Search results for " Migration"

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…

Frontiera e retoriche della migrazione: il caso della carta di Palermo 2015

2019

Questo lavoro propone una riflessione da una prospettiva geografica sul concetto di frontiera e sulle forme di spazialità che esso implica. Più in particolare, gli autori si concentrano sulle modalità attraverso cui la frontiera è continuamente (ri)definita a partire dalle retoriche (soprattutto pubbliche e mediatiche) che accompagnano le migrazioni considerate “clandestine” secondo le attuali norme europee. Le riflessioni vengono sviluppate a partire dal caso studio dell’immigrazione irregolare a Palermo, attraverso l’analisi della Carta di Palermo 2015, un documento approvato dalla Giunta comunale del capoluogo siciliano nel 2015 (e, successivamente, inviato alle massime cariche dello Sta…

Effects of Emergence Time and Early Social Rearing Environment on Behaviour of Atlantic Salmon: Consequences for Juvenile Fitness and Smolt Migration

2015

Consistent individual differences in behaviour have been well documented in a variety of animal taxa, but surprisingly little is known about the fitness and life-history consequences of such individual variation. In wild salmonids, the timing of fry emergence from gravel spawning nests has been suggested to be coupled with individual behavioural traits. Here, we further investigate the link between timing of spawning nest emergence and behaviour of Atlantic salmon (Salmo salar), test effects of social rearing environment on behavioural traits in fish with different emergence times, and assess whether behavioural traits measured in the laboratory predict growth, survival, and migration statu…

Young neurons from medial ganglionic eminence disperse in adult and embryonic brain.

1999

In this study, we identified neuronal precursors that can disperse through adult mammalian brain tissue. Transplanted neuronal precursors from embryonic medial ganglionic eminence (MGE), but not from lateral ganglionic eminence (LGE) or neocortex, dispersed and differentiated into neurons in multiple adult brain regions. In contrast, only LGE cells were able to migrate efficiently from the adult subventricular zone to the olfactory bulb. In embryonic brain slices, MGE cells migrated extensively toward cortex. Our results demonstrate that cells in different germinal regions have unique migratory potentials, and that adult mammalian brain can support widespread dispersion of specific populati…

Support for Prostitution Legalization in Romania: Individual, Household, and Socio-cultural Determinants.

2021

Romania is a major source country of labor migration to other EU countries, being commonly perceived as a source country for sex workers operating in more prosperous economies. However, very little is known about population attitudes in relation to prostitution in Romania. Based on nationally representative data from the Romanian Gender Barometer (2018) survey, we analyzed data on 860 individuals to examine the predictors of policy preferences for legalizing prostitution. We considered individual-level socio-demographics and household-level indicators such as the presence of children and migrants, as well as socio-cultural beliefs and behaviors related to social liberalism and religiosity. …