bluuebunny/crossref_metadata_2025_split huggingface dataset:
Population genetics analyses of North-East Indian indigenous rice landraces revealed divergent history and alternate origin of aroma in aus group
Authors: Chakraborty Debarati , Ray Avik 
Published: September 2019

AbstractThe rice-based agriculture of the Indian subcontinent has been interwoven in the rich socio-cultural fabric of the country. Of which, bio-culturally diverse North-Eastern states nurture thousands of landraces with poorly tapped agronomic traits. In the present study, 27 standard microsatellite data from 171 rice landraces from six states were analysed to understand their genetic diversity and population structure. Further, combining with a global dataset, we determined subpopulation identity using both model-based and multivariate analyses to uncover their history. We found moderate to high genetic diversity and high differentiation [standardized G”ST = 0.57]. The AMOVA partitioned overall variance into within population (75%) and among population (25%). The landraces from six states remained at various degrees of differentiation (pairwise FST = 0.09–0.41). We have detected a preponderance of aus-type in a majority of aromatic landraces. Rests were japonica and admixed with a little representation of indica. The presence of aromatic aus probably implied assimilation into local culture from the primary aus growing region of Bangladesh and India. Likewise, the arrival of japonica may stem from the exchange of goods among neighbouring dynasties via Southern and Southwestern Silk routes. The shared ancestry may reflect a merger of two ancient cultures. Our analyses also uncovered the existence of aus-type short and medium grain aromatic rice predicting an origin of aroma in aus subpopulation. Collectively, it demonstrated the diversity and divergent history of the rice landraces have been shaped by various socio-cultural interactions operative over time and space.
Gender and Democratic Attitudes: Do Women and Men Prioritize Different Democratic Institutions?
Authors: Hansen Michael A. , Goenaga Agustín 
Published: September 2019

AbstractUsing the 2012 European Social Survey (ESS), this article provides the first comparative analysis of how conceptions of democracy differ between men and women in 29 countries, and how this relates to their overall satisfaction with and support for democracy. Women tend to consider less important those aspects of democracy that privilege male resources and power, such as representative institutions, political parties, and the media. Instead, women assign more importance to those aspects of democracy that are less prone to reproduce gender inequalities, such as those related to direct participation (i.e., referenda), public justification of government decisions, and the protection of social rights. These differences are small in size but are comparable to the effects of other individual-level characteristics such as income or education. Finally, gendered differences in conceptions of democracy are not associated with different levels of democratic support. Men and women are most supportive of democracy where they are able to develop differentiated views about which aspects of democracy are most important for them.
Biogeography of N2 Fixation Influenced by the Western Boundary Current Intrusion in the South China Sea
Authors: Lu Yangyang , Wen Zuozhu , Shi Dalin , Lin Wenfang , Bonnet Sophie , Dai Minhan , Kao Shuh‐Ji 
Published: September 2019

AbstractThe N2 fixation and primary production rates were measured simultaneously using 15N2 and 13C incubation assays in the northern South China Sea influenced by the Kuroshio intrusion (KI) seasonally. The degree of KI (KI index, range from 0 to 1) was assessed by applying an isopycnal mixing model. The water column integrated N2 fixation and primary production for stations with KI index larger than 0.5 were 463 ± 260 μmol N·m−2·day−1 and 62 ± 19 mmol C·m−2·day−1, respectively, significantly higher than those for stations with KI index lower than 0.5 (50 ± 10 μmol N·m−2·day−1 and 28 ± 10 mmol C·m−2·day−1, respectively). Trichodesmium was the dominant diazotroph at stations with KI index larger than 0.5, with 2 orders of magnitude higher nifH gene abundance than that at stations with KI index lower than 0.5. However, the highest N2 fixation rates were found in waters with moderate KI index around 0.6, suggesting that frontal zone mixing might stimulate N2 fixation. Our results demonstrated that diazotrophs (mainly Trichodesmium) were tightly associated with the KI, which modulated the biogeographic distribution of N2 fixers. In summary, we found the transportation of Trichodesmium by KI, then, we quantified the fraction of KI and N2 fixation rates in the northern South China Sea. The results suggested that KI generated a new biogeographic regime which could significantly influence the carbon and nitrogen cycles far away from the main stream.
Long‐Term Variations in Nearshore Wave Climate and Littoral Drift at Ganpatipule Coast, Eastern Arabian Sea and its Link to Pacific Climate Variability
Authors: George Jesbin , Kumar V. Sanil 
Published: September 2019

AbstractNearshore wave characteristics and its variations at Ganpatipule coast, eastern Arabian Sea, for the past 4 decades (1979–2016) have been examined. The study is based on European Centre for Medium‐Range Weather Forecasts Re‐Analysis‐Interim wave data at ~50 m water depth and the nearshore wave parameters estimated using the numerical model Simulating WAves Nearshore, executed from the Delft3D dashboard considering shallow water wave propagation, wave setup, and breaking. The littoral drift is estimated based on bulk transport formula of the Coastal Engineering Research Centre with the input from the hydrodynamic module. The model shows good agreement with wave rider buoy measured wave parameters at 14‐m water depth. Anomalies of breaker height, period, and direction vary in the range of −0.35–0.4 m, −0.80–1 s, and − 16 to 12°, respectively during the study period. A detailed analysis of monthly variations of breaker height along the study region suggests a significant increasing trend during the Asian summer monsoon, whereas a decreasing trend is identified during the nonmonsoon period. The study region accounts for a northerly net transport of 3.9 × 105 m3 yr−1 with a significant increasing trend of 1,840 m3 yr−1. The strong wind field region along the central Arabian Sea (65–70°E and 15–20°N) gives a strengthened positive correlation (r > 0.7) with the littoral drift. Impacts of Pacific climate variability on interannual and decadal timescales are observed in the littoral drift rates.
Convergence of Terrestrial Dissolved Organic Matter Composition and the Role of Microbial Buffering in Aquatic Ecosystems
Authors: Harfmann Jennifer L. , Guillemette François , Kaiser Karl , Spencer Robert G. M. , Chuang Chia‐Ying , Hernes Peter J. 
Published: September 2019

AbstractSubstantial changes in vegetation are expected as global climatic patterns shift, altering terrestrial sources of dissolved organic matter (DOM) entering rivers and streams. Since differences in the chemical composition of plant litters are reflected in the DOM that is leached, changes in riparian vegetation can directly influence the bioavailability of DOM to local aquatic microbial communities. We assessed the degradation dynamics and optical compositional changes of DOM from a variety of vascular plant leachates through microbial and coupled photochemical‐microbial degradation pathways. Initial decay rates ranged from 0.029 ± 0.011 day−1 (microbial, mixed wetland) to 0.73 ± 0.62 day−1 (photochemical‐microbial, mixed grasses), and all decay rates decreased to below 0.05 day−1 after 1 week, converging below 0.029 day−1 after 2 weeks. Overall, we found a decrease in leachate optical diversity under microbial and photochemical‐microbial degradations, corresponding to a decrease in degraded leachate sample dispersion using principal component analysis. We show that despite initial variability across DOM leachates, successive degradation promotes kinetic and optical convergence such that, in aquatic environments with long residence times, terrestrial DOM source and composition are much less important on exported DOM composition than historically thought. In these systems, DOM compositional convergence may act as a natural buffer to provide stability of aquatic DOM cycling in the face of future landscape changes.
Stratospheric Initial Condition for Skillful Surface Prediction in the ECMWF Model
Authors: Choi Jung , Son Seok‐Woo 
Published: September 2019

AbstractThe subseasonal‐to‐seasonal prediction of boreal‐winter sea‐level pressure (SLP) is investigated by examining 19‐year reforecast data sets from the European Centre for Medium‐Range Weather Forecasts ensemble prediction system. Based on a pattern anomaly correlation coefficient of 0.6, the model reliably predicted the extratropical SLP anomalies with a maximum forecast lead time of 9.8 days. This prediction skill, however, varies significantly from one forecast to another. The forecasts with relatively high skills and those with low skills exhibit significant zonal Wavenumber 1 patterns in the stratospheric initial conditions with an opposite sign. The high‐skill forecasts present a relatively weak westward Wavenumber 1 phase tilt with height compared with the low‐skill forecasts, dampening an upward wave propagation in the stratosphere. This result suggests that not only the zonal mean but also the zonally asymmetric stratospheric conditions play an important role in extended surface prediction by modulating vertical wave propagation or wave reflection.
Energy Transport by Whistler Waves Around Dipolarizing Flux Bundles
Authors: Zhang Xu , Angelopoulos V. , Artemyev A.V. , Liu Jiang 
Published: September 2019

AbstractDuring whistler wave excitation, electron energy is transferred from electrons to waves. There is little observational evidence that such a process operates effectively in the magnetotail, however. Using a large observational database from the Time History of Events and Macroscale Interactions during Substorms mission, we investigate whistler wave excitation within and around dipolarizing flux bundles (DFBs), critical energy transporters in the magnetotail, and the evacuation of perpendicular electron energy by whistler wave Poynting flux. We find that perpendicular anisotropy of suprathermal (~10 keV) electrons is the major free energy source for whistler wave excitation near DFBs. During earthward transport of electrons by DFBs, 3.7% of the suprathermal electron energy flux is evacuated in the form of whistler wave Poynting flux. This suggests that whistler waves play an important role in electron thermodynamics in the magnetotail by significantly modifying the otherwise adiabatically shaped electron distributions.
Tracking Pyrometeors With Meteorological Radar Using Unsupervised Machine Learning
Authors: McCarthy N. F. , Guyot A. , Protat A. , Dowdy A. J. , McGowan H. 
Published: September 2019

AbstractPyrometeors are the large (>2 mm) debris lofted above wildfires that are composed of the by‐products of combustion of the fuels. One speciation of pyrometeor is firebrands, which are burning debris that lead to ignitions ahead of the surface fire and can be the dominant mechanism of fire spread and structure loss. Pyrometeors are observed by meteorological radar. To date, there have been no investigations into identification of pyrometeor speciation with radar. Here we present an unsupervised machine learning method (Gaussian mixture model) to classify pyrometeor modes using X‐band radar data. The coherent features of the mode of pyrometeor identified most likely to transport firebrands were tracked in time and space. The radar classification and tracking method shows that wildfires do produce signatures in radar returns that could be used for spot fire risk prediction. In wildfires, different types of debris (known as pyrometeors) are lofted in the smoke plumes and transported downwind. Some types of pyrometeors may, when in the air, still be burning and capable of starting new wildfires. Here we investigate the potential for meteorological radar to classify different types of pyrometeors and to track them to determine their potential for starting new fires downwind of the main fire front.
Dynamic Fine‐Scale Sea Icescape Shapes Adult Emperor Penguin Foraging Habitat in East Antarctica
Authors: Labrousse Sara , Fraser Alexander D. , Sumner Michael , Tamura Takeshi , Pinaud David , Wienecke Barbara , Kirkwood Roger , Ropert‐Coudert Yan , Reisinger Ryan , Jonsen Ian , Porter‐Smith Rick , Barbraud Christophe , Bost Charles‐André , Ji Rubao , Jenouvrier Stéphanie 
Published: September 2019

AbstractThe emperor penguin, an iconic species threatened by projected sea ice loss in Antarctica, has long been considered to forage at the fast ice edge, presumably relying on large/yearly persistent polynyas as their main foraging habitat during the breeding season. Using newly developed fine‐scale sea icescape data and historical penguin tracking data, this study for the first time suggests the importance of less recognized small openings, including cracks, flaw leads and ephemeral short‐term polynyas, as foraging habitats for emperor penguins. The tracking data retrieved from 47 emperor penguins in two different colonies in East Antarctica suggest that those penguins spent 23% of their time in ephemeral polynyas and did not use the large/yearly persistent, well‐studied polynyas, even if they occur much more regularly with predictable locations. These findings challenge our previous understanding of emperor penguin breeding habitats, highlighting the need for incorporating fine‐scale seascape features when assessing the population persistence in a rapidly changing polar environment.
Deep Low‐Frequency Earthquakes Beneath the Hakone Volcano, Central Japan, and their Relation to Volcanic Activity
Authors: Yukutake Y. , Abe Y. , Doke R. 
Published: September 2019

AbstractDeep low‐frequency earthquakes (DLFEs) are ubiquitous seismic activities in the deep parts of volcanoes. Owing to the low signal‐to‐noise ratio, the seismic activities of DLFEs have not been characterized in detail; particularly, the linkage between DLFEs and shallow volcanic activity has not been understood sufficiently. In this study, numerous DLFEs have been successfully detected beneath the Hakone volcano, central Japan, by cross‐correlating a template to the continuous seismic signals. The resulting seismic catalog reveals that DLFEs are activated prior to notable earthquake swarms in the shallow part of a volcano and to the crustal expansion caused by a pressure source at a depth of 7 km. Results indicate that the activation of DLFEs reflects the feeding of magmatic fluid from depth. The subsequent increment in the magmatic‐fluid pressure triggers shallow volcanic activities.
A 3‐D Shear Velocity Model of the Crust and Uppermost Mantle Beneath Alaska Including Apparent Radial Anisotropy
Authors: Feng Lili , Ritzwoller Michael H. 
Published: September 2019

AbstractThis paper presents a model of the 3‐D shear velocity structure of the crust and uppermost mantle beneath Alaska and its surroundings on a ~50‐km grid, including crustal and mantle radial anisotropy, based on seismic data recorded at more than 500 broadband stations. The model derives from a Bayesian Monte Carlo inversion of Rayleigh wave group and phase speeds and Love wave phase speeds determined from ambient noise and earthquake data. Prominent features resolved in the model include the following: (1) Apparent crustal radial anisotropy is strongest across the parts of central and northern Alaska that were subjected to significant extension during the Cretaceous. This is consistent with crustal anisotropy being caused by deformationally aligned middle to lower crustal sheet silicates (micas) with shallowly dipping foliation planes beneath extensional domains. (2) Crustal thickness estimates are similar to those from receiver functions by Miller and Moresi (2018, https://doi.org/10.1785/0220180222). (3) Very thick lithosphere underlies Arctic‐Alaska, with high shear wave speeds that extend at least to 120‐km depth, which may challenge rotational transport models for the evolution of the region. (4) Subducting lithosphere beneath Alaska is resolved, including what we call the “Barren Islands slab anomaly,” an “aseismic slab edge” north of the Denali Volcanic Gap, the “Wrangellia slab anomaly,” and Yakutat lithosphere subducting seaward of the Wrangell volcanic field. (5) The geometry of the Alaskan subduction zone generally agrees with the slab model Alaska_3D 1.0 of Jadamec and Billen (2010, https://doi.org/10.1038/nature09053) except for the Yakutat “slab shoulder region,” which is newly imaged in our model.
Novel, Repeated Surveys Reveal New Insights on Sediment Flux Through a Narrow Strait, Bohai, China
Authors: Wu Xiao , Wu Hui , Wang Houjie , Bi Naishuang , Duan Haiqin , Wang Chenghao , Bian Changwei , Xu Jingping 
Published: September 2019

AbstractStraits are both a choke point and passage through which material and energy are exchanged between two adjoining water bodies. Understanding the mechanisms that drive these exchanges therefore is vital to quantifying the water and sediment budgets in regional and global oceans. Here we present a study in which a novel, phase‐averaging method was employed to better estimate the net‐suspended sediment fluxes through the entire Bohai Strait, the only passage for the massive Yellow River‐delivered sediment to leave the enclosed Bohai Sea for the open Yellow Sea. In winter, the transport through the strait was nearly barotropic in waters well mixed by the energetic winter monsoons. The transport became primarily baroclinic (opposite directions between upper and lower layers) in spring due to stratification, especially in the southern part of the strait. Intermittent but frequent southerly winds in northerly dominated winters were responsible for a net westward sediment transport into the Bohai Sea, a finding contrary to a status quo view. Hence, previous studies in which these intermittent southerly wind busts were not included are believed to have overestimated the sediments export from the Bohai Sea.
Spatially Disaggregating Satellite Land Surface Temperature With a Nonlinear Model Across Agricultural Areas
Authors: Liu Kai , Wang Shudong , Li Xueke , Wu Taixia 
Published: September 2019

AbstractAccurate remotely sensed land surface temperature (LST) is a promising tool for predicting surface evapotranspiration (ET). The spatial resolution of commonly existing daily satellite products (i.e., Moderate Resolution Imaging Spectroradiometer [MODIS] LST) is ~1 km, which remains relatively low for used in estimating ET. This paper developed a model that disaggregates ~1‐km spatial resolution MODIS‐derived LST data to fine spatial resolutions of 250 m. The proposed model was achieved by using a spatial and temporal nonlinear strategy that contains the predictor variables of the Bowen ratio, the photochemical reflectance index, and the normalized difference vegetation index. The proposed disaggregation model was assessed mainly at two agriculture sites, including the Heihe River Basin in China and the Walnut Creek Watershed in the United States, during the growing seasons. The assessment procedure was conducted at both the field scale and the image scale in terms of disaggregated LST and ET. The statistical results demonstrated that the proposed model produced 250‐m LST and ET that matched better with the observed values and achieved more accurate LST and ET relative to other reference ones. Our study shows that surface moisture status and vegetation physiological dynamic are important factors in improving the LST disaggregation over the agriculture region. The results of this study have the potential to improve water resource management and sustainable water use.
Topography Modulates Effects of Nitrogen Deposition on Asymbiotic N2 Fixation in Soil but not Litter or Moss in a Secondary Karst Forest
Authors: Wang Zhenchuan , Li Dejun , Zheng Mianhai , Chen Hao , Sun Xibin , Wang Kelin 
Published: September 2019

AbstractEvidence shows that nitrogen (N) addition may suppress or have no significant effect on asymbiotic N2 fixation (ANF) in soil, litter, or moss. However, the mechanisms underlying the differential responses of ANF to N addition are not well understood. The main objectives of the current study were to assess how ANF in soil, litter, and moss responds to N addition and whether topography modulates the responses of ANF in soil, litter, or moss to N addition. We conducted an N addition experiment at two topographic positions, that is, valley and slope of a secondary karst forest in southwest China. Three N addition treatments, that is, control (0 kg N·ha−1·year−1), moderate N addition (N50, 50 kg N·ha−1·year−1), and high N addition (N100, 100 kg N·ha−1·year−1) were included. Nitrogen addition had no significant effect on moss ANF at both topographic positions. Soil ANF was lower by 17.1% in the N100 plots relative to the control in the valley but was not significantly altered by N addition on the slope. In contrast, litter ANF was suppressed by N addition at both topographic positions by 77.9% to 87.4%. Our findings suggest that topography may modulate the responses of ANF to N addition, but the modulation effects likely differ among different ecosystem compartments.
Momentum Transport in Shallow Cumulus Clouds and Its Parameterization by Higher‐Order Closure
Authors: Larson Vincent E. , Domke Steffen , Griffin Brian M. 
Published: September 2019

AbstractIt is challenging to parameterize subgrid vertical momentum fluxes in marine shallow cumulus layers that contain a jet in the profile of horizontal wind. In a large‐eddy simulation of such a layer, it is found that the momentum flux in the direction of strongest wind magnitude has a three‐layer structure. The lowest layer, from the ocean surface up to the jet maximum, has downgradient momentum flux. The middle layer, from the jet maximum up to an altitude several hundred meters above, has upgradient (i.e., countergradient) momentum flux because of transport of low‐magnitude momentum upward through the jet maximum. In the upper layer, the layer‐average momentum flux is weak. The budget of momentum flux shows that in the middle and upper layers, both the buoyancy production term and turbulent advection (i.e., third‐order flux‐of‐flux) terms are important.To parameterize the profile of momentum flux in a single‐column model, the momentum flux is prognosed in this study. The buoyancy production and flux‐of‐flux terms are parameterized by integrating them over a subgrid probability density function with an assumed normal‐mixture shape. The resulting parameterized fluxes and mean‐wind profiles are demonstrated to be comparable to those produced in large‐eddy simulations, both for two marine shallow cumulus cases with upgradient fluxes and for a continental cumulus case and two stratocumulus cases with downgradient fluxes. In the two marine shallow cumulus cases, the parameterization is able to capture the upgradient momentum flux above the jet maximum and the weak momentum fluxes aloft.