9,127 research outputs found
PROBLEMS AND POTENTIALS OF AGRICULTURAL ECONOMICS EXTENSION
Teaching/Communication/Extension/Profession,
NEBRASKA'S EXTENSION PROGRAM IN STATE AND LOCAL PUBLIC FINANCE
Teaching/Communication/Extension/Profession,
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Geologic quadrangle map no. 47
Process Steps: 1. Either: a) a Portable Document Format (PDF) version of the map provided the Bureau of Economic Geology, University of Texas at Austin was converted from pdf to Tagged Image File Format (TIFF) or b) a paper map was scanned and saved in TIFF at 200 dots per inch (dpi) and the original map size. The TIFF file was then opened in Adobe Photoshop, converted from RGB or other multiband mode to Indexed Color or Grayscale, rotated so that the top map neat line was horizontal, set to 200 dpi, and clipped to the neat lines, removing the map collar. A version with the map collar was retained. 2. Using tools within ArcGIS 10.2, both the collared and collarless Indexed Color TIF images were then either: a) georeferenced to Universal Transverse Mercator (UTM) zone 14, North American Datum 1927 (NAD27) coordinates using a digital 1:24,000 U.S. Geological Survey quadrangle index map from the Texas Natural Resources Information Services as the referencing layer or b) georeferenced to World Geodetic System 1984 (WGS84) geographic coordinates using the map corner coordinates for reference. Keyhole Markup Language (KML, KMZ) and GeoPDF map versions were created from these georeferenced maps by tools and export options in ArcGIS.
Up to five different georeferenced versions of the original map and, when available, the map pamphlet, are available for download. The versions, as distinguished by Download File name, are: 1) Mapname.pdf: a GeoPDF of the collarless map referenced to UTM zone 14 coordinates relative to the NAD27 datum. The acronym "GAT" (Geologic Atlas of Texas) indicates the source and a map original available only at a small scale (1:250,000). 2) Mapname.kmz: a KML version of the collarless map for viewing in Google Earth. The spatial reference is geographic coordinates relative to the WGS84 datum. 3) Mapname_GCSWGS84_collarless.zip: zipped files that include a collarless map in TIFF format and ancillary ArcGIS v. 10.2 georeferencing files and metadata. The spatial reference is geographic coordinates relative to the WGS84 datum. 4) Mapname_UTM_collarless.zip: a zipped file that includes a collarless map in TIFF format and ancillary ArcGIS v. 10.2 georeferencing files and metadata. The spatial reference is UTM zone 14 coordinates relative to the NAD27 datum. 5) Mapname_with_collar.zip: the same as above but with the map collar still intact. 6) Mapname_pamphlet.pdf: a copy of the map pamphlet in PDF format.
Any file name beginning with "GAT" indicates a map that was clipped from the Geologic Atlas of Texas (scale 1:250,000), the only published source for that area, and thus a much smaller-scale map than all other quadrangles.
Further metadata for each map version are available in Federal Geographic Data Committee (FGDC)-compliant metadata file within the zip files, or in the document properties of the GeoPDF and KML files when opened in Adobe Acrobat or Google Earth."For use by Barton Spring Edwards Aquifer Conservation District (BSEACD) Central Texas geologic mapping project"Scanned and georeferenced version of Barnes, V.E., 1978, Geologic map of the Round Mountain quadrangle, Blanco, Burnet, and Llano counties. Texas: University of Texas at Austin, Bureau of Economic Geology, Geologic Quadrangle Map GQ-0047, scale 1:24,000.UT Librarie
Pointless curves of genus three and four
A curve over a field k is pointless if it has no k-rational points. We show
that there exist pointless genus-3 hyperelliptic curves over a finite field F_q
if and only if q < 26, that there exist pointless smooth plane quartics over
F_q if and only if either q < 24 or q = 29 or q = 32, and that there exist
pointless genus-4 curves over F_q if and only if q < 50.Comment: LaTeX, 15 page
Color and Variability Characteristics of Point Sources in the Faint Sky Variability Survey
We present an analysis of the color and variability characteristics for point
sources in the Faint Sky Variability Survey (FSVS). The FSVS cataloged ~23
square degrees in BVI filters from ~16--24 mag to investigate variability in
faint sources at moderate to high Galactic latitudes. Point source completeness
is found to be >83% for a selected representative sample (V=17.5--22.0 mag,
B-V=0.0--1.5) containing both photometric B, V detections and 80% of the
time-sampled V data available compared to a basic internal source completeness
of 99%. Multi-epoch (10--30) observations in V spanning minutes to years
modeled by light curve simulations reveal amplitude sensitivities to
0.015--0.075 mag over a representative V=18--22 mag range. Periodicity
determinations appear viable to time-scales of an order 1 day or less using the
most sampled fields (~30 epochs). The fraction of point sources is found to be
generally variable at 5--8% over V=17.5--22.0 mag. For V brighter than 19 mag,
the variable population is dominated by low amplitude (<0.05 mag) and blue
(B-V<0.35) sources, possibly representing a population of gamma Doradus stars.
Overall, the dominant population of variable sources are bluer than B-V=0.65
and have Main Sequence colors, likely reflecting larger populations of RR
Lyrae, SX Phe, gamma Doradus, and W UMa variables.Comment: 34 pages, 16 figures, accepted in A
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