222 research outputs found

    A Novel Multiscale Modelling Approach for Evaluation of the ASR in Concrete Structures

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    This paper presents a new multiscale approach for evaluation of the volume change in concrete structures due to the alkali-silica reaction (ASR). A practical step by step approach that can be applied to the real structures is developed based on combined experimental and numerical assessment by considering the most influential ASR parameters at different scales. In the first step, the ASR expansion is measured using accelerated concrete cylinder test (ACCT) for different concrete mixtures covering different variables of important factors such as mix design (e.g., w/cm, fly ash type and replacement percentages), aggregate reactivity, alkali loadings, temperature, and relative humidity etc. All measured expansion data are then modelled using artificial neural network (ANN) modeling approach in the second step. In the third step, finite element (FE) model is utilized at different scales to analyze the real structures and representative volume element (RVE) taking into account the ASR gel expansion and structural boundary conditions. Finally, the effects of the structural constraints are taken into account by introducing correction factors to the predicted free expansion (i.e. no constraints) of the RVE by ANN model. It was found that a combined effect of both internal gel pressure and structural constraints determines the net volume expansion in a concrete structure. In order to show the applicability of the proposed approach, the model is employed for evaluation of the ASR-induced net volume expansion at different locations of a dam structure under realistic in-service conditions. The microstructural study was also done by using X-ray CT that can be used to estimate the ASR progress in concrete structure and validate / support the FEM based predictions

    SciTS: A Benchmark for Time-Series Databases in Scientific Experiments and Industrial Internet of Things

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    Time-series data has an increasingly growing usage in Industrial Internet of Things (IIoT) and large-scale scientific experiments. Managing time-series data needs a storage engine that can keep up with their constantly growing volumes while providing an acceptable query latency. While traditional ACID databases favor consistency over performance, many time-series databases with novel storage engines have been developed to provide better ingestion performance and lower query latency. To understand how the unique design of a time-series database affects its performance, we design SciTS, a highly extensible and parameterizable benchmark for time-series data. The benchmark studies the data ingestion capabilities of time-series databases especially as they grow larger in size. It also studies the latencies of 5 practical queries from the scientific experiments use case. We use SciTS to evaluate the performance of 4 databases of 4 distinct storage engines: ClickHouse, InfluxDB, TimescaleDB, and PostgreSQL

    L’impact de la digitalisation sur la performance de l’administration fiscale marocaine

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    Digitalization is a hot topic that has affected all sectors and organizations, including the Moroccan tax administration, which has taken it seriously in recent years. In this study, we seek to analyze and evaluate the impact of digital transformation on the performance of the Directorate General of Taxes (DGI) and its effectiveness as a strategic administration representing the sovereignty of the State. Thus we attempt to answer the question of how and to what extent the digital transformation carried out by the DGI has improved its performance. In order to provide relevant answers to this question, we first presented the general context in which the DGI embarked on the dematerialization of tax procedures and processes. Secondly, we set out the process of digital transformation within the DGI, presenting the main changes introduced in chronological order. Finally, we highlighted the impact of this digitalization on the performance of the DGI, based on a literature review and an exploratory study spread over the period from 2011 to 2021, using activity reports and other official documents of the DGI. The results showed that digitalization has made it possible to improve the control of tax management, increase revenues and enhance tax potential, broaden the tax base through the identification of new taxpayers, combat fraud and tax evasion, and establish a relationship of trust with the taxpayer through the simplification and transparency of electronic procedures.     Keywords: digitalization, tax administration, tax potential, performance, taxpayers                                             JEL Classification: E62, H21, K34Paper type: Theoretical ResearchLa digitalisation est un sujet d'actualité qui a touché tous les secteurs et toutes les organisations, y compris l'administration fiscale marocaine, qui a pris ce chantier au sérieux ces dernières années. Dans cette étude, nous cherchons à analyser et évaluer l'impact de la transformation numérique sur la performance de la Direction Générale des Impôts (DGI) et son efficacité en tant qu'administration stratégique représentant la souveraineté de l’État. Ainsi nous tentons de répondre à la problématique de comment et dans quelle mesure la transformation numérique menée par la DGI a amélioré sa performance ? Pour apporter des éléments de réponses pertinents à cette problématique, nous avons présenté dans un premier temps, le contexte général dans lequel la DGI s'est lancée dans la dématérialisation des procédures et démarches fiscales. Dans un deuxième temps, nous avons exposé le processus de la transformation numérique au sein de la DGI, en présentant de manière chronologique les principaux changements introduits. Enfin, nous avons mis en exergue l'impact de cette digitalisation sur la performance de la DGI, en nous basant sur une analyse documentaire et une étude exploratoire étalée sur la période de 2011 à 2021, à partir des rapports d’activité et d'autres documents officiels de la DGI.                                                                                                              Les résultats ont montré que la digitalisation a permis d'améliorer la maîtrise de la gestion fiscale, l’augmentation des recettes et la valorisation du potentiel fiscal, l'élargissement de l'assiette fiscale à travers l'identification de nouveaux contribuables, la lutte contre la fraude et l'évasion fiscale, ainsi que l'instauration d'une relation de confiance avec le contribuable grâce à la simplification et la transparence des procédures électroniques.     Mots clés : digitalisation, administration fiscale, potentiel fiscal, performance, contribuables             Classification JEL : E62, H21, K34Type de l’article : Article théoriqu

    Simultaneous Coating of Electrospun Nanofibers with Bioactive Molecules for Stem Cell Osteogenesis In Vitro

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    Objective: Mesenchymal stem cells (MSCs) are widely recognized as a promising cell type for therapeutic applicationsdue to their ability to secrete and regenerate bioactive molecules. For effective bone healing, it is crucial to select ascaffold that can support, induce, and restore biological function. Evaluating the scaffold should involve assessing MSCsurvival, proliferation, and differentiation. The principal aim of this investigation was to formulate composite nanofibrousscaffolds apt for applications in bone tissue engineering.Materials and Methods: In this experimental study, nanofibrous scaffolds were fabricated using Poly-L-lactic acid(PLLA) polymer. The PLLA fibers’ surface was modified by integrating collagen and hydroxyapatite (HA) nanoparticles.Results: The findings demonstrated that the collagen- and nanohydroxyapatite-modified electrospun PLLA scaffoldpositively influenced the attachment, growth, and osteogenic differentiation of MSCs.Conclusion: Coating the nanofiber scaffold with collagen and nanoparticle HA significantly enhanced the osteogenicdifferentiation of MSCs on electrospun PLLA scaffolds

    Prevalence of low back pain and its related factors among pre-hospital emergency personnel in Iran

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    Objective: Low back pain is one of the most important job injuries among emergency medical personnel. This study was carried out to investigate the prevalence of low back pain as well as its physical, mental and managerial predisposing factors among emergency medical personnel in Iran. Methods: In this analytical cross-sectional study we recruited 298 pre-hospital emergency medical personnel based on census sampling. Data were gathered using Nordic and a research-made questionnaire related to physical, mental and managerial back pain factors. Data were analyzed using SPSS version 20. Descriptive and analytical tests including chi-square test were used appropriately. P value less than 0.05 was considered as the level of significance. Results: Findings showed that 46.3% of pre- hospital emergency technicians had a history of low back pain with different intensities. We observed a significant relationship between age, work experience, occupational-physical factors with low back pain (P > 0.001). However, there was no significant relationship between occupational-managerial factors and mental-occupational factors with low back pain (P > 0.05). Conclusion: Results show that the prevalence of back pain among emergency medical personnel is high. Identifying the factors associated with back pain can help the managers as well as the personnel to control the problem of back pain and increase employees’ productivity

    Research Article Bacteraemia in Intensive Care Unit: Clinical, Bacteriological

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    Objectives. We conducted a one-year observational study from December 2012 to November 2013 to describe the epidemiology of bacteraemia in intensive care units (ICU) of Mohammed V Military Teaching Hospital of Rabat (Morocco). Methods. The study consisted of monitoring all blood cultures coming from intensive care units and studying the bacteriological profile of positive blood cultures as well as their clinical significance. Results. During this period, a total of 46 episodes of bacteraemia occurred, which corresponds to a rate of 15,4/1000 patients. The rate of nosocomial infections was 97% versus 3% for community infections. The most common source of bacteraemia was the lungs in 33%, but no source was identified in 52% of the episodes. Gram negative organisms were isolated in 83,6% of the cases with Acinetobacter baumannii being the most frequent. Antibiotic resistance was very high with 42,5% of extended-spectrum beta-lactamases (ESBLs) in Enterobacteriaceae and 100% of carbapenemase in Acinetobacter baumannii. The antibiotherapy introduced in the first 24 hours was adequate in 72% of the cases. Conclusions. Bloodstream infections in ICU occur most often in patients over 55 years, with hypertension and diabetes. The bacteria involved are mainly Gram negative bacteria multiresistant to antibiotics. Early administration of antibiotics significantly reduces patients mortality

    0-6656-01: Further Validation of Alkali-Silica Reaction (ASR) Testing and Approach for Formulating ASR Resistant Mix

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    0-6656-01Alkali-silica reaction (ASR) is recognized as a major concern for the Texas Department of Transportation (TxDOT). In the previous project 0-6656, a volumetric change measuring device (VCMD)\u2013based aggregate chemical method was validated as a rapid (within 5 days) and reliable method to determine aggregate reactivity in terms of measuring composite activation parameter (CAP) and measure aggregate threshold alkalinity (THA). A new accelerated concrete cylinder testing (ACCT) was developed in that project as a potential concrete ASR test

    Global, regional, and national burden of chronic kidney disease, 1990–2017 : a systematic analysis for the Global Burden of Disease Study 2017

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    Background Health system planning requires careful assessment of chronic kidney disease (CKD) epidemiology, but data for morbidity and mortality of this disease are scarce or non-existent in many countries. We estimated the global, regional, and national burden of CKD, as well as the burden of cardiovascular disease and gout attributable to impaired kidney function, for the Global Burden of Diseases, Injuries, and Risk Factors Study 2017. We use the term CKD to refer to the morbidity and mortality that can be directly attributed to all stages of CKD, and we use the term impaired kidney function to refer to the additional risk of CKD from cardiovascular disease and gout. Methods The main data sources we used were published literature, vital registration systems, end-stage kidney disease registries, and household surveys. Estimates of CKD burden were produced using a Cause of Death Ensemble model and a Bayesian meta-regression analytical tool, and included incidence, prevalence, years lived with disability, mortality, years of life lost, and disability-adjusted life-years (DALYs). A comparative risk assessment approach was used to estimate the proportion of cardiovascular diseases and gout burden attributable to impaired kidney function. Findings Globally, in 2017, 1·2 million (95% uncertainty interval [UI] 1·2 to 1·3) people died from CKD. The global all-age mortality rate from CKD increased 41·5% (95% UI 35·2 to 46·5) between 1990 and 2017, although there was no significant change in the age-standardised mortality rate (2·8%, −1·5 to 6·3). In 2017, 697·5 million (95% UI 649·2 to 752·0) cases of all-stage CKD were recorded, for a global prevalence of 9·1% (8·5 to 9·8). The global all-age prevalence of CKD increased 29·3% (95% UI 26·4 to 32·6) since 1990, whereas the age-standardised prevalence remained stable (1·2%, −1·1 to 3·5). CKD resulted in 35·8 million (95% UI 33·7 to 38·0) DALYs in 2017, with diabetic nephropathy accounting for almost a third of DALYs. Most of the burden of CKD was concentrated in the three lowest quintiles of Socio-demographic Index (SDI). In several regions, particularly Oceania, sub-Saharan Africa, and Latin America, the burden of CKD was much higher than expected for the level of development, whereas the disease burden in western, eastern, and central sub-Saharan Africa, east Asia, south Asia, central and eastern Europe, Australasia, and western Europe was lower than expected. 1·4 million (95% UI 1·2 to 1·6) cardiovascular disease-related deaths and 25·3 million (22·2 to 28·9) cardiovascular disease DALYs were attributable to impaired kidney function. Interpretation Kidney disease has a major effect on global health, both as a direct cause of global morbidity and mortality and as an important risk factor for cardiovascular disease. CKD is largely preventable and treatable and deserves greater attention in global health policy decision making, particularly in locations with low and middle SDI

    Global, regional, and national burden of other musculoskeletal disorders, 1990–2020, and projections to 2050: a systematic analysis of the Global Burden of Disease Study 2021

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    Background Musculoskeletal disorders include more than 150 different conditions affecting joints, muscles, bones, ligaments, tendons, and the spine. To capture all health loss from death and disability due to musculoskeletal disorders, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) includes a residual musculoskeletal category for conditions other than osteoarthritis, rheumatoid arthritis, gout, low back pain, and neck pain. This category is called other musculoskeletal disorders and includes, for example, systemic lupus erythematosus and spondylopathies. We provide updated estimates of the prevalence, mortality, and disability attributable to other musculoskeletal disorders and forecasted prevalence to 2050. Methods Prevalence of other musculoskeletal disorders was estimated in 204 countries and territories from 1990 to 2020 using data from 68 sources across 23 countries from which subtraction of cases of rheumatoid arthritis, osteoarthritis, low back pain, neck pain, and gout from the total number of cases of musculoskeletal disorders was possible. Data were analysed with Bayesian meta-regression models to estimate prevalence by year, age, sex, and location. Years lived with disability (YLDs) were estimated from prevalence and disability weights. Mortality attributed to other musculoskeletal disorders was estimated using vital registration data. Prevalence was forecast to 2050 by regressing prevalence estimates from 1990 to 2020 with Socio-demographic Index as a predictor, then multiplying by population forecasts. Findings Globally, 494 million (95% uncertainty interval 431–564) people had other musculoskeletal disorders in 2020, an increase of 123·4% (116·9–129·3) in total cases from 221 million (192–253) in 1990. Cases of other musculoskeletal disorders are projected to increase by 115% (107–124) from 2020 to 2050, to an estimated 1060 million (95% UI 964–1170) prevalent cases in 2050; most regions were projected to have at least a 50% increase in cases between 2020 and 2050. The global age-standardised prevalence of other musculoskeletal disorders was 47·4% (44·9–49·4) higher in females than in males and increased with age to a peak at 65–69 years in male and female sexes. In 2020, other musculoskeletal disorders was the sixth ranked cause of YLDs globally (42·7 million [29·4–60·0]) and was associated with 83 100 deaths (73 600–91 600). Interpretation Other musculoskeletal disorders were responsible for a large number of global YLDs in 2020. Until individual conditions and risk factors are more explicitly quantified, policy responses to this burden remain a challenge. Temporal trends and geographical differences in estimates of non-fatal disease burden should not be overinterpreted as they are based on sparse, low-quality data.publishedVersio

    Genomic characterization of SARS-CoV-2 in Egypt: insights into spike protein thermodynamic stability

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    The overall pattern of the SARS-CoV-2 pandemic so far has been a series of waves; surges in new cases followed by declines. The appearance of novel mutations and variants underlie the rises in infections, making surveillance of SARS-CoV-2 mutations and prediction of variant evolution of utmost importance. In this study, we sequenced 320 SARS-CoV-2 viral genomes isolated from patients from the outpatient COVID-19 clinic in the Children’s Cancer Hospital Egypt 57357 (CCHE 57357) and the Egypt Center for Research and Regenerative Medicine (ECRRM). The samples were collected between March and December 2021, covering the third and fourth waves of the pandemic. The third wave was found to be dominated by Nextclade 20D in our samples, with a small number of alpha variants. The delta variant was found to dominate the fourth wave samples, with the appearance of omicron variants late in 2021. Phylogenetic analysis reveals that the omicron variants are closest genetically to early pandemic variants. Mutation analysis shows SNPs, stop codon mutation gain, and deletion/insertion mutations, with distinct patterns of mutations governed by Nextclade or WHO variant. Finally, we observed a large number of highly correlated mutations, and some negatively correlated mutations, and identified a general inclination toward mutations that lead to enhanced thermodynamic stability of the spike protein. Overall, this study contributes genetic and phylogenetic data, as well as provides insights into SARS-CoV-2 viral evolution that may eventually help in the prediction of evolving mutations for better vaccine development and drug targets
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