368 research outputs found
An Evaluation of Hybrid Traits, Yield, and Major QTL Effect on Heterosis in Hybrid Soft Red Winter Wheat
Wheat (Triticum aestivum L.) is a self-pollinating species that is most often bred as a recombinant inbred line. When two inbred individuals are crossed, they produce progeny which experience heterosis; heterosis is the increased robustness experienced due to the reintroduction of heterozygosity. Hybrid wheat may be produced through the use of chemical hybridization agents, yet the structure of wheat flowers decreases the efficiency of outcrossing. The objectives of this study were to: assess the amount of heterosis experienced by a population of hybrid wheat and observe the effect of major gene loci on yield and yield components, phenotype anthers extruded using image analysis, and find marker-trait associations for anther extrusion. In 2018, 22 soft red winter wheat (SRWW) hybrid lines were planted in two replications of a randomized complete block design (RCBD) in Arkansas, Georgia, and Louisiana. The 22 hybrids were evaluated for yield components and two heterotic indexes: midparent heterosis (MPH) and better-parent heterosis (BPH). Significant (p\u3c0.05) MPH and BPH was observed in all locations for multiple traits. Significant effects (p\u3c0.05) on yield were detected for Vrn-A1, Vrn-B1, Ppd-A1, and Ppd-D1 loci allelic combinations. In 2019, 594 SRWW lines were planted in two replications of a RCBD in Arkansas and phenotyped using image analysis for area of anthers and area per spike. A significant regression (R^2=0.8007,p\u3c0.0001) was found between the area of anthers extruded (AOAE) and the number of anthers extruded (NOAE). Variety was found to play a significant role (F_0.05,530,583=1.36,p=0.0002) in the area per spike (APS) experienced. The presence or absence of awns was also found to play a significant role (F_0.05,1,583=1074.67,p\u3c0.0001) in the area per spike experienced. Several significant (p\u3c0.0001) marker-trait associations were found for NOAE, AOAE, and APS. This information will be used to make selections for male lines in hybrid crossing blocks
A Third Exoplanetary System with Misaligned Orbital and Stellar Spin Axes
We present evidence that the WASP-14 exoplanetary system has misaligned
orbital and stellar-rotational axes, with an angle lambda = 33.1 +/- 7.4 deg
between their sky projections. The evidence is based on spectroscopic
observations of the Rossiter-McLaughlin effect as well as new photometric
observations. WASP-14 is now the third system known to have a significant
spin-orbit misalignment, and all three systems have "super-Jupiter" planets
(M_P > 3 Mjup) and eccentric orbits. This finding suggests that the migration
and subsequent orbital evolution of massive, eccentric exoplanets is somehow
different from that of less massive close-in Jupiters, the majority of which
have well-aligned orbits.Comment: 8 pages, 5 figures, 3 tables, PASP accepte
The Transit Ingress and the Tilted Orbit of the Extraordinarily Eccentric Exoplanet HD 80606b
We present the results of a transcontinental campaign to observe the 2009
June 5 transit of the exoplanet HD 80606b. We report the first detection of the
transit ingress, revealing the transit duration to be 11.64 +/- 0.25 hr and
allowing more robust determinations of the system parameters. Keck spectra
obtained at midtransit exhibit an anomalous blueshift, giving definitive
evidence that the stellar spin axis and planetary orbital axis are misaligned.
The Keck data show that the projected spin-orbit angle is between 32-87 deg
with 68.3% confidence and between 14-142 deg with 99.73% confidence. Thus the
orbit of this planet is not only highly eccentric (e=0.93), but is also tilted
away from the equatorial plane of its parent star. A large tilt had been
predicted, based on the idea that the planet's eccentric orbit was caused by
the Kozai mechanism. Independently of the theory, it is noteworthy that all 3
exoplanetary systems with known spin-orbit misalignments have massive planets
on eccentric orbits, suggesting that those systems migrate differently than
lower-mass planets on circular orbits.Comment: ApJ, in press [13 pg
Long-Term Transit Timing Monitoring and Refined Light Curve Parameters of HAT-P-13b
We present 10 new transit light curves of the transiting hot Jupiter
HAT-P-13b, obtained during two observational seasons by three different
telescopes. When combined with 12 previously published light curves, we have a
sample consisting of 22 transit light curves, spanning 1,041 days across four
observational seasons. We use this sample to examine the recently observed
large-amplitude transit timing variations (P\'al et al. 2011), and give refined
system parameters. We find that the transit times are consistent with a linear
ephemeris, with the exception of a single transit time, from UT 2009 Nov 5, for
which the measured mid transit time significantly deviates from our linear
ephemeris. The nature of this deviation is not clear, and the rest of the data
does not show any significant transit timing variation.Comment: accepted to AJ on 2011-07-1
TERMS Photometry of Known Transiting Exoplanets
The Transit Ephemeris Refinement and Monitoring Survey (TERMS) conducts
radial velocity and photometric monitoring of known exoplanets in order to
refine planetary orbits and predictions of possible transit times. This effort
is primarily directed towards planets not known to transit, but a small sample
of our targets consist of known transiting systems. Here we present precision
photometry for 6 WASP planets acquired during their transit windows. We perform
a Markov Chain Monte Carlo (MCMC) analysis for each planet and combine these
data with previous measurements to redetermine the period and ephemerides for
these planets. These observations provide recent mid-transit times which are
useful for scheduling future observations. Our results improve the ephemerides
of WASP-4b, WASP-5b and WASP-6b and reduce the uncertainties on the mid-transit
time for WASP-29b. We also confirm the orbital, stellar and planetary
parameters of all 6 systems.Comment: 12 pages; 6 figures; 9 tables; accepted for publication in AJ; two
references updated and minor improvements made to match the version to be
publishe
NLTT 41135: a field M-dwarf + brown dwarf eclipsing binary in a triple system, discovered by the MEarth observatory
We report the discovery of an eclipsing companion to NLTT 41135, a nearby M5
dwarf that was already known to have a wider, slightly more massive common
proper motion companion, NLTT 41136, at 2.4 arcsec separation. Analysis of
combined-light and radial velocity curves of the system indicates that NLTT
41135B is a 31-34 +/- 3 MJup brown dwarf (where the range depends on the
unknown metallicity of the host star) on a circular orbit. The visual M-dwarf
pair appears to be physically bound, so the system forms a hierarchical triple,
with masses approximately in the ratio 8:6:1. The eclipses are grazing,
preventing an unambiguous measurement of the secondary radius, but follow-up
observations of the secondary eclipse (e.g. with the James Webb Space
Telescope) could permit measurements of the surface brightness ratio between
the two objects, and thus place constraints on models of brown dwarfs.Comment: 15 pages, 6 figures, 10 tables, emulateapj format. Accepted for
publication in Ap
LHS6343C: A Transiting Field Brown Dwarf Discovered by the Kepler Mission
We report the discovery of a brown dwarf that transits one member of the M+M
binary system LHS6343AB every 12.71 days. The transits were discovered using
photometric data from the Kelper public data release. The LHS6343 stellar
system was previously identified as a single high-proper-motion M dwarf. We use
high-contrast imaging to resolve the system into two low-mass stars with masses
0.45 Msun and 0.36 Msun, respectively, and a projected separation of 55 arcsec.
High-resolution spectroscopy shows that the more massive component undergoes
Doppler variations consistent with Keplerian motion, with a period equal to the
transit period and an amplitude consistent with a companion mass of M_C = 62.8
+/- 2.3 Mjup. Based on an analysis of the Kepler light curve we estimate the
radius of the companion to be R_C = 0.832 +/- 0.021 Rjup, which is consistent
with theoretical predictions of the radius of a > 1 Gyr brown dwarf.Comment: Our previous analysis neglected the dependence of the scaled
semimajor axis, a/R, on the transit depth. By not correcting a/R for the
third-light contamination, we overestimated the mass of Star A, which led to
an overestimate the mass and radius of the LHS6343
Characterizing the Cool KOIs II. The M Dwarf KOI-254 and its Hot Jupiter
We report the confirmation and characterization of a transiting gas giant
planet orbiting the M dwarf KOI-254 every 2.455239 days, which was originally
discovered by the Kepler mission. We use radial velocity measurements, adaptive
optics imaging and near infrared spectroscopy to confirm the planetary nature
of the transit events. KOI-254b is the first hot Jupiter discovered around an
M-type dwarf star. We also present a new model-independent method of using
broadband photometry to estimate the mass and metallicity of an M dwarf without
relying on a direct distance measurement. Included in this methodology is a new
photometric metallicity calibration based on J-K colors. We use this technique
to measure the physical properties of KOI-254 and its planet. We measure a
planet mass of Mp = 0.505 Mjup, radius Rp = 0.96 Rjup and semimajor axis a =
0.03 AU, based on our measured stellar mass Mstar = 0.59 Msun and radius Rstar
= 0.55 Rsun. We also find that the host star is metal-rich, which is consistent
with the sample of M-type stars known to harbor giant planets.Comment: AJ accepted (in press
Concert recording 2016-02-04
[Track 01]. Der Schmetterling / Franz Schubert -- [Track 02]. Moonshine lullaby from Annie get your gun / Irving Berlin -- [Track 03]. Voi, che sapete from Le Nozze di Figaro / Wolfgang Amadeus Mozart -- [Track 04]. Barcarolle from Les contes d\u27Hoffman / Jacques Offenbach -- [Track 05]. A maiden fair to see from H.M.S. Pinafore / Gilbert and Sullivan -- [Track 06]. Im wunderschönen Monat Mai from Dichterliebe / Robert Schumann -- [Track 07]. L\u27heure exquise / Reynaldo Hahn -- [Track 08]. And this is my beloved from Kismet / Wright ; Forest -- [Track 09]. Wenn mein Schatz Hochzeit macht from Lieder eines fahrenden Gesellen / Gustav Mahler -- [Track 10]. Va! Laisse couler mes larmes from Werther / Jules Massenet -- [Track 11]. Give me Jesus / traditional ; arranged by Moses Hogan -- [Track 12]. Il lacerato spirito from Simon Boccanegra / Giuseppe Verdi -- [Track 13]. Giunse alfin il momento...Deh viene, non tardar from Le nozze di Figaro / Wolfgang Amadeus Mozart -- [Track 14]. St. Ita\u27s vision from Hermit songs / Samuel Barber -- [Track 15]. Adele\u27s audition aria from Die Fledermaus / Johann Strauss -- [Track 16]. A part of that from The last five years / Jason Robert Brown -- [Track 17]. Two for the road / Henry Mancini -- [Track 18]. Nel cor piu non mi sento / Giovanni Paisiello -- [Track 19]. Love\u27s minstrels from The house of life / Ralph Vaughan-Williams -- [Track 20]. Der stürmische Morgen / Franz Schubert -- [Track 21]. Die Lotosblume / Robert Schumann -- [Track 22]. Nothing from A chorus line / Hammlisch ; Kleban -- [Track 23]. Spiel auf deiner Geige / Robert Stolz
Affectus Hispaniae en la historiografía del Alto Imperio
This paper analyses texts written by Greek and Latin High Empire historians dealing with Hispania. Some of the authors have a very positive view (Florus, Iustinus, Appian) while others are clearly negative (Veleius Paterculus, Valerius Maximus) though most of them show little interest, indifference or variety of opinions. When there is interest in the region or praise, it is because the author comes from Hispania or he is trying to please an emperor born in Hispania, but it could also be due to a universal conception of history revealing a critical attitude towards Roman imperialism, as in Appian. The praise found in Iustinus’s epitome should be attributed to the author of the epitome rather than to Pompeius Trogus. This can be taken as evidence for situating Iustinus’s life and work in the 2nd century A.D. Loathing of Hispania seems to have its origins in conservative, ‘optimate’ nationalist circles, who perceive the province as the ‘popular’ region that acclaimed and welcomed ‘seditious’ individuals such as Tiberius Gracchus and Sertorius.Se estudian en este trabajo los textos de historiadores del Alto Imperio, latinos y griegos, que tratan sobre Hispania. En algunos autores encontramos una visión muy positiva (Floro, Justino, Apiano) y en otros claramente negativa (Veleyo Patérculo, Valerio Máximo), aunque en la mayoría de los casos hay escasa atención, indiferencia o diversidad de opiniones. El interés por la región y los elogios pueden estar motivados por el origen hispánico del autor o su voluntad de agradar a algún emperador oriundo de Hispania, pero también por una concepción universal de la historia que denota en ocasiones una posición crítica con el imperialismo romano, como es el caso de Apiano. La alabanza que hallamos en el epítome de Justino creemos que debe atribuirse más al epitomador que a Pompeyo Trogo, lo que apoyaría una datación temprana de la vida y la obra de Justino (s. II d.C.). La aversión hacia Hispania parece haber surgido en medios conservadores, “optimates” nacionalistas, que ven la provincia como el territorio “popular”, que encumbró y acogió a “sediciosos” como Tiberio Graco y Sertorio
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