Understanding the movement, direction, and shape of sand dunes can contribute to reducing their impact on infrastructure and the environment. The Rub’ al Khali desert has a distribution of dune ...types. This study aims to identify and map the different types of dunes within the Rub’ al Khali using a texture analysis method based on a digital elevation model (DEM). Statistical texture analysis methods (variance, skewness, and kurtosis) show three different textures of sand dune shapes, according to the geography of the dunes, using data contained in global DEMs. The analysis presented in this study focused on the use of DEMs to investigate the varied dune morphology within the Rub’ al Khali. The GMTED2010 and EarthEnv_DEM90 digital elevation models were compared. Spatial variability in dune height, spatial variability in dune texture, and profile graphs were created to examine dune surfaces in cross-section. The results provided six different dune types within the sand sea: giant compound linear dunes, simple linear dunes, simple transverse dunes, compound crescentic dunes (megabarchans), huge star dunes, and many transitional forms that defy classification. The results showed that the compound linear dune and simple linear dune were the dominant dune types, covering 41.61% and 31.7% of the total study area, respectively. The maps of variance, using either 10 × 10 and 30 × 30 focal blocks, produced a fairly sharp distinction in dune texture. It is hoped that future research in aeolian geomorphology will greatly benefit from these results, which could easily be expanded with the use of more sophisticated pattern recognition software, which clearly shows the value of using such an approach.
The Rub’ al Khali desert (or Empty Quarter) is the largest and perhaps most significant sand sea in the world. Located on the southern Arabian Peninsula, the dune field has remained largely ...unexplored owing to the harsh clime and difficult terrain. This study takes advantage of geospatial technology (interpolations, supervised classification, minimum focal statistic) to extract information from the data contained in global Digital Elevation Model (DEM)s, satellite imagery. The main objective here is to identify and map different dune forms within the sand sea, estimate the volume of sand and explore probable sources of sand. The analysis of dune color strongly suggests that the sand is not completely reworked and intermixed. If this is true, a spatial variability map of the mineral composition of the sand could be very revealing. The red sand is quite pronounced, the largest volume of sand (~36%) is associated with the yellow color class. Yellow sand covers most of the western part of the dunes field and seems to be a transitional color between red and white sand in the eastern part of the dune field. This suggests that the yellow sand might be derived from both local and regional sources, or it might be less oxidized, reworked, or have a different composition that represents a combination of red and white sand.
The Al-Asfar surface area during minimum, intermediate, and maximum water levels was compared from Landsat satellite images corresponding to 1988, 2001, and 2015. In this research, two stages were ...applied for the remote sensing data, first, unsupervised classification with the
k
-means algorithm, and the second vegetation index is the normalized difference vegetation index (NDVI). For the best discrimination between the water, land, and vegetation and to validate the results using a high spatial resolution image from Spot 6, a remote sensing technique was used, including a comparison of unsupervised classification and short-wave infrared thresholding techniques on Landsat images and Spot. The results of the water surface area for both the reference image (Spot) and OLI 2017 for the three parts of the lake are shown. The results of the water surface area in the first part are almost equal to those of both the reference image and OLI, where the area is estimated to be approximately 6.7 km
2
and 6.84 km
2
, respectively. The perimeter of the first part gradually increased from 1988 to 2015, whereas the second part showed a noticeable difference in the perimeter during different years, such as 1988, which was estimated to have the smallest perimeter. The total perimeter length for 2015, 2001, and 1988 was 109.37, 143, and 63.25 km, respectively. Finally, this study recommended measuring the water quality of this evaporating lake, such as the chemical, physical, and biological statuses using similar data and techniques.
COVID-19 is a disease-causing coronavirus strain that emerged in December 2019 that led to an ongoing global pandemic. The ability to anticipate the pandemic’s path is critical. This is important in ...order to determine how to combat and track its spread. COVID-19 data is an example of time-series data where several methods can be applied for forecasting. Although various time-series forecasting models are available, it is difficult to draw broad theoretical conclusions regarding their relative merits. This paper presents an empirical evaluation of several time-series models for forecasting COVID-19 cases, recoveries, and deaths in Saudi Arabia. In particular, seven forecasting models were trained using autoregressive integrated moving average, TBATS, exponential smoothing, cubic spline, simple exponential smoothing Holt, and HoltWinters. The models were built using publicly available daily data of COVID-19 during the period of 24 March 2020 to 5 April 2021 reported in Saudi Arabia. The experimental results indicate that the ARIMA model had a smaller prediction error in forecasting confirmed cases, which is consistent with results reported in the literature, while cubic spline showed better predictions for recoveries and deaths. As more data become available, a fluctuation in the forecasting-accuracy metrics was observed, possibly due to abrupt changes in the data.
In the midst of global efforts to curb the spread of infectious diseases, researchers worldwide are striving to unravel the intricate spatial and temporal patterns of disease transmission dynamics. ...Mathematical models are indispensable tools for understanding the dissemination of emerging pathogens and elucidating the evolution of epidemics. This paper introduces a novel approach by investigating city transmission networks as a framework for analyzing disease spread. In this network, major cities are depicted as nodes interconnected by edges representing disease transmission pathways. Subsequent network analysis employs various epidemiological and structural metrics to delineate the distinct roles played by cities in disease transmission. The primary objective is to identify superspreader cities. Illustratively, we apply this methodology to study COVID-19 transmission in Saudi Arabian cities, shedding light on the specific dynamics within this context. These insights offer valuable guidance for decision-making processes and the formulation of effective intervention strategies, carrying significant implications for managing public health crises.
IntroductionHerpes zoster (HZ) is a viral infection that occurs due to the reactivation of the varicella-zoster virus (VZV). Reactivation of the latent virus causes a painful dermatomal rash that is ...typical in HZ, which is frequently accompanied by post-herpetic neuralgia (PHN). Although HZ negatively impacts individuals’ quality of life, vaccination has been shown to reduce the incidence of HZ and PHN and reduce the severity of the disease in the event of a breakthrough. Nonetheless, several studies have shown a low level of knowledge and poor practices regarding HZ and its vaccine. However, only two studies on this issue have been conducted in the Middle East. This study aimed to assess the level of knowledge, attitudes, and practices toward HZ vaccinations among the Saudi population aged 50 years and older.MethodsA cross-sectional observational study was conducted from December 2022 to July 2023 involving citizens aged 50 years and older in Saudi Arabia. Data were collected using an online, validated, close-ended structured questionnaire distributed through social media. Linear regression analysis was used to assess independent predictors of knowledge regarding HZ, knowledge regarding the HZ vaccine, and attitudes toward HZ. Categorical variables were dummy-coded. Binary logistic regression was used to assess factors associated with the willingness to receive the HZ vaccine.ResultsA total of 368 respondents completed the questionnaire. The mean knowledge scores (%) regarding HZ and its vaccine were 28.6% and 37.1%, respectively. While 51.6% (n = 190) claimed to be aware of the HZ vaccine, only 31.6% (n = 60) had a knowledge score of 80% or higher. Multivariate analysis showed that knowledge was positively associated with female gender, prior chickenpox infection, and higher education. Only 54.4% of the respondents were willing to get the HZ vaccine, and 28.8% were willing to pay out of pocket for the HZ vaccine.ConclusionThe results suggest that educational campaigns on HZ and its vaccine targeting at-risk groups are required to raise awareness and increase the public’s knowledge. Additionally, healthcare personnel's recommendation of the HZ vaccine to the target population should be encouraged, as it is an important factor in vaccine acceptability.
is a key pathogen causing several gastrointestinal diseases. Fortunately,
infection is treatable, which can lower its comorbidities. However, data assessing physicians' awareness of
is lacking in ...Saudi Arabia.
To assess the knowledge and awareness of physicians of different specialties who practice in Saudi Arabia about
infection.
This is a cross-sectional study conducted between May and September 2022 on physicians across all regions in Saudi Arabia using a validated online questionnaire covering their knowledge and awareness of
infection. An independent
-test, one-way ANOVA, and Games-Howell as a post hoc test were used to analyze the data. A General Linear Model was also employed to determine significant predictors among the variables reliant on
awareness.
The results showed that the mean awareness score of 474 physicians was 76.99± 6.9, indicating that participants had sufficient knowledge about
infection. In general, the internal medicine specialists (28.3%) had better awareness of
infection than the other specialties. Moreover, the university hospital sector performed the best, scoring 80.68±13.3, and the southern region had the highest-ranked physicians with a score of 81.56 ±13.7 in terms of
awareness. Furthermore, the general linear model revealed a statistical significance (p<0.05) for the following demographic aspects concerning
awareness: the physicians' age group of 30-39 years, duration of experience of 11-15 years, the hospital sectors of Nation Guards (NGH) and Security Forces (SFH), and the southern and central regions of practice in Saudi Arabia.
Physicians in Saudi Arabia have relatively sufficient awareness of
; however, they are highly influenced by age, years of experience, the hospital sector involved, and the region where the physicians practice.
Introduction: The incidence of nontraumatic spinal cord injury (NTSCI) is reported to be higher than that of traumatic spinal cord injury in many countries, making it an area of growing significance. ...Objectives: With the aging of the global population in coming decades, it is anticipated that the incidence of NTSCIs will increase dramatically. Our aim was to identify and report the causes, patterns, and outcomes of NTSCI in a tertiary care center. Methods: We have reviewed all adult patients who had a NTSCI and were surgically treated with a minimum follow-up of 12 months postoperatively. Demographic and clinical data were collected. Preoperative and postoperative American Spinal Injury Association (ASIA) impairment scales and past follow-up outcomes were assessed. Results: Of 164 patients, 95 (58%) had full recovery and reached ASIA E score at their last follow-up while 69 (42%) were not able to achieve full recovery till ASIA E score. Urinary incontinence and/or bowel incontinence on admission, degenerative pathologies, and thoracic injury level were all notable indicators of limited ASIA score improvement at the last follow-up. Conclusions: Surgically treated NTSCI could result in good neurological recovery with a low complication rate.
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