Convergence of all-order many-body methods: coupled-cluster study for Li

We present and analyze results of the relativistic coupled-cluster calculation of energies, hyperfine constants, and dipole matrix elements for the $2s$, $2p_{1/2}$, and $2p_{3/2}$ states of Li atom. The calculations are complete through the fourth order of many-body perturbation theory for energies and through the fifth order for matrix elements and subsume certain chains of diagrams in all orders. A nearly complete many-body calculation allows us to draw conclusions on the convergence pattern of the coupled-cluster method. Our analysis suggests that the high-order many-body contributions to energies and matrix elements scale proportionally and provides a quantitative ground for semi-empirical fits of {\em ab inito} matrix elements to experimental energies.Comment: 4 pages, 3 figure

Predictable Disruption Tolerant Networks and Delivery Guarantees

This article studies disruption tolerant networks (DTNs) where each node knows the probabilistic distribution of contacts with other nodes. It proposes a framework that allows one to formalize the behaviour of such a network. It generalizes extreme cases that have been studied before where (a) either nodes only know their contact frequency with each other or (b) they have a perfect knowledge of who meets who and when. This paper then gives an example of how this framework can be used; it shows how one can find a packet forwarding algorithm optimized to meet the 'delay/bandwidth consumption' trade-off: packets are duplicated so as to (statistically) guarantee a given delay or delivery probability, but not too much so as to reduce the bandwidth, energy, and memory consumption.Comment: 9 page

Relativistic Coupled-Cluster Theory of Atomic Parity Nonconservation: Application to 137^{137}Ba+^+

We report the result of our {\it ab initio} calculation of the $6s ^2S_{1/2} \to 5d ^2D_{3/2}$ parity nonconserving electric dipole transition amplitude in $^{137}\text{Ba}^+$ based on relativistic coupled-cluster theory. Considering single, double and partial triple excitations, we have achieved an accuracy of less than one percent. If the accuracy of our calculation can be matched by the proposed parity nonconservation experiment in Ba$^+$ for the above transition,then the combination of the two results would provide an independent non accelerator test of the Standard Model of particle physics.Comment: 4 pages, 1 figure, Submitted to PR

Signs And Voices: Deaf Culture, Identity, Language, And Arts

This collection, carefully chosen from the recent Signs and Voices Conference, the Presidential Forum on American Sign Language at the Modern Language Association Convention, and other sources, addresses all of the factors now changing the cultural landscape for deaf people. Taken together, the essays in this book and the accompanying DVD point to new directions in a broad range of fields, including cognitive science, deaf studies, disability studies, education, linguistics, literary criticism, philosophy, and psychology. This showcase of innovative and rigorous cross-disciplinary study will prove invaluable to everyone interested in the current state of the Deaf community

Theoretical determination of lifetimes of metastable states in Sc III and Y III

Lifetimes of the first two metastable states in Sc^{2+} and Y^{2+} are determined using the relativistic coupled-cluster theory. There is a considerable interest in studying the electron correlation effects in these ions as though their electronic configurations are similar to the neutral alkali atoms, their structures are very different from the latter. We have made a comparative study of the correlation trends between the above doubly ionized systems with their corresponding neutral and singly ionized iso-electronic systems. The lifetimes of the excited states of these ions are very important in the field of astrophysics, especially for the study of post-main sequence evolution of the cool giant stars.Comment: 13 pages, 1 figure and 5 table

Novel self-assembled morphologies from isotropic interactions

We present results from particle simulations with isotropic medium range interactions in two dimensions. At low temperature novel types of aggregated structures appear. We show that these structures can be explained by spontaneous symmetry breaking in analytic solutions to an adaptation of the spherical spin model. We predict the critical particle number where the symmetry breaking occurs and show that the resulting phase diagram agrees well with results from particle simulations.Comment: 4 pages, 4 figure

Open government ideologies in post-soviet countries

Most research in research areas like e-government, e-participation and open government assumes a democratic norm. The open government (OG) concept is commonly based on a general liberal and deliberative ideology emphasising transparency, access, participation and collaboration, but were also innovation and accountability are promoted. In this paper, we outline a terminology and suggest a method for how to investigate the concept more systematically in different policy documents, with a special emphasis on post-soviet countries. The result shows that the main focus in this regions OG policy documents is on freedom of information and accountability, and to a lesser extent on collaboration, while other aspects, such as diversity and innovation, are more rarely mentioned, if at all

Investigations of Ra+^+ properties to test possibilities of new optical frequency standards

The present work tests the suitability of the narrow transitions $7s \ ^2S_{1/2} \to 6d ^2D_{3/2}$and$7s ^2S_{1/2} \to 6d ^2D_{5/2}$in Ra$^+$for optical frequency standard studies. Our calculations of the lifetimes of the metastable$6d$states using the relativistic coupled-cluster theory suggest that they are sufficiently long for Ra$^+$ to be considered as a potential candidate for an atomic clock. This is further corroborated by our studies of the hyperfine interactions, dipole and quadrupole polarizabilities and quadrupole moments of the appropriate states of this system.Comment: Latex files, 5 pages, 1 figur

An analysis of the policy process of the Indian National Food Security Act of 2013 in relation to urban food insecurity

Background. This thesis explores the Indian National Food Security Act of 2013 (henceforth NFSA) as an expression of Indian food policy, with specific focus on the extent that Indian urban food security was understood, considered and addressed during the policy formation of the NFSA. The NFSA seeks to provide up to 50% of the entire urban population access to the Public Distribution System (PDS). How such figures were agreed upon, and if other urban-focused entitlements were considered in the policy design, is of significance, to not only assess whether the NFSA adequately addresses the full range of urban food insecurity, but to also bring forward the motivations and interests of the policy-makers themselves. Methods. With the overall research objective to elucidate the role that urban food security played in the policy process of the NFSA, three research questions (RQs) arose to identify: RQ1. The main dimensions of urban food insecurity in India, and the urban planning and policy context; RQ2. The main actors involved in the policy process of the NFSA, and the extent to which urban experts were consulted; RQ3. The degree to which urban food security was considered, understood and represented in the policy formulation of the NFSA. Walt and Gilson’s Policy Analysis Triangle was utilised as the conceptual framework, situated within the broader tradition and approach of critical food policy analysis. The research adopted a multi-method approach, using 26 elite semi-structured interviews as the primary data source, and conducting analysis of official policy documents and transcripts of the Lok Sabha debates as secondary data sources. Research was primarily conducted in Delhi, within circles of academics, civil society activists, bureaucrats and experts in think-tanks, to map out and understand how and if entitlements focused on urban food security changed during the NFSA’s formulation and the extent that it garnered attention up to the final Act. Findings. The research analysis suggests that urban food security received limited attention during the formulation of the NFSA, with more focus on a broad food security approach, only differentiating between the urban and rural food insecure through eligibility. There is further evidence of long-standing urban neglect within poverty alleviation policies and a dearth of urban food security discourse within national urban programmes. This is further compounded by policies that affect the urban poor negatively, such as slum demolishment, displacement and illegalisation of slum-dwellers, as well as poor statistical evidence and understanding of urban food security by key policy-makers. The earlier drafts of the NFSA included comprehensive entitlements for the most vulnerable groups in urban areas, indicating that key actors in the policy process showed an understanding and concern towards urban food insecurity. Due to the tensions and negotiations between policy-makers, coupled with the possible undue influence of a key policy-maker, the potential of the NFSA in addressing urban food security was limited. Discussion. The findings suggest that urban food security was not of particular focus for the policy-makers involved in the NFSA, yet the initial draft of the Act, due to the influence of key academics, civil society activists and former bureaucrats within the National Advisory Council (NAC), contained substantial entitlements for urban vulnerable groups. The excising of these entitlements may have substantially weakened the potential of the NFSA to address urban food insecurity, even if perfectly implemented. Ultimately, the influence of growth-focused, economic rationalism among key governmental policy-makers tempered the vast and wide-ranging initial draft, streamlining it so that the content was ultimately only expanding upon existing policies and programmes rather than any novel approaches. More research is needed to more clearly identify and problematise the influence of commercial interests in the legislative branch, as well as to analyse the implementation of the NFSA, for its potential successes or failures. Conclusion. The thesis concludes that key reforms in urban governance and planning, implementing a multidimensional framework in identifying the urban poor, as well as reintroducing the removed entitlements would significantly strengthen the response to urban food insecurity in India. A more robust nutrition security approach would also greatly benefit the urban food insecure. The broader implications highlighted by this thesis is that continued urban neglect, exacerbated by systemic policy failures in addressing urban poverty coupled with the wholesale adoption of economic rationalism, will be a growing crisis for India as its urban populations grow, with little evidence that its existing programmes and policies are suited in addressing the highlighted issues, and sufficient evidence that continued food insecurity will persist despite rising living standards and rising incomes

Access: Multiple Avenues For Deaf People

The companion to Signs and Voices: Deaf Culture, Identity, Language, and Arts, this volume presents an accomplished group of contributors who address the major technological, institutional, and societal advances in access for deaf people, as well as the remaining hurdles