20,242 research outputs found
Publications of the planetary biology program for 1976: A special bibliography
An annual listing of current publications resulting from research pursued under the auspices of NASA's Planetary Biology Program is presented. To stimulate the exchange of information and ideas among scientists working in the different areas of the program. To facilitate the exchange process. The author of each publication who is presently participating in the program is identified by asterisk. Current addresses for all principal investigators are given in the appendix
Scientific publications and presentations relating to planetary quarantine. Volume 5: The 1971 supplement
A bibliographic compilation, with approximately 200 listings, on planetary quarantine is presented. Also given are scientific publications, and presentations along with an author index
Scientific publications and presentations relating to planetary quarantine. Volume 5: The 1972 supplement
The sixth annual supplement to the bibliography on planetary quarantine contains 191 references, an author index and a permuted title index
The Late Time Light Curve of SN 1998bw Associated with GRB980425
We report 139 photometric observations through the B, V, and I filters of the
supernova SN 1998bw, an object which is associated with the Gamma-Ray Burst GRB
980425. Detailed light curves of this unique supernova can be compared to
theoretical models, so we report here our light curve for 123 days between 27
June 1998 and 28 October 1998. The light curve of SN 1988bw is consistent with
those of the Type Ic class. We find that the magnitude-versus-time relation for
this supernova is linear to within 0.05 mags in all colors over the entire
duration of our study. Our measured uniform decline rates are , , and magnitudes per day in the
B, V, and I bands. The linear decline and the rate of that decline suggest that
late time light curve is powered by the radioactive decay of cobalt with some
leakage of the gamma rays.Comment: 15 pages, 1 figure, 1 table, Accepted for publication in PAS
Widely wavelength-selective Al2O3:Er3+ ring laser
Integrated Al2O3:Er3+ channel waveguide ring lasers were realized on thermally oxidized silicon substrates. High pump power coupling into- and low output power coupling from the ring is achieved in a straightforward design. Wavelength\ud
selection in the range 1532 to 1557 nm was demonstrated by\ud
varying the length of the output coupler from the ring
Evidence for High-Frequency QPOs with a 3:2 Frequency Ratio from a 5000 Solar Mass Black Hole
Following the discovery of 3:2 resonance quasi-periodic oscillations (QPOs)
in M82X-1 (Pasham et al. 2014), we have constructed power density spectra (PDS)
of all 15 (sufficiently long) {\it XMM-Newton} observations of the
ultraluminous X-ray source NGC1313X-1 ( 210
erg/sec). We detect a strong QPO at a frequency of 0.290.01 Hz in data
obtained on 2012 December 16. Subsequent searching of all the remaining
observations for a 3:2/2:3 frequency pair revealed a feature at 0.460.02
Hz on 2003 Dec 13 (frequency ratio of 1.590.09). The global significance
of the 0.29 Hz feature considering all frequencies between 0.1 and 4 Hz is
3.5 . The significance of the 0.460.02 Hz QPO is 3.5
for a search at 2/3 and 3/2 of 0.29 Hz. We also detect lower frequency QPOs
(32.92.6 and 79.71.2 mHz). All the QPOs are super-imposed on a
continuum consisting of flat-topped, band-limited noise, breaking into a
power-law at a frequency of 163 mHz and white noise at 0.1 Hz.
NGC1313X-1's PDS is analogous to stellar-mass black holes' (StMBHs) PDS in the
so-called steep power-law state, but with the respective frequencies (both QPOs
and break frequencies) scaled down by a factor of 1000. Using the
inverse mass-to-high-frequency QPO scaling of StMBHs, we estimate NGC1313X-1's
black hole mass to be 50001300 , consistent with an inference
from the scaling of the break frequency. However, the implied Eddington ratio,
L 0.030.01, is significantly lower compared to StMBHs in the
steep power-law state (L 0.2).Comment: Published in ApJ Letter
Feasibility study of the transonic biplane concept for transport aircraft application
Investigations were conducted to evaluate the feasibility of a transonic biplane consisting of a forward-mounted swept-back lower wing, a rear-mounted swept-forward upper wing, and a vertical fin connecting the wings at their tips. This wing arrangement results in significant reductions in induced drag relative to a monoplane designed with the same span, and it allows for a constant-section fuselage shape while closely matching an ideal area distribution curve for M = 0.95 cruise. However, no significant reductions in ramp weight were achieved for the biplane relative to a monoplane with the same mission capability. Flutter analyses of the biplane revealed both symmetric and antisymmetric instabilities that occur well below the required flutter speed. Further studies will be required to determine if acceptable flutter speeds can be achieved through the elimination of the instabilities by passive means or by active controls. Configurations designed for other missions, especially those with lower Mach numbers and lower dynamic pressures, should be examined since the geometries suitable for those design constraints might avoid the weight penalties and flutter instabilities which prevent exploitation of induced drag benefits for the configuration studied
A -adic RanSaC algorithm for stereo vision using Hensel lifting
A -adic variation of the Ran(dom) Sa(mple) C(onsensus) method for solving
the relative pose problem in stereo vision is developped. From two 2-adically
encoded images a random sample of five pairs of corresponding points is taken,
and the equations for the essential matrix are solved by lifting solutions
modulo 2 to the 2-adic integers. A recently devised -adic hierarchical
classification algorithm imitating the known LBG quantisation method classifies
the solutions for all the samples after having determined the number of
clusters using the known intra-inter validity of clusterings. In the successful
case, a cluster ranking will determine the cluster containing a 2-adic
approximation to the "true" solution of the problem.Comment: 15 pages; typos removed, abstract changed, computation error remove
Momentum distribution of confined bosons: temperature dependence
The momentum distribution function of a parabolically confined gas of bosons
with harmonic interparticle interactions is derived. In the Bose-Einstein
condensation region, this momentum distribution substantially deviates from a
Maxwell-Boltzmann distribution. It is argued that the determination of the
temperature of the boson gas from the Bose-Einstein momentum distribution
function is more appropriate than the currently used fitting to the high
momentum tail of the Maxwell-Boltzmann distribution.Comment: 5 REVTEX pages + 2 postscript figures. Accepted in Phys. Rev.
- …