cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
3D-printed variable stiffness tissue scaffolds for potential meniscus repair
Creators: name: A. Murphy, Caroline
name: Serafin, Aleksandra
name: Cengiz, Ibrahim Fatih
name: Reis, Rui L.
name: Oliveira, Joaquim Miguel
name: Collins, Maurice
Publisher: name: University of Limerick
Year: 2024
Subjects: classificationCode: 40
subject: Engineering
classificationCode: 42
subject: Health sciences
subject: FOS: Health sciences

description: The treatment of meniscus injuries has recently shifted toward the field of tissue engineering (TE). In this work, bovine menisci were characterized, and the regionally-dependent mechanical properties were analyzed. Three-dimensional (3D) printing technology was employed to produce a scaffold that mimicked the mechanical properties of the meniscus. A polycaprolactone (PCL) meniscus scaffold was 3D printed, allowing for the deposition of fibers mimicking the internal architecture of the native meniscus, while achieving regional and variable mechanical stiffness, varying from 2.74 to 0.88 MPa. The PCL scaffold was infiltrated with extracellular matrix (ECM)-like hydrogels composed of gelatin methacrylate (GelMA) and glycosaminoglycans (GAGs), such as hyaluronic acid (HA) and chondroitin sulfate (CS), and subsequently freeze-dried. Human mesenchymal stem cells were seeded onto the scaffolds, and the infiltrated cells were observed to produce ECM components of the native meniscus. Collagen and GAGs production was successfully established. The synthesis of a new matrix reportedly enhances the mechanical properties of the hydrogel over time. Additionally, the circumferential PCL fibers within the scaffold guided the newly synthesized matrix, facilitating replication of the native tissue structure. These results indicate that the ECM-infiltrated 3D-printed PCL scaffold is a promising solution for meniscus repair.
Investigation of artificial domains realised by local gallium focused ion beam (FIB) modification of Pt/Co/Pt trilayer structures
Creators: name: Aziz, A.
name: Bending, S. J.
name: Robert, H.
name: Crampin, S.
name: Heard, P. J.
name: Marrows, C. H.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We present the results of experimental investigations of magnetic switching and magnetotransport in a new generation of magnetic devices containing artificially patterned domains. Our devices are realised by locally reducing the coercive field of a perpendicularly magnetised Pt (3.5 nm)/Co (0.5 nm)/Pt (1.6 nm) trilayer structure using a gallium focused ion beam (FIB). Artificial domain walls are created at the interfaces between dosed and undosed regions when an external magnetic field switches the former but not the latter. We have exploited this property to create stripe-like domains with widths down to sub-micron lengthscales, separated by undosed regions. Using the extraordinary Hall effect to monitor the local magnetisation we have investigated the reversal dynamics of these artificial domains by measuring major and minor hysteresis loops. The coercive field of regions irradiated with identical doses systematically increases as their size decreases. In the lower branch of minor loops, reversal is seen to occur via a few large Barkhausen events. Preliminary measurements of transport across domain walls reveal a positive domain wall resistance, that does not change sign from 4.2 K to 300 K.
A weakness in strong localization for Sinai's walk
Creators: name: Shi, Zhan
name: Zindy, Olivier
Publisher: name: arXiv
Year: 2006
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 60K37, 60G50, 60J55 (Primary)

description: Sinai's walk is a recurrent one-dimensional nearest-neighbor random walk in random environment. It is known for a phenomenon of strong localization, namely, the walk spends almost all time at or near the bottom of deep valleys of the potential. Our main result shows a weakness of this localization phenomenon: with probability one, the zones where the walk stays for the most time can be far away from the sites where the walk spends the most time. In particular, this gives a negative answer to a problem of Erdős and Révész [Mathematical Structures--Computational Mathematics--Mathematical Modelling 2 (1984) 152--157], originally formulated for the usual homogeneous random walk.
description: Published at http://dx.doi.org/10.1214/009117906000000863 in the Annals of Probability (http://www.imstat.org/aop/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Rise of the Machines? Intraday High-Frequency Trading Patterns of Cryptocurrencies
Creators: name: Petukhina, Alla A.
name: Reule, Raphael C. G.
name: Härdle, Wolfgang Karl
Publisher: name: arXiv
Year: 2020
Subjects: subject: Trading and Market Microstructure (q-fin.TR)
subject: FOS: Economics and business

description: This research analyses high-frequency data of the cryptocurrency market in regards to intraday trading patterns related to algorithmic trading and its impact on the European cryptocurrency market. We study trading quantitatives such as returns, traded volumes, volatility periodicity, and provide summary statistics of return correlations to CRIX (CRyptocurrency IndeX), as well as respective overall high-frequency based market statistics with respect to temporal aspects. Our results provide mandatory insight into a market, where the grand scale employment of automated trading algorithms and the extremely rapid execution of trades might seem to be a standard based on media reports. Our findings on intraday momentum of trading patterns lead to a new quantitative view on approaching the predictability of economic value in this new digital market.
Phylogenetic analyses of Penicillium isolated from psychrophilic environments
Creators: name: Visagie, Cobus
name: Overy, Dave
Publisher: name: University of Pretoria
Year: 2024
Subjects: classificationCode: 310705
subject: Mycology

description: DNA sequence alignments, nucleotide substitution models and treefiles obtained during the phylogenetic analyses used in the publication of the manuscript 'Chemodiversity of Penicillium isolated from psychrophilic environments, including ten new species'.
Hidden Trigger for the Giant Starburst Arc in M 83?
Creators: name: Diaz, Ruben J.
name: Dottori, Horacio
name: Aguero, Maria P.
name: Mediavilla, Evencio
name: Rodrigues, Irapuan
name: Mast, Damian
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The huge star formation events that occur at some galactic centers do not provide enough clues as to their origin, since the morphological signatures of the triggering mechanism are smeared out in the timescale of a few orbital revolutions of the galaxy core. Our high spatial resolution three-dimensional near-infrared spectroscopy for the first time reveals that a previously known hidden mass concentration is located exactly at the youngest end of a giant star-forming arc. This location, the inferred average cluster ages, and the dynamical times clearly indicate that the interloper has left behind a spur of violent star formation in M 83, in a transient event lasting less than one orbital revolution. The study of the origin (bar funneling or cannibalized satellite) and fate (black hole merging or giant stellar cluster) of this system could provide clues to the question of core growing and morphological evolution in grand-design spiral galaxies. In particular, our TreeSPH numerical modeling suggests that the two nuclei could coalesce, forming a single massive core in about 60 million years or less.
description: 18 pages, including 4 figures (3 in color). The Astrophysical Journal, in press
Η άμυνα και ιδίως οι κοινωνικοηθικοί περιορισμοί αυτής
Creators: name: Θεοφανίδης, Ευστάθιος Ιωάννη
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: Άμυνα
Κοινωνικοηθικοί
Περιορισμοί
defense
restrictions
socio-moral

description: Σκοπός της διατριβής ήταν η μελέτη του δικαιώματος της άμυνας ως του σπουδαιότερου λόγου άρσης του άδικου χαρακτήρα μιας αξιόποινης πράξης όπως τυποποιείται στο άρθρο 22 του Ποινικού Κώδικα. Ειδικότερα η μελέτη εστιάζει στη θεωρία των “κοινωνικοηθικών” περιορισμών όπως αυτή αναπτύχθηκε στους κόλπους της ποινικής επιστήμης. Η ανωτέρω θεωρία πραγματεύεται καταστάσεις στις οποίες το δικαίωμα άμυνας ως απάντηση σε μια άδικη επίθεση δεν ασκείται απεριόριστα αλλά υπακούει σε όρια που θέτει η κοινωνική ηθική. Με τον τρόπο αυτό η αντίδραση στο άδικο συμβιβάζεται τόσο με την έννοια της κοινωνικής αλληλεγγύης όσο και με την συνταγματική αρχή της αναλογικότητας.
description: The aim of the present thesis was the study of the right of defense which is the most important reason of justification of the penal offences, as the particular right has been legislated in the Ar.22 Penal Code. Specifically, the present diplomatic work focuses especially on the theory of the so-called “socio-moral limitations” of the defense right, as developed in the framework of penal science. The particular theory deals with situations where the right of defense consisting the response to an unfair attack, may not be unlimited exercised, but obeys to restrictions set by social morality. In this way, the reaction to the injustice is compatible with both the concept of social solidarity and with the constitutional principle of proportionality.
Hydrodynamic effects in the capture of rod-like molecules by a nanopore
Creators: name: Waszkiewicz, Radost
name: Lisicki, Maciej
Publisher: name: arXiv
Year: 2020
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Biological Physics (physics.bio-ph)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: In the approach of biomolecules to a nanopore, it is essential to capture the effects of hydrodynamic anisotropy of the molecules and the near-wall hydrodynamic interactions which hinder their diffusion. We present a detailed theoretical analysis of the behaviour of a rod-like molecule attracted electrostatically by a charged nanopore. We first estimate the time scales corresponding to Brownian and electrostatic translations and reorientation. We find that Brownian motion becomes negligible at distances within the pore capture radius, and numerically determine the trajectories of the nano-rod in this region to explore the effects of anisotropic mobility. This allows us to determine the range of directions from the pore in which hydrodynamic interactions with the boundary shape the approach dynamics and need to be accounted for in detailed modelling.
description: Accepted in J. Phys.: Condens. Matter (2020)
Distant Jupiter family Comet P/2011 P1 (McNaught)
Creators: name: Korsun, Pavlo
name: Ivanova, Oleksandra
name: Afanasiev, Viktor
name: Kulyk, Irina
Publisher: name: arXiv
Year: 2021
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: The spectra and images obtained through broadband BVR filters for Jupiter famaly comet P/2011 P1 were analyzed. We observed the comet on November 24, 2011, when its heliocentric distance was 5.43 AU. Two dimensional long slit spectra and photometric images were obtained using the focal reducer SCORPIO attached to the prime focus of the 6-m telescope BTA (SAO RAS, Russia). The spectra cover the wavelength range of 4200-7000 Å. No emissions of C2 and CO+, which are expected in this wavelength region, were detected above 3 sigma level. An upper limit in gas production rate of C2 is expected to be 1.1*10^24 mol*s^-1. The continuum shows a reddening effect with the normalized gradient of reflectivity along dispersion of 5.1% per 1000 Å. The color indices (B-V)=0.89 and (V-R) = 0.42 for the nucleus region or (B-V)=0.68 and (V-R)=0.39 for the coma region, which are derived from the photometric data, also evidence that the color of the cometary nucleus and dust are redder with respect to the Sun. The dust coma like a spiral galaxy adge on was fitted using a Monte Carlo model.
description: 8 pages, 6 figures, 6 tables
On the reliability of CIV 1549 as an abundance indicator for high redshift star-forming galaxies
Creators: name: Crowther, P. A.
name: Prinja, R. K.
name: Pettini, M.
name: Steidel, C. C.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We reconsider the use of the equivalent width of CIV 1549, EW(CIV), as an indicator of the oxygen abundance in star-forming galaxies, as proposed by Heckman et al. for nearby starbursts. We refine the local calibration of EW(CIV) vs. log (O/H) by using a restricted wavelength window which minimises blending with interstellar absorption lines. When applied to the stellar component only of the complex CIV 1549 features in two high redshift galaxies with good quality spectra, MS1512-cB58 (z = 2.7268) and Q1307-BM1163 (z = 1.4105), the local calibration gives values of the oxygen abundance which are in good agreement with other metallicity determinations based on nebular emission and interstellar absorption lines. Our main conclusion is that for this method to give reliable results at high redshifts, it should only be used on data of sufficiently high spectral resolution (R > 1000) for stellar and interstellar CIV components to be clearly separated. Oxygen abundances will be systematically overestimated if the local calibration is applied to spectra of high-z galaxies obtained with the low resolving powers (R ~ 200-300) of many current wide field surveys. It will also be necessary to understand better the causes of the scatter in the local relation, before we can be confident of inferences from it at high z.
description: 7 pages, 4 figures, accepted for MNRAS (revision fixes up wrong fig.2)
Magnetic fields in star-forming systems (II): examining dust polarization, the Zeeman effect, and the Faraday rotation measure as magnetic field tracers
Creators: name: Reissl, Stefan
name: Stutz, Amelia M.
name: Klessen, Ralf S.
name: Seifried, Daniel
name: Walch, Stefanie
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The degree to which the formation and evolution of clouds and filaments in the interstellar medium is regulated by magnetic fields remains an open question. Yet the fundamental properties of the fields (strength and 3D morphology) are not readily observable. We investigate the potential for recovering magnetic field information from dust polarization, the Zeeman effect, and the Faraday rotation measure ($RM$) in a SILCC-Zoom magnetohydrodynamic (MHD) filament simulation. The object is analyzed at the onset of star formation, and it is characterized by a line-mass of about M/L $\sim 63\ M_{\odot}\ pc^{-1}$ out to a radius of $1\,$pc and a kinked 3D magnetic field morphology. We generate synthetic observations via POLARIS radiative transfer (RT) post-processing, and compare with an analytical model of helical or kinked field morphology to help interpreting the inferred observational signatures. We show that the tracer signals originate close to the filament spine. We find regions along the filament where the angular-dependency with the line-of-sight (LOS) is the dominant factor and dust polarization may trace the underlying kinked magnetic field morphology. We also find that reversals in the recovered magnetic field direction are not unambiguously associated to any particular morphology. Other physical parameters, such as density or temperature, are relevant and sometimes dominant compared to the magnetic field structure in modulating the observed signal. We demonstrate that the Zeeman effect and the $RM$ recover the line-of-sight magnetic field strength to within a factor 2.1 - 3.4. We conclude that the magnetic field morphology may not be unambiguously determined in low-mass systems by observations of dust polarization, Zeeman effect, or $RM$, whereas the field strengths can be reliably recovered.
description: 22 pages, 17 figures, 3 tables
Following unnamed rivers and ruminating on teaching as vocation
Creators: name: Scott, Jeanette Elynn MacArthur
Publisher: name: University of British Columbia
Year: 2009

description: The research which is reported in this text is probably best described as an interpretive inquiry which situates itself in the space between theory and practice and which explores the questions: What do teachers' stories tell us about the call of teaching? and How does drama help teachers to remember and to tell their stories? Originally imagined as a phenomenological study of teaching as a vocation, this project has slipped to the Acheron1 edge of academic research and, in so doing, it has been reborn(e) as a tapestry of words. The fabric of the text is an intertwining of threads of ideas, feelings and imaginings, a pulling out and a weaving in of bits of the tangled and worn, a playing with different textures and different tones. The common threads of the warp, consisting of a series of personal ruminations on the emergence, the development, the completion and the implications of a research project, lend a unity and a strength to the piece. The weft, which incorporates both old yarns and new y(e)arns, is intentionally a coarse interweaving of dark and light, common and exotic fibres. All of the parts are connected as in a Celtic knot with the text of the drama, written as a presentation of the data that were collected, at the centre. In part, drawing upon images of the arts; in part, borrowing from Zen Buddhism the metaphor of searching for the bull as the search for the eternal truth, the whole work suggests that the call of teaching emerges from a polyphony of voices, that it is heard and responded to in a similar contrapuntality of difference. In keeping with the tradition of an hermeneutic circle, the parts are seen within the whole and the whole within the parts. The fabric, as such, is a loose weave so that spaces are provided wherein the reader is invited to read in and write out or write in and read out whatever questions or answers that s/he intuits hidden among the threads.
A box-covering algorithm for fractal scaling in scale-free networks
Creators: name: Kim, J. S.
name: Goh, K. -I.
name: Kahng, B.
name: Kim, D.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: A random sequential box-covering algorithm recently introduced to measure the fractal dimension in scale-free networks is investigated. The algorithm contains Monte Carlo sequential steps of choosing the position of the center of each box, and thereby, vertices in preassigned boxes can divide subsequent boxes into more than one pieces, but divided boxes are counted once. We find that such box-split allowance in the algorithm is a crucial ingredient necessary to obtain the fractal scaling for fractal networks; however, it is inessential for regular lattice and conventional fractal objects embedded in the Euclidean space. Next the algorithm is viewed from the cluster-growing perspective that boxes are allowed to overlap and thereby, vertices can belong to more than one box. Then, the number of distinct boxes a vertex belongs to is distributed in a heterogeneous manner for SF fractal networks, while it is of Poisson-type for the conventional fractal objects.
description: 12 pages, 11 figures, a proceedings of the conference, "Optimization in complex networks." held in Los Alamos
Bericht des Nationalen Referenzzentrums für Masern, Mumps, Röteln für die Jahre 2017 und 2018
Creators: name: Mankertz, Annette
name: Santibanez, Sabine
name: Bauer, Agnieszka
name: Friedrich, Nicole
Publisher: name: Robert Koch-Institut
Year: 2019
Subjects: subject: Masern
subject: Mumps
subject: Röteln
subject: Genotypen
subject: molekulare Surveillance
subject: 610 Medizin und Gesundheit

description: Für Deutschland wurden in den Jahren 2017 und 2018 für Masern und Mumps mittlere Erkrankungszahlen, für Röteln niedrige Fallzahlen nach IfSG gemeldet. Die Einsendezahlen lagen für Masern und Mumps bei mehreren hundert Einsendungen, für Röteln wurden jeweils weniger als 100 Proben erhalten. Die Bestätigungsraten sind im Hinblick auf die Schwierigkeit der Diagnose (bei eher unspezifischen Symptomen für alle drei Erreger) von Interesse. Für Masern lag sie im NRZ MMR mit 50 % höher als in den letzten Jahren, wohingegen sie für Mumps und Röteln niedrig ausfiel. Wie im Epidemiologischen Bulletin 32/33 weiter berichtet wird, hat die Zahl der weltweit nachgewiesenen Genotypen bei Masern sich in den letzten Jahren drastisch verringert: Von den seit Beginn der molekularen Surveillance entdeckten 24 Genotypen zirkulierten in den Jahren 2017–2018 nur noch drei längerfristig (B3, D8 und H1). In Deutschland traten im gleichen Zeitraum ausschließlich die Genotypen B3 bzw. D8 auf.
A longitudinal study of the effects of instruction on the development of article use by adult Japanese ESL learners
Creators: name: Mellow, John Dean
Publisher: name: University of British Columbia
Year: 2009

description: This dissertation investigates the effects and value of instructional activities for improving second language use of English articles. After reviewing a number of issues concerning pedagogical, linguistic, psycholinguistic, and internal validity, this study presents the results of eight longitudinal time-series case studies of adult Japanese learners of English residing in Vancouver, Canada, four of whom received grammatical explanations, input processing activities, and output practice activities regarding English article use. Learner development was assessed on three different narrative retelling tasks (spoken, written, and cloze) and the production was analysed with reference to specific contexts of use, indicating the form-function mappings that comprised the learners' interlanguage knowledge. The results indicated that the learners' interlanguage production exhibited (a) the anticipated task variation, with greater suppliance of the on tasks that allowed greater attention to form, and (b) the anticipated discoursal variation, with the supplied more consistently when it was primed as a redundant element on the written task and with the supplied less consistently when it was efficiently deleted as a redundant element on the spoken task. The results also indicated the variable nature of individual development and the value of assessing development longitudinally on different tasks. Importantly, the results indicated that the learners improved or continued improving after instruction, and strongly suggested that instruction can cause automatization of interlanguage knowledge. This finding suggests that form-focused instruction may be valuable for second language learning, and that pedagogical positions opposing form-focused instruction may need to be revised or abandoned.
On the Integrability of a Class of Nonlinear Dispersive Wave Equations
Creators: name: Ivanov, Rossen I.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: FOS: Physical sciences

description: We investigate the integrability of a class of 1+1 dimensional models describing nonlinear dispersive waves in continuous media, e.g. cylindrical compressible hyperelastic rods, shallow water waves, etc. The only completely integrable cases coincide with the Camassa-Holm and Degasperis-Procesi equations.
description: 8 pages
Pseudo-time-reversal-symmetry-protected topological Bogoliubov excitations of Bose-Einstein condensates in optical lattices
Creators: name: Wang, Junsen
name: Zheng, Wei
name: Deng, Youjin
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Bogoliubov excitations of Bose-Einstein condensates in optical lattices may possess band topology in analogous to topological insulators in class AII of fermions. Using the language of the Krein-space theory, this topological property is shown to be protected by a pseudo-time-reversal symmetry that is pseudo-antiunitary and squares to $-1$, with the associated bulk topological invariant also being a $\mathbb Z_2$ index. We construct three equivalent expressions for it, relating to the Pfaffian, the pseudo-time-reversal polarization, and most practically, the Wannier center flow, all adopted from the fermionic case, defined here with respect to the pseudo inner product. In the presence of an additional pseudo-unitary and pseudo-Hermitian inversion symmetry, a simpler expression is derived. We then study two toy models feasible on cold atom platforms to numerically confirm the bulk-boundary correspondence. The Krein-space approach developed in this work is a universal formalism to study all kinds of symmetry-protected topological bosonic Bogoliubov bands.
description: 19 pages, 10 figures
Comet 2P/Encke in apparition of 2017: II. Polarization and color
Creators: name: Kiselev, Nikolai
name: Rosenbush, Vera
name: Ivanova, Oleksandra
name: Kolokolova, Ludmilla
name: Petrov, Dmitry
name: Kleshchonok, Valeriy
name: Afanasiev, Viktor
name: Shubina, Olena
Publisher: name: arXiv
Year: 2021
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We present results of imaging polarimetry of comet 2P/Encke performed on January 23, 2017 at the heliocentric (1.052 au) and geocentric (1.336 au) distances and phase angle 46.8 deg, 46 days before perihelion. Observations were made through the medium-band SED500 (λ5019/246 Å) and broadband r-sdss (λ6200/1200 Å) filters with the multimode focal reducer SCORPIO-2 at the 6-m BTA telescope of the Special Astrophysical Observatory (Russia). Dust in comet 2P/Encke was mainly concentrated in the near-nucleus region of the coma: the maximum dust/gas ratios were 1.5 and 2.9 in the SED500 and the r-sdss filters near the nucleus but dropped sharply to ~0.2 and ~1 at the distance ~2500 km, respectively. Then these ratios began to increase at distances ~12000 km from the nucleus, the ratio was ~0.3 (SED500) and ~1.3 (r-sdds). There were significant variations of polarization over the coma, which correlated with the variations in the dust color and dust/gas ratio. Changes in polarization and color across the 2P/Encke coma indicate changes in physical properties of the dust particles with the distance from the nucleus. Our Sh-matrix computer simulations of light scattering by Gaussian particles allow us to suggest that the observed trends in color and polarization are mainly result from changing particle size.
description: 12 pages, 10 figures, tables 2
BoltzTraP. A code for calculating band-structure dependent quantities
Creators: name: Madsen, Georg K. H.
name: Singh, David J.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: A program for calculating the semi-classic transport coefficients is described. It is based on a smoothed Fourier interpolation of the bands. From this analytical representation we calculate the derivatives necessary for the transport distributions. The method is compared to earlier calculations, which in principle should be exact within Boltzmann theory, and a very convincing agreement is found.
Nucleation of frictional sliding by coalescence of microslip
Creators: name: Schär, Styfen
name: Albertini, Gabriele
name: Kammer, David S.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: The onset of frictional motion is mediated by the dynamic propagation of a rupture front, analogous to a shear crack. The rupture front nucleates quasi-statically in a localized region of the frictional interface and slowly increases in size. When it reaches a critical nucleation length it becomes unstable, propagates dynamically and eventually breaks the entire interface, leading to macroscopic sliding. The nucleation process is particularly important because it determines the stress level at which the frictional interface fails, and therefore, the macroscopic friction strength. However, the mechanisms governing nucleation of frictional rupture fronts are still not well understood. Specifically, our knowledge of the nucleation process along a heterogeneous interface remains incomplete. Here, we study the nucleation of localized slip patches on linear slip-weakening interfaces with deterministic and stochastic heterogeneous friction properties. Using numerical simulations, we analyze the process leading to a slip patch of critical size for systems with varying correlation lengths of the local friction strength. Our deterministic interface model reveals that the growth of the critical nucleation patch at interfaces with small correlation lengths is non smooth due to the coalescence of neighboring slip patches. Existing analytical solutions do not account for this effect, which leads to an overestimation of global interface strength. Conversely, when the correlation length is large, the growth of the slip patch is continuous and our simulations match the analytical solution. Furthermore, nucleation by coalescence is also observed on stochastic interfaces with small correlation length...
Presolar grain dynamics: creating nucleosynthetic variations through a combination of drag and viscous evolution
Creators: name: Hutchison, Mark A.
name: Bodénan, Jean-David
name: Mayer, Lucio
name: Schönbächler, Maria
Publisher: name: arXiv
Year: 2022
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Meteoritic studies of solar system objects show evidence of nucleosynthetic heterogeneities that are inherited from small presolar grains (< 10 $μ$m) formed in stellar environments external to our own. The initial distribution and subsequent evolution of these grains are currently unconstrained. Using 3D, gas-dust simulations, we find that isotopic variations on the order of those observed in the solar system can be generated and maintained by drag and viscosity. Small grains are dragged radially outwards without size/density sorting by viscous expansion and backreaction, enriching the outer disc with presolar grains. Meanwhile large aggregates composed primarily of silicates drift radially inwards due to drag, further enriching the relative portion of presolar grains in the outer disc and diluting the inner disc. The late accumulation of enriched aggregates outside Jupiter could explain some of the isotopic variations observed in solar system bodies, such as the enrichment of supernovae derived material in carbonaceous chondrites. We also see evidence for isotopic variations in the inner disc that may hold implications for enstatite and ordinary chondrites that formed closer to the Sun. Initial heterogeneities in the presolar grain distribution that are not continuously reinforced are dispersed by diffusion, radial surface flows, and/or planetary interactions over the entire lifetime of the disc. For younger, more massive discs we expect turbulent diffusion to be even more homogenising, suggesting that dust evolution played a more central role in forming the isotopic anomalies in the solar system than originally thought.
description: 21 pages, 7 figures, accepted for publication in MNRAS
A model-independent constraint on the Hubble constant with gravitational waves from the Einstein Telescope
Creators: name: Zhang, Sixuan
name: Cao, Shuo
name: Zhang, Jia
name: Liu, Tonghua
name: Liu, Yuting
name: Geng, Shuaibo
name: Lian, Yujie
Publisher: name: arXiv
Year: 2020
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: In this paper, we investigate the expected constraints on the Hubble constant from the gravitational-wave standard sirens, in a cosmological-model-independent way. In the framework of the well-known Hubble law, the GW signal from each detected binary merger in the local universe ($z<0.10$) provides a measurement of luminosity distance $D_L$ and thus the Hubble constant $H_0$. Focusing on the simulated data of gravitational waves from the third-generation gravitational wave detector (the Einstein Telescope, ET), combined with the redshifts determined from electromagnetic counter parts and host galaxies, one can expect the Hubble constant to be constrained at the precision of $\sim 10^{-2}$ with 20 well-observed binary neutron star (BNS) mergers. Additional standard-siren measurements from other types of future gravitational-wave sources (NS-BH and BBH) will provide more precision constraints of this important cosmological parameter. Therefore, we obtain that future measurements of the luminosity distances of gravitational waves sources will be much more competitive than the current analysis, which makes it expectable more vigorous and convincing constraints on the Hubble constant in a cosmological-model-independent way.
description: 14 pages, 3 figures, accepted for publication in IJMPD
Probing Noncommutativity with Inflationary Gravitational Waves
Creators: name: Cai, Yi-Fu
name: Piao, Yun-Song
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Astrophysics (astro-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this paper we study the behaviour of gravitational wave background (GWB) generated during inflation in the environment of the noncommutative field approach. From this approach we derive out one additive term, and then we find that the dispersion relation of the gravitational wave would be modified and the primordial gravitational wave would obtain an effective mass. Therefore it breaks lorentz symmetry in local. Moreover, this additive term would a little raise up the energy spectrum of GWB in low frequency and then greatly suppress the spectrum at even lower energy scale of which the wave length may be near the current horizon. Therefore, a sharp peak is formed on the energy spectrum in the range of low frequencies. This peak should be a key criterion to detect the possible existence of noncommutativity of space-time in the background of our universe and a critical test for breaking lorentz symmetry in local field theory. Adding all possible effects on the evolution of GWB, we give some new information of the tensor power spectrum and its energy spectrum which may be probed in the future cosmological observations.
description: 10 pages, 4 figures, improved version
Washington, D.C.'s Streetcar Suburbs: A Comparative Analysis of Brookland and Brightwood, 1870-1900
Creators: name: Prince, Thomas Eugene
Publisher: name: Digital Repository at the University of Maryland
Year: 1979
Subjects: Brightwood (Washington, D.C.)
Brookland (Washington, D.C.)
Cable cars (Streetcars)
Suburbs

description: The evolution of public transportation systems in the
large American cities of the late nineteenth century culminated
in the innovation of the streetcar. Such transportation
changes affected urban structure and by the last
quarter of the century had produced a distinctive residential
area, the streetcar suburb. Washington, D.C. had a number
of such suburbs, some the result of subdivision development
associated with the extension of streetcar lines to link
existing village suburbs to the downtown core, others the
product of concurrent residential subdivision and streetcar
development. Such suburbs were predominantly middle-class,
white, residential areas.
An examination of two Washington, D.C. suburbs:
Brightwood and Brookland, indicated distinct physical,
social, economic, and demographic structures in these
village suburbs in the early 1880's. After the subsequent
introduction of streetcar links to downtown Washington--an
employment core characterized by much white-collar
government employment--the two suburbs became increasingly
similar in terms of the chosen measurements. By the end of
the century, there was little in their structures to indicate
the very different paths they had taken to the same end.
Foliations invariant under Lie group transverse actions
Creators: name: Behague, Alexandre
name: Scardua, Bruno
Publisher: name: arXiv
Year: 2006
Subjects: subject: Geometric Topology (math.GT)
subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 57R30, 22E15, 22E60

description: In this paper we study (smooth and holomorphic) foliations which are invariant under transverse actions of Lie groups.
Η Ψυχολογία της Απελευθέρωσης στη Λατινική Αμερική
Creators: name: Μυλωνάκη, Καλλιόπη Θεόδωρου
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: Απελευθέρωση
Κοινωνική ψυχολογία
Κριτική ψυχολογία
Liberation
Social Psychology
Critical Psychology

description: Η ψυχολογία της απελευθέρωσης προκύπτει από την κριτική των θέσεων της ψυχολογίας μέσα από μια αναθεωρημένη ερμηνεία του μαρξισμού, της ιστορικής διαλεκτικής και από τη βάση των ιδεών της θεολογίας της απελευθέρωσης, ιδωμένες μέσα από το πρίσμα του ιστορικού πλαισίου της Λατινικής Αμερικής. Οι πιο βασικές της συνιστώσες είναι η επιδίωξη της δικαιοσύνης, της ισότητας και της αξιοπρέπειας- η απελευθέρωση- για τους καταπιεσμένους και περιθωριοποιημένους λαούς σε όλο τον κόσμο. Η απελευθέρωση προκύπτει μέσα από τη συνειδητοποίηση, μια διαδικασία την οποία οι άνθρωποι αλλάζουν προς την κατεύθυνση της ανάπτυξης μιας κριτική συνείδησης που ανοίγει νέες δυνατότητες για δράση και κοινωνικές αλλαγές. Οι ψυχολόγοι μπορούν να συμβάλλουν σε αυτή τη διαδικασία μέσα από τη δουλειά τους, αφού αναλάβουν την ηθική και πολιτική δέσμευση να το κάνουν, κάτι που απαιτεί τη ρήξη με τις θεωρητικές και πρακτικές καταβολές του κυρίαρχου παραδείγματος στην ψυχολογία και την αναθεώρησή τους.
description: The psychology of liberation results from the criticism of the basic assumptions of psychology through a revised interpretation of Marxism, historical dialectic and on the base of ideas of theology of liberation, seen through the prism of historical frame of Latin America. It's most basic components are the objective of justice, equality and dignity - liberation- for the oppressed and marginalized populations all around the world. Liberation occurs through awareness, a process through which the people change to the direction of growing a critical conscience that opens new possibilities for action and social changes. The psychologists can contribute to this process through their work, by undertaking the moral and political engagement to do so, and that requires the rupture with the theoretical and practical roots of the hegemonic paradigm in the psychology and its revision.
Promoting autonomous learners in technology education
Creators: name: Rietchel, Craig John
Publisher: name: University of British Columbia
Year: 2009

description: This study incorporates action research methodology and focuses on the promotion of autonomous learners in technology education. A self examination of one teacher's attempt to involve students in the direction of their education is conducted to encourage change in student performance. This research enhances praxis knowledge, facilitating changes in pedagogical approaches through an evolving theoretical/practical base. The study incorporates views of researchers and philosophers, and is closely aligned with research into teachers' promotion of autonomy in institutional settings. Current literature focuses on classroom strategies, problems solving techniques, teacher influence and autonomous learner characteristics. Institutional constraints, teacher attitudes, and learners pre-existing concepts and beliefs are dealt with as limitations. This research captures the pedagogical practices of a teacher/researcher's work with grade nine and ten students in the context of technology education. Methods of data collection and analysis employ standards of observation, reflection and collaboration through journal writing over a fourteen month period. Collaboration with a critical colleague and an academic researcher maintain validity in recognizing changes in teacher action and student performance over time. Through the duration of the study, students are perceived to develop self confidence, self directed and self reliant attitudes, indicative of learner autonomy. Students demonstrate greater enthusiasm, more drive and determination, and reveal growth in their ability to welcome risks and manage tasks. The data analysis suggests three fundamental themes for developing personal skills in students and draws on a problem solving model as a practical vehicle for developing learner autonomy. Firstly, students are encouraged to gradually take charge of their learning, developing personal responsibility. Secondly, independent thinking is promoted, providing opportunities for students to learn, make decisions, and identify and solve problems on their own. Thirdly, students are encouraged to make personal connections with their work, stimulating intrinsic motivation. Finally, a problem solving model is incorporated as a vehicle for addressing these three elements of personal development. Educational priorities focus on educating students first as life long learners and providing subject material second as vehicles for addressing personal development. As research specific to technology education is limited, this study attempts to stimulate further research into pedagogical practice, classroom techniques and teacher preparation for addressing learner autonomy in the classroom. Continuous examination will inform academics, researchers and teachers, establishing the development of learner autonomy as a viable pedagogy for improving student performance.
WMAP2006: Cosmological Parameters and Large-scale Structure of the Universe
Creators: name: Apunevych, S.
name: Venhlovska, B.
name: Kulinich, Yu.
name: Novosyadlyj, B.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The parameters of cosmological model with cold dark matter and cosmological constant (Lambda CDM) have been determined on a basis of three-year cosmic microwave background observations by space mission WMAP, as well as the data on the large-scale structure of the Universe. The data cover scales from 1 up to 10000 Mpc. The best-fit values of LambdaCDM model parameters were found by minimization of chi^2 using the Levenberg-Markquardt approach (Omega_Lambda=0.736+-0.065, Omega_m=0.238+-0.080, Omega_b=0.05+-0.011, h=0.68+- 0.09, sigma_8=0.73+-0.08 and n_s=0.96+-0.015). It is shown that the LambdaCDM model with these values of the parameters agrees well with the angular power spectrum of cosmic microwave background and with power spectra of the density perturbations, estimated from spatial distributions of galaxies, rich galaxy clusters and from statistics of Ly_alpha absorption lines in spectra of distant quasars as well. The accordance of modeled characteristics of the large-scale structure with observable ones was analyzed, and possible reasons of significant discrepancies between some of them were considered.
description: 12 pages, 6 figures, translation from Ukrainian
Pulsars with NenuFAR: backend and pipelines
Creators: name: Bondonneau, L.
name: Grießmeier, J. -M.
name: Theureau, G.
name: Cognard, I.
name: Brionne, M.
name: Kondratiev, V.
name: Bilous, A.
name: McKee, J. W.
name: Zarka, P.
name: Viou, C.
name: Guillemot, L.
name: Chen, S.
name: Main, R.
name: Pilia, M.
name: Possenti, A.
name: Serylak, M.
name: Shaifullah, G.
name: Tiburzi, C.
name: Verbiest, J. P. W.
name: Wu, Z.
name: Wucknitz, O.
name: Yerin, S.
name: Briand, C.
name: Cecconi, B.
name: Corbel, S.
name: Dallier, R.
name: Loh, A.
name: Martin, L.
name: Girard, J. N.
name: Tasse, C.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: NenuFAR (New extension in Nançay upgrading LoFAR) is a new radio telescope developed and built on the site of the Nançay Radio Observatory. It is designed to observe the largely unexplored frequency window from 10 to 85\,MHz, offering a high sensitivity across its full bandwidth. NenuFAR has started its "early science" operation in July 2019, with 58\% of its final collecting area being available. Pulsars are one of the major topics for the scientific exploitation of this frequency range and represent an important challenge in terms of instrumentation. Designing instrumentation at these frequencies is complicated by the need to compensate for the effects of both the interstellar medium and the ionosphere on the observed signal. Our real-time pipeline LUPPI (Low frequency Ultimate Pulsar Processing Instrumentation) is able to cope with a high data rate and to provide real-time coherent de-dispersion down to the lowest frequencies reached by NenuFAR (10\,MHz). The full backend functionality is described, as well as the main pulsar observing modes (folded, single-pulse, waveform, and dynamic spectrum). This instrumentation allowed us to detect 172 pulsars in our first targeted search below 85\,MHz, including 10 millisecond pulsars (6 of which detected for the first time below 100 MHz). We also present some of the "early science" results of NenuFAR on pulsars: a high frequency resolution mapping of PSR B1919$+$21's emission profile and a detailed observation of single-pulse sub-structures from PSR~B0809$+$74 down to 16\,MHz, the high rate of giant-pulse emission from the Crab pulsar detected at 68.7\,MHz (43 events/min), and the illustration of the very good timing performance of the instrumentation, allowing us to study dispersion measure variations in great detail.
description: 13 pages, 14 figures, submitted to A&A
The Hard X-ray Spectral Slope as an Accretion-Rate Indicator in Radio-Quiet Active Galactic Nuclei
Creators: name: Shemmer, Ohad
name: Brandt, W. N.
name: Netzer, Hagai
name: Maiolino, Roberto
name: Kaspi, Shai
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present new XMM-Newton observations of two luminous and high accretion-rate radio-quiet active galactic nuclei (AGNs) at z~2. Together with archival X-ray and rest-frame optical spectra of three sources with similar properties as well as 25 moderate-luminosity radio-quiet AGNs at z<0.5, we investigate, for the first time, the dependence of the hard (>~2 keV) X-ray power-law photon index on the broad H_beta emission-line width and on the accretion rate across ~3 orders of magnitude in AGN luminosity. Provided the accretion rates of the five luminous sources can be estimated by extrapolating the well-known broad-line region size-luminosity relation to high luminosities, we find that the photon indices of these sources, while consistent with those expected from their accretion rates, are significantly higher than expected from the widths of their H_beta lines. We argue that, within the limits of our sample, the hard-X-ray photon index depends primarily on the accretion rate.
description: 4 pages (emulateapj), 2 figures. Accepted for publication in ApJ Letters
Núcleo de dados de psquisa: um modelo de governança para a iniciativa de rede brasileira de repositórios institucionais de dados de pesquisa
Creators: name: Felicíssimo, Carolina
Publisher: name: Zenodo
Year: 2024

description: Apresentação realizada na sessão Pecha Kucha I, da 15ª Conferência Lusófona de Ciência Aberta, na Escola Superior de Enfermagem do Porto (ESEP), de 01 a 04 de outubro de 2024.