Dissertations / Theses on the topic 'Longevity'

An increased risk or a history of cardiovascular disease (CVD) is associated with worse survival prospects. Clinical guidelines recommend several treatments for primary and secondary prevention. These guidelines are mainly based on clinical trials and hospital data. Data from routine clinical practice could provide insights in longevity and longevity improvement in the general population as opposed to selected patients. The primary objectives of this research were to investigate how a history of CVD affects longevity in residents of the United Kingdom at retirement age, and to investigate which treatments improve longevity. Medical records from 1987 to 2011 from general practices contributing to The Health Improvement Network (THIN) database were used to develop two specific survival models: to estimate the hazards of all-cause mortality associated with a history of acute myocardial infarction (AMI) and related treatments, and to estimate the hazard of all-cause mortality associated with statins prescribed as primary prevention of CVD. The models were multilevel Cox's proportional hazards regressions that included comorbidities, treatments, lifestyle choices, and socio-demographic factors. The models were specified for ages 60, 65, 70, and 75. More accurate estimates of longevity at these key ages could inform future medical management by clinicians and financial planning for retirement by individuals, actuaries, and the government. This research found that survival prospects after AMI were reduced by less than previous studies have reported. Furthermore, currently recommended treatments for CVD were associated with mixed survival prospects, in which coronary revascularisation and prescription of beta blockers and statins were associated with improved prospects and prescription of ACE inhibitors and aspirin were associated with worsened prospects.

L'elaborato si propone di analizzare il fenomeno dell'invecchiamento della popolazione e di spiegare cos'è il rischio di longevità, su quali soggetti può avere un impatto significativo e quali modelli possono essere utilizzati per una sua corretta misurazione.

Public schools are facing a leadership crisis regarding the lack of women superintendents in the United States. Although, historically, women have dominated the positions of classroom teachers and outnumbered men in receiving administrative leadership certificates, there is a disproportion in the number of men and women superintendents leading the nation's approximate 14,000 public schools. While current researchers describe the complex roles that the superintendency entails, there is little data on gender differences, specifically, how women superintendents achieve longevity in this role. The purpose of this study was to examine the relationship between the longevity of women superintendents in public school districts and perceived barriers that may influence longevity, using the human relations approach as a theoretical guide. Data were collected using a qualitative, multiple case study of 5 women superintendents, with longevity of at least 6 years, via survey and interview. Data were analyzed for general and emergent themes and related to 3 research questions regarding perceived barriers and longevity. Findings indicated a shift in the perception of barriers over the last 2 decades, with important issues surrounding relationships and possible self-imposed barriers. The women superintendents were no longer worried about breaking the glass ceiling or competing with their male counterparts. Rather, they were concerned with balancing professional and personal responsibilities while maintaining positive relationships at school and at home. Social change may result by addressing perceived barriers of women superintendents to achieve longevity and gender equity. As a result, female perspectives and insights, which have been historically neglected and omitted, may be included in more local and national policy decision-making in educational administration.

Les espècies més longeves han evolucionat disminuint la producció endògena d’espècies reactives d’oxigen i proveint-se d’estructures resistents a la oxidació. Per tant, aquelles espècies que viuen més gaudeixen de mitocòndries metabòlicament més eficients i estructuralment més estables. De fet, característiques fenotípiques de la longevitat inclouen la reducció del contingut del complex I i dels aminoàcids sulfurats. Aleshores, l’activitat de determinades vies de senyalització intracel·lulars juga un paper clau regulant l’expressió de gens associats a un fenotip longeu. En aquest context, aquesta tesi pretén determinar i) la modulació de determinades subunitats del complex I associada a la longevitat; ii) els canvis en el contingut dels aminoàcids sulfurats i els seus intermediaris metabòlics en teixits post-mitòtics i iii) plasma d’espècies més longeves; iv) la regulació del contingut dels diferents elements específics del complex 1 de mTOR en termes de longevitat; i v) l’existència un perfil metabòlic associat a humans de longevitat extrema. Els resultats obtinguts mostren l’existència de perfils metabòlics associats a la longevitat de les espècies que, en alguns casos, són diferents a aquells perfils associats a la longevitat individual. A més, les espècies més longeves han evolucionat disminuint el contingut de determinades subunitats del complex I que podrien ésser responsables de la menor producció d’espècies reactives d’oxigen. Per altra banda, existeixen factors genètics que podrien determinar l’activitat basal de mTORC1, i que podrien, almenys en part, explicar el fenotip associat a la longevitat. Per tant, sembla que l’assoliment d’una major longevitat implica una adaptació metabòlica i estructural.
Las especies más longevas han evolucionado disminuyendo la producción endógena de especies reactivas de oxígeno y proveyéndose de estructuras resistentes a la oxidación. Por lo tanto, aquellas especies que viven más disfrutan de mitocondrias metabólicamente más eficientes y estructuralmente más estables. De hecho, características fenotípicas de la longevidad incluyen la reducción del contenido del complejo I y de amino ácidos sulfurados. Por lo tanto, la activad de determinadas vías de señalización intracelular juegan un papel clave regulando la expresión de genes asociados a un fenotipo longevo. En este contexto, esta tesis pretende determinar i) la modulación de determinadas subunidades del complejo I asociada a la longevidad; ii) los cambios en el contenido de amino acido sulfurados y de sus intermediarios metabólicos en tejidos post-mitóticos y iii) plasma de especies más longevas; iv) la regulación del contenido de distintos elementos específicos del complejo 1 de mTOR en términos de longevidad; y v) la existencia de un perfil metabólico asociado a humanos de longevidad extrema. Los resultados obtenidos muestran la existencia de perfiles metabólicos asociados a la longevidad de las especies que, en algunos casos, son diferentes a aquellos perfiles asociados a la longevidad individual. Además, las especies más longevas han evolucionado disminuyendo el contenido de determinadas subunidades del complejo I que podrían ser responsables de la menor producción de especies reactivas de oxígeno. Por otra parte, existen factores genéticos que podrían determinar la actividad basal de mTOR, y que podrían, al menos en parte, explicar el fenotipo asociado a la longevidad. Por lo tanto, parece que lograr una mayor longevidad implica una adaptación metabólica y estructural.
Long-lived species have evolved by decreasing the rate of endogenous reactive oxygen species production and providing them of oxidation-resistant structures. Hence, species that live longer benefit from metabolically efficient and structurally stable mitochondria. In fact, phenotypic traits of longevity include reduced content of complex I and sulphur-containing amino acids. Then, the activity of selected intracellular signalling pathways plays a key role regulating the expression of genes associated to a longevity phenotype. In this context, this thesis aims to determine i) the modulation of specific complex I subunits associated to longevity; ii) the changes on sulphur amino acids content and its metabolic intermediates in post-mitotic tissues and ii) plasma from long-lived species; iv) the content regulation of the different mTOR complex 1 specific forming elements in terms of longevity; and v) the existence of a metabolic profile associated to human extreme longevity. The obtained results reveal the existence of metabolic profiles associated to species longevity that, in some cases, differ from those profile associated to individual longevity. Furthermore, longer lived species have evolved reducing the content of specific complex 1 subunits that might be responsible for the limited reactive oxygen species production. Otherwise, genetic factors that might determine the basal activity of mTORC1 exist, and that could, at least In part, explain the longevity associated phenotype. Thus, it seems that the achievement of an extended longevity implies a metabolic and structural adaptation.

Doutoramento em Economia
Saving for retirement is a decision that depends on many factors. Firstly, it depends on the disposable income and future expected income. Secondly, the composition of households and the ages of individuals are determinant. Thirdly, it depends on the composition of net wealth and, finally, longevity during working life and retirement period. The life-cycle theory explains the consumption and saving decisions in function of the different phases in life. During childhood, the individual consumes and receives his education. In a second stage, the individual actively consumes, produces and saves. In a third phase, the individual uses his accumulated net wealth, including the amount of social security wealth, to finance his consumption of life-cycle during retirement. The social models ensure a substitution income and access to benefits in every stage of life, causing an impact on consumption and saving decisions. In this dissertation, saving behaviour is analysed by considering the impact of longevity in different countries representative of the various European Social Models, i.e. Sweden (Nordic Model), France (Continental Model), Portugal (Mediterranean Model) and the UK (Anglo-Saxon Model).
Epargner pour la retraite est une décision qui dépend du revenu disponible comme du revenu espéré futurement, de la composition des ménages et les âges des individus, de la richesse nette accumulée et, finalement, de la longévité durant l'âge actif et pendant la période de la retraite. La théorie du cycle de vie explique les décisions de consommation et l'épargne en fonction des phases de la vie de l'individu. Dans une première phase, (en occurrence l'enfance), l'individu consomme et reçoit son éducation. Dans une seconde phase, d'activité professionnelle), l'individu produit, consomme et épargne. Dans une troisième phase, celle de la retraite, l'individu utilise sa richesse nette accumulée pendant la période d'activité incluant la richesse provenante de la sécurité sociale pour financer sa consommation du cycle de vie. Les modèles sociaux assurent le remplacement du revenu et l'accès à des prestations dans toutes les phases de la vie de l'individu et influencent les décisions de consommation et d'épargne. Dans cette thèse, le comportement de l'épargne est analysé en prenant en compte la longévité dans les différents pays représentatifs des modèles sociaux européens, notamment, la Suède (Modèle Nordique), la France (Modèle Continental), le Portugal (Modèle Méditerranéen) et le Royaume-Uni (Modèle Anglo-Saxon).

Master of Science
Department of Food, Nutrition, Dietetics and Health
Jennifer Hanson
Longevity, and factors that may increase the human lifespan, have been the topic of many research studies attempting to pinpoint direct positive influences. Research demonstrates that among those who live beyond an average life expectancy, approximately 25% of the increased lifespan is related to genetics. The remaining 75% is largely due to environmental factors, mainly diet and lifestyle factors, that have the ability to influence genetic effects for increased longevity. The following types of studies on diet and lifestyle factors for increasing longevity and decreasing the incidence of chronic conditions were reviewed: Prospective cohorts, longitudinal, in vitro, randomized controlled trials, and prospective case-controlled studies. Results related to the Mediterranean Diet were consistent in the conclusion that adherence to this diet increased the lifespan and delayed the development of chronic conditions although calorie restriction demonstrated an increase in longevity, the studies examined failed to correlate this diet to the reduced incidence of disease development. Red meat and alcohol consumption, though both are considered carcinogenic, demonstrated some benefits to the elderly. However, both need to be consumed with caution as they may negatively impact health when consumed outside of moderation. Physical activity demonstrated a consistent benefit to the elderly by increasing longevity and decreasing age-related conditions. Epigenetic research consistently concluded that a diet high in antioxidants and healthy fats both increase telomere length and decrease DNA damage though the exact mechanism remains unknown. Studies on the impact of regular social interactions and time spent on leisure activities in advanced age are consistent in the conclusion that both contribute to health and well-being in this demographic group, but failed to connect to an increase in longevity.

Epargner pour la retraite est une décision qui dépend du revenu disponible comme du revenu espéré futurement, de la composition des ménages et les âges des individus, de la richesse nette accumulée et, finalement, de la longévité durant l’âge actif et pendant la période de la retraite. La théorie du cycle de vie explique les décisions de consommation et l’épargne en fonction des phases de la vie de l’individu. Dans une première phase, (en occurrence l’enfance), l’individu consomme et reçoit son éducation. Dans une seconde phase, (l’activité professionnelle), l’individu produit, consomme et épargne. Dans une troisième phase, celle de la retraite, l’individu utilise sa richesse nette accumulée pendant la période d’activité incluant la richesse provenant de la sécurité sociale pour financer sa consommation du cycle de vie. Les modèles sociaux assurent le remplacement du revenu et l’accès à des prestations dans toutes les phases de la vie de l’individu et influencent les décisions de consommation et d'épargne. Dans cette thèse, le comportement de l’épargne est analysé en prenant en compte la longévité dans les différents pays représentatifs des modèles sociaux européens, notamment, la Suède (Modèle Nordique), la France (Modèle Continental), le Portugal (Modèle Méditerranéen) et le Royaume-Uni (Modèle Anglo-Saxon)
Saving for retirement is a decision that depends on many factors. Firstly, it depends on the disposable income and future expected income. Secondly, the composition of households and the ages of individuals are determinant. Thirdly, it depends on the composition of net wealth and, finally, longevity during working life and retirement period. The life-cycle theory explains the consumption and saving decisions in function of the different phases in life. During childhood, the individual consumes and receives his education. In a second stage, the individual actively consumes, produces and saves. In a third phase, the individual uses his accumulated net wealth, including the amount of social security wealth, to finance his consumption of life-cycle during retirement. The social models ensure a substitution income and access to benefits in every stage of life, causing an impact on consumption and saving decisions. In this dissertation, saving behaviour is analysed by considering the impact of longevity in different countries representative of the various European Social Models, i. E. Sweden (Nordic Model), France (Continental Model), Portugal (Mediterranean Model) and the UK (Anglo-Saxon Model)

In questo lavoro si utilizzano processi affini a diffusione per valutare alcuni tipici contratti assicurativi. Ci si concentra poi nella valutazione ad età avanzate per vedere in che modo il longevity risk può essere tenuto in considerazione anche in vista degli standards valutativi.

Thesis (M.A.)--Georgia State University, 2008.
Title from file title page. Frank J. Whittington, committee chair; Elisabeth O. Burgess, Toshi Kii, committee members. Electronic text (189 p. : col. ill.) : digital, PDF file. Description based on contents viewed Sept. 17, 2008. Includes bibliographical references (p. 177-180).

The 20th century has witnessed some of the largest and most widespread gains in human longevity ever witnessed, which show no sign of slowing down during the early years of the 21st century. The risk of further, higher than anticipated improvements in life expectancy - known as longevity risk - is now a major and growing field of study. This thesis investigates a number of theoretical and practical problems within the field of longevity risk relating to the structure and identifiability issues within many of the most common models used to study mortality rates, the construction of new mortality models, the projection of these models into the future, the impact of differences in the level and evolution of mortality rates in different populations (such as pension schemes) and the market-consistent valuation and measurement of risk in longevity-linked liabilities and securities.

Since their divergence from a common ancestor some 200 million years ago, mammals have undergone significant diversification in physiology, morphology, habitat, size, and longevity. The maximum lifespan of mammalian species ranges from under 3 to over 200 years, but the molecular basis of such variation is poorly understood. While many genes, pathways, dietary interventions, and pharmacological compounds have been shown to influence the lifespan of model organisms, it is not known whether the same mechanisms are responsible for the longevity variation across different species. This thesis presents the analyses of gene expression and the levels of metabolites, chemical elements, and/or proteins, across multiple organs and tissues of up to 42 species of mammals, as well as the analyses of 5 long-lived mouse models, 22 natural isolates of yeast, and 16 species of fruit flies, to identify the molecular patterns and signatures associated with species longevity. The results show that longer-lived mammals up-regulate ribosomal proteins and genes involved in DNA repair, and down-regulate ubiquitin-mediated proteolysis and apoptotic functions. Some of the metabolic changes in long-lived mammals, such as higher levels of sphingomyelins and glycerophospholipids but lower levels of polyunsaturated triacylglycerols, were also observed in long-lived mouse models. Yeast strains of varying replicative lifespan differed in their aerobic respiration capacity, attributable to different protein composition in mitochondria. Long-lived fruit flies overexpressed the genes involved in lipid metabolism but suppressed the genes involved in neuronal development. Many genes previously implicated in lifespan control in model organisms also showed the expected correlation with the longevity traits across species. This thesis presents the snapshots of the complex changes associated with species natural lifespan variation and offers new insights into the mechanisms of longevity control and potential lifespan extension strategies.
Medical Sciences

Cette thèse s’intéresse à la relation de long-terme entre la longévité et le développement économique. Dans le premier chapitre, j’analyse l’impact des dépenses de santé sur la croissance et le bien-être. Pour cela, j’étudie l’influence du taux d’imposition dans une économie avec temps de vie endogène (Chakraborty (2004)). Je détermine le taux d’imposition qui maximise le taux de croissance. Puis je m’intéresse aux variations du niveau de production dans l’état stationnaire par rapport au taux d’imposition. Enfin, j’étudie le taux d’imposition qui maximise le bien-être dans l’état stationnaire. Dans le second chapitre, j'analyse l’impact sur la croissance de dépenses de santé choisies par les agents. En effet, je développe un modèle de croissance endogène dans lequel les individus peuvent dépenser des ressources pour vivre plus longtemps dans leur période de retraite. Je donne une caractérisation complète de l’équilibre général dynamique puis je détermine l’impact sur la croissance des dépenses de santé. Enfin, le troisième chapitre étudie l’impact théorique du vieillissement sur l’allocation sectorielle des travailleurs. Je développe un modèle multi-sectoriel dans lequel j’examine les conséquences sur le revenu par travailleur et l’allocation sectorielle des travailleurs d’un choc de longévité et de fertilité. Je montre que contrairement aux modèles uni-sectoriels, le revenu n’est pas forcément monotone par rapport aux variables démographiques. Des chocs démographiques réalistes produisent des mouvements non-négligeables de travailleurs
This dissertation is interested in the long-run relationship between longevity and economic development. In the first chapter, I analyse the impact of health expenditures on economic growth and welfare. For this, I study the influence of the tax rate in an economy à la Chakraborty (2004). I first determine the growth-maximizing tax rate, which is shown to be 0 in low-income countries. Second, I show that the steady-state income level is an inverted U-shaped function or a decreasing function of the tax rate. Third, I study the tax rate that maximizes the steady-state welfare level. In the second chapter, I propose a theoretical model to study the growth impacts of health expenditures chosen by the agents. Indeed, I develop a Diamond model with endogenous growth in which young individuals can spend resources to increase their longevity in retirement period. I give a full characterization of the dynamic general equilibrium and determine the growth impacts of health expenditures. They can speed up or slow down economic growth. They can be a barrier or a necessity for growth to take place. A calibration to OECD countries suggests that the latter case is the most likely one. Finally, the third chapter studies the theoretical impact of the aging process on the sectorial labor allocation. To this aim, I develop a multi-sector two-period overlapping generations model in which I examine the consequences of both a longevity shift and a fertility shift on the labor allocation of the economy and on the income per worker level. I show that contrary to one-sector models, the income per worker level is not necessarily monotonic with respect to demographic variables. Realistic demographic shocks are also shown to create significant labor reallocation across sectors

Data from the Quebec swine breeding program (1980 to 2001) were used to estimate genetic parameters for longevity and to evaluate the contribution of non-genetic factors. After data verifications, there were 28,377 Yorkshire, 30,123 Landrace and 7,830 Duroc sows with records of herd life. The program 'The Survival Kit V3.12' (Ducrocq and Solkner, 2001) was used to estimate heritability separately within each breed, using a Cox proportional hazard model. The time-independent fixed effects of age at first service and of the combinations of herd with year of birth, estimated breeding value (EBV) backfat, EBV age to 100 kilograms and EBV litter size were included. The effects of number of piglets born, number of piglets weaned, crossbreeding at insemination, stage of sow (farrowing, weaning or heat) and their combination with parity were treated as fixed time-dependent variables whereas herd by year was treated as random time-dependent variable. The random effect of sire using sire relationships back two generations was considered as the source of genetic variation. Length of productive life (longevity) was defined as the number of days from first service until culling.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 2002.
Includes bibliographical references.
Aging is a universal process that affects organisms from yeast to humans. Replicative life span in the budding yeast, Saccharomyces cerevisiae is defined as the number of daughter cells produced by a mother cell prior to senescence. The isolation and characterization of genes and interventions that extend mother cell life span can provide insight into the mechanisms of aging. One cause of aging in yeast is the accumulation of extrachromosomal ribosomal DNA circles (ERCs) in the mother cell nucleus. ERCs are formed by homologous recombination within the ribosomal DNA (rDNA) caused by the presence of a stalled replication fork. Mutation of the replication fork block protein Foblp dramatically reduces ERCs and extends life span. A central regulator of longevity in yeast is the silencing protein Sir2p. Deletion of SIR2 shortens life span and overexpression of SIR2 extends life span. Sir2p promotes silenced chromatin at the rDNA by catalyzing a novel NAD-dependent histone deacetylation reaction. This rDNA silencing function is likely to promote long life span by inhibiting rDNA recombination and, hence, the formation of ERCs. Sir2p is required for life span extension by caloric restriction (CR), demonstrating the important role that this protein plays in the aging process. CR is thought to activate Sir2p by increasing the amount of NAD that is available as a substrate for Sir2p. The finding that osmotic stress extends life span by a mechanism that genetically mimics CR supports this. High osmolarity causes a metabolic shift from fermentation to an NAD-generating glycerol biosynthesis pathway.
(cont.) Life span extension by high osmolarity requires both Sir2p and glycerol biosynthesis. SSD1-V defines the only known Sir2p independent pathway that promotes long life span. SSD1-V functions in many different cellular processes and the mechanism(s) by which it extends life span is not known. SSDI-V functions in a pathway parallel to the longevity promoting protein Mpt5p for cell integrity and interacts genetically with the aging gene UTH1 in several, apparently unrelated, cellular processes. Further defining the molecular nature of this Sir2p-independent longevity pathway will provide insight into the aging process in yeast and, perhaps, higher organisms as well.
by Matt Kaeberlein.
Ph.D.

Mestrado em Actuarial Science
Atualmente, as entidades gestoras de fundos de pensões têm mostrado alguma preocupação em relação ao risco dos seus participantes viverem mais do que o inicialmente esperado, assim como em relação ao impacto desta situação nas reservas mantidas pelos fundos para pagamento de pensões a partir da reforma. Não é novidade para quem trabalha nesta área de negócios que as taxas de mortalidade têm vindo a decrescer nos últimos anos a um ritmo acelerado. Esta tendência é motivada pelas melhorias na área da saúde, avanços tecnológicos e na capacidade das empresas e consultores financeiros de anteciparem este risco e limitar os seus efeitos, Não existindo um mercado real para monitorizar e calcular o risco atribuído ao fato da população viver até mais tarde, várias pesquisas têm vindo a ser conduzidas de modo a conseguir gerir melhor este risco, ao qual chamamos risco de longevidade. Este trabalho explora o risco de longevidade no mercado de fundo de pensões do Reino Unido, no contexto de um estágio curricular numa grande consultora internacional, e introduz modelos estocásticos estudados no passado, relacionando os mesmos com algumas ferramentas e software relevantes. O principal objetivo deste relatório foi estudar as transações usadas tipicamente para gerir o risco de longevidade. Uma aplicação de um dos modelos estocásticos usando o software R é também usada para o propósito desta análise, assim como para estimar os parâmetros do modelo e usar os resultados como uma possível ilustração.
It is no news to anyone in this industry that mortality rates have been decreasing faster year by year. Such a trend is driven by health improvements, technological advances, and the ability of firms and investment advisers to anticipate risk and limit its effects. Since there is no real market per say to monitor or calculate that risk attributed with people living longer, research has been extensively conducted to manage such risk. This risk is called longevity risk and it directly affects the mortality assumptions set by the team of actuaries conducting a valuation. In this paper we explore longevity risk in the UK pension fund market, in the context of an internship at a major consultancy, and introduce stochastic based models that have been studied in the past, relating these to some relevant tools and software. We emphasize the importance of managing this risk and present innovations in recent years that are related to longevity risk. Several investment techniques / financial products are introduced within the research paper. The focus of this paper was on the transactions that are used typically to manage longevity risk. An application of one of the stochastic models is used using R software package for the purpose of our analysis, so as to estimate the parameters for that model and use the results as a possible illustration.
info:eu-repo/semantics/publishedVersion

Du contexte de vieillissement démographique en Europe, dont sa prévalence et sa généralisation au continent européen le rendent inédit et sans précédent, découle un certain nombre de problématiques. Ainsi, l’augmentation du nombre de personnes âgées, et plus particulièrement, du nombre de personnes âgées en situation de dépendance démocratise la question de leur prise en charge et du rôle de chacune des parties prenantes. Cette thèse se propose d’étudier les problématiques relatives au vieillissement et à l’offre d’aide informelle. Le premier Chapitre étudie la relation entre mortalité et revenu. Le deuxième Chapitre s’intéresse aux motivations des enfants à devenir les aidants informels de leurs parents. Les troisième et quatrième Chapitres analysent, respectivement, l’impact de l’aide informelle sur la santé de l’aidant et celle de son partenaire
In a context of population ageing, the number of people requiring long-term care (LTC) is expected to increase. This fast growing old-age population is mainly cared informally, either by family members or close relatives. This thesis aims at contributing to the existing knowledge about ageing and informal care. The first Chapter examines the relationship between longevity and income in European countries. In Chapter 2, we study the incentives of adult children to care their old-age parents. Chapter 3 and Chapter 4 address, respectively, the consequences of the decision to care on both caregivers’ health as well as on the caregivers ‘ couple

Conscientiousness is positively associated with health and longevity. Evidence has suggested that conscientiousness can influence health via engagement in health behaviours. More recently, research has focussed upon alternative pathways through which conscientiousness may convey its desirable effects. Questionnaire methods were utilised to examine the association between conscientiousness and health behaviours (study 1). Behavioural intention was explored as a mediator of the conscientiousness–fruit and vegetable consumption relationship, with results indicating that behavioural intention fully mediated the relationship. Conscientiousness was also shown to predict health behaviour guideline adherence, when health behaviours were examined independently and simultaneously (study 2). Findings indicated greater levels of adherence in individuals high in conscientiousness. Factor analysis revealed that the items employed to measure the facets of industriousness, order, self-control, virtue and traditionalism are reliable and represent separate lower order facets of conscientiousness. Meanwhile, the items employed to measure the facet of responsibility require revision. Study 3 assessed psychological and physiological reactivity in response to stress in individuals with different levels of conscientiousness. Differential effects were seen between the conscientiousness groups, and primary appraisals were identified as being important for dealing with anticipated stress physiologically. Daily diaries and multi-level modelling were employed to assess the effects of daily hassles on unhealthy between-meal snacking in individuals high and low in conscientiousness (study 4). An implementation intention based intervention was also delivered, and experimental condition and conscientiousness were assessed as moderators of the daily hassle–unhealthy snacking association. Conscientiousness was shown to moderate the relationship with a greater association seen between daily hassles and unhealthy snacking in individuals low in conscientiousness. Condition also moderated this relationship, with individuals assigned to the active control condition consuming fewer unhealthy snacks on more stressful days. This thesis has provided evidence to support the roles of behavioural intention and stress in the conscientiousness-health association, and has highlighted multiple relations between these factors.

Strategies to promote active aging and counteract the development of age-related diseases are among the most challenging researches in the framework of Horizon 2020, accordingly with the World Health Organization's declaration that "increased longevity without quality of life is an empty prize”. The aim of this thesis is to investigate the role of blood circulating microRNAs (miRs) and their expression profile characterizing aging and longevity trajectories, and particularly to distinguish between healthy and unhealthy longevity. To this purpose two experimental designs were defined, the former applied the advanced technology of smallRNA-sequencing (Illumina platform) to screen circulating miRs in a small cohort of different aged people, the latter was based on selected miRs analyzed on a larger cohort. The protocol for sequencing analysis, including library preparation, was optimized and applied on 12 donors, i.e. 3 young healthy donors, 3 old healthy donors, 3 healthy centenarians and 3 unhealthy centenarians. Significant miRs identified by sequencing, i.e. miR-30a-5p, -766-3p, -598-3p, were measured on a larger cohort of 48 subjects. Aging-related miRs previously described, i.e. miR-133a-3p, -206, -16, were analyzed in the same cohort of 48 donors. Circulating miR-206 and miR-16 levels described significant trajectories of aging, while miR-598-3p and miR-133a-3p levels characterized longevity trajectories. All these miRs are involved in the PI3K-Akt signaling, a central pathway for aging process. Finally, blood circulating molecules able to distinguish between healthy and unhealthy were obtained by joining the identified miRs and hemato-biochemical parameters, opening the possibility for further studies on therapeutic approaches.

Strategies to promote active aging and counteract the development of age-related diseases are among the most challenging researches in the framework of Horizon 2020, accordingly with the World Health Organization's declaration that "increased longevity without quality of life is an empty prize”. The aim of this thesis is to investigate the role of blood circulating microRNAs (miRs) and their expression profile characterizing aging and longevity trajectories, and particularly to distinguish between healthy and unhealthy longevity. To this purpose two experimental designs were defined, the former applied the advanced technology of smallRNA-sequencing (Illumina platform) to screen circulating miRs in a small cohort of different aged people, the latter was based on selected miRs analyzed on a larger cohort. The protocol for sequencing analysis, including library preparation, was optimized and applied on 12 donors, i.e. 3 young healthy donors, 3 old healthy donors, 3 healthy centenarians and 3 unhealthy centenarians. Significant miRs identified by sequencing, i.e. miR-30a-5p, -766-3p, -598-3p, were measured on a larger cohort of 48 subjects. Aging-related miRs previously described, i.e. miR-133a-3p, -206, -16, were analyzed in the same cohort of 48 donors. Circulating miR-206 and miR-16 levels described significant trajectories of aging, while miR-598-3p and miR-133a-3p levels characterized longevity trajectories. All these miRs are involved in the PI3K-Akt signaling, a central pathway for aging process. Finally, blood circulating molecules able to distinguish between healthy and unhealthy were obtained by joining the identified miRs and hemato-biochemical parameters, opening the possibility for further studies on therapeutic approaches.

Nella tesi consideriamo i principali fattori che influenzano l'andamento demografico dei paesi industrializzati e ne descriviamo le implicazioni per i sistemi pensionistici. Dopo una descrizione dei principali modelli di mortalità stocastica utilizzati in letteratura, analizziamo due datasets e scegliamo i migliori in termini di adattamento ai dati e proiezioni future. Vengono impostati due diversi problemi di massimizzazione. Il primo considera un consumatore che deve massimizzare l'utilità del proprio consumo e delle somme che riceverà alla data di pensionamento in un contesto in cui sono presenti due sistemi pensionistici (il PAYG ed un funded puro). Il problema viene risolto mediante il metodo di Bellman. Il secondo considera un consumatore che massimizza l'utilità del consumo durante l'intera vita lavorativa e può scegliere l'istante di pensionamento. Anche nel secondo problema sono considerati due sistemi pensionistici. Il problema è risolto tramite il metodo della martingala.
In the thesis we describe the common factors of evolution for the populations of the most industrialized countries. We describe the implications in terms of pension sustainability. We describe the most used stochastic mortality models and find the most suitable models in terms of fitting and forecasting for two different datasets. We set two maximization problems. In the first we find the optimal mix between the pay-as-you-go (PAYG) and funded pension systems for a consumer who wants to maximize the inter-temporal utility of his/her consumption during the working life and the utility of the lump sums obtained at the retirement time. The solution is obtained via Bellman's approach. In the second problem we find the optimal retirement time for a consumer who wants to maximize his/her consumption during the entire life and can choose between the aforementioned pension systems. The solution is obtained via martingale approach.

Ageing and senescence remain among the most intriguing questions in biology. Saccharomyces cerevisiae has become well established as a fertile model system for the investigation of ageing. Remarkable conservation has been found to exist between interventions extending lifespan in higher animals and yeast – genetic, chemical, and nutritional – suggesting a network of common regulatory pathways controlling large-scale shifts in gene expression involved in senescence. While it has been proposed that epigenetic regulation controls these shifts, evidence remains incomplete. To address this question, novel longevity mutants were isolated in S. cerevisiae using a purpose-designed high-precision screen based on ageing culture outgrowth. A novel long-lived mutant in uncharacterised gene YDR026C was discovered and found to participate in a pathway distinct from TOR signalling, but share epistasis with the histone deacetylase SIR2Δ, a well established regulator of replicative longevity and rDNA maintenance. Through equilibrium density centrifugal separation of culture subpopulations, SIR2Δ and Ydr026cΔ cultures were found to demonstrate reduced and improved maintenance of post-diauxic quiescence respectively, previously shown to underlie chronological survival in strains including snf1Δ. Development of a quantified TUNEL-based assay for genome fragmentation indicated early apoptotic-like behaviour in the SIR2Δ strain. Microdissection experiments and sectored-colony assays of strains containing an rDNA-embedded ADE2 reporter determined that Ydr026cΔ cells also exhibit extended replicative lifespan, and reduced recombination at the rDNA spacer region hotspot, abrogated in SIR2Δ strains. SIR2Δ is well established to repress RNA polymerase II-derived transcripts in the rDNA spacer region, including IGS1-R. Northern analysis determined Ydr026c also silences transcription in the spacer, possibly through preventing termination of the main rRNA transcript, interfering with IGS1-R expression. By transformation with a vector overexpressing IGS1-R, partial reconstitution of the SIR2Δ phenotype was observed, including rDNA hyperrecombination, shortened replicative longevity, and higher-order chromatin structure restoration. These data suggests a model whereby non-coding rDNA spacer transcripts epigenetically determine rDNA maintenance through recombination, leading to physiological phenotypes of replicative and chronological ageing.

Mestrado em Ciências Empresariais
Many family firms find it difficult to reach their fourth generation; nevertheless, these firms have some features that may help them to achieve success and longevity. This thesis tries to identify some critical issues that often prevent family companies to survive over time and tries to analyse how family company Jerónimo Martins could overcome obstacles and achieved success and longevity through a good management of the interference of the family sphere in the work sphere.
Muitas empresas familiares têm dificuldade em atingir a quarta geração. No entanto, estas empresas têm algumas características que podem ajuda-las a alcançar o sucesso e a longevidade. Esta tese tenta identificar algumas questões críticas que muitas vezes impedem as empresas familiares de sobreviver ao longo do tempo e tenta analisar como a empresa familiar Jerónimo Martins conseguiu ultrapassar obstáculos e alcançar o sucesso e a longevidade através de uma boa gestão da interferência da esfera familiar na esfera do trabalho.

Mestrado em Actuarial Science
Este trabalho foi desenvolvido com três objetivos principais: (i) fazer o survey da situação atual, no que diz respeito à mortalidade/longevidade no nosso país; (ii) desenvolver um estudo breve sobre os progressos registados na mortalidade em Portugal, com base num projeto semelhante apresentado por Assia Billing, no encontro da Primavera do Mortality Working Group da International Actuarial Association (Berlim, 2018) - grupo que se dedica ao estudo da mortalidade a nível mundial, dando particular atenção ao impacto que esta tem sobre o sector segurador, nomeadamente o ramo de Vida e Pensões; (iii) servir como suporte ao primeiro Country Report português, a ser divulgado pelo Mortality Working Group. No decorrer do trabalho, e tendo em vista os três objetivos estabelecidos, irão ser primeiramente analisados indicadores demográficos, como a evolução da população residente portuguesa, a sua pirâmide populacional, o índice de envelhecimento e a esperança de vida. Numa segunda parte, o foco incidirá sobre o sector segurador português, com a análise de indicadores como a produção ou a composição dos portfolios de investimento. Seguidamente, faz-se a análise dos produtos mais vendidos em Portugal, por tipo de contrato. No que diz respeito às tábuas de mortalidade, merecem destaque as que são publicadas anualmente pelo INE, bem como as que são mais utilizadas nas seguradoras que operam no território nacional. Finalmente, desenvolver-se-á a análise dos progressos registados mais recentemente a nível da mortalidade no país, na senda de estudos similares desenvolvidos para outros países.
This work was developed with three main objectives: (i) to survey the current situation, regarding mortality/longevity in Portugal; (ii) to develop a brief study on the progress of mortality in the country, based on a similar project presented by Assia Billing in the Spring Meeting (Berlin 2018) of the International Actuary Association Mortality Working Group ? a group that is dedicated to the study of mortality worldwide, paying particular attention to the impact it has on the insurance sector, namely on Life and Pensions ; (iii) to serve as support for the first Portuguese Country Report to be released by the Mortality Working Group,. In the course of the study, demographic indicators, such as the evolution of the Portuguese resident population, the population pyramid, the aging index and the life expectancy, will be analyzed first. Then, the focus will be set on the Portuguese insurance sector, with the analysis of indicators such as the production or the composition of investment portfolios. Next, we analyze Portugal?s mostly sold insurance products, by type of contract. Regarding the mortality tables, it is worth mentioning those published annually by INE, as well as those that are most used by insurers operating in the national territory. Finally, an analysis of the most recent progress in mortality in the country will be performed, following similar studies developed for other countries.
info:eu-repo/semantics/publishedVersion

Un nouveau gène de la longévité ouvre de nouvelles pistes pour vieillir mieux. L'accroissement de la longévité induit par la suppression des tissus reproducteurs a été observé chez la drosophile et chez le ver. Chez ce dernier, l'opération lui donne 60% de vie en plus et lui permet un vieillissement harmonieux et en bonne santé. Les mécanismes moléculaires qui induisent cette réponse font l'objet d'intenses recherches. Certains gènes étaient déjà connus pour être associés à l'accroissement de la longévité des vers sans lignée germinale, et nous avons démontré l'existence d'une nouvelle voie impliquant le récepteur nucléaire NHR-80. Les nématodes dépourvus de lignée germinale et dont nhr-80 est muté ne voient pas leur longévité augmenter. En outre, la surexpression du gène allonge davantage leur durée de vie: elle est 150% plus longue que celle de leurs congénères sauvages. Cela démontre l'importance de ce récepteur nucléaire dont l'activation par une hormone encore inconnue enclenche l'expression ou la mise sous silence de centaines d'autres gènes. Notamment, nous avons montré que l'une des cibles de NHR-80, l'enzyme FAT-6 qui transforme l'acide stéarique en acide oléique est fondamentale, puisque les vers dépourvus de lignée germinale ne présentent plus aucun gain en longévité en l'absence de FAT-6. À terme, nous espérons pouvoir récapituler les effets de l'ablation de la lignée germinale chez un organisme fertile, c'est à dire, d'induire les réarrangements métaboliques qui ont lieu suite à cette opération afin d'en tirer les effets positifs sur la santé, sans affecter la reproduction
Discovery of a key longevity gene opens new perspectives for healthy aging.Increased longevity induced by reproductive tissues removal (germline ablation) is observed in the fly Drosophila melanogaster and in the worm Caenorhabditis elegans. In the latter, the operation increases lifespan by 60%, and enables the nematode to age harmoniously and in good health. The molecular mechanisms that induce this response are subject of intensive research. Our study reveals the existence of a new powerful longevity gene, nhr-80, which mediates this longevity effect. We have shown that inactivation of nhr-80 prevents lifespan increase. Furthermore, nhr-80 overexpression lengthens the nematodes' lifespan by 150%! nhr-80 encodes a nuclear receptor, which activation by a still unknown hormone controls the expression of hundreds of other genes. We showed that one of the critical NHR-80 targets, the enzyme FAT-6, which transforms stearic acid into oleic acid, is necessary to prolong lifespan since a mutation of the fat-6 gene suppresses the effects of germline ablation on longevity. The next step will be to determine how an increase in the level of oleic acid induces an adaptive response resulting in increased longevity. This research may lead to the exciting possibility of recapitulating the benefits of germline ablation in fertile animals; in other words, to activate the longevity effects normally triggered by germline ablation in order to fight, in one go, a host of diseases associated with aging, without affecting reproduction

Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2003.
Includes bibliographical references (leaves 258-273). Also available in electronic version. Access restricted to campus users.

Reactive oxygen species (ROS), and the resulting oxidative stress caused by these species, have long been attributed to be one of the causes for aging and age related disorders. NADPH, the reduced form of nicotinamide adenine dinucleotide phosphate (NADP), provides a critical and essential buffer against cellular toxicity due to ROS. NADPH is one of the cells most powerful reducing agents, capable of regenerating other endogenous antioxidants such as glutathione from its oxidized form, glutathione disulfide. Consequently, it is hypothesized that declining NADPH levels with age results in a depletion in cellular capacity to respond to ROS induced damage, further accelerating the aging process. To study the importance of NADPH on the aging process as well as the molecular mechanisms involved, lifespan assays were performed using knockdown of various enzymes involved in the production of NADPH in Caenorhabditis elegans. Preliminary results indicate declining NADPH levels do have an effect on expected longevity. More interesting however, is a possibly important distinction between cytoplasmic and mitochondrial enzymes involved in the production of NADPH. These preliminary results suggest the existence of a previously undescribed molecular mechanism that is potentially important to the aging process. However, further experiments and analysis are required to further elucidate these mechanisms and to confirm preliminary findings.

Cette thèse a démontré que les athlètes élites vivent en moyenne 7 ans de plus que la population générale, notamment en raison d’une réduction de 35 à 45% de la mortalité par maladies cardiovasculaires et par cancers. Ces résultats s’appuient sur l’analyse de l’ensemble des sportifs français (n= 3.600) ayant participé aux Jeux Olympiques depuis 1912 et au Tour de France depuis 1947. Des nouvelles méthodes en analyse de survie ont été mises au point pour investiguer ces cohortes qui ont la particularité de survivre mieux que leurs référents. A ces démonstrations s’ajoute le ralentissement de la progression de la longévité maximale humaine. Ce constat résulte de la comparaison des tendances de durée de vie de tous les olympiens depuis 1896 (n= 19.012) et des doyens de l’humanité (n= 1.205). Ces travaux répondent au besoin de mieux comprendre la relation dose-réponse de l’activité physique, médicament du 21ème siècle, en raison de son impact majeur sur la longévité des populations, ainsi qu’à l’intérêt d’explorer les marges d’augmentation possibles de cette longévité
Background and objectives: along their careers, elite athletes are subjected to specific constraints that distinguish them from the general population. Such constraints, related to the high intensity of their physical activity, their overexposure to injuries or particular lifestyle, may have long-term consequences on the athletes' health, and ultimately on their longevity. Thus, the main goals of the present study are the following: 1) to describe and analyze elite athletes’ longevity and specific causes of mortality in comparison with the general population and according to the type of effort they performed; and 2) to investigate their lifespan trends in comparison with the longest-lived humans in order to apprehend the current scenario of human longevity trends. Methods: we collected data on the biography and the athletic performances of all the French athletes who participated in the Olympic Games (OG) from 1912 to 2012 (n = 4708), and all the French cyclists who participated in the Tour de France (TDF) from 1947 to 2012 (n=786). Then, we verified their vital statuses through the National Registry of Identification of Physical Persons (RNIPP). For the deceased athletes, we obtained the causes of their deaths through the Centre for epidemiology on medical causes of death (CépiDc). We compared the athletes’ overall and specific mortality (according to the main chapters of the International Classification of Disease) with the French civilian life tables using Standardized Mortality Ratio (SMR) and the Kaplan-Meier methods. We adapted and applied the life years-lost method under the competing risk model to quantify differences on longevity due to major causes of death according to the athletes’ type of effort. Furthermore, we collected data on worldwide deceased Olympians participating in the OG from 1896 to 2012 (n=19 012) and on worldwide supercentenarians (>110 years) deceased between 1900 and 2013 (n= 1 205) in order to analyze their lifespan trends using a density analysis tool (total number of life durations per birth date). Findings and conclusion: French elite athletes show consistently lower mortality (≈40-50% lower) in comparison with their compatriots, whether female or male Olympians, or professional cyclists, mostly related with a lower cardiovascular (≈ 40-60% lower) and cancer mortality (≈ 45% lower). No excess mortality was observed in elite athletes for any of the specific causes of death we studied. French Olympians’ lower mortality results in an average of seven years of life saved in relation to the general population. This gain partitioned according to specific causes of deaths shows that cardiovascular longevity benefit is associated with the type of sports practiced during the Olympic career, favoring combined type of effort over very short- or very long-duration effort. In relation to cancer mortality, all types of effort studied were associated with better longevity. Despite their survival advantage, no Olympian in the world, up to date, has ever reached the status of a supercentenarian, as the longest-lived was 106 years old. The common lifespan trends between Olympians and supercentenarians indicate similar mortality pressures over both populations that increase with age, a scenario that is better explained by a biological “barrier” limiting further progression. The supercentenarians’ density trends show a current stagnation of the human longevity

Seed longevity has been investigated predominantly in relation to taxonomic and macroclimatic differences, while little is known about the variation within closely related taxa, growing under the same climate. Therefore, seed longevity of 18 alpine species Asteraceae was compared using artificial ageing (AA) to ascertain the influence of seed and species-specific ecological traits (i.e. seed mass, soil pH and moisture) on seed longevity. The estimates of p50 (estimate the time for viability to fall to 50 %) ranged between 1.63 and 40.03 d. Soil moisture significantly influenced seed longevity, with seeds of species growing on dry soil showing higher p50 than those from wetter soil. Conversely, seed mass and soil pH did not significantly contribute to longevity differences across species, though species from acid soils tend to be shorter lived than those from basic soils. Plant ecological traits, linked to condition at the plant growing site may play crucial roles in the prediction of seed lot longevity in air-dry storage including seed bank conditions. Germination test by means of radicle protrusion is often used as an assessment of seed viability (i.e. seed longevity studies). Therefore, there is a possibility that radicle protrusion alone may over-estimate viability compared with normal germination (i.e. radicle plus cotyledon emergence), thereby seed longevity. However, the extent of such overestimation across species and the factors contributing to it are not yet well understood. Therefore, seed life span of 35 alpine species was studied by evaluating both radicle emergence and normal germination during artificial ageing (AA). Estimates of p50 based on radicle emergence (p50 (RE)) were significantly higher than estimates based on normal germination (p50 (NG)) in 18 (51.4 %) out of the 35 species tested, suggesting radicle emergence may not be a reliable indicator of the capacity of seeds to complete the germination process, thereby leading to an overestimation of seed longevity. Therefore, in accordance with these results, the actual seed longevity of several alpine species may be lower than previously reported, highlighting that ex situ storage of alpine seeds might be even more problematic than currently thought. The coefficient of OESL developed here and its correlates (i.e. seed type, soil pH and seed longevity) may be used to prioritize species’ vulnerability to ex situ storage and to optimize viability testing, thereby reducing labour costs and enabling more effective conservation of seed collections. Alpine species are short-lived and most of them are incapable of becoming a seedling. Therefore, long-term storage of these species could be a problematic even under conventional seed banking conditions. As a solution, seed priming can be used to increase both seed longevity and seedling recovery. Therefore, I investigated the potential for priming to increase the longevity of six alpine species using a range of water potentials (hydro and osmo-priming). According to this study, priming treatments had a significant positive effect on seed longevity (p50 (RE) and p50 (NG)). In particular, hydro-priming was the most successful seed priming treatment to enhance both p50 (RE) and p50 (NG) and decreased the overestimation. The information provided in this study on wild alpine plants may fill some knowledge gap about how to monitor and improve seed viability in storage, which may have important implications high quality seeds both long- and short-term ex situ storage, such as in seed banks and native seed industry, respectively. In particular, I highlighted that normal germination (i.e. radicle plus cotyledon emergence) should be used to monitor seed viability during storage, that species from more humid soil may have higher possibility to show short-lived seeds and that, alpine seeds are short-lived, their longevity can be significantly improved using easy and inexpensive techniques, such as hydro and osmo-priming.
Seed longevity has been investigated predominantly in relation to taxonomic and macroclimatic differences, while little is known about the variation within closely related taxa, growing under the same climate. Therefore, seed longevity of 18 alpine species Asteraceae was compared using artificial ageing (AA) to ascertain the influence of seed and species-specific ecological traits (i.e. seed mass, soil pH and moisture) on seed longevity. The estimates of p50 (estimate the time for viability to fall to 50 %) ranged between 1.63 and 40.03 d. Soil moisture significantly influenced seed longevity, with seeds of species growing on dry soil showing higher p50 than those from wetter soil. Conversely, seed mass and soil pH did not significantly contribute to longevity differences across species, though species from acid soils tend to be shorter lived than those from basic soils. Plant ecological traits, linked to condition at the plant growing site may play crucial roles in the prediction of seed lot longevity in air-dry storage including seed bank conditions. Germination test by means of radicle protrusion is often used as an assessment of seed viability (i.e. seed longevity studies). Therefore, there is a possibility that radicle protrusion alone may over-estimate viability compared with normal germination (i.e. radicle plus cotyledon emergence), thereby seed longevity. However, the extent of such overestimation across species and the factors contributing to it are not yet well understood. Therefore, seed life span of 35 alpine species was studied by evaluating both radicle emergence and normal germination during artificial ageing (AA). Estimates of p50 based on radicle emergence (p50 (RE)) were significantly higher than estimates based on normal germination (p50 (NG)) in 18 (51.4 %) out of the 35 species tested, suggesting radicle emergence may not be a reliable indicator of the capacity of seeds to complete the germination process, thereby leading to an overestimation of seed longevity. Therefore, in accordance with these results, the actual seed longevity of several alpine species may be lower than previously reported, highlighting that ex situ storage of alpine seeds might be even more problematic than currently thought. The coefficient of OESL developed here and its correlates (i.e. seed type, soil pH and seed longevity) may be used to prioritize species’ vulnerability to ex situ storage and to optimize viability testing, thereby reducing labour costs and enabling more effective conservation of seed collections. Alpine species are short-lived and most of them are incapable of becoming a seedling. Therefore, long-term storage of these species could be a problematic even under conventional seed banking conditions. As a solution, seed priming can be used to increase both seed longevity and seedling recovery. Therefore, I investigated the potential for priming to increase the longevity of six alpine species using a range of water potentials (hydro and osmo-priming). According to this study, priming treatments had a significant positive effect on seed longevity (p50 (RE) and p50 (NG)). In particular, hydro-priming was the most successful seed priming treatment to enhance both p50 (RE) and p50 (NG) and decreased the overestimation. The information provided in this study on wild alpine plants may fill some knowledge gap about how to monitor and improve seed viability in storage, which may have important implications high quality seeds both long- and short-term ex situ storage, such as in seed banks and native seed industry, respectively. In particular, I highlighted that normal germination (i.e. radicle plus cotyledon emergence) should be used to monitor seed viability during storage, that species from more humid soil may have higher possibility to show short-lived seeds and that, alpine seeds are short-lived, their longevity can be significantly improved using easy and inexpensive techniques, such as hydro and osmo-priming.

Thesis (M.A.)--Georgia State University, 2007.
Title from file title page. Heying Jenny Zhan, committee chair; Frank J. Whittington, Yong Tai Wang, committee members. Electronic text (67 p. : col. ill.) : digital, PDF file. Description based on contents viewed Nov. 7, 2007. Includes bibliographical references (p. 61-67).

A new modeling method for estimation of the longevity of infiltration system was suggested in this study. The model was one-dimensional, based on results from long-term infiltration sites in Sweden, taking some physical and chemical parameters as controlling factors. It defines the longevity of infiltration systems as the time during which the P solution in effulent is under national criteria (1 mg/L in this study), and it aims at providing the longevity for any given point of the infiltration system. The soil in the model was assumed to be totally homogenous and isotropic and water flow was assumed to be unsaturated flow and constant continuous inflow. The flow rate was calculated from the Swedish criteria for infiltration systems. The dominant process in the model would be the solute transport process; however, retardation controlled by sorption would play a more important role than advection and dispersion in determining the longevity in the model. By using the definition of longevity in this study, the longevity of the three soil columns at 1 m depth (Knivingaryd, Ringamåla and Luvehult) were 1703 days, 1674 days and 2575 days. The exhaustion time of the three soil columns under inflow of 5 mg/L were 2531 days, 2709 days and 3673 days. The calculated sorbed phosphorus quantity for soil from sites Kn, Lu and Ri when they reach estimated longevity were 0.177, 0.288 and 0.168 mg/g, while the maximum sorption of Kn, Lu and Ri were 0.182, 0.293 and 0.176 mg/g separately. From the result of sensitivity study of the model, the sorption capacity and flow velocity were most important to the longevity of the infiltration system. Lower flow velocity and higher P sorption capacity extend the longevity of an infiltration bed. Due to the sorption isotherm selected in this study and the assumption of instant equilibrium, the sorption rate of the soil column was quite linear, although the estimated longevity was much shorter than the real exhaustion time of the soil column. In fact the soil has almost reached its sorption maximum when the system reaches its longevity.

The main objective of this research was to determine the seed bank longevity of Melinis repens at two Southern Florida sites. Seeds were divided among different exposure levels (shade versus sun) and depths (surface versus buried) and tested for baseline viability using 2,3,5-Triphenyl-tetrazolium chloride. Statistical analysis determined that at the pine rockland site there was a significant interaction between time, exposure, and depth. The initial mean viability at this site declined from 49.71% to 11.26% and 13.06% for sun/buried seeds and sun/surface seeds, respectively, by month 8. The mean viability of shade/surface seeds and shade/buried seeds declined to 24.56% and 22.06% after 8 months. There were no significant effects in the Florida scrub. In order for land managers to completely remove this species from a site, treatment with herbicide will need to continue for a minimum of one year to effectively kill all viable seeds in the seed bank.

Roots and their associated mycorrhizal fungi have long been recognised as major determinants of nutrient cycling. Their measurement has been limited because soil limits accessibility. The use of in-situ camera techniques in conjunction with minirhizotrons and image analysis software now make the acquisition of accurate root longevity data possible. The current literature was reviewed in relation to root longevity - both measurement techniques and available data. Four main experiments were employed to study the root longevity of a number of tree species, grass and clover subject to differing environmental conditions and grass and clover and poplar roots with and without colonisation by Arbuscular Mycorrhizal fungi. The data was analysed in a number of different ways including the use of the powerful statistical technique for censored data - survival analysis. This technique proved to be very useful for analysing temporal changes to root longevity. The data indicate that root longevity can be extremely short but is dependent upon environment and for some species, colonisation by Arbuscular Mycorrhizal fungi. Preliminary calculations were completed to determine the role of root death in nutrient cycling and these predict that large quantities of nitrogen, phosphorus and carbon are flowing from the live to the dead root pool on an annual basis.

We are currently in the midst of a revolution in ageing research, with several dietary, genetic and pharmacological interventions now known to modulate ageing in model organisms. Whilst it has been known for almost 100 years that dietary restriction (DR) extends lifespan across wide evolutionary distances, the mechanisms through which it acts are still unknown. Using three different recombinant inbred ILSXISS mouse strains, which vary in response to DR; from lifespan extension to lifespan shortening, my PhD has sought to identify the mechanisms involved in DR-induced lifespan extension. Ultimately by exploiting the genetic heterogeneity of these mouse strains may help identify the mechanisms through which DR acts to slow ageing. During my PhD I (1) examined how these animals respond metabolically to DR, (2) determined the impact of DR on mitochondrial function, as mitochondrial dysfunction is a well characterised hallmark of ageing, and DR is known to attenuate age-related mitochondrial dysfunction, and (3) investigated proteostasis in these mice using isotopic labelling. A number of metabolic changes were found to be important to lifespan extension with DR, namely maintenance of gonadal white adipose tissue (WAT) stores and increases in brown adipose tissue (BAT). Conversely, large losses of WAT was associated with lifespan truncation following 40% long-term DR. Surprisingly, enhanced glucose homeostasis was not found to be a prerequisite to lifespan extension with DR. Hepatic mitochondrial dysfunction associated with reduced lifespan of TejJ114 mice under 40% DR, but similar dysfunction was not apparent in skeletal muscle mitochondria, highlighting tissue-specific differences in the mitochondrial response in ILSXISS mice to DR. Increased proteostasis as measured by the newprotein/newDNA ratio, was increased following short-term DR, highlighting increased synthesis of cytoplasmic proteins in the skeletal muscle as important to DR-induced lifespan extension, however results were both tissue and protein specific. The evidence produced in this thesis strongly suggests that numerous aspects of metabolism and mitochondrial function are associated with lifespan shortening, and that the inability for metabolic adaptability may be detrimental to lifespan. This thesis helps to elucidate the impact of genotype on key hallmarks of DR and highlights the importance of utilising both genders and genetically heterogeneous murine strains in order to understand the shared features of slowed ageing.

[EN] The global objective of the present thesis was to study the functional longevity defined as length of productive life (LPL) in five Spanish specialized lines of rabbit (A, V, H and LP). Chapter 3, aimed to check the genetic heterogeneity for longevity between the five lines estimating the additive variance and the corresponding effective heritabilities. As well as to test the genetic importance of time-dependent factors such as positive palpation order (OPP), physiological status (PS) and number of kits born alive (NBA) on the genetics of longevity. This point has been assessed using four different Cox proportional hazard models; the first one (Model 1) included all the previous factors in addition to the year-season effect, the inbreeding coefficient effect and finally the animal effect as random factor. The remaining three models were the same as Model 1 but excluding OPP (Model 2), or PS (Model 3), or NBA (Model 4). The complete data set comprised 15,670 does with records 35.6 % having censoring data, and the full pedigree file involved 19,405 animals. The heritability estimates for longevity in the five lines were low and ranged from 0.02±0.01 to 0.14±0.09, and consequently, it is not recommended to include this trait as selection criteria in rabbit breeding programs. Despite of the large variation of the heritability estimates, the corresponding HPD95% always overlapped and consequently the hypothesis of all lines having the same heritability cannot be discarded. Comparing the additive variance estimates of the four models, it was observed that by correcting for PS 51, 39, 38, 83 and 75% of the additive variance in lines A, V, H, LP and R, respectively, was removed. The risk of death or culling decreases as OPP advanced. Non-pregnant-non-lactating females are those under the higher risk. The does which had zero NBA had the highest risk, apart for this special figure (zero NBA) the risk decreased as NBA increased. Chapter 4 intended to estimate the genetic and environmental correlations between longevity and two prolificacy traits (number of kits born alive (NBA) and number of kits alive at weaning (NW)). Furthermore, to estimate the genetic and environmental correlations between longevity and the percentage of days that the doe spent in the different physiological statuses with respect to its entire productive life. The complete pedigree file comprised 19,405 animals. The datasets included records on 15,670 does which had 58,329 kindlings and 57,927 weanings. In general the genetic correlations between NBA and NW, and the hazard were low to very low, and the only line for which it can be said these genetic correlation to be different from zero was the LP line. Regarding the correlations between longevity and the percentage of days the doe spent in each physiological status, there were evidences of non-negligible genetic correlations between the two traits. Chapter 5 purposed to compare the five lines at their foundation and at fixed time periods during their selection programs. The first comparison was done at the origin of the lines, involving the complete data set, and using a genetic model (CM) including the additive values of the animals, so the effect of selection was considered. For the second comparison the same model as the first comparison was used, but excluding the additive effects from the model of analysis (IM), and involving only the data corresponding to each period, so the differences between the lines included the additive values of the animals. The lines V, H and LP showed at foundation a substantial superiority over line A. The line R had higher risk of death or culling with relevant differences when compared to V, H and LP lines. The maximum relative risks were observed between the lines LP and R (0.239), and between LP and A (0.317). For the comparisons at fixed times, the pattern of the differences between the A line and the others was similar to those observed at foundation.
[ES] El objetivo global de la presente tesis fue estudiar la longevidad funcional en cinco líneas españolas de conejos (A, V, H y LP), el carácter se definió como la longitud de la vida productiva. En el Capítulo 3, dirigido a comprobar la heterogeneidad genética de la longevidad entre las 5 líneas, se estimaron las varianzas aditivas y sus correspondientes heredabilidades efectivas. Y además se evaluó la importancia del orden de la palpación positiva (OPP), el estado fisiológico (PS) y el número de gazapos nacidos vivos (NBA) sobre el determinismo genético de la longevidad. Para ello se utilizaron 4 modelos de Cox de riesgos proporcionales; el primer modelo (Modelo 1) incluyó todos los factores anteriores, además del efecto del año-estación, el efecto de la consanguinidad y, finalmente, el valor aditivo de los animales como efecto aleatorio. Los otros tres modelos fueron igual que el Modelo 1 pero excluyendo OPP (Modelo 2), o PS (Modelo 3), o NBA (Modelo 4). Los datos de longevidad estaban referidos a 15,670 conejas y tuvieron una tasa de censura de 35.6%. La genealogía completa involucró a 19,405 animales. Las estimas de heredabilidad efectiva para la longevidad en las 5 líneas fueron bajas y variaron de 0.02±0.01 a 0.14±0.09. A pesar de la gran variación de las estimas puntuales de heredabilidad, los correspondientes intervalos HPD95% siempre se solaparon y por lo tanto la hipótesis de que todas las líneas tengan la misma heredabilidad no pudo descartase. Se observó que la exclusión de PS incrementó la varianza aditiva aproximadamente, en un 51, 39, 38, 83 y 75% en las líneas A, V, H, LP y R, respectivamente. El riesgo de muerte o eliminación disminuía a medida que avanzaba el OPP, observándose el riesgo más alto durante los primeros dos partos, partos en los que las conejas todavía están creciendo lo que sería un factor de riesgo importante. El nivel No-Gestante-No-Lactante de PS tuvo el mayor riesgo. Este nivel se interpreta como indicador de baja fertilidad y/o problemas de salud de la coneja. Las conejas que tenían cero NBA tuvieron el mayor riesgo de muerte o eliminación, aunque para el resto de niveles de NBA se apreció una disminución del riesgo a medida que aumenta la prolificidad. En el capítulo 4, se estimaron las correlaciones genéticas y ambientales entre la longevidad y dos caracteres de prolificidad [número de gazapos nacidos vivos (NBA) y el número de destetados (NW)]. El fichero de datos incluyó 58,329 partos y 57,927 destetes. También se estimaron las correlaciones entre longevidad y el porcentaje de días que la coneja pasó en los diferentes estados fisiológicos con respecto a la totalidad de su vida productiva. La única línea para la que se puede decir que la correlación genética entre NBA o NW y el riesgo fue significativamente diferente de cero fue la línea LP. Hubo evidencias de correlaciones genéticas no despreciables entre la longevidad y el porcentaje de días que la hembra pasó en cada estado fisiológico los dos caracteres. En el capítulo 5 se compararon las longevidades medias de las 5 líneas en su fundación y en períodos de tiempo determinados. La comparación de las líneas en el origen, utilizó todos los datos y un modelo genético (CM) que incluía los valores aditivos de los animales. Para la comparación en tiempos fijos se utilizó el mismo modelo, pero excluyendo los efectos aditivos del modelo de análisis (IM), utilizando sólo los datos correspondientes a cada período, por lo que las diferencias entre las líneas incluían los cambios debidos a la selección. Las líneas V, H y LP mostraron una superioridad sustancial sobre las líneas A y R. Los riesgos relativos máximos se observaron entre las líneas LP y R (0.239), y entre LP y A (0.317). Con respecto a las comparaciones en tiempos fijos, el patrón de las diferencias entre la línea de A y las otras líneas fue similar a los observados en la fundación.
[CAT] L'objectiu global de la present tesi va ser estudiar la longevitat funcional en cinc línies espanyoles de conills (A, V, H i LP), el caràcter es va definir com la longitud de la vida productiva. Al Capítol 3, dirigit a comprovar l'heterogeneïtat genètica de la longevitat entre les 5 línies, es van estimar les variàncies additives i les seues corresponents heretabilitats efectives. A més a més, es va avaluar la importància de factors dependents del temps, com l'orde de la palpació positiva (OPP) , l'estat fisiològic (PS) i el nombre de llorigons nascuts vius (NBA) sobre el determinisme genètic de la longevitat. Per a això es van utilitzar 4 models de Cox de riscos proporcionals; el primer model (Model 1) va incloure tots els factors anteriorment assenyalats, a més de l'efecte de l'any-estació, l'efecte de la consanguinitat i, finalment, el valor additiu dels animals com a efecte aleatori. Els altres tres models van ser igual que el Model 1 però excloent l'OPP (Model 2) , o PS (Model 3) , o NBA (Model 4) . Les dades de longevitat estaven referides a 15,670 conilles i van tindre una taxa de censura de 35.6%. La genealogia completa va involucrar a 19,405 animals. Les estimes d'heretabilitat efectiva (Model 1) per a la longevitat en les 5 línies van ser baixes i van variar de 0.02±0.01 a 0.14±0.09. A pesar de la gran variació de les estimes puntuals d'heretabilitat, els corresponents intervals HPD95% sempre es van solapar i per tant la hipòtesi que totes les línies tinguen la mateixa heretabilitat no va poder descartar-se. Es va observar que l'exclusió de PS va incrementar la variància additiva, aproximadament, en un 51, 39, 38, 83 i 75% en les línies A, V, H, LP i R, respectivament. El risc de mort o eliminació disminuïa a mesura que avançava l'OPP, observant-se el risc més alt durant els primers dos parts, en què les conilles encara estan creixent el que seria un factor de risc important. El nivell No-Gestant-No-Lactant de PS va tindre el major risc en comparació amb els altres nivells. Les conilles que tenien zero NBA van tindre el major risc de mort o eliminació, encara que per a la resta de nivells de NBA es va apreciar una disminució del risc a mesura que augmentà la prolificitat. Al Capítol 4, es van estimar les correlacions genètiques i ambientals entre la longevitat i dos caràcters de prolificitat [nombre de llorigons nascuts vius (NBA) i el nombre de deslletats (NW)]. El fitxer de dades va incloure 58,329 parts i 57,927 deslletaments. L'única línia per a la que es pot dir que la correlació genètica entre NBA o NW i el risc va ser significativament diferent de zero va ser la línia LP. Evidències de correlacions genètiques no menyspreables entre longevitat i els percentatge de dies que la femella va passar en cada estat fisiològic. Al Capítol 5 es compararen les longevitats mitges de les 5 línies en la seua fundació i en períodes de temps determinats. Per a la comparació de les línies a l'origen, es van utilitzar totes les dades i un model genètic (CM) que incloïa els valors additius dels animals, per la qual cosa es va considerar l'efecte de la selecció a partir de la fundació. En la comparació en temps fixos se va utilitzar el mateix model que en l'anterior, però excloent els efectes additius del model d'anàlisi (IM), utilitzant només les dades corresponents a cada període, per la qual cosa les diferències entre les línies incloïen els canvis deguts a la selecció. Les línies V, H i LP van mostrar una superioritat substancial sobre les línies A i R. Els riscos relatius màxims es van observar entre les línies LP i R (0.239), i entre LP i A (0.317). Respecte a les comparacions en temps fixos, el patró de les diferències entre la línia de A i les altres línies va ser semblant als observats en la fundació.
El Nagar, AGF. (2015). Genetic analysis of longevity in specialized lines of rabbits [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/52390
TESIS