cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Absorption features in sub-TeV gamma-ray spectra of BL Lac objects
Creators: name: Foffano, L.
name: Vittorini, V.
name: Tavani, M.
name: Menegoni, E.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The production site of gamma rays in blazars is closely related to their interaction with the photon fields surrounding the active galactic nucleus. In this paper, we discuss an indirect method that may help to unveil the presence of ambient structures in BL Lac objects through the analysis of their gamma-ray spectrum. Gamma rays, passing through structures at different distances from the black hole, interact via $γγ$ pair production with the corresponding photon fields and produce absorption features in their spectral energy distribution. An interaction with a putative broad-line region may reduce the gamma-ray flux only if its production site were very close to the central engine. However, if jet photons interact with a bath of optical-UV seed photons produced by a narrow-line region extended over the parsec scale, the consequent $γγ$ process may cause absorption features detectable at a few hundreds GeV. The detection of such absorption features is facilitated in sources with spectra reaching TeV energies, and specifically HBLs and EHBLs (extreme blazars) may represent exceptional probes to investigate this topic. We discuss recent observations of an extreme blazar named 2WHSP J073326.7+515354 (or PGC 2402248), which shows evidence of such an absorption feature in its gamma-ray spectrum and narrow emission lines in the optical spectrum, suggesting the presence of narrow-line regions in its large-scale environment. Finally, we discuss how sub-TeV absorption features in the spectra of BL Lac objects may affect their broadband modeling, and eventually represent a powerful diagnostic tool to constrain the gamma-ray production site and the jet environment.
description: Accepted for publication in ApJ
Comprehensive Electromagnetic Transient Simulation of AC/DC Grid with Multiple Converter Topologies and Hybrid Modeling Schemes
Creators: zhuozuan shen
venkata dinavahi
Publisher: name: IEEE
Year: 2017

PETS-J Open Access Paper
This paper was written by Zhuozuan Shen and Venkata Dinavahi to investigate and report on Comprehensive Electromagnetic Transient Simulation of AC/DC Grid With Multiple Converter Topologies and Hybrid Modeling Schemes
Atlas temático sobre las identidades colectivas y tribus digitales en América Latina
Creators: name: Arroyo, Alejandro Servin
Publisher: name: Zenodo
Year: 2021
Subjects: tribus digitales
identidades colectivas

description: Este proyecto busca convertirse también en el primer atlas temático sobre las diferentes formas con las que los usuarios de medios sociales en México construyen sus identidades digitales: qué les gusta, cómo se representan, qué tipo de historias consumen, con qué contenidos interactúan y con cuáles experiencias digitales se relacionan. La identidad es algo que no termina de construirse, es fluida y está permanentemente abierta a la negociación (Weber & Mitchell, 2017), de ahí la importancia de captarla de forma continua y sistematizada. Para llevar a cabo esta empresa, se cuenta con una colección de objetos digitales nativos relacionados con expresiones de identidad social en usuarios de medios sociales (Facebook, Tik Tok, Twitter e Instagram) en México, que han sido compilados ininterrumpidamente desde 2011.
Extended 1D Method for Coherent Synchrotron Radiation including Shielding
Creators: name: Sagan, David
name: Hoffstaetter, Georg
name: Mayes, Christopher
name: Sae-Ueng, Udom
Publisher: name: arXiv
Year: 2008
Subjects: subject: Accelerator Physics (physics.acc-ph)
subject: FOS: Physical sciences

description: Coherent Synchrotron Radiation can severely limit the performance of accelerators designed for high brightness and short bunch length. Examples include light sources based on ERLs or FELs, and bunch compressors for linear colliders. In order to better simulate Coherent Synchrotron Radiation, the established 1-dimensional formalism is extended to work at lower energies, at shorter bunch lengths, and for an arbitrary configuration of multiple bends. Wide vacuum chambers are simulated by means of vertical image charges. This formalism has been implemented in the general beam dynamics code "Bmad" and its results are here compared to analytical approximations, to numerical solutions of the Maxwell equations, and to the simulation code "elegant".
WEBINAR: KBase - A knowledge base for systems biology
Creators: name: Dow, Ellen
name: Wood-Charlson, Elisha
Publisher: name: Zenodo
Year: 2021
Subjects: subject: Systems Biology
subject: FAIR Research
subject: Open Source Software
subject: Metagenomics
subject: Microbiology
subject: FOS: Biological sciences
subject: http://edamontology.org/topic_2259
subject: http://edamontology.org/topic_3174

description: This record includes training materials associated with the Australian BioCommons webinar ‘KBase - A knowledge base for systems biology’. This webinar took place on 22 September 2021. Event description Developed for bench biologists and bioinformaticians, The Department of Energy Systems Biology Knowledgebase (KBase) is a free, open source, software and data science platform designed to meet the grand challenge of systems biology: predicting and designing biological function. This webinar will provide an overview of the KBase mission and user community, as well as a tour of the online platform and basic functionality. You’ll learn how KBase can support your research: Upload data, run analysis tools (Apps), share your analysis with collaborators, and publish your data and reproducible workflows. We’ll highlight a brand new feature that enables users to link environment and measurement data to sequencing data. You’ll also find out how KBase supports findable, accessible, interoperable, and reusable (FAIR) research by providing open, reproducible, shareable bioinformatics workflows. Materials are shared under a Creative Commons Attribution 4.0 International agreement unless otherwise specified and were current at the time of the event. Files and materials included in this record: Event metadata (PDF): Information about the event including, description, event URL, learning objectives, prerequisites, technical requirements etc. Index of training materials (PDF): List and description of all materials associated with this event including the name, format, location and a brief description of each file. Q&A for Australian BioCommons KBase Webinar [PDF]: Document containing answers to questions asked during the webinar and links to additional resources Introduction to KBase: Australian BioCommons Webinar [PDF]: Slides presented during the webinar Materials shared elsewhere: A recording of the webinar is available on the Australian BioCommons YouTube Channel: https://youtu.be/tJ94i9gOJfU The slides are also available as Google slides: https://tinyurl.com/KBase-webinar-slides
Multi-Rate Mixed-Solver for Real-Time Nonlinear Electromagnetic Transient Emulation of AC/DC Networks on FPGA-MPSoC Architecture
Creators: Tong Duan
Zhuoxuan Shen
Venkata Dinavahi
Publisher: name: IEEE
Year: 2019

This work proposes a novel multi-rate mixed-solver for AC/DC systems, wherein both iterative and non-iterative solvers with different time-steps are applied to the decomposed subsystems, and the linear solvers are reused within each time-step.
Nonlinear phenomena widely exist in AC/DC power systems, which should be accounted for accurately in real-time electromagnetic transient (EMT) simulation for obtaining precise results for hardware-in-the-loop applications. However, iterative solutions such as the Newton-Raphson method that can precisely obtain the results for highly nonlinear elements, are time consuming and computationally onerous. To fully utilize the time space and optimize hardware computation resources without loss of accuracy, this work proposes a novel multi-rate mixed-solver for AC/DC systems, wherein both iterative and non-iterative solvers with different time-steps are applied to the decomposed subsystems, and the linear solvers are reused within each time-step. The proposed solver and the complete real-time emulation system are implemented on FPGAMPSoC platform. The real-time results are captured by the oscilloscope and verified with PSCAD/EMTDC and SaberRD for system-level and device-level performance evaluation.
MPEC 2023-Y71 : DAILY ORBIT UPDATE (2023 December 21)
Creators: name: Minor Planet Center Staff
Publisher: name: The Minor Planet Center
Year: 2023
Subjects: subject: Small Solar System bodies
valueUri: http://astrothesaurus.org/uat/1469

description: The Minor Planet Electronic Circulars contain information on unusual minor planets, routine data on comets and natural satellites, and occasional editorial announcements.  They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Wide Area Control of Governors and Power System Stabilizers With an Adaptive Tuning of Coordination Signals
Creators: Lazaros Zacharia
Markos Asprou
and Elias Kyriakides
Publisher: name: IEEE
Year: 2019

This paper presents the formulation of Wide Area Control signals for either coordinating all the governors of the system or coordinating simultaneously both the governor and the Power System Stabilizer of each generator.
This paper presents the formulation of Wide Area Control (WAC) signals for either coordinating all the governors of the system or coordinating simultaneously both the governor and the Power System Stabilizer (PSS) of each generator. This is achieved through the development of suitable WAC signals intended for the coordination of their common input signal (rotor speed deviation) having as objective the compensation of all the local and inter-area oscillations. Furthermore, an adaptive tuning method to estimate weights for each inter-generator interaction is also presented. This is required to regulate adaptively the level of the WAC contribution to all the local controllers. The weights are computed according to the electric connectivity between the generators. For the evaluation of the proposed methods, both offline and real-time simulations are performed on the IEEE 39-bus test system. The results indicate the substantial improvement of the system's stability when the proposed governor/PSS coordination is considered. The performance of the WAC scheme is further increased when the adaptive tuning procedure is applied. Finally, the requirement of having PMUs at each generator bus is relaxed by utilizing the coherency concept.
Fermi condensates for dynamic imaging of electro-magnetic fields
Creators: name: Koponen, T. K.
name: Pasanen, J.
name: Törmä, P.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: Ultracold gases provide micrometer size atomic samples whose sensitivity to external fields may be exploited in sensor applications. Bose-Einstein condensates of atomic gases have been demonstrated to perform excellently as magnetic field sensors \cite{Wildermuth2005a} in atom chip \cite{Folman2002a,Fortagh2007a} experiments. As such, they offer a combination of resolution and sensitivity presently unattainable by other methods \cite{Wildermuth2006a}. Here we propose that condensates of Fermionic atoms can be used for non-invasive sensing of time-dependent and static magnetic and electric fields, by utilizing the tunable energy gap in the excitation spectrum as a frequency filter. Perturbations of the gas by the field create both collective excitations and quasiparticles. Excitation of quasiparticles requires the frequency of the perturbation to exceed the energy gap. Thus, by tuning the gap, the frequencies of the field may be selectively monitored from the amount of quasiparticles which is measurable for instance by RF-spectroscopy. We analyse the proposed method by calculating the density-density susceptibility, i.e. the dynamic structure factor, of the gas. We discuss the sensitivity and spatial resolution of the method which may, with advanced techniques for quasiparticle observation \cite{Schirotzek2008a}, be in the half a micron scale.
description: 10 pages, 4 figures
Identifying and Anticipating Cyberattacks That Could Cause Physical Damage to Industrial Control Systems
Creators: Matthew G. Angle
Stuart Madnick
James L. Kirtley
Jr.
Shaharyar Khan
Publisher: name: IEEE
Year: 2019

In this paper, past examples of actual damage to cyber-physical systems are shown, threats posed by software-controlled variable frequency drives (VFDs) are analyzed, and a small-scale version of an attack on ubiquitous VFD equipment is demonstrated.
Physical control systems are increasingly controlled by reconfigurable, network-enabled devices to increase flexibility and ease commissioning and maintenance. Such capability creates vulnerabilities. Devices may be remotely reprogrammed by a malicious actor to act in unintended ways, causing physical damage to mechanical equipment, infrastructure, and life and limb. In this paper, past examples of actual damage to cyber-physical systems are shown, threats posed by software-controlled variable frequency drives (VFDs) are analyzed, and a small-scale version of an attack on ubiquitous VFD equipment is demonstrated.
title: Pflanzenalkaloide in Süßholzwurzeln: Erbgutschädigung durch Matrin und Oxymatrin unwahrscheinlich: Stellungnahme Nr. 067/2023 des BfR vom 19. Dezember 2023
Creators: name: Bundesinstitut Für Risikobewertung
Publisher: name: Bundesbehörden und Einrichtungen im Geschäftsbereich des Bundesministeriums für Ernährung und Landwirtschaft (BMEL)
Year: 2023
Subjects: subject: 000

description: BfR-Stellungnahmen, vol. 2023, no. 067
Antropomedia Express: Un atlas temático sobre las identidades colectivas digitales
Creators: name: Arroyo, Alejandro Servin
Publisher: name: Zenodo
Year: 2021
Subjects: tribus digitales
identidades colectivas
antropología digital

description: La plataforma de Antropomedia Express busca convertirse en el primer atlas temático y repositorio sobre las diferentes formas con las que los usuarios de medios sociales construyen, producen y mantienen sus identidades colectivas digitales: qué les gusta, cómo se representan, qué tipo de historias consumen, con qué contenidos interactúan y con cuáles experiencias digitales se relacionan. El repositorio, a la fecha 7 de noviembre de 2021, presenta ya 162 de las 600 fichas de estos grupos, denominados, tribus digitales, y que se han compilado a partir del estudio de sociogramas. El acceso a la plataforma está disponible en este enlace https://antropomedia.express, sin embargo, actualmente es necesario contar con un nombre de usuario y contraseña para poder hacer uso de ella.
Accelerated Sparse Matrix-Based Computation of Electromagnetic Transients
Creators: A. Abusalah
O. Saad
J. Mahseredjian
U. Karaagac
and I. Kocar
Publisher: name: IEEE
Year: 2019

This paper is related to research on parallelization methods for the simulation of electromagnetic transients.
This paper is related to research on parallelization methods for the simulation of electromagnetic transients (EMTs). It presents an automatic parallelization approach based on the solution of sparse matrices resulting from the formulation of network equations. Modified-augmented-nodal analysis is used to formulate network equations. The selected sparse matrix solver is parallelized and adapted to improve performance by pivot validity testing and partial refactorization. Refactorization is needed when dealing with varying topology networks and nonlinear models. The EMT solver employs a fully iterative method for nonlinear functions. Conventional computer CPU-based parallelization is achieved and does not require any user intervention for given arbitrary network topologies. The presented approach is tested on real networks with complex models, including nonlinearities and power-electronics converters for wind generator applications.
On Einstein equations with cosmological constant in braneworld models
Creators: name: Gholami, F.
name: Darabi, F.
name: Badali, A. Haji
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this paper, we investigate the Einstein equations with cosmological constant for Randall-Sundrum (RS) and Dvali-Gabadadze-Porrati (DGP) models to determine the warp functions in the context of warp product spacetimes. In RS model, it is shown that Einstein's equation in the bulk is reduced into the brane as a vacuum equation, having vacuum solution, which is not affected by the cosmological constant in the bulk. In DGP model, it is shown that the Einstein's equation in the bulk is reduced into the brane and along the extra dimension, where both equations are affected by the cosmological constant in the bulk. We have solved these equations in DGP model, subject to vanishing cosmological constants on the brane and along extra dimension, and obtained exact solutions for the warp functions. The solutions depend on the typical values of cosmological constant in the bulk as well as the dimension of the brane. So, corresponding to the typical values, some solutions have exponential behaviours which may be set to represent warp inflation on the brane, and some other solutions have oscillating behaviours which may be set to represent warp waves or branes waves along the extra dimension.
description: 7 pages
Resource Study of Large-Scale Electric Water Heater Aggregation
Creators: Kevin Marnell
Conrad Eustis
and Robert B. Bass
Publisher: name: IEEE
Year: 2020

This resource study examines the capabilities of a 10,000 unit water heater aggregation by subjecting the aggregate to dispatch requests of various size and duration, then analyzing how the aggregate responds to and recovers from these requests.
Residential-scale distributed energy assets, like residential electric water heaters, individually present a negligible load to the power grid. When aggregated, however, these assets can impart significant effects within a balancing area; they may be dispatched en masse to provide grid services. An aggregation of water heaters may be controlled to assume generator-like functions with the ability to effectively "decrement power" through dispatch of load. This resource study examines the capabilities of a 10,000 unit water heater aggregation by subjecting the aggregate to dispatch requests of various size and duration, then analyzing how the aggregate responds to and recovers from these requests. Results show that a large-scale aggregation of electric water heaters may effectively decrement power on the scale of megawatts when the dispatch request size and duration are appropriately considered.
Robust photonic entanglement distribution via state-independent encoding onto decoherence-free subspace
Creators: name: Yamamoto, Takashi
name: Hayashi, Kodai
name: Ozdemir, Sahin Kaya
name: Koashi, Masato
name: Imoto, Nobuyuki
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Efficient and faithful implementation of quantum information tasks, e.g., quantum computing, quantum communication and quantum metrology, requires robust and state-independent decoherence-suppressing measures to protect quantum information carriers. Here we present an experimental demonstration of a robust distribution scheme in which one photon of an entangled photon pair is successfully encoded into and decoded from a decoherence-free subspace (DFS) by a state-independent scheme. We achieved a high-fidelity distribution of the entangled state over fibre communication channel, and also demonstrated that the scheme is robust against fragility of the reference frame. The scheme, thanks to its state-independence, is also applicable to multipartite case where the photon to be distributed is entangled with many other photons. Such a universal scheme opens the possibility of robust distribution of quantum information among quantum communication and computing networks.
description: 12 pages, 3 figures
A train of shocks at 3000 au scale? Exploring the clash of an expanding bubble into the NGC 1333 IRAS 4 region. SOLIS XIV
Creators: name: De Simone, Marta
name: Codella, Claudio
name: Ceccarelli, Cecilia
name: López-Sepulcre, Ana
name: Neri, Roberto
name: Rivera-Ortiz, Pedro Ruben
name: Busquet, Gemma
name: Caselli, Paola
name: Bianchi, Eleonora
name: Fontani, Francesco
name: Lefloch, Bertrand
name: Oya, Yoko
name: Pineda, Jaime E.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: There is evidence that the star formation process is linked to the intricate net of filaments in molecular clouds, which may be also due to gas compression from external triggers. We studied the southern region of the Perseus NGC 1333 molecular cloud, known to be heavily shaped by similar external triggers, to shed light on the process that perturbed the filament where the Class 0 IRAS4 protostars lie. We use new IRAM-NOEMA observations of SiO and CH3OH, both known to trace violent events as shocks, toward IRAS 4A as part of the Large Program Seeds Of Life in Space (SOLIS). We detected three parallel elongated ($>$6000 au) structures, called fingers, with narrow line profiles (~1.5 $km s^{-1}$) peaked at the cloud systemic velocity, tracing gas with high density (5-20 $10^5 cm^{-3}$) and high temperature (80-160 K). They are chemically different, with the northern finger traced by both SiO and CH3OH ([CH3OH]/[SiO]~160-300), while the other two only by SiO ([CH3OH]/[SiO]$$5000 yr, would be consistent with the observations if a substantial fraction of silicon, frozen onto the grain mantles, is released by the shocks.We suggest that the shock train is due to an expanding gas bubble, coming behind NGC 1333 from the southwest and clashing against the filament, where IRAS 4A lies. Finally, we propose a solution to the two-decades long debate on the nature and origin of the widespread narrow SiO emission observed in the south part of NGC 1333, namely that it is due to unresolved trains of shocks.
description: accepted to MNRAS, stac083
Topological Phase Transitions and Holonomies in the Dimer Model
Creators: name: Nash, Charles
name: O'Connor, Denjoe
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Lattice (hep-lat)
subject: Mathematical Physics (math-ph)
subject: Algebraic Geometry (math.AG)
subject: Combinatorics (math.CO)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We demonstrate that the classical dimer model defined on a toroidal hexagonal lattice acquires holonomy phases in the thermodynamic limit. When all activities are equal the lattice sizes must be considered mod 6 in which case the finite size corrections to the bulk partition function correspond to a massless Dirac Fermion in the presence of a flat connection with nontrivial holonomy. For general bond activities we find that the phase transition in this model is a topological one, where the torus degenerates and its modular parameter becomes real at the critical temperature. We argue that these features are generic to bipartite dimer models and we present a more general lattice whose continuum partition function is that of a massive Dirac Fermion.
description: 7 pages, 4 figures. Minor corrections with additional figures
Problem of the 8th Experimental Physics Olympiad, Skopje, 8 May 2021 Determination of Planck constant by LED
Creators: name: Mishonov, T. M.
name: Petkov, A. P.
name: Andreoni, M.
name: Petkov, E. G.
name: Varonov, A. M.
name: Dimitrova, I. M.
name: Velkoska, L.
name: Popeski-Dimovski, R.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Physics Education (physics.ed-ph)
subject: FOS: Physical sciences

description: This is the problem of the 8$^\mathrm{th}$ International Experimental Physics Olympiad (EPO). The task of the EPO8 is to determine Plank constant $\hbar=h/2π$ using the given set-up with LED. If you have an idea how to do it, do it and send us the result; skip the reading of the detailed step by step instructions with increasing difficulties. We expect the participants to follow the suggested items -- they are instructive for physics education in general.Only the reading of historical remarks given in the first section can be omitted during the Olympiad without loss of generality. Participants should try solving as much tasks as they can without paying attention to the age categories: give your best.
description: 27 pages (10 main text), 11 figures, 3 tables, 18 references, 1 appendix of scanned solution (16 pages); latex source files in Bulgarian and Macedonian languages included as auxiliary files. arXiv admin note: text overlap with arXiv:1912.07368
Etiology and epidemiology of bacterial blight of red raspberry in British Columbia
Creators: name: Sinnott, Nancy Marie
Publisher: name: University of British Columbia
Year: 2010

description: Pseudomonas syringae van Hall was recovered from 31 of 32 samples of red raspberry tissue showing typical symptoms of bacterial blight. Of the 99 isolates recovered, 85 were physiologically-typical, P. syringae isolates, three did not produce the fluorescent pigment, six did not utilize lactate and five did not produce toxin as determined by the Geotrichum candidum bioassay. When a suspension of 10⁷ CFU/ml was sprayed on the leaves of 6-week-old raspberry plants, 42 of 48 isolates caused necrosis within 4 days. No other bacterium recovered from the diseased raspberry tissue was pathogenic to raspberry in greenhouse tests. P. syringae isolates remained viable and retained their toxin-producing ability when stored for one year on nutrient glycerol agar at 5°C. Identical isolates stored on nutrient agar at 5°C or in sterile distilled water at room temperature either did not survive or lost their toxin-producing ability. There seemed to be a relationship between toxin-producing ability and an isolate's virulence as about 50% of toxin-producing isolates were rated pathogenic and 35% weakly pathogenic while none of the non-toxin-producing isolates were rated pathogenic and 60% were rated weakly pathogenic. A scheme was devised for rapid identification of P. syringae from raspberry tissue. An isolate was determined to be P. syringae if it produced a distinctive raised mucoid colony on nutrient sucrose agar, produced a fluorescent pigment, was oxidase negative and reacted in drop agglutination tests with an antiserum prepared against syringae. These tests could be done within three days. This scheme was used to study the overwintering site of P. syringae on raspberry. P. syringae was found to naturally populate 25-75% of raspberry buds during the winter months. Populations of 10⁴ CFU/six bud sample were most common in the buds that contained P. syringae. During the spring and summer months, P. syringae survived as an epiphyte on raspberry leaves both in the field and in the greenhouse trials. P. syringae was also shown to cause brownish-red spots surrounded by yellow halos on the leaves of raspberry during the summer months. About 90% of the P. syringae isolates from raspberry were ice nucleation active. Raspberry plants that had been sprayed with a suspension of 10⁷ CFU/ml and then held at -2°C for 4 hours developed symptoms similar to those of bacterial blight within 12 hours of the freeze treatment. In preliminary tests, raspberry cultivars showed varying degrees of resistance to P. syringae infection. Raspberry cultivar Chilcotin showed greatest resistance and cultivar Mailing Leo showed greatest susceptibility to Pseudomonas syringae infection. Three different species of bacteria were found in the normal microflora of the raspberry that were antagonistic to P. syringae in vitro.
Numerical simulation of excitation and propagation of helioseismic MHD waves: Effects of inclined magnetic field
Creators: name: Parchevsky, K. V.
name: Kosovichev, A. G.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Investigation of propagation, conversion, and scattering of MHD waves in the Sun is very important for understanding the mechanisms of observed oscillations and waves in sunspots and active regions. We have developed 3D linear MHD numerical model to investigate influence of the magnetic field on excitation and properties of the MHD waves. The results show that the magnetic field can substantially change the properties of the surface gravity waves (f-mode), but their influence on the acoustic-type waves (p-modes) is rather moderate. Comparison our simulations with the time-distance helioseismology results from SOHO/MDI shows that the travel time variations caused by the inclined magnetic field do not exceed 25% of the observed amplitude even for strong fields of 1400-1900 G. This can be an indication that other effects (e.g. background flows and non-uniform distribution of magnetic field) can contribute to the observed travel time variations. The travel time variations caused by the wave interaction with magnetic field are in phase with the observations for strong fields of 1400-1900 G if Doppler velocities are taken at the height of 300 km above the photosphere where plasma parameter beta<<1. The simulations show that the travel times only weakly depend on the height of velocity observation. For the photospheric level the travel times are systematically smaller on approximately 0.12 min then for the hight of 300 km above the photosphere for all studied ranges of the magnetic field strength and inclination angles. The numerical MHD wave modeling and new data from the HMI instrument of the Solar Dynamics Observatory will substantially advance our knowledge of the wave interaction with strong magnetic fields on the Sun and improve the local helioseismology diagnostics.
description: 24 pages, 10 figures, submitted to ApJ
title: Front Matter, Table of Contents, Foreword, Conference Organization, External Reviewers, Sponsors
Creators: name: Aronov, Boris
name: Katz, Matthew J.
Publisher: name: Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Year: 2017
Subjects: subject: Front Matter
subject: Table of Contents
subject: Foreword
subject: Conference Organization
subject: External Reviewers
subject: Sponsors

description: Front Matter, Table of Contents, Foreword, Conference Organization, External Reviewers, Sponsors
description: LIPIcs, Vol. 77, 33rd International Symposium on Computational Geometry (SoCG 2017), pages 0:i-0:xviii
Ti I lines at 2.2 $μ$m as probes of the cool parts of sunspots
Creators: name: Smitha, H. N.
name: Durán, J. S. Castellanos
name: Solanki, S. K.
name: Tiwari, S. K.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The sunspot umbra harbors the coolest plasma on the solar surface due to the presence of strong magnetic fields. The routinely used atomic lines to observe the photosphere have weak signals in the umbra and are often swamped by molecular lines. This makes it harder to infer the properties of the umbra, especially in the darkest regions. The lines of the Ti I multiplet at 2.2 $μ$m are formed mainly at temperatures $\le\!4500$ K and are not known to be affected by molecular blends in sunspots. Since the first systematic observations in the 1990's, these lines have been seldom observed due to the instrumental challenges involved at these longer wavelengths. We revisit these lines and investigate their formation in different solar features. We synthesize the Ti I multiplet using a snapshot from 3D MHD simulation of a sunspot and explore the properties of two of its lines in comparison with two commonly used iron lines at 630.25 nm and $1.5648\,μ$m. We find that the Ti I lines have stronger signals than the Fe I lines in both intensity and polarization in the sunspot umbra and in penumbral spines. They have little to no signal in the penumbral filaments and the quiet Sun, at $μ=1$. Their strong and well-split profiles in the dark umbra are less affected by stray light. Consequently, inside the sunspot it is easier to invert these lines and to infer the atmospheric properties, compared to the iron lines. The Cryo-NIRSP instrument at the DKIST will provide the first ever high resolution observations in this wavelength range. In this preparatory study, we demonstrate the unique temperature and magnetic sensitivities of the Ti multiplet, by probing the Sun's coolest regions which are not favourable for the formation of other commonly used spectral lines. We thus expect such observations to advance our understanding of sunspot properties.
description: Accepted for publication in A&A
Study of Wind and PV Frequency Control in U.S. Power Grids EI and TI Case Studies
Creators: Yong Liu
Shutang You
Yilu Liu
Publisher: name: IEEE
Year: 2017

PETS-J Open Access Paper
This paper was written by Zhiyin Zhou and Venkata Dinavahi to investigate and report on the Study of Wind and PV Frequency Control in U.S. Power Grids EI and TI Case Studies
Structural identification of antibacterial components isolated from Cassia fistula
Creators: name: Sandip Kale
name: Dandge, Padma B.
Publisher: name: figshare
Year: 2021
Subjects: subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences

description: The present study was designed for isolation, purification, and chemical characterization of components from Cassia fistula responsible for antibacterial activity. The crude extract of leaves of Cassia fistula prepared using methanol as a solvent and phytochemical evaluation was done. An invitro antibacterial assay was conducted to evaluate the inhibitory activity of methanol extract against E. coli and B. cereus. The methanol extract was subjected to column chromatography with different mobile phases followed by TLC. HPLC of fractions showing maximum inhibitory activity against E. coli and B. cereus was performed. The chemical characterization of isolated compounds was achieved using FTIR and 1H NMR spectroscopy. Screening of antibacterial activity of methanol extract showed marked activity against both gram-positive and gram-negative bacteria. FTIR and NMR analysis data show the presence of various functional groups that correspond to potential bioactive compounds from phenolics (Rhein, Catechin), triterpenes (Hopane), and Flavonoids (Amentoflavone). This plant formulation may thereby provide an alternative solution to the current problem associated with the use of antibiotics.
NMR of $^{31}$P Nuclear Spin Singlet States in Organic Diphosphates
Creators: name: DeVience, Stephen J.
name: Walsworth, Ronald L.
name: Rosen, Matthew S.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: Medical Physics (physics.med-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: $^{31}$P NMR and MRI are commonly used to study organophosphates that are central to cellular energy metabolism. In some molecules of interest, such as adenosine diphosphate (ADP) and nicotinamide adenine dinucleotide (NAD), pairs of coupled $^{31}$P nuclei in the diphosphate moiety should enable the creation of nuclear spin singlet states, which may be long-lived and can be selectively detected via quantum filters. Here, we show that $^{31}$P singlet states can be created on ADP and NAD, but their lifetimes are shorter than T$_{1}$ and are strongly sensitive to pH. Nevertheless, the singlet states were used with a quantum filter to successfully isolate the $^{31}$P NMR spectra of those molecules from the adenosine triphosphate (ATP) background signal.
description: 11 pages, 3 figures
title: Electrochemical generation of metal structures using surface based molecular self-assemblies as templates
Creators: name: Yao, Zhen
Publisher: name: University of St Andrews
Year: 2020

description: Exploring electrochemical processes controlled by surface-based molecular assemblies, this thesis studies a coordination-controlled electrodeposition (CCED) scheme, which relies on chemical functionality, i.e., metal coordination, provided by the tail group of a self-assembled monolayer (SAM). Based on the electrochemical reduction of coordinated ions, the scheme is extended by introducing metal ions into the bulk electrolyte. Using a SAM of 3-(4-pyridine-4-yl-phenyl)-propane-1-thiol (BP3N) on Au(111) electrode, the co-deposition of coordinating Pd and non-coordinating Cu has been investigated. Following Pd²⁺-pyridine complexation, the electrochemical deposition was performed in an acidic Cu²⁺-containing electrolyte. Both cyclic voltammetry (CV) and chronoamperometry revealed the promoting effect of coordinated Pd²⁺ on bulk Cu deposition. The process involves three phases, (i) the Pd cluster formation, (ii) the intermix of Pd and Cu, and (iii) the deposition of bulk Cu. Depending on conditions, deposits with morphologies ranging from isolated CuPd nanoparticles to ultrathin metal films were generated and characterised with scanning tunnelling microscopy (STM). The Pd-Cu core-shell nature of these nanoparticles was confirmed by transmission electron microscopy (TEM). To understand the metal nucleation mechanism, density functional theory (DFT) calculations were carried out to clarify the initial stage of Pd aggregation. Furthermore, inspired by the calculation results, the effect of metal-SAM interaction in metal nucleation was illustrated by the reduced particle size for CCED on binary SAMs with protruding phenyl groups. The exploration of the CCED scheme towards nanostructure generation was investigated using either patterns of CuPd nanoparticles fabricated by selective particle removal based on scanning probe lithography (STM or atomic force microscopy) or patterned SAMs produced by electron beam lithography. Metal films with thickness below 3 nm and metal structures with lateral features down to sub-10 nm were fabricated. Additionally, with SAMs serving to control the adhesion, a cyclic scheme consisting of electrodeposition on a patterned substrate and lift-off was investigated, offering the prospect of replicative nanostructure fabrication.
Generalized gauge-invariant formulations of the strong-field approximation
Creators: name: Vanne, Yulian V.
name: Saenz, Alejandro
Publisher: name: arXiv
Year: 2008
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: The gauge problem in the so-called strong-field approximation (SFA) describing atomic or molecular systems exposed to intense laser fields is investigated. Introducing a generalized gauge and partitioning of the Hamiltonian it is demonstrated that the S-matrix expansion obtained in the SFA depends on both gauge and partitioning in such a way that two gauges always yield the same S-matrix expansion, if the partitioning is properly chosen.
description: 11 pages
Harnessing Flexible Transmission: Corrective Transmission Switching for ISO NE
Creators: Joshua Lyon
Slava Maslennikov Mostafa
Sahraei Ardakani
Tongxin Zheng
Eugene Litvinov
Xingpeng Li
Pranavamoorthy Balasubramanian
Kory Hedman
Publisher: name: IEEE
Year: 2016

PES Open Access Paper
Hydrodynamic attraction of swimming microorganisms by surfaces
Creators: name: Berke, Allison P.
name: Turner, Linda
name: Berg, Howard C.
name: Lauga, Eric
Publisher: name: arXiv
Year: 2008
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Biological Physics (physics.bio-ph)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Cells swimming in confined environments are attracted by surfaces. We measure the steady-state distribution of smooth-swimming bacteria (Escherichia coli) between two glass plates. In agreement with earlier studies, we find a strong increase of the cell concentration at the boundaries. We demonstrate theoretically that hydrodynamic interactions of the swimming cells with solid surfaces lead to their re-orientation in the direction parallel to the surfaces, as well as their attraction by the closest wall. A model is derived for the steady-state distribution of swimming cells, which compares favorably with our measurements. We exploit our data to estimate the flagellar propulsive force in swimming E. coli.
Data for Tropicalization unlocks novel trophic pathways and enhances secondary productivity in temperate reefs
Creators: name: Pessarrodona, Albert
name: Vergés, Adriana
name: Bosch, Néstor E.
name: Bell, Sahira Y.
name: Smith, Shannen M.
name: Sgarlatta, Maria Paula
name: Wernberg, Thomas
Publisher: name: figshare
Year: 2021
Subjects: subject: Ecology
subject: FOS: Biological sciences

description: This files contain the data and scripts for Pessarrodona et al. 2021, Tropicalization unlocks novel trophic pathways and enhances secondary productivity in temperate reefs, Functional Ecology
Circuit Complexity in $U(1)$ Gauge Theory
Creators: name: Moghimnejad, Amir
name: Parvizi, Shahrokh
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study circuit complexity for a free vector field of a $U(1)$ gauge theory in Coulomb gauge, and Gaussian states. We introduce a quantum circuit model with Gaussian states, including reference and target states. Using the Nielsen's geometric approach, the complexity then can be found as the shortest geodesic in the space of states. This geodesic is based on the notion of geodesic distance on the Lie group of Bogoliubov transformations equipped with a right-invariant metric. We use the framework of the covariance matrix to compute circuit complexity between Gaussian states. We apply this framework to the free vector field in general dimensions where we compute the circuit complexity of the ground state of the Hamiltonian.
description: 11 pages, submitted to MPLA
Incidence Rate of GRB-host-DLAs at High Redshift
Creators: name: Nagamine, Kentaro
name: Zhang, Bing
name: Hernquist, Lars
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We study the incidence rate of damped Ly-a systems associated with the host galaxies of gamma-ray bursts (GRB-host-DLAs) as functions of neutral hydrogen column density (N_HI) and projected star formation rate (SFR) using cosmological SPH simulations. Assuming that the occurrence of GRBs is correlated with the local SFR, we find that the median N_HI of GRB-host-DLAs progressively shifts to lower N_HI values with increasing redshift, and the incidence rate of GRB-host-DLAs with log N_HI > 21.0 decreases rapidly at z>=6. Our results suggest that the likelihood of observing the signature of IGM attenuation in GRB afterglows increases towards higher redshift, because it will not be blocked by the red damping wing of DLAs in the GRB host galaxies. This enhances the prospects of using high-redshift GRBs to probe the reionization history of the Universe. The overall incidence rate of GRB-host-DLAs decreases monotonically with increasing redshift, whereas that of QSO-DLAs increases up to z=6. A measurement of the difference between the two incidence rates would enable an estimation of the value of η_grb, which is the mass fraction of stars that become GRBs for a given amount of star formation. Our predictions can be tested by upcoming high-z GRB missions, including JANUS (Joint Astrophysics Nascent Universe Scout) and SVOM (Space multi-band Variable Object Monitor).
description: 5 pages, 3 figures, ApJL, in press
Applications of Real-Time Simulation Technologies in Power and Energy Systems
Creators: Xavier Guillard
M Omar Faruque
Alexandre Teninge
Ali Hasan Hariri
Luigi Vanfretti
Mario Paolone
Venkata Dinavahi
Pinaki Mitra
Georg Lauss
Christian Dufour
Paul Forsyth
Anurag Srivastava
Kai Strunz
Thomas Strasser
Ali Davoudi
Publisher: name: IEEE
Year: 2015

PES Open Access Paper
Planning for conservacy areas : recreation in estuarine bird habitat
Creators: name: Schade, Frieda Marion
Publisher: name: University of British Columbia
Year: 2010

description: This thesis analyses a problem that is common in planning for conservacy areas — the problem of the meeting dual and contradictory objectives of preserving natural areas that must also be used for recreation. Where one objective excludes the other, a compromise must be reached. Previous experience in North America has shown that it is not easy to reconcile the two functions. A case study approach is used in the thesis. The study area, Boundary Bay, is an important waterfowl and shore-bird habitat. The Bay also has the potential to serve many recreational needs close to an urban area, Greater Vancouver. The role of Boundary Bay, including Mud and Semiahmoo Bays, and their shorelands in the ecology of wildlife species is analysed using census and food chain data. Information collected for an inventory of regional recreation suggests which recreation needs might be satisfied at Boundary Bay. Guidelines are developed for integration of human activity and wildlife habitat, based on anticipated recreational use of the Bay. Data from four public meetings in Surrey points to the existence of some concern on the part of Bay area residents about the implications of conservacy use of the Bay. Suggestions for further investigation or resolution of these conflicts are made. The issues involved in planning Boundary Bay are complex ones because of the number of interests involved. There is no "right" way of proceeding. Four scenarios are developed to illustrate alternative means of applying resource management guidelines and measures for resolution of conflicts to the study area. Each alternative requires a different level and type of management with different implications for long term reconciliation of use with preservation.
Transition criteria and phase space structures in a three degree of freedom system with dissipation
Creators: name: Zhong, Jun
name: Ross, Shane D.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: Dynamical Systems (math.DS)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: Escape from a potential well through an index-1 saddle can be widely found in some important physical systems. Knowing the criteria and phase space geometry that govern escape events plays an important role in making use of such phenomenon, particularly when realistic frictional or dissipative forces are present. We aim to extend the study the escape dynamics around the saddle from two degrees of freedom to three degrees of freedom, presenting both a methodology and phase space structures. Both the ideal conservative system and a perturbed, dissipative system are considered. We define the five-dimensional transition region, $\mathcal{T}_h$, as the set of initial conditions of a given initial energy $h$ for which the trajectories will escape from one side of the saddle to another. Invariant manifold arguments demonstrate that in the six-dimensional phase space, the boundary of the transition region, $\partial \mathcal{T}_h$, is topologically a four-dimensional hyper-cylinder in the conservative system, and a four-dimensional hyper-sphere in the dissipative system. The transition region $\mathcal{T}_h$ can be constructed by a solid three-dimensional ellipsoid (solid three-dimensional cylinder) in the three-dimensional configuration space, where at each point, there is a cone of velocity -- the velocity directions leading to transition are given by cones, with velocity magnitude given by the initial energy and the direction by two spherical angles with given limits. To illustrate our analysis, we consider an example system which has two potential minima connected by an index 1 saddle.
description: 26 pages, 6 figures