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

Utility-driven Optimization of TTL Cache Hierarchies under Network Delays

We optimize hierarchies of Time-to-Live (TTL) caches under random network delays. A TTL cache assigns individual eviction timers to cached objects that are usually refreshed upon a hit where upon a miss the object requires a random time to be fetched from a parent cache. Due to their object decoupling property, TTL caches are of particular interest since the optimization of a per-object utility enables service differentiation. However, state-of-the-art exact TTL cache optimization does not extend beyond single TTL caches, especially under network delays. In this paper, we leverage the object decoupling effect to formulate the non-linear utility maximization problem for TTL cache hierarchies in terms of the exact object hit probability under random network delays. We iteratively solve the utility maximization problem to find the optimal per-object TTLs. Further, we show that the exact model suffers from tractability issues for large hierarchies and propose a machine learning approach to estimate the optimal TTL values for large systems. Finally, we provide numerical and data center trace-based evaluations for both methods showing the significant offloading improvement due to TTL optimization considering the network delays

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

Effect of stage-based education provided by dedicated dietitians on hyperphosphataemic haemodialysis patients: results from the Nutrition Education for Management of Osteodystrophy randomised controlled trial

© 2017 The British Dietetic Association Ltd. Background: The Nutrition Education for Management of Osteodystrophy trial showed that stage-based nutrition education by dedicated dietitians surpasses existing practices in Lebanon with respect to lowering serum phosphorus among general haemodialysis patients. The present study explores the effect of nutrition education specifically on hyperphosphataemic patients from this trial. Methods: Hyperphosphataemic haemodialysis patients were allocated to a dedicated dietitian (DD), a trained hospital dietitian (THD) and existing practice (EP) protocols. From time-point (t)-0 until t-1 (6 months), the DD group (n = 47) received 15 min of biweekly nutrition education by dedicated dietitians trained on renal nutrition; the THD group (n = 89) received the usual care from trained hospital dietitians; and the EP group (n = 42) received the usual care from untrained hospital dietitians. Patients were followed-up from t-1 until t-2 (6 months). Analyses used two-way repeated measures analysis of variance and Cohen\u27s effect sizes (d). Results: At t-1, phosphataemia significantly decreased in all groups (DD:−0.27 mmol L−1; EP:−0.15 mmol L−1; THD:−0.12 mmol L−1; P \u3c 0.05); the DD protocol had the greatest effect relative to EP (d = −0.35) and THD (d = −0.50). Only the DD group showed more readiness to adhere to a low phosphorus diet at t-1; although, at t-2, this regressed to baseline levels. The malnutrition inflammation score remained stable only in the DD group, whereas the EP and THD groups exhibited a significant increase (DD: 6.74, 6.97 and 7.91; EP: 5.82, 8.69 and 8.13; THD: 5.33, 7.92 and 9.42, at t-0, t-1 and t-2, respectively). Conclusions: The results of the present study suggest that the DD protocol decreases serum phosphorus compared to EP and THD, at the same time as maintaining the nutritional status of hyperphosphataemic haemodialysis patients. Assessing the cost-effectiveness of the DD protocol is recommended

U.V. spectra parameters to investigate the influences of intensifications of soybean with sorghum and maize on the physical properties of soybean seed oils

Using U.V. spectra measurements as a tool to investigate the influences of intensifications or intercroping of crops on the physical properties of the constituents of the yielded grains or seeds. In this paper the authors used U.V. spectra measurement to deduce the effects of intensifications of Clark and Crowmord soybean varieties on some sorghum and maize varieties on the physical properties of the oils of the soybean seed varieties. Results of this work revealed that the highest U.V. spectra measurements at bands 270 nm, were 2.5 for the oils of Crowmord soybean seed variety intensificated on Giza 15 sorghum variety intensity 2:4 (2 rows soybean: 4 rows sorghum) and Giza 2, Hz 215 and Hz 310 maize varieties, intensity 2:2, 2:4, 2:4 and 2:2 respectively in the regions of spectra differences. The intensification of Clark and Crowmord soybean varieties on sorghum and maize is effective as the physical properties of their oils improved by increasing the cromophor and carotenoids compound levels.Se usaron medidas de espectros U.V. como una herramienta para investigar las influencias de intensificaciones o intercultivos sobre las propiedades físicas de los constituyentes de granos o semillas producidos. En este trabajo el autor usó medidas de espectros U.V. para deducir los efectos de intensificaciones de variedades de soja Clark y Crowmord con variedades de sorgo y maíz sobre las propiedades físicas de los aceites de soja. Los resultados de este trabajo revelaron que los valores de espectros U.V. más elevados a 270 nm, fueron 2'5 para los aceites de variedades de semilla de soja Crowmord intensificado con la variedad sorgo Giza 15 (2 filas soja: 4 filas sorgo) y las variedades de maíz Giza 2 (2:2 y 2:4), Hz 215 (2:4) y Hz 310 (2:2). La intensificación de variedades de soja Clark y Crowmord con sorgo y maíz es efectiva, ya que las propiedades físicas de sus aceites mejoraron por aumento de los niveles de compuestos cromóforos y carotenoides