5,434 research outputs found
Comparison of Pollination Graphs
From the agent-based, correlated random walk model presented, we observe the effects of varying the maximum turning angle, δmax, tree density, ω, and pollen carryover, κmax, on the distribution of pollen within a tree population by examining pollination graphs. Varying maximum turning angle and pollen carryover alters the dispersal of pollen, which affects many measures of connectivity of the pollination graph. Among these measures the clustering coefficient of fathers is largest when δmax is between 60 and 90∘. The greatest effect of varying ω is not on the clustering coefficient of fathers, but on the other measures of genetic diversity. In particular when comparing simulations with randomly placed trees with that of actual tree placement of C. florida at the VCU Rice Center, it is clear that having specific tree locations is crucial in determining the properties of a pollination graph
Suppression of superconductivity in nanowires by bulk superconductors
Transport measurements were made on a system consisting of a zinc nanowire
array sandwiched between two bulk superconducting electrodes (Sn or In). It was
found that the superconductivity of Zn nanowires of 40 nm diameter is
suppressed either completely or partially by the superconducting electrodes.
When the electrodes are driven into their normal state by a magnetic field, the
nanowires switch back to their superconducting state. This phenomenon is
significantly weakened when one of the two superconducting electrodes is
replaced by a normal metal. The phenomenon is not seen in wires with diameters
equal to and thicker than 70 nm.Comment: 4 pages, 5 figure
Development Methods and a Scenegraph Animation API for Cluster Driven Immersive Applications
This paper presents a scenegraph animation application programming interface (API), known as the Animation Engine, which was constructed for software developers to easily perform smooth transitions and manipulations to scenegraph nodes. A developer can use one line of code to enter the property, end state and number of frames to describe the animation, then the Animation Engine handles the rest in the background. The goal of the Animation Engine is to provide a simple API that integrates into existing applications with minimal effort. Additionally, techniques to improve virtual reality (VR) application performance on a large computer cluster are presented. These techniques include maintaining high frame rates with 4096 × 4096 pixel textures, eliminating extraneous network traffic and reducing long model loading time. To demonstrate the Animation Engine and the development techniques, an application known as the Virtual Universe was created. The Virtual Universe, designed to run in a six walled CAVE, allows users to freely explore a set of space themed environments. The architecture and development techniques for writing a stable immersive VR application on a large computer cluster, in addition to the creation of the Animation Engine, is presented in this paper
Best practices to prevent transmission and control outbreaks of hand, foot, and mouth disease in childcare facilities: a systematic review.
INTRODUCTION: Hand, foot, and mouth disease continues to cause seasonal epidemics in the Asia-Pacific Region. Since the current Enterovirus 71 vaccines do not provide cross-protection for all Enterovirus species that cause hand, foot, and mouth disease, there is an urgent need to identify appropriate detection tools and best practice to prevent its transmission and to effectively control its outbreaks. This systematic review aimed to identify characteristics of outbreak and assess the impact and effectiveness of detection tools and public health preventive measures to interrupt transmission. The findings will be used to recommend policy on the most effective responses and interventions in Hong Kong to effectively minimise and contain the spread of the disease within childcare facilities. METHODS: We searched the following databases for primary studies written in Chinese or English: MEDLINE, EMBASE, Global Health, WHO Western Pacific Region Index Medicus database, China National Knowledge Infrastructure Databases, and Chinese Scientific Journals Database. Studies conducted during or retrospective to outbreaks of hand, foot, and mouth disease caused by Enterovirus 71 from 1980 to 2012 within childcare facilities and with a study population of 0 to 6 years old were included. RESULTS: Sixteen studies conducted on outbreaks in China showed that hand, foot, and mouth disease spread rapidly within the facility, with an outbreak length of 4 to 46 days, especially in those with delayed notification (after 24 hours) of clustered outbreak (with five or more cases discovered within the facility) to the local Center for Disease Control and Prevention and delayed implementation of a control response. The number of classes affected ranged from 1 to 13, and the attack rate for children ranged from 0.97% to 28.18%. CONCLUSIONS: Communication between key stakeholders about outbreak confirmation, risk assessment, and surveillance should be improved. Effective communication facilitates timely notification (within 24 hours) of clustered outbreaks to a local Center for Disease Control and Prevention. Timely implementation of a control response is effective in minimising incidence and length of an outbreak in childcare facilities. The government should provide incentives for childcare facilities to train infection control specialists who can serve as the first contact, knowledge, and communication points, as well as facilitate exchange of information and provision of support across stakeholders during a communicable disease epidemic
Lensed quasar search via time variability with the HSC transient survey
Gravitationally lensed quasars are useful for studying astrophysics and
cosmology, and enlarging the sample size of lensed quasars is important for
multiple studies. In this work, we develop a lens search algorithm for
four-image (quad) lensed quasars based on their time variability. In the
development of the lens search algorithm, we constructed a pipeline simulating
multi-epoch images of lensed quasars in cadenced surveys, accounting for quasar
variabilities, quasar hosts, lens galaxies, and the PSF variation. Applying the
simulation pipeline to the Hyper Suprime-Cam (HSC) transient survey, we
generated HSC-like difference images of the mock lensed quasars from Oguri &
Marshall's lens catalog. We further developed a lens search algorithm that
picks out variable objects as lensed quasar candidates based on their spatial
extent in the difference images. We tested our lens search algorithm with the
mock lensed quasars and variable objects from the HSC transient survey. Using
difference images from multiple epochs, our lens search algorithm achieves a
high true-positive rate (TPR) of 90.1% and a low false-positive rate (FPR) of
2.3% for the bright quads with wide separation. With a preselection of the
number of blobs in the difference image, we obtain a TPR of 97.6% and a FPR of
2.6% for the bright quads with wide separation. Even when difference images are
only available in one single epoch, our lens search algorithm can still detect
the bright quads with wide separation at high TPR of 97.6% and low FPR of 2.4%
in the optimal seeing scenario, and at TPR of and FPR of in
typical scenarios. Therefore, our lens search algorithm is promising and is
applicable to ongoing and upcoming cadenced surveys, particularly the HSC
transient survey and the Rubin Observatory Legacy Survey of Space and Time, for
finding new lensed quasar systems. [abridged]Comment: 15 pages, 11 figure
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