Search results for "Migration"
showing 10 items of 1709 documents
Presentación del Monográfico: una mirada a la emigración española cualificada reciente: Estado de la cuestión y enfoques teóricos
2018
The study of qualified emigration has returned to the political and scientific agendas in recent decades. Currently the theoretical approaches have changed from a completely renewed economic, political, social and technological context. This article presents a summary of these new approaches and a current overview of skilled migration of Spaniards, based on a review of the specialized literature.
Disruption of Eph/ephrin signaling affects migration and proliferation in the adult subventricular zone.
2000
The subventricular zone (SVZ) of the lateral ventricles, the largest remaining germinal zone of the adult mammalian brain, contains an extensive network of neuroblasts migrating rostrally to the olfactory bulb. Little is known about the endogenous proliferation signals for SVZ neural stem cells or guidance cues along the migration pathway. Here we show that the receptor tyrosine kinases EphB1-3 and EphA4 and their transmembrane ligands, ephrins-B2/3, are expressed by cells of the SVZ. Electron microscopy revealed ephrin-B ligands associated with SVZ astrocytes, which function as stem cells in this germinal zone. A three-day infusion of the ectodomain of either EphB2 or ephrin-B2 into the la…
Integrins α5β1, αvβ1, and αvβ6 Collaborate in Squamous Carcinoma Cell Spreading and Migration on Fibronectin
2000
Abstract The expression of αvβ6 fibronectin/tenascin receptor integrin is induced in malignant transformation of oral epithelium. In this study, we demonstrate the contribution of αvβ6 as well as other fibronectin receptor integrins in squamous cell carcinoma (SCC) cell adhesion and migration. Of 11 SCC cell lines isolated from the head and neck area, 8 (73%) expressed αvβ6 integrin on the cell surface. Three cell lines were chosen for further functional experiments: 1 with relatively high, 1 with moderate, and 1 with minimal surface expression of αvβ6 integrin. In addition to αvβ6, all 3 cell lines expressed α5β1 and αvβ1 fibronectin receptor integrins. Function-blocking experiments with i…
Homeward Bound FDI: Are Migrants a Bridge over Trouble Finance?
2016
Migrants can lower cross-border investment barriers, help investors by providing information about their homeland and reduce transaction costs by sharing expertise on regulations, customs and procedures. In addition to generating these well-known networking effects, migrants can also provide valuable information about local finance, thereby easing the credit constraints foreign investors faced during the 2007 financial crisis. This paper sheds new light on the underlying mechanisms through which migration may affect foreign investment in the migrant's homeland by distinguishing between the effects on FDI's intensive and extensive margins. Gravity estimates for 140 countries for the period 2…
Emotion Regulation and Identity Negotiation: A Short Story Analysis of Finnish Language Teachers’ Emotional Experiences Teaching Pupils of Immigrant …
2021
This study explores the connection between emotion regulation and teacher identity by drawing on short stories present in interviews with four Finnish language teachers working with immigrant pupil...
Use of stable isotope analysis to evaluate the possible impact of fish migration on a lake biomanipulation
2007
1. A lake restoration project involving mass fish removals was started to improve further the water quality of a lake recovering from severe eutrophication. The effectiveness of such biomanipulation as a lake management option could be compromised if removed fish are rapidly replaced by large-scale immigration from a connected lake. 2. Stable isotope analysis (SIA) was used to examine the migrations of perch (Perca fluviatilis L.) and roach (Rutilus rutilus (L.)) between two connected lakes in central Finland, Jyvasjarvi and the larger Paijanne. Baseline δ15N signatures in primary consumers were significantly higher in Jyvasjarvi and this difference was reflected further up the food chain i…
La remontée du saumon pour le frai dans le fleuve Tornionjoki, suivie au moyen d'un sonar à double faisceau horizontal.
2000
Fixed location split-beam horizontal echosounding was used to assess the size and timing of the Atlantic salmon (Salmo salar) spawning run in the River Tornionjoki. Four transducers, two on each river bank, were mounted across the river at the study site 4 km upstream from the river mouth. Net weirs were used on both shores to direct the passage of fish through the acoustic beams. Hydroacoustic monitoring covered 40-50% of the river cross-sectional area. Also test fishing and yearly catch statistics of salmon were used as an indication of the size of the spawning run in the river. Altogether, 7 700, 5 300 and 4 300 salmon-sized targets (target strength, TS ≥ -29 dB) moving upstream were det…
Experimental analysis of the effect of vegetation on flow and bed shear stress distribution in high-curvature bends
2016
The cross-sectional circulation, which develops in meandering bends, exerts an important role in velocity and the boundary shear stress redistributions. This paper considers the effect of vegetation on cross-sectional flow and bed shear distribution along a high-curvature bend. The analysis is conducted with the aid of data collected in a large-amplitude meandering flume during a reference experiment without vegetation and an experiment with vegetation on the bed. The results show that the presence of vegetation modifies the curvature-induced flow pattern and the directionality of turbulent structures. In fact, in the presence of vegetation, the turbulent structures tend to develop within a…
Safety Assessment and Migration Tests
2018
This chapter outlines (i) the advances to reduce the uncertainty in nanomaterials (NMs) determination; (ii) the results from migration experiments conducted with nano-clay, nanosilver, and other nanomaterial-containing polymers; and (iii) the different established protocols for risk assessment that ensure consumer's safety. The text starts highlighting the need of an understanding of potential exposure via migration into food and a deeper knowledge of the interaction of NMs with food constituents and their effects upon ingestion. The chapter covers the ability of the analytical techniques utilized to detect nanoparticles per se in food simulants. In addition, the results of the application …
The consequences of physical post-treatments (microwave and electron-beam) on food/packaging interactions: A physicochemical and toxicological approa…
2016
IF 4.052; The safety of microwave and electron-beam treatments has been demonstrated, in regards to the formation of reaction products that could endanger human health. An integrated approach was used combining the potential toxicity of all the substances likely to migrate to their chemical characterizations. This approach was applied to polypropylene (PP) films prepared with a selection of additives. Components were identified by liquid and gas chromatography using a mass selective detector system. Their potential toxicity was assessed using three in vitro short-term bioassays and their migrations were carried out using a standards-based approach. After the electron-beam treatment some add…