Showing papers by "Ben-Gurion University of the Negev published in 1983"
TL;DR: Combined salbutamol-dexamethasone treatment resulted in more than twice the rate of improvement of the other treatments, and a potentiating effect of corticosteroids on the beta-adrenergic responsiveness is a possible explanation for this combined treatment in the management of acute wheezing in infancy.
Abstract: Thirty-two infants, aged 1 to 12 months, hospitalized with acute wheezing, were studied. They were randomly divided into four treatment groups of eight patients each. The treatments were intramuscular dexamethasone or placebo (double-blind), and salbutamol (oral and inhaled), or none (open), in all four possible combinations. The study was carried out as a randomized block design with eight blocks of four infants each, matched by age and clinical score. Average daily improvements, as reflected by changes in the clinical score and length of hospital stay, was essentially the same for infants treated with placebo, salbutamol alone, and dexamethasone alone. However, combined salbutamol-dexamethasone treatment resulted in more than twice the rate of improvement of the other treatments. The difference was statistically highly significant (P less than .01). Furthermore, the response of this combined treatment was observed within 24 hours; none of the ten infants in whom there was no significant improvement within 48 hours and neither of the two patients who developed respiratory failure received the combined salbutamol-dexamethasone treatment. A potentiating effect of corticosteroids on the beta-adrenergic responsiveness is a possible explanation for the advantage of this combined treatment in the management of acute wheezing in infancy.
264 citations
TL;DR: In this paper, the authors found that winds coming from two basically different directions at different times and striking the dune obliquely were responsible for sand transport and erosion or deposition along the lee flank.
Abstract: Field measurements were made on a longitudinal dune in the Sinai Desert in order to understand its morphology and dynamics. The field measurements contradicted the wind structure indicated by the helicoidal flow theory. Rather, it was found that winds coming from two basically different directions at different times and striking the dune obliquely were responsible for sand transport and erosion or deposition along the lee flank.
The essence of this mechanism is the deflection of the wind airflow on the lee flank of the dune to a direction parallel to the crest line. The occurrence of erosion or deposition depends upon the angle of incidence between the wind and the crest line. When this angle is 40°) the velocity of the deflected wind drops and deposition takes place on the lee flank.
The angle of incidence in each wind storm is changed intermittently between 30° and 100° along the dune because the dune meanders and because of the sinuous outline of the crest line. In this manner sand transport and erosion or deposition occurs along the lee flank depending on the angle of incidence between the wind and the crest line. As a result of the deflection of the wind the dune elongates at an average rate of more than 1 m per month. Peaks and saddles along the crest line advance at an average rate of 0.7 m per month.
The lack of uniformity in the effects of the wind on both sides of the dune creates a lack of uniformity in the rate of erosion and deposition. This can explain the formation of peaks along the crest line of the dune.
228 citations
TL;DR: In this paper, the authors consider whether separability or nonjointness is the better approach for attaining tractability for multicrop production function estimation, and demonstrate a proposed approach by way of example.
Abstract: This paper considers whether separability or nonjointness is the better approach for attaining tractability for multicrop production function estimation. Characteristics of agricultural production associated with allocated inputs, physical constraints, and output determination imply sufficient nonjointness for estimation, whereas separability is less plausible. The paper also addresses estimation of production functions with allocated inputs where allocations are not observed and demonstrates a proposed approach by way of example.
191 citations
TL;DR: In this article, it was shown that the light rare-earth elements (LREE) in major mineral species predict that these elements should behave incompatibly during crystallization and increase with fractionation.
180 citations
TL;DR: The phosphotransferase activity of the Rous sarcoma virus src gene product, pp60src, was inhibited both in vitro and in vivo by the bioflavonoid quercetin and studies in vitro showed that this flavonoid did not inhibit the phosphorylation of physiological substrates of this enzyme.
Abstract: The phosphotransferase activity of the Rous sarcoma virus src gene product, pp60src, was inhibited both in vitro and in vivo by the bioflavonoid quercetin. The Ki for the inhibitory effect was in the range of 6-11 microM under conditions in vitro. The inhibitory effect of quercetin was competitive towards the nucleotides ATP and GTP as substrates for pp60src and was non-competitive towards alpha-casein as the protein substrate of this kinase activity. In contrast, studies in vitro of the phosphotransferase activity of the catalytic subunit of the cAMP-dependent protein kinase showed that this flavonoid did not inhibit the phosphorylation of physiological substrates of this enzyme. In cultured cells the half-maximal inhibition of tyrosine phosphorylation of pp60src as well as the phosphorylation of the Mr = 34000 protein, a physiological substrate of pp60src, was in the range 0.06-0.08 mM.
175 citations
TL;DR: In the last few years additional experimental and theoretical studies that contribute to improved design and scaleup of trickle-bed reactors have been published as discussed by the authors, and the scope of this paper is to review critically these improvements.
Abstract: Fixed-bed, catalytic reactors in which gas and liquid phases flow concurrently downward, termed trickle beds, are becoming more widely used in chemical processing, particularly in the petrochemical industry. Shah (1979) has summarized the advantages of trickle-bed reactors and mentioned some of the processes in which the reactors are used. Shah's monograph and earlier reviews (Satterfield, 1975; Goto et al., 1977; Hofmann, 1978; Gianetto et al., 1978) have discussed factors affecting reactor performance.
In the last few years additional experimental and theoretical studies that contribute to improved design and scaleup of trickle-bed reactors have been published. The scope of this paper is to review critically these improvements. Progress in understanding local rates of reaction is considered first. Then recent developments in reactor design are analyzed.
158 citations
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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
TL;DR: It was found that patterns of granivory in the Israeli deserts are very similar to those reported for the same groups in the deserts of North America.
Abstract: Utilization of non-native seeds by seed-eating rodents and ants was studied experimentally in the field. It was found that patterns of granivory in the Israeli deserts are very similar to those reported for the same groups in the deserts of North America. Rodents are more efficient than ants at finding and harvesting seeds. Only rodents can find and harvest seeds that occur below the soil surface.
146 citations
TL;DR: It is shown that the imbalance in H‐ 2Kb to H‐2Db is correlated with metastatic properties of a given clone, but local tumor growth is not, and support for this notion of imbalance is found in experiments on MHC modulation by interferon and retinoic acid.
Abstract: Imbalance in the Kb and Db region encoded molecules is observed in Lewis lung carcinoma clones. The uncloned metastatic population and the D122 high-metastatic clone show no expression of H-2Kb products, while the nonmetastatic A9 clone expresses Kb products. Twenty-nine new subclones of 3LL and A9 were analyzed for D-end and K-end membrane expression, primary growth rate and metastatic spread. We show that the imbalance in H-2Kb to H-2Db is correlated with metastatic properties of a given clone, but local tumor growth is not. A "low Kb/low Db" phenotype is nonmetastatic as is a "high Kb/high Db" phenotype; a "low Kb/high Db" is highly metastatic and a "medium Kb/high Db" is moderately metastatic. We find support for this notion of imbalance in experiments on MHC modulation by interferon and retinoic acid. Interferon increases both Kb and Db expression of A9 and D122 clones yet the net increase of Db was greater than Kb. This was associated with an increase in metastasis formation. Retinoic acid increases the expression of the Db gene product on the nonmetastatic A9, clone, without apparent changes in Kb expression. This treatment shifts the A9 to a high-metastatic phenotype. The significance of this imbalance to the tumor--host relationship is discussed.
130 citations
TL;DR: It is suggested that in order to produce the usual priming effect, the primes have to be processed for meaning rather than probed for constituents.
Abstract: The semantic relationship between a prime and a target word has been shown to affect the speed at which the target word is processed This series of experiments investigated how the semantic priming effect is influenced by the nature of the task performed on the prime word Subjects were asked to perform either a naming or a letter-search task on the prime word and either a lexical-decision or color-naming task on the target word When the primes were named, response times for the target words were facilitated in the lexical-decision task and inhibited in the color-naming task However, these effects were eliminated or reduced to an insignificant level when the primes were searched for letters We suggest that in order to produce the usual priming effect, the primes have to be processed for meaning rather than probed for constituents
118 citations
TL;DR: In this article, the authors modified and improved Silver's algorithm for the joint replenishment problem, and extensive experimentation showed that the errors of the algorithm can be reduced by an order of magnitude.
Abstract: Silver's algorithm for the joint replenishment problem is modified and improved. Computational requirements due to this modification are relatively very small. Extensive experimentation shows that the errors of Silver's algorithm can, on the average, be reduced by an order of magnitude.
TL;DR: In this article, three strip transects, each ca 100 contiguous 0.5 × 1 m2 quadrats, were sampled during the spring bloom of March 1981 across four surface structural units of a Negev Desert research watershed at Sede Boqer, Israel.
Abstract: Three strip transects, each ca 100 contiguous 0.5 × 1 m2 quadrats, were sampled during the spring bloom of March 1981 across four surface structural units of a Negev Desert research watershed at Sede Boqer, Israel. Presence of all vascular plants was recorded. Data were subjected to detrended correspondence analysis (DCA ordination), and resulting spatial patterns of species distribution and abundance were compared. Large-scale gradients of vegetation were related to differences in soil moisture availability among the four structural units. Where micro-scale vegetation patterns were important, these correlated with rock and crevice microtopography. Species richness was influenced by high numbers of therophytes on the dry upper slope of the watershed and their reduced importance on the lower three units. Relationships between vegetational patterns and known ecosystem properties of the watershed are discussed.
TL;DR: The influence of forward scattering on heterodyne receiver performance is investigated, taking into account turbulence and it is shown that the SNR is improved when the ratio of the scattering particulate size to turbulence coherence diameter decreases.
Abstract: Both scattering and turbulence can effect the spatial coherence of short wavelength signals propagating through the open atmosphere. In this paper, the influence of forward scattering on heterodyne receiver performance is investigated, taking into account turbulence. It is shown that the effect of forward scattering is to reduce the effective heterodyne receiver area through spatial coherence degradation. A common approach to scattering as an attenuation phenomenon is not always valid. Generally, this approach underestimates the SNR. The accuracy of the attenuation approach depends on the ratio R of the actual receiver diameter to the scattering particle diameter. If R > 100, scattering is essentially large angle and the typical treatment of scattering as an attenuation effect is indeed justified. However, for small R, forward scattering is primarily small angle, field coherence is noticeably affected by forward scattering, and the attenuation approach is not valid. Further, it is shown that the SNR is improved when the ratio of the scattering particulate size to turbulence coherence diameter decreases. From the practical point of view, the most important result of this study is that small receivers use their area more effectively than large receivers. Thus, an array of several small receivers may perform better than one large receiver with the same total area. The treatment here is particularly relevant for coherent detection through clouds, fog, precipitation, and turbid media in general, including liquid media.
TL;DR: In this article, the authors used information theory and signal detection theory techniques to assess the validity of police reported traffic accident data and found that the most reliable reported data were those concerned with the accident location, date, and number of drivers, passengers, and vehicles.
TL;DR: In this article, the understanding of economics of 89 Israeli children, aged 7-17, was probed by means of interviews and questionnaires, including commerce, production, strikes, capital investment, and the causes of inflation.
TL;DR: In this paper, the authors conducted hydrological and geological investigations carried out during the last ten years in the deserts of the Sinai and the Negev, and found that unique climatological conditions prevailed between ca. 100,000 and ca. 10,000 yr B.P. The uniqueness was expressed by the following characteristics: 1) Higher precipitation and recharge rates caused the Nubian Sandstone aquifers to be filled up through the outcrops in central Sinai and to overflow through big springs emerging along the faults of the Syrian-African rift system.
TL;DR: In this paper, a theoretical model is developed to determine optimal pesticide use under increasing pesticide resistance, compared to the laissez-faire solution and to the centralized solution with incomplete information about pesticide resistance.
TL;DR: In this article, a detailed study of symmetric transfer functions is presented, and a detailed analysis of transfer functions can be found in Section 5.1.1]...
TL;DR: A digital image is approximate as a sum of outer products dxyT where d is a real number but the vectors x and y have elements +1, -1, or 0 only and the expansion gives a least squares approximation.
Abstract: We approximate a digital image as a sum of outer products dxyTwhere d is a real number but the vectors x and y have elements +1, -1, or 0 only. The expansion gives a least squares approximation. Work is proportional to the number of pixels; reconstruction involves only additions.
TL;DR: The significance of skin evaporation in body temperature regulation of heat-stressed birds is discussed.
TL;DR: In winter, there was an inverse relationship in the pond between the population density of Spirulina and the extent of contamination by Chlorella sp.
Abstract: The effects of sodium bicarbonate concentration, population density, and temperature on the maintenance of an outdoor monoculture of the cyanobacterium Spirulina platensis were studied. A clear response by Spirulina to the concentration of bicarbonate was evident, with 0.2M bicarbonate representing the lowest concentration in which a monoculture could be maintained. When the temperatures fell during the winter period to some 20-25/sup 0/C below the optimum for Spirulina. Chlorella sp. gradually increased and became the dominant species in the culture. Raising the temperature by covering the pond with transparent polyethylene resulted in a sharp decline in the population of Chlorella, and a gradual resumption of species dominance by Spirulina. In winter, there was an inverse relationship in the pond between the population density of Spirulina and the extent of contamination by Chlorella sp., but no such effect was observed under field conditions at temperatures higher than 25/sup 0/C.
TL;DR: In this article, the authors consider the non-Born-Oppenheimer effect on the symmetry of a molecule in excited or ionic states compared to the neutral ground state and show that the symmetry lowering can have several important consequences, including a distortion of the molecular framework, leading to a lowering of the symmetry.
Abstract: The various electronic states in which molecules can exist are often considered to be independent. In this article we turn our attention to the limitations of this assumption, namely the interaction between different electronic states through the nuclear motion. This interaction can have several important consequences, two of which are discussed in some detail. One is a distortion of the molecular framework, leading to a lowering of the symmetry of a molecule in excited or ionic states compared to the neutral ground state. General aspects of this symmetry lowering are outlined and interpreted with the aid of typical examples. The other consequence considered is the ability of the nuclei to “jump” between different molecular potential energy surfaces (non-Born-Oppenheimer effects). The nature of this behavior is analyzed and it is argued that the “jumping” can be very fast and efficient, dominating completely the nuclear motion. To exemplify our general ideas we refer to the photoelectron spectra of ethylene and related compounds and demonstrate that they are governed by strong non-Born-Oppenheimer effects. It emerges that the Franck-Condon principle fails in the analysis of their vibronic structure.
TL;DR: It is proposed that repair of a deviated nasal septum be further evaluated as a mode of therapy for this condition because of its simplicity and low rate of complication.
TL;DR: A generic extension where there are no Aronszajn trees of height ω 2 or ω 3 is provided and it is shown that some large cardinal assumptions are necessary for such a consistency result.
TL;DR: Sign recall levels ranged from 3 to 6% during the day and from 14 to 18% at night, and other variables that were measured (sign content, roadway environments, and subjective levels of fatigue and boredom) had no significant effects on sign registration.
Abstract: Drivers were stopped 200 m after passing a warning sign and were tested for recall and recognition of the sign. It was predicted that at night, when the view of the road ahead is severely restricted, sign registration levels would be higher than during the day, when drivers can obtain most of their information directly from their view of the road ahead. The results supported this hypothesis; sign recall levels ranged from 3 to 6% during the day and from 14 to 18% at night. Other variables that were measured (sign content, roadway environments, and subjective levels of fatigue and boredom) had no significant effects on sign registration.
TL;DR: In this article, the authors describe the wind tunnel modeling of echo and climbing dunes, and show that these self-accumulated dunes are found in front of, or behind, topographic obstacles such as cliffs, shrubs, and boulders.
Abstract: Publisher Summary This chapter describes the wind tunnel modeling of echo and climbing dunes. Eolian sand dunes originate as accretions of sand on existing sand patches, and may develop independent of fixed surface features. It is found that apart from these self-accumulated dunes, sand accumulations are found in front of, or behind, topographic obstacles such as cliffs, shrubs, and boulders. The data concerning the formation of echo and climbing dunes gathered during wind tunnel tests made on several simulated cliffs with different inclinations is presented in the chapter. Three types of measurements were taken, including the modeling of echo and climbing dunes in front of simulated cliffs, tracing of eddies and wind turbulence in front of the simulated cliffs and over echo dune models and through a bubble generator, and measurements of wind velocity (with a hot-wire anemometer) in front of the simulated cliffs and over the echo dune models. It is observed that when echo dune models built of wood were placed in front of the simulated cliff with shape and position similar to those modeled with sand the bubbles showed constant and prominent reverse-flow eddies between the dune and the cliff.
TL;DR: In this article, the predictions of several entanglement models of rubber elasticity for the uniaxial stress-strain response of crosslinked polymer networks are examined, and it is found that the Gaylord tube model and the Flory constrained junction fluctuation model both agree well with the experimental data.
TL;DR: This study proposes a model for the spatial (3-dimensional) and temporal distribution of the skin temperature during and following a radiation pulse, and shows a significant difference between the temperature of the surface of theskin and that of the border between the epidermis and the dermis, which is the location of the most superficial receptive nerve ends.