Permeability evolution during progressive development of deformation bands in porous sandstones

[1] Triaxial deformation experiments were carried out on large (0.1 m) diameter cores of a porous sandstone in order to investigate the evolution of bulk sample permeability as a function of axial strain and effective confining pressure. The log permeability of each sample evolved via three stages: (1) a linear decrease prior to sample failure associated with poroelastic compaction, (2) a transient increase associated with dynamic stress drop, and (3) a systematic quasi-static decrease associated with progressive formation of new deformation bands with increasing inelastic axial strain. A quantitative model for permeability evolution with increasing inelastic axial strain is used to analyze the permeability data in the postfailure stage. The model explicitly accounts for the observed fault zone geometry, allowing the permeability of individual deformation bands to be estimated from measured bulk parameters. In a test of the model for Clashach sandstone, the parameters vary systematically with confining pressure and define a simple constitutive rule for bulk permeability of the sample as a function of inelastic axial strain and effective confining pressure. The parameters may thus be useful in predicting fault permeability and sealing potential as a function of burial depth and faul

Financial Accounting 3B

Exam paper for second semester: Financial Accounting 3

"In Our Own Words" : Gendered narratives of Lesbian, Gay, Bisexual and Transgender (LGBTI's) middle-aged adults

Storytelling collection of same-sex partner

Guiding Brain Tumor Resection Using Surface-Enhanced Raman Scattering Nanoparticles and a Hand-Held Raman Scanner

The current difficulty in visualizing the true extent of malignant brain tumors during surgical resection represents one of the major reasons for the poor prognosis of brain tumor patients. Here, we evaluated the ability of a hand-held Raman scanner, guided by surface-enhanced Raman scattering (SERS) nanoparticles, to identify the microscopic tumor extent in a genetically engineered RCAS/tv-a glioblastoma mouse model. In a simulated intraoperative scenario, we tested both a static Raman imaging device and a mobile, hand-held Raman scanner. We show that SERS image-guided resection is more accurate than resection using white light visualization alone. Both methods complemented each other, and correlation with histology showed that SERS nanoparticles accurately outlined the extent of the tumors. Importantly, the hand-held Raman probe not only allowed near real-time scanning, but also detected additional microscopic foci of cancer in the resection bed that were not seen on static SERS images and would otherwise have been missed. This technology has a strong potential for clinical translation because it uses inert gold-silica SERS nanoparticles and a hand-held Raman scanner that can guide brain tumor resection in the operating room

Prevalence of adolescent obesity at a high school in the City of Tshwane

Background: Obesity has been reported to be on the rise in the world and South Africa is no exception. In recent years obesity has been reported to contribute to the increasing number of people with hypertension and diabetes mellitus. Africa has the fastest growing number of overweight and obese adolescents, with indications that in 2010, it had more than doubled since 1990. Some people might perceive being overweight as being round and healthy which might contribute to the increased rate of obesity in South Africa. Physical and psychological changes that occur during adolescence can also be observed earlier during the preteen years (ages 9–12 years). During this time, peer groups and external appearance are of importance. Physical changes, such as obesity, might be perceived negatively by adolescents, affecting their self-esteem. Objectives: The purpose of the study was to determine the prevalence of adolescent obesity at a high school in the City of Tshwane. Method: A cross-sectional survey was conducted. Stratified random sampling was used and data were collected from 30% of the total population as recommended by the statistician. Data analysis was performed using descriptive analysis. Validity and reliability were ensured through calibrating the weight-monitoring scale and the measuring tape, which are collection tools. Results: The results identified the prevalence of adolescent obesity at 8.57%. There is evidence of abdominal obesity and waist–hip ratio ≥ 1. The results show that there is a steady increase in obesity levels among adolescents. The poor response of parents was observed and could demonstrate the need to form stronger partnerships for weight reduction interventions. Conclusion: Evidence-based prevalence allowed for conceptualisation of the scope of the obesity epidemic and how children and young people are also affected. To enable proper planning for adolescent obesity interventions, the depth of consequences of obesity for the adolescent cohort should be well defined and clarified

Behavioural and socio-ecological factors that influence access and utilisation of health services by young people living in rural KwaZulu-Natal, South Africa: Implications for intervention.

BACKGROUND: Young people's health service utilisation (the number accessing a facility) has been the focus of guidelines and health systems strengthening policies. This is due to young people being at an increased health risk because of inequitable access and utilisation of health services, which is more pronounced in rural settings with limited service availability. This is a major concern as globally, youth constitute a considerable and increasing part of the population in Sub-Saharan Africa. OBJECTIVE: The objective of this paper is to present a comprehensive approach for the exploration of health service utilisation by young people in rural KwaZulu-Natal, South Africa. We examined barriers and facilitators conceptualised by the constructs of the Theory of Planned Behaviour, framed within a socio-ecological model. METHODS: Data were collected in January to June 2017 from two sites using in-depth interviews, spiral transect walks and community mapping with young people (aged 10 to 24 years), primary care health providers, school health professionals, community stakeholders and young people's parents. RESULTS: Socio-ecological and behavioural factors influenced young people's intention to use services. Barriers included perceived negative attitudes of health providers and perceived poor staff competencies. Facilitators included an appreciation of receiving health education and assumed improved health. At social and community levels, normative beliefs hindered young people from utilising services as they feared stigmatisation and gossip. At a public policy level, structural elements had a disempowering effect as the physical layout of the clinics hindered utilisation, limited resources influenced staffing, and facility opening times were not convenient for school goers. CONCLUSION: We suggest that to fully appreciate the complexity of health service utilisation, it is necessary to not only consider factors and processes relevant to the individual, but also acknowledge and act upon, the disjuncture between community level cultural values, norms and national policies