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Measurement Of Factors Affecting Crop Production, Terrence F. Glover

Economic Research Institute Study Papers

This paper is concerned with characterizing the effect that environmental and induced factors have on crop yields. In this sense, a framework is outlined which can be used to estimate the characteristics of the probability distribution function (pdf) of crop yields which may not be normal or log-normal as usually is assumed. The paper is methodological in nature, but several pieces of empirical work are being done under the sponsorship of the Utah Experiment Station, particularly modeling alfalfa yield response to changes in pest control and environmental factors which influence alfalfa yields. The methodological framework developed here is in the …

Big Bend National Park Biosphere Reserve: A History Of Scientific Study - Volume I: A Narrative Description Of Scientific Study, John A. Bissonette, John W. Ault Iii

Wildland Resources Faculty Publications

In 1971 the United Nations Educational, Scientific, and Cultural Organization (UNESCO) created the Man and the Biosphere (MAB) Program for the purpose of promoting rational use of the earth's resources. Formal involvement by the U.S. began in 1974. By 1976, 28 biosphere reserves had been selected in the U.S., including Big Bend National Park (BBNP) (Fig. 1). The purpose of this 2-volume report was to provide an interdisciplinary reference volume of literature citations for BBNP and the surrounding Chihuahuan Desert, and to provide a synopsis of research completed at BBNP.

Survival And Growth Of Adult Human Oligodendrocytes In Culture: Scanning Electron Microscopy, Seung U. Kim, Kookmin M. Kim, Giuseppe Moretto, Doo H. Shin

Scanning Electron Microscopy

The oligodendrocytes in culture serve as an important model for the study of demyelination diseases. We have previously originated a method of isolating human oligodendrocytes. In order to establish their three dimensional morphology, scanning electron microscopy of the cultured oligodendrocytes was performed.

The oligodendrocytes bulk isolated from adult human brain were maintained in culture for more than 2 months. At the various periods in culture, the cells were studied by scanning electron microscopy and immunofluorescence staining using marker antibodies for the identification of oligodendrocytes. The three dimensional organization and the surface morphology of the cultured oligodendrocytes were investigated. They displayed …

The Growth Of Fetal Human Sensory Ganglion Neurons In Culture: A Scanning Electron Microscopic Study, Seung U. Kim, Kookmin M. Kim, Giuseppe Moretto, James H. Kim

Scanning Electron Microscopy

Sensory neurons of 8-week human fetal dorsal root ganglia were dissociated into single cells by trypsinization and cultured on coverslips for 4 months, in either serum-containing or serum-free chemically defined media. At different times the cultures were fixed and prepared for scanning electron microscopy. Fetal sensory neurons in culture regenerated axons within 24 hours which were characterized by axonal growth cones at their tips and the neuronal perikarya assumed spherical or a bonnet-like morphology.

The Interphotoreceptor Matrix And The Interphotoreceptor Space Of The Vertebrate Retina, M. H. Bernstein

Scanning Electron Microscopy

The interphotoreceptor space (IPS) of the vertebrate retina is the adult corollary of the lumen within the embryonic optic vesicle. The inner limit of the IPS is formed by the intercellular junctions of Muller cells and photoreceptors forming the external limiting membrane (ELM). The apical surface of the retinal pigment epithelium (RPE) is the outer limit of the IPS. Most of the volume of the IPS is occupied by the inner and outer segments of the photoreceptors, with the microvillous processes of the RPE, and the small microvilli of the Muller cells filling lesser portions. SEM of samples fixed in …

Theoretical Considerations On Surface Extended X-Ray Absorption Fine Structure (Exafs), Claudine Noguera

Scanning Electron Microscopy

We have investigated the following theoretical points relevant to surface EXAFS: proportionality of the signal to the absorption cross section, analysis of the oscillations with the simple EXAFS formula, accuracy in the determination of distances and coordination numbers, transferability of phase shifts and amplitude factors. We describe some of the most used techniques to record the Surface Extended X-Ray Absorption Fine Structure (SEXAFS) oscillations, both the photon induced techniques and the electron induced ones, such as the Auger effect, the total or partial yield, the ion desorption technique, the appearance potential spectroscopy and surface reflection electron loss spectroscopy; and in …

Limits Of Quantitative Microanalysis Using Secondary Ion Mass Spectrometry, Peter Williams

Scanning Electron Microscopy

The limitations on secondary ion micro-analytical performance imposed by ionization probabilities, mass spectrometer transmission, requirements for standards and sputtering artifacts have been investigated. The sensitivity of a modern magnetic mass spectrometer for sputtered B⁺ from oxidized Si is ~ 10^-2 ions detected/atom sputtered. For this sensitivity, it is shown that ion microscopy of a part-per-million impurity is limited in lateral resolution to ~ 1 μm. For a 1% impurity, lateral resolution of ~ 30 nm is achievable. Depth profile analysis at the ppm level requires sample areas ~ 10 μm². Isotope abundance determinations in volumes ~ …

Fly Ash From Full Scale Trona Injection Studies, Raymond T. Greer, Da-Tong Zhang

Scanning Electron Microscopy

Sodium sesquicarbonate (NaHCO₃-Na2CO₃-2H₂O) and the mineral trona (NaHCO₃-Na2CO₃-2H₂O) have been utilized as effective dry sorbents for SO₂ in flue gas during fossil fuel plant full-scale injection studies conducted at the Cameo Station, Unit 1, of Public Service Company of Colorado near Grand Junction, CO. Microstructural and microchemical characterization studies of fly ash samples from these studies identify decomposition features for these carbonates that relate to the development of satisfactory reaction surface areas for combination with SO₂ from flue gas. The major features are non-sulfur bearing microspheres …

Freeze-Drying And Related Preparation Techniques For Biological Microprobe Analysis, Romuald Wróblewski, Joanna Wróblewski, Matti Anniko, Lars Edström

Scanning Electron Microscopy

An X-ray microanalytical and morphological investigation has been carried out on rapidly frozen, freeze-dried or freeze-substituted tissues. A comparison was made between different embedding and polymerisation procedures following freeze-substitution and freeze-drying. The investigation also included an analysis of specimens infiltrated, embedded and polymerised by ultraviolet irradiation at low temperatures with Lowicryl HM20. The morphological preservation of Lowicryl embedded tissue was adequate for the identification of different cell structures like nuclei, mitochondria, lysosomes and different types of endoplasmic reticulum. X-ray microanalytical investigation of low temperature embedded material displayed an elemental composition of cells and organelles similar to that found in freeze-dried …

Recent Developments In Electrical Microcharacterization Using The Charge Collection Mode Of The Scanning Electron Microscope, D. B. Holt, M. Lesniak

Scanning Electron Microscopy

There are six distinguishable types of charge collection (CC) signal. Consequently specially designed CC detection systems are needed to obtain e.g. true EBIC and EBIV measurements and make quantitative electrical microcharacterization possible. EBIC and EBIV can arise from fields due to barriers such as p-n junctions or due to changes in doping e.g. p to p+. Materials, defect and device parameters are calculable from these signals. Hot-cold stages are important for temperature dependence studies of contrast, for improving signal to noise ratios and reducing leakage currents. Image processing and pattern recognition methods are vital for rapidly locating and evaluating the …

Applications Of Scanning Electron Microscopy And X-Ray Microanalysis In Inner Ear Pathology, M. Anniko, D. J. Lim, A. Sobin, R. Wróblewski

Scanning Electron Microscopy

Surface pathology of inner ear structures so far described in detail concern cochlear and vestibular hair cells and the stria vascularis. In man, surgical intervention into the inner ear is very uncommon and when performed is in general with the primary objective of destroying the diseased peripheral end organs. The vast majority of inner ear tissue available for use with scanning electron microscopy (SEM) is therefore obtained from animals.

The present paper reviews the progression of surface pathology caused by aminoglycoside antibiotics, acoustic overstimulation and in a guinea pig strain with genetic inner ear disease. The primary site of onset …

Cell Movement And Contraction In Somite Development, Ellen A. G. Chernoff

Scanning Electron Microscopy

During somite formation the segmental plate mesoderm, lying on either side of the axial organs, reorganizes into roughly spherical pairs of epithelial structures. This segmentation process includes changes in cell shape and position, cell-cell and cell-substratum adhesive properties and accumulation of extracellular matrix material which proceed down the anterior-posterior axis. Later in somite development the sclerotome region "disperses", migrating around the spinal cord where it produces the cartilage model of the vertebral column. Experimental manipulation of segmentation and sclerotome dispersal with drugs affecting microfilaments, microtubules and calcium-dependent contraction suggest that cells migrate into position, elongate, and undergo apical contraction as …

Ultrastructural Studies Of Crystal-Organic Matrix Relations In Renal Stones, P. -T. Cheng, A. D. Reid, K. P. H. Pritzker

Scanning Electron Microscopy

Biochemically the organic matrix of kidney stones contains mucoproteins, mucopolysaccharides, inorganic material and bound water. Morphologically, the organic matrix exists as either amorphous or fibrous forms. We have attempted to critically evaluate results from analytical and morphological studies on stone matrices using light microscopy, histochemistry, x-ray diffraction, scanning electron microscopy, x-ray energy dispersive spectrometry, transmission electron microscopy and selected area electron diffraction.

On the surface of calcium oxalate stones, there are usually large masses of randomly deposited calcium oxalate crystals each coated with organic matrix. Transmission electron microscopy shows these large surface crystals are composed of rows of smaller crystallites …

Electron Beam Induced Damage On Passivated Metal Oxide Semiconductor Devices, S. Görlich, E. Kubalek

Scanning Electron Microscopy

Electron beam testing of integrated circuits (IC) is currently based on the electron beam induced conductivity in insulators to short the passivation layer and to enable a voltage measurement at covered conductor tracks. However, applying this technique to passivated MOS devices causes severe radiation damage, which was at first explained by primary electrons penetrating into the deep-lying gate oxide. Nondestructive electron beam testing was expected by using low electron energies that do not allow the primary electrons to reach into the gate oxide.

Therefore here the influence of nonpenetrating electron irradiation on the characteristics of passivated NMOS transistors has been …

Food Microstructure

Food Structure

No abstract provided.

Microstructure Of Meat Emulsions In Relation To Fat Stabilization, Chong M. Lee

Food Structure

No abstract provided.

Ultrastructural Studies On The Cultivation Processes And Growth And Development Of The Cultivated Mushroom Agaricus Bisporus, D. A. Wood, G. D. Craig, P. T. Atkey, R. J. Newsam, K. Gull

Food Structure

Scanning electron microscopy (SEM) , transmission electron microscopy and light microscopy have been used to study various processes in the cultivation of the edible mushroom Agaricus bisporus . Mushrooms are cultured on composted wheat straw. The microbial degradation processes during composting have been visualised by TEM and SEM and correlated with microbiological studies . Various modes of attack by the microorganisms on the plant cell walls can be seen. Most rapid degradation occurred on the cuticle and phloem and spread to other cell types. Microbial attack was found to be nonuniform between tissue types and individual cells. The mycelium of …

Cryoultramicrotomy And Electron Microanalysis Of Isolated Bovine Adrenal Chromaffin Cells, Richard L. Ornberg

Scanning Electron Microscopy

Instrumentation and techniques have been developed for the cryoultramicrotomy of isolated bovine adrenal chromaffin cells frozen with a liquid helium cooled copper block method. X-ray microanalysis and electron energy loss spectroscopy were used to measure both light and heavy element content of the adrenal storage granule, the chromaffin granule. Ultrathin freeze-dried cryosections usually have a fine compression which in cellular structure compresses the cytoplasm between organelles. Nuclei, chromaffin granules, and vacuoles are relatively free of compression. The mechanism for this distortion is not known al though static charge induced sticking to the knife may be the most probable cause.

The …

In Vivo Light Microscopy Of Organs, Robert S. Mccuskey

Scanning Electron Microscopy

High resolution, brightfield and fluorescence, light microscopic methods have been developed for examining living organs in situ. The methods permit study of the rate, duration, magnitude and direction of dynamic histologic, pathologic, physiologic and pharmacologic events. In addition, morphometric analyses of such living preparations can provide basic information needed to evaluate alterations induced by fixation and processing of these organs for electron microscopy. Most organs are amenable to such investigations. In anesthetized animals, the selected organ is trans-and/or epi-illuminated with selected wavelengths of monochromatic light, imaged with water immersion objectives and the resulting monochromatic optical images televised using silicon …

Physics Of The Preparation And Observation Of Specimens That Involve Cryoprocedures, E. Kellenberger, E. Carlemalm, W. Villiger

Scanning Electron Microscopy

With this introductory chapter we attempt a synthesis of old and new knowledge of the physical principles that govern cryomethods. Interface phenomena determine the increase or decrease of the number of particles observed in frozen-hydrated suspensions because they occupy the air-liquid interface according to their specific balance of hydrophobic versus hydrophilic properties. Biological macromolecules are surrounded by organised water, the hydration shell, that prevents them from sticking to each other. Partial or complete removal of these hydration shells by freeze-drying or freeze-substitution leads to collapses or aggregations. The solvent-induced aggregation is usually decreased by prior cross-linking with adequate chemical fixatives. …

On The Application And Possibilities Of In Vivo Microscopy In Liver Research, E. Wisse, R. S. Mccuskey

Scanning Electron Microscopy

In vivo microscopy (IVM) provides a valuable method for studying the histophysiology of the living liver. The method allows observation of living cells in the intact organ of an anesthetized animal with an undisturbed microcirculation, at a magnification and a resolution comparable to normal light microscopy of sectioned material. Due to the absence of preparative procedures, the image differs substantially from histological sections, but it has the advantage of providing us with a reference preparation free of artifacts. In the case of the liver, we have the opportunity to observe directly such details as bile capillaries, intracellular fat droplets, lysosomes, …

Soil Water And Temperature In Harvested And Nonharvested Pinyon-Juniper Stands, United States Department Of Agriculture, Forest Service

Forestry

Tree harvesting increased soil water content, but the effect diminished over 4 years. The mean increase in soil water content was 2 to 4 percent the first year following harvest and 0 to 3 percent after 4 years. Although tree harvesting released soil water previously used by tree species, other biotic and abiotic demands increased. We speculate postharvest increases in wind and solar energy at the ground surface and increased understory transpiration in part explain the decline in soil water content differences between harvested and nonharvested plots over time.

The Size Distribution Of Bovine Casein Micelles: A Review, C. Holt

Food Structure

This review considers the average size and size distribution of bovine casein micelles as measured by electron microscopy, light scattering and controlled pore glass chromatography, and the origin and biological function of the size distribution.

Recent work by electron microscopy has given average sizes in reasonable agreement with measurements on the same milk sample by light scattering . It is suggested that natural variations in averaqe micelle size and overestimation of micelle radii by light scattering methods as well as deficiencies in electron microscopical methodology were responsible for past discrepancies.

Electron microscopy and controlled pore glass chromatography provide evidence that …

Food Microstructure

Food Structure

No abstract provided.

Response Of Grass Species To Tree Harvesting In Singleleaf Pinyon-Utah Juniper Stands, United States Department Of Agriculture, Forest Service

Forestry

Cover, yield, and nutrient concentrations of grasses were sampled on tree-harvested and nonharvested plots on north, west, and south aspects of a singleleaf pinyon (Pinus monophylla)-Utah juniper (Juniperus osteosperma) stand. Grass cover increased rapidly the first 2 years following tree harvest, but the rate of increase declined over the next 2 years. Grass yield varied among aspects and soil microsites on tree-harvested plots but not on the nonharvested plots where tree competition masked aspect and microsite effects. All grass species had greater yield and greater percentage nitrogen and phosphorus on harvested than on nonharvested plots. Low digestibility of some species …

Ultrastructural Ultilization Of Plants By Herbivores, L. H. Harbers

Food Structure

Study of the patterns of ruminal digestion of forages enhances the nutritional knowledge of how specific plant tissues are digested and adds its own dimension by characterizing the specific cells and the complex interactions of ruminal microflora with those tissues. A common pattern of digestibility exists for mono- and dicotyledon leaves: mesophyll and phloem are degraded readily, and sclerenchyma slowly, whereas cuticle and the remaining vascular tissues are rarely utilized . Digestion of stems is limited to parenchymal tissues in monocotyledons and to cortex and parenchyma in dicotyledons. Epidermal silica and cuticle are undigestible and restrict microbial entrance. Calcium oxalate …

Glutaraldehyde Fixation Chemistry A Scheme For Rapid Crosslinking And Evidence For Rapid Oxygen Consumption, Timothy J. A. Johnson

Scanning Electron Microscopy

The chemical literature suggests that pyridine derivatives are the major reaction products of amine-aldehyde reactions. A scheme is proposed for pyridine synthesis which is derived from a classic synthesis of pyridines from one amine molecule and 3 aldehyde molecules. The pyridine polymers are considered as a major class of cross-links in glutaraldehyde fixed cells. This scheme for pyridine synthesis accounts for the following observations of amine-glutaraldehyde react ions: 1) large quantities of acid are rapidly produced, 2) oxygen uptake occurs at a high rate, 3) a variety of products distinguished by molecular size are rapidly and irreversibly synthesized, and 4) …

Scanning Electron Microscopic Study Of Rockfish Preserved At Either Ambient Temperature Or By Isothermal Freeze-Fixation, L. E. Lampila, V. Mohr, D. S. Reid

Food Structure

Fresh rockfish (Bocaccio, Sebastus paucispinis) fillets were blast frozen and stored at either -5 °C or -20 °C for 60 days . At defined sampling intervals, speci mens were removed and chemically fixed at either ambient temperature or isothermally, at the respective storage temperatures (-5 °C or -20°C) . The results indicated that isothermally freeze - fixed specimens showed a degree of crushing and/or distortion of the muscle fiber, the deposition of presumed ice crystals in the cell membrane, the multi-dimensionality of connective tissue and the preservation of fine detail . In specimens fixed at ambient temperatures , structura l …

Changes In Typical Organelles In Developing Cotyledons Of Soybean, K. Saio, K. Kondo, T. Sugimoto

Food Structure

Soybean cotyledonary cells harvested every 5-10 days at 15 to 60 days after flowering (OAF), were investigated by means of light and transmission electron microscopy. In the early developing stages (15-20 OAF) most of the cells were occupied by large, centrally located vacuoles while the cytoplasm was restricted to a thin layer against the cell wall and contained numerous ribosomes, mitochondria, plastids, small amounts of endoplasmic reticulum (ER) and minute lipid bodies. At about 25 OAF, spherical organelles which contained protein, lipid and sugar (PLS bodies), appeared and then increased in number and in size. Vacuoles had protein deposits lining …

Tandem Scanning Reflected Light Microscopy, Mojmir Petran, Milan Hadravsky, Alan Boyde, Martin Mueller

Scanning Electron Microscopy

Most attempts at optical microscopy of bulk living objects have failed because of reflections from optical components and the object surface, and overlapping of unsharp out-of-focus images with the one (weak) sharp in-focus image. The optical signal in the image plane thus consists of a strong d.c. component, a weak noise and a still weaker signal. Most of the first two components can be suppressed by scanning in concordance with both the illuminating and the image-forming rays. In the first scan the focussed-on-object plane is illuminated only in several very fine discrete spots. In the second scan only that light …