2,051 research outputs found

    The World's Conservation Strategy

    Get PDF
    Rational use and conservation of living resources must be the active concern of all of us, rich and poor alike, if the world is to continue to develop in any reasonable degree of harmony with Nature. Accordingly it is necessary to recognize that industrial—and even some degree of demographic—development is not necessarily incompatible with environmental protection, and indeed that, in the world to come, conservation and development will have to be widely interlinked. Cognizant of this and of the fundamental need to protect and perpetuate living, renewable resources in the face of ever-mounting and demanding human populations, and stressing the imperative of preserving a holistic approach to these problems of Man's and Nature's ‘only one Earth', IUCN, with the support of UNEP and WWF, and the endorsement of some other bodies, launched, early in 1980, after several laborious redraftings, a ‘World Conservation Strategy', in the manner described in the last part of this paper. It sets a policy for all to follow, taking mankind well away from the merely reactionist basis of conservatio

    Translating Environmental Science into Policy and Action

    Get PDF
    Background/Question/Methods: Many ecologists are skilled at identifying environmental problems and defining solutions, but not at achieving concrete action to implement those insights. The question, then, is how to help ecologists translate environmental science into policy and action. Most ecologists' education and training do not prepare them to be effective in the policy arena, much less in ways to achieve action. Ecologists find disincentives in the form of the academic attitude that somehow the application of science is inferior to so-called "pure science." This ivory tower holdover has been largely discredited in the context of environmental issues, and the discipline of conservation biology exists explicitly to foster applications of science, but the attitude remains a potent obstacle, especially for younger ecologists seeking academic acceptance and tenure. Even when ecologists ignore or overcome this obstacle there are few resources available to provide guidance for achieving action. For example, most textbooks that describe the policy process present an academic picture that bears little relationship to the messy real world process. One approach to providing such guidance has been developed in the Department of Environmental Science and Policy at George Mason University, Fairfax, Virginia. This is a course developed specifically to identify and analyze the basic principles, skills and strategies involved in turning scientific knowledge and information, and the policies derived from them, into action. The course uses a series of actual case histories drawn from experience with local and national U.S. and foreign governments, UN organizations, NGOs and other relevant situations. The approach is to give a case hissory, analyze it and derive from it the principles, strategies and skills that work. The professor describes the setting, background, objective, procedure followed and the result. This is followed by class discussion to analyze the case and identify what lessons can be learned and what specific principles, skills and strategies were responsible for or contributed to the results.

Results/Conclusions: While there are some basic principles that hold true in many situations, no single formula for achieving action can be applied in every case. Each situation is somewhat different and to succeed one has to be able to select from an array of principles and skills to fit them to the special needs. This course is a proven way to provide students with a "tool kit" of principles, skills and strategies to guide them effectively to translate environmental science into policy and action

    IUCN in Retrospect and Prospect

    Get PDF
    IUCN is a unique, international but independent, organization which promotes and carries on scientifically-based action for conservation throughout the world. Founded originally for the ‘Protection of Nature', it has evolved greatly in the intervening nearly 35 years in response to current needs, and now occupies a very prominent position in the environmental/conservational movement to withstand ever-increasing human population-pressures through rational use of resources and seeking to assure that development is environmentally soun

    Large-scale distributions of tropospheric nitric, formic, and acetic acids over the western Pacific basin during wintertime

    Get PDF
    We report here measurements of the acidic gases nitric (HNO3), formic (HCOOH), and acetic (CH3COOH) over the western Pacific basin during the February-March 1994 Pacific Exploratory Mission-West (PEM-West B). These data were obtained aboard the NASA DC-8 research aircraft as it flew missions in the altitude range of 0.3–12.5 km over equatorial regions near Guam and then further westward encompassing the entire Pacific Rim arc. Aged marine air over the equatorial Pacific generally exhibited mixing ratios of acidic gases \u3c100 parts per trillion by volume (pptv). Near the Asian continent, discrete plumes encountered below 6 km altitude contained up to 8 parts per billion by volume (ppbv) HNO3 and 10 ppbv HCOOH and CH3COOH. Overall there was a general correlation between mixing ratios of acidic gases with those of CO, C2H2, and C2Cl4, indicative of emissions from combustion and industrial sources. The latitudinal distributions of HNO3 and CO showed that the largest mixing ratios were centered around 15°N, while HCOOH, CH3COOH, and C2Cl4 peaked at 25°N. The mixing ratios of HCOOH and CH3COOH were highly correlated (r2 = 0.87) below 6 km altitude, with a slope (0.89) characteristic of the nongrowing season at midlatitudes in the northern hemisphere. Above 6 km altitude, HCOOH and CH3COOH were marginally correlated (r2 = 0.50), and plumes well defined by CO, C2H2, and C2Cl4 were depleted in acidic gases, most likely due to scavenging during vertical transport of air masses through convective cloud systems over the Asian continent. In stratospheric air masses, HNO3 mixing ratios were several parts per billion by volume (ppbv), yielding relationships with O3 and N2O consistent with those previously reported for NOy

    Nature And Human Nature

    Get PDF

    Jamming coverage in competitive random sequential adsorption of binary mixture

    Full text link
    We propose a generalized car parking problem where cars of two different sizes are sequentially parked on a line with a given probability qq. The free parameter qq interpolates between the classical car parking problem of only one car size and the competitive random sequential adsorption (CRSA) of a binary mixture. We give an exact solution to the CRSA rate equations and find that the final coverage, the jamming limit, of the line is always larger for a binary mixture than for the uni-sized case. The analytical results are in good agreement with our direct numerical simulations of the problem.Comment: 4 pages 2-column RevTeX, Four figures, (there was an error in the previous version. We replaced it (including figures) with corrected and improved version that lead to new results and conclusions

    Test Characteristics of Urinary Lipoarabinomannan and Predictors of Mortality among Hospitalized HIV-Infected Tuberculosis Suspects in Tanzania.

    Get PDF
    Tuberculosis is the most common cause of death among patients with HIV infection living in tuberculosis endemic countries, but many cases are not diagnosed pre-mortem. We assessed the test characteristics of urinary lipoarabinomannan (LAM) and predictors of mortality among HIV-associated tuberculosis suspects in Tanzania. We prospectively enrolled hospitalized HIV-infected patients in Dar es Salaam, with ≥2 weeks of cough or fever, or weight loss. Subjects gave 2 mLs of urine to test for LAM using a commercially available ELISA, ≥2 sputum specimens for concentrated AFB smear and solid media culture, and 40 mLs of blood for culture. Among 212 evaluable subjects, 143 (68%) were female; mean age was 36 years; and the median CD4 count 86 cells/mm(3). 69 subjects (33%) had culture confirmation of tuberculosis and 65 (31%) were LAM positive. For 69 cases of sputum or blood culture-confirmed tuberculosis, LAM sensitivity was 65% and specificity 86% compared to 36% and 98% for sputum smear. LAM test characteristics were not different in patients with bacteremia but showed higher sensitivity and lower specificity with decreasing CD4 cell count. Two month mortality was 64 (53%) of 121 with outcomes available. In multivariate analysis there was significant association of mortality with absence of anti-retroviral therapy (p = 0.004) and a trend toward association with a positive urine LAM (p = 0.16). Among culture-negative patients mortality was 9 (75%) of 12 in LAM positive patients and 27 (38%) of 71 in LAM negative patients (p = 0.02). Urine LAM is more sensitive than sputum smear and has utility for the rapid diagnosis of culture-confirmed tuberculosis in this high-risk population. Mortality data raise the possibility that urine LAM may also be a marker for culture-negative tuberculosis

    Model of correlated sequential adsorption of colloidal particles

    Get PDF
    We present results of a new model of sequential adsorption in which the adsorbing particles are correlated with the particles attached to the substrate. The strength of the correlations is measured by a tunable parameter σ\sigma. The model interpolates between free ballistic adsorption in the limit σ→∞\sigma\to\infty and a strongly correlated phase, appearing for σ→0\sigma\to0 and characterized by the emergence of highly ordered structures. The phenomenon is manifested through the analysis of several magnitudes, as the jamming limit and the particle-particle correlation function. The effect of correlations in one dimension manifests in the increased tendency to particle chaining in the substrate. In two dimensions the correlations induce a percolation transition, in which a spanning cluster of connected particles appears at a certain critical value σc\sigma_c. Our study could be applicable to more general situations in which the coupling between correlations and disorder is relevant, as for example, in the presence of strong interparticle interactions.Comment: 6 pages, 8 EPS figures. Phys. Rev. E (in press

    On the stability of very massive primordial stars

    Full text link
    The stability of metal-free very massive stars (ZZ = 0; M = 120 - 500 \msol) is analyzed and compared with metal-enriched stars. Such zero-metal stars are unstable to nuclear-powered radial pulsations on the main sequence, but the growth time scale for these instabilities is much longer than for their metal-rich counterparts. Since they stabilize quickly after evolving off the ZAMS, the pulsation may not have sufficient time to drive appreciable mass loss in Z = 0 stars. For reasonable assumptions regarding the efficiency of converting pulsational energy into mass loss, we find that, even for the larger masses considered, the star may die without losing a large fraction of its mass. We find a transition between the ϵ\epsilon- and κ\kappa-mechanisms for pulsational instability at Z\sim 2\E{-4} - 2\E{-3}. For the most metal-rich stars, the κ\kappa-mechanism yields much shorter ee-folding times, indicating the presence of a strong instability. We thus stress the fundamental difference of the stability and late stages of evolution between very massive stars born in the early universe and those that might be born today.Comment: 7 pages, 5 figures. Minor changes, more results given in Table 1, accepted for publication in Ap
    • …
    corecore