Modeling the clonal heterogeneity of stem cells

Recent experimental studies suggest that tissue stem cell pools are composed of functionally diverse clones. Metapopulation models in ecology concentrate on collections of populations and their role in stabilizing coexistence and maintaining selected genetic or epigenetic variation. Such models are characterized by expansion and extinction of spatially distributed populations. We develop a mathematical framework derived from the multispecies metapopulation model of Tilman et al (1994) to study the dynamics of heterogeneous stem cell metapopulations. In addition to normal stem cells, the model can be applied to cancer cell populations and their response to treatment. In our model disturbances may lead to expansion or contraction of cells with distinct properties, reflecting proliferation, apoptosis, and clonal competition. We first present closed-form expressions for the basic model which defines clonal dynamics in the presence of exogenous global disturbances. We then extend the model to include disturbances which are periodic and which may affect clones differently. Within the model framework, we propose a method to devise an optimal strategy of treatments to regulate expansion, contraction, or mutual maintenance of cells with specific properties

Physics of Neutron Star Crusts

The physics of neutron star crusts is vast, involving many different research fields, from nuclear and condensed matter physics to general relativity. This review summarizes the progress, which has been achieved over the last few years, in modeling neutron star crusts, both at the microscopic and macroscopic levels. The confrontation of these theoretical models with observations is also briefly discussed.Comment: 182 pages, published version available at <http://www.livingreviews.org/lrr-2008-10

Knowledge in process? Exploring barriers between epidemiological research and local health policy development

The Redes de Trueque (RT) thrived during the economic crisis of 2001 – 2002 in Argentina and still stand out as one of the largest Complementary Currency System in the world. These local exchange networks reach a large scale during times of severe economic distress, but as large non-state initiatives, they pose a governance problem. Four types of governance systems were structured within the Argentine RT, of varying degrees of sustainability: a) loosely regulated market systems, b) hierarchies, c) associational regional networks, and d) local communities. Based on a four dimensional analytical framework, this paper discusses the rules of governance and sustainability of the governance systems in the RT. It found that some became more sustainable than others in terms of achieving combinations of scale and organisational modes

Search for neutral MSSM Higgs bosons decaying to a pair of tau leptons in pp collisions

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Measurement of prompt J/ψ pair production in pp collisions at √s = 7 Tev

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Study of hadronic event-shape variables in multijet final states in pp collisions at √s=7 TeV

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Constraints on parton distribution functions and extraction of the strong coupling constant from the inclusive jet cross section in pp collisions at √s=7 TeV

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Searches for electroweak production of charginos, neutralinos, and sleptons decaying to leptons and W, Z, and Higgs bosons in pp collisions at 8 TeV

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Measurement of top quark–antiquark pair production in association with a W or Z boson in pp collisions at √s=8 TeV

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