Transport and scattering in inhomogeneous quantum wires

We consider scattering and transport in interacting quantum wires that are connected to leads. Such a setup can be represented by a minimal model of interacting fermions with inhomogeneities in the form of sudden changes in interaction strength and/or velocity. The inhomogeneities generally cause relevant backscattering, so it is a priori unclear if a perfectly ballistic quantum wire can exist in the low temperature limit. We are able to identify such a perfectly conducting fixed point even for large abrupt changes, which in the considered model corresponds to a velocity matching condition. The general position dependent Green's function is calculated in the presence of a sudden change, which is confirmed numerically with high accuracy. The exact form of the interference pattern in the form of density oscillations around inhomogeneities can be used to estimate the effective strength of local backscattering sources.Comment: 5 pages, 3 figures. Published version. For more information and the latest version see http://www.physik.uni-kl.de/eggert/papers/index.htm

Routine habitat switching alters the likelihood and persistence of infection with a pathogenic parasite

Animals switch habitats on a regular basis, and when habitats vary in suitability 21 for parasitism, routine habitat switching alters the frequency of parasite exposure 22 and may affect post-infection parasite proliferation. However, the effects of 23 routine habitat switching on infection dynamics are not well understood. 24 2. We performed infection experiments, behavioural observations, and field 25 surveillance to evaluate how routine habitat switching by adult alpine newts 26 (Ichthyosaura alpestris) influences infection dynamics of the pathogenic parasite, 27 Batrachochytrium dendrobatidis (Bd). 28 3. We show that when newts are exposed to equal total doses of Bd in aquatic 29 habitats, differences in exposure frequency and post-exposure habitat alter 30 infection trajectories: newts developed more infections that persisted longer when 31 doses were broken into multiple, reduced-intensity exposures. Intensity and 32 persistence of infections was reduced among newts that were switched to 33 terrestrial habitats following exposure. 34 4. When presented with a choice of habitats, newts did not avoid exposure to Bd, 35 but heavily infected newts were more prone to reduce time spent in water. 36 5. Accounting for routine switching between aquatic and terrestrial habitat in the 37 experiments generated distributions of infection loads that were consistent with 38 those in two populations of wild newts. 39 6. Together, these findings emphasize that differential habitat use and behaviours 40 associated with daily movement can be important ecological determinants of 41 infection risk and severity. 4

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe