1,550 research outputs found

    The Effects of Sex, Energy, and Environmental Conditions on the Movement Ecology of Migratory Bats

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    Lack of knowledge about the behaviour of migratory species during the migratory period is a major barrier to conservation efforts. In this thesis I focus primarily on differences between the sexes of the bat Lasionycteris noctivagans, during spring migration. Females are pregnant during spring migration and this overlap between migration and reproduction may affect the time and energy management of females as compared to males. In Chapter 2 I examine spring migration phenology of bats at a stopover site. Females arrived earlier than males, likely to give their pups a long growing season. Fat stores appeared to reflect a strategy to provision for upcoming lactation demands. In Chapter 3 I explore stopover behaviour and I show that despite the use of torpor to minimize roosting energy expenditure, cold weather extends stopover duration. There was no sex difference in the length of time spent at stopover. By regressing the time of night bats were captured against their fat and lean mass I demonstrate that bats have greater fat and lean masses closer to dawn, and therefore are likely using stopover periods to refuel. In Chapter 4 I compare sex and seasonal differences in daytime torpor use at stopover. I found that in spring bats used torpor for fewer hours than in autumn, even after accounting for the effect of ambient temperature. Further, females used torpor for fewer hours than males. I propose that these seasonal differences are due to lower prey abundance and predictability in spring; sex differences may be attributable to a higher foraging intensity by females compared to males. Finally, in Chapter 5 I use a radio-telemetry array in southwestern Ontario, Canada to track the spring and autumn long distance migratory movements of L. noctivagans, Lasiurus borealis, and Lasiurus cinereus. No migration corridors were identified in either season. Estimated migration speeds indicate that multiday stopovers are also used in the autumn. These studies combined show that sex affects the spring migration time and energy management of bats. Bat migration research is still in its formative stages and my studies provide new information on bat migration in North America

    The key aspects of innovation-oriented regional industrial and economic policy

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    Integration processes taking place in the economy, the new requirements to enhance the effectiveness of production during international competition as well as the need to ensure the social conditions lead to the development and implementation of innovation-oriented regional industrial and economic policy, which in its turn, requires adopting substantial organizational and economic recommendations

    A Population-Based Ultra-Widefield Digital Image Grading Study for Age-Related Macular Degeneration-Like Lesions at the Peripheral Retina.

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    Our understanding of the relevance of peripheral retinal abnormalities to disease in general and in age-related macular degeneration (AMD) in particular is limited by the lack of detailed peripheral imaging studies. The purpose of this study was to develop image grading protocols suited to ultra-widefield imaging (UWFI) in an aged population

    Changes in Body Condition of Hibernating Bats Support the Thrifty Female Hypothesis and Predict Consequences for Populations with White-Nose Syndrome

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    White-nose syndrome (WNS) is a new disease of bats that has devastated populations in eastern North America. Infection with the fungus, Geomyces destructans, is thought to increase the time bats spend out of torpor during hibernation, leading to starvation. Little is known about hibernation in healthy, free-ranging bats and more data are needed to help predict consequences of WNS. Trade-offs presumably exist between the energetic benefits and physiological/ecological costs of torpor, leading to the prediction that the relative importance of spring energy reserves should affect an individual's use of torpor and depletion of energy reserves during winter. Myotis lucifugus mate during fall and winter but females do not become pregnant until after spring emergence. Thus, female reproductive success depends on spring fat reserves while male reproductive success does not. Consequently, females should be “thrifty” in their use of fat compared to males. We measured body condition index (BCI; mass/forearm length) of 432 M. lucifugus in Manitoba, Canada during the winter of 2009/2010. Bats were captured during the fall mating period (n = 200), early hibernation (n = 125), and late hibernation (n = 128). Adult females entered hibernation with greater fat reserves and consumed those reserves more slowly than adult males and young of the year. Consequently, adult females may be more likely than males or young of the year to survive the disruption of energy balance associated with WNS, although surviving females may not have sufficient reserves to support reproduction

    Nonperturbative Approach to Circuit Quantum Electrodynamics

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    We outline a rigorous method which can be used to solve the many-body Schroedinger equation for a Coulomb interacting electronic system in an external classical magnetic field as well as a quantized electromagnetic field. Effects of the geometry of the electronic system as well as the polarization of the quantized electromagnetic field are explicitly taken into account. We accomplish this by performing repeated truncations of many-body spaces in order to keep the size of the many particle basis on a manageable level. The electron-electron and electron-photon interactions are treated in a nonperturbative manner using "exact numerical diagonalization". Our results demonstrate that including the diamagnetic term in the photon-electron interaction Hamiltonian drastically improves numerical convergence. Additionally, convergence with respect to the number of photon states in the joint photon-electron Fock space basis is fast. However, the convergence with respect to the number of electronic states is slow and is the main bottleneck in calculations.Comment: Revtex, pdflatex, 8 pages, with 5 included pdf figure

    Ectopic Cushing Syndrome Due to Colon Cancer With Dual Morphology

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    Efst ĂĄ sĂ­Ă°unni er hĂŠgt aĂ° nĂĄlgast greinina Ă­ heild sinni meĂ° ĂŸvĂ­ aĂ° smella ĂĄ hlekkinnWe report a case of colon cancer, and the most interesting presentation was Cushing’s syndrome (CS). A 72-year-old woman was diagnosed with CS when admitted to hospital because of NSTEMI and heart failure. The patient succumbed to her illness only 4 weeks after presentation. The colon cancer was a combined adenocarcinoma and small cell carcinoma, solely the latter component responsible for producing adrenocorticotropin hormone (ACTH)

    Design and development of a low temperature, inductance based high frequency ac susceptometer

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    We report on the development of an induction based low temperature high frequency ac susceptometer capable of measuring at frequencies up to 3.5 MHz and at temperatures between 2 K and 300 K. Careful balancing of the detection coils and calibration have allowed a sample magnetic moment resolution of 5×10−10Am25\times10^{-10} Am^2 at 1 MHz. We will discuss the design and characterization of the susceptometer, and explain the calibration process. We also include some example measurements on the spin ice material CdEr2_2S4_4 and iron oxide based nanoparticles to illustrate functionality

    Agreement between image grading of conventional (45°) and ultra wide-angle (200°) digital images in the macula in the Reykjavik eye study.

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    To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldPURPOSE: To establish the agreement between image grading of conventional (45°) and ultra wide-angle (200°) digital images in the macula. METHODS: In 2008, the 12-year follow-up was conducted on 573 participants of the Reykjavik Eye Study. This study included the use of the Optos P200C AF ultra wide-angle laser scanning ophthalmoscope alongside Zeiss FF 450 conventional digital fundus camera on 121 eyes with or without age-related macular degeneration using the International Classification System. Of these eyes, detailed grading was carried out on five cases each with hard drusen, geographic atrophy and chorioretinal neovascularisation, and six cases of soft drusen. Exact agreement and Îș-statistics were calculated. RESULTS: Comparison of the conventional and ultra wide-angle images in the macula showed an overall 96.43% agreement (Îș=0.93) with no disagreement at end-stage disease; although in one eye chorioretinal neovascularisation was graded as drusenoid pigment epithelial detachment. Of patients with drusen only, the exact agreement was 96.1%. The detailed grading showed no clinically significant disagreement between the conventional 45° and 200° images. CONCLUSIONS: On the basis of our results, there is a good agreement between grading conventional and ultra wide-angle images in the macul

    Percolation in invariant Poisson graphs with i.i.d. degrees

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    Let each point of a homogeneous Poisson process in R^d independently be equipped with a random number of stubs (half-edges) according to a given probability distribution mu on the positive integers. We consider translation-invariant schemes for perfectly matching the stubs to obtain a simple graph with degree distribution mu. Leaving aside degenerate cases, we prove that for any mu there exist schemes that give only finite components as well as schemes that give infinite components. For a particular matching scheme that is a natural extension of Gale-Shapley stable marriage, we give sufficient conditions on mu for the absence and presence of infinite components
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