421 research outputs found

    Final shuttle-derived atmospheric database: Development and results from thirty-two flights

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    The final Shuttle-derived atmospheric data base is presented. The relational data base is comprised of data from 32 Space Transportation System (STS) descent flights, to include available meteorology data taken in support of each flight. For the most part, the available data are restricted to the middle atmosphere. In situ accelerations, sensed by the tri-redundant Inertial Measurement Unit (IMU) to an accuracy better than 1 mg, are combined with post-flight Best Estimate Trajectory (BET) information and predicted, flight-substantiated Orbiter aerodynamics to provide determinations up to altitudes of 95 km. In some instances, alternate accelerometry data with micro-g resolution were utilized to extend the data base well into the thermosphere. Though somewhat limited, the ensemble of flights permit a reasonable sampling of monthly, seasonal, and latitudinal variations which can be utilized for atmospheric science investigations and model evaluations and upgrades as appropriate. More significantly, the unparallel vertical resolution in the Shuttle-derived results indicate density shears normally associated with internal gravity waves or local atmospheric instabilities. Consequently, these atmospheres can also be used as stress-atmospheres for Guidance, Navigation and Control (GN and C) system development and analysis as part of any advanced space vehicle design activities

    Final STS-35 Columbia descent BET products and results for LaRC OEX investigations

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    Final STS-35 'Columbia' descent Best Estimate Trajectory (BET) products have been developed for Langley Research Center (LaRC) Orbiter Experiments (OEX) investigations. Included are the reconstructed inertial trajectory profile; the Extended BET, which combines the inertial data and, in this instance, the National Weather Service atmospheric information obtained via Johnson Space Center; and the Aerodynamic BET. The inertial BET utilized Inertial Measurement Unit 1 (IMU1) dynamic measurements for deterministic propagation during the ENTREE estimation process. The final estimate was based on the considerable ground based C-band tracking coverage available as well as Tracking Data and Relay Satellite System (TDRSS) Doppler data, a unique use of the latter for endo-atmospheric flight determinations. The actual estimate required simultaneous solutions for the spacecraft position and velocity, spacecraft attitude, and six IMU parameters - three gyro biases and three accelerometer scale factor correction terms. The anchor epoch for this analysis was 19,200 Greenwich Mean Time (GMT) seconds which corresponds to an initial Shuttle altitude of approximately 513 kft. The atmospheric data incorporated were evaluated based on Shuttle derived considerations as well as comparisons with other models. The AEROBET was developed based on the Extended BET, the measured spacecraft configuration information, final mass properties, and the final Orbiter preoperation databook. The latter was updated based on aerodynamic consensus incrementals derived by the latest published FAD. The rectified predictions were compared versus the flight computed values and the resultant differences were correlated versus ensemble results for twenty-two previous STS entry flights

    Solids maldistribution in parallel cyclones

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    The amount of solids maldistribution in parallel cyclones was investigated to determine what parameters affected the maldistribution. In many fluidized bed processes with parallel cyclones (as many as 20 in parallel in some cases), it has been noted that unequal erosion (wear) can occur in the cyclones. This results in very short run lengths in order to repair the cyclones with the most wear. This unequal wear has been attributed to unequal solids distribution to the cyclones. In addition to the increased wear, cyclone efficiencies are affected as well. In the specific concern that generated this study, it was found that parallel cyclones in fluidized-bed cokers at Syncrude Canada Ltd. (Syncrude) had unequal amounts of coke buildup on them. This coke buildup on the cyclones causes increased backpressure on the fluidized-bed coker, and after a certain pressure is reached, results in shutdown of the coker. Hot scouring coke, presented at the cyclone inlets, is used to combat the coke formation that is caused by condensation of heavy hydrocarbons. Understanding the scouring coke distribution into the parallel cyclones could lead to reduced deposit maldistribution and increased run length. The testing to determine what causes solids maldistribution in parallel cyclones was conducted using four, 30-cm diameter parallel cyclones that were located above a 0.9-m diameter fluidized bed. Solids flows into the freeboard above the fluidized bed were from the fluidized bed itself and from two pneumatic conveying lines that simulated the lines entering the freeboard of the Syncrude Canada Ltd (Syncrude) fluidized bed coker. The testing was conducted at ambient temperature and pressure using a coke material with a median particle size of 156 microns. The results of the testing showed that although the pressure drop across the cyclones were essentially equal, the gas and solids flow rates through the cyclones could vary significantly. By closing a valve in the dipleg of each of the test cyclones and measuring the rate of buildup of solids in each dipleg, the solids flow rate through each cyclone could be determined. Tests were conducted to vary the gas flow rate through the bed, the amount of solids flow through each pneumatic conveying line and the amount of gas flowing through each cyclone. Depending on conditions, it was found that the ratio of the solids flow rate through the highest-loaded cyclone to the lowest-loaded cyclone could be as much as a factor of four. It was found that the solids distribution in the freeboard above the bed determined the solids flow distribution into each cyclone. Changing the gas flow rate through the cyclone did not affect the solids distribution through the cyclones. It appears that the solids distribute to the cyclones based on the solids distribution at the entrance to the parallel cyclones. The gas flow then distributes itself in order to equalize the pressure drop across the cyclones

    Analisis Framing Pemberitaan Kasus Dugaan Korupsi dan Gaya Hidup Mewah Gubernur Ratu Atut Chosiyah pada “Koran Tempo”

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    Modus korupsi sesungguhnya merupakan suatu manipulasi jabatan publik untuk keuntungan pribadi. Mereka menggunakan kewenangan menentukan kebijakan publik semata demi kepentingan sendiri. Peran KPK (Komisi Pemberantasan Korupsi) dan BPK ( Badan Pemeriksa Keuangan) dalam hal ini sangat berpengaruh untuk menghentikan laju pertumbuhan korupsi.Penelitian ini dilakukan untuk mengetahui pembingkaian (framing) berita koran Tempo terhadap kasus korupsi yang dilakukan oleh pejabat wanita terkait kasus dugaan korupsi dan gaya hidup mewah Ratu Atut Chosiyah. Dugaan kasus korupsi Ratu Atut banyak dimuat dalam media cetak maupun media televisi. Tempo terkenal keras pada kasus yang mengindikasi adanya praktik korupsi dan melibatkan kepentingan publik yang besar termasuk pejabat dan aparatur Negara. Tempo hingga kini mampu meliput beberapa kasus Atut baik dalam kasus korupsi maupun gaya hidup mewah Atut. Salah satu metode penelitian yang mampu menganalisis bagaimana realitas itu dibentuk dan dikonstruksi oleh media adalah analisis framing. Peneliti menggunakan analisa Framing yang diperkenalkan oleh Pan dan Kosicki. Obyek penelitian adalah pemberitaan kasus dugaan korupsi dan gaya hidup mewah Gubernur Ratu Atut Chosiyah yang muncul pada koran Tempodari tanggal 5 Okober 2013 sampai 13 November 2013.Hasil penelitian menunjukkan bahwa koran Tempo memberikan gambaran pemberitaan dengan menunjukan struktur Sintaksis, Skrip, Tematik, Dan Retoris. Struktr retoris dalam koran Tempo tampak menonjol karena wartawan koran Tempo banyak menggunakan istilah, leksikon, idiom, bahkan gambar karikatur yang dapat menarik perhatian khalayak. Koran Tempo terkenal dengan gaya pemberitaan yang kritis dan tajam serta memiliki volume dan frekuensi berita yang lengkap karena mampu memuat lebih dari satu pemberitaan dengan kasus yang sama dalam satu edisi. Koran Tempo dalam menuliskan pemberitaan tetap mengedepankan objektivitas dan netralitas, karena wartawan Tempo selalu menjaga agar sebuah karya tetap bermutu tinggi dan berpegang teguh pada kode etik. Nilai etika dan pilihan moral pada Tempo sesuai dengan visi Koran Tempo.Redaksi koran Tempo sebagai Perusahaan yang produknya informasi , diharapkan selalu menjaga obyektivitas dalam menyampaikan pemberitaan dengan memperbanyak sumber berita dan terus menerus meningkatkan apresiasi terhadap ide-ide baru, bahasa, dan tampilan visual yang baik sehinggs dapat menampilkan sebuah informasi yang bermutu tinggi dan layak dikonsumsi masyarakat

    A new approach for the analysis of bacterial microarray-based Comparative Genomic Hybridization: insights from an empirical study

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    BACKGROUND: Microarray-based Comparative Genomic Hybridization (M-CGH) has been used to characterize the extensive intraspecies genetic diversity found in bacteria at the whole-genome level. Although conventional microarray analytical procedures have proved adequate in handling M-CGH data, data interpretation using these methods is based on a continuous character model in which gene divergence and gene absence form a spectrum of decreasing gene conservation levels. However, whereas gene divergence may yet be accompanied by retention in gene function, gene absence invariably leads to loss of function. This distinction, if ignored, leads to a loss in the information to be gained from M-CGH data. We present here results from experiments in which two genome-sequenced strains of C. jejuni were compared against each other using M-CGH. Because the gene content of both strains was known a priori, we were able to closely examine the effects of sequence divergence and gene absence on M-CGH data in order to define analytical parameters for M-CGH data interpretation. This would facilitate the examination of the relative effects of sequence divergence or gene absence in comparative genomics analyses of multiple strains of any species for which genome sequence data and a DNA microarray are available. RESULTS: As a first step towards improving the analysis of M-CGH data, we estimated the degree of experimental error in a series of experiments in which identical samples were compared against each other by M-CGH. This variance estimate was used to validate a Log Ratio-based methodology for identification of outliers in M-CGH data. We compared two genome strains by M-CGH to examine the effect of probe/target identity on the Log Ratios of signal intensities using prior knowledge of gene divergence and gene absence to establish Log Ratio thresholds for the identification of absent and conserved genes. CONCLUSION: The results from this empirical study validate the Log Ratio thresholds that have been used in other studies to establish gene divergence/absence. Moreover, the analytical framework presented here enhances the information content derived from M-CGH data by shifting the focus from divergent/absent gene detection to accurate detection of conserved and absent genes. This approach closely aligns the technical limitations of M-CGH analysis with practical limitations on the biological interpretation of comparative genomics data

    A simple method for estimating larval supply in reef fishes and a preliminary test of population limitation by larval delivery in the kelp bass \u3cem\u3eParalabrax clathratus\u3c/em\u3e

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    This paper describes a method for estimating larval supply of a temperate reef fish, the kelp bass Paralabrax clathratus, that is simple, inexpensive, requires relatively low effort, and integrates larval supply over time. Using this method, we sampled larval supply concurrently at 4 sites spread over about 35 km for nearly an entire settlement season. With these data and visual estimates of recruitment (the density of young-of-the-year after the end of the settlement season), we tested the hypothesis that spatial patterns in recruitment were set by larval supply. This hypothesis was rejected: kelp bass recruitment to the 4 sites was not related to patterns of larval supply. Furthermore, in contrast to the findings of an earlier study, recruitment was not related to the density of the macroalga Macrocystis pyrifera. Recruitment was, however, strongly correlated with the density of 1 yr old kelp bass, suggesting that spatial patterns of recruitment were consistent between the 2 cohorts. Recruitment, however, was not correlated with the density of bass 2+ yr old. We also measured larval supply in a second year and found that spatial patterns of supply were strongly correlated between years at a relatively small scale of 10s to 100s m, but not at a larger scale of several km. This finding suggests that some deterministic process (or set of processes) sets spatial patterns of larval supply at small, but not large scales. At large scales, consistent patterns of recruitment between 2 cohorts in the face of variable larval supply suggest that deterministic, postsettlement processes may generate predictable patterns of recruitment even when the supply of larvae is variable. In addition to demonstrating that spatial patterns in the abundance of demersal fish are not always well predicted by larval supply, this study introduces a technique that may facilitate more thorough exploration of the role of larval supply in determining the dynamics of populations of reef fishes

    Microarray-based comparative genomic profiling of reference strains and selected Canadian field isolates of Actinobacillus pleuropneumoniae

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    <p>Abstract</p> <p>Background</p> <p><it>Actinobacillus pleuropneumoniae</it>, the causative agent of porcine pleuropneumonia, is a highly contagious respiratory pathogen that causes severe losses to the swine industry worldwide. Current commercially-available vaccines are of limited value because they do not induce cross-serovar immunity and do not prevent development of the carrier state. Microarray-based comparative genomic hybridizations (M-CGH) were used to estimate whole genomic diversity of representative <it>Actinobacillus pleuropneumoniae </it>strains. Our goal was to identify conserved genes, especially those predicted to encode outer membrane proteins and lipoproteins because of their potential for the development of more effective vaccines.</p> <p>Results</p> <p>Using hierarchical clustering, our M-CGH results showed that the majority of the genes in the genome of the serovar 5 <it>A. pleuropneumoniae </it>L20 strain were conserved in the reference strains of all 15 serovars and in representative field isolates. Fifty-eight conserved genes predicted to encode for outer membrane proteins or lipoproteins were identified. As well, there were several clusters of diverged or absent genes including those associated with capsule biosynthesis, toxin production as well as genes typically associated with mobile elements.</p> <p>Conclusion</p> <p>Although <it>A. pleuropneumoniae </it>strains are essentially clonal, M-CGH analysis of the reference strains of the fifteen serovars and representative field isolates revealed several classes of genes that were divergent or absent. Not surprisingly, these included genes associated with capsule biosynthesis as the capsule is associated with sero-specificity. Several of the conserved genes were identified as candidates for vaccine development, and we conclude that M-CGH is a valuable tool for reverse vaccinology.</p

    Genome-wide expression analyses of Campylobacter jejuni NCTC11168 reveals coordinate regulation of motility and virulence by flhA.

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    We examined two variants of the genome-sequenced strain, Campylobacter jejuni NCTC11168, which show marked differences in their virulence properties including colonization of poultry, invasion of Caco-2 cells, and motility. Transcript profiles obtained from whole genome DNA microarrays and proteome analyses demonstrated that these differences are reflected in late flagellar structural components and in virulence factors including those involved in flagellar glycosylation and cytolethal distending toxin production. We identified putative sigma(28) and sigma(54) promoters for many of the affected genes and found that greater differences in expression were observed for sigma(28)-controlled genes. Inactivation of the gene encoding sigma(28), fliA, resulted in an unexpected increase in transcripts with sigma(54) promoters, as well as decreased transcription of sigma(28)-regulated genes. This was unlike the transcription profile observed for the attenuated C. jejuni variant, suggesting that the reduced virulence of this organism was not entirely due to impaired function of sigma(28). However, inactivation of flhA, an important component of the flagellar export apparatus, resulted in expression patterns similar to that of the attenuated variant. These findings indicate that the flagellar regulatory system plays an important role in campylobacter pathogenesis and that flhA is a key element involved in the coordinate regulation of late flagellar genes and of virulence factors in C. jejuni

    Vascularized tissue‐engineered chambers promote survival and function of transplanted islets and improve glycemic control

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154402/1/fsb2fj054879fje.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154402/2/fsb2fj054879fje-sup-0001.pd
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