Societal change related to individualisation has likely made individual resources more important for the maintenance of social ties. This raises the question whether lower-educated adults are more disadvantaged in later-born cohorts in personal network structure and function. Observations are from 4,886 individuals aged 55 and over from the Longitudinal Aging Study Amsterdam (LASA), who are followed over a timespan of a maximum of 24 years between 1992 and 2016. Multi-level regression models are estimated to determine cohort differences. Network size is larger in later-born cohorts, and more so for the higher-educated than for the lower-educated adults. Network diversity increases across birth cohorts irrespective of educational level. Lower- and higher-educated women, and lower-educated men give more instrumental support in later-born cohorts, whereas higher-educated men do not show such a steep increase. More emotional and instrumental support is also received in later-born cohorts irrespective of educational level, but higher-educated adults receive more emotional support in all birth cohorts. Thus, lower-educated older adults are not necessarily worse off socially in later-born cohorts. Instead, they are even more likely to be active givers of support. Also, most of the gains in personal networks of older adults in later-born cohorts are independent of educational level, suggesting that the social landscape for older adults today is much richer.

The ability to use the internet frequently is likely to provide a useful means of engaging with society and using services in later life, yet older people are the most likely to suffer digital exclusion, with those of the oldest ages at the greatest risk. Using six waves (2002–2012) of the English Longitudinal Study of Ageing, we model cohort-specific patterns of frequent internet use for people aged 50 and over. Multi-level growth models are used to observe trajectories of internet use over the ten-year period. Firstly, analyses are stratified by gender and wealth, and secondly we additionally test for health effects. The study finds cohort-specific differences in patterns of internet use. Rates of internet use increase faster among younger cohorts yet, despite initially increasing, begin to decline among older cohorts. Poor health is shown to be a key factor in shaping the trajectory of internet use over time. Rates of internet use are consistently lower for women than men and for those in poorer financial circumstances, independently of age cohort. The findings demonstrate the importance of ensuring older people can remain digitally included throughout later life, including after the onset of poorer health, especially as some of these individuals might benefit the most from some of the services the internet can provide.

Recent societal changes have increased the salience of non-kin relationships. It can be questioned whether network types that are more strongly non-kin-based give more informal care nowadays. We study how informal care use differs according to network type for three birth cohorts. Data from the Longitudinal Aging Study Amsterdam (LASA) on older adults aged 75–84 years, interviewed in 1992, 2002 and 2012, respectively (total sample size N = 2,151, analytical sample having functional limitations N = 926). We found four network types: restricted, family-focused with a partner, family-focused without a partner and wider community-focused diverse networks. Wider community-focused diverse networks are more common in the late birth cohort, whereas restricted networks and family-focused networks without a partner are less common. Logistic regression analyses reveal that those in a family-focused network with a partner use informal care more often than those in the other three network types, and insignificant interaction terms show that this does not differ by birth cohort. Irrespective of their network type, those in the late birth cohort use informal care less often. However, after controlling for need, predisposing and context factors, this cohort-difference is no longer significant. We conclude that despite large-scale societal changes, wider community-focused diverse networks do not provide more informal care than before and that among the functionally impaired, the odds of receiving informal care does not decline across birth cohorts.

Knowledge of Palmer amaranth demographics and biology is essential for the development and implementation of weed management strategies. A field experiment was conducted to investigate the effects of Palmer amaranth density on seedling mortality, flowering initiation, and flowering progress throughout the growing season and biomass production and fecundity in wide-row soybean. The experimental design was a randomized complete block design with three levels of Palmer amaranth density-clusters: high, medium, and low. Palmer amaranth mortality rate was greater at high Palmer amaranth population density-cluster, reaching a peak within 30 to 40 d after Palmer amaranth emergence (DAE) (0.55 and 0.80 for 2014 and 2015, respectively), in comparison with mortality rate at medium and lower density-clusters. Likewise, as Palmer amaranth density increased, biomass and seed production per unit area of the weed also increased. Biomass production at the high density-cluster in 2014 was 664.7 g m−2 compared with 542.9 and 422.1 g m−2 at medium and low density-clusters, respectively. Similarly, biomass production at high density-cluster in 2015 was 100.6 g m−2 compared with 37.3 and 34.2 at medium and low density-clusters, respectively. In addition, seeds produced at high density-cluster were 1.5 million and 245,400 seeds m−2 for 2014 and 2015, respectively. Seed production was reduced by 29% and 54% in 2014 and by 65% and 75% in 2015 at medium and low density-clusters, respectively. Earlier flowering initiation (i.e., between 30 to 40 DAE) occurred in higher Palmer amaranth density-clusters, indicating a trade-off between reproduction and survival at high densities and more stressed environments for species survival. Palmer amaranth male-to-female sex ratio was greater at high densities, 1.3 and 1.9, compared with lower densities of 0.6 to 0.7 and 0.7 to 0.8 in 2014 and 2015, respectively. The plasticity of Palmer amaranth population and population-structure regulation, vegetative growth, and flowering shifts at various levels of intraspecific competition (i.e., high vs. low population density-clusters) and the trade-off between these biological transitions merits further investigation.

This paper examines the extent to which an individual's income-status position relative to that of others in the same cohort is maintained over the later life course. Changes in the income status of individuals born between 1924 and 1928 are estimated by means of synthetic cohort methods. Using a series of cross-sectional data files from every fifth Survey of Consumer Finances, starting in 1978, the findings show that, from ages 50 to 64, persons of this birth cohort with early-life socio-economic status advantages (namely high education) improve their absolute and relative income status position vis-à-vis others with status disadvantages. For ages 65 to 74, the economic well-being of individuals with status advantages and disadvantages converge. Since Canada's public pension programs are relatively well developed in terms of comprehensiveness and generosity, they do a good job at countering the effects of status background characteristics on the distribution of income in old age. In the absence of these programs (i.e., up to age 64), the relative position of those with high education and other advantaged groups is strengthened.

In outbreaks of foodborne disease associated with retail outlets, the outlet often closes as a precaution before the specific food vehicle has been identified. Suspect food vehicles may be named as part of general control measures. A conventional case-control study cannot be performed because both cases and potential controls are likely to be aware of the hypothesis and therefore potentially biased. Modern sales recording systems in many food retail outlets may provide a basis for constructing a virtual cohort and allow a statistical inference to be made about various possible vehicles of infection. In 2007, an outbreak of E. coli O157 infection in Paisley, Scotland, was linked to cooked meat from a supermarket delicatessen using descriptive epidemiology. Construction of a virtual cohort allowed a relative risk and confidence interval to be estimated which supported the hypothesis of cooked beef topside being the vehicle of infection. This novel method could be valuable in the investigation of future outbreaks.

This study uses a novel method for discriminating cohorts and investigating the population dynamics of the parasitic crustacean, Argulus foliaceus. Analysis of parasite length-frequency data was carried out in order to elucidate the timings and drivers behind the parasite's life cycle. Up to 6 cohorts of the parasite emerge through the course of 1 year in still-water trout fisheries in England. Recruitment ceases over the winter months; however, 3 cohorts of the parasite over-winter, 2 as eggs and 1 as a hatched stage. The technique, when used in conjunction with temperature data, also allowed for the reliable prediction of growth rates and provided estimates of egg incubation times and the length of hatching periods. These data showed that growth rates increased exponentially between the observed temperatures of 4 to 22°C. The method allowed for the time taken from hatching to egg laying under field conditions to be predicted and produced estimates that were validated against independent laboratory studies on the growth of the parasite.

The experience of retirement and old age of two cohorts of the residents of Paris, born successively around 1907 and 1921, have been studied through prospective longitudinal studies, each of which comprised several waves of interviews. The two cohorts were first interviewed as they approached retirement and old age, in respectively 1972 and 1984. Moulded by the strong contemporaneous social change, the principal life experiences of the two cohorts have been quite different – from the social and geographic settings of their birth, their childhood and education, through their occupations and career advancement, parenting and family lives, housing conditions and residential mobility, earned incomes and pensions, longevity, and utilisation of medical care. Above all, their long lives have been strongly conditioned by rapid and radical socio-economic changes, particularly in the occupational structure, the rising standard of living, and improvements in urban housing standards, social protection, personal services and average life span. In contrast to their rising material standards, the cohorts have faced the gradual spread of less sympathetic attitudes towards older people, particularly those who lose their autonomy. As the number of people in advanced old age has relentlessly increased, they have in several respects become more distant from the rest of society. Maintaining the continued ‘inclusion’ and full citizenship of frail older people is not only a growing moral and practical problem, but also a major political problem in a democracy.