Showing papers by "Texas A&M University published in 1973"
27 Nov 1973
TL;DR: In this article, a resource and land use classification system was developed which uses available soil survey information and interpretations from NASA obtained high flight aerial photography to locate discrete areas of similar rangeland vegetation.
Abstract: The author has identified the following significant results. Emphasis has been given to an inventory of land resource types and land use at the ten Great Plains Corridor test sites. A resource and land use classification system was developed which uses available soil survey information and interpretations from NASA obtained high flight aerial photography to locate discrete areas of similar rangeland vegetation. Existing classification systems, even those developed for use with remote sensor data, were found to be inadequate for this project. This system is expected to be of general use for remote sensing related to land use and management. It has specific applicability to any effort aimed at regional use of ERTS-1 MSS digital data products. A preliminary assessment of the relative importance of rangelands in the Great Plains Corridor states indicates that the value of the livestock industry supported by this resource exceeds 23 billion dollars. The development of a Rangeland Feed Conditions index for this region could be used by more than 400,000 farm and ranch operators involved in the production of more than 40% of the nation's beef and much of the country's grain.
1,017 citations
1,017 citations
347 citations
TL;DR: In this article, a modified version of Kick's Law is used to obtain Knoop hardness numbers independent of the applied load, which is applied to nine specimens of varient hardness and proven valid by graphical methods.
329 citations
TL;DR: The spectral data indicate that only 5 to 25% of the iron becomes bound when 1 eq of FeCl3 is added to apotransferrin at neutral pH, and the remaining sites of the protein are vacant and available for reaction with Fe3+-nitrilotriacetic acid.
312 citations
TL;DR: The matrix operator approach contains the doubling method as a special case and numerous curves are given for both the reflected and transmitted radiance for Rayleigh scattering from a homogeneous layer.
Abstract: An entirely rigorous method for the solution of the equations for radiative transfer based on the matrix operator theory is reviewed. The advantages of the present method are: (1) all orders of the reflection and transmission matrices are calculated at once; (2) layers of any thickness may be combined, so that a realistic model of the atmosphere can be developed from any arbitrary number of layers, each with different properties and thicknesses; (3) calculations can readily be made for large optical depths and with highly anisotropic phase functions; (4) results are obtained for any desired value of the surface albedo including the value unity and for a large number of polar and azimuthal angles; (5) all fundamental equations can be interpreted immediately in terms of the physical interactions appropriate to the problem; and (6) both upward and downward radiance can be calculated at interior points from relatively simple expressions.
288 citations
226 citations
TL;DR: The ultrastructure of Peridinium balticum indicates that an eudosymbiont is present within the dinoflagellate, and the origin of photosynthetic dinofLagellates from heterotrophic forms by means of a chrysophyte‐like endosymbIONt is postulated.
Abstract: SUMMARY
The ultrastructure of Peridinium balticum indicates that an eudosymbiont is present within the dinoflagellate. The structure and probable function of the organelles of both protists arc described and discussed. The origin of photosynthetic dinoflagellates from heterotrophic forms by means of a chrysophyte-like endosymbiont is postulated.
193 citations
Johns Hopkins University1, California Institute of Technology2, Carnegie Mellon University3, University of California4, Goddard Space Flight Center5, Ames Research Center6, Centre national de la recherche scientifique7, National Research Council8, University of Washington9, Texas A&M University10, University of Colorado Boulder11, Oregon State University12, Smithsonian Astrophysical Observatory13
TL;DR: The strength of the K line of singly ionized calcium has been measured for several hundred A-type stars within a few hundred parsecs of the Sun and for the A stars in several galactic star clusters as mentioned in this paper.
Abstract: The strength of the K line of singly ionized calcium has been measured for several hundred A-type stars within a few hundred parsecs of the Sun and for the A stars in several galactic star clusters. The derived abundance of calcium varies from star to star by up to a factor of 2, and there is no correlation of abundance with the space motion of the stars.
177 citations
TL;DR: The crystal structure and low temperature PMR spectra of the diironhexacarbonyl adduct of bicyclo[6.2]deca-1,3,5-triene have been determined as mentioned in this paper.
167 citations
TL;DR: In this paper, the specific Cu+CO interaction was revealed by a strong infrared absorption band at 2160 cm− and a heat of adsorption of 14.7 kcal/mole.
TL;DR: Data are consistent with the conclusion that the small enrichment of (12)C in the carbon atoms of malate and glucose (with respect to atmospheric CO(2)) in leaves of Sorghum bicolor, Haygrazer occurs at the phosphoenolpyruvate carboxylase step.
Abstract: The carbon atoms of glucose and malate in C4 plants are 2 to 3‰ enriched in 12C with respect to atmospheric CO2; whereas these intermediates in C3 plants are 15 to 18‰ enriched with 12C with respect to atmospheric CO2. The enzymatic synthesis of malate from phosphoenolpyruvate and bicarbonate in preparations of leaves of Sorghum bicolor, Haygrazer result in a carbon isotope fractionation of about 3‰. The enzymatic synthesis of phosphoglyceric acid from ribulose 1,5-diP and CO2 in these preparations (contaminated with carbonic anhydrase) at 24 C and 37 C result in a carbon isotope fractionation of 33.7‰ and 18.3‰, respectively. These data are consistent with the conclusion that the small enrichment of 12C in the carbon atoms of malate and glucose (with respect to atmospheric CO2) in leaves of Sorghum bicolor, Haygrazer occurs at the phosphoenolpyruvate carboxylase step.
TL;DR: In this article, the binary-encounter approximation (BEA) is transformed from momentum space to configuration space, and the impact-parameter representation allows one to calculate a variety of quantities pertinent to the general problem of ionization.
Abstract: The binary-encounter approximation (BEA) is transformed from momentum space to configuration space. In this frame the impact-parameter representation allows one to calculate a variety of quantities pertinent to the general problem of ionization. Among these are cross sections for proton ionization of hydrogen and helium; in the latter case, croas sections for ejection of both electrons are also given. A number of tables and formulas are given, enabling one to correct the simple hydrogenlike-model predictions of the BEA for effects which arise in multielectron atoms. Multiple-ionization probabilities (K + L shell) are calculated and compared to experimental results and to the predictions of the semiclassical approximation.
TL;DR: In this article, the carbon isotope composition of the particulate matter from the cold polar surface waters was lighter ( −24·7 to −26·0‰ ) than that from the surface in the semi-tropical regions ( −19·8 to −22·3 ‰ ), reflecting the temperature effect on the photosynthetic fixation of carbon.
TL;DR: In this article, the authors report a test of consumer demand theory using price, quantity and expenditure data for individual consumer's entire expenditures in an ongoing economic system, and the analysis presented below demonstrates that efforts directed along these lines are essential to obtain observations of sufficient accuracy to contradict consumer demand and distinguish between actual contradictions between propositions of the theory and propositions describing observations.
Abstract: In this paper we report a test of consumer demand theory using price, quantity and expenditure data for individual consumer's entire expenditures in an ongoing economic system. In conducting the test major emphasis has been placed on controlling and calculating errors of observation in the data collected and explicitly incorporating the measures of errors of observation into the evaluation of the test results.) The analysis presented below demonstrates that efforts directed along these lines are essential to (I) obtain observations of sufficient accuracy to contradict the theory of consumer demand and (2) distinguish between actual contradictions between propositions of the theory and propositions describing observations, on the one hand, and the effects of measurement error, on the other. 0
TL;DR: Uranium concentrations in a large number of marine sediment samples of different types with world-wide spatial distribution have been determined using the rapid, precise and nondestructive technique of counting the delayed neutrons emitted during U 235 fission induced with thermal neutrons as mentioned in this paper.
TL;DR: A mechanical analysis of the cellular deformations which occur during the opening and closing of stomata is presented, showing how the shape, size, wall thickness and material properties of the guard cell walls influence their behavior.
TL;DR: In this article, blood protein concentrates were prepared from the serum and decolorized hemoglobin fractions of bovine blood, and the emulsifying capacity of the concentrates was dependent on protein concentration and was not affected by spray drying.
Abstract: Blood protein concentrates were prepared from the serum and decolorized hemoglobin fractions of bovine blood. The emulsifying capacity of the concentrates was dependent on protein concentration and was not affected by spray drying. However, when the serum protein fraction was subjected to the decolorization treatment, its emulsifying capacity was reduced. Lactose, when added to the serum proteins prior to spray drying, prevented this reduction.
TL;DR: The object of the present communication is to examine the primary sources which have led to the saturated diet fat concept (as distinct from diet cholesterol) in light of the authors' present knowledge, and against criteria of acceptable scientific demonstration.
TL;DR: In this paper, the porometer measurements of stomatal resistance were used to evaluate the response of a sorghum crop to changes in solar radiation, S, and soil water potential, and showed that doubling crop density of the present practice and irrigating to maintain stromatal resistances near minimum may increase yields by about 100%, whereas evaporation by only 33%, significantly improving the efficiency of water use.
TL;DR: In this paper, the cross section for K-shell ionization derived from experimental measurements with the light ions 1H, 2H, 3He, and 4He are tabulated according to projectile energy and target atomic number.
TL;DR: The nature of early life, chemical relationships, and the number of protenogenic amino acids in early life are reviewed.
Abstract: IV. A new approach to the problem ............................................................... 304 A. The nature of the genetic code ....................................................... 305 B. Chemical relationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311 C. The proposed metabolic model ....................................................... 313 D. Evolution of the basic series (Group I) .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314 E. Evolution of the first derived series (Group II) .............................. 318 F. Development of the second derived series (Group III) .. . . . . . . . . . . . . . . . . 319 G. Evolutionary history of the final series (Group IV) ...................... 321 V. Discussion ........................................................................................... 324 A. Evidence pertaining to the amino acids ............................................. 325 B. Evidence from transfer RNA ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326 C. The four groups in retrospect ......................................................... 330 D. The nature of early life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332 E. The number of protenogenic amino acids .......................................... 333 VI. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335 VII. References cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338
TL;DR: In this paper, the degree and direction of polarization, the ellipticity, and the radiance of the radiation at various levels in the atmosphere and ocean are calculated by a Monte Carlo method which includes all orders of multiple scattering.
Abstract: The degree and direction of polarization, the ellipticity, and the radiance of the radiation at various levels in the atmosphere and ocean are calculated by a Monte Carlo method which includes all orders of multiple scattering. Both Rayleigh scattering by the molecules and Mie scattering by the aerosols, as well as molecular and aerosol absorption, are included in the model of the atmosphere. Similarly, in the ocean, both Rayleigh scattering by the water molecules and Mie scattering by the hydrosols, as well as absorption by the water molecules and hydrosols, are considered. Separate single-scattering phase matrices are calculated from Mie theory for the aerosols and hydrosols. Both the reflected and refracted rays, as well as the rays that undergo total internal reflection, are followed from the ocean surface which is assumed to be flat. The degree and direction of polarization, the ellipticity, the radiance and the flux are given as functions of the turbidity of the ocean, the solar zenith angl...
TL;DR: Reduced pressure, which reduced the internal levels of ethylene, delayed abscission of young fruits and leaves, supported the conclusion from this study- that ethylene is one of the regulators of young fruit abscissions in cotton.
Abstract: In an earlier study we reported that detached cotton flowers produced sufficient ethylene before the period of natural abscission to suggest that ethylene might be a natural regulator of young fruit abscission. The present report explores this probability further. Intact cotton (Gossypium hirsutum L.) fruits produced ethylene at rates as high as 36 μl ethylene/kg fresh wt·hr during the 2 days before they abscised. Direct measurements of ethylene in gas samples withdrawn from fruits indicated that production of 1 μl ethylene/kg fresh wt·hr is equivalent to an internal concentration of approximately 0.1 μl/l. Fumigation of fruiting cotton plants with only 0.5 μl/l caused 100% abscission of young fruits and floral buds within 2 days. This correlated with the estimated endogenous levels of ethylene. Reduced pressure, which reduced the internal levels of ethylene, delayed abscission of young fruits and leaves, a result which supports our conclusion from this study— that ethylene is one of the regulators of young fruit abscission in cotton.
TL;DR: In this article, the power invariant, nonlinear differential equations that describe the behavior of a two-phase equivalent of a balanced three-phase induction motor, are linearized about an arbitrary nominal point.
Abstract: The power invariant, nonlinear differential equations, that describe the behavior of a two-phase equivalent of a balanced three-phase induction motor, are linearized about an arbitrary nominal point. Under the assumption that terminal voltage and system frequency can be approximated by a straight line segment over any interval of time, solutions of these small perturbation equations are used to give expressions for active and reactive power delivered tb the motor during transient conditions. These newly developed expressions for power, which turn out to be implicit functions of voltage and frequency, and explicit functions of time and the rates of change of voltage and frequency, are proposed as a load model represeptation of an induction motor for use in transient stability studies. An intuitively appealing, corrective technique, which reduces the error introduced by the use of a linearized model, is presented. Eigenvalues of the linearized system of equations for a group of typical induction motors are given. For a small low voltage motor, a sensitivity study of the dominant eigenvalue to changes in nominal point quantities and parameters is made. Values of active and reactive power calculated by a numericzal solution of the motor nonlinear differential equations are compared with those values of power predicted by the model for certain specific rates of change of voltage and frequency.
TL;DR: In this paper, the authors present an assessment of the solution procedures available for the analysis of inelastic and/or large deflection structural behavior, and compare and evaluate each with respect to computational accuracy, economy, and efficiency.
Abstract: This paper presents an assessment of the solution procedures available for the analysis of inelastic and/or large deflection structural behavior. A literature survey is given which summarizes the contribution of other researchers in the analysis of structural problems exhibiting material nonlinearities and combined geometric-material nonlinearities. Attention is focused at evaluating the available computational and solution techniques. Each of the solution techniques is developed from a common equation of equilibrium in terms of pseudo forces. The solution procedures are applied to circular plates and shells of revolution in an attempt to compare and evaluate each with respect to computational accuracy, economy, and efficiency. Based on the numerical studies, observations and comments are made with regard to the accuracy and economy of each solution technique.
TL;DR: The concluding section of the paper compares the types of methods, discusses their suitabihty for different types of processing, and makes suggestions about the adaptability and flexibility of the maj or exmting methods of indexing algorithms for application to user problems.
Abstract: Indexing schemes of main interest are the bit map, address map, row-column, and the threaded list Major variations of the indexing techniques above mentioned are noted, as well as the particular indexing scheme inherent in diagonal or band matrices. The concluding section of the paper compares the types of methods, discusses their suitabihty for different types of processing, and makes suggestions eoneernlng the adaptability and flexibility of the maj or exmting methods of indexing algorithms for application to user problems
TL;DR: In this article, a flight test program has been conducted to measure experimentally parameters which describe the characteristics of vortex behavior and their instability, and experimental results show wavelengths of vortex instabilities, dissipation time of trailing vortices, effects of atmospheric current or gust, and the effect of control surface oscillation.
Abstract: A flight test program has been conducted to measure experimentally parameters which describe the characteristics of vortex behavior and their instability. Three basic atmospheric flight conditions were investigated: steady level flight in calm air, steady level flight in light gusting air and light winds, and unsteady flight produced by control surface oscillations in calm air. A DeHavilland Beaver DHC-2 airplane and a Beechcraft T-34B airplane were used in the investigation. Smoke grenades were located near the wing tips of each airplane such that the vortices could be seeded with smoke and thus made visible. This made it possible to photograph the vortices and make measurements from the photographs obtained. The experimental results show wavelengths of vortex instabilities, dissipation time of trailing vortices, effects of atmospheric current or gust, and the effect of control surface oscillation. These results provide additional experimental verification of the existence of vortex wake instability predicted by theory and show that small oscillations in pitch at a critical frequency accelerate the dissipation of high-intensity vortices.