bluuebunny/crossref_metadata_2025 huggingface dataset:
Aerating Grasslands
Authors: Franklin D. H. , Cabrera M. L. , West L. T. , Calvert V. H. , Rema J. A.
Published: January 2007

Aeration has been promoted as improving infiltration of rainfall and extending grass or forage productivity, but research on the impact of this practice on P losses from grasslands has had mixed results. We designed a study to determine at the field scale, using a paired watershed approach, the impact of slit aeration on runoff volume and P losses in runoff from fescue (Festuca arundinaceaSchreb.)/bermudagrass (Cynodon dactylonL.) hay fields fertilized with broiler litter. Three pairs of 0.8‐ha fields, each with similar soils (Typic Kanhapludults, Aquic Hapludults, and Aquultic Hapludalfs), were fertilized with broiler litter and monitored under similar management from 1995 through 1998, then one field in each pair received aeration treatment from 2001 through 2003. In the field with mostly well‐drained soils, grassland aeration reduced surface runoff volume and mass losses of dissolved reactive P (DRP) in runoff by approximately 35%. In contrast, when poorly drained soils dominated, grassland aeration increased runoff volume (4.8 mm/runoff event) and mass losses of DRP and total P (0.25 kg TP ha−1per runoff event). This implies that aeration of well‐drained soils in the top poultry‐producing counties of Georgia (0.2 million ha) could decrease dissolved phosphorus losses by more than 500 Mg P each year. This is not the case if soils are poorly drained.
Relative Effects of Land Use and Near‐Stream Chemistry on Phosphorus in an Urban Stream
Authors: Sonoda Kazuhiro , Yeakley J. Alan
Published: January 2007

Elevated levels of P in urban streams can pose significant water quality problems. Sources of P in urban streams, however, are difficult to identify. It is important to recognize both natural and anthropogenic sources of P. We investigated near‐stream chemistry and land use factors on stream water P in the urbanizing Johnson Creek watershed in Portland, OR, USA. We sampled stream water and shallow groundwater soluble reactive P (SRP) and total P (TP) and estimated P flux at 13 sites along the main stem of Johnson Creek, with eight sites in urban land use areas and five sites in nonurban land use areas. At each site, we sampled the A and B horizons, measuring soil pH, water‐soluble P, acid‐soluble P, base‐soluble P, total P, Fe, and Al. We found continuous input of P to the stream water via shallow groundwater throughout the Johnson Creek watershed. The shallow groundwater P concentrations were correlated with stream water P within the nonurban area; however, this correlation was not found in the urban area, suggesting that other factors in the urban area masked the relationship between groundwater P and stream water P. Aluminum and Fe concentrations were inversely correlated with shallow groundwater P, suggesting that greater P adsorption to Al and Fe oxides in the nonurban area reduced availability of shallow groundwater P. Using stepwise multiple regression analysis, however, we concluded that while riparian soil chemistry was related to stream water P, land use patterns had a more significant relationship with stream water P concentrations in this urbanizing system.
Influence of Soil pH and Application Rate on the Oxidation of Calcium Sulfite Derived from Flue Gas Desulfurization
Authors: Lee Y. B. , Bigham J. M. , Dick W. A. , Jones F. S. , Ramsier C.
Published: January 2007

Calcium sulfite hemihydrate (CaSO3·0.5H2O), a common byproduct of coal‐fired utilities, is fairly insoluble and can decompose to release toxic SO2under highly acidic soil conditions; however, it can also oxidize to form gypsum. The objective of this study was to examine the effects of application rate and soil pH on the oxidation of calcium sulfite under laboratory conditions. Oxidation rates measured by release of SO4–S to solution decreased with increasing application rate. Leachate SO4–S from soils amended with 1.0 to 3.0 g kg−1CaSO3increased over a 21 to 28 d period before reaching a plateau. At 4 g kg−1, maximum SO4–S release was delayed until Week 7. Oxidation and release of SO4–S from soil amended with 3.0 g kg−1calcium sulfite increased markedly with decreasing soil pH. After only 3 d incubation, the concentrations of SO4–S in aqueous leachates were 77, 122, 170, 220, and 229 mg L−1for initial soil pH values of 7.8, 6.5, 5.5, 5.1, and 4.0, respectively. At an initial soil pH value of 4.0, oxidation/dissolution did not increase much after 3 d. At higher pH values, oxidation was maximized after 21 d. These results suggest that autumn surface applications of calcium sulfite in no‐till systems should permit ample time for oxidation/dissolution reactions to occur without introducing biocidal effects related to oxygen scavenging. Soil and annual crops can thus benefit from additions of soluble Ca and SO4if calcium sulfite is applied in advance of spring planting.
Surface Seals Reduce 1,3‐Dichloropropene and Chloropicrin Emissions in Field Tests
Authors: Gao Suduan , Trout Thomas J.
Published: January 2007

Reducing emissions is essential for minimizing the impact of soil fumigation on the environment. Water application to the soil surface (or water seal) has been demonstrated to reduce 1,3‐dichloropropene (1,3‐D) emissions in soil column tests. This study determined the effectiveness of water application to reduce emissions of 1,3‐D and chloropicrin (CP) in comparison to other surface seals under field conditions. In a small‐plot field trial on a Hanford sandy loam soil (coarse‐loamy, mixed, superactive, nonacid, thermic Typic Xerorthents) in the San Joaquin Valley, CA. Telone C35 (61% 1,3‐D and 35% CP) was shank‐applied at a depth of 46 cm at a rate of 610 kg ha−1 Soil surface seal treatments included control (no tarp and no water application), standard high density polyethylene (HDPE) tarp over dry and pre‐irrigated soil, virtually impermeable film (VIF) tarp, initial water application by sprinklers immediately following fumigation, and intermittent water applications after fumigation. The atmospheric emissions and gas‐phase distribution of fumigants in soil profile were monitored for 9 d. Among the surface seals, VIF and HDPE tarp over dry soil resulted in the lowest and the highest total emission losses, respectively. Intermittent water applications reduced 1,3‐D and CP emissions significantly more than HDPE tarp alone. The initial water application also reduced emission peak and delayed emission time. Pre‐irrigated soil plus HDPE tarp reduced fumigant emissions similarly as the intermittent water applications and also yielded the highest surface soil temperature, which may improve overall soil pest control.
Effects of Tree Root‐Derived Substrates and Inorganic Nutrients on Pyrene Mineralization in Rhizosphere and Bulk Soil
Authors: Mueller Kevin E. , Shann Jodi R.
Published: January 2007

This study investigated the effects of organic and inorganic nutrients on the microbial degradation of the common soil contaminant pyrene. The material used in this investigation was collected from potted trees that had been growing for over a year in a soil artificially contaminated with polycyclic aromatic hydrocarbons. Soil was removed from the nonroot (bulk) and root (rhizosphere) zones of these pots and used in mineralization studies that tracked microbial degradation of 14C‐pyrene. The factors influencing degradation in these zones were then tested by amendment with essential inorganic nutrients or with root‐derived materials. As expected, pyrene mineralization was greater in soil removed from the rhizosphere than in bulk soil. The rate of mineralization in rhizosphere soil was inhibited by inorganic nutrient amendment, whereas nutrients stimulated mineralization in the bulk soil. Pyrene mineralization in bulk soil was also increased by the addition of root extracts intended to mimic exudation by living roots. However, amendment with excised fine roots that were allowed to decay over time in soil initially inhibited mineralization. With time, the rate of mineralization increased, eventually exceeding that of unamended bulk soil. Combined, the initial inhibition and subsequent stimulation produced a zero net impact of decaying fine roots on bulk soil mineralization. Our results, in conjunction with known temporal patterns of fine root dynamics in natural systems, support the idea that seasonal variations in nutrient and substrate availability may influence the long‐term effect of plants on organic degradation in soil, possibly reducing or negating the beneficial effects of vegetation that are often observed in short‐term studies.
Influence of Decomposition on Chemical Properties of Plant‐ and Manure‐Derived Dissolved Organic Matter and Sorption to Goethite
Authors: Hunt James F. , Ohno Tsutomu , He Zhongqi , Honeycutt C. Wayne , Dail D. Bryan
Published: January 2007

Sorption of dissolved organic matter (DOM) plays an important role in maintaining the fertility and quality of soils in agricultural ecosystems. Few studies have examined the effects of decomposition on DOM sorption and chemical characteristics. This study investigated the sorption to goethite (α‐FeOOH) of fresh and decomposed hydrophilic (HPL) and hydrophobic (HPB) DOM fractions extracted from the shoots and roots of crimson clover (Trifolium incarnatum L.), corn (Zea mays L.), soybean [Glycine max (L.) Merr.], hairy vetch (Vicia villosa L.), and dairy and poultry manures. Sorption was positively related to apparent molecular weight (MWAP), aromaticity as measured by absorptivity at 280 nm, and phenolic acid content. A 10‐d laboratory microbial decomposition of the source organic matter generally increased the sorption of the extracted DOM onto goethite. The decomposition effect on sorption was greater for the HPL fractions than for the HPB fractions. There was a decrease in the MWAP values of the DOM samples following sorption to goethite. In many cases the reduction in MWAP was large, indicating a strong preference by goethite for the higher MWAP DOM fractions. The results of this laboratory‐based research demonstrate that microbial processes affect the chemical characteristics of DOM which may affect the distribution of soil organic C pools.
Single‐Element and Competitive Metal Mobility Measured with Column Infiltration and Batch Tests
Authors: Antoniadis Vasileios , McKinley John D. , Zuhairi Wan Y. W.
Published: January 2007

The distribution coefficient, Kd, is often used to quantify heavy metal mobility in soils. Batch sorption or column infiltration tests may be used to measure Kd The latter are closer to natural soil conditions, but are difficult to conduct in clays. This difficulty can be overcome by using a laboratory centrifuge. An acceleration of 2600 gravities was applied to columns of London Clay, an Eocene clay sub‐stratum, and Cu, Ni, and Zn mobility was measured in centrifuge infiltration tests, both as single elements and in dual competition. Single‐element Kd values were also obtained from batch sorption tests, and the results from the two techniques were compared. It was found that Kd values obtained by batch tests vary considerably depending on the metal concentration, while infiltration tests provided a single Kd value for each metal. This was typically in the lower end of the range of the batch test Kd values. For both tests, the order of mobility was Ni > Zn > Cu. Metals became more mobile in competition than when in single‐element systems: Ni Kd decreased 3.3 times and Zn Kd 3.4 times when they competed with Cu, while Cu decreased only 1.2 times when in competition with either Ni or Zn. Our study showed that competitive sorption between metals increases the mobility of those metals less strongly bound more than it increases the mobility of more strongly bound metals.
Denitrification Potential and Organic Matter as Affected by Vegetation Community, Wetland Age, and Plant Introduction in Created Wetlands
Authors: Hernandez Maria E. , Mitsch William J.
Published: January 2007

Denitrification potential (DP) and organic matter (OM) in soils were compared in three different vegetation communities—emergent macrophyte, open water, and forested edge—in two 10‐yr‐old created riverine wetlands. Organic matter, cold water‐extractable organic matter (CWEOM), anaerobic mineralizable carbon (AnMC), and DP varied significantly (P< 0.05) among vegetation communities. The surface (0 to 9 cm) soils in the emergent macrophyte community (EMC) showed highest DP (0.07 ± 0.01 mg N h−1kg−1), OM (84.90 ± 5.60 g kg−1), CWEOM (1.12 ± 0.20 g kg−1), and AnMC (1.50 ± 0.10 mg C h−1kg−1). In the deeper layer (9 to 18 cm), DP and CWEOM (0.04 ± 0.01 mg N h−1kg−1and 1.13 ± 0.20 g kg−1, respectively) were significantly higher in the open water community (OWC) than in the emergent macrophyte and forested edge communities. Plant introduction did not affect DP or OM content and characteristics. After 10 yr of wetland development, mean DP increased 25‐fold in the surface layer (from 0.002 to 0.053 mg N h−1kg−1); OM content more than doubled to 90.80 ± 19.22 g kg−1, and CWEOM and HWEOM increased 2.5 and 2.7 times respectively from 1993 (prewetland conditions) to 2004. Humic acids were the most abundant form of OM in 2004 and 1993 samples. Significant (P< 0.05) positive relationships between DP and OM, CWEOM, and AnMC were found in the surface layer; in the 9‐ to 18‐cm layer, significant positive relationships were found between DP and CWEOM and AnMC.
Improving the Accuracy of Sediment‐Associated Constituent Concentrations in Whole Storm Water Samples by Wet‐Sieving
Authors: Selbig William R. , Bannerman Roger , Bowman George
Published: January 2007

Sand‐sized particles (>63 μm) in whole storm water samples collected from urban runoff have the potential to produce data with substantial bias and/or poor precision both during sample splitting and laboratory analysis. New techniques were evaluated in an effort to overcome some of the limitations associated with sample splitting and analyzing whole storm water samples containing sand‐sized particles. Wet‐sieving separates sand‐sized particles from a whole storm water sample. Once separated, both the sieved solids and the remaining aqueous (water suspension of particles less than 63 μm) samples were analyzed for total recoverable metals using a modification of USEPA Method 200.7. The modified version digests the entire sample, rather than an aliquot, of the sample. Using a total recoverable acid digestion on the entire contents of the sieved solid and aqueous samples improved the accuracy of the derived sediment‐associated constituent concentrations. Concentration values of sieved solid and aqueous samples can later be summed to determine an event mean concentration.
Assessment of Water Quality and Identification of Pollution Sources of Plateau Lakes in Yunnan (China)
Authors: Li Renqiang , Dong Ming , Zhao Yang , Zhang Lili , Cui Qingguo , He Weiming
Published: January 2007

The plateau lakes of Yunnan are important both ecologically and economically in China. Nevertheless, the human impact on water quality in these lakes has become increasingly highlighted. The water quality of 10 plateau lakes was monitored regularly over the period of 2000 through 2004 for 24 parameters. Multivariate statistical techniques, including cluster analysis (CA), factor analysis (FA), and principal component analysis (PCA), were employed to better interpret information about the water quality and its pollution sources. No obvious data reduction from CA/FA was found because three principal components (PCs) needed 14 variables to explain 85.01% of the total variance. However, three latent factors accounted for pollution mainly from the following sources: agricultural activities, residential activities and anthropogenic‐toxic pollution from industrial effluents, or other special activities. Box‐whiskers plots were employed to visually interpret the spatiotemporal variations of water quality variables, which were highly correlated with three PCs. Three types of water quality (i.e., low‐, medium‐, and high‐polluted lakes) were determined through CA based on the similarity of water quality variables. Our results may provide helpful information for the authorities to effectively manage the water quality and make sound policies.
Phosphorus Leaching from Cow Manure Patches on Soil Columns
Authors: Chardon W. J. , Aalderink G. H. , van der Salm C.
Published: January 2007

The loss of P in overland flow or leachate from manure patches can impair surface water quality. We studied leaching of P from 10‐cm‐high lysimeters filled with intact grassland soil or with acid‐washed sand. A manure patch was created on two grassland and two sand‐filled lysimeters, and an additional two grass lysimeters served as blanks. Lysimeters were leached in the laboratory during 234 d with a diluted salt solution, and column effluent was passed through a 0.45‐μm filter, analyzed for pH, dissolved reactive P (DRP), and total dissolved P (TDP). At the end of the experiment lysimeter soil was sampled and analyzed for pH, available P, and oxalate‐extractable P, Fe, and Al. The concentration of TDP in the effluent from the sand column increased to 25 mg L−1 during the first weeks and remained above 10 mg L−1 during the rest of the percolation. In effluent from grass + patch lysimeters TDP gradually increased to 4 mg L−1 Both in the manure and in the effluent of the sand lysimeter P was found mainly in the form of DRP, but in the effluent from the grass lysimeters was found mainly as dissolved unreactive P (DUP = TDP − DRP). Earthworm activity was responsible for decomposition of the manure patch on the grass lysimeters. Manure patches and their remains were found to be a long‐term source of high concentrations of P in leachates. Spreading of patches after a grazing period could reduce their possible negative impacts on the environment.
Organic Agriculture and Nitrous Oxide Emissions at Sub‐Zero Soil Temperatures
Authors: Phillips Rebecca L.
Published: January 2007

In the Red River Valley of the upper midwestern United States, soil temperatures often remain below freezing during winter and N2O emissions from frozen cropland soils is assumed to be negligible. This study was conducted to determine the strength of N2O emissions and denitrification when soil temperatures were below zero for a manure‐amended, certified organic field (T2O) compared with an unamended, conventionally managed field (T2C). Before manure application, both fields were similar with respect to autotrophic and heterotrophic N2O production and N2O flux at the soil surface (0.15 ± 0.05 mg N2O–N m−2 d−1 for T2O and 0.12 ± 0.06 mg N2O–N m−2 d−1 for T2C). After application of pelletized, dehydrated manure, average daily flux (based on time‐integrated fluxes from 20 November to 8 April), was 1.19 ± 0.34 mg N2O–N m−2 d−1 for T2O and 0.47 ± 0.37 mg N2O–N m−2 d−1 for T2C. Denitrification for intact cores measured in the laboratory at −2.5°C was greater for organically managed soils, although only marginally significant (p < 0.1). Cumulative emissions for all winter measurements (from 16 November to 8 April) averaged 1.63 kg N2O–N ha−1 for T2O and 0.64 kg N2O–N ha−1 for T2C. Biological N2O production was evident at sub‐zero soil temperatures, with winter emissions exceeding those measured in late summer. Late autumn manure application enhanced cumulative N2O–N emissions by 0.9 kg ha−1
A Model for Phosphorus Transformation and Runoff Loss for Surface‐Applied Manures
Authors: Vadas P. A. , Gburek W. J. , Sharpley A. N. , Kleinman P. J. A. , Moore P. A. , Cabrera M. L. , Harmel R. D.
Published: January 2007

Agricultural P transport in runoff is an environmental concern. An important source of P runoff is surface‐applied, unincorporated manures, but computer models used to assess P transport do not adequately simulate P release and transport from surface manures. We developed a model to address this limitation. The model operates on a daily basis and simulates manure application to the soil surface, letting 60% of manure P infiltrate into soil if manure slurry with less than 15% solids is applied. The model divides manure P into four pools, water‐extractable inorganic and organic P, and stable inorganic and organic P. The model simulates manure dry matter decomposition, and manure stable P transformation to water‐extractable P. Manure dry matter and P are assimilated into soil to simulate bioturbation. Water‐extractable P is leached from manure when it rains, and a portion of leached P can be transferred to surface runoff. Eighty percent of manure P leached into soil by rain remains in the top 2 cm, while 20% leaches deeper. This 2‐cm soil layer contributes P to runoff via desorption. We used data from field studies in Texas, Pennsylvania, Georgia, and Arkansas to build and validate the model. Validation results show the model accurately predicted cumulative P loads in runoff, reflecting successful simulation of the dynamics of manure dry matter, manure and soil P pools, and storm‐event runoff P concentrations. Predicted runoff P concentrations were significantly related to (r2 = 0.57) but slightly less than measured concentrations. Our model thus represents an important modification for field or watershed scale models that assess P loss from manured soils.
Fire Effects on Stable Isotopes in a Sierran Forested Watershed
Authors: Saito Laurel , Miller Wally W. , Johnson Dale W. , Qualls Robert G. , Provencher Louis , Carroll Erin , Szameitat Peter
Published: January 2007

This study tested the hypothesis that stable C and N isotope values in surface soil and litter would be increased by fire due to volatilization of lighter isotopes. The hypothesis was tested by: (1) performing experimental laboratory burns of organic and mineral soil materials from a watershed at combinations of temperature ranging 100 to 600°C and duration ranging from 1 to 60 min; (2) testing field samples of upland soils before, shortly after, and 1 yr following a wildfire in the same watershed; and (3) testing field soil samples from a down‐gradient ash/sediment depositional area in a riparian zone following a runoff event after the wildfire. Muffle furnace results indicated the most effective temperature range for using stable isotopes for tracing fire impacts is 200 to 400°C because lower burn temperatures may not produce strong isotopic shifts, and at temperatures ≥600°C, N and C content of residual material is too low. Analyses of field soil samples were inconclusive: there was a slightly significant effect of the wildfire on δ15N values in upland watershed analyses 1 yr postburn, while riparian zone analyses results indicated that δ13C values significantly decreased ∼0.71‰ over a 9 mo post‐fire period (p = 0.015), and ash/sediment layer δ13C values were ∼0.65‰ higher than those in the A horizon. The lack of field confirmation may have been due to overall wildfire burn temperatures being <200°C and/or microbial recovery and vegetative growth in the field. Thus, the muffle furnace experiment supported the hypothesis, but it is as yet unconfirmed by actual wildfire field data.
Application of Two Organic Wastes in a Soil Polluted by Lead
Authors: Tejada M. , Hernandez M. T. , Garcia C.
Published: January 2007

The effects of adding a crushed cotton gin compost (CCGC) and a poultry manure (PM) on the enzymatic activities of a Typic Xerofluvent soil polluted with Pb were studied in the laboratory. Three hundred grams of sieved soil (<2 mm) were mixed with PM at a rate of 10% or CCGC at a rate of 17.2%, applying to the soil the same amount of organic matter with each organic amendment. Urease, protease‐BBA, β‐glucosidase, alkaline phosphatase, and arylsulfatase activities were measured at four different incubation times (1, 7, 15, and 45 d) in soils containing seven concentrations (100, 250, 500, 1000, 2500, 5000, and 8000 mg kg−1) of Pb, and in the same soils amended with CCGC and PM. In all treatments and incubation times, the inhibition percentage of soil enzyme activities by Pb was lower in soils amended with the PM and CCGC than in nonamended soils, and it differed with the organic amendment. In this respect, the in the 8000 mg Pb kg−1 treatment at the end of the incubation period, the protease‐BBA activity inhibition percentage was lower (14.7 and 33.9% lower, respectively) in CCGC‐ than in PM‐amended soils. Since the adsorption capacity of Pb was higher in CCGC‐ than the PM‐amended soils, the addition of organic wastes with higher humic acid concentration is more beneficial for remediation of soils polluted with Pb.
Battery Farming or Free Ranging: Towards Citizen Participation in E-Learning Environments
Authors: Hall Richard
Published: January 2007

This article presents a model for conceptualising learner involvement in online environments. It takes as its starting point the emerging approach to service-user engagement in public-sector change in the United Kingdom. This is focused upon civic inclusion and empowered decision making. In turn this personalisation is related to issues surrounding information literacy and access to technology, in order to frame a structure for legitimate participation in e-environments. However, a key question is whether more controlled, academic environments can be activated for use by learners, and if so, what types of participative involvement are created and valued. Thus, a model for participation is developed, which captures how academic teams can move towards partnership and co-ownership with students. This focuses upon building an e-learning approach that is responsive and inclusive, and which has a ‘free-ranging’ structure that demands the legitimate participation of learners as co-owners of its environmental definition. The evaluation uses an action research-based approach to assess how academic staff can work with students to activate meaningful online spaces.
How Learning Styles Impact E-Learning: A Case Comparative Study of Undergraduate Students Who Excelled, Passed, or Failed an Online Course in Scientific/Technical Writing
Authors: West William , Rosser B.R. Simon , Monani Salma , Gurak Laura
Published: January 2007

Online classes appear increasingly popular, making it critical in each discipline to study the advantages and disadvantages of learning online. Following up on anecdotal impressions that scientific/technical writing students appeared to do either better or worse in an online course than an offline equivalent (unpublished data), it was decided to study the impact of learning style and experience in using the Internet on grades. The 60 students who participated in an online course on scientific/technical writing were emailed post-course evaluations which included questions on learning styles. Of these, 37 (62%) returned the evaluations, revealing a clear and significant pattern of results. While the groups did not differ in hours spent studying online, or in total hours spent online, students who excelled in online learning reported spending significantly more hours per week online for work, and less hours online contacting families/friends than students who passed or students who failed. Students who excelled differed significantly from other students in their learning strategies and study habits and frequency with which they contacted the instructor. Students who excelled in this online class appear more experienced both in working online and have study habits conducive to the online environment. Curiously, students who performed marginally or failed were more likely to rate themselves as making good use of study time, and may spend significantly longer online on assignments than the moderate students. The need to design courses that elicit specific habits or to teach students study habits specific to online learning appear critical tasks to improve the success and retention rates in online courses.
The Limits of ‘Blackboard’ are the Limits of My World: On the Changing Concepts of the University and its Students
Authors: Lambeir Bert , Ramaekers Stefan
Published: January 2007

This article focuses on the changing concepts of the university student and teacher, of learning and teaching, and of the university as such because of the use and integration of electronic learning environments. This mode of digital learning implies important changes in established practices in which students and teachers inevitably take part. Hitherto familiar practices are at stake. The way we understand these changing practices suggests that the implementation of the digital learning environment encompasses more than just a mere instrumental change in the processes of teaching and learning. What at first sight only seems to be a simple material intervention puts a number of familiar concepts and noble intentions under stress. Without wanting to decline the use of information and communications technology in higher education, the authors argue that it is far from self-evident to accept an electronic learning environment as effectively supporting a student's self-tuition, or as stimulating learning as a critical and sustained activity.
Can Organisational Vision Be Aligned to Management Processes for Engaging with E-Learning? A Case Study for a Recasting Dialogue as Central to Infrastructure Development
Authors: Tynan Belinda
Published: January 2007

This article provides an account of how one manager considered the alignment of an organisational vision with an implementation strategy for creating an effective organisational infrastructure. The discussion reported in the article provides a manager's view, a case, of how one institution introduced online learning initiatives. Critical to this case is the development of suitable and sustainable organisational processes that were in alignment with the organisational vision. This discussion could aid managers of virtual learning environments in higher education institutions by (a) modelling an approach to linking institutional vision and Laurillard's Conversational Framework as an implementation strategy for e-learning and, (b) improving managers' understanding of the processes of and necessity of strategic alignment.
A Smooth Passage toward an Online PhD
Authors: Cleeton Lorraine , Cleeton Gilbert
Published: January 2007

There is a need for research into understanding students' learning barriers and cognitive style of learning before they embark on an online PhD program. Online university students in the School of Education express success and difficulties electronically as they navigate through a spectrum of courses, Learning Agreements, Knowledge Area Modules (KAMs) and a dissertation. To better understand how the online student learns, Cleeton's ‘Research Barrier Questionnaire’ and Riding's ‘Cognitive Styles Analysis’ were administered to online students in their first online course at an online university. Results obtained might by useful in the construction of a curriculum model to integrate faculty–student perception and reality of best practices in teaching an ‘Introductory Course’ at an online university from the perspective of the online student. This model would be descriptive, diagnostic and prescriptive. Advice in terms of online support may then be given to students and faculty, to smooth the passage of online learning and increase its penetration rates.
A new species of Oxyascaris (Nematoda, Cosmocercidae) in the Costa Rica brook frog, Duellmanohyla uranochroa (Anura, Hylidae)
Authors: Bursey Charles , Goldberg Stephen
Published: January 2007

Oxyascaris mcdiarmidi sp. nov. (Nematoda, Cosmocercidae) from the small intestine of Duellmanohyla uranochroa from Costa Rica is described. Oxyascaris mcdiarmidi sp. nov. represents the 4th species assigned to the genus and is distinguished from congeners by the distribution pattern of the caudal papillae of the male, spicule length and vulvar position.
Enantioselective Sulfoxidation and Kinetic Resolution Combined Protocol Mediated by a Functionalized (S)‐Norcamphor‐Based Hydroperoxide/Titanium(IV) Isopropoxide System
Authors: Lattanzi Alessandra , Piccirillo Sandro , Scettri Arrigo
Published: January 2007

A functionalized tertiary furyl hydroperoxide derived from (S)‐norcamphor has been easily synthesized in good yield and in a highly diastereoselective manner. Good to high enantioselectivities (up to 99 % ee) and acceptable to good yields (up to 86 %) were achieved for the sulfoxides, by tandem stereoconvergent asymmetric sulfoxidation and kinetic resolution when using the novel hydroperoxide as oxygen donor and chirality source in the presence of catalytic loadings of titanium(IV) isopropoxide as the catalyst.
Design of a Conformationally Rigid Hydrazide Organic Catalyst
Authors: Lemay Mathieu , Aumand Livia , Ogilvie William W.
Published: January 2007

Conformational control was utilized to design a hydrazide organocatalyst for asymmetric Diels–Alder reactions, thus introducing a new aspect to organocatalysis. Diastereoselectivities and enantioselectivities of up to 96 % were achieved by the application of the rigidified catalyst. The first crystal structure of a key iminium intermediate in an organocatalyzed process is also provided.
Suzuki–Miyaura Reactions of Aryl Chloride Derivatives with Arylboronic Acids using Mesoporous Silica‐Supported Aryldicyclohexylphosphine
Authors: Sayah Reine , Glegoła Katarzyna , Framery Eric , Dufaud Véronique
Published: January 2007

The Suzuki–Miyaura reactions using mesoporous‐supported aryldicyclohexylphosphine as ligand have been investigated. The catalysts were based on SBA‐15 type mesoporous silica which was transformed in a four‐step synthesis leading to a phosphine‐containing hybrid material The most productive catalytic system studied was generated in situ from this material and the homogeneous palladium complex, Pd(OAc)2. Other catalytic systems were studied for comparison [homogeneous cataysts, a “preformed” catalyst obtained by reaction of PdCl2(PhCN)2 and the phosphine‐containing material]. Variations involving the solvent system, the substrate aryl chloride and the arylboronic acid reactant were also studied. For both in situ and preformed catalyst systems, high conversions and yields are obtained for activated aryl chlorides. Success of the reaction for unactivated aryl chlorides was limited to the catalyst formed in situ. The catalyst formed in situ was also shown to be reactive under aqueous reaction conditions in the cross‐coupling of 1‐(4‐chlorophenyl)ethanone with phenylboronic acid.
First Modular Synthesis of Dissymmetric Biaryldiphosphine Ligands Allowing Tunable Steric and Electronic Effects
Authors: Leroux Frédéric R. , Mettler Hanspeter
Published: January 2007

The first modular synthesis of a family of C1‐symmetric diphosphine ligands is presented. Their synthesis is based on unprecedented highly regioselective halogen/metal interconversions on a common polybrominated biaryl precursor. This methodology allows the functionalization of the ortho‐ and ortho′‐positions of the biaryl core. Diphosphine ligands carrying only one substituent at the 6‐position and the two phosphine substituents at the 2‐ and 2′‐position become easily accessible. The two phosphine substituents may be identical (as in compounds 2 and 3) or different (as in compounds 1 and 4). All diphosphines were prepared on gram scale, and the enantiopure ligands were obtained by chromatography of the racemate on a chiral HPLC column. The asymmetric hydrogenation of β‐keto esters, acetamidocinnamates and dimethyl itaconate revealed good to excellent asymmetric inductions of up to 99 % ee, and are often close to those of the well‐known C2‐symmetric MeO‐BIPHEP.
Improved Stabilization of Genetically Modified Penicillin G Acylase in the Presence of Organic Cosolvents by Co‐ Immobilization of the Enzyme with Polyethyleneimine
Authors: Montes Tamara , Grazú Valeria , Manso Isabel , Galán Beatriz , López‐Gallego Fernando , González Ramón , Hermoso Juan A. , García José L. , Guisán José M. , Fernández‐Lafuente Roberto
Published: January 2007

Penicillin G acylase (PGA) is an enzyme that hardly interacts with polycationic polymers (e.g., polyethyleneimine, PEI) and thus the enzyme cannot be stabilized against the action of organic solvents by its co‐immobilization with the polymer in the same support, neither covalently attached to the support nor adsorbed on the already immobilized enzyme. However, a new mutant PGA bearing eight additional Glu residues homogenously distributed throughout the enzyme surface may interact with the polymer. The co‐immobilization of the enzyme and PEI on glyoxyl‐agarose allows one to fully take advantage of the stabilization produced by the multipoint covalent attachment and by the protective hydrophilic micro‐environment generated by the polycationic polymer, enabling a significant stabilization of the immobilized PGA in the presence of organic solvents.
Binaphthol‐Based Diphosphite Ligands in Asymmetric Nickel‐Catalyzed Hydrocyanation of Styrene and 1,3‐Cyclohexadiene: Influence of Steric Properties
Authors: Wilting Jos , Janssen Michèle , Müller Christian , Lutz Martin , Spek Anthony L. , Vogt Dieter
Published: January 2007

A series of chiral (R)‐binaphthol‐based diphosphite ligands with different substituents was prepared and applied in the asymmetric nickel‐catalyzed hydrocyanation of styrene and 1,3‐cyclohexadiene to investigate the influence of their steric properties. The optimum steric properties for the hydrocyanation reaction lie within a narrow window. With the optimized ligand, hydrocyanation of styrene gave full conversion (Subs/Ni=100) with 49 % ee, the TON was determined to be 600. Hydrocyanation of 1,3‐cyclohexadiene gave 50 % conversion (Subs/Ni=500) with an excellent ee of 86 %. This demonstrates that high ees are not only accessible for vinylarenes but also for conjugated dienes in the asymmetric nickel‐catalyzed hydrocyanation.
Lewis Acid–Lewis Base‐Catalysed Enantioselective Addition of α‐Ketonitriles to Aldehydes
Authors: Lundgren Stina , Wingstrand Erica , Moberg Christina
Published: January 2007

Additions of structurally diverse α‐ketonitriles to aromatic and aliphatic prochiral aldehydes yielding highly enantioenriched acylated cyanohydrins were achieved using a combination of a titanium salen dimer and an achiral or chiral Lewis base. In most cases high yields and high enantioselectivities were observed. The ee was moderate in the initial part of the reaction but increased over time. This could be avoided, and higher ees obtained, by keeping the titanium complex, in the presence or absence of aldehyde and ketonitrile, at −40 °C prior to the addition of the Lewis base. A mechanism initiated by nucleophilic attack of the tertiary amine at the carbonyl carbon atom of the ketonitile is supported by 13C labelling experiments.
Purtscher‐like retinopathy as an initial presentation of a thrombotic microangiopathy associated with antineoplastic therapy
Authors: Parc C.
Published: January 2007

We describe the case of a 31‐year‐old female with Hodgkin's lymphoma who developed renal and retinal thrombotic microangiopathy (TM) months after autologous bone marrow transplantation. Presenting symptoms were ocular and examination findings were consistent with a Purtscher‐like retinopathy. This case demonstrates that patients being treated with antineoplastic therapy who develop TM should have an ocular examination for Purtscher retinopathy. The visual prognosis of Purtscher retinopathy is guarded. Am. J. Hematol., 2007. © 2007 Wiley‐Liss, Inc.
Biclonal low grade B‐cell lymphoma confirmed by both flow cytometry and karyotypic analysis, in spite of a normal kappa/lambda Ig light chain ratio
Authors: Delville J.P. , Heimann P. , Housni H. El , Boutriaux M. , Jeronnez A. , Remmelink M. , Lasudry J. , Pradier O. , Kentos A.
Published: January 2007

Composite low grade lymphoma with two subpopulations in a same site is uncommon. We herewith report the case of an 80‐year‐old woman who presented with isolated bilateral dacryoadenomegaly. Pathological examination of an incisional biopsy of her right lacrimal gland was consistent with a marginal zone lymphoma. Flow cytometry immunophenotyping showed two distinct clonal B‐cell populations expressing sIg D lambda or sIg M kappa restriction in the lacrimal gland, blood, and bone marrow. Both B‐cells populations were sorted from peripheral blood for molecular biology investigations and comparison with molecular data performed on tumor and bone marrow cells. IgH PCR performed on purified blood populations disclosed two monoclonal peaks: 98 bp‐sized peak in the sIg M kappa and a 107 bp in the sIg D lambda clones, respectively. The lacrimal gland tumor expressed mainly sIg M kappa population, and showed a major 98 bp‐sized peak coexisting with a very minor 107 bp peak. Cytogenetic studies showed a 46, XX,del (7) (q22q32) karyotype. Bone marrow examination at diagnosis revealed the same B‐cell clones distribution than the one observed in blood with a dominant sIg D lambda population, a Genescan profile showing a major peak of 107 bp and a minor peak of 98 bp. Chromosomal analysis disclosed a 46,XX,del (10) (?p14) karyotype without detectable 7q deletion. To our knowledge, this observation represents the first reported case of biclonal low grade lymphoma hidden behind a normal classical kappa/lambda Ig light chain ratio in blood, but clearly demonstrated by the combination of three ancillary techniques (flow cytometry both analytical and cell sorting, molecular biology, and cytogenetics) and analysis of different tissues (i.e., in this case, lacrimal gland biopsy, blood, and bone marrow. Am. J. Hematol., 2007. © 2007 Wiley‐Liss, Inc.
Mixed chimerism and graft failure following conditioning with the fludarabine and cyclophosphamide nonablative regimen; Conversion to full donor chimerism
Authors: Jillella Anand P. , Shafer Danielle , Klumpp Thomas R. , Emmons Robert V.B. , Mangan Kenneth F.
Published: January 2007

Twenty‐one patients with hematologic malignancies were treated with the fludarabine (120–125 mg/m2) and cyclophosphamide (120 mg/kg) nonmyeloablative conditioning regimen. Graft versus host disease (GVHD) and graft rejection prophylaxis was with tacrolimus and mycophenolate mofetil. Thirteen of the 21 patients (62%) had mixed chimerism (≤≤90% donor cells) at day 60 and 11 (52%) of these patients had mixed chimerism which persisted until day 100. Immunosuppression was discontinued in 12 of 13 patients and two of them converted to full chimerism by day 100. Eight patients received a donor lymphocyte infusion (DLI) and five of them converted to full donor chimerism with DLI alone. Two patients were given GM‐CSF in addition to a DLI with conversion to full donor chimerism. Three patients (14%) had graft failure requiring a second transplant using fludarabine (125 mg/m2) and melphalan (140 mg/m2). With a median followup of 2.8 years, 15 patients are alive—one with disease and 14 with no disease. Two patients died of acute GVHD, one of chronic GVHD, and three due to progressive disease. We conclude that the nonmyeloablative fludarabine/cyclophosphamide regimen results in a significant incidence of mixed chimerism and graft rejection but is well tolerated. We suggest a more intense regimen, such as fludarabine and melphalan, be used in patients with a high risk of early disease progression to establish early engraftment and graft versus tumor effect. Am. J. Hematol., 2007. © 2007 Wiley‐Liss, Inc.
In vitro reactivity of factor VIII inhibitors with von Willebrand factor in different commercial factor VIII concentrates
Authors: Tagariello Giuseppe , Zanotto Daniela , Radossi Paolo , Sartori Roberto , Belvini Donata , Salviato Roberta
Published: January 2007

A relevant aspect in the treatment of patients with hemophilia A (HA) presenting inhibitor against factor VIII (FVIII) is the different antigenicity of FVIII used for replacement therapy. The aim of the study was to assess the effect of different products, with variable von Willebrand factor (vWF) concentration, in preventing the binding of inhibitor to FVIII. The reactivity of inhibitors from plasma of 18 patients with HA versus three commercial concentrates containing different amounts of vWF was compared. The results show that increasing amounts of vWF might have a protective effect on the transfused FVIII inactivation. Am. J. Hematol., 2007. © 2007 Wiley‐Liss, Inc.
Frequency of intron 1 and 22 inversions of factor VIII gene in Mexican patients with severe hemophilia A
Authors: Mantilla‐Capacho Johanna Milena , Beltrán‐Miranda Claudia Patricia , Luna‐Záizar Hilda , Aguilar‐López Lilia , Esparza‐Flores María Amparo , López‐Guido Beatriz , Troyo‐Sanromán Rogelio , Jaloma‐Cruz Ana Rebeca
Published: January 2007

Hemophilia A (HA) is one of the most common inherited bleeding disorders caused by FVIII gene mutations. Inversion of intron 22 (inv22) originates 50% of cases of severe HA and is a major risk factor for inhibitor development. Inversion of intron 1 (inv1) has been reported to occur in 2–3% of severe HA patients. We studied both inversions to determine their frequencies in Mexican patients with severe HA and to compare these data with other HA populations. The inv22 was evaluated as a risk factor for FVIII inhibitor development in severe HA patients. We studied 44 patients from 31 severe HA families for the detection of inv22 and 94 patients from 65 families to detect inv1. We used the subcycling long‐distance PCR to detect inv22 and rapid PCR in duplex reactions to detect inv1. We found a frequency of 45% for the inv22 and no inv1‐positive patients (0%). These frequencies were not statistically different from other populations, although haplotype analyses of FVIII gene and telomeric regions should be incorporated to explore population‐specific variation of inv1 frequencies. Inv22‐positive patients showed 1.88X higher risk for developing inhibitors with respect to patients carrying other severe mutations; however, this OR value was not significant. Our findings confirm inv22 as a hot‐spot for severe HA and evidence the low frequency of inv1 in a Mexican population. The non‐significant risk for developing inhibitors among inv22‐positive patients agrees with the variety of genetic and non‐genetic factors involved in such a complication. Am. J. Hematol., 2007. © 2007 Wiley‐Liss, Inc.
Evidence for linkage of red blood cell size and count: Genome‐wide scans in the Framingham Heart Study
Authors: Lin Jing‐Ping , O'Donnell Christopher J. , Jin Li , Fox Caroline , Yang Qiong , Cupples L. Adrienne
Published: January 2007

Red blood cell (RBC) count and size are major criteria for evaluating anemia and related hematology disease diagnoses. While environmental factors influence RBC count (RBCC) and size, mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH), studies have indicated that each of these measures has a substantial genetic component. So far, no linkage analysis or genome scan has been reported. We carried out 10 cM genome‐wide scans on RBCC, MCV, and MCH in a community‐based Caucasian cohort, the Framingham Heart Study, using 325 pedigrees with 1,144 individuals genotyped and phenotyped. Using variance‐component linkage methods, heritabilities were estimated as 56, 52, and 52% after covariate adjusted for RBCC, MCV, and MCH, respectively. For RBCC, we found a maximum LOD score of 3.2 on chromosome 19, 24 cM (7.0 Mbp). Near this region, there lie a few important candidate genes, including erythropoietin receptor and erythroid Krüppel‐like factor. For linkage analyses for MCV and MCH, there were coinciding maximized LOD scores on chromosome 11, 9 cM (5.2 Mbp) with values of 3.8 and 3.6, respectively. Under the peak resides the hemoglobin β cluster ‐ several β‐like genes, which are important candidates for RBC size. In subsequent analyses, we excluded individuals with low MCV to assess the possible influence of β‐thalassemia carriers, and there continued to be evidence for linkage in the same region on chromosome 11p15 (LOD scores of 2.6 and 2.7 for MCV and MCH, respectively). For MCV, we also identified a new region on chromosome 6q24 with a LOD score of 2.9. These findings suggest that further studies are warranted to identify potential causal genetic variants for RBC size and count and related erythrocyte indices. Am. J. Hematol., 2007. Published 2007 Wiley‐Liss, Inc.