cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Enhanced motility of a microswimmer in rigid and elastic confinement
Creators: name: Ledesma-Aguilar, Rodrigo
name: Yeomans, Julia M.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Biological Physics (physics.bio-ph)
subject: FOS: Physical sciences

description: We analyse the effect of confining rigid and elastic boundaries on the motility of a model dipolar microswimmer. Flexible boundaries are deformed by the velocity field of the swimmer in such a way that the motility of both extensile and contractile swimmers is enhanced. The magnitude of the increase in swimming velocity is controlled by the ratio of the swimmer-advection and elastic timescales, and the dipole moment of the swimmer. We explain our results by considering swimming between inclined rigid boundaries.
description: 5 pages, 3 figures. Physical Review Letters - accepted
Unsupervised Galaxy Morphological Visual Representation with Deep Contrastive Learning
Creators: name: Wei, Shoulin
name: Li, Yadi
name: Lu, Wei
name: Li, Nan
name: Liang, Bo
name: Dai, Wei
name: Zhang, Zhijian
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Galaxy morphology reflects structural properties which contribute to understand the formation and evolution of galaxies. Deep convolutional networks have proven to be very successful in learning hidden features that allow for unprecedented performance on galaxy morphological classification. Such networks mostly follow the supervised learning paradigm which requires sufficient labelled data for training. However, it is an expensive and complicated process of labeling for million galaxies, particularly for the forthcoming survey projects. In this paper, we present an approach based on contrastive learning with aim for learning galaxy morphological visual representation using only unlabeled data. Considering the properties of low semantic information and contour dominated of galaxy image, the feature extraction layer of the proposed method incorporates vision transformers and convolutional network to provide rich semantic representation via the fusion of the multi-hierarchy features. We train and test our method on 3 classifications of datasets from Galaxy Zoo 2 and SDSS-DR17, and 4 classifications from Galaxy Zoo DECaLS. The testing accuracy achieves 94.7%, 96.5% and 89.9% respectively. The experiment of cross validation demonstrates our model possesses transfer and generalization ability when applied to the new datasets. The code that reveals our proposed method and pretrained models are publicly available and can be easily adapted to new surveys.
description: 21 pages, 16 figures
Relating quasi-stationary one zone emission models to expanding relativistic shocks
Creators: name: Derishev, Evgeny
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: For an expanding spherical relativistic shock, we derive relations between the parameters of downstream emitting zone and the quantities measured by a distant observer. These relations are formulated in terms of dimensionless effective coefficients combined with self-evident dimensional estimates. Our calculations take into account evolution of the shock's Lorentz factor, geometrical delay due to the shock's front curvature, and angular dependence of Lorentz boost for frequency and brightness. The relations are designed primarily for application in Gamma-Ray Burst afterglow studies, although they may have a broader use.
description: 8 pages, 4 figures
TRIM Simulations Tool for $μ^+$ Stopping Fraction in Hydrostatic Pressure Cells
Creators: name: Elson, Frank
name: Das, Debarchan
name: Simutis, Gediminas
name: Forslund, Ola Kenji
name: Miniotaite, Ugne
name: Palm, Rasmus
name: Sassa, Yasmine
name: Weissenrieder, Jonas
name: Månsson, Martin
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computational Physics (physics.comp-ph)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: For quantum systems or materials, a common procedure for probing their behaviour is to tune electronic/magnetic properties using external parameters, e.g. temperature, magnetic field or pressure. Pressure application as an external stimuli is a widely used tool, where the sample in question is inserted into a pressure cell providing a hydrostatic pressure condition. Such device causes some practical problems when using in Muon Spin Rotation/Relaxation ($μ^+$SR) experiments as a large proportion of the muons will be implanted in the pressure cell rather than in the sample, resulting in a higher background signal. This issue gets further amplified when the temperature dependent response from the sample is much smaller than that of the pressure cell,which may cause the sample response to be lost in the background and cause difficulties in aligning the sample within the beam. To tackle this issue, we have used pySRIM to construct a practical and helpful simulation tool for calculating muon stopping fractions, specifically for the pressure cell setup at the $μ$E1 beamline using the GPD spectrometer at the Paul Scherrer Institute, with the use of TRIM simulations. The program is used to estimate the number of muon stopping in both the sample and the pressure cell at a given momentum. The simulation tool is programmed into a GUI, making it accessible to user to approximate prior to their experiments at GPD what fractions will belong to the sample and the pressure cell in their fitting procedure.
description: 8 Pages, 3 Figures, Conference proceedings for 15th international conference on muon spin rotation, relaxation and resonance
Power of the interactive proof systems with verifiers modeled by semi-quantum two-way finite automata
Creators: name: Zheng, Shenggen
name: Qiu, Daowen
name: Gruska, Jozef
Publisher: name: arXiv
Year: 2013
Subjects: subject: Computational Complexity (cs.CC)
subject: Cryptography and Security (cs.CR)
subject: Quantum Physics (quant-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences
subject: F.1.1

description: In this paper we explore the power of AM for the case that verifiers are {\em two-way finite automata with quantum and classical states} (2QCFA)--introduced by Ambainis and Watrous in 2002--and the communications are classical. It is of interest to consider AM with such "semi-quantum" verifiers because they use only limited quantum resources. Our main result is that such Quantum Arthur-Merlin proof systems (QAM(2QCFA)) with polynomial expected running time are more powerful than in the case verifiers are two-way probabilistic finite automata (AM(2PFA)) with polynomial expected running time. Moreover, we prove that there is a language which can be recognized by an exponential expected running time QAM(2QCFA), but can not be recognized by any AM(2PFA), and that the NP-complete language $L_{knapsack}$ can also be recognized by a QAM(2QCFA) working only on quantum pure states using unitary operators.
description: 26 pages, 5 figures, some references have been added, and comments are welcome
Inter-Cell Network Slicing With Transfer Learning Empowered Multi-Agent Deep Reinforcement Learning
Creators: name: Hu, Tianlun
name: Liao, Qi
name: Liu, Qiang
name: Carle, Georg
Publisher: name: arXiv
Year: 2023
Subjects: subject: Networking and Internet Architecture (cs.NI)
subject: Machine Learning (cs.LG)
subject: Multiagent Systems (cs.MA)
subject: FOS: Computer and information sciences

description: Network slicing enables operators to efficiently support diverse applications on a common physical infrastructure. The ever-increasing densification of network deployment leads to complex and non-trivial inter-cell interference, which requires more than inaccurate analytic models to dynamically optimize resource management for network slices. In this paper, we develop a DIRP algorithm with multiple deep reinforcement learning (DRL) agents to cooperatively optimize resource partition in individual cells to fulfill the requirements of each slice, based on two alternative reward functions. Nevertheless, existing DRL approaches usually tie the pretrained model parameters to specific network environments with poor transferability, which raises practical deployment concerns in large-scale mobile networks. Hence, we design a novel transfer learning-aided DIRP (TL-DIRP) algorithm to ease the transfer of DIRP agents across different network environments in terms of sample efficiency, model reproducibility, and algorithm scalability. The TL-DIRP algorithm first centrally trains a generalized model and then transfers the "generalist" to each local agent as "specialist" with distributed finetuning and execution. TL-DIRP consists of two steps: 1) centralized training of a generalized distributed model, 2) transferring the "generalist" to each "specialist" with distributed finetuning and execution. The numerical results show that not only DIRP outperforms existing baseline approaches in terms of faster convergence and higher reward, but more importantly, TL-DIRP significantly improves the service performance, with reduced exploration cost, accelerated convergence rate, and enhanced model reproducibility. As compared to a traffic-aware baseline, TL-DIRP provides about 15% less violation ratio of the quality of service (QoS) for the worst slice service and 8.8% less violation on the average service QoS.
description: 14 pages, 14 figures, IEEE Open Journal of the Communications Society
Chemo-dynamical substructure in the M31 inner halo globular clusters: Further evidence for a recent accretion event
Creators: name: Lewis, Geraint F.
name: Brewer, Brendon J.
name: Mackey, Dougal
name: Ferguson, Annette M. N.
name: Yuan
name: Li
name: Adams, Tim
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Based upon a metallicity selection, we identify a significant sub-population of the inner halo globular clusters in the Andromeda Galaxy which we name the Dulais Structure. It is distinguished as a co-rotating group of 10-20 globular clusters which appear to be kinematically distinct from, and on average more metal-poor than, the majority of the inner halo population. Intriguingly, the orbital axis of this Dulais Structure is closely aligned with that of the younger accretion event recently identified using a sub-population of globular clusters in the outer halo of Andromeda, and this is strongly suggestive of a causal relationship between the two. If this connection is confirmed, a natural explanation for the kinematics of the globular clusters in the Dulais Structure is that they trace the accretion of a substantial progenitor (~10^11 Msun) into the halo of Andromeda during the last few billion years, that may have occurred as part of a larger group infall.
description: 10 pages, 7 figures - accepted for publication in MNRAS
ПЕРЕРАБОТКА ПИРОЛИЗНОГО ДИСТИЛЯТА
Creators: name: Жўраева, Л.Р.
name: Гиясова, Г.М.
name: Холбоев, Р.Ж.
Publisher: name: Zenodo
Year: 2023

description: Бензол – важнейшее сырье нефтехимической промышленности, на основе которого производят крупнотоннажные продукты органического синтеза. По данным Росстата, объем производства бензола (в том числе из продуктов пиролиза, нефтяного) составил 1200 тыс. тонн.
The Stability of Delaunay Triangulations
Creators: name: Boissonnat, Jean-Daniel
name: Dyer, Ramsay
name: Ghosh, Arijit
Publisher: name: arXiv
Year: 2013
Subjects: subject: Computational Geometry (cs.CG)
subject: FOS: Computer and information sciences

description: We introduce a parametrized notion of genericity for Delaunay triangulations which, in particular, implies that the Delaunay simplices of $δ$-generic point sets are thick. Equipped with this notion, we study the stability of Delaunay triangulations under perturbations of the metric and of the vertex positions. We quantify the magnitude of the perturbations under which the Delaunay triangulation remains unchanged.
description: Displayed expressions in the statements of Thm 3.14 and Cor 4.18 are missing a factor of the dimension (m) in the denominator of the version published in IJCGA: it is corrected here
Spin-dependent sub-GeV Inelastic Dark Matter-electron scattering and Migdal effect: (I). Velocity Independent Operator
Creators: name: Li, Jiwei
name: Su, Liangliang
name: Wu, Lei
name: Zhu, Bin
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The ionization signal provide an important avenue of detecting light dark matter. In this work, we consider the sub-GeV inelastic dark matter and use the non-relativistic effective field theory (NR-EFT) to derive the constraints on the spin-dependent DM-electron scattering and DM-nucleus Migdal scattering. Since the recoil electron spectrum of sub-GeV DM is sensitive to tails of galactic DM velocity distributions, we also compare the bounds on corresponding scattering cross sections in Tsallis, Empirical and standard halo models. With the XENON1T data, we find that the exclusion limits of the DM-proton/neutron and DM-electron scattering cross sections for exothermic inelastic DM are much stronger that those for the endothermic inelastic DM. Each limits of the endothermic inelastic DM can differ by an order of magnitude at most in three considered DM velocity distributions.
description: 37 pages, 7 figures, discussions and references added, version published in JCAP
Faculty development for Columbia University School of Social Work’s Online Campus: A Brief Overview
Creators: name: Marquart, Matthea S.
name: Garay, Kristin
name: Baez, Johanna C.
Publisher: name: Columbia University
Year: 2020
Subjects: Web-based instruction
Distance education
Social work education
Universities and colleges--Faculty--Training of

description: These are the slides from a presentation by Columbia University School of Social Work’s Online Campus admin team for a meeting of the Digital Community @ Columbia (DCC), to share an overview of the faculty development opportunities the admin team provides for online faculty. The faculty development is open to all CSSW Online Campus community members, and is scheduled to accommodate the availability of adjunct faculty. Some of the resources are available publicly, for any faculty anywhere.
A generalization of Schmidt number for multipartite states
Creators: name: Guo, Yu
name: Fan, Heng
Publisher: name: arXiv
Year: 2013
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The Schmidt number is of crucial importance in characterizing the bipartite pure states. We explore and propose here a generalization of Schmidt number for states in multipartite systems. It is shown to be entanglement monotonic and valid for both pure and mixed states. In addition, the corresponding generalization of multipartite Schmidt coefficients is introduced. Our approach is applicable for systems with arbitrary number of parties and for arbitrary dimensions.
description: 10pages, some minors are corrected
title: Ανάπτυξη χαμηλού κόστους τεχνολογίας για την προ-επεξεργασία των υγρών αποβλήτων ελαιοτριβείων (ΥΑΕ)
Creators: name: Καραϊσκος Λαμπρος
Publisher: name: Technical University of Crete
Year: 2016

description: Τα υγρά απόβλητα των ελαιουργείων (ΥΑΕ) παράγονται κατά την εξαγωγή του ελαιόλαδου από τα παραδοσιακά και τα φυγοκεντρικά ελαιοτριβεία τριών φάσεων και αποτελούν ένα σημαντικό και συνεχώς διογκούμενο περιβαλλοντικό πρόβλημα λόγω της μεγάλης ποσότητάς τους, του υψηλού οργανικού ρυπαντικού τους φορτίου και των ιδιαίτερων συστατικών τους (φαινολικές ενώσεις) που είναι δύσκολα αποδομήσιμα.
Το πρόβλημα που δημιουργείται από αυτά τα απόβλητα είναι εντονότερο στις Μεσογειακές χώρες όπου παράγεται το 97% της παγκόσμιας παραγωγής ελαιολάδου. Η μελέτη του προβλήματος καθώς και η αντιμετώπιση του είναι αλληλένδετα και οι λύσεις που χρησιμοποιούνται ποικίλουν όχι μόνο από χώρα σε χώρα αλλά και από περιοχή σε περιοχή. Στη χώρα μας η πιο κοινή μέθοδος διαχείρισης των ΥΑΕ είναι η διάθεσή τους σε εξατμισοδεξαμενές.
Ωστόσο, διάφορες μέθοδοι διαχείρισης έχουν προταθεί για την επεξεργασία των ΥΑΕ, συμπεριλαμβανομένων φυσικών, φυσικοχημικών, βιολογικών, θερμικών και συνδυασμό τους, όπως αραίωση, φυγοκέντρηση, επίπλευση, κροκίδωση/συσσωμάτωση, προσρόφηση, αναερόβια και αερόβια επεξεργασία, εξάτμιση-απόσταξη, καύση-πυρόλυση, κ.ά.
Από τα συστατικά των ΥΑΕ ιδιαίτερο ενδιαφέρον παρουσιάζουν οι φαινόλες, οι οποίες ως αντιοξειδωτικές ουσίες εμποδίζουν τη διάσπαση των λιπαρών οξέων και βοηθούν στη διατήρηση του λαδιού. Είναι όμως η κύρια ρυπαντική παράμετρος, η οποία ευθύνεται για τις σημαντικές περιβαλλοντικές επιπτώσεις των υγρών αποβλήτων των ελαιουργείων.
Επειδή τα υγρά απόβλητα περιέχουν φαινόλες, οξέα, μεταλλικά στοιχεία και οργανικές ενώσεις, η άμεση διάθεση αυτών των αποβλήτων στο έδαφος, επηρεάζει σημαντικά τις φυσικοχημικές (pH, αγωγιμότητα, συγκέντρωση αμμωνιακού, νιτρικού αζώτου και οργανικού άνθρακα) και βιολογικές (μικροβιακή δραστηριότητα) ιδιότητές του.
Στόχος της παρούσας διπλωματικής εργασίας είναι η ανάπτυξη μιας χαμηλού κόστους τεχνολογίας για την προ-επεξεργασία των υγρών αποβλήτων ελαιοτριβείων με χρήση κυρίως χαμηλού κόστους πρώτων υλών.
Deep Learning Methods for Retinal Blood Vessel Segmentation: Evaluation on Images with Retinopathy of Prematurity
Creators: name: Gojić, Gorana
name: Petrović, Veljko
name: Turović, Radovan
name: Dragan, Dinu
name: Oros, Ana
name: Gajić, Dušan
name: Horvat, Nebojša
Publisher: name: arXiv
Year: 2023
Subjects: subject: Image and Video Processing (eess.IV)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: Automatic blood vessel segmentation from retinal images plays an important role in the diagnosis of many systemic and eye diseases, including retinopathy of prematurity. Current state-of-the-art research in blood vessel segmentation from retinal images is based on convolutional neural networks. The solutions proposed so far are trained and tested on images from a few available retinal blood vessel segmentation datasets, which might limit their performance when given an image with retinopathy of prematurity signs. In this paper, we evaluate the performance of three high-performing convolutional neural networks for retinal blood vessel segmentation in the context of blood vessel segmentation on retinopathy of prematurity retinal images. The main motive behind the study is to test if existing public datasets suffice to develop a high-performing predictor that could assist an ophthalmologist in retinopathy of prematurity diagnosis. To do so, we create a dataset consisting solely of retinopathy of prematurity images with retinal blood vessel annotations manually labeled by two observers, where one is the ophthalmologist experienced in retinopathy of prematurity treatment. Experimental results show that all three solutions have difficulties in detecting the retinal blood vessels of infants due to a lower contrast compared to images from public datasets as demonstrated by a significant drop in classification sensitivity. All three solutions segment alongside retinal also choroidal blood vessels which are not used to diagnose retinopathy of prematurity, but instead represent noise and are confused with retinal blood vessels. By visual and numerical observations, we observe that existing solutions for retinal blood vessel segmentation need improvement toward more detailed datasets or deeper models in order to assist the ophthalmologist in retinopathy of prematurity diagnosis.
Das Weihwasser im heidnischen und christlichen Cultus, unter besonderer Berücksichtigung des germanischen Alterthums. Ein Beitrag zur vergleichenden Religionswissenschaft, von Heinr. Pfannenschmid, Hannover 1869
Creators: name: Otte, Heinrich
Publisher: name: Bonner Jahrbücher
Year: 2017

description: Rezension zu: Das Weihwasser im heidnischen und christlichen Cultus, unter besonderer Berücksichtigung des germanischen Alterthums. Ein Beitrag zur vergleichenden Religionswissenschaft. Von Dr. Heinr. Pfannenschmid. Mit 2 Holzschnitten. Hannover, Hahn’sche Hofbuchhandlung 1869. XIV und 231 S. 8.
description: Bonner Jahrbücher, Bd. 50/51 (1871): Jahrbücher des Vereins von Alterthumsfreunden im Rheinlande
The Many Faces of Fluctuation-Dissipation Relations Out of Equilibrium
Creators: name: Baldovin, Marco
name: Caprini, Lorenzo
name: Puglisi, Andrea
name: Sarracino, Alessandro
name: Vulpiani, Angelo
Publisher: name: arXiv
Year: 2022
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: In this paper, we offer to the reader an essential review of the theory of Fluctuation-Dissipation Relations (FDR), from the first formulations due to Einstein and Onsager, to the recent developments in the framework of stochastic thermodynamics of non-equilibrium system. We focus on two general approaches, somehow complementary, where out-of-equilibrium contributions to the FDR are expressed in terms of different quantities, related either to the stationary distribution or to the transition rates of the system. In particular, we discuss applications of the FDR in the general field of causation and inference, and in the contexts of non-equilibrium systems, such as spin models, granular media and active matter.
description: 29 pages, 3 figures, chapter in the book "Nonequilibrium Thermodynamics and Fluctuation Kinetics" (editors L\'eon Brenig, Nikolai Brilliantov, Mustapha Tlidi) Springer 2022
Singularity analysis via the iterated kernel method
Creators: name: Melczer, Stephen
name: Mishna, Marni
Publisher: name: arXiv
Year: 2013
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: In the quarter plane, five lattice path models with unit steps have resisted the otherwise general approach of Fayolle, Rachel, and Kurkova. Here we consider these five models, called the singular models, and prove that the generating functions marking the number of walks of a given length are not D-finite -- thus finishing the proof of a conjecture of Bousquet-Mélou and Mishna. Furthermore, we provide exact and asymptotic enumerative formulas for the number of such walks.
description: 23 pages, added new introduction, other clarifications and fixes
Deep Double Self-Expressive Subspace Clustering
Creators: name: Zhao, Ling
name: Ma, Yunpeng
name: Chen, Shanxiong
name: Zhou, Jun
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Deep subspace clustering based on auto-encoder has received wide attention. However, most subspace clustering based on auto-encoder does not utilize the structural information in the self-expressive coefficient matrix, which limits the clustering performance. In this paper, we propose a double self-expressive subspace clustering algorithm. The key idea of our solution is to view the self-expressive coefficient as a feature representation of the example to get another coefficient matrix. Then, we use the two coefficient matrices to construct the affinity matrix for spectral clustering. We find that it can reduce the subspace-preserving representation error and improve connectivity. To further enhance the clustering performance, we proposed a self-supervised module based on contrastive learning, which can further improve the performance of the trained network. Experiments on several benchmark datasets demonstrate that the proposed algorithm can achieve better clustering than state-of-the-art methods.
description: 5 pagees,4 figures,ICASSP2023, revised version
title: Επεξεργασία συνθετικών δεδομένων σεισμικής ανάκλασης για το ορυχείο της Μαυροπηγής Κοζάνης
Creators: name: Καζαντζιδης Δημητριος
Publisher: name: Technical University of Crete
Year: 2016

description: Ένα συνηθισμένο πρόβλημα που παρατηρείται στην περιοχή της Μαυροπηγής Κοζάνης σχετίζεται με την ευστάθεια των  πρανών εκμετάλλευσης, η οποία επηρεάζεται από τις γεωλογικές συνθήκες της περιοχής.
Το αντικείμενο της παρούσας διπλωματικής εργασίας είναι να ερευνηθεί με την προσομοίωση και την επεξεργασία δισδιάστατων συνθετικών δεδομένων, αν η μέθοδος της σεισμικής ανάκλασης μπορεί να δώσει ικανοποιητικά αποτελέσματα στην χαρτογράφηση της δομής του υπεδάφους,η οποία χαρακτηρίζεται από απότομες κλίσεις των παρειών του σχιστολιθικού υποβάθρου, στην περιοχή του λιγνιτωρυχείου της Μαυροπηγής Κοζάνης.Τα αποτελέσματα της προσομοίωσης, μπορούν χρησιμοποιηθούν στο βέλτιστο σχεδιασμό πραγματικού πειράματος σεισμικής ανάκλασης στην περιοχή μελέτης.
Η δημιουργία των συνθετικών σεισμικών δεδομένων πραγματοποιήθηκεκατά μήκος 2 γεωλογικών τομών, οι οποίες προέκυψαν από γεωτριτικά δεδομένα της ευρύτερης περιοχής μελέτης.Στο πλαίσιο της παρούσας διπλωματικής γίνεται αναφορά στη Γεωλογία της περιοχής μελέτης και ακολουθεί μια γενική αναφορά στη μέθοδο σεισμικής ανάκλασης.
Παρουσιάζεται αναλυτικά η διαδικασία δημιουργίας των συνθετικών δεδομένων, με την μέθοδο των πεπερασμένων διαφορών μέσω του προγράμματος Matlab και κατάλληλων αλγορίθμων οι οποίοι αναπτύχθηκαν στο Εργαστήριο Εφαρμοσμένης Γεωφυσικής του πολυτεχνείου Κρήτης.
Ακολουθεί η επεξεργασία των συνθετικών δεδομένων, όπου κύριος σκοπός των διαδικασιών αυτών είναι η αύξηση του λόγου του σήματος προς το θόρυβο και η βελτίωση της διακριτικής ικανότητας των δεδομένων.Η επεξεργασία περιλαμβάνει τις διαδικασίες της εισαγωγής τεχνητού θορύβου, της αναδιάταξης των δεδομένων σε καταγραφές κοινού ενδιάμεσου σημείου (CMP sorting), τον υπολογισμό της μέσης τετραγωνικής ταχύτητας, της  διόρθωσης της κανονικής χρονικής απόκλισης (NMO correction), της σεισμικής υπέρθεσης (stacking) και της σεισμικής χωροθέτησης (Migration). Για δημιουργία μίας καλύτερης απεικόνισης των τομών της σεισμικής υπέρθεσης και χωροθέτησης χρησιμοποιήθηκε και το πρόγραμμα Transform.
Από τα αποτελέσματα της παρούσας εργασίας προέκυψε ότι είναι δυνατή η χαρτογράφηση του σχιστολιθικού υποβάθρου στην περιοχή μελέτης με την χρήση της μεθόδου σεισμικής ανάκλασης και της μεθοδολογίας απόκτησης και επεξεργασίας των σεισμικών δεδομένων που αναπτύχθηκαν. Ωστόσο, θα πρέπει να σημειωθεί ότι κατέστη δυνατή η απεικόνιση μόνο των τμημάτων του υποβάθρου που είχαν ήπια κλίση, ενώ η χαρτογράφηση αυτών με μεγάλη κλίση, προέκυψε συμπερασματικά από την μορφολογία των απεικονισθέντων τμημάτων του υποβάθρου.
The Effect of the U.S.-China Trade War on U.S. Investment
Creators: name: Amiti, Mary
name: Kong, Sang Hoon
name: Weinstein, David E.
Publisher: name: Columbia University
Year: 2020
Subjects: Investments
Adjustment costs
Tariff
Commerce
Commercial policy

description: We develop a new method of quantifying the impact of policy announcements on investment rates that makes use of stock market data. By estimating the effect of U.S.-China tariff announcements on aggregate returns and the differential returns of firms exposed to China, we identify their effect on treated and untreated firms. We show theoretically and empirically that estimates of policy-induced stock-market declines imply lower returns to capital, which lowers investment rates. We estimate that the tariff actions through 2018 and 2019 will lower the investment growth rate of listed U.S. companies by 1.9 percentage points by the end of 2020.
Chaos and operator growth in 2d CFT
Creators: name: Khetrapal, Surbhi
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study the out-of-time-ordered correlator (OTOC) in a zero temperature two dimensional conformal field theory (CFT) under evolution by a Liouvillian composed of the Virasoro generators. A bound was conjectured in arXiv:1812.08657 on the growth of the OTOC set by the Krylov complexity which is a measure of operator growth. The latter grows as an exponential of time with exponent $2α$, which sets an upper bound on the Lyapunov exponent, $λ_L \leq 2α$. We find that for a two dimensional zero temperature CFT, the OTOC decays exponentially with a Lyapunov exponent which saturates this bound. We show that these Virasoro generators form the modular Hamiltonian of the CFT with half space traced out. Therefore, evolution by this modular Hamiltonian gives rise to thermal dynamics in a zero temperature CFT. Leveraging the thermal dynamics of the system, we derive this bound in a zero temperature CFT using the analyticity and boundedness properties of the OTOC.
description: 21 pages, version published in JHEP
Nonlinear chiral photocurrent in parity-violating magnetic Weyl semimetals
Creators: name: Heidari, Shiva
name: Asgari, Reza
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: The strong correlation between the non-trivial band topology and the magnetic texture makes magnetic Weyl semimetals excellent candidates for the manipulation and detection of magnetization dynamics. The parity violation together with the Pauli blocking cause only one Weyl node to contribute to the photocurrent response, which in turn affects the magnetic texture due to the spin transfer torque. Utilizing the Landau-Lifshitz-Gilbert equation and the spin-transfer torque in non-centrosymmetric Weyl magnets, we show that the chiral photocurrent rotates the magnetization from the easy c axis to the a or b axis, which leads to an exotic current next to the photocurrent response. The chiral photocurrent is calculated in the context of quantum kinetic theory and it has a strong resonance on the order of mA/W near the Weyl nodes, the magnitude of which is controlled by the momentum relaxation time. Remarkably, we study the influence of magnetic texture dynamics on the topological nonlinear photocurrent response, including shift and injection currents along with the new chiral photocurrent, and show that both the magnitude and the in-plane orientation of the chiral photocurrent are strongly correlated with the direction of the magnetic moments.
Some remarks on regular integers modulo $n$
Creators: name: Apostol, Brăduţ
name: Tóth, László
Publisher: name: arXiv
Year: 2013
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 11A25, 11B68, 11N37, 33B10, 33B15

description: An integer $k$ is called regular (mod $n$) if there exists an integer $x$ such that $k^2x\equiv k$ (mod $n$). This holds true if and only if $k$ possesses a weak order (mod $n$), i.e., there is an integer $m\ge 1$ such that $k^{m+1} \equiv k$ (mod $n$). Let $\varrho(n)$ denote the number of regular integers (mod $n$) in the set $\{1,2,\ldots,n\}$. This is an analogue of Euler's $ϕ$ function. We introduce the multidimensional generalization of $\varrho$, which is the analogue of Jordan's function. We establish identities for the power sums of regular integers (mod $n$) and for some other finite sums and products over regular integers (mod $n$), involving the Bernoulli polynomials, the Gamma function and the cyclotomic polynomials, among others. We also deduce an analogue of Menon's identity and investigate the maximal orders of certain related functions.
description: 18 pages, revised
Cosmological constraints on holographic dark energy models under the energy conditions
Creators: name: Zhang, Ming-Jian
name: Ma, Cong
name: Zhang, Zhi-Song
name: Zhai, Zhong-Xu
name: Zhang, Tong-Jie
Publisher: name: arXiv
Year: 2013
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We study the holographic and agegraphic dark energy models without interaction using the latest observational Hubble parameter data (OHD), the Union2.1 compilation of type Ia supernovae (SNIa), and the energy conditions. Scenarios of dark energy are distinguished by the cut-off of cosmic age, conformal time, and event horizon. The best-fit value of matter density for the three scenarios almost steadily located at $Ω_{m0}=0.26$ by the joint constraint. For the agegraphic models, they can be recovered to the standard cosmological model when the constant $c$ which presents the fraction of dark energy approaches to infinity. Absence of upper limit of $c$ by the joint constraint demonstrates the recovery possibility. Using the fitted result, we also reconstruct the current equation of state of dark energy at different scenarios, respectively. Employing the model criteria $χ^2_{\textrm{min}}/dof$, we find that conformal time model is the worst, but they can not be distinguished clearly. Comparing with the observational constraints, we find that SEC is fulfilled at redshift $0.2 \lesssim z \lesssim 0.3$ with $1σ$ confidence level. We also find that NEC gives a meaningful constraint for the event horizon cut-off model, especially compared with OHD only. We note that the energy condition maybe could play an important role in the interacting models because of different degeneracy between $Ω_m$ and constant $c$.
description: 8 pages, 4 figures, accepted for publication in PRD
Probing the Low-mass End of the Black Hole Mass Function via a Study of Faint Local Spiral Galaxies
Creators: name: Fusco, Michael S.
name: Davis, Benjamin L.
name: Kennefick, Julia
name: Kennefick, Daniel
name: Seigar, Marc S.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present an analysis of the pitch angle distribution function (PADF) for nearby galaxies and its resulting black hole mass function (BHMF) via the well-known relationship between pitch angle and black hole mass. Our sample consists of a subset of 74 spiral galaxies from the Carnegie-Irvine Galaxy Survey with absolute $B$-band magnitude $\mathfrak{M}_{B}>-19.12$ mag and luminosity distance $D_{\mathrm{L}} \leq 25.4$ Mpc, which is an extension of a complementary set of 140 more luminous ($\mathfrak{M}_{B}\leq-19.12$ mag) late-type galaxies. We find the PADFs of the two samples are, somewhat surprisingly, not strongly dissimilar; a result that may hold important implications for spiral formation theories. Our data show a distinct bimodal population manifest in the pitch angles of the Sa-Sc types and separately the Scd-Sm types, with Sa-Sc types having tighter spiral arms on average. Importantly, we uncover a distinct bifurcation of the BHMF, such that the Sa-Sc galaxies typically host so-called "supermassive" black holes ($M_{\bullet}\gtrsim10^6\,\mathrm{M_{\odot}}$), whereas Scd-Sm galaxies accordingly harbor black holes that are "less-than-supermassive" ($M_{\bullet}\lesssim10^6\,\mathrm{M_{\odot}}$). It is amongst this latter population of galaxies where we expect fruitful bounties of elusive intermediate-mass black holes (IMBHs), through which a better understanding will help form more precise benchmarks for future generations of gravitational wave detectors.
description: 39 pages, 17 figures, to be published in Universe
Theoretical analysis of anisotropic upper critical field of superconductivity in nodal-line semimetals
Creators: name: Endo, Junya
name: Matsuura, Hiroyasu
name: Ogata, Masao
Publisher: name: arXiv
Year: 2022
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We study the properties of the upper critical field of superconductivity in nodal-line semimetals in a continuous model, which has a nodal-line on the $k_{z} = 0$ plane. Using the semiclassical Green's function method, we calculate the upper critical field for the two limiting cases: the dirty limit with many impurities and the clean limit with few impurities. The results show the large anisotropy of the magnitude of the upper critical field and the unusual temperature dependence. The obtained results are compared with recent experimental data of PbTaSe$_{2}$.
description: 7 pages, 4 figures
ernesto De Carolis, Il Mobile a Pompei ed Ercolano. Letti, tavoli, sedie e armadi. Contributo alla tipologia dei mobili della prima età imperiale
Creators: name: Tronchin, Francesca
Publisher: name: Bonner Jahrbücher
Year: 2017

description: Rezension zu: Ernesto De Carolis, Il Mobile a Pompei ed Ercolano. Letti, tavoli, sedie e armadi. Contributo alla tipologia dei mobili della prima età imperiale. editor L’erma di Bretschneider, Rome 2007. 264 pages, 8 color plates, 107 black and white photographs, 30 digital reconstructions
description: Bonner Jahrbücher, Bd. 208.2008(2010): Bonner Jahrbücher
A convolution method for numerical solution of backward stochastic differential equations
Creators: name: Hyndman, Cody Blaine
name: Ngou, Polynice Oyono
Publisher: name: arXiv
Year: 2013
Subjects: subject: Probability (math.PR)
subject: Computational Finance (q-fin.CP)
subject: FOS: Mathematics
subject: FOS: Economics and business
subject: Primary 60H10, 65C30, Secondary 60H30

description: We propose a new method for the numerical solution of backward stochastic differential equations (BSDEs) which finds its roots in Fourier analysis. The method consists of an Euler time discretization of the BSDE with certain conditional expectations expressed in terms of Fourier transforms and computed using the fast Fourier transform (FFT). The problem of error control is addressed and a local error analysis is provided. We consider the extension of the method to forward-backward stochastic differential equations (FBSDEs) and reflected FBSDEs. Numerical examples are considered from finance demonstrating the performance of the method.
description: 29 pages, 4 figures; Revised (Version 3): Editorial changes; Additional references; Section 2: Removed derivation of implicit Euler scheme; Section 3: Further details on numerical implementation and algorithm; Section 4: Improved Error Analysis by adding new Theorem 4.2 on stability and convergence; Section 6: improved discussion of examples and numerical results
Computational and Experimental Study of the Mechanics of Embryonic Wound Healing
Creators: name: Wyczalkowski, Matthew A.
name: Varner, Victor D.
name: Taber, Larry A.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Tissues and Organs (q-bio.TO)
subject: FOS: Biological sciences

description: Wounds in the embryo show a remarkable ability to heal quickly without leaving a scar. Previous studies have found that an actomyosin ring ("purse string") forms around the wound perimeter and contracts to close the wound over the course of several dozens of minutes. Here, we report experiments that reveal an even faster mechanism which remarkably closes wounds by more than 50% within the first 30 seconds. Circular and elliptical wounds (~100 um in size) were made in the blastoderm of early chick embryos and allowed to heal, with wound area and shape characterized as functions of time. The closure rate displayed a biphasic behavior, with rapid constriction lasting about a minute, followed by a period of more gradual closure to complete healing. Fluorescent staining suggests that both healing phases are driven by actomyosin contraction, with relatively rapid contraction of fibers at cell borders within a relatively thick ring of tissue (several cells wide) around the wound followed by slower contraction of a thin supracellular actomyosin ring along the margin, consistent with a purse string mechanism. Finite-element modeling showed that this idea is biophysically plausible, with relatively isotropic contraction within the thick ring giving way to tangential contraction in the thin ring. In addition, consistent with experimental results, simulated elliptical wounds heal with little change in aspect ratio, and decreased membrane tension can cause these wounds to open briefly before going on to heal. These results provide new insight into the healing mechanism in embryonic epithelia.
description: 32 pages, 13 figures
Experimental generation of polarization entanglement from spontaneous parametric down-conversion pumped by spatiotemporally highly incoherent light
Creators: name: Li, Cheng
name: Braverman, Boris
name: Kulkarni, Girish
name: Boyd, Robert W.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: The influence of pump coherence on the entanglement produced in spontaneous parametric down-conversion (SPDC) is important to understand, both from a fundamental perspective, and from a practical standpoint for controlled generation of entangled states. In this context, it is known that in the absence of postselection, the pump coherence in a given degree of freedom (DOF) imposes an upper limit on the generated entanglement in the same DOF. However, the cross-influence of the pump coherence on the generated entanglement in a different DOF is not well-understood. Here, we experimentally investigate the effect of a spatiotemporally highly-incoherent (STHI) light-emitting diode (LED) pump on the polarization entanglement generated in SPDC. Our quantum state tomography measurements using multimode collection fibers to reduce the influence of postselection yield a two-qubit state with a concurrence of 0.531+/-0.006 and a purity of 0.647+/-0.005, in excellent agreement with our theoretically predicted concurrence of 0.552 and purity of 0.652. Therefore, while the use of an STHI pump causes reduction in the entanglement and purity of the output polarization two-qubit state, the viability of SPDC with STHI pumps is nevertheless important for two reasons: (i) STHI sources are ubiquitous and available at a wider range of wavelengths than lasers, and (ii) the generated STHI polarization-entangled two-photon states could potentially be useful in long-distance quantum communication schemes due to their robustness to scattering.
Oblique Quasi-Kink Modes in Solar Coronal Slabs Embedded in an Asymmetric Magnetic Environment: Resonant Damping, Phase and Group Diagrams
Creators: name: Chen, Shao-Xia
name: Li, Bo
name: Guo, Mingzhe
name: Shi, Mijie
name: Yu, Hui
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: There has been considerable interest in magnetoacoustic waves in static, straight, field-aligned, one-dimensional equilibria where the exteriors of a magnetic slab are different between the two sides. We focus on trapped, transverse fundamental, oblique quasi-kink modes in pressureless setups where the density varies continuously from a uniform interior (with density $ρ_{\rm i}$) to a uniform exterior on either side (with density $ρ_{\rm L}$ or $ρ_{\rm R}$), assuming $ρ_{\rm L}\leρ_{\rm R}\leρ_{\rm i}$. The continuous structuring and oblique propagation make our study new relative to pertinent studies, and lead to wave damping via the Alfv$\acute{\rm e}$n resonance. We compute resonantly damped quasi-kink modes as resistive eigenmodes, and isolate the effects of system asymmetry by varying $ρ_{\rm i}/ρ_{\rm R}$ from the ``Fully Symmetric'' ($ρ_{\rm i}/ρ_{\rm R}=ρ_{\rm i}/ρ_{\rm L}$) to the ``Fully Asymmetric'' limit ($ρ_{\rm i}/ρ_{\rm R}=1$). We find that the damping rates possess a nonmonotonic $ρ_{\rm i}/ρ_{\rm R}$-dependence as a result of the difference between the two Alfv$\acute{\rm e}$n continua, and resonant absorption occurs only in one continuum when $ρ_{\rm i}/ρ_{\rm R}$ is below some threshold. We also find that the system asymmetry results in two qualitatively different regimes for the phase and group diagrams. The phase and group trajectories lie essentially on the same side (different sides) relative to the equilibrium magnetic field when the configuration is not far from a ``Fully Asymmetric'' (``Fully Symmetric'') one. Our numerical results are understood by making analytical progress in the thin-boundary limit, and discussed for imaging observations of axial standing modes and impulsively excited wavetrains.
description: 31 pages (single column), 8 figures, accepted for publication in ApJ
Revisiting Open Source for Managers
Creators: name: Armintor, Benjamin J.
Publisher: name: Columbia University
Year: 2019
Subjects: Open source software
Computer software--Development
Management
Education, Higher--Technological innovations

description: The late-90's moment of open source software (OSS) presented itself as an anti-hierarchical mode of organization. By the mid-00's, however, OSS projects were articulated to corporate managerial strategies and a decade later 'Open' organizational strategies inform corporate models from RedHat to the US Armed Forces. In the mode of "questions and provocations," this presentation acknowledges that trajectory and echoes Sebastian Rahz's "Open Source for Managers" back 15 years later to ask how consortial OSS might, in the context of trends in tech workforce organization and higher-ed resourcing, be a professional development ground for developers moving into management. It will suggest that such development represents a concrete benefit for sponsoring organizations wary of "the Community" as an end unto itself, with examples drawn from my experience working in several OSS communities of interest and learning on-the-job to lead a team of developers.
Linear Response Properties of Solvated Systems: A Computational Study
Creators: name: Goletto, Linda
name: Gómez, Sara
name: Andersen, Josefine H.
name: Koch, Henrik
name: Giovannini, Tommaso
Publisher: name: arXiv
Year: 2022
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: We present a computational study of static and dynamic linear polarizabilities in solution. We use different theoretical approaches to describe solvent effects, ranging from quantum mechanics/molecular mechanics (QM/MM) to quantum embedding approaches. In particular, we consider non-polarizable and polarizable QM/MM methods, the latter based on the fluctuating charge (FQ) force field. In addition, we use a quantum embedding method defined in the context of multilevel Hartree-Fock (MLHF), where the system is divided into active and inactive regions, and combine it with a third layer described by means of the FQ model. The multiscale approaches are then used as reference wave functions for equation-of-motion coupled cluster (EOM-CC) response properties, allowing for the account of electron correlation. The developed models are applied to the calculation of linear response properties of two organic moieties -- namely, para-nitroaniline and benzonitrile -- in non-aqueous solvents -- 1,4-dioxane, acetonitrile, and tetrahydrofuran. The computed polarizabilities are then discussed in terms of the physico-chemical solute-solvent interactions described by each method (electrostatic, polarization and Pauli repulsion), and finally compared with the available experimental references.
description: 13 pages, 9 figures