196,680 research outputs found
CVR recordings of explosions and structural failure decompressions
No full textRapid identification of the cause of failure is a high priority in the immediate aftermath
of a major civil aircraft accident. Attention is often focused on the two recorders, the
Cockpit Voice Recorder (CVR) and flight data recorder. In the event of sudden,
catastrophic loss of an aircraft through explosions or structural failure decompressions,
the recordings are seen as even more important. Yet these recorders are not designed to
record such events with great fidelity and the ability of accident investigators to
interpret such recordings has been severely tested in several major accidents in the past
thirty years; comparisons between accident recordings have not been able to produce
conclusive results. This paper reports on a programme investigating CVR recordings of
explosions and rapid decompressions on a variety of aircraft from trials in several
countries. In particular we show that CVR recordings are generally unable to
discriminate between explosions and structural failure decompressions and we explain
why this is so. We shall also put forward practical suggestions for systems that may be
able to record these events with greater fidelity and which would provide investigators
in the future with tools to locate the seat of the failure
General-dyne unravelling of a thermal master equation
No full textWe analyze the unravelling of the quantum optical master equation at finite temperature due to direct, continuous, general-dyne detection of the environment. We first express the general-dyne Positive Operator Valued Measure (POVM) in terms of the eigenstates of a non-Hermitian operator associated to the general-dyne measurement. Then we derive the stochastic master equation obtained by considering the interaction between the system and a reservoir at thermal equilibrium, which is measured according to the POVM previously determined. Finally, we present a feasible measurement scheme, which reproduces general-dyne detection for any value of the parameter characterizing the stochastic master equation
Some properties of the alkaline proteinase from Aspergillus melleus.
No full textSeaprose is a semi-alkaline proteinase produced by Aspergillus melleus. The aim of our study was to further characterize the properties of this enzyme, particularly looking at its interaction with alpha 1-proteinase inhibitor, the major human plasma proteinase inhibitor. We studied the cleavage of three synthetic peptide substrates induced by seaprose and the inhibitory profile of the enzyme by means of a panel of inhibitors, including alpha 1-proteinase inhibitor. The interaction between seaprose and alpha 1-proteinase inhibitor was also studied with SDS-PAGE. Finally, the elastolytic activity of seaprose was checked by means of bovine elastin solubilization. We found that seaprose cleaves preferentially the substrate containing a Phe residue in the P1 position. The inhibitory profile showed that seaprose is a serine-proteinase that cannot be inhibited by alpha 1-proteinase inhibitor. The SDS-PAGE revealed that alpha 1-proteinase inhibitor, after incubation with seaprose, underwent a limited proteolysis. Finally, seaprose 10(-2) M and 10(-3) M was able to solubilize bovine elastin. We conclude that seaprose is a serine-proteinase able to inactivate human alpha 1-proteinase inhibitor with limited proteolysis at (or near) the active site and that it has mild elastinolytic capacity
Type I collagen CNBr peptides: species and behavior in solution
No full textThe properties of type I collagen CNBr peptides in solution were studied to investigate the molecular species formed, their conformation, and factors influencing equilibria between peptide species. Peptides formed homologous trimers, even though the native parent protein is heterotrimeric, [alpha 1(I)]2 alpha 2-(I). Their triple-helical content was found to be high (> 75% for most peptides). Full helical content was not reached mainly because of the presence of monomer species; chain misalignment, if present, and trimer unraveling at terminal ends appeared to play a minor role in reducing helicity. Circular dichroism spectra and resistance to trypsin digestion at 4 and 20 degrees C demonstrated that the conformation of trimers was very similar to the collagen triple-helical conformation. Rotary shadowing of peptide alpha 1(I) CB7 supported this finding. Analytical gel filtration in nondenaturing conditions showed that the trimers of some peptides have the ability to autoaggregate. In the case of peptides alpha 1(I) CB8 and alpha 2(I) CB4, most of the intermolecular interactions between trimeric molecules were disrupted by 0.5 M NaCl, demonstrating that their ionic character is important. Changes in ionic strength also altered the hydrodynamic size of single- and triple-stranded molecules. The different molecular species are in equilibrium. The kinetics of the conversion of trimer to monomer species was determined in a time course experiment using trypsin digestion and found to be a relatively slow process (trimer half-life is a few days at 4 degrees C, about one order of magnitude lower at 20 degrees C) with an activation energy of roughly 4-9 kcal/mol. The circular dichroism profile at increasing temperatures showed that the melting temperature for triple-helical peptides is about 6-10 degrees C lower than that of the parent native type I collagen. The folding of peptides is a spontaneous process (exothermic but with unfavourable entropy change), and the triple-helical conformation originates solely as the result of the collagen sequence because it forms from heat-denatured samples
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
Complete resolution of imidodipeptide mixtures in urine of prolidase-deficient patients using micellar electrokinetic chromatography.
No full textThe use of capillary zone electrophoresis as an efficient method for the identification of urinary imidodipeptides of prolidase-deficient patients has already been reported. However, owing to the complexity of the components excreted, the resolution of electrophoretic patterns obtained was poor. Here we examine the use of micellar electrokinetic chromatography to enhance peak resolution in order to obtain better insight into the electropherograms of patients' urine. The usefulness of sodium dodecyl sulphate as surfactant is reported: refined electropherograms were achieved using 35 mM sodium borate, pH 8.3 containing 65 mM sodium dodecyl sulphate. Almost all peaks were baseline separated, collected and sequenced. This allowed us to define the exact imidodipeptide composition of patients' urine. The possibility of identifying and thus quantifying each single peak means that comparison of urinary imidodipeptide excretion patterns from different patients can be made and the hypothesis that peptide patterns can be correlated with differing clinical severity can be investigated
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