Airy gas model: From three to reduced dimensions

By using the propagator of linear potential as a main tool, we extend the Airy gas model, originally developed for the three-dimensional ($d=3$) edge electron gas, to systems in reduced dimensions ($d=2,1$). First, we derive explicit expressions for the edge particle density and the corresponding kinetic energy density (KED) of the Airy gas model in all dimensions. The densities are shown to obey the local virial theorem. We obtain a functional relationship between the positive KED and the particle density and its gradients and analyze the results inside the bulk as a limit of the local-density approximation. We show that in this limit the KED functional reduces to that of the Thomas-Fermi model in $d$ dimensions

Ultraslow light propagation in an inhomogeneously broadened rare-earth ion-doped crystal

We show that Coherent Population Oscillations effect allows to burn a narrow spectral hole (26Hz) within the homogeneous absorption line of the optical transition of an Erbium ion-doped crystal. The large dispersion of the index of refraction associated with this hole permits to achieve a group velocity as low as 2.7m/s with a ransmission of 40%. We especially benefit from the inhomogeneous absorption broadening of the ions to tune both the transmission coefficient, from 40% to 90%, and the light group velocity from 2.7m/s to 100m/s

Investigation of radiological diagnostic reference levels in the University Hospital Center Hassan II, Fez

The increasing use of ionizing radiation in the medical field, in Morocco, imposes the issues of the quality of radiological practices and standards for radiation protection especially for patients and manipulator. The present work is part of improving these practices. It constitutes one of the first steps in the process of setting up the diagnostic references levels (DRLs). This concept is considered as an optimization tool for the medical practices concerning the X-ray. This study has been devoted to the determination of diagnostic reference levels, relating to 10 examination types of medical imaging (at the university hospital center Hassan II).After the data collection, the DRL corresponding, have been raised, according to the method known as of 75th percentile. The analysis of the results and their comparison with literature data, allowed making a preliminary assessment of the quality of medical practices, in terms of radiation protection of patients, in the services concerned and outing with some recommendations and perspectives

Scalable multimode entanglement based on efficient squeezing of propagation eigenmodes

Continuous-variable encoding of quantum information in the optical domain has recently yielded large temporal and spectral entangled states instrumental for quantum computing and quantum communication. We introduce a protocol for the generation of spatial multipartite entanglement based on phase-matching of a propagation eigenmode in a monolithic photonic device: the array of quadratic nonlinear waveguides. We theoretically demonstrate in the spontaneous parametric downconversion regime the generation of large multipartite entangled states useful for multimode quantum networks. Our protocol is remarkably simple and robust as it does not rely on specific values of coupling, nonlinearity or length of the sample.Comment: 8 pages, 5 figures, title modified and new results added. Accepted for publication in Physical Review Researc

Use of Continuous Aeration Respirometry Method for the Prediction of Slightly Saline Waste Water Biodegradation

AbstractThe microorganisms growth kinetics is determined by the physical and chemical characteristics of the environment in which they find themselves and multiply; It is therefore essential to understand the effect of these environmental factors to master cell multiplication and hence the pollution biodegradation. Respirometry has been used in recent years in the laboratory as an assessment technique of microbial activity and an effect detector of the contamination (presence of toxic, stress, increase or decrease in pH, temperature variation .) on bacterial respiration and hence on the biological waste water treatment plant. In this study respirometry has been used as a relatively quick and efficient means to detect the effect of the presence of a salt of up to 5g/l (low salt stress) on the degradation of carbon and nitrogen pollution and on bacterial floc aggregation

Risk factors caused by scorpion stings and envenomations in the province of Kelâa Des Sraghna (Morocco)

The present study aims to elucidate the risk factors involved in deaths caused by scorpion envenomation. A retrospective study was carried out in the province of Kelâa des Sraghna from 2003 to 2004. The hospital charts of scorpion envenomation cases treated in the Essalama Hospital in Kelâa des Sraghna were exhaustively analyzed. Our study contains 31 cases of death among 470 hospitalization cases. Most stings had occurred during the hot period peaking in July and August (54.6%). Moreover, the scorpion stings occurred at night in 60.1% of the cases, between 6:00 pm and 6:00 am. In addition, all age groups were affected by envenomation, with a higher frequency in children aged less than 15 years (68.3%). The envenomation rate (class II + class III) was 70.9%. The statistical analysis of the data shows that being less than 15 years old, having been stung during the night and belonging to class III are risk factors that aggravate vital prognosis of hospitalized patients. Furthermore, clinical severity factors, elicited by relative risk analysis, are cardiovascular, respiratory and neurological vital distresses, with relative risks of 14.84, 11.92 and 48.33, respectively. The results of our study clearly displayed the severity and extent of the scorpion envenomation problem. Thus, great attention must be paid to this region of Morocco by the national health authorities

Sorption Study of a Basic Dye “Gentian Violet” from Aqueous Solutions Using Activated Bentonite

AbstractVarious industries like textiles, papers, food, plastics, leather, etc are great water and organic colorant users. Hence, the resulting effluents could be an important source of environmental problems, since they may contain stable and non biodegradable contaminants, like organic dyes. The treatment of which is the main scope of the present study. Different ways of dye removal from these effluents do exist, such as flotation, reverse osmosis, chemical flocculation and adsorption etc. Adsorption is used in this work for the removal of a particular basic dye, known as Gentian violet (GV) from an aqueous solution, by means of a natural clay material. The influence of various key parameters like contact time, temperature, ionic strength, etc. on the adsorbed amount of the dye was investigated, for batch conditions. A kinetic study was also carried out, the obtained experimental results were tested against the pseudo first order and the pseudo second order equations. An analysis of the obtained equilibrium data showed that the dye adsorption is best described by the Langmuir model. The obtained results showed that temperature did enhance the Gentian violet dye retention process onto the considered bentonite whereas the obtained thermodynamic parameters indicated that the adsorption process is spontaneous and endothermic. The simultaneous presence of methylene blue, which is another colorant compound, with the Gentian violet was also considered. The clay materials showed a better affinity for the first one i e. methylene blue. In conclusion and according to the obtained results, the clay material may be recommended as an industrial adsorbent for the treatment of effluents containing Gentian violet (GV)

Thermal Performance of Hybrid PVT Collector with Natural Circulation

Hybrid photovoltaic thermal (PVT) collectors allow simultaneous production of electrical energy thus heat energy. There are several configurations of hybrid collectors (to produce water or air). For hybrids water collectors, there are several configurations that differ by the nature of the absorber (serpentine, tubes...). In this paper, an absorber tank is studied. The circulation of the coolant is natural (we do not use the pump). We present the obtained results in our experimental study and we analyzed the data, and then we compare the results with the theory practices. The electrical performances of the hybrid collector are compared with those of conventional photovoltaic module mounted on the same structure and measured under the same conditions. We conducted experiments with natural circulation of the coolant (Thermosyphon), for a flow rate of 0.025kg/m²

Reversibility of continuous-variable quantum cloning

We analyze a reversibility of optimal Gaussian $1\to 2$ quantum cloning of a coherent state using only local operations on the clones and classical communication between them and propose a feasible experimental test of this feature. Performing Bell-type homodyne measurement on one clone and anti-clone, an arbitrary unknown input state (not only a coherent state) can be restored in the other clone by applying appropriate local unitary displacement operation. We generalize this concept to a partial LOCC reversal of the cloning and we show that this procedure converts the symmetric cloner to an asymmetric cloner. Further, we discuss a distributed LOCC reversal in optimal $1\to M$ Gaussian cloning of coherent states which transforms it to optimal $1\to M'$ cloning for $M'<M$. Assuming the quantum cloning as a possible eavesdropping attack on quantum communication link, the reversibility can be utilized to improve the security of the link even after the attack.Comment: 7 pages, 5 figure