1,426 research outputs found

    An investigation into the displacement of Permanent Survey Marks in the Hillcrest area resulting from reactive soils

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    Reactive soils in the Adelaide suburb of Hillcrest (South Australia) have resulted in concrete Permanent Survey Marks (PSMs) being horizontally displaced. This has been identified by different surveys over the past 50 years showing differences in relative measurement between PSMs. It has been assumed that this movement relates directly to the seasonal wetting and drying of reactive soils found in the area. A monitoring project was established, which found that minimal movement occurred within the 10 month study period. The results suggest that any substantial horizontal displacement previously identified is a gradual movement occurring over a number of years rather than seasonally

    Methanol in the sky with diamonds

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    The present of gas phase methanol in dense interstellar molecular clouds was established by radio detection of its rotational emission lines. However, the position, width, and profile of a absorption band near 1470 cm(exp -1) in the IR spectra of many dense molecular clouds strongly suggests that solid methanol is an important component of interstellar ices. In an attempt to better constrain the identification of 1470 cm(exp -1) feature, we began a program to search for other characteristic absorption bands of solid state methanol in the spectra of objects known to produce this band. One such feature is now identified in the spectra of several dense molecular clouds and its position, width, and profile fit well with those of laboratory H2O:CH3OH ices. Thus, the presence of methanol-bearing ices in space is confirmed

    Polyhalogenated heterocyclic compounds. Part 48. Synthesis of perfluoroisopropyl-2,2'-bipyridyl derivatives

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    The synthesis of a highly halogenated 2,2'-bipyridyl system using organometallic methodology is reported

    19F and 13C GIAO-NMR chemical shifts for the identification of perfluoro-quinoline and -isoquinoline derivatives

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    Reaction of perfluoroquinoline 1 and perfluoroisoquinoline 2 with benzylamine gave mono- and di-aminated quinoline and isoquinoline systems, respectively, depending upon the reaction conditions by selective SNAr processes. Optimised model geometries of the aminated derivatives at MP2/6-31G* were in very good agreement with available X-ray crystallographic data and were used to compute 19F and 13C GIAO-NMR shifts. Comparison with observed 19F and 13C NMR shifts give excellent correlations, indicating that 19F and 13C GIAO-NMR computations are powerful tools in structurally identifying polyfunctional, polycyclic perfluoroheteroaromatic compounds and aiding NMR resonance assignment

    Sugar and Sugar Derivatives in Residues Produced from the UV Irradiation of Astrophysical Ice Analogs

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    A large variety and number of organic compounds of prebiotic interest are known to be present in carbonaceous chondrites. Among them, one sugar (dihydroxyacetone) as well as several sugar acids, sugar alcohols, and other sugar derivatives have been reported in the Murchison and Murray meteorites. Their presence, along with amino acids, amphiphiles, and nucleobases strongly suggests that molecules essential to life can form abiotically under astrophysical conditions. This hypothesis is supported by laboratory studies on the formation of complex organic molecules from the ultraviolet (UV) irradiation of simulated astrophysical ice mixtures consisting of H2O, CO, CO2, CH3OH, CH4, NH3, etc., at low temperature. In the past 15 years, these studies have shown that the organic residues recovered at room temperature contain amino acids, amphiphiles, nucleobases, as well as other complex organics. However, no systematic search for the presence of sugars and sugar derivatives in laboratory residues have been reported to date, despite the fact that those compounds are of primary prebiotic significance. Indeed, only small (up to 3 carbon atoms) sugar derivatives including glycerol and glyceric acid have been detected in residues so far

    Observations of lunar tides in the mesosphere and lower thermosphere at Arctic and middle latitudes

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    International audienceMeteor radars have been used to measure the horizontal winds in the mesosphere and lower thermosphere over Castle Eaton (52° N) in the UK and over Esrange (68° N) in Arctic Sweden. We consider a 16-year data set covering the interval 1988?2004 for the UK and a 6-year data set covering the interval 1999?2005 for the Arctic. The signature of the 12.42-h (M2) lunar tide has been identified at both locations. The lunar tide is observed to reach amplitudes as large as 11 ms?1. The Arctic radar has an interferometer and so allows investigation of the vertical structure of the lunar tide. At both locations the tide has maximum amplitudes in winter with a second autumnal maximum. The amplitude is found to increase with height over the 80?100 km height range observed. Vertical wavelengths are very variable, ranging from about 15 km in summer to more than 60 km in winter. Comparisons with the Vial and Forbes, 1994 model reveals generally good agreement, except in the case of the summer vertical wavelengths which are observed to be significantly shorter than predicted

    A Transiting Jupiter Analog

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    Decadal-long radial velocity surveys have recently started to discover analogs to the most influential planet of our solar system, Jupiter. Detecting and characterizing these worlds is expected to shape our understanding of our uniqueness in the cosmos. Despite the great successes of recent transit surveys, Jupiter analogs represent a terra incognita, owing to the strong intrinsic bias of this method against long orbital periods. We here report on the first validated transiting Jupiter analog, Kepler-167e (KOI-490.02), discovered using Kepler archival photometry orbiting the K4-dwarf KIC-3239945. With a radius of (0.91±0.02)(0.91\pm0.02) RJupR_{\mathrm{Jup}}, a low orbital eccentricity (0.06−0.04+0.100.06_{-0.04}^{+0.10}) and an equilibrium temperature of (131±3)(131\pm3) K, Kepler-167e bears many of the basic hallmarks of Jupiter. Kepler-167e is accompanied by three Super-Earths on compact orbits, which we also validate, leaving a large cavity of transiting worlds around the habitable-zone. With two transits and continuous photometric coverage, we are able to uniquely and precisely measure the orbital period of this post snow-line planet (1071.2323±0.00061071.2323\pm0.0006 d), paving the way for follow-up of this K=11.8K=11.8 mag target.Comment: 14 pages, 10 figures. Accepted to ApJ. Posteriors available at https://github.com/CoolWorlds/Kepler-167-Posterior

    Mid-Infrared Study of Samples from Multiple Stones from the Sutters Mill Meteorite

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    The Sutter's Mill meteorite fell in N. California on April 22, 2012 and numerous pieces have been recovered and studied. We present Fourier transform infrared (FTIR) spectra of fragments from several stones of the meteorite. Methods and analysis: Infrared spectra of the samples were recorded with a Nicolet iN10 MX FTIR microscope in the mid-IR range (4000-675/cm; spectral resolution 4/cm). All samples were deposited on a clean glass slide, crushed with a stainless steel roller tool, and placed directly on the focal plane of the microscope. IR spectra were collected by averaging 128 scans. Results: Preliminary IR spectra of the non-fusion crust samples show mineral compositions that are dominated by phyllosilicates, carbonates, or mixtures of both [2]. The carbonates display a dominant, broad band centered at 1433/cm, with additional bands at 2515/cm, 1797/cm, 882/cm, and 715/cm). Features associated with phyllosilicates include a symmetric Si-O stretching mode band centered at 1011/cm and several O-H stretching mode bands. The O-H shows up in two forms (1) a broadband centered at 3415/cm that is probably largely due to adsorbed H2O and (2) a much weaker, narrower feature centered near 3680/cm due to structural -OH. Features observed in the 2985-2855/cm range suggest the presence of aliphatic -CH3 and -CH2- groups. The relative intensities of the bands in this range are somewhat unusual. Typically, the asymmetric aliphatic CH stretching bands are stronger than the symmetric stretching bands, but in this case the reverse is true. This unusual pattern is well matched by the aliphatic features seen in the spectrum of a terrestrial calcite (CaCO3) standard. This observation, and the fact that the strength of the carbonate and aliphatic bands seem to correlate, suggest the organics are associated with the carbonates. Conclusions: IR spectra of samples from the Sutter's Mill meteorite show absorption features associated with carbonates, phyllosilicates, and organics. Both the unusual band profile of the aliphatic C-H stretching mode bands and their correlation with the strength of the carbonate bands suggests the organics and the carbonates are associated in some manner

    Profiling of VEGFs and VEGFRs as Prognostic Factors in Soft Tissue Sarcoma: VEGFR-3 Is an Independent Predictor of Poor Prognosis

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    BACKGROUND: In non-gastrointestinal stromal tumor soft tissue sarcoma (non-GIST STS) optimal treatment is surgery with wide resection margins. Vascular endothelial growth factors (VEGFs) and receptors (VEGFRs) are known to be key players in the initiation of angiogenesis and lymphangiogenesis. This study investigates the prognostic impact of VEGFs and VEGFRs in non-GIST STS with wide and non-wide resection margins. METHODS: Tumor samples from 249 patients with non-GIST STS were obtained and tissue microarrays were constructed for each specimen. Immunohistochemistry was used to evaluate the expressions of VEGF-A, -C and -D and VEGFR-1, -2 and -3. RESULTS: In the univariate analyses, VEGF-A (P=0.040) in the total material, and VEGF-A (P=0.018), VEGF-C (P=0.025) and VEGFR-3 (P=0.027) in the subgroup with wide resection margins, were significant negative prognostic indicators of disease-specific survival (DSS). In the multivariate analysis, high expression of VEGFR-3 (P=0.042, HR=1.907, 95% CI 1.024-3.549) was an independent significant negative prognostic marker for DSS among patients with wide resection margins. CONCLUSION: VEGFR-3 is a strong and independent negative prognostic marker for non-GIST STSs with wide resection margins

    Laser Radar Measurements of Atmospheric Potassium

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    A dye laser capable of transmitting in the near infra red region of the spectrum has been constructed to be used in conjunction with the large Mark II laser system at present in existence at Kingston, Jamaica. Preliminary measurements have been obtained of concentration of atomic potassium in the 70-100 km region of the atmosphere. The data indicates the likelihood of a double peak in the height distribution. The lower peak, which is the" larger, is at a height of about 82 kIn, the upper peak is at a height of 94 kIn. Although an exact value for the scattering cross-section has not been obtained, a reasonable approximation of this parameter yields a value of about 1-15 x 10(exp 11) m(exp -2) for the column density of atomic potassium, which is in agreement with other data
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