bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combined Effects of Atmospheric and Seafloor Iron Fluxes to the Glacial Ocean
Authors: Muglia Juan , Somes Christopher J. , Nickelsen Levin , Schmittner Andreas 
Published: October 2017

AbstractChanges in the ocean iron cycle could help explain the low atmospheric CO2 during the Last Glacial Maximum (LGM). Previous modeling studies have mostly considered changes in aeolian iron fluxes, although it is known that sedimentary and hydrothermal fluxes are important iron sources for today's ocean. Here we explore effects of preindustrial‐to‐LGM changes in atmospheric dust, sedimentary, and hydrothermal fluxes on the ocean's iron and carbon cycles in a global coupled biogeochemical‐circulation model. Considering variable atmospheric iron solubility decreases LGM surface soluble iron fluxes compared with assuming constant solubility. This limits potential increases in productivity and export production due to surface iron fertilization, lowering atmospheric CO2 by only 4 ppm. The effect is countered by a decrease in sedimentary flux due to lower sea level, which increases CO2 by 15 ppm. Assuming a 10 times higher iron dust solubility in the Southern Ocean, combined with changes in sedimentary flux, we obtain an atmospheric CO2 reduction of 13 ppm. The high uncertainty in the iron fluxes does not allow us to determine the net direction and magnitude of variations in atmospheric CO2 due to changes in the iron cycle. Our model does not account for changes to iron‐binding ligand concentrations that could modify the results. We conclude that when evaluating glacial‐interglacial changes in the ocean iron cycle, not only surface but also seafloor fluxes must be taken into account.
Widespread Increases in Iron Concentration in European and North American Freshwaters
Authors: Björnerås C. , Weyhenmeyer G. A. , Evans C. D. , Gessner M. O. , Grossart H.‐P. , Kangur K. , Kokorite I. , Kortelainen P. , Laudon H. , Lehtoranta J. , Lottig N. , Monteith D. T. , Nõges P. , Nõges T. , Oulehle F. , Riise G. , Rusak J. A. , Räike A. , Sire J. , Sterling S. , Kritzberg E. S. 
Published: October 2017

AbstractRecent reports of increasing iron (Fe) concentrations in freshwaters are of concern, given the fundamental role of Fe in biogeochemical processes. Still, little is known about the frequency and geographical distribution of Fe trends or about the underlying drivers. We analyzed temporal trends of Fe concentrations across 340 water bodies distributed over 10 countries in northern Europe and North America in order to gain a clearer understanding of where, to what extent, and why Fe concentrations are on the rise. We found that Fe concentrations have significantly increased in 28% of sites, and decreased in 4%, with most positive trends located in northern Europe. Regions with rising Fe concentrations tend to coincide with those with organic carbon (OC) increases. Fe and OC increases may not be directly mechanistically linked, but may nevertheless be responding to common regional‐scale drivers such as declining sulfur deposition or hydrological changes. A role of hydrological factors was supported by covarying trends in Fe and dissolved silica, as these elements tend to stem from similar soil depths. A positive relationship between Fe increases and conifer cover suggests that changing land use and expanded forestry could have contributed to enhanced Fe export, although increases were also observed in nonforested areas. We conclude that the phenomenon of increasing Fe concentrations is widespread, especially in northern Europe, with potentially significant implications for wider ecosystem biogeochemistry, and for the current browning of freshwaters.
Midlatitude Summer Drying: An Underestimated Threat in CMIP5 Models?
Authors: Douville H. , Plazzotta M. 
Published: October 2017

AbstractEarly assessments of the hydrological impacts of global warming suggested both an intensification of the global water cycle and an expansion of dry areas. Yet these alarming conclusions were challenged by a number of latter studies emphasizing the lack of evidence in observations and historical simulations, as well as the large uncertainties in climate projections from the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Here several aridity indices and a two‐tier attribution strategy are used to demonstrate that a summer midlatitude drying has recently emerged over the northern continents, which is mainly attributable to anthropogenic climate change. This emerging signal is shown to be the harbinger of a long‐term drying in the CMIP5 projections. Linear trends in the observed aridity indices can therefore be used as observational constraints and suggest that the projected midlatitude summer drying was underestimated by most CMIP5 models. Mitigating global warming therefore remains a priority to avoid dangerous impacts on global water and food security.
Can Atmospheric Reanalysis Data Sets Be Used to Reproduce Flooding Over Large Scales?
Authors: Andreadis Konstantinos M. , Schumann Guy J.‐P. , Stampoulis Dimitrios , Bates Paul D. , Brakenridge G. Robert , Kettner Albert J. 
Published: October 2017

AbstractFloods are costly to global economies and can be exceptionally lethal. The ability to produce consistent flood hazard maps over large areas could provide a significant contribution to reducing such losses, as the lack of knowledge concerning flood risk is a major factor in the transformation of river floods into flood disasters. In order to accurately reproduce flooding in river channels and floodplains, high spatial resolution hydrodynamic models are needed. Despite being computationally expensive, recent advances have made their continental to global implementation feasible, although inputs for long‐term simulations may require the use of reanalysis meteorological products especially in data‐poor regions. We employ a coupled hydrologic/hydrodynamic model cascade forced by the 20CRv2 reanalysis data set and evaluate its ability to reproduce flood inundation area and volume for Australia during the 1973–2012 period. Ensemble simulations using the reanalysis data were performed to account for uncertainty in the meteorology and compared with a validated benchmark simulation. Results show that the reanalysis ensemble capture the inundated areas and volumes relatively well, with correlations for the ensemble mean of 0.82 and 0.85 for area and volume, respectively, although the meteorological ensemble spread propagates in large uncertainty of the simulated flood characteristics.
Assessing the Roles of Fire Frequency and Precipitation in Determining Woody Plant Expansion in Central U.S. Grasslands
Authors: Brunsell N. A. , Van Vleck E. S. , Nosshi M. , Ratajczak Z. , Nippert J. B. 
Published: October 2017

AbstractWoody plant expansion into grasslands and savannas is occurring and accelerating worldwide and often impacts ecosystem processes. Understanding and predicting the environmental and ecological impacts of encroachment has led to a variety of methodologies for assessing its onset, transition, and stability, generally relying on dynamical systems approaches. Here we continue this general line of investigation to facilitate the understanding of the roles of precipitation frequency and intensity and fire frequency on the conversion of grasslands to woody‐dominated systems focusing on the central United States. A low‐dimensional model with stochastic precipitation and fire disturbance is introduced to examine the complex interactions between precipitation and fire as mechanisms that may suppress or facilitate increases in woody cover. By using Lyapunov exponents, we are able to ascertain the relative control exerted on woody encroachment through these mechanisms. Our results indicate that precipitation frequency is a more important control on woody encroachment than the intensity of individual precipitation events. Fire, however, exerts a much more dominant impact on the limitation of encroachment over the range of precipitation variability considered here. These results indicate that fire management may be an effective strategy to slow the onset of woody species into grasslands. While climate change might predict a reduced potential for woody encroachment in the near future, these results indicate a reduction in woody fraction may be unlikely when considering anthropogenic fire suppression.
U‐Pb Dating and Lu‐Hf Isotopes of Detrital Zircons From the Southern Sikhote‐Alin Orogenic Belt, Russian Far East: Tectonic Implications for the Early Cretaceous Evolution of the Northwest Pacific Margin
Authors: Liu Kai , Zhang Jinjiang , Wilde Simon A. , Liu Shiran , Guo Feng , Kasatkin Sergey A. , Golozoubov Vladimir V. , Ge Maohui , Wang Meng , Wang Jiamin 
Published: October 2017

AbstractThe Sikhote‐Alin orogenic belt in Russian Far East is comprised of several N‐S trending belts, including the Late Jurassic to Early Cretaceous accretionary prisms and turbidite basin which are now separated by thrusts and strike‐slip faults. The origin and collage of the belts have been studied for decades. However, the provenance of the belts remains unclear. Six sandstone samples were collected along a 200 km long east‐west traverse across the major belts in the southern Sikhote‐Alin for U‐Pb dating and Lu‐Hf isotope analysis to constrain the provenance and evaluate the evolution of the northwest Pacific margin at this time. The result reveals that the sediments from the main Samarka belt was mainly from the adjacent Bureya‐Jiamusi‐Khanka Block (BJKB); the eastern Samarka belt and the Zhuravlevka turbidite basin were supplied by detritus from both the North China Craton (NCC) and the BJKB; the Taukha belt was mainly fed by sediments from the NCC; whereas the data from the Sergeevka nappes are insufficient to resolve their provenance. In the Late Jurassic to Early Cretaceous, collision and subduction was important in the initial collage of most belts in Sikhote‐Alin. However, merely E‐W trending collage cannot explain the increasing importance of the NCC provenance from west to east. It is proposed that the main Samarka belt was located adjacent to the BJKB when deposited, whereas the other belts were farther south to accept the materials from the NCC. Sinistral strike‐slip faulting transported the eastern belts northward after their initial collage by thrusting.
Document Clustering
Authors: Anastasiu David C. , Tagarelli Andrea 
Published: October 2017

AbstractIn a world flooded with information, document clustering is an important tool that can help categorize and extract insight from text collections. It works by grouping similar documents, while simultaneously discriminating between groups. In this article, we provide a brief overview of the principal techniques used to cluster documents and introduce a series of novel deep‐learning‐based methods recently designed for the document clustering task. In our overview, we point the reader to salient works that can provide a deeper understanding of the topics discussed.
Mixed Finite Element Methods
Authors: Auricchio F. , da Veiga L. Beirão , Brezzi F. , Lovadina C. 
Published: October 2017

AbstractWithin the well‐known and highly effective finite element method for the computation of approximate solutions of complex boundary value problems, we focus on the often‐calledmixed finite element methods, where in our terminology the word “mixed” indicates the fact that the problem discretization typically results in a linear algebraic system characterized by a null matrix on the main diagonal.Accordingly, the goals of the present article are (i) to sketch out that several physical problems share such an algebraic structure once a discretization is introduced; (ii) to present a simple, algebraic version of the abstract theory that rules most applications of mixed finite element methods; (iii) to give several examples of efficient mixed finite element methods; and (iv) finally, to give some hints on how to perform a stability and error analysis, focusing on a representative problem.
Homogenization Methods and Multiscale Modeling: Nonlinear Problems
Authors: Geers Marc G. D. , Kouznetsova Varvara G. , Matouš Karel , Yvonnet Julien 
Published: October 2017

AbstractThis article focuses on computational multiscale methods for the mechanical response of nonlinear heterogeneous materials. After a short historical note, a brief overview is given of some recent activities in the field, with a particular focus on nonlinear homogenization methods. The two‐scale nonlinear computational homogenization (CH) scheme for mechanics is presented, along with details on representative unit cell aspects and statistics. Model performance is advocated through a decoupled implementation and multiscale schemes based on the nonuniform transformation field analysis. High‐performance parallel multiscale implementations of the CH scheme are addressed in more detail.
Clock Evolution and Adaptation: Whence and Whither?
Authors: Johnson Carl Hirschie , Kyriacou Charalambos P. 
Published: October 2017

AbstractThe sections in this article areIntroductory QuotationSetting the Stage: The Appearance of Circadian ClocksPutative Selective PressuresCyanobacteria and the First Clock GenesThe Appearance of Clocks in Photosynthetic EukaryotesClocks are Widespread in Plants: Mosses, Gymnosperms and AngiospermsRhythms Controlled by the ‘Clockwork Green’Why not an Hourglass Timer?The Clock as an Adaptation: Past and PresentThe Circadian Clock as an AdaptationExperimental Tests of Adaptive Significance before 1980Laboratory Studies of Circadian Clocks and Reproductive Fitness since 1980Evidence that the Clock is Still Adaptive from Studies of Organisms in Natural EnvironmentsClocks: Where did they come from? What are they Doing Now?Acknowledgements
Control of Phosphoenolpyruvate Carboxylase in Plants
Authors: Nimmo Hugh G. 
Published: October 2017

AbstractThe sections in this article areIntroductionPPCKGenes and Their RolesSignalling Pathways that ControlPPCKExpression inCAMandC4PlantsThe ‘Bacterial‐Type’PEPCConclusionsAcknowledgements
The Organization and Control of Plant Mitochondrial Metabolism
Authors: McDonald Allison E. , Vanlerberghe Greg C. 
Published: October 2017

AbstractThe sections in this article areIntroductionOrganization of the Tricarboxylic Acid Cycle and Mitochondrial Electron Transport ChainPosttranslational Control of Mitochondrial Metabolism and FunctionIntegration of Mitochondrial Metabolism with Other Metabolic PathwaysMitochondrial Metabolism of Reactive Oxygen SpeciesAdditional Stress‐Induced Metabolic Pathways Associated with Plant MitochondriaConcluding RemarksAcknowledgements
Composition of Plant Cuticular Waxes
Authors: Jetter Reinhard , Kunst Ljerka , Samuels A. Lacey 
Published: October 2017

Abstract
The sections in this article are

Methods Used for the Chemical Analysis of Plant Cuticular Waxes

Chemical Profiles of Plant Cuticular Waxes

Spontaneous Reactions of Cuticular Wax Constituents

Quantitative Composition of Cuticular Waxes

Dynamics of Wax Composition

Arrangement of Plant Cuticular Waxes
Microbial Communities in the Phyllosphere
Authors: Leveau Johan H.J. 
Published: October 2017

AbstractThe sections in this article areIntroductionMethodologies in Phyllosphere MicrobiologyGetting to the Phyllosphere (and Leaving again)Microbial Communities in the PhyllosphereMicrobial Perception of the PhyllosphereSurviving (or not) in the PhyllosphereMicrobial Growth in the PhyllosphereMicrobial Interactivities in the PhyllosphereBiocontrol in the PhyllosphereFuture Directions of Phyllosphere Microbiology
Filamentous Fungi on Plant Surfaces
Authors: Carver Tim L.W. , Gurr Sarah J. 
Published: October 2017

AbstractThe sections in this article areIntroductionAdhesion Prior to GerminationInfluence of Leaf Surface Characteristics on Spore GerminationDirectional Emergence of Fungal Germ TubesThe Special Case of thePGTofB.graminisAGTGrowth, Appressorium Differentiation and PenetrationEntry into the Host LeafConclusionsAcknowledgements
Ice‐Templated Protein Nanoridges Induce Bone Tissue Formation
Authors: Yang Mingying , Shuai Yajun , Sunderland Kegan S. , Mao Chuanbin 
Published: October 2017

AbstractLittle is known about the role of biocompatible protein nanoridges in directing stem cell fate and tissue regeneration due to the difficulty in forming protein nanoridges. Here an ice‐templating approach is proposed to produce semi‐parallel pure silk protein nanoridges. The key to this approach is that water droplets formed in the protein films are frozen into ice crystals (removed later by sublimation), pushing the surrounding protein molecules to be assembled into nanoridges. Unlike the flat protein films, the unique protein nanoridges can induce the differentiation of human mesenchymal stem cells (MSCs) into osteoblasts without any additional inducers, as well as the formation of bone tissue in a subcutaneous rat model even when not seeded with MSCs. Moreover, the nanoridged films induce less inflammatory infiltration than the flat films in vivo. This work indicates that decorating biomaterials surfaces with protein nanoridges can enhance bone tissue formation in bone repair.
Printable Fabrication of Nanocoral‐Structured Electrodes for High‐Performance Flexible and Planar Supercapacitor with Artistic Design
Authors: Lin Yuanjing , Gao Yuan , Fan Zhiyong 
Published: October 2017

AbstractPlanar supercapacitors with high flexibility, desirable operation safety, and high performance are considered as attractive candidates to serve as energy‐storage devices for portable and wearable electronics. Here, a scalable and printable technique is adopted to construct novel and unique hierarchical nanocoral structures as the interdigitated electrodes on flexible substrates. The as‐fabricated flexible all‐solid‐state planar supercapacitors with nanocoral structures achieve areal capacitance up to 52.9 mF cm−2, which is 2.5 times that of devices without nanocoral structures, and this figure‐of‐merit is among the highest in the literature for the same category of devices. More interestingly, due to utilization of the inkjet‐printing technique, excellent versatility on electrode‐pattern artistic design is achieved. Particularly, working supercapacitors with artistically designed patterns are demonstrated. Meanwhile, the high scalability of such a printable method is also demonstrated by fabrication of large‐sized artistic supercapacitors serving as energy‐storage devices in a wearable self‐powered system as a proof of concept.
Remarkable Enhancement of the Hole Mobility in Several Organic Small‐Molecules, Polymers, and Small‐Molecule:Polymer Blend Transistors by Simple Admixing of the Lewis Acid p‐Dopant B(C6F5)3
Authors: Panidi Julianna , Paterson Alexandra F. , Khim Dongyoon , Fei Zhuping , Han Yang , Tsetseris Leonidas , Vourlias George , Patsalas Panos A. , Heeney Martin , Anthopoulos Thomas D. 
Published: October 2017

AbstractImproving the charge carrier mobility of solution‐processable organic semiconductors is critical for the development of advanced organic thin‐film transistors and their application in the emerging sector of printed electronics. Here, a simple method is reported for enhancing the hole mobility in a wide range of organic semiconductors, including small‐molecules, polymers, and small‐molecule:polymer blends, with the latter systems exhibiting the highest mobility. The method is simple and relies on admixing of the molecular Lewis acid B(C6F5)3 in the semiconductor formulation prior to solution deposition. Two prototypical semiconductors where B(C6F5)3 is shown to have a remarkable impact are the blends of 2,8‐difluoro‐5,11‐bis(triethylsilylethynyl)anthradithiophene:poly(triarylamine) (diF‐TESADT:PTAA) and 2,7‐dioctyl[1]‐benzothieno[3,2‐b][1]benzothiophene:poly(indacenodithiophene‐co‐benzothiadiazole) (C8‐BTBT:C16‐IDTBT), for which hole mobilities of 8 and 11 cm2 V−1 s−1, respectively, are obtained. Doping of the 6,13‐bis(triisopropylsilylethynyl)pentacene:PTAA blend with B(C6F5)3 is also shown to increase the maximum hole mobility to 3.7 cm2 V−1 s−1. Analysis of the single and multicomponent materials reveals that B(C6F5)3 plays a dual role, first acting as an efficient p‐dopant, and secondly as a microstructure modifier. Semiconductors that undergo simultaneous p‐doping and dopant‐induced long‐range crystallization are found to consistently outperform transistors based on the pristine materials. Our work underscores Lewis acid doping as a generic strategy towards high performance printed organic microelectronics.
18F‐flortaucipir tau positron emission tomography distinguishes established progressive supranuclear palsy from controls and Parkinson disease: A multicenter study
Authors: Schonhaut Daniel R. , McMillan Corey T. , Spina Salvatore , Dickerson Bradford C. , Siderowf Andrew , Devous Michael D. , Tsai Richard , Winer Joseph , Russell David S. , Litvan Irene , Roberson Erik D. , Seeley William W. , Grinberg Lea T. , Kramer Joel H. , Miller Bruce L. , Pressman Peter , Nasrallah Ilya , Baker Suzanne L. , Gomperts Stephen N. , Johnson Keith A. , Grossman Murray , Jagust William J. , Boxer Adam L. , Rabinovici Gil D. 
Published: October 2017

Objective18F‐flortaucipir (formerly 18F‐AV1451 or 18F‐T807) binds to neurofibrillary tangles in Alzheimer disease, but tissue studies assessing binding to tau aggregates in progressive supranuclear palsy (PSP) have yielded mixed results. We compared in vivo 18F‐flortaucipir uptake in patients meeting clinical research criteria for PSP (n = 33) to normal controls (n = 46) and patients meeting criteria for Parkinson disease (PD; n = 26).MethodsParticipants underwent magnetic resonance imaging and positron emission tomography for amyloid‐β (11C‐PiB or 18F‐florbetapir) and tau (18F‐flortaucipir). 18F‐flortaucipir standardized uptake value ratios were calculated (t = 80–100 minutes, cerebellum gray matter reference). Voxelwise and region‐of‐interest group comparisons were performed in template space, with receiver operating characteristic curve analyses to assess single‐subject discrimination. Qualitative comparisons with postmortem tau are reported in 1 patient who died 9 months after 18F‐flortaucipir.ResultsClinical PSP patients showed bilaterally elevated 18F‐flortaucipir uptake in globus pallidus, putamen, subthalamic nucleus, midbrain, and dentate nucleus relative to controls and PD patients (voxelwise p < 0.05 family wise error corrected). Globus pallidus binding best distinguished PSP patients from controls and PD (area under the curve [AUC] = 0.872 vs controls, AUC = 0.893 vs PD). PSP clinical severity did not correlate with 18F‐flortaucipir in any region. A patient with clinical PSP and pathological diagnosis of corticobasal degeneration had severe tau pathology in PSP‐related brain structures with good correspondence between in vivo 18F‐flortaucipir and postmortem tau neuropathology.Interpretation18F‐flortaucipir uptake was elevated in PSP versus controls and PD patients in a pattern consistent with the expected distribution of tau pathology. Ann Neurol 2017;82:622–634
Organic Thiocarboxylate Electrodes for a Room‐Temperature Sodium‐Ion Battery Delivering an Ultrahigh Capacity
Authors: Zhao Hongyang , Wang Jianwei , Zheng Yuheng , Li Ju , Han Xiaogang , He Gang , Du Yaping 
Published: October 2017

AbstractOrganic room‐temperature sodium‐ion battery electrodes with carboxylate and carbonyl groups have been widely studied. Herein, for the first time, we report a family of sodium‐ion battery electrodes obtained by replacing stepwise the oxygen atoms with sulfur atoms in the carboxylate groups of sodium terephthalate which improves electron delocalization, electrical conductivity and sodium uptake capacity. The versatile strategy based on molecular engineering greatly enhances the specific capacity of organic electrodes with the same carbon scaffold. By introducing two sulfur atoms to a single carboxylate scaffold, the molecular solid reaches a reversible capacity of 466 mAh g−1 at a current density of 50 mA g−1. When four sulfur atoms are introduced, the capacity increases to 567 mAh g−1 at a current density of 50 mA g−1, which is the highest capacity value reported for organic sodium‐ion battery anodes until now.