Mission d´appui en acridologie et en ecologie operationnelle auprès du NMA/EMBRAPA - Campinas - Bresil: du 26 mars au 5 avril 1990.

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Introdução ao estudo dos surtos do gafanhoto praga: Rhammatocerus pictus (Bruner, 1900) (Orthoptera, Acrididae, gomphocerinae) em Mato Grosso (Brasil).

Identidade da praga; origem provavel dos surtos; Organização atual de controle; Ensaio de avaliação quantitativa; Perspectivas de evolução da situação acridiana e recomendações.bitstream/item/142800/1/ID-51252.pd

Maturation sexuelle et fonctionnement ovarien de Rhammatocerus schistocercoides (Rehn, 1906) (Orthoptères, Acrididae, Gomphocerinae), acridien ravageur de l´état du Mato Grosso (Brésil).

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Superconducting diamagnetic fluctuations in ropes of carbon nanotubes

We report low-temperature magnetisation measurements on a large number of purified ropes of single wall carbon nanotubes. In spite of a large superparamagnetic contribution due to the small ferromagnetic catalytical particles still present in the sample, at low temperature ($T < 0.5K$) and low magnetic field ($H < 80 Oe$), a diamagnetic signal is detectable. This low temperature diamagnetism can be interpreted as the Meissner effect in ropes of carbon nanotubes which have previously been shown to exhibit superconductivity from transport measurements.Comment: 10 pages 3 figure

Introduction a l'etude des pullulations du criquet ravageur Rhammatocerus pictus (Bruner, 1900) (Orthoptera, Acrididae, Gomphocerinae) au Mato Grosso (Bresil).

Identite du ravageur; Origine probable des pullulations; Organisation actuelle de la lutte; Essais d' evaluation quantitative; Perspectives d' evolution de la situation acridienne et recommandations; Conclusions; Annexe: calendrier de mission.bitstream/item/180112/1/FL-1156.pdfMission du 9 au 16 octobre 1984

Notes monographiques preliminares sur Eutropidacris collaris (Stoll, 1813) (Orthoptera, Romaleidae, Romaleinae) au Bresil.

Identite taxonomique; Distribution geographique et importance economique; Caracteres bio-ecologiques; Perspectives de controle des pullulations; Conclusion: Les recherches a entreprendre.bitstream/item/180113/1/FL-1200.pdfMission du 5 octobre au 3 novembre 1984

La fièvre aphteuse

La fièvre aphteuse, l’une des maladies les plus contagieuses et qui frappe surtout les bovins, mais aussi les porcins, les ovins et les caprins, peut avoir des conséquences dévastatrices sur les agriculteurs et l’économie agricole. Par l’adoption d’une approche novatrice, cet ouvrage explore cette maladie, en apportant des faits concrets et exhaustifs. Chaque chapitre se penche sur une perspective différente, en faisant part des témoignages réfléchis d’agriculteurs et de vétérinaires, d’économistes et de journalistes, tant dans les pays en développement que dans les pays industrialisés

A quantum analogue of the dihedral action on Grassmannians

In recent work, Launois and Lenagan have shown how to construct a cocycle twisting of the quantum Grassmannian and an isomorphism of the twisted and untwisted algebras that sends a given quantum minor to the minor whose index set is permuted according to the $n$-cycle $c=(1, 2, ..., n)$, up to a power of $q$. This twisting is needed because $c$ does not naturally induce an automorphism of the quantum Grassmannian, as it does classically and semi-classically. We extend this construction to give a quantum analogue of the action on the Grassmannian of the dihedral subgroup of $S_{n}$ generated by $c$ and $w_{0}$, the longest element, and this analogue takes the form of a groupoid. We show that there is an induced action of this subgroup on the torus-invariant prime ideals of the quantum Grassmannian and also show that this subgroup acts on the totally nonnegative and totally positive Grassmannians. Then we see that this dihedral subgroup action exists classically, semi-classically (by Poisson automorphisms and anti-automorphisms, a result of Yakimov) and in the quantum and nonnegative settings.Comment: 22 pages, 2 figures. Version 2: substantially revised organisation and presentatio

Theory of Distinct Crystal Structures of Polymerized Fullerides AC60, A=K, Rb, Cs: the Specific Role of Alkalis

The polymer phases of AC60 form distinct crystal structures characterized by the mutual orientations of the (C60-)n chains. We show that the direct electric quadrupole interaction between chains always favors the orthorhombic structure Pmnn with alternating chain orientations. However the specific quadrupolar polarizability of the alkali metal ions leads to an indirect interchain coupling which favors the monoclinic structure I2/m with equal chain orientations. The competition between direct and indirect interactions explains the structural difference between KC60 and RbC60, CsC60.Comment: 4 pages, 2 figures, 1 tabl

Mission conjointe NMA/PRIFAS d´étude et de prospective dans Le Sudeste du Bresil, du 27 octobre au 10 novembre 1990.

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