6,168 research outputs found
Perineal Abscess Secondary to Gas Gangrene - Use of Hyperbaric Oxygen as a Therapeutic Adjunct in a Case
Hyperbaric oxygen treatment of perineal abcess in human male with acute urinary tract difficult
Central galaxy growth and feedback in the most massive nearby cool core cluster
We present multi-wavelength observations of the centre of RXCJ1504.1-0248 -
the galaxy cluster with the most luminous and relatively nearby cool core at
z~0.2. Although there are several galaxies within 100 kpc of the cluster core,
only the brightest cluster galaxy (BCG), which lies at the peak of the X-ray
emission, has blue colours and strong line-emission. Approximately 80 Msun/yr
of intracluster gas is cooling below X-ray emitting temperatures, similar to
the observed UV star formation rate of ~140 Msun/yr. Most star formation occurs
in the core of the BCG and in a 42 kpc long filament of blue continuum, line
emission, and X-ray emission, that extends southwest of the galaxy. The
surrounding filamentary nebula is the most luminous around any observed BCG.
The number of ionizing stars in the BCG is barely sufficient to ionize and heat
the nebula, and the line ratios indicate an additional heat source is needed.
This heat source can contribute to the H\alpha-deduced star formation rates
(SFRs) in BCGs and therefore the derived SFRs should only be considered upper
limits. AGN feedback can slow down the cooling flow to the observed mass
deposition rate if the black hole accretion rate is of the order of 0.5 Msun/yr
at 10% energy output efficiency. The average turbulent velocity of the nebula
is vturb ~325 km/s which, if shared by the hot gas, limits the ratio of
turbulent to thermal energy of the intracluster medium to less than 6%.Comment: 15 pages, 11 figures, MNRAS in press. Corrected typo in abstract
Interlot, intralot, and time variations in pH of commercially available artificial tears
This study examines the stability and range of pH in several commercially available artificial tear preparations. pH immediately upon opening varies between 6.4 and 8.5 among the preparations. pH fluctuation was not found to occur in five of the seven preparations. The pH of one lot of a multiple use artificial tear decreased 0.4 units during the first week and then remained stable for the following 21 days. pH was found to vary by 0.5 units between lots in one brand of a single use artificial tear preparation. These results allow for informed selection of artificial tears in the treatment of dry eye
Workshop I: Research Training Wrap-up
This presentation completes Workshop I with final assignments and details about Workshop II scheduled for February 2019
The extended H-alpha emitting filaments surrounding NGC4696, the central galaxy of the Centaurus cluster
We present images of NGC4696, the central galaxy in the Centaurus cluster,
showing the large extent of cool filaments which are bright in H-alpha line
emission. These filaments share the detailed structure of both the central dust
lane and the inner regions of the arc-like plumes seen in soft X-ray emission.
The X-ray gas is at its coolest, and most absorbed in this same region. The
smoothness of the features implies that the local environment is not strongly
turbulent. We suggest that these filaments are either shaped by confinement due
to a strong magnetic field, or by bulk flows within the intracluster medium. We
propose that like similar filamentary systems in the core of clusters, these
cooler components have been drawn out of the central galaxy behind buoyant gas
bubbles from previous episodes of radio activity. We find a spur of
low-frequency radio emission leading to a region of low X-ray pressure within
the intracluster medium supporting this interpretation.Comment: 7 pages, including 5 composite figures; accepted for publication in
MNRAS. Copy of paper with best quality figures available at
http://www-xray.ast.cam.ac.uk/~csc/centaurus.htm
Hydrogen Two-Photon Continuum Emission from the Horseshoe Filament in NGC 1275
Far ultraviolet emission has been detected from a knot of Halpha emission in
the Horseshoe filament, far out in the NGC 1275 nebula. The flux detected
relative to the brightness of the Halpha line in the same spatial region is
very close to that expected from Hydrogen two-photon continuum emission in the
particle heating model of Ferland et al. (2009) if reddening internal to the
filaments is taken into account. We find no need to invoke other sources of far
ultraviolet emission such as hot stars or emission lines from CIV in
intermediate temperature gas to explain these data.Comment: 9 pages, 8 figures. Accepted for publication in MNRA
Heterogeneous uptake of the C1 to C4 organic acids on a swelling clay mineral
Mineral aerosol is of interest due to its physiochemical impacts on the Earth's atmosphere. However, adsorbed organics could influence the chemical and physical properties of atmospheric mineral particles and alter their impact on the biosphere and climate. In this work, the heterogeneous uptake of a series of small organic acids on the swelling clay, Na-montmorillonite, was studied at 212 K as a function of relative humidity (RH), organic acid pressure and clay mass. A high vacuum chamber equipped with a quadrupole mass spectrometer and a transmission Fourier transform infrared spectrometer was used to detect the gas and condensed phases, respectively. Our results show that while the initial uptake efficiency was found to be independent of organic acid pressure, it increased linearly with increasing clay mass. Thus, the small masses studied allow access to the entire surface area of the clay sample with minimal effects due to surface saturation. Additionally, results from this study show that the initial uptake efficiency for butanoic (butyric) acid on the clay increases by an order of magnitude as the RH is raised from 0% to 45% RH at 212 K while the initial uptake efficiency of formic, acetic and propanoic (propionic) acids increases only slightly at higher humidities. However, the initial uptake efficiency decreases significantly in a short amount of time due to surface saturation effects. Thus, although the initial uptake efficiencies are appropriate for initial times, the fact that the uptake efficiency will decrease over time as the surface saturates should be considered in atmospheric models. Surface saturation results in sub-monolayer coverage of organic acid on montmorillonite under dry conditions and relevant organic acid pressures that increases with increasing humidity for all organic acids studied. Additionally, the presence of large organic acids may slightly enhance the water content of the clay above 45% RH. Our results indicate that heterogeneous uptake of organic acids on swelling clay minerals provides an important irreversible heterogeneous sink for these species
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