Slope stability and avalanching of sediments, the effects of biological activity

An experimental analysis has been conducted on the stability of sediment slopes. This has included a study of the geotechnical properties of sediments and the effects of supporting medium and biological activity on avalanching. The thesis is divided into six sections with three appendices. Section 1: Section one describes the geotechnical properties of Ardmore Bay sediments including particle size distribution, and the phase properties of void ratio, porosity, specific gravity, dry density and bulk density. Section 2: Experiments were conducted on the effects of orientation and shape of the container, volume of sediment, and particle size, on angles of avalanche and repose. Section 3 and 4: Experiments were conducted on the effects of air, water, 50% glycerol. 100% glycerol and alginic acid (low viscosity) on angles of avalanche and angles of repose at successive intervals of time (termed setting time). Section 5: The objectives of the biological experiment were to quantify the effects of biological activity on avalanching. Section 6: The objectives of the Mytilus edulis experiment were to quantify the production of byssus threads in relation to sediment stability. The results of the experiments reported in sections one to six are discussed in relation to mechanisms controlling slope stability in terrestrial and aquatic environments. They are also considered with reference to environmentally friendly methods of stabilising slopes now under active investigation by civil engineers. Topics covered include geotechnical properties, sediment phase relations, fluid viscosity, factors of safety, duration of avalanche and biological activity. I have also discussed slope failure mechanisms, and parallel between engineering and biological stabilisation of slopes. The appendices include geotechnical details of the sediment properties and phase relationships of sediments, sediment permeability, and sediment shear strength. I have also included details of factors of safety and stability analysis of slopes, treated from a civil engineering point of view

To evaluate the role of sonography as an adjunct to mammography in women with dense breasts

OBJECTIVE: To assess the role of sonography as an adjunct to mammography in women with dense breast tissue by determining yield and validity of sonography using histopathology/follow-up mammography as gold standard. METHODS: It was a descriptive analytical study conducted at the Radiology Department of Aga Khan University Hospital, from September 2005 to April 2007. A total of 76, mammographically dense breasts were evaluated with ultrasound. Of these 32 had palpable lumps on mammography, and were excluded from the study. A total of 44 patients had either symptoms of vague nodularity, nipple discharge, mastalgia or had no symptoms and the mammograms showed dense breast parenchyma without any focal abnormality. All these patients underwent whole breast ultrasound. The findings on ultrasound and subsequent histopathology and follow-up mammography were used to calculate the sensitivity, specificity, positive and negative predictive value of whole breast ultrasound as an adjunct to mammography. RESULTS: The age range of patients was 35 to 56 years, mean age was 42 +/- 7.33 years. Of the 44 patients included, 37 had normal ultrasound examinations and had the same findings on one year follow-up mammograms and ultrasound examinations. The remaining, seven patients were categorized as BI RADS category 4 due to presence of suspicious findings on ultrasound examination. They underwent ultrasound guided biopsy of the detected lesions. Out of seven solid lesions biopsied six were benign and one was reported malignant on histopathological examination. The sensitivity, specificity, positive and negative predictive values were 100%, 85%, 14% and 86% respectively. CONCLUSION: Breast ultrasound can be a useful adjunct to mammography in women with dense breast by detecting small cancers not identified on mammography or clinical breast examination. Larger studies will be required to suggest that ultrasound could be used as an adjunct

Mammographic criteria for determining the diagnostic value of microcalcifications in the detection of early breast cancer

Objective: To evaluate the importance of microcalcifications in the detection of breast carcinoma in conventional mammography.Methods: This prospective study was carried out at Aga Khan University Hospital (AKUH). Mammograms of 68 patients with microcalcifications were evaluated. Craniocaudal and oblique views of both breasts were acquired on routine basis with cone compression and magnified views when required.Results: Among 68 patients with microcalcifications, 61 (89%) had clustered microcalcifications while 7 patients (10.29%) had scattered microcalcifications. Microcalcifications can occur in benign and malignant diseases. While evaluating clustered microcalcifications, few criteria have been established to determine malignant clustered microcalcifications, these include specific and nonspecific criteria. Among specific and statistically significant criteria for malignant microcalcifications, which were identified in this study, were irregularity of size, irregularity of density, linear or branched shape and Le Gal\u27s type V distribution. In a cluster total number of \u3e30 microcalcifications and at least 10 microcalcifications/cm2 of a cluster are also important in diagnosing a malignant cluster, but are included in nonspecific criteria because they can be present in benign diseases also. Scattered bilateral microcalcifications are usually present in benign breast diseases, but in this study, two patients with breast cancer had profuse bilateral scattered microcalcifications.CONCLUSION: This study shows that specific and statistically significant criteria for malignant microcalcifications, are irregularity of size, irregularity of density, linear or branched shape and Le Gal\u27s type V distribution. Scattered bilateral microcalcifications are usually present in benign breast diseases, but irregular shape and development of new calcifications among diffusely scattered bilateral calcifications, on follow up study, should also raise suspicion for being malignant

Hybrid particle swarm optimization for robust digital image watermarking

This paper presents an image watermarking algorithm for the optimization between robustness and transparency which is recently considered as one of the most challenging issues. The novelty is to associate the Hybrid Particle Swarm Optimization (HPSO), instead of a single optimization, as a model with singular value decomposition (SVD). To embed and extract the watermark, the singular values of the blocked host image are modified according to the watermark and scaling factors. A series of training patterns are constructed by employing between two images. Moreover, the work takes accomplishing maximum robustness and transparency into consideration. HPSO method is used to estimate the multiple parameters involved in the model. Simulation results demonstrated that the proposed scheme can effectively improve the quality of the watermarked image and resist common image manipulations such as adding noise, resizing compression, tempering, etc. and some geometric attacks

Retrospective cost-utility and budget impact assessments of Hypericum perforatum in contrast with Fluoxetine treatment for depression in Karachi, Pakistan

In this study we have compared two different types of therapies i.e. herbal and allopathic system of therapies for Depression and studied them from the social perspectives. The Hypericum perforatum is compared with Fluoxetine [HCL] in terms of cost-utility and financial savings thereby evaluating its influence on annual expenditure of depressive patients that were randomly selected from 178 union councils of the city of Karachi, Pakistan. For both system of therapies a total of 356 patients were selected by stratified random sampling. Taking frequency of depression as ‘1’ annually with discount rate at 3% for calculating the burden-of-illness in terms of disability-adjusted-life-years. The cost-utility and the budget-impact assessments were carried out to assess incremental-cost-effectiveness-ratio, and the budget-impact-per-onset as well as budget-impact-per-year values. In comparison with the Fluoxetine therapy, the Hypericum perforatum was found to relieve symptoms in 21.47% less cost; owing 29.23% less disability-adjusted-life-years and 21.45% less budget-impact-per-onset as well as budget-impact-peryear. The annual mean incremental-cost-effectiveness-ratio was found to be at 36.95±270.74 (less than GDP per capita threshold of Rs. 38,173.02). Hypericum perforatum provide the optimal utility with less impact on budget of a patient in comparison with the treatment of symptoms of depression with Fluoxetine

Evaluation of Knowledge and Belief on False Reports and Misinformation from Social Media in COVID-19 Pandemic: A Web Based Cross-Sectional Survey in Karachi, Pakistan

COVID-19 has become a global pandemic declared by World Health Organization (WHO) on March 11, 2020. This has put drastic impact on the world and many lives have been affected globally. As the cases of COVID-19 infected are increasing, the spread of fake news related to treatment and its prevention have led to a very difficult situation in controlling and containing the COVID-19 infection. It seems that general public tend to belief in rumors and share them on social media platforms that lead to misinformation which go viral and has created chaos among the general masses. The study evaluated the role of social media in false reporting and spreading misinformation in COVID-19 pandemic. Study also evaluated the knowledge, belief and awareness among general population of the Karachi city to provide insights and to enable ministries and policy makers to take suitable measures. This is a cross sectional study which was conducted from June to July 2020 in Karachi, Pakistan. A self-structured questionnaire was administered through Facebook and Whatsapp due to lockdown and increase risk of exposure from COVID-19 to the research assistants. Data collected was analyzed using descriptive and inferential statistics of frequency counts, and percentages of quantitative variables and Chi square for the inferential variable at 0.05 level of significance. A total of 267 participants were sampled for the study. The study indicates that majority of the participants believed in the myths and false reports circulated on social media and usually share and forward such news without authentic references

Segmentation of Brain Magnetic Resonance Images (MRIs): A Review

Abstract MR imaging modality has assumed an important position in studying the characteristics of soft tissues. Generally, images acquired by using this modality are found to be affected by noise, partial volume effect (PVE) and intensity nonuniformity (INU). The presence of these factors degrades the quality of the image. As a result of which, it becomes hard to precisely distinguish between different neighboring regions constituting an image. To address this problem, various methods have been proposed. To study the nature of various proposed state-of-the-art medical image segmentation methods, a review was carried out. This paper presents a brief summary of this review and attempts to analyze the strength and weaknesses of the proposed methods. The review concludes that unfortunately, none of the proposed methods has been able to independently address the problem of precise segmentation in its entirety. The paper strongly favors the use of some module for restoring pixel intensity value along with a segmentation method to produce efficient results

Diabetes Diagnosis through Machine Learning: An Analysis of Classification Algorithms

Diabetes is a serious and chronic disease characterized by high levels of sugar in the blood. If left untreated, it can lead to numerous complications. In the past, diagnosing diabetes required a visit to a diagnostic center and consultation with a doctor. However, the use of machine learning can help to identify the disease earlier and more accurately. This study aimed to create a model that can accurately predict the likelihood of diabetes in patients using three machine learning classification algorithms: Logistic Regression (LR), Decision Tree (DT), and Naive Bayes (NB). The model was tested on the Pima Indians Diabetes Database (PIDD) from the UCI machine learning repository and the performance of the algorithms was evaluated using various metrics such as accuracy, precision, F-measure, and recall. The results showed that Logistic Regression had the highest accuracy at 71.39% outperforming the other algorithms

Economic Analysis of Hybrid Maize Cultivation in Distt; Naushahro Feroze, Sindh, Pakistan

The purpose of this study was to investigate economic analysis of hybrid maize cultivation in distt;Naushro feroze Sindh .This study was based on primary data which was collected from a total of 105 farmersselected by random sampling. Simple descriptive statistical tools like Means, Percentages and Frequencies wereapplied to analyze the data. The results of this study revealed that the total fixed cost was reported as Rs, 18225.0per acre, the variable cost consists on labor, capital, Rs: 31800 respectively. The total cost of production wasestimated as Rs. 50000 per acre. The physical productivity was calculated as 104.5 mnds per acre. Furthermore,the revenue productivity, which is measured as income, received by the farmer in term of money was estimatedas Rs. 118607.5 per acre. The net return as found to be Rs. 68607.5 per acre, the cost of production ratio and costof benefit ratio were calculated as 1:2.37 and 1:1.37 respectively, Therefore our study suggest that Sindh SeedCorporation should produce hybrid varieties of seed in sufficient quantity to meet the increase demand offarmers on regular basis to provide them, Government should develop go-downs for the storage of maize grinsfor long term and institutional Banks should provide loans at low interest rates

Breast imaging reports for malignant lesions: Are we maintaining recommended BI-RADS® lexicon standards

Background: The purpose of this study was to evaluate mammography reports for diagnosed breast cancer cases in major government and private centers in Karachi, Pakistan, with respect to concordance with the Breast Imaging Reports And Data System (BI-RADS®) lexicon.Methods: A prospective, descriptive, multicenter study was conducted in the radiology sections of the Aga Khan University Hospital, Pakistan Naval Station Shifa Hospital, Advanced Radiology Clinic, Karachi Institute of Radiotherapy and Nuclear Medicine, and Civil Hospital Karachi between May and October 2010 after approval from the ethical review committee of Aga Khan University. Mammograms reported as BI-RADS category 4 and 5 were included in the study. Mammograms reported as BI-RADS category 0, 1, 2 and 3 were excluded. Fifty reports were collected from each center. Data were collected about the clinical indication, breast density, location and description of the lesion, calcification, and comments on axillary lymph nodes. This description was compared with the BI-RADS lexicon.Results: The mean age of the patients was 50 ± 12 years. The clinical indication, breast parenchymal density, lesion location, and presence of calcification were better described by the private centers, while description of lymph node status was better stated by the government centers. This difference was statistically significant, except for lesion description. The description of masses by the two reporting groups was comparable.Conclusion: Mammographic reporting of malignant breast lesions in the private sector is more in line with the BI-RADS lexicon, as compared with government sector hospitals in Karachi, Pakistan. Lymph node documentation was better in government sector reports