281,564 research outputs found

    Calibrating pressure switch

    Get PDF
    A pressure switch assembly comprising a body portion and a switch mechanism having a contact element operable between opposite limit positions is described. A diaphragm chamber is provided in the body portion which mounts therein a system diaphragm and a calibration diaphragm which are of generally the same configuration and having outer faces conforming to the inner and outer walls of the diaphragm chamber. The space between the inner faces of the diaphragms defines a first chamber section and the space between the outer face of one of the diaphragms and the outer wall of the diaphragm chamber defines a second chamber section. The body portion includes a system pressure port communicating with one of the chamber sections and a calibration pressure port communicating with the other chamber section. An actuator connected to one of the diaphragms and the contact element of the switch operates upon pressure change in the diaphragm sections to move said contact element between limit positions

    Chernobyl: catastrophe and consequences

    Get PDF

    Truth, Lies, and Copyright

    Get PDF
    Fake news may be trending right now, but fake news is not the only source of fake facts that we consume. We encounter fake facts every day in the historical or biographical books we read, the movies we watch, the maps we study, the tele-phone directories and dictionaries we reference, and the religious or spiritual guides we consult. While it is well-established that copyright does not protect facts because facts are discovered rather than created, fake facts are created and can often be as original and creative as fiction. This Article is the first to offer a comprehensive analysis of copyright protection of fake facts contained in fake news and other sources. It details the different categories of fake facts we encounter today and courts’ inconsistent protection of fake facts under copyright law. Even though copyright law may technically protect fake facts as original expression fixed in a tangible medium, this Article argues that the public interest in promoting efficiency, fairness, and production of socially valuable works justify treating fake facts as unprotectable facts under copyright law. Specifically, courts should apply copyright law’s factual estoppel doctrine to treat fake facts as unprotectable facts in infringement cases where an author previously held out fake facts as facts, with the intent that the public rely on the fake facts as facts, if the public could believe the fake facts to be true

    The influence of linguistic and social factors on the recent decline of French ne

    Get PDF
    In this article we present some results showing the decline in radio speech in the use of the French negative particle ne over the last forty years or so. These results derive from a comparison of two radio corpora: an archival corpus recorded by Ågren (1973) in 1960–61. The second, contemporary corpus was recorded and analysed by one of the present authors (Smith) in 1997. Having described the variable in question, we present these corpora in turn and analyse results deriving from them. We then examine some of the linguistic constraints that endorse the progressive decline of ne in some contexts while hindering the process in others. Finally we consider some elements of the social context within which the decline of ne has been occurring

    Nose inlets

    Get PDF

    Air inlets

    Get PDF

    Interacting Supernovae: Types IIn and Ibn

    Full text link
    Supernovae (SNe) that show evidence of strong shock interaction between their ejecta and pre-existing, slower circumstellar material (CSM) constitute an interesting, diverse, and still poorly understood category of explosive transients. The chief reason that they are extremely interesting is because they tell us that in a subset of stellar deaths, the progenitor star may become wildly unstable in the years, decades, or centuries before explosion. This is something that has not been included in standard stellar evolution models, but may significantly change the end product and yield of that evolution, and complicates our attempts to map SNe to their progenitors. Another reason they are interesting is because CSM interaction is an efficient engine for making bright transients, allowing super-luminous transients to arise from normal SN explosion energies, and allowing transients of normal SN luminosities to arise from sub-energetic explosions or low radioactivity yield. CSM interaction shrouds the fast ejecta in bright shock emission, obscuring our normal view of the underlying explosion, and the radiation hydrodynamics of the interaction is challenging to model. The CSM interaction may also be highly non-spherical, perhaps linked to binary interaction in the progenitor system. In some cases, these complications make it difficult to definitively tell the difference between a core-collapse or thermonuclear explosion, or to discern between a non-terminal eruption, failed SN, or weak SN. Efforts to uncover the physical parameters of individual events and connections to possible progenitor stars make this a rapidly evolving topic that continues to challenge paradigms of stellar evolution.Comment: Final draft of a chapter in the "SN Handbook". Accepted. 25 pages, 3 fig

    A Census of the Carina Nebula -- II. Energy Budget and Global Properties of the Nebulosity

    Full text link
    The first paper in this series took a direct census of energy input from the known OB stars in the Carina Nebula, and in this paper we study the global properties of the surrounding nebulosity. We find that the total IR luminosity of Carina is about 1.2E7 Lsun, accounting for only about 50-60% of the known stellar luminosity from Paper I. Similarly, the ionizing photon luminosity -- (abridged; many important details omitted). Synchronized star formation around the periphery of Carina provides a strong case that star formation here was indeed triggered by stellar winds and UV radiation. This second generation appears to involve a cascade toward preferentially intermediate- and low-mass stars, but this may soon change when eta Car and its siblings explode. If the current reservoir of atomic and molecular gas can be tapped at that time, massive star formation may be rejuvinated around the periphery of Carina much as if it were a young version of Gould's Belt. Also, when these multiple SNe occur, the triggered second generation will be pelted repeatedly with SN ejecta bearing short-lived radioactive nuclides. Carina may therefore represent the most observable analog to the cradle of our own Solar System.Comment: MNRAS accepted, 14 pages, fig 1 in colo

    Empirical Risk Minimization for Probabilistic Grammars: Sample Complexity and Hardness of Learning

    Get PDF
    Probabilistic grammars are generative statistical models that are useful for compositional and sequential structures. They are used ubiquitously in computational linguistics. We present a framework, reminiscent of structural risk minimization, for empirical risk minimization of probabilistic grammars using the log-loss. We derive sample complexity bounds in this framework that apply both to the supervised setting and the unsupervised setting. By making assumptions about the underlying distribution that are appropriate for natural language scenarios, we are able to derive distribution-dependent sample complexity bounds for probabilistic grammars. We also give simple algorithms for carrying out empirical risk minimization using this framework in both the supervised and unsupervised settings. In the unsupervised case, we show that the problem of minimizing empirical risk is NP-hard. We therefore suggest an approximate algorithm, similar to expectation-maximization, to minimize the empirical risk. Learning from data is central to contemporary computational linguistics. It is in common in such learning to estimate a model in a parametric family using the maximum likelihood principle. This principle applies in the supervised case (i.e., using annotate
    corecore