bluuebunny/crossref_metadata_2025 huggingface dataset:
Tebuthiuron Formulation and Placement Effects on Response of Woody Plants and Soil Residue
Authors: Meyer Robert E. , Bovey Rodney W.
Published: May 2019

Tebuthiuron {N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimethylurea} in various formulations and placements was applied to honey mesquite (Prosopis glandulosaTorr. # PRCJG), huisache [Acacia farnesiana(L.) Willd. # ACAFA], live oak (Quercus virginianaMill.#QUEVI), Macartney rose (Rosa bracteataJ. C. Wendl. # ROSBC), and Texas whitebrush [Aloysia gratissima(Gillies & Hook.) Troncoso # ALYLY]. There was little difference in a species response to the various tebuthiuron formulations. Pellets (20%) at 2 g ai/tree base reduced the canopy 85% and killed 50% of the honey mesquite. At 1 g ai/plant, two briquettes at 0.5 g ai each or pellets (5.14 g, 20%) killed 37 and 80% of the huisache, respectively. Pellets were no more effective at 2 g than at 1 g ai on huisache. Basal treatments of 0.25, 0.5, 0.5, 1, and 2 g ai tebuthiuron/tree killed from 8 to 22, 48 to 62, 62 to 85, and 92% of the live oak, respectively. Pellets at 2 g ai placed at the base reduced the canopy 83% and killed 59% of the Macartney rose. On Texas whitebrush, 0.25, 0.5, 1, and 2 g ai tebuthiuron/tree killed from 68 to 85, 75 to 100, 90, and 100% of the plants, respectively. Tebuthiuron persisted mainly in the upper 30 cm of soil for at least 15 months.
Germination Stimulants of Witchweed (Striga asiatica) from Hydrophobic Root Exudate of Sorghum (Sorghum bicolor)
Authors: Netzly David H. , Riopel James L. , Ejeta Gebisa , Butler Larry G.
Published: May 2019

Hydrophobic exudate from roots of sorghum [Sorghum bicolor(L.) Moench. #3SORVU ‘IS 8768’] contain fourp-benzoquinones which in the dihydroquinone form are active as germination stimulants of witchweed [Striga asiatica(L.) Kuntz. # STRLU]. The three minorp-benzoquinones were partially characterized and found to be structurally similar to sorgoleone, the majorp-benzoquinone of this exudate. Herbicidal activity of the hydrophobic exudate was due to concentration- and pH-dependent inhibition of root elongation in some but not all weeds tested. Witchweed has apparently adapted these “defense” compounds of sorghum as host-specific germination stimulants.
Accelerated Degradation of Diphenamid in Soils and Means for its Control
Authors: Avidov Elana , Aharonson Nadav , Katan Jaacov
Published: May 2019

Accelerated degradation of the herbicide diphenamid (N,N-dimethyl-α-phenylbenzeneacetamide) was investigated in Israeli soils. Repeated application of this herbicide in the soil in the laboratory enhanced its degradation, which increased with an increasing number of applications. After the fourth application nearly 100% of the herbicide was degraded within 5 days of incubation, whereas only slight degradation was observed during the first 25 days in a previously untreated soil. Accelerated degradation was also observed in a soil collected from a field with previous diphenamid treatments. Fumigation with methyl bromide or treating the soil with the fungicide fentin acetate (triphenyltin acetate) was effective in decreasing the accelerated degradation of diphenamid, whereas the fungicides TMTD (tetramethylthiuram disulfide) and TBZ [2-(4-thiazolyl)benzimidazole] were only partially effective in inhibiting accelerated degradation. In the laboratory, fentin acetate prevented the degradation of diphenamid applied to previously untreated soil. Several fungi capable of degrading diphenamid were isolated from soils with or without accelerated degradation.
Selective Action of the New Herbicide 4-amino-6-(1,1-dimethylethyl)-3-(ethylthio)-1,2,4-triazin-5(4H)-one in Different Wheat,Triticum aestivum, Cultivars
Authors: Fedtke Carl , Schmidt Robert R.
Published: May 2019

14C-labeled 4-amino-6-(1,1-dimethylethyl)-3-(ethylthio)-1,2,4-triazin-5(4H)-one (ethiozin)3was metabolized more rapidly in tolerant than in sensitive wheat,Triticum aestivumL., cultivars. After a 6-h herbicidal pulse, the main metabolites were conjugates at all incubation times up to 48 h. The levels of deaminated and dethioethylated metabolites never exceeded 4% of the extractable radioactivity and also did not differ between tolerant and sensitive plants. On the contrary, 92% of the extractable radioactivity was in conjugates after 24 h in the leaves of tolerant plants compared to 25% in the leaves of sensitive plants. The differently sensitive wheat cultivars conjugated metribuzin, 4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one, at about half the rate that was observed with ethiozin. This finding may explain the fact that most wheat cultivars are more sensitive to metribuzin compared with ethiozin.
Use of Soybean (Glycine max) and Velvetleaf (Abutilon theophrasti) Suspension-Cultured Cells to Study Bentazon Metabolism
Authors: Sterling Tracy M. , Balke Nelson E.
Published: May 2019

Metabolism and phytotoxicity of bentazon by suspension-cultured cells of soybean and velvetleaf were compared. Growth of suspension cells of both species was reduced when the cells were exposed to increasing concentrations of bentazon. However, soybean plants were tolerant and velvetleaf plants were susceptible to postemergence applications of bentazon. After incubation with 1 μM14C-bentazon for 6 h, soybean and velvetleaf cells in the log phase of the culture growth cycle contained similar levels of14C (6 nmol/g fresh weight). Of the total14C in the soybean cells, 57 to 92% was present as the glucosyl conjugates of 6-OH- and 8-OH-bentazon with the remainder present as bentazon; the percentage depended on the phase of the culture growth cycle. Bentazon metabolism was greatest in the stationary phase of growth. Thin, transverse sections of soybean hypocotyl metabolized bentazon to the same two metabolites as soybean suspension cells did. The ratio of 6-O-glucosyl-bentazon to 8-O-glucosyl-bentazon was always greater than 1:1 for both the hypocotyl sections and the suspension cells. Bentazon metabolites were not detected in the velvetleaf cells, the velvetleaf hypocotyl sections, or the media of either species. Soybean suspension-cultured cells appear to be a valid and advantageous system for studying the hydroxylation and glucosylation of bentazon, the primary reactions believed to be responsible for detoxication of the herbicide in tolerant plants.
Patterns of Weed Emergence in Tropical Soil
Authors: Zimdahl Robert L. , Moody Keith , Lubigan Rosario T. , Castin Eduardo M.
Published: May 2019

Patterns of weed emergence in upland and lowland soils were observed for several months after tillage by counting all emerged species. Forty to 50% of weed emergence occurred within 6 weeks of tillage on both sites. Significant emergence occurred within 3 weeks on both sites, but very little emergence occurred within 1 week in lowland soil. The data confirm the strong influence of soil tillage on weed emergence. They also suggest an influence of radiant energy on weed emergence. Peaks of weed emergence 6 or more weeks after tillage often occurred coincident with or soon after peaks of radiant energy.
Influence of Application Time on Clomazone Activity in No-Till Soybeans,Glycine max
Authors: Werling Virginia L. , Buhler Douglas D.
Published: May 2019

Clomazone at 0.7 kg ai/ha or more, applied early preplant, completely controlled weeds before planting of no-till soybeans. Under low weed density (57 plants/m2in untreated control) in 1985, grass weed control was nearly complete and not affected by clomazone application time. Late-season broadleaf weed control was less with preemergence application of clomazone at 1.1 or 1.4 kg/ha than with an early preplant or early preplant-preemergence split application of the same clomazone rate. Addition of metribuzin at 0.2 kg ai/ha overcame this control deficiency. Under greater weed densities (330 plants/m2in untreated control) during 1986 and 1987, early preplant-preemergence split applications gave the greatest control of both grass and broadleaf weeds throughout the growing season. Preemergence application of clomazone failed to completely control common lambsquarters emerged at the time of application. Early preplant applications failed to maintain redroot pigweed control throughout the season. Differences in soybean yield were attributed to differences in weed control. No significant carryover of clomazone residue was detected through greenhouse or field bioassays.
Combinations of Nonselective Herbicides for Difficult to Control Weeds in No-Till Corn,Zea mays, and Soybeans,Glycine max
Authors: Wilson John S. , Worsham A. Douglas
Published: May 2019

The combination of glyphosate and 2,4-D at various rates was evaluated for controlling existing weeds at planting in no-till corn and soybeans. Herbicide combinations in soybeans also included paraquat plus 2,4-D, linuron, or diuron. Standard treatments included glyphosate (0.6 and 1.1 kg ae/ha) and paraquat (0.3 and 0.6 kg ai/ha), and 2,4-D (0.6 kg ae/ha) alone. For corn, the addition of 2,4-D to glyphosate did not improve weed control, although the addition of 2,4-D to paraquat did improve horseweed control. Corn yield with the herbicide combinations was higher than that for the nonselective herbicides alone. Although initial weed control was good in soybeans, weed regrowth in all paraquat alone treatments was substantial, especially with horseweed. The addition of 2,4-D to paraquat improved control of horseweed and tall morningglory. The addition of linuron or diuron to paraquat improved horseweed and common ragweed control, whereas the addition of 2,4-D to glyphosate improved the control of tall morningglory but not the other weed species. Generally, after 4 weeks, all glyphosate treatments provided better horseweed control than all paraquat treatments. Paraquat plus either linuron or diuron and glyphosate alone or in combination with 2,4-D gave the highest soybean yields.
Environmental Modification of Seedling Alfalfa,Medicago sativa, Tolerance to Bromoxynil
Authors: Peregrine Esther K. , Norris Robert F.
Published: May 2019

Seedling alfalfa exhibited increased phytotoxicity from bromoxynil when applications were made with temperatures greater than 28 C both in controlled environments and in the field. Treatments applied in the morning were more phytotoxic than treatments made in the late afternoon. In laboratory experiments, inhibition of oxygen evolution occurred within 1 h after treatment. The amount of permanent damage sustained was dependent on the rate of bromoxynil and the length of time the alfalfa was exposed to light or darkness immediately after spraying. Bromoxynil treatments in cool weather and/or in the late afternoon should minimize injury to the crop.
Effect of Herbicides on Miserotoxin Concentration in Wasatch Milkvetch (Astragalus miservar.oblongifolius)
Authors: Williams M. Coburn , Ralphs Michael H.
Published: May 2019

The effect of herbicides on the concentration of miserotoxin, the toxic compound in Wasatch milkvetch [Astragalus miservar.oblongifolius(Rydb.) Cronq. # ASAMO], was investigated. Eight herbicides or herbicide combinations were applied to Wasatch milkvetch in June 1985 and 1986. The concentration of miserotoxin was determined weekly for 4 weeks after treatments. All treatments in both years significantly reduced the miserotoxin concentration when compared to the controls, except for the 0.6 kg ae/ha rate of clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) in 1986. Wasatch milkvetch treated with triclopyr {[(3,5,6-trichloro-2-pyridinyl)oxy] acetic acid} at 1.7 and 2.2 kg ae/ha desiccated rapidly and had consistently low concentrations of miserotoxin 4 weeks after treatment.
N-Alkylaryltriazine Herbicides: A Possible Link Between Triazines and Phenylureas
Authors: Gardner Gary , Sanborn James R. , Goss John R.
Published: May 2019

A comparison of the structure of the α-methylbenzyl analogue (MBAT) of atrazine with the Photosystem II herbicides atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine] and diuron [N′-(3,4-dichlorophenyl)-N,N-dimethylurea] suggested thatN-alkylbenzyltriazines may be a structural bridge between the triazines and the phenylureas. In the phenylureas, the addition of chlorines at the meta and/or para positions produces a marked increase in activity. Chloro-substituted derivatives of MBAT were synthesized to determine whether this structure-activity relationship also applies to the alkylaryltriazines. Addition of a chlorine to MBAT at the 4-position (CMBAT) caused a substantial increase in intrinsic activity, and a second chlorine at the 3-position (DCMBAT) caused a further increase. In direct comparisons, DCMBAT was more active in vitro than terbuthylazine [6-chloro-N-ethyl-N′-(1,1-dimethylethyl)-1,3,5-triazine-2,4-diamine], the most active chlorotriazine, and was also more active than diruon. The effects of DCMBAT were also measured on triazine-resistant pigweed (Amaranthus hybridusL. # AMACH) both in vivo and in vitro. The activity of this compound in triazine-resistant chloroplasts was intermediate between that of atrazine and diruon both in inhibition of photosynthetic electron transport and in competition for diuron binding sites, with half-maximal values falling in the micromolar range. Whole plant phytotoxicity of DCMBAT on triazine-resistant pigweed was also intermediate between that of diuron and atrazine. Since DCMBAT is a triazine with biological properties similar to that of a urea, we conclude that in a functional as well as structural sense, DCMBAT is a herbicide that is a hybrid between a triazine and a urea.
PARLAMENTO-ARENA O PARLAMENTO DI TRASFORMAZIONE?
Authors: Di Palma Giuseppe
Published: May 2019

Introduzione

Il quesito forse più immediato ed attuale che sorge quando si pensa, oggi, al processo di istituzionalizzazione del Parlamento è se vi siano stati cambiamenti rispetto alla fine degli anni settanta (anni cruciali in tema di istituzionalizzazione), e se questi cambiamenti comportino dei progressi sostanziali nel processo. Cambiamenti ve ne sono stati, come vedremo più avanti. Siccome, però, a parer mio, questi cambiamenti non indicano progressi chiari né permettono estrapolazioni sicure, partirò alla lontana con uno sforzo di riconcettualizzazione — o più modestamente con un tentativo di riformulare in maniera un po’ diversa e magari più convincente analisi già fatte e risapute, ma non sempre condivise.
VLA Observations of Stellar Flares: A 3-Hour Flare of the RS CVN Star λ Andromedae and A 5-Minute Flare of the BP STAR HR 5942
Authors: Drake Stephen A. , Linsky Jeffrey L.
Published: May 2019

We describe high-sensitivity VLA observations of rapidly varying radio emission (‘flares’) from two stars of very different types, one of which (λ And) is a Long-Period RS CVn system, and the other (HR 5942) is a magnetic Bp star. In both cases, however, the physical mechanism producing the radio emission is most likely to be gyrosynchrotron radiation from mildly relativistic, power-law electrons.
Flare Stars Investigations at the Department of Astronomy and the Rozhen National Astronomical Observatory
Authors: Tsvetkov M.K. , Kovachev B.Zh.
Published: May 2019

In the frames of the programme of nonstable star investigations in the Department, of Astronomy and National Astronomical Observatory the investigations of flare stars- stars of spectral type dK - dM whose nonstabi1ity appears first of all through the quick brightness increases take an essential place. The programme of systematic observations was initiated in 1979 with setting into operation of the telescopes of the Rozhen National Observatory.
SMM Observations of the Variability of Active Regions in the UV: Flares, Bursts, and Oscillations
Authors: Drake Stephen A. , Gurman Joseph D. , Orwig Larry E.
Published: May 2019

We have made extensive observations of the time-variability of solar active regions in the far-UV using the ultraviolet spectrometer on SMM. We describe the three different modes of solar variability (impulsive events, bursts and oscillations) that are evident in our data and discuss their physical implications.
Solar Irradiance Variations and their Relation with Solar Flares
Authors: Pap Judit , Vrsnak Bojan
Published: May 2019

A clear association is demonstrated between the dips in the total solar irradiance and flare occurrence. It is found that both the irradiance dips and flares are related to emerging new activity.
Nonlinear Evolution of Parker Instability of Isolated Magnetic Flux Sheet and Its Application to Emerging Magnetic Flux in the Solar Atmosphere
Authors: Shibata K. , Tajima T. , Steinolfson R. , Matsumoto R.
Published: May 2019

A two dimensional MHD code is used to study the nonlinear evolution of the Parker instability in isolated horizontal magnetic flux imbedded in (or below) the solar photosphere. It is found that the magnetic loop expands self-similarly in the nonlinear stage. Numerical results explain many features observed in emerging flux regions.
Return Current Instability in Flares
Authors: Cromwell D. , McQuillan P. , Brown J.C.
Published: May 2019

We consider the problem of ion-acoustic wave generation, and resultant anomalous Joule heating, by a return current driven unstable by a small-area thick-target electron beam in solar flares. We find that, contrary to the usual assumption, the hard X-ray bremsstrahlung emission may actually be enhanced in comparison to conventional thick-target models. This present paper is a summary of the work of Cromwell, McQuillan and Brown (1988).
Exit versus voice – options for socially responsible investment in collective pension plans
Authors: Dietsch Peter
Published: May 2019

What do we owe participants in collective pension plans in terms of socially responsible investment (SRI)? This paper draws into question current conventional wisdom on SRI, which considers investor engagement a more effective strategy than divestment to change morally problematic corporate behaviour. More fundamentally, in light of reasonable disagreement about the objective of SRI, the paper argues that participants in collective pension plans are owed some kind of control over their investments. The final section considers four different institutional arrangements to respect this requirement in practice, ranging from democratic decision procedures to the availability of SRI alternatives.
Broadening the Concept and Measurement of Existence Value
Authors: Loomis John
Published: May 2019

Recent efforts to refine the concept of existence value and to empirically measure it has led to an unnecessary narrowing of the concept of existence value. This paper uses the literature on public goods to argue that existence value is a much broader concept than proposed by several authors. Two commonly used but different empirical approaches to measuring existence values are compared and shown to lead to statistically different decompositions of total value between use and existence categories.
Addicted to compulsion: assessing three core dimensions of addiction across obsessive-compulsive disorder and gambling disorder
Authors: Grassi Giacomo , Makris Nikos , Pallanti Stefano
Published: May 2019

Objective

Several studies suggested that obsessive-compulsive disorder (OCD) patients display increased impulsivity, impaired decision-making, and reward system dysfunction. In a Research Domain Criteria (RDoC) perspective, these findings are prototypical for addiction and have led some authors to view OCD as a behavioral addiction. Thus, the aim of this study was to investigate similarities and differences on impulsivity, decision-making, and reward system, as core dimensions of addiction, across OCD and gambling disorder (GD) patients.

Methods

Forty-four OCD patients, 26 GD patients, and 40 healthy controls (HCs) were included in the study. Impulsivity was assessed through the Barratt Impulsiveness Scale, decision-making through the Iowa Gambling Task, and reward system through a self-report clinical instrument (the Shaps-Hamilton Anhedonia Scale) assessing hedonic tone and through an olfactory test assessing hedonic appraisal to odors.

Results

Both OCD and GD patients showed increased impulsivity when compared to HCs. More specifically, the OCD patients showed cognitive impulsivity, and the GD patients showed both increased cognitive and motor impulsivity. Furthermore, both OCD and GD patients showed impaired decision-making performances when compared to HCs. Finally, GD patients showed increased anhedonia and blunted hedonic response to pleasant odors unrelated to gambling or depression/anxiety symptoms, while OCD patients showed only increased anhedonia levels related to OC and depression/anxiety symptoms.

Conclusion

OCD patients showed several similarities and some differences with GD patients when compared to HCs on impulsivity, decision-making, and reward system, three core dimensions of addiction. These results could have relevant implications for the research of new treatment targets for OCD.
Soothing the heart with music: A feasibility study of a bedside music therapy intervention for critically ill patients in an urban hospital setting
Authors: Fallek Ronit , Corey Kristen , Qamar Aamna , Vernisie Shawna N. , Hoberman Alexander , Selwyn Peter A. , Fausto James A. , Marcus Paula , Kvetan Vladimir , Lounsbury David W.
Published: May 2019

Objectives

Music therapy has been shown to be effective for reducing anxiety and pain in people with a serious illness. Few studies have investigated the feasibility of integrating music therapy into general inpatient care of the seriously ill, including the care of diverse, multiethnic patients. This leaves a deficit in knowledge for intervention planning. This study investigated the feasibility and effectiveness of introducing music therapy for patients on 4 inpatient units in a large urban medical center. Capacitated and incapacitated patients on palliative care, transplantation, medical intensive care, and general medicine units received a single bedside session led by a music therapist.

Methods

A mixed-methods, pre-post design was used to assess clinical indicators and the acceptability and feasibility of the intervention. Multiple regression modeling was used to evaluate the effect of music therapy on anxiety, pain, pulse, and respiratory rate. Process evaluation data and qualitative analysis of observational data recorded by the music therapists were used to assess the feasibility of providing music therapy on the units and patients’ interest, receptivity, and satisfaction.

Results

Music therapy was delivered to 150 patients over a 6-month period. Controlling for gender, age, and session length, regression modeling showed that patients reported reduced anxiety post-session. Music therapy was found to be an accessible and adaptable intervention, with patients expressing high interest, receptivity, and satisfaction.

Significance of Results

This study found it feasible and effective to introduce bedside music therapy for seriously ill patients in a large urban medical center. Lessons learned and recommendations for future investigation are discussed.
Grape hyacinth [Muscari botryoides (L.) Mill] control in a wheat-soybean rotation
Authors: Beam Shawn C. , VanGessel Mark J. , Vollmer Kurt M. , Flessner Michael L.
Published: May 2019

Grape hyacinth is a perennial bulbous species in the Liliaceae. It is commonly grown as an ornamental plant, but it can spread into agricultural fields and become weedy, potentially interfering with harvest and fall-planted crops. There has been limited research on controlling grape hyacinth in cropping systems. Fall and spring applied field-research studies were conducted to determine grape hyacinth control with herbicides labeled for use in wheat or winter fallow before planting soybean. Among fall-applied herbicides, paraquat resulted in the greatest initial grape hyacinth control (90% to 100%). Grape hyacinth control, 16 months after application (MAA), was variable, but the top-performing treatments were glyphosate and metsulfuron plus paraquat, resulting in 65% and 50% control, respectively. After spring applications, grape hyacinth control in November (7 MAA) was variable, but top-performing treatments were glyphosate and metsulfuron, which resulted in at least 26% control. Spring-applied paraquat, carfentrazone, metsulfuron, and sulfosulfuron resulted in 73%, 68%, 69%, and 60% reductions in grape hyacinth bulb counts, compared with the nontreated control 7 MAA, and were the top-performing treatments. Despite product-label prohibitions on rotation to soybeans, no soybean yield reductions were observed from any treatment in either study. Single applications of certain herbicides in the fall or spring can result in good control (>80%) of grape hyacinth initially, but long-term control is poor, and additional research is required.
Bread and Circuses: Sports and Public Opinion in China
Authors: Chen Dan , MacDonald Andrew W.
Published: May 2019

Sports victory constitutes an important part of propaganda in authoritarian states. The heavy state investment in sports industries and sports culture in China illustrates the political importance of sports. However, few studies have systematically examined the exact impact of sports propaganda on public opinion. Using a survey experiment conducted in two Chinese cities, this article finds that broadcast highlighting national sports achievements has significant positive effects on general satisfaction and compliance with the local governments. These results expand on the small, but growing, literature on the effects of sports on political opinions and help detail the specific ways in which sports can affect political attitudes.
Investigation of Forbush Decreases and Other Solar/Geophysical Agents Associated With Lightning Over the U.S. Latitude Band and the Continental Africa
Authors: Okike O.
Published: May 2019

Regardless of the numerous significant contributions in the field (e.g., Svensmark, H. & Svensmark, J., 2009, https://doi.org/10.1029/2009GL038429; Svensmark, J., et al, 2012, https://doi.org/10.5194/acpd-12-3595-2012), the impact of cosmic rays on Earth's weather is still a source of misunderstanding among scientists. Chree method of analysis (Chree, 1912, https://doi.org/10.1098/rsta.1913.0003) is one of the commonest tool used in the investigation. But the method has been queried by some publications. Greater number of these critiques (Forbush et al., 1983, https://doi.org/10.1007/BF00145551; Prager & hoenig, 1989, https://doi.org/10.1577/1548-8659(1989)118<0608:SEAART>2.3.CO;2) (Forbush et al., 1983; Prager & Hoenig, 1989) point to the test of significance of epoch superposition results. Forbush events are the most widely key event time used in solar Earth's weather investigation. Despite the early indications of Marcz (1997, https://doi.org/10.1016/S1364-6826(96)00076-4) that the result of compositing analysis depends on the Forbush event selection criteria and timing, various conflicting methods of event selection still dominate articles documenting Forbush decrease (FD)‐related correlations. The present submission calls the attention of researchers to the need for a systematic FD event identification with respect to timing and magnitude estimation prior to compositing/correlation/regression analyses. The relationship between program‐selected FDs, World Wide Lightning Location Network (WWLLN) data, and solar/geophysical parameters is tested at different regions of the world. Significant correlations between WWLLN and other parameters were observed at the U.S. latitude band and within the African region.
Investigating Microtopographic and Soil Controls on a Mountainous Meadow Plant Community Using High‐Resolution Remote Sensing and Surface Geophysical Data
Authors: Falco Nicola , Wainwright Haruko , Dafflon Baptiste , Léger Emmanuel , Peterson John , Steltzer Heidi , Wilmer Chelsea , Rowland Joel C. , Williams Kenneth H. , Hubbard Susan S.
Published: May 2019

This study aims to investigate the microtopographic controls that dictate the heterogeneity of plant communities in a mountainous floodplain‐hillslope system, using remote sensing and surface geophysical techniques. Working within a lower montane floodplain‐hillslope study site (750 m × 750 m) in the Upper Colorado River Basin, we developed a new data fusion framework, based on machine learning and feature engineering, that exploits remote sensing optical and light detection and ranging (LiDAR) data to estimate the distribution of key plant meadow communities at submeter resolution. We collected surface electrical resistivity tomography data to explore the variability in soil properties along a floodplain‐hillslope transect at 0.50‐m resolution and extracted LiDAR‐derived metrics to model the rapid change in microtopography. We then investigated the covariability among the estimated plant community distributions, soil information, and topographic metrics. Results show that our framework estimated the distribution of nine plant communities with higher accuracy (87% versus 80% overall; 85% versus 60% for shrubs) compared to conventional classification approaches. Analysis of the covariabilities reveals a strong correlation between plant community distribution, soil electric conductivity, and slope, indicating that soil moisture is a primary control on heterogeneous spatial distribution. At the same time, microtopography plays an important role in creating particular ecosystem niches for some of the communities. Such relationships could be exploited to provide information about the spatial variability of soil properties. This highly transferable framework can be employed within long‐term monitoring to capture community‐specific physiological responses to perturbations, offering the possibility of bridging local plot‐scale observations with large landscape monitoring.
From Nano to Micro: Evolution of Magnetic Domain Structures in Multidomain Magnetite
Authors: Nagy Lesleis , Williams Wyn , Tauxe Lisa , Muxworthy Adrian R.
Published: May 2019

Reliability of magnetic recordings of the ancient magnetic field is strongly dependent on the magnetic mineralogy of natural samples. Theoretical estimates of long‐term stability of remanence were restricted to single‐domain (SD) states, but micromagnetic models have recently demonstrated that the so‐called single‐vortex (SV) domain structure can have even higher stability that SD grains. In larger grains (
10 μm in magnetite) the multidomain (MD) state dominates, so that large uniform magnetic domains are separated by narrow domain walls. In this paper we use a parallelized micromagnetic finite element model to provide resolutions of many millions of elements allowing us, for the first time, to examine the evolution of magnetic structure from a uniform state, through the SV state up to the development of the domain walls indicative of MD states. For a cuboctahedral grain of magnetite, we identify clear domain walls in grains as small as ∼3 μm with domain wall widths equal to that expected in large MD grains; we therefore put the SV to MD transition at ∼3 μm for magnetite and expect well‐defined, and stable, SV structures to be present until at least ∼1 μm when reducing the grain size. Reducing the size further shows critical dependence on the history of domain structures, particularly with SV states that transition through a so‐called “unstable zone” leading to the recently observed hard‐aligned SV states that proceed to unwind to SD yet remain hard aligned.
The Equatorial Undercurrent and the Oxygen Minimum Zone in the Pacific
Authors: Busecke Julius J. M. , Resplandy Laure , Dunne John P.
Published: May 2019

Warming‐driven expansion of the oxygen minimum zone (OMZ) in the equatorial Pacific would bring very low oxygen waters closer to the ocean surface and possibly impact global carbon/nutrient cycles and local ecosystems. Global coarse Earth System Models (ESMs) show, however, disparate trends that poorly constrain these future changes in the upper OMZ. Using an ESM with a high‐resolution ocean (1/10°), we show that a realistic representation of the Equatorial Undercurrent (EUC) dynamics is crucial to represent the upper OMZ structure and its temporal variability. We demonstrate that coarser ESMs commonly misrepresent the EUC, leading to an unrealistic “tilt” of the OMZ (e.g., shallowing toward the east) and an exaggerated sensitivity to EUC changes overwhelming other important processes like diffusion and biology. This shortcoming compromises the ability to reproduce the OMZ variability and could explain the disparate trends in ESMs projections.
A Spring Barrier for Regional Predictions of Summer Arctic Sea Ice
Authors: Bonan D. B. , Bushuk M. , Winton M.
Published: May 2019

Seasonal forecast systems can skillfully predict summer Arctic sea ice up to 4 months in advance. For some regions, however, there is a springtime predictability barrier that causes forecasts initialized prior to May to be less skillful. Since this barrier has only been documented in a few general circulation models (GCMs), we evaluate GCMs participating in phase 5 of the Coupled Model Intercomparison Project. We first show sea ice volume skillfully predicts summer sea ice area (SIA) and has similar skill to a perfect model experiment. Given this result, we assess regional SIA predictability across each GCM and find a universal predictability barrier in late spring. For SIA at each summer target month in the marginal seas of the Arctic basin, a notable drop in prediction skill occurs from June to May in each GCM. This suggests summer sea ice forecasts initialized after 1 June will have substantially better prediction skill than forecasts initialized before.
Algal Export in the Arctic Ocean in Times of Global Warming
Authors: Lalande Catherine , Nöthig Eva‐Maria , Fortier Louis
Published: May 2019

Satellite‐derived data suggest an increase in annual primary production following the loss of summer sea ice in the Arctic Ocean. The scarcity of field data to corroborate this enhanced algal production incited a collaborative project combining six annual cycles of sequential sediment trap measurements obtained over a 17‐year period in the Eurasian Arctic Ocean. Here we present microalgal fluxes measured at ~200 m to reflect the bulk of algal carbon production. Ice algae contributed to a large proportion of the microalgal carbon export before complete ice melt and possible detection of their production by satellites. In the northern Laptev Sea, annual microalgal carbon fluxes were lower during the 2007 minimum ice extent than in 2006. In 2012, early snowmelt led to early microalgal carbon flux in the Nansen Basin. Hence, a change in the timing of snowmelt and ice algae release may affect productivity and export over the Arctic basins.
Event Studies of O+Density Variability Within Quiet‐Time Plasma Sheet
Authors: Wang Chih‐Ping , Fuselier Stephen A. , Hairston Marc , Zhang Xiao‐jia , Zou Shasha , Avanov Levon A. , Strangeway Robert J. , Ahmadi Narges , Bortnik Jacob
Published: May 2019

To understand the variations of the O+ ions in the quiet‐time plasma sheet between the regions of cold‐dense plasma sheet (CDPS) and hot plasma sheet (HPS), we conduct three event studies. These studies investigate the O+ densities in the two regions and how they are correlated with the strength of two magnetospheric sources important to ion outflows: the soft electron flux and Poynting flux toward the ionosphere. The CDPS is characterized by two‐component ions (one hot component mixed with one cold component), while the HPS ions consist of only one single hot component. Comparing the O+ density between the CDPS and HPS of the same event, the average CDPS O+ density was higher by a factor of ~2–5. Compared to the HPS, the soft electron flux source within the CDPS was higher, consistent with the fact that the soft electron precipitation and O+ upward number fluxes observed in the ionosphere were also higher within the CDPS. In the plasma sheet, broadband ultralow‐frequency electric and magnetic field waves with the characteristics of kinetic Alfvén waves were often more intense within the CDPS, providing a stronger Poynting flux source. In addition, electron resonant interaction with kinetic Alfvén waves results in acceleration along the magnetic fields and, thus, may drive the observed soft electron precipitation. These correlations suggest that the higher soft electron precipitation and Poynting flux coming from the magnetospheric CDPS likely produce larger ionospheric O+ outflows back to the magnetosphere, thus resulting in the higher O+ density within the CDPS.
Impact of Significant Time‐Integrated Geomagnetic Activity on 2‐MeV Electron Flux
Authors: Mourenas D. , Artemyev A. V. , Zhang X.‐J.
Published: May 2019

We explore the impact on the outer radiation belt of significant time‐integrated ap events of continuously elevated geomagnetic activity, making use of Van Allen Probes measurements in 2013–2017. We show that most high peaks of 1.8‐MeV electron flux occur during the 10 days immediately following such events, with stronger events leading to higher flux. Events larger than 800 nT·hr are always followed by a high peak of flux in the heart of the outer radiation belt. They lead to 10‐day‐averaged 1.8‐MeV electron fluxes of the order of 106 e/cm2/sr/s/MeV in this region and 8×104 e/cm2/sr/s/MeV near geostationary orbit. Accordingly, they can be considered as reliable precursors of high peaks of 2‐MeV electron flux throughout the outer belt. We demonstrate that the flux peaks following such significant events can be parameterized by different geomagnetic indices at different radial locations in 2013–2017. Comparisons between the corresponding modeled flux peaks and observations show a reasonable agreement for both the timing, duration, and level of the peaks with 2015 data from the Van Allen Probes and also with 2002–2012 data from Global Positioning System satellites and 2003–2016 data from Geostationary Operational Environmental Satellites, provided that dropouts are taken into account via an appropriate threshold on solar wind dynamic pressure.
Discovery of processive catalysis by an exo-hydrolase with a pocket-shaped active site
Authors: Streltsov Victor A. , Luang Sukanya , Peisley Alys , Varghese Joseph N. , Ketudat Cairns James R. , Fort Sebastien , Hijnen Marcel , Tvaroška Igor , Ardá Ana , Jiménez-Barbero Jesús , Alfonso-Prieto Mercedes , Rovira Carme , Mendoza Fernanda , Tiessler-Sala Laura , Sánchez-Aparicio José-Emilio , Rodríguez-Guerra Jaime , Lluch José M. , Maréchal Jean-Didier , Masgrau Laura , Hrmova Maria
Published: May 2019

Substrates associate and products dissociate from enzyme catalytic sites rapidly, which hampers investigations of their trajectories. The high-resolution structure of the native Hordeum exo-hydrolase HvExoI isolated from seedlings reveals that non-covalently trapped glucose forms a stable enzyme-product complex. Here, we report that the alkyl β-d-glucoside and methyl 6-thio-β-gentiobioside substrate analogues perfused in crystalline HvExoI bind across the catalytic site after they displace glucose, while methyl 2-thio-β-sophoroside attaches nearby. Structural analyses and multi-scale molecular modelling of nanoscale reactant movements in HvExoI reveal that upon productive binding of incoming substrates, the glucose product modifies its binding patterns and evokes the formation of a transient lateral cavity, which serves as a conduit for glucose departure to allow for the next catalytic round. This path enables substrate-product assisted processive catalysis through multiple hydrolytic events without HvExoI losing contact with oligo- or polymeric substrates. We anticipate that such enzyme plasticity could be prevalent among exo-hydrolases.
Phase evolution of conversion-type electrode for lithium ion batteries
Authors: Li Jing , Hwang Sooyeon , Guo Fangming , Li Shuang , Chen Zhongwei , Kou Ronghui , Sun Ke , Sun Cheng-Jun , Gan Hong , Yu Aiping , Stach Eric A. , Zhou Hua , Su Dong
Published: May 2019

Batteries with conversion-type electrodes exhibit higher energy storage density but suffer much severer capacity fading than those with the intercalation-type electrodes. The capacity fading has been considered as the result of contact failure between the active material and the current collector, or the breakdown of solid electrolyte interphase layer. Here, using a combination of synchrotron X-ray absorption spectroscopy and in situ transmission electron microscopy, we investigate the capacity fading issue of conversion-type materials by studying phase evolution of iron oxide composited structure during later-stage cycles, which is found completely different from its initial lithiation. The accumulative internal passivation phase and the surface layer over cycling enforce a rate−limiting diffusion barrier for the electron transport, which is responsible for the capacity degradation and poor rate capability. This work directly links the performance with the microscopic phase evolution in cycled electrode materials and provides insights into designing conversion-type electrode materials for applications.
Colloidal gel elasticity arises from the packing of locally glassy clusters
Authors: Whitaker Kathryn A. , Varga Zsigmond , Hsiao Lilian C. , Solomon Michael J. , Swan James W. , Furst Eric M.
Published: May 2019

Colloidal gels formed by arrested phase separation are found widely in agriculture, biotechnology, and advanced manufacturing; yet, the emergence of elasticity and the nature of the arrested state in these abundant materials remains unresolved. Here, the quantitative agreement between integrated experimental, computational, and graph theoretic approaches are used to understand the arrested state and the origins of the gel elastic response. The micro-structural source of elasticity is identified by the l-balanced graph partition of the gels into minimally interconnected clusters that act as rigid, load bearing units. The number density of cluster-cluster connections grows with increasing attraction, and explains the emergence of elasticity in the network through the classic Cauchy-Born theory. Clusters are amorphous and iso-static. The internal cluster concentration maps onto the known attractive glass line of sticky colloids at low attraction strengths and extends it to higher strengths and lower particle volume fractions.
Inactivation of nuclear histone deacetylases by EP300 disrupts the MiCEE complex in idiopathic pulmonary fibrosis
Authors: Rubio Karla , Singh Indrabahadur , Dobersch Stephanie , Sarvari Pouya , Günther Stefan , Cordero Julio , Mehta Aditi , Wujak Lukasz , Cabrera-Fuentes Hector , Chao Cho-Ming , Braubach Peter , Bellusci Saverio , Seeger Werner , Günther Andreas , Preissner Klaus T. , Wygrecka Malgorzata , Savai Rajkumar , Papy-Garcia Dulce , Dobreva Gergana , Heikenwalder Mathias , Savai-Pullamsetti Soni , Braun Thomas , Barreto Guillermo
Published: May 2019

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and highly lethal lung disease with unknown etiology and poor prognosis. IPF patients die within 2 years after diagnosis mostly due to respiratory failure. Current treatments against IPF aim to ameliorate patient symptoms and to delay disease progression. Unfortunately, therapies targeting the causes of or reverting IPF have not yet been developed. Here we show that reduced levels of miRNA lethal 7d (MIRLET7D) in IPF compromise epigenetic gene silencing mediated by the ribonucleoprotein complex MiCEE. In addition, we find that hyperactive EP300 reduces nuclear HDAC activity and interferes with MiCEE function in IPF. Remarkably, EP300 inhibition reduces fibrotic hallmarks of in vitro (patient-derived primary fibroblast), in vivo (bleomycin mouse model), and ex vivo (precision-cut lung slices, PCLS) IPF models. Our work provides the molecular basis for therapies against IPF using EP300 inhibition.
Imaging gigahertz zero-group-velocity Lamb waves
Authors: Xie Qingnan , Mezil Sylvain , Otsuka Paul H. , Tomoda Motonobu , Laurent Jérôme , Matsuda Osamu , Shen Zhonghua , Wright Oliver B.
Published: May 2019

Zero-group-velocity (ZGV) waves have the peculiarity of being stationary, and thus locally confining energy. Although they are particularly useful in evaluation applications, they have not yet been tracked in two dimensions. Here we image gigahertz zero-group-velocity Lamb waves in the time domain by means of an ultrafast optical technique, revealing their stationary nature and their acoustic energy localization. The acoustic field is imaged to micron resolution on a nanoscale bilayer consisting of a silicon-nitride plate coated with a titanium film. Temporal and spatiotemporal Fourier transforms combined with a technique involving the intensity modulation of the optical pump and probe beams gives access to arbitrary acoustic frequencies, allowing ZGV modes to be isolated. The dispersion curves of the bilayer system are extracted together with the quality factor Q and lifetime of the first ZGV mode. Applications include the testing of bonded nanostructures.
Local membrane charge regulates β2 adrenergic receptor coupling to Gi3
Authors: Strohman M. J. , Maeda S. , Hilger D. , Masureel M. , Du Y. , Kobilka B. K.
Published: May 2019

The β2 adrenergic receptor (β2AR) signals through both Gs and Gi in cardiac myocytes, and the Gi pathway counteracts the Gs pathway. However, Gi coupling is much less efficient than Gs coupling in most cell-based and biochemical assays, making it difficult to study β2AR−Gi interactions. Here we investigate the role of phospholipid composition on Gs and Gi coupling. While negatively charged phospholipids are known to enhance agonist affinity and stabilize an active state of the β2AR, we find that they impair coupling to Gi3 and facilitate coupling to Gs. Positively charged Ca2+ and Mg2+, known to interact with the negative charge on phospholipids, facilitates Gi3 coupling. Mutational analysis suggests that Ca2+ coordinates an interaction between phospholipid and the negatively charged EDGE motif on the amino terminal helix of Gi3. Taken together, our observations suggest that local membrane charge modulates the interaction between β2AR and competing G protein subtypes.
Genotype–covariate correlation and interaction disentangled by a whole-genome multivariate reaction norm model
Authors: Ni Guiyan , van der Werf Julius , Zhou Xuan , Hyppönen Elina , Wray Naomi R. , Lee S. Hong
Published: May 2019

The genomics era has brought useful tools to dissect the genetic architecture of complex traits. Here we propose a multivariate reaction norm model (MRNM) to tackle genotype–covariate (G–C) correlation and interaction problems. We apply MRNM to the UK Biobank data in analysis of body mass index using smoking quantity as a covariate, finding a highly significant G–C correlation, but only weak evidence for G–C interaction. In contrast, G–C interaction estimates are inflated in existing methods. It is also notable that there is significant heterogeneity in the estimated residual variances (i.e., variances not attributable to factors in the model) across different covariate levels, i.e., residual–covariate (R–C) interaction. We also show that the residual variances estimated by standard additive models can be inflated in the presence of G–C and/or R–C interactions. We conclude that it is essential to correctly account for both interaction and correlation in complex trait analyses.