@article{14016, abstract = {All attosecond time-resolved measurements have so far relied on the use of intense near-infrared laser pulses. In particular, attosecond streaking, laser-induced electron diffraction and high-harmonic generation all make use of non-perturbative light–matter interactions. Remarkably, the effect of the strong laser field on the studied sample has often been neglected in previous studies. Here we use high-harmonic spectroscopy to measure laser-induced modifications of the electronic structure of molecules. We study high-harmonic spectra of spatially oriented CH3F and CH3Br as generic examples of polar polyatomic molecules. We accurately measure intensity ratios of even and odd-harmonic orders, and of the emission from aligned and unaligned molecules. We show that these robust observables reveal a substantial modification of the molecular electronic structure by the external laser field. Our insights offer new challenges and opportunities for a range of emerging strong-field attosecond spectroscopies.}, author = {Kraus, P. M. and Tolstikhin, O. I. and Baykusheva, Denitsa Rangelova and Rupenyan, A. and Schneider, J. and Bisgaard, C. Z. and Morishita, T. and Jensen, F. and Madsen, L. B. and Wörner, H. J.}, issn = {2041-1723}, journal = {Nature Communications}, keywords = {General Physics and Astronomy, General Biochemistry, Genetics and Molecular Biology, General Chemistry, Multidisciplinary}, publisher = {Springer Nature}, title = {{Observation of laser-induced electronic structure in oriented polyatomic molecules}}, doi = {10.1038/ncomms8039}, volume = {6}, year = {2015}, } @article{14013, abstract = {The ultrafast motion of electrons and holes after light-matter interaction is fundamental to a broad range of chemical and biophysical processes. We advanced high-harmonic spectroscopy to resolve spatially and temporally the migration of an electron hole immediately after ionization of iodoacetylene while simultaneously demonstrating extensive control over the process. A multidimensional approach, based on the measurement and accurate theoretical description of both even and odd harmonic orders, enabled us to reconstruct both quantum amplitudes and phases of the electronic states with a resolution of ~100 attoseconds. We separately reconstructed quasi-field-free and laser-controlled charge migration as a function of the spatial orientation of the molecule and determined the shape of the hole created by ionization. Our technique opens the prospect of laser control over electronic primary processes.}, author = {Kraus, P. M. and Mignolet, B. and Baykusheva, Denitsa Rangelova and Rupenyan, A. and Horný, L. and Penka, E. F. and Grassi, G. and Tolstikhin, O. I. and Schneider, J. and Jensen, F. and Madsen, L. B. and Bandrauk, A. D. and Remacle, F. and Wörner, H. J.}, issn = {1095-9203}, journal = {Science}, keywords = {Multidisciplinary}, number = {6262}, pages = {790--795}, publisher = {American Association for the Advancement of Science}, title = {{Measurement and laser control of attosecond charge migration in ionized iodoacetylene}}, doi = {10.1126/science.aab2160}, volume = {350}, year = {2015}, } @article{14015, abstract = {We advance high-harmonic spectroscopy to resolve molecular charge migration in time and space and simultaneously demonstrate extensive control over the process. A multidimensional approach enables us to reconstruct both quantum amplitudes and phases with a resolution of better than 100 attoseconds and to separately reconstruct field-free and laser- driven charge migration. Our techniques make charge migration in molecules measurable on the attosecond time scale and open new avenues for laser control of electronic primary processes.}, author = {Kraus, P M and Mignolet, B and Baykusheva, Denitsa Rangelova and Rupenyan, A and Horný, L and Penka, E F and Tolstikhin, O I and Schneider, J and Jensen, F and Madsen, L B and Bandrauk, A D and Remacle, F and Wörner, H J}, issn = {1742-6596}, journal = {Journal of Physics: Conference Series}, keywords = {General Physics and Astronomy}, number = {11}, publisher = {IOP Publishing}, title = {{Attosecond charge migration and its laser control}}, doi = {10.1088/1742-6596/635/11/112136}, volume = {635}, year = {2015}, } @article{14014, abstract = {We have studied a coupled electronic-nuclear wave packet in nitric oxide using time-resolved strong-field photoelectron holography and rescattering. We show that the electronic dynamics mainly appears in the holographic structures whereas nuclear motion strongly modulates the angular distribution of the rescattered photoelectrons.}, author = {Walt, Samuel G and Ram, N Bhargava and von Conta, Aaron and Baykusheva, Denitsa Rangelova and Atala, Marcos and Wörner, Hans Jakob}, issn = {1742-6596}, journal = {Journal of Physics: Conference Series}, keywords = {General Physics and Astronomy}, number = {11}, publisher = {IOP Publishing}, title = {{Resolving the dynamics of valence-shell electrons and nuclei through laser-induced diffraction and holography}}, doi = {10.1088/1742-6596/635/11/112135}, volume = {635}, year = {2015}, } @misc{9719, abstract = {Parasitism creates selection for resistance mechanisms in host populations and is hypothesized to promote increased host evolvability. However, the influence of these traits on host evolution when parasites are no longer present is unclear. We used experimental evolution and whole-genome sequencing of Escherichia coli to determine the effects of past and present exposure to parasitic viruses (phages) on the spread of mutator alleles, resistance, and bacterial competitive fitness. We found that mutator alleles spread rapidly during adaptation to any of four different phage species, and this pattern was even more pronounced with multiple phages present simultaneously. However, hypermutability did not detectably accelerate adaptation in the absence of phages and recovery of fitness costs associated with resistance. Several lineages evolved phage resistance through elevated mucoidy, and during subsequent evolution in phage-free conditions they rapidly reverted to nonmucoid, phage-susceptible phenotypes. Genome sequencing revealed that this phenotypic reversion was achieved by additional genetic changes rather than by genotypic reversion of the initial resistance mutations. Insertion sequence (IS) elements played a key role in both the acquisition of resistance and adaptation in the absence of parasites; unlike single nucleotide polymorphisms, IS insertions were not more frequent in mutator lineages. Our results provide a genetic explanation for rapid reversion of mucoidy, a phenotype observed in other bacterial species including human pathogens. Moreover, this demonstrates that the types of genetic change underlying adaptation to fitness costs, and consequently the impact of evolvability mechanisms such as increased point-mutation rates, depend critically on the mechanism of resistance.}, author = {Wielgoss, Sébastien and Bergmiller, Tobias and Bischofberger, Anna M. and Hall, Alex R.}, publisher = {Dryad}, title = {{Data from: Adaptation to parasites and costs of parasite resistance in mutator and non-mutator bacteria}}, doi = {10.5061/dryad.cj910}, year = {2015}, }