836 research outputs found

    Mitigation of salt stress in Indian mustard (Brassica juncea L.) by the application of triacontanol and hydrogen sulfide

    Get PDF
    Salinity stress is a well-known abiotic stress that has been shown to have a negative impact on crop growth, production, and soil richness. The current study was intended to ameliorate salt stress in Indian mustard (Brassica juncea L.), keeping in mind the detrimental influence of salt stress. A pot experimentation was executed on B. juncea to examine the efficacy of exogenous application of triacontanol (TRIA) and hydrogen sulfide (H2S) (NaHS donor), either alone or in combination, on growth attributes, metabolites, and antioxidant defense system exposed to salt stress at three distinct concentrations (50, 100 and 150 mM NaCl). Increase in the concentration of oxidative markers (malondialdehyde and hydrogen peroxide) was found which results in inhibited growth of B. juncea. The growth characteristics of plant, such as root and shoot length, fresh and dry weight under salt stress, were improved by foliar application of TRIA (150 ”M) and H2S (25 ”M) alone as well as in combination. Additionally, salt stress reduced the levels of protein, metabolites (flavonoids, phenolic and anthocyanin), antioxidant enzyme activity including that of ascorbate peroxidase, catalase, polyphenol oxidase and guaiacol peroxidase as well as the level of ascorbic acid and glutathione (non-enzymatic antioxidants). However, application of TRIA and H2S alone or in grouping substantially raised the content of protein, metabolites and antioxidant defense system in plants of B. juncea

    How Do Long Term Crop Rotations Influence Weed Populations: Exploring the Impacts of More than 50 Years of Crop Management in Serbia

    Get PDF
    Crop rotation is known as an eco-friendlier approach, as provides diversification in crop management systems, modifies intensive pressure on the agricultural ecosystem, utilizes various soil horizons, and prevents the establishment of specific pests and weeds. We set out here a study on the farms that have been managed over 50 years of specific continuous crop management programs. The experimental treatments were in a different management system: monoculture of maize, winter wheat, and soybean, 2-year crop rotation (winter wheat–maize) with and without chemical fertilizer, and 3-year crop rotation (winter wheat–soybean–maize) with and without chemical fertilizer and manure. We took soil samples six times from 2014 to 2017 prior to sowing and after harvesting each year. Weed seeds were extracted from soils and identified and counted by species. We, upon the data of a long term experiment of crop rotation, could conclude that crop rotations with more crops in the sequence are significantly effective in maintaining weed populations, a low-input crop production could reach a constant low population below an important damaging density, and therefore will be a more sustainable crop production while chemical fertilizers would change the soil’s chemical and structure and imbalance the plant population diversity and manures with high weed seed infestations have the potential to totally eradicate crop rotation effects, Therefore, clean manures or compost are highly recommended

    Effects of ramped wall temperature and concentration on viscoelastic Jeffrey’s fluid flows from a vertical permeable cone

    Get PDF
    In thermo-fluid dynamics, free convection flows external to different geometries such as cylinders, ellipses, spheres, curved walls, wavy plates, cones etc. play major role in various industrial and process engineering systems. The thermal buoyancy force associated with natural convection flows can exert a critical role in determining skin friction and heat transfer rates at the boundary. In thermal engineering, natural convection flows from cones has gained exceptional interest. A theoretical analysis is developed to investigate the nonlinear, steady-state, laminar, non-isothermal convection boundary layer flows of viscoelastic fluid from a vertical permeable cone with a power-law variation in both temperature and concentration. The Jeffery’s viscoelastic model simulates the non-Newtonian characteristics of polymers, which constitutes the novelty of the present work. The transformed conservation equations for linear momentum, energy and concentration are solved numerically under physically viable boundary conditions using the finite-differences Keller-Box scheme. The impact of Deborah number (De), ratio of relaxation to retardation time (λ), surface suction/injection parameter (fw), power-law exponent (n), buoyancy ratio parameter (N) and dimensionless tangential coordinate (Ńź) on velocity, surface temperature, concentration, local skin friction, heat transfer rate and mass transfer rate in the boundary layer regime are presented graphically. It is observed that increasing values of De reduces velocity whereas the temperature and concentration are increased slightly. Increasing λ enhance velocity however reduces temperature and concentration slightly. The heat and mass transfer rate are found to decrease with increasing De and increase with increasing values of λ. The skin friction is found to decrease with a rise in De whereas it is elevated with increasing values of λ. Increasing values of fw and n, decelerates the flow and also cools the boundary layer i.e. reduces temperature and also concentration. The study is relevant to chemical engineering systems, solvent and polymeric processes

    Consensus-based technical recommendations for clinical translation of renal ASL MRI

    Get PDF
    OBJECTIVES: This study aimed at developing technical recommendations for the acquisition, processing and analysis of renal ASL data in the human kidney at 1.5 T and 3 T field strengths that can promote standardization of renal perfusion measurements and facilitate the comparability of results across scanners and in multi-centre clinical studies. METHODS: An international panel of 23 renal ASL experts followed a modified Delphi process, including on-line surveys and two in-person meetings, to formulate a series of consensus statements regarding patient preparation, hardware, acquisition protocol, analysis steps and data reporting. RESULTS: Fifty-nine statements achieved consensus, while agreement could not be reached on two statements related to patient preparation. As a default protocol, the panel recommends pseudo-continuous (PCASL) or flow-sensitive alternating inversion recovery (FAIR) labelling with a single-slice spin-echo EPI readout with background suppression and a simple but robust quantification model. DISCUSSION: This approach is considered robust and reproducible and can provide renal perfusion images of adequate quality and SNR for most applications. If extended kidney coverage is desirable, a 2D multislice readout is recommended. These recommendations are based on current available evidence and expert opinion. Nonetheless they are expected to be updated as more data become available, since the renal ASL literature is rapidly expanding

    Utilisation of an operative difficulty grading scale for laparoscopic cholecystectomy

    Get PDF
    Background A reliable system for grading operative difficulty of laparoscopic cholecystectomy would standardise description of findings and reporting of outcomes. The aim of this study was to validate a difficulty grading system (Nassar scale), testing its applicability and consistency in two large prospective datasets. Methods Patient and disease-related variables and 30-day outcomes were identified in two prospective cholecystectomy databases: the multi-centre prospective cohort of 8820 patients from the recent CholeS Study and the single-surgeon series containing 4089 patients. Operative data and patient outcomes were correlated with Nassar operative difficultly scale, using Kendall’s tau for dichotomous variables, or Jonckheere–Terpstra tests for continuous variables. A ROC curve analysis was performed, to quantify the predictive accuracy of the scale for each outcome, with continuous outcomes dichotomised, prior to analysis. Results A higher operative difficulty grade was consistently associated with worse outcomes for the patients in both the reference and CholeS cohorts. The median length of stay increased from 0 to 4 days, and the 30-day complication rate from 7.6 to 24.4% as the difficulty grade increased from 1 to 4/5 (both p < 0.001). In the CholeS cohort, a higher difficulty grade was found to be most strongly associated with conversion to open and 30-day mortality (AUROC = 0.903, 0.822, respectively). On multivariable analysis, the Nassar operative difficultly scale was found to be a significant independent predictor of operative duration, conversion to open surgery, 30-day complications and 30-day reintervention (all p < 0.001). Conclusion We have shown that an operative difficulty scale can standardise the description of operative findings by multiple grades of surgeons to facilitate audit, training assessment and research. It provides a tool for reporting operative findings, disease severity and technical difficulty and can be utilised in future research to reliably compare outcomes according to case mix and intra-operative difficulty
    • 

    corecore