cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Adaptive Optics Correction of the Wavefront Distortions Induced by Segments Misalignment in Extremely Large Telescope
Creators: name: Yaitskova, Natalia
name: Verinaud, Christophe
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The capability of the adaptive optics to correct for the segmentation error is analyzed in terms of the residual wavefront RMS and the power spectral density of the phase. The analytical model and the end-to-end simulation give qualitatively equal results justifying the significance of the geometrical matching between segmentation geometry and the actuators/subaperture distribution of the adaptive optics. We also show that the design of the wavefront sensor is rather critical.
description: 12 pages, 17 figures
Acoustic spin Hall effect in strong spin-orbit metals
Creators: name: Kawada, Takuya
name: Kawaguchi, Masashi
name: Funato, Takumi
name: Kohno, Hiroshi
name: Hayashi, Masamitsu
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We report on the observation of the acoustic spin Hall effect that facilitates lattice motion induced spin current via spin orbit interaction (SOI). Under excitation of surface acoustic wave (SAW), we find a spin current flows orthogonal to the propagation direction of a surface acoustic wave (SAW) in non-magnetic metals. The acoustic spin Hall effect manifests itself in a field-dependent acoustic voltage in non-magnetic metal (NM)/ferromagnetic metal (FM) bilayers. The acoustic voltage takes a maximum when the NM layer thickness is close to its spin diffusion length, vanishes for NM layers with weak SOI and increases linearly with the SAW frequency. To account for these results, we find the spin current must scale with the SOI and the time derivative of the lattice displacement. Such form of spin current can be derived from a Berry electric field associated with time varying Berry curvature and/or an unconventional spin-lattice interaction mediated by SOI. These results, which imply the strong coupling of electron spins with rotating lattices via the SOI, show the potential of lattice dynamics to supply spin current in strong spin orbit metals.
Analysis of hydrological data for subsurface drainage design for an arid area in India
Creators: name: Prairie, Katherine Anne
Publisher: name: University of British Columbia
Year: 2009

description: In the semi-arid to arid State of Rajasthan, 90% of the annual rainfall occurs as convective storms during the monsoon season. The suitability of a Markov chain analysis to model rainfall in this region was evaluated. A 5 day transition probability matrix accurately predicts sequences of wet and dry days based solely on the state of the preceding day. Both a daily model and an event-based model were used to describe rainfall pattern and distribution. Although the daily model is a traditional choice, the event-based model produced superior results. The event-based model describes the distribution of rainfall during a storm, the length of dry periods between rainfall events, and rainfall depths. The drainage coefficient derived from the normal value analysis, is 32.26 mm using the daily model, compared with 10.69 and 21.77 mm for the event-based models. The most cost-effective drainage coefficient is 10.69 mm derived from the 0.1 mm threshold event model. The Penman (1963) method best estimated ET[sub c] over both seasons as well as within each season. The Jensen-Haise method, when adjusted by a correction factor of 1.15 for ET[sub alfalfa], produced comparable estimates of ETc. The minimal climatic data required for the Jensen-Haise method makes it the most suitable evapotranspiration method for this area. A set of coefficients, ranging from 0.73 to 1.40, was developed to convert pan vaporation measurements to ET[sub JH]*. General crop coefficients for each development stage were determined from the generalized cropping pattern of the Chambal Command area. A water balance using effective wet year rainfall and evapotranspiration for the Kharif season was used to calculate the drainage requirement. The drainage requirement for the 178 ha Daglawada test plot is 749.2 and 1165.3 (x10³) m³, for return periods of 5 and 10 years, respectively. The leaching requirement of 0.0309, can be met with the Kharif season rainfall expected in wet years with return periods of 5 or more years, and normal years with return periods of 10 or more years.
Sensitivity below the standard quantum limit in gravitational wave detectors with Michelson-Fabry-Perot readout
Creators: name: Belfi, J.
name: Marin, F.
Publisher: name: arXiv
Year: 2008
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We calculate the quantum noise limited displacement sensitivity of a Michelson-Fabry-Perot (MFP) with detuned cavities, followed by phase-sensitive homodyne detection. We show that the standard quantum limit can be surpassed even with resonant cavities and without any signal-recycling mirror nor additional cavities. Indeed, thanks to the homodyne detection, the output field quadrature can be chosen in such a way to cancel the effect of input amplitude fluctuations, i.e., eliminating the force noise. With detuned cavities, the modified opto-mechanical susceptivity allows to reach unlimited sensitivity for large enough (yet finite) optical power. Our expressions include mirror losses and cavity delay effect, for a realistic comparison with experiments. Our study is particularly devoted to gravitational wave detectors and we consider both an interferometer with free-falling mirrors, and a MFP as readout for a massive detector. In the latter case, the sensitivity curve of the recently conceived 'DUAL' detector, based on two acoustic modes, is obtained.
Start up ομάδες και ο ρόλος των κοινωνικών μέσων ιστού στη σύσταση τους:
Creators: name: Σπανού, Αναστασία Χαραλάμπους
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: Ομάδες
Σύσταση
Δίκτυα
Groups
Recommendations
Networks

description: Στην παρούσα διπλωματική εργασία, επιχειρείται η βιβλιογραφική διερεύνηση της έννοιας των μικρών ομάδων, η πορεία μέχρι την σύστασης τους, η απομακρυσμένη συνεργασία των μελών καθώς και ο ρόλος των διαδικτυακών κοινωνικών μέσω στην διαδικασία αυτή. Η αναζήτηση του βαθμού διείσδυσης των κοινωνικών δικτύων στην ανεύρεση και επιλογή μελών καθώς και η συμπερίληψη στοιχείων της προσωπικότητας στα προτασιακά συστήματα των επαγγελματικών δικτύων αποτελούν πρωταρχικό σκοπό αυτής της εργασίας. Η τεχνολογία και οι συμβατικοί μέθοδοι που κυριαρχούν στην δημιουργία και λειτουργία μιας διαδικτυακής ομάδας θα αποτελέσουν βασικά θέματα προς ανάλυση και προβληματισμό. Τέλος η τεκμηρίωση των ελλείψεων που εντοπίστηκαν στη σύσταση μιας ομάδας μέσω των κοινωνικών δικτύων και της χρήσης προτασιακών συστημάτων αποτελεί έναν από τους βασικότερους στόχους της διπλωματικής με την ελπίδα οι παρατηρήσεις αυτές να συνεισφέρουν σε μελλοντικές μελέτες και έρευνες αλλά και στην βελτίωση των προτασιακών συστημάτων.
description: An exploration of the concept of small groups and of the remote collaboration between their members is attempted in the present M. Sc. thesis. Furthermore, an investigation of the process that leads to group formation as well as of how social networks contribute towards it. The elucidation of the role that such networks play in the detection and selection of group members, and the way through which elements of personality are integrated in recommendations systems constitute the primary purpose of the present study. Technology and conventional methods that are dominant in the creation and operation of an internet group will be primary subjects of analysis. Finally, the documentation of the deficiencies which were noted in the recommendation systems of social networks is one of the main aims of the thesis. Ultimately, the present work aspires to contribute to future studies and research in the field as well as to the improvement of recommendation systems.
Ανάπτυξη μοντέλων συγκράτησης αναλυτών σε στήλες υγρής χρωματογραφίας με τη βοήθεια της ανάλυσης κύριων συνιστωσών (PCA).:
Creators: name: Τσουμαχίδου, Σοφία Αναστασίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: ανάλυση κύριων συνιστωσών
μοντέλα συγκράτησης
πρόβλεψη
PCA
retention models
prediction

description: Αναπτύχθηκαν τρία μοντέλα συγκράτησης αναλυτών σε στήλες υγρής χρωματογραφίας με τη βοήθεια της ανάλυσης κύριων συνιστωσών (PCA). Τα μοντέλα PCA παρουσιάζουν παρόμοια χαρακτηριστικά με το μοντέλο LSER (Linear Solvation Energy Relationship). Αποδεικνύεται ότι η ικανότητα προσαρμογής των παραπάνω μοντέλων είναι πολύ καλύτερη του LSER μοντέλου, η απόδοση του οποίου μπορεί να βελτιωθεί αισθητά με τη χρήση τεχνητών νευρικών δικτύων (ANN). Επιπλέον, μελετήθηκε η δυνατότητα χρήσης των μοντέλων PCA, αλλά και του μοντέλου LSER, για την πρόβλεψη του χρόνου συγκράτησης ενώσεων σε συνθήκες κάτω από τις οποίες δεν έχουν προηγούμενα μελετηθεί, με τη βοήθεια τριών σετ δεδομένων διαφορετικών ενώσεων και συνθηκών.
description: Three retention models for liquid chromatography are developed using principal component analysis (PCA). It is shown that they exhibit features similar to that of the model based on linear solvation energy relationship (LSER). However, the fitting performance of the PCA models is better than that of the LSER model, the performance of which can be considerably improved by the use of artificial neural networks (ANN). In addition, the possibility of using the proposed models as well as the LSER model to predict the retention times of solutes under chromatographic conditions at which these solutes have never been studied is also examined by means of three data sets of analytes consisting of non – polar compounds to polar compounds with a variety of functional groups.
Millimeter Wave Localization: Slow Light and Enhanced Absorption
Creators: name: Scales, John A.
name: Carr, L. D.
name: McIntosh, D. B.
name: Freilikher, Valentin
name: Bliokh, Yu. P.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: We exploit millimeter wave technology to measure the reflection and transmission response of random dielectric media. Our samples are easily constructed from random stacks of identical, sub-wavelength quartz and Teflon wafers. The measurement allows us to observe the characteristic transmission resonances associated with localization. We show that these resonances give rise to enhanced attenuation even though the attenuation of homogeneous quartz and Teflon is quite low. We provide experimental evidence of disorder-induced slow light and superluminal group velocities, which, in contrast to photonic crystals, are not associated with any periodicity in the system. Furthermore, we observe localization even though the sample is only about four times the localization length, interpreting our data in terms of an effective cavity model. An algorithm for the retrieval of the internal parameters of random samples (localization length and average absorption rate) from the external measurements of the reflection and transmission coefficients is presented and applied to a particular random sample. The retrieved value of the absorption is in agreement with the directly measured value within the accuracy of the experiment.
description: revised and expanded
Μάθηση μέσω σχεδιασμού και η διδασκαλία της ελληνικής γλώσσας ως δεύτερη/ξένη σε ενήλικες Ρομά:
Creators: name: Τζιώτζιου, Αναστασία Κωνσταντίνου
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: Μάθηση μέσω σχεδιασμού
Διδασκαλία γλώσσας
Ρομά
Leaning by design
Language teaching
Roma people

description: Η παρούσα εργασία, διεκπεραιώθηκε στα πλαίσια του προγράμματος «Εκπαίδευση παιδιών Ρομά» και έλαβε χώρα σε έναν από τους καταυλισμούς των Ρομά στο νησί της Ρόδου. Η βάση της έρευνας ήταν να διδαχθούν δέκα μαθησιακές ενότητες που αφορούν την διδασκαλία της ελληνικής γλώσσας. Οι ενότητες αυτές σχεδιάστηκαν για την συγκεκριμένη ομάδα μέσω της εφαρμογής της «Μάθησης μέσω σχεδιασμού». Αρχική υπόθεση είναι ότι οι συμμετέχοντες θα επιλέξουν να διδαχθούν καθημερινά πρακτικά θέματα που θα βελτιώσουν τις καθημερινές τους ανάγκες και την ποιότητα ζωής τους. Αρχικά, εξετάσαμε την ορολογία που χρησιμοποιείται και τη μεθοδολογία που αφορά τη διδασκαλία μιας γλώσσας. Στη συνέχεια, παρουσιάζεται αναλυτικά η μεθοδολογία που χρησιμοποιήθηκε για τη διεξαγωγή της έρευνας. Μέσω συνεντεύξεων, παρατήρησης και καταγραφής ημερολογίου εντοπίζονται οι ανάγκες της ομάδας και κατά συνέπεια οι προτιμήσεις τους σχετικά με το περιεχόμενο των μαθημάτων. Τέλος, οι ενότητες αυτές διδάχθηκαν και κατόπιν αξιολογήθηκαν. Κλείνοντας την εργασία, καταγράφονται τα αποτελέσματα της έρευνας και παρουσιάζεται το υλικό που διδάχθηκε.
description: This study was conducted within the project "Education of Roma children" and took place in one of the Roma camps on the island of Rhodes. The basis of this research was to teach ten learning modules on the teaching of the Greek language. These modules are designed for this specific group through the implementation of "Learning by design." The initial hypothesis is that the participants will choose to be taught everyday practical topics that will improve their daily needs and quality of life. Initially, we examined the methodology and the terminology used for teaching a language. Afterwards the methodology used to conduct the research is presented in great detail. Through interviews, observation and keeping detailed logs we identified the needs of the group and consequently their preferences about the contents of the course. In the end, these modules were taught and then evaluated. The results of this research along with the material taught are presented at the end of this study.
Proof of triviality of $λϕ^4$ theory
Creators: name: Frasca, Marco
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We show that a recent analysis in the strong coupling limit of the $λϕ^4$ theory proves that this theory is indeed trivial giving in this limit the expansion of a free quantum field theory. We can get in this way the propagator with the renormalization constant and the renormalized mass. As expected the theory in this limit has the same spectrum as a harmonic oscillator. Some comments about triviality of the Yang-Mills theory in the infrared are also given.
description: 5 pages, 1 figure. Updated references and added some more. Comparison with lattice data of the gluon propagator is given finding excellent agreement. Accepted for publication in International Journal of Modern Physics A
Portfólio de serviços OPERAS para a investigação e publicação aberta
Creators: name: Delmazo, Carol
name: Caliman, Lorena
Publisher: name: Zenodo
Year: 2024

description: Apresentação realizada na sessão Demos, da 15ª Conferência Lusófona de Ciência Aberta, na Escola Superior de Enfermagem do Porto (ESEP), de 01 a 04 de outubro de 2024.
Structural, electronic, and magnetic properties of nearly-ideal $J_{\rm eff}$ $=$ 1/2 iridium halides
Creators: name: Reig-i-Plessis, D.
name: Johnson, T. A.
name: Lu, K.
name: Chen, Q.
name: Ruff, J. P. C.
name: Upton, M. H.
name: Williams, T. J.
name: Calder, S.
name: Zhou, H. D.
name: Clancy, J. P.
name: Aczel, A. A.
name: MacDougall, G. J.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Heavy transition metal magnets with $J_{\rm eff}$ $=$ 1/2 electronic ground states have attracted recent interest due to their penchant for hosting new classes of quantum spin liquids and superconductors. Unfortunately, model systems with ideal $J_{\rm eff}$ $=$ 1/2 states are scarce due to the importance of non-cubic local distortions in most candidate materials. In this work, we identify a family of iridium halide systems [i.e. K$_2$IrCl$_6$, K$_2$IrBr$_6$, (NH$_4$)$_2$IrCl$_6$, and Na$_2$IrCl$_6 \cdotp $ 6(H$_2$O)] with Ir$^{4+}$ electronic ground states in extremely close proximity to the ideal $J_{\rm eff}$ $=$ 1/2 limit, despite a variation in the low-temperature global crystal structures. We also find ordered magnetic ground states for the three anhydrous systems, with single crystal neutron diffraction on K$_2$IrBr$_6$ revealing Type-I antiferromagnetism. This spin configuration is consistent with expectations for significant Kitaev exchange in a face-centered-cubic magnet.
description: 14 pages, 9 figures
Purification of partially degraded diethanolamine solutions
Creators: name: Abdi, Majid Abedinzadegan
Publisher: name: University of British Columbia
Year: 2009

description: Alkanolamine solutions are widely used in the gas processing industries for the removal of acid gases (e.g. C0₂and H₂S). These solutions frequently become contaminated with amine degradation products, heat stable salts, heavy hydrocarbons and particulates. The contaminants pose serious problems to the sound performance of gas processing plants. Although distillation is the most promising method to separate the contaminants, conventional single-effect flash reclaimers suffer from several problems such as incomplete recovery of amine and low product purity due to the close volatility of amines and certain degradation products. It is shown that these problems can be alleviated by using a novel multi-stage distillation process in which a special inert carrier liquid is employed. The inert liquid ensures proper fluid flows in the distillation column and increases the amine recovery. The desired physical properties of the inert liquid were identified and the liquid was selected accordingly. The vapour-liquid and liquid-liquid equilibrium data for mixtures of diethanolamine, its principal degradation products, water and the inert liquid were investigated. These data are essential to design and simulate the process under various operating conditions. The appropriate thermodynamic models required to represent the equilibrium data were determined and a number of design options, including the conventional singlestage flash process, were evaluated by means of the ASPEN process simulator. Advantages of the new process developed in this study include high amine recoveries and good amine purity. Thermal degradation of amines and potential fouling of heat transfer tubes in conventional amine reclaimers is avoided since the amine mixtures are not passed through the heat exchanger.
Supernova Neutrino Nucleosynthesis of Light Elements with Neutrino Oscillations
Creators: name: Yoshida, T.
name: Kajino, T.
name: Yokomakura, H.
name: Kimura, K.
name: Takamura, A.
name: Hartmann, D. H.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Light element synthesis in supernovae through neutrino-nucleus interactions, i.e., the nu-process, is affected by neutrino oscillations in the supernova environment. There is a resonance of 13-mixing in the O/C layer, which increases the rates of charged-current nu-process reactions in the outer He-rich layer. The yields of 7Li and 11B increase by about a factor of 1.9 and 1.3, respectively, for a normal mass hierarchy and an adiabatic 13-mixing resonance, compared to those without neutrino oscillations. In the case of an inverted mass hierarchy and a non-adiabatic 13-mixing resonance, the increase in the 7Li and 11B yields is much smaller. Observations of the 7Li/11B ratio in stars showing signs of supernova enrichment could thus provide a unique test of neutrino oscillations and constrain their parameters and the mass hierarchy.
description: 5 pages, 3 figures, accepted for publication in Physical Review Letters
Hydrogen H$α$ line polarization in solar flares. Theoretical investigation of atomic polarization by proton beams considering self-consistent NLTE polarized radiative transfer
Creators: name: Stepan, Jiri
name: Heinzel, Petr
name: Sahal-Brechot, Sylvie
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Context. We present a theoretical review of the effect of impact polarization of a hydrogen H$α$ line due to an expected proton beam bombardment in solar flares. Aims. Several observations indicate the presence of the linear polarization of the hydrogen H$α$ line observed near the solar limb above 5% and preferentially in the radial direction. We theoretically review the problem of deceleration of the beam originating in the coronal reconnection site due to its interaction with the chromospheric plasma, and describe the formalism of the density matrix used in our description of the atomic processes and the treatment of collisional rates. Methods. We solve the self-consistent NLTE radiation transfer problem for the particular semiempirical chromosphere models for both intensity and linear polarization components of the radiation field. Results. In contrast to recent calculations, our results show that the energy distribution of the proton beam at H$α$ formation levels and depolarizing collisions by background electrons and protons cause a significant reduction of the effect below 0.1%. The radiation transfer solution shows that tangential resonance-scattering polarization dominates over the impact polarization effect in all considered models. Conclusions. In the models studied, proton beams are unlikely to be a satisfying explanation for the observed linear polarization of the H$α$ line.
description: 11 pages, 11 figures, accepted for publication in A&A
Η Δολοφονία Λαμπράκη στον Τύπο της Θεσσαλονίκης
Creators: name: Αυγέρη, Θεοδώρα Πέτρου
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: Λαμπράκης
Δολοφονία
Τύπος
Lambrakis
Assassination
Νewspapers

description: Στόχος της έρευνάς μας είναι να ανιχνεύσουμε τον τρόπο με τον οποίο υποδέχθηκαν την είδηση της δολοφονικής επίθεσης εναντίον του βουλευτή Λαμπράκη οι εφημερίδες της Θεσσαλονίκης και πώς τα νοηματοδότησαν πολιτικά. Τι ήταν αυτό που καθόρισε τη στάση τους απέναντι στα γεγονότα, τους πρωταγωνιστές της υπόθεσης, την αστυνομία, την κυβέρνηση, τα κόμματα της αντιπολίτευσης. Συνέβαλαν οι εφημερίδες της Θεσσαλονίκης στην αποκάλυψη της αλήθειας και των πραγματικών συνθηκών κάτω από τις οποίες σκοτώθηκε ο συνεργαζόμενος με την ΕΔΑ βουλευτής; Πώς διαχειρίστηκαν αυτή την ύλη οι δημοσιογράφοι των εφημερίδων της Θεσσαλονίκης; Είχαν αποκλειστικότητες, αποκαλυπτικά ρεπορτάζ, αποκλειστικές συνεντεύξεις ή δηλώσεις, ανταποκρίσεις από την Αθήνα, την υπόλοιπη Ελλάδα και το εξωτερικό; Η εντοπιότητα επηρέασε την θέαση των γεγονότων και τη θέση απέναντι σε αυτά; Ποιοι είναι οι άνθρωποι πίσω από τις ανώνυμες λέξεις, αλλά και τις υπογραφές, όπου αυτές υπάρχουν; Η μελέτη μας επικεντρώνεται στα δημοσιεύματα τεσσάρων εφημερίδες της Θεσσαλονίκης, της ΜΑΚΕΔΟΝΙΑΣ, της ΘΕΣΣΑΛΟΝΙΚΗΣ, του ΕΛΛΗΝΙΚΟΥ ΒΟΡΡΑ και του ΕΛΕΥΘΕΡΟΥ ΛΑΟΥ, από τις 23 μέχρι και τις 27 Μαΐου 1963, την ημέρα της αναχώρησης της σορού του Λαμπράκη από τη Θεσσαλονίκη με προορισμό την Αθήνα.
description: The aim of our research has been to detect the way the newspapers of Thessaloniki received the announcement of the murderous attack against the MP Lambrakis and what kind of political meaning they assigned it. What has been the factor that determined their stance towards the developments, the key figures in the events, the policy, the government, the opposition parties. Did the newspapers of Thessaloniki play a role in revealing the truth and the real circumstances, under which the co-operating MP with the EDA party died? How did the journalists of the newspapers of Thessaloniki handle the material? Did they manage to make scoops, revealing reports, exclusive interviews or statements, reporting from Athens, the rest of Greece and the abroad? Did the proximity affect the way of seeing the developments and their position towards them? Who have been the people behind the anonymous words, but also the signatures, wherever they are to be found? Our research focuses on the stories run by four newspapers of Thessaloniki: MAKEDONIA, THESSALONIKI, ELLINIKOS VORRAS & ELEFTHEROS LAOS from 23th to 27th May 1963, the day the body of Lambrakis departed from Thessaloniki to its final destination, Athens.
Deeply Virtual Compton Scattering on nucleons and nuclei in generalized vector meson dominance model
Creators: name: Goeke, K.
name: Guzey, V.
name: Siddikov, M.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We consider Deeply Virtual Compton Scattering (DVCS) on nucleons and nuclei in the framework of generalized vector meson dominance (GVMD) model. We demonstrate that the GVMD model provides a good description of the HERA data on the dependence of the proton DVCS cross section on Q^2, W (at Q^2=4 GeV^2) and t. At Q^2 = 8 GeV^2, the soft W-behavior of the GVMD model somewhat underestimates the W-dependence of the DVCS cross section due to the hard contribution not present in the GVMD model. We estimate 1/Q^2 power-suppressed corrections to the DVCS amplitude and the DVCS cross section and find them large. We also make predictions for the nuclear DVCS amplitude and cross section in the kinematics of the future Electron-Ion Collider. We predict significant nuclear shadowing, which matches well predictions of the leading-twist nuclear shadowing in DIS on nuclei.
description: 25 pages, 9 figures, 1 table
The Impact of Disturbed Galaxy Clusters on the Kinematics of Active Galactic Nuclei
Creators: name: Bilton, Lawrence E.
name: Pimbblet, Kevin A.
name: Gordon, Yjan A.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We produce a kinematic analysis of AGN-hosting cluster galaxies from a sample 33 galaxy clusters selected using the X-ray Clusters Database (BAX) and populated with galaxies from the Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8). The 33 galaxy clusters are delimited by their relative intensity of member galaxy substructuring as a proxy to core merging to derive two smaller sub-samples of 8 dynamically active (merging) and 25 dynamically relaxed (non-merging) states. The AGN were selected for each cluster sub-sample by employing the WHAN diagram to the strict criteria of log$_{10}$([NII]/H$α$)$\geq-0.32$ and EW$_{\mathrm{H}α}$ $\geq$ 6Å, providing pools of 70 merging and 225 non-merging AGN sub-populations. By co-adding the clusters to their respective dynamical states to improve the signal-to-noise of our AGN sub-populations we find that merging galaxy clusters on average host kinematically active AGN between 0-1.5 $r_{200}$ as $r_{200}\rightarrow0$, where their velocity dispersion profile (VDP) presents a significant deviation from the non-AGN sub-population VDP by $\gtrsim3σ$. This result is indicative that the AGN-hosting cluster galaxies have recently coalesced onto a common potential. Further analysis of the composite distributions illustrate non-merging AGN-hosting sub-populations have, on average, already been accreted and predominantly lie within backsplash regions of the projected phase-space. This suggests merging cluster dynamical states hold relatively younger AGN sub-populations kinematically compared with those found in non-merging cluster dynamical states.
description: Accepted for publication in the Monthly Notices of the Royal Astronomical Society; 14 pages, 6 figures
DataCite Metadata Schema Documentation for the Publication and Citation of Research Data and Other Research Outputs v4.5
Creators: name: DataCite Metadata Working Group
Publisher: name: DataCite
publisherIdentifier: https://ror.org/04wxnsj81
publisherIdentifierScheme: ROR
Year: 2024

description: Introduction: About DataCite; About the DataCite Metadata Schema; Version 4.5 Update; Citation. DataCite Metadata Properties: Overview; 1. Identifier; 2. Creator; 3. Title; 4. Publisher; 5. PublicationYear; 6. Subject; 7. Contributor; 8. Date; 9. Language; 10. ResourceType; 11. AlternateIdentifier; 12. RelatedIdentifier; 13. Size; 14. Format; 15. Version; 16. Rights; 17. Description; 18. GeoLocation; 19. FundingReference; 20. RelatedItem. Appendices: Appendix 1: Controlled List Definitions; Appendix 2: Earlier Version Update Notes; Appendix 3: Standard values for unknown information. Mappings: DataCite to Dublin Core Mapping 4.5; FORCE11 Software Citation Principles Mapping; PIDINST Schema Mapping. Guidance: Citation of dynamic datasets; Support for software citation; Using RelatedItem for publication information and related resources. XML Schema and Examples.
Testing abundance-age relations beyond solar analogues with Kepler LEGACY stars
Creators: name: Morel, Thierry
name: Creevey, Orlagh L.
name: Montalban, Josefina
name: Miglio, Andrea
name: Willett, Emma
Publisher: name: arXiv
Year: 2020
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present abundances of 21 elements in a sample of 13 bright FG dwarfs drawn from the Kepler LEGACY sample to examine the applicability of the abundance-age relations to stars with properties strongly departing from solar. These stars have precise asteroseismic ages that can be compared to the abundance-based estimates. We analyse the well-known binary 16 Cyg AB for validation purposes and confirm the existence of a slight metal enhancement (~0.02 dex) in the primary, which might arise from planetary formation/ingestion. We draw attention to systematic errors in some widely-used catalogues of non-seismic parameters that may significantly bias asteroseismic inferences. In particular, we find evidence that the ASPCAP Teff scale used for the APOKASC catalogue is too cool for dwarfs and that the [Fe/H] values are underestimated by ~0.1 dex. We compare seismic ages to those inferred from empirical abundance-age relations based on ages from PARSEC isochrones and abundances obtained in the framework of the HARPS-GTO program. These calibrations take into account a dependency with the stellar effective temperature, metallicity, and/or mass. We find that the seismic and abundance-based ages differ on average by 1.5-2 Gyrs, while taking into account a dependency with one or two stellar parameters in the calibrations leads to a global improvement of up to ~0.5 Gyr. However, even in that case we find that seismic ages are systematically larger by ~0.7 Gyr. We argue that it may be ascribed to a variety of causes including the presence of small zero-point offsets between our abundances and those used to construct the calibrations or to the choice of the set of theoretical isochrones. The conclusions above are supported by the analysis of literature data for a larger number of Kepler targets. [Abridged]
description: 23 pages, 16 figures. Accepted for publication in A&A
Heavy quark thermodynamics in full QCD
Creators: name: Petrov, Konstantin
name: Collaboration, RBC-Bielefeld
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: We analyze the large-distance behaviour of static quark-anti-quark pair correlations in QCD. The singlet free energy is calculated and the entropy contribution to it is identified allowing us to calculate the excess internal energy. The free energy has a sharp drop in the critical region, leading to sharp peaks in both excess entropy and internal energy.
description: talk given at Quark Matter 2006
Circular geodesics in Kerr-Newman-Kasuya black hole
Creators: name: Khan, Saeed Ullah
name: Ren, Jingli
Publisher: name: arXiv
Year: 2020
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences
subject: 83-06

description: This article explores the characteristics of ergoregion, horizons and circular geodesics around a Kerr-Newman-Kasuya black hole. We investigate the effect of spin and dyonic charge parameters on ergoregion, event horizon and static limit surface of the said black hole. We observed that both electric, as well as magnetic charge parameters, results in decreasing the radii of event horizon and static limit, whereas increasing the area of ergoregion. The obtained results are compared with that acquired from Kerr and Schwarzschild black holes. Moreover, we figured out the photons orbit of circular null geodesics and studied the angular velocity of a particle within ergoregion.
description: 5 pages, 2 figures
Scalable Many-Objective Pathfinding Benchmark Suite
Creators: name: Weise, Jens
name: Mostaghim, Sanaz
Publisher: name: arXiv
Year: 2020
Subjects: subject: Neural and Evolutionary Computing (cs.NE)
subject: FOS: Computer and information sciences

description: Route planning also known as pathfinding is one of the key elements in logistics, mobile robotics and other applications, where engineers face many conflicting objectives. However, most of the current route planning algorithms consider only up to three objectives. In this paper, we propose a scalable many-objective benchmark problem covering most of the important features for routing applications based on real-world data. We define five objective functions representing distance, traveling time, delays caused by accidents, and two route specific features such as curvature and elevation. We analyse several different instances for this test problem and provide their true Pareto-front to analyse the problem difficulties. We apply three well-known evolutionary multi-objective algorithms. Since this test benchmark can be easily transferred to real-world routing problems, we construct a routing problem from OpenStreetMap data. We evaluate the three optimisation algorithms and observe that we are able to provide promising results for such a real-world application. The proposed benchmark represents a scalable many-objective route planning optimisation problem enabling researchers and engineers to evaluate their many-objective approaches.
description: 10 pages
DQ white-dwarf stars with low C abundance: Possible progenitors
Creators: name: Scóccola, C. G.
name: Althaus, L. G.
name: Serenelli, A. M.
name: Rohrmann, R. D.
name: Córsico, A. H.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The present paper focuses on the evolution of hydrogen-deficient white dwarfs with the aim of exploring the consequences of different initial envelope structures on the carbon abundances expected in helium-rich, carbon-contaminated DQ white dwarfs. In particular, the evolutionary link between the DQs with low detected carbon abundances and the PG1159, extreme horizontal branch, and helium-rich R Coronae Borealis (RCrB) stars is explored. We present full evolutionary calculations that take a self-consistent treatment of element diffusion into account as well as expectations for the outer layer chemical stratification of progenitor stars upon entering the white dwarf regime. We find that PG1159 stars cannot be related to any DQ white dwarfs with low C abundances. Instead, we suggest that the latter could constitute the progeny of the giant, helium-rich RCrB stars.
description: 10 pages, 10 figures. Accepted for publication in Astronomy and Astrophysics
Detecting neutrino-transients with optical follow-up observations
Creators: name: Kowalski, Marek
name: Mohr, Anna
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: A novel method is presented which will enhance the sensitivity of neutrino telescopes to identify transient sources such as Gamma-Ray Bursts (GRBs) and core-collapse Supernovae (SNe). Triggered by the detection of high energy neutrino events from IceCube or other large scale neutrino telescopes, an optical follow-up program will allow the identification of the transient neutrino source. We show that once the follow-up program is implemented, the achievable sensitivity of IceCube to neutrinos from SNe and GRBs would increase by a factor of 2-3. The program can be realized with a small network of automated 1-2 meter telescopes and has rather modest observing time requirements.
description: 10 pages, 3 figures, consistent with version published in Astropart. Phys
A study of colloidal hydrocracking catalysts prepared in reverse micelles
Creators: name: Hall, Andrew Graham
Publisher: name: University of British Columbia
Year: 2009

description: Slurry phase reactors employing dispersed metal sulfide catalysts offer the potential of high conversion with minimal coke yield for the hydrocracking of heavy oil. Currently, the dispersed catalysts are prepared by the addition of organometallic compounds to the heavy oil feed, but this synthesis technique offers little control over the size of the catalyst particles. Colloidal suspensions of a wide range of metals and metal compounds in hydrocarbons can be prepared from water-soluble metal salts dissolved within the water pools of a microemulsion. This synthesis technique allows for the simple control of particle size, a factor which together with their narrow size distribution makes these colloids potentially attractive as dispersed heavy oil hydrocracking catalysts. The synthesis of reduced metal and metal sulfide colloids in the water pools of the water/polyoxyethylene-4-laurylether/hexane microemulsion was investigated in the present study. The sizes of the reverse micelles were determined by dynamic light scattering (DLS), while the reduced Ni, Co and Fe colloids and the Ni, Co and Fe sulfide colloids were characterized by DLS, transmission electron spectroscopy (TEM), energy dispersive x-ray spectrometry (EDX) and xray photoelectron spectroscopy (XPS). The catalytic activity of the metal sulfide catalysts was also determined using the hydrocracking of diphelylmethane as a model reaction. The water:surfactant ratio (ψ) and metal ion concentration were found to be the key factors affecting the size of the reverse micelles in the water/PE4LE/hexane system. Monodisperse Co and Fe colloids with sizes ranging from 10-23 nm were prepared in the microemulsion system by the addition of N₂Fl₄, and the size of the metal colloids was found to be directly related to ψ. Ni, Co and Fe sulfide colloids were prepared in reverse micelles using 5% H₂S in H₂, and XPS analysis identified MS and CoS₂ on the surface of these colloids. The metal sulfides proved difficult to characterize due to their extreme sensitivity to atmospheric oxygen. The Fe sulfide colloids oxidized readily, and could not be identified using XPS. The NiS and CoS₂ colloids had average sizes of 67 and 71 nm respectively (as determined by TEM), and were more polydisperse than the reduced metal colloids prepared in the same system. The metal sulfide catalysts prepared in the water/polyoxyethylene-4-laurylether/hexane microemulsion were found to he less active for the hydrocracking of diphenylmethane than a dispersed catalyst prepared from the decomposition of Co naphthenate. The crystallite size was similar for both catalyst preparations (20-30 nm), suggesting that diffusion limitations may have controlled the rate of reaction in the case of the aggregated metal sulfide catalyst prepared in the microemulsion.
Thomas E. Dewey: Consensus Liberal
Creators: name: Harkenrider, Zach
Publisher: name: University of Rochester
Year: 2024
Subjects: classificationCode: 43
subject: History, heritage and archaeology
classificationCode: 430321
subject: North American history
classificationCode: 470307
subject: English language

description: Students in two of Professor Robert Westbrook's courses in American intellectual history, "The American Mind, 1600-1865" (History 267) and "The American Mind, 1865-1990" (History 268), use manuscript materials as part of a research assignment. This assignment, called "Other People's Mail," requires that students transcribe a document and write an introduction to it, placing the document in its context and suggesting the ways in which it bears on significant themes in the course.

Please Note: All rights regarding the papers rest with the authors. The images of the manuscripts may not be reproduced without obtaining prior written permission from the Department of Rare Books and Special Collections.
This document was adapted from a webpage hosted on the Rare Books, Special Collections, and Manuscripts website, before being converted into a static document and uploaded to URRR on 2024-10-07.
Escape dynamics of active particles in multistable potentials
Creators: name: Militaru, Andrei
name: Innerbichler, Max
name: Frimmer, Martin
name: Tebbenjohanns, Felix
name: Novotny, Lukas
name: Dellago, Christoph
Publisher: name: arXiv
Year: 2020
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Rare transitions between long-lived metastable states underlie a great variety of physical, chemical and biological processes. Our quantitative understanding of reactive mechanisms has been driven forward by the insights of transition state theory. In particular, the dynamic framework developed by Kramers marks an outstanding milestone for the field. Its predictions, however, do not apply to systems driven by non-conservative forces or correlated noise histories. An important class of such systems are active particles, prominent in both biology and nanotechnology. Here, we trap a silica nanoparticle in a bistable potential. To emulate an active particle, we subject the particle to an engineered external force that mimics self-propulsion. We investigate the active particle's transition rate between metastable states as a function of friction and correlation time of the active force. Our experiments reveal the existence of an optimal correlation time where the transition rate is maximized. This novel \emph{active turnover} is reminiscent of the much celebrated Kramers turnover despite its fundamentally different origin. Our observations are quantitatively supported by a theoretical analysis of a one-dimensional model. Besides providing a deeper understanding of the escape dynamics of active particles in multistable potentials, our work establishes a new, versatile experimental platform to study particle dynamics in non-equilibrium settings.
The gauge theory of dislocations: static solutions of screw and edge dislocations
Creators: name: Lazar, Markus
name: Anastassiadis, Charalampos
Publisher: name: arXiv
Year: 2008
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We investigate the T(3)-gauge theory of static dislocations in continuous solids. We use the most general linear constitutive relations bilinear in the elastic distortion tensor and dislocation density tensor for the force and pseudomoment stresses of an isotropic solid. The constitutive relations contain six material parameters. In this theory both the force and pseudomoment stresses are asymmetric. The theory possesses four characteristic lengths l1, l2, l3 and l4 which are given explicitely. We first derive the three-dimensional Green tensor of the master equation for the force stresses in the translational gauge theory of dislocations. We then investigate the situation of generalized plane strain (anti-plane strain and plane strain). Using the stress function method, we find modified stress functions for screw and edge dislocations. The solution of the screw dislocation is given in terms of one independent length l1=l4. For the problem of an edge dislocation, only two characteristic lengths l2 and l3 arise with one of them being the same l2=l1 as for the screw dislocation. Thus, this theory possesses only two independent lengths for generalized plane strain. If the two lengths l2 and l3 of an edge dislocation are equal, we obtain an edge dislocation which is the gauge theoretical version of a modified Volterra edge dislocation. In the case of symmetric stresses we recover well known results obtained earlier.
description: 33 pages, 17 figures
Mechanical Vibrational Relaxation of NO Scattering from Metal and Insulator Surfaces: When and Why Are They Different?
Creators: name: Yin, Rongrong
name: Jiang, Bin
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: NO scattering from metallic and insulating surfaces represent contrasting benchmark systems for understanding energy transfer at gas-surface interface. Strikingly different behaviors of highly vibrationally excited NO scattered from Au(111) and LiF(001) were observed and attributed to disparate electronic structures between metals and insulators. Here, we reveal an alternative mechanical origin of this discrepancy by comparative molecular dynamics simulations with globally accurate adiabatic neural network potentials of both systems. We find that highly-vibrating NO can reach for the high dissociation barrier on Au(111), by which vibrational energy can largely transfer to translation/rotation and further dissipate into substrate phonons. This mechanical energy transfer channel is forbidden in the purely repulsive NO/LiF(001) system or for low-vibrating NO on Au(111), where molecular vibration is barely coupled to other degrees of freedom. Our results emphasize that the initial state and potential energy landscape concurrently influence the mechanical energy transfer dynamics of gas-surface scattering.
Orthogonal Range Searching on Prioritized Points:
Creators: name: Κοσματόπουλος, Ανδρέας Κωνσταντίνου
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: Ορθογώνια Ερωτήματα Περιοχής
Προτεραιότητα
Κυριαρχία
Orthogonal Range Searching
Priority
Dominance

description: Τα τελευταία 35 χρόνια τα ερωτήματα περιοχής, είναι ένα σημαντικό τμήμα έρευνας, στο πεδίο της υπολογιστικής γεωμετρίας. Το πρόβλημα των ερωτημάτων περιοχής, αφορά στην εύρεση όλων των σημείων ενός συνόλου δεδομένων, που βρίσκονται μέσα σε ένα ορισμένο από τον χρήστη ερώτημα περιοχής. Στην παρούσα εργασία, μελετούμε το πρόβλημα των ορθογωνίων ερωτημάτων περιοχής σε σημεία με προτεραιότητες, στο οποίο σε κάθε σημείο ανατίθεται ένα βάρος, αναλόγως με την σπουδαιότητα του στο σύνολο δεδομένων. Ένα πιο εξειδικευμένο πρόβλημα είναι αυτό των κ κορυφαίων σημείων με τη μέγιστη κυριαρχία, στο οποίο το βάρος σε κάθε σημείο είναι ίσο με τη βαθμολογία κυριαρχίας του. Το πρόβλημα των κ κορυφαίων σημείων με τη μέγιστη κυριαρχία, έχει σκοπό να βρει τα κ σημεία με το μεγαλύτερο βάρος μέσα σε ένα ορισμένο από τον χρήστη ερώτημα περιοχής. Προτείνουμε δομές δεδομένων και αλγορίθμους για να επιλύσουμε το πρόβλημα των κ κορυφαίων σημείων, σε διαφορετικά ερωτήματα περιοχής. Επίσης παρέχουμε τα άνω φράγματα για τον χρόνο απάντησης του ερωτήματος και το χωρικό κόστος κάθε δομής δεδομένων.
description: For the past 35 years, range searching has been an important area of research in the computational geometry field. The range searching problem is concerned with finding all the points of a dataset that exist in a user-provided query range. In this work, we study the problem of orthogonal range searching in prioritized points, in which each point is assigned a weight according to its importance in the dataset. A specific problem is the top-k dominating problem in which the weight of each point is equal to its domination score. The top-k dominating problem aims to find the k points with the highest weight inside a user-provided query range. We propose data structures and algorithms for solving the top-k dominating problem in different query ranges. Furthermore, we provide upper bounds for the query answering time and the space cost of each data structure.