Ecological-economic modelling for the sustainable management of biodiversity

Terrestrial and marine biodiversity provides the basis for both ecosystems functioning and numerous commodities or services that underpin human well-being. From several decades, alarming trends have been reported worldwide for both biodiversity and ecosystem services. Therefore the sustainable management of biodiversity requires a double viewpoint balancing ecological conservation with the welfare of human societies. Understanding the underlying trade-offs, synergies and interactions imposes the development of interdisciplinary researches and methods. In that respect, bio-economic or ecological economic modeling is likely to play a major role. The present paper intends to elicit the key features, strengths and challenges of bio-economic approaches especially in mathematical and computational terms. It first recall the main bio-economic methods, models and decisional instruments used in these types of analyses. Then the paper shows to what extent bio-economic sustainability lies between equilibrium, viability and optimality mathematical frameworks. It ends up by identifying new major challenges among which the operationalization of ecosystem based management, the precautionary principle and the implementation of governance are especially important.     

Determination of the First Excited Singlet State Dipole Moments of Coumarins by the Solvatochromic Method

The electronic absorption and fluorescence spectra of 4-hydroxycoumarin, 7-hydroxycoumarin, 7-methoxycoumarin, 7-hydroxy-4-methylcoumarin, 7-amino-4-methylcoumarin, and 7-diethylamino-4-methylcoumarin were measured at room temperature (298K) in several solvents and their first excited singlet-state dipole moments were determined by the solvatochromic shift method. The excited singlet-state dipole moments of the coumarins were compared with the ground-state values.

     

Simultaneous Determination of Artesunate and Amodiaquine in Fixed-Dose Combination by a RP-HPLC Method with Double UV Detection: Implementation in Interlaboratory Study Involving Seven African National Quality Control Laboratories

The fixed-dose combination artesunate (AS)–amodiaquine (AQ) is one of the most widely used treatments for uncomplicated falciparum malaria. It is currently proposed to the inclusion in the model list of essential medicines of World Health Organization and has been recently prequalified. Until now, no satisfactory method for the simultaneous determination of the two active ingredients had been available. Thus, a reversed phase high performance liquid chromatography for the quantitative determination of AQ and AS was developed and validated. Chromatography was performed using an end-capped octadecylsilyl silica gel column (100?×?4.6?mm, 3?μm) with a binary gradient using aqueous phase containing potassium dihydrogen phosphate (10?mM) and acetonitrile. Taking into consideration the physico-chemical characteristics of the two compounds related to their ionization, the use of a counter ion was necessary to ensure the retention of AQ in a reversed phase system simultaneously to AS. Thus, aqueous mobile phase was adjusted to pH 3.0 and the chosen counter ion was sodium 1-octanesulfonate (100?mM). In these conditions, the retention times were about 4?min for AQ and 10?min for AS with UV detection at 300 and 210?nm, respectively. Method was then validated according to ICH guideline (specificity/linearity/accuracy/precision) and potential interferences with excipients and degradation products were checked. It has also been used for an interlaboratory study involving seven African National Quality Control Laboratories and Afssaps (Agence fran?aise de sécurité sanitaire des produits de santé) laboratory. The results demonstrate that this rapid and simple method can be easily used by official laboratories for routine control, market survey and for the detection of potential substandard medicines which are very frequent in African countries.     

Simultaneous Determination of Artesunate and Amodiaquine in Fixed-Dose Combination by a RP-HPLC Method with Double UV Detection: Implementation in Interlaboratory Study Involving Seven African National Quality Control Laboratories

The fixed-dose combination artesunate (AS)–amodiaquine (AQ) is one of the most widely used treatments for uncomplicated falciparum malaria. It is currently proposed to the inclusion in the model list of essential medicines of World Health Organization and has been recently prequalified. Until now, no satisfactory method for the simultaneous determination of the two active ingredients had been available. Thus, a reversed phase high performance liquid chromatography for the quantitative determination of AQ and AS was developed and validated. Chromatography was performed using an end-capped octadecylsilyl silica gel column (100 × 4.6 mm, 3 μm) with a binary gradient using aqueous phase containing potassium dihydrogen phosphate (10 mM) and acetonitrile. Taking into consideration the physico-chemical characteristics of the two compounds related to their ionization, the use of a counter ion was necessary to ensure the retention of AQ in a reversed phase system simultaneously to AS. Thus, aqueous mobile phase was adjusted to pH 3.0 and the chosen counter ion was sodium 1-octanesulfonate (100 mM). In these conditions, the retention times were about 4 min for AQ and 10 min for AS with UV detection at 300 and 210 nm, respectively. Method was then validated according to ICH guideline (specificity/linearity/accuracy/precision) and potential interferences with excipients and degradation products were checked. It has also been used for an interlaboratory study involving seven African National Quality Control Laboratories and Afssaps (Agence française de sécurité sanitaire des produits de santé) laboratory. The results demonstrate that this rapid and simple method can be easily used by official laboratories for routine control, market survey and for the detection of potential substandard medicines which are very frequent in African countries.

     

Mass Spectrometry Study of Coumarins: Correlation Between Charges of Atoms and Fragmentation Processes

The mass spectrometry of a number of 6-substituted coumarins was studied in the context of correlating fragmentation pathways and electronic charges of atoms performed by AM₁ semiempirical method. The atomic charges of atoms are found to be good predictors of the fragmentation pathways.