853 research outputs found

    Évolution de la température de l’air et des précipitations dans la région côtière syrienne (gouvernorat de Lattaquié) de 1970 à 2016

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    This study aims to analyze the changes in the annual and seasonal averages of air temperature and precipitation over Lattakia Governorate during the period 1970-2016. Annual and seasonal trends for temperature and precipitation were calculated by using the non-parametric Mann-Kendall test. The mean differences between the two periods 1970-2000 and 2001-2016, were assessed at the annual and seasonal scales by using the non-parametric Mann-Whitney U test. Furthermore, the occurrence of extreme high/low values were analyzed at the annual scale by using the normal distribution curve. The study found that the annual temperature averages significantly (p<0.05) increased by 0.22 ˚C/decade and 0.17 ˚C/decade, respectively at Lattakia and Hiffeh stations during the period 1970-2016. Summer exhibited strong and significant (at level 0.01) increasing trends by 0.39 ˚C/decade at Lattakia, and by 0.34 ˚C/decade at Hiffeh. Total spring precipitation significantly decreased by -6.5 mm/decade at Lattakia and by -12.1 mm/decade at Hiffeh. Probability of the occurrence of the value 20.2 ˚C or more as an extreme value increased by 40.8% at Lattakia station during the period 2001-2016. Este estudio tiene como objetivo analizar los cambios en los promedios anuales y estacionales de la temperatura del aire y las precipitaciones en la gobernación de Lattakia durante 1970-2016. Las tendencias anuales y estacionales para la temperatura y la precipitación se calcularon utilizando la prueba no paramétrica de Mann-Kendall. Las diferencias de medias entre los dos períodos (1970-2000) / (2001-2016) se evaluaron en los niveles anuales y estacionales mediante el uso de la prueba no paramétrica de Mann-Whitney U. Además, la aparición de valores extremadamente altos / bajos se analizó a nivel anual mediante el uso de la curva de distribución normal. El estudio encontró que los promedios anuales de temperatura aumentaron significativamente (p <0.05) en 0.22 ˚C / década y 0.17 ˚C \ década, en las estaciones de Lattakia y Hiffeh, respectivamente, durante 1970-2016. El verano reveló tendencias fuertes y significativas al alza (a nivel 0.01) en sus promedios de temperatura en 0.39 ˚C / década en Lattakia, y en 0.34 ˚C / década en Hiffeh. El promedio de precipitaciones de primavera disminuyó significativamente en -6.5 mm / década en Lattakia y en -12.1 mm / década en Hiffeh. La probabilidad de la aparición del valor de 20.2 ˚C o más como valor extremo aumentó en la estación de Lattakia durante 2001-2016 en un 40.8%.L’objectif de cette étude est d’analyser les changements dans les moyennes annuelles et saisonnières de la température de l’air et des précipitations sur la région du gouvernorat de Lattaquié entre 1970 et 2016. Les tendances annuelles et saisonnières de la température ont été calculées à l’aide du test non-paramétrique de Mann-Kendall. Les différences moyennes entre les périodes 1970-2000 et 2001-2016 ont été évaluées par année et saison en utilisant le test non-paramétrique de Mann-Whitney U. En ce qui concerne l’occurence de valeurs extrêmement élevées/ basses, celle-ci a été analysée sur une base annuelle en utilisant la courbe de distribution normale. L’étude a révélé que les températures moyennes annuelles (p<0,05) ont augmenté significativement de 0,22 ˚C / décennie et de 0,17 ˚C / décennie, dans les cas respectifs des stations de Lattakia et de Haffah durant la période 1970-2016. L’été a laissé voir une tendance marquée à la hausse (au niveau de 0,01) de ses moyennes de température : 0,39 ˚C / décennie à Lattaquié et 0,34 ˚C / décennie à Hiffeh. La moyenne des précipitations printanières a diminué de manière significative, soit de -6,5 mm / décennie à Lattakia et de -12,1 mm / décennie à Hiffeh. La probabilité d’apparition de la valeur de 20,2 ˚C ou plus comme valeur extrême a augmenté de 40,8% pour la station de Lattaquié pendant la période 2001-2016

    Lung protection in cardio-pulmonary bypass

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    Since the invention of the heart-lung machine paediatric cardiac surgery developed rapidly. For correction of complex cardiac malformations the application of a cardio-pulmonary bypass (CPB) has become indispensable but possible negative effects of this technique should not be neglected. Especially, both bypassed organs i.e. heart and lung are not perfused during the procedure and therefore are threatened by ischemia and reperfusion injury. Additionally, CPB was developed with a non-pulsatile flow but there are clinical observations that pulsatile flow might be superior with improved patient outcomes. Thus, the aim of our study was to evaluate the effect of CPB on lung structure and to assess whether different flow modalities (pulsatile vs. non-pulsatile flow) or application of the antibiotic minocycline might be advantageous. Thirty five piglets of four weeks age were examined and divided into five experimental groups: control (no CPB) without or with minocycline, CPB (non-pulsatile flow) without or with minocycline and CPB with pulsatile flow. CPB was performed for 90 min followed by a 120 min reperfusion and recovery phase. Thereafter, adenosine triphosphate-content of lung biopsies and histology was carried out. We found that CPB was associated with a significant thickening of alveolar wall accompanied by an infiltration of neutrophil leucocytes. Moreover, markers for hypoxia, apoptosis, nitrosative stress, inflammation and DNA damage were significantly elevated after CPB. These cellular damages could be partially inhibited by minocycline or pulsatile flow. Both, minocycline and pulsatile flow attenuate lung damage after CPB

    Dynamic resource allocation for opportunistic software-defined IoT networks: stochastic optimization framework

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    Several wireless technologies have recently emerged to enable efficient and scalable internet-of-things (IoT) networking. Cognitive radio (CR) technology, enabled by software-defined radios, is considered one of the main IoT-enabling technologies that can provide opportunistic wireless access to a large number of connected IoT devices. An important challenge in this domain is how to dynamically enable IoT transmissions while achieving efficient spectrum usage with a minimum total power consumption under interference and traffic demand uncertainty. Toward this end, we propose a dynamic bandwidth/channel/power allocation algorithm that aims at maximizing the overall network’s throughput while selecting the set of power resulting in the minimum total transmission power. This problem can be formulated as a two-stage binary linear stochastic programming. Because the interference over different channels is a continuous random variable and noting that the interference statistics are highly correlated, a suboptimal sampling solution is proposed. Our proposed algorithm is an adaptive algorithm that is to be periodically conducted over time to consider the changes of the channel and interference conditions. Numerical results indicate that our proposed algorithm significantly increases the number of simultaneous IoT transmissions compared to a typical algorithm, and hence, the achieved throughput is improved

    Domain walls at the spin density wave endpoint of the organic superconductor (TMTSF)2PF6 under pressure

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    We report the first comprehensive investigation of the organic superconductor (TMTSF)2PF6 in the vicinity of the endpoint of the spin density wave - metal phase transition where phase coexistence occurs. At low temperature, the transition of metallic domains towards superconductivity is used to reveal the various textures. In particular, we demonstrate experimentally the existence of 1D and 2D metallic domains with a cross-over from a filamentary superconductivity mostly along the c?-axis to a 2D superconductivity in the b?c-plane perpendicular to the most conducting direction. The formation of these domain walls may be related to the proposal of a soliton phase in the vicinity of the critical pressure of the (TMTSF)2PF6 phase diagram.Comment: 5 page

    Insertion Detection System Employing Neural Network MLP and Detection Trees Using Different Techniques

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    by addressing intruder attacks, network security experts work to maintain services available at all times. The Intrusion Detection System (IDS) is one of the available mechanisms for detecting and classifying any abnormal behavior. As a result, the IDS must always be up to date with the most recent intruder attack signatures to maintain the confidentiality, integrity, and availability of the services. This paper shows how the NSL-KDD dataset may be used to test and evaluate various Machine Learning techniques. It focuses mostly on the NLS-KDD pre-processing step to create an acceptable and balanced experimental data set to improve accuracy and minimize false positives. For this study, the approaches J48 and MLP were employed. The Decision Trees classifier has been demonstrated to have the highest accuracy rate for detecting and categorizing all NSL-KDD dataset attacks

    Revisiting the anatomy of the cephalic vein, its origin, course and possible clinical correlations in relation to the anatomical snuffbox among Jordanian

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    Background: The cephalic vein is one of the most distinguished superficial veins of the upper limb. Its clinical value lies in venous access. There is little known about the variation of its formation in relation to the anatomical snuffbox. Hence, anatomical variants in the origin of the cephalic vein are important in clinical practice. Subsequently, this study was designed to examine the variation of the cephalic vein formation in relation to the anatomical snuffbox. Materials and methods: A cross-sectional study of 438 subjects (722 hands), was prepared to study the cephalic vein among Jordanian students and staff of one of the major governmental Medical College in Jordan, by using infrared illumination system. The obtained data was analysed according to; gender, sidedness, and handedness. Results: Four sites for the formation of the cephalic vein in relation to the anatomical snuffbox were found. There was a significant relation between gender and sidedness, and the sites of formation of the cephalic vein (p < 0.0001 and p = 0.048, respectively). Conclusions: For the first time this study identified different sites for the formation of the cephalic vein in relation to the anatomical snuffbox. However, regardless of its sites of formation, the cephalic vein was running in 98% of the examined hands in the anatomical snuffbox

    Cloud Computing Based Computing System for Women's Higher Education in Isolated Areas

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    A new chapter in information technology is opened by cloud computing in computer science and engineering education. Understanding the importance of using cloud computing (CC) in institutions of higher learning is the aim of this research. This analysis shows some of the benefits that cloud computing can provide to higher education, assesses some of the most significant challenges that academics may encounter as a result of its implementation, and suggests some initial steps toward its adoption while mitigating the risks associated. Enterprise apps have migrated in large numbers to the cloud in recent years. One of the challenges posed by cloud applications is the challenge of allocating resources to the application to ensure a service level along dimensions like performance, availability, and dependability. To do this, a system based on the infrastructure of governmental bodies, non-governmental organisations (NGOs), academic institutions, and other providers of social services has been established. The results of this analysis demonstrate that it is possible to use a few variables, including administrative bodies and governments, internal stakeholders, cloud suppliers, firm attributes, socio-political changes, IT framework, and others, to understand how CC adoption methodologies are used in higher education institutions. In addition to providing insight into how cloud providers, advisers, governments, and academics see various market demands and how they respond to these expectations while expanding services provided by CC in higher education institutions, this analysis opens opportunities for future research. The implications for practice can aid decision-makers in utilizing CC services legally

    Spatio-temporal analysis of maximum and minimum temperatures over Levant region (1987-2017)

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    Ponencia presentada en: XI Congreso de la Asociación Española de Climatología celebrado en Cartagena entre el 17 y el 19 de octubre de 2018.[ES]El objetivo de este estudio es analizar los cambios espaciales y temporales en los promedios anuales y estacionales de las temperaturas máxima y mínima en la región del Levante durante 1987-2017. Estos promedios se calcularon a partir de datos diarios para cada estación y para toda la región de Levante. Las tendencias espaciales y temporales para tres variables se calcularon utilizando la prueba no paramétrica de Mann-Kendall. Además, la diferencia de medias anuales y estacionales entre los dos períodos 1987-2000 y 2001-2011 se evaluó mediante el uso de la prueba U no paramétrica de Mann-Whitney. Durante 1987-2017, la región de Levante fue testigo de un calentamiento significativo en las temperaturas máximas y mínimas anuales de 0.33 y 0.30ºC/década, respectivamente. Además, la primavera mostró una tendencia al calentamiento muy fuerte y significativa en comparación con otras estaciones en 0.53ºC/década para la temperatura máxima y en 0.51ºC/década para la temperatura mínima. La temperatura máxima y mínima anual, de primavera y verano han aumentado significativamente en esta región durante 2001-2017 en comparación con el período 1987-2000. Las tendencias decrecientes mostraron un patrón muy aislado y aleatorio en comparación con las tendencias de calentamiento amplias, intensivas y coherentes en los promedios anuales y estacionales de la temperatura máxima y mínima. Las tasas de calentamiento en Jordania fueron generalmente las más altas.[EN]This study aims to analyze the spatial and temporal variability of the annual and seasonal maximum (Tmax) and minimum (Tmin) temperatures, along with the diurnal temperature range (DTR) over the entire Levant region for the period 1987-2017. The temporal trends for these three variables were calculated at the annual and seasonal scales by using the non-parametric Mann-Kendall test. Furthermore, the difference of the means between the two periods (1987-2000 and 2001-2017) were assessed by using the non-parametric Mann-Whitney U test. During 1987-2017, the Levant region suffered a significant warming for the annual maximum and minimum temperatures around 0.33 and 0.30ºC\decade, respectively. In addition, spring showed very strong and significant warming trend (around 0.53ºC/decade for Tmax and 0.51ºC/decade for Tmin) compared with the other seasons. The annual, spring and summer means of Tmax and Tmin have significantly increased over the Levant region during 2001-2017 compared with the period 1987-2000. Spatially, the decreasing trends showed very isolated and random patterns compared with the broad, intensive and coherent warming trends at annual and seasonal time scales. The warming over Jordan was generally the highest.This work has been financed by the projects P11-RNM-7941 (Junta de Andalucía), CGL2013-48539-R (MINECO-Spain, FEDER) and CGL2017-89836-R (MINECO-Spain, FEDER)

    An Optimal Routing Protocol Using a Multiverse Optimizer Algorithm for Wireless Mesh Network

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    Wireless networks, particularly Wireless Mesh Networks (WMNs), are undergoing a significant change as a result of wireless technology advancements and the Internet's rapid expansion. Mesh routers, which have limited mobility and serve as the foundation of WMN, are made up of mesh clients and form the core of WMNs. Mesh clients can with mesh routers to create a client mesh network. Mesh clients can be either stationary or mobile. To properly utilise the network resources of WMNs, a topology must be designed that provides the best client coverage and network connectivity. Finding the ideal answer to the WMN mesh router placement dilemma will resolve this issue MRP-WMN. Since the MRP-WMN is known to be NP-hard, approximation methods are frequently used to solve it. This is another reason we are carrying out this task. Using the Multi-Verse Optimizer algorithm, we provide a quick technique for resolving the MRP-WMN (MVO). It is also proposed to create a new objective function for the MRP-WMN that accounts for the connected client ratio and connected router ratio, two crucial performance indicators. The connected client ratio rises by an average of 16.1%, 12.5%, and 6.9% according to experiment data, when the MVO method is employed to solve the MRP-WMN problem, the path loss falls by 1.3, 0.9, and 0.6 dB when compared to the Particle Swarm Optimization (PSO) and Whale Optimization Algorithm (WOA), correspondingly
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