Showing papers by "University of Nebraska–Lincoln published in 1972"
333 citations
TL;DR: In this paper, the power law was used to assess wind erosion as a source of atmospheric soil particles, and vertical aerosol fluxes near the ground in an eroding field were computed by assuming a vertical transport mechanism similar to that for momentum.
Abstract: To assess wind erosion as a source of atmospheric soil particles, vertical aerosol fluxes near the ground in an eroding field were computed by assuming a vertical transport mechanism similar to that for momentum. Aerosol gradients were measured by jet impactors located 1.5 and 6 m above the ground, and wind velocity gradients were measured by totalizing-three-cup anemometers located 1.5, 3 and 6 m above the ground. Information on the aerosol size distributions and quantity in the size range 0.3 ≤ r ≤ 6 μm was obtained for a variety of erosive conditions in a field in rural Nebraska. In general, the size distributions in this range suggest the power law, dN/d(log r) ∝r−2 for 1 ≤ r ≤ 6 μm, and a flatter curve for 0.3 ≤ r ≤ 6 μm. The relation of the aerosol size distribution in the range 0.3 ≤ r ≤ 6 μm to the size distribution of soil was determined. Averaged soil size distributions characteristic of the sampling field, the area within a six-mile radius of the sampling field, and soil flowing (creep...
177 citations
TL;DR: The data presented suggest that buffer of high ionic strength and high pH was more effective in preventing degradation of polyribosomes than was diethyl pyrocarbonate and, furthermore, that ratios involving large poly ribosomes (hexamers and larger) were more accurate indices of degradation than were ratios involving total polyribsomes.
Abstract: Profiles of polyribosomes were obtained from etiolated stem segments of Pisum sativum L. var. Alaska isolated in various buffers. Tissue homogenized in a medium containing 0.2 m tris-HCl, pH 8.5, 0.2 m sucrose, 30 mm MgCl2, and 60 mm KCl yielded polyribosomes exhibiting far less degradation than tissue homogenized in conventional media containing tris-HCl at lower ionic strength and pH. A further decrease in degradation was found when polyribosomes were sedimented through a sucrose pad buffered at pH 8.5 prior to centrifugation. Increased separation was obtained using heavy (125-500 mg/ml), linear sucrose gradients. Using these techniques, messenger RNA species bearing up to 12 ribosomes (dodecamers) were resolved, with messenger RNA chains bearing 9 ribosomes (nonamers) being the most abundant (having the highest absorption peak). The data presented suggest that buffer of high ionic strength and high pH was more effective in preventing degradation of polyribosomes than was diethyl pyrocarbonate and, furthermore, that ratios involving large polyribosomes (hexamers and larger) were more accurate indices of degradation than were ratios involving total polyribosomes.
168 citations
TL;DR: Infectivity of the free-RNA exocortis virus from Gynura aurantiaca was maximal 40–60 days post-infection with the virus still recoverable after 140 days, suggesting the presence of a low molecular weight “tRNA-Like” or a RNA: DNA hybrid molecule for the infectious form of CEV.
127 citations
TL;DR: Resistance of the 8–16S moiety to inactivation by heat or diethylpyrocarbonate further suggests the presence of ds regions, and this model is consistent with the low sedimentation coefficient and the susceptibility to RNAase.
Abstract: THE anomalous properties of the infectious agent of exocortis disease in citrus (CEV), supposedly a virus, have been attributed1,2 to infectious RNA existing as free nucleic acid. Although this model is consistent with the low sedimentation coefficient and the susceptibility to RNAase, the infectious molecule does not cosediment with either single stranded (ss) or double stranded (ds) RNA markers after equilibrium sedimentation in Cs2SO4. Resistance of the 8–16S moiety to inactivation by heat or diethylpyrocarbonate further suggests the presence of ds regions3. A low molecular weight “infectious” RNA species, undetected in healthy tissue, has been implicated as the causal agent of exocortis disease.
124 citations
TL;DR: In this paper, a LFALFA roughage was treated with sodium hydroxide or peroxides and fed to lambs in digestion and metabolism trials to increase the dry matter digestibility of the roughage.
Abstract: Summary A LFALFA stems, corn cobs, whole corn plant and corn stalks were treated with sodium hydroxide or peroxides and fed to lambs in digestion and metabolism trials. The dry roughages were mixed with the chemicals and enough water to increase the moisture to 50%. The materials were fed after a 48-hr. reaction period or after ensiling. Four percent NaOH treatment increased the dry matter digestibility of alfalfa stems by 6.8 percentage units. Corn cob dry matter digestibility in- creased by 11.2 percentage units due to 4% NaOH treatment. In vitro DMD of whole corn plant increased 9.7 percentage units but in vivo 'organic matter digestibility increased by only 2.5 percentage units. In vitro DMD of corn stalks increased 12.8 and 19.5 per= centage units, respectively, with 3 and 5% NaOH treatment. In vivo organic matter di- gestibility of corn stalks increased 10.1 and 11.2 percentage units, respectively, for 3 and 5% NaOH treatment when fed supplemented only with urea, minerals and vitamins. The five percent NaOH treated stalks showed a 20.5 percentage unit increase in organic mat- ter digestibility compared to untreated stalks when both were fed in combination with ground alfalfa stems. These results indicate that poor quality roughages can be treated with 3 to 5% NaOH, the moist mixture after ensiling is consumed readily by lambs without further treatment, and that the dry matter digestibility is increased by sufficient magni- tude to potentially improve animal perfor- mance. Introduction Low quality roughages are inefficiently util- ized by ruminants because of high content and poor digestibility of the fibrous fractions. This poor digestibility is related to the extent of
109 citations
TL;DR: In this paper, the electronic spectrum of butadiene was analyzed using a gaussian basis of double zeta quality augmented by diffuse 3s and 3p functions, and good agreement was obtained with experimental details of this spectrum, both for π→π* and certain Rydberg transitions.
93 citations
TL;DR: The structure of an ornithine-containing lipid from Thiobacillus thiooxidans has been elucidated and it is indicated that the δ-amino group and the carboxyl group of Ornithine were free and that the extracted lipid existed as a zwitterion.
90 citations
80 citations
TL;DR: Three factors were resolved by DEAE-cellulose column chromatography of the crude reticulocyte ribosomal salt wash and stimulated poly r(U-G) directed methionine transfer from Met-tRNA f Met into the terminal positions of the synthesized polypeptides.
77 citations
TL;DR: In this paper, it was shown that the V-N Franck-Condon absorption maximum may differ significantly from the energy of the absorption maximum with which it is often equated, and in particular it is found in the case of theπ→π* singlet-singlet excitation of ethylene that the ΔE fixmee value overestimates the most probable vibrational transition energy (7.89 eV) by some 0.4 eV.
Abstract: Ab initio calculations for CH2 twisting and CC stretching vibrational wavefunctions and energy levels are reported for various electronic states of ethylene C2H4. Electronic transition moments between these states are also obtained to allow a calculation of the oscillator strengths for vibrational transitions involved in various electronic band systems; from this study it is concluded that thevertical electronic energy differenceΔE
e may differ significantly from the energy of the absorption maximumΔE
max with which it is often equated. In particular it is found in the case of theπ→π
* singlet-singlet excitation of ethylene that theΔE
e value overestimates the most probable vibrational transition energy (7.89 eV) by some 0.4 eV, thereby offering an explanation for the fact that previous attempts to predict the location of theV-N Franck-Condon absorption maximum have consistently obtained substantially higher results than the 7.66 eV value actually observed. Similar calculations for various Rydberg species and for theN-T transition are also found to obtain a quite consistent representation of the electronic spectrum of this system.
TL;DR: In this article, a first-order, second-degree, ordinary differential equation (Riccati's equation) was used to specify the ellipse of polarization of light passing through an anisotropic medium, and the solution χ(z,χ0) represents a trajectory in the complex plane which is traversed as the distance z is increased, starting from an initial polarization χ0 at z = 0.
Abstract: When a single complex variable χ is used to specify the ellipse of polarization of light passing through an anisotropic medium, a first-order, second-degree, ordinary differential equation (Riccati’s equation) governs the evolution of χ with distance along the direction of propagation. In this differential equation the properties of the medium are represented by the elements nij of its N-matrix, which was first introduced by Jones. Its solution χ(z,χ0) represents a trajectory in the complex plane which is traversed as the distance z is increased, starting from an initial polarization χ0 at z = 0. A stereographic projection onto a tangent sphere produces the corresponding trajectory in the more-familiar Poincare-sphere representation. The function χ(z,χ0) has been determined for propagation along (i) an arbitrary direction in a homogeneous anisotropic medium, and (ii) the helical axis of a cholesteric liquid crystal. The solution in the first case provides a unified law that leads to all the rules for the use of the Poincare sphere. For axial propagation in a cholesteric liquid crystal, it is found that two orthogonal polarizations are privileged in that the axes of their ellipses are forced to remain in alignment with the principal axes of birefringence of the molecular planes. The general solution (that satisfies the conditions of propagation) shows that the ellipse of polarization never repeats itself. As to the two parameters of the ellipse, the ellipticity is shown to be periodic with periodicity shorter than the pitch of the helical structure and the azimuth is aperiodic.
TL;DR: In this article, the delta-ray theory of track structure is applied to such 1-or-more hit detection systems as the inactivation of dry enzymes and viruses, the NaI(Tl) scintillation counter, and nuclear emulsion, is extended to the silver activated phosphate glass dosimeter, the LiF thermoluminiscent dosimeter and the creation of free radicals in solid biological substances.
TL;DR: In this paper, the polarization properties of diffracted orders from a grating are determined ellipsometrically by examining the polarization of the specularly reflected zeroth-order beam at large angles of incidence.
Abstract: The polarization properties of the various diffracted orders from a grating are determined ellipsometrically. The ratio ${\ensuremath{\rho}}_{m}$ of the far-field complex reflection coefficients for the $p$ and $s$ polarizations for any order $m$ is measured. This information is complementary to the data available from the partition of the scattered energy over the radiating orders. By examining the polarization of the specularly reflected zeroth-order beam at large angles of incidence the optical effect of surface roughness is established. The roughened surface layer is shown to be equivalent to a film whose index of refraction is the average of the indices of the material of the surface and the immersion medium, in accordance with the Maxwell Garnett theory. The film thickness is a measure of the surface roughness. To explain the ellipsometric results on the various orders we derived an expression for ${\ensuremath{\rho}}_{m}$ starting from the Stratton-Silver-Chu integral using the physical-optics approximation. There is agreement between the gross features of the theory and experiment, but the exact magnitudes could not be compared. This points to the need for an exact solution of the grating-diffraction problem for both polarizations, including the effect of a finite conductivity at optical frequencies.
TL;DR: In this article, the polarization states of light incident on and emerging from an optical system are represented by complex numbers χ¯ and ξ¯, respectively, in two different planes.
Abstract: The polarization states of light incident on and emerging from an optical system are represented by complex numbers χ¯ and ξ¯, respectively, in two different planes. In this representation, the input–output transfer function ξ¯=f(χ¯) is a conformal bilinear transformation with coefficients given by the elements of the system’s Jones matrix. From the known properties of the bilinear transformation, important conclusions can be reached on the response of optical systems to incident light of all possible polarization forms. In addition, the analysis appears to have considerable potential in the synthesis of systems to effect a prescribed polarization transfer. As an example, the ellipsometer is analyzed by use of some of the ideas developed.
TL;DR: The induction of glucoamylase by maltose was independent of sulfate concentration but showed a dependency on low pH and the absence of utilizable carbon sources.
Abstract: Low levels of glucoamylase are produced when Aspergillus niger is grown on sorbitol, but substitution of the latter by glucose, maltose, or starch results in greater formation of glucoamylase as measured by enzymatic activity. Both glucoamylase I and glucoamylase II are formed in a yeast extract medium; however, glucoamylase I appears to be the only form produced when ammonium chloride is the nitrogen source. Maltose or isomaltose (1.4 × 10−4m), but no other disaccharides or monosaccharides, dextrins, dextrans, or starches, stimulated glucoamylase formation when added to mycelia pregrown on sorbitol-ammonium salts. The induction of glucoamylase by maltose was independent of sulfate concentration but showed a dependency on low pH and the absence of utilizable carbon sources.
TL;DR: In this paper, the problem of measuring branching ratios or transition probabilities using the technique of photoelectron spectroscopy in terms of the angular distribution of the ejected photoelectrons was discussed.
Abstract: Discussion of the problem of measuring branching ratios or transition probabilities using the technique of photoelectron spectroscopy in terms of the angular distribution of the ejected photoelectrons. Equations are developed that can be used in conjunction with any type of electron-energy analyzer to correct for any discrimination in the analyzer caused by electrons of varying angular distribution. Results are presented for the branching ratios of the A super 2 pi sub u and B super 2 sigma sub u (+) states of CO2(+) produced by 584 A and obtained by a variety of electron-energy analyzers.
TL;DR: Glycine entry by the main Na + -dependent route absolutely requires an anion as cofactor, but some anions allow a little glycine entry in the absence, but not the presence of the ASC amino acid transport inhibitor, alanine, which suggests that the ASC route of Christensen either has a lower anion specificity than the main glycine route or lacks an anions requirement.
TL;DR: In this article, a sequence of observations is obtained; each observation is known to be a value on one of two distinct absolutely continuous p-dimensional random variables, X and Y. The problem is to decide whether each observation are on X or Y. Some discrimination procedures are suggested and, using Monte Carlo methods, they are compared with other discrimination procedures to be found in the literature.
Abstract: A sequence of observations is obtained; each observation is known to be a value on one of two distinct absolutely continuous p-dimensional random variables, X and Y. The problem is to decide whether each observation is on X or Y. Some discrimination procedures are suggested and, using Monte Carlo methods, they are compared with other discrimination procedures to be found in the literature. The overall best performer in the comparisons of this study is one of the suggested procedures, a “nearest neighbor” type procedure based on statistically equivalent blocks.
TL;DR: In this paper, various ab initio CI treatments are reported for the 3 Σ − g, 1 Δ g and 1 Σ + g states of O 2 with particular emphasis on the agreement obtained between calculated and experimental results for binding energies and bond distances of these species and also for transition energies between them.
TL;DR: The early Pleistocene changes in fluvial sediments suggest modification in degradational energy affecting detritus apparently related to deterioration of climate in the early Pliocene as discussed by the authors.
Abstract: The change from Pliocene to Pleistocene fluvial sedimentation in Nebraska is denoted by gravel with relative enrichment of mechanically weak rock species and a two-fold increase in largest clast size. These changes in fluvial sediments suggest modification in degradational energy affecting detritus apparently related to deterioration of climate in the early Pleistocene. Cooler Pleistocene climates with increased moisture resulted in greater discharge and carrying capacity for streams headed in the Rocky Mountains and flowing across Nebraska. These streams carried granitic detritus eastward toward the continental glacier margin in easternmost Nebraska. There, streams flowing off ice sheets carrying sedimentary and metamorphic detritus derived from the ice joined the east-flowing streams from the mountains. Detritus derived from continental glaciers in easternmost Nebraska, therefore, was not transported westward, but instead, was mixed with Rocky Mountain–derived detritus and transported southward along the ice-front margin.
Even though the drainage basin of the Platte River system came into existence in the Tertiary, the present course of the Platte River dates only from mid-Pleistocene time. Widespread occurrence of lower Pleistocene braided channel deposits east of the Chadron–Cambridge Arch that contain Laramie Range–derived anorthosite indicates repeated channel switching and meandering during times of aggradation over surfaces of minimal relief. Relations of these gravels to the Chadron–Cambridge and Siouxana Arches suggest that uplift on these structures was sufficient to deflect and control the course of streams headed in the Laramie Range and flowing across the plains. Activity on the Chadron–Cambridge Arch also is suggested by the distribution of earthquake epicenters, modern drainage patterns, and the relation of the pre-Pleistocene bedrock surface to the arch and the profile of the Platte River. The presence of knickpoints on rivers crossing the arch suggests that these rivers are maintaining a course antecedent to a spasmodically rising arch. Rivers are entrenched now, but during the early Pleistocene when streams carried a heavy load of sand and gravel, similar activity along the Chadron–Cambridge Arch would have been adequate to spill the aggrading stream over its fan and divert it southward where it could follow a new course. Eastward-flowing streams heading in the Rocky Mountains were controlled by changes in discharge of streams and movement on epeirogenic structures during the early Pleistocene.
TL;DR: The midsphenoidal synchondrosis seems to be the primary factor in the mode of flexure of the cranial base in Macaques, and its delayed fusion in nonhuman primates when compared to man.
Abstract: The contribution of the basicranial synchondroses in the growth of neurocranial length and ontogenetic development of the cranial base were investigated. The study concentrated on the midsphenoidal synchondrosis and its delayed fusion in nonhuman primates when compared to man, and on the spheno-occipital synchondrosis. The mode and time of fusion of both growth centers were observed, and their role in the ontogenetic growth changes (flattening processes) of the cranial base were established. The chondrogenic ossification of midsphenoidal and spheno-occipital synchondroses was studied on 20 skulls of Macaca mulatta females, ranging in age from newborn specimens to those 24 months old. The technique of in vivo tetracycline bone labeling was used for histologic evaluation of the material. Different chondrogenic growth patterns were observed in both synchondroses. The endochondral activity of the spheno-occipital synchondrosis increased with age, from a nonactive narrow cartilaginous column in the neonatal specimen to a broad band with high chondrogenic ossification in the 24-month-old specimens. This growth center contributes to elongation of the posterior portion of the cranial base and is a secondary factor in its flexion.
The midsphenoidal synchondrosis seems to be the primary factor in the mode of flexure of the cranial base in Macaques. This growth center is very active in the first ten months of life but later exhibits cessation of chondrogenic activity and long remains unfused. The first signs of fusion were observed as late as 72 months of age. At the same time, the continuous process of cranial base flattening showed the first signs of tapering off.
TL;DR: In this article, the polarization transfer function of any optical system is determined using conventional ellipsometry, where only three null measurements are needed to determine the three complex parameters that define the transfer function.
Abstract: Conventional ellipsometry is extended to determine the polarization transfer function of any optical system. Only three null measurements are needed to determine the three complex parameters that define the transfer function. More measurements can be taken to overdetermine the unknown parameters, to reduce the effect of the various sources of error in the ellipsometer. The conditons for compensation (the existence of a null) are defined. A system composed of a retardation plate and a mirror is measured to demonstrate the various aspects of the theory and to illustrate the application of the method. This technique makes it possible to characterize surfaces that exhibit anomalous cross-scattering effects.
01 Oct 1972
TL;DR: An attempt is made to identify among the welter of "promising" results areas of tangible achievement as well as likely bottlenecks, and to assess the contribution to be expected of digital image-processing methods in both operational and experimental utilization of the forthcoming torrent of data.
Abstract: The United States space program is in the throes of a major shift in emphasis from exploration of the moon and nearby planets to the application of remote sensing technology toward increased scientific understanding and economic exploitation of the earth itself. Over one hundred potential applications have already been identified. Since data from the unmanned Earth Resources Technology Satellites and the manned Earth Resources Observation Satellites are not yet available, the experimentation required to realize the ambitious goals of these projects is carried out through approximation of the expected characteristics of the data by means of images derived from weather satellite vidicon and spin-scan cameras, Gemini and Apollo photographs, and the comprehensive sensor complement of the NASA earth resources observation aircraft. The extensive and varied work currently underway is reviewed in terms of the special purpose scan and display equipment and efficient data manipulation routines required for high-resolution images; the essential role of interactive processing; the application of supervised classification methods to crop and timber forecasts, geological exploration, and hydrological surveys; the need for nonsupervised classification techniques for video compaction and for more efficient utilization of ground-control samples; and the outstanding problem of mapping accurately the collected data on a standard coordinate system. An attempt is made to identify among the welter of "promising" results areas of tangible achievement as well as likely bottlenecks, and to assess the contribution to be expected of digital image-processing methods in both operational and experimental utilization of the forthcoming torrent of data.
TL;DR: In this article, the authors characterized lattice damage in silicon induced by low-energy argon ions is characterized ellipsometrically in two ways: optical model consisting of residual surface contamination and the partially-damaged substrate.
TL;DR: The authors found that anticipating arousal symptoms (rather than benign) from a placebo pill reduced inhibiting emotion in men, resulting in more cheating, while the effect did not occur for women.
TL;DR: In this article, the effect of dry oven heating on the nutritive value of soybeans was investigated and a rapid inactivation of the growth inhibition effect in whole dry beans was observed yielding a product with little browning.
Abstract: HEAT TREATMENT of soybeans to inactivate intrinsic growth inhibitors has been limited to a temperature times pressure times moisture interaction (Osborne and Mendel, 19 17; Hayward et al., 1936). Presumably, the pressure effect increases the possible temperature while moisture is necessary to mediate some as yet unidentified biochemical reaction accomplishing inactivation of the growth inhibitor. Dry oven heating was noted by Osborne and Mendel (1917) to be quite ineffective in improving the nutritive value of soybeans; an observation supported by recent unpublished data in our laboratory, even after increasing the initial moisture content of the beans to 30%. In conjunction with studies of radiofrequency (RF) dielectric heating on a variety of agricultural and related products, we have investigated the effect of this type of energy on the nutritive value of soybeans. A rapid inactivation of the growth inhibition effect in whole dry beans was observed yielding a product with little browning.
TL;DR: In this article, the standard enthalpy of solution of gaseous ammonia in water to form the nonionized solute was found to be ΔHsolno(298.15 K) = − (8448 ± 15) calth mol−1 by direct solution calorimetry.