Showing papers by "Bar-Ilan University published in 2008"

Learning realistic human actions from movies

Abstract: The aim of this paper is to address recognition of natural human actions in diverse and realistic video settings. This challenging but important subject has mostly been ignored in the past due to several problems one of which is the lack of realistic and annotated video datasets. Our first contribution is to address this limitation and to investigate the use of movie scripts for automatic annotation of human actions in videos. We evaluate alternative methods for action retrieval from scripts and show benefits of a text-based classifier. Using the retrieved action samples for visual learning, we next turn to the problem of action classification in video. We present a new method for video classification that builds upon and extends several recent ideas including local space-time features, space-time pyramids and multi-channel non-linear SVMs. The method is shown to improve state-of-the-art results on the standard KTH action dataset by achieving 91.8% accuracy. Given the inherent problem of noisy labels in automatic annotation, we particularly investigate and show high tolerance of our method to annotation errors in the training set. We finally apply the method to learning and classifying challenging action classes in movies and show promising results.

Volcanic carbon dioxide vents show ecosystem effects of ocean acidification

Abstract: A high-profile Royal Society report in 2005, followed by similar reports worldwide, high-lighted the fact that relatively little is known about the ecosystem effects of ocean acidification. Work to date has been largely limited to short-term experiments on isolated aspects of marine communities. Hall-Spencer et al. adopted an alternative approach, tracking the response to CO2 release from volcanic vent sites off the island of Ischia in the Bay of Naples, where ocean acidification has prevailed perhaps for centuries. Typical rocky shore communities rich in calcareous organisms thrive at normal pH, shifting to communities lacking scleractinian corals and low in sea urchin and algal numbers at low pH. The results show that such sites can act as natural experiments against which to test laboratory and modelled predictions of the effects of ocean acidification. The ecological impact of ocean acidification as a result of climate change is difficult to predict. A natural CO2 venting site is used here to demonstrate the shifts occurring in a rocky shore marine community as a result of a pH gradient. The atmospheric partial pressure of carbon dioxide ( ) will almost certainly be double that of pre-industrial levels by 2100 and will be considerably higher than at any time during the past few million years1. The oceans are a principal sink for anthropogenic CO2 where it is estimated to have caused a 30% increase in the concentration of H+ in ocean surface waters since the early 1900s and may lead to a drop in seawater pH of up to 0.5 units by 2100 (refs 2, 3). Our understanding of how increased ocean acidity may affect marine ecosystems is at present very limited as almost all studies have been in vitro, short-term, rapid perturbation experiments on isolated elements of the ecosystem4,5. Here we show the effects of acidification on benthic ecosystems at shallow coastal sites where volcanic CO2 vents lower the pH of the water column. Along gradients of normal pH (8.1–8.2) to lowered pH (mean 7.8–7.9, minimum 7.4–7.5), typical rocky shore communities with abundant calcareous organisms shifted to communities lacking scleractinian corals with significant reductions in sea urchin and coralline algal abundance. To our knowledge, this is the first ecosystem-scale validation of predictions that these important groups of organisms are susceptible to elevated amounts of . Sea-grass production was highest in an area at mean pH 7.6 (1,827 μatm ) where coralline algal biomass was significantly reduced and gastropod shells were dissolving due to periods of carbonate sub-saturation. The species populating the vent sites comprise a suite of organisms that are resilient to naturally high concentrations of and indicate that ocean acidification may benefit highly invasive non-native algal species. Our results provide the first in situ insights into how shallow water marine communities might change when susceptible organisms are removed owing to ocean acidification.

Investigation, treatment and monitoring of late-onset hypogonadism in males: ISA, ISSAM, EAU, EAA and ASA recommendations

Abstract: Demographic data clearly demonstrate that the percentage of the population in the older age group is increasing. Androgen deficiency in the aging male has become a topic of increasing interest and debate throughout the world. Cross-sectional and longitudinal data indicate that the testosterone falls progressively with age and that a significant percentage of men over the age of 60 years have serum testosterone levels that are below the lower limits of young adult (age 20–30 years) men (1–4). The principal questions raised by these observations are whether older hypogonadal men will benefit from testosterone treatment and what will be the risks associated with such intervention. The past decade has brought evidence of benefit of androgen treatment of hypogonadal men on multiple target organs and the recent studies show short-term beneficial effects of testosterone in older men that are similar to those in younger men. This has been comprehensively reviewed and summarized by the Institute of Medicine in ‘Testosterone and Aging: Clinical Research Directions’ (5). Long-term data on the effects of testosterone treatment in the older population are limited mainly to effects on body composition and bone mass (6–11). Key questions of the effects of testosterone on patient reported outcomes and functional benefits that may retard physical or mental frailty of the elderly or improve the quality of life are not yet available. Specific risk data on the prostate and cardiovascular systems are needed.

Brain drain and human capital formation in developing countries : winners and losers

Abstract: Using new data on emigration rates by education level, we examine the impact of brain drain migration on human capital formation in developing countries. We find evidence of a positive effect of skilled migration prospects on gross human capital formation in a cross-section of 127 countries. For each country of the sample we then estimate the net effect of the brain drain using counterfactual simulations. Countries combining relatively low levels of human capital and low emigration rates are shown to experience a ‘beneficial brain drain’, and conversely, there are more losers than winners, and the former tend to lose relatively more than what the latter gain.

Which h-index? — A comparison of WoS, Scopus and Google Scholar

Abstract: This paper compares the h-indices of a list of highly-cited Israeli researchers based on citations counts retrieved from the Web of Science, Scopus and Google Scholar respectively. In several case the results obtained through Google Scholar are considerably different from the results based on the Web of Science and Scopus. Data cleansing is discussed extensively.

Molecular layering of fluorinated ionic liquids at a charged sapphire (0001) surface.

Abstract: Room-temperature ionic liquids (RTILs) are promising candidates for a broad range of "green" applications, for which their interaction with solid surfaces plays a crucial role. In this high-energy x-ray reflectivity study, the temperature-dependent structures of three ionic liquids with the tris(pentafluoroethyl)trifluorophosphate anion in contact with a charged sapphire substrate were investigated with submolecular resolution. All three RTILs show strong interfacial layering, starting with a cation layer at the substrate and decaying exponentially into the bulk liquid. The observed decay length and layering period point to an interfacial ordering mechanism, akin to the charge inversion effect, which is suggested to originate from strong correlations between the unscreened ions. The observed layering is expected to be a generic feature of RTILs at charged interfaces.

Random time-scale invariant diffusion and transport coefficients.

Abstract: Single particle tracking of mRNA molecules and lipid granules in living cells shows that the time averaged mean squared displacement $\overline{{\ensuremath{\delta}}^{2}}$ of individual particles remains a random variable while indicating that the particle motion is subdiffusive. We investigate this type of ergodicity breaking within the continuous time random walk model and show that $\overline{{\ensuremath{\delta}}^{2}}$ differs from the corresponding ensemble average. In particular we derive the distribution for the fluctuations of the random variable $\overline{{\ensuremath{\delta}}^{2}}$. Similarly we quantify the response to a constant external field, revealing a generalization of the Einstein relation. Consequences for the interpretation of single molecule tracking data are discussed.

Searching for a Theory of Public Diplomacy

Abstract: This work presents and critically evaluates attempts to theorize and conceptualize public diplomacy within several disciplines, including international relations, strategic studies, diplomatic studies, public relations, and communication. It also examines research methods used to investigate public diplomacy, including models, paradigms, case studies, and comparative analysis. The work identifies promising directions as well as weaknesses and gaps in existing knowledge and methodology and outlines a new research agenda. The presented analysis and examples suggest that only a systematic multidisciplinary effort and close collaboration between researchers and practitioners can lead to a coherent theory of public diplomacy.

Playing games for security: an efficient exact algorithm for solving Bayesian Stackelberg games

Abstract: In a class of games known as Stackelberg games, one agent (the leader) must commit to a strategy that can be observed by the other agent (the follower or adversary) before the adversary chooses its own strategy. We consider Bayesian Stackelberg games, in which the leader is uncertain about the types of adversary it may face. Such games are important in security domains, where, for example, a security agent (leader) must commit to a strategy of patrolling certain areas, and a robber (follower) has a chance to observe this strategy over time before choosing its own strategy of where to attack. This paper presents an efficient exact algorithm for finding the optimal strategy for the leader to commit to in these games. This algorithm, DOBSS, is based on a novel and compact mixed-integer linear programming formulation. Compared to the most efficient algorithm known previously for this problem, DOBSS is not only faster, but also leads to higher quality solutions, and does not suffer from problems of infeasibility that were faced by this previous algorithm. Note that DOBSS is at the heart of the ARMOR system that is currently being tested for security scheduling at the Los Angeles International Airport.

Electrolyte Solutions with a Wide Electrochemical Window for Rechargeable Magnesium Batteries

Abstract: Electrolyte solutions for rechargeable Mg batteries were developed, based on reaction products of phenyl magnesium chloride (PhMgCl) Lewis base and Alcl 3 Lewis acid in ethers. The transmetallation of these ligands forms solutions with Mg x Cl + y and AlCl 4-n Ph n - ions as the major ionic species, as analyzed by multinuclei nuclear magnetic resonance spectroscopy. Tetrahydrofuran (THF) solutions of (PhMgCl) 2 -Alcl 3 exhibit optimal properties: highly reversible Mg deposition (100% cycling efficiency) with low overvoltage: <0.2 V and electrochemical windows wider than 3 V. A specific conductivity of 2-5 X 10 -3 Ω -1 cm -1 could be measured between -10 and 30°C for these solutions, similar to that of standard electrolyte solutions for Li batteries. Mg ions intercalate reversibly with Chevrel phase (Mg x Mo 6 S 8 ) cathodes in these solutions. These systems exhibit high thermal stability. The solutions may enable the use of high voltage, high-capacity Mg insertion materials as cathodes and hence open the door for research and development of high-energy density, rechargeable Mg batteries.

Sonochemical coating of silver nanoparticles on textile fabrics (nylon, polyester and cotton) and their antibacterial activity.

Abstract: Silver nanoparticles were synthesized and deposited on different types of fabrics using ultrasound irradiation. The structure of silver-fabric composites was studied by physico-chemical methods. The mechanism of the strong adhesion of silver nanoparticles to the fibers is discussed. The excellent antibacterial activity of the Ag-fabric composite against Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive) cultures was demonstrated.

Sentiment and Stock Prices: The Case of Aviation Disasters

Abstract: Behavioral economic studies reveal that negative sentiment driven by bad mood and anxiety affects investment decisions and may hence affect asset pricing. In this study we examine the effect of aviation disasters on stock prices. We find evidence of a significant negative event effect with a market average loss of more than $60 billion per aviation disaster, whereas the estimated actual loss is no more than $1 billion. In two days a price reversal occurs. We find the effect to be greater in small and riskier stocks and in firms belonging to less stable industries. This event effect is also accompanied by an increase in the perceived risk: implied volatility increases after aviation disasters without an increase in actual volatility.

Is there intergenerational transmission of trauma? The case of combat veterans' children.

Abstract: This article is a review of the literature on intergenerational transmission of posttraumatic stress disorder (PTSD) from fathers to sons in families of war veterans. The review addresses several questions: (1) Which fathers have a greater tendency to transmit their distress to their offspring? (2) What is transmitted from father to child? (3) How is the distress transmitted and through which mechanisms? And finally, (4) Which children are more vulnerable to the transmission of PTSD distress in the family? Whereas the existing literature deals mainly with fathers' PTSD as a risk for increased emotional and behavior problems among the children, this review also highlights the current paucity of knowledge regarding family members and extrafamilial systems that may contribute to intergenerational transmission of PTSD or to its moderation. Little is also known about resilience and strengths that may mitigate or prevent the risk of intergenerational transmission of trauma.

Mirror, Mirror on the Wall: Culture's Consequences in A Value Test of its Own Design

Abstract: The paper offers a critical reading of Geert Hofstede's (1980) Culture's Consequences using an analytical strategy where the book is mirrored against itself and analyzed in terms of its own proposed value dimensions. “Mirroring” unravels the book's normative viewpoint and political subtext and exposes discursive interests in its research process. Making all this evident in the canonical book's own terms, this paper communicates critical concerns across paradigm boundaries. It indicates the need to reconsider concepts and convictions that predominate cross-cultural research and to adopt norms of reflexivity that transcend existing notions of “cultural relativism.”

Sigma Convergence versus Beta Convergence: Evidence from U.S. County-Level Data

Abstract: In this paper, we outline (i) why σ-convergence may not accompany β-convergence, (ii) discuss evidence of β-convergence in the United States, and (iii) use U.S. county-level data containing over 3,000 cross-sectional observations to demonstrate that σ-convergence cannot be detected at the county level across the United States, or within the large majority of the individual U.S. states considered separately. Indeed, in many cases statistically significant σ-divergence is found.

Finding a better immunization strategy

Abstract: The problem of finding the best strategy to immunize a population or a computer network with a minimal number of immunization doses is of current interest. It has been accepted that the targeted strategies on most central nodes are most efficient for model and real networks. We present a newly developed graph-partitioning strategy which requires 5% to 50% fewer immunization doses compared to the targeted strategy and achieves the same degree of immunization of the network. We explicitly demonstrate the effectiveness of our proposed strategy on several model networks and also on real networks.

A World Survey of Religion and the State

Abstract: 1. Introduction 2. The question of religion's role in politics and society: modernization, secularization, and beyond? 3. Quantifying religion 4. Global GIR from 1990 to 2002 5. Western democracies 6. The former Soviet bloc 7. Asia 8. The Middle East and North Africa 9. Sub-Saharan Africa 10. Latin America 11. Patterns and trends 12. Conclusions.

Comparison of detrending methods for fluctuation analysis

Abstract: We examine several recently suggested methods for the detection of long-range correlations in data series based on similar ideas as the well-established Detrended Fluctuation Analysis (DFA). In particular, we present a detailed comparison between the regular DFA and two recently suggested methods: the Centered Moving Average (CMA) Method and a Modified Detrended Fluctuation Analysis (MDFA). We find that CMA performs the same as DFA in long data with weak trends and is slightly superior to DFA in short data with weak trends. When comparing standard DFA to MDFA we observe that DFA performs slightly better in almost all examples we studied. We also discuss how several types of trends affect different types of DFA. For weak trends in the data, the new methods are comparable with DFA in these respects. However, if the functional form of the trend in data is not a-priori known, DFA remains the method of choice. Only a comparison of DFA results, using different detrending polynomials, yields full recognition of the trends. A comparison with independent methods is recommended for proving long-range correlations.

Climate Networks around the Globe are Significantly Affected by El Niño

Abstract: The temperatures in different zones in the world do not show significant changes due to El Nino except when measured in a restricted area in the Pacific Ocean. We find, in contrast, that the dynamics of a climate network based on the same temperature records in various geographical zones in the world is significantly influenced by El Nino. During El Nino many links of the network are broken, and the number of surviving links comprises a specific and sensitive measure for El Nino events. While during non-El Nino periods these links which represent correlations between temperatures in different sites are more stable, fast fluctuations of the correlations observed during El Nino periods cause the links to break.

Multi-robot perimeter patrol in adversarial settings

Abstract: This paper considers the problem of multi-robot patrol around a closed area with the existence of an adversary attempting to penetrate into the area. In case the adversary knows the patrol scheme of the robots and the robots use a deterministic patrol algorithm, then in many cases it is possible to penetrate with probability 1. Therefore this paper considers a non-deterministic patrol scheme for the robots, such that their movement is characterized by a probability p. This patrol scheme allows reducing the probability of penetration, even under an assumption of a strong opponent that knows the patrol scheme. We offer an optimal polynomial-time algorithm for finding the probability p such that the minimal probability of penetration detection throughout the perimeter is maximized. We describe three robotic motion models, defined by the movement characteristics of the robots. The algorithm described herein is suitable for all three models.

Klotho: a tumor suppressor and a modulator of the IGF-1 and FGF pathways in human breast cancer

Abstract: Klotho is an anti-aging gene, which has been shown to inhibit the insulin and insulin-like growth factor 1 (IGF-1) pathways in mice hepatocytes and myocytes. As IGF-1 and insulin regulate proliferation, survival and metastasis of breast cancer, we studied klotho expression and activities in human breast cancer. Immunohistochemistry analysis of klotho expression in breast tissue arrays revealed high klotho expression in normal breast samples, but very low expression in breast cancer. In cancer samples, high klotho expression was associated with smaller tumor size and reduced KI67 staining. Forced expression of klotho reduced proliferation of MCF-7 and MDA-MB-231 breast cancer cells, whereas klotho silencing in MCF-7 cells, which normally express klotho, enhanced proliferation. Moreover, forced expression of klotho in these cells, or treatment with soluble klotho, inhibited the activation of IGF-1 and insulin pathways, and induced upregulation of the transcription factor CCAAT/enhancer-binding protein β, a breast cancer growth inhibitor that is negatively regulated by the IGF-1-AKT axis. Co-immunoprecipitation revealed an interaction between klotho and the IGF-1 receptor. Klotho is also a known modulator of the fibroblast growth factor (FGF) pathway, a pathway that inhibits proliferation of breast cancer cells. Studies in breast cancer cells revealed increased activation of the FGF pathway by basic FGF following klotho overexpression. Klotho did not affect activation of the epidermal growth factor pathway in breast cancer cells. These data suggest klotho as a potential tumor suppressor and identify it as an inhibitor of the IGF-1 pathway and activator of the FGF pathway in human breast cancer.

Morphological awareness, phonological awareness, and reading in English–Arabic bilingual children

Abstract: The paper reported an exploratory study that tested (a) the relationship between phonological and morphological awareness in English (L1)–Arabic (L2) bilingual children in Canada (N = 43), and (b) the relevance of these skills to word and pseudoword reading accuracy, and to complex word reading fluency. The results showed a significant correlation between phonological awareness in English and in Arabic. However, morphological awareness in the two languages was not correlated. Phonological awareness predicted reading cross-linguistically, but only Arabic morphological awareness predicted word reading in English. Moreover, while both phonological and morphological awareness in English predicted independent unique variance in English word reading, only phonological awareness in Arabic predicted Arabic word reading. Complex-word reading fluency was predicted by morphological awareness within both languages. Similarly, in both languages, phonological awareness was the single factor predicting pseudoword decoding accuracy. The results are discussed in terms of cross-linguistic differences between English and Arabic in orthographic depth and in morphological structure and transparency.

E2F1 regulates autophagy and the transcription of autophagy genes

Abstract: The retinoblastoma pathway is often inactivated in human tumors resulting in deregulated E2F activity that can induce both proliferation and cell death. Although the role of E2F in apoptosis is well characterized, little is known regarding its putative participation in other cell death pathways. We show here that activation of E2F1 upregulates the expression of four autophagy genes-microtubule-associated protein-1 light chain-3 (LC3), autophagy-related gene-1 (ATG1), ATG5 and damage-regulated autophagy modulator (DRAM). E2F1-mediated induction of LC3, ATG1 and DRAM is direct and indeed, endogenous E2F1 can be found bound to regions encompassing the promoters of these genes. Regulation of ATG5 by E2F1 is indirect. Importantly, we demonstrate that E2F1 activation enhances autophagy and conversely, reducing endogenous E2F1 expression inhibits DNA damage-induced autophagy. These studies identify E2F1 as a transcriptional regulator of autophagy, and for the first time establish a role for E2F1 in DNA damage-induced autophagy.

Value Distribution of Meromorphic Functions

Abstract: Characteristics of the behavior of a meromorphic function and the first fundamental theorem Meromorphic functions of finite order The second fundamental theorem Deficient values Asymptotic properties of meromorphic functions and deficiencies Value distribution with respect to the arguments Applications of Riemann surfaces to value distribution On the magnitude of an entire function Notes A survey of some results after 1970 Bibliography References added to the English edition Author index Subject index Notation index.

Efficient protocols for set intersection and pattern matching with security against malicious and covert adversaries

Abstract: In this paper we construct efficient secure protocols for set intersection and pattern matching. Our protocols for securely computing the set intersection functionality are based on secure pseudorandom function evaluations, in contrast to previous protocols that used secure polynomial evaluation. In addition to the above, we also use secure pseudorandom function evaluation in order to achieve secure pattern matching. In this case, we utilize specific properties of the Naor-Reingold pseudorandom function in order to achieve high efficiency. Our results are presented in two adversary models. Our protocol for secure pattern matching and one of our protocols for set intersection achieve security against malicious adversaries under a relaxed definition where one corruption case is simulatable and for the other only privacy (formalized through indistinguishability) is guaranteed. We also present a protocol for set intersection that is fully simulatable in the model of covert adversaries. Loosely speaking, this means that a malicious adversary can cheat, but will then be caught with good probability.

The potential of desferrioxamine-gallium as an anti-Pseudomonas therapeutic agent

Abstract: The opportunistic pathogen Pseudomonas aeruginosa causes infections that are difficult to treat by antibiotic therapy. This bacterium can cause biofilm infections where it shows tolerance to antibiotics. Here we report the novel use of a metallo-complex, desferrioxamine-gallium (DFO-Ga) that targets P. aeruginosa iron metabolism. This complex kills free-living bacteria and blocks biofilm formation. A combination of DFO-Ga and the anti-Pseudomonas antibiotic gentamicin caused massive killing of P. aeruginosa cells in mature biofilms. In a P. aeruginosa rabbit corneal infection, topical administration of DFO-Ga together with gentamicin decreased both infiltrate and final scar size by about 50% compared to topical application of gentamicin alone. The use of DFO-Ga as a Trojan horse delivery system that interferes with iron metabolism shows promise as a treatment for P. aeruginosa infections.

Colloquium: Unusual resonators: Plasmonics, metamaterials, and random media

Abstract: Super-resolution, extraordinary transmission, total absorption, and localization of electromagnetic waves are currently attracting growing attention. These phenomena are related to different physical systems and are usually studied within the context of different, sometimes rather sophisticated, approaches. Remarkably, all these seemingly unrelated phenomena owe their origin to the same underlying physical mechanism, namely, wave interaction with an open resonator. Here we show that it is possible to describe all of these effects in a unified way, mapping each system onto a simple resonator model. Such description provides a thorough understanding of the phenomena, explains all the main features of their complex behavior, and enables one to control the system via the resonator parameters: eigenfrequencies, $Q$ factors, and coupling coefficients.

Surface and deep learning processes in distance education: Synchronous versus asynchronous systems

Abstract: Distance learning is different from regular learning in the classroom. One of the main factors which influence the effectiveness of the learning process is the interaction that exists between the teacher and the student. Our research indicates that different interactions have different effects. There are two methods used for implementing distance learning systems, i.e. synchronous and asynchronous. Our research is based on the model developed by Oliver and McLaughlin. According to this model, there exist five types of teacher-student interactions: social, procedural, expository, explanatory and cognitive. The present study refers to the cognitive interaction and differentiates between surface processes and deep processes. The study presents different variables and their influences on the students' achievements and their satisfaction from learning via a synchronous versus an asynchronous distance learning system. The interaction level between the students and the teacher and among the students was found to be a significant factor in determining the effectiveness of the teaching method. The observations and interviews which we held with the students helped clarify the information that was obtained using the quantitative research tools, and showed that the presence of a teacher-student interaction which accompanies the learning process is very important for all learners. However, students with high-level thinking can overcome the low-level of interactions in asynchronous learning.