Simulação do processo da absorção do ferro presente em águas de abastecimento da indústria de alimentos

Adsorption processes have been quite effective when removing contaminants from liquid streams, especially in water treatment. This paper aims to present a phenomenological model which describes the process of iron removal by adsorption in a fixed bed column, by using NaY zeolite as adsorbent. The mathematical model considers the resistance to mass transfer inside and outside the adsorbent particle. The Finite Volumes Method was used in the discretization of differential equations that describe the phenomenon, thereby creating a computational code developed from the mathematical modeling. The numerical results obtained by simulation have been compared in order to obtain a good correlation, compared to experimental data in the literature. The formulation of the computational code provides an important tool for the design of adsorptive columns, in which can be dimensioned to industrial scale.Os processos de adsorção têm se mostrado bastante eficientes na remoção de contaminantes em efluentes líquidos, especialmente no tratamento de água. Este trabalho tem por objetivo apresentar um modelo fenomenológico que descreva o processo de remoção do ferro através da adsorção em uma coluna de leito fixo, utilizando-se zeólita NaY como adsorvente. O modelo matemático considera as resistências de transferência de massa interna e externa à partícula do adsorvente. Foi usado Método de Volumes Finitos na discretização das equações diferenciais que descrevem o fenômeno, para então criar um código computacional desenvolvido a partir da modelagem matemática. Foram comparados os resultados numéricos obtidos através da simulação objetivando obter uma boa correlação quando comparados com dados experimentais encontrados na literatura. A formulação do código computacional proporciona o uso de uma ferramenta importante para o dimensionamento de colunas adsortivas, nas quais poderão ser dimensionadas para escala industrial

On the Complex Network Structure of Musical Pieces: Analysis of Some Use Cases from Different Music Genres

This paper focuses on the modeling of musical melodies as networks. Notes of a melody can be treated as nodes of a network. Connections are created whenever notes are played in sequence. We analyze some main tracks coming from different music genres, with melodies played using different musical instruments. We find out that the considered networks are, in general, scale free networks and exhibit the small world property. We measure the main metrics and assess whether these networks can be considered as formed by sub-communities. Outcomes confirm that peculiar features of the tracks can be extracted from this analysis methodology. This approach can have an impact in several multimedia applications such as music didactics, multimedia entertainment, and digital music generation.Comment: accepted to Multimedia Tools and Applications, Springe

Learning health ‘safety’ within non-technical skills interprofessional simulation education: a qualitative study

Background: Healthcare increasingly recognises and focusses on the phenomena of ‘safe practice’ and ‘patient safety.’ Success with non-technical skills (NTS) training in other industries has led to widespread transposition to healthcare education, with communication and teamwork skills central to NTS frameworks. Objective: This study set out to identify how the context of interprofessional simulation learning influences NTS acquisition and development of ‘safety’ amongst learners. Methods: Participants receiving a non-technical skills (NTS) safety focussed training package were invited to take part in a focus group interview which set out to explore communication, teamwork, and the phenomenon of safety in the context of the learning experiences they had within the training programme. The analysis was aligned with a constructivist paradigm and took an interactive methodological approach. The analysis proceeded through three stages, consisting of open, axial, and selective coding, with constant comparisons taking place throughout each phase. Each stage provided categories that could be used to explore the themes of the data. Additionally, to ensure thematic saturation, transcripts of observed simulated learning encounters were then analysed. Results: Six themes were established at the axial coding level, i.e., analytical skills, personal behaviours, communication, teamwork, context, and pedagogy. Underlying these themes, two principal concepts emerged, namely: intergroup contact anxiety – as both a result of and determinant of communication – and teamwork, both of which must be considered in relation to context. These concepts have subsequently been used to propose a framework for NTS learning. Conclusions: This study highlights the role of intergroup contact anxiety and teamwork as factors in NTS behaviour and its dissipation through interprofessional simulation learning. Therefore, this should be a key consideration in NTS education. Future research is needed to consider the role of the affective non-technical attributes of intergroup contact anxiety and teamwork as focuses for education and determinants of safe behaviour

Some Like It Fat: Comparative Ultrastructure of the Embryo in Two Demosponges of the Genus Mycale (Order Poecilosclerida) from Antarctica and the Caribbean

0000-0002-7993-1523© 2015 Riesgo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License [4.0], which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article

Evaluation of rate law approximations in bottom-up kinetic models of metabolism.

BackgroundThe mechanistic description of enzyme kinetics in a dynamic model of metabolism requires specifying the numerical values of a large number of kinetic parameters. The parameterization challenge is often addressed through the use of simplifying approximations to form reaction rate laws with reduced numbers of parameters. Whether such simplified models can reproduce dynamic characteristics of the full system is an important question.ResultsIn this work, we compared the local transient response properties of dynamic models constructed using rate laws with varying levels of approximation. These approximate rate laws were: 1) a Michaelis-Menten rate law with measured enzyme parameters, 2) a Michaelis-Menten rate law with approximated parameters, using the convenience kinetics convention, 3) a thermodynamic rate law resulting from a metabolite saturation assumption, and 4) a pure chemical reaction mass action rate law that removes the role of the enzyme from the reaction kinetics. We utilized in vivo data for the human red blood cell to compare the effect of rate law choices against the backdrop of physiological flux and concentration differences. We found that the Michaelis-Menten rate law with measured enzyme parameters yields an excellent approximation of the full system dynamics, while other assumptions cause greater discrepancies in system dynamic behavior. However, iteratively replacing mechanistic rate laws with approximations resulted in a model that retains a high correlation with the true model behavior. Investigating this consistency, we determined that the order of magnitude differences among fluxes and concentrations in the network were greatly influential on the network dynamics. We further identified reaction features such as thermodynamic reversibility, high substrate concentration, and lack of allosteric regulation, which make certain reactions more suitable for rate law approximations.ConclusionsOverall, our work generally supports the use of approximate rate laws when building large scale kinetic models, due to the key role that physiologically meaningful flux and concentration ranges play in determining network dynamics. However, we also showed that detailed mechanistic models show a clear benefit in prediction accuracy when data is available. The work here should help to provide guidance to future kinetic modeling efforts on the choice of rate law and parameterization approaches

Oscillations and Episodic Memory: Addressing the Synchronization/Desynchronization Conundrum

Brain oscillations are one of the core mechanisms underlying episodic memory. However, while some studies highlight the role of synchronized oscillatory activity, others highlight the role of desynchronized activity. We here describe a framework to resolve this conundrum and integrate these two opposing oscillatory behaviors. Specifically, we argue that the synchronization and desynchronization reflect a division of labor between a hippocampal and a neocortical system, respectively. We describe a novel oscillatory framework that integrates synchronization and desynchronization mechanisms to explain how the two systems interact in the service of episodic memory

Lethality and centrality in protein networks

In this paper we present the first mathematical analysis of the protein interaction network found in the yeast, S. cerevisiae. We show that, (a) the identified protein network display a characteristic scale-free topology that demonstrate striking similarity to the inherent organization of metabolic networks in particular, and to that of robust and error-tolerant networks in general. (b) the likelihood that deletion of an individual gene product will prove lethal for the yeast cell clearly correlates with the number of interactions the protein has, meaning that highly-connected proteins are more likely to prove essential than proteins with low number of links to other proteins. These results suggest that a scale-free architecture is a generic property of cellular networks attributable to universal self-organizing principles of robust and error-tolerant networks and that will likely to represent a generic topology for protein-protein interactions.Comment: See also http:/www.nd.edu/~networks and http:/www.nd.edu/~networks/cel

Systemic properties of metabolic networks lead to an epistasis-based model for heterosis

The genetic and molecular approaches to heterosis usually do not rely on any model of the genotype–phenotype relationship. From the generalization of Kacser and Burns’ biochemical model for dominance and epistasis to networks with several variable enzymes, we hypothesized that metabolic heterosis could be observed because the response of the flux towards enzyme activities and/or concentrations follows a multi-dimensional hyperbolic-like relationship. To corroborate this, we used the values of systemic parameters accounting for the kinetic behaviour of four enzymes of the upstream part of glycolysis, and simulated genetic variability by varying in silico enzyme concentrations. Then we “crossed” virtual parents to get 1,000 hybrids, and showed that best-parent heterosis was frequently observed. The decomposition of the flux value into genetic effects, with the help of a novel multilocus epistasis index, revealed that antagonistic additive-by-additive epistasis effects play the major role in this framework of the genotype–phenotype relationship. This result is consistent with various observations in quantitative and evolutionary genetics, and provides a model unifying the genetic effects underlying heterosis

Importância do diagnóstico fetal de atresia de esôfago para a suspeição clínica de síndrome de Edwards

ResumoNosso objetivo é relatar um feto cuja confirmação diagnóstica de atresia de esôfago através da ressonância nuclear magnética (RNM) levou à suspeita de síndrome de Edwards. A gestante apresentava 28 anos e veio inicialmente à consulta na medicina fetal com 24 semanas de gravidez. Possuía ultrassom fetal com polidrâmnio, artéria umbilical única e não visualização da bolha gástrica. A RNM fetal evidenciou a presença de uma estrutura similar a uma bolsa dilatada ao nível torácico, na topografia da porção proximal do esôfago, o que confirmou o diagnóstico de atresia de esôfago. Neste momento, suspeitou-se do diagnóstico de cromossomopatia, em especial, de síndrome de Edwards. Contudo, o exame de cariótipo não pôde ser realizado no momento. A ecocardiografia fetal de pouco antes do nascimento mostrou uma tetralogia de Fallot. A criança nasceu de parto cesáreo, com 33 semanas de gestação, pesando 1460 g. Observou-se na sua avaliação a presença de dismorfias como camptodactilia dos dedos das mãos e calcâneos proeminentes. A avaliação cariotípica confirmou a suspeita de síndrome de Edwards. Os exames complementares também confirmaram a presença de atresia de esôfago com fístula traqueoesofágica. A síndrome de Edwards é uma anormalidade cromossômica relativamente comum caracterizada por um espectro clínico bastante amplo e uma limitada sobrevida. A RNM fetal, por sua vez, tem o potencial de complementar a avaliação realizada pelo US na elucidação de algumas malformações maiores fetais, tal como a atresia de esôfago. Estas possuem o potencial de serem marcadores para anormalidades cromossômicas, tal como a síndrome de Edwards

A Produção Acadêmica no Brasil sobre Ciência da Informação: um estudo a partir da Teoria do Conhecimento de Habermas

Information Science has searched for elements from other sciences in order to expand its understanding of its main object of study: information. It is important to analyze how the process of theoretical construction has been taking place. Our objective is to evaluate the condition of Information Science in Brazil using proceedings from one of its most important events, the ENANCIB, in the years that range from 2003 to 2009, having as our theoretical foundation Jürgen Haberman’s knowledge theory. This work can be considered as a documental research in which a qualitative approach of interpretative nature prevails. Among other findings, it was possible to determine that nearly 91% of all papers present a technical interest, while practical interests represent nearly 8% and emancipatorial interests represent only 1% of all papers. It was also possible to verify a strong tendency to use technical methods, underestimating the practical and emancipatorial interests that consider and enhance the presence of different social actors.A ciência da informação busca em outras áreas do conhecimento elementos que a auxiliem na ampliação da compreensão acerca de seu objeto de estudo, a informação. É importante analisar de que forma o processo de construção teórica vem acontecendo. Esse trabalho tem como objetivo avaliar o estado da arte da área de Ciência da Informação no Brasil, a partir da análise de trabalhos publicados nos anais do Encontro Nacional de Pesquisa em Ciência da Informação (ENANCIB), no período de 2003 a 2009, utilizando-se como base conceitual a teoria do conhecimento de Jürgen Habermas. Este estudo pode ser caracterizado como uma pesquisa documental, em que predomina o método qualitativo de natureza interpretativa. Entre alguns dos resultados, percebeu-se que o interesse técnico engloba aproximadamente 91% de todos os trabalhos publicados nos ENANCIBs, enquanto o interesse prático representa aproximadamente 8% dos trabalhos e o interesse emancipatório constitui apenas 1%. Foi possível ainda verificar na análise dos resultados do estudo uma tendência generalizada ao interesse técnico, que de certa forma reproduz os métodos vigentes nesse campo científico em detrimento dos interesses práticos e emancipatórios que valorizam e potencializam a presença dos diversos atores sociais