6,845 research outputs found
Observations of vertical velocity power spectra with the SOUSY VHF radar
A data set taken with the SOUSY VHF radar from October 28 to November 13, 1981 was used to calculate the power spectrum of the vertical velocities directly from the vertical beam measurements. The spectral slopes for the frequency spectra have been determined out to periods of several days and have been found to have values near -1 in the troposphere and shallower slopes in the lower stratosphere. The value of -1 is in agreement with the value found by Larsen et al. (1985) and Balsley and Carter (1982) in the range from a few minutes to 1 hr
Botanicals as part of an integrated value-added pork production system
Some herbs are known to exhibit natural antimicrobial activity and other characteristics that could be useful in value-added animal production. Four botanical products were tested for possible inclusion in swine feeds as alternatives to synthetic chemotherapeutic and antimicrobial agents
Genetic diversity at the FMR1 locus in the Indonesian population
We report an analysis of allelic diversity at short tandem repeat polymorphisms within the fragile XA locus in 1069 male volunteers from twelve Indonesian sub-populations. An odd numbered allele of DXS548 was found at high frequency in all Indonesian populations. Greater allelic diversity was identified at the loci under study than has been previously reported for an Asian population. These differences distinguish the Indonesian population from all previously reported Asian, European and African populations. A high frequency of small premutation alleles, 4/120 (3.3%, 95% CI 0.9–8.3%), was identified in the Moluccan population of Hiri Island
UHF and VHF radar observations of thunderstorms
A study of thunderstorms was made in the Summer of 1985 with the 430-MHz and 50-MHz radars at the Arecibo Observatory in Puerto Rico. Both radars use the 300-meter dish, which gives a beam width of less than 2 degrees even at these long wavelengths. Though the radars are steerable, only vertical beams were used in this experiment. The height resolution was 300 and 150 meters for the UHF and VHF, respectively. Lightning echoes, as well as returns from precipitation and clear-air turbulence were detected with both wavelengths. Large increases in the returned power were found to be coincident with increasing downward vertical velocities at UHF, whereas at VHF the total power returned was relatively constant during the life of a storm. This was attributed to the fact that the VHF is more sensitive to scattering from the turbulence-induced inhomogeneities in the refractive index and less sensitive to scatter from precipitation particles. On occasion, the shape of the Doppler spectra was observed to change with the occurrence of a lightning discharge in the pulse volume. Though the total power and mean reflectivity weighted Doppler velocity changed little during these events, the power is Doppler frequency bins near that corresponding to the updraft did increase substantially within a fraction of a second after a discharge was detected in the beam. This suggests some interaction between precipitation and lightning
The Evolution of the Field and Cluster Morphology-Density Relation for Mass-Selected Samples of Galaxies
The Sloan Digital Sky Survey (SDSS) and photometric/spectroscopic surveys in
the GOODS-South field (the Chandra Deep Field-South, CDFS) are used to
construct volume-limited, stellar mass-selected samples of galaxies at
redshifts 0<z<1. The CDFS sample at 0.6<z<1.0 contains 207 galaxies complete
down to M=4x10^10 Msol (for a ``diet'' Salpeter IMF), corresponding to a
luminosity limit for red galaxies of M_B=-20.1. The SDSS sample at
0.020<z<0.045 contains 2003 galaxies down to the same mass limit, which
corresponds to M_B=-19.3 for red galaxies. Morphologies are determined with an
automated method, using the Sersic parameter n and a measure of the residual
from the model fits, called ``bumpiness'', to distinguish different
morphologies. These classifications are verified with visual classifications.
In agreement with previous studies, 65-70% of the galaxies are located on the
red sequence, both at z~0.03 and at z~0.8. Similarly, 65-70% of the galaxies
have n>2.5. The fraction of E+S0 galaxies is 43+/-3%$ at z~0.03 and 48+/-7% at
z~0.8, i.e., it has not changed significantly since z~0.8. When combined with
recent results for cluster galaxies in the same redshift range, we find that
the morphology-density relation for galaxies more massive than 0.5M* has
remained constant since at least z~0.8. This implies that galaxies evolve in
mass, morphology and density such that the morphology-density relation does not
change. In particular, the decline of star formation activity and the
accompanying increase in the stellar mass density of red galaxies since z~1
must happen without large changes in the early-type galaxy fraction in a given
environment.Comment: 16 pages, 13 figures, 2 tables. Updated to match journal version.
Will appear in ApJ (vol. 670, p. 206
Botanicals as part of an integral value-added pork production system
Selected herbs are known to naturally possess antibacterial and other characteristics that could be useful in animal protein production. Inclusion of these herbs in animal feeds as alternative growth promotion and efficiency stimulants may be able to address some of the current concerns about the possibility of significant antibiotic-resistant bacteria development that stems from drugs currently used at subtherapeutic levels in animal production. Several herbs were tested for their ability to aid animal growth rates and feed efficiency without giving rise to antibiotic-resistant microbes
A Rest-frame Optical View on z~4 Galaxies I: Color and Age Distributions from Deep IRAC Photometry of the IUDF10 and GOODS Surveys
We present a study of rest-frame UV-to-optical color distributions for z~4
galaxies based on the combination of deep HST/ACS+WFC3/IR data with
Spitzer/IRAC imaging. In particular, we use new, ultra-deep data from the IRAC
Ultradeep Field program (IUDF10). Our sample contains a total of ~2600 galaxies
selected as B-dropout Lyman Break Galaxies (LBGs) in the HUDF and one of its
deep parallel fields, the HUDF09-2, as well as GOODS-North and South. This
sample is used to investigate the UV continuum slopes beta and Balmer break
colors (J_125-[4.5]) as a function of rest-frame optical luminosity. The [4.5]
filter is chosen to avoid potential contamination by strong rest-frame optical
emission lines. We find that galaxies at M_z<-21.5 (roughly corresponding to
L*[z~4]) are significantly redder than their lower luminosity counterparts. The
UV continuum slopes and the J_125-[4.5] colors are well correlated. The most
simple explanation for this correlation is that the dust reddening at these
redshifts is better described by an SMC-like extinction curve, rather than the
typically assumed Calzetti reddening. After correcting for dust, we find that
the galaxy population shows mean stellar population ages in the range 10^8.5 to
10^9 yr, with a dispersion of ~0.5 dex, and only weak trends as a function of
luminosity. In contrast to some results from the literature, we find that only
a small fraction of galaxies shows Balmer break colors which are consistent
with extremely young ages, younger than 100 Myr. Under the assumption of smooth
star-formation histories, this fraction is only 12-19% for galaxies at
M_z<-19.75. Our results are consistent with a gradual build-up of stars and
dust in galaxies at z>4, with only a small fraction of stars being formed in
short, intense bursts of star-formation.Comment: 11 pages, 10 figures; submitted to Ap
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