1,154 research outputs found

    Shuttle active thermal control system development testing. Volume 6: Water ejector plume tests

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    Results are given of vacuum testing of nozzles designed to eject water vapor away from the space shuttle to prevent contamination of the spacecraft surfaces and payload. The water vapor is generated by an active cooling system which evaporates excess fuel cell water to supplement a modular radiator system (MRS). The complete heat rejection system including the MRS, flash evaporator or sublimator and nozzle were first tested to demonstrate the system operational characteristics. The plume tests were performed in two phases and the objectives of this test series were: (1) to determine the effectiveness of a supersonic nozzle and a plugged nozzle in minimizing impingement upon the spacecraft of water vapor exhausted by an active device (flash evaporator or sublimator); and (2) to obtain basic data on the flow fields of exhaust plumes generated by these active devices, both with and without nozzles installed

    An assessment of the precision and confidence of aquatic eddy correlation measurements

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    The quantification of benthic fluxes with the aquatic eddy correlation (EC) technique is based on simultaneous measurement of the current velocity and a targeted bottom water parameter (e. g., O-2, temperature). High-frequency measurements (64Hz) are performed at a single point above the seafloor using an acoustic Doppler velocimeter (ADV) and a fast-responding sensor. The advantages of aquatic EC technique are that 1) it is noninvasive, 2) it integrates fluxes over a large area, and 3) it accounts for in situ hydrodynamics. The aquatic EC has gained acceptance as a powerful technique; however, an accurate assessment of the errors introduced by the spatial alignment of velocity and water constituent measurements and by their different response times is still needed. Here, this paper discusses uncertainties and biases in the data treatment based on oxygen EC flux measurements in a large-scale flume facility with well-constrained hydrodynamics. These observations are used to review data processing procedures and to recommend improved deployment methods, thus improving the precision, reliability, and confidence of EC measurements. Specifically, this study demonstrates that 1) the alignment of the time series based on maximum cross correlation improved the precision of EC flux estimations; 2) an oxygen sensor with a response time of <0.4 s facilitates accurate EC fluxes estimates in turbulence regimes corresponding to horizontal velocities <11 cm s(-1); and 3) the smallest possible distance (<1 cm) between the oxygen sensor and the ADV's sampling volume is important for accurate EC flux estimates, especially when the flow direction is perpendicular to the sensor's orientation

    Physical properties of methane-enriched plumes along the Hikurangi margin of New Zealand: Thoughts on sources and life spans of water column methane anomalies

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    We explored methane distribution and physical mixing processes at active areas with CTD measurements utilizing a methane sensor combined with discrete water samples collected in Niskin bottles (24 bottle carrousel). Evidence of a methane plume injection was obtained during a CTD cast. The plume injection is thought to be the result of a vertical advective flow driven by a source of buoyancy (e.g., heat flux, bubbles, high dissolved methane concentration). Thorpe scale analyses on the high-resolution temperature data allow us to locate turbulent overturns and the associated small- to large-scale temperature inversions. Thorpe displacement analysis shows substantial overturns of ca. 30 m at around 720 m depth that perfectly correspond with a large peak (ca. 600 nM) of methane. This is likely the final intrusion depth of a methane plume originating from the sea floor. However, it is inconclusive which buoyancy source(s) are driving the plume (e.g. heat flux, bubbles, etc.). In the corresponding profiles, a completely well-mixed ca. 35 m thick layer (in T and Sal) is observed at this location. This further suggests a local buoyancy source. Substantial energy input is required to maintain such a well-mixed structure. In absence of a supporting energy source, this signal would be vertically diffusively smeared within several days (t = z/Kz), and much faster horizontally. Energy balances suggest that the source and resulting upwelling are a dissolved methane-enriched thermal plume, as the number of bubbles required to produce such a plume and maintain the deep-mixed layer is too substantial

    Submarine flatulence along the Hikurangi margin of New Zealand: Linking geochemical methane anomalies in the water column with hydroacoustic evidence of bubble transport

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    High methane concentrations of up to 3200 nM have been measured in the water column along the Hikurangi margin. The methane is a manifestation of common and wide spread cold fluid seepage that is linked to considerable gas hydrate resources. Three methods were utilised to explore for active seeps: by continuous, qualitative measurement of dissolved methane gas in the water column, using a methane sensor (METS) which was attached to a CTD; by qualitative measurement of discrete water samples collected in niskin bottles on the CTD; and by hydroacoustic detection of gas bubbles with a single beam echosounder. Prior to cruises on the TANGAROA RV in 2006 and the SONNE RV in 2007, only a few studies have been performed in this region. Here we present data of methane distribution from three different seep locations along the Hikurangi Margin. The Rock Garden seep site is in the northern part of the Hikurangi margin and occurs at the gas hydrate stability boundary (about 700m water depth in this area). The Omakere Ridge site is also in the northern Hikurangi margin, but occurs within deeper waters (1200m). The Wairarapa area is in the southern Hikurangi margin and is only 6 miles offshore (about 1200m depth) in the Cook Strait. Qualitative methane data have been obtained by onboard GC-based analyses using head-space equilibrium and vacuum extraction methods. The ability to define and corroborate by direct measurement, narrow (10-15m wide) methane anomalies in the water column was made possible only by the availability of a very responsive METS. Hydroacoustic flare imaging shows that bubble release is a common process at almost all of the 12 studied seep sites. Particularly at Rock Garden, ROV observations show pulsed bubble release with outbursts lasting minutes. The fate of methane along the Hikurangi margin will be discussed based on CTD-cast sections across seep sites and detailed sampling at seeps and in flares. The results are linked with bubble dissolution models, incorporating ADCP current data, physical water column properties, bubble-induced advection as studied by thermistor-moorings and knowledge about currents and eddies in the area

    QuShape: Rapid, accurate, and best-practices quantification of nucleic acid probing information, resolved by capillary electrophoresis

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    Chemical probing of RNA and DNA structure is a widely used and highly informative approach for examining nucleic acid structure and for evaluating interactions with protein and small-molecule ligands. Use of capillary electrophoresis to analyze chemical probing experiments yields hundreds of nucleotides of information per experiment and can be performed on automated instruments. Extraction of the information from capillary electrophoresis electropherograms is a computationally intensive multistep analytical process, and no current software provides rapid, automated, and accurate data analysis. To overcome this bottleneck, we developed a platform-independent, user-friendly software package, QuShape, that yields quantitatively accurate nucleotide reactivity information with minimal user supervision. QuShape incorporates newly developed algorithms for signal decay correction, alignment of time-varying signals within and across capillaries and relative to the RNA nucleotide sequence, and signal scaling across channels or experiments. An analysis-by-reference option enables multiple, related experiments to be fully analyzed in minutes. We illustrate the usefulness and robustness of QuShape by analysis of RNA SHAPE (selective 2′-hydroxyl acylation analyzed by primer extension) experiments

    A structured approach to VO reconfigurations through Policies

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    One of the strength of Virtual Organisations is their ability to dynamically and rapidly adapt in response to changing environmental conditions. Dynamic adaptability has been studied in other system areas as well and system management through policies has crystallized itself as a very prominent solution in system and network administration. However, these areas are often concerned with very low-level technical aspects. Previous work on the APPEL policy language has been aimed at dynamically adapting system behaviour to satisfy end-user demands and - as part of STPOWLA - APPEL was used to adapt workflow instances at runtime. In this paper we explore how the ideas of APPEL and STPOWLA can be extended from workflows to the wider scope of Virtual Organisations. We will use a Travel Booking VO as example.Comment: In Proceedings FAVO 2011, arXiv:1204.579

    Characteristics of Family Lives in Central Europe

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    In this chapter, authors give a picture of families in individual countries, which participated in the survey, so from the Czech Republic, Slovakia, Germany, Poland, Ukraine and Latvia. They pay attentionmainly to the family changes after the year 1990. There is mainly demographic situation. Furthermore, there are features which present contemporary family such as an increase of democratization in family coexistence in connection with the shifts of roles and disintegration in a family life linked with overall individualism manifested by automation, where one creates his/her own way of life. The contemporary family is more likely affected in all countries by progressive social differentiation; in a different level of unemployment, certain isolation and changes are always seen in intergeneration relationships. The authors also pay attention to family social policy and housing situation when starting a family

    Genomic structure and alterations of homeobox gene CDX2 in colorectal carcinomas

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    Expression of CDX2, a caudal-related homeobox gene, was found to be decreased in colorectal carcinomas. Heterozygous null mutant mice as to Cdx2 develop multiple intestinal adenomatous polyps. To clarify the role of CDX2 in colorectal carcinogenesis, we determined its genomic structure, and searched for mutations of CDX2 in 49 sporadic colorectal carcinomas and ten hereditary non-polyposis colorectal cancers (HNPCC) without microsatellite instability. None of them exhibited a mutation. We further examined 19 HNPCC carcinomas with microsatellite instability for mutations in a (G)7 repeat site within CDX2. One of them (5.3%) exhibited one G insertion. Loss of heterozygosity was observed in 2 of the 20 (10%) informative sporadic carcinomas, and in one of the three (33.3%) informative HNPCC cancers. These data indicate that CDX2 may play only a minor role in colorectal carcinogenesis. © 1999 Cancer Research Campaig

    Screening non-coding RNAs in transcriptomes from neglected species using PORTRAIT: case study of the pathogenic fungus Paracoccidioides brasiliensis

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    <p>Abstract</p> <p>Background</p> <p>Transcriptome sequences provide a complement to structural genomic information and provide snapshots of an organism's transcriptional profile. Such sequences also represent an alternative method for characterizing neglected species that are not expected to undergo whole-genome sequencing. One difficulty for transcriptome sequencing of these organisms is the low quality of reads and incomplete coverage of transcripts, both of which compromise further bioinformatics analyses. Another complicating factor is the lack of known protein homologs, which frustrates searches against established protein databases. This lack of homologs may be caused by divergence from well-characterized and over-represented model organisms. Another explanation is that non-coding RNAs (ncRNAs) may be caught during sequencing. NcRNAs are RNA sequences that, unlike messenger RNAs, do not code for protein products and instead perform unique functions by folding into higher order structural conformations. There is ncRNA screening software available that is specific for transcriptome sequences, but their analyses are optimized for those transcriptomes that are well represented in protein databases, and also assume that input ESTs are full-length and high quality.</p> <p>Results</p> <p>We propose an algorithm called PORTRAIT, which is suitable for ncRNA analysis of transcriptomes from poorly characterized species. Sequences are translated by software that is resistant to sequencing errors, and the predicted putative proteins, along with their source transcripts, are evaluated for coding potential by a support vector machine (SVM). Either of two SVM models may be employed: if a putative protein is found, a protein-dependent SVM model is used; if it is not found, a protein-independent SVM model is used instead. Only <it>ab initio </it>features are extracted, so that no homology information is needed. We illustrate the use of PORTRAIT by predicting ncRNAs from the transcriptome of the pathogenic fungus <it>Paracoccidoides brasiliensis </it>and five other related fungi.</p> <p>Conclusion</p> <p>PORTRAIT can be integrated into pipelines, and provides a low computational cost solution for ncRNA detection in transcriptome sequencing projects.</p

    Phos-Tag-Based Analysis of Myosin Regulatory Light Chain Phosphorylation in Human Uterine Myocytes

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    The 'phosphate-binding tag' (phos-tag) reagent enables separation of phospho-proteins during SDS-PAGE by impeding migration proportional to their phosphorylation stoichiometry. Western blotting can then be used to detect and quantify the bands corresponding to the phospho-states of a target protein. We present a method for quantification of data regarding phospho-states derived from phos-tag SDS-PAGE. The method incorporates corrections for lane-to-lane loading variability and for the effects of drug vehicles thus enabling the comparison of multiple treatments by using the untreated cellular set-point as a reference. This method is exemplified by quantifying the phosphorylation of myosin regulatory light chain (RLC) in cultured human uterine myocytes.We have evaluated and validated the concept that, when using an antibody (Ab) against the total-protein, the sum of all phosphorylation states in a single lane represents a 'closed system' since all possible phospho-states and phosphoisotypes are detected. Using this approach, we demonstrate that oxytocin (OT) and calpeptin (Calp) induce RLC kinase (MLCK)- and rho-kinase (ROK)-dependent enhancements in phosphorylation of RLC at T18 and S19. Treatment of myocytes with a phorbol ester (PMA) induced phosphorylation of S1-RLC, which caused a mobility shift in the phos-tag matrices distinct from phosphorylation at S19.We have presented a method for analysis of phospho-state data that facilitates quantitative comparison to a reference control without the use of a traditional 'loading' or 'reference' standard. This analysis is useful for assessing effects of putative agonists and antagonists where all phospho-states are represented in control and experimental samples. We also demonstrated that phosphorylation of RLC at S1 is inducible in intact uterine myocytes, though the signal in the resting samples was not sufficiently abundant to allow quantification by the approach used here
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