Université libre de Bruxelles

About: Université libre de Bruxelles is a education organization based out in Brussels, Belgium. It is known for research contribution in the topics: Population & Breast cancer. The organization has 24974 authors who have published 56969 publications receiving 2084303 citations. The organization is also known as: ULB.

Structure and composition of the Shigella flexneri "needle complex", a part of its type III secreton.

Abstract: Type III secretion systems (TTSSs or secretons), essential virulence determinants of many Gram-negative bacteria, serve to translocate proteins directly from the bacteria into the host cytoplasm Electron microscopy (EM) indicates that the TTSSs of Shigella flexneri are composed of: (1) an external needle; (2) a transmembrane domain; and (3) a cytoplasmic bulb EM analysis of purified and negatively stained parts 1, 2 and a portion of 3 of the TTSS, together termed the "needle complex" (NC), produced an average image at 17 A resolution in which a base, an outer ring and a needle, inserted through the ring into the base, could be discerned This analysis and cryoEM images of NCs indicated that the needle and base contain a central 2-3 nm canal Five major NC components, MxiD, MxiG, MxiJ, MxiH and MxiI, were identified by N-terminal sequencing MxiG and MxiJ are predicted to be inner membrane proteins and presumably form the base MxiD is predicted to be an outer membrane protein and to form the outer ring MxiH and MxiI are small hydrophilic proteins Mutants lacking either of these proteins formed needleless secretons and were unable to secrete Ipa proteins As MxiH was present in NCs in large molar excess, we propose that it is the major needle component MxiI may cap at the external needle tip

Multidisciplinary perspectives on banana (Musa spp.) domestication

Abstract: Original multidisciplinary research hereby clarifies the complex geodomestication pathways that generated the vast range of banana cultivars (cvs). Genetic analyses identify the wild ancestors of modern-day cvs and elucidate several key stages of domestication for different cv groups. Archaeology and linguistics shed light on the historical roles of people in the movement and cultivation of bananas from New Guinea to West Africa during the Holocene. The historical reconstruction of domestication processes is essential for breeding programs seeking to diversify and improve banana cvs for the future.

Fundamental noise limitations to supercontinuum generation in microstructure fiber.

Abstract: Broadband noise on supercontinuum spectra generated in microstructure fiber is shown to lead to amplitude fluctuations as large as 50% for certain input laser pulse parameters. We study this noise using both experimental measurements and numerical simulations with a generalized stochastic nonlinear Schrodinger equation, finding good quantitative agreement over a range of input-pulse energies and chirp values. This noise is shown to arise from nonlinear amplification of two quantum noise inputs: the input-pulse shot noise and the spontaneous Raman scattering down the fiber.

Influence Functions of the Spearman and Kendall Correlation Measures

Abstract: Nonparametric correlation estimators as the Kendall and Spearman correlation are widely used in the applied sciences. They are often said to be robust, in the sense of being resistant to outlying observations. In this paper we formally study their robustness by means of their influence functions and gross-error sensitivities. Since robustness of an estimator often comes at the price of an increased variance, we also compute statistical efficiencies at the normal model. We conclude that both the Spearman and Kendall correlation estimators combine a bounded and smooth influence function with a high efficiency. In a simulation experiment we compare these nonparametric estimators with correlations based on a robust covariance matrix estimator.