Bayesian estimation of the transmissivity spatial structure from pumping test data

Estimating the statistical parameters (mean, variance, and integral scale) that define the spatial structure of the transmissivity or hydraulic conductivity fields is a fundamental step for the accurate prediction of subsurface flow and contaminant transport. In practice, the determination of the spatial structure is a challenge because of spatial heterogeneity and data scarcity. In this paper, we describe a novel approach that uses time drawdown data from multiple pumping tests to determine the transmissivity statistical spatial structure. The method builds on the pumping test interpretation procedure of Copty et al. (2011) (Continuous Derivation method, CD), which uses the time-drawdown data and its time derivative to estimate apparent transmissivity values as a function of radial distance from the pumping well. A Bayesian approach is then used to infer the statistical parameters of the transmissivity field by combining prior information about the parameters and the likelihood function expressed in terms of radially-dependent apparent transmissivities determined from pumping tests. A major advantage of the proposed Bayesian approach is that the likelihood function is readily determined from randomly generated multiple realizations of the transmissivity field, without the need to solve the groundwater flow equation. Applying the method to synthetically-generated pumping test data, we demonstrate that, through a relatively simple procedure, information on the spatial structure of the transmissivity may be inferred from pumping tests data. It is also shown that the prior parameter distribution has a significant influence on the estimation procedure, given the non-uniqueness of the estimation procedure. Results also indicate that the reliability of the estimated transmissivity statistical parameters increases with the number of available pumping tests.Peer ReviewedPostprint (author's final draft

Relationship between handedness and toothbrush-related cervical dental abrasion in left- and right-handed individuals

AbstractBackground/purposeCervical tooth abrasion is the loss of tooth material at the cementoenamel junction, and is usually related to faulty brushing habits. In this study, we attempted to evaluate the effects of handedness on tooth-brushing abrasion in terms of brushing habits in left- and right-handed adults.Materials and methodsIn total, 488 subjects participating in the study were divided into 2 groups according to hand preference (group I; left-handed and group II; right-handed), and were interviewed about their brushing habits, and their clinical oral conditions such as the plaque index (PI), gingival index (GI), and tooth wear index (TWI) were determined. Handedness was determined by a questionnaire that focused on handedness using the Turkish version of the Edinburgh Handedness Inventory.ResultsThis study showed that there were no statistically significant differences between groups I and II according to daily tooth-brushing habits, PI, or GI. Statistically significant differences were found between men and women according to the clinical oral scores and brushing habits (P<0.01). However, there were no statistically significant differences between the mean TWI scores of left- and right-handed groups (P=0.12). It was found that an increased frequency and longer duration of tooth-brushing significantly increased the TWI scores in both groups (P<0.01). It was also found that TWI scores were statistically higher in subjects who brushed horizontally rather than vertically (P<0.01). Correlations between clinical oral scores (TWI, PI, and GI) and brushing habits were statistically significant (P<0.01).ConclusionThe oral-hygiene performance of females was better than males. Brushing habits of patients were related to the severity of cervical wear. But no statistically significant relationship was found between hand preference and tooth-brushing abrasion in this study

Ultrasound evaluation of metabolic syndrome patients with hepatosteatosis

Objective: The exact incidence of hepatosteatosis in patients with metabolic syndrome (MetS) is unknown; also there is no valid, simple and inexpensive method to evaluate and follow-up for patients with MetS. In our study, we aimed to demonstrate the frequency of hepatosteatosis, and whether demonstrate presence and degree of steatosis using liver ultrasonography may provide additional benefit for evaluating and following-up in MetS patients with non-alcoholic fatty liver disease. Methods: One hundred and twelve patients with MetS were included to the study. Patients divided into three groups; control group (n= 36) consisted of patients without hepatosteatosis, group 1 (n=43) consisted of patients with grade 1 hepatosteatosis. Finally, group 2 (n= 33) consisted of patients with grade 2 hepatosteatosis. The relationship between the presence and degree of the hepatosteatosis and MetS parameters were analyzed.Results: The incidence of hepatosteatosis was found 69.4% in patients with MetS. There were significantly differences in HOMA-IR, AST, ALT and GGT levels among control group and group 1 (p<0.05 for all). There were also significantly differences in waist circumference, fasting blood glucose, fasting insulin, HOMA-IR, AST, ALT, GGT, ferritin, CRP, sedimentation, uric acid and microalbuminuria levels among control group and group 2 (p<0.05 for all). Blood pressures and lipid profiles were similar among all groups (p>0.05 for all). Besides, there were significantly differences in waist circumferences, fasting insulin, HOMA-IR, GGT, uric acid, CRP levels among group 1 and 2 (p<0.05 for all).Conclusion: Our study indicates that MetS related parameters; especially insulin resistance, were significantly different in patients with hepatosteatosis compared to patients without hepatosteatosis. Because of the different measurment of waist circumferences among groups, we recommend to use liver ultrasonography and waist circumference together to evaluate and follow-up for MetS patients with hepatosteatosis. J Clin Exp Invest 2013; 4 (2): 153-158Key words: Fatty Liver, metabolic syndrome X, ultrasonograph

Ultrafine conducting fibers: metallization of poly(acrylonitrile-co-glycidyl methacrylate) nanofibers

Electrospun poly(glycidylmethacrylate) (PGMA) and poly(acrylonitrile-co-glycidyl methacrylate) (P(AN-GMA)) nanofibers were coated with monodisperse silver nanoparticles by using an electroless plating technique at ambient conditions. Oxirane groups on the surface of nanofibers were replaced with reducing agent, hydrazine. Surface modified nanofibers were allowed to react with ammonia solution of AgNO3. A redox reaction takes place and metallic silver nucleate on fibers surface. Parameters affecting the particle size were determined

Magnetic resonance dacryocystography: Its role in the diagnosis and treatment plan of lacrimal drainage system obstructions

Objective: To evaluate the role of magnetic resonance dacryocystography (MR-DCG) technique in patients with obstruction of lacrimal drainage system. Methods: A total of 40 patients who had presented to the ophthalmology clinic were suspected to have obstruction of lacrimal drainage system, were evaluated with MR-DCG after instillation of 0.5% Gd-DTPA conjunctival contrast medium. Dacryocystorhinostomy (DCR) was performed in patients who were found to have lacrimal drainage system obstruction on either side on MR-DCG. Results: Obstruction of lacrimal drainage system was successfully detected in a total of 49 eyes of 40 patients undergoing examination with MR-DCG. The MR-DCG findings of 29 nasolacrimal systems were compared with the intraoperative findings in 28 out of 40 patients who had undergone the DCR operation. The sensitivity of MR-DCG was determined as 100% and specificity as 96.7% for identification of nasolacrimal system obstruction when compared with the intraoperative findings, and MR-DCG was found to detect obstruction with high accuracy. Conclusion: MR-DCG has a high success rate in detection of lacrimal drainage system obstructions and the level and cause of the obstruction

Effect of bevacizumab, which remain after withdrawal of the first dose/s from a single-use vial on diabetic macular edema

Background: The objective of this study was to investigate the effect of bevacizumab remaining after withdrawal of the first dose/s from a single-use vial in diabetic macular edema (DME) secondary to diabetic retinopathy.Methods: Patients were divided into four groups according to duration of storage of the single-use vial of bevacizumab in the refrigerator: Group 1 received IVB when the vial was first opened, and Groups 2, 3, and 4 received IVB after 3, 7, and 15 days, respectively, after the first dose or doses had been withdrawn with an insulin (27-gauge) needle from the single-use vial. The Wilcoxon test was used to compare the results in four groups. p&lt;0.05 was considered as statistically significant.Results: Mean age, mean glycosylated hemoglobin, severe of retinapathy and status of the lens were similar in all groups (p&gt;0.05). Preinjection mean best corrected visual acuity (BCVA) was 0.41±0.2; 0.39±0.2; 0.39±0.2 and 0.34±0.2 logMAR Group 1, 2, 3 and 4, respectively. Preinjection mean central macular thickness (CMT) was 503±88; 502±99; 565±63 and 491±107 µm in Group 1, 2, 3 and 4, respectively. After injection mean BCVA was 0.30±0.16; 0.28±0.20; 0.29±0.19 and 0.25±0.20 logMAR and mean CMT was 321±75; 315±97; 360±83 and 279±82 in Group 1, 2, 3 and 4, respectively. The mean BCVA increased significantly, and CMT decreased significantly after injection in all groups. No observed serious ophthalmologic or systemic side effects.Conclusion: Bevacizumab which remain in the single use vial after first dose/s is safe and effective for treatment of DME. These results are useful for poor countries

A taxonomy of social media for learning

The use of social media in the classroom has the potential to improve learning outcomes for both lecturers and university students. This paper presents a framework for how social media can be used as a tool in the learning process according to educational objectives. The framework is intended to demonstrate to researchers and lecturers how to activate social media platforms effectively as a learning tool; how several platforms can be employed across subjects; and how to unify social media resources with the physical and virtual learning environment. To support these areas and provide an innovative and sustainable way to transform teaching and learning, a social media (Web 2.0) taxonomy was developed. The purpose of the social media taxonomy is to assist lecturers in planning all the steps of learning, teaching, and assessing a course or topic, whilst considering the learning goals reflected in national and local curriculum standards. The Web 2.0 taxonomy focuses on three dimensions named as Consciousness, Cognition, and Creativity [3C]. Each dimension consists of its categories in the metacognitive domain: Consciousness, viewing, Cognition, posting, interacting, and analysing, and Creativity, evaluating, and curating. The categories are used to hierarchize instructional objectives, ranging from lower-order thinking to higher-order thinking skills. Each level of the taxonomy is built on the previous learning level by moving from the concrete to the abstract and from the simple to the complex. Thus, when students have completed all these levels, they can be considered to have mastered certain learning objectives, equipping them with innovative 21st-century skills

Essays in optimal taxation

The mismatch between wealth level and entrepreneurial ability creates productive inefficiency in the market and under financial frictions, the credit market may not be able to solve this problem. In such a world, decreasing wealth inequality with capital taxation might be helpful in bringing the economy to its production possibilities frontier but capital taxation is costly as it distorts wealth creation. I derive optimal capital tax formulas that reflect this trade-off between productive efficiency benefit and wealth accumulation cost of capital taxes. With numerical analysis, I show that when the mismatch is high, government tends to intervene in the economy more and optimal capital taxes are higher. Also, having a lower elasticity of labor with respect to wage for agents leads to higher optimal taxation rate