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Summary A description in terms of phase and amplitude variables is given for nonlinear oscillators subject to white Gaussian noise described by Ito stochastic differential equations. The stochastic differential equations derived for the amplitude and the phase are rigorous, and their validity is not limited to the weak noise limit. It is shown that if Floquet vectors are used, then in the neighborhood of a limit cycle the phase variable coincides with the asymptotic phase defined through isochrons. Two techniques for the analysis of the phase and amplitude equations are discussed, that is, asymptotic expansion method and a phase reduction procedure based on projection operators technique. Formulas for the expected angular frequency, expected oscillation amplitude, and amplitude variance are derived using Ito calculus. Copyright © 2016 John Wiley & Sons, Ltd.

A rigorous methodology that combines a fully quantum mechanical treatment of a small system with a classical trajectory description of a large number of degrees of freedom is discussed in connection with the mechanism of decoherence. The need for mean field approximations in traditional quantum-classical calculations is removed by abandoning the delocalized wavefunction description of the quantum particle in favor of Feynman's formulation, which is based on local paths. The effects of the environment enter the quantum-classical path integral (QCPI) expression in terms of phase factors along classical trajectories, whose number grows exponentially with the number of time steps. It is argued that memory loss allows termination of trajectory branching and that the main contribution to decoherence arises from a single classical trajectory (from each sampled initial condition). Exploiting these ideas allows a dramatic reduction in the required number of trajectories, making QCPI calculations feasible. © 2015 Wiley Periodicals, Inc.

SummaryObjectives Female obesity is a state of relative hypogonadotrophic hypogonadism. The aim of this study is to examine gonadotrophin secretion and response to gonadotrophin-releasing hormone (GnRH) in the luteal phase of the menstrual cycle and to investigate the pharmacodynamics and pharmacokinetics of endogenous and exogenous luteinizing hormone (LH) in obese women. Design Participants underwent a luteal phase frequent blood sampling study. Endogenous LH pulsatility was observed, gonadotrophin-releasing hormone (GnRH) was given in two weight-based doses, and GnRH antagonist was administered followed by recombinant LH. Patients Regularly menstruating obese (n = 10) and normal weight (n = 10) women. Measurements Endogenous hypothalamic-pituitary function (as measured by LH pulsatility), pituitary sensitivity (GnRH-induced LH secretion), pharmacodynamics of endogenous LH and pharmacokinetics of exogenous LH were compared between the obese and normal weight groups. Results There were no statistically significant differences in endogenous LH pulsatility or pituitary responses to two weight-based doses of GnRH between the obese and normal weight women. There were no differences in the pharmacodynamics of endogenous LH or the pharmacokinetics of exogenous LH between the groups. FSH dynamics did not differ between the groups throughout the study. Conclusions The relative hypogonadotrophic hypogonadism of obesity cannot be explained by differences in LH and FSH luteal phase dynamics or differences in endogenous LH pharmacodynamics or exogenous LH pharmacokinetics.

Spore photoproduct lyase (SPL) catalyzes the repair of the UV lesion spore photoproduct (SP) in a reaction dependent on S-adenosyl-l-methionine (SAM). We have utilized H/D exchange to show that in the presence of SAM, a significant reduction in H/D exchange is observed upon binding SPTpT or undamaged oligonucleotide, indicating a shift of 20 or 10 amide protons, respectively, from a rapidly-exchangable state to a fully-protected conformation. In the absence of SAM, neither the oligonucleotide nor the SPTpT produce a significant perturbation in H/D exchange, indicating SAM is a requisite binding partner. Performing the same experiments in aerobic conditions reduced the magnitude of ligand-induced structural changes, consistent with the importance of the oxygen-sensitive iron–sulfur cluster for SAM and substrate binding.

Study of weakly non-linear dynamics of a reaction–super-diffusion system near a Hopf bifurcation by means of fractional analogues of complex Ginzburg-Landau and Kuramoto-Sivashinsky equations is presented. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

SUMMARY Aim A major question with regard to the ecology of temperate rain forests in south-central Chile is how pioneer and shade-tolerant tree species coexist in old- growth forests. We explored the correspondence between tree regeneration dynamics and life-history traits to explain the coexistence of these two functional types in stands apparently representing a non-equilibrium mixture. Location This study was conducted in northern ChiloeIsland, Chile (41.6� S, 73.9� W) in a temperate coastal rain forest with no evidence of stand disruption by human impact. Methods We assessed stand structure by sampling all stems within two 50 · 20 m and four 5 · 100 m plots. A 600-m long transect, with 20 uniformly spaced sampling points, was used to quantify seedling and sapling densities, obtain increment cores, and randomly select 10 tree-fall gaps. We used tree-ring analysis to assess establishment periods and to relate the influences of disturbances to the regeneration dynamics of the main canopy species. Results Canopy emergent tree species were the long-lived pioneer Eucryphia cordifolia and the shade-tolerant Aextoxicon punctatum. Shade-tolerant species such as Laureliopsis philippiana and several species of Myrtaceae occupied the main canopy. The stem diameter distribution for E. cordifolia was distinctly unimodal, while for A. punctatum it was multi-modal, with all age classes represented. Myrtaceae accounted for most of the small trees. Most tree seedlings and saplings occurred beneath canopy gaps. Based on tree-ring counts, the largest individuals of A. punctatum and E. cordifolia had minimum ages estimated to be > 350 years and > 286 years, respectively. Shade-tolerant Myrtaceae species and L. philippiana had shorter life spans (< 200 years). Most growth releases, regardless of tree species, were moderate and have occurred continuously since 1750. Main conclusions We suggest that this coastal forest has remained largely free of stand-disrupting disturbances for at least 450 years, without substantial changes in canopy composition. Release patterns are consistent with this hypothesis and suggest that the disturbance regime is dominated by individual tree-fall gaps, with sporadic multiple tree falls. Long life spans, maximum height and differences in shade tolerance provide a basis for understanding the long- term coexistence of pioneer and shade-tolerant tree species in this coastal, old- growth rain forest, despite the rarity of major disturbances.

We investigated several three-state molecular models interacting with an on/off-resonant two-mode squeezed vacuum field (TSV) to clarify the detuning effects on the dynamic behaviors of on/off-diagonal molecular density matrices. For comparison, we perform a parallel study in which the initial field is an on/off-resonant two-mode coherent field. In the case of satisfying both a large one-photon detuning and a two-photon resonance conditions, the magnitude of off-diagonal density matrix (13) between the second excited and the ground states for (TSV) exhibits distinct increase and decrease behaviors similar to the case of a two-mode coherent field in contrast to the case of one- and two-photon resonances, in which a random oscillation of 13 with a relatively high averaged value is observed. The change in the contribution of one- and two-photon processes due to the detuning of external fields and the differences in the quantum statistics of the initial quantum fields are found to cause such attractive variations in dynamics of the coherency between molecular electronic states as well as their populations. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem 99: 421- 430, 2004

Spatially periodic equilibria A(X, T) = 1 - q2 eiqX+i0 are the locally preferred planform for the Ginzburg-Landau equation TA = 2XA + A - A|A|2. To describe the global spatial behavior, an evolution equation for the local wave number q can be derived formally. The local wave number q satisfies approximately a so called phase diffusion equation q = 2h(q). It is the purpose of this paper to explain the extent to which the phase diffusion equation is valid by proving estimates for this formal approximation.

In this paper, a feedback control law based on two time‐scale assignment and state extension is implemented for the nonlinear non‐minimum phase dynamics of three degree‐of‐freedom autonomo...

We examine the impact of small parity-time () symmetric perturbations on nonlinear optical honeycomb lattices in the tight-binding limit. We show for strained lattices that complex dispersion relationships do not form under perturbation, and we find a variety of nonlinear wave equations which describe the effective dynamics in this regime. The existence of semilocalized gap solitons in this case is also shown, though we numerically demonstrate these solitons are likely unstable. We show for unstrained lattices under the effect of a restricted class of perturbations, which prevent complex dispersion relationships from appearing, that nontrivial phase dynamics emerge as a result of the perturbation. This phase can be understood as momentum imparted to optical beams by the lattice, thus showing perturbations offer potentially novel means for the control of light in honeycomb lattices.

Previous studies have shown only modest effects of supramammillary nucleus (SuM) dysfunction on theta frequency and learning in the water maze (WM), with larger effects in other tasks. However, theta recorded from SuM, and used to trigger the production of theta-like oscillations in the hippocampus, produced reversal of the deficit in WM learning produced by theta blocking. We explored this apparent inconsistency by analyzing the relationship between SuM and hippocampal theta in the control group of this theta-blocking experiment using coherence, phase analysis, and the directed transfer function. We found little evidence of an influence of SuM on the hippocampus in the bulk of WM learning-with some possibility of SuM becoming involved briefly later in learning. A learning-related increase in coherence was observed in conjunction with gradual phase reorganization of hippocampal theta in relation to SuM theta. This change in phase dynamics between the two structures was also correlated with a relative increase of the estimated direction of theta propagation from the SuM to the hippocampus. These results are consistent with the previous weak effects of SuM lesions and suggest that the use of SuM as a source to trigger hippocampal theta and recover function is likely to be due to coherence between SuM and some other structure that normally controls hippocampal theta during WM learning.

Modeling ionic reactions in a dynamic environment, such as in a solvent cage, requires the generation of tailor-made ionic adducts involved in the process and the investigation of the intrinsic structural and electronic factors governing their behavior in the unsolvated state. A compendium of the most recent studies on the gas-phase dynamics and reactivity of chiral ion–dipole pairs involved in classical organic reactions is reported, together with a presentation of the experimental and theoretical methodologies adopted. Copyright © 2004 John Wiley & Sons, Ltd.

Purpose: This study aims to assess the phase relationship of prefrontal tissue oxyhemoglobin oscillations using wavelet phase coherence analysis of cerebral Delta [HbO2] signals in cerebral infarction (CI) patients during the resting state. Methods: Continuous recordings of near-infrared spectroscopy signals were obtained from the left and right prefrontal lobes in 21 subjects with CI (Group CI, age: 76.6 ± 8.5 yr) and 21 healthy elderly subjects (Group Healthy, age: 69.0 ± 7.4 yr) during the resting state. The Group CI was further divide into two groups: CI with hypertension and CI without hypertension. The phase synchronization between left and right prefrontal Delta [HbO2] oscillations in four frequency intervals (I, 0.6–2 Hz; II, 0.145–0.6 Hz; III, 0.052–0.145 Hz; and IV, 0.021–0.052 Hz) was analyzed using wavelet phase coherence method. Results: The phase coherences in intervals III and IV were significantly lower in CI with hypertension than in healthy elderly subjects (F = 12.974, p = 0.001 for III and F = 10.073, p = 0.004 for interval IV). The phase coherence of CI without hypertension in interval III was significantly lower than in healthy elderly subjects (F = 9.909, p = 0.004). Also, the phase coherence in interval IV was significantly lower in CI with hypertension than in CI without hypertension (F = 5.665, p = 0.028). Also, the phase agreement in interval IV showed evident difference between Group CI with hypertension and without hypertension. Conclusions: The difference in phase characteristics of prefrontal tissue oxyhemoglobin oscillations between the CI patients and healthy elderly indicates altered phase synchronization. Moreover, the CI combined with hypertension would aggravate this process. This study provides new insight into the phase dynamics of cerebral oxygenation and may be useful in assessing the risk for stroke.

Models useful in the dynamic method for KLa measurements are developed and compared. Particular attention is given to the gas phase dynamics and the oxygen electrode response time. Comparisons and error calculations are based on computer simulations. Correction factors are presented for a range of dimensionless parameters. In general, the errors resulting from neglecting the gas phase dynamics and the electrode response can be expected to be large.

The sections in this article are: 1 Analytical Techniques and Terms 1.1 Biomechanics Terminology 1.2 Dynamics Variables 1.3 Single vs. Multiple Degrees of Freedom 1.4 Free-Body Diagram 1.5 Dynamics Techniques 2 Insights from Inverse Dynamics 2.1 Equations of Motion 2.2 Anthropometric Data 2.3 Predictions Using an Inverse Dynamics Model 3 Control of Different Locomotion Forms 3.1 Swing-Phase Dynamics 3.2 Stance-Phase Dynamics 3.3 Insights for Neural Control of Locomotion 4 Role of Dynamics in the Control of Arm Movements 4.1 Limb Postural Dynamics 4.2 Intersegmental Dynamics Change with Practice 5 Changes in Limb Dynamics During Development 5.1 Spontaneous Kicking Behaviors 5.2 Acquisition of Reaching 6 Concluding Remarks

This paper investigates the interrelationship between Brent oil price and exchange rate in 10 emerging markets of East Europe, Asia, Africa, and South America. For computational purpose, we apply two innovative methodologies—wavelet coherence and phase difference that are capable of observing different frequency scales. Wavelet coherence results suggest that strong coherence is present during world financial crisis (WFC) in the oil‐exporting countries and in majority of the oil‐importing countries. Phase arrows as well as phase difference suggest negative coherence between oil and exchange rates in the oil‐importing countries during WFC. Negative coherence is found in these countries because currency depreciation was accompanied by immense oil price drop in WFC period. In addition, phase difference has relatively stable in‐phase dynamics in long term in the oil‐importing countries during tranquil periods, which confirms theoretical stance that higher oil prices cause currency depreciation and vice versa. As for the oil‐exporting countries, we find constant and relatively long‐lasting anti‐phase pattern in Russian and Nigerian cases for long‐term horizons but not for Brazilian one.

The availability of high-quality, large-scale, and single-crystal wafer-scale graphene films is fundamental for key device applications in the field of electronics, optics, and sensors. Synthesis determines the future: unleashing the full potentials of such emerging materials relies heavily upon their tailored synthesis in a scalable fashion, which is by no means an easy task to date. This review covers the state-of-the-art progress in the synthesis of wafer-scale graphene films by virtue of chemical vapor deposition (CVD), with a focus on main challenges and present status. Particularly, prevailing synthetic strategies are highlighted on a basis of the discussion in the reaction kinetics and gas-phase dynamics during CVD process. Perspectives with respect to key opportunities and promising research directions are proposed to guide the future development of wafer-scale graphene films.

In some ecosystems a small suite of species can determine community-level patterns of species richness by acting as either ‘accumulators’ or ‘repellers’; that is, the richness of the immediate neighbourhood of such species departs from that expected on the basis of a given null model. Using the individual species-area approach, we evaluated community-level spatial pattern in four species-rich shrublands (two 40 × 40 m and two 30 × 30 m plots) by assessing the frequency of accumulator and repeller species and whether any such species were associated with specific life-history characteristics. Few species departed from the expectations of the null spatial model that we used, although, at three of the four sites, accumulators were more common than repellers. Departures from the null model we assessed were most prevalent within just 1 m of focal individuals and were not consistently associated with specific life-history traits. Model-based clustering suggests that there are distinct sub-communities in each of the four communities, but while internally spatially cohesive, these sub-communities intermingle and their membership is not predictable from the life-history traits of their constituent species. Comparable analyses in other species-rich systems have also detected a similar absence of spatial interactions. The disturbance regime in the shrubland communities we consider is markedly different from those in the forest ecosystems where previous studies have been concentrated (recurrent fire versus infrequent gap-phase dynamics) and resources are more limiting. Thus, our results provide further support for the generality of a model of stochastic geometry, likely underpinned by stochastic dilution effects, in species-rich plant communities.

The persistence of subsonic phase boundaries in a multidimensional Van der Waals fluid is analyzed. The phase boundary is considered as a sharp free boundary that connects liquid and vapor bulk phase dynamics given by the isothermal Euler equations. The evolution of the boundary is driven by effects of configurational forces as well as surface tension. To analyze this problem, the equations and trace conditions are linearized such that one obtains a general hyperbolic initial boundary value problem with higher-order boundary conditions. A global existence theorem for the linearized system with constant coefficients is shown. The proof relies on the normal mode analysis and a linear form in suitable spaces that is defined using an associated adjoint problem. Especially, the associated adjoint problem satisfies the uniform backward in time Kreiss–Lopatinskiĭ condition. A new energy-like estimate that also includes surface energy terms leads finally to the uniqueness and regularity for the found solutions of the problem in weighted spaces. Copyright © 2016 John Wiley & Sons, Ltd.

Handling the aqueous two-phase systems (ATPSs) formed by liquid-liquid phase separation (LLPS) relies on the accurate construction of binodal curves and tie-lines, which delineate the polymer concentrations required for phase separation and depict the properties of the resulting phases, respectively. Various techniques to determine the binodal curves and tie-lines of ATPSs exist, but most rely on manually pipetting relatively large volumes of fluids in a slow and tedious manner. We describe a method to determine ATPS binodals and tie-lines that overcomes these disadvantages: microscale droplet manipulation by electrowetting-on-dielectric (EWOD). EWOD enables automated handling of droplets in an optically transparent platform that allows for in situ droplet observation. Separated phases are clearly visible, and the volumes of each phase are readily determined. Additionally, in considering the molecular crowding present in living cells, this work examines the role of a macromolecule in prompting LLPS. These results show that EWOD-driven droplet manipulation effectively interrogates the phase dynamics of ATPSs and macromolecular crowding in LLPS.

The effect of an external resonator on the emission of a GaAs microcavity with embedded quantum wells is investigated experimentally and theoretically. It was shown that the external resonator controls the process of the stimulated emission of the microcavity leading to the threshold-like appearance of closely separated modes in a spectrum and to oscillations in the temporal dynamics of the emission. Investigation of the spatial coherence with a temporal resolution shows a complex phase dynamics related to the interplay between the lasing modes and reveals a strong spatial inhomogeneity of a phase within each mode.

SUMMARY We analyze the features of the oscillations arising in forced inductor–capacitor (LC) oscillators when they operate in the periodic pulling mode, under the action of a weak injection signal. In radio frequency integrated circuits, both voltage-controlled oscillators subject to undesired couplings and injection-locked frequency dividers behave like forced LC oscillators. These are modeled as second-order driven oscillators working in the subharmonic (secondary) resonance regime. The analysis is based on the generalized Adler's equation, which we introduce to describe the phase dynamics of dividers of any division ratio and to derive closed-form expressions for the spectrum components of the system's oscillatory response. We show that the spectrum is double-sided and asymmetric, unlike the single-sided spectrum of systems with primary resonance. Numerical and experimental results are given to validate the presented results, which significantly generalize those available in the literature. Copyright © 2014 John Wiley & Sons, Ltd.

Urinary hormone analysis was conducted on two adult female Indian rhinoceroses (Rhinoceros unicornis) that exhibited minimal or no estrual behaviors traditionally used to time breeding. Urine was collected throughout two consecutive estrous cycles to establish preliminary data on each individual's pattern and concentration of estrogen conjugates (EC) and progesterone metabolites (PdG) during follicular and luteal phases. Following preliminary endocrine analysis, urine samples were shipped on a frequent basis to verify when each female was off baseline in EC. Estrus and breeding dates were then predicted. Females were introduced to fresh male rhinoceros fecal samples daily throughout the follicular phase to potentially stimulate estrous behaviors. Despite successful assessment of follicular phase dynamics, females sometimes failed to exhibit estrus. Both females conceived following mating introductions that were timed using hormone analysis. Pregnancy was diagnosed either by endocrine analysis or rectal ultrasonography. Progestational support (altrenogest) occurred after pregnancy confirmation and varied for each female (21 and 66 days post-breeding). One female experienced early pregnancy loss and the other successfully completed a term pregnancy. These results demonstrate that a science based management strategy that relies on urinary biomarkers of ovarian function can facilitate naturally breeding captive Indian rhinoceroses.

The fabrication and characterisation of Al—Cu thin film alloys obtained using co-deposition geometry from individual Al and Cu sources were addressed. A compositional gradient ranging from 36 to 93 at.% Cu was obtained. The surface microstructure evolved with a strong influence on the Cu content. This was connected to the presence of the Cu(111) in the alloys. The electrical resistivity showed a decrease by almost one order of magnitude in the Cu rich region of the Al—Cu combinatorial library. Al—Cu thin films evaporated from a single source produced a surface compositional gradient of 7 at.%. X-ray photoelectron spectroscopy (XPS) depth profiling revealed an in-depth compositional gradient as well. This behaviour was attributed to the gas phase dynamics of Al and Cu during the thin film formation.

SUMMARY Based on recent papers that have demonstrated that robust iterative learning control can be based on parameter optimization using either the inverse plant or gradient concepts, this paper presents a unification of these ideas for discrete-time systems that not only retains the convergence properties and the robustness properties derived in previous papers but also permits the inclusion of filters in the input update formula and a detailed analysis of the effect of non-minimum-phase dynamics on algorithm performance in terms of a ‘plateauing’ or ‘flat-lining’ effect in the error norm evolution. Although the analysis is in the time domain, the robustness conditions are expressed as frequency domain inequalities. The special case of a version of the inverse algorithm that can be used to construct a robust stable anti-causal inverse non-minimum-phase plant is presented and analysed in detail. Copyright © 2012 John Wiley & Sons, Ltd.

We report the synthesis, structural characterisation and solution-phase dynamics of a series of polyaromatic hydrocarbon complexes of the 12-electron {Rh(PiBu(3))(2)}(+) fragment. Crystal structures of this fragment with benzene, naphthalene, anthracene, pyrene, triphenylene and coronene are described, alongside their solution NMR spectroscopic data. The ligands map out a systematic increase in size of the aromatic subunit, and represent an approach to the limiting case of coordination to a graphene surface. The solid-state and solution structures of a {Rh(COD)}(+) fragment coordinated to a hexa-peri-hexabenzocoronene are also reported.

Construction of force field parameters of the oxyluciferin molecule on its electronic ground and excited states is presented. Several new approaches are introduced for more reliable parameterization: argon-scanning, Hessian matching, and constrained-group parameterization. The Ar-scanning approach is for fitting Lennard-Jones parameters so that the constructed force field can mimic the changes in ab initio energy of oxyluciferin-argon pair at various argon positions. The Hessian matching procedure is to closely reproduce the second derivative matrix of the bonded interaction terms of the force field functions, in comparison with the quantum chemically obtained results. The constrained-group algorithm is applied for both of these approaches to enable an automated atom-type-based parameterization. For complete description of the force field of the oxyluciferin molecule, we have also adopted the second order perturbatively corrected one-particle density matrices to obtain the atomic partial charges within the conventional framework of the restrained electrostatic potential fit. With the availability of the full force field parameter sets, the differences in condensed-phase dynamics on the two states can be investigated. As a simple demonstration, molecular dynamics simulations of aqueous oxyluciferin solution have been performed. The surrounding water structures for the two cases are analyzed by inspecting both the static solvent distribution functions as well as time variation of solvent–solute interaction. The contributions of charge–charge and dispersive interactions toward the solvation dynamics are also discussed. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010

Computational chemistry has been widely used to understand homogeneous reactions and to support spectroscopy analysis. Thus, it is a useful tool to understand gas-phase dynamics of metal organic chemical vapor deposition (MOCVD). In this study, we report that the basis set selection possibly results in unequivocal peak assignment in Raman spectroscopy, especially when an effective core potential (ECP) is employed. The basis set selection for the decompositionof dimethylcadmium (DMCd), for example, was examined using five different ECPs (i.e. CRENBS, CRENBL, SDD, LanL2DZ and SBKJC for Cd atom combined with STO-3G, 3-21G, 6-31G(d), 6-311G(d) and 6-311++G(2d,2p) for C and H atoms). The analyses demonstrated that the SDD/STO-3G/3-21G combination for Cd/C/H atoms best reproduce the experimentally reported CdC vibrational stretching modes of Cd(CH3)2 (DMCd) and •CdCH3 (MMCd). Although the SDD/STO-3G/3-21G combination consists of simple and basic basis sets, we found that a good potential balance between metal (Cd) and auxiliary (C) atoms is essential to estimate frequencies suitable for spectroscopy analysis computationally. The same combination of basis set was then used to examine other possible reaction steps, and Raman experiments successfully detected one of the suggested intermediates of (CdCH3)2. Copyright © 2009 John Wiley & Sons, Ltd.

The area fraction of tie molecules at the crystal–amorphous interface, amorphous phase dynamics, average crystal strength against stem sliding, and crack growth tortuosity concepts have been used simultaneously, for the first time, to develop a model for predicting the environmental stress cracking resistance of semicrystalline polymers. The model is based on the analogy of crack growth through the amorphous phase of semicrystalline polymers in a harsh environment at adhesive polymer–substrate interfaces. The model variable consists of the practical work of crack growth (Gc) times the crack growth path tortuosity (Γ) and correlates very well with the time to failure in the full notch creep test (FNCT) through a sigmoidal-type equation: FNCT = a{1 + exp[(b − GcΓ)/c]}−1, where a (3386), b (0.16), and c (0.006) are constants (r2 = 0.999). Gc is calculated by multiplication of the area fraction of tie molecules at the crystal–amorphous interface, the amorphous phase loss factor value at −25°C, and the sample storage shear modulus at the test temperature, whereas Γ is estimated as the product of the sample molecular weight and its distribution. The application of the Kendall rank correlation coefficient test as a primitive gross criterion of comparison among the proposed correlations also shows reasonable values of the rank correlation coefficient (0.891) and probability (0.000) for the new model. In other words, a point-to-point increasing or descending trend among the experimentally found data is ignored in comparison with the sound physical basis of the correlation toward the development of a comprehensive model. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

We hypothesized that, associated with the state of anaesthesia, characteristic changes exist in both cardio-respiratory and cerebral oscillator parameters and couplings, perhaps varying with depth of anaesthesia. Electrocardiograms (ECGs), respiration and electroencephalograms (EEGs) were recorded from two groups of 10 rats during the entire course of anaesthesia following the administration of a single bolus of ketamine–xylazine (KX group) or pentobarbital (PB group). The phase dynamics approach was then used to extract the instantaneous frequencies of heart beat, respiration and slow δ-waves (within 0.5–3.5 Hz). The amplitudes of δ- and θ-waves were analysed by use of a time–frequency representation of the EEG signal within 0.5–7.5 Hz obtained by wavelet transformation, using the Morlet mother wavelet. For the KX group, where slow δ-waves constituted the dominant spectral component, the Hilbert transform was applied to obtain the instantaneous δ-frequency. The θ-activity was spread over too wide a spectral range for its phase to be meaningfully defined. For both agents, we observed two distinct phases of anaesthesia, with a marked increase in θ-wave activity occurring on passage from a deeper phase of anaesthesia to a shallower one. In other respects, the effects of the two anaesthetics were very different. For KX anaesthesia, the two phases were separated by a marked change in all three instantaneous frequencies: stable, deep, anaesthesia with small frequency variability was followed by a sharp transition to shallow anaesthesia with large frequency variability, lasting until the animal awoke. The transition occurred 16–76 min after injection of the anaesthetic, with simultaneous reduction in the δ-wave amplitude. For PB anaesthesia, the two epochs were separated by the return of a positive response to the pinch test at 53–94 min, following which it took a further period of 45–70 min for the animal to awaken. δ-Waves were not apparent at any stage of PB anaesthesia. We applied non-linear dynamics and information theory to seek evidence of causal relationships between the cardiac, respiratory and slow δ-oscillations. We demonstrate that, for both groups, respiration drives the cardiac oscillator during deep anaesthesia. During shallow KX anaesthesia the direction either reverses, or the cardio-respiratory interaction becomes insignificant; in the deep phase, there is a unidirectional deterministic interaction of respiration with slow δ-oscillations. For PB anaesthesia, the cardio-respiratory interaction weakens during the second phase but, otherwise, there is no observable change in the interactions. We conclude that non-linear dynamics and information theory can be used to identify different stages of anaesthesia and the effects of different anaesthetics.

Disturbance may generate population bottlenecks by reducing population size and the number of founders establishing a new colony. We tested the hypothesis that the scale of disturbance affects the levels of genetic diversity and the spatial distribution of genotypes in naturally regenerating stands of Nothofagus dombeyi, an evergreen angiosperm tree, in northwestern Patagonia. At similar spatial scales, we predicted that old-growth stands characterized by fine-scale gap phase dynamics would be genetically diverse due to restricted gene flow among temporal and spatially isolated gaps. In contrast, young massively regenerated postfire cohorts resulting from coarse-scale disturbances would be genetically more homogeneous. At each of three paired old-growth and postfire stands a minimum of 50 trees were mapped and sampled within 1 ha. Fresh tissue was collected for isozyme analysis from a total of 361 trees along with tree cores and diameters. Tree age distributions reflected the dominant modes of regeneration. Six out of nine analysed loci were polymorphic. Mean genetic diversity parameters were greater but not significant in mature stands. Fixation indices suggested significant heterozygous deficit at two-thirds of possible tests indicating a Wahlund effect due to local recruitment of related seeds. F(ST) indicated moderate between-stand divergence. Mature stands concentrated half of positively like joins and yielded significant (P < 0.05) autocorrelation coefficients at small distance classes (< 20 m). Fine-scale patch dynamics within mature stands favours the maintenance of fine-scale genetic structure as a result of shade intolerance and local seed dispersal. Conversely, postfire stands suffer the effects of genetic drift given that a few reproductive trees produce a somewhat impoverished and genetically uniform progeny. Bottleneck effects will depend upon the density of remnant trees which could also be a function of the severity of fire.

Summary 1 Data from elevations ranging from mixed hardwood-conifer forest at 600 m to subalpine Abies balsamea forest at 1120 m indicate that canopy gaps are not static but expand over time due to mortality of trees at the gap margin and coalescence of gaps. Gap expansion is more frequent than gap initiation. Ultimately such disturbance patches may become more extensive than is normally considered as typical of gap-phase disturbance, but the processes of development are the same. 2 Disturbance agents involved in gap initiation tend to differ from those involved in gap expansion. Spruce beetle, dwarf mistletoe and most root diseases predominate as agents of gap initiation, while windthrow/windsnap, chronic wind stress and Armillaria root disease are important agents of gap expansion. 3 Concepts of equilibrium gap-phase dynamics and a shifting-mosaic steady state do not fully account for the dynamics of these spruce-fir forests. A spruce beetle outbreak in the late 1970s/early 1980s killed most of a cohort of dominant, emergent Picea rubens . This epidemic initiated a long-term cycle of disturbance and release that is likely to be repeated in many years when a new cohort of P. rubens becomes sufficiently large to sustain another major bark beetle outbreak. 4 Episodic disturbance agents affect long-lived, dominant species at infrequent but regular intervals (up to hundreds of years) and operate at the landscape level. Gap-phase cycles appear to be nested within the long-term cycle. Over the long term, episodic disturbance drives such ‘nested bicycle’ dynamics. 5 Spatial and temporal distribution of disturbance results not only from stochastic events such as storms, but also from host specificity of agents of disturbance, their tendency to attack certain age classes of trees, local and regional contagion, and susceptibility of trees at the edge of disturbance patches.

Summary 1 Few studies have addressed the mechanisms of coexistence of shade-tolerant and intolerant tree species in the canopy of old-growth, lowland rain forests of southern South America. We explored the hypothesis that their forest dynamics result from frequent, single tree-fall gap episodes. 2 We analysed the disturbance regime and assessed the regeneration modes of shadetolerant and intolerant canopy trees in a lowland, old growth North Patagonian rain forest in Chiloe Island (42 ° S) using dendroecological methods. 3 Dominant canopy trees were the shade-intolerant Nothofagus nitida (Fagaceae), Drimys winteri (Winteraceae) and the tolerant Podocarpus nubigena (Podocarpaceae). The oldest individuals, however, were represented by Saxegothaea conspicua , Podocarpaceae (shade tolerant > 498 years) and Weinmannia trichosperma , Cunoniaceae (intolerant > 382 years). Shade-tolerant species have regenerated continuously for the past 400 years, but recruitment of shade-intolerant species has increased only in the past 50 years. These regeneration patterns suggest a lack of catastrophic disturbance, at least since 1650. 4 Analysis of tree radial growth patterns revealed frequent moderate releases of both shade-tolerant and intolerant tree species, consistent with frequent small-scale disturbances, such as individual tree-fall gaps. Increased releases, peaking in 1940 and followed by enhanced recruitment, may be a consequence of individual tree-falls induced by lowintensity windstorms or limited selective logging. Such disturbances have occurred for at least 250 years, but have had little overall effect on stand structure and canopy composition. 5 The replacement and coexistence of shade-tolerant and intolerant tree species in the canopy of this North Patagonian forest can be explained by frequent small-scale disturbances (i.e. gap-phase dynamics) and by the absence of large-scale natural or anthropogenic disturbances over the past four centuries.

Aim Tropical rain forests are often regarded as pristine and undisturbed by humans. In Central Africa, community-wide disturbances by natural causes are rare and therefore current theory predicts that natural gap phase dynamics structure tree species composition and diversity. However, the dominant tree species in many African forests recruit poorly, despite the presence of gaps. To explain this, we studied the disturbance history of a species-rich and structurally complex rain forest. Location Lowland rain forest in Southern Cameroon. Methods We identified the recruitment conditions of trees in different diameter classes in 16 ha of species-rich and structurally complex old growth rain forest. For the identification of recruitment preference we used independent data on the species composition along a disturbance gradient, ranging from shifting cultivation fields (representing large-scale disturbance), to canopy gaps and old growth forest. Results In nine of sixteen 1-ha forest plots the older trees preferred shifting cultivation fields for recruitment while younger trees preferred gaps and closed forest conditions. This indicates that these nine sites once experienced large-scale disturbances. Three lines of evidence suggest that historical agricultural use is the most likely disturbance factor: (1) size of disturbed and undisturbed patches, (2) distribution of charcoal and (3) historical accounts of human population densities. Main conclusions Present-day tree species composition of a structurally complex and species-rich Central African rain forest still echoes historical disturbances, most probably caused by human land use between three to four centuries ago. Human impact on African rain forest is therefore, contrary to common belief, an issue not of the last decades only. Insights in historical use will help to get a more balanced view of the pristine rain forest, acknowledging that the dualism between old growth and secondary forest may be less clear than previously thought.

A new formalism of spectral filtering for the description of the modulation processes is proposed. The method allows one to study the classical problem of multi-phase modulations in dispersive systems. In the present paper, deep-water waves are considered. Spectral filtering results in a system of coupled equations that describe the modulations of the carrier wave and its harmonics. The formalism may find applications in a broad range of physical situations with multi-phase dynamics.

Summary We present computer simulations of the HIV infection based on a sophisticated cellular automata modelof the immune response. The infection progresses following the well known three-phase dynamics observed inpatients, that is, acute, silent and acquired immunodeficiency. Antigenic shift and selection of escape viral mutantswith low transcription rate explain the long term course of the asymptomatic phase, while the immunodeficiencystatus appears to be the consequence of a drastic reduction in T helper cell repertoire. Key words : cellular automata, computer simulation, human immunodeficiency virus, immune system. Introduction Immune system and HIV infection In recent years, all forms of immunodeficiency have beenovershadowed by the Acquired Immune Deficiency Syndrome(AIDS). This disease is caused by an infectious agent callhuman immunodeficiency virus, or HIV. 1 (There are twotypes of virus: HIV-1 and HIV-2. The former is much morecommon than the latter.)Among the features which make HIV very effective in itsaction against human beings, we recall: (i) its high replicationrate; (ii) high mutation rate; and (iii) the ability of a glyco-protein expressed on its surface (gp41) to bind the CD4

We develop a numerically exact approach to the quantum-phase and information-entropy dynamics of a molecular aggregate interacting with quantized fields. It is well known that a peculiar quantum nature, i.e., collapses and revivals, is observed in monomer and noninteracting aggregate models. In this article, we investigate the intermolecular interaction effects on the collapse-revival behavior using several dimer models (composed of two-state monomers with different intermolecular distances) interacting with a single-mode coherent photon field. The intermolecular interaction is taken into account by using the dipole-dipole interaction. Also, one- and two-exciton dimer models are considered in order to elucidate the exciton contributions to collapse-revival behavior. This quantum behavior is analyzed from the viewpoint of the dynamics of Pegg-Barnett photon-phase and information-entropy of dimers, which closely relate to the time evolution of quantum coherency between the ground and the excited dimer states and the degree of the entanglement between dimer and photon, respectively. It is found that the intermolecular interaction and the two-exciton generation provide remarkable changes in the collapse-revival behavior through their significant influence on the quantum-phase dynamics and the photon-dimer entanglement. From the dimer entropy dynamics, intermediate intermolecular interaction is found to cause the momentary decrease in the photon-dimer correlation in the early time region. This feature leads to the enhancement of off-diagonal density (quantum coherency) between two dimers. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 530-545, 2001

SUMMARY A numerical algorithm is used to study the ‘fan-spreading’ mechanism of axial particle turbulence acquisition and the effects on it of the inlet particle diameter distribution, downstream of a particle-laden, turbulent, round jet. The algorithm is based on the particle-source-in-cell numerical technique for two-phase flows. Eulerian equations are used for the description of the gas-phase dynamics, whilst the solid particles are treated within the Lagrangian framework. The turbulent particle dispersion is simulated with the aid of the stochastic separated flow model. It was found that the ‘fan-spreading’ turbulence is very much affected by the mean and standard deviation of the particle size distribution; in particular, it was found that the ‘fanspreading’ mechanism becomes weaker when the standard deviation of the particle diameter distribution is higher and the mean particle diameter smaller. An analytical expression describing the axial particle turbulence due to ‘fan-spreading’ is proposed and tested, along with a similarity profile valid for the particles of bigger size. KFY WORDS ‘Fan-spreading’ Particle turbulence Two-phase flow Turbulent jet Particle-laden jet Numerical study

Fragmentation alters forest canopy structure through various mechanisms, which in turn drive subsequent changes to biogeochemical processes and biological diversity. Using repeated airborne LiDAR (Light Detection and Ranging) mappings, we investigated the size distribution and dynamics of forest canopy gaps across a topical montane forest landscape in Hawaii naturally fragmented by lava >100 yr ago. The combined effects of long-term isolation were evaluated using edge-proximity patterns in the distribution of gaps identified in year 1 (“existing gaps”). In addition, using the data from year 2, we investigated patterns in the loss of canopy (“new gaps”) and regrowth of canopy (“filled gaps”). The size distributions of the three gap types were modelled using the power-law exponent, λ. We found that fragmentation has resulted in some large changes in gap dynamics, with both the total area of gaps and the relative proportion of large existing gaps increased with distance to fragment edge. In models of power-law distribution scaling, λ estimates decreased to asymptotic values within 20 m of fragment edges for existing gaps. The size distributions of new and filled gaps were surprisingly similar. However, the total area of filled gaps was less than that of new gaps, and this difference was greatest near fragment edges. From these results, we conclude that fragmentation may be capable of continuously altering gap-phase dynamics of a forest for more than a century.

Prediction of fluid phase dynamics in the vadose zone is hampered by the presence of different types of sharp interfaces, questioning the validity of standard theory that is based on assumption of continuity of air and water phases, uniform distribution of fluids in a control volume, local equilibrium of phase contents and pressures, and slow process velocities. Complexity of fluid front morphology and burst-like redistribution processes may be accentuated across material contrasts or at the interface between soil and atmosphere. This special section presents eleven contributions highlighting the role of interfaces on water and air distributions and outlining methods to improve prediction of interfacial displacement.

Multiscale expansion is a method appearing under different disguises in a variety of physical problems. The main components of the method can be defined as a local structure and an order parameter. The local structure, which is governed by underlying short-range equations, reproduces itself throughout an extended system while being smoothly modulated by one or more order parameters slowly varying on a long scale. The application of this method consists of the derivation of evolution equations governing the long-range behavior of order parameters. These equations are always incomparably simpler than the full set of underlying equations. This simplicity and universality is a major asset of the method, both practically and aesthetically. But most useful theoretical lessons are learned, perhaps, from those situations where the method breaks down and smooth long-range variation gives way to shock structures. This survey starts with an outline of the derivation of long-range equations. The classical problem of Taylor diffusion serves as an introductory example. It is followed by an analysis of generalized phase dynamics, which is the source of two basic long-range equations: the Burgers equation in a dissipative case and the Kuramoto-Sivashinsky equation in a weakly antidissipative case. We shall discuss the dynamics ofmore » shocks in these equations, which give, perhaps, the clearest demonstration of the phenomenon of intermittency. After reaching this double peak of universality we shall descend to other examples, supplied mostly by shallow-water theory, where the variety of long-range equations is multiplied by non-Newtonian effects and the presence of multiple order parameters. In these cases, the development of shocks is most prominent and long-range theory can be often retained only in the proximity of a bifurcation point.« less

A new method has been developed for the measurement of overall volumetric mass transfer coefficient (KLa) in gas-liquid-solid systems. This method is based on the examination of gas phase dynamics in a three-phase contactor and consists of measuring continuously the response of the outlet gas composition to a step input change of CO2 in the inlet gas stream. The advantages and limitations of the new method are presented and its sensitivity is discussed on the basis of model predictions. Preliminary results on the implementation of the CO2 method are also reported. Experimental data obtained in a nonviscous electrolyte solution show that the proposed method compares favorably with the conventional dissolved oxygen technique, provided that a correction is made to take account of the difference in diffusivity of oxygen and carbon dioxide.