2,273 research outputs found
The GALFA-HI Compact Cloud Catalog
We present a catalog of 1964 isolated, compact neutral hydrogen clouds from
the Galactic Arecibo L-Band Feed Array Survey Data Release One (GALFA-HI DR1).
The clouds were identified by a custom machine-vision algorithm utilizing
Difference of Gaussian kernels to search for clouds smaller than 20'. The
clouds have velocities typically between |VLSR| = 20-400 km/s, linewidths of
2.5-35 km/s, and column densities ranging from 1 - 35 x 10^18 cm^-2. The
distances to the clouds in this catalog may cover several orders of magnitude,
so the masses may range from less than a Solar mass for clouds within the
Galactic disc, to greater than 10^4 Solar Masses for HVCs at the tip of the
Magellanic Stream. To search for trends, we separate the catalog into five
populations based on position, velocity, and linewidth: high velocity clouds
(HVCs); galaxy candidates; cold low velocity clouds (LVCs); warm, low
positive-velocity clouds in the third Galactic Quadrant; and the remaining warm
LVCs. The observed HVCs are found to be associated with previously-identified
HVC complexes. We do not observe a large population of isolated clouds at high
velocities as some models predict. We see evidence for distinct histories at
low velocities in detecting populations of clouds corotating with the Galactic
disc and a set of clouds that is not corotating.Comment: 34 Pages, 9 Figures, published in ApJ (2012, ApJ, 758, 44), this
version has the corrected fluxes and corresponding flux histogram and masse
Building a Strategy for Marketing Minnesota's Secondary Materials. Volume II: A Blueprint for Action.
A two-day workshop on developing markets for secondary (recycled) materials was held in December 1989. Thirty-five people came from industry, government, and the academic and nonprofit communities. Some were key decision-makers in industry and state government. The assessments they made about factors inhibiting markets for recycled paper, plastics, glass, and metals are presented here along with the strategies they developed to build up these markets. The results are summarized in a CURA Reporter article in July 1990.Funded in part by a grant from the Northwest Area Foundation
Building a Strategy for Marketing Minnesota's Secondary Materials.
This report was prepared as part of a project designed to explore strategies for marketing secondary materials diverted from the waste streams in Minnesota and other midwestern states. The report provides an introduction to the topic, pulls together existing information on Minnesota's secondary materials and their markets, identified impediments to full market utilization of these materials, outlines options for overcoming these barriers, and reviews state actions in this regard.Funded in part by a grant from the Northwest Area Foundation
Building a Strategy for Marketing Minnesota's Secondary Materials. Volume I: Market Status Report.
Over the twenty years from 1970 to 1990 our nation had almost doubled the amount of solid waste it generates. Recycling part of the waste is increasingly a part of government strategy for coping with the growing volume of garbage. Finding markets for secondary materials such as paper, plastics, glass, and metals has become a major concern. This volume, prepared for a two-day workshop in December 1989, presents background on Minnesota's secondary materials, their markets, what is preventing the full use of these materials, and how such obstacles might be overcome. State actions to encourage markets for these secondary materials are reviewed. While the report focuses on Minnesota, much of it is relevant to the Midwest as a whole. A CURA Reporter article in July 1990 summarizes this study.Funded in part by a grant from the Northwest Area Foundation
Ongoing Galactic Accretion: Simulations and Observations of Condensed Gas in Hot Halos
Ongoing accretion onto galactic disks has been recently theorized to progress
via the unstable cooling of the baryonic halo into condensed clouds. These
clouds have been identified as analogous to the High-Velocity Clouds (HVCs)
observed in HI in our Galaxy. Here we compare the distribution of HVCs observed
around our own Galaxy and extra-planar gas around the Andromeda galaxy to these
possible HVC analogs in a simulation of galaxy formation that naturally
generates these condensed clouds. We find a very good correspondence between
these observations and the simulation, in terms of number, angular size,
velocity distribution, overall flux and flux distribution of the clouds. We
show that condensed cloud accretion only accounts for ~ 0.2 M_solar / year of
the current overall Galactic accretion in the simulations. We also find that
the simulated halo clouds accelerate and become more massive as they fall
toward the disk. The parameter space of the simulated clouds is consistent with
all of the observed HVC complexes that have distance constraints, except the
Magellanic Stream which is known to have a different origin. We also find that
nearly half of these simulated halo clouds would be indistinguishable from
lower-velocity gas and that this effect is strongest further from the disk of
the galaxy, thus indicating a possible missing population of HVCs. These
results indicate that the majority of HVCs are consistent with being infalling,
condensed clouds that are a remnant of Galaxy formation.Comment: 10 pages, 6 figures, ApJ Accepted. Some changes to techniqu
Vaginal bleeding in children: A retrospective audit at a tertiary paediatric gynaecology service
Aim: The aim of this study was to describe the clinical features and investigations of vaginal bleeding in prepubertal children.
Methods: We performed a retrospective case series of children under the age of 10 who presented with vaginal bleeding to our institution between 2018 and 2019.
Results: There were 32 cases identified during the timeframe, with a mean age of 5.5 years (standard deviation 3.2 years, range 5.5 days to 9.6 years). Vulvovaginitis was the most common diagnosis (n = 12, 37.5%), followed by precocious puberty (n = 5, 15.6%). Uncommon but serious causes were vaginal rhabdomyosarcoma (n = 1), and sexual abuse (one patient presenting with gonorrhoea and one with a non-accidental injury). Vaginoscopy was performed in nine patients (28.1%) for various reasons, and a vaginal foreign body was identified in two patients (6.3%). All the patients who had a serious cause of bleeding (neoplasm or sexual assault) or who required specific treatment (precocious puberty, lichen sclerosus, urethral prolapse) presented with red flags on history and/or examination: recurrent episodes of vaginal bleeding, heavy bleeding, associated general symptoms (poor feeding and growth), presence of thelarche, abdominal mass, associated profuse vaginal discharge and abnormal genital examination (skin changes, urethral prolapse or protruding mass from the vagina).
Conclusions: A thorough history-taking and clinical examination aiming at identifying red flags may help to discriminate between benign causes of vaginal bleeding, where no further investigations are indicated, and alternative diagnoses with a poor outcome and/or requiring specific treatment and additional investigations
Head-Tail Clouds: Drops to Probe the Diffuse Galactic Halo
A head-tail high-velocity cloud (HVC) is a neutral hydrogen halo cloud that
appears to be interacting with the diffuse halo medium as evident by its
compressed head trailed by a relatively diffuse tail. This paper presents a
sample of 116 head-tail HVCs across the southern sky (d < 2 deg) from the HI
Parkes All Sky Survey (HIPASS) HVC catalog, which has a spatial resolution of
15.5 arcmin (45 pc at 10 kpc) and a sensitivity of N_HI=2 x 10^(18) cm^(-2) (5
sigma). 35% of the HIPASS compact and semi-compact HVCs (CHVCs and :HVCs) can
be classified as head-tail clouds from their morphology. The clouds have
typical masses of 730 M_sun at 10 kpc (26,000 M_sun at 60 kpc) and the majority
can be associated with larger HVC complexes given their spatial and kinematic
proximity. This proximity, together with their similar properties to CHVCs and
:HVCs without head-tail structure, indicate the head-tail clouds have short
lifetimes, consistent with simulation predictions. Approximately half of the
head-tail clouds can be associated with the Magellanic System, with the
majority in the region of the Leading Arm with position angles pointing in the
general direction of the movement of the Magellanic System. The abundance in
the Leading Arm region is consistent with this feature being closer to the
Galactic disk than the Magellanic Stream and moving through a denser halo
medium. The head-tail clouds will feed the multi-phase halo medium rather than
the Galactic disk directly and provide additional evidence for a diffuse
Galactic halo medium extending to at least the distance of the Magellanic
Clouds.Comment: MNRAS Accepted, 10 figures, 7 in colo
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