16,601 research outputs found
Who Moves? Who Stays Put? Where's Home?
Analyzes results of a Pew Social & Demographic Trends survey on Americans' geographic mobility, including perceptions of "home," reasons for moving or staying, and economic considerations, by race/ethnicity, education, region, and other demographics
Lunar analogs of fluvial landscapes - Possible implications, 1 March 1968 - 1 February 1970
Geomorphic approach to possibility of fluid erosion on moo
Flight service evaluation of composite helicopter components
An assessment of composite helicopter structures, exposed to environmental effects, after four years of commercial service is presented. This assessment is supported by test results of helicopter components and test panels which have been exposed to environmental effects since late 1979. Full scale static and fatigue tests are being conducted on composite components obtained from S-76 helicopters in commercial operations in the Gulf Coast region of Louisiana. Small scale tests are being conducted on coupons obtained from panels being exposed to outdoor conditions in Stratford, Connecticut and West Palm Beach, Florida. The panel layups represent S-76 components. Moisture evaluations and strength tests are being conducted, on the S-76 components and panels, over a period of eight years. Results are discussed for components and panels with up to four years of exposure
K Giants in Baade's Window. II. The Abundance Distribution
This is the second in a series of papers in which we analyze spectra of over
400 K and M giants in Baade's Window, including most of the stars with proper
motions measured by Spaenhauer et al. [AJ, 103, 297 (1992)]. In our first
paper, we measured line--strength indices of Fe, Mg, CN and H and
calibrated them on the system of Faber et al. [ApJS, 57, 711 (1985)]. Here, we
use the index to derive an abundance distribution in
[Fe/H] for 322 stars with effective temperatures between 3900 K and 5160 K.
Our derived values of [Fe/H] agree well with those measured from
high--resolution echelle spectra (e.g., McWilliam \& Rich [ApJS, 91, 749
(1994)]) for the small number of stars in common. We find a mean abundance
for our sample of Baade's Window
K giants. More than half the sample lie in the range \feh\ .
We estimate line--of--sight distances for individual stars in our sample and
confirm that, in Baade's Window, most K giants with are foreground
disk stars, but the great majority (more than 80\%) with belong to the
bulge.
We also compare the metallicities derived from the CN and Mg indices to
those from iron. Most of the metal--rich stars in our sample appear to be
CN--weak, in contrast to the situation in metal--rich globular clusters and
elliptical galaxies. The metal--poor half of our sample ([Fe/H] ) shows
evidence for a mild Mg overenhancement ([Mg/Fe] ); but this is not
seen in the more metal--rich stars ([Fe/H] 0). The K giants in Baade's
Window therefore share some, but not all, of the characteristics of stars in
elliptical galaxies as inferred from their integrated light.Comment: Accepted for publication in the Astronomical Journal, tentatively
scheduled for July, 1996. LaTex source which generates 40 pages of text (no
figures or tables). Complete (text + 15 figs + 5 tables) preprint in gzip/tar
format is also available at
ftp://bessel.mps.ohio-state.edu/pub/terndrup/kg2.tar.gz (227 kbyte
Flight service evaluation of composite helicopter components
This first interim report presents the technical background for including environmental effects in the design of helicopter composite structures, and test results after approximately two year field exposure of components and panels. Composite structural components were removed from Sikorsky S-76 helicopters commercially operated in the Gulf Coast region of Louisiana. Fatigue tests were conducted for a graphite/epoxy tail rotor spar and static test for a graphite/epoxy and Kevlar/epoxy stabilizer. Graphite/epoxy and Kevlar/epoxy panels are being exposed to the outdoor environment in Stratford, Connecticut and West Palm Beach, Florida. For this reporting period the two year panels were returned, moisture measurements taken, and strength tests conducted. Results are compared with initial type certificate strengths for components and with initial laboratory coupon tests for the exposed panels. Comparisons are also presented with predicted and measured moisture contents
Substrate-specific clades of active marine methylotrophs associated with a phytoplankton bloom in a temperate coastal environment
Marine microorganisms that consume one-carbon (C1) compounds are poorly described, despite their impact on global climate via an influence on aquatic and atmospheric chemistry. This study investigated marine bacterial communities involved in the metabolism of C1 compounds. These communities were of relevance to surface seawater and atmospheric chemistry in the context of a bloom that was dominated by phytoplankton known to produce dimethylsulfoniopropionate. In addition to using 16S rRNA gene fingerprinting and clone libraries to characterize samples taken from a bloom transect in July 2006, seawater samples from the phytoplankton bloom were incubated with 13C-labeled methanol, monomethylamine, dimethylamine, methyl bromide, and dimethyl sulfide to identify microbial populations involved in the turnover of C1 compounds, using DNA stable isotope probing. The [13C]DNA samples from a single time point were characterized and compared using denaturing gradient gel electrophoresis (DGGE), fingerprint cluster analysis, and 16S rRNA gene clone library analysis. Bacterial community DGGE fingerprints from 13C-labeled DNA were distinct from those obtained with the DNA of the nonlabeled community DNA and suggested some overlap in substrate utilization between active methylotroph populations growing on different C1 substrates. Active methylotrophs were affiliated with Methylophaga spp. and several clades of undescribed Gammaproteobacteria that utilized methanol, methylamines (both monomethylamine and dimethylamine), and dimethyl sulfide. rRNA gene sequences corresponding to populations assimilating 13C-labeled methyl bromide and other substrates were associated with members of the Alphaproteobacteria (e.g., the family Rhodobacteraceae), the Cytophaga-Flexibacter-Bacteroides group, and unknown taxa. This study expands the known diversity of marine methylotrophs in surface seawater and provides a comprehensive data set for focused cultivation and metagenomic analyses in the future
New High Proper Motion Stars from the Digitized Sky Survey. II. Northern Stars with 0.5<mu<2.0 arcsec/yr at High Galactic Latitudes
In a continuation of our systematic search for high proper motion stars in
the Digitized Sky Survey, we have completed the analysis of northern sky fields
at galactic latitudes above 25 degrees. With the help of our SUPERBLINK
software, a powerful automated blink comparator developed by us, we have
identified 1146 stars in the magnitude range 8<r<20 with proper motions
0.500<mu<2.000 arcsec/yr. These include 1080 stars previously listed in
Luyten's proper motion catalogs (LHS, NLTT), 9 stars not previously listed in
the Luyten catalogs but reported elsewhere in the literature (including 1
previously reported by our team), and 57 new objects reported here for the
first time. This paper includes a list of positions, proper motions,
magnitudes, and finder charts for all the new high proper motion stars.
Combined with our previous study of low galactic latitude fields (see Paper I),
our survey now covers over 98% of the northern sky. We conclude that the Luyten
catalogs were 90% complete in the northern sky for stars with 0.5<mu<2.0
arcsec/yr down to magnitude r=19. We discuss the incompleteness of the old
Luyten proper motion survey, and estimate completeness limits for our new
survey.Comment: To appear in The Astronomical Journa
Comment to "Observation of the neutron radiative decay" by R.U. Khafizov et al., published in JETP Letters 83 (2006) 5 (Pis'ma v ZhETF 83 (2006) 7)
The commented manuscript was submitted for publication without informing at
least four of the other authors, viz. N. Severijns, O. Zimmer, H.-F. Wirth and
D. Rich. This violates our rights as collaborators. The analysis presented and
the manuscript itself have not been discussed and have also not been approved
by the entire collaboration prior to submission. Besides this formal
incorrectness, we also criticise the content of the paper
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