Adaptive network models of collective decision making in swarming systems

We consider a class of adaptive network models where links can only be created or deleted between nodes in different states. These models provide an approximate description of a set of systems where nodes represent agents moving in physical or abstract space, the state of each node represents the agent's heading direction, and links indicate mutual awareness. We show analytically that the adaptive network description captures the phase transition to collective motion in swarming systems and that the properties of this transition are determined by the number of states (discrete heading directions) that can be accessed by each agent.Comment: 8 pages, 5 figure

Factors Influencing Household Solar Adoption in Santiago, Chile

In Santiago, Chile, the market conditions are seemingly excellent for the household adoption of photovoltaic (PV) technology, yet the uptake is negligible. To explore this paradox, the authors conducted a Delphi study to solicit the knowledge of a panel of Chilean PV experts. These efforts yielded 26 factors—both motivations and barriers—impacting the diffusion of PV in Santiago. Of the 26, experts were in consensus on the relative importance of 21. The literature suggests that diffusion of PV technologies is influenced by complex technical, economic, and social factors. Similarly, the experts saw influence from financial, environmental, and energy supply (e.g., electrical reliability) factors. They saw emergent barriers to adoption as being financial, technical, institutional, and knowledge factors. They considered the most important factors influencing adoption to be financial motivations (e.g., subsidies) and financial barriers (e.g., high upfront costs); they considered the least important factors to be environmental motivations (e.g., environmental stewardship) and technical barriers (e.g., concerns with roof mounting). With this knowledge, the authors develop an adoption framework for household PV that describes the interaction among the identified motivations and barriers. This framework informs policy recommendations for Santiago, Chile, and contributes to the body of literature exploring the interconnected systems of factors that influence civil infrastructure in general and PV adoption in particular

Adaptive-network models of swarm dynamics

We propose a simple adaptive-network model describing recent swarming experiments. Exploiting an analogy with human decision making, we capture the dynamics of the model by a low-dimensional system of equations permitting analytical investigation. We find that the model reproduces several characteristic features of swarms, including spontaneous symmetry breaking, noise- and density-driven order-disorder transitions that can be of first or second order, and intermittency. Reproducing these experimental observations using a non-spatial model suggests that spatial geometry may have a lesser impact on collective motion than previously thought.Comment: 8 pages, 3 figure

Subjectivation in rural development: The case of women in Central Chiloé (Chile), 2008-2015

The thesis explores the process of neoliberal subjectivation in rural development in Chiloé, Chile, focusing mainly on the experience of local women. In general, the literature that critically explores rural development in southern Chile centres on the impact that extractivism and economic globalisation have on the environment and local livelihoods. Although these studies address essential issues such as rural-urban migration, the proletarianisation of farmers, and gender and cultural transformations, there is little analysis on the role that development has in shaping the behaviour and subjectivities of the rural population. The thesis aims to fill this gap by focusing on how the national and local state’s development practices and discourses shape people’s understanding of their own lives and their relationships with others. Empirically, the research focuses on a range of relevant governmental programmes during the salmon industry crisis and in the immediate aftermath. It draws on qualitative and quantitative data from diverse primary and secondary sources. Primary data includes interviews with local civil servants, programme implementers and civil society representatives, a socioeconomic household survey and in-depth interviews with local women. The thesis argues that there is no straightforward correspondence between what development intends to do and what occurs in practice. Although the efforts to create responsible, rational economic individuals shape the relation of the Chilean state with the rural poor, parallel state interventions and discourses do not necessarily point towards the same ideal. Building on these contradictions and their culture and knowledge, poor rural women in Central Chiloé find ways to deviate from neoliberal ideals and express subtle yet relevant critiques to the development approach of the Chilean state in rural territories

Dissipative flow and vortex shedding in the Painlev\'e boundary layer of a Bose Einstein condensate

Raman et al. have found experimental evidence for a critical velocity under which there is no dissipation when a detuned laser beam is moved in a Bose-Einstein condensate. We analyze the origin of this critical velocity in the low density region close to the boundary layer of the cloud. In the frame of the laser beam, we do a blow up on this low density region which can be described by a Painlev\'e equation and write the approximate equation satisfied by the wave function in this region. We find that there is always a drag around the laser beam. Though the beam passes through the surface of the cloud and the sound velocity is small in the Painlev\'e boundary layer, the shedding of vortices starts only when a threshold velocity is reached. This critical velocity is lower than the critical velocity computed for the corresponding 2D problem at the center of the cloud. At low velocity, there is a stationary solution without vortex and the drag is small. At the onset of vortex shedding, that is above the critical velocity, there is a drastic increase in drag.Comment: 4 pages, 4 figures (with 9 ps files

Early fragmentation in the adaptive voter model on directed networks

We consider voter dynamics on a directed adaptive network with fixed out-degree distribution. A transition between an active phase and a fragmented phase is observed. This transition is similar to the undirected case if the networks are sufficiently dense and have a narrow out-degree distribution. However, if a significant number of nodes with low out degree is present, then fragmentation can occur even far below the estimated critical point due to the formation of self-stabilizing structures that nucleate fragmentation. This process may be relevant for fragmentation in current political opinion formation processes.Comment: 9 pages, 8 figures as published in Phys. Rev.

Phase transitions in systems of self-propelled agents and related network models

An important characteristic of flocks of birds, school of fish, and many similar assemblies of self-propelled particles is the emergence of states of collective order in which the particles move in the same direction. When noise is added into the system, the onset of such collective order occurs through a dynamical phase transition controlled by the noise intensity. While originally thought to be continuous, the phase transition has been claimed to be discontinuous on the basis of recently reported numerical evidence. We address this issue by analyzing two representative network models closely related to systems of self-propelled particles. We present analytical as well as numerical results showing that the nature of the phase transition depends crucially on the way in which noise is introduced into the system.Comment: Four pages, four figures. Submitted to PR

Dano a outros causado pelo álcool: o papel das variáveis socioculturais

This paper describes the changes in alcohol research, from a traditional individual focus on individual bodily and mental effects, to a broader focus on harm to others. This shift has coincided with broader sequential definitions of the progression from normal through harmful alcohol dependence, both in the specialized epidemiological and also in the newer classificatory systems (DSM 5 and CIE 11 draft). After presenting updated global, regional and chilean data, an international collaborative Project (Alcohol Harm to Others, ATOH) is described, with the participating institutions: the local study and the chilean components of the research team, the conceptual framework of harm to others (families, children, women; neighbors, friends, co-workers; society at large). Ethical aspects and institutional approval are presented and the principal results outlined: socio-demographic data (with special focus on the role of gender, socio-economic level and religiosity/spirituality). The data is presented for the chilean sample, with examples from other participating countries. The complexity of the link between alcohol harm to others and religious and spiritual factors is studied comparing data from several of the participating countries, and the impact upon vulnerable populations, especially women and children. The discussion reviews some of the confounding and intervening factors that could influence the results. The conclusion about prevention and policy development closes the paper.Este artículo describe los cambios en investigación sobre el abuso de alcohol, desde un enfoque tradicional sobre los efectos corporales y mentales en el individuo, a un enfoque amplio sobre el daño a otros. Este cambio ha coincidido con definiciones secuenciales más amplias de la progresión desde el estado normal a la dependencia dañina al alcohol, ambas en la especialidad de la epidemiología y también en los nuevos sistemas de clasificación (DSM 5 y propuesta de CIE 11). Después de presentar datos actualizados globales, regionales y chilenos, se describe un proyecto internacional colaborativo (Daño a Otros por Causa del Alcohol, ATOH) con las instituciones participantes: el estudio local y los componentes chilenos del equipo de investigación, la estructura conceptual de daño a otros (familias, niños, mujeres; vecinos, amigos, compañeros de trabajo; la sociedad en general). Se presenta la aprobación institucional y aspectos éticos, así como se delinean los principales resultados: datos sociodemográficos (con enfoque especial en el rol de género, nivel socioeconómico y espiritualidad/religiosidad). Se presentan los datos de la muestra chilena, con ejemplos de otros países participantes. Se estudia la complejidad del vínculo entre el daño por alcohol a otros y factores religiosos y espirituales, comparando datos de varios de los países participantes, y el impacto sobre poblaciones vulnerables, especialmente mujeres y niños. La discusión revisa algunos de los factores de confusión y de intervención que podrían influenciar los resultados. Se cierra el artículo con conclusiones sobre prevención y desarrollo de normativas.Este artigo descreve as alterações na pesquisa do álcool, a partir de um foco individual tradicional sobre os efeitos orgânicos e mentais individuais, para um foco mais amplo sobre danos a outros. Essa mudança coincidiu com mais amplas definições sequenciais da progressão do normal através de dependência de álcool prejudiciais, tanto na epidemiologia especializada como nos sistemas classificatórios mais recentes (DSM 5 e CIE 11 minuta). Depois de apresentar dados atualizados globais, regionais e chileno, um projeto internacional colaborativo (Alcohol Harm to Others, ATOH) é descrito, com as instituições participantes: o estudo local e os componentes chilenos da equipe de pesquisa, o quadro conceitual do dano a outrem ( famílias, crianças, mulheres, vizinhos, amigos, colegas de trabalho, e sociedade em geral). Aspectos éticos e aprovação institucional são apresentados e os principais resultados delineados: dados sócio-demográficos (com especial destaque para o papel do sexo, nível socioeconômico e espiritualidade / religiosidade). Os dados são apresentados para a amostra chilena, com exemplos de outros países participantes. A complexidade da relação entre efeitos nocivos do álcool para os outros e fatores religiosos e espirituais é estudada comparando os dados de vários dos países participantes, bem como o impacto sobre populações vulneráveis, especialmente mulheres e crianças. A discussão revê alguns dos fatores de confusão e intervenientes que poderiam influenciar os resultados. A conclusão sobre a prevenção e desenvolvimento de políticas define o papel