Balsaminaceae is a diverse plant family characterized by a huge floral morphological diversity.

Promotor: J. Zaanen, Co-Promotor: V. Juricic

In the first part of this thesis we study the geometry of folding patterns.

“Transitional justice” is a field of practice, policy and study that focuses on the ways that societies respond to legacies of large-scale atrocities though tribunals, truth commissions, reparations, and other mechanisms.

LCD screens use liquid crystals which have a high degree of order, even though they form a fluid. A new theory maps out the interplay between order, temperature and symmetry. Publication in Physical Review X.

Promotor: J. Zaanen

For the first time ever, Leiden biologists have found that the ‘nose’ of spirochetes – worm-shaped bacteria – have a two-fold symmetry. A remarkable discovery, as the ‘nose’ of every other bacterium has been found to have a six-fold symmetry. First author Alise Muok wrote a popular blog about the findings…

Promotor: Prof.dr.ir. J.W.M. Hilgenkamp, Prof.dr. J. van den Brink

In this thesis, I targeted the orchid genus Lepanthes, one of the six genera of angiosperms that surpasses 1,000 species in the Neotropics, as a study model to investigate the evolutionary processes that promoted species diversifications.

Mechanical metamaterials are man-made materials which derive their unusual properties from their structure rather than their composition.

PhD Defence

Balikh Valley Archaeological Project Monograph 1 - BAR International Series 468

Large-scale excavations at Neumark-Nord 2 (Germany), a very rich Middle Palaeolithic site with excellent preservation of organic (faunal and floral) remains and lithics in fine-grained lake deposits, dating to about 125,000 years ago.

Report on the Excavations of the University of Amsterdam (1988) and the National Museum of Antiquities Leiden (1991-1993) in Syria.

Lecture, Com(parative) Syn(tax) Series

Surface plasmons (SPs) are surface waves at the interface between a dielectric and a good metal, and are formed by the interaction between light and the free electrons at the metal-dielectric interface. They provide strong field confinement for optical fields, opening new possibilities for enhanced…

PhD Defence

Promotor: H.J.M. de Groot

The thesis mainly contributes to the characterization of Majorana fermions as they appear in the Condensed Matter context.

Are you a non-Dutch national and will you soon be employed by Leiden University?

The HARVEST project explores the dietary choices that our hominin ancestors and relatives made, by recovering information on what they consumed, and how factors like environmental variation, intrinsic biology, and development of food processing technologies could have influenced their decisions.

PhD Defence

Promotor: Prof.dr. J. Zaanen, A. Parnachev

Promotor: Prof.dr.ir. T.H. Oosterkamp, N. de Jonge

Promotor: C. W. J. Beenakker, Yu. V. Nazarov, Co-promotor: J. Tworzydlo

Peak Performance: Collaborative Crisis Management Before and During International Summits. This comparative case study probes into conditions for collaborative governance in the security organisation of international summits.

Rembrandt painted this Flora, the Roman goddess of spring, in 1635. She is on display above the archway leading from the Academy Building to the lush flora of the University’s Hortus Botanicus. Rembrandt, who had his own cabinet of curiosities, almost certainly knew this botanical garden, the oldest…

Identification and characterization of components of DNA repair pathways and their role in Agrobacterium T-DNA integration and repair of CRISPR/Cas induced DSBs.

This thesis contains results on the arithmetic and geometry of del Pezzo surfaces of degree 1.In Chapter 1 we give the necessary background, assuming the reader is familiar with algebraic geometry.

Knowledge and culture subproject 3: "Visual arts and geometry" of Leiden University Centre for Linguistics

Prof. Robbert Dijkgraaf used experiments and models from Leiden University for his tv lecture on symmetry. The lecture was broadcast live on channel 1. He showed that our DNA only twists in one direction using a plastic DNA model and he used a Chladni plate to show the symmetry of sound.

Knowledge and culture subproject 4: "Poetry, rhythm, and meter" of Leiden University Centre for Linguistics

Plants that are pollinated by fewer species of animal may be less vulnerable to change than was thought. This is what Saskia Klumpers discovered in the Rocky Mountains in Colorado. She will be awarded a PhD on 15 December.

Sander Blok has won the third edition of the annual LION Image Award. He created a colorful image of gold nanoparticles with a low-energy electron microscope.

Het project heeft plaats gevonden in de QMO groep onder begeleiding van Dr. Michiel de Dood en Dr.ir. Sense Jan van der Molen. De titel van de presentatie is:

Dive into the heart of archaeological science: explore the flora and fauna of bygone ages, study human bones and teeth, analyse the cultural biographies of material objects, or become an expert in the use of digital data in archaeological research.

Greenhouse gasses in the atmosphere and fertilizers in the groundwater have negative consequences for our environment. With an electrochemical process they can be transformed to more valuable and useful substances like fuel and alcohol. Chemistry PhD candidate Elena Perez Gallent discovered how this…

An international group of scientists, led by Leiden physicist Sense Jan van der Molen, has developed the first switchable molecular diode. You can turn this on and off through humidity. Vice versa, it is a humidity sensor at the nanoscale. Publication on 4 December in Nature Nanotechnology.

The documentary Einstein’s Light by director Nickolas Barris shows in a dazzling manner what scientific breakthroughs resulted from the special friendship between Albert Einstein and the Leiden physicist Hendrik Antoon Lorentz. The documentary premiered at the Leiden International Film Festival on 2…

If three or more objects move around each other, history cannot be reversed. That is the conclusion of an international team of researchers based on computer simulations of three black holes orbiting each other. The researchers, led by the Dutch astronomer Tjarda Boekholt, publish their findings in…

Publication in Proceedings of the National Academy of Sciences.

Knowledge and culture subproject 3: "Visual arts and geometry" of Leiden University Centre for Linguistics

Former PhD, Bachelor and Master students of the Van Exter Lab

Quasicrystals are crystals with ‘impossible’ five-fold symmetries, which nevertheless were synthesized in the lab in 1982. Paul J. Steinhardt helped figure out their structure, but he didn’t stop at that.

Dutch speedskaters have been winning the most medals in speed skating at the Winter Olympics for years. How? Based on their intuition. Scientist Jeroen van der Eb of the Data Mining & Sports group of the Leiden Institute of Advanced Computer Science (LIACS) wants speedskaters to adjust their irons based…

Lecture

The channel through which two cell components exchange material appears to form at the edge of their contact surface, and not in the middle. This was discovered by the Leiden physical chemists Jelger Risselada and Edgar Blokhuis together with researchers from the University of Lausanne in Switzerland.…

Theoretical physicists research a special class of particles; Weyl fermions. They have found them to exhibit paradoxical behavior, in contradiction to a thirty-year old fundamental theory in electromagnetism. A possible application is a new kind of electronics—spintronics. Publication in Physical Review…

Lecture