Solar-neutrino variations: A manifestation of nonzero neutrino mass and magnetic moment, and mixing

Time variations of solar neutrino flux are investigated on the basis of available Homestake experimental data for more than two solar cycles (1970–1994). At first, we determine (with the weight-time function by taking into account ³⁷Ar decay), for each solar neutrino run n, the effective Earth’s heliolatitude L _eff(n), the effective Zurich sunspots number Z _eff(n), the effective latitude of sunspots distribution Λ_eff(n), and the effective surfaces of sunspots in different heliolatitude belts. Then, we consider the correlation of solar-electron-neutrino fluxes with these parameters for different periods of solar activity. It is found that correlation coefficients change sign in different periods of solar activity, so that for total period 1970–1994 the correlation coefficient is very small. The obtained information indicates that a neutrino should have nonzero mass and nonzero magnetic moment.     

Dynamic behavior of non-uniform granular gases system with the fractal characteristic in one dimension

A one-dimensional dynamic model of polydisperse granular mixture with a power-law size distribution is presented, in which the particles are subject to inelastic mutual collisions and driven by Gaussian white noise. The particle size distribution of the mixture has the fractal characteristic, and a fractal dimension D as a measurement of the inhomogeneity of the particle size distribution is introduced. We define the global granular temperature and the kinetic pressure of the mixture, and obtain their expressions. By molecular dynamics simulations, we have mainly investigated how the inhomogeneity of the particle size distribution and the inelasticity of collisions influence the steady-state dynamic properties of the system, focusing on the global granular temperature, kinetic pressure, velocity distribution and distribution of interparticle spacing. Some novel results are found that, with the increase of the fractal dimension D, the global granular temperature and the kinetic pressure decrease, the velocity distribution deviates more obviously from the Gaussian one and the particles cluster more pronouncedly at the same value of the restitution coefficient e (0<e<1). On the other hand, as the restitution coefficient e decreases, the dynamic behavior has the similar evolution as above at the fixed fractal dimension D. The dynamic behavior changing with e and D is, respectively, presented.     

Dynamic compensation temperature in the mixed spin-1 and spin-2 Ising model in an oscillating field on alternate layers of a hexagonal lattice

The dynamic behavior of a mixed spin-1 and spin-2 Ising system with a crystal-field interaction in the presence of a time-dependent oscillating external magnetic field on a hexagonal lattice is studied by using the Glauber-type stochastic dynamics. The lattice is formed by alternate layers of spins σ=1$\sigma =1$ and S=2. The Hamiltonian model includes intersublattice, intrasublattice and crystal-field interactions. The set of mean-field dynamic equations is obtained by employing the Glauber transition rates. Firstly, we study time variations of the average sublattice magnetizations in order to find the phases in the system, and the thermal behavior of the average sublattice magnetizations in a period or the dynamic sublattice magnetizations to obtain the dynamic phase transition points as well as to characterize the nature (continuous and discontinuous) of transitions. Then, the behavior of the dynamic total magnetization as a function of the temperature is investigated to find the dynamic compensation points as well as determine the type of behavior. We also present the dynamic phase diagrams for both presence and absence of the dynamic compensation temperatures in the nine different planes. According to the values of Hamiltonian parameters, besides the paramagnetic (p), antiferromagnetic (af), ferrimagnetic (i) and non-magnetic (nm) fundamental phases, eight different mixed phases and the compensation temperature or L- and N-types behavior in the Néel classification nomenclature exist in the system.     

Solar activity at present and in the near future

We discuss the current solar cycle (number 24), its unusual characteristics, and the forthcoming solar maximum. We predict the solar activity over the next few decades. A prolonged solar minimum is expected, and the maximum of cycle 24 is predicted to have a low number of sunspots (annual mean number of sunspots, R _z ≈ 50).     

Global wolf numbers

A new (global) series of Wolf numbers (W _G ), which takes all the sunspots on the Sun??s surface, including the spots that are invisible from the Earth, into account, is proposed for consideration with the aim of obtaining a more complete characteristic of solar activity. The optimum configuration of spacecraft for this purpose is examined.     

Multi-grid Monte Carlo via XY embedding. General theory and two-dimensional O(N)-symmetric non-linear σ-models

We introduce a variant of the multi-grid Monte Carlo (MGMC) method, based on the embedding of an XY model into the target model, and we study its mathematical properties for a variety of non-linear σ-models. We then apply the method to the two-dimensional O(N)-symmetric nonlinear σ-models (also called N-vector models) with N = 3,4,8 and study its dynamic critical behavior. Using lattices up to 256 × 256, we find dynamic critical exponentsZ_int, M² 0.70 ± 0.08, 0.60 ± 0.07, 0.52 ± 0.10 for N = 3, 4, 8, respectively (subjective 68% confidence intervals). Thus, for these asymptotically free models, critical slowing down is greatly reduced compared to local algorithms, but not completely eliminated; and the dynamic critical exponent does apparently vary with N. We also analyze the static data for N = 8 using a finite-size scaling extrapolation method. The correlation length ξ agrees with the four-loop asymptotic-freedom prediction to within 1 % over the interval 12 ⪅ ξ ⪅ 650.     

Dynamic compensation temperature in the kinetic spin-1 Ising model in an oscillating external magnetic field on alternate layers of a hexagonal lattice

The dynamic behavior of a two-sublattice spin-1 Ising model with a crystal-field interaction (D) in the presence of a time-varying magnetic field on a hexagonal lattice is studied by using the Glauber-type stochastic dynamics. The lattice is formed by alternate layers of spins σ=1 and S=1. For this spin arrangement, any spin at one lattice site has two nearest-neighbor spins on the same sublattice, and four on the other sublattice. The intersublattice interaction is antiferromagnetic. We employ the Glauber transition rates to construct the mean-field dynamical equations. Firstly, we study time variations of the average magnetizations in order to find the phases in the system, and the temperature dependence of the average magnetizations in a period, which is also called the dynamic magnetizations, to obtain the dynamic phase transition (DPT) points as well as to characterize the nature (continuous and discontinuous) of transitions. Then, the behavior of the total dynamic magnetization as a function of the temperature is investigated to find the types of the compensation behavior. Dynamic phase diagrams are calculated for both DPT points and dynamic compensation effect. Phase diagrams contain the paramagnetic (p) and antiferromagnetic (af) phases, the p+af and nm+p mixed phases, nm is the non-magnetic phase, and the compensation temperature or the L-type behavior that strongly depend on the interaction parameters. For D<2.835 and H₀>3.8275, H₀ is the magnetic field amplitude, the compensation effect does not appear in the system.     

Nonlinear dynamics of domain walls with a vortex internal structure in magnetouniaxial films with planar anisotropy

The nonlinear and generally unsteady dynamics of domain walls with a vortex internal structure in a constant magnetic field H is investigated on the basis of the numerical solution of the Landau-Lifshitz equation for a 2D distribution of magnetization M in magnetic films with planar anisotropy taking into account exactly the main interaction, including the dipole-dipole interaction. It is shown that in addition to field H _c (bifurcation field) above which the motion of a wall becomes unsteady and its internal structure experiences global dynamic changes, there exists a field H₀ separating two steady motions of the wall with different structures. The data clarifying the physical origin of the nonlinear dynamic rearrangement of the wall structure are presented. New rearrangement mechanisms associated with the generation and attenuation of vortices as well as their tunneling through the central surface of the wall are established. The existence of subperiod oscillations of the wall velocity in a static field in addition to the oscillations associated with the precession of M around the easy magnetization axis is predicted. The period T of dynamic variations of the wall structure is studied, and an empirical formula is proposed for describing the singular behavior of the T(H) dependence near H=H _Hc with the critical index depending on the film parameters. The bifurcation process is studied, and a nonlinear dependence of the critical field H _c on the film thickness and the saturation magnetization is established. The possibility of direct experimental investigation of the dynamic rearrangement of the internal structure of the wall is indicated.     

Dynamic magnetic hysteresis behavior and dynamic phase transition in the spin-1 Blume-Capel model

The nature (time variation) of response magnetization m(wt) of the spin-1 Blume-Capel model in the presence of a periodically varying external magnetic field h(wt) is studied by employing the effective-field theory (EFT) with correlations as well as the Glauber-type stochastic dynamics. We determine the time variations of m(wt) and h(wt) for various temperatures, and investigate the dynamic magnetic hysteresis behavior. We also investigate the temperature dependence of the dynamic magnetization, hysteresis loop area and correlation near the transition point in order to characterize the nature (first- or second-order) of the dynamic transitions as well as obtain the dynamic phase transition temperatures. The hysteresis loops are obtained for different reduced temperatures and we find that the areas of the loops are decreasing with the increasing of the reduced temperatures. We also present the dynamic phase diagrams and compare the results of the EFT with the results of the dynamic mean-field approximation. The phase diagrams exhibit many dynamic critical points, such as tricritical (•), zero-temperature critical (Z), triple (TP) and multicritical (A) points. According to values of Hamiltonian parameters, besides the paramagnetic (P), ferromagnetic (F) fundamental phases, one coexistence or mixed phase region, (F+P) and the reentrant behavior exist in the system. The results are in good agreement with some experimental and theoretical results.     

Growing networks with preferential deletion and addition of edges

A preferential attachment model for a growing network incorporating the deletion of edges is studied and the expected asymptotic degree distribution is analyzed. At each time step t=1,2,…, with probability π₁>0 a new vertex with one edge attached to it is added to the network and the edge is connected to an existing vertex chosen proportionally to its degree, with probability π₂ a vertex is chosen proportionally to its degree and an edge is added between this vertex and a randomly chosen other vertex, and with probability π₃=1−π₁−π₂<1/2 a vertex is chosen proportionally to its degree and a random edge of this vertex is deleted. The model is intended to capture a situation where high-degree vertices are more dynamic than low-degree vertices in the sense that their connections tend to be changing. A recursion formula is derived for the expected asymptotic fraction p_k of vertices with degree k, and solving this recursion reveals that, for π₃<1/3, we have p_k∼k^{−(3−7π₃)/(1−3π₃)}, while, for π₃>1/3, the fraction p_k decays exponentially at rate (π₁+π₂)/2π₃. There is hence a non-trivial upper bound for how much deletion the network can incorporate without losing the power-law behavior of the degree distribution. The analytical results are supported by simulations.     

Effects of dynamic response time in an evolving market

Considering the time scales of global information and personal reaction, we study the role of dynamic response time in the evolution of collective behavior in an evolving market. The insensitiveness to the market information makes the population cluster around a kind of extreme behavior, in which they always follow what happened last time, while a sensitive population tends to self-segregate into opposing groups. The average success rate R among all the agents is found to have a nonmonotonic dependence on the time scale parameter q. There exists a critical value below (above) which R decreases (increases) with the rise of q. Theoretical analyses demonstrate that the higher efficiency found in the market with an insensitive population is related to its predictability. In such a predictable market, the agents following current prediction have a higher winning probability than those rejecting it. Analytical calculations are in good agreement with numerical data.     

Trading model with pair pattern strategies

A simple trading model based on pair pattern strategy space with holding periods is proposed. Power-law behavior is observed for the return variance σ², the price impact H and the predictability K for both models, with linear and square root impact functions. The sum of the traders’ wealth displays a positive value for the model with a square root price impact function, and a qualitative explanation is given based on the observation of the conditional excess demand 〈A|u〉. The cumulative wealth distribution also obeys a power-law behavior with an exponent close to that of real markets. An evolutionary trading model is further proposed. The elimination mechanism effectively changes the behavior of traders, and a power-law behavior is observed in the measure of zero return distribution P(r=0). The trading model with other types of traders, e.g., traders with the MG’s strategies and producers, are also carefully studied.     

Observation of hydrogen and helium satellites in a turbulent plasma

Time-resolved measurements of satellites about the (1s2s?1s3d) forbidden transition in helium, satellites both of the H_δ line of hydrogen and of its splittings and, finally, satellites of He II 4868 Å have been observed. The behavior of these satellites is correlated relative to each other and to previously reported satellites both on H_β and near the 6632 Å (1s2p?1s3p) forbidden transition in helium. The appearance of the satellites is attributed to a strong field interaction between orthogonal components of the dynamic and quasistatic electric fields generated in a plasma by an instability.     

Size distribution of magnetic iron oxide nanoparticles using Warren–Averbach XRD analysis

We use the Fourier transform based Warren–Averbach (WA) analysis to separate the contributions of X-ray diffraction (XRD) profile broadening due to crystallite size and microstrain for magnetic iron oxide nanoparticles. The profile shape of the column length distribution, obtained from WA analysis, is used to analyze the shape of the magnetic iron oxide nanoparticles. From the column length distribution, the crystallite size and its distribution are estimated for these nanoparticles which are compared with size distribution obtained from dynamic light scattering measurements. The crystallite size and size distribution of crystallites obtained from WA analysis are explained based on the experimental parameters employed in preparation of these magnetic iron oxide nanoparticles. The variation of volume weighted diameter (D_v, from WA analysis) with saturation magnetization (M_s) fits well to a core shell model wherein it is known that M_s=M_bulk(1?6g/D_v) with M_bulk as bulk magnetization of iron oxide and g as magnetic shell disorder thickness.     

Superfunctions for amplifiers

An amplifier is characterized by its transfer function T, which expresses the dependence of the output signal on the input signal. This signal may be related to power, intensity, energy of a pulse, or its fluence, or any similar physical quantity. The internal structure of the amplified signal (e.g., its spectral content, polarization, temporal behavior, and spatial distribution) is not taken into account. The amplifier is considered to be spatially homogeneous and uniformly pumped. The transfer function is supposed to be known (measured in an experiment). The problem of reconstruction of the behavior of the signal inside the amplifier is formulated. For a given transfer function T, the evolution of the signal inside is interpreted as the superfunction F, satisfying the transfer equation F(z + 1) T(F(z)), where z is of coordinate along the propagation direction, while the length of the amplifier is used as a unit of measurement. (For simplicity, distances are measured in units of the length of the amplifier.) Two examples of realistic transfer function T are considered; they correspond to amplification of continuous wave and to amplification of pulses. In these examples, the transfer function and the distribution of the signal along the amplifier can be expressed in terms of special functions. The iterative procedure is suggested as a general method of reconstructing the signal along the amplifier, if neither the transfer function T, nor the superfunction F can be expressed with a simple combination of special functions. The examples show that the iterations converge to a physically meaningful solution. This method is expected to be useful for the characterization of laser materials from the measurement of the transfer function of a bulk sample.     

Tracking moving magnetic features in the photosphere

This research aims for an objective identification, tracking, and a statistical analysis of the Moving Magnetic Features (MMFs) around sunspots using SOHO/MDI high-resolution magnetograms. To this end, we develop a computerized tracking program and study the motion and magnetism of the outflows of MMFs around 26 sunspots. Our method locates 4–27 MMFs per hour, with higher counts for large sunspots. We differentiate MMFs into type α that have a polarity opposite to the parent sunspots, and type β that share the sunspot’s polarity. These sunspots’ MMF subsets exhibit a wide range of central tendencies which have distinctive correlations with the sunspots. In general, α-MMFs emerge farther from the sunspot, carry less flux, and move faster than β-MMFs. The typical α/β-MMFs emerge at 2.2–8.1/0.1–3.2 Mm outside the penumbra limb, with lifetimes of 1.1–3.1/1.3–2.0 h. They are 1.1–6.6/1.4–3.6 Mm² in area and carry 1.4–12.5/4.8–11.4 ×10¹⁸ Mx of flux. They travel a distance of 2.7–5.9/2.8–3.6 Mm with the speed of 0.5–0.9/0.4–0.7 km/s. Compared to the α-MMFs produced by large sunspots, those of small spots are smaller. They emerge closer to sunspot, move farther, live longer, and carry less flux. β-MMFs show much less correlation with the sunspots. The flux outflow carried by the MMFs ranges from 0.2 to 8.3 × 10¹⁹Mx· h⁻¹ and does not show obvious correlation with the sunspots’ evolution. The frequency distributions of the MMFs’ distance traveled, area, and flux are exponential. This suggests the existence of numerous small, weak, and short-timescale magnetic objects which might contribute to the sunspot flux outflow.     

Emergence of the self-similar property in gene expression dynamics

Many theoretical models have recently been proposed to understand the structure of cellular systems composed of various types of elements (e.g., proteins, metabolites and genes) and their interactions. However, the cell is a highly dynamic system with thousands of functional elements fluctuating across temporal states. Therefore, structural analysis alone is not sufficient to reproduce the cell's observed behavior.In this article, we analyze the gene expression dynamics (i.e., how the amount of mRNA molecules in cell fluctuate in time) by using a new constructive approach, which reveals a symmetry embedded in gene expression fluctuations and characterizes the dynamical equation of gene expression (i.e., a specific stochastic differential equation). First, by using experimental data of human and yeast gene expression time series, we found a symmetry in short-time transition probability from time t to time t+1. We call it self-similarity symmetry (i.e., the gene expression short-time fluctuations contain a repeating pattern of smaller and smaller parts that are like the whole, but different in size). Secondly, we reconstruct the global behavior of the observed distribution of gene expression (i.e., scaling-law) and the local behavior of the power-law tail of this distribution. This approach may represent a step forward toward an integrated image of the basic elements of the whole cell.     

Complex motion in nonlinear-map model of elevators in energy-saving traffic

We have studied the dynamic behavior and dynamic transitions of elevators in a system for reducing energy consumption. We present a nonlinear-map model for the dynamics of M elevators. The motion of elevators depends on the loading parameter and their number M. The dependence of the fixed points on the loading parameter is derived. The dynamic transitions occur at 2(M−1) stages with increasing the value of loading parameter. At the dynamic transition point, the motion of elevators changes from a stable state to an unstable state and vice versa. The elevators display periodic motions with various periods in the unstable state. In the unstable state, the number of riding passengers fluctuates in a complex manner over various trips.     

Novel hybrid nanostructured materials of magnetite nanoparticles and pectin

A novel hybrid nanostructured material comprising superparamagnetic magnetite nanoparticles (MNPs) and pectin was synthesized by crosslinking with Ca²⁺ ions to form spherical calcium pectinate nanostructures, referred as MCPs, which were typically found to be 100-150 nm in size in dried condition, confirmed from transmission electron microscopy and scanning electron microscopy. The uniform size distribution was revealed from dynamic light scattering measurement. In aqueous medium the MCPs showed swelling behavior with an average size of 400 nm. A mechanism of formation of spherical MCPs is outlined constituting a MNP-pectin interface encapsulated by calcium pectinate at the periphery, by using an array of characterization techniques like zeta potential, thermogravimetry, Fourier transformed infrared and X-ray photoelectron spectroscopy. The MCPs were stable in simulated gastrointestinal fluid and ensured minimal loss of magnetic material. They exhibited superparamagnetic behavior, confirmed from zero field cooled and field cooled profiles and showed high saturation magnetization (M_s) of 46.21 emu/g at 2.5 T and 300 K. M_s decreased with increasing precursor pectin concentrations, attributed to quenching of magnetic moments by formation of a magnetic dead layer on the MNPs.     

Dynamic phase transitions and dynamic phase diagrams in the kinetic spin-5/2 Blume-Capel model in an oscillating external magnetic field: Effective-field theory and the Glauber-type stochastic dynamics approach

Using an effective field theory with correlations, we study a kinetic spin-5/2 Blume-Capel model with bilinear exchange interaction and single-ion crystal field on a square lattice. The effective-field dynamic equation is derived by employing the Glauber transition rates. First, the phases in the kinetic system are obtained by solving this dynamic equation. Then, the thermal behavior of the dynamic magnetization, the hysteresis loop area and correlation are investigated in order to characterize the nature of the dynamic transitions and to obtain dynamic phase transition temperatures. Finally, we present the phase diagrams in two planes, namely (T/zJ, h₀/zJ) and (T/zJ, D/zJ), where T absolute temperature, h₀, the amplitude of the oscillating field, D, crystal field interaction or single-ion anisotropy constant and z denotes the nearest-neighbor sites of the central site. The phase diagrams exhibit four fundamental phases and ten mixed phases which are composed of binary, ternary and tetrad combination of fundamental phases, depending on the crystal field interaction parameter. Moreover, the phase diagrams contain a dynamic tricritical point (T), a double critical end point (B), a multicritical point (A) and zero-temperature critical point (Z).