32,149 research outputs found
Comparative Advantage in Tourism - A Supply-Side Analysis of Tourism Flows
The purpose of the paper is to relate the tourism demand model with the traditional theories that explain international trade flows. In the existing tourism literature, tourism flows and tourism demand forecasts are typically explained by the demand-side variables. But in the traditional trade theories, international trade flows are explained from the supply-side variables, i.e. the comparative advantage of the exporting countries. A model is proposed in the paper, trying to explain in a modern and global economy, the factors that from a supply-side perspective can decide the comparative advantage of countries in a certain type of service activity. The preliminary results render a strong support for the relevance of certain supply-side factors in explaining international tourism flows such as both natural endowments and created assets associated with foreign investments, hotel capacity and level of development.
Simulating Root Density Dynamics and Nitrogen Uptake -Field Trials and Root Model Approach in Denmark
Plant soil and atmosphere models are commonly used to predict crop yield and associated environmental consequences. Such models often include complex modelling of water movement, soil organic matter turnover and above ground plant growth. However, the root modelling in these models is often very simple, partly due to a limited access to experimental data. Here we propose a root model developed to describe root growth, root density and nitrogen uptake. The model focuses on annual crops, and attempts to model root growth of different crop species and row crops and its significance for nitrogen uptake from different parts of the soil volume
Simulating Root Density Dynamics and Nitrogen Uptake â Can a Simple Approach be Sufficient?
The modeling of root growth in many plantâsoil models is simple and with few possibilities to adapt simulated root proliferation and depth distribution to that actually found with different crop species. Here we propose a root model, developed to describe root growth, root density and nitrogen uptake. The model focuses on annual crops, and attempts to model root growth of different crop species and row crops and its significance for nitrogen uptake from different parts of the soil volume
An Evaluation of Tennessee Soybean Growersâ Views on a New Generation Cooperative to Produce Biodiesel
Substituting petroleum diesel with biodiesel could decrease air emissions, reduce reliance on foreign oil, and help expand markets for U.S. farmers. Soybean producers can potentially capture this value-added by forward integrating the processing of soybeans into biodiesel via a New Generation Cooperative (NGC). Using probit analysis, this study examines factors influencing soybean producersâ willingness to participate in an NGC to produce biodiesel. Tobit analysis is used to examine the factors influencing the number of shares the soybean producer would be willing to purchase. Survey results indicate that over 70% of the soybean producers in the study group are interested in investing in an NGC to produce biodiesel. Among those producers willing to participate, the average number of shares they would purchase was just under 3,460.biodiesel, New Generation Cooperative, probit analysis, soybean producers, tobit analysis, Marketing, Research Methods/ Statistical Methods,
Topological Photonic Phase in Chiral Hyperbolic Metamaterials
Recently the possibility of achieving one-way backscatter immune
transportation of light by mimicking the topological order present within
certain solid state systems, such as topological insulators, has received much
attention. Thus far however, demonstrations of non-trivial topology in
photonics have relied on photonic crystals with precisely engineered lattice
structures, periodic on the scale of the operational wavelength and composed of
finely tuned, complex materials. Here we propose a novel effective medium
approach towards achieving topologically protected photonic surface states
robust against disorder on all length scales and for a wide range of material
parameters. Remarkably, the non-trivial topology of our metamaterial design
results from the Berry curvature arising from the transversality of
electromagnetic waves in a homogeneous medium. Our investigation therefore acts
to bridge the gap between the advancing field of topological band theory and
classical optical phenomena such as the Spin Hall effect of light. The
effective medium route to topological phases will pave the way for highly
compact one-way transportation of electromagnetic waves in integrated photonic
circuits.Comment: 11 pages, 3 figures. To appear in PR
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