We present results from the first large-scale survey of neutron(n)capture element abundances in planetary nebulae (PNe). This survey was motivated by the fact that a PN may be enriched in n-capture elements if its progenitor star experienced s-process nucleosynthesis during the thermally-pulsing asymptotic giant branch (AGB) phase. We have measured emission from Se and Kr in over 100 PNe, and u...

[1] We investigate the mass dependent isotopic fractionation mechanisms, based on photolytic destruction and reaction with O(D), to explain the N/N and O/O fractionation of stratospheric N2O and reconcile laboratory experiments with atmospheric observations. The Caltech/JPL two-dimensional (2-D) model is utilized for detailed studies of N2O and its isotopologues and isotopomers in the stratosph...

In marine sediments the anaerobic oxidation of methane with sulfate as electron acceptor (AOM) is responsible for the removal of a major part of the greenhouse gas methane. AOM is performed by consortia of anaerobic methane-oxidizing archaea (ANME) and their specific partner bacteria. The physiology of these organisms is poorly understood, which is due to their slow growth with doubling times i...

Abstract Despite international efforts to limit worker exposure coal dust, it continues impact the health of thousands miners across Europe. Airborne dust has been studied improve risk models and its control protect workers. Particle size distribution analyses shows that using spraying systems suppress airborne dusts can reduce particulate matter concentrations coals with higher ash yields prod...

The use of semantics in supervised text classification can improve its effectiveness especially in specific domains. Most state of the art works use concepts as an alternative to words in order to transform the classical bag of words (BOW) into a Bag of concepts (BOC). This transformation is done through conceptualization task. Furthermore, the resulting BOC can be enriched using other related ...

Vertical enrichment profiles of stratospheric 160160180 and 160•80160 (hereafter referred to as 6680 3 and 6860 3 respectively) have been derived from space-based solar occultation spectra recorded at 0.01 cm -I resolution by the ATMOS (Atmospheric Trace MOlecule Spectroscopy) Fouriertransform infrared (FTIR) spectrometer. The observations, made during the Spacelab 3 and ATLAS-l, -2, and -3 shu...

Although many polycyclic aromatic hydrocarbons (PAHs) are known to be biodegraded under aerobic conditions, most contaminated sediments are anaerobic. With recent results demonstrating that some bicyclics and PAHs can be degraded without oxygen, information on specific biodegradation rates and electron acceptor stoichiometry is lacking. A fluidized bed reactor (FBR) enrichment approach was used...

Recently, the concept of rotational mixing has been challenged by some authors (e.g. Hunter et al. 2008). We show that the excess N/H is a multivariate function f(M, age, v sin i, multiplicity, Z). To find a correlation of a multivariate function with some parameter, it is evidently necessary to limit as much as possible the range of the other involved parameters. When this is done, the concept...