The role of respondents’ comfort for variance in stated choice surveys: evidence from a SCUBA diving case

Preference elicitation among outdoor recreational users is subject to measurement errors that depend, in part, on survey planning. This study uses data from a choice experiment survey on recreational SCUBA diving to investigate whether self-reported information on respondents’ comfort when they complete surveys correlates with the error variance in stated choice models of their responses. Comfort-related variables are included in the scale functions of the scaled multinomial logit models. The hypothesis was that higher comfort reduces error variance in answers, as revealed by a higher scale parameter and vice versa. Information on, e.g., sleep and time since eating (higher comfort) correlated with scale heterogeneity, and produced lower error variance when controlled for in the model. That respondents’ comfort may influence choice behavior suggests that knowledge of the respondents’ activity patterns could be used to plan the timing of interviews to decrease error variance in choices and, hence, generate better information.     

Development of an enzyme-linked immunosorbent assay for atrazine monitoring in water samples

The implementation of the Water Framework Directive (2000/60/EC) requires the establishment of monitoring programs. However, conventional procedures for sample preparation prior to chromatographic analysis are rather expensive and time consuming, being the development of cost-effective and easy tool a necessity. The aim of this work was to develop an enzyme-linked immunosorbent assay (ELISA) able to determine atrazine in water samples. Matrix effects evaluation showed that the increase of humic acid (HA) concentration leads to flattened calibration curves and to the loss of the sigmoidal shape. However, such interference was overcome, by the presence of an environmental sample buffer, incubated together with the samples. Recoveries from 88.5 to 119.2 % were obtained in the presence of HA concentrations up to 20 mg?L^?1. An analytical range from 0.003 to 1 μg?L^?1 was obtained, and atrazine was detected in a sewage treatment plant with concentrations ranging from 14 to 52 ng?L^?1.     

A systematic review of biodiversity and demographic change: A misinterpreted relationship?

Demographic change is supposed to be the most important indirect driver for changing biodiversity. In this article, a systematic review of 148 studies was conducted to examine the scientific evidence for this relationship and to identify potential gaps in research. We explored the spatial distribution of studies, the categories addressed with respect to biodiversity and demographic change, and the ways in which their relationships were conceptualised (spatially and temporally) and valued. The majority of studies were carried out in Africa, Europe and North America. Our analysis confirms the trend that demographic phenomena were mostly found to negatively influence biodiversity. However, a considerable number of studies also point towards impacts that were context dependent, either positive or negative under certain circumstances. In addition to that we identified significant gaps in research. In particular, there is a lack of addressing (1) other demographic aspects such as population decline, age structure or gender differences, (2) spatial variability of, e.g. human population growth, (3) long-term effects of demographic processes, and (4) the context dependency (e.g. regulations/law enforcement, type of human activities, and choice of scale or proxy). We conclude there is evidence that the relationship between biodiversity and demographic change is much more complex than expected and so far represented in research. Thus, we call for a social–ecological biodiversity research that particularly focusses on the functional relation between biodiversity and human activities, namely the different types, context, and interdependent dynamics (spatial and temporal) of this complex relation.

     

Synthesis of Gum Acacia Capped Polyaniline-Based Nanocomposite Hydrogel for the Removal of Methylene Blue Dye

In this research work, a novel gum acacia capped polyaniline-based nanocomposite hydrogel (GPA NCHs) was developed and evaluated for the adsorptive removal of cationic methylene blue dye (MB) from aqueous solutions. Firstly, Gum acacia (GA) capped Polyaniline (PANI) dispersion was synthesized by using dispersion polymerization. Then, a water-swellable hydrogel network consisting of GA-PANI and acrylamide (AM) was obtained by using N,N′ -methylene-bisacrylamide (MBA) as a cross-linker, and ammonium persulphate/N,N,N′,N′-tetramethylethylenediamine (APS/TMEDA) as an initiating system. The developed materials were characterized by UV–visible, FTIR, XRD, SEM–EDX and TEM techniques. The microscopy studies revealed that GA-PANI nanoparticles have a granular morphological surface with an average size of?~?40–100 nm. Removal of MB dye from aqueous system was performed by adsorption studies in batch equilibrium mode with different dosage of GA-PANI, MB concentration, pH and temperatures. The adsorption data revealed that the absorption capacity of GPA NCHs highly depends on the dosage of GA-PANI, pH and concentration of the MB dye. The maximum percentage of MB removal onto GPA 1.0 NCHs was found to be 89% at pH 10 with a dye concentration of 10 mg L^?1. The equilibrium adsorption data were also analyzed by different models to understand the adsorption process. The results revealed that the adsorption process followed the pseudo-second-order kinetics and it fit well in Langmuir and Freundlich adsorption isotherms with a maximum adsorption capacity of 35.41 mg g^?1. These studies demonstrate that the GPA NCHs could be a promising adsorbent material for the removal of MB dye from contaminated aqueous systems.

     

Distribution and correlation of radon and uranium and associated hydrogeochemical processes in alluvial aquifers of northwest India

Environmental Science and Pollution Research - The spatial and vertical distributions of radon and uranium are evaluated in relation to the hydrogeology, geomorphology, and hydrochemistry of...     

Long-term declines of European insectivorous bird populations and potential causes

Evidence of declines in insect populations has recently received considerable scientific and societal attention. However, the lack of long-term insect monitoring makes it difficult to assess whether declines are geographically widespread. By contrast, bird populations are well monitored and often used as indicators of environmental change. We compared the population trends of European insectivorous birds with those of other birds to assess whether patterns in bird population trends were consistent with declines of insects. We further examined whether declines were evident for insectivores with different habitats, foraging strata, and other ecological preferences. Bird population trends were estimated for Europe (1990–2015) and Denmark (1990–2016). On average, insectivores declined over the study period (13% across Europe and 28% in Denmark), whereas omnivores had stable populations. Seedeaters also declined (28% across Europe; 34% in Denmark), but this assessment was based on fewer species than for other groups. The effects of insectivory were stronger for farmland species (especially grassland species), for ground feeders, and for cold-adapted species. Insectivory was associated with long-distance migration, which was also linked to population declines. However, many insectivores had stable populations, especially habitat generalists. Our findings suggest that the decline of insectivores is primarily associated with agricultural intensification and loss of grassland habitat. The loss of both seed and insect specialists indicates an overall trend toward bird communities dominated by diet generalists.     

Deficiency of essential elements in volcanic soils: potential harmful health effects on grazing cattle

Environmental Geochemistry and Health - Several essential nutrients such as Fe, Co, Cu, I, Se, and Zn are vital to grazing cattle as they play a significant role in intracellular enzyme systems,...     

Social vulnerability to climate change: a review of concepts and evidence

Regional Environmental Change - This article provides a review of recent scientific literature on social vulnerability to climate change, aiming to determine which social and demographic groups,...