406 research outputs found

    A second look at gauged supergravities from fluxes in M-theory

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    We investigate reductions of M-theory beyond twisted tori by allowing the presence of KK6 monopoles (KKO6-planes) compatible with N=4 supersymmetry in four dimensions. The presence of KKO6-planes proves crucial to achieve full moduli stabilisation as they generate new universal moduli powers in the scalar potential. The resulting gauged supergravities turn out to be compatible with a weak G2 holonomy at N=1 as well as at some non-supersymmetric AdS4 vacua. The M-theory flux vacua we present here cannot be obtained from ordinary type IIA orientifold reductions including background fluxes, D6-branes (O6-planes) and/or KK5 (KKO5) sources. However, from a four-dimensional point of view, they still admit a description in terms of so-called non-geometric fluxes. In this sense we provide the M-theory interpretation for such non-geometric type IIA flux vacua.Comment: 46 pages. Published version. Minor changes, references adde

    Dirac physical measures on saddle-type fixed points

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    In this article we study some statistical aspects of surface diffeomorphisms. We first show that for a C1C^1 generic diffeomorphism, a Dirac invariant measure whose \emph{statistical basin of attraction} is dense in some open set and has positive Lebesgue measure, must be supported in the orbit of a sink. We then construct an example of a C1C^1-diffeomorphism having a Dirac invariant measure, supported on a hyperbolic fixed point of saddle type, whose statistical basin of attraction is a nowhere dense set with positive Lebesgue measure. Our technique can be applied also to construct a C1C^1 diffeomorphism whose set of points with historic behaviour has positive measure and is nowhere dense.Comment: 63 pages, 26 figures. Final version, accepted in Journal of Dynamics and Differential Equation

    Attractive and repulsive cracks in a heterogeneous material

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    We study experimentally the paths of an assembly of cracks growing in interaction in a heterogeneous two-dimensional elastic brittle material submitted to uniaxial stress. For a given initial crack assembly geometry, we observe two types of crack path. The first one corresponds to a repulsion followed by an attraction on one end of the crack and a tip to tip attraction on the other end. The second one corresponds to a pure attraction. Only one of the crack path type is observed in a given sample. Thus, selection between the two types appears as a statistical collective process.Comment: soumis \`a JSTA

    Neo: an object model for handling electrophysiology data in multiple formats

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    Neuroscientists use many different software tools to acquire, analyze and visualize electrophysiological signals. However, incompatible data models and file formats make it difficult to exchange data between these tools. This reduces scientific productivity, renders potentially useful analysis methods inaccessible and impedes collaboration between labs. A common representation of the core data would improve interoperability and facilitate data-sharing. To that end, we propose here a language-independent object model, named “Neo,” suitable for representing data acquired from electroencephalographic, intracellular, or extracellular recordings, or generated from simulations. As a concrete instantiation of this object model we have developed an open source implementation in the Python programming language. In addition to representing electrophysiology data in memory for the purposes of analysis and visualization, the Python implementation provides a set of input/output (IO) modules for reading/writing the data from/to a variety of commonly used file formats. Support is included for formats produced by most of the major manufacturers of electrophysiology recording equipment and also for more generic formats such as MATLAB. Data representation and data analysis are conceptually separate: it is easier to write robust analysis code if it is focused on analysis and relies on an underlying package to handle data representation. For that reason, and also to be as lightweight as possible, the Neo object model and the associated Python package are deliberately limited to representation of data, with no functions for data analysis or visualization. Software for neurophysiology data analysis and visualization built on top of Neo automatically gains the benefits of interoperability, easier data sharing and automatic format conversion; there is already a burgeoning ecosystem of such tools. We intend that Neo should become the standard basis for Python tools in neurophysiology.EC/FP7/269921/EU/Brain-inspired multiscale computation in neuromorphic hybrid systems/BrainScaleSDFG, 103586207, GRK 1589: Verarbeitung sensorischer Informationen in neuronalen SystemenBMBF, 01GQ1302, Nationaler Neuroinformatik Knote

    Impact of COVID-19 pandemic on Italian Otolaryngology Units: a nationwide study

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    Objective. The aim of this study was to provide an accurate picture of the changes which have occurred during the COVID-19 pandemic, and the contributions given by Italian Otolaryngology Units. Methods. A 29-item questionnaire was completed and returned by 154 Otorhinolaryngology Units across Italy. This investigated their geographic distribution involvement, the main changes which occurred in workload management and in clinical and surgical activities, and the screening procedures for COVID-19 in healthcare personnel and patients. Results. Nearly half of the Otolaryngology Units that responded to the questionnaire were merged with other units, while 22% were converted into COVID-19 units or temporarily closed. A reduction of 8.55% in the number of team members was reported, and about 50% of the units applied uniform work shifts for all staff. Elective activities were uniformly stopped or delayed, passing from 30,295 (pre-COVID data) to 5,684 (COVID data) weekly procedures, with a mean decrease of 81.24% (p<0.001). Conclusions. Most of the elective otolaryngology activities were suspended during the pandemic; the only procedures were for oncology and emergency patients. Italian Otolaryngologists have demonstrated a high availability to collaborate with non-surgery colleagues

    Impact of COVID-19 on otolaryngology in Italy: a commentary from the COVID-19 task force of the young otolaryngologists of the Italian Society of Otolaryngology

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    The ongoing pandemic of coronavirus disease 2019 is having a dramatic effect on most medical disciplines. Otolaryngology Head and Neck Surgery is one of the most engaged disciplines, and otolaryngology specialists are facing a radical change of their role and daily activities that will have severe impact on the return to the ordinary. In this paper, the COVID-19 Task Force of the Young Otolaryngologists of the Italian Society of Otolaryngology comment on the changes that occurred for otolaryngology in Italy during the pandemic with a special focus on the organizational rearrangement of Otolaryngology Units, including merges and closures that affected a significant portion of them; the reallocation of otolaryngology personnel, mainly to COVID-19 wards; the significant reduction of elective clinical and surgical activity, that was mainly limited to oncology and emergency procedures; and the execution of screening procedures for SARS-CoV-2 among healthcare providers and patients in otolaryngology units in Italy

    Measurement of Aerosols at the Pierre Auger Observatory

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    The air fluorescence detectors (FDs) of the Pierre Auger Observatory are vital for the determination of the air shower energy scale. To compensate for variations in atmospheric conditions that affect the energy measurement, the Observatory operates an array of monitoring instruments to record hourly atmospheric conditions across the detector site, an area exceeding 3,000 square km. This paper presents results from four instruments used to characterize the aerosol component of the atmosphere: the Central Laser Facility (CLF), which provides the FDs with calibrated laser shots; the scanning backscatter lidars, which operate at three FD sites; the Aerosol Phase Function monitors (APFs), which measure the aerosol scattering cross section at two FD locations; and the Horizontal Attenuation Monitor (HAM), which measures the wavelength dependence of aerosol attenuation.Comment: Contribution to the 30th International Cosmic Ray Conference, Merida Mexico, July 2007; 4 pages, 4 figure

    Impact of the COVID-19 pandemic on paediatric otolaryngology: a nationwide study

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    Objective: The COVID-19 pandemic profoundly modified the work routine in healthcare; however, its impact on the field of paediatric otorhinolaryngology (ORL) has been rarely investigated. The aim of this study was to assess the impact of COVID-19 on paediatric ORL. Methods: A questionnaire was developed by the Young Otolaryngologists of the Italian Society of ORL-Head and Neck Surgery (GOS). The questionnaire consisted of 26 questions related to workplace and personal paediatric ORL activities. The link was advertised on the official social media platforms and sent by e-mail to 469 Italian otolaryngologists. Results: The questionnaire was completed by 118 responders. During the pandemic, the main reduction was observed for surgical activity (78.8%), followed by outpatient service (16.9%). The conditions that were mostly impacted by a delayed diagnosis were respiratory infections in 45.8% of cases and sensorineural hearing loss in 37.3% of cases. Conclusions: Paediatric ORL was highly impacted by the COVID-19 pandemic, with a significant reduction of surgical and outpatient activities and a delay in time-sensitive diagnosis. Therefore, the implementation of new strategies, such as telemedicine, is recommended

    Non-canonical DNA transcription enzymes and the conservation of two-barrel RNA polymerases

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    DNA transcription depends on multimeric RNA polymerases that are exceptionally conserved in all cellular organisms, with an active site region of >500 amino acids mainly harboured by their Rpb1 and Rpb2 subunits. Together with the distantly related eukaryotic RNA-dependent polymerases involved in gene silencing, they form a monophyletic family of ribonucleotide polymerases with a similarly organized active site region based on two double-Ψ barrels. Recent viral and phage genome sequencing have added a surprising variety of putative nucleotide polymerases to this protein family. These proteins have highly divergent subunit composition and amino acid sequences, but always contain eight invariant amino acids forming a universally conserved catalytic site shared by all members of the two-barrel protein family. Moreover, the highly conserved ‘funnel’ and ‘switch 2’ components of the active site region are shared by all putative DNA-dependent RNA polymerases and may thus determine their capacity to transcribe double-stranded DNA templates
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