1,720,961 research outputs found
A Closed-Loop Approach to Antiretroviral Therapies for HIV Infection
No full textAntiretroviral therapies allowing for regular medical intervention in an optimal feedback role are substantiated. Individual therapies are evaluated from a multi-objective cost perspective, under different time and history constrains. The dynamics of the control system is governed by three state variables: healthy T-cells, infected T-cells, and viral particles. The drug dose administrated to the patient is taken as the manipulated or control variable. Illustrations of the methodology employed are provided for a fixed time-horizon of 180 days and variable prescription intervals, inverse discount factors, state discretization, and thresholds. Two cases are discussed: (i) beginning of the infection and (ii) near endemic equilibrium. Both open-loop and closed-loop results are presented. Dynamic Programming has been employed in the numerical treatment of the problem. Safety recommendations are also designed to cope with the chaotic behavior of the free dynamics’ flow in critical regions of the states’ domain. A software package is envisioned to assist physicians in assessing the patient ‘‘state’’, estimating antiretroviral dose prescriptions for the whole treatment period, simulating the patient’s evolution, eventually correcting the original sequence in presence of incoming data, and evaluating combined costs of alternative treatment strategies.Fil: Costanza, Vicente. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina. Universidad Nacional de San Martin. Escuela de Ciencia y Tecnología. Centro de Matemática Aplicada; ArgentinaFil: Rivadeneira Paz, Pablo Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Biafore, Federico Leonardo. Universidad Nacional de San Martin. Escuela de Ciencia y Tecnología. Centro de Matemática Aplicada; Argentina. Universidad Favaloro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: D'attellis, Carlos Enrique. Universidad Nacional de San Martin. Escuela de Ciencia y Tecnología. Centro de Matemática Aplicada; Argentina. Universidad Favaloro; Argentin
Optimizing thymic recovery in HIV patients through multidrug therapies
No full textA control-theoretic approach to the problem of designing `low-side-effects´ therapies for HIV patients based on highly active drugs is substantiated here. The evolution of side-effects during treatment is modelled by an extra differential equation coupled to the dynamics of virions, healthy T-cells, and infected ones. The new equation reflects the dependence of collateral damages on the amount of each dose administered to the patient, and on the evolution of the viral load detected by periodical blood analyses. The cost objective accounts for recommended bounds on healthy cells and virions, and also penalizes the appearance of collateral malignancies caused by the medication. The problem is solved by a hybrid Dynamic Programming scheme that adhere to discrete-time observation and control actions, but maintaining the continuous-time setup for predicting states and side-effects. The resulting optimal strategies employ less drugs than those prescribed by previous optimization studies, but maintaining high doses at the beginning and the end of each period of six months. If an inverse discount rate is applied to favor early actions, and under a mild penalization of the final viral load, then the optimal doses are found to be high at the beginning and decrease afterwards, causing a desirable stabilization of the main variables.Fil: Costanza, Vicente. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); ArgentinaFil: Rivadeneira Paz, Pablo Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); ArgentinaFil: Biafore, Federico Leonardo. Universidad Favaloro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: D'attellis, Carlos Enrique. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Universidad Favaloro; Argentin
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Cuantificación y análisis de la distribución espacial del radiotrazador 18F-DOPA en sujetos con enfermedad de Parkinson mediante el uso de imágenes cerebrales multimodales.
No full textTesis de LicenciaturaEn el presente trabajo de tesis se evaluaron diferentes indicadores cuantitativos así como la distribución espacial del radiotrazador 18F-DOPA en putámenes y caudados en individuos con Enfermedad de Parkinson (EP) y sujetos control, utilizando técnicas avanzadas de segmentación de imágenes multimodales (PET/TC y RM). El método de trabajo propuesto permite minimizar diversas fuentes de error operador-dependiente al evitar la necesidad de definir las regiones de interés de manera manual.Fil: Martino, Analía Paola. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnologí
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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