bluuebunny/crossref_metadata_2025 huggingface dataset:
A Small Wind-Electric System Based on an Improved Version of the ITDG Axial Flux Permanent Magnet Generator
Authors: Probst Oliver , Gonzalez Adrián , Roidl Matthias , Llamas Armando
Published: January 2007

An improved axial-flux permanent-magnet (AFPM) generator has been built, as based on the ITDG/Piggott design for rural wind-electricity. The generator is characterized by electromechanical analysis, with parameters determined through curve fitting. The measured DC behaviour is explained by load-dependent rectifier transfer functions for voltage and current. Miscellaneous losses are parameterized in terms of a scaling law involving electrical load and shaft frequency. Two electrical configurations of the generator are characterized experimentally, i.e. (i) low-voltage star-parallel, and (ii) high-voltage star-series, with both ac and dc loads. Simulated system behaviour is determined by combining the electromechanical curves with the set of aerodynamic power curves obtained from modelling with blade element momentum theory. Using the blade geometry proposed by Piggott, the operational characteristics are satisfactory for charging 24 V batteries if the high-voltage configuration is used; i.e. no electronic load control is required. The complete wind system is an attractive low-cost method for remote wind-electric applications in low-speed (∼ 3 m/s) and medium-speed (∼ 5 m/s) wind sites.
Mechanical Characteristics of Some Deepwater Floater Designs for Offshore Wind Turbines
Authors: Chen Zhen-Zhe , Tarp-Johansen Niels Jacob , Jensen Jørgen Juncher
Published: January 2007

This paper presents an initial study of the mechanical characteristics of some deepwater floater designs for offshore wind turbines. Three different concepts (NREL TLP Dutch Tri-floater, and Japanese SPAR) are summarized, based on data from the available studies. A 5 MW Horizontal Axis Wind Turbine is used for the reference wind turbine and the steady wind load is calculated from the Blade Element Momentum method. These three concepts are simplified to 2D models and the static analyses of NREL TLP and Dutch Tri-floater are compared. The 2D NREL TLP model is selected for dynamic analysis, in which: (1) regular and irregular wave loads are calculated from the Morison equation for the relative motions in the time domain; (2) Airy's linear wave theory is applied to compute the wave kinematics; (3) The 10-minutes irregular waves are realized from the JONSWAP spectrum. For comparison, the same 2D NREL TLP floater model is also developed and implemented as a subsystem in the wind turbine simulation program, HAWC. The HAWC results are compared with those from our model.
The addition of anticipated regret to attitudinally based, goal‐directed models of information search behaviours under conditions of uncertainty and risk
Authors: Taylor Steven A.
Published: January 2007

Social science attempts to incorporate emotions into models of judgment and decision making have faced significant theoretical challenges, as well as produced conflicting empirical results. The following study first contributes to the body of knowledge by providing a theoretical explanation for the observed conflicting results from such models. In fact, both extant theory and the results reported herein suggest that a certain amount of variability in results should be expected from empirical investigations based on such models, particularly related to differences in respondents' level of affective versus cognitive involvement. Second, an argument is presented for considering a special case of Perugini and Bagozzi's (2001) Model of Goal‐directed Behaviours (MGBs) when investigating these issues using attitude‐based explanations of goal‐related behaviours. Specifically, empirical evidence is presented for broadening the MGB model by including anticipated regret as an explanatory variable independent of other anticipated emotions, and deepening the theory by calling for multidimensional conceptualizations of the attitude and perceived behavioural control constructs. The implications of the reported study are presented and discussed.
Outcomes of Dialysis Initiated During the Neonatal Period for Treatment of End-Stage Renal Disease: A North American Pediatric Renal Trials and Collaborative Studies Special Analysis
Authors: Carey William A. , Talley Lynya I. , Sehring Sally A. , Jaskula Janet M. , Mathias Robert S.
Published: January 2007

OBJECTIVE. We sought to determine the outcomes of initiating long-term dialysis of neonates and children aged >1 to 24 months with end-stage renal disease.

PATIENTS AND METHODS. By querying the North American Pediatric Renal Trials and Collaborative Studies database, we obtained information on 193 neonates (≤1 month of age) and 505 children (>1–24 months of age) with a presumptive diagnosis of end-stage renal disease who initiated long-term dialysis. Dialysis characteristics and likelihood of hospitalization were compared using the χ2 test, and duration of hospitalization was compared using the Wilcoxon 2-sample test. Product limit methods were implemented, and the log rank test was used to compare time-to-event analyses. Multivariate analyses were performed using Cox proportional hazards models.

RESULTS. Neonates with end-stage renal disease were more likely to receive peritoneal dialysis versus hemodialysis than older children with end-stage renal disease. Moreover, neonates who initiated dialysis during the first month of life were just as likely to terminate dialysis as were the older children. Rates of renal transplantation were significantly lower in the neonates compared with the older children, but neonates were more likely to recover function of the native kidney. Although neonates were more often hospitalized, their overall risk of mortality was similar to that observed in older children.

CONCLUSIONS. Neonates with a presumptive diagnosis of end-stage renal disease may initiate long-term dialysis during the first month of life with outcomes comparable to those of patients who initiate dialysis later in infancy.
Provocation of Neurocardiogenic Syncope During Head-up Tilt Testing in Children: Comparison Between Isoproterenol and Nitroglycerin
Authors: Vlahos Antonios P. , Tzoufi Meropi , Katsouras Christos S. , Barka Theodora , Sionti Irene , Michalis Lampros K. , Siamopoulou Antigoni , Kolettis Theofilos M.
Published: January 2007

OBJECTIVE. Although nitroglycerin- and isoproterenol-augmented tilt tests are of equal value in the diagnosis of neurocardiogenic syncope in adults, no data exist in children. We compared the sensitivity and specificity of the 2 tests in a pediatric population.

PATITENS AND METHODS. We studied 85 patients (33 boys; mean age: 11.6 ± 2.9 years). Of them, 56 had a diagnostic history of neurocardiogenic syncope, whereas 29 served as controls. After a negative passive phase, they were randomly assigned to either intravenous isoproterenol or sublingual nitroglycerin, and tilt was continued for 20 minutes.

RESULTS. Sensitivity was 0.78 for the isoproterenol test and 0.79 for the nitroglycerin test, but specificity was significantly higher for isoproterenol test compared with nitroglycerin test. In patients with a positive test, the duration of the recovery period was significantly longer after nitroglycerin (8.4 ± 2.7 minutes) than after isoproterenol (5.1 ± 1.6 minutes).

CONCLUSIONS. Nitroglycerin- and isoproterenol-augmented tilt tests are associated with equal sensitivity in the diagnosis of neurocardiogenic syncope in children and adolescents. However, nitroglycerin results in more false-positive tests and produces more prolonged vasovagal symptoms. Our data do not support the routine use of nitroglycerin in the evaluation of syncope in this age group.
The Size and Performance of Public Sector Activities in Europe: An Overview*
Authors: Handler Heinz , Koebel Bertrand , Reiss J. Philipp , Schratzenstaller Margit
Published: January 2007

Obvious
differences between countries regarding their economic performance have led to
the question whether the size, structure, and organisation of the public sector
contribute to cross-country income levels and growth gaps. Public sector
activities may have an effect on overall productivity and economic growth via
two channels: directly, through the level and changes of productivity within
the public sector, and indirectly, by triggering off productivity changes in
private production. This paper is concerned with the former aspect. It provides
an overview of recent empirical literature on public sector performance and
relates performance to the size and structure of the public sectors in Europe,
the US and Japan. The results are not fully conclusive, but seem to attribute
more efficiency to smaller rather than to larger government sectors. Public
sector reforms aiming to consolidate the size of government are likely to
enhance the sector's own productivity and are thereby prone to contribute
positively to overall economic performance.
Dollarisation and Plan: The Cuban Case
Authors: Virgili Teresa , Xalma Cristina
Published: January 2007

This paper
deals with the process of economic reform established by the Cuban government
after the disintegration of the Soviet Block. Therefore, the legalisation of
the possession and use of US dollar (1994-2004) will be specifically analysed,
as well as the measures to canalise US dollars in order to achieve strategic
economic recovery carefully planned to support - rather than to betray - Cuban
social revolution. Consequences of the application of these measures, such as
necessary changes in economic planning, economic and monetary duality, as well
as the operative function concerning planning and market in economic management
are also analysed. In addition, the paper also examines the de-dollarisation
process.
Prey Supply and Predator Demand in a Reservoir of the Southeastern United States
Authors: Raborn Scott W. , Miranda Leandro E. , Driscoll M. Todd
Published: January 2007

We estimated annual prey supply and predator demand distributions for the fish assemblage of Norris Reservoir, Tennessee, to assess potential prey deficiencies. Prey supply was defined as the surplus biomass that could be removed without affecting future prey generations and was limited to cohorts consumed by predators. Demand was represented by the annual consumption by the predator community (piscivorous fishes) and was estimated with bioenergetics models. Our demand estimates were conservative because predators may have greater demand for prey than what they actually consume. Together, clupeids (gizzard shad Dorosoma cepedianum, threadfin shad D. petenense, and alewife Alosa pseudoharengus) and Lepomis spp. accounted for 80% of overall prey fishes consumed. Median annual demand for clupeids and Lepomis spp. combined was 271 kg/ha (90% confidence interval = 183–552 kg/ha) from August 1996 to July 1997 and 182 kg/ha (92–509 kg/ha) from August 1997 to July 1998. Median supply during these times was 848 kg/ha (103–18,989 kg/ha) and 413 kg/ha (317–540 kg/ha). Dividing supply values by demand values yielded supply–demand ratio distributions with medians of 2.9:1 (0.3:1–67.5:1) and 2.3:1 (0.8:1–4.8:1) for the two periods. Using a historical area–density data set (coves sampled with rotenone; N = 22 years), we found the median annual supply to be 167 kg/ha (49–982 kg/ha), demand to be 109 kg/ha (51–239 kg/ha), and the supply–demand ratio to be 1.5:1 (0.4:1–10.4:1). Historical values of the supply–demand ratio were less than 1:1 (i.e., supply was insufficient to meet demand) 32% of the time. The latter estimate is minimal because the threshold supply–demand ratio (the ratio below which predators are forage limited) was probably greater than 1:1, as predators cannot capture all prey with 100% efficiency and our definition of demand was conservative. We suggest adjusting demand to equal the median historical supply.
Persistent Mortality of Brook Trout in Episodically Acidified Streams of the Southwestern Adirondack Mountains, New York
Authors: Baldigo Barry P. , Lawrence Gregory , Simonin Howard
Published: January 2007

Water chemistry, discharge, and mortality of caged brook trout Salvelinus fontinalis were characterized in six headwater streams in the southwestern Adirondack Mountains of New York during spring 2001–2003. Results were compared with mortality recorded during similar tests during 1984–1985, 1988–1990, and 1997 to assess contemporary relations between stream acidification and brook trout mortality, the effects of exposure duration on mortality, and the effects of decreased rates of acidic deposition on water quality and fish mortality. Water quality and mortality of caged, young‐of‐the‐year brook trout were evaluated during 30‐d exposure periods from mid‐April to late May during the most recent tests. In 2001–2003, mortality ranged from 0% to 100% and varied among streams and years, depending on the timing of toxicity tests in relation to the annual snowmelt and on the ability of each watershed to neutralize acids and prevent acutely toxic concentrations of inorganic monomeric aluminum (Alim) during high‐flow events. Mortality rates in 2001–2003 tests were highly variable but similar to those observed during earlier tests. This similarity suggests that stream water quality in the southwestern Adirondack Mountains has not changed appreciably over the past 20 years. Concentrations of Alim greater than 2.0 and 4.0 μmol/L were closely correlated with low and high mortality rates, respectively, and accounted for 83% of the variation in mortality. Two to four days of exposure to Alim concentrations greater than 4.0 μmol/L resulted in 50–100% mortality. The extended periods (as long as 6 months) during which Alim concentrations exceeded 2.0 and 4.0 μmol/L in one or more streams, combined with the low tolerance of many other fish species to acid and elevated Alim concentrations, indicate a high potential for damage to fish communities in these and other poorly buffered streams of the Northeast.
Intercept Telemetry of the Hudson River Striped Bass Resident Contingent: Migration and Homing Patterns
Authors: Wingate Rebecca L. , Secor David H.
Published: January 2007

Hudson River striped bass Morone saxatilis show highly variable migration patterns, as observed through past tagging studies and otolith microchemical analyses. Recent studies have shown resident, estuarine, and ocean migratory contingents in the Hudson River. We undertook a directed study to more precisely characterize the seasonal migrations of the resident contingent. Remote biotelemetry was conducted on 12 resident striped bass during a 14‐month period in 2004–2005. All tagged striped bass migrated downriver from October 2004 to January 2005 and returned upriver from March to May 2005. Observed seasonal migration patterns were similar to those expected from previous tagging and otolith microchemistry studies: Directed downriver emigration to brackish‐water overwintering habitats was followed by upriver migration to spring–summer freshwater feeding and spawning habitats. Eight of 12 fish showed directed spring migrations upriver to their original tagging site and were repeatedly located there, indicating strong homing behavior and residence. These very specific patterns of homing indicate that local‐scale effects (e.g., fishing, pollution) can have persistent effects on components of the Hudson River striped bass population.
Heavy metal contamination status of Japanese cranes (Grus japonensis) in east Hokkaido, Japan-extensive mercury pollution
Authors: Teraoka Hiroki , Kumagai Yoshihiro , Iwai Hisae , Haraguchi Kensaku , Ohba Takashi , Nakai Kunihiko , Satoh Hiroshi , Sakamoto Mineshi , Momose Kunikazu , Masatomi Hiroyuki , Hiraga Takeo
Published: January 2007

—Japanese cranes (Grus japonensis) of eastern Hokkaido, Japan, and migrants between the Amur River basin and the eastern China—Korea Peninsula, live around fresh and brackish wetlands. Only a few thousand cranes are confirmed to exist in the world, so they are under threat of extinction. To understand the adverse effects of metal accumulation, we measured concentrations of three heavy metals in the liver, kidney, and muscle of 93 Japanese cranes from Hokkaido. The cranes were classified into six categories according to their sex and three life stages. Cadmium and mercury (Hg: total mercury) showed age-dependent but not sex-dependent accumulation in the liver and kidney. Twenty cranes showed 30 μg/g or higher levels of Hg in dry tissue and five adult cranes had more than 100 μg/g in their livers or kidneys. Cadmium concentrations were generally lower in all samples. Two adult cranes showed extremely high lead levels of more than 30 μg/g in their livers, suggesting lead poisoning. These results have highlighted the widespread and high levels of Hg pollution in Japanese cranes in Hokkaido, Japan.
Agricultural intensity and landscape structure: Influences on the macroinvertebrate assemblages of small streams in northern Germany
Authors: Schriever Carola A. , Ball Maria Hansler , Holmes Chris , Maund Steve , Liess Matthias
Published: January 2007

—The present study aimed to relate aquatic macroinvertebrate community composition to agricultural intensity and landscape structure. A total of 360 streams were investigated within the Aller river basin in northern Germany. The study area is typical of central German arable agricultural regions, but the small streams were of low dilution potential. These streams were characterized for abiotic parameters (including modeled potential for diffuse inputs from agricultural sources) and macroinvertebrate communities, with data collected over a 17-year period. Spray drift potential did not correlate with community composition. In contrast, the relative index of runoff potential (RP) was negatively correlated with various measures of taxonomic richness and abundance. Community composition also was correlated with environmental parameters, including stream width, clay content of sediment, and presence of dead wood in sediment. The abundance of sensitive species decreased significantly during the main period of agrochemical use at sites of high RP but completely recovered by the following spring. Long-term decreased taxonomic richness and a shift to ecologically robust species also were observed at sites of high RP. The results suggest that long-term alterations in community measures probably were associated with factors related to runoff input. Nevertheless, the community composition remained reasonably rich and even. Landscape structure also appeared to influence community structure. Abundance of sensitive species remained significantly enhanced, even at sites of high RP, when forested reaches were present in upstream reaches. These probably provided a source of organisms for downstream recolonization and amelioration of effects at high RP.
Comparison of the estrogenic activities of seawater extracts from Suruga Bay, Japan, based on chemical analysis or bioassay
Authors: Hashimoto Shinya , Ueda Yasuhiro , Kurihara Ryo , Shiraishi Fujio
Published: January 2007

—The present study compared estrogenicity measured by in vitro bioassay and estrogenicity estimated by the chemical analysis of seawater from Suruga Bay, Japan. Nonylphenol, bisphenol A, estrone, 17β-estradiol, nonhydroxy polycyclic aromatic hydrocarbons, and hydroxy polycyclic aromatic hydrocarbons, some of which show estrogenic activity, were selected as the target compounds. The yeast two-hybrid system was used to evaluate the estrogenic activities of seawater and chemicals with or without rat liver S9. Concentrations of estrogenic compounds in seawater were measured by chemical analysis using gas chromatography/mass spectrometry. The main estrogenic compounds in seawater were estrone (≥9.2 ng/L), bisphenol A (≥l,070 ng/L), and nonylphenol (≥276 ng/L). The highest estrogenic activities in seawater were observed near a sewage treatment plant, but the predicted potencies based on the chemistry data were higher than those observed experimentally for the estrogenic activity in seawater. The estrogenicity measured by bioassay was raised considerably after S9 treatment; this observation was limited to the zone of freshwater immediately adjacent to the wastewater outfall.
Bioaccumulation and biotransformation of 61 polychlorinated biphenyl and four polybrominated diphenyl ether congeners in juvenile American kestrels (Falco sparverius)
Authors: Drouillard Ken G. , Fernie Kimberly J. , Letcher Robert J. , Shutt Laird J. , Whitehead Megan , Gebink Wouter , Bird David M.
Published: January 2007

—This study examined the bioaccumulation and dietary retention of 61 polychlorinated biphenyl (PCB) and four polybrominated diphenyl ether (PBDE) congeners in juvenile American kestrels (Falco sparverius). American kestrels were exposed to contaminants via egg injection and daily gavage dosing over the posthatch-to-fledgling period. Retention factors for PCBs were dependent on chemical hydrophobicity and chlorine substitution patterns and ranged from less than 1 to 16.4% for PCBs having vicinal hydrogen substitutions at meta-, para- carbons on at least one of the phenyl rings and between 13.2 and 81.5% for congeners containing chlorine substitutions at 4,4′-, 3′,4,5′-, 3,4′,5-, or 3,3′,5,5′- positions. These results indicate that juveniles are capable of biotransforming PCBs according to the same structure-activity rules as adults. A toxicokinetic model, initially parameterized using adult toxicokinetic parameters, was used to describe concentration trends in juveniles overtime. The adult model overestimated PCB concentrations but provided an adequate fit when elimination rate constants were increased by a factor of 12.7. Retention factors for the PBDE congeners 2,2′,4,4′-tetrabromodiphenyl ether (BDE 47), 2,2′,4,4′,6-pentabromodiphenyl ether (BDE 100), 2,2′,4,4′,5-pentabromodiphenyl ether (BDE 99), and 2,2′,4,4′,5,5′-hexabromodiphenyl ether (BDE 153) were from 7.8 to 45.3% of the total dose. The retention of BDE 47 was similar that observed for readily cleared PCBs, whereas the remaining PBDEs exhibited retention factors consistent with those of persistent PCBs. Half-lives for PBDEs in juveniles were estimated to range from 5.6 to 44.7 d. Assuming differences in PBDE toxicokinetics between juveniles and adults similar to those measured for PCBs, adult American kestrel PBDE half-lives are expected to range from 72 to 572 d.
Environmental estrogens suppress hormones, behavior, and reproductive fitness in male fathead minnows
Authors: Martinović Dalma , Hogarth William T. , Jones Rachel E. , Sorensen Peter W.
Published: January 2007

—This study explored the possibility that environmental estrogens in sewage effluent may reduce the reproductive fitness of adult male fish by suppressing their reproductive behaviors, including their ability to compete for nests and females. Male fathead minnows (Pimephales promelas) were exposed for three weeks to either blank control, effluent released by a sewage treatment plant (STPE), waterborne estradiol (E2), or a synthetic androgen (methyltestosterone [MT]). Afterward, fish were placed with females and a nest, and their behavior was monitored for 5 d in either the presence or the absence of a competing (unexposed control) male. Males exposed to either the STPE or E2 (∼50 ng/L, a level chosen to mimic the estrogenic content of the STPE) had elevated levels of circulating vitellogenin (p < 0.05) and lower levels of 11-ketotestosterone (KT; p < 0.05). Nearly all STPE-and E2-exposed males spawned successfully in the absence of a competing male, but in both cases, exposed males suffered nearly total reproductive failure when they had to compete. Conversely, males exposed to MT (∼50 ng/L) outcompeted control males. Behavioral observations suggested that subtle differences in agonistic behaviors, typically associated with circulating androgens (i.e., KT), were responsible. We speculate that male fish exposed to estrogenic effluent in the field are less likely to reproduce successfully within large populations of wild fish, thereby causing abnormal and potentially detrimental patterns of gene flow within those populations.
Nontarget deposition and losses of oxamyl in surface runoff from flatwoods citrus production areas
Authors: Wilson Patrick Chris , Boman Brian , Foos Jane Ferguson
Published: January 2007

—Pesticide export from citrus production areas is a concern in the Indian River Lagoon drainage basin (Florida, USA). These studies evaluated nontarget deposition and losses of the insecticide oxamyl from typical flatwoods citrus production areas in South Florida. Deposition was estimated with the use of Teflon® spray targets placed across nontarget water furrows during spray applications. After oxamyl applications, surface water runoff events were generated with an overhead irrigation system to simulate relatively low intensity rainfall. Results indicated that 0.3 to 20.0% of the applied active ingredient landed on nontarget water furrow surfaces and that the majority of oxamyl loss occurs in runoff events shortly following application. Mean concentrations were greater during the first runoff events, ranging from 34.7 to 47.0 μg/L. Total losses during the first several hours of each set of runoff events ranged from 0.1 to 3.8% of the total active ingredient applied. Similar losses can be expected when rainfall occurs shortly after application for other pesticides with similar chemical properties and application methods.
Enantiomeric composition of chiral polychlorinated biphenyl atropisomers in dated sediment cores
Authors: Wong Charles S. , Pakdeesusuk Usarat , Morrissey Joshua A. , Lee Cindy M. , Coates John T. , Garrison Arthur W. , Mabury Scott A. , Marvin Christopher H. , Muir Derek C. G.
Published: January 2007

—Enantiomer fractions (EFs) of seven chiral poly chlorinated biphenyls (PCBs) were measured in dated sediment cores of Lake Hartwell (SC, USA) and Lake Ontario (USA) to detect, quantify, and gain insight regarding microbial reductive dechlorination of PCBs in lake sediments with high and low concentrations, respectively. Lake Hartwell sediments had high total PCBs (5–60 μg/g), with significantly nonracemic EFs that generally were consistent with those from previous laboratory microcosm reductive dechlorination experiments using sediments from these sites. Thus, stereoselective reductive dechlorination had occurred in situ, including at total PCB concentrations of less than the threshold of approximately 30 to 80 μg/g suggested as being necessary for reductive dechlorination. Enantiomer fractions of PCBs 91, 95, 132, and 136 in Lake Hartwell cores were significantly correlated both with concentrations of those individual congeners and with total PCB concentration for some sites. This result indicates that enantioselective microbial dechlorination activity increases with higher concentrations within sediments for these congeners. Enantiomer composition reversed with depth for PCBs 91, 132, and 176, suggesting that multiple microbial populations may be present within the same core that are enantioselectively dechlorinating PCBs. Such observations indicate that concentration and time are not the only factors affecting biotransformation, complicating prediction of enantioselectivity. Comparison of EFs with dates suggested biotransformation half-lives of approximately 30 years, which is on the same time scale as sequestration by burial. In contrast, Lake Ontario sediments (maximum total PCBs, 400 ng/g) had racemic or near-racemic amounts of most congeners throughout the core profile, which is consistent with achiral indicators suggesting no microbial biotransformation within Lake Ontario sediments. Thresholds for reductive dechlorination may exist, but they would be at concentrations of less than 30 to 80 μg/g.
Metal uptake by Lolium perenne in contaminated soils using a four-step approach
Authors: Kalis Erwin J. J. , Temminghoff Erwin J. M. , Visser Anneloes , van Riemsdijk Willem H.
Published: January 2007

—Most research dealing with soil (solution) speciation and metal uptake by plants has focused on the relationships between a certain bioavailable fraction in the soil and metal uptake by aboveground parts of the plants. Here, a new approach to interpretation of metal uptake is presented that considers four steps: First, the metal concentration in the soil solution is related to the total metal content of the soil. Second, the metal adsorption to the root surface is related to the metal concentration in the soil solution. Third, the metal content in the roots is related to the adsorption of metal ions to the root surface. Fourth, the metal content in the shoots is related to the metal content in the roots. For grass grown on 10 different soils, it is shown that the metal adsorption to the root surface is pH-dependently related to the free or total metal concentration in the soil solution. The metal content in the roots depends linearly on the metal adsorption at the root surface, whereas the metal content in the shoots depends on the metal content in the roots, either linearly (Zn) or reaching a maximum (Cu, Pb, and Cd). For the Ni content in the shoots as a function of the root content, the relation is pH dependent, probably because of the competition effects of Ca. The pH of the soil has to be taken into account when CaCl2 extractions are used as a basis for risk assessment toward plants.
Effects of copper on sulfate reduction in bacterial consortia enriched from metal-contaminated and uncontaminated sediments
Authors: Jin Song , Drever James I. , Colberg Patricia J. S.
Published: January 2007

—The effects of copper amendments on bacterial sulfate reduction in enrichment cultures obtained from two types of freshwater sediment were examined. Sulfate-reducing bacterial (SRB) consortia were enriched from pond sediment with no known history of metal contamination (uncontaminated) and from reservoir sediment with a well-documented history of metal contamination (metal-contaminated). The rates and extent of sulfate reduction in each sediment type in the absence of added copper were indistinguishable. With amendments of 0.8 mg/L copper, no inhibitory effects on sulfate reduction were observed in either consortium type. At 8.0 mg/L copper, activity in uncontaminated SRB consortia was significantly inhibited, as evidenced by a delay in and decreased rate of sulfate reduction; sulfidogenesis in metal-contaminated consortia was apparently unaffected. When the dissolved copper concentration was 30.0 mg/L, sulfidogenic activity in pond sediment consortia was completely inhibited. The rate of sulfate reduction temporarily decreased in the metal-contaminated enrichments but recovered after a short time. In active microcosms, copper was precipitated as CuS. The results of this study suggest that SRB from metal-contaminated environments have a markedly higher metal tolerance than those enriched from uncontaminated environments. The most significant inference from this work is that metal sulfide formation alone does not explain observed differences in metal tolerance between SRB consortia enriched from uncontaminated sediments and those that are derived from metal-contaminated sediments.
Combined use of biomarkers and in situ bioassays inDaphnia magnato monitor environmental hazards of pesticides in the field
Authors: Barata Carlos , Damasio Joana , López Miguel Angel , Kuster Marina , de Alda María López , Barceló Damià , Riva Mari Carmen , Raldúa Demetrio
Published: January 2007

The aim of this investigation was to evaluate toxicity effects of pesticides in aquatic invertebrates using in situ bioassays with the local species, Daphnia magna. Investigations were carried out in the Delta del Ebro (northeast Spain) during the main growing season of rice (May-August). Measures of energy consumption (i.e., algal grazing) and of specific biochemical responses (biomarkers) were conducted in individuals transplanted at four stations, including a clean site upstream of the affected area and the three main channels that collect and drain the water from the rice fields into the sea. Seventeen pesticides were analyzed in water by on-line solid-phase extraction-liquid chromatography-tandem mass spectrometry. The results obtained indicated high levels of pesticides in water, with peak values of 487 μg/L for bentazone, 8 μg/L for methyl-4-chlorophenoxyacetic acid, 5 μg/L for propanil, 0.8 μg/L for molinate, and 0.7 μg/L for fenitrothion. Measured biological responses denoted severe effects on grazing rates; a strong inhibition of cholinesterases and carboxylesterases, which are specific biomarkers of organophosphorous and carbamate pesticides; and altered patterns of the antioxidant enzyme catalase and the phase II metabolizing enzyme glutathione S-transferase. Correlation analysis with pesticide residue levels converted to toxic units relative to its acute 48-h median lethal concentration of D. magna indicated significant and negative coefficients between the dominant pesticide residues and the observed biological response, thus denoting a clear cause-and-effect relationship. The results emphasize the importance of considering specific (biomarkers) as well as more generalized and ecologically related (grazing) in situ responses to identify and evaluate biological effects of environmental contaminants in the field.
Quantification and associated variability of induced vitellogenin gene transcripts in fathead minnow (Pimephales promelas) by quantitative real-time polymerase chain reaction assay
Authors: Biales Adam D. , Bencic David C. , Flick Robert W. , Lazorchak Jim , Lattier David L.
Published: January 2007

—Ecological risk assessors have a growing need for sensitive and rapid indicators of environmental exposures in aquatic ecosystems resulting from natural and synthetic estrogen-like compounds. Investigators developing subcellular exposure markers in traditional sentinel organisms must be vigilant about inherent variability of analyses, especially regarding regulatory and policy statements. Here, we report a quantitative real-time polymerase chain reaction (QPCR) assay for the detection of vitellogenin transcripts environmentally triggered in fathead minnows (Pimephales promelas). We demonstrate that our QPCR assay exhibits little inter- or intra-assay variability (21.7 and 11.9%, respectively). This method appears to be robust in terms of variability stemming from extrinsic sources, indicating that it may be readily transferable to laboratories having the requisite equipment. Our primary focus in development of this method derived from the observation that transcriptional responses of the vitellogenin gene (vtg) in fathead minnows demonstrated high biological variability between identically treated individuals, even under controlled laboratory conditions (coefficient of variation, > 100%). This variability was not seen in other genes from the same RNA preparations that we examined, suggesting that it is specific to the vitellogenin response. Our data and those of others suggest that variability in vtg expression is common to a number of aquatic vertebrates, which is indicative of genetic causation. Despite a relatively high degree of variability in vtg transcription, this method is sensitive enough to detect exposures of 5.0 ng 17α-ethinylestradiol (EE2)/L within 24 h of exposure, and it has the ability to discriminate 10.0 and 5.0 ng EE2/L within 48 h. The vitellogenin QPCR assay is a highly sensitive, comparatively rapid, and inexpensive method for the detection and characterization of exposure to environmental estrogens and estrogen mimics.
Mineralization and plant uptake of 14C-labeled nonylphenol, nonylphenol tetraethoxylate, and nonylphenol nonylethoxylate in biosolids/soil systems planted with crested wheatgrass
Authors: Dettenmaier Erik , Doucette William J.
Published: January 2007

—Microcosm experiments (duration, 150 d) were conducted to evaluate the mineralization and plant uptake of [14C]nonylphenol (NP), [14C]nonylphenol tetraethoxylate (NPE4), and [14C]nonylphenol nonylethoxylate (NPE9) in a soil/biosolids (99.5:0.5 w/w) environment planted with crested wheatgrass (Agropyron cristatum). Three initial nominal concentrations (6, 24, and 47 mg/kg dry wt) each of NP, NPE4, and NPE9 were examined along with unplanted and unplanted poisoned controls. Phenol (22 mg/kg) also was evaluated as a more degradable reference compound. The biosolids were obtained from a municipal treatment plant, and the loamy sand soil was freshly collected. Mineralization ranged from 7% for NP to 53% for phenol, and no enhancement was observed in the planted systems. For NP, NPE4, and NPE9, 14C foliar tissues concentrations were proportional to exposure concentrations but were 10-fold lower than the root concentrations and two- to threefold lower than the soil concentrations. Bioconcentration factors (BCFs) based on 14C measurements ranged from 0.31 (mg compound/kg dry plant/ mg compound/kg dry soil) for systems spiked with NP to 0.52 for systems spiked with NPE9. Results of the NP analysis (initial concentration, 47 mg/kg) showed a 90% decrease in the soil concentration and an average BCF of 1.0. The lower BCF calculated from the 14C analysis likely resulted from the presence of NP transformation products in the soil that are less available or are translocated by the plants but quantified by the combustion/liquid scintillation counting procedure.
Synergism between the toxicity of chlorophenols and iron complexes
Authors: Levy Smadar , Shechtman Svetlana , Zhu Ben-Zhan , Stadtman Earl R. , Stadler Richard , Chevion Mordechai
Published: January 2007

—Synergistic interactions could prove to be relevant when evaluating the toxicity of environmental pollutants in a complex mixture, especially when organic and inorganic substances co-occur at concentrations currently considered to be low-toxic or sublethal. Escherichia coli cells (SR-9 strain) were used as a model system for studying the cellular toxicity of environmental pollutants. Exposure of bacterial cells to a combination of pentachlorophenol (PCP) and a positively charged complex of iron or copper caused a dramatic inhibition of growth and an increase in cell death. Incubation of bacterial cells with PCP and either ferric-1,10-phenanthroline complex [Fe3+(OP)3]3+ (500 and 5 μM, respectively) or cupric-1,10-phenanthroline complex [Cu2+(OP)2]2+ (400 and 0.05 μM, respectively) showed two and four log units of cell death, respectively, in 30 min. In contrast, only minor amounts of cell death were observed with each component alone. Similar effects have been shown for other positively charged complexes of transition metals and for other biocides. The observed synergism was associated with the formation of novel noncharged and lipophilic ternary complexes, which contain PCP anions (or other polychlorinated anions) and the iron (or copper) complex. The ternary complexes demonstrated effective transport of their components into the cells.
Using an internal standard method to determine Henry's law constants
Authors: Ji Chang , Evans Emily M.
Published: January 2007

—An internal standard method is developed for the measurement of thermodynamic Henry's law constants (H). In this method, a mixture of the analytes and an internal standard is prepared and used to make a standard solution (organic solvent) and a dilute aqueous solution. Both the standard solution and the headspace samples above the aqueous solution at partitioning equilibrium in closed containers are subject to gas chromatographic (GC) analysis. Subsequently, the values of H for the analytes can be calculated from the known H of the internal standard and the GC peak-area ratios. Only approximate values of the concentrations of the compounds, the GC injection volumes, and the vapor-phase to liquid-phase volume ratios in the closed containers are needed in this approach. The method works particularly well for compounds that are highly soluble in water or that have low vapor pressures. Experimentally determined values of H are reported for some low-molecular-weight aldehydes, ketones, and nitriles, and their temperature dependencies are examined. The results also are compared with literature values. The applicability of this new approach is limited to compounds that have dimensionless H on the the order of 10−3 or less.
Mitochondrial control region variation in bank voles (Clethrionomys glareolus) is not related to Chernobyl radiation exposure
Authors: Meeks Heather N. , Wickliffe Jeffrey K. , Hoofer Steven R. , Chesser Ronald K. , Rodgers Brenda E. , Baker Robert J.
Published: January 2007

—Three previous studies at Chernobyl, Ukraine, documented elevated mitochondrial DNA diversity in bank voles (Clethrionomys glareolus) from radioactively contaminated sites. Little evidence was found to link patterns of diversity in contaminated areas to radiation exposure, but the experimental design precluded discriminating among alternative explanations for elevated diversity in exposed groups. Reference sites selected for the studies were relatively distant from contaminated sites and, additionally, were separated from contaminated sites by large river systems; thus, we hypothesized that differences among sites were correlated with geographic isolation rather than with radiation exposure. For the present study, we added three reference sites, which were selected based on minimal radioactive contamination, proximity to contaminated sites, and absence of obvious barriers to dispersal. We hypothesized that neighboring reference sites should exhibit levels and patterns of diversity similar to those of contaminated sites if the previously detected differences were, in fact, caused by geographic isolation. Indeed, levels of diversity in nearby reference sites are comparable to levels in contaminated sites. Additionally, nearby reference sites contain several haplotypes not observed at other study sites. Our results suggest that levels of diversity in contaminated regions are more plausibly explained by ecological and historical factors than by increased mutational pressure resulting from exposure to Chernobyl radiation.
Use of anti-coronavirus antibody testing of cerebrospinal fluid for diagnosis of feline infectious peritonitis involving the central nervous system in cats
Authors: Boettcher Irene C. , Steinberg Tanja , Matiasek Kaspar , Greene Craig E. , Hartmann Katrin , Fischer Andrea
Published: January 2007

Objective—To assess the use of measuring anti-coronavirus IgG in CSF for the diagnosis of feline infectious peritonitis (FIP) involving the CNS in cats.

Design—Prospective study.

Sample Population—CSF and serum samples from 67 cats.

Procedures—CSF and serum samples were allocated into 4 groups: cats with FIP involving the CNS (n = 10), cats with FIP not involving the CNS (13), cats with CNS disorders caused by diseases other than FIP (29), and cats with diseases other than FIP and not involving the CNS (15). Cerebrospinal fluid was evaluated for concentrations of erythrocytes, leukocytes, and total protein. Anti-coronavirus IgG was measured in CSF and serum by indirect immunofluorescence assay.

Results—CSF IgG (range of titers, 1:32 to 1:4,096) was detected in 12 cats, including 6 cats with neurologic manifestation of FIP, 4 cats with FIP not involving the CNS, and 2 cats with brain tumors. Cerebrospinal fluid IgG was detected only in cats with correspondingly high serum IgG titers (range, 1:4,096 to 1:16,384) and was positively correlated with serum IgG titers (r = 0.652; P < 0.01), but not with any other CSF parameter. Blood contamination of CSF resulted in ≤ 333 erythrocytes/μL in cats with CSF IgG.

Conclusions and Clinical Relevance—The correlation between serum and CSF IgG and the fact that CSF IgG was detected only in strongly seropositive cats suggested that CSF anti-coronavirus IgG was derived from blood. Measurement of anti-coronavirus IgG in CSF was of equivocal clinical use.
Long-term outcome of juvenile pubic symphysiodesis and triple pelvic osteotomy in dogs with hip dysplasia
Authors: Manley Paul A. , Adams William M. , Danielson Kelson C. , Dueland R. Tass , Linn Kathleen A.
Published: January 2007

Objective—To compare long-term outcomes of juvenile pubic symphysiodesis (JPS) and triple pelvic osteotomy (TPO) in dogs with hip dysplasia.

Design—Prospective clinical trial.

Animals—18 dogs with hip dysplasia (ie, distraction index ≥ 0.5 in at least 1 hip joint and no, mild, or moderate radiographic evidence of degenerative joint disease [DJD]).

Procedures—Dogs between 4 and 5.5 months old at enrollment were assigned to undergo JPS, and dogs between 5 and 12 months old were assigned to undergo TPO. All dogs were reexamined at 2 years of age.

Results—At 2 years of age, there were no significant differences between groups in regard to lameness scores, angle of extension of the hip joints, distraction index, peak vertical force, acetabular angle, radiographic DJD score, or owner-assigned scores of clinical function. Dorsal acetabular rim angle was significantly higher in dogs that underwent JPS than in dogs that underwent TPO. For dogs that underwent TPO, dorsal acetabular rim angle was significantly decreased and acetabular angle was significantly increased at 2 years of age, compared with values obtained prior to surgery.

Conclusions and Clinical Relevance—Results suggest that JPS and TPO have similar effects on hip joint conformation in dogs with moderate to severe hip dysplasia but that neither procedure eliminates the hip joint laxity characteristic of hip dysplasia or the progression of degenerative changes.
Comparison of core needle biopsy and fine-needle aspiration of enlarged peripheral lymph nodes for antemortem diagnosis of enzootic bovine lymphosarcoma in cattle
Authors: Washburn Kevin E. , Streeter Robert N. , Lehenbauer Terry W. , Snider Timothy A. , Rezabek Grant B. , Ritchey Jerry W. , Meinkoth James H. , Allison Robin W. , Rizzi Theresa E. , Boileau Melanie J.
Published: January 2007

Objective—To determine whether antemortem core needle biopsy and fine-needle aspiration of enlarged peripheral lymph nodes could be used to distinguish between inflammation and lymphosarcoma in cattle.

Design—Prospective study.

Animals—25 cattle with enlarged peripheral lymph nodes.

Procedures—Antemortem biopsies of the selected lymph nodes were performed with an 18-gauge, 12-cm core needle biopsy instrument. Fine-needle aspirates were performed with a 20-gauge, 4-cm needle. Specimens were analyzed by pathologists who were unaware of clinical findings and final necropsy findings, and specimens were categorized as reactive, neoplastic, or nondiagnostic for comparison with necropsy results.

Results—Sensitivity and specificity of core needle biopsy ranged from 38% to 67% and from 80% to 25%, respectively. Sensitivity of fine-needle aspiration ranged from 41% to 53%, and specificity was 100%. Predictive values for positive test results ranged from 77% to 89% for core needle biopsy and were 100% for fine-needle aspiration. Predictive values for negative test results were low for both core needle biopsy and fine-needle aspiration.

Conclusions and Clinical Relevance—Results indicated that core needle biopsy and fineneedle aspiration can aid in the antemortem diagnosis of bovine enzootic lymphosarcoma. Results of fine-needle aspiration of enlarged peripheral lymph nodes were more specific and more predictive for a positive test result than were results of core needle biopsy.