21,757 research outputs found

    A contingent value? The changing role of autonomy in law and policy on AIDS

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    This essay examines the changing role of the ethical value of autonomy in law and policy relating to AIDS in a number of European jurisdictions. In the early years of the epidemic the autonomy of infected and at-risk persons, and of social groups was promoted as a means of reducing the spread of HIV in the general population. Accordingly autonomy was deemed worthy of respect for instrumental reasons. This means-end calculation was premised on the lack of medical therapies, as well as the need to avoid discrimination in order to prevent at-risk persons from going underground as far as health care systems were concerned. In law this instrumentalisation of autonomy was reflected in a specific application of the proportionality test, i.e. to impose coercive or discriminatory measures would be disproportionate, or even inimical, to the end of reducing the spread of HIV. This was a contingent analysis, strongly informed by the state of medical knowledge at the time, as well as by the relative power of professionals, health bureaucrats and lay activists. With the introduction of effective therapies such as Highly Active Retroviral Therapy (HAART) and Zidovudine (AZT) the terms of the proportionality analysis have changed decisively. As a result, it is now more likely than before that coercive measures will be implemented. --

    Reduction of dimension for nonlinear dynamical systems

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    We consider reduction of dimension for nonlinear dynamical systems. We demonstrate that in some cases, one can reduce a nonlinear system of equations into a single equation for one of the state variables, and this can be useful for computing the solution when using a variety of analytical approaches. In the case where this reduction is possible, we employ differential elimination to obtain the reduced system. While analytical, the approach is algorithmic, and is implemented in symbolic software such as {\sc MAPLE} or {\sc SageMath}. In other cases, the reduction cannot be performed strictly in terms of differential operators, and one obtains integro-differential operators, which may still be useful. In either case, one can use the reduced equation to both approximate solutions for the state variables and perform chaos diagnostics more efficiently than could be done for the original higher-dimensional system, as well as to construct Lyapunov functions which help in the large-time study of the state variables. A number of chaotic and hyperchaotic dynamical systems are used as examples in order to motivate the approach.Comment: 16 pages, no figure

    Multi-wavelength Signatures of Cosmic Rays in the Milky Way

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    Cosmic rays (CRs) propagate in the Milky Way and interact with the interstellar medium and magnetic fields. These interactions produce emissions that span the electromagnetic spectrum, and are an invaluable tool for understanding the intensities and spectra of CRs in distant regions, far beyond those probed by direct CR measurements. We present updates on the study of CR properties by combining multi-frequency observations of the interstellar emission and latest CR direct measurements with propagation models.Comment: 8 pages, 4 figures. Proceedings of the 35th International Cosmic Ray Conference, ICRC201

    A Method To Remove Fringes From Images Using Wavelets

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    We have developed a new method that uses wavelet analysis to remove interference fringe patterns from images. This method is particularly useful for flat fields in the common case where fringes vary between the calibration and object data. We analyze the efficacy of this method by creating fake flats with fictitious fringes and removing the fringes. We find that the method removes 90% of the fringe pattern if its amplitude is equal to the random noise level and 60% if the fringe amplitude is ≈1/10\approx 1/10 of the noise level. We also present examples using real flat field frames. A routine written in the Interactive Data Language (IDL) that implements this algorithm is available from the authors and as an attachment to this paper.Comment: 7 pages, 14 figures. Accepted to the Astrophysical Journal. (The quality of the figures in this preprint has been downgraded in order to fulfill arXiv requirements. Check journal for the high-quality figures

    Persistent homology of time-dependent functional networks constructed from coupled time series

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    We use topological data analysis to study "functional networks" that we construct from time-series data from both experimental and synthetic sources. We use persistent homology with a weight rank clique filtration to gain insights into these functional networks, and we use persistence landscapes to interpret our results. Our first example uses time-series output from networks of coupled Kuramoto oscillators. Our second example consists of biological data in the form of functional magnetic resonance imaging (fMRI) data that was acquired from human subjects during a simple motor-learning task in which subjects were monitored on three days in a five-day period. With these examples, we demonstrate that (1) using persistent homology to study functional networks provides fascinating insights into their properties and (2) the position of the features in a filtration can sometimes play a more vital role than persistence in the interpretation of topological features, even though conventionally the latter is used to distinguish between signal and noise. We find that persistent homology can detect differences in synchronization patterns in our data sets over time, giving insight both on changes in community structure in the networks and on increased synchronization between brain regions that form loops in a functional network during motor learning. For the motor-learning data, persistence landscapes also reveal that on average the majority of changes in the network loops take place on the second of the three days of the learning process.Comment: 17 pages (+3 pages in Supplementary Information), 11 figures in many text (many with multiple parts) + others in SI, submitte

    The Complexity of Orbits of Computably Enumerable Sets

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    The goal of this paper is to announce there is a single orbit of the c.e. sets with inclusion, \E, such that the question of membership in this orbit is Σ11\Sigma^1_1-complete. This result and proof have a number of nice corollaries: the Scott rank of \E is \wock +1; not all orbits are elementarily definable; there is no arithmetic description of all orbits of \E; for all finite α≥9\alpha \geq 9, there is a properly Δα0\Delta^0_\alpha orbit (from the proof). A few small corrections made in this versionComment: To appear in the Bulletion of Symbolic Logi

    Addition of a gamma ray spectrometer to the alpha scattering experiment as designed for the Surveyor mission

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    Gamma ray spectroscopy and alpha scattering techniques for compositional analysis of lunar and planetary surface

    Silicon and magnesium in planetary nebulae

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    The IUE satellite spectra of some planetary nebulae show features due to silicon and magnesium: Si III wavelengths 1883, 1892; Si IV wavelengths 1394, 1403; Mg II wavelengths 2796, 2804 and Mg V wavelengths 2784, 2929. With the aid of modeling techniques, the corresponding elemental abundances are found. In addition to previous observations of NGC 7662 and IC 418, data were found for NGC 2440, Hu 1-2, IC 2003 and IC 2165. Silicon appears depleted by up to an order of magnitude relative to the sun. Large variations of magnesium abundance are found, which are likely to reflect differing degrees of depletion due to grain formation
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