18,624 research outputs found
Defining, Valuing, and Providing Ecosystem Goods and Services
Ecosystem services are the specific results of ecosystem processes that either directly sustain or enhance human life (as does natural protection from the sun's harmful ultraviolet rays) or maintain the quality of ecosystem goods (as water purification maintains the quality of streamflow). "Ecosystem service" has come to represent several related topics ranging from the measurement to the marketing of ecosystem service flows. In this article we examine several of these topics by first clarifying the meaning of "ecosystem service" and then (1) placing ecosystem goods and services within an economic framework, emphasizing the role and limitations of substitutes; (2) summarizing the methods for valuation of ecosystem goods and services; and (3) reviewing the various approaches for their provision and financing.Many ecosystem services and some ecosystem goods are received without monetary payment. The "marketing" of ecosystem goods and services is basically an effort to turn such recipients - those who benefit without ownership- into buyers, thereby providing market signals that serve to help protect valuable goods and services. We review various formal arrangements for making this happen
Prominence and flare fine structure from cross-field thermal conduction
Thermal conduction across a magnetic field is strongly suppressed compared
with conduction along the field. However, if a flare is heated by a highly
filamented beam directed along the field, then the array of heated cells in a
cross-section of the flare will result in both small spatial scales (with
consequently large temperature gradients) and a large surface area for the
heated volume, providing a geometrical enhancement of the total cross-field
energy flux. To investigate the importance of this filamentary geometry, we
present a simple model of a single heated filament surrounded by an optically
thin radiating shell, obtain an analytical expression for the stable
equilibrium temperature profile within the shell, and use this to impose limits
on the size of filament for which this model is appropriate.
We find that this mechanism by itself is capable of transporting a power of
the same order as a large flare, with a moderate range of filament sizes. The
length scales are substantially smaller than can be resolved at present,
although they should be regarded as underestimates.Comment: 7 pages, LaTeX, 4 figures. Source, figures and PS at
http://www.astro.gla.ac.uk/preprints/95-05.html . To appear in A&
Testing the General Validity of the Heckscher-Ohlin Theorem: The Natural Experiment of Japan
We exploit Japan's 19th century opening up to trade to test a general formulation of the Heckscher-Ohlin theorem. This formulation is based on Ohlin's measure of factor scarcity where autarky factor prices impose a refutable prediction on the economy's factor content of trade. Our test combines factor price data in Japan's autarky period with commodity trade data and a technology matrix in Japan's early free trade period. Our technology matrix is derived from a major Japanese survey of agricultural techniques during the early Meiji period, accounts by European visitors and numerous studies by Japanese and western scholars that draw on village records, business accounts and other historical sources. Evaluating Japan's factor content of trade during 1868-1875 at the corresponding autarky factor prices, we fail to reject the Heckscher-Ohlin prediction in each sample year.
Testing the general validity of the Heckscher-Ohlin Theorem: the natural experiment of Japan
We exploit Japan's 19th century opening up to trade to test a general formulation of the Heckscher-Ohlin theorem. This formulation is based on Ohlin's measure of factor scarcity where autarky factor prices impose a refutable prediction on the economy's factor content of trade. Our test combines factor price data in Japan's autarky period with commodity trade data and a technology matrix in Japan's early free trade period. Our technology matrix is derived from a major Japanese survey of agricultural techniques during the early Meiji period, accounts by European visitors and numerous studies by Japanese and western scholars that draw on village records, business accounts and other historical sources. Evaluating Japan's factor content of trade during 1868-1875 at the corresponding autarky factor prices, we fail to reject the Heckscher-Ohlin prediction in each sample year.
Testing the General Validity of the Heckscher-Ohlin Theorem: The Natural Experiment of Japan
We exploit Japan’s 19th century move from autarky to free trade to provide the first test of the general validity of the price formulation of the Heckscher-Ohlin theorem. In this formulation a country’s autarky factor price vector imposes a single refutable prediction on the economy’s factor content of trade. Our test combines factor price data from Japan’s late autarky period with Japan’s factor content of trade calculated with the technologies of the country of origin of traded goods. The direct and indirect input requirements are constructed from many historical sources, including a major Japanese survey of agricultural techniques and a rich set of 19th century comparative cost studies. Evaluating Japan’s factor content of trade during 1865-1876 at autarky factor prices, we fail to reject the Heckscher-Ohlin hypothesis in each sample year.testing the price version of Heckscher-Ohlin, the natural experiment of Japan
The size and shape of the oblong dwarf planet Haumea
We use thermal radiometry and visible photometry to constrain the size,
shape, and albedo of the large Kuiper belt object Haumea. The correlation
between the visible and thermal photometry demonstrates that Haumea's high
amplitude and quickly varying optical light curve is indeed due to Haumea's
extreme shape, rather than large scale albedo variations. However, the
well-sampled high precision visible data we present does require longitudinal
surface heterogeneity to account for the shape of lightcurve. The thermal
emission from Haumea is consistent with the expected Jacobi ellipsoid shape of
a rapidly rotating body in hydrostatic equilibrium. The best Jacobi ellipsoid
fit to the visible photometry implies a triaxial ellipsoid with axes of length
1920 x 1540 x 990 km and density 2.6 g cm^-3$, as found by Lellouch et
al(2010). While the thermal and visible data cannot uniquely constrain the full
non-spherical shape of Haumea, the match between the predicted and measured
thermal flux for a dense Jacobi ellipsoid suggests that Haumea is indeed one of
the densest objects in the Kuiper belt.Comment: 21 pages, 2 figures, 2 tables -- Accepted for publication in Earth,
Moon and Planet
A process-oriented language for describing aspects of reading comprehension
Includes bibliographical references (p. 36-38)The research described herein was supported in part by the National Institute of Education under Contract No. MS-NIE-C-400-76-011
Site Selection for Air Pollution Monitoring in the Vicinity of Point Sources
Ever since air pollution became a national concern in the 1950\u27s, more and more emphasis has been placed on collection of representative air samples for many purposed, to include (1) evaluation of the degree to which national ambient air quality standards are being met and (2) to monitor maximum emission levels from point sources. Until recently efforts were directed toward qualitative methods of siting monitors for representative sampling. Since the dispersion of effluents is most complex, the quality of the data collected on the basis of judgment and, more or less, incremental siting about the source, has become suspect. Furthermore, with the increasing demands for monitoring due to international growth in network monitoring systems, amendments to the Clean Air Act and the legislation on the Prevention of Significant Deteoriation of Air Quality, it is not cost-effective to encircle point sources with large numbers of equally spaced monitors. This paper discussed the history of air pollution concerns that have resulted in the need for monitoring; the development of siting techniques through largely qualitative measures; and finally, summarizes three quantitative methodologies for monitoring point sources. Emphasis is placed on the methodology developed by Noll, et al., (1977), based on the author\u27s belief that this methodology represents the state of the art
TRICHOTOMOUS CHOICE: A POSSIBLE SOLUTION TO DUAL RESPONSE OBJECTIVES IN DICHOTOMOUS CHOICE CONTINGENT VALUATION QUESTIONS
We investigate the possibility that some respondents to a dichotomous choice question vote YES, even though they would not pay the posted dollar amount in order to register support for the project or policy. A trichotomous choice question format is proposed to determine if allowing respondents the opportunity to vote in favor of a project at an amount less than their bid affects estimated willingness to pay. Using univariate and multivariate tests, we find the trichotomous choice question format reduces the number of YES responses and produces a statistically significant decrease in willingness to pay for an open-space program.Research Methods/ Statistical Methods,
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