11 Postdoctoral Fellowship at Umea University, Sweden

Linear algebra expressions are evaluated in an efficient and robust way by mapping them to a carefully chosen sequence of calls to optimized functions as offered by libraries such as BLAS and LAPACK. The mapping is by no means unique, and different mappings differ in terms of time, space, and accuracy. When the sizes of the matrices are unknown at compile-time, as is often the case, then the problem is further complicated by the fact that no single mapping is optimal for all combinations of matrix sizes. As a consequence, any code generated (at compile-time) to evaluate the at run-time) must consist of more than just a single sequence of function calls.

We recently received a grant from the Swedish Research Council to investigate how to effectively compile linear algebra expressions when the matrix sizes are unknown at compile-time. The project aims to address the problem using e-graphs. An e-graph is a data structure commonly used in automated theorem provers and recently popularized for optimizing compilers and many other optimization tasks. We hypothesize that an e-graph would be an effective tool for discovering and encoding a large set of alternative ways of evaluating a particular expression with unspecified matrix sizes. When a concrete expression is evaluated at run-time, thus revealing the matrix sizes, an extraction algorithm can identify an optimal evaluation scheme for that particular instance of the expression from the compiled e-graph. This project extends our previous work on linear algebra compilers: https://linnea.cs.umu.se/

Our research group studies the structural and functional aspects of horizontal gene transfer via Type 4 Secretion Systems. Due to the increasingly large spread of antibiotic-resistant bacteria, it is important to understand the basic mechanisms and structure of the very large protein complexes that facilitate this gene transfer. 

The overall goal of this project is to study the function and structure of Type 4 Secretion Systems from Gram-positive bacteria. In part depending on the background and interests of the applicant, the project will involve a combination of both in vitro techniques, such as cloning (both standard and knock-in/knock-out via homologous recombination), expression and (membrane) protein purification, single particle electron microscopy, x-ray crystallography, as well as in vivo methods like conjugation and biofilm formation assays or fluorescence microscopy. For recent publications resulting from our work on this system, see e.g. Breidenstein et al, 2025, Sun et al, 2024 mBio, Sun et al, 2023 eLife and Jäger et al, 2022 Structure. 

As a postdoctoral fellow, you are expected to independently conduct your own research project, including publications and engagement with the surrounding community. The research will be focused on educational work with a focus on one or more of the aesthetic subjects: Visual Arts, Music and Sloyd. You are expected to contribute to the development of the department’s research environment, for example by initiating collaborations with other researchers at the department, participating in and organizing seminars and other academic gatherings. You are also expected to attend other meetings and staff activities at the department, such as workplace meetings and staff days. Teaching at the undergraduate, graduate, and doctoral level may occur up to a maximum of 20%.

mRNA structures play important roles in controlling cell biology responses under different conditions. However, the precise mechanisms by which mRNA conformational changes regulate cellular stress responses remain poorly understood. The aim of the project is to gain a better understanding of how dynamic mRNA structures influence RNA stability, translation efficiency in response to changes in the cellular environment. To address these questions, we will determine RNA structures in vivo using cutting-edge transcriptome-wide RNA structure probing techniques that together with computational models and machine learning algorithms will generate accurate in vivo RNA structural predictions.

The postdoc position is supported by a new Water4All Transnational Project: Monitoring river metabolism to assess ecosystem services (BREATHE). BREATHE’s broadest goal is to co-design an international sensor-based river observation system, emphasizing the use of dissolved oxygen and river metabolism as tools to quantify aquatic ecosystem services in the face of environmental change. BREATHE is made up of six international groups, with each participating country focused on advancing how aquatic sensors can be used to understand regionally-pressing environmental challenges, from water regulation, to forestry, to climate change. Included in this work will be efforts to engage stakeholders in 1) co-designing workflows that interconnect sensor data collection, integration, and modelling and 2) co-constructing case studies to demonstrate how this workflow may be applied at the local scale but also integrated internationally.

This postdoc position will focus largely on using dissolved oxygen sensors to understand how peatland restoration in the Swedish landscape alters downstream water quality and aquatic ecosystem functioning. Peatlands are defining features of boreal landscapes, playing critical roles in carbon storage and water quality. There is currently much debate in Sweden regarding how to manage and/or restore historically-ditched peatlands, with little consideration of what this decision may mean for downstream aquatic ecosystems. The postdoc will lead the acquisition and analysis of aquatic sensor data collected from a network of streams draining ditched, restored, and pristine peatlands already established across Sweden.

This interdisciplinary project will develop a framework for predicting and steering the evolution of multidrug resistance in the opportunistic pathogen Pseudomonas aeruginosa using a combination of mathematical modeling, experimental evolution and genomics. The project is a collaboration between the Peter Lind lab at the Department of Molecular Biology and the Eric Libby lab at the Integrated Science Lab (IceLab) that is funded by the Swedish Research Council.

Our team of mathematical and experimental biologists will work to combine experimental data with mechanistic mathematical models of the molecular networks that drive resistance evolution to predict the evolution of bacterial populations in the laboratory. Later, focus will be on guiding bacterial populations to desirable genetic outcomes by predicting the environmental conditions likely to lead to a certain evolutionary trajectory.

You will be a part of the development of a larger effort aimed at the development of light-emitting electrochemical cells (LECs). The LEC is a novel technology that is attracting interest from both academia and industry since it can be thin, lightweight and flexible, since it can be highly sustainable, and because it can be fabricated in its entirety by ambient-air printing. The unique and enabling feature of the LEC is the in-situ formation of a light-emitting p-i-n junction in the active material by electrochemical doping.

Your primary task will be the investigation of the exciton dynamics in this electrochemically formed doping structure, with the goal of establishing design guidelines for the realization of LECs with improved emission performance. For these investigations you will utilize a combination of advanced spectroscopy, electrochemistry and device design and development. You will collaborate closely with other members of the group as well as external academic and industrial partners. For information on relevant background research, please refer to our earlier publications: DOI: 10.1002/adma.202310156, doi: 10.1038/s41467-025-55954-3 and DOI: 10.1002/adma.202107849

This recruitment is connected to the Wallenberg Initiative Materials Science for Sustainability (WISE, wise-materials.org). WISE, funded by the Knut and Alice Wallenberg Foundation, is the largest-ever investment in materials science in Sweden and will encompass major efforts at Sweden’s foremost universities over the course of 10 years. The vision is a sustainable future through materials science. Read more: https://wise-materials.org 

All early-stage researchers recruited into the WISE program will be a part of the WISE Research School https://wise-materials.org/research-school/ an ambitious nationwide program of seminars, courses, research visits, and other activities to promote a strong multi-disciplinary and international network between PhD students, postdocs, researchers, and industry. 

The project’s aim is to contribute to sustainable production of cement clinker and quicklime. Specifically, electrified manufacturing processes will be studied, aiming for a concentrated process gas suitable for carbon capture and utilization or storage.

We are now seeking a postdoctoral researcher who will work on sampling and analysis of products from several pilot-scale facilities across Europe. The characterization includes all conventional methods for product quality, and detailed studies to understand the connection between the new process conditions and the resulting product quality.

The work involves planning and conducting precise sampling, sample preparation, and analysis of products from three different pilot-scale facilities for the electrified production of cement clinker and burnt lime. The facilities are located in Sweden, Finland, and Norway.

The tasks include carefully planning the work so that fresh representative samples are immediately sent to the respective analysis, leading the analysis work, and taking responsibility for data quality. The work also includes compiling data and evaluating information, participating in project meetings, and leading the work to publish results.

The research environment at the Thermochemical Energy Conversion Laboratory and the Center for Sustainable Production of Cement and Quicklime at Umeå University hosts the research. The environment is interdisciplinary and characterized by collaboration at the intersection of energy technology, physics, and chemistry.

The past two decades has seen a major global focus on understanding the linkages between the aboveground and belowground components of ecosystems, and significant research effort has concentrated on understanding the feedback between plant communities, soil communities and ecosystem processes. There is also growing interest in how the linkages between these two components, and their impacts on ecosystem-level properties, drive feedbacks between the biosphere and atmosphere. Despite the profile that this topic is attracting, we still have a very limited knowledge of how aboveground-belowground linkages and their effects on ecosystems are driven by environmental context, for example about how they may vary across contrasting ecosystems, along environmental gradients, or in response to anthropogenic global change drivers.

The research will aim to fill this gap by performing measurements aimed at quantifying processes that drive ecosystem carbon fluxes and stocks in a large ongoing replicated field experiment on a group of lake islands in the boreal forested zone of northern Sweden that collectively represent 5000-year post fire chronosequence. The experiment was initiated in 1996 and involves continued removal of different subsets of the vegetation in different plots; it is now in its 29th year. This study system and experiment is unique globally and has resulted in several publications in leading journals including 7 in Science and Nature. The research will be generously funded through a 5-year grant from the Wallenberg Scholars award scheme.

The planned work for this announcement consists of performing measurements on the field experiment and collecting samples from the field for laboratory analyses. This will include quantifying net ecosystem exchange of carbon through gas flux measurements, determining carbon stocks and changes, and measuring decomposer processes that underpin ecosystem carbon dynamics. The selected candidate will take part in designing their project and take responsibility for its implementation from data collection through to publication. Opportunities also exist for collaboration with other researchers working on the study system and experiment, particularly in relation to linking ecosystem carbon dynamics to the structure and function of the soil microbial community. 

The Postdoc will work with Prof. David Wardle (Umeå University), and key collaborators will include Prof. Daniel Metcalfe and Assoc. Prof. Micael Jonsson (both at Umeå University) and Prof. Paul Kardol (Swedish University of Agricultural Sciences).