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Ultrafast control and opto-optical modulation of extreme ultraviolet light

Ultrashort, coherent light pulses in the extreme ultraviolet (XUV) wavelength region are excellent tools for a wide range of experiments. These XUV pulses are in particular used to characterize electron dynamics. Additionally, the high photon energy enables quantum control of short-lived transitions in atoms. These transitions are of interest for ultrafast quantum control as the bandwidth of the c

Twisted Ribbon Aggregates in a Model Peptide System

The model peptides A 8 K and A 10 K self-assemble in water into ca. 100 nm long ribbon-like aggregates. These structures can be described as β-sheets laminated into a ribbon structure with a constant elliptical cross-section of 4 by 8 nm, where the longer axis corresponds to a finite number, N ≠15, of laminated sheets, and 4 nm corresponds to a stretched peptide length. The ribbon cross-section

Pterin-pigmented nanospheres create the colours of the polymorphic damselfly Ischnura elegans

Animal colours commonly act as signals for mates or predators. In many damselfly species, both sexes go through a developmental colour change as adults, and females often show colour polymorphism, which may have a function in mate choice, avoidance of mating harassment and camouflage. In the blue-tailed damselfly, Ischnura elegans, young males are bright green and turn blue as they reach maturity.

Public Space as Commodity: The Social Production of the Hong Kong Waterfront

While there has been a long tradition of public space related land speculation and development, the recent success of the High Line in New York has highlighted the transformative effect carefully designed and curated public spaces can have on the local economy. By prioritising exchange value over use value, governments and developers are exploiting the production of public spaces as a means for fi

Repeated disturbances affect functional but not compositional resistance and resilience in an aquatic bacterioplankton community

Disturbances are believed to be one of the main factors influencing variations in community diversity and functioning. Here we investigated if exposure to a pH press disturbance affected the composition and functional performance of a bacterial community and its resistance, recovery and resilience to a second press disturbance (salt addition). Lake bacterial assemblages were initially exposed to r

Shifts in coastal sediment oxygenation cause pronounced changes in microbial community composition and associated metabolism

BACKGROUND: A key characteristic of eutrophication in coastal seas is the expansion of hypoxic bottom waters, often referred to as 'dead zones'. One proposed remediation strategy for coastal dead zones in the Baltic Sea is to mix the water column using pump stations, circulating oxygenated water to the sea bottom. Although microbial metabolism in the sediment surface is recognized as key in regula

Local Environmental Conditions Shape Generalist But Not Specialist Components of Microbial Metacommunities in the Baltic Sea

Marine microbes exhibit biogeographical patterns linked with fluxes of matter and energy. Yet, knowledge of the mechanisms shaping bacterioplankton community assembly across temporal scales remains poor. We examined bacterioplankton 16S rRNA gene fragments obtained from Baltic Sea transects to determine phylogenetic relatedness and assembly processes coupled with niche breadth. Communities were ph

Metapopulation theory identifies biogeographical patterns among core and satellite marine bacteria scaling from tens to thousands of kilometers

Metapopulation theory developed in terrestrial ecology provides applicable frameworks for interpreting the role of local and regional processes in shaping species distribution patterns. Yet, empirical testing of metapopulation models on microbial communities is essentially lacking. We determined regional bacterioplankton dynamics from monthly transect sampling in the Baltic Sea Proper using 16S rR

Transplant experiments uncover Baltic Sea basin-specific responses in bacterioplankton community composition and metabolic activities

Anthropogenically induced changes in precipitation are projected to generate increased river runoff to semi-enclosed seas, increasing loads of terrestrial dissolved organic matter and decreasing salinity. To determine how bacterial community structure and functioning adjust to such changes, we designed microcosm transplant experiments with Baltic Proper (salinity 7.2) and Bothnian Sea (salinity 3.

Decadal-scale progression of the onset of Dansgaard-Oeschger warming events

During the last glacial period, proxy records throughout the Northern Hemisphere document a succession of rapid millennial-scale warming events, called Dansgaard-Oeschger (DO) events. A range of different mechanisms has been proposed that can produce similar warming in model experiments; however, the progression and ultimate trigger of the events are still unknown. Because of their fast nature, th

Disentangling seasonal bacterioplankton population dynamics by high-frequency sampling

Multiyear comparisons of bacterioplankton succession reveal that environmental conditions drive community shifts with repeatable patterns between years. However, corresponding insight into bacterioplankton dynamics at a temporal resolution relevant for detailed examination of variation and characteristics of specific populations within years is essentially lacking. During 1 year, we collected 46 s

Evaluation of terrestrial pan-Arctic carbon cycling using a data-assimilation system

There is a significant knowledge gap in the current state of the terrestrial carbon (C) budget. Recent studies have highlighted a poor understanding particularly of C pool transit times and of whether productivity or biomass dominate these biases. The Arctic, accounting for approximately 50% of the global soil organic C stocks, has an important role in the global C cycle. Here, we use the CARbon D

Ultrafast THz Probe of Photoinduced Polarons in Lead-Halide Perovskites

We study the nature of photoexcited charge carriers in CsPbBr3 nanocrystal thin films by ultrafast optical pump-THz probe spectroscopy. We observe a deviation from a pure Drude dispersion of the THz dielectric response that is ascribed to the polaronic nature of carriers; a transient blueshift of observed phonon frequencies is indicative of the coupling between photogenerated charges and stretchin

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