bluuebunny/crossref_metadata_2025 huggingface dataset:
Microscale Patterning of Single Crystal Diamond Using Sidero-Metal/Diamond Thermochemical Reaction
Authors: Morofushi Yuko , Matsushita Hajime , Miki Norihisa
Published: March 2010

In this paper we propose and demonstrate micro patterning processes of single crystal diamond using thermochemical reaction of diamond with a sidero-metal and elucidate the reaction involved. Single crystal diamond processes a variety of excellent characteristics, such as hardness and wear resistance, and hence, is expected to be a new material for not only micro machining tools but also innovative micro devices. It is mandatory to develop a patterning process of diamond with high precision and at low cost. Laser processing is currently widely used, but it is a serial process and costly. Film deposition and plasma etching are other effective methods while they are time consuming. Thermochemical reaction between diamond and sidero-metals is well known in the field of mechanical machining. Diamond tools cannot machine sidero-metals, such as iron, nickel, and cobalt, when the diamond tools wear instead of the sidero-metals. We used this reaction to micro pattern single crystal diamond. We used nickel as the sidero-metal that was patterned either directly on a bulk of single crystal diamond or on a silicon substrate. We term the former and the latter processes as direct and indirect patterning processes, respectively. In the indirect patterning a bulk of single crystal diamond was placed on the substrate. The pattern was negatively transferred to the diamond after thermal treatment in the air at ˜1000K in both processes. The sidero-metal layer can be patterned by photolithography, which enables precise manufacturing and mass production. The direct and indirect patterning achieved etching rates of ˜0.5μm/min and ˜0.2μm/min, respectively, both of which increased as the annealing temperature increased while the indirect patterning did not require micro patterning of photoresist on a bulk diamond several millimeters squire and involved much less difficult processes than the direct patterning. The thermochemical reaction is reported to be caused by; diffusion of carbon from diamond into the sidero-metal, oxidation-reduction reaction between diamond and the metal, oxidation of diamond, and carbide formation. Carbide formation was not observed when we used nickel as the sidero-metal. When the direct and indirect patterning was conducted in nitrogen, the pattern transfer was observed but the etching rate was extremely low. Therefore, oxidation-reduction reaction is dominant in the direct patterning. In the indirect patterning, the etching continued even after the nickel and diamond was not in contact. The thickness of removed diamond was by far greater than the thickness of the nickel layer. Hence, we consider that diamond was etched by oxide-reduction reaction between the diamond and the metal while they were in contact at the beginning and then, the oxidation of diamond became dominant in the indirect patterning. The process proposed herein is readily applicable to manufacture micro devices that exploit excellent characteristics of single crystal diamond.
The Heterogeneous Multiscale Method for Dynamics of Solids with Applications to Brittle Cracks
Authors: Yang Jerry , Li Xiantao
Published: March 2010

We present a multiscale method for the modeling of dynamics of crystalline solids. The method employs the continuum elastodynamics model to introduce loading conditions and capture elastic waves, and near isolated defects, molecular dynamics (MD) model is used to resolve the local structure at the atomic scale. The coupling of the two models is achieved based on the framework of the heterogeneous multiscale method (HMM) and a consistent coupling condition with special treatment of the MD boundary condition. Application to the dynamics of a brittle crack under various loading conditions is presented. Elastic waves are observed to pass through the interface from atomistic region to the continuum region and reversely. Thresholds of strength and duration of shock waves to launch the crack opening are quantitatively studied and related to the inertia effect of crack tips.
Direct Approach to Atomistic Ab Initio Studies of Precipitate Growth in Alloys
Authors: Ehlers Flemming JH , Holmestad Randi
Published: March 2010

A dramatic gain in the knowledge of precipitate formation, composition, and evolution in alloys has been achieved in the recent years with improvement of transmission electron microscopy techniques for direct structural imaging [1]. A detailed understanding of the microstructure is often essential for control and manipulation of materials properties: an important example for metals is the significant hardening of Al alloys by particular precipitates from a sequence strongly dependent on alloying element concentration and the treatment of the material [2].
The wealth of experimental information provides a playground for theory in the context of elucidating precipitate growth mechanisms and influence on the host material. A head-on approach to atomistic modelling of these phenomena using an ab initio based scheme is conventionally deemed highly desired but impractical. The basic argument is that the system of any reasonably sized (i.e. realistic) and well isolated microstructure will simply contain too many atoms.
We will challenge this conventional view: it is argued that most of the atoms of the above mentioned system do not play an active role in the growth discussion, hence need not be included in the modelling. Subsequently, a model system is presented which offers a highly accurate description of the interface between the host lattice and a microstructure of an arbitrary size, for the case where this interface is coherent and compositionally abrupt. When used in conjunction with other approaches already available, this model system offers a direct approach to atomistic ab initio studies of microstructure growth.
A general introduction to the modelling scheme will be presented, with the particular application being the main hardening precipitate β'' in the Al-Mg-Si alloy.
[1] K. W. Urban, Nature Mater. 8, 260 (2009).
[2] C. D. Marioara, S. J. Andersen, H. W. Zandbergen, and R. Holmestad, Metal. Mater. Trans. A 36A, 691 (2005).
Selective Biofunctionalization all-(111) Surface Silicon Nanowires
Authors: Masood Muhammad , Chen Songuye , Carlen Edwin T , Berg Albert Van den
Published: March 2010

Selective biomolecular functionalization of our all-(111) surface silicon nanowire (SiNW) biosensors using covalently linked alkyl- monolayers is demonstrated. Monolayers were made using a commercially available six member carbon precursor N-(5-Hexynyl) phthalimide and UV based hydrosylilation reaction. Contact angle and x-ray photoelectron spectroscopy (XPS) measurements were used to characterize the monolayer at different stages on planar Si (111) samples. Terminal amine groups on the monolayer surface were used for further conjugation with (+)-Biotin N-hydroxysuccinimide ester after deprotection of the phthalimide group with a methylamine solution. Selective biofunctionalization was demonstrated by reacting the SiNW-monolayer-biotin surface with 5 nm gold nanoparticles conjugated with streptavidin and subsequent high resolution scanning electron microscopy imaging.
Human heterochromatin protein 1 isoform HP1β enhances androgen receptor activity and is implicated in prostate cancer growth
Authors: Shiota M , Song Y , Yokomizo A , Tada Y , Kuroiwa K , Eto M , Oda Y , Inokuchi J , Uchiumi T , Fujimoto N , Seki N , Naito S
Published: March 2010

There are currently few successful therapies for castration-resistant prostate cancer (CRPC). CRPC is thought to result from augmented activation of the androgen/androgen receptor (AR) signaling pathway, which could be enhanced by AR cofactors. In this study, heterochromatin protein 1β (HP1β), but not HP1α or HP1γ was found to be an AR cofactor. HP1β interacted with the AR, and enhanced the DNA-binding ability of AR to androgen-responsive element in the prostate-specific antigen enhancer and promoter regions, and to increase the transcription of AR target genes. In prostate cancer (PCa) tissues, HP1β expressions correlated with Gleason score and tri-methylation levels of histone H3 lysine 9. Silencing of HP1β suppressed the growth of AR-expressing PCa cells by inducing cell-cycle arrest at the G1 phase, similar to inhibition of androgen/AR signaling. Furthermore, HP1β was overexpressed in castration-resistant LNCaP derivative CxR cells, and HP1β knockdown also suppressed the cell growth in CxR cells. These findings indicate that HP1β is involved in the proliferation of AR-expressing PCa cells and progression to CRPC as an AR coactivator. Modulation of HP1β expression or function might be a useful strategy for developing novel therapeutics for PCa, even in CRPC.
Dealing with uncertainty in ecosystem models: lessons from a complex salmon model
Authors: McElhany Paul , Steel E. Ashley , Avery Karen , Yoder Naomi , Busack Craig , Thompson Brad
Published: March 2010

Ecosystem models have been developed for assessment and management in a wide variety of environments. As model complexity increases, it becomes more difficult to trace how imperfect knowledge of internal model parameters, data inputs, or relationships among parameters might impact model results, affecting predictions and subsequent management decisions. Sensitivity analysis is an essential component of model evaluation, particularly when models are used to make management decisions. Results should be expressed as probabilities and should realistically account for uncertainty. When models are particularly complex, this can be difficult to do and to present in ways that do not obfuscate essential results. We conducted a sensitivity analysis of the Ecosystem Diagnosis and Treatment (EDT) model, which predicts salmon productivity and capacity as a function of ecosystem conditions. We used a novel “structured sensitivity analysis” approach that is particularly useful for very complex models or those with an abundance of interconnected parameters. We identified small, medium, and large plausible ranges for both input data and model parameters. Using a Monte Carlo approach, we explored the variation in output, prediction intervals, and sensitivity indices, given these plausible input distributions. The analyses indicated that, as a consequence of internal parameter uncertainty, EDT productivity and capacity predictions lack the precision needed for many management applications. However, EDT prioritization of reaches for preservation or restoration was more robust to given input uncertainties, indicating that EDT may be more useful as a relative measure of fish performance than as an absolute measure. Like all large models, if EDT output is to be used as input to other models or management tools it is important to explicitly incorporate the uncertainty and sensitivity analyses into such secondary analyses. Sensitivity analyses should become standard operating procedure for evaluation of ecosystem models.
Responses to alternative rainfall regimes and antipoaching in a migratory system
Authors: Holdo Ricardo M. , Galvin Kathleen A. , Knapp Eli , Polasky Stephen , Hilborn Ray , Holt Robert D.
Published: March 2010

Migratory ungulates may be particularly vulnerable to the challenges imposed by growing human populations and climate change. These species depend on vast areas to sustain their migratory behavior, and in many cases come into frequent contact with human populations outside protected areas. They may also act as spatial coupling agents allowing feedbacks between ecological systems and local economies, particularly in the agropastoral subsistence economies found in the African savanna biome. We used HUMENTS, a spatially realistic socioecological model of the Greater Serengeti Ecosystem in East Africa, to explore the potential impacts of changing climate and poaching on the migratory wildebeest (Connochaetes taurinus) population, the fire regime, and habitat structure in the ecosystem, as well as changes in the size and economic activities of the human population outside the protected area. Unlike earlier models, the HUMENTS model predicted only moderate declines in the wildebeest population associated with an increasing human population over the next century, with a gradual expansion of agriculture, more poaching, and increases in fire frequency and reduced tree density. Changes in rainfall were predicted to have strong asymmetric effects on the size and economic activity of the human population and on livestock, and more moderate effects on wildlife and other ecological indicators. Conversely, antipoaching had a stronger effect on the ecological portion of the system because of its effect on wildebeest (and therefore on fire and habitat structure), and a weaker effect on the socioeconomic component, except in areas directly adjacent to the protected‐area boundary, which were affected by crop‐raiding and the availability of wildlife as a source of income. The results highlight the strong direct and indirect effects of rainfall on the various components of socioecological systems in semiarid environments, and the key role of mobile wildlife populations as agents of spatial coupling between the human‐dominated and natural portions of ecosystems. They also underscore the fundamental importance of considering the spatial configuration of hunting refuges across the landscape in relation to human populations.
Soil development and establishment of carbon‐based properties in created freshwater marshes
Authors: Hossler Katie , Bouchard Virginie
Published: March 2010

The current U.S. wetland mitigation policy of “no net loss” requires that a new wetland be created to replace any natural wetland destroyed under development pressures. This policy, however, may be resulting in a net loss of carbon‐based wetland functions. We evaluated the ability of created wetlands to accumulate carbon and to mitigate loss of carbon‐based functions in natural wetlands with variable hydrology. Potential limiting factors to carbon accumulation within created systems included soil aggregation, texture, and bulk density. Rates of soil development and the time required for created wetlands to accumulate the amount of carbon found in natural wetlands were estimated by an exponential model.

Soils collected from five created (ages 3–8 years) and four natural freshwater marshes, located in central Ohio, USA, were analyzed for soil organic carbon (SOC), mineralizable soil carbon (Cmin), water‐stable aggregates (WSA), particle‐size fractions (PSD), and bulk density. Peak‐standing aboveground plant biomass was also quantified. Created wetlands contained significantly less plant biomass, SOC, and Cmin than natural wetlands (α ≤ 0.05; false discovery rate). Soil physical properties also differed significantly between created and natural wetlands, with fewer macroaggregates, more microaggregates, more silt–clay (0–5 cm only), and higher bulk density in created wetlands (α ≤ 0.05; false discovery rate). Carbon content was positively correlated with macroaggregate content and negatively correlated with microaggregate content, silt‐clay fraction, and bulk density.

Fit of SOC data to the exponential model indicated that a newly created wetland would require 300 years to sequester the amount of SOC contained in a natural wetland. At this rate of carbon accumulation, a mitigation ratio of 2.7:1 (area) would be necessary for successful mitigation over a 50‐year time period. However, other trajectories fit the data equally well and suggested area mitigation ratios of 2.2:1 (logistic) to 4.4:1 (linear regression) to 5.1:1 (exponential regression). Whether created wetlands are on a trajectory toward natural wetland carbon function, however, remains uncertain. Until gaps in the data are filled and a trajectory verified, the best mitigation policy will be a conservative one, with a restrictive permitting process and high mitigation ratios (5.1:1 minimum).
Uncertainty propagation in an ecosystem nutrient budget
Authors: Lehrter John C. , Cebrian Just
Published: March 2010

New aspects and advancements in classical uncertainty propagation methods were used to develop a nutrient budget with associated uncertainty for a northern Gulf of Mexico coastal embayment. Uncertainty was calculated for budget terms by propagating the standard error and degrees of freedom. New aspects include the combined use of Monte Carlo simulations with classical error propagation methods, uncertainty analyses for GIS computations, and uncertainty propagation involving literature and subjective estimates of terms used in the budget calculations. The methods employed are broadly applicable to the mathematical operations employed in ecological studies involving step‐by‐step calculations, scaling procedures, and calculations of variables from direct measurements and/or literature estimates. Propagation of the standard error and the degrees of freedom allowed for calculation of the uncertainty intervals around every term in the budget. For scientists and environmental managers, the methods developed herein provide a relatively simple framework to propagate and assess the contributions of uncertainty in directly measured and literature estimated variables to calculated variables. Application of these methods to environmental data used in scientific reporting and environmental management will improve the interpretation of data and simplify the estimation of risk associated with decisions based on ecological studies.
Fire regimes, forest change, and self‐organization in an old‐growth mixed‐conifer forest, Yosemite National Park, USA
Authors: Scholl Andrew E. , Taylor Alan H.
Published: March 2010

Fire is recognized as a keystone process in dry mixed‐conifer forests that have been altered by decades of fire suppression. Restoration of fire disturbance to these forests is a guiding principle of resource management in the U.S. National Park Service. Policy implementation is often hindered by a poor understanding of forest conditions before fire exclusion, the characteristics of forest changes since excluding fire, and the influence of topographic or self‐organizing controls on forest structure. In this study the spatial and temporal characteristics of fire regimes and forest structure are reconstructed in a 2125‐ha mixed‐conifer forest. Forests were multi‐aged, burned frequently at low severity and fire‐return interval, and forest structure did not vary with slope aspect, elevation, or slope position. Fire exclusion has caused an increase in forest density and basal area and a compositional shift to shade‐tolerant and fire‐intolerant species. The median point fire‐return interval and extent of a fire was 10 yr and 115 ha, respectively. The pre‐Euro‐American settlement fire rotation of 13 yr increased to 378 yr after 1905. The position of fire scars within tree rings indicates that 79% of fires burned in the midsummer to fall period. The spatial pattern of burns exhibited self‐organizing behavior. Area burned was 10‐fold greater when an area had not been burned by the previous fire. Fires were frequent and widespread, but patches of similar aged trees were <0.2 ha, suggesting small fire‐caused canopy openings. Managers need to apply multiple burns at short intervals for a sustained period to reduce surface fuels and create small canopy openings characteristic of the reference forest. By coupling explicit reference conditions with consideration of current conditions and projected climate change, management activities can balance restoration and risk management.
Globally downscaled climate projections for assessing the conservation impacts of climate change
Authors: Tabor Karyn , Williams John W.
Published: March 2010

Assessing the potential impacts of 21st‐century climate change on species distributions and ecological processes requires climate scenarios with sufficient spatial resolution to represent the varying effects of climate change across heterogeneous physical, biological, and cultural landscapes. Unfortunately, the native resolutions of global climate models (usually approximately 2° × 2° or coarser) are inadequate for modeling future changes in, e.g., biodiversity, species distributions, crop yields, and water resources. Also, 21st‐century climate projections must be debiased prior to use, i.e., corrected for systematic offsets between modeled representations and observations of present climates. We have downscaled future temperature and precipitation projections from the World Climate Research Programme's (WCRP's) CMIP3 multi‐model data set to 10‐minute resolution and debiased these simulations using the change‐factor approach and observational data from the Climatic Research Unit (CRU). These downscaled data sets are available online and include monthly mean temperatures and precipitation for 2041–2060 and 2081–2100, for 24 climate models and the A1B, A2, and B1 emission scenarios. This paper describes the downscaling method and compares the downscaled and native‐resolution simulations. Sharp differences between the original and downscaled data sets are apparent at regional to continental scales, particularly for temperature in mountainous areas and in areas with substantial differences between observed and simulated 20th‐century climatologies. Although these data sets in principle could be downscaled further, a key practical limitation is the density of observational networks, particularly for precipitation‐related variables in tropical mountainous regions. These downscaled data sets can be used for a variety of climate‐impact assessments, including assessments of 21st‐century climate‐change impacts on biodiversity and species distributions.
Conserving migratory land birds in the New World: Do we know enough?
Authors: Faaborg John , Holmes Richard T. , Anders Angela D. , Bildstein Keith L. , Dugger Katie M. , Gauthreaux Sidney A. , Heglund Patricia , Hobson Keith A. , Jahn Alex E. , Johnson Douglas H. , Latta Steven C. , Levey Douglas J. , Marra Peter P. , Merkord Christopher L. , Nol Erica , Rothstein Stephen I. , Sherry Thomas W. , Sillett T. Scott , Thompson Frank R. , Warnock Nils
Published: March 2010

Migratory bird needs must be met during four phases of the year: breeding season, fall migration, wintering, and spring migration; thus, management may be needed during all four phases. The bulk of research and management has focused on the breeding season, although several issues remain unsettled, including the spatial extent of habitat influences on fitness and the importance of habitat on the breeding grounds used after breeding. Although detailed investigations have shed light on the ecology and population dynamics of a few avian species, knowledge is sketchy for most species. Replication of comprehensive studies is needed for multiple species across a range of areas.

Information deficiencies are even greater during the wintering season, when birds require sites that provide security and food resources needed for survival and developing nutrient reserves for spring migration and, possibly, reproduction. Research is needed on many species simply to identify geographic distributions, wintering sites, habitat use, and basic ecology. Studies are complicated, however, by the mobility of birds and by sexual segregation during winter. Stable‐isotope methodology has offered an opportunity to identify linkages between breeding and wintering sites, which facilitates understanding the complete annual cycle of birds.

The twice‐annual migrations are the poorest‐understood events in a bird's life. Migration has always been a risky undertaking, with such anthropogenic features as tall buildings, towers, and wind generators adding to the risk. Species such as woodland specialists migrating through eastern North America have numerous options for pausing during migration to replenish nutrients, but some species depend on limited stopover locations. Research needs for migration include identifying pathways and timetables of migration, quality and distribution of habitats, threats posed by towers and other tall structures, and any bottlenecks for migration.

Issues such as human population growth, acid deposition, climate change, and exotic diseases are global concerns with uncertain consequences to migratory birds and even less‐certain remedies. Despite enormous gaps in our understanding of these birds, research, much of it occurring in the past 30 years, has provided sufficient information to make intelligent conservation efforts but needs to expand to handle future challenges.
Ecophysiology of riparian cottonwood and willow before, during, and after two years of soil water removal
Authors: Hultine K. R. , Bush S. E. , Ehleringer J. R.
Published: March 2010

Riparian cottonwood/willow forest assemblages are highly valued in the southwestern United States for their wildlife habitat, biodiversity, and watershed protection. Yet these forests are under considerable threat from climate change impacts on water resources and land‐use activities to support human enterprise. Stream diversions, groundwater pumping, and extended drought have resulted in the decline of cottonwood/willow forests along many riparian corridors in the Southwest and, in many cases, the replacement of these forests with less desirable invasive shrubs and trees. Nevertheless, ecophysiological responses of cottonwood and willow, along with associated ecohydrological feedbacks of soil water depletion, are not well understood. Ecophysiological processes of mature Fremont cottonwood and coyote willow stands were examined over four consecutive growing seasons (2004–2007) near Salt Lake City, Utah, USA. The tree stands occurred near the inlet of a reservoir that was drained in the spring of 2005 and remained empty until mid‐summer of 2006, effectively removing the primary water source for most of two growing seasons. Stem sap flux density (Js) in cottonwood was highly correlated with volumetric soil moisture (θ) in the upper 60 cm and decreased sevenfold as soil moisture dropped from 12% to 7% after the reservoir was drained. Conversely, Js in willow was marginally correlated with θ and decreased by only 25% during the same period. Opposite patterns emerged during the following growing season: willow had a lower whole‐plant conductance (kt) in June and higher leaf carbon isotope ratios (δ13C) than cottonwood in August, whereas kt and δ13C were otherwise similar between species. Water relations in both species recovered quickly from soil water depletion, with the exception that sapwood area to stem area (As:Ast) was significantly lower in both species after the 2007 growing season compared to 2004. Results suggest that cottonwood has a greater sensitivity to interannual reductions in water availability, while willow is more sensitive to longer periods of soil water depletion. These data shed light on the linkage between soil water deficits and ecophysiological processes of threatened riparian forests given potential land‐use and long‐term drought impacts on freshwater resources.
Rising stream and river temperatures in the United States
Authors: Kaushal Sujay S , Likens Gene E , Jaworski Norbert A , Pace Michael L , Sides Ashley M , Seekell David , Belt Kenneth T , Secor David H , Wingate Rebecca L
Published: March 2010

Water temperatures are increasing in many streams and rivers throughout the US. We analyzed historical records from 40 sites and found that 20 major streams and rivers have shown statistically significant, long‐term warming. Annual mean water temperatures increased by 0.009–0.077°C yr−1, and rates of warming were most rapid in, but not confined to, urbanizing areas. Long‐term increases in stream water temperatures were typically correlated with increases in air temperatures. If stream temperatures were to continue to increase at current rates, due to global warming and urbanization, this could have important effects on eutrophication, ecosystem processes such as biological productivity and stream metabolism, contaminant toxicity, and loss of aquatic biodiversity.
Rapid responses to facilitate ecological discoveries from major disturbances
Authors: Lindenmayer David B , Likens Gene E , Franklin Jerry F
Published: March 2010

Large‐scale natural disturbances are commonplace around the world. They can have profound effects on human infrastructure and populations, as well as substantially influencing key ecological processes, shaping landscapes, and affecting many species. Major natural disturbances also have the potential to produce important ecological and resource management insights. Here, we argue that it is essential to initiate research quickly after such disturbances, and provide examples illustrating the ecological and management discoveries that arise from the early initiation of post‐disturbance studies. However, there are currently few funding programs available to support this type of rapid research response. Consequently, many ecological and management learning opportunities are lost. We propose ways to address these problems, including: (1) establishing funding programs specifically directed at supporting studies of ecosystem response and recovery after major disturbances, and (2) encouraging scientists to develop plans for studying natural disturbances before they occur.
Ethical and Moral Obligations Arising From Revelations of Pharmaceutical Company Dissembling
Authors: Gottstein James B.
Published: March 2010

The past few years have seen an accelerating series of revelations that the sources of information prescribers of psychotropic medication and other mental health workers have relied on has been corrupted by pervasive pharmaceutical company dissembling. This article discusses the ethical obligations of psychiatrists, psychologists, and social workers that may arise from these revelations. The conclusion is that psychiatrists, psychologists, and social workers have not only the ethical obligation to change the information they are providing clients/patients and other decision makers but also the ethical obligation to insist that this dissembling no longer be tolerated and to hold their leadership accountable.
Treatment of Percolate from Metal Sulfide Mine Tailings with a Permeable Reactive Barrier of Transformed Red Mud
Authors: Zijlstra J.J.P. , Dessì R. , Peretti R. , Zucca A.
Published: March 2010

Metal sulfide tailings of the Sardinian (Italy) abandoned Baccu Locci arsenic mine show high concentrations of aluminum, arsenic, cadmium, copper, manganese, lead, and zinc in acid percolate (pH = 4) and have been classified as “dangerous waste.” This paper shows that the release of toxic metals can be strongly reduced when the tailings are placed on a reactive permeable bed (7 wt %) of porous, alkaline pellets of transformed red mud (TRM). During a laboratory percolation test, two columns with 80 kg of waste, of which one contained a bottom layer of TRM pellets, were each alimented with 600 L of de‐ionized water. Comparing pH, electroconductivity, metal, and sulfate concentrations of collected percolate from both columns demonstrates efficient neutralization (pH = 7.4) and removal of metals (80 to 99%) for the column with the permeable reactive bottom layer.
Statistical Investigations into Indicator Bacteria Concentrations in Houston Metropolitan Watersheds
Authors: Desai Anuradha M. , Rifai Hanadi , Helfer Emil , Moreno Norma , Stein Ron
Published: March 2010

Bacterial pollution in the Houston metropolitan area (Texas) watersheds was studied using statistical methods to determine the Escherichia coli levels and causes of their spatial and temporal variability. Houston bayous generally exhibit elevated E. coli concentrations. The more urban watersheds had higher concentration ranges and geometric means and had more spatial variation with higher overall ranges at downstream monitoring stations. They also were less sensitive to temperature variations and more strongly influenced by rainfall events. The median flow in the more urban bayous is predominantly wastewater. Frequent rainfall in the region, combined with relatively long travel times in the bayous, results in elevated bacterial levels in the bayous. Multiple regression models using water quality parameters were more representative on the segment level and not at the watershed level and may not be useful for predictions that rely on conventional water quality measures, particularly in urban watersheds, such as those studied here. Cluster analysis for the segments resulted in two distinct clusters differentiated by their developed land‐use, population density, domestic animal density, and grassy land‐use.
Use of Ozone‐Based Processes for the Removal of Pharmaceuticals Detected in a Wastewater Treatment Plant
Authors: Kim Ilho , Tanaka Hiroaki
Published: March 2010

Ozone (O3)‐based processes (O3, O3/H2O2, and O3/UV) were investigated for the removal of pharmaceuticals in real wastewater using a bench‐scale experimental setup. An ozone dose of 6 mg/L (contact time = 10 minutes) was found to reduce the concentration of most pharmaceuticals detected in secondary effluent. Caffeine, N,N‐Diethyl‐meta‐toluamide (DEET), and cyclophosphamide were removed with efficiencies of 84, 89, and 46%, respectively, even with a contact time of 15 minutes (O3 dose = 6 mg/L). In the case of the ozone process alone, the concentration of bromate ion in the effluent increased with longer contact time. On the other hand, it was found that the O3/H2O2 and O3/UV processes can be used as alternative processes for effective removal of pharmaceuticals, while leaving a low residual concentration of dissolved ozone in the system, thereby preventing bromate formation.
Mercury Species in Seawater and Sediment of Xiamen Western Sea Area Adjacent to a Coal‐fired Power Plant
Authors: Liang Ying , Liu Xiyao , Yuan Dongxing , Gong Zhebin , Zhang Zhen
Published: March 2010

The purpose of this study was to investigate the concentrations and spatial distributions of mercury (Hg) species in seawater (including dissolved, particle, and total Hg) and sediment (including total and methyl Hg) of the Xiamen western sea area adjacent to a coal‐fired power plant. The influence of the wastewater discharged from the seawater desulphurization (De‐SO2) system of the power plant is discussed. Concentration of the three species of mercury in seawater from 18 sampling sites varied: dissolved ranged from 0.70 to 4.65 ng/L (mean 1.47 ng/L; median 1.12 ng/L); particulate ranged from not detected to 90.52 ng/L (mean 10.47 ng/L; median 1.26 ng/L); and total was 1.51 to 92.88 ng/L (mean 11.94 ng/L; median 2.84 ng/L). High concentrations of total Hg and particulate Hg, more than 70 ng/L, were observed in the area adjacent to the outfalls of the power plant. The Hg from the waste seawater of the power plant might be re‐emitted to the atmosphere because it exists in seawater mainly in particulate attached form. The sediment total Hg concentrations ranged from 0.055 to 0.201 µg/g, with a mean of 0.126 µg/g and a median of 0.125 µg/g. Low methyl Hg concentrations in the sediment were observed in the study area, ranging from 0.017 to 0.256 ng/g as Hg, with a mean of 0.087 ng/g and a median of 0.081 ng/g. The ratios of methyl Hg to total Hg in the sediment were low, with a mean and median of 0.069%. Both total and methyl Hg were significantly linked to the sediment organic carbon (SOC).
Byproduct Recovery from Reclaimed Water Reverse Osmosis Concentrate Using Lime and Soda‐Ash Treatment
Authors: Mohammadesmaeili Farah , Badr Mostafa Kabiri , Abbaszadegan Morteza , Fox Peter
Published: March 2010

Lime and soda‐ash softening of reclaimed water reverse osmosis concentrates as a pretreatment step for concentration by seawater reverse osmosis was the focus of this study. The objectives were removal of the potential fouling minerals of calcium, magnesium, and silica by selective precipitation, while producing byproducts with potential resale value. Three different bench‐scale lime‐soda processes were evaluated. The traditional method produced low‐quality magnesium hydroxide [Mg(OH)2] and calcium carbonate (CaCO3) byproducts. A modified process with pre‐acidification to eliminate carbonate removed 98 to 99% of calcium and magnesium and produced CaCO3 that was >94% pure. To prevent the contamination of byproducts with calcium sulfate (CaSO4) in high‐sulfate concentrates, a CaSO4 crystallization step was added successfully to the modified process to precipitate CaSO4 before Mg(OH)2 precipitation and produce gypsum that was 92% pure. The modified lime‐soda process also removed 94 to 97% silica, 72 to 77% barium, and 95 to 96% strontium, which are known as reverse osmosis membrane foulants.
A Potential New Method for Determination of the Fluence (UV Dose) Delivered in UV Reactors Involving the Photodegradation of Free Chlorine
Authors: Feng Yangang , Smith Daniel W. , Bolton James R.
Published: March 2010

In the operation of UV reactors, an important step is to validate if the UV reactor can deliver the design fluence (UV dose) to achieve the required disinfection credit. Free chlorine is used widely in water and wastewater treatment and often is found in the water passing through a UV reactor. Free chlorine is degraded when passing through a UV reactor. This study investigates the potential application of the photodegradation of free chlorine (PFC) to determine the fluence (UV dose) delivered in UV reactors. Using a bench‐scale UV reactor, the PFC was investigated at difference UV doses, which also were measured by a biodosimetry method. The results obtained here show that the PFC method has a high correlation with the delivered UV dose (as estimated from the biodosimetry measurements) and is independent of operating conditions, such as flowrate and UV transmittance. In addition, this study indicates that only chloride and chlorate are generated when free chlorine is photodegraded.
Comparison of Endocrine Response to Stress Between Captive‐Raised and Wild‐Caught Bighorn Sheep
Authors: COBURN SARAH , SALMAN MO , RHYAN JACK , KEEFE THOMAS , MCCOLLUM MATTHEW , AUNE KEITH , SPRAKER TERRY , MILLER LOWELL
Published: March 2010

ABSTRACT  Stress hormones in Rocky Mountain bighorn sheep (Ovis canadensis canadensis), produced in response to environmental changes, road development, or high population density, may impact their immune systems to a threshold level that predisposes them to periodic, large‐scale mortality. We compared the stress response to a novel environmental situation and repeated handling between bighorn sheep born and raised in captivity (CR) and bighorn sheep born in the wild (WC) and brought into captivity. We measured plasma epinephrine, norepinephrine, cortisol, and fecal glucocorticoid metabolites (FGM). Three weeks after each group's arrival we used a one‐time drop‐net event to elicit an acute stress response, and we collected blood samples from each sheep over 35 minutes, as well as one fecal sample. We collected blood and fecal samples from both groups on 7 other occasions over the subsequent 6 months. We also collected fecal samples from the pen at approximately 24‐hour intervals for 3 days following every handling event to monitor the stress response to handling. We found that CR sheep had a stronger autonomic nervous system response than WC sheep, as measured by epinephrine and norepinephrine levels, but we found a very similar hypothalamic‐pituitary–adrenal axis (HPA) response, measured by cortisol levels, to the acute stress event of a drop‐net restraint. We also found that once the WC sheep had acclimated, as indicated by the return to the initial baseline FGM levels within 12 weeks, the CR and WC groups' HPA responses to sampling events were not significantly different from one another. Fecal samples can provide a noninvasive mechanism for managers to monitor baseline FGM for a given herd. Using long‐term monitoring of FGM rather than values from a single point in time may allow managers to correlate these levels to outside influences on the herd and better understand the impacts of management changes, population density, or increased human developments on the health of the sheep population.
Effects of Experimental Canopy Manipulation on Amphibian Egg Deposition
Authors: FELIX ZACHARY I. , WANG YONG , SCHWEITZER CALLIE J.
Published: March 2010

ABSTRACT  Although effects of forest management on amphibians are relatively well studied, few studies have examined how these practices affect egg deposition by adults, which can impact population recruitment. We quantified the effects of 4 canopy tree‐retention treatments on amphibian oviposition patterns in clusters of 60‐L aquatic mesocosms located in each treatment. We also related aquatic and terrestrial biophysical parameters in treatment plots to oviposition patterns. Cope's gray treefrogs (Hyla chrysoscelis) deposited more egg masses in clear‐cut and 25–50% tree‐retention treatments than in controls. In contrast, mountain chorus frogs (Pseudacris brachyp***hona) deposited more egg masses in unharvested control and 75% retention treatments than in clear‐cut or 25–50% retention treatments. Spotted salamanders (Ambystoma maculatum) only deposited eggs in 75% retention treatments and controls. The number of egg masses deposited by mountain chorus frogs was positively related to canopy cover and negatively related to water temperature, pH, and dissolved oxygen, whereas we noted the opposite relationships for Cope's gray treefrogs. We did not detect a relationship between the number of egg masses deposited by any species and the distance of mesocosms to either the nearest mature closed‐canopy forest or to the nearest natural amphibian breeding pool. The impacts of the silvicultural treatments we studied were species‐specific and depended on the amount of trees removed. In areas where protection of spotted salamander and mountain chorus frog breeding habitat is a priority, we recommend harvests retain at least 75% of the canopy. Our results also suggest that retention of 25–50% of canopy trees surrounding amphibian breeding pools has little conservation benefit.
Thresholds and Time Lags in Effects of Energy Development on Greater Sage‐Grouse Populations
Authors: HARJU SETH M. , DZIALAK MATTHEW R. , TAYLOR RENEE C. , HAYDEN‐WING LARRY D. , WINSTEAD JEFFREY B.
Published: March 2010

ABSTRACT  Rapid expansion of energy development in some portions of the Intermountain West, USA, has prompted concern regarding impacts to declining greater sage‐grouse (Centrocercus urophasianus) populations. We used retrospective analyses of public data to explicitly investigate potential thresholds in the relationship between lek attendance by male greater sage‐grouse, the presence of oil or gas wells near leks (surface occupancy), and landscape‐level density of well pads. We used generalized linear models and generalized estimating equations to analyze data on peak male attendance at 704 leks over 12 years in Wyoming, USA. Within this framework we also tested for time‐lag effects between development activity and changes in lek attendance. Surface occupancy of oil or gas wells adjacent to leks was negatively associated with male lek attendance in 5 of 7 study areas. For example, leks that had ≥ 1 oil or gas well within a 0.4‐km (0.25‐mile) radius encircling the lek had 35–91% fewer attending males than leks with no well within this radius. In 2 of these 5 study areas, negative effects of well surface occupancy were present out to 4.8 km, the largest radius we investigated. Declining lek attendance was also associated with a higher landscape‐level density of well pads; lek attendance at well‐pad densities of 1.54 well pads/km2 (4 well pads/mile2) ranged from 13% to 74% lower than attendance at unimpacted leks (leks with zero well pads within 8.5 km). Lek attendance at a well‐pad density of 3.09 well pads/km2 (8 well pads/mile2) ranged from 77% to 79% lower than attendance at leks with no well pad within 8.5 km. Further, our analysis of time‐lag effects suggested that there is a delay of 2–10 years between activity associated with energy development and its measurable effects on lek attendance. These results offer new information for consideration by land managers on spatial and temporal associations between human activity and lek attendance in sage‐grouse, and suggest that regional variation is an important consideration in refining existing management strategies.
Evaluating Basking‐Habitat Deficiency in the Threatened Eastern Massasauga Rattlesnake
Authors: SHOEMAKER KEVIN T. , GIBBS JAMES P.
Published: March 2010

ABSTRACT  Woody plant succession is hypothesized to threaten many reptile populations by reducing the amount of solar energy available for thermoregulation. Mitigation via vegetation management is often recommended; however, the need for such management practices rarely has been evaluated. We examined the need for basking‐site enhancement for the eastern massasauga rattlesnake (Sistrurus c. catenatus; hereafter EMR) in New York, USA, where only 2 populations remain: one at an open‐canopy site and another at a closed‐canopy site. Microhabitat temperatures were substantially lower at the closed‐canopy site, where EMRs selected the warmest available basking sites. Eastern massasauga rattlesnakes in the open‐canopy population selected basking sites that afforded greater cryptic cover. We recommend experimental reduction of shrub cover to improve EMR basking habitat at the closed‐canopy site. More generally, we caution that management efforts to reduce shrub cover for basking EMRs should maintain adequate cryptic cover.
Female Harlequin Duck Winter Survival 11 to 14 Years After the Exxon Valdez Oil Spill
Authors: ESLER DANIEL , IVERSON SAMUEL A.
Published: March 2010

ABSTRACT  In the mid‐ to late 1990s, nearly a decade after the 1989 Exxon Valdez oil spill, female harlequin ducks (Histrionicus histrionicus) suffered reduced winter survival in oiled areas of Prince William Sound, Alaska, USA, relative to unoiled areas. We conducted follow‐up studies from winters 2000–2001 to 2002–2003 to determine whether differential survival persisted and to evaluate whether individual‐level indices of oil exposure were related to survival. Using radiotelemetry, we tracked 138 female harlequin ducks from November through March over three winters. We analyzed variation in survival in relation to season, area oiling history, age class, body mass, and an index to exposure to residual oil based on cytochrome P4501A (CYP1A) induction. We determined that survival was most strongly related to season and age class, with evidence of higher survival in late winter and after hatch year (AHY) categories, respectively. We estimated cumulative winter survival for AHY females to be 0.837 (±0.064) and 0.834 (±0.065) on unoiled and oiled areas, respectively, and we estimated hatch‐year female cumulative winter survival at 0.766 (±0.138) on unoiled areas and 0.758 (±0.152) on oiled areas. Despite persistence of oil in some intertidal areas and evidence of contaminant ingestion by harlequin ducks during and beyond this study, neither area nor CYP1A were strongly related to variation in survival, suggesting that direct effects of the oil spill on harlequin duck demography had largely abated by the winters 2000–2001 to 2002–2003. Our findings offer an unprecedented description of the timeline of effects of exposure to spilled oil and contribute to a body of literature that describe demographic effects of the Exxon Valdez oil spill that persisted over a much longer time than previously assumed. An appreciation for the timescale of chronic effects of oil spills, as well as potential for demographic effects related to much lower concentrations of oil than during the immediate period of acute effects following a spill, will provide wildlife managers with a basis for risk assessment and plans for mitigation when confronted with large spills or chronic pollution.