Range Correlations Research Articles

Die Erfassung von Suizidwünschen: Erste psychometrische Befunde zur deutschen Version des Interpersonal Needs Questionnaire (INQ)

The Interpersonal Needs Questionnaire (INQ) assesses desire for suicide according to the Interpersonal Theory of Suicide. Psychometric properties of the German version of the INQ are investigated. The INQ was applied in a sample of 281 undergraduate students to investigate dimensionality, reliability and validity. The 2-factorial structure of the original version was confirmed for the German version of the INQ in this sample. The subscales "Perceived Burdensomeness" (α = 0.88) and "Thwarted Belongingness" (α = 0.83) show very good internal consistencies. Both subscales show medium range correlations with depressiveness. There are significantly higher levels of "Perceived Burdensomeness" and "Thwarted Belongingness" in participants with current suicidal ideation or prior suicidal or self-injuring behaviour. These findings show that the German version of the INQ has good psychometric properties. Further research is needed to replicate these findings in clinical samples, and to test the utility of the INQ in predicting and preventing suicidal behaviour in patients at risk.

Upscaling Lévy motions in porous media with long range correlations

Bacterial motility has been modeled by Lévy motions which were upscaled in porous media, with drift processes such as Lévy processes and time-changed Brownian motion, via central limit theorems. It was possible to prove the limit theorems and upscale the processes because of the independence of their increments. Therefore, it has not been applied to processes with correlated increments such as fractional Brownian motions. In this paper, the upscaling approach is generalized to porous media with long-range correlated processes. The processes are modeled by a fractional Brownian velocity process and p-diffusive position processes that were defined and used to classify diffusion processes by O’Malley and Cushman [“A renormalization group classification of nonstationary and/or infinite second moment diffusive processes,” J. Stat. Phys. 146, 989–1000 (2012)]10.1007/s10955-012-0448-3. A few examples of p-diffusive processes are discussed by computing the values of the parameter p.

Nuclear and partonic dynamics in the EMC effect

It has been recently confirmed that the magnitude of the EMC effect measured in electron deep inelastic scattering is linearly related to the Short Range Correlation scaling factor obtained from electron inclusive scattering. By using a $x$-rescaling approach we are able to understand the interplay between the quark-gluon and hadronic degrees of freedom in the discussion of the EMC effect.

Solid-State NMR Approaches to Internal Dynamics of Proteins: From Picoseconds to Microseconds and Seconds

Solid-state nuclear magnetic resonance (NMR) spectroscopy has matured to the point that it is possible to determine the structure of proteins in immobilized states, such as within microcrystals or embedded in membranes. Currently, researchers continue to develop and apply NMR techniques that can deliver site-resolved dynamic information toward the goal of understanding protein function at the atomic scale. As a widely-used, natural approach, researchers have mostly measured longitudinal (T1) relaxation times, which, like in solution-state NMR, are sensitive to picosecond and nanosecond motions, and motionally averaged dipolar couplings, which provide an integral amplitude of all motions with a correlation time of up to a few microseconds. While overall Brownian tumbling in solution mostly precludes access to slower internal dynamics, dedicated solid-state NMR approaches are now emerging as powerful new options. In this Account, we give an overview of the classes of solid-state NMR experiments that have expanded the accessible range correlation times from microseconds to many milliseconds. The measurement of relaxation times in the rotating frame, T1ρ, now allows researchers to access the microsecond range. Using our recent theoretical work, researchers can now quantitatively analyze this data to distinguish relaxation due to chemical-shift anisotropy (CSA) from that due to dipole-dipole couplings. Off-resonance irradiation allows researchers to extend the frequency range of such experiments. We have built multidimensional analogues of T2-type or line shape experiments using variants of the dipolar-chemical shift correlation (DIPSHIFT) experiment that are particularly suited to extract intermediate time scale motions in the millisecond range. In addition, we have continuously improved variants of exchange experiments, mostly relying on the recoupling of anisotropic interactions to address ultraslow motions in the ms to s ranges. The NH dipolar coupling offers a useful probe of local dynamics, especially with proton-depleted samples that suppress the adverse effect of strong proton dipolar couplings. We demonstrate how these techniques have provided a concise picture of the internal dynamics in a popular model system, the SH3 domain of α-spectrin. T1-based methods have shown that large-amplitude bond orientation fluctuations in the picosecond range and slower 10 ns low-amplitude motions coexist in these structures. When we include T1ρ data, we observe that many residues undergo low amplitude motions slower than 100 ns. On the millisecond to second scale, mostly localized but potentially cooperative motions occur. Comparing different exchange experiments, we found that terminal NH2 groups in side chains can even undergo a combination of ultraslow large-angle two-site jumps accompanied by small-angle fluctuations that occur 10 times more quickly.

Long range correlation in earthquake precursory signals

Research on earthquake prediction has drawn serious attention of the geophysicist, geologist and investigators in different fields of science across the globe for many decades. Researchers around the world are actively working on recording pre-earthquake changes in non-seismic parameters through a variety of methods that include anomalous changes in geochemical parameters of the Earth’s crust, geophysical properties of the lithosphere as well as ionosphere etc. Several works also have been done in India to detect earthquake precursor signals using geochemical and geophysical methods. However, very few works have been done so far in India in this field through the application of nonlinear techniques to the recorded geophysical and geochemical precursory signals for earthquakes. The present paper deals with a short review of the early works on geochemical precursors that have been carried out in India as yet. With a view to detect earthquake precursory signals by means of gas-geochemical method we developed a network of seismo-geochemical monitoring observatories in India in hot springs and mud volcano crater. In the last few years we detected several geochemical anomalies and those were observed prior to some major earthquakes that occurred within a radius of 1500 km from the test sites. In the present paper we have applied nonlinear techniques to the long term, real-time and natural data sets of radon-222 and associated gamma originated out of the terrestrial degassing process of the earth. The results reveal a clear signature of the long range correlation present in the geochemical time series. This approach appears to be a potential tool to explore intrinsic information hidden within the earthquake precursory signals.

Information transfer of an Ising model on a brain network

We consider an anatomical connectivity matrix (66 nodes), obtained via diffusion spectrum imaging (DSI) and white matter tractography [1], describing the brain at a coarse scale, and implement on it an Ising model with Glauber dynamics, estimating the transfer of information between spins. Tuning the temperature to criticality, so as to render the system characterized by long range correlations, we find that the critical state is characterized by the maximal amount of total information transfer among variables and exhibits signature of the law of diminishing marginal returns, a fundamental principle of economics which states that when the amount of a variable resource is increased, while other resources are kept fixed, the resulting change in the output will eventually diminish [2]. The origin of such behavior resides in the structural constraint related to the fact that each node of the network may handle a limited amount of information. The modulation of this phenomenon is analyzed evaluating, at each node, the ratio R between the outgoing and the incoming information. It turns out that R is related to (but not fully explained by) the in-strength of the brain network: nodes with high R are those more prone to became bottlenecks as the information transfer increases. The regions which are recognized as potential bottlenecks by the present analysis are symmetrical in the two hemisphere, and are Superior Frontal Cortex, Precuneus, Superior Temporal Cortex, Medial and Lateral Orbitofrontal Cortex. Some of these regions are considered as hubs both for the structural and for the functional connectome. Furthermore the temperature of the Ising model has an influences on the ratio between intra-hemispheric and inter-hemispheric information transfer, which grows with the temperature, though not uniformly.

Hydrophobic force, a Casimir-like effect due to hydrogen-bond fluctuations

Hydrophobic force, interfacial tension, and transverse density profile in a confined water system are addressed from first principles of statistical mechanics in a lattice model for water. Using the molecular mean field theory technique we deduce explicit expressions for each of the above mentioned phenomena and show that hydrophobic force is a manifestation of a Casimir-like effect due to hydrogen-bond fluctuations in confined water. It is largely influenced by the long range correlations of orientational fluctuations. Furthermore, the temperature dependence of hydrophobic force between large non-polar surfaces is suggested to be different from that between small solutes. The mechanisms contributing to characteristic behavior in each case are identified. In the case of large surfaces, the prevalence of discrete fluctuation modes in the confinement direction and their entropic contribution to the overall free energy dominate the temperature dependence. Mode discretization is also implicated in the variation of interfacial tension with separation distance between confining surfaces and characteristic density profile of the confined fluid. All the computations are parameter free and compare favorably with results of molecular dynamics simulations and experiments.

Effect of long-range correlated disorder on the transverse localization of light in 1D array of optical waveguides

In this paper, the effects of the long-range correlated diagonal disordered optical waveguide arrays in the presence and absence of the positive Kerr nonlinearity are analyzed numerically. The calculated inverse localization length shows that the long-range correlation in a disordered system causes a decrease in the transverse localization in linear optical waveguide arrays. In the presence of positive Kerr nonlinearity, the inverse localization length is increased by increasing the nonlinear parameters in long-range correlated disordered systems in comparison with the uniform distribution disordered systems. This means that the long range correlation causes an enhancement of transverse localization in nonlinear waveguides in contrast with linear waveguide arrays. The calculated participation ratio and effective beamwidth confirm these results for linear and nonlinear systems.

Comparative Spectral Analysis and Correlation Properties of Observed and Simulated Total Column Ozone Records

We present a statistical analysis of total column ozone records obtained from satellite measurements and from two global climate chemistry models on global scale. Firstly, a spectral weight analysis is performed where the relative strength of semiannual, annual and quasi-biennial oscillations are determined with respect to the integrated power spectra. The comparison reveals some anomalies in the model representations at each spectral component. The tails of the spectra demonstrate that both models underestimate high frequency (daily) ozone variability, which might have a complex origin, since several dynamical processes affect short time changes of the ozone level at a given location. Secondly, detrended fluctuation analysis is exploited to analyze two-point correlations of anomaly time series. Both models reproduce the characteristic geographic dependence of correlation strength over the overlapping area with empirical observations (latitude band between 60°S and 60°N). The values of precise correlation exponents are hard to obtain over regions where quasi-biennial oscillations or other strong nonstationarities (ozone hole) are present. In spite of all the numerical difficulties, significant long range correlations are detected for total ozone over all geographic locations.

Description of the Tautomerism in Some Azonaphthols

The performance of several functionals (M06‐2X, B97D, ωB97 family and B2PLYPD), accounting long range correlation, was evaluated in respect of the tautomerism of 1‐phenylazo‐4‐naphthol. Three sets of experimental data were used to define the evaluation criteria: reproduction of the bond lengths in the structures of the individual tautomers, description of the non‐planarity of the enol tautomer and prediction of the position of the tautomeric equilibrium (∆G value) at 298 K. The results show that M06‐2X at most of the basis sets reasonably covers all requirements. In most of the cases, the empirical dispersion correction tends to stabilize the keto tautomer independently on the basis set.The obtained results have been used to select M06‐2X, ωB97X and B2PLYP functionals to test their performance for a set of azonaphthols (1‐phenylazo‐4‐napthol, 1‐phenylazo‐2‐naphthol and 2‐phenylazo‐1‐naphthol) where experimental data for the Gibbs free energies at room temperature are available. As a result, it should be pointed out the M06‐2X functional slightly overestimates the enol tautomer, but at 6‐31G**, TZVP and def2TZVP basis sets, the deviation is below 0.5 kcal.mol−1. The same result, but in favor of the keto tautomer, is obtained at B2PLYP/D95++**. Copyright © 2013 John Wiley & Sons, Ltd.

Self-Organized Criticality: Emergent Complex Behavior in PM10 Pollution

We analyze long-term time series of daily average PM10 concentrations in Chengdu city. Detrended fluctuation analysis of the time series shows long range correlation at one-year temporal scale. Spectral analysis of the time series indicates 1/f noise behavior. The probability distribution functions of PM10 concentrations fluctuation have a scale-invariant structure. Why do the complex structures of PM10 concentrations evolution exhibit scale-invariant? We consider that these complex dynamical characteristics can be recognized as the footprint of self-organized criticality (SOC). Based on the theory of self-organized criticality, a simplified sandpile model for PM10 pollution with a nondimensional formalism is put forward. Our model can give a good prediction of scale-invariant in PM10 evolution. A qualitative explanation of the complex dynamics observed in PM10 evolution is suggested. The work supports the proposal that PM10 evolution acts as a SOC process on calm weather. New theory suggests one way to understand the origin of complex dynamical characteristics in PM10 pollution.

Elastic Electron Scattering from Some Light Nuclei

The effects of the two-body short range correlation (SRC) and the occupation probability (�) of higher states on the elastic electron scattering longitudinal form factors F(q) are investigated. Considering the effect of higher occupation probabilities and the effect of SRCs is important in getting a good agreement between the calculated elastic longitudinal electron scattering F(q)s and those of the experimental data for 4 He, 12 C, 16 O, 28 Si, 32 S, and 40 Ca nuclei.

Evolution of sympatric species: a case study of the coral reef fish genus Pomacanthus (Pomacanthidae)

AbstractAimTo establish a spatial and temporal framework within which we can begin to investigate the role of geography in the evolution of Pomacanthus species. This study examines the phylogenetic relationships among Pomacanthus species, tests whether the degree of sympatry among sister taxa correlates with their age, and explores potential modes of diversification.LocationPan‐tropical coral reef systems.MethodsThree gene regions (12S rRNA, 16S rRNA and nuclear S7) from all 13 Pomacanthus species were used in conjunction with fossil calibration to reconstruct a chronogram. IUCN maps were used to evaluate geographical range overlap. Various age–range correlation (ARC) analyses were used to test for a correlation between range overlap and node age. Range‐size symmetry and node age were also examined.ResultsBiogeographical splits within the phylogeny corroborated key biogeographical events well, suggesting a potential role for allopatric speciation in the evolutionary history of the genus. ARC analyses suggested that speciation leading to sympatry is widespread in Pomacanthus, with 80% of sister species showing complete or substantial (> 85%) range overlap. No significant relationship between degree of sympatry and node age was recovered, which demonstrates that, for this group, exceptional sympatry is not necessarily a result of relatively old lineages. Range‐size symmetry analysis was consistent with models of peripatric speciation within a finite area.Main conclusionsWe present evidence consistent with allopatric speciation, while our ARC results are consistent with simulations of sympatric speciation, with the possibility of peripheral budding having led to the richness of sympatric species in the West Indian Ocean. We discuss how these processes can affect the interpretation of temporal and spatial analyses, and provide a basis for future investigations into the processes driving speciation.

Production Mechanism of Pion and Kaon in S + Pb Reaction at 200 GeV/c

The correlation data for identical pions and kaons produced in S+Pb collisions at 200 GeV/c by NA44 Experiment are analysed by theoretical formulae with the long range correlation. It is found that interaction range (the root mean square (rms)) of K−K− is smaller than that of K+K+: Rrms (K−K−) ≈ (5.2 ~ 6 fm) < Rrms(K+K+) ≈ (7 ∼ 7.5 fm). This suggests that in nuclear collisions the anti u-quarks are produced in smaller space region than the u-quarks. Moreover, formulae of the Coulomb wave function correction are presented. The corrections to data of pions and kaons are also discussed, to confirm the above results.

The structure of liquid GeSe revisited: A first principles molecular dynamics study

Early first-principles molecular dynamics results on liquid GeSe were characterized by shortcomings in the description of Ge-Ge (and to a lesser extent Se-Se) short range correlations. In that case the exchange-correlation functional adopted was the one devised by Perdew and Wang (PW91). In the search of improvements in the atomic-scale modelling of this liquid, we have produced new sets of data by employing two different schemes for the exchange-correlation part within the density functional theory approach. The two functionals selected are those proposed by Becke, Lee, Yang, and Parr (BLYP) and by Perdew, Burke, and Ernzerhof (PBE). The PBE results turned out to be quite similar to the PW91 ones. The BLYP results feature instead a better account of the Ge-Ge first shell of neighbors, correctly exhibiting two clear maxima separated by a deep minimum. Due to the increase in the number of the tetrahedral structural units, the atomic mobility of Ge and Se atoms in the network is reduced with respect to the PW91 case. This brings the diffusion coefficients of the two species down to values close to those of liquid Ge2Se3 and liquid GeSe2.

Densification of the packing structure under vibrations

Two packing structures with the maximum packing densities of 0.64 and 0.74 for the amorphous state and crystalline state, respectively, were numerically reproduced in the packing densification of equal spheres subjected to onedimensional and three-dimensional vibrations using the discrete element method (DEM), and the results were physically validated. These two packing structures were analyzed in terms of coordination number (CN), radial distribution function (RDF), angular distribution function (ADF), and pore size distribution (Voronoi/Delaunay tessellation). It is shown that CN distributions have the peak values of 7 and 12 for the amorphous state and crystalline state, respectively. RDF and ADF distributions show isolated peaks and orientation preferences for the crystalline state, indicating the long range and angle correlation among particles commonly observed in the crystalline state. Voronoi/Delaunay tessellation also shows smaller and narrower pore size distribution for the crystalline state.

On quenched and annealed critical curves of random pinning model with finite range correlations

This paper focuses on directed polymers pinned at a disordered and correlated interface. We assume that the disorder sequence is a q-order moving average and show that the critical curve of the annealed model can be expressed in terms of the Perron-Frobenius eigenvalue of an explicit transfer matrix, which generalizes the annealed bound of the critical curve for i.i.d. disorder. We provide explicit values of the annealed critical curve for $q=1$, 2 and a weak disorder asymptotic in the general case. Following the renewal theory approach of pinning, the processes arising in the study of the annealed model are particular Markov renewal processes. We consider the intersection of two replicas of this process to prove a result of disorder irrelevance (i.e. quenched and annealed critical curves as well as exponents coincide) via the method of second moment.

Strong convergence to the homogenized limit of elliptic equations with random coefficients II

Consider a discrete uniformly elliptic divergence form equation on the $d$ dimensional lattice $\Z^d$ with random coefficients. In [3] rate of convergence results in homogenization and estimates on the difference between the averaged Green's function and the homogenized Green's function for random environments which satisfy a Poincar\'{e} inequality were obtained. Here these results are extended to certain environments with long range correlations. These environments are simply related via a convolution to environments which do satisfy a Poincar\'{e} inequality.

Magneto-optical effect in GdN epitaxial thin film

We report the cooperative phenomena of magneto-optical effect in AlN/GdN/AlN heterostructure grown by reactive rf magnetron sputtering technique performed under a base pressure less than 5×10−6 Pa. The ultra-high vacuum conditions during growth of GdN enable to curtail the oxophilicity character. The temperature dependent optical absorbance measurements have been carried out to evaluate the direct optical band gaps at the X point through the Tauc plots for the heterostructure. We observed for the first time that the optical absorbance studies demonstrate an exceptional splitting in valance and conduction bands in GdN below the critical temperature. The splitting energy is slightly increased with increase of temperature range of 30–55 K and the difference is merely ΔE=28 meV. Furthermore, the splitting energy drastically increases from 30 K to 3 K and the difference is ΔE=102 meV. This startling increase convincing that there is rapid increase of magnetic moments caused by long range correlation of spins.

Long range correlations in tree ring chronologies of the USA: Variation within and across species

AbstractTree ring width data are among the best proxies for reconstructing past temperature and precipitation records. The discovery of fractal scaling and long‐memory in meteorological and hydrological signals motivates us to investigate such properties in tree ring chronologies. Detrended fluctuation analysis and adaptive fractal analysis are utilized to estimate the Hurst parameter values of 697 tree ring chronologies from the continental United States. We find significant differences in the Hurst parameter values across the 10 species studied in the work. The long‐range scaling relations found here suggest that the behavior of tree ring growth observed in a short calibration period may be similar to the general behavior of tree ring growth in a much longer period, and therefore, the limited calibration period may be more useful than originally thought. The variations of the long‐range correlations within and across species may be further explored in future to better reconstruct paleoclimatic records.