bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancement of Herbicide Activity with an Isoparaffinic Oil Carrier
Authors: Burr R. J. , Warren G. F.
Published: May 2019

Several herbicides were tested in the greenhouse on ivyleaf morningglory (Ipomoea hederacea(L.) Jacq.), green foxtail (Setaria viridis(L.) Beauv.), purple nutsedge (Cyperus rotundusL.), and quackgrass (Agropyron repens(L.) Beauv.) to determine the degree of enhancement in activity that could be obtained with an isoparaffinic oil carrier applied at 140 L/ha. The enhancement varied with the herbicide and with the species, ranging from 16-fold enhancement with 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) and 2-sec-butyl-4,6-dinitrophenol (dinoseb) on ivyleaf morningglory to no enhancement of atrazine activity on purple nutsedge and quackgrass or (2,4-dichlorophenoxy)acetic acid (2,4-D) activity on quackgrass and ivyleaf morningglory. An oil adjuvant was less effective in enhancing dinoseb and 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (linuron) activity than was the isoparaffinic oil carrier. Also, the isoparaffinic oil carrier emulsified in water was less effective than the undiluted oil in enhancing dinoseb activity on green foxtail, even though equal volumes of the isoparaffinic oil were applied.
Effect of Soil Type and Irrigation Method on Lateral Movement of Cycloate
Authors: Stanger Charles E. , Appleby Arnold P.
Published: May 2019

In greenhouse studies, lateral movement and toxicity ofS-ethyl N-ethylthiocyclohexanecarbamate (cycloate) to barnyardgrass (Echinochloa crusgalli(L.) Beauv.) was greater in a loamy sand soil than in two silt loam soils when cycloate was applied by subsurface line injection. Greatest movement and effectiveness resulted from injection into a preirrigated soil without further irrigation. Lateral movement was adequate under furrow irrigation, but the treated band was displaced. Movement of the cycloate was inadequate under sprinkler or subirrigation. Cycloate was more effective when mechanically mixed with the soil than when injected. Cycloate moved more readily in moist soils than in dry soils. When cycloate was injected into a dry loamy sand soil, movement was similar whether irrigation was applied immediately or after 24 hr.
Influence of Four Weeds on Enzyme Components of Cabbage, Tomato, and Lettuce Seedlings
Authors: Retig B. , Holm L. G.
Published: May 2019

Studies were made of isozyme patterns of three enzymes and of total soluble proteins from seedlings of three crop species which were grown in association with different weed species. The gel electrofocusing separation technique was used. Marked qualitative and quantitative changes were observed in peroxidase of cabbage (Brassica oleraceaL.) seedlings when grown in association with jimsonweed (Datura stramoniumL.), velvetleaf (Abutilon theophrastiMedic.), wild mustard (Brassica kaberDC.), and green foxtail (Setaria viridis(L.) Beauv.). No differences were observed when lettuce (Lactuca sativaL.) and tomato (Lycopersicum esculentumMill.) were grown in association with the above weed species. No differences were found in total soluble proteins or the isozyme patterns of esterase and acid phosphatase.
Phenology of Reproduction of Medusahead
Authors: Young James A. , Evans Raymond A. , Kay Burgess L.
Published: May 2019

The phenology of reproduction was highly variable among 23 selections of medusahead(Taeniatherum asperum(Sim.) Nevski). Selections with markedly early and late maturity were observed. The phenology generally was consistent during 4 years of testing at Reno, Nevada, and during 2 years at Davis, California. Individual selections differed greatly in phenology between two locations. Some of the selections exhibited phenotypic plasticity in phenology when grown in competition with other weeds.
Propanil and TCAB Residues in Rice Soils
Authors: Kearney P. C. , Smith R. J. , Plimmer J. R. , Guardia F. S.
Published: May 2019

We surveyed soils that produce rice(Oryza SativaL.) at the University of Arkansas Rice Branch Experiment Station at Stuttgart, Arkansas, to determine whether residues of 3, 3′,4,4′-tetrachloroazobenzene (hereinafter referred to as TCAB) accumulated with repeated applications of 3′,4′-dichloropropionanilide (propanil). We sampled Crowley silt loam with known histories of propanil application to determine the effect of depth, rate, and time on TCAB formation. Propanil and TCAB were measured by electron capture gas chromatography. Low concentrations of TCAB (<0.2 ppm) generally were detected in the surface 0 to 10.1-cm layer of soil receiving applications of propanil at rates of 6.7 kg/ha. Concentration and occurrence of TCAB decreased with increasing time and depth in soil.
Application of Herbicides in Foam
Authors: McWhorter C. G. , Barrentine W. L.
Published: May 2019

We constructed a foam applicator capable of creating 300 to 400 gal of foam from 1 gal of water. The equipment was successful for applying herbicides in cotton (Gossypium hirsutum L., var. Stoneville 213) and soybeans (Glycine max Merr., var. Lee) after emergence. Weed control was equal with applications in foam as compared to conventional applications in water sprays. Foam production was highly dependent on the type and concentration of surfactant used. Various additives increased foam persistence in laboratory studies. However, for maximum effectiveness under field conditions, additives are needed that are more effective in increasing foam persistence than the ones evaluated.
Soil Moisture Effects on Competitive Ability of Weeds
Authors: Wiese Allen F. , Vandiver C. Wendell
Published: May 2019

Ten plant species were grown in competition with each other at different soil moisture levels in a greenhouse. Corn (Zea mays L.), barnyardgrass (Echinochloa crusgalli (L.) Beauv.), cocklebur (Xanthium pensylvanicum Wallr.), sorghum (Sorghum vulgare L., var. RS 626), and large crabgrass (Digitaria sanguinalis (L) Scop.) produced the most growth in wet soil. Dry soil greatly reduced growth of these species. Palmer amaranth (Amaranthus palmeri S. Wats.) produced an intermediate amount of growth under wet and medium soil moisture and much less in dry soil. Kochia (Kochia scoparia (L.) Schrad.), Russian thistle (Salsola kali L., var. tenuifolia Tausch), buffalobur (Solanum rostratum Dunal.), and tumble-grass (Schedonnardus paniculatus (Nutt.) Trel.) produced much less growth under wet conditions than the more competitive species, but growth was not reduced in dry soil. Russian thistle produced twice as much growth in dry as in wet soil.
The Effect of Herbicides on Lateral Roots and Nut Quality of Pecans
Authors: Norton J. A. , Walter J. P. , Storey J. B.
Published: May 2019

Trifluralina,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) applied at 1.12 kg/ha inhibited lateral root development on field-grown pecan(Carya illinoensis(Wang.) K. Koch) seedlings. In a greenhouse study, inhibition of lateral roots, club-shaped radicles, and restricted penetration of tap roots resulted when pecans were planted in soil treated with 1.0 ppm trifluralin. When pecans were planted above soil treated with trifluralin, normal root development occurred only in the soil which had not been treated. Lateral roots were inhibited in the trifluralin-treated soil. Pecan nuts from trifluralin plots were smaller than those collected from controls, but other factors of quality were statistically equal or superior to nuts harvested in plots which had been treated with 2-chloro-4,6-bis-(ethylamino)-s-triazine (simazine) and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron). The smaller nut size was attributed to lateral root inhibition by trifluralin early during nut development.
SOCIOLOGIA E SCIENZA POLITICA IN GAETANO MOSCA
Authors: Lombardo Antonio
Published: May 2019

Introduzione

II problema del potere e delle élites politiche costituisce certamente uno dei nodi piú complessi della sociologia e della scienza politica. Al centro dell'interesse del sociologo e del politologo sono tuttora domande di questo tipo: E inevitabile il formarsi di un'oligarchia al vertice delle organizzazioni di grandi dimensioni? Ci sono differenze specifiche tra le leggi che regolano le tendenze oligarchiche e quelle democratiche nel sistema sociale e nel sistema politico? E soprattutto: nei sistemi democratici esiste una élite del potere, e con quale fenomenologia, e a quali condizioni?

Per di piú, sui problemi delle élites politiche si è verificato un apparente « rovesciamento di fronte », che contribuisce a confondere ulteriormente il panorama. La teoria che postula l'esistenza del fenomeno elitista come struttura costante della società in generale — e delle società politiche in particolare — nasce storicamente con un’impronta conservatrice. Mosca, liberale comunemente considerato conservatore, è influenzato, nella redazione della giovanile Teorica, dal Taine; la sociologia delle élites è, per Pareto, il momento di passaggio dal liberalismo del Cours all’estrema destra e all’adesione al fascismo; del pari la scoperta della legge ferrea dell’oligarchia è certamente il displuvio del passaggio di Michels dal socialismo al fascismo.

Le teorie elitiste nascono dunque, storicamente, da una matrice intellettuale e politica conservatrice, e si propongono una critica « da destra » dei regimi liberaldemocratici e dell’ideologia rousseauiana. In un secondo momento, depurato da certi contenuti non funzionali logicamente allo stesso sviluppo della teoria empirica, l’élitismo diventa un presupposto, espresso o sotteso, del pluralismo: delle teorie, cioè, le quali sostengono che le liberaldemocrazie, o poliarchie, costituiscono il sistema ottimale per la difesa delle libertà e per il piú generale sviluppo politico. Tanto per tenerci al filone liberale, possiamo partire dagli italiani Burzio e Dorso, e arrivare alla sistemazione neo-élitista di Ralf Dahrendorf, di Dahl e di Sartori.
CONSIDERAZIONI SULLA FILOSOFIA POLITICA
Authors: Bobbio Norberto
Published: May 2019

Introduzione

In occasione del convegno di Bari su «Tradizione e novità della filosofia della politica », la mia relazione distingueva quattro significati dell'espressione ‘filosofia politica’: a) ricerca della miglior forma di governo o dell'ottima repubblica; b) ricerca del fondamento dello stato e conseguente giustificazione (o ingiustificazione) dell'obbligo politico; c) ricerca della natura della politica o meglio della politicità, e conseguente distinzione tra politica e morale; d) analisi del linguaggio politico e metodologia della scienza politica.

L' esigenza di questa distinzione nasceva dalla constatazione che alla categoria della filosofia politica si sogliono assegnare opere apparentemente molto diverse come la Repubblica di Platone, il Contratto sociale di Rousseau, e la Filosofia del diritto di Hegel. Recentemente, in seguito a quella che è stata chiamata la svolta linguistica del filosofare, e alla crescente importanza assunta dall’analisi dei fondamenti e dalla metodologia delle varie scienze per opera delle correnti neo-positivistiche, si è fatta strada l’idea che, se di filosofia politica si possa ancora parlare, in un contesto culturale in cui i discorsi sui valori, terreno tradizionalmente riservato ai filosofi, vengono assegnati alle differenti ideologie, questa si risolva tutta quanta nell'analisi dei modi e degli strumenti con cui si fa scienza dei fenomeni politici.
Roman Triumphs and Etruscan Kings: The Changing Face of the Triumph
Authors: Warren Larissa Bonfante
Published: May 2019

The triumph, to a Roman of the later Republic and Empire, seemed sacred and all of a piece. Its venerable antiquity was more important than its origin or development. So on the one hand Roman antiquarians agreed the triumph was as ancient as Romulus himself; and on the other its antiquity was felt to be confirmed rather than impaired by the connection of many details with the Etruscans—though the ancients never claimed, as modern scholars have done, that the institution itself was borrowed from the Etruscans. It was simply neither important nor desirable to pin down precisely the dates or phases of such a hallowed celebration.

Of course it is not true that there were no changes. Yet the Roman attitude may have also affected modern historians, who until rather recently have been satisfied with a kind of ‘unitarian’ view of the triumph as something permanent and immutable, untouched by history; discussions of particular problems, such as the alleged divinization of thetriumphatoror the location of theporta triumphalis, have taken very little account of changes in the triumph itself. Many Roman rituals did, indeed, continue practically unchanged, and it is a peculiarity of Roman history that our most reliable documents for the early period are religious festivals celebrated year after year, rather than written records or histories. But the triumph was, more than other religious festivals, a part of the political life at Rome.
Compliant Parametric Dynamic Movement Primitives
Authors: Ugur Emre , Girgin Hakan
Published: May 2019

In this paper, we propose and implement an advanced manipulation framework that enables parametric learning of complex action trajectories along with their haptic feedback profiles. Our framework extends Dynamic Movement Primitives (DMPs) method with a new parametric nonlinear shaping function and a novel force-feedback coupling term. The nonlinear trajectories of the action control variables and the haptic feedback trajectories measured during execution are encoded with parametric temporal probabilistic models, namely parametric hidden Markov models (PHMMs). PHMMs enable autonomous segmentation of a taught skill based on the statistical information extracted from multiple demonstrations, and learning the relations between the model parameters and the properties extracted from the environment. Hidden states with high-variances in observation probabilities are interpreted as parts of the skill that could not be reliably learned and autonomously executed due to possibly uncertain or missing information about the environment. In those parts, our proposed force-feedback coupling term, which computes the deviation of the actual force feedback from the one predicted by the force-feedback PHMM, acts as a compliance term, enabling a human to scaffold the ongoing movement trajectory to accomplish the task. Our method is verified in a number of tasks including a real pick and place task that involves obstacles of different heights. Our robot, Baxter, successfully learned to generate the trajectory taking into the heights of the obstacles, move its end effector stiffly (and accurately) along the generated trajectory while passing through apertures, and allow human–robot collaboration in the autonomously detected segments of the motion, for example, when the gripper picks up the object whose position is not provided to the robot.
Valuing biodiversity protection: Payment for Environmental Services schemes in Lao PDR
Authors: Scheufele Gabriela , Bennett Jeff
Published: May 2019

The design of a Payment for Environmental Services (PES) scheme that involves setting a ‘pseudo market price’ per unit of environmental service requires the estimation of demand and supply. This paper presents the results of discrete choice experiments aimed at estimating the demand for environmental and social services generated by a wildlife protection PES scheme in two protected areas in Lao PDR. The discrete choice experiments targeted international tourists sampled at Vientiane airport and the urban Lao population sampled in Vientiane City as potential buyers of the environmental and social services provided by the PES scheme. The survey was customised to a developing country context to address diversity in respondents' literacy levels, language limitations of the interviewers, socio-cultural conventions, and limited trust in confidentiality and anonymity of the survey process. The marginal benefits of the environmental services so estimated were used to inform the development of a PES scheme.
The Seventh Answer Set Programming Competition: Design and Results
Authors: GEBSER MARTIN , MARATEA MARCO , RICCA FRANCESCO
Published: May 2019

Answer Set Programming (ASP) is a prominent knowledge representation language with roots in logic programming and non-monotonic reasoning. Biennial ASP competitions are organized in order to furnish challenging benchmark collections and assess the advancement of the state of the art in ASP solving. In this paper, we report on the design and results of the Seventh ASP Competition, jointly organized by the University of Calabria (Italy), the University of Genova (Italy), and the University of Potsdam (Germany), in affiliation with the 14th International Conference on Logic Programming and Non-Monotonic Reasoning (LPNMR 2017).
Rolled–crimped cereal rye residue suppresses white mold in no-till soybean and dry bean
Authors: Pethybridge Sarah J. , Brown Bryan J. , Kikkert Julie R. , Ryan Matthew R.
Published: May 2019

White mold caused by the fungus,Sclerotinia sclerotiorumis a devastating disease of soybean (Glycine max) and other leguminous crops, including dry bean (Phaseolus vulgaris). Previous research has demonstrated that no-till planting soybean into rolled–crimped cereal rye residue can enhance weed management, improve soil health and reduce labor requirements in organic production. However, there are limited data on the effects of cereal rye residue on white mold suppression in no-till planted soybean and dry bean. Two field trials were conducted in 2016–2017 (Year 1) and repeated in 2017–2018 (Year 2) to evaluate the potential of cereal rye cover crop residue to suppress white mold in these crops. In each trial (soybean and dry bean), the experimental design was a randomized complete block with two treatments: (1) rolled–crimped cereal rye residue and (2) no cover crop control. Treatment effects on plant population, biomass and yield components varied between the main crops. Compared with the control treatment, cereal rye residue reduced the incidence of white mold in soybean in both years and in dry bean in Year 2. The reduction in white mold in cereal rye residue plots was due to a combination of (1) decreased sclerotial germination (no stipes formed) and (2) increased nonfunctional sclerotial germination defined here as sclerotia that germinated but produced stipes without the expanded cup where asci containing ascospores are formed. Weed density and biomass were lower in cereal rye residue plots in soybean and dry bean, except in Year 1 in soybean when weed biomass was low in both treatments. Our findings indicate that cereal rye residue could help organic and conventional farmers manage white mold in no-till planted soybean and dry bean. Germination of sclerotia resulting in nonfunctional apothecia could potentially exhaust soilborne inoculum in the upper soil profile and reduce infections in subsequent crops.
Broadband CPW-fed circularly polarized antenna for IoT-based navigation system
Authors: Birwal Amit , Singh Sanjeev , Kanaujia Binod Kumar , Kumar Sachin
Published: May 2019

The paper presents a new coplanar waveguide (CPW)-fed rectangular patch antenna with a square-shaped ground plane that can be employed in modern advanced navigation systems. For realizing broad impedance bandwidth in the proposed antenna, a wide slot is introduced in the square ground plane and the rectangular patch is shifted toward the left edge of the ground surface. In addition, by means of introducing square-shaped stubs near the left and right edge of the ground plane, the circular polarization is achieved at L1, L2, and L5 satellite bands. As per the simulation results, the proposed antenna provides a wide impedance bandwidth (S11<−10 dB) of 123% (1.12–4.72 GHz) and 3 dB axial ratio bandwidth of 11% (1.15–1.29 GHz) and 18% (1.5–1.8 GHz) suitable for multipurpose wireless applications. The designed single feed circularly polarized antenna is low profile, small size, light weight and easily integrable with other high-frequency communication devices. To validate radiation performance of the proposed structure, the antenna is fabricated and integrated with the commercially available Global Positioning System (GPS) receiver and it is found that the measured values are in close agreement with the desired results.
Modeling the Measurement: Δ47, Corrections, and Absolute Ratios for Reference Materials
Authors: Olack Gerard , Colman Albert S.
Published: May 2019

Clumped isotope studies on CO2, Δ47, that is the excess in the isotopologue containing both 13C and 18O at mass 47, can be very useful since they can give temperature estimates independent of the bulk isotopic composition. The measurement itself can be affected by a number of items. Here we develop a data processing model to examine the effects different interferences might have on the final calculated value. It incorporates known issues, for example, pressure baseline, 17O excess, and shifts in absolute ratios for primary reference materials and parameters used for 17O correction. We also included linearity effects as well as differences in isotopologue absolute abundances at a given m/z. What normally would be considered acceptable mass spectrometer 45R and 46R linearity can skew Δ47 results. That is 0.04‰/V and −0.04‰/V linearity on 45R and 46R respectively would also cause an apparent shift in the parameters used for 17O corrections. Measurements were made on CO2(g) equilibrated with water, and we were able to match up the effects seen with model results. Linearity and small differences in amplitude between sample and working reference gas affected Δ47 determination, as did apparent shifts in isotopologue abundances under different conditions. This may (partially) account for discrepancies seen in Δ47‐temperature calibrations curves between laboratories. We also developed an easy way to precisely calculate the δ13C and δ18O that works well in spreadsheets without the need for multiple iterations.
Tectonic, Oceanographic, and Climatic Controls on the Cretaceous‐Cenozoic Sedimentary Record of the Australian‐Antarctic Basin
Authors: Sauermilch I. , Whittaker J. M. , Bijl P. K. , Totterdell J. M. , Jokat W.
Published: May 2019

Understanding the patterns and characteristics of sedimentary deposits on the conjugate Australian‐Antarctic margins is critical to reveal the Cretaceous‐Cenozoic tectonic, oceanographic, and climatic conditions in the basin. However, unraveling its evolution has remained difficult due to the different seismic stratigraphic interpretations on each margin and sparse drill sites. Here, for the first time, we collate all available seismic reflection profiles on both margins and use newly available offshore drilling data to develop a consistent seismic stratigraphic framework across the Australian‐Antarctic basins. We find sedimentation patterns similar in structure and thickness, prior to the onset of Antarctic glaciation, enabling the basinwide correlation of four major sedimentary units and their depositional history. We interpret that during the warm and humid Late Cretaceous (~83–65 Ma), large onshore river systems on both Australia and Antarctica resulted in deltaic sediment deposition offshore. We interpret that the onset of clockwise bottom currents during the early Paleogene (~58–48 Ma) formed prominent sediment drift deposits along both continental rises. We suggest that these currents strengthened and progressed farther east through the Eocene. Coevally, global cooling (<48 Ma) and progressive aridification led to a large‐scale decrease in sediment input from both continents. Two major Eocene hiatuses recovered by the Integrated Ocean Discovery Program site U1356A at the Antarctic continental slope likely formed during this preglacial phase of low sedimentation and strong bottom currents. Our results can be used to constrain future paleo‐oceanographic modeling of this region and aid the understanding of the oceanographic changes accompanying the transition from a greenhouse to icehouse world.
Formation and Stability of Same‐Dip Double Subduction Systems
Authors: Pusok Adina E. , Stegman Dave R.
Published: May 2019

A specific configuration of the global subduction system is the “same‐dip” double subduction, which occurs when two parallel subduction zones dip in the same direction. Double subduction convergence rates can be significantly faster than across single subduction systems because of pull by two slabs. However, questions regarding double subduction remain largely unexplored in terms of factors controlling its initiation, duration, and dynamics. In this study, we perform numerical simulations to investigate (i) subduction initiation of a secondary system in a mature single subduction system and (ii) the dynamics and stability of the newly formed system. We start from a single subduction setup, where subduction is already initiated and we stress the system by controlling the convergence rate. Two sets of models (Model A—upper mantle and Model B—deep mantle) are performed, and we compare our results to single and double subduction systems. We find that the forcing needs to overcome the right (front) subduction rate in order to obtain a self‐sustaining double subduction system. However, once initiation of double subduction is successful, the left (rear) subduction dominates the dynamics of the system until simulations reach a steady state with convergence speed‐ups of 2.5 relative to single subduction. Our model results are consistent with previous findings in that convergence rates across double subduction are higher than across single subduction, elevated dynamic pressures are accumulated in between the two slabs, or that the left trench advances while the right trench retreats. Finally, we find that upper mantle models create artificially high pressures in between slabs.
Theory for Deriving Shallow Elasticity Structure From Colocated Seismic and Pressure Data
Authors: Tanimoto Toshiro , Wang Jiong
Published: May 2019

Colocated seismic and pressure data are available at many seismic stations in the world. For frequencies approximately between 0.01 and 0.05 Hz, colocated data show evidence of strong coupling between the atmosphere and the solid Earth, especially when pressure is high. Coherence between vertical seismic data and pressure is often higher than 0.9. Such data provide information for shallow structure in the upper 50–100 m because they show how the Earth responds to surface pressure changes. We present the basic theory and an inversion scheme for shallow structure using surface observables η(f)=Sz/Sp where f is frequency and Sz and Sp are the power spectral densities of vertical seismic data and of surface pressure data. A vertically heterogeneous medium is assumed beneath a station where density, P wave velocity, and S wave velocity change with depth. We show that the integration of the minors for the equations of motion gives a fast algorithm to compute η(f). Using numerical differentiation, we derive depth sensitivity kernels for η(f) with which we invert η(f) for shallow structure, just like we invert phase velocity of surface waves for the Earth structure. Depth sensitivity kernels show that if we take density, bulk modulus, and rigidity as independent parameters, η(f) has no sensitivity to density structure, making it mainly a function of two elastic constants. We present examples of inversion based on this formulation.
Large Impacts, Past and Future, of Ozone‐Depleting Substances on Brewer‐Dobson Circulation Trends: A Multimodel Assessment
Authors: Polvani L. M. , Wang L. , Abalos M. , Butchart N. , Chipperfield M. P. , Dameris M. , Deushi M. , Dhomse S. S. , Jöckel P. , Kinnison D. , Michou M. , Morgenstern O. , Oman L. D. , Plummer D. A. , Stone K. A.
Published: May 2019

Substantial increases in the atmospheric concentration of well‐mixed greenhouse gases (notably CO2), such as those projected to occur by the end of the 21st century under large radiative forcing scenarios, have long been known to cause an acceleration of the Brewer‐Dobson circulation (BDC) in climate models. More recently, however, several single‐model studies have proposed that ozone‐depleting substances might also be important drivers of BDC trends. As these studies were conducted with different forcings over different periods, it is difficult to combine them to obtain a robust quantitative picture of the relative importance of ozone‐depleting substances as drivers of BDC trends. To this end, we here analyze—over identical past and future periods—the output from 20 similarly forced models, gathered from two recent chemistry‐climate modeling intercomparison projects. Our multimodel analysis reveals that ozone‐depleting substances are responsible for more than half of the modeled BDC trends in the two decades 1980–2000. We also find that, as a consequence of the Montreal Protocol, decreasing concentrations of ozone‐depleting substances in coming decades will strongly decelerate the BDC until the year 2080, reducing the age‐of‐air trends by more than half, and will thus substantially mitigate the impact of increasing CO2. As ozone‐depleting substances impact BDC trends, primarily, via the depletion/recovery of stratospheric ozone over the South Pole, they impart seasonal and hemispheric asymmetries to the trends which may offer opportunities for detection in coming decades.
Mafic Minerals in the South Pole‐Aitken Basin
Authors: Zhang Xunyu , Zhu Meng‐Hua , Bugiolacchi Roberto
Published: May 2019

The formation of the South Pole‐Aitken (SPA) basin is thought to excavate the deep crust or mantle because of its large size. The pervasive orthopyroxene‐dominated materials found across the basin suggest that they either represent the SPA impact melt or the excavated materials from the lower crust and/or upper mantle. This study analyzes the relative content and distribution of mafic minerals in the SPA area based on the spectra from small fresh craters. The orthopyroxene‐dominated materials in the nonmare regions are classified into two types based on their distribution and different composition. One is distributed from the center to the edge across the SPA basin and interpreted as the SPA impact melt. The other is Mg richer and generally located in some plagioclase‐rich regions (e.g., some large impact craters/basins and the SPA edge), thought to represent materials from the lower crust and/or upper mantle. For the maria in the SPA area, the basaltic materials in the northwest are found to be richer in olivine and/or clinopyroxene than the southern ones.
In Appreciation of AGU’s Outstanding Reviewers of 2018
Authors: Giampoala Matt
Published: May 2019

As AGU editors recognize the contributions of reviewers, our journals are providing new online tools, such as a short questionnaire for reviewer feedback, to improve the peer-review process itself.
Senator Rips Trump on Anniversary of Plan to Leave Climate Pact
Authors: Showstack Randy
Published: May 2019

The second anniversary of the administration’s announcement of its intent to withdraw from the Paris climate accord drew disdain from Sen. Chris Murphy and several environmental leaders.
Extreme Memory of Initial Conditions in Numerical Landscape Evolution Models
Authors: Kwang J. S. , Parker G.
Published: May 2019

Landscape evolution models (LEMs) are dependent on their initial conditions (ICs). Commonly, LEMs use a horizontal surface with randomized perturbations as their IC and tend toward a steady state under constant forcing. The initial and steady state topographies are inherently linked, but they bear no obvious resemblance to each other. Here we reveal a connection by adding a shallow sinusoidal channel to the IC. This channel transforms into a deep canyon at steady state. Hence, the general behavior of LEMs is to indefinitely preserve topographic features from their ICs. Then we test whether experimental landscapes exhibit a similar behavior. In our experiments, we use the same sinusoidal signal, but find that it is ultimately erased. We believe that the culprit reorganizing processes are lateral channel migration and spatiotemporal variability in incision. Our results imply that LEMs are missing fundamental mechanisms and that long‐term preservation of ICs in erosional environments is unlikely.
A New Artificial Neural Network‐Based Global Three‐Dimensional Ionospheric Model (ANNIM‐3D) Using Long‐Term Ionospheric Observations: Preliminary Results
Authors: Gowtam V. Sai , Tulasi Ram S. , Reinisch B. , Prajapati A.
Published: May 2019

In this paper, we present the preliminary results of a new global three‐dimensional (3‐D) ionospheric model developed using artificial neural networks (ANNs) by assimilating long‐term ionospheric observations from nearly two decades of ground‐based Digisonde, satellite‐based topside sounders, and global positioning system‐radio occultation measurements. The present 3‐D model is named ANN‐based global 3‐D ionospheric model (ANNIM‐3D), which is the extension of previous work on the ANN‐based two‐dimensional ionospheric model by Sai Gowtam and Tulasi Ram (2017a, https://doi.org/10.1002/2017JA024795) and Tulasi Ram et al. (2018, https://doi.org/10.1029/2018JA025559). The vertical electron density profiles derived from ANNIM‐3D model are found to be consistent with the ground‐based incoherent scatter radar observations at Jicamarca and Millstone Hill. The model results have been thoroughly validated and found in good agreement with the ground‐based Digisonde and satellite in situ observations at different altitudes. This model successfully reproduces the large‐scale ionospheric phenomena like diurnal and seasonal variations of equatorial ionization anomaly and its hemispheric asymmetries, ionospheric annual anomaly, and the main ionospheric trough. Also, the present model has predicted the ionospheric response that is consistent with the neutral composition changes and meridional wind circulations during disturbed geomagnetic activity periods. Finally, the merits and limitations of this model and the scope for the potential improvements have been discussed.
Electron Density Retrieval From Truncated Radio Occultation GNSS Data
Authors: Lyu Haixia , Hernández‐Pajares Manuel , Monte‐Moreno Enric , Cardellach Estel
Published: May 2019

This paper summarizes the definition and validation of two complementary new strategies, to invert incomplete Global Navigation Satellite System Radio‐Occultation (RO) ionospheric measurements, such as the ones to be provided by the future EUMETSAT Polar System Second Generation. It will provide RO measurements with impact parameter much below the Low Earth Orbiters' height (817 km): from 500 km down approximately. The first presented method to invert truncated RO data is denoted as Abel‐VaryChap Hybrid modeling from topside Incomplete Global Navigation Satellite System RO data, based on simple First Principles, very precise, and well suited for postprocessing. And the second method is denoted as Simple Estimation of Electron density profiles from topside Incomplete RO data, is less precise, but yields very fast estimations, suitable for Near Real‐Time determination. Both techniques will be described and assessed with a set of 546 representative COSMIC/FORMOSAT‐3 ROs, with relative errors of 7% and 11% for Abel‐VaryChap Hybrid modeling from topside Incomplete Global Navigation Satellite System RO data and Simple Estimation of Electron density profiles from topside Incomplete RO data, respectively, with 20 min and 15 s, respectively, of computational time per occultation in our Intel I7 PC.
On the Role of Stern‐ and Diffuse‐Layer Polarization Mechanisms in Porous Media
Authors: Bücker Matthias , Flores Orozco Adrián , Undorf Sabine , Kemna Andreas
Published: May 2019

Water‐saturated porous media exhibit a low‐frequency (<1 MHz) dispersion of the electrical conductivity caused by the polarization of the electrical double layer (EDL) coating the charged solid‐liquid interface. We develop a mathematical framework describing the polarization caused by field‐induced perturbations of the ion densities in the Stern and the diffuse layer of the EDL for two different geometrical configurations of solid and liquid phase. For spherical grains immersed in an electrolyte we derive an improved analytical description by combining suitable models for diffuse‐ and Stern‐layer polarization. The selected models differ from those usually used in geophysical literature and improve the agreement with the corresponding finite‐element solution significantly. We then employ the validated finite‐element model to examine the EDL in a pore‐constriction geometry, which is often used to study membrane polarization. Here, a suitable analytical model can only be set up for a pure diffuse‐layer polarization. The results for the coupled Stern‐ and diffuse‐layer polarization in both geometries indicate that (1) the polarization of the Stern layer is much stronger than the polarization of the diffuse layer as long as the EDL is not connected at the system scale; (2) this dominance of the Stern‐layer polarization can be observed in both geometries, but (3) the contribution of the diffuse layer increases with increasing compaction as represented by the pore‐constriction geometry; and (4) the contributions of both parts of the EDL reach similar levels, when the EDLs on different surfaces are interconnected at the system scale.
Aperture‐Synthesis Radar Imaging With Compressive Sensing for Ionospheric Research
Authors: Hysell D. L. , Sharma P. , Urco M. , Milla M. A.
Published: May 2019

Inverse methods involving compressive sensing are tested in the application of two‐dimensional aperture‐synthesis imaging of radar backscatter from field‐aligned plasma density irregularities in the ionosphere. We consider basis pursuit denoising, implemented with the fast iterative shrinkage thresholding algorithm, and orthogonal matching pursuit (OMP) with a wavelet basis in the evaluation. These methods are compared with two more conventional optimization methods rooted in entropy maximization (MaxENT) and adaptive beamforming (linearly constrained minimum variance or often “Capon's Method.”) Synthetic data corresponding to an extended ionospheric radar target are considered. We find that MaxENT outperforms the other methods in terms of its ability to recover imagery of an extended target with broad dynamic range. Fast iterative shrinkage thresholding algorithm performs reasonably well but does not reproduce the full dynamic range of the target. It is also the most computationally expensive of the methods tested. OMP is very fast computationally but prone to a high degree of clutter in this application. We also point out that the formulation of MaxENT used here is very similar to OMP in some respects, the difference being that the former reconstructs the logarithm of the image rather than the image itself from basis vectors extracted from the observation matrix. MaxENT could in that regard be considered a form of compressive sensing.
Clinical characteristics of liver failure with hemophagocytic lymphohistiocytosis
Authors: Dong Jinling , Xie Fang , Jia Lin , Li Juan , Hu Zhongjie , Zhu Yueke , Yu Hongwei , Zhao Yujuan , Yao Qinwei , Meng Qinghua
Published: May 2019

Liver failure with hemophagocytic lymphohistiocytosis (HLH) is a life-threatening syndrome with high mortality. The aim of this study was to decipher clinical and laboratory characteristics of hemophagocytic lymphohistiocytosis after definite diagnosis of liver failure and to provide clues for early diagnosis and treatment of HLH in patients with liver failure. Eleven patients diagnosed with liver failure and HLH were retrospectively investigated in this study. All patients presented with jaundice, persistent high-grade fever, pancytopenia, splenomegaly, evidence of hemophagocytes in the bone marrow and laboratory abnormalities indicating HLH. The average interval from the earliest diagnosis of liver failure to a definitive diagnosis of HLH was 17.27 days. Six (54.55%) patients died during follow-up. For patients with liver failure after admission and subsequently definitively diagnosed with HLH, bilirubin and INR were significantly decreased. HLH is definitely diagnosed at an intermediate or late stage when patients have already suffered from liver failure. The initial dose of glucocorticoid (methylprednisolone) was decreased to 1–1.5 mg/kg/d and gradually reduced thereafter. In conclusion, for patients with liver failure, HLH should be screened as early as possible upon persistent fever, splenomegaly and unexplained pancytopenia. For patients with liver failure and HLH, the dosage of glucocorticoid should be reduced to avoid serious side effects.
Generation of a fully erythromycin-sensitive strain of Clostridioides difficile using a novel CRISPR-Cas9 genome editing system
Authors: Ingle Patrick , Groothuis Daphne , Rowe Peter , Huang He , Cockayne Alan , Kuehne Sarah A. , Jiang Weihong , Gu Yang , Humphreys Christopher M. , Minton Nigel P.
Published: May 2019

Understanding the molecular pathogenesis of Clostridioides difficile has relied on the use of ermB-based mutagens in erythromycin-sensitive strains. However, the repeated subcultures required to isolate sensitive variants can lead to the acquisition of ancillary mutations that affect phenotype, including virulence. CRISPR-Cas9 allows the direct selection of mutants, reducing the number of subcultures and thereby minimising the likelihood of acquiring additional mutations. Accordingly, CRISPR-Cas9 was used to sequentially remove from the C. difficile 630 reference strain (NCTC 13307) two ermB genes and pyrE. The genomes of the strains generated (630Δerm* and 630Δerm*ΔpyrE, respectively) contained no ancillary mutations compared to the NCTC 13307 parental strain, making these strains the preferred option where erythromycin-sensitive 630 strains are required. Intriguingly, the cas9 gene of the plasmid used contained a proximal frameshift mutation. Despite this, the frequency of mutant isolation was high (96% and 89% for ermB and pyrE, respectively) indicating that a functional Cas9 is still being produced. Re-initiation of translation from an internal AUG start codon would produce a foreshortened protein lacking a RuvCI nucleolytic domain, effectively a ‘nickase’. The mutation allowed cas9 to be cloned downstream of the strong Pthl promoter. It may find application elsewhere where the use of strong, constitutive promoters is preferred.
Resonance excitation of surface capillary waves to enhance material removal for laser material processing
Authors: Ly Sonny , Guss Gabe , Rubenchik Alexander M. , Keller Wesley J. , Shen Nan , Negres Raluca A. , Bude Jeff
Published: May 2019

The results of detailed experiments and high fidelity modeling of melt pool dynamics, droplet ejections and hole drilling produced by periodic modulation of laser intensity are presented. Ultra-high speed imaging revealed that melt pool oscillations can drive large removal of material when excited at the natural oscillation frequency. The physics of capillary surface wave excitation is discussed and simulation is provided to elucidate the experimental results. The removal rates and drill through times as a function of driving frequency is investigated. The resonant removal mechanism is driven by both recoil momentum and thermocapillary force but the key observation is the latter effect does not require evaporation of material, which can significantly enhance the efficiency for laser drilling process. We compared the drilling of holes through a 2 mm-thick Al plate at modulation frequencies up to 20 kHz. At the optimal frequency of 8 kHz, near the resonant response of the melt pool, the drilling efficiency is greater than 10x with aspect ratio of 12:1, and without the collateral damage that is observed in unmodulated CW drilling.
CSN5 inhibition triggers inflammatory signaling and Rho/ROCK-dependent loss of endothelial integrity
Authors: Majolée Jisca , Pronk Manon C. A. , Jim Kin K. , van Bezu Jan S. M. , van der Sar Astrid M. , Hordijk Peter L. , Kovačević Igor
Published: May 2019

RhoGTPases regulate cytoskeletal dynamics, migration and cell-cell adhesion in endothelial cells. Besides regulation at the level of guanine nucleotide binding, they also undergo post-translational modifications, for example ubiquitination. RhoGTPases are ubiquitinated by Cullin RING ligases which are in turn regulated by neddylation. Previously we showed that inhibition of Cullin RING ligase activity by the neddylation inhibitor MLN4924 is detrimental for endothelial barrier function, due to accumulation of RhoB and the consequent induction of contractility. Here we analyzed the effect of pharmacological activation of Cullin RING ligases on endothelial barrier integrity in vitro and in vivo. CSN5i-3 induced endothelial barrier disruption and increased macromolecule leakage in vitro and in vivo. Mechanistically, CSN5i-3 strongly induced the expression and activation of RhoB and to lesser extent of RhoA in endothelial cells, which enhanced cell contraction. Elevated expression of RhoGTPases was a consequence of activation of the NF-κB pathway. In line with this notion, CSN5i-3 treatment decreased IκBα expression and increased NF-κB-mediated ICAM-1 expression and consequent adhesion of neutrophils to endothelial cells. This study shows that sustained neddylation of Cullin RING-ligases leads to activation the NF-κB pathway in endothelial cells, elevated expression of RhoGTPases, Rho/ROCK-dependent activation of MLC and disruption of the endothelial barrier.
Oxidation of hydroxide ions in weak basic solutions using boron-doped diamond electrodes: effect of the buffer capacity
Authors: Irkham Irkham , Einaga Yasuaki
Published: May 2019

The electrochemical oxidation of hydroxide ions using boron-doped diamond (BDD) electrodes in weak basic solutions was examined.
A stability-indicating method by LC-UV for analysis of 7-epi-clusianone extracted fromGarcinia brasiliensisfruits and a novel prenylated benzophenone from the oxidation of this molecular marker
Authors: Castro Aline Pereira , Morais Ruela André Luís , Amaral Juliano Geraldo , dos Santos Marcelo Henrique , Pereira Gislaine Ribeiro , Marques Marcos José
Published: May 2019

The potential of 7-epi-clusianone (7-EPI), a natural prenylated benzophenone extracted from fruits ofGarcinia brasiliensis, as a drug candidate with antimicrobial, antileishmanial, and anti-inflammatory activities has been reported.
Ambient electrochemical N2 reduction to NH3 under alkaline conditions enabled by a layered K2Ti4O9 nanobelt
Authors: Wu Dan , Wang Huanbo , Huang Hong , Zhang Rong , Ji Lei , Chen Hongyu , Luo Yonglan , You Jinmao , Tang Dianping , Zhang Zhonghai , Sun Xuping
Published: May 2019

A K2Ti4O9 nanobelt effectively electrocatalyzes ambient N2-to-NH3 fixation. In 0.1 M KOH, a NH3 yield of 22.88 μg h−1 mg−1cat. and a faradaic efficiency of 5.87% are attained, with good selectivity and high electrochemical stability.
Aptamer-based regulation of transcription circuits
Authors: Pan Linqiang , Hu Yingxin , Ding Taoli , Xie Chun , Wang Zhiyu , Chen Zhekun , Yang Jing , Zhang Cheng
Published: May 2019

We propose synthetic DNA/RNA transcription circuits based on specific aptamer recognition.
Guidelines for the assembly of hydrogen-bonded macrocycles
Authors: Aparicio F. , Mayoral M. J. , Montoro-García C. , González-Rodríguez D.
Published: May 2019

This article highlights selected examples on the synthesis of hydrogen-bonded macrocycles from ditopic molecules and analyze the main factors, often interrelated, that influence the equilibrium between ring and chain species.
Nickel-catalysed direct α-olefination of alkyl substituted N-heteroarenes with alcohols
Authors: Das Jagadish , Vellakkaran Mari , Banerjee Debasis
Published: May 2019

Ni-catalysed α-olefination of alkylheteroarenes with primary alcohols via dehydrogenative coupling is presented. A simple catalytic protocol gave good to excellent yields of E-selective olefins with olefin/alkane selectivity of >20 : 1.
Synthesis of bicyclic ethers by a palladium-catalyzed oxidative cyclization-redox relay-π-allyl-Pd cyclization cascade reaction
Authors: Lux Michaelyn C. , Boby Melissa L. , Brooks Joshua L. , Tan Derek S.
Published: May 2019

A redox-relay process links two successive Pd-catalyzed cyclization reactions at remote sites to afford bicyclic ether products from readily available linear diene–diol substrates.
Determining the kinetics of desolvation of a TNT/aniline solvate
Authors: Lee Yong Joon , Fondren Nadia S. , Weeks Brandon L.
Published: May 2019

The kinetic desolvation process of TNT/aniline solvates was investigated using various experimental techniques.