We address the problem of existence and stability of vector spatial solitons formed by two incoherently interacting optical beams in bulk Kerr and saturable media. We identify families of (2+1)-dimensional two-mode self-trapped beams, with and without a topological charge, and describe their properties analytically and numerically.Recent experimental observations of multidimensional spatial optical solitons in different types of nonlinear materials [1] call for a systematic analysis of the selftrapping of light in higher dimensions. When two (or more) fields interact nonlinearly, they can form multicomponent trapped states, known as vector solitons. Vector solitons, first theoretically studied in a (1+1)-D models [2], were observed in birefringent fibers and planar waveguides [3]. Fabricated waveguiding structure localizes such solitons in one of the two directions transverse to the direction of propagation, hence these solitons are effectively one-dimensional. It is only recently, that the theory and experiments on incoherent interaction and truly two-dimensional self-trapping of beams in a bulk (saturable) medium merged [4], indicating progress towards the observation and study of different types of (2+1)-D vector solitons and their interactions.The practical possibility of such an observation greatly depends upon the soliton stability in the media with realistic, Kerr or saturable nonlinearity. It is known that scalar (one-component), fundamental (2+1)-D solitons are stable in saturable media [1], but they exhibit critical collapse in Kerr-type media [5]. However, as in the case of (1+1)-D vector solitons [6], both existence and stability of multi-dimensional vector solitons are nontrivial issues, which have not been systematically adressed so far.In this Letter, we study (2+1)-D vector solitons in Kerr and saturable media. We analyze two classes of such solitons. First, we consider solitons formed by the coupling of two fundamental modes; such solitons are always bellshaped. Secondly, we analyze the coupling between the fundamental mode of one field and the first-order mode (i.e. that carrying a topological charge) of the other field. In the latter case the vector solitons may possess a ring structure and are expected to be analogous to the twohump (1+1)-D vector solitons recently proved to be stable in a saturable medium [6].We consider two incoherently interacting beams propagating along the direction z in a bulk, weakly nonlinear optical medium. For a Kerr medium, the problem is described by the normalized, coupled equations for the slowly varying beam envelopes, E 1 and E 2 , (1) where ∆ ⊥ is the transverse Laplacian, and σ measures the relative strength of cross-and self-phase modulation effects. Depending on the polarization of the beams, the nature of nonlinearity, and anisotropy of the material, σ varies over a wide range. For a Kerr-type material with nonresonant electronic nonlinearity σ ≥ 2/3, whereas for a nonlinearity due to molecular orientation σ ≤ 7 [7]. We look for solutions of Eqs.(1) in th...

We study, numerically and analytically, linear and nonlinear waveguides induced by optical vortex solitons in a Kerr medium. Both fundamental and first-order guided modes are analyzed, as well as cases of effective defocusing and focusing nonlinearity.

The use of hyphenated analytical techniques in forensic drug screening enables simultaneous identification of a wide range of different compounds. However, the appearance of drug seizures containing new substances, mainly new psychoactive substances (NPS), is steadily increasing. These new and other already known substances often possess structural similarities and consequently they exhibit spectral data with slight differences. This situation has made the criteria that ensure indubitable identification of compounds increasingly important. In this work, 6 new synthetic cathinones that have not yet appeared in any Swedish drug seizures were synthesized. Their chemical structures were similar to those of already known cathinone analogs of which 42 were also included in the study. Hence, a total of 48 synthetic cathinones making up sets of homologous and regioisomeric compounds were used to challenge the capabilities of various analytical techniques commonly applied in forensic drug screening, ie, gas chromatography-mass spectrometry (GC-MS), gas chromatography-Fourier transform infrared spectroscopy (GC-FTIR), nuclear magnetic resonance (NMR), and liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Special attention was paid to the capabilities of GC-MS and GC-FTIR to distinguish between the synthetic cathinones and the results showed that neither GC-MS nor GC-FTIR alone can successfully differentiate between all synthetic cathinones. However, the 2 techniques proved to be complementary and their combined use is therefore beneficial. For example, the structural homologs were better differentiated by GC-MS, while GC-FTIR performed better for the regioisomers. Further, new spectroscopic data of the synthesized cathinone analogs is hereby presented for the forensic community. The synthetic work also showed that cathinone reference compounds can be produced in few reaction steps.

The present study validated a Swedish version of the 47-item Coaching Behavior Scale for Sport (CBS-S). Sample 1 consisted of 506 team sport athletes [262 men and 244 women; mean age: 22.20, standard deviation (SD) = 3.90] distributed across 41 coaches at the two highest national levels of various sports. Athletes completed the CBS-S and established questionnaires of coaching behaviors (LSS), self-confidence (CSAI-2R), and coach-athlete relationship (CART-Q). An additional sample of 39 basketball players (21 men and 18 women; mean age = 17.40, SD = 2.39) completed the CBS-S twice, approximately 4 weeks apart. Confirmatory factor analysis showed an acceptable model fit for the seven-factor version of the CBS-S, although two items of the negative personal rapport subscale displayed insufficient factor loadings. Correlations between the subscales of the CBS-S and established instruments were in accordance with theoretical expectations, supporting the concurrent validity. Cronbach's alpha (> 0.82) for all dimensions provided support for the reliability of the CBS-S, and test-retest correlations indicated moderate stability over time. Cultural differences in the assessment of coaching behaviors and the usability of the CBS-S by coaches for self-reflection and development are discussed.