2,126 research outputs found
On the Groenewold-Van Hove problem for R^{2n}
We discuss the Groenewold-Van Hove problem for R^{2n}, and completely solve
it when n = 1. We rigorously show that there exists an obstruction to
quantizing the Poisson algebra of polynomials on R^{2n}, thereby filling a gap
in Groenewold's original proof without introducing extra hypotheses. Moreover,
when n = 1 we determine the largest Lie subalgebras of polynomials which can be
unambiguously quantized, and explicitly construct all their possible
quantizations.Comment: 15 pages, Latex. Error in the proof of Prop. 3 corrected; minor
rewritin
Pelvic floor muscle function in a general population of women with and without pelvic organ prolapse
This study aims to examine the relationship between pelvic floor muscle function (PFMF) and pelvic organ prolapse (POP) in a general female population. Cross-sectional study on women aged 45-85 years. Validated questionnaires were used to assess pelvic floor muscle function. POP and PFMF were evaluated with vaginal examination. For statistical analysis chi-squared test for trend and analysis of variance were used. Response rate to the questionnaire was 62.7% (1,869/2,979). No significant differences were found in muscle strength and endurance during voluntary muscle contraction between the POP stages. Women with POP stages I and II were significantly less able to achieve effective involuntary muscle contraction during coughing (38.3% and 37.7%) than women without POP (75.2%). Involuntary contraction of the PFM during coughing (that resulted in stabilization of the perineum) was significantly weaker in the women with POP stage I and II than in the women without POP
NMscatt: a program for calculating inelastic scattering from large biomolecular systems using classical force-field simulations
Computational tools for normal mode analysis, which are widely used in
physics and materials science problems, are designed here in a single package
called NMscatt (Normal Modes & scattering) that allows arbitrarily large
systems to be handled. The package allows inelastic neutron and X-ray
scattering observables to be calculated, allowing comparison with experimental
data produced at large scale facilities. Various simplification schemes are
presented for analysing displacement vectors, which are otherwise too
complicated to understand in very large systems.Comment: 13 pages, 5 figures, preprint submitted to Computer Physics
Communication
The usefulness of offering 24/7 online support within a wider mix of professional services for people with intellectual and developmental disabilities living independently : a qualitative, multiple case study
Service organizations for people with intellectual and developmental disabilities (IDD) increasingly use telecare applications to improve their services. This study explored the usefulness of offering the 24/7 online support service DigiContact within a broader mix of professional services for people with IDD living independently. We employed a qualitative multiple case study, in which the cases of nine online support users were reconstructed through semistructured interviews with both support users and their case workers. Thematic analysis showed that online support was used as an addition to regular onsite support to enable a more tailor-made delivery of professional supports. Online support can be valuable for its users by increasing the accessibility of professional support and creating opportunities for more self-direction in support
Comparison of ecosystem processes in a woodland and prairie pond with different hydroperiods
Shallow lakes and ponds constitute a significant number of water bodies worldwide. Many are heterotrophic, indicating that they are likely net contributors to global carbon cycling. Climate change is likely to have important impacts on these waterbodies. In this study, we examined two small Minnesota ponds; a permanent woodland pond and a temporary prairie pond. The woodland pond had lower levels of phosphorus and phytoplankton than the prairie pond. Using the open water oxygen method, we found the prairie pond typically had a higher level of gross primary production (GPP) and respiration (R) than the woodland pond, although the differences between the ponds varied with season. Despite the differences in GPP and R between the ponds the net ecosystem production was similar with both being heterotrophic. Since abundant small ponds may play an important role in carbon cycling and are likely to undergo changes in temperature and hydroperiod associated with climate change, understanding pond metabolism is critical in predicting impacts and designing management schemes to mitigate changes
Orthostatic blood pressure recovery patterns in suspected syncope in the emergency department
INTRODUCTION: Orthostasis is a frequent trigger for (pre)syncope but some forms of orthostatic (pre)syncope have a worse prognosis than others. Routine assessment of orthostatic BP in the ED can detect classic orthostatic hypotension, but often misses these other forms of orthostatic (pre)syncope. This study aimed to determine the frequency of abnormal orthostatic BP recovery patterns in patients with (pre)syncope by using continuous non-invasive BP monitoring. METHODS: We performed a prospective cohort study in suspected patients with (pre)syncope in the ED of a tertiary care teaching hospital between January and August 2014. Orthostatic BP was measured during the active lying-to-standing test with Nexfin, a continuous non-invasive finger arterial pressure measurement device. Orthostatic BP recovery patterns were defined as normal BP recovery, initial orthostatic hypotension, delayed BP recovery, classic orthostatic hypotension and reflex-mediated hypotension. RESULTS: Of 116 patients recruited, measurements in 111 patients (age 63 years, 51% male) were suitable for analysis. Classic orthostatic hypotension was the most prevalent abnormal BP pattern (19%), but only half of the patients received a final diagnosis of orthostatic hypotension. Initial orthostatic hypotension and delayed BP recovery were present in 20% of the patients with (pre)syncope of whom 45% were diagnosed as unexplained syncope. Reflex-mediated hypotension was present in 4% of the patients. CONCLUSION: Continuous non-invasive BP measurement can potentially identify more specific and concerning causes of orthostatic (pre)syncope. Correct classification is important because of different short-term and long-term clinical implications
Obtaining control of cell surface functionalizations via Pre-targeting and Supramolecular host guest interactions
Measurement of one-particle correlations and momentum distributions for trapped 1D gases
van Hove's theory of scattering of probe particles by a macroscopic target is
generalized so as to relate the differential cross section for atomic ejection
via stimulated Raman transitions to one-particle momentum-time correlations and
momentum distributions of 1D trapped gases. This method is well suited to
probing the longitudinal momentum distributions of 1D gases in situ, and
examples are given for bosonic and fermionic atoms.Comment: 4 pages, 2 .eps figure
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