cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Performance Evaluation of Different Low-Cost DIY Air Cleaner Configurations
Creators: name: Myers, Nirmala T.
name: Dillon, Kevin P.
name: Han, Taewon T.
name: Mainelis, Gediminas
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Biophysics
subject: Space Science
subject: Chemical Sciences not elsewhere classified
subject: Ecology
subject: FOS: Biological sciences
subject: Biological Sciences not elsewhere classified
subject: Information Systems not elsewhere classified
subject: Science Policy

description: Do-it-yourself (DIY) air cleaners have been proposed as an affordable alternative to expensive portable HEPA air cleaners; however, their performance data are still limited. This study evaluated the performance of single- and multi-filter DIY air cleaner configurations with different filter thickness (1, 2, and 4 inches) and MERV ratings (8, 11, and 13). The filters were selected based on their availability to the public, with the resulting cost of less than 50 and 100 USD for single- and multi-filter configurations, respectively. DIY air cleaners were challenged with polydisperse NaCl particles, and their clean air delivery rate (CADR) was determined for ultrafine (< 100 nm) and 300 nm particle number concentration and PM2.5 mass concentration. Twelve single-filter configurations with filters from three companies, a 2-filter configuration, and a Corsi-Rosenthal (C-R) box with four 2-inch filters were tested. The CADR ranged from 84 to 635 cfm, depending on the particle metric and filter configuration. Among the single-filter configurations, the 4-inch filter performed the best. The multi-filter models, especially the C-R box, demonstrated the highest CADR: comparable to and exceeding the CADR of portable HEPA air cleaners. In addition, the C-R box also provided the highest CADR per power input while resulting in the lowest noise level and fan motor temperature. In addition to performance, the cost of operating and maintaining DIY air cleaners is also discussed. Overall, this study shows that DIY air cleaners are an affordable and effective means to reduce particulate air pollutants, thus improving indoor air quality.
Derivation of Higher Dimensional Periodic Recurrence Equations by Nested Structure of Complex Numbers
Creators: name: Yumibayashi, Tsukasa
Publisher: name: arXiv
Year: 2016
Subjects: subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: In this paper, we give a procedure for derivation of higher dimensional periodic recurrence equations(PREs) by nested structure of complex numbers.
description: 13 pages, 1 figure
The critical groups of the Peisert graphs $P^*(q)$
Creators: name: Sin, Peter
Publisher: name: arXiv
Year: 2016
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 05C50

description: The critical group of a finite graph is an abelian group defined by the Smith normal form of the Laplacian. We determine the the critical groups of the Peisert graphs, a certain family of strongly regular graphs similar to, but different from, the Paley graphs. It is further shown thatthe adjacency matrices of the two graphs defined over a field of order $p^2$ with $p\equiv 3\pmod 4$ are similar over the $\ell$-local integers for every prime $\ell$. Consequently, each such pair of graphs provides an example where all the corresponding generalized adjacency matrices are both cospectral and equivalent in the sense of Smith normal form.
description: 16 pages
A Machine Learning based Approach to Solve the Aerosol Dynamics Coagulation Model
Creators: name: Okonkwo, Onochie
name: Patel, Rahul
name: Gudi, Ravindra
name: Biswas, Pratim
Publisher: name: Taylor & Francis
Year: 2023
Subjects: Biotechnology
Biological Sciences not elsewhere classified
Information Systems not elsewhere classified
Computational Biology

description: Solving aerosol dynamic models accurately to obtain the size distribution function is often computationally expensive. Conventional artificial neural network (ANN) models offer an alternative procedure to solve the aerosol dynamic equations. However, conventional ANN models can result in violation of aerosol mass conservation. To further enhance accuracy and reduce computational time, a hybrid ANN approach to solve the aerosol coagulation equation is developed, validated, and demonstrated. The methodology and assumptions for the development of the hybrid ANN model which provides an analytical closed form solution for aerosol coagulation is described. The ANN model is trained and validated using a dataset from an accurate sectional model. Following this, the hybrid ANN aerosol model is used to describe the evolution of aerosol in a furnace aerosol reactor. The hybrid ANN model results are compared to the accurate sectional and moment coagulation models. The hybrid ANN coagulation model prediction was found to accurately describe the evolution of the size distribution at a computational cost which is slightly more than the moment model but orders of magnitude less than the sectional model.
An operational measure for squeezing
Creators: name: Idel, Martin
name: Lercher, Daniel
name: Wolf, Michael M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mathematical Physics (math-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We propose and analyse a mathematical measure for the amount of squeezing contained in a continuous variable quantum state. We show that the proposed measure operationally quantifies the minimal amount of squeezing needed to prepare a given quantum state and that it can be regarded as a squeezing analogue of the "entanglement of formation". We prove that the measure is convex and superadditive and we provide analytic bounds as well as a numerical convex optimisation algorithm for its computation. By example, we then show that the amount of squeezing needed for the preparation of certain multi-mode quantum states can be significantly lower than naive approaches suggest.
description: 51+7 pages, 2 figures, comments always welcome
Designing a Broadband Pump for High-Quality Micro-Lasers via Modified Net Radiation Method
Creators: name: Nechayev, Sergey
name: Reusswig, Philip D.
name: Baldo, Marc A.
name: Rotschild, Carmel
Publisher: name: arXiv
Year: 2016
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: High-quality micro-lasers are key ingredients in non-linear optics, communication, sensing and low-threshold solar-pumped lasers. However, such micro-lasers exhibit negligible absorption of free-space broadband pump light. Recently, this limitation was lifted by cascade energy transfer, in which the absorption and quality factor are modulated with wavelength, enabling non-resonant pumping of high-quality micro-lasers and solar-pumped laser to operate at record low solar concentration. Here, we present a generic theoretical framework for modeling the absorption, emission and energy transfer of incoherent radiation between cascade sensitizer and laser gain media. Our model is based on linear equations of the modified net radiation method and is therefore robust, fast converging and has low complexity. We apply this formalism to compute the optimal parameters of low-threshold solar-pumped lasers. It is revealed that the interplay between the absorption and self-absorption of such lasers defines the optimal pump absorption below the maximal value, which is in contrast to conventional lasers for which full pump absorption is desired. Numerical results are compared to experimental data on a sensitized Nd:YAG cavity, and quantitative agreement with theoretical models is found. Our work modularizes the gain and sensitizing components and paves the way for the optimal design of broadband-pumped high-quality micro-lasers and efficient solar-pumped lasers.
description: Manuscript with supplementary
Supplementary document for Measurements of slow tissue dynamics with short-separation speckle contrast optical spectroscopy - 6563591.pdf
Creators: name: Liu, Bingxue
name: Shah, Shashwat
name: Küreli, Gülce
name: Devor, Anna
name: Boas, David
name: Cheng, Xiaojun
Publisher: name: Optica Publishing Group
Year: 2023
Subjects: Uncategorized

description: Supplementary Information
An Optical and Near-Infrared Study of the Type Ia/IIn Supernova PS15si
Creators: name: Kilpatrick, Charles D.
name: Andrews, Jennifer E.
name: Smith, Nathan
name: Milne, Peter
name: Rieke, George H.
name: Zheng, WeiKang
name: Filippenko, Alexei V.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We present optical/near-infrared spectroscopy and photometry of the supernova (SN) PS15si. This object was originally identified as a Type IIn SN, but here we argue that it should be reclassified as a Type Ia SN with narrow hydrogen lines originating from interaction with circumstellar matter (CSM; i.e., SN Ia/IIn or SN Ia-CSM). Based on deep nondetections 27 days before discovery, we infer that this SN was discovered around or slightly before optical maximum, and we estimate the approximate time that it reached R-band maximum based on comparison with other SNe Ia/IIn. In terms of spectral morphology, we find that PS15si can be matched to a range of SN Ia spectral types, although SN 1991T-like SNe Ia provides the most self-consistent match. While this observation agrees with analysis of most other SNe Ia/IIn, we find that the implied CSM luminosity is too low to account for the overall luminosity of the SN at a time when the CSM should outshine the underlying SN by a few magnitudes. We infer that the similarity between PS15si and the hot, overluminous, high-ionisation spectrum of SN 1991T is a consequence of a spectrum that originates in ejecta layers that are heated by ultraviolet/X-ray radiation from CSM interaction. In addition, PS15si may have rebrightened over a short timescale in the B and V bands around 85 days after discovery, perhaps indicating that the SN ejecta are interacting with a local enhancement in CSM produced by clumps or a shell at large radii.
description: submitted to MNRAS
Constraints on atmospheric charmed-meson production from IceCube
Creators: name: Palczewski, Tomasz
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: At very-high energies (100 TeV - 1 PeV), the small value of Bjorken-x ($\le10^{-3}-10^{-7}$) at which the parton distribution functions are evaluated makes the calculation of charm quark production very difficult. The charm quark has mass ($\sim$1.5$\pm$0.2 GeV) significantly above the $Λ$$_{QCD}$ scale ($\sim$200 MeV), and therefore its production is perturbatively calculable. However, the uncertainty in the data and the calculations cannot exclude some smaller non-perturbative contribution. To evaluate the prompt neutrino flux, one needs to know the charm production cross-section in pN -> c$\bar{c}$ X, and hadronization of charm particles. This contribution briefly discusses computation of prompt neutrino flux and presents the strongest limit on prompt neutrino flux from IceCube.
description: Meson 2016. The conference proceedings will be published as a special issue of EPJ Web of Conferences
Impact of embedding on predictability of failure-recovery dynamics in networks
Creators: name: Böttcher, Lucas
name: Lukovic, Mirko
name: Nagler, Jan
name: Havlin, Shlomo
name: Herrmann, Hans J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: Failure, damage spread and recovery crucially underlie many spatially embedded networked systems ranging from transportation structures to the human body. Here we study the interplay between spontaneous damage, induced failure and recovery in both embedded and non-embedded networks. In our model the network's components follow three realistic processes that capture these features: (i) spontaneous failure of a component independent of the neighborhood (internal failure), (ii) failure induced by failed neighboring nodes (external failure) and (iii) spontaneous recovery of a component.We identify a metastable domain in the global network phase diagram spanned by the model's control parameters where dramatic hysteresis effects and random switching between two coexisting states are observed. The loss of predictability due to these effects depend on the characteristic link length of the embedded system. For the Euclidean lattice in particular, hysteresis and switching only occur in an extremely narrow region of the parameter space compared to random networks. We develop a unifying theory which links the dynamics of our model to contact processes. Our unifying framework may help to better understand predictability and controllability in spatially embedded and random networks where spontaneous recovery of components can mitigate spontaneous failure and damage spread in the global network.
description: 22 pages, 20 figures
School Improvement Program Implementation Practices in Secondary Schools of South West Oromia Region: Teaching Learning Domain in Focus
Creators: name: Tafesse, Mebratu
Publisher: name: African Journal of Leadership and Development
Year: 2022

description: The study aimed at investigating the teaching and learning domain implementation practices within the framework of f School Improvement Program. A concurrent mixed research design was used to collect quantitative and qualitative data. Respondents were randomly selected and included in the study. Questionnaires and document analyses were used to gather data for the study. A total of 410 questionnaires were distributed and 374 (91 %) were properly filled and returned. Descriptive and inferential statistics were used for analyzing the data. It was found that professional development is poorly practiced; student-centered active learning methodologies are not well practiced while learning and evaluation activities are moderately practiced in support of student learning. Thus, the teaching and learning domain was not effectively implemented to improve student learning. It is recommended that the zone education offices should initiate need-based capacity development program and periodically provide on-the-job training for teachers and school leaders to develop their professional knowledge and skill.
description: African Journal of Leadership and Development, Vol. 7 No. 1 (2022): Strategic Leadership
Preliminary design of the INPE's Solar Vector Magnetograph
Creators: name: Vieira, L. E. A.
name: de Gonzalez, A. L. Clúa
name: Lago, A. Dal
name: Wrasse, C.
name: Echer, E.
name: Guarnieri, F. L.
name: Cardoso, F. Reis
name: Guerrero, G.
name: Costa, J. Rezende
name: Palacios, J.
name: Balmaceda, L.
name: Alves, L. Ribeiro
name: da Silva, L.
name: Costa, L. L.
name: Sampaio, M.
name: Soares, M. C. Rabello
name: Barbosa, M.
name: Domingues, M.
name: Rigozo, N.
name: Mendes, O.
name: Jauer, P.
name: Dallaqua, R.
name: Branco, R. H.
name: Stekel, T.
name: Gonzalez, W.
name: Kabata, W.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We describe the preliminary design of a magnetograph and visible-light imager instrument to study the solar dynamo processes through observations of the solar surface magnetic field distribution. The instrument will provide measurements of the vector magnetic field and of the line-of-sight velocity in the solar photosphere. As the magnetic field anchored at the solar surface produces most of the structures and energetic events in the upper solar atmosphere and significantly influences the heliosphere, the development of this instrument plays an important role in reaching the scientific goals of The Atmospheric and Space Science Coordination (CEA) at the Brazilian National Institute for Space Research (INPE). In particular, the CEA's space weather program will benefit most from the development of this technology. We expect that this project will be the starting point to establish a strong research program on Solar Physics in Brazil. Our main aim is acquiring progressively the know-how to build state-of-art solar vector magnetograph and visible-light imagers for space-based platforms to contribute to the efforts of the solar-terrestrial physics community to address the main unanswered questions on how our nearby Star works.
description: 5 pages, 1 figure
Athena Wide Field Imager Key Science Drivers
Creators: name: Rau, Arne
name: Nandra, Kirpal
name: Aird, James
name: Comastri, Andrea
name: Dauser, Thomas
name: Merloni, Andrea
name: Pratt, Gabriel W.
name: Reiprich, Thomas H.
name: Fabian, Andy C.
name: Georgakakis, Antonis
name: Güdel, Manuel
name: Różańska, Agata
name: Sanders, Jeremy S.
name: Sasaki, Manami
name: Vaughan, Simon
name: Wilms, Jörn
name: Meidinger, Norbert
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The Wide Field Imager (WFI) is one of two instruments for the Advanced Telescope for High-ENergy Astrophysics (Athena). In this paper we summarise three of the many key science objectives for the WFI - the formation and growth of supermassive black holes, non-gravitational heating in clusters of galaxies, and spin measurements of stellar mass black holes - and describe their translation into the science requirements and ultimately instrument requirements. The WFI will be designed to provide excellent point source sensitivity and grasp for performing wide area surveys, surface brightness sensitivity, survey power, and absolute temperature and density calibration for in-depth studies of the outskirts of nearby clusters of galaxies and very good high-count rate capability, throughput, and low pile-up, paired with very good spectral resolution, for detailed explorations of bright Galactic compact objects.
description: 11 pages, 10 figures, 1 table, SPIE Astronomical Telescopes and Instrumentation, Edinburgh (26 June - 1 July, 2016)
The distribution and kinematics of interstellar O~{\small VI} in the Milky Way}
Creators: name: Sarma, Rathin
name: Pathak, Amit
name: Murthy, Jayanta
name: Sarma, Jayanta K.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present the results of a survey of interstellar O~{\small VI} absorption in the Milky Way (MW) towards {69} stars in the Large Magellanic Cloud (LMC) obtained with the \textit{Far Ultraviolet Spectroscopic Explorer (FUSE)}. The integrated MW O~{\small VI} column densities log N(O~{\small VI}) are in the range from 13.68 to 14.73 with a mean of {14.26$_{-0.09}^{+0.07}$} atoms cm$^{-2}$. The O~{\small VI} exponential scale height is found to be {2.28$\pm$1.06} kpc. The O~{\small VI} column density correlates with the Doppler parameter $\it b$. The O~{\small VI} velocity dispersion ranges from {14.0 to 91.6 with an average value of 62.7 km s$^{-1}$}. These high values of velocity dispersion reveal the effect of turbulence, multiple velocity components and collision on broad O~{\small VI} profiles. There is a significant variation of O~{\small VI} column density on all scales studied {(0.0025$\degr$ - 6.35$\degr$)}. The smallest scale for which O~{\small VI} column density variations has been found is {$\bigtriangleup θ$ $\sim$~9$\arcsec$}. Comparison of the O~{\small VI} velocity profiles with Fe~{\small II} indicates the presence of intermediate velocity cloud (IVC) and/or high velocity cloud (HVC) components in the O~{\small VI} absorption.
description: 6 figures, 3 tables, accepted for publication in MNRAS
PRIVAT Item Bank
Creators: name: Hooijmans, Carlijn R.
name: Whaley, Paul
Publisher: name: OSF Registries
Year: 2023
Subjects: subject: Pharmacology, Toxicology and Environmental Health
subject: Medicine and Health Sciences
subject: Life Sciences
subject: Research Methods in Life Sciences
subject: in vitro
subject: peer-review
subject: risk of bias
subject: study appraisal

description: A method for literature-based discovery of assessment criteria for in vitro studies. An "item bank" of criteria that is the result of following the method
Developments in Maximum Likelihood Unit Root Tests
Creators: name: Zhang, Ying
name: Yu, H.
name: McLeod, A. I.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Statistics Theory (math.ST)
subject: FOS: Mathematics
subject: 62M10, 91B84

description: The exact maximum likelihood estimate (MLE) provides a test statistic for the unit root test that is more powerful \citep[p. 577]{Fuller96} than the usual least squares approach. In this paper a new derivation is given for the asymptotic distribution of this test statistic that is simpler and more direct than the previous method. The response surface regression method is used to obtain a fast algorithm that computes accurate finite-sample critical values. This algorithm is available in the R package {\tt mleur} that is available on CRAN. The empirical power of the new test is shown to be much better than the usual test not only in the normal case but also for innovations generated from an infinite variance stable distribution as well as for innovations generated from a GARCH$(1,1)$ process.
description: 23 page, 4 figures, 1 table
Coupled spatial multi-mode solitons in microcavity wires
Creators: name: Slavcheva, G.
name: Gorbach, A. V.
name: Pimenov, A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: A modal expansion approach is developed and employed to investigate and elucidate the nonlinear mechanism behind the multistability and formation of coupled multi-mode polariton solitons in microcavity wires. With pump switched on and realistic dissipation parameters, truncating the expansion up to the second-order wire mode, our model predicts two distinct coupled soliton branches: stable and ustable. Modulational stability of the homogeneous solution and soliton branches stability are studied. Our simplified 1D model is in remarkably good agreement with the full 2D mean-field Gross-Pitaevskii model, reproducing correctly the soliton existence domain upon variation of pump amplitude and the onset of multistability.
description: 17 pages, 61 figures
Complex systems: physics beyond physics
Creators: name: Holovatch, Yurij
name: Kenna, Ralph
name: Thurner, Stefan
Publisher: name: arXiv
Year: 2016
Subjects: subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: Complex systems are characterized by specific time-dependent interactions among their many constituents. As a consequence they often manifest rich, non-trivial and unexpected behavior. Examples arise both in the physical and non-physical world. The study of complex systems forms a new interdisciplinary research area that cuts across physics, biology, ecology, economics, sociology, and the humanities. In this paper we review the essence of complex systems from a physicist's point of view, and try to clarify what makes them conceptually different from systems that are traditionally studied in physics. Our goal is to demonstrate how the dynamics of such systems may be conceptualized in quantitative and predictive terms by extending notions from statistical physics and how they can often be captured in a framework of co-evolving multiplex network structures. We mention three areas of complex-systems science that are currently studied extensively, the science of cities, dynamics of societies, and the representation of texts as evolutionary objects. We discuss why these areas form complex systems in the above sense. We argue that there exists plenty of new land for physicists to explore and that methodical and conceptual progress is needed most.
description: 22 pages, no figures
Origin of the Characteristic X-ray Spectral Variations of IRAS 13224$-$3809
Creators: name: Yamasaki, Hiroki
name: Mizumoto, Misaki
name: Ebisawa, Ken
name: Sameshima, Hiroaki
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The Narrow-line Seyfert 1 galaxy (NLS1) IRAS 13224$-$3809 is known to exhibit significant X-ray spectral variation, a sharp spectral drop at $\sim$ 7 keV, strong soft excess emission, and a hint of iron L-edge feature, which is very similar to the NLS1 1H 0707$-$495. We have proposed the "Variable Double Partial Covering (VDPC) model" to explain the energy spectra and spectral variability of 1H 0707$-$495 (Mizumoto, Ebisawa and Sameshima 2014, PASJ, 66, 122). In this model, the observed flux/spectral variations below 10 keV within a $\sim$day are primarily caused by change of the partial covering fraction of patchy clouds composed by double absorption layers in the line of sight. In this paper, we apply the VDPC model to IRAS 13224$-$3809. Consequently, we have found that the VDPC model can explain the observed spectral variations of IRAS 13224$-$3809 in the 0.5$-$10 keV band. In particular, we can explain the observed Root Mean Square (RMS) spectra (energy dependence of the fractional flux variation) in the entire 0.5$-$10 keV band. In addition to the well-known significant drop in the iron K-band, we have found intriguing iron L-peaks in the RMS spectra when the iron L-edge is particularly deep. This feature, which is also found in 1H 0707$-$495, is naturally explained with the VDPC model, such that the RMS variations increase at the energies where optical depths of the partial absorbers are large. The absorbers have a larger optical depth at the iron L-edge than in the adjacent energy bands, thus a characteristic iron L-peak appears. On the other hand, just below the iron K-edge, the optical depth is the lowest and the RMS spectrum has a broad dip.
description: 18 pages, 10 figures, Accepted for PASJ
Upper Bounds for the Poincaré Recurrence Time in Quantum Mixed States
Creators: name: Gimeno, Vicent
name: Sotoca, José M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: In this paper by using geometric techniques, we provide upper bounds for the Poincaré recurrence time of a quantum mixed state with discrete spectrum of energies. In the case of discrete but finite spectrum we obtain two type of upper bounds; one of them depends on the uncertainty in the energy, and the other depends only on the (finite) number of states. In the case of discrete but non-finite spectrum we obtain in the same way two upper bounds defining the number of relevant states according to an statistical measurement. These bounds correspond to two different situations in the quantum recurrence process. The first bound is a recurrence time estimation purely quantum, while the other bound that is related with the number of relevant states survives in the classical limit.
description: 17 pages, 1 figure
Synchronization of cyclic power grids: equilibria and stability of the synchronous state
Creators: name: Xi, Kaihua
name: Dubbeldam, Johan. L. A.
name: Lin, Haixiang
Publisher: name: arXiv
Year: 2016
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: Dynamical Systems (math.DS)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: Synchronization is essential for proper functioning of the power grid. We investigate the synchronous state and its stability for a network with a cyclic topology and with the evolution of the states satisfying the swing equations. We calculate the number of stable equilibria and investigate both the linear and nonlinear stability of the synchronous state. The linear stability analysis shows that the stability of the state, determined by the smallest nonzero eigenvalue, is inversely proportional to the size of the network. The nonlinear stability, which we calculated by comparing the potential energy of the type-1 saddles with that of the stable synchronous state, depends on the network size ($N$) in a more complicated fashion. In particular we find that when the generators and consumers are evenly distributed in an alternating way, the energy barrier, preventing loss of synchronization approaches a constant value. For a heterogeneous distribution of generators and consumers, the energy barrier will decrease with $N$. The more heterogeneous the distribution is, the stronger the energy barrier depends on $N$. Finally, we found that by comparing situations with equal line loads in cyclic and tree networks, tree networks exhibit reduced stability. This difference disappears in the limit of $N\to\infty$. This finding corroborates previous results reported in the literature and suggests that cyclic (sub)networks may be applied to enhance power transfer while maintaining stable synchronous operation.
description: 18 pages, 8 figures, submitted to Chaos in 29 July 2016
Gravitational Waves from the Phase Transition of a Non-linearly Realised Electroweak Gauge Symmetry
Creators: name: Kobakhidze, Archil
name: Manning, Adrian
name: Yue, Jason
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Within the Standard Model with non-linearly realised electroweak symmetry, the LHC Higgs boson may reside in a singlet representation of the gauge group. Several new interactions are then allowed, including anomalous Higgs self-couplings, which may drive the electroweak phase transition to be strongly first-order. In this paper we investigate the cosmological electroweak phase transition in a simplified model with an anomalous Higgs cubic self- coupling. We look at the feasibility of detecting gravitational waves produced during such a transition in the early universe by future space-based experiments. We find that for the range of relatively large cubic couplings, $111~{\rm GeV}~ \lesssim |κ| \lesssim 118~{\rm GeV}$, $\sim $mHz frequency gravitational waves can be observed by eLISA, while BBO will potentially be able to detect waves in a wider frequency range, $0.1-10~$mHz.
description: 18 pages
TensiStrength: Stress and relaxation magnitude detection for social media texts
Creators: name: Thelwall, Mike
Publisher: name: arXiv
Year: 2016
Subjects: subject: Computation and Language (cs.CL)
subject: FOS: Computer and information sciences

description: Computer systems need to be able to react to stress in order to perform optimally on some tasks. This article describes TensiStrength, a system to detect the strength of stress and relaxation expressed in social media text messages. TensiStrength uses a lexical approach and a set of rules to detect direct and indirect expressions of stress or relaxation, particularly in the context of transportation. It is slightly more effective than a comparable sentiment analysis program, although their similar performances occur despite differences on almost half of the tweets gathered. The effectiveness of TensiStrength depends on the nature of the tweets classified, with tweets that are rich in stress-related terms being particularly problematic. Although generic machine learning methods can give better performance than TensiStrength overall, they exploit topic-related terms in a way that may be undesirable in practical applications and that may not work as well in more focused contexts. In conclusion, TensiStrength and generic machine learning approaches work well enough to be practical choices for intelligent applications that need to take advantage of stress information, and the decision about which to use depends on the nature of the texts analysed and the purpose of the task.
description: Thelwall, M. (in press). TensiStrength: Stress and relaxation magnitude detection for social media texts. Information Processing & Management
The third moment for the parabolic Anderson model
Creators: name: Chen, Le
Publisher: name: arXiv
Year: 2016
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 60H15, 35R60

description: In this paper, we study the {\it parabolic Anderson model} starting from the Dirac delta initial data: \[ \left(\frac{\partial}{\partial t} -\fracν{2}\frac{\partial^2}{\partial x^2} \right) u(t,x) = λu(t,x) \dot{W}(t,x), \qquad u(0,x)=δ_0(x), \quad x\in\mathbb{R}, \] where $\dot{W}$ denotes the space-time white noise. By evaluating the threefold contour integral in the third moment formula by Borodin and Corwin [2], we obtain some explicit formulas for $\mathbb{E}[u(t,x)^3]$. One application of these formulas is given to show the exact phase transition for the intermittency front of order three.
description: 16 pages, 6 figures
Is the tautochrone curve unique?
Creators: name: Terra, Pedro
name: Souza, Reinaldo de Melo e
name: Farina, C.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: The answer to this question is no. In fact, in addition to the solution first obtained by Christiaan Huygens in 1658, given by the cycloid, we show that there is an infinite number of tautochrone curves. With this goal, we start by briefly reviewing an the problem of finding out the possible potential energies that lead to periodic motions of a particle whose period is a given function of its mechanical energy. There are infinitely many solutions, called sheared potentials. As an interesting example, we show that a Pöschl-Teller and the one-dimensional Morse potentials are sheared relative to one another for negative energies, clarifying why they share the same periods of oscillations for their bounded solutions. We then consider periodic motions of a particle sliding without friction over a track around its minimum under the influence of an uniform gravitational field. After a brief historical survey of the tautochrone problem we show that, given the period of oscillations, there is an infinity of tracks which lead to the same periods. As a bonus, we show that there are infinitely many tautochrones.
description: Accepted for publication in the American Journal of Physics
A Computational Framework for Automation of Point Defect Calculations
Creators: name: Goyal, Anuj
name: Gorai, Prashun
name: Peng, Haowei
name: Lany, Stephan
name: Stevanovic, Vladan
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: A complete and rigorously validated open-source Python framework to automate point defect calculations using density functional theory has been developed. The framework provides an effective and efficient method for defect structure generation, and creation of simple yet customizable workflows to analyze defect calculations. The package provides the capability to compute widely-accepted correction schemes to overcome finite-size effects, including (1) potential alignment, (2) image-charge correction, and (3) band filling correction to shallow defects. Using Si, ZnO and In$_2$O$_3$ as test examples, we demonstrate the package capabilities and validate the methodology.
Citation score normalized by cited references (CSNCR): The introduction of a new citation impact indicator
Creators: name: Bornmann, Lutz
name: Haunschild, Robin
Publisher: name: arXiv
Year: 2016
Subjects: subject: Digital Libraries (cs.DL)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: In this paper, a new field-normalized indicator is introduced, which is rooted in early insights in bibliometrics, and is compared with several established field-normalized indicators (e.g. the mean normalized citation score, MNCS, and indicators based on percentile approaches). Garfield (1979) emphasizes that bare citation counts from different fields cannot be compared for evaluative purposes, because the "citation potential" can vary significantly between the fields. Garfield (1979) suggests that "the most accurate measure of citation potential is the average number of references per paper published in a given field". Based on this suggestion, the new indicator is basically defined as follows: the citation count of a focal paper is divided by the mean number of cited references in a field to normalize citations. The new indicator is called citation score normalized by cited references (CSNCR). The theoretical analysis of the CSNCR shows that it has the properties of consistency and homogeneous normalization. The close relation of the new indicator to the MNCS is discussed. The empirical comparison of the CSNCR with other field-normalized indicators shows that it is slightly poorer able to field-normalize citation counts than other cited-side normalized indicators (e.g. the MNCS), but its results are favorable compared to two citing-side indicator variants (SNCS indicators). Taken as a whole, the results of this study confirm the ability of established indicators to field-normalize citations.
description: Accepted for publication in the Journal of Informetrics
Large scale quantum walks by means of optical fiber cavities
Creators: name: Boutari, J.
name: Feizpour, A.
name: Barz, S.
name: Di Franco, C.
name: Kim, M. S.
name: Kolthammer, W. S.
name: Walmsley, I. A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We demonstrate a platform for implementing quantum walks that overcomes many of the barriers associated with photonic implementations. We use coupled fiber-optic cavities to implement time-bin encoded walks in an integrated system. We show that this platform can achieve very low losses combined with high-fidelity operations, enabling an unprecedented large number of steps in a passive system, as required for scenarios with multiple walkers. Furthermore the platform is reconfigurable, enabling variation of the coin, and readily extends to multidimensional lattices. We demonstrate variation of the coin bias experimentally for three different values.
Hyperbolic decay time series
Creators: name: McLeod, A. Ian
Publisher: name: arXiv
Year: 2016
Subjects: subject: Statistics Theory (math.ST)
subject: FOS: Mathematics
subject: 62M10, 91B84

description: Hyperbolic decay time series such as, fractional Gaussian noise (FGN) or fractional autoregressive moving-average (FARMA) process, each exhibit two distinct types of behaviour: strong persistence or antipersistence. Beran (1994) characterized the family of strongly persistent time series. A more general family of hyperbolic decay time series is introduced and its basic properties are characterized in terms of the autocovariance and spectral density functions. The random shock and inverted form representations are derived. It is shown that every strongly persistent series is the dual of an antipersistent series and vice versa. The asymptotic generalized variance of hyperbolic decay time series with unit innovation variance is shown to be infinite which implies that the variance of the minimum mean-square error one-step linear predictor using the last $k$ observations decays slowly to the innovation variance as $k$ gets large.
description: 16 pages, 1 table
Numerical analysis of homogeneous and inhomogeneous intermittent search strategies
Creators: name: Schwarz, Karsten
name: Schröder, Yannick
name: Rieger, Heiko
Publisher: name: arXiv
Year: 2016
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: A random search is a stochastic process representing the random motion of a particle (denoted as the searcher) that is terminated when it reaches (detects) a target particle or area the first time. In intermittent search the random motion alternates between two or more motility modes, one of which is non-detecting. An example is the slow diffusive motion as the detecting mode and fast, directed ballistic motion as the non-detecting mode, which can lead to much faster detection than a purely diffusive search. The transition rate between the diffusive and the ballistic mode (and back) together with the probability distribution of directions for the ballistic motion defines a search strategy. If these transition rates and/or probability distributions depend on the spatial coordinates within the search domain it is a spatially inhomogeneous search strategy, if both are constant, it is a homogeneous one. Here we study the efficiency, measured in terms of the mean first-passage time, of spatially homogeneous and inhomogeneous search strategies for three paradigmatic search problems: 1) the narrow escape problem, where the searcher has to find a small area on the boundary of the search domain, 2) reaction kinetics, which involves the detection of an immobile target in the interior of a search domain, and 3) the reaction-escape problem, where the searcher first needs to find a diffusive target before it can escape through a narrow region on the boundary. Using families of spatially inhomogeneous search strategies, partially motivated by the spatial organization of the cytoskeleton in living cells with a centrosome, we show that they can be made almost always more efficient than homogeneous strategies.
description: 31 pages, 29 figures
The Local Ginzburg-Rallis Model Over Complex Field
Creators: name: Wan, Chen
Publisher: name: arXiv
Year: 2016
Subjects: subject: Representation Theory (math.RT)
subject: Number Theory (math.NT)
subject: FOS: Mathematics

description: We consider the local Ginzburg-Rallis model over complex field. We show that the multiplicity is always 1 for a majority of the generic representations. We also have partial results on the real case for general generic representations. This is a sequel work of [Wan15] and [Wan16] on which we considered the p-adic case and the real case for tempered representations.
description: 17 pages. arXiv admin note: text overlap with arXiv:1608.03840
Affordable echelle spectroscopy of the eccentric HAT-P-2, WASP-14 and XO-3 planetary systems with a sub-meter-class telescope
Creators: name: Garai, Z.
name: Pribulla, T.
name: Hambálek, Ľ.
name: Kundra, E.
name: Vaňko, M.
name: Raetz, S.
name: Seeliger, M.
name: Marka, C.
name: Gilbert, H.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: A new off-shelf low-cost echelle spectrograph was installed recently on the 0.6m telescope at the Stará Lesná Observatory (Slovakia). In this paper we describe in details the radial velocity (RV) analysis of the first three transiting planetary systems, HAT-P-2, WASP-14 and XO-3, observed with this instrument. Furthermore, we compare our data with the RV data achieved with echelle spectrographs of other sub-meter-, meter- and two-meter-class telescopes in terms of their precision. Finally, we investigate the applicability of our RV data for modeling orbital parameters.
description: AN accepted
Light dynamics in nonlinear trimers and twisted multicore fibers
Creators: name: Castro-Castro, Claudia
name: Shen, Yannan
name: Srinivasan, Gowri
name: Aceves, Alejandro B.
name: Kevrekidis, Panayotis G.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Optics (physics.optics)
subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Physical sciences

description: Novel photonic structures such as multi-core fibers and graphene based arrays present unique opportunities to manipulate and control the propagation of light. Here we discuss nonlinear dynamics for structures with a few (2 to 6) elements for which linear and nonlinear properties can be tuned. Specifically we show how nonlinearity, coupling, and parity-time PT symmetric gain/loss relate to existence, stability and in general, dynamical properties of nonlinear optical modes. The main emphasis of our presentation will be on systems with few degrees of freedom, most notably couplers, trimers and generalizations thereof to systems with 6 nodes.
description: 11 pages, 5 figures, Submitted to JNOPM
On the L^q Dimensions of Measures on Hueter-Lalley Type Self-Affine Sets
Creators: name: Fraser, Jonathan
name: Kempton, Tom
Publisher: name: arXiv
Year: 2016
Subjects: subject: Dynamical Systems (math.DS)
subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Mathematics

description: We study the L^q -dimensions of self-affine measures and the Kaenmaki measure on a class of self-affine sets similar to the class considered by Hueter and Lalley. We give simple, checkable conditions under which the Lq -dimensions are equal to the value predicted by Falconer for a range of q. As a corollary this gives a wider class of self-affine sets for which the Hausdorff dimension can be explicitly calculated. Our proof combines the potential theoretic approach developed by Hunt and Kaloshin with recent advances in the dynamics of self-affine sets.
description: 16 pages
Contamination from a nearby star cannot explain the anomalous transmission spectrum of the ultra-short period giant planet WASP-103b
Creators: name: Southworth, John
name: Evans, Daniel F.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The planet in the WASP-103 system is an excellent candidate for transmission spectroscopy because of its large radius and high temperature. Application of this technique found a variation of radius with wavelength which was far too strong to be explained by scattering processes in the planetary atmosphere. A faint nearby star was subsequently detected, whose contamination of the transit light curves might explain this anomaly. We present a reanalysis of published data in order to characterise the faint star and assess its effect on the measured transmission spectrum. The faint star has a mass of 0.72 +/- 0.08 Msun and is almost certainly gravitationally bound to the planetary system. We find that its effect on the measured physical properties of the planet and host star is small, amounting to a planetary radius larger by 0.6 sigma and planetary density smaller by 0.8 sigma. Its influence on the measured transmission spectrum is much greater: the spectrum now has a minimum around 760 nm and opacity rises to both bluer and redder wavelengths. It is a poor match to theoretical spectra and the spectral slope remains too strong for Rayleigh scattering. The existence of the faint nearby star cannot therefore explain the measured spectral properties of this hot and inflated planet. We advocate further observations of the system, both with high spatial resolution in order to improve the measured properties of the faint star, and with higher spectral resolution to confirm the anomalous transmission spectrum of the planet.
description: Accepted for publication in MNRAS. 8 pages, 5 colour figures, 3 tables
Design of FELiChEM, the first infrared free-electron laser user facility in China
Creators: name: Li, He-Ting
name: Jia, Qi-Ka
name: Zhang, Shan-Cai
name: Wang, Lin
name: Yang, Yong-Liang
Publisher: name: arXiv
Year: 2016
Subjects: subject: Accelerator Physics (physics.acc-ph)
subject: FOS: Physical sciences

description: FELiChEM is a new experimental facility under construction at University of Science and Technology of China (USTC), whose core device is two free electron laser oscillators generating middle-infrared and far-infrared laser and covering the spectral range of 2.5-200 $μ$m. It will be a dedicated infrared light source aiming at energy chemistry research. We present the brief design of FEL oscillators with the emphasis put on the middle-infrared oscillator. Most of the basic parameters are determined and the anticipated performance of the output radiation is given. The first light of FELiChEM is targeted for the end of 2017.
description: 7 pages, 8 figures