3,639 research outputs found

    Vorlesungen ĂŒber Physik der AtmosphĂ€re

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    An evolutionary economic perspective on technical change and adjustment in cane harvesting systems in the Australian sugar industry

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    Australian sugar-producing regions have differed in terms of the extent and rate of incorporation of new technology into harvesting systems. The Mackay sugar industry has lagged behind most other sugar-producing regions in this regard. The reasons for this are addressed by invoking an evolutionary economics perspective. The development of harvesting systems, and the role of technology in shaping them, is mapped and interpreted using the concept of path dependency. Key events in the evolution of harvesting systems are identified, which show how the past has shaped the regional development of harvesting systems. From an evolutionary economics perspective, the outcomes observed are the end result of a specific history.Crop Production/Industries,

    Success Strategies Being Implemented in Fresh Milk Supply Chains

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    Deregulation of the Australian dairy industry, and ensuing supermarket strategies are transforming the fresh milk supply chains. Factors such as increasing consumer awareness, concerns about food safety and environment, innovation, supply chain integration and rationalisation of supply base are adding momentum to this transformation. Milk processors in response to changing market expectations are getting proactive in their relationship with retailers across all aspects of business, innovating to generate sufficient returns from proprietary brands and strategically orienting themselves to develop a mixed customer portfolio and appropriate management structures to service that portfolio. Milk producers are expanding businesses to achieve production and cost efficiencies and strengthening contractual relationships on input and output side for a greater security.Livestock Production/Industries,

    Decision Support Systems in Australian Agriculture: State of the Art and Future Development

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    This paper reports and discusses the results of a survey conducted with experts working in the field of decision support systems (DSS) in Australian agriculture. It also reviews the literature on DSS in the light of these experts' responses. The findings from this survey have consolidated our understanding of the current state of DSS in Australian agriculture. The uptake of DSS by farmers has been slow and various issues said to be contributing to this include fear of using computers, time constraints, poor marketing, complexity, lack of local relevance, lack of end-user involvement, and mismatched objectives between developers and users. The future prospect for the development of DSS was generally regarded to be poor. Never-the-less, the authors believe that new DSS which embrace the suggested criteria could be widely accepted by farmers. These criteria mean that to be widely used by farmers, any successful DSS needs to address widespread problems: they need to be location specific, and gain strong support from initial users. They also need to be simple to use, relevant, effective, low cost, and user friendly and it is most likely that farmers would have been involved in their development. We believe that farmers' personalities, and their attitudes towards risk management and decision making, will influence the pattern of adoption of DSS in Australian agriculture while the intergenerational change that is occurring in the management of Australian farms is a positive factor that may encourage more widespread use of these tools.DSS, farmers' decision-making, expert opinion, management decisions, Farm Management, D7, D8, Q12, Q13, Q16,

    Metamaterial metal-based bolometers

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    We demonstrate metamaterial metal-based bolometers, which take advantage of resonant absorption in that a spectral and/or polarization filter can be built into the bolometer. Our proof-of-principle gold-nanostructure-based devices operate around 1.5 \mum wavelength and exhibit room-temperature time constants of about 134 \mus. The ultimate detectivity is limited by Johnson noise, enabling room-temperature detection of 1 nW light levels within 1 Hz bandwidth. Graded bolometer arrays might allow for integrated spectrometers with several octaves bandwidth without the need for gratings or prisms and for integrated polarization analysis without external polarization optics

    Coherent control of atomic excitation using off-resonant strong few-cycle pulses

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    We study the dynamics of a two-level system driven by an off-resonant few-cycle pulse which has a phase jump ϕ\phi at t=t0t=t_{0}, in contrast to many cycle pulses, under non rotating-wave approximation (NRWA). We give a closed form analytical solution for the evolution of the probability amplitude ∣Ca(t)∣|C_{a} (t)| for the upper level. Using the appropriate pulse parameters like phase-jump ϕ\phi, jump time t0t_{0}, pulse width τ\tau, frequency Îœ\nu and Rabi frequency Ω0\Omega_{0} the population transfer, after the pulse is gone, can be optimized and for the pulse considered here, enhancement of 106−10810^{6}-10^{8} factor was obtained.Comment: 5 Pages, 7 Figure

    Discovery of Multiple Modified F-430 Coenzymes in Methanogens and Anaerobic Methanotrophic Archaea Suggests Possible New Roles for F-430 in Nature

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    Methane is a potent greenhouse gas that is generated and consumed in anaerobic environments through the energy metabolism of methanogens and anaerobic methanotrophic archaea (ANME), respectively. Coenzyme F-430 is essential for methanogenesis, and a structural variant of F-430, 17(2)-methylthio-F-430 (F-430-2), is found in ANME and is presumably essential for the anaerobic oxidation of methane. Here we use liquid chromatography-high-resolution mass spectrometry to identify several new structural variants of F-430 in the cell extracts of selected methanogens and ANME. Methanocaldococcus jannaschii and Methanococcus maripaludis contain an F-430 variant (denoted F-430-3) that has an M+ of 1,009.2781. This mass increase of 103.9913 over that of F-430 corresponds to C3H4O2S and is consistent with the addition of a 3-mercaptopropionate moiety bound as a thioether followed by a cyclization. The UV absorbance spectrum of F-430-3 was different from that of F-430 and instead matched that of an F-430 derivative where the 17(3) keto moiety had been reduced. This is the first report of a modified F-430 in methanogens. In a search for F-430-2 and F-430-3 in other methanogens and ANME, we have identified a total of nine modified F-430 structures. One of these compounds may be an abiotic oxidative product of F-430, but the others represent naturally modified versions of F-430. This work indicates that F-430-related molecules have additional functions in nature and will inspire further research to determine the biochemical role(s) of these variants and the pathways involved in their biosynthesis
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