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1. Understanding and explaining the structure of communities in response to environmental gradients is a central goal in ecology. Trait‐based approaches are promising but yet rarely applied to understand community dynamics in response to changing environmental conditions.
2. Here, we investigate seasonal succession patterns of functional traits in phytoplankton communities and how nutrient reductions (oligotrophication) alter these patterns. We used phytoplankton data from 40 years of observation from the Rappbode Reservoir (Germany), which underwent a strong shift in trophic conditions, and translated taxonomic composition into functional traits by assigning trait values compiled from the literature.
3. All studied traits (morphological, behavioural and physiological traits) responded to changing environmental conditions and showed consistent, reoccurring seasonal developments. The seasonal succession of phytoplankton communities was shaped by a trade‐off between small‐celled, fast‐growing species that are able to rapidly incorporate existing resources (r ‐strategists) and large‐celled species with more complex and efficient mechanisms to exploit scarce mineral nutrients or acquire previously unexploited nutrient pools (k ‐strategists). In summer, when nutrients were scarce, the k ‐strategy was prevailing (important traits: phosphate affinity, nitrogen fixation, motility and mixotrophy). During the rest of the year, nutrients and turbulence were high and r ‐strategists dominated (important traits: maximum growth rate and light affinity).
4. A comparison between eutrophic and oligotrophic years revealed that the main features of functional trait succession were largely preserved, but intra‐annual fluctuations from spring to summer were stronger during eutrophic years. Nutrient reductions mainly affected functional traits and biomass in spring, while in summer the functional community composition changed little.
5. Synthesis. This study provides for the first time a quantitatively supported functional template for trait‐based succession patterns in lakes under different nutrient conditions. By translating taxonomic composition into trait information, we demonstrate that the quantification of functional characteristics enables ecological interpretation of observed community dynamics and provides not only a testable template but also a powerful tool towards a more mechanistic understanding. The quantification of functional traits further improves the predictability of community shifts in response to changing environmental conditions and thus opens new perspectives for predictive limnology using lake ecosystem models.
Background
Vertigo, dizziness and balance disorders (VDB) are among the most relevant contributors to the burden of disability among older adults living in the community and associated with immobility, limitations of activities of daily living and decreased participation. The aim of this study was to identify the quality of evidence of physical therapy interventions that address mobility and participation in older patients with VDB and to characterize the used primary and secondary outcomes.
Methods
A systematic search via MEDLINE (PubMed), Cochrane Library, CINAHL, PEDro, forward citation tracing and hand search was conducted initially in 11/2017 and updated in 7/2019. We included individual and cluster-randomized controlled trials and trials with quasi-experimental design, published between 2007 and 2017/2019 and including individuals ≥65 years with VDB. Physical therapy and related interventions were reviewed with no restrictions to outcome measurement. Screening of titles, abstracts and full texts, data extraction and critical appraisal was conducted by two independent researchers. The included studies were heterogeneous in terms of interventions and outcome measures. Therefore, a narrative synthesis was conducted.
Results
A total of 20 randomized and 2 non-randomized controlled trials with 1876 patients met the inclusion criteria. The included studies were heterogeneous in terms of complexity of interventions, outcome measures and methodological quality. Vestibular rehabilitation (VR) was examined in twelve studies, computer-assisted VR (CAVR) in five, Tai Chi as VR (TCVR) in three, canal repositioning manoeuvres (CRM) in one and manual therapy (MT) in one study. Mixed effects were found regarding body structure/function and activities/participation. Quality of life and/or falls were assessed, with no differences between groups. VR is with moderate quality of evidence superior to usual care to improve balance, mobility and symptoms.
Conclusion
To treat older individuals with VDB, VR in any variation and in addition to CRMs seems to be effective. High-quality randomized trials need to be conducted to inform clinical decision making.
Trial registration
PROSPERO 2017 CRD42017080291.
Aquifers are typically perceived as rather stable habitats, characterized by low biogeochemical and microbial community dynamics. Upon contamination, aquifers shift to a perturbed ecological status, in which specialized populations of contaminant degraders establish and mediate aquifer restoration. However, the ecological controls of such degrader populations, and possible feedbacks between hydraulic and microbial habitat components, remain poorly understood. Here, we provide evidence of such couplings, via 4 years of annual sampling of groundwater and sediments across a high-resolution depth-transect of a hydrocarbon plume. Specialized anaerobic degrader populations are known to be established at the reactive fringes of the plume. Here, we show that fluctuations of the groundwater table were paralleled by pronounced dynamics of biogeochemical processes, pollutant degradation, and plume microbiota. Importantly, a switching in maximal relative abundance between dominant degrader populations within the Desulfobulbaceae and Desulfosporosinus spp. was observed after hydraulic dynamics. Thus, functional redundancy amongst anaerobic hydrocarbon degraders could have been relevant in sustaining biodegradation processes after hydraulic fluctuations. These findings contribute to an improved ecological perspective of contaminant plumes as a dynamic microbial habitat, with implications for both monitoring and remediation strategies in situ.
Holzbasierte Bioökonomie
(2020)
Die holzbasierte Bioökonomie beschreibt die innovative Nutzung des Rohstoffs Holz in allen Bereichen der Bioökonomie. Insbesondere versteht sie sich als strategisch altbekannter, aber vor allem als erweiterter, neuartiger Innovationsraum einer Kreislaufwirtschaft mit der gesamten Wertschöpfungskette Holz. Diese erfolgt idealerweise in Form einer sogenannten Nutzungskaskade: vom Forst über die forstlichen Dienstleister, die Sägeindustrie, den Holzbau, die Zellstoff-/Papierindustrie, die Holzwerkstoffindustrie und in zunehmendem Maße bis hin zur chemischen Industrie sowie hinein in moderne Verbrauchs- und Investitionsgüter. Die Nutzungskaskade betrifft damit den gesamten Wirtschaftskreislauf im Kern. Anders als im bisherigen, skalenökonomisch determinierten Wirtschaftsraum muss die Bioökonomie die begrenzte Verfügbarkeit von Ressourcen in Betracht ziehen und zielführende Nachhaltigkeitskriterien beachten. Nutzungskonkurrenzen sollen demzufolge durch intelligente, wertige Verwendung der jeweiligen Holz-, Restholz- und Abfallsortimente weitgehend vermieden werden, wodurch ein tatsächlich sinnvoller Gesamtnutzen für die Gesellschaft möglich erscheint. Um die Bioökonomie umzusetzen und wirtschaftlich zu etablieren, gibt es eine Reihe europäischer, nationaler und regionaler Politikprogramme, Initiativen und Strukturen, die die Forschung und Entwicklung, die Förderung industrieller Umsetzungen und die Etablierung neuer Geschäftsmodelle zum Ziel haben. Deutsche Hochschulen und Universitäten stellen sich auf die entsprechende Erweiterung bzw. Anpassung von Studiengängen ein.
The use of wood in geotechnical applications has seen renewed interest. However, concerns related to the durability and service life of wood in ground contact applications remain. Wood has the potential to substitute commonly used steel and concrete in the geotechnical engineering sector, but solutions to extending the service life and maintenance intervals require long-lasting wood protection systems capable of inhibiting fungal and bacterial decay. Cement, one of the constituents of concrete was identified as a potential coating material for wood used in soil stabilisation works. Spruce and beech wood rest rolls from commercial veneer peeling has been identified as a potential source for cement-coated geotechnical wood products. Norway spruce and European beech wood was subsequently used in this study.
In this study, a series of tests related to dimensional stability and fungal durability were undertaken to investigate the adhesion of a cement coating to wood and to assess the effect of a cement coating on the resistance to fungal decay. Swelling and shrinkage tests of uncoated specimens were undertaken to investigate dimensional stability. Laboratory fungal durability tests assessed changes in wood durability of specimens coated with a novel, flexural cement coating. Wood impregnated with Polyethyleneglycol-dimethacrylate (PEGDMA) prior to cement coating was investigated to improve wood dimensional stability and reduce cracking of the cement coating under changing wood moisture conditions. Cement coating thickness and delamination tests then assessed the durability of the novel cement coating itself. Results from fungal durability tests showed that a continuous, flexural, and crack-free cement coating was imperative to a wood durability improvement. Double cement-coated spruce wood showed improved resistance to decay by basidiomycetes (Coniphora puteana and Trametes versicolor). Results from swelling and shrinkage tests showed that an improvement in dimensional stability would assist in achieving a durable cement coating and impregnation with Polyethyleneglycol-dimethacrylate (PEGDMA) is one manner to improve dimensional stability and therefore cement adhesion to the wood substrate.
Driving forest machines on wet soils causes irreversible soil compaction, often associated with intensive rut formation and inaccessibility of wheeled forest machines for future forest operations. The German forestry equipment manufacturer FHS, Forsttechnik Handel & Service GmbH, engineered a forwarder, the Trac 81/11, equipped with conventional, well-proved bogie-axles embraced by a closed rubber track. At the center of the bogie-axle, four additional supportive rollers are placed to increase the load-carrying section between the tires of the bogie-axle. The study aimed to characterize the principle concept and the trafficability of the forwarder by analyzing the footprint area, the contact pressure, the rut formation on forest sites and the slippage during driving. Therefore, the effective contact area was measured on steel plates and rut formation was analyzed on a case study basis. Results showed that the supportive rollers increase the contact surface area by about 1/3. By this, a decrease of peak loads below the wheels and a more homogenous load distribution were observed. However, the contact surface area is still clearly divided into three parts; the area between the supportive rollers and the wheels does not take any load. Results of the rut formation were diverse: After 20 passes with 26,700 kg total mass, rut depth varied between 12.6 and 212.5 mm. Overall, the new undercarriage concept of FHS demonstrated a generally positive performance. The engineered forwarder contributes to reduce the environmental impact associated with log extraction.
Modern production facilities are becoming increasingly complex, as companies battle to meet the increasingly customer-specific demands with shorter lead times and higher efficiency. For the employees in the factory, who often bear the brunt of making short-term process decisions, this complexity is becoming unmanageable. The PhD project presented in the following aims to decrease the complexity of modern manufactory facilities by means of artificial intelligence. The focus is on product data analysis and manufactory process planning. Different approaches of artificial intelligence for use in a Self-Adapting Smart System (SASS) are to be investigated.
Many doubts accompany both the resource potential of hardwoods and their softwood substituting potential within its material utilisation. However, as the feedstock demand will rise with more and more wood-based biorefineries entering the market, wood supply security is an increasingly pressing topic. Currently, hardwood flow models are lacking, but are an essential basis for estimating future hardwood supply security. This study investigates the actual hardwood flows in Germany by applying a Material Flow Analysis (MFA). Visualising the results of the MFA for the reference year 2016. The MFA displays 4.44 +/- 0.12 million m³ (fob) recorded fellings in privately-owned forests, 8.60 +/- 0.15 million m³ (fob) recorded fellings in state forests, 9.31 +/- 0.52 million m³ (fob) as unrecorded harvest from forests (i.e. 37% of the total harvest) and 2.65 +/- 0.35 million m³ (fob) unrecorded fellings from non-forest area (11% of total harvest). Of that, almost 30% were used for materials and 70% were used for energy. Consequently, the potential for material use of hardwood in Germany lies beyond its current usage, especially given that good qualities are being used for energy due to actual low material consumer demand. Thus, the MFA assessed the quality and quantity of the German hardwood potential and showed that it offers significant possibilities for value added usage options such as, for example, producing innovative products in biorefineries using degraded high-quality assortments. Due to the low data consistency, heterogeneous datasets for the forest and wood industry sector were calibrated through data reconciliation and error propagation. Additionally, the lack of statistical data for specific wood industry sectors raised a problem, for instance, actual data on private combustion of wood, established hardwood uses, or new innovative products. Severe data issues regarding the German hardwood flow were confirmed.
In dieser Arbeit wurden unterschiedliche Regler für Wohnraumlüftungsanlagen untersucht. Als Bewertungsgrößen wurden die Lüftungswärmeverluste und die kumulierte Grenzwertüberschreitung für CO2 und relative Luftfeuchte verwendet. Dafür wurde in Matlab/Simulink ein Multizonen-Simulationsmodell erstellt. Untersucht wurde ein zentrales, ein dezentrales alternierendes (Pendellüftung) sowie ein nichtalternierendes (Einzelraumlüftung) Lüftungssystem. Jedes der Lüftungssysteme wurde mit konstantem Volumenstrom, einem PI- und einem Fuzzy-Regler (Ausnahme: Pendellüftung) simuliert. Gegenüber einem Lüftungssystem mit konstantem Volumenstrom, kann durch Regelung bei mindestens gleicher Luftqualität der Lüftungswärmeverlust um mindestens ein Drittel reduziert werden.