Body temperature measurement in mice during acute illness: implantable temperature transponder versus surface infrared thermometry

Body temperature is a valuable parameter in determining the wellbeing of laboratory animals. However, using body temperature to refine humane endpoints during acute illness generally lacks comprehensiveness and exposes to inter-observer bias. Here we compared two methods to assess body temperature in mice, namely implanted radio frequency identification (RFID) temperature transponders (method 1) to non-contact infrared thermometry (method 2) in 435 mice for up to 7 days during normothermia and lipopolysaccharide (LPS) endotoxin-induced hypothermia. There was excellent agreement between core and surface temperature as determined by method 1 and 2, respectively, whereas the intra-and inter-subject variation was higher for method 2. Nevertheless, using machine learning algorithms to determine temperature-based endpoints both methods had excellent accuracy in predicting death as an outcome event. Therefore, less expensive and cumbersome non-contact infrared thermometry can serve as a reliable alternative for implantable transponder-based systems for hypothermic responses, although requiring standardization between experimenters

Assessing spatial learning and memory in mice: Classic radial maze versus a new animal-friendly automated radial maze allowing free access and not requiring food deprivation

The radial arm maze (RAM) is a common behavioral test to quantify spatial learning and memory in rodents. Prior attempts to refine the standard experimental setup have been insufficient. Previously, we demonstrated the feasibility of a fully automated, voluntary, and stress-free eight-arm RAM not requiring food or water deprivation. Here, we compared this newly developed refined RAM to a classic manual experimental setup using 24 female 10–12 weeks old C57BL/6J mice. We used a lipopolysaccharide (LPS)-induced model of systemic inflammation to examine long-term cognitive impairment for up to 13 weeks following LPS injection. Both mazes demonstrated robust spatial learning performance during the working memory paradigm. The refined RAM detected spatial learning and memory deficits among LPS-treated mice in the working memory paradigm, whereas the classic RAM detected spatial learning and memory deficits only in the combined working/reference memory paradigm. In addition, the refined RAM allowed for quantification of an animal’s overall exploratory behavior and day/night activity pattern. While our study highlights important aspects of refinement of the new setup, our comparison of methods suggests that both RAMs have their respective merits depending on experimental requirements.Peer Reviewe

Effects of fish predation on density and size spectra of prey fish communities in lakes

Planktivorous and benthivorous fish have been documented to influence the density and size structure of their prey communities in lakes. We hypothesized that piscivorous fish modify their prey fish communities in the same way and sought to find evidence for such predation effects from a comparison across 356 lakes located in nine European ecoregions. We categorized individual fish as being either piscivore, non-piscivore or prey of piscivores, depending on species and individual size. We calculated piscivore, non-piscivore and piscivore prey densities, respectively, and fit linear abundance size spectra (SS) on lake-specific piscivore, non-piscivore and piscivore prey size distributions. Multiple linear regressions were calculated to quantify the effect of piscivore density and SS slopes on non-piscivore and piscivore prey densities and SS slopes, by accounting for potentially confounding factors arising from lake morphometry, productivity and local air temperature. Piscivore density correlated positively with piscivore prey density, but was uncorrelated to density of non-piscivores. Across a subset of 76 lakes for which SS slopes of piscivores were statistically significant, SS slopes of piscivores were uncorrelated with SS slopes of either non-piscivores or piscivore prey. However, densities of piscivores, non-piscivores or piscivore prey were a significant negative predictor of SS slopes of the respective groups. Our analyses suggest that direct predation effects by piscivorous fish on density and size structure of prey fish communities are weak in European lakes, likely caused by low predator-prey size ratios and the resulting size refuges for prey fish. In contrast, competition may substantially contribute to between-lake variability in fish density and size

Knowledge Management als Dienstleistung in einem virtuellen Netzwerk aus dezentral organisierter Technologietransferstellen und Wirtschaftsunternehmen

Innovative Produkt- und Verfahrensentwicklungen sowie die Einführung neuer Technologien setzen insbesondere für Existenzgründer sowie kleine- und mittlere Unternehmen (KmU) firmenübergreifende Kommunikation und Kooperation voraus. Weil insbesondere diesen Unternehmen häufig der Kontakt zu externen Partnern fehlt, sind sie auf die Leistungsangebote von Technologietransferstellen bei der Vermittlung von Informationen und Kontakten zur Umsetzung aus der Forschung abgeleiteter und in der betrieblichen Praxis eingesetzter Produktionsverfahren und -technologien angewiesen. Diese als Intermediäre agierenden Akteure können aufgrund ihrer Wissensbasis relevante Informationen selektieren und dem Nutzer zielgerecht zur Verfügung stellen. Hiermit bieten Sie einen Vorteil gegenüber WZ93-klassifikationsbasierten oder analogen Verzeichniseinträgen und Recherchedatenbanken, die darüber hinaus eine Qualifizierung der erhaltenen Informationen nicht leisten können. In diesem Beitrag werden aufbauend auf einer Darstellung der Problemstellung im Technologietransfer speziell für Existenzgründer sowie KmU, die Anforderungen eines dezentral organisierten Technologietransfer-Netzwerks an einen virtuellen Technologieatlas als Wissensbasis und KM-Instrument vorgestellt. Nachfolgend werden bestehende Konzepte virtueller Technologieatlasse hinsichtlich ihrer Eignung zur Problemlösung entsprechend den vorliegenden Anforderungen der Transferstellen aus der Beispielregion HELLWEG evaluiert. Abschließend wird das entwickelte Konzept für einen virtuellen Technologieatlas hinsichtlich zugrunde liegender technologischer, inhaltlicher und verfahrenstechnischer Merkmale vorgestellt und in Bezug auf zu erreichende Nutzeneffekte bewertet

Refining Humane Endpoints in Mouse Models of Disease by Systematic Review and Machine Learning-Based Endpoint Definition

Ideally, humane endpoints allow for early termination of experiments by minimizing an animal’s discomfort, distress and pain, while ensuring that scientific objectives are reached. Yet, lack of commonly agreed methodology and heterogeneity of cut-off values published in the literature remain a challenge to the accurate determination and application of humane endpoints. With the aim to synthesize and appraise existing humane endpoint definitions for commonly used physiological parameters, we conducted a systematic review of mouse studies of acute and chronic disease models, which used body weight, temperature and/or sickness scores for endpoint definition. In the second part of the study, we used previously published and unpublished data on weight, temperature and sickness scores from mouse models of sepsis and stroke and applied machine learning algorithms to assess the usefulness of this method for parameter selection and endpoint definition across models. Studies were searched for in two electronic databases (MEDLINE/Pubmed and Embase). Out of 110 retrieved full-text manuscripts, 34 studies were included. We found large intra- and inter-model variance in humane endpoint determination and application due to varying animal models, lack of standardized experimental protocols and heterogeneity of performance metrics (part 1). Machine learning models trained with physiological data and sickness severity score or modified DeSimoni neuroscore identified animals with a high risk of death at an early time point in both mouse models of stroke (male: 93.2% at 72h post-treatment; female: 93.0% at 48h post-treatment) and sepsis (96.2% at 24h post-treatment), thus demonstrating generalizability in endpoint determination across models (part 2)

Gauge Orbit Types for Theories with Classical Compact Gauge Group

We determine the orbit types of the action of the group of local gauge transformations on the space of connections in a principal bundle with structure group O(n), SO(n) or $Sp(n)$ over a closed, simply connected manifold of dimension 4. Complemented with earlier results on U(n) and SU(n) this completes the classification of the orbit types for all classical compact gauge groups over such space-time manifolds. On the way we derive the classification of principal bundles with structure group SO(n) over these manifolds and the Howe subgroups of SO(n).Comment: 57 page

Moyal star product approach to the Bohr-Sommerfeld approximation

The Bohr-Sommerfeld approximation to the eigenvalues of a one-dimensional quantum Hamiltonian is derived through order $\hbar^2$ (i.e., including the first correction term beyond the usual result) by means of the Moyal star product. The Hamiltonian need only have a Weyl transform (or symbol) that is a power series in $\hbar$, starting with $\hbar^0$, with a generic fixed point in phase space. The Hamiltonian is not restricted to the kinetic-plus-potential form. The method involves transforming the Hamiltonian to a normal form, in which it becomes a function of the harmonic oscillator Hamiltonian. Diagrammatic and other techniques with potential applications to other normal form problems are presented for manipulating higher order terms in the Moyal series.Comment: 27 pages, no figure

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

Fish assemblages in European lakes

Fischgemeinschaften in Seen sind zunehmenden Umweltveränderungen unterworfen. Die Analyse des Einflusses abiotischer und biotischer Faktoren auf die Größenstruktur von Fischgemeinschaften ist entscheidend, um die Entwicklung von Seeökosystemen im Zuge von Umweltveränderungen vorhersagen zu können. Es ist jedoch schwierig Fische in Seen zu beproben, da Fanggeräte selektiv sind. Die Qualität und Vergleichbarkeit von Fischfängen durch Angler, Kiemennetze, Schleppnetze und Hydroakustik wurden untersucht. Anglerfänge eignen sich begrenzt für vergleichende Fischbestandsuntersuchungen. Vertikale Hydroakustik eignet sich für die Fischbiomassequantifizierung in geschichteten Seen. Der Beprobungsaufwand von Kiemennetzen kann reduziert werden, wenn zeitnah hydroakustische Untersuchungen statt finden. Schleppnetze eignen sich für die Beprobung von pelagischen Fischen in tiefen Seen. Die Größenstruktur von Fischgemeinschaften unterschied sich auf regionaler und überregionaler Ebene entlang abiotischer und biotischer Gradienten. Die regionale Studie zeigte, dass tiefe nährstoffarme Seen mit hohen Raubfischabundanzen durch mehr große Fische gekennzeichnet waren. Nährstoffreiche Flachseen mit wenigen Raubfischen zeigten höhere Anteile von mittleren Fischgrößen. Im überregionalen Vergleich führten Temperaturpräferenzen der Fischarten zu zwei Fischgemeinschaften, die sich in ihrer Größenzusammensetzung unterschieden. Ein hoher Anteil großer Salmoniden war typisch für hochgelegene Kaltwasserseen im Norden und Süden Europas. Flachlandseen mit Kühl- und Warmwasserfischen zeichneten sich durch eine Dominanz von kleinen Fischen aus. Das lässt vermuten, dass Fischgemeinschaften in Flachlandseen relativ robust gegenüber Umweltveränderungen reagieren. Kaltwasserfischgemeinschaften könnten im Zuge der Klimaerwärmung starken Änderungen unterliegen, da eine Veränderung in der Artenzusammensetzung von einer Verschiebung in der Größenstruktur hin zu mehr kleinen Fischen begleitet sein wird.Lake fish assemblages are increasingly exposed to environmental change in their habitats. The investigation of abiotic and biotic factors and their effects on the size structure of lake fish is essential for predicting the response of fish assemblages to environmental change. However, sampling of lake fish is challenging because sampling gears are selective. The quality and correspondence of fish catches from angling, gillnetting, trawling and hydroacoustics were analysed. Non-standardised catch data from recreational angling were of limited quality for a comparison of fish stocks. Vertical hydroacoustics is an efficient method to quantify fish biomass in stratified lakes. Sampling effort of multi-mesh gillnets can be reduced when fish abundance estimates are derived from contemporarily operating hydroacoustics. Trawling is useful to sample pelagic fish assemblages in deep lakes. The size structures of fish assemblages differed on a small and a large geographical scale along gradients of abiotic and biotic lake descriptors and differences in fish assemblage composition. At a small geographical scale assemblages in deep and less nutrient-rich lakes with high predator abundances were characterised by a higher proportion of large fish. Shallow nutrient-rich lakes with few predators were characterised by more medium-sized fish. At a large geographical scale thermal optima of fish generated two types of assemblages with different size structures. A high proportion of large salmonids was observed in coldwater lakes at high elevation sites in northern and southern Europe. Lowland lakes with cool- and warmwater fish were dominated by small-sized individuals. The results suggest that lowland lake fish assemblages are relatively robust against environmental change. Coldwater fish assemblages instead may suffer dramatic consequences from global warming as expected species shifts are likely to be accompanied by shifts in the size structure towards smaller individuals