Adsorption of carbofuran (2,3-dihydro-2,2-dimethyl benzofuran-7-yl carbamate) and fenamiphos (ethyl 4-methylthio-m-tolylisopropyl phosphoramidate) by homoionic montmorillonite - humic acid complex

L'étude de l'adsorption a montré l’influence du cation de saturation des complexes argilo-humiques sur le phénomène d’adsorption des deux pesticides carbofuran et phénamiphos. L’analyse des résultats des différents complexes argilo-humiques (Me-M-HA) a montré que l'adsorption du phénamiphos est plus importante que celle du carbofuran. L'analyse des spectres d’absorption infra-rouge a montré des modifications importantes dans les fréquences de vibration des groupements fonctionnels des deux molécules pesticides au cours de leur adsorption par les complexes argilo-humique. L’analyse par diffraction aux rayons-X des complexes argilo-humiques traité par le carbofuran ou le phénamiphos a montré une augmentation significative de la distance réticulaire d001, indiquant la possibilité de pénétration de ces molécules dans l'espace interlamellaire des complexes saturés par des cations polyvalents

Salinité et pollution par les nitrates des eaux souterraines de la plaine des Triffa

Les eaux souterraines de la plaine des Triffa (Basse Moulouya) deviennent de plus en plus polluées. Les résultats analytiques montrent que la plupart des puits sont chargés en sels et en nitrates, donc impropres à la consommation humaine et peuvent avoir un effet négatif sur les cultures maraîchères de la région. Dans la zone étudiée, des teneurs de 2,32 à 174,70 mg/l de NO3-, de 134 à 3614 mg/l de Cl- et de 103 à 1518 mg/l de Na+ ne sont pas exceptionnelles. Elles dépassent largement les normes fixées par l’OMS et la CEE (50 mg/l pour les NO3 -, de 250 mg/l pour Cl- et de 175 mg/l pour Na+). L’intensification de l’agriculture dans la plaine, notamment dans les périmètres irrigués, l’épandage excessif des engrais, les applications répétées, et à quantités fortes, de fumiers, l’irrigation, les précipitations et la remontée de la nappe dans certaines régions ont engendré une pollution croissante des ressources en eau

Salsolinol Facilitates Glutamatergic Transmission to Dopamine Neurons in the Posterior Ventral Tegmental Area of Rats

Although in vivo evidence indicates that salsolinol, the condensation product of acetaldehyde and dopamine, has properties that may contribute to alcohol abuse, the underlying mechanisms have not been fully elucidated. We have reported previously that salsolinol stimulates dopamine neurons in the posterior ventral tegmental area (p-VTA) partly by reducing inhibitory GABAergic transmission, and that ethanol increases glutamatergic transmission to VTA-dopamine neurons via the activation of dopamine D1 receptors (D1Rs). In this study, we tested the hypothesis that salsolinol stimulates dopamine neurons involving activation of D1Rs. By using whole-cell recordings on p-VTA-dopamine neurons in acute brain slices of rats, we found that salsolinol-induced increase in spike frequency of dopamine neurons was substantially attenuated by DL-2-amino-5-phosphono-valeric acid and 6, 7-dinitroquinoxaline-2, 3-dione, the antagonists of glutamatergic N-Methyl-D-aspartic acid and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors. Moreover, salsolinol increased the amplitude of evoked excitatory postsynaptic currents (EPSCs) and the frequency but not the amplitude of spontaneous EPSCs. Additionally, SKF83566, a D1R antagonist attenuated the salsolinol-induced facilitation of EPSCs and of spontaneous firing of dopamine neurons. Our data reveal that salsolinol enhances glutamatergic transmission onto dopamine neurons via activation of D1Rs at the glutamatergic afferents in dopamine neurons, which contributes to salsolinol's stimulating effect on p-VTA dopamine neurons. This appears to be a novel mechanism which contributes toward rewarding properties of salsolinol

Formalization of the classification pattern: Survey of classification modeling in information systems engineering

Formalization is becoming more common in all stages of the development of information systems, as a better understanding of its benefits emerges. Classification systems are ubiquitous, no more so than in domain modeling. The classification pattern that underlies these systems provides a good case study of the move towards formalization in part because it illustrates some of the barriers to formalization; including the formal complexity of the pattern and the ontological issues surrounding the ‘one and the many’. Powersets are a way of characterizing the (complex) formal structure of the classification pattern and their formalization has been extensively studied in mathematics since Cantor’s work in the late 19th century. One can use this formalization to develop a useful benchmark. There are various communities within Information Systems Engineering (ISE) that are gradually working towards a formalization of the classification pattern. However, for most of these communities this work is incomplete, in that they have not yet arrived at a solution with the expressiveness of the powerset benchmark. This contrasts with the early smooth adoption of powerset by other Information Systems communities to, for example, formalize relations. One way of understanding the varying rates of adoption is recognizing that the different communities have different historical baggage. Many conceptual modeling communities emerged from work done on database design and this creates hurdles to the adoption of the high level of expressiveness of powersets. Another relevant factor is that these communities also often feel, particularly in the case of domain modeling, a responsibility to explain the semantics of whatever formal structures they adopt. This paper aims to make sense of the formalization of the classification pattern in ISE and surveys its history through the literature; starting from the relevant theoretical works of the mathematical literature and gradually shifting focus to the ISE literature. The literature survey follows the evolution of ISE’s understanding of how to formalize the classification pattern. The various proposals are assessed using the classical example of classification; the Linnaean taxonomy formalized using powersets as a benchmark for formal expressiveness. The broad conclusion of the survey is that (1) the ISE community is currently in the early stages of the process of understanding how to formalize the classification pattern, particularly in the requirements for expressiveness exemplified by powersets and (2) that there is an opportunity to intervene and speed up the process of adoption by clarifying this expressiveness. Given the central place that the classification pattern has in domain modeling, this intervention has the potential to lead to significant improvements.The UK Engineering and Physical Sciences Research Council (grant EP/K009923/1)

Materialization and its metaclass implementation

Materialization is a powerful and ubiquitous abstraction pattern for conceptual modeling that relates a class of categories (e.g., models of cars) and a class of more concrete objects (e.g., individual cars). This paper presents materialization as a generic relationship between two classes of objects and describes an abstract implementation of it. The presentation is abstract in that it is not targeted at a specific object system. The target system is supposed to provide: 1) basic object-modeling facilities, supplemented with an explicit metaclass concept and 2) operations for dynamic schema evolution like creation or deletion of a subclass of a given class and modification of the type of an attribute of a class. The presentation is generic in that the semantics of materialization is implemented in a metaclass, which is a template to be instantiated in applications. Application classes are created as instances of the metaclass and they are thereby endowed with structure and behavior consistent with the generic semantics of materialization

Separating Moral Hazard from Adverse Selection in Automobile Insurance: Longitudinal Evidence from France

This paper uses longitudinal data to perform tests of asymmetric information in the French automobile insurance market for the 1995-1997 period.This market is characterized by the presence of a regulated experience-rating scheme (bonusmalus).We demonstrate that the result of the test depends crucially on how the dynamic process between insurance claims and contract choice is modelled.We apply a Granger causality test controlling for the unobservables.We find evidence of moral hazard which we distinguish from adverse selection using a multivariate dynamic panel data model.Experience rating appears to lead high risk policyholders to choose contracts that involve less coverage over time. These policyholders respond to contract changes by increasing their unobservable efforts to reduce claims

Monitoring the Risk of Nitrate Pollution in Mnasra Groundwater Under Field Condition–Morocco

International audienceWater pollution by nitrate has become increasingly a serious problem in Mediterranean countries. Agricultural activities are probably the most significant anthropogenic sources of nitrate contamination in groundwater. Irrigation system is among the causes behind leaching of nitrate from soil surface to groundwater. Gharb plain is the largest agriculture irrigated zone in northwest of Morocco, well known for its intensive agricultural activities. The excessive use of fertilizers and manure under gravity irrigation system, presents a huge risk to groundwater quality especially for sandy-loam soils similar to those of the area. The purpose of the present study was the evaluation of the level of nitrate contamination in groundwater, and the attempt to relate it to the irrigation system adopted in Gharb area. 90 water samples were collected and analyzed by ionic chromatography. Results showed that 86.7% of water samples has exceed the limit of nitrate concentration (50 mg/L) fixed by World Health Organization (WHO). Attempts to focus on the main physical and chemical factors behind the magnitude of contamination are discussed