Impact of physical activity and sedentary behaviour on fall risks in older people: a systematic review and meta-analysis of observational studies

The objective of this work was to summarise and evaluate the evidence showing that physical activity is a protector factor as regards falls in older people. Relevant studies were identified through a systematic search in the MEDLINE and Cochrane Library, under the keywords of accidental fall/numerical data and risk factors, and with the bibliographies of retrieved papers. The combined odds ratio (OR) [95% confidence interval] for physical activity was 0.75 [0.64, 0.88] with moderate heterogeneity (I ²?=?33%). For fall injury, it was 0.59 [0.47, 0.74] and, for falls in general, it rose to 0.94 [0.76, 1.17] with nil heterogeneity. The combined OR for sedentary factors was 1.14 [1.10, 1.82] with moderate heterogeneity (I ²?=?36%). Regular physical activity in daily life yields significant reduction in falls in older people, especially falls with injuries.     

Quantifying Economic Dependency

In this paper we compare several types of economic dependency ratios for a selection of European countries. These dependency ratios take into account not only the demographic structure of the population, but also the differences in age-specific economic behaviour such as labour market activity, income and consumption as well as age-specific public transfers. In selected simulations where we combine patterns of age-specific economic behaviour and transfers with population projections, we show that in all countries population ageing would lead to a pronounced increase in dependency ratios if present age-specific patterns were not to change. Our analysis of cross-country differences in economic dependency demonstrates that these differences are driven by both differences in age-specific economic behaviour and in the age composition of the populations. The choice of which dependency ratio to use in a specific policy context is determined by the nature of the question to be answered. The comparison of our various dependency ratios across countries gives insights into which strategies might be effective in mitigating the expected increase in economic dependency due to demographic change.     

Coherence principles in interval‐based dose finding

This paper studies the notion of coherence in interval‐based dose‐finding methods. An incoherent decision is either (a) a recommendation to escalate the dose following an observed dose‐limiting toxicity or (b) a recommendation to deescalate the dose following a non–dose‐limiting toxicity. In a simulated example, we illustrate that the Bayesian optimal interval method and the Keyboard method are not coherent. We generated dose‐limiting toxicity outcomes under an assumed set of true probabilities for a trial of n=36 patients in cohorts of size 1, and we counted the number of incoherent dosing decisions that were made throughout this simulated trial. Each of the methods studied resulted in 13/36 (36%) incoherent decisions in the simulated trial. Additionally, for two different target dose‐limiting toxicity rates, 20% and 30%, and a sample size of n=30 patients, we randomly generated 100 dose‐toxicity curves and tabulated the number of incoherent decisions made by each method in 1000 simulated trials under each curve. For each method studied, the probability of incurring at least one incoherent decision during the conduct of a single trial is greater than 75%. Coherency is an important principle in the conduct of dose‐finding trials. Interval‐based methods violate this principle for cohorts of size 1 and require additional modifications to overcome this shortcoming. Researchers need to take a closer look at the dose assignment behavior of interval‐based methods when using them to plan dose‐finding studies.     

The role of reciprocation in social network formation,with an application to LiveJournal

This paper deals with the role of reciprocation in the formation of individuals’ social networks. We follow the activity of a panel of bloggers over more than a year and investigate the extent to which initiating a relation brings about its reciprocation. We adapt a standard capital investment model to study how reciprocation affects the build-up of the individual social capital of bloggers, as measured by their links and interactions with others. This allows us to measure the role of content production and relationship building in the dynamics of online social networks and to distinguish between the social networking and media aspects of blogging.     

Are Individuals’ Desired Family Sizes Stable? Evidence from West German Panel Data

Using West German panel data constructed from the 1988 and 1994/1995 wave of the DJI Familiensurvey, we analyze the stability and determinants of individuals’ total desired fertility. We find considerable variation of total desired fertility across respondents and across interviews. In particular, up to 50% of individuals report a different total desired fertility across survey waves. Multivariate analysis confirms the importance of background factors including growing up with both parents, having more siblings, and being Catholic for preference formation. Consistent with the idea that life course experiences provide new information regarding the expected costs and benefits of different family sizes, the influence of background factors on total desired fertility is strong early in life and weakens as subsequent life course experiences, including childbearing, take effect. Accounting for unobserved individual heterogeneity, we estimate that an additional child may increase the total desired fertility of women with children by 0.14 children, less than what conventional estimates from cross-sectional data would have suggested.     

Minority employment in the construction trades

This paper examines employment in the construction trades by race and skill level across 162 large U.S. metropolitan areas. The results reveal significant negative wage and positive scale effects on construction employment, especially for minorities and laborers, and thus imply that repeal of the Davis-Bacon Act, which requires “prevailing wages ” to be paid on federally funded construction projects, would yield substantial efficiency and equity gains. Conservative estimates suggest that Davis-Bacon repeal would increase construction employment by at least 36,000, including jobs for 27,000 minorities and 10,000 laborers. I am grateful to Burt Barnow, Barry Hirsch, and the anonymous referee for helpful comments on earlier drafts of this paper; Barry Hirsch and David Macpherson for preparing and thoroughly answering questions regarding their database provided to me through the Bureau of National Affairs; and Mindy Berry for careful research assistance.     

Political support for minimum wage legislation

Conclusion Even if minimum wage laws reduce employment opportunities for some workers, other individuals may benefit from their enactment. In particular, union members and residents of states with high wage levels would be expected to encourage their senators to vote in favor of minimum wage legislation. Examination of senators’ votes on the 1966 and 1974 minimum wage bills indicates that senators favoring passage of these bills are likely to come from states with high union membership and, to a lesser extent, high wage levels. The equations explaining senators’ votes on these bills were disaggregated by political party affiliation and length of membership in the Senate. Democrats were more likely than Republicans to support minimum wage bills. Virtually no difference was observed between senators who voted on both the 1966 and 1974 measures and those who voted on only one. Perhaps the most encouraging result reported is the similarity of coefficients generally observed for corresponding 1966 and 1974 equations. This similarity suggests that the equations reported herein could be used to predict votes on future minimum wage bills. The results suggest also that the general mode of analysis can be fruitfully applied to other economic legislation.     

Political support for minimum wage legislation: 1989

A model explaining senators’ votes on minimum wage increases in 1966 and 1974 was applied to the 1977 and 1989 votes with similar results. The extent of unionization in each state was positively associated with votes in favor of minimum wage increases. State wage levels were not significantly associated with senators’ votes. These results held for Republican senators as well as for all senators. However, neither wage levels nor unionization rates was a significant factor explaning Democrats’ votes on minimum wage increases.     

Peripheries,suburbanisms and change in sub-Saharan African cities

The ‘revisionist’ view of South African history has an advantage in understanding the role of values in terms of class structures, as opposed to liberal orthodoxy that sees ‘race’ as an autonomous variable: a view that is both static and unhistorical. The problem of explaining these values, however remains for class analysis can be accused of economic determinism. Pluralism may, therefore, be of use as a supplement to class analysis by interpreting values in a subjective sense. Class becomes only one of a number of forms of political consciousness (i.e. religious, ‘tribal’ or ethnic) and the analysis shifts to a market of competing political ideologies. This view is explored empirically by the example of the rise of a segregationist ideology in South Africa in the twentieth century.