Erdreich : der Schatz unter unseren Füssen

Im neuen Garten «Erdreich» auf dem Campus Grüental werden Besucherinnen und Besucher eingeladen, den Boden als geheimnisvollen Schatz unter unseren Füssen zu erkunden. In Zusammenarbeit verschie­dener Fachleute aus den Bereichen Bodenökologie, Landschaftsarchitektur, Kunst und Kommunikation ist ein ungewöhnlicher Garten entstanden, der die Faszination für die wertvolle Ressource Boden weckt

Disentangling structural and kinetic components of the {\alpha}-relaxation in supercooled metallic liquids

The particle motion associated to the {\alpha}-relaxation in supercooled liquids is still challenging scientists due to its difficulty to be probed experimentally. By combining synchrotron techniques, we found the existence of microscopic structure-dynamics relationships in Pt42.5Cu27Ni9.5P21 and Pd42.5Cu27Ni9.5P21 liquids which allows us to disentangle structural and kinetic contributions to the {\alpha}-process. While the two alloys show similar kinetic fragilities, their structural fragilities differ and correlate with the temperature dependence of the stretching parameter describing the decay of the density fluctuations. This implies that the evolution of dynamical heterogeneities in supercooled alloys is determined by the rigidity of the melt structure. We find also that the atomic motion not only reflects the topological order but also the chemical short-range order, which can lead to a surprising slowdown of the {\alpha}-process at the mesoscopic length scale. These results will contribute to the comprehension of the glass transition, which is still missing

Disentangling structural and kinetic components of the α-relaxation in supercooled metallic liquids

The particle motion associated to the α-relaxation in supercooled liquids is still challenging scientists due to its difficulty to be probed experimentally. By combining synchrotron techniques, we report the existence of microscopic structure-dynamics relationships in Pt42.5Cu27Ni9.5P21 and Pd42.5Cu27Ni9.5P21 liquids which allows us to disentangle structural and kinetic contributions to the α-process. While the two alloys show similar kinetic fragilities, their structural fragilities differ and correlate with the temperature dependence of the stretching parameter describing the decay of the density fluctuations. This implies that the evolution of dynamical heterogeneities in supercooled alloys is determined by the rigidity of the melt structure. We find also that the atomic motion not only reflects the topological order but also the chemical short-range order, which can lead to a surprising slowdown of the αprocess at the mesoscopic length scale. These results will contribute to the comprehension of the glass transition, which is still missing

Untersuchung der Eigenschaften und Fruchtbarkeit von Gewächshausböden

Im Auftrag des Bundesamtes für Umwelt (BAFU)Die Fruchtfolgeflächen in der Schweiz sind unter Druck. Beim Bau von Gewächshäusern stellt sich die Frage, ob diese weiterhin als Fruchtfolgeflächen angerechnet werden könnten oder nicht. Über die Qualität von Gewächshausböden in Abhängigkeit vom Anbausystem gibt es nur wenige Daten. Um für diese Diskussion und allfällige Entscheide eine Datengrundlage zu schaffen, sollen im vorliegenden Projekt die Qualität unterschiedlich genutzter Gewächshausböden untersucht werden. Der Fokus liegt auf folgenden Forschungsfragen: Inwieweit beeinflussen der Bau und Betrieb von Gewächshäusern die betroffenen Böden? Welche Rolle spielt die Bewirtschaftungsart? Unter welchen Bedingungen erfüllen Gewächshausböden die Kriterien eines fruchtbaren Bodens? Für die Untersuchungen wurden sieben Gewächshäuser (GWH) mit unterschiedlicher Bewirtschaftung ausgewählt: Bodenkultur (BK), Hors-sol (HS) und saisonale Wechsel zwischen Bodenkultur und Hors-sol (W). Auf jeweils drei Plots in den Gewächshäusern und auf ausserhalb der Gewächshäuser liegenden Referenzflächen wurden biologische und physikalische Bodenparameter erhoben und Profilansprachen durchgeführt. Die biologischen Parameter sollen eine Aussage über die biologische Aktivität und die Biodiversität in den Böden ermöglichen, die physikalischen den Einfluss des Baus und der Bewirtschaftung auf die Dichte und den Wasserhaushalt des Bodens untersuchen. Auch das Erfassen chemischer Parameter wurde verzichtet, da in der Diskussion um Fruchtfolgeflächen nicht von zentraler Bedeutung sind. Obwohl die Vergleichbarkeit zwischen Gewächshäusern und Referenzflächen und auch die Einheitlichkeit der Eigenschaften der Gewächshausböden nicht in allen Fällen optimal war, ist es möglich, den Einfluss der Bewirtschaftung auf die Gewächshausböden zu erkennen. Sowohl in den GWH mit BK, als auch in denjenigen mit W sind die Gehalte an organischem Material erhöht, vermutlich wegen der mit den Setzlingen eingebrachten Torfpresslingen. Biologische Parameter wie mikrobielle Biomasse, DNA Menge und Bodenatmung korrelieren üblicherweise stark mir Corg. In den GWH mit BK ist dies der Fall. Bei den GWH W ist die Korrelation aber um einiges weniger stark, als man es erwarten würde. Dies und die Tatsache, dass in den letzteren der metabolische Koeffizient deutlich erhöht war, lässt auf nicht ideale Bedingungen für die Bodenorganismen unter W schliessen. Die Gewächshäuser mit HS weisen die geringsten Gehalte an Corg auf und zeigten auch sonst eine tiefere biologische Aktivität als die übrigen Versuchsflächen. Mithilfe der molekularbiologischen Untersuchungen konnten standortspezifische aber auch gewächshausspezifische Lebensgemeinschaften in den Böden nachgewiesen werden. Generell war der Artenreichtum in den Gewächshausböden tiefer als in den dazugehörigen Referenzflächen. Interessanterweise konnten viele erwünschte oder unerwünschte Zielorganismen neben phytopathogenen auch pflanzenstärkende und bodenbelebende Mikroben nachgewiesen werden. Durch die Messung von bodenphysikalischen Grössen konnten bei allen untersuchten Standorten mit mineralischen Böden in den Gewächshäusern und/oder auf den Referenzflächen mindestens Richtwertüberschreitungen festgestellt werden. Nicht immer ist aber die Beeinträchtigung im Gewächshaus grösser als ausserhalb und die Unterschiede zwischen Gewächshäusern im gleichen Betrieb waren teilweise gross. Ein Vergleich zwischen dem Verdichtungszustand der Böden und den Aussagen der Bewirtschafter zum Gewächshausbau zeigen einen Zusammenhang zwischen nassen Bedingungen beim Bau und Verdichtungen innerhalb und in der Umgebung des Gewächshauses. Bei den untersuchten Gewächshäusern verlangten die Bewilligungsbehörden in keinem Fall eine Bodenkundliche Baubegleitung (BBB). Bezüglich Verdichtung wären klarere Vorgaben für den Ablauf sicher sinnvoll. Die Frage, ob Gewächshauböden grundsätzlich die Kriterien von Fruchtfolgeflächen erfüllen, lässt sich aufgrund unserer kleinen Stichprobe nicht abschliessend beantworten. Weitere Untersuchungen, vor allem bei Gewächshäusern mit Hors-sol oder Wechsel zwischen Hors-sol und Bodenkultur wären interessant. Dazu wäre eine grössere Stichprobe an Gewächshäusern wichtig. Vertiefte Untersuchungen mit molekularbiologischen Methoden könnten zeigen, ob sich die Habitat-Gebundenheit von mikrobiellen Gemeinschaftsstrukturen ausnutzen lässt, um typische Gemeinschaften von "gestörten" oder "geschädigten" zu unterscheiden

Dispersal of harmful fruit fly pests by international trade and a loop-mediated isothermal amplification assay to prevent their introduction

Global trade of plant products represents one of the major driving forces for the spread of invasive insect pests. This visualization illustrates the problem of unintended dispersal of economically harmful fruit fly pests using geospatial maps based on interception data from the Swiss import control process. Furthermore, it reports the development of a molecular diagnostic assay for rapid identification of these pests at points of entry such as sea- and airports as a prevention measure. The assay reliably differentiates between target and non-target species within one hour and has been successfully evaluated for on-site use at a Swiss point of entry

Ecology of Alpine Macrofungi - Combining Historical with Recent Data

Historical datasets of living communities are important because they can be used to document creeping shifts in species compositions. Such a historical data set exists for alpine fungi. From 1941 to 1953, the Swiss geologist Jules Favre visited yearly the region of the Swiss National Park and recorded the occurring fruiting bodies of fungi >1 mm (so-called “macrofungi”) in the alpine zone. Favre can be regarded as one of the pioneers of alpine fungal ecology not least because he noted location, elevation, geology, and associated plants during his numerous excursions. However, some relevant information is only available in his unpublished field-book. Overall, Favre listed 204 fungal species in 26 sampling sites, with 46 species being previously unknown. The analysis of his data revealed that the macrofungi recorded belong to two major ecological groups, either they are symbiotrophs and live in ectomycorrhizal associations with alpine plant hosts, or they are saprotrophs and decompose plant litter and soil organic matter. The most frequent fungi were members of Inocybe and Cortinarius, which form ectomycorrhizas with Dryas octopetala or the dwarf alpine Salix species. The scope of the present study was to combine Favre’s historical dataset with more recent data, either with the “SwissFungi” database or with data from major studies of the French and German Alps, and with the data from novel high-throughput DNA sequencing techniques of soils from the Swiss Alps. Results of the latter application revealed, that problems associated with these new techniques are manifold and species determination remains often unclear. At this point, the fungal taxa collected by Favre and deposited as exsiccata at the “Conservatoire et Jardin Botaniques de la Ville de Genève” could be used as a reference sequence dataset for alpine fungal studies. In conclusion, it can be postulated that new improved databases are urgently necessary for the near future, particularly, with regard to investigating fungal communities from alpine regions using new techniques

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Evolutionary Relationships of Wild Hominids Recapitulated by Gut Microbial Communities

Although bacteria are continually acquired over the lifetime of an individual, the phylogenetic relationships of great ape species is mirrored in the compositions of their gut microbial communities

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication