Showing papers by "Bar-Ilan University published in 1998"

Hepatitis C Viral Dynamics in Vivo and the Antiviral Efficacy of Interferon-α Therapy

Abstract: To better understand the dynamics of hepatitis C virus and the antiviral effect of interferon-alpha-2b (IFN), viral decline in 23 patients during therapy was analyzed with a mathematical model. The analysis indicates that the major initial effect of IFN is to block virion production or release, with blocking efficacies of 81, 95, and 96% for daily doses of 5, 10, and 15 million international units, respectively. The estimated virion half-life (t1/2) was, on average, 2.7 hours, with pretreatment production and clearance of 10(12) virions per day. The estimated infected cell death rate exhibited large interpatient variation (corresponding t1/2 = 1.7 to 70 days), was inversely correlated with baseline viral load, and was positively correlated with alanine aminotransferase levels. Fast death rates were predictive of virus being undetectable by polymerase chain reaction at 3 months. These findings show that infection with hepatitis C virus is highly dynamic and that early monitoring of viral load can help guide therapy.

Indication of a Universal Persistence Law Governing Atmospheric Variability

Abstract: We study the temporal correlations in the atmospheric variability by 14 meteorological stations around the globe, the variations of the daily maximum temperatures from their average values. We apply several methods that can systematically overcome possible nonstationarities in the data. We find that the persistence, characterized by the correlation C(s) of temperature variations separated by s days, approximately decays $C(s)\ensuremath{\sim}{s}^{\ensuremath{-}\ensuremath{\gamma}}$, with roughly the same exponent $\ensuremath{\gamma}\ensuremath{\cong}0.7$ for all stations considered. The range of this universal persistence law seems to exceed one decade, and is possibly even larger than the range of the temperature series considered.

Synthesis, Characterization, and Properties of Metallic Copper Nanoparticles

Abstract: Nanoscale particles of metallic copper clusters have been prepared by two methods, namely the thermal reduction and sonochemical reduction of copper(II) hydrazine carboxylate Cu(N2H3COO)2·2H2O complex in an aqueous medium. Both reduction processes take place under an argon atmosphere over a period of 2−3 h. The FT-IR, powder X-ray diffraction, and UV−visible studies support the reduction products of Cu2+ ions as metallic copper nanocrystallites. The powder X-ray analysis of the thermally derived products show the formation of pure metallic copper, while the sonochemical method yields a mixture of metallic copper and copper oxide (Cu2O). The formation of Cu2O along with the copper nanoparticles in the sonochemical process can be attributed to the partial oxidation of copper by in situ generated H2O2 under the sonochemical conditions. However, the presence of a mixture of an argon/hydrogen (95:5) atmosphere yields pure copper metallic nanoparticles, which could be due to the scavenging action of the hydroge...

Attachment working models and the sense of trust : An exploration of interaction goals and affect regulation

Abstract: Five studies examined the association between adult attachment style and the sense of trust in close relationships. Study 1 focused on the accessibility of trust-related memories. Studies 2-5 focused on trust-related goals and coping strategies, while using different data collection techniques (openended probes, diary methodology, lexical decision task). Findings showed that secure persons felt more trust toward partners, showed higher accessibility of positive trust-related memories, reported more positive trust episodes over a 3-week period, and adopted more constructive strategies in coping with the violation of trust than insecure persons. In addition, whereas intimacy attainment was the main trust-related goal for all the attachment groups, security attainment was an additional goal of anxious-ambivalent persons, and control attainment was an additional goal of avoidant persons. Findings are discussed in terms of attachment working models.

Prejudice toward Immigrants to Spain and Israel: An Integrated Threat Theory Analysis

Abstract: An integrated threat theory composed of four variables was used to predict attitudes toward immigrant groups in Spain and Israel. The four threats are symbolic threats based on value differences between groups; realistic threats to the power, resources, and well-being of the in-group; anxiety concerning social interaction with out-group members; and feelings of threat arising from negative stereotypes of the out-group. All four threats were significant predictors of attitudes toward one or more of the immigrant groups. It was predicted, and found, that intergroup anxiety and negative stereotypes were more powerful and consistent predictors of prejudicial attitudes toward immigrants than were realistic threats or symbolic threats. The implications of the theory for the causes and reduction of prejudice were discussed.

Perturbation of CD4 + and CD8 + T-cell repertoires during progression to AIDS and regulation of the CD4 + repertoire during antiviral therapy

Abstract: The T-cell antigen receptor (TCR) repertoire was studied longitudinally by analyzing the varying lengths of the beta chain CDR3 hypervariable region during the course of HIV-1 infection and following combination antiretroviral therapy. Drastic restrictions in CD8+ T-cell repertoire usage were found at all stages of natural progression and persisted during the first six months of treatment. In contrast, significant CD4+ T-cell repertoire perturbations were not found in early stages of infection but correlated with progression to AIDS. Out of ten patients presenting with pretreatment perturbations, normalization of the CD4+ repertoire was observed in eight good responders, but not in two cases of unsuccessful therapy. These results indicate that, besides CD4+ cell count rise, an efficient control of HIV replication may allow qualitative modifications of the CD4+ repertoire balance.

A chemokine receptor CCR2 allele delays HIV-1 disease progression and is associated with a CCR5 promoter mutation.

Abstract: Viral and host factors influence the rate of HIV-1 disease progression. For HIV-1 to fuse, a CD4+ cell must express a co-receptor that the virus can use. The chemokine receptors CCR5 and CXCR4 are used by R5 and X4 viruses, respectively. Most new infections involve transmission of R5 viruses, but variants can arise later that also use CXCR4 (R5-X4 or X4 viruses). This is associated with an increased rate of CD4+ T-cell loss and poor prognosis. The ability of host cells to support HIV-1 entry also influences progression. The absence of CCR5 in approximately 1% of the Caucasian population, due to homozygosity for a 32-nucleotide deletion in the coding region (delta32-CCR5 allele), very strongly protects against HIV-1 transmission. Heterozygosity for the delta32-CCR5 allele delays progression typically by 2 years. A recent study showed that a conservative substitution (V64I) in the coding region of CCR2 also has a significant impact on disease progression, but not on HIV-1 transmission. This was unexpected, since CCR2 is rarely used as a co-receptor in vitro and the V64I change is in a transmembrane region. Because a subsequent study did not confirm this effect on progression to disease, we analyzed CCR2-V64I using subjects in the Chicago MACS. We show that CCR2-V64I is indeed protective against disease progression and go on to show that the CCR2-V64I allele is in complete linkage disequilibrium with a point mutation in the CCR5 regulatory region.

Normal families: New perspectives

Abstract: This paper surveys some surprising applications of a lemma characterizing normal families of meromorphic functions on plane domains. These include short and efficient proofs of generalizations of (i) the Picard Theorems, (ii) Gol’dberg’s Theorem (a meromorphic function on C which is the solution of a first-order algebraic differential equation has finite order), and (iii) the Fatou-Julia Theorem (the Julia set of a rational function of degree d ≥ 2 is the closure of the repelling periodic points). We also discuss Bloch’s Principle and provide simple solutions to some problems of Hayman connected with this principle. Over twenty years ago, on the way to a partial explication of the phenomenon known as Bloch’s Principle, I proved a little lemma characterizing normal families of holomorphic and meromorphic functions on plane domains [68]. Over the years, the lemma has grown and, in dextrous hands, proved amazingly versatile, with applications to a wide variety of topics in function theory and related areas. With the renewed interest in normal families (arising largely from the important role they play in complex dynamics), it seems sensible to survey some of the most striking of these applications to the one-variable theory, with the aim of making this technique available to as broad an audience as possible. That is the purpose of this report. One pleasant aspect of the theory is that judicious application of the lemma often leads to proofs which seem almost magical in their brevity. In such cases, we have made no effort to resist the temptation to write out complete proofs. Hardly anything beyond a basic knowledge of function theory is required to understand what follows, so the reader is urged to take courage and plough on through. And now we turn to our tale. 1. Let D be a domain in the complex plane C. We shall be concerned with analytic maps (i.e., meromorphic functions) f : (D, | |R2) → (Ĉ, χ) Received by the editors October 15, 1997, and, in revised form, May 26, 1998. 1991 Mathematics Subject Classification. Primary 30D45; Secondary 30D35, 34A20, 58F23.

Conceptualizing and Measuring a Power/Interaction Model of Interpersonal Influence1

Abstract: In response to new theoretical conceptualizations (Raven, 1992, 1993), an instrument was developed to measure 11 bases of power, the original 6 French and Raven (1959; Raven, 1965) bases of power, with 3 of these further differentiated: reward (personal, impersonal), coercion (personal. impersonal), legitimate (position, reciprocity, equity, dependence), expert, referent, and information. In Study 1, 317 American student respondents rated the likelihood that each of these power bases contributed to a supervisor successfully influencing a subordinate in a series of hypothetical situations. The internal consistency of the items which made up the 11 power bases proved adequate. Factor analysis found 7 factors and 2 categories of bases: harsh and soft. In Study 2, which used 101 Israeli health workers, the earlier findings were generally supported. In addition, job satisfaction was found to be positively related to the attribution of soft bases to the supervisor.

Sonochemical Preparation and Size-Dependent Properties of Nanostructured CoFe2O4 Particles

Abstract: Nanostructured CoFe2O4 particles were prepared by a sonochemical approach, first by preparation of the amorphous precursor powders, followed by heat treatment at relatively very low temperatures. The precursor was prepared by sonochemical decomposition of solutions of volatile organic precursors, Fe(CO)5 and Co(NO)(CO)3, in Decalin at 273 K, under an oxygen pressure of 100−150 kPa. The amorphous nature of these particles was confirmed by various techniques, such as scanning and transmission electron microscopy (SEM and TEM), electron microdiffraction, and X-ray diffractograms. Magnetic measurements, Mossbauer, and electron paramagnetic resonance (EPR) spectral studies indicated that the as-prepared amorphous particles were superparamagnetic. The Mossbauer parameters and the significantly low (45 emu/g) observed saturation of magnetization of the annealed sample, compared to that of the bulk sample (72 emu/g), reflected its nanocrystalline nature.

Adult attachment style and individual differences in functional versus dysfunctional experiences of anger

Abstract: Three studies examined the association between adult attachment and anger. Study 1 examined attachment-style differences in self-reports of anger-proneness, anger expression, anger goals, and responses to anger. Study 2 assessed attachment style, physiological signs of anger, and attribution of hostile intent. Study 3 used a lexical-decision task for studying attachment-style differences in expected anger outcome. Secure persons scored lower in anger-proneness, endorsed more constructive anger goals, reported more adaptive responses and more positive affect in anger episodes, attributed less hostile intent to others, and expected more positive outcomes than insecure persons. For ambivalent persons, the anger experience also included lack of anger control and anger-in. For avoidant persons, it included high hostility, escapist responses, and lack of awareness of physiological signs of anger. The underlying action of working models is emphasized in the discussion.

Adult attachment style and affect regulation: strategic variations in self-appraisals

Abstract: Four studies examined the link between adult attachment style and strategic variations in self-appraisals. Whereas secure persons held a stable positive self-view, Studies 1-2 showed that avoidant persons showed a positive self-view and anxious-ambivalent persons a negative self-view, which were strengthened by distress arousal and weakened by factors that inhibit the activation of regulatory mechanisms. Studies 3-4 indicated that insecure persons' self-views varied in accordance with specific attachment-related concerns and needs. Avoidant persons' positive self-view was related to their attempts to validate their sense of self-reliance, and anxious-ambivalent persons' negative self-view was related to their attempts to win others' compassion and affection. Results are discussed in terms of attachment-related strategies of affect regulation.

780 nm low power diode laser irradiation stimulates proliferation of keratinocyte cultures: Involvement of reactive oxygen species

Abstract: Background and Objective The purpose of this study was to determine irradiation parameters of a 780 nm low power CW diode laser (6.5 mW) leading to enhanced proliferation of cultured normal human keratinocytes (NHK). The possible role of reactive oxygen species (ROS) in this response was evaluated. Study Design/Materials and Methods: NHK were exposed to a single dose of 0 to 3.6 J/cm2 (0–180 sec) of irradiation. Proliferation parameters studied were: incorporation of 3H-thymidine during 6–24 hr following irradiation; percentage of dividing cells and number of cells, 24 hr and 48 hr following irradiation, respectively. Results Proliferation of NHK exposed to 0.45–0.95 J/cm2 was significantly enhanced by 1.3–1.9-folds relative to sham-irradiated controls, as inferred from parameters studied. Exposure to other energy densities was considerably less affective in enhancing proliferation parameters. Added enzymatic antioxidants, superoxide dismutase or catalase, scavenging superoxide anions and H2O2, suppressed this enhanced proliferation. Added scavengers (α-tocopherol acetate, scavenging lipid peroxidation, or sodium azide, histidine, mannitol, scavenging singlet oxygen, superoxide anions, and hydroxyl radicals, respectively), or N-acetyl cysteine, the thiol-reducing agent, suppressed the response, but to different extents. Conclusions The results indicate that 780 nm low power diode laser irradiation enhanced keratinocytes proliferation in vitro, with an apparent involvement of ROS in this response, and comparably, might be used to promote their proliferation in vivo to enhance wound healing. Lasers Surg. Med. 22:212–218, 1998. © 1998 Wiley-Liss, Inc.

The impact of climate change on geomorphology and desertification along a mediterranean- arid transect

Abstract: From the perspective of geomorphology, three important aspects of climate should be considered if conditions become more arid: (a) any decrease that might occur in the annual rainfall amount; (b) the duration of rainfall events; and (c) any increase in the intervals between rainfall events. These, together with increasing temperature, lead to less available water, less biomass and soil organic matter content and hence to a decrease in aggregate size and stability. As a consequence, the soil permeability decreases, soils develop surface crusts and infiltration rates decrease dramatically. Such changes in vegetation cover and soil structure lead to an increase in overland flow and in the erosion of the fertile topsoil layer. Positive feedback mechanisms may reinforce these eAects and lead to desertification. This paper considers the results of field investigations into the spatial variability of a number of ‘quick response’ variables at two scales: the regional and the plot scales. Concerning the regional scale spatial variability, results of experimental field work conducted along a climatic transect, from the Mediterranean climate to the arid zone in Israel, show that: (1) organic matter content, and aggregate size and stability decrease with aridity, while the sodium adsorption ratio and the runoA coeAcient increase; and (2) the rate of change of these variables along the climatic transect is non-linear. A steplike threshold exists at the semiarid area, which sharply separates the Mediterranean climate and arid ecogeomorphic systems. This means that only a relatively small climatic change would be needed to shift the borders between these two systems. As many regions of Mediterranean climate lie adjacent to semiarid areas, they are threatened by desertification in the event of climate change. Concerning spatial variability at the plot scale, diAerent patterns of overland flow generation and continuity characterize hillslopes under diAerent climatic conditions. While in the Mediterranean climate area infiltration is the dominant process all over the hillslope, in the arid area overland flow predominates. In contrast to the uniform distribution of processes in these two zones, a mosaic-like pattern, consisting of locally ‘arid’ water contributing and ‘moist’ water accepting patches is typical of the transitional semiarid area. Such pattern is strengthened by fires or grazing which are characteristic of this area. The development of such mosaic pattern enables most rainfall to be retained on hillslopes. Changes in the spatial pattern of contributing versus accepting waterareas can be used as an indicatorof desertification and applied to developing rehabilitation strategies. #1998 John Wiley & Sons, Ltd.

Role of nerve growth factor in a mouse model of allergic airway inflammation and asthma.

Abstract: The role of nerve growth factor (NGF), a potent mediator acting in the development and differentiation of both neuronal and immune cells, was examined in a mouse model of allergic asthma. NGF-positive cells were detected in the inflammatory infiltrate of the lung and enhanced levels of NGF were detected in serum and broncho-alveolar lavage fluids. Mononuclear cells in inflamed airway mucosa as well as broncho-alveolar macrophages were identified as one source of NGF production. Splenic mononuclear cells from allergen-sensitized mice produced NGF in response to allergen. They responded to exogenously added NGF with a dose-dependent increase in IL-4 and IL-5 production and augmented IgE and IgG1 synthesis. In contrast, IFN-gamma and IgG2alpha levels remained unaffected. The effects were NGF specific, since they could be blocked by an anti-NGF-antibody. Nasal application of anti-NGF to allergen-sensitized mice significantly reduced IL-4 and prevented development of airway hyperreactivity. These results show that allergic airway inflammation is accompanied by enhanced local NGF production that acts as an amplifier for Th2 effector functions and plays an important role in the development of airway hyperreactivity. Therefore it is suggested that NGF may serve as a link between the immune and nerve system.

Influence of delayed viral production on viral dynamics in HIV-1 infected patients.

Abstract: We present and analyze a model for the interaction of human immunodeficiency virus type 1 (HIV-1) with target cells that includes a time delay between initial infection and the formation of productively infected cells. Assuming that the variation among cells with respect to this 'intracellular' delay can be approximated by a gamma distribution, a high flexible distribution that can mimic a variety of biologically plausible delays, we provide analytical solutions for the expected decline in plasma virus concentration after the initiation of antiretroviral therapy with one or more protease inhibitors. We then use the model to investigate whether the parameters that characterize viral dynamics can be identified from biological data. Using non-linear least-squares regression to fit the model to simulated data in which the delays conform to a gamma distribution, we show that good estimates for free viral clearance rates, infected cell death rates, and parameters characterizing the gamma distribution can be obtained. For simulated data sets in which the delays were generated using other biologically plausible distributions, reasonably good estimates for viral clearance rates, infected cell death rates, and mean delay times can be obtained using the gamma-delay model. For simulated data sets that include added simulated noise, viral clearance rate estimates are not as reliable. If the mean intracellular delay is known, however, we show that reasonable estimates for the viral clearance rate can be obtained by taking the harmonic mean of viral clearance rate estimates from a group of patients. These results demonstrate that it is possible to incorporate distributed intracellular delays into existing models for HIV dynamics and to use these refined models to estimate the half-life of free virus from data on the decline in HIV-1 RNA following treatment.

Heterogeneous neurochemical responses to different stressors: a test of Selye’s doctrine of nonspecificity

Abstract: Selye defined stress as the nonspecific response of the body to any demand. Stressors elicit both pituitary-adrenocortical and sympathoadrenomedullary responses. One can test Selye’s concept by com...

Power law scaling for a system of interacting units with complex internal structure

Abstract: We study the dynamics of a system composed of interacting units each with a complex internal structure comprising many subunits and treat the case in which each subunit grows in a multiplicative manner. We propose a model for such systems in which the interaction among the units is treated in a mean field approximation and the interaction among subunits is nonlinear. We test the model and find agreement between our predictions and empirical results based on a large economics database spanning 20 years. [S0031-9007(98)05355-1]

Spontaneous Stratification in Granular Mixtures

Abstract: Granular materials size segregate when exposed to external periodic perturbations such as vibrations. Moreover, mixtures of grains of different sizes spontaneously segregate in the absence of external perturbations: when a mixture is simply poured onto a pile, the large grains are more likely to be found near the base, while the small grains are more likely to be near the top. Here, we report a spontaneous phenomenon arising when we pour a mixture between two vertical plates: the mixture spontaneously stratifies into alternating layers of small and large grains whenever the large grains are rougher than the small grains. In contrast, we find only spontaneous segregation when the large grains are more rounded than the small grains. The stratification is related to the occurrence of avalanches; during each avalanche the grains comprising the avalanche spontaneously stratify into a pair of layers through a "kink" mechanism, with the small grains forming a sublayer underneath the layer of large grains.

Modeling urban growth patterns with correlated percolation

Abstract: We propose and test a model that describes the morphology of cities, the scaling of the urban perimeter of individual cities, and the area distribution of systems of cities. The model is also consistent with observable urban growth dynamics, our results agreeing both qualitatively and quantitatively with urban data. The resulting growth morphology can be understood from interactions among the constituent units forming an urban region, and can be modeled using a correlated percolation model in the presence of a gradient. @S1063-651X~98!04012-4#

Text Mining at the Term Level

Abstract: Knowledge Discovery in Databases (KDD) focuses on the computerized exploration of large amounts of data and on the discovery of interesting patterns within them. While most work on KDD has been concerned with structured databases, there has been little work on handling the huge amount of information that is available only in unstructured textual form. Previous work in text mining focused at the word or the tag level. This paper presents an approach to performing text mining at the term level. The mining process starts by preprocessing the document collection and extracting terms from the documents. Each document is then represented by a set of terms and annotations characterizing the document. Terms and additional higher-level entities are then organized in a hierarchical taxonomy. In this paper we will describe the Term Extraction module of the Document Explorer system, and provide experimental evaluation performed on a set of 52,000 documents published by Reuters in the years 1995–1996.

Interferon Resistance of Hepatitis C Virus Genotype 1b: Relationship to Nonstructural 5A Gene Quasispecies Mutations

Abstract: A 40-amino-acid sequence located in the nonstructural 5A (NS5A) protein of hepatitis C virus genotype 1b (HCV-1b) was recently suggested to be the interferon sensitivity-determining region (ISDR), because HCV-1b strains with an ISDR amino acid sequence identical to that of the prototype strain HCV-J were found to be resistant to alpha interferon (IFN-α) whereas strains with amino acid substitutions were found to be sensitive (N. Enomoto, I. Sakuma, Y. Asahina, M. Kurosaki, T. Murakami, C. Yamamoto, N. Izumi, F. Marumo, and C. Sato, J. Clin. Invest. 96:224–230, 1995; N. Enomoto, I. Sakuma, Y. Asahina, M. Kurosaki, T. Murakami, C. Yamamoto, Y. Ogura, N. Izumi, F. Marumo, and C. Sato, N. Engl. J. Med. 334:77–81, 1996). We used single-strand conformation polymorphism (SSCP) analysis, combined with cloning and sequencing strategies, to characterize NS5A quasispecies in HCV-1b-infected patients and determine the relationships between pre- and posttreatment NS5A quasispecies mutations and the IFN-α sensitivity of HCV-1b. The serine residues involved in phosphorylation of NS5A protein were highly conserved both in the various patients and in quasispecies in a given patient, suggesting that phosphorylation is important in NS5A protein function. A hot spot for amino acid substitutions was found at positions 2217 to 2218; it could be the result of either strong selection pressure or tolerance to these amino acid replacements. The proportion of synonymous mutations was significantly higher than the proportion of nonsynonymous mutations, suggesting that genetic variability in the region studied was the result of high mutation rates and viral replication kinetics rather than of positive selection. Sustained HCV RNA clearance was associated with low viral load and low nucleotide sequence entropy, suggesting (i) that the replication kinetics when treatment is started plays a critical role in HCV-1b sensitivity to IFN-α and (ii) that HCV-1b resistance to IFN-α could be conferred by numerous and/or related mutations that could be patient specific and located at different positions throughout the viral genome and could allow escape variants to be selected by IFN-α-stimulated immune responses. No NS5A sequence appeared to be intrinsically resistant or sensitive to IFN-α, but the HCV-J sequence was significantly more frequent in nonresponder quasispecies than in sustained virological responder quasispecies, suggesting that the balance between NS5A quasispecies sequences in infected patients could have a subtle regulatory influence on HCV replication.

The influence of film-induced mood on pain perception.

Abstract: It has been shown that a person's mood can influence pain tolerance Films have been used as a means of inducing a desired mood The effect on pain perception of film type and film length to induce mood was investigated Previous research with brief humorous films had not indicated any unique advantage of humor over distraction approaches Other recent research had indicated that after exposure to film stimulation there is a need to wait approximately 40 min before physiological changes can be obtained Thus, the present study varied both film type and length and introduced a 30-min waiting period following the mood induction via film prior to exposure to cold-pressor pain Two hundred subjects in nine different groups participated in the study Three types of films were used: (1) humorous, (2) holocaust, (3) neutral Three lengths of each type were also used: 15 min, 30 min, and 45 min In addition, a tenth no-film group served as a control for the effects of a film Each subject was given a baseline trial of cold-pressor pain, a trial immediately following the film and a trial 30 min later Results indicated an advantage in increased pain tolerance for the humorous film and an increased pain tolerance for the longer film regardless of type only after the 30-min waiting period Results were discussed from a pain theoretical perspective with emphasis placed on returning to psychological manipulations of the sensory aspects of pain and not just the cognitive/emotional/motivational dimensions

Adult attachment style and affect regulation: Strategic variations in subjective self–other similarity.

Abstract: Six studies examined the link between adult attachment style and subjective self-other similarity. In Studies 1-3, data were collected on representations of self-other similarity in the realms of traits and opinions. Studies 4-5 examined the effects of affective inductions on the link between attachment and self-other similarity. Study 6 examined the cognitive maneuvers people differing in attachment style use for changing self-other similarity upon distress arousal. Whereas avoidant persons underestimated self-other similarity and anxious-ambivalent persons overestimated it, secure persons provided more accurate similarity scores. These differences were exacerbated by negative affect and mitigated by positive affect. Insecure persons' distortions resulted from transformations they made in representations of the self and others. Results are discussed in terms of attachment theory.

Mining Text Using Keyword Distributions

Abstract: Knowledge Discovery in Databases (KDD) focuses on the computerized exploration of large amounts of data and on the discovery of interesting patterns within them. While most work on KDD has been concerned with structured databases, there has been little work on handling the huge amount of information that is available only in unstructured textual form. This paper describes the KDT system for Knowledge Discovery in Text, in which documents are labeled by keywords, and knowledge discovery is performed by analyzing the co-occurrence frequencies of the various keywords labeling the documents. We show how this keyword-frequency approach supports a range of KDD operations, providing a suitable foundation for knowledge discovery and exploration for collections of unstructured text.

Developmental Schedule of the Postnatal Rat Testis Determined by Flow Cytometry

Abstract: Analysis of the biochemical events and the genes expressed at various postnatal developmental stages in the testis of mammals is of great importance for understanding spermatogenesis in general and meiosis in particular. A prerequisite for such an analysis is the characterization of a detailed developmental schedule of the postnatal testis. In this study we used four-parameter flow cytometry analysis to determine a detailed testicular developmental schedule in rats as compared to mice. A dot plot of forward-scatter/side-scatter of testicular cell suspensions from mature animals revealed 7 distinct subpopulations within the testis. These, when analyzed by fluorescence parameters, were divided into 4 levels of fluorescence: cells containing 4d DNA, 2d DNA, and 2 levels of haploid cells. Observing the acquisition pattern of these subpopulations during postnatal development, we were able to suggest the following developmental schedule for the rat. At postnatal Days 6-7, the testis contains somatic cells and spermatogonia cells only. By Days 13-14, leptotene spermatocytes appear; by Days 17-18, zygotene spermatocytes are present; by Days 19-20 and Days 22-23, early and late pachytene spermatocytes, respectively, are seen. Haploid round spermatids first appear at Days 24-25 and elongating spermatids by Days 30-31; by Day 36, elongated spermatozoa can be found.