Bose-glass phases of ultracold atoms due to cavity backaction

We determine the quantum ground-state properties of ultracold bosonic atoms interacting with the mode of a high-finesse resonator. The atoms are confined by an external optical lattice, whose period is incommensurate with the cavity mode wave length, and are driven by a transverse laser, which is resonant with the cavity mode. While for pointlike atoms photon scattering into the cavity is suppressed, for sufficiently strong lasers quantum fluctuations can support the build-up of an intracavity field, which in turn amplifies quantum fluctuations. The dynamics is described by a Bose-Hubbard model where the coefficients due to the cavity field depend on the atomic density at all lattice sites. Quantum Monte Carlo simulations and mean-field calculations show that for large parameter regions cavity backaction forces the atoms into clusters with a checkerboard density distribution. Here, the ground state lacks superfluidity and possesses finite compressibility, typical of a Bose-glass. This system constitutes a novel setting where quantum fluctuations give rise to effects usually associated with disorder.Comment: 5 pages, 3 figures, new numerical simulations are adde

Can feedback analysis be used to uncover the physical origin of climate sensitivity and efficacy differences?

Different strengths and types of radiative forcings cause variations in the climate sensitivities and efficacies. To relate these changes to their physical origin, this study tests whether a feedback analysis is a suitable approach. For this end, we apply the partial radiative perturbation method. Combining the forward and backward calculation turns out to be indispensable to ensure the additivity of feedbacks and to yield a closed forcing-feedbackbalance at top of the atmosphere

Expression mesenchymaler Stammzell-Marker auf Sarkomen

Diese Arbeit liefert eine Vielzahl an Daten für ein funktionelles Expressionsmuster von neuen MSC-Markern auf Sarkomen, MSCs und Fibroblasten. Verschiedene co-exprimierte spezifische MSC-Marker sind wahrscheinlich nicht spezifisch für Weichteilsarkome. Um das Expressionsprofil im primären Tumorgewebe (Rhabdomyosarkom, Leiomyosarkom und Liposarkom) darzustellen, wurde die Immunhistochemie (IHC) gewählt, in der sich eine Bindung des primären Antikörpers in einer Färbereaktion zeigt. Zur Einordnung einer spezifischen Färbung dienten zusätzlich Positiv- und Negativkontrollen in Form eines Multi tissue-Blocks (Haut, glatte Muskulatur, Fett und Mamma Karzinom) und einer Hämatoxylin-Eosin-Färbung des jeweiligen Gewebes. Aufgrund der in der Arbeitsgruppe erstellten FACS-Daten der Sarkome, mesenchymalen Stammzellen und Vorhautfibroblasten wurden acht Antikörper ausgewählt, um sie weiter an primärem Sarkomgewebe mittels IHC zu erproben. Eine Immunphänotypisierung durch ein einheitliches Differenzierungsmuster gestaltet sich bei den Weichteilsarkomen bedingt durch die verschiedenen Sarkomtypen erschwert. Zusammenfassend ist eine hohe interindividuelle Varianz der Antigenexpression festzustellen. Hierdurch bedingt kam es bei den IHC-Färbungen kaum zu einem homogenen Färbemuster durch die Antikörper. Ein Grundverständnis des Expressionsprofils in Weichteilsarkomen würde eventuell verbesserte Behandlungsmöglichkeiten implizieren, so wie bereits bei der Leukämie (22). Zur Unterstützung der Tumorstammzellen-Hypothese, bei der eine Zellsubpopulation zur Aufrechterhaltung des Tumors führt (24), wäre die Identifikation verschiedener spezifischer Sarkom-Marker essentiell. Die Vermutung, dass Sarkome aus MCSs entstehen, wird stark unterstützt (14-17). Die Tatsache, dass alle hier getesteten Antikörper sowohl auf mesenchymalen Stammzellen, als auch auf embryonalen und adulten Fibroblasten Färbungen zeigen, zeigt, dass es sich um eine große Fibroblasten Familie handelt (26). Trotzdem scheinen manche Marker, die sich sowohl mesenchymale Stammzellen, als auch Sarkome teilen, spezifischer für maligne Zellen verglichen mit den Fibroblasten: TNAP, CD271, W5C5 und CD344 zu sein (1). Die IHC-Färbemuster im Zytoplasma präsentierten sich oft inhomogen innerhalb einer Sarkomgruppe, welches die Hypothese einer Subpopulation unterstreicht. Die Expression von W5C5, TNAP und CD271 zeigte Subpopulationen mit hohem Proliferationspotential auf, was wiederum auf eine potentielle Hierarchie in Sarkomzellen schließen lässt (1). SUDS2 wird mit hoher Wahrscheinlichkeit spezifisch in Gefäßen angefärbt. W3D5A9 färbte mit mittlerer Intensität in der IHC das Mammakarzinom an. Perspektivisch könnte eine fortführende Validierung des Expressionsprofils ausgehend von einer Subpopulation mit einer höheren primären Tumorprobenzahl mittels IHC-Färbung vergleichend mit FACS-Analyse unter Einbeziehung des klinischen Verlaufes interessant sein. Eventuell könnten Rückschlüsse bezüglich einer hoch politerativen Subpopulation und die Vorhersage des Krankheitsverlaufes gezogen werden

TransClim (v1.0): a chemistry–climate response model for assessing the effect of mitigation strategies for road traffic on ozone

Road traffic emits not only carbon dioxide (CO2) and particulate matter, but also other pollutants such as nitrogen oxides (NOx), volatile organic compounds (VOCs) and carbon monoxide (CO). These chemical species influence the atmospheric chemistry and produce ozone (O3) in the troposphere. Ozone acts as a greenhouse gas and thus contributes to anthropogenic global warming. Technological trends and political decisions can help to reduce the O3 effect of road traffic emissions on climate. In order to assess the O3 response of such mitigation options on climate, we developed a chemistry–climate response model called TransClim (Modelling the effect of surface Transportation on Climate). The current version considers road traffic emissions of NOx, VOC and CO and determines the O3 change and its corresponding stratosphere-adjusted radiative forcing. Using a tagging method, TransClim is further able to quantify the contribution of road traffic emissions to the O3 concentration. Thus, TransClim determines the contribution to O3 as well as the change in total tropospheric O3 of a road traffic emission scenario. Both quantities are essential when assessing mitigation strategies. The response model is based on lookup tables which are generated by a set of emission variation simulations performed with the global chemistry–climate model EMAC (ECHAM5 v5.3.02, MESSy v2.53.0). Evaluating TransClim against independent EMAC simulations reveals low deviations of all considered species (0.01 %–10 %). Hence, TransClim is able to reproduce the results of an EMAC simulation very well. Moreover, TransClim is about 6000 times faster in computing the climate effect of an emission scenario than the complex chemistry–climate model. This makes TransClim a suitable tool to efficiently assess the climate effect of a broad range of mitigation options for road traffic or to analyse uncertainty ranges by employing Monte Carlo simulations

Canine vaccination in Germany: A survey of owner attitudes and compliance

Background: Vaccination is the most important preventive measure for protection against infectious diseases in humans and companion animals. Nevertheless, scepticism about the safety and importance of vaccines is increasing in human and in veterinary medicine. Although owner attitudes towards vaccination have been investigated in cats, there are no similar studies in dogs. The goals of this study were therefore to investigate the vaccination status of dogs in Germany, to determine owner compliance with vaccination and to identify factors that play a role in owners' decisions to have their dogs vaccinated. Methods Data were collected from August 2018 to February 2019 using an online survey targeting dog owners in Germany. A total of 3,881 questionnaires were evaluated, and factors associated with the vaccination status of dogs were determined by a linear logistic regression model using Akaike information criterion. Cohen's kappa statistic was used to evaluate agreement between questionnaire and 340 vaccination passports submitted voluntarily by owners. Results: A total of 46.8% (n = 1,818/3,881) of dogs were vaccinated with core vaccines according to current guidelines with the lowest vaccination rate for leptospirosis (50.1%;n = 1,941/3,874). Dog's age (16 weeks to 15 months) (odds ratio (OR): 3.08;95% CI: 2.05-4.68), type (working dog) (OR: 2.06;95% CI: 1.22-3.53) and travelling abroad within previous 36 months (OR: 1.82;95% CI: 1.12-2.96) had the strongest 'positive' association with the vaccination status. Recommendation from a veterinarian not to vaccinate against leptospirosis had the strongest 'negative' association (OR: 0.08;95% CI: 0.04-0.18). Conclusion The study revealed a need for improvement in vaccination compliance because of inadequate vaccination coverage, especially for leptospirosis, in dogs. Factors influencing owner compliance were numerous. Vaccination recommendations made by the veterinarian had a strong association with the vaccination status and should be used to increase canine vaccination rates

Off-Equilibrium Dynamics in Finite-Dimensional Spin Glass Models

The low temperature dynamics of the two- and three-dimensional Ising spin glass model with Gaussian couplings is investigated via extensive Monte Carlo simulations. We find an algebraic decay of the remanent magnetization. For the autocorrelation function $C(t,t_w)=[]_{av}$ a typical aging scenario with a $t/t_w$ scaling is established. Investigating spatial correlations we find an algebraic growth law $\xi(t_w)\sim t_w^{\alpha(T)}$ of the average domain size. The spatial correlation function $G(r,t_w)=[< S_i(t_w)S_{i+r}(t_w)>^2]_{av}$ scales with $r/\xi(t_w)$. The sensitivity of the correlations in the spin glass phase with respect to temperature changes is examined by calculating a time dependent overlap length. In the two dimensional model we examine domain growth with a new method: First we determine the exact ground states of the various samples (of system sizes up to $100\times 100$) and then we calculate the correlations between this state and the states generated during a Monte Carlo simulation.Comment: 38 pages, RevTeX, 14 postscript figure

Using network-flow techniques to solve an optimization problem from surface-physics

The solid-on-solid model provides a commonly used framework for the description of surfaces. In the last years it has been extended in order to investigate the effect of defects in the bulk on the roughness of the surface. The determination of the ground state of this model leads to a combinatorial problem, which is reduced to an uncapacitated, convex minimum-circulation problem. We will show that the successive shortest path algorithm solves the problem in polynomial time.Comment: 8 Pages LaTeX, using Elsevier preprint style (macros included

Displacement Effects of Conservation Grazing on Red Deer (Cervus elaphus) Spatial Behaviour

Conservation grazing uses semi-feral or domesticated herbivores to limit encroachment in open areas and to promote biodiversity. However, we are still unaware of its effects on wild herbivores. This study investigates the influence of herded sheep and goats on red deer (Cervus elaphus) spatial behavior by testing three a-priori hypotheses: (i) red deer are expected to avoid areas used by livestock, as well as adjacent areas, when livestock are present, albeit (ii) red deer increase the use of these areas when sheep and goats are temporarily absent and (iii) there is a time-lagged disruption in red deer spatial behavior when conservation grazing practice ends. Using GPS-telemetry data on red deer from a German heathland area, we modelled their use of areas grazed by sheep and goats, using mixed-effect logistic regression. Additionally, we developed seasonal resource selection functions (use-availability design) to depict habitat selection by red deer before, during, and after conservation grazing. Red deer used areas less during conservation grazing throughout all times of the day and there was no compensatory use during nighttime. This effect mostly persisted within 21 days after conservation grazing. Effects on habitat selection of red deer were detectable up to 3000 meters away from the conservation grazing sites, with no signs of either habituation or adaption. For the first time, we demonstrate that conservation grazing can affect the spatio-temporal behavior of wild herbivores. Our findings are relevant for optimizing landscape and wildlife management when conservation grazing is used in areas where wild herbivores are present.publishedVersio

The critical exponents of the two-dimensional Ising spin glass revisited: Exact Ground State Calculations and Monte Carlo Simulations

The critical exponents for $T\to0$ of the two-dimensional Ising spin glass model with Gaussian couplings are determined with the help of exact ground states for system sizes up to $L=50$ and by a Monte Carlo study of a pseudo-ferromagnetic order parameter. We obtain: for the stiffness exponent $y(=\theta)=-0.281\pm0.002$, for the magnetic exponent $\delta=1.48 \pm 0.01$ and for the chaos exponent $\zeta=1.05\pm0.05$. From Monte Carlo simulations we get the thermal exponent $\nu=3.6\pm0.2$. The scaling prediction $y=-1/\nu$ is fulfilled within the error bars, whereas there is a disagreement with the relation $y=1-\delta$.Comment: 8 pages RevTeX, 7 eps-figures include

Feedback Analyses of Equilibrium Climate Change Simulations

Performing equilibrium climate change simulations is a standard method to study the forcing-response relationship within the climate system. An important finding is th different climate models simulate a considerably different global mean response to the same kind of forcing, and previous studies have focussed to explore the respective reason. Radiative feedbacks are essential in controlling the global response and a model's distinctive climate sensitivity. The cloud feedback has been identified to be of particular importance. Respective evidence in equilibrium simulations is valid for transient model simulations as well. Another key issue is to explain the distinctive global mean response of one and the same model to the same amount of forcing induced by different forcings mechanisms. This so-called efficacy characterising a certain forcing can also be related to the specific acting of feedbacks, and not necessarily to the cloud feedback only. Several ways to explore different efficacy of different forcings have been developed, and it is not clear which method is best suited for the purpose. In this talk we will point out some merits and shortcomings of the "partial radiative perturbation method". It has been applied to equilibrium climate change simulations with a coupled chemistry-climate model. The particular focus will be on CO2 increase simulations