Exploring Sentiment Analysis on Arabic Tweets about the COIVD-19 Vaccines

The COVID-19 pandemic has imposed a public health crisis across the world. The global efforts lead to the development and deployment of multiple vaccines. The success of ending the COVID-19 pandemic relies on the willingness of people to get the vaccines. Social media platforms prove to be a valuable source to perform experiments on sentiment and emotion towards COVID-19 vaccination in many languages, mainly focusing on English. The people express their opinions and emotion on Twitter briefly, which can have tracked almost instantaneously. This helps the governments, public health officials, and decision-makers to understand public opinions towards vaccines. The goal of this research is to investigate public sentiment on COVID-19 vaccines. Twitter social media extracted all Arabic-language tweets mentioning seven vaccines in 7 months from 1 November 2020 to 31 May 2021. A set of Arabic sentiment lexicons were prepared to perform the sentiment analysis. The tweets\u27 monthly average sentiment were calculated from the collected dataset and evaluated comparatively for each vaccine throughout the 11 months. Out of 5.5 million tweets that have been retrieved using the most frequent keywords and hashtags during the COVID-19 pandemic, 202,427 tweets were only considered and included in the monthly sentiment analysis. We considered tweets that mentioned only one vaccine name of the text. The distribution of tweets shows that 47.5% of the considered tweets mentioned the Pfizer vaccine. It is reported that 64% of the total tweets are non-negative while 35% are negative, with a significant difference in sentiment between the months. We observed an increase of non-negative tweets in parallel with increasing negative tweets on May 2021, reflecting the public\u27s rising confidence towards vaccines. Lexicon-based sentiment analysis is valuable and easy to implement the technique. It can be used to track the sentiment regarding COVID-19 vaccines. The analysis of social media data benefits public health authorities by monitoring public opinions, addressing the people\u27s concerns about vaccines, and building the confidence of individuals towards vaccines

A study on analysing mega-project failures in Saudi Arabia by using agency theory

Mega-projects are seen as a driving force for countries’ economies (Flyvbjerg et al., 2003; Kipp et al., 2008). However, the rate of project failure has never been greater and it has been argued that performance in mega-project management has not improved over the last 70 years (Flyvbjerg, 2017). In this context, this case study research investigates the time and cost-related failure of the Haramain High-speed Railway (HHR) mega-project in Saudi Arabia. The research question asked in this thesis is to what extent agency theory (AT), which posits the possibility of agent opportunism and is the primary theory in the thesis, can explain the HHR project’s failure. AT is seen as an appropriate theoretical lens for studying the case as the HHR project contains a series of complex principal-agent relationships. This prime theory is supported in the task of explaining the HHR project failure by two further subsidiary contextual theories; national cultural theory (CT) and project management theory (PMT). It was felt that, given the location and nature of the HHR project, it would be interesting to seek to understand the role of AT in explaining the HHR project failure in relation to the greater-utilised (within the project management literature) CT and PMT and in exploring the existence of overlaps between the theories. The research adopts a case study approach consisting of qualitative data. 38 interviews were undertaken with project participants from different organisations involved with the HHR project. This was supplemented by site observations and official documents in order to triangulate the findings. In the event, AT was found to be an underlying explanation for the failures observed in the HHR mega-project. Multiple agency problems (APs) were identified as major cause of failure. However, there were also other causes which were related to CT and PMT. These causes (especially those CT-related) were less significant to the HHR project failure, although the research discovered that there was actually some interrelation between the AT, CT and PMT causes of failure. The study makes a contribution to the project/mega-project management literature by extending the limited AT-related research on mega-projects, by looking at a more extensive range of principal-agent relationships than previous studies, by undertaking the first AT-related research into Saudi mega-projects and by establishing that some of the more established causes of project failure described in the literature can actually be contributors to, or consequences of, agent opportunism. This latter contribution highlights how the research’s use of AT points the way to greater theoretical generalisability in the study of the causes of mega-project failure

An Empirical Analysis of Behavioral Finance in the Saudi Stock Market: Evidence of Overconfidence Behavior

Theoretically, investors are considered to be rational decision makers in regards to trading in stock markets, however, some empirical studies have statistically discredited this believe. Evidence shows that investors seem to act irrationally in the financial markets. This research, therefore, aims to empirically investigate investor's irrational behavior, specifically, overconfidence behavior in the Saudi stock market, Tadawul. The data under investigation is from 2007 to 2018, monthly based. According to previous research, positive past market returns influence the level of investors' overconfidence leading to higher trading turnover in stock markets. To test for overconfidence behavior, a market-wide Vector autoregression (VAR) model is designed to investigate the lead-lag relationship between market returns and market turnover. The results obtained in this research suggest that investors in the Saudi stock market are overconfident. Keywords: Behavioral Finance, overconfidence bias, stock market, VAR JEL Classifications: D91, G11, G12, G15, E22, G4 DOI: https://doi.org/10.32479/ijefi.892

脳の発達におけるKIF3Bの機能に関する分子遺伝学的研究

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 岡部 繁男, 東京大学教授 河西 春郎, 東京大学教授 村上 誠, 東京大学講師 柳澤 春明, 東京大学教授 狩野 方伸University of Tokyo(東京大学

Unusual activity of rationally designed cobalt phosphide/oxide heterostructure composite for hydrogen production in alkaline medium.

Design and development of an efficient, nonprecious catalyst with structural features and functionality necessary for driving the hydrogen evolution reaction (HER) in an alkaline medium remain a formidable challenge. At the root of the functional limitation is the inability to tune the active catalytic sites while overcoming the poor reaction kinetics observed under basic conditions. Herein, we report a facile approach to enable the selective design of an electrochemically efficient cobalt phosphide oxide composite catalyst on carbon cloth (CoP-CoxOy/CC), with good activity and durability toward HER in alkaline medium (η10= -43 mV). Theoretical studies revealed that the redistribution of electrons at laterally dispersed Co phosphide/oxide interfaces gives rise to a synergistic effect in the heterostructured composite, by which various Co oxide phases initiate the dissociation of the alkaline water molecule. Meanwhile, the highly active CoP further facilitates the adsorption-desorption process of water electrolysis, leading to extremely high HER activity

In situ investigation of methane dry reforming on metal/ceria(111) surfaces: metal-support interactions and C-H bond activation at low temperature

Studies with a series of metal/ceria(111) (metal=Co, Ni, Cu; ceria=CeO2) surfaces indicate that metal–oxide interactions can play a very important role for the activation of methane and its reforming with CO2 at relatively low temperatures (600–700 K). Among the systems examined, Co/CeO2(111) exhibits the best performance and Cu/CeO2(111) has negligible activity. Experiments using ambient pressure X-ray photoelectron spectroscopy indicate that methane dissociates on Co/CeO2(111) at temperatures as low as 300 K—generating CHx and COx species on the catalyst surface. The results of density functional calculations show a reduction in the methane activation barrier from 1.07 eV on Co(0001) to 0.87 eV on Co2+/CeO2(111), and to only 0.05 eV on Co0/CeO2−x(111). At 700 K, under methane dry reforming conditions, CO2 dissociates on the oxide surface and a catalytic cycle is established without coke deposition. A significant part of the CHx formed on the Co0/CeO2−x(111) catalyst recombines to yield ethane or ethylene

The polygenic risk for bipolar disorder influences brain regional function relating to visual and default state processing of emotional information

Genome-wise association studies have identified a number of common single-nucleotide polymorphisms (SNPs), each of small effect, associated with risk to bipolar disorder (BD). Several risk-conferring SNPs have been individually shown to influence regional brain activation thus linking genetic risk for BD to altered brain function. The current study examined whether the polygenic risk score method, which models the cumulative load of all known risk-conferring SNPs, may be useful in the identification of brain regions whose function may be related to the polygenic architecture of BD. We calculated the individual polygenic risk score for BD (PGR-BD) in forty-one patients with the disorder, twenty-five unaffected first-degree relatives and forty-six unrelated healthy controls using the most recent Psychiatric Genomics Consortium data. Functional magnetic resonance imaging was used to define task-related brain activation patterns in response to facial affect and working memory processing. We found significant effects of the PGR-BD score on task-related activation irrespective of diagnostic group. There was a negative association between the PGR-BD score and activation in the visual association cortex during facial affect processing. In contrast, the PGR-BD score was associated with failure to deactivate the ventromedial prefrontal region of the default mode network during working memory processing. These results are consistent with the threshold-liability model of BD, and demonstrate the usefulness of the PGR-BD score in identifying brain functional alternations associated with vulnerability to BD. Additionally, our findings suggest that the polygenic architecture of BD is not regionally confined but impacts on the task-dependent recruitment of multiple brain regions

The influence of polygenic risk for bipolar disorder on neural activation assessed using fMRI

Genome-wide association studies (GWAS) have demonstrated a significant polygenic contribution to bipolar disorder (BD) where disease risk is determined by the summation of many alleles of small individual magnitude. Modelling polygenic risk scores may be a powerful way of identifying disrupted brain regions whose genetic architecture is related to that of BD. We determined the extent to which common genetic variation underlying risk to BD affected neural activation during an executive processing/language task in individuals at familial risk of BD and healthy controls. Polygenic risk scores were calculated for each individual based on GWAS data from the Psychiatric GWAS Consortium Bipolar Disorder Working Group (PGC-BD) of over 16 000 subjects. The familial group had a significantly higher polygene score than the control group (P=0.04). There were no significant group by polygene interaction effects in terms of association with brain activation. However, we did find that an increasing polygenic risk allele load for BD was associated with increased activation in limbic regions previously implicated in BD, including the anterior cingulate cortex and amygdala, across both groups. The findings suggest that this novel polygenic approach to examine brain-imaging data may be a useful means of identifying genetically mediated traits mechanistically linked to the aetiology of BD

Assessing the efficacy of a bioflavonoid-based mouth rinse in reducing oral malodor related to removable orthodontic appliances in comparison to chlorhexidine

Halitosis is an unpleasant breath odor; it affects roughly 30-50% of the population. The major compounds that contribute to halitosis that originates from the mouth, typically referred to as oral malodor, are volatile sulfur compounds (VSCs), which are produced by a variety of microorganisms. It has been shown that orthodontic patients with acrylic appliances complain of oral malodor. The source of the odor is in part due to the nature of the appliance, which retains microorganisms that are not removed by mechanical cleaning so typically the addition of an antimicrobial agent, such as Chlorhexidine (CHX) to cleanse the appliances is recommended. However, CHX has some side effects so alternatives need to be explored. Objective: To assess the antimicrobial and the anti-malodor efficacy of a bioflavonoid mouth rinse (BFMR) compared to CHX and water on removable orthodontic appliances. Method: Participants between 8-20 years of age who complained of malodor from their removable orthodontic appliances from the UBC dental clinics and a private orthodontic practice were recruited and blindly randomized into groups in which different mouth rinses were used to soak the appliances for one week (BFMR, Chlorhexidine and water). Baseline and one-week follow-up data collection included the oral hygiene index (OHI), gingival index (GI), tongue coating index (TCI), VSC measurement by gas chromatography, organoleptic assessment, a microbial swab Results: Data was collected from 27 participants ranging in age from 8-16 years old. The baseline measurements of OHI, GI and TCI did not change significantly throughout the study. The organoleptic measurements of odor as well as the aerobic and anaerobic bacterial counts showed a significant reduction in the BFMR group, but for the CHX and water group no significant difference was detected from baseline to follow-up. Conclusion: The BFMR has superior antimicrobial and anti-malodor effect when compared to CHX or to water.Dentistry, Faculty ofGraduat

Establishing methods to screen novel small molecules targeting insulin-like growth factor/insulin-like growth factor binding protein interaction

Insulin-like growth factors (IGFs) are important systemic mediators of growth and survival that suppress apoptosis and promote cell cycle progression, angiogenesis and metastatic activities in various cancers by activating IGF-IR tyrosine kinase-mediated signaling. These effects depend on the bioavailability of IGFs, which is regulated by IGF binding proteins (IGFBPs). Increased IGFBP-2 and IGFBP-5 expression observed in castration-resistant prostate cancer is thought to promote tumor progression by enhancing IGF-mediated signaling. IGFBPs have cooperative carboxy-terminal and amino-terminal low and a high affinity IGF binding sites. I hypothesize that blocking the high affinity IGF binding site can affect the bioavailability of IGFs to target tissues and thus be used for treatment of various IGF-responsive diseases including prostate cancer. I initially characterized immunologic reagents capable of being used in sandwich ELISA formats to detect IGF-I and IGFBP-5 and attempted several configurations to establish an IGF-I/IGFBP-5 “bridged” sandwich ELISA platform to measure association and dissociation of IGF-I/IGFBP-5 complex formation. The inability of all bridged ELISA formats tested to measure IGF-I/IGFBP-5 binding, lead me to developed a Bio-Layer Interferometry-based assay that measures IGF-I/ IGFBP-5 binding kinetics that will allow for screening of factors that can affect this intermolecular interaction. I demonstrated that biotinylated IGF-I bound to streptavidin-coated biosensors can be used to measure binding of recombinant IGFBP-5 [2.24 nm shift in optical density (Response)]. I also demonstrated that IGF-I could efficiently disrupt this interaction (0.21 nm shift), while the amino-terminal IGF-I mutant, E3R, exhibits an intermediate competitive activity (1.47 nm shift) and insulin exhibits a low competitive activity (1.83 nm shift). In addition, I demonstrated that IGF-I can competitively disrupted this interaction, resulting in a dissociation rate constant (Kdis 1.5-³ 1/s), In contrast, the amino terminal IGF-I mutant, E3R binds with an intermediate affinity (Kdis 5.6-⁴ 1/s), and buffer free sample results in a (Kdis) of 1.5-⁴ (1/s). These results demonstrate the capacity of this BLI-based assay to differentiate relative competitive activity of compounds that target the high affinity IGF-I binding site of IGFBPs and establish a platform to screen for factors that might be developed as rationale therapeutics to disrupt sequestration of IGF-I by IGFBPs.Surgery, Department ofMedicine, Faculty ofGraduat