bluuebunny/crossref_metadata_2025 huggingface dataset:
Computation of Shock Induced Noise in Imperfectly Expanded Supersonic Jets
Authors: Imamoglu B. , Baysal O. , Balakumar P.
Published: June 2007

Screech noise exists in imperfectly expanded jets. When the exit pressure of imperfectly expanded jet does not match its backpressure, expansion or compression waves appear out of the nozzle and generate shock cell patterns. Screech is generated by the interaction of shock cells and instability waves. Although many studies have been conducted to model screech noise, it still is not yet a well-understood phenomenon.

In the present computational study, the results help better understand screech generation mechanisms and they are compared with the latest available experiments. First, axisymmetric models are constructed for underexpanded jets of 25.4 mm diameter and Mach numbers of 1.19 and 1.43. Then, three dimensional (3D) models are computed for jets with Mach numbers of 1.43 and 1.80. The mathematical model consists of full Navier-Stokes equations in cylindrical coordinates, and large-eddy-simulation turbulence modeling. For spatial discretizations, a fifth-order, weighted essentially non-oscillatory scheme is used, as it is deemed the most suitable method for capturing shocks. Time discretization is a third-order total-variation-diminishing scheme. This methodology does not require artificial viscosity or “tuning up” of parameters.

The experimental results predict that the solution is in axisymmetric mode for Mach 1.19 and in helical mode for 1.43. The experimental screech frequencies of 8.4 kHz for Mach 1.19 and 5.4 kHz for Mach 1.43 are verified with the present axisymmetric results. Computed shock cell structure is in agreement with experiments and other published computations in all cases. As in the experiments, the present screech waves emerge from the second and third shock cells. The screech wavelength is roughly estimated as 1.5 D, which is close to other published computational studies. Axisymmetric results for Mach number 1.43 could predict general flow quantities, like shock cell pattern and screech frequency prediction. Therefore, three-dimensional helical effects are investigated by creating a simulation of planes with varying azimuthal angles. This has been useful to detect shock generation locations. In Mach 1.80 case, a barrel shock structure is observed just as in the experimental studies. In conclusion, this study is deemed as a good verification of experimental results.
A Behavioral Theory of the Firm—40 Years and Counting: Introduction and Impact
Authors: Argote Linda , Greve Henrich R.
Published: June 2007

In this introductory piece, we take stock of the impact of Cyert and March’s A Behavioral Theory of the Firm, describe current research trends in the behavioral tradition, and introduce the special issue’s papers. A Behavioral Theory of the Firm is one of the most influential management books of all time. In the book, Cyert and March developed theoretical building blocks that became the foundations for current research in organizational studies in management, economics, political science, and sociology. Cyert and March also made theoretical propositions that are investigated and extended in current work on organizational learning theory and evolutionary economics.
Synthesis, characterization, thermal stability and redox behavior of In3+2Ti4+1–xTm3+xO5–δ, (Tm = Fe3+ and Cr3+, 0.0 ≤ x ≤ 0.2) mixed-oxide catalysts
Authors: Pai M.R. , Banerjee A.M. , Bharadwaj S.R. , Kulshreshtha S.K.
Published: June 2007

Mixed metal oxide catalysts with nominal compositions of In2Ti1–xFexO5–δ, In2Ti1–xCrxO5–δ, where 0.0 ≤ x ≤ 0.2, have been synthesized by the ceramic route and characterized using the powder x-ray diffraction technique. The In2Ti1–xFexO5–δ samples were single-phase compositions, isomorphic with In2TiO5 phase. The particle size of the In2Ti1–xFexO5–δ samples was lower compared to the parent In2TiO5 oxide. Thermal stability (by thermogravimetry-differential thermal analysis) in varying atmospheres, and temperature-programmed reduction (TPR)/temperature-programmed oxidation cycles have been recorded to investigate their redox behavior as a function of the value of x in this study. The amount of H2 consumed under TPR curves was correlated with the nonstoichiometry generated in the In2Ti1–xFexO5–δ samples. Fe substitution induced ease in the reducibility (i.e., maximum temperature) of the substituted oxides compared to that in In2TiO5. X-ray photoelectron spectroscopy has been used to confirm the oxidation states of indium and other metal ions in fresh and reduced samples.
Smart electrodes for ultralarge-area thin film capacitors
Authors: Daniels Patrick , Ihlefeld Jon , Borland William , Maria Jon-Paul
Published: June 2007

A process suitable for preparing metal-insulator-metal thin film capacitors with submicron insulating layers and top electrodes with cm-scale dimensions is presented. Most importantly, this process does not require sophisticated deposition equipment or a clean room environment. The key to large area yield is co-firing the insulator film with a non-dewetting electrode during the dielectric crystallization/densification anneal. We propose a mechanism of electrode dewetting during the high temperature anneal where the metal laterally retreats from geometric asperities that compromise the integrity of the insulating layer. This behavior is driven by surface energy minimization, which promotes metal migration away from the regions of high curvature. This methodology is not material specific, and only requires a top electrode with a large contact angle to the dielectric in question. Using this technique, functional thin film capacitors with 2.5 cm lateral dimensions and 1 μm dielectric thicknesses can be routinely prepared.
Chelated Potassium and Arginine Supplementation in Diets of Pacific White Shrimp Reared in Low-Salinity Waters of West Alabama
Authors: Saoud I Patrick , Roy Luke A , Davis D Allen
Published: June 2007

Dietary supplements have been proposed as a potential remediation strategy to counteract mineral deficiencies in low-salinity well waters (LSWW) used for shrimp culture in Alabama. Existing strategies (i.e., application of fertilizers such as K-mag and muriate of potash) are costly to farmers attempting to raise levels of potassium (K+) in their ponds. Previous laboratory studies using dietary supplements of chelated K+ increased growth but not survival of Pacific white shrimp Litopenaeus vannamei reared in low-salinity water. To determine whether this approach is applicable in the field, two growth trials were conducted in flow-through outdoor tanks that used water from farm ponds. The first trial (6 weeks) was conducted simultaneously at two separate low-salinity farms in west Alabama and evaluated two practical diets, one with a chelated K+ supplement and one without. One of these farms supplements K+ to its water and is considered a low-stress environment (LSE), while the other farm does not supplement its water and is considered a high-stress environment (HSE). Results indicated that dietary supplementation of K+ (1.0%) in the absence of an appropriate ionic profile (i.e., the HSE) failed to enhance growth or survival of Pacific white shrimp. Another 9-week growth trial was conducted at the LSE farm. Shrimp were offered either a practical basal diet or the basal diet supplemented with 0.5% chelated K+, 1.0% chelated K+, or 0.4% arginine. Although no statistically significant effects of chelated K+ supplementation were observed, results of this experiment and two other experiments showed an increase in growth associated with chelated K+ supplementation, indicating a marginal benefit. Present results do not justify K+ supplementation of diets for Pacific white shrimp reared in inland LSWW. Better shrimp survival and growth are observed when K+ is added to culture waters to mitigate imbalances in Na:K and Cl:K ratios.
Estimating Seasonal Movements of Chinook Salmon in Lake Huron from Efficiency Analysis of Coded Wire Tag Recoveries in Recreational Fisheries
Authors: Adlerstein Sara A. , Rutherford Edward S. , Clapp David , Clevenger John A. , Johnson James E.
Published: June 2007

The decline of hatchery-reared Chinook salmon Oncorhynchus tshawytscha stocks in Lakes Huron and Michigan during the 1980s prompted mass-tagging programs to investigate reproduction, poststocking survival, and movements. In Lake Huron, millions of smolts implanted with coded wire tags (CWTs) were released in Michigan waters and recovered from charter and noncharter fisheries, surveys, and weirs. Using generalized linear models (GLMs), we investigated Chinook salmon seasonal movements based on the spatial and temporal distributions of recoveries by fishing trips in U.S. recreational fisheries and recovery efficiency. We used models incorporating area, month, year, and recovery source; creel-clerk and “headhunter” (CWT collection specialist) samples; and charter captain reports. We implemented models for recoveries regardless of release area and from one particular area. All model predictors and interactions between month and area were significant. The variation in recovery levels among recovery sources was larger than temporal or spatial variation. Headhunters were 7 times more efficient than captains in recovering CWTs from charter-boat catch and 11 times more efficient than clerks in recovering CWTs from non-charter-boat catch; this was due to the higher catches experienced in charter than in noncharter trips and to different recovery program goals. The spatial and temporal distribution of GLM-standardized recovery levels suggested that Chinook salmon released along the western coast of Lake Huron moved near shore during early spring and north during summer, returning mostly to nearby stocking areas in summer and fall. To complement our GLM analysis, we evaluated the distributions of CWT salmon released and recovered in U.S. and Canadian waters by all sources. Data supported previous conclusions on longitudinal movements and indicated that in spring fish moved from eastern locations to near shore in western Lake Huron then back to overwinter locations in autumn. These movement patterns coincided with seasonal prey species concentrations and favorable temperatures. The implications of our results for salmon fisheries management and the design of future tagging studies are discussed.
Direct and Indirect Estimates of Natural Mortality for Chesapeake Bay Blue Crab
Authors: Hewitt David A. , Lambert Debra M. , Hoenig John M. , Lipcius Romuald N. , Bunnell David B. , Miller Thomas J.
Published: June 2007

Analyses of the population dynamics of blue crabCallinectes sapidushave been complicated by a lack of estimates of the instantaneous natural mortality rate (M). We developed the first direct estimates ofMfor this species by solving Baranov's catch equation forMgiven estimates of annual survival rate and exploitation rate. Annual survival rates were estimated from a tagging study on adult female blue crabs in Chesapeake Bay, and female‐specific exploitation rates for the same stock were estimated by comparing commercial catches with abundances estimated from a dredge survey. We also used eight published methods based on life history parameters to calculate indirect estimates ofMfor blue crab. Direct estimates ofMfor adult females in Chesapeake Bay for the years 2002–2004 ranged from 0.42 to 0.87 per year and averaged 0.71 per year. Indirect estimates ofMvaried considerably depending on life history parameter inputs and the method used. All eight methods yielded values forMbetween 0.99 and 1.08 per year, and six of the eight methods yielded values between 0.82 and 1.35 per year. Our results indicate that natural mortality of blue crab is higher than previously believed, and we considerMvalues between 0.7 and 1.1 per year to be reasonable for the exploitable stock in Chesapeake Bay. Remaining uncertainty aboutMmakes it necessary to evaluate a range of estimates in assessment models.
Recovery of nontarget Lepidoptera on Vancouver Island, Canada: One and four years after a gypsy moth eradication program
Authors: Boulton Timothy J. , Otvos Imre S. , Halwas Karen L. , Rohlfs Doris A.
Published: June 2007

The gypsy moth (Lymantria dispar) is a destructive defoliator that is not established in British Columbia, Canada, because of successful eradication programs involving the microbial insecticide Bacillus thuringiensis var. kurstaki (Btk). In 1999, three aerial applications of Btk were made over two areas, totaling 12,805 ha, on southern Vancouver Island, Canada. The impacts of these Btk applications on nontarget Lepidoptera were studied from 1999 to 2004on Garry oak (Quercus garryana) and common snowberry (Symphoricarpos albus). In 1999, lepidopteran larvae were collected from S. albus foliage at 24 urban parks and from Q. garryana foliage at 28 oak-dominated habitats. The initial impacts (i.e., 1999 data) were published previously, and the present paper is a continuation of the same study. We tested two hypotheses: Reductions of nontarget Lepidoptera would be more severe at 12 to 13 months postspray than at one to two months postspray, and recovery would be significant, though not necessarily complete, at four years postspray. The total number of nontarget Lepidoptera on S. albus and Q. garryana was significantly reduced in the treatment sites in each year of the study: the reduction was greatest in 2000. Relative to the reference sites, each of 11 species that were initially reduced by the Btk applications showed an increase in the treatment sites between 2000 and 2003, by which time only four species remained significantly reduced in the treatment sites. The uncommon species were significantly reduced in 1999 and 2000 but not in 2003, indicating that some recovery had occurred. Limitations and economic implications of the present study are discussed.
Impact of polychlorinated biphenyl and polycyclic aromatic hydrocarbon sequestration in sediment on bioaccumulation in aquatic food webs
Authors: Moermond Caroline T.A. , Roessink Ivo , Jonker Michiel T.O. , Meijer Thijs , Koelmans Albert A.
Published: June 2007

It is not clear whether sequestration or aging of organic chemicals like polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) limits accumulation in higher levels of aquatic food chains. Therefore, the effect of aging on accumulation was studied in 1-m3 model ecosystems that mimicked fish-dominated, macrophyte-dominated, and fish- and macrophyte-dominated shallow lakes. Also treatments without fish and macrophytes were included. General characteristics, biomasses, total (Soxhlet-extractable), and labile (6-h Tenax-extractable) PCB and PAH concentrations in sediment and biota were monitored over time. Accumulation data for PCB 28, PCB 149, and fluoranthene (native to the sediment taken from the field) were compared to those for spiked analogues PCB 29, PCB 155, and fluoranthene-d10. Labile fractions for spiked compounds were higher than for their native analogues and decreased over time, suggesting sequestration in the sediment. In the majority of cases, 6-h Tenaxextractable concentrations correlated better with concentrations in biota than Soxhlet-extractable concentrations. Ecosystem structure affected food web accumulation, but replicate variability was too high to detect clear treatment effects. Differences in accumulation between spiked compounds and their native analogues indicated an effect of aging for invertebrates, macrophytes, and benthivorous fish. Thus, aging may translate directly into reduced uptake at higher trophic levels.
Evaluating regional predictive capacity of a process-based mercury exposure model, regional-mercury cycling model, applied to 91 Vermont and New Hampshire lakes and ponds, USA
Authors: Knightes Christopher D. , Ambrose Robert B.
Published: June 2007

Regulatory agencies must develop fish consumption advisories for many lakes and rivers with limited resources. Process-based mathematical models are potentially valuable tools for developing regional fish advisories. The regional mercury cycling model (R-MCM) specifically was designed to model a series of lakes for a given region with site-specific data and parameterization for each application. In this paper, we explore the feasibility of R-MCM application to develop regional fish advisories from existing data by testing model performance across 91 Vermont ([VT], USA) and New Hampshire ([NH], USA) lakes. We use a progressive method of parameter refinement ranging from simple defaults specified by the model to site-specific parameterization to evaluate potential improvements in model prediction. Model applications and parameter refinement tiers are based on Regional Environmental Monitoring Assessment Program (REMAP) data. Results show that R-MCM generally underpredicts water column methylmercury and total mercury concentrations and overpredicts sediment methylmercury concentrations. Default level input parameterization produced the largest amount of random scatter in model forecasted values. Using site-specific values for the default level characteristics reduced this variability but did not improve overall model performance. By separating the observed and predicted data by lake characteristics, we identify some overall trends in bias and fit, but are unable to identify systematic biases in model performance by lake type. This analysis suggests that process-based models like R-MCM cannot be used for a priori predictive applications at the regional scale at this time. Further, this work reinforces the need for additional research on the transport and transformation of mercury to elucidate parameterization useable in a modeling framework to help refine predictive capabilities of process-based models.
Size-dependence of the potential for metal biomagnification in early life stages of marine fish
Authors: Zhang Li , Wang Wen-Xiong
Published: June 2007

We investigated the bioaccumulation of metals (Cd, Se, and Zn) in different juvenile sizes of black sea bream Acanthopagrus schlegeli by applying a biokinetic model. A series of experiments were conducted to determine the physiological kinetic parameters, including uptake rate constant of waterborne metals, ingestion rate, assimilation efficiency of dietary metals, efflux rate constant, and specific growth rate as a function of fish size. Body concentration of metals as a function of body size was then simulated by the kinetic model and compared with the actual measurements. The uptake rate constants decreased with increasing fish size, with an allometric exponent (b) of 0.615 to 0.662. Ingestion rate was also negatively correlated with the fish size (b = −0.604). Assimilation efficiencies of Cd were independent of body size, whereas those of Se and Zn increased with fish size. In contrast, efflux rate constants and growth rate constants for metals were comparable in different sizes of fish. Predicted concentrations of Cd and Zn were comparable to actual measurements and were negatively correlated with fish size. Ingestion rate was the most important parameter accounting for the size-dependent bioaccumulation of metals, followed by dietary assimilation. We further showed that the trophic transfer potentials of Se and Zn were >1 in smaller fish but then reduced to <1 in larger ones, suggesting that trophic transfer potentials are highly size dependent in marine fish.
Plasma to egg conversion factor for evaluating polychlorinated biphenyl and DDT exposures in great horned owls and bald eagles
Authors: Strause Karl D. , Zwiernik Matthew J. , Im Sook Hyeon , Newsted John L. , Kay Denise P. , Bradley Patrick W. , Blankenship Alan L. , Williams Lisa L. , Giesy John P.
Published: June 2007

The benefits of nondestructive sampling techniques, such as plasma sampling, to directly measure contaminant exposure levels in at-risk or protected raptor populations are many. However, such assays are generally inconsistent with the most certain source of toxicity reference values, which are based on feeding studies and quantified as dietary or “in ovo” (egg-based) concentrations. An accurate conversion factor to translate nondestructive plasma-based contaminant concentrations to comparable egg-based concentrations will prove valuable to risk assessors investigating the potential effects of chemical exposures to raptors. We used databases describing the concentrations of total polychlorinated biphenyls (PCBs) in great horned owls (GHO; Bubo virginianus) and total PCBs and p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE) in bald eagles (Haliaeetus leucocephalus) from the Great Lakes region (Michigan, Wisconsin, USA) to develop a relationship to predict concentrations of PCBs and DDE in eggs. To develop a robust predictive relationship, all of the source data included concentrations of both total PCBs and/or DDE for nestling blood plasma and egg samples collected from within discrete active nesting territories and, in most instances, the same nest. The key characteristics (slope and elevation) of each relationship were tested for differences related to species and geographic region. Predicted variability of relationships were examined and compared to variability associated with natural systems. The results of statistical testing indicate that applying the conversion factors between species (GHO to bald eagle) and among geographic regions yields predicted egg concentrations that are not statistically dissimilar and are within the natural variability observed for residue concentrations among eggs of raptors within species and region.
Effects of brominated flame retardants and brominated dioxins on steroidogenesis in H295R human adrenocortical carcinoma cell line
Authors: Ding Ling , Murphy Margaret B. , He Yuhe , Xu Yan , Yeung Leo W.Y. , Wang Jingxian , Zhou Bingsheng , Lam Paul K.S. , Wu Rudolf S.S. , Giesy John P.
Published: June 2007

Brominated flame retardants (BFRs) and brominated dioxins are emerging persistent organic pollutants that are ubiquitous in the environment and can be accumulated by wildlife and humans. These chemicals can disturb endocrine function. Recent studies have demonstrated that one of the mechanisms of endocrine disruption by chemicals is modulation of steroidogenic gene expression or enzyme activities. In this study, an in vitro assay based on the H295R human adrenocortical carcinoma cell line, which possesses most key genes or enzymes involved in steroidogenesis, was used to examine the effects of five bromophenols, two polybrominated biphenyls (PBBs 77 and 169), 2,3,7,8-tetrabromodibenzo-p-dioxin, and 2,3,7,8-tetrabromodibenzofuran on the expression of 10 key steroidogenic genes. The H295R cells were exposed to various BFR concentrations for 48 h, and the expression of specific genes—cytochrome P450 (CYP11A, CYP11B2, CYP17, CYP19, and CYP21), 3β-hydroxysteroid dehydrogenase (3βHSD2), 17β-hydroxysteroid dehydrogenase (17βHSD1 and 17βHSD4), steroidogenic acute regulatory protein (StAR), and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR)—was quantitatively measured using real-time polymerase chain reaction. Cell viability was not affected at the doses tested. Most of the genes were either up- or down-regulated, to some extent, by BFR exposure. Among the genes tested, 3βHSD2 was the most markedly up-regulated, with a range of magnitude from 1.6- to 20-fold. The results demonstrate that bromophenol, bromobiphenyls, and bromodibenzo-p-dioxin/furan are able to modulate steroidogenic gene expression, which may lead to endocrine disruption.
Inorganic mercury detection by valve closure response in the freshwater clamCorbicula fluminea: Integration of time and water metal concentration changes
Authors: Tran Damien , Fournier Elodie , Durrieu Gilles , Massabuau Jean-Charles
Published: June 2007

The objective of the present study was to monitor water-quality assessment by a biological method. Optimum dissolved inorganic mercury sensitivity in the freshwater bivalve Corbicula fluminea was estimated using a combined approach to determine their potentials and limits in detecting contaminants. Detection by bivalves is based on shell closure, a protective strategy when exposed to a water contaminant. To take the rate of spontaneous closures into account, stress associated with fixation by one valve in common valvometers was integrated, and the spontaneous rhythm was associated with daily activity. The response in conditions where the probability of spontaneous closing is the lowest was thus taken into account. To develop dose–response curves, impedance valvometry, in which lightweight impedance electrodes are applied to study free-ranging animals in low-stress conditions, also was used combined with a new analytical approach. The logistic regression dose–response curves take into account variations in both response time and metal concentration in water to significantly improve the methods aiming at determining the optimal sensitivity threshold response. This approach demonstrates that in C. fluminea, inorganic mercury concentrations under the range of 2.0 to 5.1 μg/L (95% confidence interval) cannot be detected within 5 h of addition.
Biogeochemical factors affecting mercury methylation in sediments of the Venice Lagoon, Italy
Authors: Han Seunghee , Obraztsova Anna , Pretto Patrizia , Choe Key-Young , Gieskes Joris , Deheyn Dimitri D. , Tebo Bradley M.
Published: June 2007

Mercury methylation and sulfate reduction rates, total Hg, and monomethyl Hg in the sediments of the Venice Lagoon (Italy) were measured in June 2005 in order to identify the factors affecting the methylation of inorganic Hg. While the rates of Hg methylation and sulfate reduction were generally higher in the surface layers (0–2.5 cm), the correlation between Hg methylation and sulfate reduction rates was not significant when considering all depths and sites. This discrepancy is discussed considering two factors: the activity of sulfate-reducing bacteria and Hg solubility. The former factor is important in determining the Hg methylation rate in comparable geochemical conditions as evidenced by similar vertical profiles of Hg methylation and sulfate reduction rates in each sediment core. The latter factor was assessed by comparing the Hg methylation rate with the particle—water partition coefficient of Hg. The Hg methylation rates normalized to sulfate reduction rates showed a negative linear correlation with the logarithm of the particle-water partition coefficient of Hg, suggesting that the availability of dissolved Hg is a critical factor affecting Hg methylation. Solid FeS seems to play an important role in controlling the solubility of Hg in Venice Lagoon sediments, where sulfate and iron reductions are the dominant electron-accepting processes. Overall, the production of monomethyl Hg in the Venice Lagoon is controlled by a fine balance between microbial and geochemical processes with key factors being the microbial sulfate reduction rate and the availability of dissolved Hg.
Biodegradable chelating agent ethylenediaminedisuccinic acid reduces uptake of copper through alleviation of copper toxicity in hydroponically grown Chrysanthemum Coronarium L.
Authors: Wei Lan , Luo Chunling , Wang Chunchun , Li Xiangdong , Shen Zhenguo
Published: June 2007

Hydroponic cultures were conducted to investigate the effects of the biodegradable chelating agent S,S-ethylenediaminedisuccinic acid (EDDS) on the growth and copper uptake by garland chrysanthemum (Chrysanthemum coronarium L.), a plant species sensitive to soil chelate amendment. In the presence of 50 μmol/L Cu, the addition of EDDS increased shoot and root biomass and the vitality of cells in root tips and decreased the relative electrolyte leakage of root cells and the concentration of Cu in shoots. When the roots were pretreated with 65°C hot water for 0.5 to 2 h or with 0.001 to 0.1 mol/L HCl for 24 h before the exposure to 50 μmol/L Cu + 100 μmol/L EDDS, the concentration of Cu in shoots increased considerably compared with the plants without any pretreatment. A statistically significant correlation was found between the Cu concentrations in shoots and the relative electrolyte leakage of root cells. These results indicated that Cu—EDDS might be a less bioavailable form to plants and that some physiological damage to the roots led to enhanced accumulation of Cu in plant shoots.
Analysis of organotins in seawater of the Southern Ocean and Suruga Bay, Japan, by gas chromatography/inductively coupled plasma mass spectrometry
Authors: Kurihara Ryo , Rajendran Ramaswamy Babu , Tao Hiroaki , Yamamoto Itsuaki , Hashimoto Shinya
Published: June 2007

Organotins are widespread in the world's oceans and have a detrimental effect on organisms. However, there is little information on their distribution in the Southern hemisphere. We analyzed organotins in seawater from the Southern Ocean and Suruga Bay, Japan, using gas chromatography/inductively coupled plasma mass spectrometry. Organotins were compared in two contrasting environments—one in shallow, temperate coastal waters (Suruga Bay) and the other in cold, deep waters of the far Southern Ocean. Twelve kinds of organotins were detected from Suruga Bay, with tributyltin (0.184–13.6 ng Sn/L) and total organotins (0.801–19.7 ng Sn/L). In contrast, three kinds of organotins were detected in the Southern Ocean, with total organotins (from not detected to 0.266 ng Sn/L). The ratios of degraded products of tributyltin and triphenyltin from the Southern Ocean were higher than those in Suruga Bay, suggesting that fresh input of organotins into the Southern Ocean is relatively low. The presence of butyltins in Antarctic sediments and biota has been demonstrated previously; however, the present study is the first to describe trace levels of organotins in the Southern Ocean approximately 1,000 km from Antarctica.
Effects of methylmercury exposure on the immune function of juvenile common loons (Gavia immer)
Authors: Kenow Kevin P. , Grasman Keith A. , Hines Randy K. , Meyer Michael W. , Gendron-Fitzpatrick Annette , Spalding Marilyn G. , Gray Brian R.
Published: June 2007

We conducted a dose-response laboratory study to quantify the level of exposure to dietary Hg, delivered as methyl-mercury chloride (CH3HgCl), that is associated with suppressed immune function in captive-reared common loon (Gavia immer) chicks. We used the phytohemagglutinin (PHA) skin test to assess T-lymphocyte function and the sheep red blood cell (SRBC) hemagglutination test to measure antibody-mediated immunity. The PHA stimulation index among chicks receiving dietary Hg treatment did not differ significantly from those of chicks on the control diet (p = 0.15). Total antibody (immunoglobulin [Ig] M [primary antibody] + IgG [secondary response]) production to the SRBC antigen in chicks treated with dietary methylmercury (MeHg), however, was suppressed (p = 0.04) relative to chicks on control diets. Analysis indicated suppression of total Ig production (p = 0.025 with comparisonwise α level = 0.017) between control and 0.4 μg Hg/g wet food intake treatment groups. Furthermore, the control group exhibited a higher degree of variability in antibody response compared to the Hg groups, suggesting that in addition to reducing the mean response, Hg treatment reduced the normal variation attributable to other biological factors. We observed bursal lymphoid depletion in chicks receiving the 1.2 μg Hg/g treatment (p = 0.017) and a marginally significant effect (p = 0.025) in chicks receiving the 0.4 μg Hg/g diet. These findings suggest that common loon chick immune systems may be compromised at an ecologically relevant dietary exposure concentration (0.4 μg Hg/g wet wt food intake). We also found that chicks hatched from eggs collected from low-pH lakes exhibited higher levels of lymphoid depletion in bursa tissue relative to chicks hatched from eggs collected from neutral-pH lakes.
1H and 19F nuclear magnetic resonance microimaging of water and chemical distribution in soil columns
Authors: Simpson Myrna J. , Simpson André J. , Gross Dieter , Spraul Manfred , Kingery William L.
Published: June 2007

Nuclear magnetic resonance (NMR) microimaging is a noninvasive and nondestructive technique that has great potential for the study of soil processes. Hydrogen-1 NMR microimaging techniques were used to examine the distribution of water in four different soil cores. Fluorine-19 NMR microimaging is also used to study the transport of three model contaminants (hexafluorobenzene, sodium fluoride, and trifluralin) in soil columns. The 1H water distribution studies demonstrate that NMR microimaging can provide unique detail regarding the nature and location of water in soils. Image distortion (magnetic susceptibility) was observed for soil samples low in water (20–28% by weight) and that contained an iron content of 0.73 to 0.99%. Highly resolved images were obtained for the organic-rich soil (Croatan sample) and also facilitated the analysis of bound and unbound soil water through varying spin echo times. The contaminant studies with 19F NMR demonstrated that preferential flow processes can be observed in soil cores in as little as 16 h. Studies with hexafluorobenzene produced the highest quality images whereas the definition decreased over time with both trifluralin and sodium fluoride as the compounds penetrated the soil. Nonetheless, both 1H and 19F NMR microimaging techniques demonstrate great promise for studying soil processes.
Coupling contaminants with demography: Effects of lead and selenium in Pacific common eiders
Authors: Wilson Heather M. , Flint Paul L. , Powell Abby N.
Published: June 2007

We coupled intensive population monitoring with collection of blood samples from 383 nesting Pacific common eiders (Somateria mollisima v-nigrum) at two locations in Alaska (USA) from 2002 to 2004. We investigated annual, geographic, and within-season variation in blood concentrations of lead and selenium; compared exposure patterns with sympatrically nesting spectacled eiders (Somateria fischeri); and examined relationships with clutch size, egg viability, probability of hatching, and apparent survival of adult females. Lead concentrations were elevated in 3.6% of females, and all individuals exhibited elevated selenium, most (81%) at concentrations associated with death in captive waterfowl. Blood lead and selenium concentrations varied both within and among site-years and were lower than those of spectacled eiders. During incubation, blood lead concentrations in females increased significantly (possibly via re-release of stored lead from bone), whereas selenium concentrations decreased (likely because of natural excretion). Probability of a nest containing at least one nonviable egg was positively related to blood selenium in hens, but adverse effects in other life-history variables were not supported. Although reproduction appeared to be sensitive to selenium toxicity, our data suggest that high rates of nonviability are unlikely in this population and that selenium-related reductions to clutch size would be inconsequential at the scale of overall population dynamics. We conclude that Pacific common eiders and other wild marine birds likely have higher selenium tolerances than freshwater species and that interspecific differences in exposure levels may reflect differences in reproductive strategies.
A potential genomic biomarker for the detection of polycyclic aromatic hydrocarbon pollutants: Multidrug resistance gene 49 in Drosophila melanogaster
Authors: Vache Christel , Camares Olivier , Marie-Céleste  , Cardoso-Ferreira  , Dastugue Bernard , Creveaux Isabelle , Vaury Chantal , Bamdad Mahchid
Published: June 2007

Polycyclic aromatic hydrocarbons (PAHs) are a major source of air, water, and soil pollution. The multidrug resistance (mdr)/permeability glycoprotein (P-gp) complex is implicated in the multidrug resistance pattern developed against various drugs and xenobiotics, including polycyclic aromatic hydrocarbons. In order to develop a genomic biomarker, we investigated the response of the mdr49 gene (mdr49) of Drosophila melanogaster to PAHs. Structural analysis of mdr49-PA, which is the putative protein expressed from Drosophila mdr49gene, demonstrated that this transmembrane protein indeed belongs to the adenosine triphosphate-binding cassette transporter superfamily. Polymerase chain reaction (PCR) and real-time PCR analysis revealed that the mdr49 gene is expressed continuously at all the stages of fly development, including embryos, pupae, larvae, and adults, as well as in embryonic Drosophila S12 cells. In the adult fly, the mdr49 gene was expressed in all the analyzed segments (head, thorax, and abdomen) and organs (olfactory and sexual organs). The quantification of mdr49 transcripts by real-time PCR in adult flies exposed to benzo[a]pyrene over time or in presence of increasing concentrations of this pollutant showed a clear dose-dependent response. Similarly, mdr49 gene expression increased after adult flies were exposed to structurally varied PAHs. The detection of tested PAHs by Drosophila P-gp efflux pump was checked by flow cytometry.
Preceding Crop Affects Grain Cadmium and Zinc of Wheat Grown in Saline Soils of Central Iran
Authors: Khoshgoftarmanesh Amir H. , Chaney Rufus L.
Published: June 2007

Enhanced Cd concentrations in wheat (Triticum aestivumL.) grain produced on saline soils of central Iran have been recently reported. Because wheat bread is a major dietary component for the Iranian people, practical approaches to decrease Cd concentration in wheat grain were investigated. This study investigated the influence of sunflower–wheat vs. cotton–wheat rotations on extractable Cd and on Cd uptake by wheat in these salt‐affected soils. Two fields with different levels of Cd contamination (1.5 and 3.2 mg total Cd kg−1dry soil) were cropped with different rotations (cotton–wheat and sunflower–wheat) in Qom province, central Iran. Seeds of cotton (GossypiumL.) or sunflower (Helianthus annuusL. cv. Record) were planted in plots. After harvesting of the plants and removal of crop residues, wheat (cv. Rushan) was seeded in all plots. For both studied soils, the concentrations of Cd extracted by 0.04MEDTA and 1MCaCl2were significantly (P≤ 0.05) greater after cotton than after sunflower. Accordingly, the total amount of Cd in sunflower shoot was significantly (P≤ 0.05) greater than in the cotton shoot. Shoot Cd content in wheat plants grown after cotton and sunflower were significantly different; wheat shoots after cotton accumulated more Cd (two to four times) than after sunflower. Wheat grain Cd concentration after sunflower was much lower (more than seven times) than after cotton. The results of this study showed that sunflower in rotation with wheat in salt‐affected soils of central Iran significantly reduced the risk of Cd transfer to wheat grain.
Effects of GABAB receptor antagonists CGP63360, CGP76290A and CGP76291A on learning and memory processes in rodents
Authors: Getova Damianka , Dimitrova Darinka
Published: June 2007

Data in literature that use methods for studying the learning and memory processes suggest that GABA and especially GABAB receptor antagonists may be active against amnesia. The aim of our study was to examine the effects of three new GABAB-antagonists on learning and memory processes. Active and passive avoidance tests with negative reinforcement in rats were used. The rats treated with different GABAB receptor antagonists showed improving effects in both tests (active and passive avoidances)on learning as well as on memory retention. There are some differences in their activities, probably due to its chemical structures. The phosphinic analogue CGP63360A is potent to the point that the benzoic one CGP76290A and the left isomer of the benzoic analogue CGP76291A has no effect. It may be concluded that the obtained results on the GABAB receptor antagonists could contribute to their pharmacological characteristics and might be of interest for potential clinical implication.
Equine idiopathic cheek teeth fractures: Part 3: A hospital‐based survey of 68 referred horses (1999–2005)
Authors: DIXON P. M. , BARAKZAI S. Z. , COLLINS N. M. , YATES J.
Published: June 2007

Reasons for performing study: There is limited information available on the more serious sequellae of idiopathic cheek teeth (CT) fractures.

Objectives: To obtain information on clinical and ancillary diagnostic findings in referred horses with idiopathic CT fractures.

Methods: Details of all horses suffering from idiopathic CT fractures referred to the Equine Hospital at the University of Edinburgh 1999–2005 were examined, and information concerning fracture patterns, clinical and ancillary diagnostic findings, treatments and long‐term response to treatments were obtained and analysed.

Results: A total of 60 maxillary and 17 mandibular idiopathic CT fractures were diagnosed in 68 horses. Fracture patterns included maxillary CT lateral slab fractures (45%), maxillary CT midline sagittal fractures (16%) and various other patterns of maxillary CT fractures (17%). In the mandibular CT, lateral slab fractures were found (12%) and various other CT fracture patterns were present in 10%. The more centrally positioned CT (maxillary and mandibular Triadan 08s and 09) were preferentially fractured. Clinical signs included quidding in 47% of cases; bitting and behavioural problems (28%); signs of apical infection, including bony swellings and nasal discharge (21%); anorexia/weight loss (15%); halitosis (13%); and buccal food impaction (12%). The treatment of all cases was conservative whenever possible and included corrective rasping of the remaining tooth (46% of cases); oral extraction of the smaller and loose dental fragment (32%) and extraction of the entire fractured tooth by oral extraction (28%) or by repulsion (13%). Prophylactic treatment of adjacent, nonfractured CT with carious infundibula was possibly of value in preventing further midline sagittal maxillary CT fractures.

Conclusions: Horses referred with idiopathic CT fractures frequently have clinical signs of apical infection of the fractured CT and these teeth require extraction, orally if possible. More conservative treatment of idiopathic CT fractures without signs of gross apical infection can resolve clinical signs in most cases.

Potential relevance: In the absence of apical infection, extraction of only the loose dental fragments of CT with idiopathic fractures is usually successful.
The effects of disappointment on hindsight bias for real‐world outcomes
Authors: Pezzo Mark V. , Beckstead Jason. W.
Published: June 2007

Examined the effects of motivated processing on hindsight bias. One hundred fifty three college students estimated and later recalled the likelihood that 30 self‐relevant events would occur during the next 2 months. Multi‐level modelling was used to determine the (within‐subject) effects of expectations, event valence and event controllability on hindsight bias and the extent to which these effects were moderated by participants' need for cognition (NFC) scores (between‐subjects). For events that actually occurred, we found support for defensive processing in that the bias was smaller for negative events. Also, for events that actually occurred, those judged as more controllable produced a larger bias. Neither valence nor controllability had any effect on the size of the bias for events that did not occur. The size of the bias for occurrences did not differ significantly from that for non‐occurrences. Finally, NFC did not moderate the effects of valence or controllability, nor did it directly affect the size of the bias. Copyright © 2007 John Wiley & Sons, Ltd.
Comparative skeletal features between Homo floresiensis and patients with primary growth hormone insensitivity (Laron syndrome)
Authors: Hershkovitz Israel , Kornreich Liora , Laron Zvi
Published: June 2007

Comparison between the skeletal remains of Homo floresiensis and the auxological and roentgenological findings in a large Israeli cohort of patients with Laron Syndrome (LS, primary or classical GH insensitivity or resistance) revealed striking morphological similarities, including extremely small stature and reduced cranial volume. LS is an autosomal recessive disease caused by a molecular defect of the Growth Hormone (GH) receptor or in the post‐receptor cascades. Epidemiological studies have shown that LS occurs more often in consanguineous families and isolates, and it has been described in several countries in South East Asia. It is our conclusion that the findings from the island of Flores, which were attributed to a new species of the genus Homo, may in fact represent a local, highly inbred, Homo sapiens population in whom a mutation for the GH receptor had occurred. Am J Phys Anthropol, 2007. © 2007 Wiley‐Liss, Inc.
Play in adult bonobos (Pan paniscus): Modality and potential meaning
Authors: Palagi Elisabetta , Paoli Tommaso
Published: June 2007

The aim of this study was to thoroughly investigate social play and its modalities among adult bonobos. We evaluated how play intensity varies according to the sex‐class combination of the playmates and we also performed an analysis on social locomotor‐rotational movements (L‐R play) and contact interactions (C play). Rough and gentle play sessions were performed with comparable frequencies by male–female and female–female adult dyads, with play signals unlikely when the playmates strongly differed in age and in rank position. L‐R play rates did not differ according to the sex‐combination of the players; in contrast, C play sessions were particularly frequent among females. Play faces (play signals) were significantly higher during C play than L‐R play sessions, thus suggesting that playmates assess reciprocally yet safely their relationships by using facial displays to avoid any kind of misunderstanding. Play was positively correlated with grooming and contact sitting interactions, suggesting that it may be used as a social enhancer. Finally, we found no correlation between both play contexts (L‐R and C play) and age, size and rank differences of the players. In conclusion, we suggest that bonobos with their egalitarian society, peculiar social structure, and playful tendency represent an attractive testing subject to examine empirically many emerging hypotheses on adult play behavior. Am J Phys Anthropol, 2007. © 2007 Wiley‐Liss, Inc.
Temporal dynamics of nutrition, parasitism, and stress in colobus monkeys: Implications for population regulation and conservation
Authors: Chapman Colin A. , Saj Tania L. , Snaith Tamaini V.
Published: June 2007

The need to develop conservation plans calls for the ability to identify ecological factors that influence population density. Because stress is known to affect fecundity and mortality, increasing stress may provide a warning of potential population declines. We examined the effects of temporal variation in nutrition and parasitism on stress in endangered red colobus monkeys in Kibale National Park, Uganda. First, we tested the hypothesis that parasitism and nutrition would individually affect stress levels. We found that periods of poor‐quality diet corresponded with an increase in cortisol. Similarly, increases in parasite infections were associated with increased cortisol. Next, we predicted that a poor‐quality diet would facilitate increased parasite infections, and that together, they would lead to amplified stress. However, we found no support for such amplification, likely because the quality of the diet had little effect on parasite infections. Third, we tested whether individuals in a larger group were subject to food stress due to greater within‐group competition, which would intensify nutritional stress and parasitism, and lead to reduced reproduction. Although we found no evidence to support a group size effect on parasites, cortisol levels in the large group tended to be higher than those in the small group, and the large group had fewer infants per female. The results suggest that parasitism and poor nutrition lead to increased stress which, because they are known to be associated with reduced fecundity and increased mortality, may lead to population declines. Am J Phys Anthropol, 2007. © 2007 Wiley‐Liss, Inc.