Showing papers by "Ben-Gurion University of the Negev published in 1986"

Screening for depression in stroke patients: the reliability and validity of the Center for Epidemiologic Studies Depression Scale.

Abstract: This study examined the inter-observer reliability and validity of the Center for Epidemiologic Studies Depression Scale (CES-D) as a measure of depressive symptomatology in stroke patients, and its utility as a screening tool for depression in this population. The CES-D Scale is a brief questionnaire originally designed for use in community surveys. Twenty-seven non-aphasic patients enrolled in the Stroke Data Bank at the University of Maryland were interviewed by a research nurse using the CES-D. On the same day, each patient was independently evaluated by a research assistant using a psychiatric battery for depression and measures of cognitive, physical, and social functioning. Forty-one percent (11/27) of the patients were depressed according to clinical criteria for major or minor depression. With a cutpoint corresponding to the upper (most severe) 20% in community surveys, the CES-D Scale picked up 73% (8/11) of the depressed patients. In this sample no nondepressed patient scored over 16 on the CES-D (no false positives). The CES-D Scale scores correlated significantly with the other depression measures (r = .57 to r = .82, p less than .002) and did not correlate with the measures of cognitive, physical, or social functioning. Based on 24 patients who received a CES-D Scale score from both the nurse and the research assistant, inter-rater reliability was high (r = .76, p less than .001). Thus, the CES-D was found to be reliable and valid as a screening tool for assessing depression in stroke patients.

On the continuous limit for a system of classical spins

Abstract: The continuum limit of a cubic latice of classical spins processing in the magnetic field created by their closest neighbours is considered. Results concerning existence, uniqueness and (for initially small spin deviation) long time behaviour, are presented.

Digit span, reading rate, and linguistic relativity.

Abstract: The relations between reading time and memory span were studied in four languages: English, Spanish, Hebrew, and Arabic. Reading rate was measured either in speeded reading of digits or in normal-pace reading of stories. Faster speeded reading and normal-pace reading rates for a given language were associated with larger memory span for speakers of that language. These relations, which were shown to be monotonically related to the number of syllables or phonemes per item, extend the within-language word-length effect reported by Baddeley, Thomson and Buchanan (1975), across languages. In addition, these findings demonstrate a form of linguistic relativity: a relation between simple surface-structural features of language (number of syllables) and cognitive processing (memory span and reading rate). It is argued that this linguistic relativity may be limited by trade-offs between surface features and common linguistic practice.

Air-lift reactor analysis: Interrelationships between riser, downcomer, and gas-liquid separator behavior, including gas recirculation effects

Abstract: An approach to air-lift reactor analysis is presented that examines the three parts of the air-lift—the riser, downcomer, and gas-liquid separator—as three interconnected and interrelated elements. Downcomer flow configurations are described and characterized by either straight or oscillating bubble flow patterns. The downcomer gas flow rate is determined using a two-sparger system, and a correlation is presented relating the downcomer superficial gas velocity to the downcomer gas holdup. Gas recirculation is calculated and related to the geometric and operating conditions of the gas-liquid separator. It is shown that an increase in residence time in the gas-liquid separator decreases the gas recirculation rate. Correlations are presented relating gas holdup and liquid velocities to superficial gas velocity. A sparger was added near the entrance of the downcomer, in addition to the conventional placement near the entrance of the riser. Results of such a two-sparger system are discussed in relation to reactor stability and liquid velocities.

Quantification of thalamocortical synapses with spiny stellate neurons in layer IV of mouse somatosensory cortex

Abstract: The distribution of thalamocortical (TC) and other synapses involving spiny stellate neurons in layer IV of the barrel region of mouse primary somatosensory cortex (SmI) was examined in seven male CD/1 mice. TC axon terminals were labeled by lesion-induced degeneration, which has been shown to label reliably all TC synapses in mouse barrel cortex. Spiny stellate neurons, labeled by Golgi impregnation and gold toning, were identified with the light microscope prior to thin sectioning and electron microscopy. Analysis of eight dendritic segments from seven spiny stellate neurons showed that most of their synapses are with their dendritic spines, rather than with their shafts. Axospinous synapses are primarily of the asymmetrical type, whereas axodendritic synapses are mainly of the symmetrical type. Dendrites of spiny stellate neurons consistently form thalamocortical synapses, most of which involve spine heads rather than spine stalks or dendritic shafts. From 10.4% to 22.9% of all asymmetrical synapses with dendrites of spiny stellate neurons involve TC axon terminals. In general, this is a higher range than the ranges that characterize the TC synaptic connectivity of dendrites belonging to other types of neurons, implying that spiny stellate neurons are perhaps more strongly influenced by TC synaptic input than other types of cortical neurons examined previously. Spines involved in TC synapses were distributed irregularly along each of the stellate cell dendrites; about half of the interspinous intervals between these spines were about 5 microns or less. Modulations of the efficacy of TC synaptic input to dendrites of layer IV spiny stellate neurons are discussed in the light of recently reported computer simulated analyses of axospinous synaptic connections.

Constraints and field equations for ten-dimensional super Yang-Mills theory

Abstract: We give a complete proof of the equivalence between constraint equations and field equations for thed=10,N=1 supersymmetric Yang-Mills theory, a result proposed and partially proved recently by Witten [1]. Our approach explicitly reconstructs the superconnection satisfying the constraints from the on shell component fields. A key ingredient of the method is the choice of a suitable family of gauges, effectively eliminating all gauge dependence on anti-commuting co-ordinates. As a corollary, obtained by dimensional reduction, we also deduce the equivalence of constraints and field equations for thed=4,N=4 theory, as well as ford=6,N=2.

Salt balance of leaves of the mangrove Avicennia marina

Abstract: The contribution of each of the salt-transporting processes to the NaCl balance of the leaves of the salt-recreting mangrove Avicennia marina (Forssk.) Vierh. was quantitatively investigated. Transpiration rates, xylem sap concentration, leaf salt content, recretion rates and rates of salt retranslocation out of the leaves were continuously monitored during three day periods and the salt fluxes in and out of the leaves were calculated. The results indicated that salt filtration by the roots is by far the most important salt-rejecting mechanism, preventing some 80% of the salt which is carried towards the root surface by the transpiration stream, from entering the shoot. Out of the remaining quantity of salts which enter the root xylem and reach the leaves, only 40% is removed by the salt-recreting glands.

Proper stable Bezout factorizations and feedback control of linear time-delay systems†

Abstract: This paper deals with the existence and construction of proper stable Bezout factorizations of transfer function matrices of linear time-invariant systems with commensurate time delays. Existence of factorizations is characterized in terms of spectral controllability (or spectral observability)of the co-canonical (or canonical) realization of the transfer function matrix. An explicit procedure for computing proper stable Bezout factorizations is given in terms of a specialized ring of pure and distributed time delays. This procedure is utilized to construct finite-dimensional stabilizing compensators and to construct feedback systems which assign the characteristic polynomial of the closed-loop system.

Misconceptualization of the chemical equilibrium concept as revealed by different evaluation methods

Abstract: Three evaluation methods were applied to examine students’ mastery of the ‘chemical equilibrium’ concept: (i) a school achievement test, (ii) a misconception test specifically designed to pinpoint possible misconceptions regarding eight central features (ideas) of the chemical equilibrium concept, and (iii) the free sorting of 18 concepts related to chemical equilibrium that served as a tool for cognitive structure mapping. An attempt was made to correlate the information derived from these methods. Students’ performance on the misconception test was poorer than on school tests. It was found that low achievements on the misconception test are reflected in the latent categories of the free sorting of the appropriate group. The reflection is judged by comparing the latent categories derived from the free sorting to theoretical groupings based on the relatedness of the 18 concepts to the eight features. The combination of the data from the evaluative methods can serve to provide teachers with useful informat...

Leukocytosis in non hematological malignancies--a possible tumor-associated marker.

Abstract: Leukocytosis (WBC counts 10,000/mm3) was detected in 77 out of 252 patients (30%) with ten different types of nonhematological malignancy (NHM) at the time of diagnosis. A full search including serological and bacteriological screening was performed to exclude other possible causes of leukocytosis. Among the different tumors, carcinomas of the lung and colorectum were the most prevalently associated with leukocytosis. Absolute monocytosis was found in 25% of the patients and absolute eosinophilia in only 4.8%. The leukocytosis was attributed mainly to an increase in the mature polymorphonuclears, suggesting a release mechanism of WBC from storage pools by factors secreted or induced by the tumor. Neither the age nor the sex of the patients affected the incidence or magnitude of leukocytosis. However, the presence of metastases was associated with a significantly higher incidence of leukocytosis (p<0.05). The associated leukocytosis may be regarded as a poor prognostic sign, and was associated with a significantly (p<0.007) shorter survival time. In contrast, absolute lymphocytosis may have a positive effect on the survival time (p=0.01). Tumor-associated leukocytosis may be an additional tumor-associated marker, of value in assessing and monitoring patients with NHMs.

Increase in rat intestinal permeability to endotoxin during hyperthermia.

Abstract: Victims of heat stroke exhibit several clinical features which are also encountered in endotoxaemia. In order to investigate these similarities hyperthermic rats were used to explore the possibility that high body temperature results in increased permeability of intestinal wall to endotoxin. 125I endotoxin was introduced into intestinal segments taken from non-heat exposed rats. The segments were then incubated at 37‡ C or 45‡ C. Intestinal segments from heat stressed rats were similarly prepared and incubated at 37‡ C. Leakage of endotoxin from segments taken from heat stressed rats was three times greater than from those from non-heat stressed rats, as were the segments from non-heat stressed rats which were incubated at 45‡ C. These results indicate that the intestinal membrane is damaged by heat and that an increase in outward leakage of microbial endotoxins from the gut then occurs. This might contribute to the pathophysiological picture of heatstroke.

Numerical solution of constrained non‐linear algebraic equations

Abstract: On discute la solution numerique de n equations algebriques non lineaires a n inconnues avec des contraintes sur les variables, en operant une distinction entre les contraintes physiques et absolues. On utilise la methode de prolongement ou des fonctions de penalite dans le premier cas et la methode de Newton a pas reduit pour les problemes a contraintes absolues

Interobserver agreement in the diagnosis of stroke type.

Abstract: • Interobserver agreement is essential to the reliability of clinical data from cooperative studies and provides the foundation for applying research results to clinical practice. In the Stroke Data Bank, a large cooperative study of stroke, we sought to establish the reliability of a key aspect of stroke diagnosis: the mechanism of stroke. Seventeen patients were evaluated by six neurologists. Interobserver agreement was measured when diagnosis was based on patient history and neurologic examination only, as well as when it was based on results of a completed workup, including a computed tomographic scan. Initial clinical impressions, based solely on history and one neurologic examination, were fairly reliable in establishing the mechanism of stroke (ie, distinguishing among infarcts, subarachnoid hemorrhages, and parenchymatous hemorrhages). Classification into one of nine stroke subtypes was substantially reliable when diagnoses were based on a completed workup. Compared with previous findings for the same physicians and patients, the diagnosis of stroke type was generally more reliable than individual signs and symptoms. These results suggest that multicentered studies can rely on the independent diagnostic choices of several physicians when common definitions are employed and data from a completed workup are available. Furthermore, reliability may be less for individual measurements such as signs or symptoms than for more-complex judgments such as diagnoses.

The detection of a common idiotype of anti-DNA antibodies in the sera of patients with monoclonal gammopathies

Abstract: The sera of 265 patients with monoclonal gammopathies were examined for the presence of a dominant idiotype of the anti-DNA antibody [16/6 idiotype (Id)] and for anti-DNA activity An enzyme-linked immunosorbent assay (ELISA) with a rabbit anti-16/6 antibody revealed 23 (87%) sera that contained increased concentrations of the idiotype Seven of the patients had benign monoclonal gammopathy, three multiple myeloma, three Waldenstrom macroglobulinemia, five essential mixed cryoglobulinemia, and five monoclonal cryoglobulinema In 5 of the 23 sera, antinuclear activity was also noted In 11 of the 16/6 Id-positive sera the anti-nucleic acid antibody reactions were found to be polyspecific, reacting with polydeoxythymidilic acid and polyinosinic acid, in addition to single-stranded DNA and double-stranded DNA Similar results were achieved with the purified serum monoclonal components The specificity of the idiotype analysis was demonstrated with an unrelated dominant idiotype of anti-HBsAg antibody In none of the patients, except one (with essential mixed cryoglobulinemia), was lupus symptomatology noted

The role of mallard ducks (Anas platyrhynchos) in distribution and germination of seeds of the submerged hydrophyteNajas marina L.

Abstract: The effect of passage ofNajas marina L. seeds through the digestive system of the common mallard duck (Anas platyrhynchos) on their germinability was investigated. Most of the seeds (∼70%), which were consumed by the birds were digested. However, germination of the remaining seeds was remarkably improved. Germination of seeds whose seed coats were mechanically cracked was also higher than that of the controls and equalled the germination percentage of the mallard-treated seeds. Seeds ofNajas are retained in the diegestive tracts of mallards for over 10 hours. Thus, as mallards are strong flyers, the seeds ofNajas may be distributed over long distances.

Actions of Commutative Hopf Algebras

Abstract: We show that actions of finite-dimensional semisimple commutative Hopf algebras H on //-module algebras A are essentially group-gradings. Moreover we show that the centralizer of H in the smash product A # H equals A\" ® H. Using these we invoke results about group graded algebras and results about centralizers of separable subalgebras to give connections between the ideal structure of A, A and A # H. Examples of the above occur naturally when one considers: (1) finite abelian groups G of automorphisms of an algebra A with | G |~ e A; (2) G-graded algebras, for finite groups G; (3) finite-dimensional restricted Lie algebras L, with semisimple restricted enveloping algebra u(L), acting as derivations on an algebra A.