Master of Science

thesisIntra-abdominal pressure (IAP) is the pressure within the abdominal cavity. IAP is routinely studied in the field of urogynecology to comprehend its relation to pelvic floor disorders. In contrast to the potential negative role of high IAP on the pelvic floor, IAP is important for various forms of human performance. Given the disparate thoughts on IAP and its impact on pelvic floor health and sport and exercise performance, better understanding the IAP response in women without pelvic floor disorders during physical activity is warranted. In brief, the purpose of the study was to describe IAP responses during a variety of exercises and physical activities in women without a history of pelvic floor disorders. Our primary aim is to calculate the percentage of maximal for a select group of the activities detailed in a previous study, using the IAP during seated ValSalva (VM) as the maximal capacity. A secondary aim is to characterize the relationship between the relative term of percent of maximal for each activity, and maximal IAP. We hypothesize that there will be an inverse relationship between percentage of maximal for each activity and maximal IAP. In total, the data of 55 women were included in the analysis. Women were aged 20-54 (M 30.38 ± SD 9.43 yrs) and had BMI values between 17.7-28.9 (M 22.4 ± SD 2.63 kg/m2). Participants completed a 1-hour exercise protocol in a human performance laboratory. Pearson r correlation results indicate that all relative values (% maximal of seated VM) were significantly and negatively correlated at (p < 0.001) with seated VM IAP, except for seated shoulder press with 6.9 kg (p 0.023) and 9.1 kg (p 0.557). Our findings support the contention that the IAP response to individual, submaximal activities exhibits a similar relationship to maximal capacity as that observed in well-established measures of fitness, such as muscular strength and oxygen consumption. It is imperative that coaches understand the relationship between IAP and higher intensity efforts during training. With this knowledge, strength and conditioning specialists may adjust training practices in order to limit the likelihood of precipitating pelvic floor symptoms in women

Field Strength and Monopoles in Dual U(1) Lattice Gauge Theory

In any Abelian gauge theory with an action periodic in the link variables one can perform a duality transformation not only in the partition function, but also in correlation functions including Polyakov loops. The calculation of expectation values in the confinement phase, like electric field strength or monopole currents in the presence of external charges, becomes significantly more efficient simulating the dual theory. We demonstrate this using the ordinary Wilson action. This approach also allows a quantitative analysis of the dual superconductor model, because the dual transformed U(1) theory can be regarded as limit of a dual non-compact Abelian Higgs model. In this way we also try to interpret the behaviour of monopole condensate and string fluctuations. Finally we present some applications for simulating the dual U(1) gauge theory.Comment: Talk presented at LATTICE96(topology) ; 3 pages, latex, 4 figures; complete postscript file also available at ftp://is1.kph.tuwien.ac.at/pub/zach/stl96.ps.g

Rhizomes and Diffusions for Processing Highly Skewed Graphs on Fine-Grain Message-Driven Systems

The paper provides a unified co-design of 1) a programming and execution model that allows spawning tasks from within the vertex data at runtime, 2) language constructs for \textit{actions} that send work to where the data resides, combining parallel expressiveness of local control objects (LCOs) to implement asynchronous graph processing primitives, 3) and an innovative vertex-centric data-structure, using the concept of Rhizomes, that parallelizes both the out and in-degree load of vertex objects across many cores and yet provides a single programming abstraction to the vertex objects. The data structure hierarchically parallelizes the out-degree load of vertices and the in-degree load laterally. The rhizomes internally communicate and remain consistent, using event-driven synchronization mechanisms, to provide a unified and correct view of the vertex. Simulated experimental results show performance gains for BFS, SSSP, and Page Rank on large chip sizes for the tested input graph datasets containing highly skewed degree distribution. The improvements come from the ability to express and create fine-grain dynamic computing task in the form of \textit{actions}, language constructs that aid the compiler to generate code that the runtime system uses to optimally schedule tasks, and the data structure that shares both in and out-degree compute workload among memory-processing elements.Comment: arXiv admin note: text overlap with arXiv:2402.0257

Critical Radius of Insulation

The critical radius of insulation is a counterintuitive concept within the study of heat transfer. The theory states that adding insulation to a cylindrical or spherical object will increase the rate of heat loss rather than decrease it, if the radius (thickness) of the insulation is at its “critical” value. The Critical Radius of Insulation Senior Project is designed to demonstrate this phenomenon to Heat Transfer students via a portable apparatus. The concept will be demonstrated with a cylindrical object which is heated by way of a separate voltage source. Thermocouples will display the temperature of the cylinder while insulation is added along with ambient air temperature, showing a distinct decrease in temperature caused by the addition of insulation. The design team conducted preliminary experiments using 1Ω, 2Ω, and 10Ω power resistors in an attempt to demonstrate the critical radius theory and evaluate the viability of using power resistors as the heated cylinder. The experiments were unsuccessful in demonstrating the critical radius theory but showed that the prototype setup was a viable design that could demonstrate this theory if the insulation material, insulation thickness, and power resistor diameter were properly modified. Based on the preliminary testing and analysis, a conceptual prototype model was developed. After further testing, the team determined that power resistors would take too long to reach steady state temperatures for a short classroom demonstration and that the diameters of the resistors were too large to demonstrate this theory with the appropriate experimental margin. Other studies were conducted using different heated cylinders starting with Calrod® heating elements. Testing was conducted with these heaters and 3D printed PLA insulation with great success. The heat loss for this setup was greater with the insulation than without, so the team used this heater and insulation combination to create a functioning structural prototype. Once the structural prototype was constructed and thoroughly tested, the team was able to successfully create a portable demonstration apparatus that physically shows the critical radius of insulation theory at work. This document details the iterative design process used to achieve the final design, the final design description, the manufacturing process used to build the final design, the verification and testing process, and conclusions about the overall project and the teams experience. The team’s overall objectives for this project are to first understand the concept of the critical radius of insulation and the experimental variables and assumptions that are important to proving it. The next step is to design and build an apparatus that can be used as a classroom demonstration and test this apparatus to ensure it is safe, easy to use, and clearly demonstrates critical radius theory. A supplemental handout also needs to be created to simply describe the theory to Heat Transfer students that will be witnessing this demonstration

Sustainability, systems thinking and professional practice

This article explores the impact of the new sustainability agenda on the occupational and professional needs of those who have taken educational and training programmes in the environmental field either at undergraduate or postgraduate level or through relevant professional institutions' continuing professional development programmes. It also describes a one-day workshop for the professionals on sustainable development, based on systems thinking and practice. The workshop provides a model for developing greater understanding and effective action in professional practice, by using dialogue and interprofessional learning to explore approaches to sustainability in a variety of business and professional contexts. It introduces the principles underpinning the concept of sustainability and provides tools to support the integration of sustainable development into professional practice and organisational change

A functional evaluation of feeding in the surgeonfish Ctenochaetus striatus: the role of soft tissues

Ctenochaetus striatus is one of the most abundant surgeonfishes on Indo-Pacific coral reefs, yet the functional role and feeding ecology of this species remain unclear. This species is reported to possess a rigid structure in its palate that is used for scraping, but some authors have reported that this element is comprised of soft tissue. To resolve the nature and role of this structure in the feeding ecology of C. striatus we examined evidence from anatomical observations, scanning electron microscopy, histology, X-ray micro-computed tomography scanning, highspeed video and field observations. We found that C. striatus from the Great Barrier Reef possess a retention plate (RP) on their palates immediately posterior to the premaxillary teeth which is soft, covered in a thin veneer of keratin with a papillate surface. This RP appears to be used during feeding, but does not appear to be responsible for the removal of material, which is achieved primarily by a fast closure of the lower jaw. We infer that the RP acts primarily as a 'dustpan', in a 'dustpan and brush' feeding mechanism, to facilitate the collection of particulate material from algal turfs

Flux tubes and their interaction in U(1) lattice gauge theory

We investigate singly and doubly charged flux tubes in U(1) lattice gauge theory. By simulating the dually transformed path integral we are able to consider large flux tube lengths, low temperatures, and multiply charged systems without loss of numerical precision. We simulate flux tubes between static sources as well as periodically closed flux tubes, calculating flux tube profiles, the total field energy and the free energy. Our main results are that the string tension in both three and four dimensions scales proportionally to the charge -- which is in contrast to previous lattice results -- and that in four-dimensional U(1) there is an attractive interaction between flux tubes for beta approaching the phase transition.Comment: 19 pages, latex2e with tex- and eps-figures; complete postscript file also available at ftp://is1.kph.tuwien.ac.at/pub/zach/np97.ps.g

Cortical gray and subcortical white matter associations in Parkinson's disease

Cortical atrophy has been documented in both Parkinson’s disease (PD) and healthy aging, but its relationship to changes in subcortical white matter is unknown. This was investigated by obtaining T1- and diffusion-weighted images from 76 PD and 70 controls at baseline, 18-, and 36-months, from which cortical volumes and underlying subcortical white matter axial (AD), radial (RD) diffusivities, and fractional anisotropy (FA) were determined. Twelve of 69 cortical subregions had significant group differences, and for these underlying subcortical white matter was explored. At baseline, higher cortical volumes were significantly correlated with lower underlying subcortical white matter AD, RD, and higher FA (Ps ≤0.017) in PD. Longitudinally, higher rates of cortical atrophy in PD were associated with increased rates of change in AD RD, and FA values (Ps ≤ 0.0013) in two subregions explored. The significant gray-white matter associations were not found in controls. Thus, unlike healthy aging, cortical atrophy and subcortical white matter changes may not be independent events in PD

Stage-dependent loss of cortical gyrification as Parkinson disease “unfolds”

Nigrostriatal terminal losses are known to progress most rapidly in early-stage Parkinson disease (PD) and then plateau, whereas cortical pathology continues and may provide a better marker of PD progression in later stages. We investigated cortical gyrification indices in patients with different durations of PD, since cortical folding may capture complex processes involving transverse forces of neuronal sheets or underlying axonal connectivity. Longitudinal cohort structural MRI were obtained at baseline, 18 months, and 36 months from 70 patients with PD without dementia and 70 control participants. Cortical local gyrification index (LGI) was compared between controls and PD subgroups based upon duration of illness (DOI, 5 years [PDL, n = 24]) and adjusted using false discovery rate. Associations between LGI and clinical measurements were assessed using multiple linear regression. Areas having significantly reduced LGI also were analyzed using baseline data from a newly established cohort (PD n = 87, control n = 66) to validate our findings. In the longitudinal cohort, PDL had significantly reduced overall gyrification, and bilaterally in the inferior parietal, postcentral, precentral, superior frontal, and supramarginal areas, compared to controls (p < 0.05). Longitudinally, loss of gyrification was accelerated in PDM participants, compared to controls. LGI showed robust correlations with DOI and also was correlated with PD-related clinical measurements. Similar results were obtained in the validation sample. Loss of cortical gyrification may be accelerated within the first few years after PD diagnosis, and become particularly prominent in later stages. Thus, it may provide a metric for monitoring progression in vivo