cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
High-resolution abundance analysis of red giants in the metal-poor bulge globular cluster HP~1
Creators: name: Barbuy, B.
name: Cantelli, E.
name: Vemado, A.
name: Ernandes, H.
name: Ortolani, S.
name: Saviane, I.
name: Bica, E.
name: Minniti, D.
name: Dias, B.
name: Momany, Y.
name: Hill, V.
name: Zoccali, M.
name: Siqueira-Mello, C.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The globular cluster HP~1 is projected at only 3.33 degrees from the Galactic center. Together with its distance, this makes it one of the most central globular clusters in the Milky Way. It has a blue horizontal branch (BHB) and a metallicity of [Fe/H]~-1.0. This means that it probably is one of the oldest objects in the Galaxy. Abundance ratios can reveal the nucleosynthesis pattern of the first stars as well as the early chemical enrichment and early formation of stellar populations. High-resolution spectra obtained for six stars were analyzed to derive the abundances of the light elements C, N, O, Na, and Al, the alpha-elements Mg, Si, Ca, and Ti, and the heavy elements Sr, Y , Zr, Ba, La, and Eu.} High-resolution spectra of six red giants that are confirmed members of the bulge globular cluster HP~1 were obtained with the 8m VLT UT2-Kueyen telescope with the UVES spectrograph in FLAMES-UVES configuration. The spectroscopic parameter derivation was based on the excitation and ionization equilibrium of FeI and FeII. We confirm a mean metallicity of [Fe/H] = -1.06~0.10, by adding the two stars that were previously analyzed in HP~1. The alpha-elements O and Mg are enhanced by about +0.3
description: 15 pages, 8 figures In press in Astronomy & Astrophysics (2016)
Comparative Analysis of Module Temperature Measurements and Estimation Methods for Various Climate Zones across the Globe
Creators: name: Vidal De Oliveira, A.K.
name: Braga, M.
name: Burnham, L.
name: Dittmann, S.
name: Gottschalg, R.
name: Betts, T.R.
name: Rodríguez-Gallegos, C.D.
name: Reindl, T.
name: Oh, S.-Y.
name: Rüther, R.
Publisher: name: WIP
Year: 2020
Subjects: PV Systems and Storage – Modelling, Design, Operation and Performance
Operation, Performance and Maintenance of PV Systems

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 1345-1351
description: Photovoltaic (PV) back-of- module (BoM) temperature measurements or estimations are key factors for the performance analysis and modeling of photovoltaic (PV) systems. Accurate module temperature estimation leads to more accurate energy yield predictions that are key determinants of investment value. Even though temperature prediction models have been investigated for decades, no studies analyzing the accuracy of different temperature estimation models across a wide range of climatic conditions have been identified prior to the work described here. This paper compares PV module temperature measurements and temperatures estimated through two methods (the so-called Ross’s and Faiman’s models) at multiple sites worldwide. Results showed that both models performed similarly at all sites and for different PV module technologies, with the exception of one test site in Germany, where the Faiman’s model outperformed the Ross model The test site in the United Kingdom presented the smallest differences between measured and estimated temperatures, possibly due to the fixation method of this site’s temperature sensor, that was cocooned with gas-flue silicone adhesive sealant on the back of the module. Results also showed that, for both models analyzed, all sites presented larger errors for higher irradiance levels, with the largest margin of error seen at the Brazilian test site.
Guidelines for Ensuring Data Quality for Photovoltaic System Performance Assessment and Monitoring
Creators: name: Livera, A.
name: Theristis, M.
name: Koumpli, E.
name: Makrides, G.
name: Stein, J.S.
name: Georghiou, G.E.
Publisher: name: WIP
Year: 2020
Subjects: PV Systems and Storage – Modelling, Design, Operation and Performance
Operation, Performance and Maintenance of PV Systems

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 1352-1356
description: High-quality datasets are crucial for the performance and reliability analysis of photovoltaic (PV) systems. With respect to data integrity, invalid data are a common problem exhibited in PV monitoring systems. A data pipeline approach was recently introduced aiming to support reproducible results in PV performance. The methodology is expanded in this study by examining further outlier observations in respect to detection techniques, impact and treatment methods. The outlier detection results demonstrated that the standard boxplot rule yielded the highest detection rate of 95.3% (by taking a moving data window) at 40% of outlying data points and the effect of random outlying data points was mitigated by listwise deletion. The comparative analysis of outlying data treatment demonstrated that back-filling with the Sandia Array Performance Model (SAPM) yielded more accurate degradation rate (RD) estimates (absolute percentage error, APE, of up to 0.36% at 40% of outlying data) compared to filtering out the outlying data points (APE of up to 2.53% with listwise deletion).
Leaf from a Missal, Fragment
Creators: name: :Unav
Publisher: name: University of Victoria Libraries
Year: 2020
Subjects: subject: Manuscripts, Medieval
valueUri: http://id.worldcat.org/fast/1008422
subject: Missals
valueUri: http://id.worldcat.org/fast/1023680

description: Missal, England, c.1425-1450. Fragment of a leaf from a large noted Missal with apparatus in red and with musical notation.
Kinematically Detected Halo Streams
Creators: name: Smith, Martin C.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Clues to the origins and evolution of our Galaxy can be found in the kinematics of stars around us. Remnants of accreted satellite galaxies produce over- densities in velocity-space, which can remain coherent for much longer than spatial over-densities. This chapter reviews a number of studies that have hunted for these accretion relics, both in the nearby solar-neighborhood and the more-distant stellar halo. Many observational surveys have driven this field forwards, from early work with the Hipparcos mission, to contemporary surveys like RAVE & SDSS. This active field continues to flourish, providing many new discoveries, and will be revolutionised as the Gaia mission delivers precise proper motions for a billion stars in our Galaxy.
description: 27 pages, 10 figures. Chapter from Springer ASSL Volume entitled "Tidal Streams in the Local Group and Beyond". Affluent readers may wish to purchase the full volume here: http://link.springer.com/book/10.1007/978-3-319-19336-6
Evaluation of Provisional Acceptance Testing Procedures for Commercial PV Plants
Creators: name: Mau, S.
name: Sharpe, A.
name: Campistron, C.
name: Canto Teixeira, F.
name: Chouleur, N.
Publisher: name: WIP
Year: 2020
Subjects: PV Systems and Storage – Modelling, Design, Operation and Performance
Operation, Performance and Maintenance of PV Systems

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 1357-1359
description: In the period following commissioning, commercial PV plants undergo a performance test as part of their Provisional Acceptance Certification (PAC) procedure, in order to demonstrate that performance is in line with contractual requirements. These requirements include, among others, the level of performance guaranteed for PACtesting, the correction procedure of the measured performance and the duration of the test. Based on operational data from ten European PV plants, the impact of these three factors on the probability that a plant passes or fails the test has been systematically analyzed. It has been shown that the probability of passing the test increases with the test duration. Use of a monthly correction improves significantly the probability, while a temperature correction alone has no beneficial impact. If additional correction is used together with a monthly correction, the probability increased from 95% for a 4 days test to 99% for a 16 days test.
Autenticazione d'immagini biomediche
Creators: name: Picco, Romualdo
name: Vernone, Annamaria
Publisher: name: Zenodo
Year: 2009
Subjects: watermarking
autenticazione immagini

description: Le due linee di studio su immagini radiografiche

 R. Picco – CNR-INRIM Istituto Nazionale di Ricerca Metrologica – Torino
 A. Vernone - DGBB Università degli studi di Torino Valutazione con metodi oggettivi ponderati soggettivamente della qualità di un’immagine radiografica Studio di appropriate tecniche di watermarking come strumento per la verifica di conformità, garanzia di riservatezza e certificazione dell’identità del paziente, per applicazioni di tele radiologia digitale
Temporal Dynamics of Connectivity and Epidemic Properties of Growing Networks
Creators: name: Fotouhi, Babak
name: Shirkoohi, Mehrdad Khani
Publisher: name: arXiv
Year: 2015
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Social and Information Networks (cs.SI)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Traditional mathematical models of epidemic disease had for decades conventionally considered static structure for contacts. Recently, an upsurge of theoretical inquiry has strived towards rendering the models more realistic by incorporating the temporal aspects of networks of contacts, societal and online, that are of interest in the study of epidemics (and other similar diffusion processes). However, temporal dynamics have predominantly focused on link fluctuations and nodal activities, and less attention has been paid to the growth of the underlying network. Many real networks grow: online networks are evidently in constant growth, and societal networks can grow due to migration flux and reproduction. The effect of network growth on the epidemic properties of networks is hitherto unknown---mainly due to the predominant focus of the network growth literature on the so-called steady-state. This paper takes a step towards alleviating this gap. We analytically study the degree dynamics of a given arbitrary network that is subject to growth. We use the theoretical findings to predict the epidemic properties of the network as a function of time. We observe that the introduction of new individuals into the network can enhance or diminish its resilience against endemic outbreaks, and investigate how this regime shift depends upon the connectivity of newcomers and on how they establish connections to existing nodes. Throughout, theoretical findings are corroborated with Monte Carlo simulations over synthetic and real networks. The results shed light on the effects of network growth on the future epidemic properties of networks, and offers insights for devising a-priori immunization strategies.
AHP-GIS Suitable Sites Identification for Large-Scale PV Installations: a Case Study in Marrakesh-Safi Region
Creators: name: Ouchani, F.-Z.
name: Jbaihi, O.
name: Maaroufi, M.
name: Ghennioui, A.
Publisher: name: WIP
Year: 2020
Subjects: PV Systems and Storage – Modelling, Design, Operation and Performance
Design and Installation of PV Systems

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 1330-1338
description: In this paper, an assessment of the large-scale Photovoltaic (PV) potential in the region of Marrakesh-Safi, Morocco, has been carried out. Considering the significant solar resources that the country possesses, the purpose of this investigation was to highlight suitable sites for a PV power plant. To this end, Multi-Criteria Decision Making (MCDM) analysis and Geographic Information System (GIS) tools were combined. Several criteria were taken into account, namely the constraints related to the system installation and environmental conditions. To the best of our knowledge, no study has considered the wind speed as a criterion for PV site selection. Such a criterion has a cooling effect on the technology itself and also affects the stability of the PV panel mounting system. Results reveal that 74 % of the study area was considered suitable to host PV power plants. An Analytical Hierarchy Process (AHP) analysis was conducted to evaluate the adopted criteria and a ranking map was generated for the appropriate surface using GIS tools. Results demonstrate that 24.3% of the suitable area was qualified as highly suitable according to calculations. These findings help stakeholders to select the highest ranked sites, ensuring a high score from a technical and economic point of view.
Synodale Elemente im Anglikanismus und in den reformierten Kirchen der Niederlande
Creators: name: Andel, Cornelis Pieter Van
Publisher: name: Concilium
Year: 1970

description: Concilium, Bd. 7 Nr. 3 (1971): Concilium: Internationale Zeitschrift für Theologie, Band 7, Heft 3
Iterative and Self-Consistent Estimation of Degradation and Soiling Loss in PV Systems - a Case Study
Creators: name: Skomedal, A.
name: Deceglie, M.G.
name: Haug, H.
name: Marstein, E.S.
Publisher: name: WIP
Year: 2020
Subjects: PV Systems and Storage – Modelling, Design, Operation and Performance
Operation, Performance and Maintenance of PV Systems

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 1339-1344
description: In many parts of the world, soiling is a significant loss mechanism for PV energy production. Methods for accurately quantifying historical and current soiling losses are needed. Furthermore, state-of-the-art methods to estimate degradation rates based on production data do not handle soiling in a satisfactory manner. In order to accurately estimate either of these quantities, it is in many cases helpful to consider their combined effect on PV system performance. In this work we make use of the Combined Degradation and Soiling (CODS) algorithm, which iteratively decomposes time series of daily normalized energy yield into four components: a soiling ratio, a degradation trend, seasonal variations, and noise. We demonstrate the use of the model on field performance data from a utility-scale power plant in a high-soiling environment in the Middle East. We apply the algorithm to the temperature-corrected performance index of the DC power on inverter level, quantifying how soiling varies over time and through the plant. The irradiation-weighted average soiling loss in this plant is 2.3 %, with a median soiling rate of -0.086 %/day. Between the inverters in the site in study, estimated degradation rates range between -0.86 %/year and -0.15 %/year, with a mean rate of -0.48 %/year.
Relationship between Population Dynamics and the Self-Energy in Driven Non-Equilibrium Systems
Creators: name: Kemper, Alexander F.
name: Freericks, James. K.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We compare the decay rates of excited populations directly calculated within a Keldysh formalism to the equation of motion of the population itself for a Hubbard-Holstein model in two dimensions. While it is true that these two approaches must give the same answer, it is common to make a number of simplifying assumptions within the differential equation for the populations that allows one to interpret the decay in terms of hot electrons interacting with a phonon bath. Here we show how care must be taken to ensure an accurate treatment of the equation of motion for the populations due to the fact that there are identities that require cancellations of terms that naively look like they contribute to the decay rates. In particular, the average time dependence of the Green's functions and self-energies plays a pivotal role in determining these decay rates.
description: Submitted to Entropy
LUD2015-005 RNA-seq reference files
Creators: name: Carroll, Thomas
Publisher: name: figshare
Year: 2023
Subjects: Cancer therapy (excl. chemotherapy and radiation therapy)
Bioinformatic methods development
Translational and applied bioinformatics

description: Tarball containing the reference FASTA and GTF used for the LUD2015-005 study. Supplementary annotation files are also included for QC metric calculation and compatability with our Nextflow pipeline. Use in concert with bitbucket.org/licroxford/carroll_etal_2023 to recreate our RNA-seq alignment pipeline. Instructions in this Bitbucket repository are also provided to recreate the Cell Ranger scRNA-seq reference derived from these reference files.
Measurements of $W^\pm Z$ production cross sections in $pp$ collisions at $\sqrt{s} = 8$ TeV with the ATLAS detector and limits on anomalous gauge boson self-couplings
Creators: name: ATLAS Collaboration
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: This paper presents measurements of $W^\pm Z$ production in $pp$ collisions at a center-of-mass energy of 8 TeV. The gauge bosons are reconstructed using their leptonic decay modes into electrons and muons. The data were collected in 2012 by the ATLAS experiment at the Large Hadron Collider, and correspond to an integrated luminosity of 20.3 fb$^{-1}$. The measured inclusive cross section in the detector fiducial region is $σ_{W^\pm Z \rightarrow \ell^{'} ν \ell \ell} = 35.1 \pm$ 0.9 (stat.) $\pm 0.8$ (sys.) $\pm 0.8$ (lumi.) fb, for one leptonic decay channel. In comparison, the next-to-leading-order Standard Model expectation is 30.0 $\pm$ 2.1 fb. Cross sections for $W^+Z$ and $W^-Z$ production and their ratio are presented as well as differential cross sections for several kinematic observables. Limits on anomalous triple gauge boson couplings are derived from the transverse mass spectrum of the $W^\pm Z$ system. From the analysis of events with a $W$ and a $Z$ boson associated with two or more forward jets an upper limit at 95% confidence level on the $W^\pm Z$ scattering cross section of 0.63 fb, for each leptonic decay channel, is established, while the Standard Model prediction at next-to-leading order is 0.13 fb. Limits on anomalous quartic gauge boson couplings are also extracted.
description: 38 pages plus author list + cover pages (56 pages total), 16 figures, 9 tables. Submitted to Phys. Rev. D. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2014-02/
Employees' Perspective On The Effect Of Supply Chain Management Practices On Organizational Performance: The Case Of Anbessa Shoe Share Company (ASSC)
Creators: name: Hailmariam, Yared
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2017

description: In today's emerging competitive environment, the ultimate success of the business depends on management's ability to integrate the company's intricate network of business relationships. Supply Chain Management is one of the most significant changes in the paradigm of business management that has the potential to make or break a company. Effective supply chain management (SCM) has become a potentially valuable way of securing positive returns for the organization performance since competition is no longer between organizations, but among supply chains. The general objective of this study is to examine the effect of SCM practices on organizational performance with special emphasis on the case company Anbessa Shoe Share Company (ASSC). The study conceptualizes and develops four dimensions of SCM practices: (Supplier Relationship Management, Customer Relationship Management, Information Sharing Practice and Information Technology Adoption Practice) and their effect on organizational performance (Financial as well as market perspectives). The study involved a survey design. A primary data were collect using a closed-ended questionnaire instrument. The data for the study was collected from 102employees of ASSC particularly those who have knowledge about the supply chain management practice using probability sampling particularly stratified sampling technique. The gathered data analyzed using descriptive analytical technique with the help of Statistical Package for Social Sciences (SPSS version 20). The relationships proposed in the framework were tested using Pearson correlation, and the effect of SCM practices on Organizational Performance was analyzed using regression analysis. From the result of the analysis it is concluded that there is a significant positive relationship between SCM practices and organizational performance. Therefore, in order to achieve organizational performance in marketing and financial perspectives in the long-run, it is better for the organization to give due emphasis to SCM practices
Role of the Number of Microtubules in Chromosome Segregation during Cell Division
Creators: name: Bertalan, Zsolt
name: Budrikis, Zoe
name: La Porta, Caterina A. M.
name: Zapperi, Stefano
Publisher: name: arXiv
Year: 2015
Subjects: subject: Biological Physics (physics.bio-ph)
subject: Subcellular Processes (q-bio.SC)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: Faithful segregation of genetic material during cell division requires alignment of chromosomes between two spindle poles and attachment of their kinetochores to each of the poles. Failure of these complex dynamical processes leads to chromosomal instability (CIN), a characteristic feature of several diseases including cancer. While a multitude of biological factors regulating chromosome congression and bi-orientation have been identified, it is still unclear how they are integrated so that coherent chromosome motion emerges from a large collection of random and deterministic processes. Here we address this issue by a three dimensional computational model of motor-driven chromosome congression and bi-orientation during mitosis. Our model reveals that successful cell division requires control of the total number of microtubules: if this number is too small bi-orientation fails, while if it is too large not all the chromosomes are able to congress. The optimal number of microtubules predicted by our model compares well with early observations in mammalian cell spindles. Our results shed new light on the origin of several pathological conditions related to chromosomal instability.
Optimal evolution models for quantum tomography
Creators: name: Czerwiński, Artur
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: The research presented in this article concerns the stroboscopic approach to quantum tomography, which is an area of science where quantum Physics and linear algebra overlap. In this article we introduce the algebraic structure of the parametric-dependent quantum channels for 2-level and 3-level systems such that the generator of evolution corresponding with the Kraus operators has no degenerate eigenvalues. In such cases the index of cyclicity of the generator is equal $1$, which physically means that there exists one observable the measurement of which performed sufficient number of times at distinct instants provides enough data to reconstruct the initial density matrix and, consequently, the trajectory of the state. Necessary conditions for the parameters and relations between them are introduced. The results presented in this paper seem to have considerable potential applications in experiments due to the fact that one can perform quantum tomography by conducting only one kind of measurement. Therefore, the analyzed evolution models can be considered optimal in the context of quantum tomography. Finally, we also introduce some remarks concerning optimal evolution models in case of $n-$dimensional Hilbert space.
Cooperative Planning of Renewable Generations for Interconnected Microgrids
Creators: name: Wang, Hao
name: Huang, Jianwei
Publisher: name: arXiv
Year: 2016
Subjects: subject: Computer Science and Game Theory (cs.GT)
subject: Systems and Control (eess.SY)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: We study the renewable energy generations in Hong Kong based on realistic meteorological data, and find that different renewable sources exhibit diverse time-varying and location-dependent profiles. To efficiently explore and utilize the diverse renewable energy generations, we propose a theoretical framework for the cooperative planning of renewable generations in a system of interconnected microgrids. The cooperative framework considers the self-interested behaviors of microgrids, and incorporates both their long-term investment costs and short-term operational costs over the planning horizon. Specifically, interconnected microgrids jointly decide where and how much to deploy renewable energy generations, and how to split the associated investment cost. We show that the cooperative framework minimizes the overall system cost. We also design a fair cost sharing method based on Nash bargaining to incentivize cooperative planning, such that all microgrids will benefit from cooperative planning. Using realistic data obtained from the Hong Kong observatory, we validate the cooperative planning framework, and demonstrate that all microgrids benefit through the cooperation, and the overall system cost is reduced by 35.9% compared to the noncooperative planning benchmark.
description: To appear in IEEE Transactions on Smart Grid
Right-angled Coxeter groups with n-dimensional Sierpiński compacta as boundaries
Creators: name: Świątkowski, Jacek
Publisher: name: arXiv
Year: 2016
Subjects: subject: Geometric Topology (math.GT)
subject: FOS: Mathematics
subject: 20F67, 20F55, 20F65

description: For arbitrary integer n, we describe a large class of right-angled Coxeter systems for which the visual baundary (of the corresponding Coxeter-Davis complex) is homeomorphic to the n-dimensional Sierpiński compactum. We also provide a necessary and sufficient condition for a planar simplicial complex L under which the right-angled Coxeter system whose nerve is L has the visual boundary homeomorphic to the Sierpiński curve.
description: 25 pages, 1 figure
Benchmarking Yield Assessment Exercise in Different Climates within an International Collaboration Framework
Creators: name: Moser, D.
name: Lindig, S.
name: Herz, M.
name: Müller, B.
name: Horvath, I.
name: Schils, A.
name: Ramesh, S.
name: Green, M.
name: Vedde, J.
name: Barnard, D.
name: Herteleer, B.
name: Tsanakas, J.A.
name: Ascencio-Vásquez, J.
name: Richter, M.
Publisher: name: WIP
Year: 2020
Subjects: PV Systems and Storage – Modelling, Design, Operation and Performance
Design and Installation of PV Systems

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 1317-1323
description: Within the IEA PVPS Task 13, a group of experts representing several leading R&D centers, universities and project developers/EPC companies, is developing a framework for a quantitative analysis of yield assessments (YAs). Several sites were selected in different climates and partners were asked to provide independent yield assessment based on their best practices and/or their own developed simulation tools. The results were analysed and uncertainty reduction scenarios were studied. The final aim is to link the uncertainty framework and the scenarios with cash flow models and Levelized Cost of Energy (LCOE) calculations compared to real case studies.
Low Rank Approximation in $G_0W_0$ Approximation
Creators: name: Shao, Meiyue
name: Lin, Lin
name: Yang, Chao
name: Liu, Fang
name: da Jornada, Felipe H.
name: Deslippe, Jack
name: Louie, Steven G.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Numerical Analysis (math.NA)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: The single particle energies obtained in a Kohn--Sham density functional theory (DFT) calculation are generally known to be poor approximations to electron excitation energies that are measured in transport, tunneling and spectroscopic experiments such as photo-emission spectroscopy. The correction to these energies can be obtained from the poles of a single particle Green's function derived from a many-body perturbation theory. From a computational perspective, the accuracy and efficiency of such an approach depends on how a self energy term that properly accounts for dynamic screening of electrons is approximated. The $G_0W_0$ approximation is a widely used technique in which the self energy is expressed as the convolution of a non-interacting Green's function ($G_0$) and a screened Coulomb interaction ($W_0$) in the frequency domain. The computational cost associated with such a convolution is high due to the high complexity of evaluating $W_0$ at multiple frequencies. In this paper, we discuss how the cost of $G_0W_0$ calculation can be reduced by constructing a low rank approximation to the frequency dependent part of $W_0$. In particular, we examine the effect of such a low rank approximation on the accuracy of the $G_0W_0$ approximation. We also discuss how the numerical convolution of $G_0$ and $W_0$ can be evaluated efficiently and accurately by using a contour deformation technique with an appropriate choice of the contour.
description: The paper has been accepted for publication in SCIENCE CHINA Mathematics
Large-Scale Bifacial PV Test Field Performance Compared to Simulations Using Commercially Available Software, Research-Based and Open Source Tools
Creators: name: Riedel-Lyngskær, N.
name: Berrian, D.
name: Alvarez Mira, D.
name: Protti, A.A.
name: Thorsteinsson, S.
name: Poulsen, P.B.
name: Libal, J.
name: Vedde, J.
Publisher: name: WIP
Year: 2020
Subjects: PV Systems and Storage – Modelling, Design, Operation and Performance
Design and Installation of PV Systems

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 1324-1329
description: The aim of this work is to provide the photovoltaic (PV) community with a validation study of eight tools used to simulate bifacial PV performance. We simulate real 26 kWp bifacial p-PERC arrays located within a 420 kWp site located in Northern Europe (55.6°N, 12.1°E). The substructures investigated include horizontal single axis trackers (HSATs) and fixed tilt racks that have dimensions analogous to those found in utility-scale PV installations. Each bifacial system has a monofacial reference system with similar front side power. We use on-site solar radiation (global, diffuse and beam) and albedo measurements from spectrally flat class A sensors as inputs to the simulation tools, and compare modeled values to field measurements of string level DC power and rear plane of array irradiance. Our results show that state-ofthe-art bifacial performance models add ~0.5% uncertainty to the PV modeling chain. For the site investigated, 2D view factor fixed tilt simulations are within ±1 % of measured monthly bifacial gain. However, simulations of single axis tracker systems are less accurate, wherein 2D view factor and 3D ray tracing are within approximately 2% and 1% of measured bifacial gain, respectively.
Line shifts and sub-pc super-massive binary black holes
Creators: name: Simic, Sasa
name: Popovic, Luka C.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Here we discuss the possibility of super-massive binary black hole (SMBBH) detection, using the shifts of the broad lines emitted from a binary system. We perform a number of simulations of shapes and shifts of $H_β$ lines emitted from SMBBHs, taking into account the emission from two different regions located around both black holes, and kinematical effects which should be present in a SMBBH. In the model we connect the parameters of the lines with the mass of black holes and find that the peak shift depends, not only on kinematical effects of system rotation and black hole mass ratio, but it is also a function of the individual masses of the two black holes (BHs).
description: 10 pages 6 figures
Simulation of Large PV Plants Using a Continuous Radiance Distribution Model and Cell-Resolution Mismatch Calculation
Creators: name: Herrerías Azcué, M.
name: Capdevila, H.
name: Zhou, H.
name: Hammer, A.
Publisher: name: WIP
Year: 2020
Subjects: PV Systems and Storage – Modelling, Design, Operation and Performance
Design and Installation of PV Systems

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 1311-1316
description: The main goal of the present work is to study the sensitivity of shading calculations under a „realistic“ (quasi-continuous) radiance distribution model, as opposed to the „standard“ isotropic assumption. We are interested in the balance between the possible accuracy improvements vs the increased computational expense, assuming the shading calculation is coupled with an accurate electrical mismatch model and applied to large-scale PV systems. Two existing PV plants are modeled under three scenarios: (a) an isotropic 3D view-factor (b) a three-component model (with a horizon-brightening band); and (c) a continuous radiance distribution function modeled as a detailed (43 element) sky-tessellation. To estimate a metric of the sensitivity of the model, a cross comparison of numerical results for a small set of virtual PV plants with diverse configurations and climatic conditions is performed. Finally, indirect validation of the model is attempted by comparison of the simulation output to plant monitoring data, but the data quality and resolution turn out to be completely insufficient to reflect the subtlety of the diffuse shading effect.
Folium from a Medieval Psalter, Fragment
Creators: name: :Unav
Publisher: name: University of Victoria Libraries
Year: 2020
Subjects: subject: Psalters
valueUri: http://id.worldcat.org/fast/1080778
subject: Manuscripts, Medieval
valueUri: http://id.worldcat.org/fast/1008422

description: Folium from a medieval Psalter, Psalm 90:12-91:2, Flemish (Ghent?), c. 1450-1460.
Ambipolar Light-Emitting Transistors on Chemical Vapor Deposited Monolayer MoS2
Creators: name: Ponomarev, Evgeniy
name: Gutiérrez-Lezama, Ignacio
name: Ubrig, Nicolas
name: Morpurgo, Alberto F.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We realize and investigate ionic liquid gated field-effect transistors (FETs) on large-area MoS2 monolayers grown by chemical vapor deposition (CVD). Under electron accumulation, the performance of these devices is comparable to that of FETs based on exfoliated flakes. FETs on CVD-grown material, however, exhibit clear ambipolar transport, which for MoS2 monolayers had not been reported previously. We exploit this property to estimate the bandgap Δ of monolayer MoS2 directly from the device transfer curves and find Δ $\approx$ 2.4-2.7 eV. In the ambipolar injection regime, we observe electroluminescence due to exciton recombination in MoS2, originating from the region close to the hole-injecting contact. Both the observed transport properties and the behavior of the electroluminescence can be consistently understood as due to the presence of defect states at an energy of 250-300 meV above the top of the valence band, acting as deep traps for holes. Our results are of technological relevance, as they show that devices with useful optoelectronic functionality can be realized on large-area MoS2 monolayers produced by controllable and scalable techniques.
Testbed Validation of Bifacial Performance Modelling Methodology Using Ray-Tracing Methods
Creators: name: Phetdee, K.
name: Vorasitchai, V.
name: Donaldson-Balan, M.
name: Stylianou, I.
name: Dagres, P.
name: Velez, S.
name: Larchet, K.
Publisher: name: WIP
Year: 2020
Subjects: PV Systems and Storage – Modelling, Design, Operation and Performance
Design and Installation of PV Systems

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 1298-1304
description: Bifacial PV modules have attracted substantial investment interest in recent years due to the potential for substantial increased yield , at marginally higher costs, compared to conventional PV modules. The assessment of such potential remains a challenge, with the industry yet to reach to a consensus for a methodology to produce a bankable energy yield assessment. The available solar energy modelling tools already incorporate bifacial PV module capabilities, however many adopt simplified models for representing rear-side irradiation conditions, at the cost of increased modelling uncertainty. Energy modelling tools commonly utilize 2D view-factor models which depend on non-validated, user-defined factors for representing rear-side irradiance non-linearity, shading and impact of light transmission through PV modules’ inactive areas. Alternatively, 3D ray-tracing software can be used for detailed modelling of bifacial PV array geometries, and of the complex rear-side irradiance. Ray-tracing methods, which are computationally expensive and complex, are yet to be implemented in commercially-available PV modelling tools, although have been the subject of research. Mott MacDonald developed its own methodology for bifacial PV modelling, utilising Radiance, a ray-tracing software, industry-standard modelling tools, and tools developed in house. The methodology, which has been validated against data obtained from several fixed-tilt testbeds, yielded relative differences on an energy yield-basis of up to a maximum of 0.6% from field-obtained data. This compares favourably against PVsyst which, utilizing a view-factor model, yielded relative differences of up to -7% under default settings. The significantly lower deviations observed indicate the potential of the ray-tracing based tools to provide bankable energy yield assessment for bifacial projects. Testbed-specific factors, such as monitoring system’s operating sensitivity and PV single-axis tracking systems, are being considered for further model validations, as well as the position and number of sensors on the rear-side. Model limitations, such as albedo spatial variation and complex-terrain modelling are further aspects for future development.
Spin-glass like dynamics of ferromagnetic clusters in La$_{0.75}$Ba$_{0.25}$CoO$_3$
Creators: name: Kumar, Devendra
Publisher: name: arXiv
Year: 2016
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We report the magnetization study of the compound La$_{0.75}$Ba$_{0.25}$CoO$_3$ where Ba$^{2+}$ doping is just above the critical limit for percolation of ferromagnetic clusters. The field cooled (FC) and zero field cooled (ZFC) magnetization exhibit a thermomagnetic irreversibility and the ac susceptibility show a frequency dependent peak at the ferromagnetic ordering temperature (T$_C$$\approx$203~K) of the clusters. These features indicate about the presence of a non-equilibrium state below T$_C$. In the non-equilibrium state, the dynamic scaling of the imaginary part of ac susceptibility and the static scaling of the nonlinear susceptibility clearly establish a spin-glass like cooperative freezing of ferromagnetic clusters at 200.9(2)~K. The existence of spin-glass like freezing of ferromagnetic clusters is further substantiated by the ZFC aging and memory experiments. We also observe certain dynamical features which are not present in a typical spin-glass, such as, initial magnetization after ZFC aging first increases and then decreases with the wait time and an imperfect recovery of relaxation in negative temperature cycling experiments. This imperfect recovery transforms to perfect recovery on concurrent field cycling. Our analysis suggests that these additional dynamical features have their origin in inter-cluster exchange interaction and cluster size distribution. The inter-cluster exchange interaction above the magnetic percolation gives a superferromagnetic state in some granular thin films but our results show the absence of typical superferromagnetic like state in La$_{0.75}$Ba$_{0.25}$CoO$_3$.
description: 10 pages, 8 figures
Assessing The Challenges Of Indirect Distribution Channels: The Case Of Ethio Telecom
Creators: name: Bante, Getachew
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2017

description: The purpose of this study is to Assessing the Challenges of Indirect Distribution Channels: The Case of Ethio telecom based on assessing the prior experience of distributing the physical voucher card and SIM card on territory confined bases, basic challenges of distribution channel, main reason for terminating of distribution agreement, the level of conflicts of channels in the distribution activities and support of information system on distributors. In light of this objective, the study employed descriptive research and simple random/probability sampling design employed based on the nature of the target population. Consequently, the study selected a sample of 99 individuals or respondents from 252 populations. The data analyzed on quantitative basis using descriptive statistics. The analysis and finding shows the basic challenges that affect the distribution channel in distributing voucher cards and meeting their targets in SIM card sales like the shorter time in sales, consideration of distribution task as a secondary business, lack of distributors capacity in finance and skill and delay in on-time delivery. The distribution agreements were terminated due to lesser commission to distributors, lack of demand based allocation of voucher cards, less profit for distributors/sub distributors. Lack of motivation and support from Ethio telecom to its channel dealers, special treatment for national distributors, lack of enough demand and penalty on contract violation is applied only on distributors are the main reason for conflicts of channels in the distribution activities. Lack of support for distributors to manage their orders and the system to support distributors and low level of IT knowledge of distributors to implement the system are challenges on distribution activities. Basing on the study, the researcher recommends the Ethio telecom and Distributors should have maintain automated distribution system, provided the credit facility and training, support for distributors, maintain penalty on contract violation for both distributors and Ethio telecom, maintain equal treatment for all distributors and considering the distribution task as a primary business
Achieving translational symmetry in trapped cold ion rings
Creators: name: Li, Hao-Kun
name: Urban, Erik
name: Noel, Crystal
name: Chuang, Alexander
name: Xia, Yang
name: Ransford, Anthony
name: Hemmerling, Boerge
name: Wang, Yuan
name: Li, Tongcang
name: Haeffner, Hartmut
name: Zhang, Xiang
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Spontaneous symmetry breaking is a universal concept throughout science. For instance, the Landau-Ginzburg paradigm of translational symmetry breaking underlies the classification of nearly all quantum phases of matter and explains the emergence of crystals, insulators, and superconductors. Usually, the consequences of translational invariance are studied in large systems to suppress edge effects which cause undesired symmetry breaking. While this approach works for investigating global properties, studies of local observables and their correlations require access and control of the individual constituents. Periodic boundary conditions, on the other hand, could allow for translational symmetry in small systems where single particle control is achievable. Here, we crystallize up to fifteen 40Ca+ ions in a microscopic ring with inherent periodic boundary conditions. We show the ring's translational symmetry is preserved at millikelvin temperatures by delocalizing the Doppler laser cooled ions. This establishes an upper bound for undesired symmetry breaking at a level where quantum control becomes feasible. These findings pave the way towards studying quantum many-body physics with translational symmetry at the single particle level in a variety of disciplines from simulation of Hawking radiation to exploration of quantum phase transitions.
description: 15 pages, 4 figures
Magnetic null points in kinetic simulations of space plasmas
Creators: name: Olshevsky, Vyacheslav
name: Deca, Jan
name: Divin, Andrey
name: Peng, Ivy Bo
name: Markidis, Stefano
name: Innocenti, Maria Elena
name: Cazzola, Emanuele
name: Lapenta, Giovanni
Publisher: name: arXiv
Year: 2015
Subjects: subject: Space Physics (physics.space-ph)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: We present a systematic attempt to study magnetic null points and the associated magnetic energy conversion in kinetic Particle-in-Cell simulations of various plasma configurations. We address three-dimensional simulations performed with the semi-implicit kinetic electromagnetic code iPic3D in different setups: variations of a Harris current sheet, dipolar and quadrupolar magnetospheres interacting with the solar wind; and a relaxing turbulent configuration with multiple null points. Spiral nulls are more likely created in space plasmas: in all our simulations except lunar magnetic anomaly and quadrupolar mini-magnetosphere the number of spiral nulls prevails over the number of radial nulls by a factor of 3-9. We show that often magnetic nulls do not indicate the regions of intensive energy dissipation. Energy dissipation events caused by topological bifurcations at radial nulls are rather rare and short-lived. The so-called X-lines formed by the radial nulls in the Harris current sheet and lunar magnetic anomaly simulations are rather stable and do not exhibit any energy dissipation. Energy dissipation is more powerful in the vicinity of spiral nulls enclosed by magnetic flux ropes with strong currents at their axes (their cross-sections resemble 2D magnetic islands). These null lines reminiscent of Z-pinches efficiently dissipate magnetic energy due to secondary instabilities such as the two-stream or kinking instability, accompanied by changes in magnetic topology. Current enhancements accompanied by spiral nulls may signal magnetic energy conversion sites in the observational data.
description: Nordita program on Magnetic Reconnection in Plasmas 2015