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.

Regulation of Maternal Thyroid during Pregnancy

Abstract: A prospective study was undertaken in 606 healthy women during pregnancy to evaluate the changes occurring in maternal thyroid economy as a result of 1) the increased thyroid hormone-binding capacity of serum, 2) the effects of increased levels of hCG on TSH and on the thyroid, and 3) a marginally low iodine intake in the population (50-75 micrograms/day). Four main features were observed. First, thyroidal activity adjusted to the marked increase in serum T4-binding globulin: pregnancy was accompanied by an overall reduction in the T4/T4-binding globulin ratio, with lower free T4 and T3 levels, although in most cases free hormone levels remained within the normal range. The adjustment of thyroidal output of T4 and T3 did not occur similarly in all subjects. In approximately one third of the women, there was relative hypothyroxinemia, higher T3/T4 ratios (presumably indicating preferential T3 secretion), and higher, although normal, serum TSH concentrations. Second, high hCG levels were associated with thyroid stimulation, both functionally (lower serum TSH) and anatomically (increased thyroid size). The data are consistent with a TSH-like effect of hCG on the thyroid. Hence, regulation of the maternal thyroid is complex, resulting from both elevated hCG (mainly in the first half of gestation) and increasing TSH (mainly in the second half of gestation). Third, a significant increase in serum thyroglobulin levels was observed throughout gestation, especially during the last trimester. Fourth, increased thyroid volume was common, and goiter formation not uncommon (goiter was found in 9% of women at delivery). In conclusion, the alterations in maternal thyroid function during gestation are intricate and far from fully understood. In areas of marginally low iodine intake, gestation is associated in a significant number of women with relative hypothyroxinemia, increased thyroglobulin, and enlarged thyroid.

Mapping the global distribution of livestock.

Abstract: Livestock contributes directly to the livelihoods and food security of almost a billion people and affects the diet and health of many more. With estimated standing populations of 1.43 billion cattle, 1.87 billion sheep and goats, 0.98 billion pigs, and 19.60 billion chickens, reliable and accessible information on the distribution and abundance of livestock is needed for a many reasons. These include analyses of the social and economic aspects of the livestock sector; the environmental impacts of livestock such as the production and management of waste, greenhouse gas emissions and livestock-related land-use change; and large-scale public health and epidemiological investigations. The Gridded Livestock of the World (GLW) database, produced in 2007, provided modelled livestock densities of the world, adjusted to match official (FAOSTAT) national estimates for the reference year 2005, at a spatial resolution of 3 minutes of arc (about 5×5 km at the equator). Recent methodological improvements have significantly enhanced these distributions: more up-to date and detailed sub-national livestock statistics have been collected; a new, higher resolution set of predictor variables is used; and the analytical procedure has been revised and extended to include a more systematic assessment of model accuracy and the representation of uncertainties associated with the predictions. This paper describes the current approach in detail and presents new global distribution maps at 1 km resolution for cattle, pigs and chickens, and a partial distribution map for ducks. These digital layers are made publically available via the Livestock Geo-Wiki (http://www.livestock.geo-wiki.org), as will be the maps of other livestock types as they are produced.

Temporal cavity solitons in one-dimensional Kerr media as bits in an all-optical buffer

Abstract: Temporal cavity solitons are packets of light persisting in a continuously driven nonlinear resonator. They are robust attracting states, readily excited through a phase-insensitive and wavelength-insensitive process. As such, they constitute an ideal support for bits in an optical buffer that would seamlessly combine three critical telecommunication functions, namely all-optical storage, all-optical reshaping and wavelength conversion. Here, with standard silica optical fibres, we report the first experimental observation of temporal cavity solitons. The cavity solitons are 4 ps long and are used to demonstrate storage of a data stream for more than a second. We also observe interactions of close cavity solitons, revealing for our set-up a potential capacity of up to 45,000 bits at 25 Gbit s−1. More fundamentally, cavity solitons are localized dissipative structures. Therefore, given that silica exhibits a pure instantaneous Kerr nonlinearity, our experiment constitutes one of the simplest examples of self-organization phenomena in nonlinear optics. Using standard silica optical fibres, scientists observe temporal cavity solitons — packets of light persisting in a continuously driven nonlinear resonator. Cavity solitons 4 ps long are reported and used to demonstrate storage of a data stream for more than a second. The findings represent one of the simplest examples of self-organization phenomena in nonlinear optics.

The BioPAX community standard for pathway data sharing

Abstract: Biological Pathway Exchange (BioPAX) is a standard language to represent biological pathways at the molecular and cellular level and to facilitate the exchange of pathway data. The rapid growth of the volume of pathway data has spurred the development of databases and computational tools to aid interpretation; however, use of these data is hampered by the current fragmentation of pathway information across many databases with incompatible formats. BioPAX, which was created through a community process, solves this problem by making pathway data substantially easier to collect, index, interpret and share. BioPAX can represent metabolic and signaling pathways, molecular and genetic interactions and gene regulation networks. Using BioPAX, millions of interactions, organized into thousands of pathways, from many organisms are available from a growing number of databases. This large amount of pathway data in a computable form will support visualization, analysis and biological discovery.

Disaggregating census data for population mapping using Random forests with remotely-sensed and ancillary data

Abstract: High resolution, contemporary data on human population distributions are vital for measuring impacts of population growth, monitoring human-environment interactions and for planning and policy development. Many methods are used to disaggregate census data and predict population densities for finer scale, gridded population data sets. We present a new semi-automated dasymetric modeling approach that incorporates detailed census and ancillary data in a flexible, “Random Forest” estimation technique. We outline the combination of widely available, remotely-sensed and geospatial data that contribute to the modeled dasymetric weights and then use the Random Forest model to generate a gridded prediction of population density at ~100 m spatial resolution. This prediction layer is then used as the weighting surface to perform dasymetric redistribution of the census counts at a country level. As a case study we compare the new algorithm and its products for three countries (Vietnam, Cambodia, and Kenya) with other common gridded population data production methodologies. We discuss the advantages of the new method and increases over the accuracy and flexibility of those previous approaches. Finally, we outline how this algorithm will be extended to provide freely-available gridded population data sets for Africa, Asia and Latin America.