195 research outputs found

    Design of an adaptive-rate video-streaming service with different classes of users

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    The provision of end-to-end Quality of Service (QoS) for multimedia services over IP-based networks is already an open issue. To achieve this goal, service providers need to manage Service Level Agreements (SLAs), which specify parameters of the services operation such as availability and performance. Additional mechanisms are needed to quantitatively evaluate the user-level SLA parameters. This work is focused on the evaluation and assessment of different design options of an adaptive VoD service providing several classes of users and fulfilling the SLA commitments. Based on a straightforward Markov Chain, Markov-Reward Chain (MRC) models are developed in order to obtain various QoS measures of the adaptive VoD service. The MRC model has a clear understanding with the design and operation of the VoD system.5th IFIP International Conference on Network Control & Engineering for QoS, Security and MobilityRed de Universidades con Carreras en Informática (RedUNCI

    Design of an adaptive-rate video-streaming service with different classes of users

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    The provision of end-to-end Quality of Service (QoS) for multimedia services over IP-based networks is already an open issue. To achieve this goal, service providers need to manage Service Level Agreements (SLAs), which specify parameters of the services operation such as availability and performance. Additional mechanisms are needed to quantitatively evaluate the user-level SLA parameters. This work is focused on the evaluation and assessment of different design options of an adaptive VoD service providing several classes of users and fulfilling the SLA commitments. Based on a straightforward Markov Chain, Markov-Reward Chain (MRC) models are developed in order to obtain various QoS measures of the adaptive VoD service. The MRC model has a clear understanding with the design and operation of the VoD system.5th IFIP International Conference on Network Control & Engineering for QoS, Security and MobilityRed de Universidades con Carreras en Informática (RedUNCI

    Design of an adaptive-rate video-streaming service with different classes of users

    Get PDF
    The provision of end-to-end Quality of Service (QoS) for multimedia services over IP-based networks is already an open issue. To achieve this goal, service providers need to manage Service Level Agreements (SLAs), which specify parameters of the services operation such as availability and performance. Additional mechanisms are needed to quantitatively evaluate the user-level SLA parameters. This work is focused on the evaluation and assessment of different design options of an adaptive VoD service providing several classes of users and fulfilling the SLA commitments. Based on a straightforward Markov Chain, Markov-Reward Chain (MRC) models are developed in order to obtain various QoS measures of the adaptive VoD service. The MRC model has a clear understanding with the design and operation of the VoD system.5th IFIP International Conference on Network Control & Engineering for QoS, Security and MobilityRed de Universidades con Carreras en Informática (RedUNCI

    Piezoelectric and magnetically responsive biodegradable composites with tailored porous morphology for biotechnological applications

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    The biomedical area in the scope of tissue regeneration pursues the development of advanced materials that can target biomimetic approaches and, ideally, have an active role in the environment they are placed in. This active role can be related to or driven by morphological, mechanical, electrical, or magnetic stimuli, among others. This work reports on the development of active biomaterials based on poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid), PHBV, a piezoelectric and biodegradable polymer, for tissue regeneration application by tailoring its morphology and functional response. PHBV films with different porosities were obtained using the solvent casting method, resorting to high-boiling-point solvents, as N,N-dimethylformamide (DMF) and dimethylsulfoxide (DMSO), and the combination of chloroform (CF) and DMF for polymer dissolution. Furthermore, magnetoelectric biomaterials were obtained through the combination of the piezoelectric PHBV with magnetostrictive iron oxide (Fe3O4) nanoparticles. Independently of the morphology or filler content, all biomaterials proved to be suitable for biomedical applications.This work was supported by national funds through the Fundação para a Ciência e Tecnologia (FCT) and by ERDF through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) in the framework of the Strategic Programs UID/FIS/04650/2020, and project PTDC/BTM-MAT/28237/2017. TMA thank FCT for the research grant: SFRH/BD/141136/2018, VC for the junior researcher contract (DL57/2016) and CR for the contract under the Stimulus of Scientific Employment, Individual Support (CEECIND) – 3 rd Edition (2020.04163.CEECIND). Finally, the authors acknowledge funding by Spanish State Research Agency (AEI) and the European Regional Development Fund (ERFD) through the project PID2019-106099RBC43/AEI/10.13039/501100011033 and from the Basque Government Industry Departments under the ELKARTEK program

    Clinical trials and Haemophilia during the COVID-19 pandemic: Madrid's experience

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    This is the peer reviewed version of the following article: "Clinical trials and Haemophilia during the COVID‐19 pandemic: Madrid's experience". Haemophilia (2020): 16 May, which has been published in final form at https://doi.org/10.1111/hae.14055. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Version

    Diverse strategies for copper production in Chalcolithic Iberia

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    Our understanding of early copper metallurgy in the Iberian Peninsula is mostly based on analysis from wellstudied regions in the Southeast and Southwest. This paper focuses on two recently recovered Chalcolithic metallurgical assemblages outside these traditional research foci: two slagged crucibles from Lugar Viejo III (Zaragoza) and two large slag cakes from Cueva del Canaveralejo ˜ (Cordoba). ´ Analysis of the compositions and microstructures of the artifacts using optical microscopy and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) suggests they are related to primary copper production, namely smelting in cruciblefurnaces under relatively oxidizing conditions, as is standard for this period. The slag layers on crucibles from Lugar Viejo indicate the production of copper with minor amounts of arsenic, also typical for this period. Of special note is the use of organic temper in the crucibles from Lugar Viejo, a practice found at the nearby site of Moncín but rare at other sites in Iberia. However, the slags from Cueva del Canaveralejo ˜ are atypical in their large size (approx. 125 g each), fayalitic composition, unusual efficiency as demonstrated by a low copper content, and lack of arsenic; furthermore, the high sulfur content raises the possibility of the use of sulfidic ores. Results from both sites are compared against published data from well-known sites such as Los Millares, Las Pilas, Almizaraque, and Bauma del Serrat del Pont. The new data from Lugar Viejo and Cueva del Canaveralejo ˜ reinforce the interpretation of metallurgy in the Iberian Peninsula as a low-skilled, conservative technology but also indicate the need for more research into regional variations. (See upplementary Data 1 for a summary in Spanish)

    Implicaciones del desmantelamiento de un foco de compra y consumo de drogas en Valencia

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    Desde el año 2003 la Fundación Salud y Comunidad (FSC), con el patrocinio principal de la Generalitat Valenciana, ha trabajado en la zona de 'Las Cañas', lugar que ha sido el foco de compraventa de drogas más activo de Valencia, realizando programas de contacto y de reducción de riesgos y daños, con más de 9.000 usuarios diferentes atendidos. En el año 2008 se realizó una intervención policial en el área con el objetivo de reducir la oferta de drogas. La falta de coordinación y comunicación entre la policía y los agentes sanitarios y sociales generó una situación potencialmente muy peligrosa para la salud de los drogodependientes y el impacto comunitario, lo que motivó una investigación de urgencia para medir y valorar el impacto de dicha actuación. Los resultados, interpretados junto con los datos asistenciales de los años 2007, 2008 y 2009, sugieren que la intervención policial no disminuyó ni difi cultó el acceso a las sustancias como se esperaba, aunque se transformó la estructura de la oferta y la demanda, fomentando el uso de heroína y cocaína inyectada, frente a la anteriormente mayoritaria, y estimulando nuevos puntos de compraventa en otras áreas de la ciudad.Since 2003 Fundación Salud y Comunidad (FSC), under the auspices of the Valencian Regional Government, has been working in the area of 'Las Cañas' that has become the most active drug sale and purchase focal point in Valencia. Outreach programs were started to reduce risks and harm, with more than 9,000 different users helped. In 2008 police action took place in the area with the goal of reducing drug supply. The lack of coordination and communication between the police and health and social agents working in the area prompted an urgent investigation to measure and assess the impact of such action on the health of drug addicts and in the community. The results, interpreted together with data from the service records for the years 2007, 2008 and 2009, suggest that the police actions did not reduce nor hinder the access to substances as expected, although the structure of the supply and demand did indeed change, favouring the use of injected (instead of inhaled) heroin and cocaine, and stimulating new sale and purchase points in other areas of the city

    Study of platelet kinetics in immune thrombocytopenia to predict splenectomy response

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    Despite the efficacy of splenectomy for chronic immune thrombocytopenia (ITP), its considerable failure rate and its possible related complications prove the need for further research into potential predictors of response. The platelet sequestration site determined by 111In-labelled autologous platelet scintigraphy has been proposed to predict splenectomy outcome, but without standardisation in clinical practice. Here, we conducted a single-centre study by analysing a cohort of splenectomised patients with ITP in whom 111In-scintigraphy was performed at La Paz University Hospital in Madrid to evaluate the predictive value of the platelet kinetic studies. We also studied other factors that could impact the splenectomy outcome, such as patient and platelet characteristics. A total of 51 patients were splenectomised, and 82.3% responded. The splenic sequestration pattern predicted a higher rate of complete response up to 12 months after splenectomy (p = 0.005), with 90% sensitivity and 77% specificity. Neither age, comorbidities, therapy lines nor previous response to them showed any association with response. Results from the platelet characteristics analysis revealed a significant loss of sialic acid in platelets from the non-responding patients compared with those who maintained a response (p = 0.0017). Our findings highlight the value of splenic sequestration as an independent predictor of splenectomy respons

    The importance of platelet glycoside residues in the haemostasis of patients with immune thrombocytopaenia

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    Loss of sialic acid from the carbohydrate side chains of platelet glycoproteins can affect platelet clearance, a proposed mechanism involved in the etiopathogenesis of immune thrombocy-topaenia (ITP). We aimed to assess whether changes in platelet glycosylation in patients with ITP affected platelet counts, function, and apoptosis. This observational, prospective, and transversal study included 82 patients with chronic primary ITP and 115 healthy controls. We measured platelet activation markers and assayed platelet glycosylation and caspase activity, analysing samples using flow cytometry. Platelets from patients with ITP with a platelet count <30 × 103/µL presented less sialic acid. Levels of α1,6-fucose (a glycan residue that can directly regulate antibody-dependent cellular cytotoxicity) and α-mannose (which can be recognised by mannose-binding-lectin and acti-vate the complement pathway) were increased in the platelets from these patients. Platelet surface exposure of other glycoside residues due to sialic acid loss inversely correlated with platelet count and the ability to be activated. Moreover, loss of sialic acid induced the ingestion of platelets by human hepatome HepG2 cells. Changes in glycoside composition of glycoproteins on the platelets’ surface impaired their functional capacity and increased their apoptosis. These changes in platelet glycoside residues appeared to be related to ITP severity.This research was funded by FIS-Fondos FEDER PI19/00631, FIS-Fondos FEDER PI19/00772 and Platelet Disorder Support Associatio
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