cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Renormalization Ambiguities and Conformal Anomaly in Metric-Scalar Backgrounds
Creators: name: Asorey, M.
name: de Berredo-Peixoto, G.
name: Shapiro, I. L.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We analyze the problem of the existing ambiguities in the conformal anomaly in theories with external scalar field in curved backgrounds. In particular, we consider the anomaly of self-interacting massive scalar field theory and of Yukawa model in the massless conformal limit. In all cases the ambiguities are related to finite renormalizations of a local non-minimal terms in the effective action. We point out the generic nature of this phenomenon and provide a general method to identify the theories where such an ambiguity can arise.
description: RevTeX, 10 pages, no figures. Small comment and two references added. Accepted for publication in Physical Review D
654 GHz Continuum and C18O (6-5) Observations of G240.31+0.07 with the Submillimeter Array
Creators: name: Chen, Huei-Ru
name: Su, Yu-Nung
name: Liu, Sheng-Yuan
name: Hunter, Todd R.
name: Wilner, David J.
name: Zhang, Qizhou
name: Lim, Jeremy
name: Ho, Paul T. P.
name: Ohashi, Nagayoshi
name: Hirano, Naomi
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report a dual-band observation at 223 and 654 GHz (460 micron) toward an ultracompact (UC) HII region, G240.31+0.07, with the Submillimeter Array. With a beam size of 1"5 X 0"8, the dust continuum emission is resolved into two clumps, with clump A coincident well with an H2O maser and the UC HII region. The newly discovered clump, B, about 1"3 (~8.3 X 10^3 AU) to the southwest of clump A, is also associated with H2O masers and may be a more recent star-forming site. The continuum flux densities imply an opacity spectral index of β= 1.5 +- 0.3, suggestive of a value lower than the canonical 2.0 found in the interstellar medium and in cold, massive cores. The presence of hot (~100 K) molecular gas is derived by the brightness ratio of two H2CO lines in the 223 GHz band. A radial velocity difference of 2.5 +- 0.4 km/s is found between the two clumps in C18O (6-5) emission. The total (nebular and stellar) mass of roughly 58 Msun in the central region is close to, but not by far larger than, the minimum mass required for the two clumps to be gravitationally bound for binary rotation. Our continuum data do not suggest a large amount of matter associated with the H2 knots that were previously proposed to arise from a massive disk or envelope.
description: 12 pages, 2 tables, 3 figures, accepted by the Astrophysical Journal Letters
High-energy gamma-ray emission from SNR G57.2+0.8 hosting SGR J1935+2154
Creators: name: Anjos, Rita C. dos
name: Coelho, Jaziel G.
name: Pereira, Jonas P.
name: Catalani, Fernando
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In recent years some efforts have been made to identify active sources capable of accelerating particles up to $10^{15}$ eV, known as PeVatrons. Measurements of TeV ($10^{12}$ eV) gamma-rays from supernova remnants (SNRs) have shown that efficient particle acceleration can occur in SNR diffusive shocks. In this paper, we obtain the contribution to the high energy and very-high-energy gamma-ray (VHE, $E > 100$ GeV) emission due to cosmic-ray acceleration from SNR G57.2+0.8 hosting the Soft Gamma Repeater (SGR) J1935+2154 with the use of the GALPROP code. To do so, we take into account the SNR + SGR association as a single source close to the Galactic center. We propose that the above setting can provide a more comprehensive scenario for the generation of GeV-TeV gamma-rays. We also discuss the contribution from the SNR G57.2+0.8 and SGR J1935+2154 region to the diffusive TeV energy gamma-ray emission from the Galactic center.
description: 19 pages, 2 figures, 1 table. Comments are welcome
Statistics of coherent waves inside media with Lévy disorder
Creators: name: Razo-López, L. A.
name: Genack, Azriel Z.
name: Gopar, Victor A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: Structures with heavy-tailed distributions of disorder occur widely in nature. The evolution of such systems, as in foraging for food or the occurrence of earthquakes is generally analyzed in terms of an incoherent series of events. But the study of wave propagation or lasing in such systems requires the consideration of coherent scattering. We consider the distribution of wave energy inside 1D random media in which the spacing between scatterers follow a Lévy $α$-stable distribution characterized by a power-law decay with exponent $α$. We show that the averages of the intensity and logarithmic intensity are given in terms of the average of the logarithm of transmission and the depth into the sample raised to the power $α$. Mapping the depth into the sample to the number of scattering elements yields intensity statistics that are identical to those found for Anderson localization in standard random media. This allows for the separation for the impacts of disorder distribution and wave coherence in random media.
description: 6 pages, 5 figures, minor changes
Real-time implementation of adaptive control of industrial robots
Creators: name: Zhou, Yuchen
Publisher: name: University of British Columbia
Year: 2009

description: A robot working in an industrial environment has some uncertainties in its dynamics and is subject to some external disturbances. Application of adaptive control to the robot is intended to tolerate these uncertainties and disturbances by letting the robot system learn and improve its performance as it operates. Usually, adaptive control algorithms assume that the control torque can be generated as desired. Since most of industrial robots are actuated by electrical DC motors, this assumption neglects actuator dynamics. In fact, the behavior of the actuators (DC motors) is governed by a third order differential equation, and sometimes the actuator dynamics will dominate the robot dynamics. Very few experiments have been reported on the adaptive control of robots incorporating actuator dynamics. Development, stability analysis and implementation of an adaptive control scheme that incorporates actuator dynamics is the core of this thesis research. To evaluate adaptive control and to compare its performance with other control schemes through real-time implementation, a robot testbed is developed by retrofitting an industrial robot with a custom-built controller. The testbed features an open hardware architecture, high computational capacity and good software programmability. The development of the testbed is also an essential part of the thesis research. The adaptive control scheme incorporating actuator dynamics is implemented on this testbed. The effects of the actuator dynamics are studied. Experiments show that the performance of the robot, with the adaptive control scheme, is significantly improved when compensated for the actuator dynamics. The comparison between the proposed control scheme and the conven tional joint PD controller shows that application of adaptive control to an industrial robot can significantly improve the performance of the robot with minimal extra cost.
Evolutionary relations between different types of Magnetized Compact Objects
Creators: name: Lipunov, V. M.
name: Grinshpun, V.
name: Vlasenko, D.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The numerous compact sources associated with neutron stars and white dwarfs discovered in recent decades are analyzed in terms of the Gravimagnetic Rotator model (GMR paradigm - Lipunov, 1987a; Lipunov, 1992). We offer the instrument for understanding of various observed features and evolutionary relationships of neutron stars and white dwarfs. We depict in a single diagram all objects from radio pulsars and dwarf novae to ultra luminous X-ray sources and a radio pulsating white dwarf. This diagram directly demonstrates the genetic link between different types of compact sources thereby making it possible to confirm and illustrate clearly the established evolutionary connections - such as that between bulge X-ray sources and millisecond pulsars. This approach allows us to understand the evolutionary status of Ultra Luminous X-ray sources. In addition, we propose an additional evolutionary branch of the formation of Magnetars. When our work was completed, an article by Kirsten et al.2021, was published, which reports the localization of FRB 20200120 in one of the globular clusters of the galaxy M81. This shows that the accretion-induced collapse scenario of the white dwarf (Lipunov and Postnov, 1985), considered in detail in this work, is a possible genealogical branch of Magnetar production.
description: 18 pages, 4 figures, accepted in New AStronomy Review
Going Forward with the Nancy Grace Roman Space Telescope Transient Survey: Validation of Precision Forward-Modeling Photometry for Undersampled Imaging
Creators: name: Rubin, David
name: Cikota, Aleksandar
name: Aldering, Greg
name: Fruchter, Andy
name: Perlmutter, Saul
name: Sako, Masao
Publisher: name: arXiv
Year: 2021
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The Nancy Grace Roman Space Telescope (Roman) is an observatory for both wide-field observations and coronagraphy that is scheduled for launch in the mid 2020's. Part of the planned survey is a deep, cadenced field or fields that enable cosmological measurements with type Ia supernovae (SNe Ia). With a pixel scale of 0".11, the Wide Field Instrument will be undersampled, presenting a difficulty for precisely subtracting the galaxy light underneath the SNe. We use simulated data to validate the ability of a forward-model code (such codes are frequently also called "scene-modeling" codes) to perform precision supernova photometry for the Nancy Grace Roman Space Telescope SN survey. Our simulation includes over 760,000 image cutouts around SNe Ia or host galaxies (~ 10% of a full-scale survey). To have a realistic 2D distribution of underlying galaxy light, we use the VELA simulated high-resolution images of galaxies. We run each set of cutouts through our forward-modeling code which automatically measures time-dependent SN fluxes. Given our assumed inputs of a perfect model of the instrument PSFs and calibration, we find biases at the millimagnitude level from this method in four red filters (Y106, J129, H158, and F184), easily meeting the 0.5% Roman inter-filter calibration requirement for a cutting-edge measurement of cosmological parameters using SNe Ia. Simulated data in the bluer Z087 filter shows larger ~ 2--3 millimagnitude biases, also meeting this requirement, but with more room for improvement. Our forward-model code has been released on Zenodo.
description: Accepted for Publication in PASP
Confinement engineering of s-d exchange interactions in GaMnAs quantum wells
Creators: name: Stern, N. P.
name: Myers, R. C.
name: Poggio, M.
name: Gossard, A. C.
name: Awschalom, D. D.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Recent measurements of coherent electron spin dynamics reveal an antiferromagnetic s-d exchange coupling between conduction band electrons and electrons localized on Mn{2+} impurities in GaMnAs quantum wells. Here we discuss systematic measurements of the s-d exchange interaction in GaMnAs/AlGaAs quantum wells with different confinement potentials using time-resolved Kerr rotation. Extending previous investigations of the dependence of the s-d exchange, N{0}alpha, on well width, we find that its magnitude also depends on well depth. Both phenomena reduce to a general dependence on confinement energy, described by a band-mixing model of confinement-induced kinetic exchange in the conduction band.
description: 4 pages, 5 figures
A Century of Economic Policy Uncertainty Through the French-Canadian Lens
Creators: name: Ardia, David
name: Bluteau, Keven
name: Kassem, Alaa
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Economics (econ.GN)
subject: FOS: Economics and business

description: A novel token-distance-based triple approach is proposed for identifying EPU mentions in textual documents. The method is applied to a corpus of French-language news to construct a century-long historical EPU index for the Canadian province of Quebec. The relevance of the index is shown in a macroeconomic nowcasting experiment.
A Framework for the Development of Manufacturing Simulators: Towards New Generation of Simulation Systems
Creators: name: Kryssanov, V. V.
name: Abramov, V. A.
name: Hibino, H.
name: Fukuda, Y.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Computational Engineering, Finance, and Science (cs.CE)
subject: Human-Computer Interaction (cs.HC)
subject: FOS: Computer and information sciences

description: In this paper, an attempt is made to systematically discuss the development of simulation systems for manufacturing system design. General requirements on manufacturing simulators are formulated and a framework to address the requirements is suggested. Problems of information representation as an activity underlying simulation are considered. This is to form the necessary mathematical foundation for manufacturing simulations. The theoretical findings are explored through a pilot study. A conclusion about the suitability of the suggested approach to the development of simulation systems for manufacturing system design is made, and implications for future research are described.
description: 9 pages, 6 figures. Preprint completed in 1998
Ανάλυση χρηματιστηριακών δεδομένων με χρήση γραφημάτων
Creators: name: Λέσσης, Κωνσταντίνος Χαραλάμπους
Publisher: name: Aristotle University of Thessaloniki
Year: 2018
Subjects: Χρηματιστήριο Αθηνών
συντελεστής συσχέτισης Pearson
δίκτυα συσχέτισης μετοχών
Athens Stock Exchange
Pearson’s correlation coefficient
stock correlation networks

description: Σκοπός της παρούσας εργασίας είναι η μελέτη της εξέλιξης του δικτύου συσχέτισης των λογαριθμικών αποδόσεων των μετοχών των δεικτών large cap και mid cap του ελληνικού χρηματιστηρίου την περίοδο 2005-2016. Για τον υπολογισμό των συσχετίσεων των μετοχών χρησιμοποιήθηκε ο συντελεστής συσχέτισης του Pearson, ενώ η δημιουργία των δικτύων βασίστηκε στην υπόθεση ότι δύο μετοχές συνδέονται με μία ακμή αν η συσχέτισή τους είναι μεγαλύτερη από ένα κατώφλι. Η χρονική περίοδος χωρίστηκε σε έξι περιόδους κάθε μία από τις οποίες είχε διάρκεια δύο ετών. Για την ανάλυση του δικτύου και την ανίχνευση των αλλαγών στη δομή του κατά τη διάρκεια της κρίσης, χρησιμοποιήθηκαν εργαλεία από την ανάλυση κοινωνικών δικτύων όπως η πυκνότητα του δικτύου και η εύρεση κλικών και συνιστωσών. Ακόμη, υπολογίστηκαν οι πιο σημαντικοί κόμβοι του δικτύου με βάση τις degree, closeness, betweenness και eigenvector centrality. Η ίδια μεθοδολογία εφαρμόστηκε και για την ανάλυση της συσχέτισης του όγκου συναλλαγών των μετοχών. Τέλος, μελετήθηκαν δίκτυα συσχέτισης τιμών μικρότερης χρονικής διάρκειας, κατά την οποία υπήρξε μεγάλη μεταβολή στην τιμή του γενικού δείκτη του χρηματιστηρίου
description: The aim of this thesis is to study the evolution of the stock correlation network which arises from the correlation of stock returns of large cap and mid cap indexes of Greek stock market for the period 2005-2016. The Pearson correlation coefficient was used to calculate correlations of shares while the creations of the networks were based on the assumption that two shares are linked with an edge if their correlation is greater than a threshold. The time period was divided into six periods, each of which lasted for two years. For the network analysis and the detection of changes in its structure during the crisis, tools from social network analysis such as edge density and cliques and components identification were used. Furthermore, the most important nodes of the network were calculated based on degree, closeness, betweenness and eigenvector centrality. The same methodology was applied to analyze the transaction volume correlation among the stocks. Finally, price correlation networks that arose for shorter periods of time have been analyzed. During these periods, there was a big change in the general index of the stock market
On the collision of two shock waves in AdS5
Creators: name: Grumiller, Daniel
name: Romatschke, Paul
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We consider two ultrarelativistic shock waves propagating and colliding in five-dimensional Anti-de-Sitter spacetime. By transforming to Rosen coordinates, we are able to find the form of the metric shortly after the collision. Using holographic renormalization, we calculate the energy-momentum tensor on the boundary of AdS space for early times after the collision. Via the gauge-gravity duality, this gives some insights on bulk dynamics of systems created by high energy scattering in strongly coupled gauge theories. We find that Bjorken boost-invariance is explicitely violated at early times and we obtain an estimate for the thermalization time in this simple system.
description: 15 pages, 1 figure; v2: clarifications on boost-invariance and appendix added; v3: minor modifications, references added, matches published version
Phase separation of a driven granular gas in annular geometry
Creators: name: Diez-Minguito, Manuel
name: Meerson, Baruch
Publisher: name: arXiv
Year: 2006
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Physical sciences

description: This work investigates phase separation of a monodisperse gas of inelastically colliding hard disks confined in a two-dimensional annulus, the inner circle of which represents a "thermal wall". When described by granular hydrodynamic equations, the basic steady state of this system is an azimuthally symmetric state of increased particle density at the exterior circle of the annulus. When the inelastic energy loss is sufficiently large, hydrodynamics predicts spontaneous symmetry breaking of the annular state, analogous to the van der Waals-like phase separation phenomenon previously found in a driven granular gas in rectangular geometry. At a fixed aspect ratio of the annulus, the phase separation involves a "spinodal interval" of particle area fractions, where the gas has negative compressibility in the azimuthal direction. The heat conduction in the azimuthal direction tends to suppress the instability, as corroborated by a marginal stability analysis of the basic steady state with respect to small perturbations. To test and complement our theoretical predictions we performed event-driven molecular dynamics (MD) simulations of this system. We clearly identify the transition to phase separated states in the MD simulations, despite large fluctuations present, by measuring the probability distribution of the amplitude of the fundamental Fourier mode of the azimuthal spectrum of the particle density. We find that the instability region, predicted from hydrodynamics, is always located within the phase separation region observed in the MD simulations. This implies the presence of a binodal (coexistence) region, where the annular state is metastable. The phase separation persists when the driving and elastic walls are interchanged, and also when the elastic wall is replaced by weakly inelastic one.
description: 9 pages, 10 figures, to be published in PRE
Quadrupole-octupole coupling and the onset of octupole deformation in actinides
Creators: name: Nomura, K.
name: Rodríguez-Guzmán, R.
name: Robledo, L. M.
name: García-Ramos, J. E.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Nuclear Theory (nucl-th)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The evolution of quadrupole and octupole collectivity and their coupling is investigated in a series of even-even isotopes of the actinide Ra, Th, U, Pu, Cm, and Cf with neutron number in the interval $130\leqslant N\leqslant 150$. The Hartree-Fock-Bogoliubov approximation, based on the parametrization D1M of the Gogny energy density functional, is employed to generate potential energy surfaces depending upon the axially-symmetric quadrupole and octupole shape degrees of freedom. The mean-field energy surface is then mapped onto the expectation value of the $sdf$ interacting-boson-model Hamiltonian in the boson condensate state as to determine the strength parameters of the boson Hamiltonian. Spectroscopic properties related to the octupole degree of freedom are produced by diagonalizing the mapped Hamiltonian. Calculated low-energy negative-parity spectra, $B(E3;3^{-}_{1}\to 0^{+}_{1})$ reduced transition rates, and effective octupole deformation suggest that the transition from nearly spherical to stable octupole-deformed, and to octupole vibrational states occurs systematically in the actinide region.
description: 12 pages, 12 figures
Retinal toxicity after initial administration of nivolumab and ipilimumab
Creators: name: Kilani, Adnan
name: Vounotrypidis, Efstathios
name: König, Susanna F.
name: Wolf, Armin
Publisher: name: Universität Ulm
Year: 2023
Subjects: subject: DDC 610 / Medicine & health
subject: Retinal degeneration
subject: Nivolumab; Adverse effects
subject: Ipilimumab; Adverse effects
subject: Immune checkpoint inhibitors
subject: Netzhautdegeneration
subject: Immun-Checkpoint
subject: Arzneimittelnebenwirkung

description: Background. To present a rare case of a bilateral immune checkpoint inhibitor- (ICI-) induced photoreceptor injury with a bacillary layer detachment (BALAD) and a dissection of the photoreceptor inner and outer segment, accompanied by ICI-induced Vogt-Koyanagi-Harada- (VKH-) like uveitis after initial administration of nivolumab and ipilimumab. Case Presentation. A 52-year-old female with metastatic malignant cutaneous melanoma experiencing bilateral progressive visual acuity reduction, after treatment initiation with 1 mg/kg nivolumab and 3 mg/kg ipilimumab two weeks prior symptom onset. An extensive laboratory workup, including uveitis workup, onconeuronal and retinal antibodies, ruled out a paraneoplastic autoimmune disorder and a granulomatous disease. Furthermore, a B-scan was performed to exclude a posterior scleritis. Ensuing temporary treatment discontinuation of nivolumab and complete discontinuation of ipilimumab, treatment with high-dose systemic steroids was initiated, which resulted in alleviation of her symptoms and stability of ocular findings. Conclusions. ICIs can induce significant ocular side effects. As ocular inflammation can be well controlled using systemic steroids, treatment with ICIs can be continued whenever possible, in particular, if there is a good treatment response of the systemic malignancy.
Optimization of a wood-waste fuelled, indirectly-fired gas turbine cogeneration plant for sawmill applications
Creators: name: Zaradic, Andrea Melissa
Publisher: name: University of British Columbia
Year: 2009

description: Forests are a primary natural resource in the province of British Columbia. Harvested trees are delivered to sawmills which produce lumber for domestic and export markets, wood chips for the pulp and paper industry and large volumes of wood waste. Traditionally, wood waste has been disposed of by open incineration. The government of British Columbia has mandated that by 1996, all forms of open burning must be eliminated. In the past this form of biomass waste had very limited economic value due to its limited application and use. The most common use for forest residues was in pulp and paper mills where it was utilized as a fuel for steam boilers for generating both heat and electricity. Until recently, very little incentive existed for manufacturers of wood wastes to generate electricity and/or heat due to the very low electricity and natural gas prices. This scenario is beginning to change due to increased environmental standards. Cogeneration with wood waste, i.e. the simultaneous production of heat and electricity, is proposed as a viable alternative for supplying the heat and power requirements of a sawmill. Cogeneration has been utilized in the past, in the pulp and paper sector, but has had very limited application in the sawmill industry. In analyzing the application of a cogeneration system the amount of heat and power to be produced must be determined. In some cases, the system is sized to match the electrical power requirements, while in other cases it is sized to meet the thermal requirements. In order to achieve the best economic return from the system, both heat and power must be produced accordingly. These amounts are not intuitively obvious and an optimization technique known as linear programming has been incorporated in this analysis to determine the optimum production levels of heat and power. In general it was found that cash flow was maximized when the cogeneration system was sized to meet the thermal requirements of the sawmill. Production of electricity was not particularly attractive due to low electricity rates. The overall conclusions indicate that cogeneration is an economically attractive option for disposing of wood wastes for those sawmills which require large amounts of process heat, typically in the range of 20,000 kW (68 MMBtu/hr).
Measurement of Bd mixing using opposite-side flavor tagging
Creators: name: D0 Collaboration
name: Abazov, V. M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We report on a measurement of the $B^0_d$ mixing frequency and the calibration of an opposite-side flavor tagger in the DØexperiment. Various properties associated with the $b$ quark on the opposite side of the reconstructed $B$ meson were combined using a likelihood-ratio method into a single variable with enhanced tagging power. Its performance was tested with data, using a large sample of reconstructed semileptonic $B \to μ\dzero X$ and $B \to μ\dst X$ decays, corresponding to an integrated luminosity of approximately 1 fb$^{-1}$. The events were divided into groups depending on the value of the combined tagging variable, and an independent analysis was performed in each group. Combining the results of these analyses, the overall effective tagging power was found to be eD^2 = (2.48 \pm 0.21 (stat.) ^{+0.08}_{-0.06} (syst.))%. The measured $B^0_d$ mixing frequency dmd = 0.506 \pm 0.020 {\rm (stat) \pm 0.016 (syst) ps}^{-1} is in good agreement with the world average value.
description: 19 pages, 17 figures, submitted to Phys. Rev. D
Revealing shifts from mastery of knowledge to problem solving in assessments of a tertiary physics programme
Creators: name: Cornell, Alan S.
name: Padayachee, Kershree
Publisher: name: arXiv
Year: 2021
Subjects: subject: Physics Education (physics.ed-ph)
subject: FOS: Physical sciences

description: There is an increasing pressure for lecturers to work with two goals. First, they need to ensure their undergraduate students have a good grasp of the knowledge and skills of the intellectual field. In addition, they need to prepare graduates and postgraduates for careers both within and outside of academia. The problem addressed by this paper is how assessments may reveal a shift of focus from a mastery of knowledge to a work-focused orientation. This shift is examined through a case study of physics and the sub-discipline of theoretical physics as intellectual fields. The evidence is assessment tasks given to students at different points of their studies from first year to doctoral levels. By examining and analysing the assessment tasks using concepts from Legitimation Code Theory (LCT), we demonstrate how the shifts in the assessments incrementally lead students from a pure disciplinary focus to one that enables students to potentially pursue employment both within and outside of academia. In doing so, we also highlight the usefulness of LCT as a framework for evaluating the preparation of science students for diverse workplaces.
description: 20 pages, journal details: Journal of Education, 2021, Issue 83
Σχέσεις ερπετοπανίδας – ενδιαιτήματος στο περιαστικό δάσος Θεσσαλονίκης, Σέιχ Σου
Creators: name: Τακόλα, Ελένη Ελδα Νικολάου
Publisher: name: Aristotle University of Thessaloniki
Year: 2018
Subjects: Επιλογή μικροενδιαιτήματος
Ποικιλότητα ερπετών
Εύρος οικοθέσης
Microhabitat selection
Reptile diversity
Niche breadth

description: Η Ελλάδα, παρά το μικρό της μέγεθος, αποτελεί μια από τις χώρες με την υψηλότερη ποικιλότητα ειδών ερπετοπανίδας στην Ευρώπη. Εντούτοις, οι πληθυσμοί των ερπετών απειλούνται από την κλιματική αλλαγή, την απώλεια και υποβάθμιση των ενδιαιτημάτων τους και την εξάπλωση του αστικού ιστού. Σκοπός της παρούσας έρευνας ήταν να διερευνηθούν οι σχέσεις μεταξύ ενδιαιτήματος και ερπετών σε ένα τυπικό μεσογειακό οικοσύστημα. Επιμέρους στόχους αποτέλεσαν η περιγραφή των περιβαλλοντικών χαρακτηριστικών του μικροενδιαιτήματος που επιλέγουν τα ερπετά και η εκτίμηση των προτύπων ποικιλότητας σε διαφορετικούς τύπους ενδιαιτημάτων. Η παρούσα μελέτη πραγματοποιήθηκε στην ευρύτερη περιοχή του περιαστικού δάσους Θεσσαλονίκης, Σεϊχ Σου. Συνολικά πραγματοποιήθηκαν 196 καταγραφές 20 ειδών ερπετών. Η ποικιλότητα και ο πλούτος των ειδών των κοινοτήτων των ερπετών βρέθηκαν να διαφέρουν στους διαφορετικούς τύπους ενδιαιτήματος της περιοχής μελέτης. Επίσης, ο υπολογισμός του εύρους της οικοθέσης κάθε είδους επέτρεψε την κατηγοριοποίησή τους σε ευρύτοπα και στενότοπα. Αναφορικά με τα χαρακτηριστικά του μικροενδιαιτήματος, το υψόμετρο, ο βαθμός συγκόμωσης και η κάλυψη του εδάφους επηρεάζουν την παρουσία των ερπετών. Είναι αναγκαία η περαιτέρω έρευνα της επιλογής του μικροενδιαιτήματος των ερπετών και η παρακολούθηση των πληθυσμών τους προκειμένου να ληφθούν απαραίτητα μέτρα προστασίας των απειλούμενων ειδών
description: Greece, despite its small area, holds among the highest herpetofauna diversities in Europe. However, Greek populations of reptile species are in decline due to climate change, degradation and loss of habitats and the spread of cities over broad territories. The aim of this study was to examine the relationships between reptiles and their habitat in a typical Mediterranean ecosystem. The objectives were the description of microenvironmental preferences of reptiles and the estimation of diversity patterns in different habitat types. The study area was the suburban forest of Thessaloniki (Seich Sou). The sample size was 196 specimens of 20 species. Diversity and species richness of reptile communities differed among habitat types. Moreover, niche breadth calculation allowed the characterization of species as stenotopic or eurytopic. Reptile presence was affected by the altitude, canopy cover and ground cover. Microhabitat preferences of these species should be studied more systematically in order to monitor population trends and to conserve endangered species
Eternally accelerating spacelike braneworld cosmologies
Creators: name: Mochizuki, Riuji
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We construct an eternally inflating spacelike brane world model. If the space dimension of the brane is three (SM2) or six (SM5) for M theory or four (SD3) for superstring theory, a time-dependent $n$-form field would supply a constant energy density and cause exponentially expansion of the spacelike brane. In these cases, the hyperbolic space perpendicular to the brane would not vary in size. In the other cases, however, the extra space would vary in size.
description: 8 pages, Mod. Phys. Lett. A Vol.21, No.40(2006) 2989-2996
Percolation thresholds on triangular lattice for neighbourhoods containing sites up-to the fifth coordination zone
Creators: name: Malarz, K.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We determine thresholds $p_c$ for random-site percolation on a triangular lattice for all available neighborhoods containing sites from the first to the fifth coordination zones, including their complex combinations. There are 31 distinct neighbourhoods. The dependence of the value of the percolation thresholds $p_c$ on the coordination number $z$ are tested against various theoretical predictions. The newly proposed single scalar index $ξ=\sum_i z_ir_i^2/i$ (depending on the coordination zone number $i$, the neighbourhood coordination number $z$ and the square-distance $r^2$ to sites in $i$-th coordination zone from the central site) allows to differentiate among various neighbourhoods and relate $p_c$ to $ξ$. The thresholds roughly follow a power law $p_c\proptoξ^{-γ}$ with $γ\approx 0.710(19)$.
description: 7 pages, 4 figures, 1 table, 31 thresholds
Symmetries of Conservation Laws
Creators: name: Konjik, Sanja
Publisher: name: arXiv
Year: 2007
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35L65;35D99;46F30;58D19

description: The aim of this paper is to apply techniques of symmetry group analysis in solving two systems of conservation laws: a model of two strictly hyperbolic conservation laws and a zero pressure gas dynamics model, which both have no global solution, but whose solution consists of singular shock waves. We show that these shock waves are solutions in the sense of 1-strong association. Also, we compute all projectable symmetry groups and show that they are 1-strongly associated, hence transform existing solutions in the sense of 1-strong association into other solutions.
Structural entropy and spatial decay of quasimodes in Vogel spirals
Creators: name: Prado, Marcus
name: Sgrignuoli, Fabrizio
name: Chen, Yuyao
name: Negro, Luca Dal
name: Pinheiro, Felipe A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We investigate the spatial decay and temporal localization properties of quasimodes (i.e., scattering resonances) of two-dimensional Vogel spirals, composed of deterministic, aperiodic arrays of electric dipoles. By determining the structural entropy and localization maps of Vogel spirals using the Green's matrix method, we show that three distinctive decay types of quasimodes coexist in Vogel spirals: exponential, power-law, and Gaussian. While the exponential and the power-law decays typically occur in disordered media and multifractal systems, respectively, the Gaussian decay is demonstrated to characterize, on average, the most localized quasimodes of Vogel spirals, both spatially (smallest participation ratios) and temporarily (longest lifetimes). These decay forms are demonstrated by a no-fitting analysis of the localization maps, independently corroborated by calculating the electric field in real space, which also provides a direct evidence of the algebraic spatial decay of critical quasimodes. Altogether our findings unveil a rich spectrum of both long-lived and spatially localized quasimodes that coexist in Vogel spirals and can be of direct relevance to novel optical functionalities for applications to light sources and sensing devices.
description: 8 pages, 3 figures
Interrupting Real-Time IoT Tasks: How Bad Can It Be to Connect Your Critical Embedded System to the Internet?
Creators: name: Behnke, Ilja
name: Pirl, Lukas
name: Thamsen, Lauritz
name: Danicki, Robert
name: Polze, Andreas
name: Kao, Odej
Publisher: name: arXiv
Year: 2021
Subjects: subject: Networking and Internet Architecture (cs.NI)
subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: FOS: Computer and information sciences

description: Embedded systems have been used to control physical environments for decades. Usually, such use cases require low latencies between commands and actions as well as a high predictability of the expected worst-case delay. To achieve this on small, low-powered microcontrollers, Real-Time Operating Systems (RTOSs) are used to manage the different tasks on these machines as deterministically as possible. However, with the advent of the Internet of Things (IoT) in industrial applications, the same embedded systems are now equipped with networking capabilities, possibly endangering critical real-time systems through an open gate to interrupts. This paper presents our initial study of the impact network connections can have on real-time embedded systems. Specifically, we look at three aspects: The impact of network-generated interrupts, the overhead of the related networking tasks, and the feasibility of sharing computing resources between networking and real-time tasks. We conducted experiments on two setups: One treating NICs and drivers as black boxes and one simulating network interrupts on the machines. The preliminary results show that a critical task performance loss of up to 6.67% per received packet per second could be induced where lateness impacts of 1% per packet per second can be attributed exclusively to ISR-generated delays.
description: IPCCC 2020: 39th International Performance Computing and Communications Conference
Web robot detection in portal of scientific publications
Creators: name: Λυρτζή, Δόμνα Αστερίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2018
Subjects: Επιβλεπόμενη Μηχανική Μάθηση
Ανίχνευση Ρομπότ
Σημασιολογικά Στοιχεία
Supervised Machine Learning
Web Robot Detection
Semantic Features

description: Στόχος της διατριβής είναι η μελέτη διαφορετικών τεχνικών επιβλεπόμενης μηχανικής μάθησης για την ανίχνευση επίσκεψης αυτόματων συστημάτων (ρομπότ) σε διαδικτυακές πύλες επιστημονικών δημοσιεύσεων. Η είσοδος για την εφαρμογή των τεχνικών μάθησης προκύπτει συνθέτοντας τις πληροφορίες που βρίσκονται στα αρχεία καταγραφής των κινήσεων των επισκεπτών του ιστότοπου με σημασιολογικές φόρμουλες. Όλο και περισσότεροι διακομιστές επιστημονικού υλικού επιλέγουν να διατηρήσουν το υλικό τους σε σημασιολογικές δομές, ώστε να είναι ευκόλως προσβάσιμοι. Υποθέτοντας ότι σε έναν ανθρώπινο διαδικτυακό επισκέπτη, η σημασιολογική δομή ενός ιστότοπου βοηθάει την περιήγησή του, η γνώση αυτής της σημασιολογίας μπορεί να αποτελέσει παράγοντα διάκρισης των ανθρώπων από τα ρομπότ. Ύστερα από την εξαγωγή σημασιολογικών χαρακτηριστικών από τα αρχεία καταγραφής και τη συγκριτική μελέτη εφαρμογής των δεδομένων σε διαφορετικές μεθόδους επιβλεπόμενης μηχανικής μάθησης, συμπεραίνεται ότι η χρήση τους μπορεί να βελτιώσει τα αποτελέσματα ανίχνευσης διαδικτυακών ρομπότ με τη εφαρμογή δέντρων απόφασης
description: The main aim of this thesis is to study different supervised machine learning techniques to detect web robots in web portal servers by combining the information of the log files with semantic information about the requested resources. More and more servers maintain their resources into semantic structures so that can be easily found and accessed. Having the assumption that semantics can be useful to distinguish a human visit from a web robot visit, different semantic features were explored in combination with syntactic features that log files offer. An extended research, with a comparative study of different supervised machine learning techniques applied to the same dataset, showed that the inclusion of semantic information can lead to better detection results with the construction of decision trees
Revealing the physical properties of gas accreting to haloes in the EAGLE simulations
Creators: name: Wright, Ruby J.
name: Lagos, Claudia del P.
name: Power, Chris
name: Correa, Camila A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The inflow of cosmological gas onto haloes, while challenging to directly observe and quantify, plays a fundamental role in the baryon cycle of galaxies. Using the EAGLE suite of hydrodynamical simulations, we present a thorough exploration of the physical properties of gas accreting onto haloes -- namely, its spatial characteristics, density, temperature, and metallicity. Classifying accretion as ``hot'' or `` cold'' based on a temperature cut of $10^{5.5}{\rm K}$, we find that the covering fraction ($f_{\rm cov}$) of cold-mode accreting gas is significantly lower than the hot-mode, with $z=0$ $f_{\rm cov}$ values of $\approx 50\%$ and $\approx 80\%$ respectively. Active Galactic Nuclei (AGN) feedback in EAGLE reduces inflow $f_{\rm cov}$ values by $\approx 10\%$, with outflows decreasing the solid angle available for accretion flows. Classifying inflow by particle history, we find that gas on first-infall onto a halo is metal-depleted by $\approx 2$~dex compared to pre-processed gas, which we find to mimic the circum-galactic medium (CGM) in terms of metal content. We also show that high (low) halo-scale gas accretion rates are associated with metal-poor (rich) CGM in haloes below $10^{12}M_{\odot}$, and that variation in halo-scale gas accretion rates may offer a physical explanation for the enhanced scatter in the star-forming main sequence at low ($\lesssim10^{9}M_{\odot}$) and high ($\gtrsim10^{10}M_{\odot}$) stellar masses. Our results highlight how gas inflow influences several halo- and galaxy-scale properties, and the need to combine kinematic and chemical data in order to confidently break the degeneracy between accreting and outgoing gas in CGM observations.
description: 24 pages, 13 figures. Final version accepted for publication in MNRAS
Role of $B_c^+ \to B_{s,d}^{(*)} \, \bar \ell \, ν_\ell$ in the Standard Model and in the search for BSM signals
Creators: name: Colangelo, P.
name: De Fazio, F.
name: Loparco, F.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: The decays $B_c^+ \to B_{a} \bar \ell ν_\ell$ and $B_c^+ \to B_{a}^{*}(\to B_a γ) \bar \ell ν_\ell$, with $a=s,d$ and $\ell=e,μ$, are studied in the Standard Model (SM) and in the extension based on the low-energy Hamiltonian comprising the full set of dimension-$6$ semileptonic $c \to s,d$ operators with left-handed neutrinos. Tests of $μ/e$ universality are investigated using such modes. The heavy quark spin symmetry is applied to relate the relevant hadronic matrix elements and to exploit lattice QCD results on $B_c$ form factors. Optimized observables are selected, and the pattern of their correlations is studied to identify the effects of the various operators in the extended low-energy Hamiltonian.
description: LaTex, 15 pages, 17 figures. Figures and references added, version to appear in PRD
Higgs Boson Mass from Orbifold GUTs with Split Supersymmetry
Creators: name: Gogoladze, Ilia
name: Li, Tianjun
name: Senoguz, V. N.
name: Shafi, Qaisar
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We consider orbifold GUTs with N=1 supersymmetry in which the Standard Model (SM) gauge couplings are unified at M_GUT =~ 2 x 10^16 GeV with one of the third family (charged) Yukawa couplings. With split supersymmetry the SM Higgs mass is estimated to be 131 +/- 10 GeV for gauge-top quark Yukawa unification, which increases to 146 +/- 8 GeV for gauge-bottom quark (or gauge-tau lepton) Yukawa unification.
description: 1+15 pages, 7 figures. v2: Higgs mass estimations and figures slightly changed due to a correction in our calculations
Is the silicate emission feature only influenced by grain size?
Creators: name: Voshchinnikov, N. V.
name: Henning, Th.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The flattening of the 10mu silicate emission feature observed in the spectra of T Tauri and Herbig Ae/Be stars is usually interpreted as an indicator of grain growth. We show in this paper that a similar behaviour of the feature shape occurs when the porosity of composite grains varies. The fluffy aggregates, having inclusions of different sizes, were modeled by multi-layered spheres consisting of amorphous carbon, amorphous silicate and vacuum. It is also found that the inclusion of crystalline silicates in composite porous particles can lead to a shift of the known resonances and production of new ones.
description: accepted by Astronomy & Astrophysics Letters; small revision after referee report
European Association of Urology risk stratification predicts outcome in patients receiving PSMA-PET-planned salvage radiotherapy for biochemical recurrence following radical prostatectomy
Creators: name: Scharl, Sophia
name: Zamboglou, Constantinos
name: Strouthos, Iosif
name: Farolfi, Andrea
name: Serani, Francesca
name: Koerber, Stefan A.
name: Debus, Jürgen
name: Peeken, Jan Caspar
name: Vogel, Marco M. E.
name: Kroeze, Stephanie G. C.
name: Guckenberger, Matthias
name: Krafcsik, Manuel
name: Hruby, George
name: Emmett, Louise
name: Schmidt-Hegemann, Nina-Sophie
name: Trapp, Christian
name: Spohn, Simon K. B.
name: Henkenberens, Christoph
name: Mayer, Benjamin
Publisher: name: Universität Ulm
Year: 2024
Subjects: subject: DDC 610 / Medicine & health
subject: Prostatic neoplasms
subject: Positron-emission tomography
subject: Prostatic neoplasms; Ddiagnostic imaging
subject: Prostate-specific antigen
subject: Prostatakrebs
subject: Positronen-Emissions-Tomografie
subject: Prostataspezifisches Membranantigen

description: Purpose The European Association of Urology (EAU) proposed a risk stratification (high vs. low risk) for patients with biochemical recurrence (BR) following radical prostatectomy (RP). Here we investigated whether this stratification accurately predicts outcome, particularly in patients staged with PSMA-PET. Methods For this study, we used a retrospective database including 1222 PSMA-PET-staged prostate cancer patients who were treated with salvage radiotherapy (SRT) for BR, at 11 centers in 5 countries. Patients with lymph node metastases (pN1 or cN1) or unclear EAU risk group were excluded. The remaining cohort comprised 526 patients, including 132 low-risk and 394 high-risk patients. Results The median follow-up time after SRT was 31.0 months. The 3-year biochemical progression-free survival (BPFS) was 85.7 % in EAU low-risk versus 69.4 % in high-risk patients (p = 0.002). The 3-year metastasis-free survival (MFS) was 94.4 % in low-risk versus 87.6 % in high-risk patients (p = 0.005). The 3-year overall survival (OS) was 99.0 % in low-risk versus 99.6 % in high-risk patients (p = 0.925). In multivariate analysis, EAU risk group remained a statistically significant predictor of BPFS (p = 0.003, HR 2.022, 95 % CI 1.262–3.239) and MFS (p = 0.013, HR 2.986, 95 % CI 1.262–7.058). Conclusion Our data support the EAU risk group definition. EAU risk grouping for BCR reliably predicted outcome in patients staged lymph node-negative after RP and with PSMA-PET before SRT. To our knowledge, this is the first study validating the EAU risk grouping in patients treated with PSMA-PET-planned SRT.