328 research outputs found
Thomas F. Hargis Letter, 1901
A letter from Thomas F. Hargis to Frank C. Button regarding the laying of a cornerstone at the Morehead Normal School on November 12, 1901
Assessment of a Nutritional Rehabilitation Model in Two Modern Broilers and Their Jungle Fowl Ancestor
Inclusion of rye in poultry diets induces a nutritional deficit that leads to increased bacterial translocation, intestinal viscosity, and decreased bone mineralization. However, the effect of diet on developmental stage or genetic strain is unclear. Therefore, the objective of this chapter is to evaluate the effects of a well-established rye model diet during either the early or the late phase of development on performance, bone mineralization, and morphometric analysis. Furthermore, intestinal integrity evaluated by liver bacterial translocation, leakage of FITC-d, and gene expression of tight junctions across three diverse genetic backgrounds Modern 2015 (Cobb 500) broiler chicken, 1995 Cobb broiler chicken, and the Giant Jungle Fowl are also discussed
Some effects of high-frequency x-rays on the oyster drill Urosalpinx cinerea
Scientists of ·the.Department of Agriculture (Bushland et al. 1955) recently announced the successful eradication of the screw-worm, Callitroga hominivorax, from the Dutch Island of Curacao. This was accomplished by releasing x-ray steralized males, which competed successfully with normal indigenous males for the females. After such matings the monogamous females deposited only sterile egg masses. Although several releases, Were necessary, eventually no fertile eggs Were detected at any of the.numerous observation points. Subsequent checks failed to reveal any live flies.
Because existing information concerning ecology and reproduction of drills appeared favorable, our group was encouraged to investigate this technique as a possible control method for oyster drills. The present paper is a report; of a· series of experiments which were designed to determine the lethal dose
Vertical pairing of identical particles suspended in the plasma sheath
It is shown experimentally that vertical pairing of two identical
microspheres suspended in the sheath of a radio-frequency (rf) discharge at low
gas pressures (a few Pa), appears at a well defined instability threshold of
the rf power. The transition is reversible, but with significant hysteresis on
the second stage. A simple model, which uses measured microsphere resonance
frequencies and takes into account besides Coulomb interaction between
negatively charged microspheres also their interaction with positive ion wake
charges, seems to explain the instability threshold quite well.Comment: 4 pages, 6 figures. to appear in Phys. Rev. Lett. 86, May 14th (2001
Why is the mass function of NGC 6218 flat?
We have used the FORS-1 camera on the VLT to study the main sequence (MS) of
the globular cluster NGC 6218 in the V and R bands. The observations cover an
area of 3.4 x 3.4 around the cluster centre and probe the stellar population
out to the cluster's half-mass radius (r_h ~ 2.2). The colour-magnitude diagram
(CMD) that we derive in this way reveals a narrow and well defined MS extending
down to the 5 sigma detection limit at V~25, or about 6 magnitudes below the
turn-off, corresponding to stars of ~ 0.25 Msolar. The luminosity function (LF)
obtained with these data shows a marked radial gradient, in that the ratio of
lower- and higher-mass stars increases monotonically with radius. The mass
function (MF) measured at the half-mass radius, and as such representative of
the clusters global properties, is surprisingly flat. Over the range 0.4 - 0.8
Msolar, the number of stars per unit mass follows a power-law distribution of
the type dN/dm \propto m^{0}, where, for comparison, Salpeter's IMF would be
dN/dm \propto m^{-2.35}. We expect that such a flat MF does not represent the
cluster's IMF but is the result of severe tidal stripping of the stars from the
cluster due to its interaction with the Galaxy's gravitational field. Our
results cannot be reconciled with the predictions of recent theoretical models
that imply a relatively insignificant loss of stars from NGC 6218 as measured
by its expected very long time to disruption. They are more consistent with the
orbital parameters based on the Hipparcos reference system that imply a much
higher degree of interaction of this cluster with the Galaxy than assumed by
those models. Our results indicate that, if the orbit of a cluster is known,
the slope of its MF could be useful in discriminating between the various
models of the Galactic potential.Comment: 11 pages, 7 figures, accepted for publication in Astronomy and
Astrophysic
Na-O Anticorrelation and HB. IV. Detection of He-rich and He-poor stellar populations in the globular cluster NGC 6218
We used the multifiber spectrograph FLAMES on the ESO Very Large Telescope
UT2 to derive atmospheric parameters, metallicities and abundances of O and Na
for 79 red giant stars in the Galactic globular cluster NGC 6218 (M 12). We
analyzed stars in the magnitude range from about 1 mag below the bump to the
tip of the Red Giant Branch. The average metallicity we derive is
[Fe/H]=-1.31+/-0.004+/-0.028 dex (random and systematic errors, respectively),
with a very small star-to-star scatter (rms=0.033 dex), from moderately
high-resolution Giraffe spectra. This is the first extensive spectroscopic
abundance analysis in this cluster. Our results indicate that NGC 6218 is very
homogeneous as far as heavy elements are concerned. On the other hand, light
elements involved in the well known proton-capture reactions of H-burning at
high temperature, such as O and Na, show large variations, anticorrelated with
each other, at all luminosities along the red giant branch. The conclusion is
that the Na-O anticorrelation must be established in early times at the cluster
formation. We interpret the variation of Na found near the RGB-bump as the
effect of two distinct populations having different bump luminosities, as
predicted for different He content. To our knowledge, NGC 6218 is the first GC
where such a signature has been spectroscopically detected, when combined with
consistent and homogeneous data obtained for NGC 6752 to gain in statistical
significance.Comment: 15 pages, 10 figures; fig.5 degraded in resolution; tables 2,3,5
available at CDS. Accepted for publication on A&
Absolute properties of the low-mass eclipsing binary CM Draconis
Spectroscopic and eclipsing binary systems offer the best means for
determining accurate physical properties of stars, including their masses and
radii. The data available for low-mass stars have yielded firm evidence that
stellar structure models predict smaller radii and higher effective
temperatures than observed, but the number of systems with detailed analyses is
still small. In this paper we present a complete reanalysis of one of such
eclipsing systems, CM Dra, composed of two dM4.5 stars. New and existing light
curves as well as a radial velocity curve are modeled to measure the physical
properties of both components. The masses and radii determined for the
components of CM Dra are M1=0.2310+/-0.0009 Msun, M2=0.2141+/-0.0010 Msun,
R1=0.2534+/-0.0019 Rsun, and R2=0.2396+/-0.0015 Rsun. With relative
uncertainties well below the 1% level, these values constitute the most
accurate properties to date for fully convective stars. This makes CM Dra a
valuable benchmark for testing theoretical models. In comparing our
measurements with theory, we confirm the discrepancies reported previously for
other low-mass eclipsing binaries. These discrepancies seem likely to be due to
the effects of magnetic activity. We find that the orbit of this system is
slightly eccentric, and we have made use of eclipse timings spanning three
decades to infer the apsidal motion and other related properties.Comment: 19 pages, 9 figures. Accepted for publication in Ap
The Luminosity Function and Color-Magnitude Diagram of the Globular Cluster M12
In this paper we present the V and I luminosity functions and color-magnitude
diagrams derived from wide-field (23 arcmin by 23 arcmin) BVI photometry of the
intermediate metallicity ([Fe/H]=-1.3) Galactic globular cluster M12. Using
observed values (and ranges of values) for the cluster metallicity, reddening,
distance modulus, and age we compare these data to recent alpha-enhanced
stellar evolution models for low mass metal-poor stars. We describe several
methods of making comparisons between theoretical and observed luminosity
functions in order to isolate the evolutionary timescale information the
luminosity functions contain. We find no significant evidence of excesses of
stars on the red giant branch, although the morphology of the subgiant branch
in the observed luminosity function does not match theoretical predictions in a
satisfactory way. Current uncertainties in Teff-color transformations (and
possibly also in other physics inputs to the models) make more detailed
conclusions about the subgiant branch morphology impossible. Given the recent
constraints on cluster ages from the WMAP experiment (Spergel et al. 2003), we
find that good fitting models that do not include He diffusion (both
color-magnitude diagrams and luminosity functions) are too old (by
approximately 1-2 Gyr) to adequately represent the cluster luminosity function.
The inclusion of helium diffusion in the models provides an age reduction
(compared to non-diffusive models) that is consistent with the age of the
universe being 13.7+/-0.2 Gyr (Bennett et al. 2003).Comment: 63 pages, 29 figures, accepted for ApJ. Quality of images are
degraded; please e-mail lead author for high-quality PS/PDF preprin
Transition probabilities of 30 Pb II lines of spectrum obtained by emission of a laser-produced plasma
Transition probabilities have been determined for 30 lines of Pb II by measuring the intensities of the emission lines of a laser-produced plasma (LPP) of Pb in an atmosphere of Ar. The plasma has been seen to contain local thermodynamic equilibrium (LTE) and homogeneity; the plasma studied has a temperature of 11 500 K and an electron density of 1016 cm−3. The experimental results obtained during this study have been compared with the experimental and theoretical values given by other authors
Identification of Serum Biomarkers for Intestinal Integrity in a Broiler Chicken Malabsorption Model
Intestinal health is essential for feed efficiency and growth in animal agriculture and is dependent on barrier function, inflammation and dysbiosis. Our laboratory has published a nutritional model to induce gut inflammation using rye as a source of energy in poultry. More recently, we have used this model as an assessment of a nutritional rehabilitation model for better understanding of childhood undernutrition. The objective of this brief research report was to use a well-establish malabsorption model in broiler chickens using corn and rye as an energy source to identify several intestinal health biomarkers in the serum. To screen for inflammatory biomarkers, seven commercially available tests were used including Griess, superoxide dismutase, thiobarbituric acid reactive substances, Total antioxidant capacity, extracellular-signal-regulated kinase, Citrulline, and Interferon-ɤ; total IgA from cloacal swab was also measured. In the present study, chickens fed rye had a significant (P < 0.05) reduction in body weight and body weight gain at 10 day when compared with chickens that received the corn diet. In the second phase of the experiment, chickens that remain with the corn diet had significant differences in body weight and body weight gain. No significant differences were observed for any of the four antioxidant biomarkers evaluated in the sera (P > 0.05). However, significant differences were observed in serum citrulline and IFN-ɤ, as well as in cloacal IgA, in broiler chickens fed with rye, suggesting their potential use as biomarkers to study intestinal inflammation
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