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1دورية أكاديمية
المؤلفون: Federico Ettori, Thibaud Coupé, Timothy J. Sluckin, Ezio Puppin, Paolo Biscari
المصدر: Entropy, Vol 26, Iss 2, p 120 (2024)
مصطلحات موضوعية: dynamic phase transition, magnetic defects, quenched disorder, anisotropy, Delaunay triangulation, Science, Astrophysics, QB460-466, Physics, QC1-999
الوصف: We investigate the dynamic phase transition in two-dimensional Ising models whose equilibrium characteristics are influenced by either anisotropic interactions or quenched defects. The presence of anisotropy reduces the dynamical critical temperature, leading to the expected result that the critical temperature approaches zero in the full-anisotropy limit. We show that a comprehensive understanding of the dynamic behavior of systems with quenched defects requires a generalized definition of the dynamic order parameter. By doing so, we demonstrate that the inclusion of quenched defects lowers the dynamic critical temperature as well, with a linear trend across the range of defect fractions considered. We also explore if and how it is possible to predict the dynamic behavior of specific magnetic systems with quenched randomness. Various geometric quantities, such as a defect potential index, the defect dipole moment, and the properties of the defect Delaunay triangulation, prove useful for this purpose.
وصف الملف: electronic resource
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المؤلفون: Federico Ettori, Timothy J. Sluckin, Paolo Biscari
مصطلحات موضوعية: Statistics and Probability, metastable lifetime, dynamic spinodal line, droplets, Statistical Mechanics (cond-mat.stat-mech), Ising model, FOS: Physical sciences, Statistical and Nonlinear Physics, Ising model, defects, metastable lifetime, dynamic spinodal line, droplets, Monte Carlo simulation, defects, Monte Carlo simulation, Condensed Matter - Statistical Mechanics
الوصف: Defects and impurities strongly affect the timing and the character of the (re)ordering or disordering transitions of thermodynamic systems captured in metastable states. In this paper we analyze the case of two-dimensional magnetic systems. We adapt the classical JMAK theory to account for the effects of defects on the free energy barriers, the critical droplet area and the associated metastable time. The resulting predictions are successfully tested against the Monte-Carlo simulations performed by adopting Glauber dynamics, to obtain reliable time-dependent results during the out-of-equilibrium transformations. We also focus on finite-size effects, and study how the spinodal line (separating the singledroplet from the multi-droplet regime) depends on the system size, the defect fraction, and the external field.
29 pages, 10 figuresالوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d68ed37805666028575ddf2db6a0b348Test
http://arxiv.org/abs/2210.02138Test -
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المؤلفون: Thanassis Tiropanis, Timothy J. Sluckin, Maria Priestley
مصطلحات موضوعية: ComputingMilieux_GENERAL, Web technology, World Wide Web, History, Computer science, Computer Science (miscellaneous), Empirical measure
الوصف: Rigorous research into the historical past of Web technology driven innovation becomes timely as technological growth and forecasting are attracting popular interest. Drawing on economic and management literature relating to the typical trends of technological innovation, we examine the long-term development of Web technology in a theoretically informed and empirical manner.An original longitudinal dataset of 20,493 Web-related US patents is used to trace the growth curve of Web technology between the years of 1990 through 2013. We find that the accumulation of corporate Web inventions followed an S-shaped curve which shifted to linear growth after year 2004. This transition is unusual in relation to the traditional S-curve model of technological development that typically approaches a limit. The point of inflection on the S-curve coincided reasonably closely with the timing of the dot-com crash in year 2000. Moreover, we find a complex bi-directional relationship between patenting rates in Web technology and movements in the NASDAQ composite stock index. The implications of these results are discussed in theoretical and practical terms for sustained technological growth. Specific recommendations for different stakeholders in commercial Web development are included.
وصف الملف: text
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::3eb9c4d614a9f6f12a8dcbc85ac7d48aTest
https://eprints.soton.ac.uk/439144Test/ -
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المؤلفون: Thanassis Tiropanis, Timothy J. Sluckin, Maria Priestley
المصدر: WebSci (Companion)
مصطلحات موضوعية: World Wide Web, Web technology, Empirical examination, 020204 information systems, 0202 electrical engineering, electronic engineering, information engineering, Subject (philosophy), Web science, 020201 artificial intelligence & image processing, Cognition, 02 engineering and technology, Sociology, Sociocultural evolution, Theme (narrative)
الوصف: The Web has been the subject of compelling biological metaphors that liken it to an evolving ecosystem. Analogies of this kind could benefit from further theoretical and empirical examination. Evolutionary and cognitive approaches provide not only a powerful theoretical framework to address this theme, but also a heritage of robust analytic tools that can help to quantify complex and subjective social and technological phenomena. The goal of this workshop will be to discuss how evolutionary approaches can inform our understanding of the Web at present, as well as methodological challenges and opportunities to shape its evolution into the future.
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::d1248d960867c299d2ed58f819450eceTest
https://doi.org/10.1145/3394332.3402899Test -
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المصدر: Briefings in Bioinformatics. 20:1997-2008
مصطلحات موضوعية: Computer science, 0206 medical engineering, 02 engineering and technology, Computational biology, Variation (game tree), Genome, Linkage Disequilibrium, DNA sequencing, Machine Learning, 03 medical and health sciences, Animals, Humans, Selection, Genetic, Molecular Biology, Selection (genetic algorithm), 030304 developmental biology, Recombination, Genetic, Whole genome sequencing, Likelihood Functions, 0303 health sciences, Natural selection, Haplotypes, Adaptation, Selective sweep, 020602 bioinformatics, Information Systems
الوصف: Insights into genetic loci which are under selection and their functional roles contribute to increased understanding of the patterns of phenotypic variation we observe today. The availability of whole-genome sequence data, for humans and other species, provides opportunities to investigate adaptation and evolution at unprecedented resolution. Many analytical methods have been developed to interrogate these large data sets and characterize signatures of selection in the genome. We review here recently developed methods and consider the impact of increased computing power and data availability on the detection of selection signatures. Consideration of demography, recombination and other confounding factors is important, and use of a range of methods in combination is a powerful route to resolving different forms of selection in genome sequence data. Overall, a substantial improvement in methods for application to whole-genome sequencing is evident, although further work is required to develop robust and computationally efficient approaches which may increase reproducibility across studies.
وصف الملف: text
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::8ef3302399fa144deef249c8f77648d5Test
https://doi.org/10.1093/bib/bby064Test -
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المؤلفون: Simon J. Cox, Timothy J. Sluckin, Gereon A. Kaiping
المصدر: Journal of Theoretical Biology. 405:116-126
مصطلحات موضوعية: 0301 basic medicine, Statistics and Probability, Time Factors, genetic structures, Movement, Population Dynamics, Genetic Fitness, Metapopulation, Biology, 01 natural sciences, General Biochemistry, Genetics and Molecular Biology, Microeconomics, 03 medical and health sciences, Punishment, 0103 physical sciences, Public goods game, Cooperative Behavior, 010306 general physics, Evolutionary dynamics, Group competition, General Immunology and Microbiology, Ecology, Applied Mathematics, General Medicine, 030104 developmental biology, Group selection, Modeling and Simulation, Mutation, Cooperative behavior, General Agricultural and Biological Sciences
الوصف: The stable presence of punishing strategies in various cooperative species is a persistent puzzle in the study of the evolution of cooperation. To investigate the effect of group competition, we study the evolutionary dynamics of the Public Goods Game with punishment in a metapopulation that consists of separate communities. In addition to (a) well-mixed non-interacting communities, we model three distinct types of interaction between communities, (b) Migration independent of fitness; (c) Competition between whole communities, where entire communities replace each other depending on average fitness; (d) Migration where the probability of an offspring replacing an individual in another community depends on fitness. We use stochastic simulations to study the long-run frequencies of strategies with these interactions, subject to high mutation and migration rates. In cases (a) and (b), the transition between cooperation/punishment and defection regimes occurs for similar parameter values; with migration (b), the transitions are steeper due to higher total mixing. Fitness-based migration (d) by contrast can help support cooperation, changing the locations of transitions, but while group selection (c) does stabilise cooperation over much of the parameter space, fitness-based migration (d) acts as a proxy for group selection only in a smaller region.
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::79f5884978e3bf99f5c47f969972046aTest
https://doi.org/10.1016Test/j .jtbi.2015.12.016 -
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المؤلفون: Alexander Mörseburg, Florian Clemente, Mario Mitt, Toomas Kivisild, Tiago Antao, Guy S. Jacobs, Georgi Hudjashov, Mait Metspalu, Charlotte E. Inchley, Maru Mormina, Christina A. Eichstaedt, Alexia Cardona, Luca Pagani, Timothy J. Sluckin, Reedik Mägi, Ene Metspalu
المصدر: Genes and environment.
مصطلحات موضوعية: Vital capacity, education.field_of_study, business.industry, Population, Effects of high altitude on humans, Hypoxia (medical), Pulmonary function testing, Evolutionary biology, Medicine, Allele, medicine.symptom, education, business, Gene, Selection (genetic algorithm)
الوصف: Background: High altitude is characterised by hypoxia, arid climate, high solar radiation and other environmental stressors. Andeans have resided at high elevations for several millennia and have developed an unique array of physiological adaptations. However, the genetic changes that led to these adaptations remain largely elusive. Objective: The aim of this study is to identify genetic variants that harbour signatures of recent positive selection and may facilitate physiological adaptations to hypobaric hypoxia. Methods: We conducted whole genome sequencing and lung function tests in 19 Argentinean highlanders (>3500 m) comparing them to 16 lowlanders. We developed a new statistical procedure using a combination of population branch statistics and number of segregating sites by length to detect beneficial alleles that arose since the settlement of the Andes and are currently present in 15-50% of the population. Results: We identified two missense variants as significant targets of selection. One variant is located within the GPR126 gene and has been previously associated with the forced expiratory volume/forced vital capacity ratio. The derived allele of GPR126 is also associated with lung function in our sample of highlanders (p Conclusions: These variants may contribute to the physiological adaptations to hypobaric hypoxia, possibly by altering lung function and preventing excessive erythrocytosis and hypoxia induced pulmonary hypertension in Andean populations.
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::83a09ae63664abc16fd5ec8a1c341428Test
https://doi.org/10.1183/13993003.congress-2018.pa1274Test -
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مصطلحات موضوعية: Materials science, Condensed matter physics, Shell (structure), General Physics and Astronomy, Metamaterial, Physics::Optics, 02 engineering and technology, Dielectric, 021001 nanoscience & nanotechnology, 01 natural sciences, 010309 optics, Core (optical fiber), Liquid crystal, 0103 physical sciences, Particle, 0210 nano-technology, Anisotropy, Plasmon
الوصف: Core-shell building blocks have been found useful in recent years as inclusions, in the search for metamaterials with tailored properties. Either the core or the shell of these composite inclusions may be metallic, and the dielectric component may be both radially anisotropic and radially inhomogeneous. In tunable anisotropic metamaterials, the tuning may then be achieved through the host, the core, or some combination thereof. However a theoretical picture is harder to build. Here we propose an approach to an effective medium theory for such materials, valid in the quasi-static limit. The method proceeds first by homogenising the interior of complex particle, and then uses standard anisotropic effective medium methods to provide bulk effective homogenized parameters. By varying the degree of inhomogeneity in the core, shell and dielectric-metal material volume fractions, the technique can be used as a tool for the design of metamaterials with specifically engineered properties. We find that metamaterial properties can be readily tuned by reorienting the optical axis of the host (e.g. liquid crystal). In particular, there is a possibility of switching between hyperbolic and conventional anisotropic metamaterial properties bychanging inclusion shell properties.
وصف الملف: text
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::604e8265bbc4b948fef64d75dce5ef06Test
https://eprints.soton.ac.uk/423429Test/ -
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المؤلفون: Tung B.T. To, Geoffrey R. Luckhurst, Timothy J. Sluckin
المصدر: Liquid Crystals. 43:1448-1461
مصطلحات موضوعية: Materials science, Condensed matter physics, Biaxial nematic, Bent molecular geometry, 02 engineering and technology, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Condensed Matter::Soft Condensed Matter, Transverse plane, Dipole, Liquid crystal, Phase (matter), 0103 physical sciences, Polar, General Materials Science, Field theory (psychology), 010306 general physics, 0210 nano-technology
الوصف: We have studied a polar, biaxial nematic liquid crystal formed from bent-core molecules using molecular field theory. The model includes a simple Heisenberg-form dipolar intermolecular interaction in addition to the usual quadrupolar nematic interaction, and mimics a system consisting of nematogenic bent-core molecules with a large transverse dipole along the bisector of the two molecular arms. Such systems are regarded as good candidates for biaxial nematic liquid crystals. In principle, the molecular dipoles can align, thus stabilising the ordering of the minor axes. Our calculations predict that, for suitable values of the bent-core interarm angle, the biaxial nematic phase can be stabilised at higher temperatures than in the absence of the transverse dipole. In general, the transverse macroscopic polar order stabilises the biaxial nematic phase. In particular, for a large enough dipolar interaction, the Landau point in the pure biaxial nematic develops into a line of first-order polar biaxial ...
وصف الملف: text
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::33b21741051d5355005e47d2874cd8d3Test
https://doi.org/10.1080/02678292.2016.1181214Test -
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المؤلفون: Tung B.T. To, Geoffrey R. Luckhurst, Timothy J. Sluckin
المصدر: The Journal of Chemical Physics. 152:189902
مصطلحات موضوعية: Materials science, Condensed matter physics, Liquid crystal, Published Erratum, General Physics and Astronomy, Field theory (psychology), Physical and Theoretical Chemistry
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::028bc8e37f87fd2ee41891b66668fb22Test
https://doi.org/10.1063/5.0010693Test
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