980 resultados para Structural transition
Resumo:
The recent wave of upheavals and revolts in Northern Africa and the Middle East goes back to an old question often raised by theories of collective action: does repression act as a negative or positive incentive for further mobilization? Through a review of the vast literature devoted to this question, this article aims to go beyond theoretical and methodological dead-ends. The article moves on to non-Western settings in order to better understand, via a macro-sociological and dynamic approach, the causal effects between mobilizations and repression. It pleads for a meso- and micro-level approach to this issue: an approach that puts analytical emphasis both on protest organizations and on individual activists' careers.
Resumo:
This study analyses the stratigraphy, structure and kinematics of the northern part of the Adula nappe of the Central Alps. The Adula nappe is one of the highest basement nappes in the Lower Penninic nappe stack of the Lepontine Dome. This structural position makes possible the investigation of the transition between the Helvetic and North Penninic paleogeographic domains. The Adula nappe is principally composed of crystalline basement rocks. The investigation of the pre-Triassic basement shows that it contains several Palaeozoic detrital metasedimentary formations dated from the Cambrian to the Ordovician. These formations contain also some volcanic or intrusive magmatic rocks. Ordovician metagranites dated at ~450 Ma are also a common rock-type of the Adula basement. These formations underwent Alpine and Variscan deformation and metamorphism. Permian granites (Zervreila orthogneiss, dated at ~290 Ma) have intruded this pre-structured basement in a post-orogenic geodynamic context. Due to their age, the Zervreila orthogneiss are good markers for alpine deformation. The stratigraphy of the Mesozoic and Paleogene sedimentary cover of the Adula nappe is essential to unraveling its pre- orogenic history. The autochthonous cover is assigned to a North Penninic Triassic series that testifies for a transition between the Helvetic and Briançonnais Triassic domains. The Adula domain goes through an emersion during the Middle Jurassic, and is part of a topographic high during the first phase of the Alpine rift. The sediments of the late Middle Jurassic show a drowning phase associated with a tectonic activity and a breccia formation. In the neighbouring domains, coeval with the drowning phase in the Adula domain, a strong extensional crustal delamination and a scattered magmatic activity is associated with the main opening of the North Penninic domain. The Upper Jurassic of the Adula nappe is characterized by a carbonate formation comparable with those in the Helvetic or Subbriaçonnais domains. Flysch s.l. deposition starts probably at the end of the Cretaceous. These sediments are deposited on a large unconformity testifying for a Cretaceous sedimentary gap. The Adula nappe exhibits a very complex structure. This structure is formed by several deformation phases. Two ductile deformations are responsible for the nappe emplacement. The first deformation phase is associated with a folding compatible with a top-to-south movement at the top of the nappe. The second phase is dominant and pervasive throughout the whole nappe. It goes with a strong north vergent folding and the main nappe emplacement. These two phases cause the exhumation and emplacement of a coherent, although pre-structured, piece of continental crust. Two further deformation phases postdate the nappe emplacement. - Ce travail concerne l'étude géologique de la partie nord de la nappe de l'Adula dans les Alpes centrales. La nappe de l'Adula est l'une des nappes cristallines la plus élevée dans la pile des nappes du Pennique inférieur des Alpes lepontines. Cette position particulière permet d'étudier la transition entre les nappes des domaines helvétique et pennique inférieur. La nappe de l'Adula est principalement composée de socle cristallin : l'étude de l'histoire géologique du socle est donc l'un des thèmes de cette recherche. Ce socle contient plusieurs formations métasédimentaires paléozoïques du Cambrien à I'Ordovicien. Ces métasédiments sont issus de formations clastiques comprenant souvent des roches magmatiques volcaniques et intrusives. Ces métasédiments ont subi les cycles orogéniques varisque et alpin. La nappe de l'Adula contient plusieurs corps magmatiques granitiques métamorphisés. Les premiers métagranites sont Ordovicien et témoignent d'un environnement de marge active. Ces granites sont aussi polymétamorphiques. Les deuxièmes métagranites sont représentés par les orthogneiss de type Zervreila. Ce métagranite est d'âge permien (-290 Ma). Il est mis en place dans un contexte tectonique post-orogénique. Ce granite est un maqueur de la déformation alpine car il n'est pas affecté par les orogenèses précédentes, flippy Le contenu stratigraphique des roches mésozoïques et cénozoiques de la couverture sédimentaire de la nappe de l'Adula est'important pour en étudier son histoire pré-alpine. La couverture autochtone est composée d'une série d'âge triasique d'affinité nord-pennique, un faciès qui marque la transition entre les domaines helvétiques et briançonnais au Trias. Le domaine paléogéographique représenté dans la nappe de l'Adula connaît une émersion pendant le Jurassique moyen. Cette émersion marque le commencement du rift dans le domaine alpin. La sédimentation de la fin du Jurassique moyen est marquée par une transgression marine accompagnée par des mouvements tectoniques et la formation d'une brèche. Cette transgression est contemporaine des importants mouvements tectoniques et des manifestations magmatiques dans les unités voisines qui marquent la phase principale d'ouverture du bassin nord-pennique. Le Jurassique supérieur est caractérisé par l'instauration d'une sédimentation carbonatée comparable à celle du domaine helvétique ou subbriançonnais. Une sédimentation flyschoïde, probablement du Crétacé à Tertiaire, est déposée sur une importante discordance qui témoigne d'une lacune au Crétacé. La structure complexe de la nappe de l'Adula témoigne de nombreuses phases de déformation. Ces phases de déformation sont en partie issues de la mise en place de la nappe et de déformations plus tardives. La mise en place de la nappe produit deux phases de déformation ductile : la première produit un plissement compatible avec un cisaillement top-vers-le sud dans la partie supérieure de la nappe; la deuxième produit un intense plissement qui accompagne la mise en place de la nappe vers le nord. Ces deux phases de déformation témoignent d'un mécanisme d'exhumation par déformation ductile d'un bloc cohérent.
Resumo:
Background: One of the main goals of cancer genetics is to identify the causative elements at the molecular level leading to cancer.Results: We have conducted an analysis of a set of genes known to be involved in cancer in order to unveil their unique features that can assist towards the identification of new candidate cancer genes. Conclusion: We have detected key patterns in this group of genes in terms of the molecular function or the biological process in which they are involved as well as sequence properties. Based on these features we have developed an accurate Bayesian classification model with which human genes have been scored for their likelihood of involvement in cancer.
Resumo:
The success of therapies for a number of pediatric disorders has posed new challenges for the long-term follow-up of adolescents with chronic endocrinopathies. Unfortunately, too many patients are lost during the transfer from pediatric to adult clinics. The transition process should be well-organized and include the young person and family. Recognizing the special needs of these adolescents is an important step in developing patient-centered approaches to care that enable patients to develop autonomy and self care skills. Key elements in this process include structured policies and guidelines, communication and close collaboration between pediatric and adult clinics, and integrating nurse clinicians in the transition process to help close the gaps in care.
Resumo:
This study tests the theory of rationing, examining changes in household consumption behavior during the transition to a market economy in Poland, 1987–92. A model of consumption under rationing is developed and fitted to prereform quarterly data from the Polish Household Budget Survey. Virtual prices, prices at which consumers would have voluntarily chosen the rationed levels of goods, are derived for food and housing. The prereform Almost Ideal Demand System (AIDS) model with rationing is estimated. Estimates from the virtual AIDS yield plausible values for price and income elasticities. The AIDS model (without rationing) is also fitted to postreform quarterly household survey data for comparison and evaluation. When the two sets of results are compared, the impacts of rationing are consistent with the theory. Own-price elasticities for nonrationed goods are larger after the reform, and there is increased complementarity and decreased substitutability for the nonrationed goods. The results for Poland show a 75 percent decline in real household welfare over the transition and this welfare loss is one-third the value obtained using reported prices.