Genetic structure in the Mediterranean seagrass Posidonia oceanica: disentangling past vicariance events from contemporary patterns of gene flow

The Mediterranean Sea is a two-basin system, with the boundary zone restricted to the Strait of Sicily and the narrow Strait of Messina. Two main population groups are recognized in the Mediterranean endemic seagrass Posidonia oceanica, corresponding to the Western and the Eastern basins. To address the nature of the East–West cleavage in P. oceanica, the main aims of this study were: (i) to define the genetic structure within the potential contact zone (i.e. the Strait of Sicily) and clarify the extent of gene flow between the two population groups, and (ii) to investigate the role of present water circulation patterns vs. past evolutionary events on the observed genetic pattern. To achieve these goals, we utilized SSR markers and we simulated, with respect to current regime, the possible present-day dispersal pattern of Posidonia floating fruits using 28-day numerical Lagrangian trajectories. The results obtained confirm the presence of the two main population groups, without any indices of reproductive isolation, with the break zone located at the level of the Southern tip of Calabria. The populations in the Strait of Sicily showed higher affinity with Western than with Eastern populations. This pattern of genetic structure probably reflects historical avenues of recolonization from relict glacial areas and past vicariance events, but seems to persist as a result of the low connectivity among populations via marine currents, as suggested by our dispersal simulation analysis

Trabalho precário e precarização institucional nos Estados Unidos Precarious work and the institutional precarization in the United States

Este artigo analisa as bases institucionais do trabalho precário nos Estados Unidos através de um duplo processo de precarização: da relação contratual tradicional e, dada a fragmentação do quadro institucional, a inadaptação da lei trabalhista dos Estados Unidos. O texto procura enfatizar a importância do estatuto do trabalhador - a relação contratual de emprego - para o acesso do mesmo aos direitos e benefícios sociais básicos. Os efeitos da recente crise econômica e a resposta das políticas públicas são discutidos na conclusão.<br>We analyze the institutional underpinnings of precarious work in the United States through a double process of precarization: of the traditional contractual relationship and given the fragmented institutional framework and the inadaptation of U.S. labor law. The importance of the employee status - the contractual employment relationship - for access to social rights and basic benefits is emphasized. Effects of the recent economic crisis and public policy response are discussed in conclusion

Ocean governance and risk management

The high seas have always engendered a range of emotions and reactions from humans. Curiosity, fear, even terror, of this great expanse of ocean which cover 70 % of Earth the blue planet. Yet the sheer size of the oceans and the difficulty of transporting across them meant the high seas were largely ignored by the vast majority of humans for centuries. Humans were largely confined to land with the only interest in the seas being as trade routes and the defence of the land. In fact all the way up to the last quarter of the twentieth century a nations territorial sea extended only three nautical miles off shore the distance that a cannon ball could be fired.This almost casual relationship to the oceans changed dramatically in the 1960s and 1970s as technology played an ever icnreasing role in the exploitation of the natural resources of the seas. Fishing was made far easier by being able to use sophisticated sonar systems to detect the fish and by advanced nets and vessels. But it was probably the technological ability to first find and then extract oil and gas off shore on continental shelfs, and at increasing depths, which stimulated interest in exploiting marine resources. Dreams of other deep sea mineral resources (e.g. manganese nodules) simply fuelled interest in the oceans, not to mentino some of the pharmaceuticals that were being discovered. <br /