405 research outputs found

    The All New This Old South

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    Recent claims concerning the rise of the Sunbelt closely resemble those previously made about the New South. It is assumed that the South has finally broken the ties of dependency with the North and has embarked on a remarkable path of self-sustained growth. In fact, this growth in the South is considered to be largely at the expense of the North. These and other similar claims are based on five assumptions about the South: 1) An economic transformation has occurred in the region; 2) absentee ownership is minimal; 3) benefits of economic growth has been diffused to most segments of the population; 4) economic growth has reduced poverty and inequality in the region; and 5) government spending has spurred much of the region\u27s growth. These assumptions form the basis of the diffusion model of economic-industrial development. Examining these assumptions in light of available data, however, places in question the validity of claims made about the Sunbelt

    Sensitivity of CSM-CERES-Maize model to soil available water and impact on rainfed maize grown in the Brazilian Cerrado.

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    The response of maize to variations in soil available water (AW) is a function of the interactions among plant, soil and weather conditions. We studied the sensitivity of a previously calibrated CSM-CERES-Maize model and the response of rainfed maize grain yield to soil AW. The study was conducted for conditions in southeast Brazil. The model was set for weekly sowings, from August to September, for a total of 52 sowing dates. At each sowing date, six scenarios of soil AW using field capacity estimated at -4 kPa, -6 kPa, -10 kPa, -20 kPa, -33 kPa and determined in situ, were used. For each sowing date, the model was also set for rainfall reductions of 10%, 20%, 30%, 40% and 50%. The simulated results showed the sensitivity of the model to soil AW, which in turn affected grain yield of maize among sowing dates. For the highest yielding sowing date, a reduction of 48.3% in average grain yield was simulated with soil AW using FC at -4 kPa and FC at -33 kPa. Additionally, our simulations indicated significant correlation between grain yield and total crop evapotranspiration and between grain yield and maximum leaf area index. Scenarios of low rainfall had little effect on yield with high soil AW. Therefore, our simulations indicate that accurate information on FC is needed for the simulation of maize grown under rainfed conditions. Our simulations also indicate that the best sowing window for maize in southeastern Brazil ranges from Oct 17 to Nov 28

    Impact of climate change on maize grown in the brazilian cerrado.

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    Crops are subject to instabilities of climatic conditions that affect yield. Maize is very sensitive to factors like temperature, solar radiation and rainfall. The objective of this work was to evaluate, using crop growth models, the effects of climate change on maize grain yield produced under rainfed conditions. Two global circulation models, HadGEM2-ES and MIROC5, coupled to the regional model Eta, were used to generate projections of changes in maximum and minimum air temperature, solar radiation and rainfall for conditions in southeastern Brazil. The CSM-CERES-Maize model was then used to evaluate the effect of climate changes on rainfed maize grain yield. For each combination of global and regional circulation models, two greenhouse gas concentration scenarios were used: RCP4.5 and RCP8.5. The combined use of global circulation and crop growth models allowed us to estimate the expected average grain yield of corn as affected by future climate. The simulated results indicated that, even at best sowing dates, considerable reduction in maize grain yield may occur. Our simulated results also indicated that the largest grain yield reductions may occur for future climate scenarios from 2071 to the end of the 21st century

    Design, Fabrication, and Experimental Demonstration of Junction Surface Ion Traps

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    We present the design, fabrication, and experimental implementation of surface ion traps with Y-shaped junctions. The traps are designed to minimize the pseudopotential variations in the junction region at the symmetric intersection of three linear segments. We experimentally demonstrate robust linear and junction shuttling with greater than one million round-trip shuttles without ion loss. By minimizing the direct line of sight between trapped ions and dielectric surfaces, negligible day-to-day and trap-to-trap variations are observed. In addition to high-fidelity single-ion shuttling, multiple-ion chains survive splitting, ion-position swapping, and recombining routines. The development of two-dimensional trapping structures is an important milestone for ion-trap quantum computing and quantum simulations.Comment: 9 pages, 6 figure
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