bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparing the epidemiology of community- and hospital-associatedClostridium difficileinfections in Northern Ireland, 2012–2016: a population data linkage and case–case study
Authors: Maisa A. , Ross G. , Verlander N.Q. , Fairley D. , Bradley D.T. , Patterson L. 
Published: March 2019

AbstractThe burden of community-associatedClostridium difficileinfection (CA-CDI) has increased. We aimed to describe the epidemiology of CA-CDI to inform future interventions. We used population-based linked surveillance data from 2012 to 2016 to describe socio-demographic factors, ribotype and mortality for all CA (n= 1303) and hospital-associated (HA,n= 1356) CDI. For 483 community-onset (CO) CA-CDI and 287 COHA-CDI cases, a questionnaire on risk factors was completed and we conducted a case–case study using logistic regression models for univariate and multivariable analysis. CA-CDI cases had lower odds of being male (adjusted odds ratio (AOR) 0.71, 95% confidence interval (CI) 0.58–0.87;P< 0.001), and higher odds of living in rural rather than urban settlement (AOR 1.5, 95% CI 1.1–2.1;P= 0.05) compared with HA-CDI cases. The distribution of ribotypes was similar in both groups with RT078 being most prevalent. CDI-specific death was lower in CA-CDI than HA-CDI (7%vs.11%,P< 0.001). COCA-CDI had lower odds of having had an outpatient appointment in the previous 4 weeks compared with COHA-CDI (AOR 0.61; 95% CI 0.41–0.9,P= 0.01) and lower odds of being in a care home or hospice when compared with their own home, than COHA-CDI (AOR 0.66; 95% CI 0.45–0.98 and AOR 0.35; 95% CI 0.13–0.92,P= 0.02). Exposure to gastric acid suppressants (50% in COCA-CDI and 55% in COHA-CDI) and antimicrobial therapy (18% in COCA-CDI and 20% in COHA-CDI) prior to CDI was similar. Our analysis of community-onset cases suggests that other risk factors for COHA-CDI may be equally important for COCA-CDI. Opportunities to safely reduce antibiotic and gastric acid suppressants use should be investigated in all healthcare settings.
Rice scarcity in World War II Macao: the local experience revisited
Authors: VIANA VENUS , KIM KYUNG YEOB 
Published: March 2019

AbstractAfter Hong Kong fell on Christmas Day 1941, the ongoing war threatened life in isolated, neutral Macao. While many scholars have attributed the local people's starvation and suffering to the war, others have highlighted Macao's economic prosperity. To explain the gap between these two narratives, this article explores how the locals dealt with rice scarcity and fared relatively well during the four years of Japanese occupation of the Pearl River Delta. Instead of blaming the shortage solely on the machinations of the Japanese and the rice merchants, we uncover the local people's actions in exacerbating the problem.
Soybean and common ragweed (Ambrosia artemisiifolia) growth in monoculture and mixture
Authors: Barnes Ethann R. , Jhala Amit J. , Knezevic Stevan Z. , Sikkema Peter H. , Lindquist John L. 
Published: March 2019

AbstractUnderstanding how plants alter their growth in response to interplant competition is an overlooked but complex problem. Previous studies have characterized the effect of light and water stress on soybean or common ragweed growth in monoculture, but no study has characterized soybean and common ragweed growth in mixture. A field study was conducted in 2015 and 2016 at the University of Nebraska-Lincoln to characterize the growth response of soybean and common ragweed with different irrigation levels and intraspecific and interspecific interference. The experiment was arranged in a split-plot design with irrigation level (0, 50%, 100% replacement of simulated evapotranspiration) as the main plot and common ragweed density (0, 2, 6, 12 plants m−1 row) as the subplot. Crop- and weed-free controls and three mixture treatments were included as subplots. Periodic destructive samples of leaf area and biomass of different organ groups were collected, and leaf area index (LAI), aboveground biomass partitioning, specific leaf area (SLA), and leaf area ratio (LAR) were calculated. Additionally, soybean and common ragweed yield were harvested, and 100-seed weight and seed production were determined. Soybean did not alter biomass partitioning, SLA, or LAR in mixture with common ragweed. Soybean LAI, biomass, and seed size were affected by increasing common ragweed density. Conversely, common ragweed partitioned less new biomass to leaves and increased SLA in response to increased interference. Common ragweed LAI, biomass, and seed number were reduced by the presence of soybean and increasing common ragweed density; however, seed weight was not affected. Results show that adjustment in biomass partitioning, SLA, and LAR is not the method that soybean uses to remain plastic under competition for light. Common ragweed demonstrated plasticity in both biomass partitioning and SLA, indicating an ability to maintain productivity under intra- and inter-specific competition for light or soil resources.
Response of weedy rice (Oryzaspp.) germplasm from Arkansas to glyphosate, glufosinate, and flumioxazin
Authors: Shrestha Swati , Sharma Gourav , Burgos Nilda Roma , Tseng Te-Ming 
Published: March 2019

AbstractWeedy rice (Oryzaspp.) is one of the most competitive weeds in rice (Oryza sativaL.) production. Rapid growth, high tillering, enhanced ability to uptake fertilizers, asynchronous maturation, seed shattering, and high seedbank longevity makeOryzaspp. more competitive than cultivated rice and highly persistent.Oryzaspp. may be a source of useful traits for crop improvement such as herbicide tolerance. Greenhouse studies were conducted to evaluate the response of 54Oryzaspp. accessions collected between 2008 and 2009 from Arkansas to glyphosate, glufosinate, and flumioxazin applied at field rates. Rice cultivars ‘CL163’ and ‘REX’ were included for comparison. Accessions B20, B2, and S11 and B49, B51, and S59 showed reduced sensitivity to glyphosate and flumioxazin, respectively. These accessions had less than 40% injury 5 wk after treatment (WAT). Rice cultivars (CL163 and REX) were sensitive to both glyphosate and flumioxazin, with more than 95% plant mortality at 5 WAT. On average, blackhull accessions were more tolerant to glyphosate and flumioxazin than strawhull accessions. Dose–response analysis of B20, B2, and S11 confirmed 3- to 8-fold higher tolerance of these accessions to glyphosate. AllOryzaspp. and cultivated rice were not affected by glufosinate applied at 874 g ai ha−1(1X) and were controlled 100% by 1,311 g ai ha−1(1.5X).Oryzaspp. lines with reduced sensitivity to glyphosate and flumioxazin will be studied further for use in rice crop improvement.
Unsupervised Learning Reveals Geography of Global Ocean Dynamical Regions
Authors: Sonnewald Maike , Wunsch Carl , Heimbach Patrick 
Published: March 2019

Dynamically similar regions of the global ocean are identified using a barotropic vorticity (BV) framework from a 20‐year mean of the Estimating the Circulation and Climate of the Ocean state estimate at 1° resolution. An unsupervised machine learning algorithm,K‐means, objectively clusters the standardized BV equation, identifying five unambiguous regimes. Cluster 1 covers 43 ± 3.3% of the ocean area. Surface and bottom stress torque are balanced by the bottom pressure torque and the nonlinear torque. Cluster 2 covers 24.8 ± 1.2%, where the beta effect balances the bottom pressure torque. Cluster 3 covers 14.6 ± 1.0%, characterized by a “Quasi‐Sverdrupian” regime where the beta effect is balanced by the wind and bottom stress term. The small region of Cluster 4 has baroclinic dynamics covering 6.9 ± 2.9% of the ocean. Cluster 5 occurs primarily in the Southern Ocean. Residual “dominantly nonlinear” regions highlight where the BV approach is inadequate, found in areas of rough topography in the Southern Ocean and along western boundaries.
Outgassing of Mantle Volatiles in Compressional Tectonic Regime Away From Volcanism: The Role of Continental Delamination
Authors: Caracausi Antonio , Sulli Attilio 
Published: March 2019

AbstractIn this study we discuss the occurrence of mantle‐derived heat and volatiles (i.e., helium and CO2) feeding hydrothermal systems in a seismically active margin between two convergent plates (African and European) without any signals of volcanism. The helium (He) isotopes clearly indicate a mantle‐derived component in the outgassing volatiles. The estimated mantle‐derived He fluxes are up to two to three orders of magnitude greater than those in a stable continental area. Such high He fluxes cannot be provided by a long‐lasting diffusion, thereby implying a more efficient transport (i.e., advective transport through faults). He data coupled to heat‐He relationship suggest the occurrence of active degassing of magmatic intrusions in this area of continental collisional. Geophysical data indicate the presence of a hot mantle wedge below the outgassing of mantle volatiles and a system of faults cutting the continental crust down to the hot mantle wedge. Here we discuss the hot mantle wedge and possible associated magmatic intrusions as the source of the mantle‐derived volatiles outgassing in the region. We also assessed the output of mantle‐derived CO2 from the investigated hydrothermal basins. The possible occurrence of magma at depth as well as the geometry of the thick‐skinned deformed wedge unambiguously indicates delamination processes that are related to continental subduction. Hence, we show that delamination processes can really produce magma at depth without evidences of volcanism at the surface. Finally, we have also provided the fault systems that work as a network of pathways and actively sustain the advective transfer of the mantle fluids toward the surface.
Dissolved Organic Nitrogen Production and Export by Meridional Overturning in the Eastern Subpolar North Atlantic
Authors: Fernández‐Castro Bieito , Álvarez Marta , Nieto‐Cid Mar , Zunino Patricia , Mercier Herlé , Álvarez‐Salgado Xosé Antón 
Published: March 2019

AbstractDissolved organic matter (DOM) is produced in the surface and exported towards the deep ocean, adding ∼2 PgC/year to the global carbon export. Due to its central role in the Meridional Overturning Circulation, the eastern subpolar North Atlantic (eSPNA) contributes largely to this export. Here we quantify the transport and budget of dissolved organic nitrogen (DON) in the eSPNA, in a box delimited by the OVIDE 2002 section and the Greenland‐Iceland‐Scotland sills. The Meridional Overturning Circulation exports >15.9 TgN/year of DON downward and, contrary to the extended view that these are materials of subtropical origin, up to 33% of the vertical flux derives from a net local DON production of 7.1 ± 2.6 TgN/year. The low C:N molar ratio of DOM production (7.4 ± 4.1) and the relatively short transit times in the eSPNA (3 ± 1 year) suggest that local biogeochemical transformations result in the injection of fresh bioavailable DOM to the deep ocean.
Time of Detection as a Metric for Prioritizing Between Climate Observation Quality, Frequency, and Duration
Authors: Carter B. R. , Williams N. L. , Evans W. , Fassbender A. J. , Barbero L. , Hauri C. , Feely R. A. , Sutton A. J. 
Published: March 2019

AbstractWe advance a simple framework based on “time of detection” for estimating the observational needs of studies assessing climate changes amidst natural variability and apply it to several examples related to ocean acidification. This approach aims to connect the Global Ocean Acidification Observing Network “weather” and “climate” data quality thresholds with a single dynamic threshold appropriate for a range of potential ocean signals and environments. A key implication of the framework is that measurement frequency can be as important as measurement accuracy, particularly in highly variable environments. Pragmatic cost‐benefit analyses based on this framework can be performed to quantitatively determine which observing strategy will accomplish a given detection goal soonest and resolve a signal with the greatest confidence and to assess how the trade‐offs between measurement frequency and accuracy vary regionally.
Identification of Channeling in Pore‐Scale Flows
Authors: Siena Martina , Iliev Oleg , Prill Torben , Riva Monica , Guadagnini Alberto 
Published: March 2019

AbstractWe quantify flow channeling at the microscale in three‐dimensional porous media. The study is motivated by the recognition that heterogeneity and connectivity of porous media are key drivers of channeling. While efforts in the characterization of this phenomenon mostly address processes at the continuum scale, it is recognized that pore‐scale preferential flow may affect the behavior at larger scales. We consider synthetically generated pore structures and rely on geometrical/topological features of subregions of the pore space where clusters of velocity outliers are found. We relate quantitatively the size of such fast channels, formed by pore bodies and pore throats, to key indicators of preferential flow and anomalous transport. Pore‐space spatial correlation provides information beyond just pore size distribution and drives the occurrence of these velocity structures. The latter occupy a larger fraction of the pore‐space volume in pore throats than in pore bodies and shrink with increasing flow Reynolds number.
Multiyear Measurements of Radiation Belt Electrons: Acceleration, Transport, and Loss
Authors: Baker Daniel N. , Hoxie Vaughn , Zhao Hong , Jaynes Allison N. , Kanekal Shri , Li Xinlin , Elkington Scot 
Published: March 2019

AbstractIn addition to clarifying morphological structures of the Earth's radiation belts, it has also been a major achievement of the Van Allen Probes mission to understand more thoroughly how highly relativistic and ultrarelativistic electrons are accelerated deep inside the radiation belts. Prior studies have demonstrated that electrons up to energies of 10 megaelectron volts (MeV) can be produced over broad regions of the outer Van Allen zone on timescales of minutes to a few hours. It often is seen that geomagnetic activity driven by strong solar storms (i.e., coronal mass ejections, or CMEs) almost inexorably leads to relativistic electron production through the intermediary step of intense magnetospheric substorms. In this study, we report observations over the 6‐year period 1 September 2012 to 1 September 2018. We focus on data about the relativistic and ultrarelativistic electrons (E≥5 MeV) measured by the Relativistic Electron‐Proton Telescope sensors on board the Van Allen Probes spacecraft. This work portrays the radiation belt acceleration, transport, and loss characteristics over a wide range of geomagnetic events. We emphasize features seen repeatedly in the data (three‐belt structures, “impenetrable” barrier properties, and radial diffusion signatures) in the context of acceleration and loss mechanisms. We especially highlight solar wind forcing of the ultrarelativistic electron populations and extended periods when such electrons were absent. The analysis includes new display tools showing spatial features of the mission‐long time variability of the outer Van Allen belt emphasizing the remarkable dynamics of the system.
Validation of the Neutron Monitor Yield Function Using Data From AMS‐02 Experiment, 2011–2017
Authors: Koldobskiy Sergey A. , Bindi Veronica , Corti Claudio , Kovaltsov Gennady A. , Usoskin Ilya G. 
Published: March 2019

AbstractThe newly published spectra of protons and helium over time directly measured in space by the Alpha Magnetic Spectrometer (AMS‐02) experiment for the period 2011–2017 provide a unique opportunity to calibrate ground‐based neutron monitors (NMs). Here, calibration of several stable sea level NMs (Inuvik, Apatity, Oulu, Newark, Moscow, Hermanus, and Athens) was performed using these spectra. Four modern NM yield functions were verified: Mi13 (Mishev et al., 2013, https://doi.org/10.1002/jgra.50325), Ma16 (Mangeard et al., 2016, https://doi.org/10.1002/2016JA023515), CM12 (Caballero‐Lopez & Moraal, 2012, https://doi.org/10.1029/2012JA017794), and CD00 (Clem & Dorman, 2000, https://doi.org/10.1023/A:1026508915269), on the basis of the cosmic ray spectra measured by AMS‐02. The Mi13 yield function was found to realistically represent the NM response to galactic cosmic rays. CM12 yield function leads to a small skew in the solar cycle dependence of the scaling factor. In contrast, Ma16 and CD00 yield functions tend to overestimate the NM sensitivity to low‐rigidity (<10 GV) cosmic rays. This effect may be important for an analysis of ground level enhancements, leading to a potential underestimate of fluxes of solar energetic particles as based on NM data. The Mi13 yield function is recommended for quantitative analyses of NM data, especially for ground level enhancements. The validity of the force field approximation was studied, and it was found that it fits well the directly measured proton spectra, within a few percent for periods of low to moderate activity and up to ≈10% for active periods. The results of this work strengthen and validate the method of the cosmic ray variability analysis based on the NM data and yield function formalism and improve its accuracy.
VIIRS Deep Blue Aerosol Products Over Land: Extending the EOS Long‐Term Aerosol Data Records
Authors: Hsu N. C. , Lee J. , Sayer A. M. , Kim W. , Bettenhausen C. , Tsay S.‐C. 
Published: March 2019

AbstractA primary goal of the Deep Blue (DB) project is to create consistent long‐term aerosol data records, suitable for climate studies, using multiple satellite instruments. In order to continue Earth Observing System (EOS)‐era aerosol products into the Joint Polar Satellite System era, we have successfully ported the DB algorithm to process data from the Visible Infrared Imaging Radiometer Suite (VIIRS). Although the basic structure of the VIIRS algorithm is similar to that for the Moderate Resolution Imaging Spectroradiometer (MODIS), many enhancements have been made compared to the MODIS collection 6 (C6) version. Most have also been implemented in the latest MODIS Collection 6.1 (C6.1). For example, a new smoke mask was developed based on the spectral curvature of measured reflectance to distinguish biomass burning smoke from weakly absorbing urban/industrial aerosols. Consequently, a new aerosol‐type flag was added into the VIIRS DB data set. In addition, new dust models have been developed to account for the nonsphericity of mineral dust. As a result, a discontinuity in the retrieved aerosol optical depth (AOD) of Saharan dust plumes seen in MODIS C6 products near the boundary between North Africa and the Atlantic has been much reduced. We have also evaluated the VIIRS and MODIS Terra/Aqua C6.1 AOD against Aerosol Robotic Network data. VIIRS and MODIS retrievals show similar performance; around 80% of matchups agree with Aerosol Robotic Network within the expected error of ±(0.05 + 20)%, indicating that DB can provide consistent AOD through the historical EOS and present Joint Polar Satellite System eras.
Uncertainties in Snowpack Simulations—Assessing the Impact of Model Structure, Parameter Choice, and Forcing Data Error on Point‐Scale Energy Balance Snow Model Performance
Authors: Günther Daniel , Marke Thomas , Essery Richard , Strasser Ulrich 
Published: March 2019

AbstractIn this study, we assess the impact of forcing data errors, model structure, and parameter choices on 1‐D snow simulations simultaneously within a global variance‐based sensitivity analysis framework. This approach allows inclusion of interaction effects, drawing a more representative picture of the resulting sensitivities. We utilize all combinations of a multiphysics snowpack model to mirror the influence of model structure. Uncertainty ranges of model parameters and input data are extracted from the literature. We evaluate a suite of 230,000 model realizations at the snow monitoring station Kühtai (Tyrol, Austria, 1,920 m above sea level) against snow water equivalent observations. The results show throughout the course of 25 winter seasons (1991–2015) and different model performance criteria a large influence of forcing data uncertainty and its interactions on the model performance. Mean interannual total sensitivity indices are in the general order of parameter choice < model structure < forcing error, with precipitation, air temperature, and the radiative forcings controlling the variance during the accumulation period and air temperature and longwave irradiance controlling the variance during the ablation period, respectively. Model skill is highly sensitive to the snowpack liquid water transport scheme throughout the whole winter period and to albedo representation during the ablation period. We found a sufficiently long evaluation period (>10 years) is required for robust averaging. A considerable interaction effect was revealed, indicating that an improvement in the knowledge (i.e., reduction of uncertainty) of one factor alone might not necessarily improve model results.
An Integrated Approach Toward Sustainability via Groundwater Banking in the Southern Central Valley, California
Authors: Ghasemizade Mehdi , Asante Kwabena O. , Petersen Christian , Kocis Tiffany , Dahlke Helen E. , Harter Thomas 
Published: March 2019

AbstractIntensive groundwater withdrawals in California have resulted in depletion of streams and aquifers in some regions. Agricultural managed aquifer recharge (Ag‐MAR) initiatives have recently been piloted in California to mitigate the effects of unsustainable groundwater withdrawals. These initiatives rely on capturing wet‐year water and spreading it on large areas of irrigated agricultural lands to enhance recharge to aquifers. While recharge studies typically consider local effects on aquifer storage, few studies have investigated Ag‐MAR benefits and challenges at a regional scale. Here we used the Integrated Water Flow Model, to evaluate how Ag‐MAR projects can affect streamflows, diversions, pumping, and unsaturated zone flows in the southern Central Valley, California. We further tested the sensitivity of three different spatial patterns of Ag‐MAR, each chosen based on different thresholds of soil suitability, on the hydrologic system. This study investigates how the distribution of Ag‐MAR lands benefit the regional groundwater system and other water balance components. The results suggest that Ag‐MAR benefits vary as a function of the location of Ag‐MAR lands. Stream‐aquifer interactions play a crucial factor in determining the ability to increase groundwater storage in overdrafted basins. The results also indicate that Ag‐MAR projects conducted during the November–April recharge season have implications for water rights outside of the Ag‐MAR season. If not properly monitored, Ag‐MAR can cause a rise of groundwater table into the root zone, negatively impacting sensitive crops. Our work also highlights the benefits of using an integrated hydrologic and management model to evaluate Ag‐MAR at a regional scale.
A Generalized Series Solution for the Boussinesq Equation With Constant Boundary Conditions
Authors: Chor Tomas , Ruiz de Zárate Ailín , Dias Nelson L. 
Published: March 2019

AbstractIn this work we consider the Boussinesq equation applied to a one‐dimensional homogeneous aquifer with constant boundary conditions. Such a problem is generally solved (both analytically and numerically) by transforming it from a boundary value problem into an equivalent initial value problem that has to be solved by means of a trial‐and‐error approach. We devise a method that eliminates the need for trial and error that is purely analytical, which can benefit both numerical and analytical solutions. Furthermore, we present a general series solution that solves this equation analytically with arbitrary precision. The series solution generalizes two particular cases that already exist in the literature. With the new proposed series, the need for any numerical integration of differential equations is removed, and fully analytical benchmark solutions are obtained.