Showing papers by "University of Haifa published in 2003"

Linking bees and flowers: how do floral communities structure pollinator communities?

Abstract: Pollinators provide essential ecosystem services, and declines in some pollinator communities around the world have been reported. Understanding the fundamental components defining these communities is essential if conservation and restoration are to be successful. We examined the structure of plant-pollinator communities in a dynamic Mediterranean landscape, comprising a mosaic of post-fire regenerating habitats, and which is a recognized global hotspot for bee diversity. Each community was characterized by a highly skewed species abundance distribution, with a few dominant and many rare bee species, and was consistent with a log series model indicating that a few environmental factors govern the community. Floral community composition, the quantity and quality of forage resources present, and the geographic locality organized bee communities at various levels: (1) The overall structure of the bee community (116 species), as revealed through ordination, was dependent upon nectar resource diversity (defined as the variety of nectar volume-concentration combinations available), the ratio of pollen to nectar energy, floral diversity, floral abundance, and post-fire age. (2) Bee diversity, measured as species richness, was closely linked to floral diversity (especially of annuals), nectar resource diversity, and post-fire age of the habitat. (3) The abundance of the most common species was primarily related to post-fire age, grazing intensity, and nesting substrate availability. Ordination models based on age-characteristic post-fire floral community structure explained 39-50% of overall variation observed in bee community structure. Cluster analysis showed that all the communities shared a high degree of similarity in their species composition (27-59%); however, the geographical location of sites also contributed a smaller but significant component to bee community structure. We conclude that floral resources act in specific and previously unexplored ways to modulate the diversity of the local geographic species pool, with specific disturbance factors, superimposed upon these patterns, mainly affecting the dominant species.

Organizational Responses to Customer Complaints: What Works and What Doesn’t:

Abstract: The purpose of this article is to summarize the current research in the field of complaint handling, specifically to focus on how the organizational response to a customer complaint affects the postcomplaint customer behavior. A model framework is presented that divides these organizational responses into six separate dimensions (timeliness, facilitation, redress, apology, credibility, and attentiveness) and takes an in-depth look at each dimension in turn. Major questions and conclusions are presented for each dimension, which attempt to clarify what is really known or not known about the effect of that dimension on postcomplaint customer behavior. Special topics of future areas of research are discussed and a revised framework is presented to facilitate future research.

Characterization of Empathy Deficits following Prefrontal Brain Damage: The Role of the Right Ventromedial Prefrontal Cortex

Abstract: Impaired empathic response has been described in patients following brain injury, suggesting that empathy may be a fundamental aspect of the social behavior disturbed by brain damage. However, the neuroanatomical basis of impaired empathy has not been studied in detail. The empathic response of patients with localized lesions in the prefrontal cortex (n = 25) was compared to responses of patients with posterior (n = 17) and healthy control subjects (n = 19). To examine the cognitive processes that underlie the empathic ability, the relationships between empathy scores and the performance on tasks that assess processes of cognitive flexibility, affect recognition, and theory of mind (TOM) were also examined. Patients with prefrontal lesions, particularly when their damage included the ventromedial prefrontal cortex, were significantly impaired in empathy as compared to patients with posterior lesions and healthy controls. However, among patients with posterior lesions, those with damage to the right hemisphere were impaired, whereas those with left posterior lesions displayed empathy levels similar to healthy controls. Seven of nine patients with the most profound empathy deficit had a right ventromedial lesion. A differential pattern regarding the relationships between empathy and cognitive performance was also found: Whereas among patients with dorsolateral prefrontal damage empathy was related to cognitive flexibility but not to TOM and affect recognition, empathy scores in patients with ventromedial lesions were related to TOM but not to cognitive flexibility. Our findings suggest that prefrontal structures play an important part in a network mediating the empathic response and specifically that the right ventromedial cortex has a unique role in integrating cognition and affect to produce the empathic response.

Do People Watch what they Do Not Trust? Exploring the Association between News Media Skepticism and Exposure

Abstract: This article explores a possible association between skepticism toward the media and audience exposure patterns. Hypotheses predicting a relationship between media skepticism and news media consumption are tested on four large sample data sets. Findings show that media skepticism is negatively associated with mainstream news exposure but positively associated with nonmainstream news exposure.

Tail Conditional Expectations for Elliptical Distributions

Abstract: Significant changes in the insurance and financial markets are giving increasing attention to the need for developing a standard framework for risk measurement. Recently, there has been growing interest among insurance and investment experts to focus on the use of a tail conditional expectation because it shares properties that are considered desirable and applicable in a variety of situations. In particular, it satisfies requirements of a “coherent” risk measure in the spirit developed by Artzner et al. (1999). This paper derives explicit formulas for computing tail conditional expectations for elliptical distributions, a family of symmetric distributions that includes the more familiar normal and student-t distributions. The authors extend this investigation to multivariate elliptical distributions allowing them to model combinations of correlated risks. They are able to exploit properties of these distributions, naturally permitting them to decompose the conditional expectation, and allocate t...

Multiple shifts in the representation of a motor sequence during the acquisition of skilled performance

Abstract: When do learning-related changes in performance occur? Here we show that the knowledge of a sequence of movements evolves through several distinctive phases that depend on two critical factors: the amount of practice as well as the passage of time. Our results show the following. (i) Within a given session, large performance gains constituted a signature for motor novelty. Such gains occurred only for newly introduced conditions irrespective of the absolute level of performance. (ii) A single training session resulted in both immediate but also time-dependent, latent learning hours after the termination of practice. Time in sleep determined the time of expression of these delayed gains. Moreover, the delayed gains were sequence-specific, indicating a qualitative change in the representation of the task within 24 h posttraining. (iii) Prolonged training resulted in additional between-session gains that, unlike the effects of a single training session, were confined to the trained hand. Thus, the effects of multisession training were qualitatively different than the immediate and time-dependent effects of a single session. Altogether, our results indicate multiple time-dependent shifts in the representation of motor experience during the acquisition of skilled performance.

Impaired interleukin-1 signaling is associated with deficits in hippocampal memory processes and neural plasticity.

Abstract: The cytokine interleukin-1 (IL-1) is produced by peripheral immune cells as well as glia and neurons within the brain; it plays a major role in immune to brain communication and in modulation of neural, neuroendocrine, and behavioral systems during illness. Although previous studies demonstrated that excess levels of IL-1 impaired memory processes and neural plasticity, it has been suggested that physiological levels of IL-1 are involved in hippocampal-dependent memory and long-term potentiation (LTP). To examine this hypothesis, we studied IL-1 receptor type I knockout (IL-1rKO) mice in several paradigms of memory function and hippocampal plasticity. In the spatial version of the water maze test, IL-1rKO mice displayed significantly longer latency to reach a hidden platform, compared with wild-type controls. Furthermore, IL-1rKO exhibited diminished contextual fear conditioning. In contrast, IL-1rKO mice were similar to control animals in hippocampal-independent memory tasks; i.e., their performance in the visually guided task of the water maze and the auditory-cued fear conditioning was normal. Electrophysiologically, anesthetized IL-1rKO mice exhibited enhanced paired-pulse inhibition in response to perforant path stimulation and no LTP in the dentate gyrus. In vitro, decreased paired-pulse responses, as well as a complete absence of LTP, were observed in the CA1 region of hippocampal slices taken from IL-1rKO mice compared with WT controls. These results suggest that IL-1 contributes to the regulation of memory processes as well as short- and long-term plasticity within the hippocampus. These findings have important implications to several conditions in humans, which are associated with long-term defects in IL-1 signaling, such as mutations in the IL-1 receptor accessory protein-like gene, which are involved in a frequent form of X-linked mental retardation.

Domestication quantitative trait loci in Triticum dicoccoides, the progenitor of wheat.

Abstract: Wild emmer wheat, Triticum dicoccoides, is the progenitor of modern tetraploid and hexaploid cultivated wheats. Our objective was to map domestication-related quantitative trait loci (QTL) in T. dicoccoides. The studied traits include brittle rachis, heading date, plant height, grain size, yield, and yield components. Our mapping population was derived from a cross between T. dicoccoides and Triticum durum. Approximately 70 domestication QTL effects were detected, nonrandomly distributed among and along chromosomes. Seven domestication syndrome factors were proposed, each affecting 5-11 traits. We showed: (i) clustering and strong effects of some QTLs; (ii) remarkable genomic association of strong domestication-related QTLs with gene-rich regions; and (iii) unexpected predominance of QTL effects in the A genome. The A genome of wheat may have played a more important role than the B genome during domestication evolution. The cryptic beneficial alleles at specific QTLs derived from T. dicoccoides may contribute to wheat and cereal improvement.

The Family in Israel: Between Tradition and Modernity

Abstract: This article provides a review of family patterns and lifestyles within Israeli society consisting of trends in marriage, divorce and fertility, dating, mate selection, marital relationships, and marital dissolution Additional topics consist of parenting and the place and role of children in families, elderly and their families, gender issues, division of labor, power in families, and the impact of stress on Israeli familiesMajor trends are presented and analyzed by adopting a hybrid comparative perspective: a vertical perspective, which examines changes in family patterns over the past five decades, and a horizontal perspective, which examines different family patterns among various socioethnic groups This analysis indicates that the family is being pulled in opposite directions by two main forces: one that prods the family toward greater modernization and Westernalization, while the other acts to strengthen traditional values Despite some convergence among different socioethnic groups, mark

Exposure to Acute Stress Blocks the Induction of Long-Term Potentiation of the Amygdala–Prefrontal Cortex Pathway In Vivo

Abstract: In recent years, attention has been given to the interaction between the emotional state of the animal and its ability to learn and remember. Studies into the neural mechanisms underlying these interactions have focused on stress-induced synaptic plasticity impairments in the hippocampus. However, other brain areas, including the amygdala and the prefrontal cortex (PFC), have been implicated in relation to stress-mediated effects on memory. The present study examined whether stress, which impairs hippocampal long-term potentiation (LTP), also affects LTP of the basolateral amygdala (BLA)-PFC pathway in vivo. We first confirmed that the stress protocol we used, i.e., the elevated platform stress, was effective in blocking LTP in the CA1 area of the hippocampus. We then characterized activity and established the ability to induce LTP at the BLA-PFC pathway. Finally, we examined the effects of an exposure to the elevated platform stress on the ability to induce LTP in this pathway. The results indicate that, at the same time when LTP is blocked in the hippocampus, it is also inhibited in the BLA-medial PFC pathway. These results call for a shift from a focused attention on the effects of stress on plasticity in the hippocampus to a system level approach that emphasizes the possible modification of interactions between relevant brain areas after an exposure to a stressful experience.

Biodiversity of 52 chicken populations assessed by microsatellite typing of DNA pools

Abstract: In a project on the biodiversity of chickens funded by the European Commission (EC), eight laboratories collaborated to assess the genetic variation within and between 52 populations from a wide range of chicken types. Twenty-two di-nucleotide microsatellite markers were used to genotype DNA pools of 50 birds from each population. The polymorphism measures for the average, the least polymorphic population (inbred C line) and the most polymorphic population (Gallus gallus spadiceus) were, respectively, as follows: number of alleles per locus, per population: 3.5, 1.3 and 5.2; average gene diversity across markers: 0.47, 0.05 and 0.64; and proportion of polymorphic markers: 0.91, 0.25 and 1.0. These were in good agreement with the breeding history of the populations. For instance, unselected populations were found to be more polymorphic than selected breeds such as layers. Thus DNA pools are effective in the preliminary assessment of genetic variation of populations and markers. Mean genetic distance indicates the extent to which a given population shares its genetic diversity with that of the whole tested gene pool and is a useful criterion for conservation of diversity. The distribution of population-specific (private) alleles and the amount of genetic variation shared among populations supports the hypothesis that the red jungle fowl is the main progenitor of the domesticated chicken.

Are children of Holocaust survivors less well-adapted? A meta-analytic investigation of secondary traumatization

Abstract: H. Keilson (1979) coined the term "sequential traumatization" for the accumulation of traumatic stresses confronting the Holocaust survivors before, during, and after the war. A central question is whether survivors were able to raise their children without transmitting the traumas of their past. Through a series of meta-analyses on 32 samples involving 4,418 participants, we tested the hypothesis of secondary traumatization in Holocaust survivor families. In the set of adequately designed nonclinical studies, no evidence for the influence of the parents' traumatic Holocaust experiences on their children was found. Secondary traumatization emerged only in studies on clinical participants, who were stressed for other reasons. A stress-diathesis model is used to interpret the absence of secondary traumatization in nonclinical offspring of Holocaust survivors.

Happy Adolescents: The Link Between Subjective Well-Being, Internal Resources, and Parental Factors

Abstract: The research investigates the associations of personal and parental factors with subjective well-being (SWB) in adolescents on the basis of 2 studies. The first included 97 university students and 185 adolescents who completed questionnaires measuring perceived mastery, dispositional optimism, and affect used as a measure of SWB. Correlations and hierarchical regression analyses showed mastery and optimism to be negatively associated with negative affect (NA) and positively associated with positive affect (PA). Demographic variables did not relate to PA and NA except for gender, with female adolescents showing higher levels of NA than males. The second study included 121 adolescents and their parents who completed questionnaires measuring mastery, optimism, SWB indicators, and assessments by the adolescents of their relationships with their parents. The associations of the adolescents' mastery and optimism with SWB measures were positive and were similar to those found in the first study. Positive correlations were found between the adolescents' and their parents' SWB (especially with their father's), but no significant associations were observed between adolescents' and parents' mastery and optimism. However, adolescents' mastery and optimism were related to positive relationships with parents. The results highlight the importance of mastery, optimism, and positive adolescent–parent relationships in contributing to the well-being ofadolescents.

Postcesarean Section Pain Prediction by Preoperative Experimental Pain Assessment

Abstract: BACKGROUND Postcesarean section pain is a common cause of acute pain in obstetrics, yet pain relief and patient satisfaction are still inadequate in many cases. The present study was conducted to determine whether preoperative assessment of experimental pain perception by quantitative sensory tests could predict the level of postcesarean section pain. METHODS Fifty-eight women who were scheduled for elective cesarean section were enrolled in the study. Heat pain threshold and magnitude estimation of suprathreshold pain stimuli at 44 degrees-48 degrees C were assessed for both algosity (the sensory dimension of pain intensity) and unpleasantness 1 or 2 days before surgery. The day after the operation, the women reported the level of pain at the surgical wound on a visual analog scale at rest and during activity. Regression analysis was performed to evaluate the usefulness of preoperative scores in predicting postcesarean section pain. RESULTS Postoperative visual analog scale scores at rest and during activity significantly correlated with preoperative suprathreshold pain scores at 44 degrees-48 degrees C (r = 0.31-0.58 for algosity and r = 0.33-0.74 for unpleasantness). The stimulus of 48 degrees C was found to be the best predictor of postoperative pain for both conditions (r = 0.434-0.527; P < 0.01). In contrast to suprathreshold pain stimuli, pain threshold was not correlated with postoperative pain. CONCLUSIONS The results show that a simple and quick preoperative test is useful in identifying those women who will experience greater pain after a cesarean section. This test may be suggested for caregivers to tailor the postoperative treatment to specific patient needs and to improve postoperative outcome and patient satisfaction.

Dust Storms in the Middle East: Sources of Origin and Their Temporal Characteristics

Abstract: The spatial and temporal characteristics of dust storms in the Middle East were studied by an analysis of the visibility reduction in that region. Eight ‘three-hours’ mean values for each month for a period of 21 years (1973–1993) were used. Data were subjected to cluster analysis of their temporal behaviour. Four main regions were identified and mapped. Stations within each cluster (region) have a similar temporal behaviour different from the behaviour of stations out of that cluster. Sudan, Iraq, Saudi Arabia and the Persian Gulf, are the regions that reported the greatest occurrence of dust storms. Dust storms in Iran, north-eastern Iraq and Syria, the Persian Gulf and southern Arabian Peninsula are more frequent in summer. In western Iraq and Syria, Jordan, Lebanon, northern Israel, northern Arabian Peninsula and southern Egypt they occur mainly in the spring, while in southern Israel and in the Mediterranean parts of northern Egypt, in winter and spring.

Origin and evolution of circadian clock genes in prokaryotes

Abstract: Regulation of physiological functions with approximate daily periodicity, or circadian rhythms, is a characteristic feature of eukaryotes. Until recently, cyanobacteria were the only prokaryotes reported to possess circadian rhythmicity. It is controlled by a cluster of three genes: kaiA, kaiB, and kaiC. Using sequence data of ≈70 complete prokaryotic genomes from the various public depositories, we show here that the kai genes and their homologs have quite a different evolutionary history and occur in Archaea and Proteobacteria as well. Among the three genes, kaiC is evolutionarily the oldest, and kaiA is the youngest and likely evolved only in cyanobacteria. Our data suggest that the prokaryotic circadian pacemakers have evolved in parallel with the geological history of the earth, and that natural selection, multiple lateral transfers, and gene duplications and losses have been the major factors shaping their evolution.

Back to basics: applying a parenting perspective to transformational leadership

Abstract: Developmental processes lie at the heart of the relationship between transformational leaders and followers. First, three major domains in which developmental outcomes have been mostly discussed, namely motivation, empowerment, and morality, are highlighted, expanded, and discussed. Next the analogy between transformational leaders and ‘‘good parents’’ is employed to explore the underlying developmental processes. Specifically, conceptualizations, notions, and findings are borrowed from the vast literature on parenting to help us understand these processes. Several major arguments and propositions, which can be tested empirically, are formulated by means of this analogy. These propositions and their conceptualization can broaden our perspective about the processes that underlie many of the outcome variables so frequently investigated and discussed in the leadership literature, and offer a major opportunity to probe the currently less explored developmental and dynamic aspects of leadership.

Coalition formation with uncertain heterogeneous information

Abstract: Coalition formation methods allow agents to join together and are thus necessary in cases where tasks can only be performed cooperatively by groups. This is the case in the Request For Proposal (RFP) domain, where some requester business agent issues an RFP - a complex task comprised of sub-tasks - and several service provider agents need to join together to address this RFP. In such environments the value of the RFP may be common knowledge, however the costs that an agent incurs for performing a specific sub-task are unknown to other agents. Additionally, time for addressing RFPs is limited. These constraints make it hard to apply traditional coalition formation mechanisms, since those assume complete information, and time constraints are of lesser significance there.To address this problem, we have developed a protocol that enables agents to negotiate and form coalitions, and provide them with simple heuristics for choosing coalition partners. The protocol and the heuristics allow the agents to form coalitions in the face of time constraints and incomplete information. The overall payoff of agents using our heuristics is very close to an experimentally measured optimal value, as our extensive experimental evaluation shows.

Product and Process Evaluation of Handwriting Difficulties

Abstract: Handwriting is a complex human activity that entails an intricate blend of cognitive, kinesthetic, and perceptual-motor components. Children are expected to acquire a level of handwriting proficiency that enables them to make skillful use of handwriting as a tool to carry out their work at school. Poor handwriters have difficulty developing their writing skills and, as a result, often suffer in their educational and emotional development. This article highlights the importance of handwriting and reviews the development of methods used to evaluate handwriting difficulties. Included also is a discussion of methodological aspects of current handwriting evaluations and a presentation of research on the use of a computerized system that may be helpful in better understanding the handwriting process of poor writers. The article concludes by outlining future directions in handwriting evaluation that combine the assessment of the handwriting product with computerized analysis of the handwriting process.

Workaholism: Its Definition and Nature

Abstract: The term ‘workaholism’ is widely used, but there is little consensus about its meaning, beyond that of its core element: a substantial investment in work. Following Snir and Zohar, workaholism was first defined in the present study as the individual’s steady and considerable allocation of time to work-related activities and thoughts, which does not derive from external necessities. Subsequently, it was measured as time invested in work, while controlling the financial needs for this investment. The relation between workaholism and possible attitudinal (meaning of work indices), demographic (gender, marital status), and situational (occupation type, employment sector) variables was examined through two representative samples of the Israeli labor force. The following predictor variables were significantly related to workaholism: work centrality, economic orientation, occupation type, employment sector and gender. From those variables, gender was found to be the strongest predictor - that is, men, in compari...

Word Recognition and Basic Cognitive Processes among Reading-Disabled and Normal Readers in Arabic.

Abstract: This study investigated word identification inArabic and basic cognitive processes inreading-disabled (RD) and normal readers of thesame chronological age, and in younger normalreaders at the same reading level. The studyfocused on the word identification processes ofphonological decoding and orthographicprocessing and the cognitive processes ofsyntactic and morphological awareness, workingmemory, and visual processing. RD children werecompared with normal readers on a battery oftests developed in Arabic on the basis of thoseavailable in English and Hebrew. The presentresults revealed deficiencies among the RD childrenin phonological decoding, in contrast torelative strengths in orthographic processing. These data were consistent with English-languagefindings. The analysis of basiccognitive processes indicated significantdeficiencies in morphology, working memory, andsyntactic and visual processing, with the mostsevere deficiencies observed for phonologicalawareness. The results are discussed in lightof international RD findings and the nature ofArabic orthography.

Precise mapping of a locus affecting grain protein content in durum wheat

Abstract: Grain protein content (GPC) is an important factor in pasta and breadmaking quality, and in human nutrition. It is also an important trait for wheat growers because premium prices are frequently paid for wheat with high GPC. A promising source for alleles to increase GPC was detected on chromosome 6B of Triticum turgidum var. dicoccoides accession FA-15-3 (DIC). Two previous quantitative trait locus (QTL) studies found that the positive effect of DIC-6B was associated to a single locus located between the centromere and the Nor-B2 locus on the short arm of chromosome 6B. Microsatellite markers Xgwm508 and Xgwm193 flanking the QTL region were used in this study to develop 20 new homozygous recombinant substitution lines (RSLs) with crossovers between these markers. These 20 RSLs, plus nine RSLs developed in previous studies were characterized with four new RFLP markers located within this chromosome segment. Grain protein content was determined in three field experiments organized as randomized complete block designs with ten replications each. The QTL peaks for protein content were located in the central region of a 2.7-cM interval between RFLP markers Xcdo365 and Xucw67 in the three experiments. Statistical analyses showed that almost all lines could be classified unequivocally within low- and high- protein groups, facilitating the mapping of this trait as a single Mendelian locus designated Gpc-6B1. The Gpc-6B1 locus was mapped 1.5-cM proximal to Xcdo365 and 1.2-cM distal to Xucw67. These new markers can be used to reduce the size of the DIC chromosome segment selected in marker-assisted selection programs. Markers Nor-B2 and Xucw66 flanking the previous two markers can be used to select against the DIC segment and reduce the linkage drag during the transfer of Gpc-6B1 into commercial bread and pasta wheat varieties. The precise mapping of the high GPC gene, the high frequency of recombinants recovered in the targeted region, and the recent development of a tetraploid BAC library including the Gpc-6B1 DIC allele are the first steps towards the map-based cloning of this gene.

Attachment and Traumatic Stress in Female Holocaust Child Survivors and Their Daughters.

Abstract: Objective: During the Holocaust, extreme trauma was inflicted on children who experienced it. Two questions were central to the current investigation. First, do survivors of the Holocaust still show marks of their traumatic experiences, even after more than 50 years? Second, was the trauma passed on to the next generation? Method: Careful matching of Holocaust survivors and comparison subjects was employed to form a research study design with three generations, including 98 families with a grandmother, a mother, and an infant, who engaged in attachment- and