The first direct detection of gravitational waves opened the possibility of mapping the Universe via this new and independent messenger.

Promotor: K. Kuijken, Co-Promotor: H. Hoekstra

One of the most important correlation functions in physics, especially in cosmology, is the energy density, which describes how much energy is present at each point in spacetime due to matter fields. A key contribution to the energy density of the primordial universe comes from gravitational waves (GWs),…

We explored the Universe using weak gravitational lensing, a phenomenon that occurs when light from distant galaxies is bent by the gravitational fields of closer cosmic objects, much like how a lens distorts light.

Of all the mass in our Universe, 80% is thought to consist of a hypothetical and invisible substance called dark matter (DM).

In this work, I explore the creation of new methods that optimize simulations of the gravitational N-body problem. Specifically, I take advantage of the recent popularity of Machine Learning methods to find tools that can suit this problem.

How do societies move forward with sustainable, effective and efficient management of Earth's water resources?

In astronomy, the interpration of observations and measurements plays a crucial role: we rely purely and fundamentally on the information that reaches us as observers. And 80% of all matter in the universe is undetectable directly.

On 27 January 2022 Tjahjono Prasodjo successfully defended a doctoral thesis and graduated.

Leiden University is committed to reducing our water consumption.

We investigate water quality and want to understand the effects of human interference on aquatic biodiversity.

Promotor: Prof.dr. S. Portegies Zwart

Promotor: M.T.M. Koper, Co-Promotor: L.B.F. Juurlink

Water is all around us and is vital for all aspects of life. Studying the various compounds and life forms that inhabit natural waters lets us better understand the world around us.

In this thesis we study the landscape of gravitational models which modify GR by introducing an additional scalar degree of freedom (d.o.f.) to source Cosmic Acceleration.

To design the ideal water oxidation catalyst, understanding of the catalytic mechanism and decomposition pathways is essential.

Human activity, such as pollution, may disturb the balance of living water systems, which has consequences for biodiversity, but also for other functions such as water purification. Leiden University maps living water systems using the most advanced technologies.

The International Course on Water Use and Management in Cagayan Valley The Philippines (2011-2015)

This project investigates ancient water management of streams, springs and runoffs on the archaeological site of Monte Albán, Mexico, as a means to contribute with different stakeholders in the development of sustainable solutions to water problems today such as floods and scarcity.

Astronomical observations of cold regions in the universe show a rich inventory of ices. Part of these ices may end up on planets like our own, but in that journey they will be exposed to considerable amounts of radiation.

Improving environmental risk assessment of pesticides in surface waters

While ecosystems have concrete benefits for human society, these benefits are typically overlooked in decision-making.

This thesis examines the impacts and challenges of water use of electric power system. This thesis found that there are large differences in water use of electricity technologies, with hydropower and thermal power being two large water users.

Before the large scale use of renewable energy sources can be implemented in our society, the storage of electrical energy needs to be tackled. Storage the energy as hydrogen via the reduction of protons is a good option.

In this dissertation, the synthesis and characterization of a series of iron complexes based on different ligand platforms are described.

In the search for sustainable energy solutions, the idea of artificial photosynthesis has been proposed as an approach with which to use water and sunlight to produce hydrogen.

How does the vision of problems and solutions from

Amerindian intra- and inter-insular relationships and social organization in the pre-colonial Windward Islands.

As a virtually inexhaustible source, solar energy plays a major role in future global energy scenarios.

Promotor: M.T.M. Koper, Co-promotor: J.B.F. Juurlink

In this dissertation iron-based homogeneous catalysts were synthesized, characterized and investigated for water oxidation activity.

Understanding the water use of power production is an important step to both a sustainable energy transition and an improved understanding of water conservation measures. However, there are large differences across the literature that currently present barriers to decision making.

Promotor: M.T.M. Koper, Co-promotor: L. Juurlink

The main question I want to answer is about the mutual influence between the cultural and settlements changes that occurred between the Bronze and the Early Iron Age in Margiana and the management of water resources.

Climate change is one of the largest challenges faced by humanity. To combat this research into alternatives to fossil fuels is ongoing. Dihydrogen is considered a good alternative fuel, since its burning only forms water.

AI:Liner develops cutting-edge digital solutions for sewer asset management while ensuring responsible AI adoption through comprehensive social science research and ethical frameworks.

Promotor: M.T.M. Koper, Co-Promotor: F. Calle-Vallejo

At the largest scales, two ingredients dictate the distribution of matter in the Universe. The first is dark matter, acting as an invisible scaffolding held together by gravitational forces.

It's one of the big cosmology debates: the universe is expanding, but how fast exactly? Two available measurements yield different results. Leiden physicist David Harvey adapted an independent third measurement method, using the light warping properties of galaxies predicted by Einstein. He published…

This thesis investigates the structural evolution and assembly of galaxies since the first few billions years after the big bang.

CML report 192

Three major research projects involving Leiden scientists have been awarded a grant from NWO’s Gravitation Programme. The projects are on innovation processes, organs-on-chips and quantum software.

Leiden University is involved in five new NWO Gravitation projects. Two relate to mental disorder and the remaining three to a healthy lifestyle, the combination of human and artificial intelligence, and the special relationship between plants and microbes.

We report new computational and experimental evidence of an efficient and astrochemically relevant formation route to formaldehyde (H2CO). This simplest carbonylic compound is central to the formation of complex organics in cold interstellar clouds and is generally regarded to be formed by the hydrogenation…

Ice, the solid state of water, plays an important role on our planet as well as the entire universe.Despite the fact that an individual water molecule has a very simple structure, its chemical bonding in the solid phase can be surprisingly complex.

Publication on the excavations at Roman fort Matilo in Leiden