cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Image Cropping on Twitter: Fairness Metrics, their Limitations, and the Importance of Representation, Design, and Agency
Creators: name: Yee, Kyra
name: Tantipongpipat, Uthaipon
name: Mishra, Shubhanshu
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computers and Society (cs.CY)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Human-Computer Interaction (cs.HC)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Twitter uses machine learning to crop images, where crops are centered around the part predicted to be the most salient. In fall 2020, Twitter users raised concerns that the automated image cropping system on Twitter favored light-skinned over dark-skinned individuals, as well as concerns that the system favored cropping woman's bodies instead of their heads. In order to address these concerns, we conduct an extensive analysis using formalized group fairness metrics. We find systematic disparities in cropping and identify contributing factors, including the fact that the cropping based on the single most salient point can amplify the disparities because of an effect we term argmax bias. However, we demonstrate that formalized fairness metrics and quantitative analysis on their own are insufficient for capturing the risk of representational harm in automatic cropping. We suggest the removal of saliency-based cropping in favor of a solution that better preserves user agency. For developing a new solution that sufficiently address concerns related to representational harm, our critique motivates a combination of quantitative and qualitative methods that include human-centered design.
description: Accepted to CSCW 2021
Three-dimensional Monte Carlo simulations of the quantum linear Boltzmann equation
Creators: name: Breuer, Heinz-Peter
name: Vacchini, Bassano
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Recently the general form of a translation-covariant quantum Boltzmann equation has been derived which describes the dynamics of a tracer particle in a quantum gas. We develop a stochastic wave function algorithm that enables full three-dimensional Monte Carlo simulations of this equation. The simulation method is used to study the approach to equilibrium for various scattering cross sections and to determine dynamical deviations from Gaussian statistics through an investigation of higher-order cumulants. Moreover, we examine the loss of coherence of superpositions of momentum eigenstates and determine the corresponding decoherence time scales to quantify the transition from quantum to classical behavior of the state of the test particle.
description: 11 pages, revtex, 11 figures
Reproducibility in Social Sciences and Statistics: Context, Concerns, and Concrete Measures
Creators: name: Vilhuber, Lars
Publisher: name: Zenodo
Year: 2019
Subjects: reproducibility
replicability
data availability statements
journal policies

description: Replicability is at the core of the scientific enterprise. In the past 30 years, recurring concerns about the extent of replicability (or lack thereof) of the research in various disciplines have surfaced, including in economics.

In this talk, I describe the context in which the current discussion in the social science is occurring: what are the definitions of replicability and reproducibility, what is failing, and to what extent. In particular, I discuss the concerns in economics: to what extent is this a problem in economics, what are the approaches that are being considered, and what are the possible broader implications of those approaches. Finally, I discuss the concrete measures that are being implemented under my guidance at the American Economic Association, and that are being discussed in the broader economics community.

The solutions to these problems will change the way research will be taught and conducted, in economics in particular, and in the social sciences more broadly. The implications affect undergraduate and graduate teaching, research infrastructure, and habits.

Presented at Western Economic Association's 94TH ANNUAL CONFERENCE on 2019-06-29.
description: The opinions expressed in this talk are solely the authors, and do not represent the views of the U.S. Census Bureau, the American Economic Association, or any of the funding agencies.
On the approximation of functions by tanh neural networks
Creators: name: De Ryck, Tim
name: Lanthaler, Samuel
name: Mishra, Siddhartha
Publisher: name: arXiv
Year: 2021
Subjects: subject: Numerical Analysis (math.NA)
subject: Machine Learning (cs.LG)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: We derive bounds on the error, in high-order Sobolev norms, incurred in the approximation of Sobolev-regular as well as analytic functions by neural networks with the hyperbolic tangent activation function. These bounds provide explicit estimates on the approximation error with respect to the size of the neural networks. We show that tanh neural networks with only two hidden layers suffice to approximate functions at comparable or better rates than much deeper ReLU neural networks.
Orbit-based deformation procedure for two-field models
Creators: name: Afonso, V. I.
name: Bazeia, D.
name: Leon, M. A. Gonzalez
name: Losano, L.
name: Guilarte, J. Mateos
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We present a method for generating new deformed solutions starting from systems of two real scalar fields for which defect solutions and orbits are known. The procedure generalizes the approach introduced in a previous work [Phys. Rev. D 66, 101701(R) (2002)], in which it is shown how to construct new models altogether with its defect solutions, in terms of the original model and solutions. As an illustration, we work out an explicit example in detail.
description: 15 pages, 14 figures; version to appear in PRD
On how good DFT exchange-correlation functionals are for H bonds in small water clusters: Benchmarks approaching the complete basis set limit
Creators: name: Santra, Biswajit
name: Michaelides, Angelos
name: Scheffler, Matthias
Publisher: name: arXiv
Year: 2007
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The ability of several density-functional theory (DFT) exchange-correlation functionals to describe hydrogen bonds in small water clusters (dimer to pentamer) in their global minimum energy structures is evaluated with reference to second order Moeller Plesset perturbation theory (MP2). Errors from basis set incompleteness have been minimized in both the MP2 reference data and the DFT calculations, thus enabling a consistent systematic evaluation of the true performance of the tested functionals. Among all the functionals considered, the hybrid X3LYP and PBE0 functionals offer the best performance and among the non-hybrid GGA functionals mPWLYP and PBE1W perform the best. The popular BLYP and B3LYP functionals consistently underbind and PBE and PW91 display rather variable performance with cluster size.
description: 9 pages including 4 figures; related publications can be found at http://www.fhi-berlin.mpg.de/th/th.html
Trapping and Cooling a mirror to its quantum mechanical ground state
Creators: name: Bhattacharya, M.
name: Meystre, P.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We propose a technique aimed at cooling a harmonically oscillating mirror to its quantum mechanical ground state starting from room temperature. Our method, which involves the two-sided irradiation of the vibrating mirror inside an optical cavity, combines several advantages over the two-mirror arrangements being used currently. For comparable parameters the three-mirror configuration provides a stiffer trap for the oscillating mirror. Furthermore it prevents bistability from limiting the use of higher laser powers for mirror trapping, and also partially does so for mirror cooling. Lastly, it improves the isolation of the mirror from classical noise so that its dynamics are perturbed mostly by the vacuum fluctuations of the optical fields. These improvements are expected to bring the task of achieving ground state occupation for the mirror closer to completion.
description: 5 pages, 1 figure
Access Control
Creators: name: Beznosov, Konstantin
Publisher: name: Zenodo
Year: 2005
Subjects: access control

description: Learning objectives:  Comprehend the principles behind access control mechanisms used in today\\\\\\\'s:  * operating systems, * middleware, * virtual machines. Overview: In this module, the principles behind access control mechanisms and policies employed in todays operating systems, middleware, and virtual machines are studied. Two key principles are at the basis of all protection mechanisms:  * the Trusted Computing Base (TCB) * the Reference Monitor. Generic representations of access control policies follow: * Lampson Access Matrix, and its optimized forms, * Access Control Lists (ACLs) * Capabilities. The focus shifts to the main types of access control policies: * owner-based Discretionary Access Control (DAC), * lattice-based Mandatory Access Control (MAC), * Chinese Wall model, * Clark-Wilson model, and * role-based access control (RBAC).
Generalising Multilingual Concept-to-Text NLG with Language Agnostic Delexicalisation
Creators: name: Zhou, Giulio
name: Lampouras, Gerasimos
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computation and Language (cs.CL)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Concept-to-text Natural Language Generation is the task of expressing an input meaning representation in natural language. Previous approaches in this task have been able to generalise to rare or unseen instances by relying on a delexicalisation of the input. However, this often requires that the input appears verbatim in the output text. This poses challenges in multilingual settings, where the task expands to generate the output text in multiple languages given the same input. In this paper, we explore the application of multilingual models in concept-to-text and propose Language Agnostic Delexicalisation, a novel delexicalisation method that uses multilingual pretrained embeddings, and employs a character-level post-editing model to inflect words in their correct form during relexicalisation. Our experiments across five datasets and five languages show that multilingual models outperform monolingual models in concept-to-text and that our framework outperforms previous approaches, especially for low resource languages.
description: ACL-IJCNLP 2021 camera ready version
Dynamics of Quantum Hall Interfaces
Creators: name: Li, Qi
name: Ma, Ken K. W.
name: Wang, Ruojun
name: Hu, Zi-Xiang
name: Wang, Hao
name: Yang, Kun
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: A quantum Hall (QH) interface is different from an ordinary QH edge, as the latter has its location determined by the confining potential, while the former can be unpinned and behave like a free string. In this paper, we demonstrate this difference by studying three different interfaces formed by (i) the Laughlin state and the vacuum, (ii) the Pfaffian state and the vacuum, and (iii) the Pfaffian and the anti-Pfaffian states. We find that string-like interfaces propagating freely in the QH system lead to very different dynamical properties from edges. This qualitative difference gives rise to fascinating new physics and suggests a new direction in future research on QH physics. We also discuss briefly possible analogies between QH interfaces and concepts in string theory.
description: Published version
Phase-resolved hard X-ray emission of the high-mass binary LS 5039: a spectral hardening above 50 keV detected with INTEGRAL
Creators: name: Falanga, M.
name: Bykov, A. M.
name: Li, Z.
name: Krassilchtchikov, A. M.
name: Petrov, A. E.
name: Bozzo, E.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Aims: LS 5039 is an enigmatic high-mass gamma-ray binary which hosts a powerful O6.5V companion, but the nature of the compact object is still to be established using multi-wavelength observations. Methods: We analyzed phase-resolved multi-instrument spectra of nonthermal emission from LS 5039 in order to produce reliable spectral models, which can be further employed to select between various scenarios and theoretical models of the binary. Results: The combined phase-resolved hard X-ray and MeV-range gamma-ray spectra obtained with XMM-Newton, Suzaku, NuSTAR, INTEGRAL, and COMPTEL indicate a meaningful spectral hardening above 50~keV. The spectral break observed in both major phases of the binary may indicate the presence of a hardening in the spectrum of accelerated leptons which could originate from the interaction of wind from the O6.5V companion star with the relativistic outflow from a yet unidentified compact object.
description: Accepted for publication in A&A 13 July 2021, 7 pages, 7 figures, 3 tables
Access Control Architectures: COM+ vs. EJB
Creators: name: Beznosov, Konstantin
Publisher: name: Zenodo
Year: 2005
Subjects: EJB
COM+
distributed systems security
access control

description: This tutorial provides an overview of access control mechanisms in two most popular commercial middleware technologies, COM+ and EJB. Three main aspects of the mechanisms are explained: a) how enforcement of the access control policies is done, b) the main elements of each technology access control model, and c) the types of policies supported. The technologies are compared, in respect to access control, against each other. Their advantages and disadvantages are discussed.
Αλγόριθμοι ανίχνευσης έκτοπων παρατηρήσεων (Outliers) στην ανθεκτική στατιστική (Robust) εκτίμηση συνδιακύμανσης και παλινδρόμησης:
Creators: name: Χατζηνάκος, Χρήστος Ν.
Publisher: name: Aristotle University of Thessaloniki
Year: 2014
Subjects: Ανθεκτική Στατιστική
Ανθεκτική Εκτίμηση Θέσης
Ανθεκτική Εκτίμηση Πίνακα Συνδιακύμανσης
Ανθεκτική Παλινδρόμηση
Robust Statistic
Robust Location Estimate
Robust Estimation of Covariance Matrix
Robust Regression

description: Σκοπός της παρούσας διατριβής ήταν ανάπτυξη νέων ανθεκτικών εκτιμητών-αλγόριθμων. Παρουσιάστηκαν νέοι αλγόριθμοι για την εκτίμηση θέσης και παλινδρόμησης. Επιπλέον, παρουσιάστηκαν μέθοδοι υπολογιστικά εφικτοί και ανθεκτικοί για την εκτίμηση θέσης, συνδιακύμανσης καθώς και για την ανθεκτική εκτίμηση γραμμικής παλινδρόμησης, χρησιμοποιώντας τεχνικές και μοντέλα μαθηματικού προγραμματισμού. Οι νέοι εκτιμητές της έρευνας είναι νέας γενιάς εκτιμητές, διότι έχουν υψηλό σημείο κατάρρευσης, είναι αποδοτικοί, πολύ ανθεκτικοί και μπορούν να αντιμετωπίσουν όλων των ειδών τα έκτοπα
description: The aim of the present thesis was the development of robust estimators-algorithms. We presented new algorithms for location estimate and regression estimate. Furthermore, we developed methods computationally efficient and robust for location-covariance estimation and robust linear regression using special mathematical programming models. The new estimators of the research are new generation estimators, because the have high breakdown point, they are efficient, very robust and the address with every type of outliers
Measurement of e^+e^- to pi^+pi^-J/psi Cross Section via Initial State Radiation at Belle
Creators: name: Belle Collaboration
name: Yuan, C. Z.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The cross section for e^+e^- to pi^+pi^-J/psi between 3.8 and 5.5 GeV/c^2 is measured using a 548 fb^{-1} data sample collected on or near the Upsilon(4S) resonance with the Belle detector at KEKB. A peak near 4.25 GeV/c^2, corresponding to the so called Y(4260), is observed. In addition, there is another cluster of events at around 4.05 GeV/c^2. A fit using two interfering Breit-Wigner shapes describes the data better than one that uses only the Y(4260), especially for the lower mass side of the 4.25 GeV enhancement.
description: 11 pages, 5 figures, 2 tables; version to appear in PRL
Intrinsic Sensitivity Limits for Multiparameter Quantum Metrology
Creators: name: Goldberg, Aaron Z.
name: Sánchez-Soto, Luis L.
name: Ferretti, Hugo
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The quantum Cramér-Rao bound is a cornerstone of modern quantum metrology, as it provides the ultimate precision in parameter estimation. In the multiparameter scenario, this bound becomes a matrix inequality, which can be cast to a scalar form with a properly chosen weight matrix. Multiparameter estimation thus elicits tradeoffs in the precision with which each parameter can be estimated. We show that, if the information is encoded in a unitary transformation, we can naturally choose the weight matrix as the metric tensor linked to the geometry of the underlying algebra $\mathfrak{su}(n)$, with applications in numerous fields. This ensures an intrinsic bound that is independent of the choice of parametrization.
description: 6 pages; comments welcome!
The effects of acute and chronic hypercapnia upon ventilation and acid-base status in the pekin duck
Creators: name: Dodd, Graham Alan Andrew
Publisher: name: University of British Columbia
Year: 2010

description: In this study, awake Pekin ducks (Anas platyrhynchos) were exposed to periods of acute and chronic hypercapnia (0.05 F₁CO₂). Measurements were made of ventilation and acid-base status in both adult and juvenile male ducks as well as in adult female ducks. All Pekin ducks, regardless of age or sex, responded acutely to inspired CO₂ with a marked hypercapnic-hyperpnea. Inhalation of CO₂ resulted in a significant increase in arterial CO₂ tension (PaCO₂) and decrease in arterial pH (pHa). The increase (3 times (x)) in minute ventilation (V[sub E]), while primarily a function of an increase (2x) in tidal volume (V[sub T]), also involved an increase (1.5x) in breathing frequency (f[sub b]). The chronic responses of ducks to inspired CO₂, however, did differ depending upon the sex of the animal. In male ducks, the initial increase observed in V[sub E]during the first 20 minutes was reduced by 50% after 300 minutes. This partial recovery in V[sub E]resulted entirely from the complete return of f[sub b] to its control levels as V[sub T]remained both elevated and constant throughout the period of hypercapnia. In addition, the male ducks also demonstrated a significant recovery (50%) in pHa, a change that was paradoxical to the concomitant increase measured in PaCO₂. While a change in strong ion difference (SID) was not detected, the accompanying rise in calculated arterial [HCO₃⁺] suggested that metabolic compensatory processes must have alleviated the initial respiratory acidosis. The rate of metabolic compensation seen in the ducks of this study exceeds that reported for any other air-breathing vertebrate. Female ducks, on the other hand, maintained the initial increase in V[sub E]and decrease in pHa throughout the period of CO₂ exposure. The reasons for this remain unclear although it is speculated that the metabolic demands of eggshell formation may have limited the capacity of these birds to mobilize further HCO₃⁻ stores. Differences in the changes which occurred in f[sub b], V[sub T], pH and P[sub CO₂] in male and female ducks during chronic CO₂ exposure strongly suggest that the changes in f[sub b] were a singular function of changes in pHa ([H⁺]) while changes in VT were primarily a function of changes in PaCO₂. Denervation of peripheral chemoreceptors appeared to have little effect upon the overall ventilatory responses to either acute or chronic hypercapnia, suggesting that central chemoreceptors must have been predominantly responsible for the ventilatory responses observed during this study.
Testing General Metric Theories of Gravity with Bursting Neutron Stars
Creators: name: Psaltis, Dimitrios
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: I show that several observable properties of bursting neutron stars in metric theories of gravity can be calculated using only conservation laws, Killing symmetries, and the Einstein equivalence principle, without requiring the validity of the general relativistic field equations. I calculate, in particular, the gravitational redshift of a surface atomic line, the touchdown luminosity of a radius-expansion burst, which is believed to be equal to the Eddington critical luminosity, and the apparent surface area of a neutron star as measured during the cooling tails of bursts. I show that, for a general metric theory of gravity, the apparent surface area of a neutron star depends on the coordinate radius of the stellar surface and on its gravitational redshift in the exact same way as in general relativity. On the other hand, the Eddington critical luminosity depends also on an additional parameter that measures the degree to which the general relativistic field equations are satisfied. These results can be used in conjunction with current and future high-energy observations of bursting neutron stars to test general relativity in the strong-field regime.
description: 7 pages, Physical Review D, in press; corrected expression for Eddington limit
Stationary and non-stationary fluid flow of a Bose-Einstein condensate through a penetrable barrier
Creators: name: Engels, P.
name: Atherton, C.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We experimentally study the fluid flow induced by a broad, penetrable barrier moving through an elongated dilute gaseous Bose-Einstein condensate. The barrier is created by a laser beam swept through the condensate, and the resulting dipole potential can be either attractive or repulsive. We examine both cases and find regimes of stable and unstable fluid flow: At slow speeds of the barrier, the fluid flow is stationary due to the superfluidity of the condensate. At intermediate speeds, we observe a non-stationary regime in which the condensate gets filled with dark solitons. At faster speeds, soliton formation completely ceases and a remarkable absence of excitation in the condensate is seen again.
description: 4 pages, 4 figures
Development of Tracking Detectors with industrially produced GEM Foils
Creators: name: Simon, F.
name: Azmoun, B.
name: Becker, U.
name: Burns, L.
name: Crary, D.
name: Kearney, K.
name: Keeler, G.
name: Majka, R.
name: Paton, K.
name: Saini, G.
name: Smirnov, N.
name: Surrow, B.
name: Woody, C.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: The planned tracking upgrade of the STAR experiment at RHIC includes a large-area GEM tracker used to determine the charge sign of electrons and positrons produced from W+(-) decays. For such a large-scale project commercial availability of GEM foils is necessary. We report first results obtained with a triple GEM detector using GEM foils produced by Tech-Etch Inc. of Plymouth, MA, USA. Measurements of gain uniformity, long-term stability as well as measurements of the energy resolution for X-Rays are compared to results obtained with an identical detector using GEM foils produced at CERN. A quality assurance procedure based on optical tests using an automated high-resolution scanner has been established, allowing a study of the correlation of the observed behavior of the detector and the geometrical properties of the GEM foils. Detectors based on Tech-Etch and CERN produced foils both show good uniformity of the gain over the active area and stable gain after an initial charge-up period, making them well suited for precision tracking applications.
description: 6 pages, 14 figures, published in IEEE Transactions on Nuclear Science, v2 updated text and figures
Hopf algebras of dimension pq, II
Creators: name: Ng, Siu-Hung
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Algebra (math.QA)
subject: Rings and Algebras (math.RA)
subject: FOS: Mathematics
subject: 16W30

description: Let H be a Hopf algebra of dimension pq over an algebraically closed field of characteristic zero, where p, q are odd primes with p < q < 4p+12. We prove that H is semisimple and thus isomorphic to a group algebra, or the dual of a group algebra.
description: 14pp, Latex
Dissecting nonthermal emission in the complex multiple-merger galaxy cluster Abell 2744: Radio and X-ray analysis
Creators: name: Rajpurohit, K.
name: Vazza, F.
name: van Weeren, R. J.
name: Hoeft, M.
name: Brienza, M.
name: Bonnassieux, E.
name: Riseley, C. J.
name: Brunetti, G.
name: Bonafede, A.
name: Brüggen, M.
name: Formann, W. R.
name: Rajpurohit, A. S.
name: Röttgering, H. J. A.
name: Drabent, A.
name: Domínguez-Fernández, P.
name: Wittor, D.
name: Andrade-Santos, F.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We present the first deep low frequency radio observations of the massive and highly disturbed galaxy cluster Abell 2744 using the upgraded Giant Metrewave Radio Telescope (uGMRT). The cluster is experiencing a very complex multiple merger and hosts a giant halo and four radio relics. The uGMRT observations, together with existing VLA and Chandra observations, allow us to study the complexity of the physical mechanisms active in this system. Our new images reveal that the central halo emission is more extended toward low frequencies. We find that the integrated spectrum of the halo follows a power-law between 150 MHz and 3 GHz, while its subregions show significantly different spectra, also featuring high frequency spectral steepening. The halo also shows local regions in which the spectral index is significantly different from the average value. Our results highlight that an overall power-law spectrum, as observed in many radio halos, may also arise from the superposition of different subcomponents. The comparison of the radio surface brightness and spectral index with the X-ray brightness and temperature reveals for the first time different trends, indicating that the halo consists of two main components. All four relics in this system follow a power-law radio spectrum, compatible with shocks with Mach numbers in the range $3.0-4.5$. All relics are also highly polarized from 1-4 GHz and show low Faraday dispersion measures, suggesting that they are located in the outermost regions of the cluster. The complexity in the distribution and properties of nonthermal components in Abell 2744 supports a multiple merger scenario, as also highlighted by previous X-ray and lensing studies. Our unique results demonstrate the importance of sensitive and high-resolution, multi-frequency radio observations for understanding the interplay between the thermal and non-thermal components of the ICM.
description: 24 pages, 19 figures, accepted for publication in A&A
A polarizable ion model for the structure of molten AgI
Creators: name: Bitrián, Vicente
name: Trullàs, Joaquim
Publisher: name: arXiv
Year: 2007
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: The results are reported of the molecular dynamics simulations of the coherent static structure factor of molten AgI at 923 K using a polarizable ion model. This model is based on a rigid ion potential, to which the many body interactions due to the anions induced polarization are added. The calculated structure factor is in better agreement with recent neutron diffraction data than that obtained by using simple rigid ion pair potentials. The Voronoi-Delaunay method has been applied to study the relationship between voids in the spatial distribution of cations and the prepeak of the structure factor.
description: 12 pages, 4 figures
The Topological Theory of the Milnor Invariant $\barμ(1,2,3)$
Creators: name: Leal, Lorenzo
name: Pineda, Jesus
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study a topological Abelian gauge theory that generalizes the Abelian Chern-Simons one, and that leads in a natural way to the Milnor's link invariant $\barμ(1,2,3)$ when the classical action on-shell is calculated.
description: 4 pages; corrected equation
A genetic analysis of Region 31 on Chromosome 2 of Drosophila melanogaster
Creators: name: Brock, Jo-Ann Karen
Publisher: name: University of British Columbia
Year: 2010

description: Genes that are subject to position-effect variegation (PEV) are located at newly formed euchromatic/heterochromatic junctions of chromosomal rearrangements. Variegated expression of these genes is believed to result from structural changes in their normal chromatin conformation. Several genetic modifiers of PEV have been identified which can suppress variegated phenotypes. The wild-type products of these genes are thought to be involved in formation or maintenance of chromatin structure, either as structural components, or as assembly or modifying factors. Several dominant suppressors of variegation (Su(var)s) have been localized to the left arm of chromosome 2 (region 31) of Drosophila melanoqaster. A number of intergenic effects are noted when suppressor mutations of this region, mapping to separate loci, are combined in trans. These include male lethality, female sterility and at least two visible phenotypic anomalies: changes in eye colour (possibly resulting from the altered expression of the heterochromatic light gene) and abnormal wing morphology. These effects may occur through additive or synergistic interactions of mutant Su(var) products which alter the integrity of heterochromatin to such an extent that expression of heterochromatic genes is affected. This hypothesis is supported by the fact that altering the heterochromatic content of the cell affects the expression of these abnormal phenotypes. Deletion or addition of a Y chromosome (which presumably acts as a sink for normal Su(var) products) is able to, respectively, ameliorate or exacerbate the intergenic effects. Most of the suppressor genes investigated in this study are hemizygous lethal or female sterile. An additional forty-two EMS-induced mutants were generated in a screen to isolate mutations of essential genes (including suppressor loci) in region 31. These new mutants were characterized genetically. While none of them are dominant suppressors of position-effect variegation, several alleles of at least one Su(var) locus were recovered. This result supports the suggestion that a special event (antimorphic mutation) is necessary to elicit a suppressing phenotype from the Su(var) loci located in region 31.
Η σύγχρονη αναβίωση του μοναχισμού στην Κοπτική Εκκλησία το παράδειγμα των Μονών του Wadi Al-Natrun
Creators: name: Andraws, George Michil
Publisher: name: Aristotle University of Thessaloniki
Year: 2014
Subjects: Κοπτική Εκκλησία
Μοναχισμός
Σύγχρονη Αναβίωση
Άγιοι
Coptic Church
Monasticism
Modern Revival
Saints

description: Η εργασία μας, που αναφέρεται στην περίοδο από το δεύτερο μισό του εικοστού αιώνα μέχρι και σήμερα, περιλαμβάνει την εισαγωγή και πέντε κεφάλαια. Το πρώτο κεφάλαιο μιλάει για την αναχώρηση κάποιου από τον κόσμο προς το μοναστήρι, για τη συγκεκριμένη απόφαση, γιατί επιλέγει ένα συγκεκριμένο μοναστήρι και γιατί τα μοναστήρια δεν δέχονται το σύνολο αυτών που θέλουν να μονάσουν, ενώ ακόμα εξετάζουμε την περίοδο της δοκιμασίας, αλλά και την έννοια της αποταγής του κόσμου. Παρακολουθούμε, στο δεύτερο κεφάλαιο, τη ζωή του μοναχού στο μοναστήρι, τα έργα και τους ρόλους που αναλαμβάνουν οι μοναχοί, τις μορφές μοναχισμού, ενώ επίσης μιλάμε και για το γυναικείο μοναχισμό. Στο τρίτο κεφάλαιο, εξετάζουμε τη σχέση Εκκλησίας και μοναχισμού, το πώς δηλαδή προσφέρει ο μοναχισμός στις διάφορες πλευρές του έργου της Εκκλησίας και στη ζωή των πιστών. Στο τέταρτο κεφάλαιο, αναφερόμαστε σε παραδείγματα σύγχρονων αγίων μοναχών. Στο τελευταίο κεφάλαιο, κάνουμε σύγκριση του αρχαίου με το σύγχρονο μοναχισμό σε διάφορα στοιχεία, όπως στη λατρεία, την εργασία, τις επισκέψεις κτλ.
description: Our work, which refers to the period from the second half of the twentieth century until today, consists of an introduction and five chapters. The first chapter speaks about the departure of someone from the world to the monastery, for this specific decision, why he chooses a specific monastery and why the monasteries do not accept all those who want to be monks, while still examining the probationary period, but also the concept of leaving the world. We follow, in the second chapter, the life of a monk in the monastery, the work and roles undertaken by the monks, the forms of monasticism, while also referring to female monasticism. In the third chapter, we examine the relationship between the Church and monasticism, what monasticism offers in the various aspects of the work of the Church and in the lives of the believers. In the fourth chapter, we refer to examples of contemporary monastic saints. In the last chapter, we compare the ancient to the modern monasticism in various items such as worship, work, visits, etc.
Realignment separability criterion assisted with filtration for detecting continuous-variable entanglement
Creators: name: Hertz, Anaelle
name: Arnhem, Matthieu
name: Asadian, Ali
name: Cerf, Nicolas J.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We introduce a weak form of the realignment separability criterion which is particularly suited to detect continuous-variable entanglement and is physically implementable (it requires linear optics transformations and homodyne detection). Moreover, we define a family of states, called Schmidt-symmetric states, for which the weak realignment criterion reduces to the original formulation of the realignment criterion, making it even more valuable as it is easily computable especially in higher dimensions. Then, we focus in particular on Gaussian states and introduce a filtration procedure based on noiseless amplification or attenuation, which enhances the entanglement detection sensitivity. In some specific examples, it does even better than the original realignment criterion.
description: Minor corrections in v2 to match the published version of the paper
Particle multiplicities in Lead-Lead collisions at the LHC from non-linear evolution with running coupling
Creators: name: Albacete, Javier L.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We present predictions for the pseudo-rapidity density of charged particles produced in central Pb-Pb collisions at the LHC. Particle production in such collisions is calculated in the framework of k_t-factorization. The nuclear unintegrated gluon distributions at LHC energies are determined from numerical solutions of the Balitsky-Kovchegov equation including recently calculated running coupling corrections. The initial conditions for the evolution are fixed by fitting RHIC data at collision energies \sqrt{s}}=130 and 200 GeV per nucleon. We obtain dN^{Pb-Pb}_{ch}/dη(\sqrt{s}=5.5 TeV, η=0)\approx 1290÷1480.
description: Version accepted for publication by Phys. Rev. Lett. Typos corrected, one figure removed and references updated
An Automated and Comprehensive Framework for IoT Botnet Detection and Analysis (IoT-BDA)
Creators: name: Trajanovski, Tolijan
name: Zhang, Ning
Publisher: name: arXiv
Year: 2021
Subjects: subject: Cryptography and Security (cs.CR)
subject: FOS: Computer and information sciences

description: The proliferation of insecure Internet-connected devices gave rise to the IoT botnets which can grow very large rapidly and may perform high-impact cyber-attacks. The related studies for tackling IoT botnets are concerned with either capturing or analyzing IoT botnet samples, using honeypots and sandboxes, respectively. The lack of integration between the two implies that the samples captured by the honeypots must be manually submitted for analysis in sandboxes, introducing a delay during which a botnet may change its operation. Furthermore, the effectiveness of the proposed sandboxes is limited by the potential use of anti-analysis techniques and the inability to identify features for effective detection and identification of IoT botnets. In this paper, we propose and evaluate a novel framework, the IoT-BDA framework, for automated capturing, analysis, identification, and reporting of IoT botnets. The framework consists of honeypots integrated with a novel sandbox that supports a wider range of hardware and software configurations, and can identify indicators of compromise and attack, along with anti-analysis, persistence, and anti-forensics techniques. These features can make botnet detection and analysis, and infection remedy more effective. The framework reports the findings to a blacklist and abuse service to facilitate botnet suspension. The paper also describes the discovered anti-honeypot techniques and the measures applied to reduce the risk of honeypot detection. Over the period of seven months, the framework captured, analyzed, and reported 4077 unique IoT botnet samples. The analysis results show that some IoT botnets used anti-analysis, persistence, and anti-forensics techniques typically seen in traditional botnets.
description: This article has been accepted for publication in IEEE Access Journal
Near-Infrared and X-ray Observations of the Enigmatic G70.7+1.2
Creators: name: Cameron, P. B.
name: Kulkarni, S. R.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present high resolution imaging of the puzzling radio and optical nebula G70.7+1.2 with the Keck Observatory's laser guide star adaptive optics (LGS-AO) system and the Chandra X-ray Observatory. The archival X-ray observations show a hard (Gamma ~ 1.8), low luminosity (L_X ~ 4 x 10^31 ergs/s) point source at the center of the nebula. Follow-up LGS-AO near-infrared imaging of the Chandra error circle reveals a relatively bright (K' ~ 14 magnitude) counterpart. Both its color and brightness are consistent with a heavily obscured B-star or possibly a late-G/early-K giant. The most plausible explanation is that this newly discovered X-ray source is a non-accreting B-star/pulsar binary powering the radio and optical nebula. If so, the luminous Be-star discussed in the literature seemingly embedded in the nebula is not the dominant force responsible for shaping G70.7+1.2. Thus, we suggest that G70.7+1.2 is the result of two unrelated objects (a B-star X-ray binary and a Be star) interacting with a dense molecular cloud. With this explanation we believe we have solved the mystery of the origin of G70.7+1.2.
description: 13 pages, 4 figures. Submitted to ApJL, referee's comments incorporated
Ιατροδικαστική διερεύνηση των εγκλημάτων κατά ζωής στη Βόρεια Ελλάδα από το 1944 μέχρι το 2008: επιδημιολογική μελέτη
Creators: name: Τζήκας, Αντώνιος Γ.
Publisher: name: Aristotle University of Thessaloniki
Year: 2014
Subjects: Ανθρωποκτονίες
Βόρεια Ελλάδα
Περίοδος 1944-2008
Εξέλιξη ανθρωποκτονιών
Homicides
Northern Greece
1944-2008 period
Homicide development

description: Στην παρούσα διατριβή μελετήθηκαν οι ανθρωποκτονίες που σημειώθηκαν στην ευρύτερη περιοχή της βόρειας Ελλάδας, την περίοδο 1944-2008. Υλικό της διατριβής αποτέλεσε η βάση δεδομένων του Εργαστηρίου Ιατροδικαστικής και Τοξικολογίας του Αριστοτελείου Πανεπιστημίου Θεσσαλονίκης. Οι παράμετροι οι οποίες μελετήθηκαν αφορούσαν στο φύλο των θυμάτων, στην ηλικία τους, στο είδος του όπλου που χρησιμοποιήθηκε για την ανθρωποκτονία, στην ανατομική περιοχή που επλήγη και στην εποχή του έτους κατά την οποία τελέστηκε το έγκλημα. Συγκεκριμένα μετά από μελέτη άνω των 25000 ιατροδικαστικών εκθέσεων προέκυψαν 1160 ανθρωποκτονίες, από τις οποίες οι μισές περίπου (551) αφορούσαν στην περίοδο 1944-1949. Οι υπόλοιπες 609 ανθρωποκτονίες ήταν διαμοιρασμένες στις δεκαετίες που ακολούθησαν με αρκετά κανονική διασπορά. Εξαίρεση αποτέλεσαν οι τελευτές δύο δεκαετίες (1990-1999 και 2000 2008) κατά τις οποίες σημειώθηκε μεγάλη αύξηση των ανθρωποκτονιών. Η αύξηση αυτή αποδόθηκε στην εισροή “ανθρωποκτόνου αλλοδαπού πληθυσμού” στην Ελλάδα με αποτέλεσμα την περαιτέρω αύξηση του είδη υπάρχοντος ποσοστού ανθρωποκτονιών. Εκτός από τα στατιστικά δεδομένα που προέκυψαν από την παρούσα διατριβή σημαντικό ήταν και το γεγονός ότι τα εγκλήματα κατά ζωής δεν αποτελούν ένα σταθερό φαινόμενο σε μια κοινωνία, αλλά αντιθέτως επηρεάζονται και εξελίσσονται με την πάροδο του χρόνου και την πρόοδο της τεχνολογίας και της κοινωνίας όπως όλες οι λοιπές ανθρώπινες δραστηριότητες.
description: At the present dissertation the homicides in the broad region of northern Greece during the period 1944-2008 were studied. The data base of the Department of Forensic Medicine and Toxicology, Aristotle University of Thessaloniki was the material for this study. The parameters that were studied had to do with the sex and age of the victims, the type of the weapon that was used, the anatomical region which was fatally injured and the season of the year on which the homicide was committed. On close examination of more than 25000 autopsy reports, a number of 1160 homicides were found. About half of them (551) were committed during the period 1944-1949. The rest 609 homicides were normally distributed through the years with only slight fluctuations. The exception was only the last two decades (1990-1999 and 2000-2008), where a significant increase of homicides was observed. This rise was the result of a large number of “foreign-imported criminal population” which had also as a result the increase of the already existing homicides. The importance of this dissertation, apart the statistical analysis, concerns the fact that crime and in particular in our case homicide, was not a stable factor but on the contrary it was affected by time and technology development, as well as by social conditions and human activities.
Γλώσσα, τέχνη και σιωπή: έρευνα με αφετηρία τις σκέψεις των L. Wittgenstein, F. Kafka και S. Zweig
Creators: name: Κοροσιάδης, Μουράτης Γ.
Publisher: name: Aristotle University of Thessaloniki
Year: 2014
Subjects: Εντροπία
Σιωπή
Ζωγραφική
Γλωσσική δηλητηρίαση
Entropie
Schweigen
Malerei
Sprachvergiftung

description: Με αφετηρία τους ιμπρεσιονιστές αρχίζει η αλλαγή στη ζωγραφική που μας παραπέμπει σ’ ένα κόσμο του οποίου οι βεβαιότητες δεν ισχύουν πια και ο οποίος παρασύρει σε εσωτερική αποσταθεροποίηση το ανθρώπινο υποκείμενο. Η τέχνη δεν αναπαριστά αλλά αποκαλύπτει και καταγγέλλει. Η λύση των λογικών δεσμών στα έργα των Van Gogh, de Chirico, Magritte, των Γερμανών εξπρεσιονιστών, του σουρεαλισμού, του ντανταϊσμού και του κυβισμού προχωρούν αντίθετα προς την επιστημονική σαφήνεια, τεκμηρίωση και αιτιοκρατία. Στο Tractatus διακηρύσσεται ότι η γλώσσα δεν έχει πρόσβαση στον κόσμο των αξιών. Τον χώρο του άρρητου αναλαμβάνει να τον εκφράσει η τέχνη. Η τέχνη η οποία οδηγείται στην εντροπική σιωπή καθώς συγκρούεται με την χρηστική-εξουσιαστική μορφή της γλώσσας. Σε πολιτικό και κοινωνικό επίπεδο, πέρα από την προσωπική τραγωδία, θα υπάρξει επιβολή της ενιαίας σκέψης, ομογενοποίηση και απάλειψη κάθε διαφορετικότητας. Στα έργα των F. Kafka και S. Zweig παρατηρούμε την πορεία πτώσης των ηρώων που προκύπτει μέσα από τα εντροπικά φαινόμενα που αναπτύσσονται τόσο στην γλώσσα όσο και στην κοινωνική πρακτική.
description: Ist es, vielleicht, die "bisher medizinisch unbekannte Schachvergiftung" an der Dr. B., in der Schachnovelle von S. Zweig, gelitten hat, in der Wirklichkeit eine Sprachvergiftung? Und der Satz "Verzeihen Sie mir die Blamage - es war das letztemal, das ich mich im Schach versucht habe", war es auch sein letzter Versuch in der Sprache? Ist damit gemeint, dass es nur ihm keine andere Möglichkeit gab außer dem Schweigen? In einer Sprache die, von der Rhetorik und den Lügen jedes trojanischen Krieges, vergiftet ist und uns mit Vergiftung droht, bleibt uns eine andere Wahl - Ausweg als der Bereich des Schweigens? Und der entropische Druck, den eine derartige Sprache auf den einzelnen Menschen ausübt, hat nur persönliche oder auch gesellschaftliche und politische Konsequenzen? Die Werke der Malerei des 19.ten und 20.sten Jahrhunderts stellen nicht nur die Welt dar, sie klagen sie an. Die metaphysische Malerei von de Chirico, die Werke von Magritte, Van Gogh und Delvaux versuchen einen Ausweg zum Traum und verteidigen das menschliche Wesen. Der Deutsche Expressionismus und der Dadaismus klagen den Krieg, die Rhetorik der Lügen und die Ideologie der Maschinen an.Im Tractatus wurde erklärt, dass die Sprache keinen Zugang auf die Welt der Werte hat. Also uns bleibt nur die Kunst übrig. Bleibt aber die Kunst von den entropischen Phänomenen ungetastet oder wird sie auch zum einheitlichen Denken und zur Globalisierung des Mittelalters geführt, wie die Romane von F. Kafka beweisen?
Nonlinear dynamics of flux compactification
Creators: name: Corman, Maxence
name: East, William E.
name: Johnson, Matthew C.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study the nonlinear evolution of unstable flux compactifications, applying numerical relativity techniques to solve the Einstein equations in $D$ dimensions coupled to a $q$-form field and positive cosmological constant. We show that initially homogeneous flux compactifications are unstable to dynamically forming warped compactifications. In some cases, we find that the warping process can serve as a toy-model of slow-roll inflation, while in other instances, we find solutions that eventually evolve to a singular state. Analogous to dynamical black hole horizons, we use the geometric properties of marginally trapped surfaces to characterize the lower dimensional vacua in the inhomogeneous and dynamical settings we consider. We find that lower-dimensional vacua with a lower expansion rate are dynamically favoured, and in some cases find spacetimes that undergo a period of accelerated expansion followed by contraction.
description: 37 pages, 12 figures, changed to match JHEP version
High-order harmonic generation from diatomic molecules with large internuclear distance: The effect of two-center interference
Creators: name: Chen, Y. J.
name: Liu, J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: In the present paper, we investigate the high-order harmonic generation (HHG) from diatomic molecules with large internuclear distance using a strong field approximation (SFA) model. We find that the hump and dip structure emerges in the plateau region of the harmonic spectrum, and the location of this striking structure is sensitive to the laser intensity. Our model analysis reveals that two-center interference as well as the interference between different recombination electron trajectories are responsible for the unusual enhanced or suppressed harmonic yield at a certain order, and these interference effects are greatly influenced by the laser parameters such as intensity.
description: 5 pages,4 figures