Analytic elastic constants in molecular calculations: Finite strain, non-affine displacements, and many-body interatomic potentials

Elastic constants are among the most fundamental and important properties of solid materials, which is why they are routinely characterized in both experiments and simulations. While conceptually simple, the treatment of elastic constants is complicated by two factors not yet having been concurrently discussed: finite-strain and non-affine, internal displacements. Here, we revisit the theory behind zero-temperature, finite-strain elastic constants and extend it to explicitly consider non-affine displacements. We further present analytical expressions for second-order derivatives of the potential energy for two-body and generic many-body interatomic potentials, such as cluster and empirical bond-order potentials. Specifically, we revisit the elastic constants of silicon, silicon carbide and silicon dioxide under hydrostatic compression and dilatation. Based on existing and new results, we outline the effect of multiaxial stress states as opposed to volumetric deformation on the limits of stability of their crystalline lattices.Comment: 22 pages, 7 figure

Temporal patterns of emergence, calling behaviour and oviposition period of the maize stem borer, Busseola fusca (Fuller) (Lepidoptera : Noctuidae)

Sexual behaviour in most of the noctuid Lepidoptera follows a diel periodicity and is limited to a precise period of either the day or the night. The periodicity and the maturation periods are specific as well as the onset of oviposition behaviour. The knowledge of these traits of biology is an essential prerequisite for all the studies in chemical ecology. The periodicity of adult emergence, calling behaviour and oviposition of Busseola fusca (Fuller) was studied under laboratory conditions. Most males emerged before onset of the scotophase whereas most females did so one hour later. The virgin females started to exhibit calling behaviour few hours after emergence and there is no sexual maturation time. The calling behaviour starts the fourth hour after the onset of the scotophase but is lightly delayed for females having emerged the same night as compared to older females. Sexual and oviposition behaviours occur during the dark period. Oviposition started the first night after the mating night, peaked during the second night and then gradually decreased until the fifth night. The first night of oviposition, females laid eggs during the first three hours and after the 5(th) hour of the scotophase with a maximum during the 8(th) and 9(th) hour. During the second night, oviposition peaked during the second hour and tended to decrease thereafter

Temporal patterns of emergence, calling behaviour and oviposition period of the maize stem borer, Busseola fusca (Fuller) (Lepidoptera: Noctuidae). Ann. Société Entomologique Fr

Abstract. Sexual behaviour in most of the noctuid Lepidoptera follows a diel periodicity and is limited to a precise period of either the day or the night. The periodicity and the maturation periods are specifi c as well as the onset of oviposition behaviour. The knowledge of these traits of biology is an essential prerequisite for all the studies in chemical ecology. The periodicity of adult emergence, calling behaviour and oviposition of Busseola fusca (Fuller) was studied under laboratory conditions. Most males emerged before onset of the scotophase whereas most females did so one hour later. The virgin females started to exhibit calling behaviour few hours after emergence and there is no sexual maturation time. The calling behaviour starts the fourth hour after the onset of the scotophase but is lightly delayed for females having emerged the same night as compared to older females. Sexual and oviposition behaviours occur during the dark period. Oviposition started the fi rst night after the mating night, peaked during the second night and then gradually decreased until the fi fth night. The fi rst night of oviposition, females laid eggs during the fi rst three hours and after the 5 th hour of the scotophase with a maximum during the 8 th and 9 th hour. During the second night, oviposition peaked during the second hour and tended to decrease thereafter. Résumé. Chronologie de l'émergence, du comportement d'appel et de l'oviposition chez la mineuse du maïs Busseola fusca (Fuller) (Lepidoptera : Noctuidae). Le comportement sexuel de la plupart des lépidoptères Noctuidae est cyclique et limité à une période bien précise du jour ou de la nuit. Les rythmes et les délais de maturation sexuelle sont propres à chaque espèce. L'initiation du comportement de ponte est aussi une des composantes de l'espèce. La connaissance de ces points de biologie est un préalable indispensable à toutes études d'écologie chimique qui traitent de la reconnaissance du partenaire sexuel et de la plante-hôte. Les périodes d'émergence, du comportement d'appel et de ponte de Busseola fusca (Fuller) ont été étudiées dans des conditions de laboratoire. La plupart des mâles émergent avant le début de nuit et les femelles lors des premières heures. Le comportement d'appel des femelles vierges débute quelques heures après l'émergence et il n'y pas chez B. fusca de délai de maturation sexuelle. La période d'appel commence quatre heures après le début de nuit, et est un peu plus tardive pour les femelles qui viennent d'émerger. L'insecte présente une activité nocturne tant pour l'accouplement que pour la ponte. L'oviposition débute la nuit qui suit celle de l'accouplement et la quantité d'oeufs déposés augmente la deuxième nuit de ponte pour ensuite décroître progressivement jusqu'à la cinquième nuit. La ponte se répartit sur toute la durée de la scotophase avec deux pics : l'un se situe en début de nuit et l'autre dans la seconde moitié de la scotophase

Using biomarkers in an evolutionary context: Lessons from the analysis of biological responses of oligochaete annelids to metal exposure

International audienceAnthropogenic activities may lead to the accumulation of inorganic and organic compounds in topsoils. Biota living in close contact with contaminated soils may experience stress at different levels of biological organization throughout the continuum from molecular to community level. Biological responses observed at the individual or infra-individual level of biological organization led to the development of biomarkers. The development of biomarkers consists often in evidencing biological modifications following a contaminant stress in laboratory conditions, using naïve organisms and it is sometime proposed to use the biological state of individuals from sentinel species collected in the field to evaluate the level of environmental exposure. However, considering the possibility of local adaptation following long-term exposure, organisms response sampled in the field may substantially differ from laboratory specimens. In this review, we discuss this point focusing on the definition and validity of molecular biomarkers of metal pollution using earthworms of the Lumbricidae family. © 2013 Elsevier Ltd. All rights reserved

Identification des constituants de la pheromone sexuelle de Pareuchaete pseudoinsulata Rego Barros (Lepidoptera, Arctiidae)

National audienc

Impact of a zinc processing factory on surrounding surficial soil contamination

International audienceZn smelting plants located at Auby (Northern France) have strongly polluted the surroundings through dust emissions, storage of ores and slag without strong environmental concerns. Although highly contaminated surficial soils have been removed in the private and public gardens to safeguard health of the inhabitants, one small public area, called the Peru Park, has not been treated because of the presence of peculiar calamine grasslands. Our investigations in the soils of this park clearly evidenced a very strong contamination by several metals with concentrations up to 21,000 mg kg−1 for Zn, 3500 mg kg−1 for Pb and 160 mg kg−1 for Cd. Additionally, the mobility of these metals is important in soils and increases with the pollution level. In the pore waters of strongly polluted zones, our findings are more contrasted with high concentrations of dissolved Zn (3.6–32 mg L−1) and to a lesser extent Cd (0.02–0.25 mg L−1), whereas dissolved Pb remains at low concentrations (0.0001–0.021 mg L−1) and, according to calculations, is quite exclusively bound to humic substances. Finally, this study obviously underlines that this severe pollution and the high mobility of Zn and Cd could strongly impact the surficial aquifer and the trophic chain present in this area

Temporal patterns of emergence, calling behaviour and oviposition period of the maize stem borer, Busseola fusca (Fuller) (Lepidoptera : Noctuidae)

Sexual behaviour in most of the noctuid Lepidoptera follows a diel periodicity and is limited to a precise period of either the day or the night. The periodicity and the maturation periods are specific as well as the onset of oviposition behaviour. The knowledge of these traits of biology is an essential prerequisite for all the studies in chemical ecology. The periodicity of adult emergence, calling behaviour and oviposition of Busseola fusca (Fuller) was studied under laboratory conditions. Most males emerged before onset of the scotophase whereas most females did so one hour later. The virgin females started to exhibit calling behaviour few hours after emergence and there is no sexual maturation time. The calling behaviour starts the fourth hour after the onset of the scotophase but is lightly delayed for females having emerged the same night as compared to older females. Sexual and oviposition behaviours occur during the dark period. Oviposition started the first night after the mating night, peaked during the second night and then gradually decreased until the fifth night. The first night of oviposition, females laid eggs during the first three hours and after the 5(th) hour of the scotophase with a maximum during the 8(th) and 9(th) hour. During the second night, oviposition peaked during the second hour and tended to decrease thereafter