Fine structure of the (A0 X) complex in InP

We present stress-dependent photoluminescence measurements on exciton bound to neutral acceptor in InP. We analyse the experimental results in two theoretical schemes : the j-j coupling scheme and the crystal field scheme. We find that the triplet structure of the (A0 X) complex results from hole-hole coupling in the cubic crystal field. We show that the three bound-exciton states correspond to Γ8, Γ7,8, Γ 6 in order of increasing energies, the electron-hole exchange energy being found to be vanishingly small

Fine structure of the (A0 X) complex in InP

We present stress-dependent photoluminescence measurements on exciton bound to neutral acceptor in InP. We analyse the experimental results in two theoretical schemes : the j-j coupling scheme and the crystal field scheme. We find that the triplet structure of the (A0 X) complex results from hole-hole coupling in the cubic crystal field. We show that the three bound-exciton states correspond to Γ8, Γ7,8, Γ 6 in order of increasing energies, the electron-hole exchange energy being found to be vanishingly small.Nous présentons des mesures de photoluminescence sous contrainte uniaxiale associées à l'exciton lié à un accepteur neutre dans InP. Les résultats sont analysés suivant deux schémas théoriques : le schéma de couplage j-j et le schéma du champ cristallin. Nous montrons que la structure fine du complexe (A0 X) résulte du couplage des deux trous dans le champ cristallin cubique. Les trois états qui en résultent sont respectivement Γ 8, Γ7,8, Γ6 dans l'ordre des énergies croissantes, l'énergie d'échange électron-trou étant négligeable

Percutaneous treatment of abdominal fluid collections (about 33 cases)

Les auteurs rapportent une série de 33 cas de collections abdominales colligées au service des urgences chirurgicales viscérales du CHU Ibn Sina de Rabat, sur une période de 4 ans. L'âge moyen des patients est de 42 ans. La majeure partie de ces abcès siège au niveau du foie (19 cas). Le traitement percutané est réalisé sous guidage échographique dans tous les cas. Les résultats sont satisfaisants avec 78.7 % de succès. Sept malades ont nécessité un abord chirurgical. Ces données sont conformes avec celles retrouvées dans la littérature. Les auteurs rappellent les multiples intéréts de ce traitement, mais aussi les complications possibles

Movements in Ethiopia, Ethiopia in Movement. Volume 1

In November 2012, the 18th International Conference of Ethiopian Studies was convened in Dire Dawa, a cosmopolitan city in the eastern lowlands of Ethiopia. This event gathered more than 300 international scholars from all disciplines of the humanities and social social sciences. Under the general theme of ‘movement’ these two volumes gather a collection of 70 papers that reflect recent trends in the field of Ethiopian studies. From local studies to regional and international perspectives, these studies question long term historical processes and current social and economic transformations. A number of contributions explore and give access to fresh sources of knowledge from unpublished or rediscovered texts and documents, from recordings of oral information, or from ethnographic observation. They also review literature, challenge conventional ideas and propose critical investigations on past and present issues, such as interethnic relations, women’s role, development policies and their impact

Alkaliphiles : The Emerging Biological Tools Enhancing Concrete Durability

Concrete is one of the most commonly used building materials ever used. Despite it is a very important and common construction material, concrete is very sensitive to crack formation and requires repair. A variety of chemical-based techniques and materials have been developed to repair concrete cracks. Although the use of these chemical-based repair systems are the best commercially available choices, there have also been concerns related to their use. These repair agents suffer from inefficiency and unsustainability. Most of the products are expensive and susceptible to degradation, exhibit poor bonding to the cracked concrete surfaces, and are characterized by different physical properties such as thermal expansion coefficients which are different to that of concrete. Moreover, many of these repair agents contain chemicals that pose environmental and health hazards. Thus, there has been interest in developing concrete crack repair agents that are efficient, long lasting, safe, and benign to the environment and exhibit physical properties which resemble that of the concrete. The search initiated by these desires brought the use of biomineralization processes as tools in mending concrete cracks. Among biomineralization processes, microbially initiated calcite precipitation has emerged as an interesting alternative to the existing chemical-based concrete crack repairing system. Indeed, results of several studies on the use of microbial-based concrete repair agents revealed the remarkable potential of this approach in the fight against concrete deterioration. In addition to repairing existing concrete cracks, microorganisms have also been considered to make protective surface coating (biodeposition) on concrete structures and in making self-healing concrete. Even though a wide variety of microorganisms can precipitate calcite, the nature of concrete determines their applicability. One of the important factors that determine the applicability of microbes in concrete is pH. Concrete is highly alkaline in nature, and hence the microbes envisioned for this application are alkaliphilic or alkali-tolerant. This work reviews the available information on applications of microbes in concrete: repairing existing cracks, biodeposition, and self-healing. Moreover, an effort is made to discuss biomineralization processes that are relevant to extend the durability of concrete structures