2,169 research outputs found
Magnetic resonance arthrography in patients with multidirectional instability: could inferior capsulsar width be considered the cornerstone in the diagnosis of non-traumatic shoulder instability?
Objectives To provide quantitative anatomical parameters in patients with and without non-traumatic multidirectional instability using MR arthrography (MR-a). Materials and methods One hundred and seventy-six MR-a performed from January 2020 to March 2021 were retrospectively evaluated. Patients were divided according to the presence of clinically diagnosed multidirectional shoulder instability (MDI). Each MR-a was performed immediately after intra-articular injection of 20 ml of gadolinium using the anterior approach. The width of the axillary recess, the width of the rotator interval, and the circumference of the glenoid were measured by three independent radiologists, choosing the average value of the measurements. The difference between the mean values of each of the three parameters between the two study groups was then assessed. Results Thirty-seven patients were included in the study (20 in the MDI group, 17 in the control group). The mean axillary recess width in the MDI group was significantly greater than in the control group (t(33) = 3.15, p = .003); rotator interval width and glenoid circumference measurements were not significantly different (t(35) = 1.75, p = .08 and t(30) = 0,51, p = .6, respectively). Conclusions Inferior capsular redundancy may be an important predisposing factor in MDI, while glenoid circumference is not related to MDI. The relationship between the width of the rotator interval and shoulder instability remains debated
Magnetic assessment and modelling of the Aramis undulator beamline
Within the SwissFEL project at the Paul Scherrer Institute (PSI), the hard X-ray line (Aramis) has been equipped with short-period in-vacuum undulators, known as the U15 series. The undulator design has been developed within the institute itself, while the prototyping and the series production have been implemented through a close collaboration with a Swiss industrial partner, Max Daetwyler AG, and several subcontractors. The magnetic measurement system has been built at PSI, together with all the data analysis tools. The Hall probe has been designed for PSI by the Swiss company SENIS. In this paper the general concepts of both the mechanical and the magnetic properties of the U15 series of undulators are presented. A description of the magnetic measurement equipment is given and the results of the magnetic measurement campaign are reported. Lastly, the data reduction methods and the associated models are presented and their actual implementation in the control system is detailed.peer-reviewe
Isotopic characterization of Italian industrial hemp (Cannabis sativa L.) intended for food use: a first exploratory study
In this study, Italian industrial hemp (Cannabis sativa L.) intended for food use was isotopically characterized for the first time. The stable isotope ratios of five bioelements were analyzed in different parts of the plant (i.e., roots, stems, inflorescences, and seeds) sampled in eight different regions of Italy, and in five hemp seed oils. The values of δ2H, δ13C, δ18O, and δ34S differed according to the latitude and, therefore, to the geographical origin of the samples and the climate conditions of plant growth, while the δ15N values allowed us to distinguish between crops grown under conventional and organic fertilization. The findings from this preliminary study corroborate the reliability of using light stable isotope ratios to characterize hemp and its derived food products and contribute to the creation of a first isotopic database for this plant, paving the way for future studies on authentication, traceability, and verification of organic labelin
Design and development of a reduced form-factor high accuracy three-axis teslameter
Acknowledgments: The authors would like to thank Reuben Debono for his useful guidance and help in the
PCB assembly of the instruments at the Electronic Systems Lab at the Faculty of Engineering at University of
Malta. The authors would like to thank R. Ganter, project leader of the Athos undulator beamline and H-H.
Braun, SwissFEL machine director, for their constant support throughout the entire project. The authors would
like to thank Sasa Spasic and his team at Sentronis facilities for their fruitful discussions and their guidance
during testing.A novel three-axis teslameter and other similar machines have been designed and developed for SwissFEL at the Paul Scherrer Institute (PSI). The developed instrument will be used for high fidelity characterisation and optimisation of the undulators for the ATHOS soft X-ray beamline. The teslameter incorporates analogue signal conditioning for the three-axes interface to a SENIS Hall probe, an interface to a Heidenhain linear absolute encoder and an on-board high-resolution 24-bit analogue-to-digital conversion. This is in contrast to the old instrumentation setup used, which only comprises the analogue circuitry with digitization being done externally to the instrument. The new instrument fits in a volumetric space of 150 mm × 50 mm × 45 mm, being very compact in size and also compatible with the in-vacuum undulators. This paper describes the design and the development of the different components of the teslameter. Performance results are presented that demonstrate offset fluctuation and drift (0.1–10 Hz) with a standard deviation of 0.78 µT and a broadband noise (10–500 Hz) of 2.05 µT with an acquisition frequency of 2 kHz.peer-reviewe
Calibration and characterization of a reduced form-factor high accuracy three-axis teslameter
A new reduced form-factor three axes digital teslameter, based on the spinning current technique, has been developed. This instrument will be used to characterize the SwissFEL insertion devices at the Paul Scherrer Institute (PSI) for the ATHOS soft X-ray beamline. A detailed and standardized calibration procedure is critical to optimize the performance of this precision instrument. This paper presents the measurement techniques used for the corrective improvements implemented through non-linearity, temperature offset, temperature sensitivity compensation of the Hall probe and electronics temperature compensation. A detailed quantitative analysis of the reduction in errors on the application of each step of the calibration is presented. The percentage peak error reduction attained through calibration of the instrument for reference fields in the range of ±2 T is registered to drop from 1.94% down to 0.02%.peer-reviewe
Performance analysis of a reduced form-factor high accuracy three-axis teslameter
In the framework of the SwissFEL project at the Paul Scherrer Institute (PSI), a Hall probe bench is being developed for the high-precision magnetic characterization of the insertion devices for the ATHOS soft X-ray beamline. For this purpose, a novel three-axis teslameter has been developed, which will be placed between the undulator and its outer shell in a very limited volumetric space of 150 × 50 × 45 mm. Together with a SENIS® 3-axis Hall probe at the center of the cross sectional area of the undulator, the setup will traverse along the undulator length on a specifically designed rig with minimal vibrations. This teslameter has all the analog signal conditioning circuitry for the Hall probe and also has on board 24-bit digitization. The instrument also handles an interface to a linear absolute encoder. The old instrumentation used only had analog signal conditioning circuitry whilst digitization was done off board. The new instrument also provides a very accurate magnetic field map in the µT range with simultaneous readings from the position encoder at an accuracy of ±3 µm. In this paper, a series of tests are described, which were performed at PSI in order to establish the measuring precision and repeatability of the instrument.peer-reviewe
Superdense galaxies and the mass-size relation at low redshift
We search for massive and compact galaxies (superdense galaxies, hereafter
SDGs) at z=0.03-0.11 in the Padova-Millennium Galaxy and Group Catalogue, a
spectroscopically complete sample representative of the local Universe general
field population. We find that compact galaxies with radii and mass densities
comparable to high-z massive and passive galaxies represent 4.4% of all
galaxies with stellar masses above 3 X 10^10 M_sun, yielding a number density
of 4.3 X 10^-4 h^3 Mpc^-3. Most of them are S0s (70%) or ellipticals (23%), are
red and have intermediate-to-old stellar populations, with a median
luminosity-weighted age of 5.4 Gyr and a median mass-weighted age of 9.2 Gyr.
Their velocity dispersions and dynamical masses are consistent with the small
radii and high stellar mass estimates. Comparing with the WINGS sample of
cluster galaxies at similar redshifts, the fraction of superdense galaxies is
three times smaller in the field than in clusters, and cluster SDGs are on
average 4 Gyr older than field SDGs. We confirm the existence of a universal
trend of smaller radii for older luminosity-weighted ages at fixed galaxy mass.
On top of the well known dependence of stellar age on galaxy mass, the
luminosity-weighted age of galaxies depends on galaxy compactness at fixed
mass, and, for a fixed mass and radius, on environment. This effect needs to be
taken into account in order not to overestimate the evolution of galaxy sizes
from high- to low-z. Our results and hierarchical simulations suggest that a
significant fraction of the massive compact galaxies at high-z have evolved
into compact galaxies in galaxy clusters today. When stellar age and
environmental effects are taken into account, the average amount of size
evolution of individual galaxies between high- and low-z is mild, a factor
~1.6. (abridged)Comment: ApJ, in pres
The evolution of galaxy sizes
We present a study of galaxy sizes in the local Universe as a function of
galaxy environment, comparing clusters and the general field. Galaxies with
radii and masses comparable to high-z massive and compact galaxies represent
4.4% of all galaxies more massive than 3 X 10^{10} M_sun in the field. Such
galaxies are 3 times more frequent in clusters than in the field. Most of them
are early-type galaxies with intermediate to old stellar populations. There is
a trend of smaller radii for older luminosity-weighted ages at fixed galaxy
mass. We show the relation between size and luminosity-weighted age for
galaxies of different stellar masses and in different environments. We compare
with high-z data to quantify the evolution of galaxy sizes. We find that, once
the progenitor bias due to the relation between galaxy size and stellar age is
removed, the average amount of size evolution of individual galaxies between
high- and low-z is mild, of the order of a factor 1.6.Comment: to appear in the proceedings of the IAU S295: The intriguing life of
massive galaxies, editors D. Thomas, A. Pasquali & I. Ferrera
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