1,672 research outputs found

    Crop Supply Response under Risk: Impacts of Emerging Issues on Southeastern U.S. Agriculture

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    In this paper we consider factors that affect both crop prices and yields in order to examine supply responses of major crops in the Southeast. Due to the variable nature of crop production in the Southeast, previous studies that ignore price and yield risk may fail to capture one of the salient features of the region’s agriculture. Our results indicate supply elasticity values for corn, cotton, and soybeans of approximately 0.670, 0.506, and 0.195, respectively. Compared with the results of studies in other regions, corn and cotton acres respond more to price changes and soybean acres respond less to price changes.acreage supply, crop supply response model, risk analysis, Southeast U.S. agriculture, Crop Production/Industries, Production Economics, Q12, Q13, Q16,

    Farmed foxes prefer a cage with an unobstructed View

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    We have observed earlier that farmed blue foxes (Alopex lagopus) and silver foxes (Vulpes vulpes) tend to avoid resting at those sites in their cages from which the view to the surroundings is obstmeted. In the present study this hypothesis wastested in a preference test in Which the foxes could choose between a cage with an unobstructed view and a cage with a partially obstructed view. Both blue foxes and silver foxes spent a smaller percentage of their daily active time in the cage with the obstructed view than in the cage with the unobstructed view. They almost exclusively preferred the cage with the unobstructed view as a resting site. Obstructed/unobstrueted View is a key feature of the cage environment that should be taken into consideration when designing housing systems for farmed foxes

    Feed intake, gastrointestinal system and body composition in reindeer calves fed early harvested first cut timothy silage (Phleum pratense)

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    Early harvested first cut (EFC) timothy silage was fed to five reindeer calves (Rangifer tarandus tarandus L.) taken from their natural summer pasture and brought to Tromsø for feeding trial. The calves were housed indoors in metabolism cages and fed EFC timothy silage ad lib. during the trial, which lasted from late November 1994 until the end of February 1995, when animals subsequently were slaughtered. Daily feed intake, gastrointestinal (GI) anatomy, body weight and body composition of the animals were examined. Timothy silage {Phleum praténse) was harvested 21 June, 1994 in Tromsø, prewilted and stored as round bales containing 97% leaves. The EFC silage contained 42.1% dry matter (DM), and 18.1% crude protein, 20.7% cellulose, 16.9% hemicellulose and 28.0% water soluble carbohydrates (WSC) of DM. Mean feed intake (DM) 24 hours after the trial started (day 1) was 9-4 g/kg body mass (BM) (S.D.+ 3-9), while the mean daily DM intake during days 15-74 comprised 24.2 g/kg BM (S.D.+ 6.1). All animals except one gained body weight during the trial. The median (range) BM at start and at slaughter was 48.5 kg (34.5¬58.0 kg) and 50.0 kg (42.0-53.5 kg), respectively. Median (range) carcass weight % of BM was 58.0% (51.2-58.7%) and muscle index value 0.0132 (0.0106-0.0176). The median reticulo-rumen (RR) content wet weight (WW) was 4601 g (range 2697-5000 g) comprising 9.3% of the BM, and 85.1% of the total gastrointestinal wet weight content. The median (range) gastrointestinal tract weight was 14.1% of BM (10.7-16.4%). Based on feed intake during the trial and body composition at slaughtet we conclude that first cut timothy silage is suitable as emergency feed to reindeer, as long as it is harvested in early growth stage with high proportion of leaves

    Self-assembled GaIn(N)As quantum dots: Enhanced luminescence at 1.3 µm

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    Self-assembled GaIn(N)As quantum dots are fabricated on GaAs by atmospheric pressuremetalorganic vapor-phase epitaxy using dimethylhydrazine (DMHy) precursor as a nitrogen source. The incorporation of nitrogen into the islands is observed to be negligible. However, the areal density of the islands is increased by up to one order of magnitude compared to that of the respective GaInAs islands. The GaIn(N)As island size can also be controlled by varying the DMHy flow. An enhancement of the room-temperature luminescence at 1.3 μm is observed in the GaIn(N)As samples grown with DMHy.Peer reviewe

    Experimental investigation towards a periodically pumped single-photon source

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    Experiments towards a periodically pumped single-photon source are presented. The lateral piezoelectric field of a surface acoustic wave dissociates laser-generated two-dimensional excitons into electrons and holes. These carriers are separated by the wave potential and are transported over macroscopic length scales without recombining. When reaching a stress-induced quantum dot in the quantum well they periodically populate the zero-dimensional states and recombine, emitting single photons periodically in time according to the surface acoustic-wave frequency. We have successfully reduced the number of pumped quantum dots down to 100 and have detected a strong blinking photoluminescence signal. By further reducing the number of quantum dots down to 1 a periodically pumped single photon source could be realized.Peer reviewe
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