499 research outputs found
A multiphase model of tumour segregation in situ by a heterogeneous extracellular matrix
Normal and tumour cells live in a fibrous environment that is often very heterogeneous, even characterized by the presence of basal membranes and regions with high density of collagen fibres that physiologically comparmentalize cells in well defined regions, as for in situ tumours. In case of metastatic tumours these porous structures are instead invaded by cancer cells. The aim of this paper is to propose a multiphase model that is able to describe cell segregation by thick porous structures and to relate the transition rule that determines whether cells will pass or not to microscopic characteristics of the cells, such as the stiffness of their nucleus, their adhesive and traction abilities, the relative dimension of their nucleus with respect to the dimension of the pores of the extra-cellular matrix. (C) 2015 Elsevier Ltd. All rights reserved
Evaluation and Correction of B1+-Based Brain Subject-Specific SAR Maps Using Electrical Properties Tomography
The specific absorption rate (SAR) estimates the amount of power absorbed by the tissue and is determined by the electrical conductivity and the E-field. Conductivity can be estimated using Electric Properties Tomography (EPT) but only the E-field component associated with B-1(+) can be deduced from B-1- mapping. Herein, a correction factor was calculated to compensate for the differences between the actual SAR and the one obtained with B-1(+). Numerical simulations were performed for 27 head mod-els at 128 MHz. Ground-truth local-SAR and 10g-SAR (SAR(GT)) were computed using the exact electrical conductivity and the E-field. Estimated local-SAR and 10g-SAR (SAR(EST)) were com-puted using the electrical conductivity obtained with a convection-reaction EPT and the E-field obtained from B-1(+). Correction factors (CFs) were estimated for gray matter, white matter, and cere-brospinal fluid (CSF). A comparison was performed for different levels of signal-to-noise ratios (SNR). Local-SAR/10g-SAR CF was 3.08 +/- 0/06 / 2.11 +/- 0.04 for gray matter, 1.79 +/- 0/05 / 2.06 +/- 0.04 for white matter, and 2.59 +/- 0/05 / 1.95 +/- 0.03 for CSF. SAR(EST) without CF were underestimated (ratio across [infinity -25] SNRs: 0.52 +/- 0.02 for local-SAR; 0.55 +/- 0.01 for 10g-SAR). After cor-rection, SAREST was equivalent to SAR(GT) (ratio across [infinity -25] SNRs: 0.97 +/- 0.02 for local-SAR; 1.06 +/- 0.01 for 10g-SAR). SAR maps based on B-1(+) can be corrected with a correction factor to compensate for potential differences between the actual SAR and the SAR calculated with the E-field derived from B-1(+)
Propuesta Ágil para Gestionar Proyectos Educativos Informáticos en Educación Superior
El artículo describe la gestión ágil de proyectos educativos informáticos en contextos de educación superior en la Argentina. En particular, esta experiencia se sitúa en relación con el proceso de enseñanza y aprendizaje significativo debido la importancia del desarrollo del software en todas sus dimensiones y aplicaciones. En el método se describen los elementos adaptados de SCRUM, metodología de trabajo ágil iterativa e incremental para la gestión de proyectos, y cómo se incorpora un sistema de matrices de tres categorías. El resultado de esta innovadora integración se plasma en una propuesta ágil que integra prácticas y artefactos de SCRUM con un sistema de matrices categoriales orientadas a presentar: los objetivos correlacionados, la relación de actores e instrumentos de recolección de datos y una matriz que refleja: la Apropiación de aprendizajes para el uso de una metodología ágil, el Reconocimiento de los roles de los integrantes del equipo, la Comunicación eficaz para la interacción de los miembros del equipo. La propuesta se valida considerando la presentación y exposición de los trabajos integradores en una asignatura de la carrera Licenciatura en Sistemas de Información. Finalmente, es menester abordar el proceso de enseñanzaaprendizaje significativo situado en contexto ágiles atendiendo a la complejidad y emergentes continuos en la actual sociedad del conocimiento.
The article describes an agile managing for educational IT projects in higher education. Argentina is the reference context. In particular, the experience is placed in relation to the process of teaching and learning meaning, considering the software development in all its dimensions and applications. The method describes the elements adapted from SCRUM, iterative and incremental agile working methodology for project management, and how a three-category matrix system is incorporated. The result of this innovative integration is embodied in an agile proposal that integrates SCRUM practices and artifacts with a system of categorical matrices oriented to present: the correlated objectives, the relationship of actors and data collection instruments and the last one containing the following items: the appropriation of learning for the use of an agile methodology, the recognition of the roles of the team members, the effective communication for the interaction of the team members. The proposal is validated considering the presentation and exposition of the integrative works in a subject of the Information Systems degree. Finally, it is necessary to approach the process of significant teaching-learning located in an agile context, taking into account the complexity and continuous emergences in the current knowledge society
Editorial : Deprescribing and Minimizing Use of Anticholinergic Medications
Peer reviewedPublisher PD
The Peptide A-3302-B Isolated from a Marine Bacterium Micromonospora sp. Inhibits HSV-2 Infection by Preventing the Viral Egress from Host Cells
El comercio electrónico
Que INTERNET ha impactado en las comunicaciones, las relaciones personales y sociales, la educación, la cultura, el tráfico de información y de bienes y servicios, es un dato que nos proporciona la realidad.Frente a ello el comercio, y más precisamente, las empresas, no han permanecido ajenas a este proceso, rotulándose -en lo jurídico- bajo la denominación “comercio electrónico”, una serie de situaciones, problemas e interrogantes que se derivan de esta nueva realidad que exhibe, como característica sobresaliente, la multiplicidad de conocimientos que involucra y que requiere, para su abordaje integral, de un tratamiento interdisciplinario.Como resaltan BRIZZIO y ORTEGA con la generalización del denominado “comercio electrónico”, son varios los aspectos jurídicos que se encuentran directa o tangencialmente afectados o alcanzados: la publicidad registral, las marcas y patentes, la oferta, la aceptación, la ejecución y la extinción de contratos comerciales, los derechos de los consumidores, el derecho aduanero, el transporte, -marítimo, aéreo, terrestre e inclusive espacial-, los delitos informáticos ya tan usuales, su influencia en el derecho tributario, la responsabilidad emergente en este nuevo campo del conocimiento, etc
Evidence of semantic processing in parafoveal reading: a rapid parallel visual presentation (Rpvp) study
This study explores whether semantic processing in parafoveal reading in the Italian language is modulated by the perceptual and lexical features of stimuli by analyzing the results of the rapid parallel visual presentation (RPVP) paradigm experiment, which simultaneously presented two words, with one in the fovea and one in the parafovea. The words were randomly sampled from a set of semantically related and semantically unrelated pairs. The accuracy and reaction times in reading the words were measured as a function of the stimulus length and written word frequency. Fewer errors were observed in reading parafoveal words when they were semantically related to the foveal ones, and a larger semantic facilitatory effect was observed when the foveal word was highly frequent and the parafoveal word was short. Analysis of the reaction times suggests that the semantic relation between the two words sped up the naming of the foveal word when both words were short and highly frequent. Altogether, these results add further evidence in favor of the semantic processing of words in the parafovea during reading, modulated by the orthographic and lexical features of the stimuli. The results are discussed within the context of the most prominent models of word processing and eye movement controls in reading
Técnicas de control de concurrencia en base de datos: implementación en un sistema de gestión
Las transacciones concurrentes en una aplicación que se implementa en una estructura cliente servidor, es de vital importancia, dado que mantener la coherencia, integridad y durabilidad de los datos que son consumidos no es una tarea trivial. La elección de una técnica de manejo de concurrencia que permita la serialización de las transacciones y la coherencia de las operaciones realizadas sobre dichos datos, debe ejecutarse de acuerdo a la naturaleza del problema que se esté tratando de resolver. En el presente artículo, se presenta la aplicación técnicas de concurrencia optimista, al modulo “autogestión de compras” en un Sistema de Gestión de Ventas. Los resultados demuestran que con la aplicación de la técnica mencionada y de acuerdo a operaciones que no suponen un bloqueo, o que el bloqueo resultaría costoso en el rendimiento del sistema, es decir, en tiempo y recursos, se consigue mantener la integridad y coherencia de los datos.X Workshop Innovación en Sistemas de Software (WISS)Red de Universidades con Carreras en Informática (RedUNCI
Evaluation of subcutaneous proleukin (Interleukin-2) in a randomized international trial (ESPRIT): Geographical and gender differences in the baseline characteristics of participants
Background: ESPRIT, is a phase III, open-label, randomized, international clinical trial evaluating the effects of subcutaneous recombinant interleukin-2 (rIL-2) plus antiretroviral therapy (ART) versus ART alone on HIV-disease progression and death in HIV-1-infected individuals with CD4+ T-cells ≥300 cells/μL. Objectives: To describe the baseline characteristics of participants randomized to ESPRIT overall and by geographic location. Method: Baseline characteristics of randomized participants were summarized by region. Results: 4,150 patients were enrolled in ESPRIT from 254 sites in 25 countries. 41%, 27%, 16%, 11%, and 5% were enrolled in Europe, North America, South America, Asia, and Australia, respectively. The median age was 40 years, 81% were men, and 76%, 11%, and 9% were Caucasian, Asian, and African American or African, respectively. 44% of women enrolled (n = 769) were enrolled in Thailand and Argentina. Overall, 55% and 38% of the cohort acquired HIV through male homosexual and heterosexual contact, respectively. 25% had a prior history of AIDS-defining illness; Pneumocystis jirovecii pneumonia, M. tuberculosis, and esophageal candida were most commonly reported. Median nadir and baseline CD4+ T-cell counts were 199 and 458 cells/μL, respectively. 6% and 13% were hepatitis B or C virus coinfected, respectively. Median duration of antiretroviral therapy (ART) was 4.2 years; the longest median duration was in Australia (5.2 years) and the shortest was in Asia (2.3 years). 17%, 13%, and 69% of participants began ART before 1995, between 1996 and 1997, and from 1998 onward, respectively. 86% used ART from two or more ART classes, with 49% using a protease inhibitor-based regimen and 46% using a nonnucleoside reverse transcriptase inhibitor-based regimen. 78% had plasma HIV RNA below detection (<500 cp/mL). Conclusion: ESPRIT has enrolled a diverse population of HIV-infected individuals including large populations of women and patients of African-American/African and Asian ethnicity often underrepresented in HIV research. As a consequence, the results of the study may have wide global applicability
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