A Time-driven Data Placement Strategy for a Scientific Workflow Combining Edge Computing and Cloud Computing

Compared to traditional distributed computing environments such as grids, cloud computing provides a more cost-effective way to deploy scientific workflows. Each task of a scientific workflow requires several large datasets that are located in different datacenters from the cloud computing environment, resulting in serious data transmission delays. Edge computing reduces the data transmission delays and supports the fixed storing manner for scientific workflow private datasets, but there is a bottleneck in its storage capacity. It is a challenge to combine the advantages of both edge computing and cloud computing to rationalize the data placement of scientific workflow, and optimize the data transmission time across different datacenters. Traditional data placement strategies maintain load balancing with a given number of datacenters, which results in a large data transmission time. In this study, a self-adaptive discrete particle swarm optimization algorithm with genetic algorithm operators (GA-DPSO) was proposed to optimize the data transmission time when placing data for a scientific workflow. This approach considered the characteristics of data placement combining edge computing and cloud computing. In addition, it considered the impact factors impacting transmission delay, such as the band-width between datacenters, the number of edge datacenters, and the storage capacity of edge datacenters. The crossover operator and mutation operator of the genetic algorithm were adopted to avoid the premature convergence of the traditional particle swarm optimization algorithm, which enhanced the diversity of population evolution and effectively reduced the data transmission time. The experimental results show that the data placement strategy based on GA-DPSO can effectively reduce the data transmission time during workflow execution combining edge computing and cloud computing

The seasonal distribution of a highly commercial fish is related to ontogenetic changes in its feeding strategy

Improving the knowledge on the biology, ecology and distribution of marine resources exploited by fisheries is necessary to achieve population recovery and sustainable fisheries management. European hake (Merluccius merluccius) is one of the most important target species in the Mediterranean Sea and is largely overexploited by industrial fisheries. Here, we used two methodological approaches to further investigate the seasonal variation in the spatial distribution of European hake considering ontogenetic changes and trophic ecology in the western Mediterranean Sea. Our main aim was to explore if spatial changes in hake distribution were related to trophic behavior, in addition to key environmental factors. We employed a hierarchical Bayesian species distribution modeling approach (B-SDM), using spatial data from two oceanographic surveys conducted during winter and summer. We analyzed how the environmental variables, together with abundance and mean weight distribution of the main preys identified for European hake, affected the seasonal distribution of the species. Results revealed clear differences in the distribution of the European hake between seasons, which were indeed partially correlated to the distribution of their main preys, in addition to the environment. Stable isotope values and Bayesian isotopic mixing models (MixSIAR) revealed substantial seasonal and ontogenetic differences in trophic habits of European hake, partly matching the spatial distribution results. These findings could have implications for a future seasonal-based adaptive fisheries management, as local depletion of prey, or variation in size and condition may affect European hake presence in this area. Moreover, this study illustrates how the sequential application of methodologies provides a more holistic understanding of species seasonality, which is essential to understand the phenological processes of exploited species and their potential shifts due to environmental changes.Postprin

Intoxicación por litio desencadenada por un proceso febril. A propósito de un caso

IntroducciónEl litio es un fármaco muy utilizado en el trastorno bipolar tipo I. El principal problema de su utilización deriva del estrecho margen terapéutico, que aconseja la monitorización de sus concentraciones plasmáticas, así como prestar atención a las interacciones con otros fármacos, a las medidas dietéticas (dietas hiposódicas y otras pérdidas de sodio asociadas con diarreas o pérdidas de electrólitos) y a la hipovolemia, con el fin de evitar su toxicidad en sobredosificación1. Su mecanismo de acción se desconoce, aunque es probable que ejerza su acción desde dentro de la propia célula por desplazamiento del sodio, potasio, magnesio o calcio. Se sabe que inhibe la liberación de la dopamina y noradrenalina (de ahí su acción antimaníaca) y aumenta la acción de la serotonina.Caso clínicoPaciente varón de 69 años de edad con antecedentes de hipertensión arterial, trastorno bipolar desde hacía 12 años con predominio de síntomas depresivos, extrapiramidalismo medicamentoso (con alteraciones en la marcha, temblor de reposo, inestabilidad y caídas frecuentes, sin claro deterioro cognitivo) desde hacía 4 años. Actualmente seguía tratamiento con parmipexol 0,7 mg (1 comprimido/8 h), levodopa- carbidopa 25/100 mg (1 comprimido/ 8 h), carbonato de litio 400 mg (2 comprimidos/24 h), atenolol 100 mg (1 comprimido/24 h), enalaprilo 20 mg más hidroclorotiacida 12,5 mg (1 comprimido/ 24 h) y clorhidrato de maprotilina 75 (1,5 comprimido/24 h). Se le visitó en su domicilio por presentar malestar general, fiebre y hematuria macroscópica. Se le practicó multistix, que fue compatible con infección urinaria, y se inició tratamiento con amoxicilina-ácido clavulánico (500 mg/8 h). A las 48 h se le revaluó y se detectó en la exploración aumento de la rigidez y dificultad para moverse, junto con rueda dentada. Se decidió mantener el tratamiento y volver a evaluar al paciente al término de la medicación. Tras 10 días de tratamiento antibiótico mejoró su estado general y disminuyó la rigidez, pero persistía la febrícula vespertina. A los 5 días de finalizar el tratamiento antibiótico el paciente fue remitido al hospital por reaparición de fiebre elevada (sin evidencia de foco infeccioso en la exploración) junto con bradipsiquia, torpeza en la marcha, desorientación y temblores.En la exploración neurológica inicial en el hospital destacaron una puntuación de Glasgow de 10, estupor, bradipsiquia, trastorno del lenguaje (en comprensión y nominación), sin signos de afección piramidal. Los pares craneales no pudieron valorarse por falta de colaboración del paciente, que presentaba mioclonías de acción generalizadas sin fasciculaciones, así como reflejo palpebral hiperexaltado, reflejo osteotendinoso de 5/5 y reflejo cutaneoplantar en flexión. El resto de la exploración física por aparatos fue normal. En la analítica destacaban: creatinina de 1,5 mg/dl, creatincinasa de 278 U/l, lactatodeshidrogenasa de 543 U/l, proteína C reactiva de 37 mg/l y litemia de 2,15 mmol/l (rango terapéutico, 0,7-1,4); el resto de la bioquímica, hemograma, coagulación y hormonas tiroideas eran normales. En cuanto a la microbiología, el urocultivo, los hemocultivos y el estudio del líquido cefalorraquídeo fueron normales. Por lo que se refiere a las pruebas de imagen, tanto la radiografía de tórax como la tomografía computarizada craneal resultaron normales. En el electrocardiograma destacó un alargamiento del QT.Durante su ingreso presentó hipotensión arterial que requirió la administración de expansores del plasma y dopamina en perfusión. Tras proceder a la retirada del litio, dada la intoxicación moderada que presentaba el paciente, se apreció una mejoría del estado general y neurológico del paciente, que se resolvieron por completo cuando se le dio de alta.Discusión y conclusionesLas interacciones más peligrosas del litio se producen con los diuréticos tiacídicos (que aumentan las concentraciones plasmáticas del litio, por lo que se recomienda reducir la dosis de éste en un 30-50%) y con los antiinflamatorios no esteroideos (que tienden a reducir la depuración renal del litio aumentando así la concentración sérica; como alternativa se aconseja administrar paracetamol o ácido acetilsalicílico)2. Los diuréticos de asa y ahorradores de potasio también pueden interaccionar, aunque con menor relevancia. Se ha descrito neurotoxicidad con el uso combinado de litio y fluoxetina, neurolépticos, antihipertensivos (enalapril), carbamacepina y metildopa. Existen comunicaciones de interacción con antagonistas del calcio (verapamilo, diltiazem), antimicrobianos (metronidazol, espectinomicina), xantinas (teofilinas), quimioterápicos (cisplatino) y estimulantes centrales (mazindol)3.En este caso, el paciente se mantuvo estable a pesar de los múltiples fármacos que utilizaba y sus posibles interacciones, hasta presentar el proceso febril que desencadenó una intoxicación moderada por litio. Atendiendo a los valores de litemia, las intoxicaciones se clasifican en leves (1,5-2 mEq/l), moderadas (2-2,5 mEq/l) y graves (> 2,5 mEq/l). De los síntomas y signos de intoxicación moderada el paciente presentó los siguientes: estupor, mioclonías, reflejos osteotendinosos exaltados, hipotensión arterial y trastornos en la conducción electrocardiográfica4.Es imprecindible prestar gran atención a todos los procesos agudos que pueden alterar el equilibrio que mantienen los pacientes polimedicados y con fármacos con muy estrecho margen terapéutico.Nuestro agradecimiento a Avelina Magallón Fernández, Félix Fernández Suárez y Carlos J. Vallés Paulés

Resultados organizacionales y formación

Es común aceptar el valor de la formación de los empleados de cara a la mejora de la competitividad de las empresas, especialmente en una economía cada vez más abierta y avanzada tecnológicamente como es la actual. Son muchos los trabajos que han analizado empíricamente la relación entre formación de empleados y resultados organizacionales sin embargo, la evidencia empírica respecto del efecto positivo de la formación en el rendimiento de las empresas no es concluyente. Con el objetivo de dar una explicación a la ambigüedad observada en esta relación, planteamos el estudio de la formación y su efecto en los resultados de la empresa desde la perspectiva institucional. Apoyándonos en este marco teórico explicativo, se constata que hay factores de contexto que actúan como presiones para las empresas de cara a la decisión de realizar acciones formativas, lo que nos permitirá exponer una explicación a la controvertida y débil relación observada entre formación y resultados de la empresa.Currently, training is widely accepted as an important tool to help firms to improve their human resources and so increase its competitiveness. Despite the relationship between training and organizational results having been largely assessed, most empirical studies show paradoxical effects. The main purpose of this paper is to explore possible theories which could explain said results, and with this in mind, a different approach, the institutional theory, has been used to study the relationship between training and organizational results

Towards video streaming in IoT environments: vehicular communication perspective

Multimedia oriented Internet of Things (IoT) enables pervasive and real-time communication of video, audio and image data among devices in an immediate surroundings. Today's vehicles have the capability of supporting real time multimedia acquisition. Vehicles with high illuminating infrared cameras and customized sensors can communicate with other on-road devices using dedicated short-range communication (DSRC) and 5G enabled communication technologies. Real time incidence of both urban and highway vehicular traffic environment can be captured and transmitted using vehicle-to-vehicle and vehicle-to-infrastructure communication modes. Video streaming in vehicular IoT (VSV-IoT) environments is in growing stage with several challenges that need to be addressed ranging from limited resources in IoT devices, intermittent connection in vehicular networks, heterogeneous devices, dynamism and scalability in video encoding, bandwidth underutilization in video delivery, and attaining application-precise quality of service in video streaming. In this context, this paper presents a comprehensive review on video streaming in IoT environments focusing on vehicular communication perspective. Specifically, significance of video streaming in vehicular IoT environments is highlighted focusing on integration of vehicular communication with 5G enabled IoT technologies, and smart city oriented application areas for VSV-IoT. A taxonomy is presented for the classification of related literature on video streaming in vehicular network environments. Following the taxonomy, critical review of literature is performed focusing on major functional model, strengths and weaknesses. Metrics for video streaming in vehicular IoT environments are derived and comparatively analyzed in terms of their usage and evaluation capabilities. Open research challenges in VSV-IoT are identified as future directions of research in the area. The survey would benefit both IoT and vehicle industry practitioners and researchers, in terms of augmenting understanding of vehicular video streaming and its IoT related trends and issues

Conversion of CO2 by non- thermal inductively-coupled plasma catalysis

CO2 decomposition is a very strongly endothermic reaction where very high temperatures are required to thermally dissociate CO2. Radio frequency inductively-coupled plasma enables to selectively activate and dissociate CO2 at room temperature. Tuning the flow rate and the frequency of the radio frequency inductively-coupled plasma gives high yields of CO under mild conditions. Finally the discovery of a plasma catalytic effect has been demonstrated for CO2 dissociation that shows a significant increase of the CO yield by metallic meshes. The metallic meshes become catalysts under exposure to plasma to activate the recombination reaction of atomic O to yield O2, thereby reducing the reaction to convert CO back to CO2. Inductively-coupled hybrid plasma catalysis allows access to study and to utilize high CO2 conversion in a non-thermal plasma regime. This advance offers opportunities to investigate the possibility to use radio frequency inductively-coupled plasma to store superfluous renewable electricity into high-valuable CO in time where the price of renewable electricity is plunging.</p

Controlling suction by vapour equilibrium technique at different temperatures, application to the determination of the water retention properties of MX80 clay

Problems related to unsaturated soils are frequently encountered in geotechnical or environmental engineering works. In most cases, for the purpose of simplicity, the problems are studied by considering the suction effects on volume change or shear strength under isothermal conditions. Under isothermal condition, very often, a temperature independent water retention curve is considered in the analysis, which is obviously a simplification. When the temperature changes are too significant to be neglected, it is necessary to account for the thermal effects. In this paper, a method for controlling suction using the vapour equilibrium technique at different temperatures is presented. First, calibration of various saturated saline solutions was carried out from temperature of 20 degrees C to 60 degrees C. A mirror psychrometer was used for the measurement of relative humidity generated by saturated saline solutions at different temperatures. The results obtained are in good agreement with the data from the literature. This information was then used to determine the water retention properties of MX80 clay, which showed that the retention curve is shifting down with increasing of temperature

Geometry-based localization for GPS outage in vehicular cyber physical systems

Vehicular localization has witnessed significant attention due to the growing number of location-based services in vehicular cyber physical systems (VCPS). In vehicular localization, GPS outage is a challenging issue considering the growing urbanization including high rise buildings, multilevel flyovers and bridges. GPS-free and GPS-assisted cooperative localization techniques have been suggested in the literature for GPS outage. Due to the cost of infrastructure in GPS-free techniques, and the absence of location aware neighbors in cooperative techniques, efficient and scalable localization is a challenging task in VCPS. In this context, this paper proposes a geometry-based localization for GPS outage in VCPS (GeoLV). It is a GPS-assisted localization which reduces location-aware neighbor constraint of cooperative localization. GeoLV utilizes mathematical geometry to estimate vehicle location focusing on vehicular dynamics and road trajectory. The static and dynamic relocations are performed to reduce the impact of GPS outage on location-based services. A case study based comparative performance evaluation has been carried out to assess the efficiency and scalability of GeoLV. It is evident from the results that GeoLV handles both shorter and longer GPS outage problem better than the state-of-the-art techniques in VCPS