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Showing papers by "California Institute of Technology published in 1971"


Journal ArticleDOI
TL;DR: Three mutants have been isolated in which the normal 24-hour rhythm is drastically changed and all these mutations appear to involve the same functional gene on the X chromosome.
Abstract: Three mutants have been isolated in which the normal 24-hour rhythm is drastically changed. One mutant is arrhythmic; another has a period of 19 hr; a third has a period of 28 hr. Both the eclosion rhythm of a population and the locomotor activity of individual flies are affected. All these mutations appear to involve the same functional gene on the X chromosome.

2,161 citations


Journal ArticleDOI
TL;DR: δ 13C/12C ratios have been determined for plant tissue from 104 species representing 60 families and photosynthetic fractionation leading to such values is discussed.
Abstract: 13C/12C ratios have been determined for plant tissue from 104 species representing 60 families. Higher plants fall into two categories, those with low δPDBI13C values (—24 to —34‰) and those with high δ 13C values (—6 to —19‰). Algae have δ 13C values of —12 to —23‰. Photosynthetic fractionation leading to such values is discussed.

1,943 citations


Journal ArticleDOI
TL;DR: In this paper, the properties of large amplitude microscale Alfven waves in interplanetary medium were investigated using plasma and magnetic field data from Mariner 5. But the results were limited to a single-dimensional image.
Abstract: Dynamic nonshock properties of large amplitude microscale Alfven waves in interplanetary medium, using plasma and magnetic field data from Mariner 5

1,714 citations


Journal ArticleDOI
TL;DR: In this paper, a theoretical justification for an empirical boundary condition proposed by Beavers and Joseph is given for non-homogeneous porous medium, and the statistical approach is checked by using it to derive Einstein's law for the viscosity of dilute suspensions.
Abstract: A theoretical justification is given for an empirical boundary condition proposed by Beavers and Joseph [1]. The method consists of first using a statistical approach to extend Darcy's law to non homogeneous porous medium. The limiting case of a step function distribution of permeability and porosity is then examined by boundary layer techniques, and shown to give the required boundary condition. In an Appendix, the statistical approach is checked by using it to derive Einstein's law for the viscosity of dilute suspensions.

1,139 citations


Journal ArticleDOI
TL;DR: In this paper, a numerical method was proposed to solve the problem of balloon bubble collapse near a plane solid wall, using finite time steps and an iterative technique for applying the boundary conditions at infinity directly to the liquid at a finite distance from the free surface.
Abstract: Vapor bubble collapse problems lacking spherical symmetry are solved here using a numerical method designed especially for these problems. Viscosity and compressibility in the liquid are neglected. The method uses finite time steps and features an iterative technique for applying the boundary conditions at infinity directly to the liquid at a finite distance from the free surface. Two specific cases of initially spherical bubbles collapsing near a plane solid wall were simulated: a bubble initially in contact with the wall, and a bubble initially half its radius from the wall at the closest point. It is shown that the bubble develops a jet directed towards the wall rather early in the collapse history. Free surface shapes and velocities are presented at various stages in the collapse. Velocities are scaled like (Δp/ρ)^1/2 where ρ is the density of the liquid and Δp is the constant difference between the ambient liquid pressure and the pressure in the cavity. For Δp/ρ = 10^6 (cm/sec)^2 ~ 1 atm./density of water the jet had a speed of about 130 m/sec in the first case and 170 m/sec in the second when it struck the opposite side of the bubble. Such jet velocities are of a magnitude which can explain cavitation damage. The jet develops so early in the bubble collapse history that compressibility effects in the liquid and the vapor are not important.

890 citations


Journal ArticleDOI
TL;DR: The structure of crystalline horse heart ferricytochrome c has been determined by x-ray methods to a resolution of 2.8 A, and the results have been extended to obtain the structure of bonito cy tochrome c as well.

789 citations


Journal ArticleDOI
TL;DR: The amplitude-constrained capacity of a scalar Gaussian channel is shown to be achieved by a unique discrete random variable taking on a finite number of values.
Abstract: The amplitude-constrained capacity of a scalar Gaussian channel is shown to be achieved by a unique discrete random variable taking on a finite number of values. Necessary and sufficient conditions for the distribution of this random variable are obtained. These conditions permit determination of the random variable and capacity as a function of the constraint value. The capacity of the same Gaussian channel subject, additionally, to a nontrivial variance constraint is also shown to be achieved by a unique discrete random variable taking on a finite number of values. Likewise, capacity is determined as a function of both amplitude- and variance-constraint values.

542 citations


Journal ArticleDOI
TL;DR: The x-ray structure analysis of ferricytochromec shows the reasons for the evolutionary conservatism of hydrophobic and aromatic side chains, lysines, and glycines, as well as the observed rates of change in fibrinopeptides, the globins, cy tochromec, and several enzymes, interpreted in terms of the proteins' biological roles.
Abstract: The x-ray structure analysis of ferricytochromec shows the reasons for the evolutionary conservatism of hydrophobic and aromatic side chains, lysines, and glycines, which had been observed from comparisons of amino acid sequences from over 30 species. It also shows that the negative character of one portion of the molecular surface is conserved, even though individual acidic side chains are not, and that positive charges are localized around two hydrophobic “channels” leading from the interior to the surface.

482 citations



Journal ArticleDOI
TL;DR: In this paper, a relativistic equation to represent the symmetric quark model of hadrons with harmonic interaction is used to define and calculate matrix elements of vector and axial-vector currents.
Abstract: A relativistic equation to represent the symmetric quark model of hadrons with harmonic interaction is used to define and calculate matrix elements of vector and axial-vector currents. Elements between states with large mass differences are too big compared to experiment, so a factor whose functional form involves one arbitrary constant is introduced to compensate this. The vector elements are compared with experiments on photoelectric meson production, Kl3 decay, and ω→πγ. Pseudoscalar-meson decay widths of hadrons are calculated supposing the amplitude is proportional (with one new scale constant) to the divergence of the axial-vector current matrix elements. Starting only from these two constants, the slope of the Regge trajectories, and the masses of the particles, 75 matrix elements are calculated, of which more than 3/4 agree with the experimental values within 40%. The problems of extending this calculational scheme to a viable physical theory are discussed.

425 citations


Journal ArticleDOI
TL;DR: In this paper, an approximate serpentine-magnetite geothermometer curve was constructed by extrapolation of observed O18 fractionations between coexisting chlorites and Fe-Ti oxides in low-grade pelitic schists whose isotopic temperatures are known from the quartz-muscovite O18 geithermometer.
Abstract: Five lizardite-chrysotile type serpentinites from California, Guatemala and the Dominican Republic show oxygen isotope fractionations of 15.1 to 12.9 per mil between coexisting serpentine and magnetite (δO18 magnetite=−7.6 to −4.6 per mil relative to SMOW). Nine antigorites (mainly from Vermont and S. E. Pennsylvania) show distinctly smaller fractionations of 8.7 to 4.8 per mil (δO18 magnetite=−2.6 to +1.7 per mil). Two lizardite and chrysotile serpentinites dredged from the Mid-Atlantic Ridge exhibit fractionations of 10.0 and 12.4 per mil (δO18 magnetite=−6.8 and −7.9 per mil, respectively), whereas an oceanic antigorite shows a value of 8.2 per mil (δO18 magnetite=−6.2). These data all clearly indicate that the antigorites formed at higher temperatures than the chrysotilelizardites. Electron microprobe analyses of magnetites from the above samples show that they are chemically homogeneous and essentially pure Fe3O2. However, some magnetites from certain other samples that show a wide variation of Cr content also give very erratic oxygen isotopic results, suggesting non-equilibrium. An approximate serpentine-magnetite geothermometer curve was constructed by (1) extrapolation of observed O18 fractionations between coexisting chlorites and Fe-Ti oxides in low-grade pelitic schists whose isotopic temperatures are known from the quartz-muscovite O18 geothermometer, and (2) estimates of the O18 fractionation factor between chlorite and serpentine (assumed to be equal to unity). This serpentine-magnetite geothermometer suggests approximate equilibrium temperatures as follows: continental lizardite-chrysotile, 85° to 115° C; oceanic lizardite and chrysotile, 130° C and 185° C, respectively; oceanic antigorite, 235° C; and continental antigorites, 220° to 460° C.

Journal ArticleDOI
TL;DR: In this article, the authors used the exact analytical solution for the two-dimensional SH-wave propagation in and around an elastic inclusion whose cross section corresponds to one half of an ellipse, and examined those aspects of the resulting ground motion that are of special interest for earthquake engineering and strong-motion seismology.
Abstract: By using the exact analytical solution for the two-dimensional SH-wave propagation in and around an elastic inclusion whose cross section corresponds to one half of an ellipse, we have examined those aspects of the resulting ground motion that are of special interest for earthquake engineering and strong-motion seismology. Computed amplitudes and phases of periodic ground motion display complicated wave-interference phenomena that lead to nearly-standing wave patterns, abrupt changes in the amplification of incident motions along the free surface of the alluvial valley and strong dependence of the overall motions on the incidence angle of SH waves. By comparing the amplification patterns derived from the exact model with the amplifications computed on the basis of an equivalent single-layer model excited by the vertically incident shear waves, we have demonstrated that this approximate representation may lead to meaningful results only if the wavelength of incident waves is longer than the characteristic dimension of the alluvial valley. Although simple, we expect that the model presented in this paper might explain qualitatively the vibrations of some alluvial valleys excited by SH components of strong ground motion.

Journal ArticleDOI
TL;DR: In this paper, the main features of this undulatory mode of propulsion are discussed for the case of large Reynolds number, based on the principle of energy conservation, and the general problem of a two-dimensional flexible plate, swimming at arbitrary, unsteady forward speeds, is solved by applying the linearized inviscid flow theory.
Abstract: The most effective movements of swimming aquatic animals of almost all sizes appear to have the form of a transverse wave progressing along the body from head to tail. The main features of this undulatory mode of propulsion are discussed for the case of large Reynolds number, based on the principle of energy conservation. The general problem of a two-dimensional flexible plate, swimming at arbitrary, unsteady forward speeds, is solved by applying the linearized inviscid flow theory. The large-time asymptotic behaviour of an initial-value harmonic motion shows the decay of the transient terms. For a flexible plate starting with a constant acceleration from at rest, the small-time solution is evaluated and the initial optimum shape is determined for the maximum thrust under conditions of fixed power and negligible body recoil.

Book ChapterDOI
01 Jan 1971
TL;DR: In this paper, a difference scheme for parabolic mixed initial-boundary value problems in one space dimension is presented, which is unconditionally stable and has second order accuracy with non-uniform nets.
Abstract: This chapter discusses a new difference scheme for parabolic mixed initial-boundary value problems in one space dimension. The scheme has a number of very desirable features. It is simple, easy to program, and efficient. It is unconditionally stable and has second order accuracy with nonuniform nets. Richardson or h → 0 extrapolation is valid and yields two orders of accuracy improvement per extrapolation (with nonuniform nets). It is A-stable as well, that is, if the exact solution decays in time, so does the numerical scheme, with approximately the same rate; the data, coefficients, and solution need only be piecewise smooth and all the above remain valid. The method is also applicable to parabolic systems, to nonlinear parabolic equations, and even to some hyperbolic systems with special properties. The chapter presents the method, indicates the error estimates, h → 0 extrapolation and discusses an efficient algorithm for its application to the problem.

Journal ArticleDOI
TL;DR: In this article, the authors used the Ar-40/Ar-39 dating technique on eight samples of Apollo 14 rocks (14053, 14310), breccia fragments (14321), and soil fragments (14001, 14167).

Journal ArticleDOI
TL;DR: All of the nearly 200 deletion mutants studied are defective in the ability to promote recombination in recombinationless host bacteria and fall into three major classes with respect to their integration behavior in different host strains.

Journal ArticleDOI
TL;DR: Under the best conditions, single ganglion cells of the cat's retina give one extra impulse for less than 3 quanta at the cornea, suggesting that when a single quantum is absorbed in the retina several extra impulses must be initiated.

Journal ArticleDOI
TL;DR: In this paper, the authors considered the high-energy scattering and astrophysics applications of this model and obtained a solution with a <-5/2 which satisfies the bootstrap condition exactly in the high mass limit.
Abstract: The hadron is considered to be a compound with two or more constituents circulating freely in a box of radius ≈10^-13 cm. The density of hadron levels, ρ (m), is estimated from the number of states in the box (statistical condition) and is also required to be consistent with the spectrum of constituents, which are assumed to be the hadrons themselves (bootstrap condition). This type of model was first considered by Hagedorn, who obtained a solution of form ρ m∼cm^ae^(bm) with a=-5/2 which satisfied the bootstrap condition asymptotically to within a power of m. We obtain a solution with a<-5/2 which satisfies the bootstrap condition exactly in the high-mass limit. The constituents in the box are distributed with probability P(n)=(ln2)^(n-1)/(n-1)!; i.e., an average high-mass resonance decays (in the first generation of its decay chain) to two hadrons (69% probability) or three (24% probability). We also review briefly the thermodynamic applications of this model to high-energy scattering and astrophysics.

Book ChapterDOI
TL;DR: In this article, the authors present modeling in nonlinear random vibrations by Markov processes, and discuss the basic theory of stochastic processes and its applications and solution techniques, and the difficulties involved in modeling non-linear random vibrational effects.
Abstract: Publisher Summary Random vibration analysis of mechanical systems has become an important subject in recent years, principally because of advances in high speed flight. To design structures and equipment that will survive the randomly fluctuating loads caused by the flow of turbulent air or the efflux of jet or rocket engines, it has become necessary to develop a theory capable of analyzing the effect of such fluctuating loads on structures and equipment. Many of the techniques developed for the analysis of random excitation of nonlinear control systems are applicable to the analysis of nonlinear random vibrations, and conversely many of the techniques developed in the theory of nonlinear random vibrations are equally applicable to problems in communication theory and electronics. The chapter presents modeling in nonlinear random vibrations by Markov processes. The chief reason for adopting the idealized model of a system of differential equations excited by white noise is that the computations are much simpler in this case. One of the difficulties involved in modeling nonlinear random vibrations by Markov processes is that—one is restricted to quasi-linear systems. In the subsequent development of the theory, no distinction has been made between the physical nonlinearity and the mathematical model of that nonlinearity. Further, the chapter also discusses the basic theory of stochastic processes and its applications and solution techniques.

Journal ArticleDOI
TL;DR: In this paper, a theory termed the "arbitrary-shape harbour" theory is developed, where the solution of the Helmholtz equation is formulated as an integral equation which is then approximated by a matrix equation.
Abstract: Wave-induced oscillations in harbours of constant depth but arbitrary shape in the horizontal plane connected to the open-sea are investigated both theoretically and experimentally. A theory termed the ‘arbitrary-shape harbour’ theory is developed. The solution of the Helmholtz equation is formulated as an integral equation which is then approximated by a matrix equation. The final solution is obtained by equating, at the harbour entrance, the wave amplitudes and their normal derivatives obtained from the solutions for the regions outside and inside the harbour. Special solutions using the method of separation of variables for the region inside circular and rectangular harbours are also obtained. Experiments were conducted to verify the theories. Four specific harbours were investigated: two circular harbours with 10° and 60° openings respectively, a rectangular harbour, and a model of the East and West Basins of Long Beach Harbour, California. In each case, the theoretical results agreed well with the experimental data.


Journal ArticleDOI
TL;DR: In this article, the isotopic equilibrium is approximately attained between the weathering products and their coexisting waters in Quaternary soils of the United States, and it is shown that isotopic fractionation factors estimated from the data for kaolinite and montmorillonite at earth surface temperatures are very similar, with α clay -H 2 O hy ≈ 0.970 and α clay- H 2 O ox ≈ 1.027.

Journal ArticleDOI
TL;DR: In this paper, the spectrum and energy of a point test particle falling radially into a Schwarzschild black hole was estimated, and the total energy radiated was about $0.0104m{c}^{2}(\frac{m}{M}), 4 to 6 times larger than previous estimates; the energy was distributed among multipoles according to the empirical law.
Abstract: We have computed the spectrum and energy of gravitational radiation from a "point test particle" of mass $m$ falling radially into a Schwarzschild black hole of mass $M\ensuremath{\gg}m$. The total energy radiated is about $0.0104m{c}^{2}(\frac{m}{M})$, 4 to 6 times larger than previous estimates; the energy is distributed among multipoles according to the empirical law ${E}_{2l\ensuremath{-}\mathrm{p}\mathrm{o}\mathrm{l}\mathrm{e}}\ensuremath{\approx}(\frac{0.44{m}^{2}{c}^{2}}{M}){e}^{\ensuremath{-}2l}$; and the total spectrum peaks at an angular frequency $\ensuremath{\omega}=\frac{0.32{c}^{3}}{\mathrm{GM}}$.

Journal ArticleDOI
TL;DR: The observation that the fraction of the heteroduplex observed as double-stranded decreases with an increase in denaturing conditions indicates that the DNA's of T7 and T3 have extensive sequences of partial homology.

Journal ArticleDOI
TL;DR: In this paper, the neutrino spin precession effects in the magnetic field of the Sun are considered as an explanation of the outcome of Davis' solar neutrinos experiments. But, the value for the Neutrino magnetic moment evaluated under these theoretically anomalous circumstances is still so small that only the largest possible estimate for magnetic field strength in the Sun's interior would cause the required effect.
Abstract: Neutrino spin precession effects in the magnetic field of the Sun are considered as an explanation of the outcome of Davis' solar neutrino experiments. Theoretically, it is possible to account for a neutrino magnetic moment only as the result of the interaction of the electromagnetic field with charged particles into which the neutrino can transform virtually. The currently accepted theory of weak interactions (the two component neutrino andV-A interactions) forbids a resulting magnetic moment interaction with the electromagnetic field for all such virtual processes. Modifications of this theory are considered to find out whether an appreciable precession effect is permitted within the experimentally established limits. It is found that the value for the neutrino magnetic moment evaluated under these theoretically anomalous circumstances is still so small that only the largest possible estimate for the magnetic field strength in the Sun's interior would cause the required effect.

Journal ArticleDOI
TL;DR: This note seeks to evaluate the self-propulsion of a micro-organism, in a viscous fluid, by sending a helical wave down its flagellated tail by determining the power required for propulsion by means of helical waves, and the hydromechanical efficiency η is defined.
Abstract: This note seeks to evaluate the self-propulsion of a micro-organism, in a viscous fluid, by sending a helical wave down its flagellated tail. An explanation is provided to resolve the paradoxical phenomenon that a micro-organism can roll about its longitudinal axis without passing bending waves along its tail (Rothschild 1961, 1962; Bishop 1958; Gray 1962). The effort made by tho organism in so doing is not torsion, but bending simultaneously in two mutually perpendicular planes. The mechanical model of the micro-organism adopted for the present study consists of a spherical head of radius ɑ and a long cylindrical tail of cross-sectional radius b, along which a helical wave progresses distally. Under the equilibrium condition at a constant forward speed, both the net force and net torque acting on the organism are required to vanish, yielding two equations for the velocity of propulsion, U, and the induced angular velocity, Ω, of the organism. In order that this type of motion can be realized, it is necessary for the head of the organism to exceed a certain critical size, and some amount of body rotation is inevitable. In fact, there exists 1m optimum head-tail ratio ɑ/bat which the propulsion velocity U reaches a maximum, holding the other physical parameters fixed. The power required for propulsion by means of helical waves is determined, based on which a hydromechanical efficiency η is defined. When the head-tail ratio ɑ/b assumes its optimum value and when b is very small compared with the wavelength λ, η ≃ Ω/ω approximately (Ω being the induced angular velocity of the head, ω the circular frequency of the helical wave). This η reaches a maximum at kh ≃ 0.9 (k being the wavenumber 2π/λ, and h the amplitude of the helical wave). In the neighbourhood of kh = 0.9, the optimum head-tail ratio varies in the range 15 < a/b < 40, the propulsion velocity in 0.08 < U/c < 0.2 (c = ω/k being the wave phase velocity), and the efficiency in 0.14 < η < 0.24, as kb varies over 0.03 < kb < 0.2, a range of practical interest. Furthermore, a comparison between the advantageous features of planar and helical waves, relative to each other, is made in terms of their propulsive velocities and power consumptions.

Journal ArticleDOI
TL;DR: Lunar chronology and evolution from Rb and Sr internal isochrons on Apollo 11 and 12 crystalline rock samples were studied in this paper, where the inner isochron was found to be a Rb-Sr internal isomer.

Journal ArticleDOI
TL;DR: An adaptive variable length coding system is presented, developed primarily for the proposed Grand Tour missions, but many features of this system clearly indicate a much wider applicability.
Abstract: An adaptive variable length coding system is presented Although developed primarily for the proposed Grand Tour missions, many features of this system clearly indicate a much wider applicability Using sample to sample prediction, the coding system produces output rates within 025 bit/picture element (pixel) of the onedimensional difference entropy for entropy values ranging from 0 to 8 bit/pixel This is accomplished without the necessity of storing any code words Performance improvements of 05 bit/pixel can be simply achieved by utilizing previous line correlation A Basic Compressor, using concatenated codes, adapts to rapid changes in source statistics by automatically selecting one of three codes to use for each block of 21 pixels The system adapts to less frequent, but more dramatic, changes in source statistics by adjusting the mode in which the Basic Compressor operates on a line-to-line basis Furthermore, the compression system is independent of the quantization requirements of the pulse-code modulation system

Journal ArticleDOI
19 Mar 1971-Science
TL;DR: Seismology and solid state physics place strong constraints on the constitution of the earth's interior, resulting in strong limits on the strength of the volcano's constitution.
Abstract: Seismology and solid state physics place strong constraints on the constitution of the earth's interior.

15 May 1971
TL;DR: Mathematical formulation of Double Precision Orbit Determination Program /DPODP/ for lunar and planetary mission spacecraft trajectories is presented in this article, where the authors consider the case of two spacecraft.
Abstract: Mathematical formulation of Double Precision Orbit Determination Program /DPODP/ for lunar and planetary mission spacecraft trajectories