724 research outputs found
Wind Data From Radar Echoes
Series statement on cover: "Technical Report no. 1"Listed in ISWS Publications Catalog (1995, p. 14) as Contract Report no. 1, with the series statement Technical Report no. 1 included in the citation.published or submitted for publicationis peer reviewedOpe
Utilization of Radar in Short-range Weather Forecasting: Final Report
published or submitted for publicationis peer reviewedOpe
Validation of the Passenger Ride Quality Apparatus (PRQA) for simulation of aircraft motions for ride-quality research
The NASA passenger ride quality apparatus (PRQA), a ground based motion simulator, was compared to the total in flight simulator (TIFS). Tests were made on PRQA with varying stimuli: motions only; motions and noise; motions, noise, and visual; and motions and visual. Regression equations for the tests were obtained and subsequent t-testing of the slopes indicated that ground based simulator tests produced comfort change rates similar to actual flight data. It was recommended that PRQA be used in the ride quality program for aircraft and that it be validated for other transportation modes
The effect of operations on the ground noise footprints associated with a large multibladed, nonbanging helicopter
In order to expand the data base of helicopter external noise characteristics, a flyover noise measurement program was conducted utilizing the NASA Civil Helicopter Research Aircraft. The remotely operated multiple array acoustics range (ROMAAR) and a 2560-m linear microphone array were utilized for the purpose of documenting the noise characteristics of the test helicopter during flyby and landing operations. By utilizing both ROMAAR concept and the linear array, the data necessary to plot the ground noise footprints and noise radiation patterns were obtained. Examples of the measured noise signature of the test helicopter, the ground noise footprint or contours, and the directivity patterns measured during level flyby and landing operations of a large, multibladed, nonbanging helicopter, the CH-53, are presented
The Carrington event not observed in most ice core nitrate records
The Carrington Event of 1859 is considered to be among the largest space weather events of the last 150 years. We show that only one out of 14 well-resolved ice core records from Greenland and Antarctica has a nitrate spike dated to 1859. No sharp spikes are observed in the Antarctic cores studied here. In Greenland numerous spikes are observed in the 40 years surrounding 1859, but where other chemistry was measured, all large spikes have the unequivocal signal, including co-located spikes in ammonium, formate, black carbon and vanillic acid, of biomass burning plumes. It seems certain that most spikes in an earlier core, including that claimed for 1859, are also due to biomass burning plumes, and not to solar energetic particle (SEP) events. We conclude that an event as large as the Carrington Event did not leave an observable, widespread imprint in nitrate in polar ice. Nitrate spikes cannot be used to derive the statistics of SEPs
Characterization of queen specific components of the fluid released by fighting honey bee queens
Swarming honey bee (Apis mellifera L.) colonies rear supernumerary young queens that compete for the limited resources (workers) necessary for founding a new colony. Young queens often fight to death. Queens show several adaptations to fight and conflict, such as short developmental time and early onset of venom production. During fights, queens often release rectal fluid with a strong smell of wine grapes, after which they temporarily stop fighting. This potentially reduces individual overall risk of deadly injury. The fluid and one of its components, ortho-aminoacetophenone, were previously found to have a pheromonal effect on workers, but the evidence is equivocal. Recently, it has been suggested that the effects of this substance may be context- or concentration-specific. We performed semi-quantitative gas-chromatography mass spectrometry (GC/MS) analysis of the fluid (1) released by queens during their first fight, (2) released during a subsequent fight, and (3) obtained by dissecting the hindgut of queens and (4) of workers. Following preliminary results by Page et al. 1988 (Experientia 44: 270-271), we scored presence / absence of eight substances. Five substances (ortho-aminoacetophenone, decanoic acid, dodecanoic acid, octyl decanoate, and decyl decanoate) were characteristic of queens only. ortho-Aminoacetophenone was detected in all queen and in none of the worker samples, in agreement with previous findings that worker faeces do not have any pheromonal effect. The fluid released by queens on their second fight also contained ortho-aminoacetophenone, but in smaller quantities. These data substantiate previous bioassay results, and provide estimates of ortho-aminoacetophenone concentration as required to design experiments addressing the function and adaptive significance of this behaviour
Comment on “Low time resolution analysis of ice cores cannot detect impulsive nitrate events” by D. F. Smart et al.
Smart et al. (2014) suggested that the detection of nitrate spikes in polar ice cores from solar energetic particle (SEP) events could be achieved if an analytical system with sufficiently high resolution was used. Here we show that the spikes they associate with SEP events are not reliably recorded in cores from the same location, even when the resolution is clearly adequate. We explain the processes that limit the effective resolution of ice cores. Liquid conductivity data suggest that the observed spikes are associated with sodium or another nonacidic cation, making it likely that they result from deposition of sea salt or similar aerosol that has scavenged nitrate, rather than from a primary input of nitrate in the troposphere. We consider that there is no evidence at present to support the identification of any spikes in nitrate as representing SEP events. Although such events undoubtedly create nitrate in the atmosphere, we see no plausible route to using nitrate spikes to document the statistics of such events
Messenger RNAs localized to distal projections of human stem cell derived neurons
The identification of mRNAs in distal projections of model organisms has led to the discovery of multiple proteins that are locally synthesized for functional roles such as axon guidance, injury signaling and regeneration. The extent to which local protein synthesis is conserved in human neurons is unknown. Here we used compartmentalized microfluidic chambers to characterize the transcriptome of distal projections of human embryonic stem cells differentiated using a protocol which enriched for glutamatergic neurons (hESC-neurons). Using gene expression analysis, we identified mRNAs proportionally enriched in these projections, representing a functionally unique local transcriptome as compared to the human neuronal transcriptome inclusive of somata. Further, we found that the most abundant mRNAs within these hESC-neuron projections were functionally similar to the axonal transcriptome of rat cortical neurons. We confirmed the presence of two well characterized axonal mRNAs in model organisms, β-actin and GAP43, within hESC-neuron projections using multiplexed single molecule RNA-FISH. Additionally, we report the novel finding that oxytocin mRNA localized to these human projections and confirmed its localization using RNA-FISH. This new evaluation of mRNA within human projections provides an important resource for studying local mRNA translation and has the potential to reveal both conserved and unique translation dependent mechanisms
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