3,369 research outputs found

    Geographical information retrieval with ontologies of place

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    Geographical context is required of many information retrieval tasks in which the target of the search may be documents, images or records which are referenced to geographical space only by means of place names. Often there may be an imprecise match between the query name and the names associated with candidate sources of information. There is a need therefore for geographical information retrieval facilities that can rank the relevance of candidate information with respect to geographical closeness of place as well as semantic closeness with respect to the information of interest. Here we present an ontology of place that combines limited coordinate data with semantic and qualitative spatial relationships between places. This parsimonious model of geographical place supports maintenance of knowledge of place names that relate to extensive regions of the Earth at multiple levels of granularity. The ontology has been implemented with a semantic modelling system linking non-spatial conceptual hierarchies with the place ontology. An hierarchical spatial distance measure is combined with Euclidean distance between place centroids to create a hybrid spatial distance measure. This is integrated with thematic distance, based on classification semantics, to create an integrated semantic closeness measure that can be used for a relevance ranking of retrieved objects

    Complementary reaction analyses and the isospin mixing of the 4- states in 16O

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    Data from the inelastic scattering of electrons, and of intermediate energy protons and pions leading to ``stretched'' configuration 4- states near 19 MeV excitation in 16O as well as from charge exchange (p,n) scattering to an isobaric analogue (4-) state in 16F have been analyzed to ascertain the degree of isospin mixing contained within those states and of the amount of d_{5/2}-p_{3/2}^{-1} particle-hole excitation strength they exhaust. The electron and proton scattering data have been analyzed using microscopic models of the structure and reactions, with details constrained by analyses of elastic scattering data.Comment: 25 pages, 12 figure

    Laboratory Focus on Improving the Culture of Biosafety: Statewide Risk Assessment of Clinical Laboratories That Process Specimens for Microbiologic Analysis

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    The Wisconsin State Laboratory of Hygiene challenged Wisconsin laboratories to examine their biosafety practices and improve their culture of biosafety. One hundred three clinical and public health laboratories completed a questionnaire-based, microbiology-focused biosafety risk assessment. Greater than 96% of the respondents performed activities related to specimen processing, direct microscopic examination, and rapid nonmolecular testing, while approximately 60% performed culture interpretation. Although they are important to the assessment of risk, data specific to patient occupation, symptoms, and travel history were often unavailable to the laboratory and, therefore, less contributory to a microbiology-focused biosafety risk assessment than information on the specimen source and test requisition. Over 88% of the respondents complied with more than three-quarters of the mitigation control measures listed in the survey. Facility assessment revealed that subsets of laboratories that claim biosafety level 1, 2, or 3 status did not possess all of the biosafety elements considered minimally standard for their respective classifications. Many laboratories reported being able to quickly correct the minor deficiencies identified. Task assessment identified deficiencies that trended higher within the general (not microbiology-specific) laboratory for core activities, such as packaging and shipping, direct microscopic examination, and culture modalities solely involving screens for organism growth. For traditional microbiology departments, opportunities for improvement in the cultivation and management of highly infectious agents, such as acid-fast bacilli and systemic fungi, were revealed. These results derived from a survey of a large cohort of small- and large-scale laboratories suggest the necessity for continued microbiology-based understanding of biosafety practices, vigilance toward biosafety, and enforcement of biosafety practices throughout the laboratory setting

    Gravity Spy: Integrating Advanced LIGO Detector Characterization, Machine Learning, and Citizen Science

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    (abridged for arXiv) With the first direct detection of gravitational waves, the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) has initiated a new field of astronomy by providing an alternate means of sensing the universe. The extreme sensitivity required to make such detections is achieved through exquisite isolation of all sensitive components of LIGO from non-gravitational-wave disturbances. Nonetheless, LIGO is still susceptible to a variety of instrumental and environmental sources of noise that contaminate the data. Of particular concern are noise features known as glitches, which are transient and non-Gaussian in their nature, and occur at a high enough rate so that accidental coincidence between the two LIGO detectors is non-negligible. In this paper we describe an innovative project that combines crowdsourcing with machine learning to aid in the challenging task of categorizing all of the glitches recorded by the LIGO detectors. Through the Zooniverse platform, we engage and recruit volunteers from the public to categorize images of glitches into pre-identified morphological classes and to discover new classes that appear as the detectors evolve. In addition, machine learning algorithms are used to categorize images after being trained on human-classified examples of the morphological classes. Leveraging the strengths of both classification methods, we create a combined method with the aim of improving the efficiency and accuracy of each individual classifier. The resulting classification and characterization should help LIGO scientists to identify causes of glitches and subsequently eliminate them from the data or the detector entirely, thereby improving the rate and accuracy of gravitational-wave observations. We demonstrate these methods using a small subset of data from LIGO's first observing run.Comment: 27 pages, 8 figures, 1 tabl

    Neutral Hydrogen Clouds near Early-Type Dwarf Galaxies of the Local Group

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    Parkes neutral hydrogen 21 cm line (HI) observations of the surroundings of 9 early-type Local Group dwarfs are presented. We detected numerous HI clouds in the general direction of those dwarfs and these clouds are often offset from the optical center of the galaxies. Although all the observed dwarfs, except Antlia, occupy phase-space regions where the High-Velocity Cloud (HVC) density is well above average, the measured offsets are smaller than one would expect from a fully random cloud distribution. Possible association is detected for 11 of the 16 investigated clouds, while, for two galaxies, Sextans and Leo I, no HI was detected. The galaxies where HI clouds were found not to coincide with the optical, yet have a significant probability of being associated are: Sculptor dSph, Tucanna, LGS3, Cetus, and Fornax. If the clouds are indeed associated, these galaxies have HI masses of MHI=2×105MM_{HI} = 2\times10^5 M_{\odot}, MHI=2×106MM_{HI} = 2\times10^6 M_{\odot}, MHI=7×105MM_{HI} = 7\times10^5 M_{\odot}, MHI=7×105MM_{HI} = 7\times10^5 M_{\odot}, and MHI=1×105MM_{HI} = 1\times10^5 M_{\odot}, respectively. However, neither ram pressure nor tidal stripping can easily explain the offsets. In some cases, large offsets are found where ram pressure should be the least effective.Comment: Accepted in AJ, June 200

    Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Are There Cosmic Microwave Background Anomalies?

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    (Abridged) A simple six-parameter LCDM model provides a successful fit to WMAP data, both when the data are analyzed alone and in combination with other cosmological data. Even so, it is appropriate to search for any hints of deviations from the now standard model of cosmology, which includes inflation, dark energy, dark matter, baryons, and neutrinos. The cosmological community has subjected the WMAP data to extensive and varied analyses. While there is widespread agreement as to the overall success of the six-parameter LCDM model, various "anomalies" have been reported relative to that model. In this paper we examine potential anomalies and present analyses and assessments of their significance. In most cases we find that claimed anomalies depend on posterior selection of some aspect or subset of the data. Compared with sky simulations based on the best fit model, one can select for low probability features of the WMAP data. Low probability features are expected, but it is not usually straightforward to determine whether any particular low probability feature is the result of the a posteriori selection or of non-standard cosmology. We examine in detail the properties of the power spectrum with respect to the LCDM model. We examine several potential or previously claimed anomalies in the sky maps and power spectra, including cold spots, low quadrupole power, quadropole-octupole alignment, hemispherical or dipole power asymmetry, and quadrupole power asymmetry. We conclude that there is no compelling evidence for deviations from the LCDM model, which is generally an acceptable statistical fit to WMAP and other cosmological data.Comment: 19 pages, 17 figures, also available with higher-res figures on http://lambda.gsfc.nasa.gov; accepted by ApJS; (v2) text as accepte

    Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results

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    We present cosmological parameter constraints based on the final nine-year WMAP data, in conjunction with additional cosmological data sets. The WMAP data alone, and in combination, continue to be remarkably well fit by a six-parameter LCDM model. When WMAP data are combined with measurements of the high-l CMB anisotropy, the BAO scale, and the Hubble constant, the densities, Omegabh2, Omegach2, and Omega_L, are each determined to a precision of ~1.5%. The amplitude of the primordial spectrum is measured to within 3%, and there is now evidence for a tilt in the primordial spectrum at the 5sigma level, confirming the first detection of tilt based on the five-year WMAP data. At the end of the WMAP mission, the nine-year data decrease the allowable volume of the six-dimensional LCDM parameter space by a factor of 68,000 relative to pre-WMAP measurements. We investigate a number of data combinations and show that their LCDM parameter fits are consistent. New limits on deviations from the six-parameter model are presented, for example: the fractional contribution of tensor modes is limited to r<0.13 (95% CL); the spatial curvature parameter is limited to -0.0027 (+0.0039/-0.0038); the summed mass of neutrinos is <0.44 eV (95% CL); and the number of relativistic species is found to be 3.84+/-0.40 when the full data are analyzed. The joint constraint on Neff and the primordial helium abundance agrees with the prediction of standard Big Bang nucleosynthesis. We compare recent PLANCK measurements of the Sunyaev-Zel'dovich effect with our seven-year measurements, and show their mutual agreement. Our analysis of the polarization pattern around temperature extrema is updated. This confirms a fundamental prediction of the standard cosmological model and provides a striking illustration of acoustic oscillations and adiabatic initial conditions in the early universe.Comment: 32 pages, 12 figures, v3: Version accepted to Astrophysical Journal Supplement Series. Includes improvements in response to referee and community; corrected 3 entries in Table 10, (w0 & wa model). See the Legacy Archive for Microwave Background Data Analysis (LAMBDA): http://lambda.gsfc.nasa.gov/product/map/current/ for further detai

    HI in Arp72 and similarities with M51-type systems

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    We present neutral hydrogen (H{\sc i}) observations with the Giant Metrewave Radio Telescope ({\it GMRT}) of the interacting galaxies NGC5996 and NGC5994, which make up the Arp72 system. Arp72 is an M51-type system and shows a complex distribution of H{\sc i} tails and a bridge due to tidal interactions. H{\sc i} column densities ranging from 0.81.8×1020-1.8\times10^{20} atoms cm2^{-2} in the eastern tidal tail to 1.72×1021-2\times10^{21} atoms cm2^{-2} in the bridge connecting the two galaxies, are seen to be associated with star-forming regions. We discuss the morphological and kinematic similarities of Arp72 with M51, the archetypal example of the M51-type systems, and Arp86, another M51-type system studied with the {\it GMRT}, and suggest that a multiple passage model of Salo & Laurikainen may be preferred over the classical single passage model of Toomre & Toomre, to reproduce the H{\sc i} features in Arp72 as well as in other M-51 systems depicting similar optical and H{\sc i} features.Comment: 8 pages, 6 figures, accepted for publication in MNRA
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