bluuebunny/crossref_metadata_2025 huggingface dataset:
Catching Butterflies
Authors: Wang Ping
Published: June 2008

Adopting a linguistic-based stylistic approach, this article proposes a new interpretation of classical Chinese ci-poetry by Li Yu (937-978) and Li Qingzhao (1084-1155?). Based on Halliday’s Functional Grammar, analysing the three contextual meanings interwoven in the dense fabric of the poetic discourse, taking into account also of deviation and foregrounding, this study challenges the traditional Chinese dichotomy of wanyue and haofang schools. It argues that although both Li Yu and Li Qingzhao are regarded as, arguably, most important representative poets of wanyue style, their poetry is in fact quite different from wanyue convention. By accounting for certain judgments of value made on an intuitive basis by a comparatively objective and consistent procedure, this paper hopes to shed new light on the characteristics of the lyrics by Li Yu and Li Qingzhao. It also demonstrates how a combination of traditional Chinese scholarship - marked for the most part by its intuitive and impressionistic approach - and a more systematic and analytical Western methodology may enlarge the horizons of Chinese literary studies, while also enhancing the ability of Westerners to appreciate classical Chinese poetry.
Misoprostol Effects on Diclofenac‐Induced Cardiorenal Changes in Salt‐Sensitive Patients with Hypertension: The MEDIC Study
Authors: Munger Mark A. , Gardner Stephanie F. , Ateshkadi Arasb , Rabetoy Gary M. , Barri Yoursi M. , Stoddard Gregory J. , Cheung Alfred K.
Published: June 2008

Study Objective. To determine whether coadministration of misoprostol with the nonsteroidal antiinflammatory drug diclofenac lessens the increase in blood pressure and improves the alterations in renal hemodynamics induced by diclofenac.

Design. Prospective, randomized, double‐blind, placebo‐controlled, crossover study.

Setting. Two university research centers.

Patients. Nineteen senior (mean age 62 yrs [range 55–73 yrs]), salt‐sensitive patients with stage 1 or 2 hypertension.

Intervention. After a 3‐week antihypertensive withdrawal lead‐in phase, patients received either diclofenac 75 mg alone or diclofenac 75 mg plus misoprostol 200 μg twice/day for 14 days. After a 10‐day washout period, patients received the alternate treatment.

Measurements and Main Results. Blood pressure was measured by 24‐hour ambulatory blood pressure monitoring, effective renal plasma flow (ERPF) rate was determined by para‐aminohippurate clearance, and glomerular filtration rate (GFR) was measured by iothalamate clearance. Mean arterial pressure (MAP = diastolic blood pressure + 0.33[systolic ‐ diastolic blood pressure]) and rate‐pressure product (RPP = systolic blood pressure x heart rate x 10−2) were also used to compare treatment groups. Diclofenac alone increased MAP by a mean ± SEM of 5.0 ± 1.0 mm Hg and RPP by 337 ± 181 units compared with baseline. The ERPF rate and GFR decreased by 40.5 ± 26.9 ml/minute and 14.1 ± 6.5 ml/minute, respectively. Diclofenac plus misoprostol decreased the diclofenac‐induced increase in MAP by 3.3 ± 1.0 mm Hg (95% confidence interval [CI] 1.1–5.3 mm Hg, p=0.004) and decreased the RPP by 724 ± 238 units (95% CI 225–1223 units, p=0.007). The ERPF rate increased by 56.1 ± 35.0 ml/minute (95% CI −24.7–137.0 ml/min, p=0.15) and GFR by 18.1 ± 7.1 ml/minute (95% CI 1.9–34.5 ml/min, p=0.03). Diclofenac alone was relatively well tolerated; no adverse effects were reported with diclofenac plus misoprostol.

Conclusion. In senior salt‐sensitive patients with hypertension, coadministration of misoprostol with diclofenac attenuated the blood pressure elevation and renal vasoconstrictive effects of diclofenac and was well tolerated.
Physician Adherence to Blood Pressure Guidelines and Its Effect on Seniors
Authors: Milchak Jessica L. , Carter Barry L. , Ardery Gail , Dawson Jeffrey D. , Harmston Matt , Franciscus Carrie L.
Published: June 2008

Study Objective. To compare physician adherence to guidelines from the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure for patients younger than 65 years of age with those aged 65 years and older, and to analyze whether factor groupings (subsets of criteria used to determine adherence) were predictive of blood pressure control.

Design. Retrospective medical record review.

Setting. Five university‐affiliated family medicine and internal medicine outpatient clinics.

Patients. One hundred seventy‐nine patients (age range 21–85 yrs) with uncontrolled hypertension: 105 patients were younger than 65 years (nonsenior), and 74 patients were 65 years or older (senior).

Measurements and Main Results. Data abstracted from each patient's medical record were used to evaluate adherence to 17 process‐of‐care criteria, identified to assess physician adherence to the guidelines. A computer algorithm generated scores for each criterion as well as an overall adherence score. The relationship between the adherence score and blood pressure control was then examined. Separate factor analyses were conducted to ascertain differences in the way that the criteria were grouped. Factor scores were calculated for each patient, and the scores were evaluated in the context of blood pressure control. Guideline adherence scores were significantly higher for nonsenior patients than for senior patients (59.3% vs 56.1%, p=0.024). Blood pressure control rate was also higher, although not significantly, in nonseniors versus seniors (68.6% vs 56.8%, p=0.063). No factors in the senior group were significantly associated with blood pressure control, but one was significantly correlated in the nonsenior group (p<0.0001). It included diuretic therapy, adjusting a drug when a patient's blood pressure was uncontrolled, documentation of uncontrolled blood pressure in the medical record at the visit, documentation of the correct blood pressure goal, documentation of cardiovascular risk factors, and measurement of urine albumin level.

Conclusion. Overall physician adherence to blood pressure guidelines was significantly higher for the nonsenior group than for the senior group. Similarly, control of blood pressure was better in the nonsenior group. However, no significant relationship between overall adherence scores and blood pressure control was found in either group. In nonseniors, one factor grouping was significantly correlated with blood pressure control. Future studies should evaluate the process‐of‐care criteria to determine if and how they are related to blood pressure control in senior patients.
Pharmacokinetics and Pharmacodynamics of Methadone Enantiomers After Coadministration with Fosamprenavir‐Ritonavir in Opioid‐Dependent Subjects
Authors: Cao Ying‐Jun , Smith Patrick F. , Wire Mary Beth , Lou Yu , Lancaster Charles T. , Causon Roger C. , Bigelow George E. , Martinez Elizabeth , Fuchs Edward J. , Radebaugh Christine , McCabe Sarah , Hendrix Craig W.
Published: June 2008

Study Objective. To compare steady‐state pharmacokinetics and pharmacodynamics of methadone enantiomers when coadministered with fosamprenavir 700 mg‐ritonavir 100 mg twice/day.

Design. Open‐label, single‐sequence, two‐period crossover, drug‐interaction study.

Setting. Two university‐affiliated research centers.

Subjects. Twenty‐six opioid‐dependent, methadone‐maintained, healthy adults.

Intervention. Subjects received their usual daily dose of methadone alone for 4 days (period 1). Subjects then received the same daily dose of methadone plus fosamprenavir 700 mg‐ritonavir 100 mg twice/day for 14 days (period 2).

Measurements and Main Results. Blood was collected on days 1–4 (period 1) and on days 11–14 (period 2) for plasma R‐ and S‐methadone concentrations; amprenavir concentrations were assessed during period 2. Opioid‐effect measures were assessed in each study period. Subjects served as their own controls for comparison of period 1 with period 2. Coadministration of fosamprenavir‐ritonavir with methadone reduced plasma total R‐methadone area under the plasma concentration‐time curve over the dosing interval at steady state (AUCẗ‐ss) by 18%, maximum concentration at steady state (Cmax‐ss) by 21%, and concentration at the end of the dosing interval at steady state (Cẗ‐ss) by 11%; time to reach Cmax‐ss (Tmax) was delayed by 1.75 hours. Coadministration of fosamprenavir‐ritonavir with methadone also reduced plasma total S‐methadone AUCẗ‐ss and Cmax‐ss by 43% each, Cẗ‐ss by 41%, and delayed Tmax by 0.85 hours. Fosamprenavir‐ritonavir administered with methadone did not alter plasma amprenavir pharmacokinetics compared with historical control data; nor did it alter the unbound R‐methadone at 2 and 6 hours after methadone dosing. Pharmacodynamic indexes remained essentially unchanged after adding fosamprenavir‐ritonavir to methadone. No subject demonstrated opioid intoxication or withdrawal, or requested methadone dosage modification.

Conclusion. No adjustment in the dosages of either methadone or fosamprenavir 700 mg‐ritonavir 100 mg twice/day is required during coadministration, on the basis of the small reduction in total R‐methadone exposure, no change in unbound R‐methadone, no clinically important opioid effects, and no change in amprenavir exposure.
Evaluation of a Potential Tigecycline‐Warfarin Drug Interaction
Authors: Zimmerman James J. , Raible Donald G. , Harper Dawn M. , Matschke Kyle , Speth John L.
Published: June 2008

Study Objective.To evaluate the potential for a clinically significant drug interaction between tigecycline and warfarin by using pharmacokinetic and anticoagulant assessments.

Design.Open‐label, nonrandomized study.

Setting.Inpatient clinical pharmacology unit.

Subjects.Nineteen healthy male volunteers were enrolled; eight completed all study assessments.

Intervention.All subjects received a single oral dose of warfarin 25 mg (day 1). Seven days later (day 8), they received a 100‐mg loading dose of intravenous tigecycline, followed by 50 mg every 12 hours for eight additional doses. On day 12, they received another single oral dose of warfarin 25‐mg with their last dose of tigecycline.

Measurements and Main Results.Serum tigecycline and plasma R‐ and S‐warfarin concentrations were determined by high‐performance liquid chromatography with tandem mass spectroscopy. Pharmacokinetic parameters were calculated by using noncompartmental methods and analyzed by the two 1‐sided tests equivalence procedure. Pharmacodynamic analyses were based on anticoagulant parameters derived from international normalized ratios of prothrombin times. Tigecycline peak concentration, trough concentration, area under the concentration‐time curve (AUC) from 0–12 hrs, and clearance were not affected by single‐dose warfarin. In contrast, R‐ and S‐warfarin AUC from time zero extrapolated to infinity was increased by 68% and 29%, respectively, and clearance was decreased by 40% and 23%, respectively, when warfarin was administered after eight doses of tigecycline. Nevertheless, tigecycline did not alter the anticoagulant effects of warfarin, which is consistent with a mechanism based only on increased warfarin protein binding.

Conclusion.These results suggest that a dosage adjustment of either drug is not necessary during coadministration of tigecycline and warfarin. However, consistent with good medical practice, the anticoagulant activity of warfarin should be monitored during coadministration with tigecycline.
Pharmacotherapy for Heart Failure with Left Ventricular Dysfunction: Beyond Angiotensin‐Converting Enzyme Inhibitors and β‐Blockers
Authors: Norgard Nicholas B. , Stark Jennifer E.
Published: June 2008

Angiotensin‐converting enzyme (ACE) inhibitors and β‐blockers make up the cornerstone of therapy for patients with heart failure involving left ventricular dysfunction. These drug classes have been proven to decrease morbidity and mortality in patients with heart failure. Unfortunately, many patients remain symptomatic and experience disease progression despite taking both an ACE inhibitor and a β‐blocker. Others may be unable to tolerate one or both of these agents. In recent years, several other drug classes have been shown to provide additional morbidity and mortality benefits in patients with heart failure. These include angiotensin II receptor blockers (ARBs), aldosterone antagonists, and the combination of isosorbide dinitrate plus hydralazine. To select the most appropriate drug therapy for patients with heart failure, clinicians should consider results from clinical trials in specific patient populations, adverse‐event profiles, tolerability, cost, and dosing regimens.
A Multimodal, Evidence‐Based Approach to Achieve Lipid Targets in the Treatment of Antiretroviral‐Associated Dyslipidemia: Case Report and Review of the Literature
Authors: Bain Amy M. , White Elizabeth A. , Rutherford William S. , Rahman Anita P. , Busti Anthony J.
Published: June 2008

Metabolic abnormalities associated with the treatment of human immunodeficiency virus (HIV) infection are well‐recognized problems that increase cardiovascular risk. As a result of the complexity of treating both HIV‐ and antiretroviral‐related comorbidities, strategies that improve adverse drug events while maintaining viral control are in critical need. Although guidelines have somewhat helped in the general approach and in first‐line strategies for managing dyslipidemia in patients receiving antiretrovirals, a paucity of data exist to guide clinicians in treating patients whose conditions are refractory to first‐line options or who are at substantial risk for cardiovascular events. Further complicating the choice of lipid‐lowering strategy is the lack of randomized controlled data from the HIV‐affected population and a concern about clinically significant drug‐drug interactions. We describe an HIV‐infected patient with efavirenz‐associated dyslipidemia at very high cardiovascular risk who had not achieved his primary or secondary lipid goals despite 2 years of treatment in a lipid specialty clinic. Lipid control was accomplished in 10 weeks with a targeted, stepwise approach of switching efavirenz to nevirapine, followed by rosuvastatin 20 mg/day, which was sustained for at least 10 months. Of most importance, this outcome was achieved without any clinically significant alteration in virologic or immunologic control. This case report highlights the potential for a pharmacist‐guided, multistep approach that addresses HIV‐related dyslipidemia and incorporates the pharmacokinetic literature to guide lipid‐lowering therapy and promote the attainment of goals based on current standards of care.
Elevated Serum Tobramycin Concentrations After Treatment with Tobramycin Inhalation in a Preterm Infant
Authors: Abdulhamid Ibrahim , Wise Terri L. , Andrews Stephanie , Biglin Kevin , Lehr Victoria Tutag
Published: June 2008

High‐dose inhaled tobramycin has been increasingly used for treatment and suppression of Pseudomonas aeruginosa pulmonary infections, especially in patients with cystic fibrosis. The advantage of inhalation over other routes of administration is minimal systemic absorption, which reduces the potential for adverse effects. However, cases of adults who had elevated serum concentrations and experienced systemic adverse effects due to excessive systemic absorption after inhaled tobramycin have been reported. We describe a prematurely born infant with numerous congenital and acquired disorders who required assisted mechanical ventilation and a 60‐day stay in the neonatal intensive care unit (NICU). Tracheostomy and mechanical ventilatory support were required throughout the infant's hospital stay. The patient developed several pulmonary infections caused by various bacteria. He was treated with multiple antibiotics, including two different dose preparations of inhaled tobramycin 80 mg and 300 mg, administered through the tracheostomy and the ventilator. The infant was given a total of five preparations of tobramycin 80 mg/dose and three of 300 mg/dose, for a total cumulative dose of 1300 mg over a 6‐day period. His tobramycin concentrations increased, prompting discontinuation of the inhaled tobramycin. The infant died on day 60. To our knowledge, this is the first report of elevated tobramycin concentrations after inhalation in an infant. Although studies have found that tobramycin is safe and effective, certain patient populations are more at risk for toxicity. Tobramycin concentrations should be closely monitored in patients with significant underlying renal disorders, especially those in age‐group extremes.
Role of vesicular monoamine transporter type 2 in rodent insulin secretion and glucose metabolism revealed by its specific antagonist tetrabenazine
Authors: Raffo Anthony , Hancock Kolbe , Polito Teresa , Xie Yuli , Andan Gordon , Witkowski Piotr , Hardy Mark , Barba Pasquale , Ferrara Caterina , Maffei Antonella , Freeby Matthew , Goland Robin , Leibel Rudolph L , Sweet Ian R , Harris Paul E
Published: June 2008

Despite different embryological origins, islet β-cells and neurons share the expression of many genes and display multiple functional similarities. One shared gene product, vesicular monoamine transporter type 2 (VMAT2, also known as SLC18A2), is highly expressed in human β-cells relative to other cells in the endocrine and exocrine pancreas. Recent reports suggest that the monoamine dopamine is an important paracrine and/or autocrine regulator of insulin release by β-cells. Given the important role of VMAT2 in the economy of monoamines such as dopamine, we investigated the possible role of VMAT2 in insulin secretion and glucose metabolism. Using a VMAT2-specific antagonist, tetrabenazine (TBZ), we studied glucose homeostasis, insulin secretion both in vivo and ex vivo in cultures of purified rodent islets. During intraperitoneal glucose tolerance tests, control rats showed increased serum insulin concentrations and smaller glucose excursions relative to controls after a single intravenous dose of TBZ. One hour following TBZ administration we observed a significant depletion of total pancreas dopamine. Correspondingly, exogenous l-3,4-dihydroxyphenylalanine reversed the effects of TBZ on glucose clearance in vivo. In in vitro studies of rat islets, a significantly enhanced glucose-dependent insulin secretion was observed in the presence of dihydrotetrabenazine, the active metabolite of TBZ. Together, these data suggest that VMAT2 regulates in vivo glucose homeostasis and insulin production, most likely via its role in vesicular transport and storage of monoamines in β-cells.
Production Optimization through Utilization of Innovative Technologies in an Offshore Field Environment
Authors: Zorbalas K. I. , Omaireen K. I. , Yateem K. S.
Published: June 2008

Several innovative techniques and practices have been recently implemented to improve well production performance in offshore assets in the Arabian Gulf. The challenges which followed past practices were identified and intensive work was focused on enhancements to existing well completions to increase well productivity and prevent premature water or gas encroachment.

This paper describes several innovative concepts implemented in three major offshore fields in Saudi Aramco. The methodologies of four technologies which were tested and implemented in the recent years are presented. These technologies are the practice of sidetracking horizontal wells and completed with passive inflow screens, the use of reservoir gas cap for artificial lift of oil wells, the Tornado technique for sand fill clean-out and the chemical treatment of wells which endured formation damage.

All these technologies proved to be successful and their combined application added value to Saudi Aramco's operations. As a result, the production targets for 2006 were met and the positive results obtained from the implementation of these technologies will lead to the optimization and improvement of future operational practices.
Interactions between Chromium and Sulfur Metabolism inBrassica juncea
Authors: Schiavon Michela , Pilon‐Smits Elizabeth A.H. , Wirtz Markus , Hell Rüdiger , Malagoli Mario
Published: June 2008

The effects of chromate on sulfate uptake and assimilation were investigated in the accumulatorBrassica juncea(L.) Czern. Seven‐day‐old plants were grown for 2 d under the following combination of sulfate and chromate concentration: (i) no sulfate and no chromate (−S), (ii) no sulfate and 0.2 mmol L−1chromate (−S +Cr), (iii) 1 mmol L−1sulfate and no chromate (+S), or (iv) 1 mmol L−1sulfate and 0.2 mmol L−1chromate (+S +Cr). Despite the toxic effects exerted by chromate as indicated by altered level of reducing sugars and proteins in leaves, the growth ofB. junceawas only weakly reduced by chromate, and no variation in chlorophyllaandbwas measured, regardless of S availability. Chromium (Cr) was stored more in roots than in leaves, and the maximum Cr accumulation was measured in −S +Cr plants. The significant decrease of the sulfate uptake rates observed in Cr‐treated plants was accompanied by a repression of the root low‐affinity sulfate transporter (BjST1), suggesting that the transport of chromate inB. junceamay involve sulfate carriers. Once absorbed, chromate induced genes involved in sulfate assimilation (ATP‐sulfurylase:atps6; APS‐reductase:apsr2; Glutathione synthethase:gsh2) and accumulation of cysteine and glutathione, which may suggest that these reduced S compounds play a role in Cr tolerance. Together, our findings indicate that when phytoremediation technologies are used to recover Cr‐contaminated areas, the concentration of sulfate in the plant growth medium must be considered because it may influence the ability of plants to accumulate and tolerate Cr.
Levels of Dioxins in Soil and Corn Tissues after 30 Years of Biosolids Application
Authors: Hundal Lakhwinder S. , Cox Albert , Granato Thomas C. , Abedin Zainul
Published: June 2008

Detectable levels of dioxins have been reported in biosolids, but very little information is available on the effect of long‐term application of biosolids on dioxins accumulation in soil and uptake by plants. We analyzed dioxins in soil and corn tissue samples from field plots after 30 continuous applications of biosolids at 0 (Control), 16.8, and 67.2 Mg biosolids ha−1 yr−1 resulting in 0, 504, and 2016 Mg ha−1 cumulative loadings of biosolids, respectively. The levels of dioxins in soil were only 79.9, 115.5, and 247.5 ng toxic equivalents (TEQs) kg−1 in the 0, 504, and 2016 Mg biosolids ha−1 plots, respectively. Dioxins were not detected in the corn grain, and only trace levels (6.8–7.5 ng TEQs kg−1) were found in the corn stover; however, these values were not statistically different between control and biosolids‐amended soils. These observations suggest that although long‐term application of biosolids may increase the levels of dioxins in soil, it does not affect dioxins uptake by corn.
Sequential Concentration of Bacteria and Viruses from Marine Waters using a Dual Membrane System
Authors: Abdelzaher A. M. , Solo‐Gabriele H. M. , Wright M. E. , Palmer C. J.
Published: June 2008

The ability to rapidly and effectively concentrate diverse microbes is an essential component for monitoring water quality at recreational beaches. The purpose of this study was to develop a 0.45 μm pore size dual membrane system, which can sequentially concentrate both viruses and bacteria. The top PVDF membrane was used to filter bacteria by physical straining while the bottom HA membrane retained viruses through adsorption. The recovery of this system was assessed using test organisms: enterococci and somatic coliphage. Volumes of 100 to 400 mL of unspiked and sewage‐spiked beach water were filtered through both types of membranes. The PVDF membrane recovered statistically equivalent amounts of enterococci when compared to traditional membranes. All of the coliphage passed through the PVDF membrane, while 22% passed through the HA membrane. Increasing the volume from 100 to 400 mL did not significantly influence recoveries. Up to 35% of coliphage was eluted from the bottom membrane using beef extract solution. Rinsing bottom membranes with 0.5 mmol L−1 H2S04 was found to deactivate somatic coliphage. This research demonstrates the potential of using a dual membrane adsorption system for the concentration of both bacteria and viruses from recreational beaches. A proposed bi‐layer filtration system can be designed for simultaneous bacteria and virus filtration. Future experiments should focus on measurements utilizing additional bacteria and viruses.
High Biomass Removal Limits Carbon Sequestration Potential of Mature Temperate Pastures
Authors: Skinner R. Howard
Published: June 2008

Decades of plowing have depleted organic C stocks in many agricultural soils. Conversion of plowed fields to pasture has the potential to reverse this process, recapturing organic matter that was lost under more intensive cropping systems. Temperate pastures in the northeast USA are highly productive and could act as significant C sinks. However, such pastures have relatively high biomass removal as hay or through consumption by grazing animals. In addition, the ability to sequester C decreases over time as previously depleted stocks are replenished and the soil returns to equilibrium conditions. The objective of this research was to use eddy covariance systems to quantify CO2 fluxes over two fields in central Pennsylvania that had been managed as pastures for at least 35 yr. Net ecosystem exchange measurements averaged over 8 site‐years suggested that the pastures were acting as small net C sinks of 19 g C m−2 yr−1 (positive values indicate uptake). However, when biomass removal and manure deposition were included to calculate net biome productivity, the pastures were a net source of −81 g C m−2 yr−1 (negative values indicate loss to the atmosphere). Manure generated from the hay that was consumed off site averaged 18 g C m−2 yr−1 Returning that manure to the pastures would have only partially replenished the lost C, and the pastures would have remained net C sources. Heavy use of the biomass produced on these mature pastures prevented them from acting as C sinks.
Chemistry and Long‐Term Decomposition of Roots of Douglas‐Fir Grown under Elevated Atmospheric Carbon Dioxide and Warming Conditions
Authors: Chen H. , Rygiewicz P. T. , Johnson M. G. , Harmon M. E. , Tian H. , Tang J. W.
Published: June 2008

Elevated atmospheric CO2 concentrations and warming may affect the quality of litters of forest plants and their subsequent decomposition in ecosystems, thereby potentially affecting the global carbon cycle. However, few data on root tissues are available to test this feedback to the atmosphere. In this study, we used fine (diameter ≤ 2 mm) and small (2–10 mm) roots of Douglas‐fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings that were grown for 4 yr in a 2 × 2 factorial experiment: ambient or elevated (+ 180 ppm) atmospheric CO2 concentrations, and ambient or elevated (+3.8°C) atmospheric temperature. Exposure to elevated CO2 significantly increased water‐soluble extractives concentration (%WSE), but had little effect on the concentration of N, cellulose, and lignin of roots. Elevated temperature had no effect on substrate quality except for increasing %WSE and decreasing the %lignin content of fine roots. No significant interaction was found between CO2 and temperature treatments on substrate quality, except for %WSE of the fine roots. Short‐term (≤ 9 mo) root decomposition in the field indicated that the roots from the ambient CO2 and ambient temperature treatment had the slowest rate. However, over a longer period of incubation (9–36 mo) the influence of initial substrate quality on root decomposition diminished. Instead, the location of the field incubation sites exhibited significant control on decomposition. Roots at the warmer, low elevation site decomposed significantly faster than the ones at the cooler, high elevation site. This study indicates that short‐term decomposition and long‐term responses are not similar. It also suggests that increasing atmospheric CO2 had little effect on the carbon storage of Douglas‐fir old‐growth forests of the Pacific Northwest.
EPIC Modeling of Soil Organic Carbon Sequestration in Croplands of Iowa
Authors: Causarano Hector J. , Doraiswamy Paul C. , McCarty Gregory W. , Hatfield Jerry L. , Milak Sushil , Stern Alan. J.
Published: June 2008

Depending on management, soil organic carbon (SOC) is a potential source or sink for atmospheric CO2 We used the EPIC model to study impacts of soil and crop management on SOC in corn (Zea mays L.) and soybean (Glycine max L. Merr.) croplands of Iowa. The National Agricultural Statistics Service crops classification maps were used to identify corn–soybean areas. Soil properties were obtained from a combination of SSURGO and STATSGO databases. Daily weather variables were obtained from first order meteorological stations in Iowa and neighboring states. Data on crop management, fertilizer application and tillage were obtained from publicly available databases maintained by the NRCS, USDA‐Economic Research Service (ERS), and Conservation Technology Information Center. The EPIC model accurately simulated state averages of crop yields during 1970–2005 (R2 = 0.87). Simulated SOC explained 75% of the variation in measured SOC. With current trends in conservation tillage adoption, total stock of SOC (0–20 cm) is predicted to reach 506 Tg by 2019, representing an increase of 28 Tg with respect to 1980. In contrast, when the whole soil profile was considered, EPIC estimated a decrease of SOC stocks with time, from 1835 Tg in 1980 to 1771 Tg in 2019. Hence, soil depth considered for calculations is an important factor that needs further investigation. Soil organic C sequestration rates (0–20 cm) were estimated at 0.50 to 0.63 Mg ha−1 yr−1 depending on climate and soil conditions. Overall, combining land use maps with EPIC proved valid for predicting impacts of management practices on SOC. However, more data on spatial and temporal variation in SOC are needed to improve model calibration and validation.
Profile Analysis and Modeling of Reduced Tillage Effects on Soil Nitrous Oxide Flux
Authors: Venterea Rodney T. , Stanenas Adam J.
Published: June 2008

The impact of no‐till (NT) and other reduced tillage (RT) practices on soil to atmosphere fluxes of nitrous oxide (N2O) are difficult to predict, and there is limited information regarding strategies for minimizing fluxes from RT systems. We measured vertical distributions of key microbial, chemical, and physical properties in soils from a long‐term tillage experiment and used these data as inputs to a process‐based model that accounts for N2O production, consumption, and gaseous diffusion. The results demonstrate how differences among tillage systems in the stratification of microbial enzyme activity, chemical reactivity, and other properties can control N2O fluxes. Under nitrification‐dominated conditions, simulated N2O emissions in the presence of nitrite () were 2 to 10 times higher in NT soil compared to soil under conventional tillage (CT). Under denitrification‐dominated conditions in the presence of nitrate (), higher bulk density and water content under NT promoted higher denitrification rates than CT. These effects were partially offset by higher soluble organic carbon and/or temperature and lower N2O reduction rates under CT. The NT/CT ratio of N2O fluxes increased as or was placed closer to the surface. The highest NT/CT ratios of N2O flux (>30:1) were predicted for near‐surface placement, while NT/CT ratios < 1 were predicted for placement below 15 cm. These results suggest that N2O fluxes from RT systems can be minimized by subsurface fertilizer placement and by using a chemical form of fertilizer that does not promote substantial accumulation.
Avoided Deforestation as a Greenhouse Gas Mitigation Tool: Economic Issues
Authors: Sohngen Brent , Beach Robert H. , Andrasko Kenneth
Published: June 2008

Tropical deforestation is a significant contributor to accumulation of greenhouse gases (GHGs) in the atmosphere. GHG emissions from deforestation in the tropics were in the range of 1 to 2 Pg C yr−1for the 1990s, which is equivalent to as much as 25% of global anthropogenic GHG emissions. While there is growing interest in providing incentives to avoid deforestation and consequently reduce net carbon emissions, there is limited information available on the potential costs of these activities. This paper uses a global forestry and land use model to analyze the potential marginal costs of reducing net carbon emissions by avoiding deforestation in tropical countries. Our estimates suggest that about 0.1 Pg C yr−1of emissions reductions could be obtained over the next 30 to 50 yr for $5 per Mg C, and about 1.6 Pg C yr−1could be obtained over the same time frame for $100 per Mg C. In addition, the effects of carbon incentives on land use could be substantial. Relative to projected baseline conditions, we find that there would be around 3 million additional hectares (ha) of forestland in 2055 at $5 per Mg C and 422 million ha at $100 per Mg C. Estimates of reductions in area deforested, GHG mitigation potential, and annual land rental payments required are presented, all of which vary by region, carbon price paid, and time frame of mitigation.
Effect of Liquid Cow Manure on Andisol Properties and Atrazine Adsorption
Authors: Briceño Gabriela , Demanet Rolando , de la Luz Mora María , Palma Graciela
Published: June 2008

Application of animal manure amendments to agricultural soils is a common practice to improve soil fertility through the addition of essential plant nutrients. This practice may increase the potential for atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐1, 3, 5‐triazine) leaching due to competition for adsorption sites between the pesticide and dissolved organic carbon (DOC) added through manure. We evaluated the influence of liquid cow manure (LCM) application on soil properties, atrazine adsorption, and the physicochemical controlling mechanisms in an Andisol. The LCM was applied at rates equivalent to 0, 100,000, 200,000, and 300,000 L ha−1, resulting in treatments S‐0, S‐100, S‐200, and S‐300, respectively. The LCM application increased DOC and pH of the soils immediately on addition, but pH returned to S‐0 values 30 d after application. The LCM application did not modify atrazine adsorption with the two lowest application rates (S‐100 and S‐200), but atrazine adsorption was decreased in S‐300 (Kf = 0.96) compared with the control (S‐0) (Kf = 1.19), possibly due to the competitive adsorption of DOC with the pesticide. The Fourier‐transformed infrared analysis showed that LCM increased aliphaticity and presence of N‐containing groups and polysaccharide‐like groups in amended soils; however, these properties did not modify the atrazine interaction in the studied amended soils. Interestingly the addition of DOC to soil at the high application rate (S‐300) reduced atrazine adsorption in this rich OM Andisol despite the LCM not raising the concentration of stable organic matter. The application of high rates of liquid manure containing DOC incurs an increased risk of pesticide leaching.
Effect of Sampling Frequency on Estimates of Cumulative Nitrous Oxide Emissions
Authors: Parkin Timothy B.
Published: June 2008

It is generally recognized that soil N2O emissions can exhibit pronounced day‐to‐day variations; however, measurements of soil N2O flux with soil chambers typically are done only at discrete points in time. This study evaluated the impact of sampling frequency on the precision of cumulative N2O flux estimates calculated from field measurements. Automated chambers were deployed in a corn/soybean field and used to measure soil N2O fluxes every 6 h from 25 Feb. 2006 through 11 Oct. 2006. The chambers were located in two positions relative to the fertilizer bands—directly over a band or between fertilizer bands. Sampling frequency effects on cumulative N2O–N flux estimation were assessed using a jackknife technique where populations of N2O fluxes were constructed from the average daily fluxes measured in each chamber. These test populations were generated by selecting measured flux values at regular time intervals ranging from 1 to 21 d. It was observed that as sampling interval increased from 7 to 21 d, variances associated with cumulative flux estimates increased. At relatively frequent sampling intensities (i.e., once every 3 d) N2O–N flux estimates were within ±10% of the expected value at both sampling positions. As the time interval between sampling was increased, the deviation in estimated cumulative N2O flux increased, such that sampling once every 21 d yielded estimates within +60% and −40% of the actual cumulative N2O flux. The variance of potential fluxes associated with the between‐band positions was less than the over‐band position, indicating that the underlying temporal variability impacts the efficacy of a given sampling protocol.
Managing Biosolids Runoff Phosphorus Using Buffer Strips Enhanced with Drinking Water Treatment Residuals
Authors: Wagner D. J. , Elliott H. A. , Brandt R. C. , Jaiswal D.
Published: June 2008

Vegetated buffers strips typically have limited ability to reduce delivery of dissolved phosphorus (DP) from agricultural fields to surface waters. A field study was conducted to evaluate the ability of buffer strips enhanced with drinking water treatment residuals (WTRs) to control runoff P losses from surface‐applied biosolids characterized by high water‐extractable P (4 g kg−1). Simulated rainfall (62.4 mm h−1) was applied to grassed plots (3 m × 10.7 m including a 2.67 m downslope buffer) surface‐amended with biosolids at 102 kg P ha−1 until 30 min of runoff was collected. With buffer strips top‐dressed with WTR (20 Mg ha−1), runoff total P (TP = 2.5 mg L−1) and total DP (TDP = 1.9 mg L−1) were not statistically lower (α = 0.05) compared to plots with unamended grass buffers (TP = 2.7 mg L−1; TDP = 2.6 mg L−1). Although the applied WTR had excess capacity (Langmuir P maxima of 25 g P kg−1) to sorb all runoff P, kinetic experiments suggest that sheet flow travel time across the buffers (∼30 s) was insufficient for significant P reduction. Effective interception of dissolved P in runoff water by WTR‐enhanced buffer strips requires rapid P sorption kinetics and hydrologic flow behavior ensuring sufficient runoff residence time and WTR contact in the buffer. Substantial phosphate‐adsorbent contact opportunity may be more easily achieved by incorporating WTRs into P‐enriched soils or blending WTRs with applied P sources.
Nutrient Dynamics and Tree Growth of Silvopastoral Systems: Impact of Poultry Litter
Authors: Blazier Michael A. , Gaston Lewis A. , Clason Terry R. , Farrish Kenneth W. , Oswald Brian P. , Evans Hayden A.
Published: June 2008

Fertilizing pastures with poultry litter has led to an increased incidence of nutrient‐saturated soils, particularly on highly fertilized, well drained soils. Applying litter to silvopastures, in which loblolly pine (Pinus taeda L.) and bahiagrass (Paspalum notatum) production are integrated, may be an ecologically desirable alternative for upland soils of the southeastern USA. Integrating subterranean clover (Trifolium subterraneum) into silvopastures may enhance nutrient retention potential. This study evaluated soil nutrient dynamics, loblolly pine nutrient composition, and loblolly pine growth of an annually fertilized silvopasture on a well drained soil in response to fertilizer type, litter application rate, and subterranean clover. Three fertilizer treatments were applied annually for 4 yr: (i) 5 Mg litter ha−1 (5LIT), (ii) 10 Mg litter ha−1 (10LIT), and (iii) an inorganic N, P, K pasture blend (INO). Litter stimulated loblolly pine growth, and neither litter treatment produced soil test P concentrations above runoff potential threshold ranges. However, both litter treatments led to accumulation of several nutrients (notably P) in upper soil horizons relative to INO and unfertilized control treatments. The 10LIT treatment may have increased N and P leaching potential. Subterranean clover kept more P sequestered in the upper soil horizon and conferred some growth benefits to loblolly pine. Thus, although these silvopasture systems had a relatively high capacity for nutrient use and retention at this site, litter should be applied less frequently than in this study to reduce environmental risks.
Integrating Contributing Areas and Indexing Phosphorus Loss from Agricultural Watersheds
Authors: Sharpley Andrew N. , Kleinman Peter J. A. , Heathwaite A. Louise , Gburek William J. , Weld Jennifer L. , Folmar Gordon J.
Published: June 2008

Most states in the USA have adopted P Indexing to guide P‐based management of agricultural fields by identifying the relative risk of P loss at farm and watershed scales. To a large extent, this risk is based on hydrologic principles that frequently occurring storms can initiate surface runoff from fields. Once initiated, this hydrological pathway has a high potential to transport P to the stream. In regions where hydrologically active areas of watersheds vary in time and space, surface runoff generation by “saturation excess” has been linked to distance from stream, with larger events resulting in larger contributing distances. Thus, storm‐return period and P loss from a 39.5‐ha mixed‐land‐use watershed in Pennsylvania was evaluated to relate return‐period thresholds and distances contributing P to streams. Of 248 storm flows between 1997 and 2006, 93% had a return period of 1 yr, contributing 47% of total P (TP) export, while the largest two storms (10‐yr return period) accounted for 23% of TP export. Contributing distance thresholds for the watershed were determined (50–150 m) for a range of storm‐return periods (1−10 yr) from hydrograph analysis. By modifying storm‐return period thresholds in the P Index and thereby contributing distance, it is possible to account for greater risk of P loss during large storms. For instance, increasing return period threshold from 1 (current P indices) to 5 yr, which accounted for 67% of TP export, increased the P‐management restricted area from 20 to 58% of the watershed. An increase in impacted area relative to a decreased risk of P loss creates a management‐policy dilemma that cannot be ignored.
Improvement of Sand Filter and Constructed Wetland Design using an Environmental Decision Support System
Authors: Turon Clàudia , Comas Joaquim , Torrens Antonina , Molle Pascal , Poch Manel
Published: June 2008

With the aim of improving effluent quality of waste stabilization ponds, different designs of vertical flow constructed wetlands and intermittent sand filters were tested on an experimental full‐scale plant within the framework of a European project. The information extracted from this study was completed and updated with heuristic and bibliographic knowledge. The data and knowledge acquired were difficult to integrate into mathematical models because they involve qualitative information and expert reasoning. Therefore, it was decided to develop an environmental decision support system (EDSS‐Filter‐Design) as a tool to integrate mathematical models and knowledge‐based techniques. This paper describes the development of this support tool, emphasizing the collection of data and knowledge and representation of this information by means of mathematical equations and a rule‐based system. The developed support tool provides the main design characteristics of filters: (i) required surface, (ii) media type, and (iii) media depth. These design recommendations are based on wastewater characteristics, applied load, and required treatment level data provided by the user. The results of the EDSS‐Filter‐Design provide appropriate and useful information and guidelines on how to design filters, according to the expert criteria. The encapsulation of the information into a decision support system reduces the design period and provides a feasible, reasoned, and positively evaluated proposal.
Physical and Chemical Properties of Feedlot Pen Surfaces Located on Moderately Coarse– and Moderately Fine–Textured Soils in Southern Alberta
Authors: Miller Jim J. , Curtis Tony , Larney Francis J. , McAllister Tim A. , Olson Barry M.
Published: June 2008

Southern Alberta has the highest density of feedlot cattle in Canada, and there is a concern that leaching of water and contaminants may be greater for feedlots located on coarser‐textured than finer‐textured soils. Our objective was to determine if infiltration and leaching were greater for a 4‐yr‐old feedlot located on a moderately coarse–textured (MC) soil compared with two feedlots located on moderately fine–textured (MF) soils (5‐ and 52‐yr‐old pens). Various soil physical properties of feedlot pen surfaces were measured, including field‐saturated hydraulic conductivity (Kfs) and near‐saturated hydraulic conductivity at −0.9 and −3.9 cm water potential. Selected chemical properties of feedlot soil layers were measured, as well as the chloride content of the soil profile (0–100 cm). Mean Kfs, K(−0.9), and K(−3.9) values were not significantly (P > 0.10) greater at the MC site than the two MF sites, indicating no evidence of greater infiltration on coarser‐textured soils. In addition, mean Kfs, K(−0.9), and K(−3.9) values of soils within feedlot pens at all three sites were significantly (P ≤ 0.10) reduced by 46 to 78% compared with soil outside the pens. Depth of chloride accumulation was greatest at the 52‐yr‐old feedlot on MF soil (60–70 cm), followed by 4‐yr‐old feedlot on MC soil (40–50 cm) and 5‐yr‐old feedlot on MF soil (30–40 cm). Visual inspection determined that the black interface layer formed within 2 mo of cattle stocking at all three sites.
Greenhouse Gas Emissions from Two Soils Receiving Nitrogen Fertilizer and Swine Manure Slurry
Authors: Jarecki Marek K. , Parkin Timothy B. , Chan Alvarus S. K. , Hatfield Jerry L. , Jones Raymond
Published: June 2008

The interactive effects of soil texture and type of N fertility (i.e., manure vs. commercial N fertilizer) on N2O and CH4 emissions have not been well established. This study was conducted to assess the impact of soil type and N fertility on greenhouse gas fluxes (N2O, CH4, and CO2) from the soil surface. The soils used were a sandy loam (789 g kg−1 sand and 138 g kg−1 clay) and a clay soil (216 g kg−1 sand, and 415 g kg−1 clay). Chamber experiments were conducted using plastic buckets as the experimental units. The treatments applied to each soil type were: (i) control (no added N), (ii) urea‐ammonium nitrate (UAN), and (iii) liquid swine manure slurry. Greenhouse gas fluxes were measured over 8 weeks. Within the UAN and swine manure treatments both N2O and CH4 emissions were greater in the sandy loam than in the clay soil. In the sandy loam soil N2O emissions were significantly different among all N treatments, but in the clay soil only the manure treatment had significantly higher N2O emissions. It is thought that the major differences between the two soils controlling both N2O and CH4 emissions were cation exchange capacity (CEC) and percent water‐filled pore space (%WFPS). We speculate that the higher CEC in the clay soil reduced N availability through increased adsorption of NH4+ compared to the sandy loam soil. In addition the higher average %WFPS in the sandy loam may have favored higher denitrification and CH4 production than in the clay soil.