Dissertations / Theses on the topic 'POPULATION THEORY'

Le modèle des populations protocols a été proposé pour capturer les spécificités de réseaux opportunistes constitués d'une population d'agents mobiles à la mémoire limitée capables de communications sans fil par paires. L'objet de cette thèse est d'étendre la compréhension et l'analyse des population protocols ainsi que leurs liens avec d'autres modèles de dynamiques de populations. La première contribution de cette thèse est l'étude de la traduction en terme de protocoles de population de la dynamique d'une population d'agents jouant à un jeu de manière répétée les uns contre les autres et adaptant leur stratégie selon le comportement de PAVLOV. Nous montrons que les protocoles issus de tels jeux sont aussi puissants que les protocoles de population généraux. La deuxième contribution consiste à étudier des hypothèse de symétrie dans les jeux et dans les transitions d'un protocole de population, pour montrer que, si les protocoles de population symétriques sont équivalents aux protocoles généraux, les jeux symétriques sont, eux, significativement moins puissants. La troisième contribution est de montrer comment étudier le comportement d'une protocole de population lorsque la taille de la population tend vers l'infini en approchant la dynamique résultante à l'aide d'une équation différentielle ordinaire et de définir un calcul par grande population comme la convergence de cette équation différentielle vers un équilibre stable. La quatrième et dernière contribution de la thèse est la caractérisation des nombres calculables en ce sens comme étant très exactement les réels algébriques des [0,1]
Population protocols were introduced to capture the specifies of opportunistic networks of tny mobile agents with limited memory and capable of wireless communication in pairs. This thesis aims at extending the understanding and analysis of population protocols as well as their links to other models of population dynamics including ones from game theory. The first contribution of this thesis is to translate in terms of population protocols the dynamics of a population of agents playing a game repeatedly against each-other and adapting their strategy according to the PAVLOV behaviour. We show that protocols born from games are exactly as powerful as general population protocols. The second contribution consists in the study of the impact of symmetry on games and in the transitions of a population protocol to show that, if symmetric population protocols are equivalent to general protocols, symmetric games are significantly less powerful. The third contribution is to show how the dynamic of a population protocol can be approximated by an ordinary differential equation when the population grows to infinity. We then define a computation by a large population to be the convergence of this differential equation to a stable equilibrium. The fourth and final contribution of this thesis is the characterisation of the numbers computable in the above sense as exactly the algebraic real numbers in [0,1]

'If sanity and insanity exist, how shall we know them?' (Rosenhan, 1973, p.250). This question, posed almost 40 years ago, continues to pervade mental health debates and polarise opinion. The current research explores how unusual beliefs are negotiated and constructed by individuals in a non-clinical population. I considered this from the perspective of individuals who endorse conspiracy theories ('belief holders') as well as a friend, family member or partner. Previous research indicates that 'insanity' is often identified and constructed by systems around a person rather than by the person themselves. By taking this approach, I aimed to elucidate the intra- and inter-personal negotiation of claims from two different perspectives. Each belief holder and a self-selected friend, family member or partner were interviewed together to examine the intra- and inter-personal negotiation of claims, how claims were constructed by those around the belief holder and how emotions associated with claims were managed. Grounded theory was used to analyse the data. Two core-categories were developed from the data; 'discovering and managing a new world' and 'experiencing and negotiating claims with others'. The first core-category focused on the intra-individual experience of claims, exploring how these were discovered, experienced and integrated into participants' sense of themselves and their identities. The second core-category explored the inter-personal negotiation of claims, how claims were constructed by those closest to belief holders and the strategies developed by participants to negotiate claims in diverse social contexts. Both core-categories were complementary, with many processes running in parallel between the two. A model of how participants experienced and negotiated claims was developed, combining the two core-categories and explicating the relationships between the two. The clinical and research implications of the findings are explored.

A set of distributional assumptions regarding the demographic processes of birth, death, emigration and immigration have been assembled to form a probabilistic model framework of population dynamics. This framework was summarized as a Bayesian network and Bayesian inference techniques are exploited to infer the posterior distributions of the model parameters from observed data. The birth, death and emigration processes are modelled using a hierarchical beta-binomial model from which the inference of the posterior parameter distribution was analytically tractable. The immigration process was modelled with a Poisson type regression model where posterior distribution of the parameters has to be estimated numerically. This thesis suggests an implementation of the Metropolis-Hasting algorithm for this task. Classifi cation of incomings into subpopulations of age and gender is subsequently made using a Dirichlet-multinomial hierarchic model, for which parameter inference is analytically tractable. This model framework is used to generate forecasts of demographic data, which can be validated using the observed outcomes. A key component of the Bayesian model framework used is that is estimates the full posterior distributions of demographic data, which can take into account the full amount of uncertainty when forecasting population growths.
Genom att använda en mängd av distributionella antaganden om de demografiska processerna födsel, dödsfall, utflyttning och inflyttning har vi byggt ett stokastiskt ramverk för att modellera befolkningsförändringar. Ramverket kan sammanfattas som ett Bayesianskt nätverk och för detta nätverk introduceras tekniker för att skatta parametrar i denna uppsats. Födsel, dödsfall och utflyttning modelleras av en hierarkisk beta-binomialmodell där parametrarnas posteriorifördelning kan skattas analytiskt från data. För inflyttning används en regressionsmodell av Poissontyp där parametervärdenas posteriorifördelning måste skattas numeriskt. Vi föreslår en implementation av Metropolis-Hastingsalgoritmen för detta. Klassificering av subpopulationer hos de inflyttande sker via en hierarkisk Dirichlet-multinomialmodell där parameterskattning sker analytiskt. Ramverket användes för att göra prognoser för tidigare demografisk data, vilka validerades med de faktiska utfallen. En av modellens huvudsakliga styrkor är att kunna skatta en prediktiv fördelning för demografisk data, vilket ger en mer nyanserad pronos än en enkel maximum-likelihood-skattning.

In this thesis, we study collective phenomena that arise from microscopic fluctuations at the individual level of two different living populations. First, we study evolutionary dynamics of two-species competitions in a well-mixed environment subject to population size fluctuations. We demonstrate a mechanism for neutral evolution such that population size fluctuations favor a fixation of one species over the other. An effective evolutionary dynamics for fluctuation-induced selection is derived. We then investigate strong mutualism, in a limit where a varying population size can strongly influence the evolutionary dynamics. We determine fixation probabilities as well as mean fixation times taking into account the population size degree of freedom. The results elucidate the interplay between population size fluctuations and evolutionary dynamics in well-mixed systems. Second, we investigate  single species marine population  subject to a constant flow field and quenched random spatially fluctuating growth rates.  We show that the non-equilibrium steady-state population density of a generalized Fisher-Kolmogorov-Petrovsky-Piscounov (FKPP) equation develops a flow-driven striation pattern.  The striations are highly asymmetric with a longitudinal correlation length that diverges linearly with the flow speed and a transverse correlation length that approaches a finite velocity-independent value. The findings suggest that, although the growth disorder can be spatially uncorrelated, correlated population structures with striations emerge naturally at sufficiently strong advection.
Physics

For the last thirty years or so, there has been a search underway for a theory that canaccommodate our intuitions in regard to moral duties to future generations. The object ofthis search has proved surprisingly elusive. The classical moral theories in the literature allhave perplexing implications in this area. Classical Utilitarianism, for instance, implies thatit could be better to expand a population even if everyone in the resulting populationwould be much worse off than in the original. The main problem has been to find an adequate population theory, that is, a theoryabout the moral value of states of affairs where the number of people, the quality of theirlives, and their identities may vary. Since, arguably, any reasonable moral theory has totake these aspects of possible states of affairs into account when determining the normativestatus of actions, the study of population theory is of general import for moral theory. A number of theories have been proposed in the literature that purport to avoidcounter-intuitive implications such as the one mentioned above. The suggestions arediverse: introducing novel ways of aggregating welfare into a measure of value, revising thenotion of a, life worth living, questioning the way we can compare and measure welfare,counting people's welfare differently depending on the temporal location or the modalfeatures of their lives, and challenging the logic of axiological and normative concepts. Weinvestigate the concepts and assumptions involved in these theories as well as theirimplications for population theory. In our discussion, we propose a number of intuitively appealing and logically weakadequacy conditions for an acceptable population theory. Finally, we consider whether it ispossible to find a theory that satisfies all of these conditions. We prove that no such theory exists.

Thesis advisor: Mary E. Walsh
School readiness at kindergarten is an important predictor of children's future academic success (Duncan et al., 2007). While early pre-academic and behavioral skills are important for all students, there is considerable inequality in students' levels of readiness at the start of school (Coley, 2002; Lee & Burkam, 2002; Razza, Martin & Brooks-Gunn, 2010; Ryan, Fauth, & Brooks-Gunn, 2006; Welsh, Nix, Blair, Bierman & Nelson, 2010), and research has pointed to a range of out-of-school and poverty-related factors that contribute to these inequalities (Coley, 2002; Dearing, 2008; Foster, 2002; Hill, 2001; Razza et al., 2010; Ryan et al., 2006). This study utilizes relational developmental systems theory (Lerner, 2006; 2011) to examine the individual and contextual factors that co-act dynamically to shape and predict student outcomes. Specifically, this study extends the body of research on early child development by examining the factors that predict school readiness skills within a sample of 521 young children preparing to enter the first grade from urban early education programs. Multilevel regression models indicate that student characteristics, classroom characteristics, and peer contexts each predict students' school readiness scores, and that the interactions among these variables make unique contributions to the prediction of school readiness scores as well. Implications for theory, policy, and practice are discussed along with recommendations for future research
Thesis (PhD) — Boston College, 2015
Submitted to: Boston College. Lynch School of Education
Discipline: Counseling, Developmental and Educational Psychology

A new strategy to fight mosquito-borne disease is based on infections of the maternally-transmitted, intracellular bacterium Wolbachia pipientis. Estimates predict that Wolbachia infects nearly half of all insect species, as well as other arthropods and some nematodes. Wolbachia manipulates the reproduction of its host to promote infection, most commonly causing a form of conditional sterility known as cytoplasmic incompatibility. Generally, Wolbachia infections are benign and do not inflict significant costs upon its host. However, studies demonstrate that some infections are associated with substantial costs to its host. These same infections can also induce pathogen interference and decrease vector competency of important disease vectors. Theory predicts that organisms that incur costs relative to conspecifics are less competitive and their competitive exclusion is expected. In the case of Wolbachia, the bacterium can influence reproduction such that phenotypes with lower fitness may still reach fixation in natural populations. In this dissertation, I describe theoretical and empirical experiments that aim to understand the invasion and stability of Wolbachia infections that impose costs on their host. Particular attention is paid to immature insect lifestages, which have been previously marginalized. These results are discussed in relation to ongoing vector control strategies that would use Wolbachia to manipulate vector populations. Specifically, I discuss the cost of novel Wolbachia infections in Aedespolynesiensis, which decreases larval survival and overall fitness relative to wild-type mosquitoes. Then, a theoretical framework was developed to determine the significance of reductions in larval viability in relation to the population replacement disease control strategy. Further theoretical studies determined that Wolbachia infections, once established, resist re-invasion by uninfected individuals despite relatively high costs associated with infection so long as the infection produces reproductive manipulations. Additional studies determined that larvae hatched from old eggs experience reduced survival in mosquito strains with novel Wolbachia infections when compared to the wild-type. To validate the theoretical studies, model predictions were tested empirically to determine the importance of the larval viability. Finally, a COPAS PLUS machine was evaluated and its role in understanding early larval development in mosquitoes is discussed. The importance of integrated research in disease control is highlighted.

Cette thèse se propose d’étudier sous l’angle de la théorie algorithmique des jeux divers jeux inspirés de situations réelles rencontrées dans les domaines des réseaux informatiques et de la biologie. Ces jeux se caractérisent par un grand nombre de joueurs disposant chacun d’une information incomplète à propos des autres joueurs. Dans la théorie classique, ces jeux rentrent dans la catégorie des jeux extensifs à information imparfaite et sont modélisés à l'aide d'arbres. Ils restent toutefois très difficiles à analyser en détail, à cause de leur inhérente complexité, liée notamment à une profondeur d’arbre potentiellement infinie. Nous avons relevé le défi de cette tâche en diversifiant les méthodes de résolution et en mettant l’accent sur son aspect interdisciplinaire.Cette thèse, outre l’introduction et la conclusion, se divise en trois parties. Dans la première, nous adoptons le point de vue de la théorie des jeux classique. Nous proposons un modèle de jeu qui correspond à une large classe de problèmes rencontrés dans la théorie du calcul distribué. Les principales contributions de cette partie sont, d’une part, de montrer comment passer d’un point de vue purement algorithmique du problème à un point de vue correspondant à la théorie des jeux, et, d’autre part, de prouver l’existence d’équilibres satisfaisants pour la classe de jeux obtenue. Ce deuxième point est essentiel et garantit que la théorie des jeux est adaptée à l’étude de tels jeux distribués, malgré leur complexité.La seconde partie est consacrée à l’étude d’un jeu omniprésent au sein des systèmes biologiques que l’on nomme jeu de la dispersion. Il modélise la situation dans laquelle un groupe d’animaux doit se partager une certaine quantité de ressources répartie entre différents sites géographiques. La difficulté du jeu provient du fait que certains sites contiennent plus de ressources que d’autres, mais risquent également d’attirer plus de joueurs. Le partage est alors difficile. Nous proposons une règle de répartition des ressources qui permet de maximiser les ressources exploitées par l’ensemble du groupe. Cette partie est aussi l’occasion de revisiter les liens étroits entre le concept de distribution libre idéale, très présente dans la théorie du fourrageage, et le concept de stratégie évolutionnairement stable, concept clé de la théorie des jeux évolutionnaires.La troisième partie se concentre sur l’étude du comportement d’une certaine espèce de petites chauve-souris vivant au Mexique, dans le désert de Sonora, et se nourrissant la nuit du nectar des cactus géant de l’espèce protégée Saguaro. Après la présentation des résultats expérimentaux obtenus sur le terrain, nous proposons une simulation informatique de leur comportement. Les résultats de ces simulations permettent de formuler des hypothèses intéressantes à propos du fonctionnement cérébral de ces petits mammifères. Nous étudions ensuite un modèle théorique de jeu inspiré de cette situation réelle. L’étude de ce modèle abstrait nous permet de distinguer les caractéristiques fondamentales du jeu, et de renforcer notre approche de théorisation du comportement de fourrageage. Cette étude ouvre également la voie à l’application de ce type de modèle à d’autres situations, impliquant un comportement animal ou humain
The aim of this thesis is to use algorithmic game theory tools to study various games inspired from real world problems in the fields of information networks and biology. These games are characterized by a large number of players, each with incomplete information about other players. In classical game theory, these games fall into the category of extensive games with imperfect information, which are modeled using trees. However, these games remain very difficult to analyze in details, because of their intrinsic complexity, which is linked with their possibly infinite tree depth. Nevertheless, we have taken up the challenge of this task, while diversifying the methods of resolution, and emphasizing its interdisciplinary aspect.Besides the introduction and the conclusion, the thesis is divided into three parts. In the first part, we adopt the point of view of classical game theory. We propose a game that corresponds to a wide class of problems encountered in the theory of distributed computing. The main contributions of this part are, on the one hand, to show how to transform a purely algorithmic problem into a game, and, on the other hand, to prove the existence of satisfactory equilibria for the resulting class of games. This second point is essential, as it guarantees that game theory is adapted to the study of distributed games, despite their complexity. The second part is dedicated to the study of a game omnipresent within biological systems, that we call dispersion game. This game models the situation in which a group of animals must share a certain amount of resources scattered among different geographical sites. The difficulty of the game comes from the fact that some sites contain more resources than others, but may also attract more players. We propose a rule for the distribution of resources which makes it possible to maximize the resources exploited by the whole group. This part of the thesis is also an opportunity to revisit the close links between the concept of ideal free distribution, very present in the theory of foraging, and the concept of evolutionarily stable strategy, a key concept of evolutionary game theory. The third part focuses on the study of the behavior of a specific species of small bats living in Mexico, in the Sonoran Desert, and feeding at night from the nectar of the giant Saguaro cacti, a protected species. After the presentation of the experimental results obtained in the field, we propose a computer simulation of their behavior. The results of these simulations make it possible to formulate interesting hypotheses about the cerebral activities of these small mammals. We then study a theoretical model of game inspired by this real situation. The study of this abstract model allows us to distinguish the fundamental characteristics of the game, and to reinforce our approach of theorizing foraging behavior. This study also opens the way to applying this type of model to other situations, involving animal or human behavior

This thesis presents population dynamics models that can be applied to predict the rate of spread of the Neolithic transition (change from hunter-gathering to farming economics) across the European continent, which took place about 9000 to 5000 years ago. The first models in this thesis provide predictions at a continental scale. We develop population dynamics models with explicit kernels and apply realistic data. We also derive a new time-delayed reaction-diffusion equation which yields speeds about a 10% slower than previous models. We also deal with a regional variability: the slowdown of the Neolithic front when reaching the North of Europe. We develop simple reaction-diffusion models that can predict the measured speeds in terms of the non-homogeneous distribution of pre-Neolithic (Mesolithic) population in Europe, which were present in higher densities at the North of the continent. Such models can explain the observed speeds.
Aquesta tesi presenta models de dinàmica de poblacions que es poden aplicar a la transició del neolític (canvi d’una societat de caçadors-recol•lectors a una societat agrícola) per tal de predir-ne la velocitat d’expansió al continent europeu, que va tenir lloc fa entre 9000 i 5000 anys. Els primers models d’aquesta tesi proporcionen prediccions a escala continental. Desenvolupem models de dinàmica poblacional incloent kernels explícits i dades realistes. També demostrem una nova equació de reacció-difusió amb retard temporal la qual prediu velocitats fins a un 10% més lentes que en demostracions anteriors. També tractem una variabilitat regional: la disminució del ritme d’expansió del front neolític al nord d’Europa. Desenvolupem models de reacció-difusió senzills que tenen en compte la distribució no homogènia de poblacions preneolítiques (mesolítiques) a Europa, les quals eren presents amb majors densitats al nord del continent. Aquests models poden predir les velocitats mesurades.

In this thesis we developed two approaches to study positive selection and genetic adaptation in the human genome. Both approaches are based on applications of network theory. In the first approach, we studied how the signals of selection are distributed among the genes of a metabolic pathway. We use a network representation of the Asparagine N-Glycosylation pathway, and determine if given positions are more likely to be involved in selection events. We determined a different distribution of signals between the upstream part of this pathway, which has a linear structure and is involved in a conserved process, and the downstream part of the pathway, which has a complex network structure and is involved in adaptation to the environment. In the second approach, we applied a network representation of the set of genotypes observed in a population (Genotype Network) to next-generation sequencing data. The main result is a genome-wide picture of how the populations of the 1000 Genomes dataset have explored the genotype space. We found that the genotype networks of coding regions tend to be more connected and more expanded in the space than non coding regions, and that simulated sweeps have similar patterns compared to simulated neutral regions.
En esta tesis hemos desarrollado dos métodos para estudiar los patrones de selección positiva y adaptación genética en el genoma humano. Ambos métodos se basan en aplicaciones de teoría de redes. En la primera aplicación hemos investigado cómo las señales de selección están distribuidas a lo largo de una ruta metabólica. Hemos utilizado una representación de la ruta de N-Glicosilación, para estudiar si determinadas posiciones tienen más probabilidades de estar implicadas en eventos de selección positiva. Hemos comparado la distribución de las señales de selección entre la primera parte de la ruta metabólica, que tiene una estructura muy lineal y está involucrada en un proceso conservado, y la segunda parte de la ruta, que tiene una estructura de redes compleja y está involucrada en adaptación al ambiente. En la segunda aplicación hemos aplicado el concepto de redes de genotipos (Genotype Networks) a datos de secuencia de nueva generación. El resultado es un análisis completo de cómo las poblaciones de 1000 Genomas han explorado el espacio de genotipo. Las redes de genotipos de regiones codificantes suelen estar más conectadas y más expandidas que las regiones no-codificantes. Además, por medio de simulaciones hemos observado los patrones esperados para eventos de selección positiva.

This study is an exploratory investigation into understanding adherence behaviour in a random sample of 13 asthmatic adolescents selected from a General Practice population. Personal Construct Theory is used as a theoretical and methodological framework within which to assess the meaning of having asthma and taking medication to each participant. Asthma and adherence perceptions are also obtained in a semistructured interview. Measures of subjective asthma status are obtained using a global severity rating scale and the Paediatric Asthma Quality of Life Questionnaire. Subjective measures of adherence are also obtained from the participant, their parent and their health-care provider. A qualitative analysis of the results reveals that, for the majority of the sample, self-construal of adherence is consistent with self-construal of asthma. A content analysis of elicited constructs reveals a category of themes, which show direct parallels with models of health behaviour change and adolescent development. It is proposed that these results provide the basis for the development of a model of adherence in asthmatic adolescents. The validity of the grid methodology is assessed through feedback of the results to the participants and comparison of data sources. It is concluded that the grid is a valid tool for addressing perceptions of asthma and adherence. Reliability of the methodology is not addressed. Implications for the use of the methodology within a clinical setting and recommendations for further research are discussed.

Formative periods represent early phases in life when we are particularly sensitive to experiences that influence later choices. This investigation hypothesised that the design of products associated with formative periods continues to influence preference throughout life. In design for an ageing population these preferences are important because designers often wrongly assume a decline in interest in design and physical ability. If these assumptions are prioritised there can be a detrimental effect on the visual sensitivity and emotional value products convey. In the United Kingdom a significant proportion of the ageing population is financially independent, physically healthy and resistant to traditionally negative associations of ageing. However, limited interrogation of the design process, or of the products produced, leaves a largely youth orientated design industry ill- equipped to challenge these associations and design for consumers whose experiences differ from their own. This investigation interviewed leading design professionals to test these assumptions and to inform an innovative questionnaire to identify visual preference. The questionnaire incorporated images of domestic products from 1930 to 1990 and asked for rapid responses reflecting intuitive preferences. A fifty five percent , response rate was achieved from 5,000 questionnaires posted to respondents aged fifty to seventy five years. Analysis of the findings identified two associations. Firstly, a statistically small association between age and visual preference, older respondents preferred older products, although the association was marginal and insufficient to support the hypothesis. Secondly, visual analysis revealed a strong preference for the most familiar form of the product, proposed as representing the 'contemporary essence'. These findings challenge assumptions that ageing is accompanied by a decline in design interest. Rather, the economic and social cost of establishing a design environment reduces the flexibility of future choices. These issues are age neutral. To address these issues, a critically reflective design approach is proposed as a positive response to an ageing population in an inclusive society.

One of the most important but least discussed issues of our era is the problem of population--its size, density, and diversity, its explosive growth globally, its stability or shrinkage regionally, and the challenges it creates as we attempt to redefine who we are and what our place is in relation to the rest of the natural world. Utilizing an interdisciplinary approach, I trace the meaning of population in ancient, pre-Malthusian, and post-Malthusian political economy, note its contemporary treatment in politics, economics and science, and examine the reasons for its decline and relative absence in present-day environmental philosophy. While some of the helpful ways in which commentators of the past approached the topic have been largely forgotten, such as valuing the relation between the size of a community and its ability to function harmoniously, I argue that historical debates do not address the issue in relation to current conditions. I apply ethical orientations from the Continental and Classical American philosophical traditions, namely those of John Dewey and Max Scheler to problems associated with the revival of the subject. Both men viewed persons as irreducibly unique and unquantifiable beings with open and infinite creative possibilities. Among other insights, Dewey and Scheler emphasized quality over quantity, and they stressed the questions of value associated with population issues and ways of adjusting both ourselves and our valuing to a quality-centered world. I conclude by pointing to ways in which inquiry into the meaning of population intersects with contemporary social and environmental challenges.

The majority of local areas in the UK are faced with an ageing population. Popular retirement destinations in coastal and more rural areas are particularly affected. The thesis aims to find out how local areas strategically tackle these demographic shifts. The British government has issued strategic guidance for local areas, but as yet little is known about how actual responses look. The literature has largely focused on good practice compilations. Consequently, the thesis attempts to analyse in depth local areas’ experiences in planning for an ageing population. The main research question is: How do local actors in the UK plan for population ageing? A grounded theory approach has been chosen to develop theoretical concepts from empirical data. Local governance and collective learning are used as sensitising concepts, i.e. wider theoretical perspectives. Due to the state of research and the aim to gather detailed knowledge regarding the planning for an ageing population in local areas, a qualitative research design has been chosen. More precisely, it is a multiple case study design, covering the three heterogeneous cases North Tyneside, Poole and Wealden. Empirical data has been assembled from qualitative interviews with local experts and documents such as local strategies or minutes of meetings. The results are threefold. Firstly, local governance arrangements are analysed. This covers the identification of involved actors, their action orientations and interactions. As approaches in planning for an ageing population differ across organisations, a typology of individual actors is developed. Moreover, it is observed that and analysed how traditional hierarchical steering by public bodies is complemented by more network-like forms of governance, for example multi-organisational older people’s partnerships. Secondly, local learning processes in planning for an ageing population are reconstructed. Four phases are differentiated: setting the agenda for the topic of ageing and older people followed by building up knowledge on the subject and collective learning in a narrower sense and, finally, strategy-making. Interrelations between governance arrangements and collective learning are analysed, particularly with respect to different forms of learning in different types of older people’s partnerships. Finally, central challenges and perspectives arising from the analysis of governance arrangements and learning processes are discussed. On the one hand, these pertain to the cross-cutting nature of ageing, on the other hand they are due to the ambivalent influence from national government on local areas. Ageing affects various spheres of local steering activity. Among the main implications for local areas in the UK are the continuous search for responsibility and the struggle to broaden the agenda beyond health and care. This has led to experimenting with governance structures, intensifying involvement of older people and developing inter-agency older people strategies and others as catalysts for further development. The strong influence from central government on local steering advances local reactions to ageing but provokes superficial and unsustainable answers at the same time. Overall, the thesis provides in-depth empirical knowledge on local planning for an ageing population. The theoretical lenses local governance and collective learning have been used to generalise from the practical experiences in the three case study areas. The thesis concludes with recommendations for practitioners locally and at the national level. These refer inter alia to local governance arrangements which come up to the issue’s cross-cuttingness and to national guidance and regulation which could facilitate their introduction or modification
Die Mehrzahl britischer Gemeinden ist mit einer alternden Bevölkerung konfrontiert. Küstengebiete und ländliche Räume sind besonders betroffen, da sie als Altersruhesitz bevorzugt werden. Ziel der Dissertation ist es, den strategischen Umgang der Gemeinden mit diesen demographischen Veränderungen zu beleuchten. Die britische Nationalregierung gibt den Gemeinden strategische Leitlinien vor, allerdings ist wenig darüber bekannt, wie die lokalen Ansätze tatsächlich aussehen. Bisher wurden vor allem Good Practice Sammlungen zum Thema veröffentlicht. Vor diesem Hintergrund beschäftigt sich die Dissertation detailliert mit der Stadtentwicklung für eine alternde Bevölkerung in solchen Gemeinden, die in sich zwar mit der Bevölkerungsalterung beschäftigen, aber nicht als Good Practice klassifiziert werden können. Die Hauptforschungsfrage ist: Wie planen lokale Akteure für eine alternde Bevölkerung? Die Arbeit folgt einem Grounded Theory Ansatz, der darauf zielt, theoretische Konzepte aus den empirischen Daten zu entwickeln. Lokale Governance und kollektives Lernen dienen als sensibilisierende Konzepte, d.h. weitergefasste theoretische Perspektiven. Aufgrund des Forschungsstandes und des Ziels, detailliertes Wissen über die Stadtentwicklung für eine alternde Bevölkerung zu gewinnen, folgt die Arbeit einem qualitativen Forschungsdesign. In den drei heterogenen Fallstudiengemeinden North Tyneside, Poole und Wealden wurden insbesondere qualitative Interviews mit lokalen Experten durchgeführt und Dokumente wie Strategiepapiere und Sitzungsprotokolle ausgewertet. Die Ergebnisse umfassen drei Themenbereiche. Zunächst werden lokale Governanceformen analysiert, was die Identifikation der beteiligten Akteure, ihre Handlungsorientierungen und Interaktionen umfasst. Da Ansätze zum Umgang mit der alternden Bevölkerung sich stark zwischen individuellen Akteuren unterscheiden, wurde auf dieser Basis eine Akteurstypologie erstellt. Darüber hinaus wird analysiert wie traditionale Steuerungsansätze staatlicher Akteure durch netzwerkartige Governanceformen ergänzt werden. Bedeutendstes Beispiel sind Arbeitsgruppen, in denen Akteure verschiedener Organisationen und Sektoren zusammenkommen, um Ansätze zum Umgang mit Senioren und der Bevölkerungsalterung zu entwickeln. Anschließend werden lokale Lernprozesse in der Planung für eine alternde Bevölkerung rekonstruiert. Dabei werden vier Phasen unterschieden: Agenda-Setting, Wissensaufbau, kollektives Lernen im engeren Sinne und Strategieerstellung. Es werden die Wechselwirkungen zwischen Governanceformen und kollektivem Lernen analysiert, insbesondere bezüglich der Lernformen in verschiedenen Typen von Arbeitsgruppen. Schließlich werden Herausforderungen und Perspektiven der Stadtentwicklung für eine alternde Bevölkerung diskutiert, die aus der Analyse von Governanceformen und Lernprozessen hervorgehen. Einerseits beziehen diese sich auf den Querschnittcharakter des Themas Alterung, andererseits auf den ambivalenten Einfluss der Nationalregierung. Die Alterung betrifft verschiedenste Bereiche lokaler Steuerung. Dies führt zu einer anhaltenden Suche nach lokalen Verantwortungsträgern und zu Schwierigkeiten, die Agenda über Gesundheit und Pflege Älterer hinaus zu erweitern. Darüber hinaus hat der Querschnittcharakter ein Experimentieren mit Governanceformen angeregt, sowie die Schaffung von mehr Partizipationsmöglichkeiten für ältere Bürger und die Erstellung ressortübergreifender lokaler Alterungsstrategien. Die starken Eingriffe der Nationalregierung in lokale Steuerungstätigkeiten befördern einerseits die Auseinandersetzung mit der Alterung, andererseits führen sie auch zu oberflächlichen und wenig nachhaltigen Reaktionen. Insgesamt bietet die Dissertation detailliertes empirisches Wissen zur Stadtentwicklung für eine alternde Bevölkerung. Die theoretischen Perspektiven lokale Governance und kollektives Lernen wurden genutzt um generalisierbare Ergebnisse aus den Erfahrungen in den drei Fallstudiengemeinden zu gewinnen. Abschließend werden Handlungsempfehlungen für Praktiker auf der lokalen und nationalen Ebene abgeleitet

In the post-war, post-independence period, India became a key site of intervention and experimentation for international population control advocates. During the 1950s, the Government of India became the first government to announce an official policy of population limitation as part of its first Five Year Plan in 1952, constituting its own national population as an object of study and intervention. The Khanna Study—a well-known population control experiment conducted in the Ludhiana District of Punjab—is emblematic of these processes. Between 1953 and 1960, Khanna was the site of population control experimentation for the Indian State and international organisations alike. Through a case study of the Khanna Study, this dissertation asks why India was so important to strategies of international population control and, conversely, why population control was so important to the newly-independent Government of India. I argue that international population control advocates focused on India because of the scale, poverty and—crucially—accessibility of its population. International organisations were able to experiment upon the Indian population primarily because of the collaboration of the Government of India. Population control was of mutual interest to international ‘overpopulation’ theorists and for Indian officials, who viewed population growth as an obstacle to economic development. In an attempt to render the Indian population legible and, therefore, amenable to population control interventions, these actors collaborated to make Khanna—and India generally—a laboratory for population control. Although the Khanna Study did not succeed in its stated goal of reducing the birth rate, it nevertheless helped to consolidate the position of population control as national policy, and produced Khanna as a study site to be re-visited and re-studied over the following five decades. As such, the Khanna Study itself helped to solidify the relationships between India and population control, and between international population control and India.

The majority of local areas in the UK are faced with an ageing population. Popular retirement destinations in coastal and more rural areas are particularly affected. The thesis aims to find out how local areas strategically tackle these demographic shifts. The British government has issued strategic guidance for local areas, but as yet little is known about how actual responses look. The literature has largely focused on good practice compilations. Consequently, the thesis attempts to analyse in depth local areas’ experiences in planning for an ageing population. The main research question is: How do local actors in the UK plan for population ageing? A grounded theory approach has been chosen to develop theoretical concepts from empirical data. Local governance and collective learning are used as sensitising concepts, i.e. wider theoretical perspectives. Due to the state of research and the aim to gather detailed knowledge regarding the planning for an ageing population in local areas, a qualitative research design has been chosen. More precisely, it is a multiple case study design, covering the three heterogeneous cases North Tyneside, Poole and Wealden. Empirical data has been assembled from qualitative interviews with local experts and documents such as local strategies or minutes of meetings. The results are threefold. Firstly, local governance arrangements are analysed. This covers the identification of involved actors, their action orientations and interactions. As approaches in planning for an ageing population differ across organisations, a typology of individual actors is developed. Moreover, it is observed that and analysed how traditional hierarchical steering by public bodies is complemented by more network-like forms of governance, for example multi-organisational older people’s partnerships. Secondly, local learning processes in planning for an ageing population are reconstructed. Four phases are differentiated: setting the agenda for the topic of ageing and older people followed by building up knowledge on the subject and collective learning in a narrower sense and, finally, strategy-making. Interrelations between governance arrangements and collective learning are analysed, particularly with respect to different forms of learning in different types of older people’s partnerships. Finally, central challenges and perspectives arising from the analysis of governance arrangements and learning processes are discussed. On the one hand, these pertain to the cross-cutting nature of ageing, on the other hand they are due to the ambivalent influence from national government on local areas. Ageing affects various spheres of local steering activity. Among the main implications for local areas in the UK are the continuous search for responsibility and the struggle to broaden the agenda beyond health and care. This has led to experimenting with governance structures, intensifying involvement of older people and developing inter-agency older people strategies and others as catalysts for further development. The strong influence from central government on local steering advances local reactions to ageing but provokes superficial and unsustainable answers at the same time. Overall, the thesis provides in-depth empirical knowledge on local planning for an ageing population. The theoretical lenses local governance and collective learning have been used to generalise from the practical experiences in the three case study areas. The thesis concludes with recommendations for practitioners locally and at the national level. These refer inter alia to local governance arrangements which come up to the issue’s cross-cuttingness and to national guidance and regulation which could facilitate their introduction or modification.:Figures and tables.......................................................................................................11 List of Abbreviations...................................................................................................13 1 Introduction..........................................................................................................15 1.1 Rationale and aims of the research.............................................................15 1.2 Study design...............................................................................................18 1.3 Thesis structure...........................................................................................20 2 Planning for an ageing population – a UK-wide overview...................................23 2.1 The UK’s ageing population........................................................................23 2.2 Local governance and planning in transition................................................30 2.3 Reactions to ageing in the UK.....................................................................38 2.4 Questions raised.........................................................................................46 3 Conceptual framework.........................................................................................49 3.1 Local planning for an ageing population – linked to various research areas.............................................................................................49 3.2 Grounded theory perspective......................................................................53 3.3 Sensitising concepts....................................................................................55 3.3.1 Local governance..................................................................................56 3.3.2 Collective learning.................................................................................62 3.4 Presuppositions guiding the analysis............................................................67 4 Research design and methods..............................................................................71 4.1 Overall research design................................................................................71 4.2 Exploratory interviews – national level.........................................................74 4.3 Sampling procedures...................................................................................75 4.3.1 Sampling of case study areas.................................................................76 4.3.2 Sampling of interviewees.......................................................................79 4.4 Data collection............................................................................................81 4.5 Data analysis...............................................................................................83 5 The case study areas.............................................................................................89 5.1 North Tyneside............................................................................................90 5.1.1 North Tyneside in profile.......................................................................90 5.1.2 Planning for an ageing population in North Tyneside............................91 5.2 Poole...........................................................................................................94 5.2.1 Poole in profile......................................................................................94 5.2.2 Planning for an ageing population in Poole...........................................96 5.3 Wealden/East Sussex...................................................................................98 5.3.1 Wealden/East Sussex in profile..............................................................98 5.3.2 Planning for an ageing population in Wealden/East Sussex.................100 5.4 Summary and arising questions.................................................................103 6 Local governance and planning for an ageing population...................................105 6.1 The involved actors...................................................................................105 6.1.1 Actors belonging to the public sector..................................................106 6.1.2 Actors belonging to the private sector.................................................116 6.1.3 Actors belonging to the voluntary and community sector....................117 6.1.4 Connecting the sectors: The Local Strategic Partnership......................122 6.2 A typology of actors..................................................................................125 6.3 Governance arrangements: from working in silos to partnerships...............130 6.4 Summary...................................................................................................139 7 Local learning processes in planning for an ageing population..........................141 7.1 Setting the ageing agenda.........................................................................143 7.1.1 Awareness of the ageing population...................................................143 7.1.2 From awareness to action....................................................................146 7.2 Building up knowledge of ageing..............................................................149 7.2.1 Basing planning on (demographic) evidence.......................................149 7.2.2 Older people’s participation.................................................................155 7.2.3 Reacting to stimuli from national government.....................................158 7.3 Collective learning to plan for an ageing population..................................160 7.3.1 Collective learning in the local area.....................................................160 7.3.2 Learning in older people’s partnerships................................................164 7.4 Strategy-making for an ageing population.................................................171 7.4.1 Local strategies for dealing with population ageing.............................171 7.4.2 National trends reflected in local strategies..........................................178 7.4.3 The functions of strategies and strategy-making.................................187 7.5 Summary...................................................................................................191 8 Central challenges and perspectives in planning for an ageing population........193 8.1 The cross-cutting nature of ageing............................................................193 8.1.1 Searching for responsibility..................................................................194 8.1.2 Struggling to broaden the agenda.......................................................195 8.1.3 Experimenting with governance structures..........................................196 8.1.4 Involving older people.........................................................................197 8.1.5 Using strategies as catalysts................................................................198 8.2 Ambivalent influence from national government.......................................199 8.2.1 Influence via funding, instruments, targets and supervision.................200 8.2.2 Skipping the regional level..................................................................203 8.2.3 National government stimulating local areas to plan for an ageing population...............................................................................204 8.2.4 Local areas’ superficial reactions to national government influence......205 8.3 Regional and local challenges and perspectives..........................................207 9 Discussion of the results and implications..........................................................209 9.1 Summary of results....................................................................................209 9.2 Reflection of the results and the research design with respect to the state of research..............................................................................213 9.2.1 Discussion of the results......................................................................214 9.2.2 Discussion of the research design........................................................217 9.3 Open questions and need for further research...........................................219 9.4 Recommended action................................................................................221 9.5 Looking beyond the UK.............................................................................228 Literature..................................................................................................................231 Appendix..................................................................................................................251 A Interviewees and their positions..........................................................................251 B Exemplary e-mail to get into contact with potential interviewee and accompanying project outline..............................................................................252 C Interview guideline..............................................................................................254 D Transcription rules according to GAT 2 (modified)...............................................259
Die Mehrzahl britischer Gemeinden ist mit einer alternden Bevölkerung konfrontiert. Küstengebiete und ländliche Räume sind besonders betroffen, da sie als Altersruhesitz bevorzugt werden. Ziel der Dissertation ist es, den strategischen Umgang der Gemeinden mit diesen demographischen Veränderungen zu beleuchten. Die britische Nationalregierung gibt den Gemeinden strategische Leitlinien vor, allerdings ist wenig darüber bekannt, wie die lokalen Ansätze tatsächlich aussehen. Bisher wurden vor allem Good Practice Sammlungen zum Thema veröffentlicht. Vor diesem Hintergrund beschäftigt sich die Dissertation detailliert mit der Stadtentwicklung für eine alternde Bevölkerung in solchen Gemeinden, die in sich zwar mit der Bevölkerungsalterung beschäftigen, aber nicht als Good Practice klassifiziert werden können. Die Hauptforschungsfrage ist: Wie planen lokale Akteure für eine alternde Bevölkerung? Die Arbeit folgt einem Grounded Theory Ansatz, der darauf zielt, theoretische Konzepte aus den empirischen Daten zu entwickeln. Lokale Governance und kollektives Lernen dienen als sensibilisierende Konzepte, d.h. weitergefasste theoretische Perspektiven. Aufgrund des Forschungsstandes und des Ziels, detailliertes Wissen über die Stadtentwicklung für eine alternde Bevölkerung zu gewinnen, folgt die Arbeit einem qualitativen Forschungsdesign. In den drei heterogenen Fallstudiengemeinden North Tyneside, Poole und Wealden wurden insbesondere qualitative Interviews mit lokalen Experten durchgeführt und Dokumente wie Strategiepapiere und Sitzungsprotokolle ausgewertet. Die Ergebnisse umfassen drei Themenbereiche. Zunächst werden lokale Governanceformen analysiert, was die Identifikation der beteiligten Akteure, ihre Handlungsorientierungen und Interaktionen umfasst. Da Ansätze zum Umgang mit der alternden Bevölkerung sich stark zwischen individuellen Akteuren unterscheiden, wurde auf dieser Basis eine Akteurstypologie erstellt. Darüber hinaus wird analysiert wie traditionale Steuerungsansätze staatlicher Akteure durch netzwerkartige Governanceformen ergänzt werden. Bedeutendstes Beispiel sind Arbeitsgruppen, in denen Akteure verschiedener Organisationen und Sektoren zusammenkommen, um Ansätze zum Umgang mit Senioren und der Bevölkerungsalterung zu entwickeln. Anschließend werden lokale Lernprozesse in der Planung für eine alternde Bevölkerung rekonstruiert. Dabei werden vier Phasen unterschieden: Agenda-Setting, Wissensaufbau, kollektives Lernen im engeren Sinne und Strategieerstellung. Es werden die Wechselwirkungen zwischen Governanceformen und kollektivem Lernen analysiert, insbesondere bezüglich der Lernformen in verschiedenen Typen von Arbeitsgruppen. Schließlich werden Herausforderungen und Perspektiven der Stadtentwicklung für eine alternde Bevölkerung diskutiert, die aus der Analyse von Governanceformen und Lernprozessen hervorgehen. Einerseits beziehen diese sich auf den Querschnittcharakter des Themas Alterung, andererseits auf den ambivalenten Einfluss der Nationalregierung. Die Alterung betrifft verschiedenste Bereiche lokaler Steuerung. Dies führt zu einer anhaltenden Suche nach lokalen Verantwortungsträgern und zu Schwierigkeiten, die Agenda über Gesundheit und Pflege Älterer hinaus zu erweitern. Darüber hinaus hat der Querschnittcharakter ein Experimentieren mit Governanceformen angeregt, sowie die Schaffung von mehr Partizipationsmöglichkeiten für ältere Bürger und die Erstellung ressortübergreifender lokaler Alterungsstrategien. Die starken Eingriffe der Nationalregierung in lokale Steuerungstätigkeiten befördern einerseits die Auseinandersetzung mit der Alterung, andererseits führen sie auch zu oberflächlichen und wenig nachhaltigen Reaktionen. Insgesamt bietet die Dissertation detailliertes empirisches Wissen zur Stadtentwicklung für eine alternde Bevölkerung. Die theoretischen Perspektiven lokale Governance und kollektives Lernen wurden genutzt um generalisierbare Ergebnisse aus den Erfahrungen in den drei Fallstudiengemeinden zu gewinnen. Abschließend werden Handlungsempfehlungen für Praktiker auf der lokalen und nationalen Ebene abgeleitet.:Figures and tables.......................................................................................................11 List of Abbreviations...................................................................................................13 1 Introduction..........................................................................................................15 1.1 Rationale and aims of the research.............................................................15 1.2 Study design...............................................................................................18 1.3 Thesis structure...........................................................................................20 2 Planning for an ageing population – a UK-wide overview...................................23 2.1 The UK’s ageing population........................................................................23 2.2 Local governance and planning in transition................................................30 2.3 Reactions to ageing in the UK.....................................................................38 2.4 Questions raised.........................................................................................46 3 Conceptual framework.........................................................................................49 3.1 Local planning for an ageing population – linked to various research areas.............................................................................................49 3.2 Grounded theory perspective......................................................................53 3.3 Sensitising concepts....................................................................................55 3.3.1 Local governance..................................................................................56 3.3.2 Collective learning.................................................................................62 3.4 Presuppositions guiding the analysis............................................................67 4 Research design and methods..............................................................................71 4.1 Overall research design................................................................................71 4.2 Exploratory interviews – national level.........................................................74 4.3 Sampling procedures...................................................................................75 4.3.1 Sampling of case study areas.................................................................76 4.3.2 Sampling of interviewees.......................................................................79 4.4 Data collection............................................................................................81 4.5 Data analysis...............................................................................................83 5 The case study areas.............................................................................................89 5.1 North Tyneside............................................................................................90 5.1.1 North Tyneside in profile.......................................................................90 5.1.2 Planning for an ageing population in North Tyneside............................91 5.2 Poole...........................................................................................................94 5.2.1 Poole in profile......................................................................................94 5.2.2 Planning for an ageing population in Poole...........................................96 5.3 Wealden/East Sussex...................................................................................98 5.3.1 Wealden/East Sussex in profile..............................................................98 5.3.2 Planning for an ageing population in Wealden/East Sussex.................100 5.4 Summary and arising questions.................................................................103 6 Local governance and planning for an ageing population...................................105 6.1 The involved actors...................................................................................105 6.1.1 Actors belonging to the public sector..................................................106 6.1.2 Actors belonging to the private sector.................................................116 6.1.3 Actors belonging to the voluntary and community sector....................117 6.1.4 Connecting the sectors: The Local Strategic Partnership......................122 6.2 A typology of actors..................................................................................125 6.3 Governance arrangements: from working in silos to partnerships...............130 6.4 Summary...................................................................................................139 7 Local learning processes in planning for an ageing population..........................141 7.1 Setting the ageing agenda.........................................................................143 7.1.1 Awareness of the ageing population...................................................143 7.1.2 From awareness to action....................................................................146 7.2 Building up knowledge of ageing..............................................................149 7.2.1 Basing planning on (demographic) evidence.......................................149 7.2.2 Older people’s participation.................................................................155 7.2.3 Reacting to stimuli from national government.....................................158 7.3 Collective learning to plan for an ageing population..................................160 7.3.1 Collective learning in the local area.....................................................160 7.3.2 Learning in older people’s partnerships................................................164 7.4 Strategy-making for an ageing population.................................................171 7.4.1 Local strategies for dealing with population ageing.............................171 7.4.2 National trends reflected in local strategies..........................................178 7.4.3 The functions of strategies and strategy-making.................................187 7.5 Summary...................................................................................................191 8 Central challenges and perspectives in planning for an ageing population........193 8.1 The cross-cutting nature of ageing............................................................193 8.1.1 Searching for responsibility..................................................................194 8.1.2 Struggling to broaden the agenda.......................................................195 8.1.3 Experimenting with governance structures..........................................196 8.1.4 Involving older people.........................................................................197 8.1.5 Using strategies as catalysts................................................................198 8.2 Ambivalent influence from national government.......................................199 8.2.1 Influence via funding, instruments, targets and supervision.................200 8.2.2 Skipping the regional level..................................................................203 8.2.3 National government stimulating local areas to plan for an ageing population...............................................................................204 8.2.4 Local areas’ superficial reactions to national government influence......205 8.3 Regional and local challenges and perspectives..........................................207 9 Discussion of the results and implications..........................................................209 9.1 Summary of results....................................................................................209 9.2 Reflection of the results and the research design with respect to the state of research..............................................................................213 9.2.1 Discussion of the results......................................................................214 9.2.2 Discussion of the research design........................................................217 9.3 Open questions and need for further research...........................................219 9.4 Recommended action................................................................................221 9.5 Looking beyond the UK.............................................................................228 Literature..................................................................................................................231 Appendix..................................................................................................................251 A Interviewees and their positions..........................................................................251 B Exemplary e-mail to get into contact with potential interviewee and accompanying project outline..............................................................................252 C Interview guideline..............................................................................................254 D Transcription rules according to GAT 2 (modified)...............................................259

An empirical study presenting the social and economic proof of a global shift from a bipolar economic world to a multipolar economic world. The time period for data and projections is 2010 to 2050. The measurements used are population pyramids, total population, GDP per capita, and total GDP.

Breast cancer is the leading cause of death among Latinas women. Several barriers persist when accessing health care and utilization of healthcare services such as annual mammograms, leading to a late stage diagnosis or death related to breast cancer illness. The purpose of this study was to examine disparities in breast cancer experiences within Latina communities in the United States. The Health Belief Model served as the foundation of this qualitative grounded theory study. The research questions explored; access to breast care services that encourage early breast cancer detection; breast care diagnostics such as exams, mammograms and biopsies; and views of availability to breast care exams, diagnostics and treatment options improving health outcomes. The participants were females who self-identified as Hispanic and 19 years of age or older and resided in north east part of the United States. Participants must have discovered a breast tumor, engaged in the decision-making process to seek biopsy, and had a breast cancer diagnosis. A total of 12 Latina women were recruited for 60 minutes recorded interviews Later, the interviews were transcribed.. Findings of the study showed the participants perceived the disease as serious leading to death; cultural context, insurance status may not have contributed to susceptibility to the disease. This study benefits Latina women, and other vulnerable female populations in the United States diagnosed with breast cancer. The social change implications of the study can influence program initiatives that seek to improve equitable access to care, breast care services and the quality of life. It provides insight to practice approaches regarding access to care, service utilization, and development of program initiatives.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2007.
This project was initiated to develop a new and novel approach to address complex sequencing problems, in particular, an alternative method was developed to find solutions to the sequential ordering problem. The sequential ordering problem is concerned with the arrangement of a number of elements in a sequence that respects a number of precedence constraints and results in the lowest overall cost. A precedence constraint requires that some element will occur before another in the solution sequence, and the cost of a solution is determined by summing the independent individual costs that are incurred when progressing from one specific element in the solution sequence to another. Instances of this problem are regularly found in the practice of industrial engineering in problems such as the routing of a delivery vehicle, the scheduling of jobs on a machine and the preparation of project plans with limited resources. The sequential ordering problem is known to be complex in the sense that as the size of problem instances increases, the best-known time required to find a guaranteed optimal solution increases exponentially.

In this thesis we discuss the synchronization of stochastic population oscillators in ecology and neuroscience. Traditionally, the synchronization of oscillators has been studied in deterministic systems with various modes of synchrony induced by coupling between the oscillators. However, recent developments have shown that an ensemble of uncoupled oscillators can be synchronized by a common noise source alone. By considering the effects of noise-induced synchronization on biological oscillators, we are able to explain various biological phenomena in ecological and neurobiological contexts - most importantly, the long-observed Moran effect. Our formulation of the systems as limit cycle oscillators arising from populations of individuals, each with a random element to its behaviour, also allows us to examine the interaction between an external noise source and this intrinsic stochasticity. This provides possible explanations as to why in ecological systems large-amplitude cycles may not be observed in the wild. In neural population oscillators, we were able to observe not just synchronization, but also clustering in some pa- rameter regimes. Finally, we are also able to extend our methods to include coupling in our models. In particular, we examine the competing effects of dispersal and extrinsic noise on the synchronization of a pair of Rosenzweig-Macarthur predator-prey systems. We discover that common environmental noise will ultimately synchronize the oscillators, but that the approach to synchrony depends on whether or not dispersal in the absence of noise supports any stable asynchronous states. We also show how the combination of correlated (shared) and uncorrelated (unshared) noise with dispersal can lead to a multistable steady-state probability density. Similar analysis on a coupled system of neural oscillators would be an interesting project for future work, which, among other future directions of research, is discussed in the concluding section of this thesis.

La population - en son sens originel de processus de peuplement - est un sujet étonnamment absent de l'énorme volume d’études sur Adam Smith. Ce thème était au centre de la philosophie morale et de l'économie politique du 18e siècle, les deux domaines auxquels les contributions de Smith sont les plus connues. Son importance dans l’œuvre de Smith a été obscurcie au 20e siècle par une focalisation étroite sur les questions économiques dans la littérature secondaire. Pour une analyse intégrale de son œuvre, il est essentiel que la place centrale du peuplement soit révélée. Trois thèmes aujourd'hui considérés comme essentiels au projet de Smith sont ainsi intimement liés à la population : le lien entre division du travail et étendue du marché ; la théorie des quatre stades du progrès de la société ; et le lien entre développement rural et urbain, lui-même au centre du plaidoyer de Smith pour la liberté du commerce. Le marché est un concept aujourd'hui assimilé au fonctionnement du système économique capitaliste ; pour Smith, il décrivait la faculté de commercer, aux vecteurs essentiellement démographiques et géographiques. Le progrès de la société est à la fois cause et effet de la croissance de la population. En son sein se trouve l'interrelation symbiotique entre le développement rural et urbain que Smith appelait le «progrès naturel de l'opulence». Adopter l’optique smithienne plutôt que néo-malthusienne dans l'examen des dynamiques de population et de développement - y compris l'analyse de la transition démographique - conduit alors à une reconsidération fondamentale des interactions causales entre mortalité, fécondité, richesse et variables institutionnelles
Population - in its original sense of the process of peopling - is a topic surprisingly absent from the huge volume of scholarship on Adam Smith. This topic was central to 18th century moral philosophy and political economy, the two fields Smith most famously contributed to. Its importance in Smith’s work was obscured in the 20th century by a narrow focus on economic matters in the secondary literature. For an undivided analysis of Smith’s oeuvre it is crucial that the central position of the peopling process be brought to light. Three topics that are today recognised as essential to Smith’s project are thus intimately connected to population: the relation between the division of labour and the extent of the market; the stadial theory of progress; and the link between the development of town and country, itself central to Smith’s advocacy of the freedom of trade. The market is a concept read today through an institutional lens linking it to the functioning of the capitalist economic system; Smith conceived of it as facility for trade, with essentially demographic and geographic vectors. The progress of society is both cause and effect of the growth of population. At its core is the symbiotic interrelationship between rural and urban development that Smith called the “natural progress of opulence”. In turn, looking at dynamics of population and development - including the analysis of the demographic transition - through a Smithian rather than a neo-Malthusian lens leads to a fundamental reconsideration of causal interactions between mortality, fertility, wealth and institutional variables

In this thesis, both theoretical and application oriented results are obtained for differential equations with discontinuities of different types: impulsive differential equations, differential equations with piecewise constant argument of generalized type and differential equations with discontinuous right-hand sides. Several qualitative problems such as stability, Hopf bifurcation, center manifold reduction, permanence and persistence are addressed for these equations and also for Lotka-Volterra predator-prey models with variable time of impulses, ratio-dependent predator-prey systems and logistic equation with piecewise constant argument of generalized type. For the first time, by means of Lyapunov functions coupled with the Razumikhin method, sufficient conditions are established for stability of the trivial solution of differential equations with piecewise constant argument of generalized type. Appropriate examples are worked out to illustrate the applicability of the method. Moreover, stability analysis is performed for the logistic equation, which is one of the most widely used population dynamics models. The behaviour of solutions for a 2-dimensional system of differential equations with discontinuous right-hand side, also called a Filippov system, is studied. Discontinuity sets intersect at a vertex, and are of the quasilinear nature. Through the B&
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equivalence of that system to an impulsive differential equation, Hopf bifurcation is investigated. Finally, the obtained results are extended to a 3-dimensional discontinuous system of Filippov type. After the existence of a center manifold is proved for the 3-dimensional system, a theorem on the bifurcation of periodic solutions is provided in the critical case. Illustrative examples and numerical simulations are presented to verify the theoretical results.

Statistical aspects of the population regulation of a migratory brown trout population are investigated. The life cycle of the trout, the study area and the sampling routine are described in Chapter 1. Models of numerical changes in fish populations are reviewed in Chapter 2. Measures that assess the nonlinear behaviour of nonlinear regression models are described in Chapter 3. The additive error Ricker model describes the relationship between the number of 0+ parr in May/June and the number of eggs. The nonlinear behaviour of the model is investigated in Chapter 4. The parameter effects nonlinearity of the model is reduced by a reparameterisation. Chapter 5 investigates the effect of errors in the egg variable on the distributions of the least squares estimators of the additive error and the multiplicative error Ricker models. The errors-in-variables considerably increase the variances of the least squares estimators. Models of the relationships between the numbers of 0+ parr in August/September, the number of 1+ parr, the egg production of a year class and the number of eggs are developed in Chapter 6. These models account for the effect of summer drought on survival. Survival is density dependent during the first summer of the life cycle and density independent thereafter. Standard measures of nonlinearity can seriously underestimate the nonlinear behaviour of piecewise linear change-point models. New measures of nonlinearity appropriate for piecewise linear change-point models are developed in Chapter 7. Chapter 8 develops a model of the growth of brown trout fed on maximum rations as a function of time, body weight and water temperature. Chapter 9 develops a model that relates the survival rate of 0+ parr between May/June and August/September to the length distribution of the trout in May/June. The results of the Thesis are discussed in Chapter 10.

The purpose of this study was to understand earned income tax credit (EITC) policy influences on the development of economic mobility for individuals receiving EITC. Policymakers have declared that improving the economic mobility of low-wage workers a major objective of the EITC. This study addressed identifying factors that contribute to economic mobility, and testing the punctuated equilibrium theory to determine whether exogenous forces influence EITC policymakers' decisions.

Utilizing the survey data of 2,252 EITC respondents from the Legal Aid Society of Orange County, California, the study found that saving, education, race, and being banked were factors contributing to economic mobility. Age was not a factor contributing to economic mobility. Results from testing the punctuated equilibrium theory indicated that at the .05 level there was not a significant association between exogenous forces and EITC policymaking decisions.

This thesis focus on the effect that selection has on the ancestry of a spatially structured population. In the absence of selection, the ancestry of a sample from the population behaves as a system of random walks that coalesce upon meeting. Backwards in time, each ancestral lineage jumps, at the time of its birth, to the location of its parent, and whenever two ancestral lineages have the same parent they jump to the same location and coalesce. Introducing selective forces to the evolution of a population translates into branching when we follow ancestral lineages, a by-product of biased sampling forwards in time. We study populations that evolve according to the Spatial Lambda-Fleming-Viot process with selection. In order to assess whether the picture under selection differs from the neutral case we must consider the timescale dictated by the neutral mutation rate Theta. Thus we look at the rescaled dual process with n=1/Theta. Our goal is to find a non-trivial rescaling limit for the system of branching and coalescing random walks that describe the ancestral process of a population. We show that the strength of selection (relative to the mutation rate) required to do so depends on the dimension; in one and two dimensions selection needs to be stronger in order to leave a detectable trace in the population. The main results in this thesis can be summarised as follows. In dimensions three and higher we take the selection coefficient to be proportional to 1/n, in dimension two we take it to be proportional to log(n)/n and finally, in dimension one we take the selection coefficient to be proportional to 1/sqrt(n). We then proceed to prove that in two and higher dimensions the ancestral process of a sample of the population converges to branching Brownian motion. In one dimension, provided we do not allow ancestral lineages to jump over each other, the ancestral process converges to a subset of the Brownian net. We also provide numerical results that show that the non-crossing restriction in one dimension cannot be lifted without a qualitative change in the behaviour of the process. Finally, through simulations, we study the rate of convergence in the two-dimensional case.

Population coding—the transmission of information by the combined activity of many neurons—is a feature of many neural systems. Identifying the role played by individual neurons within a population code is vital for the understanding of neural codes. In this thesis I examine which stimuli are best encoded by a given neuron within a population and how this depends on the informational measure used, on commonly-measured neuronal properties, and on the population size and the spacing between stimuli. I also show how correlative measures of topography can be used to test for significant topography in the anatomical arrangement of arbitrary neuronal properties. The neurons involved in a population code are generally clustered together in one region of the brain, and moreover their response selectivity is often reflected in their anatomical arrangement within that region. Although such topographic maps are an often-encountered feature in the brains of many species, there are no standard, objective procedures for quantifying topography. Topography in neural maps is typically identified and described subjectively, but in cases where the scale of the map is close to the resolution limit of the measurement technique, identifying the presence of a topographic map can be a challenging subjective task. In such cases, an objective statistical test for detecting topography would be advantageous. To address these issues, I assess seven measures by quantifying topography in simulated neural maps, and show that all but one of these are effective at detecting statistically significant topography even in weakly topographic maps. The precision of the neural code is commonly investigated using two different families of statistical measures: (i) Shannon mutual information and derived quantities when investigating very small populations of neurons and (ii) Fisher information when studying large populations. The Fisher information always predicts that neurons convey most information about stimuli coinciding with the steepest regions of the tuning curve, but it is known that information theoretic measures can give very different predictions. Using a Monte Carlo approach to compute a stimulus-specific decomposition of the mutual information (the stimulus-specific information, or SSI) for populations up to hundreds of neurons in size, I address the following questions: (i) Under what conditions can Fisher information accurately predict the information transmitted by a neuron within a population code? (ii) What are the effects of level of trial-to-trial variability (noise), correlations in the noise, and population size on the best-encoded stimulus? (iii) How does the type of task in a behavioural experiment (i.e. fine and coarse discrimination, classification) affect the best-encoded stimulus? I show that, for both unimodal and monotonic tuning curves, the shape of the SSI is dependent upon trial-to-trial variability, population size and stimulus spacing, in addition to the shape of the tuning curve. It is therefore important to take these factors into account when assessing which stimuli a neuron is informative about; just knowing the tuning curve may not be sufficient.

Genome-wide association studies (GWAS) have greatly improved our understanding of the genetic basis of complex traits. However, there are two major limitations with GWAS. First, most common variants identified by GWAS individually or in combination explain only a small proportion of heritability. This raises the possibility that additional forms of genetic variation, such as rare variants, could contribute to the missing heritability. The second limitation is that GWAS typically cannot identify which genes are being affected by the associated variants. Examination of rare variants, especially those in coding regions of the genome, can help address these issues. Moreover, several studies have recently identified low-frequency variants at both known and novel loci associated with complex traits, suggesting that functionally significant rare variants exist in the human population.

In the context of ecological risk assessment of chemicals, individual-based population models hold great potential to increase the ecological realism of current regulatory risk assessment procedures. However, developing and parameterizing such models is time-consuming and often ad hoc. Using standardized, tested submodels of individual organisms would make individual-based modelling more efficient and coherent. In this thesis, I explored whether Dynamic Energy Budget (DEB) theory is suitable for being used as a standard submodel in individual-based models, both for ecological risk assessment and theoretical population ecology. First, I developed a generic implementation of DEB theory in an individual-based modeling (IBM) context: DEB-IBM. Using the DEB-IBM framework I tested the ability of the DEB theory to predict population-level dynamics from the properties of individuals. We used Daphnia magna as a model species, where data at the individual level was available to parameterize the model, and population-level predictions were compared against independent data from controlled population experiments. We found that DEB theory successfully predicted population growth rates and peak densities of experimental Daphnia populations in multiple experimental settings, but failed to capture the decline phase, when the available food per Daphnia was low. Further assumptions on food-dependent mortality of juveniles were needed to capture the population dynamics after the initial population peak. The resulting model then predicted, without further calibration, characteristic switches between small- and large-amplitude cycles, which have been observed for Daphnia. We conclude that cross-level tests help detecting gaps in current individual-level theories and ultimately will lead to theory development and the establishment of a generic basis for individual-based models and ecology. In addition to theoretical explorations, we tested the potential of DEB theory combined with IBMs to extrapolate effects of chemical stress from the individual to population level. For this we used information at the individual level on the effect of 3,4-dichloroanailine on Daphnia. The individual data suggested direct effects on reproduction but no significant effects on growth. Assuming such direct effects on reproduction, the model was able to accurately predict the population response to increasing concentrations of 3,4-dichloroaniline. We conclude that DEB theory combined with IBMs holds great potential for standardized ecological risk assessment based on ecological models.
Für die ökologische Risikobewertung von Chemikalien sind individuenbasierte Populationsmodelle ein vielversprechendes Werkzeug um heutige Bewertungen ökologisch realistischer zu gestalten. Allerdings ist die Entwicklung und Parametrisierung derartiger Modelle zeitaufwendig und oft wenig systematisch. Standardisierte, geprüfte Untermodelle, die Einzelorganismen beschreiben, würden die individuenbasierte Modellierung effizienter und kohärenter machen. In meiner Dissertation habe ich daher untersucht, inwieweit sich die Dynamic Energy Budget-Theorie (DEB) als Standardmodell innerhalb individuenbasierter Populationsmodelle eignet, und zwar sowohl für die ökologische Risikobewertung als auch für die theoretische Populationsökologie. Zunächst habe ich eine generische Implementierung der DEB-Theorie im Rahmen individuenbasierter Modellen (IBM) erstellt: DEB-IBM. Dieses Werkzeug nutzend habe ich dann untersucht, ob es mit Hilfe der DEB-Theorie gelingt, ausgehend von den Eigenschaften und Aktivitäten einzelner Individuen, Populationsdynamik vorherzusagen. Wir nutzten dabei Daphnia magna als Modellart, für die Daten auf der Individuenebene verfügbar waren, um das Modell zu parametrisieren, sowie Populationsdaten, mit denen Modellvorhersagen verglichen werden konnten. DEB-Theorie war in der Lage, beobachtete Populationswachstumsraten sowie die maximalen Abundanzen korrekt vorherzusagen, und zwar für verschiedene Umweltbedingungen. Für Phasen des Rückgangs der Population allerdings, wenn die für die Daphnien verfügbare Nahrungsmenge gering war, kam es zu Abweichungen. Es waren deshalb zusätzliche Annahmen über nahrungsabhängige Sterblichkeit von juvenilen Daphnien erforderlich, um die gesamte Populationsdynamik korrekt vorherzusagen. Das resultierende Modell konnte dann, ohne weitere Kalibrierungen, den für Daphnien charakteristischen Wechsel zwischen Populationszyklen mit großen und kleinen Amplituden richtig vorhersagen. Wir folgern daraus, daß Ebenen übergreifende Tests dabei helfen, Lücken in aktuellen Theorien über Einzelorganismen aufzudecken Dies trägt zur Theorieentwicklung bei und liefert Grundlagen für individuenbasierte Modellierung und Ökologie. Über diese Grundlagenfragen hinaus haben wir überprüft, ob DEB-Theorie in Kombination mit IBMs es ermöglicht, den Effekt von chemischem Streß auf Individuen auf die Populationsebene zu extrapolieren. Wir nutzten Daten über die Auswirkungen von 3,4 Dichloroanalin auf einzelne Daphnien, die zeigten daß im Wesentlichen die Reproduktion, nicht aber das Wachstum beeinträchtigt ist. Mit entsprechenden Annahmen konnte unser Modell den Effekt auf Populationsebene, für den unabhängige Daten vorlagen, korrekt vorhersagen. DEB-Theorie in Kombination mit individuenbasierter Modellierung birgt somit großes Potential für einen standardisierten modellbasierten Ansatz in der ökologischen Risikobewertung von Chemikalien.

In this thesis, a model is developed for a finite population queueing system deployed to meet a constant demand for the situation where failed units require a single spare part to initiate repair action. A supporting inventory of spare parts is included in the model operating under a one-for-one ordering policy. The system was modeled as a Markov process, and an algorithm is presented that numerically evaluates the steady state probabilities. Cost was chosen as the measure of effectiveness of the system. Total system cost consists of shortage costs for not being able to meet the demand for units, population and repair facility annual equivalent costs, holding costs for keeping spare parts in inventory, and procurement and spare part costs related to procurement and purchase activities. A computer program in BASIC, designed for a microcomputer, enables the decision maker to interactively find the design that optimizes the effectiveness measure of the system. The decision variables considered are the number of units in the population, the number of repair channels, and the maximum level of spare parts. One specific design problem is presented.
M.S.

Darwin's (1859) theory of evolution by natural selection accounts for the adaptations of organisms, but, as Fisher (1930) famously said, 'natural selection is not evolution.' Evolutionary theory has two major components: i) natural selection, which involves the underlying dynamics of populations; and ii) adaptive evolutionary change, which involves the optimisation of phenotypes for fitness maximisation. Many of the traditional theoretical frameworks in evolutionary theory have focussed on studying optimisation processes that generate biological adaptations. In recent years, however, a number of evolutionary theorists have turned to using frameworks such as the 'replicator dynamics' or 'eco-evolutionary dynamics', to explore the dynamics of natural selection. There has, however, been little attempt to explore how these dynamical systems frameworks relate to more traditional frameworks in evolutionary theory or how they incorporate the principles that embody the process of evolution by natural selection, namely, phenotypic variation, differential reproductive success, and heritability. In this thesis, I use these principles to provide the formal foundations of a general framework - a mathematical synthesis - in which the future state of an evolutionary system can be predicted from its present state; what I will call a 'dynamical systems theory of natural selection.' Given the state of an existing biological system, and a set of assumptions about how individuals within the system interact, the job of the dynamical systems theory of natural selection is no less than to predict the future in its entirety.