2,467 research outputs found

    Debating evolutions in science, technology and society Ethical and ideological perspectives: An introduction

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    This article introduces the theme of the Special Issue on \u201cDebating evolutions in science, technology and society: Ethical and ideological perspectives.\u201d Its starts from the idea that new advances in science and in technology, new evolutions in society, politics and culture bring with them the need to update linguistic resources at different levels in order to be able to talk about them and accommodate new concepts. Thus they inevitably result in an impact on language and discourse that goes well beyond vocabulary and terminology. They change patterns of thinking, reasoning and conceptualizing, leading to new representations and new discourses. In particular, representation of evolutions in texts addressed to the general public involves the transfer of domain-specific knowledge to various non-specialist audiences and its recontextualization and transformation to be made accessible to the non-specialist. That is why it can never be neutral, even when the writer has the best intentions in terms of accuracy and honesty. The focus of this introductory article is in particular on the notion of discursive frame, frames being cognitive perceptual structures that either subconsciously or strategically influence participants on how to \u201chear or how to say\u201d something. It shows that framing, selecting and perspectivising are inevitable in knowledge dissemination and transmission, and argues that since they are so effective, discourse frames are a powerful ideological instrument, capable of influencing the public perception of the most crucial issues in society

    X-ray Observations of XSS J12270-4859 in a New Low State: A Transformation to a Disk-Free Rotation-Powered Pulsar Binary

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    We present XMM-Newton and Chandra observations of the low-mass X-ray binary XSS J12270--4859, which experienced a dramatic decline in optical/X-ray brightness at the end of 2012, indicative of the disappearance of its accretion disk. In this new state, the system exhibits previously absent orbital-phase-dependent, large-amplitude X-ray modulations with a decline in flux at superior conjunction. The X-ray emission remains predominantly non-thermal but with an order of magnitude lower mean luminosity and significantly harder spectrum relative to the previous high flux state. This phenomenology is identical to the behavior of the radio millisecond pulsar binary PSR J1023+0038 in the absence of an accretion disk, where the X-ray emission is produced in an intra-binary shock driven by the pulsar wind. This further demonstrates that XSS J12270-4859 no longer has an accretion disk and has transformed to a full-fledged eclipsing "redback" system that hosts an active rotation-powered millisecond pulsar. There is no evidence for diffuse X-ray emission associated with the binary that may arise due to outflows or a wind nebula. An extended source situated 1.5' from XSS J12270--4859 is unlikely to be associated, and is probably a previously uncatalogued galaxy cluster.Comment: 8 pages, 6 figures; accepted for publication in the Astrophysical Journa

    Plans for a Neutron EDM Experiment at SNS

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    The electric dipole moment of the neutron, leptons, and atoms provide a unique window to Physics Beyond the Standard Model. We are currently developing a new neutron EDM experiment (the nEDM Experiment). This experiment, which will be run at the 8.9 A Neutron Line at the Fundamental Neutron Physics Beamline (FNPB) at the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory, will search for the neutron EDM with a sensitivity two orders of magnitude better than the present limit. In this paper, the motivation for the experiment, the experimental method, and the present status of the experiment are discussed.Comment: 9 Pages, 4 Figures, submitted to the proceedings of the Second Meeting of the APS Topical Group on Hadronic Physics, Nashville, TN, October 22-24, 200

    Comment on ``Measurement of the 3^3He mass diffusion coefficient in superfluid 4^4He over the 0.45--0.95 K temperature range

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    The role of 3He-3He collisions in our diffusion experiment is addressed and shown to not be relevant to the measurement of 3He diffusion against phonons in superfluid helium.Comment: Two pages, in Europhysics Letters forma

    Binary evolution with LOFT

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    This is a White Paper in support of the mission concept of the Large Observatory for X-ray Timing (LOFT), proposed as a medium-sized ESA mission. We discuss the potential of LOFT for the study of very faint X-ray binaries, orbital period distribution of black hole X-ray binaries and neutron star spin up. For a summary, we refer to the paper.Comment: White Paper in Support of the Mission Concept of the Large Observatory for X-ray Timing. (v2 few typos corrected

    Synthesis of HDAC substrate peptidomimetic inhibitors (SPIs) using Fmoc amino acids incorporating zinc-binding groups

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    Syntheses of Fmoc amino acids having zinc-binding groups were prepared and incorporated into substrate inhibitor H3K27 peptides using Fmoc/tBu solid-phase peptide synthesis (SPPS). Peptide 11, prepared using Fmoc-Asu(NHOtBu)-OH, is a potent inhibitor (IC50 = 390 nM) of the core NuRD corepressor complex (HDAC1ā€“MTA1ā€“RBBP4). The Fmoc amino acids have the potential to facilitate the rapid preparation of substrate peptidomimetic inhibitor (SPI) libraries in the search for selective HDAC inhibitors

    Measurement of the 3He mass diffusion coefficient in superfluid 4He over the 0.45-0.95 K temperature range

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    We have measured the mass diffusion coefficient D of 3He in superfluid 4He at temperatures lower than were previously possible. The experimental technique utilizes scintillation light produced when neutron react with 3He nuclei, and allows measurement of the 3He density integrated along the trajectory of a well-defined neutron beam. By measuring the change in 3He density near a heater as a function of applied heat current, we are able to infer values of D with 20% accuracy. At temperatures below 0.7 K and for concentrations of order 10^{-4} we find D=(2.0+2.4-1.2)T^-(6.5 -/+ 1.2) cm^2/s, in agreement with a theoretical approximation.Comment: 8 pages, 5 figures. Submitted to Europhysics Letters and prepared in that journal's forma
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