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Journal articles on the topic 'Opacity maps'
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1
Yuksel, Cem, and John Keyser. "Deep Opacity Maps." Computer Graphics Forum 27, no. 2 (2008): 675–80. http://dx.doi.org/10.1111/j.1467-8659.2008.01165.x.
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Faison, M. D., W. M. Goss та P. J. Diamond. "Mapping Small Scale Structure in Galactic H ɪ with the VLBA". International Astronomical Union Colloquium 164 (1998): 289–90. http://dx.doi.org/10.1017/s0252921100045607.
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AbstractWe present the first VLBA maps of Galactic H ɪ opacity towards the QSO 3C 138. The maps show significant opacity structure down to angular scales of 20 mas, which implies density structures in the cold neutral medium on physical scales of 10 AU or less
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C. Balachandran, Suchitra. "Beryllium in the Sun: Re-Measurement and Implications." Symposium - International Astronomical Union 198 (2000): 383–88. http://dx.doi.org/10.1017/s0074180900166951.
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The solar beryllium abundance is important because it provides a constraint on the depth to which mixing has occurred below the surface convective zone. Unlike helioseismology which only maps the present-day Sun, the solar beryllium abundance provides an integrated picture of mixing over the entire history of the Sun. In this review I outline the logic involving the ‘missing UV opacity’ that required that the solar beryllium abundance be re-determined. A brief summary of the empirical process of estimating the “missing UV opacity” is given along with a confirmation based on a recent re-calculation of the Fe I bound-free opacity. The addition of this opacity resulted in our finding that the solar beryllium abundance was meteoritic. The implications of this result in the context of mixing in solar-type stars is discussed.
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Bastien, Pierre, and Roger Hajjar. "Density Distribution in Disks around Protostellar Objects." Symposium - International Astronomical Union 202 (2004): 322–24. http://dx.doi.org/10.1017/s0074180900218135.
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A new method to find the density distribution in disks around protostellar objects, based on linear polarization maps, is presented. This method uses the displacement of the polarization null points as a function of wavelength. Variations in optical depth are converted into density variations with opacity tables for dust grains. The method has been applied with five linear polarization maps obtained at different wavelengths of the classical T Tauri star HL Tau. The slope of the density as a function of radius in the disk is compatible with the model of the standard protosolar nebula. The total mass of the disk is compatible with values determined by other methods. Other objects have been analyzed, with similar results, although with a smaller number of wavelength bands.
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Ott, Jürgen, Tony Wong, Jorge L. Pineda, et al. "The Molecular Ridge Close to 30 Doradus in the Large Magellanic Cloud." Publications of the Astronomical Society of Australia 25, no. 3 (2008): 129–37. http://dx.doi.org/10.1071/as07054.
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AbstractWith the ATNF Mopra telescope we are performing a survey in the 12CO(1–0) line to map the molecular gas in the Large Magellanic Cloud. For some regions we also obtained interferometric maps of the high density gas tracers HCO+ and HCN with the Australia Telescope Compact Array. Here we discuss the properties of the elongated molecular complex that stretches about 2 kpc southward from 30 Doradus. Our data suggest that the complex, which we refer to as the ‘molecular ridge’, is not a coherent feature but consists of many smaller clumps that share the same formation history. Likely triggers of molecular-cloud formation are shocks and shearing forces that are present in the surrounding south-eastern Hi overdensity region, a region influenced by strong ram pressure and tidal forces. The molecular ridge is at the western edge of the the overdensity region where a bifurcated velocity structure transitions into a single disk velocity component. We find that the 12CO(1–0) and Hi emission peaks in the molecular ridge are typically near each other but never coincide. A likely explanation is the conversion of warmer, low-opacity Hi to colder, high-opacity Hi from which H2 subsequently forms. On smaller scales we find that very dense molecular gas, as traced by interferometric HCO+ and HCN maps, is associated with star formation along shocked filaments and with rims of expanding shell-like structures, both created by feedback from massive stars.
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Ogaki, Shinji. "Generalized Light Portals." Proceedings of the ACM on Computer Graphics and Interactive Techniques 3, no. 2 (2020): 1–19. http://dx.doi.org/10.1145/3406176.
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Light portals are useful for accelerating the convergence of Monte Carlo path tracing when rendering interiors. However, they are generally limited to flat polygonal shapes. In this paper, we introduce a new concept that allows existing polygon meshes with arbitrary shaders in a scene to be used as generalized light portals. We also present an efficient sampling method that takes into account the pixel values of the environment map and ray guiding two-dimensional textures that are typically opacity or transparency maps. This novel sampling strategy can be combined with other sampling techniques by using multiple importance sampling.
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Brovelli, M. A., F. C. Fahl, M. Minghini, and M. E. Molinari. "LAND USER AND LAND COVER MAPS OF EUROPE: A WEBGIS PLATFORM." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B7 (June 22, 2016): 913–17. http://dx.doi.org/10.5194/isprsarchives-xli-b7-913-2016.
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This paper presents the methods and implementation processes of a WebGIS platform designed to publish the available land use and land cover maps of Europe at continental scale. The system is built completely on open source infrastructure and open standards. The proposed architecture is based on a server-client model having GeoServer as the map server, Leaflet as the client-side mapping library and the Bootstrap framework at the core of the front-end user interface. The web user interface is designed to have typical features of a desktop GIS (e.g. activate/deactivate layers and order layers by drag and drop actions) and to show specific information on the activated layers (e.g. legend and simplified metadata). Users have the possibility to change the base map from a given list of map providers (e.g. OpenStreetMap and Microsoft Bing) and to control the opacity of each layer to facilitate the comparison with both other land cover layers and the underlying base map. In addition, users can add to the platform any custom layer available through a Web Map Service (WMS) and activate the visualization of photos from popular photo sharing services. This last functionality is provided in order to have a visual assessment of the available land coverages based on other user-generated contents available on the Internet. It is supposed to be a first step towards a calibration/validation service that will be made available in the future.
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Brovelli, M. A., F. C. Fahl, M. Minghini, and M. E. Molinari. "LAND USER AND LAND COVER MAPS OF EUROPE: A WEBGIS PLATFORM." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B7 (June 22, 2016): 913–17. http://dx.doi.org/10.5194/isprs-archives-xli-b7-913-2016.
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This paper presents the methods and implementation processes of a WebGIS platform designed to publish the available land use and land cover maps of Europe at continental scale. The system is built completely on open source infrastructure and open standards. The proposed architecture is based on a server-client model having GeoServer as the map server, Leaflet as the client-side mapping library and the Bootstrap framework at the core of the front-end user interface. The web user interface is designed to have typical features of a desktop GIS (e.g. activate/deactivate layers and order layers by drag and drop actions) and to show specific information on the activated layers (e.g. legend and simplified metadata). Users have the possibility to change the base map from a given list of map providers (e.g. OpenStreetMap and Microsoft Bing) and to control the opacity of each layer to facilitate the comparison with both other land cover layers and the underlying base map. In addition, users can add to the platform any custom layer available through a Web Map Service (WMS) and activate the visualization of photos from popular photo sharing services. This last functionality is provided in order to have a visual assessment of the available land coverages based on other user-generated contents available on the Internet. It is supposed to be a first step towards a calibration/validation service that will be made available in the future.
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Ott, Jürgen, David S. Meier, Nico Krieger, and Matthew Rickert. "SWAG: Survey of Water and Ammonia in the Galactic Center." Proceedings of the International Astronomical Union 11, S322 (2016): 143–44. http://dx.doi.org/10.1017/s1743921316011789.
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AbstractSWAG (“Survey of Water and Ammonia in the Galactic Center”) is a multi-line interferometric survey toward the Center of the Milky Way conducted with the Australia Telescope Compact Array. The survey region spans the entire ~400 pc Central Molecular Zone and comprises ~42 spectral lines at pc spatial and sub-km/s spectral resolution. In addition, we deeply map continuum intensity, spectral index, and polarization at the frequencies where synchrotron, free-free, and thermal dust sources emit. The observed spectral lines include many transitions of ammonia, which we use to construct maps of molecular gas temperature, opacity and gas formation temperature (see poster by Nico Krieger et al., this volume). Water masers pinpoint the sites of active star formation and other lines are good tracers for density, radiation field, shocks, and ionization. This extremely rich survey forms a perfect basis to construct maps of the physical parameters of the gas in this extreme environment.
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Chiarelli, Antonio M., Kathy A. Low, Edward L. Maclin, et al. "The Optical Effective Attenuation Coefficient as an Informative Measure of Brain Health in Aging." Photonics 6, no. 3 (2019): 79. http://dx.doi.org/10.3390/photonics6030079.
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Aging is accompanied by widespread changes in brain tissue. Here, we hypothesized that head tissue opacity to near-infrared light provides information about the health status of the brain’s cortical mantle. In diffusive media such as the head, opacity is quantified through the Effective Attenuation Coefficient (EAC), which is proportional to the geometric mean of the absorption and reduced scattering coefficients. EAC is estimated by the slope of the relationship between source–detector distance and the logarithm of the amount of light reaching the detector (optical density). We obtained EAC maps across the head in 47 adults (age range 18–75 years), using a high-density dual-wavelength optical system. We correlated regional and global EAC measures with demographic, neuropsychological, structural and functional brain data. Results indicated that EAC values averaged across wavelengths were strongly associated with age-related changes in cortical thickness, as well as functional and neuropsychological measures. This is likely because the EAC largely depends on the thickness of the sub-arachnoid cerebrospinal fluid layer, which increases with cortical atrophy. In addition, differences in EAC values between wavelengths were correlated with tissue oxygenation and cardiorespiratory fitness, indicating that information about cortical health can be derived non-invasively by quantifying the EAC.
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Markieta, Michael, and Claus Rinner. "Using Distributed Map Overlay and Layer Opacity for Visual Multi-Criteria Analysis." GEOMATICA 68, no. 2 (2014): 95–105. http://dx.doi.org/10.5623/cig2014-202.
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Strategic decision-making is often based on multiple decision criteria and on the decision-makers’ preferences regarding relative criterion importance. We present version 2 of a map overlay and opacity tool (moot2), which supports the visual exploration of decision-making scenarios. The tool uses a basic function of geographic information systems (GIS): visual map overlay. In this approach, visual overlay serves as a representation of weighted linear combination in multi-criteria decision analysis (MCDA). Using the tool, we model a global human influence index for the extent of the province of Ontario, Canada. The index is a weighted overlay of six indicators that represent human influence on the land. The semi-transparent overlay of the six indicator layers occurs online in a web browser, making it accessible to distant collaborators in low-technology settings. The software architecture of moot2 includes the OpenLayers JavaScript library to display thematic Web Map Service (WMS) layers, such as the human influence indicators, on top of popular base map services, such as OpenStreetMap or Google Maps. The tool also uses jQuery, a JavaScript library that enables interactions between the user and the map environment. Layer opacity is manipulated by the jQuery Slider, permitting the user to generate on-the-fly weighting schemes for the combination of the human influence indicators. By removing the analytical engine (i.e., GIS), decision-makers can perform rapid MCDA without recalculating composite evaluation scores. The case study demonstrates how visual-spatial MCDA supports the refinement of decision-making parameters such as criterion weights.
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Juvela, Mika, Jinhua He, Katherine Pattle, et al. "Herschel and SCUBA-2 observations of dust emission in a sample of Planck cold clumps." Astronomy & Astrophysics 612 (April 2018): A71. http://dx.doi.org/10.1051/0004-6361/201731921.
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Context. Analysis of all-sky Planck submillimetre observations and the IRAS 100 μm data has led to the detection of a population of Galactic cold clumps. The clumps can be used to study star formation and dust properties in a wide range of Galactic environments. Aims. Our aim is to measure dust spectral energy distribution (SED) variations as a function of the spatial scale and the wavelength. Methods. We examined the SEDs at large scales using IRAS, Planck, and Herschel data. At smaller scales, we compared JCMT/SCUBA-2 850 μm maps with Herschel data that were filtered using the SCUBA-2 pipeline. Clumps were extracted using the Fellwalker method, and their spectra were modelled as modified blackbody functions. Results. According to IRAS and Planck data, most fields have dust colour temperatures TC ~ 14–18 K and opacity spectral index values of β = 1.5–1.9. The clumps and cores identified in SCUBA-2 maps have T ~ 13 K and similar β values. There are some indications of the dust emission spectrum becoming flatter at wavelengths longer than 500 μm. In fits involving Planck data, the significance is limited by the uncertainty of the corrections for CO line contamination. The fits to the SPIRE data give a median β value that is slightly above 1.8. In the joint SPIRE and SCUBA-2 850 μm fits, the value decreases to β ~ 1.6. Most of the observed T-β anticorrelation can be explained by noise. Conclusions. The typical submillimetre opacity spectral index β of cold clumps is found to be ~1.7. This is above the values of diffuse clouds, but lower than in some previous studies of dense clumps. There is only tentative evidence of a T-β anticorrelation and β decreasing at millimetre wavelengths.
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Miller, Joel S. A., James S. Bolton та Nina A. Hatch. "Searching for the shadows of giants – II. The effect of local ionization on the Ly α absorption signatures of protoclusters at redshift z ∼ 2.4". Monthly Notices of the Royal Astronomical Society 506, № 4 (2021): 6001–13. http://dx.doi.org/10.1093/mnras/stab2083.
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ABSTRACT Local variations in the intergalactic medium (IGM) neutral hydrogen fraction will affect the Ly α absorption signature of protoclusters identified in tomographic surveys. Using the IllustrisTNG simulations, we investigate how the AGN proximity effect and hot, collisionally ionized gas arising from gravitational infall and black hole feedback changes the Ly α absorption associated with $M_{z=0}\simeq 10^{14}\, {\rm M}_\odot$ protoclusters at z ≃ 2.4. We find that protocluster galaxy overdensities exhibit a weak anticorrelation with Ly α transmission in IGM transmission maps, but local H$\, \rm \scriptstyle I$ ionization enhancements due to hot $T\gt 10^{6}\rm \, K$ gas or nearby AGN can disrupt this relationship within individual protoclusters. On average, however, we find that strong reductions in the IGM neutral fraction are limited to within $\lesssim 5h^{-1}\, \textrm {cMpc}$ of the dark matter haloes. Local ionization enhancements will therefore have a minimal impact on the completeness of protocluster identification in tomographic surveys if smoothing Ly α transmission maps over scales of $\sim 4 h^{-1}\, \textrm {cMpc}$, as is typically done in observations. However, if calibrating the relationship between the matter density and Ly α transmission in tomographic maps using simple analytical models for the Ly α forest opacity, the presence of hot gas around haloes can still result in systematically lower estimates of Mz = 0 for the most massive protoclusters.
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Krieger, Nico, Jürgen Ott, Fabian Walter, J. M. Diederik Kruijssen, and Henrik Beuther. "Temperature Evolution of Molecular Clouds in the Central Molecular Zone." Proceedings of the International Astronomical Union 11, S322 (2016): 160–61. http://dx.doi.org/10.1017/s1743921316011960.
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AbstractWe infer the absolute time dependence of kinematic gas temperature along a proposed orbit of molecular clouds in the Central Molecular Zone (CMZ) of the Galactic Center (GC). Ammonia gas temperature maps are one of the results of the “Survey of Water and Ammonia in the Galactic Center” (SWAG, PI: J. Ott); the dynamical model of molecular clouds in the CMZ was taken from Kruijssen et al. (2015). We find that gas temperatures increase as a function of time in both regimes before and after the cloud passes pericenter on its orbit in the GC potential. This is consistent with the recent proposal that pericenter passage triggers gravitational collapse. Other investigated quantities (line width, column density, opacity) show no strong sign of time dependence but are likely dominated by cloud-to-cloud variations.
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Cooley, Heidi Rae. "Productive Mis-mappings: Critical Disorientations on the University of South Carolina’s Historic Horseshoe." Television & New Media 18, no. 4 (2016): 361–74. http://dx.doi.org/10.1177/1527476416667819.
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Located at the heart of the University of South Carolina campus is the historic Horseshoe—originally the South Carolina College campus (est. 1801)—a site whose construction during the antebellum years relied on enslaved labor. Ghosts of the Horseshoe is a cross-College, collaborative “critical interactive” for iPad that features the Horseshoe campus and endeavors to make visible this unacknowledged history. The application uses as its dedicated navigational interface a historic 1884 Sanborn Fire Insurance map of the site; participants can also activate a Google Map overlay of the site and determine its degree of opacity with respect to the archival map image. Importantly, however, the two maps do not actually “map” onto each other. This serves as a first mis-mapping of several mis-mappings. This article considers how such mis-mappings, involving geo-locative contingencies, representational disjunctions, and potential dis-locations, mediate site-specific explorations and, as such, make possible alternative historiographic understandings of place.
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Thiel, V., A. Belloche, K. M. Menten, et al. "Small-scale physical and chemical structure of diffuse and translucent molecular clouds along the line of sight to Sgr B2." Astronomy & Astrophysics 623 (March 2019): A68. http://dx.doi.org/10.1051/0004-6361/201834467.
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Context. The diffuse and translucent molecular clouds traced in absorption along the line of sight to strong background sources have so far been investigated mainly in the spectral domain because of limited angular resolution or small sizes of the background sources. Aims. We aim to resolve and investigate the spatial structure of molecular clouds traced by several molecules detected in absorption along the line of sight to Sgr B2(N). Methods. We have used spectral line data from the EMoCA survey performed with the Atacama Large Millimeter/submillimeter Array (ALMA), taking advantage of its high sensitivity and angular resolution. The velocity structure across the field of view is investigated by automatically fitting synthetic spectra to the detected absorption features, which allows us to decompose them into individual clouds located in the Galactic centre (GC) region and in spiral arms along the line of sight. We compute opacity maps for all detected molecules. We investigated the spatial and kinematical structure of the individual clouds with statistical methods and perform a principal component analysis to search for correlations between the detected molecules. To investigate the nature of the molecular clouds along the line of sight to Sgr B2, we also used archival Mopra data. Results. We identify, on the basis of c-C3H2, 15 main velocity components along the line of sight to Sgr B2(N) and several components associated with the envelope of Sgr B2 itself. The c-C3H2 column densities reveal two categories of clouds. Clouds in Category I (3 kpc arm, 4 kpc arm, and some GC clouds) have smaller c-C3H2 column densities, smaller linewidths, and smaller widths of their column density PDFs than clouds in Category II (Scutum arm, Sgr arm, and other GC clouds). We derive opacity maps for the following molecules: c-C3H2, H13CO+, 13CO, HNC and its isotopologue HN13C, HC15N, CS and its isotopologues C34S and 13CS, SiO, SO, and CH3OH. These maps reveal that most molecules trace relatively homogeneous structures that are more extended than the field of view defined by the background continuum emission (about 15′′, that is 0.08–0.6 pc depending on the distance). SO and SiO show more complex structures with smaller clumps of size ~5–8′′. Our analysis suggests that the driving of the turbulence is mainly solenoidal in the investigated clouds. Conclusions. On the basis of HCO+, we conclude that most line-of-sight clouds towards Sgr B2 are translucent, including all clouds where complex organic molecules were recently detected. We also conclude that CCH and CH are good probes of H2 in both diffuse and translucent clouds, while HCO+ and c-C3H2 in translucent clouds depart from the correlations with H2 found in diffuse clouds.
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Riks, Inna A., Sergey Yu Astakhov, Elena М. Ivankova, et al. "Cases of opacity of intraocular lenses in artificial eyes: analysis of the results of microstructural studies." Ophthalmology journal 13, no. 3 (2021): 21–28. http://dx.doi.org/10.17816/ov41836.
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Relevance. Currently, all over the world, during cataract surgeries, a huge number of intraocular lenses (IOLs) made of different materials are implanted. Alongside with the development of modern IOL materials and designs, publications about their opacities appear. The nature and the localization of IOL opacities mainly depend on the properties of the material out of which the lens is made. Polymethyl methacrylate (PMMA) currently rarely used to manufacture IOLs, tends to cloud in the optical center due to structural breakdown, forming snowflake-like cracks. Opacities of acrylic IOLs depend on the degree of hydrophilic properties of the material. The deposition of crystalline deposits in the optical zone of hydrophilic acrylic lenses leads to a significant decrease in visual acuity and requires IOL explantation. There is a definite dependence of the occurrence of opacities in hydrophilic acryl on the patients concomitant diseases. In hydrophobic acrylic IOLs, vacuoles form, and glistenings occurs. Herewith, visual functions, as a rule, do not suffer.
 Purpose: to find out what structural changes in the IOL led to the need to remove them from pseudophakic eyes due to a decrease in visual acuity.
 Materials and methods. Four clouded IOLs made from different materials were examined. The lenses were studied using a SUPRA 55VP scanning electron microscope (Carl Zeiss, Germany) using a secondary electron detector. Element distribution maps on the surface and inside the lenses were collected using an X-max 80 mm2 energy dispersive X-ray analysis detector (Oxford Instruments, UK).
 Results. A hydrophilic lens with hydrophobic coating became cloudy 5 years after implantation. Hydroxyapatite crystals were found on all parts of the IOL along its surface. In a hydrophobic acrylic IOL, microvacuoles and cavities in the optical center were found using scanning electron microscopy. Two PMMA IOLs underwent self-destruction within 8 years after implantation. Chemical analysis of PMMA lenses did not reveal any inorganic compounds.
 Conclusion. One of the complications of IOL implantation is an impairment of their transparency. Factors associated with IOL material and manufacturing, as well as the patients comorbidities, can lead to lens opacification at various terms after surgery.
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Darvann, Tron A. "Measurements of Horizontal Flows in 1.6 μm Granulation". Symposium - International Astronomical Union 154 (1994): 259–64. http://dx.doi.org/10.1017/s0074180900124507.
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We report on a first analysis of the horizontal motions in a 45 minute (32 × 22 arcsec2 field of view) granulation time series (movie presented at the present IAU Symposium) obtained at 1.6 μm with the Vacuum Tower Telescope (VTT) of the National Solar Observatory at Sacramento Peak (NSO/SP). High signal/noise flow maps are obtained by use of the local cross correlation technique (November 1986) which incorporates efficient attenuation of seeing and 5-min oscillations. The flow pattern, showing a (≈ 30 arcsec diameter) supergranule with (≈ 8-15 arcsec) mesogranules superposed, is long lived compared to the 45 min of observations. The computed flows (velocity, divergence, vorticity) resemble the ones obtained at visible wavelengths (e.g., by Brandt et al. 1991, November 1989, November and Simon 1988, Simon et al. 1988). The high quality of the the flow maps (due to a large number of selected images (1500), and (supposedly) smaller 5-min oscillations and better seeing conditions at 1.6 μm) allows us to study time evolution (resolution ≈ 15 min) of the details of the flow (spatial resolution ≈ 3 arcsec). An interesting new finding is the short lifetime (< 45 min) of vorticity as opposed to the long lived (≫ 45 min) divergence of the flow. Our study demonstrates the possibility of using the 1.6 μm window to the opacity minimum region to study the horizontal flows at these deep layers of the photosphere.
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Fargion, Daniele. "RADIOACTIVE UHECR ASTRONOMY: CORRELATING GAMMA ANISOTROPY AND NEUTRINO PEV EVENTS." Acta Polytechnica 53, A (2013): 718–23. http://dx.doi.org/10.14311/ap.2013.53.0718.
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UHECR (Ultra High Energy Cosmic Rays) were expected to be protons, to fly straight and to suffer of a GZK (opacity on CMB radiation) cut off. AUGER did suggest on 2007 that such early UHECR anisotropy was compatible with the foreseen Super-Galactic plane while both HIRES and AUGER confirmed such apparent GZK cut-off in the spectra. However the same AUGER composition since 2007 was favoring nuclei (and not nucleon). The recent absence of narrow angle clustering in UHECR maps, as it should be expected by protons, the missing of events along nearest Cluster Virgo, the wide spread (16°) angle of UHECR along CenA are in disagreement with first proton–UHECR AUGER understanding. We claimed since 2008 a light nuclei role for CenA crowded area. On the other side the ICECUBE absence of TeVs neutrino clustering or anisotropy, its spectra steepening is favoring mostly a ruling atmospheric neutrino noise up to tens TeV. However recent two PeV neutrino event cannot easily coexist or being extrapolate with such atmospheric ruling scenario, nor with GZK (either nucleon or nuclei) secondaries expected spectra. Finally tens TeV gamma anisotropy in ARGO–MILAGRO–ICECUBE maps may hardly be associated with known hadronic sources. We<br />imagine such anisotropy ruled by diffused gamma secondaries, being shine along UHECR bending and flight: radioactive light and heavy UHECR nuclei, while decaying in flight, may paint in the sky (by gamma, electrons and neutrinos) their trajectories and bending, connecting UHECR spread events with TeV anisotropy, as well offering a very realistic source of first, otherwise puzzling, observed PeV neutrinos.
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Finkbeiner, D. P., Marc Davis, and David Schlegel. "Detection of a Far IR Excess with DIRBE at 60 and 100 Microns." Symposium - International Astronomical Union 204 (2001): 121. http://dx.doi.org/10.1017/s0074180900225953.
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From analysis of the DIRBE weekly averaged sky maps, we have detected substantial flux in the 60 μm and 100 μm channels in excess of expected zodiacal and Galactic emission (Finkbeiner, D.P., et al. 2000, ApJ, to be published, astro-ph/0004175). Two methods are used to separate zodiacal light from more distant emission. Both methods give consistent results at 60 μm and 100 μm. The observed signal is consistent with an isotropic background of vIv = 28.1 ± 1.8 ± 7 (syst) nWm−2sr−1 at 60 μm and 24.6 ± 2.5 ± 8 (syst) nW m−2 sr−1 at 100 μm.The IR excess detected at 140 and 240 μm by these methods agrees with previous measurements, which are thought to be the cosmic infrared background (CIB). The detections at 60 and 100 μm are new. While this new excess is not necessarily the CIB, we have ruled out all known sources of emission in the solar system and Galaxy. We therefore tentatively interpret this signal as the CIB and consider the implications of such energy production from the viewpoint of star formation efficiency and black hole accretion efficiency. However, the IR excess exceeds limits on the CIB derived from the inferred opacity of the intergalactic medium to observed TeV photons, thus casting doubt on this interpretation. There is currently no satisfactory explanation for the 60 – 100 μm excess.
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Yusef-Zadeh, F., Mark Morris та Ron Ekers. "Multi-Array λ2 and 6cm Radio Continuum Observations of Sgr A West". Symposium - International Astronomical Union 136 (1989): 443–51. http://dx.doi.org/10.1017/s0074180900186875.
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Sub-arcsecond (down to 0.1″ × 0.2″) radio continuum observations using the VLA2 in a number of configurations have been carried out in order to investigate the fine-scale morphological details of the ionized gas and the distribution of spectral index along the triskelian-shaped figure of Sgr A West. In addition to finding a number of isolated patches of thermally-emitting gas and an absorbing feature at λ6cm within three arcminutes of the Galactic center, we have observed:1) radio continuum emission from IRS-7, implying that the stellar wind from this supergiant is externally ionized. An improved position for this object was obtained.2) the circular mini-cavity located along the east-west bar of Sgr A West. This feature has a diameter of 2-arcseconds and may have been created by a spherical wind, the source of which is yet to be identified; the seemingly most plausible candidate, IRS-16, is offset by 3″ from the center of the cavity.Spectral index maps having a resolution of 0.7″ × 0.3″ were made from scaled array observations at λ2cm and 6cm. They show that the eastern arm has a spectral index near −0.1, while the northern arm and the bar have positive spectral indices, indicating perhaps a partial opacity effect. The spectral index of IRS-7 is +0.6, consistent with that expected from a completely ionized stellar wind.
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Denham, Monica, Sigfrido Waidelich, and Karina Laneri. "Fire propagation visualization in real time." Journal of Computer Science and Technology 18, no. 03 (2018): e27. http://dx.doi.org/10.24215/16666038.18.e27.
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Our motivation comes from the need of a tailored computational tool for simulation and prediction of forest fire propagation, to be used by firefighters in Patagonia, Argentina. Based on previous works on Graphic Processing Units (GPU) for fitting and simulating fires in our region, we developed a visualization interface for real time computing, simulation and prediction of fire propagation. We have the possibility of changing the ensemble of raster maps layers to change the region in which fire will propagate.The visualization platform runs on GPUs and the user can rotate and zoom the landscape to select the optimal view of fire propagation. Opacity of different layers can be regulated by the user, allowing to see fire propagation at the same time that underlying vegetation, wind direction and intensity. The ignition point can also be selected by the user, and firebreaks can be plotted while simulation is going on.After the performance of a high number of stochastic simulations in parallel in GPUs, the application shows a map of the final fire surface colored according to the probability that a given cell burns. In this way the user can visually identify the most critical direction for fire propagation, a useful information to stop fire optimizing resources, which is specially important when they are scarce like is the case of our Patagonia region.
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Griselda Lopez, Daniela. "Schutzian social cartography." SOCIOLOGIA E RICERCA SOCIALE, no. 124 (May 2021): 69–90. http://dx.doi.org/10.3280/sr2021-124005.
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The aim of this paper is to explore an uncharted aspect of Schutzian description of the structure of the stock of knowledge. The linkage between the stock of knowledge and the life-world isexamined through the cartographic metaphor of the map. Starting from an analysis of different manuscripts, it is shown that the cartographic metaphor is the heuristic resource used by Alfred Schutz to depict the complex relationships between knowledge and life-world. It is argued that the allegorical reference to the use of maps expresses the conversion of our perception of the life-world into contour lines or hatchings, which corresponds to the phenomenological insight that objects are given in perception through manifesting sides or adumbrations. Moreover, it is stated that the metaphor of the relevance-isohypses helps Schutz to describe not only the structurization of our stock of knowledge into theme and horizon and the levels of familiarity and typicality we perceive in the objects of the world, but also the incomplete character of our knowledge, i.e., the shadows and hatchings sketched in it as a consequence of the opacity of the life-world. It is maintained that far from belonging solely to geography, the metaphor of the unknown world as a «terra incognita» suggests an inquiry into the process of production of knowledge. The cartographic blanks do not preclude the impossibility of knowledge, but, on the contrary, they constitute its original source.
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Helling, Ch, N. Iro, L. Corrales, et al. "Understanding the atmospheric properties and chemical composition of the ultra-hot Jupiter HAT-P-7b." Astronomy & Astrophysics 631 (October 25, 2019): A79. http://dx.doi.org/10.1051/0004-6361/201935771.
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Context. Of the presently known ≈3900 exoplanets, sparse spectral observations are available for ≈100. Ultra-hot Jupiters have recently attracted interest from observers and theoreticians alike, as they provide observationally accessible test cases. Confronting detailed theoretical models with observations is of preeminent importance in preparation for upcoming space-based telescopes. Aims. We aim to study cloud formation on the ultra-hot Jupiter HAT-P-7b, the resulting composition of the local gas phase, and how their global changes affect wavelength-dependent observations utilised to derive fundamental properties of the planet. Methods. We apply a hierarchical modelling approach as a virtual laboratory to study cloud formation and gas-phase chemistry. We utilise 97 vertical 1D profiles of a 3D GCM for HAT-P-7b to evaluate our kinetic cloud formation model consistently with the local equilibrium gas-phase composition. We use maps and slice views to provide a global understanding of the cloud and gas chemistry. Results. The day/night temperature difference on HAT-P-7b (ΔT ≈ 2500 K) causes clouds to form on the nightside (dominated by H2/He) while the dayside (dominated by H/He) retains cloud-free equatorial regions. The cloud particles vary in composition and size throughout the vertical extension of the cloud, but also globally. TiO2[s]/Al2O3[s]/CaTiO3[s]-particles of cm-sized radii occur in the higher dayside-latitudes, resulting in a dayside dominated by gas-phase opacity. The opacity on the nightside, however, is dominated by 0.01…0.1μm particles made of a material mix dominated by silicates. The gas pressure at which the atmosphere becomes optically thick is ~10−4 bar in cloudy regions, and ~0.1 bar in cloud-free regions. Conclusions. HAT-P-7b features strong morning/evening terminator asymmetries, providing an example of patchy clouds and azimuthally-inhomogeneous chemistry. Variable terminator properties may be accessible by ingress/egress transmission photometry (e.g., CHEOPS and PLATO) or spectroscopy. The large temperature differences of ≈2500 K result in an increasing geometrical extension from the night- to the dayside. The H2O abundance at the terminator changes by <1 dex with altitude and ≲0.3 dex (a factor of 2) across the terminator for a given pressure, indicating that H2O abundances derived from transmission spectra can be representative of the well-mixed metallicity at P ≳ 10 bar. We suggest the atmospheric C/O as an important tool to trace the presence and location of clouds in exoplanet atmospheres. The atmospheric C/O can be sub- and supersolar due to cloud formation. Phase curve variability of HAT-P-7b is unlikely to be caused by dayside clouds.
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Favor, Jack, and Walter Pretsch. "Genetic localization and phenotypic expression of X-linked cataract (Xcat) in Mus musculus." Genetics Research 56, no. 2-3 (1990): 157–62. http://dx.doi.org/10.1017/s0016672300035242.
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SummaryLinkage data relative to the markers tabby and glucose-6-phosphate dehydrogenase are presented to locate X-linked cataract (Xcat) in the distal portion of the mouse X-chromosome between jimpy and hypophosphatemia. The human X-linked cataract-dental syndrome, Nance–Horan Syndrome, also maps closely to human hypophosphatemia and would suggest homology between mouse Xcat and human Nance-Horan Syndrome genes. In hemizygous males and homozygous females penetrance is complete with only slight variation in the degree of expression. Phenotypic expression in Xcat heterozygous females ranges from totally clear to totally opaque lenses. The phenotypic expression between the two lenses of a heterozygous individual could also vary between totally clear and totally opaque lenses. However, a correlation in the degree of expression between the eyes of an individual was observed. A variegated pattern of lens opacity was evident in female heterozygotes. Based on these observations, the site of gene action for the Xcat locus is suggested to be endogenous to the lens cells and the precursor cell population of the lens is concluded to be small. The identification of an X-linked cataract locus is an important contribution to the estimate of the number of mutable loci resulting in cataract, an estimate required so that dominant cataract mutagenesis results may be expressed on a per locus basis. The Xcat mutation may be a useful marker for a distal region of the mouse X-chromosome which is relatively sparsely marked and the X-linked cataract mutation may be employed in gene expression and lens development studies.
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Howard, A. D. P., A. P. Whitworth, M. J. Griffin, K. A. Marsh, and M. W. L. Smith. "A PPMAP analysis of the filamentary structures in Ophiuchus L1688 and L1689." Monthly Notices of the Royal Astronomical Society 504, no. 4 (2021): 6157–78. http://dx.doi.org/10.1093/mnras/stab1166.
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ABSTRACT We use the Point Process MAPping (PPMAP) algorithm to reanalyse the Herschel and SCUBA-2 observations of the L1688 and L1689 subregions of the Ophiuchus molecular cloud. PPMAP delivers maps with high resolution (here 14 arcsec, corresponding to ${\sim}0.01\, {\rm pc}$ at ${\sim}140\, {\rm pc}$), by using the observations at their native resolutions. PPMAP also delivers more accurate dust optical depths, by distinguishing dust of different types and at different temperatures. The filaments and pre-stellar cores almost all lie in regions with $N_{\rm H_2}\gtrsim 7\times 10^{21}\, {\rm cm}^{-2}$ (corresponding to AV ≳ 7). The dust temperature, T, tends to be correlated with the dust opacity index, β, with low T and low β concentrated in the interiors of filaments. The one exception to this tendency is a section of filament in L1688 that falls – in projection – between the two B stars: S1 and HD147889; here T and β are relatively high, and there is compelling evidence that feedback from these two stars has heated and compressed the filament. Filament fwhms are typically in the range $0.10$ to $0.15\, {\rm pc}$. Most filaments have line-densities in the range $25$ to $65\, {\rm M_{\odot }\, pc^{-1}}$. If their only support is thermal gas pressure, and the gas is at the canonical temperature of $10\, {\rm K}$, the filaments are highly supercritical. However, there is some evidence from ammonia observations that the gas is significantly warmer than this, and we cannot rule out the possibility of additional support from turbulence and/or magnetic fields. On the basis of their spatial distribution, we argue that most of the starless cores are likely to disperse (rather than evolving to become pre-stellar).
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Alves, F. O., J. M. Girart, M. Padovani, et al. "Magnetic field in a young circumbinary disk." Astronomy & Astrophysics 616 (August 2018): A56. http://dx.doi.org/10.1051/0004-6361/201832935.
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Context. Polarized continuum emission at millimeter-to-submillimeter wavelengths is usually attributed to thermal emission from dust grains aligned through radiative torques with the magnetic field. However, recent theoretical work has shown that under specific conditions polarization may arise from self-scattering of thermal emission and by radiation fields from a nearby stellar object. Aims. We use multi-frequency polarization observations of a circumbinary disk to investigate how the polarization properties change at distinct frequency bands. Our goal is to discern the main mechanism responsible for the polarization through comparison between our observations and model predictions for each of the proposed mechanisms. Methods. We used the Atacama Large Millimeter/submillimeter Array to perform full polarization observations at 97.5 GHz (Band 3), 233 GHz (Band 6) and 343.5 GHz (Band 7). The ALMA data have a mean spatial resolution of 28 AU. The target is the Class I object BHB07-11, which is the youngest object in the Barnard 59 protocluster. Complementary Karl G. Jansky Very Large Array observations at 34.5 GHz were also performed and revealed a binary system at centimetric continuum emission within the disk. Results. We detect an extended and structured polarization pattern that is remarkably consistent between the three bands. The distribution of polarized intensity resembles a horseshoe shape with polarization angles following this morphology. From the spectral index between Bands 3 and 7, we derived a dust opacity index β ~ 1 consistent with maximum grain sizes larger than expected to produce self-scattering polarization in each band. The polarization morphology and the polarization levels do not match predictions from self-scattering. On the other hand, marginal correspondence is seen between our maps and predictions from a radiation field model assuming the brightest binary component as main radiation source. Previous molecular line data from BHB07-11 indicates disk rotation. We used the DustPol module of the ARTIST radiative transfer tool to produce synthetic polarization maps from a rotating magnetized disk model assuming combined poloidal and toroidal magnetic field components. The magnetic field vectors (i.e., the polarization vectors rotated by 90°) are better represented by a model with poloidal magnetic field strength about three times the toroidal one. Conclusions. The similarity of our polarization patterns among the three bands provides a strong evidence against self-scattering and radiation fields. On the other hand, our data are reasonably well reproduced by a model of disk with toroidal magnetic field components slightly smaller than poloidal ones. The residual is likely to be due to the internal twisting of the magnetic field due to the binary system dynamics, which is not considered in our model.
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Md Ali, Mohd Adli, Mohd Radhwan Abidin, Nik Arsyad Nik Muhamad Affendi, et al. "CLASSIFICATION OF CHEST RADIOGRAPHS USING NOVEL ANOMALOUS SALIENCY MAP AND DEEP CONVOLUTIONAL NEURAL NETWORK." IIUM Engineering Journal 22, no. 2 (2021): 234–48. http://dx.doi.org/10.31436/iiumej.v22i2.1752.
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The rapid advancement in pattern recognition via the deep learning method has made it possible to develop an autonomous medical image classification system. This system has proven robust and accurate in classifying most pathological features found in a medical image, such as airspace opacity, mass, and broken bone. Conventionally, this system takes routine medical images with minimum pre-processing as the model's input; in this research, we investigate if saliency maps can be an alternative model input. Recent research has shown that saliency maps' application increases deep learning model performance in image classification, object localization, and segmentation. However, conventional bottom-up saliency map algorithms regularly failed to localize salient or pathological anomalies in medical images. This failure is because most medical images are homogenous, lacking color, and contrast variant. Therefore, we also introduce the Xenafas algorithm in this paper. The algorithm creates a new kind of anomalous saliency map called the Intensity Probability Mapping and Weighted Intensity Probability Mapping. We tested the proposed saliency maps on five deep learning models based on common convolutional neural network architecture. The result of this experiment showed that using the proposed saliency map over regular radiograph chest images increases the sensitivity of most models in identifying images with air space opacities. Using the Grad-CAM algorithm, we showed how the proposed saliency map shifted the model attention to the relevant region in chest radiograph images. While in the qualitative study, it was found that the proposed saliency map regularly highlights anomalous features, including foreign objects and cardiomegaly. However, it is inconsistent in highlighting masses and nodules. ABSTRAK: Perkembangan pesat sistem pengecaman corak menggunakan kaedah pembelajaran mendalam membolehkan penghasilan sistem klasifikasi gambar perubatan secara automatik. Sistem ini berupaya menilai secara tepat jika terdapat tanda-tanda patologi di dalam gambar perubatan seperti kelegapan ruang udara, jisim dan tulang patah. Kebiasaannya, sistem ini akan mengambil gambar perubatan dengan pra-pemprosesan minimum sebagai input. Kajian ini adalah tentang potensi peta salien dapat dijadikan sebagai model input alternatif. Ini kerana kajian terkini telah menunjukkan penggunaan peta salien dapat meningkatkan prestasi model pembelajaran mendalam dalam pengklasifikasian gambar, pengesanan objek, dan segmentasi gambar. Walau bagaimanapun, sistem konvensional algoritma peta salien jenis bawah-ke-atas kebiasaannya gagal mengesan salien atau anomali patologi dalam gambar-gambar perubatan. Kegagalan ini disebabkan oleh sifat gambar perubatan yang homogen, kurang variasi warna dan kontras. Oleh itu, kajian ini memperkenalkan algoritma Xenafas yang menghasilkan dua jenis pemetaan saliensi anomali iaitu Pemetaan Kebarangkalian Keamatan dan Pemetaan Kebarangkalian Keamatan Pemberat. Kajian dibuat pada peta salien yang dicadangkan iaitu pada lima model pembelajaran mendalam berdasarkan seni bina rangkaian neural konvolusi yang sama. Dapatan kajian menunjukkan dengan menggunakan peta salien atas gambar-gambar radiografi dada tetap membantu kesensitifan kebanyakan model dalam mengidentifikasi gambar-gambar dengan kelegapan ruang udara. Dengan menggunakan algoritma Grad-CAM, peta salien yang dicadangkan ini mampu mengalih fokus model kepada kawasan yang relevan kepada gambar radiografi dada. Sementara itu, kajian kualitatif ini juga menunjukkan algoritma yang dicadangkan mampu memberi ciri anomali, termasuk objek asing dan kardiomegali. Walau bagaimanapun, ianya tidak konsisten dalam menjelaskan berat dan nodul.
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Molaverdikhani, K., Ch Helling, B. W. P. Lew, et al. "Understanding the atmospheric properties and chemical composition of the ultra-hot Jupiter HAT-P-7b." Astronomy & Astrophysics 635 (March 2020): A31. http://dx.doi.org/10.1051/0004-6361/201937044.
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Aims. The atmospheres of ultra-hot Jupiters (UHJs) are commonly considered to be at thermochemical equilibrium. We aim to provide disequilibrium chemistry maps for a global understanding of the chemistry in the atmosphere of HAT-P-7b and assess the importance of disequilibrium chemistry on UHJs. Methods. We applied a hierarchical modeling approach using 97 1D atmospheric profiles from a 3D general circulation model of HAT-P-7b. For each atmospheric 1D profile, we evaluated our kinetic cloud formation model consistently with the local gas-phase composition in chemical equilibrium. This served as input to study the quenching of dominating CHNO-binding molecules. We evaluated quenching results from a zeroth-order approximation in comparison to a kinetic gas-phase approach. Results. We find that the zeroth-order approach of estimating quenching points agrees well with the full gas-kinetic modeling results. However, it underestimates the quenching levels by about one order of magnitude at high temperatures. Chemical disequilibrium has the greatest effect on the nightside and morning abundance of species such as H, H2O, CH4, CO2, HCN, and all CnHm molecules; heavier CnHm molecules are more affected by disequilibrium processes. The CO abundance, however, is affected only marginally. While dayside abundances also notably change, those around the evening terminator of HAT-P-7b are the least affected by disequilibrium processes. The latter finding may partially explain the consistency of observed transmission spectra of UHJs with atmospheres in thermochemical equilibrium. Photochemistry only negligibly affects molecular abundances and quenching levels. Conclusions. In general, the quenching points of the atmosphere of HAT-P-7b are at much lower pressures than in the cooler hot-jupiters. We propose several avenues to determining the effect of disequilibrium processes on UHJs that are in general based on abundance and opacity measurements at different local times. It remains a challenge to completely disentangle this from the chemical effects of clouds and that of a primordial nonsolar abundance.
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Verma, M., C. Denker, A. Diercke, et al. "High-resolution spectroscopy of a surge in an emerging flux region." Astronomy & Astrophysics 639 (July 2020): A19. http://dx.doi.org/10.1051/0004-6361/201936762.
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Aims. The regular pattern of quiet-Sun magnetic fields was disturbed by newly emerging magnetic flux, which led a day later to two homologous surges after renewed flux emergence, affecting all atmospheric layers. Hence, simultaneous observations in different atmospheric heights are needed to understand the interaction of rising flux tubes with the surrounding plasma, in particular by exploiting the important diagnostic capabilities provided by the strong chromospheric Hα line regarding morphology and energetic processes in active regions. Methods. A newly emerged active region NOAA 12722 was observed with the Vacuum Tower Telescope (VTT) at Observatorio del Teide, Tenerife, Spain, on 11 September 2018. High spectral resolution observations using the echelle spectrograph in the chromospheric Hαλ6562.8 Å line were obtained in the early growth phase. Noise-stripped Hα line profiles yield maps of line-core and bisector velocities, which were contrasted with velocities inferred from Cloud Model inversions. A high-resolution imaging system recorded simultaneously broad- and narrowband Hα context images. The Solar Dynamics Observatory provided additional continuum images, line-of-sight (LOS) magnetograms, and UV and extreme UV (EUV) images, which link the different solar atmospheric layers. Results. The active region started as a bipolar region with continuous flux emergence when a new flux system emerged in the leading part during the VTT observations, resulting in two homologous surges. While flux cancellation at the base of the surges provided the energy for ejecting the cool plasma, strong proper motions of the leading pores changed the magnetic field topology making the region susceptible to surging. Despite the surge activity in the leading part, an arch filament system in the trailing part of the old flux remained stable. Thus, stable and violently expelled mass-loaded ascending magnetic structures can coexist in close proximity. Investigating the height dependence of LOS velocities revealed the existence of neighboring strong up- and downflows. However, downflows occur with a time lag. The opacity of the ejected cool plasma decreases with distance from the base of the surge, while the speed of the ejecta increases. The location at which the surge becomes invisible in Hα corresponds to the interface where the surge brightens in He IIλ304 Å. Broad-shouldered and dual-lobed Hα profiles suggests accelerated or decelerated and highly structured LOS plasma flows. Significantly broadened Hα profiles imply significant heating at the base of the surges, which is also supported by bright kernels in UV and EUV images uncovered by swaying motions of dark fibrils at the base of the surges. Conclusions. The interaction of newly emerging flux with pre-existing flux concentrations of a young, diffuse active region provided suitable conditions for two homologous surges. High-resolution spectroscopy revealed broadened and dual-lobed Hα profiles tracing accelerated or decelerated flows of cool plasma along the multi-threaded structure of the surge.
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Gong, Sheng, Huayao Chen, Xinhua Zhou, and Sundaram Gunasekaran. "Synthesis and applications of MANs/poly(MMA-co-BA) nanocomposite latex by miniemulsion polymerization." Royal Society Open Science 4, no. 11 (2017): 170844. http://dx.doi.org/10.1098/rsos.170844.
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We have synthesized core-shell structured 3-methacryloxypropyltrimethoxysilane (MPS) functionalized antimony-doped tin oxide nanoparticles (MANs)–poly(methyl methacrylate-co-butyl acrylate) (PMMA-co-BA, PMB) nanocomposite latex particles via miniemulsion polymerization method. Polymerizable anionic surfactant DNS-86 (allyloxy polyoxyethylene(10) nonyl ammonium sulfate) was first introduced to synthesize core-shell nanocomposite. The morphologies of synthesized MANs and MANs/PMB latex nanocomposite particles were studied with transmission electron microscopy, which revealed particles, on average 70 nm in size, with a core-shell structure. Owing to the uniformity and hydrophobicity of MANs, the MANs-embedded PMB latex nanocomposite can be tailored more precisely than other nanoparticles-embedded nanocomposites. Films incorporating 10 wt% of MANs in the MAN/PMB latex nanocomposite exhibit good transmittance in the visible region, and excellent opacity in the near infrared region. The MANs/PMB nanocomposite film also appears suitable for heat insulation applications.
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Faurobert, M., S. Criscuoli, M. Carbillet, and G. Contursi. "A new spectroscopic method for measuring the temperature gradient in the solar photosphere." Astronomy & Astrophysics 642 (October 2020): A186. http://dx.doi.org/10.1051/0004-6361/202037736.
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Context. The contribution of quiet-Sun regions to the solar irradiance variability is currently unclear. Certain solar-cycle variations of the quiet-Sun’s physical structure, such as the temperature gradient, might affect the irradiance. Accurate measurements of this quantity over the course of the activity cycle would improve our understanding of long-term irradiance variations. Aims. In a previous work, we introduced and successfully tested a new spectroscopic method for measuring the photospheric temperature gradient directly on a geometric scale in the case of non-magnetic regions. In this paper, we generalize this method for moderately magnetized regions that may be encountered in the quiet solar photosphere. Methods. To simulate spectroscopic observations, we used synthetic Stokes profiles I and V of the magnetic FeI 630.15 nm line and intensity profiles of the non-magnetic FeI 709 nm line computed from realistic three-dimensional magneto-hydrodynamical simulations of the photospheric granulation and line radiative transfer under local thermodynamical equilibrium conditions. We then obtained maps at different levels in the line-wings by convolution with the instrumental point spread function (PSF) under various conditions of atmospheric turbulence – with and without correction by an adaptive optics (AO) system. The PSF were obtained with the PAOLA software and the AO performance is inspired by the system that will be operating on the Daniel K. Inouye Solar Telescope. Results. We considered different conditions of atmospheric turbulence and photospheric regions with different mean magnetic strengths of 100 G and 200 G. As in non-magnetic cases studied in our previous work, the image correction by the AO system is mandatory for obtaining accurate measurements of the temperature gradient. We show that the non-magnetic line at 709 nm may be safely used in all the cases we have investigated. However, the intensity profile of the magnetic-sensitive line is broadened by the Zeeman effect, which would bias our temperature-gradient measurement. We thus implemented a correction procedure of the line profile for this magnetic broadening in the case of weakly magnetized regions. In doing so, we remarked that in the weak-field regime, the right- and left-hand (I + V and I − V) components have similar shapes, however, they are shifted in opposite directions due to the Zeeman effect. We thus reconstructed the intensity profile by shifting back the I + V and I − V profiles and by adding the re-centered profiles. The measurement then proceeds as in the non-magnetic case. We find that this correction procedure is efficient in regions where the mean magnetic strength is smaller or on the order of 100 G. Conclusions. The new method we implement here may be used to measure the temperature gradient in the quiet Sun from ground-based telescopes equipped with an efficient AO system. We stress that we derive the gradient on a geometrical scale and not on an optical-depth scale as we would do with other standard methods. This allows us to avoid any confusion due to the effect of temperature variations on the continuum opacity in the solar photosphere.
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Messaoudi, Leila. "Opacité et transparence dans les technolectes bilingues (français-arabe)." Meta 45, no. 3 (2002): 424–36. http://dx.doi.org/10.7202/003641ar.
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Résumé L'opacité des terminologies ne s'explique pas par des insuffisances inhérentes aux LS ouLC; elle proviendrait des pratiques traduisantes qui ont tendance à ne retenir que l'aspect générique des technolectes traduits, comme l'illustrent les échantillons empruntés aux domaines agricole et médical, donnant lieu à des confusions fâcheuses.Seule "une traduction conceptuelle (de "concept") [...] assurerait la "transparence " requise pour les technolectes ". "L'évaluation du degré de transparence du technolecte dans la LC consisterait à la fois à mesurer le degré d'appropriation du concept via la LS mais aussi le taux de stratégies d'adéquation mises en œuvre par l'exploitation de moyens propres dont toute langue dispose".
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Rialland, Ivanne. "« Je serai trappeur, mineur… »." Études littéraires 44, no. 1 (2013): 67–79. http://dx.doi.org/10.7202/1018466ar.
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Résumé Perçus à l’époque comme typiques du « nouveau mal du siècle », tel que le nomme en 1924 Arland dans La Nouvelle revue française, les romans de Soupault mettent en leur coeur l’aventure pour montrer l’impossible adhésion au monde de l’homme occidental moderne : l’homme blanc n’y trouve qu’ennui tandis que l’écriture romanesque empêche tout départ véritable en perpétuant la chaîne des souvenirs. Il ne reste au romancier qu’à se faire le témoin émerveillé de l’énergie de l’homme noir. Celui-ci introduit non seulement dans la prose narrative un autre rapport au monde et au temps, mais ce faisant bouleverse l’écriture en la fragmentant : au lieu de dissoudre le réel dans le souvenir et l’ennui, la prose parvient alors à lui rendre son opacité signifiante.
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Pain, Jean-Christophe. "L’hélio-sismologie et l’énigme de l’opacité du fer." Reflets de la physique, no. 58 (June 2018): 10–15. http://dx.doi.org/10.1051/refdp/201858010.
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La mesure du spectre de pulsations d’une étoile permet d’obtenir des informations sur les processus physiques qui régissent sa structure et son évolution. La révision récente des abondances chimiques solaires entraîne un désaccord entre le modèle stellaire standard et les mesures d’hélio-sismologie. L’opacité du fer a été mesurée en laboratoire, dans des conditions proches de celles de l’interface entre les zones radiative et convective du Soleil. Les opacités déduites des mesures sont, dans une gamme spectrale allant de 7 à 12,7 Å, de 30 à 400 % supérieures aux calculs, ce qui tend à réconcilier mesures hélio-sismiques et prédictions du modèle standard, mais demeure une énigme pour les théoriciens.
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Wiesner. "Stellenwert radiologischer Bildgebung nach laparoskopischem Gastric Banding." Praxis 91, no. 31 (2002): 1246–55. http://dx.doi.org/10.1024/0369-8394.91.31.1246.
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Durant les dernières années, le banding gastrique par laparoscopie est devenu une des opérations les plus courantes pour le traitement de patients avec une polyphagie pathologique. Deux systèmes sont utilisés dans le monde: Le LAP BAND (ASGB – Adjustable Silicone Gastric Banding) et le banding suédois (SAGB – Swedish Adjustable Gastric Banding) qui sont tous les deux implantés par laparoscopie dans la partie proximale de l'estomac environ 2 cm distalement du cardia de façon suprabursale pour diminuer le volume fonctionnel de l'estomac et stimuler ainsi un sentiment de satiété. Les deux systèmes se différencient par leur consistance, leur opacité radiologique et leur dimension, mais les mécanismes d'action et les principes techniques d'implantation de banding, d'ajustement de la lumière de l'estomac ainsi que de la perte de poids postopératoire et des contrôles radiologiques sont similaires pour les deux systèmes. Bien que les patients avec un banding de l'estomac peuvent être pris en charge complètement par les cliniciens, il est établi que des contrôles radiologiques sont indispensables non seulement pour une régulation exacte de la lumière de l'estomac mais aussi pour la perte de poids postopératoire optimale et la mise en évidence de complications postopératoires éventuelles. Ce travail décrit l'image radiologique des deux systèmes, la prise en charge radiologique de ce collectif de patients et présente un aperçu des complications postopératoires connues et quelques recommandations concernant l'approche thérapeutique.
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Carballo, Pablo Zambrano. "La vraisemblance linguistique: réflexions autour de la traduction du lexique balzacien." Babel. Revue internationale de la traduction / International Journal of Translation 58, no. 4 (2012): 423–42. http://dx.doi.org/10.1075/babel.58.4.04zam.
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Balzac’s realistic technique relies mainly on the verisimilitude of a huge variety of elements (characters, descriptions, encyclopedic knowledge, etc.), among which language stands out as one of the mainstays of La Comedie humaine in general and Illusions perdues — the key novel — in particular. This paper highlights first the crucial role of Balzac’s singular vocabulary (technical terms, slang words, etc.) for the success of his ambitious realist project, the variety and complexity of his language being a reflection of the variety and complexity of the new society he aims to describe. Then, through a comparative study of a group of English and Spanish translations of Illusions perdues, the paper insists on the importance of consciously maintaining Balzac’s complex lexical singularities in the target languages, this being the only way to offer the reader a text faithful to the realistic intentions of his author instead of a modern “dubbed” easier-tounderstand version. Résumé Le realisme de Balzac etant fonde dans une grande mesure sur la vraisemblance d’un ensemble d’elements divers (personnages, descriptions, encyclopedisme, etc.), la creation d’une ecriture de nature a reveler et dessiner avec exactitude et finesse cette vraisemblance generale, deviennent les objectifs primordiaux du romancier dans La Comedie humaine et plus particulierement dans Illusions perdues, le roman capital. Cet article souligne d’une part, la fonction decisive du lexique singulier (termes techniques, argot propre aux divers tissus sociaux, etc.) necessaire au succes du projet realiste de Balzac, puisque la variete du vocabulaire et la complexite de la plume balzacienne repondent parfaitement a la variete et a la complexite de la nouvelle societe qu’il depeint. D’autre part, l’analyse contrastive de diverses traductions d’Illusions perdues en anglais et en espagnol nous permet de comprendre et de souligner l’importance de transposer consciemment dans les langues d’arrivee les singularites lexicales balzaciennes et leur opacite originale si l’on veut offrir au lecteur etranger non pas un texte ≪ double ≫ dans une langue contemporaine plus comprehensible, mais un texte vraisemblable et donc fidele a l’ambitieuse volonte de Balzac de portraiter avec realisme la societe de son epoque.
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Dellazzana, Fernando Zurlo, Camila Silva Rodrigues, André Mallmann, and Letícia Borges Jacques. "Optical Properties of a Glass Ceramic and an Indirect Resin Composite: Effects of Polishing and Staining." Journal of Health Sciences 21, no. 5 (2019): 512–17. http://dx.doi.org/10.17921/2447-8938.2019v21n5p512-517.
Full textAbstract:
AbstractLittle information is available about the optical behavior of glass ceramics and indirect resin composites. This study aimed to evaluate if an indirect resin composite can present similar behavior of color stability and translucency to a glass ceramic after polishing and aging in staining beverage. Specimens of a dental ceramic (IPS e.max Ceram) and an indirect resin composite (SR Adoro) were made. Half the specimens of each material were polished with disc-shaped tips. Groups were divided according to aging media: distilled water or immersion in red wine for 20 min/day during 30 days. CIE L*a*b* coordinates were measured with a spectrophotometer at baseline and after 30 days of aging. Color change was calculated by CIEDE2000 and translucency was calculated by contrast ratio (CR). Statistical analysis were performed with ANOVA and Tukey tests. Aging in red wine caused perceptible color change in both materials. Polishing only increased color change of indirect composite when aged in red wine. Ceramic groups showed greater opacity than the composite in all measurements. The indirect composite remained more translucent and results showed that it is capable of presenting color stability similar to a ceramic. However, polishing seems to increase its color change. Keywords: Ceramics. Color. Composite Resins. Dental Polishing. ResumoPouca informação comparando o comportamento óptico de cerâmicas vítreas e resinas compostas indiretas estão disponíveis na literatura. O objetivo deste estudo foi avaliar se uma resina composta indireta pode apresentar comportamento semelhante a uma cerâmica vítrea em relação à estabilidade de cor e translucidez após polimento e envelhecimento em meio altamente pigmentante. Espécimes de uma cerâmica vítrea (IPS e.max Ceram) e uma resina composta indireta (SR Adoro) foram preparados. Metade dos espécimes de cada material foram polidas com pontas de polimento. Os grupos foram divididos conforme o meio de armazenamento: água destilada ou vinho tinto por 20 min/dia durante 30 dias. As coordenadas CIEL*a*b* foram medidas com espectrofotômetro previamente e após os 30 dias de armazenamento. A alteração de cor foi calculada pela equação CIEDE2000 e a translucidez foi calculada por razão de contraste. A análise estatística foi realizada pelos testes ANOVA e teste de Tukey. O armazenamento em vinho levou a uma alteração de cor perceptível nos dois materiais. O polimento apenas causou alteração de cor na resina composta indireta quando imersa em vinho tinto. A resina composta indireta manteve-se mais translúcida e os resultados mostraram que esse material é capaz de apresentar estabilidade de cor semelhante à cerâmica. No entanto, o polimento parece aumentar sua alteração de cor. Palavras-chave: Cerâmica. Cor. Polimento Dentário. Resinas Compostas.
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Bendada, A., S. Sfarra, C. Ibarra−Castanedo, et al. "Subsurface imaging for panel paintings inspection: A comparative study of the ultraviolet, the visible, the infrared and the terahertz spectra." Opto-Electronics Review 23, no. 1 (2015). http://dx.doi.org/10.1515/oere-2015-0013.
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AbstractInfrared (IR) reflectography has been used for many years for the detection of underdrawings on panel paintings. Advances in the fields of IR sensors and optics have impelled the wide spread use of IR reflectography by several recognized Art Museums and specialized laboratories around the World. The transparency or opacity of a painting is the result of a complex combination of the optical properties of the painting pigments and the underdrawing material, as well as the type of illumination source and the sensor characteristics. For this reason, recent researches have been directed towards the study of multispectral approaches that could provide simultaneous and complementary information of an artwork. The present work relies on non−simultaneous multispectral inspection using a set of detectors covering from the ultraviolet to the terahertz spectra. It is observed that underdrawings contrast increases with wavelength up to 1700 nm and, then, gradually decreases. In addition, it is shown that IR thermography, i.e., temperature maps or thermograms, could be used simultaneously as an alternative technique for the detection of underdrawings besides the detection of subsurface defects.
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Park, Beomhee, Yongwon Cho, Gaeun Lee, et al. "A Curriculum Learning Strategy to Enhance the Accuracy of Classification of Various Lesions in Chest-PA X-ray Screening for Pulmonary Abnormalities." Scientific Reports 9, no. 1 (2019). http://dx.doi.org/10.1038/s41598-019-51832-3.
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Abstract We evaluated the efficacy of a curriculum learning strategy using two steps to detect pulmonary abnormalities including nodule[s], consolidation, interstitial opacity, pleural effusion, and pneumothorax with chest-PA X-ray (CXR) images from two centres. CXR images of 6069 healthy subjects and 3417 patients at AMC and 1035 healthy subjects and 4404 patients at SNUBH were obtained. Our approach involved two steps. First, the regional patterns of thoracic abnormalities were identified by initial learning of patch images around abnormal lesions. Second, Resnet-50 was fine-tuned using the entire images. The network was weakly trained and modified to detect various disease patterns. Finally, class activation maps (CAM) were extracted to localise and visualise the abnormal patterns. For average disease, the sensitivity, specificity, and area under the curve (AUC) were 85.4%, 99.8%, and 0.947, respectively, in the AMC dataset and 97.9%, 100.0%, and 0.983, respectively, in the SNUBH dataset. This curriculum learning and weak labelling with high-scale CXR images requires less preparation to train the system and could be easily extended to include various diseases in actual clinical environments. This algorithm performed well for the detection and classification of five disease patterns in CXR images and could be helpful in image interpretation.
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Dubost, Jean-pierre. "Orient désorienté." Anthropen, 2016. http://dx.doi.org/10.17184/eac.anthropen.022.
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« Les Orients désorientés » (Dubost Gasquet 2013) est un enjeu de méthode exprimé par un jeu de langage dont le but est de laisser entendre une démarche choisie pour aborder et repenser l’opposition Orient/Occident. Si le premier terme – l’Orient - est contre toute habitude au pluriel, et si ce à quoi on s’attend qu’il s’oppose - l’Occident - est occulté par ce qui engendre à la fois un pluriel et un négatif, c’est qu’il ne s’agit pas d’un couple de notions, ni même d’un couple d’oppositions. En se glissant dans les interstices de l’« antithèse durcie » (A. Memmi) Orient/occident, la formule annonce que la relation qu’il s’agit de rechercher n’est ni donnée ni héritée. En revanche, la démarche reste redevable de cette sorte de grand écart qui habite l’œuvre riche et contradictoire d’Edward Said dans Orientalism (1978). Si la thèse essentielle est que le développement de l’orientalisme européen a été indissociablement lié au processus de la colonisation dont il n’a été que l’expression littéraire ou artistique, Said exprime clairement à la fin de sa vie la nécessité de penser, non pas contre mais au-delà de la thèse critique qui animait son ouvrage fondateur, cette question en terme de relation, au sens qu’Edouard Glissant (1990) donne au terme. L’écrivain écrit dans la préface de la réédition française de L’Orientalisme (Said 2003 : p. IX) que « loin du choix des civilisations, nous devons nous concentrer sur un long travail en commun de cultures qui se chevauchent, empruntent les unes aux autres et cohabitent de manière bien plus profonde que ne le laissent penser des modes de compréhension réducteurs et inauthentiques » et que « cette forme de perception plus large exige du temps, des recherches patientes et toujours critiques, alimentées par la foi et une communauté intellectuelle difficile à conserver dans un monde fondé sur l’immédiateté de l’action et de la réaction ». Opérer un retour réflexif sur cette question clairement exposée comme un programme encore à réaliser conduit à déconstruire les concepts à partir desquels la relation Orient/Occident a été historiquement pensée et à demander en quoi et comment elle est pensable une fois reconnue l’urgente nécessité d’une dés-essentialisation des deux termes de l’opposition. Ce questionnement coïncide avec un retour du questionnement de la relation Orient/Occident dans la communauté scientifique (Courbage, Kropp 2004 ; Combe, Lançon, Moussa et Murat 2008-2012 ; F. Pouillon, J.C. Vatin 2012 ; A. Gasquet 2010 ; Ette, Kennewick 2006 etc.) exprimant le besoin d’une relecture de la relation Orient/occident non seulement dans sa configuration d’aujourd’hui (pour laquelle la désorientation de l’Orient est indissociable du processus de mondialisation et de redistribution généralisée de toutes les instances et figures d’identification et de référence) mais aussi au cœur même de la relation orientale en tant que moment du processus colonial, avec ses nombreuses ambivalences et lignes de fuites internes. Si l’Orient n’est plus aujourd’hui une notion pertinente (pas plus qu’il n’est simple et facile de définir « l’essence » de l’Occident) et s’il est acquis que supposer une altérité orientale absolue ne ferait que perpétuer une idéologie née dans le contexte de la conquête coloniale du monde (de la fin du XVe siècle au milieu du XXe), c’est qu’il est lui-même, comme nous le montre à l’évidence la situation d’aujourd’hui, dés-orienté. Et si l’opposition Orient/Occident est devenue caduque dans le monde actuel, c’est que les relations transculturelles ne peuvent plus être comprises comme des oppositions identitaires d’ordre binaire, mais comme autant de structures paradoxales de relation. Les outils de compréhension à partir desquels ils peuvent et doivent être pensés sont nombreux : les avancées les plus récentes de l’anthropologie critique et de son interrogation des conditions méthodologique d’une pensée hégémonique (Saillant, Kilani, Graezer Bideau 2011), l’apparition de modèles paradoxaux d’universalité issus de cultures périphériques, les expérimentations de devenirs personnels à la charnière de l’Orient et de l’Occident et autres phénomènes. Analyser dans le processus de mondialisation des figures de relation transculturelle éclairant la dés-essentialisation de la relation Orient/Occident suppose que l’on accepte l’idée qu’une opacité irréductible détermine le rapport des cultures mondialement emmêlées et que celle-ci surplombe les représentations mutuelles que les protagonistes de cette relation peuvent s’en faire. Cette opacité n’est pas un frein mais un moteur de rencontre. Il s’agit donc de décrypter le processus de ‘mondialisation’ à la recherche de traces oubliées ou impensées, faute d’outils d’analyse comparative. Les événements politiques les plus récents comme le ‘printemps arabe’, le processus inéluctable de ré-Orientation de l’Orient depuis la Nahdha arabe au XIXe, les inévitables « dé-exotisations » modernes japonaise ou chinoise, la ‘perlaboration’ par laquelle les élites du sous-continent indien se positionnent au-delà des méandres idéologiques de l’héritage postcolonial en sont autant d’expressions. Mais cette approche implique aussi la nécessité de problématiser l’impensé de la relation Orient/Occident dans le passé et d’approfondir par l’analyse les tentatives déjà faites en ce sens, notamment par Jack Goody (1999, 2004, 2006). L'enjeu de recherche « Orients désorientés » conduit à générer autant de multiples que la dés-essentialisation des deux termes permet de dégager et se donne pour but de laisser apparaître tout ce que cette essentialisation occulte. On peut alors décliner la relation libérée de son statut d’opposition stérile en autant de figures de relations orientalo-occidentales, de configurations engendrées par l’attitude plus ou moins hospitalière d’un regard porté sur son être-différent, son « otherness ». Par exemple : un « Orient pour soi » qui serait préservé de rencontres et de contaminations, objet historiquement rarissime si ce n’est introuvable ; un « Orient pour nous » comme construction imaginaire occidentale ; un « Orient pour nous » comme part refoulée de l’histoire de l’Occident (origines religieuses sémites, origine philosophique, rationaliste et métaphysique gréco-arabe de l’Occident médiéval puis renaissant) ; un « Orient pour nous » comme expérience de pensée, d’imagination et d’écriture maintenant en elle-même consciemment le moment de la rencontre et de l’ouverture comme ingrédient de l’identification orientale (Novalis, Goethe, Schelling, Schopenhauer etc.) ; un Orient assimilé et approprié, mais dont l’altérité résiste au cœur de la relation dominante comme singularité – au cœur même parfois de ces orientalismes dont la définition ne peut pas se limiter à la seule perspective critique de type saïdienne ; un Orient distancié de l’intérieur par de nouvelles différenciations (« Orients de l’Orient », comme c’est le cas du soufisme dans l’aire arabo-islamique) ; un Orient rencontré comme autre autrement que par un Occident européen et perçu comme objet d’altérité différent (c’est le cas des orientalismes sud-américains) ; un Orient rencontré dans le cadre d’un processus colonial, dont la différence est perçue et vécue au cœur même d’une situation de domination, bien que cette perception ne concorde pas avec le « style occidental de domination, de restructuration et d’autorité sur l’Orient » – celle-là même que Said analyse et dénonce à la fois, et dont la figuration surgit comme ligne de fuite interne à ce même processus comme ce fut le cas chez Victor Segalen envers la Chine, mais chez d’autres encore, et ainsi de suite à l’infini.