Stochastic representation of the Reynolds transport theorem: revisiting large-scale modeling

We explore the potential of a formulation of the Navier-Stokes equations incorporating a random description of the small-scale velocity component. This model, established from a version of the Reynolds transport theorem adapted to a stochastic representation of the flow, gives rise to a large-scale description of the flow dynamics in which emerges an anisotropic subgrid tensor, reminiscent to the Reynolds stress tensor, together with a drift correction due to an inhomogeneous turbulence. The corresponding subgrid model, which depends on the small scales velocity variance, generalizes the Boussinesq eddy viscosity assumption. However, it is not anymore obtained from an analogy with molecular dissipation but ensues rigorously from the random modeling of the flow. This principle allows us to propose several subgrid models defined directly on the resolved flow component. We assess and compare numerically those models on a standard Green-Taylor vortex flow at Reynolds 1600. The numerical simulations, carried out with an accurate divergence-free scheme, outperform classical large-eddies formulations and provides a simple demonstration of the pertinence of the proposed large-scale modeling

Corneal Dermoid

A 20 years old boy presented with left corneal mass. The mass involved entire cornea extending to the sclera. The mass had a skin like surface and protruded outside the palpebral aperture. The eye with the mass was excised .The histopathology report confirmed the diagnosis of corneal dermoid. This late presentation of huge corneal dermoid extending to sclera is first such report in the literature

Over the counter ophthalmic drug misuse, are we aware?

Aim: To investigate the misuse of ‘over the counter’ ophthalmic medications in our city. Method: Responses of a structured questionnaire covering various aspects of over the counter drug use was obtained from pharmacy workers in and around our city. Results: Eighty nine pharmacy workers took part in this cross–sectional study. An average number of seven patients per day with ophthalmic complaints were seen by the pharmacy workers. Dispensing over the counter was practiced by 89.9% of the pharmacists. The most common complaint of the patients visiting the pharmacy, was redness and itching (86.5%). Antibiotics (96.6%) were the most common eye drops dispensed over the counter, followed by steroids (55.1%), decongestants (54.1%), antibiotic-steroid combination eye drops (29.2%) and lubricants (16.8%). Awareness regarding complications of steroid use was seen in 40.6% of pharmacists. 6.7% pharmacists had seen patients with complications following use of over the counter medications. In our study, majority of the eye drops dispensed were prescription drugs. Conclusion: Availability of prescription eye drops over the counter is an immense public threat. Educating the pharmacist and the population can decrease ocular morbidity. Research into methods to effectively deal with over-the-counter drug misuse is required and law can be enforced based on the findings

An overview of hospital acquired infections and the role of the microbiology laboratory

Every year, many lives are lost because of the spread of infections in hospitals. These nosocomial infections, also called hospital acquired infections (HAI) are infections that patients acquire during the course of receiving healthcare treatment for other conditions. HAIs are a cause of significant morbidity and mortality in patients receiving healthcare, and the costs direct and indirect of these infections deplete the already limited financial resources allocated to healthcare delivery

Aerobic bacteriology of chronic suppurative otitis media: a hospital based study

Background: Chronic suppurative otitis media (CSOM) remains one of the most common childhood chronic infectious diseases worldwide, affecting diverse racial and cultural groups both in developing and industrialized countries. It involves considerable morbidity and can cause extra- and intra-cranial complications. The aim of this study was to determine the microbial diversity and the antibiogram of aerobic bacterial isolates among patients suffering from CSOM who attended the ENT Department of SMHS hospital, a tertiary care centre located in the heart of the Kashmir valley.Methods: A total of 154 patients clinically diagnosed with CSOM were enrolled in the study and the samples were obtained from each patient using sterile cotton swabs and cultured for microbial flora. Drug susceptibility testing for aerobic isolates was conducted using Kirby-Bauer disc diffusion method.Results: Out of total 154 ear swabs processed, microbial growth was seen in 138 (89.61%) while 16 (10.38%) samples showed no growth. In 102 (66.23%) samples mono-microbial growth was seen whereas 26 (16.88%) samples showed poly-microbial growth. The most frequent organism isolated was Pseudomonas aeroginsa followed by Staphylococcus aureus and Proteus sp. The most effective antibiotic against Pseudomonas aeroginsa was amikacin followed by imipenem and piperacillin plus tazobactam, while as Staphylococcus aureus showed maximum sensitivity to vancomycin.Conclusion: Otitis media linked with high levels of multiple antibiotic resistant bacteria is a major health concern in all age groups of the study population. An appropriate knowledge of the etiology and antibacterial susceptibility of microorganisms would contribute to a rational antibiotic use and the success of treatment for chronic supportive otitis media.

Efficient method for transformer models implementation in distribution load flow matrix

Introduction. Most distribution networks are unbalanced and therefore require a specific solution for load flow. There are many works on the subject in the literature, but they mainly focus on simple network configurations. Among the methods dedicated to this problem, one can refer to the load flow method based on the bus injection to branch current and branch current to bus voltage matrices. Problem. Although this method is regarded as simple and complete, its drawback is the difficulty in supporting the transformer model as well as its winding connection types. Nevertheless, the method requires the system per unit to derive the load flow solution. Goal. In the present paper, our concern is the implementation of distribution transformers in the modeling and calculation of load flow in unbalanced networks. Methodology. Unlike previous method, distribution transformer model is introduced in the topology matrices without simplifying assumptions. Particularly, topology matrices were modified to take into account all winding types of both primary and secondary sides of transformer that conserve the equivalent scheme of an ideal transformer in series with an impedance. In addition, the adopted transformer models overcome the singularity problem that can be encountered when switching from the primary to the secondary side of transformer and inversely. Practical value. The proposed approach was applied to various distribution networks such as IEEE 4-nodes, IEEE 13-nodes and IEEE 37-nodes. The obtained results validate the method and show its effectiveness.Вступ. Більшість розподільчих мереж незбалансовані і тому потребують спеціального рішення для потоку навантаження. У літературі є багато робіт на цю тему, але переважно вони присвячені простим мережевим конфігураціям. Серед методів, присвячених цій проблемі, можна назвати метод потоку навантаження, заснований на введенні шини в матрицю струму відгалуження і відгалуження струму в матрицю напруги шини. Проблема. Хоча цей метод вважається простим та повним, його недоліком є складність підтримки моделі трансформатора, а також типів з’єднання його обмоток. Проте метод вимагає системи на одиницю для отримання рішення про потік навантаження. Мета. У цій статті нас цікавить застосування розподільних трансформаторів для моделювання та розрахунку потоку навантаження у незбалансованих мережах. Методологія. На відміну від попереднього методу, модель розподільного трансформатора вводиться в матриці топології без спрощення припущень. Зокрема, матриці топології були змінені, щоб врахувати всі типи обмоток як первинної, так і вторинної сторін трансформатора, які зберігають еквівалентну схему послідовно ідеально включеного трансформатора з імпедансом. Крім того, прийняті моделі трансформаторів долають проблему сингулярності, з якою можна зіткнутися при перемиканні з первинної на вторинну обмотку трансформатора і навпаки. Практична цінність. Пропонований підхід був застосований до різних розподільних мереж, таких як IEEE з 4 вузлами, IEEE з 13 вузлами та IEEE з 37 вузлами. Отримані результати підтверджують метод та показують його ефективність