לוח שנה משולב

In our LCDM paradigm, galaxies form and reside in dark matter halos. Establishing the (statistical) relation between galaxies and dark matter halos, the `Galaxy-Halo connection', therefore gives important insight into galaxy formation, and also is a gateway to using the distribution of galaxies to constrain cosmological parameters. After a brief introduction to how clustering and gravitational lensing can be used to constrain the galaxy-halo connection, I show that several independent analyses all point towards a significant tension in cosmological parameters compared to the recent CMB results from the Planck satellite. I discuss the potential impact of assembly bias, and present satellite kinematics as a complementary and competitive method to constrain the galaxy-halo connection. After a brief historical overview of the use of satellite kinematics, I present two new analyses, and show how they can be used to improve our knowledge of the galaxy-halo connection.

Atherosclerosis causes heart attack and stroke and is a major fatal disease in the Western world. The formation of atherosclerotic plaques in the artery walls is the result of LDL particle uptake, and consequently of cholesterol accumulation in macrophage cells. Excess cholesterol accumulation eventually results in cholesterol crystal deposition, the hallmark of mature atheromas. We study the formation of cholesterol monohydrate crystal polymorphs on lipid bilayer membranes and in cells enriched with cholesterol. This work may provide information on the crystal growth mechanisms involved, once the factors that favor the formation of different structures are understood

The Lindblad equation allows to explore general properties of open quantum systems. Whenever strong decoherence processes are present, one expects the system to become classical. Namely, the evolution of the surviving diagonal terms of the density matrix is Markovian. Surprisingly enough, many interesting aspects of the quantum system can be inferred from the classical limit. Among which we will explore some transport properties as well as a condensation transition for interacting quantum particles. Moreover, we will be interested in the quantum corrections to Fick’s law in diffusive systems

Information theory, originally developed for mathematical analysis of communication systems, has been applied to molecular biology for decades. In this context, the concept of entropy is utilized to measure the compositional complexity of genomes, wherein all of the hereditary information necessary to build and maintain an organism is stored. The recent explosion in the availability of genomic data, coupled with the considerable improvements in computational processing power, presents opportunities for investigating genomes far beyond the scope and depth previously achievable. In this work, we propose to characterize the informational properties of ~5000 genomes by assessing the statistical abundance and sequence space coverage of fixed-length substrings (known as ‘kmers’). Additionally, we aim to identify unique kmers that can be used as genome-specific markers for taxonomic profiling purposes.

The 100-year old Sabatier reaction, i.e. catalytic CO2 hydrogenation, is now seeing a renaissance due to its application in Power-to-Methane processes for electric grid stability and potential CO2 emission mitigation [1]. To date however, the fundamentals of this important catalytic reaction are still a matter of debate. This is partly due to the structure sensitive nature of CO2 hydrogenation: not all surface atoms of the active phase nanoparticles have the same specific activity. Recently, we have showed how the mechanism of catalytic CO2 methanation depends on Ni nanoparticle size using a unique set of well-defined silica-supported Ni nanoclusters (in the range 1-7 nm) and advanced characterization methods (i.e., operando FT-IR, and operando quick X-ray absorption spectroscopy) [2]. By utilizing fundamental theoretical concepts proving why CO2 is structure sensitive, and how CO2 is activated mechanistically and linking spectroscopic descriptors to these fundamental findings we ultimately leverage our understanding with a toolbox of structure sensitivity, and a library of reducible and non-reducible supports (SiO2, Al2O3, CeO2, ZrO2 and TiO2), tuning the selectivity and activity of methanation over Ni [3]. For example, we show that CO2 hydrogenation over Ni can and does form propane. This work contributes to our ability to produce “ideal” catalysts by improving the understanding of the catalytic sites and reaction pathways responsible for higher activity and even C-C coupling. This toolbox is thus not only useful for the highly active and selective production of methane within the Power-to-Methane concept, but also provides new insights for CO2 activation towards value-added chemicals thereby reducing the deleterious effects of this environmentally harmful molecule.