Experimental measurements of the laminar separation bubble on an Eppler 387 airfoil at low Reynolds numbers

An experimental investigation was conducted to measure the flow velocity in the boundary layer of an Eppler 387 airfoil. In particular, the laminar separation bubble that this airfoil exhibits at low Reynolds numbers was the focus. Single component laser Doppler velocimetry data were obtained at a Reynolds number of 100,000 at an angle of attack of 2.0 degree. Static Pressure and flow visualization data for the Eppler 387 airfoil were also obtained. The difficulty in obtaining accurate experimental measurements at low Reynolds numbers is addressed. Laser Doppler velocimetry boundary layer data for the NACA 663-018 airfoil at a Reynolds number of 160,000 and angle of attack of 12 degree is also presented

The Influence of Manual and Hydraulic Stretchers on Recruitment, Retention, and Turnover in the Emergency Medical Services Workforce

The Department of Labor predicts an increase in demand for Emergency Medical Services (EMS) as the United States’ population grows older. The leaders of EMS must confront the difficulties surrounding recruitment, retention, and employment turnover of the EMS workforce to ensure a solvent employment pipeline to meet the predicted service demands. Previous researchers found that hydraulic stretchers reduced the number of occupationally acquired injuries among the EMS workforce. Grounded in human capital development and corporate social responsibility theories, this study extended from the work of Brice et al. (2012), Fredericks, Butt, and Hovenkamp (2009), and Studnek, Crawford, & Fernandez, (2011) who found that hydraulic stretchers have a positive influence on job satisfaction, lost workdays, and absenteeism. This study examined the relationship between EMS employment turnover, retention, and recruitment and stretcher systems. This study used a causal comparative design, survey solicitation of data, and a multivariate analysis of covariance as the statistical methodology. The researcher concluded that stretcher type does not influence recruitment, retention, and turnover in this study group. This study improves the understanding of workforce outcomes as influenced by the type of stretcher systems used in EMS. Future EMS workforce research should focus on employment attractors and detractors to women in EMS and investigate the relationship among ambulance call volume, service type, EMS employment conditions, recruitment, retention, and turnover

Modular MRI Guided Device Development System: Development, Validation and Applications

Since the first robotic surgical intervention was performed in 1985 using a PUMA industrial manipulator, development in the field of surgical robotics has been relatively fast paced, despite the tremendous costs involved in developing new robotic interventional devices. This is due to the clear advantages to augmented a clinicians skill and dexterity with the precision and reliability of computer controlled motion. A natural extension of robotic surgical intervention is the integration of image guided interventions, which give the promise of reduced trauma, procedure time and inaccuracies. Despite magnetic resonance imaging (MRI) being one of the most effective imaging modalities for visualizing soft tissue structures within the body, MRI guided surgical robotics has been frustrated by the high magnetic field in the MRI image space and the extreme sensitivity to electromagnetic interference. The primary contributions of this dissertation relate to enabling the use of direct, live MR imaging to guide and assist interventional procedures. These are the two focus areas: creation both of an integrated MRI-guided development platform and of a stereotactic neural intervention system. The integrated series of modules of the development platform represent a significant advancement in the practice of creating MRI guided mechatronic devices, as well as an understanding of design requirements for creating actuated devices to operate within a diagnostic MRI. This knowledge was gained through a systematic approach to understanding, isolating, characterizing, and circumventing difficulties associated with developing MRI-guided interventional systems. These contributions have been validated on the levels of the individual modules, the total development system, and several deployed interventional devices. An overview of this work is presented with a summary of contributions and lessons learned along the way

Individual And Population Responses Of The Caribbean Sponge, Aplysina Cauliformis, To Natural And Anthropogenic Stressors

Coral reefs are under increasing threat from a diversity of stressors. These reefs have undergone a phase shift from coral-dominated to algal-dominated ecosystems, and in many cases other functional groups such as sponges are now the predominant organisms on many reefs. This dissertation investigated the responses of a combranching sponge, Aplysina cauliformis, to algal contact, eutrophication, hurricanes, and disease. The effects of algal competition, anthropogenic nutrients and a combination of these stressors on A. cauliformis were examined using factorial designed field experiments on Bahamian reefs. These experiments demonstrated a complex interaction between sponge and alga, in which the green alga, Microdictyon marinum, elicited a competitive effect on the sponge, through shading of its photosymbionts, but contact with the sponge facilitated increased algal productivity. Elevated nutrient concentrations had a positive effect on M. marinum by increasing algal productivity, but shomixed effects on A. cauliformis, by increasing sponge symbiont abundance, while decreasing overall holobiont health. A further investigation of the sponge-algal interaction using stable isotopes of carbon and nitrogen shothat algal facilitation was likely due to nitrogen transfer from the sponge. In addition, these experiments shothat algal contact did not have acute effects on internal sponge regulation and partitioning of carbon and nitrogen resources. The fate and dynamics of the sponge disease Aplysina Red Band Syndrome (ARBS) in A. cauliformis were investigated in situ. This study shothat ARBS infection decreased an individual\u27s chance of survival on the reef. Dynamics of ARBS were investigated using spatial pattern analysis of A. cauliformis populations and revealed that direct physical contact was the transmission mechanism for ARBS within a population. In the three year period of this study, hurricane effects on sponge population an disease dynamics were also investigated, and shoa dramatic loss in sponge population biomass, increased breakage, especially in diseased individuals, and randomization of ARBS distribution within the population. With current environmental conditions often favoring alternative states in which organisms such as sponges and/or algae are the dominant organisms, it is important to understand how these organisms respond to multiple environmental stressors

Reconstructing Civility after Wrongdoing: A Place for Restorative Justice

Demonstration of mediation techniques that offer an alternative to retributive justice responses to wrongdoing

Obesity and metabolic syndrome in adolescent survivors of standard risk childhood acute lymphoblastic leukemia in Saudi Arabia

This study estimated prevalence of unhealthy weight status and metabolic syndrome (MS) amongst Saudi survivors of standard risk ALL. Procedure. We recruited 56 survivors, mean age 13.4 years (SD 4.1), a mean of 9.1 years (SD 4.1) postdiagnosis. The BMI for age was used to define weight status relative to national (Saudi) and international (Cole et al., Cole-IOTF, WHO, and CDC) reference data. We measured body composition by dualenergy X-ray absorptiometry (DXA), waist circumference, blood pressure, lipid profile (HDL-C, Triglycerides), fasting glucose and insulin. Results. According to international definitions based on BMI for age, around half of the sample had unhealthy weight status. All of the approaches based on BMI for age underestimated overfatness, present in 27/51 (53%) of the sample according to DXA. Prevalence of MS was 7.1% (3/42 of those over 9-years old) and 5.4% (3/56) by applying the International Diabetes Federation (IDF) definition and National Cholesterol Education Program Third Adult Treatment panel Guidelines (NCEP III), respectively. However, MS by the NCEP III definition was present in 19% of the overweight and obese survivors and 7.1% of the sample had at least two of the components of MS. Conclusion. Unhealthy body weight and overfatness may be common amongst adolescent Saudi survivors of standard risk ALL, though overweight and obesity may be no more common than in the general Saudi adolescent population. Defining weight status using BMI underestimates overfatness. Ideally, body composition and cardiometabolic risk factors should be monitored at late effects clinics. Pediatr Blood Cancer 2012;59: 133–137. 2011 Wiley Periodicals, Inc

A New Spin on the Weak Gravity Conjecture

The mild form of the Weak Gravity Conjecture states that quantum or higher-derivative corrections should decrease the mass of large extremal charged black holes at fixed charge. This allows extremal black holes to decay, unless protected by a symmetry (such as supersymmetry). We reformulate this conjecture as an integrated condition on the effective stress tensor capturing the effect of quantum or higher-derivative corrections. In addition to charged black holes, we also consider rotating BTZ black holes and show that this condition is satisfied as a consequence of the $c$-theorem, proving a spinning version of the Weak Gravity Conjecture. We also apply our results to a five-dimensional boosted black string with higher-derivative corrections. The boosted black string has a $\text{BTZ}\times S^2$ near-horizon geometry and, after Kaluza-Klein reduction, describes a four-dimensional charged black hole. Combining the spinning and charged Weak Gravity Conjecture we obtain positivity bounds on the five-dimensional Wilson coefficients that are stronger than those obtained from charged black holes alone.Comment: 29 pages + appendices, 4 figure