IDENTIFYING COST-EFFECTIVE SOURCES FOR WATER TRANSFERS FROM AGRICULTURE TO ENDANGERED SPECIES PRESERVATION IN THE PLATTE RIVER BASIN

Resource /Energy Economics and Policy,

BENEFITS OF CONTROLLING SALINE WATER IN COLORADO

The Arkansas River in Colorado is confronted with a salinity issue; the majority of this salinity problem is due to agricultural runoff caused by irrigation. Reducing applications of irrigation water through adoption of more technically efficient irrigation systems is one means of improving water quality in the Arkansas River basin. This research uses positive mathematical programming to model the cropping practices of the farms along the Arkansas River. It examines the affect of acreage and profit levels of these farms given the choice of changing their irrigation technologies.Environmental Economics and Policy,

Real-Time Measurement of Lung Motion for CT Guided Lung Biopsies

The objective of this project is to develop a device that allows a physician to view and measure real time lung motion of a patient inside a CT scanner during lung biopsy. This will increase time efficiency and accuracy of lung tumor treatment CT procedures, as this device will enable the collection of clear and meaningful scans. With this application, size and simplicity are of the utmost importance, as the device must be as practical as possible. Given these constraints the design involves a low profile, low volume sensor to measure data while physically attached to the patient’s bed, and a computer base station graphical user interface which receives the data wirelessly. The interface of this base station, as viewed by the physician, displays a live graph of the lung displacement - accurate within 0.18 ms and 2 mm. This device will not only allow doctors to biopsy lung lesions more efficiently, but will also reduce radiation exposure to the patient by avoiding repeated scans. The device will work in tandem with the CT scan; the device triggering the scan to be taken when the patient’s lungs are held in the desired position. This procedure will help to minimize healthy tissue damage and to streamline the treatment process by reducing the amount of X-ray scans needed, thus positively impacting patient recovery time and overall process effectiveness.https://scholarscompass.vcu.edu/capstone/1189/thumbnail.jp

Tides and Overtides in Long Island Sound

Using observations obtained by acoustic Doppler profilers and coastal water level recorders, we describe the vertical and horizontal structure of the currents and sea level due to the principal tidal constituents in Long Island Sound, a shallow estuary in southern New England. As expected, the observations reveal that M2 is the dominant constituent in both sea surface and velocity at all depths and sites. We also find evidence that the vertical structure of the M2 tidal current ellipse parameters vary with the seasonal evolution of vertical stratification at some sites. By comparing our estimates of the vertical structure of the M2 amplitudes to model predictions, we demonstrate that both uniform and vertically variable, time invariant eddy viscosities are not consistent with our measurements in the Sound. The current records from the western Sound contain significant overtides at the M4 and M6 frequencies with amplitudes and phases that are independent of depth. Though the M4 amplitude decreases to the west in proportion to M2, the M6 amplifies. Since the dynamics that generate overtides also produce tidal residuals, this provides a sensitive diagnostic of the performances of numerical circulation models. We demonstrate that the observed along-Sound structure of the amplitude of the M4 and M6 overtides is only qualitatively consistent with the predictions of a nonlinear, laterally averaged layer model forced by a mean flow and sea level at the boundaries. Since neither the vertical structure of the principal tidal constituent nor the pattern of horizontal variation of the largest overtides can be explained using well established models, we conclude that they are fundamentally inadequate and should no longer be used for more than a basic qualitative understanding, and even then should be used with caution. We provide comprehensive tables of the tidal current parameters to facilitate the critical evaluation of future models of the circulation in the Sound

Target selection for the SUNS and DEBRIS surveys for debris discs in the solar neighbourhood

Debris discs - analogous to the Asteroid and Kuiper-Edgeworth belts in the Solar system - have so far mostly been identified and studied in thermal emission shortward of 100 um. The Herschel space observatory and the SCUBA-2 camera on the James Clerk Maxwell Telescope will allow efficient photometric surveying at 70 to 850 um, which allow for the detection of cooler discs not yet discovered, and the measurement of disc masses and temperatures when combined with shorter wavelength photometry. The SCUBA-2 Unbiased Nearby Stars (SUNS) survey and the DEBRIS Herschel Open Time Key Project are complimentary legacy surveys observing samples of ~500 nearby stellar systems. To maximise the legacy value of these surveys, great care has gone into the target selection process. This paper describes the target selection process and presents the target lists of these two surveys.Comment: 67 pages with full tables, 7 figures, accepted to MNRA

ASAS Light Curves of Intermediate Mass Eclipsing Binaries and the Parameters of HI Mon

We present a catalog of 56 candidate intermediate mass eclipsing binary systems extracted from the 3rd data release of the All Sky Automated Survey. We gather pertinent observational data and derive orbital properties, including ephemerides, for these systems as a prelude to anticipated spectroscopic observations. We find that 37 of the 56, or ~66% of the systems are not identified in the Simbad Astronomical Database as known binaries. As a specific example, we show spectroscopic data obtained for the system HI Mon (B0 V + B0.5 V) observed at key orbital phases based on the computed ephemeris, and we present a combined spectroscopic and photometric solution for the system and give stellar parameters for each component.Comment: 83 pages, 63 figure

Radial Distribution of Dust Grains Around HR 4796A

We present high-dynamic-range images of circumstellar dust around HR 4796A that were obtained with MIRLIN at the Keck II telescope at lambda = 7.9, 10.3, 12.5 and 24.5 um. We also present a new continuum measurement at 350 um obtained at the Caltech Submillimeter Observatory. Emission is resolved in Keck images at 12.5 and 24.5 um with PSF FWHM's of 0.37" and 0.55", respectively, and confirms the presence of an outer ring centered at 70 AU. Unresolved excess infrared emission is also detected at the stellar position and must originate well within 13 AU of the star. A model of dust emission fit to flux densities at 12.5, 20.8, and 24.5 um indicates dust grains are located 4(+3/-2) AU from the star with effective size, 28+/-6 um, and an associated temperature of 260+/-40 K. We simulate all extant data with a simple model of exozodiacal dust and an outer exo-Kuiper ring. A two-component outer ring is necessary to fit both Keck thermal infrared and HST scattered-light images. Bayesian parameter estimates yield a total cross-sectional area of 0.055 AU^2 for grains roughly 4 AU from the star and an outer-dust disk composed of a narrow large-grain ring embedded within a wider ring of smaller grains. The narrow ring is 14+/-1 AU wide with inner radius 66+/-1 AU and total cross-sectional area 245 AU^2. The outer ring is 80+/-15 AU wide with inner radius 45+/-5 AU and total cross-sectional area 90 AU^2. Dust grains in the narrow ring are about 10 times larger and have lower albedos than those in the wider ring. These properties are consistent with a picture in which radiation pressure dominates the dispersal of an exo-Kuiper belt.Comment: Accepted by Astrophysical Journal (Part1) on September 9, 2004. 13 pages, 10 figures, 2 table

The Lick-Carnegie Survey: A New Two-Planet System Around the Star HD 207832

Keck/HIRES precision radial velocities of HD 207832 indicate the presence of two Jovian-type planetary companions in Keplerian orbits around this G star. The planets have minimum masses of 0.56 and 0.73 Jupiter-masses with orbital periods of ~162 and ~1156 days, and eccentricities of 0.13 and 0.27, respectively. Stromgren b and y photometry reveals a clear stellar rotation signature of the host star with a period of 17.8 days, well separated from the period of the radial velocity variations, reinforcing their Keplerian origin. The values of the semimajor axes of the planets suggest that these objects have migrated from the region of giant planet formation to closer orbits. In order to examine the possibility of the existence of additional (small) planets in the system, we studied the orbital stability of hypothetical terrestrial-sized objects in the region between the two planets and interior to the orbit of the inner body. Results indicated that stable orbits exist only in a small region interior to planet b. However, the current observational data offer no evidence for the existence of additional objects in this system.Comment: 23 pages, 4 figures, 5 tables, accepted for publication in Ap