Showing papers by "University of Illinois at Urbana–Champaign published in 1970"
TL;DR: Today, as a step towards the control of complex dynamic systems, models are being used ubiquitously, being modelled, for instance, are the air traffic flows around New York, the endocrine balances of the pregnant sheep, and the flows of money among the banking centres.
Abstract: Today, as a step towards the control of complex dynamic systems, models are being used ubiquitously. Being modelled, for instance, are the air traffic flows around New York, the endocrine balances of the pregnant sheep, and the flows of money among the banking centres.
1,017 citations
TL;DR: In this paper, it was shown that by using alternate layers of materials with high and low elastic constants resolved shearing stresses of the order of ε( √ n ϵ(n 2 ) −1 −1/n −1 )$ will be required in order to drive dislocations through the combination.
Abstract: It is shown that by using alternate layers of materials with high and low elastic constants resolved shearing stresses of the order of $\frac{{\ensuremath{\mu}}_{\mathrm{low}}}{100}$ will be required in order to drive dislocations through the combination. The layers should be so thin that a Frank Read source cannot operate inside one layer. The low-elastic-constant material should be such that perfect dislocations rather than partials occur in bulk specimens of the material. Several possible combinations are suggested.
945 citations
TL;DR: In this paper, Fishbein's extension of Dulany's (1967) theory of propositional control was tested in the context of the Prisoner's Dilemma (PD) game.
794 citations
TL;DR: The work described here was intended to add to present theoretical knowledge of stability in large systems, for instability usually appears as a self-generating catastrophe.
Abstract: MANY systems being studied today are dynamic, large and complex: traffic at an airport with 100 planes, slum areas with 104 persons or the human brain with 1010 neurones. In such systems, stability is of central importance, for instability usually appears as a self-generating catastrophe. Unfortunately, present theoretical knowledge of stability in large systems is meagre: the work described here was intended to add to it.
711 citations
TL;DR: In this paper, the Boltzmann equation of dilute gases was derived with the aid of a generalized Langevin equation due to Mori, which was then used to obtain selfconsistent closed equations to determine time correlation functions of critical fluctuations.
699 citations
TL;DR: Although leaf enlargement did not occur initially, enlargement resumed toward the end of the desiccation period, however, the rate of enlargement was not as rapid as in the well watered control, nor did it return to the control rate when the plant was rewatered.
Abstract: Rates of photosynthesis, dark respiration, and leaf enlargement were studied in soil-grown corn (Zea mays), soybean (Glycine max), and sunflower (Helianthus annuus) plants at various leaf water potentials. As leaf water potentials decreased, leaf enlargement was inhibited earlier and more severely than photosynthesis or respiration. Except for low rates of enlargement, inhibition of leaf enlargement was similar in all three species, and was large when leaf water potentials dropped to about -4 bars.Intact sunflower leaves were held for 4 days at leaf water potentials which permitted maximal photosynthesis and respiration, but which inhibited leaf enlargement. Although leaf enlargement did not occur initially, enlargement resumed toward the end of the desiccation period. However, the rate of enlargement was not as rapid as in the well watered control, nor did it return to the control rate when the plant was rewatered.
557 citations
TL;DR: In this paper, photo and dark current and capacitance transient experiments are described which can provide highly accurate and unique data of the electronic properties of impurity centers in semiconductors such as energy level, multiplicity of charge state, thermal and optical emission rates, thermal capture rates and the dependences of the rates and cross sections on sample temperature, static electric field and photon energy.
Abstract: Photo and dark current and capacitance transient experiments are described which can provide highly accurate and unique data of the electronic properties of impurity centers in semiconductors such as energy level, multiplicity of charge state, thermal and optical emission rates, thermal capture rates, thermal and optical cross sections and the dependences of the rates and cross sections on sample temperature, static electric field and photon energy. These experiments are grouped into four categories in the discussion according to the temperature (below and above freeze-out or negligible and finite thermal rates) and presence or absence of optical excitation at the impurity center. Each category is subdivided into a number of cases according to the method used to set the initial charge state of the impurity center prior to the measurements. Methods of setting the initial state include electrical switching of the bias voltage and optical excitation using either interband or band to impurity monochromatic light. Experimental examples are given for many of the experiment methods discussed.
422 citations
TL;DR: This paper is an attempt to reconcile the old archeological, historical, agricultural and botanical literature with the more recent data and to establish a working hypothesis on the domestication of the soybean.
Abstract: Soybeans, together with bananas, barley, common beans, cassavas, coconuts, maize, peanuts, potatoes, rice, sorghum, sugar beets, sugarcane, sweet potatoes and wheat, are man's principal food plants (12). Today, the soybean, like so many other food plants, is taken for granted, that is, without appreciable forethought as to when and where it was adapted to the needs of man, how, when and by whom it was disseminated, and whether or not the distribution of soybeans took place in prehistoric or within the modern era (73). In addition to the general lack of urgency in studying the origin of the soybean, it is unfortunate that the literature concerned with the antiquity and historical development of the soybean and its agricultural consequences is fraught with errors and misconceptions. This is mainly due to two reasons: (a) the soybean is autochthonous to the Orient, where western scientists are at a linguistic disadvantage with respect to historical records; (b) it is only in recent times that attention has been focused on studying in depth, using a team approach, the interrelationships between the domestication of plants and animals and development and needs of human society (10, 32, 67, 115). During the past 30 years, many Chinese historical books, commentaries and material media have been translated into western languages and a large amount of archeological material has been uncovered, both on mainland China and in Taiwan. This paper is an attempt to reconcile the old archeological, historical, agricultural and botanical literature with the more recent data and to establish a working hypothesis on the domestication of the soybean.
386 citations
TL;DR: In this paper, the authors present a set of apps that can be used to find the most relevant information about a person walking in a certain environment, such as a city, a walk, a drive, or a walk.
Abstract: 5. T h e ope ra to r s S a n d s . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275 Some app l i c a t i ons of S a n d s . . . . . . . . . . . . . . . . . . . . . . . . 281 R a n d o m walk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281 H a a r a n d W a l s h ser ies . . . . . . . . . . . . . . . . . . . . . . . . . . 284 Loca l conve rgence of m a r t i n g a l e t r a n s f o r m s . . . . . . . . . . . . . . . . . 285
364 citations
TL;DR: Seven mutants of E. coli with temperature-sensitive synthesis of DNA have been isolated and it has not yet proved possible to map accurately the mutants showing substantial residual synthesis, and the possibility that these mutations are in a different gene has not been excluded.
Abstract: Seven mutants of E. coli with temperature-sensitive synthesis of DNA have been isolated. Synthesis of RNA, protein and DNA precursors does not appear to be directly affected. The mutants can be divided into at least two groups on the basis of their pattern of DNA synthesis, their ability to support phage growth at 41° and their genetic mapping. Mutants of the first group are heterogeneous in their pattern of DNA synthesis at 40°. Some mutants cease DNA synthesis abruptly upon transfer to 40° and any residual DNA synthesis is barely detectable. In others there is substantial residual synthesis at 40°. All these Group 1 mutants are alike, however, in that they support the growth of phage T4 but not Lambda at 41°. Two mutants with barely detectable residual DNA synthesis carry DNA mutations which have been mapped by P1 transduction and show about 72% linkage to the malB locus. It has not yet proved possible to map accurately the mutants showing substantial residual synthesis, and the possibility that these mutations are in a different gene(s) has not been excluded. A single mutant has been placed in a second group. Like some Group 1 mutants it synthesizes substantial amounts of DNA at 40° before synthesis stops. However, unlike them it supports the growth of T4 and Lambda at 41°. The DNA mutation maps near the leu locus. Certain properties of this mutant are consistent with the idea that initiation of DNA synthesis is temperature-sensitive in this strain.
303 citations
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01 Jan 1970TL;DR: The probability calculus is interpreted as a semantics for truth functional logic and conditional propositions are introduced as propositions whose absolute probability is equal to the conditional probability of the consequent on the antecedent.
Abstract: The aim of the paper is to draw a connection between a semantical theory of conditional statements and the theory of conditional probability. First, the probability calculus is interpreted as a semantics for truth functional logic. Absolute probabilities are treated as degrees of rational belief. Conditional probabilities are explicitly defined in terms of absolute probabilities in the familiar way. Second the probability calculus is extended in order to provide an interpretation for counterfactual probabilities — conditional probabilities where the condition has zero probability. Third, conditional propositions are introduced as propositions whose absolute probability is equal to the conditional probability of the consequent on the antecedent. An axiom system for this conditional connective is recovered from the probabilistic definition. Finally, the primary semantics for this axiom system, presented elsewhere, is related to the probabilistic interpretation.
TL;DR: Existence energy requirements in cages, measured for 18 species weighing from 9 to 4300 g and belonging to three different orders, provide sufficient data to test variation with the size of the bird and to correlate existence metabolism with standard metabolism.
Abstract: Standard metabolism is the energy requirement, usually measured over short periods, of an individual at complete rest and in a postabsorptive state and is of considerable importance to physiologists. Of greater ecological interest, however, is the energy requirement of normal activities under free-living conditions. This may be approximated (within about 13 per cent in the Blue-winged Teal, Anas discors; Owen 1968) by measuring the rate of food utilization over long periods of time of individuals confined in cages. With caged birds, the caloric value of the excreta (excretory energy, including the wastes from both the alimentary tract and kidneys) subtracted from the gross energy (intake over a period of days) gives the metabolized energy. When the bird maintains a constant weight, the energy metabolized is sufficient just for existence. This existence energy, or existence metabolism, progressively increases with decrease in ambient temperature to a maximum at the lowest ambient temperature tolerated (Kendeigh 1949; 1969). Existence metabolism includes the energy expended in standard metabolism, specific dynamic action, and locomotor activity within the cage. Cages vary in size, dependent on the species, to permit approximately the same amount of free movement, e.g., hopping but not flight (Martin 1967). The energy cost of free existence is greater than that of cage existence in proportion to the amount of locomotor activity involved. Existence energy requirements in cages, measured for 18 species weighing from 9 to 4300 g and belonging to three different orders, provide sufficient data to test variation with the size of the bird and to correlate existence metabolism with standard metabolism.
TL;DR: It was concluded that the C(4) pathway confers no particular ability to withstand low leaf water potentials and corn was less able to withstand severe desiccation without tissue death.
Abstract: Rates of net photosynthesis were studied in soil-grown corn (Zea mays) and soybean (Glycine max) plants having various leaf water potentials. Soybean was unaffected by desiccation until leaf water potentials were below -11 bars. Rates of photosynthesis in corn were inhibited whenever leaf water potentials dropped below -3.5 bars.The differences in photosynthetic behavior could be attributed solely to differences in stomatal behavior down to leaf water potentials of -16 bars in soybean and -10 bars in corn. Below these potentials, other factors in addition to stomatal closure caused inhibition, although their effect was relatively small.Corn, which has the C(4)-dicarboxylic acid pathway for carbon fixation, generally had a higher rate of photosynthesis than soybean during desiccation. Nevertheless, since inhibition of photosynthesis began at higher potentials than in soybean, and since corn was less able to withstand severe desiccation without tissue death, it was concluded that the C(4) pathway confers no particular ability to withstand low leaf water potentials.
01 Oct 1970
TL;DR: In this paper, the electrophoresis of an arbitrary shape in an unbounded fluid is treated analytically, subject to the restrictions that the local Debye length is much smaller than the local radii of curvature and surface conductivity is negligible.
Abstract: The electrophoresis of an insulating body of arbitrary shape in an unbounded fluid is treated analytically, subject to the restrictions that the local Debye length is much smaller than the local radii of curvature and surface conductivity is negligible. The flow is shown to be irrotational. The Smoluchowski equation is shown to be valid for a particle of any shape, as is frequently assumed.
TL;DR: In this paper, a comprehensive study of electric field effects on optical absorption by Wannier excitons is presented, showing that the electron-hole interaction enhances these oscillations near an ${M}_{0}$-type edge (positive effective masses) and quenches them near an${M}{3}$)-type edge(negative effective masses).
Abstract: A comprehensive study of electric field effects on optical absorption by Wannier excitons is presented, showing field effects on both bound and continuum states. The calculations and results have been simplified by defining appropriate dimensionless parameters such that the eigenvalues are independent of field when expressed in terms of these parameters. A general normalization procedure for wave functions with continuous eigenvalues is outlined. The effect of the electron-hole interaction on the electric-field-induced oscillations is demonstrated, with the result that the electron-hole interaction enhances these oscillations near an ${M}_{0}$-type edge (positive effective masses) and quenches these oscillations near an ${M}_{3}$-type edge (negative effective masses). This effect would inhibit the observation of ${M}_{3}$-type edges in electroreflectance.
TL;DR: In this article, the onset of axisymmetric convection in cylindrical layers of fluid heated from beneath is investigated for various radius-to-height ratios and upper and lower bounds on the critical Rayleigh number for such flows are computed, and the structure of the convective flow is investigated.
TL;DR: Results indicate that Compound I of chloroperoxidase may contain a reactive oxygen atom, and by analogy with organic mechanisms for the decomposition of peracids, these results indicate that the enzyme also oxidizes ethanol to form acetaldehyde.
TL;DR: The 5S RNA genes are placed within the region 56E-F of the right arm of chromosome 2 of Drosophila melanogaster, and their localization was determined from autoradiographs, where the radioactivity from hybrids of [3H]RNA and DNA was confined to the 56E -F segment.
Abstract: [ 3H ] RNA with a high specific activity was prepared from larvae of Drosophila melanogaster grown 4 days in contact with [ 3H ] uridine. Purified tritiated 5 S RNA was annealed to the DNA of polytene chromosomes, which had been denatured in formamide. The 5 S RNA genes are placed within the region 56E-F of the right arm of chromosome 2. This localization was determined from autoradiographs, where the radioactivity from hybrids of [ 3H ] RNA and DNA was confined to the 56E-F segment.
TL;DR: A model is suggested for protein synthesis which depends upon conformational changes in tRNA and allosteric transitions in place of translocation.
Abstract: A model is suggested for protein synthesis which depends upon conformational changes in tRNA and allosteric transitions in place of translocation.
TL;DR: 2 UV absorbent compounds, presumably steroids, were present in all ovarian venous plasma extracts of rabbits with ovectomized follicles and absent in all other extracts studied and the identification of these 2 compounds is in progress.
Abstract: To study the effect of the oocyte on the functional activity of granulosa cells, clear mature follicles of estrous rabbits were either punctured or ovectomized. Three days after treatment, granulosa cells of punctured follicles failed to show histological signs of luteinization. Six days after puncturing both oocytes and granulosa cells were degenerate histologically. Three days after ovectomy, granulosa cells showed histological characteristics of lutein cells. These lutein-like cells had disintegrated 8 days after ovectomy. The concentration of progesterone in the ovarian venous plasma 3 days after ovectomy was significantly higher than that present in the effluent plasma from ovaries with punctured follicles. The reverse was true for 20αhydroxy- 4-pregnen-3-one. Furthermore, 2 UV absorbent compounds, presumably steroids, were present in all ovarian venous plasma extracts of rabbits with ovectomized follicles and absent in all other extractsstudied. The identification of these 2 compounds is in progress...
TL;DR: In the many aromatic fluorophores examined, unlike a few nonaromatic ones, transfer is much decreased or altogether undetectable on excitation at the red edge of the absorption spectrum.
Abstract: Electronic energy transfer among identical molecules has been followed by the depolarization of the fluorescence in concentrated solutions as well as in dimers, polymers, and micelle systems. In the many aromatic fluorophores examined, unlike a few nonaromatic ones, transfer is much decreased or altogether undetectable on excitation at the red edge of the absorption spectrum. The phenomenon is not due to the transfer taking place during a small fraction of the total fluorescence lifetime, nor is it explainable by a decrease in overlap of absorption and emission upon edge excitation.
TL;DR: It was demonstrated that glucose was incorporated into fatty acids to a much greater extent by mammary tissue slices of the rat than by cow tissue slices, and a lack of ATP-citrate lyase and NADP-malate dehydrogenase in cow mammary cytosol suggested that the tissue of the cow has alternate sources of NADPH.
TL;DR: In this paper, Flynn and Stoneham used the potential associated with the pth interstice (the division of K into terms associated with different interstices) for light interstitials in metals.
Abstract: Quantum Theory of Diffusion with Application to Light Interstitials in Metals, C. P. Flynn and A. M. Stoneham [Phys. Rev. B 1, 3966 (19'70)]. A notational error might cause confusion. In Eq. (3.6), X„, should read R„„the potential associated with the pth interstice (the division of K„, into terms associated with different interstices is to some extent arbitrary but does not affect subsequent steps). Equations after (3.6) should all contain &&+X„,rather than X„,alone. The proper terms were used throughout the actual calculations, so the conclusions are not affected. A final point is that the integrand in Eq. (A6) should contain x rather than xa as printed. The related formulas are correct.
TL;DR: The consolidation characteristics of clays are controlled by mechanical and physico-chemical effects as discussed by the authors, and one-dimensional consolidation tests indicate that one or the other usually dominates in clays.
Abstract: The consolidation characteristics of clays are controlled by mechanical and physico-chemical effects. Although these effects operate simultaneously one-dimensional consolidation tests indicate that one or the other usually dominates. The consolidation characteristics of sands, mica, and kaolinite are mechanically controlled whereas those of smectite are physico-chemically controlled. Illite occupies an intermediate position in that the virgin compression curve seems to be controlled by mechanical variables, whereas the swelling curve is influenced by both effects; the physico-chemical effect is more important when the adsorbed cations are monovalent and the pore water electrolyte concentration is low.
11 May 1970
TL;DR: In this article, the authors used the well-known singular integral equation approach for deriving an alternate form of eigenvalue equation with superior convergence properties using only a 2x2 matrix equation.
Abstract: Dispersion characteristics of shielded microstrip lines are investigated using a new technique. The method utilizes the well-known singular integral equation approach for deriving an alternate form of eigenvalue equation with superior convergence properties. It is shown that accurate numerical results may be obtained from this eigenvalue equation using only a 2x2 matrix equation. In comparison, the conventional formulation of the problem requires the use of matrices that are much larger in size. Aside from the numerical efficiency, the simplicity of the method makes it possible to conveniently extract higher order modal solutions for the propagation constants that affect the high-frequency application of microstrip lines. Even though the derivation of the determinantal equation requires some intricate mathematical manipulations, the user may bypass these completely and use the final eigenvalue equation which is programmable on the computer.
TL;DR: The number of estrogen binding sites in uterine cytoplasm on a per cell basis reaches a maximum by day 10 of life in both intact and castrate female rats, and is probably an autonomous property of uterine cells.
Abstract: The number of estrogen binding sites in uterine cytoplasm on a per cell basis reaches a maximum by day 10 of life in both intact and castrate female rats. After this peak is reached, the number of binding sites per cell decreases, and the ratio remains constant until days 22 to 23 of life. Thus, the ontogeny of the estrogen binding protein is not dependent upon estrogen from the ovary and is probably an autonomous property of uterine cells. Sedimentation values and dissociation constants of the protein when the animals are 5 to 10 days of age are similar to those of the 22-day-old animal, indicating that the same protein is present throughout postnatal development.
TL;DR: In this article, the hydrides and deuterides of thorium with H-or D-to-metal atom ratios of 3.6 to 3.65 were found to be type-II superconductors with 25-30 kG at 1.1 K.
Abstract: Superconductivity has been observed in the hydrides and deuterides of thorium with H-or D-to-metal atom ratios of 3.6 to 3.65. Transition temperatures fall in the range from 8.05 to 8.35 K. These materials are apparently type-II superconductors with ${H}_{c2}$ of the order of 25-30 kG at 1.1 K. There is no evidence for an isotope effect within the limits of experimental uncertainty.
TL;DR: In this article, Kolmogorov's law of the iterated logarithm is extended to the martingale case, which is a special case of the regular case.
Abstract: SummaryKolmogorov's law of the iterated logarithm is extended to the martingale case.