Essays on Momentum, Autoregressive Returns, and Conditional Volatility: Evidence From the Saudi Stock Market

The objective of this dissertation is to examine different aspects of return behavior and provide an out of sample evidence from the Saudi stock market (SSM). It consists of three essays. The first essay is organized into two parts. In the first part, I investigate the relationship between momentum profitability and trading volume in the SSM. The objective of this part is to find out whether momentum strategies exist in the SSM and whether trading volume affects momentum profitability. In the second part, I investigate whether a 52-week high price momentum profitability exists in the SSM. The empirical results document the existence of price momentum strategy in the SSM. In addition, the momentum strategy is more profitable when it is conditioned on high volume stocks than when it is conditioned on low volume stocks. High volume winner portfolio drives the momentum profit in the SSM. However, the results on the 52 week-high price indicate a reversal in portfolio returns which contradicts the results of earlier study conducted in the U.S and Australian markets. The second essay examines the relationship between abnormal changes in trading volume of both firms and portfolio levels, and the short-term price autoregressive behavior in the SSM. The objective is to investigate the informational role that trading volume plays in predicting the direction of short-term returns. I evaluate whether the abnormal change in lagged, contemporaneous, and lead turnover affects serial correlation in returns. Consistent with the prediction of Campbell, Grossman, and Wang (1993) model, the result of this essay indicates that lagged abnormal change in trading volume lead to reversal in consecutive weekly returns. Contemporaneous and lead changes in volume provide mixing results. The third essay tests the effect of trading volume on the persistence of the time varying conditional volatility in the SSM. I utilize GARCH models to test the persistence of return volatility without volume, with contemporaneous volume, with lagged volume, and with two other alternative proxies of volume. This approach is applied to the market index, five industry indices, and 15 individual companies. In addition, this essay investigates the volatility spillover between size-based portfolios in the SSM using a two-stage GARCH approach. The results indicate that the SSM exhibit strong volatility persistence; however, when I include contemporaneous volume, the persistence vanishes, indicating that the rate of information arrival measured by the volume series can be a significant source of the conditional heteroskedasticity in SSM. The results show that the spillover effect is larger and statistically significant from large to small firm portfolios

The Effectiveness of multiple intelligence based differentiated instruction on metacognitive reading comprehension in Arabic language among middle school students in Saudi Arabia

Identifying an effective instructional strategy, such as this of  multiple intelligence based differentiated instruction to teach metacognitive reading comprehension is a goal for educators. The purpose of this study was to investigate the effectiveness  of  multiple intelligence based differentiated instruction on metacognitive reading comprehension in Arabic language among middle school students in Saudi Arabia. The sample consisted of 61 third year- middle school students , from Ibn Sina Middle school for boys , in Al-Kharj Governorate , Saudi Arabia. They were from two classrooms. They aged 14-15 years old ( M= 14.9 years , SD= 0.621) . For the purpose of this study and for  analyzing the data from the pre- and post-test, the author used two way  ANOVA analysis and t-test. Two way. ANOVA analysis and t-test results indicated the effectiveness of multiple intelligence based differentiated instruction on metacognitive reading comprehension in Arabic language among middle school students in Saudi Arabia. &nbsp

Implementation of Power-to-Gas to Reduce Carbon Intensity and Increase Renewable Content in Liquid Petroleum Fuels

Power-to-gas (PtG) is an emerging energy storage concept, which can transfer the surplus and intermittent renewable generated power into a marketable hydrogen, as well as providing other ancillary services for the electrical grid. In the case of Ontario, excess power is encountered during periods of low electricity demand as a result of substantial generation from baseload nuclear and increasing integration of intermittent renewable sources powering the electrical grid. This thesis develops various simulation and analysis of Ontario’s energy system to illustrate the use of PtG when its electrolytic hydrogen is employed in the gasoline production cycle to reduce the carbon intensity of the production process, and increase the renewable content of this traditional transportation fuel. The work includes a case study for a simulated refinery to evaluate the production cost and life cycle emission for different production scenarios, related to the deployment of polymer electrolyte membrane (PEM) electrolyzers to meet the refinery demand of hydrogen. Moreover, the study involves examining the use of the province surplus baseload generation (SBG) for which currently results in net exports to neighboring jurisdictions, and curtailed power generation capacity from wind and nuclear to meet the overall demand of the refining industry. Furthermore, a comparative assessment is conducted of blending 10% corn-ethanol and using electrolytic hydrogen supply via PtG on the ‘well to wheel’ (WTW) impacts of gasoline fuel, according to the metrics of total energy use, greenhouse gas emissions, and criteria air pollutants. According to the study, it is found that steam methane reforming (SMR) provides a lower cost hydrogen as a result of the current low natural gas prices, even with stringent carbon-pricing policy. However, the electrolytic hydrogen production shows a potential to curb significant carbon emissions as a substitute for SMR hydrogen. At a single refinery level, the use of electrolytic hydrogen can be compared to eliminating as many as 35,000 gasoline passenger vehicles from the road when there is an installation of 130 PEM electrolyzer units (1 MW nameplate capacity per unit). Also, the analysis shows that PtG has the potential to supply the refineries within the province with the entire hydrogen demand with a fraction of the surplus power, particularly when making use of available seasonal storage at least for the next four years. Moreover, PtG is found to decrease 4.6% of the natural gas consumption on the gasoline cycle, and increase the renewable content of gasoline by extending the utilization of wind and hydro power. Furthermore, the deployment of electrolytic hydrogen results in minimizing gasoline carbon intensity by 0.5 gCO2e per MJ of the fuel. When associated with the annual gasoline sales in Ontario, it can offer the reduction of 0.26 Megaton of greenhouse gas (GHG) emissions yearly. Moreover, PtG may contribute to lowering VOCs, NOx, PM10 and PM2.5 criteria air pollutants from gasoline cycle, which cannot be achieved with blending corn based ethanol. Accordingly, the results of this thesis outline the benefits of using power-to-gas to mitigate the existing issue of surplus power generation. Utilizing the excess electricity to produce hydrogen for refinery end user also increases the utilization of CO2 free energy and renewable content of gasoline within its life cycle production scheme

Job Satisfaction and Retention of Nursing Staff in Saudi Hospitals.

The objective of this study is to investigate job satisfaction amongst nurses in Saudi Arabian hospitals. In recent years, there has been considerable growth in the healthcare system in Saudi Arabia, yet little attention has been paid to improving the performance of healthcare professionals, by improving job satisfaction and retention of nursing staff. This paper reviews the research conducted on job satisfaction, and retention of Saudi nursing staff. This is an integrative review of previous studies on job satisfaction and retention of Saudi nursing staff. The electronic databases Google Scholar, CINAHL, PubMed, and Global Health were used to identify peer-reviewed literature published between 2009 and 2018.  The literature review showed that the majority of nurses were satisfied in their job. However, there was a shortage of research in retention of nurses. The evidence from this study suggests that the hospitals need to ensure high level of job satisfaction and decent wages of nurses for maximum retention of nurses. &nbsp

Appling tracking game system to measure user behavior toward cybersecurity policies

Institutions wrestle to protect their information from threats and cybercrime. Therefore, it is dedicating a great deal of their concern to improving the information security infrastructure. Users’ behaviors were explored by applying traditional questionnaire as a research instrument in data collocate process. But researchers usually suffer from a lack of respondents' credibility when asking someone to fill out a questionnaire, and the credibility may decline further if the research topic relates to aspects of the use and implementation of information security policies. Therefore, there is insufficient reliability of the respondent's answers to the questionnaire’s questions, and the responses might not reflect the actual behavior based on the human bias when facing the problems theoretically. The current study creates a new idea to track and study the behavior of the respondents by building a tracking game system aligned with the questionnaire whose results are required to be known. The system will allow the respondent to answer the survey questions related to the compliance with the information security policies by tracking their behavior while using the system

Overview On Surgical Management Of Overactive Bladder

Overactive bladder syndrome is a persistent and incapacitating disorder that has profound medical, psychological, and social implications, greatly impacting the wellbeing of countless individuals globally. A significant number of individuals experience urine urgency, which can be extremely bothersome. The primary indicator of overactive bladder (OAB) is a sense of urgency, often accompanied by increased urine frequency and nocturia. After ruling out other medical conditions with similar symptoms, the initial approach to managing OAB is providing guidance on fluid consumption and bladder training. If needed, antimuscarinic medicines may be added as a supplement. If patients have significant distress from OAB symptoms even after maximizing medicinal treatment, they may choose to undergo invasive procedures. There is currently a limited understanding of the hierarchical structure of central nervous system control. However, the use of functional imaging is starting to reveal the difficulties that need to be addressed in this area. Current research is exploring the use of botulinum neurotoxin-A injection, oral β3-adrenergic agonists, and innovative methods for nerve stimulation as potential therapies. The inherent subjectivity of urine urgency, the absence of animal models, and the complex pathophysiology of overactive bladder (OAB) pose substantial obstacles to achieving effective clinical therapy

Adenovirus and RNA-based COVID-19 vaccines’ perceptions and acceptance among healthcare workers in Saudi Arabia: a national survey

Objectives The aim of this study was to compare the perception, confidence, hesitancy and acceptance rate of various COVID-19 vaccine types among healthcare workers (HCWs) in Saudi Arabia, a nation with Middle East respiratory syndrome coronavirus experience. Design National cross-sectional, pilot-validated questionnaire. Setting Online, self-administered questionnaire among HCWs. Participants A total of 2007 HCWs working in the Kingdom of Saudi Arabia participated; 1512 (75.3%) participants completed the survey and were included in the analysis. Intervention Data were collected through an online survey sent to HCWs during 1–15 November 2020. The main outcome measure was HCW acceptance of COVID-19 candidate vaccines. The associated factors of vaccination acceptance were identified through a logistic regression analysis and via measurement of the level of anxiety, using the Generalised Anxiety Disorder 7 scale. Results Among the 1512 HCWs who were included, 62.4% were women, 70.3% were between 21 and 40 years of age, and the majority (62.2%) were from tertiary hospitals. In addition, 59.5% reported knowing about at least one vaccine; 24.4% of the participants were sure about their willingness to receive the ChAdOx1 nCoV-19 vaccine, and 20.9% were willing to receive the RNA BNT162b2 vaccine. However, 18.3% reported that they would refuse to receive the Ad5-vectored vaccine, and 17.9% would refuse the Gam-COVID-Vac vaccine. Factors that influenced the differential readiness of HCWs included their perceptions of the vaccine’s efficiency in preventing the infection (33%), their personal preferences (29%) and the vaccine’s manufacturing country (28.6%). Conclusions Awareness by HCWs of the several COVID-19 candidate vaccines could improve their perceptions and acceptance of vaccination. Reliable sources on vaccine efficiency could improve vaccine uptake, so healthcare authorities should use reliable information to decrease vaccine hesitancy among frontline healthcare providers

Transmission and evolution of the Middle East respiratory syndrome coronavirus in Saudi Arabia:a descriptive genomic study

BACKGROUND: Since June, 2012, Middle East respiratory syndrome coronavirus (MERS-CoV) has, worldwide, caused 104 infections in people including 49 deaths, with 82 cases and 41 deaths reported from Saudi Arabia. In addition to confirming diagnosis, we generated the MERS-CoV genomic sequences obtained directly from patient samples to provide important information on MERS-CoV transmission, evolution, and origin. METHODS: Full genome deep sequencing was done on nucleic acid extracted directly from PCR-confirmed clinical samples. Viral genomes were obtained from 21 MERS cases of which 13 had 100%, four 85-95%, and four 30-50% genome coverage. Phylogenetic analysis of the 21 sequences, combined with nine published MERS-CoV genomes, was done. FINDINGS: Three distinct MERS-CoV genotypes were identified in Riyadh. Phylogeographic analyses suggest the MERS-CoV zoonotic reservoir is geographically disperse. Selection analysis of the MERS-CoV genomes reveals the expected accumulation of genetic diversity including changes in the S protein. The genetic diversity in the Al-Hasa cluster suggests that the hospital outbreak might have had more than one virus introduction. INTERPRETATION: We present the largest number of MERS-CoV genomes (21) described so far. MERS-CoV full genome sequences provide greater detail in tracking transmission. Multiple introductions of MERS-CoV are identified and suggest lower R0 values. Transmission within Saudi Arabia is consistent with either movement of an animal reservoir, animal products, or movement of infected people. Further definition of the exposures responsible for the sporadic introductions of MERS-CoV into human populations is urgently needed. FUNDING: Saudi Arabian Ministry of Health, Wellcome Trust, European Community, and National Institute of Health Research University College London Hospitals Biomedical Research Centre

Improving critical infrastructure resilience with application to power distribution networks

Our modern societies are dependent on the functioning of infrastructure systems that support economic prosperity and quality of life. These infrastructure systems face an increasingly set of threats, natural or man-made disasters, that can cause significant physical, economic, and social disruptions. Recent extreme events have shown that total protection can not be accomplished. Therefore, Critical Infrastructure Protection strategies should focus not only on the prevention of these events but also on the response and recovery following them. This shift is realized by the concept of infrastructure resilience. In this thesis, we address the problem of assessing and improving infrastructure resilience. The contributions of this thesis focus on modelling, simulation, and optimization of infrastructure systems with respect to their resilience to extreme events. We first develop a resilience assessment framework for interdependent infrastructure systems. The developed framework provides a quantitative means to assess infrastructure resilience by introducing a generalized resilience index. To account for the inherent complexity due to infrastructure interdependencies, we use the i2Sim framework for modelling and simulating the studied infrastructure. The resilience improvement problem is formulated using the proposed resilience index as a resources allocation optimization problem. The problem aims at finding the best allocation of available resources such as power and water to mitigate the consequences of a disaster. Two solutions algorithm are proposed to solve the problem: the first one uses a simulation-optimization approach based on the Ordinal Optimization theory, and the second one uses a Linear Programming formulation. Results of both algorithms show that infrastructure resilience can be greatly improved by efficient allocations of available resources. In addition, a prioritization methodology is developed to assess decision makers to direct resilience investment to the most important components in the infrastructure. Finally, an optimal power distribution network reconfiguration algorithm is developed to complement the two resources allocation algorithms by solving the technical feasibility problem of the power distribution network. A heuristic computationally inexpensive optimization algorithm is developed based on Graph theory for solving this problem. The proposed algorithms are tested using different test cases and promising results are achieved.Applied Science, Faculty ofGraduat

Challenges to analysis of major, minor and trace elemental concentrations in two media of toxicological interest.

Since the industrial revolution pollution has typically been classified according to whether it concerns air, water or noise, the issue of light-pollution now joining these. Pollution, direct or otherwise, causes damage to the living environment. In the present study of moderate to high atomic number media, analysis of major, minor and trace elemental concentrations is shown to be effective via x-ray fluorescence and mass spectroscopy (MS) based methods. Particular choice has been made of two media of highly differing constitution, both of toxicological consequence and each with its own challenges. Metals are prevalent in the widespread environmental emissions that result from the use of motorised vehicles, not least in road dust. Conversely, the metals manifest in Kohl have been analysed as an example of how an absence of regulatory control can allow the unimpeded marketing of personal products of clear human health impact. In conducting such a study, comparison has been made of several sensitive yet convenient sample analysis techniques (XRF, SEM/EDX, ICP-MS and ICP-OES), their relative efficacy being examined. The ICP-based methods provide for quantitative sample analysis while XRF/EDX can provide quantitative and qualitative analysis. The XRF study of Kohl has involved analysis of Pb, Fe and Zn concentrations in 135 samples, obtained from nine randomly selected market outlets (15 aliquots of each brand being represented). Among the published physiological effects of exposure to Pb is replacement of Ca in bones and teeth, making them weak and fragile, other impacts including nephrotoxicity, linked with increased Pb blood levels. While in this study the work on Kohl formed an introduction to elemental analysis, one particular challenge, also one that quickly became apparent but yet notable in terms of its absence from discussion in the literature, was investigation of high concentrations of highly attenuating media. Sample dilution and account of it has been required in arriving at reliable quantification. One desire has been to draw regulator attention to the potentiality of convenient, compact instrumentation and associated methodology, allowing for product screening. For road dust, obtained from a total of 60 locations, analysis has been conducted on particle sizes ranging from < 45 m up to 125 m. Arid climate samples were collected from the campuses of King Saud University, the Kuwait Research Institute and Qatar University, while maritime climate samples were collected from the Surrey University campus. Ttropical climate samples were collected from the campus of the University of Malaya as well as surrounding roads to the Malaysian radiation consultancy company, Asia Lab (now Alypz Sdn. Bhd.). Roadside dirt has been sampled along busy campus roads of universities/research centres in Guildford, Riyadh, Kuwait City, Doha and Kuala Lumpur, satisfying interest in climatic influences as well as vehicle engine size (in the Gulf countries non-commercial vehicle engine capacities tend to be greater than those in the UK or Malaysia, a product of relatively cheap fuel prices). A total of 200 street dust samples have been analyzed, elemental concentrations being reported for Mg, Al, Ti, Mn, Fe, Co, Zr, Mo, Ba, Tl, V, Rd, Pb, Cu, Zn, Ni, Cr, Cd, As, Hg and Au. For all five urban centres, Al, Fe, Mg, and Si values were found to be well above background although concentrations of Ti, Cr and Ba were lower than values reported by others. The concentrations of Pb were relatively low, likely attributable to restrictions on lead in fuel. Au and Ag were detected in low quantities in both Arid and Maritime climates, use being made of the SEM/EDX, appearing at levels unlikely to make economic sense in terms of recovery. Note that elemental loadings are provided in terms of concentrations per unit mass of sample. In general, the elements found in elevated concentrations can all be linked to the wear and tear of motor parts as debris. For the Guildford samples, obtained at three different times of the year, the main SEM/EDX findings were for Mg, Al, Cr, Ti, Mn, Fe, Co, Cu, Zr, Mo, Ba, Tl, V, Rh, Au and Ag, values ranging from non-detectable (below detection limits), through to from as low as 34.7 E-6 mg/m2 up to as high as 6 E-2 mg/m2. Note that the output provides estimates of elemental loadings per unit area at the sampling site. Using ICP-MS, Guildford concentrations in mg/kg (ppm) have been found for Al, V, Cr, Mn, Fe, Co, Cu, Zn, As, Se, Mo, Cd, Sb, Pb, and U, for samples of mean size < 45 micron. Respective values were 3081, 12.3, 40.2, 333, 14133, 3.5, 70.4, 288, 5.96, 0.400, 2.35, 0.567, 2.77, 78.0, 0.657, results showing particular elevations of Al, Fe, Cu, Zn and Pb. Other toxic metals found in the Guildford and Kuwait samples in different concentrations were V, Ti, Cr, and Ba. For Riyadh and Doha samples four elements have been observed to be particularly prominent: Al, Fe, Mg, and Si, notwithstanding that they all have natural abundance in desert sands. Elemental presence has been seen to be influenced by climatic conditions as well as vehicle engine size. In conclusion, the various techniques offer complementary information on vehicular emission elemental concentrations in urban environments