Promotores: Prof.dr. M. Franx, Prof.dr. P.G. van Dokkum (Yale University)

Large areas of space are filled by molecular clouds that consist of gas and dust grains that are the remnants of dead stars. When these clouds start collapsing, the decreasing temperature and increasing density cause gas particles to start accreting onto dust grain surfaces.

Wetland plants are distinguished from plants of other terrestrial ecosystems by their adaptations to specific habitat stresses, including waterlogged and flooding and the subsequent abundance of phytotoxic compounds.

A dense region of a gaseous and dusty cloud collapses to form a protostar surrounded by a disk and an envelope. This thesis uses both observations and models to study physical and chemical conditions of these protostellar systems which are likely where planets start to form.

Promotor: Prof.dr. P. Hooykaas, Co-promotor: R. Offringa

Sobral

The origin and evolution of galaxies are closely tied to the cyclic feedback processes between stars and the interstellar medium (ISM).

Detecting planets during their formation stages is crucial for understanding the history and diversity of fully developed planetary systems like our own. However, observing young planets directly is challenging because they are often deeply embedded within their host protoplanetary discs, rich in gas…

Plants and soils from natural ecosystems harbor great diversity of soil microorganisms, which could potentially contribute to the sustainability of horticulture. The knowledge about using wild plant species and soil from natural ecosystem to improve the crop health will advance the application of ecological…

Promotor: Prof.dr. H.V.J. Linnartz

Promotor: G.R. de Snoo, Co-promotor: C.J.M. Muster

Trigonostemon Blume is a plant genus in the family Euphorbiaceae comprising 59 species.

Protoplanetary disks are the gas and dust environments where planetary systems form around young stars. Using observations from the Atacama Large Millimeter/submillimeter Array (ALMA) this thesis analyses the gaseous molecular reservoir, using multiple tracers to resolve the 3D structure of protoplanetary…

The plant hormone auxin regulates plant growth and development through polar cell-to-cell transport-generated maxima and minima. PIN FORMED (PIN) auxin efflux carriers determine the direction of this auxin flow through their asymmetric placement on the plasma membrane (PM).

Microbiome composition of the spermosphere and the rhizosphere of wild and modern bean accessions grown in an agricultural and a native soil from Colombia was characterized by metagenomics and cultivation-dependent approaches.

It has been a long-standing mystery how complex biological structures emerge from such seemingly uncoordinated building blocks as cells and tissues, in the presence of only minimal environmental guidance.

This thesis describes how different colours of light affect various aspects of the growth and development of Arabidopsis and tomato plants⁠.

In this thesis, I focused on studying the above- and belowground interactions of J. vulgaris from a plant-soil feedback (hereafter, PSF) perspective. I investigated the temporal variation of negative PSF and examined the effects of root-associated bacteria on plant performance and aboveground herbiv…

Promotor: Prof.dr. P.G.L Klinkhamer, Co-promotor: K. Vrieling

Salicylic acid (SA) is a plant hormone, which is involved in the defense responses to pathogens and to abiotic stress, and in the regulation of plant growth and development.

We showed that constitutive and inducible chemical and morphological defenses against Western flower thrips differ between tomato and chrysanthemum plants.

What are trait-trait relationships in wetlands? To what extent the so-called leaf economics traits deviate from terrestrial ecosystems? How traits specific to wetland plant relate to plant strategies? What’s the relationship between wetland plant traits to the ecosystem functioning (e.g. productivity,…

Supervisor: P.J.J. Hooykaas Co-Supervisor: R. Offringa

De Universiteit Leiden biedt astrofysicus Sara Seager een eredoctoraat aan voor haar werk op het gebied van exoplaneten.

This thesis aimed to investigate core cross-linked polymeric micelles (CCPMs) and expand their potential for the delivery of hydrophobic drugs and co-factors.

Multicellular giant algae Chara species have been widely used in physiological studies for decades.

Promotor: G.R. de Snoo, Co-promotor: H.H. de Iongh, C.J.M. Musters

By growing in a soil plants change the biotic and abiotic properties of the soil in which they grow.

Prof.dr. J. Memelink

De NWO heeft een Rubicon-beurs toegekend aan Sara Polak. Per september zal zij 12 maanden onderzoek doen bij het International Graduate Centre for the Study of Culture aan de Justus-Liebig Universität in Giessen, Duitsland.

This thesis takes steps toward understanding the interaction between gas-phase and solid-state molecules in star- and planet-forming regions.

Promotor: Prof.dr. E.F. van Dishoeck, Co-Promotor: M.R. Hogerheijde

This thesis addresses the chemical processes that determine the compositions of giant planet atmospheres.

Sara Polak, PhD-student en docent bij het LUCAS, heeft een Fulbright beurs gewonnen met haar onderzoek naar Franklin D. Roosevelt. Met de beurs gaat per september een half jaar research doen aan Yale University.

This thesis aims to enhance our understanding of galaxies by testing theoretical models of galaxy formation against observations, particularly in the cases of extreme systems which have been found to have an excess of baryonic mass in their central regions, in the form of either supermassive black holes…

My work focuses on a class of astronomical objects called protoplanetary disks.

NU.nl sprak met Amerikanist Sara Polak over de tegenaanval van Trump en de algemene stand zaken in het Ruslandonderzoek:

Promotor: Prof.dr. E.F. van Dishoeck, Co-Promotor: G.J. Herczeg

Een stroom aan nieuwsberichten, pushmeldingen en zelfs extra nieuwsuitzendingen: de wereld werd woensdag opgeschrikt door de bestorming van het Capitool in Washington. Amerikanist Sara Polak reflecteert op de gebeurtenissen.

Amerikaanse president Donald Trump plaatst veel misleidende berichten op Twitter. Toch is het mogelijk dat Trump wederom the presidentsverkiezingen wint. Sara Polak, universitair docent Amerikanistiek, legt in Trouw uit hoe dat kan.

Herstel van de natuur op uitgeputte landbouwgrond en in natuurgebieden verloopt moeizaam. ‘Bodemtransplantatie’ kan mogelijk uitkomst bieden. Dat betoogt Martijn Bezemer, hoogleraar Ecologie van Plant-Microbe-Insect interacties. Oratie op 18 december.

Terwijl ze midden in haar scriptie-onderzoek zit wordt criminologie-student Sara Kalf (24) aangereden en raakt ze zwaargewond. Na lang revalideren en hard werken, zette ze vorige week eindelijk haar handtekening in het Zweetkamertje.

De Amerikaanse president Joe Biden wordt regelmatig vergeleken met zijn voorganger Franklin Roosevelt. Ook zelf maakt hij die vergelijking graag. In de Groene Amsterdammer onderzoekt universitair docent Sara Polak waarop die vergelijking is gebaseerd.

Abortus is lang een relatief klein thema in de Amerikaanse politiek geweest. Dat de uitspraak van het Amerikaans hooggerechtshof nu wereldnieuws is, komt volgens universitair docent Sara Polak door Amerikaanse partijpolitiek. Op De Correspondent gaat ze dieper op het thema in.

De abortuswetgeving in de Verenigde Staten staat op het punt om strenger te worden. In het radioprogramma OVT vertelt universitair docent Sara Polak waarom abortus zo’n belangrijk politiek thema is geworden.

‘Een eerste referendum op Donald Trumps presidentschap’, zo worden de opkomende midterm elections ook wel genoemd. Tijdens deze tussentijdse verkiezingen kunnen Amerikanen hun stem uitbrengen voor verschillende politieke functies. Wat betekent dit voor de Amerikaanse politiek? Sara Polak, universitair…

Plants, are sessile organisms, have developed strategies to adapt to changes in their environment, in part by altering their growth and development.

Na China en Italië, lijken de Verenigde Staten nu het epicentrum van de coronacrisis te worden. Kunnen de VS deze crisis aan? Handelt president Trump juist? We vroegen het Leidse Amerikadeskundige Sara Polak.

This thesis focusses on the temperature structure in protoplanetary disks. The relation between structures seen in the dust and gas-phase molecules is investigated.