After 50 years of steady increase, per capita visits to U.S. National Parks have declined since 1987. To evaluate whether we are seeing a fundamental shift away from people's interest in nature, we tested for similar longitudinal declines in 16 time series representing four classes of nature participation variables: (i) visitation to various types of public lands in the U.S. and National Parks in Japan and Spain, (ii) number of various types of U.S. game licenses issued, (iii) indicators of time spent camping, and (iv) indicators of time spent backpacking or hiking. The four variables with the greatest per capita participation were visits to Japanese National Parks, U.S. State Parks, U.S. National Parks, and U.S. National Forests, with an average individual participating 0.74-2.75 times per year. All four time series are in downtrends, with linear regressions showing ongoing losses of -1.0% to -3.1% per year. The longest and most complete time series tested suggest that typical declines in per capita nature recreation began between 1981 and 1991, are proceeding at rates of -1.0% to -1.3% per year, and total to date -18% to -25%. Spearman correlation analyses were performed on untransformed time series and on transformed percentage year-to-year changes. Results showed very highly significant correlations between many of the highest per capita participation variables in both untransformed and in difference models, further corroborating the general downtrend in nature recreation. In conclusion, all major lines of evidence point to an ongoing and fundamental shift away from nature-based recreation.
We calculate the neutron-Calcium-60 S-wave scattering phase shifts using
State of the art coupled-cluster theory combined with modern ab initio
Interactions derived from chiral effective theory. Effects of three-nucleon
Forces are included schematically as density dependent nucleon-nucleon
We describe a simple limit that emerges when interference is
Common, in which the fitness effects of individual mutations play a relatively
Minor role. Instead, molecular evolution is determined by the variance in
Fitness within the population, defined over an effectively asexual segment of
Photons entangled in angular momentum and radial modes. We unambiguously verify
That these photons are highly entangled in most 2x2-dimensional subspaces of a
34.500-dimensional Hilbert space, which suggests the generation of genuine high
Dimensional entanglement. We develop a source-ind...
Pubget Updates sends you emails when Pubget finds new papers that match your search. Use Pubget Updates to get the latest articles for your specialty, written by a colleague, or published by your favorite journals.