bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimating Niche Width Using Stable Isotopes in the Face of Habitat Variability: A Modelling Case Study in the Marine Environment
Authors: Cummings David O. , Buhl Camille , Lee Raymond W. , Simpson Stephen J. , Holmes Sebastian P.
Published: August 2012

Distributions of stable isotopes have been used to infer an organism's trophic niche width, the ‘isotopic niche’, and examine resource partitioning. Spatial variation in the isotopic composition of prey may however confound the interpretation of isotopic signatures especially when foragers exploit resources across numerous locations. In this study the isotopic compositions from marine assemblages are modelled to determine the role of variation in the signature of prey items and the effect of dietary breadth and foraging strategies on predator signatures. Outputs from the models reveal that isotopic niche widths can be greater for populations of dietary specialists rather than for generalists, which contravenes what is generally accepted in the literature. When a range of different mixing models are applied to determine if the conversion from δ to p-space can be used to improve model accuracy, predator signature variation is increased rather than model precision. Furthermore the mixing models applied failed to correctly identify dietary specialists and/or to accurately estimate diet contributions that may identify resource partitioning. The results presented illustrate the need to collect sufficiently large sample sizes, in excess of what is collected under most current studies, across the complete distribution of a species and its prey, before attempts to use stable isotopes to make inferences about niche width can be made.
Puzzling gender differently? Acomparative study of newspaper coverage in Austria, Germany and Switzerland
Authors: Kinnebrock Susanne
Published: August 2012

Puzzling gender differently; the title of this article may appear to be ambiguous, since it refers to at least two different factors. The first of these relates to varying gender representations within the German, Austrian and German-speaking Swiss cultures. In particular, the focus
is on the differences in gender portrayals that are the result of different cultural contexts. The second element refers to my attempt to approach gender differences in a way that does not necessarily reproduce the established binary order of male–female. Moreover, I will also present
some methodological reflections on how to work creatively with the category of ‘gender’ in empirical studies and how to puzzle gender differently.
Teenage girls’ views and practices of ‘sexy’ self-portraits in a Taiwanese social networking site
Authors: Wang Yin-Han
Published: August 2012

This article explores girls’ ideas and, for some, ideals about self-presentation on the Internet in relation to femininity. It focuses specifically on the representational style of the sexy – a style easy to observe by the onlookers in girls’ self-portraits posted
online – as an example of the way in which ‘sexy femininity’ is understood and practiced by girls. The findings are based on interviews with 44 Taiwanese girls aged 13–20, and observation of their personal album space on the social networking site Wretch. The article
aims to extend the current discussion about media and girlhood sexuality beyond the ‘gendered moral panic’ by illuminating how girls themselves have myriad ways of understanding sexiness, just as adults do, how appearing sexy online is not without underlying tensions, especially
when taking into account the responses of their audiences, and how negotiating sexiness in self-portraits constitutes opportunities for girls to learn and practice gender performance.
Exploring authority in the film blogosphere: differences between male and female bloggers regarding blog content and structure
Authors: Verboord Marc
Published: August 2012

The impact of the cultural blogosphere has – in contrast to that of the political blogosphere – rarely been studied to date, although the number of cultural blogs is rapidly increasing. This article offered an explorative study of film blogs by analysing structural and content
characteristics of 180 film blogs, which varied in the degree of authority as attributed in the Technorati Index. Special attention was paid to the presence of male and female contributors. The results show that blogs resemble mainstream media more with increasing authority, suggesting institutionalization
processes. At the same time, authority is a fairly instable trait in the blogosphere. Among blog contributors only a quarter is female, implying that the emancipatory power of Web 2.0 may be overestimated.
Decoding media images of political leaders: The perspective of young adults on the relation of gender and power
Authors: Mueller Kathrin Friederike
Published: August 2012

How are media representations of male and female political leaders appropriated by young adults? Do young people negotiate questions of occupational success during media use? The article gives answers to these questions by referring to a qualitative audience study that analyses the
negotiation of femininity and power as well as the (de-)construction of gender. It is based on focus groups with 17-19-year-old male and female students with different educational backgrounds. The findings show that the young adults do not reproduce traditional concepts of femininity: Male
and female political leaders are described as powerful persons. Nevertheless, gender is articulated and therefore reconstructed in appropriation. Not female politicians but managers are seen as examples of reaching leading positions. Altogether, media images of female leaders are decoded as
proof of potential success of women and therefore are meaningful for society.
Gendered scrobbling: Listening behaviour of young adults on Last.fm
Authors: Berkers Pauwke
Published: August 2012

Combining insights from the psychology and sociology of music, this article addresses the extent to which the listening behaviour of young adults differs between men and women with regard to (1) preferred music genres, (2) gender of music acts and (3) omnivorousness. Drawing on innovative
data from the music-based social networking site Last.fm, the analyses show that young females listen more often to 'softer' and more mainstream music genres, to female acts and to a wider range of genres than males. Furthermore, by looking into actual listening behaviour and user-generated
genre classifications - instead of self-reported preferences - this study contributes to research on gender stratification in music taste, showing that within male-dominated genres young women have carved out particular feminized niches, that women's pro-female bias is stronger within male-dominated
music genres and that the gender difference in omnivorousness disappears when we examine only respondents' favourite music genres.
“According to His Own Judgment”: The American Catholic Encounter with Organic Evolution, 1875–1896
Authors: Mislin David
Published: August 2012

Between 1875 and 1896, the response of American Catholic thinkers to theories of organic evolution was characterized by little rancor and discord. Among the small number of clergy and lay intellectuals who addressed the subject, there existed a wide variety of positions on the scientific plausibility of such theories. These prominent Catholics were not deeply wedded to their views, however, and few saw any significant conflict between their religious commitments and biological evolution. This state of affairs stemmed from several elements of Catholic thought, particularly as it existed in the late-nineteenth-century United States: the conviction that church authority could mediate any apparent tension between science and Scripture; the affirmation that theories of organic evolution would not undermine existing theological tenets about the relationship between religion and science, as well as that between First Cause and secondary causes in nature; the belief that Catholic intellectuals since the time of Augustine had endorsed a system of natural development that closely resembled modern conceptions of evolution; and, most important, the insistence that the theory could be reconciled with the resurgent neo-Scholasticism that had come to dominate Catholic thought. Organic evolution proved far less significant in discussions of the relationship between religion and science among American Catholics than it did among Protestants, and it did little to contribute to the split of Catholics into liberal and conservative groups.
The Death of Mormon Separatism in American Universities, 1877–1896
Authors: Simpson Thomas W.
Published: August 2012

The transformation of Mormonism from a small, persecuted sect into an established, global faith has attracted scholarly attention for decades. By all accounts, the late nineteenth and early twentieth centuries were critical for the church's evolution and modernization. The rapidity of the change, however, leaves nagging questions. After years of costly, principled resistance, how could Mormons, with any semblance of dignity and self-respect, suddenly embrace the institutions and values of their tormentors? How did members of the nineteenth century's “most despised large group” become so loyal to the United States in the twentieth?

This essay explores the unique, crucial role that American universities played in fostering Mormon-Gentile reconciliation. Right when the animosities were at fever pitch—in the decades between the death of Brigham Young (1877) and Utah's admission into the Union as the forty-fifth state (1896)—the American university became a liminal, quasi-sacred space where Mormons experienced a radical transformation of consciousness and identity. In the process, they developed an enduring devotion to non-Mormon institutions and deference to non-Mormon expertise. These extra-ecclesial loyalties would dismantle the ideological framework of Mormon separatism and pave the way for Mormons' voluntary reimmersion into the mainstream of American life.
The Quest for Quality: Optimising Platinum Casting for 21st Century Needs
Authors: Frye* Teresa , Fischer-Buehner Joerg
Published: August 2012

There is much interest in developing new casting alloys and techniques for platinum. Despite numerous advances in casting equipment and technology, there are still many areas to improve upon which can reduce production costs and result in a sturdier product. This review examines the casting behaviours of 900 and 950 platinum alloys with additions to increase the hardness. The main aim of this study was to discover the solidification patterns of platinum alloys from molten to the solid state, with characteristics assessed including shrinkage porosity, gas porosity and form filling. In addition, alloy hardness levels and the effects of thermal post-processing of castings were explored.
The Platinum Decathlon – A Tribute to the Foresight of Antoine Baumé
Authors: Barnard Chris , Fones Andrew
Published: August 2012

Ten application areas and ten properties of platinum (or its alloys) are selected here to represent a “platinum decathlon”. Platinum has a unique combination of properties which make it eminently suitable for many applications from jewellery to anticancer drugs, from high-temperature engineering to a range of catalytic applications. The 18th century French chemist Antoine Baumé foresaw the desirability of platinum’s use in industry and its use today in many essential areas bears this out.
Brentuximab Vedotin in Transplant-Naïve Patients with Relapsed or Refractory Hodgkin Lymphoma: Analysis of Two Phase I Studies
Authors: Forero-Torres Andres , Fanale Michelle , Advani Ranjana , Bartlett Nancy L. , Rosenblatt Joseph D. , Kennedy Dana A. , Younes Anas
Published: August 2012

Background.

Brentuximab vedotin is an antibody-drug conjugate designed to selectively deliver monomethyl auristatin E, a microtubule-disrupting agent, to CD30-expressing cells. Brentuximab vedotin induces durable objective responses in patients with relapsed or refractory Hodgkin lymphoma (HL) after autologous stem cell transplantation (ASCT). The objective of this post-hoc analysis was to characterize the safety and efficacy of brentuximab vedotin for patients with relapsed or refractory HL who refused or were ineligible for ASCT.

Methods.

This case series included 20 transplant-naïve patients who were enrolled in two phase I multicenter studies. Patients received brentuximab vedotin intravenously every 3 weeks or every week for 3 out of 4 weeks.

Results.

The majority of patients were transplant-naïve because of chemorefractory disease. Median age was 31.5 years (range, 12–87 years). Treatment-emergent adverse events in >20% of patients were peripheral neuropathy, fatigue, nausea, pyrexia, diarrhea, weight decreased, anemia, back pain, decreased appetite, night sweats, and vomiting; most events were grade 1 or 2. Six patients obtained objective responses: two complete remissions and four partial remissions. Median duration of response was not met; censored durations ranged from >6.8 to >13.8 months. Three of six responders subsequently received ASCT.

Conclusion.

Brentuximab vedotin was associated with manageable adverse events in transplant-naïve patients with relapsed or refractory HL. The objective responses observed demonstrate that antitumor activity is not limited to patients who received brentuximab vedotin after ASCT. The promising activity observed in this population warrants further study.
Development of a novel mortar for use with unfired clay bricks
Authors: Lawrence Mike , Heath Andrew , Walker Pete
Published: August 2012

Interest in traditional unfired clay building materials, including cob, earth brick, and rammed earth, has grown in the UK in recent years. Although the use of vernacular techniques, such as cob and rammed earth, has raised the profile of earthen architecture, a wider impact on modern construction is more likely to come from modern innovations such as unfired extruded clay masonry units and premixed plasters. Traditional unfired clay walls often have basal widths of 300 mm or more, providing an inherent stability and resistance to toppling through self-weight. Masonry units extracted from UK brick production lines before the firing process are typically 100 mm wide, which requires good mortar-brick bond strength to meet structural robustness requirements in a typical 2.4 m high wall. In testing, traditional mortars based on clay, cement or lime, have not provided sufficient strength. This paper examines the bonding of unfired clay units with unconventional mortars based on novel binders. It reports on the development of a mortar which appears to be suitable for a wide range of clay types. This mortar can be readily recycled and has a carbon footprint lower than many alternative binders. Results of long-term bond strengths and the structural performance of masonry walls are given, which demonstrate the suitability of this mortar for use with unfired clay masonry units.
Model tests on geosynthetic-reinforced stone columns: a comparative study
Authors: Ali K. , Shahu J.T. , Sharma K.G.
Published: August 2012

ABSTRACT: The use of stone columns is popular as a ground-reinforcing technique for supporting flexible structures on soft to very soft soils. When a very soft soil improved by stone columns is loaded, the stone columns undergo excessive bulging, because the very low lateral confinement provided by such a soil gives rise to a very low failure stress of the composite ground. The performance of stone columns in such conditions can be improved either by encasing them with geosynthetics or by placing horizontal strips of geosynthetics within the columns at regular intervals. In the present study, model tests have been carried out on short, floating and fully penetrating single columns with and without reinforcement to evaluate the relative improvement in the failure stress of the composite ground due to different types of reinforcement. A comparative evaluation of the column shape on exhumation reveals subtle differences in failure mode due to the different configurations and types of reinforcement. Whereas for the end-bearing stone columns encasement is clearly the best method, for the floating columns there is no significant difference between the performance of the horizontal strip reinforcement and that of the encasement. For end-bearing columns a geogrid is the best type of geosynthetic to use for both types of reinforcement, but for floating columns the best types of geosynthetic are geogrid as the horizontal strip and geotextile as the encasement.
Model tests for anchored geosynthetic slope systems under dry and seepage conditions
Authors: Chen R.-H. , Chi P.-C. , Fon K.-Y.
Published: August 2012

ABSTRACT: The anchored geosynthetic system (AGS), which combines anchors or nails with natural or synthetic geotextiles to form a flexible reinforcing system, can stabilise steep soil slopes. In this study, a series of model tests on steep slopes of sandy soil were performed to investigate the mechanism and failure behaviour of slopes reinforced with two AGS systems. Particle image velocimetry was employed to measure the displacement of sand particles, and to identify the sliding zones. The effects of slope angle (50° and 70°), reinforcement type (wires and nails), anchorage force and seepage condition were investigated. The test results showed that application of a geotextile contributed to effectively retain soil particles, prevent accumulation of water pressure in the slope, and restrain the run-out distance when the slope failed. With regard to the failure mode, dry slopes anchored with stainless wires behaved as a wedge sliding, whereas a circular failure mode was observed in slopes subjected to seepage. On the other hand, the failure of the slope reinforced with nails was similar to a coherent block sliding. Limit equilibrium analysis was also employed to examine the stabilities of slopes, and proved itself a reliable method for such examination.
On measuring the hydraulic transmissivity of the geotextile cover of geosynthetic clay liners
Authors: Abuel-Naga H.M. , Bouazza A. , Lalot E.
Published: August 2012

ABSTRACT: This paper presents a new approach to the utilisation of a flexible-wall permeameter to measure the hydraulic transmissivity of a geotextile. The proposed method is simple, and requires neither additional equipment nor a special test procedure. To highlight the features of the proposed test method, the results of tests conducted on the cover geotextile specimen of a geosynthetic clay liner under different confining pressures are presented and discussed. This study was a part of larger project investigating leakage rates through composite liners comprising a geomembrane containing defects overlying a geosynthetic clay liner.
Landscape‐scale patterns in tree occupancy and abundance in subarctic Alaska
Authors: Roland Carl A. , Schmidt Joshua H. , Nicklen E. Fleur
Published: August 2012

Recent studies suggest that climate warming in interior Alaska may result in major shifts from spruce‐dominated forests to broadleaf‐dominated forests or even grasslands. To quantify patterns in tree distribution and abundance and to investigate the potential for changes in forest dynamics through time, we initiated a spatially extensive vegetation monitoring program covering 1.28 million ha in Denali National Park and Preserve (DNPP). Using a probabilistic sampling design, we collected field measurements throughout the study area to develop spatially explicit Bayesian hierarchical models of tree occupancy and abundance. These models demonstrated a strong partitioning of the landscape among the six tree species in DNPP, and allowed us to account for and examine residual spatial autocorrelation in our data. Tree distributions were governed by two primary ecological gradients: (1) the gradient from low elevation, poorly drained, permafrost‐influenced sites with shallow active layers and low soil pH (dominated by Picea mariana) to deeply thawed and more productive sites at mid‐elevation with higher soil pH on mineral substrate (dominated by Picea glauca); and (2) the gradient from older, less recently disturbed sites dominated by conifers to those recently affected by disturbance in the form of fire and flooding with increased occupancy and abundance of broadleaf species. We found that the establishment of broadleaf species was largely dependent on disturbance, and mixed forests and pure stands of broadleaf trees were relatively rare and occurred in localized areas. Contrary to recent work in nearby areas of interior Alaska, our results suggest that P. glauca distribution may actually increase in DNPP under warming conditions rather than decline as previously predicted, as P. glauca expands into areas formerly underlain by permafrost. We found no evidence of a shift to broadleaf forests in DNPP, particularly in the poorly drained basin landscape positions that may be resistant to such changes. Overall, our results indicate that probabilistic sampling conducted at a landscape scale can improve inference relative to the habitat associations driving the distribution and abundance of trees in the boreal forest and the potential effects of climate change on them.
Effect of Biosolids Processing on Lead Bioavailability in an Urban Soil
Authors: Brown Sally , Chaney Rufus L. , Hallfrisch Judith G. , Xue Qi
Published: August 2012

The potential for biosolids products to reduce Pb availability in soil was tested on a high Pb urban soil with biosolids from a treatment plant that used different processing technologies. High Fe biosolids compost and high Fe + lime biosolids compost from other treatment plants were also tested. Amendments were added to a Pb‐contaminated soil (2000 mg kg−1 Pb) at 100 g kg−1 soil and incubated for 30 d. Reductions in Pb bioavailability were evaluated with both in vivo and in vitro procedures. The in vivo study entailed feeding a mixture of the Pb‐contaminated soil and AIN93G Basal Mix to weanling rats. Three variations of an in vitro procedure were performed as well as conventional soil extracts [diethylenetriaminepentaacetic acid (DTPA) and Ca(NO3)2] and sequential extraction. Addition of the high Fe compost reduced the bioavailability of soil Pb (in both in vivo and in vitro studies) by 37 and 43%, respectively. Three of the four compost materials tested reduced Pb bioavailability more than 20%. The rapid in vitro (pH 2.3) data had the best correlation with the in vivo bone results (R = 0.9). In the sequential extract, changes in partitioning of Pb to Fe and Mn oxide fractions appeared to reflect the changes in in vivo Pb bioavailability. Conventional extracts showed no changes in metal availability. These results indicate that addition of 100 g kg−1 of high Fe and Mn biosolids composts effectively reduced Pb availability in a high Pb urban soil.
Arsenic Distribution in Florida Urban Soils
Authors: Chirenje T. , Ma L. Q. , Szulczewski M. , Littell R. , Portier K. M. , Zillioux E.
Published: August 2012

Arsenic contamination is of concern due to its effect as a carcinogen. Understanding the distribution of arsenic in urban soils is important for establishing baseline concentrations from which anthropogenic effects can be measured. The soil cleanup target level (SCTL) for arsenic in Florida (0.8 and 3.7 mg kg−1 in residential and commercial areas, respectively) is lower than in most states and is near the arsenic background concentrations in Florida soils. The objective of this study was to characterize the distribution of arsenic in the soils of two Florida cities, Gainesville and Miami. More than 200 soil samples were collected from three land‐use classes in each city (residential, commercial, and public land), digested with USEPA Method 3051a, and analyzed with graphite furnace atomic absorption spectrophotometry. Arsenic concentrations varied greatly in Gainesville, ranging from 0.21 to approximately 660 mg kg−1 with a geometric mean (GM) of 0.40 mg kg−1 (after discarding outliers), which was significantly lower than the GM of 2.81 mg kg−1 in Miami, although Miami samples ranged only from 0.32 to approximately 110 mg kg−1 Arsenic concentrations in 29 and 4% of the Gainesville soil samples and 95 and 33% of the Miami samples exceeded the Florida residential and commercial SCTL, respectively. This study is the first to provide information on arsenic distribution in urban soils of Florida, and the data are useful for assessing arsenic contamination and determining the need for remediation.
Effects of Organic Amendments on the Reduction and Phytoavailability of Chromate in Mineral Soil
Authors: Bolan N. S. , Adriano D. C. , Natesan R. , Koo B.‐J.
Published: August 2012

In this study, seven organic amendments (biosolid compost, farm yard manure, fish manure, horse manure, spent mushroom, pig manure, and poultry manure) were investigated for their effects on the reduction of hexavalent chromium [chromate, Cr(VI)] in a mineral soil (Manawatu sandy soil) low in organic matter content. Addition of organic amendments enhanced the rate of reduction of Cr(VI) to Cr(III) in the soil. At the same level of total organic carbon addition, there was a significant difference in the extent of Cr(VI) reduction among the soils treated with organic amendments. There was, however, a significant positive linear relationship between the extent of Cr(VI) reduction and the amount of dissolved organic carbon in the soil. The effect of biosolid compost on the uptake of Cr(VI) from the soil, treated with various levels of Cr(VI) (0–1200 mg Cr kg−1 soil), was examined with mustard (Brassica juncea L.) plants. Increasing addition of Cr(VI) increased Cr concentration in plants, resulting in decreased plant growth (i.e., phytotoxicity). Addition of the biosolid compost was effective in reducing the phytotoxicity of Cr(VI). The redistribution of Cr(VI) in various soil components was evaluated by a sequential fractionation scheme. In the unamended soil, the concentration of Cr was higher in the organic‐bound, oxide‐bound, and residual fractions than in the soluble and exchangeable fractions. Addition of organic amendments also decreased the concentration of the soluble and exchangeable fractions but especially increased the organic‐bound fraction in soil.
Correlation of Cadmium Distribution Coefficients to Soil Characteristics
Authors: Holm Peter E. , Rootzén Helle , Borggaard Ole K. , M⊘berg Jens Peter , Christensen Thomas H.
Published: August 2012

Cadmium (Cd) distribution between the soil solid phase and the soil solution is a key issue in assessing the environmental effect of Cd in the terrestrial environmental. Previous studies have shown that many individual minerals and other components found in soils can bind Cd, but most studies on whole soil samples have shown that pH is the main parameter controlling the distribution. To identify further the components that are important for Cd binding in soil we measured Cd distribution coefficients (Kd) at two fixed pH values and at low Cd loadings for 49 soils sampled in Denmark. The Kd values for Cd ranged from 5 to 3000 L kg−1 The soils were described pedologically and characterized in detail (22 parameters) including determination of contents of the various minerals in the clay fraction. Correlating parameters were grouped and step‐wise regression analysis revealed that the organic carbon content was a significant variable at both pH values. Cation exchange capacity (CEC) and gibbsite were important at the low pH (5.3) while iron oxides also were important at the high pH (6.7). None of the other clay minerals present in the soils (illite, smectite, kaolinite, hydroxy interlayered clay minerals [HIM], chlorite, quartz, microcline, plagioclase) were significant in explaining the Cd distribution coefficient.
Long‐Term Biosolids Application Effects on Metal Concentrations in Soil and Bermudagrass Forage
Authors: Gaskin Julia W. , Brobst Robert B. , Miller William P. , Tollner E. William
Published: August 2012

The long‐term application of biosolids that periodically contained elevated metal concentrations has raised questions about potential effects on animal health. To address these concerns, we determined metal concentrations (As, Cd, Cu, Pb, Hg, Mo, Ni, Se, and Zn) in both soil and bermudagrass [Cynodon dactylon (L.) Pers.] forage from 10 fields in the following categories of biosolids application: six or more years (>6YR), less than six years (<6YR), and no applications (NS). Soil metal concentrations in all groups were similar to values reported for mineral soils in Georgia, and well below USEPA cumulative limits. Average metal concentrations in the forage were below the maximum tolerable level (MTL) for beef cattle, although two biosolids‐amended fields in the >6YR group produced forage that was at or near the MTL for Cd and Mo, and one field in the <6YR group produced forage above the MTL for Cd. The Cu to Mo ratios in forage decreased with increasing time of sludge application, with the average in the >6YR group at a proposed 5:1 Cu to Mo ratio limit to protect ruminant health. Sulfur concentrations in the forage from all three groups was near the MTL of 4 g kg−1 The study indicated that toxic levels of metals have not accumulated in the soils due to long‐term biosolids application. Overall forage quality from the biosolids‐amended fields was similar to that of commercially fertilized fields; however, due to the relatively high S and potential for a low Cu to Mo ratio, Cu supplements should be used to ensure ruminant health.
In Situ Treatment of Metals in Contaminated Soils with Phytate
Authors: Seaman John C. , Hutchison Jessica M. , Jackson Brian P. , Vulava Vijay M.
Published: August 2012

Batch experiments were conducted to evaluate the ability of various forms of phytate, the hexaphosphoric form of myo‐inositol (IP6), to immobilize U, Ni, and other inorganic contaminants in soils and sediments. A Ca–phytate precipitate (Can–IP6), dodeca sodium–phytate (Na12–IP6), and hydroxyapatite (HA) were added to contaminated soil at rates of 0, 10, 25, and 50 g kg−1 and equilibrated in 0.001 M CaCl2 The samples were then centrifuged, the solution pH was measured, and the supernatants were filtered prior to analysis for dissolved organic carbon (DOC), U, Ni, P, and other inorganic contaminants, such as As, Cr, Se, and Pb. The residual sediments were air‐dried prior to characterization by analytical electron microscopy and extraction with the Toxicity Characteristic Leaching Procedure (TCLP). The solubility of several metals (e.g., U, Pb, Cu) increased with increasing Na12–IP6 when compared with the nonamended control. In some cases immobilization was observed at the lowest Na12–IP6 application rate (10 g kg−1) with an increase in solubility observed at the higher rates, demonstrating the importance of metal to ligand ratio. In contrast, Can–IP6 and HA decreased the solubility of U, Ni, Al, Pb, Ba, Co, Mn, and Zn. For example, soluble U decreased from 2242 to 76 μg kg−1 and Ni from 58 to 9.6 mg kg−1 with the Can–IP6 addition, similar to the results observed for HA. Arsenic and Se solubility increased for HA and both forms of IP6, but to a much greater degree for Na12–IP6, suggesting that the increase in pH observed for HA and Na12–IP6, combined with added competition from PO4 and IP6 for sorption sites, resulted in the release of sorbed oxyanion contaminants. The analytical electron microscopy results indicated that metals such as U and Ni were closely associated with secondary Al‐rich precipitates in the HA‐treated soils, rather than unreacted HA. The analytical electron microscopy results were less definitive for the Can–IP6‐treated soil, although the residual P‐containing material was enriched in Al, with lesser amounts of U and Ni.
Identifying Relationships between Baseflow Geochemistry and Land Use with Synoptic Sampling and R‐Mode Factor Analysis
Authors: Wayland Karen G. , Long David T. , Hyndman David W. , Pijanowski Bryan C. , Woodhams Sarah M. , Haack Sheridan K.
Published: August 2012

The relationship between land use and stream chemistry is often explored through synoptic sampling of rivers at baseflow conditions. However, baseflow chemistry is likely to vary temporally and spatially with land use. The purpose of our study is to examine the usefulness of the synoptic sampling approach for identifying the relationship between complex land use configurations and stream water quality. This study compares biogeochemical data from three synoptic sampling events representing the temporal variability of baseflow chemistry and land use using R‐mode factor analysis. Separate R‐mode factor analyses of the data from individual sampling events yielded only two consistent factors. Agricultural activity was associated with elevated levels of Ca2+, Mg2+, alkalinity, and frequently K+, SO2−4, and NO−3 Urban areas were associated with higher concentrations of Na+, K+, and Cl− Other retained factors were not consistent among sampling events, and some factors were difficult to interpret in the context of biogeochemical sources and processes. When all data were combined, further associations were revealed such as an inverse relationship between the proportion of wetlands and stream nitrate concentrations. We also found that barren lands were associated with elevated sulfate levels. This research suggests that an individual sampling event is unlikely to characterize adequately the complex processes controlling interactions between land use and stream chemistry. Combining data collected over two years during three synoptic sampling events appears to enhance our ability to understand processes linking stream chemistry and land use.
Stable Carbon Isotope Ratio and Composition of Microbial Fatty Acids in Tropical Soils
Authors: Burke Roger A. , Molina Marirosa , Cox Julia E. , Osher Laurie J. , Piccolo Marisa C.
Published: August 2012

The soil microbial community plays a critical part in tropical ecosystem functioning through its role in the soil organic matter (SOM) cycle. This study evaluates the relative effects of soil type and land use on (i) soil microbial community structure and (ii) the contribution of SOM derived from the original forest vegetation to the functioning of pasture and sugarcane (Saccharum spp.) ecosystems. We used principal components analysis (PCA) of soil phospholipid fatty acid (PLFA) profiles to evaluate microbial community structure and PLFA stable carbon isotope ratios (δ13C) as indicators of the δ13C of microbial substrates. Soil type mainly determined the relative proportions of Gram positive versus Gram negative bacteria whereas land use primarily determined the relative proportion of fungi, protozoa, and actinomycetes versus other types of microorganisms. Comparison of a simple model to our PLFA δ13C data from land use chronosequences indicates that forest‐derived SOM is actively cycled for appreciably longer times in sugarcane ecosystems developed on Andisols (mean turnover time = 50 yr) than in sugarcane ecosystems developed on an Oxisol (mean turnonver time = 13 yr). Our analyses indicate that soil chronosequence PLFA δ13C measurements can be useful indicators of the contribution that SOM derived from the original vegetation makes to continued ecosystem function under the new land use.
Persistent Organic Pollutants in the Environment
Authors: Lee Wen‐Yee , Iannucci‐Berger William , Eitzer Brian D. , White Jason C. , Incorvia Mattina MaryJane
Published: August 2012

The half‐lives of some persistent organic pollutants (POPs) in environmental compartments such as soil and air can be as long as decades. In spite of the hydrophobicity of many POPs, the literature contains reports of their uptake by, and translocation through, a variety of plants. Both these observations prompt the investigation of whether a vegetation‐based environmental compartment such as compost contains significant residues of POPs. Previous reports imply that residues of technical chlordane will be found in compost. Due to its physicochemical properties, technical chlordane provides insights into the fate of POPs in the environment, which are not accessible through determinations of other pollutants in this group. Accordingly, we undertook the first comprehensive examination of technical chlordane residues in a variety of composts, specifically, 13 commercial and 39 municipal compost products, to both characterize and quantify the magnitude of this point source of contamination. Using chiral gas chromatography interfaced to ion trap mass spectrometry, the concentration and the compositional and enantiomeric profiles of chlordane components were determined. Of the 13 commercial products, 9 contained detectable chlordane concentrations, ranging from 4.7 to 292 μg/kg (dry wt.), while all 39 municipal products contained chlordane residues ranging from 13.9 to 415 μg/kg (dry wt.). The residue concentrations and profiles suggest possible feedstock sources for the chlordane in the finished compost product. The data also support the conclusion that some composts contribute to anthropogenic cycling of POPs through the biosphere.
Greenhouse Gas Emissions and Soil Indicators Four Years after Manure and Compost Applications
Authors: Ginting Daniel , Kessavalou Anabayan , Eghball Bahman , Doran John W.
Published: August 2012

Understanding how carbon, nitrogen, and key soil attributes affect gas emissions from soil is crucial for alleviating their undesirable residual effects that can linger for years after termination of manure and compost applications. This study was conducted to evaluate the emission of soil CO2, N2O, and CH4 and soil C and N indicators four years after manure and compost application had stopped. Experimental plots were treated with annual synthetic N fertilizer (FRT), annual and biennial manure (MN1 and MN2, respectively), and compost (CP1 and CP2, respectively) from 1992 to 1995 based on removal of 151 kg N ha−1 yr−1 by continuous corn (Zea mays L.). The control (CTL) plots received no input. After 1995, only the FRT plots received N fertilizer in the spring of 1999. In 1999, the emissions of CO2 were similar between control and other treatments. The average annual carbon input in the CTL and FRT plots were similar to soil CO2–C emission (4.4 and 5.1 Mg C ha−1 yr−1, respectively). Manure and compost resulted in positive C and N balances in the soil four years after application. Fluxes of CH4–C and N2O‐N were nearly zero, which indicated that the residual effects of manure and compost four years after application had no negative influence on soil C and N storage and global warming. Residual effects of compost and manure resulted in 20 to 40% higher soil microbial biomass C, 42 to 74% higher potentially mineralizable N, and 0.5 unit higher pH compared with the FRT treatment. Residual effects of manure and compost on CO2, N2O, and CH4 emissions were minimal and their benefits on soil C and N indicators were more favorable than that of N fertilizer.
Molecular‐Level Investigation of Monoaromatic Compound Sorption to Suspended Soil Particles by Deuterium Nuclear Magnetic Resonance
Authors: Zhu Dongqiang , Herbert Bruce E. , Schlautman Mark A.
Published: August 2012

Molecular‐level sorption behavior of monoaromatic compounds in suspensions of water‐dispersable clay components was studied by measuring 2H nuclear magnetic resonance (NMR) spin–spin relaxation times (T2). In general, decreased T2 values indicate stronger solute–sorbent interactions and increased sorption of the solute. A decreasing trend for T2 values in the order benzene > fluorobenzene > toluene (‐C6D5 moiety) was observed, which was probably caused by the hydrophobic effect. The T2 values for benzene and the ‐C6D5 moiety of toluene increased with increasing pH, whereas the trend with pH was much weaker and less consistent for fluorobenzene and the methyl group of toluene. Conversely, no clear relationship was found between T2 values and pH for dichloromethane. These contrasting results cannot be explained by the pH‐dependent self‐assembly and hydrophobicity of humics. Instead, directed specific forces, including hydrogen bonding, cation–π interactions, and aromatic–aromatic interactions, are proposed between the benzene ring of monoaromatic solutes and soil organic matter (SOM). Substituents of benzene affect these interactions by varying the π electron density. When the soil fraction was treated with NaOH to remove humic and fulvic acids, T2 values for the different monoaromatic solutes were surprisingly lower compared with those for the untreated soil fraction. This result is probably caused by the increased ratio of solutes adsorbed to “hard” or “glassy” SOM components, which leads to less mobile sorbed solute molecules, after removing NaOH‐extractable humics that contain more “soft” or “rubbery” SOM components.
Sorption and Desorption of Naphthalene by Soil Organic Matter
Authors: Gunasekara Amrith S. , Xing Baoshan
Published: August 2012

Nonlinear isotherm behavior has been reported for the sorption of hydrophobic organic compounds (HOCs) in soil organic matter (SOM), but the exact mechanisms are unknown. Our objective was to provide insight into the sorption mechanism of HOCs in SOM by studying the sorption–desorption processes of naphthalene in a mineral soil, its humic fractions, and lignin. Additionally, humin and lignin were used for studying the effects of temperature and cosolvent on HOC sorption. All isotherms were nonlinear. The humin and lignin isotherms became more linear at elevated temperatures and with the addition of methanol indicating a condensed to expanded structural phase transition. Isotherm nonlinearity and hysteresis increased in the following order: soil humic acid (HA) < soil < soil humin. Of the samples, aliphatic‐rich humin exhibited the largest degree of nonlinearity and had the highest sorption capacity for naphthalene. High nonlinearity and hysteresis in humin were most likely caused by its condensed structure. A novel aliphatic, amorphous condensed conformation is proposed. This conformation can account for both high sorption capacities and increased nonlinearity observed for aliphatic‐rich samples and can explain many sorption disparities discussed in the literature. This study clearly illustrates the importance of both aliphatic and aromatic moieties for HOC sorption in SOM.
Integrated BIosphere Simulator (IBIS) Yield and Nitrate Loss Predictions for Wisconsin Maize Receiving Varied Amounts of Nitrogen Fertilizer
Authors: Kucharik Christopher J. , Brye Kristofor R.
Published: August 2012

Agriculture in the U.S. Midwest faces the formidable challenge of improving crop productivity while simultaneously mitigating the environmental consequences of intense management. This study examined the simultaneous response of nitrate nitrogen (NO3–N) leaching losses and maize (Zea mays L.) yield to varied fertilizer N management using field observations and the Integrated BIosphere Simulator (IBIS) model. The model was validated against six years of field observations in chisel‐plowed maize plots receiving an optimal (180 kg N ha−1) fertilizer N application and in N‐unfertilized plots on a silt loam soil near Arlington, Wisconsin. Predicted values of grain yield, harvest index, plant N uptake, residue C to N ratio, leaf area index (LAI), grain N, and drainage were within 20% of observations. However, simulated NO3–N leaching losses, NO3–N concentrations, and net N mineralization exhibited less interannual variability than observations, and had higher levels of error (20–65%). Potential effects of 30% higher (234 kg N ha−1) and 30% lower (126 kg N ha−1) fertilizer N use (from optimal) on NO3–N leaching loss and maize yield were simulated. A 30% increase in fertilizer N use increased annual NO3–N leaching by 56%, while yield increased by only 1%. The NO3–N concentration in the leachate solution at 1.4 m below the soil surface was 30.7 mg L−1 When fertilizer N use was reduced by 30% (from optimal), annual NO3–N leaching losses declined by 42% after seven years, and annual average yield only decreased by 8%. However, NO3–N concentration in the leachate solution remained above 10 mg L−1 (11.3 mg L−1). Clearly, nonlinear relationships existed between changes in fertilizer use and NO3–N leaching losses over time. Simulated changes in NO3–N leaching were greater in magnitude than fertilizer N use changes.
Methane Emissions of Beef Cattle on Forages
Authors: DeRamus H. Alan , Clement Terry C. , Giampola Dean D. , Dickison Peter C.
Published: August 2012

Fermentation in the rumen of cattle produces methane (CH4). Methane may play a role in global warming scenarios. The linking of grazing management strategies to more efficient beef production while reducing the CH4 emitted by beef cattle is important. The sulfur hexafluoride (SF6) tracer technique was used to determine the effects of best management practices (BMP) grazing compared with continuous grazing on CH4 production in several Louisiana forages during 1996–1998. Cows and heifers (Bos taurus) grazed common bermudagrass [Cynodon dactylon (L.) Pers.], bahiagrass (Paspalum notatum Flugge), and ryegrass (Lolium multiflorum Lam.) pastures and were wintered on bahiagrass hay with supplements of protein molasses blocks (PMB), cottonseed meal and corn (CSMC), urea and corn (URC), or limited ryegrass grazing (LRG). Daily CH4 emissions were between 89 and 180 g d−1 for young growing heifers and 165 to 294 g d−1 for mature Simbrah cows. Heifers on “ad lib” ryegrass in March and April produced only one‐tenth the CH4 per kg of gain as heifers on LRG of 1 h. Using BMP significantly reduced the emission of CH4 per unit of animal weight gain. Management‐intensive grazing (MIG) is a BMP that offers the potential for more efficient utilization of grazed forage crops via controlled rotational grazing and more efficient conversion of forage into meat and milk. Projected CH4 annual emissions in cows reflect a 22% reduction from BMP when compared with continuous grazing in this study. With the BMP application of MIG, less methane was produced per kilogram of beef gain.
Evaluation of Attachment ofCryptosporidium parvumandGiardia lambliato Soil Particles
Authors: Dai Xin , Boll Jan
Published: August 2012

Transport ofCryptosporidium parvumoocysts andGiardia lambliacysts in the aquatic environment is poorly understood. Information about their transport is essential for actual risk assessment and development of effective control practices. Several studies have suggested that attachment to soil particles is not likely to occur, but the hypothesis has not been well tested, partly because enumeration ofC. parvumoocysts orG. lambliacysts [written as (oo)cysts] in the presence of soil has been difficult. In this paper, a combination of flow cytometry, and epifluorescence and confocal microscopy was successfully used to enumerate (oo)cysts in the presence of soil and determine whether (oo)cysts travel freely in water or attached to soil particles. The maximum soil concentration in water samples for reliable enumeration of (oo)cysts was 2 mg/L. Particle attachment experiments detected attached pairs of oppositely charged beads and (oo)cysts, while no attachment was observed between like charged beads, (oo)cysts, and soil particles. These results support the hypothesis that electrostatic forces govern the interaction between (oo)cysts and soil particles. Batch experiments further confirmed the null hypothesis (p> 0.05) that (oo)cysts do not attach to natural soil particles. These findings suggest that, when (oo)cysts have been entrained in overland flow (i.e., runoff), they will travel freely in the water and not as part of the particulate sediment load.