1,961 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
Performing texts; playing with jazz aesthetics
Despite all the critical attention jazz has received in recent years from scholars in other fields---literature, history, political science, cultural studies---very little headway has been made in understanding what jazz aesthetics are and how they might inform other forms of cultural and artistic expression. Part of the difficulty lies in the time-bound, performative nature of the artform and the fact that it is primarily a non-discursive means of expression; that is to say, jazz does not translate well.
This dissertation attempts to evoke and inhabit jazz aesthetics rather than trying to define, categorize or delineate them. Alternating between close reading, formal musical analysis, musicology and narrative improvisation, this performance sounds much in the manner of a jazz set in which the musicians work through a series of styles, forms and settings. The texts and approaches taken here are a mixture of the familiar and the unexpected. Thelonious Monk is discussed as a formalist of the highest order; Langston Hughes is not read as a jazz poet ; James Baldwin is argued to be more concerned with jazz brothers than literary fathers; Frank Zappa becomes one of the keepers of the jazz flame. Between these ostensibly conventional chapters lives a counter-melody, an autobiography at times parodic, satirical, self-reflexive and allusive that mimics, mocks, pays tribute to, improvises and signifies upon other less scholarly forms of jazz writing .
Although any number of elements suggestive of a jazz aesthetic are located in various texts---defamiliarization, reciprocity, incremental repetition, collective contextualization---no attempt is made to codify or delimit an understanding of jazz aesthetics. Rather, the performance is meant to organically give rise to and embody the aesthetic process itself. Jazz is all about telling your version of the story in close aural proximity to others who are simultaneously telling theirs. Each individual narrative is both tempered and enlarged in a process of collective contextualization. I think that is about as (dangerously) close as one would want to come to capturing jazz aesthetics in a declarative sentence
Toward a framework for data quality in cloud-based health information system
This Cloud computing is a promising platform for health information systems in order to reduce costs and improve accessibility. Cloud computing represents a shift away from computing being purchased as a product to be a service delivered over the Internet to customers. Cloud computing paradigm is becoming one of the popular IT infrastructures for facilitating Electronic Health Record (EHR) integration and sharing. EHR is defined as a repository of patient data in digital form. This record is stored and exchanged securely and accessible by different levels of authorized users. Its key purpose is to support the continuity of care, and allow the exchange and integration of medical information for a patient. However, this would not be achieved without ensuring the quality of data populated in the healthcare clouds as the data quality can have a great impact on the overall effectiveness of any system. The assurance of the quality of data used in healthcare systems is a pressing need to help the continuity and quality of care. Identification of data quality dimensions in healthcare clouds is a challenging issue as data quality of cloud-based health information systems arise some issues such as the appropriateness of use, and provenance. Some research proposed frameworks of the data quality dimensions without taking into consideration the nature of cloud-based healthcare systems. In this paper, we proposed an initial framework that fits the data quality attributes. This framework reflects the main elements of the cloud-based healthcare systems and the functionality of EHR
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
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The importance of including habitat-specific behaviour in models of butterfly movement
Dispersal is a key process affecting population persistence and major factors affecting dispersal rates are the amounts, connectedness and properties of habitats in landscapes. We present new data on the butterfly Maniola jurtina in flower-rich and flower-poor habitats that demonstrates how movement and behaviour differ between sexes and habitat types, and how this effects consequent dispersal rates. Females had higher flight speeds than males but their total time in flight was four times less. The effect of habitat type was strong for both sexes, flight speeds were ~2.5x and ~1.7x faster on resource-poor habitats for males and females respectively, and flights were approximately 50% longer. With few exceptions females oviposited in the mown grass habitat, likely because growing grass offers better food for emerging caterpillars, but they foraged in the resource-rich habitat. It seems that females faced a trade-off between ovipositing without foraging in the mown grass or foraging without ovipositing where flowers were abundant. We show that taking account of habitat-dependent differences in activity, here categorised as flight or non-flight, is crucial to obtaining good fits of an individual-based model to observed movement. An important implication of this finding is that incorporating habitat-specific activity budgets is likely necessary for predicting longer-term dispersal in heterogeneous habitats as habitat-specific behaviour substantially influences the mean (>30% difference) and kurtosis (1.4x difference) of dispersal kernels. The presented IBMs provide a simple method to explicitly incorporate known activity and movement rates when predicting dispersal in changing and heterogeneous landscapes
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