Combining nonthermal technologies to control foodborne microorganisms

Novel nonthermal processes, such as high hydrostatic pressure (HHP), pulsed electric fields (PEFs), ionizing radiation and ultrasonication, are able to inactivate microorganisms at ambient or sublethal temperatures. Many of these processes require very high treatment intensities, however, to achieve adequate microbial destruction in low-acid foods. Combining nonthermal processes with conventional preservation methods enhances their antimicrobial effect so that lower process intensities can be used. Combining two or more nonthermal processes can also enhance microbial inactivation and allow the use of lower individual treatment intensities. For conventional preservation treatments, optimal microbial control is achieved through the hurdle concept, with synergistic effects resulting from different components of the microbial cell being targeted simultaneously. The mechanisms of inactivation by nonthermal processes are still unclear; thus, the bases of synergistic combinations remain speculative. This paper reviews literature on the antimicrobial efficiencies of nonthermal processes combined with conventional and novel nonthermal technologies. Where possible, the proposed mechanisms of synergy is mentioned. (C) 2003 Elsevier Science B.V. All rights reserved.

Surface diffusion of strongly adsorbing vapors in activated carbon by a differential permeation method

Conventional methods to determine surface diffusion of adsorbed molecules are proven to be inadequate for strongly adsorbing vapors on activated carbon. Knudsen diffusion permeability (B-k) for strongly adsorbing vapors cannot be directly estimated from that of inert gases such as helium. In this paper three models are considered to elucidate the mechanism of surface diffusion in activated carbon. The transport mechanism in all three models is a combination of Knudsen diffusion, viscous flow and surface diffusion. The collision reflection factor f (which is the fraction of molecules undergoing collision to the solid surface over reflection from the surface) of the Knudsen diffusivity is assumed to be a function of loading. It was found to be 1.79 in the limit of zero loading, and decreases as loading increases. The surface diffusion permeability increases sharply at very low pressures and then starts to decrease after it has reached a maximum (B(mum)s) at a threshold pressure. The initial rapid increase in the total permeability is mainly attributed to surface diffusion. Interestingly the B(mum)s for all adsorbates appear at the same volumetric adsorbed phase concentration, suggesting that the volume of adsorbed molecules may play an important role in the surface diffusion mechanism in activated carbon. (C) 2003 Elsevier Ltd. All rights reserved.

A new wavelet-based adaptive method for solving population balance equations

A new wavelet-based adaptive framework for solving population balance equations (PBEs) is proposed in this work. The technique is general, powerful and efficient without the need for prior assumptions about the characteristics of the processes. Because there are steeply varying number densities across a size range, a new strategy is developed to select the optimal order of resolution and the collocation points based on an interpolating wavelet transform (IWT). The proposed technique has been tested for size-independent agglomeration, agglomeration with a linear summation kernel and agglomeration with a nonlinear kernel. In all cases, the predicted and analytical particle size distributions (PSDs) are in excellent agreement. Further work on the solution of the general population balance equations with nucleation, growth and agglomeration and the solution of steady-state population balance equations will be presented in this framework. (C) 2002 Elsevier Science B.V. All rights reserved.

Method for determining the shear stress in cylindrical systems

We develop a method for determining the elements of the pressure tensor at a radius r in a cylindrically symmetric system, analogous to the so-called method of planes used in planar systems [B. D. Todd, Denis J. Evans, and Peter J. Daivis, Phys. Rev. E 52, 1627 (1995)]. We demonstrate its application in determining the radial shear stress dependence during molecular dynamics simulations of the forced flow of methane in cylindrical silica mesopores. Such expressions are useful for the examination of constitutive relations in the context of transport in confined systems.

Adapted Gaussian basis sets for atoms from Li through Xe generated with the generator coordinate Hartree-Fock method

Utiliza-se o método coordenada geradora Hartree-Fock para gerar bases Gaussianas adaptadas para os átomos de Li (Z=3) até Xe (Z=54). Neste método, integram-se as equações de Griffin-Hill-Wheeler-Hartree-Fock através da técnica de discretização integral. Comparam-se as funções de ondas geradas neste trabalho com as funções de ondas Roothaan-Hartree-Fock de Clementi e Roetti (1974) e com outros conjuntos de bases relatados na literatura. Para os átomos estudados aqui, os erros em nossas energias totais relativos aos limites numéricos Hartree-Fock são sempre menores que 7,426 milihartree.

Efetividade da participação no legislativo capixaba : um estudo sobre as audiências públicas do orçamento (2007-2014)

Esta pesquisa é um estudo sobre as audiências públicas da Lei Orçamentária Anual (LOA) realizadas pela Assembleia Legislativa do Espírito Santo (ALES) no período de 2007 até 2014. O tema central deste trabalho é a efetividade da participação das audiências, ancorada em duas dimensões: o momento deliberativo e os resultados das audiências. Partimos do pressuposto que, apesar da dificuldade de mensurar efeitos práticos, as Instituições Participativas, tais como as audiências da LOA, atuam em um propósito de aprofundamento da democracia, especialmente na destinação de recursos de acordo com demandas da sociedade. Dentro desse cenário, o presente trabalho analisa elementos constituintes das audiências (perfil dos legisladores, desenho institucional, perfil dos participantes, influência do poder Executivo e as emendas parlamentares) para avaliar a efetividade da participação. Para esta análise, utilizamos uma abordagem multimétodo com a combinação de três ferramentas de pesquisa: análise documental (relatórios da LOA, legislações e vídeos das audiências públicas), survey (aplicado a participantes das audiências de 2014) e entrevista semiestruturada (com os parlamentares que fazem parte da Comissão de Finanças). A análise aponta para a baixa efetividade das audiências a partir da combinação de vários fatores, entre eles a baixa institucionalização, a influência do poder Executivo no processo a partir de sua relação com os parlamentares e o uso das emendas parlamentares como estratégia eleitoral.

The influence of the dispersion method on the electrical properties of vapor-grown carbon nanofiber/epoxy composites

The influence of the dispersion of vapor-grown carbon nanofibers (VGCNF) on the electrical properties of VGCNF/ Epoxy composites has been studied. A homogenous dispersion of the VGCNF does not imply better electrical properties. In fact, it is demonstrated that the most simple of the tested dispersion methods results in higher conductivity, since the presence of well-distributed nanofiber clusters appears to be a key factor for increasing composite conductivity.

Combining Formal Methods and Functional Strategies Regarding the Reverse Engineering of Interactive Applications

Abstract. Graphical user interfaces (GUIs) make software easy to use by providing the user with visual controls. Therefore, correctness of GUI’s code is essential to the correct execution of the overall software. Models can help in the evaluation of interactive applications by allowing designers to concentrate on its more important aspects. This paper describes our approach to reverse engineer an abstract model of a user interface directly from the GUI’s legacy code. We also present results from a case study. These results are encouraging and give evidence that the goal of reverse engineering user interfaces can be met with more work on this technique.

Multiple centroid method to evaluate the adaptability of alfalfa genotypes

This study aimed to evaluate the efficiency of multiple centroids to study the adaptability of alfalfa genotypes (Medicago sativa L.). In this method, the genotypes are compared with ideotypes defined by the bissegmented regression model, according to the researcher's interest. Thus, genotype classification is carried out as determined by the objective of the researcher and the proposed recommendation strategy. Despite the great potential of the method, it needs to be evaluated under the biological context (with real data). In this context, we used data on the evaluation of dry matter production of 92 alfalfa cultivars, with 20 cuttings, from an experiment in randomized blocks with two repetitions carried out from November 2004 to June 2006. The multiple centroid method proved efficient for classifying alfalfa genotypes. Moreover, it showed no unambiguous indications and provided that ideotypes were defined according to the researcher's interest, facilitating data interpretation.

A high-throughput screening method for general cytotoxicity part I Chemical toxicity

Foi desenvolvido um método destinado a fazer a triagem rápida e o escalonamento da toxicidade geral exercida por xenobióticos tendo como modelo o Saccharomyces cerevisiae. Para padronizar as condições de experimentação foi estabelecida a relação entre a absorvência a 525 nm e o número de células em suspensão por mililitro de meio de cultura e calculadas uma curva padrão e respectiva equação definidora (Y=6,8219E-08X + 0,0327) Culturas de Saccharomyces cerevisiae em meio completo para leveduras (YPD - 1% de glucose 2%, de peptona 0,5% e extracto de levedura 1%) foram expostas a diferentes concentrações de nicotina e a inibição do crescimento avaliada.

Combining the rational and relational perspectives of electronic trading

Many organisations make extensive use of electronic linkages to facilitate their trading exchanges with partners such as suppliers, distributors and customers. This research explores how the use of inter-organisational systems (IOS) both affects, and is affected by, the relationships between trading partners. In doing this, it brings together two existing but distinct perspectives and literatures; the rational view informed by IOS research, and the behavioural or relationship perspective embodied in inter-organisational relationships (IOR) literature. The research was undertaken in the European paper industry by means of six dyadic case studies. The dyads studied covered both traditional electronic data interchange systems and newer e-marketplace environments. A framework was derived from existing literature that integrates the two perspectives of interest. The framework was used to analyse the case studies undertaken and enabled the inter-relationship between IOS use and IOR to be explained.

An appraisal of the health planning method proposed by the Pan-American Health Organization for Latin America

A brief description of the main features of the health planning technique developed by the "Centro de Estudios del Desarrollo" (CENDES) in Venezuela, and proposed by the Pan-American Health Organization for use in Latin America, is presented. This presentation is followed by an appraisal of the planning method which includes comments both upon its positive aspects and upon its negative points. Comments are also made referring to other recent publications of the WHO/PAHO on health planning. In conclusion, the CENDES technique is considered a health planning method of great potential for use especially in underdeveloped areas, the success of its application depending upon the hability of the health planners to introduce the necessary modifications to adapt to the local circunstamces.