bluuebunny/crossref_metadata_2025 huggingface dataset:
Atrazine nanoencapsulation improves pre‐emergence herbicidal activity against Bidens pilosa without enhancing long‐term residual effect on Glycine max
Authors: Preisler Ana C , Pereira Anderson ES , Campos Estefânia VR , Dalazen Giliardi , Fraceto Leonardo F , Oliveira Halley C
Published: May 2019

BACKGROUND

Poly(ϵ‐caprolactone) nanocapsules (NC + ATZ) are an efficient carrier system for atrazine and were developed as an alternative to reduce the harmful environmental effects of this herbicide. Here, we analyzed the pre‐emergence herbicidal activity of NC + ATZ against Bidens pilosa and evaluated its residual effect on soybean plants after different periods of soil treatment with the formulations.

RESULTS

In contrast to non‐nanoatrazine, NC + ATZ treatment led to very high mortality rates of B. pilosa seedlings even after a tenfold dilution, which suggests that atrazine nanoencapsulation improved its pre‐emergence herbicidal activity. In a short‐term assay (17 days), soil treatment with all atrazine‐containing formulations resulted in intense toxicity to soybean plants. NC + ATZ at 200 g ha−1 had the same inhibitory effects on the physiological and growth parameters of soybean plants compared with non‐nanoatrazine at 2000 g ha−1, which suggests that atrazine nanoencapsulation increased the short‐term residual effect of the herbicide. In a long‐term assay (60 days), a gradual recovery of soybean plants from atrazine phytotoxicity was observed. When comparing the effects of nano‐ and non‐nanoatrazine at the same concentrations, the growth and physiological parameters of soybean plants were mainly affected to the same extent. This indicates that encapsulation of atrazine into poly(ϵ‐caprolactone) nanocapsules did not enhance the long‐term residual effect of the herbicide on soybean.

CONCLUSION

NC + ATZ could be applied for efficient weed control without additional phytotoxicity to susceptible crops compared with non‐nanoatrazine, provided that a safe interval is respected from atrazine application to sowing. © 2019 Society of Chemical Industry
Synergistic Effect of Cr3+ on Layered Double Hydroxide Supported Cu0 Nanoparticles for the Oxidation of Alcohols and Hydrocarbons
Authors: Choudhary Anu , Sharma Nitika , Sharma Chandan , Jamwal Babita , Paul Satya
Published: May 2019

Chromium(III)‐doped layered double hydroxide supported copper nanoparticles (Cr3+‐Cu0/LDH) has been prepared as an efficient and reusable catalyst using simple and versatile synthetic method. Effect of doping of Cr3+ to the layered double hydroxide supported Cu0 nanoparticles was evaluated for the oxidation of alcohols and hydrocarbons by varying the amount of Cr3+ loading in the catalyst. The catalyst with Cu:Cr ratio= 1:1 afforded highest catalytic activity among the synthesized catalysts towards the oxidation using TBHP (tBuOOH) in aqueous medium and was structurally characterized by Fourier Transform Infrared Spectroscopy (FTIR), X‐Ray Diffraction Spectroscopy (XRD), Field Emission Gun‐Scanning Electron Microscopy (FEG‐SEM), Energy‐dispersive X‐Ray Spectroscopy (EDX), High Resolution‐Transmission Electron Spectroscopy (HR‐TEM), Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP‐AES) and X‐Ray Photoelectron Spectroscopy (XPS). The high activity and selectivity was assigned to the synergistic electronic interaction between copper(0) nanoparticles and chromium(III) ions based on experimental data and XPS results. Moreover, the high stability of Cu0 and Cr3+ in the catalyst was attributed to the strong metal‐support interactions, which make the catalyst recyclable upto five runs.
Development of analytical method by free solution capillary electrophoresis for furosemide under stress degradation
Authors: de Souza Aline , Kedor‐Hackmann Erika Rosa Maria , Santoro Maria Inês Rocha Miritello , Aurora‐Prado María Segunda
Published: May 2019

A fast, economical, precise and accurate free solution capillary electrophoresis method with photodiode array detector was developed and validated for the determination of furosemide in tablets. The separation was achieved by using a fused silica capillary column with (total length of 30.2 cm × 50.0 µm id). The optimum separations conditions were: 2.0 mmol L−1 sodium tetraborate buffer solution, pH 9.3 and 10% methanol; hydrodynamic injection 3.45 kPa/5 s; voltage and temperature set at +25 kV and 25°C, respectively, and UV detection at 273 nm. The method allowed the quantitative determination of furosemide and showed good linearity (70.0 to 130.0 µg mL−1) with a correlation coefficient (>0.99). The migration time was 1.8 min. Accuracy repeatability and intermediate precisions were less than 5.0% and the average recovery, 102.1%. Degradation was tested under neutral, acidic and alkaline hydrolysis, as well as under chemical oxidation, thermal and photodegradation. The method was specific and allowed the detection of three potential degradation products with migration times of 1.3, 2.0, and 2.2 min, respectively under oxidation test. Also, one potential degradation product under acidic hydrolysis (2.0 min). The method can be used in quality control laboratories and also as a stability‐indicating method for furosemide in tablets.
The Ghosts of Wagnerism: Organized Labour, Union Strategies, and the Charter of Rights and Freedoms
Authors: Smith Charles W.
Published: May 2019

Wagnerism has been at the centre of Canadian labour relations since the end of World War II. Wagnerism rests on a so-called balance between workers and employers. Between 2007 and 2015, the Supreme Court of Canada has ruled that the constitution includes protections for good faith collective bargaining and to strike. In these cases, the Court stated that it is not constitutionally enshrining Wagnerism, yet it also leaned heavily on Wagner principles in arriving at its decisions. Building on interviews with national union leaders, I argue that the ambiguity between the Court’s decisions and Wagnerism has left workers uncertain about how these rights alter the material conditions of unions. I conclude that the court’s embrace of labour freedoms will only have material benefit if workers are willing to use these newfound freedoms to build working class capacities to directly confront ongoing attacks by governments and employers on core union freedoms.
IV. Response: Contemplative Pedagogy as Engaged Learning
Authors: Locklin Reid B.
Published: May 2019

I am grateful to be given the opportunity to read and to respond to these rich reflections on the practice of contemplative pedagogy. Like Maureen Walsh, and possibly Brian Robinette before his sabbatical transformation, I have usually identified myself as a member of the “loyal opposition” of this particular teaching tool. I have tried to remain grudgingly attentive to its strongest advocates in the comparative theology circles in which I travel, while at the same time shaking my head and sighing a bit to myself at what I perceive as a wild-eyed enthusiasm bordering on evangelism. It probably does not help that I am not personally prone to contemplative experience, nor that the Hindu paraṃparā with which I have associated for several decades has, at least in part, constructed its distinctive teaching tradition as a critique of meditative experience (anubhava) as means or end of liberation.
THE OPTIONS BY CONTEXT APPROACH: A PARADIGM SHIFT IN AGRONOMY
Authors: SINCLAIR FERGUS , COE RIC
Published: May 2019

Innovation in agronomy by large numbers of smallholder farmers will need to accelerate if global commitments to end hunger are to be achieved in the face of major climate and other global change that are both caused by, and impact, agriculture. Conventional research and development in agronomy have involved a research process that produces technologies, which are then promoted for uptake by large numbers of farmers through extension, with both research and extension phases being more or less participatory. Recent research, including key contributions to this special issue, reveals that the performance of many technology options varies hugely across the geographies over which development programmes operate, depending on social, economic and ecological context. This severely limits the value of attempting to produce recommendations for large areas and numbers of farmers and identifies the need for new ways of supporting innovation that address the real-world heterogeneity of farmer circumstances. Addressing this widespread phenomenon of option by context interaction (OxC) has profound implications for how agronomic research and development are organised. Papers in this special issue show the nature and implications of such interactions and suggest ways in which research and development systems need to respond in order to support locally relevant innovation. It is evident that a paradigm shift is well underway, with researchers embracing new modes of thinking and action required to address OxC interactions, but these also need to be taken up and further developed by extension and change agents in the public and private sector. It is only through continued co-development of methods involving both these constituencies, working closely with farmers that sufficient progress is likely to be made for smallholder farming to keep pace with global demand for food without further damaging the environmental resources upon which production is based.
Military nuclear relations between the United States and Great Britain under the terms of the McMahon Act, 1946–1958
Authors: Ball S. J.
Published: May 2019

This article takes a fresh look at Anglo-American nuclear relations between 1946 and 1958. It concentrates on the relationship between the military establishments of the two countries in general and the ties between the United States air force and the Royal Air Force in particular. The article argues that an understanding of military relations is essential for an understanding of the high politics of the nuclear relationship. It is shown that senior officers in the armed services were the main ‘functional elite’ dealing with nuclear delivery systems and the planning for their use. Relations between these groups were personally and institutionally close and on the whole cordial. In Britain the link sustained optimism about the possibility of close nuclear co-operation in the 1940s and early 1950s and suppressed fears about the loss of nuclear independence in the late 1950s. In the United States it was recognized that military relations were an important channel through which to influence British nuclear policy. The article offers accounts, based on new archival research, of the nuclear aspect of the October 1947 Pentagon talks on the Middle East, Churchill's visit to the United States in January 1952 and the first Anglo-American joint nuclear targeting agreement – the Wilson/Alexander agreement of 12 March 1954. It reveals for the first time details of Plans E and X which equipped the RAF with American atomic and thermonuclear weapons between 1955 and 1958. The article concludes that the British nuclear force was becoming subordinated to the United States even before negotiations about Thor, Skybolt and Polaris missiles became central to the relationship.
Selected Ordovician Trilobites from the Lake St. John District of Quebec and Their Bearing on Systematics
Authors: Lespérance Pierre J. , Desbiens Sylvain
Published: May 2019

The thorax ofHypodicranotushas ten segments and a spine on the eighth. The ages ofErratencrinuruss.l.spicatusandErratencrinurus(Erratencrinurus?)vigilansin the Lake St. John district do not confirm their temporal roles leading to subgenera ofErratencrinurus, as has been recently suggested. Phylogenetic analyses of large data sets of species previously referred toEncrinuroidesandPhysemataspisyield a minimal length cladogram containing 18 species.Encrinuroidesis restricted to four species, two of which have biogeographic affinities with Iapetus. These results lead to three clades, named theWalencrinuroidesn. gen. clade,Frencrinuroidesn. gen. clade, and finally thePhysemataspisclade, with an enlarged concept of the genus with the erection ofPhysemataspis(Prophysemataspis) n. subgen. These last three clades are restricted to North America and Scotland, with alternating predominance of one region.Walencrinuroidess.l.gelaisin. gen. n. sp. is described. New morphological data onErratencrinuruss.l.spicatusconfirm its close relationship with the clades discussed above. Data are insufficient for phylogenetic analysis of selected cheirurine species here surveyed. Eye position, glabellar segmentation, and pygidial shape differentiate the generaCeraurusandGabriceraurus; emended diagnoses of these genera are presented.Ceraurus globulobatusandC. matranserisare distinct, but morphologically close to one another. The status ofGabriceraurus dentatuscan be stabilized on its extant types.
Early Cambrian Trilobites from the Shackleton Limestone of the Central Transantarctic Mountains
Authors: Palmer Allison R. , Rowell Albert J.
Published: May 2019

We document and describe the trilobite faunas of the Lower Cambrian Shackleton Limestone. The faunas include taxa of Atdabanian, Botomian and possible Toyonian ages and have affinities with those known previously from Gondwana or peri-Gondwana terranes. The geographic distribution of these organisms reveals a large measure of faunal connectedness around the margin of this vast supercontinent in Early Cambrian time. This connectedness extended even to taxa that inhabited shallow-water carbonate shelf environments, because the Shackleton Limestone accumulated in a variety of shallow subtidal and peritidal settings along the ocean-facing margin of the East Antarctic craton, subsequent to a Neoproterozoic rifting event. Although the fossilized Shackleton Limestone fauna is dominated by archaeocyathans, trilobites are common locally. We describe the remains of 35 trilobite taxa from 32 collecting localities. One species,H. granulosa, is assigned to the new genusHolyoakia;the remaining new species arePagetides (Discomesites) spinosus, Lemdadella antarcticae, Kingaspis(?)convexus, Yunnanocephalus longioccipitalis, andOnchocephalina(?)spinosa.
Must Liberal Citizens Be Reasonable?
Authors: Strike Kenneth A.
Published: May 2019

Political Liberalism was motivated by Rawls's belief that A Theory of Justice inadequately treated the problem of stability. Theory of Justice grounded justice in a comprehensive doctrine, ethical liberalism. In a society wherein citizens hold a variety of reasonable comprehensive doctrines, such a theory of justice is unstable. Political Liberalism seeks a free-standing political theory compatible with many reasonable comprehensive doctrines.

Reasonableness involves reciprocity which in turn requires the acceptance of the burdens of judgment. We cannot respect other citizens if we regard them or their comprehensive doctrines as pernicious or stupid. While we may continue to accept our own comprehensive doctrine, reciprocity and tolerance require that we recognize that other doctrines and those who hold them are reasonable.

Callan claims that Rawls's project fails. Ethical liberalism views autonomy as essential to a good life. However, if the burdens of judgment are a prerequisite for reciprocity, political liberalism must also value autonomy, if not as an essential part of a good life, then as a public good. Any view of political socialization robust enough to secure a recognition of the burdens of judgment must also produce habits of mind tantamount to autonomy. If so, political liberalism collapses into ethical liberalism. Their implications for political socialization are indistinguishable. Many comprehensive doctrines, paradigmatically religious ones, will be weakened by these requirements for political socialization.

Callan's argument points to a tension in liberal views of education. A liberalism that promotes a thick liberal culture will appear intolerant to many with religious commitments.
Diverse Mutations in the Acetolactate Synthase Gene Confer Chlorsulfuron Resistance in Kochia (Kochia scoparia) Biotypes
Authors: Guttieri Mary J. , Eberlein Charlotte V. , Thill Donald C.
Published: May 2019

The DNA sequence of an 83-base pair region of the acetolactate synthase (ALS) gene was compared for 10 chlorsulfuron-resistant (R) and three chlorsulfuron-susceptible (S) kochia biotypes. Point mutation in the codon for the proline residue at position 173 in Domain A of the ALS protein was observed in seven of 10 R biotypes. Among these seven R biotypes, mutation to threonine, serine, arginine, leucine, glutamine, and alanine was identified. The mechanism of resistance was determined for the R biotypes that did not have mutation in Domain A; all were resistant due to modified ALS, which indicated that at least one non-Domain A mutation site for resistance exists in kochia. Sequence results indicate that multiple mutations for resistance have occurred, and that geographically widespread ALS-inhibitor resistance in kochia is not the result of a single resistance allele.
Spray Deposition of Fenoxaprop and Imazamethabenz on Wild Oat (Avena fatua) as Influenced by Environmental Factors
Authors: Xie Haisheng S. , Caldwell Brian C. , Hsiao Andrew I. , Quick William A. , Chao Jian Fu
Published: May 2019

The effect of soil moisture, temperature, and light intensity on the spray deposition of fenoxaprop and imazamethabenz applied to wild oat plants was examined by using fluorescent tracer dye. Based on either biomass or total leaf area, the apparent deposition of the two herbicides diminished in the following order: shading > low temperature ≥ drought ≥ “optimum” > high temperature. The enhanced phytotoxicity of both herbicides under shading could be associated with increased spray deposition; and reduced fenoxaprop phytotoxicity under high temperature stress could be related to reduced deposition. Changes in spray deposition were attributed mainly to differences in herbicide interception due to altered plant morphology. Reduced retention for both herbicides was exhibited only in the plants grown at high temperature. Under “optimum” conditions, fenoxaprop phytotoxicity was directly associated with leaf orientation and thus with the proportion of projected leaf area at the time of herbicide spraying. Given similar application conditions, spray deposition of fenoxaprop and imazamethabenz on wild oat could be estimated by determining the ratio of the projected leaf area, as measured by an image analyzer, to the total leaf area.
Phytotoxic Interaction of Tridiphane and Metribuzin in Metribuzin Sensitive and Tolerant Soybean (Glycine max) and Tomato (Lycopersicon esculentum)
Authors: Gaul Sonia O. , Stephenson Gerald R. , Solomon Keith R.
Published: May 2019

The joint action of metribuzin and tridiphane was investigated in metribuzin-tolerant (T) and metribuzin-susceptible (S) soybean and tomato cultivars within species, respectively, under growth room studies. Maple Arrow (T) and Maple Amber (S) exhibited similar tolerance to tridiphane applied at soybean emergence. Vision (T) tomato was more sensitive to tridiphane than was Springset (S) tomato, the reverse of the relative tolerance to metribuzin. A phytotoxic interaction was demonstrated following application of tridiphane and metribuzin at the respective rates (kg ai ha−1) of 0.1 and 1.1 in Maple Arrow (T) soybeans, 0.05 and 0.25 in Maple Amber (S) soybeans, and 0.25 and 0.2 in Springset (S) tomato. Tridiphane applied 1 or 4 h before metribuzin caused the greatest phytotoxicity in Maple Amber (S) soybeans. Soybean field results generally supported those of growth-room studies. Foliar spray pretreatment with tridiphane increased total radioactivity in Springset (S), decreased the total root radioactivity and increased total shoot radioactivity in both Vision (T) and Springset (S) and decreased metabolism of metribuzin to water soluble conjugates in Springset (S) roots over 24 h following14C-metribuzin application to roots of intact tomato seedlings. The increased uptake, translocation to the shoots, and decreased root metabolism of metribuzin in Springset when pretreated with tridiphane could explain the phytotoxic interaction (which was unexpected, based only on the glucose detoxification pathway of metribuzin in tomato).
Cultural Practices in Wheat (Triticum aestivum), on Weeds in Subsequent Fallow and Sorghum (Sorghum bicolor)
Authors: Wicks Gail A. , Martin Duane A. , Mahnken Garold W.
Published: May 2019

The effect of herbicide and urea-ammonium nitrate (UAN) combinations on winter wheat injury in absence of noncompetitive weeds and weed control during a winter wheat-fallow and a winter wheat-sorghum-fallow rotation were investigated. Winter wheat was planted at different dates to obtain different growth stages for spraying in the spring. Winter wheat produced greater grain yields when planted Sept. 15 or Sept. 25, 1987, 1988, and 1989 vs. Sept. 1 at North Platte, NE, while at Sidney, NE, grain yield was higher in wheat planted on Sept. 10 or Sept. 20, 1988, compared to Aug. 26. Spring-applied UAN increased grain yield on wheat planted Sept. 10 compared to no UAN in 1988–89 at Sidney, but not in 1987–88, while at North Platte, grain yields were not affected by UAN. At Sidney 2,4-D ester at 0.6 kg ae ha−1, 2,4-D amine plus dicamba at 0.3 plus 0.1 kg ae ha−1, metsulfuron at 0.007 kg ai ha−1plus 0.25% nonionic surfactant (NIS), and metsulfuron plus 2,4-D ester at 0.007 plus 0.3 kg ha−1plus NIS decreased grain yields compared to one handweeding. At North Platte in 1988–89, when UAN was applied with 2,4-D ester, 2,4-D amine plus dicamba, or metsulfuron plus 2,4-D plus NIS grain yields were reduced compared to the handweeded check on wheat planted Sept. 15. Occasionally, metsulfuron plus 2,4-D ester plus NIS treated wheat yielded less grain than metsulfuron plus NIS treated wheat. One or more herbicide treatments reduced wheat grain yields 4 of 15 application dates. Crop injury was related to growth stage and health of winter wheat when treatments were applied. Wheat under stress was more susceptible to herbicide damage than healthy wheat. Metsulfuron and metsulfuron plus 2,4-D controlled kochia, tumble thistle, and redroot pigweed better after wheat harvest than 2,4-D or 2,4-D plus dicamba at North Platte, but allowed summer annual grass weeds to grow. Yields of grain sorghum planted after a 10-mo fallow period were higher following winter wheat treated with three of four herbicides than the handweeded treatment.
Approaches for Improving Crop Competitiveness Through the Manipulation of Fertilization Strategies
Authors: Di Tomaso Joseph M.
Published: May 2019

Weeds are often more competitive with crops at higher soil nutrient levels. This can result in increased dependency on herbicides and tillage to maintain adequate weed control. A number of studies have shown weeds accumulate higher concentrations of nitrogen, phosphorus, potassium, calcium, and magnesium than crops, thus depleting soil nutrient levels more quickly and reducing crop yield. Understanding basic mechanisms and timing of nutrient uptake in weeds and crops can lead to fertilization strategies which will enhance the competitive ability of crops while reducing interference from weeds. Such strategies can include deep band application of fertilizers to the crop row, as opposed to broadcast applications. Banding techniques also reduce the potential for nitrate contamination of surface or groundwater. The addition of nitrification inhibitors or increasing the proportion of nitrogen as ammonium or urea in fertilizer mixtures can restrict growth of ammonium- or urea-sensitive weeds. The timing of fertilizer applications can take advantage of maximal rates of nutrient uptake into crop roots at specific developmental stages. In addition, nutrient use efficiency can be enhanced by choosing appropriate crop cultivars, maintaining effective weed control practices, or altering row spacing or seeding rate to increase accumulation of nitrogen, phosphorus, and potassium in crops.
Exploiting Weed Seed Dormancy and Germination Requirements through Agronomic Practices
Authors: Dyer William E.
Published: May 2019

Many common agronomic practices affect weed seed dormancy and germination by influencing the microenvironmental and edaphic conditions surrounding seeds in soil. Factors such as light penetration, soil water content, soil fertility, and temperature are modified by tillage, planting, harvesting, and other production practices, resulting in enhanced or depressed weed seed germination. Changes in these environmental factors may also indirectly lead to alterations in phytohormone concentrations during seed development, which can subsequently affect dormancy status of the mature seed. Integrated approaches that place priority on depleting weed seed banks through interfering with dormancy or germination requirements have strong potential to enhance weed management aspects of agricultural systems.
Giant Foxtail (Setaria faberi) Resistance to Aryloxyphenoxypropionate and Cyclohexanedione Herbicides
Authors: Stoltenberg David E. , Wiederholt Ronald J.
Published: May 2019

A giant foxtail (PCW1) population putatively resistant to fluazifop-P and sethoxydim was identified in a carrot, onion, and corn cropping system in Wisconsin during 1991. Previous, extensive use of fluazifop and fluazifop-P over several years imposed a high level of selection intensity on grass weeds. In a field experiment, fluazifop-P, sethoxydim, and quizalofop at recommended dosages resulted in 58, 53, and 45% plant survival, respectively, within the PCW1 giant foxtail population; no plants survived treatment with clethodim or nicosulfuron, and few plants survived treatment with imazethapyr at recommended dosages. Based on shoot dry biomass reduction in greenhouse experiments, a PCW1 giant foxtail biotype had 16-, > 9-, 4.9-, and 4.2-fold resistance to fluazifop-P, diclofop, quizalofop, and fenoxaprop, respectively, relative to a giant foxtail (AC1) accession that was susceptible to aryloxyphenoxypropionate (APP) and cyclohexanedione (CHD) herbicides. The PCW1 biotype had 134-fold resistance to sethoxydim and slight and inconsistent resistance to clethodim. The PCW1 biotype and AC1 accession were equally susceptible to imazethapyr, linuron, and oxyfluorfen. Based on plant survival, a PCW1 giant foxtail accession had 25- and > 143-fold resistance to fluazifop-P and sethoxydim, respectively, relative to the AC1 accession. The selection intensity associated with repeated use of fluazifop and fluazifop-P over 5 yr contributed to the cross-resistance of PCW1 giant foxtail to APP and CHD herbicides.
Uptake, Translocation, and Metabolism of14C-MSMA in Organic Arsenical-Resistant and -Susceptible Mississippi Biotypes of Common Cocklebur (Xanthium strumariumL.)
Authors: Nimbal Chandrashekhar I. , Wills Gene D. , Duke Stephen O. , Shaw David R.
Published: May 2019

The uptake, translocation, and metabolism of14C-MSMA in organic arsenical-resistant (R) and -susceptible (S) Mississippi biotypes of common cocklebur were investigated. The two biotypes did not differ significantly with respect to either uptake, total translocation, or translocation pattern of14C-MSMA plus its radiolabeled metabolites regardless of whether plants were pre-treated with 1.12 kg ai ha−1of unlabeled MSMA or treated only with radiolabeled material. Absorption of14C-MSMA was greater in unlabeled MSMA-pretreated plants than untreated plants, whereas the percent of total absorbed14C-MSMA that was translocated out of the14C-MSMA-treated leaf was almost the same in MSMA-pretreated and untreated plants. Qualitative detection of14C-MSMA distribution by autoradiographs confirmed quantitative results obtained with radioassays. Herbicide metabolism in the14C-treated leaf showed that MSMA was not readily broken down in both biotypes and the extractable14C was the same. Uptake, translocation, and metabolic degradation were not involved in the mechanism of resistance of the resistant-Mississippi biotype common cocklebur to MSMA.
Response of a Chlorsulfuron-Resistant Biotype ofKochia scopariato ALS Inhibiting Herbicides and Piperonyl Butoxide
Authors: Kwon Chae Soon , Penner Donald
Published: May 2019

Greenhouse and laboratory studies were conducted to determine kochia resistance to a spectrum of acetolactate synthase (E.C.4.13.18) (ALS)-inhibiting herbicides. The chlorsulfuron-resistant biotype plants were resistant to six herbicides: triflusulfuron, thifensulfuron, halosulfuron, imazamethabenz, chlorsulfuron, and nicosulfuron. But, the resistant biotypes showed sensitivity similar to the susceptible biotypes to three herbicides: metsulfuron, imazethapyr, and imazaquin. The resistant biotypes were slightly less sensitive to primisulfuron, chlorimuron, and flumetsulam than the sensitive biotypes. The I50values for 50% inhibition of the ALS enzyme indicated that the resistant biotype was 22, 18, and 16 times more resistant to primisulfuron, chlorsulfuron, and thifensulfuron than the susceptible biotype. In contrast, the I50ratios (resistant/susceptible) were 3, 2, and 1 for flumetsulam, nicosulfuron, and imazethapyr, respectively. The altered ALS enzyme system of the resistant biotype showed a differential response for the ALS-inhibiting herbicides. Addition of a mixed function oxidase inhibitor, piperonyl butoxide (PBO) at 2 kg ha−1, to primisulfuron and thifensulfuron increased visual injury and reduced plant height of the chlorsulfuron-sensitive kochia biotype plants. The addition of PBO to primisulfuron enhanced visual injury of the resistant biotype at low rates of primisulfuron.
Seed Viability and Dormancy of 17 Weed Species after 9.7 Years of Burial in Alaska
Authors: Conn Jeffery S. , Deck Richard E.
Published: May 2019

A 50-year study at Fairbanks, AK, was started in 1984 to determine soil seed longevity of 17 weed species. Seed were buried in mesh bags 2 and 15 cm deep and were exhumed 0.7, 1.7, 2.7, 3.7, 4.7, 6.7, and 9.7 yr later. Viability was determined by germination and tetrazolium tests. All common hempnettle and quackgrass seed were dead after 2.7 and 3.7 yr, respectively. Less than 1% of wild oats and foxtail barley seed were viable after 3.7 yr, but > 6.7 yr were required for loss of all viability. By 9.7 yr, < 1% seed viability remained for: bluejoint reedgrass, corn spurry, pineappleweed, prostrate knotweed, and wild buckwheat From 2 to 5% of seed from common chickweed, common lambsquarters, flixweed, Pennsylvania smartweed, rough cinquefoil, marsh yellow-cress and shepherd's-purse were viable, while 62% of American dragonhead seed was still alive. Seed longevity in agricultural fields is not greater under subarctic conditions than under warmer conditions.
The Stability of Weed Seedling Population Models and Parameters in Eastern Nebraska Corn (Zea mays) and Soybean (Glycine max) Fields
Authors: Johnson Gregg A. , Mortensen David A. , Young Linda J. , Martin Alex R.
Published: May 2019

Intensive field surveys were conducted in eastern Nebraska to determine the frequency distribution model and associated parameters of broadleaf and grass weed seedling populations. The negative binomial distribution consistently fit the data over time (1992 to 1993) and space (fields) for both the inter and intrarow broadleaf and grass weed seedling populations. The other distributions tested (Poisson with zeros, Neyman type A, logarithmic with zeros, and Poisson-binomial) did not fit the data as consistently as the negative binomial distribution. Associated with the negative binomial distribution is akparameter.kis a nonspatial aggregation parameter related to the variance at a given mean value. Thekparameter of the negative binomial distribution was consistent across weed density for individual weed species in a given field except for foxtail spp. populations. Stability of thekparameter across field sites was assessed using the likelihood ratio test There was no stable or commonkvalue across field sites and years for all weed species populations. The lack of stability inkacross field sites is of concern, because this parameter is used extensively in the development of parametric sequential sampling procedures. Becausekis not stable across field sites,kmust be estimated at the time of sampling. Understanding the variability in it is critical to the development of parametric sequential sampling strategies and understanding the dynamics of weed species in the field.
The Concept and Application of Early Economic Period Threshold: The Case of DCPA in Onions (Allium Cepa)
Authors: Dunan Claudio M. , Westra Philip , Schweizer Edward E. , Lybecker Donald W. , Moore Frank D.
Published: May 2019

The question of when to control weeds traditionally has been approached with the calculation of critical periods (CP) based on crop yields. The concept of economic critical period (ECP) and early (EEPT) and late (LEFT) economic period thresholds are presented as a comprehensive approach to answer the same question based on economic losses and costs of control. ECP is defined as the period when the benefit of controlling weeds is greater than its cost. EEPT and LEFT are the limits of the ECP and can be used to determine when first and last weed control measures should be performed. Calculation of EEPT accounts for the economic losses due to weed competition that occur between planting and postemergence weed control. In this way it is possible to better evaluate the economic feasibility of using preplant or preemergence control tactics. The EEPT for DCPA application is analyzed in the context of onion production in Colorado. The EEPT for DCPA application was calculated from an empirical regression model that assessed the impact of weed load and time of weed removal on onion yields. The EEPT was affected by control efficacy, weed-free yield, DCPA cost, and onion price. DCPA application was economically advisable in only one of 20 fields analyzed because of the tow DCPA efficacy (60%).
Effect of Rainfall on Glyphosate Plus 2,4-D Performance onEchinochloa crus-galli
Authors: Wicks Gail A. , Hanson Gordon E.
Published: May 2019

Barnyardgrass is a problem in winter wheat fields in the central Great Plains following harvest. Glyphosate plus 2,4-D efficacy on barnyardgrass with or without atrazine was investigated under various watering events at three sites in west central Nebraska. Two experiments were initiated at each site. One experiment dealt with rainfall and the other rainfall plus irrigation. Main plots in stubble fields infested with barnyardgrass were sprayed with glyphosate plus 2,4-D at 0.4 plus 0.7, 0.5 plus 0.8, and 0.6 plus 1.0 kg ae ha−1alone and with 2.2 kg ai ha−1atrazine. Barnyardgrass was under drought stress in unwatered areas in 1991 at two sites, but the 1993 site was waterlogged. Glyphosate plus 2,4-D at 0.6 plus 1.0 kg ha1controlled 62, 99, and 100% of the barnyardgrass at the three sites 30 DAT. Nevertheless, control was reduced to 48, 88, and 35% when atrazine was combined with glyphosate plus 2,4-D. Poorest control came when plants were under stress from drought or waterlogging and atrazine was included in the spray solution. In subplots barnyardgrass plants in a 0.8 m2area were watered 6, 3, or 1 d before spraying and 1, 4, 7, or 11 d after spraying. By watering drought-stressed barnyardgrass 6 d before spraying, control generally was similar or better than with later watering dates. Watering 6 d before spraying with glyphosate plus 2,4-D plus atrazine at 0.6 plus 1.0 plus 2.2 kg ha−1reduced but did not eliminate antagonism from atrazine.
Effects of Temperature and Water Potential on Germination of Horehound (Marrubium vulgare) Seeds from two Australian Localities
Authors: Lippai Attila , Smith Paula A. , Price Terence V. , Weiss John , Lloyd Christopher J.
Published: May 2019

Horehound seed from Wyperfeld (Wyp90 and Wyp93) had optimum germination (98%) at constant 25 C and alternating 30/15 C at 0 MPa, while seed from Swift's Creek (SC93) had optimum germination at constant 25 to 27 C (84%) or alternating 25/15 C (95%). The Generalized Additive Models showed the effects of the three covariates (temperature, temperature difference and water potential) followed a smooth and regular pattern. Germination of SC93, Wyp90 and Wyp93 seed increased (P < 0.001) by 9.1, 6.1, and 11.6% for each degree increase in temperature difference but decreased (P < 0.001) with decreases in water potential by a factor of 4.1, 4.8, and 7.1 respectively, and ceased at −1.5 MPa. At constant temperatures the odds of germination were 27, 19, and 18% smaller for water potentials of 0, −0.25 and −0.5 MPa than when alternating temperatures varied by 15 C.
An Outbreak of Cutaneous Aspergillosis in a Tertiary-Care Hospital
Authors: Bryce E.A. , Walker M. , Scharf S. , Lim A.T. , Walsh A. , Sharp N. , Smith J.A.
Published: May 2019

A cluster of four cases of surgical and burn wound aspergillosis occurred in a 900-bed, adult, tertiary-care hospital. The source was traced to the outside packages of dressing supplies, which had become contaminated during construction in the central Inventory Control area. This resulted in patients with large exposed surface areas being inoculated directly with Aspergillus spores.
Blood and Body Fluid Exposures Among Surgeons: A Survey of Attitudes and Perceptions Five Years Following Universal Precautions
Authors: Manian Farrin A.
Published: May 2019

A mail survey of surgeons at our medical center 5 years following adoption of Universal Precautions revealed that 29% estimated having ≥1 potentially serious blood or body fluid exposures (BBEs) per month. Failure to report BBEs (usually needlesticks) to the employee health department was common, and the majority of surgeons in practice for ≥10 years never reported such exposures. The most commonly cited reason for not reporting BBEs was perceived low risk of acquiring bloodborne infections.
Trump’s foreign policy and NATO: Exit and voice
Authors: Sperling James , Webber Mark
Published: May 2019

Donald Trump assumed office in January 2017, committed to revamping US foreign policy and putting ‘America First’. The clear implication was that long-held international commitments would be sidelined where, in Trump’s view, the American interest was not being served. NATO, in the crosshairs of this approach, has managed to ride out much of the criticism Trump has levelled against it. Written off as ‘obsolete’ by the American president, it has fared better in the Trump era than many commentators had predicted. NATO exemplifies a tendency in US foreign policy, which pre-dates Trump, where open criticism stops short of abandonment. This pattern has continued since 2017 and indicates a preference for voice over exit. As such, it suggests that Trump’s foreign policy is not always as illogical as many have assumed. Logic is borne of institutional context: Trump has chosen to articulate voice where institutionalisation makes exit unviable. Institutional resilience in general and NATO’s case specifically has a wider relevance, both for transatlantic relations and international order.
The Dutch Version of the Centrality of Event Scale (CES)
Authors: Vermeulen Mirjam , Smits Dirk , Boelen Paul A. , Claes Laurence , Raes Filip , Krans Julie
Published: May 2019

Abstract. Event centrality is defined as the extent to which the memory of a traumatic event forms a reference point for personal identity and the attribution of meaning to other experiences in a person’s life. The current study investigated the psychometric properties of the Dutch translation of the Centrality of Event Scale (CES; Berntsen & Rubin, 2006 ) and its relation with symptoms of Posttraumatic Stress Disorder (PTSD), depression, exposure to traumatic events as defined by DSM-5 trauma criterion A, and negative life events in a student sample ( N = 967). An underlying structure of one factor was found. This factor structure was replicated in two additional independent samples. High internal consistency was found for a 6-item CES. CES scores were positively related to symptoms of PTSD and depression, to the DSM-5 trauma criterion A, and the number of negative life events. The CES made a unique contribution to the explained variance in PTSD symptoms when controlling for depression. However, CES scores were unrelated to depression when controlling for PTSD symptoms, suggesting that event centrality might be more typically related to PTSD, and less to depression.
Vegetation Functional Properties Determine Uncertainty of Simulated Ecosystem Productivity: A Traceability Analysis in the East Asian Monsoon Region
Authors: Cui Erqian , Huang Kun , Arain Muhammad Altaf , Fisher Joshua B. , Huntzinger Deborah N. , Ito Akihiko , Luo Yiqi , Jain Atul K. , Mao Jiafu , Michalak Anna M. , Niu Shuli , Parazoo Nicholas C. , Peng Changhui , Peng Shushi , Poulter Benjamin , Ricciuto Daniel M. , Schaefer Kevin M. , Schwalm Christopher R. , Shi Xiaoying , Tian Hanqin , Wang Weile , Wang Jinsong , Wei Yaxing , Yan Enrong , Yan Liming , Zeng Ning , Zhu Qiuan , Xia Jianyang
Published: May 2019

Global and regional projections of climate change by Earth system models are limited by their uncertain estimates of terrestrial ecosystem productivity. At the middle to low latitudes, the East Asian monsoon region has higher productivity than forests in Europe‐Africa and North America, but its estimate by current generation of terrestrial biosphere models (TBMs) has seldom been systematically evaluated. Here, we developed a traceability framework to evaluate the simulated gross primary productivity (GPP) by 15 TBMs in the East Asian monsoon region. The framework links GPP to net primary productivity, biomass, leaf area and back to GPP via incorporating multiple vegetation functional properties of carbon‐use efficiency (CUE), vegetation C turnover time (τveg), leaf C fraction (Fleaf), specific leaf area (SLA), and leaf area index (LAI)‐level photosynthesis (PLAI), respectively. We then applied a relative importance algorithm to attribute intermodel variation at each node. The results showed that large intermodel variation in GPP over 1901–2010 were mainly propagated from their different representation of vegetation functional properties. For example, SLA explained 77% of the intermodel difference in leaf area, which contributed 90% to the simulated GPP differences. In addition, the models simulated higher CUE (18.1 ± 21.3%), τveg (18.2 ± 26.9%), and SLA (27.4±36.5%) than observations, leading to the overestimation of simulated GPP across the East Asian monsoon region. These results suggest the large uncertainty of current TBMs in simulating GPP is largely propagated from their poor representation of the vegetation functional properties and call for a better understanding of the covariations between plant functional properties in terrestrial ecosystems.
Properties of the Stimulated Electromagnetic Emissions During the Inclined High‐Frequency Pumping of the Ionosphere Near the Fourth Electron Gyroharmonic at the High‐Frequency Active Auroral Research Program Facility
Authors: Shindin A. V. , Grach S. M. , Sergeev E. N. , Smolina V. P. , Pogorelko N. A. , Bernhardt P. A. , Briczinski S. J. , Broughton M. , LaBelle J. , McCarrick M. J.
Published: May 2019

Many phenomena in the high‐frequency pumped ionosphere exhibit dependence on the pump beam incident angle α. This motivates a systematic study of the α dependence of the stimulated electromagnetic emission (SEE), particularly near electron gyroharmonics. We report the first observations of stationary SEE spectra for α ranging from −28° (north) to 28° (south) at three receiving sites, for the pump frequency (f0) sweeping near the fourth gyroharmonic (4fc). The following is established: (i) For pumping near the magnetic zenith (α = 7°, 14°, 21°), when existent dynamic broad upshifted maximum in the SEE spectrum indicates that artificial ionization layers are excited, suppression of the downshifted maximum at f0 ≈ 4fс is weakest, and 4fс increases. (ii) Weaker similar effects occur for α = −14° (a condition called “mirror magnetic zenith”). (iii) For northern pump beam inclinations, the SEE intensity decreases (in comparison with southern inclinations and vertical), most strongly at the southernmost receiving site.
Controlling hypoxia-inducible factor-2α is critical for maintaining bone homeostasis in mice
Authors: Lee Sun Young , Park Ka Hyon , Yu Hyung-Gu , Kook Eunbyul , Song Won-Hyun , Lee Gyuseok , Koh Jeong-Tae , Shin Hong-In , Choi Je-Yong , Huh Yun Hyun , Ryu Je-Hwang
Published: May 2019

Pathological bone loss is caused by an imbalance between bone formation and resorption. The bone microenvironments are hypoxic, and hypoxia-inducible factor (HIF) is known to play notable roles in bone remodeling. However, the relevant functions of HIF-2α are not well understood. Here, we have shown that HIF-2α deficiency in mice enhances bone mass through its effects on the differentiation of osteoblasts and osteoclasts. In vitro analyses revealed that HIF-2α inhibits osteoblast differentiation by targeting Twist2 and stimulates RANKL-induced osteoclastogenesis via regulation of Traf6. In addition, HIF-2α appears to contribute to the crosstalk between osteoblasts and osteoclasts by directly targeting RANKL in osteoprogenitor cells. Experiments performed with osteoblast- and osteoclast-specific conditional knockout mice supported a role of HIF-2α in this crosstalk. HIF-2α deficiency alleviated ovariectomy-induced bone loss in mice, and specific inhibition of HIF-2α with ZINC04179524 significantly blocked RANKL-mediated osteoclastogenesis. Collectively, our results suggest that HIF-2α functions as a catabolic regulator in bone remodeling, which is critical for the maintenance of bone homeostasis.
Author Correction: Hybridization is a recurrent evolutionary stimulus in wild yeast speciation
Authors: Eberlein Chris , Hénault Mathieu , Fijarczyk Anna , Charron Guillaume , Bouvier Matteo , Kohn Linda M. , Anderson James B. , Landry Christian R.
Published: May 2019

The original version of the Supplementary Information associated with this Article contained errors in Supplementary Figures 2, 12, 20 and 22. The HTML has been updated to include a corrected version of the Supplementary Information; the original incorrect versions of these Figures can be found as Supplementary Information associated with this Correction.
Theoretical analysis of Polycomb-Trithorax systems predicts that poised chromatin is bistable and not bivalent
Authors: Sneppen Kim , Ringrose Leonie
Published: May 2019

Polycomb (PcG) and Trithorax (TrxG) group proteins give stable epigenetic memory of silent and active gene expression states, but also allow poised states in pluripotent cells. Here we systematically address the relationship between poised, active and silent chromatin, by integrating 73 publications on PcG/TrxG biochemistry into a mathematical model comprising 144 nucleosome modification states and 8 enzymatic reactions. Our model predicts that poised chromatin is bistable and not bivalent. Bivalent chromatin, containing opposing active and silent modifications, is present as an unstable background population in all system states, and different subtypes co-occur with active and silent chromatin. In contrast, bistability, in which the system switches frequently between stable active and silent states, occurs under a wide range of conditions at the transition between monostable active and silent system states. By proposing that bistability and not bivalency is associated with poised chromatin, this work has implications for understanding the molecular nature of pluripotency.