144 research outputs found
Discovery of a single faint AGN in a large sample of z > 5 Lyman break galaxies
No full textAs part of a large spectroscopic survey of z > 5 Lyman break galaxies (LBGs), we have identified a single source which is clearly hosting an active galactic nucleus (AGN). Out of a sample of more than 50 spectroscopically confirmed R-band dropout galaxies at z∼ 5 and above, only J104048.6−115550.2 at z= 5.44 shows evidence for a high ionization potential emission line indicating the presence of a hard ionizing continuum from an AGN. Like most objects in our sample the rest-frame-UV spectrum shows the UV continuum breaking across a Lyα line. Uniquely within this sample of LBGs, emission from N V is also detected, a clear signature of AGN photoionization. The object is spatially resolved in Hubble Space Telescope (HST) imaging. This, and the comparatively high Lyα/N V flux ratio indicates that the majority of the Lyα (and the UV continuum longward of it) originates from stellar photoionization, a product of the ongoing starburst in the LBG. Even without the AGN emission, this object would have been photometrically selected and spectroscopically confirmed as a Lyman break in our survey. The measured optical flux (IAB= 26.1) is therefore an upper limit to that from the AGN and is of order 100 times fainter than the majority of known quasars at these redshifts. The detection of a single object in our survey volume is consistent with the best current models of high redshift AGN luminosity function, providing a substantial fraction of such AGN is found within luminous starbursting galaxies. We discuss the cosmological implications of this discovery
Leaders’ experiences and perceptions implementing activity-based funding and pay-for-performance hospital funding models: A systematic review
No full textEffect of creatine supplementation on muscular strength and body composition following resistance training
No full textThis thesis was scanned from the print manuscript for digital preservation and is copyright the author.
Researchers can access this thesis by asking their local university, institution or public library to
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Cowpox virus infection in natural field vole Microtus agrestispopulations: significant negative impacts on survival
No full text1. Cowpox virus is an endemic virus circulating in populations of wild rodents. It has been implicated as a potential cause of population cycles in field voles Microtus agrestis L., in Britain, owing to a delayed density-dependent pattern in prevalence, but its impact on field vole demographic parameters is unknown. This study tests the hypothesis that wild field voles infected with cowpox virus have a lower probability of survival than uninfected individuals. 2. The effect of cowpox virus infection on the probability of an individual surviving to the next month was investigated using longitudinal data collected over 2 years from four grassland sites in Kielder Forest, UK. This effect was also investigated at the population level, by examining whether infection prevalence explained temporal variation in survival rates, once other factors influencing survival had been controlled for. 3. Individuals with a probability of infection, P(I), of 1 at a time when base survival rate was at median levels had a 22.4% lower estimated probability of survival than uninfected individuals, whereas those with a P(I) of 0.5 had a 10.4% lower survival. 4. At the population level, survival rates also decreased with increasing cowpox prevalence, with lower survival rates in months of higher cowpox prevalence. 5. Simple matrix projection models with 28 day time steps and two stages, with 71% of voles experiencing cowpox infection in their second month of life (the average observed seroprevalence at the end of the breeding season) predict a reduction in 28-day population growth rate during the breeding season from λ = 1.62 to 1.53 for populations with no cowpox infection compared with infected populations. 6. This negative correlation between cowpox virus infection and field vole survival, with its potentially significant effect on population growth rate, is the first for an endemic pathogen in a cyclic population of wild rodents
Fast and low loss flexoelectro-optic liquid crystal phase modulator with a chiral nematic reflector
No full text© 2019, The Author(s). In this paper, we demonstrate a flexoelectro-optic liquid crystal phase-only device that uses a chiral nematic reflector to achieve full 2π phase modulation. This configuration is found to be very tolerant to imperfections in the chiral nematic reflector provided that the flexoelectro-optic LC layer fulfils the half-wave condition. Encouragingly, the modulation in the phase, which operates at kHz frame rates, is also accompanied by low amplitude modulation. The configuration demonstrated herein is particularly promising for the development of next-generation liquid crystal on silicon spatial light modulators
An overview of corporate governance in China
No full textThe author examines corporate governance qualitatively and applies corporate governance principles to Chinese companies, especially the state owned enterprises. The paper reviews the meaning and importance of corporate governance, the institutional structures that exist, and the corporate governance problems that typically arise. A significant problem with achieving good corporate governance lies with the agency problem. Overcoming this problem therefore is crucial. Key characteristics of good corporate governance emerge. Good corporate governance depends upon company specific structures such as the board of directors as well as market information flows. Corporate governance is examined in its peculiarly Chinese setting. The paper traces the development of reform in China and how it has impacted corporate governance. Developments such as domestic listing and foreign listing are examined as to their impact on corporate governance. Chinese corporate governance still faces many challenges. Corporate governance is often weak because of a variety of problems. Among these are fragmented stock ownership, lack of a bond market, and poor quality information. Improving monitoring and the incentive structure remain significant challenges. Capital formation and securitization are often politically driven. State owned companies may have multiple masters, whose priorities may not lead to value creation. At the same time describing Chinese markets involves a moving target. Substantial changes have occurred in the last decade improving corporate governance and more changes will surely come soon
Health care leaders’ experiences implementing patient-based funding approaches: A systematic review
No full textDurability of direct immunofluorescence (DIF) slides stored at room temperature
No full textBackground: Prior studies suggested that direct immunofluorescence (DIF) slides can be stored at room temperature. Objectives: We sought to determine the durability of DIF slides stored at room temperature for 5 years. Methods: This was a retrospective study of 83 DIF slides archived at room temperature during 2010. The pattern of immunoreactants was compared with those noted in the original report. Results: Loss of reactivity was limited to cases with weak fluorescence at original diagnosis. Loss of IgG was noted in 12.5% of cases, IgA in 12%, C3 in 10%, and IgM in 9.75%. Fibrin showed no loss of reactivity. Preservation of immunofluorescence was not related to site of deposition. Overall, a reliable diagnosis could be made in 75 of 79 archived cases (94.9%). Limitations: Cases had been archived for periods varying from 4.5 to 5 years. Variations in processing and fluorochromes could affect durability. We have no way of knowing how long slides had been exposed to ultraviolet light at the time of initial examination. Conclusion: DIF showed excellent durability in slides kept at room temperature for 5 years.China Scholarship Council [201406015016]SCI(E)[email protected]
Preliminary results in the comparison of Skylab, ERTS and RB-57 images for the detection of lineaments and fractures in Precambrian, Paleozoic, and late Tertiary rocks on and near the Colorado Plateau, North-Central Arizona
No full textThere are no author-identified significant results in this report
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