POWTEX Neutron Diffractometer at FRM II - new perspectives for in-situ rock deformation analysis

EGU2012-13521 In Geoscience quantitative texture analysis here defined as the quantitative analysis of the crystallographic preferred orientation (CPO), is a common tool for the investigation of fabric development in mono- and polyphase rocks, their deformation histories and kinematics. Bulk texture measurements also allow the quantitative characterisation of the anisotropic physical properties of rock materials. A routine tool to measure bulk sample volumes is neutron texture diffraction, as neutrons have large penetration capabilities of several cm in geological sample materials. The new POWTEX (POWder and TEXture) Diffractometer at the neutron research reactor FRM II in Garching, Germany is designed as a high-intensity diffractometer by groups from the RWTH Aachen, Forschungszentrum Jülich and the University of Göttingen. Complementary to existing neutron diffractometers (SKAT at Dubna, Russia; GEM at ISIS, UK; HIPPO at Los Alamos, USA; D20 at ILL, France; and the local STRESS-SPEC and SPODI at FRM II) the layout of POWTEX is focused on fast time-resolved experiments and the measurement of larger sample series as necessary for the study of large scale geological structures. POWTEX is a dedicated beam line for geoscientific research. Effective texture measurements without sample tilting and rotation are possible firstly by utilizing a range of neutron wavelengths simultaneously (Time-of-Flight technique) and secondly by the high detector coverage (9.8 sr) and a high flux (�~1x10 7 n/cm2s) at the sample. Furthermore the instrument and the angular detector resolution is designed also for strong recrystallisation textures as well as for weak textures of polyphase rocks. These instrument characteristics allow in-situ time-resolved texture measurements during deformation experiments on rocksalt, ice and other materials as large sample environments will be implemented at POWTEX. The in-situ deformation apparatus is operated by a uniaxial spindle drive with a maximum axial load of 250 kN, which will be redesigned to minimize shadowing effects inside the cylindrical detector. The HT deformatione experiments will be carried out in uniaxial compression or extension and an upgrade to triaxial deformation conditions is envisaged. The load frame can alternatively be used for ice deformation by inserting a cryostat cell for temperatures down to 77 K with a triaxial apparatus allowing also simple shear experiments on ice. Strain rates range between 10-8 and 10-3 s-1 reaching to at least 50% axial strain. The deformation apparatus is designed for continuous long-term deformation experiments and can be exchanged between in-situ and ex-situ placements during continuous operation inside and outside the neutron detector

Early life vitamin C deficiency does not alter morphology of hippocampal CA1 pyramidal neurons or markers of synaptic plasticity in a Guinea pig model

Approximately 15% of the Western world population, including pregnant women and their children, is characterized as vitamin C (vitC) deficient. In guinea pigs, early life vitC deficiency causes spatial memory deficits, decreased hippocampal volume and neuron numbers, in otherwise clinically healthy animals. We hypothesized that vitC deficiency leads to decreased brain-derived neurotrophic factor and synaptic plasticity markers in selected brain areas (frontal cortex, hippocampus and striatum) and cause morphological changes in cornu ammonis 1 pyramidal neurons of the hippocampus either through a direct effect or indirectly by increased oxidative stress. Fifty-seven female guinea pigs were allocated to three groups receiving either 1390, 100 or 0–50 mg vitC/kg feed for 11 weeks. Dietary vitC levels were reflected in the plasma, cortical and adrenal gland levels, however, redox imbalance was only present in the adrenal glands allowing for the investigation of a direct influence of vitC deficiency on the chosen parameters in the brain. Synaptic plasticity markers were not affected in the investigated brain areas and no differences in isolated pyramidal neuron morphology was recorded. Based on our findings, it appears that vitC deficiency may primarily elicit impaired neuronal function through increased levels of oxidative stress

Complexity challenges for transition policy: lessons from coastal shipping in Norway

This policy briefing discusses decarbonization policies of “hard-to-abate” sectors, emphasizing the implications of these sectors’ complexity. Specifically, we discuss two sources of complexity: (a) heterogeneity in the form of variation across and within technologies and user segments and (b) interdependencies between technologies (within and between their value chains) and between user segments and adopter groups. Based on research on coastal shipping in Norway, a global frontrunner in decarbonization of this sector, we suggest three guiding principles for developing policy mixes for decarbonizing hard-to-abate sectors: (1) employ technology-specific policies but aim at broad sectoral or general policies when suitable, (2) consider value chain interdependency and user segment heterogeneity when prioritizing technologies and user segments, and (3) translate (rather than transfer) successful policies to other settings (e.g. user segments)

Farlige kryds – afhængig af definitioner og datakilder

Både i Danmark og i udlandet er sammenhængen mellem trafikulykkers sværhedsgrad og frekvens kun dårligt undersøgt. Dette kan skyldes, at der typisk bruges politi­ eller ambulanceregistrerede ulykker, dette giver en skævvridning mod de alvorlige ulykker og en underrepræsentation af de lette ulykker. På Fyns registreres alle henvendelser til skadestuerne detaljeret, når de skyldes en trafikrelateret ulykke. Ved Ulykkes Analyse Gruppen har vi for perioden 1.1.2002 til 1.12.2007 undersøgt alle trafikrelateret ulykker, hvor ulykken er sket i et kryds. Formålet har været at undersøge, om forskellige måder at definere farlige kryds på, leder frem til forskellige grupper af farlige kryds – er det for eksempel de samme kryds der har mange ulykker og alvorlige ulykker. Desuden er det undersøgt, om kryds der er farlige ifølge skadestuernes data også kendes af politiet