43 research outputs found
Stau Search in IceCube
The tau lepton’s supersymmetric partner, the stau, appears in some models as the next-to-lightest supersymmetric particle. Their deacy process into the lightest superpartner is usually suppressed by supersymmetry breaking, which makes it a long-lived particle. In this scenario, its signature is a long, minimally ionizing track when traveling through the IceCube detector. Independent of their primary energy, the stau tracks appear like low-energy muons in the detector. A potential signal of staus would thus be an excess over muon tracks induced by atmospheric muon neutrinos. Our analysis focuses on the region around the horizon as here the ratio between stau signal and atmospheric background is largest. We will present the first sensitivity to constrain the stau mass using IceCube and demonstrate the potential of this analysis with future improvements
D-amphetamine and antipsychotic drug effects on latent inhibition in mice lacking dopamine D2 receptors
Drugs that induce psychosis, such as D-amphetamine (AMP), and those that alleviate it, such as antipsychotics, are suggested to exert behavioral effects via dopamine receptor D2 (D2). All antipsychotic drugs are D2 antagonists, but D2 antagonism underlies the severe and debilitating side effects of these drugs; it is therefore important to know whether D2 is necessary for their behavioral effects. Using D2-null mice (Drd2/), we first investigated whether D2 is required for AMP disruption of latent inhibition (LI). LI is a process of learning to ignore irrelevant stimuli. Disruption of LI by AMP models impaired attention and abnormal salience allocation consequent to dysregulated dopamine relevant to schizophrenia. AMP disruption of LI was seen in both wild-type (WT) and Drd2/. This was in contrast to AMP-induced locomotor hyperactivity, which was reduced in Drd2/. AMP disruption of LI was attenuated in mice lacking dopamine receptor D1 (Drd1/), suggesting that D1 may play a role in AMP disruption of LI. Further supporting this possibility, we found that D1 antagonist SKF83566 attenuated AMP disruption of LI in WT. Remarkably, both haloperidol and clozapine attenuated AMP disruption of LI in Drd2/. This demonstrates that antipsychotic drugs can attenuate AMP disruption of learning to ignore irrelevant stimuli in the absence of D2 receptors. Data suggest that D2 is not essential either for AMP to disrupt or for antipsychotic drugs to reverse AMP disruption of learning to ignore irrelevant stimuli and further that D1 merits investigation in the mediation of AMP disruption of these processes
Klimt artwork: red-pigment material investigation by backscattering Fe-57 Mössbauer spectroscopy, SEM and p-XRF
Material tests were performed on a rediscovered Klimt-artwork “Trompetender Putto”. We performed studies on the red colored spots, mainly taken from non-restored parts. MIMOS II Fe-57 Mössbauer spectroscopy (novelty in art-pigment analysis) mainly reveals haematite and crystallized goethite in red colors. Electron microscopy can identify various layers of the original and overpainting of an artwork. The number of layers fluctuates between three and four chemically painted areas. The portable X-ray fluorescence analysis enables to reduce the pigment list to containing mercury (cinnabar), lead, zinc, iron and titanium. Infrared-light-irradiation visualizes the different age of the pigments
Material erosion, deposition and material transport in the stellarator W7-X
Material erosion, deposition and material transport in the stellaratorW7-XM. Mayera,*, M. Baldena, S. Brezinsekb, V.V. Burwitza,c, C.P. Dhardd, R. Guimarãese, M. Guitart Corominasa, P. Hireta, D. Naujoksd, R. Neua,c, J.H. Schmidt-Denckera, T.S. Silvae, and W7-X TeamaMax-Planck-Institut für Plasmaphysik, Garching, GermanybForschungszentrum Jülich GmbH, Jülich, GermanycTechnische Universität München, München,GermanydMax-Planck-Institut für Plasmaphysik, Greifswald, GermanyeUniversity of São Paulo, São Paulo, BrazilNet erosion, deposition and material transport in the stellarator W7-X were investigated on the Test Divertor Unit (TDU) using special carbon marker coatings and on the vessel walls by analysis of W-coated and regular wall elements duringthe operational phases OP1.2a in the year 2017 and OP1.2b in 2018. While OP1.2a was characterised by high concentrations of oxygen and carbon impuritiesin the plasmas, OP1.2b had much smaller impurity concentrations due to regular boronizations and showed considerably better plasma performances with higher plasma densities. First exposures of tungsten marker coatings in the TDU and at the inner heat shield were performed in OP1.2b. The samples were analysed by quantitative ion beam analysis methods, scanning electron microscopy, and laser-induced breakdown spectroscopy (LIBS).Very high net erosion of carbon was observed at the strike line of all 10 TDUs in both campaignsand is attributed to sputtering and chemical erosion by C and O impurities in OP1.2a[1], while the erosion was probably dominated by impact of H ions in OP1.2b. Re-deposition of carbon in remote areas of the TDU was small.Thicker re-deposited carbon layers with thicknesses of a few microns were observed at the divertor baffles,anoticeable deposition of boron on the TDU was observed after OP1.2b. The inner wall showed no erosion but net deposition of about 100 nm thick boron/carbon layersdue to the boronizations, the outer vessel wall showed a complicated pattern of small erosion areas and thin deposits. Stripes of boron/carbon layers were observed behind the gaps of inner wall protection tiles.The global carbon balance is currently unclear. However, carbon eroded from the TDU was not redeposited in the divertor region but was transported out of the divertor area. Some carbon was redeposited at the divertor baffles but was also pumped out as CO, CO2, or CH4. This is a profound difference to divertors in tokamaks, where eroded material is typically redeposited in remote divertor areas or in the inner divertor. A first assessment of tungsten as plasma-facing material in W7-X is provided.[1] M. Mayer et al., PFMC 2019, Phys. Scr., in press*Corresponding author:tel.: +49 89 3299 1639, e-mail: [email protected]