Showing papers by "University of Haifa published in 2002"

Medicinal mushrooms as a source of antitumor and immunomodulating polysaccharides.

Abstract: The number of mushrooms on Earth is estimated at 140,000, yet maybe only 10% (approximately 14,000 named species) are known. Mushrooms comprise a vast and yet largely untapped source of powerful new pharmaceutical products. In particular, and most importantly for modern medicine, they represent an unlimited source of polysaccharides with antitumor and immunostimulating properties. Many, if not all, Basidiomycetes mushrooms contain biologically active polysaccharides in fruit bodies, cultured mycelium, culture broth. Data on mushroom polysaccharides have been collected from 651 species and 7 infraspecific taxa from 182 genera of higher Hetero- and Homobasidiomycetes. These polysaccharides are of different chemical composition, with most belonging to the group of β-glucans; these have β-(1→3) linkages in the main chain of the glucan and additional β-(1→6) branch points that are needed for their antitumor action. High molecular weight glucans appear to be more effective than those of low molecular weight. Chemical modification is often carried out to improve the antitumor activity of polysaccharides and their clinical qualities (mostly water solubility). The main procedures used for chemical improvement are: Smith degradation (oxydo-reducto-hydrolysis), formolysis, and carboxymethylation. Most of the clinical evidence for antitumor activity comes from the commercial polysaccharides lentinan, PSK (krestin), and schizophyllan, but polysaccharides of some other promising medicinal mushroom species also show good results. Their activity is especially beneficial in clinics when used in conjunction with chemotherapy. Mushroom polysaccharides prevent oncogenesis, show direct antitumor activity against various allogeneic and syngeneic tumors, and prevent tumor metastasis. Polysaccharides from mushrooms do not attack cancer cells directly, but produce their antitumor effects by activating different immune responses in the host. The antitumor action of polysaccharides requires an intact T-cell component; their activity is mediated through a thymus-dependent immune mechanism. Practical application is dependent not only on biological properties, but also on biotechnological availability. The present review analyzes the pecularities of polysaccharides derived from fruiting bodies and cultured mycelium (the two main methods of biotechnological production today) in selected examples of medicinal mushrooms.

One-class svms for document classification

Abstract: We implemented versions of the SVM appropriate for one-class classification in the context of information retrieval. The experiments were conducted on the standard Reuters data set. For the SVM implementation we used both a version of Schoelkopf et al. and a somewhat different version of one-class SVM based on identifying "outlier" data as representative of the second-class. We report on experiments with different kernels for both of these implementations and with different representations of the data, including binary vectors, tf-idf representation and a modification called "Hadamard" representation. Then we compared it with one-class versions of the algorithms prototype (Rocchio), nearest neighbor, naive Bayes, and finally a natural one-class neural network classification method based on "bottleneck" compression generated filters.The SVM approach as represented by Schoelkopf was superior to all the methods except the neural network one, where it was, although occasionally worse, essentially comparable. However, the SVM methods turned out to be quite sensitive to the choice of representation and kernel in ways which are not well understood; therefore, for the time being leaving the neural network approach as the most robust.

Microsatellites: genomic distribution, putative functions and mutational mechanisms: a review.

Abstract: Microsatellites, or tandem simple sequence repeats (SSR), are abundant across genomes and show high levels of polymorphism. SSR genetic and evolutionary mechanisms remain controversial. Here we attempt to summarize the available data related to SSR distribution in coding and noncoding regions of genomes and SSR functional importance. Numerous lines of evidence demonstrate that SSR genomic distribution is nonrandom. Random expansions or contractions appear to be selected against for at least part of SSR loci, presumably because of their effect on chromatin organization, regulation of gene activity, recombination, DNA replication, cell cycle, mismatch repair system, etc. This review also discusses the role of two putative mutational mechanisms, replication slippage and recombination, and their interaction in SSR variation.

Adults' Statistical Literacy: Meanings, Components, Responsibilities

Abstract: Summary Statistical literacy is a key ability expected of citizens in information-laden societies, and is often touted as an expected outcome of schooling and as a necessary component of adults' numeracy and literacy. Yet, its meaning and building blocks have received little explicit attention. This paper proposes a conceptualization of statistical literacy and describes its key components. Statistical literacy is portrayed as the ability to interpret, critically evaluate, and communicate about statistical information and messages. It is argued that statistically literate behavior is predicated on the joint activation of five interrelated knowledge bases (literacy, statistical, mathematical, context, and critical), together with a cluster of supporting dispositions and enabling beliefs. Educational and research implications are discussed, and responsibilities facing educators, statisticians, and other stakeholders are outlined.

From Responsiveness to Collaboration: Governance, Citizens, and the Next Generation of Public Administration

Abstract: The evolution of the New Public Management movement has increased pressure on state bureaucracies to become more responsive to citizens as clients. Without a doubt, this is an important advance in contemporary public administration, which finds itself struggling in an ultradynamic marketplace. However, together with such a welcome change in theory building and in practical culture reconstruction, modern societies still confront a growth in citizens’ passivism; they tend to favor the easy chair of the customer over the sweat and turmoil of participatory involvement. This article has two primary goals: First to establish a theoretically and empirically grounded criticism of the current state of new managerialism, which obscures the significance of citizen action and participation through overstressing the (important) idea of responsiveness. Second, the article proposes some guidelines for the future development of the discipline. This progress is toward enhanced collaboration and partnership among governance and public administration agencies, citizens, and other social players such as the media, academia, and the private and third sectors. The article concludes that, despite the fact that citizens are formal “owners” of the state, ownership will remain a symbolic banner for the governance and public administration–citizen relationship in a representative democracy. The alternative interaction of movement between responsiveness and collaboration is more realistic for the years ahead.

Estimation of the area under the ROC curve.

Abstract: The area under the receiver operating characteristic curve is frequently used as a measure for the effectiveness of diagnostic markers. In this paper we discuss and compare estimation procedures for this area. These are based on (i) the Mann-Whitney statistic; (ii) kernel smoothing; (iii) normal assumptions; (iv) empirical transformations to normality. These are compared in terms of bias and root mean square error in a large variety of situations by means of an extensive simulation study. Overall we find that transforming to normality usually is to be preferred except for bimodal cases where kernel methods can be effective.

There is more to discourse than meets the ears: Looking at thinking as communicating to learn more about mathematical learning

Abstract: Traditional approaches to research into mathematical thinking, such as the study of misconceptions and tacit models, have brought significant insight into the teaching and learning of mathematics, but have also left many important problems unresolved. In this paper, after taking a close look at two episodes that give rise to a number of difficult questions, I propose to base research on a metaphor of thinking-as-communicating. This conceptualization entails viewing learning mathematics as an initiation to a certain well defined discourse. Mathematical discourse is made special by two main factors: first, by its exceptional reliance on symbolic artifacts as its communication-mediating tools, and second, by the particular meta-rules that regulate this type of communication. The meta-rules are the observer’s construct and they usually remain tacit for the participants of the discourse. In this paper I argue that by eliciting these special elements of mathematical communication, one has a better chance of accounting for at least some of the still puzzling phenomena. To show how it works, I revisit the episodes presented at the beginning of the paper, reformulate the ensuing questions in the language of thinking-ascommunication, and re-address the old quandaries with the help of special analytic tools that help in combining analysis of mathematical content of classroom interaction with attention to meta-level concerns of the participants.

The model of ethnic democracy: Israel as a Jewish and democratic state

Abstract: The liberal democratic nation-state is on the decline in the West as a result of globalisation, regionalisation, universalisation of minority rights, multi- culturalism and the rise of ethno-nationalism. While Western countries are decoupling the nation-state and shifting toward multicultural civic democracy, other countries are consolidating an alternative non-civic form of a democratic state that is identified with and subservient to a single ethnic nation. This model, 'ethnic democracy', is presented; its defining features, the circumstances leading to it and the conditions for its stability are elaborated upon; and it is applied to Israel. Contrary to its self-image and inter- national reputation as a Western liberal democracy, Israel is an ethnic democracy in which the Jews appropriate the state and make it a tool for advancing their national security, demography, public space, culture and interests. At the same time, Israel is a democracy that extends various kinds of rights to 1 million Palestinian Arab citizens (16 per cent of the population) who are perceived as a threat. The criticisms against the general model and its applicability to Israel are discussed. The model has already been applied to other countries, but more applications are needed in order to develop it further.

Antecedents and consequences of teacher organizational and professional commitment

Abstract: The purpose of the present study was to examine the distinctive relationships of teacher professional and organizational commitment with participation in decision making and with organizational citizenship behavior (OCB). The data were collected through questionnaires from a sample of 983 teachers at 25 middle schools and 27 high schools in Israel. The results of the structural equation model confirmed the main hypotheses and depicted distinctive patterns of relationships regarding professional commitment and organizational commitment in schools. First, whereas participation in the managerial domain was positively associated with both the professional and the organizational commitment, participation in the technical domain was positively related with only teachers’ professional commitment. Second, professional commitment was positively associated with OCBtoward the student, whereas organizational commitment was positively associated with all three dimensions of OCB(toward the student, the team, and the or...

Covert attention increases spatial resolution with or without masks: Support for signal enhancement

Abstract: Visual attention can increase spatial resolution even when it leads to a decrease in performance. Whether this effect is mediated by reduction of external noise or by signal enhancement is an unsettled question. Although we previously demonstrated that attention can improve speed and accuracy in an acuity task, those experiments made use of a local postmask, which could be considered a source of external noise. In this work, a peripheral cue improved observers' abilities to indicate which side of a Landolt-square target had a gap whether or not a local postmask was used and with both central- and spread-neutral cues. In addition, we documented the presence of visual field inhomogeneities in a resolution task. Given that these experiments presented the target alone with no external noise added (i.e., without distracters or masks), our results indicate that transient attention enhanced the quality of the stimulus representation. Furthermore, because performance in the Landolt-square task indexes resolution, this attentional benefit indicates that transient attention can produce signal enhancement through finer spatial resolution.

A Multifacet Model of Organizational Learning

Abstract: The objective of this article is to map the manyfacets of organizational learning into an integrative and parsimonious conceptual framework that can help researchers and practicioners identify, stu...

Monotonicity testing over general poset domains

Abstract: The field of property testing studies algorithms that distinguish, using a small number of queries, between inputs which satisfy a given property, and those that are 'far' from satisfying the property. Testing properties that are defined in terms of monotonicity has been extensively investigated, primarily in the context of the monotonicity of a sequence of integers, or the monotonicity of a function over the n-dimensional hypercube {1,…,m}n. These works resulted in monotonicity testers whose query complexity is at most polylogarithmic in the size of the domain.We show that in its most general setting, testing that Boolean functions are close to monotone is equivalent, with respect to the number of required queries, to several other testing problems in logic and graph theory. These problems include: testing that a Boolean assignment of variables is close to an assignment that satisfies a specific 2-CNF formula, testing that a set of vertices is close to one that is a vertex cover of a specific graph, and testing that a set of vertices is close to a clique.We then investigate the query complexity of monotonicity testing of both Boolean and integer functions over general partial orders. We give algorithms and lower bounds for the general problem, as well as for some interesting special cases. In proving a general lower bound, we construct graphs with combinatorial properties that may be of independent interest.

Stress-related aftermaths to workplace politics: The relationships among politics, job distress, and aggressive behavior in organizations.

Abstract: Summary In light of the growing theoretical and practical interest on organizational politics, especially its probable impact on work outcomes, two stress-related aftermaths of influence and politics in organizations were examined. On the basis of a model by Ferris, Russ, and Fandt (1989b) the idea was pursued that workplace politics may have a long-range impact on employees’ job distress and aggressive behavior in and around organizations. Three samples (n1 ¼ 155, n2 ¼ 184, n3 ¼ 201) were used to examine direct and indirect/mediating relationships among the research variables. Participants were Israeli employees from the private, public, and third sectors. Findings showed that: (1) job distress was an immediate response to organizational politics across the three types of organization, and (2) job distress proved a possible mediator between organizational politics and aggressive behavior as enacted by the employees themselves. Several theoretical and practical implications of the findings that may extend our knowledge on various stress-related aftermaths of organizational politics are noted. Copyright # 2002 John Wiley & Sons, Ltd.

Emodin--a secondary metabolite with multiple ecological functions in higher plants.

Abstract: Summary The anthraquinone emodin, identified in 17 plant families distributed worldwide, has numerous biological activities, some of which exhibit a wide spectrum of ecological impacts by mediating biotic or abiotic interactions of plants with their environment. Here the evidence for direct and indirect effects of emodin on plant survival and reproduction is reviewed. Emodin in vegetative organs may help protect plants against herbivores, pathogens, competitors and extrinsic abiotic factors (e.g. high light intensities). In unripe fruit pulp, emodin may facilitate seed dispersal by protecting the immature fruit against predispersal seed predation whereas in ripe pulp it may deter frugivores and thus reduce the chances that seeds will be defecated beneath the parent plant. It also accelerates the passage of seeds through the digestive tract, potentially reducing dispersal distance and increasing seed viability upon dispersal. In certain circumstances both of the last two effects could also have negative fitness consequences for plants. Natural selection should favor secondary metabolites with multiple functions because they protect the plants against a variety of unpredictable biotic and abiotic environments. Such metabolites also enhance plant defenses by using different molecular targets of specific enemies through a variety of mechanisms of action. Emodin illustrates the wide and often overlooked potential for chemical multifunctionality in plant secondary metabolites.

The cost of behavioral and psychological symptoms of dementia (BPSD) in community dwelling Alzheimer's disease patients

Abstract: Introduction Behavioral and psychological symptoms of dementia (BPSD) are highly prevalent in Alzheimer's disease (AD) patients. They are a source of distress for the caregivers and one of the main reasons for nursing home placement, which is the major component of the cost of Alzheimer's disease. The aim of the present study was to assess the direct and indirect cost related to the care of BPSD within a prospective study examining the overall cost of AD in Israel. Methods Seventy-one community dwelling AD patients were interviewed. Interviews covered information about the number of caregivers' hours invested in caring for the patient and amount of expenditure such as in-house paid help and payments for day care. Effort devoted to BPSD was defined as the number of hours spent by primary and secondary caregivers in a typical week dealing with BPSD (managing aggression, pacing, attempts to leave the house under inappropriate circumstances, or comforting a hallucinating, depressed or anxious patient). Results The annual indirect cost for management of BPSD in an AD patient was approximately $2665—over 25% of the total annual indirect cost of care ($10 520). The annual direct cost of BPSD of an AD patient was approximately $1450—over 35% of the total annual direct cost of care ($3900). Conclusions Approximately 30% ($4115) of the total annual cost of AD ($14 420) is invested in the direct management of BPSD. Given the importance of BPSD as one of the main components of the cost of AD, future cost studies should be designed to measure the cost of specific components of BPSD and verify which are the most costly aspects of the disease. Despite the considerable methodological difficulties in disentangling the costs of the specific symptoms of AD, cost effectiveness studies of different interventions should be conducted in order to determine the optimal intervention with relation to cost. Copyright © 2002 John Wiley & Sons, Ltd.

Highbrow Cultural Consumption and Class Distinction in Italy, Israel, West Germany, Sweden, and the United States

Abstract: Although some sociologists still connect cultural preferences with social class, others argue thatpostindustrial societies are no longer class-based societies and that contemporary cultural consumption patterns do not simply reflect class positions. This article addresses several theories that characterize the association between class and cultural consumption in contemporary society. It goes on to analyze the effect of class position on highbrow cultural consumption - using both leisure activities and cultural tastes - in Italy, Sweden, West Germany, Israel, and the U.S. It asks whether differences in cultural consumption, given other salient cleavages such as race/ethnicity, gender, and religious observance, are associated with class. Results show that class correlates with highbrow cultural consumption in different ways in the cases studied. The dividing line for consuming highbrow culture is located at the top of the class structure in Israel, the U.S., and Sweden; it is located at the bottom of the class structure in Italy and West Germany. Gender, race, and religious observance are important in conditioning culture consumption, but they do not fully mediate the association between class and cultural tastes. In this article, I analyze the effects of occupational class position, race/ethnicity, gender, and religion on highbrow cultural consumption patterns in Italy, Sweden, West Germany, Israel, and the U.S. My main concern is to examine, through a cross-national comparison, the various ways in which differentiation in cultural

Reading, Syntactic, Orthographic, and Working Memory Skills of Bilingual Arabic-English Speaking Canadian Children

Abstract: This study assessed the reading, language, and memory skills of 56 bilingual Arab-Canadian children age's 9-14. English was their main instructional language, and Arabic was the language spoken at home. All children attended a Heritage Language Program in Toronto where they were taught to read and write Arabic. The children were administered word and pseudo-word reading, language, and working memory tests in English and Arabic. The majority of the children showed at least adequate proficiency in both languages. There was a significant relationship between the acquisition of word and pseudo-word reading working memory, and syntactic awareness skills in the two languages. The poor readers in Arabic had lower scores on all linguistic tasks, except the visual task. There were no significant differences between bilingual English Arabic children and monolingual English-speaking children on the reading, language, and memory tasks. However, bilingual English Arabic children who had reading problems in English had higher scores on English pseudo-word reading and spelling tasks than monolingual English-speaking children with reading disabilities, probably because of positive transfer from the regular nature of Arabic orthography. In this case, bilingualism does not appear to have negative consequences for the development of language reading skills in both languages—Arabic and English—despite the different nature of the two orthographies.

Divison of Labor, Perceived Fairness, and Marital Quality: The Effect of Gender Ideology

Abstract: This study assesses the relations between division of household labor, perceived fairness, and marital quality by comparing three ethnic-religious groups in Israel that reflect traditional, transitional, and egalitarian ideologies. The findings, based on structural equation modeling (SEM) methodology, show that sense of fairness mediates the relation between division of labor and marital quality and gender ideology moderates these relations for women but not for men. Perceived fairness is related to the division of labor for women in egalitarian and transitional families but not in traditional ones. For egalitarian women, a more segregated division of labor is linked directly with lower marital quality whereas for women in transitional families it is mediated by sense of fairness. The findings are discussed on two overlapping levels-conceptual-theoretical and sociocultural-with implications for understanding families in cultural transition. Key Words: division of labor, equity, gender ideology, Isreal, marital quality. In the past decade, there has been growing interest in the causes and consequences of the way in which household tasks are allocated. A large volume of research has focused on predictors of the allocation of household tasks, demonstrating its association with a host of factors including employment and relative earnings of husbands and wives, as well as cultural norms and beliefs. In his review of research on the division of household labor during the 1990s, Coltrane (2000) concluded that although men's relative contributions have increased, women still do at least twice as much routine housework as men. Inequality in the division of household labor, in turn, is associated with women's sense of unfairness, depression, and marital dissatisfaction, whereas men's participation in routine repetitive chores is the primary predictor of marital satisfaction (Coltrane, 2000). In regard to the link between division of household labor and outcome measures such as marital satisfaction, two hypotheses have been posited: (a) The mediating hypothesis of perceived fairness states that inequality in the division of household labor affects marital satisfaction mainly through perceptions of unfairness; and (b) the moderating hypothesis of gender role ideology states that gender ideology shapes the perception of fairness of the division of labor and the extent to which perceived fairness is linked to marital satisfaction, thereby moderating the associations between division of household labor, perceived fairness, and marital quality. Although both hypotheses have received some empirical attention, findings regarding the mediating effect of perceived fairness are mixed and inconclusive. Additionally, research on the moderating effect of gender ideology has typically been discussed in terms of traditional and egalitarian gender ideologies with only scant attention given to families in transition, who are located somewhere in the middle. In concluding his review, Coltrane (2000) recommended that future research should specify in more detail "how the performance of housework in different families is implicated in various cultural, economic, and gender-reproductive processes" (p. 1227) and how gender ideology influences fairness evaluations and individual well-being. Along this line, the present study extends previous research by examining both the mediating and moderating hypotheses through a comparison of three ethnic-religious groups in Israel that reflect traditional, transitional, and egalitarian family patterns. DIVISION OF LABOR AND MARITAL QUALITY: THE MEDIATING EFFECT OF PERCEIVED FAIRNESS Despite the tendency of both women and men to report that the division of labor is fair, research shows significant associations between various characteristics of the division of household labor and perceived justice. In particular, the greater the men's contribution to household tasks, especially those typically relegated to women (Blair & Johnson, 1992; Demo & Acock, 1993; Sanchez, 1994), and the more balanced the relative contribution of husbands and wives to such tasks (DeMaris & Longmore, 1996; Hawkins, Marshall, & Meiners, 1995; Lennon & Rosenfield, 1994), the higher the sense of fairness in regard to division of labor. …

Mechanisms of Amygdala Modulation of Hippocampal Plasticity

Abstract: Basolateral amygdala (BLA) activation by emotional arousal modulates memory-related processes in the hippocampus. We have shown (Akirav and Richter-Levin, 1999b) that activating the BLA before perforant path (PP) tetanization has a biphasic effect on hippocampal plasticity; priming the BLA immediately before PP tetanization results in the enhancement of dentate gyrus (DG) long-term potentiation (LTP) (an "emotional tag"), whereas stimulation in a spaced interval results in the suppression of DG-LTP. Here, we aimed to elucidate the mechanisms underlying BLA modulation of DG-LTP and specifically to examine whether the stress hormones norepinephrine (NE) and corticosterone (CORT) are main mediators of the BLA biphasic effects. We found that the BLA affects hippocampal plasticity in a complex manner; BLA priming enhanced DG-LTP, and both NE and CORT mediated this effect. Furthermore, we found that ipsilateral BLA spaced activation (2 hr before PP tetanization) suppressed DG-LTP and that this suppressive effect was also mediated by NE and CORT. Priming the contralateral BLA enhanced DG-LTP similarly to the ipsilateral enhancement, but neither NE nor CORT mediated this effect. The spaced activation of the contralateral BLA did not suppress DG-LTP. Taken together, these results suggest that differential mechanisms underlie the ipsilateral and contralateral BLA effects on hippocampal plasticity. Hence, the BLA modulates hippocampal memory processes, presumably via the mediation of the stress hormones NE and CORT, to establish a diverse memory of the experience. Possibly, at the onset of an emotional event the stress hormones permissively mediate plasticity. However, their prolonged presence in the system may suppress the cognitive response to stress.

The Structure of the Meaning of Work: A Relative Stability Amidst Change:

Abstract: The theoretical and empirical literature assumes stability of important attitudes and values. Accordingly, this study examined the hypothesis that the structure of the meaning of work will remain stable over time. This hypothesis was tested on two independent samples of the Israeli labour force. The first (n = 407) was a group of individuals who were interviewed twice, once in 1981 and again in 1993. The second was a new representative sample (n = 942) of the labour force, assembled in 1993, to serve as a comparison with the first sample. The findings generally support the hypothesis regarding the stability over time of the structure of the meaning of work concept.

Advantages and disadvantages of telecommuting for the individual, organization and society

Abstract: The phenomenon of telecommuting has implications for individuals and organizations, and society generally. Examines the advantages and disadvantages of telecommuting to the parties involved and affected by it. Key advantages to individuals are increased autonomy and flexibility; to organizations, increased human resource capacity and savings in direct expenses; and to society, a reduction in environmental damage, solutions for special‐needs populations, and savings in infrastructure and energy. Advantages are weighed against disadvantages: to individuals, possible sense of isolation, lack of separation between work and home; to organizations, costs involved in transition to new work methods, training, and damage to commitment and identification with the organization; finally, society is faced with a danger of creating detached individuals. Discusses implications of the suitability of individuals to telecommuting.

Shedding Further Light on the Effects of Various Types and Quality of Early Child Care on Infant-Mother Attachment Relationship: The Haifa Study of Early Child Care

Abstract: The Haifa Study of Early Child Care recruited a large-scale sample (N = 758) that represented the full SES spectrum in Israel, to examine the unique contribution of various child-care-related correlates to infant attachment. After controlling for other potential contributing variables--including mother characteristics, mother-child interaction, mother-father relationship, infant characteristics and development, and the environment--this study found that center-care, in and of itself, adversely increased the likelihood of infants developing insecure attachment to their mothers as compared with infants who were either in maternal care, individual nonparental care with a relative, individual nonparental care with a paid caregiver, or family day-care. The results suggest that it is the poor quality of center-care and the high infant-caregiver ratio that accounted for this increased level of attachment insecurity among center-care infants.

Angiogenesis in epithelian ovarian cancer

Abstract: Angiogenesis, the development of new blood vessels from the existing vasculature, is an essential component of solid tumour growth and metastasis. Several angiogenic factors are expressed by many tumours, suggesting that tumours promote their own vascularisation by activating the host endothelium. This review will discuss various angiogenic stimulators and inhibitors in epithelian ovarian cancer (EOC), including vascular endothelial growth factor and platelet derived endothelial cell growth factor/thymidine phosphorylase. The analysis of tumour vascularisation by microvessel density will also be discussed and the relevance of these markers of angiogenesis in the prognosis of EOC will be assessed.