Showing papers by "University of Utah published in 1980"

A Theoretical Development for the Computer Generation and Display of Piecewise Polynomial Surfaces

Abstract: Two algorithms for parametric piecewise polynomial evaluation and generation are described. The mathematical development of these algorithms is shown to generalize to new algorithms for obtaining curve and surface intersections and for the computer display of parametric curves and surfaces.

Sex ratio adaptations to local mate competition in a parasitic wasp.

Abstract: Females of the parasitic wasp Nasonia vitripennis adjust the sex ratio of their broods according to whether they are a first or second wasp to parasitize a host. The first wasp produces a strong daughter bias. The second wasp adjusts the prorportion of sons to the relative level of local mate competition, as predicted by a natural selection model. The results provide a quantitative test of sex ratio theory.

Alternative male life histories in bluegill sunfish

Abstract: Male bluegill sunfish are shown to have two alternative mating strategies: cuckoldry or parental care. Cuckolder males first mature at age 2. They follow a developmental sequence of sneaking and then mimicking female behavior to deceptively gain access to spawnings. Males who become parentals (construct nests, attract females, provide brood care) delay maturation until age 7. The parental investment of these males is parasitized by the cuckolders. This system is an example of a truly parasitically dependent mating strategy in vertebrates. A natural selection model is developed to predict the equilibrium frequencies of the two male types. A preliminary test of the model provides qualitative agreement.

Analytic properties of the vertex function in gauge theories. I

Abstract: The analytic properties of the vertex functions for massless scalar and massless and massive spinor electrodynamics are investigated. First, a general tensor form for the vertex consistent with the Ward identities and free of kinematic singularities is constructed. All of the scalar functions that appear are then calculated to one-loop order in perturbation theory. It is found that in both massive and massless theories the infrared singularities appear in the longitudinal parts of the vertex. The massless theories have additional photon mass-shell singularities which appear in the transverse terms. Complete expressions for each vertex are obtained which contain only one nonelementary function.

Sexual size dimorphism and sexual selection in turtles (order testudines).

Abstract: This paper combines published and original data on sexual size dimorphism, reproductive behavior, and habitat types in turtles. Our major finding is that observed patterns of sexual size dimorphism correlate with habitat type and male mating strategy. (1) In most terrestrial species, males engage in combat with each other. Males typically grow larger than females. (2) In semiaquatic and “bottom-walking” aquatic species, male combat is less common, but males often forcibly inseminate females. As in terrestrial species, males are usually larger than females. (3) In truly aquatic species, male combat and forcible insemination are rare. Instead, males utilize elaborate precoital displays, and female choice is highly important. Males are usually smaller than females. We interpret these correlations between sexual behavior and size dimorphism in terms of sexual selection theory: males are larger than females when large male size evolves as an adaptation to increase success in male combat, or to enable forcible insemination of females. In contrast, males are usually smaller than females where small size in males evolves to increase mobility (and hence, ability to locate females), or because selection for increased fecundity may result in increased female size. In turtle species with male combat or forcible insemination, the degree of male size superiority increases with mean species body size.

Sex change in plants: Old and new observations and new hypotheses

Abstract: Evidence is presented that individuals of a large number of dioecious and subdioecious plant species are able to alter their sexual state in response to changes in the ambient environment and/or changes in size or age. We suggest that lability of sexual expression probably has survival value where a significant portion of the females must otherwise bear the cost of fruit production in unfavorable environments. We demonstrate that in patchy environments of the proper scale and variability in quality, labile sexual expression will enhance an individual's genetic contribution to the next generation.

Solar Tracking by Plants

Abstract: Leaves of many desert and agricultural species have the ability to move diurnally, orienting perpendicular or parallel to the sun's direct rays. This phenomenon is widespread in many plant families and occurs in both C(3) and C(4) photosynthetic pathway plants. In the annual flora of desert communities, solar tracking becomes more frequent as the length of the growing season decreases. Leaves that are perpendicular to the sun's direct rays for tracking appear to have high photosynthetic rates throughout the day, whereas leaves parallel to the sun's rays have reduced leaf temperatures and transpirational water losses.

Apparatus and method for time-domain tracking of high-speed chemical reactions

Abstract: A novel apparatus and method for time-domain tracking of high-speed chemical reactions. The apparatus of this invention includes a feedback system for controlling the RF frequency of an RF radiator system to thereby provide the optimum RF frequency for heating the reaction. The apparatus and method of this invention are particularly useful in the recovery of products from oil shale wherein the oil shale is heated by RF dielectric heating and the feedback system adjusts the RF frequency as the permittivity of the oil shale changes during the heating process.

The influence of codon context on genetic code translation

Abstract: A class of mutations that increase the deficiency of a suppressor tRNA in translating a particular amber codon has been characterized. The increased efficiency is due to a mutation resulting in a change in the mRNA that affects the nucleotide adjacent to the 3' side of the UAG triplet. Thus the interaction of tRNA with mRNA is influenced by mRNA sequences outside the triplet codon.

Process for recovering products from oil shale

Abstract: A process for recovering hydrocarbon products from a body of fragmented or rubblized oil shale. The process includes initiating a combustion zone adjacent the lower end of a body of oil shale and using the thermal energy therefrom for volatilizing the shale oil from the oil shale above the combustion front. Improved recovery of hydrocarbon products is realized by refluxing the heavier fractions in the volatilized shale oil. The heavier fractions are refluxed by condensing the heavier fractions and allowing the resulting condensate to flow downwardly toward the combustion front. Thermal energy from the combustion zone cracks the condensate producing additional lower molecular weight fractions and a carbonaceous residue. The carbonaceous residue is burned in the combustion front to supply the thermal energy. The temperature of the combustion front is maintained by regulating input of oxygen to the combustion zone. The process also includes sweeping the volatilized products from the rubblized oil shale with a noncombustible gas. The flow rate of sweep gas is also controlled to regulate the temperature of the combustion front. The recovered products can be enriched with hydrogen by using water vapor as part of the noncombustible sweep gas and cracking the water vapor with the hot carbon in the combustion front to produce hydrogen and an oxide of carbon.

Flat plate streaming potential investigations: Hydrodynamics and electrokinetic equivalency

Abstract: The accurate measurement of streaming potentials in either capillaries or flat plate systems requires Poiseuille flow, i.e., flow must be steady, incompressible, laminar, and established. The established flow stipulation is rarely addressed yet it is of critical importance. Our findings suggest that while the onset of turbulence causes no abrupt change in the streaming potential, flow must be established throughout at least 90% of the flow field for accurate streaming potential measurement. The development of a flat plate flow system based on (1 × 25 × 75) mm plates is discussed in light of the hydrodynamic requirements. The electrokinetic equivalency between plates and capillaries of the same material is discussed and the small discrepancy is attributed to surface roughness and possible differences in surface chemical composition. The flat plate system offers substantial advantages over capillaries in that both surface treatments and analyses via a variety of quantitative techniques are greatly facilitated.

Control of Adrenal Androgen Secretion

Abstract: I. Introduction The human adrenal cortex secretes a variety of androgens, as shown in Fig. 1, in addition to cortisol and aldosterone. Some of these steroids function as androgens, or serve as precursors for androgen or estrogen formation in peripheral tissues. The control of glucocorticoid and mineralocorticoid secretion is largely under the influence of ACTH and the renin-angiotensin system, respectively. However, the mechanism of control of adrenal androgen (AA) secretion is less well defined, and is the main subject of this review. II. ACTH, Dexamethasone and AAs ACTH is the most widely accepted modulator of AA secretion at present. Rosenfield et al. (1) studied endogenous cortisol and dehydroepiandrosterone (DHA) secretion in a normal volunteer and found a correlation between the rhythmicity of secretion of cortisol and DHA, although the magnitude of the DHA rhythm was much less than that of cortisol. Other investigators have administered bovine ACTH or synthetic forms such as the peptide-(l–24) cosy...

The interaction of plasma proteins with polymers. I. Relationship between polymer surface energy and protein adsorption/desorption

Abstract: Adsorption of bovine albumin, gamma-globulin and fibrinogen from phosphate buffer solution (pH = 7.5) onto several polymer films was studied using the radioiodinated proteins (125I). The kinetics of desorption of the proteinated polymer films in bovine plasma was determined. Contact angle measurements on these same polymers allowed the calculation of dispersive (WA d) and polar (Ip) components of the polymer-protein solution system. Results from these measurements show that the nondispersive-dispersive force balance at the polymer-protein solution interface, expressed by the Ip/WA d ratio, is an important factor for binding of proteins on polymer surfaces. The purity of fibrinogen and the cleaning procedures for the polymer surfaces influence the absolute values of proteins adsorbed on polymer surfaces.

Vole population cycles: A case for kin-selection?

Abstract: Kin-selection, as evidenced by aggression between individuals with a low coefficient of relation, may be a significant contributing factor in vole population cycles. Demographic and behavioral studies support this idea.

Subcutaneous peritoneal injection catheter

Abstract: A novel implantable, peritoneal injection catheter apparatus and method, the apparatus including an open top, fluid-receiving reservoir mounted to one end of a hollow stem and a penetrable membrane covering the open top of the receiving reservoir. The hollow stem is configurated to extend into the peritoneal cavity and includes a retaining flange system for retaining the hollow stem in fluid communication with the peritoneal cavity. The penetrable membrane serves as an injection site for inserting a hollow needle into the receiving reservoir. The penetrable membrane also includes a dome configuration that may be depressed to expel injection fluids from the reservoir into the peritoneal cavity. A substantial portion of the injection catheter is covered with a velour coating to accomodate tissue ingrowth for further securement of the catheter in the tissue of the abdominal wall.

Constructing Lens Spaces by Surgery on Knots.

Abstract: The Göttingen State and University Library provides access to digitized documents strictly for noncommercial educational, research and private purposes and makes no warranty with regard to their use for other purposes. Some of our collections are protected by copyright. Publication and/or broadcast in any form (including electronic) requires prior written permission from the Goettingen Stateand University Library. Each copy of any part of this document must contain there Terms and Conditions. With the usage of the library's online system to access or download a digitized document you accept there Terms and Conditions. Reproductions of material on the web site may not be made for or donated to other repositories, nor may be further reproduced without written permission from the Goettingen Stateand University Library For reproduction requests and permissions, please contact us. If citing materials, please give proper attribution of the source.

The quantity and distribution of radiolabeled dexamethasone delivered to tissue by iontophoresis.

Abstract: A pilot study was conducted in the first of two monkeys using either radiolabeled Dm-Na-P or radiolabeled hydrocortisone sodium succinate, together with lidocaine HCl. This study indicated an approximately tenfold increase in the quantity of Dm-Na-P delivered to the test electrodes (4 mA; 20 minutes) whereas the quantity of hydrocortisone delivered from the test electrodes was only marginally (approximately 10%) increased as compared with that from the controls. In terms of an anti-inflammatory activity, the effective dose of Dm-Na-P in all tissue layers underlying the test electrodes was at least tenfold that of the hydrocortisone. Therefore, further trials with hydrocortisone were abandoned. In the second animal, positive test electrodes (5 mA; 20 minutes, were sited over five joints on the right side of the body and matching control electrodes (0 mA; 20 minutes) were placed over corresponding joints on the left side of the body. The control and test electrodes each contained 1.0 ml tritium-labeled Dm-Na-P (approximately 4.0 mg) and 2.0 ml 4% lidocaine HCl (80 mg). Local tissue concentrations of Dm-Na-P were higher than those that would be obtained by systematic therapy and lower than would be obtained by local injection.

Model for regulation of the histidine operon of Salmonella

Abstract: A model is proposed that accounts for regulation of the histidine operon by a mechanism involving alternative configuration of mRNA secondary structure (the alternative stem model). New evidence for the model includes sequence data on three regulatory mutations. The first (hisO1242) is a mutation that deletes sequences needed to form the attenuator mRNA stem and causes constitutive operon expression. The second mutation (hisO9654) is a His- ochre (UAA) mutation in the leader peptide gene; the existence of this mutation constitutes evidence that the leader peptide gene is translated. The third mutation (hisO9663) is remarkable. It neither generates a nonsense codon nor affects a translated sequence; yet, it is suppressible by amber suppressors. We believe this mutation causes a His- phenotype by interfering with mRNA secondary structure. The suppressibility of the mutation is probably due to disruption of the attenuator stem by ribosomes that read through the terminator codon of the leader peptide gene. This explanation is supported by the observation of derepression of a wild-type control region in the presence of an amber suppressor. Evidence is presented that hisT mutants (which lack pseudouridine in the anticodon arm of histidine tRNA) may cause derepression of the his operon by slowing protein synthesis in the leader peptide gene.

Overlapping genes at the cheA locus of Escherichia coli

Abstract: The cheA locus of Escherichia coli, which is required for chemotactic behavior, encodes two polypeptide products designated p[cheA]L and p[cheA]S. The mode of synthesis of these two proteins was investigated by transferring various missense and nonsense mutations to a lambda transducing phage and observing the mutant cheA products made after infection of ultraviolet-irradiated host cells. Missense mutations had no effect on either the size or the relative amounts of the two cheA polypeptides. Most nonsense mutations caused premature translational termination of both cheA products, indicating that p[cheA]L and p[cheA]S must be translated from the same coding sequence in the same reading frame. Two exceptional nonsense alleles at the promoter-proximal end of cheA made an intact p[cheA]s but no detectable p[cheA]L. These findings show that the cheA locus may contain two different sites for initiation of translation. The synthesis of both proteins can be effected by the same promoter, but it is not yet clear whether both are translated from identical mRNA molecules. Complementation studies of cheA mutants provided evidence for two functional activities, one associated with the amino terminus of p[cheA]L and the other with the common portions of p[cheA]L and p[cheA]S. It is possible that each cheA product has a different function required for chemotaxis. The possible roles of these two products and the functional significance of bacterial genes with overlapping coding sequences are discussed.

Association of viral and Mycoplasma pneumoniae infections with acute respiratory illness in patients with chronic obstructive pulmonary diseases.

Abstract: The relative importance of respiratory virus and M. pneumoniae infections as causes of acute respiratory illnesses was studied over an 8 yr period in 150 subjects who were normal or who had varying degrees of chronic obstructive pulmonary disease (COPD). Viral or M. pneumoniae infections were associated with 186 of 1,030 (18%) illnesses studied, whereas these infections were detected in only 86 of 1,398 (6%) illness-free periods (P less than 0.01). Rhinoviruses, influenza viruses, parainfluenza viruses and coronaviruses were each significantly associated with acute respiratory illnesses. The occurrence of acute respiratory illnesses and viral infections was the same in subjects with moderate to severe COPD as it was in subjects who were normal or who had mild disease.

Interrupted time-series analysis and its application to behavioral data.

Abstract: This paper uses a question-and-answer format to present the technical aspects of interrupted time-series analysis (ITSA). Topics include the potential relevance of ITSA to behavioral researchers, serial dependency, time-series models, tests of significance, and sources of ITSA information.

Suppression of acoustic noise in speech using two microphone adaptive noise cancellation

Abstract: Acoustic noise with energy greater or equal to the speech can be suppressed by adaptively filtering a separately recorded correlated version of the noise signal and subtracting it from the speech waveform. It is shown that for this application of adaptive noise cancellation, large filter lengths are required to account for a highly reverberant recording environment and that there is a direct relation between filter misadjustment and induced echo in the output speech. The second reference noise signal is adaptively filtered using the least mean squares, LMS, and the lattice gradient algorithms. These two approaches are compared in terms of degree of noise power reduction, algorithm convergence time, and degree of speech enhancement. Both methods were shown to reduce ambient noise power by at least 20 dB with minimal speech distortion and thus to be potentially powerful as noise suppression preprocessors for voice communication in severe noise environments.

Ultrastructure of secondary neurulation in the chick embryo

Abstract: Formation of the future lumbosacral level of the spinal cord was studied in two-day-old chick embryos by light and electron (transmission and scanning) microscopy. A neurulation overlap zone occupied this level. The dorsal portion of the neural tube formed by bending of the neural plate and approximation and fusion of neural folds (i.e., by primary neurulation), and the ventral part formed during secondary neurulation by cavitation of an initially solid, compact mass of cells, the medullary cord, derived from the tail bud. Secondary neurulation involved four morphogenetic processes: (1) segregation of the cells of the prospective medullary cord from cells of adjacent regions, (2) formation of a precisely delimited medullary cord, (3) cavitation of the central portion of this cord, and (4) coalescence of all lumina into a single, central cavity. Cell segregation was associated with the formation of a layer of primarily extracellular materials between adjacent organ rudiments. The source and composition of these materials are unknown. Formation of the medullary cord entailed considerable elongation of the peripheral cells of this developing structure and the fabrication of small intercellular juctions, first at the basal (outer) ends of the elongating peripheral cells, and then at their apical (inner) ends. These arranged, columnar cells, having characteristics similar to those of the neural plate, and an inner cluster of irregularly shaped and arranged cells. Cavitation always occurred first at the junction between these two cellular populations. The central cells of the medullary cord also eventually elongated, like the peripheral cells, and may have been intercalated into the lateral walls of the developing neural tube as lumina coalesced.