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A Paleontological Review Of Three Billfish Families (Istiophoridae, Xiphiidae, And Xiphiorhynchidae), Harry L. Fierstine

Biological Sciences

No abstract provided.

Extracting Chemical Information From Auger Line Shapes, David E. Ramaker

Scanning Microscopy

We have developed a generally applicable, semi-empirical approach for quantitatively interpreting Auger line shapes. Detailed information on hybridization, electron delocalization and correlation, screening effects, bonding, and covalency can be obtained from the line shape. Methods for extracting the Auger line shape from the experimental data are briefly described. We summarize our recent results from the C KVV Auger line shapes of five different gas phase hydrocarbons (methane, ethane, cyclo-hexane, benzene, and ethylene), three solids (polyethylene, diamond, and graphite), and a molecularly chemisorbed system (ethylene/ Ni). The normal kvv component accounts for only about half of the total experimental KVV intensity …

Secondary Electron Emission From Solids. Ii. Theoretical Descriptions, Michel Cailler, Jean-Pierre Ganachaud

Scanning Microscopy

A primary beam impinging on a solid target suffers elastic and inelastic collisions with the components of the solid. These collisions can be incorporated into a Monte-Carlo simulation model if all the cross sections associated with the various types of collisions are known.

Elastic diffusion effects are mainly related to the interactions of the particles with the real potential V(r) surrounding each ionic core. An essential simplification of the inelastic interactions is to consider that the solid reacts as a whole to an external probe, which is the incident electron beam. The linear response of the solid to an external …

Food Quality, Heterozygosity, And Fitness Correlates In Peromyscus Polionotus, James M. Novak, William R. Teska, Michael H.. Smith

Faculty Research & Creative Activity

Oldfield mice (Peromyscus polionotus) that are more heterozygous utilize food and maintain body weight under varying degrees of dietary stress better than their less heterozygous counterparts. Mice were collected in southern Florida and fed diets of three qualities. During each dietary treatment, body weight, amount of food eaten, amount of food absorbed, and feeding efficiency were determined. Body weights for all mice decreased during the experiment. More heterozygous mice maintained their weight better during periods of dietary stress than those that were less heterozygous. Mice with different levels of genetic variability had essentially the same mean feeding efficiency with high …

Documented Chromosome Numbers 1990: 1. Miscellaneous North American Vascular Plants, Bruce D. Parfitt, Donald J. Pinkava, Debbie Rickel, Dan Fillipi, Beth Eggers, David J. Keil

Biological Sciences

The following meiotic chromosome counts are documented by specimens deposited in Herbarium of Arizona State University (ASU). Previously uncounted taxa are represented by an asterisk (*). A double asterisk (**) indicates a new number for the species.

Plasmons In Scanning Transmission Electron Microscopy Electron Spectra, R. H. Ritchie, A. Howie, P. M. Echenique, G. J. Basbas, T. L. Ferrell, J. C. Ashley

Scanning Microscopy

A general self-energy formulation of the interaction between an electron in a scanning transmission electron microscope (STEM) and a localized target is given. We prove a theorem relating the probability of energy transfer to that calculated classically. Local dielectric theory of target excitation for various geometries is discussed. The problem of localization of initially unlocalized excitations in the valence band of solids is treated by transforming cross sections differential in momentum transfer into dependence on an impact parameter variable. We are thereby able to account for experimental data in scanning electron microscopy (SEM) that show high spatial resolution.

Energy Loss Of Electrons Below 10 Kev, Hans Bichsel

Scanning Microscopy

Monte Carlo calculations are used to obtain the energy loss and spatial distribution of electrons penetrating matter. For this purpose, reliable cross section for the inelastic collisions must be known. As an approximation valid for large energy losses, the Coulomb cross section can be used. It can be modified in a simple way to account for the binding of electrons and for the exchange effect. In the Gryzinski model, collisions with moving electrons are assumed. In the quantum mechanical Bethe approximation, σ is closely related to the dipole oscillator strength (DOS), and its extension to finite momentum transfers, the generalized …

Slowing Down Of Positrons And Applications To Solid Surfaces, Peter J. Schultz, L. R. Logan, W. N. Lennard, G. R. Massoumi

Scanning Microscopy

When monoenergetic positrons enter a solid they scatter and lose energy via processes similar to those for electrons. Theoretical details of these processes have been well established for decades, but experimental results using low energy positron beams are only now becoming available for comparison. We review the theoretical results for elastic and inelastic scattering of positrons and the predictions that follow for backscattering, inner-shell ionization, energy loss and stopping profiles. In this presentation, emphasis is given to specific comparisons with calculations for electrons. We discuss recent experimental results in each of these areas, and conclude with two examples of applications …

Slowing Down And Scattering Of Ions In Solids, W. Heiland, H. Derks, T. Bremer

Scanning Microscopy

The interaction of particle beams with solids yields three parts, i.e. reflected particles, penetrating particles and trapped particles. At very low energies particle reflection is dominant, at very high energies penetration is the most important effect. Trapped particles are the result of energy loss processes, which on the other hand cause radiation damage in the solid. In the energy range discussed here, i.e. above energies where quantum effects, diffraction etc. are important and below energies where nuclear reactions, relativistic effects etc. may occur, the particle trajectories are classical. The energy loss process can be treated separately as nuclear and electronic …

Migration Routes Of New World Sanderlings (Calidris Alba), J. P. Meyers, M. Sallaberry A., E. Ortiz, G. Castro, L. J. Gordon, John L. Maron, C. T. Schick, E. Tablio, P. Antas, T. Below

Biological Sciences Faculty Publications

We color-marked Sanderlings (Calidris alba Pallas) at 19 locations in 6 countries in the New World and coordinated a network of volunteers to locate banded individuals in migration over a five-year period. The observers reported 252 independent sightings of birds in countries different from the country of banding. Sanderlings that migrate north to the Arctic from Chile and Peru travel principally through the central corridor (Texas and northward) of the United States and Canada; smaller numbers follow the Pacific coast. A few migrate north from the Pacific coast of South America along the Atlantic coast of the United …

Angular And Energy Distributions Of Electrons Emitted From Gases And Thin Foils During Light Ion Bombardment, L. H. Toburen

Scanning Microscopy

The energy and angular distributions of electrons ejected by fast charged particles in ionizing collisions provide detailed information regarding the effects of atomic, molecular, and condensed-phase structure on the energy loss process. Analysis of the wide range of available data has lead to several general conclusions. For ionization of atomic and molecular targets by protons having energies above a few hundred keV, the cross sections for electron production have been found to scale as the number of loosely bound target electrons. The more subtle features of the ejected electron energy spectra are, however, dependent on the electronic structure of the …

Electron Stimulated Surface Chemistry, Miles J. Dresser

Scanning Microscopy

When an electron beam of less than 1000 eV interacts with a surface layer a variety of phenomena may occur. In this paper I will discuss those interactions that lead to either chemical changes on the surface and/or desorption of species or fragments from the surface. Theoretical models of electron stimulated desorption, (ESD) will be presented, specifically the Menzel, Gomer, and Redhead model, the Knotek, Feibelman model and the Ramaker, White and Murday model. Experiments that display the angular distribution of the desorbing ionic or metastable fragments, (referred to as ESDIAD for Electron Stimulated Desorption: Ion Angular Distributions) are the …

Physical Sputtering Of Metallic Systems By Charged-Particle Impact, Nghi Q. Lam

Scanning Microscopy

The present paper provides a brief overview of our current understanding of physical sputtering by charged-particle impact, with the emphasis on sputtering of metals and alloys under bombardment with particles that produce knock-on collisions. Fundamental aspects of ion-solid interactions, and recent developments in the study of sputtering of elemental targets and preferential sputtering in multicomponent materials are reviewed. We concentrate only on a few specific topics of sputter emission, including the various properties of the sputtered flux and depth of origin, and on connections between sputtering and other radiation-induced and -enhanced phenomena that modify the near-surface composition of the target. …

Ion-Induced Electron Emission From Solids, Wolfgang O. Hofer

Scanning Microscopy

A review of ion-induced electron emission is presented which concentrates on the mechanisms relevant to imaging, analysis, and processing of surfaces by ion beams. In this field of applications, the main interest in electron emission lies in kinetic emission by heavy, i.e. multi-electron (Z > 2) ions of energy ≤ 100 keV.

Interband Transitions In Electron Energy Loss Spectrometry, P. Schattschneider, P. Pongratz

Scanning Microscopy

Electron energy loss spectrometry (EELS) allows one to experimentally obtain the dielectric permittivity 𝜀:(ω, q) as a function of frequency ω and wave vector if. From 𝜀 information on inter band transitions in the probed medium can be drawn. In EELS, inter band transitions are screened by the movement of the loosely bound valence or conduction electrons. The screening effect may enhance or attenuate the strength of transitions, and tends to shift the frequencies of resonant oscillations. Another aspect of screening is the occurrence of longitudinal modes in the spectrum. So, great care has to be taken in interpreting …

Compton Scattering In Electron Energy Loss Spectrometry, P. Schattschneider, P. Pongratz, H. Hohenegger

Scanning Microscopy

It is well known that the distribution of electron momenta (electron density in momentum representation) of gases can be probed by Compton scattering of either photons (γ-rays or X-rays) or electrons. Recently it has been shown that Compton scattering of electrons is suited to the study of the electron momentum densities of solids on a microscopic scale. This technique, known as ECOSS, Electron Compton Scattering from Solids can be done in the electron microscope by electron energy loss spectrometry (EELS).

After a discussion of inherent approximations and the introduction of the reciprocal form factor a method is proposed in order …

Spatially Sensitive Electron Energy Loss Spectroscopy, Helmut Kohl

Scanning Microscopy

Over the last decade electron energy loss spectroscopy has been increasingly used as a microanalytical technique. Under favorable conditions a spatial resolution better than 1 nm has been achieved. It is therefore possible to obtain spectroscopic information at an atomic scale. Such a spectrum can be used for the investigation of

- the elemental composition

- defect levels

- surface excitations

- the fine structure.

The spatial sensitivity of such experiments implies, that the initial or the final state of the scattered electrons must have a spatial structure. The theory for the scattering of wave packets will be discussed, focussing …

Secondary Electron Emission From Solids. I. Secondary Electron Spectroscopy, Michel Cailler, Jean-Pierre Ganachaud

Scanning Microscopy

The secondary electron emission spectroscopy can provide useful information about the transitions in the electronic structure from solids and deals with the detection of fine structures superimposed on the true secondary peak, in the kinetic energy range of the true secondary electrons.

Several mechanisms have been proposed for the creation of these fine structures: diffraction phenomena, plasmon decay, interband transitions to unoccupied levels, Auger transitions and more recently, autoionization emission. Some features could not be explained as being due to any bulk effect and were considered as indicative of a need to include surface wave-matching arguments in the analysis of …

Monte Carlo Simulation Of Secondary Electrons In Solids And Its Application For Scanning Electron Microscopy, M. Kotera, T. Kishida, H. Suga

Scanning Microscopy

A new Monte Carlo calculation model is introduced to simulate not only the primary electron behavior but also the secondary electron cascade in a specimen bombarded with an electron beam. Either the primary or the generated electron in a specimen having energy greater than 0.1 keV is defined as a fast electron and the single scattering model is used in the simulation which employs the Mott elastic scattering cross section and the Rao Sahib-Wittry energy loss equation. The electron having energy smaller than 0.1 keV is defined as a slow electron and the cascade model is used which takes into …

Channelling And Related Effects In Electron Microscopy: The Current Status, Kannan M. Krishnan

Scanning Microscopy

The channelling or Borrmann effect in electron diffraction has been developed into a versatile, high spatial resolution, crystallographic technique with demonstrated applicability in solving a variety of materials problems. In general, either the characteristic x-ray emissions or the electron energy-loss intensities are monitored as a function of the orientation of the incident beam. The technique, as formulated in the planar geometry has found wide applications in specific site occupancy and valence measurements, determination of small atomic displacements and crystal polarity studies. For site occupancy studies, the appropriate orientations in most cases can be determined by inspection and the analysis carried …

Electron Beam Nano-Etching In Oxides, Fluorides, Metals And Semiconductors, C. J. Humphreys, T. J. Bullough, R. W. Devenish, D. M. Maher, P. S. Turner

Scanning Microscopy

Etching, lithography, hole formation, surface restructuring and external machining can all be performed on a nanometre scale using an intense electron beam. Results are presented for a range of different materials which demonstrate the variety of mechanisms by which electron beam nano-etching can occur. For example, in crystalline 13-alumina hole formation occurs by surface indentations growing inwards to join up and form a nanometre diameter hole. In amorphous alumina, on the other hand, hole formation is from the inside-out: oxygen gas bubbles form under the electron beam, coalesce, and burst to leave a well defined nanometre diameter hole. In MgO …

Adaptive Coloration In Texas Fiddler Crabs (Uca), Carl L. Thurman

Faculty Work

Five species of fiddler crabs occupy a variety of intertidal niches along the Texas coast. Each Uca is adapted to a specific array of physical factors in the environment. Some aspects of their adaptations are reflected by body color. Interspecific differences in morphological coloration are correlated with camouflage and substrate characteristics. Intraspecific color variation is expressed through neurosecretion-mediated physiological change in cellular pigment distribution. Adaptation to a dark or light colored background reveals different "secondary" chromomotor capabilities for each species. In addition, pigments in melanophores, leucophores and erythrophores exhibit circadian rhythms of dispersion and aggregation.

During a "primary" chromomotor response …

Systematic Relationships Of Rhinolophid Bats: Based On Hyoid Morphology, Andrea L. Smith '90

Honors Projects

The hyoid regions of three species of bats within the family Rhinolophidae were dissected and compared with similar data of the hyoid region of other families obtained from Griffiths (personal communication). A cladistic analysis was performed using these data to analyze inter-generic relationships within the Rhinolophidae and inter-familial relationships between the families Rhinolophidae, Megadermatidae, Nycteridae, Rhinopomatidae and Emballonuridae. Two possible inter-generic cladograms are most parsimonious. Within the rhinolophids, either Hipposideros diadema or Hipposideros armiger is the most distantly related species depending on which of two characters, loss of the sphincter colli or loss of the omohyoid, has undergone convergent evolution. …

Identification Of An Escherichia Coli Genetic Locus Involved In Thermoregulation Of The Pap Operon, C. A. White-Ziegler, L. B. Blyn, B. A. Braaten, D. A. Low

Biological Sciences: Faculty Publications

We previously showed, using a single-copy papBAp-lac fusion (previously designated papBA-lac), that pyelonephritis-associated pili (pap) pilin gene transcription is subject to both phase variation and thermoreg- ulatory control mechanisms (L. B. Blyn, B. A. Braaten, C. A. White-Ziegler, D. H. Rolfson, and D. A. Low, EMBO J. 8:613-620, 1989). At 37°C, Escherichia coli strains carrying the papBAp-lac fusion displayed both Lac' and Lac- colony phenotypes. In contrast, at 23°C, colonies displayed a uniform Lac- phenotype, suggesting that pilin was not transcribed at this temperature. In this study, a strain carrying the papBAp-lac fusion was subjected to mini-TnlO (mTnlO) mutagenesis to …

Investigation Of Resistance Of The Cotton Mouse, House Mouse, Guinea Pig And Broad-Headed Skink To Larvae Of The Blacklegged Tick, Ixodes Scapularis Say (Acari: Ixodidae), Jordi L. Galbe

College of Graduate Studies: Theses & Dissertations (1964–2006)

Mus musculus , the house mouse (laboratory strain), Peromyscus gossypinus. the cotton mouse, Eumeces laticeps. the broad-headed skink, and Cavia porcellus, the guinea pig, were successively infested five times with larvae of Ixodes scapularis. the blacklegged tick. Tick feeding success, engorgement weight and molting success were measured after each infestation. In general, a greater percentage of ticks (PM. musculus and E. laticeps than on P. gossypinus or Q. porcellus. P. gossypinus expressed partial resistance, measured in percentage of ticks feeding, during the third infestation, but showed increased tolerance during the fourth and …

Field Notes, Joseph A. Cook

Division of Mammals - Field Notes and Catalogs

No abstract provided.

Heat Dissipation, Gas Exchange And Acid-Basic Balance In The Land Snail Oreohelix During Short-Term Estivation, Bernard Rees

Biological Sciences Faculty Publications

Within 4 days following entry into estivation, heat dissipation and oxygen consumption by the land snail Oreohelix spp. decreased by 83 % compared to standard non-estivating rates. During both non-estivating and estivating conditions, the quantity of heat dissipated per mole of O2 consumed was indicative of a completely aerobic metabolism. This calorimetric-respirometric (C/R) ratio was — 461 ± 12 kJ moP102 (S.E.M., N=5) under standard non-estivating conditions and — 464±26kJmol~1O2 (7V=4) during estivation. Respiratory exchange ratios reflected a primary dependence upon carbohydrate as a metabolic substrate during both states. Carbon dioxide retention occurred during the first 36h of estivation, resulting …

Regulation Of Fatty Acid Biosynthesis By Physical Exercise Mechanisms Of Inhibition, Rita Priyadarshani Francis

Master's Theses

In partially purified cell-free extracts of rat liver, nonexhaustive, daily exercise results in a 40 to 90% inhibition of FAB by decreasing the catalytic activity of acetyl coenzyme A carboxylase (ACC), the rate-limiting enzyme in the de novo FAB pathway in vitro. ACC inhibitory mechanisms are postulated to include: phosphorylation of ACC and production of a noncompetitive inhibitory substance.

Data obtained after purification of rat liver ACC to homogeneity suggest that decreased ACC activity in exercised rats cannot be attributed to the well-documented control of ACC by reversible phosphorylation, but are more likely due to the presence of a noncompetitive …

The Functional Organization Of The Vestigial Locus In Drosophila Melanogaster, Jim A. Williams, Audrey L. Atkin, John B. Bell

School of Biological Sciences: Faculty Publications

Vestigial mutants are associated with imaginal disc cell death which results in the deletion of adult wing and haltere structures. The vestigial locus has previously been cloned, and mutational lesions associated with a number of vg alleles were mapped within a 19 kb DNA region defined as essential for vg function. Herein we report the identification and characterization of a developmentally regu-lated 3.8 kb vg transcript which is spliced from exons distributed throughout the essential interval defined above. All the characterized classical alleles have predictable effects on this transcription unit, and the severity of this effect is directly proportional to …

Construction Of An Opal Suppressor By Oligonucleotide-Directed Mutagenesis Of A Saccharomyces Cerevisiae Trna Gene, Audrey L. Atkin, K. L. Roy, J. B. Bell

School of Biological Sciences: Faculty Publications

In vitro mutagenesis was used to create putative opal suppressor alleles of a tRNA^Trp gene of Saccharomyces cerevisiae. The construct with the requisite anticodon change did not result in an active suppressor, whereas when a second change was introduced into the portion of the gene encoding the intron, an active and specific opal suppressor was produced. We propose that the secondary structure of transcripts from the first mutant may prevent efficient pre-tRNA processing, whereas normal processing occurs with the double mutant.