>Magister Scientiae - MSc / An accurate prediction of pore pressure is an essential in reducing the risk involved in a well or field life cycle. This has formed an integral part of routine work for exploration, development and exploitation team in the oil and gas industries. Several factors such as sediment compaction, overburden, lithology characteristic, hydrocarbon pressure and capillary entry pressure contribute significantly to the cause of overpressure. Hence, understanding the dynamics associated with the above factors will certainly reduce the risk involved in drilling and production. This study examined three deep water drilled wells GA-W1, GA-N1, and GA-AA1 of lower cretaceous Hauterivian to early Aptian age between 112 to 117.5 (MA) Southern Pletmos sub-basin, Bredasdorp basin offshore South Africa. The study aimed to determine the pore pressure prediction of the reservoir formation of the wells. Eaton’s resistivity and Sonic method are adopted using depth dependent normal compaction trendline (NCT) has been carried out for this study. The variation of the overburden gradient (OBG), the Effective stress, Fracture gradient (FG), Fracture pressure (FP), Pore pressure gradient (PPG) and the predicted pore pressure (PPP) have been studied for the selected wells. The overburden changes slightly as follow: 2.09g/cm3, 2.23g/cm3 and 2.24g/cm3 across the selected intervals depth of wells. The predicted pore pressure calculated for the intervals depth of selected wells GA-W1, GA-N1 and GA-AA1 also varies slightly down the depths as follow: 3,405 psi, 4,110 psi, 5,062 psi respectively. The overpressure zone and normal pressure zone were encountered in well GA-W1, while a normal pressure zone was experienced in both well GA-N1 and GA-AA1. In addition, the direct hydrocarbon indicator (DHI) was carried out by method of post-stack amplitude analysis seismic reflectors surface which was used to determine the hydrocarbon prospect zone of the wells from the seismic section. It majorly indicate the zones of thick hydrocarbon sand from the amplitude extraction grid map horizon reflectors at 13AT1 & 8AT1 and 8AT1 & 1AT1 of the well GA-W1, GA-N1 and GA-AA1 respectively. These are suggested to be the hydrocarbon prospect locations (wet-gas to Oil prone source) on the seismic section with fault trending along the horizons. No bright spot, flat spot and dim spot was observed except for some related pitfalls anomalies

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When a cloud user allocates a cluster to execute a map-reduce workload, the user must determine the number and type of virtual machine instances to minimize the workload's financial cost. The cloud user may rent on-demand instances at a fixed price or spot instances at a variable price to execute the workload. Although the cloud user may bid on spot virtual machine instances at a reduced rate, the spot market auction may delay the workload's start or terminate the spot instances before the workload completes. The cloud user requires a forecast for the workload's financial cost and completion time to analyze the trade-offs between on-demand and spot instances. While existing estimation tools predict map-reduce workloads' completion times and costs, these tools do not provide spot instance estimates because a spot market auction determines the instance's start time and duration. The ephemeral spot instances impact execution time estimates because the spot market auction forces the map-reduce workloads to use different storage strategies to persist data after the spot instances terminate. The spot market also reduces the existing tools' completion time and cost estimate accuracy because the tool must factor in spot instance wait times and early terminations. This dissertation updated an existing tool to forecast map-reduce workload's monetary cost and completion time based on spot market historical traces. The enhanced estimation tool includes three new enhancements over existing tools. First, the estimation tool models the impact to the execution from new storage strategies. Second, the enhanced tool calculates additional execution time from early spot instance termination. Finally, the enhance tool predicts the workloads wait time and early termination probabilities from historic traces. Based on two historical Amazon EC2 spot market traces, the enhancements reduce the average completion time prediction error by 96% and the average monetary cost prediction error by 99% over existing tools.

The behaviour of spot welded joints is to be studied in shear mode by using the end notched flexure (ENF) specimen. The specimen counts on several spot welds spaced with the same gap along the entire length except for the notch. Different configurations of the test specimen spacing gap and spot diameter are to be preliminary designed in software PTC-CREO 2.0 in order to obtain accurate results. The results obtained from the software are to be compared with the experimental analysis performed by means of a servo-hydraulic testing machine. Both the virtual and the experimental results will be used to extract the stress-shear displacement relation around the first spot weld which is in contact with the notch, that is, the corresponding cohesive law. In addition, a comparison between adhesive and spot weld behaviours will be carried out by means of analytical equations in order to prove an existing equalisation between each other. Despite assuming several sources of error and after facing some problems related to the experimental work, accurate convergences between experimental and theoretical results were not accomplished in any of the three tests performed in lab. Due to the plastic deformation of the specimens in lab, the cohesive law was possible to be extracted only from the theoretical analysis, but not from the experimental one. In its place, the load-shear displacement was extracted. Some alternatives to solve this issue and to improve the performance of the tests are given at the end of this paper.

Chronic noncommunicable diseases (NCDs) are the largest contributor to mortality rates worldwide including in low- and middle- income countries (LMICs) which already suffer from high rates of infectious disease. Among the four major NCDs that cause 38 million deaths annually, cardiovascular disease (CVD) causes 17.5 million of these annual deaths. The primary risk factor of CVD is hypertension. Kenya, a developing country in Sub-Saharan Africa, has a high rate of hypertension with low (2.6%) management rates. Prior research from our lab has identified a population of Kenyans with a high prevalence of hypertension that is not statistically correlated with typical known risk factors such as obesity, hypercholesterolemia, and behaviors of smoking and lack of exercise. This study investigated the hypothesis that high dietary salt consumption and low K+ dietary intake are contributing to the etiology of high blood pressure in this community. To test our hypothesis, two spot urine samples representing nocturnal excretions (evening and morning) and blood pressure measurements were collected from 135 participants. All samples were analyzed for Na+, K+ and Cl- content using the Smartlyte Electrolyte Analyzer. The average of each spot urine sample was extrapolated to an estimated 24-h value by the method of Mills, et al. The overall population mean urine electrolyte excretion values for Na+, K+ and Cl- were 170.6 ± 89.3 mmol/L, 82.0 ± 54.0 mmol/L, and 87.7 ± 42.1 mmol/L, respectively. While these values fall within the suggested levels for Na+ (40-220 mmol/L) and K+ (25-125 mmol/L), they are under normal excretion levels for Cl- (110-250mmol/L). Overall ion excretion was higher in females than males, although only K+ values were statistically significant (p < 0.05). Analysis of Na+ and Cl- excretion from individuals stratified by blood pressure, revealed significant differences (p < 0.05) between normotensive and hypertensive stage I individuals for both electrolytes (57.9 mmol/L vs. 88.9 mmol/L and 65.5 mmol/L vs. 96.7 mmol/L, respectively). Overall, these results suggest that our sample population consumes dietary salt within a normal range and thus, the observed prevalence of hypertension likely results from other genetic and environmental factors.

White spot lesions (WSLs) or decalcifications remain a common complication in orthodontic patients with poor oral hygiene. The purpose of this study was to compare attitudes regarding the development of WSLs among patients, parents, orthodontists and general dentists and improve prevention and treatment protocols through better communication. A survey was developed to evaluate and compare the current opinions of orthodontic patients (n=315), parents (n=279), orthodontists (n=305) and general dentists (n=191) regarding the significance, prevention and treatment of WSLs. All four groups indicated that WSLs did detract from the overall appearance of straight teeth. All four groups indicated that patients were the most responsible for the prevention of WSLs. All four groups indicated that the general dentist should be more responsible for the treatment of WSLs than the orthodontist. General dentists were significantly more likely to indicate that the orthodontist was most responsible for the prevention of WSLs (P <0.005).

The reported prevalence of decalcification in orthodontic patients varies from 2 to 96% mainly due to the lack of a standard examination technique. The aims of this study were: 1) to determine the prevalence of white spot lesions around brackets using visual examination and the DIAGNOdent; 2) to determine which teeth were the most susceptible to decalcification; and 3) to test the accuracy of the DIAGNOdent by comparing to the visual examination. The presence of white spot lesions was determined in two groups of patients who were 6 and 12 months into orthodontic treatment, respectively. The control group consisted of patients who were examined for white spot lesions immediately after having their braces placed on their teeth. The prevalence of white spot lesions was 38%, 46%, and 11% for the 6-month, 12-month, and control groups, respectively. There was a statistically significant correlation (r = 0.71) between the DIAGNOdent measurements and the visual examination.

Inledning: Forskning har visat att miljön där brott sker är avgörande för att förstå kriminalitetsmönster och dess koncentration i och till olika områden, även kallade hot spots. Socialekologisk teori ämnar förklara distributionen av kriminalitet i städer. Syftet med aktuell studie var dels att analysera vilka platser i en stad som har flest anmälningar för misshandelsbrott för individer över 18 år, dels att analysera polisarbetet i och anslutning till dessa platser i Uppsala innerstad under åren 2013 – 2015. I denna studie har Brottsmönsterteorin applicerats för att förklara resultatet. Metod: I denna studie tillämpades både kvalitativ och kvantitativ metod. Materialet som användes var polisregister för misshandelsbrott, dokument som beskriver polisens arbete samt en intervju. Anmälningarna från polisregistret fördes in i ArcGIS, ett datorprogram för visualisering av kartor, för att ta fram hot spots. Vidare analyserades polisens arbete på eller i nära anslutning till dessa platser. Resultat: I studien identifierades fyra hot spots. Resultatet visade att anmälningsfrekvensen hade minskat i två av fyra hot spots (hot spot 2 och 3). Det totala antalet misshandelsanmälningar i Uppsala innerstad hade minskat i förhållande befolkningsmängden i Uppsala kommun. Det problemorienterade polisarbetet fokuserade under treårsperioden på platser med hög alkoholkonsumtion och med en stor omsättning av människor. Slutsats: Kartläggning av olika typer av brott är effektivt för att arbeta brottspreventivt. För vissa typer av brott så som misshandel, kan det för polisen vara väl så effektivt att arbeta problemorienterat i hot spots såsom mot individer. / <p>2016-06-01</p>

Enamel damage and demineralisation are common complications associated with fixed orthodontic appliances. In particular, the clean-up of adhesive remnants after debonding is a recognised cause of enamel damage. Furthermore, fixed attachments offer retentive areas for accumulation of cariogenic bacteria leading to enamel demineralisation and formation of white spot lesions (WSLs). Bioactive glasses may be used to remove adhesives, preserving the integrity of the enamel surface, while also having the potential to induce enamel remineralisation, although their efficacy in both respects has received little attention. A systematic review evaluating the remineralisation potential of bioactive glasses was first undertaken. No prospective clinical studies were identified; however, a range of in vitro studies with heterogeneous designs were identified, largely providing encouraging results. A series of glasses was prepared with molar compositions similar to 45S5 (SylcTM; proprietary bioactive glass) but with constant fluoride, reduced silica and increased sodium and phosphate contents. These glasses were characterised in several tests and the most promising selected. This was designed with hardness lower than that of enamel and higher than orthodontic adhesives. Its effectiveness in terms of removal of composite- and glass ionomer- based orthodontic adhesives was evaluated against SylcTM and a tungsten carbide (TC) bur. This novel glass was subsequently used for remineralisation of artificially-induced orthodontic WSLs on extracted human teeth. The novel glass propelled via the air-abrasion system selectively removed adhesives without inducing tangible physical enamel damage compared to SylcTM and the conventional TC bur. It also remineralised WSLs with surface roughness and intensity of light backscattering similar to sound enamel. In addition, mineral deposits were detected on remineralised enamel surfaces; these acted as a protective layer on the enamel surface and improved its hardness. This layer was rich in calcium, phosphate, and fluoride; 19F MAS-NMR, confirmed the formation of fluorapatite. This is particularly beneficial since fluorapatite is more chemically stable than hydroxyapatite and has more resistance to acid attack. Hence, a promising bioactive glass has been developed.

Objectives: 1) To develop and investigate the bioactivities of a novel bioactive glass (BAG) composite designed as an orthodontic adhesive. 2) To investigate the preventive effect, and to test the bond strength of the adhesive. Methods: A novel, calcium and phosphate rich, and fluoride containing, bioactive glass (BAG) was prepared via the melt quench route and incorporated into an experimental resin to produce a light cured paste. The ratio of the resin to the powder was 20:80% respectively. The BAG powder was gradually replaced by a high fluoride and silica content glass (HSG) from 80%, to 60%, 50%, 40%, 25% and 0%. 90 disks (1.26mm thickness and 10mm diameter) were produced from each composition to be immersed in 3 solutions (demineralising artificial saliva pH=4 (AS4), remineralising artificial saliva pH=7 (AS7) and Tris buffer (TB) pH=7.3, 10 ml each. Measurements were taken at 10 time points (from 6 hours to 6 months) in 3 replicas in each solution. Ion release study was determined by ISE and ICP, and pH monitoring was conducted on the resulting solutions. Immersed disks were studied by FTIR, XRD, MAS-NMR and SEM for apatite formation. XMT were used to study the effects of this material on demineralisation/remineralisation in human enamel. Shear bond strength of the adhesive on bovine enamel were studied in different conditions using an Instron machine. Results: The pH increased with time for all the samples with BAG in all solutions and was linearly correlated to BAG loading. Ion release results revealed that the composite disks release up to 15ppm F-, 450ppm Ca2+ and 10ppm PO43- ions, and the release pattern is directly related to the immersion time, with the highest release found in AS4. FTIR spectra, XRD patterns and SEM images showed formation of apatite on all the BAG-resin disks, especially in AS4 and this increase with time. The MAS-NMR spectra indicated fluorapatite was also formed. The XMT studies showed that the novel material reduces demineralisation around the brackets by 80%. The shear bond strength of this novel material was comparable to that of Transbond XT. Conclusion: The novel BAG composites have significant long term releases of F-, Ca2+ and PO43- ions, especially in acidic conditions and form apatite (including FAP) in acidic and neutral solutions. This implies that the material has the potential as an orthodontic adhesive that can prevent white spot lesions around brackets.