532 research outputs found
A Search for Variable Stars and Planetary Occultations in NGC2301 I: Techniques
We observed the young open cluster NGC 2301 for 14 nights in Feb. 2004 using
the orthogonal transfer CCD camera (OPTIC). We used PSF shaping techniques
("square stars") during the observations allowing a larger dynamic range (4.5
magnitudes) of high photometric precision results (2 mmag) to be obtained.
These results are better than similar observing campaigns using standard CCD
imagers. This paper discusses our observational techniques and presents initial
results for the variability statistics found in NGC 2301. Details of the
variability statistics as functions of color, variability type, stellar type,
and cluster location will appear in paper II
The impact of cockpit automation on crew coordination and communication. Volume 1: Overview, LOFT evaluations, error severity, and questionnaire data
The purpose was to examine, jointly, cockpit automation and social processes. Automation was varied by the choice of two radically different versions of the DC-9 series aircraft, the traditional DC-9-30, and the glass cockpit derivative, the MD-88. Airline pilot volunteers flew a mission in the simulator for these aircraft. Results show that the performance differences between the crews of the two aircraft were generally small, but where there were differences, they favored the DC-9. There were no criteria on which the MD-88 crews performed better than the DC-9 crews. Furthermore, DC-9 crews rated their own workload as lower than did the MD-88 pilots. There were no significant differences between the two aircraft types with respect to the severity of errors committed during the Line-Oriented Flight Training (LOFT) flight. The attitude questionnaires provided some interesting insights, but failed to distinguish between DC-9 and MD-88 crews
A Corpus Investigation of Syntactic Embedding in Piraha
The Pirahã language has been at the center of recent debates in linguistics, in large part because it is claimed not to exhibit recursion, a purported universal of human language. Here, we present an analysis of a novel corpus of natural Pirahã speech that was originally collected by Dan Everett and Steve Sheldon. We make the corpus freely available for further research. In the corpus, Pirahã sentences have been shallowly parsed and given morpheme-aligned English translations. We use the corpus to investigate the formal complexity of Pirahã syntax by searching for evidence of syntactic embedding. In particular, we search for sentences which could be analyzed as containing center-embedding, sentential complements, adverbials, complementizers, embedded possessors, conjunction or disjunction. We do not find unambiguous evidence for recursive embedding of sentences or noun phrases in the corpus. We find that the corpus is plausibly consistent with an analysis of Pirahã as a regular language, although this is not the only plausible analysis
A Viral Ubiquitin Ligase Has Substrate Preferential SUMO Targeted Ubiquitin Ligase Activity that Counteracts Intrinsic Antiviral Defence
Intrinsic antiviral resistance represents the first line of intracellular defence against virus infection. During herpes simplex virus type-1 (HSV-1) infection this response can lead to the repression of viral gene expression but is counteracted by the viral ubiquitin ligase ICP0. Here we address the mechanisms by which ICP0 overcomes this antiviral response. We report that ICP0 induces the widespread proteasome-dependent degradation of SUMO-conjugated proteins during infection and has properties related to those of cellular SUMO-targeted ubiquitin ligases (STUbLs). Mutation of putative SUMO interaction motifs within ICP0 not only affects its ability to degrade SUMO conjugates, but also its capacity to stimulate HSV-1 lytic infection and reactivation from quiescence. We demonstrate that in the absence of this viral countermeasure the SUMO conjugation pathway plays an important role in mediating intrinsic antiviral resistance and the repression of HSV-1 infection. Using PML as a model substrate, we found that whilst ICP0 preferentially targets SUMO-modified isoforms of PML for degradation, it also induces the degradation of PML isoform I in a SUMO modification-independent manner. PML was degraded by ICP0 more rapidly than the bulk of SUMO-modified proteins in general, implying that the identity of a SUMO-modified protein, as well as the presence of SUMO modification, is involved in ICP0 targeting. We conclude that ICP0 has dual targeting mechanisms involving both SUMO- and substrate-dependent targeting specificities in order to counteract intrinsic antiviral resistance to HSV-1 infection
Kepler-432: a red giant interacting with one of its two long period giant planets
We report the discovery of Kepler-432b, a giant planet ()
transiting an evolved star with an orbital period of days. Radial velocities (RVs) reveal that
Kepler-432b orbits its parent star with an eccentricity of , which we also measure independently with
asterodensity profiling (AP; ), thereby confirming
the validity of AP on this particular evolved star. The well-determined
planetary properties and unusually large mass also make this planet an
important benchmark for theoretical models of super-Jupiter formation.
Long-term RV monitoring detected the presence of a non-transiting outer planet
(Kepler-432c; days), and adaptive optics imaging revealed a nearby
(0\farcs87), faint companion (Kepler-432B) that is a physically bound M dwarf.
The host star exhibits high signal-to-noise asteroseismic oscillations, which
enable precise measurements of the stellar mass, radius and age. Analysis of
the rotational splitting of the oscillation modes additionally reveals the
stellar spin axis to be nearly edge-on, which suggests that the stellar spin is
likely well-aligned with the orbit of the transiting planet. Despite its long
period, the obliquity of the 52.5-day orbit may have been shaped by star-planet
interaction in a manner similar to hot Jupiter systems, and we present
observational and theoretical evidence to support this scenario. Finally, as a
short-period outlier among giant planets orbiting giant stars, study of
Kepler-432b may help explain the distribution of massive planets orbiting giant
stars interior to 1 AU.Comment: 22 pages, 19 figures, 5 tables. Accepted to ApJ on Jan 24, 2015
(submitted Nov 11, 2014). Updated with minor changes to match published
versio
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Dynamic partnership: A new approach to EM technology commercialization and deployment
The task of restoring nuclear defense complex sites under the U.S. Department of Energy (DOE) Environmental Management (EM) Program presents an unprecedented challenge to the environmental restoration community. Effective and efficient cleanup requires the timely development or modification of novel cleanup technologies applicable to radioactive wastes. Fostering the commercialization of these innovative technologies is the mission of EM-50, the EM Program Office of Science and Technology. However, efforts are often arrested at the {open_quotes}valley of death,{close_quotes} the general term for barriers to demonstration, commercialization, and deployment. The Energy & Environmental Research Center (EERC), a not-for-profit, contract-supported organization focused on research, development, demonstration, and commercialization (RDD&C) of energy and environmental technologies, is in the second year of a cooperative agreement with the U.S. Department of Energy (DOE) Morgantown Energy Technology Center (METC) designed to deliver EM technologies into the commercial marketplace through a unique combination of technical support, real-world demonstration, and brokering. This paper profiles this novel approach, termed {open_quotes}Dynamic Partnership,{close_quotes} and reviews the application of this concept to the ongoing commercialization and deployment of four innovative cleanup technologies. 2 tabs
Controlling the rates of reductively-activated elimination from the (indol-3-yl)methyl position of indolequinones
A series of substituted 3-(4-nitrophenyloxy)methylindole-4,7-diones (Q) were synthesised. The effects of substitution patterns on the indole core on rates of elimination of 4-nitrophenol as a model for drug release following fragmentation of a phenolic ether linker were studied. After reduction to either the radical anion (Q ؒϪ ) or hydroquinone (QH 2 ) elimination of 4-nitrophenol occurred from the (indol-3-yl)methyl position. The half-lives , typical of tumour hypoxia, were t1 -2 ≈ 0.3-1.8 ms, the higher values associated with higher reduction potentials. Half-lives for the autoxidation of the QH 2 were markedly longer at the same oxygen concentration (t1 -2 ≈ 8-102 min) and longer still in the presence of 4 µmol dm Ϫ3 superoxide dismutase (t1 -2 ≈ 8-19 h). Although the indolequinones were able to eliminate 4-nitrophenol with high efficiency only Q ؒϪ radicals of the 3-carbinyl substituted derivatives did so with sufficiently short half-lives (t1 -2 ≈ 41-2 ms) to compete with electron transfer to oxygen and therefore have the potential to target the leaving group to hypoxic tissue. The hydroquinones are not sufficiently oxygen sensitive to prevent the elimination of 4-nitrophenol (t1 -2 ≈ 1.5-3.5 s) even at oxygen concentrations expected in normal tissue. By incorporating electron rich substituents at the indolyl carbinyl position it is possible to control the rate of reductive fragmentation. This may prove an important factor in the design of an indolequinone-based bioreductive drug delivery system
Strong coupling, discrete symmetry and flavour
We show how two principles - strong coupling and discrete symmetry - can work
together to generate the flavour structure of the Standard Model. We propose
that in the UV the full theory has a discrete flavour symmetry, typically only
associated with tribimaximal mixing in the neutrino sector. Hierarchies in the
particle masses and mixing matrices then emerge from multiple strongly coupled
sectors that break this symmetry. This allows for a realistic flavour
structure, even in models built around an underlying grand unified theory. We
use two different techniques to understand the strongly coupled physics:
confinement in N=1 supersymmetry and the AdS/CFT correspondence. Both
approaches yield equivalent results and can be represented in a clear,
graphical way where the flavour symmetry is realised geometrically.Comment: 31 pages, 5 figures, updated references and figure
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Mercury Information Clearinghouse
The Canadian Electricity Association (CEA) identified a need and contracted the Energy & Environmental Research Center (EERC) to create and maintain an information clearinghouse on global research and development activities related to mercury emissions from coal-fired electric utilities. With the support of CEA, the Center for Air Toxic Metals{reg_sign} (CATM{reg_sign}) Affiliates, and the U.S. Department of Energy (DOE), the EERC developed comprehensive quarterly information updates that provide a detailed assessment of developments in the various areas of mercury monitoring, control, policy, and research. A total of eight topical reports were completed and are summarized and updated in this final CEA quarterly report. The original quarterly reports can be viewed at the CEA Web site (www.ceamercuryprogram.ca). In addition to a comprehensive update of previous mercury-related topics, a review of results from the CEA Mercury Program is provided. Members of Canada's coal-fired electricity generation sector (ATCO Power, EPCOR, Manitoba Hydro, New Brunswick Power, Nova Scotia Power Inc., Ontario Power Generation, SaskPower, and TransAlta) and CEA, have compiled an extensive database of information from stack-, coal-, and ash-sampling activities. Data from this effort are also available at the CEA Web site and have provided critical information for establishing and reviewing a mercury standard for Canada that is protective of environment and public health and is cost-effective. Specific goals outlined for the CEA mercury program included the following: (1) Improve emission inventories and develop management options through an intensive 2-year coal-, ash-, and stack-sampling program; (2) Promote effective stack testing through the development of guidance material and the support of on-site training on the Ontario Hydro method for employees, government representatives, and contractors on an as-needed basis; (3) Strengthen laboratory analytical capabilities through analysis and quality assurance programs; and (4) Create and maintain an information clearinghouse to ensure that all parties can keep informed on global mercury research and development activities
Lensing in the Blue II: Estimating the Sensitivity of Stratospheric Balloons to Weak Gravitational Lensing
The Superpressure Balloon-borne Imaging Telescope (SuperBIT) is a
diffraction-limited, wide-field, 0.5 m, near-infrared to near-ultraviolet
observatory designed to exploit the stratosphere's space-like conditions.
SuperBIT's 2023 science flight will deliver deep, blue imaging of galaxy
clusters for gravitational lensing analysis. In preparation, we have developed
a weak lensing measurement pipeline with modern algorithms for PSF
characterization, shape measurement, and shear calibration. We validate our
pipeline and forecast SuperBIT survey properties with simulated galaxy cluster
observations in SuperBIT's near-UV and blue bandpasses. We predict imaging
depth, galaxy number (source) density, and redshift distribution for
observations in SuperBIT's three bluest filters; the effect of lensing sample
selections is also considered. We find that in three hours of on-sky
integration, SuperBIT can attain a depth of b = 26 mag and a total source
density exceeding 40 galaxies per square arcminute. Even with the application
of lensing-analysis catalog selections, we find b-band source densities between
25 and 30 galaxies per square arcminute with a median redshift of z = 1.1. Our
analysis confirms SuperBIT's capability for weak gravitational lensing
measurements in the blue.Comment: Submitted to Astronomical Journa
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