Analysis of high capacity short reach optical links

Over the last few years, the global Internet traffic has grown exponentially due to the advent of the social networks, high definition streaming, online gaming, high performance computing and cloud services. The network is saturating, facing a challenge to provide enough capacity to such ever-demanding bandwidth expensive applications. Fiber optic communications is the only technology capable of dealing such high demands due to its advantages over the traditional electrical transmission technology. The short haul transmissions currently rely on direct detection due to low cost, low power and low complexity as compared to the coherent detection schemes. In order to increase the bit rate, several advance modulation formats are under investigation for short reach transmissions. Such links mostly use intensity modulation direct detection (IMDD) schemes providing a simple system when compared with the coherent receivers. In this thesis the performance of Multilevel Pulse Amplitude Modulation (MPAM) is studied using IMDD, providing good spectral efficiency as well as able to deal with the limited electronic devices bandwidth. MPAM can address the typical optical channel without the need to go with more complex and higher power modulation schemes. It provides a trade off between sensitivity and the complexity. So a simple communication system using MPAM is implemented using an external modulated laser transmitted over a distance of 2 km. In order to reduce the cost, single laser and single receiver technique is being adopted. The performance of the MPAM system in a bandwidth limited scenarios is studied with a possibility to use equalization techniques to improve the sensitivity. The utility of Forward Error Correction codes is also studied to improve the performance without increasing the latency. By increasing the number of bits per symbol, the system becomes more sensitive to the impairments. Moreover, the components and the connectors in the transmission system also introduces multipath interference (MPI) that is a key limitation to the use of advance modulation formats. Hence a detailed study is carried out to investigate the MPI effects. At the end, a novel idea based on reflective Mach-Zehnder modulator (MZM) is presented that reuses the modulated wavelength eliminating the need for a laser. As a consequent, the cost and power consumption specifically targeted for the optical interconnect environment is reduced. In a nutshell, the thesis provides an overview of the direct detection system targeted to the short optical links. It includes the studies related to the optical transmission systems and provides an insight of the available advance modulation formats and the detection schemes. Finally, the simulations and laboratory results are provided showing that adoption of MPAM is a viable solution that should be employed in high capacity short reach optical links

Does an External Governance Framework Enhance the Performance of Pakistan's Banking Sectors? Foreign Ownership as Moderator

This study would determine how external governance structure improves the performance of listed banks in Pakistan with the return on assets (ROA), return on equity (ROE), earnings per share (EPS) and dividend payout ratio (DPR) estimates. The study concerned external corporate governance with the presence of foreign ownership as a moderator. The sample design of the study is listed banks in Pakistan stock exchange (PSX) from 2009 to 2018 with the availability of foreign ownership data. The data are gathered from financial statements, shareholding trends, and the credit rating agencies Pakistan (PACRA). The panel data approach (fixed and random effect model) was reversed to serve a different research objective and the study goals. The results showed that the external mechanism of governance performs an important part in the transparency and efficiency of the banking sectors. The banks could also increase foreign investment if they get better external governance mechanisms. This work will help commercial banks resolve the issues and improve compliance with the corporate governance code, and devise strategies for better functioning. This research is inconsistent as none defined the governance of the external system with the moderator presence in Pakistan

Effects of mutual coupling on gain and beam width of a linear array of a dielectric resonator antenna for main beam scanning applications

The effects of mutual coupling on the scanning characteristics of a four-element linear rectangular dielectric resonator antenna array (RDRA) are investigated for different inter-element spacing in this work. In particular, the gain and half-power beam width (HPBW) of an RDRA are studied for various scan angles in the E- and H-plane configurations. It is shown that for both the E and H planes, mutual coupling has an adverse effect on the performance of both phased array configurations. The H-plane array, however, is more stable than the E-plane array in terms of a gain and beam width performance comparison. The HPBW increases and gain decreases more in the E plane than the H plane when the scan angle is increased

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Genomic Profiling in Gynecological Carcinomas

ABSTRACTGynecological carcinomas, including ovarian, cervical, and endometrial cancers, pose significant challenges in clinical management and research due to their diverse molecular etiology. Ovarian carcinomas, particularly of epithelial origin, often arise from mutations in tumor suppressor genes like TP53 and oncogene overexpression, such as HER-2/neu and MYC. High-grade serous ovarian carcinoma (HGS-OC), the most prevalent subtype, exhibits TP53 mutations and alterations in homologous recombination DNA repair pathways. Additionally, endometrioid ovarian carcinomas result from dysregulation of the PI3K pathway and mutations in genes like PTEN and ARID1A. Cervical carcinomas predominantly stem from human papillomavirus (HPV) infection, disrupting key tumor suppressor pathways via oncoproteins E6 and E7. HPV-independent cervical carcinomas exhibit mutations in genes like PTEN and ARID1A. Endometrial carcinomas, arising from the endometrium, demonstrate diverse genetic alterations, including mutations in PTEN, PIK3CA, and TP53. Dysregulated signaling pathways such as PI3K/AKT/mTOR play crucial roles in endometrial cancer pathogenesis. Molecular profiling has led to the identification of subtype-specific biomarkers and therapeutic targets, improving personalized treatment approaches. Understanding the intricate molecular landscape of gynecological carcinomas is essential for advancing diagnostic strategies and developing targeted therapies to improve patient outcomes.Keywords: Medical Oncology, Gynecological carcinomas, Ovarian Cancer Management, Endometrial Cancer</p