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

Hypertension in pregnancy

Hypertension is the most common medical problem encountered during pregnancy, complicating 2-3% of pregnancies. Hypertensive disorders during pregnancy are classified into 4 categories: chronic hypertension, pre-eclampsia/eclampsia, pre-eclampsia superimposed on chronic hypertension, and gestational hypertension. A relative paucity of investigative data, as well as the frequent difficulty in making an etiological diagnosis, may lead to problems in its management. This case report analyses current concepts regarding the hypertensive disorders of gestation, focusing on chronic hypertension. Chronic hypertension is defined as blood pressure exceeding 140/90 mmHg before pregnancy or before 20 weeks gestation. Hypertensive disorders in pregnancy may cause maternal and fetal morbidity and remain a leading source of maternal mortality. A prompt diagnosis is needed also because hypertension may be an indicator of pre-eclampsia, a condition which can evolve into serious complications. Maintaining blood pressure below 140/90 mmHg is recommended, although treatment should be determined on an individual basis. Many anti-hypertensive agents appear to be safe for use during pregnancy: methildopa has been the most studied of the anti-hypertensive drugs and has the best safety record. Labetalol, idralazine and nifedipine also have been found to be safe; ACE-inhibitors are absolutely contraindicated, because they are associated with intrauterine growth retardation

Geant4 simulations of soft proton scattering in X-ray optics. A tentative validation using laboratory measurements

Low energy protons (< 300 keV) can enter the field of view of X-ray space telescopes, scatter at small incident angles, and deposit energy on the detector, causing intense background flares at the focal plane or in the most extreme cases, damaging the X-ray detector. A correct modelization of the physics process responsible for the grazing angle scattering processes is mandatory to evaluate the impact of such events on the performance of future X-ray telescopes as the ESA ATHENA mission. For the first time the Remizovich model, in the approximation of no energy losses, is implemented top of the Geant4 release 10.2. Both the new scattering physics and the built-in Coulomb scattering are used to reproduce the latest experimental results on grazing angle proton scattering. At 250 keV multiple scattering delivers large proton angles and it is not consistent with the observation. Among the tested models, the single scattering seems to better reproduce the scattering efficiency at the three energies but energy loss obtained at small scattering angles is significantly lower than the experimental values. In general, the energy losses obtained in the experiment are higher than what obtained by the simulation. The experimental data are not completely representative of the soft proton scattering experienced by current X-ray telescopes because of the lack of measurements at low energies (< 200 keV) and small reflection angles, so we are not able to address any of the tested models as the one that can certainly reproduce the scattering behavior of low energy protons expected for the ATHENA mission. We can, however, discard multiple scattering as the model able to reproduce soft proton funneling, and affirm that Coulomb single scattering can represent, until further measurements, the best approximation of the proton scattered angular distribution at the exit of X-ray optics.Comment: submitted to Experimental Astronom

Fattening system influences fatty acids composition in organic Maremmana bullocks

Organic UE Regulation No 889/2008 states that, in the choice of breeds or strains, account shall be taken of the capacity of animals to adapt to local conditions, their vitality and their resistance to disease. Preference is to be given to indigenous breeds and strains. Maremmana is a very rustic and long-lived Italian cattle breed, which seems to be the direct descendant of Italian aurochs (Bos primigenius) (Giorgetti et al., 2009). Selection has always been directed towards disease resistance and adaptation to the harsh environment, where Maremmana cattle live, and generally these cattle never are treated against parasites (Martini, 2001). Maremmana cattle can graze all the year, utilizing, in the summer and winter periods, the Mediterranean scrub as source of food and refuge. Rearing system, quality of the pasture and possible concentrate integrations can influence the quality of meat and its fatty acid composition. The aim of this research is to compare the fatty acid muscle composition of Maremmana bullocks reared in different fattening systems

Evidence of early stage precursors of polymer crystals by dielectric spectroscopy

Dielectric spectra of the polyester poly(propylene succinate) were measured upon crystallization. For this model aliphatic polyester the α and β relaxations appear simultaneously and are well resolved in the experimental frequency window. During isothermal crystallization, this fact allows one to use the β relaxation to characterize the crystalline structural development while the α relaxation provides information about the evolution of the amorphous phase dynamics. In this way structure development and dynamics evolution can be characterized by a single experiment during the crystallization process. The unambiguous analysis of the dielectric loss clearly supports the existence of precursors of crystallization in the induction period. © 2007 The American Physical Society.Finnancial support from the MCYT (Grant No. MAT2005-01768), Spain.Peer Reviewe

Hypertension in pregnancy

Hypertension is the most common medical problem encountered during pregnancy, complicating 2-3% of pregnancies. Hypertensive disorders during pregnancy are classified into 4 categories: chronic hypertension, pre-eclampsia/eclampsia, pre-eclampsia superimposed on chronic hypertension, and gestational hypertension. A relative paucity of investigative data, as well as the frequent difficulty in making an etiological diagnosis, may lead to problems in its management. This case report analyses current concepts regarding the hypertensive disorders of gestation, focusing on chronic hypertension. Chronic hypertension is defined as blood pressure exceeding 140/90 mmHg before pregnancy or before 20 weeks gestation. Hypertensive disorders in pregnancy may cause maternal and fetal morbidity and remain a leading source of maternal mortality. A prompt diagnosis is needed also because hypertension may be an indicator of pre-eclampsia, a condition which can evolve into serious complications. Maintaining blood pressure below 140/90 mmHg is recommended, although treatment should be determined on an individual basis. Many anti-hypertensive agents appear to be safe for use during pregnancy: methildopa has been the most studied of the anti-hypertensive drugs and has the best safety record. Labetalol, idralazine and nifedipine also have been found to be safe; ACE-inhibitors are absolutely contraindicated, because they are associated with intrauterine growth retardation

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

Autothermal biochar production and characterization at pilot scale

The present work reports on the results from the validation campaign of an autothermal pilot carbonization unit (CarbON) and on the characterization of the produced biochar and pyrolysis vapors. The proposed pilot plant leverages the simplicity and effectiveness of autothermal operations together with open top, downdraft design, to bring to the small scale the performance of larger installations. In autothermal operation, heat for the process is internally provided by combusting part of the feedstock and evolved volatiles inside the reactor, the so called “oxidative pyrolysis”. Please click on the file below for full content of the abstract

Biochar performances as drug-carrier of bioactive molecules used for intestinal disease treatment

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