541 research outputs found
Real-Time Chromakey Matting Using Image Statistics
Given a video signal, we generate an alpha matte based on the chromakey information. The computation is done in interactive-time using pixel shaders. To accomplish this, we use Principle Components Analysis to generate a linear transformation matrix where the resulting color triplets Euclidean distance is directly related to the probability that the color exists in the chromakey spectrum. The result of this process is a trimap of the video signals opacity. To solve the alpha matte from the trimap, we minimize an energy function constrained by the trimap with gradient descent. This energy function is based on the least-squared error of overlapping neighborhoods around each pixel and is independent of the background or foreground color
Guidelines for OLAC Video Game Genre Terms (olacvggt)
A thesaurus of video game genre terms with a corresponding MARC authority record
Revisiting with Chandra the Scaling Relations of the X-ray Emission Components (Binaries, Nuclei and Hot Gas) of Early Type Galaxies
We have selected a sample of 30 normal (non-cD) early type galaxies, for all
of which optical spectroscopy is available, and which have been observed with
Chandra to a depth such to insure the detection of bright low-mass X-ray
binaries (LMXBs) with Lx>1e38 erg/s. This sample includes a larger fraction of
gas-poor galaxies than previously studied samples, and covers a wide range of
stellar luminosity, velocity dispersion, GC specific frequency, and stellar
age. We derive X-ray luminosities (or upper limits) from the different
significant X-ray components of these galaxies: nuclei, detected and undetected
LMXBs, coronally active binaries (ABs), cataclysmic variables (CVs), and hot
gas. The ABs and CVs contribution is estimated from the Lx-LK scaling relation
of M31 and M32. The contribution of undetected LMXBs is estimated both by
fitting the spectra of the unresolved X-ray emission and by extrapolating the
LMXB X-ray luminosity function. The results for the nuclei are consistent with
those discussed by Pellegrini (2010). We derive a revised scaling relation
between the integrated X-ray luminosity of LMXBs in a galaxy and the LK
luminosity of the host galaxy: Lx(LMXB)/LK ~ 1e29 erg s-1 LK-1 with 50% 1sigma
rms; moreover, we also obtain a tighter LX(LMXB)/LK - SN relation than
previously published. We revisit the relations between hot gas content and
other galaxy parameters. finding a steeper LX(gas)-LK relation with larger
scatter than reported in the literature. We find a positive correlation between
the luminosity and temperature of the hot ISM, significantly tighter than
reported by earlier studies.[abridged
Defining a link with asthma in mice congenitally deficient in eosinophils
Eosinophils are often dominant inflammatory cells present in the lungs of asthma patients. Nonetheless, the role of these leukocytes remains poorly understood. We have created a transgenic line of mice (PHIL) that are specifically devoid of eosinophils, but otherwise have a full complement of hematopoietically derived cells. Allergen challenge of PHIL mice demonstrated that eosinophils were required for pulmonary mucus accumulation and the airway hyperresponsiveness associated with asthma. The development of an eosinophi-less mouse now permits an unambiguous assessment of a number of human diseases that have been linked to this granulocyte, including allergic diseases, parasite infections, and tumorigenesis
Hybrid Wing Body Aircraft Acoustic Test Preparations and Facility Upgrades
NASA is investigating the potential of acoustic shielding as a means to reduce the noise footprint at airport communities. A subsonic transport aircraft and Langley's 14- by 22-foot Subsonic Wind Tunnel were chosen to test the proposed "low noise" technology. The present experiment studies the basic components of propulsion-airframe shielding in a representative flow regime. To this end, a 5.8-percent scale hybrid wing body model was built with dual state-of-the-art engine noise simulators. The results will provide benchmark shielding data and key hybrid wing body aircraft noise data. The test matrix for the experiment contains both aerodynamic and acoustic test configurations, broadband turbomachinery and hot jet engine noise simulators, and various airframe configurations which include landing gear, cruise and drooped wing leading edges, trailing edge elevons and vertical tail options. To aid in this study, two major facility upgrades have occurred. First, a propane delivery system has been installed to provide the acoustic characteristics with realistic temperature conditions for a hot gas engine; and second, a traversing microphone array and side towers have been added to gain full spectral and directivity noise characteristics
First delivery of a COVID-19 positive patient in Cameroon
Since its appearance in China in December 2019, COVID-19 which is caused by the SARS-CoV-2 virus has become a real global health problem. Pregnant women are not immune to this novel infection, which makes it difficult for proper management of pregnancy and childbirth. Authors present here the first case of childbirth in Cameroon of a 19-year-old adolescent tested positive for COVID-19
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