3,022 research outputs found
Comparison of Trained and Untrained Novice Driversâ Gaze Behavior in Risky and Non-Risky Scenarios
PC-based training programs have been developed that have been shown to improve novice driversâ hazard anticipation skills. Such programs give novice drivers information about particular driving situations (scenarios) where hidden threats could appear. We wanted to know whether this improvement in trained novice driversâ scanning skills was simply because the trained drivers were scanning more in general or, instead, were scanning more specifically in the scenarios in which potential threats could appear. In order to evaluate this question, we trained 11 novice drivers using a PC-based program and then compared their hazard anticipation performance on a driving simulator with the hazard anticipation performance of 11 untrained novice drivers. The driversâ eye movements were recorded for the duration of the drives. The glances of the drivers to the right (the correct response in most of the risky scenarios) were analyzed for each of the relevant risky scenarios and for stretches of non-risky situations. The trained drivers did look to the right 6.5% more in the non-risky situations than did the untrained drivers, although the difference was far from significant. However, the trained drivers looked to the right 32.7% more in the risky scenarios than in the non-risky situations, indicating they were discriminating quite well between the two situations. The untrained drivers also showed a smaller, but significant, discrimination between the risky scenarios and non-risky situations, as they looked to the right 18.9% more in the risky scenarios than in the non-risky stretches
The complete genome of klassevirus â a novel picornavirus in pediatric stool
<p>Abstract</p> <p>Background</p> <p>Diarrhea kills 2 million children worldwide each year, yet an etiological agent is not found in approximately 30â50% of cases. Picornaviral genera such as enterovirus, kobuvirus, cosavirus, parechovirus, hepatovirus, teschovirus, and cardiovirus have all been found in human and animal diarrhea. Modern technologies, especially deep sequencing, allow rapid, high-throughput screening of clinical samples such as stool for new infectious agents associated with human disease.</p> <p>Results</p> <p>A pool of 141 pediatric gastroenteritis samples that were previously found to be negative for known diarrheal viruses was subjected to pyrosequencing. From a total of 937,935 sequence reads, a collection of 849 reads distantly related to Aichi virus were assembled and found to comprise 75% of a novel picornavirus genome. The complete genome was subsequently cloned and found to share 52.3% nucleotide pairwise identity and 38.9% amino acid identity to Aichi virus. The low level of sequence identity suggests a novel picornavirus genus which we have designated klassevirus. Blinded screening of 751 stool specimens from both symptomatic and asymptomatic individuals revealed a second positive case of klassevirus infection, which was subsequently found to be from the index case's 11-month old twin.</p> <p>Conclusion</p> <p>We report the discovery of human klassevirus 1, a member of a novel picornavirus genus, in stool from two infants from Northern California. Further characterization and epidemiological studies will be required to establish whether klasseviruses are significant causes of human infection.</p
Predispositions and the Political Behavior of American Economic Elites: Evidence from Technology Entrepreneurs
Economic elites regularly seek to exert political influence. But what policies do they support? Many accounts implicitly assume economic elites are homogeneous and that increases in their political power will increase inequality. We shed new light on heterogeneity in economic elites' political preferences, arguing that economic elites from an industry can share distinctive preferences due in part to sharing distinctive predispositions. Consequently, how increases in economic elites' influence affect inequality depends on which industry's elites are gaining influence and which policy issues are at stake. We demonstrate our argument with four original surveys, including the two largest political surveys of American economic elites to date: one of technology entrepreneursâwhose influence is burgeoningâand another of campaign donors. We show that technology entrepreneurs support liberal redistributive, social, and globalistic policies but conservative regulatory policiesâa bundle of preferences rare among other economic elites. These differences appear to arise partly from their distinctive predispositions
Electroconvective flow in presence of polyethylene glycol oligomer additives
Metal electrodeposition in batteries is fundamentally unstable and affected
by different instabilities depending on operating conditions and chemical
composition. Particularly at high charging rates, a hydrodynamic instability
called electroconvection sets in that aggravates the situation by creating
non-uniform ion flux and preferential deposition at the electrode. Here, we
experimentally investigate how oligomer additives interact with the
hydrodynamic instability at a cation selective interface. From electrochemical
measurements and direct visualization experiments, we find that
electroconvection is delayed and suppressed at all voltage in the presence of
oligomers. Our results also reveal that it is important to consider the role of
polymers at the interface, in addition to their bulk effects, to understand the
stabilization effect and its mechanism
First Measurement of the Clustering Evolution of Photometrically-Classified Quasars
We present new measurements of the quasar autocorrelation from a sample of
\~80,000 photometrically-classified quasars taken from SDSS DR1. We find a
best-fit model of for the angular
autocorrelation, consistent with estimates from spectroscopic quasar surveys.
We show that only models with little or no evolution in the clustering of
quasars in comoving coordinates since z~1.4 can recover a scale-length
consistent with local galaxies and Active Galactic Nuclei (AGNs). A model with
little evolution of quasar clustering in comoving coordinates is best explained
in the current cosmological paradigm by rapid evolution in quasar bias. We show
that quasar biasing must have changed from b_Q~3 at a (photometric) redshift of
z=2.2 to b_Q~1.2-1.3 by z=0.75. Such a rapid increase with redshift in biasing
implies that quasars at z~2 cannot be the progenitors of modern L* objects,
rather they must now reside in dense environments, such as clusters. Similarly,
the duration of the UVX quasar phase must be short enough to explain why local
UVX quasars reside in essentially unbiased structures. Our estimates of b_Q are
in good agreement with recent spectroscopic results, which demonstrate the
implied evolution in b_Q is consistent with quasars inhabiting halos of similar
mass at every redshift. Treating quasar clustering as a function of both
redshift and luminosity, we find no evidence for luminosity dependence in
quasar clustering, and that redshift evolution thus affects quasar clustering
more than changes in quasars' luminosity. We provide a new method for
quantifying stellar contamination in photometrically-classified quasar catalogs
via the correlation function.Comment: 34 pages, 10 figures, 1 table, Accepted to ApJ after: (i) Minor
textual changes; (ii) extra points added to Fig.
Bostonia: The Boston University Alumni Magazine. Volume 12
Founded in 1900, Bostonia magazine is Boston Universityâs main alumni publication
Submaximal Oxygen Uptake Kinetics, Functional Mobility, and Physical Activity in Older Adults with Heart Failure and Reduced Ejection Fraction
Background: Submaximal oxygen uptake measures are more feasible and may better predict clinical cardiac outcomes than maximal tests in older adults with heart failure (HF). We examined relationships between maximal oxygen uptake, submaximal oxygen kinetics, functional mobility, and physical activity in older adults with HF and reduced ejection fraction.
Methods: Older adults with HF and reduced ejection fraction (n = 25, age 75 ± 7 years) were compared to 25 healthy age- and gender-matched controls. Assessments included a maximal treadmill test for peak oxygen uptake (VO2peak), oxygen uptake kinetics at onset of and on recovery from a submaximal treadmill test, functional mobility testing [Get Up and Go (GUG), Comfortable Gait Speed (CGS), Unipedal Stance (US)], and self-reported physical activity (PA).
Results: Compared to controls, HF had worse performance on GUG, CGS, and US, greater delays in submaximal oxygen uptake kinetics, and lower PA. In controls, VO2peak was more strongly associated with functional mobility and PA than submaximal oxygen uptake kinetics. In HF patients, submaximal oxygen uptake kinetics were similarly associated with GUG and CGS as VO2peak, but weakly associated with PA.
Conclusions: Based on their mobility performance, older HF patients with reduced ejection fraction are at risk for adverse functional outcomes. In this population, submaximal oxygen uptake measures may be equivalent to VO2 peak in predicting functional mobility, and in addition to being more feasible, may provide better insight into how aerobic function relates to mobility in older adults with HF
Five High-Redshift Quasars Discovered in Commissioning Imaging Data of the Sloan Digital Sky Survey
We report the discovery of five quasars with redshifts of 4.67 - 5.27 and
z'-band magnitudes of 19.5-20.7 M_B ~ -27. All were originally selected as
distant quasar candidates in optical/near-infrared photometry from the Sloan
Digital Sky Survey (SDSS), and most were confirmed as probable high-redshift
quasars by supplementing the SDSS data with J and K measurements. The quasars
possess strong, broad Lyman-alpha emission lines, with the characteristic sharp
cutoff on the blue side produced by Lyman-alpha forest absorption. Three
quasars contain strong, broad absorption features, and one of them exhibits
very strong N V emission. The amount of absorption produced by the Lyman-alpha
forest increases toward higher redshift, and that in the z=5.27 object (D_A ~
0.7) is consistent with a smooth extrapolation of the absorption seen in lower
redshift quasars. The high luminosity of these objects relative to most other
known objects at z >~ 5 makes them potentially valuable as probes of early
quasar properties and of the intervening intergalactic medium.Comment: 13 pages in LaTex format, two postscirpt figures. Submitted to the
Astronomical Journa
- âŠ