36,640 research outputs found
Some Applications of Detailed Wind Profile Data to Launch Vehicle Response Problems
The response of a launch vehicle to a number of detailed wind profiles has been determined. The wind profiles were measured by two techniques which are briefly described. One of these techniques uses an angle-of-attack sensor in conjunction with guidance data to measure the wind profile traversed by some particular launch vehicle. The other wind-measuring technique is a photographic triangulation method, whereby two cameras take simultaneous pictures of a vertical trail of smoke left by a launch vehicle or sounding rocket. The response of a vehicle flying these detailed profiles is compared with the response of the same vehicle flying through balloon-measured profiles. The response to the detailed wind profiles, relative t o the balloon-measured profiles, is characterized by the large excitation of the rigid pitch and elastic bending modes. This is found to cause higher loads on the launch vehicle structure. Established design criteria which utilize balloon measured wind profiles have arbitrarily accounted-for this increased load by adding a load due to some type of discrete gust
Simultaneous polymerization and molding of Pyrrone polymers
Simultaneous polymerization and hot pressing of Pyrrone polymer
Space Telescope Imaging Spectrograph Parallel Observations of the Planetary Nebula M94-20
The planetary nebula M94--20 in the Large Magellanic Cloud was
serendipitously observed with the Space Telescope Imaging Spectrograph on board
the Hubble Space Telescope as part of the Hubble Space Telescope Archival Pure
Parallel Program. We present spatially resolved imaging and spectral data of
the nebula and compare them with ground based data, including detection of
several emission lines from the nebula and the detection of the central star.
We find the total H alpha + [NII] flux = 7.3e-15 erg s^-1 cm^-2 and we estimate
the magnitude of the central star to be m_V = 26.0 +/- 0.2. Many other H alpha
sources have been found in M31, M33 and NGC 205 as well. We discuss the use of
the parallel observations as a versatile tool for planetary nebula surveys and
for other fields of astronomical research.Comment: Latex, 14 pages, 2 JPEG figures, 2 tables. PASP Research Note, June
1999, in pres
Determination of arginase: estimation of citrulline
Determination of arginase: estimation of citrullin
Acetyl-ornithine transaminase in Neurospora
Acetyl-ornithine transaminase in Neurospor
Discovery of pulsations in the X-ray transient 4U 1901+03
We describe observations of the 2003 outburst of the hard-spectrum X-ray
transient 4U 1901+03 with the Rossi X-ray Timing Explorer. The outburst was
first detected in 2003 February by the All-Sky Monitor, and reached a peak
2.5-25 keV flux of 8x10^-9 ergs/cm^2/s (around 240 mCrab). The only other known
outburst occurred 32.2 yr earlier, likely the longest presently known
recurrence time for any X-ray transient. Proportional Counter Array (PCA)
observations over the 5-month duration of the 2003 outburst revealed a 2.763 s
pulsar in a 22.58 d orbit. The detection of pulsations down to a flux of
3x10^-11 ergs/cm^2/s (2.5-25 keV), along with the inferred long-term accretion
rate of 8.1x10^-11 M_sun/yr (assuming a distance of 10 kpc) suggests that the
surface magnetic field strength is below ~5x10^11 G. The corresponding
cyclotron energy is thus below 4 keV, consistent with the non-detection of
resonance features at high energies. Although we could not unambiguously
identify the optical counterpart, the lack of a bright IR candidate within the
1' RXTE error circle rules out a supergiant mass donor. The neutron star in 4U
1901+03 probably accretes from the wind of a main-sequence O-B star, like most
other high-mass binary X-ray pulsars. The almost circular orbit e=0.036
confirms the system's membership in a growing class of wide, low-eccentricity
systems in which the neutron stars may have received much smaller kicks as a
result of their natal supernova explosions.Comment: 7 pages, 6 figures, accepted by ApJ. Very minor addition in response
to referee's comment; updated author affiliatio
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Identification of Trace Organic Components in the CR Chondrites by 4D TOFMS
This paper reports preliminary results of a 4D TOFMS study of CR chondrite organic material, highlighting the low-level organic species that may further reveal the complexity of parent body modification of interstellar precursors
Anchoring In Action: Manual Estimates Of Slant Are Powerfully Biased Toward Initial Hand Orientation And Are Correlated With Verbal Report
People verbally overestimate hill slant by approximately 15 degrees to 25 degrees, whereas manual estimates (e. g., palm board measures) are thought to be more accurate. The relative accuracy of palm boards has contributed to the widely cited theoretical claim that they tap into an accurate, but unconscious, motor representation of locomotor space. In the current work, 4 replications (total N = 204) carried out by 2 different laboratories tested an alternative anchoring hypothesis that manual action measures give low estimates because they are always initiated from horizontal. The results of all 4 replications indicate that the bias from response anchoring can entirely account for the difference between manual and verbal estimates. Moreover, consistent correlations between manual and verbal estimates given by the same observers support the conclusion that both measures are based on the same visual representation. Concepts from the study of judgment under uncertainty apply even to action measures in information rich environments
Prevalence and clinical characteristics of left ventricular dysfunction among elderly patients in general practice setting: cross sectional survey
Objective: To assess the prevalence and clinical characteristics of left ventricular dysfunction among elderly patients in the general practice setting by echocardiographic assessment of ventricular function.
Design: Cross sectional survey.
Setting: Four centre general practice in Poole, Dorset.
Subjects: 817 elderly patients aged 70-84 years.
Main outcomes: Echocardiographic assessment of left ventricular systolic function including measurement of ejection fraction by biplane summation method where possible, clinical symptoms, and signs of left ventricular dysfunction.
Results: The overall prevalence of left ventricular systolic dysfunction was 7.5% (95% confidence interval 5.8% to 9.5%); mild dysfunction (5.0%) was considerably more prevalent than moderate (1.6%) or severe dysfunction (0.7%). Measurement of ejection fraction was possible in 82% of patients (n=667): in patients categorised as having mild, moderate, or severe dysfunction, the mean ejection fraction was 48% (SD 12.0), 38% (8.1), and 26% (7.9) respectively. At all ages the prevalence was much higher in men than in women (odds ratio 5.1, 95% confidence interval 2.6 to 10.1). No clinical symptom or sign was both sensitive and specific. In around half the patients with ventricular dysfunction (52%, 32/61) heart failure had not been previously diagnosed.
Conclusions: Unrecognised left ventricular dysfunction is a common problem in elderly patients in the general practice setting. Appropriate treatment with angiotensin converting enzyme inhibitors has the potential to reduce hospitalisation and mortality in these patients, but diagnosis should not be based on clinical history and examination alone. Screening is feasible in general practice, but it should not be implemented until the optimum method of identifying left ventricular dysfunction is clarified, and the cost effectiveness of screening has been shown
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