cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Novel Collective Excitations and the Quasi-Particle Picture of Quarks Coupled with a Massive Boson at Finite Temperature
Creators: name: Kitazawa, Masakiyo
name: Kunihiro, Teiji
name: Nemoto, Yukio
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Motivated by the observation that there may exist hadronic excitations even in the quark-gluon plasma (QGP) phase, we investigate how the properties of quarks, especially within the quasi-particle picture, are affected by the coupling with bosonic excitations at finite temperature (T), employing Yukawa models with a massive scalar (pseudoscalar) and vector (axial-vector) boson of mass m. The quark spectral function and the quasi-dispersion relations are calculated at one-loop order. We find that there appears a three-peak structure in the quark spectral function with a collective nature when T is comparable with m, irrespective of the type of boson considered. Such a multi-peak structure was first found in a chiral model yielding scalar composite bosons with a decay width. We elucidate the mechanism through which the new quark collective excitations are realized in terms of the Landau damping of a quark (an antiquark) induced by scattering with the thermally excited boson, which gives rise to mixing and hence a level repulsion between a quark (antiquark) and an antiquark-hole (quark-hole) in the thermally excited antiquark (quark) distribution. Our results suggest that the quarks in the QGP phase can be described within an interesting quasi-particle picture with a multi-peak spectral function. Because the models employed here are rather generic, our findings may represent a universal phenomenon for fermions coupled to a massive bosonic excitation with a vanishing or small width. The relevance of these results to other fields of physics, such as neutrino physics, is also briefly discussed. In addition, we describe a new aspect of the plasmino excitation obtained in the hard-thermal loop approximation.
description: 41 pages, 39 eps figures, version to appear in Prog. Theor. Phys, comments on effects of the quark mass and the chemical potential added, typos corrected, some figures improved
Robust learning from noisy, incomplete, high-dimensional experimental data via physically constrained symbolic regression
Creators: name: Reinbold, Patrick A. K.
name: Kageorge, Logan M.
name: Schatz, Michael F.
name: Grigoriev, Roman O.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Pattern Formation and Solitons (nlin.PS)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Physical sciences

description: Machine learning offers an intriguing alternative to first-principles analysis for discovering new physics from experimental data. However, to date, purely data-driven methods have only proven successful in uncovering physical laws describing simple, low-dimensional systems with low levels of noise. Here we demonstrate that combining a data-driven methodology with some general physical principles enables discovery of a quantitatively accurate model of a non-equilibrium spatially-extended system from high-dimensional data that is both noisy and incomplete. We illustrate this using an experimental weakly turbulent fluid flow where only the velocity field is accessible. We also show that this hybrid approach allows reconstruction of the inaccessible variables -- the pressure and forcing field driving the flow.
description: Under review at Nature Communications
Real-time fuzzy logic control of combined sewer flows
Creators: name: Tamaki, Robert Dean
Publisher: name: University of British Columbia
Year: 2009

description: The use of fuzzy logic for the real-time control of flows in a combined sewer system is examined in this thesis. Using a simple computer model, two different combined sewer overflow control scenarios were developed to test the effectiveness of a fuzzy rule base for controlling wet weather flows using off-line storage. The control objective of the first scenario was to capture the more highly contaminated first flush flows from a two sub-catchment drainage basin. A fuzzy controller was developed using heuristic methods that was found to be relatively effective in achieving the desired objective. The control objective of the second scenario was to capture the peak flow issuing from a single catchment. In this case, two different control strategies were employed. The first involved the construction of a fuzzy algorithm from a database of historical flow control data. That data was obtained manuallly by determining an optimal control response for each storm event using multiple repetitions of each simulation. The results of using this method, however, were found to be highly inadequate, due mostly to flawed methodology. The poor results prompted the development of the second method in which a crisp controller output was modified on-line by a fuzzy adjustment algorithm in response to real-time measurements of the state variables. This method yielded improved results over the first method but some inadequacies were still apparent. These inadequacies could be attributed primarily to the complexity of the control problem and the difficulty involved in representing those complexities heuristically so that they could be converted to a fuzzy algorithm. Specifically, the dimensionality of the control problem was found to be too large to be able to produce an effective fuzzy controller.
A Study of Compact Radio Sources in Nearby Face-on Spiral Galaxies. II. Multiwavelength Analyses of Sources in M51
Creators: name: Maddox, L. A.
name: Cowan, J. J.
name: Kilgard, R. E.
name: Schinnerer, E.
name: Stockdale, C. J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report the analysis of deep radio observations of the interacting galaxy system M51 from the Very Large Array, with the goal of understanding the nature of the population of compact radio sources in nearby spiral galaxies. We detect 107 compact radio sources, 64% of which have optical counterparts in a deep H$α$ Hubble Space Telescope image. Thirteen of the radio sources have X-ray counterparts from a {\em Chandra} observation of M51. We find that six of the associated H$α$ sources are young supernova remnants with resolved shells. Most of the SNRs exhibit steep radio continuum spectral indices onsistent with synchrotron emission. We detect emission from the Type Ic SN 1994I nearly a decade after explosion: the emission ($160\pm22 μ$Jy beam$^{-1}$ at 20 cm, $46\pm11 μ$Jy beam$^{-1}$ at 6cm, $α=-1.02\pm0.28$) is consistent with light curve models for Type Ib/Ic supernovae. We detect X-ray emission from the supernova, however no optical counterpart is present. We report on the analysis of the Seyfert 2 nucleus in this galaxy, including the evidence for bipolar outflows from the central black hole.
description: 22 pages, 8 figures (5 color) in separate files, AASTeX. Full resolution figures and preprint may be obtained by contacting lamaddox@astro.uiuc.edu. AJ accepted
Node-like excitations in superconducting PbMo6S8 probed by scanning tunneling spectroscopy
Creators: name: Dubois, C.
name: Petrovic, A. P.
name: Santi, G.
name: Berthod, C.
name: Manuel, A. A.
name: Decroux, M.
name: Fischer, O.
name: Potel, M.
name: Chevrel, R.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We present the first scanning tunneling spectroscopy study on the Chevrel phase PbMo6S8, an extreme type II superconductor with a coherence length only slightly larger than in high-Tc cuprates. Tunneling spectra measured on atomically flat terraces are spatially homogeneous and show well-defined coherence peaks. The low-energy spectral weight, the zero bias conductance and the temperature dependence of the gap are incompatible with a conventional isotropic s-wave interpretation, revealing the presence of low-energy excitations in the superconducting state. We show that our data are consistent with the presence of nodes in the superconducting gap.
description: To appear in PRB; 5 pages, 4 figures
A search for optical bursts from the rotating radio transient J1819-1458 with ULTRACAM
Creators: name: Dhillon, V. S.
name: Marsh, T. R.
name: Littlefair, S. P.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report on the search for optical bursts from J1819-1458, a member of the recently discovered Rotating Radio Transients (RRATs). J1819-1458 exhibits 3 millisecond bursts with a peak flux at 1.4 GHz of 3.6 Jy every ~3.4 minutes, implying that it is visible for only ~1 second per day at radio wavelengths. Assuming that the optical light behaves in a similar manner, the most sensitive way of detecting RRATs is hence not to take long exposures of the field, but instead to capture individual bursts using a high-speed camera mounted on a large aperture telescope. Using ULTRACAM on the 4.2-m William Herschel Telescope (WHT) we obtained 97100 images of the field of J1819-1458, each of 18.1 milliseconds exposure time and with essentially no dead-time between the frames. We find no evidence for bursts in u', g' and i' at magnitudes brighter than 15.1, 17.4 and 16.6 (5 sigma), corresponding to fluxes of less than 3.3, 0.4 and 0.8 mJy at 3560A, 4820A and 7610A, respectively.
description: 4 pages, 2 figures, accepted for publication in MNRAS
D3.1_High-level_Design_Document
Creators: name: Crespillo, Omar Garcia; Grosh, Anja; Fehr, Matthias; Zhu,Chen; Filip, Ales; Holik, Filip; Neri, Alessandro; Salvitti, Maurizio; Dionisio, Cesare; Xefteris, Panagiotis; Salvatori, Pietro; Capua, Roberto; Gattuso, Luca; Innocenti, Manuele; Giancolini, Marco; Kutik, Ondrej; Krajicek, Miroslav; Loupis, Michael; Spanoudakis, John
Publisher: name: Zenodo
Year: 2020
Subjects: Multimodal
AIMN

description: This deliverable is part of H2020 HELMET Project.
VaLiPro: Linear Programming Validator for Cluster Computing Systems
Creators: name: Sokolinsky, Leonid B.
name: Sokolinskaya, Irina M.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: FOS: Computer and information sciences

description: The article presents and evaluates a scalable algorithm for validating solutions of linear programming problems on cluster computing systems. The main idea of the method is to generate a regular set of points (validation set) on a small-radius hypersphere centered at the point of the solution under validation. The objective function is calculated for each point of the validation set that belongs to the feasible region. If all these values are less than or equal to the value of the objective function at the point under validation, then this point is the correct solution. The parallel implementation of the VaLiPro algorithm is performed in C++ through the parallel BSF-skeleton, which encapsulates all aspects related to the MPI-based parallelization of the program. We provide the results of large-scale computational experiments on a cluster computing system to study the scalability of the VaLiPro algorithm.
description: Submitted to "Supercomputing Frontiers and Innovations" journal
Rheology of high performance shotcrete
Creators: name: Beaupré, Denis
Publisher: name: University of British Columbia
Year: 2009

description: The main goal of this study was to develop high performance shotcrete and to provide a fundamental understanding of the shooting process. For this, a laboratory concrete pump, to pump and/or shoot a number of shotcrete mixes, and a rheometer, to measure the rheological properties on the fresh shotcrete, were designed and constructed. A model based on rheological behavior was finally developed to predict pumpability and shootability. The values of both flow resistance and torque viscosity were used to represent the rheological behavior of fresh shotcrete, which is similar to the Bingham model. Important fundamental relationships were obtained between rheological properties and pumping pressure, build-up thickness and compaction of shotcrete. With a new parameter, the fresh concrete aging rate, these relationships are used in a model which predicts pumpability and shootability. Production of high performance shotcrete can be carried out in two different ways: the “traditional method” consists of using superplasticizers while in the second method, the “concept of high initial air content” consists of using a very high air content to improve the workability. In both cases the requirements for good pumpability and shootability must be satisfied in order to be able to apply the shotcrete. These requirements are in conflict in terms of flow resistance: pumpability requires a low flow resistance while shootability requires a high flow resistance. The range of acceptable values for the flow resistance is reduced for mixes with high torque viscosity. The concept of a temporary high air content has some advantages over the traditional method: when compared to the use of superplasticizers only, the use of air, by reducing the torque viscosity, allows a wider range of acceptable values for the flow resistance to be maintained. Also, the compaction process allows a recovery of the flow resistance during shooting. Thus, this concept allows low water-cement ratio shotcrete having enhanced pumpability, shootability, strength, and durability to be produced. It could probably be an excellent way to avoid the use of accelerators which have adverse effects both on worker health and on concrete properties, especially the durability.
Η “Έκθεσις Κεφαλαίων Παραινετικών’’ του Διακόνου Αγαπητού. Μια Σύνοψη της Αυτοκρατορικής Ιδέας της εποχής του Ιουστινιανού.
Creators: name: Καβακιώτης, Πολύδωρος Νικόλαου
Publisher: name: Aristotle University of Thessaloniki
Year: 2017
Subjects: Διάκονος Αγαπητός
Αυτοκρατορική ιδέα
Ο ύψιστος στόχος της Βυζαντινής αυτοκρατορίας ήταν η παγκοσμιότητα
Deacon Agapetus
Imperial idea
The ultimate goal of the Byzantine Empire was universality

description: Σκοπός της διατριβής ήταν η μελέτη του έργου του Διακόνου Αγαπητού ’’Έκθεσις Κεφαλαίων Παραινετικών’’, στο οποίο υπογραμμίζονται στοιχεία χριστιανικής πολιτικής θεωρίας και φιλοσοφίας. Ο Διάκονος Αγαπητός προωθεί το θεμελιώδες αξίωμα της πολιτικής φιλοσοφίας της αυτοκρατορίας, κατά το οποίο η επίγεια δυναστεία είναι απότοκη της υπερκόσμιας αρχής, δοσμένη στον αυτοκράτορα, «νεύματι Θεού». Η άποψη αυτή του Αγαπητού είναι ένας «κοινός τόπος» της βυζαντινής πολιτικής θεωρίας, που στηρίζεται στη θεολογική σκέψη. Το ανωτέρω έργο του Αγαπητού, προβάλλει απεικονίσεις επίκαιρες κατά τον 6ο αιώνα και θεωρείται σαν «τυπική έκφραση της πολιτικής θεωρίας της εποχής του για τον ηγεμόνα». Η έννοια της αυτοκρατορικής ιδέας συνυφαίνεται με την οικουμενικότητα της Ρωμαϊκής αυτοκρατορίας. Έτσι ο αυτοκράτοράς της εθεωρείτο μοναδικός και αυτοκράτορας όλου του κόσμου. Αυτό συνεχίστηκε και στην περίοδο του Βυζαντίου. Ο αυτοκράτοράς του ήταν ο εκλεκτός του Θεού και ηγέτης όλων των υπολοίπων κρατών. Ο στόχος τόσο του ιδίου όσο και ο ύψιστος στόχος της Βυζαντινής αυτοκρατορίας ήταν η παγκοσμιότητα. Ο Διάκονος Αγαπητός, τέλος, θεωρεί ότι η άνιση κατανομή του πλούτου, εξωθεί στη δημιουργία δύο αντιπάλων κοινωνικών ομάδων, των πλουσίων και των ακτημόνων. Επομένως ο βασιλεύς οφείλει να ακολουθεί τέτοια οικονομική πολιτική ώστε «…..προς ισότητα την ανισότητα μετενεκτέον»
description: The aim of the present thesis was the study of Deacon's Agapetus 'Essay of Admonitory Chapters' in which are emphasized elements of Christian political and philosophical theories. Deacon Agapetus promotes the fundamental axiom of the imperial political philosophy according to which the earthly dynasty has been inherited from the ultra mundane dynasty, which is given to the emperor 'οn the nod of God'. This view of Agapetus is a common ground of the Byzantine political theory, which is based, in theological thinking. The above Agapetus essay displays timely depictions during the sixth century A.C. and is considered a 'typical expression of the political theory of Deacon Agapetus's era for the sovereign'. The meaning of the imperial idea is weaved together with the universality of the Roman empire. Therefore, the Roman emperor was considered unique and sole ruler of the world. The same was applied during the period of the Byzantine Empire. The Byzantine emperor was the chosen of God and ruler of all the remaining states. The aim of the emperor itself and the ultimate goal of the Byzantine Empire was universality. Lastly, Deacon Agapetus also states that unequal distribution of wealth urges the creation of two opposing social groups. Consequently, the King ought to follow a financial policy according to which 'to equality the inequality must convey
Εκπαίδευση ενηλίκων και κοινωνικός αποκλεισμός. Κριτική αποτίμηση των Σχολείων Δεύτερης Ευκαιρίας στη βάση της απελευθερωτικής/μετασχηματιστικής αγωγής
Creators: name: Λίμα, Αγγελική Χρήστου
Publisher: name: Aristotle University of Thessaloniki
Year: 2017
Subjects: Εκπαίδευση Ενηλίκων
Απελευθερωτική αγωγή
Σχολεία Δεύτερης Ευκαιρίας Adult education
Liberating education
Second Chance Schools

description: Η παρούσα εργασίας στοχεύει στην μελέτη και κριτική αποτίμηση των Σχολείων Δεύτερης Ευκαιρίας (ΣΔΕ), με βάση την απελευθερωτική/μετασχηματιστική αγωγή. Καθώς θεωρείται πως τα συγκεκριμένα σχολεία παρουσιάζουν πρόσφορο έδαφος για την εφαρμογή των μεθόδων της απελευθερωτικής και μετασχηματιστικής αγωγής, το ερευνητικό ενδιαφέρον εστιάζει στη μελέτη των χαρακτηριστικών της καθημερινής εκπαιδευτικής πραγματικότητας στα ΣΔΕ, όπως οι μέθοδοι και το περιεχόμενο διδασκαλίας, η παιδαγωγική σχέση, η εμπλοκή των εκπαιδευομένων στη διδακτική πράξη και η ανάπτυξη της κριτικής συνειδητοποίησής τους, και στη συνάφεια αυτών με τις αρχές την απελευθερωτικής αγωγής. Για ο σκοπό της εργασίας πραγματοποιήθηκαν ημι-δομημένες συνεντεύξεις με εκπαιδευτικούς και ποιοτικής ανάλυσης περιεχομένου. Στα συμπεράσματα αντανακλάται η σχετική απομάκρυνση της καθημερινής εκπαιδευτικής πρακτικής των ΣΔΕ και των αποτελεσμάτων της μαθησιακής διαδικασίας που σχετίζονται σε την κριτική συνειδητοποίηση των εκπαιδευομένων από τις αρχές της απελευθερωτικής αγωγής
description: This thesis aims at the critical appraisal of Second Chance Schools, on the basis of liberating/transformative education. Since Second Chance Schools are considered to provide fertile ground for introducing the methods of liberating/transformative education, the research interest focuses on the study of the coherence between the characteristics of the daily educational reality in Second Chance Schools, such as the methods and the context of instruction, the pedagogical relationship, the engagement of learners in the educational practice and the development of their critical consciousness, and the basic principles of liberating/transformative education. For this purpose, semi – structured interviews, both with learners and educators in Second Chance Schools, were conducted and analyzed, employing the qualitative content analysis method. Lastly, the conclusions reflect a certain distance between the everyday educational practice as well as the results regarding the learners' critical consciousness, and the main principals of liberating/ transformative education
Geometry of N=4, d=1 nonlinear supermultiplet
Creators: name: Bellucci, S.
name: Krivonos, S.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We construct the general action for $N=4, d=1$ nonlinear supermultiplet including the most general interaction terms which depend on the arbitrary function $h$ obeying the Laplace equation on $S^3$. We find the bosonic field $B$ which depends on the components of nonlinear supermultiplet and transforms as a full time derivative under N=4 supersymmetry. The most general interaction is generated just by a Fayet-Iliopoulos term built from this auxiliary component. Being transformed through a full time derivative under $N=4, d=1$ supersymmetry, this auxiliary component $B$ may be dualized into a fourth scalar field giving rise to a four dimensional $N=4, d=1$ sigma-model. We analyzed the geometry in the bosonic sector and find that it is not a hyper-Kähler one. With a particular choice of the target space metric $g$ the geometry in the bosonic sector coincides with the one which appears in heterotic $(4,0)$ sigma-model in $d=2$.
description: 9 pages, LaTeX file, PACS: 11.30.Pb, 03.65.-w
Anticancer Applications of Mesoporous Silica Nanoparticles
Creators: name: Mladenović, Minja
name: Mundžić, Mirjana
name: Pavlović, Aleksandra
name: Knežević, Nikola
Publisher: name: Zenodo
Year: 2021
Subjects: Mesoporous silica nanoparticles (MSNs)
nanocarriers
drug delivery
targeted therapy
on-demand release

description: The capabilities in applying mesoporous silica nanoparticles (MSN) for the construction of different types of nanosystems for simultaneous cancer therapy and diagnostics (theranostics) are widely known in the scientific literature. Their specific characteristics, such as high surface area (ca. 1000 m2/g), well-structured porosity, and versatile surface-functionalization possibilities allow devising a plethora of multifunctional nanostructures. In this context, our research team works on the synthesis of MSNs of different structures and their surface modification toward enabling active cancer-targeting. These MSNs are loaded with different cargo molecules which can serve different purposes, such as cancer treatment, imaging, or sensing cancer-specific environment and biomolecules. The process of cargo release can be also governed by employing externally applicable stimuli (e.g. light irradiation, magnetic field), or upon exposure to intratumoral conditions such as weakly acidic environment, the elevated concentration of glutathione, or in the presence of other cancer biomarkers. The control over this process allows the application of MSNs as unique facilitators in cancer therapy, imaging and sensing, with substantial benefits for enhancing the efficacy and precision of cancer treatment or for early cancer diagnosis.
description: Acknowledgments: The authors acknowledge financial support of the Science Fund of the Republic of Serbia (PROMIS Grant No. 6060755) and the European Union's Horizon 2020 research and innovation programme (Grant agreement No. 952259).
Exciton-exciton scattering: Composite boson versus elementary boson
Creators: name: Combescot, M.
name: Betbeder-Matibet, O.
name: Combescot, R.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: This paper introduces a new quantum object, the ``coboson'', for composite particles, like the excitons, which are made of two fermions. Although commonly dealed with as elementary bosons, these composite bosons -- ``cobosons'' in short -- differ from them due to their composite nature which makes the handling of their many-body effects quite different from the existing treatments valid for elementary bosons. Due to this composite nature, it is not possible to correctly describe the interaction between cobosons as a potential $V$. Consequently, the standard Fermi golden rule, written in terms of $V$, cannot be used to obtain the transition rates between exciton states. Through an unconventional expression for this Fermi golden rule, which is here given in terms of the Hamiltonian only, we here give a detailed calculation of the time evolution of two excitons. We compare the results of this exact approach with the ones obtained by using an effective bosonic exciton Hamiltonian. We show that the relation between the inverse lifetime and the sum of transition rates for elementary bosons differs from the one of composite bosons by a factor of 1/2, whatever the mapping from composite bosons to elementary bosons is. The present paper thus constitutes a strong mathematical proof that, in spite of a widely spread belief, we cannot forget the composite nature of these cobosons, even in the extremely low density limit of just two excitons. This paper also shows the (unexpected) cancellation, in the Born approximation, of the two-exciton transition rate for a finite value of the momentum transfer.
Automatic Differentiation With Higher Infinitesimals, or Computational Smooth Infinitesimal Analysis in Weil Algebra
Creators: name: Ishii, Hiromi
Publisher: name: arXiv
Year: 2021
Subjects: subject: Symbolic Computation (cs.SC)
subject: Mathematical Software (cs.MS)
subject: Numerical Analysis (math.NA)
subject: Category Theory (math.CT)
subject: Differential Geometry (math.DG)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: We propose an algorithm to compute the $C^\infty$-ring structure of arbitrary Weil algebra. It allows us to do some analysis with higher infinitesimals numerically and symbolically. To that end, we first give a brief description of the (Forward-mode) automatic differentiation (AD) in terms of $C^\infty$-rings. The notion of a $C^\infty$-ring was introduced by Lawvere and used as the fundamental building block of smooth infinitesimal analysis and synthetic differential geometry. We argue that interpreting AD in terms of $C^\infty$-rings gives us a unifying theoretical framework and modular ways to express multivariate partial derivatives. In particular, we can "package" higher-order Forward-mode AD as a Weil algebra, and take tensor products to compose them to achieve multivariate higher-order AD. The algorithms in the present paper can also be used for a pedagogical purpose in learning and studying smooth infinitesimal analysis as well.
description: to appear in Computer Algebra in Scientific Computing 2021
Finding Signs of Life in Transit: High-resolution Transmission Spectra of Earth-like Planets around FGKM Host Stars
Creators: name: Kaltenegger, Lisa
name: Lin, Zifan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Thousands of transiting exoplanets have already been detected orbiting a wide range of host stars, including the first planets that could potentially be similar to Earth. The upcoming Extremely Large Telescopes and the James Webb Space Telescope will enable the first searches for signatures of life in transiting exoplanet atmospheres. Here, we quantify the strength of spectral features in transit that could indicate a biosphere similar to the modern Earth on exoplanets orbiting a wide grid of host stars (F0 to M8) with effective temperatures between 2,500 and 7,000K: transit depths vary between about 6,000ppm (M8 host) to 30 ppm (F0 host) due to the different sizes of the host stars. CO2 possesses the strongest spectral features in transit between 0.4 and 20microns. The atmospheric biosignature pairs O2+CH4 and O3+CH4 - which identify Earth as a living planet - are most prominent for Sun-like and cooler host stars in transit spectra of modern Earth analogs. Assessing biosignatures and water on such planets orbiting hotter stars than the Sun will be extremely challenging even for high-resolution observations. All high-resolution transit spectra and model profiles are available online: they provide a tool for observers to prioritize exoplanets for transmission spectroscopy, test atmospheric retrieval algorithms, and optimize observing strategies to find life in the cosmos. In the search for life in the cosmos, transiting planets provide the first opportunity to discover whether or not we are alone, with this database as one of the keys to optimize the search strategies.
description: ApJL in press, 8 pages, 5 figures
Employment and Earnings in Nonmetro Industry, 1979-86
Creators: name: Majchrowicz, T. Alexander
name: Ghelfi, Linda M.
name: Majchrowicz, T. Alexander
name: Ghelfi, Linda M.
Publisher: name: Unknown
Year: 1988
Subjects: Financial Economics
Labor and Human Capital

description: Employment and earnings in nonmetropolitan (nonmetro) industries declined more during bad times and expanded less in good times than in metropolitan (metro) industries in 1979-86. Employment fell 0.5 percentage point a year in nonmetro areas during the 1979-82 recession, but rose each year in metro areas by 0.5 percentage point. Overall, real earnings declined during the recession, but dropped much faster in nonmetro industries: 3.5 percent a year in nonmetro industries compared with 0.9 percent a year in metro industries. The Midwest was hit hardest. Nonmetro industries improved only half as fast as metro industries during the 1982-86 recovery.
Pion-to-photon transition distribution amplitudes in the non-local chiral quark model
Creators: name: Kotko, Piotr
name: Praszalowicz, Michal
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We apply the non-local chiral quark model to study vector and axial pion-to-photon transition amplitudes that are needed as a nonperturbative input to estimate the cross section of pion annihilation into the real and virtual photon. We use a simple form of the non-locality that allows to perform all calculations in the Minkowski space and guaranties polynomiality of the TDA's. We note only residual dependence on the precise form of the cut-off function, however vector TDA that is symmetric in skewedness parameter in the local quark model is no longer symmetric in the non-local case. We calculate also the transition form-factors and compare them with existing experimental parametrizations.
description: 29 pages, 8 figures. Version published in Acta Physica Polonica B. Section devoted to semi-local model was erased
Spin texture in a bilayer high-temperature cuprate superconductor
Creators: name: Lu, Xiancong
name: Sénéchal, David
Publisher: name: arXiv
Year: 2021
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We investigate the possibility of spin texture in the bilayer cuprate superconductor $\rm Bi_2Sr_2CaCu_2O_{8+δ}$ using cluster dynamical mean field theory (CDMFT). The one-band Hubbard model with a small interlayer hopping and a Rashba spin-orbit coupling is used to describe the material. The $d$-wave order parameter is not much affected by the presence of the Rashba coupling, but a small triplet component appears. We find a spin texture circulating in the same direction around $\mathbf{k}=(0,0)$ and $\mathbf{k}=(π,π)$ and stable against the superconducting phase. The amplitude of the spin structure, however, is strongly affected by the pseudogap phenomenon, more so than the spectral function itself.
description: 5 pages, 4 figures
Μελέτη δημιουργίας και χαρακτηριστικών του δικτύου αναφοράς των πατεντών
Creators: name: Αγγέλου, Κωνσταντίνος Δημητρίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2017
Subjects: Δίκτυο-Αναφορά
Πατέντα
Network-Citation
Patent

description: Ο σκοπός της εργασίας αυτής είναι η μελέτη της δημιουργίας και των χαρακτηριστικών του δικτύου αναφοράς των πατεντών. Τα δεδομένα τα παρείχε ο Οργανισμός Οικονομικής Συνεργασίας και Ανάπτυξης και περιλαμβάνει πατέντες των European Patent Office και Patent Co-operation Treaty από το 1978 μέχρι το 2016. Αρχικά, υπάρχει μια θεωρητική εισαγωγή στα δίκτυα, τις ιδιότητες και τα χαρακτηριστικά τους καθώς επίσης και στην θεωρία της διήθησης. Στη συνέχεια, αναγνωρίζονται τα βασικά χαρακτηριστικά του δικτύου αναφοράς των πατεντών και εφαρμόζεται η μέθοδος k-shell decomposition για την εύρεση του πυρήνα του δικτύου, δηλαδή των πιο σημαντικών πατεντών για την σταθερότητα του δικτύου. Το αποτέλεσμα αυτής ήταν μη αναμενόμενο αφού βρέθηκε πως οι πατέντες με τις περισσότερες αναφορές δεν βρίσκονται στον πυρήνα. Τέλος, εφαρμόζεται και η θεωρία της διήθησης για την εύρεση του χρονικού διαστήματος που απαιτείται για την δημιουργία του μεγαλύτερου συγκροτήματος πατεντών, τόσο από την αρχή των δεδομένων όσο και από διάφορες ημερομηνίες εκκίνησης σαν να μην υπάρχουν τα δεδομένα πριν από αυτές. Το αποτέλεσμα που προέκυψε είναι πως το διάστημα αυτό μειώνεται σταδιακά με την πάροδο των χρόνων.
description: The purpose of this thesis is to study the characteristics and dynamics of the patent citation network with data obtained from OECD. At first, some fundamentals of the graph theory and network science are presented such as the properties of a network, as well as the theory of percolation. Next, these properties are studied in the patent citation network. K-shell decomposition is also applied to determine the core of the network. As for the dynamics, the duration needed for the largest component to be formed is examined. Finally, there is also checked how many days need to pass from various starting dates, as if the data would start from later on, so that the giant cluster is formed, which resulted that the number of days needed is decreasing throughout the years.
ANOVA for diffusions and Itô processes
Creators: name: Mykland, Per Aslak
name: Zhang, Lan
Publisher: name: arXiv
Year: 2006
Subjects: subject: Statistics Theory (math.ST)
subject: Statistical Finance (q-fin.ST)
subject: FOS: Mathematics
subject: FOS: Economics and business
subject: 60G44, 62M09, 62M10, 91B28 (Primary) 60G42, 62G20, 62P20, 91B84 (Secondary)

description: Itô processes are the most common form of continuous semimartingales, and include diffusion processes. This paper is concerned with the nonparametric regression relationship between two such Itô processes. We are interested in the quadratic variation (integrated volatility) of the residual in this regression, over a unit of time (such as a day). A main conceptual finding is that this quadratic variation can be estimated almost as if the residual process were observed, the difference being that there is also a bias which is of the same asymptotic order as the mixed normal error term. The proposed methodology, ``ANOVA for diffusions and Itô processes,'' can be used to measure the statistical quality of a parametric model and, nonparametrically, the appropriateness of a one-regressor model in general. On the other hand, it also helps quantify and characterize the trading (hedging) error in the case of financial applications.
description: Published at http://dx.doi.org/10.1214/009053606000000452 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Enhancement of wave transmissions in multiple radiative and convective zones
Creators: name: Cai, Tao
name: Yu, Cong
name: Wei, Xing
Publisher: name: arXiv
Year: 2021
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Geophysics (physics.geo-ph)
subject: FOS: Physical sciences

description: In this paper, we study wave transmission in a rotating fluid with multiple alternating convectively stable and unstable layers. We have discussed wave transmissions in two different circumstances: cases where the wave is propagative in each layer and cases where wave tunneling occurs. We find that efficient wave transmission can be achieved by `resonant propagation' or `resonant tunneling', even when stable layers are strongly stratified, and we call this phenomenon `enhanced wave transmission'. Enhanced wave transmission only occurs when the total number of layers is odd (embedding stable layers are alternatingly embedded within clamping convective layers, or vise versa). For wave propagation, the occurrence of enhanced wave transmission requires that clamping layers have similar properties, the thickness of each clamping layer is close to a multiple of the half wavelength of the corresponding propagative wave, and the total thickness of embedded layers is close to a multiple of the half wavelength of the corresponding propagating wave (resonant propagation). For wave tunneling, we have considered two cases: tunneling of gravity waves and tunneling of inertial waves. In both cases, efficient tunneling requires that clamping layers have similar properties, the thickness of each embedded layer is much smaller than the corresponding e-folding decay distance, and the thickness of each clamping layer is close to a multiple-and-a-half of half wavelength (resonant tunneling).
description: accepted to J. Fluid Mech
Λύση σύμβασης εμπορικής αντιπροσωπείας - Αποζημίωση πελατείας
Creators: name: Λαζαρίδου, Σοφία Σάββα
Publisher: name: Aristotle University of Thessaloniki
Year: 2017
Subjects: Εμπορική αντιπροσωπεία
Αποζημίωση
Πελατεία
Commercial agency
Compensation
Clientele

description: Σκοπός της διπλωματικής εργασίας είναι, μέσω της διερεύνησης της θεωρίας και της νομολογίας, η προσέγγιση του θεσμού της εμπορικής αντιπροσωπείας, σύμβασης που στην ελληνική έννομη τάξη διέπεται από το Π.Δ. 219/1991, σε θέματα αναφορικά με τη λύση της και ιδίως με την αποζημίωση πελατείας, αξίωση που το δίκαιο «απονέμει» στον εμπορικό αντιπρόσωπο. Στο Πρώτο Κεφάλαιο λοιπόν κάνουμε ανάλυση της σύμβασης εμπορικής αντιπροσωπείας και του εμπορικού αντιπροσώπου. Στο Δεύτερο Κεφάλαιο επιχειρούμε μία πρώτη προσέγγιση του θεσμού της αποζημίωσης πελατείας. Στο Τρίτο Κεφάλαιο, το οποίο χωρίζεται σε δύο επιμέρους παραγράφους, αναλύουμε πλέον τις προϋποθέσεις γεννήσεως της αξίωσης για αποζημίωση πελατείας. Στο Τέταρτο Κεφάλαιο, προσεγγίζουμε το θέμα του προσδιορισμού του ύψους της αποζημίωσης πελατείας καθώς και του τρόπου υπολογισμού της, όπως αυτός προτείνεται από την κρατούσα στη θεωρία άποψη. Στο Πέμπτο Κεφάλαιο αναλύουμε τους λόγους οι οποίοι συνεπάγονται την απώλεια της περί ης ο λόγος αποζημίωσης και τέλος, στο Έκτο Κεφάλαιο αναλύουμε την προβληματική αναφορικά με τη δυνατότητα της αναλογικής εφαρμογής του Π.Δ. 219/1991 και σε λοιπές διαμεσολαβητικές στο εμπόριο συμβάσεις.
description: The aim of the dissertation is the approach, by exploring theory and case law, of the institution of commercial agency, contract that in Greek legal system is governed by the P.D. 219/1991, on issues regarding the vitiation of this contract and the compensation due to the loss of clientele particularly, claim that legislation administers to the commercial agent. So, in Chapter One we analyze the contract of commercial agency and the commercial agent. In Chapter Two we attempt a first approach to the institution of compensation due to the loss of clientele. In the Third Chapter, which is divided into two separate sections, we analyze the conditions of «birth» of the claim for compensation due to the loss of clientele. In Chapter Four we approach the question of determining the level of this compensation and the means of calculating it, as the prevailing academic view suggests. In Chapter Five we analyze the reasons that lead to the loss of this compensation and last but not least, in Chapter Six we analyze the question with regard to the possibility of applying P.D. 219/1991 to other mediating commercial contracts, proportionally.
A (p,q)-deformed Landau problem in a spherical harmonic well: spectrum and noncommuting coordinates
Creators: name: Geloun, Joseph Ben
name: Govaerts, Jan
name: Hounkonnou, M. Norbert
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: A (p,q)-deformation of the Landau problem in a spherically symmetric harmonic potential is considered. The quantum spectrum as well as space noncommutativity are established, whether for the full Landau problem or its quantum Hall projections. The well known noncommutative geometry in each Landau level is recovered in the appropriate limit p,q=1. However, a novel noncommutative algebra for space coordinates is obtained in the (p,q)-deformed case, which could also be of interest to collective phenomena in condensed matter systems.
description: 9 pages, no figures; updated references
Mean-field caging in a random Lorentz gas
Creators: name: Biroli, Giulio
name: Charbonneau, Patrick
name: Hu, Yi
name: Ikeda, Harukuni
name: Szamel, Grzegorz
name: Zamponi, Francesco
Publisher: name: arXiv
Year: 2021
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The random Lorentz gas (RLG) is a minimal model of both percolation and glassiness, which leads to a paradox in the infinite-dimensional, $d\rightarrow\infty$ limit: the localization transition is then expected to be continuous for the former and discontinuous for the latter. As a putative resolution, we have recently suggested that as $d$ increases the behavior of the RLG converges to the glassy description, and that percolation physics is recovered thanks to finite-$d$ perturbative and non-perturbative (instantonic) corrections [Biroli et al. arXiv:2003.11179]. Here, we expand on the $d\rightarrow\infty$ physics by considering a simpler static solution as well as the dynamical solution of the RLG. Comparing the $1/d$ correction of this solution with numerical results reveals that even perturbative corrections fall out of reach of existing theoretical descriptions. Comparing the dynamical solution with the mode-coupling theory (MCT) results further reveals that although key quantitative features of MCT are far off the mark, it does properly capture the discontinuous nature of the $d\rightarrow\infty$ RLG. These insights help chart a path toward a complete description of finite-dimensional glasses.
description: 12 pages, 2 figures
Recent Developments at the Farm Credit System
Creators: name: Hughes, Merritt R.
name: Hughes, Merritt R.
Publisher: name: Unknown
Year: 1989
Subjects: Agricultural and Food Policy
Agricultural Finance

description: Rapid decreases in the number of Farm Credit System (PCS) loans to farmers during the 1980's severely strained the system. One strain on FCS income was the buildup of its allowance for loan losses. Another strain was on net interest income, which declined due to reduced volume of assets, as well as increased interest rates on debt. Legislation in 1987 reorganized the FCS, provided for up to $4 billion in assistance, and established new FCS institutions. FCS has now slowed the decline in its loan volume and improved its returns. It still faces a long road to complete recovery, with much of the cost of consolidating institutions, bailing out failing institutions, and restructuring loans still ahead.
Gauge-natural parameterized variational problems, vakonomic field theories and relativistic hydrodynamics of a charged fluid
Creators: name: Bibbona, Enrico
name: Fatibene, Lorenzo
name: Francaviglia, Mauro
Publisher: name: arXiv
Year: 2006
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 70S05, 58E50, 83C40, 76M30

description: Variational principles for field theories where variations of fields are restricted along a parametrization are considered. In particular, gauge-natural parametrized variational problems are defined as those in which both the Lagrangian and the parametrization are gauge covariant and some further conditions is satisfied in order to formulate a Nöther theorem that links horizontal and gauge symmetries to the relative conservation laws (generalizing what Fern{á}ndez, Garc{\'ı}a and Rodrigo did in some recent papers). The case of vakonomic constraints in field theory is also studied within the framework of parametrized variational problems, defining and comparing two different concepts of criticality of a section, one arising directly from the vakonomic schema, the other making use of an adapted parametrization. The general theory is then applied to the case of hydrodynamics of a charged fluid coupled with its gravitational and electromagnetic field. A variational formulation including conserved currents and superpotentials is given that turns out to be computationally much easier than the standard one.
Emergence of Dirac Composite Fermions: Dipole Picture
Creators: name: Ji, Guangyue
name: Shi, Junren
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Composite fermions (CFs) are the particles underlying the novel phenomena observed in partially filled Landau levels. Both microscopic wave functions and semi-classical dynamics suggest that a CF is a dipole consisting of an electron and a double $2h/e$ quantum vortex, and its motion is subject to a Berry curvature that is uniformly distributed in the momentum space. Based on the picture, we study the electromagnetic response of composite fermions. We find that the response in the long-wavelength limit has a form identical to that of the Dirac CF theory. To obtain the result, we show that the Berry curvature contributes a half-quantized Hall conductance which, notably, is independent of the filling factor of a Landau level and not altered by the presence of impurities. The latter is because CFs undergo no side-jumps when scattered by quenched impurities in a Landau-level with the particle-hole symmetry. The remainder of the response is from an effective system that has the same Fermi wavevector, effective density, Berry phase, and therefore long-wavelength response to electromagnetic fields as a Dirac CF system. By interpreting the half-quantized Hall conductance as a contribution from a redefined vacuum, we can explicitly show the emergence of a Dirac CF effective description from the dipole picture. We further determine corrections due to electric quadrupoles and magnetic moments of CFs and show deviations from the Dirac CF theory when moving away from the long wavelength limit.
description: 16 pages, 2 figures, 1 table
Bergmann-Thomson energy-momentum complex for solutions more general than the Kerr-Schild class
Creators: name: Xulu, S. S.
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Astrophysics (astro-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In a very well-known paper, Virbhadra's research group proved that the Weinberg, Papapetrou, Landau and Lifshitz, and Einstein energy-momentum complexes ``coincide'' for all metrics of Kerr-Schild class. A few years later, Virbhadra clarified that this ``coincidence'' in fact holds for metrics more general than the Kerr-Schild class. In the present paper, this study is extended for the Bergmann-Thomson complex and it is proved that this complex also ``coincides'' with those complexes for a more general than the Kerr-Schild class metric.
description: RevTex, 12 pages
Self-repelling random walk with directed edges on Z
Creators: name: Toth, Balint
name: Veto, Balint
Publisher: name: arXiv
Year: 2008
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 82C41

description: We consider a variant of self-repelling random walk on the integer lattice Z where the self-repellence is defined in terms of the local time on oriented edges. The long-time asymptotic scaling of this walk is surprisingly different from the asymptotics of the similar process with self-repellence defined in terms of local time on unoriented edges. We prove limit theorems for the local time process and for the position of the random walker. The main ingredient is a Ray-Knight-type of approach. At the end of the paper, we also present some computer simulations which show the strange scaling behaviour of the walk considered.
description: 19 pages, 4 figures