UV frequency metrology on CO (a3Pi); isotope effects and sensitivity to a variation of the proton-to-electron mass ratio

UV frequency metrology has been performed on the a3Pi - X1Sigma+ (0,0) band of various isotopologues of CO using a frequency-quadrupled injection-seeded narrow-band pulsed Titanium:Sapphire laser referenced to a frequency comb laser. The band origin is determined with an accuracy of 5 MHz (delta \nu / \nu = 3 * 10^-9), while the energy differences between rotational levels in the a3Pi state are determined with an accuracy of 500 kHz. From these measurements, in combination with previously published radiofrequency and microwave data, a new set of molecular constants is obtained that describes the level structure of the a3Pi state of 12C16O and 13C16O with improved accuracy. Transitions in the different isotopologues are well reproduced by scaling the molecular constants of 12C16O via the common mass-scaling rules. Only the value of the band origin could not be scaled, indicative of a breakdown of the Born-Oppenheimer approximation. Our analysis confirms the extreme sensitivity of two-photon microwave transitions between nearly-degenerate rotational levels of different Omega-manifolds for probing a possible variation of the proton-to-electron mass ratio, \mu=m_p/m_e, on a laboratory time scale

Muon spin rotation and relaxation in the superconducting ferromagnet UCoGe

We report zero-field muon spin rotation and relaxation measurements on the superconducting ferromagnet UCoGe. Weak itinerant ferromagnetic order is detected by a spontaneous muon spin precession frequency below the Curie temperature $T_C = 3$ K. The $\mu^+$ precession frequency persists below the bulk superconducting transition temperature $T_{sc} = 0.5$ K, where it measures a local magnetic field $B_{loc} = 0.015$ T. The amplitude of the $\mu$SR signal provides unambiguous proof for ferromagnetism present in the whole sample volume. We conclude ferromagnetism coexists with superconductivity on the microscopic scale.Comment: 4 pages, 3 figures, accepted for publication in PR

Simultaneous suppression of ferromagnetism and superconductivity in UCoGe by Si substitution

We investigate the effect of substituting Si for Ge in the ferromagnetic superconductor UCoGe. Dc-magnetization, ac-susceptibility and electrical resistivity measurements on polycrystalline UCoGe$_{1-x}$Si$_x$ samples show that ferromagnetic order and superconductivity are progressively depressed with increasing Si content and simultaneously vanish at a critical concentration $x_{cr} \simeq 0.12$. The non-Fermi liquid temperature variation in the electrical resistivity near $x_{cr}$ and the smooth depression of the ordered moment point to a continuous ferromagnetic quantum phase transition. Superconductivity is confined to the ferromagnetic phase, which provides further evidence for magnetically mediated superconductivity.Comment: 5 pages, 4 figures, accepted for publication in PR

Role of charge patches in ion guiding through nanocapillaries in a PET polymer

We studied the dynamic properties of ion guiding through nanocapillaries in insulating polyethylene terephthalate (PET). The angular distribution of the transmitted ions was measured as a function of time. The temporal evolution of the angular transmission profiles was acquired for the capillary diameters of 200 and 400 nm. The tilt angle was varied from 0° to 6.5°. The transmission profiles exhibit significant changes in position as time varies. This observation is explained by the formation of temporary charge patches produced in the interior of the capillary besides the primary charge patch created in the entrance region.</p

Alendroninezuur effectiever dan alfacalcidol voor preventie van osteoporose bij patiënten met een reumatische ziekte die starten met glucocorticoïdtherapie

OBJECTIVE: To compare the effects of alendronate and alfacalcidol in the prevention ofglucocorticoid-related osteoporosis in patients with a rheumatic disease. DESIGN: Randomised, double-blind, double-placebo clinical trial (www. clinicaltrials.gov; number: NCT00138983). METHODS: A total of 201 patients with rheumatic disease who were starting glucocorticoid treatment at a daily dose that was equivalent to at least 7.5 mg of prednisone were randomised to alendronate (10 mg) and a placebo capsule ofalfacalcidol daily (n = 100) or alfacalcidol (1 microg) and a placebo tablet ofalendronate daily (n = 101) for 18 months. Primary outcome was change in lumbar spine bone mineral density at 18 months. The main secondary outcome was the incidence of morphometrically confirmed vertebral deformities. RESULTS: Overall, 163 patients completed the study. The bone mineral density of the lumbar spine increased by 2.1% (95% CI: 1.1-3.1) in the alendronate group and decreased by 1.9% (95% CI: -3.I--0.7) in the alfacalcidol group. At 18 months the mean difference in change in bone mineral density between the two groups was 4.0% (95% CI: 2.4-5-5). Three patients in the alendronate group had a new vertebral deformity, compared with 8 patients in the alfacalcidol group, including 5 symptomatic vertebral fractures in 3 patients; the hazard ratio was 0.4 (95% CI: 0.1-1.4). CONCLUSION: Alendronate was more effective than alfacalcidol in preventing glucocorticoid-induced bone loss during this 18-month trial in patients with rheumatic diseases who were starting glucocorticoid treatment

An alternative order parameter for the 4-state Potts model

We have investigated the dynamic critical behavior of the two-dimensional 4-state Potts model using an alternative order parameter first used by Vanderzande [J. Phys. A: Math. Gen. \textbf{20}, L549 (1987)] in the study of the Z(5) model. We have estimated the global persistence exponent $\theta_g$ by following the time evolution of the probability $P(t)$ that the considered order parameter does not change its sign up to time $t$. We have also obtained the critical exponents $\theta$, $z$, $\nu$, and $\beta$ using this alternative definition of the order parameter and our results are in complete agreement with available values found in literature.Comment: 6 pages, 6 figure