Dynamic Density Response of Trapped Interacting Quantum Gases

An expression for the dynamic density response function has been obtained for an interacting quantum gas in Random Phase Approximation (RPA) including first order self and exchange contribution. It involves the single particle wave functions and eigen values. The expression simplifies when diagonal elements are considered. The diagonal elements of the imaginary part of Fourier transformed response function is relevant in the measurement of Bragg scattering cross-section and in several other applications.Comment: 2 pages, 0 figure, conferenc

‘And while I am falling, I listen’: on translation processes in <i>I turned away and she was gone</i> (2014) Jennie Reznek in conversation with Sruti Bala

Jennie Reznek is Co- Artistic Director and Trustee of Magnet Theatre in Cape Town, South Africa. I turned away and she was gone is the fifth solo work that she has developed under the banner of Magnet Theatre. It was nominated for six awards and published by Modjaji Books in 2019. The interview took place in the framework of the research project on translation and performance (in collaboration with the University of Cape Town and the University of Amsterdam, 2016–19) in July 2017 at Adishakti Laboratory for Theatre Arts &amp; Research in Pondicherry, India. Reznek shared her reflections on the artistic processes of translation in the solo performance I turned away and she was gone

Thaan Vuzha Nilam Tharisu: the land without a farmer becomes barren

This report forms a part of the international research project on policy and sustainable agriculture, Policies that Work for Sustainable Agriculture and Regenerated Rural Economies. The report details the findings of one of the constituent studies, undertaken by an Indian NGO, the Society for People's Education and Economic Change (SPEECH). The Importance of this project is that it concentrated on rainfed rather than irrigated agriculture - i.e. the sharp end of rural development in India, and that the focus was very much on the micro-level, looking at policy as seen from the ground. One of the recurring themes throughout the research was the importance of appreciating people as individuals, and in this spirit some of the personal qualities of the research team are shared. The research covers events in sites in the Virudhunagar district of Tamilnadu: Tiruchuli Panchayat Union and the Villur chain of tanks. This is an essentially rural area, where the need for sustainable forms of agriculture and rural livelihoods is clear. The political landscape is fractured and complex (§2.3), and the officials with the responsibility of implementing policy face significant obstacles and disincentives in doing so in response to the needs of local communities

Unmeasured anions: the unknown unknowns

Evidence is emerging that elevated concentrations of the intermediates of the citric acid cycle may contribute to unmeasured anions in critical illness. Both the anion gap and the strong ion gap are used as scanning tools for recognition of these anions. The mechanisms underlying these elevations and their significance require further clarification

Dynamic Reconfiguration with I/O Abstraction

Dynamic reconfiguration is explored in the context of I/O abstraction, a new programming model that defines the communication structure of a system in terms of connections among well-defined data interfaces for the modules in the system. The properties of I/O abstraction, particularly the clear separation of computation from communication and the availability of a module\u27s state information, help simplify the reconfiguration strategy. Both logical and physical reconfiguration are discussed, with an emphasis on a new module migration mechanism that (1) takes advantage of the underlying I/O abstraction model, (2) avoids the expense and complication of state extraction techniques, (3) minimizes the amount of code required for migration and confines that code to a separate section of the program, and (4) is designed to permit migration across heterogeneous hosts and to allow replacemnt of one implementation by another, even if the new implementation is written in another programming language. The flexibility of the migration mechanism is illustrated by presenting three different paradigms for constructing reconfiguration modules that are supported by this new mechanism. A uniform specification mechanism is provided for both logical and physical reconfiguration

An Incremental Distributed Algorithm for Computing Biconnected Components

This paper describes a distributed algorithm for computing the biconnected components of a dynamically changing graph. Our algorithm has a worst case communication complexity of O(b + c) messages for an edge insertion and O(b\u27 + c) messages for an edge removal, and a worst case time complexity of O(c) for both operations, where c is the maximum number of biconnected components in any of the connected components during the operation, b is the number of nodes in the biconnected component containing the new edge, and bprime is the number of nodes in the biconnected component in which the update request is being processed. The algorithm is presented in two stages. First, a serial algorithm is presented in which topology updates occur one at a time. Then, building on the serial algorithm, an algorithm is presented in which concurrent update requests are serialized within each connected component. The problem is motivated by the need to implement casual ordering of messages efifciently in a dynamically changing communication structure

The transient response of global-mean precipitation to increasing carbon dioxide levels

The transient response of global-mean precipitation to an increase in atmospheric carbon dioxide levels of 1% yr(-1) is investigated in 13 fully coupled atmosphere-ocean general circulation models (AOGCMs) and compared to a period of stabilization. During the period of stabilization, when carbon dioxide levels are held constant at twice their unperturbed level and the climate left to warm, precipitation increases at a rate of similar to 2.4% per unit of global-mean surface-air-temperature change in the AOGCMs. However, when carbon dioxide levels are increasing, precipitation increases at a smaller rate of similar to 1.5% per unit of global-mean surface-air-temperature change. This difference can be understood by decomposing the precipitation response into an increase from the response to the global surface-temperature increase (and the climate feedbacks it induces), and a fast atmospheric response to the carbon dioxide radiative forcing that acts to decrease precipitation. According to the multi-model mean, stabilizing atmospheric levels of carbon dioxide would lead to a greater rate of precipitation change per unit of global surface-temperature change

Strategic Network Formation with Attack and Immunization

Strategic network formation arises where agents receive benefit from connections to other agents, but also incur costs for forming links. We consider a new network formation game that incorporates an adversarial attack, as well as immunization against attack. An agent's benefit is the expected size of her connected component post-attack, and agents may also choose to immunize themselves from attack at some additional cost. Our framework is a stylized model of settings where reachability rather than centrality is the primary concern and vertices vulnerable to attacks may reduce risk via costly measures. In the reachability benefit model without attack or immunization, the set of equilibria is the empty graph and any tree. The introduction of attack and immunization changes the game dramatically; new equilibrium topologies emerge, some more sparse and some more dense than trees. We show that, under a mild assumption on the adversary, every equilibrium network with $n$ agents contains at most $2n-4$ edges for $n\geq 4$. So despite permitting topologies denser than trees, the amount of overbuilding is limited. We also show that attack and immunization don't significantly erode social welfare: every non-trivial equilibrium with respect to several adversaries has welfare at least as that of any equilibrium in the attack-free model. We complement our theory with simulations demonstrating fast convergence of a new bounded rationality dynamic which generalizes linkstable best response but is considerably more powerful in our game. The simulations further elucidate the wide variety of asymmetric equilibria and demonstrate topological consequences of the dynamics e.g. heavy-tailed degree distributions. Finally, we report on a behavioral experiment on our game with over 100 participants, where despite the complexity of the game, the resulting network was surprisingly close to equilibrium.Comment: The short version of this paper appears in the proceedings of WINE-1

Co-evolution of strategy and structure in complex networks with dynamical linking

Here we introduce a model in which individuals differ in the rate at which they seek new interactions with others, making rational decisions modeled as general symmetric two-player games. Once a link between two individuals has formed, the productivity of this link is evaluated. Links can be broken off at different rates. We provide analytic results for the limiting cases where linking dynamics is much faster than evolutionary dynamics and vice-versa, and show how the individual capacity of forming new links or severing inconvenient ones maps into the problem of strategy evolution in a well-mixed population under a different game. For intermediate ranges, we investigate numerically the detailed interplay determined by these two time-scales and show that the scope of validity of the analytical results extends to a much wider ratio of time scales than expected