Beyond Bidimensionality: Parameterized Subexponential Algorithms on Directed Graphs

We develop two different methods to achieve subexponential time parameterized algorithms for problems on sparse directed graphs. We exemplify our approaches with two well studied problems. For the first problem, {\sc $k$-Leaf Out-Branching}, which is to find an oriented spanning tree with at least $k$ leaves, we obtain an algorithm solving the problem in time $2^{O(\sqrt{k} \log k)} n+ n^{O(1)}$ on directed graphs whose underlying undirected graph excludes some fixed graph $H$ as a minor. For the special case when the input directed graph is planar, the running time can be improved to $2^{O(\sqrt{k})}n + n^{O(1)}$. The second example is a generalization of the {\sc Directed Hamiltonian Path} problem, namely {\sc $k$-Internal Out-Branching}, which is to find an oriented spanning tree with at least $k$ internal vertices. We obtain an algorithm solving the problem in time $2^{O(\sqrt{k} \log k)} + n^{O(1)}$ on directed graphs whose underlying undirected graph excludes some fixed apex graph $H$ as a minor. Finally, we observe that for any $\epsilon>0$, the {\sc $k$-Directed Path} problem is solvable in time $O((1+\epsilon)^k n^{f(\epsilon)})$, where $f$ is some function of \ve. Our methods are based on non-trivial combinations of obstruction theorems for undirected graphs, kernelization, problem specific combinatorial structures and a layering technique similar to the one employed by Baker to obtain PTAS for planar graphs

Mitochondrial biogenesis and dynamics in the developing and diseased heart

The mitochondrion is a complex organelle that serves essential roles in energy transduction, ATP production, and a myriad of cellular signaling events. A finely tuned regulatory network orchestrates the biogenesis, maintenance, and turnover of mitochondria. The high-capacity mitochondrial system in the heart is regulated in a dynamic way to generate and consume enormous amounts of ATP in order to support the constant pumping function in the context of changing energy demands. This review describes the regulatory circuitry and downstream events involved in mitochondrial biogenesis and its coordination with mitochondrial dynamics in developing and diseased hearts

Biomass Production of the EDEN ISS Space Greenhouse in Antarctica During the 2018 Experiment Phase

The EDEN ISS greenhouse is a space-analog test facility near the German Neumayer III station in Antarctica. The facility is part of the project of the same name and was designed and built starting from March 2015 and eventually deployed in Antarctica in January 2018. The nominal operation of the greenhouse started on February 7th and continued until the 20th of November. The purpose of the facility is to enable multidisciplinary research on topics related to future plant cultivation on human space exploration missions. Research on food quality and safety, plant health monitoring, microbiology, system validation, human factors and horticultural sciences was conducted. Part of the latter is the determination of the biomass production of the different crops. The data on this topic is presented in this paper. During the first season 26 different crops were grown on the 12.5 m2 cultivation area of the greenhouse. A large number of crops were grown continuously throughout the 9 months of operation, but there were also crops that were only grown a few times for test purposes. The focus of this season was on growing lettuce, leafy greens and fresh vegetables. In total more than 268 kg of edible biomass was produced by the EDEN ISS greenhouse facility in 2018. Most of the harvest was cucumbers (67 kg), lettuces (56 kg), leafy greens (49 kg), and tomatoes (50 kg) complemented with smaller amounts of herbs (12 kg), radish (8 kg), and kohlrabi (19 kg). The environmental set points for the crops were 330–600 µmol/(m2∗s) LED light, 21◦C, ∼65% relative humidity, 1000 ppm and the photoperiod was 17 h per day. The overall yearly productivity of the EDEN ISS greenhouse in 2018 was 27.4 kg/m2, which is equal to 0.075 kg/(m2∗d). This paper shows in detail the data on edible and inedible biomass production of each crop grown in the EDEN ISS greenhouse in Antarctica during the 2018 season

Fragmentation of Molecules by Fast Ion Impact

Single ionization of simple molecules, e.g. H2, CO2, by fast charged particle impact has been studied using a reaction microscope. By measuring the momenta of the emitted electron and the recoil ionic fragment in coincidence, channel-selective low-energy electron spectra have been recorded. The experimental cross sections will be presented, compared with the predictions of state-of-the-art CDW-EIS calculations and discussed in terms of molecular effects such as (i) autoionization and predissociation channels, (ii) interference patterns resulting from the two-center geometry of the diatomic molecule, in analogy to Young\u27s double-slit experiment and (iii) dependence of the electron emission on the orientation of the molecular axis

Lithologic Controls on Silicate Weathering Regimes of Temperate Planets

Weathering of silicate rocks at a planetary surface can draw down CO2 from the atmosphere for eventual burial and long-term storage in the planetary interior. This process is thought to provide essential negative feedback to the carbonate-silicate cycle (carbon cycle) to maintain clement climates on Earth and potentially similar temperate exoplanets. We implement thermodynamics to determine weathering rates as a function of surface lithology (rock type). These rates provide upper limits that allow the maximum rate of weathering in regulating climate to be estimated. This modeling shows that the weathering of mineral assemblages in a given rock, rather than individual minerals, is crucial to determine weathering rates at planetary surfaces. By implementing a fluid-transport-controlled approach, we further mimic chemical kinetics and thermodynamics to determine weathering rates for three types of rocks inspired by the lithologies of Earthʼs continental and oceanic crust, and its upper mantle. We find that thermodynamic weathering rates of a continental crust-like lithology are about one to two orders of magnitude lower than those of a lithology characteristic of the oceanic crust. We show that when the CO2 partial pressure decreases or surface temperature increases, thermodynamics rather than kinetics exerts a strong control on weathering. The kinetically and thermodynamically limited regimes of weathering depend on lithology, whereas the supply-limited weathering is independent of lithology. Our results imply that the temperature sensitivity of thermodynamically limited silicate weathering may instigate a positive feedback to the carbon cycle, in which the weathering rate decreases as the surface temperature increases

Hype Cycle Assessment Of Emerging Technologies For Battery Production

The demand for battery-powered electric vehicles is growing rapidly as more and more OEMs are shifting their strategy towards an all-electric vehicle fleet. The lithium-ion battery cell is considered as the core component in terms of performance, range and price of electric vehicles. Since the development of the functional principle of the lithium-ion battery, both the product and the associated production technology have evolved significantly. OEMs, start-ups, equipment suppliers and other players in the automotive industry are investing heavily in research and development of various technologies to improve both the battery as a product and its production. An essential aspect is to enable sustainable battery production. While breakthroughs in battery technology are regularly announced, the actual merits of the technologies and the potential remain uncertain until commercial deployment. The aim of this paper is to systematically identify upcoming breakthroughs and announced innovations to provide an overview of promising battery technologies that companies should focus on to enable the planning of resilient and sustainable production systems. Hence, a hype cycle assessment following Gartner was adopted as the underlying approach to evaluate battery technologies for deployment in electromobility and mass production. First, various technologies, innovations, research activities and announcements in the field of battery technologies were screened, recorded and classified in order to obtain an overview of the current state of developments on both product and production levels. This includes an overview of innovations in battery design and configuration as well as process technologies and production systems. Subsequently, these technologies are evaluated according to predefined evaluation criteria in order to enable a systematic classification of the individual technologies in the hype cycle. The result is a consolidated overview of emerging battery technologies for sustainable battery production and a display for further recommendations for relevant companies and stakeholders

Overcoming the roadblocks to cardiac cell therapy using tissue engineering

Transplantations of various stem cells or their progeny have repeatedly improved cardiac performance in animal models of myocardial injury; however, the benefits observed in clinical trials have been generally less consistent. Some of the recognized challenges are poor engraftment of implanted cells and, in the case of human cardiomyocytes, functional immaturity and lack of electrical integration, leading to limited contribution to the heart’s contractile activity and increased arrhythmogenic risks. Advances in tissue and genetic engineering techniques are expected to improve the survival and integration of transplanted cells, and to support structural, functional, and bioenergetic recovery of the recipient hearts. Specifically, application of a prefabricated cardiac tissue patch to prevent dilation and to improve pumping efficiency of the infarcted heart offers a promising strategy for making stem cell therapy a clinical reality. [Display omitted

Evaluation of Arctic land snow cover characteristics, surface albedo and temperature during the transition seasons from regional climate model simulations and satellite data

This paper evaluates the simulated Arctic land snow cover duration, snow water equivalent, snow cover fraction, surface albedo and land surface temperature in the regional climate model HIRHAM5 during 2008-2010, compared with various satellite and reanalysis data and one further regional climate model (COSMO-CLM). HIRHAM5 shows a general agreement in the spatial patterns and annual course of these variables, although distinct biases for specific regions and months are obvious. The most prominent biases occur for east Siberian deciduous forest albedo, which is overestimated in the simulation for snow covered conditions in spring. This may be caused by the simplified albedo parameterization (e.g. non-consideration of different forest types and neglecting the effect of fallen leaves and branches on snow for deciduous tree forest). The land surface temperature biases mirror the albedo biases in their spatial and temporal structures. The snow cover fraction and albedo biases can explain the simulated land surface temperature bias of ca. -3 °C over the Siberian forest area in spring