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•Reline modified carbon paste electrodes presented superior performance.•EIS spectra showed lower Rct values for the reline modified carbon paste electrodes.•Glyceline, ethaline and ...reline were compared as binder modifying agents.•The DES electrode presented superior performance for oxidation of ascorbic acid.•The DES electrode presented superior performance for oxidation of dopamine.
This paper presents a new approach towards the modification of carbon paste electrodes with natural deep eutectic solvents (NADES) as a modified binder. The cyclic voltammograms with the NADES modified carbon paste electrode presented improved conductivity and charge transfer rate when compared to the bare carbon paste, evinced by the smaller peak potential separation. The incorporation of KCl solution into the NADES modifier reduced the binder layer viscosity, improving the diffusion of the probe to the graphite surface. The aforementioned effect is sustained by the reduction of the Rct values for graphite and the smaller value of the Gerischer parameter associated with the diffusion in thin layers. The reline modified carbon paste electrode also presented superior performance for the oxidation of dopamine and ascorbic acid, increasing the peak current values and reducing both the half peak width and potential peak separation for dopamine. Therefore, the results presented in this work are a first promising step of the application of NADES as a binder modifier that can be further enhanced with the modification of the modifying agent with molecular catalysts or nanomaterials.
Change in body size can be driven by social (density) and non-social (environmental and spatial variation) factors. In expanding metapopulations, spatial sorting by means of dispersal on the ...expansion front can further drive the evolution of body size. However, human intervention can dramatically affect these founder effects. Using long-term monitoring of the colonization of the remote Kerguelen islands by brown trout, a facultative anadromous salmonid, we analyse body size variation in 32 naturally founded and 10 human-introduced populations over 57 years. In naturally founded populations, we find that spatial sorting promotes slow positive changes in body size on the expansion front, then that body size decreases as populations get older and local density increases. This pattern is, however, completely different in human-introduced populations, where body size remains constant or even increases as populations get older. The present findings confirm that changes in body size can be affected by metapopulation expansion, but that human influence, even in very remote environments, can fully alter this process.
Natal dispersal is a key life history trait for the evolution and adaptation of wild populations. Although its evolution has repeatedly been related to the social and environmental context faced by ...individuals, parent-offspring regressions have also highlighted a possible heritable component. In this study, we explore heritability of natal dispersal, at the scale of the sub-Antarctic Possession Island, for a large-scale foraging seabird, the Wandering albatross Diomedea exulans, exploiting a pedigree spanning over four decades and a maximum of four generations. The comparison of three different methods shows that heritability on the liability scale can vary drastically depending on the type of model (heritability from 6% to 86%), with a notable underestimation by restricted maximum likelihood animal models (6%) compared to Bayesian animal models (36%). In all cases, however, our results point to significant additive genetic variance in the individual propensity to disperse, after controlling for substantial effects of sex and natal colony. These results reveal promising evolutionary potential for short-scale natal dispersal, which could play a critical role for the long-term persistence of this species on the long run.
Choline chloride (ChCl) based binary and ternary deep eutectic solvents (DES) were evaluated for methylene green electropolymerization with oxalic acid (OA) and ethylene glycol (EG) as hydrogen bond ...donors. Binary DES ChCl:OA in molar ratios 1:1 and 2:1 and ChCl:EG 1:2 and ternary DES (tDES) in different molar ratios and percentages of water were evaluated. The highest polymer growth was in ChCl:OA:EG‐tDES with added water, that had a lower viscosity and higher ionic conductivity when associated with HCl as dopant. This enhanced the formation of more cation radicals and, consequently, more polymer formation. The PMG/MWCNT/GCE‐tDES sensor was successfully applied to the simultaneous determination of 5‐aminosalicylic acid (5‐ASA) and acetaminophen (APAP) by differential pulse voltammetry in the concentration range 2 µM ‐ 200 µM, with detection limits of 0.37 µM and 0.49 µM for 5‐ASA and APAP, respectively. The sensor demonstrated good repeatability, reproducibility and stability, and was successfully applied in pharmaceutical formulations.
This work presents for the first time the incorporation of graphene oxide/palladium nanoparticles composite into a carbon paste electrode and its application in the quantification of p‐nitrophenol, a ...very hazardous pollutant, in a synthetic wastewater sample. The composite presented a homogeneous particle distribution and narrow size distribution, averaging 4 nm. The resulting electrode presented improved shelf stability and prevented the adsorption of byproducts of p‐nitrophenol on the electrode surface, which is an advantage when compared to other sensors, due to the presence of the polymer polyvinylimidazole inside the graphene oxide matrix. This work also explores the performance of the proposed sensor among other dyes which can be present simultaneously in industrial wastewater and free water bodies.
In the search for new electrode materials, a composite based on acetylene black (AB) and a vegetable oil/MDI polyurethane (PU) was prepared, characterized and evaluated regarding its potentialities ...as a voltammetric electrode. The composites were prepared in different compositions in the 20–60 AB range (AB %, m/m) and characterized regarding morphology with SEM and optical microscopies, composition by thermogravimetry, hydrophobicity by contact angle measurements and conductivity by determining their ohmic resistance. When the composites are submitted to suitable pressure during curing of the agglutinant, these results revealed that it conducted current from 20% AB (m/m), lost mechanical resistance above 60% AB (m/m), and the best conductance were found with 60% AB (m/m). Electrochemical response was evaluated using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), chronocoulometry and flow injection analysis. These results indicated the 60% AB (m/m) as the best composition regarding voltammetric responses to Fe(CN6)3-/ Fe(CN6)4-. The resulting electrode also presented the highest electroactive area and presented a wide useful potential ranges in different electrolytic media. The new composite presents a lower charge transfer resistance when compared with glassy carbon. It also presented a suitable response to organic probes hydroquinone, neurotransmiter dopamine and to the endocrine disruptor bisphenol-A, considered an emerging pollutant. The sensor revealed to be also useful as an amperometric detector in FIA.
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The life history schedules of wild organisms have long attracted scientific interest, and, in light of ongoing climate change, an understanding of their genetic and environmental underpinnings is ...increasingly becoming of applied concern. We used a multi‐generation pedigree and detailed phenotypic records, spanning 18 years, to estimate the quantitative genetic influences on the timing of hibernation emergence in a wild population of Columbian ground squirrels (Urocitellus columbianus). Emergence date was significantly heritable h2 = 0.22 ± 0.05 (in females) and 0.34 ± 0.14 (in males), and there was a positive genetic correlation (rG = 0.76 ± 0.22) between male and female emergence dates. In adult females, the heritabilities of body mass at emergence and oestrous date were h2 = 0.23 ± 0.09 and h2 = 0.18 ± 0.12, respectively. The date of hibernation emergence has been hypothesized to have evolved so as to synchronize subsequent reproduction with upcoming peaks in vegetation abundance. In support of this hypothesis, although levels of phenotypic variance in emergence date were higher than oestrous date, there was a highly significant genetic correlation between the two (rG = 0.98 ± 0.01). Hibernation is a prominent feature in the annual cycle of many small mammals, but our understanding of its influences lags behind that for phenological traits in many other taxa. Our results provide the first insight into its quantitative genetic influences and thus help contribute to a more general understanding of its evolutionary significance.
The growing interest for studying questions in the wild requires acknowledging that eco‐evolutionary processes are complex, hierarchically structured and often partially observed or with measurement ...error. These issues have long been ignored in evolutionary biology, which might have led to flawed inference when addressing evolutionary questions. Hierarchical modelling (HM) has been proposed as a generic statistical framework to deal with complexity in ecological data and account for uncertainty. However, to date, HM has seldom been used to investigate evolutionary mechanisms possibly underlying observed patterns. Here, we contend the HM approach offers a relevant approach for the study of eco‐evolutionary processes in the wild by confronting formal theories to empirical data through proper statistical inference. Studying eco‐evolutionary processes requires considering the complete and often complex life histories of organisms. We show how this can be achieved by combining sequentially all life‐history components and all available sources of information through HM. We demonstrate how eco‐evolutionary processes may be poorly inferred or even missed without using the full potential of HM. As a case study, we use the Atlantic salmon and data on wild marked juveniles. We assess a reaction norm for migration and two potential trade‐offs for survival. Overall, HM has a great potential to address evolutionary questions and investigate important processes that could not previously be assessed in laboratory or short time‐scale studies.
Quantitative genetic analyses have been increasingly used to estimate the genetic basis of life-history traits in natural populations. Imperfect detection of individuals is inherent to studies that ...monitor populations in the wild, yet it is seldom accounted for by quantitative genetic studies, perhaps leading to flawed inference. To facilitate the inclusion of imperfect detection of individuals in such studies, we develop a method to estimate additive genetic variance and assess heritability for binary traits such as survival, using capture-recapture (CR) data. Our approach combines mixed-effects CR models with a threshold model to incorporate discrete data in a standard 'animal model' approach. We employ Markov chain Monte Carlo sampling in a Bayesian framework to estimate model parameters. We illustrate our approach using data from a wild population of blue tits (Cyanistes caeruleus) and present the first estimate of heritability of adult survival in the wild. In agreement with the prediction that selection should deplete additive genetic variance in fitness, we found that survival had low heritability. Because the detection process is incorporated, capture-recapture animal models (CRAM) provide unbiased quantitative genetics analyses of longitudinal data collected in the wild.
Coal fly ash (FA), an aluminum silicate by-product and environmental pollutant which is generated during the combustion of coal in coal-fired power stations, was used as an electrode modifier for the ...determination of Cd(II) in aqueous solutions. In this work, graphite/polyurethane-based composites containing different amounts of FA were prepared and characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) thermogravimetry (TGA), and derivative thermogravimetry (DTG). The graphite/polyurethane composite electrodes (GPUE), with and without FA modifier, were evaluated with regard to their performance as voltammetric electrodes in the determination of metallic cations, using Cd(II) as a probe. After optimizing solution and instrumental parameters affecting the peak current, a differential pulse anode stripping voltammetry (DPASV) procedure was developed for GPUE modified with 5% FA (m/m), resulting in a linear response for Cd(II) from 2.0 x 10
−7
to 1.0 x 10
−6
mol L
−1
with a detection limit (LOD) of 6.6 x 10
−8
mol L
−1
. Cd(II) was added to natural water samples and determined at the 10
−7
mol L
−1
level with a mean recovery of 99%. It was also extracted from exhausted rechargeable Ni-Cd batteries and diluted to ca. 0.2 µmol L
−1
and determined with the same electrode, with recoveries of 98.7% when compared to FAAS. These results serve as a proof of concept that FA is a useful electrode modifier.
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