Dissertations / Theses on the topic 'Ecology of aging'

As animals age, they are expected to invest successively more energy in reproduction as they have fewer subsequent chances to reproduce (the “restraint” hypothesis). Conversely, the oldest animals may show restraint in reproduction because even a small increase in energy expended during reproduction may lead to death. Alternatively, both young and very old animals may lack the ability to maintain high levels of energy expenditure (the “constraint” hypothesis), leading to reduced reproductive success. Many studies have observed an increase in reproductive success with age followed by a reduction at the end of life, but fewer studies have examined the proximate mechanisms, which provide a context for understanding ultimate causes. I examined over 30 behavioural and physiological metrics of aging in two species of free-living long-lived seabirds (thick-billed murres Uria lomvia and black-legged kittiwakes Rissa tridactyla) and a short-lived passerine (tree swallows Tachycineta bicolor). For all species, reproductive success was high at intermediate ages. In support of the “restraint” hypothesis, when birds were stressed glucocorticoid hormones, which direct energy away from reproduction and towards survival, were higher in young birds (swallows) and both young and very old birds (kittiwakes and murres). When birds were handicapped older birds expended more energy. When challenged exogenously, there was no change in hormone levels with age, implying that they were “choosing” to be restrained. Resting metabolic rate (RMR) declined linearly with age in both seabird species. T3, which I show is indicative of RMR in birds, also declined with age, demonstrating that the reduction in metabolism was strategic and not due to changing body composition. In contrast, daily energy expenditure in both seabird species during breeding was constant with age while antioxidant capacity became elevated during middle age, and further increased with age. Several measures of behavioural performance did not vary with age. I conclude that hormonal cues lead to greater investment in adult’s energy stores over its offspring’s energy reserves (restraint hypothesis) at the start of life. At the end of life, both hypotheses were supported; energy expenditure was constrained by senescence, leading to increased restraint in investing additionally in offspring.

Aging is a degenerative process characterized by a decline in physiological functions and cellular activities. Environmental and pharmacological interventions affecting longevity pathways have been extensively studied in model organisms. This study investigated the effect of chronic mild intermittent hypoxia (4 mg O2/L) or mild mitochondrial uncoupling with three doses of 0 (control), 0.1, 1, and 5 μM of 2,4-Dinitrophenol (DNP), on life history and gene expression in four clones of Daphnia magna. Interestingly, clones from intermittent ponds displayed better tolerance to hypoxia and DNP. Although neither treatments extended longevity, hypoxia increased fecundity and body size, and decreased food consumption and respiration rate. We uncovered 12 candidate genes that were differentially expressed in hypoxia-tolerant and sensitive clones in response to hypoxia. Unexpectedly, DNP increased fecundity and mitochondrial membrane potential without affecting food intake. This work opens up an opportunity for genomic determination of the potentially important phenotypes in a model organism.

In recent years, tremendous growth in the older adult population has prompted the US Federal government along with state governments to fund programs and organizational structures that can help meet the needs of older adults. Further, organizations such as the National Council on Aging, as well as the American Association of Retired Persons (AARP), and nonprofits such as the United Way also partner in these efforts. This project seeks to analyze the content of American state and federal policy as well as nonprofit programs in order to identify the policy priorities that are currently being supported. Do current policy efforts promote “aging in place” strategies as a way to maintain quality of life and older adult health? An analysis of public policies and nonprofit program structures in the United States since 2000 will help to identify policy priorities that impact aging adults, and will hopefully pave the way to prepare our society for further actions and needs in order to continue to serve them in the next several decades.

Ageing women have so often been represented in government policy rhetoric, gerontology literatures and journalistic discourse as the genderless, powerless and passive objects of welfare and services;, by and large, as a social problem that needs to be monitored and managed. Taking a cultural research approach, this thesis explores ageing women’s actual practices in Hong Kong social movements and aims to rerepresent ageing women as active social agents capable of generating multiple “tactical identities” enabling them to participate in and interact with an environment that poses concrete challenges to their participation. In filling the gap between research on social movements and in social gerontology, both massively studied areas but ones whose mutual interactions are rare, this thesis reviews the social participations of three women at their late 60s and early 70s, who have been actively involved around issues of involuntary removal in public housing, and in health care and rent issues. The research explores how ageing women have used the notions of “Old Hong Kong” and “Old residents” - a rhetoric long bound up with their life histories in Hong Kong—to create a ‘mask of ageing’ in negotiation and interaction with the authorities, with neighbours, their community and, most importantly, their children. On the other hand, by acting as mothers, as grandmothers and as the “po po” (older woman in Cantonese) living next door, ageing women in effect compose collectives and form networks in their community to support their independent mode of living. The thesis argues that a new politics of ageing which addresses the everyday realities of ageing women’s lives is essential if we are to offer an alternative interpretation of their ageing experiences.

Climate change will lead to higher temperatures and longer summers in the future, which will likely influence the growing season of fish living in temperate lakes. The warm summer of 2018 in Sweden matches prognoses for normal summers at the end of the century and can thus be used to investigate the effect of temperature related factors on fish growth. In this study I used back-calculation of the growth of roach (Rutilus rutilus) caught in Lake Tåkern, Sweden, to find differences in growth during 2018’s hot summer versus the period 2012-2017. I compared growth during these years with results from a similar study from Lake Tåkern in 1978. For this comparison I used 1977 as a representative year for the 1970’s. I applied sclerochronology to the scales to determine age and growth. The results show that growth in terms of length increment was faster in 2018 than in 2012 – 2016. The results indicate that 2018 had an effect on the whole roach population, since significant differences were found across age groups. Additional comparisons between 1977 and 2018 showed no significant difference. Differences in roach growth rate between 2012-2018 could be caused by the differences in mean temperature during the roaches growing season, since 2018 was abnormally warm, and the difference between 1997 and 2018 could be attributed to 1977’s fish death. This means that if the pattern of climate change continues, roach growth rates will increase in the future regardless of age group.

Master of Science
Department of Family Studies Human Services
Rick J. Scheidt
Currently in the United States there are 2.7 million grandparent caregivers caring for 5.4 million grandchildren, with 883,386 of these grandparents caring for their grandchildren without any assistance from the child’s biological parent. These grandparents have unique needs and require support services that understand and recognize those needs. However, many of the resources currently available are not designed to assist this population. This report explores many of the issues grandparents face when taking over as the primary caregiver for their grandchild. Specifically this report highlights the financial, legal, and medical issues, as well as the need for respite care and housing. These particular issues were selected because they are commonly cited as difficult areas to navigate for grandparent caregivers, and also because there are crucial resources in each of these areas that allow grandparents to successfully raise their grandchild. Without these tools, the process of raising the grandchild can prove extremely difficult for grandparents, which can have negative consequences on the grandchildren. In addition it offers suggestions for grandparents seeking assistance regarding these issues, also providing several resources. This report also offers guidance for grandparent caregiver advocates and encourages future research and scholarship to explore programs assisting this population.

Age-related variation in demographic rates has significant consequences for population and evolutionary dynamics, and understanding the processes driving such variation is therefore an important aspect of evolutionary ecology. Reproductive performance may vary over the lifetime of an individual, and this may be the result of both variations in reproductive effort and changes in individual competency. For example, increasing experience is likely to have beneficial effects on reproduction during early life, and senescence, or declines in physiological function, may have negative impacts on the performance of older individuals. The rate at which these changes occur can vary dramatically between species, and even between individuals of the same species. However, understanding the causes and consequences of this variation in the rate of ageing is not always straightforward. As well as the individual-level processes described, the phenotypic composition of successive age classes will contribute to age-related variation observed at the population level. Abrupt changes in performance, such as the poor performance of first time breeders, may be obscured if individuals vary in their age at first reproduction. Population-level patterns may also be influenced by selection; for example, the selective disappearance of low quality individuals from older age classes may mask senescent declines in the performance of longer-lived individuals. Moreover, the physiological mechanisms that underpin within-individual changes in performance are not well understood. Unravelling the drivers of such age-related variation requires longitudinal data, following individuals throughout their lives, which presents challenges for the study of natural populations. Albatrosses are among the longest lived vertebrates. In this thesis, I use data from three species of albatross breeding at Bird Island, South Georgia (54°00’S, 38°03’W) to explore age-related variation. Focusing primarily on the wandering albatross, Diomedea exulans, I characterise the relationship between age and various reproductive traits, and decompose the population-level patterns to reveal effects of experience, senescence and terminal effects across the reproductive lifespan of individuals. I then consider foraging behaviour as a proximate driver of changes in reproductive performance in this species. Using tracking data collected over a 20 year period, I find limited evidence for age-related variation in foraging trips taken throughout the breeding cycle. Going one step further, I explore telomere dynamics in the wandering albatross, examining the potential for telomere length to act as a physiological marker of individual state. Finally, I move on to a species comparison, incorporating data from the black-browed (Thalassarche melanophris) and grey-headed albatross (Thalassarche chrysostoma). I compare the population- and individual-level ageing patterns of these three closely related species, and consider these in light of their differing life history strategies.

Within the policy context of ageing-in-place aspirations, this thesis examines the potential nature of housing for Australia's ageing population. By conceptualising housing and support together as an ecology and using grounded theory methodology to involve relevant stakeholders the thesis reveals both the desire and need for new urban and suburban based housing typologies arranged around collective living and mutual support. It further proposes a performance brief comprising desirable housing design principles. The thesis makes a contribution theoretically to the fields of architecture and critical gerontology.

The purpose of this study is to explore the concept of ‘Healthy Ageing’ in Hong Kong. The research attempts to explore the historical base from which ‘Healthy Ageing’ has been conceptualized in both Western and Chinese societies. This study also tries to provide an overview of literature that relevant to the ‘Healthy Ageing’ concept, and to provide an initial theoretical framework of ‘Healthy Ageing’ in a Hong Kong Chinese context. This study mainly adopts a qualitative approach in exploring the meaning of the concept. Since that ‘Healthy Ageing’ is likely to be conceptualized from the concept of health and ageing, which have been here since the early days, a method of documentary analysis on the origin of the concept and the paths leading to what it is at present has been employed. To re-construct the concept in Hong Kong, this thesis works towards an explanation of the historical base of the concept of ‘Healthy Ageing’ in both Chinese and Western societies since Hong Kong has evolved from a mixture of both cultures. Comparative cultural analysis and research’s own interpretation act as important roles in the present study to consolidate those raw documents in particular of the Chinese literature and construct a new model for the concept. Having constructed a model of ‘Healthy Ageing’, an expert in cultural studies was then interviewed at the end of May 2002 for verifying the model. Adopting a comparative cultural analysis, this study found that the fundamental elements, say physical and psychosocial well-being, in conceptualization of health in both East and West are almost the same, but manifestations and interpretations show some variations. Chinese people are apt to manifest and interpret their concept of health by an holistic approach, while the concept of health in Western societies is more likely to be manifested in a “compartmental” approach. These variations are basically derived from the differences of geo-cultural adaptations and the differences in individual lifestyles. As to the concept of ageing, this study revealed that ageing subject as a process instead of an end-stage of life-span. According to one view of human beings, life-spans can be divided into eight periods: Prenatal (pregnancy), Infancy (0-3), Early Childhood (3-6), Middle Childhood (6-12), Adolescence (12-20), Young Adulthood (20-40), Midlife (40-65) and Old Age (65+). It is a natural and integral process of growing old starting from birth and ending at death, in which a continuous process of biological, psychological and social changes will be experienced in a person’s life-course. After reconstructing health and ageing concepts, a tentative model of healthy ageing was developed in this study. In this study, healthy ageing is an holistic and dynamic concept. It is a state of interactions and adaptations between people and the environment in attaining optimal health in one’s life-span. It is a three-dimensional concept that encompasses health, health-ageing and health-ageing-environment dimensions. For the health dimension, there are six interrelated cross-life domains in achieving healthy ageing, which involve physical, psychological, social, economic, spiritual and environmental well-being. For the health-ageing dimension, people can achieve healthy ageing by attaining health in each stage of life. In this process, the health at younger stage influences the health at older stage. Thus, keeping healthy in early stage benefits the health conditions in later stages, although it cannot be said that what happens in early stage might not be unchangeable for later stages. Adopting health-promoting strategies in later stage can also provide opportunities for individuals to achieve healthy ageing. The health-ageing-environment dimension refers to the people-environment adaptation for attaining optimal health in their life-spans. Basically, people can ideally achieve healthy ageing by adopting health-promoting strategy at every stage of life. However, those favourable and unfavourable external environments will limit and change the opportunities for a person to achieve healthy ageing. To achieve optimal health in their life-spans, people are required to adjust themselves, adapting to their environment and also helping to shape the environment. Therefore, an individual-community approach is crucial for attaining healthy ageing.

Early life histories of alewife (Alosa pseudoharengus) and blueback herring (A. aestivalis), collectively known as river herring, are poorly documented for Chesapeake Bay populations. Improved knowledge of these early life histories potentially will aid fisheries, habitat and resource management. Investigations were conducted following two lines. First, alewife and blueback herring larvae reared from eggs were used to investigate methods for species identification and to validate the otolith increment method for age determination. Blueback herring larvae hatched from naturally-spawned eggs were reared to age 24 d. Alewife and blueback herring larvae hatched from artificially-spawned eggs were reared to age 32 d and age 37 d. Alewife larvae exhibited paired melanophores laterally along the notochord starting at about 15 mm SL, contracted xanthophores dorsally on the head, and lacked xanthochrome at the caudal fin base. Blueback herring exhibited one or two melanophores dorsally on the notochord starting at about 11 mm SL, relatively large xanthophores dorsally on the head, and xanthochrome at the caudal fin base. Other pigment variation was found. Estimated deposition of otolith increments was 1.16 and 0.90 increment d&\sp{lcub}-1{rcub}& for blueback herring larvae and 0.90 increment d&\sp{lcub}-1{rcub}& for alewife larvae. Increment enumeration was affected by otolith microstructure appearance, but estimated deposition did not differ statistically from one increment d&\sp{lcub}-1{rcub}&. Second, larval river herring distributions, abundances, growth rates, and hatch dates in the Pamunkey River tidal freshwater reach were analyzed. Distributions and abundances of zooplankton prey for river herring larvae were also analyzed. High abundances in two tidal creeks suggested that larvae occur in these areas from about late April to about mid-May. Larval river herring growth, pooled across seasons, was faster in the tidal creeks, 0.46 mm d&\sp{lcub}-1{rcub}&, than the mainstem river, 0.34 mm d&\sp{lcub}-1{rcub}&. Faster growth in the tidal creeks may increase survival by reducing the larval stage duration. Older larvae, pooled across habitats, grew faster than younger larvae, 0.59 mm d&\sp{lcub}-1{rcub}& and 0.35 mm d&\sp{lcub}-1{rcub}&. Larvae with relatively earlier hatch dates were associated primarily with the mainstem river while larvae with relatively later hatch dates were associated primarily with the tidal creeks. Zooplankton abundances were higher in the tidal creeks than the mainstem river.

As most multicellular organisms age, they undergo senescence: a progressive physiological deterioration that leads to declines in survival, reproduction, and performance in late life. Although senescence was once thought to be a phenomenon peculiar to captive animals and humans, field data have demonstrated age-related performance declines in a variety of taxa. Nevertheless, the ecology and evolution of senescence is not fully understood. The bulk of our knowledge about senescence in wild populations comes from studies of long-lived vertebrates, while short-lived invertebrates are often studied in the lab. Male antler flies (Protopiophila litigata; Diptera: Piophilidae) are an emerging insect model for studying senescence in nature, as they have short lifespans and high site-fidelity, facilitating collection of longitudinal data, and they can be easily reared and manipulated in the lab. This species is an ideal model to connect our lab-invertebrate- and field-vertebrate-based insights into aging biology. The developmental environment can have an especially large impact on life-history plasticity, including plasticity in senescence. This is because a developing organism makes “decisions” affecting phenotypes such as body size, sexual investment, metabolic rate, etc., which in turn can influence longevity and senescence. In my dissertation, I investigate how the early life environment, including larval diet and parental effects, plastically alters longevity and senescence in antler flies, primarily in the field in Algonquin Provincial Park. First, I quantified the effect of experimentally manipulated larval nutrient concentration on both early-life (growth and development) and late-life traits (reproduction, survival, senescence). Rich larval diet decreased development time, and although fast developers grew large and had low initial mortality in the field (and high average lifespan), they aged rapidly and had low mating rate. Due to these contrasting effects, diet and development time did not predict lifetime mating success, suggesting trade-offs among fitness components and alternative strategies in low condition males. Only male antler flies can be tracked in the field, so nothing is known about aging in females. In my second study, I compared longevity and aging of female and male antler flies in the lab. Theory suggests that males may age faster and die sooner than females, but empirical data are highly variable. Furthermore, the sexes may respond differently to variation in nutrition, so I reared flies on different larval diets based on the design of my first chapter. The sexes did not differ in senescence or longevity in the lab, and diet had a negligible effect. Large-bodied flies of both sexes senesced slower, in contrast to previous field data, highlighting plastic differences in senescence between wild and captive populations. In my third study, I quantified parental age effects on male antler flies. Offspring quality often changes with parental age, due to accumulation of germline mutations and/or changes in nongenetic maternal or paternal effects. To investigate whether and how parental age influences performance in wild insects, I mated lab-reared young and old females and males to one another in all combinations, and tracked their male offspring’s performance in the wild. Old fathers had long-lived sons, while maternal age had no effect on offspring survival in the field. Parental age did not affect mating success. Thus, the one parental age effect I observed was in fact positive, not negative. In my final study, I looked at how natural differences in larval diet, rather than artificial lab diets, influenced survival, mating, and senescence in wild male antler flies. Antlers become depleted of resources from year to year, as multiple generations of larvae feed within them. I collected larvae that grew inside nine different shed moose antlers, and tracked them in the field as adults. Males from high quality antlers (those that were more attractive to adult flies) completed metamorphosis more quickly, but did not differ in body size, longevity or lifetime mating success. However, large flies tended to live longer and have higher mating success. In conclusion, my dissertation research expands our understanding of plasticity in life history and senescence, particularly in insects, which are enormously abundant but understudied in this area. I quantified, for the first time to my knowledge, the effects of juvenile diet and parental age on longevity, mating success, and senescence in a wild insect.

In order to improve our knowledge of the mechanisms of ageing in animals, the main objective of the thesis was to understand the modulation of such mechanisms by the individual social role, within different social organisations. This objective thus addresses two main questions: i) describing the covariation of the degree of social complexity with ageing patterns; ii) highlighting the underlying cellular and molecular processes. Thanks to complementary and diversified studies (behavioural observations, dosage of the oxidative balance, qPCR measurement of telomere length, proteomics, metabolomics), the present thesis showed that sociality plays a role on ageing at many levels. In the zebra finch, social stress caused by aggression of the conspecifics induces oxidative stress and reduces telomere length in adults. In the sociable weaver, the social environment is of crucial importance during pre- and post-hatch development on the medium term survival of the chicks. Finally, in ants, we were able to show a positive relationship between the degree of sociality and maximum potential life span: this link was caste specific, being only significant for the most social queens. This is inline with a recent review by Lucas and Keller (2020) which concluded that the benefits of sociality are most sensitive for high levels of sociality and particularly in reproductive individuals. With regard to the molecular mechanisms of ageing,we were able to establish a causal chain between social stress, oxidative response and telomere erosion in zebra finches.The role of telomeres as a predictor of offspring survival has been confirmed (over at least 5 years) in the sociable weaver,a cooperative breeder bird. However, this link was not true in queen ants where the longest lived were those with the shortest telomeres. The co-evolution of anti-cancer mechanisms and longevity seems to be conserved since similar strategies are found in taxa as diverse as ants and rodents. On the other hand, and contrary to previous studies conducted on ants, we found that oxidative stress might be a marker of individual ageing. We suggest that the proxies of oxidative stress used so far in ants have been misleading or at least incomplete. Thus, understanding the physiological ageing particularities of ants and other social insects might require finding new relevant and specific markers. Finally, the sirtuins and mTOR signalling pathways, key precursors of which we have detected in ants, are molecular crossroads capable of activating or inhibiting cellular metabolism depending on the cell energy state. According to the studies carried out to date, these signalling pathways are among the first to be able to slow down the effects of ageing and extend life expectancy.However, specific studies need to be carried out to understand their fine regulation and thus assess the universality of these mechanisms in animal ageing. Based on our findings, we propose three points to be further addressed to better understand the mechanisms of ageing in social insects: i) the setup of experiments testing the effectiveness of energy trade-offs involving immunity or digestion metabolism; ii) measuring the telomerase activity among castes of various species in order to explore the telomere and telomere independent roles played by this enzyme in ageing; iii) the need to think about individual longitudinal follow-up and to study wild populations, after the first necessary stages in laboratory.
Doctorat en Sciences
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L’augmentation de la population âgée en perte d’autonomie laisse prédire en France un accroissement de la demande d’accueil en EHPAD (Établissements d’Hébergement pour Personnes Âgées Dépendantes), pourtant déjà au cœur d’une crise socio-professionnelle, financière, morale et politique. Dans ce contexte, le développement de robots sociaux semble porter des promesses d’amélioration de la qualité de vie des personnes âgées et d’allégement de la charge de travail du personnel. Cependant en pratique, ces robots sont peu adoptés à cause de limites techniques, éthiques, culturelles et socio-économiques. Leur conception est accusée d’être techno-centrée, hors-sol, influencée par la science-fiction ou pas assez participative et à l’origine de produits inadaptés aux besoins, enjeux, valeurs et à la complexité des environnements sociaux humains. Postulant que l’innovation technologique doit être guidée par l’innovation sociale, cette thèse en design interroge la pertinence des robots sociaux pour résoudre les enjeux liés à la crise des EHPAD. Elle aborde leur arrivée comme un vecteur de transformations sociales et adopte un point de vue systémique pour appréhender leur place comme nouveau composant d’un tissu relationnel composé d’humains et d’artefacts. Par la mise en place de deux projets, cette recherche-projet en design questionne les modes d’adaptation des robots sociaux, leurs impacts sur l’écologie du vieillissement en EHPAD et les attentes des usagers. Le premier projet comprend l’observation d’un EHPAD sans robots, l’ethnographie de l’usage de six robots dans sept établissements et cinq ateliers de codesign. Le deuxième projet consiste en la conception participative d’une fiction de design explorant des scénarios prospectifs. Cette recherche propose ainsi une lecture du présent et de possibles futurs socio-technologiques et présente des contributions empiriques, méthodologiques et théoriques. En analysant avec un prisme écologique l’inadaptation des robots sociaux actuels en EHPAD, cette thèse propose une transformation des approches d’innovation et de conception pour ces environnements. Elle recommande notamment une compréhension située de la réalité du soin au grand âge avant tout développement technologique et préconise la création de nouveaux formats de projet ouvrant davantage d’espace de collaboration. Elle remet en perspective la complémentarité humains-robots en dehors des imaginaires dominants et suggère de s’affranchir des logiques solutionnistes au profit de changements sociaux systémiques. Du point de vue méthodologique, ce travail explore l’intégration d’une triple approche en design : écologique, participative et spéculative. Cette méthodologie symbiotique repositionne les usagers dans la détermination de leurs futurs et questionne les implications de l’usage de robots en EHPAD pour redéfinir le préférable. Enfin, cette recherche produit une réflexion théorique sur la place symptomatique du robot social dans la transformation socio-politique du soin et propose de mobiliser cet objet non plus comme une solution, mais comme un outil de recherche dans la réflexion sur les futurs préférables de la vie en institution
In France, the growing population of older adults losing their autonomy points to an increase in the demand for institutional care in the midst of a socio-professional, financial, moral and political crisis. The development of social robots promises to improve quality of life for the elderly and reduce the workload of staff in care facilities. However, in practice, these robots are not widely adopted because of technical, ethical, cultural, and socio-economic limitations. Their design has been called techno-centric, out of touch, influenced by science fiction or not participatory enough, resulting in products not suited to the needs, issues, values, and complexity of human social environments. Rooted in the design sciences and holding that social innovation must guide technological innovation, this thesis examines the relevance of social robots in tackling the nursing homes crisis. It approaches their rise not as a technical challenge, but as a vector of social transformation, and adopts a systemic lens to understand their place as a new component of a relational network of humans and artefacts. Through the implementation of two field projects, this project-grounded research (PGR) study in design examines the ways in which social robots adapt to the ecology of aging in nursing homes, their systemic impact, and the expectations of facility users. The first project includes a qualitative observation of a care facility without robots, a design ethnography of the use of six robots in seven facilities, and five co-design workshops. The second project builds a participatory design fiction exploring prospective scenarios. This work offers a reading of the current reality as well as potential socio-technological futures of life in care homes, and presents empirical, methodological and theoretical contributions. By analysing the unsuitability of current social robots in nursing homes from an ecological perspective, this thesis proposes a transformation of innovation and design approaches for these environments. In particular, it advocates a situated understanding of the reality of care prior to any technological development. It suggests the creation of new project formats opening more space for collaboration. It puts human-robot complementarity back into perspective separate from dominant imaginaries and advocates breaking away from solutionist thinking in favour of systemic social change. From a methodological point of view, this work explores the integration of a triple approach to design: ecological, participatory and speculative. This symbiotic methodology helps to rethink the role of users in determining their future and to question the implications of using robots in nursing homes to redefine preferable outcomes. Finally, this research produces a theoretical reflection on the symptomatic place of social robots in the socio-political transformation of care and proposes to mobilise them no longer as a solution but rather as a research tool in establishing what constitutes preferable futures for life within facilities

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The methodology of the accelerated aging test controlled deterioration to achieve the physiological quality of Lafoensia glyptocarpa Koehne seeds, separated into light and dark seeds, and to correlate if these seeds have their color due to different stages of maturation or whether the color is original phenotypic. The initial quality of the seeds was obtained through the tests of moisture content, conductivity and seedling emergence in greenhouse. The accelerated aging test was conducted at 40ºC during 24, 48, and 72 hours, using the traditional, NaCl saturated solution and controlled deterioration. The research was conducted in a completely randomized design. The saturated salt accelerated aging test and controlled deterioration was efficient for vigor evaluation of Lafoensia glyptocarpa Koehne seeds, and the period of 48hours at 40ºC was considered as the most adequate procedure to evaluate seed vigor levels, leading to the belief that colored seeds come from different stages of maturation.
O presente trabalho teve por objetivo avaliar as diferentes formas de se efetuar o teste de envelhecimento acelerado e deterioração controlada para avaliação do potencial fisiológico de sementes de Lafoensia glyptocarpa Koehne, separadas em sementes claras e sementes escuras, e correlacionar se estas sementes têm sua coloração devido a diferentes estádios de maturação ou se a coloração é de origem fenotípicas. A avaliação inicial dessas sementes consistiu na determinação do grau de umidade, condutividade e emergência de plântulas em casa de vegetação. O envelhecimento artificial foi implementado a 40ºC durante 24, 48, e 72 h, com e sem uso de solução saturada de NaCl, e para o teste de deterioração controlada as sementes foram umedecidas até 20% de umidade e posterior envelhecimento em câmara úmida a 40°C durante 24, 48 e 72h. O experimento foi conduzido em delineamento inteiramente casualizado. Dentre os procedimentos adotados no teste de envelhecimento artificial e o período de exposição de 48 horas a 40ºC com uso de solução saturada de NaCl, e deterioração controlada revelou-se adequado para a avaliação do potencial fisiológico de sementes de Lafoensia glyptocarpa Koehne, levando a crer que a coloração das sementes provem de estádios de maturação diferentes.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O uso de ferramentas matemáticas, estatísticas e computacionais para estudar o comportamento de sistemas biológicos se faz cada vez mais presente. Este interesse é devido à complexidade apresentada pelas populações, que sofrem influências externas, relativas à interação com o ambiente e influências internas, conseqüências dos interesses conflitantes entre os indivíduos do ecossistema. A nossa proposta é de modelar computacionalmente alguns fenômenos biológicos observados em populações reais, para tentar entender melhor o que está acontecendo e analisar os prováveis efeitos de fatores externos, como os avanços na área de saúde, mudanças no clima ou invasão de nichos por outras espécies. Mostraremos neste trabalho modelos distintos, destacando entre as ferramentas computacionais aplicadas os algoritmos genéticos, que combinam a sobrevivência dos organismos mais adaptados com pequenas mudanças aleatórias nas suas estruturas, e os autômatos celulares, que permitem o estudo da distribuição espacial da população e utilizam regras simples de evolução. Apresentaremos também, uma solução analítica aproximada para um dos problemas estudados. Nos dois primeiros capítulos utilizaremos o modelo Penna para a dinâmica de populações que apresentam estrutura etária, portanto ideal para estudar o envelhecimento de populações, adaptando o modelo à situação a ser estudada. Nos capítulos seguintes iremos propor dois novos modelos para a colonização de substrato por animais marinhos sésseis, onde larvas trazidas de populações distantes competem pela colonização de superfícies submersas, onde se manterão fixos durante toda a vida.
The usefulness of mathematical, statistical and computational tools to study the behavior of biological systems has been affirmed on many opportunities. This interest is mostly due to the complexity presented by the populations that can suffer external influences,for example, due to the interaction with the environment, and internal influences due to the conflicting interests of the individuals of the ecosystem. Our proposal is modelling in a computer, biological phenomena observed in real populations, in order to understand and to analyze the effects of external factors, such as changes on health care and Medicine, changes in the climate or invasion of niches from intruder species. We will work with different models and computational tools such as genetic algorithms, that combine the survival of the fitter organisms with small random changes in its structures; and cellular automata, that allow the study of the space distribution of the population from simple rules for the dynamical evolution. In addition, we also present an analytic solution for one of the studied situations. In the first two chapters we use the so-called Penna model, appropriate to study the aging of populations, for being age structured, by modifying the model according to the situation we will be studying. In the following chapters we propose two new models for the substratum colonization for sessile marine animals, where larvae brought from distant populations compete for the colonization of submerged surfaces, where they will keep fixed during their lifetime.