19 research outputs found

    Multiple Scenario Generation of Subsurface Models:Consistent Integration of Information from Geophysical and Geological Data throuh Combination of Probabilistic Inverse Problem Theory and Geostatistics

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    Neutrinos with energies above 1017 eV are detectable with the Surface Detector Array of the Pierre Auger Observatory. The identification is efficiently performed for neutrinos of all flavors interacting in the atmosphere at large zenith angles, as well as for Earth-skimming \u3c4 neutrinos with nearly tangential trajectories relative to the Earth. No neutrino candidates were found in 3c 14.7 years of data taken up to 31 August 2018. This leads to restrictive upper bounds on their flux. The 90% C.L. single-flavor limit to the diffuse flux of ultra-high-energy neutrinos with an E\u3bd-2 spectrum in the energy range 1.0 7 1017 eV -2.5 7 1019 eV is E2 dN\u3bd/dE\u3bd < 4.4 7 10-9 GeV cm-2 s-1 sr-1, placing strong constraints on several models of neutrino production at EeV energies and on the properties of the sources of ultra-high-energy cosmic rays

    Developing multiscale and integrative nature–people scenarios using the Nature Futures Framework

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    Scientists have repeatedly argued that transformative, multiscale global scenarios are needed as tools in the quest to halt the decline of biodiversity and achieve sustainability goals.As a first step towards achieving this, the researchers who participated in the scenarios and models expert group of the Intergovernmental Science‐Policy Platform on Biodiversity and Ecosystem Services (IPBES) entered into an iterative, participatory process that led to the development of the Nature Futures Framework (NFF).The NFF is a heuristic tool that captures diverse, positive relationships of humans with nature in the form of a triangle. It can be used both as a boundary object for continuously opening up more plural perspectives in the creation of desirable nature scenarios and as an actionable framework for developing consistent nature scenarios across multiple scales.Here we describe the methods employed to develop the NFF and how it fits into a longer term process to create transformative, multiscale scenarios for nature. We argue that the contribution of the NFF is twofold: (a) its ability to hold a plurality of perspectives on what is desirable, which enables the development of joint goals and visions and recognizes the possible convergence and synergies of measures to achieve these visions and (b), its multiscale functionality for elaborating scenarios and models that can inform decision‐making at relevant levels, making it applicable across specific places and perspectives on nature.If humanity is to achieve its goal of a more sustainable and prosperous future rooted in a flourishing nature, it is critical to open up a space for more plural perspectives of human–nature relationships. As the global community sets out to develop new goals for biodiversity, the NFF can be used as a navigation tool helping to make diverse, desirable futures possibl

    Visions for nature and nature’s contributions to people for the 21st century : Report from an IPBES visioning workshop held on 4-8 September 2017 in Auckland, New Zealand

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    Existing scenarios of biodiversity and ecosystem services (BES) have important limitations and gaps that constrain their usefulness for the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES). Specifically, they fail to incorporate policy objectives related to nature conservation and social-ecological feedbacks, they do not address the linkages between biodiversity and ecosystem services, and they are typically relevant at only a particular spatial scale. In addition, nature and its benefits are treated as the consequence of human decisions, but are not at the centre of the analysis. To address these issues, the IPBES Scenarios and Models Expert Group initiated the development of a set of Multiscale Scenarios for Nature Futures based on positive visions for human relationships with nature.The first step of this process was a visioning workshop with stakeholders and experts on 4-8 September 2017 in Auckland, New Zealand. A total of 73 participants from inter-governmental organisations, national government organisations, non-governmental organisations, academia and the private sector, from 31 countries, and with a range of sectoral expertise on biodiversity topics, from urban development to agriculture to fisheries, worked together in a visioning exercise. This report documents the results from this visioning workshop to inform further stakeholder consultation and the development of the associated multiscale scenarios by modelers and experts. This creative visioning exercise was carried out in four steps based on a suite of participatory methods that were used to develop visions of alternative futures. First the participants identified important themes to develop the visions. Next, thematic groups identified the main trends for BES in each theme and a set of “Seeds” of emerging initiatives leading to positive futures for our relationship with nature. Implications of what would happen across a range of sectors were identified for each seed. Then a pathway analysis of how the current regime in each theme may be transformed into the future desirable regime was carriedout. Narratives were then built for the visions emerging from each group. Finally, commonalities of visions across the groups were identified, and the regional relevance of each vision for different parts of the world was assessed

    Visions for nature and nature’s contributions to people for the 21st century : Report from an IPBES visioning workshop held on 4-8 September 2017 in Auckland, New Zealand

    No full text
    Existing scenarios of biodiversity and ecosystem services (BES) have important limitations and gaps that constrain their usefulness for the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES). Specifically, they fail to incorporate policy objectives related to nature conservation and social-ecological feedbacks, they do not address the linkages between biodiversity and ecosystem services, and they are typically relevant at only a particular spatial scale. In addition, nature and its benefits are treated as the consequence of human decisions, but are not at the centre of the analysis. To address these issues, the IPBES Scenarios and Models Expert Group initiated the development of a set of Multiscale Scenarios for Nature Futures based on positive visions for human relationships with nature.The first step of this process was a visioning workshop with stakeholders and experts on 4-8 September 2017 in Auckland, New Zealand. A total of 73 participants from inter-governmental organisations, national government organisations, non-governmental organisations, academia and the private sector, from 31 countries, and with a range of sectoral expertise on biodiversity topics, from urban development to agriculture to fisheries, worked together in a visioning exercise. This report documents the results from this visioning workshop to inform further stakeholder consultation and the development of the associated multiscale scenarios by modelers and experts. This creative visioning exercise was carried out in four steps based on a suite of participatory methods that were used to develop visions of alternative futures. First the participants identified important themes to develop the visions. Next, thematic groups identified the main trends for BES in each theme and a set of “Seeds” of emerging initiatives leading to positive futures for our relationship with nature. Implications of what would happen across a range of sectors were identified for each seed. Then a pathway analysis of how the current regime in each theme may be transformed into the future desirable regime was carriedout. Narratives were then built for the visions emerging from each group. Finally, commonalities of visions across the groups were identified, and the regional relevance of each vision for different parts of the world was assessed

    BioTIME:a database of biodiversity time series for the Anthropocene

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    Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community led open-source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal patterns of biodiversity in the Anthropocene.Main types of variables included: The database contains 8,777,413 species abundance records, from assemblages consistently sampled for a minimum of two, which need not necessarily be consecutive. In addition, the database contains metadata relating to sampling methodology andcontextual information about each record.Spatial location and grain: BioTIME is a global database of 547,161 unique sampling locations spanning the marine, freshwater and terrestrial realms. Grain size varies across datasets from 0.0000000158 km2 (158 cm2) to 100 km2 (1 000 000 000 000 cm2).Time period and grain: BioTIME records span from 1874 to 2016. The minimum temporal grain across all datasets in BioTIME is year.Major taxa and level of measurement: BioTIME includes data from 44,440 species across the plant and animal kingdoms, ranging from plants, plankton, and terrestrial invertebrates to small and large vertebrates.Software format: .csv and .SQ

    The Pierre Auger Observatory: Contributions to the 35th International Cosmic Ray Conference (ICRC 2017)

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    Observation of inclined EeV air showers with the radio detector of the Pierre Auger Observatory

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    International audienceWith the Auger Engineering Radio Array (AERA) of the Pierre Auger Observatory, we have observed the radio emission from 561 extensive air showers with zenith angles between 60o and 84o. In contrast to air showers with more vertical incidence, these inclined air showers illuminate large ground areas of several km2 with radio signals detectable in the 30 to 80 MHz band. A comparison of the measured radio-signal amplitudes with Monte Carlo simulations of a subset of 50 events for which we reconstruct the energy using the Auger surface detector shows agreement within the uncertainties of the current analysis. As expected for forward-beamed radio emission undergoing no significant absorption or scattering in the atmosphere, the area illuminated by radio signals grows with the zenith angle of the air shower. Inclined air showers with EeV energies are thus measurable with sparse radio-antenna arrays with grid sizes of a km or more. This is particularly attractive as radio detection provides direct access to the energy in the electromagnetic cascade of an air shower, which in case of inclined air showers is not accessible by arrays of particle detectors on the ground

    An Indication of anisotropy in arrival directions of ultra-high-energy cosmic rays through comparison to the flux pattern of extragalactic gamma-ray sources

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    International audienceA new analysis of the data set from the Pierre Auger Observatory provides evidence for anisotropy in the arrival directions of ultra-high-energy cosmic rays on an intermediate angular scale, which is indicative of excess arrivals from strong, nearby sources. The data consist of 5514 events above with zenith angles up to 80° recorded before 2017 April 30. Sky models have been created for two distinct populations of extragalactic gamma-ray emitters: active galactic nuclei from the second catalog of hard Fermi-LAT sources (2FHL) and starburst galaxies from a sample that was examined with Fermi-LAT. Flux-limited samples, which include all types of galaxies from the Swift-BAT and 2MASS surveys, have been investigated for comparison. The sky model of cosmic-ray density constructed using each catalog has two free parameters, the fraction of events correlating with astrophysical objects, and an angular scale characterizing the clustering of cosmic rays around extragalactic sources. A maximum-likelihood ratio test is used to evaluate the best values of these parameters and to quantify the strength of each model by contrast with isotropy. It is found that the starburst model fits the data better than the hypothesis of isotropy with a statistical significance of 4.0σ, the highest value of the test statistic being for energies above . The three alternative models are favored against isotropy with 2.7σ–3.2σ significance. The origin of the indicated deviation from isotropy is examined and prospects for more sensitive future studies are discussed

    Spectral Calibration of the Fluorescence Telescopes of the Pierre Auger Observatory

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    International audienceWe present a novel method to measure precisely the relative spectral response of the fluorescence telescopes of the Pierre Auger Observatory. We used a portable light source based on a xenon flasher and a monochromator to measure the relative spectral efficiencies of eight telescopes in steps of 5 nm from 280 nm to 440 nm. Each point in a scan had approximately 2 nm FWHM out of the monochromator. Different sets of telescopes in the observatory have different optical components, and the eight telescopes measured represent two each of the four combinations of components represented in the observatory. We made an end-to-end measurement of the response from different combinations of optical components, and the monochromator setup allowed for more precise and complete measurements than our previous multi-wavelength calibrations. We find an overall uncertainty in the calibration of the spectral response of most of the telescopes of 1.5% for all wavelengths; the six oldest telescopes have larger overall uncertainties of about 2.2%. We also report changes in physics measurables due to the change in calibration, which are generally small
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