bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studying Organic Matter Molecular Assemblage within a Whole Organic Soil by Nuclear Magnetic Resonance
Authors: Lattao Charisma , Birdwell Justin , Wang Jim J. , Cook Robert L. 
Published: June 2008

AbstractThis work shows the applicability of two‐dimensional (2D) 1H‐13C heteronuclear correlation (HETCOR) nuclear magnetic resonance (NMR) spectroscopy to the characterization of whole soils. A combination of different mixing times and cross polarization (CP) methods, namely Lee‐Goldberg (LG)‐CP and Ramp‐CP are shown to afford, for the first time, intra‐ and inter‐ molecular connectivities, allowing for molecular assemblage information to be obtained on a whole soil Our results show that, for the brackish marsh histosol under study, two isolated domains could be detected. The first domain consists of O‐alkyl and aromatic moieties (lignocellulose material), while the second domain is comprised of alkyl type moieties (cuticular material). The role of these domains is discussed in terms of hydrophobic organic compound sorption within soil organic matter (SOM), including the possible effects of wetting and drying cycles.
Reclamation of Acid Sulfate Soils Using Lime‐Stabilized Biosolids
Authors: Orndorff Zenah W. , Daniels W. Lee , Fanning Delvin S. 
Published: June 2008

AbstractExcavation of sulfidic materials during construction has resulted in acid rock drainage (ARD) problems throughout Virginia. The most extensive documented uncontrolled disturbance at a single location is Stafford Regional Airport (SRAP) in Stafford, Virginia. Beginning in 1998, over 150 ha of sulfidic Coastal Plain sediments were disturbed, including steeply sloping cut surfaces and spoils placed into fills. Acid sulfate soils developed, and ARD generated on‐site degraded metal and concrete structures and heavily damaged water quality with effects noted over 1 km downstream. The site was not recognized as sulfidic until 2001 when surface soil sampling revealed pH values ranging from 1.9 to 5.3 and peroxide potential acidity (PPA) values ranging from 1 to 42 Mg CaCO3per 1000 Mg material. In February 2002 a water quality program was established in and around the site to monitor baseline pH, EC, NO3–N, NH4–N, PO4–P, Fe, Al, Mn, and SO4–S, and initial pH values as low as 2.9 were noted in on‐site receiving streams. In the spring and fall of 2002, the site was treated with variable rates of lime‐stabilized biosolids, straw‐mulch, and acid‐ and salt‐tolerant legumes and grasses. By October 2002, the site was fully revegetated (≥90% living cover) with the exception of a few highly acidic outcrops and seepage areas. Surface soil sampling in 2003, 2004, and 2006 revealed pH values typically > 6.0. Water quality responded quickly to treatment, although short‐term NH4+release occurred. Despite heavy loadings, no significant surface water P losses were observed.
Indicators of Carbon Storage in U.S. Ecosystems: Baseline for Terrestrial Carbon Accounting
Authors: Negra Christine , Sweedo Caroline Cremer , Cavender‐Bares Kent , O'Malley Robin 
Published: June 2008

AbstractPolicymakers, program managers, and landowners need information about net terrestrial carbon sequestration in forests, croplands, grasslands, and shrublands to understand the cumulative effects of carbon trading programs, expanding biofuels production, and changing environmental conditions in addition to agricultural and forestry uses. Objective information systems that establish credible baselines and track changes in carbon storage can provide the accountability needed for carbon trading programs to achieve durable carbon sequestration and for biofuels initiatives to reduce net greenhouse gas emissions. A multi‐sector stakeholder design process was used to produce a new indicator for the 2008State of the Nation's Ecosystemsreport that presents metrics of carbon storage for major ecosystem types, specifically change in the amount of carbon gained or lost over time and the amount of carbon stored per unit area (carbon density). These metrics have been developed for national scale use, but are suitable for adaptation to multiple scales such as individual farm and forest parcels, carbon offset markets and integrated national and international assessments. To acquire the data necessary for a complete understanding of how much, and where, carbon is gained or lost by U.S. ecosystems, expansion and integration of monitoring programs will be required.
Testing DAYCENT Model Simulations of Corn Yields and Nitrous Oxide Emissions in Irrigated Tillage Systems in Colorado
Authors: Del Grosso S. J. , Halvorson A. D. , Parton W. J. 
Published: June 2008

AbstractAgricultural soils are responsible for the majority of nitrous oxide (N2O) emissions in the USA. Irrigated cropping, particularly in the western USA, is an important source of N2O emissions. However, the impacts of tillage intensity and N fertilizer amount and type have not been extensively studied for irrigated systems. The DAYCENT biogeochemical model was tested using N2O, crop yield, soil N and C, and other data collected from irrigated cropping systems in northeastern Colorado during 2002 to 2006. DAYCENT uses daily weather, soil texture, and land management information to simulate C and N fluxes between the atmosphere, soil, and vegetation. The model properly represented the impacts of tillage intensity and N fertilizer amount on crop yields, soil organic C (SOC), and soil water content. DAYCENT N2O emissions matched the measured data in that simulated emissions increased as N fertilization rates increased and emissions from no‐till (NT) tended to be lower on average than conventional‐till (CT). However, the model overestimated N2O emissions. Lowering the amount of N2O emitted per unit of N nitrified from 2 to 1% helped improve model fit but the treatments receiving no N fertilizer were still overestimated by more than a factor of 2. Both the model and measurements showed that soil NO3− levels increase with N fertilizer addition and with tillage intensity, but DAYCENT underestimated NO3− levels, particularly for the treatments receiving no N fertilizer. We suggest that DAYCENT could be improved by reducing the background nitrification rate and by accounting for the impact of changes in microbial community structure on denitrification rates.
Temporal Variation and Persistence of Bacteria in Streams
Authors: Koirala Shesh R. , Gentry Randall W. , Perfect Edmund , Schwartz John S. , Sayler Gary S. 
Published: June 2008

AbstractBetter understanding of bacterial fate and transport in watersheds is necessary for improved regulatory management of impaired streams. Novel statistical time series analyses of coliform data can be a useful tool for evaluating the dynamics of temporal variation and persistence of bacteria within a watershed. For this study, daily total coliform data for the Little River in East Tennessee from 1 Oct. 2000 to 31 Dec. 2005 were evaluated using novel time series techniques. The objective of this study was to analyze the total coliform concentration data to: (i) evaluate the temporal variation of the total coliform, and (ii) determine whether the total coliform concentration data demonstrated any long‐term or short‐term persistence. For robust analysis and comparison, both time domain and frequency domain approaches were used for the analysis. In the time domain, an autoregressive moving average approach was used; whereas in the frequency domain, spectral analysis was applied. As expected, the analyses showed that total coliform concentrations were higher in summer months and lower in winter months. However, the more interesting results showed that the total coliform concentration exhibited short‐term as well as long‐term persistence ranging from about 4 wk to approximately 1 yr, respectively. Comparison of the total coliform data to hydrologic data indicated both runoff and baseflow are responsible for the persistence.
Research Priorities for Coordinating Management of Food Safety and Water Quality
Authors: Crohn David M. , Bianchi Mary L. 
Published: June 2008

AbstractEfforts to exclude disease organisms from farms growing irrigated lettuce and leafy vegetables on California's central coast are conflicting with traditionally accepted strategies to protect surface water quality. To begin resolving this dilemma, over 100 officials, researchers, and industry representatives gathered in April 2007 to set research priorities that could lead to effective co‐management of both food safety and water quality. Following the meeting, research priorities were refined and ordered by way of a Delphi process completed by 35 meeting participants. Although water quality and food safety experts conceptualized the issues differently, there were no deep disagreements with respect to research needs. Top priority was given to investigating the fate of pathogens potentially present on farms. Intermediate priorities included characterizing the influence of specific farm management practices on food safety and improving our understanding of vector processes. A scientific subdiscipline focusing on competing risks is needed to characterize and resolve conflicts between human and environmental health.
The Prediction Error of Bornhuetter/Ferguson
Authors: Mack Thomas 
Published: June 2008

Together with the Chain Ladder (CL) method, the Bornhuetter/Ferguson (BF) method is one of the most popular claims reserving methods. Whereas a formula for the prediction error of the CL method has been published already in 1993, there is still nothing equivalent available for the BF method. On the basis of the BF reserve formula, this paper develops a stochastic model for the BF method. From this model, a formula for the prediction error of the BF reserve estimate is derived.Moreover, the model gives important advice on how to estimate the parameters for the BF reserve formula. E.g. it turns out that the appropriate BF development pattern is different from the CL pattern. This is a nice add-on as it makes BF to a standalone reserving method which is fully independent from CL. The other parameter required for the BF reserve is the well-known initial estimate for the ultimate claims amount. Here the stochastic model clearly shows what has to be meant with ‘initial’.In order to apply the formula for the prediction error, the actuary must assess his uncertainty about both sets of parameters, about the development pattern and about the initial ultimate claims estimates. But for both, much guidance can be drawn from the estimates itself and from the run-off data given. Finally, a numerical example shows how the resulting prediction error compares to the one of the CL method.
Comparison of Enamel and Dentin Microshear Bond Strengths of a Two-step Self-etching Priming System with Five All-in-One Systems
Authors: Burrow M. F. , Kitasako Y. , Thomas C. D. , Tagami J. 
Published: June 2008

Clinical Relevance
The newest all-in-one adhesives demonstrated bond strengths similar to other currently available enamel/dentin adhesives. Bonding to enamel showed lower bond strengths; however, clinical data are needed to determine the relevance.
Code Single Point Positioning Using Nominal Gnss Constellations (Future Perception)
Authors: Farah A. 
Published: June 2008

Code Single Point Positioning Using Nominal Gnss Constellations (Future Perception)
Global Navigation Satellite Systems (GNSS) have an endless number of applications in industry, science, military, transportation and recreation & sports. Two systems are currently in operation namely GPS (the USA Global Positioning System) and GLONASS (the Russian GLObal NAvigation Satellite System), and a third is planned, the European satellite navigation system GALILEO. The potential performance improvements achievable through combining these systems could be significant and expectations are high. The need is inevitable to explore the future of positioning from different nominal constellations. In this research paper, Bernese 5.0 software could be modified to simulate and process GNSS observations from three different constellations (GPS, Glonass and Galileo) using different combinations. This study presents results of code single point positioning for five stations using the three constellations and different combinations.
Static Network Code Dgps Positioning vs. Carrier Phase Single Baseline Solutions for Short Observation time and Medium-Long Distances
Authors: Bakuła M. 
Published: June 2008

Static Network Code Dgps Positioning vs. Carrier Phase Single Baseline Solutions for Short Observation time and Medium-Long DistancesGPS land surveys are usually based on the results of processing GPS carrier phase data. Code or pseudorange observations due to considerations of accuracy requirements and robustness are preferred in navigation and some GIS applications. Generally, the accuracy of that positioning is in the range of about 1-2 meters or so, on average. But the main problem in code GPS positioning is to know how to estimate the real accuracy of DGPS positions. It is not such an easy process in code positioning when one reference station is used. In most commercial software, there are no values of accuracy but only positions are presented. DGPS positions without estimated errors cannot be used for surveying tasks and for most GIS applications due to the fact that every point has to be have accuracy determined. However, when we used static GPS positioning, it is well known that the accuracy is determined, both during baseline processing and next by the adjustment of a GPS network. These steps of validation with redundancy in classical static phase baseline solutions allow wide use of static or rapid static methods in the main land surveying tasks. Although these control steps are commonly used in many major surveying and engineering tasks, they are not always effective in terms of short-observation-time sessions. This paper presents a new network DGPS approach of positioning with the use of at least three reference stations. The approach concerns also valid accuracy estimation based on variance-covariance (VC) matrix in the least-squares (LS) calculations. The presented network DGPS approach has the ability of reliable accuracy estimation. Finally, network DGPS positioning is compared with static baselines solutions where five-min sessions were taken into consideration for two different rover stations. It was shown that in a short observation time of GPS positioning, code network DGPS results can give even centimetre accuracy and can be more reliable than static relative phase positioning where gross errors often happen.
Monitoring surging glaciers of the Pamirs, central Asia, from space
Authors: Kotlyakov V.M. , Osipova G.B. , Tsvetkov D.G. 
Published: June 2008

AbstractThe evolution of surging glaciers of the Pamirs, central Asia, has been studied using repeat remote-sensing surveys in the Institute of Geography, Russian Academy of Sciences, since the early 1970s. We use images obtained from national Resurs-F satellites (1972–91), as well as Landsat 7 and Terra (1999–2006), to provide a basis for monitoring of surging glaciers, aimed at developing their inventory, studying the causes and mechanisms of surges and examining the timing and extent of glacial catastrophes. The inventory from the early 1990s allows identification of 215 glaciers with a dynamically unstable regime. We discovered 51 surging glaciers. Up until 2006, 10 more surges had occurred. We use stereoscopic deciphering and photogrammetric processing of consecutive satellite images to study the morphology and ice-velocity changes of several compound surging glaciers. We analyze the results of monitoring of Bivachny and Oktyabr’sky glaciers from 1972 to 1991 and Sugran glacier from 1972 to 2006. Two surges of Sugran glacier occurred during this time: an internal surge in 1976–80, and a surge with glacier tongue advance as far as 4.5 km in 2000–05. The role of damming in compound glacier systems is examined. Satellite-based monitoring is now the only method for obtaining initial information about the state and fluctuations of such glaciers.
At what depth is the Eemian layer expected to be found at NEEM?
Authors: Buchardt Susanne L. , Dahl-Jensen Dorthe 
Published: June 2008

AbstractNo continuous record from Greenland of the Eemian interglacial period (130–115 ka BP) currently exists. However, a new ice-core drill site has been suggested at 77.449˚ N, 51.056˚Win north-west Greenland (North Eemian or NEEM). Radio-echo sounding images and flow model investigations indicate that an undisturbed Eemian record may be obtained at NEEM. In this work, a two-dimensional ice flow model with time-dependent accumulation rate and ice thickness is used to estimate the location of the Eemian layer at the new drill site. The model is used to simulate the ice flow along the ice ridge leading to the drill site. Unknown flow parameters are found through a Monte Carlo analysis of the flow model constrained by observed isochrones in the ice. The results indicate that the Eemian layer is approximately 60m thick and that its base is located approximately 100m above bedrock.
Surface characteristics at Dome A, Antarctica: first measurements and a guide to future ice-coring sites
Authors: Cunde Xiao , Yuansheng Li , Allison Ian , Shugui Hou , Dreyfus Gabrielle , Barnola Jean-Marc , Jiawen Ren , Lingen Bian , Shenkai Zhang , Kameda Takao 
Published: June 2008

AbstractAn assessment of the glaciological and meteorological characteristics of Dome A, the summit of the East Antarctic ice sheet, is made based on field investigations during the austral summer of 2004/05. Knowledge of these characteristics is critical for future international studies such as deep ice-core drilling. The assessment shows that: (1) Dome A is characterized by a very low 10m depth firn temperature, –58.3˚C (nearly 3˚C lower than at EPICA Dome C and 1˚C lower than at Vostok). (2) Automatic weather station (AWS) measurements of snow surface height and reference layers in a snow pit indicate the present-day snow accumulation rate at Dome A is within the range 1–3cmw.e. a–1. Densification models suggest a range of 1–2cmw.e. a–1. This is lower than at other sites along the ice divide of East Antarctica (IDEA). Annual layers at Dome A are thus potentially thinner than at other sites, so that a longer record is preserved in a given ice thickness. (3) The average wind speed observed at Dome A (<4ms–1) is lower than at other sites along IDEA. Together, these parameters, combined with radio-echo sounding data and information on the subglacial drainage distribution beneath Dome A, suggest Dome A as a candidate site for obtaining the oldest ice core.
Spatial and temporal variability in the snowpack of a High Arctic ice cap: implications for mass-change measurements
Authors: Bell Christina , Mair Douglas , Burgess David , Sharp Martin , Demuth Michael , Cawkwell Fiona , Bingham Robert , Wadham Jemma 
Published: June 2008

AbstractInterpretation of ice mass elevation changes observed by satellite altimetry demands quantification of the proportion of elevation change which is attributable to variations in firn densification. Detailed stratigraphic logging of snowpack structure and density was carried out at ~1km intervals along a 47 km transect on Devon Ice Cap, Canada, in spring (pre-melt) and autumn (during/ after melt) 2004 and 2006 to characterize seasonal snowpack variability across the full range of snow facies. Simultaneous meteorological measurements were gathered. Spring (pre-melt) snowpacks show low variability over large spatial scales, with low-magnitude changes in density. The end-of-summer/ autumn density profiles show high variability in both 2004 and 2006, with vastly different melt regimes generating dissimilar patterns of ice-layer formation over the two melt seasons. Dye-tracing experiments from spring to autumn 2006 reveal that vertical and horizontal distribution of meltwater flow within and below the annual snowpack is strongly affected by the pre-existing, often subtle stratigraphic interfaces in the snowpack, rather than its bulk properties. Strong interannual variability suggests that using a simple relationship between air temperature, elevation and snowpack densification to derive mass change from measurements of elevation change across High Arctic ice caps may be misguided. Melt timing and duration are important extrinsic factors governing snowpack densification and ice-layer formation in summer, rather than averaged air temperatures.
Snow depth in eastern Europe in relation to circulation patterns
Authors: Bednorz Ewa , Wibig Joanna 
Published: June 2008

AbstractRotated principal components of the 500 hPa geopotential heights in the Euro-Atlantic sector are used as indicators of circulation pattern intensity. Daily snow-cover depth data for the years 1951–95 from 71 eastern European stations are examined. Maps of linear correlation coefficient between monthly change in snow depth and rotated principal components are presented. The positive and negative extremes of each circulation pattern are analyzed, and positive and negative snow-depth signals indicated. A daily analysis of relationships between snow depth and circulation pattern is performed for three locations. The strongest impact of the atmospheric circulation on changes in snow depth is observed in the south and west of the study area, where the eastern European (EE) and central European circulation patterns are found to have the greatest impact. The North Atlantic Oscillation (NAO) impact on the snow depth in eastern Europe is limited to the beginning and the end of winter. Snow cover has low variability in northeastern Europe (where the Scandinavian (SC) pattern is of greatest importance) and low sensitivity to change in the atmospheric circulation. The decrease in snow-cover depth observed in spring is related to the NAO, SC and EE patterns, the latter being important for snow-cover depth fluctuations over northeastern Europe in April.
Self‐Sterilized EVOH‐TiO2 Nanocomposites: Interface Effects on Biocidal Properties
Authors: Cerrada Maria L. , Serrano Cristina , Sánchez‐Chaves Manuel , Fernández‐García Marta , Fernández‐Martín Fernando , de Andrés Alicia , Riobóo Rafael J. Jiménez , Kubacka Anna , Ferrer Manuel , Fernández‐García Marcos 
Published: June 2008

AbstractNanocomposite materials obtained by TiO2 incorporation into ethylene–vinyl alcohol copolymers, extensively used in food packaging, are prepared via a straightforward melting process. The structural characteristics of the nanocomposites are examined using wide and small angle X‐ray scattering (WAXS/SAXS), and vibrational infrared and Raman spectroscopies. A microscopy (SEM/TEM) study shows that the materials obtained are highly homogeneous at the nanometric scale, exhibiting an intimate contact between both the organic and inorganic components. TiO2 incorporation into this polymer matrix renders self‐sterilized nanocomposite materials upon light excitation, which are tested against nine micro‐organisms (gram‐positive and gram‐negative bacteria, cocci, and yeasts) typically involved in food contamination and/or degradation. Overall, the nanocomposites display an impressive performance in the killing of all micro‐organisms with a maximum for an oxide content between 2–5 wt %. The measurement of the physico‐chemical properties together with the structural characterization of the materials provide conclusive evidence that the nanocomposites biocidal capability born of the nanometric organo‐inorganic interface and rationalize the existence of a maximum as a function of the TiO2 content.