Stock Price Synchronicity and Voluntary Disclosure in Perspective of Pakistan

This study investigates the relationship between stock price synchronicity and voluntary disclosure in perspective of Pakistan. The degree of co-movement of stock price depends on the relative amount of firm-level and the wide market information. The aim of this study is to investigate the relationship between the degrees of firm’s information which is measured by voluntary disclosure levels and how much this firm-specific information is incorporated in the stock price, measured by synchronicity. We use 5-year data from Pakistan Stock Exchange for the period of 2010 to 2014 for KSE 100 index. We use SD-SCORE to measure the level of voluntary disclosure. SD-SCORE is calculated based on the information provided in firm’s annual reports. We assign points to each company based on five broad criteria. Additional points were given if firm provides quantitative data of some specific item used in the calculation of SD-SCORE. Further, R2 is used as a proxy of synchronicity which shows the level of information impounded into share prices. We regress synchronicity on voluntary disclosure level to find out whether it incorporates in share price or not. We conclude that in Pakistan, voluntary disclosure has a significant positive relation with stock price synchronicity. Our results suggest that not only public but also the private information incorporate in the stock price and provide inversely U-shape relationship between synchronicity and voluntary disclosure. The results of this study are based on multi-variant analysis, there is a significant positive relation between stock price synchronicity and firm’s voluntary disclosure levels

Gain Characterisation of 1.3μm GaAs Quantum Dot lasers

Gain characterisation of a laser device is of fundamental importance to assist in the physical understanding of laser materials. Not only does it determine important parameters such as threshold, material loss and transparency current density, but is also a vital source of information regarding the evolution of states as a function of current density and temperature. The differential gain (dg/dn) is of key importance in determining the dynamic performance of a laser. Hence, the important role of gain characterisation has driven researchers to devise improved techniques for spectral gain measurement. This thesis discusses the gain characterisation of 1.3μm quantum dot, commercial Innolume material and bi-layer laser devices. Initially, different gain measurement techniques are reviewed. High resolution spectroscopy and variable stripe length methods are analysed and compared in detail. A technical review is presented for the first time for the commonly used Hakki and Paoli, segmented contact and a new �integrated mode filter� method for gain measurement. Then the Hakki and Paoli method is used to perform high current density analysis of the gain spectrum of 1.3μm Innolume, quantum dot laser material under continuous wave drive conditions. The device is characterised with and without self-heating effects. The elimination of self-heating effects is achieved by using a longitudinal mode as a junction temperature monitor to keep the junction temperature constant. This allowed an unambiguous study of the continuous wave gain spectrum at average dot occupancy levels up to ~8 e-h pairs per quantum dot. A negative differential gain is observed in both cases. This is shown to be predominantly due to the free carrier effects. As a result, free-carrier related negative differential gain is observed for the first time. A variant to the segmented contact method, which utilises an integrated amplifier and mode filter is demonstrated for the first time. The measurement of the gain/absorption spectrum is critically compared under identical data acquisition conditions as for the integrated mode filter and segmented contact methods. By driving the amplifier section, it is possible to achieve ~3-dB of signal amplification. As a result the measurement of the gain spectrum is achieved over a broader spectral range. Further, it is shown that the integrated amplifier method enables gain measurements at lower current densities as compared to the standard technique. Lastly, the effect of inhomogeneous line width on the lasing line width of ~ 1.3μm quantum dot lasers is studied, as the line width of the transmitter is one of the key factors to determine the dispersion limit for optical communication systems. Two samples, with different inhomogeneous line width are compared under conditions where it is hoped that the effects of homogeneous line width and spectral hole burning are maintained at a constant level. This allows the effects of inhomogeneous line width alone to be studied. A ~30% reduction in inhomogeneous line width is shown to have a significant impact in reducing the lasing line width

Free Carrier Distribution Criterion in Quantum Dot Lasers

The spontaneous emission spectra of a 1.28?m InAs/GaAs QD (Quantum Dot) Fabry-Perot laser device has been measured under continuous wave operation at a fixed junction temperature of 300K. At low carrier densities, empirically observed static peak wavelength position and a fixed spectral shape of the spontaneous emission spectra are indicative of the random-like population distribution rather than a global Fermi level in the system. A theoretical model based on the Monte-Carlo method has been shown to have good agreement with the empirical results. In addition the evolutions of spontaneous emission spectral shapes are also explained in terms of many body effects

Stock Price Synchronicity and Voluntary Disclosure in Perspective of Pakistan

This study investigates the relationship between stock price synchronicity and voluntary disclosure in perspective of Pakistan. The degree of co-movement of stock price depends on the relative amount of firm-level and the wide market information. The aim of this study is to investigate the relationship between the degrees of firm’s information which is measured by voluntary disclosure levels and how much this firm-specific information is incorporated in the stock price, measured by synchronicity. We use 5-year data from Pakistan Stock Exchange for the period of 2010 to 2014 for KSE 100 index. We use SD-SCORE to measure the level of voluntary disclosure. SD-SCORE is calculated based on the information provided in firm’s annual reports. We assign points to each company based on five broad criteria. Additional points were given if firm provides quantitative data of some specific item used in the calculation of SD-SCORE. Further, R2 is used as a proxy of synchronicity which shows the level of information impounded into share prices. We regress synchronicity on voluntary disclosure level to find out whether it incorporates in share price or not. We conclude that in Pakistan, voluntary disclosure has a significant positive relation with stock price synchronicity. Our results suggest that not only public but also the private information incorporate in the stock price and provide inversely U-shape relationship between synchronicity and voluntary disclosure. The results of this study are based on multi-variant analysis, there is a significant positive relation between stock price synchronicity and firm’s voluntary disclosure levels

Implementation of early warning system in the clinical teaching unit to reduce unexpected deaths

Background Early detection of patients with clinical deterioration admitted to the hospital is critical. The early warning system (EWS) is developed to identify early clinical deterioration. Using individual patient’s vital sign records, this bedside score can identify early clinical deterioration, triggering a communication algorithm between nurses and physicians, thereby facilitating early patient intervention. Although various models have been developed and implemented in emergency rooms and paediatric units, data remain sparse on the utility of the EWS in patients admitted to general internal medicine wards and the processes and challenges encountered during the implementation.Local problem There is a lack of standardised tools to recognise early deterioration of patient condition.Methods This was a quality improvement project piloted in the clinical teaching unit of a tertiary care hospital. Data were collected 24 weeks pre-EWS and 55 weeks post-EWS implementation. A series of Plan, Do, Study, Act cycles were conducted to identify the root cause, develop a driver diagram to understand the drivers of unexpected deaths, run a sham test trial run of the EWS, educate and obtained feedback of clinical care teams involved, assess adherence to the EWS during the pilot project (6 weeks pre-EWS and 6 weeks post-EWS implementation), evaluate outcomes by extending the duration to 24 weeks pre-EWS and 55 weeks post-EWS implementation, and retrospectively review the uptake of the EWS.Interventions Implementation of a standardised protocol to detect deterioration in patient condition.Results During the pre-EWS implementation phase (24 weeks), there were 4.4 events per week (1.2 septic workups, 1.9 observation unit transfers, 0.7 critical care transfers, 0.13 cardiac arrests and 0.46 per week unexpected deaths). In the post-EWS implementation phase (55 weeks), there were 4.2 events per week (1.0 septic workup, 1.9 observation unit transfers, 0.82 critical care transfers, 0.25 cardiac arrests and 0.25 unexpected deaths).Conclusion The EWS can improve patient care; however, more engagement of stakeholders and electronic vital sign documentation may improve the uptake of the system

Power generation analysis of terrestrial ultraviolet-assisted solid oxide electrolyzer cell

This paper presents a novel system design that considerably improves the entrapment of terrestrial ultraviolet (UV) irradiance in a customized honeycomb structure to produce hydrogen at a standard rate of 7.57 slpm for places with a UV index > 11. Thermolysis of high salinity water is done by employing a solid oxide electrolyzer cell (SOEC), which comprises three customized, novel active optical subsystems to filter, track, and concentrate terrestrial UV solar irradiance by Fresnel lenses. The output of systems is fed to a desalinator, a photovoltaic system to produce electrical energy, and a steam generator with modified surface morphology to generate the required superheated steam for the SOEC. A simulation in COMSOL Multiphysics ver. 5.6 has shown that a customized honeycomb structure, when incorporated on the copper–nickel surface of a steam generator, improves its absorptance coefficient up to 93.43% (48.98%—flat case). This results in generating the required superheated steam of 650 °C with a designed active optical system comprising nine Fresnel lenses (7 m2) that offer the concentration of 36 suns on the honeycomb structure of the steam generator as input. The required 1.27 kW of electrical power is obtained by concentrating the photovoltaic system using In0.33Ga0.67N/Si/InN solar cells. This production of hydrogen is sustainable and cost effective, as the estimated cost over 5 years by the proposed system is 0.51 USD/kg, compared to the commercially available system, which costs 3.18 USD/kg

Desalination and Sterilization of Sea Water Using Active Optimized Optical Heat Concentration System

Solar-powered desalination holds the potential to meet rising water needs. Most of the global desalination methods require a lot of electrical energy that mostly comes from non-renewable energy resources, including coal, natural gas, and oil. Carbon emissions from these sources cause breathing problems and ozone depletion. An empirical study is performed to evaluate the optically active desalination process. The suggested mechanism moves the light funnel axially regardless of incident light intensity to maintain the water reservoir temperature to a fixed level to perform desalination. To reduce tracking error, control systems with the triple-axis movement of Fresnel lenses are developed using an optimization algorithm employing the least-squares criterion. It also maintains the temperature of the water reservoir at 250°C by absorbing total incident irradiance through a copper slab by incorporating a customized nano honeycomb layer. A textured glass surface on top of the reservoir reduces solar reflections. The light rays are concentrated by top Fresnel lenses, while the bottom Fresnel lens produces a parallel beam of concentrated light that falls on a copper slab inside the reservoir, vaporizing the desalinated water to maintain a clean water supply. Total dissolved solids (TDS), the potential of hydrogen (pH), and microbial measurements are made before and after the desalination process. To increase the rate of desalination and decrease the boiling point of water, a low-pressure suction pump is used. This low-cost and environmentally friendly project produces pure drinking water and could be installed at any location

Gain flattened S+C+L-band bidirectional thulium doped fiber/multi-section fiber optical parametric hybrid amplifier

This article demonstrates the achievement of optical amplification across the S, C, and L-bands. A hybrid amplifier is proposed that utilizes a combination of bidirectional thulium-doped fiber amplifier (TDFA) and multi-section fiber optical parametric amplifier. With careful selection of TDFA and parametric amplifier parameters, gain can be achieved over complementary bandwidth regions. Resultantly, better gain flatness is achieved over the whole effective bandwidth of 170 nm. The amplifier being proposed is evaluated for a system consisting of 18 wavelength division multiplexed channels, each with a capacity of 100 Gb/s, and a channel spacing of 10 nm. By setting the input power per channel to an optimal value of –30 dBm, the parameters are adjusted to attain a flat gain exceeding 23.52 dB, accompanied by a gain ripple of only 2.09 dB. These parameters are optimized over a wavelength range between 1460 nm and 1630 nm.Other Information Published in: Ain Shams Engineering Journal License: http://creativecommons.org/licenses/by-nc-nd/4.0/See article on publisher's website: https://dx.doi.org/10.1016/j.asej.2023.102497</p