A practical protocol for the experimental design of comparative studies on water treatment

The design and execution of effective and informative experiments in comparative studies on water treatment is challenging due to their complexity and multidisciplinarity. Often, environmental engineers and researchers carefully set up their experiments based on literature information, available equipment and time, analytical methods and experimental operations. However, because of time constraints but mainly missing insight, they overlook the value of preliminary experiments, as well as statistical and modeling techniques in experimental design. In this paper, the crucial roles of these overlooked techniques are highlighted in a practical protocol with a focus on comparative studies on water treatment optimization. By integrating a detailed experimental design, lab experiment execution, and advanced data analysis, more relevant conclusions and recommendations are likely to be delivered, hence, we can maximize the outputs of these precious and numerous experiments. The protocol underlines the crucial role of three key steps, including preliminary study, predictive modeling, and statistical analysis, which are strongly recommended to avoid suboptimal designs and even the failure of experiments, leading to wasted resources and disappointing results. The applicability and relevance of this protocol is demonstrated in a case study comparing the performance of conventional activated sludge and waste stabilization ponds in a shock load scenario. From that, it is advised that in the experimental design, the aim is to make best possible use of the statistical and modeling tools but not lose sight of a scientific understanding of the water treatment processes and practical feasibility

Would credit scoring work for Islamic finance? A neural network approach

Purpose – The main aim of this paper is to distinguish whether the decision making process of the Islamic financial houses in the UK can be improved through the use of credit scoring modeling techniques as opposed to the currently used judgmental approaches. Subsidiary aims are to identify how scoring models can reclassify accepted applicants who later are considered as having bad credit and how many of the rejected applicants are later considered as having good credit; and highlight significant variables that are crucial in terms of accepting and rejecting applicants which can further aid the decision making process. Design/methodology/approach – A real data-set of 487 applicants are used consisting of 336 accepted credit applications and 151 rejected credit applications make to an Islamic finance house in the UK. In order to build the proposed scoring models, the data-set is divided into training and hold-out sub-set. The training sub-set is used to build the scoring models and the hold-out sub-set is used to test the predictive capabilities of the scoring models.70 percent of the overall applicants will be used for the training sub-set and 30 percent will be used for the testing sub-set. Three statistical modeling techniques namely Discriminant Analysis (DA), Logistic Regression (LR) and Multi-layer Perceptron (MP) neural network are used to build the proposed scoring models. Findings – Our findings reveal that the LR model has the highest Correct Classification (CC) rate in the training sub-set whereas MP outperforms other techniques and has the highest CC rate in the hold-out sub-set. MP also outperforms other techniques in terms of predicting the rejected credit applications and has the lowest Misclassification Cost (MC) above other techniques. In addition, results from MP models show that monthly expenses, age and marital status are identified as the key factors affecting the decision making process. Research limitations/implications – Although our sample is small and restricted to an Islamic Finance house in the UK the results are robust. Future research could consider enlarging the sample in the UK and also internationally allowing for cultural differences to be identified. The results indicate that the scoring models can be of great benefit to Islamic finance houses in regards to their decision making processes of accepting and rejecting new credit applications and thus improve their efficiency and effectiveness. Originality/value –Our contribution is the first to apply credit scoring modeling techniques in Islamic Finance. Also in building a scoring model our application applies a different approach by using accepted and rejected credit applications instead of good and bad credit histories. This identifies opportunity costs of misclassifying credit applications as rejected

Complete mesocolic excision does not increase short-term complications in laparoscopic left-sided colectomies : a comparative retrospective single-center study

Background: Since the implementation of total mesorectal excision (TME) in rectal cancer surgery, oncological outcomes improved dramatically. With the technique of complete mesocolic excision (CME) with central vascular ligation (CVL), the same surgical principles were introduced to the field of colon cancer surgery. Until now, current literature fails to invariably demonstrate its oncological superiority when compared to conventional surgery, and there are some concerns on increased morbidity. The aim of this study is to compare short-term outcomes after left-sided laparoscopic CME versus conventional surgery. Methods: In this retrospective analysis, data on all laparoscopic sigmoidal resections performed during a 3-year period (October 2015 to October 2018) at our institution were collected. A comparative analysis between the CME group-for sigmoid colon cancer-and the non-CME group-for benign disease-was performed. Results: One hundred sixty-three patients met the inclusion criteria and were included for analysis. Data on 66 CME resections were compared with 97 controls. Median age and operative risk were higher in the CME group. One leak was observed in the CME group (1/66) and 3 in the non-CME group (3/97), representing no significant difference. Regarding hospital stay, postoperative complications, surgical site infections, and intra-abdominal collections, no differences were observed. There was a slightly lower reoperation (1.5% versus 6.2%, p = 0.243) and readmission rate (4.5% versus 6.2%, p = 0.740) in the CME group during the first 30 postoperative days. Operation times were significantly longer in the CME group (210 versus 184 min, p < 0.001), and a trend towards longer pathological specimens in the CME group was noted (21 vs 19 cm, p = 0.059). Conclusions: CME does not increase short-term complications in laparoscopic left-sided colectomies. Significantly longer operation times were observed in the CME group

Retrospective comparative study of bone loss in implants with and without immediate loading in the Egas Moniz university clinic

To evaluate bone loss after three years in implants placed at the implantology consult at the Egas Moniz University Clinic, relating bone loss to the type of loading (conventional or immediate load). A comparative and retrospective study, performed on a sample of 65 implants, placed in 24 of 327 patients, who attended the implantology consult at the Egas Moniz University Clinic in 2015, representing 7.3% of the study population through the measurement of distance between implant platform and bone using radiographs. Three years after implant placement with and without immediate loading there is statistically significant bone loss mesially and distally. It was found that when compared bone loss in loaded vs unloaded mesially and distally implants, there were no statistically significant differences. The bone loss of the unloaded implants was compared three years after being placed, with the bone level of the loaded implants also three years later. No significant difference was found. Although no statistically significant differences were found between bone loss in loaded implants vs unloaded mesially and distally, as it is supported by the literature, it was possible to conclude that there was, in fact, a statistically significant bone loss, mesially and distally, three years after implant placement with and without immediate loading. This may be due to poor oral hygiene, a history of periodontitis, smoking and peri-implantitis.info:eu-repo/semantics/publishedVersio

Comparison of osseointegration in piezoimplants versus cylindrical implants

BACKGROUND: Dental implants have been successful for the restoration of edentulous areas, but current techniques are inadequate in areas lacking sufficient bone volume. Piezoelectric surgery has shown encouraging effects on both osseous healing. A new wedge-shaped titanium PiezoImplant requires piezoelectric osteotomy. This study compares PiezoImplants to conventional threaded cylindrical shaped implants by microcomputed tomography and histology to assess osseointegration, tissue response, and alveolar ridge changes. METHODS: After 3 months post-extraction, 18 conventional cylindrical implants and 18 wedge-shaped PiezoImplants were placed using a split-mouth design in 3 adult mini pigs. The cylindrical implant sites were prepared for osteotomy with rotary instrumentation while the PiezoImplant sites were prepared with piezoelectric surgical inserts. One animal was sacrificed at 4, 8, and 12 weeks post operation. Quantitative µCT and histological analysis evaluated bone volume, osseointegration, and post-operative cellular events. RESULTS: The results of a multivariable linear regression model demonstrated that the PiezoImplants, arch location, and time were significant factors on higher BV/TV percentage. Bone to implant contact (BIC) analysis by high resolution microscopy and histomorphometry indicated osseointegration though intimate contact between implants and adjacent alveolar bone in both groups. The tissue response displayed no evidence of abnormal healing and the PiezoImplant was classified as a non-irritant. CONCLUSION: The combination of piezoelectric osteotomy and newly designed PiezoImplants had favorable effects on wound healing and osseointegration compared to conventional cylindrical implants. These novel wedge-shaped implants may be beneficial for narrow ridge spaces without additional ridge augmentation. Further research is needed to establish clinical validity

Type and Timing of Rehabilitation Following Acute and Subacute Spinal Cord Injury: A Systematic Review

Objectives: The objective of this study was to conduct a systematic review of the literature to address the following clinical questions: In adult patients with acute and subacute complete or incomplete traumatic SCI, (1) does the time interval between injury and commencing rehabilitation affect outcome?; (2) what is the comparative effectiveness of different rehabilitation strategies, including different intensities and durations of treatment?; (3) are there patient or injury characteristics that affect the efficacy of rehabilitation?; and (4) what is the cost-effectiveness of various rehabilitation strategies? Methods: A systematic search was conducted for literature published through March 31, 2015 that evaluated rehabilitation strategies in adults with acute or subacute traumatic SCI at any level. Studies were critically appraised individually and the overall strength of evidence was evaluated using methods proposed by the GRADE (Grades of Recommendation Assessment, Development and Evaluation) working group. Results: The search strategy yielded 384 articles, 19 of which met our inclusion criteria. Based on our results, there was no difference between body weight–supported treadmill training and conventional rehabilitation with respect to improvements in Functional Independence Measure (FIM) Locomotor score, Lower Extremity Motor Scores, the distance walked in 6 minutes or gait velocity over 15.2 m. Functional electrical therapy resulted in slightly better FIM Motor, FIM Self-Care, and Spinal Cord Independence Measure Self-Care subscores compared with conventional occupational therapy. Comparisons using the Toronto Rehabilitation Institute Hand Function Test demonstrated no differences between groups in 7 of 9 domains. There were no clinically important differences in Maximal Lean Test, Maximal Sidewards Reach Test, T-shirt Test, or the Canadian Occupational Performance Measure between unsupported sitting training and standard in-patient rehabilitation. Conclusion: The current evidence base for rehabilitation following acute and subacute spinal cord injury is limited. Methodological challenges have contributed to this and further research is still needed. © 2017, © The Author(s) 2017

Tool for fast mismatch analysis of analog circuits

A tool is presented that evaluates statistical deviations in performance characteristics of analog circuits, starting from statistical deviations in the technological parameters of MOS transistors. Performance is demonstrated via the analysis of a Miller OTA in two different configurations and a linearized CMOS transconductor. The CPU time is reduced by a factor of 25 to 90 with respect to conventional Monte Carlo simulation, while maintaining similar accuracy in the computations

Bonding with Self-Etching Primers - Pumice or Pre-Etch? An In Vitro Study

The objective of this study was to compare the shear bond strengths (SBS) of orthodontic brackets bonded with self-etching primer using different enamel surface preparations. A 2-by-2 factorial study design was used. Sixty human premolars were harvested, cleaned and randomly assigned to four groups (n=15/group). Teeth were bathed in saliva for 48 hours to form a pellicle. Treatments were assigned as follows: Group 1 was pumiced for 10 seconds and pre-etched for five seconds with 37% phosphoric acid before bonding with self-etching primer (Transbond Plus). Group 2 was pumiced for ten seconds before bonding. Group 3 was pre-etched for five seconds before bonding. Group 4 had no mechanical or chemical preparation before bonding. All teeth were stored in distilled water for 24 hours at 37oC before debonding. The SBS values and Adhesive Remnant Index (ARI) score were recorded. Scanning electron microscopy (SEM) was used to investigate the enamel changes at each stage of surface preparation and bonding. The SBS values (±1 SD) for Groups 1-4 were 22.9±6.1, 16.1±7.3, 36.2 ±8.2, and 13.1±10.1 MPa, respectively. Two-way ANOVA and subsequent contrasts showed statistically significant differences among treatment groups. ARI scores indicated the majority of adhesive remained on the bracket for all 4 groups. SEM micrographs showed variable enamel surface roughness depending upon preparation. In conclusion, pre-etching the bonding surface for five seconds with 37% phosphoric acid, instead of pumicing, when using self-etching primers to bond orthodontic brackets, results in greater shear bond strengths

Model Verification and the Likelihood Principle

The likelihood principle (LP) is typically understood as a constraint on any measure of evidence arising from a statistical experiment. It is not sufficiently often noted, however, that the LP assumes that the probability model giving rise to a particular concrete data set must be statistically adequate—it must “fit” the data sufficiently. In practice, though, scientists must make modeling assumptions whose adequacy can nevertheless then be verified using statistical tests. My present concern is to consider whether the LP applies to these techniques of model verification. If one does view model verification as part of the inferential procedures that the LP intends to constrain, then there are certain crucial tests of model verification that no known method satisfying the LP can perform. But if one does not, the degree to which these assumptions have been verified is bracketed from the evidential evaluation under the LP. Although I conclude from this that the LP cannot be a universal constraint on any measure of evidence, proponents of the LP may hold out for a restricted version thereof, either as a kind of “ideal” or as defining one among many different forms of evidence