Design and Analysis of Self-Healing Tree-Based Hybrid Spectral Amplitude Coding OCDMA System

This paper presents an efficient tree-based hybrid spectral amplitude coding optical code division multiple access (SAC-OCDMA) system that is able to provide high capacity transmission along with fault detection and restoration throughout the passive optical network (PON). Enhanced multidiagonal (EMD) code is adapted to elevate system’s performance, which negates multiple access interference and associated phase induced intensity noise through efficient two-matrix structure. Moreover, system connection availability is enhanced through an efficient protection architecture with tree and star-ring topology at the feeder and distribution level, respectively. The proposed hybrid architecture aims to provide seamless transmission of information at minimum cost. Mathematical model based on Gaussian approximation is developed to analyze performance of the proposed setup, followed by simulation analysis for validation. It is observed that the proposed system supports 64 subscribers, operating at the data rates of 2.5 Gbps and above. Moreover, survivability and cost analysis in comparison with existing schemes show that the proposed tree-based hybrid SAC-OCDMA system provides the required redundancy at minimum cost of infrastructure and operation

Study protocol of DIVERGE, the first genetic epidemiological study of major depressive disorder in Pakistan

INTRODUCTION: Globally, 80% of the burdenof major depressive disorder (MDD) pertains to low- and middle-income countries. Research into genetic and environmental risk factors has the potential to uncover disease mechanisms that may contribute to better diagnosis and treatment of mental illness, yet has so far been largely limited to participants with European ancestry from high-income countries. The DIVERGE study was established to help overcome this gap and investigate genetic and environmental risk factors for MDD in Pakistan. METHODS: DIVERGE aims to enrol 9000 cases and 4000 controls in hospitals across the country. Here, we provide the rationale for DIVERGE, describe the study protocol and characterise the sample using data from the first 500cases. Exploratory data analysis is performed to describe demographics, socioeconomic status, environmental risk factors, family history of mental illness and psychopathology. RESULTS AND DISCUSSION: Many participants had severe depression with 74% of patients who experienced multiple depressive episodes. It was a common practice to seek help for mental health struggles from faith healers and religious leaders. Socioeconomic variables reflected the local context with a large proportion of women not having access to any education and the majority of participants reporting no savings. CONCLUSION: DIVERGE is a carefully designed case-control study of MDD in Pakistan that captures diverse risk factors. As the largest genetic study in Pakistan, DIVERGE helps address the severe underrepresentation of people from South Asian countries in genetic as well as psychiatric research

PhD

dissertationThe potential role of various neurotransmitter systems was investigated in the phenomenon of amphetamine-induced reverse tolerance. CF-1 mice were treated daily with amphetamine to produce reverse tolerance to the stereotypic effects of the drug. After amphetamine withdrawal, the enhanced responsiveness characteristic of reverse tolerance persisted for at least 28 days. Associated with reverse tolerance were changes in the glutamate, GABA and serotonin systems, as measured by a decrease in convulsive threshold to N-methyl-DL-aspartate (NMDLA), an increase in convulsive threshold to bicuculline, and an increase responsiveness to 5-hydroxytryptophan in the head-twitch test. In contrast, no changes were observed in the thresholds to arecoline-, strychnine- or aminophylline-induced convulsions. The changes in the NMDLA and Bicuculline convulsive thresholds, like reverse tolerance itself, were persistent after amphetamine withdrawal; in contrast, the functional responsiveness of the serotonin system returned to normal within 15 days. Daily pretreatment with the dopaminergic blocker haloperidol or with the N-methyl-D-aspartate antagonists MK-801 or ketamine blocked the development of the reverse tolerance. Pretreatment with haloperidol, MK-801 or ketamine also prevented the changes in convulsive threshold to NMDLA and bicuculline. Pretreatment with the GABAergic drug diazepam or the serotonin antagonist cyproheptadine had no effect on the development of reverse tolerance or changes in the NMDLA or Bicuculline convulsive thresholds. The results from these studies illustrate that the development of reverse tolerance to amphetamine involves not only the dopaminergic but also the glutamatergic system

Epidemiological Aspects of Giant Cell Arteritis

Giant cell arteritis (GCA) is a systemic vasculitis that affects medium-to-large-sized arteries, in which the inflammatory reaction destroys the artery wall with the fragmentation of the elastic lamina. Such phenomena can result in vision loss if not treated promptly. Other nonocular symptoms noted include GCA, headache, tenderness in the temporal area of the scalp, myalgias and arthralgias, fever, weight loss, and jaw claudication. Clinical suspicion is an essential pathway to the diagnosis of this disease. Thus, immediate Westergren sedimentation rate and C-reactive protein should be obtained. A temporal artery biopsy, however, remains the most definitive diagnostic tool. The incidence of GCA remarkably increases with each decade of age among those aged 50 years or over. Additionally, there have been notable differences among patients of different ethnicities. The epidemiological characteristics of GCA have been primarily researched in populations from the United States as well as several European countries with emphasis on the Caucasian population. In more recent years, a handful of studies have emerged from non-European countries regarding the epidemiology of GCA. The results of these findings are in parallel with previous observations, which presumed GCA to be more common in European and North American populations