Of dups and dinos : evolution at the K/Pg boundary

Fifteen years into sequencing entire plant genomes, more than 30 paleopolyploidy events could be mapped on the tree of flowering plants (and many more when also transcriptome data sets are considered). While some genome duplications are very old and have occurred early in the evolution of dicots and monocots, or even before, others are more recent and seem to have occurred independently in many different plant lineages. Strikingly, a majority of these duplications date somewhere between 55 and 75 million years ago (mya), and thus likely correlate with the K/Pg boundary. If true, this would suggest that plants that had their genome duplicated at that time, had an increased chance to survive the most recent mass extinction event, at 66 mya, which wiped out a majority of plant and animal life, including all non-avian dinosaurs. Here, we review several processes, both neutral and adaptive, that might explain the establishment of polyploid plants, following the K/Pg mass extinction

Winding Reinforced UHPC Sandwich Structures for Lightweight Jackets for Offshore Megastructures

The paper presents a new type of cross-section for truss elements in an offshore construction's sub structure framework. By combining modern materials, such as ultra-high performance concrete (UHPC) and carbon fibre reinforced polymers in a hollow section, significant weight savings compared to conventional steel structures can be achieved. An extensive experimental programme has been carried out in order to describe the construction's load-bearing behaviour. The article presents an overview of the development process of the design, the methodological implementation of the experimental investigations and the results

Stress prevention in adolescence: evaluation of a multimodal training approach

Subject and aims: This paper reports on the development and evaluation of a stress prevention program for adolescents of grades 8 and 9. The program is based on the problem-solving approach and was developed on the basis of several evaluation studies. It consists of eight weekly training sessions with durations of 90 min each and is accompanied by an e-learning platform. Evaluation studies: The first section of the paper reports on a preceding demand analysis and the initial development and evaluation of the stress prevention program. The second section summarizes the results of providing an additional e-learning platform. Eight online-lessons were designed in correspondence to the training sessions of the face-to-face intervention. The last section of the paper focuses on the results of an evaluation of an optimized training version including the successful elements of the face-to-face and the e-learning platform. Results and conclusion: The results of the final evaluation study showed clear knowledge and self-efficacy improvement and reduction of stress symptoms. Moreover, the training led to positive assessments by most adolescents. Possible actions in contributing to an increase of the training effects beyond those already apparent in the current evaluation studies are additionally discussed

Camelina sativa: a promising oilseed for producing biofuels on marginal lands: Field production and characterization of a low-pectin seed mutant

Camelina sativa L. Crantz (large-seeded false flax) (Camelina) is a promising oilseed crop for production of edible oil, seed meal for animal feed rations, and/or biodiesel feedstock. Because Camelina does not require prime agricultural land, it does not compete with food crops, and requires limited irrigation and nitrogen inputs.In 2015 a five-year field trial of eight named varieties at UNR’s Valley Road facility was completed, with harvested plants evaluated for total dry biomass, seed production, and oil content of cleaned seeds. Columbia, Cheyenne, Calera, and Blaine Creek were ranked as the top four varieties based on performance stability in high seed yield and calculated oil yield. The yields of this study fall within the ranges reported in both irrigated and rainfed locations of the western United States. Improving Camelina for cultivation in Nevada includes developing and identifying mutants with desirable phenotypes (e.g., higher oil content per seed, reduced glucosinolates, reduced seed coat mucilage, triacylglycerol desaturation, and shattering of seed pods). More than 4,700 chemically mutagenized (e.g., EMS, ethyl methane sulfonate) M2 C. sativa lines were generated and have been screened for phenotypes of interest, i.e., oil content as a % of dry weight (DW), reduced glucosinolates, and seed coat mucilage defects. Mucilage is a polysaccharide gum composed of rhamnogalacturonan I (RGI), which can interfere with oil extraction. EMS lines with absent or reduced seed coat mucilage were assayed via a high-throughput colorimetric screen using Ruthenium Red staining. To date 250 M3 mutant lines were screened and four promising lines with reduced mucilage were verified for stability and penetrance in the M4 and M5 generations. The overall rate of mucilage defects in this population is approximately 0.05%. Agronomic data was collected comparing the most promising line, Cs98, with Wild type cv. ‘Celine’ and their F1 cross, Cross 17.1. Cs98 stocks demonstrated their viability through a successful 2016 field trial. A quantitative spectrophotometric mucilage assay validated the seed coat mucilage content compared to wild type “Celine.” Mucilage-defect mutant line Cs98 had smaller seeds and less SCM than WT. Oil derived from Cs98 showed significantly higher macromineral levels (K, Ca, Mg, and P) than WT oil. Transesterification of oil into FAMEs reduced macro mineral content by one-to-two orders of magnitude for both WT and Cs98 FAMEs. Cs98 oil showed significantly lower viscosity at 40 °C than WT oil, perhaps due to lower pectin content. A colorimetric assay of the water washes of the two oils showed that Cs98 had only 57.1% of the mucilage and pectic substances compared to WT. Ongoing research includes characterization of the RGI structure and composition in C. sativa Cs98 mucilage defect lines. Characterization includes backcrossing promising lines to clarify genetic background, and mapping the location of the genetic lesions causing the mucilage defects

Developmental motifs reveal complex structure in cell lineages

Many natural and technological systems are complex, with organisational structures that exhibit characteristic patterns, but defy concise description. One effective approach to analysing such systems is in terms of repeated topological motifs. Here, we extend the motif concept to characterise the dynamic behaviour of complex systems by introducing developmental motifs, which capture patterns of system growth. As a proof of concept, we use developmental motifs to analyse the developmental cell lineage of the nematode Caenorhabditis elegans, revealing a new perspective on its complex structure. We use a family of computational models to explore how biases arising from the dynamics of the developmental gene network, as well as spatial and temporal constraints acting on development, contribute to this complex organisation

UHPC SANDWICH STRUCTURES WITH COMPOSITE COATING UNDER COMPRESSIVE LOAD

Ultra-high-performance concrete (UHPC) sandwich structures with composite coating serve as multipurpose load-bearing elements. The UHPC’s extraordinary compressive strength is used in a multi-material construction element, while issues regarding the concrete’s brittle failure behaviour are properly addressed. A hollow section concrete core is covered by two steel tubes. The outer steel tube is wrapped in a composite material. By this design, UHPC is used in a material- and shape-optimised way with a low dead weight ratio[1] concerning the load-bearing capacity and stability[2]. The cross-section’s hollow shape optimises the construction’s buckling stability while saving self-weight. The composite coating on the column’s outside functions both as a layer increasing the construction’s durability and as a structural component increasing the the maximum and the residual load capacity. Investigations on the construction’s structural behaviour were performed

What are the microscopic events of colloidal membrane fouling?

Due to the complex interplay between surface adsorption and hydrodynamic interactions, representative microscopic mechanisms of colloidal membrane fouling are still not well understood. Numerical simulations overcome experimental limitations such as the temporal and spatial resolution of microscopic events during colloidal membrane fouling: they help to gain deeper insight into fouling processes. This study uses coupled computational fluid dynamics - discrete element methods (CFD-DEM) simulations to examine mechanisms of colloidal fouling in a microfluidic architecture mimicking a porous microfiltration membrane. We pay special attention to how particles can overcome energy barriers leading to adsorption and desorption with each other and with the external and internal membrane surface. Interparticle interaction leads to a transition from the secondary to the primary minimum of the DLVO potential. Adsorbed particles can show re-entrainment or they can glide downstream. Since particles mainly re-suspend as clusters, the inner pore geometry significantly affects the fouling behavior. The findings allow a basic understanding of microscopic fouling events during colloidal filtration. The methodology enables future systematic studies on the interplay of hydrodynamic conditions and surface energy contributions represented by potentials for soft and patchy colloids

Following a Global Script?

Since the end of the Cold War, international organizations and states have developed programs to promote (good) governance at the country level. Regional organizations have gained an important role in governance transfer because they constitute an intermediary level of agency between the nation-state and global institutions. This paper maps the governance transfer of nine regional organizations in the Americas, Asia, Africa, and the Middle East. We analyze the objectives, approaches, and instruments used to promote the creation and transformation of governance institutions in target countries. This comparison shows that similar standards and instruments have been adopted throughout the areas of study, in line with the notion of a global governance script. At the same time, we find important differences with regard to when and how the regional organizations prescribe and promote “good” governance institutions at the national level. Research on diffusion and comparative regionalism is ill- equipped to account for this double finding of increasing similarities and persisting differences. The paper calls for a more agency-centered approach that conceptualizes governance transfer as an institutional choice by states. We identify factors that elicit states’ demand for governance transfer, on the one hand, and that shape its institutional design, on the other.Seit Ende des Kalten Krieges haben Internationale Organisationen und Staaten Programme entwickelt, um „Gutes Regieren“ in Mitgliedstaaten und Drittländern zu fördern. Regionalorganisationen sind als Vermittler zwischen nationalen und globalen Institutionen wichtig für solche Governance-Transfers. Dieses Papier erfasst den Governance-Transfer von neun Regionalorganisationen in den Amerikas, Afrika, Asien und im Nahen Osten. Dabei analysieren wir die Ziele, Ansätze und Instrumente für die Schaffung oder Veränderung von Institutionen in Zielländern. Dieser Vergleich zeigt Ähnlichkeiten bei Standards und Instrumenten, was auf die Ausbreitung eines „globalen Skripts“ für Governance hindeutet. Allerdings unterscheiden sich Organisationen auch darin, wie und wann sie bestimmte Governance-Institutionen in Mitgliedstaaten vorschreiben und fördern. Die Diffusions- und Vergleichende Regionalismusforschung ist auf einen solchen Doppelbefund schlecht vorbereitet. Unser Papier schlägt einen stärker auf Akteure fokussierten Ansatz vor, der Governance-Transfer als Konsequenz staatlicher Entscheidungen ansieht. Wir identifizieren Faktoren, die einerseits die Nachfrage nach solchen Prozessen und andererseits ihre institutionelle Ausgestaltung beeinflussen