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.

Pharmaceutical Generics, Vertical Product Differentiation, and Public Policy

This paper studies oligopolistic competition in off-patent pharmaceutical markets using a vertical product differentiation model. This model can explain the observation that countries with stronger regulations have smaller generic market shares. It can also explain the differences in observed regulatory regimes. Stronger regulation may be due to a higher proportion of production that is done by foreign firms. Finally, a closely related model can account for the observed increase in prices by patent owners after entry of generic producers.

Subcontracting and vertical integration in the Spanish cotton industry

This paper examines changes in the organization of the Spanish cotton industry from 1720 to 1860 in its core region of Catalonia. As the Spanish cotton industry adopted the most modern technology and experienced the transition to the factory system, cotton spinning and weaving mills became increasingly vertically integrated. Asset specificity more than other factors explained this tendency towards vertical integration. The probability for a firm of being vertically integrated was higher among firms located in districts with high concentration ratios and rose with size and the use of modern machinery. Simultaneously, subcontracting predominated in other phases of production and distribution where transaction costs appears to be less important.

Trade, migration and regional unemployment

We formulate a dynamic core-periphery model with frictions in the job matching process to study the interplay between trade costs, migration and regional unemploymentin the short- and long-run. We find that the spatial distribution of unemployment mirrors (inversely) the distribution of economic activities. Further, we highlight a contrast between the short-run and the long-run effects of trade-induced migration on regional unemployment. In particular, an inßow of immigrants from the periphery into the core reduces the unemployment gap in the short-run, but exacerbates unemployment disparities in the long-run.

Pharmaceutical generics, vertical product differentiation and public policy

This paper studies oligopolistic competition in off-patent pharmaceuticalmarkets using a vertical product differentiation model. This model canexplain the observation that countries with stronger regulations havesmaller generic market shares. It can also explain the differences inobserved regulatory regimes. Stronger regulation may be due to a higherproportion of production that is done by foreign firms. Finally, a closelyrelated model can account for the observed increase in prices by patentowners after entry of generic producers.

Credible redistributive policies and migration across US States

Does worker mobility undermine governments ability to redistribute income? Thispaper analyzes the experience of US states in the recent decades. We build a tractablemodel where both migration decisions and redistribution policies are endogenous. Wecalibrate the model to match skill premium and worker productivity at the state level,as well as the size and skill composition of migration flows. The calibrated modelis able to reproduce the large changes in skill composition as well as key qualitativerelationships of labor flows and redistribution policies observed in the data. Our resultssuggest that regional di¤erences in labor productivity are an important determinantof interstate migration. We use the calibrated model to compare the cross-section ofredistributive policies with and without worker mobility. The main result of the paperis that interstate migration has induced substantial convergence in tax rates acrossUS states, but no race to the bottom. Skill-biased in-migration has reduced the skillpremium and the need for tax-based redistribution in the states that would have hadthe highest tax rates in the absence of mobility.

Migration across Spanish provinces: Evidence from the social security records (1978-1992)

This paper uses Social Security records to study internal migrationin Spain. This is the first paper that uses this data source, whichhas some advantages with respect to existing data sources: it includesonly job-seeking migrants and it allows to identify temporary migration. Within the framework of an extended gravity model, we estimate a Generalized Negative Binomial regression on gross migration flows between provinces. We quantify the effect of local labor market imbalances on workers' mobility and discuss the equilibrating role of internal migration in Spain. Our main results show that the effect of employment opportunities have changed after 1984; migrants seem to be more responsive to economic conditions but, consistently with previous studies for the Spanish labor market, the migration response to wage differentials is wrongly signed. Our analysis also confirms the larger internal mobility of highly qualified workers.

Effects of convection on the removal of the multiplicity of stable states in one-dimensional vertical models

Here I develop a model of a radiative-convective atmosphere with both radiative and convective schemes highly simplified. The atmospheric absorption of radiation at selective wavelengths makes use of constant mass absorption coefficients in finite width spectral bands. The convective regime is introduced by using a prescribed lapse rate in the troposphere. The main novelty of the radiative-convective model developed here is that it is solved without using any angular approximation for the radiation field. The solution obtained in the purely radiation mode (i. e. with convection ignored) leads to multiple equilibria of stable states, being very similar to some results recently found in simple models of planetary atmospheres. However, the introduction of convective processes removes the multiple equilibria of stable states. This shows the importance of taking convective processes into account even for qualitative analyses of planetary atmosphere

States of maximum entropy production in a onedimensional vertical model with convective adjustment

We investigate the hypothesis that the atmosphere is constrained to maximize its entropy production by using a one-dimensional (1-D) vertical model. We prescribe the lapse rate in the convective layer as that of the standard troposphere. The assumption that convection sustains a critical lapse rate was absent in previous studies, which focused on the vertical distribution of climatic variables, since such a convective adjustment reduces the degrees of freedom of the system and may prevent the application of the maximum entropy production (MEP) principle. This is not the case in the radiative–convective model (RCM) developed here, since we accept a discontinuity of temperatures at the surface similar to that adopted in many RCMs. For current conditions, the MEP state gives a difference between the ground temperature and the air temperature at the surface ≈10 K. In comparison, conventional RCMs obtain a discontinuity ≈2 K only. However, the surface boundary layer velocity in the MEP state appears reasonable (≈3 m s-¹). Moreover, although the convective flux at the surface in MEP states is almost uniform in optically thick atmospheres, it reaches a maximum value for an optical thickness similar to current conditions. This additional result may support the maximum convection hypothesis suggested by Paltridge (1978)

Reelin controls progenitor cell migration in the healty and pathological adult brain

Understanding the signals that control migration of neural progenitor cells in the adult brain may provide new therapeutic opportunities. Reelin is best known for its role in regulating cell migration during brain development, but we now demonstrate a novel function for reelin in the injured adult brain. First, we show that Reelin is upregulated around lesions. Second, experimentally increasing Reelin expression levels in healthy mouse brain leads to a change in the migratory behavior of subventricular zone-derived progenitors, triggering them to leave the rostral migratory stream (RMS) to which they are normally restricted during their migration to the olfactory bulb. Third, we reveal that Reelin increases endogenous progenitor cell dispersal in periventricular structures independently of any chemoattraction but via cell detachment and chemokinetic action, and thereby potentiates spontaneous cell recruitment to demyelination lesions in the corpus callosum. Conversely, animals lacking Reelin signaling exhibit reduced endogenous progenitor recruitment at the lesion site. Altogether, these results demonstrate that beyond its known role during brain development, Reelin is a key player in post-lesional cell migration in the adult brain. Finally our findings provide proof of concept that allowing progenitors to escape from the RMS is a potential therapeutic approach to promote myelin repair.

MYADM regulates Rac1 targeting to ordered membranes required for cell spreading and migration

Membrane organization into condensed domains or rafts provides molecular platforms for selective recruitment of proteins. Cell migration is a general process that requires spatiotemporal targeting of Rac1 to membrane rafts. The protein machinery responsible for making rafts competent to recruit Rac1 remains elusive. Some members of the MAL family of proteins are involved in specialized processes dependent on this type of membrane. Because condensed membrane domains are a general feature of the plasma membrane of all mammalian cells, we hypothesized that MAL family members with ubiquitous expression and plasma membrane distribution could be involved in the organization of membranes for cell migration. We show that myeloid-associated differentiation marker (MYADM), a protein with unique features within the MAL family, colocalizes with Rac1 in membrane protrusions at the cell surface and distributes in condensed membranes. MYADM knockdown (KD) cells had altered membrane condensation and showed deficient incorporation of Rac1 to membrane raft fractions and, similar to Rac1 KD cells, exhibited reduced cell spreading and migration. Results of rescue-of-function experiments by expression of MYADM or active Rac1L61 in cells knocked down for Rac1 or MYADM, respectively, are consistent with the idea that MYADM and Rac1 act on parallel pathways that lead to similar functional outcomes.