2,867 research outputs found

    Mutation of Directed Graphs -- Corresponding Regular Expressions and Complexity of Their Generation

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    Directed graphs (DG), interpreted as state transition diagrams, are traditionally used to represent finite-state automata (FSA). In the context of formal languages, both FSA and regular expressions (RE) are equivalent in that they accept and generate, respectively, type-3 (regular) languages. Based on our previous work, this paper analyzes effects of graph manipulations on corresponding RE. In this present, starting stage we assume that the DG under consideration contains no cycles. Graph manipulation is performed by deleting or inserting of nodes or arcs. Combined and/or multiple application of these basic operators enable a great variety of transformations of DG (and corresponding RE) that can be seen as mutants of the original DG (and corresponding RE). DG are popular for modeling complex systems; however they easily become intractable if the system under consideration is complex and/or large. In such situations, we propose to switch to corresponding RE in order to benefit from their compact format for modeling and algebraic operations for analysis. The results of the study are of great potential interest to mutation testing

    Simulating Gyrokinetic Microinstabilities in Stellarator Geometry with GS2

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    The nonlinear gyrokinetic code GS2 has been extended to treat non-axisymmetric stellarator geometry. Electromagnetic perturbations and multiple trapped particle regions are allowed. Here, linear, collisionless, electrostatic simulations of the quasi-axisymmetric, three-field period National Compact Stellarator Experiment (NCSX) design QAS3-C82 have been successfully benchmarked against the eigenvalue code FULL. Quantitatively, the linear stability calculations of GS2 and FULL agree to within ~10%.Comment: Submitted to Physics of Plasmas. 9 pages, 14 figure

    Early mapping of industrial tomato in Central and Southern Italy with Sentinel 2, aerial and RapidEye additional data

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    Timely crop information, i.e. well before harvesting time and at first stages of crop development, can benefit farmers and producer organizations. The current case study documents the procedure to deliver early data on planted tomato to users, showing the potential of Sentinel 2 to map tomato at the very beginning of the crop season, which is a challenging task. Using satellite data, integrated with ground and aerial data, an initial estimate of area planted with tomato and early tomato maps were generated in seven main production areas in Italy. Estimates of the amount of area planted with tomato provided similar results either when derived from field surveys or from remote sensing-based classification. Tomato early maps showed a producer accuracy > 80% in seven cases out of nine, and a user accuracy > 80% in five cases out of nine, with differences attributed to the varying agricultural characteristics and environmental heterogeneity of the study areas. The additional use of aerial data improved producer accuracy moderately. The ability to identify abrupt growth changes, such as those caused by natural hazards, was also analysed: Sentinel 2 detected significant changes in tomato growth between a hailstorm-affected area and a control area. The study suggests that Sentinel 2, with enhanced spectral capabilities and open data policy, represents very valuable data, allowing crop monitoring at an early development stage

    Behaviour of adenylic and pyridinic compounds in gingival tissue after a short-term exposure to air

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    Biochemical variations of adenine and pyridine compounds in human gingival grafts during the period between excision and implantation have been studied. These groups of compounds are considered as «indicators» of the metabolic and energetic status of the living cells. Adenylic compounds such as ATP, ADP and AMP are involved in numerous metabolic processes as «modulators» of allosteric enzymes.NAD+ and NADP+ are involved in the carbohydrate metabolism as co-factors of many reactions of oxydoreduction. The exposure to air of the gingival tissue induces modifications in the energy state of the cells as well as in the ox-reox system. No variation is detectable in the intermediates of the pyridine compounds cycle.Dans des gencives humaines prélevées pour des greffes, ont été étudiées, à certains intervalles de temps entre le prélèvement et la greffe, les variations biochimiques des composés adényliques et pyridiniques, qui sont les «indicateurs» des conditions énergétiques et métaboliques du tissu. Des composés comme l’ATP, l’ADP et l’AMP participent à de nombreux processus métaboliques comme «modulateurs» des enzymes allostériques. NAD+ et NADP + participent au métabolisme des carbohydrates comme co-facteurs de nombreuses réactions d’oxydoréduction. Une brève exposition de la gencive à l’air provoque des changements dans le métabolisme des cellules et du système d’oxydoréduction. Il n’y a pas de variation notable dans les composés intermédiaires du cycle pyridinique

    The event generator DECAY4 for simulation of double beta processes and decay of radioactive nuclei

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    The computer code DECAY4 is developed to generate initial energy, time and angular distributions of particles emitted in radioactive decays of nuclides and nuclear (atomic) deexcitations. Data for description of nuclear and atomic decay schemes are taken from the ENSDF and EADL database libraries. The examples of use of the DECAY4 code in several underground experiments are described.Comment: 8 pages, 1 fi

    Local and global Fokker-Planck neoclassical calculations showing flow and bootstrap current modification in a pedestal

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    In transport barriers, particularly H-mode edge pedestals, radial scale lengths can become comparable to the ion orbit width, causing neoclassical physics to become radially nonlocal. In this work, the resulting changes to neoclassical flow and current are examined both analytically and numerically. Steep density gradients are considered, with scale lengths comparable to the poloidal ion gyroradius, together with strong radial electric fields sufficient to electrostatically confine the ions. Attention is restricted to relatively weak ion temperature gradients (but permitting arbitrary electron temperature gradients), since in this limit a delta-f (small departures from a Maxwellian distribution) rather than full-f approach is justified. This assumption is in fact consistent with measured inter-ELM H-Mode edge pedestal density and ion temperature profiles in many present experiments, and is expected to be increasingly valid in future lower collisionality experiments. In the numerical analysis, the distribution function and Rosenbluth potentials are solved for simultaneously, allowing use of the exact field term in the linearized Fokker-Planck collision operator. In the pedestal, the parallel and poloidal flows are found to deviate strongly from the best available conventional neoclassical prediction, with large poloidal variation of a different form than in the local theory. These predicted effects may be observable experimentally. In the local limit, the Sauter bootstrap current formulae appear accurate at low collisionality, but they can overestimate the bootstrap current near the plateau regime. In the pedestal ordering, ion contributions to the bootstrap and Pfirsch-Schluter currents are also modified

    Early predictors of smoking cessation after myocardial infarction

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    The determinants of long-term smoking cessation were evaluated in 80 patients who smoked cigarettes and survived a myocardial infarction. All patients underwent a program of rehabilitation and secondary prevention including in-hospital counseling and physician-guided reinforcing sessions at 1, 3, and 6 months after discharge. At 18 months of follow-up, 53 patients (66.3%) had quit smoking. Variables associated with smoking cessation were duration of hospital stay greater than or equal to 19 days (79 vs. 48%; p less than 0.005) and peak creatine phosphokinase (CPK) elevation greater than or equal to 500 U/l (76 vs. 54%; p less than 0.05). Males tended to quit in higher proportion than females (68 vs. 44%). Age, prior myocardial infarction, other cardiovascular risk factors, infarction location, Killip class at entry, and duration of stay in coronary care unit did not significantly affect the quitting rates. Logistic regression analysis singled out the duration of hospital stay as a significant predictor of smoking cessation (p less than 0.005). Early and intensive secondary prevention during the hospital stay is crucial in promoting sustained smoking cessation after myocardial infarction
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