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Carbon monoxide (CO) absorption in the sub-damped Lyα absorber at redshift toward the background quasar SDSS J123714.60+064759.5 (J1237+0647) was investigated for the first time in order to search for a possible variation of the proton-to-electron mass ratio, μ, over a cosmological timescale. The observations were performed with the Very Large Telescope/Ultraviolet and Visual Echelle Spectrograph with a signal-to-noise ratio of 40 per 2.5 km s−1 per pixel at ∼5000 Å. Thirteen CO vibrational bands in this absorber are detected: the − (, 0) for , − (0, 0), − (0, 0), and − (0, 0) singlet–singlet bands and the − (5, 0) singlet–triplet band. An updated database including the most precise molecular inputs needed for a μ-variation analysis is presented for rotational levels J = 0–5, consisting of transition wavelengths, oscillator strengths, natural lifetime damping parameters, and sensitivity coefficients to a variation of the proton-to-electron mass ratio. A comprehensive fitting method was used to fit all the CO bands at once and an independent constraint of was derived from CO only. A combined analysis using both molecular hydrogen and CO in the same J1237+0647 absorber returned a final constraint on the relative variation of , which is consistent with no variation over a look-back time of ∼11.4 Gyr. [ABSTRACT FROM AUTHOR]

Two series of p-GaN films grown at different temperatures are obtained by metal organic chemical vapor deposition (MOCVD). And the different variation behaviors of resistivity with growth condition for high- temperature(HT)-grown and low-temperature(LT)-grown p-GaN films are investigated. It is found that the resistivity of HT-grown p-GaN film is nearly unchanged when the NH3 flow rate or reactor pressure increases. However, it decreases largely for LT-grown p-GaN film. These different variations may be attributed to the fact that carbon impurities are easy to incorporate into p-GaN film when the growth temperature is low. It results in a relatively high carbon concentration in LT-grown p-GaN film compared with HT-grown one. Therefore, carbon concentration is more sensitive to the growth condition in these samples, ultimately, leading to the different variation behaviors of resistivity for HT- and LT-grown ones. [ABSTRACT FROM AUTHOR]

The article discusses research finding that African tropical forests are increasing in woody biomass, thereby increasing stocks of tree carbon. Utilizing data that was collected on the continent from 1968 to 2007, the researchers determine at what rate the carbon sink is increasing per hectare of forest and also estimate how much carbon is incorporated into old-growth tropical forests. This increase in biomass could derive from an act of ecological succession following disturbances to forest composition, or it could be indicative of a change in forest equilibrium due to global climatic and atmospheric changes. It is posited that both factors are likely true and working in tandem to change the forests' composition.

Merging carbon-oxygen (CO) white dwarfs are a promising progenitor system for Type Ia supernovae (SNe Ia), but the underlying physics and timing of the detonation are still debated. If an explosion occurs after the secondary star is fully disrupted, the exploding primary will expand into a dense CO medium that may still have a disk-like structure. This interaction will decelerate and distort the ejecta. Here we carry out multidimensional simulations of “tamped” SN Ia models, using both particle and grid-based codes to study the merger and explosion dynamics and a radiative transfer code to calculate synthetic spectra and light curves. We find that post-merger explosions exhibit an hourglass-shaped asymmetry, leading to strong variations in the light curves with viewing angle. The two most important factors affecting the outcome are the scale height of the disk, which depends sensitively on the binary mass ratio, and the total 56Ni yield, which is governed by the central density of the remnant core. The synthetic broadband light curves rise and decline very slowly, and the spectra generally look peculiar, with weak features from intermediate mass elements but relatively strong carbon absorption. We also consider the effects of the viscous evolution of the remnant and show that a longer time delay between merger and explosion probably leads to larger 56Ni yields and more symmetrical remnants. We discuss the relevance of this class of aspherical “tamped” SN Ia for explaining the class of “super-Chandrasekhar” SN Ia. [ABSTRACT FROM AUTHOR]

This work attempts to compare the texture and the adsorption capacity of porous carbons prepared from date palm pits using CO2 and H3PO4 activation. The activation conditions were chosen based on the optimized parameters reported in the literature. The microstructure of the activated carbons was assessed based on nitrogen adsorption, SEM, and FT-IR, while the adsorption capacity was estimated using methylene blue (MB) adsorption. CO2 activation resulted in a microporous carbon with a yield of 44% and a BET surface area of 666m2/g, H3PO4 activation resulted in a mesoporous carbon with a yield of 14.8% and a BET surface area of 725m2/g. The average pore diameter of the activated carbons was estimated to be 1.51 and 2.91nm for CO2 and H3PO4 activation respectively. The equilibrium adsorption isotherms for MB were fitted by the Langmuir and Freundlich models. The monolayer adsorption capacity of CO2 and H3PO4 activated carbons for MB from the Langmuir model were 110 and 345mg/g respectively under the optimized conditions. A highest MB adsorption capacity of 455mg/g was found for the H3PO4 activated carbon with a highest BET surface area. [New Carbon Materials 2012;27(5):344–51]. [ABSTRACT FROM AUTHOR]

El artículo discurre sobre tres defensas de doctorado de la Universidad de la Habana en Cuba, incluyendo una de Pedro Pajón y su estudio de los pontenciales intermoleculares de monóxido de nitrógeno, una de Aliezer Martínez y su estudio de la adsorción de hidrógeno en espumas de carbono, y una de Iván García-Fornaris y su estudio del transporte intergranular en superconductores cerámicos.

The article discusses a case study of a 62-year-old man with rectal cancer, which was tattooed at colonoscopy to localize tumor. Topics include conducting submucosal injection of India ink to the lesion, using methods such as magnetic resonance imaging (MRI) and computed tomography (CT), and the peritoneal deposits which were stained with carbon pigment.

The adsorption of methyl acrylate (MA) on three kinds of activated carbons (AC, Y2, C5) was investigated to evaluate its dependency on initial concentration of the adsorbate, temperature and relative humidity. The experimental results obtained at adsorption equilibrium conditions can be described well by Langmuir-Freundlich equation. The saturated adsorption amount of MA on the AC at 313 K is always the highest among those obtained on the three activated carbons when the initial concentration of MA ranges from 149 X 10-6 to 3 412 X 10-6 in volume ratio. Nevertheless, when the MA concentration is lower than 149 X 10-6, Y2 gives the maximum adsorption amount at equilibrium. The pore properties of activated carbons have much effect on their adsorption capacity. The adsorption capacity of AC and Y2 at different conditions can be well associated with their specific pore structure. A linear correlativity in logarithm between initial concentration of the adsorbate and the 1% breakthrough time at 313 K was obtained over the activated carbons. The results indicate that more than 93% of the adsorption capacity can remain when the adsorption of MA on AC is conducted at the conditions with the relative humidity of 40%. The regeneration of activated carbon and the recovery of the MA can be performed by heating the absorbent to 453 K after adsorption. No change in adsorption capacity can be observed after the adsorption (313 K)-desorption (573 K) is cycled for six times. [ABSTRACT FROM AUTHOR]