186 research outputs found
Background Simulations of the Wide Field Imager of the ATHENA X-Ray Observatory
The ATHENA X-ray Observatory-IXO is a planned multinational orbiting X-ray
observatory with a focal length of 11.5m. ATHENA aims to perform pointed
observations in an energy range from 0.1 keV to 15 keV with high sensitivity.
For high spatial and timing resolution imaging and spectroscopic observations
the 640x640 pixel^2 large DePFET-technology based Wide field Imager (WFI) focal
plane detector, providing a field of view of 18 arcsec will be the main
detector. Based on the actual mechanics, thermal and shielding design we
present estimates for the WFI cosmic ray induced background obtained by the use
of Monte-Carlo simulations and possible background reduction measures.Comment: IEEE NSS MIC Conference 2011, Valencia, Spai
Photoacoustic hygrometer for icing wind tunnel water content measurement: design, analysis and intercomparison
This work describes the latest design, calibration and application of a near-infrared laser diode-based photoacoustic (PA) hygrometer developed for total water content measurement in simulated atmospheric freezing precipitation and high ice water content conditions with relevance in fundamental icing research, aviation testing, and certification. The single-wavelength and single-pass PA absorption cell is calibrated for molar water vapor fractions with a two-pressure humidity generator integrated into the instrument. Laboratory calibration showed an estimated measurement accuracy better than 3.3â% in the water vapor mole fraction range of 510â12â360âppm (5â% from 250â21â200âppm) with a theoretical limit of detection (3Ï) of 3.2âppm. The hygrometer is examined in combination with a basic isokinetic evaporator probe (IKP) and sampling system designed for icing wind tunnel applications, for which a general description of total condensed water content (CWC) measurements and uncertainties are presented. Despite the current limitation of the IKP to a hydrometeor mass flux below 90âgm-2s, a CWC measurement accuracy better than 20â% is achieved by the instrument above a CWC of 0.14âgâmâ3 in cold air (â30ââC) with suitable background humidity measurement. Results of a comparison to the Cranfield University IKP instrument in freezing drizzle and rain show a CWC agreement of the two instruments within 20â%, which demonstrates the potential of PA hygrometers for water content measurement in atmospheric icing condition
Patterns of tumor infiltrating lymphocytes in adenoid cystic carcinoma of the head and neck
Adenoid cystic carcinoma (ACC) is a rare malignancy in the head and neck. The prognosis remains poor and late recurrences often occur after 5 years and later. To date, there are no reliable prognostic markers for ACC. In several solid tumors, tertiary lymphoid structures (TLS) are associated with improved survival. This study aims to investigate the role of distribution patterns of tumor infiltrating immune cells (TIL) in ACC. A cohort of 50 patients from three different cancer centers was available for analysis. Sections were stained for CD3, CD4, CD8 and CD20 and evaluated with regard to their distribution of TIL. Patterns were determined as infiltrated-excluded, infiltrated-inflamed and presence of tertiary lymphoid structures. About half of the cases showed an infiltrated-excluded TIL pattern and only a minority of six cases had TLS present within the tumor. Within the inflamed phenotype CD3+ cells were by far the most abundant lymphocyte subtype, and within this compartment, CD8+ T cells were predominant. There was no influence on overall or disease-free survival by any of the TIL patterns. This indicates that ACC is a tumor with very low immunogenicity and even abundance of lymphocytes does not seem to improve prognosis for this disease. Therefore, the observed lack of response towards immunotherapy is not surprising and other methods to induce recognition of ACC by the immune system must be found
The VLA-COSMOS 3 GHz Large Project : Evolution of Specific Star Formation Rates out to z similar to 5
We provide a coherent, uniform measurement of the evolution of the logarithmic star formation rate (SFR)-stellar mass (M-*) relation, called the main sequence (MS) of star-forming galaxies, for star-forming and all galaxies out to z similar to 5. We measure the MS using mean stacks of 3 GHz radio-continuum images to derive average SFRs for similar to 200,000 mass-selected galaxies at z > 0.3 in the COSMOS field. We describe the MS relation by adopting a new model that incorporates a linear relation at low stellar mass (log(M-*/M-circle dot) <10) and a flattening at high stellar mass that becomes more prominent at low redshift (z <1.5). We find that the SFR density peaks at 1.5 <z <2, and at each epoch there is a characteristic stellar mass (M-* = 1-4 x 10(10)M(circle dot)) that contributes the most to the overall SFR density. This characteristic mass increases with redshift, at least to z similar to 2.5. We find no significant evidence for variations in the MS relation for galaxies in different environments traced by the galaxy number density at 0.3 <z <3, nor for galaxies in X-ray groups at z similar to 0.75. We confirm that massive bulge-dominated galaxies have lower SFRs than disk-dominated galaxies at a fixed stellar mass at z <1.2. As a consequence, the increase in bulge-dominated galaxies in the local star-forming population leads to a flattening of the MS at high stellar masses. This indicates that "mass quenching" is linked with changes in the morphological composition of galaxies at a fixed stellar mass.Peer reviewe
The lifecycle of molecular clouds in nearby star-forming disc galaxies
It remains a major challenge to derive a theory of cloud-scale (â âČ100âpc) star formation and feedback, describing how galaxies convert gas into stars as a function of the galactic environment. Progress has been hampered by a lack of robust empirical constraints on the giant molecular cloud (GMC) lifecycle. We address this problem by systematically applying a new statistical method for measuring the evolutionary timeline of the GMC lifecycle, star formation, and feedback to a sample of nine nearby disc galaxies, observed as part of the PHANGS-ALMA survey. We measure the spatially resolved (âŒ100âpc) CO-to-Hâα flux ratio and find a universal de-correlation between molecular gas and young stars on GMC scales, allowing us to quantify the underlying evolutionary timeline. GMC lifetimes are short, typically 10â30Myrâ , and exhibit environmental variation, between and within galaxies. At kpc-scale molecular gas surface densities ÎŁH2â„8Mâpcâ2â , the GMC lifetime correlates with time-scales for galactic dynamical processes, whereas at ÎŁH2â€8Mâpcâ2 GMCs decouple from galactic dynamics and live for an internal dynamical time-scale. After a long inert phase without massive star formation traced by Hâα (75-90 perâcent of the cloud lifetime), GMCs disperse within just 1â5Myr once massive stars emerge. The dispersal is most likely due to early stellar feedback, causing GMCs to achieve integrated star formation efficiencies of 4-10 perâcent. These results show that galactic star formation is governed by cloud-scale, environmentally dependent, dynamical processes driving rapid evolutionary cycling. GMCs and HâII regions are the fundamental units undergoing these lifecycles, with mean separations of 100â300pc in star-forming discs. Future work should characterize the multiscale physics and mass flows driving these lifecycles.MC and JMDK gratefully acknowledge funding
from the Deutsche Forschungsgemeinschaft (DFG, German
Research Foundation) through an Emmy Noether Research Group
(grant number KR4801/1-1) and the DFG Sachbeihilfe (grant
number KR4801/2-1). JMDK, APSH, SMRJ, and DTH gratefully
acknowledge funding from the European Research Council
(ERC) under the European Unionâs Horizon 2020 research and
innovation programme via the ERC Starting Grant MUSTANG
(grant agreement number 714907). MC, JMDK, SMRJ, and DTH
acknowledge support from the Australia-Germany Joint Research
Cooperation Scheme (UA-DAAD, grant number 57387355).
APSH, SMRJ, and DTH are fellows of the International Max
Planck Research School for Astronomy and Cosmic Physics
at the University of Heidelberg (IMPRS-HD). BG gratefully
acknowledges the support of the Australian Research Council
as the recipient of a Future Fellowship (FT140101202). CNC,
AH, and JP acknowledge funding from the Programme National
âPhysique et Chimie du Milieu Interstellaireâ (PCMI) of the Centre
national de la recherche scientifique/Institut national des sciences
de lâUnivers (CNRS/INSU) with the Institut de Chimie/Institut de
Physique (INC/INP), co-funded by the Commissariat a lâ ` energie ÂŽ
atomique et aux energies alternatives (CEA) and the Centre ÂŽ
national dâetudes spatiales (CNES). AH acknowledges support ÂŽ
by the Programme National Cosmology et Galaxies (PNCG) of
CNRS/INSU with the INP and the Institut national de physique
nucleaire et de physique des particules (IN2P3), co-funded by ÂŽ
CEA and CNES. PL, ES, CF, DL, and TS acknowledge funding
from the ERC under the European Unionâs Horizon 2020 research
and innovation programme (grant agreement No. 694343).
The work of AKL, JS, and DU is partially supported by the
National Science Foundation (NSF) under Grants No. 1615105,
1615109, and 1653300. AKL also acknowledges partial support
from the National Aeronautics and Space Administration
(NASA) Astrophysics Data Analysis Program (ADAP) grants
NNX16AF48G and NNX17AF39G. ER acknowledges the support
of the Natural Sciences and Engineering Research Council of
Canada (NSERC), funding reference number RGPIN-2017-03987.
FB acknowledges funding from the ERC under the European
Unionâs Horizon 2020 research and innovation programme (grant
agreement No. 726384). GB is supported by the Fondo de Fomento
al Desarrollo CientŽıfico y Tecnologico of the Comisi Ž on Nacional de Ž
Investigacion Cient Ž Žıfica y Tecnologica (CONICYT/FONDECYT), Ž
Programa de Iniciacion, Folio 11150220. SCOG acknowledges ÂŽ
support from the DFG via SFB 881 âThe Milky Way Systemâ
(subprojects B1, B2, and B8) and also via Germanyâs
Excellence Strategy EXC-2181/1â390900948 (the Heidelberg
STRUCTURES Excellence Cluster). KK gratefully acknowledges
funding from the DFG in the form of an Emmy Noether
Research Group (grant number KR4598/2-1, PI Kreckel). AU
acknowledges support from the Spanish funding grants AYA2016-79006-P (MINECO/FEDER) and PGC2018-094671-B-I00
(MCIU/AEI/FEDER)
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Impact of Right Ventricular Performance in Patients Undergoing Extracorporeal Membrane Oxygenation Following Cardiac Surgery
Background: Extracorporeal membrane oxygenation following cardiac surgery safeguards endâorgan oxygenation but unfavorably alters cardiac hemodynamics. Along with the detrimental effects of cardiac surgery to the right heart, this might impact outcome, particularly in patients with preexisting right ventricular (RV) dysfunction. We sought to determine the prognostic impact of RV function and to improve established riskâprediction models in this vulnerable patient cohort. Methods and Results: Of 240 patients undergoing extracorporeal membrane oxygenation support following cardiac surgery, 111 had echocardiographic examinations at our institution before implantation of extracorporeal membrane oxygenation and were thus included. Median age was 67 years (interquartile range 60â74), and 74 patients were male. During a median followâup of 27 months (interquartile range 16â63), 75 patients died. Fiftyâone patients died within 30 days, 75 during longâterm followâup (median followâup 27 months, minimum 5 months, maximum 125 months). Metrics of RV function were the strongest predictors of outcome, even stronger than left ventricular function (P<0.001 for receiver operating characteristics comparisons). Specifically, RV freeâwall strain was a powerful predictor univariately and after adjustment for clinical variables, Simplified Acute Physiology Scoreâ3, tricuspid regurgitation, surgery type and duration with adjusted hazard ratios of 0.41 (95%CI 0.24â0.68; P=0.001) for 30âday mortality and 0.48 (95%CI 0.33â0.71; P<0.001) for longâterm mortality for a 1âSD (SD=â6%) change in RV freeâwall strain. Combined assessment of the additive EuroSCORE and RV freeâwall strain improved risk classification by a net reclassification improvement of 57% for 30âday mortality (P=0.01) and 56% for longâterm mortality (P=0.02) compared with the additive EuroSCORE alone. Conclusions: RV function is strongly linked to mortality, even after adjustment for baseline variables and clinical risk scores. RV performance improves established risk prediction models for shortâ and longâterm mortality
Evaluation of radio-immunotherapy sequence on immunological responses and clinical outcomes in patients with melanoma brain metastases (ELEKTRA)
In patients with melanoma brain metastases (MBM), a combination of radiotherapy (RT) with immune checkpoint inhibitors (ICI) is routinely used. However, the best sequence of radio-immunotherapy (RIT) remains unclear. In an exploratory phase 2 trial, MBM patients received RT (stereotactic or whole-brain radiotherapy depending on the number of MBM) combined with ipilimumab (ipi) ± nivolumab (nivo) in different sequencing (Rad-ICI or ICI-Rad). Comparators arms included patients treated with ipi-free systemic treatment or without RT (in MBM-free patients). The primary endpoints were radiological and immunological responses in the peripheral blood. Secondary endpoints were progression-free survival (PFS) and overall survival (OS). Of 106 screened, 92 patients were included in the study. Multivariate analysis revealed an advantage for patients starting with RT (Rad-ICI) for overall response rate (RR: p = .007; HR: 7.88 (95%CI: 1.76-35.27)) and disease control rate (DCR: p = .036; HR: 6.26 (95%CI: 1.13-34.71)) with a trend for a better PFS (p = .162; HR: 1.64 (95%CI: 0.8-3.3)). After RT plus two cycles of ipi-based ICI in both RIT sequences, increased frequencies of activated CD4, CD8 T cells and an increase in melanoma-specific T cell responses were observed in the peripheral blood. Lasso regression analysis revealed a significant clinical benefit for patients treated with Rad-ICI sequence and immunological features, including high frequencies of memory T cells and activated CD8 T cells in the blood. This study supports increasing evidence that sequencing RT followed by ICI treatment may have better effects on the immunological responses and clinical outcomes in MBM patients
The lifecycle of molecular clouds in nearby star-forming disc galaxies
It remains a major challenge to derive a theory of cloud-scale (â âČ100âpc) star formation and feedback, describing how galaxies convert gas into stars as a function of the galactic environment. Progress has been hampered by a lack of robust empirical constraints on the giant molecular cloud (GMC) lifecycle. We address this problem by systematically applying a new statistical method for measuring the evolutionary timeline of the GMC lifecycle, star formation, and feedback to a sample of nine nearby disc galaxies, observed as part of the PHANGS-ALMA survey. We measure the spatially resolved (âŒ100âpc) CO-to-Hâα flux ratio and find a universal de-correlation between molecular gas and young stars on GMC scales, allowing us to quantify the underlying evolutionary timeline. GMC lifetimes are short, typically 10â30 Myrâ , and exhibit environmental variation, between and within galaxies. At kpc-scale molecular gas surface densities ÎŁ_(Hâ) â„ 8 M_â pcâ»ÂČâ , the GMC lifetime correlates with time-scales for galactic dynamical processes, whereas at ÎŁ_(Hâ) †8 M_â pcâ»ÂČ GMCs decouple from galactic dynamics and live for an internal dynamical time-scale. After a long inert phase without massive star formation traced by Hâα (75â90 perâcent of the cloud lifetime), GMCs disperse within just 1â5 Myr once massive stars emerge. The dispersal is most likely due to early stellar feedback, causing GMCs to achieve integrated star formation efficiencies of 4â10 perâcent. These results show that galactic star formation is governed by cloud-scale, environmentally dependent, dynamical processes driving rapid evolutionary cycling. GMCs and HâII regions are the fundamental units undergoing these lifecycles, with mean separations of 100â300 pc in star-forming discs. Future work should characterize the multiscale physics and mass flows driving these lifecycles
The VLA-COSMOS 3 GHz Large Project: Evolution of Specific Star Formation Rates out to z ~ 5
We provide a coherent, uniform measurement of the evolution of the logarithmic star formation rate(SFR)-stellarmass(M*)relation, called the main sequence(MS)of star-forming galaxies , for star-forming and all galaxies outto~z5. We measure the MS using mean stacks of 3 GHz radio-continuum images to derive average SFRs forâŒ200,000 mass-selected galaxies at z>0.3 in the COSMOSfield. We describe the MS relation by adopting anew model that incorporates a linear relation at low stellar mass(log(M*/Me)<10)and aflattening at high stellarmass that becomes more prominent at low redshift(z < 1.5).Wefind that the SFR density peaks at 1.5<z<2,and at each epoch there is a characteristic stellar mass(M*=1-4 x 1010Me)that contributes the most to theoverall SFR density. This characteristic mass increases with redshift, at least toz ⌠2.5. Wefind no significant evidence for variations in the MS relation for galaxies in different environments traced by the galaxy numberdensity at 0.3<z<3, nor for galaxies in X-ray groups atz ⌠0.75. We confirm that massive bulge-dominatedgalaxies have lower SFRs than disk-dominated galaxies at afixed stellar mass atz < 1.2. As a consequence, theincrease in bulge-dominated galaxies in the local star-forming population leads to aflattening of the MS at highstellar masses. This indicates that "mass quenching" is linked with changes in the morphological composition ofgalaxies at afixed stellar mass.B.G. acknowledges the support of the Australian
Research Council as the recipient of a Future Fellowship
(FT140101202). Y.P. acknowledges the National Key R&D
Program of China, Grant 2016YFA0400702 and NSFC grant
Nos. 11773001, 11721303, 1199105
A synthesis of approaches for modelling coupled thermalâhydraulicâmechanicalâchemical processes in a single novaculite fracture experiment
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