Showing papers by "Bar-Ilan University published in 2003"

Attachment Theory and Affect Regulation: The Dynamics, Development, and Cognitive Consequences of Attachment-Related Strategies

Abstract: Attachment theory (J. Bowlby, 1982/1969, 1973) is one of the most useful and generative frameworks for understanding both normative and individual-differences aspects of the process of affect regulation. In this article we focus mainly on the different attachment-related strategies of affect regulation that result from different patterns of interactions with significant others. Specifically, we pursue 3 main goals: First, we elaborate the dynamics and functioning of these affect-regulation strategies using a recent integrative model of attachment-system activation and dynamics (P. R. Shaver & M. Mikulincer, 2002). Second, we review recent findings concerning the cognitive consequences of attachment-related strategies following the arousal of positive and negative affect. Third, we propose some integrative ideas concerning the formation and development of the different attachment-related strategies.

The two faces of transformational leadership: Empowerment and dependency.

Abstract: Followers' identification with the leader and the organizational unit, dependence on the leader, and empowerment by the leader are often attributed to transformational leadership in organizations. However, these hypothesized outcomes have received very little attention in empirical studies. Using a sample of 888 bank employees working under 76 branch manages, the authors tested the relationships between transformational leadership and these outcomes. They found that transformational leadership was positively related to both followers' dependence and their empowerment and that personal identification mediated the relationship between transformational leadership and followers' dependence on the leader, whereas social identification mediated the relationship between transformational leadership and followers' empowerment. The authors discuss the implications of these findings to both theory and practice.

Determination of the Electron Lifetime in Nanocrystalline Dye Solar Cells by Open‐Circuit Voltage Decay Measurements

Abstract: Recently, a new class of photoelectrochemical cells based on nanoscaled porous metal oxide semiconductors (dye-sensitized solar cell) has promoted intense research due to the prospects of cheap and efficient conversion of visible light into electricity and of new applications such as transparent solar cells. It is widely agreed that the electron-transfer kinetics play a major role in determining the energy conversion efficiency of dye-sensitized solar cells. 3] Herein, we develop a new powerful tool to study the electron lifetime in dye solar cells as a function of the photovoltage (Voc) ; the open-circuit voltage-decay (OCVD) technique. This technique has certain advantages over frequenIn summary, the temperature effect on the arrangement of stilbenoid dendrimers on HOPG is presented in this work. It is seen that SD12 molecules form well-ordered hexagonal nanostructures at 16 C. However, if the adlayer is annealed at 65 C, the adlayer structure is changed into a well-ordered parallelogram nanostructure in a close-packed arrangement with a higher surface coverage. The phenomenon described here supports the earlier reports on two liquid-crystalline phases for SD12. The results in this research are useful in understanding the phase transition of SD12 as well as metastable complex systems with temperature.

Efficient immunization strategies for computer networks and populations.

Abstract: We present an effective immunization strategy for computer networks and populations with broad and, in particular, scale-free degree distributions. The proposed strategy, acquaintance immunization, calls for the immunization of random acquaintances of random nodes (individuals). The strategy requires no knowledge of the node degrees or any other global knowledge, as do targeted immunization strategies. We study analytically the critical threshold for complete immunization. We also study the strategy with respect to the susceptible-infected-removed epidemiological model. We show that the immunization threshold is dramatically reduced with the suggested strategy, for all studied cases.

The relationship between emotional intelligence and work attitudes, behavior and outcomes: An examination among senior managers

Abstract: The literature suggests that managerial skills in general, and emotional intelligence in particular, play a significant role in the success of senior managers in the workplace. This argument, despite its popularity, remains elusive. This can be attributed to the fact that although a few studies have provided evidence to support this argument, it has not received an appropriate empirical investigation. This study attempts to narrow this gap by empirically examining the extent to which senior managers with a high emotional intelligence employed in public sector organizations develop positive work attitudes, behavior and outcomes. The results indicate that emotional intelligence augments positive work attitudes, altruistic behavior and work outcomes, and moderates the effect of work‐family conflict on career commitment but not the effect on job satisfaction.

Scale-free networks are ultrasmall.

Abstract: We study the diameter, or the mean distance between sites, in a scale-free network, having N sites and degree distribution p(k) proportional, variant k(-lambda), i.e., the probability of having k links outgoing from a site. In contrast to the diameter of regular random networks or small-world networks, which is known to be d approximately ln(N, we show, using analytical arguments, that scale-free networks with 2 3, d approximately ln(N. We also show that, for any lambda>2, one can construct a deterministic scale-free network with d approximately ln(ln(N, which is the lowest possible diameter.

Peer interaction and loneliness in high-functioning children with autism.

Abstract: Social interaction with peers and the understanding and feelings of loneliness were examined in 18 high-functioning children with autism and 17 typically developing children matched for IQ, chronological age, gender, and maternal education. Observations were conducted on children's spontaneous social initiations and responses to their peers in natural settings such as recess and snack time, and children reported on their understanding and feelings of loneliness and social interaction. Overall, children with autism revealed a good understanding of both social interaction and loneliness, and they demonstrated a high level of social initiation. However, they spent only half the time in social interactions with peers compared with their matched counterparts, and they interacted more often with a typically developing child than with another special education child. Despite the intergroup differences in frequency of interaction, a similar distribution of interactions emerged for both groups, who presented mostly positive social behaviors, fewer low-level behaviors, and very infrequent negative behaviors. Children with autism reported higher degrees of loneliness than their typical age-mates, as well as a lower association between social interaction and loneliness, suggesting their poorer understanding of the relations between loneliness and social interaction. Research and practice implications of these findings are discussed.

Infant-mother and infant-father synchrony: The coregulation of positive arousal.

Abstract: To examine the coregulation of positive affect during mother-infant and father-infant in- teractions, 100 couples and their first-born child were videotaped in face-to-face interactions. Parents' and infant's affective states were coded in one-second frames, and synchrony was measured with time- series analysis. The orientation, intensity, and temporal pattern of infant positive arousal were assessed. Synchrony between same-gender parent-infant dyads was more optimal in terms of stronger lagged associations between parent and infant affect, more frequent mutual synchrony, and shorter lags to re- sponsiveness. Infants' arousal duringmother-infant interaction cycled between medium and low levels, and high positive affect appeared gradually and was embedded within a social episode. During father- child play, positive arousal was high, sudden, and organized in multiple peaks that appeared more fre- quently as play progressed. Mother-infant synchrony was linked to the partners' social orientation and was inversely related to maternal depression and infant negative emotionality. Father-child synchrony was related to the intensity of positive arousal and to father attachment security. Results contribute to research on the regulation of positive emotions and describe the unique modes of affective sharing that infants coconstruct with mother and father. RESUMEN: Para examinar la co-regulacion del afecto positivo durante las interacciones entre la madre y su hijo y el padre y su hijo, cien parejas y sus hijos primerizos fueron grabadas en video en sesiones de interacciones cara a cara. Los estados afectivos de los padres y de los infantes fueron codificados en marcos de un segundo, y la sincronia se midiopor medio de un analisis de tiempo en serie. Se evaluaron la orientacion, la intensidad, y el patron temporal del despertar positivo del infante. La sincronia entre las diadas del mismo sexo (madre-hija o padre-hijo) fue mas optima en terminos de mas fuertes asocia- ciones espaciadas del afecto entre padre/madre e infante, la mas frecuente mutua sincronia, y mas cortos espacios de sensibilidad.. El despertar de los ninos durante la interaccion entre la madre y su infante osciloentre los niveles medio y bajo, y el afecto positivo alto apareciogradualmente y se encontraba metido dentro de una situacion social. Durante el juego entre el padre y su infante, el despertar positivo fue alto, rapido y organizado en multiples puntos maximos que aparecieron con mayor frecuencia a medida que el juego progresaba. La sincronia entre la madre y su infante fue asociada con la orientacion social de los participantes y fue inversamente relacionada con la depresion maternal y la negativa emo- cionalidad del infante. La sincronia entre el padre y su infante fue relacionada con la intensidad del despertar positivo y con la seguridad de la afectividad paterna. Los resultados contribuyen a la investi- gacion sobre la regulacion de las emociones positivas y describen los modelos unicos de la afectividad compartida que los infantes co-construyen con la madre y el padre.

Regulation of cell apoptosis by protein kinase c δ

Abstract: The isoforms of the PKC family are activated in response to mitogenic stimuli, to inflammatory stimuli, and to stress and play important roles in a variety of cellular functions including apoptosis. PKCδ a member of the novel PKC subfamily, is actively involved in cell apoptosis in a stimulus and tissue specific manner; it both regulates the expression and function of apoptotic related proteins and is itself a target for caspases. Activation of PKCδ by various apoptotic stimuli results in the translocation of PKCδ to distinct cellular compartments such as mitochondria, golgi and nucleus, and the differential translocation contributes to its different effects. In addition, phosphorylation of PKCδ on distinct tyrosine residues and its association with specific apoptotic related proteins such as c-Abl, DNA-PK, p73 and lamin B are pivotal to its function in cell apoptosis. Recent findings on these aspects of the PKCδ cascades are the major focus of this review.

The Existential Function of Close Relationships: Introducing Death Into the Science of Love

Abstract: Originally, terror management theory proposed two psychological mechanisms in dealing with the terror of death awareness-cultural worldview validation and self-esteem enhancement. In this article, we would like to promote the idea of close relationships as an additional death-anxiety buffering mechanism and review a growing body of empirical data that support this contention. Based on a comprehensive analysis of the sociocultural and personal functions of close relationships, we formulate two basic hypotheses that have received empirical support in a series of experimental studies. First, death reminders heighten the motivation to form and maintain close relationships. Second, the maintenance of close relationships provides a symbolic shield against the terror of death, whereas the breaking of close relationships results in an upsurge of death awareness. In addition, we present empirical evidence supporting the possibility that close relationships function as a related yet separate mechanism from the self-esteem and cultural worldview defenses.

Enhancing Mathematical Reasoning in the Classroom: The Effects of Cooperative Learning and Metacognitive Training

Abstract: The purpose of this study was to investigate the effects of four instructional methods on students’ mathematical reasoning and metacognitive knowledge. The participants were 384 eighth-grade students. The instructional methods were cooperative learning combined with metacognitive training (COOP+META), individualized learning combined with metacognitive training (IND+META), cooperative learning without metacognitive training (COOP), and individualized learning without metacognitive training (IND). Results showed that the COOP+META group significantly outperformed the IND +META group, which in turn significantly outperformed the COOP and IND groups on graph interpretation and various aspects of mathematical explanations. Furthermore, the metacognitive groups (COOP+META and IND +META) outperformed their counterparts (COOP and IND) on graph construction (transfer tasks) and metacognitive knowledge. This article presents theoretical and practical implications of the findings.

Eradication of Propionibacterium acnes by its endogenic porphyrins after illumination with high intensity blue light

Abstract: Propionibacterium acnes is a Gram-positive, microaerophilic bacterium that causes skin wounds. It is known to naturally produce high amounts of intracellular porphyrins. The results of the present study confirm that the investigated strain of P. acnes is capable of producing endogenic porphyrins with no need for any trigger molecules. Extracts from growing cultures have demonstrated emission peaks around 612 nm when excited at 405 nm, which are characteristic for porphyrins. Endogenic porphyrins were determined and quantified after their extraction from the bacterial cells by fluorescence intensity and by elution retention time on high-performance liquid chromatography (HPLC). The porphyrins produced by P. acnes are mostly coproporphyrin, as shown by the HPLC elution patterns. Addition of δ-aminolevulinic acid (ALA) enhanced intracellular porphyrin synthesis and higher amounts of coproporphyrin have been found. Eradication of P. acnes by its endogenic porphyrins was examined after illumination with intense blue light at 407–420 nm. The viability of 24 h cultures grown anaerobically in liquid medium was reduced by less than two orders of magnitude when illuminated once with a light dose of 75 J cm−2. Better photodynamic effects were obtained when cultures were illuminated twice or three times consecutively with a light dose of 75 J cm−2 and an interval of 24 h between illuminations. The viability of the culture under these conditions decreased by four orders of magnitude after two illuminations and by five orders of magnitude after three illuminations. When ALA-triggered cultures were illuminated with intense blue light at a light dose of 75 J cm−2 the viability of the treated cultures decreased by seven orders of magnitude. This decrease in viability can occur even after a single exposure of illumination for the indicated light intensity. X-ray microanalysis and transmission electron microscopy revealed structural damages to membranes in the illuminated P. acnes. Illumination of the endogenous coproporphyrin with blue light (407–420 nm) apparently plays a major role in P. acnes photoinactivation. A treatment protocol with a series of several illuminations or illumination after application of ALA may be suitable for curing acne. Treatment by both pathways may overcome the resistance of P. acnes to antibiotic treatment.

Payments and banking with mobile personal devices

Abstract: Mobile devices enable secure, convenient authorization of e-banking, retail payment, brokerage, and other types of transactions.

Skin-to-skin contact (Kangaroo Care) accelerates autonomic and neurobehavioural maturation in preterm infants.

Abstract: The effects of mother–infant skin-to-skin contact (Kangaroo Care; KC) on autonomic functioning, state regulation, and neurobehavioural status was examined in 70 preterm infants, half of whom received KC over 24.31 days (SD 7.24) for a total of 29.76 hours (SD 12.86). Infants were matched for sex (19 males and 16 females in each group); birthweight (KC, 1229.95g [SD 320.21]; controls, 1232.17g [SD 322.15]); gestational age (GA) (KC, 30.28 weeks [SD 2.54]; controls, 30.19 weeks [SD 2.65]); medical risk; and family demographics. Vagal tone was calculated from 10 minutes of heart rate before KC and again at 37 weeks' GA. Infant state was observed in 10-second epochs during four consecutive hours before KC and again at 37 weeks' GA. Neurobehavioural status was assessed at 37 weeks' GA with the Neonatal Behavioral Assessment Scale (NBAS). Infants receiving KC showed a more rapid maturation of vagal tone between 32 and 37 weeks' GA (p=0.029). More rapid improvement in state organization was observed in KC infants, in terms of longer periods of quiet sleep (p=0.016) and alert wakefulness (p=0.013) and shorter periods of active sleep (p=0.023). Neurodevelopmental profile was more mature for KC infants, particularly habituation (p=0.032) and orientation (p=0.007). Results underscore the role of early skin-to-skin contact in the maturation of the autonomic and circadian systems in preterm infants.

trans and cis Splicing in Trypanosomatids: Mechanism, Factors, and Regulation

Abstract: mRNA maturation in trypanosomes differs from the process in most eukaryotes mainly because protein-coding genes are transcribed into polycistronic RNAs in this organism ([78][1]). Studies from the ongoing genome project suggest that the entire chromosome may be transcribed as large transcripts, but

Linguistic distance and initial reading acquisition: The case of Arabic diglossia

Abstract: The study examined phonemic awareness and pseudoword decoding in kindergarten and first grade Arabic native children. Because native speakers of Arabic first learn to read in Modern Standard Arabic (MSA), a language structurally distinct from the local form of the language they grow up speaking, it was hypothesized that the linguistic differences between the two varieties, the so-called diglossic variables, would interfere with the acquisition of basic reading processes in MSA. Two diglossic variables were examined: phoneme and word syllabic structure. The children's phoneme isolation and pseudoword decoding skills were tested. The results showed that both diglossic variables interfered with the children's performance of both tasks in both grades. The findings support the role of linguistic distance in the acquisition of basic reading processes in a diglossic context.

Core−Shell Nanoporous Electrode for Dye Sensitized Solar Cells: the Effect of the SrTiO3 Shell on the Electronic Properties of the TiO2 Core

Abstract: A nanoporous TiO2 electrode coated with a thin SrTiO3 layer was synthesized for photoelectrochemical applications. Introduction of this core−shell electrode to a dye sensitized solar cell increased the open circuit photovoltage while reducing the short circuit photocurrent in comparison with a cell containing the standard noncoated TiO2 electrode. The photovoltage increases is more significant than the photocurrent reduction resulting in a 15% improvement of the overall conversion efficiency of the solar cell. The performance of the TiO2−SrTiO3 core−shell electrode in the dye sensitized solar cell was analyzed by several methods including photocurrent−voltage correlation, spectro-electrochemistry, dark current measurement, IPCE, and photovoltage spectroscopy. The results indicate that the SrTiO3 layer shifts the conduction band of the TiO2 in the negative direction rather than forming energy barrier at the TiO2/electrolyte interface as found for similar coating by other materials. The shift of the TiO2 ba...

Nonaqueous magnesium electrochemistry and its application in secondary batteries.

Abstract: A revolution in modern electronics has led to the miniaturization and evolution of many portable devices, such as cellular telephones and laptop computers, since the 1980s. This has led to an increasing demand for new and compatible energy storage technologies. Furthermore, a growing awareness of pollution issues has provided a strong impetus for the science and technology community to develop alternatives with ever-higher energy densities, with the ultimate goal of being able to propel electric vehicles. Magnesium's thermodynamic properties make this metal a natural candidate for utilization as an anode in high-energy-density, rechargeable battery systems. We report herein on the results of extensive studies on magnesium anodes and magnesium insertion electrodes in nonaqueous electrolyte solutions. Novel, rechargeable nonaqueous magnesium battery systems were developed based on the research. This work had two major challenges: one was to develop electrolyte solutions with especially high anodic stability in which magnesium anodes can function at a high level of cycling efficiency; the other was to develop a cathode that can reversibly intercalate Mg ions in these electrolyte systems. The new magnesium batteries consist of Mg metal anodes, an electrolyte with a general structure of Mg(AlX(3-n)R(n)R')(2) (R',R = alkyl groups, X = halide) in ethereal solutions (e.g., tetrahydrofuran, polyethers of the "glyme" family), and Chevrel phases of MgMo(3)S(4) stoichiometry as highly reversible cathodes. With their practical energy density expected to be >60 Wh/Kg, the battery systems can be cycled thousands of times with almost no capacity fading. The batteries are an environmentally friendly alternative to lead-acid and nickel-cadmium batteries and are composed of abundant, inexpensive, and nonpoisonous materials. The batteries are expected to provide superior results in large devices that require high-energy density, high cycle life, a high degree of safety, and low-cost components. Further developments in this field are in active progress.

Emotional prejudice, essentialism, and nationalism - The 2002 Tajfel lecture

Abstract: In explaining differences between groups, people ascribe the human essence to their ingroup and consider outgroups as less human. This phenomenon, called infra-humanization, occurs outside people's awareness. Because secondary emotions (e.g. love, hope, contempt, resentment) are considered uniquely human emotions, people not only attribute more secondary emotions to their ingroup than to outgroups, but are reluctant to associate these emotions with outgroups. Moreover, people behave less cooperatively (in terms of altruism, imitation, and approach) with an outgroup member who expresses himself through secondary emotions. Infra-humanization occurs for high and low status groups, even in the absence of conflict between groups. It does not occur when the outgroup target is adequately individualized, by a complete name or through perspective taking, for instance.

Public Finance and Public Policy: Responsibilities and Limitations of Government

Abstract: The second edition of Public Finance and Public Policy retains the first edition's themes of investigation of responsibilities and limitations of government. The present edition has been rewritten and restructured. Public choice and political economy concepts and political and bureaucratic principal-agent problems are introduced at the beginning for application to later topics. Fairness, envy, hyperbolic discounting, and other concepts of behavioral economics are integrated throughout. The consequences of asymmetric information and the tradeoff between efficiency and ex-post equality are recurring themes. Key themes investigated are markets and governments, institutions and governance, public goods, public finance for public goods, market corrections (externalities and paternalist public policies), voting, social justice, entitlements and equality of opportunity, choice of taxation, and the need for government. The purpose of the book is to provide an accessible introduction to the use of public finance and public policy to improve on market outcomes.

Attachment theory and group processes: the association between attachment style and group-related representations, goals, memories, and functioning.

Abstract: Four studies examined attachment-style differences in group-related cognitions and behaviors. In Studies 1-2, participants completed scales on group-related cognitions and emotions. In Studies 3-4, participants were divided into small groups, and their performance in group tasks as well as the cohesion of their group were assessed. Both attachment anxiety and avoidance in close relationships were associated with negative group-related cognitions and emotions. Anxiety was also related to the pursuit of closeness goals and impaired instrumental performance in group tasks. Avoidance was related to the pursuit of distance goals and deficits in socioemotional and instrumental performance. Group cohesion significantly moderated the effects of attachment anxiety. The discussion emphasizes the relevance of attachment theory within group contexts.

Testing a family intervention hypothesis: the contribution of mother-infant skin-to-skin contact (kangaroo care) to family interaction, proximity, and touch

Abstract: The provision of maternal-infant body contact during a period of maternal separation was examined for its effects on parent-infant and triadic interactions. Participants were 146 three-month-old preterm infants and their parents, half of whom received skin-to-skin contact, or kangaroo care (KC), in the neonatal nursery. Global relational style and micro-patterns of proximity and touch were coded. Following KC, mothers and fathers were more sensitive and less intrusive, infants showed less negative affect, and family style was more cohesive. Among KC families, maternal and paternal affectionate touch of infant and spouse was more frequent, spouses remained in closer proximity, and infant proximity position was conducive to mutual gaze and touch during triadic play. The role of touch as a constituent of the co-regulatory parent-infant and triadic systems and the effects of maternal contact on mothering, co-parenting, and family processes are discussed.

Toddlers' self-regulated compliance to mothers, caregivers, and fathers: implications for theories of socialization.

Abstract: To compare children's socialized behavior to parents and nonparental agents, this study examined self-regulated compliance to mothers and caregivers--an early form of internalization--in 90 toddlers, half of whom were also observed with fathers. Adults were observed in play, teaching, and discipline sessions with the child and were interviewed on child-rearing philosophies. Child cognition and emotion regulation were assessed, and naturalistic observations were conducted at child-care locations. Mean-level and rank-order stability were found in child compliance to the 3 adults. Child emotion regulation and adult warm control in a discipline situation were related to self-regulated compliance to the mother, caregiver, and father. Compliance to parents correlated with parental sensitivity and philosophies, and compliance to the caregiver correlated with child cognition and social involvement when child-care quality was controlled. Maternal sensitivity and warm control discipline predicted compliance to the caregiver but not vice versa. Results are consistent with theoretical positions on the generalization of socialization from the mother to nonmaternal agents.

Remodeling of the Actin Cytoskeleton During Mammalian Sperm Capacitation and Acrosome Reaction

Abstract: The sperm acrosome reaction and penetration of the egg follow zona pellucida binding only if the sperm has previously undergone the poorly understood maturation process known as capacitation. We demonstrate here that in vitro capacitation of bull, ram, mouse, and human sperm was accompanied by a time-dependent increase in actin polymerization. Induction of the acrosome reaction in capacitated cells initiated fast F-actin breakdown. Incubation of sperm in media lacking BSA or methyl-b-cyclodextrin, Ca21, or NaHCO3, components that are all required for capacitation, prevented actin polymerization as well as capacitation, as assessed by the ability of the cells to undergo the acrosome reaction. Inhibition of F-actin formation by cytochalasin D blocked sperm capacitation and reduced the in vitro fertilization rate of metaphase II-arrested mouse eggs. It has been suggested that protein tyrosine phosphorylation may represent an important regulatory pathway that is associated with sperm capacitation. We show here that factors known to stimulate sperm protein tyrosine phosphorylation (i.e., NaHCO3, cAMP, epidermal growth factor, H2O2, and sodium vanadate) were able to enhance actin polymerization, whereas inhibition of tyrosine kinases prevented F-actin formation. These data suggest that actin polymerization may represent an important regulatory pathway in with sperm capacitation, whereas F-actin breakdown occurs before the acrosome reaction. acrosome reaction, gamete biology, in vitro fertilization, sperm, sperm capacitation

Thermotaxis of mammalian sperm cells: A potential navigation mechanism in the female genital tract

Abstract: Thermotaxis of mammalian sperm cells: A potential navigation mechanism in the female genital tract