QarSUMO: A Parallel, Congestion-optimized Traffic Simulator

Traffic simulators are important tools for tasks such as urban planning and transportation management. Microscopic simulators allow per-vehicle movement simulation, but require longer simulation time. The simulation overhead is exacerbated when there is traffic congestion and most vehicles move slowly. This in particular hurts the productivity of emerging urban computing studies based on reinforcement learning, where traffic simulations are heavily and repeatedly used for designing policies to optimize traffic related tasks. In this paper, we develop QarSUMO, a parallel, congestion-optimized version of the popular SUMO open-source traffic simulator. QarSUMO performs high-level parallelization on top of SUMO, to utilize powerful multi-core servers and enables future extension to multi-node parallel simulation if necessary. The proposed design, while partly sacrificing speedup, makes QarSUMO compatible with future SUMO improvements. We further contribute such an improvement by modifying the SUMO simulation engine for congestion scenarios where the update computation of consecutive and slow-moving vehicles can be simplified. We evaluate QarSUMO with both real-world and synthetic road network and traffic data, and examine its execution time as well as simulation accuracy relative to the original, sequential SUMO

The Role of Ultrasound Muscle Parameters for Myosteatosis and Myofibrosis Measurement in Young, Older, and Obese Subjects

Objectives: The aim of the study was to compare quantitative and qualitativehigher echogenicity, a higher compressibi ultrasound parameters between healthy young adults and post-acute hospitalized older adults with and without physical disability, as well as between normal weight and overweight/obese persons. Design: Cross-sectional observational study. Setting and participants: A total of 120 individuals were recruited: 24 healthy young adults, 24 normal weight and 24 overweight/obese community-dwelling adults, and 48 post-acute hospitalized older adults with different degrees of functional autonomy. Methods: The rectus femoris cross-sectional area (CSA), subcutaneous adipose tissue (SCAT) thickness, echogenicity, strain elastography, and compressibility were measured with ultrasound echography. Results: Post-acute older adults with a good level of autonomy showed lity index and elastometry strain, and lower rectus femoris thickness and CSA as compared with young persons. Post-acute individuals with physical disability showed lower echogenicity and a greater stiffness compared with their still autonomous counterparts. Normal weight individuals showed lower stiffness as evaluated with elastometry and a lower SCAT thickness, as compared with individuals with age-matched overweight or obesity. From multiple regression analyses, using CSA as an independent variable, an inverse association with female sex and age was observed, explaining 16% and 51% of variance. Echogenicity was directly associated with age (34% of variance) and with the Barthel index (6% of variance). Elastometry showed association with age and body mass index (BMI), 30% and 16% of variance, respectively. Considering compressibility as a dependent variable, a direct association with age and an inverse association with BMI were observed, with 5% and 11% of variance respectively. Conclusions and implications: Muscle mass decreases with age and with physical disability. Echogenicity, which increases with age and disability level, seems to be associated with myofibrosis. Conversely, elastometry seems useful in the characterization of muscle quality in overweight or obese individuals and as a reliable indirect measure of myosteatosis

NMR and MRCP After Secretin Infusion in a Long-Term Comparison Study of Pancreogastro- vs. Pancreojejuno-Duodenopancreatectomy

Context After pylorus-preserving pancreaticoduodenectomy the anastomosis of pancreatic remnant may be done with the stomach (pancreogastric, PGA) or the jejunum (pancreojejunum, PJA). Recently, we have found that, in the long-term, PGA is associated with a more severe impairment of the residual pancreatic function. No data are available on the RNM ability to demonstrate an impairment of the residual pancreatic secretion or morphological changes after surgery. Methods Patients who 6 years ago entered a controlled short term comparison of PGA and PJA were studied by RNM and MRCP after secretin infusion (quantification of residual pancreatic volume, pancreatic duct diameter immediately proximal to the anastomosis, qualitative impairment of secretion), and tests of exocrine (fecal elastase-1, fecal fat balance) function. Two radiologists, blinded to the results of functional parameters, independently scored the residual pancreatic volume, duct diameter and secretin-stimulated secretion. Mean±SEM are shown. The Student’s t test was used. Results We studied 34 patients (16 PGA, 18 PJA; age 56.6±2.7 vs. 57.5±2.5 years; time from surgery 81±5 vs. 80±3 months). PGA was associated with a more severe impairment of steatorrhea than PJA (26.6±4.1 vs. 18.2±3.6 g/day; reference range: 0-7; P<0.01) and of fecal elastase-1 (70.2±25.5 vs. 121.4±6.7 µg/g; P<0.001). RNM showed in PGA a more marked dilatation of the pancreatic duct (diameter 4.63±0.91 vs. 2.50±0.18 mm, P<0.05) and non significant tendency to a smaller residual pancreas (26.3±3.0 vs. 35.9±4.1 mL; P=0.069). There is a power correlation between residual pancreas and steatorrhea. After secretin infusion, the secretion was consistently considered by two different radiologists to be more frequently impaired in PGA (42%) than in PJA (18%; P=0.05, Fisher test). Conclusion The pancreo-gastric anastomosis is associated, in the long run, with more severe morphological and functional impairment of exocrine function than the pancreo-jejunal one

Authoritative and Protective Insignia, Regalia and Symbols in Nubian Afro-Byzantine Rulers’ Iconography

The article is partly based on my doctoral research and results of my University of Pretoria (UP) project on Afro-Byzantine art.This article discusses the “authority and protection” insignia, regalia and symbols which are used in the Nubian Afro-Byzantine iconography of kings, eparchoi and other royals. They are discussed and analysed—through the study of the most important frescos in Nubian medieval churches—in terms of their position, function and meaning within the Byzantine and Afro-Byzantine context. The article reaches a number of conclusions referring to the religious, artistic, symbolic, political and institutional use and value of these representations of authority, protection and their connotations.http://www.tandfonline.com/toc/rech202019-05-25hj2019Humanities Educatio