29 research outputs found
Very metal-poor stars in the solar vicinity: kinematics and abundance analysis
Very metal-poor stars contain crucial information on the Milky Way's infancy.
In our previous study \citep{Plotnikova_2022} we derived a mean age of
13.7 Gyr for a sample of these stars in the Sun's vicinity. In this work, we
investigate the chemical and kinematics properties of these stars with the goal
of obtaining some insights on their origin and their parent population. We did
not find any Al-Mg anti-correlation, which lead us to the conclusion that these
stars did not form in globular clusters, while the detailed analysis of their
orbital parameters reveals that these stars are most probably associated with
the pristine Bulge of the Milky Way. We then sketch a scenario for the
formation of the Milky Way in which the first structure to form was the Bulge
through rapid collapse. The other components have grown later on, with a
significant contribution of accreted structures.Comment: 13 pages, 10 figures, accepted for publication in the Astrophysical
Journa
Validation of the angular measurements of a new inertial-measurement-unit based rehabilitation system: comparison with state-of-the-art gait analysis
Background: Several rehabilitation systems based on inertial measurement units (IMU) are entering the market for the control of exercises and to measure performance progression, particularly for recovery after lower limb orthopaedic treatments. IMU are easy to wear also by the patient alone, but the extent to which IMU's malpositioning in routine use can affect the accuracy of the measurements is not known. A new such system (Riabloâą, CoRehab, Trento, Italy), using audio-visual biofeedback based on videogames, was assessed against state-of-the-art gait analysis as the gold standard.Methods. The sensitivity of the system to errors in the IMU's position and orientation was measured in 5 healthy subjects performing two hip joint motion exercises. Root mean square deviation was used to assess differences in the system's kinematic output between the erroneous and correct IMU position and orientation.In order to estimate the system's accuracy, thorax and knee joint motion of 17 healthy subjects were tracked during the execution of standard rehabilitation tasks and compared with the corresponding measurements obtained with an established gait protocol using stereophotogrammetry.Results: A maximum mean error of 3.1 ± 1.8 deg and 1.9 ± 0.8 deg from the angle trajectory with correct IMU position was recorded respectively in the medio-lateral malposition and frontal-plane misalignment tests. Across the standard rehabilitation tasks, the mean distance between the IMU and gait analysis systems was on average smaller than 5°.Conclusions: These findings showed that the tested IMU based system has the necessary accuracy to be safely utilized in rehabilitation programs after orthopaedic treatments of the lower limb
Predicting needlestick and sharps injuries in nursing students: Development of the SNNIP scale
© 2020 The Authors. Nursing Open published by John Wiley & Sons Ltd. Aim: To develop an instrument to investigate knowledge and predictive factors of needlestick and sharps injuries (NSIs) in nursing students during clinical placements. Design: Instrument development and cross-sectional study for psychometric testing. Methods: A self-administered instrument including demographic data, injury epidemiology and predictive factors of NSIs was developed between October 2018âJanuary 2019. Content validity was assessed by a panel of experts. The instrument's factor structure and discriminant validity were explored using principal components analysis. The STROBE guidelines were followed. Results: Evidence of content validity was found (S-CVI 0.75; I-CVI 0.50â1.00). A three-factor structure was shown by exploratory factor analysis. Of the 238 participants, 39% had been injured at least once, of which 67.3% in the second year. Higher perceptions of âpersonal exposureâ (4.06, SD 3.78) were reported by third-year students. Higher scores for âperceived benefitsâ of preventive behaviours (13.6, SD 1.46) were reported by second-year students
Load along the tibial shaft during activities of daily living
External load at the tibia during activities of daily living provides baseline measures for the improvement of the design of the bone-implant interface for relevant internal and external prostheses. A motion analysis system was used together with an established protocol with skin markers to estimate three-dimensional forces and moments acting on ten equidistant points along the tibial shaft. Twenty young and able-bodied volunteers were analysed while performing three repetitions of the following tasks: level walking at three different speeds, in a straight-line and with sudden changes of direction to the right and to the left, stair ascending and descending, squatting, rising from a chair and sitting down. Moment and force patterns were normalised to the percentage of body weight per height and body weight, respectively, and then averaged over all subjects for each point, about the three tibial anatomical axes, and for each task. Load patterns were found to be consistent over subjects, but different among the anatomical axes, tasks and points. Generally, moments were higher in the medio/lateral axis and influenced by walking speed. In all five walking tasks and in ascending stairs with alternating feet, the more proximal the point was the smaller the mean moment was. For the remaining tasks the opposite trend was observed. The overall largest value was observed in the medio/lateral direction at the ankle centre in level walking at high speed (9.1% body weight * height on average), nearly three times larger than that of the anterior/posterior axis (2.9) during level walking with a sidestep turn. The present results should be of value also for in-vitro mechanical tests and finite element models