FINITE ELEMENT METHODS FOR AXISYMMETRIC PDES AND DIVERGENCE FREE FINITE ELEMENT PAIRS ON PARTICULAR MESH REFINEMENTS

This dissertation discusses the following two main topics. 1) Finite element approximation for Partial Differential Equations (PDEs) defined on axisymmetric domains: We introduce the Darcy equations on axisymmetric domains and we show the stability of a low--order Raviart-Thomas element pair. We provide numerical experiments to support our theoretical results. Also, we introduce the Stokes equations on axisymmetric domains and show that the axisymmetric Stokes equations can fit within a commutative de Rham complex. 2) Connection between the grad-div stabilized and divergence-free Stokes finite element pairs and low--order divergence-free elements on particular mesh refinements: We introduce the most recent results that connect the grad-div stabilized Taylor--Hood (TH) finite element pair and divergence-free Scott--Vogelius (SV) finite element pairs, and we use these results to extend and generalize this connection to other Stokes finite element pairs. Finally, we provide numerical examples for low order divergence-free Stokes finite element pairs defined on particular mesh refinements. This research is focused on the numerical implementation aspects of these finite element pairs

Numerical Approximations for the Null Controllers of Structurally Damped Plate Dynamics

In this paper, we consider a structurally damped elastic equation under hinged boundary conditions. Fully-discrete numerical approximation schemes are generated for the null controllability of these parabolic-like PDEs. We mainly use finite element method (FEM) and finite difference method (FDM) approximations to show that the null controllers being approximated via FEM and FDM exhibit exactly the same asymptotics of the associated minimal energy function. For this, we appeal to the theory originally given by R. Triggiani [20] for construction of null controllers of ODE systems. These null controllers are also amenable to our numerical implementation in which we discuss the aspects of FEM and FDM numerical approximations and compare both methodologies. We justify our theoretical results with the numerical experiments given for both approximation schemes

Clinical Relevance of the Standardized Uptake Value (Suv) in Staging Breast Cancer with FDG-PET/CT

Purpose : FDG-PET/CT with standardized uptake value (SUV) estimation was applied to breast cancer patients for the purpose of preoperative evaluation of the extent of the disease. Methods : FDG-PET/CT was performed preoperatively in 71 patients with breast cancer, and the maximum standardized uptake value (SUVmax) of tumors, as well as combination of SUVmax and tumor marker CA 15-3 were investigated for a significant association with lymph node spread and distant metastasis. Results : Tumor SUVmax high (>3.1) was found to have a reliable predictive value for lymph node spread (sensitivity 82.9%, specificity 75%, P3.8)/CA 15-3-Elevated was found to be superior for the prediction of metastasis (sensitivity ; 75%, specificity ; 92.7%, P=0.0001). Moreover, linear regression analysis identified the best correlation was between SUVmax-High (>3.1) with lymph node spread {correlation coefficient (r^2)=0.580, P=0.0001}, and SUVmax-High (>3.8)/CA 15-3-Elevated with distant metastasis {correlation coefficient (r^2)=0.677, P<0.0001}. Conclusions : SUVmax is a reliable predictor of lymph node spread, and if combined with tumor marker assay (CA 15-3) labeled SUVmax-High/CA 15-3-Elevated is sufficient for the early detection of breast cancer metastasis. This outcome suggests that the FDG-PET/CT findings with SUV calculation could have a strong positive impact on breast cancer patients

Bioconversion of High Concentrations of Hydrogen Sulfide to Elemental Sulfur in Airlift Bioreactor

Several bioreactor systems are used for biological treatment of hydrogen sulfide. Among these, airlift bioreactors are promising for the bioconversion of hydrogen sulfide into elemental sulfur. The performance of airlift bioreactors is not adequately understood, particularly when directly fed with hydrogen sulfide gas. The objective of this paper is to investigate the performance of an airlift bioreactor fed with high concentrations of H2S with special emphasis on the effect of pH in combination with other factors such as H2S loading rate, oxygen availability, and sulfide accumulation. H2S inlet concentrations between 1,008 ppm and 31,215 ppm were applied and elimination capacities up to 113 g H2S m−3 h−1 were achieved in the airlift bioreactor under investigation at a pH range 6.5–8.5. Acidic pH values reduced the elimination capacity. Elemental sulfur recovery up to 95% was achieved under oxygen limited conditions (DO < 0.2 mg/L) and at higher pH values. The sulfur oxidizing bacteria in the bioreactor tolerated accumulated dissolved sulfide concentrations >500 mg/L at pH values 8.0–8.5, and near 100% removal efficiency was achieved. Overall, the resident microorganisms in the studied airlift bioreactor favored pH values in the alkaline range. The bioreactor performance in terms of elimination capacity and sulfur recovery was better at pH range 8–8.5

Surveillance of cirrhosis for hepatocellular carcinoma: a cost-utility analysis.

Using a decision-analytic model, we evaluated the effectiveness and cost-effectiveness of surveillance for hepatocellular carcinoma (HCC) in individuals with cirrhosis. Separate cohorts with cirrhosis due to alcoholic liver disease, hepatitis B and hepatitis C were simulated. Results were also combined to approximate a mixed aetiology population. Comparisons were made between a variety of surveillance algorithms using alpha-foetoprotein (AFP) assay and/or ultrasound at 6- and 12-monthly intervals. Parameter estimates were obtained from comprehensive literature reviews. Uncertainty was explored using one-way and probabilistic sensitivity analyses. In the mixed aetiology cohort, 6-monthly AFP+ultrasound was predicted to be the most effective strategy. The model estimates that, compared with no surveillance, this strategy may triple the number of people with operable tumours at diagnosis and almost halve the number of people who die from HCC. The cheapest strategy employed triage with annual AFP (incremental cost-effectiveness ratio (ICER): 20,700 pounds per quality-adjusted life-year (QALY) gained). At a willingness-to-pay threshold of 30,000 pounds per QALY the most cost-effective strategy used triage with 6-monthly AFP (ICER: 27,600 pounds per QALY gained). The addition of ultrasound to this strategy increased the ICER to 60,100 pounds per QALY gained. Surveillance appears most cost-effective in individuals with hepatitis B-related cirrhosis, potentially due to younger age at diagnosis of cirrhosis. Our results suggest that, in a UK NHS context, surveillance of individuals with cirrhosis for HCC should be considered effective and cost-effective. The economic efficiency of different surveillance strategies is predicted to vary markedly according to cirrhosis aetiology

The Alterity of the Image: the Distant Spectator and Films about the Syrian Revolution and War

Images of the Syrian crisis, circulating on the international film festival circuit as well as in mainstream and social media, help to construct narratives about those events, people and places. This article explores how three Syrian documentaries – Silvered Water: Syria Self-Portrait, The War Show and Little Gandhi – appeal to their distant spectators and how the international film festival circuit shapes their aesthetic form. While the use of citizen videos in news reporting has generated a sense of familiarity with the audio-visual style and iconography of Syrian conflict imagery, these films invite us to look at their footage in a different way, foregrounding an experience of cultural distance through an emphasis on the formal qualities of the image. By focusing on the aesthetic rather than merely evidentiary qualities of these documentaries, I draw out a particular kind of transnational cinematic encounter in which, to borrow John Berger’s words, ‘meaning is a response not only to the known, but to the unknown’. Drawing upon the work of Berger and Laura Marks, the article offers a new conceptualization of distant spectatorship in terms of the alterity of the image

Epidemiology of Chlamydia trachomatis in the Middle East and north Africa: a systematic review, meta-analysis, and meta-regression.

BACKGROUND: The epidemiology of Chlamydia trachomatis in the Middle East and north Africa is poorly understood. We aimed to provide a comprehensive epidemiological assessment of C trachomatis infection in the Middle East and north Africa. METHODS: We did a systematic review of C trachomatis infection as well as a meta-analysis and meta-regression of C trachomatis prevalence. We searched PubMed and Embase, as well as regional and national databases up to March 13, 2019, using broad search terms with no language or year restrictions. Any document or report including biological measures for C trachomatis prevalence or incidence was eligible for inclusion. We extracted all measures of current (genital or rectal), recent, and ever infection with C trachomatis. We estimated pooled average prevalence in different populations using random-effects meta-analysis. Factors associated with prevalence and sources of between-study heterogeneity were determined using meta-regression. FINDINGS: We identified a total of 1531 citations, of which 255 reports contributed to 552 C trachomatis prevalence measures from 20 countries. No incidence measures were identified. Pooled prevalence of current genital infection was 3·0% (95% CI 2·3-3·8) in general populations, 2·8% (1·0-5·2) in intermediate-risk populations, 13·2% (7·2-20·7) in female sex workers, 11·3% (9·0-13·7) in infertility clinic attendees, 12·4% (7·9-17·7) in women with miscarriage, 12·4% (9·4-15·7) in symptomatic women, and 17·4% (12·5-22·8) in symptomatic men. Pooled prevalence of current rectal infection was 7·7% (4·2-12·0) in men who have sex with men. Substantial between-study heterogeneity was found. Multivariable meta-regression explained 29·0% of variation. Population type was most strongly associated with prevalence. Additional associations were found with assay type, sample size, country, and sex, but not with sampling methodology or response rate (about 90% of studies used convenience sampling and >75% had unclear response rate). There was no evidence for temporal variation in prevalence between 1982 and 2018. INTERPRETATION: C trachomatis prevalence in the Middle East and north Africa is similar to other regions, but higher than expected given its sexually conservative norms. High prevalence in infertility clinic attendees and in women with miscarriage suggests a potential role for C trachomatis in poor reproductive health outcomes in this region. FUNDING: National Priorities Research Program from the Qatar National Research Fund (a member of Qatar Foundation)

Opportunities for Environmental Noise Mapping in Saudi Arabia: A Case of Traffic Noise Annoyance in an Urban Area in Jeddah City

As the traffic and other environmental noise generating activities are growing in The Kingdom of Saudi Arabia (KSA), adverse health and other impacts are expected to develop. The management of such problem involves many actions, of which noise mapping has been proven to be a helpful approach. The objective of the current study was to test the adequacy of the available data in KSA municipalities for generating urban noise maps and to verify the applicability of available environmental noise mapping and noise annoyance models for KSA. Therefore, noise maps were produced for Al-Fayha District in Jeddah City, KSA using commercially available noise mapping software and applying the French national computation method “NMPB” for traffic noise. Most of the data required for traffic noise prediction and annoyance analysis were available, either in the Municipality GIS department or in other governmental authorities. The predicted noise levels during the three time periods, i.e., daytime, evening, and nighttime, were found higher than the maximum recommended levels established in KSA environmental noise standards. Annoyance analysis revealed that high percentages of the District inhabitants were highly annoyed, depending on the type of planning zone and period of interest. These results reflect the urgent need to consider environmental noise reduction in KSA national plans. The accuracy of the predicted noise levels and the availability of most of the necessary data should encourage further studies on the use of noise mapping as part of noise reduction plans

Opportunities for Environmental Noise Mapping in Saudi Arabia: A Case of Traffic Noise Annoyance in an Urban Area in Jeddah City

As the traffic and other environmental noise generating activities are growing in The Kingdom of Saudi Arabia (KSA), adverse health and other impacts are expected to develop. The management of such problem involves many actions, of which noise mapping has been proven to be a helpful approach. The objective of the current study was to test the adequacy of the available data in KSA municipalities for generating urban noise maps and to verify the applicability of available environmental noise mapping and noise annoyance models for KSA. Therefore, noise maps were produced for Al-Fayha District in Jeddah City, KSA using commercially available noise mapping software and applying the French national computation method “NMPB” for traffic noise. Most of the data required for traffic noise prediction and annoyance analysis were available, either in the Municipality GIS department or in other governmental authorities. The predicted noise levels during the three time periods, i.e., daytime, evening, and nighttime, were found higher than the maximum recommended levels established in KSA environmental noise standards. Annoyance analysis revealed that high percentages of the District inhabitants were highly annoyed, depending on the type of planning zone and period of interest. These results reflect the urgent need to consider environmental noise reduction in KSA national plans. The accuracy of the predicted noise levels and the availability of most of the necessary data should encourage further studies on the use of noise mapping as part of noise reduction plans