On heterogeneous and homogeneous networks in a multilayered reality : clashing interests in the ethnic enclave of Lloret de Mar

Over the last decade, the tourist destination of Lloret de Mar (Gerona, Spain) has experienced an increasing concentration of souvenir stores owned by a population of Indian origin. Although Lloret de Mar is already a multicultural spot, Indians represent a small minority in Spain. In order to explain such a remarkable concentration and economic specialization in a low profit sector, we suggest the emergence of an ethnic enclave based on a triple articulation (entrepreneurs, employees and the local community). Our findings provide support for the mixed-embeddedness hypothesis, which contends that ethnic entrepreneurs in Europe need to rely on both the co-ethnic social networks and the linkages with the host society in order to run their business successfully. However, differential degrees of social integration amongst Indians themselves-clearly shown by the composition of their social networks-and between local dwellers and Indians suggest confronting interests amongst social agents in a highly complex and micro-social touristic site undergoing deep economic crisis. Throughout, a mixed-methods approach in the paper reveals the unequal social structure of the enclave, providing a better theoretical understanding of the difficulties and backgrounds in which minority migrant groups develop and expand their social relationships in the "host society

Mixed embeddedness of immigrant entrepreneurs in microstates : the case of Andorra

The theory of mixed embeddedness has been empirically tested in several countries showing how immigrant entrepreneurs utilize network resources coming from both the country of origin and residence, including institutions. Nevertheless, little attention has been paid to the networks of immigrant entrepreneurs residing in a microstate. Specific features of microstates may affect the way in which migrant entrepreneurs develop their ventures. Therefore, we collected the personal networks of 40 entrepreneurs through a mixed-method approach, in order to understand the mechanisms through which the microstate context affects entrepreneurs' support networks. Our results indicate that in Andorra migrants need higher levels of support from people settled in or close to Andorra in comparison to immigrants in other contexts. Contacts in the sending country only play a secondary role.La teoría de la integración mixta se ha probado empíricamente en varios países mostrando cómo los empresarios inmigrantes utilizan recursos de red provenientes tanto del país de origen como de residencia, incluidas las instituciones. Sin embargo, se ha prestado poca atención a las redes de empresarios inmigrantes que residen en un microestado. Las características específicas de los microestados pueden afectar la forma en que los empresarios migrantes desarrollan sus emprendimientos. Por lo tanto, recopilamos las redes personales de 40 empresarios a través de un enfoque de métodos mixtos, con el fin de comprender los mecanismos a través de los cuales el contexto de los microestados afecta las redes de apoyo de los emprendedores. Nuestros resultados indican que en Andorra los inmigrantes necesitan mayores niveles de apoyo de personas asentadas en o cerca de Andorra en comparación con inmigrantes en otros contextos. Los contactos en el país de origen solo juegan un rol secundario

Las redes sociales de la economía social

A partir del trabajo de campo en curso llevado a cabo en Cataluña (proyecto de investigación ENCLAVE - CSO2012-32635), se sugiere la existencia de al menos tres tipos de los llamados "empresarios sociales": los profesionales desplazados por los recortes en el gasto público en los sectores de la salud, los servicios sociales y la cooperación; las cooperativas y las asociaciones tradicionales, re-etiquetados como "empresarios sociales" o "empresas sociales" (conversos) y, por último, los que gozan de apoyo institucional público y privado para el desarrollo de sus iniciativas sociales o ambientales (elegidos). Con el fin de contrastar algunas de las hipótesis que plantea la literatura sobre los emprendedores sociales (a saber, su capacidad para movilizar recursos locales y lograr la participación de una amplia gama de actores para el logro de sus fines), se recogieron redes personales de casos de emprendedores sociales con la ayuda de EgoNet (http:// sourceforge.net/projects/egonet) utilizando un generador múltiple de nombres para obtener datos sobre personas relacionadas con la iniciativa. Las redes personales de estos tres tipos se resumieron mediante "grafos agrupados"(http://visone.info/wiki/index.php/Personal_networks_%28tutorial%29, los cuales presentan diferentes características para cada tipo, en términos de equilibrio entre lazos fuertes y débiles de apoyo a la iniciativa empresarial. Sostenemos que este nuevo escenario en el que nuevos y viejos actores se esfuerzan por presentarse a sí mismos con las etiquetas disponibles difícilmente puede entenderse sólo en términos de las motivaciones sociales, como sugiere la literatura. Por último, se presenta una conceptualización del campo del "empresariado social" como consecuencia del avance del neoliberalismo y la reducción del gasto público destinado a las clases medias y populares en Europa a partir de la crisis financiera

Progressive Telomere Dysfunction Causes Cytokinesis Failure and Leads to the Accumulation of Polyploid Cells

Most cancer cells accumulate genomic abnormalities at a remarkably rapid rate, as they are unable to maintain their chromosome structure and number. Excessively short telomeres, a known source of chromosome instability, are observed in early human-cancer lesions. Besides telomere dysfunction, it has been suggested that a transient phase of polyploidization, in most cases tetraploidization, has a causative role in cancer. Proliferation of tetraploids can gradually generate subtetraploid lineages of unstable cells that might fire the carcinogenic process by promoting further aneuploidy and genomic instability. Given the significance of telomere dysfunction and tetraploidy in the early stages of carcinogenesis, we investigated whether there is a connection between these two important promoters of chromosomal instability. We report that human mammary epithelial cells exhibiting progressive telomere dysfunction, in a pRb deficient and wild-type p53 background, fail to complete the cytoplasmatic cell division due to the persistence of chromatin bridges in the midzone. Flow cytometry together with fluorescence in situ hybridization demonstrated an accumulation of binucleated polyploid cells upon serial passaging cells. Restoration of telomere function through hTERT transduction, which lessens the formation of anaphase bridges by recapping the chromosome ends, rescued the polyploid phenotype. Live-cell imaging revealed that these polyploid cells emerged after abortive cytokinesis due to the persistence of anaphase bridges with large intervening chromatin in the cleavage plane. In agreement with a primary role of anaphase bridge intermediates in the polyploidization process, treatment of HMEC-hTERT cells with bleomycin, which produces chromatin bridges through illegimitate repair, resulted in tetraploid binucleated cells. Taken together, we demonstrate that human epithelial cells exhibiting physiological telomere dysfunction engender tetraploid cells through interference of anaphase bridges with the completion of cytokinesis. These observations shed light on the mechanisms operating during the initial stages of human carcinogenesis, as they provide a link between progressive telomere dysfunction and tetraploidy

Telomere disruption results in non-random formation of de novo dicentric chromosomes involving acrocentric human chromosomes

Copyright: © 2010 Stimpson et al.Genome rearrangement often produces chromosomes with two centromeres (dicentrics) that are inherently unstable because of bridge formation and breakage during cell division. However, mammalian dicentrics, and particularly those in humans, can be quite stable, usually because one centromere is functionally silenced. Molecular mechanisms of centromere inactivation are poorly understood since there are few systems to experimentally create dicentric human chromosomes. Here, we describe a human cell culture model that enriches for de novo dicentrics. We demonstrate that transient disruption of human telomere structure non-randomly produces dicentric fusions involving acrocentric chromosomes. The induced dicentrics vary in structure near fusion breakpoints and like naturally-occurring dicentrics, exhibit various inter-centromeric distances. Many functional dicentrics persist for months after formation. Even those with distantly spaced centromeres remain functionally dicentric for 20 cell generations. Other dicentrics within the population reflect centromere inactivation. In some cases, centromere inactivation occurs by an apparently epigenetic mechanism. In other dicentrics, the size of the alpha-satellite DNA array associated with CENP-A is reduced compared to the same array before dicentric formation. Extrachromosomal fragments that contained CENP-A often appear in the same cells as dicentrics. Some of these fragments are derived from the same alpha-satellite DNA array as inactivated centromeres. Our results indicate that dicentric human chromosomes undergo alternative fates after formation. Many retain two active centromeres and are stable through multiple cell divisions. Others undergo centromere inactivation. This event occurs within a broad temporal window and can involve deletion of chromatin that marks the locus as a site for CENP-A maintenance/replenishment.This work was supported by the Tumorzentrum Heidelberg/Mannheim grant (D.10026941)and by March of Dimes Research Foundation grant #1-FY06-377 and NIH R01 GM069514

On heterogeneous and homogeneous networks in a multilayered reality : clashing interests in the ethnic enclave of Lloret de Mar

Over the last decade, the tourist destination of Lloret de Mar (Gerona, Spain) has experienced an increasing concentration of souvenir stores owned by a population of Indian origin. Although Lloret de Mar is already a multicultural spot, Indians represent a small minority in Spain. In order to explain such a remarkable concentration and economic specialization in a low profit sector, we suggest the emergence of an ethnic enclave based on a triple articulation (entrepreneurs, employees and the local community). Our findings provide support for the mixed-embeddedness hypothesis, which contends that ethnic entrepreneurs in Europe need to rely on both the co-ethnic social networks and the linkages with the host society in order to run their business successfully. However, differential degrees of social integration amongst Indians themselves-clearly shown by the composition of their social networks-and between local dwellers and Indians suggest confronting interests amongst social agents in a highly complex and micro-social touristic site undergoing deep economic crisis. Throughout, a mixed-methods approach in the paper reveals the unequal social structure of the enclave, providing a better theoretical understanding of the difficulties and backgrounds in which minority migrant groups develop and expand their social relationships in the "host society

Las redes sociales de la economía social

A partir del trabajo de campo en curso llevado a cabo en Cataluña (proyecto de investigación ENCLAVE - CSO2012-32635), se sugiere la existencia de al menos tres tipos de los llamados "empresarios sociales": los profesionales desplazados por los recortes en el gasto público en los sectores de la salud, los servicios sociales y la cooperación; las cooperativas y las asociaciones tradicionales, re-etiquetados como "empresarios sociales" o "empresas sociales" (conversos) y, por último, los que gozan de apoyo institucional público y privado para el desarrollo de sus iniciativas sociales o ambientales (elegidos). Con el fin de contrastar algunas de las hipótesis que plantea la literatura sobre los emprendedores sociales (a saber, su capacidad para movilizar recursos locales y lograr la participación de una amplia gama de actores para el logro de sus fines), se recogieron redes personales de casos de emprendedores sociales con la ayuda de EgoNet (http:// sourceforge.net/projects/egonet) utilizando un generador múltiple de nombres para obtener datos sobre personas relacionadas con la iniciativa. Las redes personales de estos tres tipos se resumieron mediante "grafos agrupados" (http://visone.info/wiki/index.php/Personal_networks_%28tutorial%29, los cuales presentan diferentes características para cada tipo, en términos de equilibrio entre lazos fuertes y débiles de apoyo a la iniciativa empresarial. Sostenemos que este nuevo escenario en el que nuevos y viejos actores se esfuerzan por presentarse a sí mismos con las etiquetas disponibles difícilmente puede entenderse sólo en términos de las motivaciones sociales, como sugiere la literatura. Por último, se presenta una conceptualización del campo del "empresariado social" como consecuencia del avance del neoliberalismo y la reducción del gasto público destinado a las clases medias y populares en Europa a partir de la crisis financiera.Drawing on the ongoing fieldwork carried out in Catalonia (research project ENCLAVE, CSO2012-32635), we suggest the existence of at least three types of the so-called "social entrepreneurs": the self-occupied individuals displaced by the cuts on public spending in the health, social and cooperation sectors; the traditional Coops and associations, re-labelled as "social entrepreneurs" or "social enterprises", and, finally, the ones that enjoyed institutional support (both from public, and private entrepreneurship programs) which fuelled their (social/environmental) initiatives.In order to test the networking hypothesis posed by the literature (i.e. social entrepreneurs are distinguished by their capability for mobilizing local resources and involving a wide range of actors for achieving their ends), we collected personal network data with the aid of EgoNet (http://sourceforge.net/projects/egonet) using multiple name generators for eliciting alters related with the initiative. The personal networks of these three types are summarized using "clustered graphs" (http://visone.info/wiki/index.php/Personal_networks_%28tutorial%29), whom exhibit different features for each type in terms of the balance of weak/strong ties and support to the social initiative. We argue that this new arena in which new and old players struggle to present themselves and survive can hardly be understood just in terms of social motivations, as the literature suggests. Finally, a discussion about the conceptualization of "social entrepreneurship" as an outcome of the rise of neoliberalism and the cuts in public spending provoked by the financial crisis in Europe will be presented