cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Gallager’s random coding exponent for differential space time modulation
Creators: name: Srinivasan, Siddharth K.
Publisher: name: University of British Columbia
Year: 2010

description: In this thesis, we study differential space-time modulation with multiple transmit and receive antennas over a frequency non-selective block fading channel in the absence of channel state information (CSI) at both the transmitter and the receiver. We focus on the analysis of the random coding exponent proposed by Gallager for such spacetime channels employing differential modulation with finite signal sets, and consider multiple symbol differential detection (MSDD) with an observation window size N. The underlying principle of MSDD is to utilize an increased observation window of N > 2 consecutively received space-time samples to yield decision variables on N - 1 spacetime data symbols. We thus take into account the channel memory, and can improve power efficiency over conventional differential detection, which employs N = 2. We extend previous work for a similar setup, in that we consider channels where the fading coherence interval is different from the MSDD observation window N, and can be arbitrary with L independent fading realizations per coding frame. We analyze the effect of arbitrary fading coherence intervals on the random coding exponent, and therefore analyze the achievable performance of coded transmission over block fading channels with low to moderate code lengths, i.e. with decoding delay constraints. In this context we also analyze space-time transmission systems with spatial correlation between antennas. Such an analysis allows for a fair comparison of DSTM with MSDD where the window size may vary but the coded diversity remains fixed. We also devise upper and lower bounds and approximations for the random coding exponent, which allows us to not only bound the achievable performance of such space-time systems but also allows for efficient numerical evaluation of the random coding exponent by limiting the search space for the metric calculation. To this end, we make use of tree-search based sphere decoding algorithms for efficient decoding, and along with novel stopping criteria to control the accuracy of the approximation and correspondingly the computational complexity, we apply these sphere decoders for a reduction in complexity cost upto many orders of magnitude. The presented numerical results provide useful information on the performance of coded differential space-time transmission for short to moderate code lengths.
Jet Properties of Compact Steep-Spectrum Sources and an Eddington-Ratio-Driven Unification Scheme of Jet Radiation in Active Galactic Nuclei
Creators: name: Zhang, Jin
name: Zhang, Hai-Ming
name: Gan, Ying-Ying
name: Yi, Ting-Feng
name: Wang, Jun-Feng
name: Liang, En-Wei
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Compact steep-spectrum sources (CSSs) likely represent a population of young radio-loud active galactic nuclei (AGNs) and have been identified as gamma-ray emitting sources. We present a comprehensive analysis of their gamma-ray emission observed with Fermi/LAT and establish their broadband spectral energy distributions (SEDs). We derive their jet properties by the SED fits with a two-zone leptonic model for radiations from the compact core and large-scale extended region, and explore the possible signature of a unification picture of jet radiation among subclasses of AGNs. We show that the observed gamma-rays of CSSs with significant variability are contributed by the radiation of their compact cores via the inverse Compton process of the torus photons. The derived power-law distribution index of the radiating electrons is p_1~1.5-1.8, magnetic field strength is B~0.15-0.6 G, and Doppler boosting factor is δ~2.8-8.9. Assuming that the jet is composed of electron-positron pairs, the compact cores of CSSs are magnetized and have a high radiation efficiency, similar to that of flat spectrum radio quasars. The six CSSs on average have higher Eddington ratio and black hole mass than those non-GeV-detected CSSs, and they follow the correlation between the jet power in units of Eddington luminosity (P_jet/L_Edd) and Eddington ratio (R_Edd) with other sub-classes of AGNs, P_jet/L_Edd~R_Edd^0.52, indicating that R_Edd would be a key physical driver for the unification scheme of AGN jet radiation.
description: 37 Pages, 11 Figures, 4 Tables, accepted for publication in ApJ
Mean-field treatment of the damping of the oscillations of a 1D Bose gas in an optical lattice
Creators: name: Gea-Banacloche, Julio
name: Rey, Ana Maria
name: Pupillo, Guido
name: Williams, Carl J.
name: Clark, Charles W.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We present a theoretical treatment of the surprisingly large damping observed recently in one-dimensional Bose-Einstein atomic condensates in optical lattices. We show that time-dependent Hartree-Fock-Bogoliubov (HFB) calculations can describe qualitatively the main features of the damping observed over a range of lattice depths. We also derive a formula of the fluctuation-dissipation type for the damping, based on a picture in which the coherent motion of the condensate atoms is disrupted as they try to flow through the random local potential created by the irregular motion of noncondensate atoms. We expect this irregular motion to result from the well-known dynamical instability exhibited by the mean-field theory for these systems. When parameters for the characteristic strength and correlation times of the fluctuations, obtained from the HFB calculations, are substituted in the damping formula, we find very good agreement with the experimentally-observed damping, as long as the lattice is shallow enough for the fraction of atoms in the Mott insulator phase to be negligible. We also include, for completeness, the results of other calculations based on the Gutzwiller ansatz, which appear to work better for the deeper lattices.
description: Extended and revised version, August 2005
Asymmetries in the Non-Mesonic Weak Decay of Polarized Lambda-Hypernuclei
Creators: name: Alberico, W. M.
name: Garbarino, G.
name: Parreno, A.
name: Ramos, A.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Nuclear Theory (nucl-th)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The non-mesonic weak decay of polarized Lambda-hypernuclei is studied for the first time by taking into account, with a Monte Carlo intranuclear cascade code, the nucleon final state interactions. A one-meson-exchange model is employed to describe the Lambda N-> n N processes in a finite nucleus framework. The relationship between the intrinsic Lambda asymmetry parameter a_Λand the asymmetry a^M_Λaccessible in experiments is discussed. A strong dependence of a^M_Λon nucleon final state interactions and detection threshold is obtained. Our results for a^M_Λare consistent with ^{11}_ΛB and ^{12}_ΛC data but disagree with observations in ^5_ΛHe.
description: 4 RevTeX pages, 2 figures
UV-finite scalar field theory with unitarity
Creators: name: Ho, Pei-Ming
name: Tian, Yi-Ya
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this paper we show how to define the UV completion of a scalar field theory such that it is both UV-finite and perturbatively unitary. In the UV completed theory, the propagator is an infinite sum of ordinary propagators. To eliminate the UV divergences, we choose the coefficients and masses in the propagator to satisfy certain algebraic relations, and define the infinite sums involved in Feynman diagram calculation by analytic continuation. Unitarity can be proved relatively easily by Cutkosky's rules. The theory is equivalent to infinitely many particles with specific masses and interactions. We take the $ϕ^4$ theory as an example and demonstrate our idea through explicit Feynman diagram computation.
description: 14 pages, references added
Kraichnan model of passive scalar advection
Creators: name: Andreanov, A. Yu.
name: Komarova, M. V.
name: Nalimov, M. Yu.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: A simple model of a passive scalar quantity advected by a Gaussian non-solenoidal ("compressible") velocity field is considered. Large order asymptotes of quantum-field expansions are investigated by instanton approach. The existence of finite convergence radius of the series is proved, a position and a type of the corresponding singularity of the series in the regularization parameter are determined. Anomalous exponents of the main contributions to the structural functions are resummed using new information about the series convergence and two known orders of the expansion.
description: 21 pages
Axial perturbations of the scalarized Einstein-Gauss-Bonnet black holes
Creators: name: Blázquez-Salcedo, Jose Luis
name: Doneva, Daniela D.
name: Kahlen, Sarah
name: Kunz, Jutta
name: Nedkova, Petya
name: Yazadjiev, Stoytcho S.
Publisher: name: arXiv
Year: 2020
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study the axial perturbations of spontaneously scalarized black holes in Einstein-Gauss-Bonnet (EGB) theories. We consider the nodeless solutions of the fundamental branch of the model studied in [1], which possesses a region of radially stable configurations, as shown in [2]. Here we show that almost all of the radially stable black holes are also stable under axial perturbations. When the axial potential is no longer strictly positive, we make use of the S-deformation method to show stability. As for the radial perturbations, hyperbolicity is lost below a certain critical horizon size for a fixed coupling constant. In the stable region, we determine the spectrum of the quasinormal modes by time evolution and by solving the associated time-independent eigenvalue problem.
description: 17 pages, 6 figures
A method for enhancing the stability and robustness of explicit schemes in astrophysical fluid dynamics
Creators: name: Hujeirat, A. A.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: A method for enhancing the stability and robustness of explicit schemes in computational fluid dynamics is presented. The method is based in reformulating explicit schemes in matrix form, which cane modified gradually into semi or strongly-implicit schemes. From the point of view of matrix-algebra, explicit numerical methods are special cases in which the global matrix of coefficients is reduced to the identity matrix $I$. This extreme simplification leads to severer stability range, hence of their robustness. In this paper it is shown that a condition, which is similar to the Courant-Friedrich-Levy (CFL) condition can be obtained from the stability requirement of inversion of the coefficient matrix. This condition is shown to be relax-able, and that a class of methods that range from explicit to strongly implicit methods can be constructed, whose degree of implicitness depends on the number of coefficients used in constructing the corresponding coefficient-matrices. Special attention is given to a simple and tractable semi-explicit method, which is obtained by modifying the coefficient matrix from the identity matrix $I$ into a diagonal-matrix $D$. This method is shown to be stable, robust and it can be applied to search for stationary solutions using large CFL-numbers, though it converges slower than its implicit counterpart. Moreover, the method can be applied to follow the evolution of strongly time-dependent flows, though it is not as efficient as normal explicit methods. In addition, we find that the residual smoothing method accelerates convergene toward steady state solutions considerably and improves the efficiency of the solution procedure.
description: 33 pages, 15 figures
Impact Parameter Dependence in the Balitsky-Kovchegov Equation
Creators: name: Ikeda, T.
name: McLerran, L.
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the impact parameter dependence of solutions to the Balitsky-Kovchegov (BK) equation. We argue that if the kernel of the BK integral equation is regulated to cutoff infrared singularities, then it can be approximated by an equation without diffusion in impact parameter. For some purposes, when momentum scales large compared to $Λ_{QCD}$ are probed, the kernel may be approximated as massless. In particular, we find that the Froissart bound limit is saturated for physical initial conditions and seem to be independent of the cutoff so long as the cutoff is sufficiently large compared to the momentum scale associated with the large distance falloff of the impact parameter distribution.
description: 15 pages, 7 figures
Les facteurs institutionnels d'engagement des entreprises tchadiennes dans la Responsabilité Sociale des Entreprises en matière de changement climatique
Creators: name: MADJIDINGAM, Ngarénon
name: MAYEGLE NGO, Nguidjol Solange
Publisher: name: Zenodo
Year: 2024
Subjects: changement climatique ; RSE ; facteurs institutionnels ; engagement des entreprises ; motivations.

description: Dans un environnement concurrentiel de plus en plus complexe, caractérisé par la recrudescence des catastrophes naturelles liées au changement climatique, les entreprises doivent s'adapter à ce contexte en l'intégrant dans la mise en œuvre de démarches de Responsabilité Sociale des Entreprises (RSE). 

L'objectif de cet article est d'identifier les facteurs institutionnels qui expliquent l'engagement des entreprises dans la RSE en matière de changement climatique.

Ce travail a permis de construire un modèle de recherche au niveau institutionnel qui explique les motivations réelles d'engagement des entreprises tchadiennes dans la RSE en matière de changement climatique. Le choix de l'approche hypothético-déductive a été fait en adoptant la méthode non probabiliste. La régression logistique a été utilisée pour tester 59 entreprises tchadiennes opérant dans tous les secteurs d'activité. Les résultats ont partiellement confirmé nos hypothèses. Ainsi, l'engagement des entreprises dans la RSE en matière de changement climatique est motivé par : La peur de la réglementation, les attentes des clients et les subventions gouvernementales.
Quantum resolution of black hole singularities
Creators: name: Husain, Viqar
name: Winkler, Oliver
Publisher: name: arXiv
Year: 2004
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study the classical and quantum theory of spherically symmetric spacetimes with scalar field coupling in general relativity. We utilise the canonical formalism of geometrodynamics adapted to the Painleve-Gullstrand coordinates, and present a new quantisation of the resulting field theory. We give an explicit construction of operators that capture curvature properties of the spacetime and use these to show that the black hole curvature singularity is avoided in the quantum theory.
description: 5 pages, version to appear in CQG
RB-The Temporal Context of Family Violence in Victoria
Creators: name: Benier, Kathryn
name: Williamson, Harley
Publisher: name: Monash University
Year: 2020
Subjects: subject: Sociology
subject: FOS: Sociology
subject: 160299 Criminology not elsewhere classified
subject: FOS: Law

description: Key changes into the handling of family violence cases in Victoria emerged from the 2015 release of the national report of the Coalitional of Australian Government Advisory Panel on Reducing Violence Against Women and their Children (COAG 2015), the 2015 inquest findings into Luke Batty’s death (Coroners Court of Victoria, 2015), and the 2016 state-led Royal Commission into Family Violence. These reports and recommendations highlighted the importance of rethinking responses to family violence, including increasing education and training, improving police incident responses, enhancing family violence screening practices, and increasing information sharing between support and criminal justice agencies. In addition, the reform of the Common Risk Assessment Framework (CRAF; now Multi-Agency Risk Assessment and Management Framework, see McCulloch et al 2016) in Victoria has elicited change regarding the prioritisation and process of risk identification, assessment and management.
title: Community KPI-dashboard : a virtual community evaluation methodology
Creators: name: Rubas, Daniel
Publisher: name: TU Wien
Year: 2016
Subjects: subject: virtuelle Gemeinschaften
subject: Key-Performance-Indikatoren
subject: Erfolg
subject: Erfolgsmessung
subject: virtual communities
subject: key-performance-indicators
subject: success
subject: performance measurement

description: This thesis addresses the problem of identifying and measuring success factors of virtual communities. This task is highly relevant since virtual communities are part of today's society and have many different possible applications for enterprises such as involving the customers into the process of developing new products or for marketing to build brand loyalty. But to establish a virtual community can be hard and success is not guaranteed. To increase the success of virtual communities, general success factors as well as keyperformance-indicators shall be identified and different designing methods will be described. This thesis analyzes the success factors of famous virtual communities like Stack Overflow or Wikipedia and previous scientific work dealing with this topic. Based on the literature review and a case study about an online community for exchange students at the technical university of Vienna requirements for the 'Community KPI-Dashboard' were derived. The -Community KPI-Dashboard- is a Drupal module to measure and visualize the identified key-performance-indicators for virtual communities based on Drupal. To achieve this, the reports of the 'Community KPI-Dashboard' were designed and implemented as far as possible on Drupal core and additional functionality was added using other popular Drupal modules for online communities. The reports generated by the -Community KPI-Dashboard- include measures about activity, audience, content, purposes, roles, quality and views in the community as well as a small social network analysis. In the end ideas and approaches for further enhancements and development of the 'Community KPI-Dashboard' are discussed.
Sub-mm detection of a high redshift Type 2 QSO
Creators: name: Mainieri, V.
name: Rigopoulou, D.
name: Lehmann, I.
name: Scott, S.
name: Matute, I.
name: Almaini, O.
name: Tozzi, P.
name: Hasinger, G.
name: Dunlop, J. S.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report on the first SCUBA detection of a Type 2 QSO at z=3.660 in the Chandra Deep Field South. This source is X-ray absorbed, shows only narrow emission lines in the optical spectrum and is detected in the sub-mm: it is the ideal candidate in an evolution scheme for AGN (e.g. Fabian (1999); Page et al. (2004)) of an early phase corresponding to the main growth of the host galaxy and formation of the central black hole. The overall photometry (from the radio to the X-ray energy band) of this source is well reproduced by the spectral energy distribution (SED) of NGC 6240, while it is incompatible with the spectrum of a Type 1 QSO (3C273) or a starburst galaxy (Arp 220). Its sub-mm (850 μm) to X-ray (2 keV) spectral slope (alpha_SX) is close to the predicted value for a Compton-thick AGN in which only 1% of the nuclear emission emerges through scattering. Using the observed flux at 850 μm we have derived a SFR=550--680 M$_odot/yr and an estimate of the dust mass, M$_dust=4.2 10^8 M_odot
description: 6 Pages, 5 Figures, accepted for publication in MNRAS
The Host Galaxies of Tidal Disruption Events
Creators: name: French, K. Decker
name: Wevers, Thomas
name: Law-Smith, Jamie
name: Graur, Or
name: Zabludoff, Ann I.
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Recent studies of Tidal Disruption Events (TDEs) have revealed unexpected correlations between the TDE rate and the large-scale properties of the host galaxies. In this review, we present the host galaxy properties of all TDE candidates known to date and quantify their distributions. We consider throughout the differences between observationally-identified types of TDEs and differences from spectroscopic control samples of galaxies. We focus here on the black hole and stellar masses of TDE host galaxies, their star formation histories and stellar populations, the concentration and morphology of the optical light, the presence of AGN activity, and the extra-galactic environment of the TDE hosts. We summarize the state of several possible explanations for the links between the TDE rate and host galaxy type. We present estimates of the TDE rate for different host galaxy types and quantify the degree to which rate enhancement in some types results in rate suppression in others. We discuss the possibilities for using TDE host galaxies to assist in identifying TDEs in upcoming large transient surveys and possibilities for TDE observations to be used to study their host galaxies.
description: 55 pages, 13 Figures, 7 Tables. Accepted for publication in Springer Space Science Reviews. Chapter in ISSI review "The Tidal Disruption of Stars by Massive Black Holes" vol. 79
A Composable Specification Language for Reinforcement Learning Tasks
Creators: name: Jothimurugan, Kishor
name: Alur, Rajeev
name: Bastani, Osbert
Publisher: name: arXiv
Year: 2020
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: Reinforcement learning is a promising approach for learning control policies for robot tasks. However, specifying complex tasks (e.g., with multiple objectives and safety constraints) can be challenging, since the user must design a reward function that encodes the entire task. Furthermore, the user often needs to manually shape the reward to ensure convergence of the learning algorithm. We propose a language for specifying complex control tasks, along with an algorithm that compiles specifications in our language into a reward function and automatically performs reward shaping. We implement our approach in a tool called SPECTRL, and show that it outperforms several state-of-the-art baselines.
title: Learning systems and communities of practice for environmental decision making
Creators: name: Blackmore, Chris
Publisher: name: The Open University
Year: 2009

description: This thesis explores learning for environmental decision making (EDM), from the viewpoints of what and who provide necessary support, and how and why practitioners engage in learning for EDM.

 Learning systems and communities of practice (CoPs) are the two main concepts used to frame and interpret the research. The empirical focus is on the experiences of practitioners involved in a UKbased Masters level course and a European research project, from a 'learning for EDM' perspective. The study draws on a range of learning and systems theories and is informed by analysis of discourses of environmental and social learning. Conducting two main inquiries – one course-based, the other project-based – proved to be an effective way of researching in the multiorganisational contexts that are characteristic of EDM.

 Commonalities are identified among different individuals' professional and personal learning for EDM and means of support. Leverage points are recognised where future support might usefully be deployed and design for learning focused. Three models of learning systems are developed to help explore dynamic processes of learning. These are (i) a model of interdependent levels of change (ii) an extension of Vickers' appreciative systems model and (iii) trajectory diagrams. A theoretical framework for systemic analysis of learning for EDM is also proposed, including a generic form.

 The study reveals the importance of the direct study of learners' perspectives, the incremental nature of social learning over time and that engagement with environmental issues is mediated by transformations that are socially negotiated. Both learning systems and CoPs perspectives highlight the interconnections and relationships of importance to learning for EDM. They also provide a means for considering practices and practitioners as a duality. The thesis concludes that both learning systems and CoPs offer 'know-how' that is required to support learning for EDM in future.
Random-Walk Statistics and the Spherical Harmonic Representation of CMB Maps
Creators: name: Stannard, Andrew
name: Coles, Peter
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We investigate the properties of the (complex) coefficients obtained in a spherical harmonic representation of temperature maps of the cosmic microwave background (CMB). We study the effect of the coefficient phase only, as well as the combined effects of phase and amplitude. The method used to check for anomalies is to construct a ``random walk'' trajectory in the complex plane where the step length and direction are given by the amplitude and phase (respectively) of the harmonic coefficient. If the fluctuations comprise a homogeneous and isotropic Gaussian random field on the sky, the path so obtained should be a classical ``Rayleigh flight'' with very well known statistical properties. We illustrate the use of this random-walk representation by using the net walk length as a test statistic, and apply the method to the coefficients obtained from a Wilkinson Microwave Anisotropy Probe (WMAP) preliminary sky temperature map.
description: 5 pages, 1 figure, uses mn.sty. Version accepted for publication in MNRAS. Includes toy models of non-random walks
Percepção dos Consumidores Relativamente à Carne de Bovino: cenários de escolha a partir de grupos de discussão
Creators: name: Viegas, Inês
name: Santos, José Manuel Lima
name: Fontes, Magda Aguiar
name: Viegas, Inês
name: Santos, José Manuel Lima
name: Fontes, Magda Aguiar
Publisher: name: Unknown
Year: 2015
Subjects: subject: Agribusiness
subject: food safety
subject: animal welfare
subject: environment
subject: choice scenarios
subject: focus groups.

description: In developed economies, food safety, animal welfare and the environment have become relevant consumers’ concerns. We conducted several focus groups in two Portuguese cities, Lisboa and Porto, in order to get participants perceptions and concerns for these attributes, which are essentially credence attributes. This knowledge is critical for the subsequent application of stated preference methods. It was also possible to estimate, based on exercises of selection among different meats, and through a logit model, price ranges that could be used in the definition of scenarios for choice experiments (stated preference method).
description: 14
EdgeAI: Leveraging SNNs, Transformers, and Autoencoders for Near-Sensors Intelligence
Creators: name: Busia, Paola
Publisher: name: Zenodo
Year: 2024

description: This talk will explore the cutting-edge advancements in EdgeAI for biosignal analysis, focusing on innovative algorithms such as Spiking Neural Networks (SNNs), Transformers, and Autoencoders. As the demand for real-time, near-sensor processing of biosignals like EEG, ECG, and EMG continues to grow, traditional cloud-based methods face challenges related to latency, energy efficiency, and data privacy. We will discuss how SNNs, with their neuromorphic efficiency, Transformers, with their powerful sequence modelling, and Autoencoders, with their capacity for anomaly spotting, are being adapted for edge deployment. The talk will highlight real-world applications inside and outside the wearable healthcare domain, demonstrating how these technologies enable fast, accurate, and energy-efficient processing at the edge.
On Dual Formulation for Higher Spin Gauge Fields in $(A)dS_d$
Creators: name: Matveev, A. S.
name: Vasiliev, M. A.
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We obtain dual actions for spin $s \geq 2$ massless fields in $(A)dS_d$ by solving different algebraic constraints in the same first-order theory. Flat space dual higher spin actions obtained by Boulanger, Cnockaert and Henneaux \cite{BH} by solving differential constraints are shown to result from our formulation in a sort of quasi-classical approximation for the flat limit. The case of $s=2$ is considered in detail.
description: LaTeX, 13 pages, no figures
Limits on stellar structures in Lovelock theories of gravity
Creators: name: Chakraborty, Sumanta
name: Dadhich, Naresh
Publisher: name: arXiv
Year: 2020
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study the bound on the compactness of a stellar object in pure Lovelock theories of arbitrary order in arbitrary spacetime dimensions, involving electromagnetic field. The bound we derive for a generic pure Lovelock theory, reproduces the known results in four dimensional Einstein gravity. Both the case of a charged shell and that of a charge sphere demonstrates that for a given spacetime dimension, stars in general relativity are more compact than the stars in pure Lovelock theories. In addition, as the strength of the Maxwell field increases, the stellar structures become more compact, i.e., the radius of the star decreases. In the context of four dimensional Einstein-Gauss-Bonnet gravity as well, an increase in the strength of the Gauss-Bonnet coupling (behaving as an effective electric charge), increases the compactness of the star. Implications are discussed.
description: v2, minor revision, published version, 36 pages, 7 figures
Modernização da Agricultura em Moçambique: determinantes da renda agrícola
Creators: name: Guanziroli, Carlos E.
name: Guanziroli, Tomás
name: Guanziroli, Carlos E.
name: Guanziroli, Tomás
Publisher: name: Unknown
Year: 2015
Subjects: subject: Agribusiness
subject: agricultural yield
subject: emergent farmers
subject: fertilizers.

description: The aim of this study is to verify to what extent the technologies coming from the green revolution were effectively adopted in sub-Saharan Africa, and, in cases in which they were adopted, if succeeded in improving agricultural productivity and income. To this end, the work makes first a brief summary of the State of the arts of the green revolution in Africa, showing which countries have advanced more and how the use of chemical fertilizers correlates with productivity increases. The article also discusses the characteristics of the intensification process in a particular case, of Mozambique. Finally, based on micro data of the Agricultural Survey (TIA), an econometric model MQO is tested, aiming to assess the determinants of agricultural income, and, in particular, the use of chemical fertilizers.
title: Actors' inter-organisational information system use within buyer-supplier relationships:Cases from UK retail
Creators: name: Emberson, Caroline
Publisher: name: The Open University
Year: 2009

description: As companies focus on core activities, inter-organisational relationships assume greater importance. This places new demands on cross-boundary, inter-organisational relationships. It is often argued that information and communication technology enables the seamless and efficient flow of information between market-facing organisations and their suppliers. Moving beyond simple market mechanisms based on price, the efficiency and effectiveness of inter-organisational networks can be improved through information sharing. However theory development has been driven largely by organisational-level, single-respondent surveys which have focused on testing competitive performance benefits. Less atention has been paid to how actors' practical inter-organisational information system usage may itself reshape buyer-supplier relationships. The purpose of this resarch is to extend theoretical and practical understanding through a fine-grained exploration of this phenomenon. This study investigated the micro-dynamics of inter-organisational information system use in buyer-supplier relationships in four retail supply networks. This involved a detailed study of operational level behaviour in sixteen organisations. A novel combination of resarch methods was devised to gather data. A form of social change theory was used to analyse the relationship between agency and the use of technological artefacts. The series of accounts which were generated enabled comparison of actors' behaviours under different buyer-supplier conditions. This thesis contributes to knowledge by highlighting how operational actors' creative and selective inter-organisational information system use contributes to system-level supply relationship patterns. Three types of adaptation behaviours were identified. These were labelled as patching ploys, local plots and collaborative conspiracies. Then, at a system-level, four modes of inter-organisational information system use were classified: conformist competition, system utilisation, creative colaboration and competitive innovation. An explanation of the conditions under which actors tend to adopt and engage in one mode rather than another is offered. Finally, the implications for management practice, for theory and for fuure research are discussed.
The response of two BC sawmill communities to the recession of the early 1980s : a newspaper analysis of social capital in the context of economic downturn
Creators: name: Salomons, Kia
Publisher: name: University of British Columbia
Year: 2010

description: This study uses 6 identified dimensions of social capital in Canada to describe and characterize the response of two resource-dependent sawmill communities, Nanaimo and Powell River, British Columbia, during a period of severe economic downturn (1981-1983), using publicly available information found in community newspapers. Social capital is commonly conceptualized as a collective property of social relationships but is most commonly measured as an aggregation of individual survey responses. This study explores whether and how aggregated individual measures of social capital may be manifested in a collective context. A factor analysis of responses to the Equality, Security, Community (ESC) Survey, a representative survey of Canadian adults designed to investigate civil society and the formation of social capital, identified 6 dimensions of social capital in Canada (1). Five of the six dimensions of social capital are composites of cognitive individual measures of social capital, the sixth is a structural measure of community participation. A ’collective’ operational definition was developed for each of the dimensions prior to analyzing the newspaper data. Results show that a structural measure of social capital, namely ’community participation’, was substantially manifested in the newspaper coverage. The two dimensions related to trust - ’government trust’ and ’social trust’ - were not. One dimension, ’economic belief, was manifested in the newspapers of one town, but not the other. Some elements of the dimensions pertaining to perceptions of ’institutional performance’ and to values about ’solidarity’ were manifested in each town. The newspaper coverage on the community’s response was different in each of the two towns. The economic and resulting social structures in the two towns were quite different, as was the degree of relative geographic isolation, and these differences likely affected the nature of the social relationships, which would partly account for the different character of the community response in each town. If social capital is conceptualized as a collective property, a resource that is embedded in relationships that are features of the social structures of society, these results seem to suggest that economic base, degree of isolation, population size and composition and social hierarchy all matter in terms of social capital.
Current-current deformations, conformal integrals and correlation functions
Creators: name: Giribet, Gaston
name: Leoni, Matias
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Motivated by the recent work on $T\bar{T}$-type deformations of 2D CFTs, a especial class of single-trace deformations of AdS$_3$/CFT$_2$ correspondence has been investigated. From the worldsheet perspective, this corresponds to a marginal deformation of the $σ$-model on AdS$_3$ that yields a string background that interpolates between AdS$_3$ and a flat linear dilaton solution. Here, with the intention of studying this worldsheet CFT further, we consider it in the presence of a boundary. In a previous paper, we computed different correlation functions of this theory on the disk, including the bulk 1-point function, the boundary-boundary 2-point function, and the bulk-boundary 2-point function. This led us to compute the anomalous dimension of both bulk and boundary vertex operators, which first required a proper regularization of the ultraviolet divergences of the conformal integrals. Here, we extend the analysis by computing the bulk-bulk 2-point function on the disk and other observables on the sphere. We prove that the renormalization of the vertex operators proposed in our previous works is consistent with the form of the sphere $N$-point functions.
description: 14 pages, 1 figure
Optimal Pricing for Cloud Computing
Creators: name: Eluri, Ramesh
name: Vemula, Rajesh
name: Srikanth, Meda
Publisher: name: figshare
Year: 2020
Subjects: Computer Engineering

description: Cloud applications that offer data management services are emerging. Such clouds support caching of data in order toprovide quality query services. The users can query the cloud data, paying the price for the infrastructure they use. Cloud management necessitates an economy that manages the service of multiple users in an efficient, but also, resource-economic way that allows for cloud profit. Naturally, the maximization of cloud profit given some guarantees for user satisfaction presumes an appropriatepricedemand model that enables optimal pricing of query services. The model should be plausible in that it reflects thecorrelation of cache structures involved in the queries. Optimal pricing is achieved based on a dynamic pricing scheme that adapts to time changes. This paper proposes a novel price-demand model designed for a cloud cache and a dynamic pricing scheme for queries executed in the cloud cache. The pricing solution employs a novel method that estimates the correlations of the cache services in an time-efficient manner. The experimental study shows the efficiency of the solution.
Dynamical evidence of the sub-parsec counter-rotating disc for a close binary of supermassive black holes in the nucleus of NGC 1068
Creators: name: Wang, J. -M.
name: Songsheng, Y. -Y.
name: Li, Y. -R.
name: Du, P.
name: Zhe, Y.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: It arises a puzzle in \NGC\, how to secularly maintain the counter-rotating disc from $0.2$ to $7\,$pc unambiguously detected by recent ALMA observations of molecular gas. Upon further analysis of disc dynamics, we find that the Kelvin-Helmholtz (KH) instability (KHI) results in an unavoidable catastrophe of the disc developed at the interface between the reversely rotating parts, and demonstrate that a close binary of supermassive black holes provides tidal torques as the unique external sources to prevent the disc from the KH catastrophe. We are led to the inescapable conclusion that there must be a binary black hole at the center of NGC 1068, to prevent it from the KH catastrophe. The binary is composed of black holes with a separation of $0.1\,$pc from GRAVITY/VLTI observations, a total mass of $1.3\times 10^{7}\:M_{\odot}$ and a mass ratio of $\sim 0.3$ estimated from the angular momentum budge of the global system. The KHI gives rise to forming a gap without cold gas at the velocity interface which overlaps with the observed gap of hot and cold dust regions. Releases of kinematic energies from the KHI of the disc are in agreement with observed emissions in radio and $γ$-rays. Such a binary is shrinking with a timescale much longer than the local Hubble time via gravitational waves, however, the KHI leads to an efficient annihilation of the orbital angular momentum and speed up merge of the binary, providing a new paradigm of solving the long term issue of "final parsec problem". Future observations of GRAVITY+/VLTI are expected to be able to spatially resolve the CB-SMBHs suggested in this paper.
description: 1 figure, 9pages
Efficient K-Nearest Neighbors Detection Using Complex Secure Assessment Function in Geo Tagged Dataset
Creators: name: Eluri, Ramesh
Publisher: name: figshare
Year: 2020
Subjects: Computer Engineering

description: The materialization of mobile equipment with fast Internet connectivity and geo-tagged capabilities has led to a revolution in personalized position-based services where clients are enabled to admittance information about points of interest that are pertinent to their interests and are also close to their geo tagged coordinates. The important type of queries that absorb location attributes is symbolized by nearest-neighbor queries, where a client wants to retrieve the k- Point of interests that are nearest to the user’s current location. Entities specialized in various areas of interest and gather large amounts of geo-tagged data that appeal to subscribed users. In this paper we proposes development and implementation of frame work to provide more complex protected evaluation method on cipher texts, like skyline queries and security protection guarantees against the client, to prevent it from learning anything other than the received k query results.
3D Continuum radiative transfer in complex dust configurations around young stellar objects and active nuclei II. 3D Structure of the dense molecular cloud core Rho Oph D
Creators: name: Steinacker, J.
name: Bacmann, A.
name: Henning, Th.
name: Klessen, R.
name: Stickel, M.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Constraints on the density and thermal 3D structure of the dense molecular cloud core Rho Oph D are derived from a detailed 3D radiative transfer modeling. Two ISOCAM images at 7 and 15 micron are fitted simultaneously by representing the dust distribution in the core with a series of 3D Gaussian density profiles. Size, total density, and position of the Gaussians are optimized by simulated annealing to obtain a 2D column density map. The projected core density has a complex elongated pattern with two peaks. We propose a new method to calculate an approximate temperature in an externally illuminated complex 3D structure from a mean optical depth. This T(tau)-method is applied to a 1.3 mm map obtained with the IRAM 30m telescope to find the approximate 3D density and temperature distribution of the core Rho Oph D. The spatial 3D distribution deviates strongly from spherical symmetry. The elongated structure is in general agreement with recent gravo-turbulent collapse calculations for molecular clouds. We discuss possible ambiguities of the background determination procedure, errors of the maps, the accuracy of the T(tau)-method, and the influence of the assumed dust particle sizes and properties.
description: 16 pages, 12 figures
title: The rate of profit as a random variable
Creators: name: Wells, Patrick Julian
Publisher: name: The Open University
Year: 2007

description: This thesis is a systematic attempt to investigate two conjectures about the distribution of company rates of profit: that it should be log-normal (Gibrat 1931), and that it should be gamma distributed (Farjoun and Machover 1983).

A large set of company accounts data is analysed, and partial support found for Gibrat and for a generalised version of Farjoun and Machover.

The analysis includes a demonstration of different empirical distributions for different profit rate measures, a demonstration of power law tails in all measures of the profit rate, and a demonstration of size effects (differences in tail weights) in financial ratios. Annual variation in the overall skewness and kurtosis of profit rate distributions is shown to be dominated by variation in the power law tails.

L-moments, a recent innovation in robust methods to deal with extreme values, are used in conjunction with a size-weighted sampling scheme to identify possible models for distributions of the profit rate at the capital level.

Farjoun and Machover derive their hypothesis from a particular conception of the process of capitalist competition. A rival conception, that of Glick (1985), is tested using company accounts data and shown to be vulnerable to criticism concerning the scope of its data set, the test statistic employed, and its choice of profit rate measure. More fundamentally, it is also dependent on doubtful premises about the within-industry distribution of profit rates, as L-moment analysis demonstrates.
A Eficiência das Explorações Leiteiras Micaelenses (Açores)
Creators: name: Almeida, Bruno Aires Da Silva
name: Silva, Emiliana Leonilde Dinis Gil Soares Da
name: Almeida, Bruno Aires Da Silva
name: Silva, Emiliana Leonilde Dinis Gil Soares Da
Publisher: name: Unknown
Year: 2015
Subjects: subject: Agribusiness
subject: Azores
subject: Data Envelopment Analysis
subject: efficiency
subject: milk
subject: models.

description: The discussion of the Common Agricultural Policy is ongoing. One possible scenario is the reduction of support of the Azorean farms. To compensate this loss of income, dairy farmers will improve the efficiency of their farms. This paper aims to estimate the efficiency values and the number of efficient farms in S. Miguel Island, which contributes with 75% of regional production. Milk production in the Azores represents 30% of the Portuguese. This research was going in 91 S. Miguel farms. The efficiency was estimated using the DEAP. Two models are available: considering whether or not subsidies as output. The Model I showed that 7 (7.69%) farms are efficient. The level of technical efficiency is 0.312, which means, it can be possible to reduce up to 31.2% of expenditures in consumption without penalizing production. The technical efficiency of 68.8% in Model I decrease to 63.7 % in Model II, in this study case, 5 (5.49%) farms are efficient. This study characterizes the structure of the farms, presents the DEA and the most relevant work in this area, and discussion of the results. Finally, there are the concluding remarks and bibliography.