460 research outputs found
Solving Quantum Ground-State Problems with Nuclear Magnetic Resonance
Quantum ground-state problems are computationally hard problems; for general
many-body Hamiltonians, there is no classical or quantum algorithm known to be
able to solve them efficiently. Nevertheless, if a trial wavefunction
approximating the ground state is available, as often happens for many problems
in physics and chemistry, a quantum computer could employ this trial
wavefunction to project the ground state by means of the phase estimation
algorithm (PEA). We performed an experimental realization of this idea by
implementing a variational-wavefunction approach to solve the ground-state
problem of the Heisenberg spin model with an NMR quantum simulator. Our
iterative phase estimation procedure yields a high accuracy for the
eigenenergies (to the 10^-5 decimal digit). The ground-state fidelity was
distilled to be more than 80%, and the singlet-to-triplet switching near the
critical field is reliably captured. This result shows that quantum simulators
can better leverage classical trial wavefunctions than classical computers.Comment: 11 pages, 13 figure
The vitamin D grey areas in pediatric primary care. Very low serum 25-hydroxyvitamin D levels in asymptomatic children living in northeastern Italy
The principal questions about the vitamin D topic are far to be resolved: in which children 25-hydroxyvitamin D blood testing is appropriate and how much cholecalciferol should be given in the absence of the test? Analyzing vitamin D status in a group of children cared by a "family pediatrician" in northeastern Italy we noted a high incidence of deficiency in asymptomatic preschool children without risk factors. As routine vitamin D testing is not recommended in the average risk population the supplementation with cholecalciferol represents a "grey area" mostly in pediatric primary care
Cost-effectiveness of a fixed-dose combination of solifenacin and oral controlled adsorption system formulation of tamsulosin in men with lower urinary tract symptoms associated with benign prostatic hyperplasia
The diagnostic strength of the 24-h pad test for self-reported symptoms of urinary incontinence in pregnancy and after childbirth
The clinical impact of incontinence in pregnancy and after childbirth is growing because some studies report the efficacy of physiotherapy in pregnancy and because obstetric choices are supposed to have significant impact on post-reproductive urinary function (Goldberg et al. in Am J Obstet Gynecol 188:1447β1450, 2003). Thus, the need for objective measurement of urinary incontinence in pregnancy is growing. Data on pad testing in pregnancy are lacking. We assessed the clinical relevance of the 24-h pad test during pregnancy and after childbirth, compared with data on self-reported symptoms of urinary incontinence and visual analogue score. According to the receiver operating characteristic curve, the diagnostic value of pad testing for measuring (severity of) self-reported incontinence during pregnancy is not of clinical relevance. However, for the purposes of research, pad tests, combined with subjective/qualitative considerations, play a critical role in allowing comparisons across studies, quantifying the amount of urine loss and establishing a measure of severity
Synthesis of YVO4:Eu3+/YBO3Heteronanostructures with Enhanced Photoluminescence Properties
Novel YVO4:Eu3+/YBO3core/shell heteronanostructures with different shell ratios (SRs) were successfully prepared by a facile two-step method. X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy were used to characterize the heteronanostructures. Photoluminescence (PL) study reveals that PL efficiency of the YVO4:Eu3+nanocrystals (cores) can be improved by the growth of YBO3nanocoatings onto the cores to form the YVO4:Eu3+/YBO3core/shell heteronanostructures. Furthermore, shell ratio plays a critical role in their PL efficiency. The heteronanostructures (SR = 1/7) exhibit the highest PL efficiency; its PL intensity of the5D0β7F2emission at 620 nm is 27% higher than that of the YVO4:Eu3+nanocrystals under the same conditions
Current use and barriers and facilitators for implementation of standardised measures in physical therapy in the Netherlands
In many countries, the need for physical therapists to use standardised measures has been recognised and is recommended in clinical practice guidelines. Research has shown a lack of clinimetric knowledge and clinical application of measurement instruments in daily practice may hamper implementation of these guidelines. The aims of this study are 1) to investigate the current use of measurement instruments by Dutch physical therapists; 2) to investigate the facilitators and barriers in using measurement instruments
Measurement of D-s(+) and D-s(*+) production in B meson decays and from continuum e(+)e(-) annihilation at βs=10.6 GeV
This is the pre-print version of the Article. The official published version can be accessed from the links below. Copyright @ 2002 APSNew measurements of Ds+ and Ds*+ meson production rates from B decays and from qqΜ
continuum events near the Ξ₯(4S) resonance are presented. Using 20.8 fb-1 of data on the Ξ₯(4S) resonance and 2.6 fb-1 off-resonance, we find the inclusive branching fractions B(BβDs+X)=(10.93Β±0.19Β±0.58Β±2.73)% and B(BβDs*+X)=(7.9Β±0.8Β±0.7Β±2.0)%, where the first error is statistical, the second is systematic, and the third is due to the Ds+βΟΟ+ branching fraction uncertainty. The production cross sections Ο(e+e-βDs+X)ΓB(Ds+βΟΟ+)=7.55Β±0.20Β±0.34pb and Ο(e+e-βDs*Β±X)ΓB(Ds+βΟΟ+)=5.8Β±0.7Β±0.5pb are measured at center-of-mass energies about 40 MeV below the Ξ₯(4S) mass. The branching fractions Ξ£B(BβDs(*)+D(*))=(5.07Β±0.14Β±0.30Β±1.27)% and Ξ£B(BβDs*+D(*))=(4.1Β±0.2Β±0.4Β±1.0)% are determined from the Ds(*)+ momentum spectra. The mass difference m(Ds+)-m(D+)=98.4Β±0.1Β±0.3MeV/c2 is also measured.This work was supported by DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF (Germany), INFN (Italy), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from the Swiss NSF, A. P. Sloan Foundation, Research Corporation, and Alexander von Humboldt Foundation
Merging Resource Availability with Isotope Mixing Models: The Role of Neutral Interaction Assumptions
Background: Bayesian mixing models have allowed for the inclusion of uncertainty and prior information in the analysis of trophic interactions using stable isotopes. Formulating prior distributions is relatively straightforward when incorporating dietary data. However, the use of data that are related, but not directly proportional, to diet (such as prey availability data) is often problematic because such information is not necessarily predictive of diet, and the information required to build a reliable prior distribution for all prey species is often unavailable. Omitting prey availability data impacts the estimation of a predator's diet and introduces the strong assumption of consumer ultrageneralism (where all prey are consumed in equal proportions), particularly when multiple prey have similar isotope values. Methodology: We develop a procedure to incorporate prey availability data into Bayesian mixing models conditional on the similarity of isotope values between two prey. If a pair of prey have similar isotope values (resulting in highly uncertain mixing model results), our model increases the weight of availability data in estimating the contribution of prey to a predator's diet. We test the utility of this method in an intertidal community against independently measured feeding rates. Conclusions: Our results indicate that our weighting procedure increases the accuracy by which consumer diets can be inferred in situations where multiple prey have similar isotope values. This suggests that the exchange of formalism for predictive power is merited, particularly when the relationship between prey availability and a predator's diet cannot be assumed for all species in a system.National Science Foundation (NSF) [DEB-0608178]U.S. Environmental Protection AgencyDepartment of EducationSigma XiUniversity of ChicagoFundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)(CAPES) Coordenacao de Aperfeicoamento de Pessoal de Nivel Superiori
One year of smokefree bars and restaurants in New Zealand: Impacts and responses
BACKGROUND: New Zealand introduced a smokefree bars and restaurants policy in December 2004. We reviewed the data available at December 2005 on the main public health, societal and political impacts and responses within New Zealand to the new law. METHODS: Data were collected from publicly available survey reports, and from government departments and interviews. This included data on smoking in bars, attitudes to smokefree bars, bar patronage, socially cued smoking, and perceived rights to smokefree workplaces. RESULTS: The proportion of surveyed bars with smoking occurring decreased from 95% to 3% during July 2004 β April 2005. Between 2004 and 2005, public support for smokefree bars rose from 56% to 69%. In the same period, support for the rights of bar workers to have smokefree workplaces rose from 81% to 91%. During the first ten months of the smokefree bars policy, there were only 196 complaints to officials about smoking in the over 9900 licensed premises. The proportion of smokers who reported that they smoked more than normal at bars, nightclubs, casinos and cafΓ©s halved between 2004 and 2005 (from 58% to 29%). Seasonally adjusted sales in bars and clubs changed little (0.6% increase) between the first three quarters of 2004 and of 2005, while cafΓ© and restaurant sales increased by 9.3% in the same period. Both changes continued existing trends. Compared to the same period in 2004, average employment during the first three quarters of 2005 was up 24% for 'pubs, taverns and bars', up 9% for cafΓ©s/restaurants, and down 8% for clubs (though employment in 'pubs, taverns and bars' may have been affected by unusually high patronage around a major sports-series). The proportion of bar managers who approved of smokefree bars increased from 44% to 60% between November 2004 and May 2005. Bar managers also reported increased agreement with the rights of bar workers and patrons to smokefree environments. The main reported concerns of the national and regional Hospitality Associations, in 2005, were the perceived negative effects on rural and traditional pubs. CONCLUSION: As in other jurisdictions, the introduction of smokefree bars in New Zealand has had positive overall health protection, economic and social effects; in contrast to the predictions of opponents
Distress and quality of life characteristics associated with seeking surgical treatment for stress urinary incontinence
<p>Abstract</p> <p>Background</p> <p>Current research focuses on three variables in evaluating the impact of stress urinary incontinence (SUI) on daily living: severity of incontinence, distress or bother resulting from incontinence, and effect on health related quality of life (HRQoL). Understanding the impact of these variables is important as they are the driving force behind women seeking surgical treatment. Given the importance of HRQoL in determining need for treatment, as well as evaluating treatment success, this review provides an assessment of the degree to which HRQoL is impaired in women seeking surgical treatment.</p> <p>Methods</p> <p>PubMed searches for the terms "quality of life and distress and urinary incontinence" and "quality of life and bother and urinary incontinence" were performed with limits of English, human and female subjects through May 2008. All studies using validated instruments were included. No time limit was placed on the search.</p> <p>Results</p> <p>Of 178 articles retrieved, 21 met the inclusion criteria, and 17 reported methods of scoring. The studies used the Urogenital Distress Inventory (UDI) and the Incontinence Impact Questionnaire (IIQ). Wide ranges of mean and individual levels of severity of symptoms, UDI and IIQ scores were seen among women seeking surgical treatment. Fourteen studies reported baseline and post-surgical treatment distress and QoL data. Statistically significant improvements between baseline and post-surgical UDI and IIQ scores were reported in 12 studies. Reported cure rates ranged from 46% to 97%. Satisfaction with the procedure was reported in 4 studies and ranged from 84% to 91%. A minority of studies reported the relationship between reduction in symptoms and change in HRQoL.</p> <p>Conclusion</p> <p>HRQoL is the main reason women seek surgical treatment for incontinence and surgical treatment leads to a significant improvement in mean HRQoL scores. Assessment of HRQoL has proved less useful in identifying why individual women seek treatment for incontinence. Preliminary work has begun to characterize the interaction between severity of symptoms, distress or bother resulting from these urinary symptoms, impact on HRQoL, and treatment seeking behavior, but further research is needed. Greater standardization in the reporting of results of distress or bother and HRQoL would allow for comparison across studies.</p
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