1,137 research outputs found

    Development of an interface for an ultrareliable fault-tolerant control system and an electronic servo-control unit

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    The NASA Ames Research Center sponsors a research program for the investigation of Intelligent Flight Control Actuation systems. The use of artificial intelligence techniques in conjunction with algorithmic techniques for autonomous, decentralized fault management of flight-control actuation systems is explored under this program. The design, development, and operation of the interface for laboratory investigation of this program is documented. The interface, architecturally based on the Intel 8751 microcontroller, is an interrupt-driven system designed to receive a digital message from an ultrareliable fault-tolerant control system (UFTCS). The interface links the UFTCS to an electronic servo-control unit, which controls a set of hydraulic actuators. It was necessary to build a UFTCS emulator (also based on the Intel 8751) to provide signal sources for testing the equipment

    Steer stress response as affected by genotype and transportation

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    Bovine cytochrome P450 3A28 is responsible for metabolizing ergot alkaloids that cattle ingest when feeding on endophyte-infested tall fescue grass. The objective of this research was to determine associations among genotype, transportation, and stress responses. Angus crossbred steers (n = 47) were genotyped (CC, CG, or GG) for a single-nucleotide polymorphism (C994G) in cytochrome P450 3A28. Genotypes were determined by polymerase chain reaction (PCR) amplification followed by restriction enzyme (Alu1) digestion. Steers were backgrounded on a mixedcultivar tall fescue pasture. Following the stocker phase, steers were transported to the feedlot for finishing. Stress responses were determined 27 h prior to, and 6 and 20 h after transport. Plasma concentrations of prolactin and cortisol, and white blood cell expression of prolactin, cytochrome P450, tumor necrosis factor-alpha, and short form prolactin receptor were our indicators of stress. Both time and genotypic effects were determined. Time (P \u3c 0.05) relative to transportation was associated with expression of all four genes tested. In addition, plasma concentrations of cortisol and prolactin, as well as their ratio were affected (P \u3c 0.05) by time. In contrast, neither genotype nor the interaction between genotype and time affected (P \u3e 0.1) our stress indicators. In previous studies, C994G genotype has been associated with cattle productivity; however, those effects were not observed in this study

    Implications for CP asymmetries of improved data on BK0π0B \to K^0 \pi^0

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    The decay B0K0π0B^0 \to K^0 \pi^0, dominated by a bsb \to s penguin amplitude, holds the potential for exhibiting new physics in this amplitude. In the pure QCD penguin limit one expects \ckp = 0 and \skp = \sin 2 \beta for the coefficients of cosΔmt\cos \Delta m t and sinΔmt\sin \Delta m t in the time-dependent CP asymmetry. Small non-penguin contributions lead to corrections to these expressions which are calculated in terms of isospin-related BKπB\to K\pi rates and asymmetries, using information about strong phases from experiment. We study the prospects for incisive tests of the Standard Model through examination of these corrections. We update a prediction \ckp=0.15\pm 0.04, pointing out the sensitivity of a prediction \skp\approx 1 to the measured branching ratio for B0K0π0B^0\to K^0\pi^0 and to other observables.Comment: Note added, to be published in Physics Letters

    Suppression of flavor symmetry breaking in B decay sum rules

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    While flavor symmetries are useful for studying hadronic B decays, symmetry relations for amplitudes and decay rates are usually violated by first order symmetry breaking corrections. We point out two cases in which first order symmetry breaking is suppressed by a small ratio of amplitudes: (1) An isospin sum rule for four BKπB\to K\pi decays, where isospin breaking is shown to be negligible. (2) An SU(3) sum rule for pairs of BKπB\to K\pi and BKη8B\to K\eta_8, generalized to pairs of BKπ,BKηB\to K\pi, B\to K\eta and BKηB\to K\eta'.Comment: 11 pages, small corrections, one reference added, submitted to Physics Letters

    Antibodies to Nipah-Like Virus in Bats (Pteropus lylei), Cambodia

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    Serum specimens from fruit bats were obtained at restaurants in Cambodia. We detected antibodies cross-reactive to Nipah virus by enzyme immunoassay in 11 (11.5%) of 96 Lyle’s flying foxes (Pteropus lylei). Our study suggests that viruses closely related to Nipah or Hendra viruses are more widespread in Southeast Asia than previously documented

    Pre-Training Muscle Characteristics of Subjects Who Are Obese Determine How Well Exercise Training Will Improve Their Insulin Responsiveness

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    Pre-training muscle characteristics of subjects who are obese determine how well exercise training will improve their insulin responsiveness. J Strength Cond Res 31(3): 798–808, 2017—Only half of prediabetic subjects who are obese who underwent exercise training without weight loss increased their insulin responsiveness. We hypothesized that those who improved their insulin responsiveness might have pretraining characteristics favoring a positive response to exercise training. Thirty nondiabetic subjects who were obese volunteered for 8 weeks of either strength training or endurance training. During training, subjects increased their caloric intake to prevent weight loss. Insulin responsiveness by euglycemic clamps and muscle fiber composition, and expression of muscle key biochemical pathways were quantified. Positive responders initially had 52% higher intermediate muscle fibers (fiber type IIa) with 27% lower slow-twitch fibers (type I) and 23% lower expression of muscle insulin receptors. Whether after weight training or stationary bike training, positive responders\u27 fiber type shifted away from type I and type IIa fibers to an increased proportion of type IIx fibers (fast twitch). Muscle insulin receptor expression and glucose transporter type 4 (GLUT4) expression increased in all trained subjects, but these moderate changes did not consistently translate to improvement in whole-body insulin responsiveness. Exercise training of previously sedentary subjects who are obese can result in muscle remodeling and increased expression of key elements of the insulin pathway, but in the absence of weight loss, insulin sensitivity improvement was modest and limited to about half of the participants. Our data suggest rather than responders being more fit, they may have been less fit, only catching up to the other half of subjects who are obese whose insulin responsiveness did not increase beyond their pretraining baseline

    A phase I study of intraperitoneal nanoparticulate paclitaxel (Nanotax®) in patients with peritoneal malignancies

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    PURPOSE: This multicenter, open-label, dose-escalating, phase I study evaluated the safety, tolerability, pharmacokinetics and preliminary tumor response of a nanoparticulate formulation of paclitaxel (Nanotax®) administered intraperitoneally for multiple treatment cycles in patients with solid tumors predominantly confined to the peritoneal cavity for whom no other curative systemic therapy treatment options were available. METHODS: Twenty-one patients with peritoneal malignancies received Nanotax® in a modified dose-escalation approach utilizing an accelerated titration method. All patients enrolled had previously received chemotherapeutics and undergone surgical procedures, including 33 % with optimal debulking. Six doses (50–275 mg/m2) of Cremophor-free Nanotax® were administered intraperitoneally for one to six cycles (every 28 days). RESULTS: Intraperitoneal (IP) administration of Nanotax® did not lead to increases in toxicity over that typically associated with intravenous (IV) paclitaxel. No patient reported ≥Grade 2 neutropenia and/or ≥Grade 3 neurologic toxicities. Grade 3 thrombocytopenia unlikely related to study medication occurred in one patient. The peritoneal concentration–time profile of paclitaxel rose during the 2 days after dosing to peritoneal fluid concentrations 450–2900 times greater than peak plasma drug concentrations and remained elevated through the entire dose cycle. Best response assessments were made in 16/21 patients: Four patients were assessed as stable or had no response and twelve patients had increasing disease. Five of 21 patients with advanced cancers survived longer than 400 days after initiation of Nanotax® IP treatment. CONCLUSIONS: Compared to IV paclitaxel administration, Cremophor-free IP administration of Nanotax® provides higher and prolonged peritoneal paclitaxel levels with minimal systemic exposure and reduced toxicity
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