We present the first experimental realization of coherent Bragg scattering off a one-dimensional system-two strings of atoms strongly coupled to a single photonic mode-realized by trapping atoms in ...the evanescent field of a tapered optical fiber, which also guides the probe light. We report nearly 12% power reflection from strings containing only about 1000 cesium atoms, an enhancement of 2 orders of magnitude compared to reflection from randomly positioned atoms. This result paves the road towards collective strong coupling in 1D atom-photon systems. Our approach also allows for a straightforward fiber connection between several distant 1D atomic crystals.
The mass of an atom incorporates all its constituents and their interactions. The difference between the mass of an atom and the sum of its building blocks (the binding energy) is a manifestation of ...Einstein’s famous relation E = mc2. The binding energy determines the energy available for nuclear reactions and decays (and thus the creation of elements by stellar nucleosynthesis), and holds the key to the fundamental question of how heavy the elements can be. Superheavy elements have been observed in challenging production experiments, but our present knowledge of the binding energy of these nuclides is based only on the detection of their decay products. The reconstruction from extended decay chains introduces uncertainties that render the interpretation difficult. Here we report direct mass measurements of trans-uranium nuclides. Located at the farthest tip of the actinide species on the proton number–neutron number diagram, these nuclides represent the gateway to the predicted island of stability. In particular, we have determined the mass values of 252-254No (atomic number 102) with the Penning trap mass spectrometer SHIPTRAP. The uncertainties are of the order of 10 keV/c2 (representing a relative precision of 0.05 p.p.m.), despite minute production rates of less than one atom per second. Our experiments advance direct mass measurements by ten atomic numbers with no loss in accuracy, and provide reliable anchor points en route to the island of stability.
At the Helmholtz center GSI, PHELIX (Petawatt High Energy Laser for heavy Ion eXperiments) has been commissioned for operation in stand-alone mode and, in combination with ions accelerated up to an ...energy of 13 MeV/u by the heavy ion accelerator UNILAC. The combination of PHELIX with the heavy-ion beams available at GSI enables a large variety of unique experiments. Novel research opportunities are spanning from the study of ion–matter interaction, through challenging new experiments in atomic physics, nuclear physics, and astrophysics, into the field of relativistic plasma physics.
Selective digestive tract decontamination (SDD) and selective oropharyngeal decontamination (SOD) are infection-prevention measures used in the treatment of some patients in intensive care, but ...reported effects on patient outcome are conflicting.
We evaluated the effectiveness of SDD and SOD in a crossover study using cluster randomization in 13 intensive care units (ICUs), all in The Netherlands. Patients with an expected duration of intubation of more than 48 hours or an expected ICU stay of more than 72 hours were eligible. In each ICU, three regimens (SDD, SOD, and standard care) were applied in random order over the course of 6 months. Mortality at day 28 was the primary end point. SDD consisted of 4 days of intravenous cefotaxime and topical application of tobramycin, colistin, and amphotericin B in the oropharynx and stomach. SOD consisted of oropharyngeal application only of the same antibiotics. Monthly point-prevalence studies were performed to analyze antibiotic resistance.
A total of 5939 patients were enrolled in the study, with 1990 assigned to standard care, 1904 to SOD, and 2045 to SDD; crude mortality in the groups at day 28 was 27.5%, 26.6%, and 26.9%, respectively. In a random-effects logistic-regression model with age, sex, Acute Physiology and Chronic Health Evaluation (APACHE II) score, intubation status, and medical specialty used as covariates, odds ratios for death at day 28 in the SOD and SDD groups, as compared with the standard-care group, were 0.86 (95% confidence interval CI, 0.74 to 0.99) and 0.83 (95% CI, 0.72 to 0.97), respectively.
In an ICU population in which the mortality rate associated with standard care was 27.5% at day 28, the rate was reduced by an estimated 3.5 percentage points with SDD and by 2.9 percentage points with SOD. (Controlled Clinical Trials number, ISRCTN35176830.)
We present a new experimental value for the magnetic moment of the electron bound in hydrogenlike carbon (12C5+): g(exp) = 2.001 041 596 (5). This is the most precise determination of an atomic g(J) ...factor so far. The experiment was carried out on a single 12C5+ ion stored in a Penning trap. The high accuracy was made possible by spatially separating the induction of spin flips and the analysis of the spin direction. The current theoretical value amounts to g(th) = 2.001 041 591 (7). Together experiment and theory test the bound-state QED contributions to the g(J) factor of a bound electron to a precision of 1%.
Ramsey's method of separated oscillatory fields is applied to the excitation of the cyclotron motion of short-lived ions in a Penning trap to improve the precision of their measured mass values. The ...theoretical description of the extracted ion-cyclotron-resonance line shape is derived and its correctness demonstrated experimentally by measuring the mass of the short-lived 38Ca nuclide with an uncertainty of 1.1 x 10(-8) using the Penning trap mass spectrometer ISOLTRAP at CERN. The mass of the superallowed beta emitter 38Ca contributes for testing the theoretical corrections of the conserved-vector-current hypothesis of the electroweak interaction. It is shown that the Ramsey method applied to Penning trap mass measurements yields a statistical uncertainty similar to that obtained by the conventional technique but 10 times faster. Thus the technique is a new powerful tool for high-precision mass measurements.
Addition of inhaled iloprost to bosentan may have beneficial effects in patients with idiopathic pulmonary arterial hypertension (IPAH). A multicentre, open, randomised, controlled trial was ...performed to assess the safety and efficacy of inhaled iloprost in patients with IPAH who had already been treated with bosentan. The trial was terminated early after a futility analysis predicted failure with respect to the predetermined sample size. At that time, 40 patients were randomised to receive either bosentan alone (control group) or bosentan plus inhaled iloprost (combination group) for a 12-week period. The primary end-point, change in 6-min walking distance, was not met (mean changes +1 m and -9 m in the control and combination group, respectively). These results may have been skewed by three outliers in the iloprost group who presented with severe clinical worsening. None of the secondary end-points including functional class, peak oxygen uptake, and time to clinical worsening differed significantly between groups. The current study failed to show a positive effect of adding inhaled iloprost to bosentan in idiopathic pulmonary arterial hypertension patients. Further studies involving larger sample sizes and long-term follow-up are needed to determine the efficacy of adding inhaled iloprost to bosentan in patients with idiopathic pulmonary arterial hypertension.
The masses of ten proton-rich nuclides, including the N=Z+1 nuclides ⁸⁵Mo and ⁸⁷Tc, were measured with the Penning trap mass spectrometer SHIPTRAP. Compared to the Atomic Mass Evaluation 2003 a ...systematic shift of the mass surface by up to 1.6 MeV is observed causing significant abundance changes of the ashes of astrophysical x-ray bursts. Surprisingly low α separation energies for neutron-deficient Mo and Tc are found, making the formation of a ZrNb cycle in the rp process possible. Such a cycle would impose an upper temperature limit for the synthesis of elements beyond Nb in the rp process.
A possibility for a determination of the fine structure constant in experiments on the bound-electron g-factor is examined. It is found that studying a specific difference of the g-factors of B- and ...H-like ions of the same spinless isotope in the Pb region to the currently accessible experimental accuracy of 7 x 10(-10) would lead to a determination of the fine structure constant to an accuracy which is better than that of the currently accepted value. Further improvements of the experimental and theoretical accuracy could provide a value of the fine structure constant which is several times more precise than the currently accepted one.
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