Showing papers by "Tel Aviv University published in 1987"
TL;DR: An hierarchy of uniformly high-order accurate schemes is presented which generalizes Godunov's scheme and its second- order accurate MUSCL extension to an arbitrary order of accuracy.
2,891 citations
TL;DR: In this paper, a reconsideration and reformulation of the Mori-Tanaka's theory in its application to the computation of the effective properties of composites is presented, which is a straightforward exposition and interpretation of the method which are different than those existing in previous formulations.
2,419 citations
TL;DR: In this article, three hypotheses about the behavior of intraindustry trade in cross-country comparisons and time series data are discussed, and the authors conclude that changes over time in relative country size can explain the rising trade-income ratio.
Abstract: Three hypotheses that emerge from a theoretical model are discussed. Two of them concern the behavior of the share of intraindustry trade while the third concerns the volume of trade. One is that in cross-country comparisons the larger the similarity in factor composition, the larger the share of intraindustry trade. The second is that in time series data the more similar the factor composition of a group of countries becomes over time, the larger the share of intraindustry trade within the group. The third is that changes over time in relative country size can explain the rising trade-income ratio. All three hypotheses are consistent with the data. J. Japan. Int. Econ., March 1987, 1(1), pp. 62–81. Department of Economics, Tel Aviv University, Ramat-Aviv, Tel Aviv 69978, Israel.
1,096 citations
TL;DR: A uniformly second-order approximation of hyperbolic conservation laws is constructed, which is nonoscillatory in the sense that the number of extrema of the discrete solution is not increasing in time.
Abstract: We begin the construction and the analysis of nonoscillatory shock capturing methods for the approximation of hyperbolic conservation laws. These schemes share many desirable properties with total variation diminishing schemes, but TVD schemes have at most first-order accuracy, in the sense of truncation error, at extrema of the solution. In this paper we construct a uniformly second-order approximation, which is nonoscillatory in the sense that the number of extrema of the discrete solution is not increasing in time. This is achieved via a nonoscillatory piecewise-linear reconstruction of the solution from its cell averages, time evolution through an approximate solution of the resulting initial value problem and an average of this approximate solution over each cell.
1,031 citations
TL;DR: It is sown that the resultant incompressible equations form a symmetric hyperbolic system and so are well posed, and several generalizations to the compressible equations are presented which extend previous results.
866 citations
TL;DR: In this article, the Ellsberg paradox was used to reject one of Savage's main axioms -the Sure Thing Principle -and develop a more general theory, in which the probability measure need not be additive.
814 citations
TL;DR: A 4-point interpolatory subdivision scheme with a tension parameter is analysed and it is shown that for a certain range of the tension parameter the resulting curve is C^1.
651 citations
TL;DR: In this article, models for predicting flow-pattern transitions in steady gas-liquid flow in pipes are summarized and presented, incorporating the effect of fluid properties, pipe size and the angle of inclination in a unified way.
550 citations
TL;DR: Given a triangulation of a simple polygonP, linear-time algorithms for solving a collection of problems concerning shortest paths and visibility withinP are presented.
Abstract: Given a triangulation of a simple polygonP, we present linear-time algorithms for solving a collection of problems concerning shortest paths and visibility withinP. These problems include calculation of the collection of all shortest paths insideP from a given source vertexS to all the other vertices ofP, calculation of the subpolygon ofP consisting of points that are visible from a given segment withinP, preprocessingP for fast "ray shooting" queries, and several related problems.
544 citations
TL;DR: The short coherence length of high-${\mathrm{T}$ oxides is shown to induce considerable weakening of the pair potential at surfaces and interfaces, and it is argued that this effect is responsible for the existence of internal Josephson junctions at twin boundaries.
Abstract: The short coherence length of high-${\mathrm{T}}_{\mathrm{c}}$ oxides is shown to induce considerable weakening of the pair potential at surfaces and interfaces. It is argued that this effect is responsible for the existence of internal Josephson junctions at twin boundaries, which are at the origin of the superconductive glassy state, as well as for gapless tunneling characteristics.
521 citations
TL;DR: This paper investigated the influence of positive affect, induced by a small bag of candy, on risk preference and on thoughts about losing and found that persons in the positive affect condition tended to be more risk prone (to set a lower probability level) than control subjects.
TL;DR: This protocol improves the known lower bound on the number of correct processes necessary for consensus, and uses a general technique in which the behavior of the Byzantine processes is restricted by the use of a broadcast protocol that filters some of the messages.
Abstract: A consensus protocol enables a system of n asynchronous processes, some of them faulty, to reach agreement. Both the processes and the message system are capable of cooperating to prevent the correct processes from reaching decision. A protocol is t -resilient if in the presence of up to t faulty processes it reaches agreement with probability 1. Byzantine processes are faulty processes that can deviate arbitrarily from the protocol; Fail-Stop processes can just stop participating in it. In a recent paper, t -resilient randomized consensus protocols were presented for t n 5 . We improve this to t n 3 , thus matching the known lower bound on the number of correct processes necessary for consensus. The protocol uses a general technique in which the behavior of the Byzantine processes is restricted by the use of a broadcast protocol that filters some of the messages. The apparent behavior of the Byzantine processes, filtered by the broadcast protocol, is similar to that of Fail-Stop processes. Plugging the broadcast protocol as a communicating primitive into an agreement protocol for Fail-Stop processes gives the result. This technique, of using broadcast protocols to reduce the power of the faulty processes and then using them as communication primitives in algorithms designed for weaker failure models, was used succesfully in other contexts.
TL;DR: It is shown that conservative schemes are entropy stable, if and (for three-point schemes) only they contain more viscosity than that present in the above-mentioned entropy-conservative ones.
Abstract: Discrete approximations to hyperbolic systems of conservation laws are studied. The amount of numerical viscosity present in such schemes, is quantified and related to their entropy stability by means of comparison. To this end, conservative schemes which are also entropy conservative are constructed. These entropy conservative schemes enjoy second-order accuracy; moreover, they admit a particular interpretation within the finite-element frameworks, and hence can be formulated on various mesh configurations. It is then shown that conservative schemes are entropy stable if and only if they contain more viscosity than the mentioned above entropy conservative ones.
TL;DR: The arguments of Razborov are modified to obtain exponential lower bounds for circuits, and the best lower bound for an NP function ofn variables is exp (Ω(n1/4 · (logn)1/2)), improving a recent result of exp ( Ω( n1/8-ε)) due to Andreev.
Abstract: Recently, Razborov obtained superpolynomial lower bounds for monotone circuits that cliques in graphs. In particular, Razborov showed that detecting cliques of sizes in a graphm vertices requires monotone circuits of size Ω(m
s
/(logm)2s
) for fixeds, and sizem
Ω(logm) form/4]. In this paper we modify the arguments of Razborov to obtain exponential lower bounds for circuits. In particular, detecting cliques of size (1/4) (m/logm)2/3 requires monotone circuits exp (Ω((m/logm)1/3)). For fixeds, any monotone circuit that detects cliques of sizes requiresm)
s
) AND gates. We show that even a very rough approximation of the maximum clique of a graph requires superpolynomial size monotone circuits, and give lower bounds for some Boolean functions. Our best lower bound for an NP function ofn variables is exp (Ω(n
1/4 · (logn)1/2)), improving a recent result of exp (Ω(n
1/8-e)) due to Andreev.
TL;DR: In this paper, the results of a meta-analysis on findings of 41 different studies yielded 77 correlation coefficients between measures of personality-environment congruence and well-being, with negligible residual variance.
TL;DR: Mindfulness is a mid-level construct which reflects a voluntary state of mind, and connects among motivation, cognition, and learning as discussed by the authors, and plays various important roles in different kinds of learning and transfer situations.
TL;DR: In this article, the stochastic collection equation (SCE) is converted to a set of moment equations in categories using a new analytical form of Bleck&'s approach, which is written in a form amenable to solution and to a category-by-category analysis of drop formation and removal.
Abstract: A new, accurate, efficient method for solving the stochastic collection equation (SCE) is proposed. The SCE is converted to a set of moment equations in categories using a new analytical form of Bleck&'s approach. The equations are written in a form amenable to solution and to a category-by-category analysis of drop formation and removal. This method is unique in that closure of the equations is achieved using an expression relating high-order moments to any two lower order moments, thereby restricting the need for approximation of the category distribution function only to integrals over incomplete categories. Moments in categories are then expressed in terms of complete moments with the aid of linear or cubic polynomials. The method is checked for the case of the constant kernel and a linear polynomial kernel. Results show that excellent approximation to the analytical solutions for these kernels are obtained. This is achieved without the use of weighting functions and with modest computing tim...
TL;DR: In this article, the authors derived a set of differential equations for the eigenvalues and eigenvectors of the stability matrix of a dynamical system, as well as for the Lyapunov exponents and the corresponding eigenvector.
TL;DR: In this article, the authors give the mathematical foundations for the BRS quantization procedure and discuss the classical finite dimensional BRS procedure and relate it to Marsden-Weinstein reduction.
TL;DR: In an extensive ethnobotanical survey of the medicinal plants of Israel, 16 species were found to be used for hypoglycaemic treatments and eight are first recorded here as used for this purpose.
TL;DR: The quantity of plasma cell burden in the biopsy proved to be a useful criterion for histologic staging of MM, supplementing any clinical staging system in use, and provided information required for decisions on treatment modalities.
Abstract: Bone marrow biopsies of 674 patients with multiple myeloma (MM) were processed for diagnostic evaluation. Histologic variables were correlated with the clinical features to determine factors of value in predicting prognosis. Four of these were used to classify MM into six histologic types: Marschalko type; small cell type; cleaved type; polymorphous type; asynchronous type; and blastic type. These six types were subsequently combined into three prognostic grades: low, intermediate, and high, analogous to the malignant lymphomas. The quantity of plasma cell burden in the biopsy proved to be a useful criterion for histologic staging of MM, supplementing any clinical staging system in use. Both these parameters, grade and stage, provide information required for decisions on treatment modalities, while the effects of therapy can be monitored by sequential biopsies.
TL;DR: In this article, the general equilibrium effects of tariffs, export subsidies, output subsidies, and RD subsidies in a monopolistically competitive sector that produces differentiated products are studied. But the results depend on identifiable details of the production structure, the sectoral interlinkages through factor markets and preferences.
TL;DR: Host tRNAs cleaved near the anticodon occur specifically in T4‐infected Escherichia coli prr strains which restrict polynucleotide kinase (pnk) or RNA ligase (rli) phage mutants, and the nuclease, kinase and ligase may benefit T4 directly, by adapting levels or decoding specificities of host t RNAs to T4 codon usage.
Abstract: Host tRNAs cleaved near the anticodon occur specifically in T4-infected Escherichia coli prr strains which restrict polynucleotide kinase (pnk) or RNA ligase (rli) phage mutants. The cleavage products are transient with wt but accumulate in pnk- or rli- infections, implicating the affected enzymes in repair of the damaged tRNAs. Their roles in the pathway were elucidated by comparing the mutant infection intermediates with intact tRNA counterparts before or late in wt infection. Thus, the T4-induced anticodon nuclease cleaves lysine tRNA 5' to the wobble position, yielding 2':3'-P greater than and 5'-OH termini. Polynucleotide kinase converts them into a 3'-OH and 5' P pair joined in turn by RNA ligase. Presumably, lysine tRNA depletion, in the absence of polynucleotide kinase and RNA ligase mediated repair, underlies prr restriction. However, the nuclease, kinase and ligase may benefit T4 directly, by adapting levels or decoding specificities of host tRNAs to T4 codon usage.
TL;DR: In this paper, the available seismic refraction and gravity data using modern interpretation techniques and incorporated new information derived from magnetic, gravity, seismicity and seismic fronherency data.
TL;DR: In this paper, the authors reported that ther-moluminescence dates from 38 specimens of burnt flint recovered from 4 m of Kebara deposits range from about 60,000 to 48,000 years before present (BP), indicating that Neanderthals were present in the Levant in the latter part of the middle Palaeolithic.
Abstract: The origins of modern man are a subject of controversy among palaeoanthropologists concerned with human evolution1–3 Particularly heavily debated is the dating of hominid remains uncovered in southwestern Asia, because middle palaeolithic sites have provided skeletal remains classified as representing Neanderthals (Homo sapiens neanderthalensis at Tabun, Amud, Kebara and Shanidar caves) and proto-Cro-Magnons (Homo sapiens sapiens at Skhul and Qafzeh caves) This situation differs considerably from that of Western Europe, where only Neanderthal remains are known from archaeological deposits of this period, or that of the African continent, where no Neanderthal remains have so far been found Two opposing hypotheses have been offered to explain the relations between Neanderthals and the earliest modern Homo sapiens: first that modern Homo sapiens appeared very early in the Mediterranean Levant and coexisted with a population of Neanderthals who had arrived at a later date; and second that modern humans developed from the local Neanderthal population in southwestern Asia Recent excavations at the Kebara cave yielded Neanderthal burial in a well-documented stratigraphic and cultural Mousterian sequence4,5 We now report that ther-moluminescence dates from 38 specimens of burnt flint recovered from 4 m of Kebara deposits range from about 60,000 to 48,000 years before present (BP), indicating that Neanderthals were present in the Levant in the latter part of the middle Palaeolithic
TL;DR: The authors examined the effects of motivational variables on the epistemic (or knowledge acquisition) process of subjective confidence and hypothesis generation and found that both initial and final confidence and informationally induced confidence shifts were of higher magnitude when subjects' need for structure was high rather than low, and when their fear of invalidity was low rather than high.
TL;DR: In this article, the effect of damage due to imperfect bonding between the constituents of composite materials is considered and the interface decohesion is described by two parameters which completely determine the degree of adhesion at the interfaces in the normal and tangential directions.
TL;DR: A marked reduction in the power of heart rate fluctuations, at all frequencies, was found in the diabetic patients as compared to controls, which indicates a depression of both parasympathetic and sympathetic activity.
Abstract: Early detection and a quantitative evaluation of the degree of diabetic autonomic neuropathy were performed in 23 diabetic patients and 22 controls by computerized spectral analysis of beat-to-beat R-R interval variations on a continuous electrocardiogram. Simultaneous recording of cardiac and respiratory activity, R-wave detection by a fast peak detection algorithm and spectrum computation by Fast Fourier transform enabled the study of the power spectrum of heart rate fluctuations. The power of fluctuations at different frequencies is the result of sympathetic and vagal input into the sinoatrial node: this input is derived from vasomotor, baroreceptor and respiratory control loops. A marked reduction in the power of heart rate (HR) fluctuations, at all frequencies, was found in the diabetic patients as compared to controls. This indicates a depression of both parasympathetic and sympathetic activity. The difference was especially pronounced in subjects below age 65. The lowest activity was found in diabetics with concomitant peripheral neuropathy. The method described here is simple, objective, quantitative and very sensitive. It may facilitate the screening of diabetic patients for autonomic neuropathy and enable a convenient quantitative follow-up.
TL;DR: The findings indicate a high rate of stability in self-reporting of substance use, both cross-sectionally and longitudinally, in agreement with other studies of self-reported drug use and suggest that questionnaire may provide highly reliable data for research.
Abstract: Summary
The paper presents an evaluation of the stability and consistency of self-reported adolescent drug use. The data were collected from 1900 high-school students. Analyses included estimates of alternate forms reliability, non-response rates, logical consistency in the responses, test-retest reliability as well as estimates of exaggerated reports. The findings indicate a high rate of stability in self-reporting of substance use, both cross-sectionally and longitudinally. These results are in agreement with other studies of self-reported drug use and suggest that questionnaire may provide highly reliable data for research.
TL;DR: Lectin-histochemical studies were performed on formalin-fixed, paraffin-embedded tissues from ten mammalian species to demonstrate the pattern of carbohydrate residues in vascular endothelium to highlight individual differences in staining.
Abstract: Lectin-histochemical studies were performed on formalin-fixed, paraffin-embedded tissues from ten mammalian species to demonstrate the pattern of carbohydrate residues in vascular endothelium. Ten different biotinylated lectins were used as probes and avidin-biotin-peroxidase complex (ABC) was used as visualant. Ricinus communis agglutinin-I (RCA-I) and wheat germ agglutinin (WGA) stained vascular endothelium in all species. Peanut agglutinin (PNA) stained vascular endothelium in all species only after preincubation with neuraminidase. Bandeirea simplicifolia agglutinin-I (BS-I) stained vascular endothelium in all species but human, while Ulex europeus agglutinin-I (UEA-I) stained only human endothelium. Individual differences in staining of human vascular endothelium were noted with BS-I and succinylated-WGA (SWGA). Similarly, individual differences in staining of animal vascular endothelium were noted with soybean agglutinin (SBA) after preincubation with neuraminidase. Finally, Concanavalia ensiformis agglutinin (Con A), Dolichos biflorus agglutinin (DBA) and Lens culinaris agglutinin (LCA) did not stain vascular endothelium in any of the species studied.