3,151 research outputs found
The Lick AGN Monitoring Project 2011: Reverberation Mapping of Markarian 50
The Lick AGN Monitoring Project 2011 observing campaign was carried out over the course of 11 weeks in spring 2011. Here we present the first results from this program, a measurement of the broad-line reverberation lag in the Seyfert 1 galaxy Mrk 50. Combining our data with supplemental observations obtained prior to the start of the main observing campaign, our data set covers a total duration of 4.5 months. During this time, Mrk 50 was highly variable, exhibiting a maximum variability amplitude of a factor of ~4 in the U-band continuum and a factor of ~2 in the Hβ line. Using standard cross-correlation techniques, we find that Hβ and Hγ lag the V-band continuum by τ_(cen) = 10.64^(+0.82)_(–0.93) and 8.43^(+1.30)_(–1.28) days, respectively, while the lag of He II λ4686 is unresolved. The Hβ line exhibits a symmetric velocity-resolved reverberation signature with shorter lags in the high-velocity wings than in the line core, consistent with an origin in a broad-line region (BLR) dominated by orbital motion rather than infall or outflow. Assuming a virial normalization factor of f = 5.25, the virial estimate of the black hole mass is (3.2 ± 0.5) × 10^7 M_☉. These observations demonstrate that Mrk 50 is among the most promising nearby active galaxies for detailed investigations of BLR structure and dynamics
Comparison of hydrogen and methane as coolants in regeneratively cooled panels
Comparison of hydrogen and methane as coolants in regeneratively cooled panel
Nicotine Effects Surface Bound Enolase on Streptococcus mutans and Its Binding to Human Plasminogen
poster abstractStreptococcus mutans is the major bacterial agent responsible for dental caries. Previous research has shown that smokers have increased caries and that nicotine increases biofilm formation of S. mutans. S. mutans is also associated with atherosclerosis, another disease commonly found in smokers. However, little research has been done to investigate the direct effect of nicotine on the ability of S. mutans to bind to endothelial cells and lead to atherosclerosis. The two objectives of this study were to determine how nicotine affects the level of enolase, a glycolytic enzyme, on the surface of S. mutans, and next to determine its effect on binding of treated bacteria to human plasminogen, a protein present in the bloodstream. S. mutans strain UA159 was grown overnight in tryptic soy broth treated with 0, 0.5, 1, and 2 mg/mL nicotine at 37◦C in 5% CO2. These cells were used to coat a microtiter plate, and various levels of surface bound enolase and binding to plasminogen were determined using enzyme-linked immunosorbent assays (ELISA). A preliminary trial showed increase in both surface bound enolase and binding to plasminogen with increasing nicotine concentration. Similar results are to be expected with repetition of this procedure, indicating that nicotine up-regulates the bacterial expression of enolase and its binding to plasminogen, probably through plasminogen binding receptors, contributing to the virulence of S. mutans. Knowledge of the attachment mechanisms of S. mutans in the presence of tobacco may aid in prevention of tobacco-related atherosclerosis
The Effects of Transitional Yields on Adverse Selection in Crop Insurance
Transitional yields based on county average can be used by producers as the basis to obtain crop insurance on fields that have not previously produced the crop. Using field-level crop insurance contract data for several crops in five different growing regions we examine the impact of this asymmetric information on adverse selection. Our results indicate that adverse selection does exist from the use of transitional yields and that it is crop specific but not land-quality specific.adverse selection, crop insurance, transitional yields, Risk and Uncertainty, Q18,
Initial Public Offerings of Ballplayers
As a field study of choice under uncertainty, we examine baseball teams' investments in amateur players. Though most prospects fail to deliver any return on their multi-million dollar signing bonuses, returns on the minority who succeed easily offset these losses: the expected annual yield on the median first-round draftee is 33 percent. However, the pattern of returns is inconsistent with market efficiency. Yields are lower for high schoolers than collegians (27 percent vs. 43 percent), lower for pitchers than position players (24 percent vs. 41 percent), decline for later round long-shots, and may be negative under competitive bidding.Market efficiency; Bounded rationality; Prospect theory; Winner’s curse
Good governance in sport: a survey of UK national governing bodies of sport
This report presents the findings from a research project focusing on the governance
of national governing bodies of sport (NGBs) in the UK. Governance has become an
increasingly important issue that NGBs in the UK have had to address over the last
decade due to examples of poor management, financial failure, and increased public
funding for sport that have resulted in the need for more professional sports
administrative structures. These issues have been addressed during the last decade
by UK Sport and the Sports Councils as part of a Modernisation Programme aimed
at improving NGB governance.
The objective of this research project was to analyze standards of governance at UK
NGBs and consider the extent to which some of the recommendations from the
Modernisation Programme have been implemented. It is hoped that this will be the
first of an annual research project focusing on these issues and that future reports
will be able to track trends and changes in the way that NGBs are governed in the
UK. The research took place between October 2009 and January 2010 and has
been carried out by a team of three researchers from the Birkbeck Sport Business
Centre, a research centre in the Department of Management at Birkbeck, University
of London. The research team carried out an online survey in which all NGBs
recognised by each of the four home country sports councils – Sport England, Sport
Northern Ireland, sportscotland and the Sports Council for Wales – were invited to
take part. The findings of the report are based on responses provided by 60 NGBs.
The report presents detailed analysis of three key areas relating to NGB governance:
the board and committee; human resource management; and stakeholder
management and corporate responsibility
An overview of Space Communication Artificial Intelligence for Link Evaluation Terminal (SCAILET) Project
A software application to assist end-users of the link evaluation terminal (LET) for satellite communications is being developed. This software application incorporates artificial intelligence (AI) techniques and will be deployed as an interface to LET. The high burst rate (HBR) LET provides 30 GHz transmitting/20 GHz receiving (220/110 Mbps) capability for wideband communications technology experiments with the Advanced Communications Technology Satellite (ACTS). The HBR LET can monitor and evaluate the integrity of the HBR communications uplink and downlink to the ACTS satellite. The uplink HBR transmission is performed by bursting the bit-pattern as a modulated signal to the satellite. The HBR LET can determine the bit error rate (BER) under various atmospheric conditions by comparing the transmitted bit pattern with the received bit pattern. An algorithm for power augmentation will be applied to enhance the system's BER performance at reduced signal strength caused by adverse conditions
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