Analysis, design, fabrication and testing of an optical tip clearance sensor

Analyses and the design, fabrication, and testing of an optical tip clearance sensor with intended application in aircraft propulsion control systems are reported. The design of a sensor test rig, evaluation of optical sensor components at elevated temperatures, sensor design principles, sensor test results at room temperature, and estimations of sensor accuracy at temperatures of an aircraft engine environment are discussed. Room temperature testing indicated possible measurement accuracies of less than 12.7 microns (0.5 mils). Ways to improve performance at engine operating temperatures are recommended. The potential of this tip clearance sensor is assessed

Social Media: A Security Threat amongst Adolescents in Buea, Cameroon?

Social media provide a platform through which societies can either be constructed or destabilized. In view of the ongoing bloody conflicts in Cameroon, this study examines the extent to which social media could pose as a security threat (with particular focus on community security) amongst adolescents in Buea, capital of the South West Region in Cameroon. The study uses a quantitative approach, through the collection of data from adolescents in four communities in Buea (Muea, Bomaka, Mile 16, and Molyko). These four areas are selected because the current socio-political crisis rocking the two Anglophone regions of the country – Northwest and Southwest, is particularly severe in these communities. Social media (notably Facebook and WhatsApp) spread dangerous content, and adolescents are vulnerable to such content. Findings indicate that there is a high rate of social media use (Facebook and WhatsApp) amongst adolescents surveyed. Also, the most discussed items on social media are socio-cultural issues (68%), as opposed to political issues (17.8%). Respondents were receptive to discussions on socio-cultural issues like dressing, language and relationships. Results also show that though adolescents come across violent content on social media, they have distanced themselves from being involved in the production, consumption, and dissemination (for instance, share information as received) of such violent content, partly because of the judicial consequences of doing so, as contained in the country’s Terrorism Law of December 2014. The implication here is that, since the adolescents are not yet intoxicated (whether advertently or inadvertently) with destructive social media content, need exists for the effective education of the adolescents, to enable this vulnerable and younger population to continue desisting from negative social media content. Emphasis should be on the consumption of positive social media content that helps in the moral and psychological growth of adolescents

Perceptions Of School By Two Teenage Boys With Asperger Syndrome And Their Mothers: A Qualitative Study

This qualitative study aimed to develop an understanding of the challenges faced by teenage boys with Asperger syndrome and their mothers. A case study approach was used to collect data from two 13-year-old boys who have Asperger syndrome and their mothers in Queensland, Australia. Data were collected through the use of semi¬structured interviews. The words of the boys and their mothers provide a valuable insight into the personal experiences and feelings of the par¬ticipants. An inductive approach to data analysis identified four themes: (1) developmental differences; (2) problems associated with the general characteristics of Asperger syndrome (i.e. communication and social difficulties, restricted range of interests, a need for routine); (3) stress; and (4) 'masquerading'. The first three themes relate strongly to the current literature, but the emergence of masquerading is of particular interest in developing a fuller understanding of the experiences of individuals with Asperger syndrome at school

Sex Hormone-Binding Globulin Levels Are Inversely Associated With Nonalcoholic Fatty Liver Disease in HIV-Infected and -Uninfected Men.

BackgroundNonalcoholic fatty liver disease (NAFLD) is a leading cause of liver disease worldwide. Elevated sex hormone-binding globulin (SHBG) levels have been observed in the setting of HIV and may protect against some metabolic disorders. We aimed to investigate whether higher SHBG levels may protect against NAFLD in men with/without HIV.MethodsNAFLD was assessed using noncontrast computed tomography in 530 men in the Multicenter AIDS Cohort Study (MACS) who drank <3 alcoholic drinks/d and were uninfected with chronic hepatitis C or B (340HIV+, 190HIV-). Morning serum samples were tested for SHBG, total testosterone (TT), and adiponectin. Multivariable logistic regression was used to assess associations between HIV, SHBG, TT, adiponectin, and NAFLD.ResultsMedian SHBG was highest among HIV+/NAFLD- men and lowest among HIV-/NAFLD+ men. Adjusted for demographics, HIV, visceral adiposity, HOMA-IR, TT, and PNPLA3 genotype, higher SHBG was associated with lower odds of NAFLD (odds ratio [OR], 0.52 per doubling; 95% confidence interval [CI], 0.34-0.80). In separate multivariable models without SHBG, HIV (OR, 0.46; 95% CI, 0.26-0.79) and higher adiponectin (OR, 0.66 per doubling; 95% CI, 0.49-0.89) were associated with lower NAFLD odds, whereas TT was not significantly associated (OR, 0.74 per doubling; 95% CI, 0.53-1.04). Adjusting for SHBG attenuated the associations of HIV (OR, 0.61; 95% CI, 0.34-1.08) and adiponectin (OR, 0.74; 95% CI, 0.54-1.02) with NAFLD.ConclusionsSHBG levels were higher among HIV+ men, were independently associated with lower NAFLD, and could partially explain the associations of HIV and higher adiponectin with lower NAFLD in our cohort. These findings suggest that SHBG may protect against NAFLD, supporting further prospective and mechanistic studies

Maternal residential proximity to major roadways, birth weight, and placental DNA methylation

Exposure to traffic pollution during fetal development has been associated with reduced fetal growth, and there is evidence to suggest that epigenetic mechanisms in the placenta in the form of variant DNA methylation may be a potential mechanism of this effect

Going beyond children’s single-text comprehension:The role of fundamental and higher–level skills in 4th graders’ multiple-document comprehension

Background: Children's comprehension of single texts relies on both foundational and higher-level skills. These are also assumed to support multiple-document comprehension, but their relative importance has not been examined, to date. Multiple-document comprehension additionally requires the identification and use of information about each document's source. Aims: This study examined multiple-document comprehension in primary school-aged children. It sought to determine the relative importance of skills proposed to be common to both single-text and multiple-document comprehension (word reading fluency, verbal working memory, comprehension monitoring) and specific to the latter (source use). Single-text comprehension and prior topic knowledge were considered as moderator and control. Sample: Participants were 94 children in the fourth year (mean age = 9; 7 years; 52% females). Methods: Children read three documents on each of two topics (chocolate and video games). Multiple-document comprehension and source use were assessed through short essays. Independent measures of the fundamental and higher-level skills were used. Results: There was a significant direct and indirect influence of word reading fluency on comprehension of multiple documents on videogames and also an indirect influence of comprehension monitoring. Indirect influences of word reading fluency and comprehension monitoring on multiple-document comprehension for both topics were also apparent. Verbal working memory was not a unique predictor. When source information was identified, it was included to support the argument in the composition. Conclusions: Efficient word reading, comprehension monitoring, and single-text comprehension are important for multiple-document comprehension in young readers. Implications of these findings and differences between the two document sets are discussed

APOE Genotype Modulates Proton Magnetic Resonance Spectroscopy Metabolites in the Aging Brain

Background: Proton magnetic resonance spectroscopy (H-1-MRS) studies on healthy aging have reported inconsistent findings and have not systematically taken into account the possible modulatory effect of APOE genotype. We aimed to quantify brain metabolite changes in healthy subjects in relation to age and the presence of the APOE E4 genetic risk factor for Alzheimer\u27s disease. Additionally, we examined these measures in relation to cognition. Methods: We studied a cohort of 112 normal adults between 50 and 86 years old who were genotyped for APOE genetic polymorphism. Measurements of H-1-MRS metabolites were obtained in the posterior cingulate and precuneus region. Measures of general cognitive functioning, memory, executive function, semantic fluency, and speed of processing were also obtained. Results: General linear model analysis demonstrated that older APOE E4 carriers had significantly higher choline/creatine and myoinositol/creatine ratios than APOE E3 homozygotes. Structural equation modeling resulted in a model with an excellent goodness of fit and in which the APOE x age interaction and APOE status each had a significant effect on H-1-MRS metabolites (choline/creatine and myo-inositol/creatine). Furthermore, the APOE x age variable modulation of cognition was mediated by H-1-MRS metabolites. Conclusions: In a healthy aging normal population, choline/creatine and myo-inositol/creatine ratios were significantly increased in APOE E4 carriers, suggesting the presence of neuroinflammatory processes and greater membrane turnover in older carriers. Structural equation modeling analysis confirmed these possible neurodegenerative markers and also indicated the mediator role of these metabolites on cognitive performance among older APOE E4 carriers