Aims. In order to understand the first stages of planet formation, when tiny grains aggregate to form planetesimals, one needs to simultaneously model grain growth, vertical settling and radial migration of dust in protoplanetary disks. In this study, we implement an analytical prescription for grain growth into a 3D two-phase hydrodynamics code to understand its effects on the dust distributio...

An abstract should be given e use the model for the migration of planets introduced in Del Popolo, Yesilyurt & Ercan (2003) to calculate the observed mass and semimajor axis distribution of extra-solar planets. The assumption that the surface density in planetesimals is proportional to that of gas is relaxed, and in order to describe disc evolution we use a method which, using a series of simpl...

14C is an overwhelming background in low-background underground experiments, to the point where the observation of the all-important (pp) neutrinos from the Sun can not be observed in carbon-containing experiments. This paper shows that 14C purity can be improved by four orders of magnitude by a careful selection of the gas field. Two large reduction factors are at work: the low chemical affini...

The dynamics of planetesimals and planetary cores may be strongly influenced by density perturbations due to magnetorotational turbulence in their natal protoplanetary gas disks. Using the local shearing box approximation, we perform numerical simulations of planetesimals moving as massless particles in a turbulent, magnetized, unstratified gas disk. Our fiducial disk model has turbulent accret...

We analyse a high-resolution, fully cosmological, hydrodynamical disc galaxy simulation, to study the source of the double-exponential light profiles seen in many stellar discs, and the effects of stellar radial migration upon the spatio-temporal evolution of both the disc age and metallicity distributions. We find a “break” in the pure exponential stellar surface brightness profile, and trace ...

We develop a relationship between the sulfate-methane transition (SMT) and average gas hydrate saturation (AGHS) for systems dominated by methane migration from deeper sources. The relationship is explained by a onedimensional numerical model that simulates gas hydrate accumulation in marine sediments. Higher methane fluxes result in shallow SMT depths and high AGHS, while lower methane fluxes ...

The low enthalpy program developped in the Paris Basin provides the opportunity for studying the gas geochemistry of the calcareous aquifer of the Dogger. Hydrocarbons and C02 are mainly biogenic, He displays high concentrations. He, Ar and N2 have multiple origins (radioactive decay, atmospheric migration, biochemical processes). The distribution of the gases in the zones of the basin varies i...

A 52-year-old man developed severe vision loss in the right eye due to a large retinal detachment. Vitrectomy was performed in that eye, with 15% C3F8 perfluoropropane gas injected into the posterior chamber.1 He transiently regained hand-motion acuity. Posterior chamber paracentesis was performed for elevated intraocular pressure; endophthalmitis was treated with intraocular antibiotics. After...

The debate surrounding the safety of shale gas development in the Appalachian Basin has generated increased awareness of drinking water quality in rural communities. Concerns include the potential for migration of stray gas, metal-rich formation brines, and hydraulic fracturing and/or flowback fluids to drinking water aquifers. A critical question common to these environmental risks is the hydr...

Public concerns over potential environmental contamination associated with oil and gas well drilling and fracturing in the Wattenberg field in northeast Colorado are increasing. One of the issues of concern is the migration of oil, gas, or produced water to a groundwater aquifer resulting in contamination of drinking water. Since methane is the major component of natural gas and it can be disso...