80 research outputs found

    X-band solid state signal source special report

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    X-band solid state signal source microwave apparatu

    ERTS-1 Virgin Islands experiment 589: Determine boundaries of ERTS and aircraft data within which useful water quality information can be obtained

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    The author has identified the following significant results. The boundaries of application of ERTS-1 and aircraft data are established for St. Thomas harbor within which useful water quality information can be obtained. In situ physical, chemical, and biological water quality and benthic data were collected. Moored current meters were employed. Optical measurements of solar irradiance, color test panel radiance and water absorption were taken. Procedures for correlating in situ optical, biological, and chemical data with underflight aircraft I2S data and ERTS-1 MSS scanner data are presented. Comparison of bulk and precision CCT computer printout data for this application is made, and a simple method for geometrically locating bulk data individual pixels based on land-water interface is described. ERTS spacecraft data and I2S aircraft imagery are correlated with optical in situ measurements of the harbor water, with the aircraft green photographic and ERTS-1 MSS-4 bands being the most useful. The biological pigments correlate inversely with the optical data for inshore areas and directly further seaward. Automated computer data processing facilitated analysis

    On the Use of Benthic Foraminifera as Sediment Tracers in a Hawaiian Bay

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    Populations of foraminifera were investigated in regard to the suitability of the various species as indicators of sand transport. Of 53 species recorded in the sediments of Kahana Bay, Oahu, 16 showed distribution patterns that give evidence of the direction of sand transport within the littoral cell

    Study of lunar landing sensor performance final report

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    Lunar landing sensor performance - extended range altimeter, short range velocity sensor, and beacon tracking rada

    Greater Forearm Blood Flow is Associated With Higher Physical Activity in Older Individuals

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    Please refer to the pdf version of the abstract located adjacent to the title

    Inter- and Intra-household Perceived Relative Inequality Among Disabled and Non-disabled People in Liberia

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    Evidence suggests that people with disabilities are the most marginalised and vulnerable group within any population. However, little is known about the extent of inequality between people with and without disabilities in contexts where the majority of persons experience extreme poverty and hardship. This includes in Liberia, where very little is understood about the lives of disabled people in general. This study uses a multidimensional wellbeing framework to understand perceived relative inequality associated with disability by assessing several facets of wellbeing across and within households containing disabled members (N = 485) or households with no disabled members (N = 538) in Liberian communities (Total individuals surveyed, N = 2020). Statistical comparisons (adjusted for age, sex, education and wealth differences and clustered at the household, village and county level) reveal that disabled Liberians are managing similarly to non-disabled Liberians in terms of income and education, but experience many perceived relative inequalities including in life satisfaction, transport access, political participation and social inclusion. Our results further suggest that disability may lead to perceived relative inequality at the household level in terms of trust held in neighbours. However, they also show that being the head of a household may protect against perceived relative inequality in certain dimensions (e.g. healthcare and transport access, political participation) irrespective of disability status. Results are discussed in terms of practical implications for development efforts in Liberia and for disabled people in other low- and middle-income settings

    Sea surface temperature changes in the southern California borderlands during the last glacial-interglacial cycle

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    A variety of evidence suggests that average sea surface temperatures (SSTs) during the last glacial maximum in the California Borderlands region were significantly colder than during the Holocene. Planktonic foraminiferal δ18O evidence and average SST estimates derived by the modern analog technique indicate that temperatures were 6°-10°C cooler during the last glacial relative to the present. The glacial plankton assemblage is dominated by the planktonic foraminifer Neogloboquadrina pachyderma (sinistral coiling) and the coccolith Coccolithus pelagicus, both of which are currently restricted to subpolar regions of the North Pacific. The glacial-interglacial average SST change determined in this study is considerably larger than the 2°C change estimated by Climate: Long-Range Investigation, Mapping, and Prediction (CLIMAP) [1981]. We propose that a strengthened California Current flow was associated with the advance of subpolar surface waters into the Borderlands region during the last glacial

    A resolution for the coiling direction paradox in Neogloboquadrina pachyderma.

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    We present new data on genotypic differences and biogeographic distribution of coiling types in the living planktonic foraminiferal morphospecies Neogloboquadrina pachyderma. The genetic evidence demonstrates that coiling direction in N. pachyderma is a genetic trait, heritable through time, and is not a morphological feature reflecting ecophenotypic variation. The two opposite coiling morphotypes appear to have diverged during the late Miocene, and they have distinctly different ecologies. In combination with fossil evidence, biogeography, and ecology the degree of genetic distinction between the two coiling types of N. pachyderma strongly implies that they should be considered different species. We propose the adoption of the widely recognized name N. incompta for the right coiling morphospecies. The genetic evidence also demonstrates a low level (<3%) of aberrant coiling associated with both morphotypes. The abundance of these aberrant specimens has no relationship with the environment. These findings have important consequences for the use of N. pachyderma and N. incompta as paleoceanographic signal carriers in polar and subpolar waters. Copyright 2006 by the American Geophysical Union

    Morphology of the Faial Island shelf (Azores): the interplay between volcanic, erosional, depositional, tectonic and mass-wasting processes

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    [1] The extents of volcanic island shelves result from surf erosion, which enlarges them, and volcanic progradation, which reduces them. However, mass‐wasting, tectonics and sediment deposition also contribute to their morphology. In order to assess the relative significance of these various processes, we have mapped in detail Faial Island's shelf in the Azores archipelago based on interpretation of geophysical and geological data. The nearshore substrates of the island, down to 30–50 m depth, are rocky and covered by volcaniclastic boulder deposits formed by surf action on now‐submerged lava flows. Below those depths, sandy and gravel volcaniclastic beds dominate, building clinoforms up to the shelf edge. In some sectors of the coast, prograding lava has narrowed the shelf, but, in contrast to nearby Pico Island, we find fewer submarine‐emplaced lavas on the shelf. In this island, we interpret the distance between the coastline and the shelf edge as almost entirely a result of a straightforward competition between surf erosion and lava progradation, in which erosion dominates. Therefore shelf width can be used as a proxy for coastline age as well as for wave energy exposure. The stratigraphy of shelf deposits in boomer seismic data is examined in detail to assess the roles of different sediment sources, accommodation space and wave exposure in creating these deposits. We also show evidence of mass‐wasting at the shelf edge and discuss the possible origins of slope instability. Finally, we discuss the contributing role of tectonics for the development of the shelf.publishe

    Structure and serpentinization of the subducting Cocos plate offshore Nicaragua and Costa Rica

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    Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 12 (2011): Q06009, doi:10.1029/2011GC003592.The Cocos plate experiences extensional faulting as it bends into the Middle American Trench (MAT) west of Nicaragua, which may lead to hydration of the subducting mantle. To estimate the along strike variations of volatile input from the Cocos plate into the subduction zone, we gathered marine seismic refraction data with the R/V Marcus Langseth along a 396 km long trench parallel transect offshore of Nicaragua and Costa Rica. Our inversion of crustal and mantle seismic phases shows two notable features in the deep structure of the Cocos plate: (1) Normal oceanic crust of 6 km thickness from the East Pacific Rise (EPR) lies offshore Nicaragua, but offshore central Costa Rica we find oceanic crust from the northern flank of the Cocos Nazca (CN) spreading center with more complex seismic velocity structure and a thickness of 10 km. We attribute the unusual seismic structure offshore Costa Rica to the midplate volcanism in the vicinity of the Galápagos hot spot. (2) A decrease in Cocos plate mantle seismic velocities from ∼7.9 km/s offshore Nicoya Peninsula to ∼6.9 km/s offshore central Nicaragua correlates well with the northward increase in the degree of crustal faulting outboard of the MAT. The negative seismic velocity anomaly reaches a depth of ∼12 km beneath the Moho offshore Nicaragua, which suggests that larger amounts of water are stored deep in the subducting mantle lithosphere than previously thought. If most of the mantle low velocity zone can be interpreted as serpentinization, the amount of water stored in the Cocos plate offshore central Nicaragua may be about 2.5 times larger than offshore Nicoya Peninsula. Hydration of oceanic lithosphere at deep sea trenches may be the most important mechanism for the transfer of aqueous fluids to volcanic arcs and the deeper mantle.This work was funded by the U.S. National Science Foundation MARGINS program under grants OCE0405556, OCE 0405654, and OCE 0625178
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