3,717 research outputs found

    Interior perfect fluid scalar-tensor solution

    Full text link
    We present a new exact perfect fluid interior solution for a particular scalar-tensor theory. The solution is regular everywhere and has a well defined boundary where the fluid pressure vanishes. The metric and the dilaton field match continuously the external solution.Comment: 8 pages, 3 figures, LaTe

    EU Nature Restoration Law; EGU Response

    Get PDF
    The EGU Biodiversity Task Force welcomes the ambitious targets outlined in the Nature Restoration Law that was presented by the European Commission on 22 June 2022. To ensure the Nature Restoration Law is successful, the EGU Biodiversity Task Force is recommending seven key points to be added, amended, or strengthened throughout the document

    Sustainable Forest Bioenergy Development Strategies in Indochina: Collaborative Effort to Establish Regional Policies

    Get PDF
    We conducted a feasibility study in Indochina (Cambodia, Laos, Myanmar, Thailand, and Vietnam) with the aim of promoting biomass and bioenergy markets, technology transfer, rural development, and income generation. Policy development is guided by the International Union of Forest Research Institutions (IUFRO) Task Force “Sustainable Forest Bioenergy Network”. In this paper, we highlight the achievements up to now and present results of a multi-stakeholder questionnaire in combination with a quantitative analysis of the National Bioenergy Development Plans (NBDPs). We found a gap between official documents and working group assessments. NBDPs are focused on the market development, technology transfer, and funding possibilities of a regional bioenergy strategy, while the respondents of a questionnaire (working groups) favored more altruistic goals, i.e., sustainable resource management, environmental protection and climate change mitigation, generation of rural income, and community involvement, etc. We therefore suggest the following measures to ensure regulations that support the original aims of the network (climate change mitigation, poverty alleviation, sustainable resource use, and diversification of energy generation): (i) Consideration of science-based evidence for drafting bioenergy policies, particularly in the field of biomass production and harvesting; (ii) invitation of stakeholders representing rural communities to participate in this process; (iii) development of sustainability criteria; (iv) feedback cycles ensuring more intensive discussion of policy drafts; (v) association of an international board of experts to provide scientifically sound feedback and input; and (vi) establishment of a local demonstration region, containing various steps in the biomass/bioenergy supply chain including transboundary collaboration in the ACMECS region

    ACMECS Bioenergy 2015. Three Years of Effort Towards a Regional Bioenergy Network

    Get PDF
    Global change, including climate change, societal dynamics, economic challenges, environmental protection and the need to improve livelihoods and to reduce poverty have led to a situation where national solutions must be embedded in regional strategies. The ACMECS countries Lao PDR, Cambodia, Myanmar, Thailand and Vietnam have a long tradition in collaboration across borders. Despite the cultural heterogeneity and different status of development, it can be a great advantage to address global challenges together. Biomass is seen as a promising resource for energy and industrial raw materials, but the challenge is that biomass production requires land and increased production can cause conflicts and environmental degradation. The increased demand for biomass in the recent years, coupled with the fact that the balance between domestic, regional and foreign demand for biomass is changing, requires careful attention. As a consequence of these developments, the Kasetsart Agricultural and Agro-Industrial Product Improvement Institute (KAPI) of the Kasetsart University, Thailand initiated a process to establish a regional bioenergy network. International experts, including members of the IUFRO Task Force "Sustainable Forest Biomass Network (SFBN)", have acknowledged the significant progress made over the last few years. This report is jointly published with the IUFRO Occasional Paper series, Vol. 31 (http://www.iufro.org/publications/series/occasional-papers/article/2016/04/20/occasional-paper-31-acmecs-bioenergy-2015-three-years-of-efforts-towards-a-regional-bioenergy-n/

    Thirty-two Goldbach Variations

    Full text link
    We give thirty-two diverse proofs of a small mathematical gem--the fundamental Euler sum identity zeta(2,1)=zeta(3) =8zeta(\bar 2,1). We also discuss various generalizations for multiple harmonic (Euler) sums and some of their many connections, thereby illustrating both the wide variety of techniques fruitfully used to study such sums and the attraction of their study.Comment: v1: 34 pages AMSLaTeX. v2: 41 pages AMSLaTeX. New introductory material added and material on inequalities, Hilbert matrix and Witten zeta functions. Errors in the second section on Complex Line Integrals are corrected. To appear in International Journal of Number Theory. Title change

    The ATLAS SCT grounding and shielding concept and implementation

    Get PDF
    This paper presents a complete description of Virgo, the French-Italian gravitational wave detector. The detector, built at Cascina, near Pisa (Italy), is a very large Michelson interferometer, with 3 km-long arms. In this paper, following a presentation of the physics requirements, leading to the specifications for the construction of the detector, a detailed description of all its different elements is given. These include civil engineering infrastructures, a huge ultra-high vacuum (UHV) chamber (about 6000 cubic metres), all of the optical components, including high quality mirrors and their seismic isolating suspensions, all of the electronics required to control the interferometer and for signal detection. The expected performances of these different elements are given, leading to an overall sensitivity curve as a function of the incoming gravitational wave frequency. This description represents the detector as built and used in the first data-taking runs. Improvements in different parts have been and continue to be performed, leading to better sensitivities. These will be detailed in a forthcoming paper

    Participant Perceptions of Twitter Research Ethics

    Get PDF
    Social computing systems such as Twitter present new research sites that have provided billions of data points to researchers. However, the availability of public social media data has also presented ethical challenges. As the research community works to create ethical norms, we should be considering users’ concerns as well. With this in mind, we report on an exploratory survey of Twitter users’ perceptions of the use of tweets in research. Within our survey sample, few users were previously aware that their public tweets could be used by researchers, and the majority felt that researchers should not be able to use tweets without consent. However, we find that these attitudes are highly contextual, depending on factors such as how the research is conducted or disseminated, who is conducting it, and what the study is about. The findings of this study point to potential best practices for researchers conducting observation and analysis of public data
    • 

    corecore