cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
title: Hydrodynamic-sea ice couplings in the Barents Sea and their consequences for marine productivity
Creators: name: Schrum, Corinna
name: Daewel, Ute
name: Castaño-Primo, Rocío
Publisher: name: ASC 2013 - Theme session L
Year: 2024
Subjects: Ecosystem observation, processes and dynamics

description: No abstracts are to be cited without prior reference to the author. During the past decades the Barents Sea experienced pronounced changes in hydrodynamic-, biogeochemical and higher trophic level conditions. The sea ice cover showed a long-term decreasing trend, which seems to have slightly stabilized during the recent years (Karaskov et al., 2013). Barents Sea temperature is characterized by significant multidecadal variability, which correlates to the Atlantic Multidecadal Oscillation AMO (e.g. Levitus, et al., 2009) and covariations with cyclone activity have been identified in earlier studies (e.g. Sorteberg and Kvingedal, 2006). These long-term variations in oceanographic conditions are accompanied by pronounced variations in the ecosystem with a.o. an increase in fish abundance and an expansion of key stocks northwards (e.g. Stiansen et al., 2009). Based on model simulations of contrasting years, it has earlier been suggested that sea ice retreat will result in increasing primary production in the Barents Sea (e.g. Wassmann et al., 2006). We investigate long-term variations in bottom up controls on the lower trophic level production in the Barents Sea by employing a regional physical-biological model for a multi-decadal simulation. We will illustrate the impact of climatic forcing on lower trophic level production in the Barents Sea and discuss the variations in dominant climatic drivers over the decades.
Ecological equilibrium for restrained branching random walks
Creators: name: Bertacchi, Daniela
name: Posta, Gustavo
name: Zucca, Fabio
Publisher: name: arXiv
Year: 2006
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 60K35 (Primary)

description: We study a generalized branching random walk where particles breed at a rate which depends on the number of neighboring particles. Under general assumptions on the breeding rates we prove the existence of a phase where the population survives without exploding. We construct a nontrivial invariant measure for this case.
description: Published in at http://dx.doi.org/10.1214/105051607000000203 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Mining big datasets to create and validate machine learning models
Creators: name: Ekins, Sean
name: Clark, Alex
Publisher: name: F1000Research
Year: 2015

description: We have recently described a reference implementation of Bayesian model building using ECFP and FCFP-type fingerprints. We have now undertaken a large scale validation study in order to ensure that the technique generalizes to a broad variety of drug discovery and ADME/Tox datasets. To achieve this we have used the ChEMBL (version 20) and ToxCast databases, each of which consists of compounds and measurements with an assay and activity measurement. In order to test these datasets with a two-state Bayesian classification, we developed an automated algorithm for detecting a suitable threshold for active/inactive designation, which we applied to all data. With these datasets we were able to establish that our Bayesian model implementation is effective for the large majority of cases, and were able to quantify the impact of fingerprint folding on the ROC cross validation metrics. We were also able to study the impact that the choice of training/testing set partitioning has on the resulting recall rates. The datasets have been made publicly available to be downloaded, along with the corresponding model data files, which can be used in conjunction with the CDK toolkit and several mobile apps. The ability to score molecules across thousands of relevant datasets across organisms also may help to access desirable and undesirable off-target effects.
Properties of tabulated bidirectional reflectance distribution functions
Creators: name: DeYoung, Joel M.
Publisher: name: University of British Columbia
Year: 2009

description: One way to overcome the limitations imposed by analytical models of reflection is to use discretely sampled reflectance data directly. Through either empirical measurement or simulation, a bidirectional reflectance distribution function (BRDF) is acquired that is represented by a table of numbers. The generality of these measured BRDFs is useful for generating realistic images, but the inevitable inaccuracy associated with the data gathering process can lead to a BRDF that is more general than it needs to be, or that lacks certain physical properties. This thesis proposes measures for several properties of BRDFs: reciprocity, energy conservation, isotropy, and separability. Techniques to transform tabulated BRDFs to match one or more of these properties are also described. These transformations allow compression of the BRDF data, elimination of noise, improved computation time in some rendering tasks, and improved compliance with physical laws.
Bounded Rank-one Perturbations in Sampling Theory
Creators: name: Silva, Luis O.
name: Toloza, Julio H.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: Spectral Theory (math.SP)
subject: FOS: Mathematics
subject: 41A05, 46E22, 47A55, 47B25, 47N99, 94A20

description: Sampling theory concerns the problem of reconstruction of functions from the knowledge of their values at some discrete set of points. In this paper we derive an orthogonal sampling theory and associated Lagrange interpolation formulae from a family of bounded rank-one perturbations of a self-adjoint operator that has only discrete spectrum of multiplicity one.
description: 13 pages; v2: minor corrections on grammar and spelling, some of the statements are now more accurate
The problem determination of Functional Dependencies between attributes Relation Scheme in the Relational Data Model. El problema de determinar Dependencias Funcionales entre atributos en los esquemas en el Modelo Relacional
Creators: name: Vega-Paez, Ignacio
name: Pulido, Georgina G.
name: Ortega, Jose Angel
Publisher: name: arXiv
Year: 2007
Subjects: subject: Databases (cs.DB)
subject: Data Structures and Algorithms (cs.DS)
subject: FOS: Computer and information sciences

description: An alternative definition of the concept is given of functional dependence among the attributes of the relational schema in the Relational Model, this definition is obtained in terms of the set theory. For that which a theorem is demonstrated that establishes equivalence and on the basis theorem an algorithm is built for the search of the functional dependences among the attributes. The algorithm is illustrated by a concrete example
$β$ Cephei Pulsations in the High-mass Eclipsing System CW Cephei
Creators: name: Lee, Jae Woo
name: Hong, Kyeongsoo
Publisher: name: arXiv
Year: 2020
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: CW Cep is an early B-type eclipsing binary with mass measurement precisions better than 1 \%. We report the discovery of pulsation signatures in the TESS time-series data of the system observed during Sectors 17 and 18. Our binary modeling indicates that the target star is a partially-eclipsing detached system with masses of 12.95 $M_\odot$ and 11.88 $M_\odot$ and radii of 5.52 $R_\odot$ and 5.09 $R_\odot$ in an eccentric orbit of $e$ = 0.0305. The distance to the eclipsing system, 928 $\pm$ 36 pc, is much more precise than the Gaia distance of 962 $\pm$ 453 pc. Applying multifrequency analyses to the residual light curve in the outside-eclipse part, we detected 13 significant signals in two frequency regions. Six frequencies below 1 day$^{-1}$ appeared to be mostly orbital harmonic and combination terms, or sidelobes due to insufficient removal of the binary effects. In contrast, seven frequencies clustered around 2.73 day$^{-1}$ and 5.34 day$^{-1}$ could be considered $β$ Cep-type pulsations. Our results represent the second discovery of $β$ Cep pulsations present in double-lined eclipsing binaries with precise masses and, hence, CW Cep serves as an important test-bed for the asteroseismic modeling of high-mass stars.
description: 15 pages, including 4 figures and 3 tables
title: Variability of water properties, currents and fluxes in Nares Strait, connecting the Arctic to the Atlantic Ocean
Creators: name: Rabe, Berit
name: Münchow, Andreas
name: Johnson, Helen Louise
name: Melling, Humfrey
Publisher: name: ASC 2013 - Theme session L
Year: 2024
Subjects: Ecosystem observation, processes and dynamics

description: No abstracts are to be cited without prior reference to the author. Enhanced delivery of fresh cold waters from the Arctic along Labrador contributes to vertical stratification as far south as the Mid-Atlantic Bight where interannual ecosystem variability appears to correlate with upstream conditions in the Canadian Arctic Archipelago (CAA). Nares Strait between Greenland and the CAA provides a seawater pathway between the Arctic and Atlantic Oceans. A mooring array across the strait has provided information on water properties, currents and fluxes from 2003 to 2012. These are strongly influenced by the sea ice state in the strait, which varies from mobile in summer to land-fast in winter caused by ice bridge formation to the south. The geostrophic freshwater flux shows fluctuations linked to change in weather and season (enhanced during mobile ice season). Change in the annual ice cover cycle, such as recent failures of ice bridge formation, greatly extends the mobile ice season. A future increase of failures could allow a higher freshwater flux to the south, deeper mixing of brackish surface waters, and a stronger dependence of flow on local atmospheric forcing. Our developing understanding of fluxes through Nares Strait will guide future improvement in the representation of the global hydrologic cycle in climate models.
On the divergences of inflationary superhorizon perturbations
Creators: name: Enqvist, K.
name: Nurmi, S.
name: Podolsky, D.
name: Rigopoulos, G. I.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We discuss the infrared divergences that appear to plague cosmological perturbation theory. We show that within the stochastic framework they are regulated by eternal inflation so that the theory predicts finite fluctuations. Using the $ΔN$ formalism to one loop, we demonstrate that the infrared modes can be absorbed into additive constants and the coefficients of the diagrammatic expansion for the connected parts of two and three-point functions of the curvature perturbation. As a result, the use of any infrared cutoff below the scale of eternal inflation is permitted, provided that the background fields are appropriately redefined. The natural choice for the infrared cutoff would of course be the present horizon; other choices manifest themselves in the running of the correlators. We also demonstrate that it is possible to define observables that are renormalization group invariant. As an example, we derive a non-perturbative, infrared finite and renormalization point independent relation between the two-point correlators of the curvature perturbation for the case of the free single field.
description: 12 pages
EVOLUTION OF ICONOGRAPHY IN ASSAM ACROSS THE EPOCHS: A COMPREHENSIVE STUDY OF HISTORICAL AND CULTURAL TRANSFORMATIONS
Creators: name: Dr. NILAM NANDINI SARMAH
Publisher: name: Zenodo
Year: 2024
Subjects: Iconography, Assam, Brahmanical Deities, Cultural Transformations, Socio-Religious History.

description: Abstract

This study explores the dynamic evolution of iconography in Assam, delving into the intricate interplay of historical and cultural transformations across epochs. The socio-religious history of the region unfolds as a rich tapestry, woven with the threads of diverse faiths and beliefs. Key themes include settlements, ethnic migrations, socio-economic and political shifts, environmental changes, natural calamities, and the infusion of new ideologies. Cult images and icons of deities, serving as tangible reflections of spiritual metamorphosis, form a central focus. Monument building emerges as a visual narrative, encapsulating the adaptation of new ideas and expressions within the religious landscape. The study specifically scrutinizes the iconography of Brahmanical deities, providing a regional perspective. A succinct overview of the landscape, political history, and monumental landmarks sets the stage for a nuanced exploration.
Andronov-Hopf Bifurcations in Planar, Piecewise-Smooth, Continuous Flows
Creators: name: Simpson, D. J. W.
name: Meiss, J. D.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: An equilibrium of a planar, piecewise-$C^1$, continuous system of differential equations that crosses a curve of discontinuity of the Jacobian of its vector field can undergo a number of discontinuous or border-crossing bifurcations. Here we prove that if the eigenvalues of the Jacobian limit to $λ_L \pm {\rm i} ω_L$ on one side of the discontinuity and $-λ_R \pm {\rm i} ω_R$ on the other, with $λ_L, λ_R >0$, and the quantity $ Λ= λ_L / ω_L -λ_R / ω_R $ is nonzero, then a periodic orbit is created or destroyed as the equilibrium crosses the discontinuity. This bifurcation is analogous to the classical Andronov-Hopf bifurcation, and is supercritical if $Λ< 0$ and subcritical if $Λ>0$.
description: laTex, 18 pages, 8 figures
The quantum phase transitions of dimer chain driven by an imaginary ac field
Creators: name: Liu, C. S.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: A topologically equivalent tight binding model is proposed to study the quantum phase transitions of dimer chain driven by an imaginary ac field. I demonstrate how the partner Hamiltonian is constructed by a similarity transformation to fulfil the $\mathcal{PT}$ symmetry. The $\mathcal{PT}$ symmetry of the partner model allows us to study the topological properties of the original non-Hermitian model as the Bloch bands of the Hermitian system. The quantum phase transitions are discussed in different frequency regime. The approach has the potential applications to investigate the topological states of matter driven by the complex external parameters.
description: 7 pages, 3 figures
title: Seasonal Variability of the East Greenland Coastal Current
Creators: name: Marshall, Abigail
name: Bacon, Sheldon
name: Holliday, N. Penny
name: Askenov, Yevgeny
name: Dye, Stephen
Publisher: name: ASC 2013 - Theme session L
Year: 2024
Subjects: Ecosystem observation, processes and dynamics

description: No abstracts are to be cited without prior reference to the author. The East Greenland Coastal Current (EGCC) is a cold (θ < 4 °C), freshwater (28 < S < 34) wedge which resides close to the East Greenland coast, extending up to 40 km from the shore. It is a major conduit of freshwater from the Arctic Ocean. However, the seasonal cycle, transport and drivers of the EGCC are unknown due to the lack of wintertime measurements. Here we describe the EGCC seasonal cycle from moorings, transport values using the global model, NEMO, and postulate what could be driving the EGCC. The moorings recorded salinity, temperature and velocities from 2000-2004 showing the EGCC exists throughout the year, strengthening in the winter. Annually, freshening occurred during the spring ice melt, as expected. The model, corroborated by the moorings, calculated freshwater transport (referenced to 35.0) at 84 mSv, peaking in winter (106 mSv) and reducing in summer (59 mSv). Further calculations showed that the cross-shelf density is more important in driving the EGCC than the wind through sea surface height variability. However, the strong equatorward winds over the winter are influential as they force the wedge via Ekman transport towards the coast causing steeper isopycnals thereby increasing the winter velocities and transport.
Continuous-time quantum walks on ultrametric spaces
Creators: name: Konno, Norio
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We introduce a continuous-time quantum walk on an ultrametric space corresponding to the set of p-adic integers and compute its time-averaged probability distribution. It is shown that localization occurs for any location of the ultrametric space for the walk. This result presents a striking contrast to the classical random walk case. Moreover we clarify a difference between the ultrametric space and other graphs, such as cycle graph, line, hypercube and complete graph, for the localization of the quantum case. Our quantum walk may be useful for a quantum search algorithm on a tree-like hierarchical structure.
description: 13 pages, small corrections, Journal-ref added
Enhancement of spin-orbit coupling in Dirac semimetal Cd$_{3}$As$_{2}$ films by Sb-doping
Creators: name: Nakazawa, Yusuke
name: Uchida, Masaki
name: Nishihaya, Shinichi
name: Ohno, Mizuki
name: Sato, Shin
name: Kawasaki, Masashi
Publisher: name: arXiv
Year: 2021
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We present a study on magnetotransport in films of the topological Dirac semimetal Cd$_{3}$As$_{2}$ doped with Sb grown by molecular beam epitaxy. In our weak antilocalization analysis, we find a significant enhancement of the spin-orbit scattering rate, indicating that Sb doping leads to a strong increase of the pristine band-inversion energy. We discuss possible origins of this large enhancement by comparing Sb-doped Cd$_{3}$As$_{2}$ with other compound semiconductors. Sb-doped Cd$_{3}$As$_{2}$ will be a suitable system for further investigations and functionalization of topological Dirac semimetals.
description: 16 pages, 4 figures
title: The retroflection of the Faroe Current into the Faroe‐Shetland Channel
Creators: name: Larsen, Karin Margretha H.
name: Hansen, Bogi
name: Hátún, Hjálmar
Publisher: name: ASC 2013 - Theme session L
Year: 2024
Subjects: Ecosystem observation, processes and dynamics

description: No abstracts are to be cited without prior reference to the author. The Faroe Current (FC) flows eastward north of the Faroes, but when it reaches the northeastern corner of the Faroe Plateau a part of it is retroflected back into the Faroe Shetland Channel (FSC). Here Mean Sea Level Anomaly (MSLA) data and current mooring data are used to explore the variability of the retroflected FC. An EOF analysis of the MSLA indicates that there is a link between the MSLA over the central Nordic Seas and the strength of the FC and its retroflection. The first PC is compared to velocity data in the FC and the FSC. The comparison indicates that the variability of the MSLA is reflected in the velocities in the FC and along the slope on the Faroese side of the FSC, but not in the central part of the channel. The first PC has a strong seasonal signal resulting in the strongest velocities in January. Additionally, the first PC has an inter‐annual variability that can be interpreted to cause the apparent variable strength of the reflected FC and how far it progresses into the FSC.
title: OceanScope – Partnering with industry for the sustained and systematic observation of the oceans.
Creators: name: Rossby, Thomas
name: Flagg, Charles
name: Schrum, Corinna
Publisher: name: ASC 2013 - Theme session L
Year: 2024
Subjects: Ecosystem observation, processes and dynamics

description: No abstracts are to be cited without prior reference to the author. A recent report ‘OceanScope’ (see link to report below) outlines in detail a proposed partnership with the global shipping industry to create a framework for expanded observation of the global water column. The partnership would also establish a framework to stimulate the development of novel sensors and instruments optimized for use on merchant marine vessels. To motivate and achieve the above requires scalability of operations that leads to improved coverage of the ocean on the one hand, and economic incentives on the other for investing in such initiatives. The initial phase of OceanScope would focus on the North Atlantic. Recent findings from vessels operating acoustic Doppler current profilers (ADCP) will serve to illustrate the power of repeat sampling.
Διατύπωση μεθοδολογίας για την επιλογή διατομής της οδού με τη βοήθεια συγκριτικής θεώρησης διεθνών πρακτικών για τον προσδιορισμό της χωρητικότητας των οδών και των επιπέδων εξυπηρέτησης της κυκλοφορ:
Creators: name: Ελευθεριάδου, Μαρία Ιωάννη
Publisher: name: Aristotle University of Thessaloniki
Year: 2011
Subjects: Κυκλοφοριακή ικανότητα
Διατομή
Ομοε
Capacity
Road cross section
Highway capacity manual

description: Η παρούσα διπλωματική φέρει τον τίτλο “Διατύπωση μεθοδολογίας για την επιλογή διατομής της οδού με τη βοήθεια συγκριτικής θεώρησης διεθνών πρακτικών για τον προσδιορισμό της χωρητικότητας των οδών και των επιπέδων εξυπηρέτησης της κυκλοφορίας”.Η μελέτη έχει ως αντικείμενο την συγκριτική θεώρηση της μεθοδολογίας του υφιστάμενου παραρτήματος ΙΙ των Οδηγιών Μελετών Οδικών Έργων (ΟΜΟΕ-Δ) με πρότυπο το κείμενο του Highway Capacity Manual 2000 και το σχολιασμό των αριθμητικών του στοιχείων με δεδομένα από μετρήσεις στο πεδίο.Η μεθοδολογία που ακολουθήθηκε αρχικά ,ήταν η μετάφραση αποσπασμάτων του HCM και η διατύπωση πρότασης επαναδιατύπωσης του παραρτήματος ΙΙ των ΟΜΟΕ-Δ. Ακολουθεί,διεξοδική σύγκριση των δύο εγχειριδίων και στη συνέχεια,χρησιμοποιώντας νέα κυκλοφοριακά δεδομένα από οδούς με τα υπό μελέτη χαρακτηριστικά επιχειρείται η επικαιροποίηση του παραρτήματος.Στόχοι της εργασίας είναι η κατανόηση της μεθοδολογίας του HCM ,η αποσαφήνιση και ο σχολιασμός της μεθοδολογίας του παραρτήματος και η διατύπωση υποδείξεων για την ορθή του χρήση μέσω παραδειγμάτων. Τέλος,διατυπώνονται σχόλια με σκοπό την μελλοντική συνολική του αναθεώρηση και επικαιροποίηση μέσω των νέων μετρήσεων πεδίου.
description: This diploma thesis is titled “Determination of a methodology for the assessment of the road cross section through the comparison among international practices in terms of capacity analysis and levels of service”.The thesis deals with the restructuring of the present methodology ,as described in the Greek regulations, following the instructions set by the Highway capacity manual and its update using current field measurements.The methodology that was followed included the translation of certain parts of the Highway Capacity Manual in order to restructure the Greek manual,the detailed comparison between the two manuals and finally the processing of updated traffic data.The thesis aims to present the methodology given in HCM,to clarify the methodology presented in the Greek manual,to provide instructions for its proper use with examples,to end up in comments leading to its future remake with the use of updated traffic data.
Panchromatic Properties of 99,000 Galaxies Detected by SDSS, and (some by) ROSAT, GALEX, 2MASS, IRAS, GB6, FIRST, NVSS and WENSS Surveys
Creators: name: Obric, M.
name: Ivezic, Z.
name: Best, P. N.
name: Lupton, R. H.
name: Tremonti, C.
name: Brinchmann, J.
name: Agueros, M. A.
name: Knapp, G. R.
name: Gunn, J. E.
name: Rockosi, C. M.
name: Schlegel, D.
name: Finkbeiner, D.
name: Gacesa, M.
name: Smolcic, V.
name: Anderson, S. F.
name: Voges, W.
name: Juric, M.
name: Siverd, R. J.
name: Steinhardt, W.
name: Jagoda, A. S.
name: Blanton, M. R.
name: Schneider, D. P.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We discuss the panchromatic properties of 99,088 galaxies selected from the SDSS Data Release 1 spectroscopic sample (a flux-limited sample for 1360 deg^2). These galaxies are positionally matched to sources detected by ROSAT, GALEX, 2MASS, IRAS, GB6, FIRST, NVSS and WENSS. We find strong correlations between the detection fraction at other wavelengths and optical properties such as flux, colors, and emission-line strengths. Using GALEX, SDSS, and 2MASS data, we construct the UV-IR broad-band spectral energy distributions for various types of galaxies, and find that they form a nearly one-parameter family. For example, based on SDSS u- and r-band data, supplemented with redshift, the K-band 2MASS magnitudes can be "predicted" with an rms scatter of only 0.2 mag. When a dust content estimate determined from SDSS data by Kauffmann et al. (2003) is also utilized, this scatter decreases to 0.1 mag. We demonstrate that this dust content is indeed higher for galaxies detected by IRAS and that it can be used to "predict" measured IRAS 60 micron flux density within a factor of two using only SDSS data. We also show that the position of a galaxy in the emission-line-based Baldwin-Phillips-Terlevich diagram is correlated with the optical light concentration index and u-r color determined from the SDSS broad-band imaging data, and discuss changes in the morphology of this diagram induced by requiring detections at other wavelengths. We study the IR-radio correlation and find evidence that its slope may be different for AGN and star-forming galaxies and related to the H_alpha/H_beta line strength ratio.
description: Accepted for publication in MNRAS; 25 pages, 32 color figures
Scrutinizing Exotic Cosmological Models Using ESSENCE Supernova Data Combined with Other Cosmological Probes
Creators: name: Davis, T. M.
name: Mortsell, E.
name: Sollerman, J.
name: Becker, A. C.
name: Blondin, S.
name: Challis, P.
name: Clocchiatti, A.
name: Filippenko, A. V.
name: Foley, R. J.
name: Garnavich, P. M.
name: Jha, S.
name: Krisciunas, K.
name: Kirshner, R. P.
name: Leibundgut, B.
name: Li, W.
name: Matheson, T.
name: Miknaitis, G.
name: Pignata, G.
name: Rest, A.
name: Riess, A. G.
name: Schmidt, B. P.
name: Smith, R. C.
name: Spyromilio, J.
name: Stubbs, C. W.
name: Suntzeff, N. B.
name: Tonry, J. L.
name: Wood-Vasey, W. M.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The first cosmological results from the ESSENCE supernova survey (Wood-Vasey et al. 2007) are extended to a wider range of cosmological models including dynamical dark energy and non-standard cosmological models. We fold in a greater number of external data sets such as the recent Higher-z release of high-redshift supernovae (Riess et al. 2007) as well as several complementary cosmological probes. Model comparison statistics such as the Bayesian and Akaike information criteria are applied to gauge the worth of models. These statistics favor models that give a good fit with fewer parameters. Based on this analysis, the preferred cosmological model is the flat cosmological constant model, where the expansion history of the universe can be adequately described with only one free parameter describing the energy content of the universe. Among the more exotic models that provide good fits to the data, we note a preference for models whose best-fit parameters reduce them to the cosmological constant model.
description: Accepted by ApJ. v2: Two figures added, minor typographical corrections. 10 pages, 9 figures
title: Can dense water formation act as a primer for the spring-bloom on Spitsbergenbanken?
Creators: name: Lien, Vidar S.
name: Ådlandsvik, Bjørn
Publisher: name: ASC 2013 - Theme session L
Year: 2024
Subjects: Ecosystem observation, processes and dynamics

description: No abstracts are to be cited without prior reference to the author. Our hypothesis, that dense water formation may act as a pre-conditioner for spring-blooms through stratification of the water column at the Spitsbergenbanken slope, finds some support in the current study. We cannot, however, draw any firm conclusions based on available data
title: Long-term changes in the temperature and salinity distribution patterns in the Gulf of Riga
Creators: name: Skudra, Maris
name: Lips, Urmas
Publisher: name: ASC 2013 - Theme session L
Year: 2024
Subjects: Ecosystem observation, processes and dynamics

description: No abstracts are to be cited without prior reference to the author. Global-scale circulations certainly leave the imprints on regional patterns in the regional coastal seas. The Gulf of Riga is situated at the eastern part of the Baltic Sea and by its latitudinal location represents a boreal environment.
Light fragment and neutron emission in high-energy proton induced spallation reactions
Creators: name: Cheng, Hui-Gan
name: Feng, Zhao-Qing
Publisher: name: arXiv
Year: 2020
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The dynamics of high-energy proton-induced spallation reactions on target nuclides of $^{136}$Xe, $^{59}$Ni, $^{56}$Fe, $^{208}$Pb, $^{184}$W, $^{181}$Ta, $^{197}$Au and $^{112}$Cd, are investigated with the quantum molecular dynamics transport model. The production mechanism of light nuclides and fission fragments is thoroughly analyzed. The statistical code GEMINI is employed in conjunction to the model for managing the decay of primary fragments. For the treatment of cluster emission during the preequilibrium stage, a surface coalescence model is implemented into the model. It is found that the available data of total cross sections are well reproduced with the combined approach for the spallation reactions on both the heavy and light targets, i.e., $^{56}$Fe and $^{208}$Pb, while it is underestimated in the intermediate-mass-fragment region for the medium-mass target $^{136}$Xe. The energetic clusters are mainly contributed from the preequilibrium recognition, in which the quantum tunneling is taken into account. On the other hand, a fairly well overall description of light cluster and neutron emission is obtained and detailed discrepancies with respect to the experimental results are discussed. Possible modifications on the description of spallation reactions are stressed and compared with both recent experimental and theoretical results in the literature.
description: 12 pages, 7 figures
Starting small companies focused on rare disease
Creators: name: Ekins, Sean
name: Wood, Jill
Publisher: name: F1000Research
Year: 2015

description: In the space of a few years, between us we have been formed two rare disease focused companies. In one case this resulted from meeting several parents of children with rare diseases. One company, Phoenix Nest (http://www.phoenixnestbiotech.com/) was co-Founded with a rare disease parent and is working on treatments for Sanfilippo syndrome a devastating neurodegenerative lysosomal storage disorder of childhood. In the space of 2 years we have built up collaborations with leading academics and industry and submitted multiple grant proposals. We were able to secure our first NIH NINDS STTR recently to fund development of an enzyme replacement therapy with our academic collaborator, and this sets the stage for our growth. All of our resources are spent on supporting research and development with minimal overhead as we leverage collaborative researchers and tools to ensure we reach our goal. The second company, Collaborations Pharmaceuticals Inc. (http://www.collaborationspharma.com/) was founded in an attempt to scale this strategy to address some of the other 7000 or so rare diseases as well as infectious diseases, many of which are neglected or rare. Lessons learned in this process are that anyone can start a company and it can be done cheaply. In order to start a rare disease company, parents, patients or advocates that have started their own foundation and know all the science and scientists are in the ideal position. As a scientist knowing that such parents exist was highly influential. Ideally having at least one scientist with whom you can submit grants and ultimately license what comes out of the work is important as well as having someone involved that can write grants and papers for the company. We would encourage other scientists to meet rare disease parents, patients or advocates and work with them to further the science on their diseases.
High Frequency VLBI Imaging of the Jet Base of M87
Creators: name: Ly, Chun
name: Walker, R. Craig
name: Junor, William
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: VLBA and Global VLBI observations of M87 at 43 GHz, some new and some previously published, are used to study the structural evolution of the jet with a spatial resolution of under 100 Schwarzschild radii. The images, taken between 1999 and 2004, have an angular resolution of 0.00043" x 0.00021". An edge-brightened jet structure and an indication of a large opening angle at the jet base are seen in all five epochs. In addition, a probable counter-jet is seen in the latter three epochs. A 22 GHz VLBA image also confirms many of the structures seen at the higher frequency, including the counter-jet. A comparison of the counter-jet flux density at 22 and 43 GHz reveals that it is not free-free absorbed at these frequencies. Attempts to obtain speeds from the proper motions of jet and counter-jet components indicate that these observations are undersampled. The closest pair of images gives apparent speeds of 0.25 to 0.40c for the jet and 0.17c for the counter-jet. These speeds should be treated as lower limits because of possible errors in associating components between epochs. If they are real, they indicate that the jet is oriented 30-45 degrees from the line-of-sight and that the component speeds along the jet are 0.3-0.5c. Using the jet orientation derived from proper motions, the spectral index of the the counter-jet, and a jet-to-counter-jet brightness ratio of 14.4, the inferred bulk flow is 0.6-0.7c, which, given the considerable uncertainties in how to measure the brightness ratio, is not significantly larger than the component speed.
description: 16 pages, 1 table, 3 color figures, accepted to the Astrophysical Journal
Σχεδιασμός αθροιστή κινητής υποδιαστολής για εφαρμογές FPGA.:
Creators: name: Παππά, Μυρτώ Ιωάννη
Publisher: name: Aristotle University of Thessaloniki
Year: 2011
Subjects: αριθμοί κινητής υποδιαστολής
δυαδικό σύστημα
Xilinx
Floating point numbers
binary system

description: Βασικός σκοπός της διπλωματικής αυτής εργασίας είναι η σχεδίαση και ανάπτυξη ενός αθροιστή αριθμών κινητής υποδιαστολής και παρουσίαση των επιδόσεών του στο περιβάλλον εργασίας Xilinx σε γλώσσα VHDL. Στην πρώτη ενότητα παρουσιάζεται η γλώσσα VHDL. Επιπλέον αναλύεται το δυαδικό αριθμητικό σύστημα, η πράξη της πρόσθεσης καθώς και η αναπαράσταση των δυαδικών αριθμών. Στη συνέχεια, παρουσιάζεται συνοπτικά το περιβάλλον Xilinx, το πρότυπο ΙΕΕΕ 754 (για αριθμούς κινητής υποδιαστολής) και ο αλγόριθμός πρόσθεσης δύο αριθμών κινητής υποδιαστολής 32 ψηφίων μονής ακρίβειας. Στο τέλος με τη βοήθεια των αναφορών οι οποίες προκύπτουν από το Xilinx παρουσιάζεται η επίδοση του αθροιστή.
description: The main goal of the present dissertation is to design and implement a floating point adder and in the end present its utilization with the help of the Xilinx suite. In the beginning, the primary characteristics of VHDL are described. Furthermore, the binary arithmetic system, the method of addition and the representation of binary numbers are analyzed. At the other sections there is a short presentation of the Xilinx environment and its primary tools. Furthermore, the IEEE 754 (floating point numbers) and the algorithm of adding two floating point numbers with single precision are described. In the end, the performance of the adder in the Xilinx suite is presented.
Las aguas transfronterizas: el escenario de la reflexión biomigratoria y est(ética)
Creators: name: Gallinal Moreno, Ana María
Publisher: name: Dykinson
Year: 2024
Subjects: art
migration
aesthetics

description: La gestión de las aguas transfronterizas requiere la cooperación internacional sobre los recursos hídricos y los flujos migratorios por el mar. La legislación de las cuencas transfronterizas marítimas desempeña un papel esencial en la regulación de las anunciadas biomigraciones masivas por el efecto del cambio climático y el desequilibrio en el acceso al agua. El principal objetivo de la investigación es establecer un paralelismo entre lo acuoso, la ética ecosocial y la estética artística a partir de los movimientos migratorios, con el fin de promover una distribución justa de las cargas ambientales; y abordar de manera integral y holística los retos multifacéticos que enfrenta la sociedad, derivados de las aguas mal gestionadas. El estudio aborda el concepto de transfrontera transdisciplinar (L. Taylor; E. Tigani) y el fenómeno ecosocial (M. Bookchin), desde la experiencia estética (I. Illich; G. Bachelard; M. Rivera). Se analizan las problemáticas asociadas a la desigualdad, en virtud de las barreras físicas y simbólicas relacionadas con el agua, protagonista del drama migrante. Si bien la humanidad ha incrementado los esfuerzos en la preservación de las reservas hidrológicas, igualmente, las sociedades actúan sobre la naturaleza adaptándola a sus necesidades creadoras, como medio para construir el pensamiento mítico y cósmico del mundo ligado a las aguas, tan creativas como destructoras.
On the origin of multifrequency temporal and spectral variability in Ton 599
Creators: name: Maurya, Sakshi
name: Majumdar, Joysankar
name: Varun
name: Sahu, Neetu
name: Prince, Raj
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: In this work, we studied the broadband temporal and spectral properties of the flat-spectrum radio quasar (FSRQ) Ton 599. We collected the long-term data from Jan 2019 to August 2024 when the source was in a long flaring episode. We used the Bayesian block methodology to identify the various flux states, including three flares. The broadband fractional variability is estimated during two flaring states. The Fvar variation with respect to frequency shows a nearly double hump structure similar to broadband SED. The Power spectral density (PSD) shows a pink-noise kind of stochastic variability in the light curve and we do not see any break in the power spectrum, suggesting a much longer characteristic time scale is involved in gamma-ray variability. The flux distribution is well-fitted with a double log-normal flux distribution, suggesting the variability of non-linear in nature. The gamma-ray, optical, and X-ray emissions were found to be highly correlated with a zero time lag, suggesting a co-spatial origin of their emissions. We used the one-zone leptonic model to reproduce the broad-band spectrum in the energy range from IR to very high-energy gamma-ray. The increase in the magnetic field and the Doppler factor were found to be the main cause for high flux states. The XMM-Newton spectra taken during one of the flaring durations exhibit a signature of thermal black body emission from the accretion disk, suggesting a possible disk-jet coupling. This has also been indicated by the gamma-ray flux distribution, which shows the distribution as non-linear in nature, which is mostly seen in galactic X-ray binaries or AGN where the accretion disk dominates the emission.
description: Accepted for Publication in PASA journal
Long-range memory model of trading activity and volatility
Creators: name: Gontis, V.
name: Kaulakys, B.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Statistical Finance (q-fin.ST)
subject: FOS: Physical sciences
subject: FOS: Economics and business

description: Earlier we proposed the stochastic point process model, which reproduces a variety of self-affine time series exhibiting power spectral density S(f) scaling as power of the frequency f and derived a stochastic differential equation with the same long range memory properties. Here we present a stochastic differential equation as a dynamical model of the observed memory in the financial time series. The continuous stochastic process reproduces the statistical properties of the trading activity and serves as a background model for the modeling waiting time, return and volatility. Empirically observed statistical properties: exponents of the power-law probability distributions and power spectral density of the long-range memory financial variables are reproduced with the same values of few model parameters.
description: 12 pages, 5 figures
Massive Black Holes: formation and evolution
Creators: name: Rees, Martin J.
name: Volonteri, Marta
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Supermassive black holes are nowadays believed to reside in most local galaxies. Observations have revealed us vast information on the population of local and distant black holes, but the detailed physical properties of these dark massive objects are still to be proven. Accretion of gas and black hole mergers play a fundamental role in determining the two parameters defining a black hole: mass and spin. We briefly review here the basic properties of the population of supermassive black holes, focusing on the still mysterious formation of the first massive black holes, and their evolution from early times to now.
description: review to appear in Proc. IAU Symp. 238, "Black Holes: from stars to galaxies - across the range of masses"
DEN-IM: dengue virus identification from metagenomic sequencing data
Creators: name: C I Mendes
name: E Lizarazo
name: M P Machado
name: D N Silva
name: A Tami
name: M Ramirez
name: N Couto
name: J W A Rossen
name: J A  Carriço
Publisher: name: F1000 Research Limited
Year: 2019

description: Background: Dengue virus (DENV) posses a public health challenge where infection is endemic. To follow viral evolution and its impact on human health, high throughput sequencing technologies (HTS) are of great value in the molecular characterization of viruses causing the infections. However, bioinformatic expertise and appropriate computing infrastructure are required for accurate HTS data analysis and interpretation of the sequencing data.
Materials/Methods: We developed DEN-IM, an automated workflow enabling the analysis of metagenomic sequencing data for identification, serotyping, genotyping, and phylogenetic analysis of DENV (Figure 1). To identify DENV reads and to perform sero- and genotyping, a curated database containing 3818 complete DENV genomes was compiled. As input DEN-IM accepts raw paired-end Illumina sequencing reads and provides the user with an interactive HTML report.
DEN-IM was implemented in Nextflow alongside Docker containers to facilitate installation and can be executed in local machines or high performance computing facilities. To evaluate DEN-IM workflow performance and accuracy, we have analysed a dataset containing 25 metagenomic sequencing samples, including positive and negative controls and a spiked sample with 4 different strains.
Results: For the HTS data, a full ORF was obtained in 84% of the samples, including the spiked sample where 4 distinct ORFs were obtained belonging to the 4 different DENV serotypes. The samples included serotype 1 genotype V (8.3%), serotype 2 genotype asian-american (37.5%), serotype 3 genotype III (20.8%), and serotype 4 genotype II (33%).
Two samples failed the quality control check due to low number of sequenced reads, one of these samples being the negative control. Additionally, two samples failed to assemble a full ORF due to very small amount of DENV reads present in these samples (0.05% and 0.01% respectively).
Conclusions: DEN-IM enables recovery, identification and typing of DENV with high accuracy from samples with as little as 1% DENV reads. DEN-IM is conceived as a one-stop solution for the analysis of raw sequencing data, enabling reproducible and collaborative research that benefits a wide group of researchers regardless of their computational expertise and available resources. The DEN-IM workflow and documentation are available at https://github.com/B-UMMI/DEN-IM.
On bounded solutions of a problem of R. Schilling
Creators: name: Morawiec, Janusz
Publisher: name: arXiv
Year: 2008
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Mathematics
subject: 39B12, 39B22 (Primary)

description: The paper deals with locally bounded solutions of a Schilling's problem.
description: 6 pages
title: Recruitment to the northern stock of Pacific sardine (Sardinops sagax) in the California Current and its relationship to the Pacific Decadal Oscillation
Creators: name: Zwolinski, Juan P.
name: Demer, David A.
Publisher: name: ASC 2013 - Theme session M
Year: 2024
Subjects: Technologies and data
Ecosystem observation, processes and dynamics

description: No abstracts are to be cited without prior reference to the author. We confirm that sardine recruitment in the California Current, during the last three decades, mimics aspects of the environment in the North Pacific indicated by the Pacific Decadal Oscillation index (PDO).
Local existence of solutions to the initial-value problem for one-dimensional strain-limiting viscoelasticity
Creators: name: Erbay, Husnu A.
name: Erkip, Albert
name: Sengul, Yasemin
Publisher: name: arXiv
Year: 2020
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: In this work we prove local existence of strong solutions to the initial-value problem arising in one-dimensional strain-limiting viscoelasticity, which is based on a nonlinear constitutive relation between the linearized strain, the rate of change of the linearized strain and the stress. The model is a generalization of the nonlinear Kelvin-Voigt viscoelastic solid under the assumption that the strain and the strain rate are small. We define an initial-value problem for the stress variable and then, under the assumption that the nonlinear constitutive function is strictly increasing, we convert the problem to a new form for the sum of the strain and the strain rate. Using the theory of variable coefficient heat equation together with a fixed point argument we prove local existence of solutions. Finally, for several constitutive functions widely used in the literature we show that the assumption on which the proof of existence is based is not violated.
Linear response theory for a pair of coupled one-dimensional condensates of interacting atoms
Creators: name: Gritsev, Vladimir
name: Polkovnikov, Anatoli
name: Demler, Eugene
Publisher: name: arXiv
Year: 2007
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We use quantum sine-Gordon model to describe the low energy dynamics of a pair of coupled one-dimensional condensates of interacting atoms. We show that the nontrivial excitation spectrum of the quantum sine-Gordon model, which includes soliton and breather excitations, can be observed in experiments with time-dependent modulation of the tunneling amplitude, potential difference between condensates, or phase of tunneling amplitude. We use the form-factor approach to compute structure factors corresponding to all three types of perturbations.
description: 11 pages, 7 figures