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At least 613 records · Page 34Linked to original sources
PubMed1997

[Big-city migration in historical perspective].

"The migration flows to and from the four largest Dutch municipalities (Amsterdam, Rotterdam, The Hague and Utrecht) show a number of similarities. During the past few decades internal migration has been characterized by a move away from the large cities, while the much smaller international migration flow had an opposite direction. This has resulted in a net decrease of the total population in the largest cities." (SUMMARY IN ENG)

Demography↗
PubMed1992

[Demographic behavior of linguistic groups in Montreal].

The author examines trends in fertility, internal migration, and mortality among the principal linguistic groups in Montreal, Canada. "Certain non-negligible disparities exist in demographic behaviour of linguistic groups on the Montreal and Jesus Islands. On the other hand, in the rest of the metropolitan Montreal area, linguistic disparities in demographic behaviour are noticeably smaller: the three groups have the same fertility level and the same propensity to migrate; only differentials in mortality can be observed. The natural growth rate of francophones on the Island of Montreal was (in 1985-1987) slightly inferior to that of the other two groups, but in the metropolitan region it was superior. On the whole however, taking into account internal migration, the group of francophones of the Islands of Montreal and Jesus had the highest growth rate and the anglophone group the lowest rate (in fact negative)." (SUMMARY IN ENG AND SPA)

Americas↗
PubMed1988

Urbanization, the informal sector and migration: issues for research and cooperation.

Only recently have development studies begun to examine the complex set of relationships between urbanization, the growth of the informal sector, and internal migration in Latin America. This paper suggests that the economic crisis of the 1980s has resulted in significant changes in these phenomena and that 1 of the most important changes has been the growth of return international migration between Latin American countries. Also of importance are the continued migration flows to North America. The paper argues that the interconnectedness of these phenomena requires more multinational research efforts.

Americas↗
PubMed1988

Recent trends in migration between core and peripheral regions in developed and advanced developing countries.

"The main finding of this article is that net internal migration to the core regions in the countries of the developed world, which subsided in the 1970s, increased in the 1980s, although not to the level of the 1960s. In some countries of northwest Europe there is a balance now in net flows between core and periphery. In the countries of the periphery of Europe and Japan net internal migration to the core regions increased slightly in the 1980s. Net migration flows to the periphery have completely reversed in Canada, and net flows out of the core regions of the United States have been significantly reduced. In eastern Europe, however, there is still moderate net migration to the core regions without any interruption as seen in western Europe, North America, and Japan. In South Korea and Taiwan rates of net migration to the core regions have been reduced from their high levels of the 1970s, but they are still quite high and show no clear sign of a break from the past."

Asia↗
PubMed2002

Registration accuracy and possible migration of internal fiducial gold marker implanted in prostate and liver treated with real-time tumor-tracking radiation therapy (RTRT).

BACKGROUND AND PURPOSE: We have developed a linear accelerator synchronized with a fluoroscopic real-time tumor-tracking system to reduce errors due to setup and organ motion. In the real-time tumor-tracking radiation therapy (RTRT) system, the accuracy of tumor tracking depends on the registration of the marker's coordinates. The registration accuracy and possible migration of the internal fiducial gold marker implanted into prostate and liver was investigated. MATERIALS AND METHODS: Internal fiducial gold markers were implanted in 14 patients with prostate cancer and four patients with liver tumors. Computed tomography (CT) was carried out as a part of treatment planning in the 18 patients. A total of 72 follow-up CT scans were taken. We calculated the relative relationship between the coordinates of the center of mass (CM) of the organs and those of the marker. The discrepancy in the CM coordinates during a follow-up CT compared to those recorded during the planning CT was used to study possible marker migration. RESULTS: The standard deviation (SD) of interobserver variations in the CM coordinates was within 2.0 and 0.4 mm for the organ and the marker, respectively, in seven observers. Assuming that organs do not shrink, grow, or rotate, the maximum SD of migration error in each direction was estimated to be less than 2.5 and 2.0 mm for liver and prostate, respectively. There was no correlation between the marker position and the time after implantation. CONCLUSION: The degree of possible migration of the internal fiducial marker was within the limits of accuracy of the CT measurement. Most of the marker movement can be attributed to the measurement uncertainty, which also influences registration in actual treatment planning. Thus, even with the gold marker and RTRT system, a planning target volume margin should be used to account for registration uncertainty.

Carcinoma, Hepatocellular↗
PubMed1983

Co-migration and internalization of transferrin and its receptor on K562 cells.

The incorporation of iron into human cells involves the binding of diferric transferrin to a specific cell surface receptor. We studied the process of endocytosis in K562, a human erythroid cell line, by using tetramethylrhodamine isothiocyanate-labeled transferrin (TRITC-transferrin) and fluorescein isothiocyanate-labeled Fab fragments of goat antireceptor IgG preparation (FITC-Fab-antitransferrin receptor antibody). Because the antireceptor antibody and transferrin bind to different sites on the transferrin receptor molecule it was possible to simultaneously and independently follow ligand and receptor. At 4 degrees C, the binding of TRITC-transferrin or FITC-Fab antitransferrin receptor antibody exhibited diffuse membrane fluorescence. At 20 degrees C, the binding of TRITC-transferrin was followed by the rapid formation of aggregates. However, the FITC-Fab antitransferrin receptor did not show similar aggregation at 20 degrees C unless transferrin was present. In the presence of transferrin, the FITC-Fab antitransferrin receptor antibody formed aggregates at the same sites and within the same time period as TRITC transferrin, indicating co-migration. Although the diffuse surface staining of either label was removed by proteolysis, the larger aggregates were not susceptible to enzyme degradation, indicating that they were intracellular. The internal location of the aggregates was also demonstrated using permeabilized cells that had been preincubated with transferrin and fixed with 4% paraformaldehyde. These cells showed aggregated receptor in the interior of the cell when reacted with fluorescein-labeled antibody to the receptor. This indicated that the transferrin and the transferrin receptor co-internalize and migrate to the same structures within the cell.

Cell Line↗
PubMed1994

Re-thinking skilled international labour migration: world cities and banking organisations.

"Highly skilled professional and managerial labour migration has become an important facet of the contemporary world economy. The operations of transnational corporations have created more opportunities for skilled migrants to work abroad.... There is a growing interest amongst economic geographers to examine this form of migration through an appreciation of global economic restructuring, labour market change and world cities. Consequently, this paper introduces a new conceptual framework...[which] is based on the rationale that world cities, and the patterns of labour market demand that exist within them, are of paramount importance in influencing highly skilled professional and managerial labour migration within the world economy. The author uses an example of highly skilled labour migration within the transnational banking sector [in London] to illustrate this new conceptual framework."

Demography↗