2,867 research outputs found
Black girls navigate the physical and emotional landscape of the neighbourhood: Normalized violence and strategic agency
This article considers how young Black women living in gang-affected neighbourhoods in an urban area in England, UK navigate their safety in public and private spaces, and how these spaces overlap and intersect. Drawing on a project with 18 participants aged 14â19, the research seeks to understand how the participants inhabit, navigate and strategize for their safety through their narratives of life and survival in an unsafe neighbourhood. Findings indicate that they experience sexual harassment in public spaces and gang-associated sexual and physical violence as common, accepted aspects of their everyday realities, from as young as 12. The narratives suggest that participants navigate complex friendship groups to protect each other and their families through tight codes of trust, secrecy, privacy and conflict-management strategies. This article seeks to bring attention to how young women utilize their agency to illuminate the coping strategies they draw on to navigate their physical environments. The article concludes with a discussion of the implications for interventions
P05-10. Sequential Immunization with a Subtype B HIV-1 Envelope Quasispecies Elicits Broader Neutralization than Vaccination with a Single Envelope Clone
Developing an integrated BIM/LCA framework to assess the sustainability of using earthen architecture
Robotic Extrusion of Algae-Laden Hydrogels for Large-Scale Applications
A bioprinting technique for largeâscale, customâprinted immobilization of microalgae is developed for potential applications within architecture and the built environment. Alginateâbased hydrogels with various rheology modifying polymers and varying water percentages are characterized to establish a window of operation suitable for layerâbyâlayer deposition on a large scale. Hydrogels formulated with methylcellulose and carrageenan, with water percentages ranging from 80% to 92.5%, demonstrate a dominant viscoelastic solidâlike property with GâČ > Gâł and a low phase angle, making them the most suitable for extrusionâbased printing. A custom multimaterial pneumatic extrusion system is developed to be attached on the end effector of an industrial multiaxis robot arm, allowing precisionâbased numerically controlled layered deposition of the viscous hydrogel. The relationship between the various printing parameters, namely air pressure, material viscosity, viscoelasticity, feed rate, printing distance, nozzle diameter, and the speed of printing, are characterized to achieve the desired resolution of the component. Printed prototypes are postcured in CaCl2 via crosslinking. Biocompatibility tests show that cells can survive for 21 days after printing the constructs. To demonstrate the methodology for scaleâup, a 1000 Ă 500 mm fibrous hydrogel panel is additively deposited with 3 different hydrogels with varying water percentages
XANES and Mg isotopic analyses of spinels in Ca-Al-rich inclusions: Evidence for formation under oxidizing conditions
Ti valence measurements in MgAl_2O_4 spinel from calcium-aluminum-rich inclusions (CAIs) by X-ray absorption near-edge structure (XANES) spectroscopy show that many spinels have predominantly tetravalent Ti, regardless of host phases. The average spinel in Allende type B1 inclusion TS34 has 87% Ti^(+4). Most spinels in fluffy type A (FTA) inclusions also have high Ti valence. In contrast, the rims of some spinels in TS34 and spinel grain cores in two Vigarano type B inclusions have larger amounts of trivalent titanium. Spinels from TS34 have approximately equal amounts of divalent and trivalent vanadium. Based on experiments conducted on CAI-like compositions over a range of redox conditions, both clinopyroxene and spinel should be Ti^(+3)-rich if they equilibrated with CAI liquids under near-solar oxygen fugacities. In igneous inclusions, the seeming paradox of high-valence spinels coexisting with low-valence clinopyroxene can be explained either by transient oxidizing conditions accompanying low-pressure evaporation or by equilibration of spinel with relict Ti^(+4)-rich phases (e.g., perovskite) prior to or during melting. Ion probe analyses of large spinel grains in TS34 show that they are enriched in heavy Mg, with an average Î^(25)Mg of 4.25 ± 0.028â°, consistent with formation of the spinel from an evaporating liquid. Î^(25)Mg shows small, but significant, variation, both within individual spinels and between spinel and adjacent melilite hosts. The Î^(25)Mg data are most simply explained by the low-pressure evaporation model, but this model has difficulty explaining the high Ti^(+4) concentrations in spinel
The Las Campanas IR Survey: Early Type Galaxy Progenitors Beyond Redshift One
(Abridged) We have identified a population of faint red galaxies from a 0.62
square degree region of the Las Campanas Infrared Survey whose properties are
consistent with their being the progenitors of early-type galaxies. The optical
and IR colors, number-magnitude relation and angular clustering together
indicate modest evolution and increased star formation rates among the
early-type field population at redshifts between one and two. The counts of red
galaxies with magnitudes between 17 and 20 rise with a slope that is much
steeper than that of the total H sample. The surface density of red galaxies
drops from roughly 3000 per square degree at H = 20.5, I-H > 3 to ~ 20 per
square degree at H = 20, I-H > 5. The V-I colors are approximately 1.5
magnitudes bluer on average than a pure old population and span a range of more
than three magnitudes. The colors, and photometric redshifts derived from them,
indicate that the red galaxies have redshift distributions adequately described
by Gaussians with sigma_z ~ 0.2V-I3$ are primarily in the 1.5 < z < 2
range. We find co-moving correlation lengths of 9-10 Mpc at z ~ 1, comparable
to, or larger than, those found for early-type galaxies at lower redshifts. A
simple photometric evolution model reproduces the counts of the red galaxies,
with only a ~ 30% decline in the underlying space density of early-type
galaxies at z ~ 1.2. We suggest on the basis of the colors, counts, and
clustering that these red galaxies are the bulk of the progenitors of present
day early-type galaxies.Comment: 5 pages, 3 figures, accepted for publication in the ApJ Letter
The Las Campanas Infrared Survey. III. The H-band Imaging Survey and the Near-Infrared and Optical Photometric Catalogs
(Abridged) The Las Campanas Infrared Survey, based on broad-band optical and
near-infrared photometry, is designed to robustly identify a statistically
significant and representative sample of evolved galaxies at redshifts z>1. We
have completed an H-band imaging survey over 1.1 square degrees of sky in six
separate fields. The average 5 sigma detection limit in a four arcsecond
diameter aperture is H ~ 20. Here we describe the design of the survey, the
observation strategies, data reduction techniques, and object identification
procedures. We present sample near-infrared and optical photometric catalogs
for objects identified in two survey fields. We perform object detection in all
bandpasses and identify ~ 54,000 galaxies over 1,408 square arcminutes of sky
in the two fields. Of these galaxies, ~ 14,000 are detected in the H-band and ~
2,000 have the colors of evolved galaxies, I - H >3, at z > 1. We find that (1)
the differential number counts N(m) for the H-band detected objects has a slope
of 0.44 at H 19. In addition, we find that (2) the
differential number counts for the H detected red objects has a slope of 0.85
at H 20, with a mean surface density ~ 3,000 degree^{-2}
mag^{-1} at H=20. Finally, we find that (3) galaxies with red optical to
near-IR colors (I-H > 3) constitute ~ 20% of the H detected galaxies at H ~ 21,
but only 2% at H = 19. We show that red galaxies are strongly clustered, which
results in a strong field to field variation in their surface density.
Comparisons of observations and predictions based on various formation
scenarios indicate that these red galaxies are consistent with mildly evolving
early-type galaxies at z ~ 1, although with a significant amount of on-going
star formation as indicated by the large scatter in their V-I colors.Comment: 48 pages, 13 figures, accepted for publication in the Astrophysical
Journa
Tensile strengths of flocculated compacted unsaturated soils
Flocculating agents can be introduced to soils through a number of natural or anthropogenic processes. This paper investigates the effect of flocculant addition (aqueous calcium chloride (CaCl2)) on the tensile strengths of two soils of differing flocculation susceptibility. Tensile strengths were found using the Brazilian (direct splitting) test for a range of suction values. A decrease in tensile strength was found for a soil with high clay content, which was consistent with previous findings in the literature. However, the strength of the soil with lower clay content unexpectedly increased. Results were interpreted using the extended MohrâCoulomb (EMC) yield criterion fitted to data above the residual suction value. Changes in EMC parameters were used to infer changes in material behaviour on calcium chloride addition. Results have important implications for the design of geotechnical structures, for example engineered cover systems, exposed to flocculating conditions. </jats:p
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