Nonlocal van der Waals density functional: The simpler the better

We devise a nonlocal correlation energy functional that describes the entire range of dispersion interactions in a seamless fashion using only the electron density as input. The new functional is considerably simpler than its predecessors of a similar type. The functional has a tractable and robust analytic form that lends itself to efficient self-consistent implementation. When paired with an appropriate exchange functional, our nonlocal correlation model yields accurate interaction energies of weakly-bound complexes, not only near the energy minima but also far from equilibrium. Our model exhibits an outstanding precision at predicting equilibrium intermonomer separations in van der Waals complexes. It also gives accurate covalent bond lengths and atomization energies. Hence the functional proposed in this work is a computationally inexpensive electronic structure tool of broad applicability

Different Types of Welfare States? A Methodological Deconstruction of Comparative Research

Research on modern welfare states has been strongly influenced by the theory that they develop according to patterns, which form distinct regimes liberal, corporatist, and social democratic. These regimes are characterized by several key variables, among which the decommodification of labor is heavily weighted. This article examines the operational assumptions, measures, and calculations used in the most widely cited empirical study around which distinct regime theory has developed over the last decade. The findings reveal critical methodological weaknesses in the conceptualization and quantification of decommodification measures, which form the empirical cornerstone of distinct regime theory

A Socio-Economic Analysis of the Three Paths to Social Security Reform

As this century ends, old-age pension systems worldwide are experiencing tremendous strain and undergoing rigorous examination. At issue is the ability of current schemes to survive demographic changes which threaten to bankrupt most OECD (Organization for Economic Cooperation and Development) members\u27 old age pension systems by the early part of the twenty-first century (Peterson, 1996; Steuerle & Bakija, 1994; World Bank, 1994). A variety of proposals have been advanced in response to this concern, which reflect different underlying values and priorities. Varying significantly in their recommendations for the appropriate balance between public and private efforts, these proposals form a continuum of policy choices ranging from the ameliorative model (first advocated by the Organization for Economic Cooperation and Development) to the fully privatized model (recommended by the Cato Institute). Between these two extremes, the World Bank and others recommend diversification of the public-only format by relying more heavily on other retirement-income sources. These three alternatives to pension reform-the ameliorative, mixed and privatized models-have economic and social implications. The emerging field of socio-economic theory merges dimensions of economics and social science to create a broader perspective that accounts for both cost benefit analysis and humanistic considerations. Applying this approach, six socio-economic criteria have been identified to conduct a systematic comparison and assessment of the ameliorative, mixed and privatized paths to Social Security reform

Review of \u3cem\u3eThe Gender Division of Welfare: The Impact of British and German Welfare States.\u3c/em\u3e Mary Daly. Reviewed by Rebecca A. Van Voorhis

Book review of Mary Daly, The Gender Division of Welfare: The Impact of British and German Welfare States. New York: Cambridge University Press, 2000. $64.95 hardcover,$23.95 papercover

Review of \u3cem\u3eWorking Parents and the Welfare State: Family Change and Policy Reform in Scandinavia.\u3c/em\u3e Arnlaug Leira. \u3cem\u3eInventing the Needy: Gender and the Politics of Welfare in Hungary.\u3c/em\u3e Lynne Haney. Reviewed by Rebecca A. Van Voorhis.

Book review of Arnlaug Leira, Working Parents and the Welfare State: Family Change and Policy Reform in Scandinavia. New York: Cambridge University Press, 2002. 65.00. & Lynne Haney, Inventing the Needy: Gender and the Politics of Welfare in Hungary. Berkeley: University of California Press, 2002. 24.95 papercover

Implementation and Assessment of a Simple Nonlocal van der Waals Density Functional

Recently we developed a nonlocal van der Waals density functional (VV09) that has a simple and well-behaved analytic form. In this article, we report a self-consistent implementation of VV09 with an atom-centered basis set. We compute binding energies for a diverse benchmark set and find that VV09 performs well in combination with Hartree–Fock exchange. We compare VV09 with its precursor, discuss likely sources of inaccuracies in both models, and identify some aspects of the methodology where further refinements are desirable.National Science Foundation (U.S.) (NSF CAREER Grant No. CHE-0547877)David & Lucile Packard Foundation (Fellowship

A quasi-Lagrangian study of mid-ocean variability using long range SOFAR floats

Twenty neutrally buoyant SOFAR floats were used in the Mid-Ocean Dynamics Experiment (MODE) to study the structure and variability of the deep ocean currents. The floats were clustered so that the pattern of motions could be resolved (mapping and pattern recognition). A number of float trajectories are shown and the very individual character of their signature is emphasized. Some floats remain nearly stationary for a year whereas others will cover hundreds of kilometers to the south or west in just a few months...

A hybrid memory kernel approach for condensed phase non-adiabatic dynamics

The spin-boson model is a simplified Hamiltonian often used to study non-adiabatic dynamics in large condensed phase systems, even though it has not been solved in a fully analytic fashion. Herein, we present an exact analytic expression for the dynamics of the spin-boson model in the infinitely slow bath limit and generalize it to approximate dynamics for faster baths. We achieve the latter by developing a hybrid approach that combines the exact slow-bath result with the popular NIBA method to generate a memory kernel that is formally exact to second order in the diabatic coupling but also contains higher-order contributions approximated from the second order term alone. This kernel has the same computational complexity as NIBA, but is found to yield dramatically superior dynamics in regimes where NIBA breaks down---such as systems with large diabatic coupling or energy bias. This indicates that this hybrid approach could be used to cheaply incorporate higher order effects into second order methods, and could potentially be generalized to develop alternate kernel resummation schemes