A molecular mechanism for the water-hydroxyl balance during wetting of TiO2

We show that the formation of the wetting layer and the experimentally observed continuous shift of the H2O-OH balance towards molecular water at increasing coverage on a TiO2(110) surface can be rationalized on a molecular level. The mechanism is based on the initial formation of stable hydroxyl pairs, a repulsive interaction between these pairs and an attractive interaction with respect to water molecules. The experimental data are obtained by synchrotron radiation photoelectron spectroscopy and interpreted with the aid of density functional theory calculations and Monte Carlo simulations

Low-energy Coulomb excitation of 62^{62}Fe and 62^{62}Mn following in-beam decay of 62^{62}Mn

Sub-barrier Coulomb-excitation was performed on a mixed beam of $^{62}$Mn and $^{62}$Fe, following in-trap $\beta^{-}$ decay of $^{62}$Mn at REX-ISOLDE, CERN. The trapping and charge breeding times were varied in order to alter the composition of the beam, which was measured by means of an ionisation chamber at the zero-angle position of the Miniball array. A new transition was observed at 418~keV, which has been tentatively associated to a $(2^{+},3^{+})\rightarrow1^{+}_{g.s.}$ transition. This fixes the relative positions of the $\beta$-decaying $4^{+}$ and $1^{+}$ states in $^{62}$Mn for the first time. Population of the $2^{+}_{1}$ state was observed in $^{62}$Fe and the cross-section determined by normalisation to the $^{109}$Ag target excitation, confirming the $B(E2)$ value measured in recoil-distance lifetime experiments.Comment: 9 pages, 10 figure

Physics and chemistry of hydrogen in the vacancies of semiconductors

Hydrogen is well known to cause electrical passivation of lattice vacancies in semiconductors. This effect follows from the chemical passivation of the dangling bonds. Recently it was found that H in the carbon vacancy of SiC forms a three-center bond with two silicon neighbors in the vacancy, and gives rise to a new electrically active state. In this paper we examine hydrogen in the anion vacancies of BN, AlN, and GaN. We find that three-center bonding of H is quite common and follows clear trends in terms of the second-neighbor distance in the lattice, the typical (two-center) hydrogen-host-atom bond length, the electronegativity difference between host atoms and hydrogen, as well as the charge state of the vacancy. Three-center bonding limits the number of H atoms a nitrogen vacancy can capture to two, and prevents electric passivation in GaAs as well

Coulomb excitation of 73Ga

The B(E2; Ii -> If) values for transitions in 71Ga and 73Ga were deduced from a Coulomb excitation experiment at the safe energy of 2.95 MeV/nucleon using post-accelerated beams of 71,73Ga at the REX-ISOLDE on-line isotope mass separator facility. The emitted gamma rays were detected by the MINIBALL-detector array and B(E2; Ii->If) values were obtained from the yields normalized to the known strength of the 2+ -> 0+ transition in the 120Sn target. The comparison of these new results with the data of less neutron-rich gallium isotopes shows a shift of the E2 collectivity towards lower excitation energy when adding neutrons beyond N = 40. This supports conclusions from previous studies of the gallium isotopes which indicated a structural change in this isotopical chain between N = 40 and N = 42. Combined with recent measurements from collinear laser spectroscopy showing a 1/2- spin and parity for the ground state, the extracted results revealed evidence for a 1/2-; 3/2- doublet near the ground state in 73 31Ga42 differing by at most 0.8 keV in energy

Early onset of ground-state deformation in the neutron-deficient polonium isotopes

In-source resonant ionization laser spectroscopy of the even-$A$ polonium isotopes $^{192-210,216,218}$Po has been performed using the $6p^37s$ $^5S_2$ to $6p^37p$ $^5P_2$ ($\lambda=843.38$ nm) transition in the polonium atom (Po-I) at the CERN ISOLDE facility. The comparison of the measured isotope shifts in $^{200-210}$Po with a previous data set allows to test for the first time recent large-scale atomic calculations that are essential to extract the changes in the mean-square charge radius of the atomic nucleus. When going to lighter masses, a surprisingly large and early departure from sphericity is observed, which is only partly reproduced by Beyond Mean Field calculations.Comment: As submitted to PR

Coulomb excitation of 68^{68}Ni at safe energies

The $B(E2;0^+\to2^+)$ value in $^{68}$Ni has been measured using Coulomb excitation at safe energies. The $^{68}$Ni radioactive beam was post-accelerated at the ISOLDE facility (CERN) to 2.9 MeV/u. The emitted $\gamma$ rays were detected by the MINIBALL detector array. A kinematic particle reconstruction was performed in order to increase the measured c.m. angular range of the excitation cross section. The obtained value of 2.8$^{+1.2}_{-1.0}$ 10$^2$ e$^2$fm$^4$ is in good agreement with the value measured at intermediate energy Coulomb excitation, confirming the low $0^+\to2^+$ transition probability.Comment: 4 pages, 5 figure

Detailed α-decay study of 180Tl

International audienceA detailed $\alpha$-decay spectroscopy study of $^{180}\mathrm{Tl}$ has been performed at ISOLDE (CERN). $Z$-selective ionization by the Resonance Ionization Laser Ion Source (RILIS) coupled to mass separation provided a high-purity beam of $^{180}\mathrm{Tl}$. Fine-structure $\alpha$ decays to excited levels in the daughter $^{176}\mathrm{Au}$ were identified and an $\alpha$-decay scheme of $^{180}\mathrm{Tl}$ was constructed based on an analysis of $\alpha$-$\gamma$ and $\alpha$-$\gamma$-$\gamma$ coincidences. Multipolarities of several $\gamma$-ray transitions deexciting levels in $^{176}\mathrm{Au}$ were determined. Based on the analysis of reduced $\alpha$-decay widths, it was found that all $\alpha$ decays are hindered, which signifies a change of configuration between the parent and all daughter states

Assessment of nutritional status in children with kidney diseases-clinical practice recommendations from the Pediatric Renal Nutrition Taskforce

In children with kidney diseases, an assessment of the child’s growth and nutritional status is important to guide the dietary prescription. No single metric can comprehensively describe the nutrition status; therefore, a series of indices and tools are required for evaluation. The Pediatric Renal Nutrition Taskforce (PRNT) is an international team of pediatric renal dietitians and pediatric nephrologists who develop clinical practice recommendations (CPRs) for the nutritional management of children with kidney diseases. Herein, we present CPRs for nutritional assessment, including measurement of anthropometric and biochemical parameters and evaluation of dietary intake. The statements have been graded using the American Academy of Pediatrics grading matrix. Statements with a low grade or those that are opinion-based must be carefully considered and adapted to individual patient needs based on the clinical judgment of the treating physician and dietitian. Audit and research recommendations are provided. The CPRs will be periodically audited and updated by the PRNT

First Results on In-Beam gamma Spectroscopy of Neutron-Rich Na and Mg Isotopes at REX-ISOLDE

After the successful commissioning of the radioactive beam experiment at ISOLDE (REX-ISOLDE) - an accelerator for exotic nuclei produced by ISOLDE - first physics experiments using these beams were performed. Initial experiments focused on the region of deformation in the vicinity of the neutron-rich Na and Mg isotopes. Preliminary results show the high potential and physics opportunities offered by the exotic isotope accelerator REX in conjunction with the modern Germanium gamma spectrometer MINIBALL.Comment: 7 pages, RNB6 conference contributio

Does Development Assistance for Health Really Displace Government Health Spending? Reassessing the Evidence

Rajaie Batniji and Eran Bendavid dispute recent suggestions that health aid to developing countries leads to a displacement of government spending and instead argue that current evidence about aid displacement cannot be used to guide policy