330 research outputs found

    Evolving localizations in reaction-diffusion cellular automata

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    We consider hexagonal cellular automata with immediate cell neighbourhood and three cell-states. Every cell calculates its next state depending on the integral representation of states in its neighbourhood, i.e. how many neighbours are in each one state. We employ evolutionary algorithms to breed local transition functions that support mobile localizations (gliders), and characterize sets of the functions selected in terms of quasi-chemical systems. Analysis of the set of functions evolved allows to speculate that mobile localizations are likely to emerge in the quasi-chemical systems with limited diffusion of one reagent, a small number of molecules is required for amplification of travelling localizations, and reactions leading to stationary localizations involve relatively equal amount of quasi-chemical species. Techniques developed can be applied in cascading signals in nature-inspired spatially extended computing devices, and phenomenological studies and classification of non-linear discrete systems.Comment: Accepted for publication in Int. J. Modern Physics

    Upper quantum Lyapunov Exponent and Anosov relations for quantum systems driven by a classical flow

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    We generalize the definition of quantum Anosov properties and the related Lyapunov exponents to the case of quantum systems driven by a classical flow, i.e. skew-product systems. We show that the skew Anosov properties can be interpreted as regular Anosov properties in an enlarged Hilbert space, in the framework of a generalized Floquet theory. This extension allows us to describe the hyperbolicity properties of almost-periodic quantum parametric oscillators and we show that their upper Lyapunov exponents are positive and equal to the Lyapunov exponent of the corresponding classical parametric oscillators. As second example, we show that the configurational quantum cat system satisfies quantum Anosov properties.Comment: 17 pages, no figur

    Cellular automaton supercolliders

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    Gliders in one-dimensional cellular automata are compact groups of non-quiescent and non-ether patterns (ether represents a periodic background) translating along automaton lattice. They are cellular-automaton analogous of localizations or quasi-local collective excitations travelling in a spatially extended non-linear medium. They can be considered as binary strings or symbols travelling along a one-dimensional ring, interacting with each other and changing their states, or symbolic values, as a result of interactions. We analyse what types of interaction occur between gliders travelling on a cellular automaton `cyclotron' and build a catalog of the most common reactions. We demonstrate that collisions between gliders emulate the basic types of interaction that occur between localizations in non-linear media: fusion, elastic collision, and soliton-like collision. Computational outcomes of a swarm of gliders circling on a one-dimensional torus are analysed via implementation of cyclic tag systems

    Universal computation with limited resources: Belousov-Zhabotinsky and Physarum computers

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    Using the examples of an excitable chemical system (Belousov-Zhabotinsky medium) and plasmodium of Physarum polycephalum we show that universal computation in a geometrically unconstrained medium is only possible when resources (excitability or concentration of nutrients) are limited. In situations of limited resources the systems studied develop travelling localizations. The localizations are elementary units of dynamical logical circuits in collision-based computing architectures.Comment: Int. J. Bifurcation and Chaos (2008), accepte

    12-Pulse LCI synchronous drive for a 20 MW compressor : modeling, simulation and measurements

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    Abstract – The current source thyristor inverter is still today a suitable choice for supplying high power adjustable speed drives for pumps or compressors. This paper presents a 12-pulse LCI (load commutated inverter) synchronous drive for a 20 MW compressor, it focuses on the following main aspects: modeling of the complete drive system, numerical simulation and comparison between calculated and measured values of the pulsating torque components in steady-state operations. The modeling of the six- phase synchronous motor is obtained by using a new virtual test- platform for large electrical machines. The pulsating torque components are measured in real time with a digital transient torque measurement device

    The Real-World Observational Prospective Study of Health Outcomes with Dulaglutide and Liraglutide in Type 2 Diabetes Patients (TROPHIES): Design and Baseline Characteristics

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    Introduction: The TROPHIES observational study enrolled patients with type 2 diabetes mellitus (T2DM) initiating their first injectable treatment with the glucagon-like peptide 1 receptor agonists (GLP-1 RAs) dulaglutide or liraglutide. This manuscript focuses on the study design, baseline characteristics of the enrolled population, and factors associated with GLP-1 RA choice. Methods: TROPHIES is a prospective, observational, 24-month study conducted in France, Germany, and Italy. Inclusion criteria include adult patients with T2DM, naĂŻve to injectable antihyperglycemic treatments, initiating dulaglutide or liraglutide per routine clinical practice. The primary outcome is the duration of treatment on dulaglutide or liraglutide without a significant treatment change. Results: The analysis included 2181 patients (dulaglutide, 1130; liraglutide, 1051) (cutoff date May 15, 2019). The population was 56% male with mean [standard deviation (SD)] patient characteristics at baseline as follows: age, 59.2 (11.0) years; body mass index (BMI), 33.9 (6.6) kg/m2; T2DM duration, 8.5 (6.9) years; and glycated hemoglobin (HbA1c), 8.2 (1.3)%. Between-cohort demographic and clinical characteristics were balanced. The mean (SD) HbA1c and BMI values for French, German, and Italian patients were, respectively, 8.6 (1.4)%, 8.2 (1.4)%, 8.0 (0.8)%; 33.3 (6.1) kg/m2, 36.0 (7.2) kg/m2, and 32.6 (5.9) kg/m2. Conclusion: This study analysis at baseline provides an opportunity to evaluate between-country differences in baseline HbA1c, weight, macrovascular complications, and factors driving GLP-1 RA selection for patients with T2DM in daily practice

    Seismic structure and activity of the north-central Lesser Antilles subduction zone from an integrated approach: similarities with the Tohoku forearc

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    The 300 km long north-central segment of the Lesser Antilles subduction zone, including Martinique and Guadeloupe islands has been the target of a specific approach to the seismic structure and activity by a cluster of active and passive offshore-onshore seismic experiments coordinated within the ¿Thales was right¿ proposal to the European Union action (Laigle et al., Tectonophys., in rev.) The top of the subducting plate can be followed under the wide accretionary wedge by a dense grid of dip- and strike-lines of multichannel reflection seismics. This reveals the hidden updip limit of the contact of the upper plate crustal backstop thrust onto the slab. Two OBS refraction seismic profiles constrained a 26 km large crustal thickness from the volcanic arc throughout the forearc domain (Kopp et al., EPSL, 2011). These new observations imply a three times larger width of the potential interplate seismogenic zone under the marine domain of the Caribbean plate with respect to a regular intra-oceanic subduction zone, in the common assumption that the upper plate Moho contact on the slab is a proxy of its downdip limit. Towards larger depth under the mantle corner, the top of the slab imaged from the conversions of teleseismic body-waves and the locations of earthquakes from the dense temporary array of 80 OBS and land seismometers appears with kinks which increase the dip from 10-20° under the forearc domain, to 60° on the segment from 70 km depth down to under the volcanic arc. There, at 140 km depth just north of Martinique the 2007 M 7.4 earthquake, largest for half a century, was accompanied by an increased seismic activity over the whole depth range, which provides a new focused image thanks to the OBS and land deployments. A double-planed dipping slab seismicity is thus now resolved, as originally discovered in Tohoku ( NE Japan) and since in some other subduction zones. Other types of seismic activity uniquely observed in Tohoku, are resolved now here, such as ¿supraslab¿ earthquakes with normal-faulting focal mechanisms reliably located in the mantle corner and ¿deep flat-thrust¿ earthquakes at 45 km depth on the interplate fault under the Caribbean plate forearc mantle. None such types of seismicity should occur under the paradigm of a regular peridotitic mantle of the upper plate which is serpentinized by the fluids provided from the dehydrating slab beneath, and which is commonly considered as limiting the downward extent of the interplate seismic coupling. If the upper plate here comprised lithospheric segments related to the earlier formation of the Caribbean oceanic plateau by the material advection from a mantle plume, it could then be underlain by a correspondingly modified, heterogeneous mantle, which may impose regions of stick-slip behaviour on the interplate under the mantle corner among stable-gliding areas. The Tohoku 2011 M9 earthquake was unexpected not only in its slip reaching to the trench, but also in its slip reaching far under the mantle corner against the serpentinization decoupling paradigm, and its structural setting may be revisited for resolving corresponding structural heterogeneityPeer Reviewe

    e-Work Self-Efficacy digital competence and work engagement of teachers in public secondary schools from two provinces in the Philippines

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    This descriptive-correlational research design aimed to determine the significant relationships between e-Work SelfEfficacy digital competence, and work engagement of teachers in secondary schools in the Philippines. The respondents of the study were 244 teachers from public secondary from two provinces. They were selected through Simple Random Sampling. The study was conducted via online forms. The gathered data were treated using statistical tools such as Mean, Standard Deviation, Pearson r, Hayes Process, and Multiple Linear Regression. The results of the study suggest that enhancing e-Work Self-Efficacy and digital competence may lead to increased work engagement, which could ultimately lead to better job performance and satisfaction in the context of remote work. The results of moderation analyses revealed that the respondents’ profile age, length of service, and academic rank significantly moderated the relationship between e-Work Selt-Efficacy and work engagement. Hence, the hypothesis stating that the respondents’ profile variables do not significantly moderate between e-Work Self-Efficacy and work engagement and also the hypothesis stating that the respondents’ profile variables do not significantly moderate between digital competence and work engagement of the respondents were both partly upheld. The result of regression analysis identified that digital competence singly predicted the Work Engagement of the respondents. Moreover, the regression further revealed that digital competence and e-Work Selt-Efficacy, in combination, predict the work engagement of the respondents. Hence, the hypothesis stating that the respondents’ profile, e-Work Self-Efficacy and digital competence do not significantly predict their work engagement was partly upheld
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