Quenched Chiral Perturbation Theory for Baryons

We develop quenched chiral perturbation theory for baryons using the graded-symmetry formalism of Bernard and Golterman and calculate non-analytic contributions to the baryon masses coming from quenched chiral loops. The usual term proportional to $m_{q}^{3/2}$ is substantially altered due to the cancellation of diagrams with internal quark loops. In addition, the $\eta'$ ``hairpin'' vertex leads to a new correction, proportional to $m_{q}^{1/2}$. We compare our results to numerical lattice data and use them to estimate the size of the quenching error in the octet baryon masses.Comment: 7 pages (An abridged version of this note will appear in the proceedings of Lattice'93. Latex + 14 postscript files, bundled using uufiles. Needs psfig.) UW/PT-93-0

HRM implementation in multinational companies:the dynamics of multifaceted scenarios

This study explores why the subsidiary line managers of multinational companies (MNCs) implement HRM practices differently than intended by headquarters. HRM implementation is understood as a process in which one has to differentiate between a range of multifaceted HRM implementation scenarios. We build on a single case study in a Dutch subsidiary of a US engineering company that we characterised as an extreme case. The analysis comprises in-depth interviews with HRM and line managers and a study of policy documents using multiple iteration cycles with the software ATLAS.ti. Line managers engage in a range of behaviours: they ignore, deviate, imitate, internalise, initiate and/or integrate the delegated practices because they fail to see the value of the content of the practice and the process of execution. The HRM implementation scenarios found, although distinctive, often overlap, evolve or coexist in a dynamic HRM implementation process. We predict a support role for HRM managers in which they facilitate line managers in deviating from intended practices, and initiating new ones, in order to increase the likelihood of successful internalisation and integration

Succession of the sea-surface microlayer in the coastal Baltic Sea under natural and experimentally induced low-wind conditions

The sea-surface microlayer (SML) is located within the boundary between the atmosphere and hydrosphere. The high spatial and temporal variability of the SML's properties, however, have hindered a clear understanding of interactions between biotic and abiotic parameters at or across the air-water interface. Among the factors changing the physical and chemical environment of the SML, wind speed is an important one. In order to examine the temporal effects of minimized wind influence, SML samples were obtained from the coastal zone of the southern Baltic Sea and from mesocosm experiments in a marina to study naturally and artificially calmed sea surfaces. Organic matter concentrations as well as abundance, (3)H-thymidine incorporation, and the community composition of bacteria in the SML (bacterioneuston) compared to the underlying bulk water (ULW) were analyzed. In all SML samples, dissolved organic carbon and nitrogen were only slightly enriched and showed low temporal variability, whereas particulate organic carbon and nitrogen were generally greatly enriched and highly variable. This was especially pronounced in a dense surface film (slick) that developed during calm weather conditions as well as in the artificially calmed mesocosms. Overall, bacterioneuston abundance and productivity correlated with changing concentrations of particulate organic matter. Moreover, changes in the community composition in the field study were stronger in the particle-attached than in the non-attached bacterioneuston. This implies that decreasing wind enhances the importance of particle-attached assemblages and finally induces a succession of the bacterial community in the SML. Eventually, under very calm meteorological conditions, there is an uncoupling of the bacterioneuston from the ULW

Baryons in Partially-Quenched Chiral Perturbation Theory

I discuss the inclusion of baryons into partially-quenched chiral perturbation theory and describe one-loop calculations that have been performed.Comment: Lattice2002(matrixel) : talk presented at Lattice 2002, 7 page

Das Strahlungsfeld im erdnahen Weltraum:Messungen von MATROSHKA DOSTEL an Bord der ISS

The Earth is permanently exposed to Galactic Cosmic Radiation (GCR). The GCR consist of charged particles and are effectively shielded by Earth’s magnetic field and atmosphere. Therefore the radiation exposure on ground is insignificant, but becomes important when leaving the protective atmosphere. Due to the increased radiation exposure, radiation protection is an important field for space exploration. The MATROSHKA experiment was performed to investigate the radiation exposure to humans on the International Space Station (ISS). An anthropomorphic upper-torso phantom equipped with radiation detectors, named after the Russian nesting doll, was brought to space to perform measurements outside and inside the ISS. One of MATROSHKA’s radiation detectors is the DOSimetric TELescope (DOSTEL), which is based on Silicon semiconductor technology. This active instrument allows a time resolved measurement of the radiation field at ISS altitudes. DOSTEL measurements have shown that the spacecraft hull has only a minor effect on the intensity of GCR particles. The radiation exposure mainly depends on the solar modulation of the GCR. Furthermore, the angular distribution of the GCR particles could be estimated by using data obtained with DOSTEL. Besides GCR particles, particles trapped in Earth’s magnetic field in the socalled radiation belts contribute to the radiation exposure. These particles are effectively shielded by the ISS spacecraft hull, and thus, their contribution to the radiation exposure decreases for inside measurements. During the outside measurement, DOSTEL observed a disturbance of the radiation field at ISS altitudes. In July 2004 Earth’s magnetic field was filled with relativistic electrons. The electrons formed a quasi stable radiation belt in the slot region which was observable until November 2004. The additional radiation exposure induced by this temporal phenomenon was estimated and led to important scientific findings, which were necessary for the interpretation of the results of the other MATROSHKA detectors.Die Erde ist kontinuierlich der Galaktischen Kosmischen Strahlung (GCR) ausgesetzt. Die GCR besteht aus geladenen Teilchen, welche durch das Erdmagnetfeld und die Erdatmosphäre abgeschirmt werden, so dass sie für Menschen auf dem Erdboden nur zu einer geringen und damit zu vernachlässigenden Strahlenexposition führen. Verlässt man die schützende Erdatmosphäre steigt die Strahlenexposition durch die kosmische Strahlung an, was dazu führt, dass diese nicht mehr zu vernachlässigen ist und für Astronauten auf der internationalen Raumstation (ISS) deshalb von besonderer Bedeutung ist. Das MATROSHKA Experiment hat sich zur Aufgabe gemacht die Strahlenexposition für Menschen auf der ISS möglichst genau zu bestimmen und hat zu diesem Zweck ein Phantom des menschlichen Oberkörpers mit Strahlungsdetektoren versehen und auf die ISS bringen lassen. Einer der Strahlungsdetektoren des MATROSHKA Experiments ist das DOSimetric TELescope (DOSTEL). Dieses aktive Instrument besteht aus Silizium Halbleiterdetektoren und ist in der Lage eine zeitaufgelöste Vermessung des Strahlungsfeldes auf ISS Flughöhen durchzuführen. Während der beiden MATROSHKA Experimentphasen MTR-1 und MTR-2B hat das DOSTEL Instrument außerhalb und innerhalb der ISS Daten aufgenommen. Die DOSTEL Messungen haben gezeigt, dass die Intensität der GCR Teilchen kaum durch die Hülle der ISS abgeschirmt wird und hauptsächlich von der solaren Modulation der GCR abhängig ist. Außerdem konnte die Winkelverteilung der GCR Teilchen mit Hilfe der DOSTEL Messungen abgeschätzt werden. Neben den GCR Teilchen tragen auch geladene Teilchen, welche im Erdmagnetfeld in den sogenannten Strahlungsgürteln gefangen sind, zur Strahlenexposition bei. Die Außenhaut der ISS schirmt diese Teilchen effektiv ab, so dass die Strahlenexposition durch diese Teilchen innerhalb der ISS deutlich geringer ist. Während der Messungen außerhalb der ISS konnte zudem eine Störung des Strahlungsfeldes auf ISS Höhen festgestellt werden. Im Juli 2004 wurde das Erdmagnetfeld mit relativistischen Elektronen gefüllt, welche einen quasi-stabilen Strahlungsgürtel bildeten. Die zusätzliche Strahlenexposition durch dieses zeitlich begrenzte Phänomen wurde mit DOSTEL bestimmt und lieferte damit wichtige Erkenntnisse zur Interpretation der Messwerte der passiven MATROSHKA Detektoren

Cruise Report R/V "ALKOR" Cruise No. AL439

Dates of the cruise: 04.06.2014 to 19.06.201

Hadron spectroscopy from lattice QCD

I present recent developments in the lattice QCD calculations of the light hadron spectrum. Emphasis is placed on the limitation of the quenched approximation in reproducing the observed spectrum and indications that the discrepancy is reduced by introducing two flavors of light dynamical quarks.Comment: Talk presented at KEK-Tanashi symposium on "Physics of Hadrons and Nuclei", 14-17 Dec. 1998, Tokyo, Japan. To be published in Nucl. Phys. A. 8 pages, 10 figure

Quenched Chiral Perturbation Theory for Vector Mesons

We develop quenched chiral perturbation theory for vector mesons made of light quarks, in the limit where the vector meson masses are much larger than the pion mass. We use this theory to extract the leading nonanalytic dependence of the vector meson masses on the masses of the light quarks. By comparing with analogous quantities computed in ordinary chiral perturbation theory, we estimate the size of quenching effects, observing that in general they can be quite large. This estimate is relevant to lattice simulations, where the $\rho$ mass is often used to set the lattice spacing.Comment: 18 pages, 8 figures, uses REVTeX and epsf.st

Structure functions near the chiral limit

We compute hadron masses and the lowest moments of unpolarized and polarized nucleon structure functions down to pion masses of 300 MeV, in an effort to make unambiguous predictions at the physical light quark mass.Comment: 3 pages, 3 figures, Lattice2002(matrixel