MAFCONS: managing fisheries to conserve ground fish and benthic invertebrate species diversity

MAFCONS is an EC funded project that combines six partners with research activities in the North Sea. It is an applied ecology research project that wants to provide fisheries managers with a mathematical ‘tool’ to adopt a proactive ecosystem management approach. The relationship between fishing, as a disturbance, and the response of the benthic and fish communities, as the change in species diversity, needs to be clearly defined. For it the ecological ‘Huston’s Dynamic Equilibrium Model’ will be tested. This model relates diversity simultaneous to productivity and disturbance. It expresses that a change in diversity caused by a change in disturbance is dependent on the level of productivity. The Huston model and the relevant variables were discussed and evaluated in different workshops. The main objective of this project is to provide a mathematical tool based on the Huston model, that allows to predict the consequences of fisheries management policies on species diversity. Data for diversity and productivity assessment within different ICES rectangles are collected by each partner. The first campaign of the Belgian and Dutch partners coincided with the yearly IBTS survey, executed by the Tridens. At 29 stations Van Veen grab and 2m beam trawl samples were taken. Since October the processing of data started and first benthic species diversity and productivity results are obtained. A second five week campaign is planned for August-September. The first testing of the model starts in February 2005

Upgrading the OMES database: online access to OMES monitoring data using the IMERS web interface

The OMES collection is a database that holds a huge amount of measurement data on stations along the Zeeschelde and Westerschelde. The data collection consists in three main types of data: historical data (1904-1991) derived from literature, more recent data (1995-2007) generated during the OMES monitoring campaigns and some additional data from incidental measurements in the same study area. The measurements vary from water quality and suspended matter to biological data.The OMES project started in 1995 and is a multidisciplinary study on the estuarine environment of the Belgian part of the Scheldt. The main aim of OMES is to create a tool for the Flemish government that can be used as scientific support for the policy on water management of the Scheldt Estuary.In the summer of 2007 the OMES data collection has been integrated as a separate context in the IMERS data system. The Flanders Marine Institute is now responsible for centralizing and management of the newly gathered OMES data and for redistributing the data towards the OMES partners and extern users.The user that is interested in access to and use of the data is presented with a web interface on the OMES website that allows querying the database based on specific search criteria. Search criteria include parameters measured and taxonomic, spatial and temporal scope. The user can visualize the resulting data in tables and export the data to The whole dataset is made available to the project partners on the restricted pages of the OMES website: http://www.vliz.be/projects/omes

Solving variational inequalities defined on a domain with infinitely many linear constraints

We study a variational inequality problem whose domain is defined by infinitely many linear inequalities. A discretization method and an analytic center based inexact cutting plane method are proposed. Under proper assumptions, the convergence results for both methods are given. We also provide numerical examples to illustrate the proposed method

Biotin tagging of MeCP2 in mice reveals contextual insights into the Rett syndrome transcriptome

Mutations in MECP2 cause Rett syndrome (RTT), an X-linked neurological disorder characterized by regressive loss of neurodevelopmental milestones and acquired psychomotor deficits. However, the cellular heterogeneity of the brain impedes an understanding of how MECP2 mutations contribute to RTT. Here we developed a Cre-inducible method for cell-type-specific biotin tagging of MeCP2 in mice. Combining this approach with an allelic series of knock-in mice carrying frequent RTT-associated mutations (encoding T158M and R106W) enabled the selective profiling of RTT-associated nuclear transcriptomes in excitatory and inhibitory cortical neurons. We found that most gene-expression changes were largely specific to each RTT-associated mutation and cell type. Lowly expressed cell-type-enriched genes were preferentially disrupted by MeCP2 mutations, with upregulated and downregulated genes reflecting distinct functional categories. Subcellular RNA analysis in MeCP2-mutant neurons further revealed reductions in the nascent transcription of long genes and uncovered widespread post-transcriptional compensation at the cellular level. Finally, we overcame X-linked cellular mosaicism in female RTT models and identified distinct gene-expression changes between neighboring wild-type and mutant neurons, providing contextual insights into RTT etiology that support personalized therapeutic interventions

Elevating expression of MeCP2 T158M rescues DNA binding and Rett syndrome–like phenotypes

Mutations in the X-linked gene encoding methyl-CpG–binding protein 2 (MeCP2) cause Rett syndrome (RTT), a neurological disorder affecting cognitive development, respiration, and motor function. Genetic restoration of MeCP2 expression reverses RTT-like phenotypes in mice, highlighting the need to search for therapeutic approaches. Here, we have developed knockin mice recapitulating the most common RTT-associated missense mutation, MeCP2 T158M. We found that the T158M mutation impaired MECP2 binding to methylated DNA and destabilized MeCP2 protein in an age-dependent manner, leading to the development of RTT-like phenotypes in these mice. Genetic elevation of MeCP2 T158M expression ameliorated multiple RTT-like features, including motor dysfunction and breathing irregularities, in both male and female mice. These improvements were accompanied by increased binding of MeCP2 T158M to DNA. Further, we found that the ubiquitin/proteasome pathway was responsible for MeCP2 T158M degradation and that proteasome inhibition increased MeCP2 T158M levels. Together, these findings demonstrate that increasing MeCP2 T158M protein expression is sufficient to mitigate RTT-like phenotypes and support the targeting of MeCP2 T158M expression or stability as an alternative therapeutic approach

Rescaled coordinate descent methods for linear programming

We propose two simple polynomial-time algorithms to find a positive solution to Ax=0Ax=0 . Both algorithms iterate between coordinate descent steps similar to von Neumann’s algorithm, and rescaling steps. In both cases, either the updating step leads to a substantial decrease in the norm, or we can infer that the condition measure is small and rescale in order to improve the geometry. We also show how the algorithms can be extended to find a solution of maximum support for the system Ax=0Ax=0 , x≥0x≥0 . This is an extended abstract. The missing proofs will be provided in the full version

A deep cut ellipsoid algorithm for convex programming

This paper proposes a deep cut version of the ellipsoid algorithm for solving a general class of continuous convex programming problems. In each step the algorithm does not require more computational effort to construct these deep cuts than its corresponding central cut version. Rules that prevent some of the numerical instabilities and theoretical drawbacks usually associated with the algorithm are also provided. Moreover, for a large class of convex programs a simple proof of its rate of convergence is given and the relation with previously known results is discussed. Finally some computational results of the deep and central cut version of the algorithm applied to a min—max stochastic queue location problem are reported

The camera of the fifth H.E.S.S. telescope. Part I: System description

In July 2012, as the four ground-based gamma-ray telescopes of the H.E.S.S. (High Energy Stereoscopic System) array reached their tenth year of operation in Khomas Highlands, Namibia, a fifth telescope took its first data as part of the system. This new Cherenkov detector, comprising a 614.5 m^2 reflector with a highly pixelized camera in its focal plane, improves the sensitivity of the current array by a factor two and extends its energy domain down to a few tens of GeV. The present part I of the paper gives a detailed description of the fifth H.E.S.S. telescope's camera, presenting the details of both the hardware and the software, emphasizing the main improvements as compared to previous H.E.S.S. camera technology.Comment: 16 pages, 13 figures, accepted for publication in NIM