Including Age Structure Research Articles

Global, Regional and National Burden of Paediatric Atopic Dermatitis: A Trend and Geographic Inequalities Analysis.

Atopic dermatitis (AD) is a common chronic skin disorder in children. We aimed to investigate trends and regional disparities of burden in paediatric AD at global, regional and national levels, and to explore potential associated factors. Based on data from Global Burden of Disease study 2019, we assessed trends in burden of AD aged <19 years from 1990 to 2019, including prevalent and incident cases, age-standardised prevalence and age-standardised incidence. For potential associated factors, correlations of above trends and indexes of socio-economic status (sociodemographic index, SDI) and health service coverage (universal health coverage index, UHCI) were evaluated. We conducted decomposition analysis to understand the net contribution of population-level factors and their contribution proportions on changes of prevalent and incident cases, including age structure, population change and epidemiological change. Global prevalent and incident cases of paediatric AD increased by about 5.7 and 0.7 million between 1990 and 2019, respectively. Global age-standardised prevalence and incidence decreased by -0.17% (-0.19% to -0.16%) and -0.12% (-0.13% to -0.11%) per year from 1990 to 2019, respectively. Regionally, the highest increase of prevalent and incident cases was in low SDI region (by 96.77% and 84.85%); the highest decrease of age-standardised prevalence and incidence was in high SDI regions (by -0.20% and -0.27% per year). The correlation analyses identified significant negative correlations between trends and SDI and UHCI. Population change was a major driver of case rise; epidemiological change and age structure showed negative impact of case rise. Regional disparities in contribution of three population-level factors were seen, including net contribution direction (positive or negative) and contribution proportion levels. Global paediatric AD case numbers increased, primarily due to population growth. Prevalence and incidence decreased slightly. Geographic inequalities were seen. Developing region-specific strategies targeting potential factors is essential to reduce paediatric AD burden.

Social business environment and transnational corporations’ loyalty: the executives’ perceptions in Tanzania

The economic growth of the host low-income countries, which depends on foreign investments, among other things, has been impacted by the disloyal behaviours of foreign firms, including transnational corporations (TNCs). The demonstrated disloyal behaviours include the closure of operations and productions, scaling back expansion plans, and shifting income-generating operations to other countries with favourable business settings. This study examines the influence of the social business environment (SBE) on TNCs loyalty towards the host country, Tanzania. A cross-sectional design was employed to collect data from 131 TNCs in Tanzania using a structured questionnaire. The hypotheses were tested by hierarchical regression analysis. Findings reveal that the SBE has a positive and significant effect on TNCs loyalty through social attitudes, language, consumer preferences, and attitudes towards foreign businesses. Other dimensions of SBE, including age structure, gender roles, and the population’s literacy level, have negative and insignificant effects. Among all dimensions of the SBE, language is the best predictor of TNCs loyalty in Tanzania, followed by social attitudes, customer preferences, and attitudes of society towards foreign businesses. Based on the results, it is suggested that policymakers establish consistent social policies that encourage favourable social attitudes and beliefs, local and international language usage and proficiency, predictable customer preferences, and amicable attitudes of society towards foreign businesses to stimulate high TNC loyalty in Tanzania, which is crucial for sustainable economic development.

Modelling COVID-19 vaccine breakthrough infections in highly vaccinated Israel-The effects of waning immunity and third vaccination dose.

In August 2021, a major wave of the SARS-CoV-2 Delta variant erupted in the highly vaccinated population of Israel. The transmission advantage of the Delta variant enabled it to replace the Alpha variant in approximately two months. The outbreak led to an unexpectedly large proportion of breakthrough infections (BTI)-a phenomenon that received worldwide attention. Most of the Israeli population, especially those aged 60+, received their second dose of the vaccination four months before the invasion of the Delta variant. Hence, either the vaccine induced immunity dropped significantly or the Delta variant possesses immunity escaping abilities, or both. In this work, we model data obtained from the Israeli Ministry of Health, to help understand the epidemiological factors involved in the outbreak. We propose a mathematical model that captures a multitude of factors, including age structure, the time varying vaccine efficacy, time varying transmission rate, BTIs, reduced susceptibility and infectivity of vaccinated individuals, protection duration of the vaccine induced immunity, and the vaccine distribution. We fitted our model to COVID-19 cases among the vaccinated and unvaccinated, for <60 and 60+ age groups, and quantified the transmission rate, the vaccine efficacy over time and the impact of the third dose booster vaccine. The peak transmission rate of the Delta variant was found to be 2.14 times higher than that of the Alpha variant. The two-dose vaccine efficacy against infection dropped significantly from >90% to ~40% over 6 months. We further performed model simulations and quantified counterfactual scenarios examining what would happen if the booster had not been rolled out. We estimated that approximately 4.03 million infective cases (95%CI 3.19, 4.86) were prevented by vaccination overall, and 1.22 million infective cases (95%CI 0.89, 1.62) averted by the booster.

Tuberculosis screening among children and adolescents in China: insights from a mathematical model

BackgroundTuberculosis (TB) continues to be prevalent in China also among children and adolescents in China. We built a dynamic mathematical model for TB transmission in China, and applied it to compare the epidemic trends 2021–2030 under a range of screening interventions focusing on children and adolescents. MethodsWe developed a dynamic mathematical model with a flexible structure. The model can be applied either stochastically or deterministically, and can encompass arbitrary age structure and resistance levels. In the present version, we used the deterministic version excluding resistance but including age structure with six groups: 0–5, 6–11, 12–14, 15–17, 18–64, and 65 years and above. We parameterized the model by literature data and fitting it to case and death estimates provided by the World Health Organization. We compared the new TB cases and TB-related deaths in each age group over the period 2021–2030 in 10 scenarios that involved intensified screening of particular age groups of children, adolescents, or young adults, or decreased or increased diagnostic accuracy of the screening. ResultsScreening the entire age class of 18-year-old persons would prevent 517,000 TB cases and 14,600 TB-related deaths between years 2021 and 2030, corresponding to 6.6% and 5.5% decrease from the standard of care projection, respectively. Annual screening of children aged 6–11 and, to a lesser extent, 0–5 years, also reduced TB incidence and mortality, particularly among children of the respective ages but also in other age groups. In contrast, intensified screening of adolescents did not have a major impact. Screening with a simpler and less accurate method resulted in worsened outcomes, which could not be offset by more intensive screening. More accurate screening and better sensitivity to detect latent TB could prevent 2.3 million TB cases and 68,500 TB deaths in the coming 10 years. ConclusionRoutine screening in schools can efficiently reduce the burden of TB in China. Screening should be intensified particularly among children in primary school age.

Aging in Place Since the COVID-19 Pandemic Onset: A Qualitative Study of Neighborhood Engagement

The COVID-19 pandemic may fundamentally change neighborhood environments and ways of aging in place. This research aimed to investigate perceptions of and engagement in neighborhoods since the pandemic onset among online survey respondents of the COVID-19 Coping Study. We analyzed a random stratified sample of 500 open-ended responses collected July-September 2020 with quotas for age, gender, race/ethnicity, and education to match the US population aged 55+. Qualitative thematic analysis identified both increased and decreased local activity and varying levels of social interaction, support, and civic engagement. Community characteristics including age structure, socioeconomic diversity, density, housing patterns, weather, and social infrastructure were related to neighborhood perceptions. These interacted with personal characteristics such as duration of residence, living arrangements, family closeness, health status, and preferred lifestyle. Results highlight coping strategies among aging adults and their neighbors, sources of individual and community vulnerability, and opportunities to strengthen social infrastructure and resiliency within neighborhoods.

Demographics and Management of the Isolated Upper Missouri River Paddlefish Stock of Fort Peck Reservoir, Montana

AbstractPaddlefish Polyodon spathula inhabiting Fort Peck Reservoir and the upper Missouri River, Montana, are members of the northern‐most and western‐most isolated group of the species. These isolated fish support a recreational, river‐based snag fishery on migratory adults. We provide population demographics for the Fort Peck Paddlefish stock, including age structure, growth, reproductive success, recruitment, and population trends developed from creel surveys, adult fish tagging, and reservoir surveys of age‐0 and age‐1 fish over the period 1992–2020. Of 5,108 fish (2,560 males; 2,558 females), mean annual male age ranged from 18.5 to 21.5 years; mean age of females ranged from 24.3 to 30.8 years. Males did not mature until at least 9–12 years, whereas females did not mature until at least ages 16–19. Females were longer and much heavier than males at a given age and throughout adult life. Males exhibited both annual and biennial spawning, whereas almost no females showed consecutive‐year spawning but commonly showed biennial spawning. Annual survival rates estimated from cumulative catch curves were 85% for males and 88% for females. Low counts of age‐0 and age‐1 fish in the reservoir as well as the modest numbers of young male recruits to the fishery indicate that the Fort Peck stock is characterized by a fairly steady but modest recruitment. This isolated stock continues to be managed as a recreational fishery with harvest while maintaining adult population size, sex, and age structure consistent with its recruitment.

Global stability of age-of-infection multiscale HCV model with therapy.

In order to treat the diseases caused by hepatitis C virus (HCV) more efficiently, the concentration of HCV in blood, cells, tissues and the body has attracted widespread attention from related scholars. This paper studies a dynamic dependent HCV model (more specifically, including age structure and treatment methods model) that concludes states of infection-free and infected equilibrium. Through eigenvalue analysis and Volterra integral formula, it proves that $E_0$ is globally asymptotically stable when $\mathcal{R}<1$. After explaining the existence, uniqueness and positive properties of the solution of the system, we have proved the global asymptotic stability of $E^*$ when $\mathcal{R}>1$ by constructing a suitable Lyapunov function. Through the above proofs, it can be concluded that effective treatment measures can significantly reduce the number of HCVs, so many related researchers are aware of the importance of highly efficient nursing methods and are committed to applying relevant methods to practice.

Pathological Findings in White-Beaked Dolphins (Lagenorhynchus albirostris) and Atlantic White-Sided Dolphins (Lagenorhynchus acutus) From the South-Eastern North Sea.

In the North Sea, white-beaked dolphins (Lagenorhynchus albirostris) occur regularly and are the second most common cetacean in the area, while their close relative, the Atlantic white-sided dolphin (Lagenorhynchus acutus), prefers the deeper waters of the northern North Sea and adjacent Atlantic Ocean. Though strandings of both species have occurred regularly in the past three decades, they have decreased in the southern North Sea during the last years. Studies describing necropsy findings in stranded Lagenorhynchus spp. are, to date, still scarce, while information gained through post-mortem examinations may reveal valuable information about underlying causes of this decline, including age structure and the reproduction status. Therefore, we retrospectively assessed and compared the necropsy results from fresh Lagenorhynchus spp. stranded along the southeastern North Sea between 1990 and 2019. A full necropsy was performed on 24 white-beaked dolphins and three Atlantic white-sided dolphins from the German and Dutch coast. Samples of selected organs were taken for histopathological, bacteriological, mycological, parasitological and virological examinations. The most common post-mortem findings were emaciation, gastritis and pneumonia. Gastritis and ulceration of the stomach was often associated with an anisakid nematode infection. Pneumonia was most likely caused by bacterial infections. Encephalitis was observed in three animals and morbillivirus antigen was detected immunohistochemically in one case. Although the animal also showed pneumonic lesions, virus antigen was only found in the brain. Parasitic infections mainly affected the gastro-intestinal tract. Lungworm infections were only detected in two cases and no associations with pathological alterations were observed. Stenurus spp. were identified in two of three cases of parasitic infections of the ears. Twelve of the 26 white-beaked dolphins stranded in Germany were found between 1993 and 1994, but there was no evidence of epizootic disease events or mass strandings during the monitored period.

Long-term heavy metal pollution varied female reproduction investment in free-living anura, Bufo raddei

Environment contamination is known to affect the growth, reproduction, and even mortality of anuran species, and hence modulate their life history traits. Although knowledge of the ability of amphibians to cope with harsh environments has gained ongoing research, the reproductive strategy of free-living amphibians subjected to long-term heavy metal pollution is largely unknown. This study aimed to explore the variation in the life history traits, including age structure, maturation age, reproductive investment, and reproduction trade-off, in female Bufo raddei, a widespread anuran in Baiyin (BY) in northwest of China, subjected to sublethal heavy metal pollution. B. raddei collected from Liujiaxia (LJX), a relatively unpolluted area, were used as control. Skeletochronological analysis revealed variation in the average breeding age of females: more than 70% of females from BY began to breed 1 year before the toads collected from LJX. Females from BY tended to prioritize reproduction over survival and invested more in their first reproductive event. Further, females in BY with a high fluctuating asymmetry index showed a relatively lower reproductive investment. For trade-off in offspring number and size, BY population optimize larger clutch sizes with smaller egg size compared with population in LJX. Changes in female reproductive investment caused by heavy metal pollution might ultimately alter the structural stability of amphibian population.

Married Women’s Economic Independence and Divorce in the Nineteenth- and Early-Twentieth-Century United States

We analyze the effects of the Married Women’s Property Acts and Earnings Acts (EAs) on divorce rates in the late-nineteenth- and early-twentieth-century United States. We find that the property acts increased divorce rates, which is consistent with the predicted outcome, in household extensive bargaining models, of an increase in the married woman’s relative bargaining power. We also find some evidence that the EAs had a positive effect on divorce rates, though it is not statistically significant after accounting for the possibility that divorce rates changed prior to the enactment of an EA. To support our causal argument, we control for regional trends in the divorce rate and account for the timing of the laws’ effects. We also assess alternative explanations for the rise in divorce rates during the late nineteenth century, including age structure, divorce law, urbanization, economic development, and foreign immigration, and we find that only age structure and urbanization positively affected divorce rates along with the property acts. Finally, we provide support for our argument from court cases in which the acts were used to defend a woman’s property rights against claims from her ex-husband.

Optimizing selective cutting strategies for maximum carbon stocks and yield of Moso bamboo forest using BIOME-BGC model

The selective cutting method currently used in Moso bamboo forests has resulted in a reduction of stand productivity and carbon sequestration capacity. Given the time and labor expense involved in addressing this problem manually, simulation using an ecosystem model is the most suitable approach. The BIOME-BGC model was improved to suit managed Moso bamboo forests, which was adapted to include age structure, specific ecological processes and management measures of Moso bamboo forest. A field selective cutting experiment was done in nine plots with three cutting intensities (high-intensity, moderate-intensity and low-intensity) during 2010–2013, and biomass of these plots was measured for model validation. Then four selective cutting scenarios were simulated by the improved BIOME-BGC model to optimize the selective cutting timings, intervals, retained ages and intensities. The improved model matched the observed aboveground carbon density and yield of different plots, with a range of relative error from 9.83% to 15.74%. The results of different selective cutting scenarios suggested that the optimal selective cutting measure should be cutting 30% culms of age 6, 80% culms of age 7, and all culms thereafter (above age 8) in winter every other year. The vegetation carbon density and harvested carbon density of this selective cutting method can increase by 74.63% and 21.5%, respectively, compared with the current selective cutting measure. The optimized selective cutting measure developed in this study can significantly promote carbon density, yield, and carbon sink capacity in Moso bamboo forests.

Why the Development of Health Insurance Is Regionally Imbalanced: Evidence from China

ABSTRACTAs China adopted an imbalanced development strategy to obtain rapid economic growth, it is getting more and more urgent to find out a feasible way to balanced development of social safety network. This study measures the degree of regional disparities in China’s health insurance industry and explores the rationales by a thorough examination of health insurance purchasing behavior. An empirical analysis is conducted, based on a panel data of 31 provinces from 2004 to 2014, to test the hypothesis. We find that the regional disparities would be significantly affected by the variables including age structure, education, income, availability of health resources, density of population, and substitutes.

Hypertension and diabetes in Africa: design and implementation of a large population-based study of burden and risk factors in rural and urban Malawi.

BackgroundThe emerging burden of cardiovascular disease and diabetes in sub-Saharan Africa threatens the gains made in health by the major international effort to combat infectious diseases. There are few data on distribution of risk factors and outcomes in the region to inform an effective public health response. A comprehensive research programme is being developed aimed at accurately documenting the burden and drivers of NCDs in urban and rural Malawi; to design and test intervention strategies. The programme includes population surveys of all people aged 18 years and above, linking individuals with newly diagnosed hypertension and diabetes to healthcare and supporting clinical services. The successes, challenges and lessons learnt from the programme to date are discussed.ResultsOver 20,000 adults have been recruited in rural Karonga and urban Lilongwe. The urban population is significantly younger and wealthier than the rural population. Employed urban individuals, particularly males, give particular recruitment challenges; male participation rates were 80.3 % in the rural population and 43.6 % in urban, whilst female rates were 93.6 and 75.6 %, respectively. The study is generating high quality data on hypertension, diabetes, lipid abnormalities and risk factors.ConclusionsIt is feasible to develop large scale studies that can reliably inform the public health approach to diabetes, cardiovascular disease and other NCDs in Sub-Saharan Africa. It is essential for studies to capture both rural and urban populations to address disparities in risk factors, including age structure. Innovative approaches are needed to address the specific challenge of recruiting employed urban males.

On the Benefits of Including Age-Structure in Harvest Control Rules

This paper explores the benefits of including age structure in the control rule (HCR) when decision makers regard their (age-structured) models as approximations. We find that introducing age structure into the HCR reduces both the volatility of the spawning biomass and the yield. Although the benefits are lower at a fairly imprecise level, there are still major advantages for the actual precision with which the case study is assessed. Moreover, we find that when age-structure is included in the HCR the relative ranking of different policies in terms of variance in biomass and yield does not differ. These results are shown both theoretically and numerically by applying the model to the Southern Hake fishery.

When should plant population models include age structure?

Summary Most population models for plants are structured exclusively by size or stage. However, the assumption that age can be safely ignored has not been rigorously tested. We used an unprecedented data set from western North America on age‐specific demography of 19 populations of perennial grasses to determine when age structure can alter model behaviour. Based on the Akaike Information Criterion, the best statistical models included both size and age for 14 and 18 of the 19 populations for the growth and survival function, respectively. The inclusion of age reduced the sums of squared residuals by 0.1–5.6% for growth rates and reduced the residual deviance by 0.06–8.2% for survival rates. When we compared observed per capita growth rates with predictions from individual‐based models, we found that in eleven populations, models with age explained 1.3–45.8% (with a mean of 12.8%) more variance than size‐only models. Density‐dependent integral projection models showed that the inclusion of age had strong effects on equilibrium cover for some species but not others. When equilibrium cover differed, it was almost always higher in models with age. The population consequences of incorporating age were best predicted by the shape of a species' survival curve: equilibrium cover was most sensitive to inclusion of age structure for species with very hollow (Type III) survivorship curves. We speculate that age serves as a proxy for high individual‐level heterogeneity, which is known to generate Type III survivorship curves and can increase equilibrium abundance. Synthesis. Our results indicate that including age structure in models is most important for populations with strong Type III survivorship curves. For such populations, which are likely to contain high individual heterogeneity, models that ignore age could underestimate population growth rates and equilibrium cover. More research is needed to test whether our results, based on data from perennial grasses, also apply to other plant growth forms.

Maternal age, fecundity, egg quality, and recruitment: linking stock structure to recruitment using an age-structured Ricker model

Understanding the process of recruitment is fundamental to fisheries biology and management. However, recruitment in natural populations is highly variable and rarely well described by classical stock–recruitment relationships (SRRs). Recent analyses suggest that the age composition of the spawning biomass may play an important role in the mismatch between SRRs and data. Here we develop a generalization of the Ricker SRR that incorporates age structure by allowing mortality and fecundity rates to depend on maternal age. We provide a flexible SRR with biologically interpretable parameters that can be estimated from existing fisheries time series and use a Bayesian framework that enables parameters to be informed by experimental data. We apply our method to the Icelandic population of Atlantic cod ( Gadus morhua ) and show models that include age structure effects outperform the classical Ricker SRR that ignores age structure. Our results indicate a strong effect of spawning stock age structure on recruitment dynamics in this population. Our approach provides a biologically interpretable and immediately applicable method for investigating the consequences for spawning stock age structure on recruitment.

Can New Zealand achieve self‐sufficiency in its nursing workforce?

This paper reviews impacts on the nursing workforce of health policy and reforms of the past two decades and suggests reasons for both current difficulties in retaining nurses in the workforce and measures to achieve short-term improvements. Difficulties in retaining nurses in the New Zealand workforce have contributed to nursing shortages, leading to a dependence on overseas recruitment. In a context of global shortages and having to compete in a global nursing labour market, an alternative to dependence on overseas nurses is self-sufficiency. Discursive paper. Analysis of nursing workforce data highlighted threats to self-sufficiency, including age structure, high rates of emigration of New Zealand nurses with reliance on overseas nurses and an annual output of nurses that is insufficient to replace both expected retiring nurses and emigrating nurses. A review of recent policy and other documents indicates that two decades of health reform and lack of a strategic focus on nursing has contributed to shortages. Recent strategic approaches to the nursing workforce have included workforce stocktakes, integrated health workforce development and nursing workforce projections, with a single authority now responsible for planning, education, training and development for all health professions and sectors. Current health and nursing workforce development strategies offer wide-ranging and ambitious approaches. An alternative approach is advocated: based on workforce data analysis, pressing threats to self-sufficiency and measures available are identified to achieve, in the short term, the maximum impact on retaining nurses. A human resources in health approach is recommended that focuses on employment conditions and professional nursing as well as recruitment and retention strategies. Nursing is identified as 'crucial' to meeting demands for health care. A shortage of nurses threatens delivery of health services and supports the case for self-sufficiency in the nursing workforce.

Population Dynamics of the Sand Shiner (Notropis stramineus) in Non-Wadeable Rivers of lowa

ABSTRACT The sand shiner (Notropis stramineus) is a common cyprinid found throughout the Great Plains region of North America that plays an important ecological role in aquatic systems. This study was conducted to describe population dynamics of sand shiners including age structure, growth, mortality, and recruitment variability in 15 non-wadeable rivers in Iowa. Fish were collected during June-August (2007–2008) using a modified Missouri trawl, a seine, and boat-mounted electrofishing. Scales were removed for age and growth analysis. A total of 3,443 fish was sampled from 15 populations across Iowa, of which 676 were aged. Iowa's sand shiner populations consisted primarily of age-1 fish (53% of all fish sampled), followed by age-2 fish (30%), age-0 fish (15%), and age-3 fish (2%). Sand shiners grew an average of 38.5 mm (SE = 5.7) during their first year, 13.8 mm (4.5) during their second year, and 9.0 mm (6.9) during their third year. Total annual mortality varied from 35.0% to 92.3% among populations with a mean of 77.9% (0.2). Incremental mortality rates were 84.5% (0.2) between age 1 and age 2, and 92.0% (0.1) between age 2 and age 3. Recruitment was highly variable, as indicated by a mean recruitment variation index of-0.12 (0.54). Overall, the sand shiner was characterized by relatively low mean age, fast growth, high mortality, and high recruitment variability. Indices of sand shiner population dynamics were poorly correlated with habitat characteristics.

Senescence can explain microbial persistence

It has been known for many years that small fractions of persister cells resist killing in many bacterial colony-antimicrobial confrontations. These persisters are not believed to be mutants. Rather it has been hypothesized that they are phenotypic variants. Current models allow cells to switch in and out of the persister phenotype. Here, a different explanation is suggested for persistence, namely senescence. Using a mathematical model including age structure, it is shown that senescence provides a natural explanation for persistence-related phenomena, including the observations that the persister fraction depends on growth phase in batch culture and dilution rate in continuous culture.

The complex effects of demographic heterogeneity on the interaction between the economy and population

This paper combines population dynamics and macroeconomics in a world with structural unemployment. A general demo-economic framework, including age structure, is used to investigate the dynamical role played by fertility heterogeneity between employed and unemployed individuals. Several noteworthy dynamic features arise. First, under Malthusian conditions, i.e., when the fertility of unemployed individuals always lies below that of wage earners, the interaction between heterogeneous fertility and age structure may lead to sustained oscillations depending on the age patterns of entry in the labour market. This is an example of stable Malthusian cycle. Second, under post-Malthusian conditions, both transient and robust chaotic phenomena may appear.