bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of remediation in a mine‐impacted river: metal trends over large spatial and temporal scales
Authors: Hornberger Michelle I. , Luoma Samuel N. , Johnson Michael L. , Holyoak Marcel
Published: August 2009

The effectiveness of mine‐waste remediation at the Clark Fork River Superfund site in western Montana, USA, was examined by monitoring metal concentrations in resident biota (caddisfly, Hydropsyche spp.) and bed sediment over a 19‐year period. Remediation activities began in 1990 and are ongoing. In the upper 45 km, reduced Cu and Cd concentrations at some sites were coincident with remediation events. However, for a period of three years, the decline in Cu and Cd directly below the treatment ponds was offset by high arsenic concentrations, suggesting that remediation for cations (e.g., Cu and Cd) mobilized anions such as arsenic. The impact of remediation in the middle and lower reaches was confounded by a significant positive relationship between metal bioaccumulation and stream discharge. High flows did not dilute metals but redistributed contaminants throughout the river. The majority of clean‐up efforts were focused on reducing metal‐rich sediments in the most contaminated upstream reach, implicitly assuming that improvements upstream will positively impact the downstream stations. We tested this assumption by correlating temporal metal trends in sediment between and among stations. The strength of that association (r value) was our indicator of spatial connectivity. Connectivity for both Cu and Cd was strong at small spatial scales. Large‐scale connectivity was strongest with Cu since similar temporal reductions were observed at most monitoring stations. The most upstream station, closest to remediation, had the lowest connectivity, but the next three downstream sites were strongly correlated to trends downstream. Targeted remediation in this reach would be an effective approach to positively influencing the downstream stations.
Sugar maple growth in relation to nutrition and stress in the northeastern United States
Authors: Long Robert P. , Horsley Stephen B. , Hallett Richard A. , Bailey Scott W.
Published: August 2009

Sugar maple, Acer saccharum, decline disease is incited by multiple disturbance factors when imbalanced calcium (Ca), magnesium (Mg), and manganese (Mn) act as predisposing stressors. Our objective in this study was to determine whether factors affecting sugar maple health also affect growth as estimated by basal area increment (BAI). We used 76 northern hardwood stands in northern Pennsylvania, New York, Vermont, and New Hampshire, USA, and found that sugar maple growth was positively related to foliar concentrations of Ca and Mg and stand level estimates of sugar maple crown health during a high stress period from 1987 to 1996. Foliar nutrient threshold values for Ca, Mg, and Mn were used to analyze long‐term BAI trends from 1937 to 1996. Significant (P ≤ 0.05) nutrient threshold‐by‐time interactions indicate changing growth in relation to nutrition during this period. Healthy sugar maples sampled in the 1990s had decreased growth in the 1970s, 10–20 years in advance of the 1980s and 1990s decline episode in Pennsylvania. Even apparently healthy stands that had no defoliation, but had below‐threshold amounts of Ca or Mg and above‐threshold Mn (from foliage samples taken in the mid 1990s), had decreasing growth by the 1970s. Co‐occurring black cherry, Prunus serotina, in a subset of the Pennsylvania and New York stands, showed opposite growth responses with greater growth in stands with below‐threshold Ca and Mg compared with above‐threshold stands. Sugar maple growing on sites with the highest concentrations of foliar Ca and Mg show a general increase in growth from 1937 to 1996 while other stands with lower Ca and Mg concentrations show a stable or decreasing growth trend. We conclude that acid deposition induced changes in soil nutrient status that crossed a threshold necessary to sustain sugar maple growth during the 1970s on some sites. While nutrition of these elements has not been considered in forest management decisions, our research shows species specific responses to Ca and Mg that may reduce health and growth of sugar maple or change species composition, if not addressed.
Dynamics of aboveground carbon stocks in a selectively logged tropical forest
Authors: Blanc Lilian , Echard Marion , Herault Bruno , Bonal Damien , Marcon Eric , Chave Jérôme , Baraloto Christopher
Published: August 2009

The expansion of selective logging in tropical forests may be an important source of global carbon emissions. However, the effects of logging practices on the carbon cycle have never been quantified over long periods of time. We followed the fate of more than 60 000 tropical trees over 23 years to assess changes in aboveground carbon stocks in 48 1.56‐ha plots in French Guiana that represent a gradient of timber harvest intensities, with and without intensive timber stand improvement (TSI) treatments to stimulate timber tree growth. Conventional selective logging led to emissions equivalent to more than a third of aboveground carbon stocks in plots without TSI (85 Mg C/ha), while plots with TSI lost more than one‐half of aboveground carbon stocks (142 Mg C/ha). Within 20 years of logging, plots without TSI sequestered aboveground carbon equivalent to more than 80% of aboveground carbon lost to logging (−70.7 Mg C/ha), and our simulations predicted an equilibrium aboveground carbon balance within 45 years of logging. In contrast, plots with intensive TSI are predicted to require more than 100 years to sequester aboveground carbon lost to emissions. These results indicate that in some tropical forests aboveground carbon storage can be recovered within half a century after conventional logging at moderate harvest intensities.
Influence of human development and predators on nest survival of tundra birds, Arctic Coastal Plain, Alaska
Authors: Liebezeit J. R. , Kendall S. J. , Brown S. , Johnson C. B. , Martin P. , McDonald T. L. , Payer D. C. , Rea C. L. , Streever B. , Wildman A. M. , Zack S.
Published: August 2009

Nest predation may influence population dynamics of birds on the Arctic Coastal Plain (ACP) of Alaska, USA. Anthropogenic development on the ACP is increasing, which may attract nest predators by providing artificial sources of food, perches, den sites, and nest sites. Enhanced populations or concentrations of human‐subsidized predators may reduce nest survival for tundra‐nesting birds. In this study, we tested the hypothesis that nest survival decreases in proximity to human infrastructure. We monitored 1257 nests of 13 shorebird species and 619 nests of four passerine species at seven sites on the ACP from 2002 to 2005. Study sites were chosen to represent a range of distances to infrastructure from 100 m to 80 km. We used Cox proportional hazards regression models to evaluate the effects of background (i.e., natural) factors and infrastructure on nest survival. We documented high spatial and temporal variability in nest survival, and site and year were both included in the best background model. We did not detect an effect of human infrastructure on nest survival for shorebirds as a group. In contrast, we found evidence that risk of predation for passerine nests increased within 5 km of infrastructure. This finding provides quantitative evidence of a relationship between infrastructure and nest survival for breeding passerines on the ACP. A posteriori finer‐scale analyses (within oil field sites and individual species) suggested that Red and Red‐necked Phalaropes combined (Phalaropus fulicarius,P. lobatus) had lower productivity closer to infrastructure and in areas with higher abundance of subsidized predators. However, we did not detect such a relationship between infrastructure and nest survival for Semipalmated and Pectoral Sandpipers (Calidris pusilla,C. melanotos), the two most abundant shorebirds. High variability in environmental conditions, nest survival, and predator numbers between sites and years may have contributed to these inconsistent results. We recommend targeted management actions to minimize anthropogenic effects and suggest new research needed on this issue as expanding development is planned for the ACP of Alaska. In particular, we recommend research on demography of key predators and their importance with respect to nest survival, and experimental studies that better address challenges posed by high natural variability.
Hawaiian native forest conserves water relative to timber plantation: Species and stand traits influence water use
Authors: Kagawa Aurora , Sack Lawren , Duarte Ka‘eo , James Shelley
Published: August 2009

Tropical forests are becoming increasingly alien‐dominated through the establishment of timber plantations and secondary forests. Despite widespread recognition that afforestation results in increased evapotranspiration and lower catchment yields, little is known of the impacts of timber plantations on water balance relative to native forest. Native forest trees have been claimed to use water conservatively and enhance groundwater recharge relative to faster‐growing alien species, and this argument should motivate native forest preservation and restoration. However, data have been available primarily for leaf‐level gas exchange rather than for whole‐plant and stand levels. We measured sap flow of dominant tree and tree fern species over eight weeks in native Metrosideros polymorpha forest and adjacent alien timber plantations on the island of Hawai‘i and estimated total stand transpiration. Metrosideros polymorpha had the lowest values of sap flux density and whole‐tree water use (200 kg·m−2 sapwood·d−1, or 8 kg/d for trees of 35 cm mean diameter at breast height, D), substantially less than timber species Eucalyptus saligna or Fraxinus uhdei (33 and 34 kg/d for trees of 73 and 30 cm mean D, respectively). At the stand level, E. saligna and F. uhdei trees had three‐ and ninefold higher water use, respectively, than native M. polymorpha trees. Understory Cibotium tree ferns were most abundant in M. polymorpha‐dominated forest where they accounted for 70% of water use. Overall, F. uhdei plantation had the highest water use at 1.8 mm/d, more than twice that of either E. saligna plantation or M. polymorpha forest. Forest water use was influenced by species composition, stem density, tree size, sapwood allocation, and understory contributions. Transpiration varied strongly among forest types even within the same wet tropical climate, and in this case, native forest had strikingly conservative water use. Comparisons of vegetation cover in water use should provide additional resolution to ecosystem valuation and land management decisions.
Interaction of historical and nonhistorical disturbances maintains native plant communities
Authors: Davies K. W. , Svejcar T. J. , Bates J. D.
Published: August 2009

Historical disturbance regimes are often considered a critical element in maintaining native plant communities. However, the response of plant communities to disturbance may be fundamentally altered as a consequence of invasive plants, climate change, or prior disturbances. The appropriateness of historical disturbance patterns under modern conditions and the interactions among disturbances are issues that ecologists must address to protect and restore native plant communities. We evaluated the response of Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh plant communities to their historical disturbance regime compared to other disturbance regimes. The historical disturbance regime of these plant communities was periodic fires with minimal grazing by large herbivores. We also investigated the influence of prior disturbance (grazing) on the response of these communities to subsequent disturbance (burning). Treatments were: (1) ungrazed (livestock grazing excluded since 1936) and unburned, (2) grazed and unburned, (3) ungrazed and burned (burned in 1993), and (4) grazed and burned. The ungrazed–burned treatment emulated the historical disturbance regime. Vegetation cover, density, and biomass production were measured the 12th, 13th, and 14th year post‐burning. Prior to burning the presence of Bromus tectorum L., an exotic annual grass, was minimal (<0.5% cover), and vegetation characteristics were similar between grazed and ungrazed treatments. However, litter accumulation was almost twofold greater in ungrazed than in grazed treatments. Long‐term grazing exclusion followed by burning resulted in a substantial B. tectorum invasion, but burning the grazed areas did not produce an invasion. The ungrazed–burned treatment also had less perennial vegetation than other treatments. The accumulation of litter (fuel) in ungrazed treatments may have resulted in greater fire‐induced mortality of perennial vegetation in ungrazed compared to grazed treatments. Our results demonstrate that prior disturbances exert a strong influence on the response of plant communities to subsequent disturbances and suggest that low‐severity disturbances may be needed in some plant communities to increase their resilience to more severe disturbances. Modern deviations from historical conditions can alter ecosystem response to disturbances, thus restoring the historical disturbance regime may not be an appropriate strategy for all ecosystems.
Probabilistic risk-assessment model for birds exposed to granular pesticides
Authors: Moore Dwayne RJ , Fischer David L , Teed R Scott , Rodney Sara I
Published: August 2009

For granular formulations of pesticides, direct consumption by birds is generally the most important route of exposure. A probabilistic exposure model was developed that estimates how many pesticide granules a bird ingests and, from that, the quantity of pesticide ingested. This model, referred to as the “granular pesticide avian risk assessment model” (GranPARAM), has input variables not included in current screening-level assessments for granular pesticides, such as proportion of time for which birds forage in the field, grit ingestion rates, attractiveness of pesticide granules compared with natural grit, and proportions of soil particles and pesticide granules in the size range consumed by birds. For input variables that are uncertain, variable, or both, distributions are used rather than point estimates. Monte Carlo analysis is then performed to propagate input variable uncertainties through the exposure model for granular pesticides. The outputs from the exposure portion of GranPARAM are estimated pesticide doses for each of 20 birds of a selected species on each of 1000 fields. The dose for each bird is compared with a randomly chosen dose from the dose–response curve for that species or an appropriate surrogate. If the exposure dose for a bird exceeds the randomly chosen effects dose, the bird is considered dead; otherwise, the bird is assumed to be alive. Thus, the risk output from GranPARAM is a bar chart showing the percentages of fields with 0/20 dead birds, 1/20 dead birds, 2/20 dead birds, and so forth. Integr Environ Assess Manag 2010;6:260–272. © 2009 SETAC
Development of a preliminary relative risk model for evaluating regional ecological conditions in the Delaware River Estuary, USA
Authors: Iannuzzi Timothy J , Durda Judi L , Preziosi Damian V , Ludwig David F , Stahl Ralph G , DeSantis Amanda A , Hoke Robert A
Published: August 2009

Effective environmental management and restoration of urbanized systems such as the Delaware River Estuary requires a holistic understanding of the relative importance of various stressor-related impacts throughout the watershed, both historical and ongoing. To that end, it is important to involve as many stakeholders as possible in the management process and to develop a system for sharing of scientific data and information, as well as effective technical tools for evaluating and disseminating the data needed to make management decisions. In this study, we describe a preliminary assessment that was undertaken to evaluate the relative risks for the variety of stressors currently operating within the Delaware Estuary using a relative risk model (RRM) framework. This model was constructed using existing data and information on the ecological conditions and stressors in the main-stem Delaware River below the head of tide at Trenton, New Jersey, USA. A large database was developed with pertinent data from a variety of library, scientific, and regulatory sources. Data were compiled, reviewed, and characterized before development of the Estuary-specific RRM. Our primary goals and objectives in developing this preliminary RRM for the Estuary were to 1) determine if the RRM framework can be adapted to a large complex estuarine system such as the Delaware River, 2) identify the issues associated with adapting the model framework to the various management issues and regional areas/habitats of the River, 3) help identify data needs and potential refinements that might be needed to more specifically quantify relative stressor risks in various areas and habitats of the Estuary to better inform future management goals/actions by Stakeholders. The key conclusions of our preliminary assessment are 1) a diverse suite of stressors is likely affecting the ecological conditions of the Delaware Estuary, 2) chemical (toxicants/contaminants) and physical (sedimentation, habitat loss) stressors were found to be on par with regards to their ranking, and 3) the RRM, in its current form, made it difficult to effectively balance the inequality in the sizes of the study subareas considered in the assessment. Management objectives and related research activities should focus on collecting the necessary data and information to further refine the RRM and assess the relative impacts of these stressors at various scales in the Estuary. By having such a framework and tool available, we believe that stakeholders within the Delaware River watershed will be able to make more informed and risk-based management decisions regarding restoration options for the Estuary. Integr Environ Assess Manag 2010; 6:164–179. © 2009 SETAC
General recommendations for soil ecotoxicological tests suitable for the environmental risk assessment of genetically modified plants
Authors: Römbke Jörg , Jänsch Stephan , Meier Matthias , Hilbeck Angelika , Teichmann Hanka , Tappeser Beatrix
Published: August 2009

Before a genetically modified plant (GMP) can be placed on the market in the European Union (EU), an environmental risk assessment has to be conducted according to EU-Directive 2001/18/EC or Regulation (EC) No. 1829/2003 of the European Parliament and of the Council. However, no harmonized concept for ecotoxicological testing is available today that considers the characteristics of GMPs as a whole. In fact, to date, mainly ecotoxicological tests originally developed and standardized for pesticides are used for this purpose. Frequently in these tests, not the whole GMP is tested but only specific transgene products (mainly toxins). In this contribution, ecotoxicological methods developed for the testing of pesticides are evaluated for whether they are suitable for risk assessment of GMPs as well. In total, 105 test methods covering a wide range of terrestrial invertebrates, microbes, and plants (laboratory, semifield, and field levels) were assessed. Only 7 of them had already been used with GMPs, and in about 20 studies the existing tests methods were modified, mostly in a way such that nonstandard species were used. In the laboratory, few earthworm and nontarget arthropod (NTA) species as well as collembolans and isopods were tested, and, in the field, only the litter-bag test was used. Clearly, more species than these few standard organisms currently in use have to be selected for testing purposes. A more detailed analysis of GMP tests with soil invertebrates published in the literature revealed that some of the relevant GMP exposure routes, such as via bulk soil, soil porewater, and litter from GMPs, are well covered. However, studies addressing either consumption of GMPs themselves or secondary exposure after GMPs have been taken up by invertebrates that feed on living or dead GMPs are underrepresented. Integr Environ Assess Manag 2010;6:287–300. © 2009 SETAC
Darcy-Stokes Streamline Simulation for the Tahe-Fractured Reservoir With Cavities
Authors: Peng Xiaolong , Du Zhimin , Liang Baosheng , Qi Zhilin
Published: August 2009

The Tahe-fractured reservoir has very special cavities and fractures. There is no flow in the rock matrix; and cavities provide the main storage space and even have the scale of meters. Consequently, the reservoir cannot be considered as a traditional continuous porous medium. Instead of a dual-porosity flow model, a Darcy-Stokes compound single-porosity model is developed with the whole flow area divided into a Darcy-flow region, which obeys Darcy's Law, and a free-flow region, which satisfies a Navier-Stokes flow.

Through a Tahe real reservoir case, it is found that a cavity-fracture dual-porosity model is unable to reflect the rapid bottom-water breakthrough, and that finite difference method has a hard time getting convergence in the strong heterogeneous reservoir. On the other hand, streamline simulation with a Darcy-Stokes model developed in this paper successfully demonstrates flow behavior of bottom- and edge-water flowing into the wellbore through the cavity: water advances fast, water breakthrough happens in a short time, and water cut rises rapidly.

In application, a streamline numerical model for Darcy-Stokes flow is built by combining two-phase Navier-Stokes streamline modeling and streamline-based simulation of Darcy flow. Examples show that both a Darcy-Stokes model and conventional Darcy model give the similar simulation results of saturation and pressure distributions in the Darcy-flow region. However, fluid flow behaviors from these two models differ in the free-flow region. Such a difference lies in the different treatment of velocities: Our Darcy-Stokes model considers the fluid velocity difference caused by a shear stress effect; and the Darcy model only uses the average velocity of the fluid in the cavity, which means the fluid almost moves at the same speed in the free-flow zone and does not agree with the reality.
Use of Bayesian Methods to Model Soil Aggregation in Undisturbed Semiarid Grasslands
Authors: Wick Abbey F. , Huzurbazar Snehalata V. , Stahl Peter D.
Published: August 2009

Comparisons of soil aggregation and aggregate‐protected organic matter among soil textures in the same climatic zone and of the same mineralogical composition are somewhat limited. Two undisturbed, semiarid sites in northeastern Wyoming were selected to determine the differences in aggregation and organic matter between loam and sandy clay loam soils. Additionally, data from these two sites were used to illustrate differences between two statistical approaches to data analysis: Bayesian modeling in the context of a two‐sample comparison of means and conventionalt‐tests. Examination of posterior distributions (Bayesian modeling) and confidence intervals (conventionalt‐tests) resulted in similar conclusions about the influence of soil texture on aggregation and C and N concentrations. Loam soils generally had more structure (as indicated by higher macroaggregation) and aggregate‐protected C and N than sandy clay loam soils, which had greater amounts of available C and N not protected by aggregates. For soils in undisturbed semiarid grasslands with similar clay contents, in the range of 11 to 24%, we suspect that aggregate stability was primarily affected by sand content, while aggregate C and N accumulations were influenced by silt. A higher percentage of silt in the loam soils appeared to have provided enough of a difference in small pore space between the two soil types to result in higher C and N storage in loam soils relative to sandy clay loam soils. Soil texture is a major driving force behind aggregation as well as C and N storage in semiarid soils of the same mineralogy.
Spatial Relationships of Phosphorus Sorption in a Seasonally Saturated Constructed Wetland Soil
Authors: Maynard Jonathan J. , O'Geen Anthony T. , Dahlgren Randy A.
Published: August 2009

Constructed wetlands can be important sinks of P in agricultural landscapes; however, the long‐term ability of these systems to retain P often diminishes with time. This study used a spatially explicit statistical approach to characterize spatial patterns of soil properties and their correlation with P sorption in an 11‐yr‐old, seasonally saturated, constructed wetland receiving runoff from irrigated agriculture. The results were used to link the spatial pattern of P sorption with hydrologic, biogeochemical, and pedologic processes. A spatial sampling design was used and soil samples were measured for total P, bioavailable P, P sorption index (PSI), total C and N, texture, oxalate‐ and dithionite‐extractable Fe and Mn, pH, electrical conductivity, water‐extractable Mg, Ca, and Na, and sedimentation rate. Wetland hydrodynamics was a primary factor shaping the spatial distribution of wetland soil properties, creating three distinct hydrologic and biogeochemical zones (e.g., sediment deposition, transition, and Fe oxide transformation). Soil properties with the strongest correlation to the PSI included oxalate‐extractable Fe, clay, total C, and silt. In the sediment‐deposition zone, sedimentation was the dominant process influencing P sorption, contributing fresh sediments with reactive surfaces for P sorption. In contrast, the Fe oxide transformation zone received little sedimentation, resulting in greater exposure time for surface sediment alteration. Increased exposure resulted in dissolution of crystalline Fe oxides and reformation of poorly crystalline Fe oxides in a thin oxidative lens at the sediment–water column interface, thus increasing P sorption capacity. This spatially explicit investigation of P sorption in seasonally saturated wetland soils provided a robust framework within which to evaluate the wetland soil processes controlling P sorption capacity and the efficacy for long‐term sorption potential.
Sensitivity of Ground‐Based Remote Sensing Estimates of Wheat Chlorophyll Content to Variation in Soil Reflectance
Authors: Eitel J. U. H. , Long D. S. , Gessler P. E. , Hunt E. R. , Brown D. J.
Published: August 2009

Spectral indices (SI) derived from crop reflectance data are sensitive to chlorophyll a and b content (Chl). However, the SI–Chl relationship might be confounded by variation in leaf area index (LAI) and soil background reflectance, especially in semiarid environments where water determines crop growth. This study evaluated the sensitivity of SI to variation in soil reflectance and how this may affect overall SI performance for ground‐based sensing of Chl in dryland wheat (Triticum aestivum L.). Selected SI were computed from spectra simulated by the PROSPECT‐SAIL radiative‐transfer model for 5 LAI values, 7 Chl values, and 121 dry soil surface reflectance spectra. These spectra represented soils across major wheat growing areas in the United States. Soil properties and reflectance varied widely among the soils indicated by the high SI variation for LAI values < 1.5. Overall, soil background variation contributed less to the observed SI variability (<6%) than LAI (<97%). Combined indices [i.e., Normalized Difference Red Edge Index (NDRE)/Normalized Difference Vegetation Index (NDVI) and Modified Chlorophyll Absorption Ratio Index (MCARI)/Second Modified Triangular Vegetation Index (MTVI)] were least affected by soil background variation than single indices (i.e., NDVI). Results showed that ground sensing of Chl may be improved by means of combined indices that are resistant to soil background and LAI. Empirical measurements verified that the modeling results were a reliable representation of the influence of Chl, LAI, and soil on canopy reflectance. Further research is needed to evaluate the effect of soil moisture, surface roughness, residue, growth stage, and shadow on SI.
Organoclay‐Based Formulations to Reduce the Environmental Impact of the Herbicide Diuron in Olive Groves
Authors: Trigo C. , Celis R. , Hermosín M. C. , Cornejo J.
Published: August 2009

Ground and surface water contamination caused by undesirable transport losses of herbicides commonly applied to olive (Olea Europaea) groves in Spain and other Mediterranean countries is demanding strategies to reduce the environmental impact of such herbicides. In this work, organoclay‐based formulations of a herbicide widely applied to olive groves, diuron [3‐(3,4‐dichlorophenyl)‐1,1‐dimethyl urea], were prepared by preadsorbing the herbicide on three organoclays. Then, the ability of the organoclay‐based formulations to reduce the herbicide release rate and leaching potential in two soils as compared to a standard commercial formulation of the herbicide was assessed. The organoclays were obtained by treating Wyoming montmorillonite (SWy‐2) and Arizona montmorillonite (SAz‐1) with an amount of spermine (SPERM) or hexadecyltrimethylammonium (HDTMA) cations equal to 100% of the cation exchange capacity of the montmorillonites. Batch release and column leaching tests indicated that the organoclay‐based formulations of diuron made the release of the herbicide slower and reduced its leaching potential in soils, as compared with a standard commercial formulation containing the herbicide in a readily available form. Soil incubation experiments revealed that the persistence of the herbicide applied to soil as organoclay‐based formulations was only slightly prolonged compared with the herbicide applied in a readily available form, and that most herbicide in the formulations was ultimately available for degradation. The use of organoclay‐based formulations is proposed as a strategy to reduce extensive transport losses associated with the application of diuron in high‐risk scenarios, such as Mediterranean olive groves.
Biological Application of Micro‐Electro Mechanical Systems Microelectrode Array Sensors for Direct Measurement of Phosphate in the Enhanced Biological Phosphorous Removal Process
Authors: Lee Woo Hyoung , Lee Jin‐Hwan , Bishop Paul L. , Papautsky Ian
Published: August 2009

The determination of phosphate has been of great importance in the fields of clinical, environmental, and horticultural analysis for over three decades. New cobalt‐based micro‐electro mechanical systems (MEMS) microelectrode array (MEA) sensors for direct measurement of phosphate in small environmental samples, such as microbial aggregates, has been introduced and applied here for in situ measurement of phosphate within activated sludge flocs in the enhanced biological phosphorus removal process. The MEMS technologies offer the advantages of accurate fabrication methods, reduced complexity of the fabrication process, mass production, low cost, and increased reliability. Well‐defined phosphate profiles across the flocs were observed under anaerobic conditions, during which, phosphate was released from the flocs, using the MEMS MEA sensor. The microprofiles were compared with the microprofiles measured using conventional phosphate microelectrodes. The developed MEMS MEA sensors were useful tools for the in situ measurement of phosphate in small aggregates.
Predicting the Degradability of Waste Activated Sludge
Authors: Jones Richard , Parker Wayne , Zhu Henry , Houweling Dwight , Murthy Sudhir
Published: August 2009

The objective of this study was to identify methods for estimating anaerobic digestibility of waste activated sludge (WAS). The WAS streams were generated in three sequencing batch reactors (SBRs) treating municipal wastewater. The wastewater and WAS properties were initially determined through simulation of SBR operation with BioWin (EnviroSim Associates Ltd., Flamborough, Ontario, Canada). Samples of WAS from the SBRs were subsequently characterized through respirometry and batch anaerobic digestion. Respirometry was an effective tool for characterizing the active fraction of WAS and could be a suitable technique for determining sludge composition for input to anaerobic models. Anaerobic digestion of the WAS revealed decreasing methane production and lower chemical oxygen demand removals as the SRT of the sludge increased. BioWin was capable of accurately describing the digestion of the WAS samples for typical digester SRTs. For extended digestion times (i.e., greater than 30 days), some degradation of the endogenous decay products was assumed to achieve accurate simulations for all sludge SRTs.
When the Book is Better than the Movie: How Contrasting Video Cases Influence Text Learning
Authors: Beitzel Brian D. , Derry Sharon J.
Published: August 2009

Video usage in educational contexts is on the rise. We examined 3 alternative theories about cognitive mechanisms of learning and their implications for instructional design when video is employed to enhance text-based learning. Hypothesis-testing procedures followed a falsificationist approach, grounded in philosophy of science literature. Undergraduate students acquired learning-science concepts through web-based activities that involved studying reading material. Participants contrasted video cases before reading in one experimental condition, and after reading in another. Participants in a control condition read the same texts but saw no video cases. Recall results after a 2-day delay favored the instructional design in which video cases were contrasted after reading a text, consistent with a schema-elaboration hypothesis.
Solar Ethics: A New Paradigm for Environmental Ethics and Education?
Authors: Peters Michael A. , Hung Ruyu
Published: August 2009

This article provides grounds for a new paradigm of environmental ethics and education based on the centrality of the sun and solar system – a shift from anthropocentrism to solar systemism. The article provides some grounds for this shift from the physical sciences that considers the planet Earth as part of a wider system that is dependent upon the star at its center. The article reviews the critcisms of anthropocentrism in the literature on environmental ethics and advances a set of cosmological arguments for considering the term ‘environment’ to include ‘beyond Earth’. Solar ethics is a frame that will help to re-position humans within nature and lead to a more sustainable world view.
Think Tanks and the Web: Measuring Visibility and Influence
Authors: McNutt Kathleen , Marchildon Gregory
Published: August 2009

There is a significant body of literature assessing the influence of think tanks; however, there has been relatively little research on the online impact of think tanks’ research activity. Differentiating the popularity of a policy think tank from its policy relevance is an important consideration in evaluating the impact of policy institutes on the Web. This study measures the perceived reliability of information as defined by web-based users. To measure the impact of think tanks’ web-based popularity and policy relevance, think tank participation in five separate policy domains including social policy, equalization, climate change, clean energy, and peacemaking/peace building is studied using hyperlink analysis.
Effect of the Polysaccharide Extract from the Edible Mushroom Pleurotus ostreatus against Infectious Bursal Disease Virus
Authors: Selegean Mircea , Putz Mihai V. , Rugea Tatiana
Published: August 2009

The polysaccharide-containing extracellular fractions (EFs) of the edible mushroom Pleurotus ostreatus have immunomodulating effects. Being aware of these therapeutic effects of mushroom extracts, we have investigated the synergistic relations between these extracts and BIAVAC and BIAROMVAC vaccines. These vaccines target the stimulation of the immune system in commercial poultry, which are extremely vulnerable in the first days of their lives. By administrating EF with polysaccharides from P. ostreatus to unvaccinated broilers we have noticed slow stimulation of maternal antibodies against infectious bursal disease (IBD) starting from four weeks post hatching. For the broilers vaccinated with BIAVAC and BIAROMVAC vaccines a low to almost complete lack of IBD maternal antibodies has been recorded. By adding 5% and 15% EF in the water intake, as compared to the reaction of the immune system in the previous experiment, the level of IBD antibodies was increased. This has led us to believe that by using this combination of BIAVAC and BIAROMVAC vaccine and EF from P. ostreatus we can obtain good results in stimulating the production of IBD antibodies in the period of the chicken first days of life, which are critical to broilers’ survival. This can be rationalized by the newly proposed reactivity biological activity (ReBiAc) principles by examining the parabolic relationship between EF administration and recorded biological activity.
Design, Fabrication, and Properties of High Damping Metal Matrix Composites—A Review
Authors: Lu Hui , Wang Xianping , Zhang Tao , Cheng Zhijun , Fang Qianfeng
Published: August 2009

Nowadays it is commonly considered that high damping materials which have both the good mechanical properties as structural materials and the high damping capacity for vibration damping are the most direct vibration damping solution. In metals and alloys however, exhibiting simultaneously high damping capacity and good mechanical properties has been noted to be normally incompatible because the microscopic mechanisms responsible for internal friction (namely damping capacity) are dependent upon the parameters that control mechanical strength. To achieve a compromise, one of the most important methods is to develop two-phase composites, in which each phase plays a specific role: damping or mechanical strength. In this review, we have summarized the development of the design concept of high damping composite materials and the investigation of their fabrication and properties, including mechanical and damping properties, and suggested a new design concept of high damping composite materials where the hard ceramic additives exhibit high damping capacity at room temperature owing to the stress-induced reorientation of high density point defects in the ceramic phases and the high damping capacity of the composite comes mainly from the ceramic phases.
Production of β-Maltooligosaccharides of α- and δ-Tocopherols by Klebsiella pneumoniae and Cyclodextrin Glucanotransferase as Anti-Allergic Agents
Authors: Shimoda Kei , Akagi Masaaki , Hamada Hiroki
Published: August 2009

The glycosylation of α- and δ-tocopherols using Klebsiella pneumoniae and cyclodextrin glucanotransferase (CGTase) was investigated. K. pneumoniae converted α- and δ-tocopherols into the corresponding β-glucosides in 10 and 8% yield, respectively. CGTase glycosylated α-tocopheryl β-glucoside to α-tocopheryl β-maltoside (51%) and α-tocopheryl β-maltotrioside (35%). On the other hand, δ-tocopheryl β-glucoside was converted into the corresponding β-maltoside (45%) and β-maltotrioside (29%) by CGTase. The β-glucoside of α-tocopherol, and β-glucoside and β-maltoside of δ-tocopherol showed inhibitory effects on IgE antibody production and on histamine release from rat peritoneal mast cells.
Evaluating Principal Components Analysis for Identifying Optimal Bands Using Wetland Hyperspectral Measurements From the Great Lakes, USA
Authors: Torbick Nathan , Becker Brian
Published: August 2009

Mapping species composition is a focus of the wetland science community as this information will substantially enhance assessment and monitoring abilities. Hyperspectral remote sensing has been utilized as a cost-efficient approach. While hyperspectral instruments can record hundreds of contiguous narrow bands, much of the data are redundant and/or provide no increase in utility for distinguishing objects. Knowledge of the optimal bands allows users to efficiently focus on bands that provide the most information and several data reduction tools are available. The objective of this Communication was to evaluate Principal Components Analysis (PCA) for identifying optimal bands to discriminate wetland plant species. In-situ hyperspectral reflectance measurements were obtained for thirty-five species in two diverse Great Lakes wetlands. PCA was executed on a suite of categories based on botanical plant/substrate characteristics and spectral configuration schemes. Results showed that the data dependency of PCA makes it a poor, stand alone tool for selecting optimal wavelengths. PCA does not allow diagnostic comparison across sites and wavelengths identified by PCA do not necessarily represent wavelengths that indicate biophysical attributes of interest. Further, narrow bands captured by hyperspectral sensors need to be substantially re-sampled and/or smoothed in order for PCA to identify useful information.
Estimation of Mexico’s Informal Economy and Remittances Using Nighttime Imagery
Authors: Ghosh Tilottama , Anderson Sharolyn , Powell Rebecca , Sutton Paul , Elvidge Christopher
Published: August 2009

Accurate estimates of the magnitude and spatial distribution of both formal and informal economic activity have many useful applications. Developing alternative methods for making estimates of these economic activities may prove to be useful when other measures are of suspect accuracy or unavailable. This research explores the potential for estimating the formal and informal economy for Mexico using known relationships between the spatial patterns of nighttime satellite imagery and economic activity in the United States (U.S.). Regression models have been developed between spatial patterns of nighttime imagery and Adjusted Official Gross State Product (AGSP) for the U.S. states. These regression parameters derived from the regression models of the U.S. were ‘blindly’ applied to Mexico to estimate the Estimated Gross State Income (EGSI) at the sub-national level and the Estimated Gross Domestic Income (EGDI) at the national level. Comparison of the EGDI estimate of Mexico against the official Gross National Income (GNI) estimate suggests that the magnitude of Mexico’s informal economy and the inflow of remittances are 150 percent larger than their existing official estimates in the GNI.
Integrated Methodology for Estimating Water Use in Mediterranean Agricultural Areas
Authors: Alexandridis Thomas K. , Cherif Ines , Chemin Yann , Silleos George N. , Stavrinos Eleftherios , Zalidis George C.
Published: August 2009

Agricultural use is by far the largest consumer of fresh water worldwide, especially in the Mediterranean, where it has reached unsustainable levels, thus posing a serious threat to water resources. Having a good estimate of the water used in an agricultural area would help water managers create incentives for water savings at the farmer and basin level, and meet the demands of the European Water Framework Directive. This work presents an integrated methodology for estimating water use in Mediterranean agricultural areas. It is based on well established methods of estimating the actual evapotranspiration through surface energy fluxes, customized for better performance under the Mediterranean conditions: small parcel sizes, detailed crop pattern, and lack of necessary data. The methodology has been tested and validated on the agricultural plain of the river Strimonas (Greece) using a time series of Terra MODIS and Landsat 5 TM satellite images, and used to produce a seasonal water use map at a high spatial resolution. Finally, a tool has been designed to implement the methodology with a user-friendly interface, in order to facilitate its operational use.
A Self-Referencing Intensity Based Polymer Optical Fiber Sensor for Liquid Detection
Authors: Montero David  Sánchez , Vázquez Carmen , Möllers Ingo , Arrúe Jon , Jäger Dieter
Published: August 2009

A novel self-referencing fiber optic intensity sensor based on bending losses of a partially polished polymer optical fiber (POF) coupler is presented. The coupling ratio (K) depends on the external liquid in which the sensor is immersed. It is possible to distinguish between different liquids and to detect their presence. Experimental results for the most usual liquids found in industry, like water and oil, are given. K value increases up to 10% from the nominal value depending on the liquid. Sensor temperature dependence has also been studied for a range from 25 ºC (environmental condition) to 50 ºC. Any sector requiring liquid level measurements in flammable atmospheres can benefit from this intrinsically safe technology.
A Novel Design of Grooved Fibers for Fiber-Optic Localized Plasmon Resonance Biosensors
Authors: Huang Ching-Te , Jen Chun-Ping , Chao Tzu-Chien , Wu Wei-Te , Li Wan-Yun , Chau Lai-Kwan
Published: August 2009

Bio-molecular recognition is detected by the unique optical properties of self-assembled gold nanoparticles on the unclad portions of an optical fiber whose surfaces have been modified with a receptor. To enhance the performance of the sensing platform, the sensing element is integrated with a microfluidic chip to reduce sample and reagent volume, to shorten response time and analysis time, as well as to increase sensitivity. The main purpose of the present study is to design grooves on the optical fiber for the FO-LPR microfluidic chip and investigate the effect of the groove geometry on the biochemical binding kinetics through simulations. The optical fiber is designed and termed as U-type or D-type based on the shape of the grooves. The numerical results indicate that the design of the D-type fiber exhibits efficient performance on biochemical binding. The grooves designed on the optical fiber also induce chaotic advection to enhance the mixing in the microchannel. The mixing patterns indicate that D-type grooves enhance the mixing more effectively than U-type grooves. D-type fiber with six grooves is the optimum design according to the numerical results. The experimental results show that the D-type fiber could sustain larger elongation than the U-type fiber. Furthermore, this study successfully demonstrates the feasibility of fabricating the grooved optical fibers by the femtosecond laser, and making a transmission-based FO-LPR probe for chemical sensing. The sensor resolution of the sensor implementing the D-type fiber modified by gold nanoparticles was 4.1 × 10-7 RIU, which is much more sensitive than that of U-type optical fiber (1.8 × 10-3 RIU).
Exploiting Surface Plasmon Resonance (SPR) Technology for the Identification of Fibroblast Growth Factor-2 (FGF2) Antagonists Endowed with Antiangiogenic Activity
Authors: Rusnati Marco , Bugatti Antonella , Mitola Stefania , Leali Daria , Bergese Paolo , Depero Laura E. , Presta Marco
Published: August 2009

Angiogenesis, the process of new blood vessel formation, is implicated in various physiological/pathological conditions, including embryonic development, inflammation and tumor growth. Fibroblast growth factor-2 (FGF2) is a heparin-binding angiogenic growth factor involved in various physiopathological processes, including tumor neovascularization. Accordingly, FGF2 is considered a target for antiangiogenic therapies. Thus, numerous natural/synthetic compounds have been tested for their capacity to bind and sequester FGF2 in the extracellular environment preventing its interaction with cellular receptors. We have exploited surface plasmon resonance (SPR) technique in search for antiangiogenic FGF2 binders/antagonists. In this review we will summarize our experience in SPR-based angiogenesis research, with the aim to validate SPR as a first line screening for the identification of antiangiogenic compounds.