EC Visa Facilitation and Readmission Agreements: Implementing a New EU Security Approach in the Neighbourhood

With the Eastern Enlargement successfully completed, the EU is searching for a proper balance between internal security and external stabilisation that is acceptable to all sides. This paper focuses on an EU foreign policy instrument that is a case in point for this struggle: EC visa facilitation and readmission agreements. By looking at the EU's strategy on visa facilitation and readmission, this paper aims to offer a first systematic analysis of the objectives, substance and political implications of these agreements as a means to implement a new EU security approach in the neighbourhood. In offering more relaxed travel conditions in exchange for the signing of an EC readmission agreement and reforming domestic justice and home affairs, the EU has found a new way to press for reforms in neighbouring countries while addressing a major source of discontent in these countries. The analysis concludes with the broader implications of these agreements and argues that even if the facilitated travel opportunities are beneficial for the citizens of the target countries, the positive achievements are undermined by the Schengen enlargement, which makes the new member states tie up their borders to those of their neighbours.EU, EC visa facilitation, readmission agreements, European Neighbourhood Policy, Stabilisation and Association Process, Justice and Home Affairs

Total variation regularization of multi-material topology optimization

This work is concerned with the determination of the diffusion coefficient from distributed data of the state. This problem is related to homogenization theory on the one hand and to regularization theory on the other hand. An approach is proposed which involves total variation regularization combined with a suitably chosen cost functional that promotes the diffusion coefficient assuming prespecified values at each point of the domain. The main difficulty lies in the delicate functional-analytic structure of the resulting nondifferentiable optimization problem with pointwise constraints for functions of bounded variation, which makes the derivation of useful pointwise optimality conditions challenging. To cope with this difficulty, a novel reparametrization technique is introduced. Numerical examples using a regularized semismooth Newton method illustrate the structure of the obtained diffusion coefficient.

Optimal control of semilinear parabolic equations by BV-functions

Optimal control problems for semilinear parabolic equations with control costs involving the total bounded variation seminorm are analyzed. This choice of control cost favors optimal controls which are piecewise constant and it penalizes the number of jumps. It is an appropriate choice if a simple structure of the optimal controls is desired, which, however, is still sufficiently flexible so that good tracking properties can be maintained. Existence of optimal controls, necessary and sufficient optimality conditions, and sparsity properties of the derivatives are obtained. Convergence of a finite element approximation is analyzed and numerical examples illustrating structural properties of the optimal controls are provided.The work of the first author was supported by Spanish Ministerio de Economía y Competitividad under project MTM2014-57531-P. The work of the third author was supported by the Austrian Science Fund (FWF) under grant SFB F32 (SFB “Mathematical Optimization and Applications in Biomedical Sciences”)

“Digital In, Digital Out?“ – Evidence for a Curvilinear Relationship Between IT Experience in Top Management Teams and Firms’ Digital Orientation

To drive digital transformation, firms are increasingly adding IT-experienced executives to their top management team (TMT). Yet, whether IT-experienced executives can aid firms to achieve digital transformation remains unresolved theoretically and empirically. Drawing on human capital and group literature, we propose that there are limits to the benefits received from adding IT-experienced executives to a TMT, resulting in a curvilinear relationship between the share of IT-experienced executives in the TMT and a firm’s digital orientation. We also propose that this relationship is moderated by CEO entrepreneurial orientation and power concentration in the TMT. We test and find support for most of our hypotheses using a secondary panel data set comprising 1,855 firm-year observations from 256 firms listed in the S&P 500 between 2005 and 2017

Prebiotic Nucleoside Synthesis: The Selectivity of Simplicity

Ever since the discovery of nucleic acids 150 years ago, major achievements have been made in understanding and decrypting the fascinating scientific questions of the genetic code. However, the most fundamental question about the origin and the evolution of the genetic code remains a mystery. How did nature manage to build up such intriguingly complex molecules able to encode structure and function from simple building blocks? What conditions were required? How could the precursors survive the unhostile environment of early Earth? Over the past decades, promising synthetic concepts were proposed providing clarity in the field of prebiotic nucleic acid research. In this Minireview, we show the current status and various approaches to answer these fascinating questions

Molecular support for temporal dynamics of induced anti-herbivory defenses in the brown seaweed Fucus Vesiculosus

Grazing by the isopod Idotea baltica induces chemical defenses in the brown seaweed Fucus vesiculosus. A combination of a 33 day induction experiment, feeding choice assays and functional genomic analyses was used to investigate temporal defense patterns and to correlate changes in palatability to changes in gene expression. Despite permanent grazing, seaweed palatability varied over time. Controls were significantly more consumed than grazed pieces only after 18 and 27 days of grazing. Relative to controls, 562/402 genes were up-/down-regulated in seaweed pieces that were grazed for 18 days, i.e. when defense induction was detected. Reprogramming of the regulative expression orchestra (translation, transcription), up-regulation of genes involved in lipid and carbohydrate metabolism, intracellular trafficking, defense and stress response, as well as downregulation of photosynthesis was found in grazed seaweed. These findings indicate short-term temporal variation in defenses and that modified gene expression patterns arise at the same time when grazed seaweed pieces show reduced palatability. Several genes with putative defensive functions and cellular processes potentially involved in defence, such as reallocation of resources from primary to secondary metabolism, were reveale

A Research Program on Innovations in Prehistory and Antiquity

The authors discuss the simultaneous appearance of technological innovations in three key technologies (metallurgy, wheeled vehicles, weighing systems) in the second half of the 4th millennium. This is done from a source-critical perspective because the innova- tions are discussed with the help of dynamic maps from the Topoi project Digital Atlas of Innovations. Besides indications of diffusion gradients influenced by special research conditions, exceptional waves of innovation can be detected for all three technologies in the discussed period. These waves of innovation cannot, however, be generalized but have to be understood on the basis of the respective technology traditions and lines of devel- opment specific to local areas. Monocentric diffusion theories can be clearly disproven, local technology developments and their converging in certain centrally situated regions have to be assumed instead. Similarly, the transfer of objects and their châine opératoire can only be detected rather infrequently, while the adaptation to local socio-economic and environmental factors can be demonstrated

The wHole Story About Fenestrations in LSEC

The porosity of liver sinusoidal endothelial cells (LSEC) ensures bidirectional passive transport of lipoproteins, drugs and solutes between the liver capillaries and the liver parenchyma. This porosity is realized via fenestrations – transcellular pores with diameters in the range of 50–300 nm – typically grouped together in sieve plates. Aging and several liver disorders severely reduce LSEC porosity, decreasing their filtration properties. Over the years, a variety of drugs, stimulants, and toxins have been investigated in the context of altered diameter or frequency of fenestrations. In fact, any change in the porosity, connected with the change in number and/or size of fenestrations is reflected in the overall liver-vascular system crosstalk. Recently, several commonly used medicines have been proposed to have a beneficial effect on LSEC re-fenestration in aging. These findings may be important for the aging populations of the world. In this review we collate the literature on medicines, recreational drugs, hormones and laboratory tools (including toxins) where the effect LSEC morphology was quantitatively analyzed. Moreover, different experimental models of liver pathology are discussed in the context of fenestrations. The second part of this review covers the cellular mechanisms of action to enable physicians and researchers to predict the effect of newly developed drugs on LSEC porosity. To achieve this, we discuss four existing hypotheses of regulation of fenestrations. Finally, we provide a summary of the cellular mechanisms which are demonstrated to tune the porosity of LSEC

Time-lagged response of siberian treeline forests revealed by individual-based modelling

Global warming allows arctic vegetation, which is mainly limited by temperatures, to move north. A change from tundra to taiga will cause a decrease of albedo which further fuels the warming through positive feedback mechanisms. This raises several questions of which we want to address here: (1) Will trees move northwards and thereby change vast treeless tundra areas to taiga? (2) And if so, how long does this response lags behind the temperature changes? To answer these questions we built an individual-based and spatially-explicit vegetation simulator model for larches in Siberia (LAVESI). We present the parameterization and validation of the model's incorporated processes which describe the full life-cycle of the simulated larch species Larix gmelinii. Furthermore, we share results of the first regional-scale simulations testing the model's performance at the Taymyr Peninsula, Russia, ranging from 64-80° N and 92-120° E. In a second experiment, we tested the influence of up to 6 °C warmer and cooler climates on simulated populations. Our results show that already the recent temperature rise will allow forests to expand farther north by roughly one degree, when no seed limitation hinders populations to migrate. Furthermore, climate warming caused populations to densify but with a time-lag of decades. We conclude that in the near future expanding taiga after its first establishment in the former tundra will rapidly form dense tree stands, thus ultimatively fueling the feedback loop of global warming. We show that simulation results of the newly-build vegetation model were reliable, and hence the model can be used as a tool to improve our knowledge about individual-based processes that are important to understand past and future treeline migration

Simulation assisted process chain design for the manufacturing of bulk hybrid shafts with tailored properties

To manufacture semi-finished hybrid workpieces with tailored properties, a finite element simulation assisted process chain design was investigated. This includes the process steps of cross wedge rolling, hot geometry inspection, induction hardening, and fatigue testing. The process chain allows the utilisation of material combinations such as high-strength steels with low-cost and easy to process steels. Here, plasma transferred arc welding is applied to supply the process chain with hybrid specimen featuring different steel grades. An overview of the numerical approaches to consider the various physical phenomena in each of the process steps is presented. The properties of the component behaviour were investigated via the finite element method (FEM) and theoretical approaches. At first, the manufacturing of a hybrid workpiece featuring a near net shape geometry with improved mechanical properties due to recrystallising the weld was computed, using the example of a cross wedge rolling process. The rolling process was designed by means of FEM to determine suitable process parameters and to reduce experimental testing. An optical multi-scale geometry inspection of the hot workpiece is meant to be carried out after each manufacturing step to detect potential undesired forming or cooling-induced deformations. Due to the heat transfer from the hot component to the ambient medium, an optical measurement is affected by the developing inhomogeneous refractive index field in air. To gain a basic understanding of the refractive index field and induced light deflection effects, computations were conducted using heat transfer and ray tracing simulations. According to the proposed process route, a subsequent local heat treatment of the hybrid component is required to adapt the mechanical properties by a spray cooling assisted induction hardening. The heat treatment step was computed via a 2D FEM calculation. After finishing by machining, the hybrid material shafts are examined in fatigue tests under load conditions. To predict the component’s lifetime under rolling contact fatigue, a damage accumulation model was combined with an FE simulation. The resulting residual stress state after quenching and the geometry after the finishing process were used as input data for the fatigue life calculations