bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new framework for modeling the migration of meandering rivers
Authors: Parker G. , Shimizu Y. , Wilkerson G. V. , Eke E. C. , Abad J. D. , Lauer J. W. , Paola C. , Dietrich W. E. , Voller V. R. 
Published: December 2010

AbstractMany models of river meander migration rely upon a simple formalism, whereby the eroding bank is cut back at a rate that is dictated by the flow, and the depositing bank then migrates passively in response, so as to maintain a constant bankfull channel width. Here a new model is presented, in which separate relations are developed for the migration of the eroding bank and the depositing bank. It is assumed that the eroding bank consists of a layer of fine‐grained sediment that is cohesive and/or densely riddled with roots, underlain by a purely noncohesive layer of sand and/or gravel. Following erosion of the noncohesive layer, the cohesive layer fails in the form of slump blocks, which armor the noncohesive layer and thereby moderate the erosion rate. If the slump block material breaks down or is fluvially entrained, the protection it provides for the noncohesive layer diminishes and bank erosion is renewed. Renewed bank erosion, however, rejuvenates slump block armoring. At the depositing bank, it is assumed that all the sediment delivered to the edge of vegetation due to the transverse component of sediment transport is captured by encroaching vegetation, which is not removed by successive floods. Separate equations describing the migration of the eroding and depositing banks are tied to a standard morphodynamic formulation for the evolution of the flow and bed in the central region of the channel. In this model, the river evolves toward maintenance of roughly constant bankfull width as it migrates only to the extent that the eroding bank and depositing bank ‘talk’ to each other via the medium of the morphodynamics of the channel center region. The model allows for both (a) migration for which erosion widens the channel, forcing deposition at the opposite bank, and (b) migration for which deposition narrows the channel forcing erosion at the opposite bank. Copyright © 2010 John Wiley & Sons, Ltd.
Rate of floodplain reworking in response to increasing storm‐induced floods, Squamish River, south‐western British Columbia, Canada
Authors: Bauch Gregory D. , Hickin Edward J. 
Published: December 2010

AbstractRelations among hydroclimatic and channel planform changes on Squamish River are presented for the period 1956–2007. Squamish River basin occupies 3600 km2 of mountainous terrain in south‐western British Columbia, about 50 km north of Vancouver. The magnitude, volume and duration of extreme floods (Q ≥ 1500 m3/s) exhibit respective temporal increases of 50, 450 and 300%. The increase in extreme floods is attributed to the intensification of late‐season (August–December) Pacific storms that have produced increases in precipitation amounts, intensity and duration of respectively 340, 200 and 200% over the same period. Changes in floodplain‐surface area calculated from the geographic information system (GIS) differencing of sequential large‐scale aerial photographs indicate that the rate of geomorphic change in Squamish River has accelerated during the 1980s to the mid‐1990s. Among four study reaches of varying planform, erosional, depositional and cumulative changes in floodplain surface‐area have rapidly increased. Channel‐change activity after 1980 has increased by a factor of two to six compared with the period prior to 1980. Erosion is currently outpacing deposition in the majority of study reaches. Although channel geometry generally exhibits no uniform pattern of response to the increase in extreme floods, the meandering reaches have straightened over the duration of the study period. The increase in the magnitude and duration of the annual flood appears to be the principal cause of this recent acceleration of channel change. Copyright © 2010 John Wiley & Sons, Ltd.
An evaluation of biotic ligand models predicting acute copper toxicity to Daphnia magna in wastewater effluent
Authors: Constantino Carlos , Scrimshaw Mark , Comber Sean , Churchley John 
Published: December 2010

Abstract
The toxicity of Cu to Daphnia magna was investigated in a series of 48-h immobilization assays in effluents from four wastewater treatment works. The assay results were compared with median effective concentration (EC50) forecasts produced by the HydroQual biotic ligand model (BLM), the refined D. magna BLM, and a modified BLM that was constructed by integrating the refined D. magna biotic ligand characterization with the Windermere humic aqueous model (WHAM) VI geochemical speciation model, which also accommodated additional effluent characteristics as model inputs. The results demonstrated that all the BLMs were capable of predicting toxicity by within a factor of two, and that the modified BLM produced the most accurate toxicity forecasts. The refined D. magna BLM offered the most robust assessment of toxicity in that it was not reliant on the inclusion of effluent characteristics or optimization of the dissolved organic carbon active fraction to produce forecasts that were accurate by within a factor of two. The results also suggested that the biotic ligand stability constant for Na may be a poor approximation of the mechanisms governing the influence of Na where concentrations exceed the range within which the biotic ligand stability constant value had been determined. These findings support the use of BLMs for the establishment of site-specific water quality standards in waters that contain a substantial amount of wastewater effluent, but reinforces the need for regulators to scrutinize the composition of models, their thermodynamic and biotic ligand parameters, and the limitations of those parameters. Environ. Toxicol. Chem. 2011; 30:852–860. © 2010 SETAC
Perfluorooctane sulfonic acid exposure increases cadmium toxicity in early life stage of zebrafish, Danio rerio
Authors: Kim Suyoung , Ji Kyunghee , Lee Sangwoo , Lee Jinyoung , Kim Jungkon , Kim Sunmi , Kho Younglim , Choi Kyungho 
Published: December 2010

Abstract
Exposure to perfluorooctane sulfonic acid (PFOS) is known to induce thyroid-related adverse effects in aquatic organisms. Because an antioxidant defense mechanism is one of the key functions of the thyroid gland, we examined whether preexposure to PFOS could disrupt thyroid function and enhance cadmium (Cd)-induced oxidative stress in fish. Zebrafish embryos were exposed to control or 0.5 mg/L PFOS for 7 d after fertilization and subsequently exposed to 0.038 mg/L of Cd2+ or a mixture of the PFOS and Cd for an additional 3 d until 10 d postfertilization (dpf). Survival rates, body length, messenger RNA (mRNA) expressions related to thyroid function and oxidative stress, the levels of thyroid hormones, and malondialdehyde and antioxidant enzyme activities were measured. Significant down-regulation of mRNAs related to thyroid function (thyroid hormone receptor-alpha [THRα], thyroid hormone receptor-beta [THRβ], hematopoietically expressed homeobox [hhex], and paired box gene 8 [pax8]) and decrease of throxine (T4) levels were observed in the PFOS preexposure group, suggesting that PFOS preexposure would influence the performance of thyroid gland in the later stages of life. Certain genes relative to oxidative stress, such as superoxide dismutase 1 (sod1) and heat shock protein 70 (hsp70), in the PFOS preexposure group were significantly up-regulated when the larvae were subsequently exposed to Cd or to the mixture of PFOS and Cd. Glutathione S-transferase activity and malondialdehyde levels of the PFOS-preexposed group were increased significantly by Cd exposure. Significant decrease of the survival rates and body length of fish were observed at 10 dpf among the larvae that were previously exposed to PFOS. These results suggest that preexposure to PFOS could affect antioxidant defense mechanisms and potentially increase the toxicity of Cd on mRNA expression and enzyme activity level responses, as well as on survival or growth of individuals. Environ. Toxicol. Chem. 2011; 30:870–877. © 2010 SETAC
Impact of nano titanium dioxide exposure on cellular structure of Anabaena variabilis and evidence of internalization
Authors: Cherchi Carla , Chernenko Tatyana , Diem Max , Gu April Z 
Published: December 2010

Abstract
The present study investigated the impact of nano titanium dioxide (nTiO2) exposure on the cellular structures of the nitrogen-fixing cyanobacteria Anabaena variabilis. Results of the present study showed that nTiO2 exposure led to observable alteration in various intracellular structures and induced a series of recognized stress responses, including production of reactive oxygen species (ROS), appearance and increase in the abundance of membrane crystalline inclusions, membrane mucilage layer formation, opening of intrathylakoidal spaces, and internal plasma membrane disruption. The production of total ROS in A. variabilis cells increased with increasing nTiO2 doses and exposure time, and the intracellular ROS contributed to only a small fraction (&lt;10%) of the total ROS measured. The percentage of cells with loss of thylakoids and growth of membrane crystalline inclusions increased as the nTiO2 dose and exposure time increased compared with controls, suggesting their possible roles in stress response to nTiO2, as previously shown for metals. Algal cell surface morphology and mechanical properties were modified by nTiO2 exposure, as indicated by the increase in cell surface roughness and shifts in cell spring constant determined by atomic force microscopy analysis. The change in cell surface structure and increase in the cellular turgor pressure likely resulted from the structural membrane damage mediated by the ROS production. Transmission electron microscopy (TEM) analysis of nTiO2 aggregates size distribution seems to suggest possible disaggregation of nTiO2 aggregates when in close contact with microbial cells, potentially as a result of biomolecules such as DNA excreted by organisms that may serve as a biodispersant. The present study also showed, for the first time, with both TEM and Raman imaging that internalization of nTiO2 particles through multilayered membranes in algal cells is possible. Environ. Toxicol. Chem. 2011; 30:861–869. © 2010 SETAC
Tissue-specific toxicological effects of cadmium in green mussels (Perna viridis): Nuclear magnetic resonance-based metabolomics study
Authors: Wu Huifeng , Wang Wen-Xiong 
Published: December 2010

AbstractToxicity tests for metals have traditionally focused on selected biomarkers to characterize the biological stress induced by metals in marine organisms. Here nuclear magnetic resonance (NMR)-based metabolomics, a system biology tool, was applied to the marine green mussel, Perna viridis, to investigate the toxicological effects of Cd in both digestive gland and adductor muscle tissues. After Cd exposure for either two or four weeks, there was no significant metabolic change in the mussels exposed to Cd at 2 µg/L. At 20 µg/L, there were major metabolite changes related to amino acids, osmolytes, and energy metabolites. Digestive gland tissue was more sensitive to Cd than adductor muscle tissue. The adductor muscle tissue showed elevated levels of glutamine, glutamate, and lactate, and reduced levels of branched chain amino acids, aspartate, phenylalanine, and tyrosine. Overall, four weeks of Cd exposure produced neurotoxicity and metabolic disturbances and disturbed osmoregulation. These results suggest that the adductor muscle tissue of mussels may be a suitable supplemental biomarker for exposure to toxicants. In addition, the results demonstrate that 1H-NMR-based metabolomic analysis can provide a systematic view of the toxicological effects of metals on mussels, suggesting that it might be employed to investigate the toxicological effects of other marine pollutants. Environ. Toxicol. Chem. 2011; 30:806–812. © 2010 SETAC
Matrix effect study in the determination of linear alkylbenzene sulfonates in sewage sludge samples
Authors: Cantarero Samuel , Zafra-Gómez Alberto , Ballesteros Oscar , Navalón Alberto , Vílchez José L , Verge Coral , De Ferrer Juan A 
Published: December 2010

Abstract
We propose a study of the matrix effect in the determination of linear alkylbenzene sulfonates (LAS) in sewage sludge samples. First, a rapid, selective and sensitive method is proposed. The method involves two stages: the extraction of the compound from the samples and analysis by liquid chromatography with fluorescence detection (LC-FLD). Three different techniques of extraction (microwave-assisted extraction, Soxhlet, and ultrasounds) were compared, and microwave-assisted extraction was selected as the best suited for our purpose. Microwave-assisted extraction allows reducing the extraction time (25 min compared with 12 h for conventional Soxhlet extraction) and solvent waste (25 ml of methanol compared with 200 ml for Soxhlet or more than 50 ml for the ultrasonic procedure). Absence of matrix effect was evaluated with two standards (2ØC8:0 and 2ØC16:0) that are not commercial; therefore, neither of them was detected in sewage sludge samples and they showed similar environmental behavior (adsorption and precipitation) to LAS (C11:0–C13.0), which allow us to evaluate the matrix effect. Validation was carried out by a recovery assay, and the method was applied to samples from different sources; therefore, they had different compositions. Environ. Toxicol. Chem. 2011; 30:813–818. © 2010 SETAC
How do the phq‐2, the phq‐9 perform in aging services clients with cognitive impairment?
Authors: Boyle Lisa L. , Richardson Thomas M. , He Hua , Xia Yinglin , Tu Xin , Boustani Malaz , Conwell Yeates 
Published: December 2010

AbstractObjectiveTo examine the performance of the Patient Health Questionnaire‐2 (PHQ‐2) and the PHQ‐9 in detecting current major depressive episode (MDE) in aging services care management clients who screen positive for cognitive impairment (CI).MethodsCross‐sectional observational study of 236 care management clients ages ≥60 years recruited from an Upstate NY aging services agency. The test characteristics of the PHQ‐2 and PHQ‐9 to screen for depression were calculated using the Structured Clinical Interview for DSM‐IV (SCID) to identify MDE (gold standard). CI was identified with the Six‐Item Screen (SIS).ResultsParticipants had a mean age of 77 years, 68% female, 16% non‐white, and 26% had less than a high school education. 16% of participants had CI identified by ≥2 errors on SIS. Of these, 41% had positive PHQ‐2 (scores ≥3), 43% had positive PHQ‐9 (scores ≥10), while 24% met criteria for MDE. In the sample with CI, the PHQ‐2, using a cutoff of 3, had sensitivity = 0.78, specificity = 0.71, and receiver operating characteristic (ROC) area under the curve (AUC) = 0.81, compared with 0.79, 0.82, and 0.88, respectively, for those without CI. In the sample with CI, the PHQ‐9, using a cutoff of 10, had sensitivity = 0.89, specificity = 0.71, and AUC = 0.85, compared with 0.85, 0.89, and 0.91, respectively, for those without CI.ConclusionsCognitive status should be considered when using the PHQ as a depression screener due to poorer specificity in seniors with CI. Copyright © 2010 John Wiley & Sons, Ltd.
Frequency and predictors of proxy‐confirmed post‐stroke cognitive complaints in lacunar stroke patients without major depression
Authors: Xiong Yun‐Yun , Wong Adrian , Mok Vincent C. T. , Tang Wai‐Kwong , Lam Wynnie W. M. , Kwok Timothy C. Y. , Chu Winnie C. W. , Chan Anne Y. Y. , Wong Lawrence K. S. 
Published: December 2010

AbstractObjectiveMany lacunar stroke patients complained of cognitive decline after stroke. This study aims to investigate the factors underlying post‐stroke cognitive complaints in these patients.MethodsSeventy‐five consecutive lacunar stroke patients without major depression were recruited for the study. Stroke severity was measured using NIHSS score and MRI was performed during the acute admission period. At 3 months, objective psychometric performance and depressive symptoms were assessed. Post‐stroke cognitive complaints were corroborated by a proxy. Using logistic regression we examined the contribution of demographic features, stroke severity, objective psychometric scores, depressive symptoms, and imaging features (white matter lesion volume and infarct measures) to post‐stroke cognitive complaints.ResultsThirty‐two (42.7%) patients had post‐stroke cognitive complaints. Patients with post‐stroke cognitive complaints had more depressive symptoms and worse psychometric performance than those without. In the multivariate logistic regression model, only the severity of depressive symptoms was independently associated with post‐stroke cognitive complaints.ConclusionsThis study suggests that post‐stroke cognitive complaints are frequent among lacunar stroke patients without major depression and are prominently determined by the subclinical depressive symptomatology. Copyright © 2010 John Wiley & Sons, Ltd.
Rivastigmine transdermal patch and capsule in Alzheimer's disease: influence of disease stage on response to therapy
Authors: Farlow Martin R. , Grossberg George T. , Meng Xiangyi , Olin Jason , Somogyi Monique 
Published: December 2010

AbstractObjectivesThe cholinesterase inhibitor rivastigmine is approved for the symptomatic treatment of mild to moderate Alzheimer's disease (AD). This exploratory, hypothesis‐forming analysis assessed response to rivastigmine according to severity of dementia at baseline.MethodsThis was a retrospective analysis of a large randomized, placebo‐controlled trial (ENA713D2320). AD patients treated with 9.5 mg/24 h rivastigmine patch, 17.4 mg/24 h rivastigmine patch, rivastigmine capsule (12 mg/day), or placebo were stratified according to baseline Mini‐Mental State Examination (MMSE) scores: ≥7 to ≤12 (severe disease), ≥13 to ≤15 (moderately severe), ≥16 to ≤18 (moderate), or ≥19 to ≤25 (mild to moderate). Changes from baseline at Week 24 on Alzheimer's Disease Assessment Scale–cognitive subscale (ADAS‐cog), Alzheimer's Disease Cooperative Study–Clinical Global Impression of Change (ADCS‐CGIC), and Alzheimer's Disease Cooperative Study–Activities of Daily Living (ADCS‐ADL) were assessed.ResultsBased on baseline MMSE scores, 141, 228, 333, and 348 patients had severe, moderately severe, moderate, and mild to moderate dementia. Worsening of ADAS‐cog, ADCS‐CGIC, and ADCS‐ADL scores in patients receiving placebo were greater in patients with more severe dementia. Significant improvementsversusplacebo were seen with rivastigmine patch and/or capsule on ADAS‐cog, ADCS‐CGIC, and ADCS‐ADL scores in patients with severe, moderately severe, and moderate AD (allp < 0.05). However, no significant improvements were seen in rivastigmine‐treated patients with mild to moderate AD.ConclusionsRivastigmine benefits AD patients across dementia stages. Similar to previous cholinesterase inhibitor studies, greatest treatment effects with rivastigmine patch and capsule were seen in patients with more advanced dementia, most likely driven by greater placebo decline in this population. Copyright © 2010 John Wiley & Sons, Ltd.
Comparison of passive fog gauges for determining fog duration and fog interception by a Puerto Rican elfin cloud forest
Authors: Holwerda F. , Bruijnzeel L. A. , Scatena F. N. 
Published: December 2010

AbstractBetween 5 March and 10 May 2001, the performance of three types of passive fog gauges (wire harp WH, standard fog collector SC and Juvik gauge JU) was compared at a wind‐exposed Puerto Rican elfin cloud forest site. The gauges were used to determine the timing and duration of fog, as well as fog‐induced crown drip using gauge to canopy conversions factors. The latter were calculated as the average ratio between throughfall, and fog collected by the respective gauges during periods with fog‐only and negligible evaporation loss. The fog gauges indicated very similar timing and fog duration, presumably because dense fog prevailed for 75–80% of the time whereas winds were generally sufficiently strong (4–5 m s−1) and from a nearly constant direction. Resulting gauge to canopy factors were 0·12 for WH and SC, and 0·10 for JU. Estimating fog interception by the elfin forest canopy using these conversion factors gave very similar values for the three gauge types (mean rates of 0·15 ± 0·01 mm h−1). Throughfall typically started about 5 h after the fog gauges indicated the beginning of a fog event. This time lag probably reflects the filling of the canopy storage capacity. Integrating the estimated fog interception rates over the time lag suggested an average value of 0·4 mm for the canopy storage capacity during fog‐only events. The present results are expected to apply to sites with comparable wind and fog conditions. Copyright © 2010 John Wiley & Sons, Ltd.
Using eddy covariance and stable isotope mass balance techniques to estimate fog water contributions to a Costa Rican cloud forest during the dry season
Authors: Schmid S. , Burkard R. , Frumau K. F. A. , Tobón C. , Bruijnzeel L. A. , Siegwolf R. , Eugster W. 
Published: December 2010

AbstractFog deposition, precipitation, throughfall and stemflow were measured in a windward tropical montane cloud forest near Monteverde, Costa Rica, for a 65‐day period during the dry season of 2003. Net fog deposition was measured directly using the eddy covariance (EC) method and it amounted to 1·2 ± 0·1 mm day−1 (mean ± standard error). Fog water deposition was 5–9% of incident rainfall for the entire period, which is at the low end of previously reported values. Stable isotope concentrations (δ18O and δ2H) were determined in a large number of samples of each water component. Mass balance‐based estimates of fog deposition were 1·0 ± 0·3 and 5·0 ± 2·7 mm day−1 (mean ± SE) when δ18O and δ2H were used as tracer, respectively. Comparisons between direct fog deposition measurements and the results of the mass balance model using δ18O as a tracer indicated that the latter might be a good tool to estimate fog deposition in the absence of direct measurement under many (but not all) conditions. At 506 mm, measured water inputs over the 65 days (fog plus rain) fell short by 46 mm compared to the canopy output of 552 mm (throughfall, stemflow and interception evaporation). This discrepancy is attributed to the underestimation of rainfall during conditions of high wind. Copyright © 2010 John Wiley & Sons, Ltd.