Non-Gaussianities in Multifield Inflation: Superhorizon Evolution, Adiabaticity, and the Fate of fnl

We explore the superhorizon generation of large fnl of the local form in two field inflation. We calculate the two- and three-point observables in a general class of potentials which allow for an analytic treatment using the delta N formalism. Motivated by the conservation of the curvature perturbation outside the horizon in the adiabatic mode and also by the observed adiabaticity of the power spectrum, we follow the evolution of fnl^{local} until it is driven into the adibatic solution by passing through a phase of effectively single field inflation. We find that although large fnl^{local} may be generated during inflation, such non-gaussianities are transitory and will be exponentially damped as the cosmological fluctuations approach adiabaticity.Comment: v3: Typos corrected, minor changes to match published version, references added, 18 pages, 1 figure. v2: Changed sign of fnl to match WMAP convention, minor changes throughout, references added, 18 pages, 1 figure. v1: 17 pages, 1 figur

New cluster members and halo stars of the Galactic globular cluster NGC 1851

NGC 1851 is an intriguing Galactic globular cluster, with multiple stellar evolutionary sequences, light and heavy element abundance variations and indications of a surrounding stellar halo. We present the first results of a spectroscopic study of red giant stars within and outside of the tidal radius of this cluster. Our results identify nine probable new cluster members (inside the tidal radius) with heliocentric radial velocities consistent with that of NGC 1851. We also identify, based on their radial velocities, four probable extratidal cluster halo stars at distances up to ~3.1 times the tidal radius, which are supportive of previous findings that NGC 1851 is surrounded by an extended stellar halo. Proper motions were available for 12 of these 13 stars and all are consistent with that of NGC 1851. Apart from the cluster members and cluster halo stars, our observed radial velocity distribution agrees with the expected distribution from a Besancon disk/N-body stellar halo Milky Way model generated by the Galaxia code, suggesting that no other structures at different radial velocities are present in our field. The metallicities of these stars are estimated using equivalent width measurements of the near infrared calcium triplet absorption lines and are found, within the limitations of this method, to be consistent with that of NGC 1851. In addition we recover 110 red giant cluster members from previous studies based on their radial velocities and identify three stars with unusually high radial velocities.Comment: 10 pages, 8 figures. Accepted for publication in MNRA

New halo stars of the Galactic globular clusters M3 and M13 in the LAMOST DR1 Catalog

M3 and M13 are Galactic globular clusters with previous reports of surrounding stellar halos. We present the results of a search for members and extratidal cluster halo stars within and outside of the tidal radius of these clusters in the LAMOST Data Release 1. We find seven candidate cluster members (inside the tidal radius) of both M3 and M13 respectively. In M3 we also identify eight candidate extratidal cluster halo stars at distances up to ~9.8 times the tidal radius, and in M13 we identify 12 candidate extratidal cluster halo stars at distances up to ~13.8 times the tidal radius. These results support previous indications that both M3 and M13 are surrounded by extended stellar halos, and we find that the GC destruction rates corresponding to the observed mass loss are generally significantly higher than theoretical studies predict.Comment: 21 pages, 10 figures. Accepted for publication in Ap

Analysis and evaluation of current materials at the intermediate grade level for the correction of word attack deficiencies

Reading teachers are often lacking in time and facilities for getting a comprehensive overview of important skills and materials taught at the intermediate grade level for guiding children in their efforts to acquire independence in word attack. The problem of this study was to analyze, evaluate, and compile current materials consisting of workbooks, reading games, and audio-visual aids to ascertain which skills are presented to correct word attack deficiencies

Seeking consensus regarding the characteristics of expertise and development requirements across five domains of netball coaching in the United Kingdom

The aim of this study was to develop consensus of opinion from expert netball coaches by exploring prime defining characteristics of, and prime development requirements for, coaching expertise. Forty-eight expert female netball coaches representing five domains were recruited. A four-round Delphi Poll technique was utilised to generate consensus of prime characteristics of expertise and prime development requirements. Distinct characteristics of expertise were identified in each domain. The domain-specific characteristics of expertise dispute the appropriateness of a one-size-fits-all coach development approach such as coaching courses which are not bespoke. Concerning development requirements, the findings demonstrated support for individualised, predominantly informal approaches

Quantitative analysis of pedestrian counterflow in a cellular automaton model

Pedestrian dynamics exhibits various collective phenomena. Here we study bidirectional pedestrian flow in a floor field cellular automaton model. Under certain conditions, lane formation is observed. Although it has often been studied qualitatively, e.g., as a test for the realism of a model, there are almost no quantitative results, neither empirically nor theoretically. As basis for a quantitative analysis we introduce an order parameter which is adopted from the analysis of colloidal suspensions. This allows to determine a phase diagram for the system where four different states (free flow, disorder, lanes, gridlock) can be distinguished. Although the number of lanes formed is fluctuating, lanes are characterized by a typical density. It is found that the basic floor field model overestimates the tendency towards a gridlock compared to experimental bounds. Therefore an anticipation mechanism is introduced which reduces the jamming probability.Comment: 11 pages, 12 figures, accepted for publication in Phys. Rev.

ESO452-SC11: The lowest mass globular cluster with a potential chemical inhomogeneity

We present the largest spectroscopic investigation of one of the faintest and least studied stellar clusters of the Milky Way, ESO452-SC11. Using the Anglo-Australian Telescope AAOmega and Keck HIRES spectrographs we have identified 11 members of the cluster and found indications of star-to-star light element abundance variation, primarily using the blue cyanogen (CN) absorption features. From a stellar density profile, we estimate a total cluster mass of $(6.8\pm3.4)\times10^3$ solar masses. This would make ESO452-SC11 the lowest mass cluster with evidence for multiple populations. These data were also used to measure the radial velocity of the cluster ($16.7\pm0.3$ km s$^{-1}$) and confirm that ESO452-SC11 is relatively metal-rich for a globular cluster ([Fe/H]$=-0.81\pm0.13$). All known massive clusters studied in detail show multiple populations of stars each with a different chemical composition, but many low-mass globular clusters appear to be chemically homogeneous. ESO452-SC11 sets a lower mass limit for the multiple stellar population phenomenon.Comment: 13 pages, 11 figures. Accepted for publication in MNRA

Evaporation of alpha particles from 31^31P nucleus

The energy spectra of alpha particles have been measured in coincidence with the evaporation residues for the decay of the compound nucleus $^31$P produced in the reaction $^19$F (96 MeV) + $^12$C. The data have been compared with the predictions of the statistical model code CASCADE. It has been observed that significant deformation effect in the compound nucleus need to be considered in order to explain the shape of the evaporated alpha particle energy spectra.Comment: 4 pages, 3 figures, revtex, epsf styl