Digital Commons Network^™

Stand Hazard Rating For Central Idaho Forests, Robert Steele, Ralph E. Williams, Julie C. Weatherby, Elizabeth D. Reinhardt, James T. Hoffman, R. W. Thier

Aspen Bibliography

No abstract provided.

Fire-Bgc--A Mechanistic Ecological Process Model For Simulating Fire Succession On Coniferous Forest Landscapes Of The Northern Rocky Mountains, Robert E. Keane, Penelope Morgan, Steven W. Running

Aspen Bibliography

An ecological process model of vegetation dynamics mechanistically simulates long-term stand dynamics on coniferous landscapes of the Northern Rocky Mountains. This model is used to investigate and evaluate cumulative effects of various fire regimes, including prescribed burning and fire exclusion, on the vegetation and fuel complex of a simulation landscape composed of many stands. Detailed documentation of the model FIRE-BGC (a FIRE BioGeoChemical succession model) with complete discussion of all model parameters is followed with results of an application of the FIRE-BGC to a whitebark pine landscape in the Bob Marshall Wilderness Complex. Simulation results of several management scenarios are …

Waste-Wood-Derived Fillers For Plastics, Brent English, Craig M. Clemons, Nicole Stark, James P. Schneider

Aspen Bibliography

Filled thermoplastic composites are stiffer, stronger, and more dimensionally stable than their unfilled counterparts. Such thermoplastics are usually provided to the end-user as a precompounded, pelletized feedstock. Typical reinforcing fillers are inorganic materials like talc or fiberglass, but materials derived from waste wood, such as wood flour and recycled paper fiber, are also effective as fillers. The goal of this project was to generate commercial interest in using waste-wood–paper-derived fillers (WPFs) to reinforce thermoplastics. The research strategy was twofold: developmental research and outreach. Specific objectives were (1) to improve wastepaper fiber preparation, feeding, and compounding methods, and optimize composite performance, …

Effects Of Daphnia Availability On Growth And Food Consumption Of Rainbow Trout In Two Utah Reservoirs, R. Tabor, Chris Luecke, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

We monitored the diet and growth of stocked rainbow trout Oncorhynchus mykiss in two Utah reservoirs during 1986 and 1989–1990. For the first month after stocking, juvenile rainbow trout in both reservoirs fed extensively on large Daphnia spp. In East Canyon Reservoir where Daphnia were abundant, this pattern continued throughout the summer, fall, and winter. Growth of rainbow trout in East Canyon Reservoir was generally good throughout 1989–1990. In Causey Reservoir, where Daphnia were less abundant and smaller, rainbow trout fed progressively less on smaller Daphnia throughout the summer, fall, and winter, while other prey items (snails, aquatic insects, and …

Soldier's Guide To Wildlands Of Camp W. G. Williams, Thomas Hysell, Margaret Pettis

Aspen Bibliography

No abstract provided.

The Social Context Of Ecosystem Management: Unanswered Questions And Unresolved Issues, Mark W. Brunson

Environment and Society Faculty Publications

No abstract provided.

Mutations In Trans-Acting Factors Affecting Mrna Decapping In Saccharomyces Cereviciae, Lianna K. Etchberger, C. A. Stevens, A. Stevens, R. Parker

Biology Faculty Publications

The decay of several yeast mRNAs occurs by a mechanism in which deadenylation precedes decapping and subsequent 5'-to-3' exonucleolytic decay. In order to identify gene products required for this process of mRNA turnover, we screened a library of temperature-sensitive strains for mutants with altered mRNA degradation. We identified seven mutations in four genes that inhibited mRNA turnover. Two mutations were alleles of the XRN1 5'-to-3' exoribonuclease known to degrade mRNAs following decapping. One mutation defined a new gene, termed DCP1, which in subsequent work was demonstrated to encode a decapping enzyme or a necessary component of a decapping complex. The …

Fate Of Biological Control Introductions: Monitoring An Australian Fungal Pathogen Of Grasshoppers In North America, Michael J. Bidochka, Scott R. A. Walsh, Mark E. Ramos, Raymond J. St. Leger, Julie Cl Silver, Donald W. Roberts

Biology Faculty Publications

In North America there are two generally recognized pathotypes (pathotypes 1 and 2) of the fungus Entomophaga grylli which show host-preferential infection of grasshopper subfamilies. Pathotype 3, discovered in Austra- lia,hasabroadergrasshopperhostrangeandwasconsidered to be a good biocontrol agent. Between 1989 and 1991 patho- type3wasintroducedattwofieldsitesinNorthDakota.Since resting spores are morphologically indistinguishable among pathotypes, we used pathotype-specific DNA probes to con- firm pathotype identification in E. grylli-infected grasshop- pers collected at the release sites in 1992, 1993, and 1994. In 1992, up to 23% of E. grylli-infected grasshoppers of the subfamilies Melanoplinae, Oedipodinae, and Gomphocerinae were infected by pathotype 3,with no infections >1 km …

Utah Water Research Laboratory Publications Listing 1993-1996, David S. Bowles, Leaunda S. Hemphill

Reports

No abstract provided.

Stress Corrosion And Stress Induced Surface Morphology Of Epitaxial Films, Michael Grinfeld

Scanning Microscopy

In addition to several new predictions, the general theory of thermodynamic stability of heterogeneous systems with rearrangement has allowed us to understand the roots of several experimental and theoretical results of the past. One of them is an outstanding paper of Asaro and Tiller on stress corrosion cracking by surface diffusion published two decades ago. We compare results of Asaro and Tiller with conclusions of thermodynamic theory of solids with rearrangement and develop some Asaro-Tiller results in the directions dictated by the needs of thin films technology and experiment. A surface diffusion model in a prestressed elastic solid is studied …

Utilization Of An Electron-Beam Tester For Determining Internal Electric Field Profiles In Micro-Structured Thin-Film Semiconductor Devices, A. Jank, M. Jung, M. Lambert, G. Lichter, H. Schmoranzer

Scanning Microscopy

An electron-beam tester was used to determine the depth profile of the internal potential distribution in an a-Si:H solar cell and hence the internal electric field profile. The a-Si:H solar cells were prepared for the measurements with the electron-beam tester by low-energy chemical plasma beam etching through a plasma-resistant mask structured by electron-beam lithography. In contrast to an earlier work, the solar cells were in situ illuminated and the electric field profiles were determined for new, degraded and in situ annealed solar cells at various cell temperatures. The measuring results demonstrate that the electron-beam testing technique in combination with a …

Comparative Scanning, Transmission And Atomic Force Microscopy Of The Microtubular Cytoskeleton In Fenestrated Liver Endothelial Cells, Filip Braet, Ronald De Zanger, Wouter Kalle, Anton Raap, Hans Tanke, Eddie Wisse

Scanning Microscopy

Endothelial fenestrae control the exchange of fluids, solutes and particles between the sinusoidal lumen and the microvillous surface of the parenchymal cells. Fenestrae have a critical dimension in the order of 150-200 nm, making it necessary to use microscopes with a resolution better than the light microscope. Comparative whole-mount preparations of isolated, purified and cultured rat liver sinusoidal endothelial cells (LEC) were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Examination of detergent-extracted LEC by SEM and TEM shows an integral cytoskeleton: sieve plates are delineated by a sieve plate-associated cytoskeleton ring and …

Characterizing The Outlines Of Degraded Fine-Particles By Fractal Dimension, Andrew Hunt, David L. Johnson

Scanning Microscopy

Fractal dimension has been used extensively as a descriptor of the rugged outlines of fine-particles. Potentially, it may be a useful parameter for characterizing the outlines of fine-particles which have been subjected to some form of chemical degradation. Here, fractal dimension values have been computed for the outlines of microscopic lead fine-particles both before and after weak hydrochloric acid dissolution experiments. Values obtained for the post-dissolution rugged profiles were greater than those of the pristine fracture grains which had a Euclidean form. The profiles of the degraded fine-particles could be characterized by a single fractal dimension value, or they exhibited …

Recognition And Phagocytosis Of Apoptotic Cells, Luciana Dini, Maria Teresa Ruzittu, Laura Falasca

Scanning Microscopy

Physiological elimination of unwanted cells within the organism occurs via cell death by apoptosis and phagocytosis of these cells represents a key event in the apoptotic process. Macrophages, which are the dedicated phagocytes, and other occasionally phagocytic cells ingest the apoptotic cells while they are still intact, thus preventing the leakage of potentially harmful materials from the dying cells. Although evidence has been presented that the elimination of apoptotic bodies from the tissue operates by means of specific recognition systems, the molecular mechanisms by which an apoptotic cell is recognized are poorly understood. Recent data indicate that phagocyte recognition of …

Scanning Electron Microscopic Study Of The Postnatal Development Of The Rabbit Cochlea, With An Emphasis On Innervation, Hirofumi Morita, Tomoyuki Hoshino, Kunihiro Mizuta, Satoshi Iwasaki

Scanning Microscopy

The development of nerve fiber arrangements of the organ of Corti was studied in rabbits 1, 3, 5, 7 and 12-days-old using thick sections from celloidin-embedded cochleas which were examined under a scanning electron microscope. The arrangements of nerve fibers varied with developmental age. The tunnel spiral bundle was thick and loosely collected in the immature cochlea. The outer spiral fibers were recognized even in the narrow space of Nuel in the one-day-old cochlea. As Nuel's space is extending, the fibers course along the medial side of Deiters' cells. The arrangement of the outer spiral fibers was irregular and sparse …

Volume Determination Of Human Metaphase Chromosomes By Scanning Force Microscopy, Wolfgang Fritzsche, Eric Henderson

Scanning Microscopy

The scanning force microscope (SFM) yields the topography of the investigated surface. A procedure was developed which starts from this three-dimensional information to estimate the volume of a biological specimen. The volume of spread human metaphase chromosomes was determined in air and rehydrated in aqueous buffer. A difference of the determined volume of a air-dried metaphase chromosome set was found compared to values from electron microscopic investigations, and could be correlated with differences in the hydration state of the chromosomes. SFM-based relative volumes of air-dried chromosomes resembles literature data regarding volume range and distribution. Possible application of SFM-based relative volume …

The Phase Effect In Electronic Stopping: A Survey Of The Contributing Physical Processes, P. Bauer, E. Steinbauer, F. Kastner

Scanning Microscopy

The phase effect in electronic stopping deals with the question whether the energy loss of an ion due to the interaction with electrons depends on the state of aggregation of the target. It is commonly accepted that charge changing collisions of the projectile and changes in the electronic states of the target contribute to the phase effect In addition, the energy loss measurements might possibly be influenced by different impact parameter selection in the two experiments (solid and gas phase). Quantitative results of our calculations show that generally the impact parameter selection inherently present in a transmission experiment is quenched …

Evaluation Of The Surface Changes In Enamel And Dentin Due To Possibility Of Thermal Overheating Induced By Erbium:Yag Laser Radiation, Tat̂Jana Dostálová, Helena Jelíková, Otakar Krejsa, Karel Hamal

Scanning Microscopy

This study investigates the thermal danger of Erbium (Er):YAG laser ablation. Classical preparation techniques have many disadvantages caused by unfavorable changes of temperature, pressure, and by mechanical vibrations. The effect of mechanical vibrations and pressure is eliminated by use of laser ablation technique. The purpose of this study was to analyze the side effects resulting from thermal changes of enamel and dentin in extracted human teeth subjected to pulsed Er:YAG laser radiation using both wet and dry ablation methods.

The micrographs of the sections were checked and measured afterwards. The effect of the investigated laser irradiation on the origin of …

Spatial Dependence Of Electron-Hole Pair Creation In Ion-Solid And Electron-Solid Interactions, F. J. García De Abajo

Scanning Microscopy

The problem of electron excitation induced by interaction of charged particles with solids is investigated on theoretical grounds. The excitation probability is calculated both in homogeneous media and at surfaces. The surface wake potential, needed in the latter, is reviewed. The cases of transmission and aloof geometries are considered separately. Surface plasmons are shown to play a crucial role in the latter. An application to coincidence scanning transmission electron microscopy (STEM) experiments is also discussed. Finally, a spatial representation of the excitation probability is presented.

Insights, Winter, 1995, Utah State University

Discovery Magazine

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

Insights, Fall, 1995, Utah State University

Discovery Magazine

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

Sexual Selection, Physical Attractiveness, And Facial Neoteny: Cross-Cultural Evidence And Implications [And Comments And Reply], Doug Jones, C. Loring Brace, William Jankowiak, Kevin N. Laland, Lisa E. Musselman, Judith H. Langlois, Lori A. Roggman, Daniel Pérusse, Barbara Schweder, Donald Symons

Human Development and Family Studies Faculty Publications

Physical attractiveness and its relation to the theory of sexual selection deserve renewed attention from cultural and biological anthropologists. This paper focuses on an anomaly associated with physical attractiveness-in our species, in contrast to many others, males seem to be more concerned than females with the attractiveness of potential sexual partners, perhaps because humans show far more age-related variance in female than in male fecundity. The resulting selection for male attraction to markers of female youth may lead incidentally to attraction to females displaying age-related cues in an exaggerated form. This paper reports cross-cultural evidence that males in five populations …

Critical Assessment Of The Operator-Splitting Technique In Solving The Advection-Dispersion-Reaction Equation: 1. First-Order Reaction, Jagath J. Kaluarachchi, Jahangir Morshed

Civil and Environmental Engineering Faculty Publications

Operator-splitting technique (OST) is a common mathematical approach used in the solution of the advection-dispersion-reaction equation (ADRE), especially in the presence of biological decay, where the scales of transport and biological decay are far apart. The OST introduces a time-lag between the advection-dispersion and reaction stages by splitting the ADRE causing a breakdown of the physics of the problem, thus limiting its applicability. In this work, the applicability of the operator splitting technique is studied in parts. This first manuscript addresses the critical limitations of the operator-splitting technique as related to first-order decay, and the second manuscript extends the work …

Inter-Alpha-Inhibitor: A Protein Family Involved In The Inhibition Of Calcium Oxalate Crystallization, Fouad Atmani, Jacques Mizon, Saeed R. Khan

Scanning Microscopy

Inter-α-inhibitor (IαI) is a serine protease inhibitor present in human plasma. It has a molecular weight of about 220 kDa which encompasses 3 chains including two heavy chains and one light chain. The light chain, known as bikunin, is responsible for the antitryptic activity of IαI in the inhibition of various enzymes, such as trypsin and chymotrypsin. Under physiologic or certain pathologic circumstances, several macromolecules related to IαI appear in plasma and urine. However, the physiologic role of IαI remains unclear. As far as urolithiasis is concerned, two urinary macromolecules related to IαI have been isolated and shown to be …

Quantitative Imaging In Electron And Confocal Microscopies For Applications In Biology, N. Bonnet, L. Lucas, D. Ploton

Scanning Microscopy

Among the large number of topics related to the quantification of images in electron and confocal microscopies for applications in biology, we selected four subjects that we consider to be representative of some recent tendencies. The first is the quantification of three-dimensional data sets recorded routinely in scanning confocal microscopy. The second is the quantification of the textural and fractal appearance of images. The two other topics are related to image series, which are more and more often provided by imaging instruments. The first kind of series concerns electron energy-filtered images. We show that the parametric (modelling) approach can be …

In Vivo Metal Substitutions In Metal Sequestering Subcellular Compartments: X-Ray Mapping In Cryosections, A. J. Morgan, C. Winters, A. Yarwood, N. Wilkinson

Scanning Microscopy

Qualitative digital X-ray mapping techniques were employed to determine the distributions of essential and non-essential elements in three invertebrate "models": (1) Pb, Zn, Cd, Cu, Fe in thin cryosections of the hepatopancreas of the terrestrial isopod, Oniscus asellus; (2) Pb, Zn, Cd, Ca in thin cryosections of the chloragogenous tissue of the earthworm, Lumbricus rubellus; and (3) As in air-dried smears and thin cryosections of chloragogen in L. rubellus. Four general conclusions were drawn from the results of these studies: (a) non-essential elements can accumulate, distribute and be compartmentalized because they, or the organo-complexes that they form, …

Mgo·1.5al2o3 Spinel Grain Growth And Microstructure Characterization By Scanning Electron Microscopy And Digital Image Analysis, G. Bonifazi, E. Proverbio

Scanning Microscopy

The microstructure of sintered polycrystalline MgO·1.5Al₂O₃ ceramic is strongly affected by the sintering conditions due to the precipitation of α-alumina at a temperature lower than about 1400°C. Consequently, the mechanical properties, depending on grain size distribution, are greatly influenced. Three different microstructures were obtained by a two step sintering process adopting an intermediate sintering temperature of 1050°C, 1100°C and 1300°C respectively, and a final sintering temperature of 1500°C. Comparable samples obtained directly by firing at 1500°C were used. Digital image analysis (DIA) carried out on scanning electron microscope (SEM) images was performed in order to better describe …

Target Geometry Dependence Of Electron Energy Loss Spectra In Scanning Transmission Electron Microscopy (Stem), A. Rivacoba, J. Aizpurura, N. Zabala

Scanning Microscopy

In the frame of the Self-Energy formalism, we study the interaction between STEM electrons and small particles in the range of the valence electron excitations. We first calculate the energy loss probability for an isolated sphere and study the loss spectrum dependence on the size of the particle and on the relative impact parameter. Then we analyze the loss spectra in more realistic situations: (a) the effect of the coupling between the particle and supporting surface is studied in a simple geometrical model; and (b) we analyze the dependence of the losses on the geometrical shape of the target by …

X-Ray Standing Wave Studies Of Ad-Dimers On Si(001), Y. Qian, P. F. Lyman, M. J. Bedzyk

Scanning Microscopy

X-ray standing waves generated by dynamical Bragg diffraction were used as an element-specific structural probe for investigating Ga and Sb adsorption on Si(001). Using the (004) and (022) reflections, we precisely measured Ga and Sb ad-dimer bond lengths and ad-dimer heights above the bulk-extrapolated Si(001) surface. The room temperature [001] thermal vibration amplitudes of Ga and Sb adatoms on Si(00l) were also directly determined by combining the fundamental (004) and high-order harmonic (008) X-ray standing wave measurements. These high-resolution measurements reveal important quantitative structural information regarding the dimerized surface structures, and provide a stringent test for structural models proposed by …

Enamel Prism Morphology In Molar Teeth Of Small Eutherian Mammals, Elizabeth R. Dumont

Scanning Microscopy

Data summarizing enamel prism shape, sire and spacing are reported for the molar enamel of 55 species of small eutherian mammals including primates, bats, tree shrews, flying lemurs, insectivorans and representatives of a variety of fossil families. Confocal photomicrographs reveal that the subsurface enamel of most species is characterized by arc-shaped prisms. The lack of a clear distinction between pattern 2 and pattern 3 prism configurations within single specimens suggests that the broad category "arc-shaped prisms" is the most appropriate descriptive grouping for these species. Of the total sample, three species exhibit only circular prisms while no evidence of prismatic …