8,475 research outputs found

    Principles of generalization for sensorimotor cerebellar learning

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    Measurement of the H → γ γ and H → ZZ∗ → 4 cross-sections in pp collisions at √s = 13.6 TeV with the ATLAS detector

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    The inclusive Higgs boson production cross section is measured in the di-photon and the Z Z∗ → 4 decay channels using 31.4 and 29.0 fb−1 of pp collision data respectively, collected with the ATLAS detector at a centre of-mass energy of √s = 13.6 TeV. To reduce the model dependence, the measurement in each channel is restricted to a particle-level phase space that closely matches the chan nel’s detector-level kinematic selection, and it is corrected for detector effects. These measured fiducial cross-sections are σfid,γ γ = 76+14 −13 fb, and σfid,4 = 2.80 ± 0.74 fb, in agreement with the corresponding Standard Model predic tions of 67.6±3.7 fb and 3.67±0.19 fb. Assuming Standard Model acceptances and branching fractions for the two chan nels, the fiducial measurements are extrapolated to the full phase space yielding total cross-sections of σ (pp → H) = 67+12 −11 pb and 46±12 pb at 13.6 TeV from the di-photon and Z Z∗ → 4 measurements respectively. The two measure ments are combined into a total cross-section measurement of σ (pp → H) = 58.2±8.7 pb, to be compared with the Stan dard Model prediction of σ (pp → H)SM = 59.9 ± 2.6 p

    Mineral snowflakes on exoplanets and brown dwarfs

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    The diversity of exoplanets and brown dwarfs provides ideal atmospheric laboratories to investigate novel physico-chemical regimes. Furthermore, the atmospheres of exoplanets act as the history books of planetary system. However, as observational data improves, the contributions of cloud particles in exoplanet and brown dwarf atmospheres must be adequately accounted for. Microphysical modelling of cloud formation provides the best method to investigate the potentially observable properties of clouds in these atmospheres. Most observed gas-giant exoplanets have been suggested to host mineral clouds which could form `snowflake-like' structures through condensation and constructive collisions. Cloud particle porosity, size and number density are influenced by constructive and destructive collisions. In this thesis, we expand our kinetic non-equilibrium cloud formation model to explore the effects of non-compact, non-spherical cloud particles on cloud structure and their spectroscopic properties. Additionally, we investigate the effects on clouds of collisional growth and fragmentation. The impact of these affects is assessed on prescribed 1D (Tgas-Pgas) profiles in DRIFT-PHOENIX model atmospheres of brown dwarfs and exoplanets. We utilise Mie theory and effective medium theory to study cloud optical depths, where we additionally represent non-spherical cloud particles with a statistical distribution of hollow spheres. We find that micro-porosity can affect the distribution of cloud particles in an exoplanet atmosphere, and that irregular particle shape impacts the optical depth in the near- and mid-infrared. However, we also find that cloud particle collisions driven by turbulence result in fragmentation of cloud particles for exoplanet atmospheres, which also impacts optical depths in the optical and mid-infrared regions. The global distribution and properties of clouds is also important as observations begin to allow for treating exoplanets in their full 3D nature. We therefore apply a hierarchical approach to global cloud formation modelling. We also apply our 1D cloud formation model to profiles extracted from results of 3D General Circulation Models (GCM) for the gas-giant exoplanet WASP-43b and the ultra-hot Jupiter HAT-P-7b, revealing a dramatic difference in the distribution of clouds between these types of exoplanets as a result of stellar radiation heating the day-side of the ultra-hot planets. This results in an asymmetry in cloud structures for the terminators of WASP-43b and more significantly for HAT-P-7b, observable in the optical depth of the clouds at these points, further complicating retrieval of cloud properties from spectra."This work was supported by the Science and Technology Facilities Council (STFC), UK [grant number 2093954]; and the Österreichische Akademie der Wissenschaften."--Fundin

    Double Copy from Tensor Products of Metric BV{}^{\color{gray} \blacksquare}-algebras

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    Field theories with kinematic Lie algebras, such as field theories featuring colour-kinematics duality, possess an underlying algebraic structure known as BV{}^{\color{gray} \blacksquare}-algebra. If, additionally, matter fields are present, this structure is supplemented by a module for the BV{}^{\color{gray} \blacksquare}-algebra. We explain this perspective, expanding on our previous work and providing many additional mathematical details. We also show how the tensor product of two metric BV{}^{\color{gray} \blacksquare}-algebras yields the action of a new syngamy field theory, a construction which comprises the familiar double copy construction. As examples, we discuss various scalar field theories, Chern-Simons theory, self-dual Yang-Mills theory, and the pure spinor formulations of both M2-brane models and supersymmetric Yang-Mills theory. The latter leads to a new cubic pure spinor action for ten-dimensional supergravity. We also give a homotopy-algebraic perspective on colour-flavour-stripping, obtain a new restricted tensor product over a wide class of bialgebras, and we show that any field theory (even one without colour-kinematics duality) comes with a kinematic LL_\infty-algebra.Comment: v2: 97 pages, references added, typos fixed, comments welcom

    Complexity Science in Human Change

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    This reprint encompasses fourteen contributions that offer avenues towards a better understanding of complex systems in human behavior. The phenomena studied here are generally pattern formation processes that originate in social interaction and psychotherapy. Several accounts are also given of the coordination in body movements and in physiological, neuronal and linguistic processes. A common denominator of such pattern formation is that complexity and entropy of the respective systems become reduced spontaneously, which is the hallmark of self-organization. The various methodological approaches of how to model such processes are presented in some detail. Results from the various methods are systematically compared and discussed. Among these approaches are algorithms for the quantification of synchrony by cross-correlational statistics, surrogate control procedures, recurrence mapping and network models.This volume offers an informative and sophisticated resource for scholars of human change, and as well for students at advanced levels, from graduate to post-doctoral. The reprint is multidisciplinary in nature, binding together the fields of medicine, psychology, physics, and neuroscience

    Determination of the strong coupling αs from transverse energy-energy correlations in multi-jet events at √ s = 13 TeV with the ATLAS detector

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    Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física Teórica. Fecha de Lectura: 24-02-202

    Prediction & Active Control of Multi-Rotor Noise

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    Significant developments have been made in designing and implementation of Advanced Air Mobility Vehicles (AAMV). However, wider applications in urban areas require addressing several challenges, such as safety and quietness. These vehicles differ from conventional helicopter in that they operate at a relatively lower Reynolds number. More chiefly, they operate with multiples of rotors, which may pose some issues aerodynamically, as well as acoustically. The aim of this research is to first investigate the various noise sources in multi-rotor systems. High-fidelity simulations of two in-line counter-rotating propellers in hover, and in forward flight conditions are performed. Near field flow and acoustic properties were resolved using Hybrid LES-Unsteady RANS approach. Far-field sound predictions were performed using Ffowcs-Williams-Hawkings formulation. The two-propeller results in hovering are compared with that of the single propeller. This enabled us to identify the aerodynamic changes resulting from the proximity of the two propellers to each other and to understand the mechanisms causing the changes in the radiated sound. It was discovered that there is a dip in the thrust due to the relative proximity of the rotors. Owing to this, there is also some acoustic banding above the rotors mainly because they operate at the same rotational rate. We then considered the forward flight case and compared it with the corresponding hovering case. This enabled us to identify the aerodynamic changes resulting from the incoming stream. By examining the near acoustic field, the far-field spectra, the Spectral Proper Orthogonal Decomposition, and by conducting periodic averaging, we were able to identify the sources of the changes to the observed tonal and broadband noise. The convection of the oncoming flow was seen to partially explain the observed enhancement in the tonal and BBN, compared to the hovering case. It is well known that High fidelity methods are critical in predicting the full spectrum of rotor acoustics. However, these methods can be prohibitively expensive. We present here an investigation of the feasibility of reduction methods such as Proper Orthogonal Decomposition as well as Dynamic Mode decomposition for reduction of data obtained via Hybrid Large-Eddy – Unsteady Reynolds Averaged Navier Stokes approach (HLES) to be used further to obtain additional parameters. Specifically, we investigate how accurate reduced models of the high-fidelity computations can be used to predict the far-field noise. It was found that POD was capable of reconstructing accurately the parameters of interest with 15-40% of the total mode energies, whereas the DMD could only reconstruct primitive parameters such as velocity and pressure loosely. A rank truncation convergence criterion \u3e 99.8% was needed for better performance of the DMD algorithm. In the far-field spectra, DMD could only predict the tonal contents in the lower- mid frequencies whiles the POD could reproduce all frequencies of interest. Lastly, we develop an active rotor noise control technology to reduce the in-plane thickness noise associated with multi-rotor Advanced Air Mobility Vehicles (AAMV). An actuation signal is determined via the Ffowcs-Williams-Hawking (FWH) formula. Two in-line rotors are considered and we showed that the FWH-determined actuation signal can produce perfect cancellation at a point target. However, the practical need is to achieve noise reduction over an azimuthal zone, not just a single point. To achieve this zonal noise reduction, an optimization technique is developed to determine the required actuation signal produced by the on-blade distribution of embedded actuators on the two rotors. For the specific geometry considered here, this produced about 9 dB reduction in the in-plane thickness noise during forward flight of the two rotors. We further developed a technology that replaces using a point actuator on each bladed by distributed micro actuators system to achieve the same noise reduction goal with significantly reduced loading amplitudes per actuator. Overall, this research deepens the knowledge base of multi-rotor interaction. We utilize several techniques for extracting various flow and acoustic features that help understand the dynamics of such systems. Additionally, we provide a more practical approach to active rotor noise control without a performance penalty to the rotor system

    2023-2024 Boise State University Undergraduate Catalog

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    This catalog is primarily for and directed at students. However, it serves many audiences, such as high school counselors, academic advisors, and the public. In this catalog you will find an overview of Boise State University and information on admission, registration, grades, tuition and fees, financial aid, housing, student services, and other important policies and procedures. However, most of this catalog is devoted to describing the various programs and courses offered at Boise State

    Pathophysiology of Spinal Cord Injury (SCI)

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    Spinal cord injury (SCI) leads to paralysis, sensory, and autonomic nervous system dysfunctions. However, the pathophysiology of SCI is complex, and not limited to the nervous system. Indeed, several other organs and tissue are also affected by the injury, directly or not, acutely or chronically, which induces numerous health complications. Although a lot of research has been performed to repair motor and sensory functions, SCI-induced health issues are less studied, although they represent a major concern among patients. There is a gap of knowledge in pre-clinical models studying these SCI-induced health complications that limits translational applications in humans. This reprint describes several aspects of the pathophysiology of spinal cord injuries. This includes, but is not limited to, the impact of SCI on cardiovascular and respiratory functions, bladder and bowel function, autonomic dysreflexia, liver pathology, metabolic syndrome, bones and muscles loss, and cognitive functions

    Modelling of crack propagation in ductile materials

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    Crack propagation in ductile materials is a major objective of fracture mechanics with numerous applications in structural analysis and engineering mechanics. The thesis is concerned with two different methods of modelling such issues, which have been employed successfully for problems in elasticity and have drawn attention in the fracture mechanics community in the recent years. The first one utilises the configurational forces approach and considers possible extensions to elastic-plastic materials with isotropic and kinematic hardening. The analysis of calculated examples makes clear that this method is generally not an appropriate one. Mathematically, this becomes noticeable by the fact that resulting J-integral expressions are path-dependent and physically, through the knowledge that it is not an easy matter to define a crack driving force unambiguously. Hence, a second method is applied, which addresses crack propagation for ductile materials in the frameworks of phase field theories and non-conventional thermodynamics. Again, plasticity with isotropic and kinematic hardening is supposed. Simulated examples and physical considerations suggest to employ the methods and ideas of traditional continuum damage mechanics as basis for the constitutive modelling. Accordingly, a new phase field model for ductile crack propagation is proposed. The capabilities of the model are verified with reference to one-, two- and three-dimensional examples, calculated with the finite element method. The analysis of these examples reveals that the proposed model is well suited for predicting crack propagation in ductile materials, subject to complex and in particular to cyclic loading conditions
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