Dynamics of downdruaghts and cold pools: an experimental and numerical study

Downward moving cold air within a thunderstorm, known as a downdraught, can be an additional storm hazard, and also prolong the convective lifecycle. An understanding of downdraughts is therefore useful for weather forecasting. Typically, in weather forecasting downdraughts are modelled using the theory of a plume from Morton et al. (1956), which inherently assumes that the plume is long and thin. However, downdraughts are often wider than their height and hence deviate from the Morton, Taylor and Turner theory. More recently they have been compared to thermals rather than plumes, and their flow along the ground after impact as axisymmetric gravity currents, for example in the study performed by Rooney (2015). In this thesis both numerical and laboratory experiments have been performed by releasing finite volumes of dense fluid from cylinders of varying lengths. In the laboratory the cylinders were perspex tubes submerged in a tank filled with sodium chloride at a fixed height above the base of the tank. The tubes were sealed at the base using a latex sheet and filled with sodium nitrate solution which was dyed using methylene blue. The fluid was released by bursting the latex sheet and was analysed using an extension to the dye attenuation technique developed by Cenedese & Dalziel (1998). Red, green and blue LEDs were used to address the need for a larger range of dye concentration than provided by red LEDs alone. The numerical experiments were performed in MONC, the Met Office’s large eddy model. Some basic testing of the model, and comparison with Rooney (2015) was done to determine the set up needed to best reproduce both Rooney (2015) and the laboratory experiments. Edge detection and tracking was used for both sets of experiments to see how the vertical and radial velocities, and shape of the releases change when changing both the length of the cylinder, and height of the cylinder from the ground. Velocities and shape information from edge detection, and information on the volume from dye attenuation was also used to give information on the entrainment of the thermals. Changing the height and length of the tube determined whether or not the dense release had developed into a self-similar thermal, was still draining from the tube, or transitioning between the two, upon impact with the ground. It was found that the slumping phases and heights of the resulting gravity currents behave differently depending on both the height and length of the tube. Theory for the evolution of the flow during the draining of the tube was developed and compared to both the numerical and laboratory experiments. This model combined with existing thermal theory has been used to define more realistic initial conditions for a gravity current model

Sagittal Subtalar and Talocrural Joint Assessment During Ambulation With Controlled Ankle Movement (CAM) Boots

Background: The purpose of the current study was to determine sagittal plane talocrural and subtalar kinematic differences between barefoot and controlled ankle movement (CAM) boot walking. This study used fluoroscopic images to determine talar motion relative to tibia and calcaneal motion relative to talus. Methods: Fourteen male subjects (mean age 24.1 ± 3.5 years) screened for normal gait were tested. A fluoroscopy unit was used to collect images at 200 Hz during stance. Sagittal motion of the talocrural and subtalar joints were analyzed barefoot and within short and tall CAM boots. Results: Barefoot talocrural mean maximum plantar and dorsiflexion were 9.2 ± 5.4 degrees and −7.5 ± 7.4 degrees, respectively; short CAM boot mean maximum plantar and dorsiflexion were 3.2 ± 4.0 degrees and −4.8 ± 10.2 degrees, respectively; and tall CAM boot mean maximum plantar and dorsiflexion were −0.2 ± 3.5 degrees and −2.4 ± 5.1 degrees, respectively. Talocrural mean range of motion (ROM) decreased from barefoot (16.7 ± 5.1 degrees) to short CAM boot (8.0 ± 4.9 degrees) to tall CAM boot (2.2 ± 2.5 degrees). Subtalar mean maximum plantarflexion angles were 5.3 ± 5.6 degrees for barefoot walking, 4.1 ± 5.9 degrees for short CAM boot walking, and 3.0 ± 4.7 degrees for tall CAM boot walking. Mean minimum subtalar plantarflexion angles were 0.7 ± 3.2 degrees for barefoot walking, 0.7 ± 2.9 degrees for short CAM boot walking, and 0.1 ± 4.8 degrees for tall CAM boot walking. Subtalar mean ROM decreased from barefoot (4.6 ± 3.9 degrees) to short CAM boot (3.4 ± 3.8 degrees) to tall CAM boot (2.9 ± 2.6 degrees). Conclusion: Tall and short CAM boot intervention was shown to limit both talocrural and subtalar motion in the sagittal plane during ambulation. The greatest reductions were seen with the tall CAM boot, which limited talocrural motion by 86.8% and subtalar motion by 37.0% compared to barefoot. Short CAM boot intervention reduced talocrural motion by 52.1% and subtalar motion by 26.1% compared to barefoot. Clinical Relevance: Both short and tall CAM boots reduced talocrural and subtalar motion during gait. The short CAM boot was more convenient to use, whereas the tall CAM boot more effectively reduced motion. In treatments requiring greater immobilization of the talocrural and subtalar joints, the tall CAM boot should be considered

Solution Focused Financial Therapy: A Brief Report of a Pilot Study

The financial counseling, financial planning, and financial therapy fields are hampered by a conceptual and empirical paucity of clinical and experimental evidence-based research. In an attempt to decrease this gap in the literature, a pilot study was developed to test the implementation of a solution-focused financial therapy client intervention approach, in which solution-focused therapy techniques were applied in a financial counseling setting. This paper reports findings from a clinical intervention study of college students (N = 8) who presented a variety of financial issues related to budgeting, investing, and debt repayment problems. Data were gathered prior to the start of treatment, after treatment ended, and three months later. Participants’ psychological well-being and financial behaviors improved, while financial distress decreased. The solution-focused financial therapy approach used is discussed

Solution Focused Financial Therapy: A Brief Report of a Pilot Study

The financial counseling, financial planning, and financial therapy fields are hampered by a conceptual and empirical paucity of clinical and experimental evidence-based research. In an attempt to decrease this gap in the literature, a pilot study was developed to test the implementation of a solution-focused financial therapy client intervention approach, in which solution-focused therapy techniques were applied in a financial counseling setting. This paper reports findings from a clinical intervention study of college students (N = 8) who presented a variety of financial issues related to budgeting, investing, and debt repayment problems. Data were gathered prior to the start of treatment, after treatment ended, and three months later. Participants’ psychological well-being and financial behaviors improved, while financial distress decreased. The solution-focused financial therapy approach used is discussed

TOM40 Mediates Mitochondrial Dysfunction Induced by α-Synuclein Accumulation in Parkinson's Disease.

Alpha-synuclein (α-Syn) accumulation/aggregation and mitochondrial dysfunction play prominent roles in the pathology of Parkinson's disease. We have previously shown that postmortem human dopaminergic neurons from PD brains accumulate high levels of mitochondrial DNA (mtDNA) deletions. We now addressed the question, whether alterations in a component of the mitochondrial import machinery -TOM40- might contribute to the mitochondrial dysfunction and damage in PD. For this purpose, we studied levels of TOM40, mtDNA deletions, oxidative damage, energy production, and complexes of the respiratory chain in brain homogenates as well as in single neurons, using laser-capture-microdissection in transgenic mice overexpressing human wildtype α-Syn. Additionally, we used lentivirus-mediated stereotactic delivery of a component of this import machinery into mouse brain as a novel therapeutic strategy. We report here that TOM40 is significantly reduced in the brain of PD patients and in α-Syn transgenic mice. TOM40 deficits were associated with increased mtDNA deletions and oxidative DNA damage, and with decreased energy production and altered levels of complex I proteins in α-Syn transgenic mice. Lentiviral-mediated overexpression of Tom40 in α-Syn-transgenic mice brains ameliorated energy deficits as well as oxidative burden. Our results suggest that alterations in the mitochondrial protein transport machinery might contribute to mitochondrial impairment in α-Synucleinopathies

The environmental profile of a community’s health: a cross-sectional study on tobacco marketing in 16 countries.

OBJECTIVE: To examine and compare tobacco marketing in 16 countries while the Framework Convention on Tobacco Control requires parties to implement a comprehensive ban on such marketing. METHODS: Between 2009 and 2012, a kilometre-long walk was completed by trained investigators in 462 communities across 16 countries to collect data on tobacco marketing. We interviewed community members about their exposure to traditional and non-traditional marketing in the previous six months. To examine differences in marketing between urban and rural communities and between high-, middle- and low-income countries, we used multilevel regression models controlling for potential confounders. FINDINGS: Compared with high-income countries, the number of tobacco advertisements observed was 81 times higher in low-income countries (incidence rate ratio, IRR: 80.98; 95% confidence interval, CI: 4.15-1578.42) and the number of tobacco outlets was 2.5 times higher in both low- and lower-middle-income countries (IRR: 2.58; 95% CI: 1.17-5.67 and IRR: 2.52; CI: 1.23-5.17, respectively). Of the 11,842 interviewees, 1184 (10%) reported seeing at least five types of tobacco marketing. Self-reported exposure to at least one type of traditional marketing was 10 times higher in low-income countries than in high-income countries (odds ratio, OR: 9.77; 95% CI: 1.24-76.77). For almost all measures, marketing exposure was significantly lower in the rural communities than in the urban communities. CONCLUSION: Despite global legislation to limit tobacco marketing, it appears ubiquitous. The frequency and type of tobacco marketing varies on the national level by income group and by community type, appearing to be greatest in low-income countries and urban communities

The environmental profile of a community's health: a cross-sectional study on tobacco marketing in 16 countries.

OBJECTIVE: To examine and compare tobacco marketing in 16 countries while the Framework Convention on Tobacco Control requires parties to implement a comprehensive ban on such marketing. METHODS: Between 2009 and 2012, a kilometre-long walk was completed by trained investigators in 462 communities across 16 countries to collect data on tobacco marketing. We interviewed community members about their exposure to traditional and non-traditional marketing in the previous six months. To examine differences in marketing between urban and rural communities and between high-, middle- and low-income countries, we used multilevel regression models controlling for potential confounders. FINDINGS: Compared with high-income countries, the number of tobacco advertisements observed was 81 times higher in low-income countries (incidence rate ratio, IRR: 80.98; 95% confidence interval, CI: 4.15-1578.42) and the number of tobacco outlets was 2.5 times higher in both low- and lower-middle-income countries (IRR: 2.58; 95% CI: 1.17-5.67 and IRR: 2.52; CI: 1.23-5.17, respectively). Of the 11,842 interviewees, 1184 (10%) reported seeing at least five types of tobacco marketing. Self-reported exposure to at least one type of traditional marketing was 10 times higher in low-income countries than in high-income countries (odds ratio, OR: 9.77; 95% CI: 1.24-76.77). For almost all measures, marketing exposure was significantly lower in the rural communities than in the urban communities. CONCLUSION: Despite global legislation to limit tobacco marketing, it appears ubiquitous. The frequency and type of tobacco marketing varies on the national level by income group and by community type, appearing to be greatest in low-income countries and urban communities

DU Undergraduate Showcase: Research, Scholarship, and Creative Works

DU Undergraduate Showcase: Research, Scholarship, and Creative Work