2,225 research outputs found

    A Prototype Selection Committee Decision Analysis and Support System, SCDAS: Theoretical Background and Computer Implementation

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    One of the important problems in decision analysis related to the situation, where the committee (group of decision makers) has to select the best alternative from a given, finite set. In the most cases, the alternatives are evaluated on the basis of several quality factors. In the paper, the authors present the new approach, based on the principle of satisfactory decision making. This approach ensures proper structuralization of the decision process and allows proper balance of opinion of the group member. The experimental decision support system SCDAS was developed to test this approach

    The Formation of Fragments at Corotation in Isothermal Protoplanetary Disks

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    Numerical hydrodynamics simulations have established that disks which are evolved under the condition of local isothermality will fragment into small dense clumps due to gravitational instabilities when the Toomre stability parameter QQ is sufficiently low. Because fragmentation through disk instability has been suggested as a gas giant planet formation mechanism, it is important to understand the physics underlying this process as thoroughly as possible. In this paper, we offer analytic arguments for why, at low QQ, fragments are most likely to form first at the corotation radii of growing spiral modes, and we support these arguments with results from 3D hydrodynamics simulations.Comment: 21 pages, 1 figur

    Insecticide Efficacy Against Trimen’s False Tiger Moth, Agoma trimenii (Lepidoptera: Agaristidae)

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    Trimen’s false tiger moth, Agoma trimenii (Lepidoptera: Agaristidae), has developed pest status in vineyardsin the Northern Cape and Groblersdal areas of South Africa, and an integrated pest management system isrequired. The objective of this study was to test the susceptibility of A. trimenii larvae to three commercialproducts (Delegate®WG, Steward®150 EC and three doses of DiPel® DF). Bioassay tests using all threeproducts, and semi-field trials to test the potential of DiPel® DF against A. trimenii larvae, applied at differentwater volumes (50 g/1 000 L/ha and 50 g/1 430 L/ha) were performed. The residual activity of DiPel® DF,when applied at different water volumes, was investigated daily. Delegate® WG, Steward®150 EC and therecommended dose of DiPel® DF showed 100% larval mortality within seven days. Delegate® WG and therecommended dose of DiPel® DF proved to be the fastest acting products. The product label recommendeddose of DiPel® DF (0.25 g/500 mL distilled water) proved the most effective dose (in comparison to halvedand doubled dosages) and showed 100% mortality five days after application. Increasing the water volumeper ha of a spray application of DiPel® DF for the same application area, showed no significant increasein larval mortality. A reduction in insecticidal activity for DiPel® DF applied at both water volumes wasseen between leaves picked four days after spraying and leaves picked five days after spraying, and nomortality was observed after day 6. To help improve efficacy, attention should be given to increasing spraycoverage and residual activity of DiPel® DF, as well as using all tested products within an integrated pestmanagement system

    A Review of Trimen’s False Tiger Moth, Agoma trimenii (Lepidoptera: Agaristidae): Seasonal Biology, Potential Monitoring and Control Techniques

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    Trimen’s false tiger moth, Agoma trimenii (Lepidoptera: Agaristidae), has recently been found to occur in vineyards in the Northern Cape and Limpopo (Groblersdal area) provinces of South Africa. As little is known about the biology and behaviour of the moth, no official monitoring methods or economic thresholds relating to it, exist. Consequently, management and registered control options still require development. The first aim in the current review, was to gather and critically discuss all the available information on A. trimenii in the context of the information gained from field observations conducted in the Northern Cape, South Africa, during the 2016/2017 and 2017/2018 seasons. The paper also includes reporting on field observations made with regard to various aspects of the seasonal life cycle and ecology of A. trimenii, with a view to investigate, in future research, the potential biological control options available. Potential monitoring strategies of A. trimenii in the field were investigated. Various life stages of A. trimenii were identified, peak flight times were established, overlapping generations were determined, and the behavioural traits of all life stages were documented. Ultraviolet blue light traps proved to be the most promising potential monitoring strategy, with the prospect for an A. trimenii pheromone lure holding potential as an alternative monitoring strategy in future. With summarising all current information on A. trimenii, recommendations for growers to monitor and control A. trimenii are presented, towards the development of an integrated pest management system for the moth

    Mid-Miocene cooling and the extinction of tundra in continental Antarctica

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    A major obstacle in understanding the evolution of Cenozoic climate has been the lack of well dated terrestrial evidence from high-latitude, glaciated regions. Here, we report the discovery of exceptionally well preserved fossils of lacustrine and terrestrial organisms from the McMurdo Dry Valleys sector of the Transantarctic Mountains for which we have established a precise radiometric chronology. The fossils, which include diatoms, palynomorphs, mosses, ostracodes, and insects, represent the last vestige of a tundra community that inhabited the mountains before stepped cooling that first brought a full polar climate to Antarctica. Paleoecological analyses, 40Ar/39Ar analyses of associated ash fall, and climate inferences from glaciological modeling together suggest that mean summer temperatures in the region cooled by at least 8°C between 14.07 ± 0.05 Ma and 13.85 ± 0.03 Ma. These results provide novel constraints for the timing and amplitude of middle-Miocene cooling in Antarctica and reveal the ecological legacy of this global climate transition

    Quantum Parrondo's Games

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    Parrondo's Paradox arises when two losing games are combined to produce a winning one. A history dependent quantum Parrondo game is studied where the rotation operators that represent the toss of a classical biased coin are replaced by general SU(2) operators to transform the game into the quantum domain. In the initial state, a superposition of qubits can be used to couple the games and produce interference leading to quite different payoffs to those in the classical case.Comment: LateX, 10 pages, 2 figures, submitted to Physica A special issue (Gene Stanley Conference, Sicily, 2001), v2 minor correction to equations, v3 corrections to results section and table, acknowledgement adde

    Accelerating the open research agenda to solve global challenges

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    Harnessing science-based policy is key to addressing global challenges like the biodiversity and climate crises. Open research principles underpin effective science-based policy, but the uptake of these principles is likely constrained by the politicisation, commoditisation and conflicting motives of stakeholders in the research landscape. Here, using the mission and vision statements from 129 stakeholders from across the research landscape, we explore alignment in open research principles between stakeholders. We find poor alignment between stakeholders, largely focussed around journals, societies and funders, all of which have low open research language-use. We argue that this poor alignment stifles knowledge flow within the research landscape, ultimately limiting the mobilisation of impactful science-based policy. We offer recommendations on how the research landscape could embrace open research principles to accelerate societies' ability to solve global challenges

    Nuclear structure corrections to gyromagnetic factor of the bound lepton

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    In the framework of the quasipotential method the covariant expression for the two-particle vertex operator is obtained. The nuclear structure corrections of orders (Z\alpha)^4, (Z\alpha)^5 including recoil effects to gyromagnetic factors of the bound electron and muon are calculated. Numerical value of the contribution of order (Z\alpha)^5 is obtained by means of the dipole parameterization for the nuclear charge form factor in the range of the nuclear charges Z=7-32.Comment: Talk presented on poster session of the Bogolubov Conference "Problems of Theoretical and Mathematical Physics", Moscow-Dubna, September 2-6, 2004, 14 pages, 2 figure

    Quantum games of asymmetric information

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    We investigate quantum games in which the information is asymmetrically distributed among the players, and find the possibility of the quantum game outperforming its classical counterpart depends strongly on not only the entanglement, but also the informational asymmetry. What is more interesting, when the information distribution is asymmetric, the contradictive impact of the quantum entanglement on the profits is observed, which is not reported in quantum games of symmetric information.Comment: 5 pages, 3 figure
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