Dissipative vortex solitons in 2D-lattices

We report the existence of stable symmetric vortex-type solutions for two-dimensional nonlinear discrete dissipative systems governed by a cubic-quintic complex Ginzburg-Landau equation. We construct a whole family of vortex solitons with a topological charge S = 1. Surprisingly, the dynamical evolution of unstable solutions of this family does not alter significantly their profile, instead their phase distribution completely changes. They transform into two-charges swirl-vortex solitons. We dynamically excite this novel structure showing its experimental feasibility.Comment: 4 pages, 20 figure

Spatial rogue waves in photorefractive SBN crystals

We report on the excitation of large-amplitude waves, with a probability of around 1% of total peaks, on a photorefractive SBN crystal by using a simple experimental setup at room temperature. We excite the system using a narrow Gaussian beam and observe different dynamical regimes tailored by the value and time rate of an applied voltage. We identify two main dynamical regimes: a caustic one for energy spreading and a speckling one for peak emergence. Our observations are well described by a two-dimensional Schr\"odinger model with saturable local nonlinearity.Comment: 4 pages, 4 figure

Nonlinear optical lattices with a void impurity

We examine a one-dimensional nonlinear (Kerr) waveguide array which contains a single "void" waveguide where the nonlinearity is identically zero. We uncover a new family of nonlinear localized modes centered at or near the void, and their stability properties. Unlike a usual impurity problem, here the void acts like a repulsive impurity causing the center of the simplest mode to lie to the side of the void's position. We also compute the stability of extended nonlinear modes showing significant differences from the usual homogeneous nonlinear array. The transmission of a nonlinear pulse across the void shows three main regimes, transmission, reflection and trapping at the void's position, and we identify a critical momentum for the pulse below (above) where the pulse gets reflected (transmitted), or trapped indefinitely at the void's position. For relatively wide pulses, we observe a steep increase from a regime of no transmission to a regime of high transmission, as the amplitude of the soliton increases beyond a critical wavevector value. Finally, we consider the transmission of an extended nonlinear wave across the void impurity numerically, finding a rather complex structure of the transmission as a function of wavevector, with the creation of more and more transmission gaps as nonlinearity increases. The overall transmittance decreases and disappears eventually, where the boundaries separating passing from non-passing regions are complex and fractal-like.Comment: 9 pages, 10 figure

A stochastic model of anomalous heat transport: analytical solution of the steady state

We consider a one-dimensional harmonic crystal with conservative noise, in contact with two stochastic Langevin heat baths at different temperatures. The noise term consists of collisions between neighbouring oscillators that exchange their momenta, with a rate $\gamma$. The stationary equations for the covariance matrix are exactly solved in the thermodynamic limit ($N\to\infty$). In particular, we derive an analytical expression for the temperature profile, which turns out to be independent of $\gamma$. Moreover, we obtain an exact expression for the leading term of the energy current, which scales as $1/\sqrt{\gamma N}$. Our theoretical results are finally found to be consistent with the numerical solutions of the covariance matrix for finite $N$.Comment: Minor changes in the text. To appear in Journal of Physics

Fatty acid profile and in vitro rumen fermentation characteristics of maize silage augmented with canola silage

The objective was to investigate the effect of replacing maize silage (MS) with canola silage (CS) on the chemical composition and fatty acid (FA) profile of total mixed rations (TMR) containing these silages, and on in vitro rumen fermentation and methane production from them. The canola (Brassica napus var. Monty) was cultivated on a small-scale agricultural farm and harvested at 148 days after sowing. Maize silage in a TMR was replaced with 0%, 15%, 25%, and 35% CS to make the rations CS0, CS15, CS25, and CS35, respectively. Proximate analyses of the rations were evaluated in a completely randomized design. The results showed that linolenic acid increased linearly with the level of CS, primarily at the expense of linoleic acid. In vitro dry matter digestibility (IVDMD) was similar among treatments. However, in vitro neutral detergent fibre digestibility (IVNDF) decreased linearly (P <0.05) when the CS proportion increased in the TMR. The lowest ammonia nitrogen content (P <0.05) was observed in CS35. The soluble fraction (A) increased (P <0.05) when the CS increased in the TMR from 0% to 35%. In vitro methane (CH4) production was lowest with CS25 and CS35, decreasing 34% and 23.9%, respectively, compared with CS0. Linolenic acid had a negative correlation with IVNDF (r = -0.94; P <0.05). The IVDMD and methane production were positively correlated (r = 0.60) (P <0.05). In conclusion, 25% and 35% augmentation of MS with CS in a TMR was an important source of linolenic acid (C18:3) and decreased in vitro methane production

An assessment of emerging networks in the fruit sector: The case of Inca berry in Ecuador

The diversification of agri-food products through emerging chains has a fundamental social and economic role in Ecuador. A substantial amount of research focused only on examining critical factors in terms of agronomic and environmental performance. However, there is a shift in the agri-food chain perspective and study towards more sustainable models of production, logistics trade, and consumption. Aspects such as the socio-economic sustainability, level of collaboration between actors, an adequate chain configuration, and the employment of smart governance mechanisms show the weaknesses where stakeholders can propose enhancements. In this respect, socio-economic and productive factors are consequential and still affecting the progress of these chains. Also, the current growth of market opportunities at the local and international level is a driver to support them by setting sustainable strategies. This study aimed to analyze socio-economic and production aspects to understand the dynamic across the emerging Inca berry (Physalis peruviana) chain located in Ecuador and bring forward potential strategies. Thus, chain vertical and horizontal imensioning was introduced to contribute with relevant insights. The framework applied accounts with a revision of primary and support activities, and flows of high and low relevance. The investigation clustered pre-production, production, and post-production tiers. Also, it executed the food chain mapping, the identification of chain actors, and application of surveys at the supply chain levels to identify strengths and weaknesses based on specific socio-economic and productive variables. Results stated several viable long-term strategies. Examples of those strategies are the diversification of marketing channels, the intervention of academic institutions to improve efficiency, productivity, and the associations' empowerment. All of them aimed at circular economic models. The main research contribution is the application of the chain configuration to assess the chain performance comprehensively. Based on the results, our recommendation is incorporating new indicators to analyze the environmental and institutional components profoundly

Vortex solitons of the discrete Ginzburg-Landau Equation

We have found several families of vortex soliton solutions in two-dimensional discrete dissipative systems governed by the cubic-quintic complex Ginzburg-Landau equation. There are symmetric and asymmetric solutions, and some of them have simultaneously two different topological charges. Their regions of existence and stability are determined. Additionally, we have analyzed the relation- ship between dissipation and stability for a number of solutions. We have obtained that dissipation favours the stability of the solutions.Comment: 7 pages, 11 figure

Population pharmacokinetics of benznidazole in adult patients with Chagas disease

AIM: To build a population pharmacokinetic (PopPK) model to characterize benznidazole (BNZ) pharmacokinetics in adults with chronic Chagas disease. METHODS: Prospective, open-label, single-center clinical trial(EudraCT:2011-002900-34;CINEBENZclinicaltrials.govnumber:NCT01755403), approved by the local ethics committee. Patients received 2.5mg/kg/12h (Abarax(R), Elea Laboratory, Argentina) for 60 days. Plasma BZN samples were taken at several times along the study and analyzed by HPLC-UV. The PopPK analysis was done with NONMEMv.7.3. Demographic and biological data were tested as covariates. Intraindividual, interoccasion and residual variability were modeled. Internal and external validations were completed to assess the robustness of the model. Later on, simulations were performed to generate the BNZ concentration-time course profile for different dosage regimens. RESULTS: A total of 358 plasma BZN concentrations from 39 patients were included in the analysis. A one-compartment-PK-model characterized by clearance(CL/F) and apparent volume of distribution(V/F) with first order absorption(Ka) and elimination, adequately described the data (CL/F:1.73 L/h; V/F:89.6 L; Ka:1.15 h-1). No covariates were found to be significant for CL/F and V/F. Internal and external validation of the final model showed adequate results. Data from simulations revealed that a dose of 2.5mg/kg/12h might lead to overexposure in the most of the patients. A lower dose (2.5mg/kg/24h) was able to achieve trough BNZ plasma concentrations within the accepted therapeutic range of 3-6 mg/L. CONCLUSION: A population PK model for BNZ in adults with chronic Chagas disease has been developed. Dosing simulations showed that a BNZ dose of 2.5 mg/kg/24h would adequately keep BNZ trough plasma concentrations within the recommended target range concentrations for the majority of patients