Stable dark and bright soliton Kerr combs can coexist in normal dispersion resonators

Using the Lugiato-Lefever model, we analyze the effects of third order chromatic dispersion on the existence and stability of dark and bright soliton Kerr frequency combs in the normal dispersion regime. While in the absence of third order dispersion only dark solitons exist over an extended parameter range, we find that third order dispersion allows for stable dark and bright solitons to coexist. Reversibility is broken and the shape of the switching waves connecting the top and bottom homogeneous solutions is modified. Bright solitons come into existence thanks to the generation of oscillations in the switching wave profiles. Finally, oscillatory instabilities of dark solitons are also suppressed in the presence of sufficiently strong third order dispersion

Canonical circuit quantization with linear nonreciprocal devices

Nonreciprocal devices effectively mimic the breaking of time-reversal symmetry for the subspace of dynamical variables that they couple, and can be used to create chiral information processing networks. We study the systematic inclusion of ideal gyrators and circulators into Lagrangian and Hamiltonian descriptions of lumped-element electrical networks. The proposed theory is of wide applicability in general nonreciprocal networks on the quantum regime. We apply it to pedagogical and pathological examples of circuits containing Josephson junctions and ideal nonreciprocal elements described by admittance matrices, and compare it with the more involved treatment of circuits based on nonreciprocal devices characterized by impedance or scattering matrices. Finally, we discuss the dual quantization of circuits containing phase-slip junctions and nonreciprocal devices.Comment: 12 pages, 4 figures; changes made to match the accepted version in PR

Applicability of satellite remote sensing for detection and monitoring of coal strip mining activities

The author has identified the following significant results. Large areas covered by orbital photography allows the user to estimate the acreage of strip mining activity from a few frames. Infrared photography both in color and in black and white transparencies was found to be the best suited for this purpose

Multilevel correlates of household anthropometric typologies in Colombian mothers and their infants

Background. The aim of this study was to establish the association of maternal, family, and contextual correlates of anthropometric typologies at the household level in Colombia using 2005 Demographic Health Survey (DHS/ENDS) data.Methods. Household-level information from mothers 18-49 years old and their children less than 5 years old was included. Stunting and overweight were assessed for each child. Mothers were classified according to their body mass index. Four anthropometric typologies at the household level were constructed: normal, underweight, overweight, and dual burden. Four three-level [households (n = 8598) nested within municipalities (n = 226), nested within states (n = 32)] hierarchical polytomous logistic models were developed. Household log-odds of belonging to one of the four anthropometric categories, holding 'normal' as the reference group, were obtained.Results. This study found that anthropometric typologies were associated with maternal and family characteristics of maternal age, parity, maternal education, and wealth index. Higher municipal living conditions index was associated with a lower likelihood of underweight typology and a higher likelihood of overweight typology. Higher population density was associated with a lower likelihood of overweight typology.Conclusion. Distal and proximal determinants of the various anthropometric typologies at the household level should be taken into account when framing policies and designing interventions to reduce malnutrition in Colombia. Copyright © The Author(s) 2018

Interaction of solitons and the formation of bound states in the generalized Lugiato-Lefever equation

Bound states, also called soliton molecules, can form as a result of the interaction between individual solitons. This interaction is mediated through the tails of each soliton that overlap with one another. When such soliton tails have spatial oscillations, locking or pinning between two solitons can occur at fixed distances related with the wavelength of these oscillations, thus forming a bound state. In this work, we study the formation and stability of various types of bound states in the Lugiato-Lefever equation by computing their interaction potential and by analyzing the properties of the oscillatory tails. Moreover, we study the effect of higher order dispersion and noise in the pump intensity on the dynamics of bound states. In doing so, we reveal that perturbations to the Lugiato-Lefever equation that maintain reversibility, such as fourth order dispersion, lead to bound states that tend to separate from one another in time when noise is added. This separation force is determined by the shape of the envelope of the interaction potential, as well as an additional Brownian ratchet effect. In systems with broken reversibility, such as third order dispersion, this ratchet effect continues to push solitons within a bound state apart. However, the force generated by the envelope of the potential is now such that it pushes the solitons towards each other, leading to a null net drift of the solitons.Comment: 13 pages, 13 figure

Repeated batch for dye degradation in an airlift bioreactor by laccase entrapped in copper alginate

A repeated batch of synthetic dye decolorization was efficiently demonstrated in a 5 L airlift bioreactor. A laccase from Ganoderma sp. KU-Alk4, degrading commercial aromatic dyes was selected. The crude enzyme extract expressed laccase activity, and was immobilized under optimal conditions in copper-alginate beads, 3 IU/bead. The immobilized enzyme showed high efficiency in degrading various synthetic dyes under non-buffered conditions, in particular the indigoid dye Indigo Carmine. The immobilized laccase also showed marked increase in stability toward temperature and pH when compared with free enzyme preparation. Immobilization enhanced its temperature stability to maintain initial activity up to 55 °C, ten degrees higher than the free enzyme. The immobilized laccase was stable in the alkaline region up to pH 10.0. The dye decolorization system in 5 L airlift bioreactor was demonstrated with 25 mg/L Indigo Carmine dissolved in tap water and a total immobilized laccase activity of 6 × 104 IU. Airflow rate was the most important factor affecting the number of batch runs and the time for 100% dye degradation. An optimal airflow rate was of 4 L/min. Fourteen batch runs of complete dye degradation were successfully completed with only a single enzyme supplementation, and this could be a feasible system for operation in industry. Total dye degraded by this repeated process at 4 L/min airflow rate was 1.8 g. Isatin sulfonic acid was a metabolic product of Indigo Carmine degradation catalyzed by the immobilized laccase. This development of an effective repeatable bioprocess using enzymes for the treatment of dye-contaminated effluent has potential for implementation on an industrial scale