Complete Singular Collineations and Quadrics

We construct wonderful compactifications of the spaces of linear maps and symmetric linear maps of a given rank as blowups of secant varieties of Segre and Veronese varieties. Furthermore, we investigate their birational geometry and their relations with some spaces of degree two stable maps

Product Differentiation Costs and Global Competition

The growing competitive intensity on the markets determines the emergence of competition costs that are expressed at a corporate level and have implicit repercussions for the supply system. This type of costs makes it possible to identify a close link between competition costs and supply differentiation costs. Classification by competitive intensity presupposes that the analysis performed identifies the classification of company costs as the discriminating element, in terms of the competitive pressure of the context in which the firm operates. The emergence of competition costs is linked to an attempt to squeeze them as an aspect of vertical, or more specifically, horizontal cooperation strategies.Product Differentiation; Differentiation Costs; Over-Supply; Global Competition; Marketing; Market-Driven Management; Global Corporations; Global Markets DOI:http://dx.doi.org/10.4468/2005.1.06garbelli

Efeito de herbicidas sobre a taxa de transporte de elétrons e o acúmulo de matéria seca em tomateiro.

Objetivou-se com este trabalho avaliar o efeito dos herbicidas metribuzin e carfentrazone sobre a taxa de transporte de elétrons (ETR) do fotossistema II (FSII) e o acúmulo de matéria seca em tomateiro.CD-ROM. Suplemento. Trabalho apresentado no 51. Congresso Brasileiro de Olericultura, Viçosa, MG

Potential allelochemicals of the invasive species Carduus nutans L. and C. acanthoides.

The thistles Carduus nutants L. and C. acanthoides L. have both been implicated as allelopathic species. These Eurasian native plants are invasive in the U.S. and other parts of the world, competing well with many native species. Bioassay-guided isolation of phytotoxins from shoots and roots of this plant revealed that a chemical found in the roots, aplotaxene (heptadeca-1,8,11,14-tetrane), to be the most likely candidate as an allelochemical. Contrary to the published work of others, we found that this compound to be moderately phytotoxic. It was also found in relatively large amounts in the roots of both Carduus species, and we found the compound to be exuded by the roots into the soil

Avaliação do teor de sorgoleone presente em extratos de raízes de cultivares de sorgo por cromatografia líquida de alta eficiência (HPLC).

Considerando a importância da cultura do sorgo no Brasil e sua conhecida atividade alelopática, este estudo objetivou avaliar as concentrações de sorgoleone presentes em raízes de cultivares de sorgo. O experimento foi realizado na Embrapa Meio Ambiente, em Jaguariúna-SP. O delineamento experimental utilizado foi de blocos inteiramente casualizados, com 3 repetições. As cultivares de sorgo estudadas foram BRS 716, BRS 511, AG 1080, CR 1339, CR 1350, CR 1108, CR 1113, CR 1342 e CR 1010, pertencentes a diferentes empresas e tipos de sorgo (granífero, sacarino e biomassa). As concentrações de sorgoleone nos exsudados das raízes de sorgo foramquantificadas utilizando-se um aparelho de Cromatografia Líquida de Alta Eficiência (HPLC). Os resultados do teste de probabilidade mostraram que as quantidades de sorgoleone encontradas nas raízes de sorgo variaram em função da cultivar estudada. A produção de sorgoleone variou de 32,64 mg g-1 de extrato, na cultivar de sorgo biomassa BRS 716, até 615,31 mg g-1, na cultivar de sorgo biomassa CR1342. Assim, concluiu-se que a concentração de sorgoleone nas raízes de sorgo varia conforme a cultivar.bitstream/item/159489/1/bol-145-2.pd

Complete symplectic quadrics and Kontsevich spaces of conics in Lagrangian Grassmannians

A wonderful compactification of an orbit under the action of a semi-simple and simply connected group is a smooth projective variety containing the orbit as a dense open subset, and where the added boundary divisor is simple normal crossing. We construct the wonderful compactification of the space of symmetric and symplectic matrices, and investigate its geometry. As an application, we describe the birational geometry of the Kontsevich spaces parametrizing conics in Lagrangian Grassmannians