1,713 research outputs found
Early Globus Pallidus Internus Stimulation in Pediatric Patients With Generalized Primary Dystonia: Long-Term Efficacy and Safety
Primary generalized dystonia presents mainly at a young age and commonly is severely disabling. The authors report the long-term follow-up (mean, 73 months; range, 50-101 months) of 5 pediatric patients (mean age at surgery 13 years; range, 8-16 years) undergoing globus pallidus internus deep brain stimulation. Mean improvement in the Burke-Fahn-Marsden movement score was 67.4% (range, 47.0%-87.5%), 75.4% (range, 61.5%-91.7%), and 83.5% (range, 72.0%-93.3%) at 3 months, 12 months, and long-term follow-up (>36 months), respectively. Hardware problems (electrode dislocation/breakage of extension cable, and imminent perforation of extension cable) were observed in 2 patients (operative revision without sequelae). Except for mild dysarthria in 2 patients, no other therapy-related morbidity was observed. The authors found globus pallidus internus stimulation to offer a very effective and safe therapy in pediatric patients with primary dystonia. Early neurosurgical intervention seems to be crucial to prevent irreversible impairment of motor function
FOOD HABITS OF MOUNTAIN LIONS IN THE TRANS-PECOS REGION OF TEXAS
Information regarding mountain lion (Felis concolor) food habits is relatively scarce overall, and this is particularly true in the Trans-Pecos region of Texas. Most information currently available is from Big Bend National Park where livestock are excluded and game animals are not actively managed. This study involved the analysis of 32 mountain lion stomachs collected throughout the Trans-Pecos over a 14 month period. Deer (Odocoileus spp.) and javelina (Tayassu tajacu) were the predominate prey species, each occurring in 39% of the stomachs analyzed. Domestic livestock was found in 9% of the total stomachs and non-game wildlife in 13%. Samples taken from areas with and without livestock differed significantly (P\u3c0.05). Samples from areas with livestock contained deer (50%), javelina (19%), small game (19%), and livestock (12%). Samples from areas without livestock contained javelina (86%) and deer (14%). No differences (P\u3e0.05) in food habits were found between sexes or among seasons of the year
FOOD HABITS OF MOUNTAIN LIONS IN THE TRANS-PECOS REGION OF TEXAS
Information regarding mountain lion (Felis concolor) food habits is relatively scarce overall, and this is particularly true in the Trans-Pecos region of Texas. Most information currently available is from Big Bend National Park where livestock are excluded and game animals are not actively managed. This study involved the analysis of 32 mountain lion stomachs collected throughout the Trans-Pecos over a 14 month period. Deer (Odocoileus spp.) and javelina (Tayassu tajacu) were the predominate prey species, each occurring in 39% of the stomachs analyzed. Domestic livestock was found in 9% of the total stomachs and non-game wildlife in 13%. Samples taken from areas with and without livestock differed significantly (P\u3c0.05). Samples from areas with livestock contained deer (50%), javelina (19%), small game (19%), and livestock (12%). Samples from areas without livestock contained javelina (86%) and deer (14%). No differences (P\u3e0.05) in food habits were found between sexes or among seasons of the year
Loop-shaping for reset control systems -- A higher-order sinusoidal-input describing functions approach
The ever-growing demands on speed and precision from the precision motion
industry have pushed control requirements to reach the limitations of linear
control theory. Nonlinear controllers like reset provide a viable alternative
since they can be easily integrated into the existing linear controller
structure and designed using industry-preferred loop-shaping techniques.
However, currently, loop-shaping is achieved using the describing function (DF)
and performance analysed using linear control sensitivity functions not
applicable for reset control systems, resulting in a significant deviation
between expected and practical results. We overcome this major bottleneck to
the wider adaptation of reset control with two contributions in this paper.
First, we present the extension of frequency-domain tools for reset controllers
in the form of higher-order sinusoidal-input describing functions (HOSIDFs)
providing greater insight into their behaviour. Second, we propose a novel
method which uses the DF and HOSIDFs of the open-loop reset control system for
the estimation of the closed-loop sensitivity functions, establishing for the
first time - the relation between open-loop and closed-loop behaviour of reset
control systems in the frequency domain. The accuracy of the proposed solution
is verified in both simulation and practice on a precision positioning stage
and these results are further analysed to obtain insights into the tuning
considerations for reset controllers
Lynch Syndrome-associated Mutations in MSH2 Alter DNA Repair and Checkpoint Response Functions In Vivo
The DNA mismatch repair (MMR) pathway is essential in maintaining genomic stability through its role in DNA repair and the checkpoint response. Loss of DNA MMR underlies the hereditary cancer disease Lynch Syndrome (LS). Germline mutations in MSH2 account for approximately 40% of LS patients and of these, 18% are missense variants. One important clinical challenge has been discriminating between missense variants that are pathogenic and those that are not. Current analysis of missense mutations in MSH2 is performed using a combination of clinical, biochemical, and functional data; however, suitable cell culture models to test the various functions of the DNA MMR proteins are lacking. Here, we have generated human cell lines stably expressing a subset of MSH2 missense mutants and tested their effect on DNA repair and checkpoint response functions. We have expanded on previous biochemical and functional analyses performed in non-human systems to further understand defects conferred by this subset of single amino acid alterations. The functional characterization of MSH2 missense mutants combined with clinical and biochemical data is essential for appropriate patient management and genetic counseling decisions. ©2010 Wiley-Liss, Inc
Chemical element detection in thin sections of soils with the Laser Microprobe Mass Analyzer (LAMMA 500).
Components from thin sections of soils developed on weathered granite were analysed with the Laser Microprobe Mass Analyzer. Fragments of thin sections were mounted on sandwich grids, and perforated with the laser from the edges inwards (laser milling), using the laser light at grazing incidence. Laser-induced mass spectra of secondary titanium compounds and other constituents in the weathered granite were obtained in this manner. Positive and negative laser desorption mass spectra were recorded with such a speed and accuracy that in spite of the relatively large volume of analysed materials, minute changes in composition could be detected over very short distances. This allowed total chemical element analysis of spots in which titanium compounds concentrated during weathering, giving information on changes in purity of amorphous and semi-crystalline materials at such sites. Characteristic analysis possibilities of the Ion Microprobe Mass Analyzer (IMMA), Laser Microspectral Analyzer (LMA) and Laser Microprobe Mass Analyzer (LAMMA 500) are compared. (Abstract retrieved from CAB Abstracts by CABI’s permission
Geometry Relaxation and Transition State Search throughout Chemical Compound Space with Quantum Machine Learning
We use energies and forces predicted within response operator based quantum
machine learning (OQML) to perform geometry optimization and transition state
search calculations with legacy optimizers. For randomly sampled initial
coordinates of small organic query molecules we report systematic improvement
of equilibrium and transition state geometry output as training set sizes
increase. Out-of-sample S2 reactant complexes and transition state
geometries have been predicted using the LBFGS and the QST2 algorithm with an
RMSD of 0.16 and 0.4 \r{A} -- after training on up to 200 reactant complexes
relaxations and transition state search trajectories from the QMrxn20 data-set,
respectively. For geometry optimizations, we have also considered relaxation
paths up to 5'500 constitutional isomers with sum formula CHO
from the QM9-database. Using the resulting OQML models with an LBFGS optimizer
reproduces the minimum geometry with an RMSD of 0.14~\r{A}. For converged
equilibrium and transition state geometries subsequent vibrational normal mode
frequency analysis indicates deviation from MP2 reference results by on average
14 and 26\,cm, respectively. While the numerical cost for OQML
predictions is negligible in comparison to DFT or MP2, the number of steps
until convergence is typically larger in either case. The success rate for
reaching convergence, however, improves systematically with training set size,
underscoring OQML's potential for universal applicability
Performance and modeling of superconducting ring resonators at millimeter-wave frequencies
Microstrip ring resonators operating at 35 GHz were fabricated from laser ablated YBCO thin films deposited on lanthanum aluminate substrates. They were measured over a range of temperatures and their performance compared to identical resonators made of evaporated gold. Below 60 Kelvin the superconducting strip performed better than the gold, reaching an unloaded Q approximately 1.5 times that of gold at 25 K. A shift in the resonant frequency follows the form predicted by the London equations. The Phenomenological Loss Equivalence Method is applied to the ring resonator and the theoretically calculated Q values are compared to the experimental results
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