The Impact of Information and Communication Technologies on International Trade: The Case of MENA Countries

Given the importance of international trade, we empirically investigate the impact of information and communication technologies on the exports, imports, and total trade of five service items by using a panel data for 19 MENA countries from 2005 to 2019. Unlike most previous studies, we use the Information and Communication Technologies Development Index, which is a composite index that combines 11 indicators that include the access, use, and skill aspects of the technology. The results are as follows: the Information and Communication Technologies Development Index has a negative and statistically significant effect on exports of information technology services, and a positive and statistically significant effect on imports and total trade in financial services. Furthermore, we found also that the Information and Communication Technologies access sub-index has a significant effect on total trade in information technology services and transport. For the Information and Communication Technologies use sub-index, its effect on imports of travel services and exports of both travel and information technology services is significant. It also has a significant positive effect on total trade in travel and information technology services. As for the Information and Communication Technologies skills sub-index, the results show that it has significant positive effects on total trade in IT services and travel, and a negative significant effect on transport. These results provide interesting policy insights for information and communication technologies development and the growth of services trade for policy makers

Analyse spectroscopique des plasmas en présence d'un champ magnétique (application au plasma de bord des tokamaks)

Après avoir posé le formalisme de base nécessaire pour la modélisation des profils de raies, ce travail examine l'effet Zeeman dans le cas général d'un émetteur arbitraire. Un modèle qui retient simultanément l'effet Stark et l'effet Zeeman est ensuite proposé, et appliqué, à plusieurs émetteurs dans les plasmas. Nous avons étudié par exemple les profils des raies d'émission Da et D[delta] du deutérium, et de la raie 9-4 de He+, en prenant en compte les effets Doppler, Zeeman et Stark. Une étude a été menée sur un spectre du carbone neutre afin de caractériser la température des atomes au bord du plasma. Les spectres sont observés dans le visible par une visée parallèle à un neutraliseur du divertor ergodique du Tokamak Tore supra. Une analyse de l'importance relative de ces effets a été faite dans les conditions de densité (10[19] < Ne <10[20] m[-3]) et de température (10 < Te < 50 eV) que l'on rencontre dans les plasmas de bord du Tokamak Tore-Supra. Nous montrons que pour certaines conditions de plasma, la largeur de ces raies dépend à la fois de la température de l'émetteur, du microchamp électrique local du plasma, et du champ magnétique.AIX-MARSEILLE1-BU Sci.St Charles (130552104) / SudocSudocFranceF

Contribution of Lienard-Wiechert Potential to the Electron Broadening of Spectral Lines in Plasmas

Lienard-Wiechert or retarded electric and magnetic fields are produced by moving electric charges with respect to a rest frame. In hot plasmas, such fields may be created by high velocity free electrons. The resulting electric field has a relativistic expression that depends on the ratio of the free electron velocity to the speed of light in vacuum c. In this work, we consider the semi-classical dipole interaction between the emitter ions and the Lienard-Wiechert electric field of the free electrons and compute its contribution to the broadening of the spectral line shape in hot and dense plasmas

Doppler Broadening of Spectral Line Shapes in Relativistic Plasmas

In this work, we report some relativistic effects on the spectral line broadening. In particular, we give a new Doppler broadening in extra hot plasmas that takes into account the possible high velocity of the emitters. This suggests the use of an appropriate distribution of the velocities for the emitters. Indeed, the Juttner-Maxwell distribution of the velocities is more adequate for relativistic velocities of the emitters when the latter are in plasma with an extra high temperature. We find an asymmetry in the Doppler line shapes unlike the case of the traditional Doppler effect