bluuebunny/crossref_metadata_2025 huggingface dataset:
Johnsongrass Control in Soybeans by Trifluralin and Nitralin
Authors: McWhorter C. G.
Published: May 2019

Field experiments were conducted to study the feasibility of using trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) and nitralin [4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline] for the selective control of johnsongrass [Sorghum halepense(L.) Pers.] from rhizomes and seed in soybeans[Glycine max(L.) Merr. ‘Lee’]. Both herbicides were incorporated into the soil at 0.56 to 3.36 kg/ha with two disk cultivations immediately after application. Most effective johnsongrass control on Dundee silty clay loam (sicl) followed treatments of nitralin or trifluralin at 1.68 to 3.36 kg/ha, but 2 years or more of continuous treatment were required for acceptable control. Trifluralin at 1.12 and 2.24 kg/ha on Sharkey clay and at 0.56 to 2.24 kg/ha on Bosket fine sandy loam (fsl) provided better average johnsongrass control over a 2-year period than nitralin at the same rates, but soybean yields after both herbicides at the same rates were equal. Immediate incorporation of trifluralin or nitralin in all three soils at 1.12 to 2.24 kg/ha for 2 successive years effectively controlled johnsongrass from rhizomes without soybean injury and with greatly increased soybean yields.
Germination of Winter Annual Species from a Rangeland Community Treated by Paraquat
Authors: Evans Raymond A. , Young James A. , Kay Burgess L.
Published: May 2019

Three annual plant species — erect plantain (Plantago erectaMorris), common chickweed [Stellaria media(L.) Cyrill.], and silver hairgrass (Aira caryophylleaL.)—are commonly found and may dominate a unique flora on areas sprayed with paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) in cismontane rangelands of California. The basis of this phenomenon is shown to be temperature-related germination requirements, novel seed characteristics, and lack of competition.
Toluidine and Thiocarbamate Toxicity to Johnsongrass Rhizomes
Authors: Burt Gordon W.
Published: May 2019

The toxicity of several toluidine and thiocarbamate herbicides to johnsongrass[Sorghum halepense(L.) Pers.] rhizome tissue was determined by a triphenyl tetrazolium chloride (TTC) assay. Rhizome sections were incubated in herbicide solutions for 24 hr and then in TTC solution for 24 hr. The amount of reduced TTC was a quantitative measure of herbicide toxicity. Concentrations of the different herbicides required to cause 100% tissue injury indicated that the order of decreasing herbicide toxicity was: USB-3584 (N3,N3-diethyl-2,4-dinitro-6-trifluoromethyl-1,3-phenylendiamine); trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine); benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2-6-dinitro-p-toluidine); nitralin [4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline]; San-9789 [4-chloro-5-(methylamino)-2-(α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazione]; and A-820 (Nsec-butyl-4-tert-butyl-2,6-dinitroaniline). In another study CGA-11607 (N-ethyl-N-tetrahydrofurfuryl-4-trifluoromethyl-2,6-dinitroaniline); AN-5647 [N,N-bis(2-chloroethyl)-2,6-dinitro-p-toluidine]; and CGA-10832 (Nn-propyl-N-cyclopropylmethyl-4-trifluoromethyl-2,6-dinitroaniline) were less toxic than trifluralin to johnsongrass rhizomes. Complete tissue injury caused by the thiocarbamates occurred in the same concentration range (10−3to 10−2M) as the toluidine herbicides. At a concentration required for complete kill the toxicity in decreasing order was: EPTC (S-ethyl dipropylthiocarbamate); vernolate (S-propyl dipropylthiocarbamate); butylate (S-ethyl diisobutylthiocarbamate); and pebulate (S-propyl butylethylthiocarbamate). R-25788 (N,N-diallyl-2,2-dichloroacetamide) at 6.7 × 10−5M had no effect on vernolate, EPTC, or pebulate activity; but it increased the toxicity of butylate to johnsongrass rhizome tissue.
Fertility and Management Treatments to Control Broomsedge in Pastures
Authors: Peters E. J. , Lowance S. A.
Published: May 2019

Tall fescue (Festuca arundinacea Schreb. ‘Kentucky 31′) drilled into a pasture infested with broomsedge (Andropogon virginicus L.) and fertilized with N, P, and K, eliminated broomsedge after 4 years. In a second experiment, fertilization with N, P, and K increased the density of Kentucky bluegrass (Poa pratensis L.), and broomsedge was gradually reduced over a 5-year period. Fertilization with P and K caused the density of legumes and grass to increase and broomsedge was nearly eliminated after 5 years. In both experiments the old growth of broomsedge was mowed each winter and cattle were then able to graze the new growth of broomsedge. Grazing may have aided in the elimination of broomsedge.
Response of Purple Nutsedge to Repeated Applications of Glyphosate
Authors: Zandstra Bernard H. , Teo Chris K. H. , Nishimoto Roy K.
Published: May 2019

Purple nutsedge (Cyperus rotundusL.) plants were treated in the greenhouse and field with glyphosate [N-(phosphonomethyl)glycine]. Fresh weight of leaves, sprouts per original tuber, and sprouts per new tuber were reduced by 4 kg/ha glyphosate in the greenhouse. In the field, glyphosate at 2 and 4 kg/ha was compared to several herbicides for nutsedge control in repeated applications over an 8-month period. After several applications, glyphosate reduced the number of plants per unit area. After rotovation (working the soil thoroughly to a depth of 15 cm) and reapplication, glyphosate and MSMA (monosodium methanearsonate) plots had fewer plants and tubers per unit area than controls.
Distribution of Arsenic in Soil Profiles after Repeated Applications of MSMA
Authors: Hiltbold A. E. , Hajek B. F. , Buchanan G. A.
Published: May 2019

Arsenic as MSMA (monosodium methanearsonate) was applied to three soil types over a 6-year period. Percentage recovery of applied arsenic averaged 67, 57, and 39% in Hart-sells fine sandy loam, Decatur silt loam, and Dothan loamy sand soils, respectively. Essentially all of the arsenic recovered in the soils occurred in the plow layer with no evidence of leaching into deeper zones. Batch-equilibrium and soil-column studies in the laboratory indicated that the rate of MSMA movement through the surface horizon would be fastest in Dothan loamy sand and slowest in Decatur silt loam.
Effect of Ethephon on Mesquite and Huisache Stem Anatomy
Authors: Robnett W. E. , Morey P. R.
Published: May 2019

Application of the ethylene-releasing agent ethephon (2-chloroethylphosphonic acid) as a lanolin paste to stems of honey mesquite [Prosopis juliflora(Swartz) DC. var.glandulosa(Torr.) Cockrell] caused the development of abnormal periderm, cortical, and xylem tissues in a localized portion of the stem within 1 cm of the treatment site. Ethephon inhibited secondary wall deposition in xylem parenchyma cells, whereas normal vessel element differentiation was unaffected. Similar changes in xylem formation occur in ethephon-treated huisache [Acacia farnesiana(L.) Willd.]. Ethephon and 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid] applied separately to honey mesquite and huisache stems have similar inhibitory effects on parenchyma cell differentiation but differ markedly in their effects on vessel element formation.
Degradation of Anilide Herbicides by Propham-Adapted Microorganisms
Authors: Mcclure George W.
Published: May 2019

A mixture of microorganisms cultured under nonsterile conditions on propham (isopropyl carbanilate) herbicide as the sole carbon source was tested for its ability to degrade a number of chlorinated and nonchlorinated anilide compounds. In separate tests under pure-culture conditions, species of the microbial mixture reacted individually in a manner similar to the nonsterile whole. The microorganisms grew and respired rapidly on nonchlorinated anilides, but ring chlorination depressed respiration and inhibited growth. Studies on the dimethylphenylureas indicated that the two methyl groups were primarily responsible for the biological stability of these compounds. All other anilides were degraded by hydrolysis of the side chain followed by metabolic degradation of the ring. Appearance of aniline in the medium depended on the relative rates of production by side chain hydrolysis and disappearance by ring degradation. Acylanilides were hydrolyzed more rapidly than carbanilates and chlorinated rings were degraded much more slowly than unchlorinated rings. Chlorination affected rates of ring degradation and microbial respiration in the following order (most rapid to least rapid): 0 > 2,4 > 2,4,5 > 3 > 4 ≥ 3,4. It is proposed that this unexpected degradative sequence might be explained in terms of the degree of microbial toxicity in the system generated by the formation of chloroazobenzenes from chloroaniline intermediates.
Differential Growth of Corn, Soybean, and Seven Dicotyledonous Weed Seedlings
Authors: Frazee R. W. , Stoller E. W.
Published: May 2019

Differences in emergence, height, and leaf number between corn (Zea maysL.), soybean [Glycine max(L.) Merr.] and seven dicotyledonous weed species were measured until plants reached 15 cm in height or for 40 days, whichever occurred first, under several temperature regimes. Corn grew faster than the weeds at all temperatures. Initially soybean grew more rapidly than the weeds, but when they reached 15 cm in height the growth rate of weeds exceeded that of soybean. A positive and highly significant curvilinear relationship between plant height and leaf number was obtained for several temperature regimes for each species. Equations were derived for determining leaf number from plant height for each species.
Effects of Successive Applications of Preemergence Herbicides on Turf
Authors: Turgeon A. J. , Beard J. B. , Martin D. P. , Meggitt W. F.
Published: May 2019

The effects of seven preemergence herbicides on turfgrass quality, clipping yield, root growth, thatch accumulation, and carbohydrate reserves of three turfgrasses were measured. Nearly all herbicides caused some effect on one or more of the turfgrasses at some point during the 8-yr experiment, especially during mid-summer stress periods. The most consistently injurious herbicide was bandane (polychlorodicyclopentadiene) which caused a marked reduction in turfgrass quality, poor rooting, and increased susceptibility to stripe smut (Ustilago striiformis West. Niesel.). Clipping yields were reduced only in red fescue (Festuca rubra L. ‘Pennlawn’) by bensulide [O,O-diisopropyl phosphorodithioate S-ester with N-(20mercaptoethyl)-benzenesulfonamide], siduron [1-(2-methylcyclohexyl)-3-phenylurea], and terbutol (2,6-di-tert-butyl-p-tolyl methylcarbamate). Except for bandane, only siduron and terbutol caused significant reductions in root growth, and only in ‘Kenblue’-type Kentucky bluegrass (Poa pratensis L.). Thatch accumulation was reduced in ‘Merion’ Kentucky bluegrass treated with benefin (N-butyl-N-ethyl-α,α,α,-trifluoro-2,6-dinitro-p-toluidine) in ‘Kenblue’-type Kentucky bluegrass treated with bandane, benefin, bensulide, and terbutol; and in ‘Pennlawn’ red fescue treated with bandane, calcium arsenate, and terbutol. Carbohydrate reserves were not significantly different among treatments.
Competition of Barnyardgrass by Rice Cultivars
Authors: Smith R. J.
Published: May 2019

Competitiveness of three high-yielding, lodging-resistant rice (Oryza sativaL.) cultivars with barnyardgrass [Echinochloa crus-galli(L.) Beauv.] was compared during 3 years at Stuttgart, Arkansas. ‘Starbonnet,’ ‘Nova 66,’ and ‘Bluebelle,’ which matured in 145, 135, and 125 days, respectively, competed with barnyardgrass for periods ranging from 10 days after crop emergence to all season. ‘Starbonnet’ was the most competitive and ‘Bluebelle’ was the least. Barnyardgrass competition for 10 or 20 days did not reduce grain yields of any cultivar. Weed competition for 40 days or longer reduced yields of ‘Nova 66’ and ‘Bluebelle,’ and competition for 60 days or longer lowered yields of ‘Starbonnet.’ As the period for maturity increased, each cultivar competed more effectively with barnyardgrass.
Herbicide Residues and Weed Species Shifts on Modified-Soil Field Plots
Authors: Weber J. B. , Best J. A. , Witt W. W.
Published: May 2019

A Shubata soil was modified by the addition of organic matter or montmorillonite clay. Three annual applications of fluometuron [1,1-dimethyl-3-(α,α,α-trifluro-m-tolyl)urea], prometryne [2,4-bis(isopropylamino)-6-(methylthio)-s-triazine], and trifluralin (α,α,α-trifluro-2,6-dinitro-N,N-dipropyl-p-toluidine) were made and soil samples analyzed at the end of the third year. Less than 0.05 ppm prometryne was found in the subsoils. Prometryne present (by chemical analysis) in the surface soils ranged from 2% (of that originally applied) in the soil without additives to 20% in the soils modified with organic matter and clay. Approximately 12% of the prometryne present in the soil modified with organic matter and 32% of that in the soil modified with clay was detectable by bioassay. Trifluralin concentration (by chemical analysis) ranged from 2% in the soil without additives and soil modified with clay to 11% in the soil modified with organic matter. Approximately 100% of the trifluralin in soil without additives and soil modified with clay was detectable by bioassay while only 15% of that present in soil modified with organic matter was biologically detectable. Fluometuron was presented in the soils in amounts ranging from 0.6 to 1.9% of that applied. Prometryne and fluometuron greatly decreased the large crabgrass [Digitaria sanguinalis(L.) Scop.] population and increased the population of yellow nutsedge (Cyperus esculentusL.) and crowfootgrass [Dactyloctenium aegyptium(L.) Richter]. Trifluralin greatly decreased large crabgrass and crowfootgrass populations, but the plots became completely infested with yellow nutsedge. Horseweed [Conyza canadensis(L.) Cronq.] became the overall dominant species the first year after the field was taken out of production. Yellow nutsedge, bermudagrass [Cynodon dactylon(L.) Pers.], and other grasses were also prevalent.
Today's Challenges in Weed Science
Authors: Harvey W. A.
Published: May 2019

I would start with a text from Bacon's New Atlantis that reads: “Men ought to know that in the theatre of human life it is only for gods and angels to be spectators.” We are at a stage of societal evolution where we must be part of the action. And action there is today – by politicians, by regulatory agencies, by industry, by scientists, by educators, and by the general public. Our basic challenge is to become a meaningful part of the action mechanism. And we are not alone among scientists trying to find our way in a very concerned and a very confused world. Science itself is suspect today.
Effect of pH on Foliar Uptake of 2,4,5-T-1-14C
Authors: Baur J. R. , Bovey R. W. , Riley Imogene
Published: May 2019

Uptake of 2,4,5-T-1-14C [(2,4,5-trichlorophenoxy)-acetic acid] by immersion of honey mesquite [Prosopis juliflora(Swartz) DC var.glandulosa(Torr.) Cockerell] leaflets rapidly diminished as pH was increased from 3.5 to 9.5. Uptake diminished less rapidly as pH increased when 10-μl droplets were applied to leaflets that were kept moist. Uptake was equivalent from solutions of pH 3.5, 5.5, and 7.5; but severely reduced at pH 9.5, when leaflets were droplet treated and let dry. Uptake under dry conditions from pH 7.5 and 9.5 droplets containing 1 M NH4Cl was equivalent to uptake from pH 3.5 and 5.5 droplets lacking NH4Cl. NH4Cl had no enhancing effect on uptake at any pH when leaflets were immersed or droplet-treated and maintained moist. Low concentrations of urea had no enhancing effect on uptake at pH 9.5 by droplet-treated leaflets that were allowed to dry. Urea concentrations above 0.1 M inhibited uptake.
Herbicide, Leaf Type, and Row Spacing Response in Cotton
Authors: Andries J. A. , Douglas A. G. , Cole A. W.
Published: May 2019

Near isogenic strains of okra, super okra and normal leaf cotton (Gossypium hirsutum L.) were grown in rows spaced 25, 50, and 100 cm apart and were sprayed with various combinations of trifluralin (α,α,α,trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) and fluometuron [1,1-dimethyl-3-(α,α,α,-trifluoro-m-tolyl)urea]. Neither row spacing nor leaf type had any effect on early season weed control. Late season control was better with normal and okra leaf types than with the super okra leaf type. Weed control was significantly better with additional postemergence application of herbicides than with only preplant and preemergence applications. Although the cotton varied in opening date with herbicide programs there was no difference in total yield.
Common Cocklebur Competition in Soybeans
Authors: Barrentine W. L.
Published: May 2019

The competitive effects of common cocklebur (Xanthium pensylvanicumWallr.) on soybeans[Glycine max(L.) Merr. ‘Lee 68′] were studied on Dundee silty clay loam soil from 1970 to 1972. Full-season competition by common cocklebur at 3,300, 6,600, 13,000, and 26,000 plants/ha reduced the 2-year average soybean seed yields 10, 28, 43, and 52%, respectively. Competition from common cocklebur at 100,000 plants/ha for 4, 6, 8, 10, 12, and 16 weeks after soybean emergence reduced soybean seed yields 10, 36, 40, 60, 80, and 80%, respectively. A reduction in soybean stand occurred after 12 or more weeks competition, and an increase in soybean plant height occurred after 10 or more weeks competition. When common cockleburs were removed during the first 4 weeks after soybean emergence, no further removal was required to obtain maximum soybean yield. Bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-(4)3H-one 2,2-dioxide] at 1.1 to 2.2 kg/ha applied over-the-top of common cockleburs and soybeans was as effective as hand removal in terminating competition provided common cocklebur plants were not flowering.
Dates of Herbicide Application for Weed Control in Bermudagrass
Authors: Johnson B. J.
Published: May 2019

In field studies, herbicides were applied at various times to different plots during the summer and fall at two locations over a 3-year period to control winter weeds in nonoverseeded bermudagrass [Cynodon dactylon (L.) Pers.] turf. Annual bluegrass (Poa annua L.) control was higher at Griffin for all herbicide applications made in October when compared with herbicide applications made at the same rate in July, August, or September. At Lawrenceville, optimum annual bluegrass control was obtained when bensulide [O,O-diisopropyl phosphorodithioate S-ester with N-(2-mercaptoethyl) benzenesulfonamide] was applied in August, terbutol (2,6-di-tert-butyl-p-tolyl methylcarbamate) applied in either August or September, benefin (N-butyl-N-ethyl-α,α,α-trifluoro −2,6 dinitro-p-toluidine) applied in September, pronamide [3,5-dichloro-N-(1,1-dimethyl-2-propynyl) benzamide] applied in either September or October, and simazine [2-chloro-4,6-bis(ethylamino)-s-triazine] applied in October. DCPA (dimethyl tetrachloroterephthalate) did not control annual bluegrass satisfactorily at either location, regardless of dates of application. The control of several broadleaf weeds was generally higher when herbicides were applied in October at Griffin and when applied in September or October at Lawrenceville when compared with earlier treatments. Bensulide applied in October was the only herbicide that satisfactorily controlled parsley-piert (Alchemilla microcarpa Boissie Reuter).
Rates of Herbicides in Irrigated Cotton
Authors: Arle H. F. , Hamilton K. C.
Published: May 2019

Rates of trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) applied preplanting were combined with rates of diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] applied postemergence in cotton (Gossypium hirsutumL. ‘Deltapine 16’). In another experiment, two levels of these herbicides were applied in three populations of cotton. All herbicide combinations improved weed control, compared to that of cultivated checks. Applications of 0.28, 0.42, and 0.56 kg/ha of trifluralin combined with 0.56 kg/ha of diuron controlled annual weeds and produced the highest cotton yields. Herbicide treatments had more influence than crop spacing on weed control and crop yield. Weed competition on cultivated checks affected boll weight, seed per boll, and fiber fineness.
Soil Persistence of Trifluralin, Benefin, and Nitralin
Authors: Miller J. H. , Keeley P. E. , Carter C. H. , Thullen R. J.
Published: May 2019

Trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), nitralin [4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline], and benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine) were applied at two rates for five consecutive years (1966 through 1970) as soil-incorporated treatments to cotton (Gossypium hirsutumL. ‘Acala SJ-1’) before the preplanting irrigation. Repeated applications did not significantly affect stand or yield of cotton. Soil samples taken to depth of 120 cm showed that herbicide residues were confined to the tilled zone of soil (upper 30 cm), and about 80% of the residue was in the upper 15 cm of soil. The amount of herbicide residue found annually in the upper 15 cm of soil varied with herbicide and with season. Residues 15 months after final application had been reduced markedly, but were still sufficient to injure sensitive crops. Residues at 30 months had been reduced to innocuous amounts.
Prometryn Movement Across and Through the Soil
Authors: Baldwin F. L. , Santelmann P. W. , Davidson J. M.
Published: May 2019

Specially constructed runoff plots were used to study the effect of simulated rainfall intensity, antecedent soil moisture, and subsequent rainfall on prometryn [2,4-bis(isopropylamino)-6-methylthio-s-triazine] movement across and through a field soil with a 1% slope. The first cm (45.4 L) of runoff was collected and subdivided. The initial 3.8 L of runoff water generally contained a higher concentration of prometryn than did a composite from the next 41.6 L. The sediment contained a higher prometryn concentration than did the runoff water. However, due to the greater volume of water lost compared to sediment, over 90% of the prometryn lost was in the water fraction. When prometryn was applied to a dry soil and rainfall simulated, runoff losses of prometryn were 0.5% or less of the total amount initially applied. The first runoff producing simulated rainfall caused the largest prometryn losses, but prometryn could not be detected in the runoff 1 month subsequent to application. Prometryn was never detected at soil depths greater than 5 cm. Prometryn runoff was greater from plots in which the soil was wet at the time of application.
Ammonium Sulfate Enhancement of Picloram Absorption by Detached Leaves
Authors: Wilson Bruce J. , Nishimoto Roy K.
Published: May 2019

Ammonium sulfate increased the magnitude and rate of14C-picloram (4-amino-3,5,6-trichloropicolinic acid) absorption in detached strawberry guava (Psidium cattleianumSabine) leaves. Absorption of14C-picloram with or without ammonium sulfate leveled off at 6 to 12 hr. The magnitude of the ammonium sulfate-induced increase in14C-picloram absorption was not affected by picloram concentration in the range 250 to 2000 ppmw, or by leaf age. The absorption of14C-picloram was increased by 0.1, 0.5, 1.0, and 10% ammonium sulfate; 0.01% had no effect. Increased14C-picloram absorption resulted from adding the ammonium salts of sulfate, nitrate, chloride, or dibasic phosphate, but ammonium sulfate was the only one of six sulfate salts to increase picloram absorption. A pH adjustment of the external solution from 6 to 4 increased picloram absorption, whereas a pH change from 6 to 8 had no effect. Both ammonium dibasic phosphate at a solution pH of 7.7 and ammonium monobasic phosphate at pH 4.6 increased picloram absorption, whereas potassium dibasic phosphate at pH 9.5 had no effect, and potassium monobasic phosphate at pH 4.6 did increase absorption.
Herbicide Dispersal Patterns: II. Mapping Residues Using X-ray Fluorescence
Authors: Hess F. D. , Falk R. H. , Bayer D. E.
Published: May 2019

Distribution patterns of foliar applied herbicides can be studied by x-ray element mapping provided the herbicide contains an atom with an atomic number of 11 (sodium) or greater. The suitability of an herbicide for element mapping increases as the number of similar detectable atoms per molecule increases. Herbicides containing one detectable atom per molecule provide usable element maps at concentrations of 1.12 kg/ha and higher. Inaccurate element maps can result from: (1) Formulation components containing detectable atoms the same as those of the active ingredient. (2) Herbicide volatility during analysis due to reduced pressures and heating. (3) Specimen topography preventing x-ray detection at some locations on the plant surface. (4) Herbicide concentrations that are below the minimum detectable limit. If adequate precautions are followed in the use of x-ray element mapping, a wide range of uses exist in weed science.
Yellow Nutsedge Sprouting and Resprouting Potential
Authors: Thullen R. J. , Keeley P. E.
Published: May 2019

Yellow nutsedge (Cyperus esculentusL.) was studied to determine the relationship between physical character of tubers and sprouting habits. All tuber lots studied, which averaged from 157 to 662 mg per tuber, sprouted and grew well under greenhouse conditions. Longevity (the time between initial planting and death) increased with tuber weight. Weight of the third and fourth sprouts equalled that of the first and second sprouts for heavy tubers, but sprout weight decreased for light tubers. Detaching the plants at 2-week intervals from the tubers which produced them allowed all buds present to sprout. However, when the plants were detached at 4-week intervals, a reduction in the number of sprouts and a decrease in longevity were observed. Allowing plants to grow for 8 weeks before detaching did not cause any further decrease. Number of buds, number of sprouts, number of multiple sprouts, the time interval between first planting and first sprout, and the time interval between successive sprouts did not vary with initial tuber weight. Prolonged refrigerated storage of tubers caused an increased number of multiple sprouts, a decreased initial and subsequent sprouting interval, and a short life.
Separation and Structural Assignment of the Cis and Trans Isomers of S-(2,3-dichloroallyl)diisopropylthiocarbamate (diallate)
Authors: Rummens F. H. A.
Published: May 2019

The two isomers of diallate [S-2,3-dichloroallyl)diisopropylthiocarbamate] can be isolated by preparative scale gas chromatography using a Carbowax 20M liquid phase. on the basis of IR and NMR spectroscopic and other evidence the isomer with the shorter retention time is assigned the trans configuration and that with the longer retention time is assigned the cis configuration.
Herbicides for Control ofLeptochloa panicoidesin Water-Seeded Rice
Authors: Smith R. J.
Published: May 2019

Postemergence herbicide treatments that controlled tighthead sprangletop [Leptochloa panicoides(Presl) Hitchc.] and redstem (Ammannia auriculataWilld.), did not injure water-seeded rice (Oryza sativaL.), and substantially improved grain yields included: (a) a single application of propanil (3′,4′-dichloropropionanilide) at 4.5 kg/ha applied to weeds 8- to 10-cm tall; (b) two sequential treatments of propanil each at 3.4 kg/ha, with the first treatment applied to weeds 2- to 5-cm tall, and a second treatment applied 4 to 8 days later; (c) a tank mixture of propanil at 3.4 kg/ha and 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid] at 0.6 kg/ha, applied to weeds 8- to 10-cm tall; and (d) a tank mixture of propanil and molinate (S-ethyl hexahydro-1H-azepine-1-carbothioate), each at 2.2 kg/ha, applied to weeds 8- to 10-cm tall. Treatments that controlled tighthead sprangletop or redstem unsatisfactorily or inconsistently and did not improve grain yields as much as more effective treatments included: preplant or postemergence treatments of molinate, or preplant treatments of nitrofen (2,4-dichlorophenyl-p-nitrophenyl ether), fluorodifen (p-nitrophenylα,α,α-trifluoro-2-nitro-p-tolyl ether), CNP (2,4,6-trichlorophenyl-p-nitrophenyl ether), or He-314 (p-nitrophenyl-m-tolyl ether).
Purple Nutsedge Control by Bentazon and Perfluidone in Turfgrasses
Authors: Johnson B. J.
Published: May 2019

Field and greenhouse experiments were conducted on bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)one 2,2-dioxide] at 2.2 and 4.4 kg/ha and perfluidone {1,1,1-trifluoro-N-[2-methyl-4-(phenylsulfonyl) phenyl] methanesulfonamide} at 4.5 and 9.0 kg/ha for purple nutsedge (Cyperus rotundusL.) control and tolerance of five turfgrasses. A single application of each herbicide was applied to purple nutsedge, but single and repeated applications were applied to turfgrasses. Purple nutsedge control during the initial year of treatment was 98 to 100% when bentazon was applied in late spring, but the control was only 28 to 68% when applied in mid or late summer. Perfluidone controlled 76 to 87% of purple nutsedge when applied in late spring and 95 to 100% when applied in late summer. Bentazon treatments generally did not cause turf injury. In the field, perfluidone treatments injured St. Augustinegrass [Stenotaphrum secundatum(Walt.) Kuntze], zoysia grass (Zoysia japonica×Z. teniuflolia‘Emerald’), centipedegrass [Erenoehloa ophiuroides(Munro) Hack.], and common bermudagrass [Cynodon dactylon(L.) Pers.]. ‘Tifway’ bermudagrass was generally tolerant to perfluidone treatments. In the greenhouse, perfluidone reduced the root growth of all turfgrasses except centipedegrass when compared with untreated checks.
Activity of Glyphosate on Johnsongrass
Authors: Parochetti J. V. , Wilson H. P. , Burt G. W.
Published: May 2019

Glyphosate [(N-phosphonomethyl) glycine] was evaluated for three years as a foliar herbicide for the control of johnsongrass [Sorghum halepense (L.) Pers.]. In the greenhouse, maximum rhizome kill resulted from foliar applications of glyphosate at 1.12 to 2.24 kg/ha. In several field studies, plowing from 4 to 21 days following glyphosate application had little effect on johnsongrass control; plowing within 0.5 hr following glyphosate application resulted in less control than when plowing was delayed for 12 days. In stage of growth studies, control was better when glyphosate was applied to johnsongrass in the boot to full head stage than earlier when johnsongrass was 45 to 60 cm in height. In ‘York’ soybeans [Glycine max (L.) Merr.], glyphosate at 1.12 to 2.24 kg/ha applied 12 to 14 days prior to plowing and trifluralin (a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) incorporated prior to planting provided good johnsongrass control. In ‘3369A’ corn (Zea mays L.) directed postemergence applications of glyphosate provided good johnsongrass control but caused extensive crop injury.
POTERE, SCAMBIO E CONFLITTO
Authors: Barry Brian
Published: May 2019

Introduzione

≪ Potere ≫ e ≪ conflitto ≫ sono due termini di cui pare non si possa fare a meno, anche se ci si può preoccupare di quel che dicono i puristi metodologici. Siamo propensi a credere che, se potessimo capire la distribuzione del potere e le linee e le quantità di conflitto, avremmo la chiave per la spiegazione degli avvenimenti politici nel mondo intero, in una società specifica o in un gruppo — associazione o organizzazione — facente parte di una società.
OPINIONI POLITICHE DELLE CORRENTI DEMOCRISTIANE IN EMILIA-ROMAGNA
Authors: Leonardi Robert
Published: May 2019

Introduzione

Il problema delle cause e degli effetti del frazionismo nei partiti politici ha sollevato la curiosità e, molte volte, lo stupore sia dei politologi che dei cittadini comuni in molti e diversi sistemi politici. Questo interesse si è rivelato particolarmente elevato tra gli studiosi della politica italiana. Il frazionismo nei maggiori partiti di governo apparentemente è la chiave per comprendere parecchi collegamenti cruciali nel sistema politico italiano fra: 1) l'organizzazione partitica formale descritta negli statuti dei partiti e l'impegno informale quotidiano degli attivisti di partito; 2) la struttura organizzativa del partito in quanto sistema di autorità e il potere gestito dai rappresentanti del partito in parlamento, nei consigli regionali e comunali, ecc.; 3) gli incentivi per l'impegno dei leaders di partito e le motivazioni degli elettori che votano per un partito piuttosto che per un altro; 4) l'ideologia che definisce lo spazio politico occupato da un partito e le realtà che stanno alla base del conseguimento e dell'amministrazione del potere politico, e 5) la necessità di una disciplina di partito e la necessità, al tempo stesso, di un'appropriata autonomia per gli attivisti di partito per lo svolgimento dei loro ruoli politici.
REFERENDUM ABROGATIVO E CLASSE POLITICA
Authors: Armaroli Paolo
Published: May 2019

Introduzione

Il referendum abrogativo ha avuto scarsa fortuna da noi. Ciò era forse prevedibile fin dal momento in cui l'istituto fu inserito nella carta costituzionale. A raccogliere l'eredità degli entusiasmi ultrademocratici del primo dopoguerra, non eravamo rimasti che noi, o quasi, difatti. Oggi, comunque, questa scarsa fortuna dell'istituto È un fatto non contestabile: bastino a riprova questi pochi dati. La legge di attuazione dei referendum e dell'iniziativa popolare delle leggi è intervenuta soltanto nel 1970, a 22 anni, dunque, dall'entrata in vigore della costituzione. A tutt'oggi, a più di 4 anni dalla legge istitutiva, si è svolto un solo referendum, il 12 e 13 maggio di quest'anno; e per di più, dopo ben 3 anni dalla sua richiesta. Le altre iniziative che sono state tentate, sono tutte abortite, essendo stato impossibile raccogliere il mezzo milione di firme necessario per mettere in moto la macchina del referendum.
HIV transmission between spouses living in Lu'an city, Anhui province, China: a longitudinal study
Authors: Ma Gongyan , Chen Haiyan , Chen Jin , Jiang Zhenghao , Ma Tai
Published: May 2019

This study aims to investigate the human immunodeficiency virus (HIV) transmission rate in HIV serodiscordant couples, in addition to the relevant influencing factors. From January 1999 to August 2016, patients with HIV/AIDS (index cases) along with their fixed partners were registered and monitored to determine the rate of HIV transmission between couples, as well as relevant influencing factors. A total of 231 HIV-positive couples were investigated, of these, 45-negative (19.48%) partners were infected with HIV via sexual transmission prior to diagnosis of the first case detected in couples. After diagnosis, the transmission rate between spouses was 0.39 per 100 person-years (2/507.7), and the cumulative transmission rate was 1.08% (2/186), which was significantly lower than the transmission rate before diagnosis (χ2 = 35.714, P < 0.001). Among the 119 HIV/AIDS patients who received antiretroviral therapy (ART), the transmission rate was 0 (0/119), whereas the transmission rate was 2.99% (2/67) in HIV/AIDS patients who did not receive ART. In addition, HIV transmission rate in serodiscordant couples was high prior to diagnosis of the index case. However, following diagnosis, the transmission rate was reduced, and the risk of transmission in the index case with antiviral treatment was null. Therefore, a prompt intervention in HIV discordant couples with ART of index case is vital to reduce the risk of HIV transmission.
Impact evaluation of DC operating condition on DPD linearizability and power efficiency in GaN-based power amplifiers
Authors: Jędrzejewski Konrad , Rosołowski Dawid W. , Wojtasiak Wojciech
Published: May 2019

The paper presents the results of studies on the effect of transistor DC operating conditions on GaN power amplifiers’ (PAs) power efficiency and linearity improved by digital predistortion (DPD). The single-ended 10 W (ISM2.45 GHz) and 150 W (3.4/3.6 GHz) GaN HEMT PAs excited by wideband LTE20 E-TM1.1 signal were tested. To check the applicability of the small-signal approach for designing of LTE signals’ PAs, the 150 W PA using transistor model extracted fromS-parameters measured at the properly selected operating points was designed. The conventional DPD based on the indirect learning architecture and the memory polynomial model of PA non-linearity was implemented. The results of the research show that in case of class A and B PAs operating up to several dozen watts, an additional improvement in adjacent channel leakage ratio (ACLR) of the order of a few dB only by an increase in the quiescent drain current of PA transistor can be achieved. However, a noticeable ACLR improvement with a coincident increase in power-added efficiency (PAE) can be obtained by choosing the compromise DC operating point and using DPD. In the case of high-PAs, the linearity and efficiency are strongly dependent on the load of a transistor, thus the role of DPD is significantly increased.
Sex-Specific Impact of Changes in Job Status on Suicidal Ideation
Authors: Kim Dae-Hwan , Rodríguez Andrés Antonio , Leigh J. Paul
Published: May 2019

Abstract. Background: Around the globe, 800,000 people die from suicide every year. Despite being one of the leading causes of death, suicide remains a low public health priority. Korea has the second highest total suicide rate among Organisation for Economic Co-operation and Development (OECD) countries. Aims: The aim of this study was to explore how changes of job status influence suicidal risk in Korea, which lags behind other OECD countries in job security because temporary and part-time jobs are more prevalent in Korea. Method: We made use of a large longitudinal dataset, the Korea Health Panel (KHP). Results: Our findings revealed that a negative change in employment status increased the risk of suicide, but only for males. Limitations: Some individuals might intentionally change their job status, but the data do not indicate why the job status of an individual changes. Conclusion: These findings provide useful insights regarding the Korean labor market. In particular, tackling the issue of job stability, providing training polices for the unemployed and under-employed, and considering social insurance schemes may help to reduce suicide risk.
Fluid‐Assisted Strain Localization in Quartz at the Brittle/Ductile Transition
Authors: Papeschi Samuele , Musumeci Giovanni
Published: May 2019

A mylonitic quartzite with conjugate and synthetic shear bands was investigated by Electron Backscatter Diffraction and optical microscopy to obtain insights on recrystallization mechanisms and strain localization in quartz at plastic to semibrittle conditions close to the brittle‐ductile transition. The mylonitic quartzite deformed during late Miocene thrusting coeval with contact metamorphism in the high‐strain domains of the Calamita Schists (Elba Island, Italy). Mylonitic deformation occurred from amphibolite to lower greenschist facies conditions during cooling of the aureole. Dynamic recrystallization, dominated by the activity of dislocation creep by prism  slip, produced recrystallized quartz layers mantling relic large quartz porphyroclasts. Under decreasing temperature and fluid‐rich conditions, quartz porphyroclasts acted as relatively rigid bodies and fractured along synthetic and conjugate C′ shear bands. Shear bands developed along kinematically favored orientations, just locally assisted by weak crystallographic planes in quartz. Fracturing along shear bands was assisted by cataclasis and fluid infiltration enhancing fracture propagation and healing by recrystallization and authigenesis of new quartz and phyllosilicate grains. The process enhanced the propagation of and strain localization in shear bands, with the development of bands of weak phyllosilicates. Furthermore, we observed the development of a c axis preferred orientation (CPO) related to dissolution and precipitation of new grains with their c axis oriented parallel to shear bands. This study highlights the importance of the interplay between brittle and crystal‐plastic processes and fluid ingress in the semibrittle regime to understand deformation partitioning and strain localization.
The Statistical Characteristics of Small‐Scale Ionospheric Irregularities Observed in the Martian Ionosphere
Authors: Fowler C. M. , Bonnell J. W. , Huba J. D. , Andersson L. , Espley J. , Benna M. , Ergun R. E.
Published: May 2019

Small‐scale ionospheric irregularities in magnetic field strength and ionospheric density have recently been discovered at Mars by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. Studying these irregularities provides insight into the interaction between the thermosphere and ionosphere and allows for comparative aeronomy between Mars, Earth, and other planets. This paper reports the first statistical study utilizing 3.5 years of MAVEN in situ measurements to characterize these irregularities and to provide maps of where these irregularities are most likely to be observed. Irregularities are most likely to be observed at dawn and dusk, between solar zenith angles of 90° and 150°, although events are observed all the way to midnight. Irregularities occur primarily outside of the crustal magnetic field regions, between altitudes of ∼130 and 160 km, when ionospheric dynamo conditions exist (magnetized electrons and unmagnetized ions). The irregularities appear to be MHD‐like in nature (an interesting difference to their electrostatic terrestrial counterparts), characterized by variations in absolute magnetic field strength of 5–15% of the background field and perpendicular to magnetic field length scales of 5–20 km. Although MAVEN cannot accurately resolve the associated density variations, we estimate these variations to typically be between 10% and 75% of the background ionospheric density. When present, irregularity events appear to occur with equal likelihood above and below the ionospheric peak. At Earth, the occurrence of irregularity events exhibits strong seasonal dependencies; the MAVEN data set is currently too small to identify any conclusive trends as a function of Mars season.
Gravitational Changes of the Earth's Free Oscillation From Earthquakes: Theory and Feasibility Study Using GRACE Inter‐satellite Tracking
Authors: Ghobadi‐Far Khosro , Han Shin‐Chan , Sauber Jeanne , Lemoine Frank , Behzadpour Saniya , Mayer‐Gürr Torsten , Sneeuw Nico , Okal Emile
Published: May 2019

GRACE satellites have detected regional‐scale preseismic, coseismic, and postseismic gravity changes associated with great earthquakes during the GRACE era (2002‐2017). Earthquakes also excite global‐scale transient gravity changes associated with free oscillations that may be discerned for a few days. In this study, we examine such global gravity changes due to Earth's free oscillations and quantify how they affect GRACE measurements. We employ the normal mode formalism to synthesize the global gravity changes after the 2004 Sumatra earthquake and simulate the (gravitational) free oscillation signals manifested in the GRACE K‐band ranging (KBR) measurements. Using the Kaula orbit perturbation theory, we show how GRACE inter‐satellite distances are perturbed through a complex coupling of eigenfrequencies of the normal modes with the Earth's rotation rate and the GRACE satellites' orbital frequency. It is found that a few gravest normal modes can generate range‐rate perturbations as large as 0.2 μm/s, which are comparable to actual errors of GRACE KBR ranging and accelerometer instruments. Wavelet time‐frequency analysis of the GRACE KBR residual data in December 2004 reveals the existence of a significant transient signal after the 2004 Sumatra earthquake. This transient signal is characterized by a frequency of ~0.022 mHz that could be potentially associated with the largest excitation due to the “football” mode of the Earth's free oscillation. However, the results are also affected by low‐frequency noise of the GRACE accelerometers. Improved space‐borne gravitational instrumentation may open new opportunities to study the Earth's interior and earthquakes independently from global seismological analysis.
Atlantic Circulation and Ice Sheet Influences on Upper South Atlantic Temperatures During the Last Deglaciation
Authors: Umling N. E. , Oppo D. W. , Chen P. , Yu J. , Liu Z. , Yan M. , Gebbie G. , Lund D. C. , Pietro K. R. , Jin Z. D. , Huang K.‐F. , Costa K. B. , Toledo F. A. L.
Published: May 2019

Atlantic Meridional Overturning Circulation (AMOC) disruption during the last deglaciation is hypothesized to have caused large subsurface ocean temperature anomalies, but records from key regions are not available to test this hypothesis, and other possible drivers of warming have not been fully considered. Here, we present the first reliable evidence for subsurface warming in the South Atlantic during Heinrich Stadial 1, confirming the link between large‐scale heat redistribution and AMOC. Warming extends across the Bølling‐Allerød despite predicted cooling at this time, thus spanning intervals of both weak and strong AMOC indicating another forcing mechanism that may have been previously overlooked. Transient model simulations and quasi‐conservative water mass tracers suggest that reduced northward upper ocean heat transport was responsible for the early deglacial (Heinrich Stadial 1) accumulation of heat at our shallower (~1,100 m) site. In contrast, the results suggest that warming at our deeper site (~1,900 m) site was dominated by southward advection of North Atlantic middepth heat anomalies. During the Bølling‐Allerød, the demise of ice sheets resulted in oceanographic changes in the North Atlantic that reduced convective heat loss to the atmosphere, causing subsurface warming that overwhelmed the cooling expected from an AMOC reinvigoration. The data and simulations suggest that rising atmospheric CO2 did not contribute significantly to deglacial subsurface warming at our sites.
Integrated data analysis allows the establishment of a new, cosmopolitan genus of marine Macrodasyida (Gastrotricha)
Authors: Todaro M. Antonio , Dal Zotto Matteo , Kånneby Tobias , Hochberg Rick
Published: May 2019

Macrodasyida (phylum Gastrotricha) comprises 365 species distributed across 34 genera and 10 families. However, current classification is under revision due to the contradictory results of molecular and morphological cladistic analyses. Studies aimed at bridging the gaps took advantage of supplementary assessments of poorly known species and particularly from observations of new taxa showing original traits that could help to identify plesiomorphic character states in these anatomically diverse micrometazoa. We follow this path by describing three new interesting macrodasyidan species respectively from Italy, Brazil and Sweden. In many respects, the new species resemble most closely species of the genus Macrodasys; however, details of the external morphology, in combination with the different lay-out of the reproductive system and the tiny spermatozoa lacking a visible flagellum, suggest they belong to a new genus, possibly in the family Macrodasyidae. These hypotheses are supported by the phylogenetic relationships of 47 taxa inferred from analyses of the 18S rRNA gene, which found the new species clustering with Thaidasys tongiorgii in a subset of a larger clade containing Macrodasys. Accordingly, the establishment of the following taxa is proposed: Kryptodasys gen. nov., K. marcocurinii sp. nov., K. carlosrochai sp. nov. and K. ulfjondeliusi sp. nov.