200 research outputs found
The Cryogenic AntiCoincidence detector for ATHENA X-IFU: a scientific assessment of the observational capabilities in the hard X-ray band
ATHENA is a large X-ray observatory, planned to be launched by ESA in 2028
towards an L2 orbit. One of the two instruments of the payload is the X-IFU: a
cryogenic spectrometer based on a large array of TES microcalorimeters, able to
perform integral field spectrography in the 0.2-12 keV band (2.5 eV FWHM at 6
keV). The X-IFU sensitivity is highly degraded by the particle background
expected in the L2 orbit, which is induced by primary protons of both galactic
and solar origin, and mostly by secondary electrons. To reduce the particle
background level and enable the mission science goals, the instrument
incorporates a Cryogenic AntiCoincidence detector (CryoAC). It is a 4 pixel TES
based detector, placed <1 mm below the main array. In this paper we report a
scientific assessment of the CryoAC observational capabilities in the hard
X-ray band (E>10 keV). The aim of the study has been to understand if the
present detector design can be improved in order to enlarge the X-IFU
scientific capability on an energy band wider than the TES array. This is
beyond the CryoAC baseline, being this instrument aimed to operate as
anticoincidence particle detector and not conceived to perform X-ray
observations.Comment: Accepted for publication on Experimental Astronom
Analysing long-term opportunities for offshore energy system integration in the Danish North Sea
Acknowledgment The authors gratefully acknowledge the financial support of the Danish Hydrocarbon Research and Technology centre (DHRTC) for funding this research in the context of the “Alternative use of offshore infrastructures and reservoirs” program. Any remaining errors are the authors’ responsibility.Peer reviewedPublisher PD
Updates on the background estimates for the X-IFU instrument onboard of the ATHENA mission
ATHENA, with a launch foreseen in 2028 towards the L2 orbit, addresses the
science theme "The Hot and Energetic Universe", coupling a high-performance
X-ray Telescope with two complementary focal-plane instruments. One of these,
the X-ray Integral Field Unit (X-IFU) is a TES based kilo-pixel array providing
spatially resolved high-resolution spectroscopy (2.5 eV at 6 keV) over a 5
arcmin FoV. The background for this kind of detectors accounts for several
components: the diffuse Cosmic X-ray Background, the low energy particles
(<~100 keV) focalized by the mirrors and reaching the detector from inside the
field of view, and the high energy particles (>~100 MeV) crossing the
spacecraft and reaching the focal plane from every direction. Each one of these
components is under study to reduce their impact on the instrumental
performances. This task is particularly challenging, given the lack of data on
the background of X-ray detectors in L2, the uncertainties on the particle
environment to be expected in such orbit, and the reliability of the models
used in the Monte Carlo background computations. As a consequence, the
activities addressed by the group range from the reanalysis of the data of
previous missions like XMM-Newton, to the characterization of the L2
environment by data analysis of the particle monitors onboard of satellites
present in the Earth magnetotail, to the characterization of solar events and
their occurrence, and to the validation of the physical models involved in the
Monte Carlo simulations. All these activities will allow to develop a set of
reliable simulations to predict, analyze and find effective solutions to reduce
the particle background experienced by the X-IFU, ultimately satisfying the
scientific requirement that enables the science of ATHENA. While the activities
are still ongoing, we present here some preliminary results already obtained by
the group
Venous wall ultrastructure in generalized venomegaly.
The ultrastructure of thè v. colica sinistra in a case of generalized vasomegaìy
in man was examined. Elastic material was found in three forms: as a lightly osmiophii
amorphous material bordering on myocytes, as a highly osmiophii elastic membrana,
and as highly osmiophii slim elastic fibres of different orientation in thè tunica media
and adventitia. The slightly osmiophii elastic material is assumed to be newly formed.
by pinocytotic activity of thè myocytes. The highly osmiophii elastic material indicatss
its impairment. No typical atherosclerotic changes were found in thè examined vein.
Based on a comparison with previous findings in thè case of vasomegaìy of thè
a. mesenterica inferior, thè authors conclude that thè venomegaly phenomenon is connected
with degenerative changes in thè elastic material of thè vessel wall
Urothelial bladder carcinoma metastasizing to the eye: a systematic review and case report
The eye is a rare site for disseminated malignancies; nevertheless, several tumors may metastasize to ocular structures. Few cases of urothelial and bladder cancer with eye involvement have been described in the literature thus far. The rarity of metastatic ocular localization implies an accurate differential diagnosis among the possible primary tumor sites. However, a specific diagnostic algorithm is not currently available, nor a defined therapeutic approach. Eye metastases are associated with advanced disease and poor prognosis. Physicians should be made aware of the possibility of eye involvement in patients with a past medical history of urothelial bladder cancer associated with ocular symptoms. The present case reports discusses the first documented case, to the best of our knowledge, of an urothelial bladder cancer metastasizing to the retro bulbar region that infiltrates the lacrimal gland. Furthermore, the report provides a systematic qualitative review of the current literature on eye metastases from urothelial bladder cancer using the Preferred Reporting Items for Systematic Reviews and Meta Analyses
Time- and frequency-resolved fluorescence with a single TCSPC detector via a Fourier-transform approach
We introduce a broadband single-pixel spectro-temporal fluorescence detector, combining time-correlated single photon counting (TCSPC) with Fourier transform (FT) spectroscopy. A birefringent common-path interferometer (CPI) generates two time-delayed replicas of the sample's fluorescence. Via FT of their interference signal at the detector, we obtain a two-dimensional map of the fluorescence as a function of detection wavelength and emission time, with high temporal and spectral resolution. Our instrument is remarkably simple, as it only requires the addition of a CPI to a standard single-pixel TCSPC system, and it shows a readily adjustable spectral resolution with inherently broad bandwidth coverage
Functional modulation of LHCSR1 protein from Physcomitrella patens by zeaxanthin binding and low pH
Light harvesting for oxygenic photosynthesis is regulated to prevent the formation of harmful photoproducts by activation of photoprotective mechanisms safely dissipating the energy absorbed in excess. Lumen acidification is the trigger for the formation of quenching states in pigment binding complexes. With the aim to uncover the photoprotective functional states responsible for excess energy dissipation in green algae and mosses, we compared the fluorescence dynamic properties of the light-harvesting complex stress-related (LHCSR1) protein, which is essential for fast and reversible regulation of light use efficiency in lower plants, as compared to the major LHCII antenna protein, which mainly fulfills light harvesting function. Both LHCII and LHCSR1 had a chlorophyll fluorescence yield and lifetime strongly dependent on detergent concentration but the transition from long- to short-living states was far more complete and fast in the latter. Low pH and zeaxanthin binding enhanced the relative amplitude of quenched states in LHCSR1, which were characterized by the presence of 80 ps fluorescence decay components with a red-shifted emission spectrum. We suggest that energy dissipation occurs in the chloroplast by the activation of 80 ps quenching sites in LHCSR1 which spill over excitons from the photosystem II antenna system
EACVI survey on hypertrophic cardiomyopathy
Publisher Copyright: Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2021. For permissions, please email: [email protected]: The European Association of Cardiovascular Imaging (EACVI) Scientific Initiatives Committee performed a global survey to evaluate current practice for the assessment and management of patients with hypertrophic cardiomyopathy (HCM). METHODS AND RESULTS: A total of 213 centres from 38 different countries (87% European) responded to the survey. One hundred twenty-one (57%) centres followed HCM patients in a general cardiology outpatient clinic and 85 (40%) centres in a specialized HCM/cardiomyopathy clinic. While echocardiography was the primary imaging modality, cardiovascular magnetic resonance (CMR) has become an important complementary tool. Cardiac anatomy, left ventricular (LV) systolic, and diastolic function were assessed according to current European guidelines and recommendations. To evaluate LV obstruction, 49% of the centres performed bedside provocation manoeuvres in every patient and 55% of the centres used exercise stress echocardiography. The majority of centres used the 5-year risk assessment of sudden cardiac death (SCD) calculated with the HCM Risk-SCD score. However, 34% of the centres also used extensive non-infarct late gadolinium enhancement on CMR and 27% the presence of LV apical aneurysm to help select patients for primary prevention implantable cardioverter-defibrillator therapy. Ninety-nine percent of the responding centres performed regular imaging follow-up of HCM patients. CONCLUSION: Most centres followed European guidelines and recommendations for the diagnosis and management of patients with HCM. The importance of bedside provocation manoeuvres and exercise stress echocardiography to diagnose LV outflow obstruction requires emphasis. Additional risk markers for SCD are used in many centres and might indicate the need for an update of current European recommendations.publishersversionpublishe
Estimates for the background of the ATHENA X-IFU instrument: the cosmic rays contribution
The background of the ATHENA X-IFU instrument is evaluated by Geant4 simulations. A new, highly detailed, mass model of the X-IFU and of its cryostat has been produced, a new model for the Galactic Cosmic Ray protons in L2 has been developed from satellite data, and a set of physics models tuned to ATHENA needs has been refined through extensive validations against experimental results. We are going to report the latest results in the estimate of the background of the X-IFU instrument, obtained after the update of all the elements of the Geant4 simulations and of the post processing software
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