Viewing the efficiency of chaos control

This paper aims to cast some new light on controlling chaos using the OGY- and the Zero-Spectral-Radius methods. In deriving those methods we use a generalized procedure differing from the usual ones. This procedure allows us to conveniently treat maps to be controlled bringing the orbit to both various saddles and to sources with both real and complex eigenvalues. We demonstrate the procedure and the subsequent control on a variety of maps. We evaluate the control by examining the basins of attraction of the relevant controlled systems graphically and in some cases analytically

Growth Cone Pathfinding: a competition between deterministic and stochastic events

BACKGROUND: Growth cone migratory patterns show evidence of both deterministic and stochastic search modes. RESULTS: We quantitatively examine how these two different migration modes affect the growth cone's pathfinding response, by simulating growth cone contact with a repulsive cue and measuring the resultant turn angle. We develop a dimensionless number, we call the determinism ratio Ψ, to define the ratio of deterministic to stochastic influences driving the growth cone's migration in response to an external guidance cue. We find that the growth cone can exhibit three distinct types of turning behaviors depending on the magnitude of Ψ. CONCLUSIONS: We conclude, within the context of these in silico studies, that only when deterministic and stochastic migration factors are in balance (i.e. Ψ ~ 1) can the growth cone respond constructively to guidance cues

A qualitative Langevin-like model for the coexistence of two distinct granular temperatures

In the present work, we study qualitatively the physics of granular temperature coexistence, for a mixture of two different species. Our model captures its essential aspects and this allows us to get insights on the physical mechanisms of distinct temperature coexistence, in a way which is not obscured by the complexities of kinetic theories or numerical simulations. Our simple model is consistent with limit situations where we should expect equality for the granular temperatures for the mixture.Comment: Accepted to be published on Physica

Bursts in the Chaotic Trajectory Lifetimes Preceding the Controlled Periodic Motion

The average lifetime ($\tau(H)$) it takes for a randomly started trajectory to land in a small region ($H$) on a chaotic attractor is studied. $\tau(H)$ is an important issue for controlling chaos. We point out that if the region $H$ is visited by a short periodic orbit, the lifetime $\tau(H)$ strongly deviates from the inverse of the naturally invariant measure contained within that region ($\mu_N(H)^{-1}$). We introduce the formula that relates $\tau(H)/\mu_N(H)^{-1}$ to the expanding eigenvalue of the short periodic orbit visiting $H$.Comment: Accepted for publication in Phys. Rev. E, 3 PS figure

Nature of choice: unraveling individual decision-making for climate-adaptation, science-participation, and environmental stewardship in Mexico, The

2019 Summer.Includes bibliographical references.Broadly, this dissertation research assesses the determinants of individual decision making that constrain or enable livelihoods, for science-policy outcomes and environmental behaviors. This research draws on traditional frameworks for behavior change but integrates novel concepts that have been established in other fields as influencing choice. Though the sustainability field has relied on traditional frameworks for over the past 50 years, the conceptualization of internal cognitive factors like climate perceptions and motivations as well as environmental, socio-economic, and demographics factors remains siloed in their respective disciplines of social psychology and environmental psychology. This dissertation addresses these deficiencies through conceptual, methodological, and empirical contributions to the field of behavior change research. Conceptually, this dissertation tests the influence of four major frameworks on choice: (1) the theory of planned behavior, which refers to the knowledge, attitudes, and social norms that contribute to behavioral intentions; (2) the volunteer motivations framework, which conceptualizes participation in volunteer programs as due to dispersed motivations to participate; (3) the credibility-relevance-legitimacy framework, which refers to the three components needed for decision-makers to use science for action; and (4) the sustainable livelihoods approach framework that conceptualizes livelihood outcomes as a product of the household assets they control while influenced by their external institutional and environmental vulnerability context. In Chapter 2, I modify the sustainable livelihoods framework by integrating climate perceptions into the livelihood assets that households use to make livelihood decisions, with implications for uptake of adaptation strategies for climate change. In Chapter 3 I integrate the volunteer motivation framework into the credibility-relevance-legitimacy framework, suggesting that both are needed for explaining participation in public participation in science, i.e. citizen science. Finally, in Chapter 4 I integrate the theory of planned behavior with the credibility-relevance-legitimacy framework, to show that both are necessary for understanding changes to conservation knowledge, attitudes, and stewardship behaviors over time. Methodologically, this dissertation also contributes novel techniques for encouraging behavior changes for citizen scientists in Chapters 3 and 4. Specifically, conservation decision-makers were included within the traditional citizen science, water-monitoring training to amplify perceptions of project relevance for conservation programs, to improve participation in citizen science as well as to improve social outcomes of knowledge, attitudes, and stewardship behaviors. In an experimental design, half the citizen scientists received the traditional training, while the other half received the intervention training which included an hour and a half presentation from conservation decision makers. We found that while short term perceptions of the relevance of the program was improved, there was a need to enhance legitimacy of program design (i.e., with the voices of citizen scientists), as many volunteers were more interested in studying water quality than water flow. However, the training did positively influence some measures of conservation knowledge and attitudes, and was able to influence frequency of talking to others about conservation. These findings suggest that program managers in citizen science need to know about citizen scientists' motivations to frame recruitment and retention strategies. Additionally, in Chapter 2 this dissertation empirically tests the role of climate vulnerability and adaptation policy making through an in depth examination of coffee farmer adaptation strategies in the state of Chiapas, Mexico, and what determines adoption of adaptation strategies. These results show that the vulnerability context (including market distance, community location, and experience of disasters) the household assets (including natural, social, and physical capitals), and climate perceptions as an additional asset, play an important role in facilitating adaptation to climate change. This research calls attention to the need for stronger policy making that provides financial encouragement for underutilized adaptation strategies such as crop diversification while simultaneously developing climate workshops to strengthen climate perceptions and encouraging participation in agricultural organizations that facilitate information exchange about climate adaptation strategies. Overall, this dissertation calls attention to the social and ecological impacts that citizen science and sustainable development policies have, and the influence that internal cognitive and socio-economic factors play, as well as external environmental factors, for influencing choice to engage in these activities. Because many of these factors are immutable in the short term – such as environmental or socioeconomic factors – this dissertation broadly suggests that to influence choice, decision makers need to recognize cognitive factors like perceptions of climate change, motivations to participate, and perception of project relevancy. Only when we can understand these cognitive factors can informational interventions be appropriately designed for social and ecological outcomes