Showing papers by "Tel Aviv University published in 1981"
01 Jun 1981
TL;DR: In this paper, a new combination of a finite volume discretization in conjunction with carefully designed dissipative terms of third order, and a Runge Kutta time stepping scheme, is shown to yield an effective method for solving the Euler equations in arbitrary geometric domains.
Abstract: A new combination of a finite volume discretization in conjunction with carefully designed dissipative terms of third order, and a Runge Kutta time stepping scheme, is shown to yield an effective method for solving the Euler equations in arbitrary geometric domains. The method has been used to determine the steady transonic flow past an airfoil using an O mesh. Convergence to a steady state is accelerated by the use of a variable time step determined by the local Courant member, and the introduction of a forcing term proportional to the difference between the local total enthalpy and its free stream value.
4,220 citations
23 Jun 1981
TL;DR: In this article, a new combination of a finite volume discretization in conjunction with carefully designed dissipative terms of third order, and a Runge Kutta time stepping scheme, is shown to yield an effective method for solving the Euler equations in arbitrary geometric domains.
Abstract: A new combination of a finite volume discretization in conjunction with carefully designed dissipative terms of third order, and a Runge Kutta time stepping scheme, is shown to yield an effective method for solving the Euler equations in arbitrary geometric domains. The method has been used to determine the steady transonic flow past an airfoil using an O mesh. Convergence to a steady state is accelerated by the use of a variable time step determined by the local Courant member, and the introduction of a forcing term proportional to the difference between the local total enthalpy and its free stream value.
1,363 citations
TL;DR: In this paper, the authors present a generalization of the Heckscher-Ohlin theory by admitting the existence of sectors in which there is monopolistic competition and show that the intersectoral pattern of trade can be predicted from factor endowments but not from pre-trade commodity prices or factor rewards.
1,100 citations
TL;DR: It is demonstrated that specification of the Temporal character of the program's behavior is absolutely essential for the unambiguous understanding of the meaning of programming constructs.
740 citations
TL;DR: In this article, the maximal Lie group or abstract monoid of symmetries of an ordinary non-singular differential equation (or system of equations) allows us to obtain solutions of them.
Abstract: The knowledge of the maximal Lie group or abstract monoid of symmetries of an ordinary non-singular differential equation (or system of equations) allows us to obtain solutions of them. Traditional similarity analysis of point transformations is extended to non-point transformations (inclusion of derivatives), giving analytic expressions for solutions, where previously only numerical methods were used. Examples are given, and the didactic aspect is emphasised.
625 citations
TL;DR: No evidence was found to suggest a role for a cyclic nucleotide messenger and the common mechanism by which such a variety of stimuli provoke an OB in MPs was not elucidated.
477 citations
TL;DR: A direct way to construct a family of l inear concentrators using Pinsker’s linear concentrators and disproved a conjecture that superconcentrators require more than a linear number of edges.
451 citations
TL;DR: The authors found that it is possible to identify culturally and stylistically inappropriate L2 utterances in apology situations and that the results so far provide at best a crude measure of sociocultural competence.
Abstract: For a number of years, there has been interest in measuring sociocultural competence (Ervin-Tripp 1972, Hymes 1974, Canale and Swain 1980). This study focuses on one important aspect of such competence: the ability to use the appropriate sociocultural rules of speaking, by reacting in a culturally acceptable way in context and by choosing stylistically appropriate forms for that context. We chose to look at productive performance in sociocultural aspects of speaking, focusing on the speech act of “apology.” The research question that prompted this study was, “Can a rating scale be developed for assessing sociocultural competence?”
The subjects were 32 native Hebrew speakers, 20 of whom served as informants for apologies in English LZ and 12 as informants in Hebrew LI, and 12 Americans who served as informants in English LI. These subjects were asked to role-play their responses in eight situations in which an apology was expected.
The findings show that it is possible to identify culturally and stylistically inappropriate L2 utterances in apology situations. The authors feel, however, that the results so far provide at best a crude measure of sociocultural competence and that further work with this speech act and with others is called for.
330 citations
TL;DR: Investigation of the sequence specificities of the 2-5A-dependent ribonucleases in extracts of rabbit reticulocytes, mouse ascites tumour cells and human lymphoblastoid cells in conditions of partial digestion using terminally labelled RNA substrates found the enzymes cleaved on the 3′-side of UN sequences to yield UpNp terminated products.
Abstract: The oligonucleotides pppA2'p5'A2'p5'A and related oligomers (2-5A) are synthesized by an enzyme that is widely distributed in a variety of cells, the activity of which varies with interferon treatment, growth and hormone status. Because significant amounts of 2-5A have recently been detected in interferon-treated cells, it has been suggested that the oligonucleotides may be involved in interferon action and in the control of cell metabolism. In both intact cells and cell-free systems 2-5A has been shown to activate a ribonuclease. We report here investigations of the sequence specificities of the 2-5A-dependent ribonucleases in extracts of rabbit reticulocytes, mouse ascites tumour cells and human lymphoblastoid cells in conditions of partial digestion using terminally labelled RNA substrates. The enzymes cleaved on the 3'-side of UN sequences to yield UpNp terminated products. Cleavage was observed predominantly at UA and UU sequences.
309 citations
TL;DR: In this article, the authors analyzed the professional commitment of Canadian Chartered Accountants who are partners, managers (supervisors) and other staff CAs in public practice in relation to organizational commitment, professional-organizational conflict, satisfaction with income and organizational level.
Abstract: This study analyzes the professional commitment of Canadian Chartered Accountants who are partners, managers (supervisors) and other staff CAs in public practice. This commitment is examined in relation to organizational commitment, professional-organizational conflict, satisfaction with income and organizational level. The commitment to organization is shown to be the most powerful predictor of CAs' professional commitment in all organizational levels. At the same time, professional-organizational conflict has a negative impact on professional commitment, and satisfaction with income has a positive influence on such a commitment.
282 citations
TL;DR: In this paper, a family of scale-invariant fractal lattices is described, on which statistical mechanics and conductivity problems are exactly solvable for every $d. Critical exponents calculated for this model agree with those of "real" systems at low dimensionalities.
Abstract: A nontrivial family of $d$-dimensional scale-invariant fractal lattices is described, on which statistical mechanics and conductivity problems are exactly solvable for every $d$. These fractals are finitely ramified but not quasi one dimensional, and hence can be used to model the important geometrical features of the percolating cluster's backbone. Critical exponents calculated for this model agree with those of "real" systems at low dimensionalities.
TL;DR: In this paper, the authors studied the modification of optical properties of two metal spheres brought about by their electromagnetic interactions, and computed the excitation spectrum of the two sphere system and studied the shape and the magnitude of the local fields.
TL;DR: In this paper, three dimensional fatigue failure criteria for unidirectional fiber composites under states of cyclic stress are established in terms of quadratic stress polynomials which are expressed by the transversely isotropic invariants of the cyclic stresses.
Abstract: : Three dimensional fatigue failure criteria for unidirectional fiber composites under states of cyclic stress are established in terms of quadratic stress polynomials which are expressed in terms of the transversely isotropic invariants of the cyclic stress. Two distinct fatigue failure modes, fiber mode and matrix mode, are modelled separately. Material information needed for the failure criteria are the S-N curves for single stress components. A preliminary approach to incorporate scatter into the failure criteria is presented. (Author)
TL;DR: The theory of kin selection, as developed by Hamilton, stems from the fact that in a sexually reproducing population, the genotype of a progeny of an individual is not necessarily identical to the genotypes of either parent, so natural selection cannot operate through the preservation of the most tit type.
TL;DR: Results indicate that, particularly in older age-groups, measures designed to increase HDL cholesterol may prove as valuable in preventing CHD as those designed to reduce low density lipoprotein cholesterol.
TL;DR: In this article, the axial anomaly of three-point functions of colour singlet currents in quark confining theories implies the presence of zero-mass bound states in the physical spectrum.
26 Jan 1981
TL;DR: A temporal language and system are presented which are based on branching time structure and it is possible to express in this system all the properties that were previously expressible in linear time or branching time systems.
Abstract: A temporal language and system are presented which are based on branching time structure. By the introduction of symmetrically dual sets of temporal operators, it is possible to discuss properties which hold either along one path or along all paths. Consequently it is possible to express in this system all the properties that were previously expressible in linear time or branching time systems. We present an exponential decision procedure for satisfiability in the language based on tableaux methods, and a complete deduction system. As associated temporal semantics is illustrated for both structured and graph representation of programs.
TL;DR: It is concluded that intraperitoneal placement of Marlex mesh is not recommended in a patient who had a gastrectomy for recurrent duodenal ulcer.
Abstract: Marlex® mesh is an excellent prosthetic material for closure of major abdominal defects. Most of its complications are seroma and infections. We have used Marlex mesh intraperitoneally for closure of burst abdomen in a patient who had a gastrectomy for recurrent duodenal ulcer. A year and a half later, this patient developed a fecal fistula to the skin due to incorporation of the Marlex mesh into the splenic flexure of the colon. The patient underwent a second operation during which the fistula was resected and the Marlex removed. We concluded that intraperitoneal placement of Marlex mesh is not recommended.
TL;DR: The method was applied to human red blood cell where the main thiols were found to be glutathione and ergothioneine, in accord with earlier reports.
TL;DR: This chapter deals with a theory to account for the latent inhibition (LI) phenomenon in particular, and other stimulus pre-exposure phenomena with special reference to such paradigms as habituation, learned helplessness, sensory preconditioning, blocking, and the feature positive effect.
Abstract: Publisher Summary This chapter deals with a theory to account for the latent inhibition (LI) phenomenon in particular, and other stimulus pre-exposure phenomena with special reference to such paradigms as habituation, learned helplessness, sensory preconditioning, blocking, and the feature positive effect. The theory is based on the application of conditioning principles during the stimulus pre-exposure phase of a transfer experiment conditioned attention theory. LI is a decrement in learning performance that results from repeated non-reinforced pre-exposure of the to-be-conditioned stimulus. Empirical support for these predictions is drawn from a series of experiments specifically designed to evaluate the theory and from experiments designed outside the theory's framework.
TL;DR: Scheduling procedure for the solution of the problem of given processing times of n jobs on a single machine with penalties for earliness and tardiness and penalties associated with assignment of due-dates is presented.
Abstract: Given processing times of n jobs on a single machine with penalties for earliness and tardiness and penalties associated with assignment of due-dates, the objective is to select optimal due-dates and optimal sequence. Scheduling procedure for the solution of this problem is presented along with proof of optimality and illustrative numerical examples.
TL;DR: It is concluded that pSB2 in Y. pseudotuberculosis and Y. enterocolitica carry genetic information essential for virulence common to the Yersinia species, probably related to VW antigen production.
Proceedings Article•
01 Jan 1981TL;DR: An algorithm is designed and analyzed which realizes both asymptotic bounds simultaneously and makes possible a completely general implementation as a Fortran subroutine or even as a six-head finite automaton.
Abstract: Any string-matching algorithm requires at least linear time and a constant number of local storage locations. We design and analyze an algorithm which realizes both asymptotic bounds simultaneously. This can be viewed as completely eliminating the need for the tabulated “failure function” in the linear-time algorithm of Knuth, Morris, and Pratt. It makes possible a completely general implementation as a Fortran subroutine or even as a six-head finite automaton.
TL;DR: In this paper, a new explicit, time splitting algorithm for finite difference modeling of the Navier-Stokes equations of fluid mechanics is presented. But it is not shown that the split operators achieve their maximum allowable time step, i.e., the corresponding Courant number.
TL;DR: It was shown in several ways that the variety of “freezer” individuals was not due to a need for multicell aggregation or any other cooperative process, and the time at which a given individual in a cell population expressed its latent freezing potential was shown to vary with time and cell physiological state.
Abstract: Freezing spectra of INA bacteria from different parts of the world were compared. A slight increase in efficiency of freezing nuclei produced by strains from warmer climates was observed. Whole cells of the most efficient strain produced nuclei active at temperatures ranging from −2 to −10°C, whereas fragments from these cells exhibited activity only at −8 to −10°C. In all cases, the frequency of active cells in a population proved low. Thus, activity at −8 to −10°C was evidenced by 1 cell in about 300, the corresponding ratio being 1 in 104 at −2 to −4°C. It was shown in several ways that the variety of “freezer” individuals was not due to a need for multicell aggregation or any other cooperative process. Also, the time at which a given individual in a cell population expressed its latent freezing potential was shown to vary with time and cell physiological state.
TL;DR: In this paper, two nonlinear transformations, the D-transformation to accelerate the convergence of infinite integrals and the d -transformation for infinite series, are presented, and the computational aspects of these transformations are described in detail.
TL;DR: Li et al. as discussed by the authors measured the true absorption cross section of pions in nuclei at 85, 125, 165, 205, 245, and 315 MeV for positive pions and at 125 and 165 MEV for negative pions.
Abstract: The cross section for true absorption of pions in nuclei was obtained from experiments at 85, 125, 165, 205, 245, and 315 MeV for positive pions and at 125 and 165 MeV for negative pions. The results are compared with theoretical calculations. The inclusive pion scattering angular distribution was also measured, and the results indicate that quasifree scattering plays an important role for backward scattering. The total pion-nucleus cross section is decomposed into its major channels: elastic scattering, inclusive inelastic scattering, true absorption, and single charge exchange, as a function of pion energy and charge. For light nuclei, the true absorption cross section has a strong energy dependence, reflecting the shape of the (3,3) resonance. The $A$ dependence of the true absorption cross section is much stronger than that of the inclusive inelastic scattering.NUCLEAR REACTIONS Li, C, Al, Fe, Nb, Bi (${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}},{\ensuremath{\pi}}^{\ensuremath{'}}$); measured $\ensuremath{\sigma}({\ensuremath{\theta}}_{{\ensuremath{\pi}}^{\ensuremath{'}}})$, ${E}_{{\ensuremath{\pi}}^{+}}=85, 125, 165, 205, 245, \mathrm{and} 315$ MeV, ${E}_{{\ensuremath{\pi}}^{\ensuremath{-}}}=125, 165$ MeV; deduced ${\ensuremath{\sigma}}_{\mathrm{inelastic}}$, ${\ensuremath{\sigma}}_{\mathrm{absorption}}$; decomposition of ${\ensuremath{\sigma}}_{\mathrm{tot}}$.
TL;DR: The results indicate that mating is a biological stimulus for the release of endogenous opoids, possibly to prevent intense sexual stimulation from becoming aversive, and increase its reward value.
TL;DR: Comparison shows that healthy subjects definitely possess a more efficient shock-absorbing capacity than do those subjects with joint disorders, and that degenerative changes in joints reduce their shock absorbing capacity, which leads to overloading of the next shock absorber in the locomotor system.
Abstract: A method to measure the capability of the human shock absorber system to attenuate input dynamic loading during the gait is presented. The experiments were carried out with two groups: healthy subjects and subjects with various pathological conditions. The results of the experiments show a considerable difference in the capability of each group's shock absorbers to attenuate force transmitted through the locomotor system. Comparison shows that healthy subjects definitely possess a more efficient shock-absorbing capacity than do those subjects with joint disorders. Presented results show that degenerative changes in joints reduce their shock absorbing capacity, which leads to overloading of the next shock absorber in the locomotor system. So, the development of osteoarthritis may be expected to result from overloading of a shock absorber's functional capacity.