Supersolidity in Two-Dimensional Trapped Dipolar Droplet Arrays.

We theoretically investigate the ground states and the spectrum of elementary excitations across the superfluid to droplet crystallization transition of an oblate dipolar Bose-Einstein condensate. We systematically identify regimes where spontaneous rotational symmetry breaking leads to the emergence of a supersolid phase with characteristic collective excitations, such as the Higgs amplitude mode. Furthermore, we study the dynamics across the transition and show how these supersolids can be realized with standard protocols in state-of-the-art experiments.

Roton Excitations in an Oblate Dipolar Quantum Gas.

We observe signatures of radial and angular roton excitations around a droplet crystallization transition in dipolar Bose-Einstein condensates. In situ measurements are used to characterize the density fluctuations near this transition. The static structure factor is extracted and used to identify the radial and angular roton excitations by their characteristic symmetries. These fluctuations peak as a function of the interaction strength indicating the crystallization transition of the system. We compare our observations to a theoretically calculated excitation spectrum allowing us to connect the crystallization mechanism with the softening of the angular roton modes.

Fate of the Amplitude Mode in a Trapped Dipolar Supersolid.

We theoretically investigate the spectrum of elementary excitations of a trapped dipolar quantum gas across the BEC-supersolid phase transition. Our calculations reveal the existence of distinct Higgs amplitude and Nambu-Goldstone modes that emerge from the softening roton modes of the dipolar BEC at the phase transition point. On the supersolid side of the transition, the energy of the Higgs amplitude mode increases rapidly, leading to a strong coupling to higher-lying modes. Our Letter highlights how the symmetry-breaking nature of the supersolid state translates to finite-size systems.

Observation of Quantum-Limited Spin Transport in Strongly Interacting Two-Dimensional Fermi Gases.

We measure the transport properties of two-dimensional ultracold Fermi gases during transverse demagnetization in a magnetic field gradient. Using a phase-coherent spin-echo sequence, we are able to distinguish bare spin diffusion from the Leggett-Rice effect, in which demagnetization is slowed by the precession of a spin current around the local magnetization. When the two-dimensional scattering length is tuned to be comparable to the inverse Fermi wave vector k_{F}^{-1}, we find that the bare transverse spin diffusivity reaches a minimum of 1.7(6)ℏ/m, where m is the bare particle mass. The rate of demagnetization is also reflected in the growth rate of the s-wave contact, observed using time-resolved spectroscopy. The contact rises to 0.28(3)k_{F}^{2} per particle, which quantifies how scaling symmetry is broken by near-resonant interactions, unlike in unitary three-dimensional systems. Our observations support the conjecture that, in systems with strong scattering, the local relaxation rate is bounded from above by k_{B}T/ℏ.

[Case report: fatal diving-accident. Or: accident while diving?]. / Tödlicher Tauchunfall. Oder: Unfall während des Tauchens mit Todesfolge?

This example of a fatal diving accident shows how challenging such cases can be in pre-hospital and clinical care. There is no common mechanism in diving fatalities and more than one group of disorders coming along with decompression sickness. Diving medicine is not an element of medical education, which results in insecurity and hampers adequate therapy of diving incidents. This is aggravated by an insufficient availability of hyperbaric chambers in Germany.

Extracting strong measurement noise from stochastic time series: applications to empirical data.

It is a big challenge in the analysis of experimental data to disentangle the unavoidable measurement noise from the intrinsic dynamical noise. Here we present a general operational method to extract measurement noise from stochastic time series even in the case when the amplitudes of measurement noise and uncontaminated signal are of the same order of magnitude. Our approach is based on a recently developed method for a nonparametric reconstruction of Langevin processes. Minimizing a proper non-negative function, the procedure is able to correctly extract strong measurement noise and to estimate drift and diffusion coefficients in the Langevin equation describing the evolution of the original uncorrupted signal. As input, the algorithm uses only the two first conditional moments extracted directly from the stochastic series and is therefore suitable for a broad panoply of different signals. To demonstrate the power of the method, we apply the algorithm to synthetic as well as climatological measurement data, namely, the daily North Atlantic Oscillation index, shedding light on the discussion of the nature of its underlying physical processes.

[E-mail in plastic surgery--a useful addition to current communication possibilities?]. / E-mail in der Plastischen Chirurgie--Eine sinnvolle Ergänzung bestehender Kommunikationsmöglichkeiten?

The internet is a global network of computers with a broad variety of services and options. It offers completely new ways of communication and investigation. At present, this new medium seems to be the final technical revolution in communication. It presents new dimensions which were utopia so far. Electronic mail (e-mail) is the most frequently used service within the internet. For a plastic surgeon it seems to be the fastest and the most cost-effective way of transferring data of any kind. The aim of this paper is to critically assess the transfer of confidential data via e-mail as well as to present general conditions for the use of e-mails. Therefore, our own experiences made with this technology are described to point to the possibilities, but also to indicate problems and weaknesses of this medium. Some rules should be obeyed for the transfer of confidential patient data via e-mail in order to satisfy the demand for data-security standards. Also medicolegal aspects must be considered. These recommendations or rules and aspects will be discussed to offer a guideline to plastic surgeons for their e-mail applications.

A set of genetic markers for the chromosomes of the imperfect yeast Arxula adeninivorans.

The nuclear genome of the anamorphic yeast Arxula adeninivorans was analysed by benomyl-induced haploidization of parasexual hybrids marked with 32 auxotrophic mutations and pulsed field gel electrophoresis followed by DNA hybridization. Twenty-seven genes have been arranged into four linkage groups by haploidization, 15 genes belong to group 1, six to group 2, and three each to groups 3 and 4. Five genes could be localized by DNA hybridization on three out of four separated chromosomes. The gene LYS2 of the largest linkage group 1 and the 25S rDNA were identified on the largest chromosome, the GAA and the TEF1 gene on chromosome 2, and the ILV1 gene of linkage group 4 on the smallest chromosome.

Mitotically unstable polyploids in the yeast Pichia guilliermondii.

Attempts to obtain triploids or tetraploids of P. guilliermondii by sexual hybridization led to mitotically stable hybrids. However, their DNA content per cell was not higher than in diploids. The results of random spore analysis demonstrate that these hybrids were in fact aneuploids which obviously suffered drastic chromosome losses immediately after mating. This phenomenon could have been caused either by aneuploidy already present in the parental strains or it might have been due to a general inability of P. guilliermondii to maintain a polyploid genome.

Auxotrophic mutants of the yeast Trichosporon adeninovorans.

We have isolated and characterized auxotrophic mutants of Trichosporon adeninovorans, strain PAR-4 to get genetic markers that cover the entire nuclear genome of this thermotolerant yeast of technological interest. The nitrosoguanidine mutagenesis yielded mutants at a high frequency. We detected a broad spectrum of auxotrophic phenotypes in the random mutant samples. Obviously, strain PAR-4 is a haploid or hyperhaploid yeast. In correspondence we determined a low DNA content per cell. In contrast to NG1), UV light was an inefficient mutagen. UV survival curves were without the typical shoulder indicating suppression of repair of UV-induced lethal lesions. Thus, the response of PAR-4 to UV was different from those of Saccharomyces cerevisiae and other yeasts.

[Gene transfer using fusion of isolated cell nuclei with protoplasts of the yeast Saccharomyces cerevisiae]. / Perenos genov s pomoshch'iu sliianiia izolirovannykh kletochnykh iader s protoplastami drozhzhei Saccharomyces cerevisiae.

Hybrid clones of Saccharomyces cerevisiae with different genotypes have been obtained by polyethyleneglycol induced fusion of isolated cellular nuclei with protoplasts. The genetic instability of complete nuclei after fusion results in formation of different genotypes.

Genetic transfer mediated by isolated nuclei in Saccharomyces cerevisiae.

Viable hybrids of Saccharomyces cerevisiae were obtained by transfer of isolated diploid nuclei into haploid protoplasts using a polyethylene glycol (PEG) fusion procedure.

Genetic control of plastid differentiation. 3 ultrastructure of plastids in different green revertant spots of the plastom mutant Pl-alb1 of Lycopersicon esculentum.

Reverse mutations in plastid DNA give rise to phenotypically different green spots on the white tissues of the homoplastic plastom mutant Pl-alb1. The structure of the plastids in one yellow-green, one green and one dark-green spot, each arising by independent reverse mutation, was studied by means of electron microscopy. Although the same revertant plastid types (type 1 with a weakly developed lamellar system; type 2 with vacuolized grana, and type 3 with a wild type-like structure were found in all three spots, variations in separation of Pl-alb1 and revertant plastids, and in the predominant revertant plastid type, were observed among the spots investigated. The revertant plastids of different phenotype occurred not only within one spot, but also within one cell. An hypothesis explaining this phenomenon is suggested.