cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Novel nonadride, heptadride and maleic acid metabolites from the byssochlamic acid producer Byssochlamys fulva IMI 40021 – an insight into the biosynthesis of maleidrides
Creators: name: Cox, Russell J.
name: Szwalbe, Agnieszka J.
name: Williams, Katherine
name: O'Flynn, Daniel E.
name: Bailey, Andrew M.
name: Mulholland, Nicholas P.
name: Vincent, Jason L.
name: Willis, Christine L.
name: Simpson, Thomas J.
Publisher: name: Cambridge : Royal Society of Chemistry
Year: 2015
Subjects: subject: Byssochlamys fulva
subject: Pilz
subject: Byssochlamys fulva
subject: Dewey Decimal Classification::500 | Naturwissenschaften::540 | Chemie

description: The filamentous fungus Byssochlamys fulva strain IMI 40021 produces (+)-byssochlamic acid 1, its novel dihydroanalogue 2 and four related secondarymetabolites. Agnestadrides A, 17 and B, 18 constitute a novel class of seven-membered ring, maleic anhydride-containing (hence termed heptadride) natural products. The putative maleic anhydride precursor 5 for both nonadride and heptadride biosynthesis was isolated as a fermentation product for the first time and its structure confirmed by synthesis. Acid 5 undergoes facile decarboxylation to anhydride 6. The generic term maleidrides is proposed to encompass biosynthetically-related compounds containing maleic anhydride moieties fused to an alicyclic ring, varying in size and substituents.
A Spatially Resolved Vertical Temperature Gradient in the HD 163296 Disk
Creators: name: Rosenfeld, Katherine A.
name: Andrews, Sean M.
name: Hughes, A. Meredith
name: Wilner, David J.
name: Qi, Chunhua
Publisher: name: arXiv
Year: 2013
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We analyze sensitive, sub-arcsecond resolution ALMA Science Verification observations of CO emission lines in the protoplanetary disk hosted by the young, isolated Ae star HD 163296. The observed spatial morphology of the 12CO J=3-2 emission line is asymmetric across the major axis of the disk; the 12CO J=2-1 line features a much less pronounced, but similar, asymmetry. The J=2-1 emission from 12CO and its main isotopologues have no resolved spatial asymmetry. We associate this behavior as the direct signature of a vertical temperature gradient and layered molecular structure in the disk. This is demonstrated using both toy models and more sophisticated calculations assuming non-local thermodynamic equilibrium (non LTE) conditions. A model disk structure is developed to reproduce both the distinctive spatial morphology of the 12CO J=3-2 line as well as the J=2-1 emission from the CO isotopologues assuming relative abundances consistent with the interstellar medium. This model disk structure has tau=1 emitting surfaces for the 12CO emission lines that make an angle of about 15 degrees with respect to the disk midplane. Furthermore, we show that the spatial and spectral sensitivity of these data can distinguish between models that have sub-Keplerian gas velocities due to the vertical extent of the disk and its associated radial pressure gradient (a fractional difference in the bulk gas velocity field of approximately greater than 5%).
description: 31 pages, 13 figures, accepted for publication in ApJ
Rapid Design of Top-Performing Metal-Organic Frameworks with Qualitative Representations of Building Blocks
Creators: name: Comlek, Yigitcan
name: Pham, Thang Duc
name: Snurr, Randall
name: Chen, Wei
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Machine Learning (cs.LG)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Data-driven materials design often encounters challenges where systems require or possess qualitative (categorical) information. Metal-organic frameworks (MOFs) are an example of such material systems. The representation of MOFs through different building blocks makes it a challenge for designers to incorporate qualitative information into design optimization. Furthermore, the large number of potential building blocks leads to a combinatorial challenge, with millions of possible MOFs that could be explored through time consuming physics-based approaches. In this work, we integrated Latent Variable Gaussian Process (LVGP) and Multi-Objective Batch-Bayesian Optimization (MOBBO) to identify top-performing MOFs adaptively, autonomously, and efficiently without any human intervention. Our approach provides three main advantages: (i) no specific physical descriptors are required and only building blocks that construct the MOFs are used in global optimization through qualitative representations, (ii) the method is application and property independent, and (iii) the latent variable approach provides an interpretable model of qualitative building blocks with physical justification. To demonstrate the effectiveness of our method, we considered a design space with more than 47,000 MOF candidates. By searching only ~1% of the design space, LVGP-MOBBO was able to identify all MOFs on the Pareto front and more than 97% of the 50 top-performing designs for the CO$_2$ working capacity and CO$_2$/N$_2$ selectivity properties. Finally, we compared our approach with the Random Forest algorithm and demonstrated its efficiency, interpretability, and robustness.
description: 35 pages total. First 29 pages belong to the main manuscript and the remaining 6 six are for the supplementary information, 13 figures total. 9 figures are on the main manuscript and 4 figures are in the supplementary information. 1 table in the supplementary information
Three dimensional charged black holes in Gauss-Bonnet gravity
Creators: name: Jusufi, Kimet
name: Jamil, Mubasher
name: Sheykhi, Ahmad
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Physics (physics.gen-ph)
subject: FOS: Physical sciences

description: By using the zero-point length effect, we construct a new class of charged black hole solutions in the framework of three dimensional Gauss-Bonnet (GB) gravity with Maxwell electrodynamics. The gravitational and electromagnetic potentials as well as the spacetime curvature are finite and regular everywhere, however, the computation of scalar curvature invariants suggest the presence of a singularity at the origin. We also explore thermodynamics of the obtained solutions and reveal that the entropy of the black hole decreases due to the stringy effects. The thermodynamic and conserved quantities are computed and also the validity of the first law of thermodynamics on the black hole horizon is verified. Finally, the spinning black hole solution is also reported.
description: Accepted for publication in EPJC
O-Methylation steps during strobilurin and bolineol biosynthesis
Creators: name: Lebe, Karen E.
name: Cox, Russell J.
Publisher: name: London : RSC
Year: 2019
Subjects: subject: Strobilurins
subject: O-MeT
subject: gene cluster
subject: Dewey Decimal Classification::500 | Naturwissenschaften::540 | Chemie

description: Strobilurins are potent antifungal polyketides produced by basidiomycete fungi. Two genes encoding O-methyltransferases (O-MeT) are present in the biosynthetic gene cluster of strobilurin A 1. In previous studies, the two O-MeT enzymes Str2 and Str3 were found to catalyse the final steps of the biosynthesis of 1. Here, we show by in vivo expression experiments, that O-methylation during strobilurin biosynthesis is regiospecific. O-MeT Str2 acts first and selectively catalyses the methylation of the carboxyl group of strobilurin and bolineol precursors. Str3 catalyses the subsequent methyl transfer to the enol group to form strobilurin A 1, but cannot methylate bolineol 4. Toxicity tests showed increasing antifungal activity of intermediates through the pathway and that bolineol 4 shows antifungal activity against A. oryzae NSAR1 with an MIC of 0.1 mg ml−1.
Monopole harmonics on $\mathbb{CP}^{n-1}$
Creators: name: Bykov, Dmitri
name: Smilga, Andrei
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We find the spectra and eigenfunctions of both ordinary and supersymmetric quantum-mechanical models describing the motion of a charged particle over the $\mathbb{CP}^{n-1}$ manifold in the presence of a background monopole-like gauge field. The states form degenerate $SU(n)$ multiplets and their wave functions acquire a very simple form being expressed via homogeneous coordinates. Their relationship to multidimensional orthogonal polynomials of a special kind is discussed. By the well-known isomorphism between the twisted Dolbeault and Dirac complexes, our construction also gives the eigenfunctions and eigenvalues of the Dirac operator on complex projective spaces in a monopole background.
description: 42 pages, 3 figures, v2: minor corrections, references added
Flat Bands and High Chern Numbers in Twisted Multilayer Graphene
Creators: name: Yang, Mengxuan
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mathematical Physics (math-ph)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Spectral Theory (math.SP)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: Motivated by recent Physical Review Letters of Wang-Liu and Ledwith-Vishwanath-Khalaf, we study Tarnopolsky-Kruchkov-Vishwanath chiral model of two sheets of $n$-layer Bernal stacked graphene twisted by a small angle using the framework developed by Becker-Embree-Wittsten-Zworski. We show that magic angles of this model are exactly the same as magic angles of chiral twisted bilayer graphene with multiplicity. For small inter-layer tunneling potentials, we compute the band separation at Dirac points as we turning on the tunneling parameter. Flat band eigenfunctions are also constructed using a new theta function argument and this yields a complex line bundle with the Chern number $-n$.
description: 25 pages, 4 figures, comments are welcome
Knockout Mouse
Creators: name: Brady, Marcia
Publisher: name: Zenodo
Year: 2025

description: CRISPR/Cas9 PlatformCB is a global leading biotechnology company specializing in gene editing and has extensive experience and expertise in embryology (e.g. cryopreservation, microinjection), genetic testing and breeding. Using the latest CRISPR/Cas9 gene editing technology, our scientists have successfully achieved highly efficient CRISPR/Cas9 gene editing (>98%) in a variety of animals (including mouse, rat, rabbit, zebrafish, drosophila, etc.). Based on our platform, we are able to provide you with accurate gene knockout mouse models. All mice have been verified at genomic levels by PCR and sequencing using PCR primers strategically designed around the target site or inserted fragments.
Catalytic Modification of Flammable Atmosphere in Aircraft Fuel Tanks
Creators: name: Choi, Inki
Publisher: name: California Institute of Technology
Year: 2010
Subjects: Catalytic combustion
Aeronautics

description: A facility for investigating catalytic combustion and measurement of fuel molecule concentration was built to examine catalyst candidates for inerting systems in aircraft. The facility consists of fuel and oxygen supplies, a catalytic-bed reactor, heating system, and laser-based diagnostics. Two supplementary systems consisting of a calibration test cell and a nitrogen-purged glove box were also constructed. The catalyst under investigation was platinum, and it was mixed with silica particles to increase the surface area available to react. The catalyst/silica mixture was placed in a narrow channel section of the reactor and supported from both sides by glass wool. The fuels investigated were n-octane and n-nonane because their vapor pressure is sufficiently high to create ammable gaseous mixtures with atmospheric air at room temperature. Calibration experiments were performed to determine the absorption cross-section of the two fuels as a function of temperature. The cross-section values were then used to determine the fuel concentration before the flow entered the reactor and after exposure to the heated catalyst. An initial set of experiments was performed with the catalytic-bed reactor at two temperatures, 255 and 500°C, to investigate pyrolysis and oxidation of the fuel. The presence of the catalyst increased the degree of pyrolysis and oxidation at both temperatures. The results show that catalytic modification of ammable atmospheres may yield a viable alternative for inerting aircraft fuel tanks. However, further tests are required to produce oxidation at sufficiently low temperature to comply with aircraft safety regulations.
On Chip Protein Pre-Concentration for Enhancing the Sensitivity of Porous Silicon Biosensors
Creators: name: Arshavsky-Graham, Sofia
name: Massad-Ivanir, Naama
name: Paratore, Federico
name: Scheper, Thomas
name: Bercovici, Moran
name: Segal, Ester
Publisher: name: Washington D.C. : American Chemical Society
Year: 2017
Subjects: subject: aptamer
subject: isotachophoresis
subject: label-free
subject: optical biosensor
subject: porous silicon
subject: Dewey Decimal Classification::500 | Naturwissenschaften::540 | Chemie

description: Porous silicon (PSi) nanomaterials have been widely studied as label-free optical biosensors for protein detection. However, these biosensors’ performance, specifically in terms of their sensitivity (which is typically in the micromolar range), is insufficient for many applications. Herein, we present a proof-of-concept application of the electrokinetic isotachophoresis (ITP) technique for real-time preconcentration of a target protein on a PSi biosensor. With ITP, a highly concentrated target zone is delivered to the sensing area, where the protein target is captured by immobilized aptamers. The detection of the binding events is conducted in a label-free manner by reflective interferometric Fourier transformation spectroscopy (RIFTS). Up to 1000-fold enhancement in local concentration of the protein target and the biosensor’s sensitivity are achieved, with a measured limit of detection of 7.5 nM. Furthermore, the assay is successfully performed in complex media, such as bacteria lysate samples, while the selectivity of the biosensor is retained. The presented assay could be further utilized for other protein targets, and to promote the development of clinically useful PSi biosensors.
Categorical resolutions of irrational singularities
Creators: name: Kuznetsov, Alexander
name: Lunts, Valery A.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics

description: We show that the derived category of any singularity over a field of characteristic 0 can be embedded fully and faithfully into a smooth triangulated category which has a semiorthogonal decomposition with components equivalent to derived categories of smooth varieties. This provides a categorical resolution of the singularity.
description: 71 pages
Exploring Clozapine Treatment in Autism Spectrum Disorder and Associated Psychiatric Symptoms: A Scoping Review
Creators: name: Bezerra, Olivia Sorato
name: Graeff-Martins, Ana Soledade
name: Rohde, Luis
name: Da Rosa, André Luiz Schuh Teixeira
Publisher: name: Open Science Framework
Year: 2023
Subjects: subject: Mental Disorders
subject: Medicine and Health Sciences
subject: Psychiatric and Mental Health
subject: Mental and Social Health
subject: Psychiatry and Psychology
subject: Behavioral Disciplines and Activities
subject: Therapy
subject: Comorbidities
subject: Scoping Review
subject: Safety
subject: Pharmacology
subject: Tolerability
subject: Review
subject: Treatment
subject: Behavioural Problems
subject: Clozapine
subject: Outcomes
subject: Autism Spectrum Disorder

description: This scoping review endeavors to delineate the extent and nature of research evidences on the use of Clozapine in treating autism spectrum disorder patients and their concurrent psychiatric symptoms.
Securing Verified IO Programs Against Unverified Code in F*
Creators: name: Andrici, Cezar-Constantin
name: Ciobaca, Stefan
name: Hritcu, Catalin
name: Martínez, Guido
name: Rivas, Exequiel
name: Tanter, Éric
name: Winterhalter, Théo
Publisher: name: arXiv
Year: 2023
Subjects: subject: Programming Languages (cs.PL)
subject: FOS: Computer and information sciences

description: We introduce SCIO*, a formally secure compilation framework for statically verified partial programs performing input-output (IO). The source language is an F* subset in which a verified program interacts with its IO-performing context via a higher-order interface that includes refinement types as well as pre- and post-conditions about past IO events. The target language is a smaller F* subset in which the compiled program is linked with an adversarial context that has an interface without refinement types, pre-conditions, or concrete post-conditions. To bridge this interface gap and make compilation and linking secure we propose a formally verified combination of higher-order contracts and reference monitoring for recording and controlling IO operations. Compilation uses contracts to convert the logical assumptions the program makes about the context into dynamic checks on each context-program boundary crossing. These boundary checks can depend on information about past IO events stored in the state of the monitor. But these checks cannot stop the adversarial target context before it performs dangerous IO operations. Therefore linking in SCIO* additionally forces the context to perform all IO actions via a secure IO library, which uses reference monitoring to dynamically enforce an access control policy before each IO operation. We prove in F* that SCIO* soundly enforces a global trace property for the compiled verified program linked with the untrusted context. Moreover, we prove in F* that SCIO* satisfies by construction Robust Relational Hyperproperty Preservation, a very strong secure compilation criterion. Finally, we illustrate SCIO* at work on a simple web server example.
description: POPL'24 camera-ready version
Calibrating stellar velocity dispersions based on spatially-resolved h-band spectra for improving the m-sigma relation
Creators: name: Kang, Wol-Rang
name: Woo, Jong-Hak
name: Schulze, Andreas
name: Riechers, Dominik A.
name: Kim, Sang Chul
name: Park, Daeseong
name: Smolcic, Vernesa
Publisher: name: arXiv
Year: 2013
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: To calibrate stellar velocity dispersion measurements from optical and near-IR stellar lines, and to improve the black hole mass (MBH)- stellar velocity dispersion (sigma) relation, we measure stellar velocity dispersions based on high quality H-band spectra for a sample of 31 nearby galaxies, for which dynamical MBH is available in the literature. By comparing velocity dispersions measured from stellar lines in the H-band with those measured from optical stellar lines, we find no significant difference, suggesting that optical and near-IR stellar lines represent the same kinematics and that dust effect is negligible for early-type galaxies. Based on the spatially-resolved rotation and velocity dispersion measurements along the major axis of each galaxy, we find that a rotating stellar disk is present for 80% of galaxies in the sample. For galaxies with a rotation component, velocity dispersions measured from a single aperture spectrum can vary by up to ~20%, depending on the size of the adopted extraction aperture. To correct for the rotational broadening, we derive luminosity-weighted velocity dispersion within the effective radius of each galaxy, providing uniformly measured velocity dispersions to improve the MBH-sigma relation.
description: To be published in ApJ, 12 pages, 9 figures
Negative results - the missing piece of scientific publishing
Creators: name: Popp, Andrea
name: Van Emmerik, Tim
name: Solcerova, Anna
name: Müller, Hannes
name: Hut, Rolf
Publisher: name: München : European Geosciences Union
Year: 2018
Subjects: subject: Dewey Decimal Classification::500 | Naturwissenschaften::550 | Geowissenschaften

description: The current ‘publish or perish’ culture of our scientific system leads to a publication bias towards positive results (Curry, 2015). However, experimental failure in geosciences is the norm. Paradoxically, we typically do not share negative findings — defined as experiments giving results that do not confirm an accepted hypothesis or previous results, despite sound and careful experimental design, planning and execution — not even in informal settings. In the past, many great philosophers, including Popper (1963) and Chalmers (1973), have emphasized that science can only advance by learning from mistakes. Moreover, recent literature in various fields state the many benefits and values of publishing negative results and call upon the scientific community to nurture their dissemination (e.g., Andréassian, et al., 2010; Schooler, 2011; Matosin et al., 2014; Granqvist, 2015; Boorman, et al., 2015; PLOS collections; 2015, 2017; Nature Editorial, 2017). However, despite the various calls to report negative results, they are still a missing piece in many fields of our current publication system, including the field of hydrological research. We believe that the reason for that is a lack of incentive. Currently, reporting on negative results is neither encouraged nor rewarded. In our presentation we aim to stimulate a discussion on cultural barriers to change the way in which the scientific community including individual researchers, scientific societies, funding agencies and publishers in the field of hydrology value negative results. Moreover, we propose ways forward on how to encourage our scientific community to promote and acknowledge the concept of reporting on negative results more actively which will ultimately advance science.
Low Temperature Catalytic Ethanol Conversion Over Ceria-Supported Platinum, Rhodium, and Tin-Based Nanoparticle Systems
Creators: name: Mahmoud, Eugene Leo Draine
Publisher: name: California Institute of Technology
Year: 2010
Subjects: subject: catalyst
subject: ceria
subject: nanoparticle
subject: Mechanical Engineering
subject: FOS: Mechanical engineering
subject: ethanol conversion
subject: steam reforming
subject: low-temperature

description: Due to the feasibility of ethanol production in the United States, ethanol has become more attractive as a fuel source and a possible energy carrier within the hydrogen economy.  Ethanol can be stored easily in liquid form, and can be internally pre-formed prior to usage in low temperature (200C – 400C) solid acid and polymer electrolyte membrane fuel cells.  However, complete electrochemical oxidation of ethanol remains a challenge.  Prior research of ethanol reforming at high temperatures (> 400C) has identified several metallic and oxide-based catalyst systems that improve ethanol conversion, hydrogen production, and catalyst stability.  In this study, ceria-supported platinum, rhodium, and tin-based nanoparticle catalyst systems will be developed and analyzed in their performance as low-temperature ethanol reforming catalysts for fuel cell applications.

Metallic nanoparticle alloys were synthesized with ceria supports to produce the catalyst systems studied.  Gas phase byproducts of catalytic ethanol reforming were analyzed for temperature-dependent trends and chemical reaction kinetic parameters.  Results of catalytic data indicate that catalyst composition plays a significant role in low-temperature ethanol conversion.  Analysis of byproduct yields demonstrate how ethanol steam reforming over bimetallic catalyst systems (platinum-tin and rhodium-tin) results in higher hydrogen selectivity than was yielded over single-metal catalysts.  Additionally, oxidative steam reforming results reveal a correlation between catalyst composition, byproduct yield, and ethanol conversion.  By analyzing the role of temperature and reactant composition on byproduct yields from ethanol reforming, this study also proposes how these parameters may contribute to optimal catalytic ethanol reforming.
Kittel law and domain formation mechanism in PbTiO$_3$/SrTiO$_3$ superlattices
Creators: name: Gómez-Ortiz, Fernando
name: Aramberri, Hugo
name: López, Juan M.
name: García-Fernández, Pablo
name: Íñiguez, Jorge
name: Junquera, Javier
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We report second-principles simulations on the structural and energetic properties of domains in (PbTiO$_{3}$)$_{n}$/(SrTiO$_{3}$)$_{n}$ superlattices. For the explored layer thickness ($n$ ranging between 8 and 16 unit cells) and lateral sizes of the domains, the most stable configuration corresponds to polar domains separated by a sequence of counter-rotating vortices (clockwise/counterclockwise) perpendicular to the stacking direction and acting as domain walls. The balance between the domain wall energy and the electrostatic energy yields to an optimal domain period $ω$ that is proportional to the square-root of the thickness of the PbTiO$_{3}$ layer, following the Kittel law. For a given lateral size of the simulation box, suboptimal domain structures (with a width larger than the one predicted by the Kittel law) can be obtained in a metastable form. However, at finite temperature, molecular dynamics simulations show the spontaneous change of periodicity, which implies the formation of new domains whose generation is initiated by the nucleation of vortices and antivortices at the interface between the SrTiO$_{3}$ and the PbTiO$_{3}$ layers. The vortices progressively elongate and eventually annihilate with the antivortices yielding the formation of new domains to comply the Kittel law via a topological phase transition.
description: 7 pages, 6 Figures
Not enough high-resolution rainfall data? Generate it!
Creators: name: Müller, Hannes
name: Haberlandt, Uwe
Publisher: name: München : European Geosciences Union
Year: 2015
Subjects: subject: Dewey Decimal Classification::500 | Naturwissenschaften::550 | Geowissenschaften

description: For many hydrological applications rainfall time series with a high temporal resolution are crucial, e.g. for rainfall-runoff-modeling, urban hydrology or erosion processes. Observed time series of this kind are very short in most cases, so they cannot be used. However, information from these time series can be used for the generation of time series with long durations and high resolutions. Among an overview of different rainfall generators a special focus will be given to cascade models. With these models long time series of non-recording stations (daily measurements) can be disaggregated to the resolution of interest.
Certifying the absence of spurious local minima at infinity
Creators: name: Josz, Cédric
name: Li, Xiaopeng
Publisher: name: arXiv
Year: 2023
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: When searching for global optima of nonconvex unconstrained optimization problems, it is desirable that every local minimum be a global minimum. This property of having no spurious local minima is true in various problems of interest nowadays, including principal component analysis, matrix sensing, and linear neural networks. However, since these problems are non-coercive, they may yet have spurious local minima at infinity. The classical tools used to analyze the optimization landscape, namely the gradient and the Hessian, are incapable of detecting spurious local minima at infinity. In this paper, we identify conditions that certify the absence of spurious local minima at infinity, one of which is having bounded subgradient trajectories. We check that they hold in several applications of interest.
description: 31 pages, 4 figures
On Adequate Comparison of Antenna Phase Center Variations
Creators: name: Schön, Steffen
name: Kersten, Tobias
Publisher: name: Washington D.C. : American Geophysical Union
Year: 2013
Subjects: subject: GNSS
subject: GPS/GNSS antennas
subject: Geodesy
subject: GPS/GNSS receiver
subject: GPS/GNSS-Antennen
subject: Geodäsie
subject: GPS/GNSS-Empfänger
subject: Dewey Decimal Classification::500 | Naturwissenschaften::550 | Geowissenschaften
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: One important part for ensuring the high quality of the International GNSS Service's (IGS) products is the collection and publication of receiver - and satellite antenna phase center variations (PCV). The PCV are crucial for global and regional networks, since they introduce a global scale factor of up to 16ppb or changes in the height component with an amount of up to 10cm, respectively. Furthermore, antenna phase center variations are also important for precise orbit determination, navigation and positioning of mobile platforms, like e.g. the GOCE and GRACE gravity missions, or for the accurate Precise Point Positioning (PPP) processing. Using the EUREF Permanent Network (EPN), Baire et al. (2012) showed that individual PCV values have a significant impact on the geodetic positioning. The statements are further supported by studies of Steigenberger et al. (2013) where the impact of PCV for local-ties are analysed. Currently, there are five calibration institutions including the Institut für Erdmessung (IfE) contributing to the IGS PCV file. Different approaches like field calibrations and anechoic chamber measurements are in use. Additionally, the computation and parameterization of the PCV are completely different within the methods. Therefore, every new approach has to pass a benchmark test in order to ensure that variations of PCV values of an identical antenna obtained from different methods are as consistent as possible. Since the number of approaches to obtain these PCV values rises with the number of calibration institutions, there is the necessity for an adequate comparison concept, taking into account not only the numerical values but also stochastic information and computational issues of the determined PCVs. This is of special importance, since the majority of calibrated receiver antennas published by the IGS origin from absolute field calibrations based on the Hannover Concept, Wübbena et al. (2000). In this contribution, a concept for the adequate comparison as well as combination of PCV values will be presented. Since PCV corrections have to be applied in PPP Processing, the effect on the coordinate estimates have to be studied in detail to verify the consistent PCV modeling during the PPP processing and to quantify the impact on the coordinate domain also. Furthermore, due to the high correlation between station height, troposphere and receiver clock estimates, the impact on all estimated parameters has to be quantified. Since PPP is also frequently used for precise frequency comparison, the effect of PCV is of special interest in this field, too.
Reconnection at 3D Magnetic Null Points: Effect of Current Sheet Asymmetry
Creators: name: Wyper, Peter F
name: Jain, Rekha
Publisher: name: arXiv
Year: 2013
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: Asymmetric current sheets are likely to be prevalent in both astrophysical and laboratory plasmas with complex three dimensional (3D) magnetic topologies. This work presents kinematic analytical models for spine and fan reconnection at a symmetric 3D null with asymmetric current sheets. Asymmetric fan reconnection is characterized by an asymmetric reconnection of flux past each spine line and a bulk flow of plasma across the null point. In contrast, asymmetric spine reconnection is inherently equal and opposite in how flux is reconnected across the fan plane. The higher modes of spine reconnection also include localized wedges of vortical flux transport in each half of the fan. In this situation, two definitions for reconnection rate become appropriate: a local reconnection rate quantifying how much flux is genuinely reconnected across the fan plane and a global rate associated with the net flux driven across each semi-plane. Through a scaling analysis it is shown that when the ohmic dissipation in the layer is assumed to be constant, the increase in the local rate bleeds from the global rate as the sheet deformation is increased. Both models suggest that asymmetry in the current sheet dimensions will have a profound effect on the reconnection rate and manner of flux transport in reconnection involving 3D nulls.
description: 12 pages, 11 figures
Entanglement dynamics with string measurement operators
Creators: name: Piccitto, Giulia
name: Russomanno, Angelo
name: Rossini, Davide
Publisher: name: arXiv
Year: 2023
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We explain how to apply a Gaussian-preserving operator to a fermionic Gaussian state. We use this method to study the evolution of the entanglement entropy of an Ising spin chain following a Lindblad dynamics with string measurement operators, focusing on the quantum-jump unraveling of such Lindbladian. We find that the asymptotic entanglement entropy obeys an area law for finite-range string operators and a volume law for ranges of the string which scale with the system size. The same behavior is observed for the measurement-only dynamics, suggesting that measurements can play a leading role in this context.
description: 27 pages, 4 figures
title: Differences in Relationship and Sexual Satisfaction and Social Support Between Only Lesbian, Mostly Lesbian, and Bisexual Women
Creators: name: Turner, Meredith I.
name: Sandoval, Cassidy M.
name: Dawson, Charlotte A.
name: Heron, Kristin E.
Publisher: name: Old Dominion University Libraries
Year: 2023

description: Research suggests relationship and sexual satisfaction and social support are correlated with components of well-being such as anxiety, depression, and physical health. Differences in relationship and sexual satisfaction and social support have been identified between sexual minority women (SMW; i.e., lesbian and bisexual) and heterosexual women. However, classifying SMW into a single group may mask important differences. Further research is needed to better understand the differences in relationship and sexual satisfaction and social support between subgroups of SMW. Thus, the purpose of the present study was to examine differences in these constructs between women who identify as only lesbian, mostly lesbian, and bisexual. Participants were 427 partnered sexual minority women (Mage = 24.66; 84.8% White; 46.8% only lesbian; 34.2% mostly lesbian; 19% bisexual) recruited from social media to complete an online survey consisting of measures of relationship, health, and related factors as part of a larger study. A one-way ANOVA revealed statistically significant differences between only lesbian, mostly lesbian, and bisexual women in relationship satisfaction (p=.021), sexual satisfaction (p=.049), and social support (p=.034). Post-hoc pairwise comparisons revealed women who identified as only lesbian reported better relationship satisfaction (p=.007), sexual satisfaction (p=.015), and social support (p=.010) than women who identified as mostly lesbian. There were no differences between bisexual women and women who identified as either only lesbian or mostly lesbian. These findings identified important differences between subgroups of SMW, with women who identify as mostly lesbian reporting the lowest relationship and sexual satisfaction and social support. This study provides further evidence that collapsing across identities within the broad category of SMW may mask meaningful subgroup differences. Additional research is needed to further explore disparities in well-being among subsections of SMW. Findings may help identify important protective factors for mental and physical health and well-being specific to SMW of different identities.
Dynamical abelian anyons with bound states and scattering states
Creators: name: Bachmann, Sven
name: Nachtergaele, Bruno
name: Vadnerkar, Siddharth
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mathematical Physics (math-ph)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We introduce a family of quantum spin Hamiltonians on $\mathbb{Z}^2$ that can be regarded as perturbations of Kitaev's abelian quantum double models that preserve the gauge and duality symmetries of these models. We analyze in detail the sector with one electric charge and one magnetic flux and show that the spectrum in this sector consists of both bound states and scattering states of abelian anyons. Concretely, we have defined a family of lattice models in which abelian anyons arise naturally as finite-size quasi-particles with non-trivial dynamics that consist of a charge-flux pair. In particular, the anyons exhibit a non-trivial holonomy with a quantized phase, consistent with the gauge and duality symmetries of the Hamiltonian.
description: 21 pages, 10 figures
MPEG-G: The Standard for Genomic Information Representation
Creators: name: Voges, Jan
Publisher: name: Hannover : Institutionelles Repositorium der Leibniz Universität Hannover
Year: 2018
Subjects: subject: Genome Sequencing
subject: ISO/IEC 23092
subject: File Format
subject: Dewey Decimal Classification::000 | Allgemeines, Wissenschaft::000 | Informatik, Wissen, Systeme::004 | Informatik

description: Presentation at the SVCP 2018
The spectral type of CHS7797 - an intriguing very low mass periodic variable in the Orion Nebula Cluster
Creators: name: Rodriguez-Ledesma, M. V.
name: Mundt, R.
name: Pintado, O.
name: Boudreault, S.
name: Hessman, F.
name: Herbst, W.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present the spectroscopic characterization of the unusual high-amplitude very low mass pre-main-sequence periodic variable CHS7797. This study is based on optical medium-resolution (R=2200) spectroscopy in the 6450-8600 A range, carried out with GMOS-GEMINI-S in March 2011. Observations of CHS7797 have been carried out at two distinct phases of the 17.8d period, namely at maximum and four days before maximum. Four different spectral indices were used for the spectral classification at these two phases, all of them well-suited for spectral classification of young and obscured late M dwarfs. In addition, the gravity-sensitive NaI (8183/8195 A) and KI (7665/7699 A) doublet lines were used to confirm the young age of CHS7797. From the spectrum obtained at maximum light we derived a spectral type (SpT) of M6.05, while for the spectrum taken four days before maximum the derived SpT is M5.75. The derived SpTs confirm that CHS7797 has a mass in the stellar-substellar boundary mass range. In addition, the small differences in the derived SpTs at the two observed phases may provide indirect hints that CHS7797 is a binary system of similar mass components surrounded by a tilted circumbinary disk, a system similar to KH15D.
description: 6 pages, accepted for publication A&A
Estimation Using Quantized Innovations for Wireless Sensor Networks
Creators: name: Norris, Noele R.
Publisher: name: California Institute of Technology
Year: 2010
Subjects: wireless sensor networks
networked control systems
quantized measurements
Electrical Engineering

description: Recent advancements in integrated small scale micro-electromechanical system technology has created cheap, low power-consuming sensors that can be used in wireless sensor networks, an increasingly popular technology because of its potentially diverse applications.  However, sensor networks have many constraints, such as limited bandwidth and power, which have inspired a considerable amount of research for the development of energy efficient detection and estimation algorithms using quantized observations. Though optimal estimation algorithms using quantized innovations have been recently developed to tackle this problem, bounds are not available on the error of the resulting optimal filter. Because tight bounds on the estimation error are essential in determining the stabilizability of the corresponding closed loop dynamical system and thus the applicability of a filter to a specific system, this project focuses on developing error bounds from a close study of the filtering algorithms. Initial attempts were unable to show that the estimation error of a system using quantized innovations followed a Ricatti recursion. Thus, a number of different algorithms and coder-estimator pairs were then analyzed to determine performance and to better understand means of proving stabilizability.  Our primary goal is to have a better understanding of the evolution of the lower and upper bounds of estimation errors under measurement quantization, so that filters with verifiable performance specifications can be systematically designed for particular dynamical systems.
Geometric, Variational Discretization of Continuum Theories
Creators: name: Gawlik, Evan S.
Publisher: name: California Institute of Technology
Year: 2010
Subjects: nematic liquid crystals
variational integrators
magnetohydrodynamics
Structure-preserving integrators
microstretch continua
Applied And Computational Mathematics
geometric mechanics

description: This study derives geometric, variational discretizations of continuum theories arising in fluid dynamics, magnetohydrodynamics (MHD), and the dynamics of complex fluids.  A central role in these discretizations is played by the geometric formulation of fluid dynamics, which views solutions to the governing equations for perfect fluid flow as geodesics on the group of volume-preserving diffeomorphisms of the fluid domain.  Inspired by this framework, we construct a finite-dimensional approximation to the diffeomorphism group and its Lie algebra, thereby permitting a variational temporal discretization of geodesics on the spatially discretized diffeomorphism group.  The extension to MHD and complex fluid flow is then made through an appeal to the theory of Euler-Poincaré systems with advection, which provides a generalization of the variational formulation of ideal fluid flow to fluids with one or more advected parameters.  Upon deriving a family of structured integrators for these systems, we test their performance via a numerical implementation of the update schemes on a cartesian grid.  Among the hallmarks of these new numerical methods are exact preservation of momenta arising from symmetries, automatic satisfaction of solenoidal constraints on vector fields, good long-term energy behavior, robustness with respect to the spatial and temporal resolution of the discretization, and applicability to irregular meshes.
On the Landau-Lifshitz-Gilbert equation with magnetostriction
Creators: name: Banas, L'ubomir
name: Page, Marcus
name: Praetorius, Dirk
name: Rochat, Jonathan
Publisher: name: arXiv
Year: 2013
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics
subject: 65N30, 65N50

description: To describe and simulate dynamic micromagnetic phenomena, we consider a coupled system of the nonlinear Landau-Lifshitz-Gilbert equation and the conservation of momentum equation. This coupling allows to include magnetostrictive effects into the simulations. Existence of weak solutions has recently been shown in [Carbout et al. 2011]. In our contribution, we give an alternate proof which additionally provides an effective numerical integrator. The latter is based on lowest-order finite elements in space and a linear-implicit Euler time-stepping. Despite the nonlinearity, only two linear systems have to be solved per timestep, and the integrator fully decouples both equations. Finally, we prove unconditional convergence---at least of a subsequence---towards, and hence existence of, a weak solution of the coupled system, as timestep size and spatial mesh-size tend to zero. Numerical experiments conclude the work and shed new light on the existence of blow-up in micromagnetic simulations.
description: 22 pages, submitted for publication
Social network analysis of manga: similarities to real-world social networks and trends over decades
Creators: name: Sugishita, Kashin
name: Masuda, Naoki
Publisher: name: arXiv
Year: 2023
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Social and Information Networks (cs.SI)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Manga, Japanese comics, has been popular on a global scale. Social networks among characters, which are often called character networks, may be a significant contributor to their popularity. We collected data from 162 popular manga that span over 70 years and analyzed their character networks. First, we found that many of static and temporal properties of the character networks are similar to those of real human social networks. Second, the character networks of most manga are protagonist-centered such that a single protagonist interacts with the majority of other characters. Third, the character networks for manga mainly targeting boys have shifted to denser and less protagonist-centered networks and with fewer characters over decades. Manga mainly targeting girls showed the opposite trend except for the downward trend in the number of characters. The present study, which relies on manga data sampled on an unprecedented scale, paves the way for further population studies of character networks and other aspects of comics.
description: 17 pages, 9 figures, 1 table
Condensation of preformed charge density waves in kagome metals
Creators: name: Park, Changwon
name: Son, Young-Woo
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Charge density wave (CDW) is a spontaneous spatial modulation of electric charges in solids whose general microscopic descriptions are yet to be completed. Layered kagome metals of $A$V$_3$Sb$_5$ ($A$ = K, Rb, Cs) provide a unique chance to realize its emergence intertwined with dimensional effects as well as their special lattice. Here, based on a state-of-the-art molecular dynamics simulation, we uncover that the phase transition to charge ordered states in kagome metals is a condensation process of incoherently preformed CDWs. We demonstrate that charge modulation first preforms on each kagome layer at a well defined temperature but its phase fluctuation proliferates across the entire layers with a $10^5$ times slower frequency than typical phonon vibrations until reaching its freezing temperature. We find that the fluctuation is not random but confined to a limited number of states as a consequence of unavoidable degeneracy in stacking layered charge orders. As the size of interfacial alkali atom increases, the fluctuating phases are shown to counterbalance the condensation of orderings, resulting in a maximized transition temperature for RbV$_3$Sb$_5$. Our results resolve several controversial observations on their CDW formations and highlight a crucial role of interlayer interactions for the charge ordering in kagome metals.