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Given the jump–decay citation patterns discussed in the previous chapter, are we forced to conclude that the papers we publish will be relevant for only a few years? We find that while aggregate citations follow a clear pattern, the trajectories of individual citations are remarkably variable. Yet, by analyzing individual citation histories, we are able to isolate three parameters – immediacy, longevity, and fitness – that dictate a paper’s future impact. In fact, all citation histories are governed by a single formula, a fact which speaks the universality of the dynamics that at first seemed quite variant. We end by discussing how a paper’s ultimate impact can be predicted using one factor alone: its relative fitness. We show how papers with the same fitness will acquire the same number of citations in the long run, regardless of which journals they are published in.
The study characterized the structure of juveniles and sub-adults of Farfantepenaeus brasiliensis and F. paulensis in the Cananéia-Iguape estuarine lagoon system and its adjacent coastal area by evaluating the period of juvenile recruitment, sex ratio, growth, longevity, natural mortality, and development time until the late juvenile phase. Samples were collected from July 2012 to June 2014. Shrimps were identified by species and sex, and measured (carapace length – CL mm); 889 individuals of F. brasiliensis and 848 of F. paulensis were analysed. Females were more abundant than males for both species. The growth parameters of F. brasiliensis were: CL∞ = 45.5 mm, k = 1.8 year−1 for males and CL∞ = 55.2 mm, k = 1.6 year−1 for females; longevity of 2.52 years (males) and 2.88 years (females); and natural mortality of 1.71 (males) and 1.55 (females). For F. paulensis, the following values were observed: CL∞ = 40.7 mm, k = 2.3 year−1 for males and CL∞ = 56.5 mm, k = 1.9 year−1 for females; longevity of 2.04 years (males) and 2.37 years (females); and natural mortality of 2.39 (males) and 2.05 (females). The juvenile recruitment of both species peaked in January 2014. The development time until late juvenile phase was ~7 months (F. brasiliensis) and ~5 months (F. paulensis). Even though the highest abundance of juveniles did not occur in the closed season, fishing is forbidden in the estuarine area and the migration towards the adult population occurred close to or even during the closed season.
In many human populations, especially those living in regions with pronounced climatic differences between seasons, the most sensitive (prenatal and neonatal) developmental stages occur in contrasting conditions depending on the season of conception. The difference in prenatal and postnatal environments may be a factor significantly affecting human development and risk for later life chronic diseases. Factors potentially contributing to this kind of developmental programming include nutrition, outdoor temperature, infectious exposures, duration of sunlight, vitamin D synthesis, etc. Month of birth is commonly used as a proxy for exposures which vary seasonally around the perinatal period. Season-of-birth patterns have been identified for many chronic health outcomes. In this review, the research evidence for the seasonality of birth in adult-life disorders is provided and potential mechanisms underlying the phenomenon of early life seasonal programming of chronic disease and longevity are discussed.
Size-frequency analysis of the echinoid Echinocyamus pusillus from six offshore areas in the southern North Sea and eastern English Channel reveal five distinct cohorts, suggesting a lifespan of five years. In all six individual areas one or more year-groups are absent, due to the unsuccessful recruitment of planktonic larvae to the seabed in some years, giving a false impression of a shorter lifespan. A relatively long lifespan and planktotrophic larval development are remarkable for such a small species, which reaches a maximum test length of 7.3 mm in the area, such traits being more typical of large-sized macrobenthic species. The feeding mode is akin to that of many meiobenthic taxa. The architecture of the test confers exceptional strength and resilience to mechanical perturbation.
This paper explores the concept of the completed life outlined in recent writing in the Netherlands on euthanasia and assisted suicide and its implications for ageing studies. Central to this theme is the basic right of people to self-determine the length of their later life, linked with the subsidiary right to assistance in achieving such self-determination. Although the notion of weariness with life has a long history, the recent advocacy of a self-limited life seems shaped by the new social movements presaged upon individual rights together with what might be called a distinctly third-age habitus, giving centre stage to autonomy over the nature and extent of a desired later life, including choice over the manner and timing of a person's ending. In exploring this concept, consideration is given to the notion of a ‘right to die’, ‘rational suicide’ and the inclusion of death as a lifestyle choice. While reservations are noted over the unequivocal good attached to such self-determination, including the limits to freedom imposed by the duty to avoid hurt to society, the article concludes by seeing the notion of a completed life as a challenge to traditional ideas about later life.
Peristenus spretus (Hymenoptera: Braconidae) is one of the most important endoparasitoids used for biological control of the green mirid bug, Apolygus lucorum Meyer-Dür (Heteroptera: Miridae). However, what we know about its reproductive genetics is very limited. Here, the composition of ovarian proteins in P. spretus was analyzed. Mass spectrum data searched against the non-redundant NCBI protein and UniProt protein database identified 1382 proteins and revealed an enrichment of the heat shock protein 83 (HSP83) in P. spretus ovary. The Pshsp83 complete cDNA is 2175 bp in length and encodes a protein of 724 amino acids with a calculated molecular mass of 83.4 kDa and a theoretical isoelectric point of 4.87. Transcription of Pshsp83 appeared from days 1 to 13 post-emergence and peaked at 13th day. Immuno-localization showed that the HSP83 protein was present in cytoplasm of germarium and in egg chambers of the whole ovariole. The transcript abundance of Pshsp83 fluctuated drastically after heat shocks at different temperatures and the maximum emerged at 35°C. The exposure to 35°C caused no dramatic effects on reproductive parameters of adult females such as pupation rate, cocoon weight, emergence rate, sex ratio and developmental duration, but did on longevity. These results suggested that the HSP83 protein is involved in life-span regulation in the P. spretus.
Across the globe, there has been a marked increase in longevity, but significant inequalities remain. These are exacerbated by inadequate access to proper nutrition and health care services and to reliable information to make the decisions related to nutrition and health care. Many in economically developing as well as developed societies are plagued with the double-burden of energy excess and undernutrition. This has resulted in mental and physical deterioration, increased non-communicable disease rates, lost productivity, increased medical costs and reduced quality of life. While adequate nutrition is fundamental to good health at all stages of the life course, the impact of diet on prolonging good quality of life during ageing remains unclear. For progress to continue, there is need for new and/or innovative approaches to promoting health as individuals age, as well as qualitative and quantitative biomarkers and other accepted tools that can measure improvements in physiological integrity throughout life. A framework for progress has been proposed by the World Health Organization in their Global Strategy and Action Plan on Ageing and Health. Here, we focused on the impact of nutrition within this framework, which takes a broad, person-centred emphasis on healthy ageing, stressing the need to better understand each individual's intrinsic capacity, their functional abilities at various life stages, and the impact of their mental, and physical health, as well as the environments they inhabit.
In this paper, we discuss the impact of some mortality data anomalies on an internal model capturing longevity risk in the Solvency 2 framework. In particular, we are concerned with abnormal cohort effects such as those for generations 1919 and 1920, for which the period tables provided by the Human Mortality Database show particularly low and high mortality rates, respectively. To provide corrected tables for the three countries of interest here (France, Italy and West Germany), we use the approach developed by Boumezoued for countries for which the method applies (France and Italy) and provide an extension of the method for West Germany as monthly fertility histories are not sufficient to cover the generations of interest. These mortality tables are crucial inputs to stochastic mortality models forecasting future scenarios, from which the extreme 0.5% longevity improvement can be extracted, allowing for the calculation of the solvency capital requirement. More precisely, to assess the impact of such anomalies in the Solvency II framework, we use a simplified internal model based on three usual stochastic models to project mortality rates in the future combined with a closure table methodology for older ages. Correcting this bias obviously improves the data quality of the mortality inputs, which is of paramount importance today, and slightly decreases the capital requirement. Overall, the longevity risk assessment remains stable, as well as the selection of the stochastic mortality model. As a collateral gain of this data quality improvement, the more regular estimated parameters allow for new insights and a refined assessment regarding longevity risk.
Sexual interaction is an important activity that determines the reproductive schedule of organisms and can ultimately influence the fitness traits of both sexes. Although the influence of sexual interaction on the fitness of females has been extensively determined, little is known about the effects on males, which often have different mating strategies and optimal mating regimes from those of females. To understand how mating regimes (timing and frequency) modulate the fitness in both sexes, we used spider mite (Tetranychus urticae) to investigate the influence of delayed mating and repeated mating on the fitness of male and female. For females, the unmated and the delayed mating females outlived those mated immediately after adult emergence. The repeated mating shortened the lifespan of females that mated at 1-day-old, but not that mated 7-day-old. However, no significant variation in lifespan was observed for males across different mating regimes. We found although delayed mating significantly reduced the daily reproductive rate of the females, there was no significant difference in lifetime reproduction of females across treatments because the delayed mating females increased their reproductive lifespan as a compensation. Our study highlighted that the time and frequency of sexual interaction showed a sex-specific consequence on male and female spider mites, indicating that sexual interaction incurs a higher cost to females which have a much lower optimal mating frequency than males.
Characterizing non-lethal damage within dry seeds may allow us to detect early signs of ageing and accurately predict longevity. We compared RNA degradation and viability loss in seeds exposed to stressful conditions to quantify relationships between degradation rates and stress intensity or duration. We subjected recently harvested (‘fresh’) ‘Williams 82’ soya bean seeds to moisture, temperature and oxidative stresses, and measured time to 50% viability (P50) and rate of RNA degradation, the former using standard germination assays and the latter using RNA Integrity Number (RIN). RIN values from fresh seeds were also compared with those from accessions of the same cultivar harvested in the 1980s and 1990s and stored in the refrigerator (5°C), freezer (−18°C) or in vapour above liquid nitrogen (−176°C). Rates of viability loss (P50−1) and RNA degradation (RIN⋅d−1) were highly correlated in soya bean seeds that were exposed to a broad range of temperatures [holding relative humidity (RH) constant at about 30%]. However, the correlation weakened when fresh seeds were maintained at high RH (holding temperature constant at 35°C) or exposed to oxidizing agents. Both P50−1 and RIN⋅d−1 parameters exhibited breaks in Arrhenius behaviour near 50°C, suggesting that constrained molecular mobility regulates degradation kinetics of dry systems. We conclude that the kinetics of ageing reactions at RH near 30% can be simulated by temperatures up to 50°C and that RNA degradation can indicate ageing prior to and independent of seed death.
The pandemic caused by coronavirus disease 2019 (COVID-19) has forced governments to implement strict social mitigation strategies to reduce the morbidity and mortality from acute infections. These strategies, however, carry a significant risk for mental health, which can lead to increased short-term and long-term mortality and is currently not included in modeling the impact of the pandemic.
We used years of life lost (YLL) as the main outcome measure, applied to Switzerland as an example. We focused on suicide, depression, alcohol use disorder, childhood trauma due to domestic violence, changes in marital status, and social isolation, as these are known to increase YLL in the context of imposed restriction in social contact and freedom of movement. We stipulated a minimum duration of mitigation of 3 months based on current public health plans.
The study projects that the average person would suffer 0.205 YLL due to psychosocial consequence of COVID-19 mitigation measures. However, this loss would be entirely borne by 2.1% of the population, who will suffer an average of 9.79 YLL.
The results presented here are likely to underestimate the true impact of the mitigation strategies on YLL. However, they highlight the need for public health models to expand their scope in order to provide better estimates of the risks and benefits of mitigation.
Iodine intake affects the occurrence of thyroid disorders. However, the association of iodine intake with longevity remains to be described. This led us to perform a 20 years’ follow-up on participants from the Randers–Skagen (RaSk) study. Residents in Randers born in 1920 (n 210) and Skagen born in 1918–1923 (n 218) were included in a clinical study in 1997–1998. Mean iodine content in drinking water was 2 µg/l in Randers and 139 µg/l in Skagen. We collected baseline data through questionnaires, performed physical examinations and measured iodine concentrations in spot urine samples. Income data were retrieved from Danish registries. We performed follow-up on mortality until 31 December 2017 using Danish registries. Complete follow-up data were available on 428 out of 430 of participants (99·5 %). At baseline, the median urinary iodine concentration was 55 µg/l in Randers and 160 µg/l in Skagen residents. Participants were long-term residents with 72·8 and 92·7 % residing for more than 25 years in Randers and Skagen, respectively. Cox regression showed that living in Skagen compared with Randers was associated with a lower hazard ratio (HR) of death in both age- and sex-adjusted analyses (HR 0·60, 95 % CI 0·41, 0·87, P = 0·006), but also after adjustment for age, sex, number of drugs, Charlson co-morbidity index, smoking, alcohol and income (HR 0·60, 95 % CI 0·41, 0·87, P = 0·008). Residing in iodine-replete Skagen was associated with increased longevity. This indicates that long-term residency in an iodine-replete environment may be associated with increased longevity compared with residency in an iodine-deficient environment.
The average productive lifespan is approximately 3 to 4 years in countries with high-producing dairy cows. This is much shorter than the natural life expectancy of dairy cattle. Dairy farmers continue to cull cows primarily for reasons related to poor health, failure to conceive or conformation problems prior to culling. These reasons may indicate reduced welfare leading up to culling. Improvements in health care, housing and nutrition will reduce forced culling related to these welfare reasons. However, productive lifespan has remained similar in decades, despite large improvements in cow comfort and genetic selection for the ability to avoid culling. On the other hand, genetic progress for economically important traits is accelerating within the last decade, which should slightly shorten the average economically optimal productive lifespan. A major driver of productive lifespan is the availability of replacement heifers that force cows out when they calve. The average productive lifespan could be extended by reducing the supply of dairy heifers, which would also have benefits for environmental sustainability. Improvements in culling decision support tools would strengthen economically optimal replacement decisions. In conclusion, major factors of the relatively short productive lifespan of dairy cows are welfare-related, but other economic factors like supply of heifers, genetic progress and non-optimal decision-making also play important roles.
Current research on the psychological health of near-centenarians (95−99 years old) and centenarians remains limited. Existing studies have mainly characterized their physical, cognitive, and social health. Results on the anxiety and depression of near-centenarians and centenarians (more than 95 years old) have been mixed with some studies, finding higher rates of anxiety and depression among those older than 95 years and others reporting no difference in rates compared with younger age groups. This study aims to synthesize the existing literature on the prevalence and predictors of anxiety and depression in near-centenarians and centenarians.
A systematic review was conducted using Ovid Medline, Embase, PsycINFO, CINAHL, SCOPUS, and the Cochrane database. Common and conflicting findings among the literature were examined.
Thirty-eight studies met the inclusion criteria. Six studies examined the prevalence and predictors of anxiety, and 37 studies investigated the prevalence and predictors of depression. Five studies examined both anxiety and depression in the same sample. Prevalence data on anxiety and depression varied significantly, as did comparisons with rates in younger populations. Findings on predictors of anxiety and depression were contradictory.
There is a large degree of heterogeneity among studies of centenarians’ psychological status. Findings conflict on the prevalence and predictors of anxiety and depression and rates compared with younger age groups. Variation in findings may result from the different inclusion criteria, sampling methods, and measurement tools. Better harmonization of centenarian study methodologies may improve consistency of findings to aid in developing clinical interventions.
This chapter looks at insurance standards used to create new markets or reinforce existing ones. It unveils a number of little-known standards that are instrumental in pushing the frontier of highly innovative and securitised insurance markets ever further. It first provides a detailed analysis of the project that insurers, pension schemes and investment banks developed over several years for a standardised solution to pass over to capital markets the risk associated with longer and different expectations in populations’ longevity – known as ‘longevity risk’. Then it shows the significance of standardised data exchange formats in various lines of insurance markets. A case in point is how the world’s largest reinsurers took decades to standardise the exposure to natural hazards risks included in their portfolio. Another one, though not confined to insurance, is the standardised guidelines used for extra-financial reporting and developed by the Global Reporting Initiative (GRI). Evidence gathered in this chapter suggests that, although those standards largely belong to a logic of market creation and rationalisation, compliance remains ambiguous and falls short of a mere transnationalisation of capital accumulation.
The oriental armyworm, Mythimna separata is an important crop pest in eastern Asia. Nocturnal insects, including nocturnal moths, have phototactic behavior to an artificial light source. Phototactic behavior in insects is species-specific in response to different wavelengths of light sources. Our previous study showed that green (520 nm) light emitting diode (LED) light resulted in a significantly higher phototactic behavior in M. separata moths compared to the other wavelength LED lights. The goal of the present study is to investigate the influence of green light illumination on biological characteristics of different developmental stages in M. separata. Our results revealed that when different developmental stages of M. separata were exposed to the green light illumination in a dark period, several biological characteristics in all developmental stages except for egg stage were positively changed, but those of F1 generation M. separata which are next generation of the adults exposed to the green light did not significantly change compared with the control level. These findings suggest that green light illumination at night (or dark period) has a positive effect on the development and longevity of M. separata.
The aim of this study was to gain an understanding of the experiences of extended longevity as perceived by centenarians. Centenarians (people over 100 years of age) are the fastest growing group of the ageing population in developed countries. Ten centenarians aged between 100 and 106 years, living in the Lower North Island of New Zealand, participated in the study. The biographical narrative interpretive method of inquiry guided data collection through face-to-face interviews, and thematic analysis was subsequently undertaken. Four themes were identified: (a) ‘becoming a centenarian: ‘Just another day’; (b) ‘growing up in a privileged environment’ that revealed four sub-themes: ‘having freedom and choice’, ‘being loved and nurtured’, ‘living healthy lifestyles’ and having ‘good education prospects’; (c) ‘unique opportunities in adult life’; and (d) ‘positive ageing and celebration of longevity’. The centenarians spoke nonchalantly about their experience of turning 100 and positive personalities were prominent features of the participants, who all expressed a sense of acceptance and satisfaction with life and contentment with living in the present, a feature throughout their lives that was ongoing and at an intergenerational level. This study has provided further insights into the existing literature on longevity and through the narratives of the centenarians has demonstrated the value of Erikson's psycho-social stages of development and Tornstam's theory of gerotranscendence when considering positive ageing.
Longevity is one of the most important traits determining dairy cow profitability. In the last decades dairy cows suffered a lowering in the age at culling. With the aim to identify the genes involved in longevity, dates of birth, yields, dates of calving during lifespan and culling dates were collected for 946 culled cows which had been genotyped with the Bovine High Density panel. Using the GenABEL package in R, genome-wide association analysis was performed on three potential traits of longevity: (1) ‘days in production,’ (2) ‘days in herd,’ (3) number of calvings over lifespan.’ Five genome-wide significant single nucleotide polymorphisms (SNPs) associated with all three longevity traits were detected. Several consecutive SNPs identified on chromosomes 16 and 30 indicated the presence of two suggestive quantitative trait loci (QTL). The genes comprised in the QTL regions had biological functions related to fertility, reproductive disorders, heat stress and welfare of cows. These findings might contribute to improving breeding strategies to improve longevity.
The present study investigated the population dynamics of Hepatus pudibundus in the Cananéia region, in southern São Paulo state, Brazil, focusing on population structure, growth parameters, longevity, sex ratio, reproduction and recruitment juvenile period. Sampling was performed monthly at seven stations from July 2012 to June 2014, using a shrimp fishing boat. A total of 1650 specimens were collected: 551 males and 1099 females. The males were larger than females. Reproductive females were captured throughout the study period and juveniles were captured in most months. Both of these demographic categories were positively correlated with temperature. Growth parameters showed differences between sexes: CW∞ = 78.91 mm, k = 0.0066 day−1, t0 = 0.0965 for males and CW∞ = 69.71 mm, k = 0.0053 day−1, t0 = −0.2404 for females. Longevity was estimated at 1.91 and 2.40 years for males and females, respectively. The findings provide a greater understanding of the life cycle in this species. Additionally, since trawl nets are not selective, this study also provides information for better trawl fishery management, addressing not only the target shrimp but also the by-catch species.
Probiotics are bacteria among the intestinal flora that are beneficial for human health. Bifidobacterium longum (BL) is a prototypical probiotic that is widely used in yogurt making, supplements and others. Although various physiological effects of BL have been reported, those associated with longevity and anti-ageing still remain elusive. Here we aimed to elucidate the physiological effects of killed BL (BR-108) on stress tolerance and longevity of Caenorhabditis elegans and their mechanisms. Worms fed killed BL in addition to Escherichia coli (OP50) displayed reduced body length in a BL dose-dependent manner. When compared with those fed E. coli alone, these worms had a higher survival rate following heat stress at 35°C and hydrogen peroxide-induced oxidative stress. A general decrease in motility was observed over time in all worms; however, killed BL-fed ageing worms displayed increased movement and longer life span than those fed E. coli alone. However, the longevity effect was suppressed in sir-2.1, daf-16 and skn-1-deficient worms. Killed BL induced DAF-16 nuclear localisation and increased the expression of the DAF-16 target gene hsp-12.6. These results revealed that the physiological effects of killed BL in C. elegans were mediated by DAF-16 activation. These findings contradict previous observations with different Bifidobacterium and Lactobacillus strains, which showed the role for SKN-1 independently of DAF-16.