bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atrazine and Alachlor Transport in Claypan Soils as Influenced by Differential Antecedent Soil Water Content
Authors: Kazemi H. V. , Anderson S. H. , Goyne K. W. , Gantzer C. J. 
Published: June 2008

AbstractIncreased attention to ground water contamination has encouraged an interest in mechanisms of solute transport through soils. Few studies have investigated the effect of the initial soil water content on the transport and degradation of herbicides for claypan soils. We investigated the effect of claypan soils at initial field capacity vs. permanent wilting level on atrazine and alachlor transport. The soil studied was Mexico silt loam (fine, smectitic, mesic Aeric Vertic Epiaqualf) with a subsoil clay content, primarily montmorillonite, of >40%. Strontium bromide, atrazine, and alachlor were applied to plots; half were at field capacity (Wet treatment), and half were near the permanent wilting point (Dry treatment). Soil cores were removed at selected depths and times, and cores were analyzed for bromide and herbicide concentrations. Bromide, atrazine, and alachlor were detected at the 0.90‐m depth in dry plots within 15 d after experiment initiation. Bromide was detected 0.15 m deeper (P< 0.05) in the Dry compared with the Wet treatment at 1, 7, and 60 d after application and >0.30 m deeper (P< 0.01) in the Dry treatment at 15 and 30 d after application; similar treatment results were found for atrazine and alachlor, although on fewer dates with significant differences. The mobility order of the applied chemicals was bromide > atrazine > alachlor. The atrazine apparent half‐life was significantly longer in the Dry plots compared with the Wet plots. The retardation factor determined from the relative velocity of each herbicide to that of bromide was higher for alachlor than for atrazine. This study identifies the impact that shrinkage cracks have for different moisture conditions on preferential transport of herbicides in claypan soils.
Risks of pollution in water resources: PFC in the Möhne reservoir – what about public opinion?
Authors: Klein Peter 
Published: June 2008

Sewage sludge polluted with high concentrations of PFC (perfluorated organic compounds) was spread as fertiliser on a cornfield in Brilon, Germany. During rainfall PFC are flushed out of the soil and flow into the Möhne and Ruhr River, where drinking water is extracted. PFC in elevated concentrations has been detected in the drinking water in this area. PFCs, used as industrial coating materials, are found ubiquitously, and in high concentrations are believed to be carcinogenic. The drinking-water problem has been mitigated by decontamination of the primary polluted field, a systematic and specific reservoir operation, and more extensive purification of drinking water.
In this region persons predominantly concerned are the population being supplied with drinking-water and some parts of the tourism industry in the Möhne reservoir area.
People in this area ask for a drinking water that is free from dangerous trace elements and residues of pharmaceuticals. Water management actors are called upon to realise consumers' wishes, to implement what is economically and technically possible and to show consumers the possibilities and the limits of drinking-water supply.
PUBLIC ACCEPTANCE OF SEWER FAILURES AND REHABILITATION WORKS: A CASE-STUDY FROM FRANCE AND PORTUGAL1
Authors: Barbier R. , Sousa D. , Montginoul M. 
Published: June 2008

European cities face problems of sewerage and storm water systems wearing out, due to a combination of ageing infrastructure and increased urbanization. Its rehabilitation urges. This paper deals with disturbances on individuals' quality of life due to failures or rehabilitation works. It presents the results of a case-study which comprehends two target-areas: Nantes metropolis in France, and two municipalities of Lisbon metropolis in Portugal. On both areas a questionnaire was applied to a sample of target-populations.
This research results indicate that sewer failures and rehabilitation works are events that induce on disturbances especially in what concerns to the areas of housing and nearby surroundings. Nevertheless, being distinct type of situations, disturbances are lived in different ways as well as differently tolerated. This study also showed that those critical events may provoke, under certain circumstances, trust erosion of costumers towards sewerage utility. The last section aims at providing guidelines that could help local operators to set up a “consumer policy” especially in what concerns to sewer failures and rehabilitation works.
Microleakage of All-ceramic Crowns Using Self-etching Resin Luting Agents
Authors: Trajtenberg C. P. , Caram S. J. , Kiat-amnuay S. 
Published: June 2008

Clinical Relevance
Among the self-adhesive resin cements, Panavia F 2.0 demonstrated less microleakage than RelyX Unicem or Multilink, whether or not a die spacer technique was used.
Depth of Cure of Dental Resin Composites: ISO 4049 Depth and Microhardness of Types of Materials and Shades
Authors: Moore B. K. , Platt J. A. , Borges G. , Chu T-M. G. , Katsilieri I. 
Published: June 2008

Clinical Relevance
Achieving a high degree of cure throughout a 2 mm thickness of light-activated resin composite did not occur for many types and shades of resin composite. Clinicians should check the depth of cure by using the scraping method.
Effect of Prior Acid Etching on Bonding Durability of Single-Step Adhesives
Authors: Watanabe T. , Tsubota K. , Takamizawa T. , Kurokawa H. , Rikuta A. , Ando S. , Miyazaki M. 
Published: June 2008

Clinical Relevance
The ability of acid etching to increase enamel bond strengths varies among single-step self-etch adhesive systems.
Effect of Restorative Technique and Thermal/Mechanical Treatment on Marginal Adaptation and Compressive Strength of Esthetic Restorations
Authors: Paula A. B. , Duque C. , Correr-Sobrinho L. , Puppin-Rontani R. M. 
Published: June 2008

Clinical Relevance
This study demonstrated that esthetic restorations prepared with indirect or direct techniques had similar compressive strengths and marginal adaptation. Marginal deterioration over time was observed for both types of restorations; however, there was an increase in the prevalence of catastrophic fractures among direct restorations.
Reversal of Compromised Bonding in Bleached Enamel Using Antioxidant Gel
Authors: Kaya A. D. , Türkün M. , Arici M. 
Published: June 2008

Clinical Relevance
Dental bond strength is significantly reduced when bonding is performed immediately after bleaching treatments. It has also been reported that the application of an antioxidant after bleaching treatment improves the adhesive bond strength of oxidized enamel tissue. The application of an antioxidant in gel form by the patient makes the application process easier and shortens time spent in the clinic.
Clinical Evaluation of an All-in-one Adhesive in Non-Carious Cervical Lesions with Different Degrees of Dentin Sclerosis
Authors: Ritter A. V. , Heymann H. O. , Swift E. J. , Sturdevant J. R. , Wilder A. D. 
Published: June 2008

Clinical Relevance
Lower scores for marginal discoloration and adaptation were noted when an all-in-one self-etching adhesive was applied to non-carious cervical lesions and compared to a three-step total-etch adhesive.
Comparison of Traditional and Low Sensitivity Whiteners
Authors: Browning W. D. , Chan D. C. , Myers M. L. , Brackett W. W. , Brackett M. G. , Pashley D. H. 
Published: June 2008

Clinical RelevanceThe results of this double-blind, placebo-controlled clinical trial have direct relevance to clinical practice and provide evidence that the addition of low levels of potassium nitrate and/or potassium nitrate and fluoride significantly reduce postoperative sensitivity relative to products that do not contain either agent.
Recent glacier variations at the Aconcagua basin, central Chilean Andes
Authors: Bown Francisca , Rivera Andrés , Acuña César 
Published: June 2008

AbstractThe majority of glaciers in central Chile have receded in recent decades, from >50m to only a few meters per year, mainly in response to an increase in the 0˚C isotherm altitude. The Aconcagua river basin (33˚ S) is one of the major glaciated basins in central Chile, with 121 km2 of ice in 2003. An earlier inventory using 1955 aerial photographs yielded a total surface area of 151 km2, implying a reduction in glacier area of 20% (0.63km2 a–1) over the 48 years. Photographic stereo models, high-resolution satellite images (Landsat, ASTER) and SRTM data have been used to delineate glacier basins. A focus on Glaciar Juncal Norte, one of the largest glaciers in the basin, allows a more detailed analysis of changes. The glacier has exhibited a smaller reduction (14%) between 1955 and 2006, and the resulting elevation changes over this smaller period are not significant. The above reduction rates are lower than in other glaciers of central Chile and Argentina. This trend emphasizes water runoff availability in a river where most of the water in the dry summers is generated by glaciers and snowpack, and where most of the superficial water rights are already allocated. Ongoing hydrological research including modelling of future water runoff will improve our understanding.
A change in seasonality in Greenland during a Dansgaard–Oeschger warming
Authors: Thomas Elizabeth R. , Mulvaney Robert , Wolff Eric W. 
Published: June 2008

AbstractA new sub-seasonal chemical record is presented from the North Greenland Icecore Project (NorthGRIP) ice core during the onset of one of the longest and strongest interstadials of the last glacial period, Dansgaard–Oeschger event 8 (approximately 38 000 years ago). This is the first time that a record of such resolution has been achieved over several metres of deep glacial ice and provides a unique opportunity for using additional parameters to carry out accurate dating using annual-layer counting. The very high-resolution chemical data were used to assess the phasing of various ions and determine changes in the seasonal strength of chemical deposition and the shape of the seasonal cycle. The study shows that a change in seasonality accompanied the dramatic warming transition from stadial to interstadial conditions in Greenland.
Climate sensitivity and mass-balance evolution of Gran Campo Nevado ice cap, southwest Patagonia
Authors: Möller Marco , Schneider Christoph 
Published: June 2008

AbstractA degree-day model extended for surface mass-balance calculations has been applied to derive the sensitivity of Gran Campo Nevado ice cap (GCN), southwest Patagonia, to climate change. Seasonal sensitivity characteristics were computed using automatic weather station data gathered in the period 2000–05. Results indicate pronounced mass-balance sensitivity to temperature during the summer, with monthly values of –0.27±0.01mw.e. K–1. Monthly sensitivity to a 10% precipitation perturbation fluctuates around +0.03mw.e The sensitivity characteristics obtained were used to model the surface mass-balance evolution of GCN during the 20th and 21 st centuries based on monthly means of air temperature and precipitation derived from bias-corrected weather station data and statistically downscaled re-analysis and general climate model data. Surface mass balance shows a persistently negative trend ranging from around +1mw.e. a–1 at the beginning of the 20th century down to almost –1.5mw.e. a–1 during the first years of the 21st century, with only a few positive years occurring occasionally during the second half of the 20th century. The scenario for the end of the 21 st century totals approximately –4.5mw.e. a–1, i.e. an estimated ice volume loss for GCN of 59 km3 during 1900–2099.
Modelling binge–purge oscillations of the Laurentide ice sheet using a plastic ice sheet
Authors: Steen-Larsen H.C. , Dahl-Jensen D. 
Published: June 2008

AbstractA simple combined heat and ice-sheet model has been used to calculate temperatures at the base of the Laurentide ice sheet. We let the ice sheet surge when the basal temperature reaches the pressure-melting temperature. Driving the system with the observed accumulation and temperature records from the GRIP ice core, Greenland, produces surges corresponding to the observed Heinrich events. This suggests that the mechanism of basal sliding, initiated when the basal temperature reaches the melting point, can explain the surges of the Laurentide ice sheet. This study highlights the importance of the surface temperature and accumulation rate as a means of forcing the timing and strength of the Heinrich events, thus implying important ice-sheet climate feedbacks.
The recent evolution of Liligo glacier, Karakoram, Pakistan,and its present quiescent phase
Authors: Belo Marco , Mayer Christoph , Smiraglia Claudio , Tamburini Andrea 
Published: June 2008

AbstractLiligo glacier, in the central eastern Karakoram, Pakistan, is a small, south-to-north-flowing glacier situated in a transverse valley on the left (south) side of Baltoro glacier. New processing of satellite imagery enables a better quantification of terminus oscillations over the past 30 years. From the beginning of the 1970s to the beginning of the 21st century, Liligo glacier advanced about 2 km (60ma–1). The progress was characterized by a significant evolution of terminus morphology, similar to that observed on the same glacier during the advance event near the beginning of the 20th century, and to those of many other Karakoram glaciers. This suggests indications of a surge-type mechanism. Field observations performed in 2004 indicated there was probably no confluence at that time between Liligo and Baltoro glaciers and that a quiescent phase had started in the early years of the 21st century.
Extreme intra-seasonal anomalies in the Amundsen and Bellingshausen sea-ice area, Antarctica, during the austral winter
Authors: de Lima Fabio Ullmann Furtado , de Carvalho Leila M. Véspoli 
Published: June 2008

AbstractWe examine the role of the propagation of atmospheric mid-latitudes wave trains in modulating the Amundsen and Bellingshausen sea-ice area (SIA), Antarctica, on intra-seasonal timescales (20–100 days). Spectral analysis of passive microwave estimates of SIA in the Amundsen and Bellingshausen Seas for 1979–2004 shows significant peaks on intra-seasonal timescales. Previous studies have suggested that variations in SIA are linked to disturbances in atmospheric circulation and sea surface temperature. We show that extreme SIA anomalies on intra-seasonal timescales lag the propagation of subtropical wave trains in the Southern Hemisphere by approximately 10–15 days. The sign of the SIA anomaly depends on the phase of the wave. We present evidence that the number of disturbances that cause extreme anomalies of SIA on intra-seasonal timescales has increased in the last 14 years.
Spatial distribution of debris thickness and melting from remote-sensing and meteorological data, at debris-covered Baltoro glacier, Karakoram, Pakistan
Authors: Mihalcea C. , Mayer C. , Diolaiuti G. , D’Agata C. , Smiraglia C. , Lambrecht A. , Vuillermoz E. , Tartari G. 
Published: June 2008

AbstractA distributed surface energy-balance study was performed to determine sub-debris ablation across a large part of Baltoro glacier, a wide debris-covered glacier in the Karakoram range, Pakistan. The study area is ~124km2. The study aimed primarily at analyzing the influence of debris thickness on the melt distribution. The spatial distribution of the physical and thermal characteristics of the debris was calculated from remote-sensing (ASTER image) and field data. Meteorological data from an automatic weather station at Urdukas (4022ma.s.l.), located adjacent to Baltoro glacier on a lateral moraine, were used to calculate the spatial distribution of energy available for melting during the period 1–15 July 2004. The model performance was evaluated by comparisons with field measurements for the same period. The model is reliable in predicting ablation over wide debris-covered areas. It underestimates melt rates over highly crevassed areas and water ponds with a high variability of the debris thickness distribution in the vicinity, and over areas with very low debris thickness (<0.03 m). We also examined the spatial distribution of the energy-balance components (global radiation and surface temperature) over the study area. The results allow us to quantify, for the study period, a meltwater production of 0.058 km3.
Arctic sea-ice variability revisited
Authors: Stroeve Julienne , Frei Allan , McCreight James , Ghatak Debjani 
Published: June 2008

AbstractThis paper explores spatial and temporal relationships between variations in Arctic sea-ice concentration (summer and winter) and near-surface atmospheric temperature and atmospheric pressure using multivariate statistical techniques. Trend, empirical orthogonal function (EOF) and singular value decomposition (SVD) analyses are used to identify spatial patterns associated with covariances and correlations between these fields. Results show that (1) in winter, the Arctic Oscillation still explains most of the variability in sea-ice concentration from 1979 to 2006; and (2) in summer, a decreasing sea-ice trend centered in the Pacific sector of the Arctic basin is clearly correlated to an Arctic-wide air temperature warming trend. These results demonstrate the applicability of multivariate methods, and in particular SVD analysis, which has not been used in earlier studies for assessment of changes in the Arctic sea-ice cover. Results are consistent with the interpretation that a warming signal has now emerged from the noise in the Arctic sea-ice record during summer. Our analysis indicates that such a signal may also be forthcoming during winter.
Sediment–moss interactions on a temperate glacier: Falljökull, Iceland
Authors: Porter P.R. , Evans A.J. , Hodson A.J. , Lowe A.T. , Crabtree M.D. 
Published: June 2008

AbstractWe present the results of preliminary investigations of globular moss growth on the surface of Falljökull, a temperate outlet glacier of the Vatnajökull ice cap, southern Iceland. Supraglacial debris has provided a basis for moss colonization, and several large (>500m2) patches of moss growth (Racomitrium spp.) are observed on the surface of the glacier. Each area of moss-colonized supraglacial debris shows a downslope increase in sphericity and moss cushion size and a decrease in percentage surface coverage of moss-colonized and bare clasts. It is suggested that moss growth on supraglacial debris allows preferential downslope movement of clasts through an associated increase in both overall mass and sphericity. Thermal insulation by moss cushions protects the underlying ice surface from melt, and the resulting ice pedestals assist in downslope sliding and toppling of moss cushions. The morphology and life cycle of supraglacial globular mosses is therefore not only closely linked to the presence and distribution of supraglacial debris, but also appears to assist in limited down-glacier transport of this debris. This research highlights both the dynamic nature of the interaction of mosses with supraglacial sedimentary systems and the need for a detailed consideration of their role within the wider glacial ecosystem.
Comparison of sea-ice extent and ice-edge location estimates from passive microwave and enhanced-resolution scatterometer data
Authors: Meier Walter N. , Stroeve Julienne 
Published: June 2008

AbstractPassive microwave sea-ice concentration fields provide some of the longest-running and most consistent records of changes in sea ice. Scatterometry-based sea-ice fields are more recently developed data products, but now they provide a record of ice conditions spanning several years. Resolution enhancement techniques applied to scatterometer fields provide much higher effective resolutions (~10 km) than are available from standard scatterometer and passive microwave fields (25–50 km). Here we examine ice-extent fields from both sources and find that there is general agreement between scatterometer data and passive microwave fields, though scatterometer estimates yield substantially lower ice extents during winter. Comparisons with ice-edge locations estimated from AVHRR imagery indicate that enhanced scatterometer data can sometimes provide an improved edge location, but there is substantial variation in the results, depending on the local conditions. A blended product, using both scatterometer and passive microwave data, could yield improved results.
Assessment of techniques for analyzing snow crystals in two dimensions
Authors: Bartlett Stuart John , Rüedi Jean-Daniel , Craig Alasdair , Fierz Charles 
Published: June 2008

AbstractThree-dimensional (3-D) snow analysis techniques provide comprehensive and accurate snow microstructure data. Nevertheless, there remains a requirement for less elaborate methods for snow characterization, as numerical snow models such as SNOWPACK are presently based on two-dimensional (2-D) grain analysis. We present a detailed assessment of various methods and shape descriptors used for snow characterization from digitized images. Dendricity, the ratio of the square of grain perimeter to its area, allows distinction between new and old snow while sphericity distinguishes between faceted and rounded grains. The concept of sphericity is based on curvature, yet another powerful shape descriptor. However, curvatures obtained from images of disaggregated snow grains depend on both resolution and methods chosen. We compared the standard parabola method with a cubic smoothing spline approach for curvature measurement. Applying both methods to parametrically generated shapes, descriptor values were compared with their analytical counterparts. The spline method was found to be able to measure a wider range of curvatures accurately, but both methods suffered from a filtering effect. Although some descriptor errors were as high as 50%, a method for effectively outlining snow grains was found. As well as assessing the classification potential of 2-D analysis on full samples, new descriptors were also investigated.
A bonding process between grains in mechanically disaggregated snow
Authors: Adams Edward E. , Jepsen Steven M. , Close Bryan 
Published: June 2008

AbstractCollections of disaggregated snow particles were examined in a temperature-controlled microscope stage. In addition to necks that appeared to sinter in a manner congruent with the two-particle model, there also appeared unanticipated dendritic growth, which developed on some grains and grew into the pore space. These branches developed preferentially only on part of, and in different directions on, individual grains. Some of these grew enough to join with adjacent grains that were in close proximity but not initially in contact, while the surface of the adjacent grains did not show measurable growth or loss. Growth orientation is hypothesized to be due to crystal habit dependence on temperature. Columnar growth was observed at –5˚C and plate-like at –15˚C. The random growth orientation is in contrast to observed source and sink development aligned with a temperature gradient imposed using a gradient stage. In this case, a source-to-sink directionality across the pore was apparent in which faceted crystals grew at the expense of neighboring source grains. The process of mechanically disaggregating snow produces numerous broken shards and sharp-edged fracture surfaces. We hypothesize that it is the sublimation of these high-surface-energy regions that provides the excess vapor to facilitate the diffusion-limited dendritic growth observed in this ‘equitemperature’, mechanically processed snow.