6,942 research outputs found
The Integrated Sachs-Wolfe Signal from BOSS Super-Structures
Cosmic structures leave an imprint on the microwave background radiation
through the integrated Sachs-Wolfe effect. We construct a template map of the
linear signal using the SDSS-III Baryon Acoustic Oscillation Survey at redshift
0.43 < z < 0.65. We verify the imprint of this map on the Planck CMB
temperature map at the 97% confidence level and show consistency with the
density-temperature cross-correlation measurement. Using this ISW
reconstruction as a template we investigate the presence of ISW sources and
further examine the properties of the Granett-Neyrinck-Szapudi supervoid and
supercluster catalogue. We characterise the three-dimensional density profiles
of these structures for the first time and demonstrate that they are
significant structures. Model fits demonstrate that the supervoids are
elongated along the line-of-sight and we suggest that this special orientation
may be picked out by the void-finding algorithm in photometric redshift space.
We measure the mean temperature profiles in Planck maps from public void and
cluster catalogues. In an attempt to maximise the stacked ISW signal we
construct a new catalogue of super-structures based upon local peaks and
troughs of the gravitational potential. However, we do not find a significant
correlation between these structures and the CMB temperature.Comment: Updated to match journal articl
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An Ultrahigh-throughput Microfluidic Platform for Single-cell Genome Sequencing.
Sequencing technologies have undergone a paradigm shift from bulk to single-cell resolution in response to an evolving understanding of the role of cellular heterogeneity in biological systems. However, single-cell sequencing of large populations has been hampered by limitations in processing genomes for sequencing. In this paper, we describe a method for single-cell genome sequencing (SiC-seq) which uses droplet microfluidics to isolate, amplify, and barcode the genomes of single cells. Cell encapsulation in microgels allows the compartmentalized purification and tagmentation of DNA, while a microfluidic merger efficiently pairs each genome with a unique single-cell oligonucleotide barcode, allowing >50,000 single cells to be sequenced per run. The sequencing data is demultiplexed by barcode, generating groups of reads originating from single cells. As a high-throughput and low-bias method of single-cell sequencing, SiC-seq will enable a broader range of genomic studies targeted at diverse cell populations
Relationship Between the Foveal Avascular Zone and Foveal Pit Morphology
Purpose.To assess the relationship between foveal pit morphology and size of the foveal avascular zone (FAZ).
Methods. Forty-two subjects were recruited. Volumetric images of the macula were obtained using spectral domain optical coherence tomography. Images of the FAZ were obtained using either a modified fundus camera or an adaptive optics scanning light ophthalmoscope. Foveal pit metrics (depth, diameter, slope, volume, and area) were automatically extracted from retinal thickness data, whereas the FAZ was manually segmented by two observers to extract estimates of FAZ diameter and area.
Results. Consistent with previous reports, the authors observed significant variation in foveal pit morphology. The average foveal pit volume was 0.081 mm3 (range, 0.022 to 0.190 mm3). The size of the FAZ was also highly variable between persons, with FAZ area ranging from 0.05 to 1.05 mm2 and FAZ diameter ranging from 0.20 to 1.08 mm. FAZ area was significantly correlated with foveal pit area, depth, and volume; deeper and broader foveal pits were associated with larger FAZs.
Conclusions. Although these results are consistent with predictions from existing models of foveal development, more work is needed to confirm the developmental link between the size of the FAZ and the degree of foveal pit excavation. In addition, more work is needed to understand the relationship between these and other anatomic features of the human foveal region, including peak cone density, rod-free zone diameter, and Henle fiber layer
Orbital Parameter Determination for Wide Stellar Binary Systems in the Age of Gaia
The orbits of binary stars and planets, particularly eccentricities and
inclinations, encode the angular momentum within these systems. Within stellar
multiple systems, the magnitude and (mis)alignment of angular momentum vectors
among stars, disks, and planets probes the complex dynamical processes guiding
their formation and evolution. The accuracy of the \textit{Gaia} catalog can be
exploited to enable comparison of binary orbits with known planet or disk
inclinations without costly long-term astrometric campaigns. We show that
\textit{Gaia} astrometry can place meaningful limits on orbital elements in
cases with reliable astrometry, and discuss metrics for assessing the
reliability of \textit{Gaia} DR2 solutions for orbit fitting. We demonstrate
our method by determining orbital elements for three systems (DS Tuc AB, GK/GI
Tau, and Kepler-25/KOI-1803) using \textit{Gaia} astrometry alone. We show that
DS Tuc AB's orbit is nearly aligned with the orbit of DS Tuc Ab, GK/GI Tau's
orbit might be misaligned with their respective protoplanetary disks, and the
Kepler-25/KOI-1803 orbit is not aligned with either component's transiting
planetary system. We also demonstrate cases where \textit{Gaia} astrometry
alone fails to provide useful constraints on orbital elements. To enable
broader application of this technique, we introduce the python tool
\texttt{lofti\_gaiaDR2} to allow users to easily determine orbital element
posteriors.Comment: 18 pages, 10 figures, accepted for publication in Ap
A Study of the Hierarchical Culture Gaps Within Unionized Utilities Companies
The purpose of this study was to measure the culture gaps between hierarchical subgroups within unionized utilities companies. We conducted a mixed methods study. Using archival survey data, we compared hierarchically-defined subgroups’ perceptions of performance-linked culture traits within five unionized utilities companies. We later conducted interviews and focus groups, followed by qualitative coding and analysis. As compared to non-union employees, union employees viewed their companies as substantially less involving, consistent, adaptable, and clear about purpose and direction. Our qualitative analysis highlighted two prior management decisions as illustrative of the contrast between high and low levels of union involvement and clarity. Culture scholars and practitioners have suggested that leaders must align subcultures where they exist. Our study demonstrates large culture gaps between union employees and other subgroups and suggests that management’s involvement of the workforce in strategic decisions may have unique consequences for how subgroups perceive and interpret the culture
Miami- Dade Urban Tree Canopy Analysis
Two of the Florida state universities, University of Florida (UF) and Florida International University (FIU), collaborated in assessing urban tree cover (UTC) for part of northwestern Miami-Dade County, covering an area of approximately 380 km2 (147 mi2). The analysis estimated the area with current tree canopy (existing UTC), the area of potential tree canopy (possible UTC), and various other land cover categories. The assessment used two methods to establish those estimates. The first method utilized the i-Tree canopy assessment tool provided by the USDA Forest Service. The second method used a combination of multispectral satellite data and airborne Light Detection and Ranging (LiDAR) datasets for detection and classification of land cover. Classification results were further analyzed in a Geographic Information System (GIS) to relate land cover distribution patterns (obtained from the second land cover classification method) to surface temperatures, land use patterns, and socioeconomic factors
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