<i>Introduction to Phase Transitions and Critical Phenomena</i>

Stanley, H. Eugene; Ahlers, Guenter

doi:10.1063/1.3127900

Cited by 2,014 publications

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“…This stability of the probability distribution over a range of time scales indicates that the underlying dynamic mechanisms controlling the activity have similar statistical properties on different time scales. Statistical self-similarity is a defining characteristic of fractal objects [15][16][17] and is reminiscent of a wide class of physical systems with universal scaling properties [15,18]. Our finding of a universal form of the probability distribution raises the possibility of an intrinsic mechanism that influences activity values in a self-similar "fractal" manner, that is unrelated to the individual's daily and weekly schedules, reactions to the environment, the average level of activity, the phase of the circadian pacemaker, and the time scale of observation.…”

Section: Resultsmentioning

confidence: 99%

Non-random fluctuations and multi-scale dynamics regulation of human activity

Ivanov

Chen

et al. 2004

Physica A: Statistical Mechanics and its Applications

144

173

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We investigate if known extrinsic and intrinsic factors fully account for the complex features observed in recordings of human activity as measured from forearm motion in subjects undergoing their regular daily routine. We demonstrate that the apparently random forearm motion possesses dynamic patterns characterized by robust scale-invariant and nonlinear features. These patterns remain stable from one subject to another and are unaffected by changes in the average activity level that occur within individual subjects throughout the day and on different days of the week, since they persist during daily routine and when the same subjects undergo time-isolation laboratory experiments designed to account for the circadian phase and to control the known extrinsic factors. Further, by modeling the scheduled events imposed throughout the laboratory protocols, we demonstrate that they cannot account for the observed scaling patterns in activity fluctuations. We attribute these patterns to a previously unrecognized intrinsic nonlinear multi-scale control mechanism of human activity that is independent of known extrinsic factors such as random and scheduled events, as well as the known intrinsic factors which possess a single characteristic time scale such as circadian and ultradian rhythms.

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Section: Resultsmentioning

confidence: 99%

Non-random fluctuations and multi-scale dynamics regulation of human activity

Ivanov

Chen

et al. 2004

Physica A: Statistical Mechanics and its Applications

144

173

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“…Thus, in terms of Modern Critical Theory 83 [506,507], during a critical transition point the macroscopic manifestation (OM) is essentially based on a kind of abstraction from the original micro-level (neuronal assemblies with their local electromagnetic fields), with all but those micro-level features preserved (operations of neuronal assemblies) that now determine the novel macroscopic observable (OM) and presenting in fact a different biophysical state [38]. That is, the micro-level elements (neuronal assemblies) can now explore different structural relationships with each other.…”

Section: The Succession Of Oms and The Stream Of Consciousnessmentioning

confidence: 99%

Natural world physical, brain operational, and mind phenomenal space–time

Fingelkurts

Neves

2010

Physics of Life Reviews

168

233

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Concepts of space and time are widely developed in physics. However, there is a considerable lack of biologically plausible theoretical frameworks that can demonstrate how space and time dimensions are implemented in the activity of the most complex life-system -the brain with a mind. Brain activity is organized both temporally and spatially, thus representing space-time in the brain. Critical analysis of recent research on the space-time organization of the brain's activity pointed to the existence of so-called operational space-time in the brain. This space-time is limited to the execution of brain operations of differing complexity. During each such brain operation a particular short-term spatio-temporal pattern of integrated activity of different brain areas emerges within related operational space-time. At the same time, to have a fully functional human brain one needs to have a subjective mental experience. Current research on the subjective mental experience offers detailed analysis of space-time organization of the mind. According to this research, subjective mental experience (subjective virtual world) has definitive spatial and temporal properties similar to many physical phenomena. Based on systematic review of the propositions and tenets of brain and mind space-time descriptions, our aim in this review essay is to explore the relations between the two. To be precise, we would like to discuss the hypothesis that via the brain operational space-time the mind subjective space-time is connected to otherwise distant physical space-time reality.Key words: spatial, temporal, consciousness, cognition, operation, architectonics, EEG, field, metastability, physics, coordinative dynamics, self-organization, cortex.

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“…However, the peaks are very weak, broad, and Lorentzian in shape rather than Gaussian, which indicates short-range spin correlations. To estimate the correlation length, the more intense peak at 30.90°(Q = 1.41 Å À1 ) was fit to a Lorentzian line shape and analyzed using the OrnsteinÀZernike model, 32 …”

Section: Xanesmentioning

confidence: 99%

Local and Average Structures and Magnetic Properties of Sr₂FeMnO_5+y, y = 0.0, 0.5. Comparisons with Ca₂FeMnO₅ and the Effect of the A-Site Cation

Ramezanipour¹,

Greedan²,

Siewenie

et al. 2011

Inorg. Chem.

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Local and average structures and magnetic properties of of Sr2FeMnO5+y, y = 0.0, 0.5. comparisons with Ca2FeMnO5 and the effect of the A-site cation Ramezanipour, Farshid; Greedan, John E.; Siewenie, Joan; Proffen, Th.; Ryan, Dominic H.; Grosvenor, Andrew P.; Donaberger, Ronald L.Contact us / Contactez nous: nparc.cisti@nrc-cnrc.gc.ca. Oxygen-deficient perovskites can have a variety of structures depending on different factors including the degree of anion deficiency and the composition. In this article, the focus is on oxygen-deficient perovskites with the formula A 2 BB 0 O 5+x . The oxygen vacancies can order to form the brownmillerite structure in which the B cations are octahedrally coordinated, forming corner-sharing layers, and the B 0 cations are tetrahedrally coordinated, forming corner-sharing chains. (Figure 1). This longrange vacancy ordering results in a supercell that generally has dimensions with respect to the cubic perovskite cell constant, a p , of a br ≈ 2 1/2 a p , b br ≈ 4a p , and c br ≈ 2 1/2 a p . A number of different space group symmetries are observed, depending on subtle differences in the ordering of the tetrahedral chains within the unit cell. The chains can show either a right-handed (R) or lefthanded (L) orientation and the correlation between the intraand interlayer chain orientations and the resulting space groups are summarized in ABSTRACT: Sr 2 FeMnO 5+y was synthesized under two different conditions, in air and in argon, both of which resulted in a cubic, Pm3m, structure with no long-range ordering of oxygen vacancies. The unit cell constants were found to be a 0 = 3.89328(1) Å for argon (y = 0.0) and a 0 = 3.83075(3) Å for air (y = 0.5). In contrast, Ca 2 FeMnO 5 retains long-range brownmillerite oxygen vacancy ordering for either air or argon synthesis. Remarkably, Sr 2 FeMnO 5.0 oxidizes spontaneously in air at room temperature. A neutron pair distribution function (NPDF) study of Sr 2 FeMnO 5.0 (Ar) showed evidence for local, brownmillerite-like ordering of oxygen vacancies for short distances up to 5 Å. M€ ossbauer spectroscopy results indicate more than one Fe site for Sr 2 FeMnO 5+y (Ar and air), consistent with the noncubic local structure found by NPDF analysis. The isomer shifts and quadrupole splittings in both air-and argon-synthesized materials are consistent with the 3+ oxidation state for Fe in sites with coordination number four or five. This is confirmed by an L-edge XANES study. Mn is almost entirely in the 3+ state for Sr 2 FeMnO 5.0 (Ar), whereas Mn 4+ is predominantly present for Sr 2 FeMnO 5.5 (air). Magnetic susceptibility data show zero-fieldcooled/field-cooled (ZFC/FC) divergences near 50 K for the Ar sample and 25 K for the air sample, whereas Ca 2 FeMnO 5 is longrange G-type antiferromagnetically ordered at 407(2) K. Hyperfine magnetic splitting, observed in temperature-dependent M€ ossbauer measurements, indicates short-range magnetic correlations that persist up to 150 K for Sr 2 FeMnO 5.0 (Ar) and 100 K for Sr 2 FeMnO 5.5 (air), well above the ZF...

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Introduction to Phase Transitions and Critical Phenomena

Cited by 2,014 publications

References 0 publications

Non-random fluctuations and multi-scale dynamics regulation of human activity

Non-random fluctuations and multi-scale dynamics regulation of human activity

Natural world physical, brain operational, and mind phenomenal space–time

Local and Average Structures and Magnetic Properties of Sr₂FeMnO_5+y, y = 0.0, 0.5. Comparisons with Ca₂FeMnO₅ and the Effect of the A-Site Cation

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Introduction to Phase Transitions and Critical Phenomena

Cited by 2,014 publications

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Non-random fluctuations and multi-scale dynamics regulation of human activity

Non-random fluctuations and multi-scale dynamics regulation of human activity

Natural world physical, brain operational, and mind phenomenal space–time

Local and Average Structures and Magnetic Properties of Sr2FeMnO5+y, y = 0.0, 0.5. Comparisons with Ca2FeMnO5 and the Effect of the A-Site Cation

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Local and Average Structures and Magnetic Properties of Sr₂FeMnO_5+y, y = 0.0, 0.5. Comparisons with Ca₂FeMnO₅ and the Effect of the A-Site Cation