University of the Littoral Opal Coast

About: University of the Littoral Opal Coast is a education organization based out in Dunkirk, France. It is known for research contribution in the topics: Catalysis & Dielectric. The organization has 1242 authors who have published 2383 publications receiving 46230 citations. The organization is also known as: ULCO.

Microbial community production, respiration, and structure of the microbial food web of an ecosystem in the northeastern Atlantic Ocean

Abstract: increased from winter (101 ± 24 mmol O2 m 2 d 1 ) to spring (153 ± 27 mmol O2 m 2 d 1 ) and then decreased from spring to late summer (44 ± 18 mmol O2 m 2 d 1 ). DCR rates increased from winter (47 ± 18 mmol O2 m 2 d 1 ) to spring (97 ± 7 mmol O2 m 2 d 1 ) and then decreased from spring to late summer (50 ± 7 mmol O2 m 2 d 1 ). The onset of stratification depended on latitude as well as on the presence of mesoscale structures (eddies), and this largely contributed to the variability of GCP. The trophic status of the POMME area was defined as net autotrophic, with a mean annual net community production rate of +38 ± 18 mmol O2 m 2 d 1 , exhibiting a seasonal variation from +2 ± 20 mmol O2 m 2 d 1 to +57 ± 20 mmol O2 m 2 d 1 . This study highlights that small organisms (picoautotrophs, nanoautotrophs, and bacteria) are the main organisms contributing to biological fluxes throughout the year and that episodic blooms of microphytoplankton are related to mesoscale structures.

Fitness Landscapes and Performance of Meta-Heuristics

Abstract: We perform a statistical analysis of the structure of the search space of some planar, euclidian instances of the traveling salesman problem. We want to depict this structure from the point of view of iterated local search algorithms. The objective is two-fold: understanding the experimentally known good performance of metaheuristics on the TSP and other combinatorial optimization problems; designing new techniques to search the space more efficiently. This work actually led us to design a hybrid genetic algorithm that competes rather well with other local search heuristics for the TSP, notably Junger et al.’s version of ILK. This work also opens promising horizons to the study of other combinatorial optimization problems such as the quadratic assignment problem.

Host-Guest Modulation of the Micellization of a Tetrathiafulvalene-Functionalized Poly(N-isopropylacrylamide)

Abstract: The aqueous solution properties of amphiphilic tetrathiafulvalene (TTF) end-functionalized poly(N-isopropylacrylamide) (PNIPAM) derivative 1 have been studied. Fluorescence spectroscopy, dynamic light scattering (DLS) and differential scanning calorimetry (Nano-DSC) were used to monitor the temperature-induced micellization and showed that 1 underwent two successive phase transitions corresponding to unimer-to-micelle and lower critical solution temperature (LCST) transitions, respectively. We have investigated the complexation properties of the TTF unit toward cyclobis(paraquat-p-phenylene) (CBPQT4+) or the randomly methylated β-cyclodextrin (RAMEB) to manipulate the amphiphilicity of 1 and to control the unimer-to-micelle phase transition by forming pseudorotaxane-like architectures. For the RAMEB complex with 1, the addition of a competitive guest such as 1-adamantanol resulted in the restoration of amphiphilicity of polymer 1 and consequently the reformation of micelles.

Schreier split epimorphisms between monoids

Abstract: We explore some properties of Schreier split epimorphisms between monoids, which correspond to monoid actions. In particular, we prove that the split short five lemma holds for monoids, when it is restricted to Schreier split epimorphisms, and that any Schreier reflexive relation is transitive, partially recovering in monoids a classical property of Mal’tsev varieties.