Digital Commons Network^™

Displays: Market And Technologies, Steve Blazo

Scanning Electron Microscopy

Displays provide the essential human interface to virtually all electronics instrumentation. The market is large with new applications appearing every year; sometimes with profound impact. Digital watches with liquid crystal displays appeared in the early 1970s and have virtually wiped out the mechanical timepiece industry. Personal computers with cathode ray tube (CRT) displays are proliferating with diverse applications in the industry and in the home. Work stations with high-resolution color displays are changing the way architects, draftsmen, and IC designers perform their job. The CRT is the dominant technology in today's market, and will, no doubt, continue to be for …

Field Emission Source Optics, L. W. Swanson

Scanning Electron Microscopy

The use of field emission processes as a means of generating high brightness sources of both electrons and ions is becoming of increasing practical use in electron/ion optical systems. A review is given of the source optics and emission characteristics of a zirconium oxide coated, <100> oriented, tungsten (Zr0/W(l00)), thermal field emitter electron (TFE) source and a liquid metal ion source (LMIS). The primary interest at present is the use of these high field sources in microprobe focusing columns where beam sizes of < 0.5 µm and target current densities of ~ 1 to 10 A/cm² (in the case of a LMIS) and 10² to 10⁴ A/cm² (in the case …

Electron Beam Deflection Without Off-Axis Aberrations, H. C. Pfeiffer, M. A. Sturans

Scanning Electron Microscopy

A novel focusing/deflection system for high accuracy, high throughput E-beam lithography, denoted as Variable Axis Immersion Lens (VAIL), has been successfully demonstrated. The main attributes of this system include: l) Perpendicular landing at all points of a deflection field > (10 x 10 mm), 2) Elimination of transverse chromatic aberration, 3) High resolution ( < 0.2μm edge slope) over the entire deflection field, 4) Elimination of eddy current effects in the target area, and 5) Total magnetic shielding of the target from external fields.

Synthesis Of Electron Lenses, M. Szilagyi

Scanning Electron Microscopy

This paper is a review of different approaches to one of the most ambitious goals of Electron and Ion Optics: to produce elements and systems with prescribed first-order properties and minimal aberrations. Synthesis of such elements is usually done in two steps: the first is a search for a field distribution with the given properties and the second is the reconstruction of electrodes (pole pieces) that would produce this field distribution. The first problem can be solved by the use of different techniques: Calculus of Variations, Dynamic Programming or Function Minimization. The second one is more complicated and requires a …

Extracellular Enzyme Production By Rhizopus And Mucor Species On Solid Media, D Thompson, Broderick Eribo

Department of Biology Faculty Publications

Solid media were employed to determine the presence and absence of extracellular enzyme production by two genera of fruit-rot fungi, Rhizopus and Mucor. The results of this investigation revealed that phosphatase was released into the cultural medium by all the fungi examined; however, only R. oryzae, R. tritici, M. mucedo, and M. piriformis showed the possibility of being high producers of the enzyme. Protease, urease, ribonuclease, pectate lyase, and polygalacturonase, at varying levels of activity, were detected, in the majority of the fungi, in the cultural medium.

An Ultrastructural Study Of Transmitting Tissue Development In The Pistil Of Lilium Leucanthum, Stanley R. Gawlik

Biology Faculty/Staff Publications

A study of developing transmitting tissue of Lilium Leucanthum pistils was undertaken in order to correlate structure with function. Lining the stylar canal are stigmatoid cells which contain a secretory zone consisting of a labyrinth of wall ingrowths characteristic of transfer cells. The functional feature of the labyrinth is a high surface-to-volume ration that facilitates an intensive transmembrane flux of solutes. Stigmatoid cells in various stages of development and maturation have been investigated with the aid of electron and light optics in conjunction with cytochemical techniques. During the development of the secretory zone, vesicles, formed by hypersecretory dictyosomes, fuse with …

Herbivory Effects On Thalassia Testudinum Leaf Growth And Nitrogen Content, J. C. Zieman, R. L. Iverson, John C. Ogden

Integrative Biology Faculty and Staff Publications

The pattern of turtle grazing on Thalassia testudinum in St. Croix seagrass beds begins with the establishment of a grazing plot by initial removal of leaf blades, followed by repeated grazing of several centimeter-long leaf blades within a maintained grazing area. Plants within the grazed area exhibit increased specific growth rate as a consequence of increased light flux to unepiphytized leaf bases. Leaf width is reduced in the grazed area as a consequence of grazing stress. The leaf bases contain a higher proportion of nitrogen and a lower lignin content than the leaf tips, in addition to lacking epiphytes. Our …

A Biosystematic Study Of The Fern Genus Lygodium In Eastern North America, Violet M. Brown

Retrospective Theses and Dissertations

The mainly tropical genus Lygodium differs from other ferns in that the fronds are indeterminate and are vine-like. A single species, L. palmatum is native in temperate North America. The temperate Asian L. japonicum is naturalized throughout much of the southeastern United States. About twenty years ago, L. microphyllum was introduced into South Florida and is now naturalized in several counties. The present study documents differences among spores and their generation, development of sporophytes from the fertilized egg, and in flavonoid chemistry. Hybridization experiments showed a strong possibility for cross fertility between species. Experiments with prothallial development and differentiation revealed …

A Study Of Cladonia Cryptochlorophaea And Morphologically Similar Species In Illinois, Indiana, And Wisconsin, Scott S. Wilcer

Masters Theses

Collections of Cladonias with cup-shaped podetia were made in Illinois, Indiana, and Wisconsin in order to determine the distribution of an atranorin-containing variant of Cladonia cryptochlorophaea, which was discovered in 1982 in Coles County, Illinois by Cheryl Cunningham. A second objective was a distributional study of the Cladonias having cup-shaped podetia in the same three state area.

A total of 591 specimens were collected from the three states. The collection areas for Illinois were: Jackson Hollow in Pope County, Giant City State Park and Touch of Nature Interpretive Center in Jackson and Williamson Counties, Starved Rock State Park in …

Vegetative Key To Grasses Of The Sand Hills Region Of Nebraska, David M. Sutherland

Biology Faculty Publications

All illustrated key is provided that will facilitate identification of grasses in the vegetative condition in the Sand Hills region of Nebraska. The key separates 97 species, varieties, and species groups and discusses or partially separates 14 additional taxa. It emphasizes characteristics that may be observed in the field with a hand lens and is illustrated with 109 camera lucida drawings.

Comparison Of Three Methods For Sampling Fishes And Macroinvertebrates In A Vegetated Wetland, B. J. Freeman, H. S. Greening, J. Douglas Oliver

Faculty Publications and Presentations

Three methods of sampling fishes, two seining methods and a drop trap method, were evaluated in heavily vegetated freshwater habitats. The portable drop trap method, which utilized a 1 x 1 m-sq. trap, collected significantly more macroinvertebrates and fish per unit area than did the seining methods. The meter square drop trap offered the additional advantages of a greater number of animals per unit effort and an integrated sample of vegetation, macroinvertebrates and fish in a given area. A 90% (s.d.= 7.4%) recovery of tagged fishes released into the traps in different habitats showed the m2 drop trap to be …

Characteristics Of A Ca++ Atpase Enzyme In The Epidermis Of Molting Blue Crabs, Callinectes Sapidus, Joanne Elizabeth Lapetina

Master's Theses

Epidermal Ca⁺⁺-activated ATPase was investigated in relation to the molt cycle of the blue crab, Callinectes sapidus. Premolt and postmolt tissue samples demonstrated significant elevations in Ca⁺⁺-activated ATPase activity in comparison to intermolt tissue samples. These results support the suggestion that this enzyme may participate in demineralization of the old cuticle, as well as calcification of the new cuticle.

The enzyme is localized in the heavy particulate-nuclear fraction and is distinguished from mitochondrial Ca⁺⁺ ATPase found in other tissues by differences in sensitivity to mersalyl acid. 0 The enzyme is most active at 49 C …

The Effects Of Photoperiod And Melatonin Injections On The Reproductive System Of The Male Mongolian Gerbil (Meriones Unguiculatus), Luis Jose Cova Marchan

Master's Theses

This work was undertaken to study the effects of photoperiod and melatonin on fertility in male Mongolian gerbils (Meriones unguiculatus). Four groups of fifteen animals each, were placed in different photoperiods (ambient, ranging from 14L:10D to 11.3L:12.3D; 24L:10D; 14L:10D; and 1L:23D). After 35 days, three gerbils from each photoperiod condition were sacrificed and the testes, epididymides, seminal vesicles, prostate, kidneys, adrenals, thymus and hypophysis were weighed. The testes and epididymides were placed in Bouin's fixative and used for histological studies. Also, two males from each photoperiod condition were paired individually with a female. The remaining animals of each photoperiod condition …

Wood Anatomy And Relationships Of Neowawraea (Euphorbiaceae), Dörthe S. Brandt, W. John Hayden

Honors Theses

Wood anatomy of three specimens of Neowawraea phyllanthoides Rock, a rare and endangered member of Euphorbiaceae endemic to the Hawaiian Islands, is described and compared with woods of other genera of subfamily Phyllanthoideae. Neowawraeahas often been associated or synonymized with Drypetes Vahl. Wood of Neowawraea is diffuse porous, perforation plates are simple, imperforate tracheary elements are thin-walled septate fiber-tracheids, rays are heterocellular and crystalliferous, and axial xylem parenchyma is restricted to a few scanty paratracheal and terminal cells. In several respects these results differ from earlier published descriptions of the wood of this taxon; these earlier descriptions are shown …

Security Of Infantile Attachment As Assessed In The Strange Situation: Its Study And Biological Intrepretation, Michael E. Lamb, Ross A. Thompson, William P. Gardner, Eric Charnov, David Estes

Biology Faculty & Staff Publications

We study the Ainsworth 'Strange Situation' procedure to assess attachment between infant and parent, and intrepret individual variation in terms of modern human behavioral ecology ( sociobiology)

Why Are There Essential Amino Acids And Other Nutrients?, Eric Charnov

Biology Faculty & Staff Publications

No abstract provided.

Seasonal Shifts Of Photosynthesis In Portulacaria Afra (L.) Jacq., Lonnie J. Guralnick, Patricia A. Rorabaugh, Zac Hanscom

Arts & Sciences Faculty Publications

Portulacaria afra (L.) Jacq., a perennial facultative Crassulacean acid metabolism (CAM) species, was studied under natural photoperiods and temperatures in San Diego, California. The plants were irrigated every fourth day throughout the study period. Measurements of ¹⁴CO₂ uptake, stomatal resistance, and titratable acidity were made periodically from July 1981 through May 1982. P. afra maintained C₃ photosynthesis during the winter and the spring. Diurnal acid fluctuations were low and maximal ¹⁴CO₂ uptake occurred during the day. The day/night ratio of carbon uptake varied from 5 to 10 and indicated little nocturnal CO₂ uptake. CAM …

The Ontogeny And Functional Significance Of Luteinizing Hormone Releasing Hormone (Lhrh) Containing Centers Of The Brain Of The Freshwater Teleost, Xiphophorus Maculatus, Leslie R. Halpern-Sebold

Dissertations, Theses, and Capstone Projects

The use of cytometric, immunocytochemical and radioimmunological methods has allowed the investigation of the ontogeny and functional significance of LHRH containing centers in sibling platyfish (Xiphophorus maculatus) genetically determined to reach sexual maturity at different ages and in adult fish which were hypophysectomized and given replacement therapy with gonadotropin.

There is a sequential development of three immunoreactive (ir-) LHRH centers in the brain that is directly related to stage, not age of sexual maturation. The first region to contain ir-LHRH is the nucleus olfactoretinalis (NOR). Ir-LHRH then appears in the nucleus preopticus periventricularis (NPP), followed by the nucleus lateralis tuberis …

Inflorescence Architecture And Evolution In The Fagaceae, Robert B. Kaul, Ernst C. Abbe

School of Biological Sciences: Faculty Publications

First paragraph:

Inflorescence architecture is receiving increasing attention with respect to its role in the life of plants, but much remains to be learned of its effects on pollination and dispersal biology (see Wyatt, 1982). Little is known of the biology of fagaceous inflorescences or of their relationships with the growth or the reproductive patterns of the trees. Most studies (Abbe, 1974; Macdonald, 1979; Fey & Endress, 1983) have concentrated on the nature of the flower clusters (often called dichasia or partial inflorescences) and cupules. Hjelmqvist (1948) and Soepadmo (1972) briefly reviewed the variety of inflorescences in the Fagaceae. Čelakovský …

Las Vegas Wash Advanced Water Quality Study: Final Report, Richard A. Roline, James J. Sartoris, U.S. Bureau Of Reclamation

Publications (WR)

The purpose of the Las Vegas Wash Advanced Water Quality Study is to determine the existence, extent, and mechanisms of nutrient and toxin stripping in Las Vegas Wash under present conditions and under future conditions, both with and without construction of the proposed salinity control unit as described by the Bureau of Reclamation (USBR, 1982b). This study was performed for the Lower Colorado Region Division of Planning by personnel of the Environmental Sciences Section of the Division of Research and Laboratory Services, E&R Center, Denver, Colorado. Work on the study began in February 1983. The general approach adopted for this …

Factors Affecting Reproductive Success Of Bonytail Chubs And Razorback Suckers In Lake Mohave, Michael A. Bozek, Larry J. Paulson, James E. Deacon, U.S. Department Of Interior, Fish And Wildlife Service

Publications (WR)

Razorback suckers (Xyrauchen texanus) and bonytail chubs (Gila elegans) were once widespread throughout the Colorado River system. The ranges and populations of these native species and others have declined in the past 50 years. Bonytail chubs appear to be extremely rare and possibly nearing extinction in the Upper Colorado River Basin. The razorback sucker is widely distributed in the upper river but is considered rare throughout most of that range and is also rare in the Grand Canyon. Razorback suckers are abundant only in a few habitats in the upper river. They congregate and spawn over …

The Reproductive Biology Of Sternotherus Minor Minor (Reptilia: Testudines: Kinosternidae) From The Southern Part Of Its Range In Central Florida, Cory R. Etchberger

Retrospective Theses and Dissertations

Variation in chelonian reproductive patterns is well documented. Previous studies of loggerhead musk turtles (Sternotherus minor) reproduction have not attempted to control for variation in latitude, local population differences, and seasonal variation. The present study attempts to control for these variables by collecting turtles from one population for one reproductive season. The reproductive pattern of S. minor at the southern limit of its range (Central Florida) is compared to those of S. minor studied elsewhere. Both male and female musk turtles mature after five to six years and at approximately 60mm plastron length. No sexual dimorphism in overall body size …

The Effects Of Beach Restoration On Marine Turtles' Nesting In South Brevard County, Florida, Paul W. Raymond

Retrospective Theses and Dissertations

The south Brevard coast of Florida is a major nesting ground for the Atlantic loggerhead turtle (Caretta caretta). A beach restoration project was completed in the winter of 1980-81 at Indialantic and Melbourne Beach. A study was conducted to investigate the effects of beach restoration on marine turtle nesting during the summer months of 1981 and 1982. A 3.1 km restored beach study area and two control beach study areas, each 3.1 km in length and consisting of natural beach sands, were established. The entire study area (9.3 km) was monitored for nesting and non-nesting emergences (false crawls) and a …

The Isolation And Identification Of Flavonoids In Zygocactus, Jacqueline M. Wade

Retrospective Theses and Dissertations

No abstract provided.

Factors That Influence Plant Species Richness On Habitat Islands Of Sand Pine Scrub, Cindy B. Connery

Retrospective Theses and Dissertations

No abstract provided.

Leptodactylus Podicipinus (Cope, 1862) Y Leptodactylus Chaquensis Cei, 1959 (Anura, Leptodactylidae), En El Uruguay, Raúl Vaz-Ferreira, Rafael O. De Sá, Federico Achaval, Annelise Gebrau

Biology Faculty Publications

En base al estudio de las colecciones obtenidas principalmente en excursiones a la zona NO de Uruguay con motivo del relevamiento faunístico del área de Salto Grande, se avanzó considerablemente en el conocimiento de la distribución de Leptodactylus podicipinus (Cope, 1862) y Leptodactylus chaquensis (Cei, 1950), en nuestro país.

Se cita el material estudiado y las observaciones de campo realizadas; se dan los caracteres generales de ambas especies, se describen los hábitats, y se tratan las características de las vocalizaciones.

A Survey Of The Living Hermatypic Corals On The West Fore Reef Of Discovery Bay, Jamaica After The Occurence Of Hurricane Allen, James Arthur Crawford

Master's Theses

No abstract provided.

Determination Of An Enzyme Deficiency In The Saccharomyces Cerevisiae Mutant Mod5-1, Lacking Isopentenylated Trnas, Sopiah Suid

Master's Theses

No abstract provided.

Non-Visual Feeding Behavior Of The Mottled Sculpin Cottus Bairdi: Ecological And Evolutionary Implications, Denise Maxine Denham Hoekstra

Master's Theses

No abstract provided.

Applications Of Aerial Imagery In Identification Of Natural Areas, Kendall Duane Wessel

Dissertations and Theses @ UNI

There is current interest in utilizing aerial imagery to obtain information on natural vegetation. The purpose of this study is to utilize and evaluate commonly available aerial imagery to identify potential natural areas suitable for preservation and to initiate development of a procedure for imagery interpretation to meet this goal.

Clayton County, located in the northeastern quarter of the state of Iowa, was selected for study because it is dissected by steep, narrow stream valleys that are unsuitable for cultivation and may still possess native vegetation of a quality suitable for preservation.

Baseline or control communities were selected from known …