bluuebunny/crossref_metadata_2025_split huggingface dataset:
Confined Microplot Size for Nitrogen‐15 Uptake by Corn Plants in a Corn Intercrop System
Authors: Zhou Xiaomin , Leibovitch Stewart , MacKenzie Angus F. , Madramootoo Chandra A. , Dutilleul Pierre , Smith Donald L. 
Published: July 2010

AbstractThe high cost of labeled N fertilizer places practical limitations on measuring the fate of applied N. Applying of the labeled 15N to a microplot within a larger plot can reduce the cost. The objective of this study was to assess microplot dimensions required to produce reliable 15N data and cropping system effects on corn 15N uptake under a regime of monocropped corn (Zea mays L.) and corn intercropped with annual Italian ryegrass (Lolium multiflorum Lam.). Nitrogen was applied to large plots (15 by 75 m) at 270 kg N ha−1 on a fine, silty, mixed, nonacid, frigid Typic Humaquept soil during the 1993 and 1994 growing seasons. Enriched N fertilizer was applied to 1.15 by 1‐m2 confined microplots located in opposite halves of the large plot in each year of the study. Corn plants inside the confined microplots were sampled at 0.1, 0.3, and 0.5 m from the end borders of each microplot. In 1993, monocropping resulted in increases in leaf, stalk, and total dry matter production of 22, 41, and 30%, respectively, within microplots and relative to intercropped corn. There were no cropping system effects for these parameters in 1994. Monocropping increased atom % 15N enrichment in corn grain and stalks and increased fertilizer N recovery in all plant tissue compared with intercropping in both years. There were no differences in atom % 15N enrichment and fertilizer N recovery for plants harvested at the three sampling positions. These results suggest that a confined microplot with an area as small as 0.4 by 1.15 m can provide a reliable measure of fertilizer N recovery for corn plants in monocrop or intercrop systems. Any or all of the five plants within the microplot could be used to supply a reliable estimation of 15N recovery by corn plants.
Soybean Cultivars and Insect Defoliation: Yield Loss and Economic Injury Levels
Authors: Haile Fikru J. , Higley Leon G. , Specht James E. 
Published: July 2010

AbstractUnderstanding the response of soybean [Glycine max (L.) Merr.] cultivars to insect defoliation is important for identifying differences in insect tolerance and compensation among soybean genotypes, for assessing yield loss differences among cultivars, and for determining if a single economic injury level (EIL) can be used for all cultivars. Therefore, this study was conducted to evaluate the relative tolerance of selected soybean cultivars to insect defoliation. Field experiments were conducted in 1994 and 1995 on three indeterminate soybean cultivars: Dunbar, Corsica, and Clark. Sequential defoliation (46‐66%) was imposed manually at the R2 stage (reproductive development of soybean at full flowering), guided by an insect consumption model. Leaf area index, percent light interception, growth, and yield data were determined. Because of ample rainfall during the soybean growing period in 1994, defoliation did not affect soybean yield; all cultivars compensated for all levels of defoliation via delayed leaf senescence and compensatory regrowth, which enhanced the light interception capacity of defoliated soybean canopies. In 1995, however, defoliation caused a significant yield reduction (15‐70%) in all cultivars; this yield reduction was greater for Dunbar than the other two cultivars. In both years, yields were directly related to the light interception capacity of soybean canopies after defoliation. There were significant EIL differences among soybean cultivars. Large differences in EILs among cultivars suggest a need to revise existing EILs for defoliating pest species.
Fertilizer and Soil Nitrogen Use by Corn and Border Crops in a Strip Intercropping System
Authors: Ghaffarzadeh Mohammadreza , Préchac Fernando García , Cruse Richard M. , Harbur Matthew M. 
Published: July 2010

AbstractCorn (Zea mays L.) has greater yield potential when strip‐intercropped than when monocropped, but this potential may be compromised by a failure to understand how N requirements change with row position and the possible N competition of adjacent crops. A four block, completely randomized, split‐plot experiment was conducted on a Haig loam soil (fine, smectitic, mesic Vertic Argiaquolls) in southern Iowa, to determine crop utilization of N fertilizer pointinjected into corn rows. Nitrogen fertilizer uptake was evaluated in (i) corn rows injected with labeled N fertilizer; (ii) corn rows adjacent to the injected rows; and (iii) plants at the edge of the adjacent soybean [Glycine max (L.) Merr.] and oat (Avena sativa L.)‐alfalfa (Medicago saliva L.) strips. Main treatments consisted of three tillage systems: conventional tillage (CT), reduced tillage (RT), and no‐till (NT). Subplot treatments consisted of point injection of l5N‐enriched NH4NO3 (67 kg N ha−1) in‐row at three row positions within the corn strips. Grain and stover yield, Kjeldahl N, and isotope composition of plant materials were determined. Corn yield and labeled‐N recovery differed with tillage to the extent that tillage affected early and total season moisture availability. Labeled‐N recovery in labeled rows did not differ with row position. Labeled‐N recovery in unlabeled rows or crop borders was typically less than 5% of that recovered by labeled rows. Nitrogen is primarily recovered by the row to which it is applied; therefore, row‐by‐row precision applications seem to be an appropriate management tool.
Agricultural Advisory Committees: How They Rate Their Effectiveness in Guiding Research
Authors: Sweeney Daniel W. , Pontius Jeffrey S. 
Published: July 2010

AbstractUniversity faculty located and conducting research at off‐campus agricultural research centers often are advised by committees representing agribusiness, producers, and extension personnel. A two‐page questionnaire was sent in 1996 to the directors, faculty, and members of the advisory committees of three research centers each in Arkansas, Florida, Minnesota, Nebraska, and Texas and two research centers in Kansas to assess opinions about the composition, structure, goals, and effectiveness of agricultural advisory committees. All occupational groups surveyed felt that advisory committees can provide valuable input for agricultural research, but were less convinced that they accomplish their goals. In general, research center directors, extension personnel, and research faculty tended to be more reserved than agribusiness and producer respondents in their opinions on the performance of advisory committees. Respondents believed that agricultural research advisory committees should comprise representatives of agribusiness, area producers, extension personnel, and research faculty who are chosen by those groups, although research center directors did not support extension personnel or research faculty having a voice in the selection process. Committee members should serve a term of 3 to 4 years. Goals should be more defined and should help to identify needs and guide research by providing direction and focus, being an advocate for the research center, and providing input on fund raising and management. Improved communication, more meetings with definite agendas, and better attendance were identified to help improve the success of advisory committees. Overall, the potential for benefit is high, but agricultural advisory committees often are perceived as needing to improve their effectiveness.
Inositol Hexaphosphate: I. Quantitative Determination in Extracts of Soils and Manures
Authors: Caldwell A. G. , Black C. A. 
Published: July 2010

AbstractA procedure was developed for the quantitative determination of inositol hexaphosphates in extracts of soils and manures. The inositol hexaphosphates were separated from other phosphorus compounds by anion‐exchange chromatography in a simplified adaptation of the technique developed originally by Smith and Clark. Dilute hydrochloric acid extracts of manures can be added directly to the exchange columns, but extracts of soils obtained by the usual acid‐alkali extraction procedure must be given a preliminary treatment to remove organic matter that otherwise would flocculate under the acid conditions in the exchange columns.
Applied and Residual Nitrate‐Nitrogen Effects on Irrigated Grain Sorghum Yield
Authors: Onken Arthur B. , Sunderman Herbert D. 
Published: July 2010

AbstractMultirate nitrogen studies were conducted for a 3‐year period, on an irrigated clay loam soil at two locations, to determine the influence of applied and residual soil N on the yield of grain sorghum (Sorghum bicolor L. Moench). Soil samples were taken prior to fertilizer application in depth increments of 0–15, 15–30, 30–61, and 61–91 cm and analyzed for nitrate. Applied and residual soil NO3‐‐N were found to influence grain yields. Regression analysis of the data showed highly significant relationships between (i) quantities of soil nitrates measured at upper depths to those measured at lower depths, and (ii) grain yield and applied N + residual NO3‐‐N. Best correlations were obtained when residual NO3‐‐N was included in the regression equation. Results indicated that soil samples taken to 15 or 30 cm would be sufficient for evaluation of residual nitrogen effects.
Relationships Between Saturated Hydraulic Conductivity and Morphometric Data of an Argillic Horizon
Authors: Anderson J. L. , Bouma J. 
Published: July 2010

AbstractA method of calculating Ksat in pedal soil materials on the basis of morphometric data yielded reproducible results for seven soil peels sampled in the argillic horizon of a Batavia silt loam. Calculated values were reasonably close to those measured in situ with the double tube method. The method was also successfully applied to impregnated horizontal sections through soil cores. Dye studies demonstrated the validity of some of the underlying assumptions of the method, which predicts a strong relationship between core height and measured hydraulic conductivity in pedal soil materials. Experiments confirmed this relationship and a representative core size was defined for the studied horizon using the morphometric data.
Acidity and Aluminum Restraints on Nodulation, Nitrogen Fixation, and Growth of Phaseolus vulgaris in Solution Culture
Authors: Franco A. A. , Munns D. N. 
Published: July 2010

AbstractThe effects of acidity and aluminum (Al) on nodulation, nitrogen (N) fixation, and bean shoot and root growth were studied in solution and sand culture in greenhouse experiments to help explain the frequent failure of N2‐dependent bean in acid soils. Aluminum concentrations were maintained in solution by keeping low levels of phosphorus (P) at pH 4.5.Concentrations of Al up to 83 µM did not affect root dry weight, nodule growth, and nitrogenase activity of either bean cultivar tested. Low levels of Al (19 µM) increased taproot elongation but decreased total root length; at higher Al concentrations, the taproot also became stunted. Increasing CaCl2 from 0.2 to 2 mM in solution suppressed Al toxicity. Shoot growth was significantly decreased by 19 µM Al in P. vulgaris cv. Carioca but not in cv. Venezuela 350. Root colonization and/or infection by Rhizobium was reduced by Al concentrations >33 µM but was less sensitive than total root elongation or shoot growth.Solution culture pH in the range 4.5 to 5.5 did not affect nodule growth and nitrogenase activity, but a decrease in pH from 5.5 to 5.0 decreased number of nodules formed per plant from 60 to 10, indicating that pH can be a major limiting factor of early nodulation with the cultivars and Rhizobium strains tested.
Evolution of Dinitrogen and Nitrous Oxide from Nitrogen‐15 Fertilized Soil Cores Subjected to Wetting and Drying Cycles
Authors: Mulvaney R. L. , Kurtz L. T. 
Published: July 2010

AbstractA laboratory study was conducted to establish trends in evolution of dinitrogen (N2) and nitrous oxide (N2O) associated with the wetting and drying of soils and to assess the relative significance of nitrification and denitrification as sources of the N2O evolved from NH+4‐fertilized soils. Mass spectrometric procedures were used to analyze atmospheric samples collected each day during a 6‐week period from intact soil cores treated with 15N‐labeled KNO3 (65.5 atom % 15N) or (NH4)2SO4 (81.4 atom % 15N) at a rate equivalent to 100 kg N ha−1 and periodically treated with water to simulate rainfall. Data reported show that N2 and N2O were evolved only if enough water was applied to increase the soil moisture content to a level above the 0.03‐MPa moisture percentage, that these gases were evolved concurrently, that maximal evolution occurred 2 to 9 d after the water had been applied, and that more N2 was usually evolved than N2O. Calculations to determine the origin of the N2 and N2O evolved from the soil cores showed that most (usually 60–80%) of this N2 and N2O was derived from the fertilizer applied, that the percentage of fertilizer‐derived N2 and N2O was greater for the NO‐3‐treated cores than for the NH+4‐treated cores, and that the 15N enrichment of the N2O often exceeded that of the N2. The work reported provides support for the usual assumption that N2 and N2O evolved from NH+4‐, as well as NO‐3, fertilized soils originate largely, if not entirely, through denitrification of NO‐3 under anaerobic conditions, and it suggests that evolution of these gases follows an over‐all cycle associated with wetting and drying of the soil. Very little, if any, N2 and N2O appears to be evolved when the soil moisture content is well below field capacity. Evolution virtually ceases when the soil is saturated by rainfall, and it subsequently increases as the soil dries, with maximal evolution occurring several days after the rainfall. Evolution then decreases and eventually ceases.
Single Waterdrop Splash Detachment and Mechanical Properties of Soils
Authors: Nearing M. A. , Bradford J. M. 
Published: July 2010

AbstractThis study was an assessment of the use of soil mechanical properties to predict soil detachment by single waterdrop impact. Soil mechanical properties were measured on four soils with a triaxial consolidated‐undrained compression test and a Swedish fall‐cone device. The weight of soil detached was measured for 5.7‐mm diameter drops falling a distance of 13 m. The results indicated that strength and pre‐failure deformational properties, as measured by the triaxial test alone, were not good predictors of soil resistance to splash. As previously reported, soil splash weight was a linear function of the ratio of waterdrop kinetic energy to fall‐cone strength on a per soil basis, but the slope of the line differed among soils. The slopes were, however, greater for soils with greater consolidated, undrained friction angles as determined in the triaxial test and expressed in terms of total stresses. Therefore, the fall‐cone strength term was reduced as a function of the triaxial friction angle, and detachment was plotted versus the ratio of raindrop kinetic energy to the corrected fall‐cone strength term. The resultant relationship was linear with the same slope for all four soils. This result was explained in terms of our current understanding of the soil splash mechanism. The fall‐cone alone predicts the initial splash phase of cavity formation upon impact, but overpredicts the resistance of the soil to subsequent lateral jetting of water.
John White A.M., M.D., F.LS. (c. 1756–1832), Surgeon-General of New South Wales: a new biography of the messenger of the echidna and waratah
Authors: NELSON E. CHARLES 
Published: July 2010

John White, Surgeon-General of New South Wales, is best remembered for his handsome book Journal of a voyage to new South Wales published in London during 1790. He was a native of County Fermanagh in northwestern Ireland. He became a naval surgeon and in this capacity was appointed to serve as surgeon on the First Fleet which left England for New South Wales (Australia) in 1787. While living in New South Wales, White adopted Nanberree, an aboriginal boy, and fathered a son by Rachel Turner, a convict, who later married Thomas Moore. John White returned to England in 1795, became a Fellow of the Linnean Society of London and was granted the degrees of Doctor of Medicine and Master of Arts by the University of St Andrews. White was married twice, and was survived by his second wife and his four children, including his illegitimate, Australian-born son, Captain Andrew Douglas White. Dr John White died in 1832 aged 75 and is buried in Worthing, Sussex, England. While serving as Surgeon-General at Sydney Cove, New South Wales, between 1788 and 1794 John White collected natural history specimens and assembled a series of paintings of plants and animals. After returning to England, White lent these paintings to botanists and zoologists, and permitted copies to be made. Thus, he contributed substantially to European knowledge of the indigenous flora and fauna of Australia.
Some More Observations on the Unique Electrochemical Properties of Electrode–Monolayer–Nanoparticle Constructs
Authors: Dyne Jonathan , Lin Yu‐Shan , Lai Leo M. H. , Ginges Joshua Z. , Luais Erwann , Peterson Joshua R. , Goon Ian Y. , Amal Rose , Gooding J. Justin 
Published: July 2010

AbstractPhysical and electrochemical properties of gold nanoparticle‐based electrodes are highlighted. Polycrystalline gold electrodes are passivated by a self‐assembled monolayer, then the immobilization of gold nanoparticles “switch on” the electrochemical reactivity of ruthenium. Herein, gap‐mode Raman studies show that the location of the nanoparticles is on the top of the monolayer, meaning that the “switching on” cannot be attributed to a direct electrical contact between nanoparticles and the gold support. This “switching on” feature is also not affected by the size of the gold nanoparticles with a range of diameters between 4 and 67 nm. Further, the charge of the nanoparticles is investigated by grafting chemical groups onto the nanoparticles which is observed to alter the electron‐transfer kinetics. The variation in rate constant however is insufficient to attribute the “switching on” phenomenon to a possible adsorption of the redox species onto the nanoparticles.
Structure of an atypical Tudor domain in the Drosophila Polycomblike protein
Authors: Friberg Anders , Oddone Anna , Klymenko Tetyana , Müller Jürg , Sattler Michael 
Published: July 2010

AbstractPost‐translational modifications of histone tails are among the most prominent epigenetic marks and play a critical role in transcriptional control at the level of chromatin. The Polycomblike (Pcl) protein is part of a histone methyltransferase complex (Pcl‐PRC2) responsible for high levels of histone H3 K27 trimethylation. Studies in Drosophila larvae suggest that Pcl is required for anchoring Pcl‐PRC2 at target genes, but how this is achieved is unknown. Pcl comprises a Tudor domain and two PHD fingers. These domains are known to recognize methylated lysine or arginine residues and could contribute to targeting of Pcl‐PRC2. Here, we report an NMR structure of the Tudor domain from Drosophila Pcl (Pcl‐Tudor) and binding studies with putative ligands. Pcl‐Tudor contains an atypical, incomplete aromatic cage that does not interact with known Tudor domain ligands, such as methylated lysines or arginines. Interestingly, human Pcl orthologs exhibit a complete aromatic cage, suggesting that they may recognize methylated lysines. Structural comparison with other Tudor domains suggests that Pcl‐Tudor may engage in intra‐ or intermolecular interactions through an exposed hydrophobic surface patch.
Regulatory Function of Histone Modifications in Controlling Rice Gene Expression and Plant Growth
Authors: Zhou Dao-Xiu , Hu Yongfeng 
Published: July 2010

Abstract
Histone modifications play pivotal roles in chromatin remodeling and gene regulation. Rice genome possesses multiple genes encoding different classes of histone modification enzymes. Specific histone modification patterns in rice are associated with either heterochromatic or euchromatic regions or related to gene expression. Functional studies of several rice genes encoding histone deacetylases and histone methyltransferases and demethylases reveal specific regulators involved in transposon repression, development regulation, and responses to environmental conditions. Functional interplay between rice histone modification regulators in gene regulation and transposon silencing and their implication in rice epigenetic variation are discussed.
Intra‐industry Adjustment to Import Competition: Theory and Application to the German Clothing Industry
Authors: Raff Horst , Wagner Joachim 
Published: July 2010

AbstractThis paper uses an oligopoly model with heterogeneous firms to examine how an industry adjusts to rising import competition. The model predicts that in the short run the least efficient firms in the industry become inactive, surviving firms face a fall in output, mark‐ups and profits, and average industry productivity increases due to a selection effect. These pro‐competitive effects of import penetration on the domestic industry disappear in the long run. The predictions for the short run are confirmed in an empirical study of the German clothing industry.
Deficient recognition of emotional prosody in primary focal dystonia
Authors: Nikolova Z. T. , Fellbrich A. , Born J. , Dengler R. , Schröder C. 
Published: July 2010

Background:  Primary dystonia is a movement disorder attributed mainly to basal ganglia dysfunction. Besides motor control, striatopallidal structures are known to implement also non‐motor functions including processing of cognitive and emotional information. Previous research has already demonstrated deficient recognition of emotional faces in patients with primary focal dystonia. However, it remains elusive if emotional prosody processing in dystonia is also affected.Methods:  In this study, 30 patients with primary cervical dystonia (CD) and 30 healthy control subjects (HC) had to classify auditory presented words according to their emotional prosody (angry, happy, relaxed, sad).Results:  Analysis of hit rates and reaction times revealed a significantly poorer performance of patients with CD in judging angrily intonated words. Additional psychological assessment (SCL‐90 R) demonstrated a higher level of psychological distress in patients with CD who displayed symptoms of somatization, anxiety and depression.Conclusions:  Together these findings bring further insight into the basal ganglia involvement in processing of emotional prosody and emphasize the importance to identify the psychopathological symptoms in patients with CD as complementary to the motor deficit.