cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Intracavity optogalvanic spectroscopy for radiocarbon analysis with attomole sensitivity
Creators: name: Ilkmen, Erhan
Publisher: name: No Publisher Supplied
Year: 2009

description: Carbon-14 (radiocarbon) is a naturally occurring radioactive isotope of carbon, having an extremely low natural abundance in living organisms (14C/C ~ 10-12) and a long half life of ~ 5730 years. These properties make it an ideal organic tracer for various applicationsin biological, pharmaceutical and environmental sciences as well as carbon dating. Today, the state of the art radiocarbon quantitation technique is Accelerator Mass Spectrometry (AMS) which is based on ion counting using a several megavolt tandem electrostatic accelerator as a mass spectrometer. Although AMS sets the standard for high sensitivity detection, its size, cost and complexity as an analysis system, limits its wide and routine use especially in laboratory or field applications. In this thesis, a new ultrasensitivelaser based analytical technique that can quantify attomoles of 14C in submicrogram samples is demonstrated. The new system exhibits similar or bettermeasurement capabilities as AMS, in sensitivity (14C/C ≤ 10-15), precision (≤3%) and accuracy (≤5%). Additional advantages include non destructive analysis capability, small size, being a table top instrument, high sample throughput capability via flow processingand the potential to be coupled to GC/LC instrumentation.The developed Intracavity Optogalvanic Spectroscopy (ICOGS) system is based on measuring changes in electrical properties of a weakly ionized glow discharge placed inside the cavity of a periodically modulated high power (50 W) 14CO2 laser. This new configuration enabled improvement of the signal detection sensitivity by about six orders of magnitude compared to the conventional external cell optogalvanic spectroscopymethod. The signal enhancement mechanism is similar to, but with key differences from the well studied optical detection method Intracavity Absorption Spectroscopy (ICAS). Measurement capability of this new system is demonstrated with calibration curvesrelative to AMS measurements with a dynamic range of more than five orders of magnitude. The systems studied exhibited saturation effects with laser power andmeasurement time and also non-linearities in response with samples having enrichments greater than 12 Modern. (1 Modern = 1.10-12 14C/12C ratio.) However, standard operating procedures were developed for accurately measuring unknown samples. For a more thorough quantitative understanding of the enhancement mechanism, a physical rate equations model has been outlined.
A New Topological "Twist" to BR Scaling
Creators: name: Rho, Mannque
Publisher: name: arXiv
Year: 2014
Subjects: subject: Nuclear Theory (nucl-th)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: When vector mesons are considered on the same footing as pions as suggested by hidden local symmetry, the property of the nuclear tensor forces is strongly controlled by the behavior of the vector mesons in dense medium. This led to BR scaling in 1991. When baryons as skyrmions are put on crystal, there can be a phase transition from skyrmions to half-skyrmions at a density above that of normal nuclear matter. This topology change can induce fundamental changes to the parameters in hidden local symmetric Lagrangian, hence BR scaling, and brings a drastic modification to the structure of nuclear forces, in particulrar, the tensor forces. This can have far-reaching consequences on the EoS of compact-star matter and the structure of neutron-rich nuclei.
description: 13 pages, 1 figure
A new type of localized fast moving electronic excitations in molecular chains
Creators: name: Korshunova, A. N.
name: Lakhno, V. D.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: It is shown that in a Holstein molecular chain placed in a strong longitudinal electric field some new types of excitations can arise. This excitations can transfer a charge over large distance (more than 1000 nucleotide pairs) along the chain retaining approximately their shapes. Excitations are formed only when a strong electric field either exists or quickly arises under especially preassigned conditions. These excitations transfer a charge even in the case when Holstein polarons are practically immobile. The results obtained are applied to synthetic homogeneous PolyG/PolyC DNA duplexes. They can be also provide the basis for explanation of famous H.W. Fink and C. Schönenberger experiment on long-range charge transfer in DNA.
description: 4 pages, 3 figures
Axial asymmetry in the IVBM
Creators: name: Ganev, H. G.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The dynamical symmetry limit of the two-fluid Interacting Vector Boson Model (IVBM), defined through the chain $Sp(12,R) \supset U(3,3) \supset U_{p}(3) \otimes \overline{U_{n}(3)} \supset SU^{\ast}(3) \supset SO(3)$, is considered and applied for the description of nuclear collective spectra exhibiting axially asymmetric features. The effect of the introduction of a Majorana interaction to the $SU^{\ast}(3)$ model Hamiltonian on the $γ$-band energies is studied. The theoretical predictions are compared with the experimental data for $^{192}Os$, $^{190}Os$, and $^{112}Ru$ isotopes. It is shown that by taking into account the full symplectic structures in the considered dynamical symmetry of the IVBM, the proper description of the energy spectra and the $γ$-band energy staggering of the nuclei under considerations can be achieved. The obtained results show that the potential energy surfaces for the following two nuclei $^{192}Os$ and $^{112}Ru$, possess almost $γ$-flat potentials with very shallow triaxial minima, suggesting a more complex and intermediate situation between $γ$-rigid and $γ$-unstable structures. Additionally, the absolute $B(E2)$ intraband transition probabilities between the states of the ground state band and $γ$ band, as well as the $B(M1)$ interband transition probabilities between the states of the ground and $γ$ bands for the two nuclei $^{192}Os$ and $^{190}Os$ are calculated and compared with experiment and for the $B(E2)$ values with the predictions of some other collective models incorporating the $γ$-rigid or $γ$-unstable structures. The obtained results agree well with the experimental data and reveal the relevance of the used dynamical symmetry of IVBM in the description of nuclei exhibiting axially asymmetric features in their spectra.
description: 10 pages, 10 figures. arXiv admin note: text overlap with arXiv:1402.1742
Componentized hierarchical build and test infrastructure and processes for CASL VERA
Creators: name: Bartlett, Roscoe
Publisher: name: figshare
Year: 2020
Subjects: subject: 80309 Software Engineering
subject: FOS: Computer and information sciences
subject: Computer Software
subject: 80204 Mathematical Software

description: Developing, testing, and deploying complex computational science and engineering (CSE) software created by distributed teams is a daunting endeavor. This was well demonstrated in the Consortium of the Advanced Simulation of Light-water reactors (CASL) project. The CASL Virtual Environment for Reactor Applications (VERA) software integrates the development efforts of many different teams, code bases, and institutions into multi-physics executables. The software engineering and process challenges to achieve an integrated product that is continuously upgraded with new contributions are enormous. While the modern software engineering (SE) community has made great strides in developing principles, processes and best practices to manage such projects, it takes non-trivial tools to effectively implement such processes. In addition, just the mechanics of configuring, building, and installing complex compiled multi-language software on a variety of platforms is very challenging. Today's CSE software must be able to be run on platforms ranging from basic Linux workstations and Microsoft Windows machines to the largest bleeding-edge massively parallel supercomputers.
In order to address these challenges, a framework called the Tribal Build, Integration, and Test System (TriBITS) was constructed and applied to VERA. TriBITS creates an organized framework built on top of (and implemented using) the Kitware CMake tools to handle a potentially large number of semi-independent development efforts while still allowing for seamless integration and deployment for large stacks of related software. At the low end, TriBITS can be used to quickly develop a small independent software product with all the bells and whistles of agile software development including pre-push and post-push continuous integration. At the high end (such as with VERA), TriBITS can be used as a meta-build, testing and deployment system to integrate several smaller semi-independent TriBITS-enabled software projects. TriBITS is focused on the development and deployment of software written using primarily the compiled languages C, C++, Fortran -- and mixed-language programs involving these -- which use MPI and various local threading approaches to achieve performant parallel computation.
Transient jet formation and state transitions from large-scale magnetic reconnection in black hole accretion discs
Creators: name: Dexter, Jason
name: McKinney, Jonathan C.
name: Markoff, Sera
name: Tchekhovskoy, Alexander
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Magnetically arrested accretion discs (MADs), where the magnetic pressure in the inner disc is dynamically important, provide an alternative mechanism for regulating accretion to what is commonly assumed in black hole systems. We show that a global magnetic field inversion in the MAD state can destroy the jet, significantly increase the accretion rate, and move the effective inner disc edge in to the marginally stable orbit. Reconnection of the MAD field in the inner radii launches a new type of transient outflow containing hot plasma generated by magnetic dissipation. This transient outflow can be as powerful as the steady magnetically-dominated Blandford-Znajek jet in the MAD state. The field inversion qualitatively describes many of the observational features associated with the high luminosity hard to soft state transition in black hole X-ray binaries: the jet line, the transient ballistic jet, and the drop in rms variability. These results demonstrate that the magnetic field configuration can influence the accretion state directly, and hence the magnetic field structure is an important second parameter in explaining observations of accreting black holes across the mass and luminosity scales.
description: 5 pages, 3 figures, submitted to MNRAS Letters
Beam energy determination in experiments at electron-positron colliders
Creators: name: Achasov, M. N.
name: Muchnoi, N. Yu.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Accelerator Physics (physics.acc-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: The review of using of compton backscattering method for determination of the beam energy in collider experiments is given.
description: 15 pages, 14 figures, talk given at International Conference on Instrumentation for Colliding Beam Physics, February 24 - March 1, 2014, Novosibirsk, Russia
Concatenating a gridded rainfall reanalysis dataset into a time series (Jupyter Notebook) published in the Environmental Data Science book - snapshot
Creators: Samantha Adams
Timothy Lam
Rachel Prudden
Alejandro Coca-Castro
Marlene Kretschmer
Elena Saggioro
Nick Homer
Publisher: name: Environmental Data Science Book Community
Year: 2022

description: The research object refers to the Concatenating a gridded rainfall reanalysis dataset into a time series notebook published in the Environmental Data Science book.
Content Based Image Indexing and Retrieval
Creators: name: Bhute, Avinash N
name: Meshram, B. B.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Graphics (cs.GR)
subject: Information Retrieval (cs.IR)
subject: Multimedia (cs.MM)
subject: FOS: Computer and information sciences

description: In this paper, we present the efficient content based image retrieval systems which employ the color, texture and shape information of images to facilitate the retrieval process. For efficient feature extraction, we extract the color, texture and shape feature of images automatically using edge detection which is widely used in signal processing and image compression. For facilitated the speedy retrieval we are implements the antipole-tree algorithm for indexing the images.
description: 12 pages
Lawan Virus Covid-19 dengan Memanfaatkan Senyawa Metabolit Sekunder Flavonoid dalam Daun Jeruk Nipis
Creators: name: Awalia, Nida
Publisher: name: Zenodo
Year: 2020
Subjects: Daun Jeruk Nipis

description: artikel yang ditulis dengan mengacu dari beberapa e-book dan jurnal
Real-time single-molecule imaging of quantum interference
Creators: name: Juffmann, Thomas
name: Milic, Adriana
name: Müllneritsch, Michael
name: Asenbaum, Peter
name: Tsukernik, Alexander
name: Tüxen, Jens
name: Mayor, Marcel
name: Cheshnovsky, Ori
name: Arndt, Markus
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Physics (quant-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: The observation of interference patterns in double-slit experiments with massive particles is generally regarded as the ultimate demonstration of the quantum nature of these objects. Such matter-wave interference has been observed for electrons, neutrons, atoms and molecules and it differs from classical wave-physics in that it can even be observed when single particles arrive at the detector one by one. The build-up of such patterns in experiments with electrons has been described as the "most beautiful experiment in physics". Here we show how a combination of nanofabrication and nanoimaging methods allows us to record the full two-dimensional build-up of quantum diffraction patterns in real-time for phthalocyanine molecules PcH2 and their tailored derivatives F24PcH2 with a mass of 1298 amu. A laser-controlled micro-evaporation source was used to produce a beam of molecules with the required intensity and coherence and the gratings were machined in 10 nm thick silicon nitride membranes to reduce the effect of van der Waals forces. Wide-field fluorescence microscopy was used to detect the position of each molecule with an accuracy of 10 nm and to reveal the build-up of a deterministic ensemble interference pattern from stochastically arriving and internally hot single molecules.
description: Related video: http://www.youtube.com/watch?v=wDx8tu-iX8U
BTZ Black Hole Entropy and the Turaev-Viro model
Creators: name: Geiller, Marc
name: Noui, Karim
Publisher: name: arXiv
Year: 2013
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We show the explicit agreement between the derivation of the Bekenstein-Hawking entropy of a Euclidean BTZ black hole from the point of view of spin foam models and canonical quantization. This is done by considering a graph observable (corresponding to the black hole horizon) in the Turaev-Viro state sum model, and then analytically continuing the resulting partition function to negative values of the cosmological constant.
description: 22+4 pages, 3 figures
Enhancement of the magnetocaloric effect driven by changes in the crystal structure of Al doped GGG, Gd3Ga5-xAlxO12 (0 < x < 5)
Creators: name: Hamilton, A. C. Sackville
name: Lampronti, G. I.
name: Rowley, S. E.
name: Dutton, S. E.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The Gd3Ga5-xAlxO12 (0 < x < 5) solid solution has been prepared using ceramic synthesis routes and the structural and magnetic properties investigated using X-ray diffraction, magnetic susceptibility, chi, and isothermal magnetisation, M(H), measurements. Our results indicate a contraction of the unit cell and more significant antiferromagnetic interactions as x increases. Despite the decrease in the magnetic polarisation on application of a field and the corresponding decrease in the change in the magnetic entropy we find that Gd3Al5O12 has a significantly higher observed (17%) and theoretical (14%) DS per unit mass than Gd3Ga5O12. Per unit volume the theoretical increase in DS (7%) is offset by the increased antiferromagnetic interactions in Gd3Al5O12. The differences in DS are driven by a decrease in both the mass and density as Al ions replace Ga ions. These results highlight the importance of changes to the crystal structure when considering materials for solid state magnetic cooling.
description: 16 pages, 4 figures accepted for publication in J. Phys.: Cond. Mat
On central limit theorems in the random connection model
Creators: name: van de Brug, Tim
name: Meester, Ronald
Publisher: name: arXiv
Year: 2014
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 60K35

description: Consider a sequence of Poisson random connection models (X_n,lambda_n,g_n) on R^d, where lambda_n / n^d \to lambda > 0 and g_n(x) = g(nx) for some non-increasing, integrable connection function g. Let I_n(g) be the number of isolated vertices of (X_n,lambda_n,g_n) in some bounded Borel set K, where K has non-empty interior and boundary of Lebesgue measure zero. Roy and Sarkar [Phys. A 318 (2003), no. 1-2, 230-242] claim that (I_n(g) - E I_n(g)) / \sqrt Var I_n(g) converges in distribution to a standard normal random variable. However, their proof has errors. We correct their proof and extend the result to larger components when the connection function g has bounded support.
description: 17 pages, 3 figures
Imaging and characterization of conducting ferroelectric domain walls by photoemission electron microscopy
Creators: name: Schaab, J.
name: Krug, I. P.
name: Nickel, F.
name: Gottlob, D. M.
name: Doğanay, H.
name: Cano, A.
name: Hentschel, M.
name: Yan, Z.
name: Bourret, E.
name: Schneider, C. M.
name: Ramesh, R.
name: Meier, D.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: High-resolution X-ray photoemission electron microscopy (X-PEEM) is a well-established method for imaging ferroelectric domain structures. Here, we expand the scope of application of X-PEEM and demonstrate its capability for imaging and investigating domain walls in ferroelectrics with high-spatial resolution. Using ErMnO3 as test system, we show that ferroelectric domain walls can be visualized based on photo-induced charging effects and local variations in their electronic conductance can be mapped by analyzing the energy distribution of photoelectrons. Our results open the door for non-destructive, contract-free, and element-specific studies of the electronic and chemical structure at domain walls in ferroelectrics.
Redshift drift test of exotic singularity universes
Creators: name: Denkiewicz, Tomasz
name: Dabrowski, Mariusz P.
name: Martins, Carlos J. A. P.
name: Vielzeuf, Pauline
Publisher: name: arXiv
Year: 2014
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We discuss how dynamical dark energy universes with exotic singularities may be distinguished from the standard $Λ$CDM model on the basis of their redshift drift signal, for which measurements both in the acceleration phase and in the deep matter era will be provided by forthcoming astrophysical facilities. Two specific classes of exotic singularity models are studied: sudden future singularity models and finite scale factor singularity models. In each class we identify the models which can mimic $Λ$CDM and play the role of dark energy as well as models for which redshift drift signals are significantly different from $Λ$CDM and the test can differentiate between them.
description: 6 pages, 8 figures, Revtex 4-1, references added
Population dynamics with nonlinear delayed carrying capacity
Creators: name: Yukalov, V. I.
name: Yukalova, E. P.
name: Sornette, D.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Biological sciences
subject: FOS: Physical sciences

description: We consider a class of evolution equations describing population dynamics in the presence of a carrying capacity depending on the population with delay. In an earlier work, we presented an exhaustive classification of the logistic equation where the carrying capacity is linearly dependent on the population with a time delay, which we refer to as the "linear delayed carrying capacity" model. Here, we generalize it to the case of a nonlinear delayed carrying capacity. The nonlinear functional form of the carrying capacity characterizes the delayed feedback of the evolving population on the capacity of their surrounding by either creating additional means for survival or destroying the available resources. The previously studied linear approximation for the capacity assumed weak feedback, while the nonlinear form is applicable to arbitrarily strong feedback. The nonlinearity essentially changes the behavior of solutions to the evolution equation, as compared to the linear case. All admissible dynamical regimes are analyzed, which can be of the following types: punctuated unbounded growth, punctuated increase or punctuated degradation to a stationary state, convergence to a stationary state with sharp reversals of plateaus, oscillatory attenuation, everlasting fluctuations, everlasting up-down plateau reversals, and divergence in finite time. The theorem is proved that, for the case characterizing the evolution under gain and competition, solutions are always bounded, if the feedback is destructive. We find that even a small noise level profoundly affects the position of the finite-time singularities. Finally, we demonstrate the feasibility of predicting the critical time of solutions having finite-time singularities from the knowledge of a simple quadratic approximation of the early time dynamics.
description: Latex file, 24 pages
AME - Asteroseismology Made Easy. Estimating stellar properties by use of scaled models
Creators: name: Lundkvist, M.
name: Kjeldsen, H.
name: Aguirre, V. Silva
Publisher: name: arXiv
Year: 2014
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present a new method to obtain stellar properties for stars exhibiting solar-like oscillations in an easy, fast, and transparent way. The method, called Asteroseismology Made Easy (AME), can determine stellar masses, mean-densities, radii, and surface gravities, as well as estimate ages. In this writing we present AME as a visual and powerful tool which could be useful; in particular in the light of the large number of exoplanets being found. AME consists of a set of figures from which the stellar parameters are deduced. These figures are made from a grid of stellar evolutionary models that cover masses ranging from 0.7 Msun to 1.6 Msun in steps of 0.1 Msun and metallicities in the interval -0.3 dex <= [Fe/H] <= +0.3 dex in increments of 0.1 dex. The stellar evolutionary models are computed using the Modules for Experiments in Stellar Astrophysics (MESA) code with simple input physics. We have compared the results from AME with results for three groups of stars; stars with radii determined from interferometry (and measured parallaxes), stars with radii determined from measurements of their parallaxes (and calculated angular diameters), and stars with results based on the modelling of their individual oscillation frequencies. We find that a comparison of the radii from interferometry to those from AME yield a weighted mean of the fractional differences of just 2%. This is also the level of deviation that we find when we compare the parallax-based radii to the radii determined from AME. The comparison between independently determined stellar parameters and those found using AME show that our method can provide reliable stellar masses, radii, and ages, with median uncertainties in the order of 4%, 2%, and 25% respectively.
description: 18 pages, 25 figures. To be published in Astronomy & Astrophysics
The LOFT mission: new perspectives in the research field of (accreting) compact objects
Creators: name: Bozzo, E.
name: Stella, L.
name: van der Klis, M.
name: Watts, A.
name: Barret, D.
name: Wilms, J.
name: Uttley, P.
name: Herder, J. W. den
name: Feroci, M.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: LOFT, the Large Observatory For X-ray Timing, is one of five ESA M3 candidate missions. It will address the Cosmic Vision theme: "Matter under Extreme Conditions". By coupling for the first time a huge collecting area for the detection of X-ray photons with CCD-quality spectral resolution (15 times bigger in area than any previously flown X-ray instrument and >100 times bigger for spectroscopy than any similar-resolution instrument), the instruments on-board LOFT have been designed to (i) determine the properties of ultradense matter by reconstructing its Equation of State through neutron star mass and radius measurements of unprecedented accuracy; (ii) measure General Relativity effects in the strong field regime in the stationary spacetimes of neutron stars and black holes of all masses down to a few gravitational radii. Besides the above two themes, LOFT's observations will be devoted to "observatory science", providing new insights in a number of research fields in high energy astrophysics (e.g. Gamma-ray Bursts). The assessment study phase of LOFT, which ended in September 2013, demonstrated that the mission is low risk and the required Technology Readiness Level can be easily reached in time for a launch by the end of 2022.
description: To appear in proceedings of "Physics at the Magnetospheric Boundary" (Geneva, Switzerland, 25-28 June 2013)
Perfect state transfer on distance-regular graphs and association schemes
Creators: name: Coutinho, Gabriel
name: Godsil, Chris
name: Guo, Krystal
name: Vanhove, Frédéric
Publisher: name: arXiv
Year: 2014
Subjects: subject: Combinatorics (math.CO)
subject: Quantum Physics (quant-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: We consider the representation of a continuous-time quantum walk in a graph $X$ by the matrix $\exp(itA(X))$. We provide necessary and sufficient criteria for distance-regular graphs and, more generally, for graphs in association schemes to have perfect state transfer. Using these conditions, we provide several new examples of perfect state transfer in simple graphs.
description: 32 pages
Extinction Maps towards the Milky Way Bulge: 2D and 3D Tests with APOGEE
Creators: name: Schultheis, M.
name: Zasowski, G.
name: Prieto, C. Allende
name: Anders, F.
name: Beaton, R. L.
name: Beers, T. C.
name: Bizyaev, D.
name: Chiappini, C.
name: Frinchaboy, P. M.
name: Garcia-Perez, A. E.
name: Ge, J.
name: Hearty, F.
name: Holtzman, J.
name: Majewski, S. R.
name: Muna, D.
name: Nidever, D.
name: Shetrone, M.
name: Schneider, D. P.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Galactic interstellar extinction maps are powerful and necessary tools for Milky Way structure and stellar population analyses, particularly toward the heavily-reddened bulge and in the midplane. However, due to the difficulty of obtaining reliable extinction measures and distances for a large number of stars that are independent of these maps, tests of their accuracy and systematics have been limited. Our goal is to assess a variety of photometric stellar extinction estimates, including both 2D and 3D extinction maps, using independent extinction measures based on a large spectroscopic sample of stars towards the Milky Way bulge. We employ stellar atmospheric parameters derived from high-resolution $H$-band APOGEE spectra, combined with theoretical stellar isochrones, to calculate line-of-sight extinction and distances for a sample of more than 2400 giants towards the Milky Way bulge. We compare these extinction values to those predicted by individual near-IR and near+mid-IR stellar colors, 2D bulge extinction maps and 3D extinction maps. The long baseline, near+mid-IR stellar colors are, on average, the most accurate predictors of the APOGEE extinction estimates, and the 2D and 3D extinction maps derived from different stellar populations along different sightlines show varying degrees of reliability. We present the results of all of the comparisons and discuss reasons for the observed discrepancies. We also demonstrate how the particular stellar atmospheric models adopted can have a strong impact on this type of analysis, and discuss related caveats.
description: 10 pages, 12 pages, accepted for publication in AJ
Bounds for the modified eccentric connectivity index
Creators: name: De, Nilanjan
name: Nayeem, Sk. Md. Abu
name: Pal, Anita
Publisher: name: arXiv
Year: 2014
Subjects: subject: Combinatorics (math.CO)
subject: Discrete Mathematics (cs.DM)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences
subject: J.2; G.2.m
subject: Primary: 05C35, Secondary: 05C07, 05C40

description: The modified eccentric connectivity index of a graph is defined as the sum of the products of eccentricity with the total degree of neighboring vertices, over all vertices of the graph. This is a generalization of eccentric connectivity index. In this paper, we derive some upper and lower bounds for the modified eccentric connectivity index in terms of some graph parameters such as number of vertices, number of edges, radius, minimum degree, maximum degree, total eccentricity, the first and second Zagreb indices, Weiner index etc.
description: 10 pages
Density Functional Theory for Hard Particles in N Dimensions
Creators: name: Korden, Stephan
Publisher: name: arXiv
Year: 2014
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: Recently it has been shown that the heuristic Rosenfeld functional derives from the virial expansion for particles which overlap in one center. Here, we generalize this approach to any number of intersections. Starting from the virial expansion in Ree-Hoover diagrams, it is shown in the first part that each intersection pattern defines exactly one infinite class of diagrams. Determining their automorphism groups, we sum over all its elements and derive a generic functional. The second part proves that this functional factorizes into a convolute of integral kernels for each intersection center. We derive this kernel for N dimensional particles in the N dimensional, flat Euclidean space. The third part focuses on three dimensions and determines the functionals for up to four intersection centers, comparing the leading order to Rosenfeld's result. We close by proving a generalized form of the Blaschke, Santalo, Chern equation of integral geometry.
description: 2 figures
Mergers as triggers for nuclear activity: A near-IR study of the close environment of AGN in the VISTA-VIDEO survey
Creators: name: Karouzos, Marios
name: Jarvis, Matt J.
name: Bonfield, David
Publisher: name: arXiv
Year: 2013
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: There is an ongoing debate concerning the driver of nuclear activity in galaxies, with AGN either being triggered by major or minor galactic mergers or, alternatively, through secular processes like cooling gas accretion and/or formation of bars. We investigate the close environment of active galaxies selected in the X-ray, the radio, and the mid-IR. We utilise the first data release of the new near-IR VISTA Deep Extragalactic Observations (VIDEO) survey of the XMM-Large Scale Structure (LSS) field. We use two measures of environment density, namely counts within a given aperture and a finite redshift slice (pseudo-3D density) and closest neighbour density measures $Σ_{2}$ and $Σ_{5}$. We select both AGN and control samples, matching them in redshift and apparent Ks-band magnitude. We find that AGN are found in a range of environments, with a subset of the AGN samples residing in over-dense environments. Seyfert-like X-ray AGN and flat-spectrum radio-AGN are found to inhabit significantly over-dense environments compared to their control sample. The relation between over-densities and AGN luminosity does not however reveal any positive correlation. Given the absence of an environment density-AGN luminosity relation,we find no support for a scheme where high luminosity AGN are preferentially triggered by mergers. On the contrary, we find that AGN likely trace over dense environments at high redshift due to the fact that they inhabit the most massive galaxies, rather than being an AGN.
description: 19 pages, 25 figures, submitted to MNRAS
On the origin of the peculiar cataclysmic variable AE Aquarii
Creators: name: Beskrovnaya, N. G.
name: Ikhsanov, N. R.
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The nova-like variable AE Aquarii is a close binary system containing a red dwarf and a magnetized white dwarf rotating with the period of 33 seconds. A short spin period of the white dwarf is caused by an intensive mass exchange between the system components during a previous epoch. We show that a high rate of disk accretion onto the white dwarf surface resulted in temporary screening of its magnetic field and spin-up of the white dwarf to its present spin period. Transition of the white dwarf to the ejector state occurred at a final stage of the spin-up epoch after its magnetic field had emerged from the accreted plasma due to diffusion. In the frame of this scenario AE Aqr represents a missing link in the chain of Polars evolution and the white dwarf resembles a recycled pulsar.
description: 8 pages, accepted for publication in "Advances in Space Research". arXiv admin note: substantial text overlap with arXiv:1205.4330
Testing the Perey Effect
Creators: name: Titus, L. J.
name: Nunes, F. M.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Nuclear Theory (nucl-th)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: Background: The effects of non-local potentials have historically been approximately included by applying a correction factor to the solution of the corresponding equation for the local equivalent interaction. This is usually referred to as the Perey correction factor. Purpose: In this work we investigate the validity of the Perey correction factor for single-channel bound and scattering states, as well as in transfer (p,d) cross sections. Method: We solve the scattering and bound state equations for non-local interactions of the Perey-Buck type, through an iterative method. Using the distorted wave Born approximation, we construct the T-matrix for (p,d) on 17O, 41Ca, 49Ca, 127Sn, 133Sn, and 209Pb at 20 and 50 MeV. Results: We found that for bound states, the Perey corrected wave function resulting from the local equation agreed well with that from the non-local equation in the interior region, but discrepancies were found in the surface and peripheral regions. Overall, the Perey correction factor was adequate for scattering states, with the exception of a few partial waves corresponding to the grazing impact parameters. These differences proved to be important for transfer reactions. Conclusions: The Perey correction factor does offer an improvement over taking a direct local equivalent solution. However, if the desired accuracy is to be better than 10%, the exact solution of the non-local equation should be pursued.
description: 12 pages, 8 figures
Information Theory and Image Understanding: An Application to Polarimetric SAR Imagery
Creators: name: Frery, A. C.
name: Nascimento, A. D. C.
name: Cintra, R. J.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Methodology (stat.ME)
subject: Statistics Theory (math.ST)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: This work presents a comprehensive examination of the use of information theory for understanding Polarimetric Synthetic Aperture Radar (PolSAR) images by means of contrast measures that can be used as test statistics. Due to the phenomenon called `speckle', common to all images obtained with coherent illumination such as PolSAR imagery, accurate modelling is required in their processing and analysis. The scaled multilook complex Wishart distribution has proven to be a successful approach for modelling radar backscatter from forest and pasture areas. Classification, segmentation, and image analysis techniques which depend on this model have been devised, and many of them employ some kind of dissimilarity measure. Specifically, we introduce statistical tests for analyzing contrast in such images. These tests are based on the chi-square, Kullback-Leibler, Rényi, Bhattacharyya, and Hellinger distances. Results obtained by Monte Carlo experiments reveal the Kullback-Leibler distance as the best one with respect to the empirical test sizes under several situations which include pure and contaminated data. The proposed methodology was applied to actual data, obtained by an E-SAR sensor over surroundings of We$β$ssling, Bavaria, Germany.
description: 15 pages, 11 figures
Density-dependent symmetry energy at subsaturation densities from nuclear mass differences
Creators: name: Fan, Xiaohua
name: Dong, Jianmin
name: Zuo, Wei
Publisher: name: arXiv
Year: 2014
Subjects: subject: Nuclear Theory (nucl-th)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: We extract the mass-dependent symmetry energy coefficients $a_{\text{sym}}({A})$ with the nuclear mass differences reducing the uncertainties as far as possible. The estimated $a_{\text{sym}}({A})$ of $^{208}\text{Pb}$ is $22.4\pm 0.3 $ MeV, which is further used to analyze the density-dependent nuclear matter symmetry energy at subsaturation densities. The slope parameter of the symmetry energy at the saturation density $ρ_{0}$ is $L=50.0\pm15.5$ MeV. Furthermore, it is found that, at the density of $ρ=0.69ρ_{0}=0.11$fm$^{-3}$, the symmetry energy $S(ρ=0.11\text{fm}^{-3})=25.98\pm0.01$ MeV and the correspondingly slope parameter is $L=49.6\pm6.2$ MeV, which are consistent with other independent analysis.
description: 4 pages, 1 figure
Absolute evaporation rates of non-rotating neutral PAH clusters
Creators: name: Montillaud, Julien
name: Joblin, Christine
Publisher: name: arXiv
Year: 2014
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Atomic and Molecular Clusters (physics.atm-clus)
subject: FOS: Physical sciences

description: Clusters of polycyclic aromatic hydrocarbons (PAHs) have been proposed as candidates for evaporating very small grains, which are thought to be precursors of free-flying PAHs. Evaporation rates have been calculated so far only for species containing up to a few 100 C atoms, whereas interstellar PAH clusters could contain up to ~1000 C atoms. We present a method that generalises the calculation of the statistical evaporation rate of large PAH clusters and provides rates for species containing up to ~1000 C-atoms. The evaporation of non-rotating neutral homo-molecular PAH clusters containing up to 12 molecules from a family of highly symmetric compact PAHs is studied. Statistical calculations were performed and completed with molecular dynamics simulations at high internal energies to provide absolute values for the evaporation rate and distributions of kinetic energy released. The calculations used explicit atom-atom Lennard-Jones potentials in the rigid molecule approximation. A new method is proposed to take both inter- and intra-molecular vibrations into account. Without any parameter adjustment, the calculated evaporation rates agree well with available experimental data. We find that the non-rotation assumption has a limited impact on the evaporation rates. The photostability of PAH clusters increases dramatically with the size of molecules in the clusters, and to a lesser extent with the number of molecules in the clusters. For values of the UV radiation field that are typical of the regions where evaporating very small grains are observed, the smallest clusters in this study (~50 C-atoms) are found to be quickly photo-evaporated, whereas the largest clusters (~1000 C-atoms) are photostable. Our results support the idea that large PAH clusters are good candidates for evaporating very small grains.
description: 13 pages, 10 figures
Biologically informed neural network identifies unfolded proteinrResponse as key pathway in critical COVID-19
Creators: name: Gavriilidis, George
name: Dimitsaki, Stella
name: Vasileiou, Vasileios
name: Psomopoulos, Fotis
Publisher: name: F1000 Research Limited
Year: 2022

description: COVID-19 multi-omics have been thoroughly analyzed with machine learning; however, the inference of therapeutically actionable insights has been hampered by highly dimensional biological data and poorly interpretable Artificial Intelligence components (10.1136/bmjinnov-2020-000648). Prior biomedical knowledge can significantly enhance neural networks applied on multi-omics since it can constrain the model from exploring unnecessary hypothesis spaces (https://doi.org/10.1093/bib/bbab454). Considering the above, we designed COV-PASnet which combines pathway-associated sparse deep neural network (PASnet) with explainable Artificial Intelligence Shapley values (https://doi.org/10.1371/journal.pone.0231166). COV-PASnet was able to robustly demarcate critical from non-critical COVID-19 cases (AUC:92%, F1-score: 69%) when applied on 2 large plasma proteomic datasets (training MGH: https://doi.org/10.1016/j.xcrm.2021.100287, testing DC: https://doi.org/10.1016/j.cell.2020.10.037). Strikingly, one of the most predictive pathways via pathway layers’ node ranking was the Unfolded Protein Response (UPR), mainly due to highly abundant Death Receptor 5 (DR5/TNFRSF10) (https://doi.org/10.1016/j.molcel.2017.06.017). Since the literature is scant for UPR signaling in coronaviruses, we next analyzed scRNA-seq data from COVID-19-patient-derived peripheral-blood mononuclear cells and discovered UPR-prone plasmablasts through Enrichr (GO:0036500, padj.<0.001) (doi: 10.1002/cpz1.90) and KEA3 (IRE1 kinase: 1st in critical COVID-19, 108th in non-critical cases based on MeanRank metric)( https://doi.org/10.1093/nar/gkab359). Overall, our herein work shows that our biologically informed neural network called COV-PASnet led to the identification of a previously unexplored tenet of critical COVID-19 in circulating plasmablasts called UPR signaling. Considering how important antibody secretion by plasmablasts is for COVID-19 clearance (https://doi.org/10.1016/j.cell.2020.08.025) and that persistent UPR via DR5 promotes apoptosis (10.1126/science.1254312), we believe that this pathway merits further pharmacological investigation, in the search of novel COVID-19 therapeutics.
Image‑based simulation of morphogen gradient formation during zebrafish epiboly.
Creators: name: Stark, Justina
name: Rohit Krishnan Harish
name: Brand, Michael
name: Sbalzarini, Ivo F.
Publisher: name: F1000 Research Limited
Year: 2022

description: Graded concentration fields of morphogens are crucial during embryonic development, as they provide positional information for cell differentiation and tissue morphogenesis. Yet, how exactly these morphogen gradients are formed and maintained remains poorly understood. This is due to the abundance of factors involved, including localized sources and sinks, interaction with extracellular matrix molecules, and complex 3D tissue shapes.

 Mathematical and computational models can help understand the role each factor plays. Many of the existing models, however, neglect the complex and dynamic tissue shape and reduce dimensionality to 2D or even 1D, although it is known that 3D geometry has a significant impact on morphogen gradient formation.

 We address this gap by deriving a realistic 3D computational model of a zebrafish embryo during epiboly from light‑sheet microscopy volumes. We use this image‑based model to simulate Fgf8a and Fgf3 gradient formation in the dynamically deforming extracellular space, as the embryo undergoes epiboly.

 Our simulation numerically solves continuous reaction-diffusion equations in order to test whether the source‑diffusion‑sink model, which has been assumed so far, is sufficient to explain the shapes of the morphogen gradients observed. In particular, we show how the gradient is coupled to different factors, like tissue shape, production and degradation rates, location and surface area of source and sink, as well as the interaction with the extracellular matrix.

 This presents a complete image‑based simulation workflow that helps understand the mechanisms underlying morphogen gradient formation in the complex and deforming shapes of a growing embryo.
The Pressure of the Star Forming ISM in Cosmological Simulations
Creators: name: Munshi, Ferah
name: Christensen, Charlotte
name: Quinn, Thomas R.
name: Governato, Fabio
name: Wadsley, James
name: Loebman, Sarah
name: Shen, Sijing
Publisher: name: arXiv
Year: 2013
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We examine the pressure of the star-forming interstellar medium (ISM) of Milky-Way sized disk galaxies using fully cosmological SPH+N-body, high resolution simulations. These simulations include explicit treatment of metal-line cooling in addition to dust and self-shielding, $\mathrm{H_{2}}$ based star formation. The 4 simulated halos have masses ranging from a few times $10^{10}$ to nearly $10^{12}$ solar masses. Using a kinematic decomposition of these galaxies into present-day bulge and disk components, we find that the typical pressure of the star-forming ISM in the present-day bulge is higher than that in the present-day disk by an order of magnitude. We also find that pressure of the star-forming ISM at high redshift is on average, higher than ISM pressures at low redshift. This explains the why the bulge forms at higher pressures: the disk assembles at lower redshift, when the ISM is lower pressure and the bulge forms at high redshift, when the ISM is at higher pressure. If ISM pressure and IMF variation are tied together as suggested in studies like \cite{Conroy2012}, these results could indicate a time-dependent IMF in Milky-Way like systems, as well as a different IMF in the bulge and the disk.
description: Accepted 12/3/2013 to ApJL
Inventário de referências sobre hormonioterapia e os riscos de câncer em pessoas transgêneros: Protocolo
Creators: name: Figueiró, Mabel Fernandes
name: Yonekura, Tatiana
name: Uchimura, Liza Yurie Teruya
Publisher: name: Zenodo
Year: 2023
Subjects: Pessoas Transgêneros; Câncer; Hormonioterapia

description: Objetivo: Identificar as evidências científicas disponíveis sobre o risco de desenvolver câncer em pessoas transgêneros em tratamento com hormonioterapia. Metodologia: Será realizado um inventário de referências, a partir da realização de busca da literatura nas seguintes bases de dados eletrônicas: PubMed, Embase, Biblioteca Virtual em Saúde (BVS) Cochrane Library e Epistemonikos. As etapas de triagem pelo título e resumo serão realizadas por um revisor e conferida por outro. No caso de divergências na seleção dos estudos, estas serão resolvidas por um terceiro revisor. Os resultados serão apresentados por: autor do estudo, ano de publicação, tipo de instituição, tipo de estudo, público-alvo, tipo de hormonioterapia e tipo de câncer relatado.