Showing papers by "University of Haifa published in 1984"
01 Jan 1984
TL;DR: The evolutionary significance of genetic diversity of proteins in nature remains controversial despite the numerous protein studies conducted electrophoretically during the last two decades.
Abstract: The evolutionary significance of genetic diversity of proteins in nature remains controversial despite the numerous protein studies conducted electrophoretically during the last two decades. Ironically, the discovery of extensive protein polymorphisms in nature (reviewed by Lewontin, 1974; Powell, 1975; Selander, 1976; Nevo 1978, 1983b; Hamrick et al., 1979; Nelson and Hedgecock, 1980), did not resolve the disagreement between the die ho torn ou s explanatory models of selection (e.g., Ayala, 1977; Milkman, 1978; Clarke, 1979; Wills, 1981) versus neutrality (Kimura, 1968; Kimura and Chta, 1971; Nei, 1975; and modifications in Kimura, 1979atb). The more general problem of the relative importance of the evolutionary forces interacting in genetic population differentiation at the molecular levels of proteins and DNA, i.e., mutation, migration, natural selection and genetic drift, remains now as enigmatic as ever.
735 citations
TL;DR: In this article, an empirical description and discussion of interstate conflict behavior is presented. The basis is a recently completed data set consisting of all recorded instances of threats, displays, and displays.
Abstract: This article offers an empirical description and discussion of interstate conflict behavior. The basis is a recently completed data set consisting of all recorded instances of threats, displays, an...
459 citations
TL;DR: Thirteen biochemical groups of wild mice from Europe, Asia, and Africa belonging to the genus Mus are analyzed at 22–42 protein loci and Phylogenetic trees are proposed and patterns of biochemical evolution are discussed.
Abstract: Thirteen biochemical groups of wild mice from Europe, Asia, and Africa belonging to the genus Mus are analyzed at 22–42 protein loci. Phylogenetic trees are proposed and patterns of biochemical evolution are discussed, as well as the possible contribution of wild mice to the genetic diversity of laboratory stocks.
296 citations
TL;DR: In this article, the stability of producer cooperatives in market economies is analyzed in a dynamic context, and it is shown that, when permitted to hire wage laborers, a producer cooperative, even if its labor productivity is higher than in an otherwise equivalent capitalist firm, is likely to lose its cooperative character because members' personal income will be maximized when “expensive” members are replaced by “inexpensive” wage-laborers.
190 citations
TL;DR: In this article, an optimal auditing scheme for the tax authorities who face a given tax and penalty functions and a given budget constraint is proposed, where individuals can be classified into one of three groups and each group is characterized by two parameters: (i) the probability of being audited in that group, and (ii) into which group will an individual move if: (ii.a) he reported truthfully, (iii) he cheated.
188 citations
TL;DR: In this paper, an analysis of the flow sediment hysteresis shape may assist in determining the sediment source area in a small basin, where sediment is derived from the bed and banks of the channel or areas adjacent to the channel.
Abstract: Summary Analysis of the flow sediment hysteresis shape may assist in determining the sediment source area in a small basin. A clockwise hysteresis occurs when sediment is derived from the bed and banks of the channel or areas adjacent to the channel, whereas an anti-clockwise hysteresis occurs when the upper part of the slopes is the sediment source area.
182 citations
TL;DR: The results, which demonstrate that in mammals (at least in the mole rat, as in nonmammalian vertebrates), nonocular photoreceptors exist, suggest that the mechanism by which mammals integrate photoperiodic changes is not the same when the animals are transferred from long to shortphotoperiod as when transferred from short to longPhotoperiod.
Abstract: The involvement of the Harderian gland, atrophied eyes, and melatonin in the perception of photoperiodic changes has been studied in the mole rat, a fossorial blind mammal the thermoregulatory capacity of which is photoperiod-dependent. When transferred from a long photoperiod to a short one, mole rats increase their resistance to cold, a perfectly reversible phenomenon. After 2 weeks under short photoperiod the thermoregulatory capacities of animals without Harderian glands are less than those of the controls. The Harderian gland appears thus to be implicated in the detection of photoperiodic changes. After 5 weeks, however, the Harderianectomized animals had perfectly integrated the photoperiodic change, so demonstrating that other photoreceptor organs exist. The atrophied eyes, which, under these conditions, do not seem to play an important role, are involved when the animals are transferred from short photoperiod to long photoperiod. Melatonin, but not 5-methoxytryptamine, appears to be a crucial compound in such a phenomenon. These results, which demonstrate that in mammals (at least in the mole rat, as in nonmammalian vertebrates), nonocular photoreceptors exist, suggest that the mechanism by which mammals integrate photoperiodic changes is not the same when the animals are transferred from long to short photoperiod as when transferred from short photoperiod to long photoperiod.
114 citations
TL;DR: An ethnobotanical survey was conducted in Israel on native plants which are known as medicinal plants by different ethnic groups practicing traditional medicine, and 43 species are reported, based on quotations and frequency of utilization.
109 citations
TL;DR: It is shown that the multivariate random variables possess many of the properties of univariate phase type distributions and derives explicit formulas for various probabilistic quantities of interest.
Abstract: A univariate random variable is said to be of phase type if it can be represented as the time until absorption in a finite state absorbing Markov chain. Univariate phase type random variables are useful because they arise from processes that are often encountered in applications, they have densities that can be written in a closed form, they possess some useful closure properties, and they can approximate any nonnegative random variable. This paper introduces and discusses several extensions to the multivariate case. It shows that the multivariate random variables possess many of the properties of univariate phase type distributions and derives explicit formulas for various probabilistic quantities of interest. Some examples are included.
106 citations
TL;DR: It is suggested that mercury selection is operating in nature on allozyme genotypes of these marine organisms along patterns comparable with those found previously in laboratory experiments and that the enzymes studied here display an adaptive pattern in polluted environments.
Abstract: The geographic distributions of mercury-tolerant allozyme genotypes of the enzyme phosphoglucomutase in the shrimp Palaemon elegans and the enzyme phosphoglucose isomerase in the marine gastropod Monodonta turbinata were compared in a mercury-polluted site versus several unpolluted sites on the Israeli coast of the Mediterranean sea. We conclude that in both phosphoglucomutase and phosphoglucose isomerase, the level of the mercury-tolerant allozyme genotypes was higher in the polluted as compared with the unpolluted sites. These results suggest that mercury selection is operating in nature on allozyme genotypes of these marine organisms along patterns comparable with those found previously in laboratory experiments. We suggest that the enzymes studied here display an adaptive pattern in polluted environments. Therefore, they may be used as potential indicators and monitors of marine pollution.
96 citations
TL;DR: In this paper, it was shown that the Jacobson radical of a finitely generated p.i.d. algebra is nil-potent, i.e., it is not polynomial.
TL;DR: It is concluded that natural populations of wild emmer wheat in Israel vary not only in genetic polymorphisms of allozymes and disease resistance, but also in quantitative traits of agronomic importance that should be conserved and utilized in wheat crop improvement.
Abstract: Populations of wild emmer wheat, Triticum dicoccoides, in Israel, originating from diverse habitats, and tested earlier for allozyme (Nevo et al., 1982) and disease resistance polymorphisms (Moseman et al., 1983a, 1983b; Nevo et al., 1984a, 1984b), were compared and contrasted for performance in agronomically important phenotypic traits. The traits compared involved 10 variables comparing germination, earliness, biomass and yield variables. The field experiments were conducted in 1980, 1981 and 1982 in two relatively standardized and contrasting environments: mesic (Mount Carmel, Haifa) and xeric (Acedat Farm, and Sede Boqer, in the northern Negev desert). The experimental design involved 12 population quadrangles at Avedat Farm in 1980, and rows of randomized genotypes of five populations in both Haifa and Sede Boqer in 1981 and 1982. The results indicate that the characters studied are partly genetically determined. Striking genetic variation was found between and, at least in some characters, also within populations in each site, whereas remarkable environmental variation including genetic-environmental interaction was found between the mesic and the xeric sites. We conclude that natural populations of wild emmer wheat in Israel vary not only in genetic polymorphisms of allozymes and disease resistance, but also in quantitative traits of agronomic importance. These traits are economically significant and should be conserved and utilized in wheat crop improvement.
TL;DR: The reactions indicated that the number of sources of resistance to E. graminis tritici which can be obtained from T. dicoccoides plants growing wild in Israel and elsewhere is almost unlimited, and plants should be collected at sites in ecological and geographic regions where those two species occupy optimum habitats and are exposed to the powdery mildew pathogens.
Abstract: The reactions of 233 Triticum dicoccoides acessions, collected at 10 sites in Israel and elsewhere, to infection with cultures of Erysiphe graminis tritici, were determined. The reactions indicated that the number of sources of resistance to E. graminis tritici which can be obtained from T. dicoccoides plants growing wild in Israel and elsewhere is almost unlimited. One hundred and fourteen or 49% of the accessions were resistant, and 137 or 59% of the accessions were resistant or moderately resistant to infection with four cultures of E. graminis tritici which possess the virulence genes corresponding to most of the identified resistance genes in wheat. Accessions collected at sites with marginal habitats where T. dicoccoides grows poorly and has lower grain weight, were more susceptible than were accessions collected at sites with an optimal habitat for growth of T. dicoccoides. The results agreed with those in a previous study with Hordeum spontaneum, and indicate that to obtain H. spontaneum or T. dicoccoides accessions with the highest level of resistance to the powdery mildew pathogens, plants should be collected at sites in ecological and geographic regions where those two species occupy optimum habitats and are exposed to the powdery mildew pathogens.
TL;DR: It is concluded that natural populations of wild barley in Israel vary not only in genetic polymorphisms of allozymes and disease resistance, but also in quantitative traits of agronomie importance that are economically significant and should be conserved and utilized in barley crop improvement.
Abstract: Populations of wild barley, Hordeum spontaneum, in Israel, originating from diverse habitats, and tested earlier for allozyme (Nevo et al., 1979a) and disease resistance polymorphisms (Moseman et al., 1984; Nevo et al., 1984a), were compared and contrasted for performance in agronomically important phenotypic traits. The traits compared involved 10 variables comparing germination, earliness, numerical and weight variables of biomass and yield. The field experiments were conducted in 1980, 1981 and 1982 in two relatively standardized and contrasting environments: mesic (Mount Carmel, Haifa) and xeric Avedat farm, and Sede Boqer (both in the northen Negev desert). The experimental design involved 26 population quadrangles at Avedat farm (1980), and rows of randomized plants of 11 populations in both Haifa and Sede Boqer (1981 and 1982).
TL;DR: Salinity in vivo induced a marked decrease in catalase and malate dehydrogenase activities, however, peroxidase in vivo showed an optimum curve of activity vs external NaCl concentration, with an optimum at ca 1 M NaCl.
Abstract: The effect of high NaCl concentrations on the activity of catalase (EC 1.11.1.6), peroxidase (EC 1.11.1.7) and malate dehydrogenase (NAD+-linked; EC 1.1.1.37) from leaves of Halimione portulacoides (L.) Aellen was studied. The plants were exposed to high salinity during growth and enzyme activity was measured either in the absence or in the presence of various concentrations of NaCl. Increasing salinity in vitro induced three types of effects: (1) an increase in activity (peroxidase); (2) a decrease in activity (catalase); (3) stimulation by low salt concentration but inhibition by higher concentrations (malate dehydrogenase). Salinity in vivo induced a marked decrease in catalase and malate dehydrogenase activities. However, peroxidase in vivo showed an optimum curve of activity vs external NaCl concentration, with an optimum at ca 1 M NaCl. Exposure of plants to salinity induced changes in the properties of the enzyme proteins: they precipitated at a higher (NH4)2SO4 concentration, were eluted later during Sephadex G-200 filtration, and showed a shift in the maximal, minimal and optimal temperatures. These data are interpreted as evidence for conformational changes in the enzymes due to prolonged exposure to high salinity stress; such changes could be disruption into monomers (catalase and malate dehydrogenase), or changes in molecular shape (in the peroxidase).
TL;DR: In this paper, a study was conducted to uncover young Israelis' perceptions of the American reality using the postulates and methodology of the cultivation analysis approach to mass communication, revealing that heavy viewers demonstrate a strong and consistent tendency to paint a rosier picture of life in the U.S., in terms of wealth and standard of living, even when other factors (age, gender, residence and ethnic group) are held constant.
TL;DR: The authors explored the relationship between dispute outcomes and international stability and found that dyadic and nation level outcomes are significantly related to the degree of subsequent stability, which is consistent with the expectation.
Abstract: This study attempts to explore the relationship between dispute outcomes and international stability. Stability is defined as a period characterized by the absence of violent-ridden or violent-prone interactions among states. Two models of international stability are discussed. The 'peace by empire' model posits that stability tends to increase following decisive victories and imposed settlements in which the victors subdue the losers. The 'prudence in victory' model contends that stability is enhanced following symmetrical outcomes in which the grievance of the parties toward the post-dispute status quo are minimized. A test of these models on a random sample of serious interstate disputes between 1816-1976 suggests that: a) Both nation level outcomes (i.e., the identity of the winners and losers) and dyadic level outcomes (i.e., the mode of resolution or non-resolution of the dispute) are significantly related to the degree of subsequent stability, b) This relationship is consistent with the expectation...
TL;DR: An inventory was constructed to assess risk takers' personality characteristics, enhance the understanding of risk taker's personality in general, and provide a tool for the selection of candidates as discussed by the authors.
Abstract: An inventory was constructed to assess risk takers' personality characteristics, enhance the understanding of risk takers' personality in general, and provide a tool for the selection of candidates...
TL;DR: On expose les faits fondamentaux de la theorie de bifurcation de Shelah et donne des preuves courtes and directes des proprietes de base and des equivalences entre les diverses definitions de bIfurcation.
TL;DR: The issue is examined in terms of the relative odds of the races for incumbency in a series of occupational groupings, and the effect of percentage black on race-linked occupational differentiation across 124 major American cities is analyzed.
Abstract: A large body of literature investigating the link between black percentage in the community and occupational differentiation, has found disparities to be greater in places where blacks are in a higher proportion. The present paper discusses first, theoretical perspectives and methodological techniques employed in past research; second, examines the issue in terms of the relative odds of the races for incumbency in a series of occupational groupings; and third, analyzes the effect of percentage black on race-linked occupational differentiation across 124 major American cities. Using log-linear procedures, blacks, relative to whites, are much more likely to be in unskilled and semiskilled manual occupations, while whites, relative to blacks, are far more likely to be in white-collar and upper-status positions. Moreover, blacks’ denial of access to higher-status positions, their channeling to lower-status work, and their ability to overflow into specific intermediate-status occupations are found to be greatly influenced both by percentage black as well as other community characteristics. The findings are discussed in light of sociological theories suggesting that the issue cannot be understood solely by the competition hypothesis. One must also consider the overflow and queuing explanations.
TL;DR: In this paper, sixth-grade pupils from both public and religious public schools were compared with regard to cognitive morality and actual moral behavior, and the results showed that the re...
Abstract: Sixth-grade pupils from secular public (V = 68) and religious public (V = 57) schools were compared with regard to cognitive morality and actual moral behavior. The results show that the re...
TL;DR: The results suggested that hyperactive and nonhyperactive first-grade children may have deficits in self-control skills.
Abstract: This study was aimed at evaluating the self-control behaviors of hyperactive (HA) and nonhyperactive ( NHA ) first-grade pupils under conditions of repeated failure on a previously learned concept formation task. Subjects were divided into HA and NHA groups on the basis of their scores on the Conners (1969) Teacher Rating Scale. During the training stage of the experiment the children learned a concept formation task under a schedule of contingent positive reinforcement. In the test stage they performed the same task but under a negative noncontingent reinforcement schedule. The results revealed no differences in initial rate of learning the task between the groups. After the introduction of the negative noncontingent reinforcement schedule, however, the HA group showed a marked decrease in the use of effective problem-solving strategies. The HA children's performance on the concept formation task was accompanied by the emission of negative self-evaluations and solution-irrelevant statements. The NHA group used significantly more statements showing useful goal-directed cognitive mediations than the HA children. The results suggested that HA children may have deficits in self-control skills.
TL;DR: Geological, geomorphological, and archeological data of changes in sea level during the Holocene at the Mediterranean coast of Dor provide a eustatic curve of the region that shows that sea level was approximately 2 meters below the present level 4000 years ago and was 1 meter higher than the presentlevel 1500 years ago.
Abstract: Geological, geomorphological, and archeological data of changes in sea level during the Holocene at the Mediterranean coast of Dor provide a eustatic curve of the region. This curve shows that sea level was approximately 2 meters below the present level 4000 years ago, rose to 1 meter below the present level 3000 years ago, and was 1 meter higher than the present level 1500 years ago. It then dropped to 1 meter below the present level about 800 years ago.
TL;DR: The location of these suspended sediments is consistent with computations of the maximum depth of wave stirring on the shelf as mentioned in this paper, and no changes in the longshore transport of sediment along the Israeli coast are anticipated from the Aswan Dam for a few hundred years.
Abstract: Sediment is being transported from the Nile Delta to the Israeli coast by a wave-induced longshore current carrying mainly sand, and by the geostrophic Mediterranean Current, detected in Earth Resources and Technology Satellite (ERTS) photographs through the presence of suspended sediments. The location of these suspended sediments is consistent with computations of the maximum depth of wave stirring on the shelf. Since the construction of the Aswan Dam in 1965, sand has been more than adequately supplied by the severe erosion of the Nile Delta beaches. No changes in the longshore transport of sediment along the Israeli coast are anticipated from the Aswan Dam for a few hundred years.
TL;DR: Novel mapping schemes for trees onto hexagonal arrays (or grids) and appropriate algorithms are proposed here and shown to be superior over known mappings on square arrays ( or grids).
Abstract: Tree structures have been proposed for special-purpose and general-purpose multiprocessors due to their desirable property of logarithmic path from the root to any leaf element. Since only local communication among processors is needed in tree structures, they are well suited for the VLSI technology. Such an implementation requires an area-economical mapping of a tree on a plane. Novel mapping schemes for trees onto hexagonal arrays (or grids) and appropriate algorithms are proposed here and shown to be superior over known mappings on square arrays (or grids).
TL;DR: The problem of finding a point in the intersection of a finite family of closed convex sets in the Euclidean space is considered in this article, where several iterative methods for its solution are reviewed and some connections between them are pointed out.
Abstract: The problem of finding a point in the intersection of a finite family of closed convex sets in the Euclidean space is considered here. Several iterative methods for its solution are reviewed and some connections between them are pointed out.
TL;DR: The primary sequences of the myoglobins of two rodents (the South American viscacha and the Mediterranean mole rat) have been determined and both myoglOBins exhibit one polymorphism.
Abstract: The primary sequences of the myoglobins of two rodents (the South American viscacha and the Mediterranean mole rat) have been determined. Both myoglobins exhibit one polymorphism. The two rodent sequences have been compared with each other and with other known myoglobins. The myoglobin of the viscacha is similar to those of the diving mammals and penguin in having a high arginine content. Among mammalian sequences, the arginines at positions 77 (in one of the viscacha myoglobins) and 79 have been found only in the myoglobin from viscacha. Mole rat myoglobin has a lysine at position 31, where arginine or serine is found in all other known vertebrate myoglobins.
TL;DR: The results show that both gerbils are adapted to arid environments and the difference in the thermoneutral zones of the two species is discussed in terms of its adaptive nature.
Abstract: Species of the genus Gerbillus are very common among the rodent fauna inhabiting arid zones and dune habitats in the palaearctic region. In Israel G. nanus is distributed in extreme arid areas, while G. allenbyi is common in coastal plain dune habitats, of mesic and semi-arid areas. Therefore, their distribution pattern is considered allopatric.Heat production, estimated by the oxygen consumption (Vo2), and body temperature (T b) at various ambient temperatures were measured in both gerbils. The thermoneutral zone for G. allenbyi is between T a=28-35° C ([Formula: see text] T b=36.3-38.3° C) and for G. nanus is at T a=33±1° C ([Formula: see text], T b=38.8° C). The [Formula: see text] values at thermoneutrality are 75.7% and 50.6% respectively of the calculated values for rodents with a mean body weight of 35.3 g and 28.4 g.Nonshivering thermogenesis (NST) was measured in both species as the maximal response to an injection of noradrenaline (2.0 mg/Kg s.c.). NST magnitude was the same for both species.The results show that both gerbils are adapted to arid environments. The difference in the thermoneutral zones of the two species is discussed in terms of its adaptive nature.