111 research outputs found

    Archaeological Survey of Sīnīya Island, Umm al-Quwain

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    The preliminary results of a comprehensive survey of Sīnīya Island in the Khawr al-Bayḍāʾ of Umm al-Quwain are presented here. The onset of human occupation remains to be confirmed, with scarce evidence for limited activity in the late pre-Islamic period (LPI, c. 300 BC – AD 300). The first major phase of occupation dates to the seventh and eighth centuries (early Islamic period) when a monastery and settlement were established in the north-east of the island. Probably the peak occupation falls between the fourteenth and fifteenth centuries, when the stone-town of Old Umm al-Quwain 1 was built, followed by the eighteenth to early nineteenth century when the settlement moved to neighbouring Old Umm al-Quwain 2. The town was destroyed by the British in 1820 and moved to the facing tidal island, where Old Umm al-Quwain 3 (the modern city of the same name) developed. This resulted in an emptying of the landscape, and Sīnīya Island was little visited in the nineteenth and twentieth centuries, except for the estate of the ruling Āl Muʿallā represented by the Mallāh Towers.The preliminary results of a comprehensive survey of Sīnīya Island in the Khawr al-Bayḍāʾ of Umm al-Quwain are presented here. The onset of human occupation remains to be confirmed, with scarce evidence for limited activity in the late pre-Islamic period (LPI, c. 300 BC – AD 300). The first major phase of occupation dates to the seventh and eighth centuries (early Islamic period) when a monastery and settlement were established in the north-east of the island. Probably the peak occupation falls between the fourteenth and fifteenth centuries, when the stone-town of Old Umm al-Quwain 1 was built, followed by the eighteenth to early nineteenth century when the settlement moved to neighbouring Old Umm al-Quwain 2. The town was destroyed by the British in 1820 and moved to the facing tidal island, where Old Umm al-Quwain 3 (the modern city of the same name) developed. This resulted in an emptying of the landscape, and Sīnīya Island was little visited in the nineteenth and twentieth centuries, except for the estate of the ruling Āl Muʿallā represented by the Mallāh Towers

    QUIJOTE scientific results -- XIII. Intensity and polarization study of supernova remnants in the QUIJOTE-MFI wide survey: CTB 80, Cygnus Loop, HB 21, CTA 1, Tycho and HB 9

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    We use the new QUIJOTE-MFI wide survey (11, 13, 17 and 19 GHz) to produce spectral energy distributions (SEDs), on an angular scale of 1 deg, of the supernova remnants (SNRs) CTB 80, Cygnus Loop, HB 21, CTA 1, Tycho and HB 9. We provide new measurements of the polarized synchrotron radiation in the microwave range. For each SNR, the intensity and polarization SEDs are obtained and modelled by combining QUIJOTE-MFI maps with ancillary data. In intensity, we confirm the curved power law spectra of CTB 80 and HB 21 with a break frequency νb\nu_{\rm b} at 2.00.5+1.2^{+1.2}_{-0.5} GHz and 5.01.0+1.2^{+1.2}_{-1.0} GHz respectively; and spectral indices respectively below and above the spectral break of 0.34±0.04-0.34\pm0.04 and 0.86±0.5-0.86\pm0.5 for CTB 80, and 0.24±0.07-0.24\pm0.07 and 0.60±0.05-0.60\pm0.05 for HB 21. In addition, we provide upper limits on the Anomalous Microwave Emission (AME), suggesting that the AME contribution is negligible towards these remnants. From a simultaneous intensity and polarization fit, we recover synchrotron spectral indices as flat as 0.24-0.24, and the whole sample has a mean and scatter of 0.44±0.12-0.44\pm0.12. The polarization fractions have a mean and scatter of 6.1±1.96.1\pm1.9\%. When combining our results with the measurements from other QUIJOTE studies of SNRs, we find that radio spectral indices are flatter for mature SNRs, and particularly flatter for CTB 80 (0.240.06+0.07-0.24^{+0.07}_{-0.06}) and HB 21 (0.340.03+0.04-0.34^{+0.04}_{-0.03}). In addition, the evolution of the spectral indices against the SNRs age is modelled with a power-law function, providing an exponent 0.07±0.03-0.07\pm0.03 and amplitude 0.49±0.02-0.49\pm0.02 (normalised at 10 kyr), which are conservative with respect to previous studies of our Galaxy and the Large Magellanic Cloud.Comment: 33 pages, 15 figure, 15 tables. Submitted to MNRAS. QUIJOTE data maps available at https://research.iac.es/proyecto/quijot

    Books in Arabic Script

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    The chapter approaches the book in Arabic script as the indispensable means for the transmission of knowledge across Eurasia and Africa, within cultures and across cultural boundaries, since the seventh century ad. The state of research can be divided into manuscript and print studies, but there is not yet a history of the book in Arabic script that captures its plurilinear development for over fourteen hundred years. The chapter explores the conceptual and practical challenges that impede the integration of the book in Arabic script into book history at large and includes an extensive reference list that reflects its diversity. The final published version was slightly updated, and includes seven illustrations of six Qurans from the holdings of Columbia University Libraries, four manuscripts and two printed versions. Moreover, the illustrations are images of historical artifacts which are in the public domain - despite Wiley's copyright claim

    A widespread family of bacterial cell wall assembly proteins

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    Teichoic acids and acidic capsular polysaccharides are major anionic cell wall polymers (APs) in many bacteria, with various critical cell functions, including maintenance of cell shape and structural integrity, charge and cation homeostasis, and multiple aspects of pathogenesis. We have identified the widespread LytR–Cps2A–Psr (LCP) protein family, of previously unknown function, as novel enzymes required for AP synthesis. Structural and biochemical analysis of several LCP proteins suggest that they carry out the final step of transferring APs from their lipid-linked precursor to cell wall peptidoglycan (PG). In Bacillus subtilis, LCP proteins are found in association with the MreB cytoskeleton, suggesting that MreB proteins coordinate the insertion of the major polymers, PG and AP, into the cell wall

    Development of a fish cell culture model to investigate the impact of fish oil replacement on lipid peroxidation

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    Fish oils are rich in omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA), predominantly 20:5n-3 and 22:6n-3, whereas vegetable oils contain abundant C18-PUFA, predominantly 18:3n-3 or 18:2n-6. We hypothesized that replacement of fish oils with vegetable oils would increase the oxidative stability of fish lipids. Here we have used the FHM cell line to test this hypothesis. The FHM cells were readily able to synthesize 20:5n-3 and 24:6n-3 from 18:3n-3 but 22:6n-3 synthesis was negligible. Also, they were readily able to synthesize 20:3n-6 from 18:2n-6 but 20:4n-6 synthesis was negligible. Mitochondrial β-oxidation was greatest for 18:3n-3 and 20:5n-3 and the rates for 16:0, 18:2n-6, 22:6n-3 and 18:1n-9 were significantly lower. Fatty acid incorporation was predominantly into phospholipids (79-97%) with very little incorporation into neutral lipids. Increasing the fatty acid concentration in the growth medium substantially increased the concentrations of 18:3n-3 and 18:2n-6 in the cell phospholipids but this was not the case for 20:5n-3 or 22:6n-3. When they were subjected to oxidative stress, the FHM cells supplemented with either 20:5n-3 or 22:6n-3 (as compared with 18:3n-3 or saturated fatty acids) exhibited significantly higher levels of thiobarbituric reactive substances (TBARS) indicating higher levels of lipid peroxidation. The results are discussed in relation to the effects of fatty acid unsaturation on the oxidative stability of cellular lipids and the implications for sustainable aquaculture

    Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

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    [This corrects the article DOI: 10.1186/s13054-016-1208-6.]

    Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

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    Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

    Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

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    Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

    Ultralight vector dark matter search using data from the KAGRA O3GK run

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    Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM
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