1,622 research outputs found

    Nucleotides and organophosphates of cardiac, fast, and slow muscles of chick during development

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    Nucleotides like ATP, ADP, AMP and organophosphate, a compd. like creatine phosphate, creatine, and creatinine were estd. in the cardiac, slow anterior latissimus dorsi (ALD) and fast posterior latissimus dorsi (PLD) muscles of the prenatal chick. A decrease in the ATP level and an increase in the ADP​/ATP ratio was obsd. with the advance in development in all muscle types. The increase in ADP level with an increase in development was noted with a complementary increase in the activity of ATP creatine transphosphorylase in all types. A gradual increase in creatine phosphate and a decrease in free phosphate in all the muscle types was recorded. The utilization of ATP as indicated by phosphate potential was suggested to be existing during development by way of increased transphosphorylation. The heart and ALD muscles exhibited similar trends in ATP utilization up to the 16th day. The Ca2+ and Mg2+ activated myofibrillar activity exhibited a decrease with ref. to development. The studies on ocular shortening of glycerinated fibers revealed that the contractility of the fibers progressively increased with development. The ALD fibers are bound to Ca2+ more than that of PLD and heart. The sensitivity of Ca2+ to the fibers changes with development as the PLD fibers become more sensitive:heart fibers lose their sensitivity; and ALD fibers have a mixed nature with ref. to Ca2+ sensitivity

    Design and Analysis of a Multi-Agent E-Learning System Using Prometheus Design Tool

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    Agent unified modeling languages (AUML) are agent-oriented approaches that supports the specification, design, visualization and documentation of an agent-based system. This paper presents the use of Prometheus AUML approach for the modeling of a Pre-assessment System of five interactive agents. The Pre-assessment System, as previously reported, is a multi-agent based e-learning system that is developed to support the assessment of prior learning skills in students so as to classify their skills and make recommendation for their learning. This paper discusses the detailed design approach of the system in a step-by-step manner; and domain knowledge abstraction and organization in the system. In addition, the analysis of the data collated and models of prediction for future pre-assessment results are also presented.Comment: 17 figures, 3 table

    Scheduling aircraft landings - the static case

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    This is the publisher version of the article, obtained from the link below.In this paper, we consider the problem of scheduling aircraft (plane) landings at an airport. This problem is one of deciding a landing time for each plane such that each plane lands within a predetermined time window and that separation criteria between the landing of a plane and the landing of all successive planes are respected. We present a mixed-integer zero–one formulation of the problem for the single runway case and extend it to the multiple runway case. We strengthen the linear programming relaxations of these formulations by introducing additional constraints. Throughout, we discuss how our formulations can be used to model a number of issues (choice of objective function, precedence restrictions, restricting the number of landings in a given time period, runway workload balancing) commonly encountered in practice. The problem is solved optimally using linear programming-based tree search. We also present an effective heuristic algorithm for the problem. Computational results for both the heuristic and the optimal algorithm are presented for a number of test problems involving up to 50 planes and four runways.J.E.Beasley. would like to acknowledge the financial support of the Commonwealth Scientific and Industrial Research Organization, Australia

    Topological Transitions in Metamaterials

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    The ideas of mathematical topology play an important role in many aspects of modern physics - from phase transitions to field theory to nonlinear dynamics (Nakahara M (2003) in Geometry, Topology and Physics, ed Brewer DF (IOP Publishing Ltd, Bristol and Philadelphia), Monastryskiy M (1987) in Riemann Topology and Physics, (Birkhauser Verlag AG)). An important example of this is the Lifshitz transition (Lifshitz IM (1960) Anomalies of electron characteristics of a metal in the high-pressure region, Sov Phys JETP 11: 1130-1135), where the transformation of the Fermi surface of a metal from a closed to an open geometry (due to e.g. external pressure) leads to a dramatic effect on the electron magneto-transport (Kosevich AM (2004) Topology and solid-state physics. Low Temp Phys 30: 97-118). Here, we present the optical equivalent of the Lifshitz transition in strongly anisotropic metamaterials. When one of the components of the dielectric permittivity tensor of such a composite changes sign, the corresponding iso-frequency surface transforms from an ellipsoid to a hyperboloid. Since the photonic density of states can be related to the volume enclosed by the iso-frequency surface, such a topological transition in a metamaterial leads to a dramatic change in the photonic density of states, with a resulting effect on every single physical parameter related to the metamaterial - from thermodynamic quantities such as its equilibrium electromagnetic energy to the nonlinear optical response to quantum-electrodynamic effects such as spontaneous emission. In the present paper, we demonstrate the modification of spontaneous light emission from quantum dots placed near the surface of the metamaterial undergoing the topological Lifshitz transition, and present the theoretical description of the effect

    Some remarks on the hyperelliptic moduli of genus 3

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    In 1967, Shioda \cite{Shi1} determined the ring of invariants of binary octavics and their syzygies using the symbolic method. We discover that the syzygies determined in \cite{Shi1} are incorrect. In this paper, we compute the correct equations among the invariants of the binary octavics and give necessary and sufficient conditions for two genus 3 hyperelliptic curves to be isomorphic over an algebraically closed field kk, chk2,3,5,7\ch k \neq 2, 3, 5, 7. For the first time, an explicit equation of the hyperelliptic moduli for genus 3 is computed in terms of absolute invariants.Comment: arXiv admin note: text overlap with arXiv:1209.044

    Acetylcholinesterase activity in the embryonic muscles of chick

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    Acetylcholinesterase activity in the exts. of fast (posterior latissimus dorsi; PLD)​, slow (anterior latissimus dorsi; ALD)​, and cardiac muscles of embryonic chick was estd. by the titrimetric method. The activity in the fast PLD gradually increased up to 16th day of development and gradually decreased afterwards. In the slow ALD there was an increase in activity up to 16th day, but later on the activity became steady. The heart maintained a steady level from the 8th day onwards. The decay of activity in PLD and maintenance of steady level in ALD after the 16th day and in heart from the 8th day of incubation are discussed with ref. to the establishment of muscle-​nerve interaction

    Hospital Change to Mixed Lipid Emulsion From Soybean Oil-Based Lipid Emulsion for Parenteral Nutrition in Hospitalized and Critically Ill Adults Improves Outcomes: A Pre-Post-Comparative Study

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    INTRODUCTION: Early data suggest use of a mixed lipid emulsion (LE) with a soybean oil reduction strategy in parenteral nutrition (PN) may improve clinical outcomes. Duke University Hospital made a full switch to a Soybean oil/MCT/Olive/Fish Oil lipid (4-OLE) from pure soybean oil-based LE (Intralipid, Baxter Inc) in May 2017. Since 4-OLE has limited evidence related to its effects on clinical outcome parameters in US hospitals, evidence for clinical benefits of switching to 4-OLE is needed. Therefore, we examined the clinical utility of a hospital-wide switch to 4-OLE and its effect on patient outcomes. METHODS: We conducted a single-center retrospective cohort study among adult patients (\u3e 18 years) requiring PN from 2016 to 2019. Our primary exposure was treatment period (1-year pre-4-OLE switch versus 2-year post). We used multivariable regression models to examine our primary outcomes, the association of treatment period with hospital length of stay (LOS), and secondary outcomes liver function, infections, and ICU LOS. Analyses were stratified into critically ill and entire adult cohort. RESULTS: We identified 1200 adults hospitalized patients. 28% of PN patients (n = 341) were treated pre-4-OLE switch and 72% post-4-OLE (n = 859). In the adult cohort, 4-OLE was associated with shorter hospital LOS (IRR 0.97, 95% CI 0.95-0.99, p = 0.039). The ICU cohort included 447 subjects, of which 25% (n = 110) were treated pre-4-OLE switch and 75% (n = 337) were post-switch. ICU patients receiving 4-OLE were associated with shorter hospital LOS (IRR 0.91, 95% CI 0.87-0.93, p \u3c 0.0001), as well as a shorter ICU LOS (IRR 0.90, 95% CI 0.82-0.99, p = 0.036). 4-OLE ICU patients also had a significantly lower delta total bilirubin (- 1.6, 95% CI - 2.8 to - 0.2, p = 0.021) and reduced urinary tract infection (UTI) rates (OR 0.50, 95% CI 0.26-0.96, p = 0.038). There were no associations in AST, ALT, or total bilirubin in ICU and all adult patients. CONCLUSION: 4-OLE was successfully implemented and reduced soybean oil LE exposure in a large academic hospital setting. The introduction of 4-OLE was associated with reduced LOS, UTI rates, and mitigated hepatic dysfunction in critically ill patients. Overall, these findings prove a switch to a soybean oil-LE sparing strategy using 4-OLE is feasible and safe and is associated with improved clinical outcomes in adult PN patients
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