cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Explosive nucleosynthesis of a metal-deficient star as the source of a distinct odd-even effect in the solar twin HIP 11915
Creators: name: Galarza, Jhon Yana
name: Meléndez, Jorge
name: Karakas, Amanda I.
name: Asplund, Martin
name: Lorenzo-Oliveira, Diego
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The abundance patterns observed in the Sun and in metal-poor stars show a clear odd-even effect. An important question is whether the odd-even effect in solar-metallicity stars is similar to the Sun, or if there are variations that can tell us about different chemical enrichment histories. In this work, we report for the first time observational evidence of a differential odd-even effect in the solar twin HIP 11915, relative to the solar odd-even abundance pattern. The spectra of this star were obtained with high resolving power (140 000) and signal-to-noise ratio ($\sim$420) using the ESPRESSO spectrograph and the VLT telescope. Thanks to the high spectral quality, we obtained extremely precise stellar parameters ($σ(T_{\rm eff})$ = 2 K, $σ(\rm{[Fe/H]})$ = 0.003 dex, and $σ(\log g)$ = 0.008 dex). We determine the chemical abundance of 20 elements ($Z\leq39$) with high precision ($\sim$0.01 dex), which shows a strong pattern of the odd-even effect even after performing Galactic Chemical Evolution corrections. The odd-even effect is reasonably well-reproduced by a core-collapse supernova of 13 $\rm{M_{\odot}}$ and metallicity Z = 0.001 diluted into a metal-poor gas of 1 $\rm{M_{\odot}}$. Our results indicate that HIP 11915 has an odd-even effect slightly different than the Sun, thus confirming a different supernova enrichment history.
description: 5 pages, 2 figures and 2 tables
Probing frequency-dependent half-wave plate systematics for CMB experiments with full-sky beam convolution simulations
Creators: name: Duivenvoorden, Adriaan J.
name: Adler, Alexandre E.
name: Billi, Matteo
name: Dachlythra, Nadia
name: Gudmundsson, Jon E.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: We study systematic effects from half-wave plates (HWPs) for cosmic microwave background (CMB) experiments using full-sky time-domain beam convolution simulations. Using an optical model for a fiducial spaceborne two-lens refractor telescope, we investigate how different HWP configurations optimized for dichroic detectors centred at 95 and 150 GHz impact the reconstruction of primordial B-mode polarization. We pay particular attention to possible biases arising from the interaction of frequency dependent HWP non-idealities with polarized Galactic dust emission and the interaction between the HWP and the instrumental beam. To produce these simulations, we have extended the capabilities of the publicly available beamconv code. To our knowledge, we produce the first time-domain simulations that include both HWP non-idealities and realistic full-sky beam convolution. Our analysis shows how certain achromatic HWP configurations produce significant systematic polarization angle offsets that vary for sky components with different frequency dependence. Our analysis also demonstrates that once we account for interactions with HWPs, realistic beam models with non-negligible cross-polarization and sidelobes will cause significant B-mode residuals that will have to be extensively modelled in some cases.
title: Towards precision gravimetry using light-pulse atom interferometry
Creators: name: Heffer, JS
Publisher: name: University of Liverpool Repository
Year: 2023

description: A light-pulse atom interferometer for inertial sensing applications such as gravimetry is being commissioned, where the prototype has a target relative precision (σ g /g) of one part per million to enable geophysics applications, which is three orders of magnitude less sensitive than commercial optical gravimeters, but with the potential to exceed these. As part of this, a rubidium-85 magneto-optical trap was upgraded using optical amplification and fibre optics to capture an atom population number of O(10 8 ) and sub-Doppler cooling techniques have been used to reach ultracold temperatures of 20 μK. Several interferometer subsystems have been developed, including extensive optical systems featuring a high-specification optical modulator and laser-induced fluorescence detection. Preliminary investigations into the coherent manipulation of atomic states have been implemented and the resonance peak of a stimulated Raman transition has been observed.
Ferromagnetic phase of spinel compound MgV$_2$O$_4$ and its spintronics properties
Creators: name: Azadani, Javad G.
name: Jiang, Wei
name: Wang, Jian-Ping
name: Low, Tony
Publisher: name: arXiv
Year: 2020
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Spinel compound, MgV$_2$O$_4$, known as a highly frustrated magnet has been extensively studied both experimentally and theoretically for its exotic quantum magnetic states. However, due to its intrinsic insulating nature in its antiferromagnetic (AFM) ground state, its realistic applications in spintronics are quite limited. Here, based on first-principles calculations, we examine the ferromagnetic (FM) phase of MgV$_2$O$_4$, which was found to host three-dimensional flat band (FB) right near the Fermi level, consequently yielding a large anomalous Hall effect (AHE, $σ\approx 670\,Ω^{-1}\cdot cm^{-1}$). Our calculations suggest that the half-metallicity feature of MgV$_2$O$_4$ is preserved even after interfacing with MgO due to the excellent lattice matching, which could be a promising spin filtering material for spintronics applications. Lastly, we explore experimental feasibility of stabilizing this FM phase through strain and doping engineering. Our study suggests that experimentally accessible amount of hole doping might induce a AFM-FM phase transition.
description: 6 pages, 4 figures
D4.6 FAIR Data Cubes - Release III
Creators: name: Mantovani, Simone
Publisher: name: Zenodo
Year: 2022
Subjects: RELIANCE
Research Objects
ROhub
RO-Crate
Data cubes
EOSC

description: RELIANCE, short for Research Lifecycle Management for Earth Science Communities and Copernicus users in EOSC, aims to realize the vision of FAIR research in EOSC by adopting a holistic research management approach based on three key and complementary technologies: i) Research objects (RO) as the overarching mechanism to manage scientific research activities; ii) data cubes as the mechanisms enabling an efficient and scalable Earth Observation data discovery and access; iii) text mining and semantic enrichment services allowing to extract machine-readable metadata from RO resources, enabling researchers to discover scientific information at scale and to structure their own research. This document describes the final release of FAIR Data Cube resources requested by RELIANCE user communities and made available within the RELIANCE project. The FAIR Data Cube resources are stored in the MEEO cloud resources. The Data Cube Metadata Model adopted for describing FAIR Data Cubes and Data Cube API are detailed in the D4.1 and D4.2, respectively.
description: This is the draft version of the deliverable not yet approved by the European Commission.
Photo-oxidation of tyrosine in a bio-engineered bacterioferritin 'reaction centre'
Creators: name: Hingorani, Kastoori
Publisher: name: Canberra, ACT : The Australian National University
Year: 2012
Subjects: bacterioferritin
photosystem II
reaction centre
tyrosine oxidation
artificial photosynthesis
protein engineering
electron transfer
ZnCe6

description: The photosynthetic reaction centre (RC) is central to conversion of solar energy into chemical energy. In this thesis, in order to introduce the redox-active cofactors similar to that of the Photosystem II RC, a non-photosynthetic protein scaffold was used as an in vitro model. The protein tasked for this purpose was the heme containing bacterioferritin (BFR) protein found in E. coli. The BFR protein naturally expresses as a homodimer based on a 4-helix bundle monomer. Desirable properties included: (i) a promiscuos di-nuclear metal binding site which provides ligands for class II metals such as Mn (ii) a hydrophobic pocket at the dimer interface which can bind a photosensitive porphyrin, in this case a chlorin (Ce6), and (iii) presence of tyrosine residues proximal to the bound cofactors, which can be utilised as efficient electron-tunnelling intermediates. The work in this thesis extends earlier work in the group by refining and improving the BFR system. Several mutants were made and an improved protein expression system was developed. For these samples experiments demonstrated ligation of weakly coupled equivalent Mn2II,II at the di-nuclear binding site of apo-BFR, and binding of the photo-active pigment ZnCe6 in hydrophobic pocket of the protein. Light-induced electron transfer from proximal tyrosine residue(s) to the photo-oxidised ZnCe6+, in the modified BFR reconsitituted with both ZnCe6 and MnII is presented. Three site-specific tyrosine mutants (Y25F, Y58F and Y45F) were made to localise the redox-active tyrosine in this engineered system. The results indicate that: (i) presence of bound MnII is necessary to observe tyrosine oxidation in all BFR variants, (ii) Y45 (within van Der Waals network of ZnCe6) is singly the most important tyrosine as the immediate electron donor to the oxidised ZnCe6+, and (iii) Y25 and Y58 are both redox-active in this system, but appear to be interchangebale. A high-resolution (~1.5 Ã…) crystal structure of the three tyrosine mutants was obtained and these structures showed there to be no mutation-induced effects on the overall 3-D structure of the protein. Minimal effects observed in the Y45F mutant are reported. The molecular design of a "second generation" of the BFR series is also presented where the symmetry of the BFR homodimer is broken to generate a BFR heterodimer to contain genetically distinct electron donor and acceptor subunits. The BFR heterodimer was made by introducing a small (20 aa) peptide linker between the two subunits. The ultimate goal will be to demonstrate light-induced directional electron flow in the BFR heterodimer.
Diagnostics of irradiated dense gas in galaxy nuclei. II. A grid of XDR and PDR models
Creators: name: Meijerink, R.
name: Spaans, M.
name: Israel, F. P.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: \abridged The nuclei of active galaxies harbor massive young stars, an accreting central black hole, or both. In order to determine the physical conditions that pertain to molecular gas close to the sources of radiation, numerical models are constructed. These models determine the thermal and chemical balance of molecular gas that is exposed to X-rays and far-ultraviolet radiation, as a function of depth. We present a grid of XDR and PDR models that span ranges in density, irradiation and column density. We find that the fine-structure line ratios of e.g. [SiII] 35mum/[CII] 158 mum are larger in XDRs than in PDRs, for a given density, column and irradiation strength. We find that the line ratios HCN/HCO+ and HNC/HCN, as well as the column density ratio CN/HCN, discriminate between PDRs and XDRs. The HCN/HCO+ 1-0 ratio is <1 (>1) for XDRs (PDRs) if the density exceeds 10^5 cm^-3 and if the column density is >10^23 cm^-2. For columns <10^ 22.5 cm^-2 the XDR HCN/HCO+ 1-0 ratio becomes larger than one, although the individual HCN 1-0 and HCO+ 1-0 line intensities are weaker. For modest densities, n=10^4-10^5 cm^-3, and strong radiation fields (>100 erg s^-1 cm^-2), HCN/HCO+ ratios can become larger in XDRs than PDRs as well. The HCN/CO 1-0 ratio is typically smaller in XDRs, and the HCN emission in XDRs is boosted with respect to CO only for columns >10^{23} cm^{-2} and densities <10^4 cm^-3. CO is typically warmer in XDRs than in PDRs, for the same total energy input. This leads to higher CO J=N+1-N/CO 1-0, N>=1, line ratios in XDRs. Lines with N>=10, like CO(16-15) and CO(10-9) observable with HIFI/Herschel, discriminate very well between XDRs and PDRs. Column density ratios indicate that CH, CH+, NO, HOC+ and HCO are good PDR/XDR discriminators.
description: 34 pages, 47 figures, accepted by A&A, a version with all figures is available at http://www.strw.leidenuniv.nl/~meijerin/grid/GridCodes_printer.pdf
Genomic structure and assessment of the retinally expressed RFamide-related peptide gene in dominant cystoid macular dystrophy
Creators: name: Schulz, H. L.
name: Stöhr, H.
name: White, K.
name: van Driel, M. A.
name: Hoyng, C. B.
name: Cremers, F.
name: Weber, Bernhard H. F.
Publisher: name: Universität Regensburg
Year: 2002
Subjects: subject: 610 Medizin

description: Purpose: Computer-assisted sampling of EST data contained within the UniGene human sequences collection is being used to establish a catalog of novel genes that are expressed exclusively or predominantly in the human retina. This provides a valuable source for candidate genes possibly involved in retinal degeneration. In this report we present the characterization of the C7orf9 gene locus encoding RFamide-related peptides (RFRPs) and its evaluation in dominant cystoid macular dystrophy (CYMD). Methods: Bioinformatics and cDNA library screening were used to isolate the full-length cDNA sequence and to determine the genomic organization of C7orf9. Expression profiling was done by RT-PCR and Northern blot analysis. C7orf9 was evaluated as a candidate gene for CYMD by DNA sequencing and Southern blot analysis in two affected individuals from an extended Dutch CYMD family. Results: The C7orf9 cDNA transcript consists of 1190 bp and is organized into 3 exons on the short arm of chromosome 7 within the critical region for CYMD. The transcript is specifically expressed in the retina but not in a large range of other human tissues. No disease-causing mutations or larger gene rearrangements were found. Conclusions: We provide the genomic organization of the RFamide-related peptide gene, C7orf9, which encodes a precursor protein for at least two small neuropeptides, referred to as NPSF (alias RFRP-1) and NPVF (alias RFRP-3) and show that it is abundantly expressed in the human retina. Results of our comprehensive mutation analysis suggests that C7orf9 is not the CYMD gene.
Extended Fast Action Minimisation method: application to SDSS-DR12 Combined Sample
Creators: name: Sarpa, E.
name: Veropalumbo, A.
name: Schimd, C.
name: Branchini, E.
name: Matarrese, S.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We present the first application of the extended Fast Action Minimization method (eFAM) to a real dataset, the SDSS-DR12 Combined Sample, to reconstruct galaxies orbits back-in-time, their two-point correlation function (2PCF) in real-space, and enhance the baryon acoustic oscillation (BAO) peak. For this purpose, we introduce a new implementation of eFAM that accounts for selection effects, survey footprint, and galaxy bias. We use the reconstructed BAO peak to measure the angular diameter distance, D_A(z)r^{fid}_s/r_s, and the Hubble parameter, H(z)r_s/r^{fid}_s, normalized to the sound horizon scale for a fiducial cosmology r^{fid}_s, at the mean redshift of the sample z=0.38, obtaining D_A(z=0.38)r^{fid}_s/r_s=1090 +/- 29 (Mpc)^{-1}, and H(z=0.38)r_s}/r^{fid}_s=83 +/- 3 (km s^{-1}Mpc^{-1}), in agreement with previous measurements on the same dataset. The validation tests, performed using 400 publicly available SDSS-DR12 mock catalogues, reveal that eFAM performs well in reconstructing the 2PCF down to separations of 25h^{-1}Mpc$, i.e. well into the non-linear regime. Besides, eFAM successfully removes the anisotropies due to redshift-space distortion at all redshifts including that of the survey, allowing us to decrease the number of free parameters in the model and fit the full-shape of the back-in-time reconstructed 2PCF well beyond the BAO peak. Recovering the real-space 2PCF, eFAM improves the precision on the estimates of the fitting parameters. When compared with the no-reconstruction case, eFAM reduces the uncertainty of the Alcock-Paczynski distortion parameters of about 40% and that on the non-linear damping scale of about 70%. These results show that eFAM can be successfully applied to existing redshift galaxy catalogues and should be considered as a reconstruction tool for next-generation surveys alternative to popular methods based on the Zel'dovich approximation.
ALMA chemical survey of disk-outflow sources in Taurus (ALMA-DOT) III: The interplay between gas and dust in the protoplanetary disk of DG Tau
Creators: name: Podio, L.
name: Garufi, A.
name: Codella, C.
name: Fedele, D.
name: Rygl, K.
name: Favre, C.
name: Bacciotti, F.
name: Bianchi, E.
name: Ceccarelli, C.
name: Mercimek, S.
name: Teague, R.
name: Testi, L.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Planets form in protoplanetary disks and inherit their chemical composition. It is therefore crucial to understand the disks molecular content. We aim to characterize the distribution and abundance of molecules in the disk of DG Tau. In the context of the ALMA chemical survey of Disk-Outflow sources in Taurus (ALMA-DOT) we analyse ALMA observations of the disk of DG Tau in H2CO 3(1,2)-2(1,1), CS 5-4, and CN 2-1 at ~0.15", i.e. ~18 au at 121 pc. H2CO and CS originate from a disk ring at the edge of the 1.3mm dust continuum, with CS probing an outer disk region with respect to H2CO (peaking at ~70 and ~60 au, respectively). CN originates from an outermost disk/envelope region peaking at ~80 au. H2CO is dominated by disk emission, while CS probes also two streams of material possibly accreting onto the disk with a peak of emission where the stream connects to the disk. The ring- and disk-height- averaged column densities are ~2.4-8.6e13 cm-2 (H2CO), ~1.7-2.5e13 cm-2 (CS), and ~1.9-4.7e13 cm-2 (CN). Unsharp masking reveals a ring of enhanced dust emission at ~40 au, i.e. just outside the CO snowline (~30 au). CS and H2CO emissions are co-spatial suggesting that they are chemically linked. The observed rings of molecular emission at the edge of the 1.3mm continuum may be due to dust opacity effects and/or continnum over-subtraction in the inner disk; as well as to increased UV penetration and/or temperature inversion at the edge of the mm-dust which would cause an enhanced gas-phase formation and desorption of these molecules. Moreover, H2CO and CS originate from outside the ring of enhanced dust emission, which also coincides with a change of the linear polarization at 0.87mm. This suggests that outside the CO snowline there could be a change of the dust properties which would reflect in the increase of the intensity (and change of polarization) of continuum, and of molecular emission.
description: 13 pages, accepted for publication on A&A
Fluctuation Theorem and Chaos
Creators: name: Gallavotti, Giovanni
Publisher: name: arXiv
Year: 2008
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The heat theorem (i.e. the second law of thermodynamics or the existence of entropy) is a manifestation of a general property of hamiltonian mechanics and of the ergodic Hypothesis. In nonequilibrium thermodynamics of stationary states the chaotic hypothesis plays a similar role: it allows a unique determination of the probability distribution (called {\rm SRB} distribution on phase space providing the time averages of the observables. It also implies an expression for a few averages concrete enough to derive consequences of symmetry properties like the fluctuation theorem or to formulate a theory of coarse graining unifying the foundations of equilibrium and of nonequilibrium.
description: Basis for the plenary talk at StatPhys23 (Genova July 2007)
Elicitation of the Questionnaire on Information Structure
Creators: name: Parker, Verdena
name: Newbold, Lindsey
Publisher: name: California Language Archive, University of California, Berkeley
Year: 2022
Subjects: subject: hup

description: Audio file VP-161011-08: Elicitation based on the Questionnaire on Information Structure (QUIS), starting with page 74, item 1. Reference: Skopeteas, Stavros et al. 2006. Questionnaire on Information Structure. Interdisciplinary Studies on Information Structure, Volume 4. Potsdam: Universitätsverlag Potsdam.
Beyond intensity modulation: new approaches to pump-probe microscopy
Creators: name: Jiang, Jun
name: Grass, David
name: Zhou, Yue
name: Warren, Warren S.
name: Fischer, Martin C.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optics (physics.optics)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Biological Physics (physics.bio-ph)
subject: FOS: Physical sciences

description: Pump-probe microscopy is an emerging nonlinear imaging technique based on high repetition rate lasers and fast intensity modulation. Here we present new methods for pump-probe microscopy that keep the beam intensity constant and instead modulate the inter-pulse time delay, the relative polarization, or the pulse length. These techniques can improve image quality for samples that have poor heat dissipation or long-lived radiative states, and can selectively address nonlinear interactions in the sample. We experimentally demonstrate this approach and point out the advantages over conventional intensity modulation.
Determination of CP and CPT violation parameters in the neutral kaon system using the Bell-Steinberger relation and data from the KLOE experiment
Creators: name: The KLOE Collaboration
name: D'Ambrosio, G.
name: Isidori, G.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We present an improved determination of the CP and CPT violation parameters Re(epsilon) and Im(delta) based on the unitarity condition (Bell-Steinberger relation) and on recent results from the KLOE experiment. We find Re(epsilon) = (159.6 \pm 1.3)10^-5 and Im(delta) = (0.4 \pm 2.1)10^-5, consistent with no CPT violation.
description: Submitted to JHEP
Elicitation of pronouns
Creators: name: Parker, Verdena
name: Newbold, Lindsey
name: Spence, Justin
Publisher: name: California Language Archive, University of California, Berkeley
Year: 2022
Subjects: subject: hup

description: Audio files VP-161011-09 and VP-161011-10: Elicitation of pronouns based on an article by Nick Evans (details of the reference are not provided).
Colpoda cavicola Kahl 1935
Creators: name: Durán-Ramírez, Carlos Alberto
name: Dias, Roberto Júnio Pedroso
name: Estrada, Rosaura Mayén-
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Chromista
Ciliophora
Oligohymenophorea
Hymenostomatida
Tetrahymenidae
Colpoda
Colpoda cavicola

description: Colpoda cavicola Kahl, 1935
Distribution. MEXICO: Biocultural Reserve Kaxil Kiuic, near Oxkutzcab (ps), (Ab).
description: Published as part of Durán-Ramírez, Carlos Alberto, Dias, Roberto Júnio Pedroso & Estrada, Rosaura Mayén-, 2020, Checklist of ciliates (Alveolata: Ciliophora) that inhabit in bromeliads from the Neotropical Region, pp. 1-36 in Zootaxa 4895 (1) on page 22, DOI: 10.11646/zootaxa.4895.1.1, http://zenodo.org/record/4321437
The Impact of Galaxy Cluster Mergers on Cosmological Parameter Estimation from Surveys of the Sunyaev-Zel'dovich Effect
Creators: name: Wik, Daniel R.
name: Sarazin, Craig L.
name: Ricker, Paul M.
name: Randall, Scott W.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Sensitive surveys of the Cosmic Microwave Background will detect thousands of galaxy clusters via the Sunyaev-Zel'dovich (SZ) effect. Two SZ observables, the central or maximum and integrated Comptonization parameters y_max and Y, relate in a simple way to the total cluster mass, which allow the construction of mass functions (MFs) that can be used to estimate cosmological parameters such as Omega_M, sigma_8, and the dark energy parameter w. However, clusters form from the mergers of smaller structures, events that can disrupt the equilibrium of intracluster gas upon which SZ-M relations rely. From a set of N-body/hydrodynamical simulations of binary cluster mergers, we calculate the evolution of Y and y_max over the course of merger events and find that both parameters are transiently "boosted," primarily during the first core passage. We then use a semi-analytic technique developed by Randall et al. (2002) to estimate the effect of merger boosts on the distribution functions YF and yF of Y and y_max, respectively, via cluster merger histories determined from extended Press-Schechter (PS) merger trees. We find that boosts do not induce an overall systematic effect on YFs, and the values of Omega_M, sigma_8, and w were returned to within 2% of values expected from the nonboosted YFs. The boosted yFs are significantly biased, however, causing Omega_M to be underestimated by 15-45%, sigma_8 to be overestimated by 10-25%, and w to be pushed to more negative values by 25-45%. We confirm that the integrated SZ effect, Y, is far more robust to mergers than y_max, as previously reported by Motl et al. (2005) and similarly found for the X-ray equivalent Y_X, and we conclude that Y is the superior choice for constraining cosmological parameters.
description: 16 pages, 6 figures, Accepted for publication in the Astrophysical Journal
Constrained Non-Linear Phase Retrieval for Single Distance X-ray Phase Contrast Tomography
Creators: name: Mohan, K. Aditya
name: Parkinson, Dilworth Y.
name: Cuadra, Jefferson A.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Image and Video Processing (eess.IV)
subject: Numerical Analysis (math.NA)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Mathematics

description: X-ray phase contrast tomography (XPCT) is widely used for 3D imaging of objects with weak contrast in X-ray absorption index but strong contrast in refractive index decrement. To reconstruct an object imaged using XPCT, phase retrieval algorithms are first used to estimate the X-ray phase projections, which is the 2D projection of the refractive index decrement, at each view. Phase retrieval is followed by refractive index decrement reconstruction from the phase projections using an algorithm such as filtered back projection (FBP). In practice, phase retrieval is most commonly solved by approximating it as a linear inverse problem. However, this linear approximation often results in artifacts and blurring when the conditions for the approximation are violated. In this paper, we formulate phase retrieval as a non-linear inverse problem, where we solve for the transmission function, which is the negative exponential of the projections, from XPCT measurements. We use a constraint to enforce proportionality between phase and absorption projections. We do not use constraints such as large Fresnel number, slowly varying phase, or Born/Rytov approximations. Our approach also does not require any regularization parameter tuning since there is no explicit sparsity enforcing regularization function. We validate the performance of our non-linear phase retrieval (NLPR) method using both simulated and real synchrotron datasets. We compare NLPR with a popular linear phase retrieval (LPR) approach and show that NLPR achieves sharper reconstructions with higher quantitative accuracy.
description: 2020 IS&T International Symposium on Electronic Imaging
Domain wall magnetoresistance in a nanopatterned La(2/3)Sr(1/3)MnO3 track
Creators: name: Arnal, T.
name: Khvalokvskii, A. V.
name: Bibes, M.
name: Lecoeur, Ph.
name: Haghiri-Gosnet, A. -M.
name: Mercey, B.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We have measured the contribution of magnetic domain walls (DWs) to the electric resistance in epitaxial manganite films patterned by electron-beam lithography into a track containing a set of notches. We find a DW resistance-area (RA) product of ~2.5 10^(-13) Ohm/m^2 at low temperature and bias, which is several orders of magnitude larger than the values reported for 3d ferromagnets. However, the current-voltage characteristics are highly linear which indicates that the DWs are not phase separated but metallic. The DWRA is found to increase upon increasing the injected current, presumably reflecting some deformation of the wall by spin-transfer. When increasing temperature, the DWRA vanishes at ~225K which is likely related to the temperature dependence of the film anisotropy.
Enhancing the HTA through Multi-Criteria Decision Analysis
Creators: name: Dowie, Jack
name: Kaltoft, Mette Kjer
Publisher: name: F1000Research
Year: 2015

description: The poster explores and illustrates the ways in which the technique of Multi-Criteria Decision Analysis (MCDA) can contribute to, and typically enhance, a Health Technology Assessment. It is shown how the four perspectives of HTA (technology, patient, organisation and economy) can be incorporated in a Multi-Criteria Decision Analysis (MCDA) framework through appropriate specification of the criteria and supporting evidence. This is best accomplished by taking a patient-focused view of the technology concerned and MCDA is therefore an ideal way to facilitate the development of a ‘Patient-centred HTA’. The discussion is related to both national and lower-level HTAs and particular attention is paid to the enhancing of the Danish hospital level 'mini HTA'.  Empirical examples developed using the Annalisa implementation of MCDA (accompanied by its add-on which enables customisation on the basis of individual or group characteristics) are provided, including clinical (medical, surgical, nursing), regulatory and population level assessments.
The impact of nebular emission on the broadband fluxes of high-redshift galaxies
Creators: name: Zackrisson, E.
name: Bergvall, N.
name: Leitet, E.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: A substantial fraction of the light emitted from young or star-forming galaxies at ultraviolet to near-infrared wavelengths comes from the ionized interstellar medium in the form of emission lines and a nebular continuum. At high redshifts, star formation rates are on average higher and stellar populations younger than in the local Universe. Both of these effects act to boost the impact of nebular emission on the overall spectrum of galaxies. Even so, the broadband fluxes and colours of high-redshift galaxies are routinely analyzed under the assumption that the light observed originates directly from stars. Here, we assess the impact of nebular emission on broadband fluxes in Johnson/Cousins BVRIJHK, Sloan Digital Sky Survey griz and Spitzer IRAC/MIPS filters as a function of observed redshift (up to z=15) for galaxies with different star formation histories. We find that nebular emission may account for a non-negligible fraction of the light received from high-redshift galaxies. The ages and masses inferred for such objects through the use of spectral evolutionary models that omit the nebular contribution are therefore likely to contain systematic errors. We argue that a careful treatment of the nebular component will be essential for the interpretation of the rest-frame ultraviolet-to-infrared properties of the first galaxies formed, like the ones expected to be detected with the James Webb Space Telescope.
description: 5 pages, 3 figures, accepted for publication in ApJL
Living microbes (Miyamotoi borrelia biofilm communities) dwell inside of Alzheimer's amyloid plaques
Creators: name: MacDonald, Alan
Publisher: name: F1000Research
Year: 2015

description: Living Borrelia microbes in biofilm communities completely fill 100% of the amyloid plaques of Alzheimer's disease.  Amyloid covers and defines the geography of each Alzheimer's plaque. According to the research of Dr. Rudolph Tanzi, PhD, of the Harvard Medical School,  antimicrobial type amyloid is deposited in Alzheimer's plaques. The marriage of Dr. Tanzi's antimicrobial role for Alzheimer's amyloid with the Fluorescence In Situ DNA Hybridization  [FISH method] (using molecular beacon type DNA probes) presents a specific amyloid target microbe population for its antimicrobial functions. Biofilms of Borrelia, existing as chronic deep brain biofilm communities, grow in size ( Alz.Dis. Plaques grow in size) over the duration of the disease, and biofilm communities are traversed by a network of water channel spaces (amyloid plaques are riddled with empty spaces or voids). Alzheimer's disease is redefined as a chronic biofilm infection of the brain, which attracts antibacterial beta 1-42 amyloid to bind to the infectomes living microbes which dwell inside of the biofilm communities. An infectious pathway to the development of Alzheimer's Disease has an enormous impact on prospects for control and for cure of Alzheimer's disease,with the prospect of eradication of this dementia, just as late syphilis dementia {general paresis of the insane } was eradicated by penicillin therapy.
Highly Confined In-plane Exciton-Polaritons in Monolayer Semiconductors
Creators: name: Epstein, Itai
name: Chaves, Andre J.
name: Rhodes, Daniel A.
name: Frank, Bettina
name: Watanabe, Kenji
name: Taniguchi, Takashi
name: Giessen, Harald
name: Hone, James C.
name: Peres, Nuno M. R.
name: Koppens, Frank H. L.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: 2D materials support unique excitations of quasi-particles that consist of a material excitation and photons called polaritons. Especially interesting are in-plane propagating polaritons which can be confined to a single monolayer and carry large momentum. In this work, we report the existence of a new type of in-plane propagating polariton, supported on monolayer transition-metal-dicalcogonide (TMD) in the visible spectrum, which has not yet been observed. This 2D in-plane exciton-polariton (2DEP) is described by the coupling of an electromagnetic light field with the collective oscillations of the excitons supported by monolayer TMDs. We expose the specific experimental conditions required for the excitation of the 2DEP and show that these can be created if the TMD is encapsulated with hexagonal-boron-nitride (hBN) and cooled to cryogenic temperatures. In addition, we compare the properties of the 2DEPs with those of surface-plasmons-polaritons (SPPs) at the same spectral range, and find that the 2DEP exhibit over two orders-of-magnitude larger wavelength confinement. Finally, we propose two configurations for the possible experimental observation of 2DEPs.
Systematic errors in cosmic microwave background polarization measurements
Creators: name: O'Dea, Daniel
name: Challinor, Anthony
name: Johnson, Bradley R.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We investigate the impact of instrumental systematic errors on the potential of cosmic microwave background polarization experiments targeting primordial B-modes. To do so, we introduce spin-weighted Muller matrix-valued fields describing the linear response of the imperfect optical system and receiver, and give a careful discussion of the behaviour of the induced systematic effects under rotation of the instrument. We give the correspondence between the matrix components and known optical and receiver imperfections, and compare the likely performance of pseudo-correlation receivers and those that modulate the polarization with a half-wave plate. The latter is shown to have the significant advantage of not coupling the total intensity into polarization for perfect optics, but potential effects like optical distortions that may be introduced by the quasi-optical wave plate warrant further investigation. A fast method for tolerancing time-invariant systematic effects is presented, which propagates errors through to power spectra and cosmological parameters. The method extends previous studies to an arbitrary scan strategy, and eliminates the need for time-consuming Monte-Carlo simulations in the early phases of instrument and survey design. We illustrate the method with both simple parametrized forms for the systematics and with beams based on physical-optics simulations. Example results are given in the context of next-generation experiments targeting tensor-to-scalar ratios r ~ 0.01.
description: 19 pages, 7 figures; Minor changes to match version accepted by MNRAS
Application of wavelet transforms to seismic data processing and inversion
Creators: name: Li, Xin-Gong
Publisher: name: University of British Columbia
Year: 2009

description: The goal of this thesis is to use wavelet transforms as tools to analyze simultaneously the time (or location) and frequency (or scale) variant characteristics of seismic data and then to apply these information to two important geophysical problems: noise filtering and traveltime inversion. In the noise filtering problem, the discrete non-orthogonal wavelet transform is used to analyze the time-variant characteristics of signal and noise. This information can be used to filter noise in the transformed domain. This approach is applied to ground roll attenuation for field seismic data according to the localized characteristics. Geophysical inverse problems are, in general, non-linear, underdetermined and ill-posed. An initial model and some prior information describing the model is needed to find the model perturbation that minimizes an objective function. Traditionally, the perturbation is assumed to be an independent Gaussian or a correlated but stationary process, an assumption which is not physically correct according to the analyses of well logs. Indeed, analysis of logs described in this thesis suggests that log data can be decomposed into (a) a fractal process, usually non-stationary, with wavelet coefficients which follow a power law, and (b) some non-fractal structures including a large scale trend and some spiky details. The inverse problem can be solved using the wavelet transform in two steps. First, I solve an overdetermined problem to invert the large scale trend, then, I solve for a model with fractal constraints. Another important application of the wavelet transform in inverse problems is to reduce the effects of the noise in the input data. Since the noise effect varies with scale, the regularization can be done accordingly. Wavelet transform constrained inversions are tested using 1-D and 2-D synthetic examples.
Distributed Structured Actor-Critic Reinforcement Learning for Universal Dialogue Management
Creators: name: Chen, Zhi
name: Chen, Lu
name: Liu, Xiaoyuan
name: Yu, Kai
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computation and Language (cs.CL)
subject: FOS: Computer and information sciences

description: The task-oriented spoken dialogue system (SDS) aims to assist a human user in accomplishing a specific task (e.g., hotel booking). The dialogue management is a core part of SDS. There are two main missions in dialogue management: dialogue belief state tracking (summarising conversation history) and dialogue decision-making (deciding how to reply to the user). In this work, we only focus on devising a policy that chooses which dialogue action to respond to the user. The sequential system decision-making process can be abstracted into a partially observable Markov decision process (POMDP). Under this framework, reinforcement learning approaches can be used for automated policy optimization. In the past few years, there are many deep reinforcement learning (DRL) algorithms, which use neural networks (NN) as function approximators, investigated for dialogue policy.
description: 12 pages, 7 figures
LION :Laser Interferometer On the mooN
Creators: name: Amaro-Seoane, Pau
name: Bischof, Lea
name: Carter, Jonathan J.
name: Hartig, Marie-Sophie
name: Wilken, Dennis
Publisher: name: arXiv
Year: 2020
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Gravitational wave astronomy has now left its infancy and has become an important tool for probing the most violent phenomena in our universe. The LIGO/Virgo-KAGRA collaboration operates ground based detectors which cover the frequency band from 10 Hz to the kHz regime, meanwhile the pulsar timing array and the soon to launch LISA mission will cover frequencies below 0.1 Hz, leaving a gap in detectable gravitational wave frequencies. Here we show how a Laser Interferometer On the mooN (LION) gravitational wave detector would be sensitive to frequencies from sub Hz to kHz. We find that the sensitivity curve is such that LION can measure compact binaries with masses between 10 and 100M at cosmological distances, with redshifts as high as z= 100 and beyond, depending on the spin and the mass ratio of the binaries. LION can detect binaries of compact objects with higher-masses, with very large signal-to-noise ratios, help us tounderstand how supermassive black holes got their colossal masses on the cosmological landscape, and it can observe in detail intermediate-mass ratio inspirals at distances as large as at least 100 Gpc. Compact binaries that never reach the LIGO/Virgo sensitivity band can spend significantamounts of time in the LION band, while sources present in the LISA band can be picked up by the detector and observed until their final merger. Since LION covers the deci-Hertz regime with such large signal-to-noise ratios, it truly achieves the dream of multi messenger astronomy
description: Submitted to Journal, Open for comments
Letter from James Goldie to J.E. McAllister, June 10, 1928
Creators: name: Goldie, James
Publisher: name: The University of British Columbia
Year: 2017

description: Letter to J.E. McAllister from James Goldie, dated June 10, 1928, regarding evaluation of the finances from the 1926 crop year and a copy of the statement of current assets and liabilities.
Analytical details and instrumentation parameters. Tectonic significance of a supra-ophiolitic sedimentary cover succession, Unst, Shetland, Scottish Caledonides: insights from the U–Pb–Hf detrital zircon record
Creators: name: K. Papapavlou
name: R.A. Strachan
name: C.D. Storey
name: D. Bullen
Publisher: name: Geological Society of London
Year: 2021
Subjects: subject: Geology
subject: FOS: Earth and related environmental sciences

description: Analytical details and instrumentation parameters (U–Pb and Lu–Hf isotopic analysis)
The Intrinsic Fraction of Broad Absorption Line Quasars
Creators: name: Knigge, Christian
name: Scaringi, Simone
name: Goad, Michael R.
name: Cottis, Christopher E.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We carefully reconsider the problem of classifying broad absorption line quasars (BALQSOs) and derive a new, unbiased estimate of the intrinsic BALQSO fraction from the SDSS DR3 QSO catalogue. We first show that the distribution of objects selected by the so-called ``absorption index'' (AI) is clearly bimodal in log(AI), with only one mode corresponding to definite BALQSOs. The surprisingly high BALQSO fractions that have recently been inferred from AI-based samples are therefore likely to be overestimated. We then present two new approaches to the classification problem that are designed to be more robust than the AI, but also more complete than the traditional ``balnicity index'' (BI). Both approaches yield observed BALQSO fractions around 13.5 per cent, while a conservative third approach suggests an upper limit of 18.3 per cent. Finally, we discuss the selection biases that affect our observed BALQSO fraction. After correcting for these biases, we arrive at our final estimate of the intrinsic BALQSO fraction. This is f_BALQSO = 0.17 +/- 0.01 (stat) +/- 0.03 (sys), with an upper limit of f_BALQSO = 0.23. We conclude by pointing out that the bimodality of the log(AI) distribution may be evidence that the BAL-forming region has clearly delineated physical boundaries.
description: 12 pages, 7 figures; accepted for publication in MNRAS; new version corrects minor typos and adds/updates some references
SPHRAY: A Smoothed Particle Hydrodynamics Ray Tracer for Radiative Transfer
Creators: name: Altay, Gabriel
name: Croft, Rupert A. C.
name: Pelupessy, Inti
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We introduce SPHRAY, a Smoothed Particle Hydrodynamics (SPH) ray tracer designed to solve the 3D, time dependent, radiative transfer (RT) equations for arbitrary density fields. The SPH nature of SPHRAY makes the incorporation of separate hydrodynamics and gravity solvers very natural. SPHRAY relies on a Monte Carlo (MC) ray tracing scheme that does not interpolate the SPH particles onto a grid but instead integrates directly through the SPH kernels. Given initial conditions and a description of the sources of ionizing radiation, the code will calculate the non-equilibrium ionization state (HI, HII, HeI, HeII, HeIII, e) and temperature (internal energy/entropy) of each SPH particle. The sources of radiation can include point like objects, diffuse recombination radiation, and a background field from outside the computational volume. The MC ray tracing implementation allows for the quick introduction of new physics and is parallelization friendly. A quick Axis Aligned Bounding Box (AABB) test taken from computer graphics applications allows for the acceleration of the raytracing component. We present the algorithms used in SPHRAY and verify the code by performing all the test problems detailed in the recent Radiative Transfer Comparison Project of Iliev et. al. The Fortran 90 source code for SPHRAY and example SPH density fields are made available on a companion website (www.sphray.org).
description: 17 pages, 16 figures, submitted to MNRAS, comments welcome. source code, high res. figures and examples can be found at http://www.sphray.org
Properties of grain boundaries in high-Tc superconductors -- notes on a recent presentation --
Creators: name: Mannhart, J.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The purpose of this article is to discuss a view concerning key datasets of the properties of grain boundaries in high-Tc superconductors that was recently expressed in Ref. 1. The reference also criticizes our research. Using examples I disprove this criticism.
description: Physica C, in press
The Automated Data Extraction, Processing, and Tracking System for CHARIS
Creators: name: Tobin, Taylor L.
name: Chilcote, Jeffery
name: Brandt, Timothy
name: Currie, Thayne
name: Groff, Tyler
name: Lozi, Julien
name: Guyon, Olivier
Publisher: name: arXiv
Year: 2020
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: CHARIS is an IFS designed for imaging and spectroscopy of disks and sub-stellar companions. To improve ease of use and efficiency of science production, we present progress on a fully-automated backend for CHARIS. This Automated Data Extraction, Processing, and Tracking System (ADEPTS) will log data files from CHARIS in a searchable database and perform all calibration and data extraction, yielding science-grade data cubes. The extracted data will also be run through a preset array of post-processing routines. With significant parallelization of data processing, ADEPTS will dramatically reduce the time between data acquisition and the availability of science-grade data products.