The Speed of Leaving the Old Job: A Study on Job Changes and Exit into Unemployment during the East German Transition Process

The first period of the transition to a market economy was characterised by a high rate of job-change in many transition countries. This was no different for East Germany. This paper analyses the consequences of the transition process for East German workers in their old job. We quantify the speed at which they change their jobs for a new one or enter unemployment by studying a sample of job spells drawn form the German Socio-Economic Panel-East. The study focuses the period from July 1990 to December 1993, thus a period after the introduction of the German Economic, Monetary, and Social Union. We estimate the effects of important covariates on the transition rates from the old job into a new and into unemployment by a standard competing-risks duration model. Our results suggest that the speed of exit into new jobs rises with skills. We also find that old firms managed to keep workers with relatively good job matches. The special short-time allowances, a labour market program that was in force until the end of 1991, slowed down the exit rate into unemployment prior to its end. We find that workers increased their rate of job-change temporarily at around the period in which this program ended

Critical exponents of a three dimensional O(4) spin model

By Monte Carlo simulation we study the critical exponents governing the transition of the three-dimensional classical O(4) Heisenberg model, which is considered to be in the same universality class as the finite-temperature QCD with massless two flavors. We use the single cluster algorithm and the histogram reweighting technique to obtain observables at the critical temperature. After estimating an accurate value of the inverse critical temperature \Kc=0.9360(1), we make non-perturbative estimates for various critical exponents by finite-size scaling analysis. They are in excellent agreement with those obtained with the $4-\epsilon$ expansion method with errors reduced to about halves of them.Comment: 25 pages with 8 PS figures, LaTeX, UTHEP-28

Computer simulation of protein systems

Ligand binding to dihydrofolate reductase (DHFR) is discussed. This is an extremely important enzyme, as it is the target of several drugs (inhibitors) which are used clinically as antibacterials, antiprotozoals and in cancer chemotherapy. DHFR catalyzes the NADPH (reduced nicotinamide adenine dinucleotide phosphate) dependent reduction of dihydrofolate to tetrahydrofolate, which is used in several pathways of purine and pyrimidine iosynthesis, including that of thymidylate. Since DNA synthesis is dependent on a continuing supply of thymidylate, a blockade of DHFR resulting in a depletion of thymidylate can lead to the cessation of growth of a rapidly proliferating cell line. DHFR exhibits a significant species to species variability in its sensitivity to various inhibitors. For example, trimethoprim, an inhibitor of DHFR, binds to bacterial DHFR's 5 orders of magnitude greater than to vertebrate DHFR's. The structural mechanics, dynamics and energetics of a family of dihydrofolate reductases are studied to rationalize the basis for the inhibitor of these enyzmes and to understand the molecular basis of the difference in the binding constants between the species. This involves investigating the conformational changes induced in the protein on binding the ligand, the internal strain imposed by the enzyme on the ligand, the restriction of fluctuations in atom positions due to binding and the consequent change in entropy

The Anomalous Hall effect in re-entrant AuFe alloys and the real space Berry phase

The Hall effect has been studied in a series of AuFe samples in the re-entrant concentration range, as well as in the spin glass range. The data demonstrate that the degree of canting of the local spins strongly modifies the anomalous Hall effect, in agreement with theoretical predictions associating canting, chirality and a real space Berry phase. The canonical parametrization of the Hall signal for magnetic conductors becomes inappropriate when local spins are canted.Comment: 4 pages, 1 eps figur

Gradual Certified Programming in Coq

Expressive static typing disciplines are a powerful way to achieve high-quality software. However, the adoption cost of such techniques should not be under-estimated. Just like gradual typing allows for a smooth transition from dynamically-typed to statically-typed programs, it seems desirable to support a gradual path to certified programming. We explore gradual certified programming in Coq, providing the possibility to postpone the proofs of selected properties, and to check "at runtime" whether the properties actually hold. Casts can be integrated with the implicit coercion mechanism of Coq to support implicit cast insertion a la gradual typing. Additionally, when extracting Coq functions to mainstream languages, our encoding of casts supports lifting assumed properties into runtime checks. Much to our surprise, it is not necessary to extend Coq in any way to support gradual certified programming. A simple mix of type classes and axioms makes it possible to bring gradual certified programming to Coq in a straightforward manner.Comment: DLS'15 final version, Proceedings of the ACM Dynamic Languages Symposium (DLS 2015

Energy Distribution in disordered elastic Networks

Disordered networks are found in many natural and artificial materials, from gels or cytoskeletal structures to metallic foams or bones. Here, the energy distribution in this type of networks is modeled, taking into account the orientation of the struts. A correlation between the orientation and the energy per unit volume is found and described as a function of the connectivity in the network and the relative bending stiffness of the struts. If one or both parameters have relatively large values, the struts aligned in the loading direction present the highest values of energy. On the contrary, if these have relatively small values, the highest values of energy can be reached in the struts oriented transversally. This result allows explaining in a simple way remodeling processes in biological materials, for example, the remodeling of trabecular bone and the reorganization in the cytoskeleton. Additionally, the correlation between the orientation, the affinity, and the bending-stretching ratio in the network is discussed

The adsorption and desorption of ethanol ices from a model grain surface

Reflection absorption infrared spectroscopy (RAIRS) and temperature programed desorption (TPD) have been used to probe the adsorption and desorption of ethanol on highly ordered pyrolytic graphite (HOPG) at 98 K. RAIR spectra for ethanol show that it forms physisorbed multilayers on the surface at 98 K. Annealing multilayer ethanol ices (exposures > 50 L) beyond 120 K gives rise to a change in morphology before crystallization within the ice occurs. TPD shows that ethanol adsorbs and desorbs molecularly on the HOPG surface and shows four different species in desorption. At low coverage, desorption of monolayer ethanol is observed and is described by first-order kinetics. With increasing coverage, a second TPD peak is observed at a lower temperature, which is assigned to an ethanol bilayer. When the coverage is further increased, a second multilayer, less strongly bound to the underlying ethanol ice film, is observed. This peak dominates the TPD spectra with increasing coverage and is characterized by fractional-order kinetics and a desorption energy of 56.3 +/- 1.7 kJ mol(-1). At exposures exceeding 50 L, formation of crystalline ethanol is also observed as a high temperature shoulder on the TPD spectrum at 160 K. (c) 2008 American Institute of Physics

Tinbergen's work: Change and continuity

This article provides an overview of Tinbergen's economic writings, comprising well over 900 publications. Six broad areas have been distinguished to allow for the classification and discussion of Tinbergen's economic work. These six areas embody the change in Tinbergen's areas of interest apart from the shift from physics to economics early in his career. Tinbergen's work, however, is not only characterised by change of areas but also by continuity in approach. To mark this continuity four main characteristics of Tinbergen's work have been elaborated. The article concludes with Tinbergen's observations on the achievements to be expected from scientific research. J. Kol was Associate Professor of International Economics and Economic Integration at the Faculty of Economics of the Erasmus University in Rotterdam; P. de Wolff is Emeritus Professor at the University of Amsterdam and was Director of the Central Planning Bureau in The Hague as successor of J. Tinbergen. The authors are grateful to Mrs. I.M. Lageweg and Mr C.J. van Opijnen for their assistance with references

A Simplified Model of the Causation of Technological Unemployment

Also published in: ‘Jan Tinbergen Selected Papers’, edited by L.H. Klaassen, L.M. Koyck and H.J. Witteveen, Nort- Holland Publishing Company, Amsterdam, 1959, pp. 165-181The purpose of the present paper is to find the influence on employment of some of the outstanding "data" (extra-economic determining factor-). For this purpose, a simplified model has been constructed in which these data and the chief economic variables find their places. Since it is not intended to picture cyclic variations and causations, the model may be called a "long-run model." It excludes some of the most typical cyclical phenomena such as stock-exchange speculation and the existence of small lags of all kinds which are of importance to the explar~ationo f cyclcs but do not seen1 to be so for long-run developments. Since the investigators were interested chiefly in studying the consequences of technological development for employnlent and the consequences of some of the best-known devices to improve employment, spccial attention was given to the corresponding sections of economic life. Thc calculations have been made for the United States prewar structure (using figures for 1910) and for the postwar pre-Roosevelt structure (using averages for 1919-1932