The effects of immigration on U.S. wages and rents: a general equilibrium approach

In this paper we document a strong positive correlation of immigration flows with changes in average wages and average house rents for native residents across U.S. states. Instrumental variables estimates reveal that the correlations are compatible with a causal interpretation from immigration to wages and rents of natives. Separating the effects of immigrants on natives of different schooling levels we find positive effects on the wages and rents of highly educated and small effects on the wages (negative) and rents (positive) of less educated. We propose a model where natives and immigrants of three different education levels interact in production in a central district and live in the surrounding region. In equilibrium the inflow of immigrants has a positive productive effect on natives due to complementarities in production as well as a positive competition effect on rents. The model calibrated and simulated with U.S.-states data matches most of the estimated effects of immigrants on wages and rents of natives in the period 1990-2005. This validation suggests the proposed model as a useful tool to evaluate the impacts of alternative immigration scenarios on U.S. wages and rents

Agglomeration in a global Economy: A Survey

This review of recent contributions reveals common conclusions about the effects of integration on location. For high trade costs, the need to supply markets locally encourages firms to spread across different regions. Integration weakens the incentives for self-sufficiency and for intermediate values of trade costs pecuniary externalities induce firms and workers to cluster together, turning location into a self-reinforcing process. However, agglomeration raises the price of immobile local factors and goods, so far low transport costs firms may spread to regions where those prices are lower.

The labor market impact of immigration in Western Germany in the 1990’s

In this article we measure the effects of recent immigration on the Western German labor market looking at both wage and employment effects. Refining administrative data for the period 1987-2001 to account for ethnic German immigrants and immigrants from Eastern Germany, we find that the substantial immigration of the 1990’s had very little adverse effects on native wages and on their employment levels. Instead, it had a sizable adverse employment effect as well as a small adverse wage effect on previous waves of immigrants. These asymmetric results are partly driven by a higher degree of substitution between old and new immigrants in the labor market. In a simple calculation we show that the largest aggregate effect of new immigration on natives and old immigrants comes from the increased costs of unemployment benefits to old immigrants. Those costs could be eliminated in a world of wage flexibility and no unemployment insurance in which immigration would not have any negative employment effect but only moderate wage effects

Outsorcing, complementary innovations and growth

this papers studies the parallel creation of complementary upstream and downstream innovations by independent labs to sheld light on the impact of outsourced on R&D when supply contracts are incomplete. In particular, we argue tha outsourced upstream producion contributes to the emergence of innovation networks by creating a demand for upstream R&D. We then analyze under which conditions this leads to faster innovation thaan in the case of vertically integrated production relying on integraed R&D. In the presence of incomplete supply contracts, the ex-post bargaining power of upstream and downstream parties feed back to innovation. this determines whether outsourcing decisions leading to static gains from specialized production generate or not also dynamic gains in terms of faster innovation

Global Value Chains during the Great Trade Collapse: A Bullwhip Effect?

This paper analyzes the performance of global value chains during the trade collapse. To do so, it exploits a unique transaction-level dataset on French firms containing information on cross-border monthly transactions matched with data on worldwide intra-firm linkages as defined by property rights (multinational business groups, hierarchies of firms). This newly assembled dataset allows us to distinguish firm-level transactions among two alternative organizational modes of global value chains: internalization of activities (intra-group trade/trade among related parties) or establishment of supply contracts (arm’s length trade/trade among unrelated parties). After an overall assessment of the role of global value chains during the trade collapse, we document that intra-group trade in intermediates was characterized by a faster drop followed by a faster recovery than arm’s length trade. Amplified fluctuations in terms of trade elasticities by value chains have been referred to as the "bullwhip effect" and have been attributed to the adjustment of inventories within supply chains. In this paper we first confirm the existence of such an effect due to trade in intermediates, and we underline the role that different organizational modes can play in driving this adjustment.trade collapse, multinational firms, global value chains, hierarchies of firms, vertical integration.

Magneto-optical characterization of MnxGe1-x alloys obtained by ion implantation

Magneto-optical Kerr effect hysteresis loops at various wavelengths in the visible/near-infrared range have been used to characterize the magnetic properties of alloys obtained by implanting Mn ions at fixed energy in a Ge matrix. The details of the hysteresis loops reveal the presence of multiple magnetic contributions. They may be attributed to the inhomogeneous distribution of the magnetic atoms and, in particular, to the known coexistence of diluted Mn in the Ge matrix and metallic Mn-rich nanoparticles embedded in it [Phys. Rev. B 73, 195207(2006)].Comment: 2 pages, 2 figures. Proceeding of the International Conference on Magnetism. Kyoto, August 20-25 200

Relationship Between Nasal Cycle, Nasal Symptoms and Nasal Cytology

Background: The nasal cycle is the spontaneous congestion and decongestion of nasal mucosa that happens during the day. Classically, 4 types of nasal cycle patterns have been described: (1) classic, (2) parallel, (3) irregular, and (4) acyclic. Hypothalamus has been considered as the central regulator even if several external factors may influence its activity. Objective: The aim of the study was to evaluate the presence of a correlation between nasal cycle pattern, nasal cytology and nasal symptoms. Methods: Thirty healthy volunteers have been enrolled in the study. All subjects completed a Sino-Nasal Outcome Test-22 questionnaire and a Visual Analog Scale (VAS) for nasal obstruction. The nasal cycle was studied by means of peak nasal inspiratory flow. Nasal cytology has been used to evaluate the presence of local nasal inflammation. Results: Nineteen subjects showed a parallel nasal cycle pattern, while 11 showed a regular one. A parallel pattern was present in 60% of asymptomatic subjects and in 67% of the symptomatic one (P = 1). VAS for nasal obstruction did not show a significant difference between the 2 patterns of the nasal cycle (P =.398). Seventeen subjects had a normal rhinocytogram, while 13 volunteers showed a neutrophilic rhinitis; 53.8% of the subjects with a neutrophilic rhinitis showed a parallel pattern, while the remaining 46.2% had a regular one. In the case of a normal cytology, 70.6% of the volunteers had a parallel pattern and 29.4% had a regular one. Differences between the 2 groups were not statistically significant (P =.575). Conclusion: Rhinitis with neutrophils seems to not influence the nasal cycle pattern. Based on the present results, the pattern of nasal cycle does not influence subjective nasal obstruction sensation