940 research outputs found
On autonomic platform-as-a-service: characterisation and conceptual model
In this position paper, we envision a Platform-as-a-Service conceptual and architectural solution for large-scale and data intensive applications. Our architectural approach is based on autonomic principles, therefore, its ultimate goal is to reduce human intervention, the cost, and the perceived complexity by enabling the autonomic platform to manage such applications itself in accordance with highlevel policies. Such policies allow the platform to (i) interpret the application specifications; (ii) to map the specifications onto the target computing infrastructure, so that the applications are executed and their Quality of Service (QoS), as specified in their SLA, enforced; and, most importantly, (iii) to adapt automatically such previously established mappings when unexpected behaviours violate the expected. Such adaptations may involve modifications in the arrangement of the computational infrastructure, i.e. by re-designing a different communication network topology that dictates how computational resources interact, or even the live-migration to a different computational infrastructure. The ultimate goal of these challenges is to (de)provision computational machines, storage and networking links and their required topologies in order to supply for the application the virtualised infrastructure that better meets the SLAs. Generic architectural blueprints and principles have been provided for designing and implementing an autonomic computing system.We revisit them in order to provide a customised and specific viewfor PaaS platforms and integrate emerging paradigms such as DevOps for automate deployments, Monitoring as a Service for accurate and large-scale monitoring, or well-known formalisms such as Petri Nets for building performance models
Internet-based psychoeducation for bipolar disorder: a qualitative analysis of feasibility, acceptability and impact
<p>Background: In a recent exploratory randomised trial we found that a novel, internet-based psychoeducation programme for bipolar disorder (Beating Bipolar) was relatively easy to deliver and had a modest effect on psychological quality of life. We sought to explore the experiences of participants with respect to feasibility, acceptability and impact of Beating Bipolar.</p>
<p>Methods: Participants were invited to take part in a semi-structured interview. Thematic analysis techniques were employed; to explore and describe participants’ experiences, the data were analysed for emerging themes which were identified and coded.</p>
<p>Results: The programme was feasible to deliver and acceptable to participants where they felt comfortable using a computer. It was found to impact upon insight into illness, health behaviour, personal routines and positive attitudes towards medication. Many participants regarded the programme as likely to be most beneficial for those recently diagnosed.</p>
<p>Conclusions: An online psychoeducation package for bipolar disorder, such as Beating Bipolar, is feasible and acceptable to patients, has a positive impact on self-management behaviours and may be particularly suited to early intervention. Alternative (non-internet) formats should also be made available to patients.</p>
BAORadio : Cartographie 3D de la distribution de gaz H dans l'Univers
3D mapping of matter distribution in the universe through the 21 cm radio
emission of atomic hydrogen is a complementary approach to optical surveys for
the study of the Large Scale Structures, in particular for measuring the BAO
(Baryon Acoustic Oscillation) scale up to redshifts z <~ 3 and constrain dark
energy. We propose to carry such a survey through a novel method, called
intensity mapping, without detecting individual galaxies radio emission. This
method requires a wide band instrument, 100 MHz or larger, and multiple beams,
while a rather modest angular resolution of 10 arcmin would be sufficient. The
instrument would have a few thousand square meters of collecting area and few
hundreds of simultaneous beams. These constraints could be fulfilled with a
dense array of receivers in interferometric mode, or a phased array at the
focal plane of a large antenna
Modelling the influence of RKIP on the ERK signalling pathway using the stochastic process algebra PEPA
This paper examines the influence of the Raf Kinase Inhibitor Protein (RKIP) on the Extracellular signal Regulated Kinase (ERK) signalling pathway [5] through modelling in a Markovian process algebra, PEPA [11]. Two models of the system are presented, a reagent-centric view and a pathway-centric view. The models capture functionality at the level of subpathway, rather than at a molecular level. Each model affords a different perspective of the pathway and analysis. We demonstrate the two models to be formally equivalent using the timing-aware bisimulation defined over PEPA models and discuss the biological significance
Study of the conversion of CH4/H2S mixtures at different pressures
Due to the different scenarios where sour gas is present, its composition can be different and, therefore, it can be exploited through different processes, being combustion one of them. In this context, this work deals with the oxidation of CH4 and H2S at different pressures and under a wide variety of conditions. The oxidation has been evaluated experimentally in two different flow reactor set-ups, one working at atmospheric pressure and another one operating from atmospheric to high pressures (40 bar). Different CH4/H2S mixtures have been tested, together with different oxygen concentrations and in the temperature range of 500–1400 K. The experimental results obtained show that the oxidation of the CH4/H2S mixtures is shifted to lower temperatures as pressure increases, obtaining the same trends at atmospheric pressure in both experimental set-ups. H2S oxidation occurs prior to CH4 oxidation at all conditions, providing radicals to the system that promote CH4 oxidation to lower temperatures (compared to neat CH4 oxidation). This effect is more relevant as pressure increases. H2S oxidation is inhibited by CH4 at atmospheric pressure, being more noticeable when the CH4/H2S ratio is higher. At higher pressures, the H2S conversion occurs similarly in the absence or presence of CH4. The experimental results have been modeled with an updated kinetic model from previous works from the literature, which, in general, matches well the experimental trends, while some discrepancies between experimental and modeling results at atmospheric pressure and 40 bar are found in the conversion of H2S and CH4
Propiedades dieléctricas y mecánicas del polietileno de alta densidad (HDPE) reforzado con neumáticos fuera de uso (GTR)
La eliminación o reciclado de los neumáticos utilizados constituye hoy en día un grave problema medioambiental, y aunque se ha avanzado en su estudio, existiendo diversos metodos para su reciclaje como la trituración mecánica, que separa el caucho vulcanizado del acero y las fibras permitiendo su utilización en diversas aplicaciones industriales, el gran volumen de neumáticos hace necesario encontrar nuevas fórmulas que permitan ayudar a la eliminación del excedente de este material de rechazo. En este artículo se propone una nueva forma para el aprovechamiento del neumático reutilizado (GTR), utilizando el polvo de este neumático como refuerzo y el polietileno de alta densidad reciclado (HDPE) como matriz, creando un nuevo compuesto, el cual para ser útil en la industria debe mantener dentro de unos valores aceptables las propiedades dieléctricas y mecánicas del polímero original. Concretamente, el polvo de los neumáticos reutilizados resultado de los procesos industriales de molienda, es separado por tamizado en tres categorías de tamaño de partículas (<200 μm, 200-500μm, y >500 μm), y mezclado con el HDPE en diversas concentraciones (0%, 5%,10%, 20%, 40%, 50% y 70% de GTR) para así determinar su comportamiento mediante los ensayos dieléctricos y mecánicos, realizados en un rango de temperaturas que varía desde los 30ºC hasta los 130ºC, y con unas frecuencias desde 1·10-2 Hz, hasta 1·107 Hz. Mediante los ensayos dieléctricos se han analizado la permitividad, la conductividad, el factor de pérdidas dieléctricas, el modulo dieléctrico etc., mientras que con los ensayos mecánicos de Tracción-Deformación, se han analizado el Modulo de Young, la tensión a la tracción, y la elongación y energía a la rotura
Large excess of heavy nitrogen in both hydrogen cyanide and cyanogen from comet 17P/Holmes
From millimeter and optical observations of the Jupiter-family comet
17P/Holmes performed soon after its huge outburst of October 24, 2007, we
derive 14 N/15N = 139 +/- 26 in HCN, and 14N/15N = 165 +/- 40 in CN,
establishing that HCN has the same non-terrestrial isotopic composition as CN.
The same conclusion is obtained for the long-period comet C/1995 O1 (Hale-Bopp)
after a reanalysis of previously published measurements. These results are
compatible with HCN being the prime parent of CN in cometary atmospheres. The
15N excess relative to the Earth atmospheric value indicates that N-bearing
volatiles in the solar nebula underwent important N isotopic fractionation at
some stage of Solar System formation. HCN molecules never isotopically
equilibrated with the main nitrogen reservoir in the solar nebula before being
incorporated in Oort-cloud and Kuiper-belt comets. The 12C/13C ratios in HCN
and CN are measured to be consistent with the terrestrial value.Comment: Accepted for publication in the Astrophysical Journal (Letters) 4
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Efecto de pretratamientos desvulcanizantes y de aditivos en materiales compuestos con matriz de HDPE y neumáticos fuera de uso
La gestión de los neumáticos al final de su ciclo de vidaprecisa soluciones para potenciar su reutilización y reciclado.Un paso previo consiste en la pulverización de losneumáticos por parte de empresas especializadas. La incorporaciónde este granulado como refuerzo en matricestermoplásticas se ha propuesto como método de valorizacióndel polvo de neumático. Este sistema se ve limitadopor la incompatibilidad entre matriz y refuerzo. Recientemente,un nuevo polvo de neumático, denominado comercialmente “desvulcanizado” ha aparecido en el mercado.En este artículo se comparan materiales compuestosformulados con polvo de neumático desvulcanizado conlos obtenidos con el mismo material sin tratamiento enmatriz de polietileno de alta densidad. También se estudiael efecto de distintos métodos de mezclado, del uso deaditivos dispersantes y del tamaño de partícula
Nanoscale Charge Density and Dynamics in Graphene Oxide
Graphene oxide (GO) is widely used as a component in thin film optoelectronic device structures for practical reasons because its electronic and optical properties can be controlled. Progress critically depends on elucidating the nanoscale electronic structure of GO. However, direct experimental access is challenging because of its disordered and nonconductive character. Here, we quantitatively mapped the nanoscopic charge distribution and charge dynamics of an individual GO sheet by using Kelvin probe force microscopy (KPFM). Charge domains are identified, presenting important charge interactions below distances of 20 nm. Charge dynamics with very long relaxation times of at least several hours and a logarithmic decay of the time correlation function are in excellent agreement with Monte Carlo simulations, revealing an universal hopping transport mechanism best described by Efros-Shklovskii''s law. © 2021 The Authors. Published by American Chemical Society
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