Integrated Calendar

I will review the top scientific discoveries achieved with the Hubble Space Telescope since its launch in 1990.
I will cover topics ranging from Dark Energy to observations
of Jupiter, and from the cosmic global star formation rate
to the compositions of the atmospheres of extrasolar planets.
Along the way, I will show some of the breathtaking images
taken by Hubble following the recent Servicing Mission.

The abstract: Models of mammalian regulatory networks controlling gene expression have been inferred from genomic data, yet have largely not been validated. We present an unbiased strategy to systematically perturb candidate regulators and monitor cellular transcriptional responses. We
apply this approach to derive regulatory networks that control the transcriptional response of mouse primary dendritic cells (DCs) to pathogens. Our approach revealed the regulatory functions of 125 transcription factors, chromatin modifiers, and RNA binding proteins and
constructed a network model consisting of two dozen core regulators and 76 fine-tuners that help explain how pathogen-sensing pathways achieve specificity. This study establishes a broadlyapplicable, comprehensive and unbiased approach to reveal the wiring and functions of a regulatory network controlling a major transcriptional response in primary mammalian cells.

Cosmological observations are reaching maturity to start testing the inflationary paradigm in detail. I will discuss some of the recent and most exciting of these observations and review what constraints they impose already on the inflaton. In the second
part of this talk I will describe an inflationary model that is built within the SUSY framework and that is very predictive on how inflation should happen.

How complex patterns of cells are generated during embryonic development has been a central question in science for centuries. In the past few decades many of the molecular components involved in these processes (signaling molecules, genes, and proteins) and their interactions have been identified. While we can use this knowledge to draw a detailed interaction network of genes and proteins, it is often unclear how these genetic networks generate the observed patterns. In this talk, I will describe the experimental and theoretical analysis of a class of developmental processes that lead to ‘fine grained’ patterns: patterns with a typical length scale of one cell (e.g. alternating patterns of cell fates or sharp boundaries between regions of cells). In animals, many of these fine grained patterns rely on the Notch signaling pathway which is the canonical communication system between neighboring cells. We use quantitative time lapse microscopy of mammalian cells together with mathematical modeling to study how the properties of the Notch signaling pathway affect pattern formation. We show how the Notch signaling pathway integrates extracellular and intracellular signals to generate a sharp switch between two mutually exclusive signaling states; a ‘sender’ state in which a cell can predominantly send signals, and a ‘receiver’ state in which a cell predominantly ‘receives’ signals. Furthermore, we show how this signaling switch can play an important role in the differentiation of neighboring cells into distinct fates in several developmental patterning processes. Finally, I will describe how the experimental and theoretical approach developed in this study can be generalized to address a variety of basic questions in developmental patterning that cannot easily be investigated with standard biological techniques.