Peak and persistent excess of genetic diversity following an abrupt migration increase.

Genetic diversity is essential for population survival and adaptation to changing environments. Demographic processes (e.g., bottleneck and expansion) and spatial structure (e.g., migration, number, and size of populations) are known to shape the patterns of the genetic diversity of populations. However, the impact of temporal changes in migration on genetic diversity has seldom been considered, although such events might be the norm. Indeed, during the millions of years of a species' lifetime, repeated isolation and reconnection of populations occur. Geological and climatic events alternately isolate and reconnect habitats. We analytically document the dynamics of genetic diversity after an abrupt change in migration given the mutation rate and the number and sizes of the populations. We demonstrate that during transient dynamics, genetic diversity can reach unexpectedly high values that can be maintained over thousands of generations. We discuss the consequences of such processes for the evolution of species based on standing genetic variation and how they can affect the reconstruction of a population's demographic and evolutionary history from genetic data. Our results also provide guidelines for the use of genetic data for the conservation of natural populations.

Induction of transendothelial migration in normal and malignant human T lymphocytes.

Activated CD 3+ enriched human peripheral blood T cells exhibited potent capacity for transendothelial migration through HUVEC layers in the absence of T cell ***. In contrast, malignant human T cell lines *** no or negligible ability of transendothelial migration in the absence of chemoattractants. Time lapse studies of transendothelial migration of activated CD 3+ enriched peripheral blood T cells through a HUVEC layer showed that the first T cells were detected in the lower compartment of a tissue culture insert after 1 hour and that migration increased to reach a maximum of 25 x 10(4) T cells/hr after 24 hours. Adhesion assays of human T cell lines demonstrated that all T cell lines were capable of adhesion to HUVEC and that adhesion of T cells to HUVECs was primarily mediated by CD11a/CD18 and ICAM-1 interactions. Furthermore, transendothelial migration of CD 3+ enriched human peripheral blood T cells was inhibited by pretreating the T cells with anti-CD 18 monoclonal antibodies. The inability of malignant T cells to migrate through HUVEC layers in the absence of chemoattractants was not due to poor motility per se, since both normal and malignant T cells migrated well on extracellular matrix components as determined by using Boyden chambers. Crosslinking of alpha 1 beta 2 and alpha 4 beta 1 with immobilized monoclonal antibodies induced motile behaviour in activated CD 3 enriched human peripheral blood T cells but not in malignant T cell lines. In conclusion, the differences in the ability of transendothelial migration between normal and malignant human T cells in the absence of chemoattractants is primarily due to the differences in the capacity of alpha 1 beta 2 and alpha 4 beta 1 to trigger motile behaviour in the separate cell types.

Transcriptional activation of the macrophage migration-inhibitory factor gene by the corticotropin-releasing factor is mediated by the cyclic adenosine 3',5'- monophosphate responsive element-binding protein CREB in pituitary cells.

Macrophage migration-inhibitory factor (MIF) has recently been identified as a pituitary hormone that functions as a counterregulatory modulator of glucocorticoid action within the immune system. In the anterior pituitary gland, MIF is expressed in TSH- and ACTH-producing cells, and its secretion is induced by CRF. To investigate MIF function and regulation within pituitary cells, we initiated the characterization of the MIF 5'-regulatory region of the gene. The -1033 to +63 bp of the murine MIF promoter was cloned 5' to a luciferase reporter gene and transiently transfected into freshly isolated rat anterior pituitary cells. This construct drove high basal transcriptional activity that was further enhanced after stimulation with CRF or with an activator of adenylate cyclase. These transcriptional effects were associated with a concomitant rise in ACTH secretion in the transfected cells and by an increase in MIF gene expression as assessed by Northern blot analysis. A cAMP-responsive element (CRE) was identified within the MIF promoter region which, once mutated, abolished the cAMP responsiveness of the gene. Using this newly identified CRE, DNA-binding activity was detected by gel retardation assay in nuclear extracts prepared from isolated anterior pituitary cells and AtT-20 corticotrope tumor cells. Supershift experiments using antibodies against the CRE-binding protein CREB, together with competition assays and the use of recombinant CREB, allowed the detection of CREB-binding activity with the identified MIF CRE. These data demonstrate that CREB is the mediator of the CRF-induced MIF gene transcription in pituitary cells through an identified CRE in the proximal region of the MIF promoter.

Do women in female-dominated occupations exit the labour market more? Evidence from Italy, Spain, Denmark and the UK

Literature on sex occupational segregation has typically focused on the micro and macro determinants of it, on mobility patterns over the life course, on implications of segregation and mobility for gender inequalities. Rarely the link between sex-type occupations and women’s risk of labour market interruptions over family formation has been explored. In this piece of work we shall analyse whether women who are working in the female-dominated, male-dominated or integrated occupations have more or less chances to remain attached to the labour market, controlling for qualifications, class, sector and contract positions. By drawing from ECHP, and comparing Italy, Spain, Denmark and the UK, we shall in particular see whether such connection varies across countries with different institutional and cultural configurations.We find that, ceteris paribus, only in the UK the sex-composition of an occupation matters: women in female occupations are more likely to move to inactivity than women in mixed or male occupations. In the other countries considered the main cleavages lie elsewhere. In Italy what matters most is the sector of employment (public vs. private). In Spain the sector is relevant too, but also social class and the type of contract held (permanent vs. temporary). In Denmark women’s transitions to inactivity are largely independent of human capital and job characteristics.

Leaving the labour market: event-history analysis of the female workers' transition to housework in Denmark, Germany, Great Britain and Spain

This paper is aimed at exploring the determinants of female activity from a dynamic perspective. An event-history analysis of the transition form employment to housework has been made resorting to data from the European Household Panel Survey. Four countries representing different welfare regimes and, more specifically, different family policies, have been selected for the analysis: Britain, Denmark, Germany and Spain. The results confirm the importance of individual-level factors, which is consistent with an economic approach to female labour supply. Nonetheless, there are significant cross-national differences in how these factors act over the risk of abandoning the labour market. First, the number of trnasitions is much lower among Danish working women than among British, German or Spanish ones, revealing the relative importance of universal provision of childcare services, vis-à-vis other elements of the family policy, as time or money.

Gendered networks and Mexican migration

In this paper, we investigate how the gendered origin of migrant networks (i.e. matrilineal vs. patrilineal) is associated with aspirations to migrate and subsequent migration behavior. Using longitudinal data from the Mexican Family Life Survey (MxFLS), we follow 3,923 married couples across 139 municipalities over the 2002-2005 period. We find that the networks of both the individual and her/his spouse are associated with aspiring to migrate to the United States. However, one’s own network matters most (i.e. matrilineal networks for women and patrilineal networks for men). On the other hand, in terms of behavior, only matrilineal networks predict a subsequent move to the U.S. for men and women/couples, who are assessed jointly. These findings suggest that our understanding of the role of migrant networks in perpetuating male-centered, labor migration does not necessarily translate once a union has formed. We make the case that future work would do well to account for not only the presence and composition of networks, but also their origin, which in certain circumstances may be the most relevant factor.

Temporary and circular labour migration : reassessing established public policies

Today, Temporary Labour Migration is a fundamental course of action promoted by relevant economic and political agents, such as EC, the GCIM, or the OECD. Based on a specific empirical case study of Temporary and Circular Labour Migration in the Catalonian agrarian sector, which has been distinguished as a particularly successful formula, we identify a new area of interest: the emergence of a new empirical migrant category, the Circular Labour Migrant, which remains theoretically unnamed and lacks public recognition. We argue that, until now, there have been two historical phases regarding temporary labour migration: one of total deregulation and another of partial regulation, led by private actors with support from public institutions, and featuring circularity. IN a developed Welfare State context, it would be normatively pertinent to except a step towards a third phase, one involving the institutionalization of this new mobility category through the elaboration of a public policy.

Female stereotypes in household appliances advertising and their social role in Spain: the perpetuation of a no- longer-existing female condition

The following dissertation proposes a qualitative approach on the matter ofadvertising, society and construction of identity, based on the effect of householdappliances commercials in constructing female identity of Spanish women today.Conclusions will be drawn based on a juxtaposition of social background andadvertising content and on how Spanish women of today perceive the evolution offemale imagery depicted in advertisements. The aim is to demonstrate how muchcommercials mirrors society and how far it reinforces paradigms no longer existing

Role of the superior parietal lobules in letter-identity processing within strings: FMRI evidence from skilled and dyslexic readers.

Traditionally, the ventral occipito-temporal (vOT) area, but not the superior parietal lobules (SPLs), is thought as belonging to the neural system of visual word recognition. However, some dyslexic children who exhibit a visual attention span disorder - i.e. poor multi-element parallel processing - further show reduced SPLs activation when engaged in visual multi-element categorization tasks. We investigated whether these parietal regions further contribute to letter-identity processing within strings. Adult skilled readers and dyslexic participants with a visual attention span disorder were administered a letter-string comparison task under fMRI. Dyslexic adults were less accurate than skilled readers to detect letter identity substitutions within strings. In skilled readers, letter identity differs related to enhanced activation of the left vOT. However, specific neural responses were further found in the superior and inferior parietal regions, including the SPLs bilaterally. Two brain regions that are specifically related to substituted letter detection, the left SPL and the left vOT, were less activated in dyslexic participants. These findings suggest that the left SPL, like the left vOT, may contribute to letter string processing.

Late migration of percutaneous bio-absorbable devices--a word of caution.

BACKGROUND: Closures of atrial septal defects or a patent foramen ovale (PFO) are increasingly performed percutaneously. The experience of late migration of a new bio-absorbable device is presented here, followed by conceptual discussion. METHODS: Six months post PFO closure with a BioSTAR® device a patient presented with chest pain. Echocardiography showed a hyperechogenic structure perforating the aortic wall. RESULTS: Surgical exploration showed a perforation of the ascending aorta by one metallic, non absorbable arm. This is the second case of late (>6 months) dislocation of the residual framework of the occluder. CONCLUSIONS: The overall incidence of perforation of cardiac structures due to secondary dislocation is low. However this complication exists and should kept in mind in symptomatic patients with new onset of chest pain, after percutaneous procedures. The concept of biodegradation, with residual, non absorbable metal braiding, should be reviewed, analyzing in particular long term results and incidence of secondary dislocation.

Breeding rate is associated with pheomelanism in male and with eumelanism in female barn owls

Melanin-based coloration exists in 2 types: black eumelanism and reddish-brown pheomelanism, which both have a strong heritable component. To test whether these 2 types of melanism are associated with alternative adaptations, we carried out a correlative study over 8 years and an experiment in a Swiss population of barn owls, Tyto alba. This species varies in coloration from reddish-brown to white and from lightly to heavily marked with black spots. Based on the fact that plumage coloration and spottiness are male- and female-specific secondary sexual characters, respectively, we examined whether the probability of breeding is associated with the degree of pheomelanism in males and of eumelanism in females. In males, recruited nestlings were significantly less reddish-brown than their nonrecruited nest mates. In females, individuals displaying larger black spots started to breed at a younger age and had a higher survival, and females with experimentally reduced plumage spottiness bred less often than control females. Therefore, in the barn owl, the degree of male pheomelanism is associated with the probability of being recruited in the local population, whereas the degree of female eumelanism correlates with age at sexual maturity, survival probability, and also the probability of skipping reproduction.

Histone deacetylase inhibitors repress macrophage migration inhibitory factor (MIF) expression by targeting MIF gene transcription through a local chromatin deacetylation.

The cytokine macrophage migration inhibitory factor plays a central role in inflammation, cell proliferation and tumorigenesis. Moreover, macrophage migration inhibitory factor levels correlate with tumor aggressiveness and metastatic potential. Histone deacetylase inhibitors are potent antitumor agents recently introduced in the clinic. Therefore, we hypothesized that macrophage migration inhibitory factor would represent a target of histone deacetylase inhibitors. Confirming our hypothesis, we report that histone deacetylase inhibitors of various chemical classes strongly inhibited macrophage migration inhibitory factor expression in a broad range of cell lines, in primary cells and in vivo. Nuclear run on, transient transfection with macrophage migration inhibitory factor promoter reporter constructs and transduction with macrophage migration inhibitory factor expressing adenovirus demonstrated that trichostatin A (a prototypical histone deacetylase inhibitor) inhibited endogenous, but not episomal, MIF gene transcription. Interestingly, trichostatin A induced a local and specific deacetylation of macrophage migration inhibitory factor promoter-associated H3 and H4 histones which did not affect chromatin accessibility but was associated with an impaired recruitment of RNA polymerase II and Sp1 and CREB transcription factors required for basal MIF gene transcription. Altogether, this study describes a new molecular mechanism by which histone deacetylase inhibitors inhibit MIF gene expression, and suggests that macrophage migration inhibitory factor inhibition by histone deacetylase inhibitors may contribute to the antitumorigenic effects of histone deacetylase inhibitors.

Microarray and RNAi Analysis of P450s in Anopheles gambiae Male and Female Steroidogenic Tissues: CYP307A1 Is Required for Ecdysteroid Synthesis.

In insects, the steroid hormone 20-hydroxyecdysone (20E) coordinates major developmental transitions. While the first and the final steps of 20E biosynthesis are characterized, the pathway from 7-dehydrocholesterol to 5β-ketodiol, commonly referred as the "black box", remains hypothetical and whether there are still unidentified enzymes is unknown. The black box would include some oxidative steps, which are believed to be mediated by P450 enzymes. To identify new enzyme(s) involved in steroid synthesis, we analyzed by small-scale microarray the expression of all the genes encoding P450 enzymes of the malaria mosquito Anopheles gambiae in active steroidogenic organs of adults, ovaries from blood-fed females and male reproductive tracts, compared to inactive steroidogenic organs, ovaries from non-blood-fed females. Some genes encoding P450 enzymes were specifically overexpressed in female ovaries after a blood-meal or in male reproductive tracts but only three genes were found to be overexpressed in active steroidogenic organs of both females and males: cyp307a1, cyp4g16 and cyp6n1. Among these genes, only cyp307a1 has an expression pattern similar to other mosquito steroidogenic genes. Moreover, loss-of-function by transient RNAi targeting cyp307a1 disrupted ecdysteroid production demonstrating that this gene is required for ecdysteroid biosynthesis in Anopheles gambiae.