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Showing papers by "Tel Aviv University published in 1994"


Journal ArticleDOI
TL;DR: In the conventional approach to quantum mechanics, indeterminism is an axiom and non-locality is a theorem as discussed by the authors, but in this paper, we consider inverting the logical order, making non-local non-quantum correlations, preserving relativistic causality, can violate the CHSH inequality more strongly than any quantum correlations.
Abstract: In the conventional approach to quantum mechanics, indeterminism is an axiom and nonlocality is a theorem. We consider inverting the logical order, making nonlocality an axiom and indeterminism a theorem. Nonlocal “superquantum” correlations, preserving relativistic causality, can violate the CHSH inequality more strongly than any quantum correlations.

1,511 citations


Journal ArticleDOI
TL;DR: In this article, the authors proposed a method for computing tax rates using national accounts and revenue statistics. And they constructed time series of tax rates for large industrial countries, identifying the revenue raised by different taxes at the general government level and defining aggregate measures of the corresponding tax bases.

1,005 citations


Posted Content
TL;DR: In this article, the authors study the competition between two political parties for seats in a parliament and show that each party is induced to behave as if it were maximizing a weighted sum of the aggregate welfares of informed voters and members of special interest groups.
Abstract: We study the competition between two political parties for seats in a parliament. The parliament will set two types of policies: ideological and non-ideological. The parties have fixed positions on the ideological issues, but choose their non-ideological platforms to attract voters and campaign contributions. In this context, we ask: How do the equilibrium contributions from special interest groups influence the platforms of the parties? We show that each party is induced to behave as if it were maximizing a weighted sum of the aggregate welfares of informed voters and members of special interest groups. The party that is expected to win a majority of seats caters more to the special interests.

824 citations


Journal ArticleDOI
TL;DR: A literature review supports the conclusion that a clear physical distinction between relevant and irrelevant information is not sufficient to prevent irrelevant processing; early selection also requires that the perceptual load of the task be sufficiently high to exceed the upper limit of available attentional resources.
Abstract: In this paper, we propose that the debate concerning the locus of attentional selection can be resolved by specifying the conditions under which early selection is possible. In the first part, we present a theoretical discussion that integrates aspects from structural and capacity approaches to attention and suggest that perceptual load is a major factor in determining the locus of selection. In the second part, we present a literature review that examines the conditions influencing the processing of irrelevant information. This review supports the conclusion that a clear physical distinction between relevant and irrelevant information is not sufficient to prevent irrelevant processing; early selection also requires that the perceptual load of the task be sufficiently high to exceed the upper limit of available attentional resources.

815 citations


Journal ArticleDOI
TL;DR: A matching algorithm using surface complementarity between receptor and ligand protein molecules is outlined, and it is shown that out of the 16 protein‐protein complexes tried, 15 were successfully docked, including two immunoglobulins.
Abstract: A matching algorithm using surface complementarity between receptor and ligand protein molecules is outlined. The molecular surfaces are represented by "critical points," describing holes and knobs. Holes (maxima of a shape function) are matched with knobs (minima). This simple and appealing surface representation has been previously described by Connolly [(1986) Biopolymers, Vol. 25, pp. 1229-1247]. However, attempts to implement this description in a docking scheme have been unsuccessful (e.g., Connolly, ibid.). In order to decrease the combinatorial complexity, and to make the execution time affordable, four critical hole/knob point matches were sought. This approach failed since some bound interfaces are relatively flat and do not possess four critical point matches. On the otherhand, matchings of fewer critical points require a very time-consuming, full conformational (grid) space search [Wang, (1991) Journal of Computational Chemistry, Vol. 12, pp. 746-750]. Here we show that despite the initial failure of this approach, with a simple and straightforward modification in the matching algorithm, this surface representation works well. Out of the 16 protein-protein complexes we have tried, 15 were successfully docked, including two immunoglobulins. The entire molecular surfaces were considered, with absolutely no additional information regarding the binding sites. The whole process is completely automated, with no manual intervention, either in the input atomic coordinate data, or in the matching. We have been able to reach this level of performance with the hole/knob surface description by using pairs of critical points along with their surface normals in the calculation of the transformation matrix. The success of this approach suggests that future docking methods should use geometric docking as the first screening filter.(ABSTRACT TRUNCATED AT 250 WORDS)

787 citations


Journal ArticleDOI
Lev Vaidman1
TL;DR: The recent result of Bennett of teleportation of an unknown quantum state is obtained in the framework of nonlocal measurements proposed by Aharonov and Albert, and the latter method is generalized to the teleportation of a quantum state of a system with continuous variables.
Abstract: The recent result of Bennett et al. [Phys. Rev. Lett. 70, 1895 (1993)] of teleportation of an unknown quantum state is obtained in the framework of nonlocal measurements proposed by Aharonov and Albert [Phys. Rev. D 21, 3316 (1980); 24, 359 (1981)]. The latter method is generalized to the teleportation of a quantum state of a system with continuous variables.

736 citations


Journal ArticleDOI
03 Mar 1994-Nature
TL;DR: It is shown that a simple model of bacterial growth can reproduce the salient features of the observed growth patterns, and incorporates random walkers, representing aggregates of bacteria, which move in response to gradients in nutrient concentration and communicate with each other by means of chemotactic 'feedback.
Abstract: Bacterial colonies must often cope with unfavourable environmental conditions. To do so, they have developed sophisticated modes of cooperative behaviour. It has been found that such behaviour can cause bacterial colonies to exhibit complex growth patterns similar to those observed during non-equilibrium growth processes in non-living systems; some of the qualitative features of the latter may be invoked to account for the complex patterns of bacterial growth. Here we show that a simple model of bacterial growth can reproduce the salient features of the observed growth patterns. The model incorporates random walkers, representing aggregates of bacteria, which move in response to gradients in nutrient concentration and communicate with each other by means of chemotactic 'feedback'. These simple features allow the colony to respond efficiently to adverse growth conditions, and generate self-organization over a wide range of length scales.

557 citations


Journal ArticleDOI
TL;DR: Convolution, filtering, and multiplexing of signals in fractional domains are discussed, revealing that under certain conditions one can improve on the special cases of these operations in the conventional space and frequency domains.
Abstract: A concise introduction to the concept of fractional Fourier transforms is followed by a discussion of their relation to chirp and wavelet transforms. The notion of fractional Fourier domains is developed in conjunction with the Wigner distribution of a signal. Convolution, filtering, and multiplexing of signals in fractional domains are discussed, revealing that under certain conditions one can improve on the special cases of these operations in the conventional space and frequency domains. Because of the ease of performing the fractional Fourier transform optically, these operations are relevant for optical information processing.

499 citations


Journal ArticleDOI
TL;DR: One of these subunits comprises a distinctive new class of noncatalytic scaffolding polypeptide, which selectively integrates the various cellulase and xylanase subunits into the cohesive complex.

458 citations


Journal ArticleDOI
TL;DR: Progress has been made on improving the result of biliary reconstruction after OLTx, and if significant additional improvement in patient and graft survival are to be obtained, the technical performance of OLTx must continue to improve.
Abstract: Objective This study analyzed the incidence and timing of biliary tract complications after orthotopic liver transplantation (OLTx) in 1792 consecutive patients. These results were then compared with those of previously reported series. Finally, recommendations were made on appropriate management strategies. Summary background data Technical complications after OLTx have a significant impact on patient and graft survival. One of the principal technical advances has been the standardization of techniques for biliary reconstruction. Nonetheless, biliary complications still occur. A 1983 report from the University of Pittsburgh reported biliary complications in 19% of all transplants, and an update in 1987 reported biliary complications in 13.2% of transplants. Methods The medical records of all patients who underwent liver transplantation and were hospitalized between January 1, 1988 and July 31, 1991 were reviewed. The case material consisted of the medical records of 217 patients treated for 245 biliary complications. Results Primary biliary continuity was established by either choledochocholedochostomy over a T-tube (C-C, n = 129) or a Roux-en-Y choledochojejunostomy with an internal stent (C-RY, n = 85). The overall incidence for biliary complication in this large series was 11.5%. Strictures (n = 93) and bile leak (n = 58) were the most common complications (69.6%). Most biliary complications (n = 143, 66%) occurred within the first 3 months after surgery. In general, leaks occurred early, and strictures developed later. Bile leaks were equally frequent in both C-C and C-RY (27.1% and 25.9%, respectively); strictures were more common after a C-RY type of reconstruction (36.4% and 52.9%, respectively). Twenty-one patients died, an incidence of 9.6%. Fifteen of the 21 biliary-related deaths were among patients treated for rejection before the recognition of biliary tract pathologic findings. Conclusions Progress has been made on improving the results of biliary reconstruction after OLTx. Nonetheless, patients continue to experience biliary complications after OLTx, and these complications cause considerable loss of grafts and life. If significant additional improvement in patient and graft survival are to be obtained, the technical performance of OLTx must continue to improve.

451 citations


Journal ArticleDOI
TL;DR: The present Commentary proposes that interaction is inherent in the neural architecture of the basal ganglia-thalamocortical circuits, and tentatively identified a motor, an associative, and a limbic split circuit, each containing a closed circuit and an open pathway.

Journal ArticleDOI
TL;DR: Mucoid strains of Escherichia coli, Acinetobacter calcoaceticus, and Erwinia stewartii were significantly more resistant to desiccation than corresponding isogenic nonmucoid mutants, even in colonies containing both cell types.
Abstract: Mucoid strains of Escherichia coli, Acinetobacter calcoaceticus, and Erwinia stewartii were significantly more resistant to desiccation than corresponding isogenic nonmucoid mutants (survival rates of up to 35% in mucoid strains and between 0.7 and 5% in nonmucoid variants), even in colonies containing both cell types. Desiccation was found to bring about an induction of beta-galactosidase in Lon strains of E. coli K-12 carrying transcriptional lac fusions in the capsule biosynthetic (cps) regulon. This induction was dependent on the transcriptional activators RcsA and RcsB. Induction was lower in cells carrying mutations in the membrane sensor protein RcsC.

Journal ArticleDOI
Ram Zamir1, K. Feder1
27 Jun 1994
TL;DR: In entropy-coded dithered quantization, which can be modeled accurately as passing the source through an additive noise channel, this limit behavior implies that for large lattice dimension both the error and the bit rate approach theerror and the information rate of an additive white Gaussian noise (AWGN) channel.
Abstract: We present several results regarding the properties of a random vector, uniformly distributed over a lattice cell. This random vector is the quantization noise of a lattice quantizer at high resolution, or the noise of a dithered lattice quantizer at all distortion levels. We find that for the optimal lattice quantizers this noise is wide-sense-stationary and white. Any desirable noise spectra may be realized by an appropriate linear transformation ("shaping") of a lattice quantizer. As the dimension increases, the normalized second moment of the optimal lattice quantizer goes to 1/2/spl pi/e, and consequently the quantization noise approaches a white Gaussian process in the divergence sense. In entropy-coded dithered quantization, which can be modeled accurately as passing the source through an additive noise channel, this limit behavior implies that for large lattice dimension both the error and the bit rate approach the error and the information rate of an additive white Gaussian noise (AWGN) channel.

Journal ArticleDOI
TL;DR: The nuclear dependence of the diffractive cross sections provides important tests of color transparency as well as constraints on the shadowing of the gluon structure functions and the longitudinal structure functions of nuclei.
Abstract: We demonstrate that the distinctive features of the forward differential cross section of diffractive leptoproduction of a vector meson can be legitimately calculated in perturbative QCD in terms of the light-cone [ital q[bar q]] wave function of the vector meson and the gluon distribution of the target. In particular, we calculate the [ital Q][sup 2] and nuclear dependence of the diffractive leptoproduction of vector mesons and estimate the cross section. The production of longitudinally polarized vector mesons by longitudinally polarized virtual photons is predicted to be the dominant component, yielding a cross section behaving as [ital Q][sup [minus]6]. The nuclear dependence of the diffractive cross sections, which follows from a factorization theorem in perturbative QCD, provides important tests of color transparency as well as constraints on the shadowing of the gluon structure functions and the longitudinal structure functions of nuclei.

Journal ArticleDOI
TL;DR: Biomechanical problems are analyzed, and a recommended clinical approach is presented, suggesting that the post did not improve the resistance to fracture during occlusion and did not support the restoration.
Abstract: Various concepts for dental treatment have been established without appropriate documentation, such as restoration of endodontically treated teeth. Some researchers and dentists strongly recommend including a post with the restoration to strengthen the root. Other studies have indicated that posts may substantially weaken the roots and should be avoided. An additional approach suggested that the post did not improve the resistance to fracture during occlusion and did not support the restoration. Biomechanical problems are analyzed, and a recommended clinical approach is presented.


Journal ArticleDOI
TL;DR: In this paper, the p-system is reformulated as a kinetic equation, using an additional kinetic variable, and the advection velocity is now a combination of the macroscopic and kinetic velocities.
Abstract: We consider the 2 x 2 hyperbolic system of isentropic gas dynamics, in both Eulerian or Lagrangian variables (also called the p-system). We show that they can be reformulated as a kinetic equation, using an additional kinetic variable. Such a formulation was first obtained by the authors in the case of multidimensio nal scalar conservation laws. A new phenomenon occurs here, namely that the advection velocity is now a combination of the macroscopic and kinetic velocities. Various applications are given: we recover the invariant regions, deduce new L°° estimates using moments lemma and prove L°° — w* stability for 7 > 3.

Proceedings ArticleDOI
23 May 1994
TL;DR: A new model of learning probability distributions from independent draws is introduced, inspired by the popular Probably Approximately Correct (PAC) model for learning boolean functions from labeled examples, in the sense that it emphasizes efficient and approximate learning, and it studies the learnability of restricted classes of target distributions.
Abstract: We introduce and investigate a new model of learning probability distributions from independent draws. Our model is inspired by the popular Probably Approximately Correct (PAC) model for learning boolean functions from labeled examples [24], in the sense that we emphasize efficient and approximate learning, and we study the learnability of restricted classes of target distributions. The dist ribut ion classes we examine are often defined by some simple computational mechanism for transforming a truly random string of input bits (which is not visible to the learning algorithm) into the stochastic observation (output) seen by the learning algorithm. In this paper, we concentrate on discrete distributions over {O, I}n. The problem of inferring an approximation to an unknown probability distribution on the basis of independent draws has a long and complex history in the pattern recognition and statistics literature. For instance, the problem of estimating the parameters of a Gaussian density in highdimensional space is one of the most studied statistical problems. Distribution learning problems have often been investigated in the context of unsupervised learning, in which a linear mixture of two or more distributions is generating the observations, and the final goal is not to model the distributions themselves, but to predict from which distribution each observation was drawn. Data clustering methods are a common tool here. There is also a large literature on nonpararnetric density estimation, in which no assumptions are made on the unknown target density. Nearest-neighbor approaches to the unsupervised learning problem often arise in the nonparametric setting. While we obviously cannot do justice to these areas here, the books of Duda and Hart [9] and Vapnik [25] provide excellent overviews and introductions to the pattern recognition work, as well as many pointers for further reading. See also Izenman’s recent survey article [16]. Roughly speaking, our work departs from the traditional statistical and pattern recognition approaches in two ways. First, we place explicit emphasis on the comput ationrd complexity of distribution learning. It seems fair to say that while previous research has provided an excellent understanding of the information-theoretic issues involved in dis-

Proceedings ArticleDOI
23 May 1994
TL;DR: It is proved that an algorithm due to Kushilevitz and Mansour can be used to weakly learn DNF using membership queries in polynomial time, with respect to the uniform distribution on the inputs, and it is obtained that DNF expressions and decision trees are not evenWeakly learnable with any unproven assumptions.
Abstract: We present new results, both positive and negative, on the well-studied problem of learning disjunctive normal form (DNF) expressions. We first prove that an algorithm due to Kushilevitz and Mansour [16] can be used to weakly learn DNF using membership queries in polynomial time, with respect to the uniform distribution on the inputs. This is the first positive result for learning unrestricted DNF expressions in polynomial time in any nontrivial formal model of learning. It provides a sharp contrast with the results of Kharitonov [15], who proved that ACO is not efficiently learnable in the same model (given certain plausible cryptographic assumptions). We also present efficient learning algorithms in various models for the read-k and SAT-k subclasses of DNF. For our negative results, we turn our attention to the recently introduced statistical query model of learning [11]. This model is a restricted version of the popular Probably Approximately Correct (PAC) model [23], and practically every class known to be efficiently learnable in the PAC model is in fact learnable in the statistical query model [11]. Here we give a general characterization of the complexity of statistical query learning in terms of the number of uncorrelated functions in the concept class. This is a distributiondependent quantity yielding upper and lower bounds on the number of st atistical queries required for learning on any input distribution. As a corollary, we obtain that DNF expressions and decision trees are not even weakly learnable with ●This research M sponsored in part by the Wr]ght Laboratory, Aeronautical Systems Center, Air Force Materiel Command, USAF, and the Advanced Research Projects Agency (ARPA) under grant number F33615-93-1-1330 Support also M sponsored by the National Sc]ence Foundation under Grant No CC-91 19319. Blum also supported m part by NSF National Young Investigator grant CCR9357793 Views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing official po!lcles or endorsements, either expressed or implied, of Wright Laboratory or the United States Government, or NSF tcontact ~“thor Address: AT&T Bell Laboratcmes, Room 2A423, 600 Mountain Avenue, P.O. Box 636, Murray Hill, NJ 07974 Electronic mail. mkearns@research .at t corn ~Thi~ research ~a~ ~“pported in p~~t by The Israel science Foun. datlon administered by The Israel Academy of Sc]ence and Humanities and by a grant of the Israeli Ministry of Science and Technology Permission to co y without fee all or part of this material is granted provided%atthe copies are not madeordistrftrutectfor direct commercial advantage, the ACM copyright notice and the title of the publication and its date appear, and notice is given that copying is by permission of the Association of Computing Machinery. To copy otherwise, or to republish, requires a fee ancf/or specific permission. STOC 945/94 Montreal, Quebec, Canada Q 1994 ACM 0-89791 -663-8/94/0005..$3.50 respect to the uniform input distribution in polynomial time in the statistical query model. This result is informationtheoretic and therefore does not rely on any unproven assumptions. It demonstrates that no simple modification of the existing algorithms in the computaticmal learning theory literature for learning various restricted forms of DNF and decision trees from passive random examples (and also several algorithms proposed in the experimental machine learning communities, such as the ID3 algorithm for decision trees [22] and its variants) will solve the general problem. The unifying tool for all of our results is the Fourier analysis of a finite class of boolean functions 011 the hypercube.

Journal ArticleDOI
TL;DR: This work presents simple heuristic procedures for constructing tours, for a variety of neighborhood types, whose length is guaranteed to be within a constant factor of the length of an optimal tour.

Journal ArticleDOI
TL;DR: Whether RAP occurs following mucoperiosteal flap surgery in the jaw bone is explored and large areas of radiolucency which correlated to massive resorption of the alveolar bone, as well as areas in the bone proper are revealed.
Abstract: Striking remodeling activity occurs adjacent to the site of injury in orthopedic surgery. This reaction has been described as regional accelerated phenomenon (RAP), as it speeds up the healing stage. The phenomenon is a transient burst of localized remodeling process following surgical wounding of cortical bone. We explored whether RAP occurs following mucoperiosteal flap surgery in the jaw bone. Mucoperiosteal flaps were performed on 60 Wistar rats, either only on the buccal aspect or both on buccal and lingual aspects of the mandible. The surgical procedure lasted an average of 30 seconds and the flap was readapted without sutures. The rats were sacrificed at 3, 7, 10, 14, 21, and 120 days. High resolution x-ray microradiography of 1 to 1.5 mm thick ground sections between premolar and molar regions of the mandible were analyzed and revealed large areas of radiolucency which correlated to massive resorption of the alveolar bone, as well as areas in the bone proper. The RAP was observed as early as 10 days in the treated side group. Striking resorption of the cortical bone, both on the surface and the bone proper, occurred on the periodontal aspect of the crestal bone leading to widening of the periodontal ligament space, where a mucoperiosteal flap was performed on the buccal aspect. The resorption was more prominent when a mucoperiosteal flap was performed both on the lingual and buccal aspect. The alveolar bone recovered almost to control levels 120 days after surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal ArticleDOI
TL;DR: Oral malodor was not associated with periodontitis, indicating that a large proportion of individuals with oral malodor are periodontally healthy and that the mucosal surface of the tongue is a major site of Oral malodor production.
Abstract: Associations between oral malodor, measures of periodontal disease, and trypsin-like activity of periodontal pathogens on tongue and teeth were examined in 127 subjects. Volatile sulphur compound (VSC) measurements were made with a portable sulphide monitor; oral malodor was also estimated by organoleptic methods. Measurements repeated one week apart indicated that steady-state VSC levels (r = 0.72; P = 0.0001) and peak VSC levels (r = 0.63; P = 0.0001) were reproducible but these r values were not significantly different (P > 0.1). There was a significant correlation between tongue odor and peak VSC levels (r = 0.40; P = 0.0001) and between tongue odor and whole mouth organoleptic measures (r = 0.55; P = 0.0001). To study the effect of reducing microbial colonization on oral malodor, chlorhexidine gluconate (0.2%) rinsing was prescribed for 7 days. Reductions of VSC levels were significant for both peak (37%) and steady-state (41%) data (P = 0.0001). Anaerobic periodontal pathogens on the tongue estimated by the proportions of positive BANA tests were reduced 19% (P = 0.001) and this was concomitant with a 40% (P = 0.0001) decrease in organoleptic measurement of the tongue dorsum. Mean pH measurements of the tongue dorsum showed large reductions from 6.9 initially to 6.3 post-treatment (P = 0.0001). Subjects were divided into periodontitis/no periodontitis based on periodontal inflammation and probing depth (> or = 5 mm). Of the 37 subjects with periodontitis, 23 had oral malodor whereas 52 out of 90 periodontally healthy subjects exhibited malodor. Chi square analysis comparing halitosis in subjects with and without periodontitis showed no statistically significant association (chi 2 = 0.208; P 0.65) between these two factors although the intensity of malodor as based on VSC concentration in periodontally healthy subjects was 19% less (mean = 111 ppb) than in subjects with periodontitis (mean = 136 ppb). The odds ratio was 1.2, indicating that oral malodor was not associated with periodontitis. These data indicate that a large proportion of individuals with oral malodor are periodontally healthy and that the mucosal surface of the tongue is a major site of oral malodor production.

Journal ArticleDOI
TL;DR: It is shown that for every group G of order n, and for a set S of c(δ) log n random elements in the group, the expected value of the second largest eigenvalue of the normalized adjacency matrix of the Cayley graph X(G, S) is at most (1 - δ).
Abstract: For every 1 > δ > 0 there exists a c = c(δ) > 0 such that for every group G of order n, and for a set S of c(δ) log n random elements in the group, the expected value of the second largest eigenvalue of the normalized adjacency matrix of the Cayley graph X(G, S) is at most (1 - δ). This implies that almost every such a graph is an ϵ(δ)-expander. For Abelian groups this is essentially tight, and explicit constructions can be given in some cases. © 1994 John Wiley & Sons, Inc.

Journal ArticleDOI
TL;DR: The most common location of the metastatic tumors was the mandible, with the molar area the most frequent site involved and in about 30% of cases the oral lesion was the first sign of the malignant disease.
Abstract: A review of the English language literature revealed 390 well-documented cases of metastatic lesions to the jawbones. Most metastatic lesions were diagnosed in patients in their fifth to seventh decade. The primary site differed between the genders: for women, it was the breast followed by the adrenal, colo-rectum, female genital organs and thyroid; for men, it was the lung, followed by the prostate, kidney, bone and adrenal. The most common location of the metastatic tumors was the mandible, with the molar area the most frequent site involved. In about 30% of cases the oral lesion was the first sign of the malignant disease. The present data are compared with those of metastatic tumors to the oral mucosa and a view on the possible pathogenesis is presented.

Journal ArticleDOI
TL;DR: It is shown that the method of radial basis functions provides a powerful mechanism for processing facial expressions and is applicable to other elastic objects as well.

Book
01 Jan 1994
TL;DR: The 6th edition of the book as mentioned in this paper focuses on the key issues at the forefront of the contemporary international legal debate, as well as analysing the new armed conflicts in Syria, Ukraine and Georgia, re-examining the Kampala amendments on the crime of aggression and considering the phenomenon of 'robust' mandates of a peacekeeping force.
Abstract: War, Aggression and Self-Defence is an indispensable guide to international legal issues of war and peace, the crime of aggression, self-defence and its trigger, armed attack, and the different modalities of self-defence, as well as enforcement measures taken under the aegis of a binding decision of the Security Council. This new and fully updated 6th edition focuses on the key issues at the forefront of the contemporary international legal debate, as well as analysing the new armed conflicts in Syria, Ukraine and Georgia, re-examining the Kampala amendments on the crime of aggression and considering the phenomenon of 'robust' mandates of a peacekeeping force. Suitable for graduate and advanced undergraduate students, this market-leading book offers a wide-ranging and highly readable introduction to the legal issues surrounding war and self-defence.

Journal ArticleDOI
TL;DR: In this article, a Lagrangian framework is used for analysing reactive solute transport by a steady random velocity field, which is associated with flow through a heterogeneous porous formation, and the reaction considered is kinetically controlled sorption-desorption.
Abstract: A Lagrangian framework is used for analysing reactive solute transport by a steady random velocity field, which is associated with flow through a heterogeneous porous formation. The reaction considered is kinetically controlled sorption–desorption. Transport is quantified by the expected values of spatial and temporal moments that are derived as functions of the non-reactive moments and a distribution function which characterizes sorption kinetics. Thus the results of this study generalize the previously obtained results for transport of non-reactive solutes in heterogeneous formations (Dagan 1984; Dagan et al. 1992). The results are illustrated for first-order linear sorption reactions. The general effect of sorption is to retard the solute movement. For short time, the transport process coincides with a non-reactive case, whereas for large time sorption is in equilibrium and solute is simply retarded by a factor R = 1+Kd, where Kd is the partitioning coefficient. Within these limits, the interaction between the heterogeniety and kinetics yields characteristic nonlinearities in the first three spatial moments. Asymmetry in the spatial solute distribution is a typical kinetic effect. Critical parameters that control sorptive transport asymptotically are the ratio er between a typical reaction length and the longitudinal effective (non-reactive) dispersivity, and Kd. The asymptotic effective dispersivity for equilibrium conditions is derived as a function of parameters er and Kd. A qualitative agreement with field data is illustrated for the zero- and first-order spatial moments.


Journal ArticleDOI
TL;DR: The EtOAc extract of the whole culture medium of Vibrio parahaemolyticus, which inhabits the toxic mucus of the box fish Ostracion cubicus, afforded a new indole-derived natural product, vibrindole A, along with some known cyclic dipeptides and indoles.
Abstract: The EtOAc extract of the whole culture medium of Vibrio parahaemolyticus, which inhabits the toxic mucus of the box fish Ostracion cubicus, afforded a new indole-derived natural product, vibrindole A [1], along with some known cyclic dipeptides and indoles. The structure of 1 was determined by analysis of its physicochemical characteristics.

Journal ArticleDOI
01 Feb 1994-Pain
TL;DR: A novel hypothesis based on recent findings from experimental nerve-injury preparations is proposed that trigger stimuli set off bursts of activity in a small cluster of trigeminal ganglion (TRG) neurons that have been rendered hyperexcitable as a result of TRG or trigemINAL root damage.
Abstract: Idiosyncrasies of trigeminal neuralgia provide both clues and constraints on candidate hypotheses concerning the underlying neural mechanism. After reviewing the key clinical aspects of the disease, we propose here a novel hypothesis based on recent findings from experimental nerve-injury preparations. The hypothesis states that trigger stimuli set off bursts of activity in a small cluster of trigeminal ganglion (TRG) neurons that have been rendered hyperexcitable as a result of TRG or trigeminal root damage. Activity then spreads from this "TRG ignition focus" to encompass more widespread portions of the ganglion. After a brief period of autonomous firing (seconds to minutes), activity is quenched and a refractory period is initiated by an intrinsic suppressive (hyperpolarizing) process engaged as a result of the rapid firing. The primary abnormality resides in the TRG and trigeminal root, rather than in the skin or the CNS. Because of this, sensation is essentially normal between periods of ectopic paroxysmal TRG discharge.