Showing papers by "University of Nebraska–Lincoln published in 1973"

Impact Excitation and Polarization of the Emitted Light

Abstract: A new formulation is presented for the angular distribution and the polarization of light excited by atomic and electronic collisions and modulated in time by the action of internal and external fields. The formulation disentangles geometrical and dynamical effects and stresses the extraction of data on the alignment and orientation of radiating atoms from observations of the emitted light. The treatment is set in the context of recent experimental and theoretical literature and points to new avenues of research.

Bacteriophage φ6: a Lipid-Containing Virus of Pseudomonas phaseolicola

Abstract: The purification and properties of a lipid-containing bacteriophage, phi6, are described. The phage contains a lipid envelope which is probably essential for infection. Infectivity of phi6 was lost in the presence of organic solvents, sodium deoxycholate, and phospholipase A. The fatty acid composition of the phage lipid was similar to that of the Pseudomonas phaseolicola host cells. The phage was composed of about 25% lipid, 13% RNA, and 62% protein. The buoyant density of phi6 was 1.27 g/ml in cesium chloride. The morphology of phi6 was unusual; it had a polyhedral head of about 60 nm surrounded by a membranous, compressible envelope which appeared to assume an elongated configuration upon attachment to pili. The adsorption rate constant was 3.3 x 10(-10) ml/min in a semi-synthetic medium and 3.8 x 10(-10) ml/min in a nutrient broth-yeast extract medium. The latent period was shorter in the former medium (80-115 min compared with 120-160 min), and the average burst size was larger (250-400 compared with 125-150). The eclipse period coincided with the latent period.

Toxin from Fusarium moniliforme: Effects on Plants and Animals.

Abstract: A mycotoxin-producing strain of Fusarium moniliforme was isolated from southern leaf blight-damaged corn seed. A water-soluble toxin, subsequently purified from the fungus, had an oral median lethal dose of 4.0 milligrams per kilogram in 1-day-old cockerels. The toxin also produced plant growth-regulating and phytotoxic effects on plant systems. Physical and chemical data presented for the toxin suggest a structurally new toxin. The trivial name "moniliformin" has been assigned to the toxin.

Pathology of neonatal calf diarrhea induced by a coronavirus-like agent.

Abstract: Lesions induced by a bovine coronavirus-like agent were studied in gnotobiotic and colostrum-fed calves using gross, histologic and electron microscopic procedures. Lesions in gnotobiotic calves we...

Aggregation of soil particles by algae1

Abstract: SUMMARY Chlorella pyrenoidosa Chick (Indiana University Number 252), Nostoc commune Vaucher (I.U. 584), and Oscillatoria prolifica (Grev.) Gomont (I.U. 1270) were grown separately on Peoria loess soil material to measure their effects on the water stability of soil aggregates. Each alga significantly (10% LSD) increased the percentage of soil aggregates after 6 weeks of incubation as compared with the soil without algae. Oscillatoria, Chlorella, and Nostoc increased water stability of aggregates >74 μ in diameter by 3.4, 1.1, and 0.6%, respectively. Nostoc and Oscillatoria produced measurable water stable aggregates in the 1000–2000 μ diameter range; Chlorella formed them in the 500–1000 μ range, while the control soil showed no aggregates >295 μ.

Nonlinear Layered Analysis of RC Plates and Shells

Abstract: A layered nonlinear finite element analysis including the elastoplastic behavior of steel, bilinear elastoplastic behavior of concrete, and limiting tension of concrete is presented. The incremental-variable elasticity analysis technique is used to obtain the load deflection curve for any general plate or shell. The need for a shear retention factor to provide the torsional and shear stiffness for cracked concrete is examined. The failure of the constitutive relations for a layered material to uncouple and the resulting importance of the inplane degrees-of-freedom is also considered. Finally, some numerical examples, both plates and shells, are presented to demonstrate the accuracy of the incremental analysis.

Resonances in the angular distribution of xenon photoelectrons

Abstract: Measurements are reported of the resonant structure, caused by autoionization, in the angular distribution of xenon photoelectrons. The measurements were made within the autoionizing structure lying between the $^{2}P_{\frac{3}{2}}$ and $^{2}P_{\frac{1}{2}}$ ionization thresholds for the wavelength range 956 to 1015 \AA{}. The results show a periodic variation in the asymmetry parameter $\ensuremath{\beta}$ with maximum excursions of about + 0.9 to - 0.9. The overall variation and magnitude of $\ensuremath{\beta}$ is in accord with the recent theoretical predictions of Dill.

Belief in Supernatural Phenomena and Locus of Control

Abstract: It is hypothesized that Rotter's I-E variable mediates individual differences in supernatural and superstitious beliefs, with externals exhibiting more positive attitudes toward such phenomena. An approximately equal number of male and female introductory psychology students were selected as externals (N = 20) and internals (N = 23) from upper and lower quartiles of the Rotter I-E scale. All Ss were administered an attitude questionnaire assessing beliefs toward several paranormal, occult, and pseudoscientific phenomena. Analysis via a 2 × 2 (I-E Control × Sex) analysis of variance strongly confirmed the hypothesis (p < .01). Although not predicted, females, regardless of I-E status, were much more favorably disposed toward such phenomena than males (p < .01). Differences in more general attitudes toward both religion and science are suggested as mediating the over-all I-E and sex differences.

RNA Polymerase Activity Associated with Bacteriophage φ6

Abstract: The Pseudomonas phaseolicola bacteriophage phi6 incorporated labeled UTP into an acid-insoluble precipitate. Incorporation was dependent on the presence of manganese acetate, ATP, GTP, CTP, and a short heat treatment of the phage; the reaction was stimulated by NH(4)Cl. The substitution of (14)C-ATP, -CTP or -GTP for UTP, together with the appropriate unlabeled ribonucleoside triphosphates, disclosed that CMP was incorporated to the greatest extent followed by GMP, UMP, and AMP. Radioactive RNAs formed by the reaction were resistant to RNases A and T(1) in high salt but susceptible to these nucleases in low salt. The labeled RNA co-sedimented and co-electrophoresed with phi6 double-stranded (ds) RNA. However, the distribution of the radioactivity into the three ds-RNA components varied depending on the (14)C-ribonucleoside triphosphate used in the reaction. The incorporation of UMP was primarily into the two smaller ds-RNA segments, GMP primarily into the large ds-RNA segment, and CMP and AMP were about equally distributed into all three ds-RNA segments.

On Detecting Demand Awareness by Postexperimental Questionnaire

Abstract: Summary The most serious error that can occur in assessing demand awareness by postexperimental questionnaire is to score an actually aware subject as unaware (false-negative problem). Compared to this the scoring of an actually unaware subject as aware (false-positive problem) is of minor importance. In this study 576 subjects were exposed to a deception experiment and then given one of three types of awareness questionnaire (indirect, direct, or funnel). Each questionnaire type either included or did not include an orienting paragraph and saliency-control questions. The funnel questionnaire was found to be the most accurate method of assessing awareness. It misclassified few subjects who were aware by an objective criterion, while not picking up too many false positives in the process. The belief that an extended-funnel questionnaire will “suggest” too much demand awareness after the fact is challenged; the data do not support this notion.

Neonatal Calf Diarrhea. Electron Microscopy of Intestines Infected with a Reovirus-Like Agent

Abstract: Neonatal calf diarrhea induced by a reovirus-like agent was studied by electron microscopy. Gnotobiotic calves were inoculated with virulent and cell-culture- adapted isolates of viruses, and similar results were obtained with both isolates. The virus infected mature villous epithelial cells of the small intestine and replicated predominantly within cisternae of the endoplasmic reticulum. Macrophages within small intestinal villi also contained viral particles. Shedding of virus into the feces apparently resulted from desquaniation of infected epithelial cells. Replacement epithelium did not contain the reovirus-like agent, was of cuboidal or squamous type, and ultrastructurally resembled immature epithelium normally found in the crypts. Escherichia coli was nonpathogenic when inoculated alone and did not adhere to the epithelium when inoculated with the virus. The reovirus-like agent was a primary pathogen since it caused diarrhea and lesions when inoculated alone or with E. coli. Diarrhea of neonatal calves has been a serious and persistent problem of the dairy industry for many years. This disease has become a major problem on ranches with cow-calf operations. Apparently an increased frequency of neonatal calf diarrhea in beef-type calves has been caused by calving during a relatively short period of time in the late winter and early spring when incle- ment weather causes stress. Cows and their offspring have been concentrated into small areas during the calving season, and transmission of infectious di- seases to susceptible calves has been favored. A virus designated initially as neonatal calf diarrhea virus was isolated in 1968 and reported as an etiologic agent in field cases of neonatal calf diarrhea (9). The disease was reproduced experimentally in specific pathogen-free and gnotobiotic calves inoculated with bacteria-free filtrates obtained from in- fected calves. Fecal material purified by ultracentrifugation and examined by

Insect-Control Studies with Microwaves and Other Radiofrequency Energy

Abstract: Recent advances in practical application of microwave power and current interest in physical methods for insect control have given rise to hope that microwave energy might be useful for controlling insects. This is not a new concept. While available information may not be sufficient for detailed evaluation of such potential applications, considerable data are available in the literature concerning the effects on insects of energy in the radiofrequency (RF) region of the electromagnetic spectrum.

Quasi-Landau spectrum of a hydrogen like atom in a high magnetic field

Abstract: A two dimensional semiclassical approximation is used to examine the sigma polarization spectrum of a hydrogen like atom in a strong magnetic field. Resonances above the zero field ionization limit are found and their energy separations are computed over the region from the ionization limit to 40 h(cross) omega c above, where omega c is the cyclotron frequency, for magnetic fields of 10, 17, 25, 32, 40 and 47 kG. At the ionization limit the separation between resonances is found to be 1.500 h(cross) omega c, independent of magnetic field strength, which is in agreement with a separation of 1.5 h(cross) omega c observed experimentally by Garton and Tomkins (1969) in the sigma polarization spectrum of barium in a magnetic field of 24 kG. The energy separations are found to decrease above the ionization limit toward the value h(cross) omega c, which is characteristic of the levels of a free electron in a homogeneous magnetic field.

Heat‐induced changes in extractability of beef muscle collagen

Abstract: Alterations in the extractability of collagen due to heating of beef muscle were determined and compared with shear and penetrometer values. Strips were heated in a water bath programmed to reproduce the internal temperature curve of a roast in a 163°C oven. Samples were removed at internal temperatures of 58, 67, 75 and 82° C. Data were collected on weight of raw and heated meat, amount of juice expressed during heating, moisture, fat and nitrogen content of the meat and juice, total and extractable collagen, and shear force and depth of penetrometer penetration. Solubilized collagen in the heated meat was determined by extraction with water at 40°C. The amount of soluble collagen increased with increasing internal temperature. Comparison of the solubilized collagen data with shear and penetrometer readings suggested that the changes in the contractile fibers influenced texture more than did the changes in the collagen of these muscles under these heating conditions.

Dynamic buckling of a rectangular orthotropic plate

Abstract: The elastic buckling of a simply-supported rectangular orthotropic plate, with initial imperfections, under a rapidly applied compressive load is analyzed. The large deflection plate equations are used to study inertial effects in the postbulkling phase. Numerical results for a controlled rate of load application show that the critical load is increased over the corresponding static case. The load-deflection relation is oscillatory in the postbuckling phase, thereby increasing the stresses in the plate over those in the static case. Initial imperfections decrease the critical load as well as increase the frequency and decrease the amplitude of the oscillations.

Polyribosomes from Peas: II. Polyribosome Metabolism during Normal and Hormone-induced Growth.

Abstract: Polyribosomes as large as 10-mers (strands of messenger RNA bearing 10 ribosomes) were isolated from etiolated pea (Pisum sativum L. var. Alaska) stem tissue during all stages of development when methods were used which essentially eliminated ribonuclease activity during extraction. Actively growing tissue, harvested from the apical 10 mm, yielded many large polyribosomes and a low (<20%) proportion of monosomes. Similar tissue, allowed to age by applying lanolin to decapitated apices, showed a progressive decrease in number of larger polyribosomes and an increase in the proportion of monosomes. Hormone treatments, which prolonged growth and delayed aging, delayed the loss in large polyribosomes and the increase in proportion of monosomes. Growth-stimulating hormones, added to previously aged tissue, stimulated the production of many large polyribosomes in pre-existing cells.It is suggested that (a) large polyribosomes occur in all regions of the pea stem, (b) changes in polyribosome distribution appear to precede changes in growth rate, (c) loss of larger polyribosomes is closely related to a decrease in mRNA templates followed more gradually by loss of ribosomes, (d) hormone-stimulated continuation of growth is accomplished through maintenance of available mRNA.Methods are described, involving detailed analysis of polysome distribution, which, although they cannot be used to measure changes in initiation of ribosomes on to mRNA, do permit measurement of the amount of polysomal-associated mRNA present in tissues at different stages of growth. These analyses lead to the further suggestion that hormone stimulation of growth of previously nongrowing tissue is accomplished primarily through an increase in available mRNA prior to synthesis of ribosomes.

Magnetoresistance in Iron and Cobalt to 150 kOe

Abstract: Magnetoresistance anisotropy and field dependence have been studied in single crystals of iron and cobalt in fields up to 150 kOe in the temperature range 1-4.2 K. The crystals of iron and cobalt had residual resistance ratios up to $\ensuremath{\sim}4600$ and $\ensuremath{\sim}400$, respectively. The relation $\frac{\ensuremath{\Delta}\ensuremath{\rho}}{{\ensuremath{\rho}}_{0}}=a{B}^{n}$ has been studied for both metals and in the case of iron the exponent $n$ approaches values in the range 1.8-1.9 for fields up to 90 kOe and then decreases to the range 1.3-1.5 at 150 kOe. This decrease in the exponent has been observed for all field and current directions measured suggesting that extensive magnetic breakdown may occur. A preliminary measurement on iron to 215 kOe shows $n$ decreasing to less than 1 for some field directions. Cobalt shows saturation behavior for most field and current directions but values of $ng1$ are observed for certain specific directions. The magnetoresistance rotation curves for iron exhibit sharp minima consistent with narrow bands of open orbits in the 100 g and 110 g directions. Minima are also observed which indicate open orbits in the 310 g, 410 g, and 530 g directions. The behavior of cobalt suggests open orbits parallel to the basal plane and possibly along the $c$ axis. Both metals show Shubnikov-de Haas oscillations which appear to be related to small pockets of the Fermi surface corresponding to ${10}^{\ensuremath{-}3}$-${10}^{\ensuremath{-}4}$ electrons per atom. In iron oscillations with frequencies in the range 1-6.2 MG have been observed while in cobalt three oscillations with frequencies of 1.07, 3.57, and 11.63 MG have been observed. The low-frequency oscillation in cobalt has been studied as a function of angle and indicates that two distinct branches exist as the field is rotated away from the $c$ axis. Oscillations are observed on only one branch at a time and the behavior suggests the possible presence of magnetic breakdown. The data on both iron and cobalt have been compared to models of the Fermi-surface topology in these metals.