260 research outputs found
Within the gated: before and after the Egyptian revolution
Modified part Neoliberal dream of segregation: rethinking gated communities in greater Cairo, a case study: AL-Rehab City gated communit
Work-life balance approaches among educated working married mothers in Egypt
This research will explore the ways in which the work–life balance (WLB) approaches can assist Egyptian educated working married mothers in balancing their lives successfully between their work and families. These mothers are navigating their way through several challenges. The major challenge is the ability to pursue a career while also managing family responsibilities. This research will focus on two streams, the working conditions and the surrounding environment of interviewed women. The research design of the study was based on qualitative methods. A purposeful sample of educated Egyptian working married mothers was chosen from women working in a variety of private, government and nonprofit organizations. The data collection method will be based on ten in-depth interviews. The study shows that the major challenge these women face is be related to time deprivation. The overall conclusion of this research indicates that a supportive environment at both home and work is crucial for these women to combine their different roles
Review of crash prediction models and their applicability in black spot identification to improve road safety
Objective: This study aims to review of the development of crash prediction models, and their applications to analyse and identify black spots to improve road safety.
Methods: Several modelling techniques have been reviewed in this study including, multiple linear regression, Poisson distribution, negative binomial, random effect technique, and multiple logistic regression models to identify their suitability to develop the crash prediction models. The studies related to the identification of black spots were also reviewed based on the type of crash data used in the identification process.
Result: The reviewed documents highlight the shortcomings within the traditional crash prediction models (CPMs), as well as the demonstrated the flexibilities and effectiveness of the latest methods. Most suitable models can now be developed to represent the actual scenarios from several modelling techniques, where they provide a realistic and accurate prediction of crash frequency, for example, to determine if the location had a traffic safety problem compared to other locations with similar conditions and to identify the suitable measures to reduce crashes.
Application/Improvements: The models identified in this research are already being used but the modelling approaches can be further modified to include the latest technical application on roads, available post-crash management system or safety culture which are commonly related road safety outcomes
Proučavanje mehanizma laserske litotripsije optičkim tehnikama
Phenomena relevant to fragmentation of gallbladder stone during a pulsed laser action were studied. Real conditions have been simulated. A stone was immersed in distilled water and laser energy was delivered to its surface by an optical fiber. Two different cases were studied: when the tip of the fiber was in contact with the stone and when it was at a distance from it. Using ultra-fast shadowgraphy and interferometry, mechanism of destruction of a stone due to laser-based lithotripsy was studied.Proučavamo pojave razbijanja žućnog kamena tijekom djelovanja laserskog impulsa. Oponašali smo stvarne uvjete kamena stavljanjem u destiliranu vodu, a lasersku energiju prenosili smo na njegovu površinu optičkom niti. Razmatrali smo dva slučaja: vrh niti u dodiru s kamenom i na nekoj udaljenosti od kamena. Primijenili smo metodu fotografije sjena i interferometriju za proučavanje mehanizma razbijanja kamena laserskom litotripsijom
Optimisation of road safety treatment strategies through crash modification factors and simulation
Road safety has become an intensively studied topic with an overarching aim of better understanding why road crashes occur and thus to reduce both frequency and severity. If it is known why road crashes occur, agencies should be able to better apply more effective and efficient road safety improvement strategies. The aim of the traffic engineer is to design and provide a safe travel environment to the road user. While road crashes cannot be completely prevented, a sound understanding of the causative factors helps to minimise crash rate. Crash occurrences can be viewed as a result of the interaction of numerous variables including road geometry, vehicle condition, and operational conditions such as speed and traffic volume.
The main objective of this research was to evaluate traffic and geometric road features and their influences on the safety performance of road intersections, roundabouts, and road segments by estimating suitable crash modification factors (CMFs). To accomplish the study objective, crash prediction models (CPMs) were developed using a generalised linear model (GLM) technique, i.e. Poisson or negative binomial (NB) distribution. The regional area of Toowoomba City, Australia was adopted as the case study. Traffic, geometric, and crash data on 106 road intersections for the years 2008-2015, as well as 49 roundabouts and 84 roadway segments for years the 2010-2015 were used for crash modelling and evaluation. The NB distribution was adopted in preference to Poisson distribution as the data showed over-dispersion. Several goodness-of-fit (GOF) tests were performed on the developed models to identify the better-fitting models. These models were then validated using both the estimation and validation datasets.
An accurate identification of hazardous road locations (HRLs) prevents wasted resources that may result if possible improvements at such locations are identified with less accuracy. The Empirical-Bayes (EB) approach was employed to identify the HRLs in the study area. This approach was adopted to provide more accurate safety estimation by accounting for the regression-to-the-mean bias usually associated with the road crash data. The HRLs were then ranked based on their potential for safety improvement (PSI) value, which is the difference between the expected and predicted road crashes at each location. The top 10 poorly performing locations for each of theroad intersections, roundabouts, and road segments were identified for further investigation.
The CMFs identify any change in the safety performance resulting from implementing a particular treatment. In this study, CMFs were used to estimate the effect of the various proposed safety treatments at identified HRLs. The cross-sectional method (regression approach) was applied to estimate CMFs for individual safety treatment. This method has been considered recently and has not been extensively applied, however, it can be considered as a viable alternative method to estimate the CMFs in cases where observational before-and-after studies are not practical due to data restrictions.
In order to estimate the variation in the values of CMF with different sites characteristics, the crash modification functions (CMFunctions) were developed. Using CMFunctions, the safety effects of various traffic and geometric elements of different road facilities (i.e., intersections, roundabouts, and roadway segments) were investigated. The study also notes that while there has been substantial research in the broad area, very few studies have been undertaken to estimate CMFs for the combined effect of multiple safety treatments. However, the four most suitable techniques for estimating combined CMFs were reviewed and applied together to propose effective safety measures for the HRLs. Since there were variations in the estimation of combined CMFs using the four techniques, the average values were adopted as the best approach to estimate the effect of combined treatments. The results demonstrated that multiple treatments have higher safety effects (i.e., lower CMF) than single treatments. The results also indicated that the effect of treatments on road safety does not depend on the number of treatments that have been applied but rather depend on environment.
The traffic simulation software PTV VISSIM 9.0 was employed to assess the traffic operational performance before and after safety treatment implementation. The top 10 HRLs for each of the road facilities were simulated and evaluated under different scenarios in terms of level of service (LOS), traffic delay, travel time, and average speed. The results showed that there is no significant degradation of traffic operations expected at treated locations.
Finally, a benefit analysis was conducted to estimate the savings during the 10 years after applying the proposed treatments. The crash reduction factors and crash costs were utilised to estimate the crash cost reduction that was associated with single and combined treatments. Such estimation can support road authorities and practitioners to select the final treatment plans for the identified HRLs by undertaking benefit-cost analysis to assist the decision-making process.
Contributions of this research can be summarised as: (i) to develop CPMs for different types of road facilities, (ii) to develop CMFunctions to estimate the variation in the values of CMF with different sites characteristics, (iii) to propose a methodology to identify the most appropriate safety treatments (single and multiple treatments) using CMFs, costing and simulation packages. The research has also identified some important aspects for future research to extend the present work
Proučavanje mehanizma laserske litotripsije optičkim tehnikama
Phenomena relevant to fragmentation of gallbladder stone during a pulsed laser action were studied. Real conditions have been simulated. A stone was immersed in distilled water and laser energy was delivered to its surface by an optical fiber. Two different cases were studied: when the tip of the fiber was in contact with the stone and when it was at a distance from it. Using ultra-fast shadowgraphy and interferometry, mechanism of destruction of a stone due to laser-based lithotripsy was studied.Proučavamo pojave razbijanja žućnog kamena tijekom djelovanja laserskog impulsa. Oponašali smo stvarne uvjete kamena stavljanjem u destiliranu vodu, a lasersku energiju prenosili smo na njegovu površinu optičkom niti. Razmatrali smo dva slučaja: vrh niti u dodiru s kamenom i na nekoj udaljenosti od kamena. Primijenili smo metodu fotografije sjena i interferometriju za proučavanje mehanizma razbijanja kamena laserskom litotripsijom
Developing crash modification factors for roundabouts using a cross-sectional method
The objective of the current study was to evaluate traffic and geometric features and their influences on the safety performance of roundabouts by developing suitable crash modification factors (CMFs). The cross-sectional method can be applied as an alternative method to estimate the CMFs when before-and-after studies are impractical to apply, e.g., lack of data from the period after implementing treatments. To accomplish the study objective, CMFs were derived from generalised linear models (GLMs), i.e., negative binomial (NB) regression, using data collected on regional roundabouts in Toowoomba City, Australia. Six years of crash data from 49 roundabouts included all recorded crashes as well as traffic and geometric features for the entire roundabouts. Several candidate models were developed using the GLMs. Five models were selected based on statistical significance, goodness-of-fit (GOF) measures, and cumulative residual (CURE) analysis. The results show that increasing the number of entry lanes, entry width, entry radius, traffic volume, circulatory roadway width, weaving width, and speed limit have positive effects on roundabout safety. On the other hand, increasing the number of legs, number of exit lanes, exit width, exit radius, weaving length, central island diameters, and presence of fixed object on a central island have negative effects on roundabout safety. The study shows that quantifying the risk factors can support road safety stakeholders to identify safety improvements at roundabouts more effectively and efficiently
RSRC1 loss-of-function variants cause mild to moderate autosomal recessive intellectual disability.
GNA11 brain somatic pathogenic variant in an individual with phacomatosis pigmentovascularis
Objective:
To describe the findings of histopathology and genotyping studies in affected brain tissue from
an individual with phacomatosis pigmentovascularis (PPV). /
Methods:
A retrospective chart review of a 2-year 10-month-old male with a clinical diagnosis of PPV
cesiomarmorata (or type V) was performed. Clinical features, brain imaging and histopathology
findings, and genotyping studies in his affected brain tissue are summarized. /
Results:
The proband had a clinically severe neurologic phenotype characterized by global developmental delay, generalized hypotonia, and recurrent episodes of cardiac asystole in the
setting of status epilepticus. A somatic pathogenic variant in GNA11 (c.547C>T, p.Arg183Cys)
was detected in his skin tissue but not in blood (previously published). He underwent an urgent
left posterior quadrantectomy for his life-threatening seizures. Histopathology of resected brain
tissue showed an increase in leptomeningeal melanocytes and abnormal vasculature, and the
exact pathogenic variant in GNA11 (c.547C>T, p.Arg183Cys), previously isolated from his skin
tissue but not blood, was detected in his resected brain tissue. /
Conclusions:
The finding of this variant in affected skin and brain tissue of our patient with PPV supports
a unifying genetic diagnosis of his neurocutaneous features
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