1,397 research outputs found

    Follow Up of GW170817 and Its Electromagnetic Counterpart by Australian-Led Observing Programmes

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    The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in the new era of multi-messenger astronomy. In this paper, we present follow-up observations of the gravitational wave event GW170817 and its electromagnetic counterpart SSS17a/DLT17ck (IAU label AT2017gfo) by 14 Australian telescopes and partner observatories as part of Australian-based and Australian-led research programs. We report early- to late-time multi-wavelength observations, including optical imaging and spectroscopy, mid-infrared imaging, radio imaging, and searches for fast radio bursts. Our optical spectra reveal that the transient source emission cooled from approximately 6 400 K to 2 100 K over a 7-d period and produced no significant optical emission lines. The spectral profiles, cooling rate, and photometric light curves are consistent with the expected outburst and subsequent processes of a binary neutron star merger. Star formation in the host galaxy probably ceased at least a Gyr ago, although there is evidence for a galaxy merger. Binary pulsars with short (100 Myr) decay times are therefore unlikely progenitors, but pulsars like PSR B1534+12 with its 2.7 Gyr coalescence time could produce such a merger. The displacement (~2.2 kpc) of the binary star system from the centre of the main galaxy is not unusual for stars in the host galaxy or stars originating in the merging galaxy, and therefore any constraints on the kick velocity imparted to the progenitor are poor

    The Missing Dimensions of the Human Capabilities Approach: Collective and Productive

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    In this paper we identify two missing dimensions of the Human Capabilities Approach (HCA)—the collective and the productive—and in doing so we advance a ‘productionist’ perspective on development, centred around the idea of ‘collective productive capabilities’. Bringing production back to the core of the development agenda calls for an integration of the HCA and those contributions which have focused their attention on the social, economic and institutional processes of learning, centred around productive organisations and systems. The lack of this focus on collective productive capabilities undermined the Millenium Development Goals Agenda and is still having negative impacts on the ways in which the Sustainable Development Goals Agenda is understood and implemented

    Target of Opportunity Observations of Gravitational Wave Events with LSST

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    The discovery of the electromagnetic counterparts to the binary neutron star merger GW170817 has opened the era of GW+EM multi-messenger astronomy. Exploiting this breakthrough requires increasing samples to explore the diversity of kilonova behaviour and provide more stringent constraints on the Hubble constant, and tests of fundamental physics. LSST can play a key role in this field in the 2020s, when the gravitational wave detector network is expected to detect higher rates of merger events involving neutron stars (∼10s per year) out to distances of several hundred Mpc. Here we propose comprehensive target-of-opportunity (ToOs) strategies for follow-up of gravitational-wave sources that will make LSST the premiere machine for discovery and early characterization for neutron star mergers and other gravitational-wave sources

    Excludability: A laboratory study on forced ranking in team production

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    Exclusion has long been employed as a common disciplinary measure against defectors, both at work and in social life. In this paper, we study the effect of excludability - exclusion of the lowest contributor - on contributions in three different team production settings. We demonstrate theoretically and experimentally that excludability increases contributions. Excludability is particularly effective in production settings where the average or maximum effort determines team production. In these settings, we observe almost immediate convergence to full contribution. In settings where the minimum effort determines team production, excludability leads to a large increase in contributions only if the value of the excluded individual's contribution to the public good is redistributed among the included individuals

    Follow Up of GW170817 and Its Electromagnetic Counterpart by Australian-Led Observing Programmes

    Get PDF
    The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in the new era of multi-messenger astronomy. In this paper, we present follow-up observations of the gravitational wave event GW170817 and its electromagnetic counterpart SSS17a/DLT17ck (IAU label AT2017gfo) by 14 Australian telescopes and partner observatories as part of Australian-based and Australian-led research programs. We report early- to late-time multi-wavelength observations, including optical imaging and spectroscopy, mid-infrared imaging, radio imaging, and searches for fast radio bursts. Our optical spectra reveal that the transient source emission cooled from approximately 6 400 K to 2 100 K over a 7-d period and produced no significant optical emission lines. The spectral profiles, cooling rate, and photometric light curves are consistent with the expected outburst and subsequent processes of a binary neutron star merger. Star formation in the host galaxy probably ceased at least a Gyr ago, although there is evidence for a galaxy merger. Binary pulsars with short (100 Myr) decay times are therefore unlikely progenitors, but pulsars like PSR B1534+12 with its 2.7 Gyr coalescence time could produce such a merger. The displacement (~2.2 kpc) of the binary star system from the centre of the main galaxy is not unusual for stars in the host galaxy or stars originating in the merging galaxy, and therefore any constraints on the kick velocity imparted to the progenitor are poor

    Gravity and Light: Combining Gravitational Wave and Electromagnetic Observations in the 2020s

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    As of today, we have directly detected exactly one source in both gravitational waves (GWs) and electromagnetic (EM) radiation, the binary neutron star merger GW170817, its associated gamma-ray burst GRB170817A, and the subsequent kilonova SSS17a/AT 2017gfo. Within ten years, we will detect hundreds of events, including new classes of events such as neutron-star-black-hole mergers, core-collapse supernovae, and almost certainly something completely unexpected. As we build this sample, we will explore exotic astrophysical topics ranging from nucleosynthesis, stellar evolution, general relativity, high-energy astrophysics, nuclear matter, to cosmology. The discovery potential is extraordinary, and investments in this area will yield major scientific breakthroughs. Here we outline some of the most exciting scientific questions that can be answered by combining GW and EM observations

    Cost-effectiveness analysis of Vaborem in Carbapenem-resistant Enterobacterales (CRE) -Klebsiella pneumoniae infections in Italy

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    Background: Vaborem is a fixed dose combination of vaborbactam and meropenem with potent activity against target Carbapenem-resistant Enterobacterales (CRE) pathogens, optimally developed for Klebsiella pneumoniae carbapenemase (KPC). The study aims to evaluate the cost-effectiveness of Vaborem versus best available therapy (BAT) for the treatment of patients with CRE-KPC associated infections in the Italian setting. Methods: A cost-effectiveness analysis was conducted based on a decision tree model that simulates the clinical pathway followed by physicians treating patients with a confirmed CRE-KPC infection in a 5-year time horizon. The Italian National Health System perspective was adopted with a 3% discount rate. The clinical inputs were mostly sourced from the phase 3, randomised, clinical trial (TANGO II). Unit costs were retrieved from the Italian official drug pricing list and legislation, while patient resource use was validated by a national expert. Model outcomes included life years (LYs) and quality adjusted life years (QALYs) gained, incremental costs, incremental cost- effectiveness ratio (ICER) and incremental cost-utility ratio (ICUR). Deterministic and probabilistic sensitivity analyses were also performed. Results: Vaborem is expected to decrease the burden associated with treatment failure and reduce the need for chronic renal replacement therapy while costs related to drug acquisition and long-term care (due to higher survival) may increase. Treatment with Vaborem versus BAT leads to a gain of 0.475 LYs, 0.384 QALYs, and incremental costs of €3549, resulting in an ICER and ICUR of €7473/LY and €9246/QALY, respectively. Sensitivity analyses proved the robustness of the model and also revealed that the probability of Vaborem being cost-effective reaches 90% when willingness to pay is €15,850/QALY. Conclusions: In the Italian setting, the introduction of Vaborem will lead to a substantial increase in the quality of life together with a minimal cost impact, therefore Vaborem is expected to be a cost-effective strategy compared to BAT

    Global use of water resources: a multiregional analysis for Water Use, Water Footprint and Water Trade Balance

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    In this paper a multiregional input–output model is proposed and used to estimate time series trends for water use, water footprint and water trade balance. By using data provided by the World Input–Output Database, the water used in production, consumption and trade is quantified for 41 world regions between 1995 and 2008. Results show that global water use grew by 37.3%, with China, India and Brazil contributing most to that increase. China and India, together with the EU-27, were also responsible for the largest water footprint variations. In terms of trade, the EU-27 was the largest water importer and China and India the main water exporters. The results provided in this paper offer an overview of the main countries’ responsibility for the use of water resources. They provide a good starting point for international debates and policies on sustainable water use

    Global impacts of the automotive supply-demand chain disruption following the Japanese earthquake of 2011

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    This paper provides an input–output method to estimate worldwide economic impacts generated by supply chain disruptions. The method is used to analyse global economic effects due to the disruptions in the automotive industry that followed the Japanese earthquake and the consequent tsunami and nuclear crisis of March 2011. By combining a mixed multi-regional input–output model, the World Input–Output Database and data at the factory level, the study quantifies the economic impacts of the disruptions broken down by country and industry. The results show that the global economic effect (in terms of value added) of this disruption amounted to US$139 billion. The most affected (groups of) countries were Japan (39%), the USA (25%), China (8%) and the European Union (7%). The most strongly affected industries were transport equipment (37%), other business activities (10%), basic and fabricated metals (8%), wholesale trade (7%) and financial intermediation (4%)
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