Determining the initial age distribution for an age structured population

"This paper deals with an inverse problem in age-structured population dynamics; the recovery of an unknown initial age distribution. We attempt to recover this function from overposed data which consists of either the total population over a time interval equal to the maximum life span of the species or the age structure of the population at a fixed later time. Existence, uniqueness and continuous dependence of the initial distribution function on the data are addressed. Some numerical simulations are presented to illustrate the feasibility of recovery using the methods of the paper."     

Summary indices of the age distribution of a population

In this paper a method for characterizing the age distribution of a population by means of an ‘index word’ is outlined. It is shown that the method can be applied to yield approximations to population forecasts.     

On the relationship between household composition and population age distribution

Summary Composition of households by age of head and by age of other household members has recently been presented in a convenient algebraic expression, the household composition matrix. It has been shown that this matrix operates as a linear transformation from the vector of household distribution by age of head to the vector of population age distribution. A further analysis will show that the first row of the matrix may be interpreted as representing a vector of average household fertility rates. If the linear relationship between household and population distributions is fully implemented, then a relationship between household fertility and the size of the youngest age group can be derived. If w is the population age distribution and w (1) is the number of persons in the youngest age group, then: where α is the first row of the household composition matrix with its first element eliminated, C is the household composition matrix with its first row and first column eliminated, and Ψ is the vector w with its first element, w (1) eliminated. Extension of this result will enable simultaneous projection of population and households, suitable for computer application to conventional five-year age groups.     

On age distribution of population,government expenditure and fiscal federalism

In this paper I build a simple model to analyze the consequences that population growth imposes on the relative needs of expenditure of governments in a fiscal federalism setup. I assume, first, that some government expenditure items can be classified according to the age of their recipient individuals and, second, that different levels of government are usually assigned different expenditure programs. The implication is that, for an initially given level of effective public good provision, changes in the size of population as well as in its age structure will influence the composition of public expenditure for different layers of administration in a different manner.I would like to thank Jordi Caballé, Ángel de la Fuente, Javier Gardeazabal, Federico Grafe, Juan Urrutia and Jesús Vázquez for their valuable comments and suggestions. Two anonymous referees helped improve the initial version. Remaining errors and shortcomings are my own responsibility. Financial support from UPV 035.321-HA090/92 and UPV 035.321-HA130/93 is gratefully acknowledged.     

The age distribution of an industrial group (Scottish Railwaymen)

The age structure of the workers in an old-established industry, and the problems which might arise from it, formed the subject of the investigation. It was found that the group was atypical in that, in addition to having a higher average age than that of the total working population of Scotland, the age distribution was bimodal, with a marked excess in the S o + and a marked deficiency in the 3 5-44 age group. The bimodality was due to high recruitment after the first world war, followed by a low one a few years later. The bimodality was especially marked among footplatemen.

On the basis of age structure it is very difficult to identify grades to which older workers might be transferred. Certain receiving grades which " accommodate " the less healthy (and potentially also the older workers) were found to be relatively small in size compared with the operating grades, footplatemen or signalmen.

Projections were made to explore some of the repercussions of converting the age structure of a bimodal distribution to a standard, the working population of Scotland. There were three assumptions on total size : maintaining the size, a slow fall to 70% and a rapid fall to 70%. Within each of these there were three assumptions on sickness absence, drawn from experience of Scottish railwaymen and particularly footplatemen. These effects are described in the paper. They are not policy recommendations of what should happen ; they are indications of what might happen in certain circumstances. In a bimodal distribution it is easy to effect a reduction in total numbers by a reduction in recruitment, but the consequential longer term fluctuations in numbers are substantial and in sickness absence more so.

Those concerned with problems arising from recruitment, redundancy and age structures of working populations could get useful information by using appropriately realistic assumptions.     

Asymptotic properties of a human age distribution under a continuous net maternity function

A useful and intuitively appealing proposition in theoretical demography asserts that the age distribution of a closed human populationis asymptotically independent of this shapein thedistant past, and is therefore exclusively determined by the historyof fertility and mortalitythat has prevailed during a reasonably long period of time. The mathematical foundations of this ergodic principle arelaid out in this article and thedetailsof its proofareworked out afteremphasizing an intuitive understanding of the process through which an age distribution tends to "forget" its past. The tendency for an unchanging schedule of vital ratesto produce a fixed agestructure in a closed population, is presented as a corollary of the main proposition dealt with in this article.     

An Examination of the Heterosexism Scale

Researchers explored the factor structure of Park’s Heterosexism Scale (2001) with heterosexual parents of lesbian, gay, or bisexual sons or daughters. Results suggested a two-factor solution, but results varied from Park’s two-factor model. Additionally, relations between the Heterosexism Scale subscales and measures of cognitive flexibility, religious commitment, and general family functioning were examined. Implications for clinical practice and future research are discussed.     

A generalization of life expectancy which incorporates the age distribution of the population and its use in the measurement of the impact of mortality reduction

Two new families of indices measuring the gain in life expectancy resulting from reduction in mortality are introduced: the first looks at the impact of cause of death reduction from the perspective of the entire population; the second, at that segment of the population due to die of the cause. Special cases include both well-established measures and extensions that incorporate the age distribution of the population. A further generalization is introduced with the consideration of life expectancies that only give weight to years of life up to age 70. A number of inequalities are derived that relate cause-deleted life expectancies to their cause-reduced counterparts.     

Neoclassical growth with endogenous age distribution. Poverty vs low-fertility traps as steady states of demographic transitions

Compared to other factors, the role of the age distribution of the population as a key endogenous determinant of economic growth trajectories has traditionally been overlooked. This is unrealistic, especially when dealing with major epochs of structural change, such as demographic transitions. We set up a model combining a simple representation of the economy, based on the neoclassical growth model of Solow, with a comprehensive representation of population dynamics. The model is used to investigate the structure of balanced growth states of the population and the economy in the presence of demographic transitions. The analysis shows that proper inclusion of age structure enriches the spectrum of the long-run equilibria of the neoclassical model, allowing up to five states of balanced growth, and shows the onset of “poverty” and “low-fertility” traps as different facets of fertility transitions. The role of different timing of fertility, mortality and savings transitions, and of more realistic demography of capital, is also considered.     

A Critical Examination of the Environmental Mastery Scale

The Psychological well being Inventory (PWBI) is a multidimensional instrument that has enjoyed widespread use in a variety of research initiatives, from small-scale studies to national surveys. Recent empirical investigation of the measure has raised questions about its validity. This study examines the factorial validity of the Environmental Mastery Scale of the PWBI, a construct that receives much attention in mental health research. The results of a confirmatory factor analysis did not support the unidimensional factor structure of the measure. Correlated uniqueness models were also examined, which did not reveal evidence of a method effect. There are problems with the measure at the item level, which also raises significant questions about the underlying theory of its parent measure. This research uses data from the Wisconsin Longitudinal Study (WLS) of the University of Wisconsin-Madison. Since 1991, the WLS has been supported principally by the National Institute on Aging (AG-9775 and AG-21079), with additional support from the Vilas Estate Trust, the National Science Foundation, the Spencer Foundation, and the Graduate School of the University of Wisconsin-Madison. A public use file of data from the Wisconsin Longitudinal Study is available from the Wisconsin Longitudinal Study, University of Wisconsin-Madison, 1180 Observatory Drive, Madison, Wisconsin 53706 and at http://www.ssc.wisc.edu/wls/data/. The opinions expressed herein are those of the authors.     

A generalized index of dissimilarity

The index of dissimilarity can be interpreted as the ratio of the number that must be moved from cells of excess to cells of deficit to achieve even distribution. This interpretation is used to generalize the index in two directions. First, the index is made applicable to more than two groups at a time. Second, an index and a test of significance are made available for explorations of cells of a two-way contingency table. DISSIM is the name of a computer program which provides these calculations for contingency tables.     

Examination of the status of health of population in Poland

"This article presents sources of information about the health status of the Polish population...; the number and causes of deaths, the morbidity due to more important diseases and average life expectancy.... At the same time this situation is compared with those in some European countries."     

Old age and the demographic transition

Summary This paper examines the impact of the demographic transition upon the potential supply of, and demand for, family support for the aged in Australia. Using census and survey information on population cohorts entering old age, comparisons are drawn concerning their surviving issue, household composition and family membership. Long-term changes in fertility are shown to have had only a small impact upon the supply of potential carers among relatives and, although the demographic transition has led to a more universal inclusion of old people in family networks, there have not been major changes through time in the proportions living in extended family households. Short-term changes, however, such as low fertility during the 1930s, have caused disordered cohort flow, with the result that current generations of the elderly are members of deprived cohorts in terms of their access to family support.     

Simple bounds for the dominant eigenvalue of a generalized Leslie matrix

"Simple bounds are presented for the dominant eigenvalue of the generalized Leslie matrix of a multiregional demographic growth model." (SUMMARY IN FRE)     

取消强制婚检:是因噎废食,还是社会进步

背　景为了适应社会的迅速发展和巨大变化,2 0 0 1年4月2 8日第九届全国人民代表大会常务委员会第二十一次会议讨论通过了《关于修改〈中华人民共和国婚姻法〉的决定》,对婚姻法进行了修订,形成了我国现行的婚姻法律。为了配合婚姻法的修订,进一步完善婚姻登记工作,紧随其后,政府有关职能部门在2 0 0 3年颁发了新的《婚姻登记条例》(从2 0 0 3年1 0月1日起施行)。新《条例》在体现了政府公共管理和公共服务一些新的理念及政府职能转变趋势的同时,由于直接涉及到社会大众的切身利益,也在社会上引起了广泛的关注和巨大的反响。其中倍受瞩目的…     

Meta-analysis of the impact of age structure on fertility

The paper uses a meta-analysis to comparatively evaluate the literature addressing the aggregate relationship between a populations age structure and fertility, as hypothesized by Richard Easterlin. The analysis is based on 334 estimated effects retrieved from 19 studies. The results suggest that several factors undermine the empirical support of the Easterlinian age structure/fertility link. These include the neglect of income, the use of relative cohort size to characterize the age structure, mis-specifications of the relevant age-cohorts, as well as the functional form and estimation technique. The results also suggest that the sample of published estimates possibly suffers from two types of publication bias, an under-representation of insignificant effects for small samples, and bias towards supportive effects in the earlier years followed by a bias towards negative effects as the literature matured.All correspondence to: Brigitte Waldorf. The authors appreciate the insightful comments and suggestions from two anonymous reviewers. The research also benefited from discussions with participants of the International Colloquium on Meta-analysis in Economics, Free University, Amsterdam, The Netherlands, December 2002. Finally, we would like to thank David Brown, Meagan Cahill, Angela Donelson, Calvin Farris, and Melaney Seacat from the University of Arizona for their research assistance. Responsible editor: Junsen Zhang.     

An investigation of the age of an alleged centenarian

At times, persons have been reported as living to extremely advanced ages such as 130, or even higher (McWhirter and McWhirter, 1977, p. 26; Medvedev, 1974; Merrill, 1976). However, controlled studies of closed groups like Civil War veterans (Myers and Shudde, 1955) have not shown any persons surviving beyond age 110, when age has been reasonably verified. It seems, therefore, highly plausible that reports of extremely advanced ages at death reflect exaggerations of age rather than reality. This note reports a case history which supports this view and illustrates how ages can be verified using available census data.     

Procedures in the biochemical estimation of age of vertebrates

Summary The most accurate method known to data for estimating age of wild vertebrates involves biochemical assay of eye lens proteins. Laboratory procedures that may be unfamiliar to many ecologists are described in detail. The method is based on precise changes in the amount of insoluble lens protein, and consists of two procedures: obtaining the appropriate lens fraction, and quantitatively analyzing its protein composition. Lenses are homogenized, and the insoluble fraction isolated by centrifugation. Protein content is measured colorimetrically by using the Lowry test. Instructions are given for single and double-beam spectrophotometers.