2,859 research outputs found

    A Catalog of Candidate Intermediate-luminosity X-ray Objects

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    ROSAT, and now Chandra, X-ray images allow studies of extranuclear X-ray point sources in galaxies other than our own. X-ray observations of normal galaxies with ROSAT and Chandra have revealed that off-nuclear, compact, Intermediate-luminosity (Lx[2-10 keV] >= 1e39 erg/s) X-ray Objects (IXOs, a.k.a. ULXs [Ultraluminous X-ray sources]) are quite common. Here we present a catalog and finding charts for 87 IXOs in 54 galaxies, derived from all of the ROSAT HRI imaging data for galaxies with cz <= 5000 km/s from the Third Reference Catalog of Bright Galaxies (RC3). We have defined the cutoff Lx for IXOs so that it is well above the Eddington luminosity of a 1.4 Msun black hole (10^38.3 erg/s), so as not to confuse IXOs with ``normal'' black hole X-ray binaries. This catalog is intended to provide a baseline for follow-up work with Chandra and XMM, and with space- and ground-based survey work at wavelengths other than X-ray. We demonstrate that elliptical galaxies with IXOs have a larger number of IXOs per galaxy than non-elliptical galaxies with IXOs, and note that they are not likely to be merely high-mass X-ray binaries with beamed X-ray emission, as may be the case for IXOs in starburst galaxies. Approximately half of the IXOs with multiple observations show X-ray variability, and many (19) of the IXOs have faint optical counterparts in DSS optical B-band images. Follow-up observations of these objects should be helpful in identifying their nature.Comment: 29 pages, ApJS, accepted (catalog v2.0) (full resolution version of paper and future releases of catalog at http://www.xassist.org/ixocat_hri

    Ultracold Atoms as a Target: Absolute Scattering Cross-Section Measurements

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    We report on a new experimental platform for the measurement of absolute scattering cross-sections. The target atoms are trapped in an optical dipole trap and are exposed to an incident particle beam. The exponential decay of the atom number directly yields the absolute total scattering cross-section. The technique can be applied to any atomic or molecular species that can be prepared in an optical dipole trap and provides a large variety of possible scattering scenarios

    Comparison of Prices and Affordability of Cancer Medicines in 16 Countries in Europe and Latin America

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    BACKGROUND: There are concerns that high prices of cancer medicines may limit patient access. Since information on prices for cancer medicines and their impact on affordability is lacking for several countries, particularly for lower income countries, this study surveys prices of originator cancer medicines in Europe and Latin America and assesses their affordability. METHODS: For 19 cancer medicines, public procurement and ex-factory prices, as of 2017, were surveyed in five Latin American (LATAM) countries (Brazil, Chile, Colombia, Mexico, and Peru) and 11 European countries (Austria, France, Germany, Greece, Hungary, the Netherlands, Poland, Romania, Spain, Sweden, and the UK). Price data (public procurement prices in LATAM and ex-factory prices in Europe) in US dollar purchasing power parities (PPP) were analyzed per defined daily dose. Affordability was measured by setting medicines prices in relation to national minimum wages. RESULTS: The prices of cancer medicines varied considerably between countries. In European countries with higher levels of income, PPP-adjusted prices tended to be lower than in European countries of lower income and LATAM countries. Except for one medicine, all surveyed medicines were considered unaffordable in most countries. In European countries of lower income and LATAM countries, more than 15 days’ worth of minimum wages would be required by a worker to purchase one defined daily dose of several of the studied medicines. CONCLUSIONS: The high prices and large unaffordability of cancer medicines call for strengthening pricing policies with the aim of ensuring affordable treatment in cancer care. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40258-021-00670-4

    Re-evaluation of the 1950?1962 total ozone record from Longyearbyen, Svalbard

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    International audienceThe historical total ozone measurements taken with Dobson Spectrophotometer #8 at Longyearbyen (78.2° N, 15.6° E), Svalbard, Norway, in the period 1950?1962 have been re-analyzed and homogenized based on the original measurement logs, using present-day procedures. In lack of sufficient calibration information, an empirical quality assessment was performed, based on a climatological comparison with ozone measurements in Tromsø, using TOMS data at both sites in the period 1979?2001, and ground-based Dobson data in the period 1950?1962. The assessment revealed that the C wavelength pair direct-sun (DS) measurements are most trustworthy (and most frequent), while the WMO standard reference mode AD direct-sun has a systematic bias. Zenith-blue (ZB) measurements at solar zenith angles (SZA) <78° were adjusted to DS data using different empirical functions before and after 1957 (the start of the International Geophysical Year). ZB measurements at larger SZAs were homogenized by means of a normalization function derived from days with measurements over a wide range of SZAs. Zenith-cloudy measurements, which are particularly frequent during the summer months, were homogenized by applying correction factors depending on the cloud type (high thin clouds and medium to low thick clouds). The combination of all measurements yields a total of 4685 single values, covering 1637 days from September 1950 to September 1962; moon measurements during the polar night add another 137 daily means. The re-evaluated data show a convincing consistence with measurements since 1979 (TOMS, SAOZ, Dobson) as well as with the 1957?1962 data stored at the World Ozone and UV Data Centre (WOUDC)

    Robustness of a bisimulation-type faster-than preorder

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    TACS is an extension of CCS where upper time bounds for delays can be specified. Luettgen and Vogler defined three variants of bismulation-type faster-than relations and showed that they all three lead to the same preorder, demonstrating the robustness of their approach. In the present paper, the operational semantics of TACS is extended; it is shown that two of the variants still give the same preorder as before, underlining robustness. An explanation is given why this result fails for the third variant. It is also shown that another variant, which mixes old and new operational semantics, can lead to smaller relations that prove the same preorder.Comment: Express Worksho

    Dissecting the spiral galaxy M83: mid-infrared emission and comparison with other tracers of star formation

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    We present a detailed mid-infrared study of the nearby, face-on spiral galaxy M83 based on ISOCAM data. M83 is a unique case study, since a wide variety of MIR broad-band filters as well as spectra, covering the wavelength range of 4 to 18\mu m, were observed and are presented here. Emission maxima trace the nuclear and bulge area, star-formation regions at the end of the bar, as well as the inner spiral arms. The fainter outer spiral arms and interarm regions are also evident in the MIR map. Spectral imaging of the central 3'x3' (4 kpc x 4 kpc) field allows us to investigate five regions of different environments. The various MIR components (very small grains, polycyclic aromatic hydrocarbon (PAH) molecules, ionic lines) are analyzed for different regions throughout the galaxy. In the total 4\mu m to 18\mu m wavelength range, the PAHs dominate the luminosity, contributing between 60% in the nuclear and bulge regions and 90% in the less active, interarm regions. Throughout the galaxy, the underlying continuum emission from the small grains is always a smaller contribution in the total MIR wavelength regime, peaking in the nuclear and bulge components. The implications of using broad-band filters only to characterize the mid-infrared emission of galaxies, a commonly used ISOCAM observation mode, are discussed. We present the first quantitative analysis of new H-alpha and 6cm VLA+Effelsberg radio continuum maps of M83. The distribution of the MIR emission is compared with that of the CO, HI, R band, H-alpha and 6cm radio. A striking correlation is found between the intensities in the two mid-infrared filter bands and the 6cm radio continuum. To explain the tight mid-infrared-radio correlation we propose the anchoring of magnetic field lines in the photoionized shells of gas clouds.Comment: 22 pages, 15 figures. Accepted for publication in A&

    Independent evolution of sexual dimorphism and female-limited mimicry in swallowtail butterflies (Papilio dardanus and Papilio phorcas)

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    Several species of Swallowtail butterflies (genus Papilio) are Batesian mimics that express multiple mimetic female forms, while the males are monomorphic and non-mimetic. The evolution of such sex-limited mimicry may involve sexual dimorphism arising first and mimicry subsequently. Such a stepwise scenario through a non-mimetic, sexually dimorphic stage has been proposed for two closely related sexually dimorphic species; P. phorcas, a non-mimetic species with two female forms, and P. dardanus, a female-limited polymorphic mimetic species. Their close relationship indicates that female-limited polymorphism could be a shared derived character of the two species. Here we present a phylogenomic analysis of the dardanus group using 3964 nuclear loci and whole mitochondrial genomes showing that they are not sister species, and thus that the sexually-dimorphic state has arisen independently in the two species. Non-homology of the female polymorphism in both species is supported by population genetic analysis of engrailed, the presumed mimicry switch locus in P. dardanus. McDonald-Kreitman tests performed on SNPs in engrailed showed the signature of balancing selection in a polymorphic population of P. dardanus, but not in monomorphic populations, nor in the non-mimetic P. phorcas. Hence the wing polymorphism does not balance polymorphisms in engrailed in P. phorcas. Equally, unlike in P. dardanus, none of the SNPs in P. phorcas engrailed were associated with either female morph. We conclude that sexual dimorphism due to female polymorphism evolved independently in both species from monomorphic, non-mimetic states. While sexual selection may drive male-female dimorphism in non-mimetic species, in mimetic Papilios natural selection for protection from predators in females is an alternative route to sexual dimorphism

    Cicrumnuclear Supernova Remnants and HII Regions in NGC 253

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    Archival VLA data has been used to produce arcsecond-resolution 6- and 20-cm images of the region surrounding the nuclear 200-pc (~15") starburst in NGC 253. Twenty-two discrete sources stronger than 0.4 mJy have been detected within ~2 kpc (~3') of the galaxy nucleus; almost all these sources must be associated with the galaxy. None of the radio sources coincides with a detected X-ray binary, so they appear to be due to supernova remnants and H II regions. The region outside the central starburst has a derived radio supernova rate of <~0.1/yr, and may account for at least 20% of the recent star formation in NGC 253. Most of the newly identified sources have steep, nonthermal radio spectra, but several relatively strong thermal sources also exist, containing the equivalent of tens of O5 stars. These stars are spread over tens of parsecs, and are embedded in regions having average ionized gas densities of 20-200/cm^3, much lower than in the most active nuclear star-forming regions in NGC 253 or in the super star clusters seen in other galaxies. The strongest region of thermal emission coincides with a highly reddened area seen at near-infrared wavelengths, possibly containing optically obscured H II regions.Comment: 17 pages, 3 postscript figures, AASTeX format, in press for Astronomical Journal, July 200

    Engaging inhabitants into energy transition in climate and energy model (CEM) regions: case studies of Freistadt, Ebreichsdorf and Baden

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    Austria has settled a target to reach 34% of renewable energy sources in final energy consumption by 2020. The Climate and Energy Model (CEM) regions are the major vehicles for implementation of this target. Until now little research was done on existing participatory governance measures in the Austrian CEM regions, which involve not only stakeholders but also inhabitants into decision-making processes on energy transition. The aim of this paper is to collect information about existing participatory governance measures in three CEMs, such as Freistadt, Baden and Ebreichsdorf, and to analyze these measures by using methodologies developed by Arnstein in his ladder of participation. Our results show that the majority of existing measures are at the level of providing information and awareness building. However, there are also some measures, such as energy groups, which allow all interested inhabitants for providing feedback about proposed in their CEM projects. Other measures, such as Helios or Badener Sonnerkraft, allow for financial participation of inhabitants in deployment of renewable energy projects in their region
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