57 research outputs found

    Scientific goals for the observation of Venus by VIRTIS on ESA/Venus Express mission

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    The Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on board the ESA/Venus Express mission has technical specifications well suited for many science objectives of Venus exploration. VIRTIS will both comprehensively explore a plethora of atmospheric properties and processes and map optical properties of the surface through its three channels, VIRTIS-M-vis (imaging spectrometer in the 0.3–1 micron range), VIRTIS-M-IR (imaging spectrometer in the 1–5 micron range) and VIRTIS-H (aperture highresolution spectrometer in the 2–5 micron range). The atmospheric composition below the clouds will be repeatedly measured in the night side infrared windows over a wide range of latitudes and longitudes, thereby providing information on Venus’s chemical cycles. In particular, CO, H2O, OCS and SO2 can be studied. The cloud structure will be repeatedly mapped from the brightness contrasts in the near-infrared night side windows, providing new insights into Venusian meteorology. The global circulation and local dynamics of Venus will be extensively studied from infrared and visible spectral images. The thermal structure above the clouds will be retrieved in the night side using the 4.3 micron fundamental band of CO2. The surface of Venus is detectable in the short-wave infrared windows on the night side at 1.01, 1.10 and 1.18 micron, providing constraints on surface properties and the extent of active volcanism. Many more tentative studies are also possible, such as lightning detection, the composition of volcanic emissions, and mesospheric wave propagation

    Kinetics of Thermal Decomposition of Particulate Samples of MgCO3: Experiments and Models

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    In this work, we study the kinetics of thermal decomposition of MgCO3 in the form of particles of known size. In the experiments, the material is heated to a known temperature in a vacuum oven, and it is characterized, both before and after heating, by infrared spectroscopy and gravimetry. The agreement between the results of the two techniques is excellent. These results are rationalized by means of a model based on Languir's law, and the comparison with the experiments allows us to estimate the activation energy of the process. The reabsorption of atmospheric water by the oxide is shown spectroscopically, finding that is strongly influenced by the temperature of the process

    Spectral Evidence of Aqueous Activity in Two Putative Martian Paleolakes

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    CRISM observations of putative paleolakes in Cankuzo and Luqa craters exhibit spectral features consistent with the activity of water. The spatial distributions suggest different formation scenarios for each site. In Cankuzo the distribution suggests postimpact alteration whereas in Luqa there are hints of possible formation of a layer of phyllosilicate materials

    Switch to maraviroc with darunavir/r, both QD, in patients with suppressed HIV-1 was well tolerated but virologically inferior to standard antiretroviral therapy: 48-Week results of a randomized trial

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    Objectives Primary study outcome was absence of treatment failure (virological failure, VF, or treatment interruption) per protocol at week 48. Methods Patients on 3-drug ART with stable HIV-1 RNA <50 copies/mL and CCR5-tropic virus were randomized 1:1 to maraviroc with darunavir/ritonavir qd (study arm) or continue current ART (continuation arm).Results In June 2015, 115 patients were evaluable for the primary outcome (56 study, 59 continuation arm). The study was discontinued due to excess of VF in the study arm (7 cases, 12.5%, vs 0 in the continuation arm, p = 0.005). The proportion free of treatment failure was 73.2% in the study and 59.3% in the continuation arm. Two participants in the study and 10 in the continuation arm discontinued therapy due to adverse events (p = 0.030). At VF, no emergent drug resistance was detected. Co-receptor tropism switched to non-R5 in one patient. Patients with VF reported lower adherence and had lower plasma drug levels. Femoral bone mineral density was significantly improved in the study arm. Conclusion Switching to maraviroc with darunavir/ritonavir qd in virologically suppressed patients was associated with improved tolerability but was virologically inferior to 3-drug therap

    Switch to maraviroc with darunavir/r, both QD, in patients with suppressed HIV-1 was well tolerated but virologically inferior to standard antiretroviral therapy: 48-Week results of a randomized trial

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    Objectives: Primary study outcome was absence of treatment failure (virological failure, VF, or treatment interruption) per protocol at week 48. Methods: Patients on 3-drug ART with stable HIV-1 RNA <50 copies/mL and CCR5-tropic virus were randomized 1:1 to maraviroc with darunavir/ritonavir qd (study arm) or continue current ART (continuation arm). Results: In June 2015, 115 patients were evaluable for the primary outcome (56 study, 59 continuation arm). The study was discontinued due to excess of VF in the study arm (7 cases, 12.5%, vs 0 in the continuation arm, p = 0.005). The proportion free of treatment failure was 73.2% in the study and 59.3% in the continuation arm. Two participants in the study and 10 in the continuation arm discontinued therapy due to adverse events (p = 0.030). At VF, no emergent drug resistance was detected. Co-receptor tropism switched to non-R5 in one patient. Patients with VF reported lower adherence and had lower plasma drug levels. Femoral bone mineral density was significantly improved in the study arm. Conclusion: Switching to maraviroc with darunavir/ritonavir qd in virologically suppressed patients was associated with improved tolerability but was virologically inferior to 3-drug therapy

    Main Belt Comets and other “Interlopers” in the Solar System

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    According to traditional ideas about the formation of the Solar System starting from a protoplanetary disk of gas and dust, a well-defined distribution of planets and minor bodies is expected: (a) volatile-poor rocky bodies (terrestrial planets and asteroids) in the inner part of the Solar System and (b) volatile-rich objects (gaseous giant planets, comets, Centaurs, and trans-Neptunian objects) in the outer part. All these bodies are expected to orbit near a plane (the ecliptic) coinciding with that of the protoplanetary disk. However, in the modern Solar System many bodies are present that do not respect this simplistic expectation. First of all, there are the so-called Main Belt Comets, apparently asteroidal objects that show an activity similar to that of comets. In addition, there is an object (and several others very probably exist), which, despite its S-type spectrum characteristic of rocky bodies, is found on a cometary orbit. Finally, there are many asteroids on very inclined orbits with respect to the ecliptic. These very interesting groups of objects, which, according to the traditional point of view, could be collectively seen as some sort of “interlopers” of the Solar System, will be discussed in this review, which offers descriptions of their properties and their likely origin. In this respect, the possibility is discussed that many active asteroids (such as those belonging to the Taurid Complex) are the result of the fragmentation of large comets that occurred in the relatively recent past

    Amorphous carbon around carbon stars

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