1,820 research outputs found
Genome-wide Association And High-resolution Phenotyping Link Oryza Sativa Panicle Traits To Numerous Trait-specific Qtl Clusters
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Rice panicle architecture is a key target of selection when breeding for yield and grain quality. However, panicle phenotypes are difficult to measure and susceptible to confounding during genetic mapping due to correlation with flowering and subpopulation structure. Here we quantify 49 panicle phenotypes in 242 tropical rice accessions with the imaging platform PANorama. Using flowering as a covariate, we conduct a genome-wide association study (GWAS), detect numerous subpopulation-specific associations, and dissect multi-trait peaks using panicle phenotype covariates. Ten candidate genes in pathways known to regulate plant architecture fall under GWAS peaks, half of which overlap with quantitative trait loci identified in an experimental population. This is the first study to assess inflorescence phenotypes of field-grown material using a high-resolution phenotyping platform. Herein, we establish a panicle morphocline for domesticated rice, propose a genetic model underlying complex panicle traits, and demonstrate subtle links between panicle size and yield performance.7Bill and Melinda Gates FoundationFAPESP [2011/03110-6]NSF Plant Genome Research Program [1026555]NSF Graduate Research Fellowship Program (NSF-GRFP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP
Electrical Detection of Spin Accumulation at a Ferromagnet-Semiconductor Interface
We show that the accumulation of spin-polarized electrons at a forward-biased
Schottky tunnel barrier between Fe and n-GaAs can be detected electrically. The
spin accumulation leads to an additional voltage drop across the barrier that
is suppressed by a small transverse magnetic field, which depolarizes the spins
in the semiconductor. The dependence of the electrical accumulation signal on
magnetic field, bias current, and temperature is in good agreement with the
predictions of a drift-diffusion model for spin-polarized transport.Comment: Submitted to Phys. Rev. Let
An Aerothermoelastic Analysis Framework Enhanced by Model Order Reduction With Applications
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143034/1/6.2017-1601.pd
A STUDY OF EXTRACELLULAR SPACE IN CENTRAL NERVOUS TISSUE BY FREEZE-SUBSTITUTION
It was attempted to preserve the water distribution in central nervous tissue by rapid freezing followed by substitution fixation at low temperature. The vermis of the cerebellum of white mice was frozen by bringing it into contact with a polished silver mirror maintained at a temperature of about -207°C. The tissue was subjected to substitution fixation in acetone containing 2 per cent OsO4 at -85°C for 2 days, and then prepared for electron microscopy by embedding in Maraglas, sectioning, and staining with lead citrate or uranyl acetate and lead. Cerebellum frozen within 30 seconds of circulatory arrest was compared with cerebellum frozen after 8 minutes' asphyxiation. From impedance measurements under these conditions, it could be expected that in the former tissue the electrolyte and water distribution is similar to that in the normal, oxygenated cerebellum, whereas in the asphyxiated tissue a transport of water and electrolytes into the intracellular compartment has taken place. Electron micrographs of tissue frozen shortly after circulatory arrest revealed the presence of an appreciable extracellular space between the axons of granular layer cells. Between glia, dendrites, and presynaptic endings the usual narrow clefts and even tight junctions were found. Also the synaptic cleft was of the usual width (250 to 300 A). In asphyxiated tissue, the extracellular space between the axons is either completely obliterated (tight junctions) or reduced to narrow clefts between apposing cell surfaces
Spin injection from perpendicular magnetized ferromagnetic -MnGa into (Al,Ga)As heterostructures
Electrical spin injection from ferromagnetic -MnGa into an (Al,Ga)As
p-i-n light emitting diode (LED) is demonstrated. The -MnGa layers show
strong perpendicular magnetocrystalline anisotropy, enabling detection of spin
injection at remanence without an applied magnetic field. The bias and
temperature dependence of the spin injection are found to be qualitatively
similar to Fe-based spin LED devices. A Hanle effect is observed and
demonstrates complete depolarization of spins in the semiconductor in a
transverse magnetic field.Comment: 4 pages, 3 figure
Optical and electrical spin injection and spin transport in hybrid Fe/GaAs devices
We discuss methods for imaging the nonequilibrium spin polarization of
electrons in Fe/GaAs spin transport devices. Both optically- and
electrically-injected spin distributions are studied by scanning
magneto-optical Kerr rotation microscopy. Related methods are used to
demonstrate electrical spin detection of optically-injected spin polarized
currents. Dynamical properties of spin transport are inferred from studies
based on the Hanle effect, and the influence of strain on spin transport data
in these devices is discussed.Comment: 5 pages, 6 figs. ICPS-28 proceedings (July'06, Vienna) for J. Appl.
Phy
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