2,821 research outputs found
A Journal for the Astronomical Computing Community?
One of the Birds of a Feather (BoF) discussion sessions at ADASS XX
considered whether a new journal is needed to serve the astronomical computing
community. In this paper we discuss the nature and requirements of that
community, outline the analysis that led us to propose this as a topic for a
BoF, and review the discussion from the BoF session itself. We also present the
results from a survey designed to assess the suitability of astronomical
computing papers of different kinds for publication in a range of existing
astronomical and scientific computing journals. The discussion in the BoF
session was somewhat inconclusive, and it seems likely that this topic will be
debated again at a future ADASS or in a similar forum.Comment: 4 pages, no figures; to appear in proceedings of ADASS X
Deep ocean disposal of sewage sludge off Orange County, California: a research plan
Even though the discharge of sludge into the ocean via an outfall is not now permitted, this research plan has been prepared to show what could be learned with a full scale experimental sludge discharge of 150 dry tons/day by the County Sanitation Districts of Orange County into deep water (over 1000 feet). To provide a wide range of inputs and evaluation, a broad-based Research Planning Committee was established to advise the Environmental Quality Laboratory on the overall content and details of the research plan. Two meetings were held at EQL on: March 4-5, 1982: The entire Committee July 19-20, 1982: A working subgroup of the Committee The entire Committee is listed in Appendix B, with footnotes to indicate meeting attendance. Those unable to come to a meeting were asked to comment on the drafts by mail or telephone. We gratefully acknowledge the members of the Research Planning Committee for their generous help in formulating the research tasks and reviewing report drafts
Astronomy and Computing: a New Journal for the Astronomical Computing Community
We introduce \emph{Astronomy and Computing}, a new journal for the growing
population of people working in the domain where astronomy overlaps with
computer science and information technology. The journal aims to provide a new
communication channel within that community, which is not well served by
current journals, and to help secure recognition of its true importance within
modern astronomy. In this inaugural editorial, we describe the rationale for
creating the journal, outline its scope and ambitions, and seek input from the
community in defining in detail how the journal should work towards its
high-level goals.Comment: 5 pages, no figures; editorial for first edition of journa
Status and Future Perspectives for Lattice Gauge Theory Calculations to the Exascale and Beyond
In this and a set of companion whitepapers, the USQCD Collaboration lays out
a program of science and computing for lattice gauge theory. These whitepapers
describe how calculation using lattice QCD (and other gauge theories) can aid
the interpretation of ongoing and upcoming experiments in particle and nuclear
physics, as well as inspire new ones.Comment: 44 pages. 1 of USQCD whitepapers
Classifying short genomic fragments from novel lineages using composition and homology
<p>Abstract</p> <p>Background</p> <p>The assignment of taxonomic attributions to DNA fragments recovered directly from the environment is a vital step in metagenomic data analysis. Assignments can be made using <it>rank-specific </it>classifiers, which assign reads to taxonomic labels from a predetermined level such as named species or strain, or <it>rank-flexible </it>classifiers, which choose an appropriate taxonomic rank for each sequence in a data set. The choice of rank typically depends on the optimal model for a given sequence and on the breadth of taxonomic groups seen in a set of close-to-optimal models. Homology-based (<it>e.g</it>., LCA) and composition-based (<it>e.g</it>., PhyloPythia, TACOA) rank-flexible classifiers have been proposed, but there is at present no hybrid approach that utilizes both homology and composition.</p> <p>Results</p> <p>We first develop a hybrid, rank-specific classifier based on BLAST and Naïve Bayes (NB) that has comparable accuracy and a faster running time than the current best approach, PhymmBL. By substituting LCA for BLAST or allowing the inclusion of suboptimal NB models, we obtain a rank-flexible classifier. This hybrid classifier outperforms established rank-flexible approaches on simulated metagenomic fragments of length 200 bp to 1000 bp and is able to assign taxonomic attributions to a subset of sequences with few misclassifications. We then demonstrate the performance of different classifiers on an enhanced biological phosphorous removal metagenome, illustrating the advantages of rank-flexible classifiers when representative genomes are absent from the set of reference genomes. Application to a glacier ice metagenome demonstrates that similar taxonomic profiles are obtained across a set of classifiers which are increasingly conservative in their classification.</p> <p>Conclusions</p> <p>Our NB-based classification scheme is faster than the current best composition-based algorithm, Phymm, while providing equally accurate predictions. The rank-flexible variant of NB, which we term ε-NB, is complementary to LCA and can be combined with it to yield conservative prediction sets of very high confidence. The simple parameterization of LCA and ε-NB allows for tuning of the balance between more predictions and increased precision, allowing the user to account for the sensitivity of downstream analyses to misclassified or unclassified sequences.</p
Functional/thermal verification and validation of an S-band radio for the nanosatellites
© 2018 COSPAR An S-band radio designed with commercial-grade components for the nanosatellites is functionally and thermally characterized for quiet transmission. The QPSK modulation impairments are minor over −20 °C to +50 °C at 24, 26, 28 and 30 dBm RF levels. The channel response is linear in error vector magnitude, frequency, phase, amplitude and IQ errors. On the average, the stability of amplifier bias and nonlinearity gives −22 dBc maximum upper/lower adjacent channel power and 1.27 MHz occupied channel bandwidth. The acceptable level test results provide good confidence toward robust space-to-earth transmission in variable solar weather at low earth orbital altitudes
How to Block Cartel Formation and Price-Fixing
Abstract written by the AEI-Brookings Joint Center: Allowing foreign buyers of goods produced by international cartels to pursue civil antitrust damages in U.S. courts would better deter cartel formation and price-fixing than do sanctions currently imposed by global criminal and civil justice systems.Technology and Industry, Regulatory Reform, Other Topics
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Multivariate and Univariate Neuroimaging Biomarkers of Alzheimer's Disease
We performed univariate and multivariate discriminant analysis of FDG-PET scans to evaluate their ability to identify Alzheimer's disease (AD). FDG-PET scans came from two sources: 17 AD patients and 33 healthy elderly controls were scanned at the University of Michigan; 102 early AD patients and 20 healthy elderly controls were scanned at the Technical University of Munich, Germany. We selected a derivation sample of 20 AD patients and 20 healthy controls matched on age with the remainder divided into 5 replication samples. The sensitivity and specificity of diagnostic AD-markers and threshold criteria from the derivation sample were determined in the replication samples. Although both univariate and multivariate analyses produced markers with high classification accuracy in the derivation sample, the multivariate marker's diagnostic performance in the replication samples was superior. Further, supplementary analysis showed its performance to be unaffected by the loss of key regions. Multivariate measures of AD utilize the covariance structure of imaging data and provide complementary, clinically relevant information that may be superior to univariate measures
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