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Biomedical subjects

J Ledent

Publications and source records attributed to J Ledent.

17 recordsLinked to original sources
PubMed1995

[Toward a projection of families according to their principal characteristics].

"This article describes the main ingredients of a methodology currently under development for projecting families [in Canada]--these groups of individuals linked by conjugal ties or by blood--according to their principal characteristics: family type and number/ages of children. The crux of this methodology is a multidimensional model which can be viewed as an extension of the traditional cohort-components model that incorporates the conjugal and parity statuses of women. With an appropriate generalization of the conjugal status variable and the addition of an appendage for dealing with the special case of step families, this model eventually allows one to shift from the number of women according to demographic status (stemming from cross-classifying conjugal status and numbers of children present) to those families according to their main characteristics." (SUMMARY IN ENG AND SPA)

Adolescent↗
PubMed1989

Provincial out-migration patterns of Canadian elderly: characterization and explanation.

"Interprovincial migration patterns of Canada's elderly are examined and compared with their nonelderly counterparts, by using data from Revenue Canada's income tax file for a fifteen-year period (1966/67-1980/81)." The results indicate that departure rates and patterns of destination choice are broadly similar for both groups, although "destination choice of the elderly was relatively sensitive...to environmental factors, whereas that of the nonelderly was relatively sensitive to labor-market variables...."

Adult↗
PubMed1988

Stable growth in native-dependent multistate population dynamics.

"Users of multistate life tables and projections have recognized that the Markovian assumptions underlying such models are unduly restrictive and should be relaxed whenever data permit. Efforts to include the influences of previous occupancies have included the incorporation of place-of-birth dependence. This paper addresses the stable growth properties of such generalized multistate models. It shows how place-of-birth-specific stable growth measures can be calculated without projection simply by solving the characteristic equation. An example using Canadian data illustrates the argument." (SUMMARY IN FRE)

Americas↗
PubMed1988

Joint effects of ecological and personal factors on elderly interprovincial migration in Canada.

"This paper analyzes the joint effects of ecological and personal factors on elderly migration in Canada in the late 1970s, using information on migration and personal factors extracted from the individual file of the 1981 Public Use Sample. Our focus on elderly Canadians stems from the expectation that the Canadian population will continue to age rapidly over the next three decades and that the elderly's demand for services (for example, health care and income maintenance) will expand rapidly as a consequence. Some of these services are clearly location-specific and should be matched to the changing distribution of the elderly population, which is, of course, affected by geographic mobility." (SUMMARY IN FRE)

Adult↗
PubMed1987

Nested logit model and maximum quasi-likelihood method: a flexible methodology for analyzing interregional migration patterns.

"A flexible methodology for explaining interregional migration in terms of relevant socioeconomic variables is set forth in this paper. Concerned with setting observation against theory, it makes use of (1) the nested logit model as a theoretical substratum, and (2) the maximum quasi-likelihood method as a method for parameter estimation and statistical inference. Application to interprovincial migration data over a 22-year period (1961-1962 to 1982-1983) shows that, in Canada, migration does not appear to serve well as an equalizer of economic opportunities."

Americas↗
PubMed1986

A model of urbanization with nonlinear migration flows.

"This paper seeks an appropriate specification of the migration exchange between rural and urban areas so that the implied evolution of the degree of urbanization agrees with its commonly observed S-shape. After demonstrating that the gross migration flows between rural and urban areas should be specified as nonlinear functions of the population in the origin sector, the paper introduces a model in which such flows are represented by gravity-type functional forms....[The model] can be used to give insights into the time paths of three basic urbanization variables: the urban-rural growth rate differential, the rural net outmigration rate, and the urban net immigration rate. All take on a zero value at the two extremes of the urbanization process and evolve in between according to a bell-shaped curve. These findings are illustrated by applying the model to data from the United States for the period 1790-1980."

Americas↗
PubMed1984

[Multidimensional mathematical demography: a survey].

The development of multidimensional mathematical demography and its application to the analysis of such changes in life status as marriage, occupation, and migration is discussed. "This article presents an overview of the methods and models specific to this new branch. It stresses (1) their relationship with the methods and models of classical mathematical demography, (2) their field of application, (3) their elaboration, and (4) a few methodological and empirical questions raised by their use." (summary in ENG, SPA)

Demography↗
PubMed1983

Migration and settlement: a multiregional comparative study.

"In 1976, the International Institute for Applied Systems Analysis initiated a study of migration and population distribution patterns in its seventeen member nations. In each country, the analysis was carried out by national scholars using techniques of multiregional demography. In this paper the authors describe the organization of the study, discuss the data bases used, evaluate the main results obtained, and review some of the methodological research that has been generated by the study. Among the...conclusions are recommendations for researchers wishing to carry out a multiregional demographic analysis." Consideration is given to national and subnational patterns of mortality, fertility, and migration; age composition; and regional population distribution.

Age Distribution↗
PubMed1983

[The dynamics of multi-regional demographic systems--the case of a nonlinear migration model].

"To provide new insight into the evolution of multiregional population systems, this article presents a dynamic study of a nonlinear variant of the components-of-change model. In this variant, migrants out of a region do not distribute themselves among destination regions in constant proportions (as in the classical linear variant). Rather their allocation is proportional to that of population (weighted so as to account for the difficulty to move between regions). The analysis focuses on the existence, characteristics, and determination of equilibrium states. It is illustrated with an application to the population of Canada and its five large regions." (summary in ENG)

Americas↗
PubMed1983

[A log-linear analysis of interprovincial migratory flows: Canada, 1961-1983].

"This article presents an in-depth analysis of spatial-temporal characteristics of interprovincial migration in Canada carried out with longitudinal data obtained from the family allowance file. The methodology used calls on the log-linear model underlying the notion of the contingency table. This model permits a simple representation of the observed data, with the aid of parameters typical of the many possible interactions between the variables in question (variables of origin, destination and period in the present case)." The relative influence of the selected variables on migration is first assessed. "Second, this influence is further specified with the aid of a detailed investigation of the parameters that are relative to the quasi-independence variance, that is to say, the variance where only the effect of interaction between the three variables is ignored. Together with the suggestion that the variables of origin and destination are not independent (a result that confirms the need to emphasize interregional streams in the study of migration), this investigation sets forth some conclusions about the temporal variations of interprovincial migration." (summary in ENG, SPA)

Americas↗
PubMed1982

The factors of urban population growth: net inmigration versus natural increase.

"As a country evolves from a traditional to an advanced society, the part of urban growth that is due to net inmigration follows a simple pattern, which can be described by an inverted U-shaped curve: it first increases, then passes through a maximum, and decreases thereafter. This hypothesis is confirmed by quantitative analysis using time-series and cross-section data. The analysis suggests that in the second half of this century natural increase often provides a slightly higher contribution to urban population growth than net inmigration." (summary in FRE, ITA, JPN, )

Demography↗
PubMed1981

A framework for modeling interregional population distribution and economic growth.

"An integrated model is proposed to capture economic and demographic interactions in a system of regions. This model links the interregional economic model of Isard (1960) and the interregional demographic model of Rogers (1975) via functions describing consumption and migration patterns. Migration rates are determined jointly with labor force participation rates and unemployment rates."

Demography↗