nas propriedades agrícolas familiares, presentes em grande número à margem esquerda do rio São Francisco.The orbital monitoring of Brazilian flora began in the 1970s with Radam project, when were used data of the Side-Looking Airborne Radar (SLAR). Other programs were conducted in order to know and monitor the conservation status of Brazil’s biomes. The Programa de Cálculo de Desflorestamento da Amazônia (PRODES), the Detecção em Tempo Real (DETER), the Projeto de Conservação e Utilização Sustentável da Diversidade Biológica Brasileira (PROBIO) and Projeto de Monitoramento do Desmatamento nos Biomas Brasileiros por Satélite (PMDBBS) were some such initiatives. In addition to government actions, research is being conducted by institutions of national and international academic and scientific nature. However, most efforts were directed to the Amazon ecosystem or used techniques supported by monotemporal images, resolution space-times is not compatible with the current dynamics of change of the landscape. Given this reality, we developed this work aiming to study a transition region of semi-arid ecosystems (Cerrado-Caatinga), located in the north of Minas Gerais and Bahia southwest, Brazil. This place has rich biodiversity, consisting of a complex flora and that has not been well studied. Its landscape begins to undergo changes due to significant growth of human activities related to agriculture, leveraged by the realization of major irrigation projects created between the 1970s and 1990s. Thus, we used the following method: use of NDVI-MODIS time-series from 2011 to 2013, deriving from the MOD09Q1 product; use of median and Savitzky-Golay filters; selection of temporal-signature references of land use and vegetation cover and use of classifiers similarity and distance Spectral Angle Mapper (SAM), Spectral Correlation Mapper (SCM) and Euclidian Distance Measure (ED).The results were satisfactory especially when using the classifier ED on time series NDVI-MODIS, reaching levels of agreement, Global Accuracy and Kappa, more than 82% and 0.75. However, more studies should be made to identify the shrub and herbaceous vegetation types of the Cerrado biome and the crops grown on farms of small extent, present in large numbers on the left of São Francisco river

Child abandonment and illegitimacy in the Island of São Jorge (Azores-Portugal).

VII Expedição Científica do Departamento de Biologia - São Jorge e Topo - 1992.During the 1992 Scientific Expedition to São Jorge, parish registers were consulted referring to some villages of the district of Velas, according to the following described: Baptisms (1875-1900)- Variables include date of birth, place of birth, legitimacy/illegitimacy (Velas; Santo Amaro). Marriages (1876-l900)- Variables include place of birth of the couple, residency, age, marital status, occupation and consanguinity (Urzelina-146; Velas-279; Santo Amaro-148; Norte Grande-290; Manadas-136). Deaths (1876-1900)- Variables include date of burial, sex, age, marital status and legitimacy (Santo Amaro; Velas). For purposes of this report, only data referring to the baptisms were dealt with, giving particular emphasize to the variable of illegitimacy

Effect of Chemically Modified Banana Fibers on the Mechanical Properties of Poly-Dimethyl-Siloxane-Based Composites

The study presents the mechanical properties of polymer-based composites reinforced with chemically modified banana fibers, by alkalization in different concentrations of sodium hydroxide (NaOH). The fiber weight fraction has a great effect on the mechanical properties of the composites. Stiff composites were obtained at 6 wt% fiber fractions with Young’s modulus of 254.00 ±12.70 MPa. Moreover, the yield strength was 35.70 ±1.79 MPa at 6 wt% fiber fractions. However, the ultimate tensile strength (UTS) and toughness of the composites were obtained at 5 wt% fiber fractions. Statistical analyses were used to ascertain the significant different on the mechanical properties of the fibers and composites. The implication of the results is then discussed for potential applications of PDMS-based composites reinforced with chemically modified banana fibers

Perception of the meaning of the caretaker's function for a group of nurses is caretakers: convergences are divergences in its speeches

This study review the of role the caretaker at the pediatric unit while the child is in hospital. The opinions of caretaker and nurses were surveyed as for the role that the participating family member would have during their stay along with the child in hospital. Data were gathered between April and June 1997 in units allowing for children to stay together with caretaker, at state hospitals. The interviews with the groups were separated by menu of the stafement analysis, based on the studies by COSTA (1992), and FRIEDMAN (1986), which allowed us to determine six categories: Security & Protection, Caretaking, Recovery, Knowledge, Supervisionn and Guidance, which in turn allowed us to study, although in a modest fashion, the agrements and disagreements regarding how our interviewews perceive the role of the caretaker.Este estudo discute a função do cuidador na unidade pediátrica durante a internação da criança. Foram levantadas as opiniões de cuidadores e enfermeiras a respeito da função que caberia ao familiar acompanhante durante sua permanência junto a criança hospitalizada. Os dados foram colhidos no período de abril junho de 1997 em unidades de internação conjunta pediátrica de um hospital da rede plública estadual. As enfermeiras com os grupos foram decompostas por meio da analise de discurso, baseado nos estudos de COSTA(1992); FRIENDMAN (1980), que nos possibilitou chegar a seis categorias: Segurança e Proteção, Cuidar, Recuperação, conhecimento, Supervisão e Orientação, que nos permitiu uma explanarão das convergências e divergências nas percepções dos nossos entrevistados sobre a função do cuidador.UNIFESP-EPMUniversidade cidade de São PauloUSP Escola de EnfermagemUNIFESP, EPMSciEL

Rotational and translational self-diffusion in concentrated suspensions of permeable particles

In our recent work on concentrated suspensions of uniformly porous colloidal spheres with excluded volume interactions, a variety of short-time dynamic properties were calculated, except for the rotational self-diffusion coefficient. This missing quantity is included in the present paper. Using a precise hydrodynamic force multipole simulation method, the rotational self-diffusion coefficient is evaluated for concentrated suspensions of permeable particles. Results are presented for particle volume fractions up to 45%, and for a wide range of permeability values. From the simulation results and earlier results for the first-order virial coefficient, we find that the rotational self-diffusion coefficient of permeable spheres can be scaled to the corresponding coefficient of impermeable particles of the same size. We also show that a similar scaling applies to the translational self-diffusion coefficient considered earlier. From the scaling relations, accurate analytic approximations for the rotational and translational self-diffusion coefficients in concentrated systems are obtained, useful to the experimental analysis of permeable-particle diffusion. The simulation results for rotational diffusion of permeable particles are used to show that a generalized Stokes-Einstein-Debye relation between rotational self-diffusion coefficient and high-frequency viscosity is not satisfied.Comment: 4 figure

Evolution of ochratoxin A content from must to wine in Port wine microvinification

To study the evolution of ochratoxin A (OTA) content from must to wine during the making of Port Wine, grapes from the five most common varieties of Port Wine were harvested and combined in equal percentages in order to perform microvinifications. Three sets of assays were studied: a blank (A), where the most common Port Wine-making process was used; in the second (B), a solution of OTA was added to the initial must; in the third (C), the grapes were aspersed with an inoculating solution of OTA-producing fungi. Samples were collected, in duplicate, on four different occasions throughout the process. The influence of the addition of SO_2 to the must was also assessed in each set. The quantification of OTA was based on the standard reference method for wines (European Standard prEN 14133), which includes clean-up via immunoaffinity columns and HPLC with fluorescence detection. The limits of detection were 0.076 μg/l for wine and 0.114 μg/l for must. The method was validated by assessing the precision, accuracy and by obtaining an estimate of the global uncertainty. Overall, the levels of OTA observed during the vinifications dropped by up to 92%, and no grapes used in this work were contaminated naturally.The authors wish to thank the support of the INIAP—Instituto Nacional de Investigação Agrária e das Pescas (Portugal), through the Program AGRO, Medida 8.1, and all the personnel and facilities at the Centro de Estudos Vitivinícolas do Douro (Peso da Régua, Portugal) and the Instituto dos Vinhos do Douro e Porto (Porto, Portugal)

Desenvolvimento de Jogos Educativos na plataforma APEX : O Jogo da Asma

National audienceA plataforma APEX foi desenvolvida para a prototipagem de ambientes de computação ubíqua. Neste artigo exploramos a sua aplicabilidade ao desenvolvimento de Jogos Sérios. Ou seja, jogos que para além de uma componente lúdica, possuem uma componente instrutiva e formativa. Em concreto, descrevemos o Jogo da Asma. Um jogo que pretende chamar a atenção das crianças para os factores causadores de ataques de asma, bem como transmitir conhecimento sobre como os evitar. Para além de se descrever o jogo, descrevem-se os resultados de um estudo em que se procurou avaliar quer a viabilidade da utilização da plataforma na criação de jogos sérios, quer a usabilidade do próprio jogo

Avaliação de ambientes ubíquos na plataforma APEX

Este artigo descreve a avaliação de um ambiente ubíquo utilizando a APEX, uma plataforma de prototipagem rápida de ambientes ubíquos que permite que os utilizadores naveguem num mundo virtual, podendo experimentar muitas das funcionalidades da solução e do design proposto.Este trabalho é financiado por Fundos FEDER através do Programa Operacional Factores de Competitividade – COMPETE e por Fundos Nacionais através da FCT – Fundação para a Ciência e a Tecnologia no âmbito do projecto FCOMP-01-0124-FEDER-015095

Diffusion, sedimentation, and rheology of concentrated suspensions of core-shell particles

Short-time dynamic properties of concentrated suspensions of colloidal core-shell particles are studied using a precise force multipole method which accounts for many-particle hydrodynamic interactions. A core-shell particle is composed of a rigid, spherical dry core of radius a surrounded by a uniformly permeable shell of outer radius b and hydrodynamic penetration depth κ(-1). The solvent flow inside the permeable shell is described by the Brinkman-Debye-Bueche equation, and outside the particles by the Stokes equation. The particles are assumed to interact non-hydrodynamically by a hard-sphere no-overlap potential of radius b. Numerical results are presented for the high-frequency shear viscosity, η(∞), sedimentation coefficient, K, and the short-time translational and rotational self-diffusion coefficients, D(t) and D(r). The simulation results cover the full three-parametric fluid-phase space of the composite particle model, with the volume fraction extending up to 0.45, and the whole range of values for κb, and a/b. Many-particle hydrodynamic interaction effects on the transport properties are explored, and the hydrodynamic influence of the core in concentrated systems is discussed. Our simulation results show that for thin or hardly permeable shells, the core-shell systems can be approximated neither by no-shell nor by no-core models. However, one of our findings is that for κ(b - a) ≳ 5, the core is practically not sensed any more by the weakly penetrating fluid. This result is explained using an asymptotic analysis of the scattering coefficients entering into the multipole method of solving the Stokes equations. We show that in most cases, the influence of the core grows only weakly with increasing concentration