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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

The Desert Bighorn Sheep of Southeastern Utah

Irvine, Charles A. 01 May 1969 (has links)
In April, 1967, this study was begun in a 211 -square-mile area, in the rugged, arid, Red Canyon area in San Juan County, southeastern Utah. Sixteen months were spent in the field to determine the population trend, migration, distribution, and the affect of water on distribution of the bighorn sheep. No migration was documented,but seasonal shifts did occur . The shifts were due to the availability of water in the free state and in plants . Dry periods forced sheep to remain close to seeps and springs. Lambing peaked in May and was over by June . Lou lamb mortality and high numbers of yearlings indicated a growing population which is re - covering from severe mortality during the uranium boom in the 1950's. Sheep preferred browse but seasonal shifts occurred, grasses and forbs being preferred. Plants analyzed for protein proved adequate for gravid and lactating domestic ewes, and this is believed adequate for wi ld sheep. However, plants were found to be deficient in phosphorus. Parasites, disease and poisonous plants were not found to be limiting factors during the study. A 50-50 sex ratio, expec t ed in a wi ld, relatively unhunted population, was found during this study . Spermatogenesis t o some degree was evident in all trophy rams examined taken during the hunt. No biological reason to remove rams could be ascertained. Recommendations for management of the des ert bighorn sheep in s outheastern Utah include removing cattle from she e p ranges, water development and maintenance, continued ewe -lamb surveys , hunting of trophy animals, and studying a ll wild sheep populations in the state .
122

Molecular systematics and the origins of gypsophily in Nama L. (Boraginaceae)

Taylor, Sarah Elizabeth 17 July 2012 (has links)
Nama L. is a genus of approximately 50 species of herbs and subshrubs that occurs in habitats ranging from arid deserts to mesic woodlands in the New World and the Hawaiian Islands. The group has historically been divided into five or six subgeneric groups based on habitat as well as on the morphology of the anthers, styles, leaves and seeds. At least 14 species of Nama from the Chihuahuan Desert Region are either facultatively or obligately endemic to gypsum deposits. This dissertation examines interspecies relationships within Nama from a molecular phylogenetic perspective in order to evaluate historic morphology-based subgeneric classification systems of the genus and to examine the origins of facultative and obligate gypsophily within the genus. DNA sequence data from the chloroplast regions matK and ndhF and from the nuclear ribosomal region ITS were collected from 46 species of Nama as well as from four new species and several outgroups. Data were analyzed using maximum likelihood and Bayesian methods. Phylogenetic analyses recover seven strongly supported major lineages within Nama. These lineages do not correspond to traditionally recognized subgenera, although they are largely congruent with an informal system based on ultrastructural observations of seeds. Four of the seven major lineages include gypsophilous species; these range from two lineages that include a single facultative gypsophile each, to one lineage that is almost entirely comprised of gypsophiles. Gypsum endemism in general, as well as facultative and obligate gypsophily in particular, has arisen multiple times in Nama. Parametric bootstrapping rejected the hypothetical monophyly of gypsophiles across the genus as a whole and within each of the two clades that contain multiple gypsophiles. Because approximately 20 species have been described since the last major revision of Nama nearly 80 years ago, detailed morphological observations of herbarium specimens were made in order to produce a comprehensive key to the species of Nama as well as the revision of a lineage comprising eight gypsophiles and one limestone endemic. / text
123

Nitrogen cycling in irrigated crop production on hyperthermic soils within the Sonoran Desert

McGee, Eric Arthur. January 1996 (has links)
Nitrogen (N) cycling involves the gains, losses, and transformations of N from sources such as soil organic matter, crop residues, and fertilizers. These sources are the primary N supplies potentially available to non-leguminous crops. Through the use of a stable N isotope tracer (¹⁵N), transformations among various soil N pools can be studied. We conducted three separate studies using ¹⁵N. Two studies dealt with methodologies of ¹⁵N use and analysis, while the third study investigated mineralization of ¹⁵N labeled crop residues under field conditions. The first study evaluated a new apparatus for applying ¹⁵N by fertigation to subplots under buried drip irrigation. We determined that this method was an effective means of uniformly applying tracers using buried drip irrigation. The second study evaluated a new method for fine-grinding soils based on particle size distribution and variability of organic N and ¹⁵N analyses. Soils of varying texture were rapidly ground to achieve acceptable analytical precision for N and ¹⁵N analysis. The objectives of the third experiment were to: (i) evaluate mineralization of inorganic N from ¹⁵N -labeled crop residues with different C/N ratios and at different loading rates and (ii) evaluate the influence of residue loading rate and type on the percent net mineralization from ¹⁵N-labeled crop residues in a basin irrigated wheat cropping system in Southern Arizona. Mineralization of crop residues in this hyperthermic soil was rapid and was often followed by periods of re-immobilization. Net end-of-season mineralization of residue N was 30-50% for lettuce, and 30-40% for wheat.
124

Soil-plant relationships and spectroscopic properties of inositol stereoisomers: the identification of D-chiro- and muco-inositol in a desert soil-plant system

L'Annunziata, Michael F. January 1970 (has links)
No description available.
125

Chemical composition of the essential oils from certain native plants of the Southwestern desert

McCaughey, William Frank, 1921- January 1951 (has links)
No description available.
126

Perennial vegetation associated with the organpipe cactus in Organ Pipe Cactus National Monument, Arizona

Mulroy, Thomas Wilkinson, 1946- January 1971 (has links)
No description available.
127

Estimation of desert rodent populations by intensive removal

Olding, Ronald James, 1947- January 1976 (has links)
No description available.
128

EXTRACTION, CHARACTERIZATION AND FUNCTIONAL PROPERTIES OF JOJOBA PROTEINS

Cardoso, Fernando Antonio January 1980 (has links)
Two defatted jojoba seed meals were prepared; one using whole seeds (JM), and the other from which seed coats were removed prior to extraction of the oil (DJM). The protein content of both meals was about 24%. The proteins from JM and DJM were extracted according to their solubility in water, dilute saline, alcohol, and alkali solutions. These extractions produced the albumin, globulin, prolamine and glutelin protein concentrates. The major concentration of proteins in jojoba were the albumin (65%) and globulin (21%) fractions. The amino acid compositions of both JM and DJM were found to be very similar. Methionine was the limiting amino acid in jojoba seed proteins. The protein composition was determined, and the molecular weight was estimated through chromatographic analysis using gel filtration on Sephadex G-100 and ion-exchange chromatography on DEAE-Sephadex and CM-Sephadex. At least 5 separate protein fractions in each of the albumin and globulin concentrates and 8 separate protein fractions in each of the prolamine and glutelin concentrates were found. The molecular weights of jojoba protein concentrates varied from 19,000 to 150,000 for albumins, from 18,000 to 128,800 for globulins, from 11,700 to 141,200 for prolamines, and from 29,500 to 150,000 for glutelins. All protein concentrates showed very good fat absorption and solubility at values of pH below 3.0 and above 4.0. Albumins and globulins showed very good foamability and emulsion properties. The prolamine and glutelin concentrates showed very poor foamability and emulsion properties. The buffering capacity of jojoba protein concentrates was very low.
129

SOIL MICROBIAL BIOMASS AS INDICATED BY EXTRACTABLE ADENOSINE-TRIPHOSPHATE

Conklin, Alfred Russel, 1941- January 1972 (has links)
No description available.
130

A study of the thermotolerant heterotrophic microorganisms in desert soil

Trautman, Robert John, 1917- January 1953 (has links)
No description available.

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