Auswirkungen der Fit-for-55-Instrumente auf die Preise in der Luftfahrt

Die Europäische Union strebt mit den Maßnahmen des Fit-for-55-Pakets eine Verringerung der CO2-Emissionen bis 2030 um 55 % an, verglichen mit dem Stand von 1990. Diese Reduktion soll durch verschiedene Maßnahmen erreicht werden, die auch die kommerzielle Luftfahrt betreffen. Dies sind unter anderem eine Verschärfung des Emissionshandels, bei der insbesondere die frei zugeteilten Zertifikate zügig abgebaut werden sollen, eine verpflichtende Beimischungsquote für nachhaltige Flugtreibstoffe an europäischen Flughäfen sowie eine europaweite Mindesthöhe für Steuern auf Treibstoffe. Dadurch verteuern sich die Flüge in verschiedenen Gebieten unterschiedlich

A new model for root growth in soil with macropores

Abstract: Background and aimsThe use of standard dynamic root architecture models to simulate root growth in soil containing macropores failed to reproduce experimentally observed root growth patterns. We thus developed a new, more mechanistic model approach for the simulation of root growth in structured soil. Methods: In our alternative modelling approach, we distinguish between, firstly, the driving force for root growth, which is determined by the orientation of the previous root segment and the influence of gravitropism and, secondly, soil mechanical resistance to root growth. The latter is expressed by its inverse, soil mechanical conductance, and treated similarly to hydraulic conductivity in Darcy’s law. At the presence of macropores, soil mechanical conductance is anisotropic, which leads to a difference between the direction of the driving force and the direction of the root tip movement. Results: The model was tested using data from the literature, at pot scale, at macropore scale, and in a series of simulations where sensitivity to gravity and macropore orientation was evaluated. Conclusions: Qualitative and quantitative comparisons between simulated and experimentally observed root systems showed good agreement, suggesting that the drawn analogy between soil water flow and root growth is a useful one

Preisinduzierte Nachfrageveränderungen durch Fit-for-55-Instrumente in der Luftfahrt

Das Fit-for-55-Maßnahmenpaket der EU bezweckt eine Reduktion der CO2-Emissionen um 55 % bis 2030, gemessen an den Emissionen von 1990. Für die Luftfahrt sind und werden verschiedene Instrumente wirksam, die neben einer Änderung der Treibstoffe auch Steuern und Gebühren enthalten. Je nach Überwälzung der so entstandenen Zusatzkosten von Fluggesellschaften auf die Passagiere, ist auch mit einer Änderung der Ticketpreise für Luftverkehrspassagiere zu rechnen, was sich auf die Höhe und Verteilung der Nachfrage auswirken kann

Multicellularity and the Need for Communication—A Systematic Overview on (Algal) Plasmodesmata and Other Types of Symplasmic Cell Connections

In the evolution of eukaryotes, the transition from unicellular to simple multicellular organisms has happened multiple times. For the development of complex multicellularity, characterized by sophisticated body plans and division of labor between specialized cells, symplasmic intercellular communication is supposed to be indispensable. We review the diversity of symplasmic connectivity among the eukaryotes and distinguish between distinct types of non-plasmodesmatal connections, plasmodesmata-like structures, and ‘canonical’ plasmodesmata on the basis of developmental, structural, and functional criteria. Focusing on the occurrence of plasmodesmata (-like) structures in extant taxa of fungi, brown algae (Phaeophyceae), green algae (Chlorophyta), and streptophyte algae, we present a detailed critical update on the available literature which is adapted to the present classification of these taxa and may serve as a tool for future work. From the data, we conclude that, actually, development of complex multicellularity correlates with symplasmic connectivity in many algal taxa, but there might be alternative routes. Furthermore, we deduce a four-step process towards the evolution of canonical plasmodesmata and demonstrate similarity of plasmodesmata in streptophyte algae and land plants with respect to the occurrence of an ER component. Finally, we discuss the urgent need for functional investigations and molecular work on cell connections in algal organisms

Design and implementation of a GIS based bicycle routing system for the worl wide web (www

Routing systems for motorized vehicles in the internet are well known and widely used. But until recently, there had been no possibility to completely design and individually plan a tourist bicycle tour. This paper describes the conceptual design and implementation of such a bicycle routing system which has been operational since July 2001. Design and implementation of the routing system was done by the Research Center for Geoinformatics and Remote Sensing (FZG) at the University of Vechta in coorporation with the organization ‘Verbund Oldenburger Münsterland e.V.’. To achieve the desired goals, a server/client architecture was used which was based on commercial GIS, database system, and internet components. It is planned that in the near future the bicycle routing system ‘Fahrradies ’ will be extended with the data of neighboring tourist regions as well as with new functions. It will also prove necessary to adapt the system to the new developments of the underlying GIS software and emerging internet standards. Other options include the possibility to integrate the routing system with online navigation and positioning data in the field using wireless communication technology. 1. BICYCLE TOURIST REGION ‘OLDENBURGER MÜNSTERLAND’ The internet has become a very important medium for communication and provides several ways of using maps and geographic data. Today, maps and data created with Geographi

Developmental Plasticity of the Amphibious Liverwort Riccia fluitans

The colonization of land by ancestors of embryophyte plants was one of the most significant evolutionary events in the history of life on earth. The lack of a buffering aquatic environment necessitated adaptations for coping with novel abiotic challenges, particularly high light intensities and desiccation as well as the formation of novel anchoring structures. Bryophytes mark the transition from freshwater to terrestrial habitats and form adaptive features such as rhizoids for soil contact and water uptake, devices for gas exchange along with protective and repellent surface layers. The amphibious liverwort Riccia fluitans can grow as a land form (LF) or water form (WF) and was employed to analyze these critical traits in two different habitats. A combination of light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies was conducted to characterize and compare WF and LF morphologies. A complete phenotypic adaptation of a WF plant to a terrestrial habitat is accomplished within 15 days after the transition. Stable transgenic R. fluitans lines expressing GFP-TUBULIN and mCherry proteins were generated to study cell division and differentiation processes and revealed a higher cell division activity in enlarged meristematic regions at LF apical notches. Morphological studies demonstrated that the R. fluitans WF initiates air pore formation. However, these pores are arrested at an early four cell stage and do not develop further into open pores that could mediate gas exchange. Similarly, also arrested rhizoid initial cells are formed in the WF, which exhibit a distinctive morphology compared to other ventral epidermal cells. Furthermore, we detected that the LF thallus has a reduced surface permeability compared to the WF, likely mediated by formation of thicker LF cell walls and a distinct cuticle compared to the WF. Our R. fluitans developmental plasticity studies can serve as a basis to further investigate in a single genotype the molecular mechanisms of adaptations essential for plants during the conquest of land

Reversible Calcium-Regulated Stopcocks in Legume Sieve Tubes

Sieve tubes of legumes (Fabaceae) contain characteristic P-protein crystalloids with controversial function. We studied their behavior by conventional light, electron, and confocal laser scanning microscopy. In situ, crystalloids are able to undergo rapid (<1 sec) and reversible conversions from the condensed resting state into a dispersed state, in which they occlude the sieve tubes. Crystalloid dispersal is triggered by plasma membrane leakage induced by mechanical injury or permeabilizing substances. Similarly, abrupt turgor changes imposed by osmotic shock cause crystalloid dispersal. Because chelators generally prevent the response, divalent cations appear to be the decisive factor in crystalloid expansion. Cycling between dispersal and condensation can be induced in opened cells by repetitive exchange of bathing media containing either Ca(2+) or chelators. Sr(2+) and Ba(2+), but not Mg(2+), are equally active. In conclusion, the fabacean P-protein crystalloids represent a novel class of mechanically active proteinaceous structures, which provide an efficient mechanism with which to control sieve tube conductivity