14,588 research outputs found
Land use and environmental assessment in the central Atlantic region
Data from high altitude aircraft, LANDSAT and Skylab were used in a comprehensive regional survey of land use and its associated environmental impact in the Central Atlantic Regional Ecological Test Site (CARETS). Each sensor system has advantages that were demonstrated by producing experimental land use maps and other data products, applying them to typical problems encountered in regional planning and environmental impact assessment, and presenting the results to prospective users for evaluation. An archival collection of imagery, maps, data summaries, and technical reports was assembled, constituting an environmental profile of the central Atlantic region. The investigation was organized into four closely-related modules, a land use information module, an environmental impact module, a user interaction and evaluation module, and a geographic information systems module. Results revealed a heterogeneous user community with diverse information needs, tending, however, definitely toward the higher-resolution sensor data and the larger-scale land use maps and related information products. Among project recommendations are greater efforts toward improving compatibility of federal, state, and local land use information programs, and greater efforts toward a broader exchange of imagery, computer tapes, and land use information derived therefrom
A Reanalysis of the Carbon Abundance in the Translucent Cloud toward HD 24534
We have reanalyzed the Goddard High Resolution Spectrograph data set
presented by Snow et al. which contains the interstellar intersystem C II]
2325A line through the translucent cloud toward HD 24534 (X Persei). In
contrast to the results of Snow et al., we clearly detect the C II] feature at
the 3-sigma confidence level and measure a C^+ column density of 2.7 +/- 0.8 x
10^17 cm^-2. Accounting for the C I column density along the line of sight, we
find 10^6 C/H = 106 +/- 38 in the interstellar gas toward this star. This
gas-phase carbon-to-hydrogen ratio suggests that slightly more carbon depletion
may be occurring in translucent as compared to diffuse clouds. The average
diffuse-cloud C/H, however, is within the 1-sigma uncertainty of the
measurement toward HD 24534. We therefore cannot rule out the possibility that
the two cloud types have comparable gas-phase C/H, and therefore comparable
depletions of carbon.Comment: 9 pages, 3 figures, to appear in the Astrophysical Journal Letter
CARETS: A prototype regional environmental information system. Volume 2, parts A and B: Norfolk and environs; a land use perspective
The author has identified the following significant results. The Norfolk-Portsmouth metropolitan statistical area in southeastern Virginia was the site of intensive testing of a number of land resources assessment methods. Land use and land cover data at three levels of detail were derived by manual image interpretation from both aircraft and satellite sources and used to characterize the 1,766 sq km (682 sq mi) area from the perspective of its various resource-related activities and problems. Measurements at level 1 from 1:100, 000 scale maps revealed 42 percent of the test area (excluding bays and estuaries) to be forest, 28 percent agriculture, 23 percent urban and built-up, 4 percent nonforested wetlands, and 2 percent water. At the same scale and level of detail, 10 percent of the area underwent change from one land use category to another in the period 1959-70, 62 percent of which involved the relatively irreversible change from forest or agriculture to urban uses
The effect of material cyclic deformation properties on residual stress generation by laser shock processing
Laser shock processing (LSP) is a mechanical surface treatment to induce a compressive residual stress state into the near surface region of a metallic component. The effect of the cyclic deformation properties of ductile materials on the final residual stress fields obtained by LSP is analysed. Conventional modelling approaches either use simple tensile yield criteria, or isotropic hardening models if cyclic straining response is considered for the material during the peen processing. In LSP, the material is likely to be subject to cyclic loading because of reverse yielding after the initial plastic deformation. The combination of experiment and modelling shows that the incorporation of experimentally-determined cyclic stress-strain data, including mechanical hysteresis, into material deformation models is required to correctly reflect the cyclic deformation processes during LSP treatment and obtain accurate predictions of the induced residual stresses.</p
Co-creating an Adventure Playground (CAP): Reading playwork stories, practices and artefacts, Gloucester: University of Gloucestershire
This report draws on findings from an action research project carried out with an adventure playground (AP) over a six-month period during summer/autumn 2013. The overall intention was to explore the ways in which playwork practitioners at the playground make sense of and give meaning to their practice in designing and maintaining an environment for play. Working collaboratively with members of the play and playwork team at the University of Gloucestershire, adventure playground workers explored current articulations of design intentions and practices drawing on a range of conceptual approaches and tools. This brought a critical and reflective lens to the production of the AP, its everyday rhythms, routines and habits, and the ways in which adults and children co-create play spaces
Variable Interstellar Absorption toward the Halo Star HD 219188 - Implications for Small-Scale Interstellar Structure
Within the last 10 years, strong, narrow Na I absorption has appeared at
v_sun ~ -38 km/s toward the halo star HD 219188; that absorption has continued
to strengthen, by a factor 2-3, over the past three years. The line of sight
appears to be moving into/through a relatively cold, quiescent intermediate
velocity (IV) cloud, due to the 13 mas/yr proper motion of HD 219188; the
variations in Na I probe length scales of 2-38 AU/yr. UV spectra obtained with
the HST GHRS in 1994-1995 suggest N(H_tot) ~ 4.8 X 10^{17} cm^{-2}, ``halo
cloud'' depletions, n_H ~ 25 cm^{-3}, and n_e ~ 0.85-6.2 cm^{-3} (if T ~ 100 K)
for the portion of the IV cloud sampled at that time. The relatively high
fractional ionization, n_e/n_H >~ 0.034, implies that hydrogen must be
partially ionized. The N(Na I)/N(H_tot) ratio is very high; in this case, the
variations in Na I do not imply large local pressures or densities.Comment: 12 pages; aastex; to appear in ApJ
Analytic formulas for frequency and size dependence of absorption and scattering efficiencies of astronomical polycyclic aromatic hydrocarbons
In a series of two recent papers, the frequency and size distribution
dependence of extinction spectra for astronomical silicate and graphite grains
was analyzed by us in the context of MRN type interstellar dust models. These
grains were taken to be homogeneous spheres following the power law
size distribution which is very much in use. The analytic formulas
were obtained for the graphite and silicate grains in wavelength range 1000\AA
- 22,500\AA and their utility was demonstrated. In this paper of the series, we
present analytic formulas for the scattering and absorption spectrum of another
important constituent of interstellar dust models, namely, the polycyclic
aromatic hydrocarbons (PAHs). Relative contribution of the PAHs to extinction
{\it vis a vis} carbonaceous classical grains has been examined.Comment: 19 pages, 4 figures, to appear in JQSRT 201
Recommended from our members
In vivo and in vitro assessment of mirtazapine pharmacokinetics in cats with liver disease.
BackgroundLiver disease (LD) prolongs mirtazapine half-life in humans, but it is unknown if this occurs in cats with LD and healthy cats.Hypothesis/objectivesTo determine pharmacokinetics of administered orally mirtazapine in vivo and in vitro (liver microsomes) in cats with LD and healthy cats.AnimalsEleven LD and 11 age-matched control cats.MethodsCase-control study. Serum was obtained 1 and 4 hours (22 cats) and 24 hours (14 cats) after oral administration of 1.88 mg mirtazapine. Mirtazapine concentrations were measured by liquid chromatography with tandem mass spectrometry. Drug exposure and half-life were predicted using limited sampling modeling and estimated using noncompartmental methods. in vitro mirtazapine pharmacokinetics were assessed using liver microsomes from 3 LD cats and 4 cats without LD.ResultsThere was a significant difference in time to maximum serum concentration between LD cats and control cats (median [range]: 4 [1-4] hours versus 1 [1-4] hours; P = .03). The calculated half-life of LD cats was significantly prolonged compared to controls (median [range]: 13.8 [7.9-61.4] hours versus 7.4 [6.7-9.1] hours; P < .002). Mirtazapine half-life was correlated with ALT (P = .002; r = .76), ALP (P < .0001; r = .89), and total bilirubin (P = .0008; r = .81). The rate of loss of mirtazapine was significantly different between microsomes of LD cats (-0.0022 min-1 , CI: -0.0050 to 0.00054 min-1 ) and cats without LD (0.01849 min-1 , CI: -0.025 to -0.012 min-1 ; P = .002).Conclusions and clinical importanceCats with LD might require less frequent administration of mirtazapine than normal cats
CARETS: A prototype regional environmental information system. Volume 5: Interpretation, compilation and field verification procedures in the CARETS project
The author has identified the following significant results. Level 2 land use mapping from high altitude aircraft photography at a scale of 1:100,000 required production of a photomosaic mapping base for each of the 48, 50 x 50 km sheets, and the interpretation and coding of land use polygons on drafting film overlays. To enhance the value of the land use sheets, a series of overlays was compiled, showing cultural features, county boundaries and census tracts, surface geology, and drainage basins. In producing level 1 land use maps from LANDSAT imagery, at a scale of 1:250,000 drafting film was directly overlaid on LANDSAT color composite transparencies. Numerous areas of change were identified, but extensive areas of false changes were also noted
Fe VII lines in the spectrum of RR Telescopii
Thirteen transitions within the ground 3d^2 configuration of Fe VII are
identified in ultraviolet and optical spectra of the symbiotic star RR
Telescopii obtained with the STIS instrument of the Hubble Space Telescope. The
line fluxes are compared with theoretical data computed with the recent atomic
data of K.A. Berrington et al., and high resolution optical spectra from
VLT/UVES are used to identify blends. Seven branching ratios are measured, with
three in good agreement with theory and one affected by blending. The
lambda5277/lambda4943 branching ratio is discrepant by > 3 sigma, indicating
errors in the atomic data for the lambda5277 line. A least-squares minimization
scheme is used to simultaneously derive the temperature, T, and density, N_e,
of the RR Tel nebula, and the interstellar extinction, E(B-V), towards RR Tel
from the complete set of emission lines. The derived values are: log T/K = 4.50
+/- 0.23, log N_e/cm^-3=7.25 +/- 0.05, and E(B-V)<0.27. The extinction is not
well-constrained by the Fe VII lines, but is consistent with the more accurate
value E(B-V)=0.109^{+0.052}_{-0.059} derived here from the Ne V
lambda2974/lambda1574 ratio in the STIS spectrum. Large differences between the
K.A. Berrington et al. electron excitation data and the earlier F.P. Keenan &
P.H. Norrington data-set are demonstrated, and the latter is shown to give
worse agreement with observations.Comment: To be published in Astronomy & Astrophysics; 7 pages, 4 figure
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