Use of a hyperbolic grid generation scheme in simulating supersonic viscous flow about three-dimensional winged configuration

The present paper describes a numerical mesh generation technique to be used with an implicit finite difference method for simulating visous supersonic flow about low-aspect-ratio wing body configurations using a single grid strategy. The computational domain is segmented into multiple regions, with borders located in supersonic areas to avoid the otherwise costly interfacing procedure between adjacent segments. The numerical procedure is applied to calculate the turbulent flow around the shuttle orbiter and a canard projectile at supersonic free stream Mach number

Viscous computation of a space shuttle flow field

A procedure is presented, as well as some results, to calculate the flow over the winged orbiter. This necessitates the use of two computer codes. A parabolized marching Navier-Stokes code is used to obtain the solution up to the bow shock-wing shock interaction region and for the region after the interaction. An unsteady Navier-Stokes code is to be used in the region of the shock interaction. Only resuls for the marching code are presented. For the flow conditions calculated, M infinity = 7.9, alpha = 25 deg, T(wall) = 540 R, Re(L) = 60728 per inch, laminar or turbulent, the PNS code was marched up to an X/L = 0.7 which is where the bow shock-wing shock interaction region occurs

Foreign body inhalation in the pediatric population: Lessons learned from 106 cases

SummaryObjectivesTo review the cases encountered in a tertiary care center so as to assess the incidence of foreign body aspiration in the pediatric population and to draw on our experience to improve prevention and early diagnosis.Patients and methodsRetrospective study of 106 children under the age of 15years, admitted to the Hôtel-Dieu de France hospital for flexible and/or rigid bronchoscopy between November 1998 and January 2010, for suspected foreign body aspiration (FBA).ResultsAmong the children, 56.6% were aged between one and three years. Peanuts or pistachios were found in 48% of cases. In 73% of cases, the FB was bronchial, and slightly more frequently on the right side (60%); 17.8% of cases presented in emergency immediately after inhalation; 12% presented with life-threatening symptoms; 29% presented within 24hours and 49% were seen later than 72hours. In 81% of subjects, a typical penetration syndrome was found on interviewing the parents. Physical pulmonary examination was normal in 21% of patients and chest X-ray in 21.8%. Rigid bronchoscopy was preceded by flexible bronchoscopy in 12% of cases. Parental underestimation of the gravity of the situation was a significant factor in delayed diagnosis. Among the patients, 64% examined 24hours after inhalation were initially treated for another pathology. Delay in diagnosis and organic vs inorganic FB did not significantly correlate with duration of bronchoscopy. The rate of complications did not significantly increase after a 24-hour diagnostic delay threshold.ConclusionFB aspiration is a serious problem. A high index of suspicion is required in health care providers (ENT, pediatricians and family physicians). Physician and especially parental education are the main guarantors of significantly reduced morbidity and mortality in this pathology

Dissociative multi-photon ionization of isolated uracil and uracil-adenine complexes

Recent multi-photon ionization (MPI) experiments on uracil revealed a fragment ion at m/z 84 that was proposed as a potential marker for ring opening in the electronically excited neutral molecule. The present MPI measurements on deuterated uracil identify the fragment as C3H4N2O+ (uracil+ less CO), a plausible dissociative ionization product from the theoretically predicted open-ring isomer. Equivalent measurements on thymine do not reveal an analogous CO loss channel, suggesting greater stability of the excited DNA base. MPI and electron impact ionization experiments have been carried out on uracil-adenine clusters in order to better understand the radiation response of uracil within RNA. Evidence for C3H4N2O+ production from multi-photon-ionized uracil-adenine clusters is tentatively attributed to a significant population of π-stacked configurations in the neutral beam

Impact of main idiosyncratic and exogenous factors on cost Efficiency: The case of MENA banking industries – SFA approach

У цьому дослідженні досліджується вплив основних ідіосинкратичних ендогенних (коефіцієнт капіталу, диверсифікація, ліквідність, рентабельність капіталу (ROE), розмір банківських активів) та макроекономічних екзогенних (рівень інфляції, темп зростання ВВП та індекс концентрації HHI) детермінантів банківської фірми, яка впливати на ефективність витрат банків. Використовуючи підхід SFA (Stochastic Frontier Approach), ми оцінюємо економічну ефективність банківських секторів Близького Сходу та Близького Сходу за допомогою двоетапної моделі: i) включаючи ідіосинкратичні та макроекономічні фактори на першому етапі за SFAW (SFA With) та ii) виключаючи ці фактори за SFAWO ( SFA без) на другому етапі. Використовуючи цей метод, SFAW проти SFAWO, ми порівнюємо межі ефективності та отримані бали та розуміємо вплив інтеграції основних детермінант на ефективність банків у регіоні MENA. Використовуючи вибірку з 240 спостережень для банків MENA, зібраних у 18 банківських секторах, ми аналізуємо, чи впливали ці критерії на ефективність витрат протягом 1999-2017 років. Ми виявили, що показники ефективності SFAW вищі, ніж SFAWO. Крім того, наші результати чітко показують вплив обраних детермінант на межу ефективності витрат. Нарешті, незважаючи на поточні фундаментальні зміни в банківській галузі Близького Сходу і Близького Сходу, емпіричні результати показують, що цю неефективність можна пояснити ідіосинкразичними факторами (розмір активів, ліквідність, прибутковість тощо), які знаходяться під контролем менеджерів банку та макроекономічного середовища. (економічне зростання, інфляція), що значною мірою залежить від економічної, монетарної та фінансової політики, прийнятої в кожній країні регіону MENA.This study explores the impact of main idiosyncratic endogenous (Capital ratio, Diversification, Liquidity, Return on equity (ROE), Banks assets’ size) and macroeconomic exogenous (Inflation rate, GDP growth rate and HHI concentration index) determinants of the banking firm that influence banks’ cost efficiency. Using the SFA (Stochastic Frontier Approach) we estimate cost efficiency of the MENA banking sectors through a two-stage model: i) Including idiosyncratic and macroeconomic factors at a first stage under SFAW (SFA With) and ii) excluding these factors under SFAWO (SFA without) at a second stage. By using this method, SFAW versus SFAWO, we compare between the efficiency frontiers and scores obtained and understand the effect of the integration of main determinants on efficiency of banks in the MENA region. Using a sample of 240 observations for MENA banks collected from 18 banking sectors, we analyze whether these criteria had impact on cost efficiency throughout 1999-2017. We find that SFAW scores of efficiency are higher than SFAWO. Furthermore, our results show clearly the impact of determinants selected on cost efficiency frontier. Finally, notwithstanding ongoing fundamental changes in MENA’s banking industries, the empirical results, show that these inefficiencies can be explained by the idiosyncratic factors (Assets ‘size, liquidity, profitability, etc.) which are under the control of bank managers and the macroeconomic environment (economic growth, inflation) which largely depends on the economic, monetary and financial policies adopted in each country of the MENA region

Role assigning and taking in cloud computing

The widespread use of cloud computing (CC) has brought to the forefront information technology (IT) governance issues, rendering the lack of expertise in handling CC-based IT controls a major challenge for business enterprises and other societal organizations. In the cloud-computing context, this study identifies and ranks the determinants of role assigning and taking by IT people. The study’s integrative research links CC and IT governance to humane arrangements, as it validates and ranks role assigning and taking components through in-depth interviews with twelve IT decision-makers and forty-four Information Systems Audit and Control Association (ISACA) members, engaged as panelists in a Delphi technique implementation. The empirical results recognize skills and competencies as prioritized determinants of IT controls, while IT security, risk and compliance emerge as capabilities crucial to evaluate and manage CC service providers. Despite the study’s generalizability limitations, its findings highlight future research paths and provide practical guidelines toward the high technology of open-market IT self-governance. The latter entails the humane flows of collegial control and responsibility, as opposed to the inhumane flows of authority and power, under the sequestered technique of the bureaucratically-hierarchized IT hetero-governanc

Sunlight exposure is just one of the factors which influence Vitamin D status

© The Royal Society of Chemistry and Owner Societies. Studies on the determinants of vitamin D status have tended to concentrate on input-exposure to ultraviolet B radiation and the limited sources in food. Yet, vitamin D status, determined by circulating concentrations of 25-hydroxyvitamin D (25(OH)D), can vary quite markedly in groups of people with apparently similar inputs of vitamin D. There are small effects of polymorphisms in the genes for key proteins involved in vitamin D production and metabolism, including 7-dehydrocholesterol reductase, which converts 7-dehydrocholesterol, the precursor of vitamin D, to cholesterol, CYP2R1, the main 25-hydroxylase of vitamin D, GC, coding for the vitamin D binding protein which transports 25(OH)D and other metabolites in blood and CYP24A1, which 24-hydroxylates both 25(OH)D and the hormone, 1,25-dihydroxyvitamin D. 25(OH)D has a highly variable half-life in blood. There is evidence that the half-life of 25(OH)D is affected by calcium intake and some therapeutic agents. Fat tissue seems to serve as a sink for the parent vitamin D, which is released mainly when there are reductions in adiposity. Some evidence is presented to support the proposal that skeletal muscle provides a substantial site of sequestration of 25(OH)D, protecting this metabolite from degradation by the liver, which may help to explain why exercise, not just outdoors, is usually associated with better vitamin D status