1,346 research outputs found
Effects of Aging on the Biomechanics of Slips and Falls
Although much has been learned in recent decades about the deterioration of muscular strength, gait adaptations, and sensory degradation among older adults, little is known about how these intrinsic changes affect biomechanical parameters associated with slip-induced fall accidents. In general, the objective of this laboratory study was to investigate the process of initiation, detection, and recovery of inadvertent slips and falls. We examined the initiation of and recovery from foot slips among three age groups utilizing biomechanical parameters, muscle strength, and sensory measurements. Forty-two young, middle-age, and older participants walked around a walking track at a comfortable pace. Slippery floor surfaces were placed on the track over force platforms at random intervals without the participants’ awareness. Results indicated that younger participants slipped as often as the older participants, suggesting that the likelihood of slip initiation is similar across all age groups; however, older individuals’ recovery process was much slower and less effective. The ability to successfully recover from a slip (thus preventing a fall) is believed to be affected by lower extremity muscle strength and sensory degradation among older individuals. Results from this research can help pinpoint possible intervention strategies for improving dynamic equilibrium among older adults
Concept and optical design of the cross-disperser module for CRIRES
This is the peer reviewed version of the following article: Oliva, Ernesto, A. Tozzi, D. Ferruzzi, L. Origlia, A. Hatzes, R. Follert, T. Loewinger et al. "Concept and optical design of the cross-disperser module for CRIRES+." In SPIE Astronomical Telescopes+ Instrumentation, pp. 91477R-91477R. International Society for Optics and Photonics, 2014, which has been published in final form at 10.1117/12.2054381
Multiple and Fast: The Accretion of Ordinary Chondrite Parent Bodies
Although petrologic, chemical and isotopic studies of ordinary chondrites and
meteorites in general have largely helped establish a chronology of the
earliest events of planetesimal formation and their evolution, there are
several questions that cannot be resolved via laboratory measurements and/or
experiments only. Here we propose rationale for several new constraints on the
formation and evolution of ordinary chondrite parent bodies (and by extension
most planetesimals) from newly available spectral measurements and
mineralogical analysis of main belt S-type asteroids (83 objects) and
unequilibrated ordinary chondrite meteorites (53 samples). Based on the latter,
we suggest spectral data may be used to distinguish whether an ordinary
chondrite was formed near the surface or in the interior of its parent body. If
these constraints are correct, the suggested implications include that: i)
large groups of compositionally similar asteroids are a natural outcome of
planetesimal formation and, consequently, meteorites within a given class can
originate from multiple parent bodies; ii) the surfaces of large (up to ~200km)
S-type main-belt asteroids expose mostly the interiors of the primordial
bodies, a likely consequence of impacts by small asteroids (D<10km) in the
early solar system (Ciesla et al. 2013); iii) the duration of accretion of the
H chondrite parent bodies was likely short (instantaneous or in less then ~10^5
yr but certainly not as long as 1 Myr); iv) LL-like bodies formed closer to the
Sun than H-like bodies, a possible consequence of radial mixing and size
sorting of chondrules in the protoplanetary disk prior to accretion.Comment: Accepted for publication in Ap
A Multi-Frequency Radio Study of Supernova Remnant G292.0+1.8 and its Pulsar Wind Nebula
(Abridged) We present a detailed radio study of the young supernova remnant
(SNR) G292.0+1.8 and its associated pulsar PSR J1124-5916, using the Australia
Telescope Compact Array at observing wavelengths of 20, 13 and 6 cm. We find
that the radio morphology of the source consists of three main components: a
polarized flat-spectrum central core coincident with the pulsar J1124-5916, a
surrounding circular steep-spectrum plateau with sharp outer edges and,
superimposed on the plateau, a series of radial filaments with spectra
significantly flatter than their surroundings. HI absorption argues for a lower
limit on the distance to the system of 6 kpc.
The core clearly corresponds to radio emission from a pulsar wind nebula
powered by PSR J1124-5916, while the plateau represents the surrounding SNR
shell. The plateau's sharp outer rim delineates the SNR's forward shock, while
the thickness of the plateau region demonstrates that the forward and reverse
shocks are well-separated. Assuming a distance of 6 kpc and an age for the
source of 2500 yr, we infer an expansion velocity for the SNR of ~1200 km/s and
an ambient density ~0.9 cm^-3. We interpret the flat-spectrum radial filaments
superimposed on the steeper-spectrum plateau as Rayleigh-Taylor unstable
regions between the forward and reverse shocks of the SNR. The flat radio
spectrum seen for these features results from efficient second-order Fermi
acceleration in strongly amplified magnetic fields.Comment: 11 pages of text, plus 7 embedded EPS figures. Accepted to ApJ. Added
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A long-term follow-up of safety and clinical efficacy of NTCELL® [Immunoprotected (Alginate-encapsulated) porcine choroid plexus cells for xenotransplantation] in patients with Parkinson's disease.
INTRODUCTION: In 2019, we published the results of a Phase IIb randomized controlled trial of putaminal encapsulated porcine choroid plexus cell (termed NTCELL®) administration in patients with Parkinson's disease. This study failed to meet its primary efficacy end-point of a change in UPDRS part III score in the 'off' state at 26-weeks post-implant. However, a number of secondary end-points reached statistical significance. We questioned whether with longer follow-up, clinically significant improvements would be observed. For this reason, we decided to follow-up all patients periodically to week 104. Herein, we report the results of this long-term follow-up. METHODS: All 18 patients included in the original study were periodically re-assessed at weeks 52, 78 and 104 post-implant. At each time-point, motor and non-motor function, quality of life and levodopa equivalent daily dose was assessed using a standardized testing battery. RESULTS: At week 104, no significant differences in UPDRS part III scores in the 'off' state were observed in any of the treatment groups compared to baseline. Only a single serious adverse event - hospitalisation due to Parkinson's disease rigidity not responding to changes in medications - was considered potentially related to the implant procedure. There was no evidence of xenogeneic viral transmission. CONCLUSION: Un-blinded, long-duration follow-up to week 104 post-implantation showed no evidence that putaminal NTCELL® administration produces significant clinical benefit in patients with moderately advanced Parkinson's disease
Differential impact of two risk communications on antipsychotic prescribing to people with dementia in Scotland: segmented regression time series analysis 2001-2011
The two risk communications were associated with reductions in antipsychotic use, in ways which were compatible with marked differences in their content and dissemination. Further research is needed to ensure that the content and dissemination of regulatory risk communications is optimal, and to track their impact on intended and unintended outcomes. Although rates are falling, antipsychotic prescribing in dementia in Scotland remains unacceptably hig
Data incongruence and the problem of avian louse phylogeny
Recent studies based on different types of data (i.e. morphological and molecular) have supported conflicting phylogenies for the genera of avian feather lice (Ischnocera: Phthiraptera). We analyse new and published data from morphology and from mitochondrial (12S rRNA and COI) and nuclear (EF1-) genes to explore the sources of this incongruence and explain these conflicts. Character convergence, multiple substitutions at high divergences, and ancient radiation over a short period of time have contributed to the problem of resolving louse phylogeny with the data currently available. We show that apparent incongruence between the molecular datasets is largely attributable to rate variation and nonstationarity of base composition. In contrast, highly significant character incongruence leads to topological incongruence between the molecular and morphological data. We consider ways in which biases in the sequence data could be misleading, using several maximum likelihood models and LogDet corrections. The hierarchical structure of the data is explored using likelihood mapping and SplitsTree methods. Ultimately, we concede there is strong discordance between the molecular and morphological data and apply the conditional combination approach in this case. We conclude that higher level phylogenetic relationships within avian Ischnocera remain extremely problematic. However, consensus between datasets is beginning to converge on a stable phylogeny for avian lice, at and below the familial rank
Therapeutic phlebotomy is safe in children with sickle cell anaemia and can be effective treatment for transfusional iron overload
Serial phlebotomy was performed on sixty children with sickle cell anaemia, stroke and transfusional iron overload randomized to hydroxycarbamide in the Stroke With Transfusions Changing to Hydroxyurea trial. There were 927 phlebotomy procedures with only 33 adverse events, all of which were grade 2. Among 23 children completing 30 months of study treatment, the net iron balance was favourable (-8.7 mg Fe/kg) with significant decrease in ferritin, although liver iron concentration remained unchanged. Therapeutic phlebotomy was safe and well-tolerated, with net iron removal in most children who completed 30 months of protocol-directed treatment
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