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Showing papers by "University of Haifa published in 1998"


Journal ArticleDOI
Anna Sfard1
TL;DR: In this article, two such metaphors are identified: the acquisition metaphor and the participation metaphor, and their entailments are discussed and evaluated, and the question of theoretical unification of research on learning is addressed, wherein the purpose is to show how too great a devotion to one particular metaphor can lead to theoretical distortions and to undesirable practices.
Abstract: This article is a sequel to the conversation on learning initiated by the editors of Educational Researcher in volume 25, number 4. The author’s first aim is to elicit the metaphors for learning that guide our work as learners, teachers, and researchers. Two such metaphors are identified: the acquisition metaphor and the participation metaphor. Subsequently, their entailments are discussed and evaluated. Although some of the implications are deemed desirable and others are regarded as harmful, the article neither speaks against a particular metaphor nor tries to make a case for the other. Rather, these interpretations and applications of the metaphors undergo critical evaluation. In the end, the question of theoretical unification of the research on learning is addressed, wherein the purpose is to show how too great a devotion to one particular metaphor can lead to theoretical distortions and to undesirable practices.

3,660 citations


Journal ArticleDOI
TL;DR: The authors tested several hypotheses derived from an extended version of Shamir, House, and Arthur's (1993) theory of charismatic leadership, and used three different samples of subordinates to assess leade...
Abstract: We tested several hypotheses derived from an extended version of Shamir, House, and Arthur's (1993) theory of charismatic leadership. We used three different samples of subordinates to assess leade...

658 citations


Journal ArticleDOI
Batia Laufer1
TL;DR: The authors investigated the gains m three types of English as a Foreign Language vocabulary knowledge, passive, controlled active and free active, in one year of school instruction and examined how these aspects of lexical knowledge are related to one another, and what changes occur in these relauonships after one year.
Abstract: The study investigates the gains m three types of English as a Foreign Language vocabulary knowledge, passive, 'controlled active' and free active, in one year of school instruction It also examines how these aspects of lexical knowledge are related to one another,and what changes occur in these relauonships after one year Gains in vocabulary were measured by comparing two groups of learners with six and seven years of instruction Relauonships among the three areas of knowledge were invesngated by comparing them within the same individuals The results show that passive vocabulary size (as measured by Vocabulary Levels Test) progressed very well, controlled acttve vocabulary (as measured by the productive version of the Levels Test) progressed too but less than the passive Free acuve vocabulary (as measured by Lexical Frequency Profile) did not progress at all Passive vocabulary size was larger than controlled acuve in both groups of subjects, but the gap between the two types of knowledge increased in the more advanced group Passive and controlled acuve size scores correlated with each other well Free active vocabulary, on the other hand, did not correlate with the other two types The results raise several questions about the nature of vocabulary knowledge and the effect of instruction on vocabulary growth

606 citations


Journal ArticleDOI
TL;DR: This article investigated the relationships among three types of vocabulary knowledge (passive, controlled active, and free active) within the same individuals, taking 4variables into consideration: passive vocabulary size, language learning context, second (L2) orforeign (FL), length of residence in L2 context and knowledge of French.
Abstract: This study investigated the relationships among 3 types of vocabularyknowledge (passive, controlled active, and free active) within the same individuals, taking 4variables into consideration: passive vocabulary size, language learning context, second (L2) orforeign (FL), length of residence in L2 context and, among the Canadians, knowledge of French.Participants were adult learners of English in Israel (N = 79) and in Canada (N = 103) at different proficiency levels. We used The Levels Test for passivevocabulary size, a Controlled Active Vocabulary Test and The Lexical Frequency Profile (forlexical richness in free written expression). We found that the 3 dimensions of vocabularyknowledge developed at different rates. Active, particularly free active, vocabulary developedmore slowly and less predictably than did passive vocabulary. Furthermore, the relationshipsamong the 3 dimensions of vocabulary knowledge differed between the 2 learning contexts.Although passive vocabulary was always significantly larger than controlled active and freeactive, the passive-active vocabulary gap was smaller in the FL than in the L2 context. Thebenefits of residence in an L2 context only began to appear after about 2 years, as passivevocabulary was activated and the gap reduced. In the Canadian context, knowledge of Frenchwas an asset at the earlier stages of ESL learning.

368 citations


Journal ArticleDOI
TL;DR: In this paper, a two-faceted approach to organizational learning is presented, which focuses on organizational learning mechanisms, which are institutionalized and cultural in the organizational learning process.
Abstract: This article presents a two-faceted (structural and cultural) approach to organizational learning. The structural facet focuses on organizational learning mechanisms, which are institutionalized st...

361 citations


Journal ArticleDOI
TL;DR: In the Mediterranean forest area of Israel, fires increase runoff and sediment yield rates relative to undisturbed forested land as discussed by the authors, and fire severity increases the potential for erosion in the Mediterranean forests.

288 citations


Journal ArticleDOI
Dana Yagil1
TL;DR: In this paper, the authors examined gender and age-related differences in drivers' normative motives for compliance with traffic laws and in gain-loss considerations related to driving. And they found that younger drivers and male drivers express a lower level of normative motivation to comply with traffic law than do female and older drivers.
Abstract: The study examined gender and age-related differences in drivers’ normative motives for compliance with traffic laws and in gain–loss considerations related to driving. Two age groups of male and female students, totaling 181 respondents, completed a questionnaire measuring several normative motives for compliance with traffic laws, perceived gains and danger involved in the commission of traffic violations, and the frequency of committing various driving violations. The results show that younger drivers and male drivers express a lower level of normative motivation to comply with traffic laws than do female and older drivers. The lowest level of perceived importance of traffic laws relative to other laws was found among young male drivers. The commission of traffic violations was found to be related more to the evaluation of traffic laws among men and younger drivers, compared to women and older drivers. The perceived danger involved in the commission of a driving violation, however, was found to constitute much more of a factor among women than among men before the commission of traffic violations. Perceived gains involved in the commission of violations were more strongly pronounced among older drivers than among younger drivers. Results are discussed concerning different types of attitude–behavior relationships in the context of driving.

265 citations


Journal ArticleDOI
TL;DR: A classification scheme for floral symmetry is contributed that is hoped to resolve some of the confusion resulting from the inconsistent application of terms and a short review of the distribution of floral forms in angiosperm families is presented.
Abstract: Floral symmetry has figured prominently in the study of both pollination biology and animal behavior. However, a confusion of terminology and the diffuse nature of the literature has limited our understanding of the role that this basic characteristic of flower form has played in plant-pollinator interactions. Here, we first contribute a classification scheme for floral symmetry that we hope will resolve some of the confusion resulting from the inconsistent application of terms. Next, we present a short review of the distribution of floral forms in angiosperm families. Finally, we provide a list of hypotheses and, when available, supporting evidence for the causes of the evolution of floral symmetry.

244 citations


Journal ArticleDOI
TL;DR: The idea of social learning is not new, having been an important part of early developments of the science of psychology (Munsterberg as mentioned in this paper, 1919) as formulated by Munsterberg [1914, cited in Cole & Engestrom, 1993).
Abstract: Social learning is in the air. Daily observations and experiences as well as recent scholarly traditions suggest that a certain amount of learning takes place beyond the confines of the individual mind. Learning appears to involve social aspects. Scenarios ranging from a group of children collaboratively trying to solve the question of how to construct a kite to a university professor writing a research paper with a colleague advance the case for a social side to learning. But impressions do not make social learning an obvious category. Are there any theoretical and empirical grounds to justify social learning as a distinctive phenomenon? Is there anything qualitatively different in this kind of learning to distinguish it from the familiar individual conception of learning? Can one make the case that social learning is more than an epiphenomenon or individual learning multiplied, that the social aspects of learning are anything more than the kind of secondary help a learner might get from audiovisual displays, bookmarks, and road signs? If we can raise the question of whether social learning is a valid and viable phenomenon, the opposite question might equally well be raised: Is it not possible that solo learning is simply a figment of the traditional laboratory-based psychology, on the one hand, and of a socially shared respect for the individual qua individual, on the other? The idea of social learning is not really new, having been an important part of early developments of the science of psychology (\"folkspsychology,\" as formulated, for example, by Munsterberg [1914, cited in Cole & Engestrom, 1993]). This branch of psychology fell into neglect because of its Gestalt-like nature and thus its alleged lack of rigor, its central phenomena left to anthropology and sociology to handle. It was distinguished from the more rigorous laboratory-based, experimentally oriented, and far more prestigious psychology of Ebbinghouse. Social learning has thus continued to be largely ignored by psychologists over the years, relegated at best to the study of background context, not really on a par with the learning of the individual (Gardner, 1985). This relative neglect now appears to have been corrected. With the growing interest in Vygotsky's theory, retrospective examinations of the role of social inter-

240 citations


Journal ArticleDOI
TL;DR: The authors examines how cyclical arts festivals transform places from being everyday settings into temporary environments that contribute to the production, processing and consumption of culture, concentrated in time and place, highlighting latent tensions between festival as art and economics, between culture and cultural politics.
Abstract: Despite their ubiquity and cultural prominence, academic study of arts festivals has been neglected. This article examines how cyclical arts festivals transform places from being everyday settings into temporary environments that contribute to the production, processing and consumption of culture, concentrated in time and place. Moreover, festivals also provide examples of how culture is contested. Support for the arts is part of a process used by elites to establish social distance between themselves and others. Festivals have traditionally been innovative and have always been controlled. In the past, artistic directors wielded this control but recent attempts by commercial interests to control festivals reflect a wider situation in which marketing agencies and managers are transforming arts and culture into arts and culture industries. Today, promoting arts festivals is related to place promotion, and this encourages 'safe' art forms. This highlights latent tensions between festival as art and economics, between culture and cultural politics.

224 citations


Journal ArticleDOI
TL;DR: In this article, a new approach to the intergenerational transmission of Holocaust experiences, by focusing on attachment theory, is proposed, which is used as a framework for interpretation of the results of three studies on Holocaust survivors and their offspring, from different countries (The Netherlands, Canada, and Israel).
Abstract: In this paper, we advance a new approach to the intergenerational transmission of Holocaust experiences, by focusing on attachment theory The approach is used as a framework for interpretation of the results of three studies on Holocaust survivors and their offspring, from different countries (The Netherlands, Canada, and Israel), and based on different conceptual approaches and methods of data collection (quantitative as well as qualitative)

Journal ArticleDOI
TL;DR: A new method to determine stigma receptivity by using a Peroxtesmo esterase indicator paper liquid (one paper+1 ml water) and to locate the receptive area is described.
Abstract: We describe a new method to determine stigma receptivity by using a Peroxtesmo esterase indicator paper liquid (one paper+1 ml water). This technique enables the researcher to check instantly the receptivity of various types of stigmas and to locate the receptive area.

Journal ArticleDOI
Noam Soker1
TL;DR: In this article, the influence of planetary systems on the location of stars on the Hertzsprung-Russel diagram is examined, and it is shown that the presence of a planetary system can explain some anomalies in horizontal branch morphologies.
Abstract: I examine the influence of planets on the location of stars on the Hertzsprung-Russel diagram as the stars turn to the horizontal branch. As stars that have planetary systems evolve along the red giant branch and expand, they interact with the close planets, with orbital separations of 5 AU. The planets deposit angular momentum and energy into the red giant stars' envelopes, both of which are likely to enhance mass loss on the red giant branch. The enhanced mass loss causes the star to become bluer as it turns to the horizontal branch. I propose that the presence of planetary systems, through this mechanism, can explain some anomalies in horizontal branch morphologies. In particular, planetary systems may be related to the second parameter, which determines the distribution of horizontal branch stars on the Hertzsprung-Russel diagram. The presence of planets, though, cannot be the only factor that influences the second parameter. The distribution of planets' properties (e.g., mass, orbital separation, prevalence) in a specific globular cluster depends on several properties of the globular cluster itself (e.g., shape, density). This dependence may explain some of the anomalies and variations in the horizontal branch morphologies between different globular clusters. The proposed scenario predicts that surviving massive planets or brown dwarfs orbit some of the extreme blue horizontal branch stars, at orbital periods of ~10 days.

Journal ArticleDOI
TL;DR: Results indicate that an extensive genetic response is induced in mammalian brain after glutamate receptor activation, and imply that a significant proportion of this activity is coinduced by LTP, suggesting that multiple cellular mechanisms underlie long-term plasticity of the nervous system.
Abstract: Long-term plasticity of the central nervous system (CNS) involves induction of a set of genes whose identity is incompletely characterized. To identify candidate plasticity-related genes (CPGs), we conducted an exhaustive screen for genes that undergo induction or downregulation in the hippocampus dentate gyrus (DG) following animal treatment with the potent glutamate analog, kainate. The screen yielded 362 upregulated CPGs and 41 downregulated transcripts (dCPGs). Of these, 66 CPGs and 5 dCPGs are known genes that encode for a variety of signal transduction proteins, transcription factors, and structural proteins. Seven novel CPGs predict the following putative functions:cpg2—a dystrophin-like cytoskeletal protein;cpg4—a heat-shock protein:cpg16—a protein kinase;cpg20—a transcription factor;cpg21—a dual-specificity MAP-kinase phosphatase; andcpg30 andcpg38—two new seven-transmembrane domain receptors. Experiments performed in vitro and with cultured hippocampal cells confirmed the ability of thecpg-21 product to inactivate the MAP-kinase. To test relevance to neural plasticity, 66 CPGs were tested for induction by stimuli producing long-term potentiation (LTP). Approximately one-fourth of the genes examined were upregulated by LTP. These results indicate that an extensive genetic response is induced in mammalian brain after glutamate receptor activation, and imply that a significant proportion of this activity is coinduced by LTP. Based on the identified CPGs, it is conceivable that multiple cellular mechanisms underlie long-term plasticity of the nervous system.

Journal ArticleDOI
Eviatar Nevo1
TL;DR: The population genetics and ecology of two important progenitors of cereals wild, wheat and barley are illustrated, showing how complementary in situ and ex situ conservation is imperative across the geographic range of these species, to safeguard their immensely important genetic resources for crop improvement.
Abstract: The current alarming global crisis and extinction of biodiversity affect negatively the planet's biosphere. Conservation of biodiversity is one attempt to alleviate the pending extinction of the biosphere by humans. Genetic diversity, the basis of evolution by natural selection, is gravely threatened in the progenitors of cultivated plants and its exploration, evaluation, conservation in situ and ex situ is imperative to guarantee sustainable development. This is illustrated by the population genetics and ecology of two important progenitors of cereals wild, wheat and barley. The wild cereals are rich in adaptive genetic diversity in the Fertile Crescent, primarily in Israel, which is their center of origin and diversity. The 40–55% intrapopulation diversity level in the wild cereals contrasts sharply with the average of 80% in outbreeders. Genetic diversity in wild wheat and barley is structured, particularly in wild emmer wheat, as an 'archipelago' ecological and genetic structure. These include central, semi-isolated and ecologically peripheral and marginal isolated populations, where specific alleles and allele combinations predominate as coadapted blocks of genes, adaptive to diverse ecological stresses. These involve both physical (climatic and edaphic) and biotic (pathogens and parasites) stresses at macro- and microgeographical scales. Complementary in situ and ex situ conservation is imperative across the geographic range of these species, to safeguard their immensely important genetic resources for crop improvement.

Journal ArticleDOI
TL;DR: Students in constructivist learning environments should beware of being led into a technological promised land that redefines the nature of constructionist learning environments, says this work.

Journal ArticleDOI
TL;DR: An algorithm for the variational inequality problem on convex sets with nonempty interior establishes full convergence to a solution with minimal conditions upon the monotone operatorF, weaker than strong monotonicity or Lipschitz continuity, for instance, and including cases where the solution needs not be unique.
Abstract: We present an algorithm for the variational inequality problem on convex sets with nonempty interior. The use of Bregman functions whose zone is the convex set allows for the generation of a sequence contained in the interior, without taking explicitly into account the constraints which define the convex set. We establish full convergence to a solution with minimal conditions upon the monotone operatorF, weaker than strong monotonicity or Lipschitz continuity, for instance, and including cases where the solution needs not be unique. We apply our algorithm to several relevant classes of convex sets, including orthants, boxes, polyhedra and balls, for which Bregman functions are presented which give rise to explicit iteration formulae, up to the determination of two scalar stepsizes, which can be found through finite search procedures. © 1998 The Mathematical Programming Society, Inc. Published by Elsevier Science B.V.

Journal ArticleDOI
TL;DR: The impact of the predator, Notonecta maculata, on invertebrate community structure was investigated by a combination of a natural pool survey, an outdoor artificial pool experiment, and a laboratory prey preference experiment.
Abstract: 1. The impact of the predator, Notonecta maculata, on invertebrate community structure was investigated by a combination of a natural pool survey, an outdoor artificial pool experiment, and a laboratory prey preference experiment. 2. In a survey of forty natural pools in the Negev Desert, Israel, pelagic/neustonic species richness and overall species richness, but not benthic species richness, were negatively associated with N. maculata density. 3. In the artificial pool experiment, in which the presence or absence of Notonecta was manipulated, Notonecta caused a reduction in the richness of species colonizing the pools. Notonecta strongly reduced densities of the pelagic dipterans, Culiseta longiareolata (often 100% reduction of later-instar larvae and pupae) and ephydrids. Fewer Culiseta egg rafts were found in Notonecta pools, indicating that part of the observed reduction of Culiseta is not due to consumption of Culiseta larvae by Notonecta, but to habitat selection by ovipositing Culiseta females in response to risk of predation by Notonecta. Notonecta did not affect densities of (benthic) chironomids or the small cladoceran, Ceriodaphnia cf. quadrangula. Laboratory assessments of selectivity by Notonecta for the various prey matched patterns found in the field experiment. 4. This work provides strong evidence that N. maculata is an important organizer of community structure: it strongly reduces or even eliminates larger pelagic or neustonic species, but does not affect densities of small or benthic species.

Journal ArticleDOI
TL;DR: The vast majority of states in the international system, democratic and non-democratic, are multi-ethnic (Gurr 1993) as mentioned in this paper, and membership in the political structure called a state is the single criterion for belonging to the state and for granting equal opportunity to all members of the system.
Abstract: The vast majority of states in the international system, democratic and non-democratic, are multi-ethnic (Gurr 1993). A liberal-democratic multi-ethnic state serves the collective needs of all its citizens regardless of their ethnic affiliation, and citizenship—legally recognized membership in the political structure called a state—is the single criterion for belonging to the state and for granting equal opportunity to all members of the system. Whether a multi-ethnic democratic state should provide group rights above and beyond individual legal equality is an ongoing debate (Gurr & Harff 1994).

Journal ArticleDOI
Ora Gilbar1
TL;DR: The main finding indicates that health social workers who have a strong sense of coherence experience less burnout than those with a weak sense ofCoherence.
Abstract: The aim of this study was to determine whether a strong sense of coherence as a coping strategy affects burnout in health social workers. The research sample consisted of 31 social workers in the field of physical illness, 21 in the field of mental illness, and 29 in the field of the handicapped. The main finding indicates that health social workers who have a strong sense of coherence experience less burnout than those with a weak sense of coherence. More specifically, the findings indicate that the manageability component of sense of coherence predicts emotional exhaustion.

Journal ArticleDOI
TL;DR: The results obtained suggest that a relatively small number of microsatellites can be used for the estimation of genetic diversity in wild material of T. dicoccoides, and will be useful in the identification of suitable parents for the development of mapping populations for tagging yellow-rust resistance genes derived from the progenitor of cultivated wheat.
Abstract: Stripe rust (yellow rust), caused by Puccinia striiformis f. sp. tritici, is one of the most important diseases of wheat throughout the world. Wild emmer wheat, Triticum dicoccoides, the progenitor of cultivated wheat, was found to be a valuable source for novel stripe-rust-resistance genes. The objective of the present study was to estimate the extent of genetic diversity among the wild emmer wheat accessions, previously identified as highly resistant to stripe rust, in order to select suitable parents for genetic-mapping studies. Twenty three wheat microsatellite (WMS) markers were used to detect DNA polymorphism among 21 accessions of T. dicoccoides, which included 19 resistant and two susceptible accessions originating mainly from the center of origin and diversity in the Upper Galilee and Hermon Mountain in northern Israel. In addition, two Triticum durum and one Triticum aestivum lines were also included in the analysis. The 23 WMS markers used were located on 23 chromosome arms, representing all 14 chromosomes of genomes A and B of wheat, and revealed a total of 230 alleles. The number of alleles ranged from 5 to 18, with an average of ten alleles per WMS. Genetic dissimilarity values between genotypes, calculated by the WMSderived data, were used to produce a dendrogram of the relationships among accessions using the unweighted pair-group method with arithmetic averages (UPGMA). The results showed that all of the wild emmer wheat accessions could be distinguished. Most of the resulting groups were strongly related to the ecogeographical origin of the accessions, indicating that the genetic diversity of T. dicoccoides is correlated with geographic distribution. The three major groups were the Rosh Pinna group (north of the Sea of Galilee), the Mount Hermon group (north of the Golan Heights) and Mount Kena’an group (Upper Galilee). The genetic similarity (GS) of the 21 T. dicoccoides accessions based on WMS results averaged 0.31. As expected, the T. durum and T. aestivum lines were grouped separately from the T. dicoccoides accessions. The results obtained suggest that a relatively small number of microsatellites can be used for the estimation of genetic diversity in wild material of T. dicoccoides. These results will be useful in the identification of suitable parents for the development of mapping populations for tagging yellow-rust resistance genes derived from T. dicoccoides. Furthermore, future work could test the adaptive evolutionary significance of microsatellites in natural populations of wild emmer wheat.

Journal ArticleDOI
TL;DR: The results indicate that a within-context underwater trauma has both acute and lasting behavioral consequences which can be assessed using a spatial memory test in the context of the trauma.
Abstract: As a consequence of a brief but significantly extreme stressor, an individual will experience a stress response, which may sometimes develop into Acute Stress Disorder (ASD) or Post-Traumatic Stress Disorder (PTSD). Though a rat model for ASD and PTSD is not expected to encompass the richness and complexity of the disorders in humans, it will enable the study of the common underlying mechanisms that generate the disorders, the study of pre-trauma etiological aspects of the disorders and the screening of drugs with potential relevance to the treatment of the disorders. One well-documented aspect of PTSD is the enhancing influence of contextual elements on the appearance of symptoms of the post-stress trauma. To exploit this effect, we have chosen to assess the effects of an underwater trauma in the Morris water maze since the effects of such trauma on memory and attention can be later evaluated in the context of the trauma. At both 1 h and 3 weeks after the trauma, significant behavioral deficits were observed in the water maze. The effects of the underwater trauma on the performance of rats in the water maze were context specific. Underwater trauma in a different (out-of-context) water container had no effects on the ability of rats to perform a spatial memory task in the water maze. An elevated level of anxiety was found in the plus maze test, independently of whether the trauma was performed in the water maze or in a different (out-of-context) water container. The results indicate that a within-context underwater trauma has both acute and lasting behavioral consequences which can be assessed using a spatial memory test in the context of the trauma. The results are discussed in relation to their relevance to stress and PTSD.

Journal ArticleDOI
TL;DR: It was evident throughout all the experiments that a single application of phosphates was effective in suppressing the lesions of powdery mildew on the diseased foliage of cucumber, greenhousegrown roses, field grown mango, nectarine and grapevine.

Journal ArticleDOI
TL;DR: For example, this article found that students in reform curricula, who are encouraged to construct their own conceptual and procedural knowledge of proportionality through collaborative problem solving activities, perform better than students with more traditional, teacher-directed instructional experiences.
Abstract: Contextual problems involving rational numbers and proportional reasoning were presented to seventh grade students with different curricular experiences. There is strong evidence that students in reform curricula, who are encouraged to construct their own conceptual and procedural knowledge of proportionality through collaborative problem solving activities, perform better than students with more traditional, teacher-directed instructional experiences. Seventh grade students, especially those who study the new curricula, are capable of developing their own repertoire of sense-making tools to help them to produce creative solutions and explanations. This is demonstrated through analysis of solution strategies applied by students to a variety of rate problems.

Journal ArticleDOI
Noam Soker1
TL;DR: In this article, the authors proposed an explanation for the positive correlation of bipolar planetary nebulae with massive progenitors in the paradigm of binary system progenitor, in which the secondary diverts a substantial fraction of the mass lost by the asymptotic giant branch (AGB) primary.
Abstract: We propose an explanation for the positive correlation of bipolar planetary nebulae with massive progenitors in the paradigm of binary system progenitors. We list 10 critical observations, and argue that single-star models for the formation of bipolar planetary nebulae encounter difficulties complying with these observations. On the other hand, binary system progenitors can naturally explain these key observations, and in addition explain the rich varieties of structures possessed by bipolar planetary nebulae. Based on three of the critical observations, and on previous works by Corradi and Schwarz and by Morris, we postulate that the progenitors of bipolar planetary nebulae are binary stellar systems in which the secondary diverts a substantial fraction of the mass lost by the asymptotic giant branch (AGB) primary, but the systems avoid the common envelope phase for a large fraction of the interaction time. The positive correlation of bipolar planetary nebulae with massive progenitors, M 2 M☉, is attributed to the larger ratios of red giant branch (RGB) to AGB radii which low-mass stars attain, compared with massive stars. These larger radii on the RGB cause most stellar binary companions, which potentially could have formed bipolar planetary nebulae if the primary had been on the AGB, to interact with low-mass primaries already on the RGB. This scenario predicts that the central stars of most bipolar planetary nebulae are in binary systems having orbital periods in the range of a few days to few times 10 yr.

Book
01 Jan 1998
TL;DR: In this article, a model is presented which attempts to explain the observer's cognitive competence, and its limits, in being able to interpret the silent answer, making a distinction between intentional silence and non-intentional silence.
Abstract: The book deals initially with the interpretation of the silent answer to a question. From a semiotic approach to the contrast between silence and speech mainly within a Greimasian framework, the discussion turns to the application of pragmatic tools such as conversational analysis and adjacency pairs to the interpretation of silence. A model is presented which attempts to explain the observer’s cognitive competence, and its limits, in being able to interpret the silent answer. A basic distinction is also made between intentional silence (the refusal to answer) and non-intentional silence (the psychological inability to answer). The interpretation of silence is extended from a theoretical viewpoint to an analysis of various discourse types. Firstly, silence in the legal world: the accused’s and the witness’s right of silence, the right of legal authorities to silence the broadcasting of direct speech. The author then analyzes the silencing of characters in a literary text (Jane Austen’s Pride and Prejudice ), in a biblical text (Moses and his speech impediment in Exodus), in opera (Moses’ silence in Schoenberg’s opera Moses und Aron ) and in the cinema. Here, after the initial discussion of Ingmar Bergman’s The Silence , focus is shifted to the generation gap and the representation of silence by song in Mike Nichols’ The Graduate .

Journal ArticleDOI
TL;DR: The authors investigated the effect of vowels on reading accuracy in Arabic orthography and found that vowels had a significant effect on reading performance of poor and skilled readers in reading each of the four kinds of written Arabic texts.
Abstract: While much is known about Latin orthography little is known about Arabic orthography. This study investigates the effect of vowels on reading accuracy in Arabic orthography. Participants were 64 native Arabic speakers. Four kinds of written Arabic texts were administered: narrative, informative, poetic and Koranic. Three texts of each kind were presented in three reading conditions: correctly vowelized, unvowelized and wrongly vowelized. Results indicated that vowels had a significant effect on reading accuracy of poor and skilled readers in reading each of the four kinds of texts. The results are discussed in light of the concept that more cross-cultural considerations should be made in reading theory today.

Journal ArticleDOI
Dana Yagil1
TL;DR: In this article, the authors examined the attribution of charisma to socially close and distant leaders and found that the ascription of extraordinary traits to the leader and the perception both of the leader as a behavioral model and of his confidence in the individual were related to a willingness to accept the leader's ideas.
Abstract: This study examined the attribution of charisma to socially close and distant leaders. Respondents were 554 Israeli combat soldiers who completed five questionnaires describing their perceptions of either their platoon commander or their battalion commander. The results showed that the attribution of charisma to socially close leaders is related to the ascription of extraordinary traits to the leader and to the perception both of the leader as a behavioral model and of his confidence in the individual. The attribution of charisma to distant leaders was related to a willingness to accept the leader's ideas, the perceived confidence of the leader in the group, the ascription of extraordinary traits to the leader, and a general positive impression of the leader. The results are discussed with regard to the influence of situational variables on the attribution of leadership qualities.

Journal ArticleDOI
TL;DR: Results indicate a lower level of agonistic motivation (flank marking) and sexual interest towards kin than nonkin and demonstrate a phenotype matching mechanism for kin recognition based on differences between odours from kin and nonkin.