The meniscus has several roles that contribute to knee function. Many clinical studies have documented the detrimental effects of loss of meniscus function. Meniscal repair is recommended when ...technically and anatomically feasible to preserve meniscal function. Techniques for meniscal repair can be used to transplant meniscal allografts. Animal studies have documented that meniscal allografts can heal in the recipient. There are few clinical studies of meniscal allograft transplantation in humans. Indications, techniques, results, and complications of meniscal allograft transplantation in humans are described.
The beam and detector, used for the NA48 experiment, devoted to the measurement of
Re
(
ε
′
/
ε
)
, and for the NA48/1 experiment on rare
K
S
and neutral hyperon decays, are described.
Shoulder instability is common in young athletes due to acute and repetitive trauma, as well as overuse in athletes with generalized ligamentous laxity. In overhead athletes, instability may present ...as impingement or rotator cuff tenderness. Fortunately, most symptomatic instability can be treatedwith rehabilitation. In athletes with recurrent symptomatic instability despite conservative treatment, surgical stabilization can restore function and allow return to sport.
To compare high‐fidelity simulation and practice in the clinical laboratory to hospital‐based clinical learning on the ability of undergraduate nursing students to assess, intervene, and critically ...think in the obstetric setting.
Quasi‐experimental, nonequivalent comparison groups, post test only; power analysis for three variables, medium effect size required 76 in each comparison group for a total of 152 participants; alpha level .05 and power of .8.
Private university in the Pacific Northwest.
Undergraduate, senior nursing students (80) in the maternal‐child course: 39 in an obstetric hospital rotation and 41 in a pediatric clinical rotation voluntarily participated and comprised the two comparison groups.
Each student demonstrated simulated postpartum and newborn assessments, whereas an obstetric faculty member trained as an observer evaluated performance using check‐off forms. Following and prior to debriefing, students provided written responses to questions designed to assess critical thinking during the simulation. Questions and items on check‐off forms were assigned points to obtain assessment, written, and total scores. Scores <92% required remediation. Check‐off forms, developed by study researchers were tested for inter‐rater reliability and content validity, and questions were pilot tested. t Tests were used to compare scores of students completing an obstetric hospital rotation versus those in a pediatric clinical rotation, and frequencies for passing assessments were calculated.
No significant difference was detected between students in the pediatric clinical rotation who only practiced assessments in the laboratory setting and students completing a hospital‐based obstetric rotation related to ability to assess, intervene, or critically think. The p‐value for comparisons ranged from .41 to .93 (all nonsignificant); less than one third of students passed either assessment.
Simulation is a widely used teaching strategy. Researchers have found simulation increases undergraduate nursing students’ knowledge, skills, self‐efficacy, and confidence. Our findings indicate that simulation was as effective as clinical practice in terms of students’ performance outcomes. Well‐designed simulations can replace part of nursing students’ hands‐on clinical time with positive learning outcomes. Evaluating individual student performance facilitates design of remediation activities targeting identified areas of weakness. Future researchers should combine simulation with hospital‐based clinical experience to determine if student competency improves.
Many studies have shown that the characteristic parameters of an aquifer, specifically the hydraulic conductivity, increase with an increase in the portion of the aquifer tested. The main cause of ...this behavior is the heterogeneity within the aquifer. Sets of measurements performed on an artificial aquifer by different methods are utilized here, because it was verified that the scale dependence of hydraulic conductivity does not depend on the specific method of measurement. The unconfined aquifer in question was created in the laboratory utilizing sandy porous medium with a well-known grain-size distribution. An experimental scaling law of the power type was obtained for the hydraulic conductivity, utilizing values measured at different scales by different methods (on undisturbed soil samples by flux cells, on the artificial aquifer by slug tests and aquifer tests). Similarly, porosity measurements of a direct and indirect type were carried out: the former performed in the laboratory and the latter utilizing a relation between
k and
ϕ based on the particle size analysis of the porous media considered. Successively, a new empirical relationship is proposed here, to derive
ϕ, since the
k values and vice versa, are well-known, the validity of which is limited to the sands with effective grain size between 0.059
mm and 0.82
mm and for volumes of aquifer not higher than those investigated here.
► A sandy box was built in laboratory and utilized as experimental apparatus. ► Different hydraulic conductivity and porosity measurement methods were utilized. ► The scaling behavior of the hydraulic conductivity was investigated. ► A possible scaling effect was investigated also for the porosity.
Gamma beam collimation system and profile imager for ELI-NP Cardarelli, P.; Paternò, G.; Di Domenico, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Volume:
936
Journal Article
Peer reviewed
Open access
ELI-NP-GBS is a high-brilliance gamma source that will produce monochromatic beams in the energy range 0.2–19.5 MeV through inverse Compton scattering. In order to obtain a monochromatic beam a ...collimation of the emission is necessary. Depending on the energy, the angular aperture required to provide the design bandwidth ΔE/E=0.5% is between 70 and 700 μrad. This collimation is provided by a stack of 14 tungsten slits, arranged with a relative rotation around the beam axis, so that the overlap will be a continuously adjustable aperture. To monitor the operation and alignment of the collimation, a set of detectors will provide a complete characterization of the gamma beam, including the measurement of the transverse spatial distribution. For this task a gamma beam profile imager based on a thin scintillator screen and a high-resolution CCD-camera was developed. In this work we briefly present the status of the collimation system and beam profile imager, which were designed, assembled and are currently under test at INFN-Ferrara laboratories.
A γ calorimeter for the monitoring of the ELI-NP beam Veltri, M.; Adriani, O.; Albergo, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Volume:
936
Journal Article
Peer reviewed
The ELI-NP facility will provide a monochromatic, high brilliance γ beam with tunable energy up to 19.5 MeV. The time structure of the beam consists of 32 pulses of 105 photons separated by 16 ns and ...delivered at repetition rate of 100 Hz. In order to match such unprecedented beam specifications and to measure its energy spectrum, intensity and space profile, a characterization system has been developed. This paper will focus on the working principle, the expected performances and the results of tests carried out on a low-Z sampling calorimeter, made of silicon detectors and polyethylene absorbers, which will measure the average beam energy and its intensity. The results of tests performed with an infrared pulsed laser have shown the capability of the detector to cope with the time structure of ELI-NP beam. Further tests carried out at the LABEC facility in Firenze have shown the excellent linearity of the silicon detectors in the energy range relevant to ELI-NP beam.
A model for RPC detectors operating at high rate Carboni, G.; Collazuol, G.; De Capua, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2003, Volume:
498, Issue:
1
Journal Article
Peer reviewed
Open access
We present a simple model to describe the behavior of Resistive Plate Chambers (RPC) exposed to a high particle flux. We show that the RPC current,
I, saturates at large flux values and we explain ...why the dependence of
I on the applied voltage
V
0 is essentially linear. We show that in the saturated regime the current is controlled by the value of the bulk electrode resitivity,
ρ, which is directly related to the performance of the detector at high particle rates. Measuring the
I−
V
0 curve under these conditions offers a simple and direct method to obtain
ρ and to monitor its possible variations.
The ELI-NP facility, currently being built in Bucharest, Romania, will deliver an intense and almost monochromatic γ beam with tunable energy between 0.2 MeV and 19.5 MeV in two different beamlines. ...An articulated beam characterization system will be installed downstream of the collimator of each line. The system will use, as calibration candles, a few selected nuclear levels whose fluorescence condition will be monitored by a Nuclear Resonance Scattering System (NRSS). The NRSS will use a peculiar double-readout approach in order to detect resonant events overwhelming background: both scintillation and Cherenkov photons produced inside the same crystals will be separately read.
•The NRS system will play a crucial role in the characterization of the Eli-NP beam.•It will be able to give a precise absolute energy calibration of the gamma beam.•The determination of the resonance will be achieved using a matrix of BaF/LYSO crystals.•A novel double readout technique shows a very good background rejection power.
We present the final results of an extensive aging test, performed at the CERN Gamma Irradiation Facility on two bakelite Resistive Plate Chambers (RPC) detectors. With a method based on a model ...describing the behaviour of an RPC under high particle flux conditions, we have periodically measured the electrode resistivity ρ of the two RPC prototypes over 3 years. We observed a large spontaneous increase of ρ with time, from the initial value of about 1010Ωcm to more than 200×1010Ωcm. A corresponding degradation of the RPC rate capabilities, from more than 3kHz/cm2 to less than 200Hz/cm2, was observed; the reversibility of the process, using a humid gas mixture, has also been studied. We also present a study of the effects of humidity on the bakelite resistivity using two 10×10cm2 bakelite samples.
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