Hydrous magnesium silicate phase D plays a key role in the transport of water from the upper to the lower mantle via subducted slabs. Here we report pressure dependence hyperfine and lattice parameters of FeAl-bearing phase D up to megabar pressures using synchrotron nuclear forward scattering and X-ray diffraction in a diamond anvil cell at room temperature. FeAl-bearing phase D undergoes a two-stage high-spin to low-spin transition of iron for Fe2+ at 37-41GPa and for Fe3+ at 64-68GPa. These transitions are accompanied by an increase in density and a significant softening in the bulk modulus and bulk velocity at their respective pressure range. The occurrence of the dense low-spin FeAl-bearing phase D with relatively high velocity anisotropies in deep-subducted slabs can potentially contribute to small-scale seismic heterogeneities in the middle-lower mantle beneath the circum-Pacific area.

In this study, we performed synchrotron X-ray diffraction (XRD) and Mossbauer spectroscopy (SMS) measurements on two single-crystal bridgmanite samples [Mg0.94Fe0.042+Fe0.023+Al0.01Si0.99O3(Bm6) and Mg0.89Fe0.0242+Fe0.0963+Al0.11Si0.89O3 (Al-Bm11)] to investigate the combined effect of Fe and Al on the hyperfine parameters, lattice parameters, and equation of state (EoS) of bridgmanite up to 130 GPa. Our SMS results show that Fe2+ and Fe3+ in Bm6 and Al-Bml l are predominantly located in the large pseudo-dodecahedral sites (A-site) at lower-mantle pressures. The observed drastic increase in the hyperfine quadrupole splitting (QS) between 13 and 32 GPa can be associated with an enhanced local distortion of the A-site Fe2+ in Bm6. In contrast to Bm6, the enhanced lattice distortion and the presence of extremely high QS values of Fe2+ are not observed in Al-Bml l at high pressures. Our results here support the notion that the occurrence of the extremely high QS component of approximately 4 mm/s in bridgmanite is due to the lattice distortion in the high-spin (HS) A-site Fe2+, instead of the occurrence of the intermediate-spin state. Both A-site Fe2+ and Fe3+ in Bm6 and Al-Bml l remain in the HS state at lower-mantle pressures. Together with XRD results, we present the first experimental evidence that the enhanced lattice distortion of A-site Fe2+ does not cause any detectable variation in the EoS parameters, but is associated with anomalous variations in the bond length, tilting angle, and shear strain in the octahedra of Bm6. Analysis of the obtained EoS parameters of bridgmanite at lower-mantle pressures indicates that the substitution of Fe in bridgmanite will cause an enhanced density and a reduced bulk sound velocity (V-Phi), whereas the Al and Fe substitution has a reduced effect on density and a negligible effect on V-Phi. These experimental results provide new insight into the correlation between lattice, hyperfine, and EoS parameters of bridgmanite in the Earth's lower mantle.

We investigated Fe-free and Fe-bearing CF phases using nuclear forward scattering and X-ray diffraction coupled with diamond anvil cells up to 80GPa at room temperature. Octahedral Fe3+ ions in the Fe-bearing CF phase undergo a high-spin to low-spin transition at 25-35GPa, accompanied by a volume reduction of similar to 2.0% and a softening of bulk sound velocity up to 17.6%. Based on the results of this study and our previous studies, both the NAL and CF phases, which account for 10-30 vol % of subducted MORB in the lower mantle, are predicted to undergo a spin transition of octahedral Fe3+ at lower mantle pressures. Spin transitions in these two aluminous phases result in an increase of density of 0.24% and a pronounced softening of bulk sound velocity up to 2.3% for subducted MORB at 25-60GPa and 300K. The anomalous elasticity region expands and moves to 30-75GPa at 1200K and the maximum of the V reduction decreases to similar to 1.8%. This anomalous elastic behavior of Fe-bearing aluminous phases across spin transition zones may be relevant in understanding the observed seismic signatures in the lower mantle.

Femtosecond resolution electron scattering techniques are applied to resolve the first atomic-scale steps following absorption of a photon in the prototypical hybrid perovskite methylammonium lead iodide. Following above-gap photoexcitation, we directly resolve the transfer of energy from hot carriers to the lattice by recording changes in the mean square atomic displacements on 10-ps time scales. Measurements of the time-dependent pair distribution function show an unexpected broadening of the iodine-iodine correlation function while preserving the Pb-I distance. This indicates the formation of a rotationally disordered halide octahedral structure developing on picosecond time scales. This work shows the important role of light-induced structural deformations within the inorganic sublattice in elucidating the unique optoelectronic functionality exhibited by hybrid perovskites and provides new understanding of hot carrier-lattice interactions, which fundamentally determine solar cell efficiencies.

We present the final results from our survey of luminous z similar to 5.5 quasars. This is the first systematic quasar survey focusing on quasars at z similar to 5.5, during the post-reionization epoch. It has been challenging to select quasars at 5.3 < z < 5.7 using conventional color selections, due to their similar optical colors to those of late-type stars, especially M dwarfs. We developed a new selection technique for z similar to 5.5 quasars based on optical, near-infrared (IR), and mid-IR photometry, using data from the Sloan Digital Sky Survey (SDSS), PanSTARR1 (PS1), the UKIRT Infrared Deep Sky Surveys-Large Area Survey, the UKIRT Hemisphere Survey, the VISTA Hemisphere Survey, and the Wide Field Infrared Survey Explorer, covering similar to 11,000 deg(2) of high galactic latitude sky. In this paper, we present the discovery of 15 new quasars at 5.22 >= z >= 5.78. Together with results from Yang et al., our survey provides a complete, flux-limited sample of 31 quasars at 5.3 >= z >= 5.7. We measure the quasar spatial density at z similar to 5.5 and M1450 < -26.2. Our result is consistent with the rapid decline of the quasar spatial density from z = 5 to 6, with k = -0.66 +/- 0.05 (rho(z) alpha 10(kz)). In addition, we present a new survey using optical colors only from the full PS1 area for luminous quasars at z = 5.0-5.5, which is beyond the SDSS footprint, and report the preliminary results from this survey, including 51 new quasars discovered at 4.61 <= z <= 5.71.

Gene expression data from isolated endodermal cells after roots were treated with 140 mM NaCl for 20 hour Data quality was examined using the signal distribution of Affymetrix built-in controls (Spike-in and hybridization controls) using Expression Console software (Affymetrix) and AffyQCReport. GCRMA in R/Bioconductor was used for data normalization.

Gene expression data from isolated stele cells after roots were treated with 140 mM NaCl for 8 hour Data quality was examined using the signal distribution of Affymetrix built-in controls (Spike-in and hybridization controls) using Expression Console software (Affymetrix) and AffyQCReport. GCRMA in R/Bioconductor was used for data normalization.

Gene expression data from isolated endodermal cells after roots were treated with 140 mM NaCl for 32 hour Data quality was examined using the signal distribution of Affymetrix built-in controls (Spike-in and hybridization controls) using Expression Console software (Affymetrix) and AffyQCReport. GCRMA in R/Bioconductor was used for data normalization.

Gene expression data from isolated endodermal cells after roots were treated with 140 mM NaCl for 48 hour Data quality was examined using the signal distribution of Affymetrix built-in controls (Spike-in and hybridization controls) using Expression Console software (Affymetrix) and AffyQCReport. GCRMA in R/Bioconductor was used for data normalization.

Gene expression data from isolated stele cells Data quality was examined using the signal distribution of Affymetrix built-in controls (Spike-in and hybridization controls) using Expression Console software (Affymetrix) and AffyQCReport. GCRMA in R/Bioconductor was used for data normalization.