bluuebunny/crossref_metadata_2025 huggingface dataset:
Phosphorus in Soils of Temperate Forests: Linkages to Acidity and Aluminum
Authors: SanClements Michael D. , Fernandez Ivan J. , Norton Stephen A.
Published: October 2010

We used P fractionation techniques to study the accumulation, mobilization, and availability of soil P in six watersheds of the eastern United States and Europe, two of which included paired long‐term acidification experiments. Although total soil P concentrations varied widely among these watersheds, the proportions of P fractions were relatively uniform. The mean for the P fraction operationally defined as being associated with Al in the reference watersheds was 71% of total extractable P (SE ≤ 1%). Experimental whole‐watershed acidification resulted in significant depletion of Al‐P concentrations from the upper mineral soil in treated watersheds due to the dissolution of Al hydroxide by acidic solutions traveling along shallow flow paths. Acidic soil solutions mobilize both Al and P, leading to P depletion from the Al‐P fraction in the mineral soils. Across this suite of watersheds, lower pH appears to decrease Al/P ratios in the Al‐P fraction of these mineral soils through changes in Al solubility. Biocycling in these forests can play a critical role in linking subsurface mineral soil P to surface O horizon available P. In this study, sites with the lowest mineral subsoil Al/P ratios generally had the lowest mineral soil pH values and the highest O horizon available P concentrations. The net effect was to leave subsoil P more bioavailable at the lower pH values because of a lower Al/P ratio in the mineral subsoil at the pH range of 3.1 to 4.6 found in this study. These results suggest that changes in soil acidity due to management, air pollutants, or pedogenesis could shift P availability by altering acidity and the Al/P balance.
Drip Irrigation Water Distribution Patterns: Effects of Emitter Rate, Pulsing, and Antecedent Water
Authors: Skaggs Todd H. , Trout Thomas J. , Rothfuss Youri
Published: October 2010

Drip irrigation is more effective and less expensive if a large amount of soil can be wetted with each emitter without losing water or nutrients below the root zone. The distance that water spreads horizontally from a drip line and the volume of soil wetted are limiting factors that determine the spacing and number of drip lines and emitters, the frequency of irrigation, and thus the cost of irrigation. We used numerical simulations and field trials to investigate the effects of application rate, pulsed water application, and antecedent water content on the spreading of water from drip emitters. Simulation results showed that pulsing and lower application rates produced minor increases in horizontal spreading at the end of water application. The small increases were primarily due to longer irrigation times, however, and not to flow phenomena associated with pulsing or low application rates. Moreover, the small increases mostly disappeared after the infiltrated water had redistributed for a period of 24 h. Field trials confirmed the simulation findings, with no statistically significant difference in wetting being found among five water application treatments involving pulsed applications and varying application rates. The simulations showed that higher antecedent water content increases water spreading from drip irrigation systems, but the increases were greater in the vertical direction than in the horizontal, an undesirable outcome if crop roots are shallow or groundwater contamination is a concern. Overall, soil texture (hydraulic properties) and antecedent water content largely determine the spreading and distribution of a given water application, with pulsing and flow rate having very little impact.
Seventy‐Four Years of Calcium Loss from Forest Soils of the Adirondack Mountains, New York
Authors: Bedison James E. , Johnson Arthur H.
Published: October 2010

In 2005/6, we conducted a remeasurement investigation of organic and mineral horizon Ca at 54 sites in forests of the Adirondack Mountains, New York. This network of plots represents northern hardwood, pine‐dominated, and high‐elevation spruce–fir stands typical of this region. Soil Ca had been measured at these sites twice (1930–1932 and 1984) in the previous 74 yr. Consistent with the original methods, we used measurements of dilute HCl (0.2 mol L−1) extractable Ca to make comparisons among the 1930 to 1932, 1984, and 2005/6 samples. Between 1932 and 2005/6, median HCl‐extractable Ca content decreased significantly (78%) in organic horizons and in the whole profile (organic + mineral horizons, 64%), although significant decreases in mineral soil Ca content were confined to the upper 20 cm. Moreover, significant decreases in organic horizon (−1.5% yr−1), mineral horizon (−1.0% yr−1), and whole profile (−1.5% yr−1) Ca content between 1984 and 2005/6 indicated that Ca depletion has been sustained in recent decades. When stratified by forest type, there were significant decreases in extractable Ca concentrations and content in organic horizons and in the whole profile for all forest types between 1932 and 2005/6, although decreases between 1984 and 2005/6 were not necessarily significant. Overall, the rate of median whole‐profile Ca depletion (∼13.6 kg ha−1 yr−1) was similar during all sampling intervals, suggesting that the combined Ca inputs from atmospheric deposition and mineral weathering have not kept pace with leaching and sequestration in biomass during much of the 20th and early 21st centuries in these plots.
Ensemble Approach to Provide Uncertainty Estimates of Soil Bulk Density
Authors: Nemes A. , Quebedeaux B. , Timlin D. J.
Published: October 2010

Large scale environmental impact studies typically involve the use of simulation models and require a variety of inputs, some of which may need to be estimated in absence of adequate measured data. An important input, soil bulk density (Db) affects conditions for soil aeration, solute transport, and storage as well as the outcome of soil C stock calculations. Correct representation of Db in simulation studies is essential since any bias or uncertainty will propagate through a variety of processes and time steps. We used the U.S.‐wide NRCS National Soil Survey Characterization (NSSC) database of point measurements and the ‘k‐nearest neighbor’ (k‐NN) pattern recognition algorithm combined with random resampling without replacement to estimate Db and its uncertainty. Soil particle‐size distribution and organic C content were utilized as inputs and soil taxonomy classification, sample depth, and soil horizon notation were tested as optional grouping and limiting factors to the calibration (reference) data. We obtained an overall root‐mean‐squared error (RMSE) of 0.17 g cm−3 and mean error (ME) of 0.01 g cm−3 Grouping samples by taxonomic classification proved to be advantageous, while limiting samples by depth helped avoid depth‐specific bias in the estimations. Grouping samples by horizon notation did not yield significant improvement due to the great variability of bulk density within horizons of the same notation. Varying the proportion of data used in the resampled data subsets can be used to establish greater or lesser degree of confidence in mean estimates without affecting those mean estimates. Simulation based environmental impact and risk assessment studies can be direct beneficiaries of data with characterized uncertainty.
Utilization of Poultry Manure Phosphorus for Corn Production
Authors: Kaiser Daniel E. , Mallarino Antonio P. , Sawyer J. E.
Published: October 2010

There is uncertainty about the need for supplemental P fertilization after applying poultry manure for corn (Zea mays L.). This study evaluated the effects of manure and fertilizer P on corn by establishing 17 on‐farm trials in Iowa. Manure from broilers, egg layers (Gallus gallus domesticus), or turkeys (Melleagris gollopavo) was used at each site. Replicated treatments were the combinations of three manure rates (0, 53, and 104 kg P ha−1 on average across sites) and four triple superphosphate rates (0–75 kg P ha−1). Initial Olsen P (15‐cm depth) was 5 to 23 mg P kg−1 across sites. Uniform rates of 168 kg N ha−1 and 56 to 112 kg K ha−1 were applied. Measurements were early plant dry weight (DW); P concentration and P uptake (V5–V6 stage); and grain yield, P concentration, and P removal. Increases in plant DW and P uptake were unrelated to soil‐test P, were more frequent for manure, and only one site that was responsive (P ≤ 0.10) to fertilizer was not responsive to manure. Phosphorus fertilization in addition to manure increased plant DW at four sites and P uptake at eight sites. Both P sources increased grain yield at eight sites with <15 mg Olsen P kg−1, only manure increased it at another site, and supplemental fertilization did not increase yield at any site. The results provided no evidence for lower P availability of poultry manure P than fertilizer P for corn yield and showed no need for supplemental P fertilization at prevailing manure rates used by farmers.
Evaluation of Two Ground‐Based Active Crop Canopy Sensors in Maize: Growth Stage, Row Spacing, and Sensor Movement Speed
Authors: Shaver T. M. , Khosla R. , Westfall D. G.
Published: October 2010

Precision agriculture research has been directed toward enhancing the efficiency of N inputs by quantifying in‐field variability. Remotely sensed indices such as normalized difference vegetation index (NDVI) can determine in‐field N variability in maize (Zea mays L.). One method of determining NDVI is through the use of ground‐based active crop canopy sensors. Several crop canopy sensors determine NDVI, however, climatic and management variables may affect NDVI readings. Our objectives were to compare two ground‐based active crop canopy sensors (Crop Circle amber and GreenSeeker red) across plant growth stage, wind, crop row spacing, sensor movement speed, and N fertilizer rate under greenhouse conditions. Results show that wind had no effect on the NDVI readings of either sensor. Nitrogen rate and growth stage did affect the NDVI of both sensors with NDVI values generally increasing with increased N rate and advancing growth stage. For both sensors the V8 NDVI r2 with N rate were lower than those observed at V10 and V12. However, the GreenSeeker (red sensor) had much lower r2 values at V8 than the Crop Circle (amber sensor). Sensor speed had an effect on red sensor NDVI values while the amber sensor was not affected by sensor movement speed. The amber and red sensors distinguish plant N status and growth stage differences in maize in a greenhouse environment. However, the red sensor had more variability in NDVI readings and was affected by movement speed. The amber sensor shows no such limitations and therefore performed best under greenhouse conditions.
Synergistic Dissolution of Manganese Oxides as Promoted by Siderophores and Small Organic Acids
Authors: Saal Lauren B. , Duckworth Owen W.
Published: October 2010

Recent studies have revealed that siderophores, biogenic chelating agents that strongly complex Fe(III) and other hard metals, may function in concert with low‐molecular‐mass organic acids (LMMOAs) to facilitate Fe (hydr)oxide dissolution via synergistic reactions. The siderophore desferrioxamine B (DFOB) may also participate in a number of chemical reactions at Mn (hydr)oxide surfaces. The goal of this study was to determine the rates and products of δ‐MnO2, a layer type Mn(IV) oxide, dissolution as promoted by LMMOA–DFOB mixtures. As with Fe (hydr)oxides, the rate of DFOB‐promoted dissolution of δ‐MnO2 is strongly influenced by the presence of the LMMOAs citrate and oxalate. In the presence of DFOB, citrate increases the dissolution rate relative to the sum of dissolution rates from corresponding single‐ligand systems by promoting both Mn(III)HDFOB+ complex formation and Mn(II) production in a pH‐dependent mechanism. In contrast, oxalate–DFOB mixtures produce predominantly Mn(II), with rates enhanced up to threefold from the sum of dissolution rates in single‐ligand systems at acidic pH values. We investigated possible mechanisms to describe this synergistic dissolution processes by building on observations of single‐ligand systems. These results suggest that biological exudation of LMMOAs in conjunction with siderophores may allow the selection of dissolution products, including regulation of the formation of potentially reactive aqueous Mn(III) complexes.
Effect of Tillage on the Hydrology of a Claypan Soil in Kansas
Authors: Buckley M.E. , Kluitenberg G.J. , Sweeney D.W. , Kelley K.W. , Stone L.R.
Published: October 2010

The midwestern United States has >4 million ha of claypan soils. These soils often require special management because of poor infiltration, drainage, and available water supply. This study was conducted to quantify the hydrologic balance of a claypan soil and determine the effect of tillage on water balance components. It was part of an ongoing project in Labette County, Kansas, in which no‐till and chisel tillage plots had been maintained since 1995. A sorghum [Sorghum bicolor (L.) Moench]–soybean [Glycine max (L.) Merr.] rotation was initiated in 2003, with both crops grown each year in a randomized complete block design. The plots in sorghum were instrumented to measure water content throughout the profile. Precipitation and evapotranspiration (ET) were determined at the field scale. Soil hydraulic properties and water content data were used to estimate drainage. Runoff was determined as the residual in this water balance. Evaporation from chisel tillage was up to 1 mm d−1 greater than that from no‐till during the early season. This resulted in differences in surface water content and runoff. These effects were limited to the early season, however, so that the water balance for the full growing season was not significantly affected by tillage. Drainage from the claypan soil was negligible. The 2006 crop year had 23.5 cm of ET, a value greater than the in‐season precipitation. The 2007 crop year had 33.5 cm of ET, a value less than the in‐season precipitation. With limited drainage and storage in the claypan, 37.5 cm of runoff occurred in 2007.
Butachlor Sorption in Organically Rich Soil Particles
Authors: Liu Zhongzhen , Ding Na , Hayat Tahir , He Yan , Xu Jianming , Wang Haizhen
Published: October 2010

The herbicide butachlor [N‐(butoxymethyl)‐2‐chloro‐N‐(2,6‐diethylphenyl)acetamide] is a pre‐emergence herbicide belonging to the chloroacetanilide group used widely to control grasses in Asian countries. Butachlor has toxicity to aquatic organisms and earthworms and can induce apoptosis in mammalian cells. This study used a batch equilibration method to investigate butachlor sorption by different size organomineral fractions of a black soil. About 60 to 70% of butachlor was adsorbed on the clay size fraction, 30 to 40% on the silt fraction, and <0.3% by the fine sand fraction. For the clay fraction, the nonlinearity of adsorption was significant in the low equilibrium concentration range. For the silt and fine sand fractions, the isotherms were near linear across the concentration range studied. Butachlor adsorption on a clay fraction treated with H2O2 showed that the degree of nonlinearity became smaller, and the value of the normalized sorption coefficient for organic C (Koc) was much higher than that of the untreated clay fraction. Mineral colloids might have a dual function in the butachlor adsorption process. For an adsorbent with a very low soil organic matter (SOM) content, mineral colloids could enhance butachlor adsorption because of their high exposed mineral surface, which would result in higher Koc values. For an adsorbent with a high SOM content, mineral colloids might weaken the SOM partition function because of their strong association with and coating of SOM, which would result in lower Koc values. These results are useful to better understand the adsorption mechanism of anthropogenic organics in different components and size fractions of soils.
Surface Soil Changes during Twelve Years of Pasture Management in the Southern Piedmont USA
Authors: Franzluebbers Alan J. , Stuedemann John A.
Published: October 2010

Surface soil characteristics are of key importance in assessing the sustainability of agricultural management systems. We evaluated the factorial combination of nutrient source (inorganic, mixed organic + inorganic, and organic as broiler litter) and forage utilization (unharvested, low and high cattle grazing pressure, and hayed) on soil organic matter during 12 yr of pasture management on a Typic Kanhapludult in Georgia. Nutrient source had very little effect on bulk density, soil organic C (SOC), and total soil N (TSN). Forage utilization greatly affected all soil properties, more so nearest the surface. For example, SOC at a depth of 0 to 3 cm under low grazing pressure was 47.6 g kg−1 and under haying was 28.8 g kg−1 (P < 0.001), while at 3 to 6 cm it was 20.1 and 14.9 g kg−1, respectively (P = 0.04), and at 6 to 12 cm it was 12.7 and 11.0 g kg−1, respectively (P = 0.59). Soil bulk density was inversely related to SOC. Total SOC (0–20 cm) plus surface residue C was 3.6 ± 3.6 Mg C ha−1 greater (mean ± standard deviation among six nutrient source × forage utilization comparisons) in the zone nearest shade and water sources than farther away. Sequestration of TSN in the surface 6 cm averaged 8 ± 8 kg N ha−1 yr−1 (mean ± standard deviation among three nutrient source comparisons) when hayed, 31 ± 15 kg N ha−1 yr−1 when left unharvested, and 74 ± 5 kg N ha−1 yr−1 when grazed by cattle with either low or high grazing pressure. These results indicate the large potential of well‐managed grazing systems to improve the quality and functioning of soils in the southeastern United States.
Plowing a Poorly Drained Grassland Reduced Soil Respiration
Authors: MacDonald J. Douglas , Angers Denis A. , Rochette Philippe , Chantigny Martin H. , Royer Isabelle , Gasser Marc-Olivier
Published: October 2010

Managed grasslands are a predominant land use in northern temperate regions. They are often on poorly drained soils and contain large stocks of soil organic carbon (SOC). It is important to understand C dynamics in grasslands to better assess their role in regional C budgets. Two adjacent grassland plots, one amended with 100 m3 ha−1 of liquid swine manure (LSM) annually since 1978, and another unamended were killed by glyphosate in the autumn or (i) left with vegetation intact. Those killed were either (ii) left as an undisturbed chemical fallow, (iii) plowed by full‐inversion tillage (FIT) in the autumn, or (iv) in the spring. Following the autumn plowing, we monitored CO2 emissions from the fallow soil surface, CO2 concentrations in the soil profile, soil temperature, and soil water content for 1 yr. Changes in soil aggregation, the light fraction organic matter, and microbial biomass were also monitored. Plowing decreased the total microbial biomass on average by 27 g C m−2, the quantity of water‐stable aggregates by 7 to 12% and with it the concentration of light fraction organic matter. Respiration was also reduced by 142 g CO2‐C m−2 by autumn‐FIT and 175 g CO2‐C m−2 by spring‐FIT on unamended soils, and 90 g CO2‐C m−2 by autumn‐FIT and 98 g CO2‐C m−2 by spring‐FIT on amended soils. Regression analyses suggested that reductions in CO2 emissions were due to the placement of surface SOC at depth where soil temperature and oxygen availability were attenuated. In these soils, the cool humid conditions at depth in the soil profile may act to counter‐balance the physical effects of tillage thereby preserving C deep in the soil profile. Effective calculation of C budgets and changes in SOC stocks depends on the ability to reproduce the interaction between climate, soil type, land use, and management action. A more complete understanding of the effect of management actions that modify the vertical distribution of biogeochemical (particularly organic C) and environmental parameters on soil respiration in poorly drained soils is required.
Influence of Constant and Fluctuating Water Contents on Nitrous Oxide Emissions from Soils under Varying Crop Rotations
Authors: Guo Xiaobin , Drury Craig F. , Yang Xueming , Zhang Renduo
Published: October 2010

Soil water contents and cropping history influence soil organic matter decomposition, N cycling, and NO3− losses. However, soil water content fluctuates within and between seasons, which adds complexity to these biochemical processes. The impacts of constant soil water contents (30, 45, 60, 75, and 90% water‐filled pore space, WFPS), wet–dry (WD) cycles (90–30% WFPS), and crop rotation (monoculture corn [Zea mays L.], a 2‐yr corn–soybean [Glycine max (L.) Merr.] rotation, or a 3‐yr corn–soybean–winter wheat [Triticum aestivum L.] rotation) on N2O emissions, inorganic N, and denitrification enzyme activity (DEA) were investigated using repacked soil cores incubated for 50 d. The 30% WFPS treatment resulted in a net accumulation of inorganic N after 50 d. In the constant‐WFPS treatments, increasing water content increased DEA, reduced soil inorganic N, and enhanced N2O emissions. When water contents fluctuated in five WD cycles, there was a considerable decrease in NO3− concentrations, high DEA activity, but low N2O emissions, which were similar to the emissions for the 30% WFPS treatment. Hence, fluctuating soil water content provided a soil environment that may have stimulated N2O reduction to N2 or other microbial processes such as NO3− immobilization. At the wettest WFPS (90% WFPS), N2O emissions were greater under monoculture corn than the 3‐yr rotation, which is consistent with the larger decreases in inorganic N and higher DEA levels. Nitrous oxide emissions accounted for between 7.5 and 27.4% of NO3− loss when soils were incubated at 90% WFPS but only 3.86 to 5.12% with the WD cycles. Nitrous oxide emissions were found to be influenced by soil water content to a greater extent than crop rotation.
Sensitivity of Capacitance Soil Moisture Sensors to Nitrate Ions in Soil Solution
Authors: Chighladze G. , Kaleita A. , Birrell S.
Published: October 2010

Capacitance type sensors have been widely used to monitor soil water content and salinity, but little is known about their response to specific ions in soil solution. The goal of this laboratory study was to investigate the sensitivity of two capacitance probes, ECH2O EC‐5 and EC‐10, to NO3 concentration in soil solutions, as well as to understand the differences in sensor response to the presence of other ions in the solutions. Forty‐five uniformly packed soil samples were prepared using a homogenized loam soil wetted to five volumetric water contents (VWC) with nine solutions containing different concentrations of NO3−, Cl−, or both. A two‐stage analysis of the normalized data revealed that ion type and concentration had a significant effect (P ∼ 0.01) only for the response of the EC‐10 probes operating at a frequency of 5 MHz. The response of the EC‐5 probes, operating at 70 MHz, was mainly explained by changes in VWC. Multiple linear regression models fitted to the EC‐10 response to individual solutions showed that concentration had a statistically significant predictive value only for samples wetted with NO3 solutions when temperature was incorporated in the model. The study confirmed that capacitance probes operating at a relatively low frequency of 5 MHz are more sensitive to changes in NO3 concentration than in Cl. We attributed this effect to the difference in ion mass that manifests through an increase in conductivity at ion‐specific frequency. Additional experimental work is needed, however, to accurately define optimal frequencies for measuring ion‐induced effects on dielectric measurement and to quantify interrelations between them.
Labile Organic Matter, Aggregates, and Stratification Ratios in a Semiarid Vineyard with Cover Crops
Authors: Peregrina F. , Larrieta C. , Ibáñez S. , García-Escudero E.
Published: October 2010

Under semiarid Mediterranean climatic conditions, scarce attention has been given to the utilization of permanent cover crops (PCCs) in vineyard agroecosystems to increase soil organic C (SOC) and to improve the soil quality. We evaluated the feasibility of two permanent cover crops (resident vegetation, RV, and ‘Aurora gold’ blue fescue [Festuca longifoliaThuill.] vegetation, FV) to increase SOC and to improve the soil quality with respect to conventional tillage in a semiarid vineyard. We studied the influence of these management practices on the labile organic matter fractions (particulate organic C [POC], potentially mineralizable N [PMN], and water‐soluble C [WSC]), on the water aggregate stability (WAS) and on the stratification ratios (SRs) of these soil attributes. The field experiment was conducted on a fine‐loamy, mixed, thermic Typic Haploxerept soil in a vineyard located in the La Rioja region (northeast Spain). Soil samples were collected from four soil layers (at depths of 0–2.5, 2.5–5, 5–15, and 15–25 cm) during June 2008, 4 yr after cover crop establishment. The SOC content, POC, WSC, PMN, and WAS were measured. At a depth of 0 to 2.5 cm, the cover crops increased SOC, POC, WSC, PMN, and WAS. The C sequestration rates for RV and FV were 1.34 ± 0.31 and 1.52 ± 0.70 Mg ha−1yr−1, respectively. Regression analyses indicated positive strong correlations among all parameters monitored. The SRs of the SOC, POC, and PMN were >2 in all depth ratios calculated and therefore were efficient indicators of the soil quality improvement caused by the PCCs. In a semiarid Mediterranean vineyard, a PCC has proven to be an effective strategy to enhance the SOC and to improve the soil quality in the short term.
Quantitative Analysis of Soil Organic Carbon Using Laser‐Induced Breakdown Spectroscopy: An Improved Method
Authors: Glumac Nick G. , Dong Willie K. , Jarrell Wesley M.
Published: October 2010

Standard laser‐induced breakdown spectroscopy (LIBS) offers a potentially rapid, accurate, field‐portable, and low‐cost technique for the measurement of C content in soil samples. Neutral and singly ionized Fe lines form significant interferences, however, that can compromise the LIBS C measurement. In this study, the 247.8‐nm line of atomic C (C I) was examined in detail to assess the effect of potential elemental interferences. These interferences and their spectral and temporal signatures were evaluated using control graphite and Fe oxide samples. A combination of high dispersion and appropriate time gating of the LIBS signal was found to generate very high signal/noise ratio spectra using low laser powers and therefore, allowed accurate determination of the C content down to the subpercent level in the presence of Fe interferences. Although the contribution of one singly ionized Fe line cannot be entirely eliminated, a method to quantitatively assess the contribution of this line was developed. The new technique was tested on soil samples with organic C content in the 0.5 to 3% (w/w) range, and a strong correlation of the LIBS C signal with measurements made by the thermal oxidation, dry combustion method was observed. The findings reaffirm the utility of standard LIBS for rapid and accurate laboratory measurement of soil C and the potential use of standard LIBS with further study and development for assessing soil C in situ.
Influence of Initial Water Content on the Wettability of Autoclaved Soils
Authors: Urbanek Emilia , Bodi Merche , Doerr Stefan H. , Shakesby Richard A.
Published: October 2010

Autoclaving is a commonly used practice to destroy microbial activity in soils but is thought to have a limited effect on other soil properties. Small changes in chemical composition have been reported, but there have been no previous reports of any alteration of physical properties. This study, however, showed that autoclaving can cause a major change in soil hydraulic properties. For samples with intermediate water contents (10–35% v/v), it caused severe or extreme water repellency in three of four soil types tested, although no effect for initially low or high water contents was found. These findings have important implications for any experimental work involving soil autoclaving as a pretreatment procedure but could also be used for generating otherwise similar samples differing only in terms of wettability.
Private Standards in the Climate Regime: The Greenhouse Gas Protocol
Authors: Green Jessica F.
Published: October 2010

This paper seeks to explain the success of two NGOs in creating standards for calculating and reporting greenhouse gas (GHG) emissions at the level of an entire company. These emissions accounting standards, called the Greenhouse Gas Protocol, have been widely adopted by multinational firms, emissions reporting registries, and even an emissions trading scheme. The paper traces the widespread adoption of the standards, and then offers an explanation for this successful instance of private regulation. It presents a supply and demand model of private entrepreneurial authority—where private actors project authority without delegation by states. The two NGOs were successful rule-makers because they were able meet a demand for three benefits to potential users of the standard: reduced transaction costs, first-mover advantage, and an opportunity to burnish their reputation as environmental leaders. The paper also explains the supply of private authority—that is, why we see entrepreneurial authority rather than delegation by states. The disagreement among developed countries on the appropriate role for emissions trading in the climate regime delayed action on developing firm-level accounting methodologies. Moreover, the relative weakness of the focal institution in the climate regime—the climate change Secretariat—meant that there was no obvious international organization to take up the task of creating new measurement tools.
Transnational Private Regulation in Practice: The Limits of Forest and Labor Standards Certification in Indonesia
Authors: Bartley Tim
Published: October 2010

Systems for certifying sustainable resource use and decent labor conditions have become prominent modes of private regulation at the transnational level. But serious questions remain about how these global standards are put into practice in particular places, especially in developing countries. Drawing on fieldwork in Indonesia, this paper examines the growth of certification of sustainable forestry (e.g., through the Forest Stewardship Council) and certification of decent labor conditions in factories (e.g., through Social Accountability International). Based on the controversy that surrounded both sweatshops and deforestation in Indonesia, and the export dependence of both the apparel/footwear and forest products sectors, these would appear to be prime candidates for the application of certification. Yet in both sectors, the growth of multi-stakeholder certification has been limited. Furthermore, private regulation in Indonesia has taken somewhat divergent paths in these two sectors, which shapes certification's significance at the point of production. The paper examines how the socio-legal context of certification, the character of supply chain relationships, and possible differences in the politics of labor and the environment can help to explain these patterns and contribute to a richer sense of private regulation's “on the ground” manifestations.
The Search for Credible Information in Social and Environmental Global Governance: The Kosher Label
Authors: Starobin Shana , Weinthal Erika
Published: October 2010

Hundreds of “eco-labels” and “social labels” exist for consumer products. These labels claim to provide information about characteristics of these products, which consumers cannot directly observe but which many of them consider desirable, such as low environmental impact, good treatment of workers during production, and relatively high prices paid to the local producers of ingredients from developing countries. Third-party certifiers are supposed to solve the well-known problem that a producer's unilateral declarations lack credibility, given the producer's conflict of interest and the information asymmetries between producer and consumer. Much of the literature on global private regulation—through standards for environmental sustainability, corporate social responsibility, among others—assumes that third-party certification works (i.e., overcomes the problems of producer self-declaration). But closer inspection shows that many third-party certifiers lack credibility. This article examines why some third party certifiers are more credible than others. In doing so, we elucidate the ways in which social capital and trust bolster third party certifiers' credibility. The empirical analysis focuses primarily on Kosher food labels within the global food supply chain. We then explore the consequences of the credibility paradox for other third party certified labels that promote social and environmental values.
Private-Public Interaction in Global Governance: The Case of Transnational Commercial Arbitration
Authors: Whytock Christopher A.
Published: October 2010

Scholars of international relations and global governance are increasingly interested in the transnational commercial arbitration system. So far, they have tended to characterize the system as a form of private global governance. However, using a combination of empirical and legal analysis, this article draws attention to the critical role of the state in the transnational commercial arbitration system, and shows that both rule-making and enforcement in the system depend largely on interactions between private and public actors. By treating arbitration as a form of private governance, scholars run the risk of obscuring these interactions and hindering their understanding of how transnational economic activity is governed. This article therefore argues for a modest reorientation of global governance scholarship on transnational commercial arbitration in a direction that focuses more closely on private-public interaction. More broadly, this article suggests that understanding interactions between private and public actors is a key to understanding global governance in general, and it raises doubts about the analytical desirability of a sharp distinction between private and public forms of global governance.
Continuous Flow Peritoneal Dialysis
Authors: Raaijmakers Renske , Schröder Cornelis H. , Gajjar Priya , Argent Andrew , Nourse Peter
Published: October 2010

Background and objectives

Acute renal failure can be treated with different dialysis modalities, depending on patient characteristics and hospital resources. Peritoneal dialysis (PD) can be first choice in situations like hypotension, disturbed coagulation, or difficult venous access. The main disadvantage of PD is the relatively limited efficacy. The aim of this study was to investigate whether continuous flow peritoneal dialysis (CFPD) is a more effective treatment than conventional PD in acute renal failure.

Design, setting, participants, & measurements

A pilot study was performed at The Red Cross University Hospital in Cape Town in six patients. Patients were treated with both CFPD and conventional PD for 8 to 16 hours. CFPD was performed with two bedside-placed catheters. After initial filling, dialysate flow rate (100 ml/1.73 m2 per minute) was maintained with an adapted continuous venovenous hemofiltration machine. Ultrafiltration flow rate was set at 2.5 ml/1.73 m2 per minute.

Results

Mean ultrafiltration was 0.20 ml/1.73 m2 per minute with conventional PD versus 1.8 ml/1.73 m2 per minute with CFPD. Mean clearances of urea and creatinine were 5.0 and 7.6 ml/1.73 m2 per minute with conventional PD versus 15.0 and 28.8 ml/1.73 m2 per minute with CFPD, respectively. No complications occurred.

Conclusions

In this first report of CFPD in six pediatric patients with acute renal failure, CFPD was on average three to five times more effective for urea and creatinine clearance and ultrafiltration than conventional PD, without any complications observed. CFPD has the ability to improve therapy for acute renal failure .
Effects of Dietary Phosphate and Calcium Intake on Fibroblast Growth Factor-23
Authors: Vervloet Marc G. , van Ittersum Frans J. , Büttler Rahel M. , Heijboer Annemieke C. , Blankenstein Marinus A. , ter Wee Piet M.
Published: October 2010

Background and objectives

Little is known about the influence of dietary phosphate intake on fibroblast growth factor-23 (FGF23) and its subsequent effects on vitamin D levels. This study addresses changes in intact FGF23 (iFGF23) and C-terminal FGF23 (cFGF23), phosphaturia, and levels of vitamin D on high and low phosphate and calcium intake.

Design, setting, participants, & measurements

Ten healthy subjects adhered to a diet low or high in phosphate and calcium content for 36 hours each with a 1-week interval during which subjects adhered to their usual diet. Serum phosphate, calcium, vitamin D metabolites, parathyroid hormone (PTH), and FGF23 levels (cFGF23 and iFGF23) were measured several times a day. Phosphate, calcium, and creatinine excretion was measured in 24-hour urine on all study days.

Results

Serum phosphate levels and urinary phosphate increased during high dietary phosphate intake (from 1.11 to 1.32 mmol/L, P < 0.0001 and 21.6 to 28.8 mmol/d, P = 0.0005, respectively). FGF23 serum levels increased during high dietary phosphate/calcium intake (cFGF23 from 60 to 72 RU/ml, P < 0.001; iFGF23 from 33 to 37 ng/L, P = 0.003), whereas PTH declined. 1,25-Dihydroxyvitamin D (1,25D) showed an inverse relation with FGF23.

Conclusions

Variation in dietary phosphate and calcium intake induces changes in FGF23 (on top of a circadian rhythm) and 1,25D blood levels as well as in urinary phosphate excretion. These changes are detectable the day after the change in the phosphate content of meals. Higher FGF23 levels are associated with phosphaturia and a decline in 1,25D levels.
The Association between Abnormal Birth History and Growth in Children with CKD
Authors: Greenbaum Larry A. , Muñoz Alvaro , Schneider Michael F. , Kaskel Frederick J. , Askenazi David J. , Jenkins Randall , Hotchkiss Hilary , Moxey-Mims Marva , Furth Susan L. , Warady Bradley A.
Published: October 2010

Background and objectives

Poor linear growth is a well described complication of chronic kidney disease (CKD). This study evaluated whether abnormal birth history defined by low birth weight (LBW; <2500 g), prematurity (gestational age <36 weeks), small for gestational age (SGA; birth weight <10th percentile for gestational age), or intensive care unit (ICU) at birth were risk factors for poor growth outcomes in children with CKD.

Design, setting, participants, & measurements

Growth outcomes were quantified by age-sex-specific height and weight z-scores during 1393 visits from 426 participants of the Chronic Kidney Disease in Children Study, an observational cohort of children with CKD. Median baseline GFR was 42.9 ml/min per 1.73 m2, 21% had a glomerular diagnosis, and 52% had CKD for ≥90% of their lifetime.

Results

A high prevalence of LBW (17%), SGA (14%), prematurity (12%), and ICU after delivery (40%) was observed. Multivariate analyses demonstrated a negative effect of LBW (−0.43 ± 0.14; P < 0.01 for height and −0.37 ± 0.16; P = 0.02 for weight) and of SGA (−0.29 ± 0.16; P = 0.07 for height and −0.41 ± 0.19; P = 0.03 for weight) on current height and weight. In children with glomerular versus nonglomerular diagnoses, the effect of SGA (−1.08 versus −0.18; P = 0.029) on attained weight was more pronounced in children with a glomerular diagnosis.

Conclusions

LBW and SGA are novel risk factors for short stature and lower weight percentiles in children with mild to moderate CKD independent of kidney function.
The Emerging Relationship Between Regenerative Medicine and Physical Therapeutics
Authors: Ambrosio Fabrisia , Wolf Steven L. , Delitto Anthony , Fitzgerald G. Kelley , Badylak Stephen F. , Boninger Michael L. , Russell Alan J.
Published: October 2010

Dramatic changes in the health care landscape over the next few decades undoubtedly will affect rehabilitation specialists' practice. In the multidisciplinary field of regenerative medicine, cell, tissue, or organ substitutes are used to enhance the healing potential of the body. Given that the restoration of normal functioning of injured or diseased tissues is expected to be the ultimate goal of these therapies, the future of regenerative medicine is, undeniably, tightly intertwined with that of rehabilitation. Rehabilitation specialists not only must be aware of cutting-edge medical advances as they relate to regenerative medicine but also must work closely with basic scientists to guide the development of clinically relevant protocols. The purposes of this article are to provide a current perspective on biological approaches to the management of musculoskeletal disorders and to highlight the needed integration of physical therapeutics with regenerative medicine.
Construct Validity of the Assessment of Balance in Children Who Are Developing Typically and in Children With Hearing Impairments
Authors: De Kegel Alexandra , Dhooge Inge , Peersman Wim , Rijckaert Johan , Baetens Tina , Cambier Dirk , Van Waelvelde Hilde
Published: October 2010

Background

Children with hearing impairments have a higher risk for deficits in balance and gross motor skills compared with children who are developing typically. As balance is a fundamental ability for the motor development of children, a valid and reliable assessment to identify weaknesses in balance is crucial.

Objective

The purpose of this study was to investigate the construct validity of posturography and clinical balance tests in children with hearing impairments and in children who are developing typically.

Methods

The study involved 53 children with typical development and 23 children with hearing impairments who were between 6 and 12 years of age and without neuromotor or orthopedic disorders. All participants completed 3 posturography tests (modified Clinical Test of Sensory Interaction of Balance [mCTSIB], unilateral stance, and tandem stance) and 4 clinical balance tests (one-leg stance with eyes open and with eyes closed, balance beam walking, and one-leg hopping).

Results

Three conditions of the mCTSIB, unilateral stance, and 2 clinical balance tests were able to distinguish significantly between the 2 groups. Children with hearing impairments showed more difficulties in balance tasks compared with children who were developing typically when 1 or 2 types of sensory information were eliminated or disturbed. The study showed only low to moderate correlations among the different methods of evaluating balance.

Conclusions

Clinical balance tests and posturography offer different but complementary information. An assessment protocol for balance consisting of posturography and clinical balance tasks is proposed. Static and dynamic balance abilities could not be differentiated and seem not to be a valid dichotomy.
Development and Early Evaluation of an Inter-professional Post-licensure Education Programme for Extended Practice Roles in Arthritis Care
Authors: Lundon Katie , Shupak Rachel , Schneider Rayfel , Herold McIlroy Jodi
Published: October 2010

Purpose: The Advanced Clinician Practitioner in Arthritis Care (ACPAC) Program was developed to train experienced physical and occupational therapists within extended practice roles with the aim of facilitating optimal, timely, and appropriate delivery of health care to patients with arthritis. This paper presents (1) the development of the ACPAC Program and (2) performance across the programme, as well as early quantitative and qualitative changes in clinical practice roles for the 2006 through 2008 cohorts of ACPAC Program graduates (n=19).

Methods: Measurement of change in skills and knowledge involved standardized baseline and end-of-programme examinations as well as self-evaluation of a number of areas of clinical competence. Practice-focused surveys issued at baseline, mid-programme, and end of programme, as well as at 6 and 12 months after graduation, evaluated the practitioners' integration of advanced knowledge and skills acquired during the ACPAC Program into their extended practice roles.

Results: Participants significantly increased their scores on examinations of clinical knowledge (p<0.001) and skills (p<0.001) from baseline through programme completion. There was an increase in frequency of performance of clinical tasks and assumption of responsibilities related to their extended practice roles from the beginning to the end of the programme. The five areas that changed in relation to these new roles were increased clinical responsibilities, efficiencies in practice settings, roles as educational leaders and mentors in the field of arthritis care, inter-professional collaboration, and improved access to care for patients with arthritis, particularly in remote areas.

Conclusion: Graduates of the ACPAC Program have demonstrated knowledge and skills for practising in extended roles that enhance the available human health resource pool for patients with arthritis.
Clinical Impact and Evidence Base for Physiotherapy in Treating Childhood Chronic Pain
Authors: Ayling Campos Anne , Amaria Khush , Campbell Fiona , McGrath Patricia A.
Published: October 2010

Purpose: As part of the special series on pain, our objectives are to describe the key features of chronic pain in children, present the rationale for interdisciplinary treatment, report a case study based on our biopsychosocial approach, and highlight the integral role of physiotherapy in reducing children's pain and improving function. We also evaluate the evidence base supporting physiotherapy for treating chronic neuropathic pain in children.

Summary of Key Points: Chronic pain affects many children and adolescents. Certain challenging pain conditions begin primarily during adolescence and disproportionately affect girls and women. Children with these conditions require an interdisciplinary treatment programme that includes physiotherapy as well as medication and/or psychological intervention. Converging lines of evidence from cohort follow-up studies, retrospective chart reviews, and one randomized controlled trial support the effectiveness of physiotherapy within an interdisciplinary programme for treating children with chronic pain.

Conclusions: Evidence-based practice dictates that health care providers adopt clear guidelines for determining when treatments are effective and for identifying children for whom such treatments are most effective. Thus, additional well-designed trials are required to better identify the specific physiotherapy modalities that are most important in improving children's pain and function.
Examination of Methods to Estimate Crash Counts by Collision Type
Authors: Geedipally Srinivas Reddy , Patil Sunil , Lord Dominique
Published: October 2010

Multinomial logit (MNL) models have been applied extensively in transportation engineering, marketing, and recreational demand modeling. Thus far, this type of model has not been used to estimate the proportion of crashes by collision type. This study investigated the applicability of MNL models to predict the proportion of crashes by collision type and to estimate crash counts by collision type. MNL models were compared with two other methods described in recent publications to estimate crash counts by collision type: (a) fixed proportions of crash counts for all collision types and (b) collision type models. This study employed data collected between 2002 and 2006 on crashes that occurred on rural, two-lane, undivided highway segments in Minnesota. The study results showed that the MNL model could be used to predict the proportion of crashes by collision type, at least for the data set used. Furthermore, the method based on the MNL model was found useful to estimate crash counts by collision type, and it performed better than the method based on the use of fixed proportions. The use of collision type models, however, was still found to be the best way to estimate crash counts by specific collision type. In cases where collision type models are affected by the small sample size and a low sample-mean problem, the method based on the MNL model is recommended.