Uma comparação entre Antispams do tipo desafio-resposta e estatísticos: uma experiência da Embrapa Informática Agropecuária.

bitstream/CNPTIA/11085/1/comtec68.pdfAcesso em: 28 maio 2008

A New Integrated Approach for Fast Intrinsic Dielectric Breakdown

FCT-MCTES Portugal through UID/EEA/00066/2013 is gratefully acknowledged.A non-equilibrium phenomenological description for a complete dielectric breakdown sequence in perfect solid electric insulators, from the dynamics of instability to the growth of branching patterns, is implemented. It represents an original treatment which allows overcoming the current lack of such a complete physical description, involving thermodynamics, and in particular equations on maximum dissipation energy for dielectric breakdown are developed. From the assumption that there is a time delay in the energy rates and propagation speeds between the system input and output, a principle of maximum energy dissipation is postulated and corresponding dynamic evolution equations were obtained. It is shown that the delay in those speeds gives rise to the appearance of iterated equations which in turn leads to the logistic maps describing the dynamic evolution of the system. The results can describe the instability process along with dissipation patterns formation. The vast theoretical and experimental analogies between mechanical fracture and dielectric rupture, lead us to foresee the potential applicability of this model in the prediction of dielectric rupture patterns. This work opens then the possibility to predict the consequent branching patterns by using a maximum energy dissipation principle, contributing in a significant way for energy efficiency engineering.publishersversionpublishe

Epistemología, caos y enseñanza de las ciencias

In this article it is maintained that modern science is going through a critical period where its epistemological assumptions and the use of a parcelling and reductionist methodology are questioned. This will surely have important implications in the teaching of the sciences, perhaps because the world today demands above all an epistemological change in the people who, within a few years, will occuppy the posts in the production and reproduction of scientific and technical knowledge

Design e roteiro de vídeos educativos.

Propõe-se a elaboração de design e roteiro de conteúdo de vídeos educativos sob o enfoque da aprendizagem significativa, que se baseia no modelo construtivista do processo cognitivo humano. Mapas conceituais são adotados como uma opção para a organização e representação do conhecimento em construção pelo aluno, sob a mediação do professor

Sistema de informação para rastreamento de pescado.

A rastreabilidade de peixes confere segurança para quem compra ou comercializa o pescado. Para que seja possível esta rastreabilidade ser usada pela sociedade, é necessário que exista algum repositório de dados que contenha, por exemplo, todo o histórico do pescado, tais como espécie, procedência, manejo, análise físico-química, biológica e microbiológica da água, características diversas relacionadas à carne e couro, e vários outros dados. Com isto, podem ser conhecidas várias características, incluindo a rastreabilidade, para se decidir sobre compra e venda de pescados de qualidade. Para atender a esta demanda, foi desenvolvido um sistema de informações de rastreabilidade relativas a diversos tipos de peixes; desta forma, o objetivo deste trabalho é demonstrar este sistema, que poderá ser usado livremente por qualquer usuário.ReCIP 2011

Biocatalytic Synthesis of Polyglycerol Polyricinoleate: A Comparison of Different Commercial Lipases

This paper describes the studies carried out to select the most suitable lipase as catalyst for the esterification of polyglycerol with polyricinoleic acid to yield polyglicerol polyricinoleate (PGPR), a value-added, bio-based food emulsifier. The enzymes assayed were lipases from Rhizopus arrhizus, Rhizopus oryzae and Mucor javanicus, previously selected because of their suitable activity and moderate cost. First, the reaction was catalyzed by free lipases in a batch reactor and the influence of different operating conditions (initial water content, amount of enzyme and temperature) on the progress of the reaction was studied. Next, the three lipases were immobilized by physical adsorption on the anion exchange resin, Lewatit MonoPlus MP 64, providing derivatives with a high activity and stability. Recovery of the immobilized derivative from the reaction medium was conducted with very good yields (≥ 99 %) and no loss of activity of the derivative with successive uses was proved. Finally, a high performance reactor, operating at low pressure and a dry atmosphere, was used to synthesise PGPR using the immobilized enzymes. Both Rhizopus arrhizus and Rhizopus oryzae lipases allowed the production of a PGPR which fulfils the “specific purity criteria on food additives other than colours and sweeteners” established by the Commission of the European Communities (AV ≤ 6 mg KOH/g), with an acid value of 4.91 and 5.31 mg KOH/g respectively

State of the art of financial research in Mexico

El objetivo de esta investigación consiste en presentar el estado que guarda la investigación en el área financiera, a partir de los trabajos académicos presentados en los tres principales foros que agrupan a una gran parte del sector académico en Ciencias Administrativas en México: Academia de Ciencias Administrativas, Foro de Investigación UNAM-FCA y Congreso de Análisis Organizacional UAM, por un período de 5 años 2003 a 2007. Los hallazgos permiten determinar que ha sido incipiente el alcance de la investigación financiera que se ha desarrollado en México en comparación con los países de Europa y Estados Unidos, el desafío para los investigadores en México es el desarrollo de temáticas como: Finanzas personales, Finanzas del comportamiento e innovación financiera, ya que han sido temas poco estudiados y contextualizados en nuestro medio.The objective of this research is to present the state of research in the financial area, from the scholarly papers presented at the three main forums which bring together much of the academic sector in Mexico Administrative Sciences: Academy of Administrative Sciences , Research Forum FCA-UNAM and UAM Congress Organizational Analysis, for a period of 5 years 2003 to 2007. The findings help determine which was the extent of incipient financial investigation that has developed in Mexico in comparison with the countries of Europe and the United States, the challenge for researchers in Mexico is the development of themes such as: Personal Finance, Finance behavior and financial innovation, as they have been little studied and contextualized issues in our environment

Proteomics analysis of gastric cancer patients with diabetes mellitus

Proteomics is a powerful approach to study the molecular mechanisms of cancer. In this study, we aim to characterize the proteomic profile of gastric cancer (GC) in patients with diabetes mellitus (DM) type 2. Forty GC tissue samples including 19 cases from diabetic patients and 21 cases from individuals without diabetes (control group) were selected for the proteomics analysis. Gastric tissues were processed following the single-pot, solid-phase-enhanced sample preparation approach—SP3 and enzymatic digestion with trypsin. The resulting peptides were analyzed by LC-MS Liquid Chromatography—Mass Spectrometry (LC-MS). The comparison of protein expression levels between GC samples from diabetic and non-diabetic patients was performed by label-free quantification (LFQ). A total of 6599 protein groups were identified in the 40 samples. Thirty-seven proteins were differentially expressed among the two groups, with 16 upregulated and 21 downregulated in the diabetic cohort. Statistical overrepresentation tests were considered for different annotation sets including the Gene Ontology(GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Reactome, and Disease functional databases. Upregulated proteins in the GC samples from diabetic patients were particularly enriched in respiratory electron transport and alcohol metabolic biological processes, while downregulated proteins were associated with epithelial cancers, intestinal diseases, and cell–cell junction cellular components. Taken together, these results support the data already obtained by previous studies that associate diabetes with metabolic disorders and diabetes-associated diseases, such as Alzheimer’s and Parkinson’s, and also provide valuable insights into seven GC-associated protein targets, claudin-3, polymeric immunoglobulin receptor protein, cadherin-17, villin-1, transglutaminase-2, desmoglein-2, and mucin-13, which warrant further investigation.This article is a result of the project DOCnet (NORTE-01-0145-FEDER-000003), supported by the Norte Portugal Regional Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF), and also by FEDER—Fundo Europeu de Desenvolvimento Regional—funds through the COMPETE 2020—Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, as well as by Portuguese funds through FCT—Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Inovação—in the framework of the project “Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274). This work was also financed by the Portuguese Mass Spectrometry Network, integrated in the National Roadmap of Research Infrastructures of Strategic Relevance (ROTEIRO/0028/2013; LISBOA-01-0145-FEDER-022125)

Counterterms and dual holographic anomalies in CS gravity

The holographic Weyl anomaly associated to Chern-Simons gravity in 2n+1 dimensions is proportional to the Euler term in 2n dimensions, with no contributions from the Weyl tensor. We compute the holographic energy-momentum tensor associated to Chern-Simons gravity directly from the action, in an arbitrary odd-dimensional spacetime. We show, in particular, that the counterterms rendering the action finite contain only terms of the Lovelock type.Comment: 10 pages, no figure