cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
$β$-Carotene bioavailability and conversion efficiency are significantly affected by sex in rats. First observation suggesting a possible hormetic regulation of vitamin A metabolism in female rats
Creators: name: Borel, Patrick
name: Troadec, Romane
name: Damiani, Morgane
name: Halimi, Charlotte
name: Nowicki, Marion
name: Guichard, Philippe
name: Margier, Marielle
name: Astier, Julien
name: Grino, Michel
name: Reboul, Emmanuelle
name: Landrier, Jean-françois
name: Landrier, Jean-François
Publisher: name: arXiv
Year: 2021
Subjects: subject: Tissues and Organs (q-bio.TO)
subject: FOS: Biological sciences

description: Scope: To study the effect of variation in dietary vitamin A (VA) content on its hepatic and intestinal metabolism. Methods and results: Adult female and male rats were fed with diets containing 400, 2300, or 9858 IU/kg VA for 31-33 weeks. VA concentrations were measured in plasma and liver. Bioavailability and intestinal conversion efficiency of $β$-carotene to VA were assessed by measuring postprandial plasma $β$-carotene and retinyl palmitate concentrations after force-feeding rats with $β$-carotene. Expression of genes involved in VA metabolism, together with concentrations of RBP4, BCO1 and SR-BI proteins, were measured in the intestine and liver of female rats. Plasma retinol concentrations were lower and hepatic free retinol concentrations were higher in females than in males. There was no effect of dietary VA content on $β$-carotene bioavailability and its conversion efficiency, but bioavailability was higher and conversion efficiency was lower in females than in males. The expression of most genes exhibited a U-shaped dose response curve depending on VA intake. Main conclusions: $β$-Carotene bioavailability and conversion efficiency to VA are affected by the sex of rats. Results of gene expression suggest a hormetic regulation of VA metabolism in female rats.
SWIFT J1753.5-0127: a surprising optical/X-ray cross-correlation function
Creators: name: Durant, Martin
name: Gandhi, Poshak
name: Shahbaz, Tariq
name: Fabian, Andy
name: Miller, Jon
name: Dhillon, V. S.
name: Marsh, Tom R.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We have conducted optical and X-ray simultaneous observations of SWIFT J1753.5-0127 with RXTE and ULTRACAM, while the system persisted in its relatively bright low/hard state. In the cross-correlation function (CCF), we find that the optical leads the X-rays by a few seconds with a broad negative peak, and has a smaller positive peak at positive lags. This is markedly different from what was seen for the similarly interesting system XTE J1118+480, and the first time such a correlation function has been so clearly measured. Furthermore, there appears to be a significant variation of the correlation with X-ray energy. We suggest a physical scenario for its origin.
description: 10 page manuscript. Accepted for publication in ApJL
Baryon Operators of Higher Twist in QCD and Nucleon Distribution Amplitudes
Creators: name: Braun, V. M.
name: Manashov, A. N.
name: Rohrwild, J.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We develop a general theoretical framework for the description of higher-twist baryon operators which makes maximal use of the conformal symmetry of the QCD Lagrangian. The conformal operator basis is constructed for all twists. The complete analysis of the one-loop renormalization of twist-4 operators is given. The evolution equation for three-quark operators of the same chirality turns out to be completely integrable. The spectrum of anomalous dimensions coincides in this case with the energy spectrum of the twist-4 subsector of the SU(2,2) Heisenberg spin chain. The results are applied to give a general classification and calculate the scale dependence of subleading twist-4 nucleon distribution amplitudes that are relevant for hard exclusive reactions involving a helicity flip. In particular we find an all-order expression (in conformal spin) for the contributions of geometric twist-3 operators to the (light-cone) twist-4 nucleon distribution amplitudes, which are usually referred to as Wandzura-Wilczek terms.
description: 60 pages, 6 figures, pdflatex, typos corrected
Role of covalent Fe-As bonding in the magnetic moment formation and exchange mechanisms in iron-pnictide superconductors
Creators: name: Belashchenko, K. D.
name: Antropov, V. P.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The electronic origin of the huge magnetostructural effect in layered Fe-As compounds is elucidated using LiFeAs as a prototype. The crucial feature of these materials is the strong covalent bonding between Fe and As, which tends to suppress the exchange splitting. The bonding-antibonding splitting is very sensitive to the distance between Fe and As nuclei. We argue that the fragile interplay between bonding and magnetism is universal for this family of compounds. The exchange interaction is analyzed in real space, along with its correlation with covalency and doping. The range of interaction and itinerancy increase as the Fe-As distance is decreased. Superexchange makes a large antiferromagnetic contribution to the nearest-neighbor coupling, which develops large anisotropy when the local moment is not too small. This anisotropy is very sensitive to doping.
description: 4+ pages, 4 color eps files; revised version accepted in Phys. Rev. B
Observation of $η'$ decays to $π^+π^-π^0$ and $π^+π^-\e^+e^-$
Creators: name: CLEO Collaboration
name: Naik, P.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Using psi(2S) --> pi+ pi- J/psi, J/psi --> gamma eta' events acquired with the CLEO-c detector at the CESR e+e- collider, we make the first observations of the decays eta' --> pi+ pi- pi0 and eta' --> pi+ pi- e+ e-, measuring absolute branching fractions (37 +11 -9 +- 4) x 10^-4 and (25 +12 -9 +- 5) x 10^-4, respectively. For eta' --> pi+ pi- pi0, this result probes the mechanism of isospin violation and the roles of pi0/eta/eta'-mixing and final state rescattering in strong decays. We also set upper limits on branching fractions for eta' decays to pi+ pi- mu+ mu-, 2(pi+ pi-), pi+ pi- 2pi0, 2(pi+ pi-)pi0, 3(pi+ pi-), and invisible final states.
description: 11 pages, available through http://www.lns.cornell.edu/public/CLNS/
Achieving adjustable elasticity with non-affine to affine transition
Creators: name: Shen, Xiangying
name: Fang, Chenchao
name: Jin, Zhipeng
name: Tong, Hua
name: Tang, Shixiang
name: Shen, Hongchuan
name: Xu, Ning
name: Lo, Jack Hau Yung
name: Xu, Xinliang
name: Xu, Lei
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: For various engineering and industrial applications it is desirable to realize mechanical systems with broadly adjustable elasticity to respond flexibly to the external environment. Here we discover a topology-correlated transition between affine and non-affine regimes in elasticity in both two- and three-dimensional packing-derived networks. Based on this transition, we numerically design and experimentally realize multifunctional systems with adjustable elasticity. Within one system, we achieve solid-like affine response, liquid-like non-affine response and a continuous tunability in between. Moreover, the system also exhibits a broadly tunable Poisson's ratio from positive to negative values, which is of practical interest for energy absorption and for fracture-resistant materials. Our study reveals a fundamental connection between elasticity and network topology, and demonstrates its practical potential for designing mechanical systems and metamaterials.
description: 10 pages, 5 figures
Planet Formation
Creators: name: Helled, Ravit
name: Morbidelli, Alessandro
Publisher: name: arXiv
Year: 2021
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Our galaxy is full with planets. We now know that planets and planetary systems are diverse and come with different sizes, masses and compositions, as well as various orbital architectures. Although there has been great progress in understanding planet formation in the last couple of decades, both observationally and theoretically, several fundamental questions remain unsolved. This might not be surprising given the complexity of the process that includes various physical and chemical processes, and spans huge ranges of length-scales, masses, and timescales. In addition, planet formation cannot be directly observed but has to be inferred by gluing together different pieces of information into one consistent picture. "How do planets form?" remains a fundamental question in modern astrophysics. In this review we list some of the key open questions in planet formation theory as well as the challenges and upcoming opportunities.
description: To appear as a book chapter in "ExoFrontiers: Big questions in exoplanetary science", Ed. N Madhusudhan (Bristol: IOP Publishing Ltd) AAS-IOP ebooks https://iopscience.iop.org/bookListInfo/aas-iop-astronomy
title: Front Matter, Foreword, Conference Organization, External Reviewers, Table of Contents
Creators: name: Ollinger, Nicolas
name: Vollmer, Heribert
Publisher: name: Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Year: 2016
Subjects: subject: Front Matter
subject: Foreword
subject: Conference Organization
subject: External Reviewers
subject: Table of Contents

description: Front Matter, Foreword, Conference Organization, External Reviewers, Table of Contents
description: LIPIcs, Vol. 47, 33rd Symposium on Theoretical Aspects of Computer Science (STACS 2016), pages 0:i-0:xvi
Nanostructure design for surface-enhanced Raman spectroscopy - prospects and limits
Creators: name: Xiao, Sanshui
name: Mortensen, Niels Asger
name: Jauho, Antti-Pekka
Publisher: name: arXiv
Year: 2008
Subjects: subject: Optics (physics.optics)
subject: Other Condensed Matter (cond-mat.other)
subject: Chemical Physics (physics.chem-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: Surface-enhanced Raman spectroscopy (SERS) allows single-molecule detection due to the strong field localization occurring at sharp bends or kinks of the metal-vacuum interface. An important question concerns the limits of the signal enhancement that can be achieved via a judicious design of the surface. By using a specific example of a technologically realizable nanopatterned surface, we demonstrate that while very high enhancement factors (~10^12) can be found for an ideal surface, these are unlikely to be achieved in laboratory samples, because even a minute, inevitable rounding-off strongly suppresses the enhancement, as well as shifts the optimal frequency. Our simulations indicate that the geometric enhancement factors are unlikely to exceed ~10^8 for real samples, and that it is necessary to consider the geometric uncertainty to reliably predict the frequency for maximum enhancement.
description: 12 pages including 5 figures
Experimental high-intensity three-photon entangled source
Creators: name: Lu, Huai-Xin
name: Zhang, Jun
name: Wang, Xiao-Qin
name: Li, Ying-De
name: Wang, Chun-Yan
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We experimentally realize a high-intensity three-photon Greenberger-Horne-Zeilinger (GHZ) entanglement source directly following the proposal by Rarity and Tapster [J. G. Rarity and P. R. Tapster, Phys. Rev. A 59, R35 (1999)]. The threefold coincidence rate can be more than 200 Hz with a fidelity of 0.811, and the intensity can be further improved with moderate fidelity degradation. The GHZ entanglement is characterized by testing the Bell-Mermin inequality and using an entanglement witness operator. To optimize the polarization-entangled source, we theoretically analyze the relationship between the mean photon number of the single-photon source and the probability of parametric down-conversion.
description: 4 pages, 4 figures
Propagation of compressional elastic waves through a 1-D medium with contact nonlinearities
Creators: name: Lombard, Bruno
name: Piraux, Joël
Publisher: name: arXiv
Year: 2008
Subjects: subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: Propagation of monochromatic elastic waves across cracks is investigated in 1D, both theoretically and numerically. Cracks are modeled by nonlinear jump conditions. The mean dilatation of a single crack and the generation of harmonics are estimated by a perturbation analysis, and computed by the harmonic balance method. With a periodic and finite network of cracks, direct numerical simulations are performed and compared with Bloch-Floquet's analysis.
description: Article following the fifth meeting of GdR 2501 (CNRS)
Physical time and other conceptual issues of QG on the example of LQC
Creators: name: Kaminski, Wojciech
name: Lewandowski, Jerzy
name: Pawlowski, Tomasz
Publisher: name: arXiv
Year: 2008
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Several conceptual aspects of quantum gravity are studied on the example of the homogeneous isotropic LQC model. In particular: $(i)$ The proper time of the co-moving observers is showed to be a quantum operator {and} a quantum spacetime metric tensor operator is derived. $(ii)$ Solutions of the quantum scalar constraint for two different choices of the lapse function are compared and contrasted. In particular it is shown that in case of model with masless scalar field and cosmological constant $Λ$ the physical Hilbert spaces constructed for two choices of lapse are the same for $Λ<0$ while they are significantly different for $Λ>0$. $(iii)$ The mechanism of the singularity avoidance is analyzed via detailed studies of an energy density operator, whose essential spectrum was shown to be an interval $[0,\rhoc]$, where $\rhoc\approx 0.41ρ_{\Pl}$. $(iv)$ The relation between the kinematical and the physical quantum geometry is discussed on the level of relation between observables.
description: Revtex4, 19 pages, 1 figure, revised to match the version published in CQG
Dynamical creation of entanglement versus disentanglement in a system of three - level atoms with vacuum - induced coherences
Creators: name: Derkacz, L.
name: Jakobczyk, L.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The dynamics of entanglement between three - level atoms coupled to the common vacuum is investigated. We show that the collective effects such as collective damping, dipole - dipole interaction and the cross coupling between orthogonal dipoles, play a crucial role in the process of creation of entanglement. In particular, the additional cross coupling enhances the production of entanglement. For the specific initial states we find that the effect of delayed sudden birth of entanglement, recently invented by Ficek and Tanas [Phys. Rev. A 77, o54301(2008)] in the case of two - level atoms, can also be observed in the system. When the initial state is entangled, the process of spontaneous emission causes destruction of correlation and its disentanglement. We show that the robustness of initial enatnglement against the noise can be changed by local operations performed on the state.
Do the photometric colors of Type II-P Supernovae allow accurate determination of host galaxy extinction?
Creators: name: Krisciunas, Kevin
name: Hamuy, Mario
name: Suntzeff, Nicholas B.
name: Espinoza, Juan
name: Gonzalez, David
name: Gonzalez, Luis
name: Gonzalez, Sergio
name: Koviak, Kathleen
name: Krzeminski, Wojtek
name: Morrell, Nidia
name: Phillips, Mark M.
name: Roth, Miguel
name: Thomas-Osip, Joanna
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present infrared photometry of SN 1999em, plus optical photometry, infrared photometry, and optical spectroscopy of SN 2003hn. Both objects were Type II-P supernovae. The V-[RIJHK] color curves of these supernovae evolved in a very similar fashion until the end of plateau phase. This allows us to determine how much more extinction the light of SN 2003hn suffered compared to SN 1999em. Since we have an estimate of the total extinction suffered by SN 1999em from model fits of ground-based and space-based spectra as well as photometry of SN 1999em, we can estimate the total extinction and absolute magnitudes of SN 2003hn with reasonable accuracy. Since the host galaxy of SN 2003hn also produced the Type Ia SN 2001el, we can directly compare the absolute magnitudes of these two SNe of different types.
description: 24 pages, 6 figures
A Pilot Survey for KX QSOs in the UKIDSS Ultra Deep Survey Field
Creators: name: Smail, Ian
name: Sharp, Rob
name: Swinbank, A. M.
name: Akiyama, M.
name: Ueda, Y.
name: Foucaud, S.
name: Almaini, O.
name: Croom, S.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We have undertaken a pilot survey for faint QSOs in the UKIDSS Ultra Deep Survey Field using the KX selection technique. These observations exploit the very deep near-infrared and optical imaging of this field from UKIRT and Subaru to select candidate QSOs based on their VJK colours and morphologies. We determined redshifts for 426 candidates using the AAOmega spectrograph on the AAT in service time. We identify 17 QSOs (M_B<= -23) in this pilot survey at z=1.57-3.29. We combine our sample with an X-ray selected sample of QSOs in the same field (a large fraction of which also comply with our KX selection) to constrain the surface density of QSOs with K<=20, deriving limits on the likely surface density of 85-150/deg^2. We use the good image quality available from our near-infrared imaging to detect a spatially extended component of the QSO light which probably represents the host galaxies. We also use our sample to investigate routes to improve the selection of KX QSOs at faint limits in the face of the significant contamination by compact, foreground galaxies. The brightest examples from our combined QSO sample will be used in conjunction with a large VLT VIMOS spectroscopic survey of high redshift galaxies in this region to study the structures inhabited by gas, galaxies and growing super-massive black holes at high redshifts in the UKIDSS UDS.
description: Accepted for publication in MNRAS
On the frequency, intensity and duration of starburst episodes triggered by galaxy interactions and mergers
Creators: name: Di Matteo, P.
name: Bournaud, F.
name: Martig, M.
name: Combes, F.
name: Melchior, A. -L.
name: Semelin, B.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We investigate the intensity enhancement and the duration of starburst episodes, triggered by major galaxy interactions and mergers. To this aim, we analyze two large statistical datasets of numerical simulations. These have been obtained using two independent and different numerical techniques to model baryonic and dark matter evolution, that are extensively compared for the first time. One is a Tree-SPH code, the other one is a grid-based N-body sticky-particles code. We show that, at low redshift, galaxy interactions and mergers in general trigger only moderate star formation enhancements. Strong starbursts where the star formation rate is increased by a factor larger than 5 are rare and found only in about 15% of major galaxy interactions and mergers. Merger-driven starbursts are also rather short-lived, with a typical duration of the activity of a few 10^8 yr. These conclusions are found to be robust, independent from the numerical techniques and star formation models. At higher redshifts where galaxies contain more gas, gas inflow-induced starbursts are neither stronger neither longer than their local counterparts. In turn, the formation of massive gas clumps, results of local Jeans instability that can occur spontaneously in gas-rich disks or be indirectly favored by galaxy interactions, could play a more important role in determining the duration and intensity of star formation episodes.
description: 22 pages, 28 figures, A&A accepted. High resolution version available at http://aramis.obspm.fr/~paola/SFR_frequency/
3D Structure from 2D Microscopy images using Deep Learning
Creators: name: Blundell, Benjamin J.
name: Sieben, Christian
name: Manley, Suliana
name: Rosten, Ed
name: Ch'ng, QueeLim
name: Cox, Susan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantitative Methods (q-bio.QM)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Image and Video Processing (eess.IV)
subject: FOS: Biological sciences
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Understanding the structure of a protein complex is crucial indetermining its function. However, retrieving accurate 3D structures from microscopy images is highly challenging, particularly as many imaging modalities are two-dimensional. Recent advances in Artificial Intelligence have been applied to this problem, primarily using voxel based approaches to analyse sets of electron microscopy images. Herewe present a deep learning solution for reconstructing the protein com-plexes from a number of 2D single molecule localization microscopy images, with the solution being completely unconstrained. Our convolutional neural network coupled with a differentiable renderer predicts pose and derives a single structure. After training, the network is dis-carded, with the output of this method being a structural model which fits the data-set. We demonstrate the performance of our system on two protein complexes: CEP152 (which comprises part of the proximal toroid of the centriole) and centrioles.
description: 32 Pages, 12 figures. Awaiting publication in 'Frontiers in Bioinformatics - Computational Bioimaging' - https://www.frontiersin.org/journals/bioinformatics
The Trigger System of the CMS Experiment
Creators: name: Felcini, Marta
Publisher: name: arXiv
Year: 2008
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We give an overview of the main features of the CMS trigger and data acquisition (DAQ) system. Then, we illustrate the strategies and trigger configurations (trigger tables) developed for the detector calibration and physics program of the CMS experiment, at start-up of LHC operations, as well as their possible evolution with increasing luminosity. Finally, we discuss the expected CPU time performance of the trigger algorithms and the CPU requirements for the event filter farm at start-up.
description: Presented at the 10th International Conference On Instrumentation For Colliding Beam Physics (INSTR08), 28 Feb - 5 Mar 2008, Novosibirsk, Russia
title: 1957-1958_AUBERT Claude_Essai sur l'habitat en zone saharienne, la rue galerie
Creators: name: Aubert, Claude
Publisher: name: NAKALA - https://nakala.fr (Huma-Num - CNRS)
Year: 2023
Subjects: subject: Diplôme d'architecte

description: Prix du meilleur diplôme décerné par la SADG.
OctoPath: An OcTree Based Self-Supervised Learning Approach to Local Trajectory Planning for Mobile Robots
Creators: name: Trasnea, Bogdan
name: Ginerica, Cosmin
name: Zaha, Mihai
name: Macesanu, Gigel
name: Pozna, Claudiu
name: Grigorescu, Sorin
Publisher: name: arXiv
Year: 2021
Subjects: subject: Robotics (cs.RO)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Autonomous mobile robots are usually faced with challenging situations when driving in complex environments. Namely, they have to recognize the static and dynamic obstacles, plan the driving path and execute their motion. For addressing the issue of perception and path planning, in this paper, we introduce OctoPath , which is an encoder-decoder deep neural network, trained in a self-supervised manner to predict the local optimal trajectory for the ego-vehicle. Using the discretization provided by a 3D octree environment model, our approach reformulates trajectory prediction as a classification problem with a configurable resolution. During training, OctoPath minimizes the error between the predicted and the manually driven trajectories in a given training dataset. This allows us to avoid the pitfall of regression-based trajectory estimation, in which there is an infinite state space for the output trajectory points. Environment sensing is performed using a 40-channel mechanical LiDAR sensor, fused with an inertial measurement unit and wheels odometry for state estimation. The experiments are performed both in simulation and real-life, using our own developed GridSim simulator and RovisLab's Autonomous Mobile Test Unit platform. We evaluate the predictions of OctoPath in different driving scenarios, both indoor and outdoor, while benchmarking our system against a baseline hybrid A-Star algorithm and a regression-based supervised learning method, as well as against a CNN learning-based optimal path planning method.
Optimal control gradient precision trade-offs: application to fast generation of DeepControl libraries for MRI
Creators: name: Vinding, Mads Sloth
name: Goodwin, David L.
name: Kuprov, Ilya
name: Lund, Torben Ellegaard
Publisher: name: arXiv
Year: 2021
Subjects: subject: Medical Physics (physics.med-ph)
subject: Image and Video Processing (eess.IV)
subject: FOS: Physical sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: We have recently demonstrated supervised deep learning methods for rapid generation of radiofrequency pulses in magnetic resonance imaging (https://doi.org/10.1002/mrm.27740, https://doi.org/10.1002/mrm.28667). Unlike the previous iterative optimization approaches, deep learning methods generate a pulse using a fixed number of floating-point operations - this is important in MRI, where patient-specific pulses preferably must be produced in real time. However, deep learning requires vast training libraries, which must be generated using the traditional methods, e.g. iterative quantum optimal control methods. Those methods are usually variations of gradient descent, and the calculation of the fidelity gradient of the performance metric with respect to the pulse waveform can be the most numerically intensive step. In this communication, we explore various ways in which the calculation of fidelity gradients in quantum optimal control theory may be accelerated. Four optimization avenues are explored: truncated commutator series expansions at zeroth and first order, a novel midpoint truncation scheme at first order, and the exact complex-step method. For the spin systems relevant to MRI, the first-order truncation is found to be sufficiently accurate, but also up to five times faster than the machine precision gradient. This makes the generation of training databases for the machine learning methods considerably more realistic.
description: The following article has been submitted to the Journal of Chemical Physics. After it is published, it will be found at https://aip.scitation.org/journal/jcp
NoSOCS in SDSS. I. Sample Definition and Comparison of Mass Estimates
Creators: name: Lopes, P. A. A.
name: de Carvalho, R. R.
name: Kohl-Moreira, J. L.
name: Jones, C.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We use Sloan Digital Sky Survey (SDSS) data to investigate galaxy cluster properties of systems first detected within DPOSS. With the high quality photometry of SDSS we derived new photometric redshifts and estimated richness and optical luminosity. For a subset of low redshift ($z \le 0.1$) clusters, we have used SDSS spectroscopic data to identify groups in redshift space in the region of each cluster, complemented with massive systems from the literature to assure the continuous mass sampling. A method to remove interlopers is applied, and a virial analysis is performed resulting in estimates of velocity dispersion, mass, and a physical radius for each low-$z$ system. We discuss the choice of maximum radius and luminosity range in the dynamical analysis, showing that a spectroscopic survey must be complete to at least M$^*+1$ if one wishes to obtain accurate and unbiased estimates of velocity dispersion and mass. We have measured X-ray luminosity for all clusters using archival data from RASS. For a smaller subset (twenty-one clusters) we selected temperature measures from the literature and estimated mass from the M-T$_X$ relation, finding that they show good agreement with the virial estimate. However, these two mass estimates tend to disagree with the caustic results. We measured the presence of substructure in all clusters of the sample and found that clusters with substructure have virial masses higher than those derived from T$_X$. This trend is not seen when comparing the caustic and X-ray masses. That happens because the caustic mass is estimated directly from the mass profile, so it is less affected by substructure.
description: 21 pages, 17 figures, 5 tables, Accepted to MNRAS
Can the Copernican principle be tested by cosmic neutrino background?
Creators: name: Jia, Junji
name: Zhang, Hongbao
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The Copernican principle, stating that we do not occupy any special place in our universe, is usually taken for granted in modern cosmology. However recent observational data of supernova indicate that we may live in the under-dense center of our universe, which makes the Copernican principle challenged. It thus becomes urgent and important to test the Copernican principle via cosmological observations. Taking into account that unlike the cosmic photons, the cosmic neutrinos of different energies come from the different places to us along the different worldlines, we here propose cosmic neutrino background as a test of the Copernican principle. It is shown that from the theoretical perspective cosmic neutrino background can allow one to determine whether the Copernican principle is valid or not, but to implement such an observation the larger neutrino detectors are called for.
description: JHEP style, 10 pages, 4 figures, version to appear in JCAP
Quantum decoherence and gravitational waves
Creators: name: Jaekel, Marc-Thierry
name: Lamine, Brahim
name: Lambrecht, Astrid
name: Reynaud, Serge
name: Neto, Paulo Maia
Publisher: name: arXiv
Year: 2008
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The quite different behaviors exhibited by microscopic and macroscopic systems with respect to quantum interferences suggest the existence of a borderline beyond which quantum systems loose their coherences and can be described classically. Gravitational waves, generated within our galaxy or during the cosmic expansion, constitute a universal environment susceptible to lead to such a quantum decoherence mechanism. We assess this idea by studying the quantum decoherence due to gravitational waves on typical microscopic and macoscopic systems, namely an atom interferometer (HYPER) and the Earth-Moon system. We show that quantum interferences remain unaffected in the former case and that they disappear extremely rapidly in the latter case. We obtain the relevant parameters which, besides the ratio of the system's mass to Planck mass, characterize the loss of quantum coherences.
description: 7 pages
Coherence versus reliability of stochastic oscillators with delayed feedback
Creators: name: Goldobin, Denis S.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: For noisy self-sustained oscillators, both reliability, stability of a response to a noisy driving, and coherence understood in the sense of constancy of oscillation frequency belong to the main characteristics. Though the both characteristics and techniques for controlling them received great attention of researchers, owing to their importance for neurons, lasers, clocks, electric generators, etc., these characteristics were previously considered separately. In this paper, strong quantitative relation between coherence and reliability is revealed for a limit cycle oscillator subject to a weak noisy driving and a linear delayed feedback, a convectional control tool. Analytical findings are verified and enriched with a numerical simulation for the Van der Pol-Duffing oscillator.
description: 4 pages, 5 figures
Sharpening the Tip of the Red Giant Branch
Creators: name: Madore, Barry F.
name: Mager, Violet
name: Freedman, Wendy L.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We introduce a modified detection method for measuring the luminosity of the tip of the red giant branch (TRGB) by introducing the composite magnitude T = I - beta [(V-I)_o - 1.50], where beta is the slope of the tip magnitude as a function of color (or metallicity). The method is specifically designed to account for known systematics due to metallicity. In doing so, this simple transformation does away with arbitrary color selections in measuring the tip, and thereby significantly boosts the population of resolved stars that go into defining the TRGB distance. Moreover this method coincidentally reduces the impact of reddening on the true modulus as well as its final uncertainty.
description: 9 pages, 6 figures; to be published in the Astrophysical Journal
The use of AR elements in the study of foreign languages at the university
Creators: name: Tarasenko, Rostyslav
name: Amelina, Svitlana
name: Kazhan, Yuliya
name: Bondarenko, Olga
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computers and Society (cs.CY)
subject: FOS: Computer and information sciences

description: The article deals with the analysis of the impact of the using AR technology in the study of a foreign language by university students. It is stated out that AR technology can be a good tool for learning a foreign language. The use of elements of AR in the course of studying a foreign language, in particular in the form of virtual excursions, is proposed. Advantages of using AR technology in the study of the German language are identified, namely: the possibility of involvement of different channels of information perception, the integrity of the representation of the studied object, the faster and better memorization of new vocabulary, the development of communicative foreign language skills. The ease and accessibility of using QR codes to obtain information about the object of study from open Internet sources is shown. The results of a survey of students after virtual tours are presented. A reorientation of methodological support for the study of a foreign language at universities is proposed. Attention is drawn to the use of AR elements in order to support students with different learning styles (audio, visual, kinesthetic).
description: 14 pages, 5 figures, 1 table
On the Time-Modulation of the beta^+$-Decay Rate of H-like 140Pr58+ Ion
Creators: name: Ivanov, A. N.
name: Kryshen, E. L.
name: Pitschmann, M.
name: Kienle, P.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: According to recent experimental data at GSI, the rates of the number of daughter ions, produced by the nuclear K-shell electron capture (EC) decays of the H-like ions 140Pr58+ and 142Pm60+, are modulated in time with periods T_(EC) simeq 7 s and amplitudes a_(EC) simeq 0.20. We study a possible time-dependence of the nuclear positron (beta^+) decay rate of the H-like 140Pr58+. We show that the time-dependence of the beta^+ decay rate of the H-like 140Pr58+ ion as well as any H-like heavy ions cannot be observed. This result can be used as a prediction for future analysis of the time-dependence of the beta^+ decay rates of the H-like heavy ions 140Pr58+ and 142Pm60+ at GSI for the test of the measuring method.
description: 4 pages, 3 figures
ESTUDO COMPARATIVO DE COBERTURAS EM PROL DA EFICIÊNCIA ENERGÉTICA
Creators: name: Thaylla Martírios SANTOS
name: Pedro Henrick Venâncio de SOUZA
name: Mariana Matos ARANTES
Publisher: name: Zenodo
Year: 2024
Subjects: Eficiência Energética
Telhado
Temperatura

description: RESUMO

Com o propósito de melhorar a eficiência energética das edificações devido ao crescente consumo de energia elétrica, as análises comparativas como um meio eficaz de comprovação estão se tornando cada vez mais frequentes. Além disso, há um grande aumento no investimento em busca de tecnologias que aumentam o desempenho energético desses materiais sem que haja mudanças na sua composição originária. Os telhados são o principal meio de absorção energética, por isso devem ser compostos por materiais com uma baixa condutividade térmica. Para o desenvolvimento deste trabalho foram escolhidos 4 dos principais tipos de telhas mais utilizados na cidade de Araguaína- TO, para que fossem verificadas suas características e posteriormente passaram por uma análise experimental em um protótipo de acondicionamento que foi posicionado a céu aberto com a ajuda de dois termômetros digitais, sendo um na parte inferior e outro no exterior para coletar os dados de temperatura. Os resultados obtidos foram comparados entre si e foi possível identificar qual possui a melhor eficiência energética, ocasionando melhoria térmica nas edificações.
First detection of hard X-ray photons in the soft X-ray transient Narrow-Line Seyfert 1 galaxy WPVS 007: The X-ray photon distribution observed by Swift
Creators: name: Grupe, Dirk
name: Leighly, Karen M.
name: Komossa, Stefanie
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report on the first detection of hard X-ray photons (E>2.5 keV) in the X-ray transient Narrow-Line Seyfert 1 galaxy WPVS 007 which was the AGN with the softest X-ray spectrum during the ROSAT All-Sky Survey. The AGN is clearly detected at a level of about 2 x 10^{-17} W m^{-2} in the observed 0.3-10.0 keV band by Swift in a 50 ks observation in 2007 September. For the first time since the ROSAT All-Sky Survey observation in 1990 it was possible to derive an X-ray photon distribution by adding together all Swift observations that have been performed so far (85.5 ks in total). This photon distribution is consistent with an X-ray spectrum of an AGN with a partial covering absorber with a column density in the order of ~ 1 x 10^{23} cm^{-2} and a covering fraction of about 90%. A comparison with the 2002 Chandra data suggests that WPVS 007 has become brighter by a factor of about 4. The Swift data also suggest that the absorber which is causing the current low-state may have started to disappear. This disappearance is indicated by a significant change in the hardness ratio from a very soft X-ray state during the 2005 October to 2007 January observations to a rather hard X-ray state in the 2007 September observations. In the UV, WPVS 007 seems to become fainter by up to 0.5 mag over the last two years. The optical to X-ray spectral slope derived from the spectral energy distribution is alpha-ox=2.5 which classifies WPVS 007 as an X-ray weak AGN. After correcting for reddening and X-ray absorption, alpha-ox becomes 1.9 and the luminosity in the Big-Blue-Bump is log LBBB=37.7 [W], which translates into an Eddington ratio L/LEdd ~ 1.0.
description: Accepted for publication in the Astronomical Journal, scheduled for December 2008, 8 pages, 3 figures, 3 tables
A weighted planar stochastic lattice with scale-free, small-world and multifractal properties
Creators: name: Mitra, Tushar
name: Hassan, Md. Kamrul
Publisher: name: arXiv
Year: 2021
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: We investigate a class of weighted planar stochastic lattice (WPSL1) created by random sequential nucleation of seed from which a crack is grown parallel to one of the sides of the chosen block and ceases to grow upon hitting another crack. It results in the partitioning of the square into contiguous and non-overlapping blocks. Interestingly, we find that the dynamics of WPSL1 is governed by infinitely many conservation laws and each of the conserved quantities, except the trivial conservation of total mass or area, is a multifractal measure. On the other hand, the dual of the lattice is a scale-free network as its degree distribution exhibits a power-law $P(k)\sim k^{-γ}$ with $γ=4.13$. The network is also a small-world network as we find that (i) the total clustering coefficient $C$ is high and independent of the network size and (ii) the mean geodesic path length grows logarithmically with $N$. Besides, the clustering coefficient $C_k$ of the nodes which have degree $k$ decreases exactly as $2/(k-1)$ revealing that it is also a nested hierarchical network.
description: 10 pages, 9 captioned figures
SDSSJ084539.17+225728.0: the first DBZ white dwarf with a metal-rich gaseous debris disc
Creators: name: Gaensicke, B. T.
name: Koester, D.
name: Marsh, T. R.
name: Rebassa-Mansergas, A.
name: Southworth, J.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report the discovery of a third white dwarf hosting a gaseous debris disc, SDSSJ084539.17+225728.0. The typical double-peaked CaII 8498,8542,8662A emission lines can be modelled in terms of a Keplerian gas disc with a radial extent from ~0.5Rsun to ~1.0. The effective temperature of SDSS0845+2257, Teff=18600+-500K, is comparable to the two other white dwarfs with gaseous discs, SDSS1043+0855 and SDSS1228+1040, and hence substantially hotter than the bulk of white dwarfs where dusty debris discs were identified through the presence of infrared excess flux. This may suggest that the conditions to produce emission lines from debris discs in the optical wavelength range are only met for a relatively narrow range in Teff. The observed asymmetry in the line profiles indicates a substantial eccentricity in the disc. Two spectra obtained four years apart reveal a significant change in the shapes and equivalent widths of the line profiles, implying that the circumstellar disc evolves on relatively short time scales. In contrast to SDSS1043+0855 and SDSS1228+1040, SDSS0845+2257 has a helium-dominated atmosphere. We detect photospheric absorption lines of He, Ca, Mg, and Si in the Sloan Digital Sky Survey spectrum, and hence classify SDSS0845+2257 as DBZ white dwarf. The abundances for the three metals determined from model atmosphere fits are Ca/He~1.3x10^-7, Mg/He~6.0x10^-6, and Si/He~8.0x10^-6. From the non-detection of Halpha we derive H/He<3x10^-5, which implies that the hydrogen-to-metal abundance ratio of the circumstellar material is >~1000 times lower than in the Sun. This lends strong support to the hypothesis that the gaseous and dusty debris discs found around roughly a dozen white dwarfs originate from the disruption of rocky planetary material.
description: MNRAS Letters in press
Remarks on inverse electrodynamics
Creators: name: Gaete, Patricio
name: Helayël-Neto, José A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study physical aspects for a new nonlinear electrodynamics (inverse electrodynamics). It is shown that this new electrodynamics displays the vacuum birefringence phenomenon in the presence of external magnetic field, hence we compute the bending of light. Afterwards we compute the lowest-order modification to the interaction energy within the framework of the gauge-invariant but path-dependent variables formalism. Our calculations show that the interaction energy contains a long-range (${1 \mathord{\left/ {\vphantom {1 {r^5}}} \right.\kern-\nulldelimiterspace} {r^5}}$-type) correction to the Coulomb potential.
description: 10 pages
Momentum-space analysis of multipartite entanglement at quantum phase transitions
Creators: name: Anfossi, Alberto
name: Giorda, Paolo
name: Montorsi, Arianna
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We investigate entanglement properties at quantum phase transitions of an integrable extended Hubbard model in the momentum space representation. Two elementary subsystems are recognized: the single mode of an electron, and the pair of modes (electrons coupled through the eta-pairing mechanism). We first detect the two/multi-partite nature of each quantum phase transition by a comparative study of the singularities of Von Neumann entropy and quantum mutual information. We establish the existing relations between the correlations in the momentum representation and those exhibited in the complementary picture: the direct lattice representation. The presence of multipartite entanglement is then investigated in detail through the Q-measure, namely a generalization of the Meyer-Wallach measure of entanglement. Such a measure becomes increasingly sensitive to correlations of a multipartite nature increasing the size of the reduced density matrix. In momentum space, we succeed in obtaining the latter for our system at arbitrary size and we relate its behaviour to the nature of the various QPTs.
description: 8 pages, 4 figures
Two dark matter components in N_{DM}MSSM and dark matter extension of the minimal supersymmetric standard model and the high energy positron spectrum in PAMELA/HEAT data
Creators: name: Huh, Ji-Haeng
name: Kim, Jihn E.
name: Kyae, Bumseok
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present the dark matter (DM) extension (by N) of the minimal supersymmetric standard model to give the recent trend of the high energy positron spectrum of the PAMELA/HEAT experiments. If the trend survives by future experiments, the MSSM needs to be extended. Here, we minimally extend the MSSM with one more DM component N together with a heavy lepton E, and introduce the coupling e_R E_R^c N_R. This coupling naturally appears in the flipped SU(5) GUT models. This N_{DM}MSSM contains the discrete symmetry Z_6, and for some parameter ranges there result two DM components. For the MSSM fields, the conventional R-parity, which is a subgroup of Z_6, is preserved. We also present the needed parameter ranges of these additional particles.
LHAASO discovery of highest-energy photons towards new physics
Creators: name: Li, Chengyi
name: Ma, Bo-Qiang
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Ultrahigh-energy photons up to 1.4 peta-electronvolts have been observed by new cosmic-ray telescope in China -- a hint that Lorentz invariance might break down at the Planck-scale level.
description: 3 pages, 1 figure, final version for publication