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Role of Guanidyl Moiety in the Insertion of Arginine and Nα-Benzoyl-l-argininate Ethyl Ester Chloride in Lipid Membranes

Fonseca, A. C.; Frías, M. A.; Bouchet, A. M.; Jarmelo, S.; Simões, P. N.; Fausto, R.; Gil, M. H.; Lairion, F.; Disalvo, E. A.
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artigo de Revista Científica
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Role of Guanidyl Moiety in the Insertion of Arginine and Nα-Benzoyl-l-argininate Ethyl Ester Chloride in Lipid Membranes AbstractFull Text HTMLHi-Res PDF[1247 KB]PDF w/ Links[216 KB]FiguresReferencesA. C. Fonseca‡, M. A. Frías†, A. M. Bouchet†, S. Jarmelo‡§, P. N. Simões‡, R. Fausto§, M. H. Gil‡, F. Lairion† and E. A. Disalvo*† Laboratory of Physical Chemistry of Lipid Membranes, Department of Analytical Chemistry and Physical Chemistry, Pharmacy and Biochemistry, University of Buenos Aires Junín 956 2° piso (1113), Buenos Aires, Argentina, Department of Chemical Engineering, University of Coimbra, Polo II, Pinhal de Marrocos, 3030-790 Coimbra, Portugal, and Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal J. Phys. Chem. B, 2010, 114 (17), pp 5946–5952 DOI: 10.1021/jp101007b Publication Date (Web): April 13, 2010 Copyright © 2010 American Chemical Society * Corresponding author. Phone: 54 11 39648249. Fax: 54 11 45083645. E-mail: eadisal@yahoo.com.ar., † Department of Analytical Chemistry and Physical Chemistry, Pharmacy and Biochemistry, University of Buenos Aires Junín 956 2° piso (1113). , ‡ Department of Chemical Engineering, University of Coimbra. , § Department of Chemistry...

O novo papel do designer instrucional e designer gráfico na era dos tablets educativos

Tessaro, Annye Cristiny; Bunn, Denise Aparecida; Costa, Alexandre Marino; Costa, Patricia Regina; Moritz, Gilberto Oliveira
Fonte: Universidade Aberta; LE@D Publicador: Universidade Aberta; LE@D
Tipo: Conferência ou Objeto de Conferência
Publicado em /12/2013 Português
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A utilização dos tablets como instrumento pedagógico é uma realidade que está aos poucos surgindo no contexto escolar. Os dispositivos móveis já fazem parte da rotina dos estudantes. Na era digital, estar conectado é fazer parte do mundo, é ter uma posição privilegiada da informação e da comunicação. Considerar esses dispositivos como instrumentos pedagógicos emerge da necessidade de se agregar a realidade dos estudantes ao contexto educacional. A inserção dos tablets já está ocorrendo, ainda que de forma incipiente e em um contex to amplo, sem muitas pesquisas que comprovem sua eficácia. Sendo assim, a função do designer instrucional fica ainda mais emocionante e desafiadora: esse profissional precisa oferecer muito mais do que um simples “clic” para que o estudante se envolva no texto. O texto precisa ser interativo, precisa ter mobilidade. Já não se pode mais afirmar que um livro disponibilizado em arquivo.pdf é uma modernidade, pois eles agora estão passando por um processo de virtualização, os chamados e-books (livros virtuais). Recursos, aplicativos e até mesmo livros digitais precisam ser discutidos e avaliados sob uma ótica planejada, bem fundamentada em teorias de aprendizagem...

Analysis of two reinforced concrete pile caps with embedded sockets in the presence of a locking beam

BARROS, Rodrigo
Fonte: ESCOLA DE MINAS Publicador: ESCOLA DE MINAS
Tipo: Artigo de Revista Científica
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The present research studies the behavior of reinforced concrete locking beams supported by two capped piles with the socket embedded; used as connections for pre-cast concrete structures. The effect provoked by locking the beam on the pile-caps when supported by the lateral socket walls was evaluated. Three-dimensional numerical analyses using software based on the finite element method (FEM) were developed considering the nonlinear physical behavior of the material. To evaluate the adopted software, a comparative analysis was made using the numerical and experimented results obtained from other software. In the pile caps studied, a variation in the wall thickness, socket interface, strut angle inclination and action on beam. The results show that the presence of a beam does not significantly change pile cap behavior and that the socket wall is able to effectively transfer the force from the beam to the pile caps. By the tensions on the bars of longitudinal reinforcement, it was possible to obtain the force on the tie and the strut angle inclination before the collapse of models. It was found that the angles present more inclinations than those used in the design, which was made based on a strut-and-tie model. More results are available at http://www.set.eesc.usp.br/pdf/download/2009ME_RodrigoBarros.pdf

Universality in bibliometrics

Silva, Roberto da; Kalil, Fahad; Moreira de Oliveira, Jose Palazzo; Martinez, Alexandre Souto
Fonte: ELSEVIER SCIENCE BV; AMSTERDAM Publicador: ELSEVIER SCIENCE BV; AMSTERDAM
Tipo: Artigo de Revista Científica
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Many discussions have enlarged the literature in Bibliometrics since the Hirsch proposal, the so called h-index. Ranking papers according to their citations, this index quantifies a researcher only by its greatest possible number of papers that are cited at least h times. A closed formula for h-index distribution that can be applied for distinct databases is not yet known. In fact, to obtain such distribution, the knowledge of citation distribution of the authors and its specificities are required. Instead of dealing with researchers randomly chosen, here we address different groups based on distinct databases. The first group is composed of physicists and biologists, with data extracted from Institute of Scientific Information (IS!). The second group is composed of computer scientists, in which data were extracted from Google-Scholar system. In this paper, we obtain a general formula for the h-index probability density function (pdf) for groups of authors by using generalized exponentials in the context of escort probability. Our analysis includes the use of several statistical methods to estimate the necessary parameters. Also an exhaustive comparison among the possible candidate distributions are used to describe the way the citations are distributed among authors. The h-index pdf should be used to classify groups of researchers from a quantitative point of view...

USO DO DUBLIN CORE NA DESCRIÇÃO DE OBRAS RARAS NA WEB: A COLEÇÃO DA BIBLIOTECA BRASILIANA DIGITAL

Pires, Daniela
Fonte: Fundação Biblioteca Nacional; Rio de Janeiro Publicador: Fundação Biblioteca Nacional; Rio de Janeiro
Tipo: Conferência ou Objeto de Conferência
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Acessível ao público desde junho de 2009, a Biblioteca Brasiliana Digital, da Universidade de São Paulo tem por objetivo facultar para a pesquisa, a maior Brasiliana custodiada por uma universidade. Sua intenção é disponibilizar virtualmente parte do acervo da Universidade oferecendo-se como um instrumento útil e funcional para a pesquisa e o estudo dos temas e cultura brasileiros, além de oferecer um modelo tecnológico de gestão que possa ser difundido a outras coleções, acervos e instituições. Este trabalho apresenta os resultado da implantação de um esquema de metadados baseado no formato Dublin Core, para a descrição de obras raras e especiais na web. Especificamente, apresenta os procedimentos e processos de descrição de conteúdos das diversas tipologias documentais (livros, periódicos, gravuras etc.) e formatos digitais (pdf, jpeg entre outros). Palavras-Chave: Bibliotecas digitais; Metadados; Dublin Core.; Available for the public access since June 2009, the University of Sao Paulo Brasiliana Digital Library, aims to provide to the research the largest Brasiliana guarded by an University. The purpose is make available online part of the University Collection, as an useful and functional instrument to the research and study of Brazilian themes and culture...

Contribuição à investigação das alterações hemostáticas induzidas pelo veneno da serpente Bothrops jararaca em coelhos: estudo das glicoproteínas da membrana, função, secreção e sobrevivência plaquetárias. ; Contribution to the investigation of hemostatic disturbances induced by Bothrops jararaca snake venom in rabbits: study of platelet membrane glycoproteins, function, secretion and survival.

Santoro, Marcelo Larami
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 15/05/2002 Português
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Que o envenenamento pela serpente Bothrops jararaca causa distúrbios hemorrágicos sistêmicos, com alteração da coagulação e fibrinólise sangüíneas, é notório. Contudo, pouco se sabe sobre a ação in vivo desse veneno sobre as plaquetas. Em estudos recentes, demonstrou-se que esse veneno causa trombocitopenia, distúrbios da agregação e diminuição do número de corpos densos plaquetários, que, dessarte, sugeriam a ativação das plaquetas circulantes. Com o escopo de comprovar esta hipótese e melhor caracterizar as ações in vivo desse veneno sobre as plaquetas, serviu-se de um modelo experimental que empregava coelhos para o envenenamento pela B. jararaca. No grupo experimental, os animais foram injetados i.v. com o veneno da B. jararaca (60 µg/kg) e no grupo controle com salina. Previamente à administração de salina ou veneno, os coelhos tiveram suas plaquetas marcadas ex vivo com NHS-biotina. Para a avaliação das alterações plaquetárias, amostras de sangue foram coletadas seqüencialmente, em intervalos de tempo que variaram de 1 a 144 horas após a administração do veneno ou salina. Durante o envenenamento, houve trombocitopenia, hipofibrinogenemia, elevação dos níveis plasmáticos do fator de von Willebrand...

Abordagem simbólica de aprendizado de máquina na recuperação automática de artigos científicos a partir de web; Symbolic approach of machine learning in the scientific article automatic recovery from the web

Brasil, Christiane Regina Soares
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 07/04/2006 Português
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Atualmente, devido ao incessante aumento dos documentos científicos disponíveis na rede mundial de computadores, as ferrametas de busca tornaram-se um importante auxílio para recuperação de informação a partir da Internet em todas as áreas de conhecimento para pesquisadores e usuários. Entretanto, as atuais ferramentas de busca disponíveis selecionam uma enorme lista de páginas, cabendo ao usuário a tarefa final de escolher aquelas que realmente são relevantes a sua pesquisa. Assim, é importante o desenvolvimento de técnicas e ferramentas que não apenas retornem uma lista de possíveis documentos relacionados com a consulta apresentada pelo usuário, mas que organizem essa informação de acordo com o conteúdo de tais documentos, e apresentem o resultado da busca em uma representação gráfica que auxilie a exploração e o entendimento geral dos documentos recuperados. Neste contexto, foi proposto o projeto de uma Ferramenta Inteligente de Apoio à Pesquisa (FIP), do qual este trabalho é parte. O objetivo deste trabalho é analisar estratégias de recuperação automática de artigos científicos sobre uma determinada área de pesquisa a partir da Web, que poderá ser adotada pelo módulo de recuperação da FIP. Neste trabalho são considerados artigos escritos em inglês...

Nonradial oscillations of the Be star Gamma Cassiopeiae

Yang, Stephenson; Ninkov, Zoran; Walker, Gordon
Fonte: Astronomical Society of the Pacific Publicador: Astronomical Society of the Pacific
Tipo: Artigo de Revista Científica Formato: 1398522 bytes; application/pdf
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Subfeatures < 0.5% of continuum were detected moving through the line profiles of the Be/shell star y Cas over a nine-month period in 1983. While the average spacing and acceleration of the subfeatures is consistent with nonradial pulsation of |m| = 12 +/- 4, large variations in the acceleration of the subfeatures are sometimes seen and some subfeatures appear and disappear suddenly. The subfeatures appeared particularly chaotic on 1983 October 26, five days prior to detection of a strong X-ray flare with the Tenma satellite. The observed period of the subfeature oscillations varies between 7000 and 10,000 seconds which is similar to the transient 6000-second variation in X-ray flux found by EXOSAT in December 1984. No rapid E/C variation is observed in the Hy and He I _5876 emission-line profiles (Refer to PDF file for exact formulas).; This article may also be accessed on the publisher's website at: http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1988PASP..100..233Y&data_type=PDF_HIGH&type=PRINTER&filetype=.pdf; We thank Drs. G.G. Fahlman and M.A. Smith for helpful comments and suggestions. This research was supported by funds granted to one of us (G.A.H.W.) from the Natural Sciences and Engineering Research Council of Canada.

The Primary orbit and the absorption-lines of HDE-226868 (Cygnus X-1)

Ninkov, Zoran; Walker, Gordon; Yang, Stephenson
Fonte: The University of Chicago Press Publicador: The University of Chicago Press
Tipo: Artigo de Revista Científica Formato: 1633832 bytes; application/pdf
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From Reticon spectra of ~1 A resolution taken between 1980 and 1984, the radial velocity curve of HDE 226868 is found to be characteristic of a single-line spectroscopic binary with K = 75.0 +/- 1.0 km s^-1 and e=0.0. Combining historical velocities from the literature with our own data and applying a period-folding analysis, a period of 5.59964 +/- 0.00001 days is found. These values agree well with those published by Gies and Bolton in 1982, v sin i is estimated tob e 94.3 +/- 5 km s^-1 from CFHT Reticon spectra taken at 0.1 A resolution. Assuming that the rotation of the primary is synchronized to the orbital revolution of the secondary gives a primary to secondary mass between 1.5 and 2.3. An absolute magnitude of -6.5 +/- 0.2 is derived from the equivalent width of Hy (1.5 +/- 0.1 A) and the 1985 calibration of Walker and Millward which is consistent with the spectral classification of 09.7 Iab. Assuming 20 M_ as a reasonable estimate for the mass of the primary implies a mass of 10 +/- 1 M_ for the secondary. The equivalent width of Hy and HB are 20% larger at zero phase (X-ray minimum) of the 294 day X-ray period. A variation in the outflow rate from the primary could produce variations in both the Balmer-line equivalent widths and the X-ray flux (Refer to PDF file for exact formulas).; This article may also be accessed on the publisher's website at: http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1987ApJ...321..425N&data_type=PDF_HIGH&type=PRINTER&filetype=.pdf; Z. Ninkov acknowledges the support of a Canadian Commonwealth Scholarship and Fellowship Plan Award and the facilities at the Department of Physics and Astronomy...

Mean stress effects on random fatigue of nonlinear structures

Sweitzer, Karl; Ferguson, N.S.
Fonte: Twelfth International Congress on Sound and Vibration Publicador: Twelfth International Congress on Sound and Vibration
Tipo: Proceedings
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Random fatigue analysis techniques have concentrated on linear structures that exhibit symmetric stress range probability density functions (PDF). In narrowband response and broadband random response it is assumed that the bending stress range PDF is symmetric and has zero mean stress. Structures that can exhibit geometrical nonlinearity, under large deflections, typically introduce membrane effects, which are additional positive tensile stresses that tend to skew the stress range PDF. This paper investigates fatigue analysis approaches that include mean stress effects and show how they can be applied to nonlinear random vibration problems.; Conference proceedings from the twelfth international congress on sound and vibration.

The Ismar David archive: An Electronic finding aid

Colodny, Susan
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
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Ismar David ( 1910 1996) was a German-born graphic artist who launched his professional career in Jerusalem and moved in 19C2 to live and work in the United States. He is noted for his brilliant work in Hebrew and Latin calligraphy, lettering, and type design, as well as a distinctive linear style of illustration. Over a span of six decades, Ismar David amassed an archive of materials that chronicles his design career. In 1997, the archive was donated to the Melbert B. Cary Jr. Graphic Arts Collection at the Rochester Institute of Technology, where it will be preserved and made available for research. To facilitate the use of an archival collection for research, a repository pre pares what is called a finding aid. A finding aid traditionally provides a detailed description of the collection contents and organizes the materials in a coherent and systematic way. In addition, a finding aid often explains a collection's origin, gives relevant biographical information, and notes the scope and content of a collection. Parts of a collection are usually listed with container numbers that are used to identify and request items for examination. In recent years libraries and other archival repositories have begun to "publish" electronic finding aids on the World Wide Web to help researchers learn the exact content of a collection from a remote location and avoid the travel and detective work that was accepted as part of the research process prior to the explosive growth of the Internet. Many text-encoding options exist and are currently used to create electronic finding aids...

The Application of the conjugate-gradient method to the solution of transient electromagnetic scattering from thin wires

Rao, Sadasiva; Sarkar, Tapan; Dianat, Sohail
Fonte: American Geophysical Union (AGU) Publicador: American Geophysical Union (AGU)
Tipo: Artigo de Revista Científica Formato: 1193328 bytes; application/pdf
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Previous approaches to the problem of computing scattering by conducting bodies have utilized the well-known marching-on-in-time solution procedures. However, these procedures are very dependent on discretization techniques and sometimes lead to instabilities as the time progresses. Moreover, the accuracy of the solution cannot be verified easily, and usually there is no error estimation. In this paper we describe the conjugate gradient method for solving transient problems. For this method, the time and space discretizations are independent of one another. The method has the advantage of a direct method as the solution is obtained in a finite number of steps and also of an iterative method since the roundoff and truncation errors are limited only to the last stage of iteration. The conjugate gradient method converges for any initial guess; however, a good initial guess may significantly reduce the computation time. Also, explicit error formulas are given for the rate of convergence of this method. Hence any problem may be solved to a prespecified degree of accuracy. The procedure is stable with respect to roundoff and truncation errors and simple to apply. As an example, we apply the method of conjugate gradient to the problem of scattering from a thin conducting wire illuminated by a Gaussian pulse. The results compare well with the marching-on-in-time procedure.; An edited version of this paper was published by AGU. Copyright 1984 American Geophysical Union. Original source of PDF file: http://www.cis.syr.edu/~tksarkar/pdf/1984_Oct.pdf; This work has been supported in part by the Office of Naval Research under contract N00014-79-C-0598.

Accurate spectral estimation from unequally spaced samples of exponentially damped sinusoidal signals

Sarkar, Tapan; Chen, Huanqun; Dianat, Sohail
Fonte: Institute of Electrical and Electronics Engineers (IEEE) Publicador: Institute of Electrical and Electronics Engineers (IEEE)
Tipo: Artigo de Revista Científica Formato: 771749 bytes; application/pdf
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In this paper a method is presented to interpolate and extrapolate unequally spaced signals that are not bandlimited. This is achieved by utilizing the Gregory-Newton quadrature formula which circumvents aliasing without bandlimiting. Also with the Gregory-Newton quadrature formula, it is possible to compute the Fourier spectrum of the unequally spaced signals, which is not bandlimited. Finally, the effect of noise on the Gregory-Newton quadrature formula is observed. Specifically, the quality of interpolation, extrapolation, and the spectrum as a function of various signal-to-noise ratios is observed. This may be a useful technique for computing unaliased spectra of unequally spaced amped sinusoidal signals having a signal-to-noise ratio greater than 20 dB.; Original source of PDF file: http://www.cis.syr.edu/~tksarkar/pdf/1987_Mar_2.pdf

On the statistics of hyperspectral imaging data

Manolakis, Dimitris; Marden, David; Kerekes, John; Shaw, Gary
Fonte: International Society for Optical Engineering (SPIE) Publicador: International Society for Optical Engineering (SPIE)
Tipo: Proceedings Formato: 453001 bytes; application/pdf
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Characterization of the joint (among wavebands) probability density function (pdf) of hyperspectral imaging (HSI) data is crucial for several applications, including the design of constant false alarm rate (CFAR) detectors and statistical classifiers. HSI data are vector (or equivalently multivariate) data in a vector space with dimension equal to the number of spectral bands. As a result, the scalar statistics utilized by many detection and classification algorithms depend upon the joint pdf of the data and the vector-to-scalar mapping defining the specific algorithm. For reasons of analytical tractability, the multivariate Gaussian assumption has dominated the development and evaluation of algorithms for detection and classification in HSI data, although it is widely recognized that it does not always provide an accurate model for the data. The purpose ofthis paper is to provide a detailed investigation ofthejoint and marginal distributional properties of HSI data. To this end, we assess how well the multivariate Gaussian pdf describes HSI data using univariate techniques for evaluating marginal normality, and techniques that use unidimensional views (projections) of multivariate data. We show that the class of elliptically contoured distributions...

Text Mining in Full Text Articles -- Methodical and Represenation Issues

Roman Klinger; Robert Pesch; Theo Mevissen; Juliane Fluck
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Poster
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In many cases, information from abstracts of biomedical publications is not sufficient for annotation of database entries. Therefore, text mining systems supporting curators of biodatabases should be able to process full text articles. Beside the technical problems arising from full text parsing, the representation of the annotated full text is an important issue. Journal articles are mostly electronically available in PDF or HTML format. Also with more easily manageable XML formats, readers would like to have a visualisation of annotations and semantic enrichment directly in the PDF or HTML. We summarize the technical problems arising from parsing of HTML and PDF journal full texts and show first results of visualisation in both formats.

Local structural distortion and electrical transport properties of Bi(Ni1/2Ti1/2)O3 perovskite under high pressure

Zhu, Jinlong; Yang, Liuxiang; Wang, Hsiu-Wen; Zhang, Jianzhong; Yang, Wenge; Hong, Xinguo; Jin, Changqing; Zhao, Yusheng
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Text
Publicado em 16/12/2015 Português
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Perovskite-structure materials generally exhibit local structural distortions that are distinct from long-range, average crystal structure. The characterization of such distortion is critical to understanding the structural and physical properties of materials. In this work, we combined Pair Distribution Function (PDF) technique with Raman spectroscopy and electrical resistivity measurement to study Bi(Ni1/2Ti1/2)O3 perovskite under high pressure. PDF analysis reveals strong local structural distortion at ambient conditions. As pressure increases, the local structure distortions are substantially suppressed and eventually vanish around 4 GPa, leading to concurrent changes in the electronic band structure and anomalies in the electrical resistivity. Consistent with PDF analysis, Raman spectroscopy data suggest that the local structure changes to a higher ordered state at pressures above 4 GPa.

Maquinismos Emocionais das Narrativas Jornalísticas Turísticas

Baptista, Maria Luiza Cardinale
Fonte: Revista Observatório Publicador: Revista Observatório
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; Formato: application/pdf
Publicado em 27/12/2015 Português
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O presente artigo discute aspectos psicomunicacionais, presentes nas narrativas jornalísticas turísticas contemporâneas, consolidados e expressos em feixes emocionais que se perfilam e demonstram as inflexões midiáticas contemporâneas. Trata-se de um conjunto de reflexões teóricas, a partir da observação das narrativas contemporâneas, ligadas ao Turismo, e do aprofundamento dos estudos do que a autora chama de Psicomunicação, com base em substratos teóricos transdisciplinares. O texto traz o contraponto entre o texto clássico do Jornalismo, marcado por uma espécie de esterilização emocional, com a consolidação de esquemas narrativos aparentemente objetivantes, e a composição atenta e intencional de feixes emocionais, como valores emocionais agregados, subjacentes às produções veiculadas nos vários espaços jornalísticos, inclusive os voltados ao Turismo. Palavras-chave: jornalismo; turismo, psicomunicação; narrativa; emoção.     Emotional Mechanisms of Tourist Journalistic Narratives   AbstractThis article discusses psicommunication aspects, in the contemporary tourist journalistic narratives, consolidated and expressed in emotional beams that lie and demonstrate the contemporary media inflections. It is a set of theoretical reflections...

Reliability in urban freight distribution: A Markovian approach

Cedillo-Campos,Miguel Gastón; Riva-Canizales,José Luis de la; Bueno-Solano,Alfredo; Gonzalez-Feliu,Jesús; García-Alcaraz,Jorge Luis
Fonte: DYNA Publicador: DYNA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2014 Português
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A key element in assessing reliability in urban freight distribution (UFD) is the probability density function (PDF) of the variables that characterize the performance of the distribution routes. This article presents a method for modeling the PDF with an approach based on the Markov models, under the assumption that the present status of reliability of a route depends only on its immediate previous state. Currently, the PDF is obtained directly from the field, therefore an analytical model that provides certainty to the analysis is essential. The results are applicable both to the design of routes and operation of the same process. The originality of this work is based on the development of a methodological procedure to assess the reliability of the components of a path, complementary to current methodologies to calculate network reliability.

Analysis of Multipath Propagation based on Cluster Channel Modelling Approach

Arias,Marvin R.
Fonte: Instituto Politécnico Nacional, Centro de Innovación y Desarrollo Tecnológico en Cómputo Publicador: Instituto Politécnico Nacional, Centro de Innovación y Desarrollo Tecnológico en Cómputo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2010 Português
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The computer simulation approach with an emphasis on the propagation modelling for wireless channels for current and future communication systems is a powerful tool to asses the performance of systems without the need of building them. This paper presents a clustering approach geometry-based channel model, and employs it to derive the power density function (PDF) of the Angle of Arrival (AOA) of the multipath signal components. To evaluate the theoretical clusters PDF in angular domain proposed, we make computer simulations for the geometry-based channel model proposed and compared it with experimental results published in the literature showing good agreement. The clusters PDF derived can be used to simulate the power-delay-angle profile (PDAP) and to quantify second order statistics, i.e., power angular spectrums (PAS) and the associated angular spreads (Ass) for a given elliptical shape of the cluster.

Khumani Iron Ore Mine paste disposal and water recovery system

du Toit,T; Crozier,M
Fonte: Journal of the Southern African Institute of Mining and Metallurgy Publicador: Journal of the Southern African Institute of Mining and Metallurgy
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2012 Português
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Traditional iron ore beneficiation plants using washing, screening, and jigging processes require large volumes of process water. However, when a suitable large iron ore deposit is found in a location where rainfall is erratic and raw water sources are limited, innovative process designs are required to minimize water losses, maximize re-use of process water, and minimize raw water intake to ensure the project viability. This case study provides an overview of the Khumani paste disposal facility (PDF) located in the Northern Cape Province of South Africa. The plant uses a central ring main water reticulation circuit combined with a two-stage thickening system to maximize water recovery. At the process plant there are two large 90 m diameter traction thickeners and at the PDF two 18 m paste thickeners. The net raw water usage has been minimized, and water losses on the PDF are at levels of between 0.43 to 0.69 m³/t deposited.S