744 research outputs found

    International Space Station United States Orbital Segment Oxygen Generation System On-Orbit Operational Experience

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    The International Space Station (ISS) United States Orbital Segment (USOS) Oxygen Generation System (OGS) was originally intended to be installed in ISS Node 3. The OGS rack delivery was accelerated, and it was launched to ISS in July of 2006 and installed in the US Laboratory Module. Various modification kits were installed to provide its interfaces, and the OGS was first activated in July of 2007 for 15 hours, In October of 2007 it was again activated for 76 hours with varied production rates and day/night cycling. Operational time in each instance was limited by the quantity of feedwater in a Payload Water Reservoir (PWR) bag. Feedwater will be provided by PWR bag until the USOS Water Recovery System (WRS) is delivered to SS in fall of 2008. This paper will discuss operating experience and characteristics of the OGS, as well as operational issues and their resolution

    Characteristics of music teachers and the progress of young instrumentalists

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    This study investigated the role of some key characteristics of teachers in the development of musical ability. Interviewing 257 children who differed in the extent of their instrumental mastery, it was discovered that the most successful learners regarded their teachers differently to those children who ceased music tuition. The more successful learners rated their first teacher higher than other learners on personal dimensions such as friendliness, and rated their current teacher higher than other learners on task-oriented professional dimensions such as pushiness. Additionally, the highly successful learners studied, on average, with more teachers than the other learners. These learners also generally received more individual instruction than the children who eventually ceased lessons. These findings confirm the importance of matching teacher characteristics to the changing requirements of learners in enabling the development of high levels of musical expertise

    The role of parental influences in the development of musical performance

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    Interviews were conducted with 257 children and their parents; all of the children had studied a musical instrument but differed in the extent of their mastery. The purpose of the study was to investigate the role of parents in the development of musical ability. It was discovered that the most successful children had parents who were the most highly involved in lessons and practice in the earliest stages of learning. These successful music learners often had parents who were involved with music themselves. Parental involvement in music typically took the form of listening to music rather than performing it, and tended to increase over the child's learning period. The children who failed to continue with lessons had parents who were, on average, less interested in music and who did not change their own degree of involvement with music over their child's learning period. Overall, the most musically able children had the highest levels of parental support

    Relative Abundance of Bacillus spp., Surfactant-Associated Bacterium Present in a Natural Sea Slick Observed by Satellite SAR Imagery over the Gulf of Mexico

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    The damping of short gravity-capillary waves (Bragg waves) due to surfactant accumulation under low wind speed conditions results in the formation of natural sea slicks. These slicks are detectable visually and in synthetic aperture radar satellite imagery. Surfactants are produced by natural life processes of many marine organisms, including bacteria, phytoplankton, seaweed, and zooplankton. In this work, samples were collected in the Gulf of Mexico during a research cruise on the R/V F.G. Walton Smith to evaluate the relative abundance of Bacillus spp., surfactant-associated bacteria, in the sea surface microlayer compared to the subsurface water at 0.2 m depth. A method to reduce potential contamination of microlayer samples during their collection on polycarbonate filters was implemented and advanced, including increasing the number of successive samples per location and changing sample storage procedures. By using DNA analysis (real-time polymerase chain reaction) to target Bacillus spp., we found that in the slick areas, these surfactant-associated bacteria tended to reside mostly in subsurface waters, lending support to the concept that the surfactants they may produce move to the surface where they accumulate under calm conditions and enrich the sea surface microlayer

    Relative Abundance of Bacillus spp., Surfactant-Associated Bacterium Present in a Natural Sea Slick Observed by Satellite SAR Imagery over the Gulf of Mexico

    Get PDF
    The damping of short gravity-capillary waves (Bragg waves) due to surfactant accumulation under low wind speed conditions results in the formation of natural sea slicks. These slicks are detectable visually and in synthetic aperture radar satellite imagery. Surfactants are produced by natural life processes of many marine organisms, including bacteria, phytoplankton, seaweed, and zooplankton. In this work, samples were collected in the Gulf of Mexico during a research cruise on the R/V F.G. Walton Smith to evaluate the relative abundance of Bacillus spp., surfactant-associated bacteria, in the sea surface microlayer compared to the subsurface water at 0.2 m depth. A method to reduce potential contamination of microlayer samples during their collection on polycarbonate filters was implemented and advanced, including increasing the number of successive samples per location and changing sample storage procedures. By using DNA analysis (real-time polymerase chain reaction) to target Bacillus spp., we found that in the slick areas, these surfactant-associated bacteria tended to reside mostly in subsurface waters, lending support to the concept that the surfactants they may produce move to the surface where they accumulate under calm conditions and enrich the sea surface microlayer

    Analysis of surfactant-associated bacteria in the sea surface microlayer using deoxyribonucleic acid sequencing and synthetic aperture radar

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    The sea surface microlayer (SML) is the upper 1 mm of the ocean, where Earth’s biogeochemical processes occur between the ocean and atmosphere. It is physicochemically distinct from the water below and highly variable in space and time due to changing physical conditions. Some microorganisms influence the composition of the SML by producing surfactants for biological functions that accumulate on the surface, decrease surface tension, and create slicks. Slicks can be visible to the eye and in synthetic aperture radar (SAR) satellite imagery. This study focuses on surfactant-associated bacteria in the near-surface layer and their role in slick formation where oil is present

    Osteogenic lineage restriction by osteoprogenitors cultured on nanometric grooved surfaces – the role of focal adhesion maturation

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    The differentiation of progenitor cells is dependent on more than biochemical signalling. Topographical cues in natural bone extracellular matrix guide cellular differentiation through the formation of focal adhesions, contact guidance, cytoskeletal rearrangement and ultimately gene expression. Osteoarthritis and a number of bone disorders present as growing challenges for our society. Hence, there is a need for next generation implantable devices to substitute for, or guide, bone repair in vivo. Cellular responses to nanometric topographical cues need to be better understood in vitro in order to ensure the effective and efficient integration and performance of these orthopaedic devices. In this study, the FDA approved plastic polycaprolactone, was embossed with nanometric grooves and the response of primary and immortalised osteoprogenitor cells observed. Nanometric groove dimensions were 240 nm or 540 nm deep and 12.5 μm wide. Cells cultured on test surfaces followed contact guidance along the length of groove edges, elongated along their major axis and showed nuclear distortion, they formed more focal complexes and a lower proportions of mature adhesions relative to planar controls. Down-regulation of the osteoblast marker genes RUNX2 and BMPR2 in primary and immortalised cells was observed on grooved substrates. Down-regulation appeared to directly correlate with focal adhesion maturation, indicating the involvement of ERK 1/2 negative feedback pathways following integrin mediated FAK activation
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