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Search Results: 1 - 10 of 326294 matches for " S. Gray "
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The World Wide Telescope: An Archetype for Online Science
Jim Gray,Alexander S. Szalay
Computer Science , 2004,
Abstract: Most scientific data will never be directly examined by scientists; rather it will be put into online databases where it will be analyzed and summarized by computer programs. Scientists increasingly see their instruments through online scientific archives and analysis tools, rather than examining the raw data. Today this analysis is primarily driven by scientists asking queries, but scientific archives are becoming active databases that self-organize and recognize interesting and anomalous facts as data arrives. In some fields, data from many different archives can be cross-correlated to produce new insights. Astronomy presents an excellent example of these trends; and, federating Astronomy archives presents interesting challenges for computer scientists.
Where the Rubber Meets the Sky: Bridging the Gap between Databases and Science
Jim Gray,Alexander S. Szalay
Computer Science , 2005,
Abstract: Scientists in all domains face a data avalanche - both from better instruments and from improved simulations. We believe that computer science tools and computer scientists are in a position to help all the sciences by building tools and developing techniques to manage, analyze, and visualize peta-scale scientific information. This article is summarizes our experiences over the last seven years trying to bridge the gap between database technology and the needs of the astronomy community in building the World-Wide Telescope.
All Complete Intersection Calabi-Yau Four-Folds
James Gray,Alexander S. Haupt,Andre Lukas
Mathematics , 2013, DOI: 10.1007/JHEP07(2013)070
Abstract: We present an exhaustive, constructive, classification of the Calabi-Yau four-folds which can be described as complete intersections in products of projective spaces. A comprehensive list of 921,497 configuration matrices which represent all topologically distinct types of complete intersection Calabi-Yau four-folds is provided and can be downloaded at http://www-thphys.physics.ox.ac.uk/projects/CalabiYau/Cicy4folds/index.html . The manifolds have non-negative Euler characteristics in the range 0 - 2610. This data set will be of use in a wide range of physical and mathematical applications. Nearly all of these four-folds are elliptically fibered and are thus of interest for F-theory model building.
Topological Invariants and Fibration Structure of Complete Intersection Calabi-Yau Four-Folds
James Gray,Alexander S. Haupt,Andre Lukas
Mathematics , 2014, DOI: 10.1007/JHEP09(2014)093
Abstract: We investigate the mathematical properties of the class of Calabi-Yau four-folds recently found in [arXiv:1303.1832]. This class consists of 921,497 configuration matrices which correspond to manifolds that are described as complete intersections in products of projective spaces. For each manifold in the list, we compute the full Hodge diamond as well as additional topological invariants such as Chern classes and intersection numbers. Using this data, we conclude that there are at least 36,779 topologically distinct manifolds in our list. We also study the fibration structure of these manifolds and find that 99.95 percent can be described as elliptic fibrations. In total, we find 50,114,908 elliptic fibrations, demonstrating the multitude of ways in which many manifolds are fibered. A sub-class of 26,088,498 fibrations satisfy necessary conditions for admitting sections. The complete data set can be downloaded at http://www-thphys.physics.ox.ac.uk/projects/CalabiYau/Cicy4folds/index.html .
Petabyte Scale Data Mining: Dream or Reality?
Alexander S. Szalay,Jim Gray,Jan vandenBerg
Computer Science , 2002, DOI: 10.1117/12.461427
Abstract: Science is becoming very data intensive1. Today's astronomy datasets with tens of millions of galaxies already present substantial challenges for data mining. In less than 10 years the catalogs are expected to grow to billions of objects, and image archives will reach Petabytes. Imagine having a 100GB database in 1996, when disk scanning speeds were 30MB/s, and database tools were immature. Such a task today is trivial, almost manageable with a laptop. We think that the issue of a PB database will be very similar in six years. In this paper we scale our current experiments in data archiving and analysis on the Sloan Digital Sky Survey2,3 data six years into the future. We analyze these projections and look at the requirements of performing data mining on such data sets. We conclude that the task scales rather well: we could do the job today, although it would be expensive. There do not seem to be any show-stoppers that would prevent us from storing and using a Petabyte dataset six years from today.
An Assembler Driven Verification Methodology (ADVM)
John S. Macbeth,Dietmar Heinz,Ken Gray
Computer Science , 2007,
Abstract: This paper presents an overview of an assembler driven verification methodology (ADVM) that was created and implemented for a chip card project at Infineon Technologies AG. The primary advantage of this methodology is that it enables rapid porting of directed tests to new targets and derivatives, with only a minimum amount of code refactoring. As a consequence, considerable verification development time and effort was saved.
Cultured Alveolar Epithelial Cells From Septic Rats Mimic In Vivo Septic Lung
Taylor S. Cohen,Gladys Gray Lawrence,Susan S. Margulies
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0011322
Abstract: Sepsis results in the formation of pulmonary edema by increasing in epithelial permeability. Therefore we hypothesized that alveolar epithelial cells isolated from septic animals develop tight junctions with different protein composition and reduced barrier function relative to alveolar epithelial cells from healthy animals. Male rats (200–300g) were sacrificed 24 hours after cecal ligation and double puncture (2CLP) or sham surgery. Alveolar epithelial cells were isolated and plated on fibronectin-coated flexible membranes or permeable, non-flexible transwell substrates. After a 5 day culture period, cells were either lysed for western analysis of tight junction protein expressin (claudin 3, 4, 5, 7, 8, and 18, occludin, ZO-1, and JAM-A) and MAPk (JNK, ERK, an p38) signaling activation, or barrier function was examined by measuring transepithelial resistance (TER) or the flux of two molecular tracers (5 and 20 ?). Inhibitors of JNK (SP600125, 20 μM) and ERK (U0126, 10 μM) were used to determine the role of these pathways in sepsis induced epithelial barrier dysfunction. Expression of claudin 4, claudin 18, and occludin was significantly lower, and activation of JNK and ERK signaling pathways was significantly increased in 2CLP monolayers, relative to sham monolayers. Transepithelial resistance of the 2CLP monolayers was reduced significantly compared to sham (769 and 1234 ohm-cm2, respectively), however no significant difference in the flux of either tracer was observed. Inhibition of ERK, not JNK, significantly increased TER and expression of claudin 4 in 2CLP monolayers, and prevented significant differences in claudin 18 expression between 2CLP and sham monolayers. We conclude that alveolar epithelial cells isolated from septic animals form confluent monolayers with impaired barrier function compared to healthy monolayers, and inhibition of ERK signaling partially reverses differences between these monolayers. This model provides a unique preparation for probing the mechanisms by which sepsis alters alveolar epithelium.
Cycles, the Degree Distance, and the Wiener Index  [PDF]
Daniel Gray, Hua Wang
Open Journal of Discrete Mathematics (OJDM) , 2012, DOI: 10.4236/ojdm.2012.24031
Abstract: The degree distance of a graph G is , where and are the degrees of vertices , and is the distance between them. The Wiener index is defined as . An elegant result (Gutman; Klein, Mihali?,, Plav?i? and Trinajsti?) is known regarding their correlation, that for a tree T with n vertices. In this note, we extend this study for more general graphs that have frequent appearances in the study of these indices. In particular, we develop a formula regarding their correlation, with an error term that is presented with explicit formula as well as sharp bounds for unicyclic graphs and cacti with given parameters.
OnabotulinumtoxinA Nerve Blocks in the Treatment of Occipital Neuralgia  [PDF]
Andrew Ea, Terence Gray
Pain Studies and Treatment (PST) , 2016, DOI: 10.4236/pst.2016.43005
Abstract: Occipital neuralgia is characterized by severe pain, accompanied by tenderness and trigger points, in the distribution of the greater, lesser, and/or third occipital nerves. Occipital neuralgia is typically idiopathic, but also is characterized as a common form of posttraumatic headache. Typical treatments include nerve blocks with local anesthetic, nerve stimulation, pulsed radiofrequency, and cryoablation. OnabotulinumtoxinA (ONA) has recently been utilized in nerve blocks to treat occipital neuralgia, with the potential for a longer duration of pain relief than local anesthetic. Our study retrospectively examined 63 patients treated for occipital neuralgia, including 19 with ONA. 80 - 155 units of ONA were administered bilaterally in the surrounding musculature. A total of 61 patients, including 17 of those subsequently treated with ONA, were treated with local anesthetic, using a 1:1 mixture of 0.25% bupivacaine and 1% lidocaine, plus triamcinolone. Patients reported VAS pain scores before and after their procedures, and again during 4-week follow-up visits. Information on opioid use, overall pain relief, and duration of full relief was also recorded upon follow-up. Patients treated with ONA exhibited significant decreases in average VAS pain scores from 4.1 ± 2.6 pre-procedure to 2.1 ± 2.4 post-procedure (p = 2 × 10 -5), and 3.0 ± 2.5 4 weeks later (p = 0.0234). Mean overall relief was 75.8% ± 25.0%. Treatment with local anesthetic suggested equally efficacious reduction of VAS scores; however, treatment with ONA showed a significantly higher percentage of overall pain relief leading to follow-up. Opioid use did not exhibit significant change, regardless of treatment type. Our results support the hypothesis that use of Onabotulinum-toxinA in occipital nerve blocks leads to significant decreases in pain, while possibly exhibiting a longer duration of action than that of local anesthetic.
OnabotulinumtoxinA in the Treatment of Occipital Neuralgia Following Gunshot Injury  [PDF]
Andrew Ea, Terence Gray
Pain Studies and Treatment (PST) , 2016, DOI: 10.4236/pst.2016.44007
Abstract: Occipital neuralgia, while typically idiopathic in presentation, is a common form of posttraumatic headache. It is associated with severe pain in the greater, lesser, and/or third occipital nerves, and often accompanied by tenderness or trigger points in the surrounding musculature. OnabotulinumtoxinA (ONA) has been recently utilized in nerve blocks to treat occipital neuralgia, but current literature supporting such use is scarce. We describe a case of occipital neuralgia in a patient following C1 fracture and vertebral artery dissection due to gunshot injury. Successful treatment with bilateral ONA nerve blocks led to an 80% - 90% improvement in pain, with decreased Visual Analog Scale (VAS) pain scores immediately following treatment and upon follow-up 1 month later.
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