Business owners' action planning and its relationship to business success in three African countries.

A model of business success was developed with motivational resources (locus of control, self-efficacy, achievement motivation, and self-reported personal initiative) and cognitive resources (cognitive ability and human capital) as independent variables, business owners' elaborate and proactive planning as a mediator, and business size and growth as dependent variables. Three studies with a total of 408 African micro and small-scale business owners were conducted in South Africa, Zimbabwe, and Namibia. Structural equation analyses partially supported the hypotheses on the importance of psychological planning by the business owners. Elaborate and proactive planning was substantially related to business size and to an external evaluation of business success and was a (partial) mediator for the relationship between cognitive resources and business success. The model carries important implications for selection, training, and coaching of business owners. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Constructing and visualizing chemical reaction networks from pi-calculus models

The π-calculus, in particular its stochastic version the stochastic π-calculus, is a common modeling formalism to concisely describe the chemical reactions occurring in biochemical systems. However, it remains largely unexplored how to transform a biochemical model expressed in the stochastic π-calculus back into a set of meaningful reactions. To this end, we present a two step approach of first translating model states to reaction sets and then visualizing sequences of reaction sets, which are obtained from state trajectories, in terms of reaction networks. Our translation from model states to reaction sets is formally defined and shown to be correct, in the sense that it reflects the states and transitions as they are derived from the continuous time Markov chain-semantics of the stochastic π-calculus. Our visualization concept combines high level measures of network complexity with interactive, table-based network visualizations. It directly reflects the structures introduced in the first step and allows modelers to explore the resulting simulation traces by providing both: an overview of a network’s evolution and a detail inspection on demand.     

Bindemittelfreie zeolithische Molekularsiebe der Typen LTA und FAU

Zeolite molecular sieves belong to the most important adsorbents. For dynamic, technical adsorption processes the use of shaped bodies is required. In conventional molecular sieves usually clay type minerals are used as binder. In this paper novel binderless zeolite molecular sieves and their advantages in comparison to binder containing molecular sieves are shown.     

An experiment measuring the effects of personal software process(PSP) training

The personal software process is a process improvement methodology aimed at individual software engineers. It claims to improve software quality (in particular defect content), effort estimation capability, and process adaptation and improvement capabilities. We have tested some of these claims in an experiment comparing the performance of participants who had just previously received a PSP course to a different group of participants who had received other technical training instead. Each participant of both groups performed the same task. We found the following positive effects: the PSP group estimated their productivity (though not their effort) more accurately, made fewer trivial mistakes, and their programs performed more careful error-checking; further, the performance variability was smaller in the PSP group in various respects. However, the improvements are smaller than the PSP proponents usually assume, possibly due to the low actual usage of PSP techniques in the PSP group. We conjecture that PSP training alone does not automatically realize the PSP's potential benefits (as seen in some industrial PSP success stories) when programmers are left alone with motivating themselves to actually use the PSP techniques     

The exact moment for the plastic torsion of a cylindrical bar of elliptical cross section

Summary An exact expression for the limiting moment of the torsion of an isotropic, perfectly plastic elliptical bar has not been previously derived. In this note, the solution of this classical problem is reduced in form to a single quadrature. It is shown by comparison that an approximation due to Sokolovsky is inaccurate for large aspect ratios of semiaxes. Through a transformation of coordinates, the exact solution is also applicable to the plastic torsion of an orthotropic circular cylinder with generators perpendicular to a principal axis. It follows that for highly orthotropic materials an approximate solution derived by Hill may also prove inaccurate.With 1 Figure     

A closed form solution for the limit moment in the plastic torsion of an elliptical cylinder

Summary A compact, closed form solution is obtained for the limiting torque of a perfectly plastic elliptical cylinder.     

Magnetic Behaviour of O2 Confined in Nanopores

The static susceptibility of solid oxygen condensed into nanoporous matrices is measured as a function of temperature and pore diameter. The drastic changes of the qualitative behaviour are interpreted as a cross-over from three- to one-dimensional behaviour.