Ce travail de recherche a pour objet l’analyse de la vulnérabilité et de l’adaptabilité des systèmes agraires face à la variabilité climatique et aux changements sociaux en Basse-Casamance, région où la riziculture est multiséculaire. L’étude s’intéresse à un aspect important du développement rural dans un contexte de conflit armé et pose la problématique de la dynamique de ces systèmes, devenue un enjeu environnemental, socio-culturel, économique et politique. Elle met ainsi l’accent sur les rapports entre le paysan diola et son environnement, au travers des aménagements agricoles d’une ingéniosité remarquable et dont la structuration traduit la profonde appropriation de l’espace et incarne une dimension socio-spatiale fondamentale de l’identité de la région. Produit d’une longue histoire sociale et sociétale, de l’ingéniosité des techniques associées à l’exploitation du milieu et de la diversité des systèmes agraires, la riziculture de Basse-Casamance fait face, depuis plus d’une quarantaine d’années, à de multiples forces externes, aux conséquences environnementales et socioéconomiques décisives. La forte variabilité climatique (pluviométrique notamment), aspect important en milieu tropical, semble être un des éléments déclencheurs des transformations environnementales passées et actuelles observées dans la région. Elle a entraîné d’autres évènements extrêmes aux contours complexes (salinité élevée des eaux et des sols, acidité des sols, ensablement, etc.), rendant ainsi inaptes la riziculture dans de nombreuses parcelles de la région. L’ampleur des modifications est mesurée grâce à une approche géographique globale et multiscalaire, qui intègre à la fois les outils de la géomatique (Télédétection, SIG, Relevés de points GPS) et les travaux de terrain (prélèvements d’échantillons d’eaux et de sols, analyses physico-chimiques, observations directes, enquêtes-ménages et perceptions de la population). Cette approche a conduit à une importante cartographie des faits observés à partir de niveaux diachroniques et a révélé les grandes tendances des mutations sur l’ensemble de la Basse-Casamance et à l’échelle des terroirs rizicoles. L’approche historique a permis de mieux comprendre les fondements de cette riziculture et les conditions de son évolution actuelle. Ce paradigme est grandement influencé par les politiques publiques d’aménagement rizicole mises en œuvre en Basse-Casamance, dans un souci d’amélioration des conditions de vie de la population rurale. Celles-ci se sont, néanmoins, révélées, dans nombre de cas, inefficaces et inefficientes. / The purpose of this research is to analyze vulnerability and adaptability of agrarian systems face to climate variability and social changes in Basse-Casamance, a region where rice growing is a multi-decade. The study focuses on an important aspect of rural development in a context of armed conflict and raises the issue of the dynamics of these systems, which have become an environmental, socio-cultural, economic and political issue. It emphasizes the relationship between the Diola peasant and his environment, through a remarkably ingenious agricultural management, which structuring reflects the deep appropriation of land and embodies a fundamental socio-spatial dimension of the "identity" of the region. Issued from a long social and societal history, from the ingenuity of techniques associated with the exploitation of the environment and the diversity of agrarian systems, rice growing in Basse-Casamance has been facing for more than forty years, multiple external forces, with decisive environmental and socio-economic consequences. The strong climatic variability (rainfall in particular), a key aspect in tropical environment, seems to be one of the triggers of the past and current environmental transformations observed in the region. It has led to other extreme events, with complex contours (high salinity of water and soil, soil acidity, siltation, etc.), therefore, rice growing in many plots of the region has become unpracticable. The magnitude of the changes is measured by a global and multi-scale approach in geography, which integrates both geomatics’ tools (Remote Sensing, GIS, statements of GPS points) and fieldwork (water and soil sampling, physico-chemical analyzes, direct observations, household surveys and people perceptions). This approach led to an important mapping of the observations from diachronic levels and revealed the major trends of the mutations over whole Basse-Casamance and on the scale of rice growing areas. The historical approach has led to a better understanding of the basis of this rice-growing and the conditions under which it is developing. This paradigm is greatly influenced by the public policies in terms of rice growing, implemented in Basse-Casamance, with a view of improving the livelihoods of the rural people. In many cases, however, they have proved to be ineffective and inefficient.

The primary goals of this research were to investigate 3 ecological factors influencing black bear (Ursus americanus) foraging behavior on an Alaskan salmon (Oncorhynchus spp.) stream: fish availability, social dynamics, and human activity. Over 900 observation hours were Jogged at 2 falls from July !-September I 1993-1995; the lower falls were open to public for wildlife viewing, but the upper falls were restricted to research personnel. In general, black bears responded to differences in fish accessibility on both spatial and temporal scales. All years of the study, 3 indices of bear activity (bear minutes, bear numbers, bout duration) and fish capture rates were significantly higher (all Ps <0 I 0) at the upper falls where fishing opportunities were more abundant. Furthermore, seasonal variation in black bear density was indicative of fluctuations in fish accessibility: bear numbers were highest midseason when fish appeared more abundant, but decreased towards the end of the summer. Although many bears fished within 3 to 5 m of one another, the majority of intraspecific interactions (65-75%) were benign as opposed to agonistic with a preponderance of "passive deferrals" where bears detoured around rather than confronted conspecifics. Only 5. 7% of all interactions resulted in reversals or circularity, providing some evidence for a linear dominance hierarchy. The most dominant bears fished where salmon were highly accessible for longer periods of time, therefore capturing more fish than subordinates each year. Of interspecific interactions, black bears were more likely to be displaced when encountering brown bears on the same side rather than opposite sides of the creek. Of 24 recognized bears, 71% were observed from 75-100% of the time at the upper falls; only 8% (2 females) fished solely at the lower falls. Five of 8 bears that fished exclusively at the upper falls (all large males) appeared wary of researchers upon their arrival. Based on quantile regression analyses, we found that visitor numbers acted as a ceiling on fishing duration of black bears at the lower falls in 1994 and 1995. Furthermore, 2 habituated bears seen frequently at the lower falls spent less time in view (maximum values) as visitor group size increased.

No description available.

abstract: A key factor in the success of social animals is their organization of work. Mathematical models have been instrumental in unraveling how simple, individual-based rules can generate collective patterns via self-organization. However, existing models offer limited insights into how these patterns are shaped by behavioral differences within groups, in part because they focus on analyzing specific rules rather than general mechanisms that can explain behavior at the individual-level. My work argues for a more principled approach that focuses on the question of how individuals make decisions in costly environments. In Chapters 2 and 3, I demonstrate how this approach provides novel insights into factors that shape the flexibility and robustness of task organization in harvester ant colonies (Pogonomyrmex barbatus). My results show that the degree to which colonies can respond to work in fluctuating environments depends on how individuals weigh the costs of activity and update their behavior in response to social information. In Chapter 4, I introduce a mathematical framework to study the emergence of collective organization in heterogenous groups. My approach, which is based on the theory of multi-agent systems, focuses on myopic agents whose behavior emerges out of an independent valuation of alternative choices in a given work environment. The product of this dynamic is an equilibrium organization in which agents perform different tasks (or abstain from work) with an analytically defined set of threshold probabilities. The framework is minimally developed, but can be extended to include other factors known to affect task decisions including individual experience and social facilitation. This research contributes a novel approach to developing (and analyzing) models of task organization that can be applied in a broader range of contexts where animals cooperate. / Dissertation/Thesis / Doctoral Dissertation Applied Mathematics for the Life and Social Sciences 2016

A existência de opiniões distintas em uma sociedade na qual indivíduos interagem constantemente atraiu o interesse de cientistas sociais e físicos estatísticos. Em 1997, Robert Axelrod propôs um modelo vetorial para o estudo da formação de domínios culturais diferentes em uma rede de agentes interagentes. Nesse modelo, os agentes são representados por um vetor de F componentes em que cada componente assume um dentre Q estados inteiros. O modelo apresenta uma transição de um estado monocultural (ordenado) para um estado multicultural (desordenado) que tem sido estudada na literatura através de parâmetros de ordem tais como o tamanho relativo do maior domínio cultural (S) e a fração de domínios culturais diferentes (g). Desde então, propriedades como robustez à introdução de ruídos, à variação de topologia e à introdução de campos local, global e externo foram investigadas. Nosso trabalho está organizado em três partes principais. Na primeira, apresentamos a proposta de novas medidas baseadas no conceito de atividade por agente para o estudo do modelo de Axelrod na rede quadrada. Mostramos que a variância da atividade do sistema (A) pode ser usada para indicar os pontos de transição e que sua distribuição de frequência pode indicar a ordem da transição. Na segunda, estimamos o diagrama de fases no plano (F,Q) e comparamos resultados obtidos em redes com condição de contorno aberta e fechada. Para isso, utilizamos as susceptibilidades dos parâmetros de ordem S e A para determinar os valores críticos Qc(F) para alguns valores de F. Na terceira, analisamos a formação de domínios culturais com a introdução de agentes persistentes para modelar efeitos de mídia interna. Nossos resultados revelam uma dependência de Qc com a probabilidade de ocupação p de agentes persistentes que nos permite obter o diagrama de fases no plano (p,Q). Interpretamos a linha crítica como resultado da competição de duas forças opostas (denominadas efeito de barreira e efeito de ligação) causadas por agentes não-persistentes que aderem aos persistentes. / The existence of different opinions in a society where individuals constantly interact has attracted the interest of social scientists and statistical physicists. In 1997, Robert Axelrod proposed a vectorial model to study the formation of cultural domains in a network of interacting agents. In this model, the agents are represented by a F components vector in which one from Q integer states is assigned to each component. The model presents a transition from a monocultural state (ordered) to a multicultural one (disordered) that has been studied by using order parameters such as the relative size of the biggest cultural domain (S) and the fraction of different domains (g). Since then, some properties as the robustness to the introduction of noise, to the variation of topology and to the introduction of local, global and external fields were studied. Our work is organized in three main parts. In the first part we present the proposal of new measurements based on the concept of activity per agent to study the Axelrod\'s model in a square lattice. We show the variance of system\'s activity (A) can be used to indicate the transition points and that the system\'s activity frequency distribution can be used to indicate the order of the transition. In the second part we estimate the phase diagram in the (F,Q) plane and compare the results obtained from simulations performed in lattices with open and closed boundary conditions. For this purpose, we use the susceptibility of order parameters S and A to determine the critical values Qc(F) for some values of F. In the third part we analyze the formation of cultural domains by introducing persistent agents to model effects of internal media. Our results reveal a dependence of Qc on the occupation probability p of persistent agents that allows us to obtain the phase diagram in the (p,Q) plane. We interpret the critical locus as a result of two opposite forces (called barrier effect and bonding effect) caused by non-persistent agents which adhere the persistent ones.

The creation of APAs, as other direct-use units of conservation, come from the current demand of linking the preservation of natural patrimonies and historic-cultural in the territories. However, the lack of participation by the local community on the decision-making processes contradicts this possibility. At the RiO Ibirapuita‟s APA, site of this study, this same conflict occurs, due to the lack of adequate knowledge on the farmers‟ characteristics and management practices. In order to cease such deficiency, this study aims to characterize the limits and main dynamics, which were evidenced among the typical Pampa‟s social groups at the Rio Ibirapuita‟s APA. To approach that, based on progressive steps, the Analysis and Diagnosis of the Agrarian Systems was used as the main reference. The initial information collected was based on agroecological characterization and socio-economic aspects of the region, as well as, field surveys for the establishment of pre-typology. The assessed groups were submitted to semi-structured surveys, participative observations and, the use a field logbook. For the data analyses, it was used the Aggregated Value theory, multivariate statistical analysis and, speech analysis. The results highlighted for the Pampa region, the rural characteristic related to the human groups that inhabit that region, since pre-historical times. Thus, with the social-economic profile linked to the beef cattle farming activity and to the territorial disputes, the agrarian structure is based on the large sized rural estates. Through the APA‟s agroecologic characterization, three homogeneous zones were identified, in all of them, the beef cattle farming activity predominated. In the first zone, the one located at the highest altitude and in the southern part, the beef cattle farming activity is hegemonic; in the second zone, in the southwestern part of the region and located at middle altitude, the cattle farming activity shares land with dryland cereal cultivation and; in the third zone, in the northern part and at the lowest altitudes, the cattle farming activity occurs concomitantly with the flooding rice fields by the river shore. The demographic distribution follows the logic of these regions, in one way by being characterized by the large sized farms, and in another, by being dominated by the logical family, which clumps the dwellings and the Rincoes. In the large sized farms we found farmers of the employer segment, divided between business and traditional and / or tourism. In the Rincoes, the farmers of the Family segment are from Estancieira origin, they are also changueiros Employees, Retirees, Quilombo, Merchants, or Occupiers and aggregates. Passing in the hallways, between these two extremes, is the segment of the proletariat, composed by temporary and permanent employees and also by the walkers or teatinos. The types of production systems predominantly practiced in these establishments include beef cattle farming, subdivided into combinations of cattle and grain, cattle and sheep, cattle, sheep and "crops inside fences," and rice. It is possible to point out the relationship between work, gender and the environment. In addition, it is addressed their unique strategies, of the "cattle corridor", rental of animals "per head", the joint sales, tourism and environmental marketing. It appears under this scenario the need to recognize and act to mediate these relationships in order to reduce the discrepancies between social groups, and enjoy the traditional knowledge towards the conservation of agricultural ecosystems and cultural heritage present in the Pampa Biome. / A criação das APAs, como unidades de conservação de uso direto, surge da demanda atual de aliar a preservação do patrimônio natural e histórico-cultural nos territórios. Entretanto, preterir a participação da população local nos processos decisórios e reproduzir a idéia de um perfil cultural ligado a um segmento restrito e afastado da realidade local torna contraditória essa possibilidade. Na APA do Rio Ibirapuitã, objeto do presente estudo, esse mesmo conflito se processa, inclusive pelo desconhecimento das características e práticas dos seus moradores. De maneira a contribuir contra tal deficiência, este trabalho propôs-se a caracterizar os limites e as principais dinâmicas evidenciadas entre os grupos sociais típicos do pampa identificados na APA do Rio Ibirapuitã. Para tanto, procedeu-se metodologicamente utilizando-se como principal referência a Análise e Diagnóstico dos Sistemas Agrários. Inicialmente, foram buscados dados secundários para a caracterização agroecológica e socioeconômica da região e feitas entrevistas de campo para estabelecimento de pré-tipologias. Nos grupos identificados, a investigação constou de entrevistas semi-estruturadas, observação participante e uso do diário de campo. No tratamento dos dados, foram utilizados a Teoria do Valor Agregado para análise econômica, a análise estatística multivariada e a análise de discurso. Nos resultados, identificou-se, para a região do pampa, a característica campestre intimamente ligada às atividades dos grupos humanos que ali habitaram, desde a pré-história, assim como o perfil socioeconômico ligado estreitamente à pecuária e às disputas demarcatórias do território, configurando a estrutura agrária baseada predominantemente nas grandes propriedades pastoris. Na caracterização agroecológica da APA identificaram-se 3 Zonas homogêneas, predominando em todas elas a atividade pecuária. Na mais alta, ao sul, a pecuária é hegemônica; na intermediária, a sudeste, divide espaço com lavouras de grãos de sequeiro; e na zona de altitudes inferiores, ao norte, convive com a lavoura de arroz nas várzeas do rio. A distribuição demográfica segue a lógica dessas zonas, tendo uma frente composta pelas estâncias, centralizada; e outra frente periférica, onde predomina a lógica familiar aglutinando as moradias e formando os Rincões. Nas estâncias são encontrados os tipos de Agricultores do Segmento Patronal, divididos entre Empresariais e Tradicionais típicos e/ou com turismo; nos rincões, os Agricultores do Segmento Familiar, sendo de Origem Estancieira, Assalariados e changueiros, Aposentados, Quilombolas, Comerciantes, ou Ocupantes e agregados. Transitando pelos corredores, entre esses dois pólos, está o Segmento do Proletariado, composto pelos Assalariados temporários e permanentes e pelos Andantes ou teatinos. Os tipos de sistemas de produção predominantemente praticados nos estabelecimentos constam da Pecuária de corte, subdividida nas combinações de Bovinos e grãos, Bovinos e ovinos, Bovinos, ovinos e plantas de cercado ; e do Arroz. Destacam-se nesses tipos de sistemas as relações de trabalho, gênero, e com o ambiente. E, nas estratégias engendradas, sobressaem-se as do gado de corredor , do arrendamento por cabeça , das vendas conjuntas, do turismo e do marketing ambiental. Constata-se, diante desse cenário, a necessidade de reconhecer e atuar na mediação entre tais relações, de modo a diminuir as discrepâncias entre os segmentos sociais e aproveitar o conhecimento tradicional no sentido da conservação dos agroecossistemas e da herança cultural presentes no Bioma Pampa.

L’accès à Internet et sa diffusion en Chine ont transformé profondément le mode de communication, d’expression et de mobilisation de la population chinoise. Internet et d’autres nouvelles technologies sont rapidement saisis tant par les internautes chinois que par le gouvernement. Les premiers cherchent plus de liberté dans un régime autoritaire tandis que ce dernier s’efforce d’encadrer ces nouvelles dynamiques à la fois en ligne et hors ligne afin d’éviter les débordements politiques et ainsi de garder le pouvoir. Cette recherche anthropologique porte sur cet affrontement permanant à partir du processus de formation et d’évolution des micros groupes sociaux actifs sur Internet, grâce à Internet et à cause d’Internet. Les enquêtes de terrain ont porté sur trois groupes réunis autour des thèmes spécifiques (homosexualité, protection de l’environnement, défense du patrimoine culturel) dans la ville de Canton. Ils sont analysés dans le contexte du nouveau paradigme de la gouvernance de l’Etat chinois, qui tente de maitriser ces dynamiques à travers une participation programmée à la gestion des problèmes sociaux aux côtés du gouvernement. Entre ouverture économique et clôture politique, la mise en réseaux des acteurs malgré tous les contrôles institués laisse aux initiatives une place comprimée mais réelle et une autonomie relative de proposition. / Internet and its dissemination in China have profoundly changed the way of communication, expression and mobilization of the Chinese people. The Chinese internet users as well as their government have quickly mastered Internet and new technologies. The former seek more freedom in an authoritarian regime, while the latter endeavors to contain these new dynamics both online and offline, in order to avoid political excesses and so to retain the power. This anthropological research focuses on this permanent confrontation from the formation process and evolution of active social groups on the Internet, who exist thanks to and because of the Internet. The fieldwork centered on three groups around specific issues (homosexuality, environmental protection, cultural heritage protection) in the city of Guangzhou. Using the new paradigm of governance, the Chinese government attempts to control these dynamics through a scheduled participation in the management of social problems for its own interest. Taken between the economic openness and political closure, the networking of the social actors leaves them a compressed but real space and a limited autonomy in spite of all the established controls.

Fat-tailed distributions, characterized by the relation P(x) ∝ x^{−α−1}, are an emergent statistical signature of many complex systems, and in particular of social activities. These fat-tailed distributions are the outcome of dynamical processes that, contrary to the shape of the distributions, is in most cases are unknown. Knowledge of these processes’ properties sheds light on how the events in these fat tails, i.e. extreme events, appear and if it is possible to anticipate them. In this Thesis, we study how to model the dynamics that lead to fat-tailed distributions and the possibility of an accurate prediction in this context. To approach these problems, we focus on the study of attention to items (such as videos, forum posts or papers) in the Internet, since human interactions through the online media leave digital traces that can be analysed quantitatively. We collected four sets of time series of online activity that show fat tails and we characterize them. Of the many features that items in the datasets have, we need to know which ones are the most relevant to describe the dynamics, in order to include them in a model; we select the features that show high predictability, i.e. the capacity of realizing an accurate prediction based on that information. To quantify predictability we propose to measure the quality of the optimal forecasting method for extreme events, and we construct this measure. Applying these methods to data, we find that more extreme events (i.e. higher value of activity) are systematically more predictable, indicating that the possibility of discriminate successful items is enhanced. The simplest model that describes the dynamics of activity is to relate linearly the increment of activity with the last value of activity recorded. This starting point is known as proportional effect, a celebrated and widely used class of growth models in complex systems, which leads to a distribution of activity that is fat-tailed. On the one hand, we show that this process can be described and generalized in the framework of Stochastic Differential Equations (SDE) with Normal noise; moreover, we formalize the methods to estimate the parameters of such SDE. On the other hand, we show that the fluctuations of activity resulting from these models are not compatible with the data. We propose a model with proportional effect and Lévy-distributed noise, that proves to be superior describing the fluctuations around the average of the data and predicting the possibility of an item to become an extreme event. However, it is possible to model the dynamics using more than just the last value of activity; we generalize the growth models used previously, and perform an analysis that indicates that the most relevant variable for a model is the last increment in activity. We propose a new model using only this variable and the fat-tailed noise, and we find that, in our data, this model is superior to the previous models, including the one we proposed. These results indicate that, even if present, the relevance of proportional effect as a generative mechanism for fat-tailed distributions is greatly reduced, since the dynamical equations of our models contain this feature in the noise. The implications of this new interpretation of growth models to the quantification of predictability are discussed along with applications to other complex systems.

One important part of the management of zoo populations is the exchange of animals. The removal of an individual can have unknown effects on the social dynamics of the group. Social network studies are a well-established method to describe the social interactions within a group. This study aims to describe the social interactions in a group of chimpanzees and to test how social dominance rank predicts social interaction patters using a social network approach. Data was collected via observations on Kolmarden Wildlife Parks chimpanzee group, which is composed of seven males and eleven females. A total of 50 h of data was collected over 16 days. This resulted in a dominance rank and four different social networks for different behaviors (touch proximity, proximity, affiliative and agonistic behavior). The eigenvector coefficient, with the notable exception of the proximity network, was rarely correlated with the dominance rank and the highest ranked individual was never the most central. The more dominate individuals had fewer links to others through proximity and affiliative interactions. My analysis of the social network structure provides some evidence that the removal of high-ranking individuals would be unlikely to disproportionally affect the structure of the social network in this group. I highlight the possibility of further analysis such as knock-out analysis (where you examine the consequences of the removal of specific individuals) on existing data and argue that more observations would help to draw up a well-structured plan for translocations of individuals in this group. / En viktig del i förvaltningen av djurparkspopulationer är utbytet av djur. Att flytta en individ från en grupp kan ha okända effekter på gruppens sociala dynamik. Studier av djurs sociala nätverk är en väletablerad metod för att beskriva sociala interaktioner inom en grupp av djur. Syftet med denna studie är att beskriva de sociala interaktionerna i en grupp av schimpanser och testa huruvida en ranking av dominans förutspår mönster i dessa sociala interaktioner genom att tillämpa ’social network analysis’ metoden. Observationsdata samlades in på Kolmårdens djurparks schimpansgrupp, som består av sju hanar och elva honor. Totalt samlades 50 timmar av data under 16 dagar. Detta resulterade i en dominansrankning och fyra olika nätverk för olika typer av sociala interaktioner (närhet med beröring, närhet, affiliativa och agnostiska beteenden). Egienvector koefficienten, med det anmärkningsvärda undantaget för närhets nätverket, var sällan korrelerat med dominansrankningen och den högst rankade individen var aldrig mest central. Mer dominanta individer hade färre länkar till andra genom närhet med beröring och affiliativa interaktioner. Mina analyser av de sociala nätverkens struktur ger vissa bevis för att borttagandet av högt rankade individer inte skulle ge oproportionerliga effekter på den sociala strukturen i denna grupp. Jag uppmärksammar också möjligheterna att med mer analyser som t.ex. knock-out analyser (där man undersöker konsekvensen av att ta bort individer från olika nätverk) på befintlig data, samt mer observationer skulle hjälpa för att kunna göra en väl strukturerad plan för flytt av individer från denna grupp.

Chimpanzees are highly social animals, presenting a wide variety of social interactions among them. In this study, we compared the social dynamics in a group of 20 captive chimpanzees at Kolmården Wildlife Park between two different exhibits: outdoors (summer) and indoors (autumn). Furthermore, different types of enrichment were offered in both environments and we investigated how the presence and the type of enrichment (food-based) affected the social interactions in the group. Then, we used the frequencies of the social interactions to analyse the social dynamics in the group. Our results showed that the chimpanzees had significantly higher frequencies of proximity, allogrooming and displacement in the outdoor exhibit compared to indoor one and higher frequencies of threat and display indoors compared to outdoors. Moreover, we found that associative and affiliative behaviours increased in both outdoor and indoor exhibits when enrichment was absent compared to when it was present and also when enrichment was absent compared to when food-based enrichment was offered. Furthermore, three pairs of individuals, all mother-daughter dyads, were found to have preferred relationships. In the allogrooming network, one female, the only one that was in estrus, was found to be the most common recipient of allogrooming. Finally, the oldest male, father of all offspring, was, as expected, ranked as the most dominant in the group, based on the agonistic interactions. Our results may be used by the zoo staff to further develop their management practices to improve chimpanzees’ welfare.