3,100 research outputs found
Correspondence: Letter from William E. Flaherty to Ms. Elaine Gordon, Chairperson on Subcommittee II of the Florida House of Representatives’ Committee on Regulatory Reform
The Transformation of American Law, 1780-1860
A Review of The Transformation of American Law, 1780-1860 by Morton J. Horwit
Wave propagation and earth satellite radio emission studies
Radio propagation studies of the ionosphere using satellite radio beacons are described. The ionosphere is known as a dispersive, inhomogeneous, irregular and sometimes even nonlinear medium. After traversing through the ionosphere the radio signal bears signatures of these characteristics. A study of these signatures will be helpful in two areas: (1) It will assist in learning the behavior of the medium, in this case the ionosphere. (2) It will provide information of the kind of signal characteristics and statistics to be expected for communication and navigational satellite systems that use the similar geometry
Application of Fast Pressure Sensitive Paint in Hypervelocity Flow
The development of fast responding pressure sensitive paints for measurements in high-enthalpy, hypersonic flows is reported. Data are obtained for at plate boundary layers in
an impulse facility with typical test gas times on the order of hundreds of microseconds.
The fast pressure sensitive paint is found to have the required response time and sufficient
signal level to visualize vortical boundary layer structures in a Mach 5.12 freestream. The
flow behind protuberance strips with different geometries is evaluated with measurements
of the vortex frequency and diameter, as well as breakdown distance. Comparisons with
static pressure measurements made using pressure taps show differences of up to a factor
of three, and calibration sources as well as an alternative lifetime measurement method
remain to be investigated
High power operation of an X-band gyrotwistron
We report the first experimental verification of a gyrotwistron amplifier. The device utilized a single 9.858 GHz, TE011 cavity, a heavily attenuated drift tube, and a long tapered output waveguide section. With a 440 kV, 200-245 A, 1 μs electron beam and a sharply tapered axial magnetic field, peak powers above 21 MW were achieved with a gain near 24 dB. Performance was limited by competition from a fundamental TE11 mode. A multimode code was developed to analyze this system, and simulations were in good agreement with the experiment
Considerations for a design and operations knowledge support system for Space Station Freedom
Engineering and operations of modern engineered systems depend critically upon detailed design and operations knowledge that is accurate and authoritative. A design and operations knowledge support system (DOKSS) is a modern computer-based information system providing knowledge about the creation, evolution, and growth of an engineered system. The purpose of a DOKSS is to provide convenient and effective access to this multifaceted information. The complexity of Space Station Freedom's (SSF's) systems, elements, interfaces, and organizations makes convenient access to design knowledge especially important, when compared to simpler systems. The life cycle length, being 30 or more years, adds a new dimension to space operations, maintenance, and evolution. Provided here is a review and discussion of design knowledge support systems to be delivered and operated as a critical part of the engineered system. A concept of a DOKSS for Space Station Freedom (SSF) is presented. This is followed by a detailed discussion of a DOKSS for the Lyndon B. Johnson Space Center and Work Package-2 portions of SSF
Evidence for Dynamical Changes in a Transitional Protoplanetary Disk with Mid-infrared Variability
We present multi-epoch Spitzer Space Telescope observations of the
transitional disk LRLL 31 in the 2-3 Myr-old star forming region IC 348. Our
measurements show remarkable mid-infrared variability on timescales as short as
one week. The infrared continuum emission exhibits systematic
wavelength-dependent changes that suggest corresponding dynamical changes in
the inner disk structure and variable shadowing of outer disk material. We
propose several possible sources for the structural changes, including a
variable accretion rate or a stellar or planetary companion embedded in the
disk. Our results indicate that variability studies in the infrared can provide
important new constraints on protoplanetary disk behavior.Comment: 15 pages, 4 figures, accepted to ApJ Letter
Expression of Drug Targets in Patients Treated with Sorafenib, Carboplatin and Paclitaxel
Introduction: Sorafenib, a multitarget kinase inhibitor, targets members of the mitogen-activated protein kinase (MAPK) pathway and VEGFR kinases. Here we assessed the association between expression of sorafenib targets and biomarkers of taxane sensitivity and response to therapy in pre-treatment tumors from patients enrolled in ECOG 2603, a phase III comparing sorafenib, carboplatin and paclitaxel (SCP) to carboplatin, paclitaxel and placebo (CP). Methods: Using a method of automated quantitative analysis (AQUA) of in situ protein expression, we quantified expression of VEGF-R2, VEGF-R1, VEGF-R3, FGF-R1, PDGF-Rβ, c-Kit, B-Raf, C-Raf, MEK1, ERK1/2, STMN1, MAP2, EB1 and Bcl-2 in pretreatment specimens from 263 patients. Results: An association was found between high FGF-R1 and VEGF-R1 and increased progression-free survival (PFS) and overall survival (OS) in our combined cohort (SCP and CP arms). Expression of FGF-R1 and VEGF-R1 was higher in patients who responded to therapy ((CR+PR) vs. (SD+PD+ un-evaluable)). Conclusions: In light of the absence of treatment effect associated with sorafenib, the association found between FGF-R1 and VEGF-R1 expression and OS, PFS and response might reflect a predictive biomarker signature for carboplatin/paclitaxel-based therapy. Seeing that carboplatin and pacitaxel are now widely used for this disease, corroboration in another cohort might enable us to improve the therapeutic ratio of this regimen. © 2013 Jilaveanu et al
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