In situ estimation of ice crystal properties at the South Pole using LED calibration data from the IceCube Neutrino Observatory

The IceCube Neutrino Observatory instruments about 1ĝ€¯km3 of deep, glacial ice at the geographic South Pole. It uses 5160 photomultipliers to detect Cherenkov light emitted by charged relativistic particles. An unexpected light propagation effect observed by the experiment is an anisotropic attenuation, which is aligned with the local flow direction of the ice. We examine birefringent light propagation through the polycrystalline ice microstructure as a possible explanation for this effect. The predictions of a first-principles model developed for this purpose, in particular curved light trajectories resulting from asymmetric diffusion, provide a qualitatively good match to the main features of the data. This in turn allows us to deduce ice crystal properties. Since the wavelength of the detected light is short compared to the crystal size, these crystal properties include not only the crystal orientation fabric, but also the average crystal size and shape, as a function of depth. By adding small empirical corrections to this first-principles model, a quantitatively accurate description of the optical properties of the IceCube glacial ice is obtained. In this paper, we present the experimental signature of ice optical anisotropy observed in IceCube light-emitting diode (LED) calibration data, the theory and parameterization of the birefringence effect, the fitting procedures of these parameterizations to experimental data, and the inferred crystal properties

WegE – Wegweisende Lehrerbildung II – Schlussbericht

Im Zentrum des Bamberger Projekts WegE (Wegweisende Lehrerbildung) stand die Weiterentwicklung der Kommunikation und Zusammenarbeit zwischen Wissenschaften, Fachdidaktiken und Schulpraxis. Basierend auf Ergebnissen aus WegE I wurden (1) fachliche Perspektiven zur kulturbezogenen Bildung (KulturPLUS) vernetzt; (2) Ausbildungsteile über Fächergrenzen hinweg verbunden (BilVer); (3) die Kooperation mit Schulen durch ein Kompetenzzentrum für Beratung gestärkt (BERA); und (4) die Lehrämter „Berufliche Bildung“ in Sozial- und Wirtschaftspädagogik profiliert (BeBi). Drei neue Querschnittsthemen setzten inhaltliche Akzente: (a) Der Umgang mit Digitalisierung in der Lehrkräftebildung (DigiLeb) wurde durch Fortbildung der Universitätsdozierenden und die Entwicklung von Lerntools wie einem E-Portfolio umgesetzt. (b) Die Professionalisierung bezüglich Heterogenität in Schulen (ProHet) wurde durch die Weiterentwicklung der Lehre und Fokussierung auf Inklusion und Diversität gestärkt. (c) Das dritte Querschnittsthema (SchulPrax) konzentrierte sich auf die Kohärenz der praktischen Studien und den Kontakt mit Praktikumslehrkräften. Alle Maßnahmen wurden evaluiert, um die evidenzbasierte Qualitätssicherung der Lehrerbildung auszubauen. Eine Matrixstruktur sicherte den Austausch spezifischer Expertise. Unser Ziel war eine regional verankerte, global orientierte Lehrkräftebildung, die angehende Lehrkräfte kompetenzorientiert auf ihre zukünftigen Herausforderungen vorbereitet und sie befähigt, Entwicklungsprozesse aktiv zu gestalten. Datei-Upload durch TIBThe Bamberg project WegE (Wegweisende Lehrerbildung) focused on the further development of communication and cooperation between the sciences, subject didactics and school practice. Based on the results of WegE I, (1) subject-specific perspectives on culture-related education (KulturPLUS) were networked; (2) educational science training components were linked across subject boundaries (BilVer); (3) cooperation with schools was strengthened through a competence center for counseling (BERA); and (4) the “vocational education” teaching specializations in social and business education were profiled (BeBi). Three new cross-cutting topics set the tone in terms of content: (a) Dealing with digitalization in teacher training (DigiLeb) was implemented through further training for university lecturers and the development of learning tools such as an e-portfolio. (b) Professionalization with regard to heterogeneity in schools (ProHet) was strengthened through the further development of teaching and a focus on inclusion and diversity. (c) The third cross-cutting theme (SchulPrax) focused on the coherence of practical studies and contact with trainee teachers. All measures were evaluated in order to expand the evidence-based quality assurance of teacher training. A matrix structure ensured the exchange of specific expertise. Our goal was a regionally anchored, globally oriented teacher training program that prepares prospective teachers for their future challenges in a skills-oriented manner and enables them to actively shape development processes

In situ estimation of ice crystal properties at the South Pole using LED calibration data from the IceCube Neutrino Observatory

The IceCube Neutrino Observatory instruments about 1 km3 of deep, glacial ice at the geographic South Pole. It uses 5160 photomultipliers to detect Cherenkov light emitted by charged relativistic particles. An unexpected light propagation effect observed by the experiment is an anisotropic attenuation, which is aligned with the local flow direction of the ice. We examine birefringent light propaga- tion through the polycrystalline ice microstructure as a pos- sible explanation for this effect. The predictions of a first- principles model developed for this purpose, in particular curved light trajectories resulting from asymmetric diffusion, provide a qualitatively good match to the main features of the data. This in turn allows us to deduce ice crystal properties. Since the wavelength of the detected light is short compared to the crystal size, these crystal properties include not only the crystal orientation fabric, but also the average crystal size and shape, as a function of depth. By adding small empiri- cal corrections to this first-principles model, a quantitatively accurate description of the optical properties of the IceCube glacial ice is obtained. In this paper, we present the exper- imental signature of ice optical anisotropy observed in Ice- Cube light-emitting diode (LED) calibration data, the theory and parameterization of the birefringence effect, the fitting procedures of these parameterizations to experimental data, and the inferred crystal propertie

Design and Performance of the mDOM Mainboard for the IceCube Upgrade

About 400 mDOMs (multi-PMT Digital Optical Modules) will be deployed as part of the IceCube Upgrade Project. The mDOM’s high pressure-resistant glass sphere houses 24 PMTs, 3 cameras, 10 flasher LEDs and various sensors. The mDOM mainboard design was challenging due to the limited available volume and demanding engineering requirements, like the maximum overall power consumption, a minimum trigger threshold of 0.2 photoelectrons (PE), the dynamic range and the linearity requirements. Another challenge was the FPGA firmware design, dealing with about 35 Gbit/s of continuous ADC data from the digitization of the 24 PMT channels, the control of a high speed dynamic buffer and the discriminator output sampling rate of about 1GSPS. High-speed sampling of each of the discriminator outputs at ~1 GSPS improves the leading-edge time resolution for the PMT waveforms. An MCU (microcontroller unit) coordinates the data taking, the data exchange with the surface and the sensor readout. Both the FPGA firmware and MCU software can be updated remotely. After discussing the main hardware blocks and the analog frontend (AFE) design, test results will be shown, covering especially the AFE performance. Additionally, the functionality of various sensors and modules will be evaluated

In situ estimation of ice crystal properties at the South Pole using LED calibration data from the IceCube Neutrino Observatory

The IceCube Neutrino Observatory instruments about 1 km3 of deep, glacial ice at the geographic South Pole. It uses 5160 photomultipliers to detect Cherenkov light emitted by charged relativistic particles. An unexpected light propagation effect observed by the experiment is an anisotropic attenuation, which is aligned with the local flow direction of the ice. We examine birefringent light propagation through the polycrystalline ice microstructure as a possible explanation for this effect. The predictions of a first-principles model developed for this purpose, in particular curved light trajectories resulting from asymmetric diffusion, provide a qualitatively good match to the main features of the data. This in turn allows us to deduce ice crystal properties. Since the wavelength of the detected light is short compared to the crystal size, these crystal properties include not only the crystal orientation fabric, but also the average crystal size and shape, as a function of depth. By adding small empirical corrections to this first-principles model, a quantitatively accurate description of the optical properties of the IceCube glacial ice is obtained. In this paper, we present the experimental signature of ice optical anisotropy observed in IceCube light-emitting diode (LED) calibration data, the theory and parameterization of the birefringence effect, the fitting procedures of these parameterizations to experimental data, and the inferred crystal properties.Peer Reviewe

In-situ estimation of ice crystal properties at the South Pole using LED calibration data from the IceCube Neutrino Observatory

The IceCube Neutrino Observatory instruments about 1 km3 of deep, glacial ice at the geographic South Pole using 5160 photomultipliers to detect Cherenkov light emitted by charged relativistic particles. A unexpected light propagation effect observed by the experiment is an anisotropic attenuation, which is aligned with the local flow direction of the ice. Birefringent light propagation has been examined as a possible explanation for this effect. The predictions of a first-principles birefringence model developed for this purpose, in particular curved light trajectories resulting from asymmetric diffusion, provide a qualitatively good match to the main features of the data. This in turn allows us to deduce ice crystal properties. Since the wavelength of the detected light is short compared to the crystal size, these crystal properties do not only include the crystal orientation fabric, but also the average crystal size and shape, as a function of depth. By adding small empirical corrections to this first-principles model, a quantitatively accurate description of the optical properties of the IceCube glacial ice is obtained. In this paper, we present the experimental signature of ice optical anisotropy observed in IceCube LED calibration data, the theory and parametrization of the birefringence effect, the fitting procedures of these parameterizations to experimental data as well as the inferred crystal properties.</p

Tetrathiomolybdate Causes Formation of Hepatic Copper−Molybdenum Clusters in an Animal Model of Wilson's Disease

Wilson's disease is an autosomal recessive human illness in which large quantities of copper accumulate in various organs, including the brain and the liver. If left untreated, it results in hepatitis, neurological complications, and death. Long-Evans Cinnamon (LEC) rats have a homologous mutation to Wilson's disease and thus provide an animal model. Liver lysosomes from tetrathiomolybdate-treated LEC rats were isolated and analyzed by Cu and Mo K-edge X-ray absorption spectroscopy. The lysosomes contained a Cu−Mo−S cluster in which the Mo is coordinated by four sulfurs at 2.24 Å with approximately three copper neighbors at 2.70 Å. Each Cu is coordinated to 3−4 sulfurs at 2.28 Å with approximately one Mo neighbor at 2.70 Å. These results indicate the formation of a biologically novel molybdenum−copper−sulfur cluster