4,267 research outputs found

    Overview of safety research

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    Aircraft safety is reviewed by first establishing a perspective of air transportation accidents as a function of calendar year, geographic area, and phase of flight, and then by describing the threats to safety and NASA research underway in the three representative areas of engine operational problems, meteorological phenomena, and fire. Engine rotor burst protection, aircraft nacelle fire extinguishment, the aircraft-weather interface, severe weather wind shears and turbulence, clear air turbulence, and lightning are among the topics covered. Fire impact management through fire resistant materials technology development is emphasized

    NASA technical advances in aircraft occupant safety

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    NASA's aviation safety technology program examines specific safety problems associated with atmospheric hazards, crash-fire survival, control of aircraft on runways, human factors, terminal area operations hazards, and accident factors simulation. While aircraft occupants are ultimately affected by any of these hazards, their well-being is immediately impacted by three specific events: unexpected turbulence encounters, fire and its effects, and crash impact. NASA research in the application of laser technology to the problem of clear air turbulence detection, the development of fire resistant materials for aircraft construction, and to the improvement of seats and restraint systems to reduce crash injuries are reviewed

    Summary report of the General Services Committee

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    The discussions addressed meteorological services in terms of: (1) assessment of adequacies of present services; (2) acquisition and processing of data not now available, but deemed vital to improvement of the aviation system; and (3) delivery of an adequate meteorological service to various users within the National Aviation System, yet responsive to changing system requirements. Other discussions included meteorological information, training and personnel, and research needs and responsibilities

    Gauchos and ochos: a Wee1-Cdk tango regulating mitotic entry

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    The kinase Wee1 has been recognized for a quarter century as a key inhibitor of Cyclin dependent kinase 1 (Cdk1) and mitotic entry in eukaryotes. Nonetheless, Wee1 regulation is not well understood and its large amino-terminal regulatory domain (NRD) has remained largely uncharted. Evidence has accumulated that cyclin B/Cdk1 complexes reciprocally inhibit Wee1 activity through NRD phosphorylation. Recent studies have identified the first functional NRD elements and suggested that vertebrate cyclin A/Cdk2 complexes also phosphorylate the NRD. A short NRD peptide, termed the Wee box, augments the activity of the Wee1 kinase domain. Cdk1/2-mediated phosphorylation of the Wee box (on T239) antagonizes kinase activity. A nearby region harbors a conserved RxL motif (RxL1) that promotes cyclin A/Cdk2 binding and T239 phosphorylation. Mutation of either T239 or RxL1 bolsters the ability of Wee1 to block mitotic entry, consistent with negative regulation of Wee1 through these sites. The region in human somatic Wee1 that encompasses RxL1 also binds Crm1, directing Wee1 export from the nucleus. These studies have illuminated important aspects of Wee1 regulation and defined a specific molecular pathway through which cyclin A/Cdk2 complexes foster mitotic entry. The complexity, speed, and importance of regulation of mitotic entry suggest that there is more to be learned

    Use of aircraft for zero-gravity environment

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    Use of aircraft as test vehicle to produce zero gravity or weightlessness environmen

    Summary Proceedings of a Wind Shear Workshop

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    A number of recent program results and current issues were addressed: the data collection phase of the highly successful Joint Airport Weather Study (JAWS) Project and the NASA-B5f7B Gust Gradient Program, the use of these data for flight crew training through educational programs (e.g., films) and with manned flight training simulators, methods for post-accident determination of wind conditions from flight data recorders, the microburst wind shear phenomenon which was positively measured and described the ring vortex as a possible generating mechanism, the optimum flight procedure for use during an unexpected wind shear encounter, evaluation of the low-level wind shear alert system (LLWSAS), and assessment of the demonstrated and viable application of Doppler radar as an operational wind shear warning and detection system

    How Do Tourists React to Political Violence? An Empirical Analysis of Tourism in Egypt

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    This paper uses a detailed database of political violence in Egypt to study European and US tourists' attitudes towards a conflict region. We study the heterogeneous impacts of different dimensions of political violence and counter-violence on tourist flows to Egypt in the 1990s. Both US and EU tourists respond negatively to attacks on tourists, but are not influenced by casualties arising in confrontations between domestic groups. However, European tourists are sensitive to the counter-violence measures implemented by the Egyptian government. There is also evidence of arrivals of tourists into Egypt rising when fatalities in the Israeli/Palestinian conflict increase.</p
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