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Showing papers by "Tel Aviv University published in 1995"


Journal ArticleDOI
TL;DR: Numerical evidence is presented that this model results in a kinetic phase transition from no transport to finite net transport through spontaneous symmetry breaking of the rotational symmetry.
Abstract: A simple model with a novel type of dynamics is introduced in order to investigate the emergence of self-ordered motion in systems of particles with biologically motivated interaction. In our model particles are driven with a constant absolute velocity and at each time step assume the average direction of motion of the particles in their neighborhood with some random perturbation $(\ensuremath{\eta})$ added. We present numerical evidence that this model results in a kinetic phase transition from no transport (zero average velocity, $|{\mathbf{v}}_{a}|\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0$) to finite net transport through spontaneous symmetry breaking of the rotational symmetry. The transition is continuous, since $|{\mathbf{v}}_{a}|$ is found to scale as $({\ensuremath{\eta}}_{c}\ensuremath{-}\ensuremath{\eta}{)}^{\ensuremath{\beta}}$ with $\ensuremath{\beta}\ensuremath{\simeq}0.45$.

6,514 citations


Journal ArticleDOI
TL;DR: In this paper, a model is presented based on recent theories of economic growth that treat commercially oriented innovation efforts as a major engine of technological progress, and the authors study the extent to which a country's total factor productivity depends not only on domestic R&D capital but also on foreign capital.

3,397 citations


Journal ArticleDOI
23 Jun 1995-Science
TL;DR: A gene, ATM, that is mutated in the autosomal recessive disorder ataxia telangiectasia was identified by positional cloning on chromosome 11q22-23 and encoded a putative protein that is similar to several yeast and mammalian phosphatidylinositol-3' kinases that are involved in mitogenic signal transduction, meiotic recombination, and cell cycle control.
Abstract: A gene, ATM, that is mutated in the autosomal recessive disorder ataxia telangiectasia (AT) was identified by positional cloning on chromosome 11q22-23. AT is characterized by cerebellar degeneration, immunodeficiency, chromosomal instability, cancer predisposition, radiation sensitivity, and cell cycle abnormalities. The disease is genetically heterogeneous, with four complementation groups that have been suspected to represent different genes. ATM, which has a transcript of 12 kilobases, was found to be mutated in AT patients from all complementation groups, indicating that it is probably the sole gene responsible for this disorder. A partial ATM complementary DNA clone of 5.9 kilobases encoded a putative protein that is similar to several yeast and mammalian phosphatidylinositol-3' kinases that are involved in mitogenic signal transduction, meiotic recombination, and cell cycle control. The discovery of ATM should enhance understanding of AT and related syndromes and may allow the identification of AT heterozygotes, who are at increased risk of cancer.

2,729 citations


Book
Gideon Toury1
18 May 1995
TL;DR: This is an expanded and slightly revised version of the book of the same title which caused quite a stir when it was first published (1995), and reflects an additional step in an ongoing research project which was launched in the 1970s.
Abstract: This is an expanded and slightly revised version of the book of the same title which caused quite a stir when it was first published (1995). It thus reflects an additional step in an ongoing research project which was launched in the 1970s. The main objective is to transcend the limitations of using descriptive methods as a mere ancillary tool and place a proper branch of DTS at the very heart of the discipline, between the theoretical and the applied branches. Throughout the book, theoretical and methodological discussions are illustrated by an assortment of case studies, the emphasis being on the need to take whatever one wishes to focus on within the contexts which are relevant to it. Part One discusses the pivotal position of the descriptive branch within Translation Studies, and Part Two then outlines a detailed rationale for that positioning. This, in turn, supplies a framework for the case studies comprising Part Three, where a number of exemplary issues are analysed and contextualized: texts and modes of translational behaviour are situated in their cultural setting, and textual components are related to their texts and then also to the cultural constellations in which they are embedded. All this leads to Part Four, which asks what the knowledge accumulated through descriptive studies of the kind advocated in the book is likely to yield in terms of both the theoretical and the applied branches of the field. All in all: an innovative, thought-provoking book which no one with a keen interest in translation can afford to ignore.

2,621 citations


Journal ArticleDOI
TL;DR: In this article, a decentralized economy will have difficulty in fully exploiting the growth opportunities of GPT's: arms-length market transactions between the GPT and its users may result in "too little, too late" innovation.

1,772 citations


Journal ArticleDOI
TL;DR: In this article, the authors present explicit models for a symmetry breakdown in the cases of the Weyl (or homothetic) group, the SL(4, R), or the GL(4-R) covering subgroup.

1,474 citations


Proceedings ArticleDOI
20 Aug 1995
TL;DR: STM is used to provide a general highly concurrent method for translating sequential object implementations to non-blocking ones based on implementing a k-word compare&swap STM-transaction, a novel software method for supporting flexible transactional programming of synchronization operations.
Abstract: As we learn from the literature, flexibility in choosing synchronization operations greatly simplifies the task of designing highly concurrent programs. Unfortunately, existing hardware is inflexible and is at best on the level of a Load–Linked/Store–Conditional operation on a single word. Building on the hardware based transactional synchronization methodology of Herlihy and Moss, we offer software transactional memory (STM), a novel software method for supporting flexible transactional programming of synchronization operations. STM is non-blocking, and can be implemented on existing machines using only a Load–Linked/Store–Conditional operation. We use STM to provide a general highly concurrent method for translating sequential object implementations to non-blocking ones based on implementing a k-word compare&swap STM-transaction. Empirical evidence collected on simulated multiprocessor architectures shows that our method always outperforms the non-blocking translation methods in the style of Barnes, and outperforms Herlihy’s translation method for sufficiently large numbers of processors. The key to the efficiency of our software-transactional approach is that unlike Barnes style methods, it is not based on a costly “recursive helping” policy.

1,369 citations


Posted Content
TL;DR: In this paper, the authors explore changes in university patenting behavior between 1965 and 1988, and show that university patents have increased 15-fold while real university research spending almost tripled.
Abstract: This paper explores changes in university patenting behavior between 1965 and 1988. We show that university patents have increased 15-fold while real university research spending almost tripled. The causes of this increase are unclear, but may include increased focus on commercially relevant technologies, increased industry funding of university research, a 1980 change in federal law that facilitated patenting of results from federally funded research, and the widespread creation of formal technology licensing offices at universities. Up until approximately the mid-1980s, university patents were more highly cited, and were cited by more technologically diverse patents, than a random sample of all patents. This difference is consistent with the notion that university inventions are more important and more basic than the average invention. The differences between the two groups disappeared, however, in the middle part of the 1980s, partly due to a decline in the citation rates for all universities, and partly due to an increasing share of patents going to smaller institutions, whose patents are less highly cited throughout this period. Moreover at both large and small institutions there was a large increase in the fraction of university patents receiving zero citations. Our results suggest that the rate of increase of important patents from universities is much less than the overall rate of increase of university patenting in the period covered by our data.

1,075 citations


Book
01 Jan 1995
TL;DR: A close to linear bound on the maximum length of Davenport--Schinzel sequences enable us to derive sharp bounds on the combinatorial structure underlying various geometric problems, which in turn yields efficient algorithms for these problems.
Abstract: An $(n,s)$ Davenport--Schinzel sequence, for positive integers $n$ and $s$, is a sequence composed of $n$ symbols with the properties that no two adjacent elements are equal, and that it does not contain, as a (possibly non-contiguous) subsequence, any alternation $a \cdots b \cdots a \cdots b \cdots$ of length $s+2$ between two distinct symbols $a$ and $b$. The close relationship between Davenport--Schinzel sequences and the combinatorial structure of lower envelopes of collections of functions make the sequences very attractive, because a wide variety of geometric problems can be formulated in terms of lower envelopes. A close to linear bound on the maximum length of Davenport--Schinzel sequences enable us to derive sharp bounds on the combinatorial structure underlying various geometric problems, which in turn yields efficient algorithms for these problems. This paper gives a comprehensive survey on the theory of Davenport--Schinzel sequences and their geometric applications.

1,052 citations


Journal ArticleDOI
27 Jan 1995-Science
TL;DR: The phenomenology of these patterns, and of the shapes of their constituent domains, is reviewed here from a point of view that interprets these patterns as a manifestation of modulated phases.
Abstract: A wide variety of two- and three-dimensional physical-chemical systems display domain patterns in equilibrium. The phenomenology of these patterns, and of the shapes of their constituent domains, is reviewed here from a point of view that interprets these patterns as a manifestation of modulated phases. These phases are stabilized by competing interactions and are characterized by periodic spatial variations of the pertinent order parameter, the corresponding modulation period generally displaying a dependence on temperature and other external fields. This simple picture provides a unifying framework to account for striking and substantial similarities revealed in the prevalent "stripe" and "bubble" morphologies as well as in commonly observed, characteristic domain-shape instabilities. Several areas of particular current interest are discussed.

970 citations


Journal ArticleDOI
TL;DR: A novel randomized method, the method of color-coding for finding simple paths and cycles of a specified length k, and other small subgraphs, within a given graph G = (V,E), which can be derandomized using families of perfect hash functions.
Abstract: We describe a novel randomized method, the method of color-coding for finding simple paths and cycles of a specified length k, and other small subgraphs, within a given graph G = (V,E). The randomized algorithms obtained using this method can be derandomized using families of perfect hash functions. Using the color-coding method we obtain, in particular, the following new results: • For every fixed k, if a graph G = (V,E) contains a simple cycle of size exactly k, then such a cycle can be found in either O(V ) expected time or O(V ω log V ) worst-case time, where ω < 2.376 is the exponent of matrix multiplication. (Here and in what follows we use V and E instead of |V | and |E| whenever no confusion may arise.) • For every fixed k, if a planar graph G = (V,E) contains a simple cycle of size exactly k, then such a cycle can be found in either O(V ) expected time or O(V log V ) worst-case time. The same algorithm applies, in fact, not only to planar graphs, but to any minor closed family of graphs which is not the family of all graphs. • If a graph G = (V,E) contains a subgraph isomorphic to a bounded tree-width graph H = (VH , EH) where |VH | = O(log V ), then such a copy of H can be found in polynomial time. This was not previously known even if H were just a path of length O(log V ). These results improve upon previous results of many authors. The third result resolves in the affirmative a conjecture of Papadimitriou and Yannakakis that the LOG PATH problem is in P. We can show that it is even in NC.

Journal ArticleDOI
01 Jun 1995-Sleep
TL;DR: The data suggest that actigraphy, despite its limitations, may be a useful, cost-effective method for assessing specific sleep disorders, such as insomnia and schedule disorders, and for monitoring their treatment process.
Abstract: This paper, which has been reviewed and approved by the Board of Directors of the American Sleep Disorders Association, provides the background for the Standards of Practice Committee's parameters for the practice of sleep medicine in North America The growing use of activity-based monitoring (actigraphy) in sleep medicine and sleep research has enriched and challenged traditional sleep-monitoring techniques This review summarizes the empirical data on the validity of actigraphy in assessing sleep-wake patterns and assessing clinical and control groups ranging in age from infancy to elderly An overview of sleep-related actigraphic studies is also included Actigraphy provides useful measures of sleep-wake schedule and sleep quality The data also suggest that actigraphy, despite its limitations, may be a useful, cost-effective method for assessing specific sleep disorders, such as insomnia and schedule disorders, and for monitoring their treatment process Methodological issues such as the proper use of actigraphy and possible artifacts have not been systematically addressed in clinical research and practice

Journal ArticleDOI
TL;DR: In this article, an ensemble-averaged statistics at constant phase of the turbulent near-wake flow (Reynolds number ≈ 21400 around a square cylinder) were obtained from two-component laser-Doppler measurements.
Abstract: Ensemble-averaged statistics at constant phase of the turbulent near-wake flow (Reynolds number ≈ 21400 around a square cylinder have been obtained from two-component laser-Doppler measurements. Phase was defined with reference to a signal taken from a pressure sensor located at the midpoint of a cylinder sidewall. The distinction is drawn between the near wake where the shed vortices are ‘mature’ and distinct and a base region where the vortices grow to maturity and are then shed. Differences in length and velocity scales and vortex celerities between the flow around a square cylinder and the more frequently studied flow around a circular cylinder are discussed. Scaling arguments based on the circulation discharged into the near wake are proposed to explain the differences. The relationship between flow topology and turbulence is also considered with vorticity saddles and streamline saddles being distinguished. While general agreement with previous studies of flow around a circular cylinder is found with regard to essential flow features in the near wake, some previously overlooked details are highlighted, e.g. the possibility of high Reynolds shear stresses in regions of peak vorticity, or asymmetries near the streamline saddle. The base region is examined in more detail than in previous studies, and vorticity saddles, zero-vorticity points, and streamline saddles are observed to differ in importance at different stages of the shedding process.

Journal ArticleDOI
TL;DR: The molecular cloning of a cDNA contig spanning the complete open reading frame of the ATM gene provides useful clues to the function of this protein, and furthers understanding of the pleiotropic nature of the A-T mutations.
Abstract: Ataxia-telangiectasia (A-T) is an autosomal recessive disorder involving cerebellar degeneration, immunodeficiency radiation sensitivity, and cancer predisposition. A-T heterozygotes are moderately cancer prone. The A-T gene, designated ATM, was recently identified in our laboratory by positional cloning, and a partial cDNA clone was found to encode a polypeptide with a PI-3 kinase domain. We report here the molecular cloning of a cDNA contig spanning the complete open reading frame of the ATM gene. The predicted protein of 3056 amino acids shows significant sequence similarities to several large proteins in yeast, Drosophila and mammals, all of which share the PI-3 kinase domain. Many of these proteins are involved in the detection of DNA damage and the control of cell cycle progression. Mutations in their genes confer a variety of phenotypes with features similar to those observed in human A-T cells. The complete sequence of the ATM gene product provides useful clues to the function of this protein, and furthers understanding of the pleiotropic nature of the A-T mutations.

Posted Content
TL;DR: In this article, the authors investigate whether investors price and the real option to abandon the firm for its liquidation value, and they find strong support for the major empirical predictions of abandonment put option theory.
Abstract: We investigate whether investors price and the real option to abandon the firm for its liquidation value. Theory prices this real option as an American put with both a stochastic strike price (liquidation value) and a stochastic value of the underlying security (the value of cash flows). The major empirical implications are that firm value increases in liquidation value, after controlling for expected going-concern cash flows, and that more generalizable assets produce more abandonment option value. We use both discounted analyst forecasts of future earnings and industry-median cash flow multipliers to proxy for expected going-concern cash flows, and we rely on prior literature to categorize assets as more or less specialized. Using these measures, we find strong support for the major empirical predictions of abandonment put option theory.

Journal ArticleDOI
TL;DR: Controlled-release melatonin replacement therapy effectively improves sleep quality in this population of elderly people and may have an important role in the high frequency of insomnia among elderly people.

Journal ArticleDOI
TL;DR: In this paper, a lattice definition of QCD based on chiral defect fermions is discussed in detail, which involves (infinitely) many heavy regulator fields, realized through the introduction of an unphysical fifth dimension.

Journal ArticleDOI
TL;DR: An attention operator based on the intuitive notion of symmetry, which generalized many of the existing methods of detecting regions of interest is presented, a low-level operator that can be applied successfully without a priori knowledge of the world.
Abstract: Active vision systems, and especially foveated vision systems, depend on efficient attentional mechanisms. We propose that machine visual attention should consist of both high-level, context-dependent components, and low-level, context free components. As a basis for the context-free component, we present an attention operator based on the intuitive notion of symmetry, which generalized many of the existing methods of detecting regions of interest. It is a low-level operator that can be applied successfully without a priori knowledge of the world. The resultingsymmetry edge map can be applied in various low, intermediate-and high- level tasks, such as extraction of interest points, grouping, and object recognition. In particular, we have implemented an algorithm that locates interest points in real time, and can be incorporated in active and purposive vision systems. The results agree with some psychophysical findings concerning symmetry as well as evidence concerning selection of fixation points. We demonstrate the performance of the transform on natural, cluttered images.

Journal ArticleDOI
TL;DR: This study suggests that direct activation of p21ras may be a central mechanism by which a variety of redox stress stimuli transmit their signal to the nucleus.

Journal ArticleDOI
TL;DR: In this article, the authors classify variables affecting consumer recycling behavior into four theoretical groups: intrinsic incentives, extrinsic incentives, internal facilitators, and external facilitators and propose a model and provide practical implications for motivating consumer participation in waste separation programs.
Abstract: This article classifies variables affecting consumer recycling behavior into four theoretical groups: intrinsic incentives, extrinsic incentives, internal facilitators, and external facilitators. These clusters of variables, taken from 67 empirical studies culled from published and unpublished research, were metanalyzed. Of these sets of variables, the strongest predictors of recycling are internal facilitators: specifically, consumer knowledge and commitment to recycling best predicts propensity to recycle. External incentives—in particular, monetary rewards and social influence—are the next best predictors. One external facilitator that significantly relates to recycling is frequency of collection. Finally, these relationships are further examined to isolate the impact of moderator variables. Three variables are shown to have some moderating effects: sample size, when the study was done, and mode of data collection. Based on the results, the authors propose a model and provide practical implications for motivating consumer participation in waste separation programs.

Journal ArticleDOI
TL;DR: The diffusion model developed by Bass Bass, F. M. 1969 as discussed by the authors represents a pattern or regularity that has been shown to repeat over many new products and services in many countries and over a variety circumstances.
Abstract: The diffusion model developed by Bass Bass, F. M. 1969. A new product growth model for consumer durables. Management Sci.15January 215--227. constitutes an empirical generalization. It represents a pattern or regularity that has been shown to repeat over many new products and services in many countries and over a variety circumstances. Numerous and various applications of the model have lead to further generalizations. Modifications and extensions of the model have lead to further generalizations. In addition to the empirical generalizations that stem from the model, we discuss here some of the managerial applications of the model.

Journal ArticleDOI
TL;DR: The modeling approach is applied to study the diffusion of two types of software in the United Kingdom and suggests that although six of every seven software users utilized pirated copies, these pirates were responsible for generating more than 80% of new software buyers, thereby significantly influencing the legal diffusion of the software.
Abstract: Software piracy by users has been identified as the worst problem facing the software industry today. Software piracy permits the shadow diffusion of a software parallel to its legal diffusion in t...

Journal ArticleDOI
08 Sep 1995-Cell
TL;DR: Patients with the genetic disorder ataxia telangiectasia have mutations in the AT mutated (ATM) gene, which is homologous to TEL1 and the checkpoint gene MEC1, and data indicate that T EL1 and M EC1 are functionally related and that functions of the ATM gene are apparently divided between at least two S. cerevisiae homologs.

Journal ArticleDOI
TL;DR: P21ras is essential for NO-induced downstream signaling, such as NF-κB activation, and that endogenous NO can activate p21ras in the same cell, and it is suggested that NO activates p21ra by an action which mimics that of guanine nucleotide exchange factors.

Journal ArticleDOI
TL;DR: In this paper, the authors reported the first results of an extensive new study of the Galactic center stellar cluster, which strongly supported the existence of a central dark mass of 3 × 106 M☉ (density ≥ 108.5 M≉ pc-3, M/L ≥ 10 M⌉/L ⌉) within 0.14 pc of the dynamic center.
Abstract: We report the first results of an extensive new study of the Galactic center stellar cluster. The central parsec is powered by a cluster of about two dozen luminous and helium-rich blue supergiants/Wolf-Rayet stars (Teff ~ 20,000-30,000 K) with ZAMS masses up to ~100 M☉. The most likely scenario for the formation of the massive stars is a small star formation burst between 3 × 106 and 7 × 106 years ago. In this scenario the Galactic center is presently in a short-lived, post-main-sequence "wind phase." In addition, there is evidence for another star formation event about 108 years ago, as well as for recently formed massive stars that may have been transported into the central core along with orbiting gas streamers. The radial velocity dispersion of 35 early- and late-type stars with distances of 1''-12'' from Sgr A* is 154 ± 19 km s-1. Our new results strongly favor the existence of a central dark mass of ~3 × 106 M☉ (density ≥ 108.5 M☉ pc-3, M/L ≥ 10 M☉/L☉) within 0.14 pc of the dynamic center.


Journal ArticleDOI
TL;DR: Fibrous composite systems characterized by a cylindrical microgeometry and consisting of a Piezoelectric and a piezomagnetic phase with thermal effects are considered and it is shown that there are sixteen connections for a subset of twenty effective moduli.
Abstract: Fibrous composite systems characterized by a cylindrical microgeometry and consisting of a piezoelectric and a piezomagnetic phase with thermal effects are considered. These composites exhibit a magnetoelectric effect that is not present in the constituents. Exact connections are derived between the effective moduli of such systems. These relations are independent of the details of the microgeometry and of the particular choice of the averaging model. In the case of overall transverse isotropy the composite is characterized by twenty one constants. We show that there are sixteen connections for a subset of twenty effective moduli. Simple expressions are also derived for the effective constants of the composite cylinder assemblage microgeometry in such systems.

Journal ArticleDOI
01 Sep 1995-Sleep
TL;DR: It is suggested that for melatonin-deficient elderly insomniacs, melatonin replacement therapy may be beneficial in the initiation and maintenance of sleep.
Abstract: Changes in sleep-wake patterns are among the hallmarks of biological aging. Previously, we reported that impaired melatonin secretion is associated with sleep disorders in old age. In this study we investigated the effects of melatonin replacement therapy on melatonin-deficient elderly insomniacs. The study comprised a running-in, no-treatment period and four experimental periods. During the second, third and fourth periods, subjects were administered tablets for 7 consecutive days, 2 hours before desired bedtime. The tablets were either 2 mg melatonin administered as sustained-release or fast-release formulations, or an identical-looking placebo. The fifth period, which concluded the study, was a 2-month period of daily administration of 1 mg sustained-release melatonin 2 hours before desired bedtime. During each of these five experimental periods, sleep-wake patterns were monitored by wrist-worn actigraphs. Analysis of the first three 1-week periods revealed that a 1-week treatment with 2 mg sustained-release melatonin was effective for sleep maintenance (i.e. sleep efficiency and activity level) of elderly insomniacs, while sleep initiation was improved by the fast-release melatonin treatment. Sleep maintenance and initiation were further improved following the 2-month 1-mg sustained-release melatonin treatment, indicating that tolerance had not developed. After cessation of treatment, sleep quality deteriorated. Our findings suggest that for melatonin-deficient elderly insomniacs, melatonin replacement therapy may be beneficial in the initiation and maintenance of sleep.

Journal ArticleDOI
Rachel Giora1
TL;DR: In this paper, irony is viewed as a mode of indirect negation, and irony understanding involves processing both negated and implicated messages, so that the difference between them may be computed.
Abstract: In this article, irony is viewed as a mode of indirect negation. Based on this view, interpreting irony does not involve canceling the indirectly negated message and replacing it with the implicated one (as contended by, e.g., Clark & Gerrig, 1984; Grice, 1975). Rather, irony understanding involves processing both the negated and implicated messages, so that the difference between them may be computed. This view thus differs from the view which assumes that irony involves only one interpretation (e.g., Gibbs, 1986a; Sperber & Wilson, 1981; Wilson & Sperber, 1992). Holding that irony activates both the literal/explicit and the ironic/implicated meanings predicts that irony will be more difficult to understand than a nonironic use of the same utterance. Reanalysis of previous findings (Gibbs, 1986a) evinces that irony takes longer to process than nonironic use of the same utterance. Though irony is more difficult to understand than nonironic language, speakers apply this mode for certain communicative goals...

Journal ArticleDOI
TL;DR: This article found that those who choose to leave their employment to become entrepreneurs earn substantially less on average then those whose employment status did not change and who remained paid employees throughout the survey period.