990 resultados para Total migration downtime
Resumo:
We herein describe in full detail the first total synthesis of the antitumor agents neolaulimalide and isolaulimalide as well as a highly efficient route to laulimalide. A Kulinkovich reaction followed by a cyclopropyl-allyl rearrangement is used to install the exo-methylene group. The C(2)-C(16) aldehyde fragment is coupled with the C(17)-C(28) sulfone fragments by a highly (E)-selective Julia-Lythgoe-Kocienski olefination to deliver the key intermediates of all three syntheses. Various conditions for the Yamaguchi macrolactonization are applied to close the individual macrocycles. Finally a carefully elaborated endgame was developed to solve the problem of acyl migration in the case of neolaulimalide. All compounds were tested against several cell lines. The cytotoxicity of neolaulimalide could be confirmed for the first time since its original isolation and it could be shown that it induces tubulin polymerization as efficiently as laulimalide.
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The distribution of C1 to C8 hydrocarbons in sediment samples from DSDP Leg 75, Hole 530A, indicates that significant amounts of methane and ethane have migrated from organic-rich to organic-lean shales in close proximity. Most compounds larger than ethane are not migrating out of black shales, where they occur in high concentrations. These results lead to a general model for assessing migration. In addition, three shale types are identified on the basis of organic carbon and pyrolysis products and patterns.
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The eastern tropical North Atlantic (ETNA) features a mesopelagic oxygen minimum zone (OMZ) at approximately 300-600 m depth. Here, oxygen concentrations rarely fall below 40 µmol O2 kg-1, but are expected to decline under future projections of global warming. The recent discovery of mesoscale eddies that harbour a shallow suboxic (<5 µmol O2 kg-1) OMZ just below the mixed layer could serve to identify zooplankton groups that may be negatively or positively affected by on-going ocean deoxygenation. In spring 2014, a detailed survey of a suboxic anticyclonic modewater eddy (ACME) was carried out near the Cape Verde Ocean Observatory (CVOO), combining acoustic and optical profiling methods with stratified multinet hauls and hydrography. The multinet data revealed that the eddy was characterized by an approximately 1.5-fold increase in total area-integrated zooplankton abundance. At nighttime, when a large proportion of acoustic scatterers is ascending into the upper 150 m, a drastic reduction in mean volume backscattering (Sv, shipboard ADCP, 75kHz) within the shallow OMZ of the eddy was evident compared to the nighttime distribution outside the eddy. Acoustic scatterers were avoiding the depth range between about 85 to 120 m, where oxygen concentrations were lower than approximately 20 µmol O2 kg-1, indicating habitat compression to the oxygenated surface layer. This observation is confirmed by time-series observations of a moored ADCP (upward looking, 300kHz) during an ACME transit at the CVOO mooring in 2010. Nevertheless, part of the diurnal vertical migration (DVM) from the surface layer to the mesopelagic continued through the shallow OMZ. Based upon vertically stratified multinet hauls, Underwater Vision Profiler (UVP5) and ADCP data, four strategies have been identified to be followed by zooplankton in response to the eddy OMZ: i) shallow OMZ avoidance and compression at the surface (e.g. most calanoid copepods, euphausiids), ii) migration to the shallow OMZ core during daytime, but paying O2 debt at the surface at nighttime (e.g. siphonophores, Oncaea spp., eucalanoid copepods), iii) residing in the shallow OMZ day and night (e.g. ostracods, polychaetes), and iv) DVM through the shallow OMZ from deeper oxygenated depths to the surface and back. For strategy i), ii) and iv), compression of the habitable volume in the surface may increase prey-predator encounter rates, rendering zooplankton and micronekton more vulnerable to predation and potentially making the eddy surface a foraging hotspot for higher trophic levels. With respect to long-term effects of ocean deoxygenation, we expect avoidance of the mesopelagic OMZ to set in if oxygen levels decline below approximately 20 µmol O2 kg-1. This may result in a positive feedback on the OMZ oxygen consumption rates, since zooplankton and micronekton respiration within the OMZ as well as active flux of dissolved and particulate organic matter into the OMZ will decline.
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Studies detailing synthetic approaches to a variety of biosynthetically related vibsanin-type diterpenes (i.e. vibsanin E, 15-O-methylcyclovibsanin B, 3-hydroxy-vibsanin E, furano-vibsanin A, and 3-O-methylfuranovibsanin A) are discussed. Biogenetically modelled approaches are coupled with an in-vestigation of classical and modern six- to seven-membered ring-expansion protocols, which gain access to the central core of these natural products. (c) Wiley-VCH Verlag GmbH & Co.
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This article analyses the motivations for return migration among the Ecuadorians and Bolivians who, after living in Spain, returned to their countries of origin during the economic crisis that started in 2008. From the analysis of 22 interviews in-depth which took place in Ecuador and 38 in Bolivia to women, men and young people from migrant families, this decision-making process is shown to be embedded into a gendered dynamics of relationships. Particular detail is given to affective and economic elements that had an influence on the decision to return, as well as to the strategies deployed to project their readjustment back in origin. Males and females occupy differential positions within the family, work and social circle, their expectations being built in a gendered manner. Despite the fact migration has brought women greater economic power within the family group, their reintegration upon return redefines their role as main managers in the household and the dynamics that allow their social reproduction. Men, for their part, aspire to refresh their role as providers in spite of their frail labour position upon return. Social mobility for females is passed on through generations by a strong investment on education for their daughters and sons, while for males this mobility revolves around setting up family businesses and around their demonstrative abilities.
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This text deals with transnational strategies of social mobility in Ecuadorian migrant households in Spain. We apply the capital accumulation model (Moser, 2009) for this purpose. The main target of this article is, beyond thinking in terms of capital stock and accumulation, the analysis in depth of the dynamics of the different types of capital, that is to say, how they interact with each other in the framework of the social mobility strategies of the migrants and their families. We are bringing into light the way some households adopt investing decisions in capitals that don't translate into any addition or earnings in all cases, on the contrary, concentrating all their efforts on the accumulation of a certain asset they may, in some cases, lead to a loss of another. We will concentrate our analysis primarily on the dynamics between the physical and financial capital and the social and emotional capital, showing the tensions produced between these two types of assets. At the same time, we will highlight how migrants negotiate their family strategies of social mobility in the transnational area. Our study is based in empirical material obtained from qualitative fieldwork (in-depth interviews) with families of migrants in the urban district of Turubamba Bajo -(south of Quito) and in Madrid. A series of households were selected where interviews were carried out in the country of origin as well as in the context of immigration, with different family members, analysing the transnational social and economic strategies of families of migrant members. Family members of migrants established in Spain were interviewed in Quito, as well as key informants in the district (school teachers, nursery members of the staff, etc.). The research was framed within the projects "Impact of migration on the development: gender and transnationalism", Ministry of Science and Innovation (SEJ2007/63179) (Laura Oso, dir. 2007-2010),"Gender, transnationalism and intergenerational strategies of social mobility", Ministry of Economy and Competitiveness (FEM2011/26210) (Laura Oso, dir. 201-1-2015) and “Gender, Crossed Mobilities and Transnational Dynamics”, Ministry of Economy and Competitiveness (FEM2015-67164).
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Care has come to dominate much feminist research on globalized migrations and the transfer of labor from the South to the North, while the older concept of reproduction had been pushed into the background but is now becoming the subject of debates on the commodification of care in the household and changes in welfare state policies. This article argues that we could achieve a better understanding of the different modalities and trajectories of care in the reproduction of individuals, families, and communities, both of migrant and nonmigrant populations by articulating the diverse circuits of migration, in particular that of labor and the family. In doing this, I go back to the earlier North American writing on racialized minorities and migrants and stratified social reproduction. I also explore insights from current Asian studies of gendered circuits of migration connecting labor and marriage migrations as well as the notion of global householding that highlights the gender politics of social reproduction operating within and beyond households in institutional and welfare architectures. In contrast to Asia, there has relatively been little exploration in European studies of the articulation of labor and family migrations through the lens of social reproduction. However, connecting the different types of migration enables us to achieve a more complex understanding of care trajectories and their contribution to social reproduction.
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Research on the relationship between reproductive work and women´s life trajectories including the experience of labour migration has mainly focused on the case of relatively young mothers who leave behind, or later re-join, their children. While it is true that most women migrate at a younger age, there are a significant number of cases of men and women who move abroad for labour purposes at a more advanced stage, undertaking a late-career migration. This is still an under-estimated and under-researched sub-field that uncovers a varied range of issues, including the global organization of reproductive work and the employment of migrant women as domestic workers late in their lives. By pooling the findings of two qualitative studies, this article focuses on Peruvian and Ukrainian women who seek employment in Spain and Italy when they are well into their forties, or older. A commonality the two groups of women share is that, independently of their level of education and professional experience, more often than not they end up as domestic and care workers. The article initially discusses the reasons for late-career female migration, taking into consideration the structural and personal determinants that have affected Peruvian and Ukrainian women’s careers in their countries of origin and settlement. After this, the focus is set on the characteristics of domestic employment at later life, on the impact on their current lives, including the transnational family organization, and on future labour and retirement prospects. Apart from an evaluation of objective working and living conditions, we discuss women’s personal impressions of being domestic workers in the context of their occupational experiences and family commitments. In this regard, women report varying levels of personal and professional satisfaction, as well as different patterns of continuity-discontinuity in their work and family lives, and of optimism towards the future. Divergences could be, to some extent, explained by the effect of migrants´ transnational social practices and policies of states.
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This article explores forms of migrant families’ reorganization within a (new) global economic crisis and the hardening of migration control in Europe; based on the cases of Dominican and Brazilian migration to Spain.Our goal is not to characterize the wholeness of strategies from these collectives, instead visualize its heterogeneity. Displacement of Dominican and Brazilian population to Spain shares the role of women as the first link of migration chains. In both cases women are the economic support of transnational families and they lead reunification's processes. Nevertheless, differences in the time spent in the destination country, migratory status, origin (rural-urban), level of education, class and labor insertion in destination country, affect differently, the planning and start up of migration projects, the organization of care and family reunification strategies. These findings question the predominant place granted to national origin in the study of international migration.
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This paper analyzes the impact of Spain’s economic crisis on social reproduction strategies of Ecuadorian migrant families in Madrid and Quito. The paper analyzes circular migration experiences and more permanent returns to Ecuador. I argue that these strategies and migrants' greater or lesser capabilities to move between different migration destinations show significant gender differences. On the one hand, men and women make a differential use of their migratory status to deploy transnational strategies and expand their mobility. On the other hand, migrants’ degree of mobility and flexibility with regard to the labor market and transnational social reproduction are derivative of a specific gendered order and sexual division of labor.
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At all normative levels, family migration law can disproportionally and negatively affect immigrant women’s rights in this field, producing gendered effects. In some cases, such effects are related to the normative and judicial imposition of unviable family-related models (e.g., the ʻgood mother ̕ the one-breadwinner family, or a rigid distinction between productive and reproductive work). In other cases, they are due to family migration law’s overlooking of the specific needs and difficulties of immigrant women, within their families and in the broader context of their host countries’ social and normative framework.To effectively expose and correct this gender bias, in this article I propose an alternative view of immigrant women’s right to family life, as a cluster of rights and entitlements rather than as a mono-dimensional right. As a theoretical approach, this construction is better equipped to capture the complex experiences of immigrant women in the European legal space, and to shed light on the gendered effects generated not by individual norms but by the interaction of norms that are traditionally assigned to separated legal domains (e.g., immigration law and criminal law). As a judicial strategy, this understanding is capable of prompting a consideration by domestic and supranational courts of immigrant women not as isolated individuals, but as ‘individuals in context’. I shall define this type of approach as ‘contextual interpretation’, understood as the consideration of immigrant women in the broader contexts of their families, their host societies and the normative frameworks applicable to them. Performed in a gendersensitive manner, a contextual judicial interpretation has the potential to neutralize the gendered effects of certain family migration norms. To illustrate these points, I will discuss selected judicial examples offered by the European Court on Human Rights, as well as from domestic jurisdictions of countries with a particularly high incidence of immigrant women (Italy and Spain).
Resumo:
International migration sets in motion a range of significant transnational processes that connect countries and people. How migration interacts with development and how policies might promote and enhance such interactions have, since the turn of the millennium, gained attention on the international agenda. The recognition that transnational practices connect migrants and their families across sending and receiving societies forms part of this debate. The ways in which policy debate employs and understands transnational family ties nevertheless remain underexplored. This article sets out to discern the understandings of the family in two (often intermingled) debates concerned with transnational interactions: The largely state and policydriven discourse on the potential benefits of migration on economic development, and the largely academic transnational family literature focusing on issues of care and the micro-politics of gender and generation. Emphasizing the relation between diverse migration-development dynamics and specific family positions, we ask whether an analytical point of departure in respective transnational motherhood, fatherhood or childhood is linked to emphasizing certain outcomes. We conclude by sketching important strands of inclusions and exclusions of family matters in policy discourse and suggest ways to better integrate a transnational family perspective in global migration-development policy.