1,666 research outputs found

    Nitrogen and Rainfall Effects on Crop Growth—Experimental Results and Scenario Analyses

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    Nitrogen (N) fertilization is critical for crop growth; however, its effect on crop growth and evapotranspiration (ETc) behaviors under different amounts of rainfall is not well understood. As such, there is a need for studying the impact of nitrogen application rates and rainfall amounts on crop growth and ETc components. Agricultural system models help to fill this knowledge gap, e.g., the Root Zone Water Quality Model (RZWQM2), which integrates crop growth-related processes. The objective of this study is to investigate the effect of the nitrogen application rate on crop growth, soil water dynamics, and ETc behavior under different rainfall amounts by using experimental data and the RZWQM2. A field study was conducted from 2016 to 2019 with three nitrogen application rates (0, 70, and 130 kg N ha−1) for unirrigated winter wheat (Triticum aestivum L.), and two nitrogen application rates (0 and 205 kg N ha−1) for unirrigated corn (Zea mays L.). For the period of 1986–2019, the amounts of actual rainfall during each crop growth period are categorized into four groups. Each rainfall group is used as a rainfall scenario in the RZWQM2 to explore the interactions between the rainfall amounts and N levels on the resulting crop growth and water status. The results show that the model satisfactorily captures the interaction effects of nitrogen application rates and rainfall amounts on the daily ETc and soil water dynamics. The nitrogen application rate showed a noticeable impact on the behavior of soil water dynamics and ETc components. The 75% rainfall scenario yielded the highest nitrogen uptake for both crops. This scenario revealed the highest water consumption for wheat, while corn showed the highest water uptake for the 100% rainfall scenario. The interaction between a high nitrogen level and 50% rainfall yielded the highest water use efficiency, while low nitrogen and 125% rainfall yielded the highest nitrogen use efficiency. A zero nitrogen rate yielded the highest ETc and lowest soil water content among all treatments. Moreover, the impacts of the nitrogen application rate on ETc behavior, crop growth, and soil water dynamics differed depending on the received rainfall amount

    Phytochemical Constituents of Leaves Essential oils of Achillea fragrantissima (Asteraceae) from Iraq

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    Essential oils of Achillea fragrantissima extract were prepared and analyzed by gas chromatography–mass spectrometry (GC-MS). A total of 57 phytochemical constituents of chemical compounds were identified in leaves of A. fragrantissima. The major constituents of the essential oil were camphor (34.50%), 1, 8-cineole (14.60%), artemisia ketone (10.25%), and 3-thujanone (7.82%). In addition, 43 components were present at <1%. From the 57 identified compounds, four of them was sesquiterpenes (7.01%), whereas 35 compounds were monoterpenes (61.40%)

    Fuzzy Logic Maximum Structure and State Feedback Control Strategies of the Electrical Car

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    AbstractThis paper treats the design and control of different models and control strategies for an Electric Vehicle (EV). An hybrid controller is designed using a fuzzy logic integrated in Maximum Control Structure (FL-MCS), the FL nonlinear controller involves online estimation of the total reference force which corresponds to a torque reference to be applied to MCS. The second proposed regulator is a states feedback controller using the Linear Quadratic Regulation (LQR) to optimise and to determine the feedback control parameters. The LQR allows reducing the consumption of the energy according to the desired EV's dynamic performances, these lasts can be changed depending on the choice of Q and R matrices. In this work, we apply and validate the proposed control strategies by a comparison between our simulation results and the results of the classical MCS, which has been developed by L2EP (Lille, France) to control the EV speed under Matlab/Simulink

    HYBRID MAXIMUMCONTROL STRUCTUREUSING FUZZY LOGICOF ELECTRIC VEHICLE

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    This paper presents a Modelling of traction control system of an Electric Vehicle (EV) based on the Energetic Macroscopic Representation (EMR) and the Maximum Control Structure (MCS). This last is using Fuzzy Logic Control(FLC) toinvert the EMR accumulation element for the control task. A developed combination of fuzzy control strategy with SMC combines the advantages of these two approaches and facilitates the inversion of the accumulation elements. In order to validate the simulation results, a comparison between the results obtained by MCS using IP controller which has already been developed by L2EP laboratory (Lille, France) and the presented MSC-FLC obtained by Matlab/Simulink software tool is include

    Colorimetric gold nanoparticles-based assay for direct detection of Clostridium difficile in clinical isolates from Qatar

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    Clostridium difficile infection (CDI) is a significant health problem worldwide. Control and prevention strategies of C. difficile horizontal transmission require assays with fast detection with high specificity and sensitivity. Conventional diagnostic methods are time consuming and costly for clinical field settings. This study aims to develop gold nanoparticles (AuNPs)-based assay for direct qualitative detection of the nucleic acid of C. difficile and its toxins. A colloidal solution of AuNPs with a diameter of 13±1 nm was prepared and characterized. The qualitative colorimetric AuNPs assay was developed for restricted genomic C. difficile DNA detection, and results were confirmed by PCR. One hundred and five positive C. difficile isolates were collected from patients with diarrheal diseases and tested using AuNPs based-assay. Ninety-six samples (91.4%) were detected positive using AuNPs based assay, as indicated by the color change from red to blue within 1 min. All ninety-six positive samples were positive for toxin B. In conclusion, nano-gold assay prototype was developed for direct and inexpensive detection of C. difficile. The developed prototypes are simple, sensitive, rapid and can substitute PCR-based detection. The developed assay may show potential in the clinical diagnosis of C. difficile, especially in developing countries as it is less costly as compared to the commercially available assays.NPRP award (NPRP 4-1215-3-317) from the Qatar National Research Fun

    Three-Point Functions in N=4 SYM Theory at One-Loop

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    We analyze the one-loop correction to the three-point function coefficient of scalar primary operators in N=4 SYM theory. By applying constraints from the superconformal symmetry, we demonstrate that the type of Feynman diagrams that contribute depends on the choice of renormalization scheme. In the planar limit, explicit expressions for the correction are interpreted in terms of the hamiltonians of the associated integrable closed and open spin chains. This suggests that at least at one-loop, the planar conformal field theory is integrable with the anomalous dimensions and OPE coefficients both obtainable from integrable spin chain calculations. We also connect the planar results with similar structures found in closed string field theory.Comment: 34 pages, 9 figures, harvmac; references adde

    Multi-scale modeling study of the source contributions to near-surface ozone and sulfur oxides levels over California during the ARCTAS-CARB period

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    Chronic high surface ozone (O_3) levels and the increasing sulfur oxides (SO_x = SO_2 + SO_4) ambient concentrations over South Coast (SC) and other areas of California (CA) are affected by both local emissions and long-range transport. In this paper, multi-scale tracer, full-chemistry and adjoint simulations using the STEM atmospheric chemistry model are conducted to assess the contribution of local emission sourcesto SC O_3 and to evaluate the impacts of transported sulfur and local emissions on the SC sulfur budgetduring the ARCTAS-CARB experiment period in 2008. Sensitivity simulations quantify contributions of biogenic and fire emissions to SC O_3 levels. California biogenic and fire emissions contribute 3–4 ppb to near-surface O_3 over SC, with larger contributions to other regions in CA. During a long-range transport event from Asia starting from 22 June, high SO_x levels (up to ~0.7 ppb of SO_2 and ~1.3 ppb of SO_4) is observed above ~6 km, but they did not affect CA surface air quality. The elevated SO_x observed at 1–4 km is estimated to enhance surface SO_x over SC by ~0.25 ppb (upper limit) on ~24 June. The near-surface SO_x levels over SC during the flight week are attributed mostly to local emissions. Two anthropogenic SO_x emission inventories (EIs) from the California Air Resources Board (CARB) and the US Environmental Protection Agency (EPA) are compared and applied in 60 km and 12 km chemical transport simulations, and the results are compared withobservations. The CARB EI shows improvements over the National Emission Inventory (NEI) by EPA, but generally underestimates surface SC SO_x by about a factor of two. Adjoint sensitivity analysis indicated that SO_2 levels at 00:00 UTC (17:00 local time) at six SC surface sites were influenced by previous day maritime emissions over the ocean, the terrestrial emissions over nearby urban areas, and by transported SO_2 from the north through both terrestrial and maritime areas. Overall maritime emissions contribute 10–70% of SO2 and 20–60% fine SO_4 on-shore and over the most terrestrial areas, with contributions decreasing with in-land distance from the coast. Maritime emissions also modify the photochemical environment, shifting O_3 production over coastal SC to more VOC-limited conditions. These suggest an important role for shipping emission controls in reducing fine particle and O_3 concentrations in SC

    4a-Methyl-2,3,4,4a-tetra­hydro-1H-carbazole-6-sulfonamide

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    In the title mol­ecule, C13H16N2O2S, the nine non-H atoms comprising the indole residue are approximately coplanar (r.m.s. deviation = 0.031 Å). The partially saturated ring adopts a chair conformation. One amine H forms an inter­molecular N—H⋯O hydrogen bond to a sulfonamide O atom, while the other amine H form is connected to the indole N atom of an adjacent mol­ecule via an N—H⋯N hydrogen bond, resulting in a three-dimensional architecture

    3-Amino-1-(4-meth­oxy­phen­yl)-9,10-dihydro­phenanthrene-2,4-dicarbonitrile

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    In the title compound, C23H17N3O, significant deviations from planarity are evidenced. This is quanti­fied in the dihedral angles formed between the central amino-benzene ring and the benzene rings of the meth­oxy­benzene [67.93 (8)°] and 1,2-dihydro­naphthalene [28.27 (8)°] residues. In the crystal the amino-H atoms form hydrogen bonds to the meth­oxy-O atom and to one of the cyano-N atoms to generate a two-dimensional array with a zigzag topology that stacks along the ( 1) plane

    MR-IMPACT II: Magnetic Resonance Imaging for Myocardial Perfusion Assessment in Coronary artery disease Trial: perfusion-cardiac magnetic resonance vs. single-photon emission computed tomography for the detection of coronary artery disease: a comparative multicentre, multivendor trial

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    Aims Perfusion-cardiac magnetic resonance (CMR) has emerged as a potential alternative to single-photon emission computed tomography (SPECT) to assess myocardial ischaemia non-invasively. The goal was to compare the diagnostic performance of perfusion-CMR and SPECT for the detection of coronary artery disease (CAD) using conventional X-ray coronary angiography (CXA) as the reference standard. Methods and results In this multivendor trial, 533 patients, eligible for CXA or SPECT, were enrolled in 33 centres (USA and Europe) with 515 patients receiving MR contrast medium. Single-photon emission computed tomography and CXA were performed within 4 weeks before or after CMR in all patients. The prevalence of CAD in the sample was 49%. Drop-out rates for CMR and SPECT were 5.6 and 3.7%, respectively (P = 0.21). The primary endpoint was non-inferiority of CMR vs. SPECT for both sensitivity and specificity for the detection of CAD. Readers were blinded vs. clinical data, CXA, and imaging results. As a secondary endpoint, the safety profile of the CMR examination was evaluated. For CMR and SPECT, the sensitivity scores were 0.67 and 0.59, respectively, with the lower confidence level for the difference of +0.02, indicating superiority of CMR over SPECT. The specificity scores for CMR and SPECT were 0.61 and 0.72, respectively (lower confidence level for the difference: −0.17), indicating inferiority of CMR vs. SPECT. No severe adverse events occurred in the 515 patients. Conclusion In this large multicentre, multivendor study, the sensitivity of perfusion-CMR to detect CAD was superior to SPECT, while its specificity was inferior to SPECT. Cardiac magnetic resonance is a safe alternative to SPECT to detect perfusion deficits in CA
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