Class Of Observables Research Articles

Formation of CN and CO Molecules in the Envelope of Nova V1391 Cas During the Near-maximum Phase

Moderate-resolution spectra (R ≈ 2700) of the classical nova V1391 Cas were obtained in the near-infrared wavelength range of 0.95–2.45 μm on UT 2020 August 14.41 using the Keck II telescope and the NIRES spectrograph. The spectral analysis revealed simultaneous detection of CO and CN molecular features. The CN red-system band was observed solely in absorption, while the CO first overtone bands, encompassing both 12CO and 13CO, displayed a combination of emission and absorption features at different velocities, resembling a P-Cygni profile. This specific CO profile is unprecedented in classical novae observations. Additionally, the negative velocity shifts in the absorption bands of both CN and CO were found to be consistent with each other.

Is It Possible to Establish an Economic Trend Correlating Territorial Assessment Indicators and Earth Observation? A Critical Analysis of the Pandemic Impact in an Italian Region

The paper is set within the methodological framework of the Territorial Impact Assessment (TIA) process, which is an instrument designed to facilitate sustainable and cohesive policy-making choices at the European level. The article is developed within the context of a European H2020-RICE cooperative project, which utilises the STeMA (Sustainable Territorial Economic/Environmental Management Approach) TIA methodology to investigate the potential relationship between statistical economic indicators, specifically Gross Domestic Product, and related parameters (metadata), and Earth Observation (EO) data. The objective is to provide evidence of socioeconomic trends during the Coronavirus 2019 pandemic in the Lazio Region (Italy), with a particular focus on the metropolitan area of the Rome capital city Rome. In line with the pertinent European context and the scientific literature on the subject, the paper examines the potential for combining classical and Earth observation indicators to assess macroeconomic dimensions of development, specifically in terms of gross domestic product (GDP). The results of the analysis indicate the presence of certain correlations between grey data and EO information. The STeMA-TIA approach allows for the measurement and correlation of both qualitative and quantitative statistical indicators with typological functional areas (in accordance with European Commission-EC and Committee of Ministers responsible for Spatial/Regional Planning—CEMAT guidance) at the NUTS (Nomenclature des unités territoriales statistiques) 2 and 3 levels. This facilitates the territorialisation of information, enabling the indirect comparison of data with satellite data and economic trends. A time series of data was gathered and organised for the purpose of facilitating comparison between different periods, beginning with 2019 and extending to the present day. In order to measure and monitor the evolution of the selected territorial economies (the Lazio Region), a synthetic index (or composite indicator) was developed in the economic and epidemic dimensions. This index combines single values of indicators according to a specific STeMA methodology. It is important to note that there are some critical observations to be made about the impact on GDP, due to the discrepancy between the indicators in the two fields of observation.

Study on whitecapping dissipation process for wave modelling during tropical cyclones

The atmosphere-wave interaction is an important physical process during tropical cyclones. Understanding and modelling of this process are of great significance for the technical and functional design of coastal and harbor structures. At the high wind velocities of tropical cyclones, foams and sprays that are blown away from the sea form a slip layer between the atmosphere and the sea surface. This slip layer makes the atmosphere-wave interaction exhibit different characteristics compared with that at low wind velocities. The significant effect of this layer on the atmosphere is the reduction of aero-dynamical surface roughness, which has been used to improve the expression of the drag coefficient. On this basis, the effect of the slip layer on the sea surface is further explored in this study. The whitecap coverage may reach a low limit at high wind velocities, and a modified numerical method of whitcapping dissipation for the wave spectrum model is proposed based on the classic field observations of whitecaps. According to these observations, when developing waves appear, the variation characteristics of whitecap coverage are different from those of developed waves with low wind velocities. Thus, the critical friction velocity of wave states should be defined, which can be expressed by the threshold steepness of developed waves due to the negative correlation between wave age and wave steepness. The dissipation mode is then modified to gradually reach the limit with the increase of friction velocities, which is validated during 24 tropical cyclones measured with 26 buoys. The negative Bias of the default mode generally decreases with the increase of friction velocity, even reaching −0.8 m, while the Bias of the modified mode is mostly maintained between 0.2 m and −0.2 m.

Designing observables for measurements with deep learning

Many analyses in particle and nuclear physics use simulations to infer fundamental, effective, or phenomenological parameters of the underlying physics models. When the inference is performed with unfolded cross sections, the observables are designed using physics intuition and heuristics. We propose to design targeted observables with machine learning. Unfolded, differential cross sections in a neural network output contain the most information about parameters of interest and can be well-measured by construction. The networks are trained using a custom loss function that rewards outputs that are sensitive to the parameter(s) of interest while simultaneously penalizing outputs that are different between particle-level and detector-level (to minimize detector distortions). We demonstrate this idea in simulation using two physics models for inclusive measurements in deep inelastic scattering. We find that the new approach is more sensitive than classical observables at distinguishing the two models and also has a reduced unfolding uncertainty due to the reduced detector distortions.

Parallel superposition of small-amplitude oscillatory shear flow upon steady shear flow from rotarance theory

The power of a macromolecular theory for the transport properties of a polymeric liquid increases with the number of analytical expressions for its most important material functions. In this work, we add another of these canonical function to our recent series of material function derivations for rotarance theory. By rotarance theory, we mean the explanation of the elasticity of polymeric liquids by use of (i) the diffusion equation to get the orientation distribution in Euler coordinates, and (ii) the integration in phase space using this distribution to get the target material function. In this paper, we target parallel superposition of oscillatory shear flow upon steady shear flow. We arrive at analytical expressions for both parts of the complex viscosity in parallel superposition. We find that these explain the classic experimental observations in parallel superposition: (a) the maximum in the real part of the complex viscosity, and (b) the negative values of minus its imaginary part, and (c) the independence of the steady mean shear stress from the superposed oscillation.

NLO+NLL′ accurate predictions for three-jet event shapes in hadronic Higgs decays

We present resummed predictions at next-to-leading logarithmic accuracy matched to the exact next-to-leading order results for a set of classical event-shape observables in hadronic Higgs decays, i.e., for the channels H → gg and H → bb¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ b\\overline{b} $$\\end{document}. We furthermore consider soft-drop grooming of the hadronic final states and derive corresponding NLO+NLL′ predictions for the groomed thrust observable. Differences in the QCD radiation pattern of gluon- and quark-initiated final states are imprinted in the event-shape distributions, offering separation power for the two decay channels. In particular, we show that ungroomed event shapes in H → gg decays develop a considerably harder spectrum than in H → bb¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ b\\overline{b} $$\\end{document} decays. We highlight that soft-drop grooming can substantially alter this behaviour, unless rather inclusive grooming parameters are chosen.

Benefit of classical leveling for geoid-based vertical reference frames

Classically, vertical reference frames were realized as national or continent-wide networks of geopotential differences derived from geodetic leveling, i.e., from the combination of spirit leveling and gravimetry. Those networks are affected by systematic errors in leveling, leading to tilts in the order of decimeter to meter in larger networks. Today, there opens the possibility to establish a worldwide unified vertical reference frame based on a conventional (quasi)geoid model. Such a frame would be accessible through GNSS measurements, i.e., physical heights would be derived by the method of GNSS-leveling. The question arises, whether existing geodetic leveling data are abolished completely for the realization of vertical reference frames, are used for validation purposes only, or whether existing or future geodetic leveling data can still be of use for the realization of vertical reference frames. The question is mainly driven by the high quality of leveled potential differences over short distances. In the following we investigate two approaches for the combination of geopotential numbers from GNSS-leveling and potential differences from geodetic leveling. In the first approach, both data sets are combined in a common network adjustment leading to potential values at the benchmarks of the leveling network. In the second approach, potential differences from geodetic leveling are used as observable for regional gravity field modeling. This leads to a grid of geoid heights based on classical observables like gravity anomalies and now also on leveled potential differences. Based on synthetic data and a realistic stochastic model, we show that incorporating leveled potential differences improves the quality of a continent-wide network of GNSS-heights (approach 1) by about 40% and that formal and empirical errors of a regional geoid model (approach 2) are reduced by about 20% at leveling benchmarks. While these numbers strongly depend on the chosen stochastic model, the results show the benefit of using leveled potential differences for the realization of a modern geoid-based reference frame. Independent of the specific numbers of the improvement, an additional benefit is the consistency (within the error bounds of each observation type) of leveling data with vertical coordinates from GNSS and a conventional geoid model. Even though we focus on geodetic leveling, the methods proposed are independent of the specific technique used to observe potential (or equivalently height) differences and can thus be applied also to other techniques like chronometric or hydrodynamic leveling.

Projection hypothesis in the setting for the quantum Jarzynski equality

Projective quantum measurement is a theoretically accepted process in modern quantum mechanics. However, its projection hypothesis is widely regarded as an experimentally established empirical law. In this paper, we combine a previous result regarding the realization of a Hamiltonian process of the projection hypothesis in projective quantum measurement, where the complete set of the orbital observables of the center of mass of a macroscopic quantum mechanical system is restricted to a set of mutually commuting classical observables, and a previous result regarding the work required for an event reading (i.e. the informatical process in projective quantum measurement). Then, a quantum thermodynamic scheme is proposed for experimentally testing these two mutually independent theoretical results of projective quantum measurement simultaneously.

Perturbation estimation based single-loop decoupling control strategy for DC-based DFIG to augment MPPT and FRT capabilities

This paper proposes a single-loop decoupling controller with high-gain perturbation observer (HP-FLC) for double-VSC DFIG which can be connected to DC grid to extract maximum wind power and improve fault ride-through (FRT) capability. Lumped perturbation terms are defined in the HP-FLC to include all unknown, time-varying dynamic and external perturbations, which are actively estimated by high-gain perturbation observer. Then, a more time-efficient single-loop feedback decoupling controller is designed to compensate the perturbation estimation. This control strategy combines the advantages of classical feedback controller and perturbation observer, which is separated from the accurate system model and easy to implement. Simulation results show that the proposed control strategy can achieve better wind power extraction and stronger FRT capability compared with double-loop feedback linearization controller (DL-FLC) and single-loop feedback linearization controller (SL-FLC), and the transient performance is better than that of the sliding-mode feedback controller (SMC-FLC). Finally, an experimental platform is built to confirm the practical implementation of the proposed approach.

Impact of assimilating satellite surface velocity observations in the Mercator Ocean International analysis and forecasting global 1/4° system

Representing and forecasting global ocean velocities is challenging. Velocity observations are scarce and sparse, and are rarely assimilated in a global ocean configuration. Recently, different satellite mission candidates have been proposed to provide surface velocity measurements. To assess the impact of assimilating such data, Observing System Simulation Experiments (OSSEs) have been run in the Mercator Ocean International analysis and forecasting global 1/4° system. Results show that assimilating simulated satellite surface velocities in addition to classical observations has a positive impact on the predicted currents at the surface and below to some extent. Compared to an experiment that assimilates only the classical observations, the surface velocity root-mean-squared error (RMSE) is reduced, especially in the Tropics. From a certain depth depending on the region (e.g. 200 m in the Tropics) however, slight degradations can be spotted. Temperature and salinity RMSEs are generally slightly degraded except in the Tropics where there is a small improvement at the surface and sub-surface. Sea surface height results are mixed, with some areas having reduced RMSE and some increased. The OSSEs reported here constitute a first study and aim to provide first insights on the features that improve by assimilating surface velocity data, and those which need to be worked on.

Cosmology and the classical limit of the S-matrix

We investigate the relationships between classical observables in cosmology and the classical limit of quantum scattering amplitudes. We first look at the relation between Bogoliubov transformations and the notion of classical limit. Then, we compute the cosmological redshift for a particle in a cosmological background and the emitted gravitational waveform from a quantum field theory basis and its classical limit. We observe that there is no interpretation for the geodesic redshift purely in terms of on-shell amplitudes in flat space, given that the classical limit of a scalar 2-point vanishes when considering an FRW background with two asymptotically flat in and out regions. We resolve this apparent conundrum and recover the correct observable by showing that the action of Hermitian operators differs between the in and out regions, unlike standard approaches in flat spacetime. We then show that radiation reaction corrections to the redshift enter already at order G. Furthermore, we demonstrate that the emitted waveform can be represented solely in terms of an on-shell 3-point amplitude in flat space without energy conservation, providing a closed formula for the waveform in an impulsive FRW.

Next-to-eikonal corrected double graviton dressing and gravitational wave observables at OG2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{O}\\left({G}^2\\right) $$\\end{document}

Following a recent proposal to describe inelastic eikonal scattering processes in terms of gravitationally dressed elastic eikonal amplitudes, we motivate a collinear double graviton dressing and investigate its properties. This is derived from a generalized Wilson line operator in the worldline formalism by integrating over fluctuations of the eikonal trajectories of external particles in gravitationally interacting theories. The dressing can be expressed as a product of exponential terms — a coherent piece with contributions to all odd orders in the gravitational coupling constant and a term quadratic in graviton modes, with the former providing classical gravitational wave observables. In particular, the coherent dressing involves Oκ3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{O}\\left({\\kappa}^3\\right) $$\\end{document} subleading double graviton corrections to the Weinberg soft factor. We use this dressing to derive expressions for the waveform, radiative momentum spectrum and angular momentum. In a limiting case of the waveform, we derive the nonlinear memory effect resulting from the emission of nearly soft gravitons from a scattering process.

Linear, Nonlinear, and Distributed-Parameter Observers Used for (Renewable) Energy Processes and Systems—An Overview

Full- and reduced-order observers have been used in many engineering applications, particularly for energy systems. Applications of observers to energy systems are twofold: (1) the use of observed variables of dynamic systems for the purpose of feedback control and (2) the use of observers in their own right to observe (estimate) state variables of particular energy processes and systems. In addition to the classical Luenberger-type observers, we will review some papers on functional, fractional, and disturbance observers, as well as sliding-mode observers used for energy systems. Observers have been applied to energy systems in both continuous and discrete time domains and in both deterministic and stochastic problem formulations to observe (estimate) state variables over either finite or infinite time (steady-state) intervals. This overview paper will provide a detailed overview of observers used for linear and linearized mathematical models of energy systems and review the most important and most recent papers on the use of observers for nonlinear lumped (concentrated)-parameter systems. The emphasis will be on applications of observers to renewable energy systems, such as fuel cells, batteries, solar cells, and wind turbines. In addition, we will present recent research results on the use of observers for distributed-parameter systems and comment on their actual and potential applications in energy processes and systems. Due to the large number of papers that have been published on this topic, we will concentrate our attention mostly on papers published in high-quality journals in recent years, mostly in the past decade.

The Process of Identifying Students with Special Needs in Inclusive Elementary Schools

The identification process is the first step in determining the special needs of learners. This stage is important as a basis for conducting assessments and designing individual learning programs for learners with special needs. This research uses a qualitative descriptive method. Data collection was done through classical tests, observation and interviews. The data was presented in graphical form and then analyzed descriptively. The identification results showed 2 students with special needs. The types of special needs found are specific learning difficulties including dyslexia, dysgraphia and dyscalculia.

Classical observables using exponentiated spin factors: electromagnetic scattering

In [1], the authors argued that the Newman-Janis algorithm on the space of classical solutions in general relativity and electromagnetism could be used in the space of scattering amplitudes to map an amplitude with external scalar states to an amplitude associated to the scattering of “infinite spin particles”. The minimal coupling of these particles to the gravitational or Maxwell field is equivalent to the classical coupling of the Kerr blackhole with linearized gravity or the so-called Kerr\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{\ extrm{Kerr}} $$\\end{document} charged state with the electromagnetic field. The action of the Newman-Janis mapping on scattering amplitudes was then used to compute the linear impulse at first post-Minkowskian (1PM) order, via the Kosower, Maybee, O’Connell (KMOC) formalism. In this paper, we continue with the idea of using the Newman-Janis mapping on the space of scalar QED amplitudes to compute classical observables such as the radiative gauge field and the angular impulse. We show that for tree-level amplitudes, the Newman-Janis action can be reinterpreted as a dressing of the photon propagator. This turns out to be an efficient way to compute these classical observables. Along the way, we highlight a subtlety that arises in proving the conservation of angular momentum for scalar −Kerr\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ -\\sqrt{\ extrm{Kerr}} $$\\end{document} scattering.

Rotor Flux and EEMF Observer for Interior Permanent Magnet Synchronous Machine

In recent years, the use of the Interior Permanent Magnet Synchronous Machine (IPMSM) in various applications has grown significantly due to numerous benefits. Sensors are used to achieve high efficiency and good dynamic response in IPMSM drives but due to their high cost and reduce overall size of system,sensorless control techniques are preferred. Non-sinusoidal distribution of rotor flux and slot harmonics are present in the considered IPMSM. In this article, these problems are considered as control system disturbances. With the above-mentioned problems, the classical observer structure based on (d-q) fails to estimate at low-speed ranges. This article proposes an observer structure based on a rotor flux vector in (α-β) stationary reference frame, which works using the adaptive control law to estimate speed and position, and a non-adaptive EEMF-based observer to estimate speed and position. Moreover, a comparative analysis between both observer structures at the different speed ranges is also considered in this article. The effectiveness of the observer structure is validated by simulation tests and experimental tests using the sensorless control system with a field-oriented control scheme for 3.5 kW IPMSM drive system.

Probabilistic models for studying the potential spatial distribution of three intertidal decapods in the north of Chile (Taltal, 25°S, Antofagasta region)

Abstract The northern Chilean coast is characterized by its high productivity and diversity due to the presence of the cold, nutrient-rich water of the Humboldt Current. The coasts in the area are mainly bordered by rocky shores that provide many microhabitats for invertebrates. The aim of the present study was to analyse the spatial distribution of three sympatric intertidal decapods, Leptograpsus variegatus, Cyclograpsus cinereus and Petrolisthes granulosus, using probabilistic models. The studied locality was situated on the rocky shores of Taltal Bay, in the north of Chile. The counting of individuals could reveal the presence of the reported species, and if they did or did not coexist. The results revealed that L. variegatus and C. cinereus had a uniform pattern with Binomial distribition, whereas P. granulosus showed a random occurrence with Poisson distribution. These results would not coincide with classical observations of intertidal decapods on the rocky shores of continental Chile, as those denoted a gregarious pattern, but the distributions found would rather explain potential territorial behaviour.

Logic Meets Wigner’s Friend (and their Friends)

We take a fresh look at Wigner’s Friend thought-experiment and some of its more recent variants and extensions, such as the Frauchiger-Renner (FR) Paradox. We discuss various solutions proposed in the literature, focusing on a few questions: What is the correct epistemic interpretation of the multiplicity of state assignments in these scenarios? Under which conditions can one include classical observers into the quantum state descriptions, in a way that is still compatible with traditional Quantum Mechanics? Under which conditions can one system be admitted as an additional ‘observer’ from the perspective of another background observer? When can the standard axioms of multi-agent Epistemic Logic (that allow “knowledge transfer” between agents) be applied to quantum-physical observers? In the last part of the paper, we propose a new answer to these questions, sketch a particular formal implementation of this answer, and apply it to obtain a principled solution to Wigner Friend-type paradoxes.

Is Wave Function Collapse Necessary? Explaining Quantum Nondemolition Measurement of a Spin Qubit within Linear Evolution.

The measurement problem dates back to the dawn of quantum mechanics. Here, we measure a quantum dot electron spin qubit through off-resonant coupling with a highly redundant ancilla, consisting of thousands of nuclear spins. Large redundancy allows for single-shot measurement with high fidelity ≈99.85%. Repeated measurements enable heralded initialization of the qubit and backaction-free detection of electron spin quantum jumps, attributed to burstlike fluctuations in a thermally populated phonon bath. Based on these results we argue that the measurement, linking quantum states to classical observables, can be made without any "wave function collapse" in agreement with the Quantum Darwinism concept.

A Plausible Framework Reveals Potential Similarities in the Regulation of Immunity against Some Cancers and Some Infectious Agents: Implications for Prevention and Treatment.

Different frameworks, which are currently employed to understand how immune responses are regulated, can account for different observations reported in the classical literature. I have argued that the predominant frameworks, employed over the last two/three decades to analyze the circumstances that determine whether an immune response is generated or this potential is ablated, and that determine the class of immunity an antigen induces, are inconsistent with diverse classical observations. These observations are "paradoxical" within the context of these frameworks and, consequently, tend to be ignored by most contemporary researchers. One such observation is that low and high doses of diverse types of antigen result, respectively, in cell-mediated and IgG antibody responses. I suggest these paradoxes render these frameworks implausible. An alternative framework, The Threshold Hypothesis, accounts for the paradoxical observations. Some frameworks are judged more plausible when found to be valuable in understanding findings in fields beyond their original compass. I explore here how the Threshold Hypothesis, initially based on studies with chemically well-defined and "simple antigens", most often a purified protein, can nevertheless shed light on diverse classical and more recent observations in the fields of immunity against cancer and against infectious agents, thus revealing common, immune mechanisms. Most cancers and some pathogens are best contained by cell-mediated immunity. The success of the Threshold Hypothesis has encouraged me to employ it as a basis for proposing strategies to prevent and to treat cancer and those infectious diseases caused by pathogens best contained by a cell-mediated attack.