bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diffusion Tensor Imaging of Frontal White Matter and Executive Functioning in Cocaine-Exposed Children
Authors: Warner Tamara Duckworth , Behnke Marylou , Eyler Fonda Davis , Padgett Kyle , Leonard Christiana , Hou Wei , Garvan Cynthia Wilson , Schmalfuss Ilona M. , Blackband Stephen J. 
Published: November 2006

BACKGROUND. Although animal studies have demonstrated frontal white matter and behavioral changes resulting from prenatal cocaine exposure, no human studies have associated neuropsychological deficits in attention and inhibition with brain structure. We used diffusion tensor imaging to investigate frontal white matter integrity and executive functioning in cocaine-exposed children.
METHODS. Six direction diffusion tensor images were acquired using a Siemens 3T scanner with a spin-echo echo-planar imaging pulse sequence on right-handed cocaine-exposed (n = 28) and sociodemographically similar non-exposed children (n = 25; mean age: 10.6 years) drawn from a prospective, longitudinal study. Average diffusion and fractional anisotropy were measured in the left and right frontal callosal and frontal projection fibers. Executive functioning was assessed using two well-validated neuropsychological tests (Stroop color-word test and Trail Making Test).
RESULTS. Cocaine-exposed children showed significantly higher average diffusion in the left frontal callosal and right frontal projection fibers. Cocaine-exposed children were also significantly slower on a visual-motor set-shifting task with a trend toward lower scores on a verbal inhibition task. Controlling for gender and intelligence, average diffusion in the left frontal callosal fibers was related to prenatal exposure to alcohol and marijuana and an interaction between cocaine and marijuana exposure. Performance on the visual-motor set-shifting task was related to prenatal cocaine exposure and an interaction between cocaine and tobacco exposure. Significant correlations were found between test performance and fractional anisotropy in areas of the frontal white matter.
CONCLUSIONS. Prenatal cocaine exposure, alone and in combination with exposure to other drugs, is associated with slightly poorer executive functioning and subtle microstructural changes suggesting less mature development of frontal white matter pathways. The relative contribution of postnatal environmental factors, including characteristics of the caregiving environment and stressors associated with poverty and out-of-home placement, on brain development and behavioral functioning in polydrug-exposed children awaits further research.
Implementation and Case-Study Results of Potentially Better Practices to Improve Pain Management of Neonates
Authors: Dunbar Alston E. , Sharek Paul J. , Mickas Nick A. , Coker Kara L. , Duncan Jill , McLendon Debra , Pagano Claire , Puthoff Teresa D. , Reynolds Natalie L. , Powers Richard J. , Johnston C. Celeste 
Published: November 2006

OBJECTIVE. Collaborative quality improvement techniques were used to facilitate local quality improvement in the management of pain in infants. Several case studies are presented to highlight this process.METHODS. Twelve NICUs in the Neonatal Intensive Care Quality Improvement Collaborative 2002 focused on improving neonatal pain management and sedation practices. These centers developed and implemented evidence-based potentially better practices for pain management and sedation in neonates. The group introduced changes through plan-do-study-act cycles and tracked performance measures throughout the process.RESULTS. Strategies for implementing potentially better practices varied between centers on the basis of local characteristics. Individual centers identified barriers to implementation, developed tools for improvement, and shared their experience with the collaborative. Baseline data from the 12 sites revealed substantial opportunities for improved pain management, and local potentially better practice implementation resulted in measurable improvements in pain management at participating centers.CONCLUSIONS. The use of collaborative quality improvement techniques enhanced local quality improvement efforts and resulted in effective implementation of potentially better practices at participating centers.
Sorption and Transport of 17β‐Estradiol and Testosterone in Undisturbed Soil Columns
Authors: Sangsupan H. A. , Radcliffe D. E. , Hartel P. G. , Jenkins M. B. , Vencill W. K. , Cabrera M. L. 
Published: October 2006

ABSTRACTLand‐applied domestic animal wastes contain appreciable amounts of 17β‐estradiol (henceforth, estradiol) and testosterone. These sex hormones may be transported through soil to groundwater and streams, where they may adversely affect the environment. Previous column transport studies with these hormones used repacked soil and did not consider preferential flow. We, therefore, determined the sorption and transport characteristics of estradiol and testosterone in undisturbed soil columns (15‐cm i.d. by 32‐cm height). In the sorption experiment, isotherms for estradiol and testosterone were nonlinear with Freundlich exponents (n) less than one. Sorption of both hormones decreased with soil depth, and estradiol sorbed more strongly than testosterone. Average estradiol Freundlich sorption coefficients (Kf) values were 36.9 μg1 − n mLn g−1 for the 0‐ to 10‐cm soil depth and 25.7 μg1 − n mLn g−1 for the 20‐ to 30‐cm soil depth. Average testosterone Kf values were 26.7 μg1 − n mLn g−1 for the 0‐ to 10‐cm soil depth and 14.0 μg1 − n mLn g−1 for the 20‐ to 30‐cm soil depth. In the transport experiment, 27% of the estradiol and 42% of the testosterone leached through the soil columns. Approximately 50% of the remaining soil‐bound hormones were sorbed in the top 10 cm of soil. In almost all instances, breakthrough concentrations of estradiol, testosterone, and a chloride tracer peaked simultaneously. Simultaneous breakthrough and HYDRUS‐1D transport parameters indicated both chemical and physical nonequilibrium processes affected hormone transport. This suggests hormones placed on soil surfaces may contaminate groundwater under conditions of preferential flow.
Sewage Sludge Effects on Mesofauna and Cork Oak (Quercus suberL.) Leaves Decomposition in a Mediterranean Forest Firebreak
Authors: Pernin Céline , me Cortet Jér o ˆ , Joffre Richard , Le Petit Jean , Torre Franck 
Published: October 2006

ABSTRACTEffects of sewage sludge on litter mesofauna communities (Collembola and Acari) and cork oak (Quercus suberL.) leaf litter decomposition have been studied during 18 mo using litterbags in an in situ experimental forest firebreak in southeastern France. The sludge (2.74 t DM ha−1yr−1) was applied to fertilize and maintain a pasture created on the firebreak. Litterbag colonization had similar dynamics on both the control and fertilized plots and followed a typical Mediterranean pattern showing a greater abundance in spring and autumn and a lower abundance in summer. After 9 mo of litter colonization, Collembola and Acari, but mainly Oribatida, were more abundant on the sludge‐fertilized plot. Leaf litter decomposition showed a similar pattern on both plots, but it was faster on the control plot. Furthermore, leaves from the fertilized plot were characterized by greater nitrogen content. Both chemical composition of leaves and sludges and the decomposition state of leaves have significantly affected the mesofauna community composition from each plot.
Persistence of the Sulfonylurea Herbicides Thifensulfuron‐Methyl, Ethametsulfuron‐Methyl, and Metsulfuron‐Methyl in Farm Dugouts (Ponds)
Authors: Cessna Allan J. , Donald David B. , Bailey Jonathan , Waiser Marley , Headley J. V. 
Published: October 2006

ABSTRACTSulfonylurea herbicides are applied at relatively low rates (3 to 40 g ha−1) to control weeds in a variety of crops across the Canadian prairies. Because of their high phytotoxicity and the likelihood of their transport in surface runoff, there is concern about their possible impact to aquatic ecosystems. Little is known, however, about their persistence and behavior in aquatic ecosystems. To assess persistence in aquatic ecosystems, three prairie farm dugouts (ponds) were fortified with either thifensulfuron‐methyl {methyl 3‐[[[[(4‐methoxy‐6‐methyl‐1,3,5‐triazin‐2‐yl)amino]carbonyl]amino]sulfonyl]‐2‐thiophenecarboxylate}, ethametsulfuron‐methyl {methyl 2‐[[[[[4‐ethoxy‐6‐(methylamino)‐1,3,5‐triazin‐2‐yl]amino]carbonyl]amino]sulfonyl]benzoate} or metsulfuron‐methyl {methyl 2‐[[[[(4‐methoxy‐6‐methyl‐1,3,5‐triazinyl)amino]carbonyl]amino]sulfonyl]benzoate}. The decreasing order of persistence of environmentally relevant concentrations (1 to 4.6 μg L−1) of these herbicides in dugout water over the June to October period was metsulfuron‐methyl>ethametsulfuron‐methyl>thifensulfuron‐methyl. The corresponding dissipation half‐lives (DT50) of 84, 30, and 16 d, respectively, are in the same relative order as the recropping intervals for these herbicides. Thifensulfuron‐methyl showed a biphasic dissipation with slower dissipation during the winter months. In contrast, the dissipation of metsulfuron‐methyl, the sulfonylurea herbicide with the longest DT50, was somewhat enhanced under winter conditions. One of the major routes of sulfonylurea herbicide dissipation was removal from the water column when dugout water was lost during hydrological discharge. The relatively long persistence of these herbicides in water indicates that partitioning into sediments was minimal, the sulfonylurea and methyl ester linkages in these compounds were resistant to hydrolysis in weakly alkaline waters, and that microbial and photolytic degradation in dugout waters were slow.
Sources, Sinks, and Exposure Pathways of Lead in Urban Garden Soil
Authors: Clark Heather F. , Brabander Daniel J. , Erdil Rachel M. 
Published: October 2006

ABSTRACTThe chemistry of Pb in urban soil must be understood in order to limit human exposure to Pb in soil and produce and to implement remediation schemes. In inner‐city gardens where Pb contamination is prevalent and financial resources are limited, it is critical to identify the variables that control Pb bioavailability. Field‐portable X‐ray fluorescence was used to measure Pb in 103 urban gardens in Roxbury and Dorchester, MA, and 88% were found to contain Pb above the USEPA reportable limit of 400 μg g−1Phosphorus, iron, loss on ignition, and pH data were collected, Pb‐bearing phases were identified by X‐ray diffraction, and Pb isotopes were measured using inductively coupled plasma mass spectrometry. Four test crops were grown both in situ and in Roxbury soil in a greenhouse, and plant tissue was analyzed for Pb uptake by polarized energy‐dispersive X‐ray fluorescence. Variation at the neighborhood scale in soil mineralogical and chemical characteristics suggests that the bioavailable fraction of Pb in gardens is site specific. Based on Pb isotope analysis, two historical Pb sources appear to dominate the inventory of Pb in Roxbury gardens: leaded gasoline (207Pb/206Pb = 0.827) and Pb‐based paint (207Pb/206Pb = 0.867). Nearly 70% of the samples analyzed can be isotopically described by mixing these two end members, with Pb‐based paint contributing 40 to 80% of the mass balance. A simplified urban human exposure model suggests that the consumption of produce from urban gardens is equivalent to approximately 10 to 25% of children's daily exposure from tap water. Furthermore, analysis of over 60 samples of plant tissue from the four test species suggests that in these urban gardens unamended phytoremediation is an inadequate tool for decreasing soil Pb.
Tillage System, Application Rate, and Extreme Event Effects on Herbicide Losses in Surface Runoff
Authors: Shipitalo Martin J. , Owens Lloyd B. 
Published: October 2006

ABSTRACTConservation tillage can reduce soil loss; however, the residual herbicides normally used to control weeds are often detected in surface runoff at high levels, particularly if runoff‐producing storms occur shortly after application. Therefore, we measured losses of alachlor, atrazine, linuron, and metribuzin from seven small (0.45–0.79‐ha) watersheds for 9 yr (1993–2001) to investigate whether a reduced‐input system for corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] production with light disking, cultivation, and half‐rate herbicide applications could reduce losses compared with chisel and no‐till. As a percentage of application, annual losses were highest for all herbicides for no‐till and similar for chisel and reduced‐input. Atrazine was the most frequently detected herbicide and yearly flow‐weighted concentrations exceeded the drinking water standard of 3 μg L−1 in 20 out of 27 watershed years that it was applied. Averaged for 9 corn yr, yearly flow‐weighted atrazine concentrations were 26.3, 9.6, and 8.3 μg L−1 for no‐till, chisel, and reduced‐input, respectively. Similarly, flow‐weighted concentrations of alachlor exceeded the drinking water standard of 2 μg L−1 in 23 out of 54 application years and in all treatments. Thus, while banding and half‐rate applications as part of a reduced‐input management practice reduced herbicide loss, concentrations of some herbicides may still be a concern. For all watersheds, 60 to 99% of herbicide loss was due to the five largest transport events during the 9‐yr period. Thus, regardless of tillage practice, a small number of runoff events, usually shortly after herbicide application, dominated herbicide transport.
Influence of Irrigation Methods and an Adjuvant on the Persistence of Carbaryl on Pakchoi
Authors: Marutani Mari , Edirveerasingam Veronica 
Published: October 2006

ABSTRACTInfluence of irrigation methods and use of an adjuvant on the persistence of the carbaryl (1‐naphthyl N‐methylcarbamate) on pakchoi [Brassica rapa L. subsp. chinensis (Rupr.) Olsson] was studied using a commercial enzyme linked immunosorbent assay kit. After applying carbaryl at a.i. 10.6 g L−1 with or without an adjuvant (Latron B‐1956) to leaves, plants were provided water daily by either overhead or basal application. Pesticide residue on leaf tissues was examined immediately after pesticide application and on 2, 4, 6, and 8 d after pesticide application. Use of the adjuvant did not affect the initial deposit of the pesticide, however pesticide persistence was improved with the adjuvant regardless of irrigation. Overhead irrigation contributed to rapid loss of the pesticide by washing carbaryl from the leaf surface. The longest half‐life of carbaryl (6.5 d) was detected on plants receiving basal irrigation plus the adjuvant while the shortest half‐life (2 d) was observed when plants were treated with overhead irrigation and no adjuvant.
The Role of Lipids on Sorption Characteristics of Freshwater‐ and Wastewater‐Irrigated Soils
Authors: Drori Yaron , Lam Buuan , Simpson Andre , Aizenshtat Zeev , Chefetz Benny 
Published: October 2006

ABSTRACTThe soil lipid fraction can play an important role in the sorption of organic compounds. In this study, the impact of the lipid fraction of freshwater‐ and wastewater‐irrigated soils on the sorption of non‐ and relatively polar compounds was assessed. Lipid analyses revealed a clear difference between the two lipid fractions. The lipid extract from the wastewater‐irrigated soil was consistent with mainly straight paraffinic chain materials; the lipid extract from freshwater‐irrigated soil, on the other hand, exhibited stronger signals of aromatics, double bonds, ester, ether, and methyl, in addition to a smaller contribution from methylene protons. Our data suggest that lipid removal induced a stronger increase in the soil's sorption affinity for solutes capable of polar interactions such as atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐1,3,5‐triazine) and chlorotoluron (N′‐(3‐chloro‐4‐methylphenyl)‐N,N‐dimethylurea) as compared to phenanthrene. Moreover, the level of increase in sorption affinities due to lipid removal was much higher for the freshwater‐irrigated soil than for its wastewater‐irrigated counterpart, even though the level of lipids in the freshwater‐irrigated soil was half that in the wastewater‐irrigated one (6 vs. 11% of the total organic C). The higher level of polar functionalities, such as ether and ester moieties, in the lipid fraction from the freshwater‐irrigated soil suggests that these extractable compounds compete successfully with the polar solutes (atrazine and chlorotoluron) for specific binding sites in the soil organic matter (SOM). It appears that the composition of the lipid fraction may be a key consideration in unraveling the sorption of organic molecules in soils.
Estimating Source Coefficients for Phosphorus Site Indices
Authors: Elliott H. A. , Brandt R. C. , Kleinman P. J. A. , Sharpley A. N. , Beegle D. B. 
Published: October 2006

ABSTRACTPhosphorus release to runoff varies widely for different land‐applied organic P sources even when spread at equivalent total P rates. To address this variability, some P site indices include tabulated P source coefficients (PSCs) for differential weighting of applied P materials based on their runoff enrichment potential. Because runoff P can vary widely even within source categories depending on composition, storage, and treatment differences, this study explored a method for estimating PSCs based on the water‐extractable P (WEP) content of the applied amendment. Using seven published rainfall‐runoff studies that followed National Phosphorus Research Project protocols, runoff dissolved P (RDP) was correlated (r2 = 0.80) with WEP for multiple surface‐applied manures and biosolids. Assuming amendments with WEP ≥ 10 g kg−1 behave as highly soluble P sources and have a maximum PSC of 1.0, an empirical equation was developed for computing source‐specific PSCs from laboratory‐determined WEP values [PSC = 0.102 × WEP0.99]. For two independent runoff experiments, correlations between RDP loss and P source loading rate were improved when loading rates were multiplied by the computed (r2 = 0.73–0.86) versus generic (r2 = 0.45–0.48) PSCs. Source‐specific PSCs should enhance the ability of assessment tools to identify vulnerable sites and P loss management alternatives, although the exact inclusion process depends on index scaling and conceptual framework.
Nitrate and Sediment Fluxes from a California Rangeland Watershed
Authors: Lewis David J. , Singer Michael J. , Dahlgren Randy A. , Tate Kenneth W. 
Published: October 2006

ABSTRACTLong‐term water quality records for assessing natural variability, impact of management, and that guide regulatory processes to safeguard water resources are rare for California oak woodland rangelands. This study presents a 20‐yr record (1981–2000) of nitrate‐nitrogen (NO3–N) and suspended sediment export from a typical, grazed oak woodland watershed (103 ha) in the northern Sierra Nevada foothills of California. Mean annual precipitation over the 20‐yr period was 734 mm yr−1 (range 366–1205 mm yr−1). Mean annual stream flow was 353 mm y−1 (range 87–848 mm yr−1). Average annual stream flow was 48.1 ± 16% of precipitation. Mean annual NO3–N export was 1.6 kg ha−1 yr−1 (range 0.18–3.6 kg ha−1 yr−1). Annual NO3–N export significantly (P < 0.05) increased with increasing annual stream flow and precipitation. Mean daily NO3–N export was 0.004 kg ha−1 d−1 (range 10−5 to 0.55 kg ha−1 d−1). Mean annual suspended sediment export was 198 kg ha−1 yr−1 (range 23–479 kg ha−1 yr−1). There was a positive relationship (P < 0.05) between annual suspended sediment export, annual stream flow and precipitation. Mean daily suspended sediment export was 0.54 kg ha−1 d−1 (range 10−4 to 155 kg ha−1 d−1). Virtually no sediment was exported during the dry season. The large variation in daily and annual fluxes highlights the necessity of using long‐term records to establish quantitative water quality targets for rangelands and demonstrates the difficulty of designing a water quality monitoring program for these ecosystems.
A Solid‐Phase Microextraction Chamber Method for Analysis of Manure Volatiles
Authors: Miller Daniel N. , Woodbury Bryan L. 
Published: October 2006

ABSTRACTOdors from livestock operations are a complex mixture of volatile carbon, sulfur, and nitrogen compounds. Currently, detailed volatiles analysis is both time consuming and requires specialized equipment and methods. This work describes a new method that utilizes a dynamic flux chamber, solid‐phase microextraction (SPME), and gas chromatography–mass spectroscopy (GC–MS) to describe and compare the odorous compounds emitted from cattle and swine feces. Evaluation of method parameters produced a protocol for comparing relative emissions based on fixed sample temperature (20°C) and exposed surface area (approximately 523 cm2), air flow rates (1 L min−1 or 16 cm s−1), SPME exposure time (5 min), and chamber cleaning procedures (70% ethanol rinse and drying for 30 min at 105°C) to minimize cross‐contamination between samples. A variety of volatile organic compounds (VOCs) including alcohols, volatile fatty acids, aromatic ring compounds, ketones, esters, and sulfides were routinely detected and the relative emissions from fresh and incubated (37°C overnight) swine and cattle feces were compared as a measure of potential to produce odorants during manure storage. Differences in the types and relative quantities of volatiles emitted were detected when animal species (cattle or swine), diet, fecal incubation, or sample storage conditions (20, 4, or −20°C) were varied.
Occurrence and Rates of Terminal Electron‐Accepting Processes and Recharge Processes in Petroleum Hydrocarbon‐Contaminated Subsurface
Authors: Salminen Jani M. , Hänninen Pekka J. , Leveinen Jussi , Lintinen Petri T. J. , J⊘rgensen Kirsten S. 
Published: October 2006

ABSTRACTThe occurrence and rates of terminal electron acceptor processes, and recharge processes in the unsaturated zone of a boreal site contaminated with petroleum hydrocarbons in the range C10 to C40 were examined. Soil microcosms were used to determine the rates of denitrification, iron (Fe) reduction, sulfate (SO4) reduction, and methanogenesis in two vertical soil profiles contaminated with oil, and in a noncontaminated reference sample. Furthermore, the abundances of the 16S rRNA genes belonging to Geobacteracaea in the samples were determined by real‐time quantitative polymerase chain reaction (PCR). Analyses of ground water chemistry and soil gas composition were also performed together with continuous in situ monitoring of soil water and ground water chemistry. Several lines of evidence were obtained to demonstrate that both Fe reduction and methanogenesis played significant roles in the vertical profiles: Fe reduction rates up to 3.7 nmol h−1 g−1 were recorded and they correlated with the abundances of the Geobacteracaea 16S rRNA genes (range: 2.3 × 105 to 4.9 × 107 copies g−1). In the ground water, ferrous iron (Fe2+) concentration up to 55 mg L−1 was measured. Methane production rates up to 2.5 nmol h−1 g−1 were obtained together with methane content up to 15% (vol/vol) in the soil gas. The continuous monitoring of soil water and ground water chemistry, microcosm experiments, and soil gas monitoring together demonstrated that the high microbial activity in the unsaturated zone resulted in rapid removal of oxygen from the infiltrating recharge thus leaving the anaerobic microbial processes dominant below 1.5 m depth both in the unsaturated and the saturated zones of the subsurface.