52,205 research outputs found

    The use of Kodak aerochrome infrared color film, type 2443, as a remote sensing tool

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    An infrared color film, Kodak Aerochrome, type 2443, has replaced the 8443 film. The 2443 has lower contrast than the 8443 film, and allows deeper probing into areas that appear as solid black shadows on the 8443 film. The cyan layer of 2443 is approximately 1 1/2 stops slower, at a density of 1.4, than the yellow and magenta emulsion layers

    Effects of organic and ‘low input’ production methods on food quality and safety

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    The intensification of agricultural production in the last century has resulted in a significant loss of biodiversity, environmental problems and associated societal costs. The use of shorter rotations or monocropping and high levels of mineral fertilisers, pesticides and crop growth regulators may also have had negative impacts on food quality and safety. To reverse the negative environmental and biodiversity impacts of agricultural intensification, a range of different ‘low input’ farming systems have been developed and are now supported by EU and government support schemes. A range of recent reviews concluded that switching to low input, integrated or organic farming practices results in significant environmental benefits and increased biodiversity in agro-ecosystems. Some recent studies also reported higher levels of nutritionally desirable compounds (e.g. vitamins, antioxidants, mineral nutrients) in foods from organic and ‘low input’ production systems compared to food from conventional systems. The increasing demand and current price premiums achieved by foods from low input and especially organic production systems were shown to be closely linked to consumer perceptions about nutritional and health benefits of such foods. However, there are other studies reporting no significant differences in composition between low input and conventional foods, or inconsistent results. There is currently a lack of (a) factorial studies, which allow the effect of individual production system components (e.g. rotation design, fertility management, crop health management, variety choice) on food composition to be assessed and (b) dietary intervention or cohort studies which compare the effect of consuming foods from different production systems on animal and/or human health. It is therefore currently not possible to draw overall conclusions about the effect of low input production on food quality and safety. This paper will (a) describe the range of organic and other ‘low input’ standards, certification and support systems currently used, (b) summarise the currently available information on effects of organic and other low input crop production systems on the environment, biodiversity and food quality, and (c) describe the methodologies and results from subproject 2 of the EU-funded Integrated project QualityLowInputFood. This project focused on improving our knowledge about the effect of organic and low input crop and livestock production systems on food quality and safety parameters

    Stable Topological Superfluid Phase of Ultracold Polar Fermionic Molecules

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    We show that single-component fermionic polar molecules confined to a 2D geometry and dressed by a microwave field, may acquire an attractive 1/r31/r^3 dipole-dipole interaction leading to superfluid p-wave pairing at sufficiently low temperatures even in the BCS regime. The emerging state is the topological px+ipyp_x+ip_y phase promising for topologically protected quantum information processing. The main decay channel is via collisional transitions to dressed states with lower energies and is rather slow, setting a lifetime of the order of seconds at 2D densities 108\sim 10^8 cm2^{-2}

    Locating the pseudogap closing point in cuprate superconductors: absence of entrant or reentrant behavior

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    Current descriptions of the pseudogap in underdoped cuprates envision a doping-dependent transition line T(p)T^*(p) which descends monotonically towards zero just beyond optimal doping. There is much debate as to the location of the terminal point pp^* where T(p)T^*(p) vanishes, whether or not there is a phase transition at TT^* and exactly how T(p)T^*(p) behaves below TcT_c within the superconducting dome. One perspective sees T(p)T^*(p) cutting the dome and continuing to descend monotonically to zero at pcrit0.19p_{crit} \approx 0.19 holes/Cu - referred to here as `entrant behavior'. Another perspective derived from photoemission studies is that T(p)T^*(p) intersects the dome near pcrit0.23p_{crit} \approx 0.23 holes/Cu then turns back below TcT_c, falling to zero again around pcrit0.19p_{crit} \approx 0.19 - referred to here as `reentrant behavior'. By examining thermodynamic data for Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta} we show that neither entrant nor reentrant behavior is experimentally supported. Rather, pcrit0.19p_{crit} \approx 0.19 sharply delimits the pseudogap regime and for p<0.19p < 0.19 the pseudogap is always present, independent of temperature. Similar results are found for Y0.8_{0.8}Ca0.2_{0.2}Ba2_2Cu3_3O7δ_{7-\delta}. For both materials T(p)T^*(p) is not a temperature but a crossover scale, E(p)/2kB\approx E^*(p)/2k_B, reflecting instead the underlying pseudogap energy E(p)E^*(p) which vanishes as p0.19p \rightarrow 0.19.Comment: 20 Pages, 9 Figures, in press Phys. Rev.

    A proposed test of the Einstein theory of gravitation by means of an unshielded orbiting gyro using passive telemetry

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    Proposed test of theory of gravitation by an unshielded earth orbiting gyroscope using passive telemetr
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