Advanced expander test bed program

The Advanced Expander Test Bed (AETB) is a key element in NASA's Space Chemical Engine Technology Program for development and demonstration of expander cycle oxygen/hydrogen engine and advanced component technologies applicable to space engines as well as launch vehicle upper stage engines. The AETB will be used to validate the high-pressure expander cycle concept, investigate system interactions, and conduct investigations of advanced mission focused components and new health monitoring techniques in an engine system environment. The split expander cycle AETB will operate at combustion chamber pressures up to 1200 psia with propellant flow rates equivalent to 20,000 lbf vacuum thrust. Contract work began 27 Apr. 1990. During 1992, a major milestone was achieved with the review of the final design of the oxidizer turbopump in Sep. 1992

Cool early Albian climates; new data from Argentina

Previous studies on the stable isotope geochemistry of dimitobelid belemnites from Antarctica and Australia indicated cool climatic conditions during the early Albian in the shelf seas around the Gondwanan margin. In this paper new analyses from diagenetically unaltered specimens of Dimitobelus cf. stimulus from early Albian deposits of the Rio Mayer Formation of Lago San Martin, southern Argentina are presented. Oxygen isotope values for diagenetically least altered samples give values ranging between d18O C0.07 and C0.96 vPDB, which equate to a mean palaeotemperature of 9.5 (C (assuming dw of 1.2& SMOW). These data are consistent with a model of cool early Albian shelf seas in the Southern Hemisphere.Facultad de Ciencias Naturales y Muse

Cool early Albian climates; new data from Argentina

Previous studies on the stable isotope geochemistry of dimitobelid belemnites from Antarctica and Australia indicated cool climatic conditions during the early Albian in the shelf seas around the Gondwanan margin. In this paper new analyses from diagenetically unaltered specimens of Dimitobelus cf. stimulus from early Albian deposits of the Rio Mayer Formation of Lago San Martin, southern Argentina are presented. Oxygen isotope values for diagenetically least altered samples give values ranging between d18O C0.07 and C0.96 vPDB, which equate to a mean palaeotemperature of 9.5 (C (assuming dw of 1.2& SMOW). These data are consistent with a model of cool early Albian shelf seas in the Southern Hemisphere.Facultad de Ciencias Naturales y Muse

Cool early Albian climates; new data from Argentina

Previous studies on the stable isotope geochemistry of dimitobelid belemnites from Antarctica and Australia indicated cool climatic conditions during the early Albian in the shelf seas around the Gondwanan margin. In this paper new analyses from diagenetically unaltered specimens of Dimitobelus cf. stimulus from early Albian deposits of the Rio Mayer Formation of Lago San Martin, southern Argentina are presented. Oxygen isotope values for diagenetically least altered samples give values ranging between d18O C0.07 and C0.96 vPDB, which equate to a mean palaeotemperature of 9.5 (C (assuming dw of 1.2& SMOW). These data are consistent with a model of cool early Albian shelf seas in the Southern Hemisphere.Facultad de Ciencias Naturales y Muse

Statistical analysis of correlations and intermittency of a turbulent rotating column in a magnetoplasma device

12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France)A detailed statistical analysis of density fluctuations in the cylindrical non-fusion device "Mistral" is performed. The experimental set-up is implemented in order to reach turbulent behavior in the rotating plasma column. Two different turbulent regimes are obtained corresponding to two selected sets of values for the anode potential and the biasing of the collecting plate. The first regime displays a slowly-rotating column characterized by the presence of a shear layer separating the plasma bulk from the scrape-off layer (SOL), the latter showing a strong intermittent behavior. The second regime corresponds to a weakly-rotating column in which coherence is lost in the plasma bulk and a standard diffusive process takes place in the SOL. These findings are supported by the calculation of the Hurst exponent of the turbulent signals using Wavelet-analysis techniques

Etiological diagnosis, prognostic significance and role of electrophysiological study in patients with Brugada ECG and syncope.

BACKGROUND: Syncope is considered a risk factor for life-threatening arrhythmias in Brugada patients. Distinguishing a benign syncope from one due to ventricular arrhythmias is often difficult, unless an ECG is recorded during the episode. Aim of the study was to analyze the characteristics of syncopal episodes in a large population of Brugada patients and evaluate the role of electrophysiological study (EPS) and the prognosis in the different subgroups. METHODS AND RESULTS: One hundred ninety-five Brugada patients with history of syncope were considered. Syncope were classified as neurally mediated (group 1, 61%) or unexplained (group 2, 39%) on the basis of personal and family history, clinical features, triggers, situations, associated signs, concomitant therapy. Most patients underwent EPS; they received ICD or implantable loop-recorder on the basis of the result of investigations and physician's judgment. At 62±45months of mean follow-up, group 1 showed a significantly lower incidence of arrhythmic events (2%) as compared to group 2 (9%, p<0.001). Group 2 patients with positive EPS showed the highest risk of arrhythmic events (27%). No ventricular events occurred in subjects with negative EPS. CONCLUSION: Etiological definition of syncope in Brugada patients is important, as it allows identifying two groups with different outcome. Patients with unexplained syncope and ventricular fibrillation induced at EPS have the highest risk of arrhythmic events. Patients presenting with neurally mediated syncope showed a prognosis similar to that of the asymptomatic and the role of EPS in this group is unproven

Coordinating Pluggable Transceiver Control in SONiC-based Disaggregated Packet-Optical Networks

Effective control of pluggable transceivers in SONiC-based packet-optical nodes is demonstrated. A workflow for multi-layer recovery upon soft failure detection is validated, showing no traffic disruption and fast node-driven coordination between packet and optical operations

Charge-transfer interactions stabilize g-quadruplex-forming thrombin binding aptamers and can improve their anticoagulant activity

In the search for optimized thrombin binding aptamers (TBAs), we herein describe the synthesis of a library of TBA analogues obtained by end-functionalization with the electron-rich 1,5-dialkoxy naphthalene (DAN) and the electron-deficient 1,8,4,5-naphthalenetetra-carboxylic diimide (NDI) moieties. Indeed, when these G-rich oligonucleotides were folded into the peculiar TBA G-quadruplex (G4) structure, effective donor–acceptor charge transfer interactions between the DAN and NDI residues attached to the extremities of the sequence were induced, providing pseudo-cyclic structures. Alternatively, insertion of NDI groups at both extremities produced TBA analogues stabilized by π–π stacking interactions. All the doubly-modified TBAs were characterized by different biophysical techniques and compared with the analogues carrying only the DAN or NDI residue and unmodified TBA. These modified TBAs exhibited higher nuclease resistance, and their G4 structures were markedly stabilized, as evidenced by increased Tm values compared to TBA. These favorable properties were also associated with improved anticoagulant activity for one DAN/NDI-modified TBA, and for one NDI/NDI-modified TBA. Our results indicated that TBA pseudo-cyclic structuring by ad hoc designed end-functionalization represents an efficient approach to improve the aptamer features, while pre-organizing and stabilizing the G4 structure but allowing sufficient flexibility to the aptamer folding, which is necessary for optimal thrombin recognition