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    Surface Preparation and Treatment for Large-Scale 3D-Printed Composite Tooling Coating Adhesion 

    Sauerbier, Philipp; Anderson, James; Gardner, Douglas
    Coatings 2018; 8(12): Art. 457
    Recent advances in large-scale thermoplastic additive manufacturing (AM), using fused deposition modelling (FDM), have shown that the technology can effectively produce large aerospace tools with common feed stocks, costing 2.3 $/kg, such as a 20% carbon-filled acrylonitrile butadiene styrene (ABS). Large-scale additive manufacturing machines have build-volumes in the range of cubic meters and use commercially available pellet feedstock thermoplastics, which are significantly cheaper (5–10 $/kg) than the filament feedstocks for desktop 3D printers (20–50 $/kg). Additionally, large-scale AM machines have a higher material throughput on the order of 50 kg/h. This enables the cost-efficient tool production for several industries. Large-scale 3D-printed tooling will be computerized numerical control (CNC)-machined and -coated, to provide a surface suitable for demolding the composite parts. This paper outlines research undertaken to review and improve the adhesion of the coating systems to large, low-cost AM composite tooling, for marine or infrastructure composite applications. Lower cost tooling systems typically have a lower dimensional accuracy and thermal operating requirements than might be required for aerospace tooling. As such, they can use lower cost commodity grade thermoplastics. The polymer systems explored in the study included polypropylene (PP), styrene-maleic anhydride (SMA), and polylactic acid (PLA). Bio-based filler materials were used to reduce cost and increase the strength and stiffness of the material. Fillers used in the study included wood flour, at 30% by weight and spray-dried cellulose nano-fibrils, at 20% by weight. Applicable adhesion of the coating was achieved with PP, after surface treatment, and untreated SMA and PLA showed desirable coating adhesion results. PLA wood-filled composites offered the best properties for the desired application and, furthermore, they have environment-friendly advantages
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    A barrier island perspective on species–area relationships 

    Scherber, Christoph; Andert, Hagen; Niedringhaus, Rolf; Tscharntke, Teja
    Ecology and Evolution p.1-11
    Predictions of species richness by island area are a classical cornerstone in ecology, while the specific features of barrier islands have been little appreciated. Many shorelines are occupied by barrier islands, which are shaped by offshore sedimentation processes and annual storm tide events. Hence, the appearance of these islands may vary between years if they are not protected by dykes. Here, we analyzed more than 2,990 species across 36 taxonomic groups (including vertebrates, invertebrates, and land plants) on German barrier islands, the East Frisian Islands. We tested for relationships between species richness or species incidence and island area (SAR), island habitat diversity and further island parameters using a range of generalized linear and mixed‐effects models. Overall species richness was explained best by habitat diversity (Shannon index of habitat types). Analyses on the occurrence probability of individual species showed that changes of barrier island area by sedimentation and erosion, that is, barrier island‐specific dynamics, explained the occurrence of 17 of 34 taxa, including most beetles, plants, and birds. Only six taxa such as spiders (249 species) and mammals (27 species) were primarily related to area. The diversity of habitat types was a key predictor for the incidence of twenty‐five taxa, including ground beetles, true bugs and grasshoppers, amphibians, and reptiles. Overall, richness and incidence of taxa differed greatly in their responses, with area (although varying from 0.1 to 38.9 km2) playing a minor and island heterogeneity a major role, while barrier island‐specific sedimentation and erosion turned out to additionally explain species richness and occurrence.
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    Seasonal dynamics and changing sea level as determinants of the community and trophic structure of oribatid mites in a salt marsh of the Wadden Sea 

    Winter, Marlena; Haynert, Kristin; Scheu, Stefan; Maraun, Mark
    PLOS ONE 2018; 13(11): Art. e0207141
    Global change processes affect seasonal dynamics of salt marshes and thereby their plant and animal communities. However, these changes have been little investigated for microarthropod communities. We studied the effect of seasonality and changes in sea level on oribatid mites in the natural salt marsh and on artificial islands in the back-barrier environment of the island Spiekeroog (Wadden Sea, Germany). Three zones of the artificial islands were filled with transplanted sods from the lower salt marsh zone and thereby exposed to three different inundation frequencies. We hypothesized that oribatid mite communities will differ along the natural salt marsh vegetation zones [upper salt marsh (USM), lower salt marsh (LSM), pioneer zone (PZ)], which are influenced by different tidal regimes. Accordingly, total oribatid mite densities declined from the USM and LSM to the PZ. Similarly, oribatid mite species compositions changed along the salt marsh transect and also responded to variations in inundation frequency in LSM on artificial islands with typical species of the USM, LSM and PZ being Multioppia neglecta (USM), Hermannia pulchella (LSM), Zachvatkinibates quadrivertex (LSM, PZ) and Ameronothrus schneideri (LSM, PZ). Oribatid mite density in the salt marsh and on the artificial islands was at a maximum in winter and spring; this was due in part to high density of juveniles, pointing to two reproductive periods. We hypothesized that oribatid mite trophic structure changes due to variations in abiotic (e.g., tidal dynamics, temperature) and biotic conditions (e.g., resource availability). Stable isotope (15N, 13C) and neutral lipid fatty acid analyses indicated that oribatid mite species have different diets with e.g., Z. quadrivertex feeding on macroalgae and fungi, A. schneideri feeding on microalgae and bacteria, and Scheloribates laevigatus and M. neglecta feeding on dead organic matter, bacteria and fungi. Overall, the results indicate that oribatid mite species in salt marshes are affected by changes in environmental factors such as inundation intensity, with the effects being most pronounced in species with narrow trophic niches and limited niche plasticity. The results also indicate that oribatid mite communities of the LSM respond little to short-term (one year) changes in inundation frequency.
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    Money or smiles: Independent ERP effects of associated monetary reward and happy faces 

    Hammerschmidt, Wiebke; Kulke, Louisa; Broering, Christina; Schacht, Annekathrin
    PLOS ONE 2018; 13(10): Art. e0206142
    n comparison to neutral faces, facial expressions of emotion are known to gain attentional prioritization, mainly demonstrated by means of event-related potentials (ERPs). Recent evidence indicated that such a preferential processing can also be elicited by neutral faces when associated with increased motivational salience via reward. It remains, however, an open question whether impacts of inherent emotional salience and associated motivational salience might be integrated. To this aim, expressions and monetary outcomes were orthogonally combined. Participants (N = 42) learned to explicitly categorize happy and neutral faces as either reward- or zero-outcome-related via an associative learning paradigm. ERP components (P1, N170, EPN, and LPC) were measured throughout the experiment, and separately analyzed before (learning phase) and after (consolidation phase) reaching a pre-defined learning criterion. Happy facial expressions boosted early processing stages, as reflected in enhanced amplitudes of the N170 and EPN, both during learning and consolidation. In contrast, effects of monetary reward became evident only after successful learning and in form of enlarged amplitudes of the LPC, a component linked to higher-order evaluations. Interactions between expressions and associated outcome were absent in all ERP components of interest. The present study provides novel evidence that acquired salience impacts stimulus processing but independent of the effects driven by happy facial expressions.
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    High Morphological Differentiation in Crown Architecture Contrasts with Low Population Genetic Structure of German Norway Spruce Stands 

    Caré, Oliver; Müller, Markus; Vornam, Barbara; Höltken, Aki; Kahlert, Karina; Krutovsky, Konstantin; Gailing, Oliver; Leinemann, Ludger
    Forests 2018; 9(12): Art. 752
    High elevation sites in the low mountain ranges in Germany are naturally covered by Norway spruce (Picea abies (Karst.) L.) stands. Historically, large scale anthropogenic range expansion starting in the mid to late 18th century had a huge impact on the forest composition throughout Germany. Utilisation and exploitation often led to artificial regeneration, mostly carried out using seeds from allochthonous provenances. Usually, autochthonous (natural) high elevation Norway spruce trees have narrow crown phenotypes, whereas lowland trees have broader crowns. Narrow crown phenotypes are likely the result of adaptation to heavy snow loads combined with high wind speeds. In the present study, neighbouring stand pairs of putative autochthonous and allochthonous origin with contrasting phenotypes in high elevation sites were investigated with 200 samples each. These stands are located in the Ore Mountains, the Thuringian Forest, and the Harz Mountains. Additionally, a relict population with the typical narrow high elevation phenotypes was sampled in Thuringia, known as “Schlossbergfichte”. The objective of the study was to quantify supposedly adaptive phenotypic differences in crown architecture and the genetic differentiation of 11 putatively neutral nuclear microsatellite markers (i.e., simple sequence repeats (nSSRs)). The high differentiation of morphological traits (PST = 0.952–0.989) between the neighbouring autochthonous and allochthonous stands of similar age contrasts with the very low neutral genetic differentiation (FST = 0.002–0.007; G″ST = 0.002–0.030), suggesting that directional selection at adaptive gene loci was involved in phenotypic differentiation. Comparing the regions, a small isolation by distance effect for the Harz Mountains was detected, suggesting landscape resistance restricting gene flow. Finally, the differentiation of the very old autochthonous (up to 250 years) stand “Schlossbergfichte” with typical high elevation phenotypes could cohere with the sampling of a relict genepool.
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    The Tragedy of Forestland Sustainability in Postcolonial Africa: Land Development, Cocoa, and Politics in Côte d’Ivoire 

    Ongolo, Symphorien; Kouamé Kouassi, Sylvestre; Chérif, Sadia; Giessen, Lukas
    Sustainability 2018; 10(12): Art. 4611
    Tropical countries are often blamed for not managing their natural resources sustainably. But what if overexploitation is inherent in political structures and policies—rooted in foreign colonial order—and is consistently detrimental in the contemporary use of forestlands? This article argues that post-colonial land development policies and related political interests seriously impede the sustainability of forest ecosystems in Côte d’Ivoire. Methodologically, the study builds on a historic contextualisation of forestland use policies in Sub-Saharan Africa, with Côte d’Ivoire serving as a case study. The results indicate that the increasing development of so-called rent crops clearly follows the historical dynamics of ‘land grabbing’ and a post-colonial agrarian model. This situation benefits agribusiness entrepreneurs and, more recently, sustainability standards. The study discusses the findings based on recent literature and empirical evidence. In conclusion, the post-colonial heritage and the manipulation of the related patterns by elites and policy-makers largely explains the present-day unsustainable forestland conversions in Côte d’Ivoire.
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    Bacterial infections among patients with psychiatric disorders: Relation with hospital stay, age, and psychiatric diagnoses 

    Belz, Michael; Rehling, Nico; Schmidt, Ulrike; Wiltfang, Jens; Kis, Bernhard; Wolff-Menzler, Claus
    PLOS ONE 2018; 13(12): Art. e0208458
    The prevalence of infections is supposed to be higher in older patients and to extend the length of hospital stays. This study aimed, first, to test this supposition within a large psychiatric population which we divided into four clusters of psychiatric ICD-10 diagnoses: F00-F03 (dementias), F10 (substance disorders), F20-29 (schizophrenia, schizophreniform and other non-mood psychotic disorders), F32-F33 (major depressive disorders). Second, despite the increasing evidence for the role of infections in psychiatric disorders, it is, to the best of our knowledge, largely unknown whether the rates of infections with pathogens of the four most frequent germ families differ between psychiatric diseases. Thus, in a retrospective study, the results of clinical routine examinations (pap smear, analysis of midstream urine, stool) dependent on symptoms in 8545 patients of a German psychiatric clinic were analyzed in a 12-year dataset. Results show that a longer hospital stay was associated with an increased number of microbiological tests, but led to no significant difference between positive vs. negative findings. Consistent with previous studies, patients with infections were older than patients without infections. For the F10 diagnosis cluster we found a significantly reduced (F10: Staphylococcaceae) and for the F20-29 cluster a heightened risk of infections (Staphylococcaceae, Corynebacteriaceae). Furthermore, patients belonging to the F00-F03 cluster exhibited elevated rates of infections with all four germ families. The latter can be ascribed to patients' age as we found higher age to be associated with these infections, independently of the presence of dementia. Our results suggest that different psychiatric diagnoses are associated with a heightened or lowered risk of bacterial infections and, furthermore, that clinical routine infection-screenings for elderly psychiatric patients seems to be reasonable.
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    Iron Corrosion: Scientific Heritage in Jeopardy 

    Hu, Rui; Noubactep, Chicgoua
    Sustainability 2018; 10(11): Art. 4138
    Research on the use of metallic iron (Fe0) for environmental remediation and water treatment has taken off during the past three decades. The results achieved have established filtration on Fe0 packed beds as an efficient technology for water remediation at several scales. However, the further development of Fe0-based filtration systems is impaired by the non-professional behavior of scientists who ignore available advances in knowledge. The confusion is overcome when due consideration is given to the fact that revealing state-of-the-art knowledge is a prerequisite to presenting individual achievements.
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    Self-organized stress patterns drive state transitions in actin cortices 

    Tan, Tzer Han; Malik-Garbi, Maya; Abu-Shah, Enas; Li, Junang; Sharma, Abhinav; MacKintosh, Fred C.; Keren, Kinneret; Schmidt, Christoph F.; Fakhri, Nikta
    Science Advances 2018; 4(6): Art. eaar2847
    Biological functions rely on ordered structures and intricately controlled collective dynamics. This order in living systems is typically established and sustained by continuous dissipation of energy. The emergence of collective patterns of motion is unique to nonequilibrium systems and is a manifestation of dynamic steady states. Mechanical resilience of animal cells is largely controlled by the actomyosin cortex. The cortex provides stability but is, at the same time, highly adaptable due to rapid turnover of its components. Dynamic functions involve regulated transitions between different steady states of the cortex. We find that model actomyosin cortices, constructed to maintain turnover, self-organize into distinct nonequilibrium steady states when we vary cross-link density. The feedback between actin network structure and organization of stress-generating myosin motors defines the symmetries of the dynamic steady states. A marginally cross-linked state displays divergence-free long-range flow patterns. Higher cross-link density causes structural symmetry breaking, resulting in a stationary converging flow pattern. We track the flow patterns in the model actomyosin cortices using fluorescent single-walled carbon nanotubes as novel probes. The self-organization of stress patterns we have observed in a model system can have direct implications for biological functions.
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    Does the Optimal Dietary Methionine to Cysteine Ratio in Diets for Growing Chickens Respond to High Inclusion Rates of Insect Meal from Hermetia illucens? 

    Brede, Anne; Wecke, Christian; Liebert, Frank
    Animals 2018; 8(11): Art. 187
    The dietary methionine:cysteine (Met:Cys) ratio (MCR) is an important factor influencing the optimal growth of chickens. Therefore, this study aimed to contribute to the assessment of the optimal dietary MCR in diets with the complete replacement of soybean meal (SBM) by a partly defatted larvae meal of Hermetia illucens (HM). A growth study with 240 male meat-type chickens (Ross 308) was conducted, also assessing the body nutrient deposition both at the end of the starter (day 21) and the grower (day 35) period. Birds were fed experimental diets based on wheat, maize, and insect meal (23%/21% HM in starter/grower diets). Sulfur amino acids were created as the limiting AA in diets with graded MCR (40:60; 45:55; 50:50; 55:45; 60:40). The control diet contained SBM instead of HM with a MCR of 50:50. The current results based on growth parameters, dietary protein quality, and Met efficiency data gave support to the previous assumption of an ideal MCR of 50:50, which was also valid in diets with a high proportion of insect meal. The lowest MCR of 40:60 led to significantly impaired feed intake and growth of the birds, while the response to the highest MCR (60:40) was moderate.
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    Analysis of porcine body size variation using re-sequencing data of miniature and large pigs 

    Reimer, C.; Rubin, C.-J.; Sharifi, A. R.; Ha, N.-T.; Weigend, S.; Waldmann, K.-H.; Distl, O.; Pant, S. D.; Fredholm, M.; Schlather, M.; et al.
    Simianer, H.
    BMC Genomics 2018; 19(1): Art. 687
    BACKGROUND: Domestication has led to substantial phenotypic and genetic variation in domestic animals. In pigs, the size of so called minipigs differs by one order of magnitude compared to breeds of large body size. We used biallelic SNPs identified from re-sequencing data to compare various publicly available wild and domestic populations against two minipig breeds to gain better understanding of the genetic background of the extensive body size variation. We combined two complementary measures, expected heterozygosity and the composite likelihood ratio test implemented in "SweepFinder", to identify signatures of selection in Minipigs. We intersected these sweep regions with a measure of differentiation, namely FST, to remove regions of low variation across pigs. An extraordinary large sweep between 52 and 61 Mb on chromosome X was separately analyzed based on SNP-array data of F2 individuals from a cross of Goettingen Minipigs and large pigs. RESULTS: Selective sweep analysis identified putative sweep regions for growth and subsequent gene annotation provided a comprehensive set of putative candidate genes. A long swept haplotype on chromosome X, descending from the Goettingen Minipig founders was associated with a reduction of adult body length by 3% in F2 cross-breds. CONCLUSION: The resulting set of genes in putative sweep regions implies that the genetic background of body size variation in pigs is polygenic rather than mono- or oligogenic. Identified genes suggest alterations in metabolic functions and a possible insulin resistance to contribute to miniaturization. A size QTL located within the sweep on chromosome X, with an estimated effect of 3% on body length, is comparable to the largest known in pigs or other species. The androgen receptor AR, previously known to influence pig performance and carcass traits, is the most obvious potential candidate gene within this region.
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    Response of Collembola and Acari communities to summer flooding in a grassland plant diversity experiment 

    González-Macé, Odette; Scheu, Stefan
    PLOS ONE 2018; 13(8): Art. e0202862
    Flooding frequency is predicted to increase during the next decades in Europe. Therefore, it is important to understand how short-term disturbance events affect soil biota providing essential ecosystem functions and uncover factors modulating their response such as plant community composition. Here we report on the response of soil microarthropod communities (Collembola and Acari) to a severe summer flood in 2013, which affected major parts of central Europe. Collembola and Acari density and Collembola and Oribatida richness were strongly affected by the flood, but they recovered within three months. Effects of plant community composition on soil microarthropods disappeared after the flood, presumably due to homogenization of the field, but the effects of plant community were in a stage of being reasserted three months after the flood. Widespread, surface living and generalistic microarthropod species recolonized the field quickly. Prostigmata and Oribatida were more resilient or recovered to flooding than Astigmata and Gamasida. Long-term impacts, however, remain unknown and deserve further investigation.
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    Identification and validation of reference genes for qPCR in the terrestrial gastropod Cepaea nemoralis 

    Affenzeller, Susanne; Cerveau, Nicolas; Jackson, Daniel John
    PLOS ONE 2018; 13(8): Art. e0201396
    Identifying and understanding mechanisms that generate phenotypic diversity is a fundamental goal of evolutionary biology. With a diversity of pigmented shell morphotypes governed by Mendelian patterns of inheritance, the common grove snail Cepaea nemoralis (Linnaeus, 1758) has been a model for evolutionary biologists and population geneticists for decades. However, the genetic mechanisms by which C. nemoralis generates this pigmented shell diversity remain unknown. An important first step in investigating this pigmentation pattern is to establish a set of validated reference genes for differential gene expression assays. Here we have evaluated eleven candidate genes for reverse transcription quantitative polymerase chain reaction (qPCR) in C. nemoralis. Five of these were housekeeping genes traditionally employed as qPCR reference genes in other species, while six alternative genes were selected de novo from C. nemoralis transcriptome data based on the stability of their expression levels. We tested all eleven candidates for expression stability in four sub-adult tissues of C. nemoralis: pigmented mantle, unpigmented mantle, head and foot. We find that two commonly employed housekeeping genes (alpha tubulin, glyceraldehyde 3-phosphate dehydrogenase) are unsuitable for use as qPCR reference genes in C. nemoralis. The traditional housekeeping gene UBIquitin on the other hand performed very well. Additionally, an RNAdirected DNA polymerase (RNAP), a Potassium Channel Protein (KCHP) and a Prenylated Rab acceptor protein 1 (PRAP), identified de novo from transcriptomic data, were the most stably expressed genes in different tissue combinations. We also tested expression stability over two seasons and found that, although other genes are more stable within a single season, beta actin (BACT) and elongation factor 1 alpha (EF1α) were the most reliable reference genes across seasons.
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    Using imaging photoplethysmography for heart rate estimation in non-human primates 

    Unakafov, Anton M.; Möller, Sebastian; Kagan, Igor; Gail, Alexander; Treue, Stefan; Wolf, Fred
    PLOS ONE 2018; 13(8): Art. e0202581
    For humans and for non-human primates heart rate is a reliable indicator of an individual's current physiological state, with applications ranging from health checks to experimental studies of cognitive and emotional state. In humans, changes in the optical properties of the skin tissue correlated with cardiac cycles (imaging photoplethysmogram, iPPG) allow noncontact estimation of heart rate by its proxy, pulse rate. Yet, there is no established simple and non-invasive technique for pulse rate measurements in awake and behaving animals. Using iPPG, we here demonstrate that pulse rate in rhesus monkeys can be accurately estimated from facial videos. We computed iPPGs from eight color facial videos of four awake head-stabilized rhesus monkeys. Pulse rate estimated from iPPGs was in good agreement with reference data from a contact pulse-oximeter: the error of pulse rate estimation was below 5% of the individual average pulse rate in 83% of the epochs; the error was below 10% for 98% of the epochs. We conclude that iPPG allows non-invasive and non-contact estimation of pulse rate in non-human primates, which is useful for physiological studies and can be used toward welfare-assessment of non-human primates in research.
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    Analysis of Energy Dissipation Channels in a Benchmark System of Activated Dissociation: N2 on Ru(0001). 

    Shakouri, Khosrow; Behler, Jörg; Meyer, Jörg; Kroes, Geert-Jan
    The Journal of Physical Chemistry. C, Nanomaterials and Interfaces 2018; 122(41) p.23470-23480
    The excitation of electron-hole pairs in reactive scattering of molecules at metal surfaces often affects the physical and dynamical observables of interest, including the reaction probability. Here, we study the influence of electron-hole pair excitation on the dissociative chemisorption of N2 on Ru(0001) using the local density friction approximation method. The effect of surface atom motion has also been taken into account by a high-dimensional neural network potential. Our nonadiabatic molecular dynamics simulations with electronic friction show that the reaction of N2 is more strongly affected by the energy transfer to surface phonons than by the energy loss to electron-hole pairs. The discrepancy between the computed reaction probabilities and experimental results is within the experimental error both with and without friction; however, the incorporation of electron-hole pairs yields somewhat better agreement with experiments, especially at high collision energies. We also calculate the vibrational efficacy for the N2 + Ru(0001) reaction and demonstrate that the N2 reaction is more enhanced by exciting the molecular vibrations than by adding an equivalent amount of energy into translation.
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    Functional diversity changes over 100 yr of primary succession on a volcanic island: insights into assembly processes 

    Karadimou, E.; Kallimanis, A. S.; Tsiripidis, I.; Raus, T.; Bergmeier, E.; Dimopoulos, P.
    Ecosphere 2018; 9(9): Art. e02374
    Changes in species diversity following volcanic eruptions have been studied extensively, but our knowledge on functional diversity and community assembly under such conditions is very limited. Here, we study the processes following the destruction of vegetation after a volcanic eruption. Specifically, we investigate (1) the temporal patterns of taxonomic and functional diversity over time since a previous eruption (alpha diversity) and beta diversity, (2) the temporal patterns of 26 individual traits (vegetative characteristics, plant taxa ecological preferences, and regenerative characteristics) providing more detailed information on species strategies at the initial and later stages of succession, and (3) the processes driving species assembly and whether they changed over time since the eruption an eruption. We analyzed data recorded during five floristic censuses that took place between 1911 and 2011, calculated alpha and beta facets of taxonomic and functional diversity and examined how community structure changed over time, using 26 functional characteristics, based on their ability to discern primary from later colonists, including longevity, growth form, Ellenberg’s indicator values, seed production and weight, flower size and sex, pollination type, and dispersal mode. Null model analysis was used to test whether the observed functional diversity deviates from random expectations. Alpha diversity, both taxonomic and functional, increased over time after an eruption, while beta diversity did not display a clear trend. This finding indicates that mainly abiotic processes determine species assembly over time after an eruption (at least for the time span studied here), contrary to theoretical expectations. It is most interesting that, simultaneously, some aspects of diversity indicated the effect of biotic interactions (facilitation and competition) on the assembly of species a few years after an eruption. This finding implies a legacy effect, since a high percentage of perennial species was noticed in the assemblage right after the eruption, as well as the effect of the harsh environmental conditions on the assembly of the plant communities. In conclusion, our results indicate the role of legacy effects in succession (most probably through the survival of underground plant parts) and underline the importance of disturbance history in providing the context needed for understanding effects of past events on succession.
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    Conceptual model development using a generic Features, Events, and Processes (FEP) database for assessing the potential impact of hydraulic fracturing on groundwater aquifers 

    Tatomir, Alexandru; McDermott, Christopher; Bensabat, Jacob; Class, Holger; Edlmann, Katriona; Taherdangkoo, Reza; Sauter, Martin
    Advances in Geosciences 2018; 45 p.185-192
    Hydraulic fracturing for natural gas extraction from unconventional reservoirs has not only impacted the global energy landscape but has also raised concerns over its potential environmental impacts. The concept of “features, events and processes” (FEP) refers to identifying and selecting the most relevant factors for safety assessment studies. In the context of hydraulic fracturing we constructed a comprehensive FEP database and applied it to six key focused scenarios defined under the scope of FracRisk project (http://www.fracrisk.eu, last access: 17 August 2018). The FEP database is ranked to show the relevance of each item in the FEP list per scenario. The main goal of the work is to illustrate the FEP database applicability to develop a conceptual model for regional-scale stray gas migration.
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    Diffusion limitations and Michaelis–Menten kinetics as drivers of combined temperature and moisture effects on carbon fluxes of mineral soils 

    Moyano, Fernando Esteban; Vasilyeva, Nadezda; Menichetti, Lorenzo
    Biogeosciences 2018; 15(16) p.5031-5045
    CO2 production in soils responds strongly to changes in temperature and moisture, but the magnitude of such responses at different timescales remains difficult to predict. Knowledge of the mechanisms leading to the often observed interactions in the effects of these drivers on soil CO2 emissions is especially limited. Here we test the ability of different soil carbon models to simulate responses measured in soils incubated at a range of moisture levels and cycled through 5, 20, and 35 C. We applied parameter optimization methods while modifying two structural components of models: (1) the reaction kinetics of decomposition and uptake and (2) the functions relating fluxes to soil moisture. We found that the observed interactive patterns were best simulated by a model using Michaelis–Menten decomposition kinetics combined with diffusion of dissolved carbon (C) and enzymes. In contrast, conventional empirical functions that scale decomposition rates directly were unable to properly simulate the main observed interactions. Our best model was able to explain 87% of the variation in the data. Model simulations revealed a central role of Michaelis– Menten kinetics as a driver of temperature sensitivity variations as well as a decoupling of decomposition and respiration C fluxes in the short and mid-term, with general sensitivities to temperature and moisture being more pronounced for respiration. Sensitivity to different model parameters was highest for those affecting diffusion limitations, followed by activation energies, the Michaelis–Menten constant, and carbon use efficiency. Testing against independent data strongly validated the model (R2 D 0:99) and highlighted the importance of initial soil C pool conditions. Our results demonstrate the importance of model structure and the central role of diffusion and reaction kinetics for simulating and understanding complex dynamics in soil C.
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    Proglacial streams and their chronology in the glacier forefields of the Himalayas 

    Tombrink, Gerrit
    E&G Quaternary Science Journal 2018; 67(1) p.33-36
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    Does graded substitution of soy protein concentrate by an insect meal respond on growth and N-utilization in Nile tilapia (Oreochromis niloticus)? 

    Dietz, C.; Liebert, F.
    Aquaculture Reports 2018; 12 p.43-48
    Besides fishmeal, soybean protein is the most common protein source in aquafeed. However, the sustainability of soybean production is criticized. Due to the rapid development of aquaculture, the increasing demand for high value feed proteins has initiated research into alternative and more sustainable proteins for aquafeeds. In order to evaluate one promising alternative protein source, a growth study (56 days) was conducted with juvenile Nile tilapia (Oreochromis niloticus, 35 g on average) with a partial substitution of soybean protein by a partly defatted insect meal from black soldier fly larvae (Hermetia illucens). Growth performance, feed utilization and dietary protein quality parameters were evaluated based on analysed body protein deposition. A control feed (8% fish meal, 37% soy protein concentrate (SPC)) and three iso-nitrogenous and iso-energetic experimental feeds with 25, 50 or 100% replacement of SPC by partly defatted Hermetia meal (HM) were formulated. All feeds supplied essential amino acids as recommended for Nile tilapia. Growth response and protein utilization were examined in a semi-closed in-door water recirculation system. A comparative slaughter technique was applied to generate N deposition data for protein quality evaluation based on the standardized net protein utilization (NPUstd) according to the “Goettingen approach”. All feeds were very well accepted. Replacement of SPC by HM up to 50% improved feed protein quality and result in similar specific growth rate and feed conversion ratio, respectively. However, a higher inclusion rate of HM tended to impair growth, but not the observed protein quality. In conclusion, the replacement of SPC by partly defatted HM up to a level of 50% had no negative effect on growth performance and improved the dietary protein quality of tilapia feeds under study. Insect protein from Hermetia illucens could be a promising option to make aquafeed formulation more flexible and sustainable.
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