44,444 research outputs found
Beyond Organic: An Overview of Biodynamic Agriculture with Case Examples
A great deal of research has been done regarding economic and consumer aspects of organic agriculture. A different form of agriculture, called biodynamic agriculture, is emerging, with acreage located across the globe. Like organic agriculture, biodynamic agriculture has a certification process, but it has not received as much research attention from agricultural economists. This paper provides basic background information about biodynamic agriculture. In particular, it gives a count of certified biodynamic farms, by state, in the U.S., and it gives the most common products produced by those farms. Wine grapes are by far the most common biodynamic agricultural product. It also includes three case examples of firms employing this production system and business strategy. The diverse case examples were developed through telephone interviews with certified biodynamic agricultural producers. It is predicted that despite its growth, biodynamic agriculture will become neither a fad nor a trend. Rather, it will remain a background influence on organic and conventional agriculture.Research and Development/Tech Change/Emerging Technologies,
The Economic Reunification of Korea: A Dynamic General Equilibrium Model
This paper constructs a dynamic specific factors model to examine the impact of the economic reunification of North and South Korea. The model is a compromise between the highly stylized neoclassical models of trade found in the theoretical trade literature, and the highly aggregated models used in dynamic macroeconomics. We find that the policies with the biggest effects on aggregate output are changes in government tax and spending rates, particularly spending on infrastructure. In contrast, we find that both skilled and unskilled wages are much more responsive to the particulars of trade policy, particularly openness to intra-Korea trade and intra-Korea labor mobility. The location of production in a fully integrated Korean economy is determined by the location of infrastructure.factor mobility; dynamic general equilibrium; specific-factors; Korea
Impacts of farming practice within organic farming systems on below-ground ecology and ecosystem function
Maintaining ecosystem function is a key issue for sustainable farming systems which contribute broadly to global ecosystem health. A focus simply on the diversity of belowground organisms is not sufficient and there is a need to consider the contribution of below-ground biological processes to the maintenance and enhancement of soil function and ecosystem services. A critical literature review on the impacts of land management practices on below-ground ecology and function shows that farm management practices can have a major impact. A particular challenge for organic farming systems is to explore to what extent reduced tillage can be adopted to the benefit of below-ground ecology without critically upsetting the whole farm management balance
Ferromagnetic material in the eastern red-spotted newt notophthalmus viridescens
Behavioral results obtained from the eastern red-spotted newt (Notophthalmus viridescens) led to the suggestion of a hybrid homing system involving inputs from both a light-dependent and a non-light-dependent mechanism. To evaluate the possible role of a receptor based on biogenic magnetite in this animal, we performed magnetometry experiments on a set of newts previously used in behavioral assays. The natural remanent magnetization (NRM) carried by these newts was strong enough to be measured easily using a direct-current-biased superconducting quantum interference device functioning as a moment magnetometer. Isothermal remanent magnetizations were two orders of magnitude higher than the NRM, suggesting that ferromagnetic material consistent with magnetite is present in the body of the newt. The NRM has no preferential orientation among the animals when analyzed relative to their body axis, and the demagnetization data show that, overall, the magnetic material grains are not aligned parallel to each other within each newt. Although the precise localization of the particles was not possible, the data indicate that magnetite is not clustered in a limited area. A quantity of single-domain magnetic material is present which would be adequate for use in either a magnetic intensity or direction receptor. Our data, when combined with the functional properties of homing, suggest a link between this behavioral response and the presence of ferromagnetic material, raising the possibility that magnetite is involved at least in the map component of homing of the eastern red-spotted newt
Effects of spaceflight on the proliferation of jejunal mucosal cells
The purpose of this project was to test the hypothesis that the generalized, whole body decrease in synthetic activity due to microgravity conditions encountered during spaceflight would be demonstrable in cells and tissues characterized by a rapid rate of turnover. Jejunal mucosal cells were chosen as a model since these cells are among the most rapidly proliferating in the body. Accordingly, the percentage of mitotic cells present in the crypts of Lieberkuhn in each of 5 rats flown on the COSMOS 2044 mission were compared to the percentage of mitotic cells present in the crypts in rats included in each of 3 ground control groups (i.e., vivarium, synchronous and caudal-elevated). No significant difference (p greater than .05) was detected in mitotic indices between the flight and vivarium group. Although the ability of jejunal mucosal cells to divide by mitosis was not impaired in flight group, there was, however, a reduction in the length of villi and depth of crypts. The concommitant reduction in villus length and crypth depth in the flight group probably reflects changes in connective tissue components within the core of villi
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