Recurrence of Ganglion Cysts Following Re-excision

Previous studies have examined the recurrence of ganglion cysts after surgical excision at a rate of 4 to 40%. However, recurrence after revision surgical excision is unknown. The purpose of this study was to define the incidence of recurrent ganglion cysts in patients who underwent a 2nd excisional procedure.https://jdc.jefferson.edu/cwicposters/1032/thumbnail.jp

The Likelihood Ratio as a tool for Radio Continuum Surveys with SKA precursor telescopes

In this paper we investigate the performance of the likelihood ratio method as a tool for identifying optical and infrared counterparts to proposed radio continuum surveys with SKA precursor and pathfinder telescopes. We present a comparison of the infrared counterparts identified by the likelihood ratio in the VISTA Deep Extragalactic Observations (VIDEO) survey to radio observations with 6, 10 and 15 arcsec resolution. We cross-match a deep radio catalogue consisting of radio sources with peak flux density $>$ 60 $\mu$Jy with deep near-infrared data limited to $K_{\mathrm{s}}\lesssim$ 22.6. Comparing the infrared counterparts from this procedure to those obtained when cross-matching a set of simulated lower resolution radio catalogues indicates that degrading the resolution from 6 arcsec to 10 and 15 arcsec decreases the completeness of the cross-matched catalogue by approximately 3 and 7 percent respectively. When matching against shallower infrared data, comparable to that achieved by the VISTA Hemisphere Survey, the fraction of radio sources with reliably identified counterparts drops from $\sim$89%, at $K_{\mathrm{s}}\lesssim$22.6, to 47% with $K_{\mathrm{s}}\lesssim$20.0. Decreasing the resolution at this shallower infrared limit does not result in any further decrease in the completeness produced by the likelihood ratio matching procedure. However, we note that radio continuum surveys with the MeerKAT and eventually the SKA, will require long baselines in order to ensure that the resulting maps are not limited by instrumental confusion noise.Comment: 10 pages, 7 figures, accepted for publication in mnra

The SKA's the limit : on the nature of faint radio sources

From abstract: Within the next few years a large number of new and vastly more sensitive radio astronomy facilities are scheduled to come online. These new facilities will map large areas of the sky to unprecedented depths and transform radio astronomy into the leading technique for investigating the complex processes which govern the formation and evolution of galaxies. This thesis combines multi-wavelength techniques, highly relevant to future deep radio surveys, to study the evolution and properties of faint radio sources.TeXAdobe Acrobat 9.54 Paper Capture Plug-i

A VLBI study of OH masers in a proto-planetary nebula OH 0.9+1.3

This thesis reports the calibration, imaging and analysis of one epoch of VLBA observations of the 1612 MHz OH maser emission from the protoplanetary nebula OH 0.9+1.3. These are the first polarisation VLBI observations of this source and the spatial morphology of the OH emission is resolved on this scale. Proto-planetary nebulae represent the transition phase in the evolution of stars between the asymptotic giant branch (AGB) phase and their emergence as planetary nebulae. A long-standing astronomical question is how the predominantly spherical circumstellar envelopes of AGB stars evolve into the bipolar and axisymmetric structures that are commonly observed in planetary nebula. Proto-planetary nebulae offer a unique opportunity to study this transformation process. The high-resolution VLBI maps produced in this thesis were used to investigate the morphology and kinematics of OH 0.9+1.3 with a view to gaining insight into the development of asymmetries in the circumstellar material. The OH maser emission of OH 0.9+1.3 has a double-peaked profile with one peak blue-shifted and the other red-shifted with respect to the stellar velocity. The total intensity maser maps demonstrate a considerable degree of asymmetry with the blue- and red-shifted emission located in spatially distinct regions of the envelope. The blue-shifted emission is distributed preferentially along an axis at a projected position angle of » 135± ( North through East). The morphology of this source is not consistent with the standard symmetric thin-shell model and an attempt to fit the traditional OH/IR kinematic model of a simple expanding shell to the maser components was found to be unsatisfactory. No definitive evidence of a bipolar outflow was observed either. The high degree of asymmetry observed in the source is consistent with its status as a proto-planetary nebula. The source was imaged in all four Stokes parameters and the fractional linear and circular polarisations of the maser components were derived from the Stokes parameter maps. In all except one of the components the total fractional polarisation was found to be low ( < 15%). The mean fractional linear and circular polarisation were calculated to be 5.54% and 7.11% respectively. The absence of an identifiable Zeeman pair in the Stokes V map prohibited the estimation of the magnetic field in the circumstellar envelope of this source

A VLBI study of OH masers in a proto-planetary nebula OH 0.9+1.3

This thesis reports the calibration, imaging and analysis of one epoch of VLBA observations of the 1612 MHz OH maser emission from the protoplanetary nebula OH 0.9+1.3. These are the first polarisation VLBI observations of this source and the spatial morphology of the OH emission is resolved on this scale. Proto-planetary nebulae represent the transition phase in the evolution of stars between the asymptotic giant branch (AGB) phase and their emergence as planetary nebulae. A long-standing astronomical question is how the predominantly spherical circumstellar envelopes of AGB stars evolve into the bipolar and axisymmetric structures that are commonly observed in planetary nebula. Proto-planetary nebulae offer a unique opportunity to study this transformation process. The high-resolution VLBI maps produced in this thesis were used to investigate the morphology and kinematics of OH 0.9+1.3 with a view to gaining insight into the development of asymmetries in the circumstellar material. The OH maser emission of OH 0.9+1.3 has a double-peaked profile with one peak blue-shifted and the other red-shifted with respect to the stellar velocity. The total intensity maser maps demonstrate a considerable degree of asymmetry with the blue- and red-shifted emission located in spatially distinct regions of the envelope. The blue-shifted emission is distributed preferentially along an axis at a projected position angle of » 135± ( North through East). The morphology of this source is not consistent with the standard symmetric thin-shell model and an attempt to fit the traditional OH/IR kinematic model of a simple expanding shell to the maser components was found to be unsatisfactory. No definitive evidence of a bipolar outflow was observed either. The high degree of asymmetry observed in the source is consistent with its status as a proto-planetary nebula. The source was imaged in all four Stokes parameters and the fractional linear and circular polarisations of the maser components were derived from the Stokes parameter maps. In all except one of the components the total fractional polarisation was found to be low ( < 15%). The mean fractional linear and circular polarisation were calculated to be 5.54% and 7.11% respectively. The absence of an identifiable Zeeman pair in the Stokes V map prohibited the estimation of the magnetic field in the circumstellar envelope of this source

Evolution in the bias of faint radio sources to z ~ 2.2

Quantifying how the baryonic matter traces the underlying dark matter distribution is key to both understanding galaxy formation and our ability to constrain the cosmological model. Using the cross-correlation function of radio and near-infrared galaxies, we present a large-scale clustering analysis of radio galaxies to z ~ 2.2. We measure the angular auto-correlation function of Ks90μJy to infer linear bias of radio galaxies in four redshift bins. We find that the bias evolves from b = 0.57 ± 0.06 at z ~ 0.3 to 8.55 ± 3.11 at z ~ 2.2. Furthermore, we separate the radio sources into subsamples to determine how the bias is dependent on the radio luminosity, and find a bias which is significantly higher than predicted by the simulations of Wilman et al., and consistent with the lower luminosity but more abundant FR-I population having a similar bias to the highly luminous but rare FR-IIs. Our results are suggestive of a higher mass, particularly for FR-I sources than assumed in simulations, especially towards higher redshift.Peer reviewe

The consumption of protein-rich foods in older adults: An exploratory focus group study

Objective: Many older adults consume inadequate protein for their needs. This study explored the factors associated with the consumption of high-protein foods in older adults. Methods: Participants over the age of 65 years (n = 28) took part in 1 of 4 focus group discussions on meat, fish, eggs, dairy products, nuts, and pulses. Discussions were audio taped, transcribed, and analyzed using thematic analysis. Results: Numerous and various reasons for the consumption and non-consumption of high-protein foods were reported. Many of these reasons result from reductions in chemosensory, dental and physical abilities, and changes in living situation in the older population, and have impact specifically on high-protein foods because of their often hard, perishable and need-to-be-cooked nature, and high cost. Conclusions and Implications: Further work is required to establish the importance of each of thesereasons in relation to protein intakes, to prioritize those of likely greatest impact for increasing intakes. © 2013 Society for Nutrition Education and Behavior

Impact of Redshift Information on Cosmological Applications with Next-Generation Radio Surveys

In this paper, we explore how the forthcoming generation of large-scale radio continuum surveys, with the inclusion of some degree of redshift information, can constrain cosmological parameters. By cross-matching these radio surveys with shallow optical to near-infrared surveys, we can essentially separate the source distribution into a low- and a high-redshift sample, thus providing a constraint on the evolution of cosmological parameters such as those related to dark energy. We examine two radio surveys, the Evolutionary Map of the Universe (EMU) and the Westerbork Observations of the Deep APERTIF Northern sky (WODAN). A crucial advantage is their combined potential to provide a deep, full-sky survey. The surveys used for the cross-identifications are SkyMapper and SDSS, for the southern and northern skies, respectively. We concentrate on the galaxy clustering angular power spectrum as our benchmark observable, and find that the possibility of including such low redshift information yields major improvements in the determination of cosmological parameters. With this approach, and provided a good knowledge of the galaxy bias evolution, we are able to put strict constraints on the dark energy parameters, i.e. w_0=-0.9+/-0.041 and w_a=-0.24+/-0.13, with type Ia supernovae and CMB priors (with a one-parameter bias in this case); this corresponds to a Figure of Merit (FoM) > 600, which is twice better than what is obtained by using only the cross-identified sources and greater than four time better than the case without any redshift information at all.Comment: 12 pages, 6 figures, 6 tables; accepted for publication in MNRA

Insights into the molecular architecture of a peptide nanotube using FTIR and solid-state NMR spectroscopic measurements on an aligned sample

The self-assembly of proteins and peptides into b-sheet-rich amyloid fibers is a process that has gained notoriety because of its association with human diseases and disorders. Spontaneous self-assembly of peptides into nonfibrillar supramolecular structures can also provide a versatile and convenient mechanism for the bottom-up design of biocompatible materials with functional properties favoring a wide range of practical applications.[1] One subset of these fascinating and potentially useful nanoscale constructions are the peptide nanotubes, elongated cylindrical structures with a hollow center bounded by a thin wall of peptide molecules.[2] A formidable challenge in optimizing and harnessing the properties of nanotube assemblies is to gain atomistic insight into their architecture, and to elucidate precisely how the tubular morphology is constructed from the peptide building blocks. Some of these fine details have been elucidated recently with the use of magic-angle-spinning (MAS) solidstate NMR (SSNMR) spectroscopy.[3] MAS SSNMR measurements of chemical shifts and through-space interatomic distances provide constraints on peptide conformation (e.g., b-strands and turns) and quaternary packing. We describe here a new application of a straightforward SSNMR technique which, when combined with FTIR spectroscopy, reports quantitatively on the orientation of the peptide molecules within the nanotube structure, thereby providing an additional structural constraint not accessible to MAS SSNMR