New Approaches to Gortler and Tollmien-Schlichting Boundary-Layer Instabilities

A detailed understanding of the physical processes that lead to instability and transition in the external viscous boundary layers of airfoils has been the goal of researchers for decades. This study seeks to enhance our understanding of Gortler and Tollmien-Schlichting instabilities through a critical review of prior theoretical methodology and fundamental experiments, the development of dimensionally consistent disturbance equations, and novel interpretation of the resulting flow physics revealed by their solutions to explain the process of transition. Gortler vortices arise in boundary layers along concave surfaces due to centrifugal effects and these vortices in combination with other instabilities play an important role in triggering early transition. Of the two distinct theoretical approaches to Gortler instability, the marching technique initiated by Hall led to multiple neutral curves that depended on the initial condition and its location, and the classical normal-node approach where each study predicted a unique but different neutral curve. This study critically examines the two approaches, provides explanations for the differences, and shows that the two can produce compatible results for constant concave curvature. The first ever study of Gortler instability on variable curvature surfaces is presented. A hitherto unknown phenomenon of the Gortler vortices lifting off in the convex region is observed

Drug eluting stents versus bare metal stents in coronary artery disease patients: outcomes and complications

Background: To date, data regarding the long-term safety and efficacy of BMS and DES implantation in a real-world population are limited. Thus, this study was designed to study the complications, early and late outcomes of drug-eluting stents (DES) versus bare metal stents (BMS) after implantation in coronary artery disease (CAD) patients up to 6months follow-up period.Methods: This was a single-center, hospital-based, prospective study conducted at a tertiary care center in India. Records of 250 patients who underwent percutaneous coronary intervention (PCI) in the period of January to December 2007 were included in the study. Early outcomes were indications of coronary angioplasty, length of hospital stay, Killip’s classification at presentation, type of coronary lesions, cath-lab outcomes and acute stent thrombosis (ST). Patients were clinically followed-up till hospital discharge, 30days and in 6months.Results: Total 250 patients with an age range of 30-39years underwent PCI. Of the study population who underwent PCI 111 patients (44.4%) received DES, 104 patients (8%) received BMS, 20 patients received both DES and BMS and 15 patients underwent POBA, respectively. Complications like stroke and major bleeding were observed in 2 patients (0.8%) and 12 patients (4.8%) respectively. TIMI III flow and ST was observed in 215 patients (91.5%) and 6 patients (2.6%), respectively. Death was observed in 3 patients (1.2%) due to cardiogenic shock.Conclusions: DES and BMS have good procedural success in achieving early revascularization with PCI. The incidence of ST was almost equal in DES compared to BMS

American Airlines: Bankrupt, Like Every Other Legacy Airline

American held out to the end, being the last of the large legacy carriers to file for Chapter 11 protection. This case reviews the history of American from its inception through its filing. Current strategies and industry trends are also examined

Mind the Gap: The Difference Between Coverage and Mutation Score Can Guide Testing Efforts

An "adequate" test suite should effectively find all inconsistencies between a system's requirements/specifications and its implementation. Practitioners frequently use code coverage to approximate adequacy, while academics argue that mutation score may better approximate true (oracular) adequacy coverage. High code coverage is increasingly attainable even on large systems via automatic test generation, including fuzzing. In light of all of these options for measuring and improving testing effort, how should a QA engineer spend their time? We propose a new framework for reasoning about the extent, limits, and nature of a given testing effort based on an idea we call the oracle gap, or the difference between source code coverage and mutation score for a given software element. We conduct (1) a large-scale observational study of the oracle gap across popular Maven projects, (2) a study that varies testing and oracle quality across several of those projects and (3) a small-scale observational study of highly critical, well-tested code across comparable blockchain projects. We show that the oracle gap surfaces important information about the extent and quality of a test effort beyond either adequacy metric alone. In particular, it provides a way for practitioners to identify source files where it is likely a weak oracle tests important code

Dermatoglyphics: A Marker of Periodontal Disease

Dermatoglyphics is the scientific study of fingerprint patterns. Fingerprints are formed in early embryonic life, during the 10th to 16th weeks of intrauterine life and remain permanent during the whole life. Dermatoglyphics can be used as a diagnostic tool of genetically and nongenetically determined diseases. Thus, it can be used not only in the field of medicine but also in dentistry for the early identification or prediction of oral lesions and diseases. Hence the present paper reviews the application of dermatoglyphics in dentistry along with the advantages, limitations, and patterns of dermatoglyphics

Post salpingectomy intraluminal endometriosis in a premenopausal lady - an incidental finding often paid less attention to

Endometriosis of the fallopian tube is often incidentally picked up in hysterectomy specimens that are sent for histopathological examination for other obvious pathological conditions. Post-salpingectomy endometriosis is one such entity that is known to occur in the tip of the proximal stump of the fallopian tube years after tubal ligation. As mere visualization of the endometriotic lesions is inadequate for an accurate diagnosis, histopathologic analysis of the biopsy samples becomes mandatory for confirmation. We report a case of post salpingectomy endometriosis which was incidentally discovered in a peri menopausal lady who was operated for multiple fibroids of the uterus. This case not only highlights an entity which is challenging to visualize radiologically and suspect clinically, but is also underrecognized, as very little attention is given to the fallopian tube during routine grossing.

Goertler instability on an airfoil

An effective computational scheme was developed to study the growth/damping of Goertler vortices along walls of variable curvature. Computational experiments indicate that when the amplification rates for the u-, v-, and w-perturbations are the same, the finite difference approach to solve the initial value problem and the normal mode approach give identical results for the Blasius boundary layer on constant curvature concave walls. The growth of Goertler vortices was rapid in the concave regions and was followed by sharp damping in the convex region. However, multiple sets of counter-rotating vortices were formed and remained far downstream in the convex region. The current computational scheme can be easily extended to more realistic problems including variable pressure gradients and suction effects

Application of Platelet Rich Fibrin and Osseomold Bone Graft in Different Intrabony Defects – 2 Case Reports

ABSTRACT:    Aims & objectives: The motto behind any periodontal treatment is arrest of periodontal disease and regeneration of lost periodontium. Various treatment strategies have been employed in treatment of intrabony defects, but the best way to obtain regeneration is probably by mimicking the actual occurring events that takes place in the formation of the periodontal tissues at embryonic stage. Conventional open flap debridement falls short of regenerating tissues destroyed by the disease and current regenerative procedures offer a limited potential towards attaining complete periodontal regeneration.Platelet rich fibrin (PRF), a second generation platelet concentrate is widely used in osseous regeneration.Case description: The present study aimed to explore the clinical and radiographical effectiveness of autologous PRF along with the osseomold bone graft in treatment of 2 different cases of intrabony defects in chronic periodontics subjects.Conclusion: Among the 2 subjects, case-1 had 2-wall defect and case-2 patient had 3-wall defect. Both the subjects reported to the department with a complaint of food impaction and with clinically accessible >7-8mm pocket.  Pocket depth was assessed at 1st week, 6months and 9months respectively and radio graphically bone gain was accessed at 3 month and 6 months

MICROSTATELAB: The EEGLAB Toolbox for Resting-State Microstate Analysis.

Microstate analysis is a multivariate method that enables investigations of the temporal dynamics of large-scale neural networks in EEG recordings of human brain activity. To meet the enormously increasing interest in this approach, we provide a thoroughly updated version of the first open source EEGLAB toolbox for the standardized identification, visualization, and quantification of microstates in resting-state EEG data. The toolbox allows scientists to (i) identify individual, mean, and grand mean microstate maps using topographical clustering approaches, (ii) check data quality and detect outlier maps, (iii) visualize, sort, and label individual, mean, and grand mean microstate maps according to published maps, (iv) compare topographical similarities of group and grand mean microstate maps and quantify shared variances, (v) obtain the temporal dynamics of the microstate classes in individual EEGs, (vi) export quantifications of these temporal dynamics of the microstates for statistical tests, and finally, (vii) test for topographical differences between groups and conditions using topographic analysis of variance (TANOVA). Here, we introduce the toolbox in a step-by-step tutorial, using a sample dataset of 34 resting-state EEG recordings that are publicly available to follow along with this tutorial. The goals of this manuscript are (a) to provide a standardized, freely available toolbox for resting-state microstate analysis to the scientific community, (b) to allow researchers to use best practices for microstate analysis by following a step-by-step tutorial, and (c) to improve the methodological standards of microstate research by providing previously unavailable functions and recommendations on critical decisions required in microstate analyses