Showing papers by "Iowa State University published in 1982"
TL;DR: In this paper, a low-air-density wind tunnel was used to extend the range of previous investigations and to separate the effects of Reynolds number and interparticle forces of cohesion.
Abstract: New formulations valid for wide ranges of particle diameter and density and gas density are presented for prediction of saltation threshold speed for small particles. A low-air-density wind tunnel was used to extend the range of previous investigations and to separate the effects of Reynolds number and interparticle forces of cohesion. The new formulations are used to predict saltation threshold for atmospheric conditions on the surface of the Earth, Mars, and Venus.
488 citations
TL;DR: In this paper, the authors considered the construction of sample designs and estimators under a linear regression superpopulation model and used the anticipated variance, the variance of the predictor computed with respect to the sampling design and the super population model, as a criterion for evaluating probability designs and model-unbiased predictors.
Abstract: The construction of sample designs and estimators under a linear regression superpopulation model is considered. The anticipated variance, the variance of the predictor computed with respect to the sampling design and the superpopulation model, is used as a criterion for evaluating probability designs and model-unbiased predictors. Regression predictors that are model unbiased and design consistent are constructed.
453 citations
TL;DR: The present investigation support the idea that the repetitive loading resulting from gait generates intermittent waves that propagate through the entire human musculoskeletal system from the heel up to the head, and that the human locomotor system tries to prevent overloading of the head from insufficiently attenuated shock waves.
270 citations
TL;DR: An improvement over existing procedures for the determination of nanomole quantities of inorganic phosphate (Pi) is described, and the effective concentration range of Pi in which the assay may be used is increased.
230 citations
211 citations
TL;DR: In this article, the advantages and limitations of the commonly used linear and curvilinear D/Do = a(S−b) and KSm-based diffusion equations are considered and a new diffusion equation is proposed to combine the advantages of the previous equations.
208 citations
TL;DR: The impact of the introduction of a computer-based information system on the system users' level of information satisfaction and job satisfaction was investigated and both types of satisfaction increased.
Abstract: The impact of the introduction of a computer-based information system on the system users' level of information satisfaction and job satisfaction was investigated. Both types of satisfaction increa...
205 citations
TL;DR: In this paper, Measuring Environmental Concern: The New Environmental Paradigm Scale is proposed as a scale for measuring environmental concern. The Journal of Environmental Education: Vol. 13, No. 3, pp. 39-43.
Abstract: (1982). Measuring Environmental Concern: The New Environmental Paradigm Scale. The Journal of Environmental Education: Vol. 13, No. 3, pp. 39-43.
194 citations
TL;DR: This paper aims to demonstrate the efforts towards in-situ applicability of EMMARM, as to provide real-time information about the response of the immune system to antibiotics.
Abstract: 1 Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois 60115 z Houghton Poultry Research Station, Huntingdon, Cambs PE17 2DA, United Kingdom 3 The Wistar Institute, Thirty-Sixth Street at Spruce, Philadelphia, Pennsylvania 19104 4 Department of Microbiology, New York University School of Medicine, 550 First Avenue, New York, New York 10016 5 College de France, Laboratoire de M6dicine Exp6rimentale, 11, Place Marcelin-Berthelot, 75231 Paris, Cedex 05, France 6 Institute for General and Experimental Pathology, University of Innsbruck, Fritz-Pregl-Strasse 3, A-6020 Innsbruck, Austria 7 Institute for Experimental Immunology, University of Copenhagen, N0rre Alle 71, DK-2100 Copenhagen 0, Denmark s Department of Immunology and MRC Group of Immunoregulation, University of Alberta, Edmonton, Alberta, Canada 9 Department of Animal Science, Iowa State University, Ames, Iowa 50011 10 Basel Institute for Immunology, Grenzacherstrasse 487, CH-4005 Basel, Switzerland ~1 Department of Avian Medicine, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30605 a Department of Medical Microbiology, Turku University, Turku, Finland 20520
186 citations
TL;DR: The results show that supplemental fat increased transit time of ingesta in chickens, which may be helpful in understanding the nature of the extrametabolic effect of fat in poultry diets.
TL;DR: The glucans were identified by physical appearance, the concentration of ethanol required for precipitation, periodate-oxidation behavior, and susceptibility to hydrolysis by endodextranase.
TL;DR: Responses of dorsal horn neurons to bath application of substance P, somatostatin and enkephalin were studied by intracellular recording in the neonatal spinal cord slice preparation and the depolarization was most commonly associated with an increase in neuronal input resistance.
TL;DR: Tabulation of α, the intercept values of rectilinear body-scale regressions used in Fraser-Lee calculation of growth from scales, for several species of centrarchids and percids showed wide variation from population to population.
Abstract: Tabulation of α, the intercept values of rectilinear body-scale regressions used in Fraser-Lee calculation of growth from scales, for several species of centrarchids and percids showed wide variation from population to population. This variation is believed to be less the result of actual differences among populations than the result of measuring scales at different angles, collecting scales from different areas of the body, season of collection, and samples with poor representation of all sizes. Use of standard α values for each species would eliminate the variance caused by poor sampling. The following standards are proposed for all studies in which there is question of adequate sampling for body-scale regressions: 10 mm, Lepomis cyanellus; 20 mm, Ambloplites rupestris, L. gulosus, L. macrochirus, Micropterus salmoides; 25 mm, L. gibbosus; 30 mm, Perca flavescens; 35 mm, M. dolomieui, Pomoxis annularis, Pomoxix nigromaculatus; 55 mm, Stizostedion vitreum. Collection of scales for these species ...
TL;DR: In this article, the minimal basis set (in molecule-adapted form) is defined as a theoretically sound concept for the understanding of accurate molecular wavefunctions, and a new localization procedure is formulated which yields atom-adaptive molecular orbitals.
TL;DR: There was little or no malabsorption measured by the uptake of D-xylose and the fact that infection of both the crypt and villus epithelial cells was observed, suggests that the pathogenesis may be different from rotavirus and coronavirus.
TL;DR: If one accepts that the estrogen:progesterone ratio controls UBF through alterations in the function of periarterial adrenergic nerves, the impaired function of the nerves during mid and late gestation may preclude the effects of these steroids.
Abstract: Current investigations strongly indicate a relationship between the function of adrenergic (vasoconstrictor) nerves innervating uterine and ovarian arteries and local concentrations of estrogen and progesterone. During the estrous cycle of ewes, cows and sows, the higher the estrogen:progesterone ratio in systemic blood, the greater is the quantity of blood flowing through the uterine vascular bed. When converted to a catechol form, estrogen may reduce uterine vasoconstriction by binding to and suppressing perivascular alpha-adrenergic receptor activity. Progesterone, in contrast to estrogen, augments the responsiveness of vascular smooth muscle to norepinephrine. Lymphatic vessels, which are in close linear apposition to the adventitia of the uterine vasculature may serve to transport steroids to the periarterial nerves. Vasodilation associated with steroid-induced changes in autonomic function appears to be modulated and amplified by estrogen-dependent changes in prostaglandin biosynthesis. During early pregnancy in ewes, cows and sows, vasodilation, mediated by the conceptus, occurs in the luteal and (or) uterine vascular beds on days critical for continuation of pregnancy in each species. In cows and sows, this vasodilatory effect of the conceptus is associated with increased concentrations of estrogens in the uterine lumen, as well as the lymph and blood draining the uterus. After the initial increase in blood flow to the uterus during early pregnancy, changes in the estrogen:progesterone ratio in fetal and maternal fluids appear to be unrelated to changes in uterine blood flow (UBF). This lack of association between the estrogen:progesterone ratio and UBF may result from a progressive reduction in number of adrenergic nerves observed in the uterus throughout pregnancy. If one accepts that the estrogen:progesterone ratio controls UBF through alterations in the function of periarterial adrenergic nerves, the impaired function of the nerves during mid and late gestation may preclude the effects of these steroids.
TL;DR: It is shown that the class of all sets which are both P-selective and have positive reductions to their complements is P, and it follows that various naturally defined apparently intractible problems are not p- selective unless P = NP.
TL;DR: In this article, a new method for detecting changes in the power system frequency, by relating it to a leakage coefficient in the FFT, is presented, and the algorithm computes the deviation of the system frequency from the fundamental component and the best estimate of its rate of change, and finally trips the appropriate amounts of load at the appropriate time delays.
Abstract: A power system disturbance, or operating abnormality, can produce a severe generation and load imbalance, resulting in a rapid frequency decline. The possibility of such a disturbance has led to increased interest in the application of automatic under-frequency protection schemes to restore load/generation balance and to prevent equipment damage. In this paper a new method for detecting changes in the power system frequency, by relating it to a leakage coefficient in the FFT, is presented. The algorithm computes the deviation of the power system frequency from the fundamental component and the best estimate of its rate of change. The algorithm then predicts the percentage generation and load imbalance, and finally trips the appropriate amounts of load at the appropriate time delays.
TL;DR: In this article, the efficiencies and capacities of diol-bonded silica packings of pore size 60-4000 A were examined, where Glucosamine was bonded to the diol phase and affinity chromatographic separations of concanavalin A and bovine serum albumin were performed.
TL;DR: In this article, the authors considered the energy dissipation associated with flux-line cutting (intersection and cross-joining of adjacent nonparallel vortices) and proposed a critical-state model to calculate predicted hysteretic ac fluxline-cutting losses in type-II superconductors.
Abstract: Energy dissipation associated with flux-line cutting (intersection and cross-joining of adjacent nonparallel vortices) is considered theoretically. The flux-line-cutting contribution to the dissipation per unit volume, arising from mutual annihilation of transverse magnetic flux, is identified as ${\stackrel{\ensuremath{\rightarrow}}{\mathrm{J}}}_{\ensuremath{\parallel}}\ifmmode\cdot\else\textperiodcentered\fi{}{\stackrel{\ensuremath{\rightarrow}}{\mathrm{E}}}_{\ensuremath{\parallel}}$. where ${\stackrel{\ensuremath{\rightarrow}}{\mathrm{J}}}_{\ensuremath{\parallel}}$ and ${\stackrel{\ensuremath{\rightarrow}}{\mathrm{E}}}_{\ensuremath{\parallel}}$ are the components of the current density and the electric field parallel to the magnetic induction. The dynamical behavior of the magnetic structure at the flux-line-cutting threshold is shown to be governed by a special critical-state model similar to that proposed by previous authors. The resulting flux-line-cutting critical-state model, characterized in planar geometry by a parallel critical current density ${J}_{c\ensuremath{\parallel}}$ or a critical angle gradient ${k}_{c}$, is used to calculate predicted hysteretic ac flux-line-cutting losses in type-II superconductors in which the flux pinning is weak. The relation of the theory to previous experiments is discussed.
TL;DR: It seems possible that the beneficial effect of low dietary phosphorus, when dietary calcium is high, may be a result of a prepartal increase in efficiency of absorption of calcium and phosphorus from the gut caused by increased binding of 1,25-(OH)2D to intestinal receptors.
Abstract: Twenty Jersey cows were fed one of four prepartal diets: a)low calcium, low phosphorus (LCLP); b) low calcium, high phosphorus (LCLP); c) high calcium, low phosphorus (HCLP); or d)high calcium, high phosphorus (HCHP). Diets were fed for about 4 weeks prepartum. Blood samples were taken periodically, and the collected plasma analyzed for concentrations of calcium, phosphorus, hydroxyproline and 1,25 dihydroxyergocalciferol plus 1,25-dihydroxycholecalciferol (1,25-(OH)2D). Cows fed the LCLP and LCHP diets, when compared to cows fed the HCLP diet, had: a) greater concentrations of plasma 1,25-(OH)2D and hydroxyproline prepartum; b) greater plasma calcium concentrations at parturition; and c) less incidence (0 versus 4 cases) of parturient paresis. Thus, low calcium diets, regardless of dietary phosphorus intake, seemed to activate calcium homeostatic mechanisms before parturition by stimulating both bone and gut. Cows fed the HCLP diet had greater plasma calcium concentrations at parturition than did cows fed the HCHP, even though there was no measurable effect on plasma 1,25-(OH)2D and hydroxyproline concentrations during the prepartal period. It seems possible that the beneficial effect of low dietary phosphorus, when dietary calcium is high, may be a result of a prepartal increase in efficiency of absorption of calcium and phosphorus from the gut caused by increased binding of 1,25-(OH)2D to intestinal receptors.
Journal Article•
TL;DR: In this article, the crystal structure of a reverse pleochroic muscovite containing both Fe3+ and Mn3* has been determined by standard single-crystal X-ray methods.
Abstract: The crystal structure of a reverse pleochroic muscovite containing both Fe3+ and Mn3* has been determined by standard single-crystal X-ray methods. The mica has a 2Mr polytype, space grou-p C 2lc. Cellconstants are a :5.1988A esd 0.0021, b = 9.02664 esd 0.0019, c : 20.1058A esd 0.Cf.44, I = 95JE2' esd 0.039, V = 938.724 esd 0.48. Average bond lengths in tetrahedral sites are 1.6464 and 1.639A, comparable to bond lengths in SiAl tetrahedra of other analyzed muscovites, but also compatible with minor site occupancy by Fe3*. Mean bond strengths and electron densities for the sites are also compatible with but do not require minor amounts of tetrahedral Fe3*. A pleochroic mechanism related to tetrahedral Fe3*, therefore, cannot be ruled out. Thermal vibration ellipsoids of atoms in the octatedral layer, however, are oriented with long axes perpendicular to the layer, which suggests the possibility that reverse pleochroism is due instead to an unusual configuration of d-orbitals for octahedrally-coordinated Fe3* or Mn3*.
TL;DR: It is concluded that sensory factors cannot provide a viable account of letter end-effects and that letter and nonletter comparisons can improve the understanding of the sensory and cognitive factors involved in letter perception.
Abstract: Three experiments address the question of whether end-effects (the advantage for the first and last letters in multi-letter arrays) are due to sensory or cognitive factors. The basic strategy used was to compare letters with symbol stimuli that do not lend themselves to top-down processing. Serial position functions using central fixation were obtained in the first experiment for letters, digits, and symbols. End-effects were present with both letters and digits, indicating that processes limited to word recognition cannot be responsible for end-effects. Five-symbol arrays, however, yielded U-shaped reaction time functions, with poorest performance at the initial and terminal positions. The effects of array size and retinal placement were investigated with letters and symbols in a second experiment. Multi-letter and symbol arrays differed primarily in that letters showed end-effects that were independent of retinal placement, whereas symbols did not. The conclusion that multi-letter and symbol arrays are not processed in the same way was tested in a third experiment. Using a paradigm that eliminated processing order as a variable, the experiment obtained identical effects of ordinal position within an array for letters, digits, and symbols. It is concluded that sensory factors cannot provide a viable account of letter end-effects and that letter and nonletter comparisons can improve our understanding of the sensory and cognitive factors involved in letter perception.
TL;DR: The life cycle hypothesis has become the dominant mode used to analyze the effects of a social security system on private saving, the labor/leisure choice, and social welfare as mentioned in this paper.
Abstract: The life cycle hypothesis has become the dominant mode used to analyze the effects of a social security system on private saving, the labor/leisure choice, and social welfare. As both Barro and Samuelson indicate, a fully funded Social Security program (in a world of certainty) would drive out an equivalent amount of private saving. If the interest rate is r, the effects of a payment of a dollar into the social security pool while young would just offset* the effects of receiving (1+r) dollars as a transfer when retired. Papers by Diamond, Hi», and Samuelson, among others, have examined the effects of non-fully funded Social Security schemes in a growing economy. A non-fully funded program can be used to alter the private sector's saving rate and, hence, the capital/labor ratio. Social Security, then, can be used as a policy tool for achieving the (or some variant of the) golden rule growth path.
TL;DR: In this article, the authors present a method for a analyzing actoristic harmonic current propagation into an AC system, which is applied to two different systems and the responses of individual elements and the system as a whole were observed.
Abstract: This paper presents a method for a analyzing'charActeristic harmonic current propagation into an AC system. Frequency dependent models of AC network elements and loads have been developed for the appropriate range of frequencies. This methodology is applied to two different systems and the responsesof individual elements and the system as a whole were observed. The harmonic current flows in the systems appear to be related-to certain characteristics of the system and its elements. Input impedance at harmonic frequencies, the magnitude. of shunt capacitances on transmission lines, the size and location of the converters, and the representation of system loads are all found to be factors in cdetermining the magnitude of harmonic current flows in system elements.
TL;DR: The root growth is determined by differences between successive measurements on the same plants, the normal plant-to-plant variability does not introduce as much error as when plants from similar treatments are destroyed at each sampling period as discussed by the authors.
Abstract: Publisher Summary This chapter discusses some techniques for observing and recording root system parameters. Many techniques have been used to increase the accessibility of plant roots. The chapter concentrates on design features and operating characteristics of the Auburn, Alabama, and Ames, Iowa rhizotrons where the authors have conducted root research. Rhizotrons have several advantages over most other root study methods when extensive measurements are required. Successive measurements are made on the same plants each time and estimates of root growth at the root-soil interface are obtained quite rapidly. When root growth is determined by differences between successive measurements on the same plants, the normal plant–to-plant variability does not introduce as much error as when plants from similar treatments are destroyed at each sampling period. Instruments and sensors to measure soil or plant properties are easier to install and maintain in a rhizotron than in field plots. Sensors can be installed horizontally from the walkway through the viewing surface. This horizontal installation guards against water flow down the access hole, as often occurs with vertical installation of sensors. Rhizotrons are best suited to answer specific questions. Data needed to answer these questions must be accurate, timely, and reproducible. Rhizotrons can, for example, be very useful in root morphology or root physiology program when specific questions are formulated.