70 research outputs found
Observations of the Crab Nebula and Pulsar with the Large-Sized Telescope Prototype of the Cherenkov Telescope Array
CTA (Cherenkov Telescope Array) is the next generation ground-based
observatory for gamma-ray astronomy at very-high energies. The Large-Sized
Telescope prototype (\LST{}) is located at the Northern site of CTA, on the
Canary Island of La Palma. LSTs are designed to provide optimal performance in
the lowest part of the energy range covered by CTA, down to GeV.
\LST{} started performing astronomical observations in November 2019, during
its commissioning phase, and it has been taking data since then. We present the
first \LST{} observations of the Crab Nebula, the standard candle of very-high
energy gamma-ray astronomy, and use them, together with simulations, to assess
the basic performance parameters of the telescope. The data sample consists of
around 36 hours of observations at low zenith angles collected between November
2020 and March 2022. \LST{} has reached the expected performance during its
commissioning period - only a minor adjustment of the preexisting simulations
was needed to match the telescope behavior. The energy threshold at trigger
level is estimated to be around 20 GeV, rising to GeV after data
analysis. Performance parameters depend strongly on energy, and on the strength
of the gamma-ray selection cuts in the analysis: angular resolution ranges from
0.12 to 0.40 degrees, and energy resolution from 15 to 50\%. Flux sensitivity
is around 1.1\% of the Crab Nebula flux above 250 GeV for a 50-h observation
(12\% for 30 minutes). The spectral energy distribution (in the 0.03 - 30 TeV
range) and the light curve obtained for the Crab Nebula agree with previous
measurements, considering statistical and systematic uncertainties. A clear
periodic signal is also detected from the pulsar at the center of the Nebula.Comment: Submitted to Ap
Anaerobic Alcohol Conversion to Carbonyl Compounds over Nanoscaled Rh-Doped SrTiO3 under Visible Light
Photocatalytic oxidation of organic compounds on semiconductors provides a mild approach for organic synthesis and solar energy utilization. Herein, we identify the key points for the photocatalytic oxidation over Pt-loaded Rh-doped strontium titanate allowing the conversion of alcohols efficiently and selectively to aldehydes and ketones under anaerobic conditions and visible light with an apparent quantum efficiency of pure benzyl alcohol oxidation at 420 nm of <= 49.5%. Mechanistic investigations suggest that thermodynamically the controlled valence band edge position via Rh doping provides a suitable oxidation ability of photogenerated holes, avoiding the powerful hydroxyl radical intermediates prone to overoxidation resulting in high selectivity. Kinetically, oxygen vacancies induced by Rh3+ substitution in the SrTiO3 lattice not only favor the dissociative adsorption of alcohols yielding alkoxy species but also induce the weakening of the alpha-C-H bond facilitating its cleavage by the photogenerated holes. Pt nanoparticles deposited as a cocatalyst contribute to the final hydrogen evolution
Cost-optimal design and automated production of sandwich structures for wind turbine rotor blades
The publicly funded research project BladeMaker aims at industrializing the production of wind turbine rotor blades to achieve a reproducible high quality and cost reductions. Along with other processes it addresses the automated production of sandwich structures through an in-situ foaming process of the core. For the skins, two alternative processes are presented: two-sided infusion of dry non-crimp fabrics and automated tape laying of prepreg tapes. Manual lay-up of pre-manufactured PVC foam kits is replaced by an automated application of liquid, in-situ expanding polyurethane (PU) foam directly into the mold. The benefits are considerably lower material costs, easier material transportation and the reduction of scrap. This innovative process also brings new challenges in terms of material performance and structural design, since the density-specific material properties of PUs are in general lower than of the typically used PVC-foams. Material properties of PUs depend on the selection of the specific PU system as well as on foaming parameters and especially on the density. A parameter study for a representative sandwich element has been carried out to make a trade-off between structural performance, weight and costs. Assuming that global buckling of the sandwich plate and skin wrinkling of the sandwich skins are the two dimensioning failure modes, the critical loads were calculated for different core thicknesses and PU densities. The main requirement was to achieve at least the same critical load with a PU-sandwich as with the PVC-sandwich. Finally, the material costs and the structural mass were evaluated to determine the cheapest and the lightest configuration. The contribution of additional flow meshes and resin uptake of the core material was taken into account. Results for the representative sandwich element show that the mass difference is small and that PU sandwich structures allow for significant cost reductions
The dark matter of the cancer genome: aberrations in regulatory elements, untranslated regions, splice sites, non-coding RNA and synonymous mutations
This paper deals with the use of reported speech (RS) in Spanish criminal lawsuits (querellas) and police reports (denuncias) and argues about the most suitable strategies to translate such RS into Italian. In line of principle, the written record of the statements made by the individual(s) who filed the complaint is often the result of an oral cooperation between the plaintiff and the police officer and/or their attorney, whose subjectivity is reflected on the texts in a quite different fashion in the two legal cultures. The so-called âverbatim assumptionâ of quotations in direct speech (DS) turns out to be a fallacy in the discussed genres, insofar as the locutor (i.e. the police officer or the attorney responsible for the drafting of the document) often normalizes the original utterances of the enunciator (i.e. the plaintiff whose point of view is represented in the report) in terms of cohesion, register and sentence length.
Usually, these texts are translated following a strictly âinterlinear approachâ, so much so as to result almost illegible. An adequate command of genre conventions â both in the source and in the target language â and the abidance by the translation universals of simplification and explicitation may help the translator produce a more efficient and readable target text, consistent with the expectations of a jurist in the target culture
Kommunikation fĂŒr Nonprofit-Organisationen
Nonprofit-Organisation weisen im Vergleich zu kommerziellen Unternehmen einige Besonderheiten auf. Dies hat wiederum Auswirkungen auf die Kommunikationspolitik fĂŒr Nonprofit-Unternehmen. Der Beitrag setzt an diesem Punkt an und gibt zunĂ€chst einen Ăberblick ĂŒber die Herausforderungen, Ziele und Aufgaben der Kommunikationspolitik im Nonprofit-Bereich. AnschlieĂend liegt der Fokus auf der strategischen Kommunikationsplanung. Im Rahmen der operativen Kommunikationsplanung wird schlieĂlich aufgezeigt, welche Kommunikationsinstrumente fĂŒr Nonprofit-Organisation besonders geeignet sind
The dark matter of the cancer genome: aberrations in regulatory elements, untranslated regions, splice sites, non-coding RNA and synonymous mutations
Cancer is a disease of the genome caused by oncogene activation and tumor suppressor gene inhibition. Deep sequencing studies including large consortia such as TCGA and ICGC identified numerous tumorâspecific mutations not only in proteinâcoding sequences but also in nonâcoding sequences. Although 98% of the genome is not translated into proteins, most studies have neglected the information hidden in this âdark matterâ of the genome. Malignancyâdriving mutations can occur in all genetic elements outside the coding region, namely in enhancer, silencer, insulator, and promoter as well as in 5âČâUTR and 3âČâUTR. Intron or splice site mutations can alter the splicing pattern. Moreover, cancer genomes contain mutations within nonâcoding RNA, such as microRNA, lncRNA, and lincRNA. A synonymous mutation changes the coding region in the DNA and RNA but not the protein sequence. Importantly, oncogenes such as TERT or miRâ21 as well as tumor suppressor genes such as TP53/p53,APC,BRCA1, or RB1 can be affected by these alterations. In summary, codingâindependent mutations can affect gene regulation from transcription, splicing, mRNA stability to translation, and hence, this largely neglected area needs functional studies to elucidate the mechanisms underlying tumorigenesis. This review will focus on the important role and novel mechanisms of these nonâcoding or allegedly silent mutations in tumorigenesis
- âŠ