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  • 1995-1999  (2)
  • 1980-1984  (11)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Review of industrial organization 4 (1995), S. 595-607 
    ISSN: 1573-7160
    Schlagwort(e): captive breeding ; in situ conservation ; ex situ conservation ; zoos ; protected areas
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Wirtschaftswissenschaften
    Notizen: Abstract Growing deterministic and stochastic threats to many wild populations of large vertebrates have focused attention on the conservation significance of captive breeding and subsequent reintroduction. However, work on both gorillas and black rhinos questions this shift in emphasis. In these species, field-based conservation can be effective if properly supported and, although this is not cheap, per capita costs may still be considerably lower than for ex situ propagation in captivity. Here we attempt to broaden the scope of this debate by contrasting the breeding success and costs of in situ and captive programmes for a range of threatened mammals. Data are scarce, but we find that across nine large-bodied genera, in situ conservation achieves comparable rates of population growth to those seen in established captive breeding programmes. Moreover, comparing budgets of well-protected reserves with zoos' own estimates of maintenance costs and the costs of zoo adoption schemes, we find that per capita costs for effective in situ conservation are consistently lower than those of maintenance in captivity. Captive breeding may be more cost-effective for smaller-bodied taxa, and will often remain desirable for large mammals restricted to one or two vulnerable wild populations. However, our results, coupled with the fact that effective in situ conservation protects intact ecosystems rather than single species, lead us to suggest that zoos might maximize their contribution to large mammal conservation by investing where possible in well-managed field-based initiatives, rather than establishing additional ex situ breeding programmes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Publikationsdatum: 1995-08-01
    Print ISSN: 0960-3115
    Digitale ISSN: 1572-9710
    Thema: Biologie
    Publiziert von Springer
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Publikationsdatum: 1982-08-01
    Print ISSN: 0034-6748
    Digitale ISSN: 1089-7623
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Publikationsdatum: 1984-08-01
    Print ISSN: 0034-6748
    Digitale ISSN: 1089-7623
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Publikationsdatum: 2011-08-18
    Schlagwort(e): NONMETALLIC MATERIALS
    Materialart: AIAA Journal (ISSN 0001-1452); 22; 1491-149
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Publikationsdatum: 2019-06-28
    Beschreibung: The stagnation-point ablation rates of a graphite, a carbon-carbon composite, and four carbon-phenolic materials are measured in an arc-jet wind tunnel with a 50 percent hydrogen-50 percent helium mixture as the test gas. Flow environments are determined through measurements of static and impact pressures, heat-transfer rates to a calorimeter, and radiation spectra, and through numerical calculation of the flow through the wind tunnel, spectra, and heat-transfer rates. The environments so determined are: impact pressure approximately equal to 3 atm, Mach number approximately equal to 2.1, convective heat-transfer rate approximately equal to 14 kW/sq cm, and radiative heat-transfer rate approximately equal to 7 kW/sq cm in the absence of ablation. Ablation rates are determined from the measured rates of mass loss and recession of the ablation specimens. Compared with the predicted ablation rates obtained by running RASLE and CMA codes, the measured rates are higher by about 15 percent for all tested materials.
    Schlagwort(e): NONMETALLIC MATERIALS
    Materialart: AIAA PAPER 83-1561
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Publikationsdatum: 2019-06-28
    Beschreibung: The Space Shuttle Orbiter Experiments program in responsible for collecting flight data to extend the research and technology base for future aerospace vehicle design. The Infrared Imagery of Shuttle (IRIS), Catalytic Surface Effects, and Tile Gap Heating experiments sponsored by Ames Research Center are part of this program. The paper describes the software required to process the flight data which support these experiments. In addition, data analysis techniques, developed in support of the IRIS experiment, are discussed. Using the flight data base, the techniques have provided information useful in analyzing and correcting problems with the experiment, and in interpreting the IRIS image obtained during the entry of the third Shuttle mission.
    Schlagwort(e): SPACE TRANSPORTATION
    Materialart: AIAA PAPER 83-1532
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Publikationsdatum: 2019-06-28
    Beschreibung: The stagnation-point ablation rates of a graphite, a carbon-carbon composite, and four carbon-phenolic materials are measured in an arc-jet wind tunnel with a 50% hydrogen-50% helium mixture as the test gas. Flow environments are determined through measurements of static and impact pressures, heat-transfer rates to a calorimeter, and radiation spectra, and through numerical calculation of the flow through the wind tunnel, spectra, and heat-transfer rates. The environments so determined are: impact pressure approx. 3 atm, Mach number approx. 2.1, convective heat-transfer rate approx. 14 kw/sq cm, and radiative heat-transfer rate approx. 7 kw/sq cm in the absence of ablation. Ablation rates are determined from the measured rates of mass loss and recession of the ablation specimens. Compared with the predicted ablation rates obtained by running RASLE and CMA codes, the measured rates are higher by about 15% for all tested materials.
    Schlagwort(e): SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: NASA-TM-84346 , A-9286 , NAS 1.15:84346
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Publikationsdatum: 2019-06-28
    Beschreibung: This paper presents thermal protection system (TPS) requirements for a potential Titan aerocapture vehicle. Shock-layer solutions are obtained for a nominal trajectory through the current Titan model atmosphere. Fully laminar and fully turbulent solutions are presented along the blunted fore-cone in the windward symmetry plane of a bent-biconic vehicle. Using these solutions to define the aerothermodynamic environment, transient material-response solutions are obtained for a Galileo-type TPS with a carbon-phenolic ablator heat shield. Shock-layer results indicate that turbulent flow is the more realistic flow condition. They also show that the lengthy aerocapture heating pulse is dominated by convective heating. The TPS results show that the required insulation thickness is uniformly about 4 cm along the fore-cone because of the long heat-soak period. The total heat-shield thickness is 6.4 cm at the stagnation point, and 4.7 cm near the end of the fore-cone. These TPS requirements are greater than those presented in a previous Titan aerocapture study.
    Schlagwort(e): AERODYNAMICS
    Materialart: AIAA PAPER 84-1714
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Publikationsdatum: 2019-07-13
    Beschreibung: A new code for the simulation of full (forebody and base region) flowfields about bluff bodies in the hypersonic regime of severe planetary entry is described. The present 'maximally conservative, maximally differenced' formulation of the unsteady compressible Navier-Stokes equations for 2-D axisymmetric 3-D flow is contrasted for stability with previous formulations of Viviand, Kutler, et al, and Thomas and Lombard. Discrete metric relations peculiar to the axisymmetric finite volume formulation are presented along with a general discussion of their relations to and consequences of failure to close computational cells. A computational mesh of curvilinear coordinate topology singular in the flow regime is presented that permits aligned capturing of the major physical features of the complex flowfield.
    Schlagwort(e): AERODYNAMICS
    Materialart: AIAA PAPER 80-0065 , Aerospace Sciences Meeting; Jan 14, 1980 - Jan 16, 1980; Pasadena, CA
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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