Emerging beam resonances in atom diffraction from a reflection grating

We report on the observation of emerging beam resonances, well known as Rayleigh-Wood anomalies and threshold resonances in photon and electron diffraction, respectively, in an atom-optical diffraction experiment. Diffraction of He atom beams reflected from a blazed ruled grating at grazing incidence has been investigated. The total reflectivity of the grating as well as the intensities of the diffracted beams reveal anomalies at the Rayleigh angles of incidence, i.e., when another diffracted beam merges parallel to the grating surface. The observed anomalies are discussed in terms of the classical wave-optical model of Rayleigh and Fano.Comment: 4 pages, 3 figure

Effect of alirocumab on lipids and lipoproteins in individuals with metabolic syndrome without diabetes: Pooled data from 10 phase 3 trials.

AimsThis analysis assessed the efficacy and safety of alirocumab, a proprotein convertase subtilisin/kexin type 9 inhibitor, in patients with or without metabolic syndrome (MetS) using pooled data from 10 phase 3 ODYSSEY trials.Materials and methodsData from 4983 randomized patients (1940 with MetS; 1642 with diabetes excluded) were assessed in subgroups by MetS status. Efficacy data were analysed in 4 pools per study design: 2 placebo-controlled pools (1 using alirocumab 150 mg every 2 weeks [Q2W], 1 using 75/150 mg Q2W) with background statin, and 2 ezetimibe-controlled pools (both alirocumab 75/150 mg Q2W), 1 with and 1 without background statin. Alirocumab 75/150 mg indicates possible dose increase from 75 to 150 mg at Week 12 based on Week 8 LDL-C.ResultsLDL-C percentage reduction from baseline at Week 24 with alirocumab was 63.9% (MetS) and 56.8% (non-MetS) in the pool of alirocumab 150 mg Q2W, and 42.2% to 52.2% (MetS) and 45.0% to 52.6% (non-MetS) in 3 pools using 75/150 mg Q2W. Levels of other lipid and lipoprotein parameters were also improved with alirocumab treatment, including apolipoprotein B, non-high-density lipoprotein cholesterol (non-HDL-C), lipoprotein(a) and HDL-C. Overall, the percentage change at Week 24 in LDL-C and other lipids and lipoproteins did not vary by MetS status. Adverse event rates were generally similar between treatment groups, regardless of MetS status; injection-site reactions occurred more frequently in alirocumab vs control groups.ConclusionsAcross study pools, alirocumab-associated reductions in LDL-C, apolipoprotein B, and non-HDL-C were significant vs control, and did not vary by MetS status

Constraints on the symmetry energy and on neutron skins from the pygmy resonances in 68Ni and 132Sn

Correlations between the behavior of the nuclear symmetry energy, the neutron skins, and the percentage of energy-weighted sum rule (EWSR) exhausted by the Pygmy Dipole Resonance (PDR) in 68Ni and 132Sn have been investigated by using different Random Phase Approximation (RPA) models for the dipole response, based on a representative set of Skyrme effective forces plus meson-exchange effective Lagrangians. A comparison with the experimental data has allowed us to constrain the value of the derivative of the symmetry energy at saturation. The neutron skin radius is deduced under this constraint.Comment: Accepted for publication in PRC Rapid Comminicatio

Recommendations for Communication Centers based on Student and Tutor Reflections: Insights about Students’ Reasons for Visiting, Session Outcomes, and Characteristics of the Tutoring Approach

This paper explores students’ experiences with communication centers and offers recommendations for new and expanding communication centers. We combine empirical research conducted on student reflection forms with our own insight as tutors, instructors, and directors and with existing literature to offer considerations for enhancing the services offered by communication centers. We propose communication centers consider the purposes for and outcomes of students’ visits, as well as what attributes of the tutoring and tutors students appreciate. Reasons for visiting the communication center included to receive help with content and structure, delivery, and sources and visual aids. Students reported getting assistance with drafting, delivery, supporting, and debriefing their presentations. The approaches to tutoring students appreciated included guided learning, clarification of course materials, and identification of both their strengths and weaknesses. Tutor characteristics appreciated by students were their prior teaching experience, good listening skills, creativity, and demeanor

Macro- and micro-scale studies on U(VI) immobilization in hardened cement paste

Wet chemistry and synchrotron-based (micro-)spectroscopic investigations have been carried out to determine the uptake and speciation of U(VI) in hardened cement paste (HCP). The wet chemistry experiments included kinetic studies and the determination of the sorption isotherm. The latter measurements allowed conditions for linear sorption to be distinguished from those where precipitation occurred. Micro-X-ray fluorescence and X-ray absorption spectroscopy (μ-XRF/XAS) were used to determine the elemental distribution and the coordination environment of U(VI) in an intact HCP sample at the atomic level. The sample was prepared by in-diffusion of U(VI) into HCP over 9months. Micro-XRF maps revealed a heterogeneous distribution of U(VI) in a ten micron thick layer on the surface of the HCP disk. Micro-XAS measurements on a U(VI) hot spot showed that the coordination environment of U(VI) is similar to that in U(VI) doped HCP and in C-S-H sorption samples. To the best of our knowledge this is the first synchrotron-based micro-spectroscopic study on the speciation of diffusing uranyl ions with micro-scale spatial resolutio

Surface characterization

The biocompatibility of commercially pure titanium and its alloys is closely related to their surface properties, with both the composition of the protecting oxide film and the surface topography playing an important role. Surfaces of commercially pure titanium and of the two alloys Ti-6Al-7Nb and Ti-6Al-4V (wt %) have been investigated following three different pretreatments: polishing, nitric acid passivation and pickling in nitric acid-hydrogen fluoride. Nitric acid treatment is found to substantially reduce the concentration of surface contaminants present after polishing. The natural 4-6 nm thick oxide layer on commercially pure titanium is composed of titanium oxide in different oxidation states (TiO2, Ti2O3 and TiO), while for the alloys, aluminium and niobium or vanadium are additionally present in oxidized form (Al2O3, Nb2O5 or V-oxides). The concentrations of the alloying elements at the surface are shown to be strongly dependent on the pretreatment process. While pickling increases the surface roughness of both commercially pure titanium and the alloys, different mechanisms appear to be involved. In the case of commercially pure titanium, the dissolution rate depends on grain orientation, whereas in the case of the two alloys, selective α-phase dissolution and enrichment of the β-phase appears to occur. © 1999 Kluwer Academic Publisher

Rational Moral Ignorance

Philosophy and Phenomenological Research, EarlyView

Measurement of the reaction \gamma p \TO K^ + \Lambda(1520) at photon energies up to 2.65 GeV

The reaction \gamma p \TO K^+\Lambda(1520) was measured in the energy range from threshold to 2.65 GeV with the SAPHIR detector at the electron stretcher facility ELSA in Bonn. The $\Lambda(1520)$ production cross section was analyzed in the decay modes $pK^-$, $n \bar{K}^0$, $\Sigma^{\pm}\pi^{\mp}$, and $\Lambda\pi^+\pi^-$ as a function of the photon energy and the squared four-momentum transfer $t$. While the cross sections for the inclusive reactions rise steadily with energy, the cross section of the process \gamma p \TO K^+\Lambda(1520) peaks at a photon energy of about 2.0 GeV, falls off exponentially with $t$, and shows a slope flattening with increasing photon energy. The angular distributions in the $t$-channel helicity system indicate neither a $K$ nor a $K^\star$ exchange dominance. The interpretation of the $\Lambda(1520)$ as a $\Sigma(1385)\pi$ molecule is not supported.Comment: 11 pages, 16 figures, 4 table