Measurement of spark probability of GEM detector for CBM muon chamber (MUCH)

The stability of triple GEM detector setups in an environment of high energetic showers is studied. To this end the spark probability in a shower environment is compared to the spark probability in a pion beam.Comment: 5 pages, 10 figure

Chemical effects of diceCT staining protocols on fluid-preserved avian specimens

Diffusible iodine-based contrast-enhanced computed tomography (diceCT) techniques allow visualization of soft tissues of fluid-preserved specimens in three dimensions without dissection or histology. Two popular diceCT stains, iodine-potassium iodide (I2KI) dissolved in water and elemental iodine (I2) dissolved in 100% ethanol (EtOH), yield striking results. Despite the widespread use of these stains in clinical and biological fields, the molecular mechanisms that result in color change and radiopacity attributed to iodine staining are poorly understood. Requests to apply these stains to anatomical specimens preserved in natural history museums are increasing, yet curators have little information about the potential for degradation of treated specimens. To assess the molecular effects of iodine staining on typical museum specimens, we compared the two popular stains and two relatively unexplored stains (I2KI in 70% EtOH, I2 in 70% EtOH). House sparrows (Passer domesticus) were collected and preserved under uniform conditions following standard museum protocols, and each was then subjected to one of the stains. Results show that the three ethanol-based stains worked equally well (producing fully stained, life-like, publication quality scans) but in different timeframes (five, six, or eight weeks). The specimen in I2KI in water became degraded in physical condition, including developing flexible, demineralized bones. The ethanol-based methods also resulted in some demineralization but less than the water-based stain. The pH of the water-based stain was notably acidic compared to the water used as solvent in the stain. Our molecular analyses indicate that whereas none of the stains resulted in unacceptable levels of protein degradation, the bones of a specimen stained with I2KI in water demineralized throughout the staining process. We conclude that staining with I2KI or elemental I2 in 70% EtOH can yield high-quality soft-tissue visualization in a timeframe that is similar to that of better-known iodine-based stains, with lower risk of negative impacts on specimen condition

Analysis of the distal urinary tract in larval and adult zebrafish reveals homology to the human system

Little is known about the distal excretory component of the urinary tract in Danio rerio (zebrafish). This component is affected by many human diseases and disorders of development. Here, we have undertaken multi-level analyses to determine the structure and composition of the distal urinary tract in the zebrafish. In silico searches identified uroplakin 1a (ukp1a), uroplakin 2 (upk2) and uroplakin 3b (upk3b) genes in the zebrafish genome (orthologues to genes that encode urothelium-specific proteins in humans). In situ hybridization demonstrated ukp1a expression in the zebrafish pronephros and cloaca from 96 h post-fertilization. Haematoxylin and Eosin staining of adult zebrafish demonstrated two mesonephric ducts uniting into a urinary bladder that leads to a distinct urethral opening. Immunohistochemistry identified Uroplakin 1a, Uroplakin 2 and GATA3 expression in zebrafish urinary bladder cell layers that match human urothelial expression. Fluorescent dye injections demonstrated zebrafish urinary bladder function, including urine storage and intermittent micturition, and a urethral orifice separate from the larger anal canal and rectum. Our findings reveal homology between the urinary tracts of zebrafish and humans, and offer the former as a model system to study disease

Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR

Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials (mu_B > 500 MeV), effects of chiral symmetry, and the equation-of-state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2022, in the context of the worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal

Understanding Communication of Sustainability Reporting: Application of Symbolic Convergence Theory (SCT)

The purpose of this paper is to investigate the nature of rhetoric and rhetorical strategies that are implicit in the standalone sustainability reporting of the top 24 companies of the Fortune 500 Global. We adopt Bormann’s (Q J Speech 58(4):396–407, 1972) SCT framework to study the rhetorical situation and how corporate sustainability reporting (CSR) messages can be communicated to the audience (public). The SCT concepts in the sustainability reporting’s communication are subject to different types of legitimacy strategies that are used by corporations as a validity and legitimacy claim in the reports. A content analysis has been conducted and structural coding schemes have been developed based on the literature. The schemes are applied to the SCT model which recognizes the symbolic convergent processes of fantasy among communicators in a Society. The study reveals that most of the sample companies communicate fantasy type and rhetorical vision in their corporate sustainability reporting. However, the disclosure or messages are different across locations and other taxonomies of the SCT framework. This study contributes to the current CSR literature about how symbolic or fantasy understandings can be interpreted by the users. It also discusses the persuasion styles that are adopted by the companies for communication purposes. This study is the theoretical extension of the SCT. Researchers may be interested in further investigating other online communication paths, such as human rights reports and director’s reports

Particle identification studies with a full-size 4-GEM prototype for the ALICE TPC upgrade

A large Time Projection Chamber is the main device for tracking and charged-particle identification in the ALICE experiment at the CERN LHC. After the second long shutdown in 2019/20, the LHC will deliver Pb beams colliding at an interaction rate of about 50 kHz, which is about a factor of 50 above the present readout rate of the TPC. This will result in a significant improvement on the sensitivity to rare probes that are considered key observables to characterize the QCD matter created in such collisions. In order to make full use of this luminosity, the currently used gated Multi-Wire Proportional Chambers will be replaced. The upgrade relies on continuously operated readout detectors employing Gas Electron Multiplier technology to retain the performance in terms of particle identification via the measurement of the specific energy loss by ionization d$E$/d$x$. A full-size readout chamber prototype was assembled in 2014 featuring a stack of four GEM foils as an amplification stage. The performance of the prototype was evaluated in a test beam campaign at the CERN PS. The d$E$/d$x$ resolution complies with both the performance of the currently operated MWPC-based readout chambers and the challenging requirements of the ALICE TPC upgrade program. Detailed simulations of the readout system are able to reproduce the data.Comment: Submitted to NIM

The upgrade of the ALICE TPC with GEMs and continuous readout

The upgrade of the ALICE TPC will allow the experiment to cope with the high interaction rates foreseen for the forthcoming Run 3 and Run 4 at the CERN LHC. In this article, we describe the design of new readout chambers and front-end electronics, which are driven by the goals of the experiment. Gas Electron Multiplier (GEM) detectors arranged in stacks containing four GEMs each, and continuous readout electronics based on the SAMPA chip, an ALICE development, are replacing the previous elements. The construction of these new elements, together with their associated quality control procedures, is explained in detail. Finally, the readout chamber and front-end electronics cards replacement, together with the commissioning of the detector prior to installation in the experimental cavern, are presented. After a nine-year period of R&D, construction, and assembly, the upgrade of the TPC was completed in 2020.publishedVersio