Individual Determinants of Work Attendance: Evidence on the Role of Personality

We investigate the influence of personality as measured by the Big Five personality scale on absenteeism using representative data for Germany. In particular, the 2005 wave of the German Socio-Economic Panel provides detailed information on socio-economic background characteristics along with a Big Five personality scale. Estimates of a Logit model and of count data regression are used to analyze an empirical model based on the theory of hedonic labour market outcomes. These estimates allow us to test hypotheses on the influence of the Big Five personality traits on work attendance. We find clear negative correlations between the probability to be absent and Conscientiousness as well as Agreeableness. We find a strong positive impact of Neuroticism on work attendance decisions in general and clues for a positive impact of Extraversion among men. When looking at the length of absence occurrences the personality dimensions of Neuroticism and Agreeableness are found to significantly influence male absenteeism. Implications of our results are discussed.absenteeism, Five Factor Model, personality, count data model

Consideration of the relationship between Kepler and cyclotron dynamics leading to prediction of a non-MHD gravity-driven Hamiltonian dynamo

Conservation of canonical angular momentum shows that charged particles are typically constrained to stay within a poloidal Larmor radius of a poloidal magnetic flux surface. However, more detailed consideration shows that particles with a critical charge to mass ratio can have zero canonical angular momentum and so be both immune from centrifugal force and not constrained to stay in the vicinity of a specific flux surface. Suitably charged dust grains can have zero canonical angular momentum and in the presence of a gravitational field will spiral inwards across poloidal magnetic surfaces toward the central object and accumulate. This accumulation results in a gravitationally-driven dynamo, i.e., a mechanism for converting gravitational potential energy into a battery-like electric power source.Comment: 14 pages, 1 figur

Solving large-scale traveling salesman problems with parallel Branch-and-Cut

We introduce the implementation of a parallel Branch-and-Cut algorithm to solve large-scale traveling salesman problems. Rather than using the well-known models of homogeneous distribution and simple Master/Slave communication, we present a more sophisticated distribution that takes the advantage of several independent features of a Branch-and-Cut code. Computational results are reported for several instances of the TSPLIB

What happens when the geomagnetic field reverses?

During geomagnetic field reversals the radiation belt high-energy proton populations become depleted. Their energy spectra become softer, with the trapped particles of highest energies being lost first, and eventually recovering after a field reversal. The radiation belts rebuild in a dynamical way with the energy spectra flattening on the average during the course of many millennia, but without ever reaching complete steady state equilibrium between successive geomagnetic storm events determined by southward turnings of the IMF orientation. Considering that the entry of galactic cosmic rays and the solar energetic particles with energies above a given threshold are strongly controlled by the intensity of the northward component of the interplanetary magnetic field, we speculate that at earlier epochs when the geomagnetic dipole was reversed, the entry of these energetic particles into the geomagnetic field was facilitated when the interplanetary magnetic field was directed northward. Unlike in other complementary work where intensive numerical simulations have been used, our demonstration is based on a simple analytical extension of Stormer's theory. The access of GCR and SEP beyond geomagnetic cut-off latitudes is enhanced during epochs when the Earth's magnetic dipole is reduced, as already demonstrated earlier.Comment: 12 pages, 3 figures (at the end of file), paper accepted for AGU Geophysical Monograph on "Dynamics of the Earth's Radiation Belts and Inner Magnetosphere". Editors : D.Summers, I.R.Mann, D.N.Baker, and M.Schul

Thermodynamical Properties of Hall Systems

We study quantum Hall effect within the framework of a newly proposed approach, which captures the principal results of some proposals. This can be established by considering a system of particles living on the non-commutative plane in the presence of an electromagnetic field and quantum statistical mechanically investigate its basic features. Solving the eigenvalue equation, we analytically derive the energy levels and the corresponding wavefunctions. These will be used, at low temperature and weak electric field, to determine the thermodynamical potential \Omega^{nc} and related physical quantities. Varying \Omega^{nc} with respect to the non-commutativity parameter \theta, we define a new function that can be interpreted as a \Omega^{nc} density. Evaluating the particle number, we show that the Hall conductivity of the system is \theta-dependent. This allows us to make contact with quantum Hall effect by offering different interpretations. We study the high temperature regime and discuss the magnetism of the system. We finally show that at \theta=2l_B^2, the system is sharing some common features with the Laughlin theory.Comment: 20 pages, misprints correcte

Reversed-Spin Quasiparticles in Fractional Quantum Hall Systems and Their Effect on Photoluminescence

The energy, interaction, and optical properties of reversed-spin quasielectrons (QE_R's) in fractional quantum Hall systems are studied. Based on the short range of the QE_R-QE_R repulsion, a partially unpolarized incompressible nu=4/11 state is postulated within Haldane hierarchy scheme. To describe photoluminescence, a reversed-spin fractionally charged exciton hQE_R (QE_R bound to a valence hole h) is predicted. In contrast to its spin-polarized analog, hQE_R is strongly bound and radiative.Comment: 4 pages, 2 figures, paper for EP2DS1

Der lange Weg der Versöhnung – Aspekte des deutsch-namibischen Vergangenheitsdiskurses

Namibia und Deutschland verbindet eine inzwischen weit über hundertjährige Beziehung. Als ehemalige deutsche Kolonie sind in Namibia, wie in vielen anderen afrikanischen Ländern auch, heute noch die Folgen der Kolonialzeit spürbar. Bilder und Erinnerungen des Herero- und Nama-Aufstandes 1904 sind heute in der namibischen Gesellschaft allgegenwärtig und prägen die Identitätsbildung maßgeblich. Seit einigen Jahren erlebt die Völkermords- und Kontinuitätsthese eine wissenschaftliche und gesellschaftliche Konjunktur in Deutschland und liefert auch dem namibischen Akteursfeld Diskussionspotenzial.Ziel des Aufsatzes ist, Aspekte des Dialogs über die Vergangenheit kritisch zu beleuchten. Das Verständnis von Versöhnung unterscheidet sich teils massiv zwischen den beiden Ländern. Insbesondere die Position Namibias entsteht im Spannungsfeld zwischen neuer Identitätsbildung und etablierten politischen und gesellschaftlichen Strukturen. Hierfür werden der historische Kontext und aktuelle Entwicklungen der Beziehung der beiden Länder skizziert und verschiedene Aspekte des Versöhnungsprozesses beleuchtet

Dialkylketones in paperboard food contact materials—method of analysis in fatty foods and comparative migration into liquid simulants versus foodstuffs

Dialkyl diketene dimers are used as sizing agents in the manufacture of paper and board for food contact applications to increase wetting stability. Unbound residues can hydrolyze and decarboxylate into dialkylketones. These non-intentionally added substances (NIAS) have potential to migrate to fatty foods in contact with those packaging materials. In Germany, the Federal Institute for Risk Assessment (BfR) established a specific migration limit (SML) of 5 mg/kg for the transfer of these dialkylketones into foodstuffs. In order to investigate the differences between simulants and real foods, an analytical method was optimized for extraction and quantification of dialkylketones in edible oils and fatty foods by gas chromatography coupled with flame ionization detection (GC-FID), and additionally by gas chromatography with mass spectrometry (GC-MS), to confirm their identification and to quantify them in case of interferences. Dialkylketones are separated from the extracted fat by alkaline saponification of the triglycerides. Dialkylketones migration from paper-based food contact articles into organic solvents isooctane and dichloromethane, in olive and sunflower oils, and in fatty foods (croissants, Gouda, cheddar cheese, and salami was studied). As a result, it was found that the simulating tests, including the edible oil extraction tests, gave migration values that exceeded the SML largely, while the migration with the food samples were largely below the SML.Antía Lestido Cardama is grateful for her predoctoral grant “Programa de axudas á etapa predoutoral” da Xunta de Galicia (Consellería de Cultura, Educación e Ordenación Universitaria)S

The geometry of atmospheric neutrino production

The zenith angle distributions of atmospheric neutrinos are determined by the possible presence of neutrino oscillations and the combination of three most important contributions: (1) geomagnetic effects on the primary cosmic rays, that suppress the primary flux in the Earth's magnetic equatorial region, (2) the zenith angle dependence of the neutrino yields, due to the fact that inclined showers produce more neutrinos, and (3) geometrical effects due to the spherical shell geometry of the neutrino production volume. The last effect has been recognized only recently and results in an important enhancement of the flux of sub--GeV neutrinos for horizontal directions. In this work we discuss the geometrical effect and its relevance in the interpretation of the atmospheric neutrino data.Comment: 26 pages, 11 figure