The State of Self-Organized Criticality of the Sun During the Last Three Solar Cycles. II. Theoretical Model

The observed powerlaw distributions of solar flare parameters can be interpreted in terms of a nonlinear dissipative system in the state of self-organized criticality (SOC). We present a universal analytical model of a SOC process that is governed by three conditions: (i) a multiplicative or exponential growth phase, (ii) a randomly interrupted termination of the growth phase, and (iii) a linear decay phase. This basic concept approximately reproduces the observed frequency distributions. We generalize it to a randomized exponential-growth model, which includes also a (log-normal) distribution of threshold energies before the instability starts, as well as randomized decay times, which can reproduce both the observed occurrence frequency distributions and the scatter of correlated parametyers more realistically. With this analytical model we can efficiently perform Monte-Carlo simulations of frequency distributions and parameter correlations of SOC processes, which are simpler and faster than the iterative simulations of cellular automaton models. Solar cycle modulations of the powerlaw slopes of flare frequency distributions can be used to diagnose the thresholds and growth rates of magnetic instabilities responsible for solar flares.Comment: Part II of Paper I: The State of Self-Organized Criticality of the Sun During the Last Three Solar Cycles. I. Observation

Mapping language to the world: the role of iconicity in the sign language input

Most research on the mechanisms underlying referential mapping has assumed that learning occurs in ostensive contexts, where label and referent co-occur, and that form and meaning are linked by arbitrary convention alone. In the present study, we focus on iconicity in language, that is, resemblance relationships between form and meaning, and on non-ostensive contexts, where label and referent do not co-occur. We approach the question of language learning from the perspective of the language input. Specifically, we look at child-directed language (CDL) in British Sign Language (BSL), a language rich in iconicity due to the affordances of the visual modality. We ask whether child-directed signing exploits iconicity in the language by highlighting the similarity mapping between form and referent. We find that CDL modifications occur more often with iconic signs than with non-iconic signs. Crucially, for iconic signs, modifications are more frequent in non-ostensive contexts than in ostensive contexts. Furthermore, we find that pointing dominates in ostensive contexts, and suggest that caregivers adjust the semiotic resources recruited in CDL to context. These findings offer first evidence for a role of iconicity in the language input and suggest that iconicity may be involved in referential mapping and language learning, particularly in non-ostensive contexts

Delocalized, non-SUSY pp-branes, tachyon condensation and tachyon matter

We construct non-supersymmetric $p$-brane solutions of type II supergravities in arbitrary dimensions ($d$) delocalized in one of the spatial transverse directions. By a Wick rotation we convert these solutions into Euclidean $p$-branes delocalized in the transverse time-like direction. The former solutions in $d=10$ nicely interpolate between the $(p+1)$-dimensional non-BPS D-branes and the $p$-dimensional BPS D-branes very similar to the picture of tachyon condensation for the tachyonic kink solution on the non-BPS D-branes. On the other hand the latter solutions interpolate between the $(p+1)$-dimensional non-BPS D-branes and the tachyon matter supergravity configuration very similar to the picture of rolling tachyon on the non-BPS D-branes.Comment: 15 pages, typos correcte

Controllable Degradable Plasma Electrolytic Oxidation Coated Mg Alloy for Biomedical Application

A controllable degradable coating on Mg alloy based on plasma electrolytic oxidation (PEO) process is reported for the first time. The reported results show that introduction of silica nanoparticles into PEO electrolytes leads to their reactive incorporation in coatings and thus influencing the degradation behavior. Dissolution of amorphous phases facilitates chemical reaction with components of simulated body fluid, resulting in self-healing effect via redeposition of insoluble conversion products. The dynamic balance between dissolution of the original coating and reconstruction of corrosion layer is mainly determined by the phase composition of the coating as well as the surrounding corrosive medium

Attribution of climate change, vegetation restoration, and engineering measures to the reduction of suspended sediment in the Kejie catchment, southwest China

10.5194/hess-18-1979-2014Hydrology and Earth System Sciences1851979-199

Azimuthal asymmetries in lepton-pair production at a fixed-target experiment using the LHC beams (AFTER)

A multi-purpose fixed-target experiment using the proton and lead-ion beams of the LHC was recently proposed by Brodsky, Fleuret, Hadjidakis and Lansberg, and here we concentrate our study on some issues related to the spin physics part of this project (referred to as AFTER). We study the nucleon spin structure through $pp$ and $pd$ processes with a fixed-target experiment using the LHC proton beams, for the kinematical region with 7 TeV proton beams at the energy in center-of-mass frame of two nucleons $\sqrt{s}=115$ GeV. We calculate and estimate the $\cos2\phi$ azimuthal asymmetries of unpolarized $pp$ and $pd$ dilepton production processes in the Drell--Yan continuum region and at the $Z$-pole. We also calculate the $\sin(2\phi-\phi_S)$, $\sin(2\phi+\phi_S)$ and $\sin2\phi$ azimuthal asymmetries of $pp$ and $pd$ dilepton production processes with the target proton and deuteron longitudinally or transversally polarized in the Drell--Yan continuum region and around $Z$ resonances region. We conclude that it is feasible to measure these azimuthal asymmetries, consequently the three-dimensional or transverse momentum dependent parton distribution functions (3dPDFs or TMDs), at this new AFTER facility.Comment: 15 pages, 40 figures. Version accepted for publication in EPJ

Ruling out the Modified Chaplygin Gas Cosmologies

The Modified Chaplygin Gas (MCG) model belongs to the class of a unified models of dark energy (DE) and dark matter (DM). It is characterized by an equation of state (EoS) $p_c = B\rho - A/\rho^{\alpha}$, where the case $B=0$ corresponds to the Generalized Chaplygin Gas (GCG) model. Using a perturbative analysis and power spectrum observational data we show that the MCG model is not a sucessful candidate for the cosmic medium unless $B=0$. In this case, it reduces to the usual GCG model.Comment: Latex file, 7 pages, 6 figures in eps forma

MICROFRACTURE OF HUMAN THORACOLUMBAR VERTEBRAL BODY UNDER FATIGUE LOADING

The purpose of this study was to investigate the relationship between lumbar vertebral microfracture and fatigue loading on young human spine under physiological cyclic compression loads. Thirty-three thoracolumbar vertebrae (T12 to L4) were obtained from 7 adult Chinese male cadavers. They were randomly divided into 5 groups. Cyclical compression was performed for 20,000 cycles with 2 Hz. Load magnitude was determined respectively as 10%, 20% and 30% of the ultimate compressive load. Four cylindrical sections were obtained from each vertebra and the cross-sectional slides were made. The histomorphometry was used to determine microfracture densitiy and distribution. No fracture was detected in the radiographs of groups III, IV and V after fatigue load. Microfracture density in the cyclic compression group increased from 0.46 #/mm2 in Group III to 0.66 #/mm2 (Group IV) and 0.94 #/mm2 (Group V) under different loading levels (). These results provide evidence for the existence of microfractures caused by fatigue loads that are undetectable by X-ray

EFFECTS OF REHABILITATION ON BACK MUSCLE CONTRACTION PATTERNS OF LOW BACK PAIN PATIENTS

The aims of this study were to conduct a comparative investigation of muscle function between low back pain (LBP) patients and normal subjects, as well as to explore whether intensive rehabilitation can change back muscle contraction synergy. 20 normal subjects and 20 patients with chronic LBP were asked to perform symmetrical and asymmetrical tasks. LBP patients were tested in the weeks immediately before and after 12-week LBP rehabilitation treatment. Tasks include “carrying” weights up and down with a 45° left rotation. Eight channel surface EMG electrodes were placed on the surface of paraspinal muscles. correlation between right and left corresponding muscles as well as between pre- and post-treatment were calculated. Lifting capacity for LBP patients were also measured before and after treatment. EMG profiles showed that the muscle activity strategies varied between normal subjects and LBP patients. The correlation coefficients for spinal muscles have shown very reproducible intra-subject muscle contraction synergies. Unbalanced EMG patterns found in LBP patients under symmetrical tasks were not affected by rehabilitation treatment

Weighted azimuthal asymmetries in a diquark spectator model

We analytically calculate weighted azimuthal asymmetries in semi-inclusive lepton-nucleon deep-inelastic scattering and Drell-Yan processes, using transverse-momentum-dependent partonic densities obtained in a diquark spectator model. We compare the asymmetries with available preliminary experimental data, in particular for the Collins and the Sivers effect. We make predictions for other cases of interest in running and planned experiments.Comment: 21 pages, 13 (multiple) figures in eps format, RevTeX