580 research outputs found
Subsoil Textural Variations on the ClarionWebster Experimental Farm as Related to the Mankato Glacial Deposit
The Clarion-Webster Experimental Farm is an 80-acre experimental farm of Iowa State College located 1 mile south of Kanawha, Iowa (WY2 SWYJ, Sec. 34, T94N, R25W, Hancock County). A detailed soil map was made to determine the uniformity of the soils and the subsoil material. The map was constructed from the results of auger borings, 54 to 60 inches deep, located at the corners of a 50-foot square grid laid out on the tract. Thus, there were more than 1,000 borings made on the 80 acres
A Relocation of Part of the Mankato Drift Boundary in Hand County, South Dakota
Flint (1) has shown the areal distribution of the Cary and Mankato glacial drifts in South Dakota. Studies of the distribution of soils in southern Hand County (2) make possible the refinement of the Mankato drift boundary in that area. Although the area in question is relatively small (approximately 95 square miles) when compared to the distribution of the two drifts in the state, it is a significant part of the county. The criteria used in relocating the boundary are: (1) kinds of soil profiles, (2) presence or absence of loess, (3) melt water channels and outwash, (4) composition of the tills and (5) moraines
Nature of Reduced Carbon in Martian Meteorites
Martian meteorites provide important information on the nature of reduced carbon components present on Mars throughout its history. The first in situ analyses for carbon on the surface of Mars by the Viking landers yielded disappointing results. With the recognition of Martian meteorites on Earth, investigations have shown carbon-bearing phases exist on Mars. Studies have yielded presence of reduced carbon, carbonates and inferred graphitic carbon phases. Samples ranging in age from the first approximately 4 Ga of Mars history [e.g. ALH84001] to nakhlites with a crystallization age of 1.3 Ga [e.g. Nakhla] with aqueous alteration processes occurring 0.5-0.7 Ga after crystallizaton. Shergottites demonstrate formation ages around 165-500 Ma with younger aqueous alterations events. Only a limited number of the Martian meteorites do not show evidence of significance terrestrial alterations. Selected areas within ALH84001, Nakhla, Yamato 000593 and possibly Tissint are suitable for study of their indigenous reduced carbon bearing phases. Nakhla possesses discrete, well-defined carbonaceous phases present within iddingsite alteration zones. Based upon both isotopic measurements and analysis of Nakhla's organic phases the presence of pre-terrestrial organics is now recognized. The reduced carbon-bearing phases appear to have been deposited during preterrestrial aqueous alteration events that produced clays. In addition, the microcrystalline layers of Nakhla's iddingsite have discrete units of salt crystals suggestive of evaporation processes. While we can only speculate on the origin of these unique carbonaceous structures, we note that the significance of such observations is that it may allow us to understand the role of Martian carbon as seen in the Martian meteorites with obvious implications for astrobiology and the pre-biotic evolution of Mars. In any case, our observations strongly suggest that reduced organic carbon exists as micrometer- size, discrete structures on Mars associated with clay and salt minerals. The Mars Science Laboratory s investigators should be aware of reduced organic carbon components within clay-bearing phases
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Examination of Fluconazole-Induced Alopecia in an Animal Model and Human Cohort.
Fluconazole-induced alopecia is a significant problem for patients receiving long-term therapy. We evaluated the hair cycle changes of fluconazole in a rat model and investigated potential molecular mechanisms. Plasma and tissue levels of retinoic acid were not found to be causal. Human patients with alopecia attributed to fluconazole also underwent detailed assessment and in both our murine model and human cohort fluconazole induced telogen effluvium. Future work further examining the mechanism of fluconazole-induced alopecia should be undertaken
Connecting LHC, ILC, and Quintessence
If the cold dark matter consists of weakly interacting massive particles
(WIMPs), anticipated measurements of the WIMP properties at the Large Hadron
Collider (LHC) and the International Linear Collider (ILC) will provide an
unprecedented experimental probe of cosmology at temperatures of order 1 GeV.
It is worth emphasizing that the expected outcome of these tests may or may not
be consistent with the picture of standard cosmology. For example, in
kination-dominated quintessence models of dark energy, the dark matter relic
abundance can be significantly enhanced compared to that obtained from freeze
out in a radiation-dominated universe. Collider measurements then will
simultaneously probe both dark matter and dark energy. In this article, we
investigate the precision to which the LHC and ILC can determine the dark
matter and dark energy parameters under those circumstances. We use an
illustrative set of four benchmark points in minimal supergravity in analogy
with the four LCC benchmark points. The precision achievable together at the
LHC and ILC is sufficient to discover kination-dominated quintessence, under
the assumption that the WIMPs are the only dark matter component. The LHC and
ILC can thus play important roles as alternative probes of both dark matter and
dark energy.Comment: 38 pages, 9 figure
Implications of Dramatic Broad Absorption Line Variability in the Quasar FBQS J1408+3054
We have observed a dramatic change in the spectrum of the formerly heavily
absorbed `overlapping-trough' iron low-ionization broad absorption line
(FeLoBAL) quasar FBQS J1408+3054. Over a time span of between 0.6 to 5
rest-frame years, the Mg II trough outflowing at 12,000 km/s decreased in
equivalent width by a factor of two and the Fe II troughs at the same velocity
disappeared. The most likely explanation for the variability is that a
structure in the BAL outflow moved out of our line of sight to the ultraviolet
continuum emitting region of the quasar's accretion disk. Given the size of
that region, this structure must have a transverse velocity of between 2600
km/s and 22,000 km/s. In the context of a simple outflow model, we show that
this BAL structure is located between approximately 5800 and 46,000
Schwarzschild radii from the black hole. That distance corresponds to 1.7 to 14
pc, 11 to 88 times farther from the black hole than the H-beta broad-line
region. The high velocities and the parsec-scale distance for at least this one
FeLoBAL outflow mean that not all FeLoBAL outflows can be associated with
galaxy-scale outflows in ultraluminous infrared galaxies transitioning to
unobscured quasars. The change of FBQS J1408+3054 from an FeLoBAL to a LoBAL
quasar also means that if (some) FeLoBAL quasars have multiwavelength
properties which distinguish them from HiBAL quasars, then some LoBAL quasars
will share those properties. Finally, we extend previous work on how
multiple-epoch spectroscopy of BAL and non-BAL quasars can be used to constrain
the average lifetime of BAL episodes (currently >60 rest-frame years at 90%
confidence).Comment: Final version to appear in MNRAS: references added and factor of 2
underestimate of accretion disk size corrected, resulting in absorber
constrained to be somewhat closer to the black hole. For an animated gif
showing the spectral evolution of the broad absorption line troughs in this
quasar, see http://www.yorku.ca/phall/film19952009.gi
Quasars and their host galaxies
This review attempts to describe developments in the fields of quasar and
quasar host galaxies in the past five. In this time period, the Sloan and 2dF
quasar surveys have added several tens of thousands of quasars, with Sloan
quasars being found to z>6. Obscured, or partially obscured quasars have begun
to be found in significant numbers. Black hole mass estimates for quasars, and
our confidence in them, have improved significantly, allowing a start on
relating quasar properties such as radio jet power to fundamental parameters of
the quasar such as black hole mass and accretion rate. Quasar host galaxy
studies have allowed us to find and characterize the host galaxies of quasars
to z>2. Despite these developments, many questions remain unresolved, in
particular the origin of the close relationship between black hole mass and
galaxy bulge mass/velocity dispersion seen in local galaxies.Comment: Review article, to appear in Astrophysics Update
Kepler-432: a red giant interacting with one of its two long period giant planets
We report the discovery of Kepler-432b, a giant planet ()
transiting an evolved star with an orbital period of days. Radial velocities (RVs) reveal that
Kepler-432b orbits its parent star with an eccentricity of , which we also measure independently with
asterodensity profiling (AP; ), thereby confirming
the validity of AP on this particular evolved star. The well-determined
planetary properties and unusually large mass also make this planet an
important benchmark for theoretical models of super-Jupiter formation.
Long-term RV monitoring detected the presence of a non-transiting outer planet
(Kepler-432c; days), and adaptive optics imaging revealed a nearby
(0\farcs87), faint companion (Kepler-432B) that is a physically bound M dwarf.
The host star exhibits high signal-to-noise asteroseismic oscillations, which
enable precise measurements of the stellar mass, radius and age. Analysis of
the rotational splitting of the oscillation modes additionally reveals the
stellar spin axis to be nearly edge-on, which suggests that the stellar spin is
likely well-aligned with the orbit of the transiting planet. Despite its long
period, the obliquity of the 52.5-day orbit may have been shaped by star-planet
interaction in a manner similar to hot Jupiter systems, and we present
observational and theoretical evidence to support this scenario. Finally, as a
short-period outlier among giant planets orbiting giant stars, study of
Kepler-432b may help explain the distribution of massive planets orbiting giant
stars interior to 1 AU.Comment: 22 pages, 19 figures, 5 tables. Accepted to ApJ on Jan 24, 2015
(submitted Nov 11, 2014). Updated with minor changes to match published
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