bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geographic selection bias of occurrence data influences transferability of invasiveHydrilla verticillatadistribution models
Authors: Barnes Matthew A. , Jerde Christopher L. , Wittmann Marion E. , Chadderton W. Lindsay , Ding Jianqing , Zhang Jialiang , Purcell Matthew , Budhathoki Milan , Lodge David M. 
Published: May 2014

AbstractDue to socioeconomic differences, the accuracy and extent of reporting on the occurrence of native species differs among countries, which can impact the performance of species distribution models. We assessed the importance of geographical biases in occurrence data on model performance usingHydrilla verticillataas a case study. We used Maxent to predict potential North American distribution of the aquatic invasive macrophyte based upon training data from its native range. We produced a model using all available native range occurrence data, then explored the change in model performance produced by omitting subsets of training data based on political boundaries. We also compared those results with models trained on data from which a random sample of occurrence data was omitted from across the native range. Although most models accurately predicted the occurrence ofH. verticillatain North America (AUC > 0.7600), data omissions influenced model predictions. Omitting data based on political boundaries resulted in larger shifts in model accuracy than omitting randomly selected occurrence data. For well‐documented species likeH. verticillata, missing records from single countries or ecoregions may minimally influence model predictions, but for species with fewer documented occurrences or poorly understood ranges, geographic biases could misguide predictions. Regardless of focal species, we recommend that future species distribution modeling efforts begin with a reflection on potential spatial biases of available occurrence data. Improved biodiversity surveillance and reporting will provide benefit not only in invaded ranges but also within under‐reported and unexplored native ranges.
Trends in prevalence from 1990 to 2007 of patients hospitalized with heart failure in Sweden
Authors: Parén Pär , Schaufelberger Maria , Björck Lena , Lappas Georgios , Fu Michael , Rosengren Annika 
Published: May 2014

AimsTo investigate trends in absolute numbers and prevalence from 1990 to 2007 of patients hospitalized with heart failure (HF) in Sweden.Methods and resultsNational inpatient and cause‐specific death registers were used to calculate age‐ and sex‐specific trends in absolute numbers and prevalence from 1990 to 2007 of patients hospitalized with HF in Sweden. Absolute numbers increased from 105 449 in 1990 to 144 925 in 2007, with a 77% increase in patients aged 85–99 years. The overall age‐adjusted prevalence in 1990 was 1.73%, and this increased with an estimated annual percentage change (EAPC) of 4.3% [95% confidence interval (CI) 3.6–4.9%] from 1990 to 1995, with no further significant change until 2002. The single year with the highest prevalence was 1998, when it peaked at 2.13%. The prevalence then declined slowly from 2002 (EAPC –1.1, 95% CI −1.5% to −0.6%) to 1.99% in 2007. The decrease in prevalence was not found in persons <65 years, where, instead, an increase was found throughout the period.ConclusionFears of an impending HF ‘epidemic’ could not be confirmed in this analysis of trends in prevalence for the period 1990–2007 of patients hospitalized with HF in Sweden. An overall slight decrease in age‐adjusted prevalence was observed from 2002. The prevalence in patients <65 years increased markedly. In absolute numbers, there was a substantial increase among the very old, consistent with demographic changes.
Synthesis and Characterization of Dibenzoheterocycle‐Bridged Dinuclear Ruthenium Alkynyl and Vinyl Complexes
Authors: Zhang Jing , Ou Yaping , Xu Meng , Sun Chaofang , Yin Jun , Yu Guang‐Ao , Liu Sheng Hua 
Published: May 2014

AbstractA series of dinuclear ruthenium alkynyl and vinyl complexes bridged by carbazole, dibenzofuran, dibenzothiophene, and fluorenone have been prepared, and some representative molecular structures have been determined. The electrochemical and spectroscopic properties of the compounds were explored by cyclic voltammetry (CV), square‐wave voltammetry (SWV), and in situ infrared and UV/Vis/near‐IR spectroelectrochemical methods. The electrochemical results indicate that the greater the electron density on the ligand, the more stable the bridge‐based oxidation product and the larger the electrochemical splitting. The UV/Vis/near‐IR spectroelectrochemical studies revealed that the bridged ligands strongly contribute to or even dominate the oxidation processes. In addition, IR spectroelectrochemistry strengthens the theory of redox noninnocence in the bridging ligands, which was further confirmed by DFT calculations.
Gold‐Catalyzed Conversion of Aryl‐ and Alkyl‐Substituted 1‐(o‐Aminophenyl)‐2‐propyn‐1‐ones to the Corresponding 2‐Substituted 4‐Quinolones
Authors: Seppänen Otto , Muuronen Mikko , Helaja Juho 
Published: May 2014

AbstractGold‐catalyzed cyclization of alkyl‐ or aryl‐substituted 1‐(o‐aminophenyl)‐2‐propyn‐1‐ones to the corresponding 2‐substituted 4‐quinolones was studied with various gold salts and complexes. Screening of the different catalysts showed highest performance with cationic AuI species. In particular PPh3AuNTf2 complex was the most efficient catalyst. Relative to classic quinolone synthesis that requires harsh cyclocondensation conditions, the current method offers a mild and atom‐economic alternative. Mechanistically, DFT studies at TPSS‐D3/def2‐TZVP level suggest that gold operates in an alkynophilic manner rather than through conjugative carbonyl activation.
Crew variability in topographic surveys for monitoring wadeable streams: a case study from the Columbia River Basin
Authors: Bangen Sara , Wheaton Joe , Bouwes Nicolaas , Jordan Chris , Volk Carol , Ward Michael B. 
Published: May 2014

ABSTRACTDigital elevation models (DEMs) derived from ground‐based topographic surveys have become ubiquitous in the field of fluvial geomorphology. Their wide application in spatially explicit analysis includes hydraulic modeling, habitat modeling, and morphological sediment budgeting. However, there is a lack of understanding regarding the repeatability and precision of DEMs derived from ground‐based surveys conducted by different, and inherently subjective, observers. This is of particular concern when we consider the proportion of studies and monitoring programs that are implemented across multiple sites and over time by different observers. We used a case study from the Columbia Habitat Monitoring Program (CHaMP), where seven field crews sampled the same six sites, to quantify the magnitude and effect of observer variability on DEMs interpolated from total station surveys. We quantified the degree to which DEM‐derived metrics and measured geomorphic change were repeatable. Across all six sites, we found an average elevation standard deviation of 0.05 m among surveys, and a mean total range of 0.16 m. A variance partition between site, crew, and unexplained errors for several topographically derived metrics showed that crew variability never accounted for > 1.5% of the total variability. We calculated minor geomorphic changes at one site following a relatively dry flow year between 2012 and 2011. Calculated changes were minimal (unthresholded net changes ±1–3 cm) with six crews detecting an indeterminate sediment budget and one crew detecting a minor net erosional sediment budget. While crew variability does influence the quality of topographic surveys, this study highlights that when consistent surveying methods are employed, the data sets are still sufficient to support derivation of topographic metrics and conduct basic geomorphic change detection. Copyright © 2014 John Wiley & Sons, Ltd.
Geomorphological factors predict water quality in boreal rivers
Authors: Varanka Sanna , Hjort Jan , Luoto Miska 
Published: May 2014

AbstractWater quality is the outcome of numerous landscape factors in the catchment. In addition to land use, soil deposits, bedrock and topography are central in different catchment processes and thus important in predicting water quality. In this study, we explored the influence of geomorphological factors at the catchment scale on water quality in 32 boreal rivers in Finland. Water quality was studied through total phosphorus, total nitrogen, pH and water colour, whereas geomorphological factors covered variables from topography, bedrock and surficial ground material (Quaternary soil deposits). Spearman's rank correlation test was used to study the correlations between variables. The relationship between water quality and geomorphology was analysed using novel multivariate methods by fitting of geomorphological vectors and smooth surfaces onto a non‐metric multidimensional scaling (NMDS) scattergram. Hierarchical partitioning (HP) was used to assess the relative importance of geomorphological variables on water quality.Quaternary soil deposits, especially the covers of clay‐silt and till soils, were important factors in relation to phosphorus and nitrogen based on both NMDS and HP analyses. For example, clay‐silt cover explained over 40% of the variation in these nutrients according to HP. The variation in river water pH was best explained by the covers of sand and open bedrock terrain as well as by catchment topography. Geomorphological variables differed in their effect and relative significance, and thus several geomorphological attributes need to be considered when examining variation in water quality. In conclusion, these results demonstrate that geomorphological factors can be used to predict physical–chemical water quality in a cost‐efficient manner in boreal rivers. NMDS was successfully applied in water quality analyses at the catchment scale. Copyright © 2014 John Wiley & Sons, Ltd.
Bioaccumulation and effects of different-shaped copper oxide nanoparticles in the deposit-feeding snail Potamopyrgus antipodarum
Authors: Ramskov Tina , Selck Henriette , Banta Gary , Misra Superb K. , Berhanu Deborah , Valsami-Jones Eugenia , Forbes Valery E. 
Published: May 2014

Abstract

Copper oxide (CuO) nanoparticles (NPs) are among the most widely used engineered NPs and are thus likely to end up in the environment, predominantly in sediments. Copper oxide NPs have been found to be toxic to a variety of (mainly pelagic) organisms, but to differing degrees. In the present study, the influence of CuO NP shape on bioavailability and toxicity in the sediment-dwelling freshwater gastropod Potamopyrgus antipodarum was examined. In 2 separate studies, snails were exposed to either clean sediment or sediment spiked with either aqueous Cu or CuO NPs of different shapes (rods, spheres, or platelets) at 240 µg Cu/g dry weight of sediment (nominal). In neither of the studies was survival found to be related to Cu form (i.e., free ion vs particle) or shape, whereas snail growth was severely influenced by both form and shape. Reproduction was affected (by CuO NP spheres and aqueous Cu) only when estimated as the total number (live plus dead) of juveniles produced per snail per week. Both the aqueous and particulate forms of Cu were available for uptake by snails when mixed into sediment. However, Cu body burden was not directly related to observed effects. The present study stresses the need for both a better understanding of uptake mechanisms and internal distribution pathways of NPs and an assessment of long-term consequences of NP exposure. Environ Toxicol Chem 2014; 33:1976–1987. © 2014 SETAC
Determination of soil–water sorption coefficients of volatile methylsiloxanes
Authors: Kozerski Gary E. , Xu Shihe , Miller Julie , Durham Jeremy 
Published: May 2014

Abstract

The sorption behaviors of 4 cyclic and linear volatile methyl siloxane (VMS) compounds between water and organic matter in 3 United Kingdom soils were studied by a batch equilibrium method using13C-enriched sorbates. Sorption and desorption kinetics and isotherms were determined for octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), octamethyltrisiloxane (L3), and decamethyltetrasiloxane (L4). Concentrations of [13C]-VMS in the soil and aqueous phases were measured directly by extraction and gas chromatography–mass spectrometry techniques. All VMS compounds were sorbed rapidly, reaching constant distributions in all soils by 24 h. Desorption kinetics were very rapid, with reattainment of equilibrium within 1 h. In the main, linear isotherms were observed for aqueous concentrations at or below 4% of the solubility limits. The average sorption organic carbon partition coefficient (log KOC) values across soils were 4.23 for D4, 5.17 for D5, 4.32 for L3, and 5.13 for L4, with standard deviations of 0.09 to 0.34. Desorption KOC values were systematically greater by 0.1 log units to 0.3 log units. The linear isotherms and low variation in KOC values across soils suggested partitioning-dominated sorption of the VMS. Compared with traditional hydrophobic organic compounds, KOC values for the VMS compounds were significantly lower than expected on the basis of their octanol–water partition coefficients. A linear free energy relationship analysis showed that these differences could be rationalized quantitatively in terms of the inherent characteristics of the VMS compounds, combined with the differences in solvation properties of organic matter and octanol. Environ Toxicol Chem 2014; 33:1937–1945. © 2014 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.
The use of assemblage models to describe trace element partitioning, speciation, and fate: A review
Authors: Groenenberg Jan E. , Lofts Stephen 
Published: May 2014

Abstract

The fate of trace elements in soils, sediments, and surface waters is largely determined by their binding to reactive components, of which organic matter, metal oxides, and clays are considered most important. Assemblage models, combining separate mechanistic complexation models for each of the reactive components, can be used to predict the solid-solution partitioning and speciation of trace elements in natural environments. In the present review, the authors provide a short overview of advanced ion-binding models for organic matter and oxides and of their application to artificial and natural assemblages. Modeling of artificial assemblages of mineral components and organic matter indicates that the interactions between organic and mineral components are important for trace element binding, particularly for oxyanions. The modeling of solid-solution partitioning in natural systems is generally adequate for metal cations but less so for oxyanions, probably because of the neglect of organic matter–oxide interactions in most assemblage models. The characterization of natural assemblages in terms of their components (active organic matter, reactive oxide surface) is key to successful model applications. Improved methods for characterization of reactive components in situ will enhance the applicability of assemblage models. Collection of compositional data for soil and water archetypes, or the development of relationships to estimate compositions from geospatially available data, will further facilitate assemblage model use for predictive purposes. Environ Toxicol Chem 2014;33:2181–2196. © 2014 SETAC
Delineating ion-ion interactions by electrostatic modeling for predicting rhizotoxicity of metal mixtures to lettuce Lactuca sativa
Authors: Le T. T. Yen , Wang Peng , Vijver Martina G. , Kinraide Thomas B. , Hendriks A. Jan , Peijnenburg Willie J.G.M. 
Published: May 2014

Abstract

Effects of ion–ion interactions on metal toxicity to lettuce Lactuca sativa were studied based on the electrical potential at the plasma membrane surface (ψ0). Surface interactions at the proximate outside of the membrane influenced ion activities at the plasma membrane surface ({Mn+}0). At a given free Cu2+ activity in the bulk medium ({Cu2+}b), additions of Na+, K+, Ca2+, and Mg2+ resulted in substantial decreases in {Cu2+}0. Additions of Zn2+ led to declines in {Cu2+}0, but Cu2+ and Ag+ at the exposure levels tested had negligible effects on the plasma membrane surface activity of each other. Metal toxicity was expressed by the {Mn+}0–based strength coefficient, indicating a decrease of toxicity in the order: Ag+ &gt; Cu2+ &gt; Zn2+. Adsorbed Na+, K+, Ca2+, and Mg2+ had significant and dose-dependent effects on Cu2+ toxicity in terms of osmolarity. Internal interactions between Cu2+ and Zn2+ and between Cu2+ and Ag+ were modeled by expanding the strength coefficients in concentration addition and response multiplication models. These extended models consistently indicated that Zn2+ significantly alleviated Cu2+ toxicity. According to the extended concentration addition model, Ag+ significantly enhanced Cu2+ toxicity whereas Cu2+ reduced Ag+ toxicity. By contrast, the response multiplication model predicted insignificant effects of adsorbed Cu2+ and Ag+ on the toxicity of each other. These interactions were interpreted using ψ0, demonstrating its influence on metal toxicity. Environ Toxicol Chem 2014; 33:1988–1995. © 2014 SETAC
MOSAIC_SSD: A new web tool for species sensitivity distribution to include censored data by maximum likelihood
Authors: Kon Kam King Guillaume , Veber Philippe , Charles Sandrine , Delignette-Muller Marie Laure 
Published: May 2014

Abstract

Censored data are seldom taken into account in species sensitivity distribution (SSD) analysis. However, they are found in virtually every dataset and sometimes represent the better part of the data. Stringent recommendations on data quality often entail discarding a lot of these meaningful data, resulting in datasets of reduced size which lack representativeness of any realistic community. However, it is reasonably simple to include censored data in SSD by using an extension of the standard maximum likelihood method. The authors detail this approach based on the use of the R-package fitdistrplus, dedicated to the fit of parametric probability distributions. The authors present the new Web tool MOSAIC_SSD, that can fit an SSD on datasets containing any type of data, censored or not. The MOSAIC_SSD Web tool predicts any hazardous concentration and provides bootstrap confidence intervals on the predictions. Finally, the authors illustrate the added value of including censored data in SSD, taking examples from published data. Environ Toxicol Chem 2014; 33:2133–2139. © 2014 SETAC
Activity and ecological implications of maize-expressed transgenic endo-1,4-β-D-glucanase in agricultural soils
Authors: Kenny Adam J. , Wolt Jeffrey D. 
Published: May 2014

Abstract

Plant expression of thermostable endoglucanase (E1) has been proposed for improved conversion of lignocellulose to ethanol for fuel production. Residues of E1-expressing maize may affect ecological services (e.g., C mineralization and biogeochemical cycling) on soils where they occur. Therefore, the activity of residual E1 was investigated using soils amended with bacterial and plant-solubilized E1 compared with soil endogenous activity and residual activity from a mesostable cellulase (Aspergillus and Trichoderma spp.). An optimized analytical method involving a carboxymethyl cellulose substrate and dinitrosalicylic acid detection effectively assayed endoglucanase activity in amended and unamended soils and was used for determining E1 activity in 3 representative soils. The effect of E1 on soil carbon mineralization was determined by comparing CO2 evolution from soils amended with transgenic E1-expressing and wild-type maize tissue. Extraction and recovery of the mesostable comparator, bacterial E1, and plant-soluble E1 showed nearly complete loss of exogenous endoglucanase activity within a 24-h period. Carbon mineralization indicated no significant difference between soils amended with either the transgenic E1 or wild-type maize tissue. These results indicate that maize residues expressing up to 30 µg E1/g tissue negligibly affect soil endoglucanase activity and CO2 respiration for representative soils where transgenic E1 maize may be grown. Environ Toxicol Chem 2014; 33:1996–2003. © 2014 SETAC
Characteristic and potential sources of polychlorinated dibenzo-p-dioxins and dibenzofurans in agricultural soils in Beijing, China
Authors: Li Wei , Li Chaoqin , Chen Zuosheng , Cai Zongwei 
Published: May 2014

Abstract

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed in 25 background and 80 agricultural soil samples collected from 21 sites in Beijing, China. The levels of PCDD/Fs in the north agricultural soils were low (0.15–0.58 ng international toxic equivalent quantity [I-TEQ]/kg), which were comparable with those of the background soils (0.091–0.35 ng I-TEQ/kg). In the southern agricultural soils, however, concentrations were several times higher (0.27–3.3 ng I-TEQ/kg). Comparison of PCDD/Fs congener compositions between possible sources and samples indicated that agricultural soils in Beijing had not been contaminated by the 3 main PCDD/F contamination sources in China—ferrous and nonferrous metal, waste incineration, and power generation. They had, however, been slightly contaminated by the impurities of some organochlorine pesticides, such as sodium pentachlorophenate, and by open burning of biomass, vehicle exhaust, atmospheric deposition, sediment, and sewage sludge. These results have been supported by the principal components analysis. Environ Toxicol Chem 2014; 33:2004–2012. © 2014 SETAC
Amygdala task‐evoked activity and task‐free connectivity independently contribute to feelings of arousal
Authors: Touroutoglou Alexandra , Bickart Kevin C. , Barrett Lisa Feldman , Dickerson Bradford C. 
Published: May 2014

AbstractIndividual differences in the intensity of feelings of arousal while viewing emotional pictures have been associated with the magnitude of task‐evoked blood‐oxygen dependent (BOLD) response in the amygdala. Recently, we reported that individual differences in feelings of arousal are associated with task‐free (resting state) connectivity within the salience network. There has not yet been an investigation of whether these two types of functional magnetic resonance imaging (MRI) measures are redundant or independent in their relationships to behavior. Here we tested the hypothesis that a combination of task‐evoked amygdala activation and task‐free amygdala connectivity within the salience network relate to individual differences in feelings of arousal while viewing of negatively potent images. In 25 young adults, results revealed that greater task‐evoked amygdala activation and stronger task‐free amygdala connectivity within the salience network each contributed independently to feelings of arousal, predicting a total of 45% of its variance. Individuals who had both increased task‐evoked amygdala activation and stronger task‐free amygdala connectivity within the salience network had the most heightened levels of arousal. Task‐evoked amygdala activation and task‐free amygdala connectivity within the salience network were not related to each other, suggesting that resting‐state and task‐evoked dynamic brain imaging measures may provide independent and complementary information about affective experience, and likely other kinds of behaviors as well. Hum Brain Mapp 35:5316–5327, 2014. © 2014 Wiley Periodicals, Inc.