Showing papers by "Bar-Ilan University published in 1990"

Attachment styles and fear of personal death: A case study of affect regulation.

Abstract: The relation between attachment styles and fear of personal death was assessed. We classified a sample of Israeli undergraduate students into secure, ambivalent, and avoidant attachment groups and assessed the extent of, and the meaning attached to, overt fear of personal death as well as the extent of fear at a low level of awareness. Ambivalent subjects exhibited stronger overt fear of death than did secure and avoidant subjects, and both ambivalent and avoidant subjects showed stronger fear of death at a low level of awareness than secure subjects. Ambivalent subjects were also more likely to fear the loss of their social identity in death, and avoidant subjects were more likely to fear the unknown nature of their death. Results are discussed in terms of the effects of attachment styles on affect regulation. According to Bowiby's (1973) attachment theory, "when an individual is confident that an attachment figure will be available to him whenever he desires it, that person will be much less prone to either intense or chronic fear than will an individual who for any reason has no such confidence" (p. 202). Whereas most attachment research has focused on the fear of separation from a loved person, no attention has been paid to the fear of the ultimate separation: personal death. The purpose of the present study was to examine the relation between attachment styles and fear of personal death.

Investment in general training: the role of information and labour mobility*

Abstract: Following the seminal work of Becker (I964), it is widely accepted in the literature that firms will be unwilling to finance training which workers may use in other firms. This paper takes issue with this prediction and suggests that firms will frequently share in the cost of such general training.1 Becker argues that a firm which pays for the training of workers in skills of potential use to other firms will lose these workers: since other firms bear none of the costs of general training, they can attract a worker with such training by outbidding the firm which trained him. Recognising this absence of property rights over an investment in general training, firms will refuse to provide it. Hence, if general training is to take place, the trainee will have to pay for it. If potential trainees are unwilling or unable to pay, general training will not take place. A shortage in general training is likely to emerge; this may be especially pronounced in developing countries.2 In contrast, the outlook for

New trends in photobiology bactericidal effects of photoactivated porphyrins — An alternative approach to antimicrobial drugs

Abstract: Photoactivated porphyrins display a potent cytotoxic activity towards a variety of Gram positive bacteria, mycoplasma and yeasts, but not Gram negative cells. The prerequisite for photosensitization of a microbial cell is the binding of porphyrin to the cytoplasmic membrane in a pH-dependent manner. On illumination, the membrane bound, and possibly, cytoplasmic porphyrin molecules generate singlet oxygen and radicals which sensitize biomolecules and lead to cell death. The immediate inhibition of cell growth on photodynamic treatment is accompanied by alterations in cell wall and membrane synthesis, leading to the formation of large mesosomes adjacent to the unaccomplished septa. Hemin bound to microbial cells exerts cytotoxic activity by peroxidative and oxidative reactions independent of light. Future research in the field may enhance the possibility of using porphyrin photosensitization for treatment of microbial infections. Such clinical use will be unrelated to the antibiotic resistance of the pathogen. Resistance of Gram negative bacteria to porphyrin photosensitization is the main impediment to its use as a broad spectrum antibacterial method.

Looking through walls and around corners

Abstract: It is shown theoretically that under appropriate conditions a visually opaque, multiply scattering optical barrier can be made to serve as a thin lens which produces a near perfect, real, paraxial image of objects lying behind the barrier. Preliminary experimental results are described which verify the validity of the underlying assumptions. The barrier can also be made to serve as various other types of optical instruments, such as mirrors, polarizers, optical Fourier analyzers, theodolites, etc. Thus it is now clear that multiply scattering media should no longer be considered barriers to optical propagation, but are more properly to be regarded as potential high-precision optical instruments.

Rent-seeking for pure public goods*

Abstract: In this paper we present a formal analysis of rent-seeking for public goods by two or more groups with different numbers of individuals. We begin by considering equally wealthy groups under risk neutrality, a case which constitutes our basic model. Several surprising and interesting results emerge from the analysis of this basic case. The problem is then extended to deal with (a) groups with different wealth levels, and (b) risk aversion. This last extension brings about a further crop of interesting and useful results.

Interrelationships among anxiety, aggression, impulsivity, and mood: a serotonergically linked cluster?

Abstract: Serotonin abnormalities appear to be related to a variety of psychopathological dimensions such as anxiety, depressed mood, impulsivity, and aggression dysregulation. We hypothesized that the psychopathological dimensions related to serotonin would be significantly intercorrelated since they seem to have a common biological basis. Sixty psychiatric inpatients were examined on a series of psychometric tests measuring suicidality, violence potential, impulsivity, depressive mood, and anxiety. The scores on all of these measures tended to be significantly correlated with one another. These findings support the additional hypothesis that biological markers may be more closely related to basic psychological dimensions than to nosological categories.

The Effect of External Nutrient Resources on the Optical Properties and Photosynthetic Efficiency of Stylophora pistillata

Abstract: Enrichment of the hermatypic Red Sea coral Stylophora pistillata with dissolved inorganic nitrogen, inorganic nitrogen+phosphorus, and feeding on Artemia, all led to increases in areal pigmentation in comparison with control colonies. These increases, unlike photoadaptive ones, resulted from growth in cell numbers ranging from $\times $ 2.75 in the Artemia-fed to $\times $ 4.85 in the N+P-enriched corals. The treated corals absorbed 51-85% of incident light, whereas the controls absorbed only 33%. Areal photosynthesis increased with treatment, although to a lesser degree than absorptivity. This difference resulted in reduced photosynthetic efficiencies in the treated colonies. Photosynthetic rates, calculated on a percell basis, were inversely correlated with algal densities, indicating possible competition among the algae for CO$_{2}$.

Quality of Work Life and its Relation to Quality of Life

Abstract: Cette etude s'est donne pour objectifs de parvenir a une definition d'ensemble du concept “Qualite de la vie au travail” (QVT) et d‘eprouver empiriquement sa structure. On propose une definition multiple de la QVT et de ses relations avec la qualite de la vie en general basee sur la theorie systemique de l'action, ce qui fournit des criteres pour la selection des items et la formulation des hypotheses sur la structure des interrelations entre les dimensions de la QVT. Utilisant des donnees recuellies sur des echantillons de travailleurs hongrois, les hypotheses ont eteeprouvees au moyen de l'analyse du plus petit espace de Guttman. Les resultats confirment les hypotheses. On a obtenu un systeme conceptuel empirique doublement ordonne, une structure “radex” qui exprime les deux aspects de la definition de la QVT: mode de fonctionnement (expressif, integrateur, adaptateur, conservateur) et domaine de fonctionnement (psychologique, physique, social, culturel). La structure du monde de la QVT et de la qualite de la vie est comme prevu conique: la qualite de la vie occupe la base du cone et la QVT le sommet. La satisfaction procedant de la vie et du travail est situee entre les deux. The major objective of the present study was to suggest a comprehensive definitional framework for the quality of work life (QWL) concept and to test its structure empirically. A facet definition of QWL and its relation to quality of life (QOL) in general based on action systemic concepts is proposed, which provides guidelines for the selection of items and the formulation of hypotheses about the structure of interrelationships among components of QWL. Based on data collected from samples of Hungarian workers, the hypotheses were tested by means of Guttman's Smallest Space Analysis. The results support the hypotheses. An empirical doubly ordered conceptual system, a radex structure, was obtained that reflects the two facets of the definition of QWL: mode of functioning—expressive, integrative, adaptive and conservative; and field of functioning—psychological, physical, social and cultural. The structure of the total universe of QWL and QOL is a conical structure as hypothesised. Quality of life occupies the base of the cone and QWL the top. Satisfaction with life and work were found to be located between the two.

Process for the production of gelatin from fish skins

Abstract: A process for the production of gelatin from fish skins comprises the steps of: (a) cleaning the skins in order to remove therefrom substantially all superfluous material; (b) treating with dilute aqueous alkali; (c) washing with water until the washing water is substantially neutral; (d) treating with dilute aqueous mineral acid; (e) washing with water until the washing water is substantially neutral; (f) treating with dilute aqueous citric acid and/or another suitable organic acid; (g) washing with water until the washing water is substantially neutral; and (h) extracting with water at elevated temperatures not above about 55° c., the washed citric acid-treated skins. In practice, the present process employs much lower temperatures than known heretofore for the treatment steps, which results in a high quality product (e.g. absence of a fishy smell), compared with the prior art.

Psychological aspects of male infertility

Abstract: The aim of this research was to study the effect of suspected infertility on psychological functioning, comparing men who suspect that they are infertile (N = 107) with men who have no such suspicion (N = 30). Infertile men had lower self-esteem, higher anxiety and showed more somatic symptoms than fertile men. The effects of moderating variables on the psychological functioning of the subfertile men were analysed. The findings were that causality of infertility, feelings of hopelessness and global attribution were related to sexual inadequacy. Depression was uniquely related to stress of infertility and global attribution. Global attribution, though predictive of psychological consequences, was not affected by the objective variables of infertility.

Predicting Worker Turnover: An Assessment of Intent on Actual Separations

Abstract: The predictive ability of most turnover models emanates from a key construct measuring a worker's intention to withdraw from a work organization. Empirical evidence to collaborate this cardinal assumption has, however, only moderate support. To test the predictive value of intention to leave, a logistic regression model of combined cross-sectional and longitudinal survey data on workers'potential and actual turnover was initiated. The results demonstrate that actual turnover and intent are influenced by a separate set of factors with intent a poor predictor of turnover behavior. Age, tenure, wage level, and perceived chances for improvement at the job were found to have a significant impact on actual separation, but not on the intent to leave. Work repetitiveness, importance of improvement, and perception of co-workers' intent influence the intent to move, but not turnover. Perception of co-workers' intentions to leave and importance of improvement played a dual role for both intent and turnover, but much...

Styles of problem solving in suicidal individuals

Abstract: This study compared qualitative aspects of problem solving among suicide attempters, suicide ideators, and nonsuicidal patients. The subjects completed a suicidal intent scale and a problem-solving task involving three dilemmas. Problem solving was analyzed along eight qualitative categories: versatility of the various solutions, reliance on self versus others, activity versus passivity, confrontation versus avoidance, relevance of the solution to the problem, positive versus negative affect, reference to the future, and extremity of the solution. The statistical analysis yielded differences among the three groups. In general, the solutions of suicidal patients showed less versatility, more avoidance, less relevance, more negative affect, and less reference to the future than the solutions of the nonsuicidal patients. The suicide attempters and nonsuicidal patients offered more active solutions than did the suicide ideators. Our findings emphasize the importance of general coping styles, as well as energetic/motivational aspects and affective aspects of the problem-solving process. Some applications to therapy are discussed.

Second Order Properties of Error Surfaces: Learning Time and Generalization

Abstract: The learning time of a simple neural network model is obtained through an analytic computation of the eigenvalue spectrum for the Hessian matrix, which describes the second order properties of the cost function in the space of coupling coefficients. The form of the eigenvalue distribution suggests new techniques for accelerating the learning process, and provides a theoretical justification for the choice of centered versus biased state variables.

A murine fer testis-specific transcript (ferT) encodes a truncated Fer protein.

Abstract: A cDNA for a potential tyrosine kinase-encoding mRNA was isolated from a mouse testis cDNA library. In a survey of eight mouse tissues, a transcript of 2.4 kilobases restricted to testis tissue was found. The mRNA encodes a 453-amino-acid protein of 51,383 daltons, the smallest tyrosine kinase protein ever described. RNA synthesized from the cDNA template directs the synthesis of a 51,000-Mr protein in a cell-free translation system. The carboxy-terminal 409 amino acids are 98 and 90% identical to the carboxy halves of the rat and human Fer proteins, respectively. This suggests that the cDNA represents an alternatively spliced testis-specific fer mRNA and is therefore termed by us ferT. On the basis of the appearance time of the fer mRNA in the testis of maturing neonatal mice, we speculate on the role played by this protein in the development of this organ.

Sleep of chronic post‐traumatic patients

Abstract: The purpose of the present study was to investigate the sleep of people diagnosed as suffering from chronic Post-Traumatic Stress Disorder (PTSD). The sleep of seven chronic post-traumatic patients with no known physical injuries was compared with that of seven matched control subjects. The post-traumatic patients had poorer sleep: decreased sleep efficiency, increase in number of awakenings, and decreased SWS, as well as longer REM latency. It was also found that their complaints correlated with relevant sleep-monitored measures. The findings add further support for the inclusion of sleep difficulties in the definition of the Post-Traumatic Stress Disorder.

Identifying Attention Deficit Hyperactive Disorder with the WISC—R and the Stroop Color and Word Test.

Abstract: Twenty-nine children with a diagnosis of Attention Deficit Hyperactive Disorder (ADHD) were compared to a group of 21 emotionally disturbed (ED) children and a control group (CO) of 20 nonproblem children. The meaures used in the comparison were the 12 subtests of the Wechsler Intelligence Scale for Children-Revised (WISC-R) and the Stroop Color and Word Test (SCWT). The results showed that the CO group was superior to the ADHD and ED groups and that the ED group performed better than the ADHD group on most of the variables. A stepwise discriminant function analysis showed that similar WISC-R subtests differentiated between the ADHD group and the ED and CO groups. Two measures of the SCWT helped in discriminating between the ADHD and ED groups, but not between the ADHD and CO groups. The authors discuss the meaning of these findings and their contribution to better understanding of the ADHD group, its specific cognitive processing, and its problems.

Psychological adjustment of adoptive parents-to-be

Abstract: Adjustment and functioning of adoptive parents-to-be were examined during the last stage of expectancy, focusing on possible antecedents or determinants of successful parenting. Results failed to support expectations of short-term adverse effects from transitional stresses, and suggested that the expectancy period may not be equivalent for adoptive and biological parents, especially for mothers. Programmatic implications are discussed.

Fathers' Hospital Visits to Their Preterm Infants as a Predictor of Father-Infant Relationship and Infant Development

Abstract: This short-term longitudinal study assessed the degree to which the frequency of fathers' visits with their preterm infants in the hospital was associated with the quality of ongoing and long-term fathering and infant development. Data on fathering and infant development were collected during the hospital stay, at discharge, at 8 months of age, and at 18 months of age, using both questionnaires and observational schedules. The frequency of visits was significantly correlated with more extensive and positive patterns of fathering at discharge and later periods. It was also associated with more positive perceptions of the infant, as well as with weight gain during hospitalization and psychosocial aspects of later infant development during the first 18 months. The discussion emphasized possible ways in which early paternal contact in the hospital might influence fathers, mothers, and infants. The frequency of paternal visits was high-lighted as a variable useful in predicting high-risk parenting.

Universal polarization correlations and microstatistics of optical waves in random media

Abstract: Universal polarization correlation functions are derived for multiply scattered optical waves and found to be in excellent agreement with experiment for a wide variety of samples. New statistics, termed microstatistics, are found for the polarization-dependent fluctuations of intensity within a single coherence area of the scattered field. Theoretical and experimental results on the unique distribution functions describing these microstatistics are presented.

Statistical mechanics of a multilayered neural network

Abstract: Statistical mechanics is applied to estimate the maximal information capacity per synapse (${\mathrm{\ensuremath{\alpha}}}_{\mathit{c}}$) of a multilayered feedforward neural network, functioning as a parity machine. For a large number of hidden units, K, the replica-symmetric solution overestimates dramatically the capacity, ${\mathrm{\ensuremath{\alpha}}}_{\mathit{c}}$\ensuremath{\propto}${\mathit{K}}^{2}$. However, a one-step replica-symmetry breaking gives ${\mathrm{\ensuremath{\alpha}}}_{\mathit{c}}$\ensuremath{\sim}lnK/ln2, which coincides with a theoretical upper bound. It is suggested that this asymptotic behavior is exact. Results for finite K are also discussed.

The effect of a single whole-blood transfusion on cytokine secretion.

Abstract: The effect of a single whole-blood transfusion on the cascade of cytokine secretion was studied in patients with chronic renal failure. The results indicate that 1 week after blood transfusion, no significant changes were observed in the secretion of interleukin-2, colony-stimulating factor, tumor necrosis factor, and gamma-interferon. However, 2 weeks after blood transfusion, a sharp decrease was observed in the generation of these cytokines. A decrease of about 70% was observed in interleukin-2, tumor necrosis factor, and gamma-interferon secretion. The production of colony-stimulating factor 2 weeks after blood transfusion amounted to about 30% less than baseline levels. No statistical differences in interleukin-1 production were observed throughout the study. In addition, we found that the decrease in cytokine secretion was paralleled by a sharp increase in the in vitro secretion of prostaglandin E2. Thus the beneficial effect of blood transfusion on graft survival might be due in part to an immunosuppressive effect brought about by immunoregulatory changes via the cascade of cytokine secretion.