Z_q(Z_q+uZ_q)-Linear Skew Constacyclic Codes

In this paper, we study skew constacyclic codes over the ring $\mathbb{Z}_{q}R$ where $R=\mathbb{Z}_{q}+u\mathbb{Z}_{q}$, $q=p^{s}$ for a prime $p$ and $u^{2}=0.$ We give the definition of these codes as subsets of the ring $\mathbb{Z}_{q}^{\alpha}R^{\beta}$. Some structural properties of the skew polynomial ring $R[x,\Theta]$ are discussed, where $\Theta$ is an automorphism of $R.$ We describe the generator polynomials of skew constacyclic codes over $\mathbb{Z}_{q}R,$ also we determine their minimal spanning sets and their sizes. Further, by using the Gray images of skew constacyclic codes over $\mathbb{Z}_{q}R$ we obtained some new linear codes over $\mathbb{Z}_{4}$. Finally, we have generalized these codes to double skew constacyclic codes over $\mathbb{Z}_{q}R$

Effect of water deficit stress on physiological traits of some Algerian barley genotypes

Recently, drought stress became more frequent and this presents a serious challenge for plant breeders to create tolerant barley genotypes with good stability under water deficit conditions. The present study aims to evaluate the effects of water deficit stress with 20% of maximum soil water capacity at heading stage on the physiological traits of some barley genotypes and to set recommendations on their possible use in drought tolerance breeding programs. The results revealed significant differences between genotypes in all tested traits. In this regard, Rahma and Tissa maintained a high relative water content and cell membrane stability under water deficit stress, respectively. These characteristics present effective mechanisms to face drought stress in semi-arid regions. Jaidor was the most stay-green genotype characterized by maintaining a high level of chlorophyll content after water deficit stress treatment. Moreover, Acsad176 accumulated high soluble sugars content as a response to water deficit stress. These genotypes could be considered as potential sources of genes for selection of drought tolerant barley varieties

Arbitration-Induced Preemption Delays

The interactions among concurrent tasks pose a challenge in the design of real-time multi-core systems, where blocking delays that tasks may experience while accessing shared memory have to be taken into consideration. Various memory arbitration schemes have been devised that address these issues, by providing trade-offs between predictability, average-case performance, and analyzability. Time-Division Multiplexing (TDM) is a well-known arbitration scheme due to its simplicity and analyzability. However, it suffers from low resource utilization due to its non-work-conserving nature. We proposed in our recent work dynamic schemes based on TDM, showing work-conserving behavior in practice, while retaining the guarantees of TDM. These approaches have only been evaluated in a restricted setting. Their applicability in a preemptive setting appears problematic, since they may induce long memory blocking times depending on execution history. These blocking delays may induce significant jitter and consequently increase the tasks\u27 response times. This work explores means to manage and, finally, bound these blocking delays. Three different schemes are explored and compared with regard to their analyzability, impact on response-time analysis, implementation complexity, and runtime behavior. Experiments show that the various approaches behave virtually identically at runtime. This allows to retain the approach combining low implementation complexity with analyzability

APPLICATION OF 2D SURFACE ELECTRICAL RESISTIVITY TOMOGRAPHY TO DETECT THE UNDERGROUND CAVITIES A CASE SITE STUDY: TOLGA AREA (ALGERIA)

Electrical resistivity tomography method is considered among the best non-destructive and non invasive geophysical techniques for detecting and characterizing the underground cavities and associated disorders. The detection of cavities in urban areas is important to prevent against different causes of accidents related to possible collapse and subsidence. This study focused on the application of electrical resistivity measurements to locate and identify cavities in the soil. The survey site is located in Biskra City, south-east of Algeria. This field contains cavities of natural origin and different sizes. The procedure using the electrical resistivity tomography of Wenner array permitted to detect the cavities in the range of depth 2 to 4m. These cavities were caused by the dissolution phenomena of carbonate materials. Also mechanical and dynamic penetrometer tests were performed in order to propose a solution for foundations building

Ab initio study of the beta$-tin->Imma->sh phase transitions in silicon and germanium

We have investigated the structural sequence of the high-pressure phases of silicon and germanium. We have focussed on the cd->beta-tin->Imma->sh phase transitions. We have used the plane-wave pseudopotential approach to the density-functional theory implemented within the Vienna ab-initio simulation package (VASP). We have determined the equilibrium properties of each structure and the values of the critical parameters including a hysteresis effect at the phase transitions. The order of the phase transitions has been obtained alternatively from the pressure dependence of the enthalpy and of the internal structure parameters. The commonly used tangent construction is shown to be very unreliable. Our calculations identify a first-order phase transition from the cd to the beta-tin and from the Imma to the sh phase, and they indicate the possibility of a second-order phase-transition from the beta-tin to the Imma phase. Finally, we have derived the enthalpy barriers between the phases.Comment: 12 pages, 16 figure

Elastic and electronic properties of hexagonal rhenium sub-nitrides Re3N and Re2N in comparison with hcp-Re and wurtzite-like rhenium mononitride ReN

Very recently, two new hexagonal rhenium sub-nitrides Re3N and Re2N, which belong to a rather rare group of known metal-rich (M/N > 1) nitrides of heavy 4d,5d metals, have been successfully synthesized, and their potential technological applications as ultra-incompressible materials have been proposed. In this work we present a detailed ab initio study of novel rhenium sub-nitrides in comparison with hcp-Re and wurtzite-like rhenium mono-nitride ReN, with the purpose to evaluate the trends of the elastic, electronic properties and chemical bonding in the series of these hexagonal systems as a function of the Re/N stoichiometry: Re \rightarrow Re3N \rightarrow Re2N \rightarrow ReN.Comment: 12 pages, 2 figure

Contribution à la reconnaissance du sol par tomographie électrique

Les méthodes électriques par courant continu en géophysique, ont pour objectif de déterminer les propriétés électriques du sol par la mesure de sa résistivité. La technique de tomographie électrique est la reconnaissance multi-dimensionnelle des propriétés électriques intrinsèques du milieu étudié. En géophysique, cette technique permet de traduire les données acquises en surface ou en sub-surface en une image interprétable en termes géologique. La tomographie électrique est fréquemment employée dans différents domaines (géologie, hydrogéologie, génie civil et environnement, etc.). Notre travail est basé sur l'utilisation de la méthode dite: la résistivité de tomographie électrique selon l’acquisition 2D. D’une part, pour tester la capacité de la méthode de tomographie électrique, afin de localiser et de déterminer les cavités souterraines dans le proche sous-sol et la caractérisation du sol par des mesures in situ, et d’autre part pour faire des comparaisons par simulation numérique. En utilisant les logiciels Res2Dmod et Res2Dinv, pour différents dispositifs d’électrodes de mesure utilisés en tomographie électrique (Wenner, Dipôle-dipôle, Pôle-dipôle, Pôle-pôle, Schlumberger et Gradient). Les cavités modélisées ont des sections circulaires et rectangulaires avec différentes résistivités du milieu encaissant, ainsi que d’évaluer le comportement de ces dispositifs d’électrodes et déduire leurs avantages et leurs inconvénients. L'étude a conclu que cette technique de tomographie électrique est efficace et a montré son efficacité pour la reconnaissance du sol. Les résultats de la modélisation numérique, ont montré que le dispositif d’électrode dipôle-dipôle a donné de bons résultats pour la détection des cavités souterraines dans le proche sous-sol, en l'absence de bruit. Mais, en présence de bruit, les dispositifs d’électrodes: gradient, pôle-pôle et pôle dipôle ont donné de bons résultats