Transverse laser cooling of a thermal atomic beam of dysprosium

A thermal atomic beam of dysprosium (Dy) atoms is cooled using the $4f^{10}6s^2 (J=8) \to 4f^{10}6s6p (J=9)$ transition at 421 nm. The cooling is done via a standing light wave orthogonal to the atomic beam. Efficient transverse cooling to the Doppler limit is demonstrated for all observable isotopes of dysprosium. Branching ratios to metastable states are demonstrated to be $<5\times10^{-4}$. A scheme for enhancement of the nonzero-nuclear-spin-isotope cooling, as well as a method for direct identification of possible trap states, is proposed.Comment: 5 pages, 4 figures v2: 7 pages, 7 figure

The EVerT2 (Effective Verruca Treatments) trial : a randomised controlled trial of needling versus nonsurgical debridement for the treatment of plantar verrucae

Background: Verrucae are a common foot skin pathology which can in some cases persist for many years. Plantar verrucae can be unsightly and painful. There are a range of treatment options including needling. Objectives: The EVerT2 trial aimed to evaluate the clinical and cost effectiveness of the needling procedure for the treatment of plantar verrucae, relative to callus debridement. Methods: This single centre randomised controlled trial recruited 60 participants (aged 18 years and over with a plantar verruca). Participants were randomised 1:1 to the intervention group (needling) or the control group (debridement of the overlying callus). The primary outcome was clearance of the index verruca at 12 weeks after randomisation. Secondary outcomes include recurrence of the verruca; clearance of all verrucae; number of verrucae; size of the index verruca; pain; and participant satisfaction at 12 and 24 weeks. A cost-effectiveness analysis was carried out from the NHS perspective over 12 weeks. Results: Sixty eligible patients were randomised (needling group n=29, 48.3%; debridement group n=31, 51.7%) and 53 were included in the primary analysis (needling n=28, 96.6%; debridement n=25, 80.7%). Clearance of the index verruca occurred in 8 (15.1%) participants (needling n=4, 14.3%; debridement n=4, 16.0%, p=0.86). The needling intervention costs were on average £14.33 (95% CI 5.32 to 23.35) more per patient than debridement. Conclusions: There is no evidence that the needling technique is more clinically or cost effective than callus debridement. The results show a significant improvement in pain outcomes after needling compared to the debridement treatment alone. Trial registration number: Current Controlled Trials ISRCTN1642944

Collisional perturbation of radio-frequency E1 transitions in an atomic beam of dysprosium

We have studied collisional perturbations of radio-frequency (rf) electric-dipole (E1) transitions between the nearly degenerate opposite-parity levels in atomic dysprosium (Dy) in the presence of 10 to 80 $\mu$Torr of H$_\text{2}$, N$_\text{2}$, He, Ar, Ne, Kr, and Xe. Collisional broadening and shift of the resonance, as well as the attenuation of the signal amplitude are observed to be proportional to the foreign-gas density with the exception of H$_2$ and Ne, for which no shifts were observed. Corresponding rates and cross sections are presented. In addition, rates and cross sections for O$_2$ are extracted from measurements using air as foreign gas. The primary motivation for this study is the need for accurate determination of the shift rates, which are needed in a laboratory search for the temporal variation of the fine-structure constant [A. T. Nguyen, D. Budker, S. K. Lamoreaux, and J. R. Torgerson, Phys. Rev. A \textbf{69}, 22105 (2004)].Comment: 11 pages, 8 figure

Patient level pooled analysis of 68,500 patients from seven major vitamin D fracture trials in the US and Europe

Objectives To identify participants’ characteristics that influence the anti-fracture efficacy of vitamin D or vitamin D plus calcium with respect to any fracture, hip fracture, and clinical vertebral fracture and to assess the influence of dosing regimens and co-administration of calcium. Design Individual patient data analysis using pooled data from randomised trials. Data sources Seven major randomised trials of vitamin D with calcium or vitamin D alone, yielding a total of 68 517 participants (mean age 69.9 years, range 47-107 years, 14.7% men). Study selection Studies included were randomised studies with at least one intervention arm in which vitamin D was given, fracture as an outcome, and at least 1000 participants. Data synthesis Logistic regression analysis was used to identify significant interaction terms, followed by Cox’s proportional hazards models incorporating age, sex, fracture history, and hormone therapy and bisphosphonate use. Results Trials using vitamin D with calcium showed a reduced overall risk of fracture (hazard ratio 0.92, 95% confidence interval 0.86 to 0.99, P=0.025) and hip fracture (all studies: 0.84, 0.70 to 1.01, P=0.07; studies using 10 μg of vitamin D given with calcium: 0.74, 0.60 to 0.91, P=0.005). For vitamin D alone in daily doses of 10 μg or 20 μg, no significant effects were found. No interaction was found between fracture history and treatment response, nor any interaction with age, sex, or hormone replacement therapy. Conclusion This individual patient data analysis indicates that vitamin D given alone in doses of 10-20 μg is not effective in preventing fractures. By contrast, calcium and vitamin D given together reduce hip fractures and total fractures, and probably vertebral fractures, irrespective of age, sex, or previous fractures.The WHI program is funded by the National Heart, Lung, and Blood Institute, National Institutes of Health, US Department of Health and Human Services through contracts N01WH22110, 24152, 32100-2, 32105-6, 32108-9, 32111-13, 32115, 32118-32119, 32122, 42107-26, 42129-32, and 44221. AA acknowledges personal funding from the UK Medical Research Council and Chief Scientist Office of the Scottish Government Health Directorates

About entanglement properties of kaons and tests of hidden variables models

In this letter we discuss entanglement properties of neutral kaons systems and their use for testing local realism. In particular we show that, as previous proposals, also a scheme recently suggested for performing a test of hidden variable theories against standard quantum mechanics cannot be conclusive

Implementing Unitarity in Perturbation Theory

Unitarity cannot be perserved order by order in ordinary perturbation theory because the constraint UU^\dagger=\1 is nonlinear. However, the corresponding constraint for $K=\ln U$, being $K=-K^\dagger$, is linear so it can be maintained in every order in a perturbative expansion of $K$. The perturbative expansion of $K$ may be considered as a non-abelian generalization of the linked-cluster expansion in probability theory and in statistical mechanics, and possesses similar advantages resulting from separating the short-range correlations from long-range effects. This point is illustrated in two QCD examples, in which delicate cancellations encountered in summing Feynman diagrams of are avoided when they are calculated via the perturbative expansion of $K$. Applications to other problems are briefly discussed.Comment: to appear in Phys. Rev.

Muslim communities learning about second-hand smoke (MCLASS): Study protocol for a pilot cluster randomised controlled trial

Background: In the UK, 40% of Bangladeshi and 29% of Pakistani men smoke cigarettes regularly compared to the national average of 24%. As a consequence, second-hand smoking is also widespread in their households which is a serious health hazard to non-smokers, especially children. Smoking restrictions in households can help reduce exposure to second-hand smoking. This is a pilot trial of 'Smoke Free Homes', an educational programme which has been adapted for use by Muslim faith leaders, in an attempt to find an innovative solution to encourage Pakistani- and Bangladeshi-origin communities to implement smoking restrictions in their homes. The primary objectives for this pilot trial are to establish the feasibility of conducting such an evaluation and provide information to inform the design of a future definitive study.Methods/Design: This is a pilot cluster randomised controlled trial of 'Smoke Free Homes', with an embedded preliminary health economic evaluation and a qualitative analysis. The trial will be carried out in around 14 Islamic religious settings. Equal randomisation will be employed to allocate each cluster to a trial arm. The intervention group will be offered the Smoke Free Homes package (Smoke Free Homes: a resource for Muslim religious teachers), trained in its use, and will subsequently implement the package in their religious settings. The remaining clusters will not be offered the package until the completion of the study and will form the control group. At each cluster, we aim to recruit around 50 households with at least one adult resident who smokes tobacco and at least one child or a non-smoking adult. Households will complete a household survey and a non-smoking individual will provide a saliva sample which will be tested for cotinine. All participant outcomes will be measured before and after the intervention period in both arms of the trial. In addition, a purposive sample of participants and religious leaders/teachers will take part in interviews and focus groups.Discussion: The results of this pilot study will inform the protocol for a definitive trial

Testing of quantum phase in matter wave optics

Various phase concepts may be treated as special cases of the maximum likelihood estimation. For example the discrete Fourier estimation that actually coincides with the operational phase of Noh, Fouge`res and Mandel is obtained for continuous Gaussian signals with phase modulated mean.Since signals in quantum theory are discrete, a prediction different from that given by the Gaussian hypothesis should be obtained as the best fit assuming a discrete Poissonian statistics of the signal. Although the Gaussian estimation gives a satisfactory approximation for fitting the phase distribution of almost any state the optimal phase estimation offers in certain cases a measurable better performance. This has been demonstrated in neutron--optical experiment.Comment: 8 pages, 4 figure

Non-maximally entangled states: production, characterization and utilization

Using a spontaneous-downconversion photon source, we produce true non-maximally entangled states, i.e., without the need for post-selection. The degree and phase of entanglement are readily tunable, and are characterized both by a standard analysis using coincidence minima, and by quantum state tomography of the two-photon state. Using the latter, we experimentally reconstruct the reduced density matrix for the polarization. Finally, we use these states to measure the Hardy fraction, obtaining a result that is $122 \sigma$ from any local-realistic result.Comment: 4 pages, 4 figures. To appear in Phys. Rev. Let

Thermal correction to the Casimir force, radiative heat transfer, and an experiment

The low-temperature asymptotic expressions for the Casimir interaction between two real metals described by Leontovich surface impedance are obtained in the framework of thermal quantum field theory. It is shown that the Casimir entropy computed using the impedance of infrared optics vanishes in the limit of zero temperature. By contrast, the Casimir entropy computed using the impedance of the Drude model attains at zero temperature a positive value which depends on the parameters of a system, i.e., the Nernst heat theorem is violated. Thus, the impedance of infrared optics withstands the thermodynamic test, whereas the impedance of the Drude model does not. We also perform a phenomenological analysis of the thermal Casimir force and of the radiative heat transfer through a vacuum gap between real metal plates. The characterization of a metal by means of the Leontovich impedance of the Drude model is shown to be inconsistent with experiment at separations of a few hundred nanometers. A modification of the impedance of infrared optics is suggested taking into account relaxation processes. The power of radiative heat transfer predicted from this impedance is several times less than previous predictions due to different contributions from the transverse electric evanescent waves. The physical meaning of low frequencies in the Lifshitz formula is discussed. It is concluded that new measurements of radiative heat transfer are required to find out the adequate description of a metal in the theory of electromagnetic fluctuations.Comment: 19 pages, 4 figures. svjour.cls is used, to appear in Eur. Phys. J.