String GUTs

Standard SUSY-GUTs such as those based on $SU(5)$ or $SO(10)$ lead to predictions for the values of $\alpha _s$ and $sin^2\theta _W$ in amazing agreement with experiment. In this article we investigate how these models may be obtained from string theory, thus bringing them into the only known consistent framework for quantum gravity. String models with matter in standard GUT representations require the realization of affine Lie algebras at higher levels. We start by describing some methods to build level $k=2$ orbifold string models with gauge groups $SU(5)$ or $SO(10)$. We present several examples and identify generic features of the type of models constructed. Chiral fields appropriate to break the symmetry down to the standard model generically appear in the massless spectrum. However, unlike in standard SUSY-GUTs, they often behave as string moduli, i.e., they do not have self-couplings. We also discuss briefly the doublet-triplet Higgs splitting. We find that, in some models, built-in sliding-singlet type of couplings exist.Comment: 40 pages, Latex. Two references modified, few other unimportant change

Les femmes pour la paix en République démocratique allemande

Des motifs spécifiques ont permis l’émergence de groupes de « femmes pour la paix » en RDA. Ce texte montre comment ces dernières sont reliées à une nouvelle tendance mondiale : celle de la mobilisation à l’Ouest et à l’Est des femmes qui expriment activement leurs inquiétudes et leurs préoccupations face à la militarisation. Parallèlement la répression s’est accrue des deux côtés de la barrière Est-Ouest contre ces femmes qui cherchent à briser l’image de l’ennemi. Face à ce genre de traitement particulier, les femmes est-allemandes sont devenues plus conscientes des problèmes féministes et en viennent progressivement à l’option du féminisme.Specific factors have played an important part in the growth of a "Women for Peace" movement in East Germany. This article discusses how this movement is related to a new global phenomenon: the concern of women in both East and West about militarization of society. Women who have sought to break down the monolithic stereotype of the enemy have been met with ever greater repression on both sides of the iron curtain. The particular forms this repression has taken has served to reinforce the feminist consciousness of women in East Germany.La emergencia de grupos de "mujeres por la paz" en la República Federal Alemana es el resultado de causas muy específicas. Este texto muestra cómo ellas están ligadas a una nueva tendencia mundial: la de la movilización tanto en el Oeste como en el Este de mujeres que expresan activamente sus inquietudes y su preocupación frente a la militarización. paralelamente, la represión contra estas mujeres que buscan destruir una imagen del enemigo ha aumentado, y por ambos lados de la barrera Este-Oeste. Frente a este tratamiento, las mujeres de la Alemania oriental están más conscientes de los problemas femeninos, y avanzan progresivamente hacia una opción feminista