Integrated Calendar

A fundamental problem in neuroscience is to elucidate the relationship between neuronal network anatomy and its functional dynamics. The nematode worm C. elegans is an ideal model to study these problems. Its nervous system has just 302 neurons and all synaptic connections between them have been fully mapped. Using a large-scale Ca2+-imaging approach, we previously discovered nervous system wide neuronal population dynamics in the worm that encode action commands. These dynamics feature various network attractor states during which neurons coordinate and synchronize their activities, thereby providing functional interaction maps. In this talk, I will discuss unpublished work where we combine graph-theoretical and experimental approaches to understand which anatomical features in network connectivity relate to these functional dynamics and interactions between neurons.

Less is more! By using extremely low power refocusing π pulses in echo train sequences the coherence lifetime, T2, of the central transition of half-integer quadrupolar nuclei can be largely extended. This effect is particularly impactful in systems dilute in NMR active nuclei, where sources of decoherence are scarce. Crucial to this lifetime extension is the avoidance of coherence transfer to short-lived non-symmetric “killing” transitions. For 17O in polycrystalline α-quartz we were able to retain coherent magnetization for over four minutes on the transverse plane. This translates into enormous sensitivity gains for echo train acquisition after addition of the long living echoes. By combining satellite population transfer schemes with a low power CPMG on 17O in quartz, we obtain over a 1000-fold sensitivity enhancement compared to a spectrum from a free induction decay acquired at a more typical rf field strength. This enhancement allows the acquisition of a highly resolved 17O spectrum within less than one hour, despite its low natural abundance and a spin-lattice relaxation time of approximately 900 s. In this talk I will present a thorough analysis of the effects of pulse power on the echo intensity, coherence lifetime and line shape integrity. Finally, we apply this approach on various crystalline and glassy inorganic solids, including other low sensitivity nuclei, such as 33S and 45Ca, showing that it can be beneficial for a large number of systems.

The ATLAS and CMS experiments have made three major discoveries: The discovery of an elementary spin-zero particle, the discovery of the mechanism that makes the weak interactions short-range, and the discovery of the mechanism that gives the third generation fermions their masses. I explain how this progress in our understanding of the basic laws of Nature was achieved.

The soil spectroscopy discipline has been progressed over the past two decades quite remarkably. Many portable point spectrometers became available through that time where recently also image spectrometers have become quite popular. The technology was used in the laboratory, field, and airborne levels and provided a new capability for a rapid and quantitative view of a large number of samples. At the same time platforms were also developed to carry the new family of sensors for remote sensing applications of large areas using ground and airborne vehicles ( manned and un-manned) and recently even satellites. This progress has led to a large number of activities in exploiting the spectroscopy for many applications within the soil science discipline. As the data acquisition increases and the soil spectral database has been enlarged, a new technique to compile soil spectral database together with methods to effectively analyze them has also been developed. To that end, activities to deal with the data mining process using big databases were successfully adopted from other disciplines while also designed especially for the soil spectroscopy activity. The results demonstrated that soil spectroscopy could be used for many applications from different domains such as soil mapping, precision agriculture, and laboratory work and can progress the soil science discipline quite forward. In this talk, we will review the history of soil spectroscopy from the first spectrometer and platform to the present situation. A particular emphasis will be given to the recent applications that have been developed in our group and to the future capability of this critical technology from all perspectives and to the new horizon it may open as expressed by space agencies such as NASA, ESA, ASI, JAXA, ISA and DLR.

> Conventional computational methods often create a dilemma for fluid–structure interaction problems. Typically, solids are simulated using a Lagrangian approach with grid that moves with the material, whereas fluids are simulated using an Eulerian approach with a fixed spatial grid, requiring some type of interfacial coupling between the two different perspectives. Here, a fully Eulerian method for simulating structures immersed in a fluid will be presented. By introducing a reference map variable to model finite-deformation constitutive relations in the structures on the same grid as the fluid, the interfacial coupling problem is highly simplified. The method is particularly well suited for simulating soft, highly-deformable materials and many-body contact problems, and several examples will be presented. This is joint work with Ken Kamrin (MIT).