RoofKIT - Circular Construction and Solar Energy Use in Practice at the Solar Decathlon Europe 21/22

he contribution of the RoofKIT team to the SDE 21/22 competition is the extension for an existing café in Wuppertal, Germany, to create new functions and living space for the building with simultaneous energetic upgrading. The energy concept targets all renewable resources available on and in the building for energy supply: mainly solar energy which is used via PVT collectors, as well as waste heat from ventilation and grey water which is recovered for pre-heating. As part of the competition, a demonstration unit will be built representing a small cut-out of the extension. An integral building and energy concept combines physical properties of the building with adapted building services technologies to achieve maximum indoor comfort – particularly considering possible overheating of the lightweight construction during summer – and minimum CO2 emissions. The latter extends to the whole lifecycle of the building unit and one of the major goals of the project is to realize an almost completely mono-fraction and circular building construction as a contribution to the urban mining concept

Progress of the ECHo SDR Readout Hardware for Multiplexed MMCs

The electron capture in $^{163}$Holmium (ECHo) experiment seeks to achieve sub-eV sensitivity of the electron neutrino mass through calorimetric decay spectroscopy of $^{163}$Ho in large arrays of cryogenic magnetic microcalorimeters (MMCs). Microwave SQUID multiplexing serves to efficiently increase the number of readout channels, thus calorimeters per array and ultimately per cryostat. A corresponding frequency multiplexing room temperature software-defined radio (SDR) system is in development to enable the readout of this increased number of MMCs per cable. The SDR consists of a custom FPGA platform that provides signal generation and analysis capabilities, as well as tailored signal conversion and analog conditioning front end electronics that enable the room-temperature-to-cryogenic interface. Ultimately, the system will read out 400 multiplexer channels with double pixel detectors through a bandwidth of 4 GHz (IEEE C band). As high-resolution data converters are limited in sample rate, the C-band is split into five sub-bands using a two-stage mixing method. In this contribution, a prototype of the heterodyne RF design is presented. It comprises one of the five 800 MHz sub-bands for a target frequency range between 4 and 8 GHz. Furthermore, the second version of the A/D converter stage is presented, capable of generating and digitizing up to five complex basebands using 1 GSs$^{-1}$ converters, the reference clocks and a flux-ramp signal. We will show first results of their single and combined characterization in the lab. The current state of the prototype hardware enables preliminary measurements, only limited in bandwidth and with slightly higher noise. Potential improvements could be derived and will be implemented in the full bandwidth, 5-sub-band RF PCB design

New players in the interaction between beetle polygalacturonases and plant polygalacturonase-inhibiting proteins: Insights from proteomics and gene expression analyses

Plants possess various defense strategies to counter attacks from microorganisms or herbivores. For example, plants reduce the cell-wall-macerating activity of pathogen- or insect-derived polygalacturonases (PGs) by expressing PG-inhibiting proteins (PGIPs). PGs and PGIPs belong to multi-gene families believed to have been shaped by an evolutionary arms race. The mustard leaf beetle Phaedon cochleariae expresses both active PGs and catalytically inactive PG pseudoenzymes. Previous studies demonstrated that (i) PGIPs target beetle PGs and (ii) the role of PG pseudoenzymes remains elusive, despite having been linked to the pectin degradation pathway. For further insight into the interaction between plant PGIPs and beetle PG family members, we combined affinity purification with proteomics and gene expression analyses, and identified novel inhibitors of beetle PGs from Chinese cabbage (Brassica rapa ssp. pekinensis). A beetle PG pseudoenzyme was not targeted by PGIPs, but instead interacted with PGIP-like proteins. Phylogenetic analysis revealed that PGIP-like proteins clustered apart from “classical” PGIPs but together with proteins, which have been involved in developmental processes. Our results indicate that PGIP-like proteins represent not only interesting novel PG inhibitor candidates in addition to “classical” PGIPs, but also fascinating new players in the arms race between herbivorous beetles and plant defenses

Determination of the charge carrier compensation mechanism in Te-doped GaAs by scanning tunneling microscopy.

We identified the charge carrier compensation mechanism in Te-doped GaAs with atomically resolved scanning tunneling microscopy. Three types of defects were found: tellurium donors (Te-As), Ga vacancies (V-Ga), and Ga vacancy-donor complexes (V-Ga-Te-As). We show quantitatively that the compensation in Te-doped bulk GaAs is exclusively caused by vacancy-donor complexes in contrast to Si-doped GaAs. This is explained with the Fermi-level effect as the universal mechanism leading to Ga vacancy formation in n-doped GaAs, and a Coulomb interaction leading to the formation of the complexes. The quantification of the carrier compensation yields a -3e charge state of V-Ga in bulk GaAs. (C) 2003 American Institute of Physics

Current in open quantum systems

We show that a dissipative current component is present in the dynamics generated by a Liouville-master equation, in addition to the usual component associated with Hamiltonian evolution. The dissipative component originates from coarse graining in time, implicit in a master equation, and needs to be included to preserve current continuity. We derive an explicit expression for the dissipative current in the context of the Markov approximation. Finally, we illustrate our approach with a simple numerical example, in which a quantum particle is coupled to a harmonic phonon bath and dissipation is described by the Pauli master equation.Comment: To appear in Phys. Rev. Let

Magnons in real materials from density-functional theory

We present an implementation of the adiabatic spin-wave dynamics of Niu and Kleinman. This technique allows to decouple the spin and charge excitations of a many-electron system using a generalization of the adiabatic approximation. The only input for the spin-wave equations of motion are the energies and Berry curvatures of many-electron states describing frozen spin spirals. The latter are computed using a newly developed technique based on constrained density-functional theory, within the local spin density approximation and the pseudo-potential plane-wave method. Calculations for iron show an excellent agreement with experiments.Comment: 1 LaTeX file and 1 postscript figur

Oxytocin improves synchronisation in leader-follower interaction

The neuropeptide oxytocin has been shown to affect social interaction. Meanwhile, the underlying mechanism remains highly debated. Using an interpersonal finger-tapping paradigm, we investigated whether oxytocin affects the ability to synchronise with and adapt to the behaviour of others. Dyads received either oxytocin or a non-active placebo, intranasally. We show that in conditions where one dyad-member was tapping to another unresponsive dyad-member – i.e. one was following another who was leading/self-pacing – dyads given oxytocin were more synchronised than dyads given placebo. However, there was no effect when following a regular metronome or when both tappers were mutually adapting to each other. Furthermore, relative to their self-paced tapping partners, oxytocin followers were less variable than placebo followers. Our data suggests that oxytocin improves synchronisation to an unresponsive partner’s behaviour through a reduction in tapping-variability. Hence, oxytocin may facilitate social interaction by enhancing sensorimotor predictions supporting interpersonal synchronisation. The study thus provides novel perspectives on how neurobiological processes relate to socio-psychological behaviour and contributes to the growing evidence that synchronisation and prediction are central to social cognition

Slowing down light in a qubit metamaterial

The rapid progress in quantum information processing leads to a rising demand for devices to control the propagation of electromagnetic wave pulses and to ultimately realize universal and efficient quantum memory. While in recent years, significant progress has been made to realize slow light and quantum memories with atoms at optical frequencies, superconducting circuits in the microwave domain still lack such devices. Here, we demonstrate slowing down electromagnetic waves in a superconducting metamaterial composed of eight qubits coupled to a common waveguide, forming a waveguide quantum electrodynamics system. We analyze two complementary approaches, one relying on dressed states of the Autler–Townes splitting and the other based on a tailored dispersion profile using the qubits tunability. Our time-resolved experiments show reduced group velocities of down to a factor of about 1500 smaller than in vacuum. Depending on the method used, the speed of light can be controlled with an additional microwave tone or an effective qubit detuning. Our findings demonstrate high flexibility of superconducting circuits to realize custom band structures and open the door to microwave dispersion engineering in the quantum regime

Hijacking the mustard-oil bomb: How a glucosinolate-sequestering flea beetle copes with plant myrosinases

Myrosinase enzymes play a key role in the chemical defense of plants of the order Brassicales. Upon herbivory, myrosinases hydrolyze the β-S-linked glucose moiety of glucosinolates, the characteristic secondary metabolites of brassicaceous plants, which leads to the formation of different toxic hydrolysis products. The specialist flea beetle, Phyllotreta armoraciae, is capable of accumulating high levels of glucosinolates in the body and can thus at least partially avoid plant myrosinase activity. In feeding experiments with the myrosinase-deficient Arabidopsis thaliana tgg1 × tgg2 (tgg) mutant and the corresponding Arabidopsis Col-0 wild type, we investigated the influence of plant myrosinase activity on the metabolic fate of ingested glucosinolates in adult P. armoraciae beetles. Arabidopsis myrosinases hydrolyzed a fraction of ingested glucosinolates and thereby reduced the glucosinolate sequestration rate by up to 50% in adult beetles. These results show that P. armoraciae cannot fully prevent glucosinolate hydrolysis; however, the exposure of adult beetles to glucosinolate hydrolysis products had no impact on the beetle’s energy budget under our experimental conditions. To understand how P. armoraciae can partially prevent glucosinolate hydrolysis, we analyzed the short-term fate of ingested glucosinolates and found them to be rapidly absorbed from the gut. In addition, we determined the fate of ingested Arabidopsis myrosinase enzymes in P. armoraciae. Although we detected Arabidopsis myrosinase protein in the feces, we found only traces of myrosinase activity, suggesting that P. armoraciae can inactivate plant myrosinases in the gut. Based on our findings, we propose that the ability to tolerate plant myrosinase activity and a fast glucosinolate uptake mechanism represent key adaptations of P. armoraciae to their brassicaceous host plants