Forschungsprogramm "Arbeitsmarktpolitik" am Wissenschaftszentrum Berlin: Ansätze zur vergleichenden Wirkungsanalyse

"Am Internationalen Institut für Management und Verwaltung (IIMV) des Wissenschaftszentrums Berlin (WZB) wurde Arbeitsmarktforschung im kleineren Rahmen seit 1974 betrieben; seit 1979 konzentriert sich einer der beiden Institutsteile (IIMV/Arbeitsmarktpolitik) ausschließlich auf international vergleichende Untersuchungen der Voraussetzungen und der Wirkungsweisen selektiver arbeitsmarktpolitischer Maßnahmen. Im Forschungsgebiet "Funktionsweise von Arbeitsmärkten" liegt derzeit das Schwergewicht auf Untersuchungen zum Berschäftigungsverhalten von Betrieben und Haushalten. Im Forschungsgebiet "Aktoren der Arbeitsmarktpolitik" werden international vergleichende Untersuchungen der Organisationsstruktur und Strategien von Gewerkschaften und Arbeitgeberverbänden und Untersuchungen zur Formulierung und Implementierung staatlicher Maßnahmen der Arbeitsmarkt- und Beschäftigungspolitik weitergeführt. Im Hauptteil des Aufsatzes werden die Forschungsansätze des IIMV zur Ermittlung und Erklärung der Wirksamkeit arbeitsmarktpolitischer Instrumente ausführlicher dargestellt."Wirkungsforschung - Methode, Arbeitsmarktpolitik

Uncertainties in global land cover data and its implications for climate change mitigation policies assessment

Land cover maps provide critical input data for global models of land use. Urgent questions exist, such as how much land is available for the expansion of agriculture to combat food insecurity, how high will be competition for land between food and bioenergy in the future as well as how much land is there available for afforestation projects? These questions can only be answered if reliable maps of land cover exist. We put this research in the framework of GEOSS, examine how modeling tools can be used for benefit assessment and design an assessment framework. We illustrate the importance of good quality global land cover maps by using cropland extend from the currently best global maps of land cover namely GLC-2000, MODIS, GlobCover and CropLikelyhood as input for the EPIC model (to model crop yields) and global economic land use model GLOBIOM. We use all of the 4 maps and create a maximum crop extend and map. Based on a baseline map and the maximum crop extend map e model effects of climate policies (e.g. the potentials of substitution of fossil fuels with biofuels)

Testing for aerobic heterotrophic bacteria allows no prediction of contamination with potentially pathogenic bacteria in the output water of dental chair units

Background: Currently, to our knowledge, quality of output water of dental chair units is not covered by specific regulations in the European Union, and national recommendations are heterogeneous. In Germany, water used in dental chair units must follow drinking water quality. In the United States of America, testing for aerobic heterotrophic bacteria is recommended. The present study was performed to evaluate whether the counts of aerobic heterotrophic bacteria correlate with the presence of potentially pathogenic bacteria such as Legionella spp. or Pseudomonas aeruginosa

On the Dirac Structure of the Nucleon Selfenergy in Nuclear Matter

The relativistic structure of the self-energy of a nucleon in nuclear matter is investigated including the imaginary and real components which arise from the terms of first and second order in the NN interaction. A parameterized form of Brueckner $G$ matrix is used for the NN interaction. The effects of the terms beyond the DBHF approximation on quasiparticle energies and the optical potential for nucleon-nucleus scattering are discussed.Comment: 18 pages, Latex including 10 figures using psfi

GNAS1 T393C polymorphism and disease progression in patients with malignant melanoma

<p>Abstract</p> <p>Background</p> <p>Once metastasized, despite a variety of therapeutic options, the prognosis of patients with malignant melanoma (MM) is still poor. Therefore, the search for reliable markers to identify patients with high risk of disease progression is of high clinical importance. We have recently shown that TT genotypes of the single-nucleotide polymorphism (SNP) T393C in the gene <it>GNAS1 </it>are significantly associated with better outcome in a variety of carcinomas.</p> <p>Patients</p> <p>In the present study we assessed whether the T393C SNP is also related to the clinical course in MM. 328 patients with MM were retrospectively genotyped and genotypes were correlated with clinical outcome.</p> <p>Results</p> <p>While the allele frequency in the MM group (fC 0.52) did not significantly differ from that of healthy blood donors, the T393C SNP was associated with tumor progression of MM. Carriers of the C-allele showed a significantly more severe tumor progression as estimated from the time period to develop metastasis (HR 2.2, 95% CI 1.1-3.2, p = 0.017). Proportions of 5-year metastasis-free intervals were 87.1% for TT genotypes and 66.0% for C-allele carriers. Moreover, multivariable Cox regression analysis including tumor stage and melanoma subtype proved the T393C polymorphism to be an independent factor for metastasis (p = 0.012).</p> <p>Conclusions</p> <p>In summary, the <it>GNAS1 </it>T393C SNP represents a genetic host factor for predicting tumor progression also in patients with MM; genotyping of this SNP may contribute to better define patients who could benefit from an early individualized therapy.</p

Non-consensus GLI binding sites in Hedgehog target gene regulation

BACKGROUND: The GLI transcription factors, mediators of the hedgehog signal bind with high affinity to the consensus sequence GACCACCCA. The affinity of variant single substitutions in GLI binding sites has been measured systematically, but the affinities of the variant binding sites appears low compared to the frequency of occurrence of variant sites in known GLI target gene promoters. RESULTS: We quantified transcriptional activation by GLI using PTCH1 promoter based luciferase reporters containing all single substitutions of the GLI consensus binding site. As expected variants with very low affinity did not activate the reporter. Many lower affinity binding sequences are, however, functional in the presence of moderate GLI concentration. Using two natural non-consensus GLI site promoters we showed that substitution of the variant sequences by consensus leads to comparable activity. CONCLUSIONS: Variant GLI binding sites with relatively low affinity can within natural promoters lead to strong transcriptional activation. This may facilitate the identification of additional direct GLI target genes.(VLID)218887

Collective Excitations and Ground State Correlations

A generalized RPA formalism is presented which treats pp and ph correlations on an equal footing. The effect of these correlations on the single-particle Green function is discussed and it is demonstrated that a self-consistent treatment of the single-particle Green function is required to obtain stable solutions. A simple approximation scheme is presented which incorporates for this self-consistency requirement and conserves the number of particles. Results of numerical calculations are given for $^{16}$O using a G-matrix interaction derived from a realistic One-Boson-Exchange potential.Comment: 16 Pages + 2 Figures (included at the end as uuencoded ps-files), TU-18089

Long-Range Correlations and the Momentum Distribution in Nuclei

The influence of correlations on the momentum distribution of nucleons in nuclei is evaluated starting from a realistic nucleon-nucleon interaction. The calculations are performed directly for the finite nucleus \,^{16}O making use of the Green's function approach. The emphasis is focused on the correlations induced by the excitation modes at low energies described within a model-space of shell-model configurations including states up to the sdg shell. Our analysis demonstrates that these long-range correlations do not produce any significant enhancement of the momentum distribution at high missing momenta and low missing energies. This is in agreement with high resolution $(e,e'p)$ experiments for this nucleus. We also try to simulate the corresponding effects in large nuclei by quenching the energy-spacing between single-particle orbits. This yields a sizable enhancement of the spectral function at large momenta and small energy. Such behavior could explain the deviation of the momentum distribution from the mean field prediction, which has been observed in $(e,e'p)$ experiments on heavy nuclei like $^{208}$Pb

Long-Range Correlations in Closed Shell Nuclei

The effects of correlations on the bulk properties of nuclei are investigated in large model spaces including up to 21 single-particle orbits. The evaluation of the single-particle Green function is made feasible by means of the BAGEL approximation. The spectral function for single-nucleon pick-up and removal is investigated for the nuclei $^{16}O$ and $^{40}Ca$ . Special attention is paid to the effects produced by correlations on the calculated ground state properties of closed shell nuclei. It is observed that correlations beyond the Brueckner Hartree Fock approximation tend to improve the results obtained using realistic nucleon nucleon interactions.Comment: 23 pages 4 figures not included, Report Tu-93-081