@article{194, abstract = {Ants are emerging model systems to study cellular signaling because distinct castes possess different physiologic phenotypes within the same colony. Here we studied the functionality of inotocin signaling, an insect ortholog of mammalian oxytocin (OT), which was recently discovered in ants. In Lasius ants, we determined that specialization within the colony, seasonal factors, and physiologic conditions down-regulated the expression of the OT-like signaling system. Given this natural variation, we interrogated its function using RNAi knockdowns. Next-generation RNA sequencing of OT-like precursor knock-down ants highlighted its role in the regulation of genes involved in metabolism. Knock-down ants exhibited higher walking activity and increased self-grooming in the brood chamber. We propose that OT-like signaling in ants is important for regulating metabolic processes and locomotion.}, author = {Liutkeviciute, Zita and Gil Mansilla, Esther and Eder, Thomas and Casillas Perez, Barbara E and Giulia Di Giglio, Maria and Muratspahić, Edin and Grebien, Florian and Rattei, Thomas and Muttenthaler, Markus and Cremer, Sylvia and Gruber, Christian}, issn = {0892-6638}, journal = {The FASEB Journal}, number = {12}, pages = {6808--6821}, publisher = {FASEB}, title = {{Oxytocin-like signaling in ants influences metabolic gene expression and locomotor activity}}, doi = {10.1096/fj.201800443}, volume = {32}, year = {2018}, } @article{312, abstract = {Motivated by biological questions, we study configurations of equal spheres that neither pack nor cover. Placing their centers on a lattice, we define the soft density of the configuration by penalizing multiple overlaps. Considering the 1-parameter family of diagonally distorted 3-dimensional integer lattices, we show that the soft density is maximized at the FCC lattice.}, author = {Edelsbrunner, Herbert and Iglesias Ham, Mabel}, issn = {0895-4801}, journal = {SIAM J Discrete Math}, number = {1}, pages = {750 -- 782}, publisher = {Society for Industrial and Applied Mathematics }, title = {{On the optimality of the FCC lattice for soft sphere packing}}, doi = {10.1137/16M1097201}, volume = {32}, year = {2018}, } @inproceedings{140, abstract = {Reachability analysis is difficult for hybrid automata with affine differential equations, because the reach set needs to be approximated. Promising abstraction techniques usually employ interval methods or template polyhedra. Interval methods account for dense time and guarantee soundness, and there are interval-based tools that overapproximate affine flowpipes. But interval methods impose bounded and rigid shapes, which make refinement expensive and fixpoint detection difficult. Template polyhedra, on the other hand, can be adapted flexibly and can be unbounded, but sound template refinement for unbounded reachability analysis has been implemented only for systems with piecewise constant dynamics. We capitalize on the advantages of both techniques, combining interval arithmetic and template polyhedra, using the former to abstract time and the latter to abstract space. During a CEGAR loop, whenever a spurious error trajectory is found, we compute additional space constraints and split time intervals, and use these space-time interpolants to eliminate the counterexample. Space-time interpolation offers a lazy, flexible framework for increasing precision while guaranteeing soundness, both for error avoidance and fixpoint detection. To the best of out knowledge, this is the first abstraction refinement scheme for the reachability analysis over unbounded and dense time of affine hybrid systems, which is both sound and automatic. We demonstrate the effectiveness of our algorithm with several benchmark examples, which cannot be handled by other tools.}, author = {Frehse, Goran and Giacobbe, Mirco and Henzinger, Thomas A}, issn = {0302-9743}, location = {Oxford, United Kingdom}, pages = {468 -- 486}, publisher = {Springer}, title = {{Space-time interpolants}}, doi = {10.1007/978-3-319-96145-3_25}, volume = {10981}, year = {2018}, } @inproceedings{5788, abstract = {In two-player games on graphs, the players move a token through a graph to produce an infinite path, which determines the winner or payoff of the game. Such games are central in formal verification since they model the interaction between a non-terminating system and its environment. We study bidding games in which the players bid for the right to move the token. Two bidding rules have been defined. In Richman bidding, in each round, the players simultaneously submit bids, and the higher bidder moves the token and pays the other player. Poorman bidding is similar except that the winner of the bidding pays the “bank” rather than the other player. While poorman reachability games have been studied before, we present, for the first time, results on infinite-duration poorman games. A central quantity in these games is the ratio between the two players’ initial budgets. The questions we study concern a necessary and sufficient ratio with which a player can achieve a goal. For reachability objectives, such threshold ratios are known to exist for both bidding rules. We show that the properties of poorman reachability games extend to complex qualitative objectives such as parity, similarly to the Richman case. Our most interesting results concern quantitative poorman games, namely poorman mean-payoff games, where we construct optimal strategies depending on the initial ratio, by showing a connection with random-turn based games. The connection in itself is interesting, because it does not hold for reachability poorman games. We also solve the complexity problems that arise in poorman bidding games.}, author = {Avni, Guy and Henzinger, Thomas A and Ibsen-Jensen, Rasmus}, isbn = {9783030046118}, issn = {0302-9743}, location = {Oxford, UK}, pages = {21--36}, publisher = {Springer}, title = {{Infinite-duration poorman-bidding games}}, doi = {10.1007/978-3-030-04612-5_2}, volume = {11316}, year = {2018}, } @inproceedings{5679, abstract = {We study the almost-sure termination problem for probabilistic programs. First, we show that supermartingales with lower bounds on conditional absolute difference provide a sound approach for the almost-sure termination problem. Moreover, using this approach we can obtain explicit optimal bounds on tail probabilities of non-termination within a given number of steps. Second, we present a new approach based on Central Limit Theorem for the almost-sure termination problem, and show that this approach can establish almost-sure termination of programs which none of the existing approaches can handle. Finally, we discuss algorithmic approaches for the two above methods that lead to automated analysis techniques for almost-sure termination of probabilistic programs.}, author = {Huang, Mingzhang and Fu, Hongfei and Chatterjee, Krishnendu}, editor = {Ryu, Sukyoung}, isbn = {9783030027674}, issn = {0302-9743}, location = {Wellington, New Zealand}, pages = {181--201}, publisher = {Springer}, title = {{New approaches for almost-sure termination of probabilistic programs}}, doi = {10.1007/978-3-030-02768-1_11}, volume = {11275}, year = {2018}, } @article{5672, abstract = {The release of IgM is the first line of an antibody response and precedes the generation of high affinity IgG in germinal centers. Once secreted by freshly activated plasmablasts, IgM is released into the efferent lymph of reactive lymph nodes as early as 3 d after immunization. As pentameric IgM has an enormous size of 1,000 kD, its diffusibility is low, and one might wonder how it can pass through the densely lymphocyte-packed environment of a lymph node parenchyma in order to reach its exit. In this issue of JEM, Thierry et al. show that, in order to reach the blood stream, IgM molecules take a specific micro-anatomical route via lymph node conduits.}, author = {Reversat, Anne and Sixt, Michael K}, issn = {0022-1007}, journal = {Journal of Experimental Medicine}, number = {12}, pages = {2959--2961}, publisher = {Rockefeller University Press}, title = {{IgM's exit route}}, doi = {10.1084/jem.20181934}, volume = {215}, year = {2018}, } @article{703, abstract = {We consider the NP-hard problem of MAP-inference for undirected discrete graphical models. We propose a polynomial time and practically efficient algorithm for finding a part of its optimal solution. Specifically, our algorithm marks some labels of the considered graphical model either as (i) optimal, meaning that they belong to all optimal solutions of the inference problem; (ii) non-optimal if they provably do not belong to any solution. With access to an exact solver of a linear programming relaxation to the MAP-inference problem, our algorithm marks the maximal possible (in a specified sense) number of labels. We also present a version of the algorithm, which has access to a suboptimal dual solver only and still can ensure the (non-)optimality for the marked labels, although the overall number of the marked labels may decrease. We propose an efficient implementation, which runs in time comparable to a single run of a suboptimal dual solver. Our method is well-scalable and shows state-of-the-art results on computational benchmarks from machine learning and computer vision.}, author = {Shekhovtsov, Alexander and Swoboda, Paul and Savchynskyy, Bogdan}, issn = {0162-8828}, journal = {IEEE Transactions on Pattern Analysis and Machine Intelligence}, number = {7}, pages = {1668--1682}, publisher = {IEEE}, title = {{Maximum persistency via iterative relaxed inference with graphical models}}, doi = {10.1109/TPAMI.2017.2730884}, volume = {40}, year = {2018}, } @inproceedings{6941, abstract = {Bitcoin has become the most successful cryptocurrency ever deployed, and its most distinctive feature is that it is decentralized. Its underlying protocol (Nakamoto consensus) achieves this by using proof of work, which has the drawback that it causes the consumption of vast amounts of energy to maintain the ledger. Moreover, Bitcoin mining dynamics have become less distributed over time. Towards addressing these issues, we propose SpaceMint, a cryptocurrency based on proofs of space instead of proofs of work. Miners in SpaceMint dedicate disk space rather than computation. We argue that SpaceMint’s design solves or alleviates several of Bitcoin’s issues: most notably, its large energy consumption. SpaceMint also rewards smaller miners fairly according to their contribution to the network, thus incentivizing more distributed participation. This paper adapts proof of space to enable its use in cryptocurrency, studies the attacks that can arise against a Bitcoin-like blockchain that uses proof of space, and proposes a new blockchain format and transaction types to address these attacks. Our prototype shows that initializing 1 TB for mining takes about a day (a one-off setup cost), and miners spend on average just a fraction of a second per block mined. Finally, we provide a game-theoretic analysis modeling SpaceMint as an extensive game (the canonical game-theoretic notion for games that take place over time) and show that this stylized game satisfies a strong equilibrium notion, thereby arguing for SpaceMint ’s stability and consensus.}, author = {Park, Sunoo and Kwon, Albert and Fuchsbauer, Georg and Gazi, Peter and Alwen, Joel F and Pietrzak, Krzysztof Z}, booktitle = {22nd International Conference on Financial Cryptography and Data Security}, isbn = {9783662583869}, issn = {1611-3349}, location = {Nieuwpoort, Curacao}, pages = {480--499}, publisher = {Springer Nature}, title = {{SpaceMint: A cryptocurrency based on proofs of space}}, doi = {10.1007/978-3-662-58387-6_26}, volume = {10957}, year = {2018}, } @inbook{6525, abstract = {This chapter finds an agreement of equivariant indices of semi-classical homomorphisms between pairwise mirror branes in the GL2 Higgs moduli space on a Riemann surface. On one side of the agreement, components of the Lagrangian brane of U(1,1) Higgs bundles, whose mirror was proposed by Hitchin to be certain even exterior powers of the hyperholomorphic Dirac bundle on the SL2 Higgs moduli space, are present. The agreement arises from a mysterious functional equation. This gives strong computational evidence for Hitchin’s proposal.}, author = {Hausel, Tamás and Mellit, Anton and Pei, Du}, booktitle = {Geometry and Physics: Volume I}, isbn = {9780198802013}, pages = {189--218}, publisher = {Oxford University Press}, title = {{Mirror symmetry with branes by equivariant verlinde formulas}}, doi = {10.1093/oso/9780198802013.003.0009}, year = {2018}, } @article{438, abstract = {The MazF toxin sequence-specifically cleaves single-stranded RNA upon various stressful conditions, and it is activated as a part of the mazEF toxin–antitoxin module in Escherichia coli. Although autoregulation of mazEF expression through the MazE antitoxin-dependent transcriptional repression has been biochemically characterized, less is known about post-transcriptional autoregulation, as well as how both of these autoregulatory features affect growth of single cells during conditions that promote MazF production. Here, we demonstrate post-transcriptional autoregulation of mazF expression dynamics by MazF cleaving its own transcript. Single-cell analyses of bacterial populations during ectopic MazF production indicated that two-level autoregulation of mazEF expression influences cell-to-cell growth rate heterogeneity. The increase in growth rate heterogeneity is governed by the MazE antitoxin, and tuned by the MazF-dependent mazF mRNA cleavage. Also, both autoregulatory features grant rapid exit from the stress caused by mazF overexpression. Time-lapse microscopy revealed that MazF-mediated cleavage of mazF mRNA leads to increased temporal variability in length of individual cells during ectopic mazF overexpression, as explained by a stochastic model indicating that mazEF mRNA cleavage underlies temporal fluctuations in MazF levels during stress.}, author = {Nikolic, Nela and Bergmiller, Tobias and Vandervelde, Alexandra and Albanese, Tanino and Gelens, Lendert and Moll, Isabella}, journal = {Nucleic Acids Research}, number = {6}, pages = {2918--2931}, publisher = {Oxford University Press}, title = {{Autoregulation of mazEF expression underlies growth heterogeneity in bacterial populations}}, doi = {10.1093/nar/gky079}, volume = {46}, year = {2018}, } @misc{5569, abstract = {Nela Nikolic, Tobias Bergmiller, Alexandra Vandervelde, Tanino G. Albanese, Lendert Gelens, and Isabella Moll (2018) “Autoregulation of mazEF expression underlies growth heterogeneity in bacterial populations” Nucleic Acids Research, doi: 10.15479/AT:ISTA:74; microscopy experiments by Tobias Bergmiller; image and data analysis by Nela Nikolic.}, author = {Bergmiller, Tobias and Nikolic, Nela}, keywords = {microscopy, microfluidics}, publisher = {Institute of Science and Technology Austria}, title = {{Time-lapse microscopy data}}, doi = {10.15479/AT:ISTA:74}, year = {2018}, } @article{6774, abstract = {A central problem of algebraic topology is to understand the homotopy groups 𝜋𝑑(𝑋) of a topological space X. For the computational version of the problem, it is well known that there is no algorithm to decide whether the fundamental group 𝜋1(𝑋) of a given finite simplicial complex X is trivial. On the other hand, there are several algorithms that, given a finite simplicial complex X that is simply connected (i.e., with 𝜋1(𝑋) trivial), compute the higher homotopy group 𝜋𝑑(𝑋) for any given 𝑑≥2 . However, these algorithms come with a caveat: They compute the isomorphism type of 𝜋𝑑(𝑋) , 𝑑≥2 as an abstract finitely generated abelian group given by generators and relations, but they work with very implicit representations of the elements of 𝜋𝑑(𝑋) . Converting elements of this abstract group into explicit geometric maps from the d-dimensional sphere 𝑆𝑑 to X has been one of the main unsolved problems in the emerging field of computational homotopy theory. Here we present an algorithm that, given a simply connected space X, computes 𝜋𝑑(𝑋) and represents its elements as simplicial maps from a suitable triangulation of the d-sphere 𝑆𝑑 to X. For fixed d, the algorithm runs in time exponential in size(𝑋) , the number of simplices of X. Moreover, we prove that this is optimal: For every fixed 𝑑≥2 , we construct a family of simply connected spaces X such that for any simplicial map representing a generator of 𝜋𝑑(𝑋) , the size of the triangulation of 𝑆𝑑 on which the map is defined, is exponential in size(𝑋) .}, author = {Filakovský, Marek and Franek, Peter and Wagner, Uli and Zhechev, Stephan Y}, issn = {2367-1734}, journal = {Journal of Applied and Computational Topology}, number = {3-4}, pages = {177--231}, publisher = {Springer}, title = {{Computing simplicial representatives of homotopy group elements}}, doi = {10.1007/s41468-018-0021-5}, volume = {2}, year = {2018}, } @phdthesis{52, abstract = {In this thesis we will discuss systems of point interacting fermions, their stability and other spectral properties. Whereas for bosons a point interacting system is always unstable this ques- tion is more subtle for a gas of two species of fermions. In particular the answer depends on the mass ratio between these two species. Most of this work will be focused on the N + M model which consists of two species of fermions with N, M particles respectively which interact via point interactions. We will introduce this model using a formal limit and discuss the N + 1 system in more detail. In particular, we will show that for mass ratios above a critical one, which does not depend on the particle number, the N + 1 system is stable. In the context of this model we will prove rigorous versions of Tan relations which relate various quantities of the point-interacting model. By restricting the N + 1 system to a box we define a finite density model with point in- teractions. In the context of this system we will discuss the energy change when introducing a point-interacting impurity into a system of non-interacting fermions. We will see that this change in energy is bounded independently of the particle number and in particular the bound only depends on the density and the scattering length. As another special case of the N + M model we will show stability of the 2 + 2 model for mass ratios in an interval around one. Further we will investigate a different model of point interactions which was discussed before in the literature and which is, contrary to the N + M model, not given by a limiting procedure but is based on a Dirichlet form. We will show that this system behaves trivially in the thermodynamic limit, i.e. the free energy per particle is the same as the one of the non-interacting system.}, author = {Moser, Thomas}, issn = {2663-337X}, pages = {115}, publisher = {Institute of Science and Technology Austria}, title = {{Point interactions in systems of fermions}}, doi = {10.15479/AT:ISTA:th_1043}, year = {2018}, } @article{154, abstract = {We give a lower bound on the ground state energy of a system of two fermions of one species interacting with two fermions of another species via point interactions. We show that there is a critical mass ratio m2 ≈ 0.58 such that the system is stable, i.e., the energy is bounded from below, for m∈[m2,m2−1]. So far it was not known whether this 2 + 2 system exhibits a stable region at all or whether the formation of four-body bound states causes an unbounded spectrum for all mass ratios, similar to the Thomas effect. Our result gives further evidence for the stability of the more general N + M system.}, author = {Moser, Thomas and Seiringer, Robert}, issn = {1572-9656}, journal = {Mathematical Physics Analysis and Geometry}, number = {3}, publisher = {Springer}, title = {{Stability of the 2+2 fermionic system with point interactions}}, doi = {10.1007/s11040-018-9275-3}, volume = {21}, year = {2018}, } @phdthesis{323, abstract = {In the here presented thesis, we explore the role of branched actin networks in cell migration and antigen presentation, the two most relevant processes in dendritic cell biology. Branched actin networks construct lamellipodial protrusions at the leading edge of migrating cells. These are typically seen as adhesive structures, which mediate force transduction to the extracellular matrix that leads to forward locomotion. We ablated Arp2/3 nucleation promoting factor WAVE in DCs and found that the resulting cells lack lamellipodial protrusions. Instead, depending on the maturation state, one or multiple filopodia were formed. By challenging these cells in a variety of migration assays we found that lamellipodial protrusions are dispensable for the locomotion of leukocytes and actually dampen the speed of migration. However, lamellipodia are critically required to negotiate complex environments that DCs experience while they travel to the next draining lymph node. Taken together our results suggest that leukocyte lamellipodia have rather a sensory- than a force transducing function. Furthermore, we show for the first time structure and dynamics of dendritic cell F-actin at the immunological synapse with naïve T cells. Dendritic cell F-actin appears as dynamic foci that are nucleated by the Arp2/3 complex. WAVE ablated dendritic cells show increased membrane tension, leading to an altered ultrastructure of the immunological synapse and severe T cell priming defects. These results point towards a previously unappreciated role of the cellular mechanics of dendritic cells in T cell activation. Additionally, we present a novel cell culture based system for the differentiation of dendritic cells from conditionally immortalized hematopoietic precursors. These precursor cells are genetically tractable via the CRISPR/Cas9 system while they retain their ability to differentiate into highly migratory dendritic cells and other immune cells. This will foster the study of all aspects of dendritic cell biology and beyond. }, author = {Leithner, Alexander F}, issn = {2663-337X}, pages = {99}, publisher = {Institute of Science and Technology Austria}, title = {{Branched actin networks in dendritic cell biology}}, doi = {10.15479/AT:ISTA:th_998}, year = {2018}, } @article{542, abstract = {The t-haplotype, a mouse meiotic driver found on chromosome 17, has been a model for autosomal segregation distortion for close to a century, but several questions remain regarding its biology and evolutionary history. A recently published set of population genomics resources for wild mice includes several individuals heterozygous for the t-haplotype, which we use to characterize this selfish element at the genomic and transcriptomic level. Our results show that large sections of the t-haplotype have been replaced by standard homologous sequences, possibly due to occasional events of recombination, and that this complicates the inference of its history. As expected for a long genomic segment of very low recombination, the t-haplotype carries an excess of fixed nonsynonymous mutations compared to the standard chromosome. This excess is stronger for regions that have not undergone recent recombination, suggesting that occasional gene flow between the t and the standard chromosome may provide a mechanism to regenerate coding sequences that have accumulated deleterious mutations. Finally, we find that t-complex genes with altered expression largely overlap with deleted or amplified regions, and that carrying a t-haplotype alters the testis expression of genes outside of the t-complex, providing new leads into the pathways involved in the biology of this segregation distorter.}, author = {Kelemen, Réka K and Vicoso, Beatriz}, journal = {Genetics}, number = {1}, pages = {365 -- 375}, publisher = {Genetics Society of America}, title = {{Complex history and differentiation patterns of the t-haplotype, a mouse meiotic driver}}, doi = {10.1534/genetics.117.300513}, volume = {208}, year = {2018}, } @article{3, abstract = {SETD5 gene mutations have been identified as a frequent cause of idiopathic intellectual disability. Here we show that Setd5-haploinsufficient mice present developmental defects such as abnormal brain-to-body weight ratios and neural crest defect-associated phenotypes. Furthermore, Setd5-mutant mice show impairments in cognitive tasks, enhanced long-term potentiation, delayed ontogenetic profile of ultrasonic vocalization, and behavioral inflexibility. Behavioral issues are accompanied by abnormal expression of postsynaptic density proteins previously associated with cognition. Our data additionally indicate that Setd5 regulates RNA polymerase II dynamics and gene transcription via its interaction with the Hdac3 and Paf1 complexes, findings potentially explaining the gene expression defects observed in Setd5-haploinsufficient mice. Our results emphasize the decisive role of Setd5 in a biological pathway found to be disrupted in humans with intellectual disability and autism spectrum disorder.}, author = {Deliu, Elena and Arecco, Niccoló and Morandell, Jasmin and Dotter, Christoph and Contreras, Ximena and Girardot, Charles and Käsper, Eva and Kozlova, Alena and Kishi, Kasumi and Chiaradia, Ilaria and Noh, Kyung and Novarino, Gaia}, journal = {Nature Neuroscience}, number = {12}, pages = {1717 -- 1727}, publisher = {Nature Publishing Group}, title = {{Haploinsufficiency of the intellectual disability gene SETD5 disturbs developmental gene expression and cognition}}, doi = {10.1038/s41593-018-0266-2}, volume = {21}, year = {2018}, } @article{15, abstract = {Although much is known about the physiological framework of T cell motility, and numerous rate-limiting molecules have been identified through loss-of-function approaches, an integrated functional concept of T cell motility is lacking. Here, we used in vivo precision morphometry together with analysis of cytoskeletal dynamics in vitro to deconstruct the basic mechanisms of T cell migration within lymphatic organs. We show that the contributions of the integrin LFA-1 and the chemokine receptor CCR7 are complementary rather than positioned in a linear pathway, as they are during leukocyte extravasation from the blood vasculature. Our data demonstrate that CCR7 controls cortical actin flows, whereas integrins mediate substrate friction that is sufficient to drive locomotion in the absence of considerable surface adhesions and plasma membrane flux.}, author = {Hons, Miroslav and Kopf, Aglaja and Hauschild, Robert and Leithner, Alexander F and Gärtner, Florian R and Abe, Jun and Renkawitz, Jörg and Stein, Jens and Sixt, Michael K}, journal = {Nature Immunology}, number = {6}, pages = {606 -- 616}, publisher = {Nature Publishing Group}, title = {{Chemokines and integrins independently tune actin flow and substrate friction during intranodal migration of T cells}}, doi = {10.1038/s41590-018-0109-z}, volume = {19}, year = {2018}, } @article{2, abstract = {Indirect reciprocity explores how humans act when their reputation is at stake, and which social norms they use to assess the actions of others. A crucial question in indirect reciprocity is which social norms can maintain stable cooperation in a society. Past research has highlighted eight such norms, called “leading-eight” strategies. This past research, however, is based on the assumption that all relevant information about other population members is publicly available and that everyone agrees on who is good or bad. Instead, here we explore the reputation dynamics when information is private and noisy. We show that under these conditions, most leading-eight strategies fail to evolve. Those leading-eight strategies that do evolve are unable to sustain full cooperation.Indirect reciprocity is a mechanism for cooperation based on shared moral systems and individual reputations. It assumes that members of a community routinely observe and assess each other and that they use this information to decide who is good or bad, and who deserves cooperation. When information is transmitted publicly, such that all community members agree on each other’s reputation, previous research has highlighted eight crucial moral systems. These “leading-eight” strategies can maintain cooperation and resist invasion by defectors. However, in real populations individuals often hold their own private views of others. Once two individuals disagree about their opinion of some third party, they may also see its subsequent actions in a different light. Their opinions may further diverge over time. Herein, we explore indirect reciprocity when information transmission is private and noisy. We find that in the presence of perception errors, most leading-eight strategies cease to be stable. Even if a leading-eight strategy evolves, cooperation rates may drop considerably when errors are common. Our research highlights the role of reliable information and synchronized reputations to maintain stable moral systems.}, author = {Hilbe, Christian and Schmid, Laura and Tkadlec, Josef and Chatterjee, Krishnendu and Nowak, Martin}, journal = {PNAS}, number = {48}, pages = {12241--12246}, publisher = {National Academy of Sciences}, title = {{Indirect reciprocity with private, noisy, and incomplete information}}, doi = {10.1073/pnas.1810565115}, volume = {115}, year = {2018}, } @article{5816, abstract = {Solid-state qubit manipulation and read-out fidelities are reaching fault-tolerance, but quantum error correction requires millions of physical qubits and therefore a scalable quantum computer architecture. To solve signal-line bandwidth and fan-out problems, microwave sources required for qubit manipulation might be embedded close to the qubit chip, typically operating at temperatures below 4 K. Here, we perform the first low temperature measurements of a 130 nm BiCMOS based SiGe voltage controlled oscillator at cryogenic temperature. We determined the frequency and output power dependence on temperature and magnetic field up to 5 T and measured the temperature influence on its noise performance. The device maintains its full functionality from 300 K to 4 K. The carrier frequency at 4 K increases by 3% with respect to the carrier frequency at 300 K, and the output power at 4 K increases by 10 dB relative to the output power at 300 K. The frequency tuning range of approximately 20% remains unchanged between 300 K and 4 K. In an in-plane magnetic field of 5 T, the carrier frequency shifts by only 0.02% compared to the frequency at zero magnetic field.}, author = {Hollmann, Arne and Jirovec, Daniel and Kucharski, Maciej and Kissinger, Dietmar and Fischer, Gunter and Schreiber, Lars R.}, issn = {0034-6748}, journal = {Review of Scientific Instruments}, number = {11}, publisher = {AIP Publishing}, title = {{30 GHz-voltage controlled oscillator operating at 4 K}}, doi = {10.1063/1.5038258}, volume = {89}, year = {2018}, }