Response of Corn and Palmer amaranth to Mesotrione

Mesotrione is a herbicide used for the selective pre- and post-emergence control of a wide range of broadleaf and grass weeds in corn (Zea mays). It inhibits the enzyme 4-hydroxyphenylpyruvate dioxygenase (HPPD) which leads to stop biosynthesis of plastoquinone, a key factor in the synthesis of carotenoid pigment. The depletion of carotenoids leading to bleaching symptoms followed by necrosis in sensitive plants. Palmer amaranth (Amaranth Palmeri) is one of the major weeds in corn production system. This study was conducted to test the hypothesis that mesotrione may be effective to control Palmer amaranth and safe for use in corn. Therefore, the objective of this research was to evaluate response of corn and Palmer amaranth to mesotrione. Corn and Palmer amaranth plants were treated with mesotrione at 105 g ai ha-1,and plant survival data was collected at 3 week after application. There was no injury reported to any of the corn plant, and plant survival rate was reported 100%. However, Palmer amaranth plants showed bleaching symptoms followed by necrosis and plant death. Only 12.5% Palmer amaranth plants survived after mesotrione application. These results demonstrated the tolerance of corn and sensitivity of Palmer amaranth to mesotrione

A stress free model for residual stress assessment using thermoelastic stress analysis

Thermoelastic Stress Analysis (TSA) has been proposed as a method of obtaining residual stresses. The results of a preliminary study demonstrated that when Al-2024 plate containing holes that were plastically deformed by cold expansion process to 2% and 4% strain the thermoelastic response in the material around the hole was different to that obtained from a plate that had not experienced any plastic cold expansion (i.e. a reference specimen). This observation provides an opportunity for obtaining residual stresses based on TSA data. In many applications a reference specimen (i.e. residual stress free specimen) may not be available for comparison, so a synthetic, digital bitmap has been proposed as an alternative. An elastic finite element model is created using commercially available software Abaqus/Standard and the resultant stress field is extracted. The simulated stress field from the model is mapped onto a grid that matches the TSA pixel data from a physical reference specimen. This stress field is then converted to a ?T/T field that can be compared to the full-field TSA data. When the reference experimental data is subtracted from the, bitmap dataset the resultant ?T/T field is approximately zero. Further work proposes replacing the experimental reference data with that from specimens that have undergone cold expansion with the aim of revealing the regions affected by residual stress through a departure from zero in the resultant stress field. The paper demonstrates the first steps necessary for deriving the residual stresses from a general specimen using TSA

Environmental impact and embodied energy

Recent reports from the industry suggest that FRP has been the most cost effective solution at “first installed” cost in a few recent structures. Even if the “first installed’ cost of FRP solutions in not favourable compared to equivalent concrete/steel structures the life cycle cost and life cycle assessment analyses could be used to demonstrate cost and sustainability benefits of FRP structures. For instance, FRP bridge decks have advantages, such as controlled off-site fabrication, high strength, highfatigue and corrosion resistance, light weight, easy transportation, faster on-site assembly, minimisation of traffic disturbances,etc.; these could be used to off-set the initial cost, and to exploit the sustainable solutions offered by FRP materials

A survey of mindset theories of intelligence and medical error self-reporting among pediatric housestaff and faculty

Référence bibliographique : Rol, 107037Appartient à l’ensemble documentaire : Pho20RolImage de press

Does Having a Female Sarpanch Promote Service Delivery for Women and Democratic Participation of Women? Evidence from Maharashtra, India

In this paper we examine the impact of mandated reservations for female sarpanchs in the gram panchayats on perceptions of service delivery and women's democratic participation. Using survey data from the Sangli district, Maharashtra, we find that the availability of basic, public services is significantly higher in female sarpanch villages as compared to the male sarpanch villages, when the elections have been held three to 3 1/2 years before the survey; while service delivery in villages with more recently elected female sarpanchs is worse. Further, the reservations have a significant, positive impact on the democratic participation of the women in the female sarpanch villages, again driven by the impact of female sarpanchs elected 3 ½ years before the survey. The democratic participation of women, in turn, affects the availability of services very robustly. The findings suggest that the positive effects in terms of service delivery and democratic participation will take some time to materialize

Experimental and numerical investigation of float glass–GFRP hybrid beams

Despite the great potentials of glass as a construction material, its brittle material behaviour poses major challenges to structural engineers when designing load-bearing glass structural members. This paper presents the load response and the failure behaviour of float glass–GFRP hybrid beams, when used as a mean of improving strength and ductility of float glass. Hybrid beams made from two layers of float glass sheets and an adhesively-bonded semi-transparent pre-cured GFRP interlayer were tested in four-point bending. The experimental results showed that double layer hybrid beams continued to take load even after the formation of the first major crack, and the beams were stronger and ductile than conventional single and multilayer float glass beams. Once the bottom glass layer has cracked the combination of the GFRP and the top glass layer carried the applied load whilst the gradual decrease in the stiffness due to the formation of new cracks ensures a ductile failure. Experimentally-validated finite element (FE) models that predict the evolution of stresses, stiffness and failure load of single and double layer glass beams, and glass– GFRP hybrid beams are also presented

Development of TNB distribution network risk based asset replacement policy and guideline for medium voltage primary equipment

Asset Management (AM) is the systematic and coordinated activity of an organization to realize value from assets, through which an organization optimally and sustainably manages its assets and asset systems, their associated performance, risk and expenditures over their life cycle for the purpose of achieving its organizational strategic plan. An effective AM System enables TNB Distribution to establish and verify a holistic view of asset management throughout an asset’s whole life. It facilitates an optimal mixture of capital, operations, maintenance, resourcing, risks, performance and sustainability within a framework of good governance

Physiological and Molecular Characterization of Hydroxyphenylpyruvate Dioxygenase (HPPD)-inhibitor Resistance in Palmer Amaranth (Amaranthus palmeri S. Wats.)

Citation: Nakka, S., Godar, A. S., Wani, P. S., Thompson, C. R., Peterson, D. E., Roelofs, J., & Jugulam, M. (2017). Physiological and Molecular Characterization of Hydroxyphenylpyruvate Dioxygenase (HPPD)-inhibitor Resistance in Palmer Amaranth (Amaranthus palmeri S. Wats.). Frontiers in Plant Science, 8, 12. doi:10.3389/fpls.2017.00555Herbicides that inhibit hydroxyphenylpyruvate dioxygenase (HPPD) such as mesotrione are widely used to control a broad spectrum of weeds in agriculture. Amaranthus palmeri is an economically troublesome weed throughout the United States. The first case of evolution of resistance to HPPD-inhibiting herbicides in A. palmeri was documented in Kansas (KS) and later in Nebraska (NE). The objective of this study was to investigate the mechansim of HPPD-inhibitor (mesotrione) resistance in A. palmeri. Dose response analysis revealed that this population (KSR) was 10-18 times more resistant than their sensitive counterparts (MSS or KSS). Absorbtion and translocation analysis of [C-14] mesotrione suggested that these mechanisms were not involved in the resistance in A. palmeri. Importantly, mesotrione (>90%) was detoxified markedly faster in the resistant populations (KSR and NER), within 24 hours after treatment (HAT) compared to sensitive plants (MSS, KSS, or NER). However, at 48 HAT all populations metabolized the mesotrione, suggesting additional factors may contribute to this resistance. Further evaluation of mesotrione-resistant A. palmeri did not reveal any specific resistance-conferring mutations nor amplification of HPPD gene, the molecular target of mesotrione. However, the resistant populations showed 4- to 12-fold increase in HPPD gene expression. This increase in HPPD transcript levels was accompanied by increased HPPD protein expression. The significant aspects of this research include: the mesotrione resistance in A. palmeri is conferred primarily by rapid detoxification (non-target-site based) of mesotrione; additionally, increased HPPD gene expression (target-site based) also contributes to the resistance mechanism in the evolution of herbicide resistance in this naturally occurring weed species