211 research outputs found

    A 2007 Model Curriculum For A Liberal Arts Degree In Computer Science

    Get PDF

    Opportunistic scheduling of flows with general size distribution in wireless time-varying channels

    Get PDF
    In this paper we study how to design an opportunistic scheduler when flow sizes have a general service time distribution with the objective of minimizing the expected holding cost. We allow the channel condition to have two states which in particular covers the important special case of ON/OFF channels. We formulate the problem as a multi-armed restless bandit problem, a particular class of Markov decision processes. Since an exact solution is out of reach, we characterize in closed-form the Whittle index, which allows us to define a heuristic scheduling rule for the problem. We then particularize the index to the important subclass of distributions with a decreasing hazard rate. We finally evaluate the performance of the proposed Whittle-index based scheduler by simulation of a wireless network. The numerical results show that the performance of the proposed scheduler is very satisfactory

    Un índice de sustentabilidad para la evaluación integral de los sistemas de gestión del agua y el saneamiento

    Get PDF
    En este trabajo se presenta un índice para la evaluación de la sustentabilidad de los sistemas de gestión del agua y el saneamiento. El índice, denominado ISAS (Índice de Sustentabilidad del Agua y el Saneamiento) se basa en un marco conceptual que considera que la sustentabilidad se debería ver como una combinación de aspectos territoriales, temporales y personales. Para la construcción del ISAS se seleccionaron un conjunto de indicadores de sustentabilidad que fueron definidos en función del marco conceptual adoptado. El ISAS se utilizó para evaluar la sustentabilidad del sistema de gestión del agua y el saneamiento de la ciudad de Salta, Argentina. Los indicadores fueron calculados con información de revisiones bibliográficas, cuestionarios, visitas, talleres, datos estadísticos, y análisis de muestras de agua y aguas residuales. El método fue lo suficientemente sensible como para detectar variaciones entre diferentes aspectos del sistema estudiado. Fue también relativamente independiente de la cantidad y la calidad de la información disponible. En el caso de Salta, el valor obtenido para el ISAS fue de 51 puntos en una escala de 0 a 100 cuyo umbral de aceptabilidad se estableció en 50 puntos. El cálculo del ISAS permitió identificar una serie de aspectos del sistema que requieren mejoras y optimización. Este índice puede ser una herramienta útil para evaluar y mejorar la sustentabilidad de los sistemas de gestión del agua y el saneamiento en la región.A comprehensive sustainability index for the assessment of water and sanitation management systems (WSMS) is presented. The index was based on a conceptual framework that perceives sustainability as a combination of territorial, temporal, and personal aspects. A set of sustainability indicators was selected in agreement with this framework, and the “Water and Sanitation Sustainability Index” (WASSI) was built. The WASSI was then used to assess the sustainability of the WSMS of the city of Salta, Argentina. Indicators were calculated with information gathered by several means including literature reviews, questionnaires, visits, sampling, and participatory workshops. The index was sensitive to detect variations between different aspects of the local WSMS. It was also relatively independent of the quantity and quality of the information available. In the case of Salta, the value obtained for the index was 51 points in a scale going from 0 to 100 in which the acceptability threshold was set at 50 points. The WASSI could be a useful tool to assess and improve the sustainability of regional water and sanitation management systems.Fil: Seghezzo, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones en Energía no Convencional; Argentina. Universidad Nacional de Salta; ArgentinaFil: Iribarnegaray, Martín Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones en Energía no Convencional; Argentina. Universidad Nacional de Salta; ArgentinaFil: Liberal, V. I.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones en Energía no Convencional; Argentina. Universidad Nacional de Salta; ArgentinaFil: Copa, F. R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones en Energía no Convencional; Argentina. Universidad Nacional de Salta; ArgentinaFil: Guerra Munizaga, M. S.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones en Energía no Convencional; Argentina. Universidad Nacional de Salta; ArgentinaFil: León, H. E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones en Energía no Convencional; Argentina. Universidad Nacional de Salta; ArgentinaFil: Ruíz, C. Y.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones en Energía no Convencional; Argentina. Universidad Nacional de Salta; Argentin

    In silico comparasion of 11 different radioisotopes for palliative treatment of bone metastases

    Get PDF
    Throughout the years, the palliative treatment of bone metastases using bone seeking radiotracers has been part of the therapeutic resources used in oncology. However, the choice of which bone seeking agent to use is not consensual. Computer simulation is a simple and practical solution to study and to compare a variety of radioisotopes. This study aimed to compare 11 different radioisotopes currently in use or under research. Hence, computational models were used to estimate the percentage of deoxyribonucleic acid damage, the probability of correct DNA repair, and the radiation-induced cellular effects post-irradiation. 223Ra alpha particles, 177Lu beta minus particles, and 170Tm beta minus particles induced the highest cell death of all investigated particles and radioisotopes. The cell survival fraction measured post-irradiation with beta minus particles emitted by 89Sr and 153Sm, was higher than 177Lu beta minus particles and 223Ra alpha particles. Findings reported here may prompt future in vitro and in vivo experiments comparing different radionuclides for palliative treatment of bone metastases

    Evaluación de la estabilidad de los lodos de las lagunas de estabilización de la zona norte de la ciudad de Salta

    Get PDF
    Se determinó la estabilidad de los lodos de las lagunas de estabilización de la zona Norte de la ciudad de Salta con la finalidad de elaborar recomendaciones para su gestión una vez clausurado el sistema de tratamiento. Se siguieron dos metodologías complementarias: el método normalizado de la Agencia de Protección Ambiental de los Estados Unidos y ensayos de estabilidad anaeróbica. Los resultados muestran que el lodo de las diferentes lagunas estudiadas se encuentra en general con un buen nivel de estabilización, lo que indicaría que el sistema operó de manera adecuada en su última etapa de funcionamiento.The stability of different samples of sludge from Waste Stabilization Ponds (WSP) was determined by means of two complementary methodologies: a standardized procedure developed by the U.S. Environmental Protection Agency and a laboratory test to measure anaerobic sludge stability. Results from this study can provide some guidelines to minimize environmental and social impacts after wastewater treatment systems such as WSP are definitely abandoned. Results obtained with both methods indicate that sludge from all WSP studied is well stabilized. This finding also suggests that the systems have been operating at low organic load in recent times.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

    Biochemical and Molecular Profiling of Wild Edible Mushrooms from Huila, Angola

    Get PDF
    The harvesting, processing, and sale of wild edible mushrooms (WEM) is a relevant economic activity in Angola and a good example of the use of non-wood forest products for food. Although there is deep traditional knowledge about the general properties of WEMs, a huge gap remains in detailed scientific knowledge. Thus, this study aimed to investigate the socio-economic importance of the species sold at local markets in Huila, Angola, from their molecular identification to the assessment of their nutritional, chemical, and bioactive profiles. From the eight WEM morphotypes studied, five were identified based on phenotypical and molecular approaches (four Russula spp., and Amanita loosei). The studied mushrooms proved to be a rich source of carbohydrates, proteins, and ashes, also presenting low amounts of fat. Chemical analyses further revealed mannitol as the main free sugar in all samples, and organic acids, namely, oxalic, quinic, malic, citric, and fumaric acids in low amounts. Additionally, the α-tocopherol isoform and monounsaturated fatty acids were predominant. Regarding phenolic acids, protocatechuic, p-hydroxybenzoic, p-coumaric, and cinnamic acids were detected in all mushroom hydroethanolic extracts, being responsible for their antioxidant, antibacterial, and antifungal activities. Our investigation contributes to the identification and knowledge of WEMs as important complementary food sources in Angola, some of which were reported for the first time, promoting their utilization as a basis of nutritional and functional ingredients, as being able to be part of a balanced diet and to be used in new bio-based formulations.info:eu-repo/semantics/publishedVersio

    Biochemical and Molecular Profiling of Wild Edible Mushrooms from Huila, Angola

    Get PDF
    The harvesting, processing, and sale of wild edible mushrooms (WEM) is a relevant economic activity in Angola and a good example of the use of non-wood forest products for food. Although there is deep traditional knowledge about the general properties of WEMs, a huge gap remains in detailed scientific knowledge. Thus, this study aimed to investigate the socio-economic importance of the species sold at local markets in Huila, Angola, from their molecular identification to the assessment of their nutritional, chemical, and bioactive profiles. From the eight WEM morphotypes studied, five were identified based on phenotypical and molecular approaches (four Russula spp., and Amanita loosei). The studied mushrooms proved to be a rich source of carbohydrates, proteins, and ashes, also presenting low amounts of fat. Chemical analyses further revealed mannitol as the main free sugar in all samples, and organic acids, namely, oxalic, quinic, malic, citric, and fumaric acids in low amounts. Additionally, the -tocopherol isoform and monounsaturated fatty acids were predominant. Regarding phenolic acids, protocatechuic, p-hydroxybenzoic, p-coumaric, and cinnamic acids were detected in all mushroom hydroethanolic extracts, being responsible for their antioxidant, antibacterial, and antifungal activities. Our investigation contributes to the identification and knowledge of WEMs as important complementary food sources in Angola, some of which were reported for the first time, promoting their utilization as a basis of nutritional and functional ingredients, as being able to be part of a balanced diet and to be used in new bio-based formulationsinfo:eu-repo/semantics/publishedVersio

    Clinical trial evidence supporting US Food and Drug Administration approval of novel cancer therapies between 2000 and 2016

    Get PDF
    Importance: Clinical trial evidence used to support drug approval is typically the only information on benefits and harms that patients and clinicians can use for decision-making when novel cancer therapies become available. Various evaluations have raised concern about the uncertainty surrounding these data, and a systematic investigation of the available information on treatment outcomes for cancer drugs approved by the US Food and Drug Administration (FDA) is warranted. Objective: To describe the clinical trial data available on treatment outcomes at the time of FDA approval of all novel cancer drugs approved for the first time between 2000 and 2016. Design, Setting, and Participants: This comparative effectiveness study analyzed randomized clinical trials and single-arm clinical trials of novel drugs approved for the first time to treat any type of cancer. Approval packages were obtained from drugs@FDA, a publicly available database containing information on drug and biologic products approved for human use in the US. Data from January 2000 to December 2016 were included in this study. Main Outcomes and Measures: Regulatory and clinical trial characteristics were described. For randomized clinical trials, summary treatment outcomes for overall survival, progression-free survival, and tumor response across all therapies were calculated, and median absolute survival increases were estimated. Tumor types and regulatory characteristics were assessed separately. Results: Between 2000 and 2016, 92 novel cancer drugs were approved by the FDA for 100 indications based on data from 127 clinical trials. The 127 clinical trials included a median of 191 participants (interquartile range [IQR], 106-448 participants). Overall, 65 clinical trials (51.2%) were randomized, and 95 clinical trials (74.8%) were open label. Of 100 indications, 44 indications underwent accelerated approval, 42 indications were for hematological cancers, and 58 indications were for solid tumors. Novel drugs had mean hazard ratios of 0.77 (95% CI, 0.73-0.81; I2 = 46%) for overall survival and 0.52 (95% CI, 0.47-0.57; I2 = 88%) for progression-free survival. The median tumor response, expressed as relative risk, was 2.37 (95% CI, 2.00-2.80; I2 = 91%). The median absolute survival benefit was 2.40 months (IQR, 1.25-3.89 months). Conclusions and Relevance: In this study, data available at the time of FDA drug approval indicated that novel cancer therapies were associated with substantial tumor responses but with prolonging median overall survival by only 2.40 months. Approval data from 17 years of clinical trials suggested that patients and clinicians typically had limited information available regarding the benefits of novel cancer treatments at market entry

    Aspectos institucionales para la evaluación de la sustentabilidad de la gestión del agua y el saneamiento en la provincia de Salta, Argentina

    Get PDF
    En el presente trabajo se calculó un Índice de Sustentabilidad Institucional (ISI) para tres de las instituciones consideradas clave en el marco de la gestión del agua y el saneamiento en la ciudad de Salta. La información necesaria para la confección del índice se obtuvo de encuestas específicas entregadas a las diferentes instituciones. Para contextualizar el estudio de caso, se presenta una síntesis del proceso de privatización del servicio de agua y saneamiento en la provincia de Salta. Los resultados obtenidos mostraron que la metodología es sensible para detectar áreas específicas a mejorar, constituyendo una herramienta potencialmente viable para analizar la sustentabilidad institucional en un marco conceptual definido.In this article we present an Institutional Sustainability Index (ISI) for three key institutions in the water and sanitation management system in the city of Salta, Argentina. Information for the construction of the index was obtained through questionnaires answered by representatives of the three institutions. A brief description of the history of the management system in Salta is provided to shed some light on the institutional context. Results obtained suggest that the methodology used was sensitive to detect differences between institutions, and between different aspects within them. The ISI could be a useful and innovative way of assessing the institutional sustainability of water and sanitation managment systems in the region.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

    Aspectos institucionales para la evaluación de la sustentabilidad de la gestión del agua y el saneamiento en la provincia de Salta, Argentina

    Get PDF
    En el presente trabajo se calculó un Índice de Sustentabilidad Institucional (ISI) para tres de las instituciones consideradas clave en el marco de la gestión del agua y el saneamiento en la ciudad de Salta. La información necesaria para la confección del índice se obtuvo de encuestas específicas entregadas a las diferentes instituciones. Para contextualizar el estudio de caso, se presenta una síntesis del proceso de privatización del servicio de agua y saneamiento en la provincia de Salta. Los resultados obtenidos mostraron que la metodología es sensible para detectar áreas específicas a mejorar, constituyendo una herramienta potencialmente viable para analizar la sustentabilidad institucional en un marco conceptual definido.In this article we present an Institutional Sustainability Index (ISI) for three key institutions in the water and sanitation management system in the city of Salta, Argentina. Information for the construction of the index was obtained through questionnaires answered by representatives of the three institutions. A brief description of the history of the management system in Salta is provided to shed some light on the institutional context. Results obtained suggest that the methodology used was sensitive to detect differences between institutions, and between different aspects within them. The ISI could be a useful and innovative way of assessing the institutional sustainability of water and sanitation managment systems in the region.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES
    corecore