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Population Regulation Of The Jackson Elk Herd, Bruce L. Smith

Aspen Bibliography

No abstract provided.

Habitat Selection By Lacustrine Rainbow Trout Within Gradients Of Temperature, Oxygen, And Food Availability, Chris Luecke, D. Teuscher

Watershed Sciences Faculty Publications

Rainbow trout (Oncorhynchus mykiss [Walbaum]) in Castle Lake, California were concentrated at certain depths during day and evening hours. A fish bioenergetics simulation model based on vertical gradients of temperature, oxygen concentration, and food availability indicated that rainbow trout selected habitats that maximized growth rate. In 1 of the 2 years of study, a strong pattern of diel vertical migration of rainbow trout was evident and was associated with vertical migrations of daphnids in the lake. The simulation model correctly predicted the occurrence and magnitude of fish migration. During the day some trout resided at depths with little potential for …

Utah Water Research Laboratory Publications Listing 1989-1994, David S. Bowles, Leaunda S. Hemphill

Reports

No abstract provided.

A Spatially Distributed Energy Balance Snowmelt Model, David G. Tarboton, Tanveer G. Chowdhury, Thomas H. Jackson

Reports

This paper describes an energy balance snowmelt model developed for the prediction of rapid snowmelt rates responsible for soil erosion and water input to a distributed water balance model. The model uses a lumped representation of the snowpack with two state variables, namely, water equivalent and energy content relative to a reference state of water in the ice phase at 0 degrees Celcius. This energy content is used to determine snowpack average temperature of liquid fraction. This representation of the snowpack is used to determine snowpack average temperature of liquid fraction. This representation of the snowpack is used in a …

Measurements And Modeling Of Snow Energy Balance And Sublimation From Snow, David G. Tarboton

Reports

Snow melt runoff is an important factor in runoff generation for most Utah rivers and a large contributer to Utah's water supply and periodically flooding. The melting of snow is driven by fluxes of energy into the snow during warm periods. These consist of radiant energy from the sun and atmosphere, sensible and latent heat transfers due to turbulent energy exchanges at the snow surface and a relatively small ground flux from below. The turbulent energy exchanges are also responsible for sublimation from the snow surface, particularly in arid environments, and result in a loss of snow water equivalent available …

The Source Hydrology Of Severe Sustained Drought In Th Southwestern U.S., David G. Tarboton

Reports

This paper considers the risk of drought and develops drough scenarios for use in the study of severe sustained drought in the Southwestern United States. The focus is on the Colorado River gbasin and regions to which Colorado River water is exported, especially southern California, which depends on water from the Colorado River as well as the four major rivers in northern California. Drought scenarios are developed using estimates of unimpaired historic streamflow as well as reconstructions of streamflow based on tree ring widths. Drought scenarios in the Colorado River are defined on the basis of annual flow at Lees …

Hycrest Crested Wheatgrass Accelerates The Degradation Of Pentachlorophenol In Soil, A. Ferro, Ronald C. Sims, B. Bugbee

Biological Engineering Faculty Publications

We investigated the effects of vegetation on the fate of pentachlorophenol (PCP) in soil using a novel high-flow sealed test system. Pentachlorophenol has been widely used as a wood preservative, and this highly toxic biocide contaminates soil and ground water at many sites. Although plants are known to accelerate the rates of degradation of certain soil contaminants, this approach has not been thoroughly investigated for PCP. The fate of [14C]PCP, added to soil at a concentration of 100 mg/kg, was compared in three unplanted and three planted systems. The plant used was Hycrest, a perennial, drought-tolerant cultivar of crested wheatgrass …

Introducing Uncertainty Of Aquifer Parameters Into An Optimization Model, Robert L. Ward, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

A stochastic analysis is made for a previously described groundwater contaminant management model {Peralta and Ward, 1988). The stochastic model is based on incorporating uncertainty of the aquifer parameters transmissivity and effective porosity into the model. This is accomplished by finding the partial derivative of drawdown with respect to each of these parameters using a Taylor series expansion approximation of the Theis equation. Input that is required for the stochastic version is the mean of the transmissivity and effective porosity, the coefficient of variation of the transmissivity and effective porosity, and a reliability level (0%-100%) . The reliability is a …

Optimizing Irrigation Management For Pollution Control And Sustainable Crop Yield, Ghassan R. Musharrafieh, Richard C. Peralta, Ronald J. Hanks, Lynn M. Dudley

Civil and Environmental Engineering Faculty Publications

Irrigation strategies which maximize crop yield while maintaining target salt concentration in the root zone and/or prevent salt from leaching to the groundwater are computed using a nonlinear, one dimensional, simulation/optimization management model. The included constraint equations maintain a water volume balance and salt transport in the unsaturated zone. Utilized are implicit finite difference forms of the nonlinear, unsteady, unsaturated water flow equation (Richards's equation), and the diffusion-convection solute transport equation. Other constraints include nonlinear functions describing the hydraulic properties of the medium (hydraulic conductivity as a function of matric potential, volumetric water content as a function of matric potential, …

Preventing Pesticide Contamination Of Groundwater While Maximizing Irrigated Crop Yield, Richard C. Peralta, M. A. Hegazy, G. Musharrafieh

Civil and Environmental Engineering Faculty Publications

A simulation/optimization model is developed for maximizing irrigated crop yield while avoiding unacceptable pesticide leaching. The optimization model is designed to help managers prevent non-point source contamination of shallow groundwater aquifers. It computes optimal irrigation amounts for given soil, crop, chemical, and weather data and irrigation frequencies. It directly computes the minimum irrigated crop yield reduction needed to prevent groundwater contamination. Constraint equations used in the model maintain a layered soil moisture volume balance; describe percolation, downward unsaturated zone solute transport and pesticide degradation; and limit the amount of pesticide reaching groundwater. Constraints are linear, piecewise linear, nonlinear, and exponential. …

Physical And Functional Characteristics Of Cellclumping In Lactose-Positive Transconjugants Of Lactococcus Lactis Ssp. Lactis Ml3, H. Wang, Jeff Broadbent, J. K. Kondo

Nutrition, Dietetics, and Food Sciences Faculty Publications

Transconjugants of Lactococcus lactis ssp. lactis ML3 that acquire the ability to utilize lactose often exhibit self-aggregation and become able to transfer the ability to utilize lactose at frequencies 102 to 105 times higher than strain ML3. Our laboratory investigated the physical and functional characteristics of cell aggregation in ML3 transconjugants. Results showed that donor cell auto-aggregation was dissociated when cells were suspended in buffers that contained EDTA or when they were briefly exposed to proteinase K or α-chymotrypsin. Conjugation studies revealed that disruption of donor cell aggregation substantially decreased the efficiency of lactose plasmid transfer. Dissociation by EDTA or …

Raccoons: Wildlife Damage Management Series, C. M. Huxoll, Terry A. Messmer, Michael R. Conover

Wildland Resources Faculty Publications

Raccoons (Procyon lotor) are found across the United States largely due to their excellent ability to adapt and take advantage of new habitats. Raccoons, although not native to Utah, are abundant throughout much of the state. They are most commonly found in wooded areas along rivers, marshes or lakes. In urban areas, raccoons will make dens in attics, chimneys, under houses, in abandoned buildings, and in woodpiles.

Effects Of Ionizing Radiation On The Size Distribution Of Proteoglycan Aggregates Synthesized By Chondrocytes In Agarose, M. Cornelissen, H. Thierens, L. De Ridder

Scanning Microscopy

Effects of ionizing radiation on the structure and size-distribution of newly synthesized proteoglycan aggregates are studied in-vitro. Chondrocytes, isolated from embryonic chick sterna, are cultured for 7 days in a tri-dimensional agarose system. Single radiation doses of 10, 20 and 50 Gy are given before starting the culture. Digestion of the artificial agarose matrix liberates the newly synthesized proteoglycans. Spreading with cytochrome C allows electron microscopic investigations of the individual, newly synthesized molecules.

The structure of aggregates synthesized by control and irradiated chondrocytes is comparable. However, radiation causes alterations in the size-distributions of the aggregate-populations. For the control cultures, an …

Investigation Of Dislocations In Gaas Using Cathodoluminescence In The Scanning Electron Microscope, K. L. Pey, J. C. H. Phang, D. S. H. Chan

Scanning Microscopy

Electrically active dislocations in Si-doped {100} GaAs substrates were observed using the cathodoluminescence (CL) technique in the scanning electron microscope (SEM). CL contrast profiles were experimentally obtained from the dislocations at different beam energies. Based on the CL model for localized defects in semiconductors developed earlier by Pey, the depths of the dislocations were found by locating the beam energy at which maximum CL contrast occurred. A preferential etching technique for {100} GaAs was employed to reveal the dislocations and to measure their depths. The etched depths obtained were compared to the predicted results from the theoretical model developed. The …

Imaging-Sims (Secondary Ion Mass Spectroscopy) Studies Of Advanced Materials, R. Levi-Setti, J. M. Chabala, J. Li, K. L. Gavrilov, R. Mogilevsky, K. K. Soni

Scanning Microscopy

This article describes the application of scanning ion microprobe (SIM) microanalysis for the characterization of advanced engineered materials. In conjunction with secondary ion mass spectrometry (SIMS), scanning ion microprobes can image elemental distributions over surfaces with high lateral resolution (50-100 nm). With this technique, most elements, including isotopes, can be detected with good sensitivity. The principles and instrumentation associated with the SIM/SIMS technique are briefly described and ongoing developments are outlined. The analytical capabilities of the technique are illustrated by case studies of aluminum-lithium alloys, zinc oxide varistors, aluminum matrix composites, and photographic materials.

Improved Visualization Of Dna In Aqueous Buffer With The Atomic Force Microscope, Magdalena Bezanilla, Carlos J. Bustamante, Helen G. Hansma

Scanning Microscopy

An improved method has been developed for imaging deoxyribonucleic acid (DNA) in aqueous buffer with the atomic force microscope (AFM). DNA on untreated mica can be imaged in aqueous buffer with the AFM if the DNA is deposited onto the mica in a buffer with HEPES and MgCl₂, if the sample is rinsed thoroughly with high water pressure, and if the imaging is done with an electron beam-deposited (EBD) tip that has been deposited in the scanning electron microscope (SEM). The water rinse removes DNA that is otherwise easily scraped off the substrate. There is evidence that sharper …

Quantitative Elemental Mapping Of Biomedical Specimens Using The Nuclear Microprobe., Jan Pallon, John Knox

Scanning Microscopy

Quantitative and structural elemental information is available from the nuclear microprobe through a time consuming fit of the (X-ray) spectrum at each point. An alternative technique is proposed which greatly shortens the analysis procedure and allows an increased number of samples to be processed. The method discussed here is to create elemental maps which, when they are divided by the charge/pixel and multiplied by a scaling factor, will form quantitative maps. The scaling factors are obtained from a calibration procedure comparing a large number of fitted X-ray spectra with the corresponding contents of selected energy windows. The technique also allows …

Ischemia/Reperfusion Injury Of The Ascending Colon In Ponies: A Correlative Study Utilizing Microvascular Histopathology And Corrosion Casting, B. J. Darien, P. A. Sims, W. C. Stone, D. R. Schilly, R. R. Dubielzig, R. M. Albrecht

Scanning Microscopy

Volvulus of the ascending colon (ACV) in the horse results in microvascular injury and necrosis of the intestinal mucosa. This study investigated the site and type of microvascular injury which occurs within the mucosa and sub mucosa following ACV. Histopathology of volvulus treated ponies demonstrated mucosa! necrosis with microvascular hemorrhage and thrombosis. Thrombi occurred within the subepithelial capillaries and edema and hemorrhage developed throughout the mucosa and submucosa. Vascular casts allowed 3-D viewing of samples obtained from the entire pelvic flexure and demonstrated two distinct microvascular changes: 1) disruption of the colonic glandular capillary network occurred concomitantly with the …

X-Ray Microanalysis Of Camp-Induced Ion Transport In Ncl-Sg3 Sweat Gland Cells, Ann-Christin Mörk, Godfried M. Roomans

Scanning Microscopy

cyclic AMP (cAMP)-induced ion transport in a human sweat gland cell line, NCL-SG3, was investigated by X-ray microanalysis. Stimulation with cAMP caused a decrease in cellular Cl and K content in cells grown on impermeable as well as permeable supports. In cells grown on plastic coverslips or Transwell inserts stimulation with cAMP caused a significant decrease of the Na concentration, but no significant effect on the intracellular Na was seen on cells grown on grids. cAMP had no significant effect on the intracellular Ca concentration.

Caesium On Si(100) Studied By Biassed Secondary Electron Microscopy, M. Azim, C. J. Harland, T. J. Martin, R. H. Milne, J. A. Venables

Scanning Microscopy

An ultra-high vacuum scanning electron microscope (UHV-SEM) has been used to study sub-monolayers of Cs on Si(100) surface. Cs adsorption on the surface causes a considerable change in the work function. Coverages below 1/2 monolayer (ML) have been estimated by correlating the work function changes with the secondary electron (SE) signal. It has been found that this signal is sensitive down to ~ 0.005 ML when the sample is biassed to a few hundred volts.

Electron trajectories from a biassed sample have been simulated for electrons originating from different areas with different work functions across the sample. This indicates that …

Calcium Phosphate In Aspergillosis Of The Maxillary Sinus, Hidekuni Tanaka, Toshiro Sakae, Hiroyuki Mishima, Hirotsugu Yamamoto

Scanning Microscopy

The unique appearance of apatite in fungus balls of aspergillosis in the maxillary sinus was investigated using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray microdiffraction and Fourier transform infrared spectroscopy (FT-IR). Rod-shaped fragments with tubular structures, and globular vesicles covered with conidia were observed in the fungus balls. Massive fragments of a solid substance were demonstrated inside the fungus balls. Calcium and phosphate were detected in necrotic areas of the fungus balls by EDS. X-ray microdiffraction and FT-IR showed the presence of an apatite-like substance, but failed to demonstrate the presence of calcium oxalate crystals usually found in such …

Effects Of Modulated And Continuous Microwave Irradiation On Pyroantimonate Precipitable Calcium Content In Junctional Complex Of Mouse Small Intestine, Z. Somosy, G. Thuróczy, J. Kovács

Scanning Microscopy

The pyroantimonate precipitable calcium content of intestinal epithelial cells was investigated in mice following total body irradiation with 2450 MHz continuous and low frequency (16 Hz) square modulated waves. In the control animals the reaction products appeared in the intercellular space of adjacent cells including intermediate junctions and desmosomes and were absent in the area of tight junctions. Immediately after low frequency modulated microwave irradiation at 0.5 and 1mW/cm² power densities, a rapid distribution of pyroantimonate precipitable calcium content was observed. The pyroantimonate deposits were located on the cytoplasmic side of lateral membrane, in the area of junctional complex, …

Optimization And Application Of Jet-Freezing, T. Müller, S. Moser, M. Vogt, C. Daugherty, M. V. Parthasarathy

Scanning Microscopy

Cryofixation is considered to be the best method for immobilizing biological material in its natural state. In jet-freezing, the specimen typically is sandwiched between two carriers and kept in place while a coolant is moved very rapidly against the opposite surfaces. The JFD 030 jet-freezing device has been used to optimize the operating parameters. The course of the temperature in place of a specimen was measured with thermocouples and recorded by an IBM-compatible personal computer using a specifically developed software program. Mean cooling rates, over the temperature range of 273K to 173K, achievable with different cryogens, including the non-flammable HCFC …

Scanning Electron Microscopy Of High-Pressure-Frozen Sea Urchin Embryos, Paul Walther, Ya Chen, Marek Malecki, Sara L. Steffen Zoran, Gerald P. Schatten, James B. Pawley

Scanning Microscopy

High-pressure-freezing permits direct cryo-fixation of sea urchin embryos having a defined developmental state without the formation of large ice crystals. We have investigated preparation protocols for observing high-pressure-frozen and freeze-fractured samples in the scanning electron microscope. High-pressure-freezing was superior to other freezing protocols, because the whole bulk sample was reasonably well frozen and the overall three-dimensional shape of the embryos was well preserved. The samples were either dehydrated by freeze-substitution and critical-point-drying, or imaged in the partially hydrated state, using a cold stage in the SEM. During freeze-substitution the samples were stabilized by fixatives. The disadvantage of this method was …

Micro-Pixe (Particle Induced X-Ray Emission) Analysis Of Aluminum In Rat-Liver Using Mev Heavy Ion Microprobes, Yuji Horino, Yoshiaki Mokuno, Atsushi Kinomura, Kanenaga Fujii, Sakae Yumoto

Scanning Microscopy

Heavy ion microprobes (HIM) such as 3 MeV Si²⁺ and 3 MeV p²⁺ have been applied to the elemental analysis by PIXE (proton-induced X-ray emission). It was found that silicon and phosphorus microprobes have several times higher sensitivity for aluminum Kα X-rays than 2 MeV proton microprobes, and detection limits were more favorable in a phosphorus microprobe. Using a 3 MeV p²⁺ microprobe, the liver of a rat, which had been injected with aluminum-lactate, was investigated and it was found that aluminum segregates in areas with a dimension of about 10 μm. These areas could hardly be …

Intracellular And Extracellular Elemental Composition Of The Endolymphatic Sac Studied By X-Ray Microanalysis, Romuald Wroblewski

Scanning Microscopy

X-ray microanalysis was performed along with light microscopy (LM) on rapidly frozen and cryo-sectioned endolymphatic sac tissues of adult guinea pigs, to determine the elemental composition of the different cell types in this tissue as well as the content of the sac lumen. The morphological preservation and spatial resolution of cryo-sectioned endolymphatic sac was found adequate for the identification of the different cell types of the sac in the transmission electron microscope. Further cell type identification was performed by comparing scanning transmission electron microscopy images with LM images on adjacent serial sections. X-ray microanalysis demonstrated differences between epithelial and sub-epithelial …

Modeling Technique For Optimal Recovery Of Immiscible Light Hydrocarbons As Free Product From Contaminated Aquifer, Grant S. Cooper Jr., Richard C. Peralta, Jagath J. Kaluarachchi

Civil and Environmental Engineering Faculty Publications

Contamination sites associated with light non-aqueous phase liquids {LNAPL) are numerous and represent difficult cleanup problems. Remediation methods for cleanup of LNAPL fluids in subsurface systems are continuously evolving with the development of various technologies for pump.-and~treat, soil venting, and in-situ bioremediation. Evaluating the effectiveness of remediation techniques as well as attempting to improve their efficiency has been a focus of many researchers, These efforts have included the development of computer simulation models to predict and analyze the fluid movement, entrapment, and mobilization of three~phase systems in porous media. The capability of computer models that not only simulate but optimize …

Insights, Fall, 1993, Utah State University

Discovery Magazine

Bi-annual alumni newsletter for the College of Science of Utah State University in Logan.

Migration Of Epithelium During Phenytoin-Dependent Gingival Overgrowth In Mice, S. H. Ashrafi, B. Atassi, R. Erickson, T. Sabet

Scanning Microscopy

A small cavity was made in the mesiopalatal area of the maxillary first molar adjacent to the gingiva. Mice were maintained on 40 mg/kg phenytoin (or on diluent for control) by daily intraperitoneal injections. After 9 weeks, light microscopic observations revealed that in experimental mice, epithelial cells migrated towards the cavity and covered it. In controls, epithelial cell migration towards the cavity did not occur. For scanning electron microscopic (SEM) studies, specimens were fixed in 4% glutaraldehyde in 0.1 M phosphate buffer, pH 7.2, for 2 hours, dehydrated, critical point dried and coated with gold. The surface of the outer …

Technical Improvements In Corrosion Casting Of Small Specimens: A Study On Mesonephric Tubules And Vessels Of Chicken Embryos, A. Carretero, H. Ditrich, M. Navarro, H. Splechtna, J. Ruberte

Scanning Microscopy

The injection technique for corrosion casting of small, embryonic material can be improved by using a "chemical ligature" (cyanocrylate). With this simple method, leakage of the resin at the injection site is prevented and the mechanical stability of the cannula-vessel coupling is improved.

The blood vascular system of chicken embryos as small as Hamburger-Hamilton stage 24 (approximately 4.5 days of incubation) has successfully been injected using this procedure. Corrosion casts of the mesonephric tubular system have been made in a similar manner. Additionally, a simple way for secure transport of the fragile casts by immersion in 10% gelatin is suggested.