Diretor da London School of Economics, Craig Calhoun, é recebido pela FGV/DAPP durante visita institucional

O Diretor da London School of Economics and Political Science (LSE), Craig Calhoun, foi recebido na terça-feira (29) pelo Presidente da Fundação Getulio Vargas, Carlos Ivan Simonsen Leal, durante visita institucional à FGV. Pela manhã, os presidentes das duas instituições tiveram uma reunião com a presença do Secretário-Executivo da LSE, Hugh Martin, do Diretor da DAPP, Marco Aurélio Ruediger, do Diretor da EPGE (Escola Brasileira de Economia e Finanças), Rubens Cysne, da Diretora-Executiva da Editora FGV, Marieta de Moraes Ferreira, e do Prof. Antônio Carlos Porto Gonçalves, também da EPGE. No encontro, foi discutido o maior intercâmbio de alunos entre a LSE e a FGV e em projetos de pesquisa. À tarde, Calhoun realizou uma visita à sede da DAPP, onde participou de uma reunião de apresentação dos métodos de monitoramento e análise de rede desenvolvidos pela DAPP. Participaram da reunião, além do Diretor da DAPP, os pesquisadores Roberta Novis, Amaro Grassi e Pedro Lenhard.

On a refinement of Craig's lattices

Let p be an odd prime. A family of (p - 1)-dimensional over-lattices yielding new record packings for several values of p in the interval [149... 3001] is presented. The result is obtained by modifying Craig's construction and considering conveniently chosen Z-submodules of Q(zeta), where zeta is a primitive pth root of unity. For p >= 59, it is shown that the center density of the (p - 1)-dimensional lattice in the new family is at least twice the center density of the (p - 1)-dimensional Craig lattice. (C) 2010 Elsevier B.V. All rights reserved.

An Extension of Craig's Family of Lattices

Let p be a prime, and let zeta(p) be a primitive p-th root of unity. The lattices in Craig's family are (p - 1)-dimensional and are geometrical representations of the integral Z[zeta(p)]-ideals < 1 - zeta(p)>(i), where i is a positive integer. This lattice construction technique is a powerful one. Indeed, in dimensions p - 1 where 149 <= p <= 3001, Craig's lattices are the densest packings known. Motivated by this, we construct (p - 1)(q - 1)-dimensional lattices from the integral Z[zeta(pq)]-ideals < 1 - zeta(p)>(i) < 1 - zeta(q)>(j), where p and q are distinct primes and i and fare positive integers. In terms of sphere-packing density, the new lattices and those in Craig's family have the same asymptotic behavior. In conclusion, Craig's family is greatly extended while preserving its sphere-packing properties.

Craig Brook; two fishermen bringing in their nets

Archival Collection

A deleterious gene-by-environment interaction imposed by calcium channel blockers in Marfan syndrome.

Calcium channel blockers (CCBs) are prescribed to patients with Marfan syndrome for prophylaxis against aortic aneurysm progression, despite limited evidence for their efficacy and safety in the disorder. Unexpectedly, Marfan mice treated with CCBs show accelerated aneurysm expansion, rupture, and premature lethality. This effect is both extracellular signal-regulated kinase (ERK1/2) dependent and angiotensin-II type 1 receptor (AT1R) dependent. We have identified protein kinase C beta (PKCβ) as a critical mediator of this pathway and demonstrate that the PKCβ inhibitor enzastaurin, and the clinically available anti-hypertensive agent hydralazine, both normalize aortic growth in Marfan mice, in association with reduced PKCβ and ERK1/2 activation. Furthermore, patients with Marfan syndrome and other forms of inherited thoracic aortic aneurysm taking CCBs display increased risk of aortic dissection and need for aortic surgery, compared to patients on other antihypertensive agents.