Showing papers by "Technical University of Dortmund published in 2017"

Test of lepton universality with B 0 → K *0 ℓ + ℓ − decays

Abstract: A test of lepton universality, performed by measuring the ratio of the branching fractions of the B$^{0}$ → K$^{*0}$ μ$^{+}$ μ$^{−}$ and B$^{0}$ → K$^{*0}$ e$^{+}$ e$^{−}$ decays, $ {R}_{K^{*0}} $ , is presented. The K$^{*0}$ meson is reconstructed in the final state K$^{+}$ π$^{−}$, which is required to have an invariant mass within 100 MeV/c$^{2}$ of the known K$^{*}$(892)$^{0}$ mass. The analysis is performed using proton-proton collision data, corresponding to an integrated luminosity of about 3 fb$^{−1}$, collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. The ratio is measured in two regions of the dilepton invariant mass squared, q$^{2}$, to be $ {R}_{K^{*0}}=\left\{\begin{array}{l}{0.66_{-}^{+}}_{0.07}^{0.11}\left(\mathrm{stat}\right)\pm 0.03\left(\mathrm{syst}\right)\kern1em \mathrm{f}\mathrm{o}\mathrm{r}\kern1em 0.045<{q}^2<1.1\kern0.5em {\mathrm{GeV}}^2/{c}^4,\hfill \\ {}{0.69_{-}^{+}}_{0.07}^{0.11}\left(\mathrm{stat}\right)\pm 0.05\left(\mathrm{syst}\right)\kern1em \mathrm{f}\mathrm{o}\mathrm{r}\kern1em 1.1<{q}^2<6.0\kern0.5em {\mathrm{GeV}}^2/{c}^4.\hfill \end{array}\right. $

Performance of the ATLAS trigger system in 2015

Abstract: During 2015 the ATLAS experiment recorded 3.8 fb(-1) of proton-proton collision data at a centre-of-mass energy of 13 TeV. The ATLAS trigger system is a crucial component of the experiment, respons ...

The IceCube Neutrino Observatory: Instrumentation and Online Systems

Abstract: The IceCube Neutrino Observatory is a cubic-kilometer-scale high-energy neutrino detector built into the ice at the South Pole. Construction of IceCube, the largest neutrino detector built to date, was completed in 2011 and enabled the discovery of high-energy astrophysical neutrinos. We describe here the design, production, and calibration of the IceCube digital optical module (DOM), the cable systems, computing hardware, and our methodology for drilling and deployment. We also describe the online triggering and data filtering systems that select candidate neutrino and cosmic ray events for analysis. Due to a rigorous pre-deployment protocol, 98.4% of the DOMs in the deep ice are operating and collecting data. IceCube routinely achieves a detector uptime of 99% by emphasizing software stability and monitoring. Detector operations have been stable since construction was completed, and the detector is expected to operate at least until the end of the next decade.

Guidelines for the use of flow cytometry and cell sorting in immunological studies

Abstract: The marriage between immunology and cytometry is one of the most stable and productive in the recent history of science. A rapid search in PubMed shows that, as of July 2017, using “flow cytometry immunology” as a search term yields more than 68 000 articles, the first of which, interestingly, is not about lymphocytes. It might be stated that, after a short engagement, the exchange of the wedding rings between immunology and cytometry officially occurred when the idea to link fluorochromes to monoclonal antibodies came about. After this, recognizing different types of cells became relatively easy and feasible not only by using a simple fluorescence microscope, but also by a complex and sometimes esoteric instrument, the flow cytometer that is able to count hundreds of cells in a single second, and can provide repetitive results in a tireless manner. Given this, the possibility to analyse immune phenotypes in a variety of clinical conditions has changed the use of the flow cytometer, which was incidentally invented in the late 1960s to measure cellular DNA by using intercalating dyes, such as ethidium bromide. The epidemics of HIV/AIDS in the 1980s then gave a dramatic impulse to the technology of counting specific cells, since it became clear that the quantification of the number of peripheral blood CD4+ T cells was crucial to follow the course of the infection, and eventually for monitoring the therapy. As a consequence, the development of flow cytometers that had to be easy-to-use in all clinical laboratories helped to widely disseminate this technology. Nowadays, it is rare to find an immunological paper or read a conference abstract in which the authors did not use flow cytometry as the main tool to dissect the immune system and identify its fine and complex functions. Of note, recent developments have created the sophisticated technology of mass cytometry, which is able to simultaneously identify dozens of molecules at the single cell level and allows us to better understand the complexity and beauty of the immune system.

Topological cell clustering in the ATLAS calorimeters and its performance in LHC Run 1

Abstract: The reconstruction of the signal from hadrons and jets emerging from the proton–proton collisions at the Large Hadron Collider (LHC) and entering the ATLAS calorimeters is based on a three-dimensional topological clustering of individual calorimeter cell signals. The cluster formation follows cell signal-significance patterns generated by electromagnetic and hadronic showers. In this, the clustering algorithm implicitly performs a topological noise suppression by removing cells with insignificant signals which are not in close proximity to cells with significant signals. The resulting topological cell clusters have shape and location information, which is exploited to apply a local energy calibration and corrections depending on the nature of the cluster. Topological cell clustering is established as a well-performing calorimeter signal definition for jet and missing transverse momentum reconstruction in ATLAS.

Childhood maltreatment and characteristics of adult depression: meta-analysis.

Abstract: Background Childhood maltreatment has been discussed as a risk factor for the development and maintenance of depression. Aims To examine the relationship between childhood maltreatment and adult depression with regard to depression incidence, severity, age at onset, course of illness and treatment response. Method We conducted meta-analyses of original articles reporting an association between childhood maltreatment and depression outcomes in adult populations. Results In total, 184 studies met inclusion criteria. Nearly half of patients with depression reported a history of childhood maltreatment. Maltreated individuals were 2.66 (95% CI 2.38–2.98) to 3.73 (95% CI 2.88–4.83) times more likely to develop depression in adulthood, had an earlier depression onset and were twice as likely to develop chronic or treatment-resistant depression. Depression severity was most prominently linked to childhood emotional maltreatment. Conclusions Childhood maltreatment, especially emotional abuse and neglect, represents a risk factor for severe, early-onset, treatment-resistant depression with a chronic course.

Observation of the Doubly Charmed Baryon Ξcc

Abstract: A highly significant structure is observed in the Λc+K-π+π+ mass spectrum, where the Λc+ baryon is reconstructed in the decay mode pK-π+. The structure is consistent with originating from a weakly decaying particle, identified as the doubly charmed baryon Ξcc++. The difference between the masses of the Ξcc++ and Λc+ states is measured to be 1334.94±0.72(stat.)±0.27(syst.) MeV/c2, and the Ξcc++ mass is then determined to be 3621.40±0.72(stat.)±0.27(syst.)±0.14(Λc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Λc+ mass. The state is observed in a sample of proton-proton collision data collected by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.7 fb-1, and confirmed in an additional sample of data collected at 8 TeV.

When Recurrent Neural Networks meet the Neighborhood for Session-Based Recommendation

Abstract: Deep learning methods have led to substantial progress in various application fields of AI, and in recent years a number of proposals were made to improve recommender systems with artificial neural networks. For the problem of making session-based recommendations, i.e., for recommending the next item in an anonymous session, Hidasi et al.~recently investigated the application of recurrent neural networks with Gated Recurrent Units (GRU4REC). Assessing the true effectiveness of such novel approaches based only on what is reported in the literature is however difficult when no standard evaluation protocols are applied and when the strength of the baselines used in the performance comparison is not clear. In this work we show based on a comprehensive empirical evaluation that a heuristics-based nearest neighbor (kNN) scheme for sessions outperforms GRU4REC in the large majority of the tested configurations and datasets. Neighborhood sampling and efficient in-memory data structures ensure the scalability of the kNN method. The best results in the end were often achieved when we combine the kNN approach with GRU4REC, which shows that RNNs can leverage sequential signals in the data that cannot be detected by the co-occurrence-based kNN method.

Search for new high-mass phenomena in the dilepton final state using 36 fb−1 of proton-proton collision data at √s=13 TeV with the ATLAS detector

Abstract: A search is conducted for new resonant and non-resonant high-mass phenomena in dielectron and dimuon fi nal states. The search uses 36 : 1 fb(-1) of proton-proton collision data, collected at root ...

Activating the molecular spinterface.

Abstract: This Perspective discusses the spin-dependent properties emerging at the interfaces of molecular and inorganic materials, and describes possible future developments for spin-based technologies. The miniaturization trend in the semiconductor industry has led to the understanding that interfacial properties are crucial for device behaviour. Spintronics has not been alien to this trend, and phenomena such as preferential spin tunnelling, the spin-to-charge conversion due to the Rashba–Edelstein effect and the spin–momentum locking at the surface of topological insulators have arisen mainly from emergent interfacial properties, rather than the bulk of the constituent materials. In this Perspective we explore inorganic/molecular interfaces by looking closely at both sides of the interface. We describe recent developments and discuss the interface as an ideal platform for creating new spin effects. Finally, we outline possible technologies that can be generated thanks to the unique active tunability of molecular spinterfaces.

All-sky Search for Time-integrated Neutrino Emission from Astrophysical Sources with 7 yr of IceCube Data

Abstract: Since the recent detection of an astrophysical flux of high-energy neutrinos, the question of its origin has not yet fully been answered. Much of what is known about this flux comes from a small ev ...

Leadership, followers' mental health and job performance in organizations: A comprehensive meta-analysis from an occupational health perspective

Abstract: Summary The present meta-analysis investigates the associations between leadership, followers' mental health, and job performance by taking into account different groups of leadership constructs including transformational leadership, relations-oriented leadership, task-oriented leadership, destructive leadership, and leader–member exchange. Six categories of mental health-related outcomes are considered representing both negative and positive mental health states of followers, namely, affective symptoms, burnout, stress, well-being, psychological functioning, and health complaints. Meta-analytic models are used to estimate the association between these categories of leadership and mental health. Our results reveal that transformational leadership, a high quality of relations-oriented and task-oriented leadership behavior, as well as a high quality of leader–follower interaction are positively associated with mental health. In contrast, destructive leadership is strongly negatively associated with mental health. In addition, the mediation effects of leadership on job performance via mental health are estimated. Results partially support the mediating role of mental health concerning the relationship between leadership and job performance. Our results emphasize the importance of leadership as an occupational health factor, and they may serve as basis for the planning and designing of occupational health policies and interventions despite existing research limitations. Copyright © 2016 John Wiley & Sons, Ltd.

The contribution of fermi-2lac blazars to diffuse tev-pev neutrino flux

Abstract: M. G. Aartsen, K. Abraham, M. Ackermann, J. Adams, J. A. Aguilar, M. Ahlers, M. Ahrens, D. Altmann, K. Andeen, T. Anderson, I. Ansseau, G. Anton, M. Archinger, C. Arguelles, T. C. Arlen, J. Auffenberg, S. Axani, X. Bai, S. W. Barwick, V. Baum, R. Bay, J. J. Beatty, J. Becker Tjus, K.-H. Becker, S. BenZvi, P. Berghaus, D. Berley, E. Bernardini, A. Bernhard, D. Z. Besson, G. Binder, D. Bindig, M. Bissok, E. Blaufuss, S. Blot, D. J. Boersma, C. Bohm, M. Borner, F. Bos, D. Bose, S. Boser, O. Botner, J. Braun, L. Brayeur, H.-P. Bretz, A. Burgman, J. Casey, M. Casier, E. Cheung, D. Chirkin, A. Christov, K. Clark, L. Classen, S. Coenders, G. H. Collin, J. M. Conrad, D. F. Cowen, A. H. Cruz Silva, J. Daughhetee, J. C. Davis, M. Day, J. P. A. M. de Andre, C. De Clercq, E. del Pino Rosendo, H. Dembinski, S. De Ridder, P. Desiati, K. D. de Vries, G. de Wasseige, M. de With, T. DeYoung, J. C. Diaz-Velez, V. di Lorenzo, H. Dujmovic, J. P. Dumm, M. Dunkman, B. Eberhardt, T. Ehrhardt, B. Eichmann, S. Euler, P. A. Evenson, S. Fahey, A. R. Fazely, J. Feintzeig, J. Felde, K. Filimonov, C. Finley, S. Flis, C.-C. Fosig, A. Franckowiak, T. Fuchs, T. K. Gaisser, R. Gaior, J. Gallagher, L. Gerhardt, K. Ghorbani, W. Giang, L. Gladstone, M. Glagla, T. Glusenkamp, A. Goldschmidt, G. Golup, J. G. Gonzalez, D. GOra, D. Grant, Z. Griffith, C. Haack, A. Haj Ismail, A. Hallgren, F. Halzen, E. Hansen, B. Hansmann, T. Hansmann, K. Hanson, D. Hebecker, D. Heereman, K. Helbing, R. Hellauer, S. Hickford, J. Hignight, G. C. Hill, K. D. Hoffman, R. Hoffmann, K. Holzapfel, A. Homeier, K. Hoshina, F. Huang, M. Huber, W. Huelsnitz, K. Hultqvist, S. In, A. Ishihara, E. Jacobi, G. S. Japaridze, M. Jeong, K. Jero, B. J. P. Jones, M. Jurkovic, A. Kappes, T. Karg, A. Karle, U. Katz, M. Kauer, A. Keivani, J. L. Kelley, J. Kemp, A. Kheirandish, M. Kim, T. Kintscher, J. Kiryluk, T. Kittler, S. R. Klein, G. Kohnen, R. Koirala, H. Kolanoski, R. Konietz, L. Kopke, C. Kopper, S. Kopper, D. J. Koskinen, M. Kowalski, K. Krings, M. Kroll, G. Kruckl, C. Kruger, J. Kunnen, S. Kunwar, N. Kurahashi, T. Kuwabara, M. Labare, J. L. Lanfranchi, M. J. Larson, D. Lennarz, M. Lesiak-Bzdak, M. Leuermann, J. Leuner, L. Lu, J. Lunemann, J. Madsen, G. Maggi, K. B. M. Mahn, S. Mancina, M. Mandelartz, R. Maruyama, K. Mase, R. Maunu, F. McNally, K. Meagher, M. Medici, M. Meier, A. Meli, T. Menne, G. Merino, T. Meures, S. Miarecki, E. Middell, L. Mohrmann, T. Montaruli, M. Moulai, R. Nahnhauer, U. Naumann, G. Neer, H. Niederhausen, S. C. Nowicki, D. R. Nygren, A. Obertacke Pollmann, A. Olivas, A. Omairat, A. O, Murchadha, T. Palczewski, H. Pandya, D. V. Pankova, O. Penek, J. A. Pepper, C. Perez de los Heros, C. Pfendner, D. Pieloth, E. Pinat, J. Posselt, P. B. Price, G. T. Przybylski, M. Quinnan, C. Raab, L. Radel, M. Rameez, K. Rawlins, R. Reimann, M. Relich, E. Resconi, W. Rhode, M. Richman, B. Riedel, S. Robertson, M. Rongen, C. Rott, T. Ruhe, D. Ryckbosch, D. Rysewyk, L. Sabbatini, S. E. Sanchez Herrera, A. Sandrock, J. Sandroos, S. Sarkar, K. Satalecka, M. Schimp, P. Schlunder, T. Schmidt, S. Schoenen, S. Schoneberg, A. Schonwald, L. Schumacher, D. Seckel, S. Seunarine, D. Soldin, M. Song, G. M. Spiczak, C. Spiering, M. Stahlberg, M. Stamatikos, T. Stanev, A. Stasik, A. Steuer, T. Stezelberger, R. G. Stokstad, A. Stosl, R. Strom, N. L. Strotjohann, G. W. Sullivan, M. Sutherland, H. Taavola, I. Taboada, J. Tatar, S. Ter-Antonyan, A. Terliuk, G. TesiC, S. Tilav, P. A. Toale, M. N. Tobin, S. Toscano, D. Tosi, M. Tselengidou, A. Turcati, E. Unger, M. Usner, S. Vallecorsa, J. Vandenbroucke, N. van Eijndhoven, S. Vanheule, M. van Rossem, J. van Santen, J. Veenkamp, M. Vehring, M. Voge, M. Vraeghe, C. Walck, A. Wallace, M. Wallraff, N. Wandkowsky, Ch. Weaver, C. Wendt, S. Westerhoff, B. J. Whelan, S. Wickmann, K. Wiebe, C. H. Wiebusch, L. Wille, D. R. Williams, L. Wills, H. Wissing, M. Wolf, T. R. Wood, E. Woolsey, K. Woschnagg, D. L. Xu, X. W. Xu, Y. Xu, J. P. Yanez, G. Yodh, S. Yoshida and M. Zoll (IceCube Collaboration)

Adverse outcome pathways: opportunities, limitations and open questions.

Abstract: Adverse outcome pathways (AOPs) are a recent toxicological construct that connects, in a formalized, transparent and quality-controlled way, mechanistic information to apical endpoints for regulatory purposes. AOP links a molecular initiating event (MIE) to the adverse outcome (AO) via key events (KE), in a way specified by key event relationships (KER). Although this approach to formalize mechanistic toxicological information only started in 2010, over 200 AOPs have already been established. At this stage, new requirements arise, such as the need for harmonization and re-assessment, for continuous updating, as well as for alerting about pitfalls, misuses and limits of applicability. In this review, the history of the AOP concept and its most prominent strengths are discussed, including the advantages of a formalized approach, the systematic collection of weight of evidence, the linkage of mechanisms to apical end points, the examination of the plausibility of epidemiological data, the identification of critical knowledge gaps and the design of mechanistic test methods. To prepare the ground for a broadened and appropriate use of AOPs, some widespread misconceptions are explained. Moreover, potential weaknesses and shortcomings of the current AOP rule set are addressed (1) to facilitate the discussion on its further evolution and (2) to better define appropriate vs. less suitable application areas. Exemplary toxicological studies are presented to discuss the linearity assumptions of AOP, the management of event modifiers and compensatory mechanisms, and whether a separation of toxicodynamics from toxicokinetics including metabolism is possible in the framework of pathway plasticity. Suggestions on how to compromise between different needs of AOP stakeholders have been added. A clear definition of open questions and limitations is provided to encourage further progress in the field.

$R_K$ and $R_{K^{\ast}}$ beyond the Standard Model

Abstract: Measurements of the ratio of $B\ensuremath{\rightarrow}{K}^{*}\ensuremath{\mu}\ensuremath{\mu}$ to $B\ensuremath{\rightarrow}{K}^{*}ee$ branching fractions, ${R}_{{K}^{*}}$, by the LHCb Collaboration strengthen the hints from previous studies with pseudoscalar kaons, ${R}_{K}$, for the breakdown of lepton universality, and therefore the Standard Model (SM), to $\ensuremath{\sim}3.5\ensuremath{\sigma}$. Complementarity between ${R}_{K}$ and ${R}_{{K}^{*}}$ allows us to pin down the Dirac structure of the new contributions to be predominantly SM-like chiral, with possible admixture of chirality-flipped contributions of up to $\mathcal{O}(\mathrm{few}10%)$. Scalar and vector leptoquark representations $({S}_{3},{V}_{1},{V}_{3})$ plus possible (${\stackrel{\texttildelow{}}{S}}_{2},{V}_{2}$) admixture can explain ${R}_{K,{K}^{*}}$ via tree-level exchange. Flavor models naturally predict leptoquark masses not exceeding a few TeV, with couplings to third-generation quarks at $O(0.1)$, implying that this scenario can be directly tested at the LHC.

General Enantioselective C-H Activation with Efficiently Tunable Cyclopentadienyl Ligands.

Abstract: Cyclopentadienyl (Cp) ligands enable efficient steering of various transition-metal-catalyzed transformations, in particular enantioselective C−H activation. Currently only few chiral Cp ligands are available. Therefore, a conceptually general approach to chiral Cp ligand discovery would be invaluable as it would enable the discovery of applicable Cp ligands and to efficiently and rapidly vary and tune their structures. Herein, we describe the three-step gram-scale synthesis of a structurally diverse and widely applicable chiral Cp ligand collection (JasCp ligands) with highly variable and adjustable structures. Their modular nature and their amenability to rapid structure variation enabled the efficient discovery of ligands for three enantioselective RhIII-catalyzed C−H activation reactions, including one unprecedented transformation. This novel approach should enable the discovery of efficient chiral Cp ligands for various further enantioselective transformations.

Hot isostatic pressing of IN718 components manufactured by selective laser melting

Abstract: Selective laser melting and other additive manufacturing (AM) techniques have recently attracted substantial interest of both researchers and the processing industry. The freedom of design leads to completely new possibilities for constructions and, thus, to entirely new products. In the selective laser melting (SLM) process, the components are produced layer-wise using a laser beam. SLM is a powder bed based AM process and is characterized by the complete melting of the utilized powder material. Employing SLM, complex three-dimensional parts and light weight structures can be produced directly from 3D CAD data. However, although SLM is a very promising technology, there are still challenges to solve. In the present study, a close look is taken at the porosity. Under cyclic loading, pores can act as stress raisers and lead to premature crack initiations, which reduce the fatigue strength of the material. Hot isostatic pressing (HIP) offers the possibility to reduce the porosity. HIP combines high pressure and high temperature to produce materials with superior properties. The influence of the HIP process parameters on the density and microstructure of IN718 SLM components is investigated by means of micro X-ray computed tomography and scanning electron microscopy. The results of the experiments show that the majority of pores can be densified by means of HIP. On the other hand, some pores cannot be densified. The reason for this is seen in entrapped argon gas from the SLM process.

Observation of Five New Narrow Ω_{c}^{0} States Decaying to Ξ_{c}^{+}K^{-}

Abstract: The Ξ_{c}^{+}K^{-} mass spectrum is studied with a sample of pp collision data corresponding to an integrated luminosity of 3.3 fb^{-1}, collected by the LHCb experiment. The Ξ_{c}^{+} is reconstructed in the decay mode pK^{-}π^{+}. Five new, narrow excited Ω_{c}^{0} states are observed: the Ω_{c}(3000)^{0}, Ω_{c}(3050)^{0}, Ω_{c}(3066)^{0}, Ω_{c}(3090)^{0}, and Ω_{c}(3119)^{0}. Measurements of their masses and widths are reported.

Search for annihilating dark matter in the Sun with 3 years of IceCube data

Abstract: We present results from an analysis looking for darkmatter annihilation in the Sun with the IceCube neutrino telescope. Gravitationally trapped dark matter in the Sun's core can annihilate into Sta ...

The Health Effects of Aluminum Exposure.

Abstract: Background Aluminum is regularly taken up with the daily diet. It is also used in antiperspirants, as an adjuvant for vaccination, and in desensitization procedures. In this review, we present the scientifically documented harmful effects of aluminum on health and the threshold values associated with them.

Observation of J/psi phi Structures Consistent with Exotic States from Amplitude Analysis of B+ -> J/psi phi K+ Decays

Abstract: The first full amplitude analysis of B+→J/ψϕK+ with J/ψ→μ+μ−, ϕ→K+K− decays is performed with a data sample of 3 fb−1 of pp collision data collected at s√=7 and 8 TeV with the LHCb detector. The data cannot be described by a model that contains only excited kaon states decaying into ϕK+, and four J/ψϕ structures are observed, each with significance over 5 standard deviations. The quantum numbers of these structures are determined with significance of at least 4 standard deviations. The lightest is best described as a D±sD∗∓s cusp, but a resonant interpretation is also possible with mass consistent with, but width much larger than, previous measurements of the claimed X(4140) state.

Differentiation of cardiomyocytes and generation of human engineered heart tissue

Abstract: Since the advent of the generation of human induced pluripotent stem cells (hiPSCs), numerous protocols have been developed to differentiate hiPSCs into cardiomyocytes and then subsequently assess their ability to recapitulate the properties of adult human cardiomyocytes. However, hiPSC-derived cardiomyocytes (hiPSC-CMs) are often assessed in single-cell assays. A shortcoming of these assays is the limited ability to characterize the physiological parameters of cardiomyocytes, such as contractile force, due to random orientations. This protocol describes the differentiation of cardiomyocytes from hiPSCs, which occurs within 14 d. After casting, cardiomyocytes undergo 3D assembly. This produces fibrin-based engineered heart tissues (EHTs)-in a strip format-that generate force under auxotonic stretch conditions. 10-15 d after casting, the EHTs can be used for contractility measurements. This protocol describes parallel expansion of hiPSCs; standardized generation of defined embryoid bodies, growth factor and small-molecule-based cardiac differentiation; and standardized generation of EHTs. To carry out the protocol, experience in advanced cell culture techniques is required.

Cation–Anion Arrangement Patterns in Self-Assembled Pd2L4 and Pd4L8 Coordination Cages

Abstract: ConspectusCompounds featuring one-dimensional regular arrangements of stacked metal complexes and alternating [cation–anion]∞ sequences have raised considerable interest owing to their peculiar electronic and optical properties as well as guest inclusion capabilities. While traditional ways to realize these structural motifs rely on crystalline compounds, exclusively existing in the solid state, recent progress in the area of metal-mediated supramolecular self-assembly allows for the rational synthesis of structurally well-defined short stretches of stacked metal complexes and cation–anion arrangements. Therefore, metal cations, counteranions, and suitably designed organic bridges are allowed to self-assemble in solution. While the bridges can be designed as cross-linkers to yield extended two- or three-dimensional networks such as layered materials, metal–organic frameworks (MOFs), or porous coordination polymers (PCPs), they can also be tailored to lead to discrete nanoscopic objects. Supramolecular hel...

The large enriched germanium experiment for neutrinoless double beta decay (LEGEND)

Abstract: The observation of neutrinoless double-beta decay (0νββ) would show that lepton number is violated, reveal that neu-trinos are Majorana particles, and provide information on neutrino mass. A discovery-capable experiment covering the inverted ordering region, with effective Majorana neutrino masses of 15 - 50 meV, will require a tonne-scale experiment with excellent energy resolution and extremely low backgrounds, at the level of ∼0.1 count /(FWHM·t·yr) in the region of the signal. The current generation 76Ge experiments GERDA and the Majorana Demonstrator, utilizing high purity Germanium detectors with an intrinsic energy resolution of 0.12%, have achieved the lowest backgrounds by over an order of magnitude in the 0νββ signal region of all 0νββ experiments. Building on this success, the LEGEND collaboration has been formed to pursue a tonne-scale 76Ge experiment. The collaboration aims to develop a phased 0νββ experimental program with discovery potential at a half-life approaching or at 1028 years, using existing resources as appropriate to expedite physics results.