249 research outputs found
Performance of the Large-Sized Telescope prototype of the Cherenkov Telescope Array
The next-generation ground-based gamma-ray Cherenkov Telescope Array
Observatory (CTAO) will consist of imaging atmospheric Cherenkov telescopes
(IACTs) of three different sizes distributed in two sites. The Large-Sized
Telescopes will cover the low-energy end of the CTA energy range, starting at
about 20 GeV. After its first years of operation at the CTA northern site, the
Large-Sized Telescope prototype (LST-1) is in the final stage of its
commissioning phase, having collected a significant amount of scientific data
to date.
In this contribution, we present the physics performance of the telescope
using low-zenith Crab Nebula observations and Monte Carlo simulations
fine-tuned accordingly. We show performance figures of merit such as the energy
threshold, effective area, energy and angular resolution, and sensitivity based
on the standard Hillas-parameters approach and following the source-independent
and dependent analysis methods. The analysis threshold is estimated at 30 GeV.
The energy resolution is around 30%, and the angular resolution is 0.3 degrees
at 100 GeV. The best integral sensitivity of LST-1 is about 1.1% of the Crab
Nebula flux above 250 GeV for 50 hours of observations. We also show the
spectral energy distribution and light curve from Crab Nebula observations,
which agree with results from other IACTs and link smoothly with Fermi-LAT when
considering statistical and systematic uncertainties near the energy threshold.Comment: Presented at the 38th International Cosmic Ray Conference (ICRC
2023), 2023 (arXiv:2309.08219
Do fluorescence and transient absorption probe the same intramolecular charge transfer state of 4- ( dimethylamino ) benzonitrile?
We present here the results of time-resolved absorption and emission experiments for 4-(dimethylamino)benzonitrile in solution, which suggest that the fluorescent intramolecular charge transfer (ICT) state may differ from the twisted ICT (TICT) state observed in transient [email protected]
Observation of the hyperfine transition in lithium-like Bismuth : Towards a test of QED in strong magnetic fields
We performed a laser spectroscopic determination of the hyperfine
splitting (HFS) of Li-like and repeated the measurement
of the HFS of H-like . Both ion species were
subsequently stored in the Experimental Storage Ring at the GSI
Helmholtzzentrum f\"ur Schwerionenforschung Darmstadt and cooled with an
electron cooler at a velocity of . Pulsed laser excitation of
the hyperfine-transition was performed in anticollinear and collinear
geometry for and , respectively, and
observed by fluorescence detection. We obtain for , different from the literature
value, and for .
These values provide experimental evidence that a specific difference between
the two splitting energies can be used to test QED calculations in the
strongest static magnetic fields available in the laboratory independent of
nuclear structure effects. The experimental result is in excellent agreement
with the theoretical prediction and confirms the sum of the Dirac term and the
relativistic interelectronic-interaction correction at a level of 0.5%
confirming the importance of accounting for the Breit interaction.Comment: 5 pages, 2 figure
Dual-Phosphorescent Heteroleptic Silver(I) Complex in Long-Lasting Red Light-Emitting Electrochemical Cells
The design of red-emitting silver(I) complexes and their implementation in thin-film lighting are still challenging as (i) their high ligand-field splitting energy leads to high-energy emissions with a controversial mechanism (thermally activated delayed fluorescence vs fluorescence/phosphorescence), and (ii) their low electrochemical stability leads to the formation of silver nanoclusters, limiting device stability to a few seconds. Herein, a thoughtful complex design [Ag(xantphos)(deebq)]PF6 combining a large-bite angle diphosphine ligand (xantphos), a rigid, sterically hindered, π-extended biquinolin (deebq) is reported. In contrast to prior-art, this complex possesses (i) efficient red-emission (λem = 660 nm; photoluminescence quantum yield of 42%) assigned to a thermally equilibrated dual-phosphorescent emission based on spectroscopic/theoretical studies and (ii) stable reduction behavior without forming silver nanoclusters. This results in the first red light-emitting electrochemical cells featuring (i) improved stability of two orders of magnitude compared to prior-art (from seconds to hours) at irradiances of 20 µW cm−2, and (ii) a new degradation mechanism exclusively related to p-doping as confirmed by electrochemical impedance spectroscopy analysis. Indeed, a multi-layered architecture to decouple hole injection/transport and exciton formation enables a further 2-fold enhanced irradiance/stability. Overall, this work illustrates that deciphering the rules for silver(I) complex design for lighting is tricky, but worthwhile.S.L. and L.M.C. contributed equally. R.D.C. acknowledges the European Union's Horizon 2020 research and innovation MSCA-ITN STiBNite No. 956923.Open access funding enabled and organized by Projekt DEAL.Peer reviewe
Proteogenomic characterization of hepatocellular carcinoma
We performed a proteogenomic analysis of hepatocellular carcinomas (HCCs) across clinical stages and etiologies. We identified pathways differentially regulated on the genomic, transcriptomic, proteomic and phosphoproteomic levels. These pathways are involved in the organization of cellular components, cell cycle control, signaling pathways, transcriptional and translational control and metabolism. Analyses of CNA-mRNA and mRNA-protein correlations identified candidate driver genes involved in epithelial-to-mesenchymal transition, the Wnt-β- catenin pathway, transcriptional control, cholesterol biosynthesis and sphingolipid metabolism. The activity of targetable kinases aurora kinase A and CDKs was upregulated. We found that CTNNB1 mutations are associated with altered phosphorylation of proteins involved in actin filament organization, whereas TP53 mutations are associated with elevated CDK1/2/5 activity and altered phosphorylation of proteins involved in lipid and mRNA metabolism. Integrative clustering identified HCC subgroups with distinct regulation of biological processes, metabolic reprogramming and kinase activation. Our analysis provides insights into the molecular processes underlying HCCs
Integrative proteogenomic characterization of hepatocellular carcinoma across etiologies and stages.
Proteogenomic analyses of hepatocellular carcinomas (HCC) have focused on early-stage, HBV-associated HCCs. Here we present an integrated proteogenomic analysis of HCCs across clinical stages and etiologies. Pathways related to cell cycle, transcriptional and translational control, signaling transduction, and metabolism are dysregulated and differentially regulated on the genomic, transcriptomic, proteomic and phosphoproteomic levels. We describe candidate copy number-driven driver genes involved in epithelial-to-mesenchymal transition, the Wnt-β-catenin, AKT/mTOR and Notch pathways, cell cycle and DNA damage regulation. The targetable aurora kinase A and CDKs are upregulated. CTNNB1 and TP53 mutations are associated with altered protein phosphorylation related to actin filament organization and lipid metabolism, respectively. Integrative proteogenomic clusters show that HCC constitutes heterogeneous subgroups with distinct regulation of biological processes, metabolic reprogramming and kinase activation. Our study provides a comprehensive overview of the proteomic and phophoproteomic landscapes of HCCs, revealing the major pathways altered in the (phospho)proteome
Does facial soft tissue protect against zygomatic fractures?: results of a finite element analysis
Introduction: Zygomatic fractures form a major entity in craniomaxillofacial traumatology. Few studies have dealt with biomechanical basics and none with the role of the facial soft tissues. Therefore this study should investigate, whether facial soft tissue plays a protecting role in lateral midfacial trauma
Observations of the Crab Nebula and pulsar with the large-sized telescope prototype of the Cherenkov Telescope Array
Abe et al.The Cherenkov Telescope Array (CTA) is a next-generation ground-based observatory for gamma-ray astronomy at very high energies. The Large-Sized Telescope prototype (LST-1) is located at the CTA-North site, 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 ≃20 GeV. LST-1 started performing astronomical observations in 2019 November, during its commissioning phase, and it has been taking data ever since. We present the first LST-1 observations of the Crab Nebula, the standard candle of very-high-energy gamma-ray astronomy, and use them, together with simulations, to assess the performance of the telescope. LST-1 has reached the expected performance during its commissioning period—only a minor adjustment of the preexisting simulations was needed to match the telescope's behavior. The energy threshold at trigger level is around 20 GeV, rising to ≃30 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 0fdg12–0fdg40, and energy resolution from 15%–50%. Flux sensitivity is around 1.1% of the Crab Nebula flux above 250 GeV for a 50 hr 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.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Fundação de Amparo ä Pesquisa do Estado do Rio de Janeiro (FAPERJ), Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Fundação de Apoio à Ciência, Tecnologia e Inovação do Paraná—Fundação Araucária, Ministry of Science, Technology, Innovations and Communications (MCTIC), Brasil; Ministry of Education and Science, National RI Roadmap Project DO1-153/28.08.2018, Bulgaria; Croatian Science Foundation, Rudjer Boskovic Institute, University of Osijek, University of Rijeka, University of Split, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, University of Zagreb, Faculty of Electrical Engineering and Computing, Croatia; Ministry of Education, Youth and Sports, MEYS LM2015046, LM2018105, LTT17006, EU/MEYS CZ.02.1.01/0.0/0.0/16_013/0001403, CZ.02.1.01/0.0/0.0/18_046/0016007 and CZ.02.1.01/0.0/0.0/16_019/0000754, Czech Republic; CNRS-IN2P3, the French Programme d'investissements d'avenir and the Enigmass Labex, This work has been done thanks to the facilities offered by the Univ. Savoie Mont Blanc—CNRS/IN2P3 MUST computing center, France; Max Planck Society, German Bundesministerium für Bildung und Forschung (Verbundforschung / ErUM), Deutsche Forschungsgemeinschaft (SFBs 876 and 1491), Germany; Istituto Nazionale di Astrofisica (INAF), Istituto Nazionale di Fisica Nucleare (INFN), Italian Ministry for University and Research (MUR); ICRR, University of Tokyo, JSPS, MEXT, Japan; JST SPRING—JPMJSP2108; Narodowe Centrum Nauki, grant No. 2019/34/E/ST9/00224, Poland. The Spanish groups acknowledge the Spanish Ministry of Science and Innovation and the Spanish Research State Agency (AEI) through the government budget lines PGE2021/28.06.000X.411.01, PGE2022/28.06.000X.411.01, and PGE2022/28.06.000X.711.04, and grants PID2022-139117NB-C44, PID2019-104114RB-C31, PID2019-107847RB-C44, PID2019-104114RB-C32, PID2019-105510GB-C31, PID2019-104114RB-C33, PID2019-107847RB-C41, PID2019-107847RB-C43, PID2019-107847RB-C42, PID2019-107988GB-C22, PID2021-124581OB-I00, PID2021-125331NB-I00; the "Centro de Excelencia Severo Ochoa" program through grant Nos. CEX2019-000920-S, CEX2020-001007-S, CEX2021-001131-S; the "Unidad de Excelencia María de Maeztu" program through grant Nos. CEX2019-000918-M, CEX2020-001058-M; the "Ramón y Cajal" program through grants RYC2021-032552-I, RYC2021-032991-I, RYC2020-028639-I, and RYC-2017-22665; the "Juan de la Cierva-Incorporación" program through grant Nos. IJC2018-037195-I and IJC2019-040315-I. They also acknowledge the "Atracción de Talento" program of Comunidad de Madrid through grant No. 2019-T2/TIC-12900; the project "Tecnologiás avanzadas para la exploracioń del universo y sus componentes" (PR47/21 TAU), funded by Comunidad de Madrid, by the Recovery, Transformation and Resilience Plan from the Spanish State, and by NextGenerationEU from the European Union through the Recovery and Resilience Facility; the La Caixa Banking Foundation, grant No. LCF/BQ/PI21/11830030; the "Programa Operativo" FEDER 2014-2020, Consejería de Economía y Conocimiento de la Junta de Andalucía (Ref. 1257737), PAIDI 2020 (Ref. P18-FR-1580) and Universidad de Jaén;"Programa Operativo de Crecimiento Inteligente" FEDER 2014-2020 (Ref. ESFRI-2017-IAC-12), Ministerio de Ciencia e Innovación, 15% co-financed by Consejería de Economía, Industria, Comercio y Conocimiento del Gobierno de Canarias; the "CERCA" program and the grant 2021SGR00426, both funded by the Generalitat de Catalunya; and the European Union's "Horizon 2020" GA:824064 and NextGenerationEU (PRTR-C17.I1). State Secretariat for Education, Research and Innovation (SERI) and Swiss National Science Foundation (SNSF), Switzerland; The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement Nos. 262053 and No 317446. This project is receiving funding from the European Union's Horizon 2020 research and innovation programs under agreement No. 676134. ESCAPE (The European Science Cluster of Astronomy & Particle Physics ESFRI Research Infrastructures) has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No. 824064.With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2019-000920-S).With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2020-001007-S).With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001131-S).With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2019-000918-M).With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2020-001058-M).Peer reviewe
Gammapy: A Python package for gamma-ray astronomy
In this article, we present Gammapy, an open-source Python package for the
analysis of astronomical -ray data, and illustrate the functionalities
of its first long-term-support release, version 1.0. Built on the modern Python
scientific ecosystem, Gammapy provides a uniform platform for reducing and
modeling data from different -ray instruments for many analysis
scenarios. Gammapy complies with several well-established data conventions in
high-energy astrophysics, providing serialized data products that are
interoperable with other software packages. Starting from event lists and
instrument response functions, Gammapy provides functionalities to reduce these
data by binning them in energy and sky coordinates. Several techniques for
background estimation are implemented in the package to handle the residual
hadronic background affecting -ray instruments. After the data are
binned, the flux and morphology of one or more -ray sources can be
estimated using Poisson maximum likelihood fitting and assuming a variety of
spectral, temporal, and spatial models. Estimation of flux points, likelihood
profiles, and light curves is also supported. After describing the structure of
the package, we show, using publicly available -ray data, the
capabilities of Gammapy in multiple traditional and novel -ray analysis
scenarios, such as spectral and spectro-morphological modeling and estimations
of a spectral energy distribution and a light curve. Its flexibility and power
are displayed in a final multi-instrument example, where datasets from
different instruments, at different stages of data reduction, are
simultaneously fitted with an astrophysical flux model.Comment: 26 pages, 16 figure
Convergent genetic and expression data implicate immunity in Alzheimer's disease
Background
Late–onset Alzheimer's disease (AD) is heritable with 20 genes showing genome wide association in the International Genomics of Alzheimer's Project (IGAP). To identify the biology underlying the disease we extended these genetic data in a pathway analysis.
Methods
The ALIGATOR and GSEA algorithms were used in the IGAP data to identify associated functional pathways and correlated gene expression networks in human brain.
Results
ALIGATOR identified an excess of curated biological pathways showing enrichment of association. Enriched areas of biology included the immune response (p = 3.27×10-12 after multiple testing correction for pathways), regulation of endocytosis (p = 1.31×10-11), cholesterol transport (p = 2.96 × 10-9) and proteasome-ubiquitin activity (p = 1.34×10-6). Correlated gene expression analysis identified four significant network modules, all related to the immune response (corrected p 0.002 – 0.05).
Conclusions
The immune response, regulation of endocytosis, cholesterol transport and protein ubiquitination represent prime targets for AD therapeutics
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