Showing papers by "University of Haifa published in 1994"

A multiprojection algorithm using Bregman projections in a product space

Abstract: Generalized distances give rise to generalized projections into convex sets. An important question is whether or not one can use within the same projection algorithm different types of such generalized projections. This question has practical consequences in the area of signal detection and image recovery in situations that can be formulated mathematically as a convex feasibility problem. Using an extension of Pierra's product space formalism, we show here that a multiprojection algorithm converges. Our algorithm is fully simultaneous, i.e., it uses in each iterative stepall sets of the convex feasibility problem. Different multiprojection algorithms can be derived from our algorithmic scheme by a judicious choice of the Bregman functions which govern the process. As a by-product of our investigation we also obtain blockiterative schemes for certain kinds of linearly constraned optimization problems.

Memory in naturalistic and laboratory contexts: Distinguishing the accuracy-oriented and quantity-oriented approaches to memory assessment.

Abstract: A distinction is drawn between the quantity-oriented approach to memory that has dominated traditional laboratory research, and the accuracy-oriented approach that is emerging in the study of everyday memory. This distinction is shown to underlie some troubling confusions in the interpretation of empirical findings. In particular, the recall-recognition paradox, which involves the claimed superiority of recall over recognition memory in naturalistic settings, is shown to stem from the common confounding between memory property (quantity vs. accuracy) and 2 other variables that have not generally been distinguished--test format (production vs. selection) and report option (free vs. forced reporting). Three laboratory experiments reveal the fundamentally different roles played by report option and test format in accuracy-based and quantity-based memory research. Implications for memory assessment, metamemory, and the everyday-laboratory controversy are discussed.

Co-monotone allocations, Bickel-Lehmann dispersion and the Arrow-Pratt measure of risk aversion

Abstract: For every integrable allocation (X 1,X 2, ...,X n ) of a random endowmentY=Σ =1/ X i amongn agents, there is another allocation (X 1*,X 2*, ...,X n *) such that for every 1≤i≤n,X i * is a nondecreasing function ofY (or, (X 1*,X 2*, ...,X n *) areco-monotone) andX i * dominatesX i by Second Degree Dominance. If (X 1*,X 2*, ...,X n *) is a co-monotone allocation ofY=Σ =1/ X i *, then for every 1≤i≤n, Y is more dispersed thanX i * in the sense of the Bickel and Lehmann stochastic order. To illustrate the potential use of this concept in economics, consider insurance markets. It follows that unless the uninsured position is Bickel and Lehmann more dispersed than the insured position, the existing contract can be improved so as to raise the expected utility of both parties, regardless of their (concave) utility functions.

Mountain pass theorems and global homeomorphism theorems

Abstract: We show that mountain-pass theorems can be used to derive global homeomorphism theorems. Two new mountain-pass theorems are proved, generalizing the “smooth” mountain-pass theorem, one applying in locally compact topological spaces, using Hofer’s concept of mountain-pass point, and another applying in complete metric spaces, using a generalized notion of critical point similar to the one introduced by Ioffe and Schwartzman. These are used to prove global homeomorphism theorems for certain topological and metric spaces, generalizing known global homeomorphism theorems for mappings between Banach spaces.

The Lexical Profile of Second Language Writing: Does It Change Over Time?

Abstract: The paper examines changes in the productive lexicon of advanced second language learners' writing over a period of one academic year. Sets of compositions of the same learners were analyzed in ter...

Gender differences in the journey to work

Abstract: It is now well established in geographic research that women commute shorter distances to work than men. This paper attempts to explore the common features that have emerged from the last two decades of research in various places within a metropolitan context. Three main sets of factors that may cause women to commute shorter distances are recognized: residence, employment, and transportation—each containing both social and spatial aspects. The analysis is centered around the spatial aspect. Most research on employed women seems to be characterized by distinguishing between the central city and the suburbs and thus the conclusions focus mostly upon this. An international comparison of different places shows that gender differences in commuting almost always are greater in the suburbs, from the point of view of both residential and employment dispersions. Directions for future research are suggested. Comparable methodologies will enable the inclusion of additional cities and will broaden the comparison. Th...

Sleeping out-of-home in a kibbutz communal arrangement: It makes a difference for infant-mother attachment

Abstract: Attachment classification distributions of infant-mother dyads living in 2 types of Israeli kibbutzim were compared. The subjects were 48 infants, 14-22 months old (M = 18.29 months); 13 boys and 10 girls were from 23 kibbutz infants' houses with communal sleeping arrangements, and 13 boys and 12 girls were from 25 kibbutz infants' houses with home-based sleeping arrangements. The 2 groups did not differ on infants' temperament and early life events, mother-infant play interaction, quality of infants' daytime environment, or any of several maternal variables. Among the home-based infants, 80% were securely attached to their mothers versus 48% of the infants in communal sleeping arrangements. No avoidant relationships were found. Including the disorganized-disoriented attachment classification (44% in the communal group, 32% in the home-based group) did not change the results. We argue that the communal sleeping arrangement presents a childrearing environment that deviates markedly from the environment of evolutionary adaptedness.

Reading Proficiency and Orthography Evidence from Hebrew and English

Abstract: We conducted two experiments to test whether the orthography of readers’ first or second languages affects their reading time and comprehension in each. In both experiments, very skilled bilinguals read texts translated from Hebrew to English, or from English to Hebrew. Half the texts were originally written in Hebrew and the other half in English. In the first experiment, 24 native Hebrew speakers read two passages of four texts in the Hebrew version. Each read one of the texts voweled and the other one unvoweled. Twelve native English speakers read two passages from the same four texts in English. Participants in the study were either students or teachers at the University of Haifa. The English native speakers read the EngLish texts significantly faster than the native Hebrew speakers read the same texts in their Hebrew version. The origin of the text (English or Hebrew) and vowelization were nonsignificant, as was any interaction between the main factors. The comprehension of the Hebrew voweled texts was nearly significantly better than was the comprehension of the Hebrew unvoweled texts. In the second experiment, 24 advanced bilingual, Hebrew native speakers read two passages in Hebrew (one voweled and the other unvoweled) and two in English. Again, the reading time in English was significantly shorter. Post-hoc comparisons showed that readingtime was shorter in English than in unvoweled Hebrew, but not shorter than in voweled Hebrew. Comprehension of English was not significantly different from comprehension of voweled Hebrew, but was significantly better than comprehension of unvoweled Hebrew.

Sites of memory: Discourses of the past in Israeli pioneering settlement museums

Abstract: Heritage museums as sites of cultural production are explored in terms of the distinction drawn by historians between “memory” and “history,” which denotes fundamentally opposed orientations towards the past. The discursive practices employed by museum guides in orally mediating the material displays in Israeli settlement museums are examined in relation to this distinction, suggesting the need to develop a more nuanced view of the relationship between “history” and “memory” as dialectically defined orientations to the past, which combine ritual enactment and critical reflection in contexts of collective remembering. Strategies identified in museum interpretation include the use of a rhetoric of factuality, the narrative appropriation of objects, and the establishment of an indexical relationship between the museum's “master‐narrative” and its localized “object stories.” Some implications are discussed for exploring culturally focal “sites of memory” as part of a critically oriented, auto‐ethnography.

Learning science in a cooperative setting: Academic achievement and affective outcomes

Abstract: A learning unit in earth science was taught to high school students, using a jigsaw-group mastery learning approach. The sample consisted of 73 students in the experimental group and 47 students who learned the topic in an individualized mastery learning approach. The study lasted 5 weeks. Pretests and posttests on academic achievement and affective outcomes were administered. Data were treated with an analysis of covariance. The results show that students of the experimental group achieved significantly higher on academic outcomes, both normative and objective scores. On the creative essay test, the differences in number of ideas and total essay score were not significant between the groups, although the mean scores for number of words were higher for the individualized mastery learning group. On the affective domain, jigsaw-group mastery learning students scored significantly higher on self-esteem, number of friends, and involvement in the classroom. No differences were found in cohesiveness, cooperation, competition, and attitudes toward the subject learned. The results are discussed through the evaluation and comparison of the two methods of instruction used in this study. The cooperative learning movement began in junior high schools as part of the desegregation process, aiming at facilitating positive ethnic relations and increasing academic achievement and social skills among diverse students (Aronson, Stephan, Sikes, Blaney, & Snapp, 1978; Sharan & Hertz-Lazarowitz, 1980; Slavin, 1980). However, elementary teachers quickly recognized the potential of cooperative methods, and such methods were adopted freely in elementary schools before becoming widespread on the junior and senior high level. It has only been during the past few years that application of cooperative learning has been studied extensively with these older students. Cooperative learning methods generally involve heterogeneous groups working together on tasks that are deliberately structured to provide specific assignments and individual contributions from each group member. Cognitive as well as social benefits are expected, as students clarify their own understanding and share their insights and ideas with each other as they interact within the group (Deutsch, 1949). Experiments in the science laboratory have always required students to work in groups of two to four, due to the constraints of experimental processes and limited equipment and sup- plies. Thus, science courses are a natural curriculum area for examining cooperative learning practices. Now that cooperative methods are being refined to develop particular capabilities in the students, science teachers need to examine ways of structuring specific tasks to achieve the academic, affective, and socialization goals for their students. Although most of the studies of cooperative learning in the high school science classroom have centered around the cognitive outcomes of achievement testing and process skills, affective and social outcomes are also significant with students of this age. But few studies in science classes have attempted to assess such aspects of students' progress. As part of a previous revision, the science faculty at the high school where this study was conducted developed an exemplary individualized mastery learning (1ML) program for teaching science. This program seemed to alleviate the severe motivational problems and the extreme individual differences among the students in this rural/bhe-collar community. Students learned to work independently on their science studies. They had almost no lectures and few large group activities. As they worked through their assignments, however, they were free to interdct with other students. Looking in on a typical class, one would see several clusters of two or three students working together, sometimes tutoring each other, sometimes just talking through an assignment. Yet at least half of the class members would be working all alone. The importance of the overall social setting in the classroom as it relates to learning (Bruner, 1986, p. 86) and the central function of social interaction as learning occurs (Vygotsky, 1978, p. 106) seemed to have been ignored. Therefore, group mastery learning (GML), a cooperative learning tech- nique, was suggested as an antithesis to IML for teaching science over short periods. The cooperative mode of instruction considers learning as a cognitive as well as a social process, where students interact with each other as well as the teacher. To bring the social dimension back to science classrooms, the researchers chose to imple- ment GML in Grades 1 I and 12. The goal of the study was to investigate the GML's impact of the method on the individual student's academic achievement, creativity, self-esteem, and number of friends and on the overall learning environment of the classrooms. The researchers were also concerned with the students' attitudes toward earth science, the course being taught at the time of the experiment. Both cognitive and affective outcomes for students who participated in the cooperative GML approach were compared with outcomes for students who studied the same topic in an IML approach. The study addressed a number of questions related to academic and nonacademic outcomes of the two methods of study. First, it sought to determine whether academic achievement of the students taught in the cooperative GML mode would be different from the achievement of students who learned in an individualized method. Second, it sought to determine whether gains or losses would be seen in nonacademic outcomes, such as classroom learning environment, social relations, and students' self-esteem experienced by the students. The results of this study may support more use of cooperative learning in high school science.

Chromosomal speciation and adaptive radiation of mole rats in Asia Minor correlated with increased ecological stress.

Abstract: The evolutionary forces causing chromosomal speciation and adaptation are still enigmatic. Here we tested the Israel evolutionary model of positive association of diploid chromosome number (2n) and genetic diversity with aridity stress in subterranean mole rats, on a 30-times-larger scale in Asia Minor. We analyzed both karyotype and allozyme diversity across Turkey, based on 37 allozymic loci in 20 localities of the Spalax leucodon and 4 localities of the Spalax ehrenbergi superspecies. We found extensive chromosomal speciation in S. leucodon (2n = 38, 40, 50, 54, 60, and 62) and in S. ehrenbergi (2n = 52, 56, and 58), presumably representing from 14 to > 20 additional biological species. Genetic diversity indices were low, but, like the chromosome number (2n), positively correlated with aridity stress, increasing centripetally from the periphery toward geologically young, arid, and climatically unpredictable central Anatolia. Nei's genetic distance D across all populations averaged 0.174 (range 0.002-0.422), supporting, combined with 2n and ecogeography, the biological species status of most tested populations. Chromosome evolution is the basis of speciation and adaptation in Spalax; it provides both postmating reproductive isolation, as well as higher levels of recombination with increased 2n. A mathematical model shows that a Robertsonian fission of a single metacentric considerably increases haplotype diversity. This haplotype diversity may contribute to population adaptation to climatic stress and ecological unpredictability in space and time. The increase in diversity corroborates the nichewidth genetic-variation hypothesis.

Increased recombination frequencies resulting from directional selection for geotaxis in Drosophila

Abstract: Increased recombination frequencies resulting from directional selection for geotaxis in Drosophila

The predicament of masculinity: Towards understanding the male's experience of infertility treatments

Abstract: The commonsense notions that associate fertility and femininity are shared by the medical establishment, and have led to the concentration of research on women in the area of fertility. While feminist critics view this state of affairs as a consequence of male domination and emphasize women's predicament, this paper focuses on men's experience in this area. It is suggested that as research and treatment traditionally focus on the woman, therapies offered to the man are relatively scarce and his non-medical part in the process places him in a marginal position. The treatment entails embarrassment and anomie. The availability of sperm donation carries its own threat of men's dispensibility. A male-inspired association of procreation with women has led to the development of female-centered infertility therapies. As a consequence men have found themselves in a disadvantaged position.

The extraction of phrase structure during reading: Evidence from letter detection errors.

Abstract: In light of recent suggestions regarding the prominence of structure in speech production and comprehension, it has been postulated that structural processing might also play a similarly important role in reading Some evidence in support of this contention can be gleaned from eye-movement research However, more systematic support comes from recent work on letter detection during reading, which has shown that the rate of omission errors is inordinately high for morphemes that disclose phrase structure The results of three lines of research suggest that, early in text processing, readers attempt to extract a structural frame for the sentence to help the on-line integration of accessed representations, and that structure-supporting units recede to the background as the meaning of the sentence evolves

Production-Inventory Systems with Unreliable Machines

Abstract: A broad class of production-inventory systems is studied in which a number of producing machines are susceptible to failure following which they must be repaired to make them operative again. The machines' production can also be stopped deliberately due to stocking capacity limitations or any other relevant considerations. The interplay between the processes involved, namely, production, demand, and failure/repair or reliability, in conjunction with the shutdown policy used, determine the inventory accumulation process and possible shortages. We first obtain the stationary distribution of the inventory process for different assumptions on the random behavior of the production, demand, and reliability processes. By employing level-crossing techniques, a mathematical analysis is carried out for a "core" model, which then serves the role of the nucleus for the study of a wide range of models. We compute performance measures that characterize the operation of the production-inventory system with respect to its service-level to customers, expected inventory stocked, machines' utilization, repairmen utilization, and so on. A numerical illustration is provided which shows the effect of machine breakdowns on service and inventory levels.

Concepts of strategic commercial location: the case of container ports.

Abstract: A World that shrinks with progressive improvements in transportation and communications is a fact of 20th century life. The shrinking process can produce new patterns and perceptions of strategic location. In this paper we are looking specifically at nodes in transportaion system. In the ligth of transportation progress, we re-consider some of the time-worn ideas about centrality, accessibility, gateway locaations, junction, transit points, and the like. Do some of these notions become irrelevant in the modern transport age? Is it a questions f shifting geographical scale? Do we need more sophisticated concepts of strategic location? We suggest the answer ‘yes’ to all three questions. Our illustrations come from an examination of the world's top-ranked container ports. We give primary emphasis to the external geographical relationships of the ports, that is to situational aspects (not to say, however, that sitefeatures are inconsequetial). We are interested in the seaports users' —i.e., carriers and shipp...

Employee turnover in community mental health organization: A developmental stages study

Abstract: The purpose of this study was to examine the reasons for employee turnover in community mental-health residential services, and to determine the relationship of workers' developmental stage to those reasons. Three types of variables were collected in the study: 1) Demographics, including tenure and income; 2) Workers' ratings of their effectiveness, satisfaction, desired responsibility, expectancy of leaving the organization, morale, and competence; 3) Workers' ranking of the most important turnover factors for them, at the time of the study. Other personnel data was compiled by the organization for the use of this study. Significant findings were found in all interest areas of this study. The studied organization reached 50% yearly voluntary turnover, and 72% separation rate for the same year. Workers' stages of development found to have significant relationships with the choices workers would make in their selection of turnover factors. Workers in higher stages of development tended to choose "higher order" turnover factors like rewards and organizational factors. Nevertheless, the most significant factor in a decision to leave a CMH organization was low pay.

Rewards and organizational commitment across structural characteristics: a meta analysis

Abstract: This article uses meta-analysis to summarize previous empirical studies which examine the relationship between actual income/pay satisfaction and organizational commitment (OC) across different structural settings. Twenty-one studies with correlational data on the relationship between OC and income, and 27 studies dealing with OC and pay satisfaction are examined; these studies include 23 and 31 independent samples, respectively. The findings reveal a moderator effect related to type of occupation in the OC-income relationship, and to sector in the OC-pay satisfaction relationship. The findings also show the moderating effect of measurement of OC on pay satisfaction. Theoretical and methodological considerations pertaining to the OC-rewards relationship are discussed. Directions for future research and practical implications are indicated.

The diagonal multivariate natural exponential families and their classification

Abstract: A natural exponential family (NEF)F in ℝn,n>1, is said to be diagonal if there existn functions,a1,...,an, on some intervals of ℝ, such that the covariance matrixVF(m) ofF has diagonal (a1(m1),...,an(mn)), for allm=(m1,...,mn) in the mean domain ofF. The familyF is also said to be irreducible if it is not the product of two independent NEFs in ℝk and ℝn-k, for somek=1,...,n−1. This paper shows that there are only six types of irreducible diagonal NEFs in ℝn, that we call normal, Poisson, multinomial, negative multinomial, gamma, and hybrid. These types, with the exception of the latter two, correspond to distributions well established in the literature. This study is motivated by the following question: IfF is an NEF in ℝn, under what conditions is its projectionp(F) in ℝk, underp(x1,...,xn)∶=(x1,...,xk),k=1,...,n−1, still an NEF in ℝk? The answer turns out to be rather predictable. It is the case if, and only if, the principalk×k submatrix ofVF(m1,...,mn) does not depend on (mk+1,...,mn).

Is the future what it used to be? A behavioral theory of the decline of saving in the west

Abstract: In all but one (Austria) of the 24 OECD countries, all forms of saving—personal, business and government—expressed as a percent of income or GDP were lower in 1987 than in 1973. This decline in national saving—amounting to over 4% of GDP—implies a serious devaluation of the future among countries that comprise 60% of world output. No persuasive explanation or model has been advanced to explain it. This article proposes a behavioral theory, based on the proposition that for most households the marginal rate of time preference (the subjective premium attached to present consumption compared to future consumption), exceeds, rather than equals, market interest rates. This implies that it always pays to spend more by borrowing . People constrain themselves from doing so by a variety of self-imposed precommitment constraints. These constraints have been seriously weakened during the past 15 years by various forms of deregulation. It is argued that national saving will not recover until the pro-savings self-imposed constraints are restored, at least in part.

Kin and Nonkin under Collective Threat: Israeli Networks during the Gulf War

Abstract: T7his study presents a rare glimpse of how people use their social networks during a mortal threat. In surveys done around the time of the 1991 Gulf War, we asked residents of metropolitan Haifa, Israel, to tell us from whom they received support during the missile attacks. The results show that Israelis relied more on kin than they did in their everyday networks. However, how much they relied on kin varied by type of support, specifically by whether the help was the comfort and advice of conversation often provided by friends or was more immediate and direct aid overwhelmingly provided by kin. While we reinforce earlierfindings that people turn to kin in crises, we also show that nonkin provide a specific form of social support. Sociologists study personal social networks for a variety of reasons. Some analyze relations among individuals to identify social boundaries, others to understand how social relations might vary with structural conditions or historical eras. Yet others study how networks might help sustain physical and mental health. This article joins the strand of literature concerned with how interpersonal relations provide support during times of severe crisis. Among the common research questions are: Who seeks social support in an emergency? Who provides that support? How do the pattems of support in a crisis compare to those during everyday life? In this article, we add to the literature an unusual case study of network structure during a severe crisis: the rain of missiles upon Israeli civilians during the 1991 Gulf War. We report findings from a pair of surveys that asked respondents whom they turned to for support during the Iraqi missile attacks. * This study was funded by the Baruch Venger Fund at theHaifa and GalileeResearch Institute of the University of Haifa and by the Committee on Research, University of California, Berkeley. An earlier version of this article was presented at the annual meeting of theAmerican Sociological Association, August, 1992, Pittsburgh. Direct correspondence to Yossi Shavit, Department of SPS, Instituto Universitario Europeo, 50016 San Domenico di Fiesole (FI), Italy (shavit@datacomm.iue.it); or Claude S. Fischer, Department of Sociology, University of California, Berkeley, CA 94720 (fischer1@cmsa.berkeley.edu). ? The University of North Carolina Press Social Forces, June 1994, 72(4):1197-1215 This content downloaded from 157.55.39.170 on Sat, 23 Jul 2016 06:12:53 UTC All use subject to http://about.jstor.org/terms 11987/ Social Forces 72:4, June 1994 We fielded a preliminary survey in Haifa region during the last week of the war and the three weeks that followed. We also administered a revised and larger survey several months later. Specifically designed questions allow us to find out: (1) whom these Israelis turned to for emotional and practical exchanges during the war; (2) how those associates compared to the ones respondents typically turned to for more routine needs; and (3) which Israelis had more social support during the crisis and which had less support. This is, frankly, an opportunistic study, the major advantage of which is that it provides systematic data on social support for a representative sample of people during a real and severe crisis. The Gulf crisis was also the source of the study's major disadvantage: We could neither plan the research with sufficient lead time nor could we revise it in time to collect more data during the crisis. Both the onset and end of the war were out of the researchers' control.

The role of wholistic/configural properties versus global properties in visual form perception.

Abstract: A distinction has previously been proposed between global properties, defined by their position in the hierarchical structure of the stimulus, and wholistic/configural properties defined as a function of interrelations among component parts. The processing consequences of this distinction were examined in five experiments. In experiments 1-4 configural properties (closure and intersection) were pitted against component properties (line orientation and direction of curvature) and the results showed that discrimination and classification performance was dominated by the configural properties. In experiment 5 the relative perceptual dominance of type of property (configural/nonconfigural) and level of pattern structure (global/local) was examined. The results showed that classifications based on the configural property of closure were not affected at all by the level of globality at which this property varied. Global advantage was observed only with classifications based on line orientation. Taken together, the present results suggest that configural properties dominate discrimination and classification of visual forms, whereas the perceptual advantage of the global level of structure depends critically on the type of properties present at the global and local levels. These findings are also discussed in relation to findings on texture perception, and it is suggested that the perceptual system may be characterized by a predisposition for configural properties.

Building A Port Simulator

Abstract: The development of a simulation software for port operation is described, with special emphasis on considerations for choosing both software and hardware. These consider ations, along with input an...

Video home training (the Orion project): a short-term preventive and treatment intervention for families with young children.

Abstract: Developed in Holland and based on short-term, home-centered, filmed video feedback of family interactions, an experimental Orion project was conducted in Israel to determine whether it could be provided through local welfare departments as a routine treatment alternative. This article summarizes an evaluation of 52 families (with problems in parent-child interaction) and 64 control families that participated in the Orion Video Home-Training Project. Only the Orion families showed significant gains in all the eight areas of positive parent-child communication that are the focus of the program, which is based on reinforcing potential family strengths. These gains were generally sustained 6 months after program completion. There were several background variables, such as family status, income, health, education, and employment, that influenced the extent of family gains.