Sökresultat

Since the start of 2022, 100 million people worldwide have been forced to flee their homes and seek refuge in distant countries. This number reflects the increased displacement within Europe following the invasion of Ukraine in February 2022 but also highlights the ongoing nature of forced migration as people from across the world need to seek asylum and refugee often moving across perilous land a

Fire smoke is one of the most important factors causing casualties, but also has the potential to bring some harm to the surrounding environment. In this work, the longitudinal temperature profile and the pollutant toxicity of a ceiling jet induced by a wall-attached fire with different tunnel slopes, were numerically and experimentally investigated by using a 1:8 reduced-scale inclined tunnel. Th

Dynamical response of water exposed to x-rays is of utmost importance in a wealth of science areas. We exposed isolated water isotopologues to short x-ray pulses from a free-electron laser and detected momenta of all produced ions in coincidence. By combining experimental results and theoretical modeling, we identify significant structural dynamics with characteristic isotope effects in H2O2+, D2O

In this study we derive analytically the equilibrium melting probabilities for basepairs of a DNA molecule with a defect site. We assume that the defect is characterized by a change in the Watson-Crick basepair energy of the defect basepair, and in the associated two stacking energies for the defect, as compared to the remaining parts of the DNA. The defect site could, for instance, occur due to D

Free-electron lasers provide bright, ultrashort, and monochromatic x-ray pulses, enabling novel spectroscopic measurements not only with femtosecond temporal resolution: The high fluence of their x-ray pulses can also easily enter the regime of the non-linear x-ray-matter interaction. Entering this regime necessitates a rigorous analysis and reliable prediction of the relevant non-linear processes

Context. Galaxies are expected to accrete pristine gas from their surroundings to sustain their star formation over cosmic timescales. This mechanism is well established in models and simulations, but evidence from observations is mostly indirect. These gas inflows leave distinct traces in the chemical composition of newborn stars and alter the distribution of stellar abundances compared to what w

As stellar compositions evolve over time in the Milky Way, so will the resulting planet populations. In order to place planet formation in the context of Galactic chemical evolution, we made use of a large (N = 5325) stellar sample representing the thin and thick discs, defined chemically, and the halo, and we simulated planet formation by pebble accretion around these stars. We built a chemical m

Using only linearly polarized light, we study the possibility of generating spin-polarized photoelectrons from xenon atoms. No net spin polarization is possible, since the xenon ground state is spinless, but when the photoelectrons are measured in coincidence with the residual ion, spin polarization emerges. Furthermore, we show that ultrafast dynamics of the recolliding photoelectrons contribute

This chapter aims to encourage tourism researchers to widen their scope of method when studying tourist behavior. It does so by debating tracking mobility and planning exercises as meaningful complements in researchers’ method repertoire. Both methods have been found to reflect tourist behavior in a more accurate way than do, for example, surveys and interviews, which rather mirror what tourists s

Site-selective probing of iodine 4d orbitals at 13.1 nm was used to characterize the photolysis of CH2I2 and CH2BrI initiated at 202.5 nm. Time-dependent fragment ion momenta were recorded using Coulomb explosion imaging mass spectrometry and used to determine the structural dynamics of the dissociating molecules. Correlations between these fragment momenta, as well as the onset times of electron

We present new maps of the Milky Way disk showing the distribution of metallicity ([Fe/H]), α-element abundances ([Mg/Fe]), and stellar age, using a sample of 66,496 red giant stars from the final data release (DR17) of the Apache Point Observatory Galactic Evolution Experiment survey. We measure radial and vertical gradients, quantify the distribution functions for age and metallicity, and explor

For methanol/diesel dual-fuel combustion, there are two different methanol injection implementations: port injection into the intake manifold and direct injection into cylinder. In this work, an experimental comparison was conducted for the two methanol injection strategies to study the effects of the methanol-energy-substation ratio (ESR) and diesel injection timing on the fuel-air mixing and com

We propose a single-shot, high-repetition rate measurement scheme of the carrier-envelope phase offset of ultrashort laser pulses. The spectral fringes resulting from f-2f nonlinear interferometry, encoding the carrier-envelope-phase, are evaluated completely optically via an optical Fourier transform. For demonstration, the carrier-envelope-phase of a 200 kHz, few-cycle optical parametric chirped

The main scientific goal of TESS is to find planets smaller than Neptune around stars that are bright enough to allow for further characterization studies. Given our current instrumentation and detection biases, M dwarfs are prime targets in the search for small planets that are in (or near) the habitable zone of their host star. In this work, we use photometric observations and CARMENES radial ve