The Heart of a Horse: 3‐D Echocardiographic Analysis of the Equine Aortic Valve

Aortic regurgitation (AR) can be a normal function of aging or a disease in younger horses. Symptoms range from no outward signs to decreased performance to sudden cardiac arrest. My study used 3‐D echocardiography, ultrasound of the heart, to look at the equine aortic valve and assess it for AR severity. Three‐dimensional echocardiography records a pyramid of tissue rather than a 2‐D plane, showing cardiac structures difficult to visualize in standard 2‐D methods. In normal valves, only the edges of the cusps were visible, as the tissue is very thin when images were taken from the right, which is standard positioning for imaging the aortic valve. I observed the cusps of the aortic valve to be thickened in horses with AR, with degree of thickening corresponding to AR severity. Left‐sided images were generally worse quality than right‐sided, but in some cases there was better visualization of some aspects of the aortic valve in left‐sided images. 3‐D echocardiography potentially could be used as a standard for diagnosis of AR, specifically by looking at cusp thicknesses, and could more specifically diagnose which part of the valve is affected by disease

Colorado Baby Boomers: Challenges and Opportunities

This look at Colorado's 55- to 65-year-old population provides insights into how senior-serving organizations and agencies can better plan, prepare and address the needs of the growing number of Coloradans approaching retirement. This sizeable group - nearly half a million strong - offers unique opportunities to communities, employers and charities through their considerable knowledge, skills and enthusiasm. At the same time, there are significant challenges that require change and adaptation to provide aging boomers with adequate health care and coverage, employment, education and service opportunities

The causes and effects of depreciation in office buildings: a ten year update

This paper publishes the results of the 1996 study, which repeats a cross-section analysis of around 125 City of London office buildings, and examines the longitudinal data contributed by a sample of 56 unrefurbished properties common to the 1986 and 1996 City of London datasets. An estimate of the average rate of rental and capital value depreciation is made; the effect of age is shown not to be straight-line; and the causes if depreciation are measured. The results are compared with the 1986 City of London findings

Health literacy practices in social virtual worlds and the influence on health behaviour

This study explored how health information accessed via a 3D social virtual world and the representation of ‘self’ through the use of an avatar impact physical world health behaviour. In-depth interviews were conducted in a sample of 25 people, across 10 countries, who accessed health information in a virtual world (VW): 12 females and 13 males. Interviews were audio-recorded via private in-world voice chat or via private instant message. Thematic analysis was used to analyse the data. The social skills and practices evidenced demonstrate how the collective knowledge and skills of communities in VWs can influence improvements in individual and community health literacy through a distributed model. The findings offer support for moving away from the idea of health literacy as a set of skills which reside within an individual to a sociocultural model of health literacy. Social VWs can offer a place where people can access health information in multiple formats through the use of an avatar, which can influence changes in behaviour in the physical world and the VW. This can lead to an improvement in social skills and health literacy practices and represents a social model of health literacy

Digital Hologram Image Processing

In this thesis we discuss and examine the contributions we have made to the field of digital hologram image processing. In particular, we will deal with the processing of numerical reconstructions of real-world three-dimensional macroscopic objects recorded by in-line digital holography. Our selection of in-line digital holography over off-axis digital holography is based primarily on resolution. There is evidence that an off-axis architecture requires approximately four times the resolution to record a hologram than an in-line architecture. The high resolution of holographic film means this is acceptable in optical holography. However, in digital holography the bandwidth of the recording medium is already severely limited and if we are to extract information from reconstructions we need the highest possible resolution which, if one cannot harness the functionality of accurately reconstructing phase, is achieved through using an in-line architecture. Two of the most significant problems encountered with reconstructions of in-line digital holograms include the small depth-of-field of each reconstruction and corruptive influence of the unwanted twin-image. This small depth-of-field makes it difficult to accurately process the numerical reconstructions and it is in this shortcoming that we will make our first three contributions: focusing algorithms, background and object segmentation algorithms and algorithms to create a single image where all object regions are in focus. Using a combination of our focusing algorithms and our background segmentation algorithm, we will make our fourth contribution: a rapid twin-image reduction algorithm for in-line digital holography. We believe that our techniques would be applicable to all digital holographic objects, in particular its relevant to objects where phase unwrapping is not an option. We demonstrate the usefulness of the algorithms for a range of macroscopic objects with varying texture and contrast

Next Spring

Beck sat still. It is possible to shut someone out. It\u27s got to be..

A w-band quasi-optical mode converter and gyro-BWO experiment

High power coherent microwave sources at shorter wavelengths (mm and sub-mm) are in great demand, especially in the fields of plasma physics, remote sensing and imaging and for electron spin resonance spectroscopy. Gyro-devices are by their nature particularly suited to this type of application due to the fast-wave cyclotron resonance maser instability, which is capable of producing high power radiation at frequencies that prove challenging for other sources. A W-band gyro-device based on a cusp electron beam source with a helically corrugated interaction region is currently under development to provide a continuously tuneable source over the range between 90 GHz to 100 GHz with a CW power output of ~10 kW. The work presented herein encompasses the design, construction and measurement of a prototype output launcher for this gyro-device. A corrugated mode converting horn was designed to act as a quasi-optical mode converter that converts the fundamental operating mode within the gyro-TWA (TE11) to a hybrid mode, which is closely coupled to the fundamental free space Gaussian mode (TEM00). This free space mode allows the possibility for the inclusion of an energy recovery system that can recover a percentage of the energy from the spent electron beam and is predicted to increase overall efficiency by up to 40%. For this scheme the electron beam must be decoupled from the radiation, which can pass through the collector system and vacuum window unperturbed while the electrons are collected at the energy recovery system. This type of corrugated mode converting horn was chosen due to the advantages of a greater bandwidth and the capability to provide a source that is continuously tuneable over this bandwidth. The results of the design and integration of this corrugated mode converting horn with the gyro-device are presented. The prototype operates over a continuously tuneable bandwidth of 90 to 100 GHz with a return loss better than -35 dB and a Gaussian coupling efficiency of 97.8%. The far field radiation pattern shows a highly symmetrical structure with 99.9% of the power radiated within a cone with a half angle of less than 19° and a cross-polar level less than -40 dB.High power coherent microwave sources at shorter wavelengths (mm and sub-mm) are in great demand, especially in the fields of plasma physics, remote sensing and imaging and for electron spin resonance spectroscopy. Gyro-devices are by their nature particularly suited to this type of application due to the fast-wave cyclotron resonance maser instability, which is capable of producing high power radiation at frequencies that prove challenging for other sources. A W-band gyro-device based on a cusp electron beam source with a helically corrugated interaction region is currently under development to provide a continuously tuneable source over the range between 90 GHz to 100 GHz with a CW power output of ~10 kW. The work presented herein encompasses the design, construction and measurement of a prototype output launcher for this gyro-device. A corrugated mode converting horn was designed to act as a quasi-optical mode converter that converts the fundamental operating mode within the gyro-TWA (TE11) to a hybrid mode, which is closely coupled to the fundamental free space Gaussian mode (TEM00). This free space mode allows the possibility for the inclusion of an energy recovery system that can recover a percentage of the energy from the spent electron beam and is predicted to increase overall efficiency by up to 40%. For this scheme the electron beam must be decoupled from the radiation, which can pass through the collector system and vacuum window unperturbed while the electrons are collected at the energy recovery system. This type of corrugated mode converting horn was chosen due to the advantages of a greater bandwidth and the capability to provide a source that is continuously tuneable over this bandwidth. The results of the design and integration of this corrugated mode converting horn with the gyro-device are presented. The prototype operates over a continuously tuneable bandwidth of 90 to 100 GHz with a return loss better than -35 dB and a Gaussian coupling efficiency of 97.8%. The far field radiation pattern shows a highly symmetrical structure with 99.9% of the power radiated within a cone with a half angle of less than 19° and a cross-polar level less than -40 dB

Ecological Considerations and Application of Urban Tree Selection in Massachusetts

Trees provide countless environmental, economic, and societal benefits to the urban environment, and may become increasingly important to maintaining environmental quality and human well-being in the face of increasing urbanization and climate change. However, trees in these urban areas are rapidly diminishing across the United States. Much of this loss can be prevented with proper planning and management, focused on selecting tree species that are both well-suited to the area’s growing conditions and able to survive the many stress factors in an urban setting. Choosing which tree species to plant in Massachusetts is especially challenging considering the lack of resources specific to the state’s growing conditions and the urban environment. I conduct a literature review to answer two research questions: (1) What ecological considerations should be made before tree selection, and (2) Which species should be planted in the urban environments of Massachusetts. My results yielded a comprehensive guide, in book form, detailing the five ecological considerations I recommend to make before selection, and profiles of 75 tree species recommended to plant in these areas. This book may act as a resource for tree wardens and homeowners to help choose the best species for their specific planting site, prompt other states to create or update their own state-specific selection guide, and encourage tree nurseries to grow and distribute favorable species, ultimately providing their communities with the benefits that trees provide

Three-Dimensional Echocardiographic Analysis of the Equine Aortic Valve

This research focused on 3D echocardiography of the aortic valve (AV) in horses. Aortic regurgitation (AR) can be a common finding in older horses, and in severe cases can result in decreased performance and even sudden cardiac death. Standard AR diagnosis includes 2D echocardiography from the right side of the horse. Three-dimensional echocardiography (3DE) records a pyramid of tissue, showing structures in the heart difficult to visualize in 2D methods, and can be more accurate as it does not rely as heavily on placement of the transducer. Nine images of normal AV’s were assessed, and still frames of anatomical structures were obtained. Area and circumference from the enface view, and diameter and cusp thicknesses from side and enface views were measured. These measurements were also taken on images from 5 horses with mild, 7 with moderate, and 2 with severe AR. 3DE images from the left side of 9 normal horses were taken for comparison. In normal valves, the edges of the cusps were visible but the centers were not from the right. The left coronary cusp was generally most visible from the right sided view. The cusp edges and lunulae of the aortic valve were thickened in horses with AR, with degree of thickening corresponding to AR severity. The center of the cusps appeared opaque in some horses with AR. There was a statistically significant positive correlation between thickness of the left coronary cusp and AR severity. Left sided images were generally of worse quality than those from the right, but in some cases there was better visualization of the right and noncoronary cusps. 3DE could potentially be used as a standard for diagnosis of AR, specifically by looking at cusp thicknesses, and could more specifically diagnose which part of the valve is affected by disease

Digital Hologram Image Processing

In this thesis we discuss and examine the contributions we have made to the field of digital hologram image processing. In particular, we will deal with the processing of numerical reconstructions of real-world three-dimensional macroscopic objects recorded by in-line digital holography. Our selection of in-line digital holography over off-axis digital holography is based primarily on resolution. There is evidence that an off-axis architecture requires approximately four times the resolution to record a hologram than an in-line architecture. The high resolution of holographic film means this is acceptable in optical holography. However, in digital holography the bandwidth of the recording medium is already severely limited and if we are to extract information from reconstructions we need the highest possible resolution which, if one cannot harness the functionality of accurately reconstructing phase, is achieved through using an in-line architecture. Two of the most significant problems encountered with reconstructions of in-line digital holograms include the small depth-of-field of each reconstruction and corruptive influence of the unwanted twin-image. This small depth-of-field makes it difficult to accurately process the numerical reconstructions and it is in this shortcoming that we will make our first three contributions: focusing algorithms, background and object segmentation algorithms and algorithms to create a single image where all object regions are in focus. Using a combination of our focusing algorithms and our background segmentation algorithm, we will make our fourth contribution: a rapid twin-image reduction algorithm for in-line digital holography. We believe that our techniques would be applicable to all digital holographic objects, in particular its relevant to objects where phase unwrapping is not an option. We demonstrate the usefulness of the algorithms for a range of macroscopic objects with varying texture and contrast