4,108 research outputs found
Population pressure and the microeconomy of land management in hills and mountains of developing countries:
Concerns about harmful environmental impacts are frequently raised in research and policy debates about population growth in the hills and mountains of developing countries. Although establishing wildlife corridors and biosphere reserves is important for preserving selected biodiverse habitats, for the vast majority of hilly-mountainous lands, the major ecological concerns are for the sustainability of local production systems and for watershed integrity. What matters for sustained use of those lands not only is the number of producers but also what, where and how they produce. Evidence from empirical research indicates that population growth in hills and mountains can lead to land enhancement, degradation, or aspects of both. This can be explained by extending induced innovation theory to address environmental impacts of intensification. Increases in the labor-land endowment ratios of households and in local land demand and labor supply make the opportunity cost of land relative to labor increase. As a result, people use hilly-mountainous land resources more intensively for production and consumption, thus tending to deplete resources and significantly alter habitats. But, at the same time, capital- and labor-intensive methods of replenishing or improving soil productivity may become economically more attractive, production systems that enhance the land if the expected discounted returns are greater than those of systems that degrade the land. Users will choose production systems that enhance the land if the expected discounted returns are greater than those of systems that degrade the land. In addition to population change, other factorsâmarket conditions, local institutions and organizations, information and technology about resource management, and local ecological conditionsâdetermine the returns from various production systems.Environmental impact analysis., Population density.,
The pulsation spectrum of VX Hydrae
We present the results of a two-year, multisite observing campaign
investigating the high-amplitude delta Scuti star VX Hydrae during the 2006 and
2007 observing seasons. The final data set consists of nearly 8500 V-band
observations spanning HJD 2453763.6 to 2454212.7 (2006 January 28 to 2007 April
22). Separate analyses of the two individual seasons of data yield 25
confidently-detected frequencies common to both data sets, of which two are
pulsation modes, and the remaining 23 are Fourier harmonics or beat frequencies
of these two modes. The 2006 data set had five additional frequencies with
amplitudes less than 1.5 mmag, and the 2007 data had one additional frequency.
Analysis of the full 2006-2007 data set yields 22 of the 25 frequencies found
in the individual seasons of data. There are no significant peaks in the
spectrum other than these between 0 and 60 c/d. The frequencies of the two main
pulsation modes derived from the 2006 and 2007 observing seasons individually
do not differ at the level of 3-sigma, and thus we find no conclusive evidence
for period change over the span of these observations. However, the amplitude
of f(1) = 5.7898 c/d changed significantly between the two seasons, while the
amplitude of f(0) = 4.4765 c/d remained constant; amplitudes of the Fourier
harmonics and beat frequencies of f(1) also changed. Similar behavior was seen
in the 1950s, and it is clear that VX Hydrae undergoes significant amplitude
changes over time.Comment: 14 pages, 5 figures, published in Publications of the Astronomical
Society of the Pacific, v.121, p.1076 (October 2009
ECONOMIC IMPACTS OF CALIFORNIA'S GOLF COURSE FACILITIES IN 2000
People spent 7.872 billion, 1.370 billion in 2000. Direct sales of $4.251 billion directly supported 62,173 jobs, and , through indirect and induced sales impacts, an additional 37,609 jobs.Land Economics/Use,
Three-Dimensional Massive Gauge Theories
Three-dimensional Yang-Mills and gravity theories augmented by gauge-invariant mass terms are analyzed. These topologically nontrivial additions profoundly alter the particle content of the models and lead to quantization of a dimensionless mass-coupling-constant ratio. The vector field excitations become massive, with spin 1 (rather than massless with spin 0), and the mass provides an infrared cutoff. The gravitation acquires mass, mediates finite-range interactions, and has spin 2 (rather than being absent altogether); although its mass term is of third derivative order, there are no ghosts or acausalities
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