Extracorporeal shock wave lithotripsy (ESWL) versus flexible ureteroscopy (F-URS) for management of renal stone burden less than 2 cm in children: A randomized comparative study

Objective: To compare the outcome of flexible ureteroscopy (F-URS) versus extracorporeal shock wave lithotripsy (ESWL) for the management of renal stone burden less than 2 cm in children.Patients and methods: A randomized comparative study was conducted at our hospital between December 2013 and May 2015. Seventy two children with renal stone burden less than 2 cm were assessed for eligibility. Our primary outcome is to assess the stone free rate after the first session. The secondary goal is to assess the operative outcome and the associated postoperative complications.Results: Finally, 57 children were completed the treatment and follow up; 27 patients in F-URS group and 30 patients in ESWL group. Patient’s demographics and stone characteristics were comparable between both groups. F-URS group was associated with significantly longer operative time and hospital stay versus ESWL group. Overall complications occurred in 29.6% and 33.3% in F-URS groups and ESWL group, respectively (p value = 0.1) and most of them were of minor degree. F-URS was associated with significantly higher stone free rate after the first session which reached 81.4% versus 53.3% for ESWL group (p value = 0.00). The overall success was 92.5% and 90% in F-URS and ESWL group, respectively (p value = 0.5).Conclusion: Stone free rate after one session of F-URS is higher than ESWL with comparable rates of complications. F-URS could be offered to children who are less likely to respond completely after ESWL monotherapy.Keywords: Pediatric urolithiasis; Minimal invasive stone management; Flexible URS; ESW

Impact of occult hepatitis B virus infection on antiviral therapy in chronic hepatitis C patients

Background: Occult HBV infection (OBI) can be defined by the presence of HBV-DNA in the serum of patients who are negative for HBsAg. The presence of OBI has been associated with a poor therapeutic response to alpha IFN in many, but not in all studies.Objective: The aim of our study was to assess the prevalence of OBI in the serum of Egyptian patients with CHC, and to evaluate its impact on the response to treatment with a combination of Peg-IFNa and RBV.Materials and methods: Fifty chronic HCV infected patients who were treated with Peg-IFNa once a week in combination with RBV for 48 weeks were included in this study. Patients were divided into two groups, group I which included 25 patients who achieved SVR and group II that included 25 patients who failed to achieve SVR (Non-SVR). Both patient groups were subjected to detailed questionnaire, clinical examination, routine laboratory investigations and virological studies.Results: No statistical significant difference was found in sex distribution regarding SVR and Non-SVR. The frequency of patients with low viral load has a statistically significant association.KEYWORDS: Chronic hepatitis C; Occult HBV infection; Sustained virological respons

Financial market index prediction using machine learning

The present work aims to tackle the crucial objective of forecasting values for a range of financial market indices in order to maximize income while minimizing potential losses. This study utilizes a comparative analysis approach to examine the performance of artificial neural networks (ANNs) and decision tree models in predicting stock market movements in Saudi Arabia (KSA). The analysis is conducted using a daily database. The predictive models included in this study are constructed using historical stock market data, which encompasses the time period from January 1, 2013, to October 4, 2023. The primary objective of these models is to generate accurate projections specifically for the Tadawul Daily Index. The main objective of this study is to evaluate and contrast the effectiveness of artificial neural network (ANN) and decision tree models in predicting the performance of the stock market in Saudi Arabia. The analysis demonstrates that the decision tree model has a somewhat lower predictive capability when compared to the artificial neural network (ANN) model. The present study utilizes statistical metrics, namely root-mean-squared error (RMSE) and mean absolute error (MAE), to assess and quantify the accuracy of predictions. Moreover, a thorough examination is undertaken, encompassing a range of relevant statistical indicators, and visually representing the data series using graphical means. The utilization of a diverse methodology serves to augment knowledge and facilitate a comprehensive grasp of the intrinsic daily patterns observed in the Tadawul Daily Index. The objective is to enhance the understanding and examination of the complexities of the stock market, so empowering investors and financial analysts to make educated choices that match with their strategic goals and risk management methods. The studys findings provide significant contributions to the field of financial market prediction, specifically in the Kingdom of Saudi Arabia

A Study of The Saudi Stock Market Using Some Statistical Models

The objective of this paper is to estimate the diversification effects/benefits of an investment in a portfolio consisting of the South African Industrial (J520) and the Financial (J580) Indices using the Generalised Pareto Distributions (GPDs) with an extreme value Gumbel copula. The GPD is used as the marginal distribution to both assets to better characterize the extreme risk of returns in both Indices tails. The extreme value Gumbel copula captures the dependence structure (co-movement) of the financial assets in the portfolio. The Akaike information criterion (AIC) and Bayesian information criterion (BIC) goodness of fit tests and the scatterplots indicate that the upper tail of the gains (the larger gains) risk and the losses tail (the larger losses) are best captured using the extreme value Gumbel copula. Monte Carlo simulation of an equally weighted portfolio of the two Indices is used to estimate the portfolio risk. The univariate marginal risks and the portfolio risks are used to calculate the diversification effects/benefits. The results show that there are benefits in diversification since the riskiness of the portfolio is less than the sum of the risk of the two financial assets. This implies that VaR, although not additive theoretically, is sub-additive in this practical situation. This property of sub-additivity represents the benefits of diversification for a portfolio. The implication is that investors investing in individual risky assets can benefit from constructing such a portfolio to reduce extreme risk. Due to high dependence and contagion between developed markets/Global markets, this is useful information for local and international investors seeking a portfolio which includes developing countries market Indices, such as South African assets, which are less correlated with other Global markets, thereby reducing the risk of contagion

On q-Generalized Extreme Values under Power Normalization with Properties, Estimation Methods and Applications to Covid-19 Data

This paper introduces the q-analogues of the generalized extreme value distribution and its discrete counterpart under power normalization. The inclusion of the parameter q enhances modeling flexibility. The continuous extended model can produce various types of hazard rate functions, with supports that can be finite, infinite, or bounded above or below. Additionally, these new models can effectively handle skewed data, particularly those with highly extreme observations. Statistical properties of the proposed continuous distribution are presented, and the model parameters are estimated using various approaches. A simulation study evaluates the performance of the estimators across different sample sizes. Finally, three distinct real datasets are analyzed to demonstrate the versatility of the proposed model

Endozoochory by goats of two invasive weeds with contrasted propagule traits

Invasive plants have very important ecological and socioeconomic impacts. Producing and dispersing many viable seeds are key plant functional traits for invaders. Ungulate grazing plays an important role in the endozoochorous seed dispersal within grasslands and rangelands. Grazing can be applied as a practical and economical control method for plant invasions. We analyzed the effects of seed passage through the goat digestive system on the germination and viability for Sorghum halepense and Malva parviflora, common invasive species with contrasted propagules and seed traits. Both studied species produced seeds able to survive, in a small percentages (c. 0.80-1.70%), after being eaten by goats. Most of the seeds (c. 40-55%) of both species were retrieved between 24-48 h after ingestion. Goat passage provoked a decrease (> 60%) in the germination percentage and seed viability of S. halepense that was higher with longer gut retention times. In M. parviflora, the goat gut passage did not break its primary physical dormancy, since no retrieved seed germinated with similar viability as the uneaten seeds (c. 90%). In view of our results, goat grazing can be applied as a useful method to control S. halepense and M. parviflora invasions. Goats should be kept in corrals for at least 4 days after grazing to prevent transferring viable seeds to uninfected areas.Deanship of Scientific Research King Khalid University R.G.P.1/210/4

Characterization and classification of the microporosity in the unconventional carbonate reservoirs: A case study from Hanifa Formation, Jafurah Basin, Saudi Arabia

Formation porosity is a key factor that exerts substantial control upon reserve estimates, and ultimately may affect the development viability of unconventional resources. Microporosity studies have largely focused on siliciclastic mudstones, with limited examples that assess porosity type and distribution in organic-rich calcareous mudstone successions. In this work, a comprehensive porosity characterization study was performed on the organic-rich carbonate-dominated Hanifa Formation of the Jafurah Basin, which is the largest unconventional basin in Saudi Arabia. An extensive experimental program, involving petrographical description, SEM analysis, mineralogical analysis using XRD and QEMSCAN, and geochemistry analysis was employed in order to characterize the samples and analyze the geological origins of the microporosity. The main constituent minerals in this study are calcite (87 wt%) and anhydrite (9 wt%), as well as 85%. Fundamentally, the findings of this study demonstrate that the Hanifa Formation in the Jafurah Basin has the potential for gas exploration and recovery

Productivity and Thermal Performance Enhancements of Hollow Fiber Water Gap Membrane Distillation Modules Using Helical Fiber Configuration: 3D Computational Fluid Dynamics Modeling

Although hollow fiber water gap membrane distillation (HF-WGMD) units offer certain advantages over other MD desalination systems, they still require enhancements in terms of distillate flux and productivity. Therefore, this work proposes a novel configuration by incorporating the helical turns of HF membranes within the water gap channel of the HF-WGMD modules. A fully coupled 3D CFD model is developed and validated to simulate the multifaceted energy conservations and diffusion mechanisms that are inherent to the transport phenomena in the proposed HF-WGMD module. Single and double helical HF membrane designs with different numbers of turns are compared to the reference modules of single and double straight HF membrane designs under various operational conditions. At a feed temperature of 70 °C, a noteworthy 11.4% enhancement in the distillate flux is observed when employing 20 helical turns, compared to the single straight HF membrane module. Furthermore, the specific productivity revealed a maximum enhancement of 46.2% when using 50 helical turns. The thermal performance of the proposed HF-WGMD module shows higher energy savings of up to 35% in specific thermal energy consumption for a one-stage module. Using three stages of single helical modules can increase the gain output ratio from 0.17 for the single stage to 0.37, which represents an increase of 117.6%. These findings indicate the high potential of the proposed approach in advancing the performance of HF-WGMD systems