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The solar wind plasma is a fully ionized and turbulent gas ejected by the outer layers of the solar corona at very high speed, mainly composed by protons and electrons, with a small percentage of helium nuclei and a significantly lower abundance of heavier ions. Since particle collisions are practically negligible, the solar wind is typically not in a state of thermodynamic equilibrium. Such a complex system must be described through self-consistent and fully nonlinear models, taking into account its multi-species composition and turbulence. We use a kinetic hybrid Vlasov-Maxwell numerical code to reproduce the turbulent energy cascade down to ion kinetic scales, in typical conditions of the uncontaminated solar wind plasma, with the aim of exploring the differential kinetic dynamics of the dominant ion species, namely protons and alpha particles. We show that the response of different species to the fluctuating electromagnetic fields is different. In particular, a significant differential heating of alphas with respect to protons is observed. Interestingly, the preferential heating process occurs in spatial regions nearby the peaks of ion vorticity and where strong deviations from thermodynamic equilibrium are recovered. Moreover, by feeding a simulator of a top-hat ion spectrometer with the output of the kinetic simulations, we show that measurements by such spectrometer planned on board the Turbulence Heating ObserveR (THOR mission), a candidate for the next M4 space mission of the European Space Agency, can provide detailed three-dimensional ion velocity distributions, highlighting important non-Maxwellian features. These results support the idea that future space missions will allow a deeper understanding of the physics of the interplanetary medium.

Study design:Secondary analysis of data from a prospective cohort study.Objectives:The objective of this study was to identify the medical and demographic factors associated with the development of pressure ulcers during acute-care hospitalization and inpatient rehabilitation following acute spinal cord injury.Setting:The study was carried out at acute hospitalization, inpatient rehabilitation and outpatient rehabilitation sites at a university medical center in the United States.Methods:Adults with acute traumatic spinal cord injury (n=104) were recruited within 24-72 h of admission to the hospital. Pressure ulcer incidence was recorded.Results:Thirty-nine participants out of 104 (37.5%) developed at least one pressure ulcer during acute-care hospitalization and inpatient rehabilitation. Univariate logistic regression analyses revealed significant association of pressure ulcer incidence for those with pneumonia and mechanical ventilation (P=0.01) and higher injury severity (ASIA A) (P=0.01). Multiple logistic regression showed that the odds of formation of a first pressure ulcer in participants with ASIA A was 4.5 times greater than that for participants with ASIA B, CI (1-20.65), P=0.05, and 4.6 times greater than that for participants with ASIA C, CI (1.3-16.63), P=0.01.Conclusion:Among individuals with acute traumatic SCI, those with high-injury severity were at an increased risk to develop pressure ulcers. Pneumonia was noted to be associated with the formation of pressure ulcers.

The X-IFU is the cryogenic spectrometer onboard the future ATHENA X-ray observatory. It is based on a large array of TES microcalorimeters, which work in combination with a Cryogenic AntiCoincidence detector (CryoAC). This is necessary to reduce the particle background level thus enabling part of the mission science goals. Here we present the first joint test of X-IFU TES array and CryoAC Demonstration Models, performed in a FDM setup. We show that it is possible to operate properly both detectors, and we provide a preliminary demonstration of the anti-coincidence capability of the system achieved by the simultaneous detection of cosmic muons.

The Cryogenic AntiCoincidence detector (CryoAC) of ATHENA X-IFU is designed to reduce the particle background of the instrument and to enable the mission science goals. It is a 4-pixel silicon microcalorimeter sensed by an Ir/Au TES network. We have developed the CryoAC demonstration model, a prototype aimed to probe the critical technologies of the detector, i.e., the suspended absorber with an active area of 1 cm 2 ; the low energy threshold of 20 keV; and the operation connected to a 50 mK thermal bath with a power dissipation less than 40 nW. Here, we report the test performed on the first CryoAC DM sample (namely, the AC-S10 prototype), showing that it is fully compliant with its requirements.

We are developing the Cryogenic AntiCoincidence detector (CryoAC) of the ATHENA X-IFU spectrometer. It is a TES-based particle detector aimed to reduce the background of the instrument. Here, we present the result obtained with the last CryoAC single-pixel prototype. It is based on a 1 cm 2 silicon absorber sensed by a single 2 mm × 1 mm Ir/Au TES, featuring an on-chip heater for calibration and diagnostic purposes. We have illuminated the sample with 55 Fe (6 keV line) and 241 Am (60 keV line) radioactive sources, thus studying the detector response and the heater calibration accuracy at low energy. Furthermore, we have operated the sample in combination with a past-generation CryoAC prototype. Here, by analyzing the coincident detections between the two detectors, we have been able to characterize the background spectrum of the laboratory environment and disentangle the primary (i.e. cosmic muons) and secondaries (mostly secondary photons and electrons) signatures in the spectral shape.

The ATHENA observatory is the second large class ESA mission to be launched on 2031 at L2 orbit. One of the two onboard instruments is X-IFU, a TES-based kilo-pixel array able to perform simultaneous high-grade energy spectroscopy (FWHM 2.5 eV@7 keV) and imaging over the 5′ field of view. The X-IFU sensitivity is degraded by primary particle background of both solar and galactic cosmic ray (GCR) origins, and by secondary electrons produced by primaries, interacting with the materials surrounding the detector: These particles cannot be distinguished by the scientific photons, thus degrading the instrument performance. Results from studies regarding the GCR component performed by Geant4 simulations address the necessity to use background reduction techniques to enable the study of several key science topics. This is feasible by combining an active Cryogenic AntiCoincidence detector (CryoAC) and a passive electron shielding to reach the required residual particle background of 0.005 cts/cm 2 /s/keV inside the 2–10 keV scientific energy band. The CryoAC is a four-pixel detector made of Si-suspended absorbers sensed by a network of IrAu TESes and placed at a distance < 1 mm below the TES array. Here we will provide an overview of the CryoAC program, starting with some details on the background assessment having impacts on the CryoAC design; then, we continue with its design concept including electronics and the Demonstration Model results, to conclude with programmatic aspects.

Study design: Two-way factorial mixed design, the between-subjects factor as the spinal cord injury (SCI) status (SCI and non-SCI) and the within-subjects factor as the pressure pattern (alternating and constant pressures). Objectives: To compare the effects of alternating and constant pressures on weight-bearing tissue perfusion in people with SCI, with application for improving alternating pressure support surface usage. Setting: University research laboratory. Subjects: A total of 28 participants were studied, 7 participants with cervical injury, 7 participants with injury below T6 and 14 healthy controls. Methods: Sacral skin perfusion was continuously measured using laser Doppler flowmetry under 10 min preloading, 20 min loading (alternating or constant pressures) and 10 min postloading. Alternating pressure was applied with low-interface pressure at 0 mm Hg and high-interface pressure at 60 mm Hg with a cycle time of 5 min; constant pressure was applied with interface pressure at 30 mm Hg. Results: The results showed that pressure pattern affects skin perfusion responses in weight-bearing tissues ( P <0.01). Alternating pressure stimulates an increase in skin perfusion (1.21±0.08 au) as compared with constant pressure (0.74±0.07 au) in people with SCI ( P <0.01). There was no overall difference in the skin perfusion responses of patients with SCI as compared with non-SCI patients ( P >0.05). Conclusion: This study has shown that alternating pressure enhances the skin perfusion of weight-bearing tissues as compared with constant pressure in people with SCI. The protocol tested in this study may be used to guide the selection of parameters of commercial alternating pressure support surfaces for preventing pressure ulcers in people with SCI.

The Dust Complex (DC) instrument was designed to be installed on the landing platform of the ExoMars project. The purpose of the experiment is to study the dynamics of dust particles in the near-surface atmosphere of Mars and to evaluate the main characteristics of the near-surface medium that determine their dynamics. The device makes it possible to register dust particles in the near-surface atmosphere of Mars, determine the main parameters and measure some characteristics of the plasma-dust medium related to the dynamics of dust particles near the Martian surface. The article provides a description of the device, its blocks and sensors, the main elements of the measurement program and characteristics of the measured parameters.

Pressure-induced skin blood flow responses measured via laser Doppler flowmetry are commonly reported in the time domain. The usefulness of spectral analysis in examining blood flow control mechanisms has been demonstrated, but traditional Fourier analysis does not provide sufficient resolution to reveal characteristic low frequencies. Time-frequency (wavelet) analysis was performed on 10 subjects' sacral skin blood flow responses to heating (45 degrees C) with improved resolution. Five frequency bands were identified (0.008-0.02 Hz, 0.02-0.05 Hz, 0.05-0.15 Hz, 0.15-0.4 Hz, and 0.4-2.0 Hz) corresponding to metabolic, neurogenic, myogenic, respiratory, or cardiac origins. Significant differences were observed in the mean normalized power of the metabolic (p < 0.01) and myogenic frequency bands (p < 0.01) between preheating and maximal heating and preheating and postheating periods. Power increased for the metabolic frequency and decreased for the myogenic frequency. Wavelet analysis successfully characterized thermoregulatory control mechanisms by revealing the contributions of the physiological rhythms embedded in the blood flow signal.

The ABM was calibrated to serial images of post-SCI pressure ulcers obtained following institutional review board approval and informed consent.