This paper considers anew the simultaneity problem that arises when observations of transactions are used to study the demand behavior of pricetaking consumers. Simultaneity is shown to be a problem of censored outcomes. This fact is used to obtain a basic negative finding on identification in the absence of prior information on the structure of demand or the process of price determination. The...

The Sloping Land Conversion Program (also known as "Grain for Green" or the Upland Conversion Program) for converting cropland to forest is one of China's most ambitious environmental initiatives, and is one of the world's largest land-conservation programs with a budget of RMB 337 billion (over US$ 40 billion). Although environmental impacts have played a vital role in the general reasoning an...

Plans call for five T-phase stations to be installed as part of hydroacoustic segment of the International Monitoring System (IMS), for use in detecting nuclear explosions in the oceans. The ability to detect T-phase signals at the seismic T-phase stations relies on an understanding of the transition from ocean-borne acoustic energy to seismic energy. Observations of the seismic T-phase indicat...

Sandy soils are prone to nutrient losses, and consequently do not have as much agricultural productivity other soils. In this study, coal fly ash (CFA) anionic polyacrylamide (PAM) granules were used a sandy soil amendment. The two additives incorporated the layer (depth of 0.2 m, slope gradient 10°) at three CFA dosages PAM dosages. Urea was applied uniformly onto low-nitrogen (N) surface prio...

For over 16 years, the Precipitation Radar of the Tropical Rainfall Measuring Mission (TRMM) satellite detected the three-dimensional structure of significantly precipitating clouds in the tropics and subtropics. This paper reviews and synthesizes studies using the TRMM radar data to present a global picture of the variation of convection throughout low latitudes. The multiyear data set shows c...

TruSurf is a new system for building solid objects from layers with sloping surfaces that closely match the designed surface shape. The advantages of using sloping surfaces over stepped edges are improved surface finish, and decreased build time through the use of thicker layers. TruSurf uses B-spline surfaces to describe the part, and calculate the sloped path of the layer cutting medium. The ...

Cropland abandonment has emerged as a prevalent phenomenon in the mountainous areas of China. While there is a general understanding that this new trend is driven by the rising opportunity cost of rural labor, rigorous theoretical and empirical analyses are largely absent. This paper first develops a theoretical model to investigate household decisions on farming scale when off-farm labor marke...

Soil water availability is most essential in the Sahelian agriculture but is hampered by several factors. Surface crusts or crust-like surfaces, which are characteristic of most Sahelian soils, have been shown to decrease water in®ltrability and increase runoff. Their type and structure are in ̄uenced by soil texture, vegetation cover, erosion and deposition effects of wind and water. A soil and...

The Three Gorges Reservoir Area is one of the most severe soil erosion in China. Serious erosion has degraded the soil productivity, deteriorated the ecological environment, and influenced the service life of Three Gorges Reservoir. The natural and social-economic factors which influence the soil erosion in Three Gorges Reservoir Area include topography, geological situation, vegetation, rainfa...