Optimal Timer Based Selection Schemes

Timer-based mechanisms are often used to help a given (sink) node select the best helper node among many available nodes. Specifically, a node transmits a packet when its timer expires, and the timer value is a monotone non-increasing function of its local suitability metric. The best node is selected successfully if no other node's timer expires within a 'vulnerability' window after its timer expiry, and so long as the sink can hear the available nodes. In this paper, we show that the optimal metric-to-timer mapping that (i) maximizes the probability of success or (ii) minimizes the average selection time subject to a minimum constraint on the probability of success, maps the metric into a set of discrete timer values. We specify, in closed-form, the optimal scheme as a function of the maximum selection duration, the vulnerability window, and the number of nodes. An asymptotic characterization of the optimal scheme turns out to be elegant and insightful. For any probability distribution function of the metric, the optimal scheme is scalable, distributed, and performs much better than the popular inverse metric timer mapping. It even compares favorably with splitting-based selection, when the latter's feedback overhead is accounted for.Comment: 21 pages, 6 figures, 1 table, submitted to IEEE Transactions on Communications, uses stackrel.st

Laparoscopic management of an endometrioma complicated by an ovarian abscess

An ovarian abscess is defined as a primary infection of the ovary without the involvement of the fallopian tube. The possible factors for the cause of ovarian abscess are: disruption of the ovarian capsule, giving access to bacteria, haematogenous and lymphatic spread. A woman with a ruptured ovarian abscess presents with features of diffuse peritonitis. An unruptured abscess is more difficult to diagnose. Unruptured abscess can be dealt with either laparotomy or laparoscopy. Ruptured ovarian abscess requires an aggressive and primarily surgical approach.

Evaluation of the effect of topical cefadroxil on bacterial load of pathogenic staphylococci in anterior nares in human volunteers, comparative study between oral vs. topical cefadroxil and evaluation of effect of combination of oral plus topical cefadroxil in patients with staphylococcal superficial skin infections

Background: Cefadroxil has good tissue penetration & exerts more sustained action at the site of infection after oral absorption. Our aim of the study was to check topical cefadroxil has any efficacy over staphylococcal superficial skin infection or not.Methods: Pre-treatment nasal swabs were obtained from 25 healthy human volunteers and bacterial load was recorded. After single application of topical cefadroxil 3% in left anterior nare and placebo (vehicle) in right anterior nare nasal swabs were obtained and results were compared. 150 patients with staphylococcal superficial skin infections were distributed in 4 groups: Group A - oral cefadroxil 500 mg twice daily for 5 days, Group B - topical cefadroxil (0.5 % to 5%) twice daily, Group C - cefadroxil 500 mg orally plus placebo (vehicle) topically twice daily and Group D -cefadroxil 500 mg orally plus cefadroxil preparation topically twice daily. Bacterial load was measured before treatment, on follow up &after clinical cure and results were compared.Results: Topical cefadroxil significantly reduced bacterial load after single application in anterior nare. Topical cefadroxil cured and significantly reduced bacterial load in staphylococcal superficial skin infections within 3 days of treatment. Oral plus topical cefadroxil combination therapy significantly reduced bacterial load and cured infection within 3 days of treatment in patients with moderate to heavy bacterial growth. No any adverse effect was observed during entire study period in any of groups.Conclusions: Topical preparation of cefadroxil is safe and effective in treating staphylococcal superficial skin infections. Combination of oral plus topical cefadroxil showed synergistic effect in infections with moderate to heavy growth. This study is registered at CTRI [REG ID: CTRI/2013/02/003433 REF: REF/2013/02/004576]

A Comparative Analysis of Field Oriented Control and Direct Torque Control of Induction Motor Drive

Electric Motor Drive System is employed in the various industrial applications such as pumping, air blowing, cooling and compression refrigeration. The motor drive speed control can be achieved by variety of techniques, but an emerging one is Variable Frequency Drive System (VFDS). The motor driven equipment on a typical industrial site accounts for approximately two thirds of the electricity consumption. Now-a-days induction motor is the main work-horse of the industries. So controlling of performance of induction motor is most precisely required in many high performance applications. Scalar control method gives good steady state response but poor dynamic response. While vector control method gives good steady state as well as dynamic response. But it is complicated in structure so to overcome this difficulty, direct torque control introduced. This paper discusses the comparative analysis of Field Oriented Control (FOC) and Direct Torque Control (DTC) methods of Polyphase Induction Motor (PIM) according to their working principle, structure complexity, performance, merits and demerits

Higher plasma CXCL12 levels predict incident myocardial infarction and death in chronic kidney disease: findings from the Chronic Renal Insufficiency Cohort study

Aims Genome-wide association studies revealed an association between a locus at 10q11, downstream from CXCL12, and myocardial infarction (MI). However, the relationship among plasma CXCL12, cardiovascular disease (CVD) risk factors, incident MI, and death is unknown. Methods and Results We analysed study-entry plasma CXCL12 levels in 3687 participants of the Chronic Renal Insufficiency Cohort (CRIC) Study, a prospective study of cardiovascular and kidney outcomes in chronic kidney disease (CKD) patients. Mean follow-up was 6 years for incident MI or death. Plasma CXCL12 levels were positively associated with several cardiovascular risk factors (age, hypertension, diabetes, hypercholesterolaemia), lower estimated glomerular filtration rate (eGFR), and higher inflammatory cytokine levels (P \u3c 0.05). In fully adjusted models, higher study-entry CXCL12 was associated with increased odds of prevalent CVD (OR 1.23; 95% confidence interval 1.14, 1.33, P \u3c 0.001) for one standard deviation (SD) increase in CXCL12. Similarly, one SD higher CXCL12 increased the hazard of incident MI (1.26; 1.09,1.45, P \u3c 0.001), death (1.20; 1.09,1.33, P \u3c 0.001), and combined MI/death (1.23; 1.13–1.34, P \u3c 0.001) adjusting for demographic factors, known CVD risk factors, and inflammatory markers and remained significant for MI (1.19; 1.03,1.39, P = 0.01) and the combined MI/death (1.13; 1.03,1.24, P = 0.01) after further controlling for eGFR and urinary albumin:creatinine ratio. Conclusions In CKD, higher plasma CXCL12 was associated with CVD risk factors and prevalent CVD as well as the hazard of incident MI and death. Further studies are required to establish if plasma CXCL12 reflect causal actions at the vessel wall and is a tool for genomic and therapeutic trials

Signal-to-noise measurements utilizing a novel dual-energy multimedia detector

Dual-energy measurements are presented utilizing a novel slot-scan digital radiographic imaging detector, operating on gaseous solid state ionization principles. The novel multimedia detector has two basic functional components: a noble gas-filled detector volume operating on gas microstrip principles, and a solid state detector volume. The purpose of this study is to investigate the potential use of this multimedia detector for enhanced dual-energy imaging. The experimental results indicate that the multimedia detector exhibits a large subtracted signal-to-noise ratio. Although the intrinsic merit of this device is being explored for medical imaging, potential applications of the multimedia detector technology in other industrial areas, such as aerospace imaging, aviation security, and surveillance, are also very promising