Search results for " migration."

Phylogeography of a Habitat Specialist with High Dispersal Capability: The Savi’s Warbler Locustella luscinioides

2012

In order to describe the influence of Pleistocene glaciations on the genetic structure and demography of a highly mobile, but specialized, passerine, the Savi's Warbler (Locustella luscinioides), mitochondrial DNA sequences (ND2) and microsatellites were analysed in c.330 individuals of 17 breeding and two wintering populations. Phylogenetic, population genetics and coalescent methods were used to describe the genetic structure, determine the timing of the major splits and model the demography of populations. Savi's Warblers split from its sister species c.8 million years ago and have two major haplotype groups that diverged in the early/middle Pleistocene. One of these clades originated in…

Transnational Political Activities of the Swedish Finn Youth Organization

2017

This article looks at the Swedish Finn Youth Organization’s transnational political activities, and how they have developed. In the beginning, the youth organization modelled itself after its mother organization and joined the Finnish Expatriate Parliament (FEP), which made its participation in transnational practices easy. The case study of the Swedish Finn Youth Organization in Stockholm, Sweden, demonstrates that if the younger generation is given an opportunity to establish and govern their own associations, new forms of organization can be expected. The younger generation has distinguished itself from the older generation’s associations by cooperating with other minorities and taking m…

Migration and the Mediterranean: The EU’s Response to the “European Refugee Crisis”

2020

This chapter describes and examines the origin, nature and development of the so-called “European refugee crisis” and particularly analyzes the internal and external measures taken by the EU and its Member States in response to it. Our inquiry focuses on the following measures: (1) hotspots and emergency support for affected Member States, (2) relocation, (3) resettlement and other legal ways of entry, (4) the CEAS reform, (5) addressing irregular migration through border controls and countering smuggling and trafficking, (6) return and readmission, (7) the EU–Turkey Statement, (8) additional cooperation with third countries as well as (8) (trust) funds to support regions of origin and tran…

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…

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…

2020

Freely available healthcare, universally accessible to the population of citizens, is a key ideal for European welfare systems. As labor migration of the twentieth century gave way to the globalized streams of the twenty-first century, new challenges to fulfilling these ideals have emerged. The principle of freedom of movement, together with large-scale forced migration have led to large scale movements of people, making new demands on European healthcare systems which had previously been largely focused on meeting sedentary local populations' needs. Drawing on interviews with service providers working for NGOs and public healthcare systems and with policy makers across 10 European countrie…