Emission spectrum of a dressed exciton-biexciton complex in a semiconductor quantum dot

The photoluminescence spectrum of a single quantum dot was recorded as a secondary resonant laser optically dressed either the vacuum-to-exciton or the exciton-to-biexciton transitions. High-resolution polarization-resolved measurements using a scanning Fabry-Perot interferometer reveal splittings of the linearly-polarized fine-structure states that are non-degenerate in an asymmetric quantum dot. These splittings manifest as either triplets or doublets and depend sensitively on laser intensity and detuning. Our approach realizes complete resonant control of a multi-excitonic system in emission, which can be either pulsed or continuous-wave, and offers direct access to the emitted photons.Comment: 4 pages, 4 figure

Food Self-Sufficiency, Comparative Advantage, and Agricultural Trade: A Policy Analysis Matrix for Chinese Agriculture

We assess the comparative advantage and protection of China’s major agricultural crops using a modified Policy Analysis Matrix (PAM) and 1996 to 1998 data. We consider the following commodities: early indica rice, late indica rice, japonica rice, south wheat, north wheat, south corn, north corn, sorghum, soybean, rapeseed, cotton, tobacco, sugarcane, and a subset of fruits and vegetables. Consistent with the intuition of the simple Heckscher-Ohlin model, the results strongly suggest that China has a comparative advantage in labor-intensive crops, and a disadvantage in land-intensive crops. Specifically, land-intensive grain and oilseed crops are less socially profitable than fruits and vegetables. Within the grain sector, high quality rice and high quality north wheat have a more comparative advantage than early indica rice and south wheat, respectively. The findings suggest that China’s current grain self-sufficiency policy incurs efficiency losses. Our results shed light on likely changes in agricultural trade patterns in China, if accession to the World Trade Organization (WTO) takes place. We also stress the need for greater input productivity in grain production to improve its competitiveness if China keeps its food security policy

Urban Demand for Edible Oils and Fats in China: Evidence from Household Survey Data

Using urban household-level survey data from 1992 to 1998, we provide estimates of final demand for edible vegetable oils and animal fats in three regions of China based on an incomplete demand system. For each region, the demand for the major staple oil is price inelastic. The aggregate demand for nonstaple and condiment oils is more responsive to price changes and is elastic in some cases. All edible oils have positive income elasticity, but smaller than one. The share of animal fat in total fat and oil consumption is decreasing with rising income. Older and smaller households exhibit larger per-capita consumption of oils and fats. Exact measures of urban consumer welfare losses associated with trade restrictions on vegetable oil imports indicate that these urban consumers suffer a significant surplus loss as high as $679.19 million in 1998 U.S. dollars. J. Comp. Econ., December 2002, 30(4), pp. 732–753. Department of Economics and Center for Agricultural and Rural Development, Iowa State University, Ames, Iowa 50011-1070; and Institut National de Recherche Agronomique Paris-grignon 75231 Paris, France

Ceraclea of the People\u27s Republic of China (Trichoptera: Leptoceridae)

The species of the long-horned caddisfly genus Ceraclea for the People\u27s Republic of China are reviewed for the first time since 1975. Twenty-nine species of Ceraclea are known from China and are described or redescribed in the subgenera Ceraclea and Athripsodina, with 4 of them new to science

Setodini of the People\u27s Republic of China (Trichoptera: Leptoceridae, Leptocerinae)

The Chinese species of the long-horned caddisly tribe Setodini are reviewed, based on the recent revision by Schmid. Twenty-two species of Setodini are reported from China, including six species previously described in the paraphyletic Setodes and one in monophyletic Trichosetodes, twelve species being described as new to science in Setodes and one Trichosetodes, and two unnamed species of Setodes whose females are described

Flood Wave-Tide Wave Interaction on the James River During the Agnes Flood

During the Agnes flood hourly tidal height data were collected at seven locations along the tidal James River and currents were measured at two transects in the lower James. A comparison between actual tides and currents and the predicted tidal features as given by the tide and tidal current tables of NOAA was made. Results of this comparison show that Agnes did significantly affect water levels in the upper portion of the tidal James, especially near Richmond. However in the lower portion of the James no discernible rise was evident due to the passage of the flood crest. A small storm surge (\u3c2 \u3efeet) was noted on the day of the passage of Agnes, 21 June, throughout the tidal James. A phase shift in times of high and low water due to the interaction of the two wave systems was not observed. In the freshwater portion of the tidal James currents continually ebbed during the passage of the flood crest. In the saline portion of the system, the flood effect on the currents was limited to the surface portion of the channel.https://scholarworks.wm.edu/vimsbooks/1065/thumbnail.jp