7,782 research outputs found
High-speed civil transport flight- and propulsion-control technological issues
Technology advances required in the flight and propulsion control system disciplines to develop a high speed civil transport (HSCT) are identified. The mission and requirements of the transport and major flight and propulsion control technology issues are discussed. Each issue is ranked and, for each issue, a plan for technology readiness is given. Certain features are unique and dominate control system design. These features include the high temperature environment, large flexible aircraft, control-configured empennage, minimizing control margins, and high availability and excellent maintainability. The failure to resolve most high-priority issues can prevent the transport from achieving its goals. The flow-time for hardware may require stimulus, since market forces may be insufficient to ensure timely production. Flight and propulsion control technology will contribute to takeoff gross weight reduction. Similar technology advances are necessary also to ensure flight safety for the transport. The certification basis of the HSCT must be negotiated between airplane manufacturers and government regulators. Efficient, quality design of the transport will require an integrated set of design tools that support the entire engineering design team
Restructuring Programming Instruction in the Computer Information Systems Curriculum: One Department\u27s Approach
The rationale for and details of one Computer Information Systems (CIS) department\u27s plans for a drastic restructuring of the CIS curriculum are presented. The proposed approach is compared with current and developing model curricula for both computer science (CS) and computer information systems programs. The new curriculum\u27s approach to information systems construction is characterized by delivering training in the use of fourth generation development tools, the assembly of software components, event-driven programming and client/server practices. The development tools, the programming environment and the client interface are all equipped with a graphical user interface (GUI)
Deletion of Tsc2 in nociceptors reduces target innervation, ion channel expression, and sensitivity to heat
AbstractThe mechanistic target of rapamycin complex 1 (mTORC1) is known to regulate cellular growth pathways, and its genetic activation is sufficient to enhance regenerative axon growth following injury to the central or peripheral nervous systems. However, excess mTORC1 activation may promote innervation defects, and mTORC1 activity mediates injury-induced hypersensitivity, reducing enthusiasm for the pathway as a therapeutic target. While mTORC1 activity is required for full expression of some pain modalities, the effects of pathway activation on nociceptor phenotypes and sensory behaviors are currently unknown. To address this, we genetically activated mTORC1 in mouse peripheral sensory neurons by conditional deletion of its negative regulator Tuberous Sclerosis Complex 2 (Tsc2). Consistent with the well-known role of mTORC1 in regulating cell size, soma size and axon diameter of C-nociceptors were increased in Tsc2-deleted mice. Glabrous skin and spinal cord innervation by C-fiber neurons were also disrupted. Transcriptional profiling of nociceptors enriched by fluorescence-associated cell sorting (FACS) revealed downregulation of multiple classes of ion channels as well as reduced expression of markers for peptidergic nociceptors in Tsc2-deleted mice. In addition to these changes in innervation and gene expression, Tsc2-deleted mice exhibited reduced noxious heat sensitivity and decreased injury-induced cold hypersensitivity, but normal baseline sensitivity to cold and mechanical stimuli. Together, these data show that excess mTORC1 activity in sensory neurons produces changes in gene expression, neuron morphology and sensory behavior.</jats:p
The Compositional C++ Language Definition
This document gives a concise definition of the syntax and semantics of CC++. Knowledge of the C++ language definition and the C++ language reference manual is assumed
Constrained Curve Fitting
We survey techniques for constrained curve fitting, based upon Bayesian
statistics, that offer significant advantages over conventional techniques used
by lattice field theorists.Comment: Lattice2001(plenary); plenary talk given by G.P. Lepage at Lattice
2001 (Berlin); 9 pages, 5 figures (postscript specials
Voltage-independent SK-channel dysfunction causes neuronal hyperexcitability in the hippocampus of Fmr1 knock-out mice
Neuronal hyperexcitability is one of the major characteristics of fragile X syndrome (FXS), yet the molecular mechanisms of this critical dysfunction remain poorly understood. Here we report a major role of voltage-independent potassium (
A Deeper Look at the New Milky Way Satellites: Sagittarius II, Reticulum II, Phoenix II, and Tucana III
We present deep Magellan/Megacam stellar photometry of four recently
discovered faint Milky Way satellites: Sagittarius II (Sgr II), Reticulum II
(Ret II), Phoenix II (Phe II), and Tucana III (Tuc III). Our photometry reaches
~2-3 magnitudes deeper than the discovery data, allowing us to revisit the
properties of these new objects (e.g., distance, structural properties,
luminosity measurements, and signs of tidal disturbance). The satellite
color-magnitude diagrams show that they are all old (~13.5 Gyr) and metal-poor
([Fe/H]). Sgr II is particularly interesting as it sits in an
intermediate position between the loci of dwarf galaxies and globular clusters
in the size-luminosity plane. The ensemble of its structural parameters is more
consistent with a globular cluster classification, indicating that Sgr II is
the most extended globular cluster in its luminosity range. The other three
satellites land directly on the locus defined by Milky Way ultra-faint dwarf
galaxies of similar luminosity. Ret II is the most elongated nearby dwarf
galaxy currently known for its luminosity range. Our structural parameters for
Phe II and Tuc III suggest that they are both dwarf galaxies. Tuc III is known
to be associated with a stellar stream, which is clearly visible in our
matched-filter stellar density map. The other satellites do not show any clear
evidence of tidal stripping in the form of extensions or distortions. Finally,
we also use archival HI data to place limits on the gas content of each object.Comment: Accepted for publication in ApJ. Minor updates to match accepted
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Deconvolution of pro- and antiviral genomic responses in Zika virus-infected and bystander macrophages.
Genome-wide investigations of host-pathogen interactions are often limited by analyses of mixed populations of infected and uninfected cells, which lower sensitivity and accuracy. To overcome these obstacles and identify key mechanisms by which Zika virus (ZIKV) manipulates host responses, we developed a system that enables simultaneous characterization of genome-wide transcriptional and epigenetic changes in ZIKV-infected and neighboring uninfected primary human macrophages. We demonstrate that transcriptional responses in ZIKV-infected macrophages differed radically from those in uninfected neighbors and that studying the cell population as a whole produces misleading results. Notably, the uninfected population of macrophages exhibits the most rapid and extensive changes in gene expression, related to type I IFN signaling. In contrast, infected macrophages exhibit a delayed and attenuated transcriptional response distinguished by preferential expression of IFNB1 at late time points. Biochemical and genomic studies of infected macrophages indicate that ZIKV infection causes both a targeted defect in the type I IFN response due to degradation of STAT2 and reduces RNA polymerase II protein levels and DNA occupancy, particularly at genes required for macrophage identity. Simultaneous evaluation of transcriptomic and epigenetic features of infected and uninfected macrophages thereby reveals the coincident evolution of dominant proviral or antiviral mechanisms, respectively, that determine the outcome of ZIKV exposure
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