1,235 research outputs found

    The Alhambra, an Islamic palace

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    En este artículo se emplea una variedad de textos con el fin de proponer una nueva lectura de la dama de las pinturas de la la llamada “Sala de la Justicia”, que la vincula con el proyecto de auto-representación de la dinastía nazarí a través de un idioma simbólico que incluye, además de la propia dama, los árboles, la vegetación, los jardines y evocaciones de la familia del Profeta Mahoma. Se propone que el significado simbólico otorgado a la dama por los nazaríes se relaciona con la importancia ortogada a la Virgen en las cortes cristianas con las que los nazaríes estaban en contacto.This article employs a variety of texts in order to propose a new reading of the Lady of the so-called “Hall of Justice” paintings which links her to a project of Nasrid dynastic self-representation involving, in addition to the Lady herself, trees, vegetation, gardens and evocations of the family of the Prophet Muhammad. It is proposed that the symbolic significance accorded to the Lady by the Nasrids is related to the importance of the Virgin at Christian courts with which the Nasrids were in contact

    WALK ON - From Richard Long to Janet Cardiff - 40 years of Art Walking

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    This is the first exhibition to examine the many and varied ways in which artists since the late 1960s have used what would seem like a universal act – that of taking a walk – as a means to create new types of art. ‘Walk On’ includes photography, film, and installation works, bringing together a diverse group of artists inspired by their travels on foot. It offers an as-yet-unwritten history of a major strand of recent art practice. It argues that from land art and conceptual art, and from street photography to the essay-film, an exceptionally wide range of first-rate artists have created their work from the act of walking, in the city or the land

    Blending the Old and the New: Qualitative Data Analysis a s Critical Thinking and Using NVivo with a Generic Approach

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    In this article the authors seek to make the case that qualitative data analysis can be explained within the framework of critical thinking and incorporates within this framework the role of technology – specifically NVivo. First they discuss critical thinking from the perspectives of Bloom, Adler, and Polanyi. They then link critical thinking to the concept of a general inductive approach to qualitative analysis as described by Thomas. Finally, they illustrate connections of both critical thinking and the general inductive approach to technology using NVivo screenshots

    The Mass of the Black Hole in XTE J1118+480

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    We present contemporaneous, broadband, near-infrared spectroscopy (0.9-2.45 μm) and H-band photometry of the black hole X-ray binary, XTE J1118+480. We determined the fractional dilution of the NIR ellipsoidal light curves of the donor star from other emission sources in the system by comparing the absorption features in the spectrum with field stars of known spectral type. We constrained the donor star spectral type to K7 V-M1 V and determined that the donor star contributed 54% ± 27% of the H-band flux at the epoch of our observations. This result underscores the conclusion that the donor star cannot be assumed to be the only NIR emission source in quiescent X-ray binaries. The H-band light curve shows a double-humped asymmetric modulation with extra flux at orbital phase 0.75. The light curve was fitted with a donor star model light curve, taking into account a constant second flux component based on the dilution analysis. We also fitted models that included emission from the donor star, a constant component from the accretion disk, and a phase-variable component from the bright spot where the mass accretion stream impacts the disk. These simple models with reasonable estimates for the component physical parameters can fully account for the observed light curve, including the extra emission at phase 0.75. From our fits, we constrained the binary inclination to 68° ≤ i ≤ 79°. This leads to a black hole mass of 6.9 M_☉ ≤ M_(BH) ≤ 8.2 M_☉. Long-term variations in the NIR light curve shape in XTE J1118+480 are similar to those seen in other X-ray binaries and demonstrate the presence of continued activity and variability in these systems even when in full quiescence

    Near-Infrared Light Curves of the Black Hole Binary A0620-00

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    We measured the near-infrared orbital light curve of the black hole binary A0620-00 in 1995 and 1996. The light curves show an asymmetric, double-humped modulation with extra emission in the peak at orbital phase 0.75. There were no significant changes in the shape of the light curve over the one-year observation period. There were no sharp dips in the light curves nor reversals of the asymmetry between the two peaks as seen in earlier observations. The light curves are well fit by models incorporating ellipsoidal variations from the mass-losing K-type star plus a beamed bright spot on the accretion disk around the compact star. The long-term stability of the light curve shape rules out superhumps and star spots as sources of asymmetry when we observed A0620-00. The ellipsoidal variations yield a lower limit i >= 38 deg on the orbital inclination. The light curves show no eclipse features, which places an upper limit i <= 75 deg. This range of inclinations constrains the mass of the compact object to 3.3 < M_1 < 13.6 Msun. The light curves do not further constrain the orbital inclination because the contribution of the accretion disk to the observed flux is unknown. We argue that a previous attempt to measure the near-infrared flux from the accretion disk using the dilution of the 12CO(2,0) bandhead in the spectrum of the K star is not reliable because the band strength depends strongly on surface gravity.Comment: Accepted for publication in the Astronomical Journal. 17 pages, 4 figures. Prepared using AASTEX V. 5.

    Research on the International Space Station - An Overview

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    The International Space Station (ISS) celebrates ten years of operations in 2008. While the station did not support permanent human crews during the first two years of operations November 1998 to November 2000 it hosted a few early science experiments months before the first international crew took up residence. Since that time and simultaneous with the complicated task of ISS construction and overcoming impacts from the tragic Columbia accident science returns from the ISS have been growing at a steady pace. As of this writing, over 162 experiments have been operated on the ISS, supporting research for hundreds of ground-based investigators from the U.S. and international partners. This report summarizes the experimental results collected to date. Today, NASA's priorities for research aboard the ISS center on understanding human health during long-duration missions, researching effective countermeasures for long-duration crewmembers, and researching and testing new technologies that can be used for future exploration crews and spacecraft. Through the U.S. National Laboratory designation, the ISS is also a platform available to other government agencies. Research on ISS supports new understandings, methods or applications relevant to life on Earth, such as understanding effective protocols to protect against loss of bone density or better methods for producing stronger metal alloys. Experiment results have already been used in applications as diverse as the manufacture of solar cell and insulation materials for new spacecraft and the verification of complex numerical models for behavior of fluids in fuel tanks. A synoptic publication of these results will be forthcoming in 2009. At the 10-year point, the scientific returns from ISS should increase at a rapid pace. During the 2008 calendar year, the laboratory space and research facilities were tripled with the addition of ESA's Columbus and JAXA's Kibo scientific modules joining NASA's Destiny Laboratory. All three laboratories, together with external payload accommodations, support a wide variety of research racks and science and technology experiments. In 2009, the number of crewmembers will increase from three to six, greatly increasing the time available for research. The realization of the international scientific partnership provides new opportunities for scientific collaboration and broadens the research potential on the ISS. Engineers and scientists from around the world are working together to refine their operational relationships and build from their experiences conducting early science to ensure maximum utilization of the expanded capabilities aboard ISS. This paper will summarize science results and accomplishments, and discuss how the early science utilization provides the foundation for continuing research campaigns aboard the ISS that will benefit future exploration programs

    Spectroscopy of Nine Cataclysmic Variable Stars

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    We present optical spectroscopy of nine cataclysmic binary stars, mostly dwarf novae, obtained primarily to determine orbital periods Porb. The stars and their periods are LX And, 0.1509743(5) d; CZ Aql, 0.2005(6) d; LU Cam, 0.1499686(4) d; GZ Cnc, 0.0881(4) d; V632 Cyg, 0.06377(8) d; V1006 Cyg, 0.09903(9) d; BF Eri, 0.2708804(4) d; BI Ori, 0.1915(5) d; and FO Per, for which Porb is either 0.1467(4) or 0.1719(5) d. Several of the stars proved to be especially interesting. In BF Eri, we detect the absorption spectrum of a secondary star of spectral type K3 +- 1 subclass, which leads to a distance estimate of approximately 1 kpc. However, BF Eri has a large proper motion (100 mas/yr), and we have a preliminary parallax measurement that confirms the large proper motion and yields only an upper limit for the parallax. BF Eri's space velocity is evidently large, and it appears to belong to the halo population. In CZ Aql, the emission lines have strong wings that move with large velocity amplitude, suggesting a magnetically-channeled accretion flow. The orbital period of V1006 Cyg places it squarely within the 2- to 3-hour "gap" in the distribution of cataclysmic binary orbital periods.Comment: 31 pages, 5 postscript and one PNG figure. Accepted for PAS

    Near-Infrared Spectroscopy of Low Mass X-ray Binaries : Accretion Disk Contamination and Compact Object Mass Determination in V404 Cyg and Cen X-4

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    We present near-infrared (NIR) broadband (0.80--2.42 μ\mum) spectroscopy of two low mass X-ray binaries: V404 Cyg and Cen X-4. One important parameter required in the determination of the mass of the compact objects in these systems is the binary inclination. We can determine the inclination by modeling the ellipsoidal modulations of the Roche-lobe filling donor star, but the contamination of the donor star light from other components of the binary, particularly the accretion disk, must be taken into account. To this end, we determined the donor star contribution to the infrared flux by comparing the spectra of V404 Cyg and Cen X-4 to those of various field K-stars of known spectral type. For V404 Cyg, we determined that the donor star has a spectral type of K3 III. We determined the fractional donor contribution to the NIR flux in the H- and K-bands as 0.98±.050.98 \pm .05 and 0.97±.090.97 \pm .09, respectively. We remodeled the H-band light curve from \citet{sanwal1996} after correcting for the donor star contribution to obtain a new value for the binary inclination. From this, we determined the mass of the black hole in V404 Cyg to be MBH=9.0.6+.2MM_{BH}= 9.0^{+.2}_{-.6}M_{\odot}. We performed the same spectral analysis for Cen X-4 and found the spectral type of the donor star to be in the range K5 -- M1V. The donor star contribution in Cen X-4 is 0.94±.140.94\pm.14 in the H-band while in the K-band, the accretion disk can contribute up to 10% of the infrared flux. We remodeled the H-band light curve from \citet{shahbaz1993}, again correcting for the fractional contribution of the donor star to obtain the inclination. From this, we determined the mass of the neutron star as MNS=1.5.4+.1MM_{NS}= 1.5^{+.1}_{-.4}M_{\odot}. However, the masses obtained for both systems should be viewed with some caution since contemporaneous light curve and spectral data are required to obtain definitive masses

    Granulocyte macrophage colony-stimulating factor receptor α expression and its targeting in antigen-induced arthritis and inflammation

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    A Representative FACS plots showing Ly6G and Ly6C staining of CD45+ myeloid populations in the AIA knee joint. F4/80intSSchi eosinophils (Eos), F4/80+CD11c+MHCII+ Mo-DCs (R1), F4/80+CD11c-MHCII+ macrophages (Macs) (R2), F4/80+CD11c-MHCII- macrophages (R3), F4/80-CD11c+ MHCII+ cDCs, F4/80-CD11b+Ly6G+ neutrophils, which are also Ly6C+, and F4/80-CD11b+Ly6G-SScloLy6C+/- monocytes. B Representative FACS plots of CD45+ myeloid populations in the AIA knee joint showing Ly6G+ neutrophils are CD64- and F4/80+ macrophages/Mo-DCs are CD64+. (PDF 235 kb
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