cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Entanglement dynamics of electron-electron scattering in low-dimensional semiconductor systems
Creators: name: Buscemi, Fabrizio
name: Bordone, Paolo
name: Bertoni, Andrea
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We perform the quantitative evaluation of the entanglement dynamics in scattering events between two insistinguishable electrons interacting via Coulomb potential in 1D and 2D semiconductor nanostructures. We apply a criterion based on the von Neumann entropy and the Schmidt decomposition of the global state vector suitable for systems of identical particles. From the timedependent numerical solution of the two-particle wavefunction of the scattering carriers we compute their entanglement evolution for different spin configurations: two electrons with the same spin, with different spin, singlet, and triplet spin state. The procedure allows to evaluate the mechanisms that govern entanglement creation and their connection with the characteristic physical parameters and initial conditions of the system. The cases in which the evolution of entanglement is similar to the one obtained for distinguishable particles are discussed.
description: 22 pages, 7 figures, submitted to Physical Review A
Analysis of regularization methods for the solution of ill-posed problems involving discontinuous operators
Creators: name: Frühauf, F.
name: Scherzer, O.
name: Leitao, A.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics
subject: 65J20, 47A52

description: We consider a regularization concept for the solution of ill--posed operator equations, where the operator is composed of a continuous and a discontinuous operator. A particular application is level set regularization, where we develop a novel concept of minimizers. The proposed level set regularization is capable of handling changing topologies. A functional analytic framework explaining the splitting of topologies is given. The asymptotic limit of the level set regularization method is an evolution process, which is implemented numerically and the quality of the proposed algorithm is demonstrated by solving an inverse source problem.
description: 21 pages, 13 figures
Sunyer-i-Balaguer's Almost Elliptic Functions and Yosida's Normal Functions
Creators: name: Favorov, S. Ju.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Complex Variables (math.CV)
subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Mathematics
subject: 30D45 (Primary); 33E05, 43A60 (Secondary)

description: We study the properties of two classes of meromorphic functions in the complex plane. The first one is the class of almost elliptic functions in the sense of Sunyer-i-Balaguer. This is the class of meromorphic functions f such that the family of shifts f(z+h) (h are complex numbers) is normal with respect to the uniform convergence in the whole complex plane. Given two sequences of complex numbers, we provide sufficient conditions for them to be zeros and poles of some almost elliptic function. These conditions enable one to give (for the first time) explicit non-trivial examples of almost elliptic functions. The second class was introduced by K.Yosida, who called it a class of normal functions of the first category. This is the class of meromorphic functions f such that the family of shifts f(z+h)is normal with respect to the uniform convergence on compacta in the complex plane and no limit point of the family is a constant function. We give necessary and sufficient conditions for two sequences of complex numbers to be zeros and poles of some normal function of the first category and obtain a parametric representation for this class in terms of zeros and poles.
description: 26 pages, Bibliography 21 item
Bayesian Inference and the Shape of the Primordial Universe
Creators: name: Meldorf, Cole
Publisher: name: Zenodo
Year: 2024
Subjects: Cosmology
Inflation
Bayesian Statistics

description: Measurements of the curvature parameter ΩK using different cosmological data sets have been shown to give conflicting results to a significance of at least 2.5σ (Handley 2021b). This work seeks to determine how one’s choice of prior affects the calculation of ΩK , specifically the choice of a uniform curvature prior or a prior motivated by our understanding of inflation, resulting in a sharp peak at ΩK = 0. We compare the resulting Bayesian evidences for calculations using these two priors in an attempt to gauge the validity of our current inflationary models. We directly compare results that both do and do not include CMB lensing data, and results that use different sampling algorithms. We find that the choice of prior significantly affects the posterior distribution on ΩK , as well as the evidence recovered. However, while a sharply peaked prior improves the model fit when using the lensing data set, the opposite is true for the data set with no lensing. We also find that using a sharply peaked prior still results in tails to negative values in the ΩK posteriors. Finally, we show that widening and narrowing the peaked prior does not result in significant changes in the Bayesian evidence. The fact that the two data sets considered are optimally fit by two different models leads us to the conclusion that a curvature tension is present, and cannot be explained away by choice of prior.
Chemical evolution and origin of granites in the Lachlan Fold Belt
Creators: name: Chappell, B. W.
Publisher: name: Canberra, ACT : The Australian National University
Year: 2018
Subjects: subject: Granite Australia Lachlan Fold Belt
subject: Geochemistry Australia Lachlan Fold Belt
subject: Lachlan Fold Belt

description: The author has been involved in studying the granites of the Lachlan Fold Belt (LFB) since 1963 with this being the main focus of his scientific studies since 1973. This thesis brings together many of the publications that have arisen from that work and those 20 papers that are being submitted for examination are listed in Section 1 (pp. 2-3) and are bound together at the back of this volume. A complete list of the 114 publications for which this writer is an author is given in Section 10 (pp. 43-51). That list is comprehensive and again includes the 20 papers being examined. The remaining 94 papers are listed in support of the candidacy. Among those other papers, 37 deal with various aspects of granite studies, both in the LFB and elsewhere, and the remainder with a variety of geological and geochemical subjects.
Sexual abuse and depression and anxiety across 42 countries: An examination of moderating factors
Creators: name: Bőthe, Beáta
name: Anaïka François
name: Kraus, Shane W
name: Scoglio, Arielle
Publisher: name: OSF Registries
Year: 2024
Subjects: subject: Social and Behavioral Sciences
subject: Psychology
subject: FOS: Psychology

description: Sexual abuse and depression and anxiety across 42 countries: An examination of moderating factors
Edge singularities in high-energy spectra of gapped one-dimensional magnets in strong magnetic fields
Creators: name: Friedrich, A.
name: Kolezhuk, A. K.
name: McCulloch, I. P.
name: Schollwock, U.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We use the dynamical density matrix renormalization group technique to show that the high-energy part of the spectrum of a S=1 Haldane chain, placed in a strong external magnetic field $H$ exceeding the Haldane gap $Δ$, contains edge singularities, similar to those known to exist in the low-energy spectral response. It is demonstrated that in the frequency range $ω\gtrsim Δ$ the longitudinal (with respect to the applied field) dynamical structure factor is dominated by the power-law singularity $S^{\parallel}(q=π,ω)\propto(ω-ω_{0})^{-α'}$. We study the behavior of the high-energy edge exponent $α'$ and the edge $ω_{0}$ as functions of the magnetic field. The existence of edge singularities at high energies is directly related to the Tomonaga-Luttinger liquid character of the ground state at $H>Δ$ and is expected to be a general feature of one-dimensional gapped spin systems in high magnetic fields.
description: (v2) error in Eq.(11) corrected
Analytical parameter estimation of the SIR epidemic model. Applications to the COVID-19 pandemic
Creators: name: Prodanov, Dimiter
Publisher: name: arXiv
Year: 2020
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: Numerical Analysis (math.NA)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Biological sciences
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 92D30, 92C60, 26A36, 33F05, 65L09

description: The dramatic outbreak of the coronavirus disease 2019 (COVID-19) pandemics and its ongoing progression boosted the scientific community's interest in epidemic modeling and forecasting. The SIR (Susceptible-Infected-Removed) model is a simple mathematical model of epidemic outbreaks, yet for decades it evaded the efforts of the community to derive an explicit solution. The present work demonstrates that this is a non-trivial task. Notably, it is proven that the explicit solution of the model requires the introduction of a new transcendental special function, related to the Wright's Omega function. The present manuscript reports new analytical results and numerical routines suitable for parametric estimation of the SIR model. The manuscript introduces iterative algorithms approximating the incidence variable, which allows for estimation of the model parameters from the numbers of observed cases. The numerical approach is exemplified with data from the European Centre for Disease Prevention and Control (ECDC) for several European countries in the period Jan 2020 -- Jun 2020.
description: 17 pages; 5 figures
Resonant states in structured dielectric loss-free
media: study and characterization
Creators: name: Romano, Silvia
Publisher: name: Università degli Studi di Napoli Federico II
Year: 2015

description: The field enhancement in a structured dielectric sur-
face is a relatively unexplored area that has gained increasing attention in the last years.  Moreover, it would be of great interest the possibility of managing
surface electromagnetic states, mimicking surface plasmon resonances in terms of spatial localization, high field intensity and dispersion characteristics, while avoid-
ing heat dissipation due to metallic substrates.
In this thesis the possibility to excite high Q-factor resonances connected to high field enhancement factors in loss-free media, such as photonic crystal slabs, will
be reported.
The adipokine apelin-13 induces expression of prothrombotic tissue  factor
Creators: name: Pellegrino, Grazia
Publisher: name: Università degli Studi di Napoli Federico II
Year: 2015

description: Adipocytes are cells able to produce and secrete several active substances (adipokines) with direct effects on vascular cells. Apelin, one of the most recently identified adipokines has been studied in cardiovascular system physiology in regard to vessel vasodilation and myocardial contraction, but it has not yet completely characterised for its pathophysiological role in cardiovascular disease and especially in
acute coronary syndromes (ACS). Several studies have indicated that tissue factor (TF) plays a pivotal role in the pathophysiology of ACS by triggering the formation of intracoronary thrombi following endothelial injury. This study investigates the effects of apelin 12 and apelin 13
on TF in human umbilical endothelial cells (HUVECs) and monocytes.
Cells were stimulated with increasing concentrations of apelin 12 or apelin 13 and then processed to evaluate TF-mRNA levels by real-time PCR as well as TF expression/activity by FACS analysis and pro-coagulant activity. Finally, a potential molecular pathway involved in modulating this phenomenon was investigated. We demonstrate that apelin 13 but not apelin 12 induces transcription of mRNA for TF. In addition, we show that this adipokine promotes surface expression of TF that is functionally active. Apelin 13 effects on TF appear modulated by the activation of the G-protein-transcription factor nuclear factor (NF)k�B axis since G-protein inhibitors suppressed NF-kB mediated TF expression.
Data of the present study, although in vitro, indicate that apelin-13, induces a procoagulant phenotype in HUVECs and monocytes by promoting TF expression. These observations support the hypothesis that this adipokine might play a relevant role as an active partaker in athero-thrombotic disease.
Light speed variation from active galactic nuclei
Creators: name: Li, Hao
name: Ma, Bo-Qiang
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Recent studies on the high-energy photons from gamma-ray bursts~(GRBs) suggested a light speed variation $v(E)=c(1-E/E_{\mathrm{LV}})$ with $E_\mathrm{LV}=3.6\times 10^{17}$ GeV. We check this speed variation from previous observations on light curves of three active galactic nuclei (AGNs), namely Markarian 421 (Mrk 421), Markarian 501 (Mrk 501) and PKS 2155-304. We show that several phenomena related to the light curves of these AGNs can serve as the supports for the light speed variation determined from GRBs.
description: 10 latex pages, 3 figures
Terapia neoadiuvante nel cancro gastrico localmente avanzato: revisione della letteratura ed esperienza di un singolo centro.
Creators: name: Grassia, Sebastiano
Publisher: name: Università degli Studi di Napoli Federico II
Year: 2015

description: Il cancro gastrico (CG) rappresenta il quarto cancro per incidenza e la seconda causa di morte legata a neoplasia nel mondo, con oltre 930.000 nuovi casi e 700.000 morti all'anno. Nel mondo l'incidenza del CG varia considerevolmente con livelli massimi in Giappone, Cina e Russia, e minimi livelli in Australia e America del Nord. L'Italia si colloca in una zona intermedia con un'incidenza più elevata nelle regioni centro-settentrionali. La chirurgia è ancora l'unica terapia curativa per il cancro gastrico ad estensione loco regionale. A tal proposito è importante ottenere margini liberi da infiltrazione neoplastica anche microscopica (R0) ed effettuare un'adeguata dissezione linfonodale. Purtroppo nella maggior parte dei casi si giunge alla diagnosi di cancro gastrico quando la malattia neoplastica è ad uno stadio localmente o diffusamente avanzato. Inoltre, anche quando è possibile realizzare una resezione con intento curativo è frequente osservare recidive nei pazienti affetti da CG. Tali considerazioni hanno portato allo sviluppo di differenti schemi terapeutici al fine di ottenere un miglioramento prognostico di questi pazienti. In aggiunta agli schemi di chemioterapia adiuvante, ampiamente studiati, molti autori hanno riportato risultati incoraggianti con l'impiego della chemioterapia neoadiuvante nel cancro gastrico localmente avanzato descrivendo in diversi articoli un miglioramento in termini di sopravvivenza globale (OS) e sopravvivenza libera da malattia (DFS). Scopo di questa tesi è fornire una panoramica quanto più completa possibile sui più recenti sviluppi in questo campo, focalizzando l'attenzione sugli effetti del trattamento neo-adiuvante nel cancro gastrico localmente avanzato. I dati presenti in letteratura suggeriscono un effetto benefico della CT neoadiuvante sulla sopravvivenza. Dal 01/2010 al 06/2014,  presso l'area funzionale di Chirurgia Generale ad indirizzo addominale (direttore Prof. Andrea Renda), sono stati reclutati 24 pz affetti da adenocarcinoma gastrico localmente avanzato. Tutti i pz sono stati sottoposti a trattamento chirurgico ed in 2 casi si è fatto ricorso anche alla terapia neoadiuvante, osservando in un caso progressione di malattia ed in un altro mancato downstaging, con ripresa di malattia entro un anno. A causa del ristretto campione la nostra esperienza non ha raggiunto livelli di significatività. Tale esperienza preliminare rappresenta un punto di inizio da cui partire con l'obiettivo di aumentare il campione in esame. Sono necessari ulteriori studi con popolazioni più ampie per chiarire i diversi punti ancora controversi, quali il reale effetto sulla sopravvivenza, il rischio di ritardo nel trattamento chirurgico, la tossicità degli schemi adottati, il migliore schema terapeutico da adottare.
SOLEIL: Streaming Of Large scale Events over Internet cLouds
Creators: name: Miniero, Lorenzo
Publisher: name: Università degli Studi di Napoli Federico II
Year: 2015

description: This Ph.D. Thesis deals with the design and realization of a streaming platform specifically targeted at large-scale and live, low delay, events. The streaming platform, called SOLEIL (Streaming Of Large scale Events over Internet cLouds), is conceived to be compliant, at its edge nodes, with the WebRTC specification, meaning users can take advantage of its capabilities using a simple browser. Details on both the design and realization processes are provided, and a thorough experimental campaign will prove the validity of the achieved results.
Stimulation of Formation of Pre-stomach Type of Digestion in Young Ruminants
Creators: name: Nikolay Zuev, Vitaly Shumsky
Publisher: name: TuEngr Group
Year: 2021
Subjects: Pre-ventricle
Calves digestion structure
Ruminant mammal
Symbiont microorganism
Lactobacillus
Calves feed
Montmorelenite
Rennet
Casein
Rumen fermentation indices.

description: International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies, 12, 12, 12A12A: 1-7
Supersymmetric AdS_3 solutions of type IIB supergravity
Creators: name: Gauntlett, Jerome P.
name: Mac Conamhna, Oisin A. P.
name: Mateos, Toni
name: Waldram, Daniel
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: For every positively curved Kahler-Einstein manifold in four dimensions we construct an infinite family of supersymmetric solutions of type IIB supergravity. The solutions are warped products of AdS_3 with a compact seven-dimensional manifold and have non-vanishing five-form flux. Via the AdS/CFT correspondence, the solutions are dual to two-dimensional conformal field theories with (2,0) supersymmetry. The corresponding central charges are rational numbers.
description: Dedicated to Rafael Sorkin in celebration of his 60th birthday; 5 pages, latex. v2, typos corrected, to appear in PRL
Consistency of the jackknife-after-bootstrap variance estimator for the bootstrap quantiles of a studentized statistic
Creators: name: Lahiri, S. N.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Statistics Theory (math.ST)
subject: FOS: Mathematics
subject: 62G05 (Primary) 62G25 (Secondary)

description: Efron [J. Roy. Statist. Soc. Ser. B 54 (1992) 83--111] proposed a computationally efficient method, called the jackknife-after-bootstrap, for estimating the variance of a bootstrap estimator for independent data. For dependent data, a version of the jackknife-after-bootstrap method has been recently proposed by Lahiri [Econometric Theory 18 (2002) 79--98]. In this paper it is shown that the jackknife-after-bootstrap estimators of the variance of a bootstrap quantile are consistent for both dependent and independent data. Results from a simulation study are also presented.
description: Published at http://dx.doi.org/10.1214/009053605000000507 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Learning to Denoise Astronomical Images with U-nets
Creators: name: Vojtekova, Antonia
name: Lieu, Maggie
name: Valtchanov, Ivan
name: Altieri, Bruno
name: Old, Lyndsay
name: Chen, Qifeng
name: Hroch, Filip
Publisher: name: arXiv
Year: 2020
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Astronomical images are essential for exploring and understanding the universe. Optical telescopes capable of deep observations, such as the Hubble Space Telescope, are heavily oversubscribed in the Astronomical Community. Images also often contain additive noise, which makes de-noising a mandatory step in post-processing the data before further data analysis. In order to maximise the efficiency and information gain in the post-processing of astronomical imaging, we turn to machine learning. We propose Astro U-net, a convolutional neural network for image de-noising and enhancement. For a proof-of-concept, we use Hubble space telescope images from WFC3 instrument UVIS with F555W and F606W filters. Our network is able to produce images with noise characteristics as if they are obtained with twice the exposure time, and with minimum bias or information loss. From these images, we are able to recover 95.9% of stars with an average flux error of 2.26%. Furthermore the images have, on average, 1.63 times higher signal-to-noise ratio than the input noisy images, equivalent to the stacking of at least 3 input images, which means a significant reduction in the telescope time needed for future astronomical imaging campaigns.
Cops or robbers - a bistable society
Creators: name: Kulakowski, Krzysztof
Publisher: name: arXiv
Year: 2008
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: The norm game described by Axelrod in 1985 was recently treated with the master equation formalism. Here we discuss the equations, where {\it i)} those who break the norm cannot punish and those who punish cannot break the norm, {\it ii)} the tendency to punish is suppressed if the majority breaks the norm. The second mechanism is new. For some values of the parameters the solution shows the saddle-point bifurcation. Then, two stable solutions are possible, where the majority breaks the norm or the majority punishes. This means, that the norm breaking can be discontinuous, when measured in the social scale. The bistable character is reproduced also with new computer simulations on the Erd{\H o}s--Rényi directed network.
description: 8 pages, 2 figures. Some misleading sentences are removed from section 3
Soliton solutions of the improved quark mass density-dependent model at finite temperature
Creators: name: Mao, Hong
name: Su, Ru-Keng
name: Zhao, Wei-Qin
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The improved quark mass density-dependent model (IQMDD) based on soliton bag model is studied at finite temperature. Appling the finite temperature field theory, the effective potential of the IQMDD model and the bag constant $B(T)$ have been calculated at different temperatures. It is shown that there is a critical temperature $T_{C}\simeq 110 \mathrm{MeV}$. We also calculate the soliton solutions of the IQMDD model at finite tmperature. It turns out that when $TT_{C}$ the bag constant $B(T)=0$ and there is no soliton solution, therefore, the confinement of quarks are removed quickly.
description: 10 pages, 9 figures; Version to appear in Physical Review C
Materiali leggeri magneto-sensibili basati su strutture polimeriche espanse e particelle con distribuzione spaziale controllata mediante campo magnetico
Creators: name: D'Auria, Marco
Publisher: name: Università degli Studi di Napoli Federico II
Year: 2015

description: I materiali magneto-reologici e magneto-elastici rappresentano una specifica classe di materiali intelligenti che rispondono ad un campo magnetico esterno manifestando un rapido e reversibile cambiamento delle loro proprietà visco-elastiche. Le proprietà più significative di questi materiali sono l'effetto magnetostrittivo e la variazione della rigidezza in seguito all'applicazione di un campo magnetico.
In passato sono stati proposti diversi materiali magneto-reologici solidi, ma la loro elevata densità richiedeva magnetici molto alti per distribuire le particelle in maniera ottimale e sfruttare la loro risposta magneto-elastica, riducendo in questo modo i loro potenziali campi di applicazione. La necessità di ridurre sia il peso delle strutture sia l'intensità dei campi utilizzati hanno creato una spinta verso lo sviluppo di materiali a bassa densità: i materiali porosi rappresentano una possibile soluzione a tali esigenze. I materiali espansi sono caratterizzati da una riduzione delle prestazioni meccaniche rispetto ai corrispettivi materiali compatti in proporzione all'aumento della porosità. Un modo per migliorarne le proprietà meccaniche è di rinforzali con fibre corte o additivi particellari. Inoltre, a differenza dei fluidi magneto-reologici, i solidi magneto-elastici possono essere facilmente modellati e caratterizzati da una fissata distribuzione spaziale delle particelle definita durante la formatura, ottimizzando la risposta in una direzione preferenziale.
Partendo da queste considerazioni, sono stati sviluppati materiali magneto-elastici a bassa densità, costituiti da una matrice polimerica espansa al cui interno sono state disperse particelle magnetiche. Al fine di conferire e gestire le proprietà meccaniche e magneto-elastiche dei materiali, è stato applicato un campo magnetico durante il processo di espansione in modo da controllare la distribuzione delle particelle in strutture a catena, allineate lungo le linee del campo magnetico. Tale configurazione è stata consolidata dopo la reticolazione del polimero. I campioni con particelle in strutture a catena hanno mostrato migliorate prestazioni meccaniche  in termini sia di modulo di Young a compressione (lungo la direzione di allineamento) sia di modulo di taglio (nella direzione ortogonale a quella di allineamento) rispetto agli espansi puri e agli espansi con una distribuzione casuale delle particelle. Per tutti i sistemi è stato studiato il comportamento magneto-meccanico, manifestando una risposta magneto-elastica in termini di variazioni di forza anche utilizzando campi magnetici di intensità moderata.
Parameter Degeneracy in Flavor-Dependent Reconstruction of Supernova Neutrino Fluxes
Creators: name: Minakata, H.
name: Nunokawa, H.
name: Tomas, R.
name: Valle, J. W. F.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We reexamine the possibility of reconstructing the initial fluxes of supernova neutrinos emitted in a future core-collapse galactic supernova explosion and detected in a Megaton-sized water Cherenkov detector. A novel key element in our method is the inclusion, in addition to the total and the average energies of each neutrino species, of a "pinching" parameter characterizing the width of the distribution as a fit parameter. We uncover in this case a continuous degeneracy in the reconstructed parameters of supernova neutrino fluxes at the neutrinosphere. We analyze in detail the features of this degeneracy and show how it occurs irrespective of the parametrization used for the distribution function. Given that this degeneracy is real we briefly comment on possible steps towards resolving it, which necessarily requires going beyond the setting presented here.
description: 28 pages, 37 figures, version with some improvements in the text and some new references, conclusions unchanged, to appear in JCAP
A Mathematical Comparison of the Schwarzschild and Kerr Metrics
Creators: name: Pommaret, J. -F.
Publisher: name: arXiv
Year: 2020
Subjects: subject: General Physics (physics.gen-ph)
subject: FOS: Physical sciences
subject: 18G15, 35Q75, 53B20, 83C15, 83C20

description: A few physicists have recently constructed the generating compatibility conditions (CC) of the Killing operator for the Minkowski (M) , Schwarzschild (S) and Kerr (K) metrics. They discovered second order CC, well known for M, but also third order CC for S and K. In a recent paper, we have studied the cases of M and S, without using specific technical tools such as Teukolski scalars or Killing-Yano tensors. However, even if S($m$) and K($m,a$) are depending on constant parameters in such a way that S $\rightarrow $ M when $m \rightarrow 0$ and K $\rightarrow$ S when $ a \rightarrow 0$, the CC of S do not provide the CC of M when $m \rightarrow 0$ while the CC of K do not provide the CC of S when $a\rightarrow 0$. In this paper, using tricky motivating examples of operators with constant or variable parameters, we explain why the CC are depending on the choice of the parameters. In particular, the only purely intrinsic objects that can be defined, namely the extension modules, may change drastically. As the algebroid bracket is compatible with the {\it prolongation/projection} (PP) procedure, we provide for the first time all the CC for K in an intrinsic way, showing that they only depend on the underlying Killing algebras and that the role played by the Spencer operator is crucial. We get K$
description: This paper achieves the formal study of the Kerr metric that we had only sketched in J. of Modern Physics, 9 (2018) 1970-2007 (arXiv:1805.11958v2)
Design and characterization of a low-vibration laboratory with cylindrical inertia block geometry
Creators: name: Gong, Wenjie
name: Liu, Yu
name: Liao, Wan-Ting
name: Gibbons, Joseph
name: Hoffman, Jennifer E.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: Many modern nanofabrication and imaging techniques require an ultra-quiet environment to reach optimal resolution. Isolation from ambient vibrations is often achieved by placing the sensitive instrument atop a massive block that floats on air springs and is surrounded by acoustic barriers. Because typical building noise drops off above 120 Hz, it is advantageous to raise the flexural resonance frequencies of the inertia block and instrument far above 120 Hz. However, it can be challenging to obtain a high fundamental frequency of the floating block using a simple rectangular design. Here we design, construct, and characterize a vibration isolation system with a cylindrical inertia block, whose lowest resonance frequency of 249 Hz shows good agreement between finite element analysis simulation and directly measured modes. Our simulations show that a cylindrical design can achieve higher fundamental resonance frequency than a rectangular design of the same mass.
description: accepted to Review of Scientific Instruments
The 4-Coumarate:coenzyme A ligases from Nicotiana tabacum and Arabidopsis thaliana : characterization of cDNA clones, gene families, recombinant proteins, and antisense transgenic-plants
Creators: name: Lee, Diana
Publisher: name: University of British Columbia
Year: 2009

description: The cDNAs encoding 4-coumarate:coenzyme A ligase (4CL), an enzyme in the general phenylpropanoid pathway, were cloned from Nicotiana tabacum and Arabidopsis thaliana. In tobacco, 4CL was encoded by a gene family and northern blot analysis demonstrated that the steady-state RNA levels were highest in stems, ovaries, and non-pigmented portions of the corolla. Two 4CL cDNAs, which were 80% identical to each other at the nucleotide level, were expressed in E. coli. The relative abilities of the recombinant-4CL proteins to utilize 4-coumarate, ferulate, and caffeate as substrates were comparable to that of the 4CL activity found in tobacco-stem extracts. Both recombinant-4CL proteins utilized cinnamate as a substrate, an activity not observed in tobacco extracts. This activity towards cinnamate was inhibited by a modifying-component found in tobacco extracts and the evidence suggests that the substrate specificity of 4CL is, in part, determined by post-translational modification such as phosphorylation. In Arabidopsis, 4CL was shown to be encoded by a single gene. Northern blot analysis indicated that, like tobacco, 4CL steady-state RNA levels were highest in the bolting stem. The Arabidopsis-4CL cDNA was inserted in antisense orientation behind the CaMV 35S or parsley 4CL1 promoters and introduced into Arabidopsis. Transgenic plants were analyzed by western blot analysis and plants with severely suppressed-4CL protein levels were further analyzed. One transgenic-Arabidopsis line had greater than 90% decrease in 4CL enzyme activity and accumulated significantly less (50%) lignin in the bolting stem as compared to wild-type untransformed plants. Despite the decrease in 4CL mRNA, 4CL protein, and 4CL enzyme activity, anthocyanin accumulation was unaffected in the antisense-4CL Arabidopsis-lines. Mature, fully-expanded Arabidopsis-leaves were wounded and this resulted in a coordinated increase in RNA transcripts from genes encoding enzymes in the oxidative pentose phosphate pathway, the shikimic acid pathway, and the general phenylpropanoid pathway. The coordinated activation of gene expression was observed in the wild-type and antisense-4CL transgenic lines suggesting that wound-induced gene expression is not dependent on the carbon flow through the 4CLcatalyzed step.
Zero-field magnetic ground state of EuMg$_2$Bi$_2$
Creators: name: Pakhira, Santanu
name: Heitmann, Thomas
name: Riberolles, S. X. M.
name: Ueland, B. G.
name: McQueeney, R. J.
name: Johnston, D. C.
name: Vaknin, David
Publisher: name: arXiv
Year: 2020
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Layered trigonal EuMg$_2$Bi$_2$ is reported to be a topological semimetal that hosts multiple Dirac points that may be gapped or split by the onset of magnetic order. Here, we report zero-field single-crystal neutron-diffraction and bulk magnetic susceptibility measurements versus temperature $χ(T)$ of EuMg$_2$Bi$_2$ that show the intraplane ordering is ferromagnetic (Eu$^{2+},\, S= 7/2$) with the moments aligned in the $ab$-plane while adjacent layers are aligned antiferromagnetically (i.e., A-type antiferromagnetism) below the Néel temperature.
Closed k-strings in SU(N) gauge theories : 2+1 dimensions
Creators: name: Bringoltz, Barak
name: Teper, Michael
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We calculate the ground state energies of closed k-strings in (2+1)-dimensional SU(N) gauge theories, for N=4,5,6,8 and k=2,3,4. From the dependence of the ground state energy on the string length, we infer that such k-strings are described by an effective string theory that is in the same bosonic universality class (Nambu-Goto) as the fundamental string. When we compare the continuum k-string tensions to the corresponding fundamental string tensions, we find that the ratios are close to, but typically 1-2 percent above, the Casimir scaling values favoured by some theoretical approaches. Fitting the N-dependence in a model-independent way favours an expansion in 1/N (as in Casimir scaling) rather than the 1/N^2 that is suggested by naive colour counting. We also observe that the low-lying spectrum of k-string states falls into sectors that belong to particular irreducible representations of SU(N), demonstrating that the dynamics of string binding knows about the full gauge group and not just about its centre.
description: 22 pages, 8 figures
On the quantum analogue of Galileo's leaning tower experiment
Creators: name: Ali, Md. Manirul
name: Majumdar, A. S.
name: Home, Dipankar
name: Pan, Alok Kumar
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: The quantum analogue of Galileo's leaning tower experiment is revisited using wave packets evolving under the gravitational potential. We first calculate the position detection probabilities for particles projected upwards against gravity around the classical turning point and also around the point of initial projection, which exhibit mass dependence at both these points. We then compute the mean arrival time of freely falling particles using the quantum probability current, which also turns out to be mass dependent. The mass dependence of both the position detection probabilities and the mean arrival time vanish in the limit of large mass. Thus, compatibility between the weak equivalence principle and quantum mechanics is recovered in the macroscopic limit of the latter.
description: Latex, 12 pages, 1 figure, uses IOP style, clarifications and references added
The field nature of spin for electromagnetic particle
Creators: name: Chernitskii, Alexander A.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The field nature of spin in the framework of the field electromagnetic particle concept is considered. A mathematical character of the fine structure constant is discussed. Three topologically different field models for charged particle with spin are investigated in the scope of the linear electrodynamics. A using of these field configurations as an initial approximation for an appropriate particle solution of nonlinear electrodynamics is discussed.
description: 4 pages, talk given at The 17th International Spin Physics Symposium, SPIN2006, October 2-7, 2006, Kyoto, Japan
Fast meningioma segmentation in T1-weighted MRI volumes using a lightweight 3D deep learning architecture
Creators: name: Bouget, David
name: Pedersen, André
name: Hosainey, Sayied Abdol Mohieb
name: Vanel, Johanna
name: Solheim, Ole
name: Reinertsen, Ingerid
Publisher: name: arXiv
Year: 2020
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
subject: I.4.6; J.3

description: Automatic and consistent meningioma segmentation in T1-weighted MRI volumes and corresponding volumetric assessment is of use for diagnosis, treatment planning, and tumor growth evaluation. In this paper, we optimized the segmentation and processing speed performances using a large number of both surgically treated meningiomas and untreated meningiomas followed at the outpatient clinic. We studied two different 3D neural network architectures: (i) a simple encoder-decoder similar to a 3D U-Net, and (ii) a lightweight multi-scale architecture (PLS-Net). In addition, we studied the impact of different training schemes. For the validation studies, we used 698 T1-weighted MR volumes from St. Olav University Hospital, Trondheim, Norway. The models were evaluated in terms of detection accuracy, segmentation accuracy and training/inference speed. While both architectures reached a similar Dice score of 70% on average, the PLS-Net was more accurate with an F1-score of up to 88%. The highest accuracy was achieved for the largest meningiomas. Speed-wise, the PLS-Net architecture tended to converge in about 50 hours while 130 hours were necessary for U-Net. Inference with PLS-Net takes less than a second on GPU and about 15 seconds on CPU. Overall, with the use of mixed precision training, it was possible to train competitive segmentation models in a relatively short amount of time using the lightweight PLS-Net architecture. In the future, the focus should be brought toward the segmentation of small meningiomas (less than 2ml) to improve clinical relevance for automatic and early diagnosis as well as speed of growth estimates.
description: 15 pages, 7 figures, submitted to SPIE journal of Medical Imaging
Effect of structural disorder on the Kitaev magnet Ag$_{3}$LiIr$_{2}$O$_{6}$
Creators: name: Bahrami, Faranak
name: Kenney, Eric M.
name: Wang, Chennan
name: Berlie, Adam
name: Lebedev, Oleg I.
name: Graf, Michael J.
name: Tafti, Fazel
Publisher: name: arXiv
Year: 2020
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Searching for an ideal Kitaev spin liquid candidate with anyonic excitations and long-range entanglement has motivated the synthesis of a new family of intercalated Kitaev magnets such as H$_{3}$LiIr$_{2}$O$_{6}$, Cu$_{2}$IrO$_{3}$, and Ag$_{3}$LiIr$_{2}$O$_{6}$. The absence of a susceptibility peak and a two-step release of the magnetic entropy in these materials has been proposed as evidence of proximity to the Kitaev spin liquid. Here we present a comparative study of the magnetic susceptibility, heat capacity, and muon spin relaxation ($μ$SR) between two samples of Ag$_{3}$LiIr$_{2}$O$_{6}$ in the clean and disordered limits. In the disordered limit, the absence of a peak in either susceptibility or heat capacity and a weakly depolarizing $μ$SR signal may suggest a proximate spin liquid ground state. In the clean limit, however, we resolve a peak in both susceptibility and heat capacity data, and observe clear oscillations in $μ$SR that confirm long-range antiferromagnetic ordering. The $μ$SR oscillations fit to a Bessel function, characteristic of an incommensurate order, as reported in the parent compound $α$-Li$_{2}$IrO$_{3}$. Our results clarify the role of structural disorder in the intercalated Kitaev magnets.
description: 8 pages, 9 figures
Timing of the Accreting Millisecond Pulsar XTE J1814-338
Creators: name: Papitto, A.
name: Di Salvo, T.
name: Burderi, L.
name: Menna, M. T.
name: Lavagetto, G.
name: Riggio, A.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present a precise timing analysis of the accreting millisecond pulsar XTE J1814-338 during its 2003 outburst, observed by RXTE. A full orbital solution is given for the first time; Doppler effects induced by the motion of the source in the binary system were corrected, leading to a refined estimate of the orbital period, P_orb=15388.7229(2)s, and of the projected semimajor axis, a sini/c= 390.633(9) lt-ms. We could then investigate the spin behaviour of the accreting compact object during the outburst. We report here a refined value of the spin frequency (nu=314.35610879(1) Hz) and the first estimate of the spin frequency derivative of this source while accreting (nu^dot=(-6.7 +/- 0.7) 10^(-14) Hz/s). This spin down behaviour arises when both the fundamental frequency and the second harmonic are taken into consideration. We discuss this in the context of the interaction between the disc and the quickly rotating magnetosphere, at accretion rates sufficiently low to allow a threading of the accretion disc in regions where the Keplerian velocity is slower than the magnetosphere velocity. We also present indications of a jitter of the pulse phases around the mean trend, which we argue results from movements of the accreting hotspots in response to variations of the accretion rate.
description: 7 pages, 4 figures, Accepted for publication by MNRAS
Entanglement and Quantum Groups
Creators: name: Korbicz, J. K.
name: Wehr, J.
name: Lewenstein, M.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: Operator Algebras (math.OA)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We describe quantum mechanical entanglement in terms of compact quantum groups. We prove an analog of positivity of partial transpose (PPT) criterion and formulate a Horodecki-type Theorem.
description: final version
Adaptive tip-enhanced nano-spectroscopy
Creators: name: Lee, Dong Yun
name: Park, Chulho
name: Choi, Jinseong
name: Jeong, Mun Seok
name: Raschke, Markus B.
name: Park, Kyoung-Duck
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optics (physics.optics)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Tip-enhanced nano-spectroscopy and -imaging, such as tip-enhanced photoluminescence (TEPL), tip-enhanced Raman spectroscopy (TERS), and others, have become indispensable from materials science to single molecule studies. However, the techniques suffer from inconsistent performance due to lack of nanoscale control of tip apex structure, which often leads to irreproducible spectral, spatial, and polarization resolved imaging. Instead of refining tip-fabrication to resolve this problem, we pursue the inverse approach of optimizing the nano-optical vector-field at the tip apex via adaptive optics. Specifically, we demonstrate dynamic wavefront shaping of the excitation field to effectively couple light to the tip and adaptively control for enhanced sensitivity and polarization-controlled TEPL and TERS, with performance exceeding what can be achieved by conventional tip-fabrication and optimal excitation polarization. Employing a sequence feedback algorithm, we achieve 4.4$\times$10$^4$-fold TEPL enhancement of a WSe$_2$ monolayer which is >2$\times$ larger than the normal TEPL intensity without wavefront shaping, as well as the largest plasmon-enhanced PL intensity of a transition metal dichalcogenide (TMD) monolayer reported to date. In addition, with dynamical near-field polarization control in TERS, we demonstrate the investigation of conformational heterogeneity of brilliant cresyl blue (BCB) molecules as well as the controllable observation of IR-active modes due to a large gradient field effect. Adaptive tip-enhanced spectroscopy and imaging thus provides for a new systematic approach towards computational nanoscopy making optical nano-imaging more robust, versatile, and widely deployable.
description: 21 pages, 4 figures
Hansenocaris undetermined
Creators: name: Olesen, Jørgen
name: Grygier, Mark J.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Maxillopoda
Hansenocarididae
Hansenocaris
Hansenocaris undetermined

description: Y-nauplius Type M
Figs 2, 14A–F
Type M – Dreyer et al. 2023a: figs 3, 5a, c, tables s1–s2.
Material examined
JAPAN – Okinawa, Sesoko I., laboratory pier, 26°38ʹ09.4ʺ N, 127°51ʹ55.2ʺ E • 3 LSN; 1991–2005 • 6 LSN, 3 of which molted to cyprids; 2018–2019 (Tables 1 and S1).
Description
LAST-STAGE NAUPLIUS (LSN). Lecithotrophic. Body narrowly ovate, almost lanceolate, in dorso-ventral view; about 2.0 times as long as wide; lateral margins without marked discontinuity between cephalic shield and trunk. In lateral view, trunk axis bent ca 30° downwards with respect to cephalic axis. Length 290–310 µm (without dorso-caudal spine), greatest width ca 150 µm, greatest dorso-ventral thickness ca 90 µm. Labrum produced as sub-triangular, nearly semi-circular elevation divided into facets by cuticular ridges; pore pattern not examined in detail but at least 2–3 pores present along posterior half of midline. Caudal end attenuate, terminating in ca 60 µm long, annulate but not obviously spiny dorso-caudal spine, this being turned upwards 30° with respect to trunk axis and accompanied ventrally by pair of triangular furcal spines ca 7–10 µm long.
CYPRID VIEWED THROUGH CUTICLE OF LSN. Body overall weakly brownish with distinctly darker-brown telson. Telson portion of gut-like tube containing orange yolk granules. Telson longer than wide and about half as long as thorax.
Identification and variation
Easy recognizable by its general body form, labral outline, long and annulate but not obviously spinose dorso-caudal spine and the distinct brown pigmentation of the cyprid’s telson. Little variation is evident among LSN specimens.
Distribution
Japan (Sesoko Island, Okinawa).
description: Published as part of Olesen, Jørgen & Grygier, Mark J., 2024, Taxonomic diversity of marine planktonic ' y-larvae' (Crustacea: Facetotecta) from a coral reef hotspot locality (Japan, Okinawa), with a key to y-nauplii, pp. 1-90 in European Journal of Taxonomy 929 (1) on page 37, DOI: 10.5852/ejt.2024.929.2479, http://zenodo.org/record/10876286