Showing papers by "Bar-Ilan University published in 1983"
TL;DR: In this article, the properties of the hydrogen bonds in liquid water were analyzed using the results of molecular dynamics simulations of the MCY-CI model and the connectivity of the clusters was analyzed in terms of the bridgeless polygons which are formed by the bonds.
Abstract: Equilibrium and dynamical properties of the hydrogen bonds in liquid water are analysed using the results of molecular dynamics simulations of the MCY-CI model. Properties of the hydrogen bond clusters as functions of temperature are described. The connectivity of the clusters is analysed in terms of the bridgeless polygons which are formed by the bonds. The problem of obtaining a meaningful definition of bond lifetime is discussed, and the results of lifetime measurements based on alternative definitions are shown.
529 citations
[...]
TL;DR: The notion of strongly G-graded rings was introduced by Dade as discussed by the authors, who showed that R × R → 1 is a group graded ring if and only if R1 is a crossed product R1 * G.
Abstract: Let R be a group graded ring . The map ( , ): R × R →1 defined by: (x,y) = (xy)1 , is an inner product on R. In this paper we investigate aspects of nondegeneracy of the product, which is a generalization of the notion of strongly G —graded rings,introduced by Dade. We show that various chain conditions are satisfied by R if and only if they are satisfied by R1 , and that when R1 is simple artinian, then R is a crossed product R1 * G. We give conditions for simple R-modules to be completely reducible R1 -modules . Finally, we prove an incomparability theorem,when G is finite abelian.
151 citations
Patent•
04 May 1983TL;DR: In this paper, individual living cells are placed at identifiable locations through the use of a carrier having a plurality of apertures which are arranged in an ordered array, and sized to hold individual cells.
Abstract: Individual living cells are placed at identifiable locations through the use of a carrier having a plurality of apertures which are 1) arranged in an ordered array, and 2) sized to hold individual cells. Once in the apertures, the cells can be studied, examined or manipulated on a one-by-one basis.
134 citations
TL;DR: This article investigated a model used by non-mathematically oriented students in solving problems in descriptive statistics and found that most students were able to acquire the appropriate schema of statistical concepts by engaging in diagnostic activities embedded within a feedback-corrective procedure.
Abstract: The present study investigated a model used by non-mathematically oriented students in solving problems in descriptive statistics. Analyses show that college students mistakenly assume that a set of means together with simple mean computation constitutes a mathematical group satisfying the four axioms of closure, associativity, identity, and inverse. This set of misconceptions is so deeply ingrained in a students' underlying knowledge base that mere exposure to a more advanced course in statistics is not sufficient to overcome those misconceptions. However, results of an experiment indicated that most students were able to acquire the appropriate schema of statistical concepts by engaging in diagnostic activities embedded within a feedback-corrective procedure.
129 citations
TL;DR: The results in this paper indicate that the borderline between decidable and undecidable propositional dynamic Logic (PDL) is extremely close to the original regular PDL, and the versions of PDL which are show to be beyond this borderline are shown to be actually very highly Undecidable.
98 citations
TL;DR: Patterns of lateral preferences of hand, eye and foot were analyzed on 7364 children, differing in race (black and white) and sex, and the effects seemed to be considerably stronger for hand and foot than for eye preferences.
Abstract: Patterns of lateral preferences of hand, eye and foot were analyzed on 7364 children, differing in race (black and white) and sex. Right hand and foot preferences were found in over 80%, and right eye preferences were found in over 50% of the subjects. No sex or race differences appeared in left-right preferences. However, significantly more females than males, and more blacks than whites, showed variable foot preference. Further analyses of cross preferences indicated that about 40% of the subjects showed consistent lateral preferences of hand, eye, and foot (about 37% right, and about 3% left), whereas the other 60% were divided among ten groups of different preference combinations. The three lateral measures were correlated to differing degrees. The data were interpreted as showing the effects of cerebral dominance on lateral preferences of hand, eye and foot. The effects seemed to be considerably stronger for hand and foot than for eye preferences. Due to a lack of supporting data, interpretation of r...
80 citations
TL;DR: A synergistic killing effect of HPD, light, and penicillin (10 μg/ml) on Staphylococcus aureus was demonstrated, although the bacteria were originally resistant to 100 μg/ mlPenicillin, and none of these effects was observed on Gram-negative bacteria.
Abstract: The photodynamic effect of hematoporphyrin derivative (HPD) on the viability of penicillin-resistantStaphylococcus aureus is described. Growth rate of the bacteria was markedly reduced by exposure to light and HPD.Staphylococcus viability was decreased by 80% in 3 h of growth even at low HPD concentration (12 μg/ml). A synergistic killing effect of HPD, light, and penicillin (10 μg/ml) onStaphylococcus aureus was demonstrated, although the bacteria were originally resistant to 100 μg/ml penicillin. A residual viability of only 3% was found by growth in medium containing this drug combination. The surviving bacteria after 3 h of treatment were sensitive even to 1 μg penicillin/ml. The mechanism of HPD action onStaphylococcus is composed of two steps: i) penetration of HPD into the bacterial cell, which may be accomplished in the dark with no harm to the cells; ii) damaging of the bacterial cell upon photoactivation. The photoactivated HPD completely inhibited thymidine incorporation into the bacterial DNA. This effect was accompanied by inhibition of RNA and protein synthesis, which was parallel in extent to the reduction in growth rate. Electron microscopic examination ofS. aureus exposed for 3 h to HPD and light showed the appearance of well-developed mesosomes in the bacterial cells. None of these effects was observed on Gram-negative bacteria.
72 citations
TL;DR: In this article, a Ca2+-activated ATPase was found in the same membrane vesicles which had a V max of 1.5 μmol/mg protein per h at free Ca 2+ concentration of 10 μM.
68 citations
TL;DR: Aplysia fasciata attempt to bite and swallow food wrapped in a plastic net, tasting food through holes in the net as mentioned in this paper, but the food cannot be swallowed, and becomes cyclically stuck and pushed out of the buccal cavity.
66 citations
TL;DR: In this article, the authors examined the impact of second requests on the percentage of donors and on donation size and found that foot-in-the-door paradigm alone alone enhanced donors' willingness to donate and that donation size can also be elevated by requesting specified amounts.
Abstract: This study examines the impact of second requests on the percentage of donors and on donation size. In the initial stage of the study, half of the subjects were asked to sign a petition for the establishment of a social club for the handicapped. The second stage was conducted on the National Collection Day for the Rehabilitation of the Mentally Handicapped. Petition signers were asked to donate either an amount of money of their own discretion or a predetermined amount (£40,50, or 60) requested by the canvasser. While the foot-in-the-door paradigm alone enhanced the percentage of donors, the present study indicates that donation size can also be elevated by requesting specified amounts.
60 citations
TL;DR: In this article, a scaling analysis of Monte Carlo simulations of random walks on percolation clusters was performed and the average diffusion constant was described by a single scaling function in which the crossover from an algebraic decay (in time) near ${p}_{c}$ to the asymptotic behavior above or below it occurs at time
Abstract: A scaling analysis is performed on Monte Carlo simulations of random walks on percolation clusters both above and below the threshold ${p}_{c}$. The average diffusion constant is described by a single scaling function in which the crossover from an algebraic decay (in time) near ${p}_{c}$ to the asymptotic behavior above or below it occurs at time ${t}_{\mathrm{cross}}\ensuremath{\propto}{|p\ensuremath{-}{p}_{c}|}^{\ensuremath{-}(2\ensuremath{
u}\ensuremath{-}\ensuremath{\beta}+\ensuremath{\mu})}$. The value of the percolation conductivity exponent $\ensuremath{\mu}$ is found to be 1.05 \ifmmode\pm\else\textpm\fi{}0.05 for two-dimensional systems and 1.5 \ifmmode\pm\else\textpm\fi{}0.1 for three dimensions.
TL;DR: Activity patterns of Aplysia fasciata were observed in a protected port environment and in an aquarium; major activities were feeding and mating, which collectively took up about 45% of the total time of the animals.
Posted Content•
TL;DR: In this paper, nonwmmetric Shapley values for coalitional form games with transferable utility were studied and axiomatically it is shown that two families of solutions of this type are possible.
Abstract: Nonwmmetric Shapley values for coalitional form games with transferable utility are studied. The nonsymmetries are modeled through nonsymmetric weight systems defined on the players of the games. It is shown axiomatically that two families of solutions of this type are possible. These families are strongly related to each other through the duality relationship on games. While the first family lends itself to applications of nonsymmetric revenue sharing problems the second family is suitable for applications of cost allocation problems. The intersection of these two families consists essentially of the symmetric Shapley value. These families are also char- acterized by a prObabilistic arrival time to the game approach. It is also demonstrated that lack of symmetries may arise naturally when players in a game represent nonequal size constituencies.
TL;DR: In this paper, it was shown that certain automorphism groups of algebraic varieties, and even schemes, are residually finite and virtually torsion free (a group virtually has a property if some subgroup of finite index has it).
Abstract: We show first that certain automorphism groups of algebraic varieties, and even schemes, are residually finite and virtually torsion free (A group virtually has a property if some subgroup of finite index has it) The rest of the paper is devoted to a study of the groups of automorphisms Aut(Γ) and outer automorphisms Out(Γ) of a finitely generated group Γ, by using the finite-dimensional representations of Γ This is an old idea (cf the discussion of Magnus in [11]) In particular the classes of semi-simplen-dimensional representations of Γ are parametrized by an algebraic varietySn(Γ) on which Out(Γ) acts We can apply the above results to this action and sometimes conclude that Out(Γ) is residually finite and virtually torsion free This is true, for example, when Γ is a free group, or a surface group In the latter case Out(Γ) is a “mapping class group”
TL;DR: In this article, the importance of ground state destabilization as the origin of the enhanced reactivity of α-nucleophiles is examined and it is concluded that, in general, this factor will contribute only slightly, if at all, to the manifestation of α effects.
TL;DR: Lipoxygenase activity was extracted from the mitochondrial fraction of baker's yeast and was purified by affinity chromatography on a linoleyl aminoethyl sepharose column and the second enzyme eluted was characterized as a true lipoxygen enzyme.
TL;DR: La procedure psychometrique mesure quatre facteurs: attirance pour la vie, repulsion pour the vies, attirances pour la mort, repulsive pour the mort.
Abstract: Etude controlee des attitudes envers la vie et la mort des enfants suicidaires. La procedure psychometrique mesure quatre facteurs: attirance pour la vie, repulsion pour la vie, attirance pour la mort, repulsion pour la mort. L'intensite de ces attitudes a ete mesuree a l'aide des reponses quantitatives des enfants aux questions qui ont suivi la narration de contes de fees, chaque conte representant une des quatre attitudes
TL;DR: In this article, a method based on fractal dimensionality was proposed for self-avoiding walks, and numerical results were obtained for 2, 3, 4, and 5 dimensions and were shown to be in excellent agreement with the prediction of the n=0 vector model.
Abstract: Corrections to scaling, as well as the critical exponent $\ensuremath{
u}$, are calculated for self-avoiding walks, with the use of a new highly accurate method based on fractal dimensionality. Numerical results are obtained for 2, 3, 4, and 5 dimensions and are shown to be in excellent agreement with the prediction of the $n=0$ vector model.
TL;DR: Results showed that the women in the high stress environment displayed significantly higher systolic and diastolic blood pressure, both during the relatively calm period and the period of the Yom Kippur War, than women who lived in the low stress environment.
Abstract: The present research examined the effects of living in an area which had been a target of terrorist activities for a long period, as well as the effects of war, on blood pressure of pregnant women For this purpose, the blood pressures of 5804 Israeli pregnant women, who gave birth between July 1973 and June 1975 and who had lived in either high, medium or low military stress environments were compared Blood pressures that were measured immediately before delivery were taken from the delivery record of the pregnant women in the hospital Results showed that the women in the high stress environment displayed significantly higher systolic and diastolic blood pressure, both during the relatively calm period and the period of the Yom Kippur War, than women who lived in the low stress environment Women who lived in the medium stress area were in between these two groups War increased the blood pressure in all three environments, but the increase in blood pressure from the calm period to the war period was greater in the high and medium stress environments than in the low stress environment Results further showed that the younger women displayed greater increase in the systolic blood pressure than the older women This finding was attributed to the fact that the husbands of the younger women serve in the front lines to a greater extent, which probably induces a higher level of anxiety
TL;DR: In this article, a group of women employed under a flexible working time schedule was compared with a group from the same organization under a rigid (fixed) schedule, with respect to overall work satisfaction, strain reactions and absenteeism rates.
Abstract: A group of women employed under a flexible working time schedule was compared with a group of women from the same organization employed under a rigid (fixed) schedule, with respect to overall work satisfaction, strain reactions and absenteeism rates. Marital status and parenthood were used as moderator variables. Neither main effects nor significant moderator effects were found for the individual outcomes as criteria. Absenteeism rates were significantly lower under the flexible than the rigid work schedule and married women and mothers had the lowest rates of absenteeism when employed under a flexible schedule.
TL;DR: Plasma membrane isolated from frozen ejaculated bull spermatozoa were found to contain calcium transport activity and the Ca+ uptake was inhibited by low concentrations of quercetin, which is known to be an inhibitor of (Ca2+ + Mg2+)-ATPase in many systems.
TL;DR: This work investigates the applicability of these two shifting algorithms to max-min and min-max partitioning of a tree for various different weighting functions, and defines the families of basic and invariantWeighting functions.
TL;DR: A method of analyzing subgroups of mental retardates for proportions of cases caused by nongenetic brain damage is presented here and applied to 490 Israeli retardates.
Abstract: A method of analyzing subgroups of mental retardates for proportions of cases caused by nongenetic brain damage is presented here and applied to 490 Israeli retardates. Among mild retardates in simplex and multiplex families with normal unrelated parents, most of the cases were caused by nongenetic brain damage and only a minority were caused by polygenic heredity. Among severe retardates in multiplex families with normal unrelated parents, nongenetic brain damage is probably a more important cause than is homozygosity. In all groups except two (mild retardates with normal consanguineous parents, and severe retardates with retarded parents) the contribution of nongenetic brain damage was surprisingly large.
TL;DR: Some systematic cross-sectional empirical results on density gradients and their determinants in various cities in Israel confirm findings of other studies regarding the relevance and importance of variables representing city size income and transportation costs and provide evidence as to the importance of land supply and age of city.
Abstract: Presents some systematic cross-sectional empirical results on density gradients and their determinants in various cities in Israel. To achieve this goal a two-stage estimation procedure is utilized. In the first stage using the 1972 Census of Population density gradients are estimated for all cities in Israel for which sufficient observations were available. The estimates obtained are used in a second stage to form two dependent variables which are then explained by variables such as income transportation costs city size tightness of land market and age of city. The results confirm findings of other studies regarding the relevance and importance of variables representing city size income and transportation costs they also provide evidence as to the importance of land supply and age of city. (authors)
TL;DR: Although decision time to words is significantly shorter with right hemifield stimulation than with left hemIField stimulation, decisionTime to non-words is the same whether they are presented to the right or left hem ifield.
TL;DR: In this article, a review of studies in Israel relating to attitudes of various ethnic, cultural and religious groups towards the disabled were reviewed. And the results indicate that although there were differences in attitudes towards disabled, these differences appear to be a function of interaction effects between many other variables and not necessarily only related to ethnic, culture, and religious affiliation.
TL;DR: ELL was computed for several countries in 1964 and the results were then compared with computations based on other development indicators, and found to give the same social welfare as the actual distribution of deaths by age.
TL;DR: The Kingdom of Tonga is unusual not only in its high level of literacy but also in the fact that the literacy is in large measure in the vernacular language as discussed by the authors.
Abstract: The Kingdom of Tonga is unusual not only in its high level of literacy but also in the fact that the literacy is in large measure in the vernacular language. Written Tongan is used for religious, governmental, informational, commercial, and personal functions: written English for external relations, higher level administration, and education. While the educational system is encouraging the learning of English, it is maintaining emphasis on the Tongan language.