Properties Of Spectrum Research Articles

Efficient non-degenerate two-photon excitation for fluorescence microscopy.

Non-degenerate two-photon excitation (ND-TPE) has been explored in two-photon excitation microscopy. However, a systematic study of the efficiency of ND-TPE to guide the selection of fluorophore excitation wavelengths is missing. We measured the relative non-degenerate two-photon absorption cross-section (ND-TPACS) of several commonly used fluorophores (two fluorescent proteins and three small-molecule dyes) and generated 2-dimensional ND-TPACS spectra. We observed that the shape of a ND-TPACS spectrum follows that of the corresponding degenerate two-photon absorption cross-section (D-TPACS) spectrum, but is higher in magnitude. We found that the observed enhancements are higher than theoretical predictions.

Spectrum of anomalous dimensions in hypercubic theories

We compute the spectrum of anomalous dimensions of non-derivative composite operators with an arbitrary number of fields $n$ in the $O(N)$ vector model with cubic anisotropy at the one-loop order in the $\epsilon$-expansion. The complete closed-form expression for the anomalous dimensions of the operators which do not undergo mixing effects is derived and the structure of the general solution to the mixing problem is outlined. As examples, the full explicit solution for operators with up to $n=6$ fields is presented and a sample of the OPE coefficients is calculated. The main features of the spectrum are described, including an interesting pattern pointing to the deeper structure.

Density and tracer statistics in compressible turbulence: Phase transition to multifractality.

We study the statistics of fluid (gas) density and concentration of passive tracer particles (dust) in compressible turbulence. As Ma increases from small or moderate values, the density and the concentration in the inertial range go through a phase transition from a finite continuous smooth distribution to a singular multifractal spatial distribution. Multifractality is associated with scaling, which would not hold if the solenoidal and the potential components of the flow scaled differently, producing transport which is not self-similar. Thus, we propose that the transition occurs when the difference of the scaling exponents of the components, decreasing with Ma, becomes small. Under the smallness assumption, the particles' volumes obey a power-law evolution. That, by the use of conservation of the total volume of the flow, entails the volumes' shrinking to zero with probability 1 and formation of a singular distribution. We discuss various concepts of multifractality and propose a way to calculate fractal dimensions from numerical or experimental data. We derive a simple expression for the spectrum of fractal dimensions of isothermal turbulence and describe limitations of lognormality. The expression depends on a single parameter: the scaling exponent of the density spectrum. We demonstrate that the pair-correlation function of the tracer concentration has the Markov property. This implies applicability of the compressible version of the Kraichnan turbulence model. We use the model to derive an explicit expression for the tracer pair correlation that demonstrates their smooth transition to multifractality and confirms the transition's mechanism. The obtained fractal dimension explains previous numerical observations. Our results have potentially important implications for astrophysical problems such as star formation as well as technological applications such as supersonic combustion. As an example, we demonstrate the strong increase of planetesimal formation rate at the transition. We prove that finiteness of internal energy implies vanishing of the sum of Lyapunov exponents in the dissipation range. Our study leads to the question of whether the fluid density which is an active field that reacts back on the transporting flow and the passive concentration of tracers must coincide in the steady state. This is demonstrated to be crucial both theoretically and experimentally. The fields' coincidence is provable at small Mach numbers; however, at finite Mach numbers, the assumption of mixing is needed, which we demonstrate to be not self-evident because of the possibility of self-organization.

Hereditarily just infinite profinite groups with complete Hausdorff dimension spectrum

We prove that the inverse limits of certain iterated wreath products in product action have complete Hausdorff dimension spectrum with respect to their unique maximal filtration of open normal subgroups. Moreover we can produce explicitly subgroups with a specified Hausdorff dimension.

Non-motor symptoms in Parkinson's disease: An explorative network study

Research on the association between non-motor symptoms (NMS) of Parkinson's disease (PD) and patients' quality of life (QoL) has given insight into the burden of NMS. Most studies investigate NMS by assessing the contribution of individual symptoms to QoL. However, symptoms could also have an interactive relationship, which might not be fully taken into account when only studying these individual contributions. Recently, a network approach has been developed that treats symptoms as nodes and associations between symptoms as edges in a network, providing the opportunity to investigate the dimensional spectrum of NMS. In the current cross-sectional study, we investigated NMS with both approaches: first, we assessed individual contributions of NMS to QoL. Second, we aimed to assess NMS using a network approach. Seventy PD patients completed questionnaires on NMS and QoL. Our primary analysis shows that the domains Mood and Pain are significant contributors to QoL. Our secondary network analysis suggests that Mood and Sleep play central roles in the NMS-network, and that Mood and Cognition are strongly related. Because of power issues, the generalizability of our explorative results is limited. However, complementary information from the network analysis does suggest that focusing on sleep problems might help both mood and pain symptoms, which negatively affect QoL. Investigating symptoms not only as individual and independent entities but rather as part of a connected network could show how treating one symptom affects other symptoms.

On the scaling behaviour of the alternating spin chain

In this note we report the results of our study of a 1D integrable spin chain whose critical behaviour is governed by a CFT possessing a continuous spectrum of scaling dimensions. It is argued that the computation of the density of Bethe states of the continuous theory can be reduced to the calculation of the connection coefficients for a certain class of differential equations whose monodromy properties are similar to those of the conventional confluent hypergeometric equation. The finite size corrections to the scaling are also discussed.

The dimension spectrum of conformal graph directed Markov systems

In this paper we study the dimension spectrum of general conformal graph directed Markov systems modeled by countable state symbolic subshifts of finite type. We perform a comprehensive study of the dimension spectrum addressing questions regarding its size and topological structure. As a corollary we prove that the dimension spectrum of infinite conformal iterated function systems is compact and perfect. On the way we revisit the role of the parameter \(\theta \) in graph directed Markov systems and we show that new phenomena arise. We also establish topological pressure estimates for subsystems in the abstract setting of symbolic dynamics with countable alphabets. These estimates play a crucial role in our proofs regarding the dimension spectrum, and they allow us to study Hausdorff dimension asymptotics for subsystems. Finally, we narrow our focus to the dimension spectrum of conformal iterated function systems and we prove, among other things, that the iterated function system resulting from the complex continued fractions algorithm has full dimension spectrum. As a result, we provide a positive answer to the Texan conjecture for complex continued fractions.

Impact of seismic-type shock parameters on the soil-structure interaction effect in the USC mining region

The paper deals with seismic-type surface and building vibrations randomly occurring as a result of rockbursts in mining regions (random events as with earthquakes). The focus is on the problem of ground vibrations transmission to building foundation – it is one of very important phenomenon associated with soil-structure interaction effect. One of the ways of estimation of possible differences between simultaneously developing free-field vibrations next to a building and building foundation vibrations, i.e. using a ratio of response spectra (RRS), is applied to this study. Analysis concerns the ratio of dimensionless and dimensional acceleration response spectra (β and Sa) – denoted as RRS(β) and RRS(Sa), respectively. Horizontal vibrations parallel to the transverse (x) and longitudinal (y) axis of the representative (typical) two-storey, masonry office building are discussed. Calculations are based on the results of in situ surface vibration measurements performed in the seismically active Upper Silesian Coalfield (USC) mining area in Poland (long-term, full-scale monitoring). Evaluation of the dependence of the curves of ratio of response spectra on some parameters corresponding to mine-induced vibrations (i.e. epicentral distance, mining shock energy, peak value of free-field vibrations) is executed. From the obtained results, it can be definitely concluded that the influence of the most important mining tremor parameters (i.e. epicentral distance, mining shock energy, peak value of free-field vibrations) on the ratio of response spectra calculated in the successive ranges of these parameters, is clearly observed.

Multifractal features of spatial variation in construction land in Beijing (1985\u20132015)

Over the last 30 years, Beijing has experienced rapid development. The city’s spatial pattern and changes are extremely complicated. Therefore, to reveal the spatial patterns at different scales and levels, the construction land in Beijing within the 6th ring road in 1985, 1999, 2008, and 2015, was analyzed using global and local multifractal analyses. The global analysis shows that, over the past 30 years, the development of new construction land in this region experienced a process that transformed it from being a hierarchical spatial structure with a low-evolution intensity (1985) to being a spatial structure with a higher evolution intensity and multi-scale differential development (1999, 2008) with a hierarchical spatial system (one main urban area with a number of satellite towns) (2015). Local analysis further shows that the spatial pattern of the construction land in this region tended to be simplified over the past 30 years. The construction land in this region displays specific evolutionary characteristics with the increase in breadth (q) and intensity (Dq) and a multifractal dimension spectrum (f(a) – a(q)) and dominant spectrum at various spatial scales over a four-year period. In general, the influence of high-density areas on the spatial pattern of the construction land is decreasing, while the influence of low-density areas is increasing. Based on this, this paper also summarizes the theoretical value of multifractal analysis in economic geography research, highlighting its advantages, limitations, and application range, and presents the technical analysis process and other suggestions for future research.

Using the Binary Transformation for the Characterization of Structure-Texture Boundaries of Mineral Multifractal Surfaces

The possibilities of using fractal analysis for detecting atypical areas on digital images of feldspar (cracks, kinks, adhesions and structural changes) are investigated. The selection of texture heterogeneities and morphological features is carried out using the field of fractal dimension D, the self-similarity coefficient field K, and the measure field SRGB (triangle areas in the coordinate system of properties). The influences of the displacement step as well as the size of the scanning “window” are estimated. The proposed segmentation of digital images of minerals allows one to eliminate the regions with different ranges of fractal measure values and to describe complex multifractal surfaces of minerals taking into account the spectrum of fractal dimensions, because such fractals, along with geometric features, possess certain statistical properties. The application of the binary transformation of the obtained fractal measure fields to the selected threshold value revealed a sensitivity to a quantitative and qualitative description of the complexity of structural and texture boundaries of the surface. This fact which can be used to predict the results of the ores crushing.

Spatial–Spectral Regularized Local Scaling Cut for Dimensionality Reduction in Hyperspectral Image Classification

Dimensionality reduction (DR) methods have attracted extensive attention to provide discriminative information and reduce the computational burden of the hyperspectral image (HSI) classification. However, the DR methods face many challenges due to limited training samples with high dimensional spectra. To address this issue, a graph-based spatial and spectral regularized local scaling cut (SSRLSC) for DR of HSI data is proposed. The underlying idea of the proposed method is to utilize the information from both the spectral and spatial domains to achieve better classification accuracy than its spectral domain counterpart. In SSRLSC, a guided filter is initially used to smoothen and homogenize the pixels of the HSI data in order to preserve the pixel consistency. This is followed by generation of between-class and within-class dissimilarity matrices in both spectral and spatial domains by regularized local scaling cut (RLSC) and neighboring pixel local scaling cut (NPLSC) respectively. Finally, we obtain the projection matrix by optimizing the updated spatial-spectral between-class and total-class dissimilarity. The effectiveness of the proposed DR algorithm is illustrated with two popular real-world HSI datasets.

Looking into Service Representation Tools through the Multidimensional Nature of Service Experience

Despite the recognized importance of service experience as a unit of analysis and an object of design in the service design field, studies that analyse and compare service representation tools against the nature of multidimensional service experience are still limited. This paper investigates multidimensional service experience by reviewing up-to-date scholarly debates of the topic, and identifies three experience dimensions and 12 associated attributes. Based on the finding, an analytic framework is proposed as an instrument to assess service representation tools. This framework is used to discern three service representation tools’ relative positions in a holistic spectrum of service experience dimensions.

Similarity measure method based on spectra subspace and locally linear embedding algorithm

Due to the high dimensionality, redundancy, noise and nonlinearity of the near infrared (NIR) spectra data result the difficulty of the similarity measure. This paper presented a similarity measure method SSLLE based on the spectra subspace and locally linear embedding (LLE) algorithm. Firstly, we divided the high dimensional spectra data into several subspaces according to the absorption band of the major chemical compositions, which effectively avoids the influence of irrelevant features and noise and reduces the dimension and computation complexity of the LLE. Then, we modified the LLE algorithm by introducing the geodesic distance instead of Euclidean distance, which solves the measure problem of the Euclidean distance in high dimensional space. In order to make the sample more evenly distributed, the method of distance calculation in LLE was also modified. For each spectra subspace, the distance matrix was calculated according to the embedding that was mapped from the high dimensional space by using the modified LLE. Subsequently, the spectral similarity matrix of the sample set was integrated by adding all of the individual distance matrices of each subspace so that the sample with the highest similarity can be found.In order to investigate the effectiveness of the algorithm, the spectral projection of the samples was analyzed first, the results showed that the SSLLE distinguished the tobacco samples from different areas significantly better than the methods of principal component analysis (PCA) and LLE. Secondly, we compared the results of searching the most spectrally similar sample with the target tobacco, it showed that the SSLLE had the minimum differences in the chemical composition, and the highest consistency with the recommendation of the experts than that of PCA and LLE algorithm. It also had good robustness and precision.

Local and anisotropic strain in AlN film on sapphire observed by Raman scattering spectroscopy

Strain states in face-to-face-annealed sputter-deposited c-plane AlN (FFA-sp-AlN) films on c- and a-plane sapphire substrates were evaluated. As a result, an existence of anisotropic strain in the c-plane FFA-sp-AlN film on a-plane sapphire was ascertained by X-ray diffraction reciprocal space maps. Consequently, the peak splitting of polarized Raman spectra was observed from the c-plane FFA-sp-AlN film on a-plane sapphire for the first time. Meanwhile, there was no peak splitting of polarized Raman spectra of the c-plane FFA-sp-AlN film on c-plane sapphire, which has anisotropic strain. In addition, local and anisotropic strain relaxations in patterned FFA-sp-AlN films on c-plane sapphires were experimentally proven by polarized Raman spectra and two dimensional Raman spectra maps.

Radar target detection method based on cross‐correlation singularity power spectrum

Recently, radar target detection based on fractal theory has received great attention. Especially in the sea clutter background, fractal modelling, fractal dimension, and multifractal spectrum are widely used in radar signal processing. Here, a novel target detection method based on cross-correlation singularity power spectrum (CSPS) is proposed. Firstly, the CSPS theory and algorithm is derived based on SPS; secondly, based on the SPS and CSPS analysis of radar sea clutter, radar target detection parameters are designed, and the detection flow and algorithm based on the CSPS method is presented in detail. The proposed methodology is tested on sea clutter, both with and without targets, from the Ice Multi-parameter Imaging X -Band radar data set. The simulation results indicate that the proposed method performs better than the conventional multifractal-based methods and traditional CFAR methods, and the detection probability of detecting low-observable targets within sea clutters is close to 100%.

RUMOR SITUATION RECOGNITION BASED ON MULTIFRACTALS

In order to effectively identify rumors and further block their propagation, this present study established a rumor situation identification model based on multifractals and support vector machine (SVM), which considered the fractal theory and the situation of rumor propagation. First, the representative rumors and nonrumors about food safety were selected. The multifractal analysis was used to calculate the generalized fractal dimension spectrum of the two target states. After this, the generalized fractal dimension values were used as the input target eigenvector for the SVM, which was subsequently trained to obtain the best classification results. The experimental results show that the model can quickly and effectively identify rumors from the communication situation, thus providing further help for governance.

Facile synthesis of bismuth oxyhalogen-based Z-scheme photocatalyst for visible-light-driven pollutant removal: Kinetics, degradation pathways and mechanism

Water pollution caused by heavy metal and organic pollutant becomes a rigorous problem, thereby a clean and sustainable technology should be developed to resolve this situation. In this work, a novel AgI/Bi24O31Cl10 Z-scheme photocatalysis system was designed to overcome this problem. The prepared AgI/Bi24O31Cl10 composite was characterized by many means such as X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET). The designed Z-scheme photocatalysis system conquers difficulties of traditional photocatalysts of the fast photogenerated charge carrier recombination and weak redox ability, thereby held remarkable catalytic activity for Cr (VI) reduction and tetracycline (TC) oxidation, approximately 85.36% and 78.26% of tetracycline and Cr (VI) can be removed under visible light illumination for 1 h. Some factors like contaminant concentrations, inorganic cation, inorganic anion, and water resources on catalytic activity were explored and the influence mechanism was discoursed. Importantly, the cyclic experiment suggested that the removal efficiency did not have obvious loss after five consecutive experiments, confirming its stability and reusability. The photodegradation pathway of TC was also proposed according to liquid chromatography-mass/mass spectrometry (LC-MS) and three dimensional excitation-emission matrix fluorescence spectra (3D EEMs). Furthermore, this Z-scheme photocatalysis mechanism for Cr (VI) reduction and TC oxidation was proposed based on trapping experiment and electron spin resonance (ESR) measurement. This study sheds lights on the design of Z-scheme photocatalysis system with sunlight as driving force for refractory organic pollutants removal.

On correlation functions in -deformed CFTs

The deformation, built from the components of the stress tensor and of a current, is a universal irrelevant deformation of two-dimensional CFTs that preserves the left-moving conformal symmetry, while breaking locality on the right-moving side. Operators in the -deformed CFT are naturally labeled by the left-moving position and right-moving momentum and transform in representations of the one-dimensional extended conformal group. We derive an all-orders formula for the spectrum of conformal dimensions and charges of the deformed CFT, which we cross-check at leading order using conformal perturbation theory. We also compute the linear corrections to the one-dimensional OPE coefficients and comment on the extent to which the correlation functions in -deformed CFTs can be obtained from field-dependent coordinate transformations.

Emotionality of Turkish language and primary adaptation of affective English norms for Turkish

Emotional load assessment of the written words has gained considerable interest in psycholinguistics, semantics, and analysis of psychophysiological and electrophysiological correlates of emotional processing. Considering the lack of a publicly available database with affective ratings of contemporary verbal stimuli obtained from native Turkish speakers, we present the affective norms for two datasets of Turkish words carefully adapted from the Affective Norms for English Words (ANEW) database. The valence and arousal ratings are obtained from 61 college-aged participants for 127 highly arousing, emotionally-loaded words in the Adapted Turkish Affective List (ATAL). The ATAL ratings show a tendency of classifying fewer words as positive compared to the original list of stimuli, significantly higher arousal levels for positively rated Turkish stimuli compared to the negative and neutral words, and more congruence in arousal levels of positively exciting words. For the medium to high arousing 508 words in the Expanded Turkish Affective List (ETAL) that cover the whole 9-point spectrum of the valence dimension, 136 Turkish respondents from a wider age, education, and occupation background show higher excitability towards highly unpleasant words. Strong cross-linguistic correlations of + 0.968 between the valence ratings of ANEW and ATAL and + 0.878 for ANEW and ETAL demonstrate the ease of transferring and perceiving the valence levels across English and Turkish. The medium correlation of roughly + 0.450 between the English and Turkish arousal ratings account for lower excitation levels perceived by the native Turkish speakers and indicate the arousal dimension is similar to familiarity and originality in exhibiting more variations between different cultures. These findings demonstrate that this expanded database of partial affective normative ratings can be used as the ground truth for emotional and neurocognitive assessments, and that the presented methodology can be utilized for developing a comprehensive Turkish affective lexicon. The utilized word selection criteria also enable a cross-cultural analysis of adapted words in Turkish and other languages. Detailed normative ratings of this Turkish adaptation are included in the supplementary materials.

Spectrum and combinatorics of two-dimensional Ramanujan complexes

Ramanujan graphs have extremal spectral properties, which imply a remarkable combinatorial behavior. In this paper we compute the high dimensional Hodge-Laplace spectrum of Ramanujan triangle complexes, and show that it implies a combinatorial expansion property, and a pseudo-randomness result. For this purpose we prove a Cheeger-type inequality and a mixing lemma of independent interest.