cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Partially Constrained Internal Linear Combination: a method for low-noise CMB foreground mitigation
Creators: name: Abylkairov, Y. Sultan
name: Darwish, Omar
name: Hill, J. Colin
name: Sherwin, Blake D.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Internal Linear Combination (ILC) methods are some of the most widely used multi-frequency cleaning techniques employed in CMB data analysis. These methods reduce foregrounds by minimizing the total variance in the coadded map (subject to a signal-preservation constraint), although often significant foreground residuals or biases remain. A modification to the ILC method is the constrained ILC (cILC), which explicitly nulls certain foreground components; however, this foreground nulling often comes at a high price for ground-based CMB datasets, with the map noise increasing significantly on small scales. In this paper we explore a new method, the partially constrained ILC (pcILC), which allows us to optimize the tradeoff between foreground bias and variance in ILC methods. In particular, this method allows us to minimize the variance subject to an inequality constraint requiring that the constrained foregrounds are reduced by at least a fixed factor, which can be chosen based on the foreground sensitivity of the intended application. We test our method on simulated sky maps for a Simons Observatory-like experiment; we find that for cleaning thermal Sunyaev-Zel'dovich (tSZ) contamination at $\ell \in [3000,4800]$, if a small tSZ residual of 20% of the standard ILC residual can be tolerated, the variance of the CMB temperature map is reduced by at least 50% over the cILC value. We also demonstrate an application of this method to reduce noise in CMB lensing reconstruction.
Classroom as a Microcosm: Teaching Culturally Diverse Students
Creators: name: Bećirović, Senad
name: Bešlija, Damir
Publisher: name: arXiv
Year: 2021
Subjects: subject: Physics Education (physics.ed-ph)
subject: FOS: Physical sciences

description: The twenty-first century is the century of encounter of the different races, nations, cultures, religions and customs. In the twenty-first century, man is more and more exposed to various influences that leave a trace on the entire sphere of his social life, including education. Given that education systems play one of the key roles in the formation of both physically and morally healthy communities, it is of an enormous importance to analyze the phenomenon of a classroom composed of culturally diverse students.
Archambault, F. (2022). Il controllo del pallone. I cattolici, i comunisti e il calcio in Italia (1943-anni Settanta). Firenze: Le Monnier
Creators: name: Fonzo, Erminio
Publisher: name: Eracle. Journal of Sport and Social Sciences
Year: 2022

description: Il recente libro di Fabien Archambault sul “controllo del pallone” costituisce un interessante contributo allo studio della storia dello sport e, più in generale, a quello della storia sociopolitica dell’Italia della prima Repubblica.
description: Eracle. Journal of Sport and Social Sciences, Vol 5 No 1 (2022): Media, Society and Cycling Cultures
The geochemistry of Fe, Mn, Ni, Cu, Zn and As in the water column, sediments and porewaters in a seasonally anoxic lake
Creators: name: Martin, Alan
Publisher: name: University of British Columbia
Year: 2009

description: The distributions of Fe, Mn, Ni, Cu, Zn and As in the water column, interstitial waters and associated solid phases in Balmer Lake, Ontario, were determined from samples collected in July and October of 1993, and March and May of 1994, in order to assess the seasonal biogeochemical controls governing trace metal behaviour and mobility. The basin has served as a repository for tailings pond effluents since 1967, and as a result, hosts elevated levels of contaminants in the sediments and lake waters. During the ice-free periods of summer, fall and spring, the water column is characterized by fully oxygenated bottom waters and homogeneous distributions of all measured parameters. However, reducing conditions develop in deeper areas during the period of ice cover in response to the high biological demand of the organic-rich sediments coupled with restricted atmospheric exchange. Trace metal profiles collected during winter exhibit considerable lakewide variation and appear to reflect variability in the duration and extent of bottom water anoxia, and the relative influence of metal-rich lateral inputs from the tailings circuits. Solid-phase profiles indicate that the top decimetre of the sediment column has received variable contributions of both organic matter- and feldspar-rich natural detritus, and carbonate-, chlorite- and metal-rich tailings inputs. High resolution profiles of porewater NO₃⁻, Fe, Mn and SO₄²- illustrate that the sediments in Balmer Lake become anoxic within a few centimetres of the sediment-water interface during well-mixed periods. Evidence for the precipitation of a Cu-bearing sulphide phase in the lowermost winter bottom waters suggests that the sulphate redox-cline migrates above the sediment-water interface at some point during ice cover. The seasonal porewater distributions of dissolved Ni, Cu and Zn exhibit pronounced consumption profiles at depths consistent with sulphate reduction zones, suggesting they are sequestered as metal-sulphide phases. Enrichments of dissolved Ni and Zn in the surficial sediments at most sites reflect the dissolution of labile particulates at the sediment-water interface. Diffusive influxes calculated for Zn, Ni and Cu suggest that diffusion mechanisms contribute insignificantly to the accumulation rates of these metals. Arsenic is remobilized at deeper sediment depths and appears to be largely governed by the redox geochemistry of Mn. The data collectively demonstrate that trace metal mobility in the Balmer Lake water column/sediment system varies significantly over the course of the four seasons. With the exception of arsenic, however, dissolved metal fluxes indicate that the underlying contaminated sediments are providing a significant and permanent sink for dissolved metals.
Cycling Media and Collectives. Cycling Vlogs and Mobile Infrastructures
Creators: name: Bee, Julia
Publisher: name: Eracle. Journal of Sport and Social Sciences
Year: 2022

description: Not only have cycling communities produced a visual culture consisting of photography, videos, fashion, art and bikes themselves. Conversely, images and videos produce and shape cycling culture and therefore communities. Aesthetics in the digital culture thus contribute to the complex of cycling mobility. In this paper, I concentrate on cycling vlogs as part of mobile infrastructure. Cycling vlogs cultivate a “social aesthetic” (Born et al., 2017) that adapts symbols from cycling culture, hereby bringing into circulation, and thus shaping, cycling practices. Nevertheless, the interconnection of different platform media like Youtube and performance apps makes digital cycling cultures a place of data production and harvesting of different sorts.
description: Eracle. Journal of Sport and Social Sciences, Vol 5 No 1 (2022): Media, Society and Cycling Cultures
Susceptibility of quasiclassical Brownian motion in harmonic nonlinear potentials
Creators: name: Colmenares, Pedro J.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: This work sets the exact equations for the quasiclassical response function and susceptibility of a Brownian particle immersed in a bath of quantum harmonic oscillators driving by nonlinear harmonic potentials. A delta force perturbation gives rise to a response whose susceptibility is the combination of a linear term, own of the harmonic oscillator, plus a nonlinear one involving an integral \textcolor{black}{equation. It is provided a recursion method to find its solutions based on functional equations in the Banach space.} The ODE for the response function is a highly nonlinear damped non-autonomous Duffing equation for which the aforementioned method is used to get its solution.
description: 6 pages
Un estudio de los efectos de la promoción turística y el impacto mediático de la Vuelta Ciclista a España en el contexto de la región de Extremadura
Creators: name: Blanco Gregory, Rocío
name: Porro Nieto, María
Publisher: name: Eracle. Journal of Sport and Social Sciences
Year: 2022

description: This article focuses on sports tourism in the context of a cycling event such as the Vuelta Ciclista a España, an event that has been growing gradually over time, becoming part of the professional calendar. This cycling competition takes place over a period of twenty-one days, in which selected and invited teams take part.


It is usually held at the end of August or the beginning of September, thus closing the three major cycling tours that lead the men’s World Tour category, which usually begin in May with the Giro d’Italia and continue in July with the Tour de France. 


This research analyzes some of the stages of the 2013 route that make up this great Vuelta in order to find out the social and tourist impact that they caused to the different localities through which they travelled and stayed overnight. It also aims to examine the profile of the tourist who travels in the form of sports tourism in order to enjoy the cycling races in situ and, in turn, to be close to their idols, as this sport is one of the few in which there is such proximity between the athletes and the public attending the event.
description: Eracle. Journal of Sport and Social Sciences, Vol 5 No 1 (2022): Media, Society and Cycling Cultures
Entanglement, avoided crossings and quantum chaos in an Ising model with a tilted magnetic field
Creators: name: Karthik, J.
name: Sharma, Auditya
name: Lakshminarayan, Arul
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: Other Condensed Matter (cond-mat.other)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: We study a one-dimensional Ising model with a magnetic field and show that tilting the field induces a transition to quantum chaos. We explore the stationary states of this Hamiltonian to show the intimate connection between entanglement and avoided crossings. In general entanglement gets exchanged between the states undergoing an avoided crossing with an overall enhancement of multipartite entanglement at the closest point of approach, simultaneously accompanied by diminishing two-body entanglement as measured by concurrence. We find that both for stationary as well as nonstationary states, nonintegrability leads to a destruction of two-body correlations and distributes entanglement more globally.
description: Corrections in two figure captions and one new reference. To appear in Phys. Rev. A
String Memories ... openly retold
Creators: name: Aldi, Alice
name: Bianchi, Massimo
name: Firrotta, Maurizio
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We identify string corrections to the EM memory effect. Though largely negligible in the low-energy limit, the effect become relevant in high-energy collisions and in extreme events. We illustrate our findings in a simple unoriented bosonic string model. Thanks to the coherent effect of the infinite tower of open string resonances, the corrections are non-perturbative in $α'$, modulated in retarded time and slowly decaying even at large distances from the source. Remarkably compact expressions obtain for special choices of the kinematics in tree-level 4-point amplitudes. We discuss further corrections occurring at higher-points and the exponential damping resulting from broadening and shifting of the massive poles due to loops. Finally we estimate the range of the parameters and masses for detectability in semi-realistic (Type I) contexts and propose a rationale for this string memory effect.
description: 16 pages, 5 figures
Shadows and Twisted Variables
Creators: name: Baulieu, Laurent
name: Bossard, Guillaume
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We explain how a new type of fields called shadows and the use of twisted variables allow for a better description of Yang-Mills supersymmetric theories. (Based on lectures given in Cargese, June 2006.)
description: Cargese Jun 2006
Digital representation and quantification of discrete dislocation networks
Creators: name: Robertson, Andreas E.
name: Kalidindi, Surya R.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Dislocation networks and their evolution are known to control the mechanical properties of metal samples. However, the lack of computationally efficient and statistically rigorous descriptors for such defect systems has hindered the development and adoption of rational protocols for the optimal design of these material systems. This study presents a framework for the rigorous statistical quantification and low dimensional representation of dislocation networks using the formalism of 2-point spatial correlations (also called 2-point statistics) along with Principle Component Analysis (PCA). The usefulness of this basic framework for comparing and observing dislocation networks is exemplified and discussed with suitable examples.
description: Submitted to JOM
Detecting filaments in the ultra-high energy cosmic ray distribution
Creators: name: Harari, Diego
name: Mollerach, Silvia
name: Roulet, Esteban
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We propose and test new statistical tools to study the distribution of cosmic rays based on the use of the Minimal Spanning Tree. The method described is particularly sensitive to filamentary structures, as those expected to arise from strong sources of charged cosmic rays which get deflected by intervening magnetic fields. We also test the method with data available from the AGASA and SUGAR surface detector arrays.
description: minor changes, matching the published version in Astroparticle Physics
The photophoretic sweeping of dust in transient protoplanetary disks
Creators: name: Krauss, O.
name: Wurm, G.
name: Moussis, O.
name: Petit, J. -M.
name: Horner, J.
name: Alibert, Y.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Protoplanetary disks start their lives with a dust free inner region where the temperatures are higher than the sublimation temperature of solids. As the star illuminates the innermost particles, which are immersed in gas at the sublimation edge, these particles are subject to a photophoretic force. We examine the motion of dust particles at the inner edge of protoplanetary disks due to photophoretic drag. We find that, in a laminar disk, photophoretic drag increases the size of the inner hole after accretion onto the central body has become subdued. This region within the hole becomes an optically transparent zone containing gas and large dusty particles (>>10 cm), but devoid of, or strongly depleted in, smaller dust aggregates. Photophoresis can clear the inner disk of dust out to 10 AU in less than 1 Myr. At late times, the edge reaches a stable equilibrium between inward drift and photophoretic outward drift, at a distance of some tens of AU. Eventually, the edge will move inwards again as the disk disperses, shifting the equilibrium position back from about 40 AU to below 30 AU in 1-2 Myr in the disk model. In a turbulent disk, diffusion can delay the clearing of a disk by photophoresis. Smaller and/or age-independent holes of radii of a few AU are also possible outcomes of turbulent diffusion counteracting photophoresis. This outward and then inward moving edge marks a region of high dust concentration. This density enhancement, and the efficient transport of particles from close to the star to large distances away, can explain features of comets such as high measured ratios of crystalline to amorphous silicates, and has a large number of other applications.
description: 11 pages, 6 figures
Connected components of the compactification of representation spaces of surface groups
Creators: name: Wolff, Maxime
Publisher: name: arXiv
Year: 2008
Subjects: subject: Geometric Topology (math.GT)
subject: Group Theory (math.GR)
subject: FOS: Mathematics

description: The Thurston compactification of Teichmuller spaces has been generalized to many different representation spaces by J. Morgan, P. Shalen, M. Bestvina, F. Paulin, A. Parreau and others. In the simplest case of representations of fundamental groups of closed hyperbolic surfaces in PSL(2,R), we prove that this compactification is very degenerated: the nice behaviour of the Thurston compactification of the Teichmuller space contrasts with wild phenomena happening on the boundary of the other connected components of these representation spaces. We prove that it is more natural to consider a refinement of this compactification, which remembers the orientation of the hyperbolic plane. The ideal points of this compactification are fat R-trees, i.e., R-trees equipped with a planar structure.
description: 75 pages, 11 figures
Estimative for the size of the compactification radius of a one extra dimension Universe
Creators: name: Pascoal, F.
name: Oliveira, L. F. A.
name: Rosa, F. S. S.
name: Farina, C.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this work, we use the Casimir effect to probe the existence of one extra dimension. We begin by evaluating the Casimir pressure between two plates in a $M^4\times S^1$ manifold, and then use an appropriate statistical analysis in order to compare the theoretical expression with a recent experimental data and set bounds for the compactification radius.
Quantum Simulation of the Bosonic Creutz Ladder with a Parametric Cavity
Creators: name: Hung, Jimmy S. C.
name: Busnaina, J. H.
name: Chang, C. W. Sandbo
name: Vadiraj, A. M.
name: Nsanzineza, I.
name: Solano, E.
name: Alaeian, H.
name: Rico, E.
name: Wilson, C. M.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: There has been a growing interest in realizing quantum simulators for physical systems where perturbative methods are ineffective. The scalability and flexibility of circuit quantum electrodynamics (cQED) make it a promising platform to implement various types of simulators, including lattice models of strongly-coupled field theories. Here, we use a multimode superconducting parametric cavity as a hardware-efficient analog quantum simulator, realizing a lattice in synthetic dimensions with complex hopping interactions. The coupling graph, \textit{i.e.} the realized model, can be programmed \textit{in situ}. The complex-valued hopping interaction further allows us to simulate, for instance, gauge potentials and topological models. As a demonstration, we simulate a plaquette of the bosonic Creutz ladder. We characterize the lattice with scattering measurements, reconstructing the experimental Hamiltonian and observing emerging topological features. This platform can be easily extended to larger lattices and different models involving other interactions.
description: 10 pages, 3 figures
A catalogue of orientable 3-manifolds triangulated by 30 coloured tetrahedra
Creators: name: Casali, M. R.
name: Cristofori, P.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Geometric Topology (math.GT)
subject: FOS: Mathematics
subject: 57Q15, 57M15, 57N10

description: The present paper follows the computational approach to 3-manifold classification via edge-coloured graphs, already performed by several authors with respect to orientable 3-manifolds up to 28 coloured tetrahedra, non-orientable 3-manifolds up to 26 coloured tetrahedra, genus two 3-manifolds up to 34 coloured tetrahedra: in fact, by automatic generation and analysis of suitable edge-coloured graphs, called crystallizations, we obtain a catalogue of all orientable 3-manifolds admitting coloured triangulations with 30 tetrahedra. These manifolds are unambiguously identified via JSJ decompositions and fibering structures. It is worth noting that, in the present work, a suitable use of elementary combinatorial moves yields an automatic partition of the elements of the generated crystallization catalogue into equivalence classes, which are proved to be in one-to one correspondence with the homeomorphism classes of the represented manifolds.
description: 24 pages, 7 figures
Electrocardiogram Heartbeat Classification Using Convolutional Neural Networks for the Detection of Cardiac Arrhythmia
Creators: name: Khan, Mohammad Mahmudur Rahman
name: Siddique, Md. Abu Bakr
name: Sakib, Shadman
name: Aziz, Anas
name: Tanzeem, Abyaz Kader
name: Hossain, Ziad
Publisher: name: arXiv
Year: 2020
Subjects: subject: Medical Physics (physics.med-ph)
subject: Signal Processing (eess.SP)
subject: FOS: Physical sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: The classification of the electrocardiogram (ECG) signal has a vital impact on identifying heart-related diseases. This can ensure the premature finding of heart disease and the proper selection of the patient's customized treatment. However, the detection of arrhythmia is a challenging task to perform manually. This justifies the necessity of a technique for automatic detection of abnormal heart signals. Therefore, our work is based on the classification of five classes of ECG arrhythmic signals from Physionet's MIT-BIH Arrhythmia Dataset. Artificial Neural Networks (ANN) have demonstrated significant success in ECG signal classification. Our proposed model is a Convolutional Neural Network (CNN) customized to categorize the ECG signals. Our result testifies that the planned CNN model can successfully categorize arrhythmia with an overall accuracy of 95.2%. The average precision and recall of the proposed model are 95.2% and 95.4%, respectively. This model can effectively be used to detect irregularities of heart rhythm at an early stage.
description: 4th International conference on I-SMAC (IoT in Social, Mobile, Analytics and Cloud) (I-SMAC 2020), IEEE, 7-9 October 2020, TamilNadu, INDIA
Exploiting Locally Imposed Anisotropies in (Ga,Mn)As: a Non-volatile Memory Device
Creators: name: Pappert, K.
name: Hümpfner, S.
name: Gould, C.
name: Wenisch, J.
name: Brunner, K.
name: Schmidt, G.
name: Molenkamp, L. W.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Progress in (Ga,Mn)As lithography has recently allowed us to realize structures where unique magnetic anisotropy properties can be imposed locally in various regions of a given device. We make use of this technology to fabricate a device in which we study transport through a constriction separating two regions whose magnetization direction differs by 90 degrees. We find that the resistance of the constriction depends on the flow of the magnetic field lines in the constriction region and demonstrate that such a structure constitutes a non-volatile memory device.
Cycling as a food-delivery rider. Or the difficult negotiation among speed, safety and accuracy
Creators: name: Bonifacio, Francesco
Publisher: name: Eracle. Journal of Sport and Social Sciences
Year: 2022

description: Platform-based food-delivery riders have been primarily analyzed in relation to organisational or regulatory issues, thus overlooking the actual practices that involve them materially, bodily and cognitively. In particular, less attention has been given to a central aspect of this occupation: cycling. By understanding food-delivery work as a social practice (Hui et al., 2016), this paper aims to show that:


1) the organisational and material conditions in which food-delivery work takes place frame the emergence of a specific mode of urban cycling, which concerns the difficult negotiation of speed, safety and accuracy.


2) in order to meet the requirements of practice, riders draw on a set of norms and practical skills by which they define the correct way to accomplish this work.


The research draws on a seven-months Milan-based observant participation (Wacquant, 2015) – during which the author worked as a Glovo part-time rider – supplemented by 21 in-depth interviews with workers.
description: Eracle. Journal of Sport and Social Sciences, Vol 5 No 1 (2022): Media, Society and Cycling Cultures
Dynamics and bifurcations on the normally hyperbolic invariant manifold of a periodically driven system with rank-1 saddle
Creators: name: Kuchelmeister, Manuel
name: Reiff, Johannes
name: Main, Jörg
name: Hernandez, Rigoberto
Publisher: name: arXiv
Year: 2020
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: In chemical reactions, trajectories typically turn from reactants to products when crossing a dividing surface close to the normally hyperbolic invariant manifold (NHIM) given by the intersection of the stable and unstable manifolds of a rank-1 saddle. Trajectories started exactly on the NHIM in principle never leave this manifold when propagated forward or backward in time. This still holds for driven systems when the NHIM itself becomes time dependent. We investigate the dynamics on the NHIM for a periodically driven model system with two degrees of freedom by numerically stabilizing the motion. Using Poincaré surfaces of section we demonstrate the occurrence of structural changes of the dynamics, \emph{viz.}, bifurcations of periodic transition state (TS) trajectories when changing the amplitude and frequency of the external driving. In particular, periodic TS trajectories with the same period as the external driving but significantly different parameters---such as mean energy---compared to the ordinary TS trajectory can be created in a saddle-node bifurcation.
description: 11 pages, 6 figures
Αναγνωστική κατανόηση και αναπαραγωγή αφηγηματικού γραπτού λόγου παιδιών με δυσκολίες μάθησης:
Creators: name: Τσίγγος, Ελευθέριος Σπυρίδωνος
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: Δυσκολίες μάθησης
Αναγνωστική κατανόηση
Αφηγηματικές δυσκολίες
Learning difficulties
Reading comprehension
Narrative difficulties

description: Το μεγαλύτερο μέρος των παιδιών με δυσκολίες μάθησης αντιμετωπίζει αναγνωστικές αδυναμίες, οι οποίες σύμφωνα με πολλούς ερευνητές αποτελούν το κυριότερο παράγοντα της σχολικής αποτυχίας. Η λειτουργία της ανάγνωσης αποτελεί μια σύνθετη διεργασία, υπεισέρχεται στη διδασκαλία όλων των σχολικών μαθημάτων και αποτελεί προϋπόθεση για την κατανόηση και έκφραση του γραπτού λόγου. Ένα μεγάλο ποσοστό των παιδιών με αναγνωστικές δυσκολίες αντιμετωπίζει προβλήματα κατανόησης και παραγωγής γραπτού λόγου, τα οποία επιδρούν αρνητικά στη μαθησιακή τους ικανότητα και συμβάλουν στη χαμηλή σχολική επίδοση. Η παρούσα εργασία έχει στόχο να διερευνήσει τα προβλήματα αναγνωστικής κατανόησης και γραπτής αναπαραγωγής αφηγηματικών κειμένων μαθητών Ε΄ & ΣΤ΄ Δημοτικού με μαθησιακές δυσκολίες, καθώς και παιδιών με γενικευμένη υποεπίδοση, που σύμφωνα με τα κριτήρια οριοθέτησης δεν εμπίπτουν στην κατηγορία των μαθησιακών δυσκολιών. Από τα ευρήματα της έρευνας διαπιστώνουμε ότι η ομάδα των μαθητών με μαθησιακές δυσκολίες αντιμετωπίζει επιμέρους δυσκολίες σε επίπεδο κατανόησης και γραπτής αναπαραγωγής αφηγηματικού κειμένου, ενώ η ομάδα των μαθητών με υποεπίδοση αντιμετωπίζει πιο γενικευμένες αναγνωστικές δυσκολίες και σοβαρότερα προβλήματα κατανόησης και αναπαραγωγής αφηγηματικού κειμένου σε σχέση με την πρώτη.
description: Most of the children with learning difficulties have reading disabilities which, according to many researchers, constitute the main reason for school failure. Reading is definitely a complicated process which forms part of teaching (any school subject) and it is considered to be a prerequisite for the comprehension and production of written discourse. A large amount of children with reading difficulties have problems concerning the reproduction or the comprehension of written discourse. These problems affect negatively children’s learning ability, leading to a low school performance. The goal of this paper is to examine the problems concerning reading comprehension and written reproduction of narrative texts, focusing on fifth- and sixth- grade, primary school children with learning disabilities, as well as on children with a generalized low performance who, according to diagnostic criteria, do not belong to the same category with those having learning disabilities. The results of the research show that the group of children with learning disabilities faces additional difficulties concerning the comprehension and the written reproduction of narrative texts whereas the group of children with a low performance faces more generalized, reading difficulties and more serious problems concerning the comprehension and the written reproduction of narrative texts.
Black holes and core expansion in massive star clusters
Creators: name: Mackey, A. D.
name: Wilkinson, M. I.
name: Davies, M. B.
name: Gilmore, G. F.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present the results from realistic N-body modelling of massive star clusters in the Magellanic Clouds. We have computed eight simulations with N ~ 10^5 particles; six of these were evolved for at least a Hubble time. The aim of this modelling is to examine the possibility of large-scale core expansion in massive star clusters and search for a viable dynamical origin for the radius-age trend observed for such objects in the Magellanic Clouds. We identify two physical processes which can lead to significant and prolonged cluster core expansion: mass-loss due to rapid stellar evolution in a primordially mass segregated cluster, and heating due to a retained population of stellar-mass black holes. These two processes operate over different time-scales - the former occurs only at early times and cannot drive core expansion for longer than a few hundred Myr, while the latter typically does not begin until several hundred Myr have passed but can result in core expansion lasting for many Gyr. We investigate the behaviour of these expansion mechanisms in clusters with varying degrees of primordial mass segregation and in clusters with varying black hole retention fractions. In combination, the two processes can lead to a wide variety of evolutionary paths on the radius-age plane, which fully cover the observed cluster distribution and hence define a dynamical origin for the radius-age trend in the Magellanic Clouds. We discuss the implications of core expansion for various aspects of globular cluster research, as well as the possibility of observationally inferring the presence of a population of stellar-mass black holes in a cluster.
description: Accepted for publication in MNRAS
To the ravines! Encountering, exploring, and expanding Toronto’s mountain bike trails during and beyond the Covid-19 pandemic
Creators: name: Tiessen, Matthew
Publisher: name: Eracle. Journal of Sport and Social Sciences
Year: 2022

description: This paper is about how Toronto’s urban mountain bike trails offered an escape from the reductive worldview I’m calling the “Covid Cosmology”. I describe how in the face of Covid-19 lockdowns, Toronto’s mountain bike trails offer cyclists salutary experiences that run counter to those offered by the centralized authorities intent on managing the pandemic. These salutary experiences include: 1) Freedom; 2) Expansion, Optimization & Intensification, 3) Flow, 4) Boundaries, Exclusions, and Creating Community, and 5) Risk. Informed by non-representational ethnographic approaches (Vannini, 2015), I examine the use and expansion of Toronto’s urban mountain bike trails by venturing into the wilds that exist above, below, and alongside urban environments during the pandemic’s painful periods of lockdowns. The objective: to speculate about the ways human potential can be expanded with the help of urban wilderness and in response to totalizing ontologies designed to define life itself using a narrow, binaristic worldview.
description: Eracle. Journal of Sport and Social Sciences, Vol 5 No 1 (2022): Media, Society and Cycling Cultures
Magnetic excitations and their anisotropy in YBCO: slave-boson mean-field analysis of bilayer t-J model
Creators: name: Yamase, Hiroyuki
name: Metzner, Walter
Publisher: name: arXiv
Year: 2006
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We perform a comprehensive analysis of the dynamical magnetic susceptibility χ(q,ω) in the slave-boson mean-field scheme of the bilayer t-J model. In the d-wave pairing state, the strongest magnetic spectral weight appears at q=Q=(pi,pi) and ω=ω_{Q}^{res}, and spreads into a diamond-shaped shell around Q in q space for ω ω_{Q}^{res} strong signals of Imχ(q,ω) tracing an upward dispersion are found and interpreted as an overdamped collective mode near ω_{Q}^{res}. In the normal state, Imχ(q,ω) has a broad peak at q=Q. That is, the IC and DIC signals appear only in the d-wave pairing state. We also study effects of a small orthorhombic anisotropy, which is intrinsic in untwinned YBCO crystals. Because of electron-electron correlations favoring d-wave shaped Fermi surface deformations (dFSD), we expect an enhanced anisotropy of magnetic excitation spectra. This effect is particularly pronounced for low δand at relatively high temperature. The present theory provides a rather detailed microscopic explanation of the most salient properties of magnetic excitations observed in YBCO.
description: 50 pages, 20 figures
Thermodynamics and evaporation of the noncommutative black hole
Creators: name: Myung, Yun Soo
name: Kim, Yong-Wan
name: Park, Young-Jai
Publisher: name: arXiv
Year: 2006
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We investigate the thermodynamics of the noncommutative black hole whose static picture is similar to that of the nonsingular black hole known as the de Sitter-Schwarzschild black hole. It turns out that the final remnant of extremal black hole is a thermodynamically stable object. We describe the evaporation process of this black hole by using the noncommutativity-corrected Vaidya metric. It is found that there exists a close relationship between thermodynamic approach and evaporation process.
description: 16 pages, 6 figures, added references, to appear in JHEP
Quantum state reconstruction with imperfect rotations on an inhomogeneously broadened ensemble of qubits
Creators: name: Tordrup, Karl
name: Mølmer, Klaus
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We present a method for performing quantum state reconstruction on qubits and qubit registers in the presence of decoherence and inhomogeneous broadening. The method assumes only rudimentary single qubit rotations as well as knowledge of decoherence and loss mechanisms. We show that full state reconstruction is possible even in the case where single qubit rotations may only be performed imperfectly. Furthermore we show that for ensemble quantum computing proposals, quantum state reconstruction is possible even if the ensemble experiences inhomogeneous broadening and if only imperfect qubit manipulations are available during state preparation and reconstruction.
description: 6 pages, 5 figures
Trouble in Watopia: Negotiating Community Wellbeing and Cheating in Zwift eSports Cycling
Creators: name: Thorne, Sarah
Publisher: name: Eracle. Journal of Sport and Social Sciences
Year: 2022

description: This article examines Zwift (2015), a massively multiplayer online game that uses an indoor trainer to connect one’s bicycle to a virtual world. Using the trainer’s various sensors, the game translates speed, cadence, and power data into the movement of the user’s in-game avatar. One of Zwift’s most popular features are its competitive races that allow cyclists to compete against others at recreational and elite levels. As in any multiplayer game, cheating has become a concern on the platform. Much of the discussion around cheating has focused on “weight-doping,” whereby an individual manipulates their weight to gain an advantage over other racers. While virtual “weigh-ins” have been implemented to curb cheating at the elite level, these have proven to be controversial and potentially harmful to racers. Drawing on studies of cheating in games, this article examines the mechanics of Zwift that give rise to “weight-doping” to understand the risks and potential harm of its current anti-cheat measures and their relation to self-tracking and gamification.
description: Eracle. Journal of Sport and Social Sciences, Vol 5 No 1 (2022): Media, Society and Cycling Cultures
Investigating the dependence of proton T₁ relaxation on pore size, pore fluid salinity, and pore fluid pH in water-wet sand packs
Creators: name: Kanters, William Andrew
Publisher: name: University of British Columbia
Year: 2009

description: The dependence of the proton nuclear magnetic resonance parameter, T₁ on surface wettability, grain size, and pore fluid chemistry was investigated using laboratory prepared silica sand packs. A pulsed proton NMR spectrometer, with a proton Larmour frequency of 90 MHz, was used to obtain the T₁ relaxation data. Pore fluid T₁ data were found to be dependent on the surface wettability of the sand packs. An observed difference in T₁ of approximately 1 second was obtained between 100% water-wet and 100% oil-wet sand packs, when the pH of the pore fluid was neutral. This difference in T₁ between the water-wet and oil-wet samples when saturated with distilled water, was observed for a range of different pore sizes. T₁ relaxation time was found to depend on sand pack grain size in both the water-wet and oil-wet samples. This indicated the presence of surface relaxation in the samples. Calculated surface relaxivities produced average values of 1.2 x 10-₃ cm/s and 2.6 x lO-₄ cm/s for the water-wet and the oil-wet samples respectively. Pore fluid chemistry was found to affect T₁ relaxation measurements in water-wet and oil-wet sand packs. Experimental results indicated that although T₁ was unaffected by pore fluid salinity it was dependent on the pore fluid pH. Results showed that as pore fluid acidity increased, T₁ relaxation times decreased in both the water-wet and the oil-wet sand packs. This enhanced relaxation at lower pH's was attributed to increased pore fluid relaxation at the grain surfaces.
Pairs of commuting nilpotent operators with one-dimensional intersection of kernels and matrices commuting with a Weyr matrix
Creators: name: Bondarenko, Vitalij M.
name: Futorny, Vyacheslav
name: Petravchuk, Anatolii P.
name: Sergeichuk, Vladimir V.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Representation Theory (math.RT)
subject: FOS: Mathematics
subject: 15A21, 15A27, 16G60

description: I.M. Gelfand and V.A. Ponomarev (1969) proved that the problem of classifying pairs (A,B) of commuting nilpotent operators on a vector space contains the problem of classifying an arbitrary t-tuple of linear operators. Moreover, it contains the problem of classifying representations of an arbitrary quiver, and so it is considered as hopeless. We give a simple normal form of the matrices of (A,B) if the intersection of kernels of A and B is one-dimensional. We prove that this form is canonical if the Jordan matrix of A is a direct sum of Jordan blocks of the same size and the field is of zero characteristic.
Ο θεσμός του Σχολικού Επαγγελματικού Προσανατολισμού (Σ.Ε.Π.) στη δευτεροβάθμια εκπαίδευση: διερευνώντας τις απόψεις των Συμβούλων Σ.Ε.Π.
Creators: name: Δερμεντζοπούλου, Βασιλεία Γεωργίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: Σχολικός επαγγελματικός προσανατολισμός (ΣΕΠ)
Σύμβουλοι ΣΕΠ
ΚΕ.ΣΥ.Π (Κέντρα Συμβουλευτικής και Προσανατολισμού)
School and vocational guidance
School counsellors
Secondary education

description: Στόχος της παρούσας έρευνας ήταν να διερευνήσει σε βάθος τις απόψεις των Συμβούλων ΣΕΠ, οι οποίοι εργάζονταν στα πλαίσια του θεσμού και συγκεκριμένα στα ΚΕ.ΣΥ.Π., τα οποία, ωστόσο, καταργήθηκαν πρόσφατα βάσει μεταρρύθμισης του Υπουργείου Παιδείας, Δια Βίου Μάθησης και Θρησκευμάτων. Οι συμμετέχοντες ήταν εκπαιδευτικοί της δευτεροβάθμιας εκπαίδευσης, που εργάζονταν ως Σύμβουλοι ΣΕΠ σε ΚΕ.ΣΥ.Π της Βορείου Ελλάδος και μέσω ημι-δομημένων συνεντεύξεων ανέδειξαν την εικόνα, που είχαν διαμορφώσει για το θεσμό τα τελευταία χρόνια της λειτουργίας του. Επιλέχθηκε η ερμηνευτική φαινομενολογική ανάλυση, ως κατάλληλη μεθοδολογία για τη διεξαγωγή του ερευνητικού σχεδίου. Από την ανάλυση των αποτελεσμάτων προέκυψαν τρία βασικά θέματα, γύρω από τα οποία οργανώθηκαν οι απόψεις των συμμετεχόντων. Πρώτον, οι σύμβουλοι αναφέρθηκαν στο θεσμό σε προσωπικό επίπεδο, όπως για παράδειγμα για τους λόγους, που τους ώθησαν, ώστε να ασχοληθούν επαγγελματικά με τον ΣΕΠ. Επίσης, στο λόγο τους διατυπώθηκαν απόψεις, που αφορούσαν σε θεσμικό επίπεδο, όπως είναι η ανάγκη για επιμόρφωση των συμβούλων και στήριξη του θεσμού από τους υπεύθυνους φορείς, Τέλος, δεν έλλειψαν προτάσεις σε πρακτικό επίπεδο, με τους συμβούλους να αναφέρονται σε οικονομικά ζητήματα και θέματα υλικοτεχνικής υποδομής.
description: This study intended to examine deeply school and vocational counselors’ experience, who work at the relevant services, named Centers of Counseling and Guidance. These centers had recently repealed because of a reformation, that the Ministry of Education has begun. The participants in this study were teachers of the secondary education, who have been working in the centers, mentioned above, in the wider region of North Greece. Through semi-structured interviews, the participants analyzed their experience about the institution of school and vocational guidance. Interpretative phenomenological analysis (IPA) was chosen, as the appropriate methodology, according to the demands of the research plan. The analysis of the results has revealed three basics themes through the participants’ speech. First, the counselors mentioned their opinions on a personal level, such as the reasons, that motivated them to work officially with the institution of school and vocational guidance. In addition, they formed opinions relevant to an institutional level, such as demands about counselors’ training and the support, that should have been given to the institution by the relevant communities. Finally, counselors’ interviews revealed opinions about a practical level, such as financial difficulties and logistics obstacles.
Hydrostatic approximation of the 2D MHD system in a thin strip with a small analytic data
Creators: name: Aarach, Nacer
Publisher: name: arXiv
Year: 2020
Subjects: subject: Analysis of PDEs (math.AP)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: In this paper, we study the global well-posedness of the two dimensional rescaled anisotropic MHD system and also to the hydrostatic MHD with no slip boundary condition in a strip, for small initial data, which are analytic in the horizontal variable. We also justify the limit of the MHD system (when $ε\to 0$ where $ε$ denotes the height of the initial strip) is given by a couple of a Prandtl like system for the velocity and a magnetic field equation when the initial data are small and analytic.
Early-type stars in the young open cluster IC1805. II. The probably single stars HD15570 and HD15629, and the massive binary/triple system HD15558
Creators: name: De Becker, M.
name: Rauw, G.
name: Manfroid, J.
name: Eenens, P.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Aims: We address the issue of the multiplicity of the three brightest early-type stars of the young open cluster IC1805, namely HD15570, HD15629 and HD15558. Methods: For the three stars, we measured the radial velocity by fitting Gaussian curves to line profiles in the optical domain. In the case of the massive binary HD15558, we also used a spectral disentangling method to separate the spectra of the primary and of the secondary in order to derive the radial velocities of the two components. These measurements were used to compute orbital solutions for HD15558. Results: For HD15570 and HD15629, the radial velocities do not present any significant trend attributable to a binary motion on time scales of a few days, nor from one year to the next. In the case of HD15558 we obtained an improved SB1 orbital solution with a period of about 442 days, and we report for the first time on the detection of the spectral signature of its secondary star. We derive spectral types O5.5III(f) and O7V for the primary and the secondary of HD15558. We tentatively compute a first SB2 orbital solution although the radial velocities from the secondary star should be considered with caution. The mass ratio is rather high, i.e. about 3, and leads to very extreme minimum masses, in particular for the primary object. Minimum masses of the order of 150 \pm 50 and 50 \pm 15 M_\odot are found respectively for the primary and the secondary. Conclusions: We propose that HD15558 could be a triple system. This scenario could help to reconcile the very large minimum mass derived for the primary object with its spectral type. In addition, considering new and previously published results, we find that the binary frequency among O-stars in IC1805 has a lower limit of 20%, and that previously published values (80%) are probably overestimated.
description: 12 pages, including 6 figures (+ 4 pages of online material), accepted for publication by A&A