Universal Kounterterms in Lovelock AdS gravity

We show the universal form of the boundary term (Kounterterm series) which regularizes the Euclidean action and background-independent definition of conserved quantities for any Lovelock gravity theory with AdS asymptotics (including Einstein-Hilbert and Einstein-Gauss-Bonnet). We discuss on the connection of this procedure to the existence of topological invariants and Chern-Simons forms in the corresponding dimensions.Comment: 9 pages, no figures. Contribution to the proceedings of 3rd RTN Workshop: Constituents, Fundamental Forces and Symmetries of the Universe, Valencia, Spain, 1-5 Oct 200

Dynamical Structure of Irregular Constrained Systems

Hamiltonian systems with functionally dependent constraints (irregular systems), for which the standard Dirac procedure is not directly applicable, are discussed. They are classified according to their behavior in the vicinity of the constraint surface into two fundamental types. If the irregular constraints are multilinear (type I), then it is possible to regularize the system so that the Hamiltonian and Lagrangian descriptions are equivalent. When the constraints are power of a linear function (type II), regularization is not always possible and the Hamiltonian and Lagrangian descriptions may be dynamically inequivalent. It is shown that the inequivalence between the two formalisms can occur if the kinetic energy is an indefinite quadratic form in the velocities. It is also shown that a system of type I can evolve in time from a regular configuration into an irregular one, without any catastrophic changes. Irregularities have important consequences in the linearized approximation to nonlinear theories, as well as for the quantization of such systems. The relevance of these problems to Chern-Simons theories in higher dimensions is discussed.Comment: 14 pages, no figures, references added. Final version for J. Math. Phy

Electronic Excitations in Graphene in the 1–50 eV Range: The π and π + σ Peaks Are Not Plasmons

The field of plasmonics relies on light coupling strongly to plasmons as collective excitations. The energy loss function of graphene is dominated by two peaks at ∼5 and ∼15 eV, known as π and π + σ plasmons, respectively. We use electron energy-loss spectroscopy in an aberration-corrected scanning transmission electron microscope and density functional theory to show that between 1 to 50 eV, these prominent π and π + σ peaks are not plasmons, but single-particle interband excitations

Need for ICU and outcome of critically ill patients with COVID-19 and haematological malignancies: results from the EPICOVIDEHA survey

The risk for a severe coronavirus disease 2019 (COVID-19) with need for an intensive care unit (ICU) admission in a non-immunocompromised vaccinated population dropped from 5% at the beginning of the pandemic to at least 0.2% and is still decreasing since the omicron strain dominates the COVID-19 pandemic [1]. Beyond the risk factors identified for a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection like male sex, older age, and comorbidities such as cardiovascular disease, lung disease or obesity, patients with a history of malignancy, specifically patients with haematological malignancy, are prone to develop a complicated SARS-CoV-2 infection with need for ICU which is still associated with poorer clinical outcome [2,3,4,5,6,7,8,9,10,11,12,13,14,15]. The circumstances of a widely heterogenous population with regards to the type of haematological malignancy, extent of disease, haematological malignancy treatment history, [16,17,18] and baseline performance status are even more challenging in the environment of an ICU [19]. Although, data referring to critically ill COVID-19 patients regarding treatment strategies and outcome are widely available, data referring to critically ill patients with haematological malignancy are scarce and underreported [20]. The aim of this study is to analyze the epidemiology, risk factors and outcome of patients with haematological malignancy with need for an ICU setting using the data from the large-scale EPICOVIDEHA registry of the European Hematology Association—Scientific Working Group Infectious in Hematology (EHA-SWG) [21].Open Access funding enabled and organized by Projekt DEAL. EPICOVIDEHA has received funds from Optics COMMIT (COVID-19 Unmet Medical Needs and Associated Research Extension) COVID-19 RFP program by GILEAD Science, United States (Project 2020-8223).Peer reviewe