1,988 research outputs found
Lazy Abstraction-Based Controller Synthesis
We present lazy abstraction-based controller synthesis (ABCS) for
continuous-time nonlinear dynamical systems against reach-avoid and safety
specifications. State-of-the-art multi-layered ABCS pre-computes multiple
finite-state abstractions of varying granularity and applies reactive synthesis
to the coarsest abstraction whenever feasible, but adaptively considers finer
abstractions when necessary. Lazy ABCS improves this technique by constructing
abstractions on demand. Our insight is that the abstract transition relation
only needs to be locally computed for a small set of frontier states at the
precision currently required by the synthesis algorithm. We show that lazy ABCS
can significantly outperform previous multi-layered ABCS algorithms: on
standard benchmarks, lazy ABCS is more than 4 times faster
Optimizing outcomes for patients with severe haemophilia A
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73864/1/j.1365-2516.2007.01552.x.pd
Spherical Relativistic Hartree theory in a Woods-Saxon basis
The Woods-Saxon basis has been suggested to replace the widely used harmonic
oscillator basis for solving the relativistic mean field (RMF) theory in order
to generalize it to study exotic nuclei. As examples, relativistic Hartree
theory is solved for spherical nuclei in a Woods-Saxon basis obtained by
solving either the Schr\"odinger equation or the Dirac equation (labelled as
SRHSWS and SRHDWS, respectively and SRHWS for both). In SRHDWS, the negative
levels in the Dirac Sea must be properly included. The basis in SRHDWS could be
smaller than that in SRHSWS which will simplify the deformed problem. The
results from SRHWS are compared in detail with those from solving the spherical
relativistic Hartree theory in the harmonic oscillator basis (SRHHO) and those
in the coordinate space (SRHR). All of these approaches give identical nuclear
properties such as total binding energies and root mean square radii for stable
nuclei. For exotic nuclei, e.g., Ca, SRHWS satisfactorily reproduces the
neutron density distribution from SRHR, while SRHHO fails. It is shown that the
Woods-Saxon basis can be extended to more complicated situations for exotic
nuclei where both deformation and pairing have to be taken into account.Comment: 12 pages, 9 figure
A systematic review of randomised controlled trials on the effectiveness of exercise programs on lumbo pelvic pain among postnatal women
Background: A substantial number of women tend to be affected by Lumbo Pelvic Pain (LPP) following child birth.
Physical exercise is indicated as a beneficial method to relieve LPP, but individual studies appear to suggest mixed
findings about its effectiveness. This systematic review aimed to synthesise evidence from randomised controlled trials on the effectiveness of exercise on LPP among postnatal women to inform policy, practice and future research.
Methods: A systematic review was conducted of all randomised controlled trials published between January 1990 and July 2014, identified through a comprehensive search of following databases: PubMed, PEDro, Embase, Cinahl, Medline, SPORTDiscus, Cochrane Pregnancy and Childbirth Group’s Trials Register, and electronic libraries of authors’institutions.
Randomised controlled trials were eligible for inclusion if the intervention comprised of postnatal exercise for women
with LPP onset during pregnancy or within 3 months after delivery and the outcome measures included changes in
LPP. Selected articles were assessed using the PEDro Scale for methodological quality and findings were synthesised narratively as meta-analysis was found to be inappropriate due to heterogeneity among included studies.
Results: Four randomised controlled trials were included, involving 251 postnatal women. Three trials were rated as
of ‘good’ methodological quality. All trials, except one, were at low risk of bias. The trials included physical exercise
programs with varying components, differing modes of delivery, follow up times and outcome measures. Intervention
in one trial, involving physical therapy with specific stabilising exercises, proved to be effective in reducing LPP
intensity. An improvement in gluteal pain on the right side was reported in another trial and a significant difference in
pain frequency in another.
Conclusion: Our review indicates that only few randomised controlled trials have evaluated the effectiveness of
exercise on LPP among postnatal women. There is also a great amount of variability across existing trials in the
components of exercise programs, modes of delivery, follow up times and outcome measures. While there is some
evidence to indicate the effectiveness of exercise for relieving LPP, further good quality trials are needed to ascertain
the most effective elements of postnatal exercise programs suited for LPP treatment
Dissociable effects of 5-HT2C receptor antagonism and genetic inactivation on perseverance and learned non-reward in an egocentric spatial reversal task
Cognitive flexibility can be assessed in reversal learning tests, which are sensitive to modulation of 5-HT2C receptor (5-HT2CR) function. Successful performance in these tests depends on at least two dissociable cognitive mechanisms which may separately dissipate associations of previous positive and negative valence. The first is opposed by perseverance and the second by learned non-reward. The current experiments explored the effect of reducing function of the 5-HT2CR on the cognitive mechanisms underlying egocentric reversal learning in the mouse. Experiment 1 used the 5-HT2CR antagonist SB242084 (0.5 mg/kg) in a between-groups serial design and Experiment 2 used 5-HT2CR KO mice in a repeated measures design. Animals initially learned to discriminate between two egocentric turning directions, only one of which was food rewarded (denoted CS+, CS−), in a T- or Y-maze configuration. This was followed by three conditions; (1) Full reversal, where contingencies reversed; (2) Perseverance, where the previous CS+ became CS− and the previous CS− was replaced by a novel CS+; (3) Learned non-reward, where the previous CS− became CS+ and the previous CS+ was replaced by a novel CS-. SB242084 reduced perseverance, observed as a decrease in trials and incorrect responses to criterion, but increased learned non-reward, observed as an increase in trials to criterion. In contrast, 5-HT2CR KO mice showed increased perseverance. 5-HT2CR KO mice also showed retarded egocentric discrimination learning. Neither manipulation of 5-HT2CR function affected performance in the full reversal test. These results are unlikely to be accounted for by increased novelty attraction, as SB242084 failed to affect performance in an unrewarded novelty task. In conclusion, acute 5-HT2CR antagonism and constitutive loss of the 5-HT2CR have opposing effects on perseverance in egocentric reversal learning in mice. It is likely that this difference reflects the broader impact of 5HT2CR loss on the development and maintenance of cognitive function
Josephson supercurrent through a topological insulator surface state
Topological insulators are characterized by an insulating bulk with a finite
band gap and conducting edge or surface states, where charge carriers are
protected against backscattering. These states give rise to the quantum spin
Hall effect without an external magnetic field, where electrons with opposite
spins have opposite momentum at a given edge. The surface energy spectrum of a
threedimensional topological insulator is made up by an odd number of Dirac
cones with the spin locked to the momentum. The long-sought yet elusive
Majorana fermion is predicted to arise from a combination of a superconductor
and a topological insulator. An essential step in the hunt for this emergent
particle is the unequivocal observation of supercurrent in a topological phase.
Here, we present the first measurement of a Josephson supercurrent through a
topological insulator. Direct evidence for Josephson supercurrents in
superconductor (Nb) - topological insulator (Bi2Te3) - superconductor e-beam
fabricated junctions is provided by the observation of clear Shapiro steps
under microwave irradiation, and a Fraunhofer-type dependence of the critical
current on magnetic field. The dependence of the critical current on
temperature and length shows that the junctions are in the ballistic limit.
Shubnikov-de Haas oscillations in magnetic fields up to 30 T reveal a
topologically non-trivial two-dimensional surface state. We argue that the
ballistic Josephson current is hosted by this surface state despite the fact
that the normal state transport is dominated by diffusive bulk conductivity.
The lateral Nb-Bi2Te3-Nb junctions hence provide prospects for the realization
of devices supporting Majorana fermions
Structured feedback on students’ concept maps: the proverbial path to learning?
Good conceptual knowledge is an essential requirement for health professions students, in that they are required to apply concepts learned in the classroom to a variety of different contexts. However, the use of traditional methods of assessment limits the educator’s ability to correct students’ conceptual knowledge prior to altering the educational context. Concept mapping (CM) is an educational tool for evaluating conceptual knowledge, but little is known about its use in facilitating the development of richer knowledge frameworks. In addition, structured feedback has the potential to develop good conceptual knowledge. The purpose of this study was to use Kinchin’s criteria to assess the impact of structured feedback on the graphical complexity of CM’s by observing the development of richer knowledge frameworks. Fifty-eight physiotherapy students created CM’s targeting the integration of two knowledge domains within a case-based teaching paradigm. Each student received one round of structured feedback that addressed correction, reinforcement, forensic diagnosis, benchmarking, and longitudinal development on their CM’s prior to the final submission. The concept maps were categorized according to Kinchin’s criteria as either Spoke, Chain or Net representations, and then evaluated against defined traits of meaningful learning. The inter-rater reliability of categorizing CM’s was good. Pre-feedback CM’s were predominantly Chain structures (57%), with Net structures appearing least often. There was a significant reduction of the basic Spoke- structured CMs (P = 0.002) and a significant increase of Net-structured maps (P < 0.001) at the final evaluation (post-feedback). Changes in structural complexity of CMs appeared to be indicative of broader knowledge frameworks as assessed against the meaningful learning traits. Feedback on CM’s seemed to have contributed towards improving conceptual knowledge and correcting naive conceptions of related knowledge. Educators in medical education could therefore consider using CM’s to target individual student development
Single-Particle and Collective Motion for Proton-Rich Nuclei on the Astrophysical rp-Process Path
Based on available experimental data, a new set of Nilsson parameters is
proposed for proton-rich nuclei with proton or neutron numbers . The resulting single-particle spectra are compared with those from
relativistic and non-relativistic mean field theories. Collective excitations
in some even--even proton-rich nuclei in the upper shell are investigated
using the Projected Shell Model with the new Nilsson basis. It is found that
the regular bands are sharply disturbed by band crossings involving
neutrons and protons. Physical quantities for exploring the nature of the band
disturbance and the role of the single-particle are predicted, which
may be tested by new experiments with radioactive beams.Comment: 4 pages, 3 figures, accepted by Phys. Rev. C, Rapid Communicatio
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