11,707 research outputs found

    Fault identification using multidisciplinary techniques at the Mars/Uranus Station antenna sites

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    A fault investigation was performed at the Mars and Uranus antenna sites at the Goldstone Deep Space Communications Complex in the Mojave desert. The Mars/Uranus Station consists of two large-diameter reflector antennas used for communication and control of deep-space probes and other missions. The investigation included interpretation of Landsat thematic mapper scenes, side-looking airborne radar transparencies, and both color-infrared and black-and-white aerial photography. Four photolineaments suggestive of previously undocumented faults were identified. Three generally discrete morphostratigraphic alluvial-fan deposits were also recognized and dated using geomorphic and soil stratigraphic techniques. Fourteen trenches were excavated across the four lineaments; the trenches show that three of the photolineaments coincide with faults. The last displacement of two of the faults occurred between about 12,000 and 35,000 years ago. The third fault was judged to be older than 12,000 years before present (ybp), although uncertainty remains. None of the surface traces of the three faults crosses under existing antennas or structures; however, their potential activity necessitates appropriate seismic retrofit designs and loss-prevention measures to mitigate potential earthquake damage to facilities and structures

    Furuncular myiasis of the foot caused by the tumbu fly, Cordylobia anthropophaga: Report in a Medical Student Returning from a Medical Mission trip to Tanzania.

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    Cutaneous myiasis in humans is a temporary parasitic infestation of the skin by fly larvae or maggots of a variety of Dipteran families. In the United States, autochthonous cases of myiasis are infrequently seen. Most cases of cutaneous myiasis are acquired when traveling to tropical areas of Africa, Central America or South America. This case report involves a 26-year-old male medical student who visited Tanzania on a medical mission trip. Three weeks following his return to the United States he developed a furuncular lesion on the side of the fifth digit on his right foot, which contained the larva of the tumbu fly, Cordylobia anthropophaga

    Unveiling the hard X-ray spectrum from the "burst-only" source SAX J1753.5-2349 in outburst

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    Discovered in 1996 by BeppoSAX during a single type-I burst event, SAX J1753.5-2349 was classified as "burst-only" source. Its persistent emission, either in outburst or in quiescence, had never been observed before October 2008, when SAX J1753.5-2349 was observed for the first time in outburst. Based on INTEGRAL observations,we present here the first high-energy emission study (above 10 keV) of a so-called "burst-only". During the outburst the SAX J1753.5-2349 flux decreased from 10 to 4 mCrab in 18-40 keV, while it was found being in a constant low/hard spectral state. The broad-band (0.3-100 keV) averaged spectrum obtained by combining INTEGRAL/IBIS and Swift/XRT data has been fitted with a thermal Comptonisation model and an electron temperature >24 keV inferred. However, the observed high column density does not allow the detection of the emission from the neutron star surface. Based on the whole set of observations of SAX J1753.5-2349, we are able to provide a rough estimate of the duty cycle of the system and the time-averaged mass-accretion rate. We conclude that the low to very low luminosity of SAX J1753.5-2349 during outburst may make it a good candidate to harbor a very compact binary system.Comment: 5 pages, 3 figures, 2 tables; accepted for publication in MNRAS Letter

    New orbital ephemerides for the dipping source 4U 1323-619: constraining the distance to the source

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    4U 1323-619 is a low mass X-ray binary system that shows type I X-ray bursts and dips. The most accurate estimation of the orbital period is 2.941923(36) hrs and a distance from the source that is lower than 11 kpc has been proposed. We aim to obtain the orbital ephemeris, the orbital period of the system, as well as its derivative to compare the observed luminosity with that predicted by the theory of secular evolution. We took the advantage of about 26 years of X-ray data and grouped the selected observations when close in time. We folded the light curves and used the timing technique, obtaining 12 dip arrival times. We fit the delays of the dip arrival times both with a linear and a quadratic function. We locate 4U 1323-619 within a circular area centred at RA (J2000)= 201.6543\degree and DEC (J2000)= -62.1358\degree with an associated error of 0.0002\degree, and confirm the detection of the IR counterpart already discussed in literature. We estimate an orbital period of P=2.9419156(6) hrs compatible with the estimations that are present in the literature, but with an accuracy ten times higher. We also obtain a constraint on the orbital period derivative for the first time, estimating P˙=(8±13)×1012\dot{P}=(8\pm 13)\times 10^{-12} s/s. Assuming that the companion star is in thermal equilibrium in the lower main sequence, and is a neutron star of 1.4 M_{\odot}, we infer a mass of 0.28±\pm0.03 M_{\odot} for the companion star. Assuming a distance of 10 kpc, we obtained a luminosity of (4.3±\pm0.5)×1036\times 10^{36} erg s1^{-1}, which is not in agreement with what is predicted by the theory of secular evolution. Using a 3D extinction map of the Ks_{s} radiation in our Galaxy, we obtain a distance of 4.20.7+0.8^{+0.8}_{-0.7} kpc at 68\% confidence level. (Abridged)Comment: 10 pages, 8 figures, accepted for publication in Astronomy & Astrophysic
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