bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seed germination of Cannabis sativa L. under artificially simulated salt stress in vitro culture
Authors: Mishchenko S. V. 
Published: October 2024

Aim. The response of hemp (Cannabis sativa L.) to artificially simulated salt stress in vitro culture was the aim of our research. Methods. The seeds of the Hlyana variety were cultivated under conditions of salt stress, which was artificially simulated by adding a certain salt to the Murashige & Skoog nutrient medium in accordance with the main types of soil salinity: chloride, sulfate, and carbonate salinity. Results. Hemp clearly responded to an increase in the concentration of salts in the nutrient medium, in particular, a decrease in seed germination was observed. The most suitable for cultivation is the nutrient medium with sulfates, and the least – with carbonates (at relatively low concentrations). Conclusions. Test systems (including the concentrations of the studied salts) were developed and tested for salt stress screening. The test systems were selective in their selection. Selective concentrations of salts in the environment are determined as follows: chlorides – 0.25 NaCl, 0.75 % MgCl2 · 6 H2O; sulfates – 0.5 MgSO4 · 7 H2O, 1.0 % Na2SO4; carbonates – 0.15 Na2CO3, 0.30 % NaHCO3. The following straight-line regression equations have been constructed, allowing the use of model data to predict seed germination in practical agriculture, depending on the amount of increase / decrease in salt concentration in the soil.
Studying the composition and anti-radiation properties of sage (Salvia officinalis L.) in wheat seeds
Authors: Shamılov E. N. , Abdullayev A. S. , Shamilli V. E. , Azizov I. V. 
Published: October 2024

Aim. The purpose of the research was to study the chemical composition, develop methods for obtaining an extract from the leaves of Salvia officinalis L. and study their anti-radiation properties of irradiated wheat seeds of the Guneshli variety. Methods. Using qualitative reactions and chromatography, the content of lipids, essential oils, diterpene acids, phenolic compounds, macro- and microelements in plants was determined. Wheat seeds were irradiated using a URI installation (K-25) at a dose rate of 13.4 rad/sec, at a dose of 200 Gy. The amount of chlorophyll pigments, carotenoids, and malondialdehyde was measured using a spectrophotometer. Chlorophyll fluorescence in leaves was determined using a MINI-PAM device. Results. According to the results of morphological and physiological-biochemical parameters of seedlings, 0.01 % and 0.001 % Salvia officinalis extract has a positive effect on growth and development, increases the maximum quantum yield of PS II and reduces the yield of lipid peroxidation product. Conclusions. It has been established that Salvia officinalis extract has a radioprotective effect and can be used as a radioprotector for some agricultural plants.
Assessment of Fusarium wilt (Fusarium oxysporum f.sp. sesami) Disease Incidence in Sesame (Sesamum indicum L.) in Western Tigray, Northern Ethiopia
Authors: Kebede Assefa Abadi , Tsehaye Hadush 
Published: October 2024

Fusarium wilt disease is one of the most serious diseases threatening sesame production in Tigray, northern Ethiopia. The aim of the present study was to assess Fusarium wilt disease incidence and its association with agronomic practices and environmental factors. Field survey was conducted in Kafta-Humera, Welkayt and Tsegedie districts in 2018 cropping season. A total of 92 farmers’ fields were assessed for the prevalence and incidence of the disease. Results indicated that 67% of farmers’ fields were infected by Fusarium wilt disease from the total assessed fields. Fusarium wilt disease incidence was varied from 0.22% to 80%. It was ranged from 0-72% in Kafta-Humera, 0-56% in Welkayt and 0-80% in Tsegedie. The mean disease incidence was 11.89% at Kafta-Humera, 11.14% at Welkayt and 10.69% at Tsegedie. According to the single predictor in the logistic regression model Fusarium wilt disease incidence was most affected significantly (p < 0.05) with the previous crop and altitude. Higher levels of disease incidence were recorded when the previous crop was sesame, lower altitudes and in clay loam soil texture. Overall results of the present study indicated that Fusarium wilt disease is the major challenge to sesame production in study areas. Therefore, efforts should be put in place to manage the disease via integration of appropriate strategies.
Effect of Different Herbicides on Weed Dynamics in Wheat (Triticum aestivum L.)
Authors: Deepak  , Prajapat Arjun Lal , Reema  
Published: October 2024

A field experiment was conducted at Research farm, Vivekananda Global University, Jaipur during Rabi, 2023 on loamy sand soil. The experiment comprises 11 treatments of weed management practices in wheat (Weedy check, Weed free, Hand weeding at 30-35 DAS, 2,4-D ester @ 0.75 kg/ha at 30-35 DAS, Sulfosulfuron @ 25 g a.i. at 30-35 DAS, Carfentrazone ethyl @20 g/ha at 30-35 DAS, Metsulfuron methyl @ 4 g/ha at 30-35 DAS, Pinoxaden @60 g a.i./ha 25-30 DAS, Piroxofop- propargyl 15% WP @60g a.i./ha 30-35 DAS, Sulfosulfuron 75% + Metsulfuron 5% WG @ 32g a.i./ha at 30-35 DAS and Clodinafop-propargyl 15% + Metsulfuron methyl 1% @ 32 g a.i./ha at 30-35 DAS) thereby experiment was laid out in randomized block design and replicated thrice. Results showed that application of Sulfosulfuron 75% + Metsulfuron 5% WG @ 32g a.i./ha at 30-35 DAS at 30-35 DAS treatment resulted significant reduction in weed density, weed dry matter in comparison to most of the treatments while highest weed control efficiency and lowest weed index was recorded with the same treatment except weed free treatment. Clodinafop-propargyl 15% + Metsulfuron methyl 1% @ 32 g a.i./ha at 30-35 DAS was next superior treatment.
Carbonate buffering and metabolic controls on carbon dioxide in rivers
Authors: Stets Edward G. , Butman David , McDonald Cory P. , Stackpoole Sarah M. , DeGrandpre Michael D. , Striegl Robert G. 
Published: March 2017

AbstractMultiple processes support the significant efflux of carbon dioxide (CO2) from rivers and streams. Attribution of CO2 oversaturation will lead to better quantification of the freshwater carbon cycle and provide insights into the net cycling of nutrients and pollutants. CO2 production is closely related to O2 consumption because of the metabolic linkage of these gases. However, this relationship can be weakened due to dissolved inorganic carbon inputs from groundwater, carbonate buffering, calcification, and anaerobic metabolism. CO2 and O2 concentrations and other water quality parameters were analyzed in two data sets: a synoptic field study and nationwide water quality monitoring data. CO2 and O2 concentrations were strongly negatively correlated in both data sets (ρ = −0.67 and ρ = −0.63, respectively), although the correlations were weaker in high‐alkalinity environments. In nearly all samples, the molar oversaturation of CO2 was a larger magnitude than molar O2 undersaturation. We used a dynamically coupled O2CO2 model to show that lags in CO2 air‐water equilibration are a likely cause of this phenomenon. Lags in CO2 equilibration also impart landscape‐scale differences in the behavior of CO2 between high‐ and low‐alkalinity watersheds. Although the concept of carbonate buffering and how it creates lags in CO2 equilibration with the atmosphere is well understood, it has not been sufficiently integrated into our understanding of CO2 dynamics in freshwaters. We argue that the consideration of carbonate equilibria and its effects on CO2 dynamics are primary steps in understanding the sources and magnitude of CO2 oversaturation in rivers and streams.
Comparing the Dynamic Global Core Plasma Model with ground‐based plasma mass density observations
Authors: Jorgensen Anders M. , Heilig Balazs , Vellante Massimo , Lichtenberger Janos , Reda Jan , Valach Fridrich , Mandic Igor 
Published: March 2017

AbstractThe Dynamic Global Core Plasma Model (DGCPM) is an empirical dynamical model of the plasmasphere which, despite its simple mathematical form, or perhaps because of its simple mathematical form, has enjoyed wide use in the space physics modeling community. In this paper we present some recent observations from the European quasi‐Meridional Magnetometer Array (EMMA) and compare these with the DGCPM. The observations suggest more rapid daytime refilling and loss than what is described in the DGCPM. We then modify the DGCPM by changing the values of some of its parameters, leaving the functional form intact. The modified DGCPM agrees much better with the EMMA observations. The modification resulted in an order‐of‐magnitude faster daytime refilling and nighttime loss. These results are also consistent with previous observations of daytime refilling.
Generation of exchange flows in estuaries by tidal and gravitational eddy viscosity‐shear covariance (ESCO)
Authors: Dijkstra Yoeri M. , Schuttelaars Henk M. , Burchard Hans 
Published: March 2017

AbstractWe present a systematic analysis of generation mechanisms for exchange flows in partially stratified estuaries using water column (1DV) and width‐averaged (2DV) numerical models. We focus on exchange flows generated by eddy viscosity‐shear covariance (ESCO). We identify two distinctly different physical mechanisms. The first, tidal ESCO circulation, results from interactions between the barotropic tide and temporal variations of the eddy viscosity. While this flow is mostly generated by direct interactions between the tide and eddy viscosity variations at the main tidal frequency, a similarly important contribution can be attributed to indirect interactions. These are more complex interactions involving eddy viscosity variations at other frequencies than the main tidal frequency (e.g., M4). The second mechanism is called gravitational ESCO circulation. This results from an amplification of the gravitational circulation through indirect interactions between the gravitational circulation and temporal variations of the eddy viscosity at any time scale. Tidal and gravitational ESCO circulations are generated by different mechanisms and have a different dependency on the phase and frequency of eddy viscosity variations and the density gradient. The relative contributions of gravitational circulation and tidal and gravitational ESCO circulation to the exchange flow are typically 1/3 each in tidally energetic well‐mixed or partially stratified estuaries. The results are generalized using an idealized width‐averaged model of the Scheldt River estuary. This model confirms the results of the water column model and additionally shows that temporal variations of turbulence not captured in the water column model have a significant effect on the exchange flow.
Comprehensive modeling study of ozonolysis of oleic acid aerosol based on real‐time, online measurements of aerosol composition
Authors: Gallimore P. J. , Griffiths P. T. , Pope F. D. , Reid J. P. , Kalberer M. 
Published: March 2017

AbstractThe chemical composition of organic aerosols profoundly influences their atmospheric properties, but a detailed understanding of heterogeneous and in‐particle reactivity is lacking. We present here a combined experimental and modeling study of the ozonolysis of oleic acid particles. An online mass spectrometry (MS) method, Extractive Electrospray Ionization (EESI), is used to follow the composition of the aerosol at a molecular level in real time; relative changes in the concentrations of both reactants and products are determined during aerosol aging. The results show evidence for multiple non‐first‐order reactions involving stabilized Criegee intermediates, including the formation of secondary ozonides and other oligomers. Offline liquid chromatography MS is used to confirm the online MS assignment of the monomeric and dimeric products. We explain the observed EESI‐MS chemical composition changes, and chemical and physical data from previous studies, using a process‐based aerosol chemistry simulation, the Pretty Good Aerosol Model (PG‐AM). In particular, we extend previous studies of reactant loss by demonstrating success in reproducing the time dependence of product formation and the evolving particle size. This advance requires a comprehensive chemical scheme coupled to the partitioning of semivolatile products; relevant reaction and evaporation parameters have been refined using our new measurements in combination with PG‐AM.
Numerical simulation of large‐scale bed load particle tracer advection‐dispersion in rivers with free bars
Authors: Iwasaki Toshiki , Nelson Jonathan , Shimizu Yasuyuki , Parker Gary 
Published: March 2017

AbstractAsymptotic characteristics of the transport of bed load tracer particles in rivers have been described by advection‐dispersion equations. Here we perform numerical simulations designed to study the role of free bars, and more specifically single‐row alternate bars, on streamwise tracer particle dispersion. In treating the conservation of tracer particle mass, we use two alternative formulations for the Exner equation of sediment mass conservation: the flux‐based formulation, in which bed elevation varies with the divergence of the bed load transport rate, and the entrainment‐based formulation, in which bed elevation changes with the net deposition rate. Under the condition of no net bed aggradation/degradation, a 1‐D flux‐based deterministic model that does not describe free bars yields no streamwise dispersion. The entrainment‐based 1‐D formulation, on the other hand, models stochasticity via the probability density function (PDF) of particle step length, and as a result does show tracer dispersion. When the formulation is generalized to 2‐D to include free alternate bars, however, both models yield almost identical asymptotic advection‐dispersion characteristics, in which streamwise dispersion is dominated by randomness inherent in free bar morphodynamics. This randomness can result in a heavy‐tailed PDF of waiting time. In addition, migrating bars may constrain the travel distance through temporary burial, causing a thin‐tailed PDF of travel distance. The superdiffusive character of streamwise particle dispersion predicted by the model is attributable to the interaction of these two effects.
Hydrodynamics of mountain‐river confluences and its relationship to sediment transport
Authors: Guillén Ludeña S. , Cheng Z. , Constantinescu G. , Franca M. J. 
Published: March 2017

AbstractMountain confluences are characterized by narrow and steep tributaries that provide important sediment load to the confluence, whereas the main channel supplies the dominant flow discharge. This results in a marked bed discordance between the tributary and main channel which induces key differences in the hydromorphodynamics of the confluence when compared to concordant bed and some common types of discordant bed confluences. The processes of initiation and maintenance of the morphology of confluences are still unknown, and research linking morphodynamics and hydrodynamics of river confluences is required to understand these phenomena. In this paper, eddy‐resolving simulations based on laboratory experiments made in a live‐bed model of a mountain‐river confluence are used to provide a detailed description of flow hydrodynamics and implications for morphodynamics. The test case study corresponds to a confluence with an angle of 70°. Numerical simulations are performed for two extreme bathymetric conditions: those at the start of the experiment and when equilibrium morphological conditions are reached. Results of the simulations and experimental observations are used to make inferences on erosion mechanisms during the initial and final states of the erosion/deposition process. The relationship between the coherent structures present in the near‐bed region in the instantaneous and mean flow fields and sediment entrainment/transport is described. The present paper demonstrates the critical role played by large‐scale turbulence generated in the shear layers forming on the side of the tributary flow as it enters the main channel, by the main vortex forming over the discordant bed region surrounding the downstream end of the tributary, as well as by several near‐bed vortices induced by the deflection of the tributary flow by the incoming flow in the main channel. The predicted patterns of bed shear stress are linked to pathways of sediment movement documented in the laboratory experiments, providing a link between the flow and sediment transport.
A model of three‐dimensional topographic stresses with implications for bedrock fractures, surface processes, and landscape evolution
Authors: Moon S. , Perron J. T. , Martel S. J. , Holbrook W. S. , St. Clair J. 
Published: March 2017

AbstractBedrock fractures influence the rates of surface processes that drive landscape evolution and are in turn influenced by landforms that perturb ambient tectonic and gravitational stress fields. In this modeling study, we examine how three‐dimensional topography and tectonic stress regimes influence elastic stress fields and bedrock fracture patterns beneath Earth's surface. We illustrate general effects of landform orientation and of tectonic stress magnitude and anisotropy using boundary element models of stresses beneath synthetic elongated ridges with different aspect ratios. We then examine the more detailed effects of landform shape using natural landscapes in Colorado and South Carolina. We show that the stress field is most sensitive to topographic perturbations if the most compressive horizontal tectonic stress is oriented perpendicular to the long axis of elongated landforms such as ridges and valleys and that topographic stress perturbations are most pronounced beneath landforms with higher mean curvatures, such as channel junctions and ridge crests. The shape of a predicted fracture‐rich zone in the subsurface depends mainly on the orientation of landforms relative to the most compressive horizontal tectonic stress direction and a dimensionless ratio that expresses the relative magnitudes of topographic stresses associated with horizontal tectonic compression and topographic relief. Variations in this dimensionless ratio can also change the predicted orientations of potential opening‐mode fracture planes. We use these model results to illustrate how topographic perturbations of three‐dimensional tectonic and gravitational stresses could influence landscape evolution by altering the rates and spatial heterogeneity of surface processes and groundwater flow.
Vertical groundwater storage properties and changes in confinement determined using hydraulic head response to atmospheric tides
Authors: Acworth R. Ian , Rau Gabriel C. , Halloran Landon J. S. , Timms Wendy A. 
Published: March 2017

AbstractAccurate determination of groundwater state of confinement and compressible storage properties at vertical resolution over depth is notoriously difficult. We use the hydraulic head response to atmospheric tides at 2 cpd frequency as a tracer to quantify barometric efficiency (BE) and specific storage (Ss) over depth. Records of synthesized Earth tides, atmospheric pressure, and hydraulic heads measured in nine piezometers completed at depths between 5 and 55 m into unconsolidated smectitic clay and silt, sand and gravel were examined in the frequency domain. The barometric efficiency increased over depth from ∼0.05 in silty clay to ∼0.15 in sands and gravels. BE for silty clay was confirmed by calculating the loading efficiency as 0.95 using rainfall at the surface. Specific storage was calculated using effective rather than total moisture. The differences in phase between atmospheric pressure and hydraulic heads at 2 cpd were ∼180° below 10 m indicating confined conditions despite the low BE. Heads in the sediment above a fine sand and silt layer at 12 m exhibited a time variable phase difference between 0° and 180° indicating varying confinement. Our results illustrate that the atmospheric tide at 2 cpd is a powerful natural tracer for quantifying groundwater state of confinement and compressible storage properties in layered formations from hydraulic heads and atmospheric pressure records without the need for externally induced hydraulic stress. This approach could significantly improve the development of conceptual hydrogeological model used for groundwater resource development and management.
Plasma waves in Jupiter's high‐latitude regions: Observations from the Juno spacecraft
Authors: Tetrick S. S. , Gurnett D. A. , Kurth W. S. , Imai M. , Hospodarsky G. B. , Bolton S. J. , Connerney J. E. P. , Levin S. M. , Mauk B. H. 
Published: March 2017

AbstractThe Juno Waves instrument detected a new broadband plasma wave emission (~50 Hz to 40 kHz) on 27 August 2016 as the spacecraft passed over the low‐altitude polar regions of Jupiter. We investigated the characteristics of this emission and found similarities to whistler mode auroral hiss observed at Earth, including a funnel‐shaped frequency‐time feature. The electron cyclotron frequency is much higher than both the emission frequency and local plasma frequency, which is assumed to be ~20–40 kHz. The E/cB ratio was about three near the start of the event and then decreased to one for the rest of the period. A correlation of the electric field spectral density with the flux of an upgoing 20 to 800 keV electron beam was found, with a correlation coefficient of 0.59. We conclude that the emission is propagating in the whistler mode and is driven by the energetic upgoing electron beam.
Al‐andalus and Castile: Art and Identity in the Iberian Peninsula
Authors: Judith Feliciano Maria , Ruiz Souza Juan Carlos 
Published: March 2017

AbstractThe realms of the Crown of Castile present one of the most diverse European monumental landscapes of the early modern period. Castile's constant physical proximity to the Andalusi frontier for nearly 500 years was only outlasted by the process of absorption of Andalusi cities and populations over which it presided and which continued through the expulsion of the Moriscos (converted Muslims) in 1609. The depth, duration, and complexity of the cross‐cultural exchanges that took place between the Castilian and Andalusi populations throughout the medieval period and the first century of the early modern era were unparalleled. It is not surprising, therefore, that the influence of the arts of al‐Andalus reached well into the seventeenth century. At the heart of the process of assimilation of forms that led to the great developments of the early modern period lies the selective integration of Andalusi artistic traditions into the already varied Castilian repertoire. The strength of Andalusi influence waned with time, especially after 1430, when the arrival of northern European and Italian influences and techniques gained great strength. Toward the last decades of the fifteenth century the wealth of classicizing aesthetic information overflowed the markets and began to dominate prominent architectural commissions, paving the way for the emblematic building programs of the sixteenth century. It is within this diversity and freedom of aesthetic experimentation that Andalusi‐derived forms survived, mixed, and transformed alongside late medieval expressions and the great movement of the early modern period: the classicizing vocabulary of the Italian Renaissance.