bluuebunny/crossref_metadata_2025_split huggingface dataset:
At the Whim of the State: Neoliberalism and Nongovernmental Organizations in Guerrero, Mexico
Authors: Yaworsky William R. 
Published: October 2005

This paper examines the relationship between the Secretaría de Desarrollo Social (SEDESOL) and nongovernmental organizations (NGOs) in the Chilapa region of Guerrero, Mexico. I argue that the Mexican state via SEDESOL has effectively harnessed NGOs to perform as regional pillars of neoliberal reform initiatives. The intimacy of this relationship raises serious questions for those who see NGOs performing as vehicles for furthering local or regional "autonomy." Instead, I argue that regional NGOs are key role players in the deepening incorporation of communities into the global industrial economy.Este artículo examina las relaciones entre la Secretaría de Desarrollo Social (SEDESOL) y las organizaciones no-gubernamentales (ONGs) en la región de Chilapa, Guerrero, en México. A lo largo del texto, demuestro que el Estado Mexicano y SEDESOL utilizan ONGs para que éstas funcionen como pilares del programa neoliberal en la región. Esto contradice la función de las ONGs como instancias que permiten a las comunidades rurales obtener más autonomía. En los hechos, empero, y según lo sostengo, las ONGs de la región fundan bases importantes de la economía capitalista global.
An evaluation of logistic regression models for predicting amphipod toxicity from sediment chemistry
Authors: Wetherington Jeffrey D. , Stanley Bruce H. , Adams Kathleen O. , Schwer Richard F. 
Published: October 2005

Abstract
An empirical screening level approach was developed to assess the probability of toxicity to benthic organisms associated with contaminated sediment exposure. The study was based on simple logistic regression models (LRMs) of matching sediment chemistry and toxicity data retrieved from a large database of field-collected sediment samples contaminated with multiple chemicals. Three decisions were made to simplify the application of LRMs to sediment samples contaminated with multiple chemicals. First, percent mortality information associated with each sediment sample was condensed into a dichotomous response (i.e., toxic or nontoxic). Second, each LRM assumed that toxicity was attributable to a single contaminant. Third, individual contaminants present at low concentrations were excluded from toxic sediment samples. Based on an analysis of the National Sediment Inventory database, the LRM approach classified 55% of nontoxic sediments as toxic (i.e., false-positives). Because this approach has been used to assess the probability of benthic toxicity as reported by the U.S. Environmental Protection Agency (U.S. EPA), the resultant estimates of potential toxicity convey a misleading impression of the increased hazard that sediments pose to the health of aquatic organisms at many sites in the United States. This could result in important resources needlessly being diverted from truly contaminated sites to evaluate and possibly remediate sediments at uncontaminated sites.
Predicting sediment metal toxicity using a sediment biotic ligand model: methodology and initial application
Authors: Di Toro Dominic M. , McGrath Joy A. , Hansen David J. , Berry Walter J. , Paquin Paul R. , Mathew Rooni , Wu Kuen Benjamin , Santore Robert C. 
Published: October 2005

Abstract
An extension of the simultaneously extracted metals/acid-volatile sulfide (SEM/AVS) procedure is presented that predicts the acute and chronic sediment metals effects concentrations. A biotic ligand model (BLM) and a pore water—sediment partitioning model are used to predict the sediment concentration that is in equilibrium with the biotic ligand effects concentration. This initial application considers only partitioning to sediment particulate organic carbon. This procedure bypasses the need to compute the details of the pore-water chemistry. Remarkably, the median lethal concentration on a sediment organic carbon (OC)—normalized basis, SEM*x,OC, is essentially unchanged over a wide range of concentrations of pore-water hardness, salinity, dissolved organic carbon, and any other complexing or competing ligands. Only the pore-water pH is important. Both acute and chronic exposures in fresh- and saltwater sediments are compared to predictions for cadmium (Cd), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) based on the Daphnia magna BLM. The SEM*x,OC concentrations are similar for all the metals except cadmium. For pH = 8, the approximate values (μmol/gOC) are Cd-SEM*x,OC ⋍ 100, Cu-SEM*x,OC ⋍ 900, Ni-SEM*x,OC ⋍ 1,100, Zn-SEM*x,OC ⋍ 1,400, and Pb-SEM*x,OC ⋍ 2,700. This similarity is the explanation for an empirically observed dose—response relationship between SEM and acute and chronic effects concentrations that had been observed previously. This initial application clearly demonstrates that BLMs can be used to predict toxic sediment concentrations without modeling the pore-water chemistry.
Significance testing of synergistic/antagonistic, dose level-dependent, or dose ratio-dependent effects in mixture dose-response analysis
Authors: Jonker Martijs J. , Svendsen Claus , Bedaux Jacques J.M. , Bongers Marina , Kammenga Jan E. 
Published: October 2005

Abstract
In ecotoxicology, the state of the art for effect assessment of chemical mixtures is through multiple dose—response analysis of single compounds and their combinations. Investigating whether such data deviate from the reference models of concentration addition and/or independent action to identify overall synergism or antagonism is becoming routine. However, recent data show that more complex deviation patterns, such as dose ratio—dependent deviation and dose level—dependent deviation, need to be addressed. For concentration addition, methods to detect such deviation patterns exist, but they are stand-alone methods developed separately in literature, and conclusions derived from these analyses are therefore difficult to compare. For independent action, hardly any methods to detect such deviations from this reference model exist. This paper describes how these well-established mixture toxicity principles have been incorporated in a coherent data analysis procedure enabling detection and quantification of dose level—and dose ratio—specific synergism or antagonism from both the concentration addition and the independent action models. Significance testing of which deviation pattern describes the data best is carried out through maximum likelihood analysis. This analysis procedure is demonstrated through various data sets, and its applicability and limitations in mixture research are discussed.
Effects of the polycyclic aromatic hydrocarbon heterocycles, carbazole and dibenzothiophene, on in vivo and in vitro cypia activity and polycyclic aromatic hydrocarbon-derived embryonic deformities
Authors: Wassenberg Deena M. , Nerlinger Abby L. , Battle Lauren P. , Di Giulio Richard T. 
Published: October 2005

Abstract
Herocyclic derivatives of polycyclic aromatic hydrocarbons (PAHs) are often significant components of environmental contaminant mixtures; however, their contribution to the toxicity of these mixtures is not well characterized. These heterocycles commonly co-occur in PAH mixtures, which contain agonists for the aryl hydrocarbon receptor (AHR). Our goal for these studies was to explore the effects of two PAH heterocycles, carbazole (CB) and dibenzothiophene (DBT), alone and in combination with a PAH-type agonist for the AHR (β-naphthoflavone [BNF]) on AHR-mediated cytochrome P4501A (CYP1A) activity and on fish embryotoxicity. Embryos of Fundulus heteroclitus were exposed to CB or DBT, with and without coexposure to BNF. Carbazole alone slightly induced, whereas DBT alone slightly reduced, in ovo CYP1A-mediated ethoxyresorufin-O-deethylase (EROD) activity compared to control values. However, exposure to CB or DBT reduced in ovo EROD activity in embryos coexposed to BNF. Carbazole and DBT were characterized in vitro as noncompetitive CYP1A inhibitors. Carbazole and DBT enhanced the embryotoxicity of BNF, although neither compound was embryotoxic by itself. The co-occurrence of CB and DBT with PAH-type AHR inducers in contaminated ecosystems may increase the toxicity of PAH-type AHR agonists in these settings and may need to be considered when estimating the embryotoxicity of PAH mixtures.
Correlation analyses for bimolecular nucleophilic substitution reactions of chloroacetanilide herbicides and their structural analogs with environmentally relevant nucleophiles
Authors: Lippa Katrice A. , Roberts A. Lynn 
Published: October 2005

Abstract
Second-order rate constants (kNuc) for aqueous-phase bimolecular nucleophilic substitution (SN2) reactions of a range of anionic nucleophiles with alachlor, propachlor, and two analogs of propachlor (a thioacetanilide and a β-anilide) were fit to the Swain-Scott and Edwards models. Correlations of literature kNuc values for analogous reactions of methyl chloride and methyl benzenesulfonate were included for comparison. The Swain-Scott correlation yielded poor to fair results for chloroacetanilides and their analogs, with adjusted (adj) r2 values ranging from 0.67 to 0.89, which are comparable to correlations for CH3Cl and CH3OSO2Ph (r2 (adj) = 0.80 and 0.85, respectively). Both the one- and two-parameter Edwards models yielded improved correlations for the majority of substrates. A pronounced dependence on the substrate polarizability (α) factor generally was observed for the Edwards model, with a negligible dependence on the substrate basicity (β) factor. Substrate polarizability factors for the one-parameter Edwards model were significantly larger for alachlor, propachlor, and the β-anilide analog of propachlor than for methyl chloride and methyl benzenesulfonate. This indicates that the chloroacetanilides are activated toward SN2 reactions with highly reactive nucleophiles (e.g., HS−, PhS−, and S2-n) relative to other saturated carbon substrates. At best, the Swain-Scott and Edwards models only furnish order-of-magnitude predictions of kNuc for the substrates investigated.
Application of frog embryo teratogenesis assay-Xenopus to ecological risk assessment
Authors: Hoke Robert A. , Ankley Gerald T. 
Published: October 2005

Abstract
An expert workshop recently was convened to consider the frog embryo teratogenesis assay-Xenopus (FETAX) as a screening method for identifying the potential developmental toxicity of single chemicals and chemical mixtures. One recommendation from the workshop was that, in order to determine the utility of FETAX for ecological risk assessments, additional consideration of how the assay is conducted is necessary. In addition, a comparative evaluation would be useful of FETAX endpoints (i.e., survival, malformations, growth) versus each other, endpoints from aquatic toxicity tests using more commonly tested species of cladocerans and fish, and tests with other amphibian species. This review provides an evaluation and critique of the current FETAX protocol from two perspectives: Practical considerations relative to conducting the test and sensitivity of the assay (and associated endpoints) compared to tests with other species. Several aspects of the current standard protocol, including test temperature, diet, loading rates, and chemical exposure options, need to be modified to ensure that the assay is robust technically. Evaluation of FETAX data from the open literature indicates that growth is the most sensitive endpoint in the assay, followed by malformations and then survival; unfortunately, the growth endpoint often is not considered or reported in the assay. Comparison of FETAX data with acute toxicity data from tests with other amphibians or traditional aquatic test species indicates FETAX is relatively insensitive. This suggests that environmental risk assessments using acute hazard data from tests with traditional aquatic test species usually would be more protective of native amphibian species than risk assessments that use hazard data from FETAX.
Validation of otolith growth rate analysis using cadmium-exposed larval topsmelt (Atherinops affinis)
Authors: Rose Wendy L. , Hobbs James A. , Nisbet Roger M. , Green Peter G. , Cherr Gary N. , Anderson Susan L. 
Published: October 2005

Abstract
We applied otolith growth rate analysis to an investigation of cadmium (Cd)-exposed larval topsmelt (Atherinops affinis) to determine if growth rate was a more sensitive measure than somatic growth (body wt or length). Topsmelt otoliths, calcareous concretions in the fish inner ear, formed daily increments, and otolith growth was proportional to somatic growth. Nine-day posthatch larval topsmelt were exposed to Cd (0–100 ppb) in seawater for 14 d and fed low or high ration levels in separate experiments. Whereas Cd impaired topsmelt growth and growth rates, the extent of growth reduction was dependent on the ration level. At high ration levels, otolith and somatic growth rates of fish exposed to Cd (50 and 100 ppb) were significantly reduced; however, no differences in final mean weight and only marginal differences in final mean length of Cd-exposed topsmelt were observed. At low ration levels, we detected reductions in both somatic growth as well as otolith and somatic growth rates of topsmelt exposed to Cd (50 and 100 ppb). Otolith growth rate analysis was more sensitive than growth measurements of Cd-exposed topsmelt, because it allowed the detection of small differences in growth rates even when differences in somatic growth were not observed.
Effects of polychlorinated biphenyls on the schooling behavior of Japanese medaka (Oryzias latipes)
Authors: Nakayama Kei , Oshima Yuji , Hiramatsu Kazuaki , Shimasaki Yohei , Honjo Tsuneo 
Published: October 2005

Abstract
The effects of polychlorinated biphenyls (PCBs; Kanechlor 400) on the schooling behavior of Japanese medaka (Oryzias latipes) were tested after feeding with various concentrations of PCBs (0, 1, 5, 25, and 125 μg/g). To test schooling, three PCB-exposed medaka and three untreated fish were placed in one chamber, and their swimming trajectories were recorded. Swimming velocity, turning angle, and nearest-neighbor distance (NND) were analyzed individually, and the polarization and expanse of each schooling group were analyzed. Fractal dimension analysis was performed for trajectory, swimming velocity, and turning angle. Six behaviors (school formed by six swimming medaka, school formed by six stationary medaka, school formed by three to five swimming medaka, school formed by three to five stationary medaka, swimming without schooling, and stationary without schooling) were quantified with time. Behavioral parameters were the same for PCB-exposed and unexposed medaka in the same schooling group. Swimming velocity decreased in a dose-dependent manner, and NND in the group exposed to 25 μg/g of PCBs was significantly longer (126%) than that in the controls. The fractal dimensions of trajectory and turning angle increased significantly in the highest PCB-exposure group, indicating that schools containing PCB-exposed individuals frequently changed direction. The PCBs shortened the time of school formed by six swimming fish, which was 23.7% of the control value in the group exposed to 25 μg/g of PCBs. The frequency of collisions between individuals was significantly greater in the highest-exposure group (31.3) than in the controls (13.3). Thus, PCB exposure influences the behavior of unexposed fish in the same school, consequently affecting schooling behavior.
Analysis of estrogenic effects by quantification of green fluorescent protein in juvenile fish of a transgenic medaka
Authors: Scholz Stefan , Kurauchi Kanta , Kinoshita Masato , Oshima Yuji , Ozato Kenjiro , Schirmer Kristin , Wakamatsu Yuko 
Published: October 2005

Abstract
The ChgH-GFP strain of the teleost medaka containsa regulatory region of the estrogen-responsive choriogenin H (chgH) gene fused to the green fluorescent protein (GFP) gene. The strain was developed for the identification of environmental estrogens by noninvasive analysis of GFP fluorescence. In the present study, a quantification method for GFP by image analysis was established and applied to the analysis of time-anmd d concentration-dependent GFP fluorescence in juvenile fish. Concentration-response analyses were performed with fish exposed for 14 d to 17β-estradiol (0.37–367 pM), genistein (0.37–367 nM), or p-nonylphenol (0.367–1,835 nM). By means of image analysis, it was shown that ChgH-GFP was induced at 183.5 pM or greater 17β-estradiol. Time-course and recovery experiments indicated a strong accumulation of GFP in the liver. Results of reverse transcriptase-polymerase chain reaction analysis of choriogenin H and vitellogenin demonstrated induction of gene expression for the same range of concentrations as that for GFP analysis. Neither expression of these genes nor GFP fluorescence was induced by genistein and p-nonylphenol. Although the ChgH-GFP strain failed to detect these weakly estrogenic compounds, the simplicity of the GFP quantification during early life stages of fish offers promising possibilities for further developments of transgenic strains using different target regulatory sequences.
Evaluation of microbial inoculation and vegetation to enhance the dissipation of atrazine and metolachlor in soil
Authors: Zhao Shaohan , Arthur Ellen L. , Moorman Thomas B. , Coats Joel R. 
Published: October 2005

Abstract
Four greenhouse studies were conducted to evaluate the effects of native prairie grasses and two pesticide-degrading bacteria to remediate atrazine and metolachlor in soils from agricultural dealerships (Alpha site soil, northwest Iowa, USA; Bravo site soil, central Iowa, USA). The Alpha soil contained a low population of atrazine-degrading microorganisms relative to the Bravo soil. Each soil freshly treated with atrazine or metolachlor was aged for a short or long period of time, respectively. An atrazine-degrading bacterium, Agrobacterium radiobacter strain J14a; a metolachlor-degrading bacterium, Pseudomonas fluorescens strain UA5–40; and a mixture of three native prairie grasses—big bluestem (Andropogon gerardii Vitman), yellow Indian grass (Sorghastrum nutans [L.] Nash), and switchgrass (Panicum virgatum L.)—were added to the soils after the soils were aged for long periods of time. The soils aged for short periods of time were treated with J14a, the prairie grasses, or both after aging. The J14a and the grasses significantly reduced the concentration of atrazine in Alpha soil when the soil was aged for a short period of time. However, these treatments had no statistically significant effect when the soil was aged for a long period of time or on atrazine in Bravo soil. Inoculation with UA5–40 did not enhance metolachlor dissipation in either soil, but vegetation did increase metolachlor dissipation. Our results indicate that the dissipation of atrazine by J14a is affected by the presence of indigenous atrazine-mineralizing microorganisms and probably by the bioavailability of atrazine in the soil.
Toxicity, biotransformation, and mode of action of arsenic in two freshwater microalgae (Chlorella sp. and Monoraphidium arcuatum)
Authors: Levy Jacqueline L. , Stauber Jennifer L. , Adams Merrin S. , Maher William A. , Kirby Jason K. , Jolley Dianne F. 
Published: October 2005

Abstract
The toxicity of As(V) and As(III) to two axenic topical freshwater microalgae, Chlorella sp. and Monoraphidium arcuatum, was determined using 72-h growth rate—inhibition bioassays. Both organisms were tolerant to As(III) (72-h concentration to cause 50% inhibition of growth rate [IC50], of 25 and 15 mg As[III]/L, respectively). Chlorella sp. also was tolerant to As(V) with no effect on growth rate over 72 h at concentrations up to 0.8 mg/L (72-h IC50 of 25 mg As[V]/L). Monoraphidium arcuatum was more sensitive to As(V) (72-h IC50 of 0.25 mg As[V]/L). An increase in phosphate in the growth medium (0.15–1.5 mg PO3-4/L) decreased toxicity, i.e., the 72-h IC50 value for M. arcuatum increased from 0.25 mg As(V)/L to 4.5 mg As(V)/L, while extracellular As and intracellular As decreased, indicating competition between arsenate and phosphate for cellular uptake. Both microalgae reduced As(V) to As(III) in the cell, with further biological transformation to methylated species (monomethyl arsonic acid and dimethyl arsinic acid) and phosphate arsenoriboside. Less than 0.01% of added As(V) was incorporated into algal cells, suggesting that bioaccumulation and subsequent methylation was not the primary mode of detoxification. When exposed to As(V), both species reduced As(V) to As(III); however, only M. arcuatum excreted As(III) into solution. Intracellular arsenic reduction may be coupled to thiol oxidation in both species. Arsenic toxicity most likely was due to arsenite accumulation in the cell, when the ability to excrete and/or methylate arsenite was overwhelmed at high arsenic concentrations. Arsenite may bind to intracellular thiols, such as glutathione, potentially disrupting the ratio of reduced to oxidized glutathione and, consequently, inhibiting cell division.
Electron paramagnetic resonance analysis of the distribution of a hydrophobic spin probe in suspensions of humic acids, hectorite, and aluminum hydroxide-humate-hectorite complexes
Authors: Spagnuolo Matteo , Jacobson Astrid R. , Baveye Philippe 
Published: October 2005

Abstract
Until recently, there were no techniques capable of direct observation of the microscale locations where nonpolar organic compounds accumulate when associated with natural geosorbents. The ability of electron paramagnetic resonance (EPR) spectroscopy to monitor and elucidate directly the different molecular-scale environments of paramagnetic spin probes has been demonstrated lately in model soils, yet it remains untested in complex systems. In this general context, the present investigation was aimed at assessing the extent to which EPR could be used to monitor the sorption of 4-hydroxy-2,2,6,6-tetramethyl-piperidinyloxy benzoate (TEMPO benzoate), a hydrophobic spin probe, on a smectite (hectorite), two humic acids, and their complexes in the presence or absence of aluminum hydroxide. Results demonstrate that EPR is able to monitor easily adsorption on these sorbents in batch-style experiments. Distribution coefficient (Kd) values of 455.4 and 483.1 ml/g were found for the adsorption of TEMPO benzoate on hectorite-humic acids complexes, compared to respective Kd values of 46 and 147 ml/g predicted solely on the basis of the mass of humic acids present in the complexes. These observations confirm the significant role of hectorite for the sorption of hydrophobic compounds, together with humic acids, contrary to common belief that emphasizes the almost exclusive sorptive role of organic matter. In addition, for the first time, EPR is able to provide evidence that hydrophobic molecules in the presence of geosorbents can segregate in multimolecular clusters that are in equilibrium with aqueous probe concentrations below the probe's solubility threshold. Possible consequences of this clustering process in terms of the fate and transport of hydrophobic compounds in subsurface environments are discussed.