Relative contribution of dietary carotenoids and vitamin E to visual and chemical sexual signals of male Iberian green lizards: an experimental test

Carotenoid-based sexual ornaments are widespread, but the role of carotenoids as honest signalers in the trade-off between coloration and antioxidant protection remains controversial. It has been suggested that the function of carotenoids might not be an antioxidant per se, but that colorful carotenoids may indirectly reflect the levels of nonpigmentary antioxidants, such as melatonin or vitamin E. We experimentally fed male Iberian green lizards (Lacerta schreiberi) additional carotenoids or vitamin E alone, or a combination of carotenoids and vitamin E dissolved in soybean oil, whereas a control group only received soybean oil. We examined the effects of the dietary supplementations on characteristics of lizard sexual coloration and of the chemical profile of femoral gland secretions. Results indicated that both carotenoids and vitamin E in the diet increased the expression of some visual signals (head and chest, but not dorsum) in comparison to controls. However, different traits were differentially affected, and in many cases, the addition of vitamin E, alone or in combination with carotenoids, had a greater effect on the expression of coloration than the addition of carotenoids alone, even for carotenoid-dependent ornaments. Our results support the idea that other nonpigmentary antioxidants, such as vitamin E, are needed in addition to carotenoids to increase the expression of coloration of L. schreiberi lizards. Therefore, coloration may only indirectly reflect the levels of nonpigmentary antioxidants. In contrast, an increase in dietary nonpigmentary antioxidant vitamin E was directly reflected in the chemical signals. Because of an observed concordance between visual and chemical signals, we suggest that both may be used in different contexts albeit conveying similar messages in different sensory channels.     

Mechanical and Thermal Properties of Biocomposites Based on Polyethylene from Renewable Resources Modified with Ionic Liquids

Journal of Polymers and the Environment - Biocomposites based on polyethylene from renewable resources derived from sugar cane as raw material were modified with phosphonium ionic liquids....     

Global burned-land estimation in Latin America using MODIS composite data.

This paper presents results of the AQL2004 project, which has been develope within the GOFC-GOLD Latin American network of remote sensing and forest fires (RedLatif). The project intended to obtain monthly burned-land maps of the entire region, from Mexico to Patagonia, using MODIS (moderate-resolution imaging spectroradiometer) reflectance data. The project has been organized in three different phases: acquisition and preprocessing of satellite data; discrimination of burned pixels; and validation of results. In the first phase, input data consisting of 32-day composites of MODIS 500-m reflectance data generated by the Global Land Cover Facility (GLCF) of the University of Maryland (College Park, Maryland, U.S.A.) were collected and processed. The discrimination of burned areas was addressed in two steps: searching for "burned core" pixels using postfire spectral indices and multitemporal change detection and mapping of burned scars using contextual techniques. The validation phase was based on visual analysis of Landsat and CBERS (China-Brazil Earth Resources Satellite) images. Validation of the burned-land category showed an agreement ranging from 30% to 60%, depending on the ecosystem and vegetation species present. The total burned area for the entire year was estimated to be 153 215 km2. The most affected countries in relation to their territory were Cuba, Colombia, Bolivia, and Venezuela. Burned areas were found in most land covers; herbaceous vegetation (savannas and grasslands) presented the highest proportions of burned area, while perennial forest had the lowest proportions. The importance of croplands in the total burned area should be taken with reserve, since this cover presented the highest commission errors. The importance of generating systematic products of burned land areas for different ecological processes is emphasized.     

LC-MS/MS determination of pesticide residues in fruits and vegetables

The aim of the research is to evaluate pesticide residue contamination of fresh and frozen fruits and vegetables, agricultural raw material, purchased from Polish farmers for production of frozen fruits and vegetables, and the estimation of the multiresidue method effectiveness expressed as the proportion of pesticides detected in food samples to the total number of pesticides analyzed by multiresidue methods. A total of 144 samples (of black currants, red currants, raspberries, cherries, strawberries, blackberries, cauliflowers and broccoli) were analyzed using LC-MS/MS method for the determination of 60 pesticides. QuEChERS extraction, matrix-matched calibration and dynamic multiple reaction monitoring method were used. Residues of 15 compounds, mainly fungicides and insecticides, were detected in 46 samples. The percentage of samples with residues above the maximum residue levels (MRL) was 15%, whereas samples with residues below MRL were 17%. A total of 13 samples contained more than one pesticide residue. Pesticide residues were detected most often in samples of black currants (50%), broccoli (36.4%), raspberries (29%) and red currants (21.8%). The most frequently detected pesticides were carbendazim and acetamiprid. The proportion of pesticides detected during our study to the total number of analyzed pesticides amounted to 25%. It was compared to literature findings. For three fourth of multiresidue methods, the proportion was below 50% for methods developed for the analysis of less than 100 pesticides, and below 30% for methods developed for the analysis of more than 100 pesticides. It appears that a lot of efforts and means is lost on pesticides never or rarely detected in examined samples. The workload and cost effectiveness of the development and application of multiresidue methods along with the range of pesticides covered by the method should be carefully and thoroughly considered anytime when a new method or workflow is developed. Including non-targeted screenings in pesticide residue control seems to be an alternative worth considering.     

Dissipation of glyphosate and aminomethylphosphonic acid in water and sediment of two Canadian prairie wetlands

Glyphosate [N-(phosphonomethyl)glycine] is the active ingredient of several herbicide products first registered for use in 1974 under the tradename Roundup. The use of glyphosate-based herbicides has increased dramatically over the last two decades particularly in association with the adoption of glyphosate-tolerant crops. Glyphosate has been detected in a range of surface waters but this is the first study to monitor its fate in prairie wetlands situated in agricultural fields. An ephemeral wetland (E) and a semi-permanent wetland (SP) were each divided into halves using a polyvinyl curtain. One half of each wetland was fortified with glyphosate with the added mass simulating an accidental direct overspray. Glyphosate dissipated rapidly in the water column of the two prairie wetlands studied (DT₅₀ values of 1.3 and 4.8 d) which may effectively reduce the impact of exposure of aquatic biota to the herbicide. Degradation of glyphosate to its major metabolite aminomethylphosphonic acid (AMPA) and sorption of the herbicide to bottom sediment were more important pathways for the dissipation of glyphosate from the water column than movement of the herbicide with infiltrating water. Presently, we are not aware of any Canadian guidelines for glyphosate residues in sediment of aquatic ecosystems. Since a substantial portion of glyphosate entering prairie wetlands will become associated with bottom sediments, particularly in ephemeral wetlands, guidelines would need to be developed to assess the protection of organisms that spend all or part of their lifecycle in sediment.     

Wind-induced pressure loads on buildings in tandem arrangement in urban environment

Environmental Fluid Mechanics - The wind-induced pressure loads are affected by a broad spectrum of elements involving flow conditions, buildings geometry, or neighbourhoods. Computational fluid...     

The Langmuir two-surface equation as a model for cadmium adsorption on peat

The Langmuir isotherm equation is often used to describe the adsorption of cadmium on peat. If the total surface onsists of two or more populations of sites with different bonding energies, it is proposed that the Langmuir two-surface equation be used. The effects of the contact time and pH on adsorption were investigated in batch experiments. Adsorption batch isotherm studies were carried out by using 12 solutions with initial concentrations of 5–110 mg/l. The samples were analysed by using axial ICP-AES. Adsorption data were compared using four different linearizations (Lineweaver-Burk, Eadie-Hofstee, Scatchard and Langmuir linearizations). Better results among linearizations were found with the Langmuir linearization, but the results obtained by using the nonlinear regression were still the best. A new, nonlinear regression method for the calculation of the equation constants was created by using the system of equations and these findings were compared to the results found using earlier methods.     

Gastroenteric Viruses Detection in a Drinking Water Distribution-to-Consumption System in a Low-Income Community in Rio de Janeiro

Food and Environmental Virology - The availability of drinking water is one of the main determinants of quality of life, disease prevention and the promotion of health. Viruses are important agents...