Temperature dependent-electrical resistance of n-type Bi2Te3 was investigated under high pressure. Superconductivity was detected at 4.9 GPa with Tc-onset = 2.8 K. Resistance and T-c suggest that there are two electronic phase transitions below 10 GPa. We conjecture that the bulk insulating phase first changes to semimetal and then to metal. The evolution of the Hall coefficient is qualitatively consistent with the proposed electronic phase transition. The origin of superconductivity and topological properties are also discussed. Published by AIP Publishing.

Long-term ground LAI measurements from the global networks of sites (e.g. FLUXNET) have emerged as a promising data source to validate remotely sensed global LAI product time-series. However, the spatial scale-mismatch issue between site and satellite observations hampers the use of such invaluable ground measurements in validation practice. Here, we propose an approach (Grading and Upscaling of Ground Measurements, GUGM) that integrates a spatial representativeness grading criterion and a spatial upscaling strategy to resolve this scale-mismatch issue and maximize the utility of time-series of site-based LAI measurements. The performance of GUGM was carefully evaluated by comparing this method to both benchmark LAI and other widely used conventional approaches. The uncertainty of three global LAI products (i.e. MODIS, GLASS and GEOV1) was also assessed based on the LAI time-series validation dataset derived from GUGM. Considering all the evaluation results together, this study suggests that the proposed GUGM approach can significantly reduce the uncertainty from spatial scale mismatch and increase the size of the available validation dataset. In particular, the proposed approach outperformed other widely used approaches in these two respects. Furthermore, GUGM was successfully implemented to validate global LAI products in various ways with advantaging frequent time-series validation dataset. The validation results of the global LAI products show that GLASS has the lowest uncertainty, followed by GEOV1 and MODIS for the overall biome types. However, MODIS provides more consistent uncertainties across different years than GLASS and GEOV1. We believe that GUGM enables us to better understand the structure of LAI product uncertainties and their evolution across seasonal or annual contexts. In turn, this method can provide fundamental information for further LAI algorithm improvements and the broad application of LAI product time-series.

The electronic excitation of 3d transition metal oxide depends on the hybridization between orbitals of different ions, and is related to the materials properties. In this work, we systematically study the effect of hydrostatic pressure up to similar to 20 GPa on the crystal structure and electronic structure of Pr0.67Sr0.33MnO3 powder, using Mn K-edge X-ray absorption near edge structure and X-ray diffraction at room temperature. With the increase of pressure, the energy position of non-local screened feature moves towards feature without screening due to the enhanced transition energy; however, the intensity (probability) of non-local screened feature increases with the pressure. Further study suggests that the pressure-induced antiferromagnetic phase, affecting hybridization between neighboring Mn ions with spin sensitivity, increase the probability of non-local charge transfer and corresponding intensity of non-local screened feature. The spin-sensitivity of non-local screening may be a useful parameter for characterization of material properties. (c) 2019 Elsevier B.V. All rights reserved.

A drastically altered chemistry was recently discovered in the Fe-O-H system under deep Earth conditions, involving the formation of iron superoxide (FeO(2)Hx with x = 0 to 1), but the puzzling crystal chemistry of this system at high pressures is largely unknown. Here we present evidence that despite the high O/Fe ratio in FeO(2)Hx, iron remains in the ferrous, spin-paired and non-magnetic state at 60-133 GPa, while the presence of hydrogen has minimal effects on the valence of iron. The reduced iron is accompanied by oxidized oxygen due to oxygen-oxygen interactions. The valence of oxygen is not -2 as in all other major mantle minerals, instead it varies around -1. This result indicates that like iron, oxygen may have multiple valence states in our planet's interior. Our study suggests a possible change in the chemical paradigm of how oxygen, iron, and hydrogen behave under deep Earth conditions.

We present the survey design, implementation, and outlook for COSMOS-Web, a 255 hr treasury program conducted by the James Webb Space Telescope in its first cycle of observations. COSMOS-Web is a contiguous 0.54 deg(2) NIRCam imaging survey in four filters (F115W, F150W, F277W, and F444W) that will reach 5 & sigma; point-source depths ranging & SIM;27.5-28.2 mag. In parallel, we will obtain 0.19 deg(2) of MIRI imaging in one filter (F770W) reaching 5 & sigma; point-source depths of & SIM;25.3-26.0 mag. COSMOS-Web will build on the rich heritage of multiwavelength observations and data products available in the COSMOS field. The design of COSMOS-Web is motivated by three primary science goals: (1) to discover thousands of galaxies in the Epoch of Reionization (6 & LSIM; z & LSIM; 11) and map reionization's spatial distribution, environments, and drivers on scales sufficiently large to mitigate cosmic variance, (2) to identify hundreds of rare quiescent galaxies at z > 4 and place constraints on the formation of the universe's most-massive galaxies (M (⋆) > 10(10) M (& ODOT;)), and (3) directly measure the evolution of the stellar-mass-to-halo-mass relation using weak gravitational lensing out to z & SIM; 2.5 and measure its variance with galaxies' star formation histories and morphologies. In addition, we anticipate COSMOS-Web's legacy value to reach far beyond these scientific goals, touching many other areas of astrophysics, such as the identification of the first direct collapse black hole candidates, ultracool subdwarf stars in the Galactic halo, and possibly the identification of z > 10 pair-instability supernovae. In this paper we provide an overview of the survey's key measurements, specifications, goals, and prospects for new discovery.

Synopsis Few animal groups can claim the level of wonder that cephalopods instill in the minds of researchers and the general public. Much of cephalopod biology, however, remains unexplored: the largest invertebrate brain, difficult husbandry conditions, and complex (meta-)genomes, among many other things, have hindered progress in addressing key questions. However, recent technological advancements in sequencing, imaging, and genetic manipulation have opened new avenues for exploring the biology of these extraordinary animals. The cephalopod molecular biology community is thus experiencing a large influx of researchers, emerging from different fields, accelerating the pace of research in this clade. In the first post-pandemic event at the Cephalopod International Advisory Council (CIAC) conference in April 2022, over 40 participants from all over the world met and discussed key challenges and perspectives for current cephalopod molecular biology and evolution. Our particular focus was on the fields of comparative and regulatory genomics, gene manipulation, single-cell transcriptomics, metagenomics, and microbial interactions. This article is a result of this joint effort, summarizing the latest insights from these emerging fields, their bottlenecks, and potential solutions. The article highlights the interdisciplinary nature of the cephalopod-omics community and provides an emphasis on continuous consolidation of efforts and collaboration in this rapidly evolving field.

Deep, multiband observations of high Galactic latitude fields are an essential tool for studying topics ranging from Galactic structure to extragalactic background radiation. The Hubble Deep Field (HDF-N) observations obtained in 1995 December established a standard for such narrow, deep surveys. The held has been extensively analyzed by a variety of groups and has been widely studied with imaging and spectroscopy over wavelengths ranging from 10(-3) to 2 x 10(5) mum. We describe here a second deep field campaign (HDF-S), this time in the southern hemisphere, undertaken by the Hubble Space Telescope (HST) in 1998 October in a program very similar to the northern Hubble Deep Field. Imaging and spectroscopy of three adjacent fields in the southern continuous viewing zone were obtained simultaneously for 150 orbits, and a mosaic of flanking fields was imaged for 27 additional orbits. Two important features of the HDF-S distinguish it from the HDF-N: the campaign included parallel observations by the three main HST instruments-WFPC2, STIS, and NICMOS-and the HDF-S location was selected to place a bright z = 2.24 quasar in the STIS field of view. The HDF-S observations consist of WVFPC2 images in filters close to U, B, y, and I, a deep STIS image of the held surrounding the quasar, spectroscopy of the quasar with STIS from 1150 to 3560 Angstrom and deep imaging of an adjacent field with NICMOS camera 3 at 1.1, 1.6, and 2.2 mum. All of the HDF-S data were fully reduced and made publicly available within 2 months of the observations, and we describe here the selection of the fields and the observing strategy that was employed. Detailed descriptions of the data and the reduction techniques for each field, together with the corresponding source catalogs, appear in separate papers.

Near-infrared (JHK) images of the giant HII region 30 Doradus were obtained. The overall stellar and extended appearance in the near infrared coincides with the optical morphology. However, several highly reddened objects are found in these images, some of them corresponding to previously reported "protostars", while others seem to be new tracers of recent massive star formation. In particular, we present a new infrared cluster to the NE and a chain of knot-like features apparently associated with an extended structure to the SW of the central cluster, both of which coincide with far-infrared and intense CO emission peaks.

Intercomparisons of ground-based IR continuum and H-2 images with Hubble Space Telescope WFPC2 images of the 30 Dor Nebula reveal detailed structural relationships, which provide new information about current star formation there. Numerous stellar IR sources have been discovered in or near the bright nebular filaments west and northeast of R136; their locations are intimately connected with the nebular microstructures, as well as with early O stars in dense nebular knots whose optical spectral classifications indicate extreme youth. The H-2 emission predominates in the dust clouds beyond the bright nebulosity and IR sources with respect to R136. The emerging picture suggests that a new stellar generation is being triggered by the energetic activity of the massive central cluster in the remanent interstellar material around its periphery. 30 Dor will likely evolve into a giant shell H II region similar to N11 in the LMC, containing an older association inside an evacuated central cavity, which is surrounded by H II regions ionized by a younger population. Such "two-stage starbursts" may be characteristic of massive-star formation on this scale.

The second largest H II region in the Large Magellanic Cloud, N11B has been surveyed in the near-IR. We present JHK(s) images of the N11B nebula. These images are combined with CO (1 --> 0) emission-line data and with archival New Technology Telescope and Hubble Space Telescope WFPC2 optical images to address the star formation activity of the region. IR photometry of all the IR sources detected is given. We confirm that a second generation of stars is currently forming in the N11B region. Our IR images show the presence of several bright IR sources that appear to be located toward the molecular cloud as seen from the CO emission in the area. Several of these sources show IR colors with young stellar object characteristics, and they are prime candidates to be intermediate-mass Herbig Ae/Be stars. For the first time, an extragalactic methanol maser is directly associated with IR sources embedded in a molecular core. Two IR sources are found at 2" (0.5 pc) of the methanol maser reported position. Additionally, we present the association of the N11A compact H II region to the molecular gas, where we find that the young massive O stars have eroded a cavity in the parental molecular cloud, typical of a champagne flow. The N11 region turns out to be a very good laboratory for studying the interaction of winds, UV radiation, and molecular gas. Several photodissociation regions are found.