3,742 research outputs found

    Justice and the Convention on Biological Diversity

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    Benefit sharing as envisaged by the 1992 Convention on Biological Diversity (CBD) is a relatively new idea in international law. Within the context of non-human biological resources, it aims to guarantee the conservation of biodiversity and its sustainable use by ensuring that its custodians are adequately rewarded for its preservation. Prior to the adoption of the CBD, access to biological resources was frequently regarded as a free-for-all. Bioprospectors were able to take resources out of their natural habitat and develop commercial products without sharing benefits with states or local communities. This paper asks how CBD-style benefit-sharing fits into debates of justice. It is argued that the CBD is an example of a set of social rules designed to increase social utility. It is also argued that a common heritage of humankind principle with inbuilt benefit-sharing mechanisms would be preferable to assigning bureaucratic property rights to non-human biological resources. However, as long as the international economic order is characterized by serious distributive injustices, as reflected in the enormous poverty-related death toll in developing countries, any morally acceptable means toward redressing the balance in favor of the disadvantaged has to be welcomed. By legislating for a system of justice-in-exchange covering nonhuman biological resources in preference to a free-for-all situation, the CBD provides a small step forward in redressing the distributive justice balance. It therefore presents just legislation sensitive to the international relations context in the 21st century

    Computational models of cognition

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    Existing connectionist computational models of neural networks idealise the biological process in the neuron to a discrete summation, and fail to provide an efficient substrate for computation involving the spectral data that is the input to the biological perceptual process. This work presents a computational model of neural function that introduces a continuous analogue process and explores the computational uses of sub-threshold oscillations of the membrane potential. The goal of tins work is to present an in itial examination of the advantages to the practitioner that are afforded by a new computational model of the neuron that includes sub-threshold oscillations as a component on an equal footing with axonal impulses themselves. The relevant. evidence that these effects are important in a biological neural network is presented. The new resonate-and-fire model is presented and mathematically defined, and shown to be a superset of the ubiquitous integrate-and-fire model. The behaviour patterns of the model are explored initially in single neurons and then networks are examined and shown to be capable of exhibiting useful excitation patterns such as tonic oscillation, selective innervation and resonance. An unsupervised learning algorithm is defined and shown to generate networks that naturally organise to perform Fourier-style transforms central to spectral manipulations. Finally, the model is examined with respect to the current theories of computational neuroscience and cognitive science, and its p otential uses in these domains described

    Dynamical effects of multiple impacts: Large impacts on a Mars-like planet

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    The earliest stage of the evolution of a fully assembled planet is profoundly affected by a number of basin-forming impacts large enough to change the dynamics of its deeper interior. These impacts are in some cases quite closely spaced and follow one another in short time intervals, so that their effects interact and result in behavior that may differ from a simple sum of the effects of two individual and isolated impacts. We use two-dimensional models of mantle convection in a Mars-like planet and a simple parameterized representation of the principal effects of impacts to study some of the dynamical effects and interactions of multiple large impacts. In models of only two impacts, we confirm that the dynamical effects of the impacts reinforce each other the closer they are in space and time but that the effects do not always correspond to straightforward superpositions of those of single, isolated impacts. In models with multiple (4-8) impacts with variable sizes, distances, and frequencies, the global response of the mantle is as variable as the impact sequences in the short term, but in the long term the different evolutionary paths converge for several indicator variables such as the mean flow velocity, temperature, or heat flow. Nonetheless, beyond a certain impact frequency and energy, lithospheric instabilities triggered by large impacts occur on a global scale, reinvigorate mantle dynamics for long time spans, and entail a late stage of melt production in addition to the initial melting stage that is not observed in one- or two-impact models. After one or several very large impacts, some lithospheric material may founder and sink to the core-mantle boundary, and if enough of it accumulates there, it enhances the heat flux out of the core for several hundred millions of years, with possible effects on dynamo activity.Comment: 24 pages, 10 figure

    "Isocrater" impacts: Conditions and mantle dynamical responses for different impactor types

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    Impactors of different types and sizes can produce a final crater of the same diameter on a planet under certain conditions. We derive the condition for such "isocrater impacts" from scaling laws, as well as relations that describe how the different impactors affect the interior of the target planet; these relations are also valid for impacts that are too small to affect the mantle. The analysis reveals that in a given isocrater impact, asteroidal impactors produce anomalies in the interior of smaller spatial extent than cometary or similar impactors. The differences in the interior could be useful for characterizing the projectile that formed a given crater on the basis of geophysical observations and potentially offer a possibility to help constrain the demographics of the ancient impactor population. A series of numerical models of basin-forming impacts on Mercury, Venus, the Moon, and Mars illustrates the dynamical effects of the different impactor types on different planets. It shows that the signature of large impacts may be preserved to the present in Mars, the Moon, and Mercury, where convection is less vigorous and much of the anomaly merges with the growing lid. On the other hand, their signature will long have been destroyed in Venus, whose vigorous convection and recurring lithospheric instabilities obliterate larger coherent anomalies.Comment: 32 pages, 12 figure

    A topological solution to object segmentation and tracking

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    The world is composed of objects, the ground, and the sky. Visual perception of objects requires solving two fundamental challenges: segmenting visual input into discrete units, and tracking identities of these units despite appearance changes due to object deformation, changing perspective, and dynamic occlusion. Current computer vision approaches to segmentation and tracking that approach human performance all require learning, raising the question: can objects be segmented and tracked without learning? Here, we show that the mathematical structure of light rays reflected from environment surfaces yields a natural representation of persistent surfaces, and this surface representation provides a solution to both the segmentation and tracking problems. We describe how to generate this surface representation from continuous visual input, and demonstrate that our approach can segment and invariantly track objects in cluttered synthetic video despite severe appearance changes, without requiring learning.Comment: 21 pages, 6 main figures, 3 supplemental figures, and supplementary material containing mathematical proof

    Toward the morphometric calibration of the environmental biorecorder Arctica islandica

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    Owing to its extremely long life span and occurrence in the entire North Atlantic, the Arctic boreal Arctica islandica has become of particular significance for monitoring the environment, because information on past environmental conditions is archived in morphological and biogeochemical properties of the calcareous shell. To evaluate whether such properties are comparable between different localities, shell and soft body morphometry of six A. islandica populations, Norwegian Coast, Kattegat, Kiel Bay (Baltic), White Sea, German Bight (North Sea), and off NE Iceland, were compared. Discriminant analysis indicated distinct differences between populations, albeit not related to geographical distance, but more likely to local hydrography, bottom morphology, and food regime

    The redundant target paradigm and its use as a blindsight-test : A meta-analytic study

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    Acknowledgements We would like to thank Malte Kühn for his invaluable help in conducting and rating the systematic literature research. Funding This research was supported by a grant from the German Research Foundation (Deutsche Forschungsgemeinschaft: DFG-SCHE 735/3-2).Peer reviewedPostprin

    Advanced Refrigerator/Freezer Technology Development. Technology Assessment

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    The NASA Lewis Research Center, through contract with Oceaneering Space Systems, is engaged in a project to develop advanced refrigerator/freezer (R/F) technologies for future Life and Biomedical Sciences space flight missions. The first phase of this project, a technology assessment, has been completed to identify the advanced R/F technologies needed and best suited to meet the requirements for the five R/F classifications specified by Life and Biomedical Science researchers. Additional objectives of the technology assessment were to rank those technologies based on benefit and risk, and to recommend technology development activities that can be accomplished within this project. This report presents the basis, the methodology, and results of the R/F technology assessment, along with technology development recommendations
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