Loneliness before and after COVID-19: Sense of Coherence and Hope as Coping Mechanisms

The COVID-19 pandemic posed a major threat to public health, with long-lasting consequences for the daily habits and practices of people around the world. The combination of hazardous health conditions and extensive changes to people's daily routines due to lockdowns, social restrictions, and employment uncertainty have led to mental health challenges, reduced levels of subjective wellbeing, and increased maladaptive behaviors and emotional distress. Nevertheless, some studies have reported increased adaptive functioning and resilience after the pandemic, suggesting a more complex pattern of effects. The goals of the current study were to explore the role of two coping variables, sense of coherence and hope, in people's emotional wellbeing and adaptation in dealing with loneliness before and after such a stressful period. In a cross-sectional study, 974 Israeli participants (sample 1: 540 participants before the pandemic; sample 2: 434 participants after the pandemic restrictions) answered online questionnaires about their loneliness, hope and sense of coherence levels before and after the pandemic. While the two groups did not differ in their levels of hope, the participants in the group before COVID-19 reported lower levels of loneliness and sense of coherence. However, the results also indicated that although the COVID-19 pandemic was related to increased levels of loneliness, the participants' sense of coherence mediated this increase and their levels of hope moderated it. The theoretical contribution of these findings is discussed, as well as interventional implications and future directions.

Post-traumatic Growth: The Roles of the Sense of Entitlement, Gratitude and hope

People believe that they are entitled to well-being and safety, and their responses to unexpected traumatic events reveal individual differences. Their reactions vary, from feeling blocked and distressed to feeling proactive towards new growth, depending on their personal resources. The current study sought to identify the role of entitlement in explaining post-traumatic growth (PTG) while considering the role of gratitude and hope as personal resources. We used a community-based sample of Israeli adults (n = 182) who reported experiencing a traumatic event during the preceding year. The relationships between PTG and their sense of entitlement, gratitude, and hope were examined. A stepwise multiple hierarchical regression revealed that all the three variables were associated with PTG. However, the effect of hope turned insignificant with the inclusion of sense of entitlement and gratitude in the regression. Sense of entitlement and gratitude were independently associated with PTG. The theoretical contribution of these findings is discussed, as well as their interventional implications and future directions.

The hope theory and specific learning disorders and/or attention deficit disorders (SLD/ADHD): Developmental perspectives

Research on disabilities has generally used a deficit-oriented approach. However, the recent appreciation of the personal strengths and positive traits of the disabled has raised awareness of them as empowering and activating factors. According to the hope theory, the ability to embrace future perspectives, set meaningful goals, and plan specific paths to reach these goals predict well-being and adjustment. We review the research on the role of hope in the lives of individuals with SLD/ADHD from a developmental perspective. We investigate hope as a resource in predicting these people's ability to deal with personal risks through developmental stages and contextual conditions. We conclude by proposing future research and intervention directions.

Social participation and posttraumatic growth: The serial mediation of hope, social support, and reappraisal

In light of the global crisis created by the outbreak of the coronavirus and the disease it causes, coronavirus disease 2019, the goal of the study was to detect factors that might enhance people's ability to experience positive psychological change during traumatic events. As such, this study examined the relationship between social participation and posttraumatic growth (PTG) during the coronavirus outbreak and tested the mediating role of hope, social support, and cognitive reappraisal in explaining this relationship. The sample consisted of 275 participants (21.8% male, and 78.2% female, with an average age of 33.42, SD = 13.63), subjected to social-distancing regulations during this period. Results demonstrated a serial mediation model in which social participation predicted PTG directly and indirectly through hope (pathways and agency), social support, and cognitive reappraisal. The importance of social participation in nourishing personal resources and practical implications including the need for prevention programs are discussed.

Learning Difficulties and Loneliness in College and Beyond: The Mediating Role of Self-Efficacy, Proactive Coping, and Hope

Following the conservation of resources, social-cognitive and hope theories, the goals of this study were to identify the role of self-efficacy, proactive coping, and hope as mediators in the relations between learning difficulties and loneliness distress. A questionnaire was sent to current and past students. The sample consisted of 498 participants. The results demonstrated that individuals with learning difficulties reported higher levels of loneliness compared with individuals without learning difficulties. Moreover, self-efficacy, proactive coping, and hope mediated the relations between levels of learning difficulties and loneliness. Specifically, the final model emphasized the important role of hopeful beliefs, since hope mediated the relations between learning difficulties, self-efficacy, and proactive coping with loneliness. In terms of practical implications, professionals' awareness as well as psychoeducational programs could be tailor-made to enhance hopeful beliefs and reduce loneliness.

Perceived social support, loneliness, and hope during the COVID-19 Pandemic: Testing a mediating model in the UK, USA, and Israel

Objectives

The COVID‐19 epidemic is affecting the entire world and hence provides an opportunity examine how people from different countries engage in hopeful thinking. The aim of this study was to examine the potentially facilitating role of perceived social support vis‐à‐vis hope as well as the mediating role of loneliness between perceived social support and hope. This mediating model was tested concurrently in the UK, the USA, and Israel.

Methods

In April 2020, as the first wave of the virus struck the three aforementioned countries, we assessed perceived social support, loneliness, and hope in 400 adults per country (N = 1,200). Assessments in the UK/USA were conducted via the Prolific platform, whereas in Israel they were conducted via Facebook/WhatsApp.

Results

In all three countries, perceived social support predicted elevated hope, although the effect was smallest in the UK. Loneliness mediated this effect in all three countries, although full mediation was attained only in the UK.

Conclusions

Perceived social support may facilitate hope in dire times, possibly through the reduction of loneliness.

Practitioner Points

Findings are consistent with respect to the potentially protective role of perceived social support vis‐à‐vis hope.

Perceived social support may increase hope through decreasing loneliness.

In the UK, the above‐noted mediating effect of loneliness appears to be stronger than in Israel and the USA.

Elevated levels of perceived social support should serve as a desired outcome in individual and group psychotherapy, as well as in community based interventions.

Does Family Cohesion Predict Children's Effort? The Mediating Roles of Sense of Coherence, Hope, and Loneliness

The degree of cohesion and support within families has often been considered a predictor of students' effort-investment and success in school. The objectives of this study are to examine the roles of personal factors (i.e., sense of coherence and hopeful thinking) as well as interpersonal factors (i.e., loneliness) in mediating the relationship between family cohesion and effort. The sample consists of 1719 elementary school children (781 boys and 938 girls) from the fifth and six grades (mean age = 10.25, SD = 0.70) of 29 elementary schools in central Israel. Students answered study questionnaires in the middle of their academic year. Analyses utilizing hierarchical multiple regression and Hayes' bootstrapping approach (PROCESS; Preacher & Hayes, 2008) were used. The results support the distinctive contribution of family cohesion and the mediating roles of sense of coherence and hope (as protective factors) as well as loneliness (as a risk factor) in predicting students' school effort. This study has important educational implications, emphasizing the value of promoting hopeful thinking and coping with loneliness in helping students to thrive in their studies.

Learning Disabilities and Social Environments: Kibbutz versus City Comparisons of Loneliness and Social Competence

In order to explore aspects of loneliness and social competence of learning disabled students in relation to specific environmental contexts, this study focused on children in two different social systems: a kibbutz and a city. The aim of the study was to investigate the social skills and loneliness patterns among 122 students with learning disabilities (LD) in self-contained special classes within regular school systems (66 kibbutz students; 56 city students) and among 120 nondisabled (nonLD) students within these same environmental conditions (69 kibbutz students; 51 city students). A four-way MANCOVA (LD/nonLD X kibbutz/city X male/female X lower/higher grades, with age as covariate) was performed for self-reported loneliness and empathy, peer-rated sociometric measures, teacher-rated social skills, and classroom adjustment as the dependent measures. LD youngsters were found to be less socially competent and more lonely than their nonLD peers in all social competence areas, and as assessed by three sources of information. When compared with LD city students, LD kibbutz students were evaluated by their teachers as demonstrating fewer maladaptive externalising behaviours, and by their peers as having more friends. Social contexts did not differentiate between the two LD groups' feeling of loneliness or rates of peer acceptance, and it can be concluded that students with LD were found to experience loneliness regardless of gender or environmental conditions.

The Therapeutic Class Teacher

The therapeutic class is an Israeli means of providing a back-up resource to enhance mainstreaming. The role of the therapeutic teacher is to improve emotional adjustment and act as an educational therapist. Fifty-five therapeutic class teachers in 42 regular schools participated in the study, in the attempt to define the role. They expressed role conflict in structured interviews. Their principals and school psychologists expected them to act as educational therapists, but the therapeutic class teachers themselves expressed confusion between the role expected of them as therapists and the need to be more involved in teaching. The more experienced of them tended to evaluate their therapeutic work as more successful.

Loneliness, Mindfulness, and Academic Achievements: A Moderation Effect among First-Year College Students

The transition to college enhances feelings of loneliness, and lonely students typically underperform academically due to the depletion of cognitive resources. Mindfulness practice has been demonstrated to improve certain cognitive abilities. The current study examined whether mindfulness practice may moderate the relations between perceived loneliness and academic performance. In this study we combined data from two separate studies. In the first, loneliness, optimism, and academic self-efficacy were measured at the beginning of the academic year. In the second, mindfulness workshops were conducted in order to examine their impact on memory performance. In all, 73 college students in their first semester participated in the conjoint study (N = 50 mindfulness practice and N = 23 control). Their grades at the end of the semester and at the end of the year were also collected. Regression analyses were conducted in order to examine whether mindfulness moderated the effect of loneliness on academic achievements, and revealed that: a) loneliness was negatively correlated with recognition memory performance and with grades; b) grades were higher in the mindfulness group than in the control group; c) mindfulness and loneliness interacted, such that loneliness negatively predicted academic grades only for students who did not practice mindfulness. The results suggested that mindfulness practice may reduce the outcomes of loneliness on academic achievements in the first year of college.

Socioemotional self-perceptions, family climate, and hopeful thinking among students with learning disabilities and typically achieving students from the same classes

This study aimed at examining the adjustment of students with learning disabilities (LD) and at exploring the mediating role of hope. By means of a multidimensional approach, the interactions between risk and protective factors emerging from internal and external resources among 856 high school students (10th to 12th grades) were analyzed. A total of 529 typically achieving students and 327 students with LD attending general education classes in seven high schools completed seven instruments measuring sense of coherence, basic psychological needs, loneliness, family climate, hope, academic self-efficacy, and effort. The students' achievements in English, history, and mathematics were collected. The analysis used structural equation modeling, and the results emphasized the significant role of hope as a mediator between risk and protective factors and academic self-efficacy and its significance for students with and without LD in explaining achievements and effort investment.

A focused intervention for 1st-year college students: promoting hope, sense of coherence, and self-efficacy

Many students experience elevated psychological distress during their 1st year at college. Within the salutogenic paradigm (A. Antonovsky, 1987), sense of coherence (SOC), self-efficacy, and hope (in terms of hope theory; C. R. Snyder, 2002) are considered as protective factors in the demanding academic system. Study goals were to examine the outcomes of a focused workshop for 43 students, targeting the promotion of hope, sense of coherence, and self-efficacy for enhancing students' academic adjustment as expressed through their grades. Results revealed an effect over the 3 measurement time-points (before the workshop, immediately after it, and after 1 month), as well as the interactions of time and hope levels. Although their mean grades were not statistically different before the intervention, students who achieved higher levels of hope following the workshop got higher grades in the semester following the intervention. SOC and self-efficacy scores were significantly related both to hope levels after 1 month and to mean grades. The implications of this study for promoting a hopeful orientation in educational systems are discussed, and future interventional research is suggested.

Involvement of the prostate and testis expression (PATE)-like proteins in sperm-oocyte interaction

BACKGROUND

The prostate and testis expression (PATE)-like family of proteins are expressed mainly in the male genital tract. They are localized in the sperm head and are homologous to SP-10, the acrosomal vesicle protein also named ACRV1. Our aim was to characterize the expression and functional role of three PATE-like proteins in the testis and ejaculated sperm.

METHODS

The expression and localization of PATE-like proteins in human testis biopsies (n= 95) and sperm cells were assessed by RT-PCR, immunohistochemistry and immunofluorescence staining (at least 600 sperm cells per specimen). The function of the PATE protein was tested by the hemizona assay and hamster egg penetration test (HEPT).

RESULTS

PATE and PATE-M genes and proteins were present almost exclusively in germ cells in the testis: immunoflourescence showed that the percentage of germ cells positive for PATE, PATE-M and PATE-B was 85, 50 and 2%, respectively. PATE and PATE-M proteins were localized in the equatorial segment of the sperm head, while PATE-B protein was localized in the post-acrosomal region. A polyclonal antibody (Ab, at 1:50 and 1:200 dilutions) against the PATE protein did not inhibit sperm-zona binding in the hemizona assay (hemizona index of 89.6 ± 10 and 87 ± 36%, respectively). However, there was inhibition of sperm-oolemma fusion and penetration in the HEPT (penetration index: without Ab 7 ± 3.9; Ab dilution of 1:100, 4 ± 3.5; Ab dilution of 1:20, 0.6 ± 1.2, P < 0.001).

CONCLUSIONS

Our data suggest that PATE protein is involved in sperm-oolemma fusion and penetration but not sperm-zona binding.

Children's loneliness, sense of coherence, family climate, and hope: developmental risk and protective factors

The study examined the contributions of individual and familial variables for the prediction of loneliness as a developmental risk and the sense of coherence as a protective factor. The sample consisted of 287 children from grades 5-6. Their loneliness, sense of coherence, hope, effort, and family climate were assessed. Separate hierarchical multiple regression analyses revealed that family cohesion and children's hope contributed to the explanation of the risk and protective outcomes. Yet, the contribution of the family adaptability was not significant. Cluster analysis of the family climate dimensions (i.e., cohesion and adaptability) was performed to clarify the interactive roles of family adaptability together with family cohesion. The authors identified 4 separate family profiles: Children in the 2 cohesive families' clusters (Cohesive Structured Families and Cohesive Adaptable Families) reported the lowest levels of loneliness and the highest levels of personal strengths. Children within rigid and noncohesive family cluster reported the highest levels of loneliness and the lowest levels of children's sense of coherence. The unique role of the family flexibility within nonsupportive family systems was demonstrated. The results further clarified the unique profiles' characteristics of the different family clusters and their adjustment indexes in terms of loneliness and personal strengths.

The mediating role of internet connection, virtual friends, and mood in predicting loneliness among students with and without learning disabilities in different educational environments

This study evaluated a multidimensional model of loneliness as related to risk and protective factors among adolescents with learning disabilities (LD). The authors aimed to identify factors that mediated loneliness among 716 adolescents in Grades 10 through 12 who were studying in high schools or in Youth Education Centers for at-risk populations. There were 334 students with LD, divided into subgroups according to disability severity (three levels of testing accommodations), and 382 students without LD. Five instruments measured participants' socioemotional characteristics: loneliness, Internet communication, mood, and social and academic achievement-oriented motivation. Using structural equation modeling, the results confirmed the loneliness model and revealed that the use of the Internet to support interpersonal communication with friends predicted less intense loneliness, whereas virtual friendships with individuals whom students knew only online predicted greater loneliness. Positive and negative mood and motivation also predicted students' loneliness. In addition, the severity of LD predicted stronger loneliness feelings.

Beta-glucosylceramide: a novel method for enhancement of natural killer T lymphoycte plasticity in murine models of immune-mediated disorders

BACKGROUND

beta-Glucosylceramide, a naturally occurring glycolipid, exerts modulatory effects on natural killer T (NKT) lymphocytes.

AIM

To determine whether beta-glucosylceramide can alter NKT function in opposite directions, colitis was induced by intracolonic installation of trinitrobenzenesulphonic acid, and hepatocellular carcinoma (HCC) was induced by transplantation of Hep3B cells.

METHODS

The immunological effect of beta-glucosylceramide was assessed by analysis of intrahepatic and intrasplenic lymphocyte populations, serum cytokines and STAT protein expression.

RESULTS

Administration of beta-glucosylceramide led to alleviation of colitis and to suppression of HCC, manifested by improved survival and decreased tumour volume. The beneficial effects were associated with an opposite immunological effect in the two models: the peripheral:intrahepatic CD4:CD8 lymphocyte ratio increased in the colitis model and decreased in the HCC group. The peripheral:intrahepatic NKT lymphocyte ratio decreased in beta-glucosylceramide-treated mice solely in the HCC model. The effect of beta-glucosylceramide was associated with decreased STAT1 and 4 expression, and with overexpression of STAT6, along with decreased interferon gamma levels in the colitis model, whereas an opposite effect was noted in the HCC model.

CONCLUSIONS

beta-glucosylceramide alleviates immunologically incongruous disorders and may be associated with "fine tuning" of immune responses, by changes in plasticity of NKT lymphocytes.

Comparisons of achievement, effort, and self-perceptions among students with learning disabilities and their peers from different achievement groups

This study compared the social-emotional implications of academic achievement for students with and without learning disabilities (LD) and identified predictors of effort investment. Students with LD showed lower levels of achievement, effort investment, academic self-efficacy, sense of coherence, positive mood, and hope, and higher levels of loneliness and negative mood. When compared to peers without LD (n = 447) at four different academic achievement levels, students with LD showed higher achievement than the low-average group, but their social-emotional profiles were similar to the low and low-average groups. Hierarchical multiple regression analysis showed that achievement, academic self-efficacy, negative mood, and hope predicted effort investment for students with LD. These results demonstrated the importance of hope in understanding the functioning of students with LD.

Adoptive transfer of regulatory NKT lymphocytes ameliorates non-alcoholic steatohepatitis and glucose intolerance in ob/ob mice and is associated with intrahepatic CD8 trapping

The aim of this study was to determine the effect of adoptive transfer of regulatory natural killer T (NKT) lymphocytes on the metabolic disorder in leptin-deficient ob/ob mice, which feature depletion and defective function of NKT and CD4 lymphocytes. Leptin-deficient ob/ob mice were subjected to transplantation of 1 x 10(6) of either ob/ob or wild-type-derived NKT lymphocytes, or to transplantation of either ob/ob or wild-type-derived splenocytes. The effect on hepatic fat content was measured by magnetic resonance imaging (signal intensity index) and histology, using the steatohepatitis grading scale. The degree of glucose intolerance was measured by an oral glucose tolerance test (GTT). Adoptive transfer of wild-type or ob/ob-derived regulatory NKT cells led to a 12% decrease in hepatic fat content. A significant histological shift from macrosteatosis to microsteatosis was observed. Marked improvement in the GTT was noted in wild-type or ob/ob-derived NKT recipients. Metabolic effects were associated with a significant decrease in peripheral and intrahepatic CD4/CD8 lymphocyte ratios. Intrahepatic CD8 trapping was observed in all responders. Serum interleukin 10 levels decreased significantly. In conclusion, adoptive transfer of a relatively small number of regulatory NKT lymphocytes into ob/ob mice results in a significant reduction in hepatic fat content, a shift from macro to microsteatosis, and significant improvement in glucose intolerance. These effects were associated with decreased peripheral and intrahepatic CD4/CD8 ratios and decreased interleukin 10 levels. The results further support a role for regulatory NKT lymphocytes in the pathogenesis of non-alcoholic steatohepatitis in the leptin-deficient murine model.

Adoptive transfer of small numbers of DX5+ cells alleviates graft-versus-host disease in a murine model of semiallogeneic bone marrow transplantation: a potential role for NKT lymphocytes

Natural killer T (NKT) lymphocyte cells are a subset of regulatory lymphocytes with important immunemodulatory effects. Our aim was to evaluate the effect of transplantation of NKT lymphocytes on graft versus host disease (GVHD) in a murine model of semiallogeneic BMT. GVHD was generated by infusion of 2 x 107 splenocytes from C57BL/6 donor mice into irradiated (C57BL/6 x Balb/c)F1 recipient mice. Adoptive transfer of increasing numbers of DX5+ cells was performed. Recipient mice were followed for histological parameters of GVHD-associated liver, bowel, and cutaneous injury. Intrahepatic and intrasplenic lymphocytes were isolated and analyzed by FACS for CD4+ and CD8+ subpopulations. It was seen that adoptive transfer of 4.5 x 106 DX5+ cells significantly alleviated GVHD-related hepatic, bowel, and cutaneous injury, and improved survival (85% survival on day 28). In contrast, depletion of DX5+ cells led to severe GVHD-associated multiorgan injury and 100% mortality. A direct correlation with the number of transplanted DX5+ cells was noted (maximal effect with transplantation of 4.5 x 106 DX5+ cells). Tolerance induction was associated with an increased peripheral CD4/CD8 ratio, intrahepatic trapping of CD8 lymphocytes and a shift towards a Th2-type cytokine profile, manifested by decreased IL-12/IL10, IL-12/IL-4, IFNgamma/IL-10, and IFNgamma/IL-4 ratios. Transplantation of DX5+ cells holds promise as a novel therapeutic measure for GVHD.

[Cholangiocarcinoma in primary sclerosing cholangitis: "chronicle of a death foretold"?]

Primary sclerosing cholangitis (PSC), a condition usually associated with inflammatory bowel disease, is a chronic inflammatory state of the biliary tract characterized by fibrotic strictures of intrahepatic and extrahepatic bile ducts. Between 5-15% of patients with PSC will develop cholangiocarcinoma. The diagnosis of cholangiocarcinoma in patients with PSC is difficult, as it is often impossible to distinguish benign PSC-related strictures from lesions associated with cholangiocarcinoma. Consequently, most patients are diagnosed with advanced disease and have a dismal prognosis at the time of diagnosis. The importance of characterizing patients with PSC who have an increased risk of developing cholangiocarcinoma and of developing means for early detection of this disease cannot be over-emphasized. Detection of cholangiocarcinoma in asymptomatic patients is additionally important, as this condition is considered a contraindication for liver transplantation. We describe a patient with longstanding Crohn's disease and PSC who developed cholangiocarcinoma, and review the literature regarding risk factors for cholangiocarcinoma, early detection of cholangiocarcinoma and the significance of existing cholangiocarcinoma in the context of liver transplantation.

Enzyme replacement therapy in the management of longstanding skeletal and soft tissue salmonella infection in a patient with Gaucher's disease

A splenectomised patient with Gaucher's disease who developed multiple foci of osteomyelitis and soft tissue abcesses, after a severe episode of group C salmonella sepsis, is described. Aggressive antibiotic treatment and surgical drainage had little effect and the patient's condition continued to deteriorate. With initiation of enzyme replacement therapy (ERT) in addition to specific antibiotic treatment, defervescence and gradual healing occurred. Complete resolution of the infection was seen after 15 months. The possible role of ERT in healing bacterial infections in Gaucher's disease is discussed.

Effect of ozone on neutrophil function in vitro

The application of ozone is widely practised as a form of alternative medicine, particularly in Germany and Eastern Europe. Ozone major autohemotherapy (the return of a small amount of a patient's blood to the circulation after ex vivo exposure to ozone) has been reported to have a therapeutic effect in various pathological conditions, including ischemic, infectious, autoimmune and neoplastic disorders. Ozone has an effect on the expression of cytokines, adhesion molecules and acute phase reactants, which are responsible in part for the respiratory inflammatory response observed after exposure to this gas. The purpose of the present study was to investigate the effect of ozone administration ex vivo, at a concentration commonly used in major autohemotherapy, on peripheral blood neutrophil function in vitro. Blood drawn from healthy volunteers was studied for neutrophil adhesion, chemotaxis and O-2 production before and after exposure to 30 microg/ml ozone. There was no significant difference in adhesion and chemotaxis of neutrophils exposed to ozone versus unexposed cells. O-2 production was minimally decreased (20.3 +/- 5.0 vs. 22.1 +/- 5.5 nmol/106 cells/10 min, respectively; P=0.01), a reduction of no clinical significance. This study confirms that major autohemotherapy with ozone is safe as far as neutrophil function is concerned. Combined with previous data, it seems that well-designed clinical trials to assess the efficacy of major autohemotherapy would pose no danger to blood cell populations, and should be encouraged.

Photon statistics of amplified spontaneous emission noise in a 10-Gbit/s optically preamplified direct-detection receiver

We verify experimentally, over a dynamic range of 55 dB in the probability distribution, that the amplified spontaneous emission noise of the 0's from an optically preamplified receiver is degenerate Bose-Einstein distributed. Using the noise parameters extracted from the experiment, we are able to predict the sensitivity of a 10-Gbit/s direct-detection receiver.

Loneliness and coherence among preschool children with learning disabilities

This study investigated loneliness and coherence among Israeli preschool children with learning disabilities, in an attempt to identify the sources of social deficits before academic failure was established. The sample consisted of 187 preschool children divided into three groups: (a) 60 children at high risk for developing learning disabilities (LD) in six mainstreamed preschool settings (47 boys and 13 girls), (b) 76 nonhandicapped peers from the same preschools (56 boys and 20 girls), and (c) 51 children (38 boys and 13 girls) at high risk for developing LD who were regular students at 17 preschools and received special help in the afternoons outside their educational settings, at a regional learning center for students with LD. The research instruments consisted of the Children's Sense of Coherence Scale, the Loneliness Scale, a peer nomination procedure, and teachers' ratings. Two-way MANOVAs demonstrated that the two groups of children (Groups [A] and [C]) with LD and with a high risk for developing learning disabilities experienced higher levels of loneliness and lower levels of coherence. A subgroup examination revealed that they were less accepted by nondisabled peers and had less reciprocal nominations. Furthermore, their teachers viewed them as showing more maladjustment.

Cross phase modulation squeezing in optical fibers

A novel method of producing squeezed vacuum uses cross phase modulation between a linearly polarized pump signal and the orthogonal polarized vacuum. Here we report on such cross phase modulation using 1-nJ 150-fs pulses from a low noise stretched pulse laser. The nonlinear medium was a single mode fiber and the noise reduction was 3 dB.

Direct measurement of self-phase shift due to fiber nonlinearity

We directly measure the time-independent nonlinear self-phase shift of a pulse after fiber propagation by spectral interferometry. Both the soliton and the nonsoliton case were studied. We verify numerically that the measured phase shift approximates this time-independent phase well.

Self-switching of optical pulses in dispersion-imbalanced nonlinear loop mirrors

We report a novel nonlinear filter that transmits and shortens incident pulses while rejecting cw background as well as resonant continuum. A relative extinction of 22dB is reported for the cw background.

Synchronized two-color operation of a passively mode-locked erbium-doped fiber laser by dual injection locking

The recently introduced harmonic injection locking is a method for generating pulse trains at high repetition rates from passively mode-locked lasers. We report the simultaneous injection locking of two spectral bands in an erbium-doped fiber laser by injection of two spectrally distinct and temporally synchronized pulse trains. The injection-locked laser simultaneously produced pulses at wavelengths of 1.53 and 1.55 microm, each at a 7.5-GHz repetition rate and with a pulse width of 10 ps. We compared the experimental results with those of a passively mode-locked laser.

Noise reduction by harmonic injection locking of passively mode-locked erbium-doped fiber lasers

Harmonic injection locking can generate pulse trains at high repetition rates from passively mode-locked lasers. We have examined experimentally the mutual interaction of noise with the locking process. For injected signals with large timing and amplitude noise, the mode-locked fiber laser generated a pulse train with reduced noise. Injected signals with low timing and amplitude noise were employed for the reduction of the internal noise of the passively mode-locked laser. The achieved output pulse-to-pulse timing jitter in the range of 20-2500 Hz was ~0.6 ps, comparable with that of actively stabilized fiber lasers.

Injection locking of an actively mode-locked semiconductor laser

We report what is to our knowledge the first observation of synchronous coherent injection locking of an actively mode-locked extended cavity semiconductor laser to an external light pulse train. In the temporal domain, we observed experimentally and verified theoretically a significant narrowing of the output pulse of the mode-locked laser. In the spectral domain, we demonstrated experimentally the narrowing of the output optical spectrum that was due to rejection of spectral components outside the spectral band of the locking pulses. Locking ranges, in the time and the frequency domains, were measured to be ~200 ps and ~5 nm, respectively.

Social skills and classroom behavior among adolescents with mild mental retardation

Relations among self-reported social skills, teacher ratings of classroom behavior, and direct observations of social interactions among 87 adolescents with mild mental retardation were investigated and variables predicting the students' task orientation identified. Three information sources were employed. Results demonstrated that the four domains of social skills were related to the students' task orientation. The regression analysis revealed that students who were characterized by better social skills and fewer occurrences of hyperactivity and behavioral difficulties were viewed by teachers as evidencing more compliant and task-oriented behavior, implying their better ability to benefit from the special curriculum. The three sources of information validated one another and added information to the conceptualization and appraisal of social and academic competence among students with mental retardation.

Classification and validation of family climate subtypes in kibbutz fathers of disabled and nondisabled children

The aim of the study was to investigate the impact of disabled children on their fathers. Perceptions of family climate, sense of coherence, and satisfaction from family life were measured among 66 fathers of disabled children and among 74 fathers with nondisabled children in an Israeli kibbutz. The fathers of disabled children showed lower sense of coherence, derived less satisfaction from family life, and viewed their families as less encouraging of personal growth among family members. Four subtypes of family climate patterns, perceived by fathers of disabled children, were identified by cluster analysis and validated by the sense of coherence and global family satisfaction measures. Cluster analysis for the fathers of nondisabled children replicated the subtypes identified. The four subtypes were conceptualized as families with a (a) personal growth orientation, (b) conflict orientation, (c) conflict avoidance orientation, and (d) recreation avoidance orientation. Significant differences were found between the subtypes with regard to the family climate variables and satisfaction and coherence measures. Results demonstrated that different patterns of family climate characterized the two groups of fathers: In almost every cluster the measures of personal growth were lower for the fathers of disabled children.