Side effects of rodent control on non-target species: Rodenticides increase parasite and pathogen burden in great bustards

For many years anticoagulant rodenticides have been used in vole control campaigns, in spite of the proven risk of secondary poisoning of non-target predators and scavengers. In this paper we analyse for the first time great bustard exposure and intoxication by anticoagulant rodenticides in Spain, based on residues found in the livers of 71 bustard carcasses collected during 1991-2010. Ten individuals contained chlorophacinone and one flocoumafen. Chlorophacinone level was significantly correlated with the pathogen and parasite burden of intoxicated birds. Moreover, through the last 12 years the annual number of great bustards that present chlorophacinone in liver collected in our study areas was correlated with vole peaks at a nearby area, suggesting that the ingestion of rodenticide was proportional to the amounts spread in the fields. We conclude that rodenticide consumption is a regular event among great bustards when baited cereal is spread on fields, and that this may cause chronic weakening of intoxicated individuals, possibly affecting their survival. Future rodent control actions should consider these negative side effects on non target granivorous steppe and farmland species, particularly when they are globally threatened.     

Estimation of global solar radiation over the city of La Serena (Chile) using a neural network

An artificial neural network for the estimation of hourly global solar radiation in La Serena (Chile), was developed using data measured from a meteorological station. La Serena city (29°54′ S, 71°15′ W) is located in the bay area at south of the hyper-arid Atacama Desert. In this study, 25123 data points of global solar radiation of 5 years (2001–2005) were used to train the network and then 7618 data points of global solar radiation not used in the training process were predicted (years 2006 and 2007). The meteorological data used in the model were: wind speed, relative humidity, air temperature, and soil temperature. The results were compared with the real data and other models available in the literature, and shows that the neural network obtained can be properly trained and can estimate the hourly global radiation with acceptable accuracy.     

Proton conductive membranes based on doped sulfonated polytriazole

This work reports the preparation and characterization of proton conducting sulfonated polytriazole membranes doped with three different agents: 1H-benzimidazole-2-sulfonic acid, benzimidazole and phosphoric acid. The modified membranes were characterized by scanning electron microscopy (SEM), infrared spectra, thermogravimetric analysis (TGA), dynamical mechanical thermal analysis (DMTA) and electrochemical impedance spectroscopy (EIS). The addition of doping agents resulted in a decrease of the glass transition temperature. For membranes doped with 85 wt.% phosphoric acid solution proton conductivity increased up to 2·10⁻³ S cm⁻¹ at 120 °C and at 5% relative humidity. The performance of the phosphoric acid doped membranes was evaluated in a fuel cell set-up at 120 °C and 2.5% relative humidity.     

Chitosan-gelatin composites and bi-layer films with potential antimicrobial activity

The aims of this work were to develop composite (Chi-Ge) and bi-layer (Chi/Ge) edible and biodegradable films based on gelatin and chitosan. physico-chemical properties such as water resistance, transparency and color were analyzed. Composite and bi-layer systems were uniform, homogeneous and thin; they showed a compact structure indicating a good compatibility between components, which could interact by strong hydrogen bonding, as was confirmed by FTIR. Water vapor permeability (WVP) was determined. Both, bi-layer and laminated systems resulted effective alternatives to reduce WVP of chitosan control film. The tensile strength of composite and bi-layer system did not differ significantly (P > 0.05), but elongation at break of composite films was 40% higher (P < 0.05) than that of bi-layer film. Antimicrobial activity of the films was analyzed. The results indicated that both E. coli and L. monocytogenes showed sensitivity to all the films forming solutions. The inhibition halos of both pathogens to the solutions of Chi and Chi-Ge showed to be extremely sensitive. Results obtained with edible films indicated that only E. coli was sensitive to the combination Chi-Ge and Chi/Ge. Neat Chi film did not induce significant inhibition halos for none of the pathogens, which was quite surprising and still under study.     

Encapsulation of cinnamon and thyme essential oils components (cinnamaldehyde and thymol) in β-cyclodextrin: Effect of interactions with water on complex stability

Thymol and cinnamaldehyde formed inclusion complexes with β-cyclodextrin (β-CD) upon mixing the components in aqueous media and subsequent freeze–drying, as confirmed by differential scanning calorimetry. The samples were stored at constant relative humidities (RH) from 22% to 97%, at 25 °C. The release of encapsulated compounds was determined following the melting enthalpy of each guest. Water sorption isotherms for β-CD and the complexes showed constant and low water sorption at RH < 80%, then the uptake of water increased abruptly. The amount of sorbed water at each RH was smaller for the complexes than for β-CD. The guest molecules displaced water molecules from inside the cavity of β-CD. No thymol or cinnamaldehyde release was detected at RH < 84%, and it increased abruptly from 84% RH, coincidentally with the abrupt increase of sorbed water. Water sorption significantly affects β-CD complexes stability, which is thus governed by the shape of the water sorption isotherm.     

Ascorbic Acid Retention, Microbial Growth, and Sensory Acceptability of Lettuce Leaves Subjected to Mild Heat Shocks

Heat shocks not only produced a reduction in the initial content of ascorbic acid but also affected the rate of degradation of ascorbic acid during refrigerated storage. Samples treated at higher temperatures presented faster rates of degradation. The heat shocks produced an initial reduction in the counts of mesophilic aerobic microorganisms, with greater reductions associated with the higher shock temperatures. However, high shock temperatures promoted faster microbial growths during storage, probably due to the liberation of nutrients by the disruption of membrane barriers. The sensory attributes of lettuce leaves subjected to heat shocks presented mixed results. Thermal treatments affected the enzymatic activity, reducing browning phenomena, but also caused deleterious effects on surface color and texture of lettuce leaves. Heat shocks of 50°C could be useful for short‐term preservation of minimally processed lettuce, where the high rate of metabolic processes cause great deterioration of fresh products.     

Water Variability and the Economic Impacts on Small-Scale Farmers. A Farm Risk-Based Integrated Modelling Approach

Strengthening the planning of hydrological resources to optimize the use of water in agriculture is a key adaptation measure of the Chilean agricultural sector to cope with future climate change. To address this challenge, decision-makers call for tools capable of representing farmers’ behaviours under the likely stresses generated by future climate conditions. In this context, of special concern are the effects of water variability on small-scale farmers, who commonly operate with narrow profit margins and who lack access to financial resources and technological knowledge. This paper sheds light on the economic impacts of changes in water availability on small-scale agriculture. We provide a hydro-economic modelling framework that captures the socio-economic effects of water shocks on smallholders in the Vergara River Basin, Chile. This approach links a farm risk-based economic optimization model to a hydrologic simulation model adjusted for the basin. Our results indicate that at the aggregated level, there will be minor economic impacts of climate change on the basin’s small-scale agriculture, with small decreases in both expected utility and wealth. However, large differences in the economic impacts of wealthy and poor small-scale farmers are found. Changes in water availability, reduce the options of land reallocation to increase farmer’s expected utility, being the poor small-scale farmers the most negatively affected.     

Water Use and Climate Stressors in a Multiuser River Basin Setting: Who Benefits from Adaptation?

Adapting to new climate conditions will require an intricate mix of knowledge, planning, coordination, and foresight. There is increasing sectoral evidence on the implementation of successful adaptation actions. However, the success of these actions when we consider the interdependencies among sectors remains debatable. This paper aims to assess who benefits from implementing adaptation options in a multiuser river basin to both climate-induced and demographic stress on water use. Our analysis relies on a hydro-economic model that considers two sets of water users: agriculture and urban households. We innovate in our modelling approach by analyzing and explicitly integrating the household-level economic behavior through its water demand. We assess the cross-user consequences of autonomous and planned adaptation actions. We provide insights into the different trade-offs at the basin level, demonstrating the compatibilities and divergences between agriculture and household-level water demand. We found different consequences of implementing either autonomous or planned adaptation measures. For instance, a decentralized scheme would drive negative implications for the entire basin, although the less water-intensive sector will be better off. On the other hand, different policy interventions would drive positive consequences for the entire basin, with the most water-intensive sector benefiting the most. These results highlight the distributional consequences across users of different adaptation measures.

     

Single-step synthesis of sulfonated polyoxadiazoles and their use as proton conducting membranes

A single-step approach for the synthesis of sulfonated polyoxadiazoles from hydrazine sulfate was developed using non-sulfonated diacids in polyphosphoric acid. The post-sulfonation conditions were optimized by varying reaction time, medium and reagent concentrations in sulfuric acid, oleum and/or their mixtures. For the first time, a series of sulfonated polyoxadiazoles with ion exchange capacity (IEC) ranging from 1.26 to 2.7 meqiv. g⁻¹ and high molecular weight (about 40,0000 g mol⁻¹) were synthesized. The structures of the polymers were characterized by elemental analysis, ¹H NMR, and FTIR. Sulfonated polyoxadiazole membranes with high thermal stability indicated by observed glass-transition temperatures (T_g) ranging from 364 to 442 °C in sodium salt form and from 304 to 333 °C in acid form and with high mechanical properties (storage modulus about 3 GPa at 300 °C) have been prepared. The membrane stability to oxidation was investigated by soaking the film in Fenton's reagent at 80 °C for 1 h. The sulfonated polyoxadiazole membranes exhibited high oxidative stability, retaining 98–100% of their weight after the test. Proton conductivity values with the order of magnitude of 10⁻¹ to 10⁻² S cm⁻¹ at 80 °C and with relative humidity ranging from 100% to 20% were obtained.