44,871 research outputs found

    Acoustic Kappa-Density Fluctuation Waves in Suprathermal Kappa Function Fluids

    Full text link
    We describe a new wave mode similar to the acoustic wave in which both density and velocity fluctuate. Unlike the acoustic wave in which the underlying distribution is Maxwellian, this new wave mode occurs when the underlying distribution is a suprathermal kappa function and involves fluctuations in the power law index, kappa. This wave mode always propagates faster than the acoustic wave with an equivalent effective temperature and becomes the acoustic wave in the Maxwellian limit as kappa goes to infinity.Comment: 11 pages, 2 figures, in press AS

    One-Up On L1: Can X-rays Provide Longer Advanced Warning of Solar Wind Flux Enhancements Than Upstream Monitors?

    Full text link
    Observations of strong solar wind proton flux correlations with ROSAT X-ray rates along with high spectral resolution Chandra observations of X-rays from the dark Moon show that soft X-ray emission mirrors the behavior of the solar wind. In this paper, based on an analysis of an X-ray event observed by XMM-Newton resulting from charge exchange of high charge state solar wind ions and contemporaneous neutral solar wind data, we argue that X-ray observations may be able to provide reliable advance warning, perhaps by as much as half a day, of dramatic increases in solar wind flux at Earth. Like neutral atom imaging, this provides the capability to monitor the solar wind remotely rather than in-situ.Comment: in press in Adv. Space Research, 7 pages, 6 eps figures, resolution reduced for Astro-ph submission, see http://lena.gsfc.nasa.gov for full versio

    Schizophrenia in older adults

    Get PDF
    Although the number of persons over the age of 55 with schizophrenia is expected to double over the next 20 years, the research data on older people with schizophrenia is limited. This appears to be because until the middle of the 20th century, it was assumed that mental illness in older people was a part of the aging process and older people are often excluded from research investigations. There is a need for nursing research to explore how people with schizophrenia, as they age, learn to manage their problems, as well as how those who are first diagnosed with schizophrenia in later life adapt to their illness. Mental health nurses need to be cautious in assigning premature labels to older adults with mental illness that may lead to unsubstantiated assumptions about levels of disability. Instead, they should realize individual potential regarding undiscovered strengths and should attempt to create interventions that recognize and foster personal development for older adults with schizophrenia

    What is Autonomy?

    Get PDF
    A system is autonomous if it uses its own information to modify itself and its environment to enhance its survival, responding to both environmental and internal stimuli to modify its basic functions to increase its viability. Autonomy is the foundation of functionality, intentionality and meaning. Autonomous systems accommodate the unexpected through self-organizing processes, together with some constraints that maintain autonomy. Early versions of autonomy, such as autopoiesis and closure to efficient cause, made autonomous systems dynamically closed to information. This contrasts with recent work on open systems and information dynamics. On our account, autonomy is a matter of degree depending on the relative organization of the system and system environment interactions. A choice between third person openness and first person closure is not required

    Storage of Natural Language Sentences in a Hopfield Network

    Full text link
    This paper look at how the Hopfield neural network can be used to store and recall patterns constructed from natural language sentences. As a pattern recognition and storage tool, the Hopfield neural network has received much attention. This attention however has been mainly in the field of statistical physics due to the model's simple abstraction of spin glass systems. A discussion is made of the differences, shown as bias and correlation, between natural language sentence patterns and the randomly generated ones used in previous experiments. Results are given for numerical simulations which show the auto-associative competence of the network when trained with natural language patterns.Comment: latex, 10 pages with 2 tex figures and a .bib file, uses nemlap.sty, to appear in Proceedings of NeMLaP-

    What's unusual in online disease outbreak news?

    Get PDF
    Background: Accurate and timely detection of public health events of international concern is necessary to help support risk assessment and response and save lives. Novel event-based methods that use the World Wide Web as a signal source offer potential to extend health surveillance into areas where traditional indicator networks are lacking. In this paper we address the issue of systematically evaluating online health news to support automatic alerting using daily disease-country counts text mined from real world data using BioCaster. For 18 data sets produced by BioCaster, we compare 5 aberration detection algorithms (EARS C2, C3, W2, F-statistic and EWMA) for performance against expert moderated ProMED-mail postings. Results: We report sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), mean alerts/100 days and F1, at 95% confidence interval (CI) for 287 ProMED-mail postings on 18 outbreaks across 14 countries over a 366 day period. Results indicate that W2 had the best F1 with a slight benefit for day of week effect over C2. In drill down analysis we indicate issues arising from the granular choice of country-level modeling, sudden drops in reporting due to day of week effects and reporting bias. Automatic alerting has been implemented in BioCaster available from http://born.nii.ac.jp. Conclusions: Online health news alerts have the potential to enhance manual analytical methods by increasing throughput, timeliness and detection rates. Systematic evaluation of health news aberrations is necessary to push forward our understanding of the complex relationship between news report volumes and case numbers and to select the best performing features and algorithms

    The Natural Foundations of Religion

    Get PDF
    In the Natural history of religion, Hume attempts to understand the origin of our folk belief in gods and spirits. These investigations are not, however, purely descriptive. Hume demonstrates that ontological commitment to supernatural agents depends on motivated reasoning and illusions of control. These beliefs cannot, then, be reflectively endorsed. This proposal must be taken seriously because it receives support from recent work on our psychological responses to uncertainty. It also compares quite favorably with its main competitors in the cognitive science of religio

    Taken

    Get PDF
    • …
    corecore