Now showing items 8163-8182 of 15247

    • Isolation of enteric viruses from the recreational waters of Oak Creek

      Mullinax, Rebecca Lynn.; Gerba, Charles P. (The University of Arizona., 1985)
      Enteric viruses were isolated from the fresh water recreational areas of Oak Creek in northern Arizona. Samples were collected and assayed directly for total and fecal coliforms, fecal streptococci, and coliphage. Sixty eight- to 1,155-liter samples were filtered through positively charged filters, eluted with beef extract, and assayed for human enteric viruses and rotaviruses. Enteric viruses were detected at sampling sites at levels exceeding those recommended by the State of Arizona for full-body contact recreational waters. In addition, viruses were isolated at sites which met recommended levels for fecal coliform bacteria.
    • Isolation of nucleic acid unwinding protein from Physarum polycephalum

      Scott, Paul Ethan (The University of Arizona., 1979)
    • The isolation of polyuronide materials from the hull of the soy bean, Glycine soya

      Ofner, Robert Emil, 1919- (The University of Arizona., 1942)
    • Isolation, identification, and characterization of ground water bacteria

      Stetzenbach, Linda Dale Allen,1948-; Sinclair, Norval A. (The University of Arizona., 1984)
      Ground water is an increasingly significant source of potable water and is one of the least studied ecosystems on earth. Assessment of man's impact on this resource requires knowledge of the microbial populations present. Over 500 bacteria were isolated from well water samples on a low nutrient medium (R2A). Gram-negative, rod shaped, nonmotile bacteria predominated. Acinetobacter spp. comprised 54% of the total isolates. Direct counts using ep i f 1 uorescent microscopy revealed that representative isolates grew significantly in filtered well water. Growth of Acinetobacter sp. was significantly enhanced in water enriched with low concentrations (100 ug carbon/liter or 1000 ug carbon/liter) of glucose, acetate, succinate, or pyruvate. The growth and survival of an Acinetobacter sp., an opportunistic pathogen, in water had not previously been described. Bacterial survival studies conducted on water samples from 19 wells throughout the Tucson basin revealed the presence of a significant population of bacteria capable of rapid growth and survival in unamended native well water.
    • Isotope dependence of gas laser intensity profiles

      Royce, Gerald A., 1942- (The University of Arizona., 1971)
    • Isotopes, Geochemistry, Citizen Science and Local Partnerships as Tools to Build upon a Fractured Understanding of the Hydrology of the Northern Patagonia Mountains

      McIntosh, Jennifer C.; Uhlman, Kristine; Schrag-Toso, Sean Conrad; Meixner, Thomas (The University of Arizona., 2020)
      The rural Town of Patagonia in Southeastern Arizona is facing uncertainty around the future availability of groundwater resources in the area. This uncertainty is due to extended drought and increased groundwater extraction by the mining industry in the Northern Patagonia Mountains, which are located south of the Town. To address this uncertainty, and advance the hydrologic understanding of the area, this two-phase project was formulated with partner groups working in the Patagonia area. The first phase was analysis of isotope ratios and geochemistry of springs and wells in the Northern Patagonia Mountains to better conceptualize groundwater movement within the mountain's fracture system and determine the hydrologic connectivity between the mountains and the Sonoita Creek alluvial aquifer. The results indicate that major mapped faults within the mountain block, including the Harshaw Creek Fault, appear to be conduits of groundwater movement. The Mountain Front Fault, which separates the mountains from the basin, appears to obstruct groundwater flow, resulting in distinct water chemistry and Pleistocene-aged groundwater in select areas northwest of the fault. Southeast of the fault, most mountain springs and wells produce water recharged from modern precipitation. Fossil water was found within the mountains, however, the quantity of fossil water in the mountains is unknown. Mountain front recharge and focused mountain block recharge via Harshaw Creek partially recharge the Sonoita Creek alluvial aquifer from which the Town of Patagonia pumps for its municipal water source. The results of this research indicate that drought is the primary concern for springs in the study area and the secondary concern is the resultant impact on groundwater flow in stream channel sediments around Harshaw Creek and its tributaries. This improved conceptual understanding of groundwater flow informed the second phase of this research: education on groundwater movement by means of a well owner training and recommendations for monitoring steps. Regular collection of data by the citizen science group or other stakeholder groups working in the area will allow for monitoring of groundwater resources by residents living in the watershed. Monitoring also will contribute to future hydrologic studies within the basin and will aid in making management decisions around water use by the Town Council.
    • Isotopic and chemical characterization of ground waters in the vicinity of Flagstaff, Arizona

      Wagner, Douglas Vinton,1956-; Davis, Stanley N. (The University of Arizona., 1987)
      The sustained yield of a well field adjacent to Lower Lake Mary reservoir, south of Flagstaff, Arizona, has been calculated in two separate studies, and the results differ significantly. One reason for the difference is the lack of understanding of the effect that the reservoir has on recharge to the well field. Samples were taken from various surface waters, springs, and production wells in the area surrounding Flagstaff to chemically characterize the waters and to examine the potential recharge source(s) to the Lake Mary well field. Results indicate that nearly all ground waters in the area are calcium-magnesium-bicarbonate in composition, but they differ significantly in total hardness. Isotopic values of the samples indicate that only one well within the Lake Mary well field is definitely receiving significant recharge from the reservoir.
    • Isotopic and chemical characterization of groundwater in the northern Tucson Basin, Arizona

      Pasilis, Sofie.; Long, A. (The University of Arizona., 1999)
      The chemical and isotopic characteristics of the groundwater in the Canada del Oro Valley were investigated, and existing hydrologic information compiled to determine processes affecting groundwater chemistry in this area. Evidence suggests that dissolution of calcite and cation exchange on clays are the dominant reactions occurring in the aquifer. Values of 8D and 8 180 lie within the range for winter precipitation in the Tucson Basin. Tritium data indicate that most recharge to the valley occurs along the edges of the Santa Catalina Mountains, in particular along the Canada del Oro Wash. Recharge along Big Wash appears to be minimal. Relatively high concentrations of sulfate and lower 834S values in groundwater along the Cariada del Oro Wash may be a result of historical smelting operations to the northeast of the study area.
    • Isotopic and geochemical characterization of recharge and salinity in a shallow floodplain aquifer near El Paso, Texas

      Dadakis, Jason Sophocles.; Ekwurzel, Brenda (The University of Arizona., 2004)
      The shallow alluvial aquifer of the Rio Grande floodplain near El Paso, Texas is a dynamic intermediary of recharge, discharge, and salinization processes between the deeper Hueco Bolson Aquifer and the overlying Rio Grande. Environmental tracer analyses suggest that 1) shallow aquifer groundwater is primarily of either Modern-Day Rio Grande origin or from older, less evaporated Pre-Dam Rio Grande waters, with modern local meteoric waters contributing a dominant fraction generally only near mountain fronts and 2) salinization of the Rio Grande and shallow aquifer in the southeastern portion of the Hueco Bolson is due to both near-surface agricultural impacts as well as the influx of naturally saline deep groundwater. With leakage from the shallow aquifer providing significant recharge to the deep Hueco Bolson Aquifer, any future development which may potentially decrease river infiltration must be carefully considered. Additionally, efforts to increase local irrigation efficiencies may have limited effects on water quality given the presence of natural solute sources.
    • Isotopic composition of soil carbon dioxide in the Tucson basin

      Parada, Carmen Bajos.; Davis, Stanley N.; Simpson, Eugene S. (The University of Arizona., 1981)
      Most models to correct ¹⁴C groundwater ages require the δ¹³C value of soil CO₂ which is related most of the time with the photosynthetic pathway of the vegetation cover. Samples of soil CO₂ were collected in three permanent sites in the Tucson area from July 1980 to June 1981 to determine the extent of seasonal variations and the influence of vegetation on the δ¹³C and CO₂ concentration of soil gases. The mean δ¹³C value, about -18°/₀₀, was similar to the isotopic composition of the vegetation cover. Seasonal variations were observed in both δ¹³C and CO₂ concentration. The δ¹³C variations, up to 4.5°/₀₀, seemed to be caused by exchange with atmospheric CO₂, by seasonality in plant activities and/or by changes in the δ¹³C of respired CO₂. The variations of soil CO₂ were caused by the changes in the activity of plants. Most of the CO₂ at these sites seemed to be produced by plant root respiration. Soil gas samples were also collected in the riverbeds which are the assumed recharge areas of the Tucson aquifer. Both CO₂ concentration and δ¹³C values showed changes with time and location. The mean δ¹³C for these samples was about -20°/₀₀. High concentrations of CO₂ of up to 5% were found. The source of CO₂ at these sites is most likely organic matter decomposition and plant root respiration.
    • Isotopic composition of stable carbon and carbon dioxide concentration of atmosphere in streambeds near Tombstone, Arizona

      Riddle, Jeffrey Scott.; Simpson, Eugene S. (The University of Arizona., 1984)
      Gas samples were taken at approximately a meter deep about every 30 days for a year at three sites from ephemeral streambeds of the Walnut Gulch Watershed near Tombstone, Arizona. The streambeds are composed of sands and gravels of volcanic or granitic origin and free of vegetation. Two of the sites are underlain by a conglomeritic layer from 90 cm below streambed surface to some unknown depth. The data from these two sites had CO₂ concentration values ranging from .39% vol. to .02% vol. and δ¹³C values ranging from -9.07%. to -19.02%0. The third site has no evidence of a conglomeritic layer near the streambed surface. The CO₂ concentration values ranged from .94% vol. to .29% vol. and δ¹³C values ranged from -17.53%. to -20.75%.. All δ¹³C values are with respect to PDB. Changes of CO₂ concentration and δ¹³C values were related to flood events, physical characteristics of the streambed and banks, type of bank vegetation, season, and fractionation of ¹³C and ¹²C between gaseous CO₂ and bicarbonate. Atmospheric CO₂ contributed significantly to the streambed atmosphere following flood events; the relative importance of atmospheric CO₂ diminished as a function of the ease with which root-respired CO₂ recharged a site.
    • Issues and Responses to Urban Encroachment at the Edge of Western Protected Public Lands

      Metz-Estrella, Tania M.; Pivo, Gary; Huntoon, Laura; Shaw, William (The University of Arizona., 2007)
    • Item Analysis for the Development of the Shirts and Shoes Test for 6-Year-Olds

      Plante, Elena; Tucci, Alexander; Plante, Elena; Alt, Mary; Kielar, Aneta (The University of Arizona., 2017)
      The development of a standardized assessment can, in general, be broken into multiple stages. In the first, items to be used in the assessment are generated according to the skills and abilities that are to be assessed and the needs of the developers. These items are then, ideally, tested in the field on members of the population for which the assessment is intended. Item Response Theory (IRT) analysis is used to reveal items in the item pool which are unusable due to measurement error, redundancy in the level of item difficulty, or bias. More potential items may be generated and tested until there is a set of valid items with which the developers can move forward. The present study focused on the steps of item tryout and analysis for the establishment of demonstrable item-level validity. Fifty-one potential test items were analyzed for a version of the Shirts and Shoes Test (Plante & Vance, 2012) for 6-year-olds. A total of 23 items were discarded due to error in one or more of the measures mentioned above, and one item was discarded due to its low difficulty. The remaining 27 items were deemed suitable for the 6-year-old population.