bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative Description of the Germination of Littleseed Canarygrass (Phalaris minor) in Response to Temperature
Authors: Derakhshan Abolfazl , Gherekhloo Javid , Vidal Ribas A. , De Prado Rafael
Published: April 2014

Littleseed canarygrass is a troublesome grass weed in wheat fields in Iran. Predicting weed emergence dynamics can help farmers more effectively control weeds. In this work, four nonlinear regression models (beta, three-piece segmented, two-piece segmented, and modified Malo's exponential sine) were compared to describe the cardinal temperatures for the germination of littleseed canarygrass. Two replicated experiments were performed with the same temperatures. An iterative optimization method was used to calibrate the models and different statistical indices (mean absolute error [MAE], coefficient of determination [R2], intercept and slope of the regression equation of predicted vs. observed hours to germination) were applied to compare their performance. The three-piece segmented model was the best model to predict the germination rate (R2= 0.99, MAE = 0.20 d, and coefficient of variation 1.01 to 4.06%). Based on the model outputs, the base, the lower optimum, the upper optimum, and the maximum temperatures for the germination of littleseed canarygrass were estimated to be 4.69, 22.60, 29.62, and 38.13 C, respectively. The thermal time required to reach 10, 50, and 90% germination was 31.98, 39.26 and 45.55 degree-days, respectively. The cardinal temperatures depended on the model used for their estimation. Overall, the three-piece segmented model was better suited than the other models to estimate the cardinal temperatures for the germination of littleseed canarygrass.
The Future of Herbicides and Genetic Technology: Ramifications for Environmental Stewardship
Authors: Senseman Scott A. , Grey Timothy L.
Published: April 2014

Environmental stewardship refers to responsible use and protection of the natural environment through conservation and sustainable practices. Aldo Leopold (1887 to 1948) championed environmental stewardship based on a land ethic “dealing with man's relation to land and to the animals and plants that grow upon it.” Environmental stewardship as it relates to weed science has taken on varying roles as chemical weed control took hold in managing crops as a general practice soon after World War II, and became a well-known issue during the Vietnam War, with the extensive use of Agent Orange. As technologies in both chemistry and genetics have evolved, chemical weed control became safer with the advent of less toxicologically damaging materials. Combining toxicologically safe herbicides with genetic manipulation made it possible to apply chemicals that previously would have caused plant death, seemingly providing a magic bullet that simplified weed control for many producers during the mid to late 1990s. University scientists were guarded during the introduction of this technology; many understood that the magic bullet had flaws. By using predominately POST applications on weed species, genetic selection has given rise to substantial resistance, therefore presenting weed scientists with a grand challenge for the future. As new genetic technology is introduced for existing and future weed management problems, how will environmental stewardship be addressed and how can this technology be preserved? How can a producer afford it and how can they afford not to use it? When we have weeds present that used to be managed by herbicides and genetic technology, then society will be forced to deal with the same social, economic, agronomic, and environmental issues they dealt with prior to such technology. Herbicide-resistance technology and the concomitant herbicide-resistant weeds have provided a perfect case study to learn from if those in academia, extension, and industry will pay attention. Continuing education of the producer will be perhaps the biggest key in meeting the challenge to produce a safe and plentiful food supply for a growing population with minimal adverse effects of weeds while providing a desirable degree of environmental stewardship.
Organic Farmer Knowledge and Perceptions are Associated with On-Farm Weed Seedbank Densities in Northern New England
Authors: Jabbour Randa , Gallandt Eric R. , Zwickle Sarah , Wilson Robyn S. , Doohan Doug
Published: April 2014

Weed management remains a high priority for organic farmers, whose fields generally have higher weed density and species diversity than those of their conventional counterparts. We explored whether variability in farmer knowledge and perceptions of weeds and weed management practices were predictive of variability in on-farm weed seedbanks on 23 organic farms in northern New England. We interviewed farmers and transcribed and coded interviews to quantify their emphasis on concepts regarding knowledge of ecological weed management, the perceived risks and benefits of weeds, and the perceived risks and benefits of weed management practices. To characterize on-farm weed seedbanks, we collected soil samples from five fields at each farm (115 fields total) and measured germinable weed seed density. Mean weed seed density per farm ranged from 2,775 seeds m−2to 24,678 seeds m−2to a soil depth of 10 cm. Farmers most often reported hairy galinsoga and crabgrass species (Digitariaspp.) as their most problematic weeds. The proportion of the sum of these two most problematic weeds in each farm's seedbank ranged from 1 to 73% of total weed seed density. Farmer knowledge and perceptions were predictive of total seed density, species richness, and proportion of hairy galinsoga and crabgrass species. Low seed densities were associated with farmers who most often discussed risks of weeds, benefits of critical weed-free management practices, and learning from their own experience. These farmers also exhibited greater knowledge of managing the weed seedbank and greater understanding of the importance of a long-term strategy. Targeted education focusing on this set of knowledge and beliefs could potentially lead to improved application and success of ecological weed management in the future, thus decreasing labor costs and time necessary for farmers to manage weeds.
Flucarbazone–Sodium Absorption, Translocation, and Metabolism in Bermudagrass, Kentucky Bluegrass, and Perennial Ryegrass
Authors: McCullough Patrick E. , Sidhu Sudeep S. , Singh Rashmi , Reed Thomas V.
Published: April 2014

Perennial ryegrass is overseeded in bermudagrass and Kentucky bluegrass to improve turf quality, but selective control may be warranted for transition back to monostand turfgrass. Flucarbazone–sodium controls perennial ryegrass in bermudagrass and Kentucky bluegrass, but the physiological basis of selectivity has received limited investigation. Greenhouse and laboratory experiments were conducted to evaluate efficacy, absorption, translocation, and metabolism of flucarbazone–sodium in these grasses. Flucarbazone–sodium reduced perennial ryegrass shoot mass from the nontreated an average ≈ 22 times and 3 times more than bermudagrass and Kentucky bluegrass at 4 wk after treatment, respectively. In laboratory experiments, foliar and root absorption of14C–flucarbazone–sodium were similar among species. Bermudagrass distributed ≈ 25% more foliar-absorbed14C to nontreated shoots than Kentucky bluegrass and perennial ryegrass. From root applications, all grasses averaged 84% distribution of14C to shoots. Bermudagrass and Kentucky bluegrass metabolized 100% and 74% of14C–flucarbazone–sodium at 1 d after treatment (DAT), whereas perennial ryegrass metabolism measured 44, 58, and 65% at 1, 3, and 7 DAT, respectively. Bermudagrass, Kentucky bluegrass, and perennial ryegrass had 4, 4, and 2 metabolites after 7 d, respectively. Results suggest differential metabolism of flucarbazone–sodium is attributed to selectivity for controlling perennial ryegrass in bermudagrass and Kentucky bluegrass.
Integrated Weed Management Using Planting Pattern, Cultivar, and Herbicide in Dry-Seeded Rice in Northwest India
Authors: Mahajan Gulshan , Poonia Vikas , Chauhan Bhagirath S.
Published: April 2014

Field experiments were conducted in Punjab, India, in 2011 and 2012 to study the integrated effect of planting pattern [uniform rows (20-cm spacing) and paired rows (15-, 25-, and 15-cm spacing)], cultivars (PR-115 and IET-21214), and weed control treatments (nontreated control, pendimethalin 750 g ai ha−1, bispyribac-sodium 25 g ai ha−1, and pendimethalin 750 g ha−1 followed by bispyribac-sodium 25 g ha−1) on weed suppression and rice grain yield in dry-seeded rice. In the nontreated control, IET-21214 had higher grain yield than PR-115 in both planting patterns. However, such differences were not observed within the herbicide treatment. IET-21214 in paired rows, even in nontreated control, provided grain yield (4.7 t ha−1) similar to that in uniform rows coupled with the sole application of pendimethalin (4.3 t ha−1) and bispyribac-sodium (5.0 t ha−1). In uniform rows, sequential application of pendimethalin (PRE) and bispyribac-sodium (POST) provided the highest grain yield among all the weed control treatments and this treatment produced grain yield of 5.9 and 6.1 t ha−1 for PR-115 and IET-21214, respectively. Similarly, in paired rows, PR-115 in paired rows treated with sequential application of pendimethalin and bispyribac-sodium had highest grain yield (6.1 t ha−1) among all the weed control treatments. However, IET-21214 with the sole application of bispyribac-sodium produced grain yield similar to the sequential application of pendimethalin and bispyribac-sodium. At 30 days after sowing, PR-115 in paired rows coupled with pendimethalin application accrued weed biomass (10.7 g m−2) similar to the sequential application of pendimethalin and bispyribac-sodium coupled with uniform rows (8.1 g m−2). Similarly, IET-21214 with bispyribac-sodium application provided weed control similar to the sequential application of pendimethalin and bispyribac-sodium. Our study implied that grain yield of some cultivars could be improved by exploring their competitiveness through paired-row planting patterns with less use of herbicides.
Distribution of Weedy Red Rice (Oryza sativa) Resistant to Imidazolinone Herbicides and its Relationship to Rice Cultivars and WildOryzaSpecies
Authors: Goulart Ives C. G. R. , Borba Tereza C. O. , Menezes Valmir G. , Merotto Aldo
Published: April 2014

Several weedy red rice populations have evolved resistance to imidazolinone herbicides worldwide. The understanding of the factors related to the herbicide resistance in weedy red rice is important to prevent its occurrence in new areas where imidazolinone-resistant rice cultivars are being used, and to manage the new rice cultivars resistant to herbicides with modes of action other than the acetolactate synthase (ALS)-inhibitors that are being developed. The objectives of this study were to analyze the relationship of weedy red rice populations from southern Brazil with rice cultivars and wildOryzaspecies and to evaluate the occurrence of introgression from rice cultivars and seed migration as the origin of resistance to imidazolinone herbicides in weedy rice. The study was based on 27 weedy red rice populations, seven rice cultivars, and four wildOryzaspecies that were genotyped with 24 simple sequence repeats and threeALS-specific single-nucleotide polymorphism markers. A large proportion of the genetic variation of the weedy red rice populations was found within (74%) rather than among populations (26%). The weedy red rice populations were more closely related to the newer rice cultivars that are imidazolinone-resistant than to the older cultivars. The South American nativeOryza glumaepatulaand the other wildOryzaspecies—Oryza rufipogon, Oryza longistaminata, andOryza glaberrima—clustered separately from weedy red rice populations, indicating a low likelihood of introgression among weedy red rice and these wild species. Seed migration was an important factor in the genetic structure of the evaluated weedy red rice populations, although gene flow by pollen from resistant cultivars was the principal reason for the spread of herbicide resistance.
Foliar Application of Glyphosate Affects Molecular Mechanisms in Underground Adventitious Buds of Leafy Spurge (Euphorbia esula) and Alters Their Vegetative Growth Patterns
Authors: Doğramacı Münevver , Anderson James V. , Chao Wun S. , Foley Michael E.
Published: April 2014

Long-term control of leafy spurge with glyphosate requires multiple applications because the plant reproduces vegetatively from abundant underground adventitious buds, referred to as crown and root buds. Determining the molecular mechanisms involved in controlling vegetative reproduction in leafy spurge following foliar glyphosate treatment could identify limiting factors or new targets for manipulation of plant growth and development in invasive perennial species. Thus, we treated leafy spurge plants with 0 or 2.24 kg ai ha−1glyphosate to determine its impact on selected molecular processes in crown buds derived from intact plants and plants decapitated at the soil surface 7 d after glyphosate treatment. New shoot growth from crown buds of foliar glyphosate-treated plants was significantly reduced compared with controls after growth-inducing decapitation, and had a stunted or bushy phenotype. Quantification of a selected set of transcripts involved in hormone biosynthesis and signaling pathways indicated that glyphosate had the most significant impact on abundance ofENT-COPALYL DIPHOSPHATE SYNTHETASE 1, which is involved in a committed step for gibberellin biosynthesis, and auxin transporters includingPINs, PIN-LIKES, andABC TRANSPORTERS. Foliar glyphosate treatment also reduced the abundance of transcripts involved in cell cycle processes, which would be consistent with altered growth patterns observed in this study. Overall, these results suggest that interplay among phytohormones such as auxin, ethylene, and gibberellins affect vegetative growth patterns from crown buds of leafy spurge in response to foliar glyphosate treatment.
Rhizosphere Microbial Community Dynamics in Glyphosate-Treated Susceptible and Resistant Biotypes of Giant Ragweed (Ambrosia trifida)
Authors: Schafer Jessica R. , Hallett Steven G. , Johnson William G.
Published: April 2014

In a previous study, glyphosate-susceptible and -resistant giant ragweed biotypes grown in sterile field soil survived a higher rate of glyphosate than those grown in unsterile field soil, and the roots of the susceptible biotype were colonized by a larger number of soil microorganisms than those of the resistant biotype when treated with 1.6 kg ae ha−1glyphosate. Thus, we concluded that soil-borne microbes play a role in glyphosate activity and now hypothesize that the ability of the resistant biotype to tolerate glyphosate may involve microbial interactions in the rhizosphere. The objective of this study was to evaluate differences in the rhizosphere microbial communities of glyphosate-susceptible and -resistant giant ragweed biotypes 3 d after a glyphosate treatment. Giant ragweed biotypes were grown in the greenhouse in unsterile field soil and glyphosate was applied at either 0 or 1.6 kg ha−1. Rhizosphere soil was sampled 3 d after the glyphosate treatment, and DNA was extracted, purified, and sequenced with the use of Illumina Genome Analyzer next-generation sequencing. The taxonomic distribution of the microbial community, diversity, genera abundance, and community structure within the rhizosphere of the two giant ragweed biotypes in response to a glyphosate application was evaluated by metagenomics analysis. Bacteria comprised approximately 96% of the total microbial community in both biotypes, and differences in the distribution of some microbes at the phyla level were observed. Select soil-borne plant pathogens (VerticilliumandXanthomonas) and plant-growth–promoting rhizobacteria (Burkholderia) present in the rhizosphere were influenced by either biotype or glyphosate application. We did not, however, observe large differences in the diversity or structure of soil microbial communities among our treatments. The results of this study indicate that challenging giant ragweed biotypes with glyphosate causes perturbations in rhizosphere microbial communities and that the perturbations differ between the susceptible and resistant biotypes. However, biological relevance of the rhizosphere microbial community data that we obtained by next-generation sequencing remains unclear.
Trophic island biogeography drives spatial divergence of community establishment
Authors: Harvey Eric , MacDougall Andrew S.
Published: April 2014

Food webs assemble via the interacting constraints of dispersal limitation and bottom‐up trophic dependencies where consumers can only establish after their resources have arrived. These factors can affect assembly by influencing the expression of the regional species pool in local patches, but how this unfolds mechanistically remains unclear. Here, we use a large‐scale grassland meta‐community experiment to demonstrate how the independent influences of spatial factors and bottom‐up constraints on insect trophic guilds interact to create divergent local insect communities. Bottom‐up trophic dependencies tightly controlled the composition and abundance of specialist trophic guilds, resulting in different communities among islands because producer communities were mainly determined by patch size contingencies. Spatial isolation controlled the composition and abundance of generalist trophic guilds, resulting in different insect communities among islands based on distance from mainland. These results demonstrate that neither diet‐based constraints nor the spatial characteristics of islands can predict the early structure of locally assembling food webs, with their establishment deriving instead from interactions between both processes.
Transgenerational phenotypic plasticity links breeding phenology with offspring life‐history
Authors: Richter-Boix Alex , Orizaola Germán , Laurila Anssi
Published: April 2014

The timing of seasonal life‐history events is assumed to evolve to synchronize life cycles with the availability of resources. Temporal variation in breeding time can have severe fitness consequences for the offspring, but the interplay between adult reproductive decisions and offspring phenotypes remains poorly understood. Transgenerational plasticity (TGP) is a potential mechanism allowing rapid responses to environmental change. Here, we investigated if experimentally delayed breeding induces TGP in larval life‐history traits in the moor frog (Rana arvalis). We found clear evidence of TGP in response to changes in breeding phenology: delayed breeding increased offspring development and growth rates in the absence of external cues. This constitutes the first unequivocal evidence for TGP in response to changes in breeding phenology in vertebrates. TGP can play an important role in adjusting offspring life‐history strategies to the environment they are most likely to encounter, and may constitute an important mechanism for coping with climate change.
The Public Health Foundation of Health Services for American Indians & Alaska Natives
Authors: Rhoades Everett R. , Rhoades Dorothy A.
Published: April 2014

The integration of public health practices with federal health care for American Indians and Alaska Natives (AI/ANs) largely derives from three major factors: the sovereign nature of AI/AN tribes, the sociocultural characteristics exhibited by the tribes, and that AI/ANs are distinct populations residing in defined geographic areas. The earliest services consisted of smallpox vaccination to a few AI/AN groups, a purely public health endeavor. Later, emphasis on public health was codified in the Snyder Act of 1921, which provided for, among other things, conservation of the health of AI/AN persons. Attention to the community was greatly expanded with the 1955 transfer of the Indian Health Service from the US Department of the Interior to the Public Health Service and has continued with the assumption of program operations by many tribes themselves. We trace developments in integration of community and public health practices in the provision of federal health care services for AI/AN persons and discuss recent trends.
Nitrogen Use in Durum and Selected Brassicaceae Oilseeds in Two‐Year Rotations
Authors: Allen B. L. , Lenssen A. W. , Sainju U. M. , Caesar-TonThat T. , Evans R. G.
Published: April 2014

Brassicaceae oilseeds can serve as potential feedstocks for renewable biofuels to offset demand for petroleum‐based alternatives. However, little is known about oilseed crop yield potential and N use in semiarid, wheat (Triticum spp.)‐based cropping systems that dominate the northern Great Plains (NGP). A 5‐yr study was conducted in northeast Montana to investigate the yield potential of a direct seeded system of durum (T. durum Desf.) in rotation with either chemical fallow or three Brassicaceae oilseeds: camelina [Camelina sativa (L.) Crantz], crambe (Crambe abyssinica Hochst. ex R.E. Fries), and canola‐quality Brassica juncea L. Overall, results from the study indicated that seed yield in the three Brassicaceae oilseeds tested in rotation with durum was related (P < 0.001; r2 = 0.68) to a nitrogen recovery index (NRI), indicating the importance of nitrogen use (NU) efficiency in dryland oilseed production, and that B. juncea generally used N more efficiently than crambe and camelina. Similarly, NRI was related (P < 0.001; r2 = 0.72) to grain yield in durum following oilseeds. Grain yield of durum following B. juncea was similar to durum following fallow and greater than durum following camelina or crambe. Durum following crambe tended to use N more inefficiently than durum following camelina, B. juncea, or fallow. Differences in yield and N use of durum and oilseeds varied among years, which underscores the need to further develop management tools to optimize durum‐oilseed cropping systems in highly variable rainfall environments typical of the NGP.
Effects of Long‐Term Fertilization on Soil Carbon and Nitrogen in Chinese Mollisols
Authors: Jiao Xiaoguang , Gao Chongsheng , Sui Yueyu , Lü Guohong , Wei Dan
Published: April 2014

Three field experiments were conducted to examine the influence of long‐term (30–31 yr) effect of fertilizer applications on soil C and N in the mollisols of Northeast China. Each experiment represented a different latitude range: low latitude (LatL), middle latitude (LatM) and high latitude (LatH). Four types of fertilizer applications were considered: (i) CK: unfertilized (control); (ii) NPK: balanced application of inorganic fertilizer nitrogen, phosphorus, potassium; (iii) M: application of organic manure; and (iv) NPKM: fertilizer nitrogen, phosphorus, potassium, plus organic manure. Compared with CK treatments, applications of fertilizers increased soil organic carbon (SOC), total nitrogen (TN), available nitrogen (AN), microbial biomass carbon (Cmic) and microbial biomass nitrogen (Nmic). On average compared with CK treatments, SOC in the NPK, M, and NPKM treatments increased by 2.74, 22.00, and 27.81%, respectively. Thus, applications of organic manure combined with inorganic fertilizers showed greater effects on the topsoil C and N content than inorganic fertilizers. Under the same fertilizer treatments, SOC, TN, Nmic, and Cmic contents were the lowest at LatM site. Available N content decreased for a latitude sequence of LatH > LatM > LatL for CK, M, and NPKM treatments and LatM > LatH > LatL for the NPK treatments. These results indicate that the magnitude of soil C and N among the three sites was not related to the latitude of the experiments.
Chlorophyll Meter Calibrations for Chlorophyll Content Using Measured and Simulated Leaf Transmittances
Authors: Raymond Hunt E. , Daughtry Craig S. T.
Published: April 2014

Konica‐Minolta SPAD‐502 leaf chlorophyll meters provide a relative value of leaf chlorophyll content, and from the literature, there are considerable variations among the calibration equations between total chlorophyll contents (μg chlorophyll a + b cm−2) and SPAD‐502 values. Our objective was to determine the leaf properties that contributed to the variations in calibration. We determined the internal calibration coefficient of five SPAD‐502 meters so that leaf transmittances in the red (650 nm) and near‐infrared (940 nm) could be used to calculate SPAD‐502 values. A leaf optics model, PROSPECT, was used to simulate transmittances and the chlorophyll–SPAD‐502 relationship for different leaf optical properties. Spectral and leaf data from maize (Zea mays L.) showed that PROSPECT predicted leaf transmittances within 2%. Maize leaf data used in the PROSPECT model predicted the relationship between chlorophyll content and the SPAD‐502 value, although a polynomial regression was a better fit to the data. There was a physical interaction between chlorophyll content and optical leaf structure affecting leaf transmittances, which is not in the equation for calculating SPAD‐502 values. Changing the PROSPECT leaf structure parameter resulted in different chlorophyll–SPAD‐502 meter relationships, which were similar to the measured range of variation from calibration equations found in the literature. If the red and near‐infrared transmittances are saved for each chlorophyll meter reading, then leaf radiative transfer models such as PROSPECT may be inverted to determine the actual leaf chlorophyll content.
Potassium Mobilization and Transformation in Red Paddy Soil as Affected by Rice
Authors: Li Xiaokun , Zhan Liping , Lu Jianwei , Liao Zhiwen , Li Jifu , Ren Tao , Cong Rihuan
Published: April 2014

A rhizobox experiment was conducted to study the effect of growing rice (Oryza sativa L.) on the movement and transformation of K in a red paddy soil. Results showed that K uptake by rice reduced the concentrations of soil water‐soluble K (Sol‐K), exchangeable K (Ex‐K), and non‐exchangeable K (Nonex‐K) in the root zone. Soil Sol‐K in non‐root‐zone compartment close to the root zone (0–6 cm) migrated toward the root zone, and soil Ex‐K (0–4 cm) and soil Nonex‐K (0–3 cm) was released into soil solution. As the rice growth progressed, soil Sol‐K, Ex‐K, and Nonex‐K in the root zone and soil Sol‐K in non‐root‐zone compartment close to the root zone (0–6 cm) continued to decrease. Decreases of soil Ex‐K and Nonex‐K in non‐root‐zone compartment extended from the root to 6 and 5 cm into the bulk soil, respectively. At the late grain‐filling stage, soil Sol‐K concentration in the root zone and non‐root‐zone compartment (0–6 cm) declined, and then remained stable, whereas Sol‐K in the non‐root zone (6–7 cm) kept diffusing toward the root zone. Soil Ex‐K and Nonex‐K in the root zone and non‐root‐zone compartment continued to reduce, and the decrease distance of soil Nonex‐K was extended to 6 cm. Within the whole season, soil Ex‐K and Nonex‐K were the main forms of K available to the plants, followed by Sol‐K. The information obtained in this study indicated that K fertilizer should be added to the place around the root zone.
Wheat and Soil Response to Wood Fly Ash Application in Contaminated Soils
Authors: Ochecova Pavla , Tlustos Pavel , Szakova Jirina
Published: April 2014

Wood fly ash from biofuel combustion plants is landfilled commonly as a waste, but research of this material is needed because it may reduce future fertilizer requirements. We investigated the effect of the ash application on potential changes in pH, nutrient, and potentially toxic element (in our case As, Cd, and Pb) content and mobility in soils. Wood fly ash in doses up to 1% (w/w) was added to spring wheat (Triticum aestivum L.) grown in potentially toxic element‐contaminated loam (Cambisol) and sandy clay loam (Fluvisol) soil material in 3‐yr pot experiment. The potentially toxic element contents in soils exceeded the maximum permissible limits for Czech soils, but the plant availability was, thanks to ash addition, limited. The effect of wood ash was greater in the Cambisol where Cd, Zn, and also Pb showed similar trends, and their content in plant decreased (Cd by 60%, Zn by 50%, and Pb by 45%), whereas the nutrient contents tended to increase in plants. Differences were usually insignificant (α = 0.05) in the Fluvisol between treatments, and Ca, Mg, and P contents were highest in the treatment without ash addition. The influence of soil changes on element uptake and distribution within the aboveground plant biomass was also observed. These findings are an important step on providing evidence of the benefits of using wood fly ash as a fertilizer supplement, because potentially toxic element contents in wheat grown in contaminated soils with ash addition were low and decreased, whereas the concentrations of major nutrients increased.
Short‐Term Effects of Cover Crops and Compaction on Soil Properties and Soybean Production in Illinois
Authors: Acuña Juan C. M. , Villamil María B.
Published: April 2014

Cover crops (CC) are being actively promoted in Illinois as a tool to improve soil properties and enhance crop performance and yield. Our goals were to assess the short‐term ability of radish (Raphanus sativus L. var. longipinnatus) and companion CC to improve (i) soil properties and (ii) soybean (Glycine max L. Merr.) growth and yield following compaction and CC treatments under conventional systems. We used a 6 × 3 factorial arrangement of the CC and compaction treatments in a completely randomized design with two replications in two independent year–locations hereby referred as environments. Cover crop treatments included radish alone “R”, and with rye (Secale cereale L.) “RR”, triticale (× Triticosecale ‘Presto’) “RTR”, buckwheat (Fagopyrum esculentum L. Moench) “RB”, or hairy vetch (Vicia villosa Roth) “RHV”, and a control with no cover crop “NCOV”. Compaction treatments were no compaction (Nc), and two levels of compaction achieved with a large tractor (LT) or a hauling truck (TK). Compaction was temporarily achieved and disappeared after the CC growing season. Cover crop treatments significantly lowered soil NO3–N compared to NCOV yet no further effect was evident on soils. Soybean yield for CC treatments were not different from control plots. Results from this study showed that one growing season was not enough time to evidence changes in soil properties related to cover cropping yet they were useful tools for retaining NO3–N in the system. In addition, following adequate management practices, CC should not affect soybean growth and yield.
Camelina Growing Degree Hour and Base Temperature Requirements
Authors: Allen B. L. , Vigil M. F. , Jabro J. D.
Published: April 2014

Oilseed crops show potential as biofuel feedstocks that can diversify spring wheat (Triticum aestivum L.) rotations in the northern Great Plains. Camelina (Camelina sativa L.) is a relatively new oilseed crop, with limited emergence information available. A 70‐d incubator study investigated the impact of temperature (0, 2, 4, and 16°C), seeding depth (3 and 6 mm), and cultivar (Blaine Creek, Calena, Celine, Ligena, and Suneson) on camelina emergence. After 68 d, camelina emergence at 0°C approached 100%. Base temperature averaged –0.70°C for the five cultivars tested and was 19% lower for the 6‐ than the 3‐mm seeding depth, although emergence was 11% sooner for the 3‐ than the 6‐mm seeding depth. About 1150 growing degree hours were required for 50% emergence, which corresponds to 29 March for camelina planted on 10 March, the earliest date when the average daily temperature exceeds the base temperature according to long‐term weather records for Sidney, MT. These results suggest that camelina emerges at temperatures below the freezing point of water and that early planting in spring would probably be limited by field access due to wet soil rather than the base temperature requirement. Although camelina emerges at temperatures below freezing under laboratory conditions, further investigation is warranted to confirm emergence under field conditions and determine the frost tolerance of camelina subsequent to germination.
Corn, Cotton, and Peanut Response to Tillage and Subsurface Drip Irrigation in North Carolina
Authors: Jordan D. L. , Johnson P. D. , Grabow G. L. , Corbett T.
Published: April 2014

Determining response of agronomic crops to subsurface drip irrigation (SDI) in conventional and reduced tillage systems is important in defining utility of SDI. Therefore, the objectives of this research were to define interactions of SDI and tillage with respect to yield and economic return of corn (Zea mays L.), cotton (Gossypium hirsutum L.), and peanut (Arachis hypogaea L.) planted in rotation. Research was conducted in two 4‐yr periods (2007–2010 and 2008–2011) in North Carolina using continuous strip tillage vs. continuous conventional tillage without irrigation or with SDI using a crop sequence of 1 yr of cotton, 2 yr of corn, followed by 1 yr of peanut. Corn, cotton, and peanut yields increased with SDI compared with no irrigation regardless of tillage system. Cotton and peanut yields were not affected by tillage system or the interaction of tillage and irrigation; corn yield was affected by this interaction. In the second year of corn, yield and economic return were higher in conventional tillage with SDI than strip tillage with SDI. Economic return for the sum of crops in the rotation was affected by the interaction of irrigation and tillage. Economic return was higher in both periods during each year corn was grown under SDI compared with non‐irrigated corn while higher economic returns for cotton and peanut under SDI were noted in one of two periods. When pooled over periods, crops, and tillage, economic return for SDI was US$1,552 ha−1 higher than non‐irrigated production over 4 yr.
Evaluating APSIM Maize, Soil Water, Soil Nitrogen, Manure, and Soil Temperature Modules in the Midwestern United States
Authors: Archontoulis Sotirios V. , Miguez Fernando E. , Moore Kenneth J.
Published: April 2014

The Agricultural Production Systems sIMulator (APSIM) is a cropping systems modeling platform that is used worldwide to address research questions related to agricultural systems. We explored whether APSIM performs well in the Midwest, so that the associated model capabilities would be available for application in this region. Our approach included calibration and testing of several APSIM models (maize [Zea mays L.], soil water, soil N, surface organic matter, manure, and soil temperature) and evaluation of model predictions against independent datasets. During calibration we developed local crop and soil parameters so that the model captured sufficiently well dynamics of soil water (root mean square error, RMSE = 0.032 mm mm−1), soil temperature (RMSE = 2.1°C), soil inorganic N dynamics (RMSE = 12.6 kg N ha−1), contrasting soil net N mineralization patterns under fresh and composted swine manure applications (RMSE = 13.6 kg N ha−1), crop phenology (RMSE = 1.52 d), leaf area index (RMSE = 0.60 m2 m−2), leaf N concentration (RMSE = 0.28 kg 100 kg−1), canopy N uptake (RMSE = 9.0 kg N ha−1), biomass production (RMSE = 0.77 Mg ha−1) and grain yield (RMSE = 0.53 Mg ha−1). The calibration protocol followed in this study is discussed in detail. The calibrated model was evaluated against independent data on grain yield (RMSE = 0.65 Mg ha−1), biomass production (RMSE = 1.1 Mg ha−1) and LAI (RMSE = 1.14 m2 m−2), showing very acceptable performance, especially in addressing yield‐N relationships. Therefore APSIM proves to be a reliable model that can be used as a research and decision tool to enhance Midwestern production systems.
CA-125 of fetal origin can act as a ligand for dendritic cell-specific ICAM-3-grabbing non-integrin
Authors: Mitić Ninoslav , Milutinović Bojana , Janković Miroslava
Published: April 2014

CA-125 (coelomic epithelium-related antigen) forms the extracellular portion of transmembrane mucin 16 (MUC16). It is shed after proteolytic degradation. Due to structural heterogeneity, CA-125 ligand capacity and biological roles are not yet understood. In this study, we assessed CA-125 as a ligand for dendritic cell-specific ICAM-3-grabbing non-integrin (DC-SIGN), which is a C-type lectin showing specificity for mannosylated and fucosylated structures. It plays a role as a pattern recognition molecule for viral and bacterial glycans or as an adhesion receptor. We probed a human DC-SIGN-Fc chimera with CA-125 of fetal or cancer origin using solid- or fluid-phase binding and inhibition assays. The results showed that DC-SIGN binds to CA-125 of fetal origin and that this interaction is carbohydrate-dependent. By contrast, cancerderived CA-125 displayed negligible binding. Inhibition assays indicated differences in the potency of CA-125 to interfere with DC-SIGN binding to pathogen-related glycoconjugates, such as mannan and Helicobacter pylori antigens. The differences in ligand properties between CA-125 of fetal and cancer origin may be due to specificities of glycosylation. This might influence various functions of dendritic cells based on their subset diversity and maturation-related functional capacity.
Monitoring of membrane phospholipid scrambling in human erythrocytes and K562 cells with FM1-43 — a comparison with annexin V-FITC
Authors: Wróbel Anna , Bobrowska-Hägerstrand Małgorzata , Lindqvist Christer , Hägerstrand Henry
Published: April 2014

The styryl dye FM1-43 becomes highly fluorescent upon binding to cell membranes. The breakdown of membrane phospholipid asymmetry in ionophore-stimulated T-lymphocytes further increases this fluorescence [Zweifach, 2000]. In this study, the capacity of FM1-43 to monitor membrane phospholipid scrambling was explored using flow cytometry in human erythrocytes and human erythrocyte progenitor K562 cells. The Ca2+-dependent phosphatidylserine-specific probe annexin V-FITC was used for comparison. The presented data show that the loss of phospholipid asymmetry that could be induced in human erythrocytes by elevated intracellular Ca2+ or by structurally different membrane intercalated amphiphilic compounds increases the FM1-43 fluorescence two- to fivefold. The profile of FM1-43 fluorescence for various treatments resembles that of phosphatidylserine exposure reported by annexin V-FITC. FM1-43 detected the onset of scrambling more efficiently than annexin V-FITC. The amphiphile-induced scrambling was shown to be a Ca2+-independent process. Monitoring of scrambling in K562 cells caused by NEM-induced Ca2+-release from intracellular stores and by Ca2+ and ionophore A23187 treatment showed that the increase in FM1-43 fluorescence correlated well with the number of annexin V-FITC-detected phosphatidylserine-positive cells. The results presented here show the usefulness of FM1-43 as a Ca2+-independent marker of dissipation in asymmetric membrane phospholipid distribution induced by various stimuli in both nucleated and non-nucleated cells.
A Review of Missing Data Handling Methods in Education Research
Authors: Cheema Jehanzeb R.
Published: April 2014

Missing data are a common occurrence in survey-based research studies in education, and the way missing values are handled can significantly affect the results of analyses based on such data. Despite known problems with performance of some missing data handling methods, such as mean imputation, many researchers in education continue to use those methods as a quick fix. This study reviews the current literature on missing data handling methods within the special context of education research to summarize the pros and cons of various methods and provides guidelines for future research in this area.
“Remove Your Mask”: Character Psychology in Introspective Musical Theatre – Sondheim’sFollies, LaChiusa’sThe Wild Party, and Stew’sPassing Strange
Authors: Roost Alisa
Published: April 2014

ABSTRACT:

While earlier musicals, which developed popular songs, tended to focus on romance, differing backgrounds of the two members of a romantic couple, and their acceptance of each other and into a community, introspective musicals, which Stephen Sondheim pioneered after rock ’n’ roll began to define popular music, often dramatize psychological layers by exploring the discrepancy between the persona a character constructs and the character’s true inner self. I examine the way introspective musicals construct a paradigm of psychological growth, which usually involves characters’ creating strong masks/personae to hide their authentic selves and then ultimately gaining the courage to remove those masks. By looking at the construction of personae and their eventual attempts to accept emotional vulnerability – in Stephen Sondheim’s Follies, Michael John LaChiusa’s The Wild Party, and Stew’s Passing Strange – I explicate the way smaller, post-Sondheim musicals have shifted toward dramatizing an isolated character’s emotional development.
High-resolution ice-thickness mapping in South Greenland
Authors: Morlighem M. , Rignot E. , Mouginot J. , Seroussi H. , Larour E.
Published: April 2014

Airborne radar sounding is difficult in South Greenland because of the presence of englacial water, which prevents the signal from reaching the bed. Data coverage remains suboptimal for traditional methods of ice-thickness and bed mapping that rely on geostatistical techniques, such as kriging, because important features are missing. Here we apply two alternative approaches of high-resolution (~300m) ice-thickness mapping, that are based on the conservation of mass, to two regions of South Greenland: (1) Qooqqup Sermia and Kiattuut Sermiat, and (2) Ikertivaq. These two algorithms solve optimization problems, for which the conservation of mass is either enforced as a hard constraint, or as a soft constraint. For the first region, very few measurements are available but there is no gap in ice motion data, whereas for Ikertivaq, more ice-thickness measurements are available, but there are gaps in ice motion data. We show that mass-conservation algorithms can be used as validation tools for radar sounding. We also show that it is preferable to apply mass conservation as a hard constraint, rather than a soft constraint, as it better preserves elongated features, such as glacial valleys and ridges.
Plastic faulting in saltwater ice
Authors: Golding Narayana , Snyder Scott A. , Schulson Erland M. , Renshaw Carl E.
Published: April 2014

Compression experiments on laboratory-grown columnar S2 saltwater ice loaded triaxially through proportional loading atT= –20°C at applied strain rates ofdemonstrate that plastic (P) faulting is a mode of failure in saltwater ice when rapidly loaded under a high degree of confinement. In terms of microstructure, mechanical behavior and strength, saltwater ice that fails via P-faulting is almost indistinguishable from columnar S2 freshwater ice that fails via P-faulting loaded under the same conditions. The results also demonstrate that saltwater ice loaded rapidly may exhibit yet another mode of failure, in addition to P-faulting, through what appears to be a mechanism of pore collapse.
‘As If’ There Were a ‘Jew’: The (non)Existence of Deconstructive Responsibility
Authors: Gaon Stella
Published: April 2014

The argument of this paper hinges on Derrida's relation to Judaism as a religious heritage and/or as an essential experience. If he can be said to ‘appropriate his Jewish roots’ at all, as Colby Dickinson (2011) has recently proposed, this is not because Derrida concurs that all belief in an ultimate reality (‘as such’) must now be understood in merely conditional terms (‘as if’). Rather, it is because Derrida deconstructs the difference between the Jew and the non-Jew, along with the differences between the ‘as if’ and the ‘as such’ and the performative and the constative, in his very demonstration of the impossibility of ‘being-jewish’. Dickinson thus misunderstands the way in which Derrida appropriates Kant's regulative ‘as if’, and thus misrepresents what is at stake in Derrida's ‘faith’ in ‘Jewishness’. What is at stake is what Derrida calls deconstructive responsibility, and it takes the form of a radical fidelity to the principle of reason (to an ‘unconditional theoreticism’). This responsibility, paradoxically, demands and impels the interrogation of critical thinking itself, with its principles, its essences and its identities. Accordingly, Derrida interrupts both the ‘as such’ and the ‘as if’ with the ‘if’ of a dangerous ‘perhaps’.
Comparative Evaluation of Common Savannahgrass on a Range of Soils Subjected to Different Stresses I: Productivity and Quality
Authors: Springer Raymond , Eudoxie Gaius , Gouveia Gregory
Published: April 2014

Turfgrass growth, performance and quality are affected by abiotic stress factors and are of primary concern for persons managing turfgrass areas under seasonal tropical climates. Under these conditions, common Savannahgrass (SG) may have a performance advantage over imported hybrid turfgrasses. A greenhouse study was conducted to comparatively evaluate the performance of tropical turfgrasses exposed to water and compaction related stresses across a range of soils, with or without the addition of a surface sand layer. Turfgrass productivity and quality was monitored over a four-month growth period. Clipping yield (CY) was lower at the higher compaction effort for all turfgrasses, but across all stresses, drought (D) and waterlogging (WL) resulted in lower CY. Values were significantly lower under D. SG had the highest clipping yield across all soils. The chlorophyll index (CI) was lower for all turfgrasses under water-induced stress compared to compaction stresses. SG had a significantly higher CI across all stress treatments. Correlation analysis showed a positive (r² = 0.420) and significant (p < 0.05) relationship between CY and CI. Similar to CI, stress type influenced turfgrass visual quality (VQ), with D stress, resulting in the lowest VQ rating among turfgrasses. Bermudagrass (BG) had the lowest VQ across all stress treatments, whilst, comparatively, Zoysiagrass (ZG) had significantly higher VQ under high compaction (HC), low compaction (LC) and WL stress. Overall, SG showed a higher level of tolerance to applied stresses and warrants greater attention as a potential turfgrass under tropical conditions.
STAT3 Activity and Function in Cancer: Modulation by STAT5 and miR-146b
Authors: Walker Sarah , Xiang Michael , Frank David
Published: April 2014

The transcription factor STAT3 regulates genes that control critical cellular processes such as proliferation, survival, pluripotency, and motility. Thus, under physiological conditions, the transcriptional function of STAT3 is tightly regulated as one part of a complex signaling matrix. When these processes are subverted through mutation or epigenetic events, STAT3 becomes highly active and drives elevated expression of genes underlying these phenotypes, leading to malignant cellular behavior. However, even in the presence of activated STAT3, other cellular modulators can have a major impact on the biological properties of a cancer cell, which is reflected in the clinical behavior of a tumor. Recent evidence has suggested that two such key modulators are the activation status of other STAT family members, particularly STAT5, and the expression of STAT3-regulated genes that are part of negative feedback circuits, including microRNAs such as miR-146b. With attention to these newly emerging areas, we will gain greater insight into the consequence of STAT3 activation in the biology of human cancers. In addition, understanding these subtleties of STAT3 signaling in cancer pathogenesis will allow the development of more rational molecular approaches to cancer therapy.