Photon-photon interaction in axial channeling

We investigate the possibility that high-energy photons are channeled, when passing through an oriented single crystal, due to Delbrück scattering. For this purpose the exact electron propagator for the single-string model is constructed. Starting from a separation of variables, we solve the Dirac equation for a cylindrical electrostatic potential. The propagator for such external fields is constructed from solutions of the radial Dirac equation. This propagator is applied to a calculation of the S matrix for Delbrück scattering. We specify the conditions under which photon channeling takes place. Unfortunately these conditions are only matched for a very small fraction of those photons being produced by channeled electrons

Asylum and refugee policy of the European Union: international protection as a “windfall”?

El trabajo explica la Política de asilo y refugio de la Unión Europea, describiendo sus elementos e instrumentos normativos más importantes. Luego, analiza las dificultades experimentadas en la implementación de esa política al interior de los estados miembros, utilizando para ello informes de organismos internacionales, así como hechos que derivan de casos resueltos por el Tribunal de Justicia de la Unión Europea y la Corte Europea de Derechos Humanos. Como conclusión, entre otras, se aprecia un comportamiento abiertamente divergente entre los distintos países miembros de la Unión Europea, causado principal pero no exclusivamente por las capacidades y recursos con que cuentan cada uno de ellos.The paper explains the refugee policy of the European Union, describing its elements and most important policy instruments. Then, it describes the difficulties encountered in implementing this policy within member states, using reports from international agencies and facts derived from cases decided by the European Court of Justice and the European Court of Humain Rights. In conclusion, among others, may be mentioned an openly divergent behavior between member states of the European Union, caused mainly but not exclusively, because of the level of skills and resources they have each country

A Novel Radiofluorination Method for the Design of Rhenium(I) PET-Optical Hybrid Nuclear Medicines

Novel fluorine-18 labelled luminescent rhenium tricarbonyl complexes were synthesised to test their utility as agents for position emission tomography (PET) and optical hybrid imaging. These experiments lead to the discovery of a rhenium complexation-dissociation method, which produced never-before-seen radiotracers in substantial radiochemical yields that were unable to be radiosynthesised by traditional means. This method was further applied to the successful production of the Alzheimer’s disease PET imaging nuclear medicine, [18F]CABS13, and new analogues thereof

Mechanochemical Synthesis of Cu2MgSn3S8 and Ag2MgSn3S8

Two new thiospinels of the type AI2BIICIV3SVI8 were successfully synthesized via a mechanochemical route using binary sulfides and sulfur. Cu2MgSn3S8 and Ag2MgSn3S8 are the first AI2BIICIV3SVI8 compounds with magnesium as divalent cation. The crystal structures of Cu2MgSn3S8 and Ag2MgSn3S8 were refined in the cubic space group Fd3m using X‐ray powder diffraction. According to UV/Vis measurements, a direct optical bandgap of ca. 1.65 eV was determined for both Cu2MgSn3S8 and Ag2MgSn3S8. Temperature‐dependent magnetic susceptibility measurements of the Cu2MgSn3S8 sample indicate diamagnetism. A 119Sn Mössbauer spectrum confirms the tetravalent state of tin, underlining the electron‐precise description.TU Berlin, Open-Access-Mittel - 202

Why did distinct types of dual-earner models in Czech, Slovak and East German societies develop and persist?

"Wir untersuchen Arrangements der Aufteilung von Erwerbsarbeit und Kinderbetreuung in Tschechien, der Slowakei und Ostdeutschland, vor und nach 1989. Basierend auf dem institutionalistischen Ansatz untersuchen wir, wie, wann und weshalb sich zwei unterschiedliche Arrangements in dieser Region entwickelt und durchgesetzt haben. Als die Konflikte des modernisierten Gender-Modells offenkundig wurden, schlugen die politischen Entscheidungsträger in der Tschechoslowakei und der DDR verschiedene Pfade ein, um Erwerbsarbeit und Kinderbetreuung in Einklang zu bringen. Infolgedessen entstanden zwischen den Ländern grundlegende Unterschiede in der Kombination von Erwerbsarbeit und Kinderbetreuung und in den damit verbundenen Werten und Normen. Wir erklären ausgehend von der Analyse des institutionellen und kulturellen Erbes dieser Länder, weshalb der Übergang von einem totalitären zu einem demokratischen Gesellschaftstypus mit einem hohen Maß an Kontinuität in den Arrangements der Kombination von Erwerbsarbeit und Kinderbetreuung einherging. Ein zentrales Ergebnis unserer Untersuchung ist, dass neuere Änderungen der institutionellen Rahmenbedingungen der Vereinbarkeit von Beruf und Familie in Tschechien, der Slowakei und in Ostdeutschland nicht auf die massiven Umwälzungen im Zuge des Mauerfalles zurückgehen, sondern in einer Phase relativer Stabilität stattfanden." (Autorenreferat)"We examine pre-1989 and post-1989 work-care models in Czech, Slovak and East German societies. Inspired by the institutionalist approach, we develop a framework that allows to analyze how, when and why two distinct work-care models evolved and persisted in the region. Once problems of the modernized gender model emerged, Czechoslovak and East German governments set the two countries on two distinct work-care policy paths. Consequently, fundamental differences in work-care practices and work-care related values and norms emerged between the two countries. Based on an examination of the institutional and cultural legacy, we explain why the transition from totalitarian to democratic regimes was accompanied by continuity in work-care models rather than radical departures from the previous models. In contrast to traditional institutionalist studies we point out that more recent institutional changes in the sphere of work-care policies in Czech, Slovak and East German societies did not occur as a consequence of the 1989 revolutionary period, but rather evolved in a period of relative stability." (author's abstract

Terrestrial heat flow and an assessment of enhanced geothermal system resources in Minnesota

Low heat flow has been previously reported in Minnesota (406 mW m-2) and the Superior Province of the Canadian Shield (42 ± 8 mW m-2). Low heat flow in Minnesota is due to heat flow measurements made in the mafic rocks of the Mid-Continent Rift System (MCRS) and attributed to the lack of correction for post-glacial climate fluctuations. Radioactivity is a critical heat flow component, particularly in Minnesota where all published heat flow sites are located within the MCRS, creating a bias in the data. The rift is a massive mafic intrusive complex that extends from Moho to the surface, and has characteristically low radioactive heat production. Therefore, there is a sampling problem where heat flow has not been measured in the granitic terranes in Minnesota. Post-glacial climatic fluctuations affect temperature gradients in the upper two kilometers of the crust and are not consistently accounted for in previously published heat flow values. Thermal gradient measurements in Minnesota require re-analysis in order to account for the effects of recent climate change and by post-glacial warming affecting the calculations of heat flow by 25-40%. New heat flow measurements, and the sampling of over two-hundred rock samples, were obtained from cores and outcrops, for 238U, 232Th, and 40K concentrations and thermal conductivity in Minnesota. Several lines of evidence show that steady state heat flow in the region has been underestimated by measurements in shallow boreholes, and geothermal potential in the region is not too low for geothermal development. This study finds the average heat flow in Minnesota to be 44.1±6.6 mW m-2 after corrections for post-glacial warming Newly acquired data from this study on heat flow, thermal conductivity, and radiogenic heat production allows for a re-assessment of the EGS resources at depths of 4 to 10 kilometers for Minnesota. This reassessment determines that EGS resources are available at 6 km than previously at 8.5 kilometers. Total Enhanced Geothermal System (EGS) resources for Minnesota are 98,754 EJ or 18,409 of MWe at a 2% recovery factor. This amount of resources is three times larger than previous estimates by Tester et al. (2006)