Towards the Holographic Dual of N = 2 SYK

The gravitational part of the holographic dual to the SYK model has been conjectured to be Jackiw-Teitelboim (JT) gravity. In this paper we construct an AdS2 background in N = (2,2) JT gravity and show that the gravitational dynamics are - as in the N = 0 and N = 1 cases - fully captured by the extrinsic curvature as an effective boundary action. This boundary term is given by the super-Schwarzian of the N = 2 SYK model, thereby providing further evidence of the JT/SYK duality. The chirality of this SYK model is reproduced by the inherent chirality of axial N = (2,2) supergravity.Comment: 22 pages,v2 references added, typos correcte

Reannihilation of self-interacting dark matter

We explore the phenomenology of having a second epoch of dark matter annihilation into dark radiation long after the standard thermal freeze-out. Such a hidden reannihilation process could affect visible sectors only gravitationally. As a concrete realization we consider self-interacting dark matter (SIDM) with a light force mediator coupled to dark radiation. We demonstrate how resonantly Sommerfeld enhanced cross sections emerge to induce the reannihilation epoch. The effect is a temporally local modification of the Hubble expansion rate and we show that the Cosmic Microwave Background (CMB) measurements -- as well as other observations -- have a high sensitivity to observe this phenomenon. Special attention is given to the model region where late kinetic decoupling and strong self-interactions can alleviate several small-scale problems in the cold dark matter paradigm at the same time. Interestingly, we find that reannihilation might here also simultaneously lower the tension between CMB and low-redshift astronomical observations of $H_{0}$ and $\sigma_{8}$. Moreover, we identify reannihilation as a clear signature to discriminate between the phenomenologically otherwise almost identical vector and scalar mediator realizations of SIDM.Comment: Version submitted to journal. Extended with improved estimates and updated plots. 25 pages, 9 figures and 2 table

Overview about Service Labs worldwide: Approaches, Methods and Use Cases to test Service across Lifecycle

AbstractAs product-service systems are very complex, an integrated approach how to test a service is needed. The paper provides a framework for the development and testing of new services, and thereby grants a lot of space and tools for service innovation. In product-service-systems different types of resources are involved, for instance people, technology, information and organization. In the framework provided by mixed reality laboratory environments, all of these resources are brought together as well. The resources people, technology, information and organization are integrated. The interdisciplinary knowledge concerning these relevant resources is merged in the laboratory environments. Furthermore mixed reality laboratory environments are unifying academic expertise and practical, business-driven interests. Since service relevance in manufacturing companies is growing, the testing of new service concepts gets more important. Various methods are available, which help to verify service concepts. Due to this, the focus of this paper is on the analysis of established Service and Innovation Labs worldwide. To give an overview 24 Service labs are identified and analysed

Percutaneous posterolateral approach for the simulation of a far-lateral disc herniation in an ovine model

This work describes a minimally invasive damage model for ovine lumbar discs via partial nucleotomy using a posterolateral approach. Two cadavers were dissected to analyze the percutaneous corridor. Subsequently, 28 ovine had their annulus fibrosus punctured via awl penetration under fluoroscopic control and nucleus pulposus tissue removed via rongeur. Efficacy was assessed by animal morbidity, ease of access to T12-S1 disc spaces, and production of a mechanical injury as verified by discography, radiography, and histology. T12-S1 were accessible with minimal nerve damage morbidity. Scar tissue sealed the disc puncture site in all animals within 6 weeks, withstanding 1 MP of intradiscal pressure. Partial nucleotomy led to a significant reduction in intervertebral disk height and an increased histological degeneration score. Inducing a reproducible injury pattern of disc degeneration required minimal time, effort, and equipment. The posterolateral approach allows operation on several discs within a single surgery and multiple animal surgeries within a single day.Peer reviewe

Synthesis and characterization of rigid [2.2]paracyclophane-porphyrin conjugates as scaffolds for fixed-distance bimetallic complexes

This work presents a new approach to prepare mono- and disubstituted linear rigid bimetallic [2.2]paracyclophane-porphyrin conjugates via palladium-mediated Stille cross-coupling reaction. The metalated porphyrin moiety can be varied allowing convenient access to modular metal-metal fixed-distance Cu/Zn complexes.Peer reviewe

Cardiorespiratory Fitness and Insulin Sensitivity in Overweight or Obese Subjects May Be Linked Through Intrahepatic Lipid Content

Objective: Low cardiorespiratory fitness predisposes to cardiovascular disease and type 2 diabetes mellitus in part independently of body weight. Given the close relationship between intrahepatic lipid content (IHL) and insulin sensitivity, we hypothesized that the direct relationship between fitness and insulin sensitivity may be explained by IHL. Research Design and Methods: We included 138 overweight to obese, otherwise healthy subjects (age: 43.6 +/- 8.9 yrs., body mass index: 33.8 +/- 4 kg/m(2)). Body composition was estimated by bio-impedance analyses. Abdominal fat distribution, intramyocellular, and intrahepatic lipid content were assessed by magnetic resonance spectroscopy and tomography. Incremental exercise testing was performed to estimate individual's cardiorespiratory fitness. Insulin sensitivity was determined during an oral glucose tolerance test. Results: For all subjects, cardiorespiratory fitness was related to insulin sensitivity (r=0.32, p<0.05), IHL (r=-0.27, p<0.05), visceral (r=-0.25, p<0.05) and total fat mass (r=-0.32, p<0.05), but not to intramyocellular lipids (r=-0.08, ns). Insulin sensitivity correlated significantly with all fat depots. In multivariate regression analyses, independent predictors of insulin sensitivity were IHL, visceral fat and fitness (r(2)=-0.43, p<0.01; r(2)=-0.34 and r(2)=0.29, p<0.05, respectively). However, the positive correlation between fitness and insulin sensitivity was abolished after adjustment for IHL (r=0.16, ns), whereas it remained significant when adjusted for visceral- or total body fat. Further, when subjects were grouped into high versus low IHL, insulin sensitivity was higher in those subjects with low IHL, irrespective of fitness levels. Conclusions: Our study suggests that the positive effect of increased cardiorespiratory fitness in overweight to obese subjects on insulin sensitivity may be mediated indirectly through IHL reduction

Self-Cleaning Antireflective Optical Coatings

Low-cost antireflection coatings (ARCs) on large optical surfaces are an ingredient-technology for high-performance solar cells. While nanoporous thin films that meet the zero-reflectance conditions on transparent substrates can be cheaply manufactured, their suitability for outdoor applications is limited by the lack of robustness and cleanability. Here, we present a simple method for the manufacture of robust self-cleaning ARCs. Our strategy relies on the self-assembly of a block-copolymer in combination with silica-based sol–gel chemistry and preformed TiO2 nanocrystals. The spontaneous dense packing of copolymer micelles followed by a condensation reaction results in an inverse opal-type silica morphology that is loaded with TiO2 photocatalytic hot-spots. The very low volume fraction of the inorganic network allows the optimization of the antireflecting properties of the porous ARC despite the high refractive index of the embedded photocatalytic TiO2 nanocrystals. The resulting ARCs combine high optical and self-cleaning performance and can be deposited onto flexible plastic substrates

Advances in Production Management Systems: Issues, Trends, and Vision Towards 2030

Since its inception in 1978, the IFIP Working Group (WG) 5.7 on Advances in Production Management Systems (APMS) has played an active role in the fields of production and production management. The Working Group has focused on the conception, development, strategies, frameworks, architectures, processes, methods, and tools needed for the advancement of both fields. The associated standards created by the IFIP WG5.7 have always been impacted by the latest developments of scientific rigour, academic research, and industrial practices. The most recent of those developments involves the Fourth Industrial Revolution, which is having remarkable (r)evolutionary and disruptive changes in both the fields and the standards. These changes are triggered by the fusion of advanced operational and informational technologies, innovative operating and business models, as well as social and environmental pressures for more sustainable production systems. This chapter reviews past, current, and future issues and trends to establish a coherent vision and research agenda for the IFIP WG5.7 and its international community. The chapter covers a wide range of production aspects and resources required to design, engineer, and manage the next generation of sustainable and smart production systems.acceptedVersio