Vibrational Feshbach Resonances Mediated by Nondipole Positron-Molecule Interactions

Measurements of energy-resolved positron-molecule annihilation show the existence of positron binding and vibrational Feshbach resonances. The existing theory describes this phenomenon successfully for the case of infrared-active vibrational modes which allow dipole coupling between the incident positron and the vibrational motion. Presented here are measurements of positron-molecule annihilation made using a recently developed cryogenic positron beam capable of significantly improved energy resolution. The results provide evidence of resonances associated with infrared-inactive vibrational modes, indicating that positron-molecule bound states may be populated by nondipole interactions. The anticipated ingredients for a theoretical description of such interactions are discussed.Comment: 5 pages, 2 figures, Phys. Rev. Lett. (in press

Coherent resonant interactions and slow light with molecules confined in photonic band-gap fibers

We investigate resonant nonlinear optical interactions and demonstrate induced transparency in acetylene molecules in a hollow-core photonic band-gap fiber at 1.5$\mu$m. The induced spectral transmission window is used to demonstrate slow-light effects, and we show that the observed broadening of the spectral features is due to collisions of the molecules with the inner walls of the fiber core. Our results illustrate that such fibers can be used to facilitate strong coherent light-matter interactions even when the optical response of the individual molecules is weak.Comment: 5 pages, 4 figure

Exploration of the faecal microbiota and biomarker discovery in equine grass sickness

Equine grass sickness (EGS) is a frequently fatal disease of horses, responsible for the death of 1-2% of the UK horse population annually. The etiology of this disease is currently uncharacterized although there is evidence it is associated with Clostridium botulinum neurotoxin in the gut. Prevention is currently not possible and ileal biopsy diagnosis is invasive. The aim of this study was to characterize the fecal microbiota and biofluid metabolic profiles of EGS horses, to further understand the mechanisms underlying this disease and identify metabolic biomarkers to aid in diagnosis. Urine, plasma and feces were collected from horses with EGS, matched controls (MC), and hospital controls (HC). Sequencing the16S rRNA gene of the fecal bacterial population of the study horses found a severe dysbiosis in EGS horses, with an increase in Bacteroidetes and a decrease in Firmicutes bacteria. Metabolic profiling by 1H nuclear magnetic resonance (NMR) spectroscopy found EGS to be associated with the lower urinary excretion of hippurate and 4-cresyl sulfate and higher excretion of O-acetyl carnitine and trimethylamine-N-oxide (TMAO). The predictive ability of the complete urinary metabolic signature and using the four discriminatory urinary metabolites to classify horses by disease status was assessed using a second (test) set of horses. The urinary metabolome and a combination of the four candidate biomarkers showed promise in aiding the identification of horses with EGS. Characterization of the metabolic shifts associated with EGS offers the potential of a non-invasive test to aid pre-mortem diagnosis

Closed forms and multi-moment maps

We extend the notion of multi-moment map to geometries defined by closed forms of arbitrary degree. We give fundamental existence and uniqueness results and discuss a number of essential examples, including geometries related to special holonomy. For forms of degree four, multi-moment maps are guaranteed to exist and are unique when the symmetry group is (3,4)-trivial, meaning that the group is connected and the third and fourth Lie algebra Betti numbers vanish. We give a structural description of some classes of (3,4)-trivial algebras and provide a number of examples.Comment: 36 page

Nonlinear Dirac operator and quaternionic analysis

Properties of the Cauchy-Riemann-Fueter equation for maps between quaternionic manifolds are studied. Spaces of solutions in case of maps from a K3-surface to the cotangent bundle of a complex projective space are computed. A relationship between harmonic spinors of a generalized nonlinear Dirac operator and solutions of the Cauchy-Riemann-Fueter equation are established.Comment: Cosmetic changes onl

Bad bosses and self-verification: the moderating role of core self-evaluations with trust in workplace management

Who responds most strongly to supervisor social undermining? Building on self-verification theory (Swann, 1983, 1987), we theorize that employees with positive views of the self (i.e., higher core self-evaluations [CSEs]) who also maintain higher trust in workplace management are more likely to experience heightened stress and turnover intentions when undermined. We argue that this subset of employees (high CSE, high trust) are more likely to feel misunderstood when undermined by their supervisor and that this lack of self-verification partially explains their stronger responses to supervisor undermining. We find initial support for the first part of our model in a study of 259 healthcare workers in the United States and replicate and extend our findings in the second study of 330 employees in the United Kingdom. Our results suggest that the employees Human Resources often wishes to attract and retain—employees with high CSE and high trust in workplace management—react most strongly to supervisor social undermining