Retrospective Data Collection in Europe

Retrospective data play an important role in social science research. This paper provides an overview of problems arising during the process and also presents the solutions found in the field. It also shows details of the collection of retrospective data in the Survey of Health, Ageing and Retirement in Europe (SHARE) in the SHARELIFE project

Globale Sichtbarkeitsalgorithmen

In der vorliegenden Arbeit werden zwei grundsätzliche Ansätze zur Lösung des globalen Sichtbarkeitsproblems beschrieben und verglichen: Näherungs- und exakte Verfahren. Als Beispiel für die exakten Verfahren wird das sog. Visibility Skeleton eingehend untersucht und für verschiedene Spezialfälle angepasst

The anxiolytic effects of a Valerian extract is based on Valerenic acid

BACKGROUND: Valerian is commonly used for the treatment of insomnia and anxiety. Valerian extracts allosterically modulate GABA-A receptors and induced an anxiolytic activity. This activity is closely related to valerenic acid. In the present experiments it was investigated whether acetoxy valerenic acid may interfere with the anxiolytic action of valerenic acid. METHODS: Situational anxiety was measured using male CD-1 mice in the elevated plus maze test after oral administration of the test substances. In addition the body core temperature was measured. For the (3)H-GABA binding assay dissected tissue from frontal cortex of male RjHan:WI rats were used. Statistical evaluation was performed by means of the non-parametric Kruskal-Wallies H-test, followed by the two-tailed Mann–Whitney U-test. RESULTS: Adding of acetoxy valerenic acid abolished the anxiolytic action of valerenic acid. There was no effect on body core temperature. Moreover, the valerian extract did not show any affinity to benzodiazepine binding sites. CONCLUSION: The determining compound for the observed anxiolytic effect of the valerian extract is its content of valerenic acid

Retrospective Data Collection in Europe

Abstract Retrospective data play an important role in social science research. This paper provides an overview of problems arising during the process and also presents the solutions found in the field. It also shows details of the collection of retrospective data in the Survey of Health, Ageing and Retirement in Europe (SHARE) in the SHARELIFE project

Globale Rahmenvereinbarungen in der europäischen Automobilzulieferindustrie

Die Entwicklung von Arbeits- und Beschäftigungsbedingungen in der Automobilzulieferbranche wird in erheblichem Maße vom Standortwettbewerb zwischen Hochlohn- und Niedriglohnstandorten geprägt. Die deutschen Standorte stehen dabei insbesondere im Wettbewerbe mit Werken in Mittelosteuropa. Auf Basis von Fallstudien von sechs deutschen Automobilzulieferern und einer Befragung betrieblicher Arbeitnehmervertreter erörtert dieses Discussion Paper die Möglichkeiten und Strategien von Gewerkschaften und betrieblichen Arbeitnehmervertretern, mithilfe von Globalen Rahmenvereinbarungen (GRV) Mindeststandards im Bereich von Arbeits- und Beschäftigungsbedingungen zu schaffen. Dabei werden drei Fragen verfolgt: Welche Ziele und Motive verbinden die Akteure mit dem Abschluss einer GRV? Welche Auswirkungen können im europäischen Raum beobachtet werden? Und welche Faktoren beeinflussen diese Auswirkungen? Die hier diskutierten Daten und Befunde stammen aus dem von der Hans-Böckler-Stiftung geförderten Forschungsprojekt "Standortperspektiven in der Automobilzulieferindustrie"

Comparison of Arterial Wall Models in Fluid-Structure Interaction Simulations

Monolithic fluid-structure interaction (FSI) of blood flow with arterial walls is considered, making use of sophisticated nonlinear wall models. These incorporate the effects of almost incompressibility as well as of the anisotropy caused by embedded collagen fibers. In the literature, relatively simple structural models such as Neo-Hooke are often considered for FSI with arterial walls. Such models lack, both, anisotropy and incompressibility. In this paper, numerical simulations of idealized heart beats in a curved benchmark geometry, using simple and sophisticated arterial wall models, are compared: we consider three different almost incompressible, anisotropic arterial wall models as a reference and, for comparison, a simple, isotropic Neo-Hooke model using four different parameter sets. The simulations show significant quantitative and qualitative differences in the stresses and displacements as well as the lumen cross sections. For the Neo-Hooke models, a significantly larger amplitude in the in- and outflow areas during the heart beat is observed, presumably due to the lack of fiber stiffening. For completeness, we also consider a linear elastic wall using 16 different parameter sets. However, using our benchmark setup, we were not successful in achieving good agreement with our nonlinear reference calculation

Decomposition of Random Errors Inherent to HOAPS-3.2 Near-Surface Humidity Estimates Using Multiple Triple Collocation Analysis

Latent heat fluxes (LHF) play an essential role in the global energy budget and are thus important for understanding the climate system. Satellite-based remote sensing permits a large-scale determination of LHF, which, amongst others, are based on near-surface specific humidity qa. However, the qa random retrieval error (Etot) remains unknown. Here, a novel approach is presented to quantify the error contributions to pixel-level qa of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite (HOAPS, version 3.2) dataset. The methodology makes use of multiple triple collocation (MTC) analysis between 1995-2008 over the global ice-free oceans. Apart from satellite records, these datasets include selected ship records extracted from the Seewetteramt Hamburg (SWA) archive and the International Comprehensive Ocean-Atmosphere Data Set (ICOADS), serving as the in-situ ground reference. The MTC approach permits the derivation of Etot as the sum of model uncertainty EM and sensor noise EN, while random uncertainties due to in-situ measurement errors (Eins) and collocation (EC) are isolated concurrently. Results show an Etot average of 1.1 ± 0.3 g kg-1, whereas the mean EC (Eins) is in the order of 0.5 ± 0.1 g kg-1 (0.5 ± 0.3 g kg-1). Regional analyses indicate a maximum of Etot exceeding 1.5 g kg-1 within humidity regimes of 12-17 g kg-1, associated with the single-parameter, multilinear qa retrieval applied in HOAPS. Multi-dimensional bias analysis reveals that global maxima are located off the Arabian Peninsula

Alcohols as a Means to Inhibit the Formation of Precipitates in Blends of Biodiesel and Fossil Diesel Fuel

The European diesel fuel specification limits the biodiesel content to 7 %. It is, however, desirable to increase the amount of renewables in the transport sector; therefore blending with a higher biogenic fuel content is of interest. Blending of fuels can lead to chemical reactions between fuel components and may result in undesired products. In detail, aged biodiesel from unsaturated FAME and fossil diesel fuels can form oligomers and precipitations with a maximum in the range of B10 to B20. Precursors are oligomers that can be separated from the biodiesel or the blends in an amount of up to 20 %. These oligomers seem to have potency for chemical reactions with fuel components or the engine oil. To prevent tentative problems in the fuel filter, the injecting system and the combustion process itself, the formation of oligomers should be disabled in blends. Alcohols have been proven and tested to dis-solve precipitations in the fuel. However, flash point problems occur, in case the alcohols have too low boiling points. In our tests, some alcohols could be identified to reach the demands of the diesel fuel standard EN 590. As acceptable monovalent alcohols, the longer-chained alcohols 1-octanol, 3-methyl-1-butanol (isoamyl alcohol) and 2-hexyldecan-1-ol were found. The blends with these alcohols both showed acceptable flashpoints according to DIN EN 590 and could prevent the occurrence of precipi-tates when added in a rather low concentration of about 6 to 8 %. Additionally, engine tests were carried out to monitor regulated and non-regulated emissions. The emissions of selected blends (B10+6OctOH, B10+8IsoamylOH, B10+8HexdecOH) were analyzed by using a single cylinder test engine (Farymann Diesel 18W, TIER 4, agricultural 5-mode test). All of these blends showed less NOx emissions than the pure B10 blend without addition of alcohol. For the CO, HC and PM emissions, no remarkable changes could be found. In the case of non-regulated emis-sions, no relevant changes were observed in carbonyl and PAH emissions, relative to the B10 blend without addition of alcohol. In the result, some blends from biodiesel, diesel fuel and alcohols tend to be appropriate to suppress chemical reactions in the fuel and probably in the engine oil. Further research is necessary to explain the chemical interactions that are responsible for the formation of oligomers and their reaction products. Not only chemical but physical bonds can play important roles and are in the focus of current research

Bunker Cave stalagmites: an archive for central European Holocene climate variability

Holocene climate was characterised by variability on multi-centennial to multi-decadal time scales. In central Europe, these fluctuations were most pronounced during winter. Here we present a record of past winter climate variability for the last 10.8 ka based on four speleothems from Bunker Cave, western Germany. Due to its central European location, the cave site is particularly well suited to record changes in precipitation and temperature in response to changes in the North Atlantic realm. We present high-resolution records of δ18O, δ13C values and Mg/Ca ratios. Changes in the Mg/Ca ratio are attributed to past meteoric precipitation variability. The stable C isotope composition of the speleothems most likely reflects changes in vegetation and precipitation, and variations in the δ18O signal are interpreted as variations in meteoric precipitation and temperature. We found cold and dry periods between 8 and 7 ka, 6.5 and 5.5 ka, 4 and 3 ka as well as between 0.7 and 0.2 ka. The proxy signals in the Bunker Cave stalagmites compare well with other isotope records and, thus, seem representative for central European Holocene climate variability. The prominent 8.2 ka event and the Little Ice Age cold events are both recorded in the Bunker Cave record. However, these events show a contrasting relationship between climate and δ18O, which is explained by different causes underlying the two climate anomalies. Whereas the Little Ice Age is attributed to a pronounced negative phase of the North Atlantic Oscillation, the 8.2 ka event was triggered by cooler conditions in the North Atlantic due to a slowdown of the thermohaline circulation