Showing papers by "Tel Aviv University published in 1971"

The effects of extrinsic incentive on some qualitative aspects of task performance1

Abstract: Summary Thirty two subjects of high school age were tested under two experimental conditions on a variety of tasks. Subjects in the extrinsic-incentive condition were promised a reward for their participation in the experiment No mention of reward was made in the no-incentive condition. Consistent with die experimental hypothesis, it was found that subjects in the latter as opposed to the former condition exhibited superiority in creativity of performance and task recall. In addition, they manifested a stronger Zeigarnik effect, and reported greater enjoyment of the experiment The data were discussed in reference to the idea that the degree of intrinsic motivation for a task is determined by the actor's self-attributed cause for its performance

S and P States of the Helium Isoelectronic Sequence up to Z = 10

Abstract: Calculations have been made of the energy levels and other properties of the states $n^{1}S$, $n^{3}S$, $n^{1}P$, and $n^{3}P$, $n=2 \mathrm{to} 5$, for atoms belonging to the helium isoelectronic sequence up to $Z=10$, and also for the higher excited $S$ states of helium. The theoretical term values, including the contributions from the mass-polarization correction and the relativistic effects of order ${\ensuremath{\alpha}}^{2}$ are listed. A detailed comparison with the experimentally determined energy differences between $S$ and $P$ states for He I up to F VIII shows a satisfactory agreement in almost every case, provided that we include an estimate of the Lamb-shift correction to the $S$-state energy level when considering transitions involving the $1^{1}S$, $2^{1}S$, or $2^{3}S$ states.

Heat flow in regular and disordered harmonic chains

Abstract: We investigate the steady state heat flux J in a large harmonic crystal containing different masses whose ends are in contact with heat baths at different temperatures. Calling ΔT the temperature difference and L the distance between the ends, we are interested in the behavior of J/ΔT as L→∞. For a perfectly periodic harmonic crystal, J/ΔT approaches a fixed positive value as L→∞ corresponding to an infinite heat conductivity. We show that this will be true also for a general one‐dimensional harmonic chain (arbitrary distribution of different masses) if the spectral measure of the infinite chain contains an absolutely continuous part. We also show that for an infinite chain containing two different masses, the cumulative frequency distribution is continuous and that the spectrum is not exhausted by a denumerable number of points, i.e., the spectrum cannot consist entirely of point eigenvalues with a denumerable number of limit points. Using a theorem of Matsuda and Ishii, we show that for a random chain, ...

Ecology and distribution of the benthic fauna in the shallow waters of the Red Sea

Abstract: Approximately 500 animal species and plants are listed as being the most typical for the infratidal and shallow subtidal benthic fauna of the Red Sea. Most of them are divided into communities typical for various soft and hard substrata, and at different water depths. The oceanographic conditions and the development of several of the communities are discussed in general terms.

Individual differences in attention and the prediction of flight criteria.

Abstract: A dichotic listening test was constructed which requires S to monitor a relevant message and to ignore a concurrent message presented to the other ear. The test has promising validity for predicting different criteria of proficiency in flying high-performance aircraft. An analysis of the most valid type of errors suggests that a change in an existing orientation is accompanied by a transient instability of selective attention. Most errors in continuous attention are omissions, which indicate a failure of the listening set. Intrusions, which indicate a failure of selectivity, are rare and their frequency is not correlated to flight criteria.

f VALUES FOR TRANSITIONS BETWEEN THE LOW-LYING S AND P STATES OF THE HELIUM ISOELECTRONIC SEQUENCE UP TO Z = 10.

Abstract: $f$ values have been computed for the transitions $m^{1}S\ensuremath{-}n^{1}P$, $m=1\ensuremath{-}5$, $n=2\ensuremath{-}5$ and $m^{3}S\ensuremath{-}n^{3}P$, $m,n=2\ensuremath{-}5$ for members of the helium isoelectronic sequence up to $Z=10$. The agreement between the results obtained using the dipole length, and velocity formulas, together with the convergence of the results as an increasing number of terms are included in the expansions of the wave functions, indicate that the values obtained are accurate to within 1% or better for the large majority of the transitions.

Twenty-five years later: A limited study of the sequelae of the concentration camp experience

Abstract: The central question raised is: To what extent does maladaptation and malfunctioning characterize survivors of the unimaginably extreme, prolonged trauma of the Nazi concentration camps, and to what extent do we find successful adaptation among such persons? The extensive literature on camp survivors is largely incapable of confronting this question. Even when not based only on a small number of patients in psychiatric treatment, most papers deal with select populations. Moreover, it is seldom that survivors are compared to appropriate controls. - A study which included Israeli women aged 45–54 of Central European birth and focused on problems of adaptation to climacterium provided data relevant to the central question. The respondents constituted a representative sample of all women in a middle-sized Israeli city meeting the criteria of age and nativity. Of the 287 women in the sample, 77 had been in a Nazi concentration camp during World War II. The remaining 210 women were used as a control group. - Adaptation was measured from several different points of view: menopausal symptomatology, the subjective sense of wellbeing, physical and emotional health status, and role satisfaction. The detailed data show camp survivors to be more poorly-adjusted than the controls. - Of greater import, however, is the fact that a not-inconsiderable number of concentration camp survivors were found to be well-adapted, despite the extreme trauma. It is suggested that this finding requires serious investigation. Three complementary explanations of the fact of successful adaptation are proposed: an initial underlying strength, a subsequent environment which provided opportunities to reestablish a satisfying and meaningful existence, and a “hardening” process which allow the survivor to view current stresses with some equanimity.”

Postnatal changes in some red cell parameters.

Abstract: Summary The red blood picture was studied in detail from birth to 12 weeks. The low point in the red cell count was reached in the seventh week, which represented the turning point from a negative to a positive balance between cell production and destruction. From the dynamics of the total number of circulating red cells it was concluded that, although erythropoiesis slows down after birth, a considerable amount of red cell production takes place during the first few postnatal weeks. The MCHC increased significantly over the first 5–6 postnatal weeks and remained constant thereafter. Macrocytes predominated at birth. Their percentage distribution decreased after the second week with a corresponding increase in microcytes. The red cell density distribution curve in the neonatal period is sigmoid in shape. The range of densities is, however, wider than in the adult. The curve shifts gradually to the heavy side from birth to 5 weeks, while from 5 to 12 weeks a shift back to the light side is observed. Macrocytes preponderate in the light fractions.

Abscisic Acid Raises the Permeability of Plant Cells to Water

Abstract: A number of recent observations have indicated a role for abscisic acid in maintaining water balance. Treatment with ABA reduces the transpiration rate (3, 5), probably by bringing about stomatal closure (2, 4). Furthermore, water stress leads to a significant increase in ABA concentration in leaves (5, 7). On the other hand, ABA increases the rate of root exudation (6). The present communication reports a marked effect ofABA on the permeability of plant tissues to water. The effect is observable both on Lp, the coefficient of hydraulic conductivity, and on Pd, the coefficient of diffusional permeability to water. The effect on hydraulic conductivity was detected in experiments in which osmotic water flux between cells and medium was followed with time. The equations for net osmotic flux into or out of cells can be written as follows:

Studies on ribonucleic acid synthesis in the venom glands of Vipera palaestinae (Ophidia, Reptilia).

Abstract: RNA metabolism in the venom glands of Vipera palaestinae was studied at different stages after manual extraction of the venom (milking). The rate of 32P incorporation into gland RNA was found to be maximal at 1–4 days after milking in correlation with the height of the secretory epithelium. Venom production attained a maximum only after 8–16 days, in parallel with the accumulation of stable species of cellular RNA.

Growth Rate of Escherichia coli at Elevated Temperatures: Limitation by Methionine

Abstract: When Escherichia coli growing in minimal medium is shifted from 37 C to any temperature in the range 40 to 45 C, the growth rate immediately assumes a new, lower value, characteristic of that temperature. The decrease is shown to be due, in several strains, to decreased activity of the first enzyme of the methionine pathway, homoserine trans-succinylase, which thus appears to be more heat-sensitive than any other essential enzyme in the cell. This sensitivity does not involve progressive denaturation of the enzyme; rather, the response to a shift of temperature, in either direction, is immediate and reversible.

Bilateral spontaneous and simultaneous rupture of the quadriceps tendons in gout

Abstract: 1. A case of bilateral spontaneous and simultaneous rupture of the quadriceps tendons is described. 2. The underlying cause was found to be gouty affection of the tendons. 3. So far as is known, a similar case has not previously been recorded.

Transmission and Reflection of Plane Waves at an Elastic-Viscoelastic Interface

Abstract: Summary The reflected and transmitted waves due to an elastic plane sinusoidal P or SV wave impinging on the plane interface between an elastic and a linearly viscoelastic medium are found analytically for any type of viscoelastic behaviour. The properties of these waves depend both on the frequency of the incident wave and the angle of incidence of the impinging wave. Some general properties of the transmitted waves are that both the dilatational and equivoluminal waves in the viscoelastic media have refraction angles less than 90°, the displacement trajectories of material points in the viscoelastic media are ellipses, and the waves attenuate with increasing distance from the interface.

Studies ON MUTUALISTIC SYMBIOSIS BETWEEN SYCONIA AND SYCOPHILOUS WASPS IN MONOECIOUS FIGS

Abstract: Summary The constituents of a normal monoecious fig, namely the male and female flowers, the short-and long-styled female flowers and the male and female wasp galls, are arranged in definite spatial and numerical relations. The normal development of the syconium depends on a balance of these different elements. Occasionally various types of aberrant figs are found in nature, differing from normal figs in development and in final structure. These are purely gall figs, seed figs and male wasp or female wasp figs. Such abnormal figs were obtained experimentally by introducing specially treated female wasps into receptive young syconia at the receptive B phase. Treatments of the wasps involved one of the following: shortening of their ovipositor, preventing contact of wasps with pollen, preventing wasp fertilization or their sterilization by irradiation with gamma rays at various doses. In some of the already inhabited figs, the wasp larvae were killed by insecticidal sprays. Analysis of the development and structure of naturally-found aberrant syconia, taking into account also the conditions under which they may be produced experimentally, provides data for elucidating various aspects of the mutualistic symbiosis in figs.

The Zealots: the Case for Revaluation

Abstract: Two events have conspired to redirect the attention of scholars towards the Zealots, who played so decisive a part in the Jewish rebellion against Rome between A.D. 66 and 73: the discovery of the Judaean Desert manuscripts, and the total excavation of Masada (1955–56; 1964–65). Both events have cast new light on the Zealot movement, but, as is so often the case with new discoveries, they have also created new problems, and neither can furnish a substitute for the careful examination of, and reflection upon, the character and origins of the movement. The important material has for long been available to scholars. Despite this, agreement has been rare. However conscientious historians have wished to be, they have tended to be influenced by the traditions to which they are the heirs. Denounced by their enemies in the ancient world, the Zealots, it may be thought, have also been exposed to subtler misunderstandings on the part of modern historians.

Corrected transposition of the great arteries: A modified approach to the clinical diagnosis in 30 cases

Abstract: A simplified approach to the diagnosis of corrected transposition of the great arteries is proposed. Patients are divided into 3 groups —those without obstruction to pulmonary blood flow, those with obstruction to pulmonary blood flow and those without associated defects—each presenting a uniform clinical, electrocardiographic and roentgenographic picture. Patients without obstruction to pulmonary blood flow had the clinical findings of a large ventricular septal defect with pulmonary hypertension and a large, predominant left to right shunt. Observations in patients with corrected transposition of the great arteries and with obstruction to pulmonary blood flow clinically resembled those of patients who had a large ventricular septal defect with pulmonic stenosis and a predominant right to left shunt. A case of corrected transposition of the great arteries without associated defects is reported. A review of reports of similar cases revealed that the majority had insufficiency of the left atrioventricular valve or atrioventricular block, or both; very few cases without these latter anomalies were reported. We believe that this group of patients also has distinctive clinical, electrocardiographic and roentgenographic findings.

The Effect of Epidermal Cell Water Potential on Stomatal Response to Illumination of Leaf Discs of Vicia faba

Abstract: Illuminated leaf discs of Vicia faba were brought into equilibrium with a series of mannitol solutions. The width of stomatal aperture and the osmotic potential of guard cells and epidermal cells were determined. It was found that the maximal aperture was obtained when epidermal cells were at about incipient plasmolysis and that any increase in their turgor pressure brought about a decrease in stomatal aperture. These findings emphasize the importance of epidermal cells in determining the width of the stomatal pore.

Mechanism of passive Q switching in CO 2 lasers

Abstract: Passive Q switching of a CO 2 laser by saturable absorbers is analyzed in terms of a four-state kinetic model previously used to interpret infrared saturations double resonance, and pulse transmission. Good agreement is found between the predictions of this model and the experimental dependence of such variables as pulsewidth, repetition frequency, and peak power on the presence of buffer gases mixed in with the absorber.

Sequences of Precopulatory Behavior of the Jackal (Canis Aureus L.)

Abstract: The present paper presents a first order description of the precopulatory behavior of the golden jackal (Canis aureus syriacus) without using emotionally-toned words. The coarse structure of this behavior which extends over 4 months prior to copulation is described. During this time, jackals roam the fields in pairs, each pair in a particular area. From time to time they perform certain series of actions while circling each other in a specific manner. The term "T-sequence" is used for this behavior which might be defined as precopulatory. A detailed fine-grain description of selected actual sequences of four captive pairs and three wild pairs is presented. Common features and variation in performance, with special emphasis on the latter, are summarized. Precopulatory behavior of jackals might be viewed as a complex of three groups of events superimposed on one another: the group of events which constitute the T-sequences (such as circling, standing perpendicularly to the mate, putting the head on the mate's back, etc.) is superimposed on a group of patterns which are performed during the first phase of precopulatory behavior - sniffing the ground, urination and scraping. Later, a third group of patterns is superimposed on the first two groups: this group includes the male licking the female's vulva, the female mounting the male and other patterns. At this stage, the frequency of appearance of patterns of the first two groups decreases gradually; the male starts to mount the female, and a few days later copulations follow. Variation in performance was found in the following acts: 1) In certain pairs the male always forms the top of the T during T-sequences, in others the female, and in still other pairs both mates take turns at forming either the top or the base of the T. Relative body position during T-sequences is in correlation with the distribution of events between the mates. It also affects the time of onset of the week of copulations. 2) Some "agonistic" patterns were observed during T-sequences only in captivity. 3) Certain behavior patterns are performed by some pairs but not by others. 4) Some behavior patterns are performed in different "styles" by different individuals. The performance of T-sequences is related to the following factors: a) sequential relation of events to copulation, b) time of day, c) change in environment, d) howling, e) duration of pair bond, f) individual differences. Motivational models as well as quantitative analysis were avoided, since the variability of the material calls for the development of special methods for fine-grain analysis. This material deserves phenomenological treatment, in the sense that regularity should be looked for first in the structure of concrete specific behavior sequences, and only then in the behavior in general.