15,058 research outputs found
Molecular Identifications in Experiments with Astronomical Ice Analogues: New Data, Old Strategies, and the N2 + Acetone System
A recent publication on the radiation chemistry and IR spectroscopy of N2 plus acetone ices is used to illustrate some of the difficulties encountered in the study of astronomical ice analogues. Concerns and problems are identified and suggestions for their solution are presented, including new infrared (IR) spectra of amorphous ices. The hazards of using peak positions alone for assignments of the IR spectra of irradiated ices are illustrated, and the importance of considering the underlying reaction chemistry is shown. Several experiments are proposed as a way to investigate the behaviour of acetone in cold, extraterrestrial environments. Electronic versions of IR spectra are provided and several new refractive indices of ices are reported
THE PRICING EFFICIENCY OF AGRICULTURAL FUTURES MARKETS: AN ANALYSIS OF PREVIOUS RESEARCH RESULTS
The analysis examines quantitatively the findings of previous studies of the pricing efficiency of various agricultural markets using a logit framework. The findings provide insight into the importance of commodity characteristics, uncertainty, and testing procedures used on the results of past research of pricing efficiency. The study also identifies several areas for further research.Demand and Price Analysis,
Preliminary results of the University of California X-ray experiment on the OSO-3
Cosmic and solar X ray data obtained by Orbiting Solar Observatory /OSO-3
Song Lyric Sheet, Ellsworth\u27s Avengers, 1861
This song lyric sheet of Ellsworth\u27s Avengers, features illustrations of cherubs along the top, a woman along the left edge, a man holding a musical instrument on the right edge, and leafy vines. The author of the lyrics is named below the song title. The publisher is printed at the bottom of the page among the illustrations.https://scholarsjunction.msstate.edu/fvw-manuscripts-original-manuscripts/1275/thumbnail.jp
Large-scale cosmic flows and moving dark energy
Large-scale matter bulk flows with respect to the cosmic microwave background
have very recently been detected on scales 100 Mpc/h and 300 Mpc/h by using two
different techniques showing an excellent agreement in the motion direction.
However, the unexpectedly large measured amplitudes are difficult to understand
within the context of standard LCDM cosmology. In this work we show that the
existence of such a flow could be signaling the presence of moving dark energy
at the time when photons decoupled from matter. We also comment on the relation
between the direction of the CMB dipole and the preferred axis observed in the
quadrupole in this scenario.Comment: 11 pages, 2 figures. New comments and references included. Final
version to appear in JCA
Galaxy Distances in the Nearby Universe: Corrections For Peculiar Motions
By correcting the redshift--dependent distances for peculiar motions through
a number of peculiar velocity field models, we recover the true distances of a
wide, all-sky sample of nearby galaxies (~ 6400 galaxies with velocities
cz<5500 km/s), which is complete up to the blue magnitude B=14 mag. Relying on
catalogs of galaxy groups, we treat ~2700 objects as members of galaxy groups
and the remaining objects as field galaxies.
We model the peculiar velocity field using: i) a cluster dipole
reconstruction scheme; ii) a multi--attractor model fitted to the Mark II and
Mark III catalogs of galaxy peculiar velocities. According to Mark III data the
Great Attractor has a smaller influence on local dynamics than previously
believed, whereas the Perseus-Pisces and Shapley superclusters acquire a
specific dynamical role. Remarkably, the Shapley structure, which is found to
account for nearly half the peculiar motion of the Local Group, is placed by
Mark III data closer to the zone of avoidance with respect to its optical
position.
Our multi--attractor model based on Mark III data favors a cosmological
density parameter Omega ~ 0.5 (irrespective of a biasing factor of order
unity). Differences among distance estimates are less pronounced in the ~ 2000
- 4000 km/s distance range than at larger or smaller distances. In the last
regions these differences have a serious impact on the 3D maps of the galaxy
distribution and on the local galaxy density --- on small scales.Comment: 24 pages including (9 eps figures and 7 tables). Figures 1,2,3,4 are
available only upon request. Accepted by Ap
Radiolysis of Amino Acids in Outer Solar-System Ice Analogs
Amino acids have been found in cometary dust particles and in the organic component of meteorites. These molecules, important for pre-biotic chemistry and for active biological systems, might be formed in cold planetary or interstellar environments and then delivered to H20-rich surfaces in the outer solar system. Many models for the availability of organic species on Earth and elsewhere depend on the ability of these molecules to survive in radiation-rich space environments. This poster presents results of O.8-MeV proton radiolysis of ice films at lS-140K. using infrared spectroscopy, the destruction rates of glycine, alanine, and phenylalanine have been determined for both pure films and those containing amino acids diluted in H2o. our results are discussed in terms of the survivability of these molecules in the icy surfaces present in the outer solar system and the possibility of their detection by instruments on board the New Horizons spacecraf
- …