727 research outputs found
Evaluating the Relationship Between Transportation Infrastructure and Economic Activity: Evidence from Washington State
Detection and characterization of Io's atmosphere from high-resolution 4-{\mu}m spectroscopy
We report on high-resolution and spatially-resolved spectra of Io in the 4.0
{\mu}m region, recorded with the VLT/CRIRES instrument in 2008 and 2010, which
provide the first detection of the {\nu}1 + {\nu}3 band of SO2 in Io's
atmosphere. Data are analyzed to constrain the latitudinal, longitudinal, and
diurnal distribution of Io's SO2 atmosphere as well as its characteristic
temperature. equatorial SO2 column densities clearly show longitudinal
asymmetry, but with a maximum of around 1.5e17 cm-2 at central meridian
longitude L = 200-220 and a minimum of around 3e16 cm-2 at L = 285-300, the
longitudinal pattern somewhat differs from earlier inferences from Ly {\alpha}
and thermal IR measurements. Within the accuracy of the measurements, no
evolution of the atmospheric density from mid-2008 to mid-2010 can be
distinguished. The decrease of the SO2 column density towards high latitude is
apparent, and the typical latitudinal extent of the atmosphere found to be (+-)
40{\deg} at half-maximum. The data show moderate diurnal variations of the
equatorial atmosphere, which is evidence for a partially sublimation-supported
atmospheric component. Compared to local noon, factor of 2 lower densities are
observed around 40{\deg} before and 80{\deg} after noon. Best-fit gas
temperatures range from 150 to 220 K, with a weighted mean value of 170 (+-) 20
K, which should represent the column-weighted mean kinetic temperature of Io's
atmosphere. Finally, although the data include clear thermal emission due to
Pillan (in outburst in July 2008) and Loki, no detectable enhancements in the
SO2 atmosphere above these volcanic regions are found, with an upper limit of
4e16 cm-2 at Pillan and 1e17 cm-2 at Loki.Comment: Accepted for publication in Icaru
Identification of Brush Species and Herbicide Effect Assessment in Southern Texas Using an Unoccupied Aerial System (UAS)
Cultivation and grazing since the mid-nineteenth century in Texas has caused dramatic changes in grassland vegetation. Among these changes is the encroachment of native and introduced brush species. The distribution and quantity of brush can affect livestock production and water holding capacity of soil. Still, at the same time, brush can improve carbon sequestration and enhance agritourism and real estate value. The accurate identification of brush species and their distribution over large land tracts are important in developing brush management plans which may include herbicide application decisions. Near-real-time imaging and analyses of brush using an Unoccupied Aerial System (UAS) is a powerful tool to achieve such tasks. The use of multispectral imagery collected by a UAS to estimate the efficacy of herbicide treatment on noxious brush has not been evaluated previously. There has been no previous comparison of band combinations and pixel- and object-based methods to determine the best methodology for discrimination and classification of noxious brush species with Random Forest (RF) classification. In this study, two rangelands in southern Texas with encroachment of huisache (Vachellia farnesianna [L.] Wight & Arn.) and honey mesquite (Prosopis glandulosa Torr. var. glandulosa) were studied. Two study sites were flown with an eBee X fixed-wing to collect UAS images with four bands (Green, Red, Red-Edge, and Near-infrared) and ground truth data points pre- and post-herbicide application to study the herbicide effect on brush. Post-herbicide data were collected one year after herbicide application. Pixel-based and object-based RF classifications were used to identify brush in orthomosaic images generated from UAS images. The classification had an overall accuracy in the range 83â96%, and object-based classification had better results than pixel-based classification since object-based classification had the highest overall accuracy in both sites at 96%. The UAS image was useful for assessing herbicide efficacy by calculating canopy change after herbicide treatment. Different effects of herbicides and application rates on brush defoliation were measured by comparing canopy change in herbicide treatment zones. UAS-derived multispectral imagery can be used to identify brush species in rangelands and aid in objectively assessing the herbicide effect on brush encroachment
Plus One: Managing the relationship
Plus One: HIV sero-discordant relationships among black African people in England (NAHIP)
Duration: September 2010 - November 2011
Plus One involved in-depth, face-to-face interviews with black African people living in England who were in relationships where one person had diagnosed HIV and the other did not (ie. HIV serodiscordant)
Plus One: External Influences
Plus One: HIV sero-discordant relationships among black African people in England (NAHIP)
Duration: September 2010 - November 2011
Plus One involved in-depth, face-to-face interviews with black African people living in England who were in relationships where one person had diagnosed HIV and the other did not (ie. HIV serodiscordant).
Catherine Dodds, Peter , Annabel ,
Edith , John , Lawrence , Pamela , Kathie & Gary
Plus One: Sex and risk
Plus One: HIV sero-discordant relationships among black African people in England (NAHIP)
Duration: September 2010 - November 2011
Plus One involved in-depth, face-to-face interviews with black African people living in England who were in relationships where one person had diagnosed HIV and the other did not (ie. HIV serodiscordant)
Plus One: Executive Summary
Plus One: HIV sero-discordant relationships among black African people in England (NAHIP)
Duration: September 2010 - November 2011
Plus One involved in-depth, face-to-face interviews with black African people living in England who were in relationships where one person had diagnosed HIV and the other did not (ie. HIV serodiscordant)
Models of the SL9 Impacts II. Radiative-hydrodynamic Modeling of the Plume Splashback
We model the plume "splashback" phase of the SL9 collisions with Jupiter
using the ZEUS-3D hydrodynamic code. We modified the Zeus code to include gray
radiative transport, and we present validation tests. We couple the infalling
mass and momentum fluxes of SL9 plume material (from paper I) to a jovian
atmospheric model. A strong and complex shock structure results. The modeled
shock temperatures agree well with observations, and the structure and
evolution of the modeled shocks account for the appearance of high excitation
molecular line emission after the peak of the continuum light curve. The
splashback region cools by radial expansion as well as by radiation. The
morphology of our synthetic continuum light curves agree with observations over
a broad wavelength range (0.9 to 12 microns). A feature of our ballistic plume
is a shell of mass at the highest velocities, which we term the "vanguard".
Portions of the vanguard ejected on shallow trajectories produce a lateral
shock front, whose initial expansion accounts for the "third precursors" seen
in the 2-micron light curves of the larger impacts, and for hot methane
emission at early times. Continued propagation of this lateral shock
approximately reproduces the radii, propagation speed, and centroid positions
of the large rings observed at 3-4 microns by McGregor et al. The portion of
the vanguard ejected closer to the vertical falls back with high z-component
velocities just after maximum light, producing CO emission and the "flare" seen
at 0.9 microns. The model also produces secondary maxima ("bounces") whose
amplitudes and periods are in agreement with observations.Comment: 13 pages, 9 figures (figs 3 and 4 in color), accepted for Ap.J.
latex, version including full figures at:
http://oobleck.tn.cornell.edu/jh/ast/papers/slplume2-20.ps.g
Impact of Scottish vocational qualifications on residential child care : have they fulfilled the promise?
This article will present findings from a doctoral study exploring the impact of 'SVQ Care: Promoting Independence (level III)' within children's homes. The study focuses on the extent to which SVQs enhance practice and their function within a 'learning society'. A total of 30 staff were selected from seven children's homes in two different local authority social work departments in Scotland. Each member of staff was interviewed on four separate occasions over a period of 9 months. Interviews were structured using a combination of repertory grids and questions. Particular focus was given to the assessment process, the extent to which SVQs enhance practice and the learning experiences of staff. The findings suggest that there are considerable deficiencies both in terms of the SVQ format and the way in which children's homes are structured for the assessment of competence. Rather than address the history of failure within residential care, it appears that SVQs have enabled the status quo to be maintained whilst creating an 'illusion' of change within a learning society
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