15,139 research outputs found

    From “May Contain” to “Does Contain”: The price and trade effects of strict information requirements for GM maize under the Cartagena Protocol on Biosafety

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    Replaced with revised version of paper 07/22/10.Genetically modified food, International Trade, Cartagena Protocol on Biosafety., Agricultural and Food Policy, Environmental Economics and Policy, International Relations/Trade, Political Economy, Research and Development/Tech Change/Emerging Technologies, Q17, Q18, F18,

    In-Space technology experiments program. A high efficiency thermal interface (using condensation heat transfer) between a 2-phase fluid loop and heatpipe radiator: Experiment definition phase

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    Space Station elements and advanced military spacecraft will require rejection of tens of kilowatts of waste heat. Large space radiators and two-phase heat transport loops will be required. To minimize radiator size and weight, it is critical to minimize the temperature drop between the heat source and sink. Under an Air Force contract, a unique, high-performance heat exchanger is developed for coupling the radiator to the transport loop. Since fluid flow through the heat exchanger is driven by capillary forces which are easily dominated by gravity forces in ground testing, it is necessary to perform microgravity thermal testing to verify the design. This contract consists of an experiment definition phase leading to a preliminary design and cost estimate for a shuttle-based flight experiment of this heat exchanger design. This program will utilize modified hardware from a ground test program for the heat exchanger

    Infrared-temperature variability in a large agricultural field

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    The combined effect of water carved gullies, varying soil color, moisture state of the soil and crop, nonuniform phenology, and bare spots was measured for commercially grown barley planted on varying terrain. For all but the most rugged terrain, over 80% of the area within 4, 16, 65, and 259 ha cells was at temperatures within 3 C of the mean cell temperature. The result of using relatively small, 4 ha instantaneous field of views for remote sensing applications is that either the worst or the best of conditions is often observed. There appears to be no great advantage in utilizing a small instantaneous field of view instead of a large one for remote sensing of crop canopy temperatures. The two alternatives for design purposes are then either a very high spatial resolution, of the order of a meter or so, where the field is very accurately temperature mapped, or a low resolution, where the actual size seems to make little difference

    Calibration of Taut-Wire Apparatus

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    The undebated issue of justice: silent discourses in Dutch flood risk management

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    Flood risk for all types of flooding is projected to increase based on climate change projections and increases in damage potential. These challenges are likely to aggravate issues of justice in flood risk management (henceforth FRM). Based on a discursive-institutionalist perspective, this paper explores justice in Dutch FRM: how do institutions allocate the responsibilities and costs for FRM for different types of flooding? What are the underlying conceptions of justice? What are the future challenges with regard to climate change? The research revealed that a dichotomy is visible in the Dutch approach to FRM: despite an abundance of rules, regulations and resources spent, flood risk or its management, are only marginally discussed in terms of justice. Despite that the current institutional arrangement has material outcomes that treat particular groups of citizens differently, depending on the type of flooding they are prone to, area they live in (unembanked/embanked) or category of user (e.g. household, industry, farmer). The paper argues that the debate on justice will (re)emerge, since the differences in distributional outcomes are likely to become increasingly uneven as a result of increasing flood risk. The Netherlands should be prepared for this debate by generating the relevant facts and figures. An inclusive debate on the distribution of burdens of FRM could contribute to more effective and legitimate FRM

    Activity Dependent Branching Ratios in Stocks, Solar X-ray Flux, and the Bak-Tang-Wiesenfeld Sandpile Model

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    We define an activity dependent branching ratio that allows comparison of different time series XtX_{t}. The branching ratio bxb_x is defined as bx=E[ξx/x]b_x= E[\xi_x/x]. The random variable ξx\xi_x is the value of the next signal given that the previous one is equal to xx, so ξx={Xt+1Xt=x}\xi_x=\{X_{t+1}|X_t=x\}. If bx>1b_x>1, the process is on average supercritical when the signal is equal to xx, while if bx<1b_x<1, it is subcritical. For stock prices we find bx=1b_x=1 within statistical uncertainty, for all xx, consistent with an ``efficient market hypothesis''. For stock volumes, solar X-ray flux intensities, and the Bak-Tang-Wiesenfeld (BTW) sandpile model, bxb_x is supercritical for small values of activity and subcritical for the largest ones, indicating a tendency to return to a typical value. For stock volumes this tendency has an approximate power law behavior. For solar X-ray flux and the BTW model, there is a broad regime of activity where bx1b_x \simeq 1, which we interpret as an indicator of critical behavior. This is true despite different underlying probability distributions for XtX_t, and for ξx\xi_x. For the BTW model the distribution of ξx\xi_x is Gaussian, for xx sufficiently larger than one, and its variance grows linearly with xx. Hence, the activity in the BTW model obeys a central limit theorem when sampling over past histories. The broad region of activity where bxb_x is close to one disappears once bulk dissipation is introduced in the BTW model -- supporting our hypothesis that it is an indicator of criticality.Comment: 7 pages, 11 figure
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