Showing papers by "University of Arizona published in 1981"
TL;DR: The dispersion equation of injected surface-plasma waves that propagate on thin metal films has been solved as a function of the film thickness, and splitting of the modes into two branches is observed.
Abstract: The dispersion equation of injected surface-plasma waves that propagate on thin metal films has been solved as a function of the film thickness, and splitting of the modes into two branches is observed. For one branch the imaginary part of the propagation constant goes to zero as the thickness of the metal decreases. Reflectivity calculations agree with this result, which predicts that one can obtain propagation distances that are more than 1 order of magnitude larger than observed before.
881 citations
TL;DR: As Voyager 1 flew through the Saturn system it returned photographs revealing many new and surprising characteristics of this complicated community of bodies, including small inner satellites that interact gravitationally with one another and with the ring particles in ways not observed elsewhere in the solar system.
Abstract: As Voyager 1 flew through the Saturn system it returned photographs revealing many new and surprising characteristics of this complicated community of bodies. Saturn's atmosphere has numerous, low-contrast, discrete cloud features and a pattern of circulation significantly different from that of Jupiter. Titan is shrouded in a haze layer that varies in thickness and appearance. Among the icy satellites there is considerable variety in density, albedo, and surface morphology and substantial evidence for endogenic surface modification. Trends in density and crater characteristics are quite unlike those of the Galilean satellites. Small inner satellites, three of which were discovered in Voyager images, interact gravitationally with one another and with the ring particles in ways not observed elsewhere in the solar system. Saturn's broad A, B, and C rings contain hundreds of "ringlets," and in the densest portion of the B ring there are numerous nonaxisymmetric features. The narrow F ring has three components which, in at least one instance, are kinked and crisscrossed. Two rings are observed beyond the F ring, and material is seen between the C ring and the planet.
781 citations
TL;DR: Saturation studies of [3H]5‐HT binding assayed in the absence or presence of 1 μM‐spiperone reveal a parallel shift in the Scatchard plot with no change in the dissociation constant of [2‐12 nM], but a significant decrease in the number of specific binding sites.
Abstract:
Certain neuroleptic drugs, such as spiperone and (+) butaclamol, can discriminate between two populations of [3H]5-hydroxytryptamine ([3H]5-HT) binding sites in rat brain. The butyrophenone neuroleptic spiperone shows the greatest selectivity for these two binding sites, having at least a 3000-fold difference between its dissociation constants (2-12 nM versus 35,000 nM) for the high- and low-affinity sites, respectively. Inhibition of [3H]5-HT binding by spiperone in rat frontal cortex and corpus striatum yields distinctly biphasic inhibition curves with Hill slopes significantly less than unity. Results from nonlinear regression analysis of these inhibition studies were consistent with a two-site model in each brain region. In the frontal cortex the high-affinity neuroleptic sites comprised about 60% of the total [3/H]5-HT binding sites whereas in the corpus striatum they accounted for only 20% of the sites. Furthermore, saturation studies of [3H]5-HT binding assayed in the absence or presence of 1 μM-spiperone (a concentration that completely blocks the high-affinity site while having minimal activity at the low-affinity site) reveal a parallel shift in the Scatchard plot with no change in the dissociation constant of [3H]5-HT, but a significant decrease (64% in frontal cortex or 28% in corpus striatum) in the number of specific binding sites. These observations are consistent with the existence of at least two populations of [3H]5-HT binding sites having a differential regional distribution in rat brain.
637 citations
TL;DR: This paper reviews the underlying theory of the customer contact approach to services and suggests specific ways in which this approach can be applied to a wide range of service systems.
Abstract: This paper reviews the underlying theory of the customer contact approach to services and suggests specific ways in which this approach can be applied to a wide range of service systems The approach holds that the potential efficiency of a service system is a function of the degree of customer contact entailed in the creation of the service product Based upon this conceptualization, a number of propositions about high contact systems are identified and some simple heuristics for service system design and operation are proposed Other approaches to operations management in services are reviewed and suggestions for further development of the contact approach are offered
618 citations
TL;DR: The development of theoretical community ecology over the last two decades is examined in an attempt to determine why some avenues of investigation have proven disappointing, whereas others, such as the theory of island biogeography, have enjoyed at least modest success.
Abstract: In 1959, in his seminal paper “Homage to Santa Rosalia,” G. E. Hutchinson asked, Why are there so many kinds of organisms? This paper focused attention on problems of species diversity and community organization that have occupied many theoretical and empirical ecologists for the last two decades. In the present paper I evaluate the attempt to answer Hutchinson's question by considering three topics. First, I reexamine the main themes which Hutchinson developed in “The Homage” and call attention to the central importance of energetic relationships in his view of ecological communities. Second, I examine the development of theoretical community ecology over the last two decades in an attempt to determine why some avenues of investigation, such as competition theory, have proven disappointing, whereas others, such as the theory of island biogeography, have enjoyed at least modest success. Finally, I suggest that future attempts to understand patterns of species diversity might focus on developing two kinds of theoretical constructs: capacity rules, which describe how characteristics of the physical environment determine its capacity to support life, and allocation rules, which describe how limited energetic resources are subdivided among species.
475 citations
TL;DR: In this paper, the effect of a wavy interplanetary current sheet on the solar modulation of galactic cosmic rays is studied, and it is concluded that changes in the waviness of the current sheet can have an important, and perhaps dominant, effect in producing solar modulation.
Abstract: The effect of a wavy interplanetary current sheet on the solar modulation of galactic cosmic rays is studied. A simple model of the heliospheric magnetic field is employed in which there is an Archimedean spiral magnetic field directed in one direction above the current sheet and another direction below. The current sheet itself is taken to be the extension by the solar wind of a surface that, at the sun, is a plane inclined at an angle alpha to the solar equator. Two magnetic sectors will therefore be seen by an observer within an angle alpha of the heliographic equator. A simple approximate model is used to investigate modulation. As the tilt angle alpha is increased from zero, it is found that the cosmic-ray intensity decreases. For reasonable variation of alpha from approximately 10 deg to approximately 30 deg, the change in intensity can be compared to that observed as one goes from solar minimum to solar maximum. It is concluded that changes in the waviness of the interplanetary current sheet can have an important, and perhaps dominant, effect in producing solar modulation of galactic cosmic rays.
399 citations
TL;DR: The Ancestral Rocky Mountains as mentioned in this paper were intracratonic block uplifts that formed in Colorado and the surrounding region during Pennsylvanian time, and their development related to the collision of North America with South America-Africa, which produced the Ouachita-Marathon orogeny.
Abstract: The Ancestral Rocky Mountains were intracratonic block uplifts that formed in Colorado and the surrounding region during Pennsylvanian time. Their development related to the collision of North America with South America–Africa, which produced the Ouachita-Marathon orogeny. In Early Pennsylvanian time, suturing was taking place only in the Ouachita region, and foreland deformation took place only in the mid-continent. By Middle Pennsylvanian time, the length of the suture zone had increased, and it was active from the Ouachita to the Marathon region. The extent of cratonic deformation also increased in intensity and in areal extent, culminating in the Ancestral Rocky Mountains. In Late Pennsylvanian time, suturing was taking place only in the Marathon region, and cratonic deformation decreased in extent and spread southward into New Mexico and West Texas. We suggest that the Ancestral Rocky Mountains, and related features over a broad area of the western United States, were formed while an irregularly bounded peninsula of the craton (including the transcontinental arch) was pushed northwestward by the progressive collision-suturing of North America and South America–Africa. This intraplate deformation is, in some respects, like the deformation of Asia in response to the Cenozoic collision with India.
391 citations
TL;DR: It is proposed that SPM will prove valuable in the regional localization of normal and abnormal functions in other clinical situations in patients with brain tumors, boys with dyslexia, and control subjects.
368 citations
TL;DR: In this article, the meta-analytic technique was used to synthesize experimental research findings on the relationship between level of teacher questioning and student achievement, and the results showed that gains in achievement can be expected when higher cognitive questions assume a predominant role during classroom instruction.
Abstract: The meta-analytic technique was used to synthesize experimental research findings on the relationship between level of teacher questioning and student achievement. Twenty studies on teachers’ use of “higher” and “lower” cognitive questions were reviewed. Higher cognitive questions require pupils to manipulate information to create and support a response; lower cognitive questions call for verbatim recall or recognition of factual information. Effect sizes were computed to investigate the impact of program monitoring, experimental validity, and level of teacher questioning. Results show that gains in achievement can be expected when higher cognitive questions assume a predominant role during classroom instruction.
357 citations
01 Aug 1981
TL;DR: In this paper, a review of the first edition of the Russian edit ion published by "Nauka", Moscow, 1973 can be found, along with a discussion of the use of surface waveguides and whispering ga l l l e ry modes.
Abstract: This is an Engl ish t ranslat ion of t he Russian edit ion published by "Nauka", Moscow, 1973. The book closely resembles the w e l l received 1st Ed i t ion tha t was a lso publ ished i n t r a n s l a t i o n by Academic Press i n 1960. The new problems t rea ted in th i s ed i t ion inc lude the case of a waveguide or duct where the proper t ies vary both i n t h e v e r t i c a l and t h e ho r i zon ta l d i r ec t ion . The treatment, however, is rather cursory and mode conversion i s not rea l ly cons idered beyond t h a t found i n t h e ea r ly ( c i r ca 1965) adiabatic approaches. The theory of surface waveguides and whispering ga l l e ry modes have also been added. But again the coverage of t h i s new ma te r i a l i s spot ty . Unfor tuna te ly the exce l len t refe rence mater ia l on the underwater sound channel has been abbreviated in this new ed i t ion . In this review we should cal l a t t e n t i o n t o a number of o the r un fo r tuna te i f no t undes i r ab le f ea tu re s . Gauss i an un i t s fo r t he electromagnet ic port ions are used so t h a t comparisons with contemporary wave theory s t u d i e s are hampered. The ma te r i a l is over 10 yea r s o ld in sp i t e o f t he e f fo r t s by Brekhovskikh t o i n c l u d e t h e latest papers when he submit ted the manuscript to the publ isher in 1971. The attempt by the t r ans l a to r t o upda te t h e book cons i s t s of a lengthy appendage of non-cited t i t les of papers mostly published in the Journal of the Acoust ical Society of America. This ra ther biased perspect ive added by t h e t r a n s l a t o r is i n c o n t r a s t t o t h e heal thy balance of acoust ic , e las t ic and electromagnet ic subjects t reated by Academician Brekhovskikh. As i n t h e 1960 ed i t i on , t he der iva t ions a re se l f -conta ined wi th a minimum of mathematical formalism. In s p i t e of t h e above comments, wave t h e o r i s t s will f i n d t h i s a use fu l add i t ion to the i r l ib rary , p rovided they a l ready do not own t h e 1960 ed i t i on . But i t i s a p i t y tha t pub l i she r s would not merely issue a supplement with addenda and corrigenda along with a modes t ly p r i ced r ep r in t ing o f t he i r f i r s t ed i t i on .
TL;DR: Both age and sex, in addition to atopic status, relate to IgE level, and males have higher levels than females at any given age, and women over age 75 yr have the lowest levels.
Abstract: The distribution of total serum IgE determined by the paper radioimmunosorbent test (PRIST) is examined in a large random stratified community population. Prior to logarithmic conversion the distribution of this immunoglobulin is not normal, with almost 40% of values below 20 IU/ml. A normal distribution occurs following such conversion, with a geometric mean value of 32.1 IU/ml. Both age and sex, in addition to atopic status, relate to IgE level. In both sexes highest levels occur among 6- to 14-year-olds, and males have higher levels than females at any given age. Women over age 75 yr have the lowest levels (geometric mean 9.2 IU/ml). Subjects with positive skin test results have several times the concentration of IgE as their nonatopic counterparts.
TL;DR: In this article, a model of the anomalous component of the quiet-time cosmic ray flux is presented in which ex-interstellar neutral particles are accelerated continuously in the polar regions of the solar-wind termination shock, and then drift into the equatorial region of the inner heliosphere.
Abstract: A model of the anomalous component of the quiet-time cosmic ray flux is presented in which ex-interstellar neutral particles are accelerated continuously in the polar regions of the solar-wind termination shock, and then drift into the equatorial regions of the inner heliosphere. The observed solar-cycle variations, radial gradient, and apparent latitude gradient of the anomalous component are a natural consequence of this model.
TL;DR: In this paper, the behavior of optical turbulence and periodic oscillations with a hybrid optically bistable device with a delay in the feedback was predicted. But the authors did not consider the effect of the delay on the delay of the feedback.
Abstract: Optical turbulence and periodic oscillations are easily seen with a hybrid optically bistable device with a delay in the feedback. The behavior of these instabilities is in good agreement with the recent work of Ikeda, Daido, and Akimoto, who predicted them for both ring-cavity and delay-line hybrid devices.
TL;DR: The isotopic method of dietary analysis is extended by using both the organic and inorganic phases of bone with equally good results and allows dietary analysis of bone over 10,000 years old by using the inorganic phase, which is more stable in fossil material.
Abstract: Studies evaluating the distribution of stable carbon isotopes in bone and other tissues of both human and non-human animals have recently been reported1–6. Those investigations which examined the isotopic composition of bone have concentrated on the analysis of bone collagen and demonstrated that the 13C/12C ratios in bone collagen are directly related to the 13C/12C ratios of primary photosynthesizing plants in the diets of the animals concerned6–8. With regard to archaeological applications, such analyses have been limited to relatively young samples because of the instability of collagen in bone. We have extended the isotopic method of dietary analysis by using both the organic and inorganic phases of bone with equally good results. In the case of material over a few thousand years old, unless special conditions have preserved collagen, analysis of the organic phase of bone is no longer practical due to its deterioration9. The technique reported here allows dietary analysis of bone over 10,000 years old by using the inorganic phase, which is more stable in fossil material.
TL;DR: XMP is a hierarchically structured library of FORTRAN subroutines for linear programming that helps facilitate algorithmic research and model development in operations research and related disciplines.
Abstract: XMP is a hierarchically structured library of FORTRAN subroutines for linear programming. Its purpose is to facilitate algorithmic research and model development in operations research and related disciplines. The intended audience for XMP, the design goals that were identified as essential for serving that audience, and the way in which those goals were embodied in a working system, are described. Experience with XMP shows that an LP system can be designed primarily for flexibility and ease of modification without too great a sacrifice in computational efficiency.
TL;DR: In this article, it was shown that the associated random variables of a strictly stationary second order sequence can be associated, such that any two coordinatewise nondecreasing functions of the $X_i$'s are nonnegatively correlated.
Abstract: Let $X_1, X_2, \cdots$ be a strictly stationary second order sequence which is "associated"; i.e., is such that any two coordinatewise nondecreasing functions of the $X_i$'s (of finite variance) are nonnegatively correlated. If $\sum_j \operatorname{Cov}(X_1, X_j) < \infty$, then the partial sum processes, $W_n(t)$, defined in the usual way so that $W_n(m/n) = (X_1 + \cdots + X_m - mE(X_1))/\sqrt n$ for $m = 1, 2, \cdots$, converge in distribution on $C\lbrack 0, T\rbrack$ to a Wiener process. This result is based on two general theorems concerning associated random variables which are of independent interest.
TL;DR: Comparison of CO(2) exchange rate, RuP(1,5-bisphosphate) level, and activation of the carboxylase indicates that light limitation of photosynthesis can be due to two factors: the availability of RuP (2) in dark to dim light andactivation of the RuP.(2) carboxylyase inDim light and higher irradiances.
Abstract: In limiting light the activation of ribulose-1,5-bisphosphate (RuP2) carboxylase [3-phospho-D-glycerate carboxylyase (dimerizing), EC 4.1.1.39] in leaf extracts of 7- to 8-day-old wheat seedlings changed proportionally with the photosynthetic rate of the intact plants. Higher rates of photosynthesis, induced by increasing irradiances, were accompanied by an increase in activation of the leaf RuP2 carboxylase, while RuP2 levels remained unchanged. The degree of activation varied from 20% to 60% of full activation at irradiances of 225-1650 μE/m2·s (photosynthetically active radiation; E = einstein, 1 mol of photons). Between 225 μE/m2·s and darkness, activation approached 50% while RuP2 levels dropped more than 90%. During steady-state photosynthesis, levels of the substrate RuP2 were 250-300 nmol/mg of chlorophyll in the leaves and were similar at all irradiances above 225 μE/m2·s (25% of light saturation). When velocities of the carboxylase in leaf extracts were corrected for CO2 levels estimated to exist within the leaf, they compared favorably with the photosynthetic rates of the intact seedlings. Comparison of CO2 exchange rate, RuP2 level, and activation of the carboxylase indicates that light limitation of photosynthesis can be due to two factors: the availability of RuP2 in dark to dim light and activation of the RuP2 carboxylase in dim light and higher irradiances.
Book•
01 Jan 1981TL;DR: Cosmology: The Science of the Universe as discussed by the authors is an introduction to past and present cosmological theory and provides a comprehensive survey of man's current understanding of the universe and its history.
Abstract: Cosmology: The Science of the Universe is an introduction to past and present cosmological theory. For much of the world's history, cosmological thought was formulated in religious or philosophical language and was thus theological or metaphysical in nature. However, cosmological speculation and theory has now become a science in which the empirical discoveries of the astronomer, theoretical physicist, and biologist are woven into intricate models that attempt to account for the universe as a whole. Professor Harrison draws on the discoveries and speculations of these scientists to provide a comprehensive survey of man's current understanding of the universe and its history. Tracing the rise of the scientific method, the major aim of this book is to provide an elementary understanding of the physical universe of modern times. Thoroughly revised and updated, this second edition extends the much acclaimed first edition taking into account the many developments that have occurred.
TL;DR: In this paper, a highly excited (Rydberg) atom bathed in blackbody radiation is perturbed in two ways: a dynamic Stark shift is induced by the off-resonant components of the black body radiation.
Abstract: A highly excited (Rydberg) atom bathed in blackbody radiation is perturbed in two ways. A dynamic Stark shift is induced by the off-resonant components of the blackbody radiation. Additionally, electric-dipole transitions to other atomic energy levels are induced by the resonant components of the blackbody radiation. This depopulation effect shortens the Rydberg-state lifetime, thereby broadening the energy level. Calculations of these two effects in many states of hydrogen, helium, and the alkali-metal atoms Li, Na, K, Rb, and Cs are presented for $T=300$ K. Contributions from the entire blackbody spectrum and from both discrete and continuous perturbing states are included. The accuracy is considerably greater than that of previous estimates.
TL;DR: A number of other potentially useful methods of protein removal are described using the much moresensitive Lowry method of protein determination to evaluate their efficiency.
TL;DR: In this paper, the authors report on two studies which compared scenic landscape perceptions of Yugoslavians, West Indians and Americans of several ethnic backgrounds and identify important differences among groups in the perception of landscapes with and without man-made structures.
TL;DR: In this article, the evolution and current state of fashion theory focusing on fashion life cycles are reviewed and analyzed in two time frames, long run secular trends spanning decades and fashion life cycle.
Abstract: This paper reviews the evolution and current state of fashion theory focusing on fashion life cycles. Fashion cycles are analyzed in two time frames, long run secular trends spanning decades and ce...
TL;DR: A model for calculating the energy cost of burrowing by fossorial rodents is presented and used to examine the energetics of foraging by burrows and finds that minimizing energy expended per meter of tunnel constructed maximizes efficiency of foraged by burrowing in the desert scrub.
Abstract: A model for calculating the energy cost of burrowing by fossorial rodents is presented and used to examine the energetics of foraging by burrowing. The pocket gopher Thomomys bottae (Rodentia: Geomyidae) digs burrows for access to food. Feeding tunnels of Thomomys are broken into segments by laterals to the surface that are used to dispose of excavated soil. Energy cost of burrowing depends on both soil type and on burrow structure, defined by the length of burrow segments, angle of ascent of laterals, depth of feeding tunnels, and burrow diameter. In a desert scrub habitat, Thomomys adjust burrow segment length to minimize cost of burrowing. Observed segment lengths (mean=1.33 m) closely approximate the minimum-cost segment length of 1.22 m. Minimizing energy expended per meter of tunnel constructed maximizes efficiency of foraging by burrowing in the desert scrub. Burrow diameter and cost of burrowing increase with body size, while benefits do not, so foraging by burrowing becomes less enconomical as body size increases. Maximum possible body size of fossorial mammals depends on habitat productivity and energy cost of burrowing in local soils.
TL;DR: In this paper, the qualitative nature of infinite clusters in percolation models is investigated and the results apply to both independent and correlated percolations in any dimension, concern the number and density of infinite cluster, the size of their external surface, the value of their (total) surface-to-volume ratio, and the fluctuations in their density.
Abstract: The qualitative nature of infinite clusters in percolation models is investigated. The results, which apply to both independent and correlated percolation in any dimension, concern the number and density of infinite clusters, the size of their external surface, the value of their (total) surface-to-volume ratio, and the fluctuations in their density. In particular it is shown thatN0, the number of distinct infinite clusters, is either 0, 1, or ∞ and the caseN0=∞ (which might occur in sufficiently high dimension) is analyzed.
TL;DR: In this paper, a new numerical scheme is proposed for the dispersion-convection equation which combines the utility of a fixed grid in Eulerian coordinates with the computational power of the Lagrangian method.