bluuebunny/crossref_metadata_2025_split huggingface dataset:
A multi-proxy study of changing environmental conditions in a Younger Dryas sequence in southwestern Manitoba, Canada, and evidence for an extraterrestrial event
Authors: Teller James , Boyd Matthew , LeCompte Malcolm , Kennett James , West Allen , Telka Alice , Diaz Aura , Adedeji Victor , Batchelor Dale , Mooney Charles , Garcia Roberto 
Published: October 2019

AbstractMulti-proxy analyses of a sequence spanning the Younger Dryas (YD) in the Glacial Lake Hind basin of Manitoba provides insight into regional paleohydrology and paleovegetation of meltwater rivers and lakes spanning >4000 yr; the sequence is controlled by 25 new accelerator mass spectrometry ages. This lake, dammed by the Laurentide Ice Sheet, overflowed into Lake Agassiz. The pre-YD interval records rapid sedimentation from meltwaters that headed in proglacial lakes in the Canadian Prairies that are known to have been catastrophically released when ice or sediment barriers were breached. Pollen in this phase is dominated by pre-Quaternary forms eroded from Paleocene bedrock. At the onset of the YD at ~12.8 cal ka, the sudden appearance of concentrations of nanodiamonds, high-temperature magnetic spherules, platinum, and iridium provide evidence of an extraterrestrial (ET) event that others have identified at more than 40 sites in North America. Major changes in oceans and climate, and the catastrophic outflow of nearby Lake Agassiz at the onset of the YD, may be related. Lower water levels and a reduction of Souris River inflow to Lake Hind followed, which are reflected by more clayey and organic-rich sediments and a decrease in pre-Quaternary palynomorphs. This may have resulted from the deepening of river valleys caused by the release of meltwater triggered by the ET event. Wetlands then began to develop, leading to peat deposition from 12.3 to 11 cal ka. This was followed by a fluvial episode depositing sand and then by increased Holocene aridity that resulted in accumulation of a thick sequence of dune sands. A dry woodland environment with a mix of conifers (especially Picea and Larix) and deciduous trees (especially Populus and Quercus) covered the uplands from ~13 to 10 cal ka.
Postglacial sedimentation in the White Sea (northwestern Russia) reconstructed by integrated microfossil and geochemical data
Authors: Budko Dmitry F. , Demina Liudmila L. , Novichkova Ekaterina A. , Polyakova Yelena I. , Kravchishina Marina D. , Melenevsky Vasily N. 
Published: October 2019

AbstractThe White Sea being connected with the Arctic Ocean via the Barents Sea has an influence on its water temperature/salinity structures and biological processes and thus has an indirect impact on the Eurasian climate system. In this work, we have managed to find a correspondence between the climate fluctuation in the Holocene and changes in the geochemical and microfossil properties in the sediment core of the White Sea. For the first time, the element speciation in the sediment core covering about 10,000 cal yr BP period was investigated. The cooling periods (the early Holocene and the Subboreal stage) were characterized by a trend of increase in Si, Al, and Ti contents and Ti/Al ratios, which reflect lithogenous contribution, and decrease in geochemically labile forms of trace elements. A significant increase in the content of organic-bound trace elements and biogenic components (Сorg, BSi, and chlorin) was observed during periods of Holocene climatic optimums. The evident relationship between the metal speciation and indicators of the sedimentation paleoenvironment is observed at the stage of the active phase of early diagenesis after the slowing down of the biogeochemical processes. Down-core decrease in the Mn oxyhydroxide content exhibited a weakening of diagenesis processes at the ~130–150 cm depth.
EL MUNDO EN UNA NUEZ: DE CALCUTA Y CANTÓN A BUENOS AIRES EN UNA ÉPOCA DE GUERRA. LA INTRODUCCIÓN DE EFECTOS ASIÁTICOS EN LOS MERCADOS SURAMERICANOS, 1805–1807
Authors: Ibarra Antonio 
Published: October 2019

ABSTRACTThis article explores the impact of Asian goods in the Rio de la Plata area through the navigation course of two frigates of the Royal Company of Phillipines, forced by the maritime conflict between the Spanish and British Empires, dock in the Southern estuary. Examining the value and traits of the shipment and the details of the ‘comercio de pacotilla’, this study analyzes the distribution of the goods from China, Philippines and in particular, India, in the port basin, the hinterland of the Viceroyalty, and its connections to the Alto Peruvian space, the trans-Andean region, and the Littoral way to Paraguay. This episode enables an understanding of the distribution of goods, as well as a more detailed recognition of the actors of this traffic and a renewed evaluation of the role of the company in the global market of Asian goods.
Chinese Outbound Investment in Australia: From State Control to Entrepreneurship
Authors: Li Wei , Hendrischke Hans 
Published: October 2019

AbstractThis article contributes to our understanding of Chinese corporate expansion into developed economies by using Australia as a case study of how, in the 2010s, Chinese firms began transiting from government-driven resource investment to entrepreneurial expansion in new industries and markets. We contextualize this process by demonstrating how changing market demand and institutional evolutions at home and in the host country created new motivations for Chinese investors. In particular, the decline of active government control in China over the overseas operations of Chinese firms and the more business-oriented regulatory regime in Australia empowered local subsidiaries of Chinese firms to become more entrepreneurial and explorative in their attempts to compensate for their lack of competitiveness and weak organizational capabilities. Consequently, Chinese firms brought their domestic experience and modus operandi to the Australian host market and collectively adapted and deployed dynamic capabilities such as the use of network linkages, experiential learning and corporate reconfiguration. We find that this transfer of capabilities was facilitated by the co-evolution of the Chinese and Australian institutional and market environments and has maintained Australia's position as one of the major recipient countries of Chinese outbound investment, opening the Australian economy to ongoing expansion and disruption.
Reshaping the Policy Arena: How the Agro-Export Policy Network Propelled Brazil within Global Agricultural Governance
Authors: Søndergaard Niels , Dias da Silva Ricardo 
Published: October 2019

AbstractThe article analyzes how Brazil has become an increasingly active voice for liberalization within global spheres of agricultural governance. With the focus on domestic institutional developments, we identify the gradual materialization of an agro-export policy network consisting of public and private actors. We conduct a periodization of the overarching phases of the policy network's development, from its incipient formation during the Uruguay Round to a high degree of organizational refinement in the new millennium. Through analysis of its external linkages, internal structure, and the distribution of resources, we examine how this network became an absolutely central factor in spurring the offensive orientation and assertive engagement of Brazil within the global agricultural policy arena. We thereby provide a domestically rooted explanation for the rise of Brazil as a central agricultural ‘player’, with the focus on the collective agency capacity of public and private stakeholders.
Air‐Sea Heat and Momentum Fluxes in the Southern Ocean
Authors: Bharti Vidhi , Fairall Christopher W. , Blomquist Byron W. , Huang Yi , Protat Alain , Sullivan Peter P. , Siems Steven T. , Manton Michael J. 
Published: October 2019

AbstractThe Clouds, Aerosols, Precipitation, Radiation, and atmospherIc Composition Over the southeRn oceaN (CAPRICORN) experiment was carried out in March–April 2016 onboard R/V Investigator studying momentum (τ), sensible heat (Hs), and latent heat (Hl) fluxes over the Australian sector of the Southern Ocean including over one cyclonic cold‐core and one anticyclonic warm‐core mesoscale oceanic eddy. The turbulence‐based flux measurements obtained with the NOAA PSD flux system employing eddy covariance (EC) and inertial dissipation (ID) methods are compared with those obtained by the Coupled Ocean‐Atmosphere Response Experiment (COARE) 3.5 bulk model, and the neutral transfer coefficients are studied. The relative uncertainty between the turbulence‐based and COARE 3.5 estimates of τ, Hs, and Hl are 22%, 70%, and 26%, respectively, at 1‐hr time scale over the Southern Ocean. Further, the variability in bulk fluxes is investigated with respect to oceanic eddies, precipitation events, atmospheric stability, and extratropical cyclones encountered during the voyage. The main observed variability is an increase in significant wave height or γw (∼33%), τ (∼89%), Hs (∼187%), and Hl (∼79%) over the warm eddy as compared to average voyage values. During the passage of six extratropical cyclones, an increase in τ (∼62% average) and a decrease in Hs (∼235%) and Hl (∼79%) is noted in the warm sector, compared to prestorm conditions, but the pattern reverses behind the cold front.
Uncertainty in the Evolution of Climate Feedback Traced to the Strength of the Atlantic Meridional Overturning Circulation
Authors: Lin Yuan‐Jen , Hwang Yen‐Ting , Ceppi Paulo , Gregory Jonathan M. 
Published: October 2019

AbstractIn most coupled climate models, effective climate sensitivity increases for a few decades following an abrupt CO2 increase. The change in the climate feedback parameter between the first 20 years and the subsequent 130 years is highly model dependent. In this study, we suggest that the intermodel spread of changes in climate feedback can be partially traced to the evolution of the Atlantic Meridional Overturning Circulation. Models with stronger Atlantic Meridional Overturning Circulation recovery tend to project more amplified warming in the Northern Hemisphere a few decades after a quadrupling of CO2. Tropospheric stability then decreases as the Northern Hemisphere gets warmer, which leads to an increase in both the lapse‐rate and shortwave cloud feedbacks. Our results suggest that constraining future ocean circulation changes will be necessary for accurate climate sensitivity projections.
The Effect of Turbulence on Drifting Snow Sublimation
Authors: Wang Zhengshi , Huang Ning , Pähtz Thomas 
Published: October 2019

AbstractSublimation of drifting snow, which is significant for the balances of mass and energy of the polar ice sheet, is a complex physical process with intercoupling between ice crystals, wind field, temperature, and moisture. Here a three‐dimensional drifting snow sublimation model in a turbulent boundary layer is proposed. In contrast to most previous models, it takes into account turbulent diffusion of moisture from lower to higher elevations, allowing the air humidity near the surface to be undersaturated and thus sublimation to occur. From simulations with this model, we find that snow sublimation in the saltation layer near the surface dominates overall snow sublimation, despite an only marginal departure from humidity saturation (<1%), because of a large particle concentration.
Fe Alloy Slurry and a Compacting Cumulate Pile Across Earth's Inner‐Core Boundary
Authors: Zhang Youjun , Nelson Peter , Dygert Nick , Lin Jung‐Fu 
Published: October 2019

AbstractSeismic observations show a reduced compressional‐wave velocity gradient at the base of the outer core relative to the preliminary reference Earth model and seismic wave asymmetry between the east‐west hemispheres at the top of the inner core. Here we propose a model for the inner core boundary (ICB), where a slurry layer forms through fractional crystallization of an Fe alloy at the base of the outer core (F layer) above a compacting cumulate pile at the top of the inner core (F′ layer). Using recent mineral physics data, we show that fractional crystallization of an Fe alloy (e.g., Fe‐Si‐O) with a solid fraction of ~15 ± 5% and preferential light element partitioning into the liquid can explain the observed reduced velocity gradient in the F layer. The compacting cumulate pile in the F′ layer may exhibit lateral variations in thickness between the east‐west hemispheres due to lateral variations of large‐scale heat flux in the outer core, which may explain the east‐west asymmetry observed in the seismic velocity. Our model suggests that the inner core solid has a high shear viscosity >1022 Pa/s.
Progression Features of Dart Leaders in Natural Negative Cloud‐to‐Ground Lightning Flashes
Authors: Huang Haitao , Wang Daohong , Wu Ting , Takagi Nobuyuki 
Published: October 2019

AbstractWe have analyzed the propagation process of nine dart leaders in four natural negative lightning flashes observed by a high speed optical system LAPOS 5. The propagation speeds range from 0.6 to 3.7×107 m/s with an average value of 1.5×107 m/s. The leader luminosity peaks at the front part of the leader head and decreases gradually backward within the head. The leader channel behind the leader head has a relatively low and constant luminosity. The average luminosity of the leader head is about 1.3 times brighter than that of the leader channel behind. The head lengths of seven dart leaders were estimated to range from 21 to 88 m. Our results show that as the ground is approached, the dart leader propagates faster with its leader head growing brighter and longer. For different strokes within an individual lightning flash, it was found that the larger change ratio of leader head brightness relates with the larger change ratio of propagation speed and the larger change ratio of leader head length.
Experimental Subseasonal‐to‐Seasonal (S2S) Forecasting of Atmospheric Rivers Over the Western United States
Authors: DeFlorio Michael J. , Waliser Duane E. , Ralph F. Martin , Guan Bin , Goodman Alexander , Gibson Peter B. , Asharaf Shakeel , Monache Luca Delle , Zhang Zhenhai , Subramanian Aneesh C. , Vitart Frederic , Lin Hai , Kumar Arun 
Published: October 2019

AbstractA multimodel evaluation of subseasonal‐to‐seasonal (S2S) hindcast skill of atmospheric rivers (ARs) out to 4‐week lead over the western United States is presented for three operational hindcast systems: European Centre for Medium‐Range Weather Forecasts (ECMWF; Europe), National Centers for Environmental Prediction (NCEP; U.S.), and Environment and Canada Climate Change (ECCC; Canada). Ensemble mean biases and Brier Skill Scores are examined for no, moderate, and high levels of AR activity (0, 1–2, and 3–7 AR days/week, respectively). All hindcast systems are more skillful in predicting no and high AR activity relative to moderate activity. There are isolated regions of skill at week‐3 over 150–125°W, 25–35°N for the no and high AR activity levels, with larger magnitude and spatial extent of the skill in ECMWF and ECCC compared to NCEP. The spatial pattern of this skill suggests that for high AR activity, a southwest‐to‐northeast orientation is more predictable at subseasonal lead times than other orientations, and for no AR activity, more skill exists in the subtropical North Pacific, upstream of central and southern California. AR hindcast skill along the western U.S. is most strongly increased in hindcasts initialized during Madden‐Julian Oscillation (MJO) Phases 1 and 8, and hindcast skill is substantially decreased over California in hindcasts initialized during MJO Phase 4. Skill modulations in the ECMWF hindcast system conditioned on El Niño‐Southern Oscillation phase are weaker than those conditioned on particular MJO phases. This work provides hindcast skill benchmarks and uncertainty quantification for experimental real‐time forecasts of AR activity during winters 2019–2021 as part of the S2S Prediction Project Real‐time Pilot Initiative in collaboration with the California Department of Water Resources.
Twenty‐First‐Century Changes in the Eastern Mediterranean Etesians and Associated Midlatitude Atmospheric Circulation
Authors: Dafka Stella , Toreti Andrea , Zanis Prodromos , Xoplaki Elena , Luterbacher Juerg 
Published: October 2019

AbstractThe Etesians are the dominant synoptically driven winds observed in the Eastern Mediterranean, usually from late spring to late summer. Due to the complex topography, the Etesians can be very strong and pose significant environmental hazards, especially over wildfire incidents. This study assesses the impacts of climate change on future Etesians by analyzing the response of the most recent EURO‐CORDEX regional climate simulations at the 12‐km grid resolution over the twenty‐first century. The mean model ensemble projects a significant increase of the Etesians' frequency and intensity under the two emission scenarios RCP4.5 and RCP8.5. This response is connected to an increase in the zonal wind at 200 hPa, a reinforcement of the midlatitude westerly flow, and a decrease in the wave amplitude. These circulation changes accelerate the mid‐to‐high latitude eastward propagation of the large‐scale circulation systems which can favor enhanced ridges over the Balkans. A strengthening and poleward shift of the subtropical jet stream is also projected, connected with stronger subsidence over the Eastern Mediterranean. The projected changes will have profound environmental and societal implications, including the lengthening of the wildfire season and increasing air pollution risk in the region. On the other hand, the current estimate of future wind power potential in the Aegean Sea will be significantly increased by the end of the century, which might have positive impact in the regional economy.
The Physics of Changing Tectonic Regimes: Implications for the Temporal Evolution of Mantle Convection and the Thermal History of Venus
Authors: Weller Matthew B. , Kiefer Walter S. 
Published: October 2019

AbstractGiven similar sizes and compositions, Venus invites comparisons with Earth. While Earth convects in the plate tectonic regime, Venus' current and past tectonic states remain uncertain. Venus' impact crater distribution has led to competing models for its tectonic state, steady (e.g., stagnant lid) or catastrophic (e.g., episodic lid). Terrestrial geochemical evidence and geodynamic models suggest that planets may transition between tectonic states over time. Transitions can be triggered by increasing yield stress due to loss of water or by increasing surface temperature. Here, we revisit the classic endmember models of Venusian tectonics by modeling the transition from stable mobile lid convection into a stable stagnant lid in 3D spherical geometry. Transitions between states are governed by both regional and global scale instabilities, resulting in oscillations in heat flux, velocity, and magma production over Gyr time scales. The thermal and tectonic evolution of a convectively transitioning planet is neither catastrophic nor steady. Volcanism and tectonic yielding may be non‐global in nature. At any given time, portions of the planetary surface may reflect apparently different styles of convection, with some regions being highly active and other regions being sluggish and inactive. For Venus, the implications are that global melt production and resurfacing are a natural consequence of lid‐state evolution, without needing ad hoc resurfacing mechanisms which rely on a single governing lid‐state. Geologic evidence suggests that the transition from mobile lid to stagnant lid is still on‐going. Venus may have lost liquid surface water in the last third of its history.
Synergistic antioxidant capacity of CsNPs and CurNPs against cytotoxicity, genotoxicity and pro-inflammatory mediators induced by hydroxyapatite nanoparticles in male rats
Authors: Mosa Israa F. , Youssef Mokhtar , Kamel Maher , Mosa Osama F. , Helmy Yasser 
Published: October 2019

Abstract
Due to their dynamic characteristics, hydroxyapatite nanoparticles (HAP-NPs) have been employed numerous times in nanomedicine and in tissue engineering, particularly as diagnostic and therapeutic agents. However, there are outstanding findings from various studies that question whether these NPs are safe when they are used in the human body. Therefore, a more in-depth toxicity assessment should be carried out to give a clear answer regarding the fate of these particles. Here we aim to investigate the possible cytotoxicity, genotoxicity and inflammation induced by HAP-NPs, as well as predict the synergistic antioxidative effect of chitosan nanoparticles (CsNPs) and curcumin nanoparticles (CurNPs) in mitigating this pronounced toxicity. The present study was conducted on eighty Wistar male rats, divided into eight equal groups. The results showed that, at the molecular level, HAP-NPs significantly induced gene expression of tumor suppressor protein p53, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and also Kidney Injury Molecule-1 (KIM-1) and Lipocalin-2 (LCN2). In addition, kidney biochemical parameters (total bilirubin, urea, uric acid and creatinine) increased, but albumin levels decreased in the group treated with HAP-NPs alone. Meanwhile, co-treatment with CsNPs and/or CurNPs with HAP-NPs showed an improvement in the activities of the kidney parameters and reduced inflammation. This study shows that the nephrotoxicity mechanism of HAP-NPs may involve various signaling pathways including alterations in biochemical parameters, gene expression of KIM-1 and LCN2 and disturbing the production of cytokines and p53. Furthermore, these insights showed that the combined effect of both CsNPs and CurNPs was more pronounced than the effect of each one on its own.
Understanding biochemistry: structure and function of nucleic acids
Authors: Minchin Steve , Lodge Julia 
Published: October 2019

Abstract
Nucleic acids, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), carry genetic information which is read in cells to make the RNA and proteins by which living things function. The well-known structure of the DNA double helix allows this information to be copied and passed on to the next generation. In this article we summarise the structure and function of nucleic acids. The article includes a historical perspective and summarises some of the early work which led to our understanding of this important molecule and how it functions; many of these pioneering scientists were awarded Nobel Prizes for their work. We explain the structure of the DNA molecule, how it is packaged into chromosomes and how it is replicated prior to cell division. We look at how the concept of the gene has developed since the term was first coined and how DNA is copied into RNA (transcription) and translated into protein (translation).
Single‐phase common‐grounded transformer‐less grid‐tied inverter for PV application
Authors: Vosoughi Naser , Hosseini Seyed Hossein , Sabahi Mehran 
Published: October 2019

In this study, a novel topology for the single‐phase transformerless grid‐connected inverters family is proposed. By using the series–parallel switching conversion of the integrated switched‐capacitor module in a packed unit, several merits can be added to the proposed inverter, such as higher efficiency, boosting ability within a single‐stage operation, and removing the leakage current problem by using the common grounding technique. In this study, a peak current controller strategy is implemented in order to generate the gate pulses of semiconductor switches. Moreover, this strategy is used to control both the active and reactive powers. Therefore, a thoroughly controlled current with a proper quality can be supplied to the grid from a single source renewable energy resource. The operating procedure, design consideration, comparison study, and the experimental results for a 510 W prototype are presented in order to validate the correctness and feasibility of the proposed topology.