1,841 research outputs found
Spitzer Planet Limits around the Pulsating White Dwarf GD66
We present infrared observations in search of a planet around the white
dwarf, GD66. Time-series photometry of GD66 shows a variation in the arrival
time of stellar pulsations consistent with the presence of a planet with mass >
2.4Mj. Any such planet is too close to the star to be resolved, but the
planet's light can be directly detected as an excess flux at 4.5um. We observed
GD66 with the two shorter wavelength channels of IRAC on Spitzer but did not
find strong evidence of a companion, placing an upper limit of 5--7Mj on the
mass of the companion, assuming an age of 1.2--1.7Gyr.Comment: 10 pages, accepted by Ap
Creating a Discipline-specific Commons for Infectious Disease Epidemiology
Objective: To create a commons for infectious disease (ID) epidemiology in
which epidemiologists, public health officers, data producers, and software
developers can not only share data and software, but receive assistance in
improving their interoperability. Materials and Methods: We represented 586
datasets, 54 software, and 24 data formats in OWL 2 and then used logical
queries to infer potentially interoperable combinations of software and
datasets, as well as statistics about the FAIRness of the collection. We
represented the objects in DATS 2.2 and a software metadata schema of our own
design. We used these representations as the basis for the Content, Search,
FAIR-o-meter, and Workflow pages that constitute the MIDAS Digital Commons.
Results: Interoperability was limited by lack of standardization of input and
output formats of software. When formats existed, they were human-readable
specifications (22/24; 92%); only 3 formats (13%) had machine-readable
specifications. Nevertheless, logical search of a triple store based on named
data formats was able to identify scores of potentially interoperable
combinations of software and datasets. Discussion: We improved the findability
and availability of a sample of software and datasets and developed metrics for
assessing interoperability. The barriers to interoperability included poor
documentation of software input/output formats and little attention to
standardization of most types of data in this field. Conclusion: Centralizing
and formalizing the representation of digital objects within a commons promotes
FAIRness, enables its measurement over time and the identification of
potentially interoperable combinations of data and software.Comment: 12 pages, 6 figure
Back reaction of a long range force on a Friedmann-Robertson-Walker background
It is possible that there may exist long-range forces in addition to gravity.
In this paper we construct a simple model for such a force based on exchange of
a massless scalar field and analyze its effect on the evolution of a
homogeneous Friedmann-Robertson-Walker cosmology. The presence of such an
interaction leads to an equation of state characterized by positive pressure
and to resonant particle production similar to that observed in preheating
scenarios.Comment: 14 pages, 6 color Postscript figures, LaTe
Aircraft accident report: NASA 712, Convair 990, N712NA, March Air Force Base, California, July 17, 1985, facts and analysis
On July 17, l985, at 1810 P.d.t., NASA 712, a Convair 990 aircraft, was destroyed by fire at March Air Force Base, California. The fire started during the rollout after the pilot rejected the takeoff on runway 32. The rejected takeoff was initiated during the takeoff roll because of blown tires on the right landing gear. During the rollout, fragments of either the blown tires or the wheel/brake assemblies penetrated a right-wing fuel tank forward of the right main landing gear. Leaking fuel ignited while the aircraft was rolling, and fire engulfed the right wing and the fuselage after the aircraft was stopped on the runway. The 4-man flightcrew and the 15 scientists and technicians seated in the cabin evacuated the aircraft without serious injury. The fire was not extinguished by crash/rescue efforts and the aircraft was destroyed
Fungal Adenylyl Cyclase Acts As a Signal Sensor and Integrator and Plays a Central Role in Interaction with Bacteria
10.1371/journal.ppat.1003612PLoS Pathogens910
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Open Science principles for accelerating trait-based science across the Tree of Life.
Synthesizing trait observations and knowledge across the Tree of Life remains a grand challenge for biodiversity science. Species traits are widely used in ecological and evolutionary science, and new data and methods have proliferated rapidly. Yet accessing and integrating disparate data sources remains a considerable challenge, slowing progress toward a global synthesis to integrate trait data across organisms. Trait science needs a vision for achieving global integration across all organisms. Here, we outline how the adoption of key Open Science principles-open data, open source and open methods-is transforming trait science, increasing transparency, democratizing access and accelerating global synthesis. To enhance widespread adoption of these principles, we introduce the Open Traits Network (OTN), a global, decentralized community welcoming all researchers and institutions pursuing the collaborative goal of standardizing and integrating trait data across organisms. We demonstrate how adherence to Open Science principles is key to the OTN community and outline five activities that can accelerate the synthesis of trait data across the Tree of Life, thereby facilitating rapid advances to address scientific inquiries and environmental issues. Lessons learned along the path to a global synthesis of trait data will provide a framework for addressing similarly complex data science and informatics challenges
The Sloan Digital Sky Survey-II Supernova Survey: Search Algorithm and Follow-up Observations
The Sloan Digital Sky Survey-II Supernova Survey has identified a large
number of new transient sources in a 300 sq. deg. region along the celestial
equator during its first two seasons of a three-season campaign. Multi-band
(ugriz) light curves were measured for most of the sources, which include solar
system objects, Galactic variable stars, active galactic nuclei, supernovae
(SNe), and other astronomical transients. The imaging survey is augmented by an
extensive spectroscopic follow-up program to identify SNe, measure their
redshifts, and study the physical conditions of the explosions and their
environment through spectroscopic diagnostics. During the survey, light curves
are rapidly evaluated to provide an initial photometric type of the SNe, and a
selected sample of sources are targeted for spectroscopic observations. In the
first two seasons, 476 sources were selected for spectroscopic observations, of
which 403 were identified as SNe. For the Type Ia SNe, the main driver for the
Survey, our photometric typing and targeting efficiency is 90%. Only 6% of the
photometric SN Ia candidates were spectroscopically classified as non-SN Ia
instead, and the remaining 4% resulted in low signal-to-noise, unclassified
spectra. This paper describes the search algorithm and the software, and the
real-time processing of the SDSS imaging data. We also present the details of
the supernova candidate selection procedures and strategies for follow-up
spectroscopic and imaging observations of the discovered sources.Comment: Accepted for publication in The Astronomical Journal (66 pages, 13
figures); typos correcte
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