Dissertations / Theses on the topic 'Populations marginales'

L’encadrement de la population, une des principales obsessions de l’Etat sous l’Ancien Régime, a nécessité la constitution d’un maillage juridictionnel complexe et dense du territoire. Le littoral breton au XVIIIe siècle apparaît comme un bon observatoire des rapports entre les habitants de cet espace et les représentants de l’ordre. Ce territoire offre de multiples opportunités aux populations locales et aux migrants. Il devient un espace particulièrement attractif qu’il est nécessaire de contrôler. Le maillage juridictionnel permet de capter une population qualifiée de marginale. Des formes spécifiques de criminalité se développant sur le littoral peuvent être décelées. Ce sont surtout des hommes jeunes au statut précaire qui apparaissent dans les archives. Face au juge, ils revendiquent la pratique d’activités illicites telles que la mendicité ou la contrebande. La figure du migrant-mendiant est particulièrement prégnante. Les représentations de la marginalité laissent transparaître une volonté de mise à l’écart des pauvres par les élites (déportation, enfermement). Pourtant, les archives permettent de souligner les liens de solidarités qui existent entre l’individu incriminé et sa famille. Le curé ou l’employeur sont également de potentiels soutiens. L’exclusion est donc un état temporaire. Une intégration par le recours à la pluriactivité est possible, permettant aux plus humbles de survivre ou d’obtenir un revenu complémentaire. La pluriactivité, intégrée dans les usages, souligne les potentialités du littoral et nuance la notion d’exclusion
Supervision of the population, one of the main obsessions of the State during the Ancien Régime, required the creation of a complex and dense jurisdictional network on French territory. The coast of Brittany during the eighteenth century seems to be a good place to examine and analyze the relationship between the people who live in the area and State officials. Its attractiveness which lays in the many activities it can offer to locals and migrants make controlling it a necessity. The jurisdictional network points out a population which is qualified as marginal. Specific forms of criminality can be detected. Young men with a precarious status appear in the archives. In front of the judge, they claim illicit activities like begging or smuggling. The figure of the migrant-beggar is particularly pregnant. The representations of marginality show intentional isolation of the poor from the elite (deportation, confinement). Nevertheless, the archives allow one to underline the links of solidarity which exist between the individual and his family. The priest or the employer are also a potential means of support. Exclusion is therefore a temporary state. Integration by resorting to pluriactivity is possible, allowing poor people to survive or to obtain a complementary income. Pluriactivity, integrated in the customs, shows the potentiality of the coast of Brittany and qualifies the different degrees of the notion of exclusion

Fruit de recherches en géographie urbaine et sociale, cette thèse propose une analyse des phénomènes de précarité et de leur traitement dans le cadre de ce que l'on appelle communément les politiques de la ville et du développement social urbain. L'échelle retenue est l'agglomération rennaise, terrain d'expérimentation particulièrement riche en la matière et dont les résultats sont bien souvent reconnus et salués. L'auteur mobilise une approche multi-référentielle et multi-dimensionnelle en proposant différents niveaux d'analyse ce qui le conduit a formaliser des processus modélisables construits dans le but d'interpréter les phénomènes de l'intégration et de la ségrégation, d'expliquer les mécanismes générateurs d'urbanité, de comprendre enfin les logiques d'action qui s'expriment dans la conquête la citoyenneté ou la rébellion urbaine. Rappelant quelques données essentielles concernant l'histoire du logement social afin de situer la proclamation du droit au logement comme l'aboutissement d'une succession de politiques et de mouvements sociaux, il porte un intérêt particulier aux réalisations rennaises en matière de relogement ou de création d'habitats adaptés. Tout d'abord, il étudie la distribution spatiale des populations en utilisant l'analyse comparative et l'analyse multivariée. Il tente en particulier de tester des outils permettant d'appréhender la structure résidentielle d'une ville et de caractériser les phénomènes de pauvreté urbaine. Il examine ensuite les politiques de développement social urbain menées localement au cours des années quatre-vingts afin de caractériser l'intervention des acteurs impliques dans la création, la réhabilitation et la gestion du logement social. Etudiant enfin, les itinéraires socio-residentiels d'individus et de familles en situation précaire il met en évidence la diversité et l'évolutivité de leurs situations et le caractère aléatoire de l'effet des politiques d'intégration
This thesis, drawing on research in urban social geography, analyses deprivation and its treatment within the framework of French urban and social development policies. The French city of Rennes including its surrouding urban district was chosen for study, since it is of a suitable size and has been particularly active and renowned for its policy and results in this area. A multifaceted and cross-disciplinary study of the phenomenon was carried out, analysis being undertaken at different levels, and models of the different processes involved were constructed. These models were then used to interpret the phenomena of integration and segregation, to explain the mechanisms involved in the creation of the fabric of an urban community and to understand the logic behind the behaviour expressed in the struggle for urban citizenship and urban unrest. After having recalled the history of the social housing movement ; in order to show that the recent proclamation giving the right to housing should be viewed as the culmination of a series of policies and social movements, a close examination of different housing projects and initiatives aimed at supplying suitable housing in the Rennes area was carried out. An examination of the spatial distribution of population using comparative and multi-variate analysis was undertaken. In particular an attempt was made to test different tools for the apprehension of the residential structure of a city and the characterisation of the phenomenon of urban poverty. A detailed examination of the different social and urban development policies implemented throughout the nineteen-eighties was carried out in order to characterise the different interventions of different agents playing a role in the creation, renovation and management of social housing stock. Lastly, a study of the socio-residential histories of individuals and families suffering from poverty has highlighted the wide variety and evolving nature of their situations as well as the unpredictable effects of social integration policies

Cette thèse a pour objectif de déterminer le devenir des populations marginales d’arbres boréo-montagnards dans le contexte des changements climatiques. La réponse dendroclimatique et la structure génétique des espèces sont analysées conjointement sur des gradients incluant les zones de distributions continues et marginales. Les deux modèles biologiques choisis sont le thuya occidental en limite nordique (forêt boréale canadienne) et le pin cembro en limite occidentale (Alpes). Les hypothèses suivantes ont été testées : le réchauffement climatique au cours du XXe siècle a entrainé une augmentation de croissance ; la variabilité de croissance est reliée à la structure génétique aux niveaux intra- et inter-populationnels. Une baisse de croissance du thuya a été observée après 1980 en zone marginale, qui serait liée à une limitation par la sécheresse. Pour les deux espèces, les relations climat-croissance étaient essentiellement modulées par le volume des précipitations, mais également par des variables édaphiques et par la taille des arbres. L’existence d’un lien significatif entre la structure génétique et certaines variables climatiques laisse néanmoins espérer un potentiel d'adaptation génétique, dont l’ampleur dépendra de la diversité génétique disponible pour la sélection naturelle. Par ailleurs, le synchronisme de croissance entre les arbres était à la fois influencé par la diversité génétique intra-populationnelle et par le volume des précipitations. En conclusion, il apparaît très difficile de distinguer les effets du climat et de la génétique sur la croissance des arbres étudiés
This thesis aims to assess the fate of marginal populations, in the context of climate change, for boreo-mountain tree species. The dendroclimatic response and the genetic structure of the species are jointly analyzed on gradients including both the continuous and the marginal distribution zones. Two biological models have been chosen for this research, white cedar at its northern limit (boreal forest) and stone pine at its western limit (temperate mountain forest). The following hypotheses were tested: global warming during the twentieth century has led to increased growth; growth variability is related to the genetic structure at the intra- and inter-population levels. A decline in cedar growth was observed after 1980 in marginal zone, which could be linked to drought constraints on growth. For both species, climate-growth relationships were essentially modulated by the amount of precipitation, but also by soil and tree-size variables. The existence of a significant link between genetic structure and some climatic variables still leaves some hope for a genetic adaptation potential, which magnitude will depend on the genetic diversity available for natural selection. The growth synchronicity between the trees was both influenced by the intra-population genetic diversity and the amount of precipitation. In conclusion, it is very difficult to disentangle the effects of climate and genetics on the growth of the studied trees

Le changement climatique affecte déjà les écosystèmes forestiers sur tous les continents, comme en témoignent la migration des espèces vers le nord et vers les plus hautes altitudes et l'augmentation du dépérissement des forêts en réponse, non seulement à des conditions climatiques plus rigoureuses, mais aussi à des épidémies de ravageurs et de maladies résultant d'événements climatiques sans précédent ainsi que de l'intensification des activités humaines. Ces phénomènes ont des conséquences négatives sur le fonctionnement des écosystèmes forestiers et la persistance des espèces et des populations, car ils menacent la disponibilité des ressources, perturbent la dynamique des populations et remettent en question les limites physiologiques et la résistance aux agents pathogènes. L'avenir des populations d'arbres de forêts naturelles face au changement climatique, compte tenu de leur nature sessile et de leur long temps de génération, est donc préoccupant, que ce soit en termes d'extinction, de capacité à migrer ou à s'adapter par le biais de changements génétiques. Du point de vue de la conservation, nous devons comprendre dans quelle mesure les arbres forestiers seront capables de survivre face au changement climatique actuel et futur. L'énorme quantité de données génomiques disponibles grâce aux outils de séquençage de nouvelle génération révolutionne notre compréhension de la base génétique de l'adaptation. À son tour, elle accélère le développement de nouvelles méthodes statistiques qui peuvent prédire la vulnérabilité génomique des arbres forestiers au changement climatique dans l'espace et dans le temps, et déterminer le potentiel de maladaptation génétique dans des conditions climatiques changeantes. Dans cette thèse de doctorat, j'ai utilisé le pin maritime (Pinus pinaster Ait.), un conifère à longue durée de vie originaire de la partie occidentale du bassin méditerranéen, comme étude de cas pour démêler les schémas spatiaux de la variation génétique à l'échelle de l'aire de répartition et à l'échelle régionale en fonction de différents gradients, anticiper les réponses des populations au changement climatique et donner un aperçu des tendances actuelles en matière de sélection naturelle. Le premier chapitre vise à comprendre comment, à l'échelle de l'aire de répartition de l'espèce, la variation génétique, l'adaptabilité et le potentiel d'inadaptation à court terme aux conditions climatiques futures sont distribués du coeur de l'aire de répartition vers les marges géographiques et climatiques. Le deuxième chapitre examine les 2 schémas spatiaux de la sélection naturelle contemporaine en analysant les changements phénotypiques en réponse aux pressions sélectives actuelles, et donne un aperçu des tendances actuelles de l'adaptation locale au changement climatique pour le pin maritime à l'état sauvage. Le troisième chapitre vise à identifier les schémas spatiaux de variation génétique du pin maritime dans l'île de Corse, caractérisée par des particularités spécifiques et constituant des ressources génétiques précieuses pour l'espèce, et à analyser leurs capacités d'adaptation actuelles et futures au changement climatique. Dans l'ensemble, cette thèse de doctorat étudie les facteurs sous-jacents et le potentiel des réponses adaptatives du pin maritime aux conditions environnementales changeantes à différentes échelles spatiales et temporelles, contribuant ainsi au développement d'un cadre intégratif essentiel pour anticiper les réponses des populations au changement climatique, sur la base duquel des prédictions solides pour les stratégies de conservation et de gestion peuvent être développées
Climate change is already affecting forest ecosystems on all continents, as evidenced by the northward and upward migration of species and the increase of forest dieback in response to not only harsher climate conditions but also to pest and disease epidemics resulting from unprecedented climatic events as well as the intensification of human activities. These phenomena have negative consequences for the functioning of forest ecosystems and the persistence of species and populations, as they threaten the availability of resources, disrupt population dynamics and call into question physiological limits and resistance to pathogens. The future of natural forest tree populations in the face of climate change, given their sessile nature and long generation times, is therefore worrying, whether in terms of extinction, ability to migrate or adapt through genetic change. From a conservation point of view, we need to understand the extent to which forest trees will be able to survive in the face of current and future climate change. The huge amount of genomic data available from next-generation sequencing tools is revolutionising our understanding of the genetic basis of adaptation. In turn, it is accelerating the development of new statistical methods that can predict the genomic vulnerability of forest trees to climate change in space and time, and determine the potential for genetic maladaptation under changing climatic conditions. In this PhD thesis, I used maritime pine (Pinus pinaster Ait.), a long-lived conifer native to the western part of the Mediterranean basin, as a case study to unravel the spatial patterns of genetic variation at the range-wide and regional scales function of different gradients, anticipate population responses to climate change and provide insight into current trends in natural selection. The first chapter aims to understand how, at the scale of the species range, genetic variation, adaptability and the potential for short-term maladaptation to future climatic conditions are distributed from the range core towards the geographical and climatic margins. The second chapter examines the spatial patterns of contemporary natural selection by analysing phenotypic changes in response to current selective pressures, and provides an overview of current trends in local adaptation to climate change for maritime pine in the wild. The third chapter aims to identify the spatial patterns of genetic variation of maritime pine in the Corsica Island, characterized by specific features and constituting valuable genetic resources for the species, and to analyse their current 4 and future adaptive capacities to climate change. Overall, this PhD thesis studies the underlying drivers and potential of maritime pine adaptive responses to changing environmental conditions at different spatial and temporal scales, thus contributing to the development of an integrative framework essential for anticipating population responses to climate change, on the basis of which robust predictions for conservation and management strategies can be developed

This study's purpose is to investigate the expansion of social control efforts in American elementary and secondary school settings, particularly the use of zero-tolerance policies. These policies entail automatic punishments, such as suspensions, expulsions, and referrals to the juvenile and criminal justice systems for a host of school-based infractions. The widespread implementation of zero-tolerance policies and the application of harsh, exclusionary sanctions have intensified over the past decade. Numerous studies have documented this rise; however, there has been little effort to explore the explanation of the expansion of school-based social controls. A potential explanation is found in the application of political economic theories in relation to the increased use and evolving nature of social control in the neoliberal era of capitalism. As such, the current study employs a new theoretical approach, which utilizes neoliberal theory combined with theoretical components from existing metanarratives in the literature. By using this new approach in regard to school-based social control, the connection between the expansion of social control of the working class and marginal populations in the criminal justice process, and the retraction of the social safety nets that characterized neoliberal capitalism is extended to the explanation of trends in the social control of school-based infractions. This investigation incorporates a qualitative, empirical exploration of how these school criminalization efforts have been implemented and legitimized by the state, specifically through the authority of the courts. By engaging in textual analysis, the jurisprudential intent that informs both the relevant state appellate and Supreme Court decisions was subjected to legal exegeses to determine how and if the judicial system legitimizes the practice of zero tolerance in schools, which are consistent with neoliberal ideals. In addition, a quantitative component, to this overall study, examined nationally representative School Survey on Crime and Safety (SSOCS) data across three academic years to determine if school security measures and disciplinary actions were increasingly applied to marginal populations in elementary and secondary schools over time. Results from the qualitative inquiry revealed that in the overwhelming majority of court cases evaluated, the courts decided in a fashion that reinforces zero-tolerance policies as legitimate neoliberal social controls in schools. Several theoretically relevant themes emerged from the jurisprudential intent, which are transferable for further theory development and future research. Quantitative findings reveal that, over time, the total disciplinary actions and removals from school without continued educational services are disproportionately applied to schools with the highest percentages of minority students and students who reside in high-crime areas compared to schools with the lowest percentages of minority students and students who reside in high-crime areas. Conversely, the results also reveal that the average use of school security measures (e.g., metal detectors, access controls, security guards, etc.) are more likely to be used in schools with the lowest percentages of minority students than schools with the highest percentages of minorities over time. These results are discussed in detail, and recommendations for changes in school policies and practices are offered, while being mindful of evidence-based best practices that may serve as viable alternatives to the zero-tolerance policies currently being used. Avenues for future research and theory development are also outlined.

Insects are ectotherms and have limited ability to regulate body temperature above or below ambient and are consequently greatly affected by temperature. The aphid \(Myzus\) \(persicae\) has an extensive distribution throughout Europe from Scandinavia to Southern Spain, representing three distinct climatic regions: sub-Arctic, temperate and Mediterranean. The aphid also has genetically distinct clones within its holocyclic (sexual) and anholocyclic (asexual) life cycles. This raises the possibility that aphids are regionally-adapted to distinct climatic zones along the latitudinal cline of its European distribution. Genetically distinct clones of \(M. persicae\) were collected from Sweden, UK and Spain. Indices of temperature tolerance (upper and lower lethal temperature50, coma temperatures and mobility thresholds) were determined for each aphid clone at different rearing temperatures. Acclimation at 10°C for one generation increased cold tolerance by depressing lower lethal, chill movement and chill coma temperatures when compared to 20°C and 25°C and further enabled mobility to be maintained to lower temperatures. Acclimation at 25°C for one generation increased heat tolerance by raising upper lethal, heat movement and heat coma temperatures when compared to 10°C and 20°C. Acclimation at 10°C also acted to raise upper lethal temperatures, indicating that the physiological processes conferring heat tolerance are induced at both high and low temperatures. Data did not support intergenerational acclimation to higher or lower temperatures. Lower thermal limits were more plastic than upper limits, enabling tolerance ranges to be increased following acclimation at 10°C, but reduced on acclimation at 25°C. Rates of change varied between clones, suggesting that certain clones could be more affected by climate change. A relationship between thermal tolerance range and latitude was not supported by data on thermal traits investigated with the exception of heat coma temperature. This suggests that clonal mixing across Europe is extensive and prevents local adaptation, although long term populations could persist in the Mediterranean allowing increased heat tolerance. Clonal type, as identified by microsatellite analysis, did show a relationship with thermal tolerance, suggesting that clonal types could respond independently to climate change, affecting relative proportions of clones within populations.

L'evaluation anthropometrique (poids, taille) d'un echantillon de 1137 enfants francais et immigres ages de six ans et frequentant cinq centres de pmi situes a paris montre que les retards staturaux sont plus frequents que les retards ponderaux. Ces retards sont de types marginaux et ont les prevalences les plus elevees chez les asiatiques du sud-est, les europeens non francais et les francais. Nous avons etudie les relations entre ces retards marginaux de croissance et certains parametres biochimiques. Les resultats montrent que les retards marginaux de poids chez ces enfants s'accompagnent d'une diminution des taux seriques de l'albumine, la transthyretine et des taux plasmatiques du zinc et ceci en comparaison avec une population d'enfants temoins de meme age, meme sexe et meme origine ethnique ayant une anthropometrie normale. Dans le dernier volet de ce travail, nous avons montre par une etude en double aveugle et controlee, une amelioration de la croissance staturo-ponderale chez des nourrissons en allaitement maternel prolonge recevant 5 milligrammesde sulfate de zinc par jour pendant une duree de 3 mois par rapport a ceux recevant un placebo

Plymouth Sound is an area of shallow marine to marginal marine sea approximately 10km² in size. It is situated on the South coast of England and partially restricted from the open ocean by the Breakwater. Its shallow marine waters are diluted by the outflow from two significant rivers; the Tamar and the Plym. All of these factors combined with the partial restriction of the Breakwater and open channels adjacent the Breakwater have created many different sub-environments within this small region. Very low energy to very high energy conditions are present, which range from normal marine, slightly hyposaline to moderately hyposaline. These varied sub-environments reflect many distinct foraminiferal assemblages, both living and dead. The live foraminiferal assemblages show great variation throughout the year in terms of abundance, diversity and number and style of reproductive events. The dead assemblage is relatively stable throughout the year. The assemblages from the different sub-environments reflect varying degrees of post-mortem alteration. A detailed study of the foraminiferal fauna reveals a complex interplay between energy conditions, sediment type, temperature and salinity which are reflected in the foraminiferal morphology, size and abundance. This is further complicated in the dead assemblages by post-mortem processes. The live assemblages were dominated by Ammonia beccarii batavus (Linne) which reached a maximum abundance of 1200 individuals per 100 cm³ and Elphidium crispum (Linne) which reached a maximum of 450 individuals per 100 cm³, other species were locally important such as Brizalina pseudopunctata (Hoglund) in the muds of the Breakwater (Location 9), which reached a maximum of 1600 individuals per 100 cm³. Production of species was very variable but production was highest during April/May, July and September/October. The dead assemblages are dominated by Cibicides lobatulus (Walker and Jacob), an exotic species, which testifies to considerable post-mortem transport. This species accounts for up to 60% of some assemblages. Ammonia beccarii batavus which accounts for up to 50% of some assemblages and Elphidium crispum which accounts for up to 30% of some assemblages. The vertical distribution of foraminifera within the various sedimentary facies and sub-environments was determined by the retrieval of nine sediment cores from six different facies over two years. The cores revealed that the greatest abundance of live foraminifera occurred in the uppermost centimeter/s of the sediment, particularly within muddy sediments. Cores for isotopic analysis were collected from three areas of the Sound and used to determined the sediment accumulation rate and date sediments down to approximately 50 centimeters. Sedimentation has been dynamic and discontinuous. Sediment accumulation rates range from 0.19 cm/per year to 0.48 cm/per year. In addition to the main foraminiferal study of the Sound the previously unstudied Plym Estuary was sampled. This revealed a typical low diversity calcareous fauna composed of Haynesina germanica (Ehrenberg) and Elphidium williamsoni Haynes which attained very high abundances of 4000 individuals per cm³. This study is the most recent of several spanning almost an entire century. Although the data from previous studies are limited, comparison of these previous studies with the present study indicate little change of foraminiferal species in recent time but potentially large changes, particularly in recent years, of foraminiferal abundance and biomass within the Sound.

Marginal zinc deficiency (MZD) exists in children of industrialized societies and can impair growth and development. Presently there are no data available on its global prevalence. It is believed that MZD is one of the most common hidden deficiencies throughout the world. This is partly because of the lack of sensitivity and specificity of serum zinc, the most commonly used biomarker of zinc status, to detect MZD. This deficiency in children is always accompanied by a decrease in hair zinc. Although in research settings hair zinc is a recognized biomarker of MZD in children, health practitioners do not presently use it. These cross-sectional studies were designed to examine the hair zinc status of preschoolers in Vancouver. They also aimed at exploring some dietary and non-dietary factors associated with hair zinc status in an attempt to construct and validate a screening tool for detection of MZD. Our first study indicated a mean hair zinc of 75��30 ��g/g, with 46% below the cutoff (<70��g/g) for a group (n=87) of low-income preschoolers (Chapter II). Among these children we observed negative associations between the hair zinc and consumption of dairy (R�� =0.09, P=0 .01) and milk (R�� =0.08, P=0.01), being described as "often sick" (R�� =0.55, P=0 .00) and "eating unhealthy" (R�� =0.16 P=0.00), and prolonged breastfeeding (R�� =0.11, P=0.01). Our citywide survey (n=719) indicated a mean hair zinc of 116��43 ��g/g with 17% below the cutoff (Chapter III). Logistic regression analysis indicated sex, age, maternal education, the number of adults at home, consumption frequency of milk, "scores of activity level", "being described as frequently sick" and "taking supplements containing iron" as the significant predictors of hair zinc status. However, the final model had 16% sensitivity while having 98 .3% specificity, indicating its lack of usefulness as a screening tool. Our study provides important information on the hair zinc status of Vancouver preschoolers. Although we did not accomplish our primary goal of constructing and validating a screening tool, we did identify some factors in children and their environment associated with hair zinc, which may help in better understanding of hair zinc as a biomarker of MZD.

Submitted by LUAN ALBERTO ODORIZZI DOS SANTOS null (luanodorizzi1@hotmail.com) on 2017-06-21T02:16:39Z No. of bitstreams: 1 TESE_LUAN_ALBERTO_ODORIZZI_DOS_SANTOS.pdf: 1320242 bytes, checksum: f90ac4fa9e096f32cb4444a87944e21f (MD5)
Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-06-21T14:31:07Z (GMT) No. of bitstreams: 1 santos_lao_dr_jabo.pdf: 1320242 bytes, checksum: f90ac4fa9e096f32cb4444a87944e21f (MD5)
Made available in DSpace on 2017-06-21T14:31:07Z (GMT). No. of bitstreams: 1 santos_lao_dr_jabo.pdf: 1320242 bytes, checksum: f90ac4fa9e096f32cb4444a87944e21f (MD5) Previous issue date: 2017-04-24
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
L'expansion des zones agricoles a conduit à la perte de biodiversité due à la réduction des habitats naturels et semi-naturels dans les paysages agricoles. Avec l'augmentation de la production agricole dans le monde, des techniques écologiquement rationnelles sont de plus en plus discutées qui permettent une gestion durable des habitats environnants. Les effets de ces habitats sur la population des insectes nuisibles et de leurs ennemis naturels sont encore mal connus. L'objectif de cette thèse était de comprendre les effets des environnements naturels et semi-naturels sur la population des insectes nuisibles et des ennemis naturels dans les régions tropicales (Brésil) et tempérées (France). Au Brésil (chapitre II), on a évalué l'effet de la distance des fragments sur la population de fourmis prédatrices et omnivores dans la canne à sucre. Les résultats montrent que la richesse en espèces diminue avec la distance des fragments forestiers et que la prédominance des espèces Dorymyrmex bruneus et Pheidole oxyops augmente. Des espèces de fourmis colonisant les champs de canne à sucre ont également été trouvées dans des fragments forestiers, ce qui suggère que ces derniers habitats sont des refuges pour les espèces de fourmis prédatrices pendant les périodes de perturbation comme la récolte de la canne à sucre ou le travail du sol. Cela a été confirmé par des différences plus fortes dans les communautés de fourmis après la récolte de la canne à sucre (saison sèche) que quatre mois plus tard / (saison des pluies) quand l'absence de perturbation a permis la re-lonosiation par les fourmis. Il y avait aussi une différence dans la richesse des espèces de fourmis entre les différents types de fragments (vallées fluviales et plaines). En France, on a évalué l'effet des bandes de fleurs sauvages, de la végétation spontanée et des bandes d'herbe sur la communauté des ennemis naturels et la régulation du puceron de la pomme rosâtre Dysaphis plantaginaea (chapitre III). En ce qui concerne les principaux ennemis naturels, nos résultats ont montré une densité plus élevée de hoverflies par rapport à d'autres types de bande, mais aucune différence pour les coccinelles (coccinelidae). Cependant, aucune différence de densité naturelle de l'ennemi n'a été observée à l'intérieur des vergers. Le nombre de pucerons était plus élevé près des marges, ce qui suggère que la colonisation à partir des bandes marginales peut contrecarrer les effets régulateurs positifs des ennemis naturels. Les effets positifs de la végétation de la marge de bande sur la régulation des ravageurs de la pomme nécessitent un mouvement d'ennemis naturels dans le verger. Nous avons testé les mouvements des prédateurs généralistes en étiquetant les bandes de marge avec des protéines d'oeufs et nous avons vérifié si elles se nourrissaient d'insectes nuisibles en utilisant l'analyse de marqueurs génétiques des gènes de papillon (Cydia pomonella) à l'intérieur des prédateurs (chapitre IV). Les résultats ont montré que peu de personnes se déplaçaient des marges de champ dans le verger. Cependant, 25% des prédateurs capturés se nourrissaient de C. pomonella indiquant encore un haut niveau de régulation naturelle. En conclusion, le mouvement limité des prédateurs à partir des bandes de marges dans les vergers peut expliquer l'absence de différences entre les traitements de bandes dans la régulation des ravageurs du verger (pucerons). Les habitats naturels et semi-naturels peuvent contribuer à la lutte contre les ravageurs en marge des cultures, mais dans les vergers de pommiers cet effet a fortement diminué avec la distance.
A expansão das áreas agrícolas levou à perda de biodiversidade devido à redução dos habitats naturais e semi-naturais nas paisagens agrícolas. Com o aumento da produção agrícola no mundo, são cada vez mais discutidas técnicas ambientais que permitem uma gestão sustentável dos habitats do entorno. Os efeitos desses habitats sobre a população de insetos-pragas e seus inimigos naturais ainda são mal compreendidos. O objetivo desta tese foi compreender os efeitos dos ambientes naturais e semi-naturais na população de insetos-pragas e inimigos naturais nas regiões tropicais (Brasil) e temperadas (França). No Brasil (Capítulo II) foi avaliado o efeito da distância de fragmentos sobre a população de formigas predadoras e omnívoras em cana-de-açúcar. Os resultados mostraram que a riqueza de espécies diminui com a distância dos fragmentos florestais e que a dominância das espécies Dorymyrmex bruneus e Pheidole oxyops aumenta. As espécies de formigas que colonizam áreas de cana-de-açúcar também foram encontradas em fragmentos de florestas, sugerindo que estes últimos são abrigos para espécies de formigas predatórias durante períodos de perturbação como colheita de cana-de-açúcar ou preparo do solo. Isto foi confirmado por diferenças mais fortes nas comunidades de formigas após a colheita da cana (estação seca) do que quatro meses depois (estação chuvosa) quando a ausência de perturbação permitiu recolonização por formigas. Houve também uma diferença na riqueza de espécies de formigas entre diferentes tipos de fragmentos (vales de rios e planícies). Na França, foi avaliado o efeito de faixas de flores silvestres, vegetação espontânea e gramíneas na comunidade de inimigos naturais e a regulação do pulgão cinza Dysaphis plantaginaea (Capítulo III). No que diz respeito aos principais inimigos naturais, os nossos resultados mostraram uma maior densidade de sirfideos nas faixas de flores em comparação com outros tipos de faixas, mas nenhuma diferença para joaninha (Coccinelidae). Não foram observadas diferenças nas densidades de inimigos naturais dentro dos pomares. O número de afídeos foi maior perto das margens, sugerindo que a colonização das faixas nas margens pode neutralizar os efeitos reguladores positivos dos inimigos naturais. Os efeitos positivos da vegetação nas faixas da margem na regulação de pragas da maçã requerem um movimento de inimigos naturais no pomar. Nós testamos os movimentos de predadores generalistas marcando as faixas das margens com proteína de ovo e verificamos se eles se alimentavam de insetos pragas usando a análise de marcadores moleculares de genes de mariposas (Cydia pomonella) nos predadores (capítulo IV). Os resultados mostraram que poucos indivíduos se movimentaram das margens do campo para o pomar. No entanto, 25% dos predadores capturados alimentados com C. pomonella ainda indicam um alto nível de regulação natural. Em conclusão, o movimento limitado de predadores das faixas de plantas nas margens em pomares pode explicar a ausência de diferenças entre os tratamentos na regulação de pragas do pomar (pulgões). Habitats naturais e semi-naturais podem contribuir para o controle de pragas nas margens das culturas, mas em pomares de maçã este efeito diminuiu fortemente com a distância.
The expansion of agricultural areas has led to the loss of biodiversity due to the reduction of natural and semi-natural habitats in agricultural landscapes. With the increase of agricultural production in the world, environmentally sound techniques are increasingly discussed that allow a sustainable management of surrounding habitats. The effects of these habitats on the population of insect pests and their natural enemies are still poorly understood. The objective of this thesis was to understand the effects of natural and semi-natural environments on the population of insect pests and natural enemies in tropical (Brazil) and temperate (France) regions. In Brazil (Chapter II) the effect of the distance of fragments on the population of predatory and omnivorous ants in sugarcane was evaluated. The results showed that the species richness decrease with distance from forest fragments and that the dominance of the species Dorymyrmex bruneus and Pheidole oxyops increase. Ant species colonizing sugarcane fields were also found in forest fragments suggesting that the latter habitats are refuges for predatory ant species during periods of disturbance such as sugarcane harvest or soil tillage. This was confirmed by stronger differences in ant communities after sugarcane harvest (dry season) than four months later (rainy season) when absence of disturbance allowed re-colonosiation by ants. There was also a difference in the richness of ant species between different fragment types (river valleys and plateaus). In France, the effect of wildflower strips, spontaneous vegetation and grass strips on the community of natural enemies and the regulation of the rosy apple aphid Dysaphis plantaginaea (Chapter III) were evaluated. Concerning major natural enemies, our results showed a higher density of hoverflies in wild flower strips compared with other strip types but no differences for ladybirds (coccinelidae). However, no differences in natural enemy densities were observed inside orchards. Aphid number was higher close to the margins suggesting that colonization from margin strips may counteract positive regulatory effects of natural enemies. Positive effects of strip margin vegetation on regulation of apple pests require a movement of natural enemies into the orchard. We tested the movements of generalist predators by labelling margin strips with egg protein and we checked whether they fed on pest insects using specific genetic marker of the codling moth (Cydia pomonella) (chapter IV). The results showed that few individuals were moving from the field margins into the orchard. However, 25% of the captured predators fed on C. pomonella still indicating a high level of natural regulation. In conclusion, the limited movement of predators from margin strips into orchards may explain the absence of differences between strip treatments in orchard pest regulation (aphids). Natural and semi-natural habitats can contribute to pest control at the margins of crops, but in apple orchards this effect strongly decreased with distance.

Orientador: Odair Aparecido Fernandes
Coorientador: Armin Bischoff
Banca: Pierre Franck
Banca: Daniel Junior de Andrade
Banca: Olivier Blight
Banca: Raphael de Campos Castilho
Abstract: The expansion of agricultural areas has led to the loss of biodiversity due to the reduction of natural and semi-natural habitats in agricultural landscapes. With the increase of agricultural production in the world, environmentally sound techniques are increasingly discussed that allow a sustainable management of surrounding habitats. The effects of these habitats on the population of insect pests and their natural enemies are still poorly understood. The objective of this thesis was to understand the effects of natural and semi-natural environments on the population of insect pests and natural enemies in tropical (Brazil) and temperate (France) regions. In Brazil (Chapter II) the effect of the distance of fragments on the population of predatory and omnivorous ants in sugarcane was evaluated. The results showed that the species richness decrease with distance from forest fragments and that the dominance of the species Dorymyrmex bruneus and Pheidole oxyops increase. Ant species colonizing sugarcane fields were also found in forest fragments suggesting that the latter habitats are refuges for predatory ant species during periods of disturbance such as sugarcane harvest or soil tillage. This was confirmed by stronger differences in ant communities after sugarcane harvest (dry season) than four months later (rainy season) when absence of disturbance allowed re-colonosiation by ants. There was also a difference in the richness of ant species between different fragment types (ri... (Complete abstract click electronic access below)
Résumé: L'expansion des zones agricoles a conduit à la perte de biodiversité due à la réduction des habitats naturels et semi-naturels dans les paysages agricoles. Avec l'augmentation de la production agricole dans le monde, des techniques écologiquement rationnelles sont de plus en plus discutées qui permettent une gestion durable des habitats environnants. Les effets de ces habitats sur la population des insectes nuisibles et de leurs ennemis naturels sont encore mal connus. L'objectif de cette thèse était de comprendre les effets des environnements naturels et semi-naturels sur la population des insectes nuisibles et des ennemis naturels dans les régions tropicales (Brésil) et tempérées (France). Au Brésil (chapitre II), on a évalué l'effet de la distance des fragments sur la population de fourmis prédatrices et omnivores dans la canne à sucre. Les résultats montrent que la richesse en espèces diminue avec la distance des fragments forestiers et que la prédominance des espèces Dorymyrmex bruneus et Pheidole oxyops augmente. Des espèces de fourmis colonisant les champs de canne à sucre ont également été trouvées dans des fragments forestiers, ce qui suggère que ces derniers habitats sont des refuges pour les espèces de fourmis prédatrices pendant les périodes de perturbation comme la récolte de la canne à sucre ou le travail du sol. Cela a été confirmé par des différences plus fortes dans les communautés de fourmis après la récolte de la canne à sucre (saison sèche) que quatre mois... (Résumé complet accès életronique ci-dessous)
Resumo: A expansão das áreas agrícolas levou à perda de biodiversidade devido à redução dos habitats naturais e semi-naturais nas paisagens agrícolas. Com o aumento da produção agrícola no mundo, são cada vez mais discutidas técnicas ambientais que permitem uma gestão sustentável dos habitats do entorno. Os efeitos desses habitats sobre a população de insetos-pragas e seus inimigos naturais ainda são mal compreendidos. O objetivo desta tese foi compreender os efeitos dos ambientes naturais e semi-naturais na população de insetos-pragas e inimigos naturais nas regiões tropicais (Brasil) e temperadas (França). No Brasil (Capítulo II) foi avaliado o efeito da distância de fragmentos sobre a população de formigas predadoras e omnívoras em cana-de-açúcar. Os resultados mostraram que a riqueza de espécies diminui com a distância dos fragmentos florestais e que a dominância das espécies Dorymyrmex bruneus e Pheidole oxyops aumenta. As espécies de formigas que colonizam áreas de cana-de-açúcar também foram encontradas em fragmentos de florestas, sugerindo que estes últimos são abrigos para espécies de formigas predatórias durante períodos de perturbação como colheita de cana-de-açúcar ou preparo do solo. Isto foi confirmado por diferenças mais fortes nas comunidades de formigas após a colheita da cana (estação seca) do que quatro meses depois (estação chuvosa) quando a ausência de perturbação permitiu recolonização por formigas. Houve também uma diferença na riqueza de espécies de formigas e... (Resumo completo, clicar acesso eletrônico abaixo)
Doutor

The scope of this thesis was to identify, describe and quantify important life-history traits for the pseudoannual aquatic plant Ranunculus lingua in different ecological settings, by comparing populations from geographically marginal vs. central habitats. Results from a four-year field study showed that abiotic factors (water-level fluctuations and associated processes) tended to have a greater influence in marginal populations, whereas biotic factors (competition, insect grazing and fungal infections) dominated in central populations. This was reflected in different depth distribution of ramet numbers and ramet sizes between the areas, and In different dynamic patterns, with a higher flux of ramets in marginal populations. In a reciprocal transplant experiment, marginal ramets produced more but smaller rhizomes, whereas central ramets produced Individually larger but fewer rhizomes, irrespective of transplant site. A possible selection for genotypes producing large rhizomes in the central habitat was supported by the fact that initially smaller ramets were more likely to be diseased by the fungal pathogen Peronospora gigantea and damaged by insect grazing. In the marginal population, where density-independent mortality factors tend to dominate, a high reproductive output, expressed in production of high numbers of rhizomes, was suggested to be a favoured life-history trait. In a glasshouse experiment, ramets from marginal and central populations were grown in low and high densities and under three contrasting nutrient levels. The allocation to sexual structures was generally very low, and did not incur any costs in terms of reduced rhizome production. Rhizome production showed strong positive allometrical relationships to mother ramet size. Increasing mother ramet size resulted in a larger increase in rhizome numbers for the marginal than for the central population, whereas the increase in mean rhizome mass was more pronounced for the centred population. Both populations showed similar reductions in rhizome production in response to increased density and lowered nutrient levels, which could not be explained by size-dependent effects adone. The dispersal, dynamics and distribution of R. lingua were studied in a marginal river population in northern Sweden, where the only means of dispersal is by vegetative diaspores, i.e. floating rhizome fragments. Stranding occurred mainly in river curves and at obstacles, and the distribution of established stands was also highly correlated with these features. Relative changes in ramet numbers were correlated with water-level fluctuations during the present and previous growing seasons, with winter low-water, and with duration of spring-flood. The predictability of change was high within but low between stands. It was concluded that the patterns and mechanisms of dispersal are fundamental for local distribution patterns as well as variation in regional abundance in R. lingua

Diss. (sammanfattning) Umeå : Umeå universitet, 1992, härtill 4 uppsatser

digitalisering@umu

Made available in DSpace on 2015-03-03T11:52:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-27Bitstream added on 2015-03-03T12:06:49Z : No. of bitstreams: 1 000807424_20161216.pdf: 2750566 bytes, checksum: 7abf8b6951850fddd07d259698cbd65f (MD5) Bitstreams deleted on 2016-12-16T09:54:40Z: 000807424_20161216.pdf,. Added 1 bitstream(s) on 2016-12-16T09:55:20Z : No. of bitstreams: 1 000807424.pdf: 4968033 bytes, checksum: e92dcddf8858995cc173cd998f274813 (MD5)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Em ambientes aquáticos controlados por barragens, a elevada estabilidade hídrica favorece a proliferação de macrófitas, sendo para seu controle utilizado um manejo por alterações no nível da água. Porém não existem estudos que avaliem o efeito dessa técnica, que gera condições extremas de seca e inundação sobre a fauna de invertebrados fitófilos. O presente trabalho foi realizado durante alterações operacionais do nível da água para controle de macrófitas submersas no reservatório de Salto Grande (SP/PR). O objetivo foi avaliar o efeito dessas alterações sobre a diversidade de invertebrados associados à macrófita Egeria na lagoa Pedra Branca, conectada ao Rio Paranapanema e sob a influência do reservatório. As coletas foram realizadas ao longo de um transecto longitudinal da lagoa, antes do manejo ser iniciado (controle), no 1º, 7º e 11º dias após o rebaixamento (PR), quando a lagoa se desconecta do rio, e 49 dias após o enchimento do reservatório (PE). A hipótese do trabalho de menor diversidade após as alterações do nível da água do reservatório (seca e cheia induzidas) foi avaliada ao nível de toda a fauna e para os táxons de Chironomidae. As alterações do nível da água foram acompanhadas por alterações na estrutura da fauna fitófila, com variação temporal na densidade dos grupos, especialmente de Hexapoda, Mollusca e Protozoa. As mudanças ambientais relacionadas à contração (seca), e conseqüente concentração das macrófitas na área central da lagoa, e ampliação (cheia) das regiões limnética e litorânea geraram uma substituição de grupos dominantes (reduzindo a densidade de Chironomidae e aumentando a de Physa marmorata durante o PR), aumento na riqueza e maior diversidade e equitabilidade no PE. Os distúrbios causaram redução na densidade das três subfamílias de Chironomidae, principalmente de Chironominae, com maior riqueza e dominância em todas as datas ...

Orientador: Virgínia Sanches Uieda
Banca: Ana Lúcia Brandimarte
Banca: Marcelo Luiz Martins Pompêo
Banca: Alaíde Aparecida Fonseca Gessner
Banca: Marcos Gomes Nogueira
Resumo: Em ambientes aquáticos controlados por barragens, a elevada estabilidade hídrica favorece a proliferação de macrófitas, sendo para seu controle utilizado um manejo por alterações no nível da água. Porém não existem estudos que avaliem o efeito dessa técnica, que gera condições extremas de seca e inundação sobre a fauna de invertebrados fitófilos. O presente trabalho foi realizado durante alterações operacionais do nível da água para controle de macrófitas submersas no reservatório de Salto Grande (SP/PR). O objetivo foi avaliar o efeito dessas alterações sobre a diversidade de invertebrados associados à macrófita Egeria na lagoa Pedra Branca, conectada ao Rio Paranapanema e sob a influência do reservatório. As coletas foram realizadas ao longo de um transecto longitudinal da lagoa, antes do manejo ser iniciado (controle), no 1º, 7º e 11º dias após o rebaixamento (PR), quando a lagoa se desconecta do rio, e 49 dias após o enchimento do reservatório (PE). A hipótese do trabalho de menor diversidade após as alterações do nível da água do reservatório (seca e cheia induzidas) foi avaliada ao nível de toda a fauna e para os táxons de Chironomidae. As alterações do nível da água foram acompanhadas por alterações na estrutura da fauna fitófila, com variação temporal na densidade dos grupos, especialmente de Hexapoda, Mollusca e Protozoa. As mudanças ambientais relacionadas à contração (seca), e conseqüente concentração das macrófitas na área central da lagoa, e ampliação (cheia) das regiões limnética e litorânea geraram uma substituição de grupos dominantes (reduzindo a densidade de Chironomidae e aumentando a de Physa marmorata durante o PR), aumento na riqueza e maior diversidade e equitabilidade no PE. Os distúrbios causaram redução na densidade das três subfamílias de Chironomidae, principalmente de Chironominae, com maior riqueza e dominância em todas as datas ...
Abstract: Not available
Doutor

L'expansion des zones agricoles a conduit à la perte de biodiversité due à la réduction des habitats naturels et semi-naturels dans les paysages agricoles. Avec l'augmentation de la production agricole dans le monde, des techniques écologiquement rationnelles sont de plus en plus discutées qui permettent une gestion durable des habitats environnants. Les effets de ces habitats sur la population des insectes nuisibles et de leurs ennemis naturels sont encore mal connus. L'objectif de cette thèse était de comprendre les effets des environnements naturels et semi-naturels sur la population des insectes nuisibles et des ennemis naturels dans les régions tropicales (Brésil) et tempérées (France). Au Brésil (chapitre II), on a évalué l'effet de la distance des fragments sur la population de fourmis prédatrices et omnivores dans la canne à sucre. Les résultats montrent que la richesse en espèces diminue avec la distance des fragments forestiers et que la prédominance des espèces Dorymyrmex bruneus et Pheidole oxyops augmente. Des espèces de fourmis colonisant les champs de canne à sucre ont également été trouvées dans des fragments forestiers, ce qui suggère que ces derniers habitats sont des refuges pour les espèces de fourmis prédatrices pendant les périodes de perturbation comme la récolte de la canne à sucre ou le travail du sol. Cela a été confirmé par des différences plus fortes dans les communautés de fourmis après la récolte de la canne à sucre (saison sèche) que quatre mois plus tard / (saison des pluies) quand l'absence de perturbation a permis la re-lonosiation par les fourmis. Il y avait aussi une différence dans la richesse des espèces de fourmis entre les différents types de fragments (vallées fluviales et plaines). En France, on a évalué l'effet des bandes de fleurs sauvages, de la végétation spontanée et des bandes d'herbe sur la communauté des ennemis naturels et la régulation du puceron de la pomme rosâtre Dysaphis plantaginaea (chapitre III). En ce qui concerne les principaux ennemis naturels, nos résultats ont montré une densité plus élevée de hoverflies par rapport à d'autres types de bande, mais aucune différence pour les coccinelles (coccinelidae). Cependant, aucune différence de densité naturelle de l'ennemi n'a été observée à l'intérieur des vergers. Le nombre de pucerons était plus élevé près des marges, ce qui suggère que la colonisation à partir des bandes marginales peut contrecarrer les effets régulateurs positifs des ennemis naturels. Les effets positifs de la végétation de la marge de bande sur la régulation des ravageurs de la pomme nécessitent un mouvement d'ennemis naturels dans le verger. Nous avons testé les mouvements des prédateurs généralistes en étiquetant les bandes de marge avec des protéines d'oeufs et nous avons vérifié si elles se nourrissaient d'insectes nuisibles en utilisant l'analyse de marqueurs génétiques des gènes de papillon (Cydia pomonella) à l'intérieur des prédateurs (chapitre IV). Les résultats ont montré que peu de personnes se déplaçaient des marges de champ dans le verger. Cependant, 25% des prédateurs capturés se nourrissaient de C. pomonella indiquant encore un haut niveau de régulation naturelle. En conclusion, le mouvement limité des prédateurs à partir des bandes de marges dans les vergers peut expliquer l'absence de différences entre les traitements de bandes dans la régulation des ravageurs du verger (pucerons). Les habitats naturels et semi-naturels peuvent contribuer à la lutte contre les ravageurs en marge des cultures, mais dans les vergers de pommiers cet effet a fortement diminué avec la distance
The expansion of agricultural areas has led to the loss of biodiversity due to the reduction of natural and semi-natural habitats in agricultural landscapes. With the increase of agricultural production in the world, environmentally sound techniques are increasingly discussed that allow a sustainable management of surrounding habitats. The effects of these habitats on the population of insect pests and their natural enemies are still poorly understood. The objective of this thesis was to understand the effects of natural and semi-natural environments on the population of insect pests and natural enemies in tropical (Brazil) and temperate (France) regions. In Brazil (Chapter II) the effect of the distance of fragments on the population of predatory and omnivorous ants in sugarcane was evaluated. The results showed that the species richness decrease with distance from forest fragments and that the dominance of the species Dorymyrmex bruneus and Pheidole oxyops increase. Ant species colonizing sugarcane fields were also found in forest fragments suggesting that the latter habitats are shelters for predatory ant species during periods of disturbance such as sugarcane harvest or soil tillage. This was confirmed by stronger differences in ant communities after sugarcane harvest (dry season) than four months later /(rainy season) when absence of disturbance allowed re-colonization by ants. There was also a difference in the richness of ant species between different fragment types (river valleys and plateaus). In France, the effect of wildflower strips, spontaneous vegetation and grass strips on the community of natural enemies and the regulation of the rosy apple aphid Dysaphis plantaginaea (Chapter III) were evaluated. Concerning major natural enemies, our results showed a higher density of hoverflies compared with other strip types but no difference for ladybirds (coccinelidae). No differences in natural enemy densities were observed inside orchards. Aphid number was higher close to the margins suggesting that colonization from margin strips may counteract positive regulatory effects of natural enemies. Positive effects of strip margin vegetation on regulation of apple pests require a movement of natural enemies into the orchard. We tested the movements of generalist predators by labelling margin strips with egg protein and we checked whether they fed on pest insects using genetic marker analysis of codling (Cydia pomonella) moth genes inside predators (chapter IV). The results showed that few individuals were moving from the field margins into the orchard. However, 25% of the captured predators fed on C. pomonella still indicating a high level of natural regulation. In conclusion, the limited movement of predators from margin strips into orchards may explain the absence of differences between strip treatments in orchard pest regulation (aphids). Natural and semi-natural habitats can contribute to pest control at the margins of crops, but in apple orchards this effect strongly decreased with distance

After a brief respite in the mid to late 20th century, macro physiology has come to the fore in elucidating large scale ecological patterns and processes as physiological assumptions often form the backbone of many predictive theories associated with species distributions. Critically, macro physiological patterns are valuable in explaining physiological variation across multiple scales and provide insights into the effects of climate change on populations spanning a wide range of latitudes. This can assist in predicting possible distribution expansions, contractions or shifts in light of current climate change scenarios. From this perspective, investigating intra- and inter-specific physiological responses to environmental stress may contribute to better understanding and predicting the effects of climate change on geographical ranges. Further, investigating the physiological effects to environmental stresses across ontogenetic stages allows for the identification of weak links within the lifecycle of a species. Additionally, determining settlement characteristics along a latitudinal cline provides integrated indications of the sustainability of populations, highlighting vulnerable regions in terms of repopulation of viable habitats. In this context, the present study aimed at establishing how temperature, in a physiological context, may affect reproductive biology of two species of mangrove crab, Perisesarma guttatum and Uca urvillei at the centre (Kenya) and edge (South Africa) of their distributional range along the east coast of Africa and highlight possible consequences for range distributions. A third species, Neosarmatium africanum, only in South Africa, was included to provide additional interspecies comparisons. Furthermore, settlement characteristics of brachyuran populations at the centre and edge of their distributional range were considered in order to determine how settlement may contribute to population persistence. Physiological investigations at the centre and edge of distributional range and across ontogenetic stages (larvae, stage 2 and 4 embryos, non-gravid and gravid females) under the concept of oxygen and capacity limitation of thermal tolerance (OCLTT), revealed that, for both species, populations at the centre of their distribution (Kenya) were generally more robust to increasing temperatures and generally displayed greater physiological stability with increasing temperatures compared to their conspecifics in South Africa. Variability in physiological robustness between regions, did however, differ among ontogenetic stages and species but, overall, were evident throughout. Within and between regions, adaptation to oxygen extraction in both milieus (air or water) was displayed for present temperature conditions but aerial respiration largely alleviated increased thermal stress due to overcoming the limitations of reduced oxygen availability and diffusiveness in water for all bimodal ontogenetic stages. Brooding eggs proved to be a physiologically critical process with either heighted oxygen consumption for gravid females or collapse of physiological processes demonstrated by supressed oxygen consumption. The physiological cost of brooding eggs, referred to as maternal costs, was reflected in in both Perisesarma guttatum and Uca urvillei where, in most cases, maternal costs were negative. Again, aerial respiration was able to alleviated increased thermal stress, as shown by positive maternal costs indicating sustained maternal care, but this mechanism was species and regionally specific. Settlement patterns differed between the edge and centre of distribution of the species studied. This difference was predominantly driven by zonal preference within the mangal and/or effects of new and full moon (lunar phase). Overall, settlement dynamics were more widely variable in South Africa, both spatially and temporally, than in Kenya. Finally, empirical physiological data from ontogenetic stages present during the reproductive process (early and late stage embryos) and from non-gravid and gravid females were used in conjunction with data mined from the existing literature to parameterise an individual based model designed to simulate reproductive output at the centre and edge of distribution of Perisesarma guttatum. Physiological data indicate that, in terms of reproductive output across increasing temperatures, populations based at the centre of their distribution presently outperform their counterparts at the edge of the species’ distribution, but reproductive output stagnated as temperature rose. Edge of distribution populations consistently increased reproductive output with increasing temperatures to eventually outperform centre of distribution populations at higher simulated temperatures. Overall, results of the physiological and settlement studies suggest that with increased climate change there may be a contraction of distributional range of the study species from high latitudes to low latitudes, contrary to general poleward shifts/migrations seen in most species, with possible contractions of the entire ecosystem mirroring the disappearance of keystone mangrove macrofauna.

Introduction: The purpose of this study was to evaluate the changes in marginal ridge alignment occurring through normal growth and development from early childhood to late adulthood and to examine if any statistical variation exists between males and females. Methods: Dental casts of 38 subjects (15 females and 23 males) from the Iowa Growth Study were selected. The marginal ridge discrepancy was measured as the absolute value difference between adjacent marginal ridges of 20 interproximal contacts with both the ABO tool (data not shown) and a vertically mounted digital caliper. Upper and lower casts were tripoded to a level plane defined by the most posterior tooth and central point of the most erupted central incisor. A 15 subject calibration was used to measure inter-examiner reliability using the Cronbach’s Alpha and Kappa tests. The independent samples t test was used to examine the correlation of marginal ridge discrepancies between males and females. Results: Cronbach alpha (p ≤ .001) and Kappa test (p ≤ .01) show excellent inter-rater reliability. The independent sample t test showed no statistical significance, with minimal exception, in marginal ridge discrepancies between males and females matched for age (p > .05). Group 1 showed significantly higher number of marginal ridge discrepancies within ABO range of 0 – 0.5 mm of males and females compared to Group 2. Conclusion: Based on this study, no statistically significant differences were found in marginal ridge discrepancies between males and females. Also, the magnitude of marginal ridge discrepancies of erupting permanent teeth shows a decrease as an individual proceeds through growth and development and they remain relatively “level” during primary dentition.

Abstract Climate change causes range expansions, but neither the population parameters nor the ecological mechanisms behind range expansions are well known. I studied population dynamics and demography of the great tit (Parus major) in northern Finland, close to the northern range margin of the species’ distribution. I further examined winter conditions, such as temperature, as limiting factors on winter site fidelity and survival of human-fed great tits. Temporal variation in the population growth rate was large, but indicated an overall increasing population size, which fits the current large scale increase in the north. Importantly, the study population was a sink (or pseudo-sink) in almost all years because of low adult survival and low local recruitment. Immigration formed 39–43% of the annual population growth rate indicating that the population is demographically dependent on immigration. The demography differs most from other great tit populations in terms of adult survival which is lower than estimates from more southern Europe. This difference may reflect the impact of more difficult winters. Results from the wintering population support this line of reasoning. Within-winter movement was lower during mid-winter (January to February) and decreased during cold periods. This pattern is probably linked to energy saving and predator escaping strategies during these demanding periods when energy expenditure is high and birds have limited daylight hours to forage. Site fidelity was lower for juveniles than adults within a winter, but not between winters. In addition, survival showed strong links to winter weather. There was temporal variation within winters, particularly when the winter was colder than usual. Survival of juveniles showed a stronger response to cold temperatures. When mean daily minimum temperatures declined below –15 C° degrees, survival started to decline. Low winter temperatures thus provide one explanation for the lower annual adult survival and the sink nature of the population. The results suggest that great tits suffer from the cold conditions of the north: higher mortality increases turnover allowing for strong immigration. Great tits should benefit from warming winters caused by climate change
Tiivistelmä Väitöskirjassani tutkin talitiaisen (Parus major) populaatiodynamiikkaa, talviaikaista paikkauskollisuutta ja säilyvyyttä levinneisyysalueen pohjoisreunan läheisessä populaatiossa Oulussa. Aikuissäilyvyys oli vuosittain hieman alhaisempi kuin lajin ydinalueella Länsi-Euroopassa. Tutkimusalueella syntyneistä poikasista vain pieni osa jäi pesimään tutkimusalueelle, mikä heijastaa voimistunutta lähtömuuttoa huonolaatuiselta alueelta. Ajallinen vaihtelu populaation kasvukertoimessa oli suurta, mutta keskiarvo osoittaa nykyisen populaation kasvavan. Havaitsemani populaation kasvu ei selity kasvulla aikuissäilyvyydessä tai paikallisessa rekrytoinnissa. Oletan, että populaatio on ollut tulomuuton ylläpitämä nielu (tai valenielu) lähes kaikkina tutkimusvuosina. Niinpä populaatio on demografisesti ja geneettisesti riippuvainen ydinalueesta, josta tuleva geenivirta aiheuttaa ongelmia paikallisiin olosuhteisiin sopeutumisessa. Tutkin sekä talvensisäistä että talvien välistä paikkauskollisuutta suhteessa ikään, sukupuoleen, vuodenaikaan, lämpötilaan ja päivän pituuteen. Talvensisäinen liikkuvuus oli vähäisintä keskitalvella erityisesti kylmien jaksojen aikana. Tämä ilmiö on luultavasti yhteydessä energiansäästöön ja saalistajien välttelyyn näiden vaativien jaksojen aikana, jolloin energiankulutus on suurta ja valoisa ruokailuaika on lyhyt. Nuorten talvensisäinen paikkauskollisuus oli huonompi kuin aikuisten, mutta sukupuolten välillä tässä ei ollut eroa. Sen sijaan talvien välisessä paikkauskollisuudessa ei ollut ryhmien välisiä eroja, mikä viittaa paikkauskollisuudesta olevan yhtäläiset hyödyt kaikille. Nuoret luultavasti keräävät tietoa resursseista ensimmäisenä talvenaan ja täten hankkivat samat edut kuin aikuiset palatessaan alueelle seuraavana talvena. Tutkin, onko talvella lintujen ruokintapaikkoja hyödyntävien talitiaisten säilyvyydessä ympäristötekijöistä, kuten lämpötilasta, johtuvaa vaihtelua. Talvisäilyvyys vaihteli paljon etenkin tavallista kylmempänä talvena. Nuoret kärsivät eniten kylmistä lämpötiloista. Kun keskilämpötila laski –15 C°:seen tai sen alapuolelle, säilyvyys alkoi heikentyä. Verrattuna kylmään talveen säilyvyys oli 1,5 kertaa todennäköisempää lauhan talven aikana. Talitiaiset näyttävät kärsivän pohjoisen kylmistä olosuhteista: korkea kuolleisuus lisää vaihtuvuutta ja geenivirtaa, kun alueelle kohdistuu voimakasta tulomuuttoa

The future climate change represents the biggest challenge for plant and animal species. The scenarios forecasted by the IPCC predict a global increase in temperatures and regional changes in rainfall during this century. Therefore, studying the relationship between climate and several traits of species is crucial in our understanding of the effects that future changes may have on plants. Species growing along a wide environmental gradient are a suitable study model to verify the relationship between intraspecific variability and both current and future climate. The aim of my PhD project is to analyse the relationship between environmental variability and variation in morphological traits, germination capacity and genetic structure of Lilium pomponium, using a multidisciplinary approach. The results of this study may enhance our understanding about the possible responses of this threatened species to environmental changes. Lilium pomponium is an endemism of the Ligurian and Maritime Alps spanning along a wide altitudinal gradient (100 and 2000 m a.s.l.), ranging from a Mediterranean to a subalpine climate. Our results show that the populations exposed to different environmental pressures have variations in floral characteristics, these variations likely play an important role in reducing among-populations variability in reproductive output. Germination tests show that the increase in temperature may negatively affect seeds germination capacity. Nevertheless, projections of thermal requirement for seed germination under future climatic conditions suggest that populations will probably respond to future temperature increase shifting their germination phenology. Moreover, in the future the species may find suitable ecological conditions for seed germination in new areas at higher altitudes. Finally, genetic analysis suggests that there is no clear pattern of diversity and differentiation between populations, which may be related to the topographic complexity of the areas and to the biogeographical history of the species. Overall, the results obtained suggest that high among-populations variability found in L. pomponium may be a bet-hedging strategy to cope with unpredictable environmental conditions occurring in Mediterranean climate and that it might also represent a successful strategy to face the future environmental change.

Rozprawę doktorską stanowią cztery anglojęzyczne artykuły: 1) Chrzanowska A., Jadwiszczak K.A. 2015. Disappearing population of Betula humilis Schrk. on the Maliszewskie Lake, NE Poland. Biodiversity: Research and Conservation, 37(1): 69-73 2) Chrzanowska A., Jadwiszczak K.A., Kłosowski S., Banaszek A., Sozinov O.V. 2016. Sexual reproduction efficiency and genetic diversity of endangered Betula humilis Schrk. populations from edge and sub-central parts of its range. Folia Geobotanica 51: 161-173 3) Bona A., Petrova G., Jadwiszczak K.A. 2018. Unfavourable habitat conditions can facilitate hybridisation between the end angered Betula humilis and its widespread relatives B. pendula and B. pubescens. Plant Ecology&Diversity 11: 295-306 4) Bona A., Kulesza U., Jadwiszczak K.A. 2019. Clonal diversity, gene flow and seed production in endangered populations of Betula humilis Schrk. Tree Genetics &Genomes, DOI: 10.1007/s11295-019-1357-2
The genetic diversity of plant populations results from the history of the species and contemporary factors, such as evolutionary processes, habitat conditions and species biology. As many peripheral populations are also ecologically marginal, their genetic diversity and demographic performance are particularly influenced by currently acting factors. The shrub birch, Betula humilis, is a glacial relict in central and western Europe. The primary aim of the PhD thesis was to define the factors that currently shape the genetic diversity of B. humilis populations at the south-western margin of its range. The efficiency of generative reproduction, the frequency of hybridisation with closely related tree congeners and the clonal architecture of the shrub birch populations under different habitat conditions were investigated. The analysis of sexual reproduction revealed that unfavourable habitat conditions, especially in peripheral localities, can reduce the effectiveness of sexual reproduction. Hybridization does not affect the genetic variability of B. humilis, as the proportion of hybrid individuals was very low. In marginal populations, the aggregated type of clonal growth dominates. Nevertheless, the substantial clonal and genetic diversities implied that the clumped growth of the shrub birch clones did not prevent successful crosspollination.
Poziom zmienności genetycznej populacji roślin jest konsekwencją historii gatunku i czynników obecnie oddziałujących na populacje, tj. zjawiska ewolucyjne, warunki środowiska czy cechy biologii gatunku. Populacje zlokalizowane na granicy zasięgu gatunku często są również ekologicznie marginalne, dlatego ich zróżnicowanie genetyczne i demograficzne znajduje się pod szczególnie silnym wpływem powyższych czynników. Brzoza niska,Betulahumilis, jest reliktem glacjalnym w centralnej i zachodniej części Europy. Głównym celem badań była analiza czynników kształtujących zmienność genetyczną w populacjach B. humilisna południowo-zachodnim krańcu zasięgu. W pracy zbadano efektywność rozmnażania płciowego brzozy niskiej, częstość hybrydyzacji z blisko spokrewnionymi gatunkami drzewiastymi oraz strategię wzrostu klonalnego. Przeprowadzone analizy parametrów rozrodu B. humilis sugerują, że niesprzyjające warunki środowiska, w szczególności w populacjach peryferyjnych, mogą obniżać efektywność rozmnażania płciowego. Hybrydyzacja nie wydaje się znacząco wpływać na zmienność genetyczną brzozy niskiej, jako że udział osobników mieszańcowych był nieznaczny. W marginalnych populacjach B. humilis dominuje kępowa struktura wzrostu klonalnego, jednak znaczny poziom zróżnicowania klonalnego i genetycznego sugerują, że kępowy typ wzrostu nie stanowi znaczącej przeszkody do zachodzenia zapyleń krzyżowych.
Uniwersytet w Białymstoku. Wydział Biologiczno-Chemiczny.

Tese de Doutoramento, Ciências do Mar, especialidade de Ecologia Marinha, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2011
Understanding the factors that determine species geographical ranges is a fundamental issue in ecology and evolutionary biology. Species geographical distribution reflects the range with suitable conditions for their persistence beyond which organisms’ tolerances and capacities are presumably constrained. At peripheral locations, where habitats are often fragmented, population persistence frequently relies on the differentiation of lifehistory traits either by phenotypic plasticity or local adaptation. This capability is particularly relevant for species with limited dispersal of propagules and living in variable physical environments as is the case of many marine macrophytes. In this study the variables population structure, dynamics, demography and investment in fitnessrelated phenotypic traits were investigated at the margin and center of the distribution of Ascophyllum nodosum and/or Fucus serratus. These are two ecologically similar and phylogenetically related brown seaweed species with very different life-spans, growth rates and phylogeographical histories. Additionally, the effects of different sources of disturbance on marginal populations of both species were experimentally evaluated. The population structure and dynamics of F. serratus was similar at central and southern border locations but these marginal populations were more constrained in habitat, restricted to a narrower vertical range on the lower intertidal. On the contrary, marginal A. nodosum populations occupied a narrower fringe within the same vertical range as central populations, but were denser, with smaller individuals and had higher reproductive output than central ones. Population stochastic growth rate (λs) was lower and more variable in central than edge populations for A. nodosum, but in F. serratus it was much lower and more variable at the southern limit than in the central range. Elasticity analysis showed that fertility elements had a small contribution to λs; this was more sensitive to changes in survival, particularly for loop in A. nodosum and for growth in F. serratus. However, fertility transitions were more important for population growth rate for F. serratus than for A. nodosum. Surprisingly, the reproductive effort and investment of marginal populations of A. nodosum was higher than in central ones, although similar growth rates were found at both locations. The production of defence compounds was higher at central than at marginal populations suggesting a trade-off in the allocation of resources to reproduction and defence dependent on the local habitat conditions. In this context, the results obtained on the effects of human trampling on A. nodosum populations are of great concern given the levels of human frequentation in the northern intertidal zone in Portugal, its southernmost population, and the importance of individuals´ shrinkage for population growth in these marginal populations. Human trampling negatively affected the A. nodosum communities by significantly reducing the cover of A. nodosum at all the experimental trampling intensities tested but also by affecting the abundance of the associated seaweeds. The long-term recovery of these communities was slow for the two highest trampling intensities, and after approximately 4 years the cover of A. nodosum, as well as the structure of the whole community, were still significantly different from control plots. The interactive effects of abrasion, sediment deposition and herbivory in the survival and growth of F. serratus recruits in marginal populations and in its spatially contiguous species F. vesiculosus were also studied. These two species showed different sensibilities to these tested sources of disturbance. The survival of F. serratus recruits was negatively affected by herbivory whereas F. vesiculosus showed significantly lower survival of recruits under the interactive effects of abrasion, sediment deposition and herbivory. Overall, the results show that A. nodosum marginal populations have high capability for differentiation of life-history traits and seem to be able to cope with the environmental conditions experienced at its southern edge location. On the contrary, F. serratus, although exhibiting a similar population structure in central and marginal locations (at more benign intertidal levels), shows very variable population growth rate which might be indicative of its higher sensibility to environmental variation. These differences between marginal populations of both species are likely related to their different lifehistory characteristics and distinct genetic backgrounds. Furthermore, the results of this study show that perturbations negatively affecting both species at their southern limits, like human trampling for A. nodosum and grazing for F. serratus, might disrupt population dynamics and threaten the persistence of populations at these locations.
No cenário actual de alterações climáticas é fundamental, para as áreas da ecologia e da biologia evolutiva, perceber quais os factores que determinam a distribuição geográfica das espécies. A forma como as espécies se distribuem ao longo do gradiente de latitude depende da existência de condições ambientais e interacções biológicas favoráveis à sua ocorrência. Nas regiões periféricas da área de distribuição das espécies ocorre com frequência fragmentação de habitats o que conduz ao isolamento geográfico das populações. Assim, a persistência destas populações está frequentemente dependente da diferenciação de estratégias de vida através do desenvolvimento de plasticidade fenótipica ou adaptação local. Esta capacidade de diferenciação é particularmente relevante para espécies com capacidade limitada de dispersão de propágulos a longa distância, e que vivem em ambientes com grandes flutuações dos parâmetros físicoquímicos, como é o caso de muitas macroalgas. Neste trabalho, foram estudadas a estrutura, dinâmica e demografia de populações marginais e centrais usando como modelos as macroalgas Ascophyllum nodosum e Fucus serratus. O investimento energético em diferentes parâmetros populacionais foi também estudado no limite sul e no centro da distribuição de A. nodosum. Adicionalmente, foram avaliados experimentalmente os efeitos de diferentes fontes de perturbação para as populações marginais das duas espécies. As populações centrais e marginais de F. serratus apresentaram estrutura e dinâmica semelhantes. No entanto, as populações marginais apareceram restritas a níveis mais baixos do intertidal e distribuídas ao longo de uma extensão vertical menor. Contrariamente, as populações marginais de A. nodosum distribuíram-se ao longo de uma faixa mais estreita mas dentro da mesma extensão vertical que as populações centrais. Estas populações marginais de A. nodosum tinham densidades mais elevadas e indivíduos com comprimentos e biomassas mais baixos. A produção de recrutas por individuo adulto foi mais elevada nestas populações do que nas centrais. A taxa de crescimento das populações (λs) foi mais baixa e mais variável nas populações centrais do que nas populações marginais de A. nodosum. Para F. Serratus, λs foi muito mais baixa e variável nas populações do limite sul do que no centro de distribuição. As análises de elasticidade mostraram que os elementos de fertilidade contribuíram pouco para λs que mostrou maior susceptibilidade a mudanças na sobrevivência, em particular para a permanência na mesma classe de tamanho em A. nodosum e para o crescimento em F. serratus. No entanto, as transições de fertilidade foram mais importantes para o crescimento da população em F. serratus do que para A. nodosum. Surpreendentemente, o esforço e investimento reprodutivos das populações marginais de A. nodosum foi maior do que nas populações centrais, apesar das taxas de crescimento terem sido similares nos dois locais. No entanto, a produção de compostos fenólicos de defesa foi mais elevada nas populações centrais do que nas marginais sugerindo que, dependendo das condições locais, os indivíduos de A. nodosum direccionam de forma diferencial os recursos para funções como a reprodução e a defesa. Neste contexto, os resultados obtidos no estudo dos efeitos do pisoteio nas populações de A. nodosum são motivo de grande preocupação: o número de pessoas que frequentam a zona intertidal onde ocorrem as populações marginais de A. nodosum é elevado e foi demonstrado neste trabalho que o pisoteio afecta negativamente as comunidades desta espécie. Estes efeitos são visíveis ao nível da redução da percentagem de cobertura de A. nodosum em todas as intensidades experimentais de pisoteio testadas. Este é um efeito que, afectando o tamanho dos indivíduos, tem o potencial de condicionar o crescimento desta população marginal. A recuperação a longo termo destas comunidades foi demorada para as duas intensidades mais altas de pisoteio; cerca de 4 anos após o pisoteio ter terminado a cobertura de A. nodosum bem como a estrutura de toda a comunidade, nas áreas com maior intensidade de perturbação, eram ainda significativamente diferentes das áreas controlo. Neste trabalho foram também estudados os efeitos interactivos da deposição de sedimento, abrasão e herbivoria na sobrevivência e crescimento de recrutas de F. serratus e de F. vesiculosus. Estas duas espécies mostraram diferentes sensibilidades às fontes de perturbação testadas. A sobrevivência dos recrutas de F. serratus foi negativamente afectada pela herbivoria enquanto F. vesiculosus mostrou sobrevivência de recrutas significativamente mais baixa sobre os efeitos interactivos das três fontes de perturbação testadas. Em conjunto, os resultados deste trabalho mostram que as populações marginais de A. nodosum têm elevada capacidade para a diferenciação de parâmetros populacionais que lhes permitem persistir nas condições ambientais do limite sul da sua distribuição geográfica. Pelo contrário, o F. serratus apresenta uma estrutura de população similar nas localizações centrais e marginais mas nas populações do limite sul aparece em níveis intertidais mais baixos e com condições ambientais menos exigentes. Nas localizações marginais esta espécie apresenta taxas de crescimento populacional muito variáveis que podem ser indicativas da sua maior sensibilidade a perturbações ambientais. Estas diferenças entre as populações marginais das duas espécies estão provavelmente relacionadas com as suas características ecofisiológicas e com distintos patrimónios genéticos. Os resultados deste estudo mostram ainda que as fontes de perturbação que afectam negativamente as duas espécies nos seus limites sul de distribuição, como o pisoteio no caso de A. nodosum e a herbivoria no caso de F. serratus, podem desestabilizar a dinâmica das populações e ameaçar a sua permanência nestes locais.

La dérégulation du compartiment de cellules B est une conséquence importante de l’infection par le virus de l’immunodéficience humaine (VIH-1). On observe notamment une diminution des nombres de lymphocytes B sanguins ainsi qu’une variation des fréquences relatives des différentes populations de lymphocytes B chez les individus infectés par rapport aux contrôles sains. Notre laboratoire a précédemment démontré l’implication des cellules dendritiques dans la dérégulation des lymphocytes B via la roduction excessive de BLyS/BAFF, un stimulateur des cellules B. De plus, lors l’études menées chez la souris transgénique présentant une maladie semblable au SIDA, et chez la souris BLyS/BAFF transgénique, l’infection au VIH-1 fut associée à une expansion de la zone marginale (MZ) de la rate. De façon intéressante, nous observons chez les contrôleurs élites une diminution de la population B ‘mature’ de la MZ. Il s’agit du seul changement important chez les contrôleurs élites et reflète possiblement un recrutement de ces cellules vers la périphérie ainsi qu’une implication dans des mécanismes de contrôle de l’infection. Pour tenter d’expliquer et de mieux comprendre ces variations dans les fréquences des populations B, nous avons analysé les axes chimiotactiques CXCL13-CXCR5, CXCL12-CXCR4/CXCR7, CCL20-CCR6 et CCL25-CCR9. L’étude longitudinale de cohortes de patients avec différents types de progression clinique ou de contrôle de l’infection démontre une modulation des niveaux plasmatiques de la majorité des chimiokines analysées chez les progresseurs rapides et classiques. Au contraire, les contrôleurs élites conservent des niveaux normaux de chimiokines, démontrant leur capacité à maintenir l’homéostasie. La migration des populations de cellules B semble être modulée selon la progression ou le contrôle de l’infection. Les contrôleurs élites présentent une diminution de la population B ‘mature’ de la MZ et une augmentation de la fréquence d’expression du récepteur CXCR7 associé à la MZ chez la souris, suggérant un rôle important des cellules de la MZ dans le contrôle de l’infection au VIH-1. De façon générale, les résultats dans cette étude viennent enrichir nos connaissances du compartiment de cellules B dans le contexte de l’infection au VIH-1 et pourront contribuer à élaborer des stratégies préventives et thérapeutiques contre ce virus.
Deregulation of the B-cell compartment is an important consequence of human immunodeficiency virus (HIV-1) infection. We observe a decrease in blood B lymphocyte numbers accompanied by variations in the relative frequency of B cell populations in infected individuals when compared to healthy controls. Our lab has previously exposed the implication of dendritic cells in B-cell deregulation via excessive production of B lymphocyte stimulator (BLyS/BAFF). Additionally, the study of BLYS/BAFF-transgenic mice as well as mice exhibiting an AIDS-like disease revealed an expansion of the marginal zone (MZ) of the spleen. Interestingly, we found reduced relative frequencies of mature MZ-like B cells in the blood of elite controllers while rapid and classic HIV progressors had increased ‘precursor’ MZ-like cells. This variation in elite controllers is the only one observed for all population analyzed and could be the reflection of active recruitment of these cells to the periphery to help control infection. To try and understand these variations in B-cell frequencies we have analyzed the Btropic chemotaxis axes CXCL13-CXCR5, CXCL12-CXCR4/CXCR7, CCL20-CCR6 and CCL24-CCR9. The longitudinal study of patients with varying degrees of disease progression and control shows a modulation of the levels of most chemokines in the blood of rapid and classic progessors. Meanwhile, elite controllers maintain normal levels of these chemokines, demonstrating their ability to preserve homeostasis. Our results suggest that the type of disease progression impacts B-cell migration, resulting in modified B-cell population frequencies. The decrease in mature MZ-like B-cells and the increased frequency of cells expressing CXCR7, a receptor associated to the MZ in mice, in elite controllers suggest an important role for the MZ in controlling HIV-1 infection. Overall, our results provide more information about the B-cell compartment in the context of HIV-1 infection and can contribute to the elaboration of preventive and therapeutic strategies for HIV-1.

Depression increases the risk of suicide death and non-fatal suicide attempt. Between 2 - 6% of persons with depression will die by suicide1 and 25 - 31% of persons with depression will make a non-fatal suicide attempt during their lifetime.2,3 Despite the strong association between depression and suicidal behavior, the vast majority of persons with depression will not engage in suicidal behavior, making it difficult to accurately predict who is at risk for suicide and non-fatal suicide attempt. Identifying high risk persons who should be connected to suicide prevention interventions is an important public health goal. Furthermore, depression often co-occurs with other mental disorders, which may exert an interactive influence on the risk of suicide and suicide attempt. Understanding the joint influence of depression and other mental disorders on suicide outcomes may inform prevention strategies. The goals of this dissertation were to predict suicide and non-fatal suicide attempt among persons with depression and to quantify the causal joint effect of depression and comorbid psychiatric disorders on suicide and suicide attempt. For all three studies, we used data from Danish registries, which routinely collect high-quality data in a setting of universal health care with long-term follow-up and registration of most health and life events.4 In Study 1, we predicted suicide deaths among men and women diagnosed with depression using a case-cohort design (n = 14,737). Approximately 800 predictors were included in the machine learning models (classification trees and random forests), spanning demographic characteristics, income, employment, immigrant status, citizenship, family suicidal history (parent or spouse), previous suicide attempts, mental disorders, physical health disorders, surgeries, prescription drugs, and psychotherapy. In depressed men, we found interactions between hypnotics and sedatives, analgesics and antipyretics, and previous poisonings that were associated with a high risk of suicide. In depressed women, there were interactions between poisoning and anxiolytics and between anxiolytics and hypnotics and sedatives that were associated with suicide risk. The variables in the random forests that contributed the most to prediction accuracy in depressed men were previous poisoning diagnoses and prescriptions of hypnotics and sedatives and anxiolytics. In depressed women, the most important predictors of suicide were receipt of state pension, prescriptions for psychiatric medications (anxiolytics and antipsychotics) and diagnoses of poisoning, alcohol related disorders, and reaction to severe stress and adjustment disorders. Prescriptions of analgesics and antipyretics (e.g., acetaminophen) and antithrombotic agents (e.g., aspirin) emerged as important predictors for both depressed men and women. Study 2 predicted non-fatal suicide attempts among men and women diagnosed with depression using a case-cohort design (n = 17,995). Among depressed men, there was a high risk of suicide attempt among those who received a state pension and were diagnosed with toxic effects of substances. There was also an interaction between reaction to severe stress and adjustment disorder and not receiving psychological help that was associated with suicide attempt risk among depressed men. In depressed women, suicide attempt risk was high in those who were prescribed antipsychotics, diagnosed with specific personality disorders, did not have a poisoning diagnosis, and were not receiving a state pension. For both men and women, the random forest results showed that the strongest contributors to prediction accuracy of suicide attempts were poisonings, alcohol related disorders, reaction to severe stress and adjustment disorders, drugs used to treat psychiatric disorders (e.g., drugs used in addictive disorders, anxiolytics, hypnotics and sedatives), anti-inflammatory medications, receipt of state pension, and remaining single. Study 3 examined the joint effect of depression and other mental disorders on suicide and non-fatal suicide attempts using a case-cohort design (suicide death analysis n = 279,286; suicide attempt analysis n = 288,157). We examined pairwise combinations of depression with: 1) organic disorders, 2) substance use disorders, 3) schizophrenia, 4) bipolar disorder, 5) neurotic disorders, 6) eating disorders, 7) personality disorders, 8) intellectual disabilities, 9) developmental disorders, and 10) behavioral disorders. We fit sex-stratified joint marginal structural Cox models to account for time-varying confounding. We observed large hazard ratios for the joint effect of depression and comorbid mental disorders on suicide and suicide attempts, the effect of depression in the absence of comorbid mental disorders, and for the effect of comorbid mental disorders in the absence of depression. We observed positive and negative interdependence between different combinations of depression and comorbid mental disorders on the rate of suicide and suicide attempt, with variation by sex. Overall, depression and comorbid mental disorders are harmful exposures, both independently and jointly. All of the studies in this dissertation highlight the important role of interactions between risk factors in suicidal behavior among persons with depression. Depression is one of the most commonly assessed risk factors for suicide,5,6 and our findings underscore the value of considering additional risk factors such as other psychiatric disorders, psychiatric medications, and social factors in combination with depression. The results of this dissertation may help inform potential risk identification strategies which may facilitate the targeting of suicide prevention interventions to those most vulnerable.

abstract: ABSTRACT The elephant tree, Bursera microphylla, is at the northern limit of its range in central Arizona. This species is sensitive to frost damage thus limiting its occurrence in more northern areas of the southwest. Marginal populations of B. microphylla are found in mountain ranges of Central Arizona and are known to occur in the rugged mountain range system of the South Mountain Municipal Park (SMMP). Little is known of the distribution of this species within the park and details relevant to the health of both individual plants and the population such as diameter and number of trunks, height, and presence of damage have not been examined. This study was designed, in part, to test the hypothesis that favorable microhabitats at SMMP are created by particular combinations of abiotic features including aspect, slope, elevation and solar radiation. Data on abiotic factors, as well as specific individual plant locations and characteristics were obtained for 100 individuals. Temperature data was collected in vertical transects at different altitudinal levels. Some of these data were used in spatial analyses to generate a habitat suitability model using GIS software. Furthermore, collected data was analyzed using Matlab© software to identify potential trends in the variation of morphological traits. In addition, for comparative purposes similar information at one hundred computer-generated randomly chosen points throughout SMMP was obtained. The GIS spatial analyses indicated that aspect, slope, elevation, and relative solar radiance are strongly associated as major climatic components of the microhabitat of B. microphylla. Temperature data demonstrated that there are significant differences in ambient temperature among different altitudinal gradients with middle elevations being more favorable. Furthermore, analyses performed using Matlab© to explore trends of elevation as a factor indicated that multiple trunk plants are more commonly found at higher elevations than single trunk plants, there is a positive correlation of trunk diameter with elevation, and that canopy volume has a negative correlation with respect to elevation. It was concluded that microhabitats where B. microphylla occurs at the northern limit of its range require a particular combination of abiotic features that can be easily altered by climatic changes.
Dissertation/Thesis
M.S. Applied Biological Sciences 2011