Showing papers by "University of Chicago published in 1975"
TL;DR: This paper studied both the initial and aftermarket performance on newly issued common stocks which were offered to the public during the 1960s and found that average initial performance is positive (11.4 percent), while the distribution of returns is skewed so that the subscriber of a single random new issue offering has about an equal chance for gain or loss.
1,428 citations
TL;DR: It is concluded that the shape of the iodopsin absorption spectrum provides a reasonable basis for computation of absorption spectra of the middleand long-wavelength sensitive cone pigments and that long-Wavelength sensitive cones of deuteranopes.
1,263 citations
Book•
01 Jan 1975918 citations
03 Jul 1975-Philosophical transactions - Royal Society. Mathematical, physical and engineering sciences
TL;DR: For the Korteweg-de-vries model equation, existence, uniqueness, regularity, and continuous dependence results are established for both the pure initial value problem and the continuous dependence model equation as mentioned in this paper.
Abstract: For the Korteweg-de Vries equation u t + u x + u u x + u x x x = 0 , existence, uniqueness, regularity and continuous dependence results are established for both the pure initial-value problem (posed on -∞ x x ⩽ l with periodic initial data). The results are sharper than those obtained previously in that the solutions provided have the same number of L 2 -derivatives as the initial data and these derivatives depend continuously on time, as elements of L 2 . The same equation with dissipative and forcing terms added is also examined. A by-product of the methods used is an exact relation between solutions of the Korteweg-de Vries equation and solutions of an alternative model equation recently studied by Benjamin, Bona & Mahony (1972). It is proven that in the long-wave limit under which these equations are generally derived, the solutions of the two models posed for the same initial data are the same. In the process of carrying out this programme, new results are obtained for the latter model equation.
715 citations
TL;DR: In this paper, the authors compared the predictive ability of standard linear regression and simple unit weighting schemes, and found that unit weights are a viable alternative to standard regression in certain situations and not greatly inferior in others.
648 citations
TL;DR: The quasi-normal modes of a black hole represent solutions of the relevant perturbation equations which satisfy the boundary conditions appropriate for purely outgoing (gravitational) waves at infinity and purely ingoing waves at the horizon as discussed by the authors.
Abstract: The quasi-normal modes of a black hole represent solutions of the relevant perturbation equations which satisfy the boundary conditions appropriate for purely outgoing (gravitational) waves at infinity and purely ingoing waves at the horizon. For the Schwarzschild black hole the problem reduces to one of finding such solutions for a one-dimensional wave equation (Zerilli's equation) for a potential which is positive everywhere and is of short-range. The notion of quasi-normal modes of such one-dimensional potential barriers is examined with two illustrative examples; and numerical solutions for Zerilli's potential are obtained by integrating the associated Riccati equation.
508 citations
TL;DR: In this article, the invariant cross section of a proton-nucleus collision with a tungsten (W) target at incident proton energies of 200, 300, and 400 GeV was measured as a function of transverse momentum.
Abstract: We have measured, as a function of transverse momentum (${p}_{\ensuremath{\perp}}$), the invariant cross section $\frac{\mathrm{Ed}\ensuremath{\sigma}}{{d}^{3}p}$ for the production of ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$, ${K}^{\ifmmode\pm\else\textpm\fi{}}$, $p$, $\overline{p}$, $d$, and $\overline{d}$ in proton collisions with a tungsten (W) target at incident proton energies of 200, 300, and 400 GeV. The measurements were made in the region of 90\ifmmode^\circ\else\textdegree\fi{} in the c.m. system of the incident proton and a single nucleon at rest. Measurements were also made with 300-GeV protons incident on Be, Ti, and W targets of equal interaction length. These $p$-nucleus measurements, which show a strong dependence on atomic number at high ${p}_{\ensuremath{\perp}}$, were used to extract effective proton-nucleon cross sections by extrapolation to atomic number unity. At large values of the scaling variable ${x}_{\ensuremath{\perp}}=2\frac{{p}_{\ensuremath{\perp}}}{\sqrt{s}}$, where $s$ is the square of the c.m. energy, the pion data are found to be well represented by the expression ${(\sqrt{s})}^{\ensuremath{-}n}{e}^{\ensuremath{-}{\mathrm{ax}}_{\ensuremath{\perp}}}$, with $n=11.0\ifmmode\pm\else\textpm\fi{}0.4$ and $a=36.0\ifmmode\pm\else\textpm\fi{}0.4$. ${x}_{\ensuremath{\perp}}l0.35$, where similar measurements have been made at the CERN ISR, our data are in good agreement with the ISR data.
456 citations
TL;DR: The authors examined the effects of semantic structure on simple inductive judgments about category members and found that if subjects learn that an unknown property is possessed by a typical species (i.e., one that shares many of its properties with other category members), they are more likely to generalize than if the same fact had been learned about an atypical species.
442 citations
TL;DR: The restoration of disrupted words to their original form in a sentence shadowing task is dependent upon semantic and syntactic context variables, thus demonstrating an on-line interaction between the structural and the lexical and phonetic levels of sentence processing.
Abstract: The restoration of disrupted words to their original form in a sentence shadowing task is dependent upon semantic and syntactic context variables, thus demonstrating an on-line interaction between the structural and the lexical and phonetic levels of sentence processing.
427 citations
TL;DR: A description of the host phase from the Allende C3V chondrite and a mass spectrometric study of the five noble gases in this phase is presented in this paper.
Abstract: A description is presented for the isolation and characterization of the host phase from the Allende C3V chondrite and a mass spectrometric study of the five noble gases in this phase It is though that the Xe component may have been produced by spontaneous fission of an extinct superheavy element The fission Xe resides in a minor fraction comprising 05% of the meteorite The fraction consists of chromite, an unknown Cr, Fe-mineral, and amorphous carbon The gas components and the progenitor of the fission Xe may have been trapped in these minerals when they formed from the solar nebula
364 citations
TL;DR: In this paper, the theory for the stability of solitary waves developed by T. B. Benjamin was improved and applied equally to the Kortewegde Vries equation and to an alternative model equation for the propagation of long waves in nonlinear dispersive media.
Abstract: Improvements are made on the theory for the stability of solitary waves developed by T. B. Benjamin. The results apply equally to the Kortewegde Vries equation and to an alternative model equation for the propagation of long waves in nonlinear dispersive media.
TL;DR: While performance varied with altered brain function, complaint was related to level of depression, regardless of performance, andaggerated memory complaint was considered one manifestation of a general pattern of discrpant reporting of symptoms by depressed persons.
Abstract: To clarify the role of memory impairment in the aged as a normal or psychopathological phenomenon, 153 persons 50-years-old and over with varying degrees of depression and altered brain function were compared for their complaints about memory and actual performance on a series of memory tests. It was found that while performance varied with altered brain function, complaint was related to level of depression, regardless of performance. Exaggerated memory complaint was considered one manifestation of a general pattern of discrepant reporting of symptoms by depressed persons, and apparently related to an underlying personality factor. The complaint of superiority of remote over recent memory was not substantiated empirically, but was considered part of the pattern of stereotyped language and attitudes characteristic of depressed persons.
TL;DR: It is indicated that there are four distinct structural forms of HSV DNA which differ only in the relative orientations of two subregions, designated L and S, which have novel implications with regard to the genetic map and the mode of replication and evolution of herpes simples viruses.
Abstract: Intact DNA molecules extracted from HSV-1 (herpes simplex virus 1, human herpes virus 1) strain MP virions have a molecular weight of approximately 97 X 10(6), but cleavage with the HinIII restriction enzyme yields fourteen fragments with summed molecular weights of 160 X 10(6). Six "major" fragments occur once in every molecule in the population and account for 60% of the genetic information. Four "minor" fragments are present in amounts equivalent to one copy for every two genomes (0.5 molar ratio) and the other four occur only once in every four molecules (0.25 molar ratio). The minor fragments can be arranged into four equimolar sets, each with summed molecular weights that account for the remaining 40% of the genome. Treatment with lambda 5' exonuclease revealed that all molecules contain 0.5 molar ratio fragments at both termini. These observations and the results of similar analyses of the EcoRI and double HinIII/EcoRI digests indicate that there are four distinct structural forms of HSV DNA which differ only in the relative orientations of two subregions, designated L and S. The L and S segments consist of 82 and 18% of the sequences, respectively, and each has inverted terminally redundant regions that correspond to the internal duplications observed by electron microscopy. The DNA from other strains of HSV-1 and 2 also consists of equal proportions of all four possible permutations of the L and S segments. These unusual features of HSV DNA molecules have novel implications with regard to the genetic map and the mode of replication and evolution of herpes simples viruses.
TL;DR: In this article, it was shown that magnetic fields can be retained for long periods of time in the stable radiative region beneath the convective zone, but unfortunately the solar dynamo cannot function there because turbulent diffusion is an essential part of its operation.
Abstract: The magnetic field appearing as bipolar magnetic regions at the surface of the sun represents the lines of force from a general azimuthal field of the order of 100 gauss somewhere beneath the surface. The amplification time, as a consequence of the nonuniform rotation, is of the order of 10 years. But magnetic buoyancy brings the azimuthal field up through much of the convective zone in a time rather less than 10 years, raising the question of where the azimuthal field can be retained long enough to be amplified. We show that magnetic fields can be retained for long periods of time in the stable radiative region beneath the convective zone, but unfortunately the solar dynamo cannot function there because turbulent diffusion is an essential part of its operation. The only possible conclusion appears to be that the dynamo operates principally in the very lowest levels of the convective zone at depths of 150,000 km or more, where the gas density is 0.1 g/cu cm, and the fields are limited to 50 gauss.
TL;DR: The necessary theoretical framework to make predictions concerning relevant quantities of elemental analysis such as the minimum detectable mass (MDM) and mimimum detectable mass fraction (MMF) and the results of these calculations for thin specimens indicate a potential reduction in the MDM and the MMF through the use of transmitted energy loss electrons rather than X-rays.
TL;DR: In this paper, it was shown that the conserved magnetic charge discovered by ’t Hooft in non−Abelian gauge theories with spontaneous symmetry breaking is not associated with the invariance of the action under a symmetry group.
Abstract: It is shown that the conserved magnetic charge discovered by ’t Hooft in non−Abelian gauge theories with spontaneous symmetry breaking is not associated with the invariance of the action under a symmetry group. Rather, it is a topological characteristic of an isotriplet of Higgs fields in a three−dimensional space: the Brouwer degree of the mapping between a large sphere in configuration space and the unit sphere in field space provided by the normalized Higgs field ? a = φ a (φ b φ b )−1/2. The use of topological methods in determining magnetic charge configurations is outlined. A peculiar interplay between Dirac strings and zeros of the Higgs field under gauge transformations is pointed out. The monopole−antimonopole system is studied.
TL;DR: In this paper, the authors extended the analysis of particle creation by black holes by explicitly obtaining the expression for the quantum mechanical state vector ψ which results from particle creation starting from the vacuum during gravitational collapse.
Abstract: Hawking's analysis of particle creation by black holes is extended by explicitly obtaining the expression for the quantum mechanical state vector ψ which results from particle creation starting from the vacuum during gravitational collapse. (Hawking calculated only the expected number of particles in each mode for this state.) We first discuss the quantum field theory of a Hermitian scalar field in an external potential or in a curved but asymptotically flat spacetime with no horizon present. In agreement with previously known results, we find that we are led to a unique quantum scattering theory which is completely well behaved mathematically provided a certain condition is satisfied by the operators which describe the scattering of classical positive frequency solutions. In terms of these operators we derive the expression for the state vector describing particle creation from the vacuum, and we prove that S-matrix is unitary. Making the necessary modification for the case when a horizon is present, we apply this theory for a massless Hermitian scalar field to get the state vector describing the steady state emission at late times for particle creation during gravitational collapse to a Schwarzschild black hole. There is some ambiguity in the theory in this case arising from freedom involved in defining what one means by “positive frequency” at the future event horizon. However, it is proven that the expression for the density matrix formed from ψ describing the emission of particles to infinity is independent of this choice, and thus unambiguous predictions for the results of all possible measurements at infinity are obtained. We find that the state vector describing particle creation from the vacuum decomposes into a simple product of state vectors for each individual mode. The density matrix describing emission of particles to infinity by this particle creation process is found to be identical to that of black body emission. Thus, black hole emission agrees in complete detail (i.e., not only in expected number of particles) with black body emission.
TL;DR: The data from this study indicate that intraperitoneal insufflation produces serious hemodynamic alterations which are manifested by low cardiac output and elevated total peripheral resistance, and directly measured right atrial pressure cannot be used clinically as an indicator of venous return to the heart since it reflects a composite of pleural and intra-abdominal insUFFlation pressures.
Abstract: Cardiovascular changes caused by intraperitoneal insufflation with CO2 or N2O were measured in 15 mongrel dogs. Moderate progressive increases in intra-abdominal pressure (to 40 mm Hg) with either gas produced increases in mean arterial, right atrial, pleural, and femoral-vein pressures. Cardiac out
TL;DR: In this article, the authors consider an economy in which individuals receive both a fixed endowment of real income and nominal transfer payments in the form of bills printed by the government during each period of life and develop a simple model which sharpens understanding of the forces that determine the equilibrium path of the price level and money income over time.
TL;DR: In this article, the authors propose a principle for maximally concentrating radiation onto a tube receiver of general shape, and give a general prescription for designing concentrators appropriate to such tube receivers.
TL;DR: In this paper, two types of white, coarse-grained, Ca-Al-rich inclusions were found in Allende and Grosnaja, New Mexico: Type A inclusions contain 80-85 per cent melilite, 15-20 per cent spinel, 1-2 per cent perovskite and rare plagioclase.
TL;DR: Examined are extant "personality theories" having to do with children's social behavior, adult behavior in small groups, maternal socialization practices, and psychopathology, which are shown to be no more than statements about how respondents (and psychologists) classify things as alike in meaning.
Abstract: Doubts are raised as to the extent of "applicability of the conceptualization that "personality" consists "of more or less stable internal factors that make one person's behavior consistent from one time to another, and different from the behavior other people would manifest in comparable situations". This is done by demonstrating the questionable validity of much of the extant empirical support for the "personality" concept. Respondents on interpersonal checklists, personality inventories and questionnaire interviews are shown to unwittingly sub stitute a theory of conceptual likenesses for a description of behavioral co-occurrences. Considerations about similarity are confounded with judgments about probability to such an extent that items alike in concept are inferred to be behaviorally characteristic of the same person even when, as is typically the case, conceptual relationships among items do not correspond to the actual behavioral relationships among items. Examined are extant "personality theories" having to do with children's social behavior, adult behavior in small groups, maternal socialization practices, and psychopathology. These "theories" are shown to be no more than statements about how respondents (and psychologists) classify things as alike in meaning.
TL;DR: A chondrosarcoma grown in rats was found to produce a single kind of collagen, which was identified as a type II collagen, the cartilage specific protein.
TL;DR: Although azathioprine does not confer dramatic benefit upon patients with chronic ulcerative colitis who require steroids, it does permit reduction of steroid dosage without apparent worsening of the disease.
TL;DR: The phase relations for this join provide part of the essential framework of the model peridotite system CaO-MgO-SiO_8-CO_2-H_2O, which has particular application to the origin of carbonatitic and kimberlitic magmas.
TL;DR: In this paper, the properties of the entire spectra have been interpreted in terms of a few parameters, such as quantum defects and oscillator-strength densities, which vary slowly with the excitation energy.
Abstract: The properties of entire spectra—specifically, the line positions and transition probabilities of perturbed series and of their adjoining continua as well as autoionization line profiles and related collision cross sections—have been interpreted in terms of a few parameters, such as quantum defects and oscillator-strength densities, which vary slowly with the excitation energy. By use of Seaton’s quantum-defect theory, the concept of separate configurations is replaced by the more comprehensive concept of channels. Alternative sets of channels are considered, related by a frame transformation whose construction is a main goal of the analysis of each spectrum. Concepts and procedures employed for these purposes since 1969 are summarized and restated here. Reference is made to extension of the treatment to negative ions, and to the direct ab initio calculation of the channel parameters to be compared with experimental results. Illustrative results are presented, as well as a guide to relevant literature.
Patent•
15 Sep 1975TL;DR: In this article, non-imaging systems and devices for collection and concentration of electromagnetic energy and particularly solar energy including one or more longitudinally-extending, generally trough-shaped bodies having curving inner reflective walls for concentration of energy from a relatively large entrance aperture toward a relatively small exit aperture.
Abstract: Disclosed are non-imaging systems and devices for collection and concentration of electromagnetic energy and particularly solar energy including one or more longitudinally-extending, generally trough-shaped bodies having curving inner reflective walls for concentration of energy from a relatively large entrance aperture toward a relatively small exit aperture. Solar energy concentrators of the invention include energy traps and collect and concentrate substantial amounts of direct solar energy, even at solstice, without substantial diurnal tracking.
TL;DR: The results are that when the recombination fraction between the loci is of the same order of magnitude as the selection coefficients or smaller, then linkage is important in determining the gene frequencies and a substantial amount of linkage disequilibrium is present in the cline.
Abstract: A model of gene flow and selection in two linked loci is analyzed. The problems considered are the effects of linkage on the clines in frequencies at the two loci and the role of gene flow in producing linkage disequilibrium between the loci. Also, the possible significance of linkage as a mechanism for permitting a population of "track" spatial changes in the environment is considered. The results are that when the recombination fraction between the loci is of the same order of magnitude as the selection coefficients or smaller, then linkage is important in determining the gene frequencies and a substantial amount of linkage disequilibrium is present in the cline. Depending on the spatial pattern of selection on the two loci, linkage can either decrease or increase a population's response to local selection.