428 research outputs found

    Analytical Model of Socio-Technical Sustainability of Dynamic Hypermedia Devices

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    Este artículo presenta un modelo analítico de sostenibilidad de redes socio-técnicas para la construcción colaborativa de conocimiento en contextos institucionales y organizacionales. El objetivo se centra en fundamentar una perspectiva teórica-metodológica a partir de la noción de “dispositivo hipermedial dinámico” (DHD). En lo metodológico, desde un posicionamiento sociotécnico, se realiza una revisión de los principales debates y perspectivas teóricas sobre la expansión de TIC en relación a la problemática a tratar. Luego se desarrollan propositivamente las componentes del modelo de sostenibilidad-DHD siguiendo sus cuatro dimensiones: social, institucional, tecnológica y textual. El diseño del modelo, no jerárquico y relacional, se estima a su vez beneficioso para orientar el proceso constructivo de este tipo de dispositivos. Además, puede colaborar de manera flexible para analizar transformaciones socio-tecnológicas en diversos contextos situados. Finalmente, la consistencia de los resultados analíticos a alcanzar podría ser efectiva, ya que es posible vincular: el carácter dinámico, relacional e interactivo de las características de una tecnología; las tensiones sociales y políticas existentes en el marco socio-institucional donde se desarrolla; las posibles formas de diseño participativo, en función de los requerimientos de una institución u organización; y la producción colaborativa en red, promoviendo responsabilidades de gestión organizacional.Este artigo apresenta um modelo analítico de sustentabilidade de redes sociotécnicas para a construção colaborativa de conhecimento em contextos institucionais/organizacionais. O objetivo é focado na fundamentação de uma perspectiva teórico-metodológica a partir da noção de “dispositivo hipermedial dinâmico” (DHD). No metodológico, a partir de um posicionamento sociotécnico, é feita uma revisão dos principais debates e perspectivas teóricas sobre a expansão de TIC em relação à problemática a ser tratada. Depois, são desenvolvidos propositivamente os componentes do modelo de sustentabilidade-DHD seguindo suas quatro dimensões: social, institucional, tecnológica e textual. O design do modelo, não hierárquico e relacional, é também considerado propício para orientar o processo construtivo deste tipo de dispositivos. Além disso, pode colaborar de forma flexível para analisar transformações sociais tecnológicas em diversos contextos. Finalmente, a consistência dos resultados analíticos a serem alcançados poderia ser efetiva, pois é possível vincular: o caráter dinâmico, relacional e interativo das características de uma tecnologia; as tensões sociais e políticas existentes no plano social institucional onde é desenvolvido; as possíveis formas de design participativo, em função dos requerimentos de uma instituição ou organização; e a produção colaborativa em rede, promovendo responsabilidades de gestão organizacional.This paper presents an analytical model of sustainable socio-technical networks for the collaborative knowledge building in organizational/institutional contexts. Its objective focuses on supporting a theoretic-methodological perspective based on the idea of a “dynamic hypermedia device” (DHD). With regard to the methodological aspect, from a socio-technical position, the main debates and theoretical perspectives about the expansion of information and communication technologies pertinent to the issue to be discussed are reviewed. Then the components of the sustainability-DHD model are developed proactively, following its four dimensions: social, institutional, technological and textual. The design of the model, nonhierarchical and relational, is considered beneficial to guide the building process of these kinds of devices. In addition, it can collaborate in a flexible way in order to analyze the sociotechnological transformations in diverse situational contexts. Finally, the consistency of the analytical results to be reached could be effective, since it is possible to connect: the dynamic, relational and interactive aspects of the technology’s characteristics; the social and political tensions within the socio-institutional framework in which it develops; the possible ways of participative design, as a function of the institution or organization’s requirements; and the networked collaborative production, promoting organizational management responsibilities.Fil: Andres, Gonzalo Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto Rosario de Investigaciones en Ciencias de la Educación. Universidad Nacional de Rosario. Instituto Rosario de Investigaciones en Ciencias de la Educación; ArgentinaFil: San Martin, Patricia Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto Rosario de Investigaciones en Ciencias de la Educación. Universidad Nacional de Rosario. Instituto Rosario de Investigaciones en Ciencias de la Educación; ArgentinaFil: Rodriguez, Guillermo L.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto Rosario de Investigaciones en Ciencias de la Educación. Universidad Nacional de Rosario. Instituto Rosario de Investigaciones en Ciencias de la Educación; Argentin

    High-k gadolinium scandate on Si obtained by high pressure sputtering from metal targets and in-situ plasma oxidation

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    This article studies the physical and electrical behavior of Gd2-xScxO3 layers grown by high pressure sputtering from metallic Gd and Sc targets. The aim is to obtain a high permittivity dielectric for microelectronic applications. The films were obtained by the deposition of a metallic nanolaminate of Gd and Sc alternating layers, which is afterwards in-situ oxidized by plasma. The oxide films obtained were close to stoichiometry, amorphous and with minimal interfacial regrowth. By fabricating metal-insulator-semiconductor capacitors we found that a moderate temperature annealing is needed to enhance permittivity, which reaches a high value of 32 while keeping moderate leakage. Finally, the feasibility of interface scavenging in this material with Ti gate electrodes is also demonstrated

    Phenoloxidase activity acts as a mosquito innate immune response against infection with semliki forest virus

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    Several components of the mosquito immune system including the RNA interference (RNAi), JAK/STAT, Toll and IMD pathways have previously been implicated in controlling arbovirus infections. In contrast, the role of the phenoloxidase (PO) cascade in mosquito antiviral immunity is unknown. Here we show that conditioned medium from the Aedes albopictus-derived U4.4 cell line contains a functional PO cascade, which is activated by the bacterium Escherichia coli and the arbovirus Semliki Forest virus (SFV) (Togaviridae; Alphavirus). Production of recombinant SFV expressing the PO cascade inhibitor Egf1.0 blocked PO activity in U4.4 cell- conditioned medium, which resulted in enhanced spread of SFV. Infection of adult female Aedes aegypti by feeding mosquitoes a bloodmeal containing Egf1.0-expressing SFV increased virus replication and mosquito mortality. Collectively, these results suggest the PO cascade of mosquitoes plays an important role in immune defence against arboviruses

    The role of sexually transmitted infections in male circumcision effectiveness against HIV – insights from clinical trial simulation

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    BACKGROUND: A landmark randomised trial of male circumcision (MC) in Orange Farm, South Africa recently showed a large and significant reduction in risk of HIV infection, reporting MC effectiveness of 61% (95% CI: 34%–77%). Additionally, two further randomised trials of MC in Kisumu, Kenya and Rakai, Uganda were recently stopped early to report 53% and 48% effectiveness, respectively. Since MC may protect against both HIV and certain sexually transmitted infections (STI), which are themselves cofactors of HIV infection, an important question is the extent to which this estimated effectiveness against HIV is mediated by the protective effect of circumcision against STI. The answer lies in the trial data if the appropriate statistical analyses can be identified to estimate the separate efficacies against HIV and STI, which combine to determine overall effectiveness. OBJECTIVES AND METHODS: Focusing on the MC trial in Kisumu, we used a stochastic prevention trial simulator (1) to determine whether statistical analyses can validly estimate efficacy, (2) to determine whether MC efficacy against STI alone can produce large effectiveness against HIV and (3) to estimate the fraction of all HIV infections prevented that are attributable to efficacy against STI when both efficacies combine. RESULTS: Valid estimation of separate efficacies against HIV and STI as well as MC effectiveness is feasible with available STI and HIV trial data, under Kisumu trial conditions. Under our parameter assumptions, high overall effectiveness of MC against HIV was observed only with a high MC efficacy against HIV and was not possible on the basis of MC efficacy against STI alone. The fraction of all HIV infections prevented which were attributable to MC efficacy against STI was small, except when efficacy of MC specifically against HIV was very low. In the three MC trials which reported between 48% and 61% effectiveness (combining STI and HIV efficacies), the fraction of HIV infections prevented in circumcised males which were attributable to STI was unlikely to be more than 10% to 20%. CONCLUSION: Estimation of efficacy, attributable fraction and effectiveness leads to improved understanding of trial results, gives trial results greater external validity and is essential to determine the broader public health impact of circumcision to men and women

    Mass measurements of As, Se and Br nuclei and their implication on the proton-neutron interaction strength towards the N=Z line

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    Mass measurements of the nuclides 69As, 70,71Se, and 71Br, produced via fragmentation of a 124Xe primary beam at the Fragment Separator (FRS) at GSI, have been performed with the multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) of the FRS Ion Catcher with an unprecedented mass resolving power of almost 1000000. Such high resolving power is the only way to achieve accurate results and resolve overlapping peaks of short-lived exotic nuclei, whose total number of accumulated events is always limited. For the nuclide 69As, this is the first direct mass measurement. A mass uncertainty of 22 keV was achieved with only ten events. For the nuclide 70Se, a mass uncertainty of 2.6 keV was obtained, corresponding to a relative accuracy of δm/m=4.0×10−8, with less than 500 events. The masses of the nuclides 71Se and 71Br have been measured with an uncertainty of 23 and 16 keV, respectively. Our results for the nuclides 70,71Se and 71Br are in good agreement with the 2016 Atomic Mass Evaluation, and our result for the nuclide 69As resolves the discrepancy between the previous indirect measurements. We measured also the mass of the molecule 14N15N40Ar (A=69) with a relative accuracy of δm/m=1.7×10−8, the highest yet achieved with an MR-TOF-MS. Our results show that the measured restrengthening of the proton-neutron interaction (δVpn) for odd-odd nuclei along the N=Z line above Z=29 (recently extended to Z=37) is hardly evident at the N−Z=2 line, and not evident at the N−Z=4 line. Nevertheless, detailed structure of δVpn along the N−Z=2 and N−Z=4 lines, confirmed by our mass measurements, may provide a hint regarding the ongoing ≈500 keV discrepancy in the mass value of the nuclide 70Br, which prevents including it in the world average of Ft value for superallowed 0+→0+β decays. The reported work sets the stage for mass measurements with the FRS Ion Catcher of nuclei at and beyond the N=Z line in the same region of the nuclear chart, including the nuclide 70Br.peerReviewe

    The Advanced Virgo+ status

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    The gravitational wave detector Advanced Virgo+ is currently in the commissioning phase in view of the fourth Observing Run (O4). The major upgrades with respect to the Advanced Virgo configuration are the implementation of an additional recycling cavity, the Signal Recycling cavity (SRC), at the output of the interferometer to broaden the sensitivity band and the Frequency Dependent Squeezing (FDS) to reduce quantum noise at all frequencies. The main difference of the Advanced Virgo + detector with respect to the LIGO detectors is the presence of marginally stable recycling cavities, with respect to the stable recycling cavities present in the LIGO detectors, which increases the difficulties in controlling the interferometer in presence of defects (both thermal and cold defects). This work will focus on the interferometer commissioning, highlighting the control challenges to maintain the detector in the working point which maximizes the sensitivity and the duty cycle for scientific data taking
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