The conductivity measure for the Anderson model

We study the ac-conductivity in linear response theory for the Anderson tight-binding model. We define the electrical ac-conductivity and calculate the linear-response current at zero temperature for arbitrary Fermi energy. In particular, the Fermi energy may lie in a spectral region where extended states are believed to exist

What do Bayesian methods offer population forecasters?

The Bayesian approach has a number of attractive properties for probabilistic forecasting. In this paper, we apply Bayesian time series models to obtain future population estimates with uncertainty for England and Wales. To account for heterogeneity found in the historical data, we add parameters to represent the stochastic volatility in the error terms. Uncertainty in model choice is incorporated through Bayesian model averaging techniques. The resulting predictive distributions from Bayesian forecasting models have two main advantages over those obtained using traditional stochastic models. Firstly, data and uncertainties in the parameters and model choice are explicitly included using probability distributions. As a result, more realistic probabilistic population forecasts can be obtained. Second, Bayesian models formally allow the incorporation of expert opinion, including uncertainty, into the forecast. Our results are discussed in relation to classical time series methods and existing cohort component projections. This paper demonstrates the flexibility of the Bayesian approach to simple population forecasting and provides insights into further developments of more complicated population models that include, for example, components of demographic change

Influence of Venture Capital Financing on the Growth of Micro, Small and Medium Enterprises in Kenya: The Case Study of Nairobi County

Greatest potentials in driving economies of the developing countries such as Kenya are within the Micro, Small and Medium Enterprises sector which account for almost over 90% of the businesses in these countries. Information asymmetries however, raise the pricing of credit to MSMEs in developing countries and Kenya in particular as well as the high levels of informality within the sector and inadequate systems of collateral verification which hinder the lending. In this 21st century MSMEs should focus beyond bank financing to meet their capital structure needs if they are to fully realize growth and job-creation potential. Via a descriptive survey this study examined the influence of venture capital financing on the growth of Micro, Small and Medium Enterprises (MSMEs), with a focus on venture capital firms in Nairobi-Kenya that have financed MSMEs in the country. Findings indicated that indeed both the venture capital finances and the capitalist expertise were crucial in fast growth of the MSMEs. However information asymmetry gap need to be bridged so as to ensure that MSMEs get a fair operation ground in comparison with the other big players in the developing economies that they operate such as Kenya. This however requires better policies setting by governments so as to encourage the venture capitalist and business angels’ environment. This study provides resource information on venture capital financing and its influences on growth of MSMEs that the government and other stakeholders need in generation of appropriate policy actions that enhance economic development and growth for the achievement of the millennium development goals as stipulated in the vision 2030. Keywords: Venture Capital Financing, Growth, Micro Small and Medium Enterprises, Kenya, Nairobi County

Einfacharbeit in der Industrie

Die Studie betont die Entwicklungsdynamiken industrieller Einfacharbeit und vertritt die These, dass diese kein Auslaufmodell in der Wirtschaft ist. Es wird zum einen gezeigt, dass trotz einer unbestrittenen Erosion gering qualifizierter Tätigkeiten in der Industrie in den letzten Jahrzehnten von einem stabilen Sockel industrieller Einfacharbeit auszugehen ist. Zum zweiten werden die industriellen Hochburgen der Einfacharbeit identifiziert. Zum dritten wird belegt, dass industrielle Einfacharbeit keine Referenzfolie prekärer Beschäftigung ist. Viertens werden arbeitsorganisatorische Muster von Einfacharbeit entwickelt: diese erschöpfen sich nicht in klassisch-tayloristischen Tätigkeiten, sondern umfassen weitere Typen (extra)funktional mehr oder weniger angereicherter Einfacharbeit. Das Papier basiert auf den ersten Ergebnissen eines laufenden DFG-Projektes.The paper outlines the development prospects of low-skill industrial work. The thesis is that this work type is not a negligible factor in advanced societies. First, the paper will establish the claimthat a stable basis of low-skill industrial work exists, despite the erosion of this model in the last decades. Secondly, the industrial strongholds of low-skill work will be identified. Thirdly, it will be proven that this type of 'simple' industrial labor is not generic for precarious work. Moreover, work-organizational paradigms of low-skill work between Taylorist and non-Taylorist patterns of work will be developed. The paper is based on the first result of an ongoing project, funded by the German Research Foundation

Cosmological Hydrodynamics with Multi-Species Chemistry and Nonequilibrium Ionization and Cooling

We have developed a method of solving for multi-species chemical reaction flows in non--equilibrium and self--consistently with the hydrodynamic equations in an expanding FLRW universe. The method is based on a backward differencing scheme for the required stability when solving stiff sets of equations and is designed to be efficient for three-dimensional calculations without sacrificing accuracy. In all, 28 kinetic reactions are solved including both collisional and radiative processes for the following nine separate species: H, H+, He, He+, He++, H-, H2+, H2, and e-. The method identifies those reactions (involving H- and H2+) ocurring on the shortest time scales, decoupling them from the rest of the network and imposing equilibrium concentrations to good accuracy over typical cosmological dynamical times. Several tests of our code are presented, including radiative shock waves, cosmological sheets, conservation constraints, and fully three-dimensional simulations of CDM cosmological evolutions in which we compare our method to results obtained when the packaged routine LSODAR is substituted for our algorithms.Comment: Latex and postscript, 24 pages, with 6 figures. The paper is also available at http://zeus.ncsa.uiuc.edu:8080/~abel/PGas/bib.html Submitted to New Astronom