Plasma irisin levels predict telomere length in healthy adults

The ageing process is strongly influenced by nutrient balance, such that modest calorie restriction (CR) extends lifespan in mammals. Irisin, a newly described hormone released from skeletal muscles after exercise, may induce CR-like effects by increasing adipose tissue energy expenditure. Using telomere length as a marker of ageing, this study investigates associations between body composition, plasma irisin levels and peripheral blood mononuclear cell telomere length in healthy, non-obese individuals. Segmental body composition (by bioimpedance), telomere length and plasma irisin levels were assessed in 81 healthy individuals (age 43∈±∈15.8 years, BMI 24.3∈±∈2.9 kg/m2). Data showed significant correlations between log-transformed relative telomere length and the following: age (p∈<∈0.001), height (p∈=∈0.045), total body fat percentage (p∈=∈0.031), abdominal fat percentage (p∈=∈0.038) , visceral fat level (p∈<∈0.001), plasma leptin (p∈=∈0.029) and plasma irisin (p∈=∈0.011), respectively. Multiple regression analysis using backward elimination revealed that relative telomere length can be predicted by age (b∈=∈-0.00735, p∈=∈0.001) and plasma irisin levels (b∈=∈0.04527, p∈=∈0.021). These data support the view that irisin may have a role in the modulation of both energy balance and the ageing process. © 2014 The Author(s).

Age-related macular degeneration is associated with increased vascular endothelial growth factor, hemorheology and endothelial dysfunction

OBJECTIVE: To investigate laboratory evidence of abnormal angiogenesis, hemorheologic factors, endothelial damage/dysfunction, and age-related macular degeneration (ARMD). DESIGN: Comparative cross-sectional study. PARTICIPANTS: We studied 78 subjects (26 men and 52 women; mean age 74 years; standard deviation [SD] 9.0) with ARMD attending a specialist referral clinic. Subjects were compared with 25 healthy controls (mean age, 71 years; SD, 11). INTERVENTION AND OUTCOME MEASURES: Levels of vascular endothelial growth factor (VEGF, an index of angiogenesis), hemorheologic factors (plasma viscosity, hematocrit, white cell count, hemoglobin, platelets), fibrinogen (an index of rheology and hemostasis), and von Willebrand factor (a marker of endothelial dysfunction) were measured. RESULTS: Median plasma VEGF (225 vs. 195 pg/ml, P = 0.019) and mean von Willebrand factor (124 vs. 99 IU/dl, P = 0.0004) were greater in ARMD subjects than the controls. Mean plasma fibrinogen and plasma viscosity levels were also higher in the subjects (both P < 0.0001). There were no significant differences in other indices between cases and controls. When "dry" (drusen, atrophy, n = 28) and "exudative" (n = 50) ARMD subjects were compared, there was no significant differences in VEGF, fibrinogen, viscosity, or von Willebrand factor levels. There were no significant correlations between the measured parameters. Stepwise multiple regression analysis did not demonstrate any significant clinical predictors (age, gender, smoking, body mass index, history of vascular disease, or hypertension) for plasma VEGF or fibrinogen levels, although smoking status was a predictor of plasma von Willebrand factor levels (P < 0.05). CONCLUSIONS: This study suggests an association between markers of angiogenesis (VEGF), hemorheologic factors, hemostasis, endothelial dysfunction, and ARMD. The interaction between abnormal angiogenesis and the components of Virchow's triad for thrombogenesis may in part contribute to the pathogenesis of ARMD.

A Computer Algebra Application to Determination of Lie Symmetries of Partial Differential Equations

The paper has been presented at the 12th International Conference on Applications of Computer Algebra, Varna, Bulgaria, June, 2006

"Belonging” in the gentrified Golden Horn/Halic neighbourhoods of Istanbul

Mainstream gentrification research predominantly examines experiences and motivations of the middle-class gentrifier groups, while overlooking experiences of non-gentrifying groups including the impact of in situ local processes on gentrification itself. In this paper, I discuss gentrification, neighbourhood belonging and spatial distribution of class in Istanbul by examining patterns of belonging both of gentrifiers and non-gentrifying groups in historic neighbourhoods of the Golden Horn/Halic. I use multiple correspondence analysis (MCA), a methodology rarely used in gentrification research, to explore social and symbolic borders between these two groups. I show how gentrification leads to spatial clustering by creating exclusionary practices and eroding social cohesion, and illuminate divisions that are inscribed into the physical space of the neighbourhood.

Association between body composition, circulating irisin and telomere length in healthy individuals and individuals with Type 2 diabetes

Aims: Obesity and Type 2 diabetes are associated with accelerated ageing. The underlying mechanisms behind this, however, are poorly understood. In this study, we investigated the association between circulating irisin - a novel my okine involved in energy regulation - and telomere length (TL) (a marker of aging) in healthy individuals and individuals with Type 2 diabetes. Methods: Eighty-two healthy people and 67 subjects with Type 2 diabetes were recruited to this cross-sectional study. Anthropometric measurements including body composition measured by biompedance were recorded. Plasma irisin was measured by ELISA on a fasted blood sample. Relative TL was determined using real-time PCR. Associations between anthropometric measures and irisin and TL were explored using Pearson’s bivariate correlations. Multiple regression was used to explore all the significant predictors of TL using backward elimination. Results: In healthy individuals chronological age was a strong negative predictor of TL (=0.552, p < 0.001). Multiple regression analysis using backward elimination (excluding age) revealed the greater relative TL could be predicted by greater total muscle mass(b = 0.046, p = 0.001), less visceral fat (b = =0.183, p < 0.001)and higher plasma irisin levels (b = 0.01, p = 0.027). There were no significant associations between chronological age, plasmairisin, anthropometric measures and TL in patients with Type 2diabetes (p > 0.1). Conclusion: These data support the view that body composition and plasma irisin may have a role in modulation of energy balance and the aging process in healthy individuals. This relationship is altered in individuals with Type 2 diabetes.

Body representation alterations in personal but not in extrapersonal neglect patients

There is still a matter of debate around the nature of personal neglect. Is it an attention disorder or a body representation disorder? Here we investigate the presence of body representation deficits (i.e., the visuo-spatial body map) in right and left brain-damaged patients and in particular in those affected by personal neglect. 23 unilateral brain-damaged patients (5 left-brain-damaged and 18 right-brain-damaged patients) and 15 healthy controls took part in the study. The visuo-spatial body map was assessed by means of the “Frontal body-evocation subtest (FBE),” in which participants have to put tiles representing body parts on a small wooden board where only the head is depicted as a reference point. In order to compare performance on the FBE with performance on an inanimate object that had well-defined right and left sides, participants also performed the “Car test.” Group statistical analysis shows that the performance of patients with personal neglect is significantly worse than that of the controls and patients without personal neglect in the FBE but not in the Car test. Single case analyses of the five patients with pure personal neglect confirm the results of group analysis. Our data supports the hypothesis that personal neglect is a pervasive body representation disorder.

Consequences of interorganizational information systems: An empirical investigation of the effects of EDI use on interorganizational relationships in the retail industry

This dissertation examines the consequences of Electronic Data Interchange (EDI) use on interorganizational relations (IR) in the retail industry. EDI is a type of interorganizational information system that facilitates the exchange of business documents in structured, machine processable form. The research model links EDI use and three IR dimensions--structural, behavioral, and outcome. Based on relevant literature from organizational theory and marketing channels, fourteen hypotheses were proposed for the relationships among EDI use and the three IR dimensions.^ Data were collected through self-administered questionnaires from key informants in 97 retail companies (19% response rate). The hypotheses were tested using multiple regression analysis. The analysis supports the following hypothesis: (a) EDI use is positively related to information intensity and formalization, (b) formalization is positively related to cooperation, (c) information intensity is positively related to cooperation, (d) conflict is negatively related to performance and satisfaction, (e) cooperation is positively related to performance, and (f) performance is positively related to satisfaction. The results support the general premise of the model that the relationship between EDI use and satisfaction among channel members has to be viewed within an interorganizational context.^ Research on EDI is still in a nascent stage. By identifying and testing relevant interorganizational variables, this study offers insights for practitioners managing boundary-spanning activities in organizations using or planning to use EDI. Further, the thesis provides avenues for future research aimed at understanding the consequences of this interorganizational information technology. ^

Factors associated with social work student satisfaction with field placements in child welfare

This study was conducted during the 1994-1995 academic year. Seven social work education programs in the state of Florida, all accredited by the Council on Social Work Education, participated in this study. Graduate and undergraduate social work students in child welfare field placements, and their field instructors, were surveyed during the Spring 1995 semester to assess their satisfaction with field placements in this area and the relationship of this satisfaction to employment interests and field placement recommendations.^ The majority of social work students responding to this survey were generally satisfied with several aspects of their field placements--the learning, field work program, field instructor, child welfare agency, and overall field experience. The field instructors were generally more satisfied than the students, but only statistically different from the students in the areas of satisfaction with the field work program and the child welfare agency. Multiple regression analysis revealed that learning assignment opportunities, field instructor relationship characteristics, placement preference, and pre-placement interview contributed to the prediction of student satisfaction.^ Student satisfaction in field placement was significantly related to the acceptance of employment, if offered, and the recommendation of the field placement to other students. Logistic regression analysis revealed that satisfaction with the child welfare agency was the greatest contributor to the prediction of acceptance of employment, and satisfaction with the field work program was the greatest contributor to the prediction of field placement recommendation. ^

A study of the relationship between parental self-efficacy and indicators of school involvement exhibited by Hispanic parents of elementary school children

The purpose of this study was to examine the relationship between Hispanic parents' sense of self-efficacy at various degrees of acculturation to the United States and specific indicators of school involvement in their elementary school children's education. It assessed the effects of acculturation on the level of parental self-efficacy and their degree of school involvement. The theoretical framework guiding this investigation was Bandura's theory of self-efficacy which advocates that the amount of effort a person devotes to the accomplishment of a specific outcome is related to a person's beliefs in their capabilities regardless of actual competencies.^ The research method involved a correlational design measuring levels of parental self-efficacy, acculturation, degree of school involvement and related demographic characteristics. Multiple regression analysis was performed to determine the degree of relationships existing between the predictor variables of self-efficacy and level of acculturation, and level of school involvement. The data was subjected to a path analysis to test the validity of the causal model advanced in this study specifying a positive relationship between the constructs of acculturation, parental self-efficacy and level of school involvement.^ A total of 109 Hispanic parents of students enrolled in five elementary public schools in Dade County, Florida, were selected for participation in the study. Results revealed a significant positive correlation r =.23, p $<$.05 between level of parental self-efficacy and number of hours parents spent helping their children with homework. A statistically significant positive correlation was found between acculturation and level of self-efficacy r =.21, p $<$.05. Statistically significant positive correlations were also found between acculturation and such indicators of parental school involvement as participation in parent-teacher conferences r =.20, p $<$.05, volunteering at school, r =.22, p $<$.05, attendance at school sponsored sports activities r =.26, p $<$.01, and volunteering in field-trips r =.28, p $<$.01.^ The multiple regression analysis equation predicting level of homework assistance provided by parents and self-efficacy was statistically significant, F(2,106) = 3.59, p $<$.03. The beta weights revealed that self-efficacy contributed the most to the prediction of homework assistance by parents, B =.258, p $<$.009. In turn, the variable of acculturation was the most significant predictor of number of school based parent involvement activities, B =.281, p $<$.05 level. The path analysis confirmed the results obtained in the multiple regression analyses, establishing self-efficacy as having a direct effect on the level of homework assistance provided by parents. Conversely, the variable of acculturation had a direct effect on the number of school based parent involvement activities. ^

Risk factors that predict maladaptive outcomes among sexually abused girls presenting for services at a community agency

The purpose of this study was to determine which factors predicted maladaptive outcomes in sexually abused children. Key factors were aggregated into four categories: abuse characteristics risk factors, individual-level risk factors, family disruption risk factors, and social disruption risk factors. It was hypothesized that (a) individual-level risk factors (e.g., school performance, child alcohol/substance abuse) and (b) abuse characteristics risk factors (e.g., longer duration/frequency of abuse, use of force/threats of force, intrafamilial abuse) would predict higher levels of trauma symptoms. Furthermore, it was hypothesized that (a) family disruption risk factors (e.g., family alcohol/substance use, family psychopathology) and (b) social disruption risk factors (e.g., parental divorce, homelessness, witnessing homicide or violence) would moderate the impact of prior sexual abuse and predict higher levels of trauma symptoms. ^ The participants were 110 female children (5 to 18 years old) presenting for treatment for sexual abuse at a community agency (The Journey Institute) in Miami, Florida. This study conducted a retrospective analysis of an archival data set collected over a three-year period (1998–2001). The measures completed upon intake included The Journey Psychosocial Assessment and The Trauma Symptom Checklist for Children (TSCC; Briere, 1996). Using Pearson correlations and hierarchical multiple regression analysis, this study found that abuse characteristics risk factors and individual-level risk factors were predictive of maladaptive outcomes in this sample of sexually abused girls. However, no moderating effects were found for family disruption risk factors or social disruption risk factors. Therefore, the results of these analyses provided support for the contention that abuse characteristics and individual-level risk factors were appropriate targets for treatment for sexually abused girls. Moreover, limitations of this study, implications for treatment, and directions for future research were discussed. ^

Teacher efficacy of special education teachers of English language learners with disabilities

This research examined the perceived teacher efficacy of special education teachers of English Language Learners (ELLs) with educational disabilities by surveying 202 elementary special education teachers using the EXCEL Teacher Inventory. EXCEL consists of 20 teacher efficacy items, three open-ended questions, and participant demographic items. ^ Overall participant teacher efficacy scores were high. Of the variables assessed, a statistically significant difference in perceived efficacy was found with self-reported proficiency in the language of the target students. No statistically significant differences in teacher efficacy scores were found for (a) levels of teacher preparation; (b) number of years of teaching experience; or (c) socioeconomic status of the students. A multiple regression analysis indicated that, of the variables listed above, proficiency in the language of the target students accounted for significant variance in predicting the level of teachers' perceived efficacy. ^ Responses to the open-ended questions about what was most helpful when working with ELLs with disabilities yielded two major themes: organizational issues and teacher issues. Participants wrote numerous comments about the value of support from educational professionals and parents. Many participants recommended individuals in preservice programs take ESOL content specific courses. ^ The results demonstrate the positive correlation between proficiency in the language of the target students and teacher efficacy. This suggests that teachers of ELLs with disabilities have proficiency in the ELLs' native language (or have support from others who are language proficient) that allows them to distinguish between language difference and language disability and provide instruction in the native language when needed. Further, results from open-ended questions suggest that special education teacher preparation programs should include courses related specifically to strategies for teaching ELLs with disabilities, not just ELLs. ^

Predictors of safer sex behaviors of midlife and older women

Heterosexual transmission of the human immunodeficiency virus (HIV) in midlife and older women is increasing, yet little is known about the safer sex practices of these women. Identification of HIV risk and protective factors necessitates understanding of the influences of individual, interpersonal, and socio-environmental factors on the sexual behaviors of this understudied, at-risk population. The purpose of this study was to determine the influence of self esteem, sensation seeking, self silencing, sexual assertiveness, and HIV-stigma on the safer sex behaviors of women aged 50 and older. ^ This study was guided by the ecological perspective which emphasizes the multilevel factors affecting health behaviors within individual, interpersonal, and socio-environmental contexts. A community-based, ethnically diverse sample of 572 women aged 50 to 93 (M = 63.6 years, SD = 10.5) completed a 128-item anonymous questionnaire. This study used a cross-sectional, correlational research design. The data were analyzed using Pearson correlation coefficients and multiple regression analysis. ^ Results from the regression analysis with the predictors (i.e., ethnicity, education, self esteem, sensation seeking, self silencing, sexual assertiveness, and HIV stigma) indicated the model significantly predicted safer sex behaviors (p < .001). Self silencing (β = -.115, p < .05) was a significant predictor. The lower the self silencing scores, the higher the safer sex behavior scores. Further exploration of the data revealed that the greater the age of the woman, the more likely she is to engage in safer sex behaviors (β = .173, p < .001). While the data showed this model was statistically significant, its practical significance may be limited due to the low proportion of variance explained by age and self silencing. HIV/AIDS prevention interventions that are socially anchored, age-appropriate, and gender-specific are discussed and recommendations for socially meaningful strategies to reduce the number of new cases of HIV/AIDS in midlife and older women are presented. ^

Development and validation of an instrument to predict online student success using faculty perceptions

Distance learning is growing and transforming educational institutions. The increasing use of distance learning by higher education institutions and particularly community colleges coupled with the higher level of student attrition in online courses than in traditional classrooms suggests that increased attention should be paid to factors that affect online student course completion. The purpose of the study was to develop and validate an instrument to predict community college online student course completion based on faculty perceptions, yielding a prediction model of online course completion rates. Social Presence and Media Richness theories were used to develop a theoretically-driven measure of online course completion. This research study involved surveying 311 community college faculty who taught at least one online course in the past 2 years. Email addresses of participating faculty were provided by two south Florida community colleges. Each participant was contacted through email, and a link to an Internet survey was given. The survey response rate was 63% (192 out of 303 available questionnaires). Data were analyzed through factor analysis, alpha reliability, and multiple regression. The exploratory factor analysis using principal component analysis with varimax rotation yielded a four-factor solution that accounted for 48.8% of the variance. Consistent with Social Presence theory, the factors with their percent of variance in parentheses were: immediacy (21.2%), technological immediacy (11.0%), online communication and interactivity (10.3%), and intimacy (6.3%). Internal consistency of the four factors was calculated using Cronbach's alpha (1951) with reliability coefficients ranging between .680 and .828. Multiple regression analysis yielded a model that significantly predicted 11% of the variance of the dependent variable, the percentage of student who completed the online course. As indicated in the literature (Johnson & Keil, 2002; Newberry, 2002), Media Richness theory appears to be closely related to Social Presence theory. However, elements from this theory did not emerge in the factor analysis.

Relations between acculturation and alcohol use among international students

In the current study, 226 international students attending Florida International University responded to an Web-based questionnaire that assessed self-reported scores for: acculturation, acculturative stress, alcohol use patterns, perceived peer alcohol use, and perceived injunctive social norms for alcohol use. The purpose of the study was to evaluate structural relations among this set of variables using Structural Equation Modeling (SEM) via AMOS 17.0. The results of SEM analyses documented acceptable fit of a model which hypothesized that relations between acculturation and alcohol use variables are mediated partially by acculturative stress, perceived peer alcohol use, and perceived injunctive social norms. While significant path coefficients were documented for paths between (a) acculturation and acculturative stress and (b) acculturative stress and alcohol use, the coefficients had negative signs, contrary to existing studies investigating these relations among immigrant youth. While paths between (a) perceived peer alcohol use or (b) perceived injunctive social norms and participants’ alcohol use were significant, path coefficients between acculturation and either (a) perceived peer alcohol use or (b) perceived injunctive social norms were not statistically significant. In addition, multiple-group comparisons suggested that social support had a significant moderating influence on several significant paths in the structural model. Specifically, international students reporting higher social support reported lower scores for acculturative stress and alcohol use, in contrast to their counterparts who reported lower scores for social support.

Evaluation of the internal structural validity of the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) anxiety disorders in children and adolescents

The purpose of the present dissertation was to evaluate the internal validity of symptoms of four common anxiety disorders included in the Diagnostic and Statistical Manual of Mental Disorders fourth edition (text revision) (DSM-IV-TR; American Psychiatric Association, 2000), namely, separation anxiety disorder (SAD), social phobia (SOP), specific phobia (SP), and generalized anxiety disorder (GAD), in a sample of 625 youth (ages 6 to 17 years) referred to an anxiety disorders clinic and 479 parents. Confirmatory factor analyses (CFAs) were conducted on the dichotomous items of the SAD, SOP, SP, and GAD sections of the youth and parent versions of the Anxiety Disorders Interview Schedule for DSM-IV (ADIS-IV: C/P; Silverman & Albano, 1996) to test and compare a number of factor models including a factor model based on the DSM. Contrary to predictions, findings from CFAs showed that a correlated model with five factors of SAD, SOP, SP, GAD worry, and GAD somatic distress, provided the best fit of the youth data as well as the parent data. Multiple group CFAs supported the metric invariance of the correlated five factor model across boys and girls. Thus, the present study’s finding supports the internal validity of DSM-IV SAD, SOP, and SP, but raises doubt regarding the internal validity of GAD.^