Showing papers by "Bar-Ilan University published in 2007"

The Third PASCAL Recognizing Textual Entailment Challenge

Abstract: This paper presents the Third PASCAL Recognising Textual Entailment Challenge (RTE-3), providing an overview of the dataset creating methodology and the submitted systems. In creating this year's dataset, a number of longer texts were introduced to make the challenge more oriented to realistic scenarios. Additionally, a pool of resources was offered so that the participants could share common tools. A pilot task was also set up, aimed at differentiating unknown entailments from identified contradictions and providing justifications for overall system decisions. 26 participants submitted 44 runs, using different approaches and generally presenting new entailment models and achieving higher scores than in the previous challenges.

Parent-infant synchrony and the construction of shared timing; physiological precursors, developmental outcomes, and risk conditions.

Abstract: Synchrony, a construct used across multiple fields to denote the temporal relationship between events, is applied to the study of parent-infant interactions and suggested as a model for intersubjectivity. Three types of timed relationships between the parent and child's affective behavior are assessed: concurrent, sequential, and organized in an ongoing patterned format, and the development of each is charted across the first year. Viewed as a formative experience for the maturation of the social brain, synchrony impacts the development of self-regulation, symbol use, and empathy across childhood and adolescence. Different patterns of synchrony with mother, father, and the family and across cultures describe relationship-specific modes of coordination. The capacity to engage in temporally-matched interactions is based on physiological mechanisms, in particular oscillator systems, such as the biological clock and cardiac pacemaker, and attachment-related hormones, such as oxytocin. Specific patterns of synchrony are described in a range of child-, parent- and context-related risk conditions, pointing to its ecological relevance and usefulness for the study of developmental psychopathology. A perspective that underscores the organization of discrete relational behaviors into emergent patterns and considers time a central parameter of emotion and communication systems may be useful to the study of interpersonal intimacy and its potential for personal transformation across the lifespan.

A model of Internet topology using k-shell decomposition.

Abstract: We study a map of the Internet (at the autonomous systems level), by introducing and using the method of k-shell decomposition and the methods of percolation theory and fractal geometry, to find a model for the structure of the Internet. In particular, our analysis uses information on the connectivity of the network shells to separate, in a unique (no parameters) way, the Internet into three subcomponents: (i) a nucleus that is a small (≈100 nodes), very well connected globally distributed subgraph; (ii) a fractal subcomponent that is able to connect the bulk of the Internet without congesting the nucleus, with self-similar properties and critical exponents predicted from percolation theory; and (iii) dendrite-like structures, usually isolated nodes that are connected to the rest of the network through the nucleus only. We show that our method of decomposition is robust and provides insight into the underlying structure of the Internet and its functional consequences. Our approach of decomposing the network is general and also useful when studying other complex networks.

Motivation to Lead, Motivation to Follow: The Role of the Self-Regulatory Focus in Leadership Processes

Abstract: In this paper we integrate recent theories of motivation and leadership. Drawing on the self-regulatory focus theory and on self-concept based theories of leadership, we develop a conceptual framework proposing that leaders' chronic self-regulatory focus (promotion versus prevention), in conjunction with their values, influences their motivation to lead and, subsequently, their leadership behavior. We further suggest that leaders may influence the motivational self-regulatory foci of their followers, which will mediate different follower outcomes at the individual and group level.

Evidence for a Neuroendocrinological Foundation of Human Affiliation: Plasma Oxytocin Levels Across Pregnancy and the Postpartum Period Predict Mother-Infant Bonding

Abstract: Although research on the neurobiological foundation of social affiliation has implicated the neuropeptide oxytocin in processes of maternal bonding in mammals, there is little evidence to support such links in humans. Plasma oxytocin and cortisol of 62 pregnant women were sampled during the first trimester, last trimester, and first postpartum month. Oxytocin was assayed using enzyme immunoassay, and free cortisol was calculated. After the infants were born, their interactions with their mothers were observed, and the mothers were interviewed regarding their infant-related thoughts and behaviors. Oxytocin was stable across time, and oxytocin levels at early pregnancy and the postpartum period were related to a clearly defined set of maternal bonding behaviors, including gaze, vocalizations, positive affect, and affectionate touch; to attachment-related thoughts; and to frequent checking of the infant. Across pregnancy and the postpartum period, oxytocin may play a role in the emergence of behaviors and mental representations typical of bonding in the human mother.

Boosting Attachment Security to Promote Mental Health, Prosocial Values, and Inter-Group Tolerance

Abstract: In this article, we conceptualize the sense of attachment security as an inner resource and present theory and research on the broaden and build cycle of attachment security generated by the actual or symbolic encounter with external or internalized loving and caring relationship partners. We also propose that the body of research stimulated by attachment theory offers productive hints about interventions that might increase positive experiences and prosocial behavior by bolstering a person's sense of security. On this basis, we review recent experimental studies showing how interventions designed to increase attachment security have beneficial effects on mental health, prosocial behavior, and intergroup relations, and discuss unaddressed issues concerning the mechanism underlying the beneficial effects of these interventions, the temporal course of these effects, and their interaction with countervailing forces.

In vivo dynamics of RNA polymerase II transcription

Abstract: We imaged transcription in living cells using a locus-specific reporter system, which allowed precise, single-cell kinetic measurements of promoter binding, initiation and elongation. Photobleaching of fluorescent RNA polymerase II revealed several kinetically distinct populations of the enzyme interacting with a specific gene. Photobleaching and photoactivation of fluorescent MS2 proteins used to label nascent messenger RNAs provided sensitive elongation measurements. A mechanistic kinetic model that fits our data was validated using specific inhibitors. Polymerases elongated at 4.3 kilobases min−1, much faster than previously documented, and entered a paused state for unexpectedly long times. Transcription onset was inefficient, with only 1% of polymerase-gene interactions leading to completion of an mRNA. Our systems approach, quantifying both polymerase and mRNA kinetics on a defined DNA template in vivo with high temporal resolution, opens new avenues for studying regulation of transcriptional processes in vivo.

The Role of Perceived Organizational Performance in Organizational Identification, Adjustment and Job Performance

Abstract: Favourable organizational status and prestige has a substantial role in shaping constituents' attitudes and actions. The status and prestige of an organization is often a reflection of its achievements or performance. In the present study, we investigate the role of organizational performance or achievement (as assessed by organizational members) in evoking employees' identification, adjustment, and job performance. The results of this study indicate that two forms of organizational performance (labelled as perceived social responsibility and development and perceived market and financial performance) are associated with organizational identification. However, when compared to perceived market and financial performance, perceived social responsibility and development had a larger effect on organizational identification, which in turn resulted in enhanced employees' work outcomes – adjustment and job performance.

An Efficient Protocol for Secure Two-Party Computation in the Presence of Malicious Adversaries

Abstract: Check if we can apply Woodruff's method to our protocol. We show an efficient secure two-party protocol, based on Yao's construction, which provides security against malicious adversaries. Yao's original protocol is only secure in the presence of semi-honest adversaries. Security against malicious adversaries can be obtained by applying the compiler of Goldreich, Micali and Wigderson (the "GMW compiler"). However, this approach does not seem to be very practical as it requires using generic zero-knowledge proofs. Our construction is based on applying cut-and-choose techniques to the original circuit and inputs. Security is proved according to the ideal/real simulation paradigm, and the proof is in the standard model (with no random oracle model or common reference string assumptions). The resulting protocol is computationally efficient: the only usage of asymmetric cryptography is for running O(1) oblivious transfers for each input bit (or for each bit of a statistical security parameter, whichever is larger). Our protocol combines techniques from folklore (like cut-and-choose) along with new techniques for efficiently proving consistency of inputs. We remark that a naive implementation of the cut-and-choose technique with Yao's protocol does notyield a secure protocol. This is the first paper to show how to properly implement these techniques, and to provide a full proof of security. Our protocol can also be interpreted as a constant-round black-box reduction of secure two-party computation to oblivious transfer and perfectly-hiding commitments, or a black-box reduction of secure two-party computation to oblivious transfer alone, with a number of rounds which is linear in a statistical security parameter. These two reductions are comparable to Kilian's reduction, which uses OT alone but incurs a number of rounds which is linear in the depth of the circuit [18].

Parent–Infant Synchrony Biological Foundations and Developmental Outcomes

Abstract: Synchrony—a construct used across multiple fields to denote the temporal relationship between events—has been applied to the study of mother–infant interaction and is suggested here as a framework for the study of interpersonal relationships. Defined as the temporal coordination of micro-level social behavior, parent–infant synchrony is charted in its development across infancy from the initial consolidation of biological rhythms during pregnancy to the emergence of symbolic exchange between parent and child. Synchrony is shown to depend on physiological mechanisms supporting bond formation in mammals—particularly physiological oscillators and neuroendocrine systems such as those involving the hormone oxytocin. Developmental outcomes of the synchrony experience are observed in the domains of self-regulation, symbol use, and the capacity for empathy across childhood and adolescence. Specific disruptions to the parameters of synchrony that may be observed in various pathological conditions, such as prematur...

The influence of leaders' and other referents' normative expectations on individual involvement in creative work

Abstract: We examined how the perceived expectations of the leader, customers, and family influence individuals' creative involvement at work. The perceived expectations of all three of these reference groups were positively associated with employee's self-expectations for creativity. These self-expectations for creativity, in turn, were associated with creative involvement at work. This latter effect was stronger among participants who reported higher self-efficacy for creativity. Implications for how leaders support followers' creative behavior are discussed.

Mitochondrial function in vivo evaluated by NADH fluorescence: from animal models to human studies.

Abstract: Normal mitochondrial function is a critical factor in maintaining cellular homeostasis in various organs of the body. Due to the involvement of mitochondrial dysfunction in many pathological states, the real-time in vivo monitoring of the mitochondrial metabolic state is crucially important. This type of monitoring in animal models as well as in patients provides real-time data that can help interpret experimental results or optimize patient treatment. The goals of the present review are the following: 1) to provide an historical overview of NADH fluorescence monitoring and its physiological significance; 2) to present the solid scientific ground underlying NADH fluorescence measurements based on published materials; 3) to provide the reader with basic information on the methodologies used in the past and the current state of the art fluorometers; and 4) to clarify the various factors affecting monitored signals, including artifacts. The large numbers of publications by different groups testify to the valuable information gathered in various experimental conditions. The monitoring of NADH levels in the tissue provides the most important information on the metabolic state of the mitochondria in terms of energy production and intracellular oxygen levels. Although NADH signals are not calibrated in absolute units, their trend monitoring is important for the interpretation of physiological or pathological situations. To understand tissue function better, the multiparametric approach has been developed where NADH serves as the key parameter. The development of new light sources in UV and visible spectra has led to the development of small compact units applicable in clinical conditions for better diagnosis of patients.

Scleractinian coral species survive and recover from decalcification.

Abstract: Anthropogenic-driven accumulation of carbon dioxide in the atmosphere and projected ocean acidification have raised concerns regarding the eventual impact on coral reefs. This study demonstrates that skeleton-producing corals grown in acidified experimental conditions are able to sustain basic life functions, including reproductive ability, in a sea anemone‐like form and will resume skeleton building when reintroduced to normal modern marine conditions. These results support the existence of physiological refugia, allowing corals to alternate between nonfossilizing soft-body ecophenotypes and fossilizing skeletal forms in response to changes in ocean chemistry. This refugia, however, does not undermine the threats to reef ecosystems in a high carbon dioxide world.

How to calculate the fractal dimension of a complex network: the box covering algorithm

Abstract: Covering a network with the minimum possible number of boxes can reveal interesting features for the network structure, especially in terms of self-similar or fractal characteristics. Considerable attention has been recently devoted to this problem, with the finding that many real networks are self-similar fractals. Here we present, compare and study in detail a number of algorithms that we have used in previous papers towards this goal. We show that this problem can be mapped to the well-known graph colouring problem and then we simply can apply well-established algorithms. This seems to be the most efficient method, but we also present two other algorithms based on burning which provide a number of other benefits. We argue that the algorithms presented provide a solution close to optimal and that another algorithm that can significantly improve this result in an efficient way does not exist. We offer to anyone that finds such a method to cover his/her expenses for a one-week trip to our lab in New York (details in http://jamlab.org).

Maternal postpartum behavior and the emergence of infant-mother and infant-father synchrony in preterm and full-term infants: the role of neonatal vagal tone.

Abstract: Relations between maternal postpartum behavior and the emergence of parent-infant relatedness as a function of infant autonomic maturity were examined in 56 premature infants (birthweight = 1000-1500 g) and 52 full-term infants. Maternal behavior, mother depressive symptoms, and infant cardiac vagal tone were assessed in the neonatal period. Infant-mother and infant-father synchrony, maternal and paternal affectionate touch, and the home environment were observed at 3 months. Premature birth was associated with higher maternal depression, less maternal behaviors, decreased infant alertness, and lower coordination of maternal behavior with infant alertness in the neonatal period. At 3 months, interactions between premature infants with their mothers and fathers were less synchronous. Interaction effects of premature birth and autonomic maturity indicated that preterm infants with low vagal tone received the lowest amounts of maternal behavior in the postpartum and the least maternal touch at 3 months. Infant-mother and infant-father synchrony were each predicted by cardiac vagal tone and maternal postpartum behavior in both the preterm and full-term groups. Among preterm infants, additional predictors of parent-infant synchrony were maternal depression (mother only) and the home environment (mother and father). Findings are consistent with evolutionary perspectives on the higher susceptibility of dysregulated infants to rearing contexts and underscore the compensatory mechanisms required for social-emotional growth under risk conditions for parent-infant bonding.

Novel Insights into Wound Healing Sequence of Events

Abstract: Effective wound healing leads to restoration of tissue integrity and occurs through a highly organized multistage process involving various cell types. Currently, methods for wound healing assessment lack a structured system for analysis of quantitative parameters. We have established a unique quantitative assessment strategy of wound healing stages based on histological criteria. Distinctive immunohistochemical parameters including re-epithelialization, epidermal differentiation, cell migration, proliferation, inflammatory response as well as dermal closure, matrix distribution, and skin remodelling were identified and followed during the timeline of wound healing progression. Assessment was based on various defined characteristics and each stage-specific parameter was independently quantified for complete wound closure. This analysis allowed a follow-up of wound healing dynamics and identified the contribution of critical and specific parameters to wound healing physiology and pathology. In this review we demonstrate our assessment strategy of crucial wound healing events and introduce a unique quantification system for each of the processes involved in wound repair. We believe that our unique method can be utilized as a diagnostic platform for standardizing assessment of wound healing progression as well as a screening tool for potential therapies.

Self-Selection Patterns in Mexico-U.S. Migration: The Role of Migration Networks

Abstract: The authors examine the role of migration networks in determining self-selection patterns of Mexico-U.S. migration. They first present a simple theoretical framework showing how such networks impact on migration incentives at different education levels and, consequently, how they are likely to affect the expected skill composition of migration. Using survey data from Mexico, the authors then show that the probability of migration is increasing with education in communities with low migrant networks, but decreasing with education in communities with high migrant networks. This is consistent with positive self-selection of migrants being driven by high migration costs, and with negative self-selection of migrants being driven by lower returns to education in the U.S. than in Mexico.

Leaders as attachment figures: leaders' attachment orientations predict leadership-related mental representations and followers' performance and mental health

Abstract: In 3 studies, the authors examined the contribution of leaders' attachment styles to their leadership motives and beliefs and to followers' outcomes. In Study 1, participants completed measures of attachment orientation, leadership motives, self-representations, and leadership style. Studies 2 and 3 were conducted within Israeli military units either during a leadership workshop or during intensive combat training. Israeli military officers and their soldiers (followers) reported on their attachment styles, and the soldiers reported on the officers' leadership qualities and on the soldiers' own performance and mental health. Leaders' attachment anxiety was associated with more self-serving leadership motives and with poorer leadership qualities in task-oriented situations. Leaders' attachment anxiety also predicted followers' poorer instrumental functioning. Leaders' attachment-related avoidance was negatively associated with prosocial motives to lead, with the failure to act as a security provider, and with followers' poorer socioemotional functioning and poorer long-range mental health. Results are discussed with respect to the value of attachment theory for the study of leadership.