Dynamical generation of interwoven soliton trains by nonlinear emission in binary Bose-Einstein condensates

We propose a method for the generation of trains of alternating bright solitons in two-component Bose-Einstein condensates, using controlled emission of nonlinear matter-waves in the uncoupled regime with spatially-varying intra-species interaction and out-of-phase oscillations of the ground states in the trap. Under this scheme, solitons are sequentially launched from the different components, and interact with each other through phase-independent cross-coupling. We obtain an analytical estimation of the critical condition for soliton emission using a geometric guiding model, in analogy with integrated optical systems. In addition, we show how strong initial perturbations in the system can trigger the spontaneous generation of supersolitons, i.e. localized phonon-like excitations of the soliton trains. Finally, we demonstrate the controllable generation of slow and fast supersolitons by adding external localized potentials in the nonlinear region

The effects of Reiki treatment on mental health professionals who are at risk for secondary traumatic stress

The purpose of this cross-sectional experimental study was to examine the effects of Reiki on risk level for secondary traumatic stress (STS) among mental health professionals, such as, social workers and licensed professional counselor (LPCs). The sample (N=67) was mostly composed of master social work students (MSW) (61%) from the School of Social Work at Louisiana State University (LSU), professionals social workers (34%), and LPCs (5%). Study participants were randomly assigned to one of three treatment groups: Reiki, placebo or control group. Dependent variables measured at pretest and posttest were: risk level for STS, anxiety, depression, somatic symptoms, anger and hopelessness. Multivariate analysis of variance was conducted to determine if there was a difference between treatment groups. No significant difference was found between the Reiki, placebo or control groups on any of the variables measured. Implications for the social work profession are discussed

Implementation of liquid culture for tuberculosis diagnosis in a remote setting: lessons learned.

Although sputum smear microscopy is the primary method for tuberculosis (TB) diagnosis in low-resource settings, it has low sensitivity. The World Health Organization recommends the use of liquid culture techniques for TB diagnosis and drug susceptibility testing in low- and middle-income countries. An evaluation of samples from southern Sudan found that culture was able to detect cases of active pulmonary TB and extra-pulmonary TB missed by conventional smear microscopy. However, the long delays involved in obtaining culture results meant that they were usually not clinically useful, and high rates of non-tuberculous mycobacteria isolation made interpretation of results difficult. Improvements in diagnostic capacity and rapid speciation facilities, either on-site or through a local reference laboratory, are crucial

Polarization-Tailored Raman Frequency Conversion in Chiral Gas-Filled Hollow Core Photonic Crystal Fibers

Broadband-tunable sources of circularly-polarized light are crucial in fields such as laser science, biomedicine and spectroscopy. Conventional sources rely on nonlinear wavelength conversion and polarization control using standard optical components, and are limited by the availability of suitably transparent crystals and glasses. Although gas-filled hollow-core photonic crystal fiber provides pressure-tunable dispersion, long well-controlled optical path-lengths, and high Raman conversion efficiency, it is unable to preserve circular polarization state, typically exhibiting weak linear birefringence. Here we report a revolutionary approach based on helically-twisted hollow-core photonic crystal fiber, which displays circular birefringence, thus robustly maintaining circular polarization state against external perturbations. This makes it possible to generate pure circularly-polarized Stokes and anti-Stokes signals by rotational Raman scattering in hydrogen. The polarization state of the frequency-shifted Raman bands can be continuously varied by tuning the gas pressure in the vicinity of the gain suppression point. The results pave the way to a new generation of compact and efficient fiber-based sources of broadband light with fully-controllable polarization state.Comment: 5 pages, 4 figure

Novel mid-infrared dispersive wave generation in gas-filled PCF by transient ionization-driven changes in dispersion

Gas-filled hollow-core photonic crystal fibre (PCF) is being used to generate ever wider supercontinuum spectra, in particular via dispersive wave (DW) emission in the deep and vacuum ultraviolet, with a multitude of applications. DWs are the result of the resonant transfer of energy from a self-compressed soliton, a process which relies crucially on phase matching. It was recently predicted that, in the strong-field regime, the additional transient anomalous dispersion introduced by gas ionization would allow phase-matched DW generation in the mid-infrared (MIR)-something that is forbidden in the absence of free electrons. Here we report for the first time the experimental observation of such MIR DWs, embedded in a 4.7-octave-wide supercontinuum that uniquely reaches simultaneously to the vacuum ultraviolet, with up to 1.7 W of total average power

Conversion of HVAC Lines into HVDC in Transmission Expansion Planning

This paper presents a transmission planning methodology that considers the conversion of HVAC transmission lines to HVDC as an alternative of expansion of power systems, as a consequence of restrictions for the construction of new lines. The transmission expansion planning problem formulates an optimization problem that minimizes the total cost that includes the investment cost to convert lines from HVAC to HVDC and possible required reinforcements of the power system prior to the conversion. The costs analysis assesses the impact of the conversion on the reliability because transmission lines are out of service during the conversion work. The presented methodology is applied to a test system considering a planning a horizon of 10 years

Synthesis, molecular modelling and NLO properties of new ytterbium(iii) complexes with vildagliptin

Two nonlinear optical ytterbium(III) complexes with vildagliptin have been synthesized and their ground state geometries have been predicted by semi-empirical quantum chemistry methods: [Yb(vilda)3(acac)] and [Yb(vilda)2(acac)(bipy)], where vilda = vildagliptin, acac = acetylacetonate and bipy = 2,2'-bipyridine. ATR-Fourier transform infrared (ATR-FTIR) spectral studies have been carried out to identify the functional groups of the novel complexes. The third order nonlinear optical response has been experimentally studied using Z-scan and P-scan methods, and static and frequency dependent second hyperpolarizabilities have been theoretically investigated using the Sparkle/PM6 model. The novel materials in diluted solutions have nonlinear refractive indices comparable to that of carbon disulphide.J.A. Novoa-López would like to thank University of Vigo for its financial support under “Axudas predoutorais: Áreas de especial dificultade” PhD scholarship program. Support by Xunta de Galicia under projects K133131H64102 and K044131H64502 is gratefully acknowledged by P. Chamorro-Posada, H. Michinel and P. Martín-Ramos are grateful to Junta de Castilla y León for providing funds under project VA300A12-1

Rare failures of DNA bar codes to separate morphologically distinct species in a biodiversity survey of Iberian leaf beetles

During a survey of genetic and species diversity patterns of leaf beetle (Coleoptera: Chrysomelidae) assemblages across the Iberian Peninsula we found a broad congruence between morphologically delimited species and variation in the cytochrome oxidase (cox1) gene. However, one species pair each in the genera Longitarsus Berthold and Pachybrachis Chevrolat was inseparable using molecular methods, whereas diagnostic morphological characters (including male or female genitalia) unequivocally separated the named species. Parsimony haplotype networks and maximum likelihood trees built from cox1 showed high genetic structure within each species pair, but no correlation with the morphological types and neither with geographic distributions. This contrasted with all analysed congeneric species, which were recovered as monophyletic. A limited number of specimens were sequenced for the nuclear 18S rRNA gene, which showed no or very limited variation within the species pair and no separation of morphological types. These results suggest that processes of lineage sorting for either group are lagging behind the clear morphological and presumably reproductive separation. In the Iberian chrysomelids, incongruence between DNA-based and morphological delimitations is a rare exception, but the discovery of these species pairs may be useful as an evolutionary model for studying the process of speciation in this ecological and geographical setting. In addition, the study of biodiversity patterns based on DNA requires an evolutionary understanding of these incongruences and their potential causes.AB was funded by the Spanish Ministry of Science and Innovation (grant CGL2009-10111). CGR is funded by the Xunta de Galicia(postdoctoral fellowship POS-A/2012/052)S