10,793 research outputs found
Air Force Eastern Test Range Central Telemetry Station (TEL-IV)
We have had a vast increase in the amount and rate of data telemetered back to the Eastern Test Range from both missiles and manned and unmanned space vehicles over the past few years.
In 1961, as a major part of the Eastern Test Range Telemetry Modernization Program, development of a new Central Telemetry Station at Kennedy Space Center was initiated. It was designated Telemetry Station IV (TEL-IV), The objectives of the new Central Telemetry Station (TEL-IV) have been established as:
1. Provide simultaneous multiple mission capability for both pre-launch and launch support. 2. Serve as a central telemetry station for receiving , processing, and distributing the telemetered data from remote mobile and landbased stations. 3. Provide minimum turn around time between mission setups and permit rapid equipment changes in the event of failures. 4. Provide real time and non - real time capability to meet all program requirements.
In order to achieve these objectives, the integrated systems design departed from the traditional ground station concept of hard wire or manual patching. Instead, the station was designed .and based on a central control technique. The system setup and equipment assignment for a given mission\u27s support is accomplished automatically by a launch coordinator through a special purpose , wired-program digital data processor and a cross-bar switching network
A Survey of UV Bright Sources Behind the Halo of M31
We have performed a wide-area ultraviolet (UV) imaging survey using the
GALaxy Evolution eXplorer (GALEX) to search for bright, point-like UV sources
behind M31's extended halo. Our survey consisted of 46 pointings covering an
effective area of ~50 deg^2, in both the far-UV and near-UV channels. We
combined these data with optical R-band observations acquired with the WIYN
Mosaic-1 imager on the Kitt Peak National Observatory 0.9m WIYN telescope. An
analysis of the brightness and colors of sources matched between our
photometric catalogs yielded ~100 UV-bright quasar candidates. We have obtained
discovery spectra for 76 of these targets with the Kast spectrometer on the
Lick 3m telescope and confirm 30 active galactic nuclei and quasars, 29
galaxies at z > 0.02 including several early-type systems, 16 Galactic stars
(hot main-sequence stars), and one featureless source previously identified as
a BL Lac object. Future UV spectroscopy of the brightest targets with the
Cosmic Origins Spectrograph on the Hubble Space Telescope will enable a
systematic search for diffuse gas in the extended halo of M31.Comment: 10 pages, 10 figures. Accepted to MNRA
Blue-Light-Emitting Color Centers in High-Quality Hexagonal Boron Nitride
Light emitters in wide band gap semiconductors are of great fundamental
interest and have potential as optically addressable qubits. Here we describe
the discovery of a new color center in high-quality hexagonal boron nitride
(h-BN) with a sharp emission line at 435 nm. The emitters are activated and
deactivated by electron beam irradiation and have spectral and temporal
characteristics consistent with atomic color centers weakly coupled to lattice
vibrations. The emitters are conspicuously absent from commercially available
h-BN and are only present in ultra-high-quality h-BN grown using a
high-pressure, high-temperature Ba-B-N flux/solvent, suggesting that these
emitters originate from impurities or related defects specific to this unique
synthetic route. Our results imply that the light emission is activated and
deactivated by electron beam manipulation of the charge state of an
impurity-defect complex
Analysis and interpretation of a fast limb CME with eruptive prominence, C-flare and EUV dimming
Coronal Mass ejections or CMEs are large dynamical solar-corona events. The
mass balance and kinematics of a fast limb CME, including its prominence
progenitor and the associated flare, will be compared with computed magnetic
structures to look for their origin and effect.
Multi-wavelength ground-based and space-borne observations are used to study
a fast W-limb CME event of December 2, 2003, taking into account both on and
off disk observations. Its erupting prominence is measured at high cadence with
the Pic du Midi full H-alpha line-flux imaging coronagraph. EUV images from
space instruments are processed including difference imaging. SOHO/LASCO images
are used to study the mass excess and motions. A fast bright expanding coronal
loop is identified in the region recorded slightly later by GOES as a C7.2
flare, followed by a brightening and an acceleration phase of the erupting
material with both cool and hot components. The total coronal radiative flux
dropped by 5 percent in the EUV channels, revealing a large dimming effect at
and above the limb. The typical 3-part structure observed 1 hour later shows a
core shaped similarly to the eruptive filament/prominence. The total measured
mass of the escaping CME (1.5x10to16 g from C2 LASCO observations) definitely
exceeds the estimated mass of the escaping cool prominence material although
assumptions made to analyse the Ha erupting prominence, as well as the
corresponding EUV darkening of the filament observed several days before, made
this evaluation uncertain by a factor of 2. From the current free extrapolation
we discuss the shape of the magnetic neutral surface and a possible scenario
leading to an instability, including the small scale dynamics inside and around
the filament.Comment: 11 pages, 9 figure
Fragment screening reveals salicylic hydroxamic acid as an inhibitor of <em>Trypanosoma brucei</em> GPI GlcNAc-PI de-N-acetylase
The zinc-metalloenzyme GlcNAc-PI de-N-acetylase is essential for the biosynthesis of mature GPI anchors and has been genetically validated in the bloodstream form of Trypanosoma brucei, which causes African sleeping sickness. We screened a focused library of zinc-binding fragments and identified salicylic hydroxamic acid as a GlcNAc-PI de-N-acetylase inhibitor with high ligand efficiency. This is the first small molecule inhibitor reported for the trypanosome GPI pathway. Investigating the structure activity relationship revealed that hydroxamic acid and 2-OH are essential for potency, and that substitution is tolerated at the 4- and 5-positions
WaveletQuant, an improved quantification software based on wavelet signal threshold de-noising for labeled quantitative proteomic analysis
<p>Abstract</p> <p>Background</p> <p>Quantitative proteomics technologies have been developed to comprehensively identify and quantify proteins in two or more complex samples. Quantitative proteomics based on differential stable isotope labeling is one of the proteomics quantification technologies. Mass spectrometric data generated for peptide quantification are often noisy, and peak detection and definition require various smoothing filters to remove noise in order to achieve accurate peptide quantification. Many traditional smoothing filters, such as the moving average filter, Savitzky-Golay filter and Gaussian filter, have been used to reduce noise in MS peaks. However, limitations of these filtering approaches often result in inaccurate peptide quantification. Here we present the WaveletQuant program, based on wavelet theory, for better or alternative MS-based proteomic quantification.</p> <p>Results</p> <p>We developed a novel discrete wavelet transform (DWT) and a 'Spatial Adaptive Algorithm' to remove noise and to identify true peaks. We programmed and compiled WaveletQuant using Visual C++ 2005 Express Edition. We then incorporated the WaveletQuant program in the <b>Trans-Proteomic Pipeline (TPP)</b>, a commonly used open source proteomics analysis pipeline.</p> <p>Conclusions</p> <p>We showed that WaveletQuant was able to quantify more proteins and to quantify them more accurately than the ASAPRatio, a program that performs quantification in the TPP pipeline, first using known mixed ratios of yeast extracts and then using a data set from ovarian cancer cell lysates. The program and its documentation can be downloaded from our website at <url>http://systemsbiozju.org/data/WaveletQuant</url>.</p
Controllability and controller-observer design for a class of linear time-varying systems
“The final publication is available at Springer via http://dx.doi.org/10.1007/s10852-012-9212-6"In this paper a class of linear time-varying control systems is considered. The time variation consists of a scalar time-varying coefficient multiplying the state matrix of an otherwise time-invariant system. Under very weak assumptions of this coefficient, we show that the controllability can be assessed by an algebraic rank condition, Kalman canonical decomposition is possible, and we give a method for designing a linear state-feedback controller and Luenberger observer
Large-scale Bright Fronts in the Solar Corona: A Review of "EIT waves"
``EIT waves" are large-scale coronal bright fronts (CBFs) that were first
observed in 195 \AA\ images obtained using the Extreme-ultraviolet Imaging
Telescope (EIT) onboard the \emph{Solar and Heliospheric Observatory (SOHO)}.
Commonly called ``EIT waves", CBFs typically appear as diffuse fronts that
propagate pseudo-radially across the solar disk at velocities of 100--700 km
s with front widths of 50-100 Mm. As their speed is greater than the
quiet coronal sound speed (200 km s) and comparable to the
local Alfv\'{e}n speed (1000 km s), they were initially
interpreted as fast-mode magnetoacoustic waves ().
Their propagation is now known to be modified by regions where the magnetosonic
sound speed varies, such as active regions and coronal holes, but there is also
evidence for stationary CBFs at coronal hole boundaries. The latter has led to
the suggestion that they may be a manifestation of a processes such as Joule
heating or magnetic reconnection, rather than a wave-related phenomena. While
the general morphological and kinematic properties of CBFs and their
association with coronal mass ejections have now been well described, there are
many questions regarding their excitation and propagation. In particular, the
theoretical interpretation of these enigmatic events as magnetohydrodynamic
waves or due to changes in magnetic topology remains the topic of much debate.Comment: 34 pages, 19 figure
Partially-erupting prominences: a comparison between observations and model-predicted observables
<p><b>Aims:</b> We investigate several partially-erupting prominences to study their relationship with other CME-associated phenomena and compare these observations with observables predicted by a model of partially-expelled-flux-ropes (Gibson & Fan 2006a, ApJ, 637, L65; 2006b, J. Geophys. Res., 111, 12103).</p>
<p><b>Methods:</b> We studied 6 selected events with partially-erupting prominences using multi-wavelength observations recorded by the Extreme-ultraviolet Imaging Telescope (EIT), Transition Region and Coronal Explorer (TRACE), Mauna Loa Solar Observatory (MLSO), Big Bear Solar Observatory (BBSO), and Soft X-ray Telescope (SXT). The observational features associated with partially-erupting prominences were then compared with the predicted observables from the model.</p>
<p><b>Results:</b> The partially-expelled-flux-rope (PEFR) model can explain the partial eruption of these prominences, and in addition predicts a variety of other CME-related observables that provide evidence of internal reconnection during eruption. We find that all of the partially-erupting prominences studied in this paper exhibit indirect evidence of internal reconnection. Moreover, all cases showed evidence of at least one observable unique to the PEFR model, e.g., dimmings external to the source region and/or a soft X-ray cusp overlying a reformed sigmoid.</p>
<p><b>Conclusions:</b> The PEFR model provides a plausible mechanism to explain the observed evolution of partially-erupting-prominence-associated CMEs in our study.</p>
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