258 research outputs found

    Synthetic Mudscapes: Human Interventions in Deltaic Land Building

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    In order to defend infrastructure, economy, and settlement in Southeast Louisiana, we must construct new land to mitigate increasing risk. Links between urban environments and economic drivers have constrained the dynamic delta landscape for generations, now threatening to undermine the ecological fitness of the entire region. Static methods of measuring, controlling, and valuing land fail in an environment that is constantly in flux; change and indeterminacy are denied by traditional inhabitation. Multiple land building practices reintroduce deltaic fluctuation and strategic deposition of fertile material to form the foundations of a multi-layered defence strategy. Manufactured marshlands reduce exposure to storm surge further inland. Virtual monitoring and communication networks inform design decisions and land use becomes determined by its ecological health. Mudscapes at the threshold of land and water place new value on former wastelands. The social, economic, and ecological evolution of the region are defended by an expanded web of growing land

    Diffuse inverse Compton and synchrotron emission from dark matter annihilations in galactic satellites

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    Annihilating dark matter particles produce roughly as much power in electrons and positrons as in gamma ray photons. The charged particles lose essentially all of their energy to inverse Compton and synchrotron processes in the galactic environment. We discuss the diffuse signature of dark matter annihilations in satellites of the Milky Way (which may be optically dark with few or no stars), providing a tail of emission trailing the satellite in its orbit. Inverse Compton processes provide X-rays and gamma rays, and synchrotron emission at radio wavelengths might be seen. We discuss the possibility of detecting these signals with current and future observations, in particular EGRET and GLAST for the gamma rays.Comment: 13 pages, 5 figure

    Nonpropagation of massive mode on AdS2 in topologically massive gravity

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    Making use of Achucarro-Ortiz (AO) type of dimensional reduction, we study the topologically massive gravity with a negative cosmological constant on AdS2 spacetimes. For a constant dilaton, this two-dimensional model also admits three AdS2 vacuum solutions, which are related to two AdS3 and warped AdS3 backgrounds with an identification upon uplifting three dimensions. We carry out the perturbation analysis around these backgrounds to find what is a physically propagating field. However, it turns out that there is no propagating massive mode on AdS2 background, in contrast to the Kaluza-Klein (KK) type of dimensional reduction. We note that two dimensionally reduced actions are different and thus, the non-equivalence of their on-shell amplitudes is obtained.Comment: 19 pages, version to appear in EPJ

    Topologically massive gravity on AdS2_2 spacetimes

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    We study the topologically massive gravity with a negative cosmological constant on AdS2_2 spacetimes by making use of dimensional reduction. For a constant dilaton, this two-dimensional model admits three AdS2_2 vacuum solutions, which are related to AdS3_3 and warped AdS3_3 with an identification upon uplifting three dimensions. We carry out the perturbation analysis around these backgrounds to find what is a physically propagating field. It turns out that a mode of δF=(hf/e)\delta F = (h-f/e) is merely a redundant field of dilaton φ\varphi in the absence of Chern-Simons terms, while it becomes a massive scalar in the presence of Chern-Simons terms. This shows clearly that the proper number of physically propagating degrees of freedom is one for the topologically massive gravity. Moreover, at the points of K=l,l/3K=l,l/3, δF\delta F becomes a massless scalar which implies that there is no physically propagating degrees of freedom at the chiral point.Comment: 24 pages, 3 figures, added appendix, version to appear in JHE

    Toward a Multifaceted Heuristic of Digital Reading to Inform Assessment, Research, Practice, and Policy

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    In this commentary, the author explores the tension between almost 30 years of work that has embraced increasingly complex conceptions of digital reading and recent studies that risk oversimplifying digital reading as a singular entity analogous with reading text on a screen. The author begins by tracing a line of theoretical and empirical work that both informs and complicates our understanding of digital literacy and, more specifically, digital reading. Then, a heuristic is proposed to systematically organize, label, and define a multifaceted set of increasingly complex terms, concepts, and practices that characterize the spectrum of digital reading experiences. Research that informs this heuristic is used to illustrate how more precision in defining digital reading can promote greater clarity across research methods and advance a more systematic study of promising digital reading practices. Finally, the author discusses implications for assessment, research, practice, and policy

    Obtention and characterization of coconut babassu derivatives

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    Babassu (Orbignya sp.) is a palm with extraordinary socioeconomic and ecologic importance found in humid tropical areas in Brazil, especially in frequently burned and degraded landscapes. There are several uses for babassu oil; however, its potential for providing other industrial products remains unexploited, due to the lack of scale and production structure. Oil and presscake extracted from kernels are industrially produced, while the remaining parts of the babassu coconut have the potential to add value as byproducts. This study aimed to establish conditions for the preparation of the raw material fruit of babassu for oil extraction by pressing and producing biodiesel by ethanolic transesterification. Babassu coconuts were dried at 75 and 90 °C. The separation of the fractions rich in fiber, starch, kernel and mesocarp was performed in appropriate equipments. The starch content in the mesocarp fractions of babassu coconuts dried at 75 and at 90 °C were 54 and 56 %, respectively and lipids represented 65 % of the kernel. Oil and press cake were obtained through hydraulic and continuous press, biodiesel was produced and the quality of products was compared. The total of saturated fatty acid in babassu oil was between 78 and 82 %, and the total of unsaturated fatty acids that promote good oxidative stability in the oil was in the range of 17 to 20 %. Oil obtained by cold pressing extraction and its biodiesel had better results in terms of quality. The quality of oils is within the Codex standard and biodiesel from oil extracted by cold pressing had higher oxidative stability

    Application of a risk-management framework for integration of stromal tumor-infiltrating lymphocytes in clinical trials

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    Stromal tumor-infiltrating lymphocytes (sTILs) are a potential predictive biomarker for immunotherapy response in metastatic triple-negative breast cancer (TNBC). To incorporate sTILs into clinical trials and diagnostics, reliable assessment is essential. In this review, we propose a new concept, namely the implementation of a risk-management framework that enables the use of sTILs as a stratification factor in clinical trials. We present the design of a biomarker risk-mitigation workflow that can be applied to any biomarker incorporation in clinical trials. We demonstrate the implementation of this concept using sTILs as an integral biomarker in a single-center phase II immunotherapy trial for metastatic TNBC (TONIC trial, NCT02499367), using this workflow to mitigate risks of suboptimal inclusion of sTILs in this specific trial. In this review, we demonstrate that a web-based scoring platform can mitigate potential risk factors when including sTILs in clinical trials, and we argue that this framework can be applied for any future biomarker-driven clinical trial setting
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