Diversity of social ties in scientific collaboration networks

Diversity is one of the important perspectives to characterize behaviors of individuals in social networks. It is intuitively believed that diversity of social ties accounts for competition advantage and idea innovation. However, quantitative evidences in a real large social network can be rarely found in the previous research. Thanks to the availability of scientific publication records on WWW; now we can construct a large scientific collaboration network, which provides us a chance to gain insight into the diversity of relationships in a real social network through statistical analysis. In this article, we dedicate our efforts to perform empirical analysis on a scientific collaboration network extracted from DBLP, an online bibliographic database in computer science, in a systematical way, finding the following: distributions of diversity indices tend to decay in an exponential or Gaussian way; diversity indices are not trivially correlated to existing vertex importance measures; authors of diverse social ties tend to connect to each other and these authors are generally more competitive than others.     

Evolving model of weighted networks inspired by scientific collaboration networks

Inspired by scientific collaboration networks (SCN), especially our empirical analysis of econophysicists network, an evolutionary model for weighted networks is proposed. Besides a new vertex added in at every time step, old vertices can also attempt to build up new links, or to reconnect the existing links. The number of connections repeated between two nodes is converted into the weight of the link. This provides a natural way for the evolution of link weight. The path-dependent preferential attachment mechanism with local information is also introduced. It increases the clustering coefficient of the network significantly. The model shows the scale-free phenomena in degree and vertex weight distribution. It also gives well qualitatively consistent behavior with the empirical results.     

Third-order processes and their relation to structural symmetry

We have studied the various nonlinear optical processes that can be described by a fourth-rank ⁽³⁾-tensor: signals of frequency in degenerate four-wave mixing (DFWM), harmonics of frequency 2 and 3, and ⁽³⁾-type difference-frequency generation (DFG) with observation of anti-Stokes emission of a signal of frequency 2₁ — ₂. Structural information in terms of normalized anisotropies is derived in all frequency domains by analysis of the elements of the respective orientation-dependent susceptibility tensor. A novel laser-based technique for the remote orientation analysis of crystalline structures is introduced.     

Relativisticp-branes without constraints and their relation to the wiggly extended objects

The invariant evolution parameter is often used in the formulation of a so-called unconstrained relativistic quantum theoryof a point particle. Such a theory is very elegant, and contains the usual Klein-Gordon or the Dirac particle as a special case. In the present paper we extend the unconstrained theory to describe a continuous set of point particles forming a string or, in general, a membrane of arbitrary dimension p.The action of this system is not invariant with respect to reparametrizations of the evolution parameter and therefore there is no constraints among the dynamical variables, and no need for ghosts in the quantized theory. Then we show that such an unconstrained membrane is equivalent to a wiggly membranewhich has variable tension on its (p+1)-dimensional worldsheet. The equations of motion admit the usual well-known Dirac-Nambu-Goto membranes as particular solutions.On leave from J. Stefan Institute, University of Ljubljana, 61111 Ljubljana, Slovenia.     

Loop algebras and their relation to the conformal structure of integrable systems

We use the theorem of Kostant, Adler and Symes to construct an infinite set of local polynomials in involution with respect to the Poisson bracket realisation of the Neveu-Schwartz sector of the N=1 superconformal algebra.     

Plasmon resonances in nanoparticles,their applications to magnetics and relation to the Riemann hypothesis

The review of the mathematical treatment of plasmon resonances as an eigenvalue problem for specific boundary integral equations is presented and general properties of plasmon spectrum are outlined. Promising applications of plasmon resonances to magnetics are described. Interesting relation of eigenvalue treatment of plasmon resonances to the Riemann hypothesis is discussed.     

Superconformal algebras and their relation to integrable nonlinear systems

We relate the manifold of periodic functions on a circle with values in the Grassmann algebra to extended superconformal algebras. The graded Poisson brackets of these functions give the classical realization of the corresponding superconformal algebras and determine the hamiltonian structure for a class of integrable nonlinear equations. A super-generalization of the Korteweg-de Vries equation is found among these equations. In this way an important step in the program of the quantization of the Liouville equation is realized for the supersymmetric cases which are crucial in constructing a consistent quantum string theory. The construction of Miura transformations is outlined and the results for the N = 1,2 supersymmetric cases are presented.     

Reliability of distortion-product otoacoustic emissions and their relation to loudness

The reliability of distortion-product otoacoustic emission (DPOAE) measurements and their relation to loudness measurements was examined in 16 normal-hearing subjects and 58 subjects with hearing loss. The level of the distortion product (L(d)) was compared across two sessions and resulted in correlations that exceeded 0.90. The reliability of DPOAEs was less when parameters from nonlinear fits to the input/output (I/O) functions were compared across visits. Next, the relationship between DPOAE I/O parameters and the slope of the low-level portion of the categorical loudness scaling (CLS) function (soft slope) was assessed. Correlations of 0.65, 0.74, and 0.81 at 1, 2, and 4 kHz were observed between CLS soft slope and combined DPOAE parameters. Behavioral threshold had correlations of 0.82, 0.83, and 0.88 at 1, 2, and 4 kHz with CLS soft slope. Combining DPOAEs and behavioral threshold provided little additional information. Lastly, a multivariate approach utilizing the entire DPOAE I/O function was used to predict the CLS rating for each input level (dB SPL). Standard error of the estimate when using this method ranged from 2.4 to 3.0 categorical units (CU), suggesting that DPOAE I/O functions can predict CLS measures within the CU step size used in this study (5).     

Surface layers in general relativity and their relation to surface tensions

For a thin shell, the intrinsic 3-pressure will be shown to be analogous to -A, whereA is the classical surface tension: First, interior and exterior Schwarzschild solutions will be matched together such that the surface layer generated at the common boundary has no gravitational mass; then its intrinsic 3-pressure represents a surface tension fulfilling Kelvin's relation between mean curvature and pressure difference in the Newtonian limit. Second, after a suitable definition of mean curvature, the general relativistic analog to Kelvin's relation will be proven to be contained in the equation of motion of the surface layer.     

Patterns of interarticulator phasing and their relation to linguistic structure

Work by Tuller and Kelso [J. Acoust. Soc. Am. 76, 1030-1036 (1984)] and Kelso et al. [J. Phon. 14, 29-59 (1986)] has demonstrated stable relations between jaw and lip movements in (bV#CVb) utterances across rate and stress conditions. Specifically, the onset of lip movement toward the intervocalic consonant was found to be constant with respect to the vowel-to-vowel jaw cycle in both time and relative phasing. An attempt was made to replicate and extend this work by investigating interarticulator phase relations for utterances having a broader range of linguistic organization: In addition to rate and stress, syllable structure (open versus closed syllables) and identity of the intervocalic consonant (/p/ vs /m/) were manipulated. Results showed that the upper lip's lowering onset varied systematically with respect to the jaw vowel cycle as a function of both rate and stress. In addition, syllable structure and consonant identity influenced the relation of lip and jaw gestures. There was a general tendency for any condition that shortened the first vowel to produce earlier onsets of the upper lip relative to the jaw. However, the within-condition jaw cycle duration variability did not correlate with the within-condition variability in phase. Thus it seems that stable interarticulator phase relations maintain not only the integrity of phonological structure, as suggested by Kelso et al., but structural integrity at other levels of linguistic organization as well.     

Photophysical properties of coumarins in relation to the nature of their third and seventh substituents

The spectral, luminescent, and lasing properties of four derivatives of 7-hydroxycoumarin: 7-hydroxy-3-(4-methylthiazolyl)-coumarin (CI), 3-(4-methylthiazolyl)-2-oxocoumarin-furan-2-carboxylate (CII), 3-(4-(benzo[1,3]dioxolyl)-thiazolyl)-2-oxocoumarin-furan-2-carboxylate (CIII), and 3-(4-(benzo[1,3]dioxolyl)-thiazolyl)-2-hydroxycoumarin (CIV), as well as of their protolytic forms, are studied experimentally and theoretically by the INDO/S method. The luminescence quantum yield of the CIII and CIV compounds, having bulky substituents at position 3, is shown to strongly depend on the polarity of a solvent. It is suggested that, in polar solvents, these substituents are displaced out of the plane of the skeleton of the electronically excited molecule. The quantum-chemical calculations of such structures confirmed their weak fluorescence ability due to intense intersystem crossing. The lasing ability of the protolytic forms of the compounds considered is studied. The reason for the absence of lasing for the neutral compounds is discussed.     

Topological relation of layered complex networks

We present analytically the relation functions between degrees or clustering coefficients of a common station in both space L layer and space P layer of transportation systems. A good agreement between the analytical results and the empirical investigations in a railway system and three bus systems in China is observed.     

Semantic networks based on titles of scientific papers

In this paper we study the topological structure of semantic networks based on titles of papers published in scientific journals. It discusses its properties and presents some reflections on how the use of social and complex network models can contribute to the diffusion of knowledge. The proposed method presented here is applied to scientific journals where the titles of papers are in English or in Portuguese. We show that the topology of studied semantic networks are small-world and scale-free.     

Relativistic corrections to carbon atom energy levels and their relation to the singlet-triplet splitting in methylene

The relativistic correction to the s ² p ²-sp ³ excitation energy in the carbon atom is shown to be 120 cm^-1 rather than 500 cm^-1 as reported by Desclaux et al. This is too small to explain the 8 kJ mol^-1 discrepancy between theory and experiment for the ¹ A ₁-³ B ₁ energy separation in methylene.

Two pitfalls that can arise when calculating relativistic corrections from approximate wavefunctions are discussed.     

Weighted networks of scientific communication: the measurement and topological role of weight

In order to take the weight of connection into consideration and to find a natural measurement of weight, we have collected papers in Econophysics and constructed a network of scientific communication to integrate idea transportation among econophysicists by collaboration, citation and personal discussion. Some basic statistics such as weight per degree are discussed in Fan et al. J. Mod. Phys. B (17–19) (2004) 2505. In this paper, by including the papers published recently, further statistical results for the network are reported. Clustering coefficient of weighted networks is introduced and empirically studied in this network. We also compare the typical statistics on this network under different weight assignments, including random and inverse weight. The conclusion from weight-redistributed network is helpful to the investigation of the topological role of weight.     

Neutron resonances in 45Sc and their relation to thermal scattering parameters

The total neutron cross section of ⁴⁵Sc from 400 eV to 22 keV has been measured. The results are shown to be incompatible with the postulate that a J = 4 bound state dominates thermal scattering.