Migration up and down the urban hierarchy and across the life course.

In this article, we begin by reviewing the concept of step migration that originated in E. G. Ravenstein's seminal papers "The Laws of Migration" (1885, 1889). As a result of the forces of the Industrial Revolution underway in 19th century Great Britain, migrants moved from farms to villages, from villages to towns, from towns to county seats, and thence to large cities. Throughout much of the industrialization era in the United States, net population movements similarly were upward within the urban hierarchy, and step migration today remains widespread throughout much of the still developing world. Our investigations of recent data and trends, however, suggest that the latest U.S. migration-pattern regime is a strongly contrasting one. Many of the major movements in the system of internal (or domestic) migration are flows down the urban hierarchy, although we note highly differentiated patterns for persons and households at specific stages of the life course. We make use of the newly defined metropolitan and micropolitan Core-Based Statistical Areas (CBSAs) and a seven-level size typology to tabulate origin-destination-specific migration flow data from both Census 2000 and IRS tax-return administrative records for the period 1995-2000. We discuss the causes for net movements being either upward or downward in the national urban hierarchy, including the effects of spatially focused immigration, and movement preferences at various ages, including migration in young adulthood associated with entering and leaving college and the military, as well as moves characteristic of the stages of family formation, childrearing, and retirement.

Geographical pattern analysis of income migration in the United States.

"How one conceptualises the impacts of migration depends on whether one takes the viewpoint of aggregate area-level income change, of per capita change, or of longer-term (future earnings) change. Several empirical analytical measures are proposed in order to conceptualise the various income impacts of migration.... [A] decomposition procedure is developed for examining how the changes in per capita income of states reflect three different income differentials: those between (a) in-migrants and 'stayers', (b) out-migrants and 'stayers', and (c) in-migrants and out-migrants. Examination of these measures, and of typologies based on them, highlights how income migration significantly and differentially impacts upon U.S. states. The methods are illustrated here in the context of an important new American data source: the 1993-94 migrant income data released by the U.S. Internal Revenue Service."

The dynamics of neighborhood age composition.

"In this paper we investigate the changing demography of [U.S.] neighborhoods. We focus upon the dynamics of the age structure of neighborhoods, paying particular attention to the roles of (a) the magnitude of mobility and (b) the age composition of in-migrants and out-migrants. A model for studying the changing age composition of neighborhoods is developed, and alternative scenarios characterized by the nature of in-movement and out-movement are examined to make statements about the age of householders in neighborhoods. We find that high rates of mobility may serve to bring about a relatively youthful equilibrium age structure quite rapidly, whereas low rates lead to a higher mean age and to damped harmonic fluctuations both in the mean age of householders and in the magnitude of the age heterogeneity of the neighborhood. In addition, we compare the evolutions of age structure in neighborhoods with age patterns of in-movement and out-movement that could typify areas of renters and areas of homeowners."

Measuring spatial focusing in a migration system.

Equality indexes used in other geographical contexts may be used to gauge the degree of spatial focusing in an entire migration system or within the gross in- and out-migration fields of specific regions. They provide useful indicators of overall shifts in the patterns of interregional migration and can help give insight into the population redistributive roles played by specific regions. Perhaps the most common equality index used to measure income distribution is the Gini coefficient, yet it appears almost never to have been applied in migration research. In this paper we set forth a variety of Gini indexes to be used for different migration analyses and illustrate their application with recent data on U.S. interstate movements. We argue that the Gini index provides some singularly useful insights that differ from those afforded by other measures more commonly found to date in the migration analyst's tool kit.

The role of migration research in regional science.

"In this paper we try to provide an assessment of the role that migration research has played over the course of the more than 40 years in which regional science has existed as a recognizable, multidisciplinary academic enterprise.... To carry out our analyses we developed a data base of papers published in five leading regional science journals." The authors "attempt to set the regional science contributions in the context of migration research more generally, comparing the results of the journal analysis to a broader sample of migration abstracts published in the Population Index."

Migration and the quasi-labor market in Russia.

"This paper explores the twin concepts of labor demand and labor mobility during the Soviet and post-Soviet periods. The study uses a detailed data set on labor stock, industrial labor demand, and labor flows for the 1980s in the Yaroslavl' Oblast, and data on migration and regional labor markets for all Russian regions in the 1990s. Contextual features, such as the social contract, full employment, methods of labor allocation, and a generally low rate of geographic mobility, distinguish the centrally planned quasi-labor market from the labor market in capitalist democracies. The findings suggest that net in-migration induces employment change in the current period rather than in a future period. The job creation effects appear concurrent with migration during the Soviet period. In the post-Soviet period, migration and employment relationships are not predictable based on the same relationships during the Soviet period."

The wax and wane of interstate migration patterns in the U.S.A. in the 1980s: a demographic effectiveness field perspective.

The author analyzes the structure of temporal changes in U.S. internal migration over the period 1980-1988 using data from matched income tax returns. "A number of hypotheses are explored about how in-migration and out-migration fields wax and wane, thereby giving rise to the overall shifts in demographic effectiveness measured over the period. The results highlight the characteristics of recent (1980-88) shifts in U.S. internal migration patterns including net migration reversals from strong net in-migration to strong net out-migration for states with significant energy sectors, the stanching of net out-migration from many states of the American manufacturing belt, the turnaround to net in-migration for all of northern New England, and the continuance of highly effective net in-migration to the sunbelt states of Florida, Arizona, and Nevada."

Demographic influences on migration.

"This paper explores the effects of demographic change on migration [within the United States] through an examination of migration rates of different age groups and cohorts over time, and the effect on total migration flows of the ageing of regional populations....[The author concludes that] the human investment framework provides a powerful analytical device for analysing migration decision-making at different stages of the life course. Labour supply pressure is advanced as a significant demographic influence on labour mobility." (SUMMARY IN FRE AND GER)

New directions in migration research: perspectives from some North American regional science disciplines.

"This paper takes several surveys of the literature concerning migration research as its starting point and directs the reader toward a number of potentially fruitful lines for future research. Major sections include one on modeling migrant choice in which the pros and cons of using gross versus net migration measures are discussed. A second introduces and discusses the concept of a 'spatial' choice set, which has the potential to be implemented with laboratory experimental techniques. The third involves a wide-ranging discussion of new directions in modeling the interrelationships between employment and migration." The primary geographical focus is on the United States.

Treatment of benign gastric ulcer: a comparative clinical trial of rioprostil and ranitidine.

This study is a multicentre, double-blind, double-dummy, two-way, parallel group comparison of the efficacy and safety of rioprostil and ranitidine in the treatment of active gastric ulcer. Ninety-one patients with gastric ulcer are randomly allocated to treatment with either rioprostil 300 micrograms b.d., or ranitidine, 150 mg b.d. The duration of treatment is 4 weeks, or 8 weeks for the patients who are improved but not healed at 4 weeks. Clinical, endoscopic and laboratory assessments are made before treatment, and after each treatment period. Therapeutic success is defined as complete endoscopic healing of the ulcer. At the end of the treatment period, either 4 or 8 weeks, healing rates are 69% in the rioprostil group, and 66% in the ranitidine group; this difference is not significant (p = 0.86). After the first 4 weeks of treatment the healing rates are 44% and 55% in the rioprostil and ranitidine groups, respectively. The incidence of adverse effects is 22% in the rioprostil group, and 7% in the ranitidine group (p = 0.036). Diarrhoea is the most common side effect (12%), but is usually intermittent and mild. We conclude that rioprostil, 300 micrograms b.d., for up to 8 weeks is as effective as ranitidine, 150 mg b.d., in the treatment of benign gastric ulcer.

Population migration and economic restructuring in the United States.

"This article demonstrates that sectoral employment shifts associated with the migration pattern changes of the 1970s are very different than those for the period 1955-60 to 1965-70. Changing competitiveness for jobs in manufacturing and other traditional basic sectors of the economy cannot account for the greatly accelerated levels of core-periphery net outflow that have been the dominant characteristic of interstate movement during the 1970s and 1980s. Instead, an interconnected set of activities that includes government, services, trade, and construction is associated with the broadscale shifts in the geographic pattern of the United States' population. The causal linkage from migration to employment change assumed heightened importance during the 1970s."

Dynamic flow modeling with interregional dependency effects: an application to structural change in the U.S. migration system.

Causative matrix methods can be used to project levels of population change, to monitor changing migration trends, and to aid in forecasting movement during periods of consolidation and dissipation. They are appealing because they provide measures of the changing strengths of all interregional dependency effects. Separate competing destinations and competing origins perspectives on temporal change can be obtained. The column sums and the eigenvalues provide useful aggregate gauges of the relative strengths of regional shifts. Patterns of U.S. interregional migration from 1935 to 1982 are examined using the causative matrix approach. Trends in the gross migration streams underlying the dramatic increase in core-periphery net migration taking place in the 1970s are examined, as is a more recent shift in the major source area of core region net outflow.

Forecasting interstate migration with limited data: a demographic-economic approach.

"The limitations of available migration data preclude a time-series approach of modeling interstate migration [in the United States]. The method presented here combines aspects of the demographic and economic approaches to forecasting migration in a manner compatible with existing data. Migration rates are modeled to change in response to changes in economic conditions. When applied to resently constructed data on migration based on income tax returns and then compared to standard demographic projections, the demographic-economic approach has a 20% lower total error in forecasting net migration by state for cohorts of labor-force age."

Economic-demographic models for forecasting interregional migration.

"A class of spatial economic-demographic forecasting models is proposed. The models combine elements of traditional Markov and economic gravity models. A base-period probability structure is modified by the changing relative distribution of economic opportunity. Estimation issues are addressed, and an empirical application to US interstate migration during the late 1970s is described. It is contended that the framework represents a merger of past demographic and economic modeling traditions in a spatial interaction framework."

A systematic demographic efficiency analysis of U.S. interstate population exchange, 1935-1980.

"Evolving patterns of population redistribution within the United States are examined for the period 1935 to 1980. The demographic efficiency measure is employed to assess the compensating or non-compensating nature of migration to and from each state. This measure is then extended in order to examine the entire system of state-to-state movement streams. Using the analytical technique of Q-analysis, systemic change is shown to have taken place. It is argued that the geographic pattern change reflects a nexus of economic and societal trends associated with post-industrialism."

[Veno-occlusive disease of the liver. Treatment by portocaval shunt]. / Maladie veino-occlusive du foie. Traitement par anastomose porto-cave.

A case of hepatic veno-occlusive disease revealed by abdominal pains and the rapid constitution of ascites in a 33-year old French female is reported. She had taken medicinal plants in order to loose weight. Liver biopsy showed typical histological changes consisting of centrizonal hemorrhagic necrosis and centrolobular vein obstruction with endophlebitis. Owing to an increase of ascites, a side-to-side portacaval shunt was performed. Eight months postoperatively, ascites had completely disappeared and the liver biopsy showed only a moderate centrolobular vein fibrosis. Five years later, the clinical state is normal.

An information theoretic approach to the estimation of migration flows.

PIP: This study is concerned with the application of different types of models to the study of migration flows. Two traditional approaches to migration modeling, the demographic fixed-rate and the gravity/entropy families of models, are first described, and their adequacy is assessed. The author next discusses the derivation of minimum information models. Consideration is given to destination-weighted models and to net-constrained models. A unified approach that incorporates both a priori micro and estimated macro parameters is then considered. The author concludes that the extended minimum information approach is the most suitable for building dynamic spatial interaction models, given the current state of U.S. internal migration data.^ieng

Estimation of place-to-place migration flows from net migration totals: a minimum information approach.

"A truism in demography has been that net migration may be derived from information on gross place-to-place flows, but that gross place-to-place flows cannot be inferred back from information on the net population movements in a system. Some recent work on maximum entropy and minimum information models, however, suggests a possible means for estimating just such as set of place-to-place flows. The net migration constrained model presented here could prove particularly useful for updating detailed migration matrices on the basis of current net migration estimates, and could even provide some clues as to the nature of the still poorly understood relationship between gross and net migration. Performance of the model is demonstrated using flow matrices from the 1960 and 1970 U.S. Censuses.

[Hypophosphatemia in total parenteral nutrition (author's transl)]. / Les hypophosphorémies de l'alimentation parentérale totale.

There is a hypophosphoremic syndrome first discovered without parenteral nutrition (TPN) then on patients with TPN. It appears preferentially in patients suffering from denutrition and receiving an important caloric intake, particularly with glucose. Clinical picture associates psychic, neurologic and respiratory disorders. Phosphatemia is often below 10 mg/l or 0,33 mmol/l, with decrease or even disappearance of phosphatemia. The mechanism is still baby known. During TPN, it occurs an intra-cellular passage of phosphate whose consequences are anomalies in red blood cell metabolism, with decrease of tissular oxygenation, in white cell function, platelet function, central nervous system, muscle, liver and acid-base equilibrium. Treatment must be first preventive with careful control of phosphatemia and systematic intake of phosphates. Curative treatment associates correction of hypophosphatemia and simultaneous decrease of caloric intake.