Transport of radiocesium in mycelium and its translocation to fruitbodies of a saprophytic macromycete

We present a new protocol to study fluxes of radionuclides and other xenobiotics in saprophytic fungi. This simple method has successfully been used to evaluate transport of radiocesium in hyphae of Pleurotus eryngii and its translocation to fruitbodies.     

Measuring the Social Recreation Per-Day Net Benefit of the Wildlife Amenities of a National Park: A Count-Data Travel-Cost Approach

In this article, we apply count-data travel-cost methods to a truncated sample of visitors to estimate the Peneda-Gerês National Park (PGNP) average consumer surplus (CS) for each day of visit. The measurement of recreation demand is highly specific because it is calculated by number of days of stay per visit. We therefore propose the application of altered truncated count-data models or truncated count-data models on grouped data to estimate a single, on-site individual recreation demand function, with the price (cost) of each recreation day per trip equal to out-of-pocket and time travel plus out-of-pocket and on-site time costs. We further check the sensitivity of coefficient estimations to alternative models and analyse the welfare measure precision by using the delta and simulation methods by Creel and Loomis. With simulated limits, CS is estimated to be €194 (range €116 to €448). This information is of use in the quest to improve government policy and PNPG management and conservation as well as promote nature-based tourism. To our knowledge, this is the first attempt to measure the average recreation net benefits of each day of stay generated by a national park by using truncated altered and truncated grouped count-data travel-cost models based on observing the individual number of days of stay.     

Spatial factors affecting statistical power in testing marine fauna displacement

Impacts of offshore wind farms on marine fauna are largely unknown. Therefore, one commonly adheres to the precautionary principle, which states that one shall take action to avoid potentially damaging impacts on marine ecosystems, even when full scientific certainty is lacking. We implement this principle by means of a statistical power analysis including spatial factors. Implementation is based on geostatistical simulations, accommodating for zero-inflation in species data. We investigate scenarios in which an impact assessment still has to be carried out. Our results show that the environmental conditions at the time of the survey is the most influential factor on power. This is followed by survey effort and species abundance in the reference situation. Spatial dependence in species numbers at local scales affects power, but its effect is smaller for the scenarios investigated. Our findings can be used to improve effectiveness of the economical investment for monitoring surveys. In addition, unnecessary extra survey effort, and related costs, can be avoided when spatial dependence in species abundance is present and no improvement on power is achieved.     

Invisible floral larcenies: microbial communities degrade floral nectar of bumble bee-pollinated plants

The ecology of nectarivorous microbial communities remains virtually unknown, which precludes elucidating whether these organisms play some role in plant-pollinator mutualisms beyond minor commensalism. We simultaneously assessed microbial abundance and nectar composition at the individual nectary level in flowers of three southern Spanish bumble bee-pollinated plants (Helleborus foetidus, Aquilegia vulgaris, and Aquilegia pyrenaica cazorlensis). Yeasts were frequent and abundant in nectar of all species, and variation in yeast density was correlated with drastic changes in nectar sugar concentration and composition. Yeast communities built up in nectar from early to late floral stages, at which time all nectaries contained yeasts, often at densities between 10(4) and 10(5) cells/mm3. Total sugar concentration and percentage sucrose declined, and percentage fructose increased, with increasing density of yeast cells in nectar. Among-nectary variation in microbial density accounted for 65% (H. foetidus and A. vulgaris) and 35% (A. p. cazorlensis) of intraspecific variance in nectar sugar composition, and 60% (H. foetidus) and 38% (A. vulgaris) of variance in nectar concentration. Our results provide compelling evidence that nectar microbial communities can have detrimental effects on plants and/or pollinators via extensive nectar degradation and also call for a more careful interpretation of nectar traits in the future, if uncontrolled for yeasts.     

Methodology for quantification of waste generated in Spanish railway construction works

In the last years, the European Union (EU) has been focused on the reduction of construction and demolition (C&D) waste. Specifically, in 2006, Spain generated roughly 47million tons of C&D waste, of which only 13.6% was recycled. This situation has lead to the drawing up of many regulations on C&D waste during the past years forcing EU countries to include new measures for waste prevention and recycling. Among these measures, the mandatory obligation to quantify the C&D waste expected to be originated during a construction project is mandated. However, limited data is available on civil engineering projects. Therefore, the aim of this research study is to improve C&D waste management in railway projects, by developing a model for C&D waste quantification. For this purpose, we develop two equations which estimate in advance the amount, both in weight and volume, of the C&D waste likely to be generated in railway construction projects, including the category of C&D waste generated for the entire project.     

Extractable atrazine and its metabolites in agricultural soils from the temperate humid zone

Extractable atrazine and its metabolites (hydroxyatrazine, deethylatrazine and deisopropylatrazine) were evaluated in agricultural soils from the temperate humid zone (Galicia, NW Spain) under laboratory conditions. The experiment was performed with five soils with different properties (organic C, soil texture and atrazine application history), both unamended and treated with atrazine at field application rate. Measurements of the atrazine compounds were made at different time intervals (1, 3, 6, 9 and 12 weeks) during a 3-month incubation period. Results showed that only hydroxyatrazine was detected in the extractable fraction of the unamended soils, with values remaining relatively constant throughout the incubation period. Atrazine addition notably increased the concentration of the parent compound and its degradation products; deisopropylatrazine and hydroxyatrazine were the main metabolites detected in the extractable fraction of the treated soils, whereas deethylatrazine was not detected. After 7 days incubation, values of total extractable residues, expressed as percentage of initially added atrazine, ranged from 75 to 86% (25–68% of atrazine, 7–11% of hydroxyatrazine and 9–57% of deisopropylatrazine). The values decreased rapidly during the first 3 weeks of incubation, showing values of 2–8% in soils with higher atrazine application and from 28 to 30% in soils with lower application history. At the end of the incubation, 2–8% of total extractable residues were still detected (0–4% of atrazine, 2–3% of hydroxyatrazine and 0–2% of deisopropylatrazine), indicating a residual effect of atrazine addition. These variations in the extractable fraction indicated that most added atrazine was rapidly degraded, especially in soils with higher application history.     

Can stable isotope ratios provide for community-wide measures of trophic structure?

Stable isotope ratios (typically of carbon and nitrogen) provide one representation of an organism's trophic niche and are widely used to examine aspects of food web structure. Yet stable isotopes have not been applied to quantitatively characterize community-wide aspects of trophic structure (i.e., at the level of an entire food web). We propose quantitative metrics that can be used to this end, drawing on similar approaches from ecomorphology research. For example, the convex hull area occupied by species in delta13C-delta15N niche space is a representation of the total extent of trophic diversity within a food web, whereas mean nearest neighbor distance among all species pairs is a measure of species packing within trophic niche space. To facilitate discussion of opportunities and limitations of the metrics, we provide empirical and conceptual examples drawn from Bahamian tidal creek food webs. These examples illustrate how this methodology can be used to quantify trophic diversity and trophic redundancy in food webs, as well as to link individual species to characteristics of the food web in which they are embedded. Building from extensive applications of stable isotope ratios by ecologists, the community-wide metrics may provide a new perspective on food web structure, function, and dynamics.     

High CO2 permeation using a new Ce0.85Gd0.15O2-δ-LaNiO3 composite ceramic–carbonate dual-phase membrane

This work shows the synthesis,characterization and evaluation of dense-ceramic membranes made of Ce_0.85Gd_0.15O_2-δ-LaNiO₃(CG-LN) composites,where the fluorite-perovskite ratio (CG:LN) was varied as follows:75:25,80:20 and 85:15 wt.%.Supports were initially characterized by XRD,SEM and electrical conductivity (using vacuum and oxygen atmospheres),to determine the composition,microstructural and ionic-electronic conductivity properties.Later,supports were...     

Characterisation of sugar cane straw waste as pozzolanic material for construction: calcining temperature and kinetic parameters

This paper reports on the influence of calcining temperature (800 and 1000 degrees C) on the pozzolanic activation of sugar cane straw (SCS). The reaction kinetics of SCS ash-lime mixtures were inferred from physicochemical characteristics (X-ray diffraction patterns and thermogravimetry analysis. The fitting of a kinetic-diffusive model to the experimental data (fixed lime versus time) allowed the computing of the kinetic parameters (reaction rate constant) of the pozzolanic reaction. Results obtained confirm that the sugar cane straw ash (SCSA) calcined at 800 and 1000 degrees C have properties indicative of very high pozzolanic activity. No influence of calcining temperature on the pozzolanic activity was observed. Also, no crystalline compounds during the pozzolanic reaction were identified up to 90 days of reaction. Environmental durability and strength of the consequential mortars remain to be assessed.     

Modifying sorbents in controlled release formulations to prevent herbicides pollution

The herbicides chloridazon and metribuzin, identified as groundwater pollutants, were incorporated in alginate-based granules to obtain controlled release properties. In this research the effect of incorporation of sorbents such as bentonite, anthracite and activated carbon in alginate basic formulation were not only studied on encapsulation efficiency but also on the release rate of herbicides which was studied using water release kinetic tests. In addition, sorption studies of herbicides with bentonite, anthracite and activated carbon were made. The kinetic experiments of chloridazon and metribuzin release in water have shown that the release rate is higher in metribuzin systems than in those prepared with chloridazon, which has lower water solubility. Besides, it can be deduced that the use of sorbents reduces the release rate of the chloridazon and metribuzin in comparison to the technical product and to the alginate formulation without sorbents. The highest decrease in release rate corresponds to the formulations prepared with activated carbon as a sorbent. The water uptake, permeability, and time taken for 50% of the active ingredient to be released into water, T(50), were calculated to compare the formulations. On the basis of a parameter of an empirical equation used to fit the herbicide release data, the release of chloridazon and metribuzin from the various formulations into water is controlled by a diffusion mechanism. Sorption capacity of the sorbents for chloridazon and metribuzin, ranging from 0.53mgkg(-1) for the metribuzin sorption on bentonite to 2.03x10(5)mgkg(-1) for the sorption of chloridazon on the activated carbon, was the most important factor modulating the herbicide release.