Kink-Based Path Integral Calculations of Atoms He-Ne

An adaptive, kink-based path integral formalism is used to calculate the ground state energies of the atoms He-Ne. The method uses an adaptive scheme to virtually eliminate the sign difficulties. This is done by using a Monte Carlo scheme to identify states that contribute significantly to the canonical partition function and then include them in the wavefunctions to calculate the canonical averages. The calculations use the 6-31G basis set and obtain both precision and accuracy.Comment: To appear in Chem. Phys. Let

Simulation of geometric and electronic degrees of freedom using a kink-based path integral formulation: application to molecular systems

A kink-based path integral method, previously applied to atomic systems, is modified and used to study molecular systems. The method allows the simultaneous evolution of atomic and electronic degrees of freedom. Results for CH$_4$, NH$_3$, and H$_2$O demonstrate this method to be accurate for both geometries and energies. Comparison with DFT and MP2 level calculations show the path integral approach to produce energies in close agreement with MP2 energies and geometries in close agreement with both DFT and MP2 results.Comment: 23 pages, 2 figure

After the doors close: assisting laid-off workers to find jobs

Displaced workers ; Wages ; Unemployment

Estimating the contribution of urban public infrastructure to regional growth

An estimation of components of public capital stock for 38 metropolitan areas from 1953 to 1981, using the perpetual inventory method. These series are used to estimate the effect of public capital stock on regional manufacturing production.Regional economics ; Infrastructure (Economics) ; Capital investments

Cross-sectional analysis of public infrastructure and regional productivity growth

An analysis of the relationship between local public capital stock and regional manufacturing output, inputs, and productivity between 1965 and 1977. Results show that the effect of public capital stock on regional productivity, although limited, cannot be dismissed, and that public infrastructure appears to be a major factor in explaining growth rates of inputs.Infrastructure (Economics) ; Productivity ; Regional economics ; Manufactures

Urban Labor Markets

Urban labor markets are characterized by the spatial proximity of households and businesses, which offers firms and workers advantages that lead to more efficient markets, enhanced productivity, and greater economic success. Nevertheless, the nation's city, while generating a large proportion of the nation's wealth, houses much of the nation's economic disadvantaged workers. This paper describes the current conditions of urban labor markets and outlines a national urban policy agenda that addresses these concerns by taking into account cities' spatial dimension. The paper argues that a national urban labor policy should emphasize the effects of physical and informational proximity on growth, the benefits of efficient urban markets, and the importance of the access of workers to urban labor markers. These characteristics distinguish a national urban policy from simply a national policy targeted at people who happen to live in cities.local, labor, market, urban, Eberts

Public infrastructure and regional economic development

A review of recent empirical studies concerned with how investment in public infrastructure affects various types of state- and local-level economic activity. The relationships between public and private investment are examined and assessed.Infrastructure (Economics) ; Regional economics

The Use of Profiling to Target Services in State Welfare-to-Work Programs: An Example of Process and Implementation

The purpose of this paper is to provide preliminary information about the design of a pilot project to test the efficacy of profiling and referring welfare-to-work participants. Welfare reform requires welfare recipients, with few exceptions, to participate in work activities and ultimately become economically self-sufficient. Welfare recipients possess a wide variation in job readiness skills, ranging from those who are ready and able to work to those who face significant barriers to employment. The challenge of the local administrator of welfare-to-work programs is to target services to those who need them the most. Yet, most programs provide the same services to all participants, regardless of their past work history or skills. Profiling is a management tool that statistically identifies individuals as to the probability that they will obtain employment. The probability is derived from a statistical model using information commonly collected at enrollment interviews. The model estimates the relationship between an individual's propensity to find and hold a job and that person's attributes, work and welfare histories, and local labor market conditions. The paper describes the model and shows how it can be incorporated into existing welfare-to-work programs that emphasize work-related activities.welfare-to-work, profiling, FDSS, Eberts, reemployment

The Contribution of EUV from Clusters of Galaxies to the Cosmic Ionizing Background

Recent observations with the Extreme Ultraviolet Explorer (EUVE) suggest that at least some clusters of galaxies are luminous sources of extreme ultraviolet (EUV) radiation. It is not clear yet whether EUV emission is a general feature of clusters; for the purposes of limiting the contribution to the background radiation, we assume that it is true of most clusters. Assuming that the source of the EUV emission is inverse Compton (IC) scattering of the Cosmic Microwave Background photons by relativistic electrons, we construct a simple model for the expected average emission from clusters as a function of their mass and the redshift of interest. Press-Schechter theory is used to determine the abundance of clusters of various masses as a function of redshift. We determine the amount of background radiation produced by clusters. The total mean intensity, spectrum, and the ionization rates for HI and HeII are determined at present and at a variety of redshifts. Because clusters form by the merger of smaller subclusters, the amount of EUV background radiation should be larger at present than in the past. We compare our results to the ionizing background expected from quasars. We find that while clusters do contribute a significant EUV background, it is less than a percent of that expected from quasars.Comment: 13 pages in emulateapj5 style with 7 figures, accepted for publication in Astrophysical Journa

Integrating knowledge and control into hypermedia-based training environments: Experiments with HyperCLIPS

The issues of knowledge representation and control in hypermedia-based training environments are discussed. The main objective is to integrate the flexible presentation capability of hypermedia with a knowledge-based approach to lesson discourse management. The instructional goals and their associated concepts are represented in a knowledge representation structure called a 'concept network'. Its functional usages are many: it is used to control the navigation through a presentation space, generate tests for student evaluation, and model the student. This architecture was implemented in HyperCLIPS, a hybrid system that creates a bridge between HyperCard, a popular hypertext-like system used for building user interfaces to data bases and other applications, and CLIPS, a highly portable government-owned expert system shell