ETH Zürich Foundation

The synthesis and structural characterization of a new metal organic framework, UoB-100(Dy), is reported. Average structure refinements indicate that the node is disordered between two orientations of the nonanuculear secondary building unit (SBU). By performing 3D diffuse scattering (DS) analysis and Monte Carlo (MC) simulations, we confirm the presence of strong correlations between the metal clusters of UoB-100(Dy). These nodes assemble into a complex and novel nanodomain structure. Quantum mechanical calculations identify linker strain as the driving force behind the nanodomain structure. The implications of such a nanodomain structure for the magnetic, gas storage, and mechanical properties of lanthanide MOFs are discussed.

Perturbative expansions in quantum field theory diverge for at least two reasons: the number of Feynman diagrams increases dramatically with the loop number and the process of renormalization may make the contribution of some diagrams large. We give an example of the second problem, from an ultra-violent renormalon of ϕ3 theory in 6 dimensions, where we can compute to very high loop-order. Taming this renormalon involves recent work on resurgence. This challenge is much more demanding than the corresponding problem for Yukawa theory in 4 dimensions.

Boundary layers over complex, mountainous terrain are characterized by multi-scale, complex flow structures, where scale separation poses a fundamental challenge. In this study, we apply the novel multiresolution coherent spatio-temporal scale separation (mrCOSTS) method to LIDAR observations and numerical data of the velocity components of complex mountain boundary-layer flow. We are able to identify three distinct time scales (i.e., turbulent scales, mountain boundary layer, and diurnal scales) and explore the underlying physical processes. Furthermore, we identified the dominant flow patterns for each time scale, e.g., down- and up-valley flows, cross-valley vortices, small-scale turbulence, and large evening transition eddies . Applying mrCOSTS to simulated velocity components enables us to identify how coherent structures and the flow patterns are represented at various mesh sizes in the model. Using mrCOSTS we trivially retrieved complex dynamics that were previously difficult to resolve, enabling a direct, scale-aware evaluation between the LIDAR observations and model results.

Workshop for doctoral students in the humanities and social sciences held at the Collegium Helveticum in Zürich on 14 February 2019. The event explored how digital tools and infrastructures are transforming historical and social-scientific source work. Participants discussed methodological challenges in searching, processing, and mediating digital sources. The workshop featured short research presentations and thematic discussions rather than formal papers.

Workshop for doctoral students in the humanities and social sciences held at the Collegium Helveticum in Zürich on 14 February 2019. The event explored how digital tools and infrastructures are transforming historical and social-scientific source work. Participants discussed methodological challenges in searching, processing, and mediating digital sources. The workshop featured short research presentations and thematic discussions rather than formal papers.

Subglacial processes are key to glacier dynamics, yet remain poorly constrained due to limited in-situ observations. We use continuous seismic and GNSS measurements to investigate summer subglacial processes in 2022 at Sermeq Kujalleq in Kangia (SKK; Jakobshavn Isbræ), Kalaallit Nunaat (Greenland). Seismic analysis (HVSR) captured changes in ice-bedrock coupling, while GNSS tracked surface velocities. By late June, a low-frequency resonance peak emerged, persisting until late July. This coincided with a ~20% acceleration in ice flow, ~8 cm of vertical uplift, and simulated elevated basal water pressures. HVSR data captured the start of the melt season, revealing a shift from an ice-bedrock state, where limited meltwater maintains strong coupling, to a decoupled state driven by sustained meltwater input that reduces basal rigidity. Elastic modeling supported the link between lower resonance frequencies and decoupling. These findings highlight how glaciated areas surrounding ice streams, although slower flowing, can still exhibit fast-changing dynamics.

Global Ionospheric Maps (GIMs) are essential in Global Navigation Satellite System (GNSS) applications, particularly for correcting ionospheric delays in single-frequency positioning. GIMs are mainly derived from dual-frequency GNSS observations, but the uneven distribution of ground stations-sparse over oceans-reduces accuracy in these regions. Alternative space-geodetic techniques, such as satellite altimetry and GNSS radio occultation (GNSS-RO), provide ionospheric information over oceans but differ from GNSS-derived vertical total electron content (VTEC) in terms of orbital altitudes and observation geometries. Moreover, the sparsity of satellite altimetry and GNSS-RO data on a daily scale poses additional challenges. We present a framework that integrates GNSS, Jason-3 altimetry, and COSMIC-2 GNSS-RO observations into GIMs using machine learning (ML). First, satellite altimetry and GNSS-RO VTEC were calibrated to GNSS VTEC. To mitigate daily data sparsity, we built daily background models with XGBoost, each covering 80 day time spans of satellite altimetry and GNSS-RO observations capturing medium-term ionospheric characteristics. These background models generated virtual VTEC samples to supplement regions lacking GNSS data for training our Neural Network (NN)-based GIMs. Tests over three regions (Hawaii, Atlantic and Antarctic) in 2024 show mean absolute error (MAE) reductions of 37 %, 10 %, and 33 % compared to GIMs that do not incorporate local GNSS data. Evaluation with single point positioning indicates improved 3D accuracy, and external validation with Sentinel-6A altimetry demonstrates a 0.5 TECU reduction in residual standard deviation when including VTEC from the background model.

The Colombian Amazon is a biodiversity hotspot that provides vital ecosystem services; however, deforestation has intensified in recent decades. Particularly, Caquetá Department registers an annual deforestation rate of 0.77% (~685 km 2 year -1 ), roughly twice the average rate for tropical South America. Cattle ranching, a key economic sector, plays a central role in deforestation, as low productivity and pasture and soil degradation due to inadequate management practices often lead to expansion of pasturelands into forest. Here, we review the challenges faced by Caquetá’s cattle sector including the negative environmental impact caused by inadequate cattle ranching management, and advocate for sustainable intensification practices to restore the existing degraded pastures and soils and enhance the region’s development and sustainability. Strategic implementation of improved grass–legume pastures that can provide nitrogen by N 2 fixation to these nutrient limited soils, and silvopastoral systems including trees and shrubs to enhance soil carbon storage, increase biodiversity, and mitigate greenhouse gas emissions, have been successfully tested in the region. These management practices can revert the ongoing pasture and soil degradation and increase the efficiency of cattle production while reducing environmental impacts and delivering ecosystem services. Moreover, sustainable intensification also strengthens the social and economic sustainability of small- and medium-sized cattle farms, thereby supporting local livelihoods. However, adoption of sustainable intensification and restoration practices remains limited due to financial, social, and logistical barriers. Public policies and financial support are crucial to overcoming these challenges. While sustainable intensification and restoration of the existing degraded pastures alone cannot stop deforestation, it offers a worthwhile path toward a more sustainable cattle sector and regional development.

We present a framework to model and provide numerical evidence for compartmentalization in the yeast endoplasmic reticulum. Measurement data is collected and an optimal control problem is formulated as a regularized inverse problem. To our knowledge, this is the first attempt in the literature to introduce a PDE-constrained optimization formulation to study the kinetics of fluorescently labeled molecules in budding yeast. Optimality conditions are derived and a gradient descent algorithm allows accurate estimation of unknown key parameters in different cellular compartments. For the first time, the numerical results support the barrier index theory suggesting the presence of a physical diffusion barrier that compartmentalizes the endoplasmic reticulum by limiting protein exchange between the mother and its growing bud. We report several numerical experiments on real data and geometry, with the aim of illustrating the accuracy and efficiency of the method. Furthermore, a relationship between the size ratio of mother and bud compartments and the barrier index ratio is provided.

We present a framework to model and provide numerical evidence for compartmentalization in the yeast endoplasmic reticulum. Measurement data is collected and an optimal control problem is formulated as a regularized inverse problem. To our knowledge, this is the first attempt in the literature to introduce a PDE-constrained optimization formulation to study the kinetics of fluorescently labeled molecules in budding yeast. Optimality conditions are derived and a gradient descent algorithm allows accurate estimation of unknown key parameters in different cellular compartments. For the first time, the numerical results support the barrier index theory suggesting the presence of a physical diffusion barrier that compartmentalizes the endoplasmic reticulum by limiting protein exchange between the mother and its growing bud. We report several numerical experiments on real data and geometry, with the aim of illustrating the accuracy and efficiency of the method. Furthermore, a relationship between the size ratio of mother and bud compartments and the barrier index ratio is provided.