Time-resolved observations of vibrationally excited NO X 2Π (v′) formed from collisional quenching of NO A 2Σ+ (v = 0) by NO X 2Π: evidence for the participation of the NO a 4Π state

Time resolved observations of the products of NO A 2Σ+ collisional quenching show fast and slow components, consistent with the involvement of a reservoir state (a 4Π) through which a portion of the quenching occurs.

Efficient Assimilation of Crosswell Electromagnetic Data Using an Ensemble-Based History-Matching Framework

Summary An ensemble-based history-matching framework is proposed to enhance the characterization of petroleum reservoirs through the assimilation of crosswell electromagnetic (EM) data. As an advanced technology in reservoir surveillance, crosswell EM tomography can be used to estimate a cross-sectional conductivity map and associated saturation profile at an interwell scale by exploiting the sharp contrast in conductivity between hydrocarbons and saline water. Incorporating this information into reservoir simulation in combination with other available observations is expected to enhance the forecasting capability of reservoir models and to lead to better quantification of uncertainty. The proposed approach applies ensemble-based data-assimilation methods to build a robust and flexible framework in which various sources of available measurements can be integrated. A comparative study evaluates two different implementations of the assimilation of crosswell EM data. The first approach integrates the crosswell EM field components in their original form, which entails forward simulation of the observed EM responses from the simulated reservoir state. In the second approach, formation conductivity is derived from the EM data through inversion and is subsequently assimilated into the reservoir model. An image-oriented distance parameterization of the fluid front assimilates the conductivity field in an efficient and robust manner and overcomes issues with data size, errors, and their correlation. Numerical experiments for different test cases with increasing complexity provide insight into the performance of the two proposed integration schemes. The results demonstrate the efficiency of the developed history-matching workflow and the added value of crosswell EM data in enhancing the reservoir characterization and reliability of dynamic reservoir forecasts.

Population growth potential of rotifers from a high altitude eutrophic waterbody, Madín reservoir (State of Mexico, Mexico): The importance of seasonal sampling

To understand the population growth potential of different species of rotifers in nature, field collections through seasons are essential. We sampled zooplankton (and measured selected physicochemical variables) from the Madín reservoir, a high altitude eutrophic urban waterbody from Mexico, every month for a year. Qualitative analysis of zooplankton revealed 28 rotifer species and four cladoceran crustaceans plus one unidentified copepod. Cephalodella catellina (1400 ind L-1), Horaella thomassoni (550 ind L-1), Conochilus dossuarius (380 ind L-1) and Filinia longiseta (25 ind L-1) had higher peak density than other rotifers. Based on the concentrations of nitrates and phosphates, chlorophyll a levels or different diversity indices (e.g., Carlson, Shannon-Wiener, Pantle and Buck, Ejsmont-Karabin’s TSIRot), the waterbody is eutrophic to hypertrophic, depending on the season. In this waterbody we observed high densities of Aphanothece sp. which is a toxic picocyanobacterium. During the blooms of Aphanothece, we also recorded higher densities of H. thomassoni and C. catellina. Based on the gut contents we found that both these rotifer species feed on Aphanothece in this waterbody. This study thus suggests the potential growth of Horaella, Cephalodella, Conochilus and Filinia in this eutrophic reservoir containing blooms of Aphanothece.

On the Derivation of the GKLS Equation for Weakly Coupled Systems

We consider the reduced dynamics of a small quantum system in interaction with a reservoir when the initial state is factorized. We present a rigorous derivation of a GKLS master equation in the weak-coupling limit for a generic bath, which is not assumed to have a bosonic or fermionic nature, and whose reference state is not necessarily thermal. The crucial assumption is a reservoir state endowed with a mixing property: the n-point connected correlation function of the interaction must be asymptotically bounded by the product of two-point functions (clustering property).