Search results for "loop"
showing 10 items of 608 documents
X-ray flare modeling in the single giant HR 9024
2005
We analyze a Chandra-HETGS observation of the single G-type giant HR 9024. The high flux allows us to examine spectral line and continuum diagnostics at high temporal resolution, to derive plasma parameters (thermal distribution, abundances, temperature, ...). A time-dependent 1D hydrodynamic loop model with semi-length 10$^{12}$cm ($\sim R_{\star}$), and impulsive footpoint heating triggering the flare, satisfactorily reproduces the observed evolution of temperature and emission measure, derived from the analysis of the strong continuum emission. The observed characteristics of the flare appear to be common features in very large flares in active stars (also pre-main sequence stars), possi…
PCB-Based Planar Inductive Loops for Partial Discharges Detection in Power Cables
2022
Partial discharge (PD) diagnosis tests, including detecting, locating, and identifying, are used to trace defects or faults and assess the degree of aging in order to monitor the insulation condition of medium- and high-voltage power cables. In this context, an experimental evaluation of three different printed circuit board (PCB)-based inductive sensor topologies, with spiral, non-spiral, and meander shapes, is performed. The aim is to assess their capabilities for PD detection along a transmission power cable. First, simulation and experimental characterization are carried out to determine the equivalent electrical circuit and the quality factor of the three sensors. PD activity was studi…
On Capturing Oil Rents with a National Excise Tax Revisited
2004
In this paper the scope of Bergstrom’s (1982) results is studied. Moreover, his analysis is extended assuming that extraction cost is directly related to accumulated extractions. For the case of a competitive market it is found that the optimal policy is a constant tariff if extraction is costless. However, with depletion effects, the optimal tariff must ultimately be decreasing. For the case of a monopolistic market the results depend crucially on the kind of strategies the importing country governments can play and on whether the monopolist chooses the price or extraction rate. For a price-setting monopolist it is shown that the importing countries cannot use a tariff to capture monopoly …
3 ′-5 ′ crosstalk contributes to transcriptional bursting
2019
Abstract Background Transcription in mammalian cells is a complex stochastic process involving shuttling of polymerase between genes and phase-separated liquid condensates. It occurs in bursts, which results in vastly different numbers of an mRNA species in isogenic cell populations. Several factors contributing to transcriptional bursting have been identified, usually classified as intrinsic, in other words local to single genes, or extrinsic, relating to the macroscopic state of the cell. However, some possible contributors have not been explored yet. Here, we focus on processes at the 3 ′ and 5 ′ ends of a gene that enable reinitiation of transcription upon termination. Results Using Bay…
Computation of lock-in range for classic PLL with lead-lag filter and impulse signals
2016
For a classic PLL with square waveform signals and lead-lag filter for all possible parameters lock-in range is computed and corresponding diagrams are given. peerReviewed
Hold-in, Pull-in and Lock-in Ranges for Phase-locked Loop with Tangential Characteristic of the Phase Detector
2019
In the present paper the phase-locked loop (PLL), an electric circuit widely used in telecommunications and computer architectures is considered. A new modification of the PLL with tangential phase detector characteristic and active proportionally-integrating (PI) filter is introduced. Hold-in, pull-in and lock-in ranges for given circuit are studied rigorously. It is shown that lock-in range of the new PLL model is infinite, compared to the finite lock-in range of the classical PLL. peerReviewed
Asymptotic expansions and causal representations through the loop-tree duality
2022
Large-scale particle physics experiments have provided a vast amount of high-quality data during the last decades. A leading role has been played by the Large Hadron Collider where the evaluation and analysis of its second run is currently still in progress while the third run is about to start, promising ever higher precision data of particle collisions and subsequent decays. The agreement between experimental observations and theoretical predictions using the Standard Model of Particle Physics is excellent. Indeed, this is a problem since there are currently few clues for how genuine shortcomings of the model can be overcome. New physics phenomena can appear either at higher energies, whi…
On the mathematical properties of multi-loop scattering amplitudes through the loop-tree duality
2023
El asombroso desarrollo de los experimentos de física de altas energías, como el Gran Colisionador de Hadrones del CERN, ha permitido obtener datos de gran calidad. El interés por comprender estos datos ha dado lugar a la necesidad de aumentar la precisión de las predicciones teóricas correspondientes. En esta tesis se desarrolla desde sus fundamentos matemáticos un método enfocado en cálculos de alta precisión denominado Loop-Tree Duality (dualidad lazo-árbol). Presentamos una clasificación de los diagramas de Feynman con respecto a su topología más que en el número de loops, en donde todas las clases topológicas pueden tener un número arbitrario L de loops y que se distinguen en su topolo…
From a causal representation of multiloop scattering amplitudes to quantum computing in the Loop-Tree Duality
2023
La teoría cúantica de campos con enfoque perturbativo ha logrado de manera exitosa proporcionar predicciones teóricas increíblemente precisas en física de altas energías. A pesar del desarrollo de diversas técnicas con el objetivo de incrementar la eficiencia de estos cálculos, algunos ingredientes continuan siendo un verdadero reto. Este es el caso de las amplitudes de dispersión con lazos múltiples, las cuales describen las fluctuaciones cuánticas en los procesos de dispersión a altas energías. La Dualidad Lazo-Árbol (LTD) es un método innovador, propuesto con el objetivo de afrontar estas dificultades abriendo las amplitudes de lazo a amplitudes conectadas de tipo árbol. En esta tesis pr…
Rationale and Design of the Efficacy of a Standardized Diuretic Protocol in Acute Heart Failure Study
2021
AIMS: Although acute heart failure (AHF) with volume overload is treated with loop diuretics, their dosing and type of administration are mainly based upon expert opinion. A recent position paper from the Heart Failure Association (HFA) proposed a step-wise pharmacologic diuretic strategy to increase the diuretic response and to achieve rapid decongestion. However, no study has evaluated this protocol prospectively. METHODS AND RESULTS: The Efficacy of a Standardized Diuretic Protocol in Acute Heart Failure (ENACT-HF) study is an international, multicentre, non-randomized, open-label, pragmatic study in AHF patients on chronic loop diuretic therapy, admitted to the hospital for intravenous …