Showing papers by "University of Southern California published in 1972"
TL;DR: In this article, the authors present a direct technique which can be applied in a large number of cases to circumvent the difficulties of programming complex algorithms for the computer, as well as excessive use of storage and computer time.
1,237 citations
TL;DR: In this article, a series of observations on experimentally produced vortex rings was described, and the flow field, ring velocity and growth rate were observed using dye and hydrogen-bubble techniques.
Abstract: A series of observations on experimentally produced vortex rings is described. The flow field, ring velocity and growth rate were observed using dye and hydrogen-bubble techniques. It was found that stable rings are formed and grow in such a way that most of their vorticity is distributed throughout a fluid volume which is larger than and moving with the visible dye core.As the vorticity diffuses out of this moving body of fluid into the outer irrotational fluid, it has two effects. It causes some of the fluid, with newly acquired vorticity, to be entrained into the interior of the bubble, while the rest is left behind and accounts for the appearance of ring vorticity in a wake. It was found that the velocity of translation U of these stable rings varies as t−1, at high Reynolds number, where t is the time measured from the start of the motion at a virtual origin at downstream infinity. A simple theoretical model is presented which explains all of these features of the observed stable flow. Rings of even higher Reynolds number become unstable and shed significantly more vorticity into the wake. Under some circumstances a new more stable vortex emerges from this shedding process and continues with less vorticity than before. Eventually, the ring motion ceases as all of its vorticity is deposited into the wake and is spread by viscous diffusion. Observations of the interaction between two nearly identical rings travelling a common path showed that, contrary to popular belief, rings do not pass back and forth through one another, but that the rearward one becomes entrained into the forward one. Only when the rearward ring has a much higher velocity than its partner can it emerge from the joining process and leave a slower-moving ring behind.
418 citations
TL;DR: In this article, the results of an exploratory study of shopper motivation suggest that some shopping trips are motivated by considerations that are unrelated to an actual purchase, and that people shop simply to make purchases.
Abstract: Do people shop simply to make purchases? Are some shopping trips motivated by considerations that are unrelated to an actual purchase? The results of an exploratory study of shopper motivation sugg...
386 citations
TL;DR: It is concluded that ovarian function is not depressed to post-menopausal levels in women receiving oral steroidal contraceptive agents.
312 citations
01 Jan 1972
TL;DR: In this paper, the problem of numbering a graph is to assign integers to the nodes so as to achieve a given goal, i.e., to assign integer values to each node in a graph so that the number of nodes in the graph can be expressed as a function of the relationship between the nodes and the target nodes.
Abstract: Publisher Summary This chapter explains the way of numbering a graph. The problem of numbering a graph is to assign integers to the nodes so as to achieve G(Г). The principal questions which arise in the theory of numbering the nodes of graphs revolve around the relationship between G(Г) and e, for example, identifying classes of graphs for which G(Г)= e and other classes for which G(Г)
297 citations
TL;DR: Two new programs, a telephone-answering service and the implementation of a policy to screen all candidates for admission by either a nurse clinical practitioner or a resident of the diabetes service, have served to reduce the annual admission rate of clinic patients to approximately one in five.
Abstract: Before 1969 the diabetes section at the Los Angeles County University of Southern California Medical Center, serving some 6000 medically indigent patients, averaged one hospital admission ...
283 citations
TL;DR: RD-114 virus, released from human rhabdomyosarcoma cells, has all the characteristics of a mammalian C-type virus and is the most likely candidate for a human C-types yet described.
Abstract: RD-114 virus, released from human rhabdomyosarcoma cells, has all the characteristics of a mammalian C-type virus. Immunological tests indicate that it differs from all known C-type viruses and is the most likely candidate for a human C-type virus yet described.
277 citations
270 citations
TL;DR: Excessive plasma-catecholamines in some patients may reflect increased sympathetic nerve tone and be a pathogenic factor in their hypertension.
254 citations
TL;DR: Opinion leadership has been studied intensively but rather narrowly in most studies to date, but an attempt is made to broaden the scope of coverage in order to learn about many dimensions or aspects of this phenomenon as it applies to a single population at a particular point in time.
Abstract: Opinion leadership has been studied intensively but rather narrowly in most studies to date. An attempt is made here to broaden the scope of coverage in order to learn about many dimensions or aspe...
248 citations
TL;DR: In this article, the threshold energies for energy and momentum-conserving impact ionization of electron-hole pairs in actual semiconductors are determined by differential analysis of the energy-wave-vector relations of the participating charge carriers and phonons.
Abstract: Threshold energies for energy- and momentum-conserving impact ionization of electron-hole pairs in actual semiconductors are determined by differential analysis of the energy-wave-vector relations of the participating charge carriers and phonons. A necessary condition for the initiating carrier to have minimum energy consistent with pair production is that the resultant carriers and all phonons involved have identical real-space velocities. This criterion allows calculations of ionization threshold energies for any semiconductor for which the one-electron-energy-wave-vector relationship is known. A step-by-step graphical procedure is presented for the calculation of threshold energies when the final particles are traveling along a principal axis of a semiconductor. Threshold energies resulting from the application of this procedure are presented for Si, Ge, GaAs, GaP, and InSb. Each of these materials exhibits numerous threshold energies for phononless ionization initiated by either type of carrier. The lowest thresholds for electron-initiated ionization without phonon assistance are 1.1, 0.8, 1.7, 2.6, and 0.2 eV relative to the conduction-band minima in Si, Ge, GaAs, GaP, and InSb, respectively. For ionization initiated by holes, the corresponding results are 1.8, 0.9, 1.4, 2.3, and 0.2 eV relative to the valence-band maximum.
01 Jul 1972
TL;DR: A dynamic model for pictorial data that can be represented by a random field of an exponential autocorrelation function is developed and is used to realize a two-dimensional recursive filter that gives a Bayesian-estimate of the pictorialData from a noisy observation of the data.
Abstract: A dynamic model for pictorial data that can be represented by a random field of an exponential autocorrelation function is developed. A partial difference equation describes the dynamic model and is used to realize a two-dimensional recursive filter that gives a Bayesian-estimate of the pictorial data from a noisy observation of the data. It is assumed that the noise is additive, white, and uncorrelated with the signal. Practical application of the estimation technique is illustrated by applying the results to enhance several pictures. A comparison of this technique and its one-dimensional counterpart (Kalman filter) is made, and generalization of the estimation technique to other autoregressive sources is considered.
TL;DR: Interference with the Lowry protein determination by sulfhydryl compounds cysteine, DTT, 2-mercaptoethanol, and reduced glutathione has been largely removed by adding H 2 O 2 to the alkaline copper solution containing the protein followed by heating for 10 min at 50° before adding phenol reagent.
01 Jan 1972
TL;DR: The need for a uniform method for measuring water quality - a “yardstick” with units that are simple, stable, consistent, and reproducible — and an unambiguous method for communicating this information to everyone concerned is at issue.
Abstract: Use of this somewhat bombastic title stems from our desire to draw critical attention to a process of decision making that in practice has been more of an art than a science. At issue is the long standing need for a uniform method for measuring water quality - a “yardstick” with units that are simple, stable, consistent, and reproducible — and an unambiguous method for communicating this information to everyone concerned.
TL;DR: The classical signal processing technique known as Wiener filtering has been extended to the processing of one-and two-dimensional discrete data by digital operations with emphasis on reduction of the computational requirements.
Abstract: The classical signal processing technique known as Wiener filtering has been extended to the processing of one-and two-dimensional discrete data by digital operations with emphasis on reduction of the computational requirements. In the generalized Wiener filtering process a unitary transformation, such as the discrete Fourier, Hadamard, or Karhunen-Loeve transform is performed on the data that is assumed to be composed of additive signal and noise components. The transformed data is then modified by a filter function, and the inverse transformation is performed to obtain the discrete system output. The filter function is chosen to provide the best mean square estimate of the signal portion of the input data.
TL;DR: Quantitative appraisal of renal function has been difficult when reliable urine collections from patients cannot be obtained for measurement of endogenous creatinine clearance by standard methods, so a computer program has been written for a hospital-based time-shared terminal to estimate CCr.
Abstract: Quantitative appraisal of renal function has been difficult when reliable urine collections from patients cannot be obtained for measurement of endogenous creatinine clearance (CCr) by standard methods. Previous estimates of CCr from data of stable serum creatinine have been reasonably accurate for clinical purposes. A reappraisal of this data, coupled with a dynamic model of creatinine kinetics in patients, has led to a method to estimate CCr even when serum creatinine levels and renal function are rapidly changing. A computer program has been written for a hospital-based time-shared terminal to estimate CCr in this manner.
TL;DR: The weight distribution of all 2^26 cosets of the (32,6) first-order Reed-Muller code is presented, and this equivalent problem: how well are the 2^32 Boolean functions of five variables approximated by the2^5 linear functions and their complements?
Abstract: In this paper we present the weight distribution of all 2^26 cosets of the (32,6) first-order Reed-Muller code. The code is invariant under the complete affine group, of order 32 \times 31 \times 30 \times 28 \times 24 \times 16. In the Appendix we show (by hand computations) that this group partitions the 2^26 cosets into only 48 equivalence classes, and we obtain the number of cosets in each class. A simple computer program then enumerated the weights of the 32 vectors ih each of the 48 cosets. These coset enumerations also answer this equivalent problem: how well are the 2^32 Boolean functions of five variables approximated by the 2^5 linear functions and their complements?
TL;DR: In this article, a new approach to the exact model matching problem is given based on an algorithm for characterizing the input-output structural properties of a linear system, which is solved without recourse to initial coordinate transformations.
Abstract: A new approach to the exact model matching problem is given based on an algorithm for characterizing the input-output structural properties of a linear system. In contrast to previous methods, the state feedback matching problem is solved without recourse to initial coordinate transformations. Moreover, the algorithm given here extends directly to the dynamic model matching problem and yields a set of necessary and sufficient conditions for one system to be transfer function equivalent via dynamic state feedback to a specified model system.
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TL;DR: In this article, the impact of a firm's history has on the future of the firm is examined and five dimensions are identified as key to the development of this model, i.e., the age of the organization, the size of an organization, stages of evolution and stages of revolution.
Abstract: Examines the impact that a firm's history has on the future of the firm. Firms pass through a series of developmental phases as they grow. Each of these phases begins with a period of calm ("evolution") and ends with a management crisis ("revolution"). By considering the history of the firm, i.e. the previous phases, the management of a growing firm can anticipate the next crisis and better prepare to deal with it. Five dimensions are identified as key to the development of this model. They are the age of the organization, the size of the organization, stages of evolution, stages of revolution, and growth rate of the industry. Based on these dimensions, the five phases of development for growing firms are identified. Each of these five phases starts with growth. The management styles which highlight these stages are creativity, direction, delegation, coordination, and collaboration, respectively. The crises that end each phase are leadership, autonomy, control, and red tape, respectively. Based on these phases, several recommendations are made for managers including understanding where the firm is in the developmental sequence and recognizing the limited range of solutions. (SRD)
TL;DR: Although prolonged follow-up is not yet available in the eight cases which are the basis of this study, the cells are interpreted as part of the basic proliferative process of infectious mononucleosis, rather than an indication of incipient Hodgkin's disease.
Abstract: The morphologic features of infectious mononucleosis are distinctive and in lymphoid tissue include a predominance of cytoplasmic or activated lymphocytes (Downey cells) and immunoblasts. The histologic process is unlike that of Hodgkin’s disease, but is associated with binucleated and multinucleated cells, some of which are indistinguishable morphologically from diagnostic Reed-Sternberg cells. The lack of specificity of the Reed-Sternberg cell, in the absence of the other histologic features of Hodgkin’s disease, is emphasized. Although prolonged follow-up is not yet available in the eight cases which are the basis of this study, the cells are interpreted as part of the basic proliferative process of infectious mononucleosis, rather than an indication of incipient Hodgkin’s disease.
TL;DR: In this paper, a simple expression for the ionization coefficient of charged carriers in a semiconductor as a function of electric field and lattice temperature has been developed by simultaneously fitting three physical asymptotic cases to Baraff's result.
Abstract: A simple expression for the ionization coefficient of charged carriers in a semiconductor as a function of electric field and lattice temperature has been developed by simultaneously fitting three physical asymptotic cases to Baraff's result. These cases are for low field (Shockley), high field (Wolff), and limitations imposed by energy conservation at high electric field or when the energy loss by phonon scattering is negligible. Given the threshold energy for ionization and the optical-phonon energy, our expression requires a single additional parameter to predict experimental results. Although the final expression is thus essentially a one-point fitting, it reproduces experimental data over as much as four decades of ionization coefficient with better accuracy than frequently used empirical two-parameter expressions. Excellent fits with much of the existing electric field dependence of the ionization coefficients for electrons and holes in Ge, Si, GaAs, and GaP were obtained. The temperature dependence was examined in the cases of GaAs and Si and excellent agreement was obtained in the case of GaAs. Some data on Si were found to be in considerable error in the sense that the data do not appear to be consistent with energy conservation.
TL;DR: A comprehensive theoretical treatment of the factors governing the solubility of uric acid and monosodium urate is given, using both existing data and new experimental data.
Abstract: A comprehensive theoretical treatment of the factors governing the solubility of uric acid and monosodium urate is given. The various constants appearing in the treatment are evaluated as functions of temperature and ionic strength using both existing data and new experimental data. The solubility of uric acid increases with increasing pH, while the solubility of monosodium urate has a minimum near pH 7·7 at 37°C. The solubility product of monosodium urate increases with increasing ionic strength.
TL;DR: No significant change was found in urine stored at −20° up to 30 days in a semi-automatic titrimetric method for rapid determination of urinary net acid concentration.
TL;DR: A smectite rich in ferrous iron and low in aluminum occurs abundantly in the Red Sea Geothermal Deposits, and appear to be forming at present as discussed by the authors, and chemical analyses and M/Assbauer spectra indicate the mineral is intermediate in composition between nontronite and the as yet undescribed three-dimensional ferrous-iron end member.
Abstract: A smectite rich in ferrous iron and low in aluminum occurs abundantly in the Red Sea Geothermal Deposits, and appear to be forming at present. Chemical analyses and M/Assbauer spectra indicate the mineral is intermediate in composition between nontronite and the as yet undescribed trioctahedral ferrous iron end member.