21-(4-Methyl­phenyl­sulfon­yl)-4,7,13,16-tetra­oxa-1,10,21-triaza­bicyclo­[8.8.5]tricosane-19,23-dione: an N-tosyl­ated macrobicyclic dilactam

The macrobicyclic title compound, C23H35N3O8S, contains two tertiary amide bridgehead N atoms and a toluene­sulfonamide N atom in the center of the five-atom bridging strand. The mol­ecule has a central cavity that is defined by the 18-membered ring identified by the N2O4 donor atom set and two 15-membered rings with N3O2 donor atom sets. The toluene­sulfonamide N atom adopts an exo orientation with respect to the central cavity, and the tosyl group is oriented on one side of the aza-bridging strand that connects the bridgehead N atoms

Une synthèse des modèles de représentation des connaissances à base de Graphes Conceptuels et OWL

Nous présentons et comparons deux approches de modélisation, formelles et concrètes, pour représenter et manipuler des connaissances d’un domaine. Le modèle des graphes conceptuels permet de modéliser des connaissances en terme de graphes, basés sur un support. Cette approche de modélisation est intensionnelle, est munie d’une sémantique en logique du premier ordre, et fait l’hypothèse d’un monde fermé pour ses raisonnements. Le langage OWL permet de décrire des ontologies et des faits sur le Web, suivant une approche de modélisation extensionnelle. Il possède une sémantique issue des logiques de descriptions, et fait l’hypothèse d’un monde ouvert pour ses raisonnements

Ecological aspects of Langsdorffia hypogaea (Balanophoraceae) parasitism in the Pantanal wetlands.

Most studies on holoparasitic plants have focused on taxonomic or systematic issues. The objective of this study was to examine the ecological aspects of parasitism of Langsdorffia hypogaea (Balanophoraceae) in the Pantanal wetlands. Individuals of L. hypogaea were dug out by hand and the host trees were identified. Eighty-eight percent of host trees exhibited zoochory dispersal syndrome. Protium heptaphyllum and Cordiera sessilis represented 50% of the sampled trees. Both species are evergreen and are preferentially shade-tolerant species growing under the canopy of other trees. Fecal sample of collared peccaries (Pecari tajacu) had seeds from both the host tree (Protium sp.) and the parasite L. hypogaea. We therefore propose the hypothesis that P. tajacu play a role as a seed disperser and may affect root parasitism

Changes in the structure due to strong winds in forest areas in the Pantanal, Brazil.

The Pantanal climate presents marked seasonality and eventually strong winds occur, especially in the beginning of the rainy season, which may last from September or October until April. A phytosociological study was conducted to evaluate the effects of a strong wind on the composition and structure of two forest formations in Pantanal wetland, a semideciduous forest (19º 15’ 32’’S and 55º 45’ 23.7’’W) and a forested savanna - “cerradão” (19° 17’ 21’’S and 55º 45’ 8.9’’W), with trees with diameter at breast height (DBH) ? 5 cm. After the strong wind, a reduction of 6% of the basal area and volume in the semideciduous forest was observed, mainly due to the uprooting of Xylopia aromatica trees. In the forested savanna, the basal area and volume reduction was even higher; an estimated 10%, representing 69 uprooted trees per hectare, mainly of Copaifera martii trees. In both areas it was observed that the uprooted trees presented an average height and diameter bigger than the trees that remained intact. Usually, the trees that were uprooted presented higher wood density and the species that had broken branches had a lower density

Chen-Ruan cohomology of ADE singularities

We study Ruan's \textit{cohomological crepant resolution conjecture} for orbifolds with transversal ADE singularities. In the $A_n$-case we compute both the Chen-Ruan cohomology ring $H^*_{\rm CR}([Y])$ and the quantum corrected cohomology ring $H^*(Z)(q_1,...,q_n)$. The former is achieved in general, the later up to some additional, technical assumptions. We construct an explicit isomorphism between $H^*_{\rm CR}([Y])$ and $H^*(Z)(-1)$ in the $A_1$-case, verifying Ruan's conjecture. In the $A_n$-case, the family $H^*(Z)(q_1,...,q_n)$ is not defined for $q_1=...=q_n=-1$. This implies that the conjecture should be slightly modified. We propose a new conjecture in the $A_n$-case which we prove in the $A_2$-case by constructing an explicit isomorphism.Comment: This is a short version of my Ph.D. Thesis math.AG/0510528. Version 2: chapters 2,3,4 and 5 has been rewritten using the language of groupoids; a link with the classical McKay correpondence is given. International Journal of Mathematics (to appear

Estrutura e distribuição espacial de Trichilia elegans A. Juss. (Meliaceae) em uma Floresta Semidecídua no Pantanal da Nhecolândia, Mato Grosso do Sul, Brasil.

Trichilia elegans A. Juss. é uma espécie com ampla distribuição, que ocorre desde a Venezuela até o Uruguai, e constitui componente comum no sub-bosque de formações estacionais. Mesmo que os primeiros estudos sobre a flora pantaneira datem de mais de um século, trabalhos voltados para a estrutura e a distribuição espacial de espécies arbóreas ocorrentes na região são ainda raros. Os objetivos do presente estudo foram identificar o padrão de distribuição espacial e a distribuição diamétrica de T. elegans e verificar se existe correlação entre o número de indivíduos jovens e o número de indivíduos adultos em uma floresta semidecídua no Pantanal da Nhecolândia. Para o levantamento, foram amostradas 50 parcelas de 200 m2 cada e inventariados os indivíduos jovens e adultos em cada uma delas. Com o intuito de identificar o padrão de distribuição espacial, foram utilizados o Índice de Morisita (IM) e a razão de variância/média (R). Foram encontrados 218 indivíduos jovens e 78 adultos. Indivíduos jovens e adultos apresentaram distribuição espacial agrupada, estando os jovens (IM = 2,32; R = 5,49) mais agrupados que os adultos (IM = 1,88; R = 2,05). O coeficiente de correlação linear encontrado (r = 0,60) demonstrou que a densidade de indivíduos jovens está altamente correlacionada com a densidade de indivíduos adultos

First results of material charging in the space environment

A satellite experiment, designed to measure potential charging of typical thermal control materials at near geosynchronous altitude, was flown as part of the SCATHA program. Direct observations of charging of typical satellite materials in a natural charging event ( 5 keV) are presented. The results show some features which differ significantly from previous laboratory simulations of the environment