Awareness and Knowledge Among Medical Students Regarding Lower Gastrointestinal Bleeding Etiologies in Riyadh, Saudi Arabia

Background: Lower gastrointestinal bleeding is known as hemorrhage which originates from the lower gastrointestinal system. Undergraduate students must have adequate knowledge of this topic to help them in their practice and to be effectively engaged with their patient’s assessment and diagnosis. Objectives: This study aims to assess the awareness and knowledge among medical students about lower gastrointestinal bleeding etiology in the governmental universities of Riyadh, Saudi Arabia. Materials and methods: This cross-sectional study was conducted using a prepared electronic self-reported questionnaire among medical students at four different universities in the Riyadh region. After collecting the data, MS Word was used for data entry while SPSS version 23 was used for data analysis. Results: In this study, a total number of 1,129 responses were collected from students at four different universities. Most of the participants (61.6%) were between 21-23 years old. In general, it was shown that 58.2% of students have enough knowledge regarding the symptoms related to lower gastrointestinal bleeding. Moreover, the participant medical students have chosen the hemorrhoids (33.2%) to be the leading cause followed by diverticulosis (20.0%), and anal fissures (11.1%). Conclusion: It was found that among the more than 1000 medical students in Riyadh region, Saudi Arabia, the awareness level toward symptoms and causes of lower GI bleeding is inadequate. There is a need to improve the awareness of medical students regarding lower GI bleeding presentation, particularly those in pre-clinical years

Evaluating Emission Reduction Due to a Proposed Light Rail Service: A Micro-Level Analysis

Carbon dioxide (CO2) alongside other gas emissions in the atmosphere cause a greenhouse effect, resulting in an increase of the average temperature of the planet. Transportation vehicles are among the main contributors of CO2 emission. Stationary vehicles with initiated motors produce more emissions than mobile ones. Intersections with traffic lights that force the vehicles to become stationary for a period of time produce more CO2 pollution than other parts of the road. This paper focuses on analyzing the CO2 produced by the traffic flow at Anzac Parade Road - Barker Street intersection in Sydney, Australia, before and after the implementation of Light rail transport (LRT). The data are gathered during the construction phase of the LRT by collecting the number of vehicles on each path of the intersection for 15 minutes during the evening rush hour of 1 week (6-7 pm, July 04-31, 2018) and then multiplied by 4 to calculate the flow of vehicles in 1 hour. For analyzing the data, the microscopic simulation software “VISSIM” has been used. Through the analysis, the traffic flow was processed in three stages: before and after implementation of light rail train, and one during the construction phase. Finally, the traffic results were input into another software called “EnViVer”, to calculate the amount of CO2 during 1 h. The results showed that after the implementation of the light rail, CO2 will drop by a minimum of 13%. This finding provides an evidence that light rail is a sustainable mode of transport

Macroscopic emission modelling for urban networks

An innovative methodology/framework has been proposed in this thesis for the effective application of well-known two-fluid model (TFM) on road emissions of urban networks to estimate the network-wide traffic-related emissions state at macroscopic level. This is demonstrated by developing an analytical model that illustrates the relationship between the parameters of the TFM and corresponding emissions of the traffic network. Hence the main contribution of this research study is the proposed hypothesis and consequently the formulation of a new model that estimates and evaluates the dynamic road emissions assessment at the network level in macroscopic manner. In addition, this study validates the feasibility of using the TFM to estimate vehicular emissions. The findings of the research are justified with two simulation experiments with two unique road networks. First network covers a part of Orlando downtown in United States, while the second network is artificial grid network with a number of roundabout intersections with uniform settings. The research approach is to analyse the performance of traffic for entire network which include number of roads, links and intersections excluding examining the performance of traffic intersection separately. Further investigations in this thesis were completed through empirical data collected from real case studies in order to discover the relation between the macroscopic fundamental diagram (MFD) properties (flow, density and speed) and road emissions

Morphometric Analysis of the Midline Mandibular Lingual Canal and Mandibular Lingual Foramina: A Cone Beam Computed Tomography (CBCT) Evaluation

Background: This study aimed to evaluate the midline mandibular lingual canals and foramina and their anatomic variations using CBCT scans. Methods: This study used retrospective analysis. A total of 320 CBCT scans were used to evaluate the study parameters, which comprised the presence or absence of the mandibular lingual foramen (MLF)/mandibular lingual canal (MLC) and its category, the distance between the buccal cortex and the start of the MLC, the distance between the inferior border of the mandible and the superior border of the foramen at its lingual and buccal terminals. The length and diameter of each canal at its lingual and buccal terminals. Results: MLC was found in all included CBCT scans. Out of 320 included CBCT scans, a single canal was represented by 30.9%, double canals (Supra with Infra -spinosum) configuration appeared in 54.7%, and triple canals (Supra-Inter-Infra) represented 14.7%. The supraspinosum canals averaged 5.81 ± 2.08 mm in length and 0.87 ± 0.30 mm in diameter at the lingual terminal. In terms of the number of canals, there was a significant difference between men and women (p ≤ 0.001), with 60% of the men in the sample having double canals and 43.1% of the women having single canals. Moreover, the male gender had a higher prevalence of triple canals (21.3% vs. 8.1%) than females. Males and females were distributed equally among the supraspinosum canals, with no statistically significant difference (p ≤ 0.7). A considerable increase in the finding of interspinosum and infraspinosum canals was seen in the male sample (p ≤ 0.001). Conclusions: midline mandibular canals were found in all investigated CBCTs of the sample of both sexes; however, the anatomy and location of the MLF and canals varied significantly among the Saudi population

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population