A search for TeV gamma ray emission from X-ray binary stars

This work is concerned with the detection of pulsed TeV gamma ray emission from a number of X-ray binary systems by the use of the atmospheric Cerenkov technique. Chapters 1 and 2 give an overview of the development of gamma ray astronomy, with emphasis placed on progress made in the detection of TeV gamma rays by their Cerenkov radiation in the atmosphere. Chapters 3 and 4 describe the University of Durham atmospheric Cerenkov telescopes, which were used to make the observations reported in this work, and the standard data processing and analysis procedures adopted. The main part of the thesis deals with the application of these techniques to observations of five X-ray binaries. After a review of the properties of such objects in Chapter 5, Chapters 6 and 7 deal specifically with the results for two of the systems considered to be among the most likely candidates to give a detectable TeV photon flux; Centaurus X-3 and Vela X-1. A study of all data recorded on Cen X-3 over the course of six years suggests the presence of a weak gamma ray flux pulsed at the X-ray period. Previous reports of stronger emission near the ascending node of the orbit are confirmed here. For Vela X-1, the analysis of a dataset recorded during a single dark moon interval reveals evidence for two short outbursts of pulsed TeV gamma ray emission. Chapter 8 reports the series of observations made of SMC X-1, 4U1626-67 and X0G21-72, and upper limits are placed on the TeV gamma ray emission from each. Finally, the results reported here are compared with the predictions of a number of theoretical models, some of which are found to give good agreement with the limits and detections derived in this work. A discussion of the status of this field and future observational prospects is also given

Aesthetic Perception, Attention and Aesthetic Psychology

What are the psychological foundations of aesthetic experience? Disagreements about how to answer this question underlie tensions between the experiences described by those in the developing field of everyday aesthetics and many art-centred accounts of aesthetic experience. I argue that neither has provided the psychological framework to support their arguments in favour of or against the extension of aesthetic experience into everyday life. Such a framework is required in order to reconcile the two fields. This thesis aims to develop an empirically informed aesthetic psychology which accommodates both everyday and paradigmatic aesthetic experience without compromising what is distinctive about each. In order to understand the oft-unacknowledged assumptions in everyday and mainstream accounts of aesthetic experience I distinguish between “broad” and “narrow” aesthetic psychology. I argue that each approach differs with respect to the necessity of attention for aesthetic experience. The narrow approach to aesthetic psychology underlies many contemporary accounts and places an “attention condition” on aesthetic experience; the broad approach underlies many accounts of everyday aesthetic experience and involves no such condition. I develop a broad psychological account of aesthetic perception as the perceptual representation of bound qualities and suggest that its minimal or “bare” form goes on in the absence of attention, whilst its “rich” form requires attention and supports characteristically appreciative activities of mind. Using contemporary empirical and philosophical work on attention and its relation to consciousness and cognition I argue that there is an attention condition on rich aesthetic perception (and aesthetic appreciation), but not on bare aesthetic perception: this establishes a broad aesthetic psychology. In this way I reconcile everyday and mainstream aesthetic experience by creating a continuum of aesthetic engagement which runs from the fleeting and unattended experiences of broad aesthetic psychology to the complex and appreciative experiences of narrow aesthetic psychology

A multi-stage drop-the-losers design for multi-arm clinical trials

Multi-arm multi-stage trials can improve the efficiency of the drug development process when multiple new treatments are available for testing. A group-sequential approach can be used in order to design multi-arm multi-stage trials, using an extension to Dunnett’s multiple-testing procedure. The actual sample size used in such a trial is a random variable that has high variability. This can cause problems when applying for funding as the cost will also be generally highly variable. This motivates a type of design that provides the efficiency advantages of a group-sequential multi-arm multi-stage design, but has a fixed sample size. One such design is the two-stage drop-the-losers design, in which a number of experimental treatments, and a control treatment, are assessed at a prescheduled interim analysis. The best-performing experimental treatment and the control treatment then continue to a second stage. In this paper, we discuss extending this design to have more than two stages, which is shown to considerably reduce the sample size required. We also compare the resulting sample size requirements to the sample size distribution of analogous group-sequential multi-arm multi-stage designs. The sample size required for a multi-stage drop-the-losers design is usually higher than, but close to, the median sample size of a group-sequential multi-arm multi-stage trial. In many practical scenarios, the disadvantage of a slight loss in average efficiency would be overcome by the huge advantage of a fixed sample size. We assess the impact of delay between recruitment and assessment as well as unknown variance on the drop-the-losers designs

Variations in the energy output and ATP pool during the growth of K. aerogenes in defined media

Thermal events accompanying the growth of K. aerogenes in batch culture in phosphate- and glucose-limited salts media were recorded using an LKB flow micro-calorimeter; changes in the cellular ATP content and growth parameters (biomass, CO2) were also measured. Calorimetric data is discussed in terms of the specific power output (P) and ATP data in terms of the ATP pool. Standard experimental and cultural conditions were established; at p = 0.95 the reproducibility of the heat output was 1%, and that of the ATP pool and other parameters was 3-4.5%. The specific power and ATP pool are similar indicators of metabolic activity; the P-t trace generally followed the course of the ATP profile. The values of P and the ATP pool increased rapidly at the start of the exponential growth phase; and on cessation of growth they decreased rapidly. During exponential growth under glucose-limitation the ATP profile oscillated about a mean value; the specific power remained nearly constant. The energy required for biosynthetic processes was calculated from mass and energy balances. Relative changes in this energy and the yield suggest that the biosynthetic energy is composed of the energy required for anabolism, for maintenance and for storage. Three different and distinct types of consecutive growth occurred under phosphate-limitation (glucose 60% in excess); mass and energy balances were established for each. The specific power output and cellular ATP profile decreased with decreasing availability of phosphate. It is apparent that cellular phosphate exists in two forms; free and fixed phosphate. The effect of increasing concentrations of sulphanilamide arid nalidixic acid (NA) on thermal and growth parameters was similar. NA exhibited a dual dose-related antibacterial potency; this is attributed to the change in its mode of action on RNA, DNA and protein synthesis. Changes in the P-t profiles were observed during the development of cellular resistance to NA.<p

Management of Wintering Short-eared Owls at Airports in the Lower Great Lakes Region

USDA Wildlife Services airport wildlife biologists have been tasked with reducing the hazards that raptors (including owls) pose to safe aircraft operations at airports and military airfields throughout the USA. A review of available wildlife strike information suggests short-eared owls (Asio flammeus) are frequently struck by aircraft during the winter months at numerous airports within the Lower Great Lakes Region of the United States. Further, this species is listed as ‘endangered’ by state fish and wildlife agencies in many states, although not at the federal level. Consequently, there is particular interest in developing non-lethal management tools for reducing the hazards posed by this species. In an effort to gain a better understanding of the efficacy of managing the hazards to aviation posed by short-eared owls, we developed methods to live-capture, mark with USGS aluminum leg bands, and translocate short-eared owls from airport environments (i.e., airfield areas) as part of the overall programs to reduce wildlife hazards to safe aircraft operations at airports. During 2012−2015, a total of 32 short-eared owls was live-captured, banded, and translocated to release sites approximately 64 to 80 km (40 to 50 miles) away from the airports. Only 1 short-eared owl (3%) was resighted and this bird was found on a different airport from where it had been translocated from. Future research in needed to evaluate the efficacy of translocating wintering short-eared owls from airport environments

Management of Wintering Short-eared Owls at Airports in the Lower Great Lakes Region

USDA Wildlife Services airport wildlife biologists have been tasked with reducing the hazards that raptors (including owls) pose to safe aircraft operations at airports and military airfields throughout the USA. A review of available wildlife strike information suggests short-eared owls (Asio flammeus) are frequently struck by aircraft during the winter months at numerous airports within the Lower Great Lakes Region of the United States. Further, this species is listed as ‘endangered’ by state fish and wildlife agencies in many states, although not at the federal level. Consequently, there is particular interest in developing non-lethal management tools for reducing the hazards posed by this species. In an effort to gain a better understanding of the efficacy of managing the hazards to aviation posed by short-eared owls, we developed methods to live-capture, mark with USGS aluminum leg bands, and translocate short-eared owls from airport environments (i.e., airfield areas) as part of the overall programs to reduce wildlife hazards to safe aircraft operations at airports. During 2012−2015, a total of 32 short-eared owls was live-captured, banded, and translocated to release sites approximately 64 to 80 km (40 to 50 miles) away from the airports. Only 1 short-eared owl (3%) was resighted and this bird was found on a different airport from where it had been translocated from. Future research in needed to evaluate the efficacy of translocating wintering short-eared owls from airport environments

Management of Wintering Short-eared Owls at Airports in the Lower Great Lakes Region

USDA Wildlife Services airport wildlife biologists have been tasked with reducing the hazards that raptors (including owls) pose to safe aircraft operations at airports and military airfields throughout the USA. A review of available wildlife strike information suggests short-eared owls (Asio flammeus) are frequently struck by aircraft during the winter months at numerous airports within the Lower Great Lakes Region of the United States. Further, this species is listed as ‘endangered’ by state fish and wildlife agencies in many states, although not at the federal level. Consequently, there is particular interest in developing non-lethal management tools for reducing the hazards posed by this species. In an effort to gain a better understanding of the efficacy of managing the hazards to aviation posed by short-eared owls, we developed methods to live-capture, mark with USGS aluminum leg bands, and translocate short-eared owls from airport environments (i.e., airfield areas) as part of the overall programs to reduce wildlife hazards to safe aircraft operations at airports. During 2012−2015, a total of 32 short-eared owls was live-captured, banded, and translocated to release sites approximately 64 to 80 km (40 to 50 miles) away from the airports. Only 1 short-eared owl (3%) was resighted and this bird was found on a different airport from where it had been translocated from. Future research in needed to evaluate the efficacy of translocating wintering short-eared owls from airport environments

Management of Wintering Short-eared Owls at Airports in the Lower Great Lakes Region

USDA Wildlife Services airport wildlife biologists have been tasked with reducing the hazards that raptors (including owls) pose to safe aircraft operations at airports and military airfields throughout the USA. A review of available wildlife strike information suggests short-eared owls (Asio flammeus) are frequently struck by aircraft during the winter months at numerous airports within the Lower Great Lakes Region of the United States. Further, this species is listed as ‘endangered’ by state fish and wildlife agencies in many states, although not at the federal level. Consequently, there is particular interest in developing non-lethal management tools for reducing the hazards posed by this species. In an effort to gain a better understanding of the efficacy of managing the hazards to aviation posed by short-eared owls, we developed methods to live-capture, mark with USGS aluminum leg bands, and translocate short-eared owls from airport environments (i.e., airfield areas) as part of the overall programs to reduce wildlife hazards to safe aircraft operations at airports. During 2012−2015, a total of 32 short-eared owls was live-captured, banded, and translocated to release sites approximately 64 to 80 km (40 to 50 miles) away from the airports. Only 1 short-eared owl (3%) was resighted and this bird was found on a different airport from where it had been translocated from. Future research in needed to evaluate the efficacy of translocating wintering short-eared owls from airport environments

Management of Wintering Short-eared Owls at Airports in the Lower Great Lakes Region

USDA Wildlife Services airport wildlife biologists have been tasked with reducing the hazards that raptors (including owls) pose to safe aircraft operations at airports and military airfields throughout the USA. A review of available wildlife strike information suggests short-eared owls (Asio flammeus) are frequently struck by aircraft during the winter months at numerous airports within the Lower Great Lakes Region of the United States. Further, this species is listed as ‘endangered’ by state fish and wildlife agencies in many states, although not at the federal level. Consequently, there is particular interest in developing non-lethal management tools for reducing the hazards posed by this species. In an effort to gain a better understanding of the efficacy of managing the hazards to aviation posed by short-eared owls, we developed methods to live-capture, mark with USGS aluminum leg bands, and translocate short-eared owls from airport environments (i.e., airfield areas) as part of the overall programs to reduce wildlife hazards to safe aircraft operations at airports. During 2012−2015, a total of 32 short-eared owls was live-captured, banded, and translocated to release sites approximately 64 to 80 km (40 to 50 miles) away from the airports. Only 1 short-eared owl (3%) was resighted and this bird was found on a different airport from where it had been translocated from. Future research in needed to evaluate the efficacy of translocating wintering short-eared owls from airport environments

Management of Wintering Short-eared Owls at Airports in the Lower Great Lakes Region

USDA Wildlife Services airport wildlife biologists have been tasked with reducing the hazards that raptors (including owls) pose to safe aircraft operations at airports and military airfields throughout the USA. A review of available wildlife strike information suggests short-eared owls (Asio flammeus) are frequently struck by aircraft during the winter months at numerous airports within the Lower Great Lakes Region of the United States. Further, this species is listed as ‘endangered’ by state fish and wildlife agencies in many states, although not at the federal level. Consequently, there is particular interest in developing non-lethal management tools for reducing the hazards posed by this species. In an effort to gain a better understanding of the efficacy of managing the hazards to aviation posed by short-eared owls, we developed methods to live-capture, mark with USGS aluminum leg bands, and translocate short-eared owls from airport environments (i.e., airfield areas) as part of the overall programs to reduce wildlife hazards to safe aircraft operations at airports. During 2012−2015, a total of 32 short-eared owls was live-captured, banded, and translocated to release sites approximately 64 to 80 km (40 to 50 miles) away from the airports. Only 1 short-eared owl (3%) was resighted and this bird was found on a different airport from where it had been translocated from. Future research in needed to evaluate the efficacy of translocating wintering short-eared owls from airport environments