cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Mechanistic and Spectroscopic Studies of Small Molecule Activating Enzymes and Biomimetic Model Complexes
Creators: name: Xue, Shan
Publisher: name: Carnegie Mellon University
Year: 2023
Subjects: Bioinorganic Chemistry

description: Meeting the energy demands of an expanding human population poses significant challenges, amplified by our dependence on diminishing non-renewable resources that contribute to climate change. The potential of small molecules, especially hydrogen (H2) and oxygen (O2), as energy sources presents a viable alternative given their abundance and role in energy conversion. This research spotlights the role of hydrogenases and non-heme iron-containing dioxygenases in enabling small molecule activation. [FeFe] hydrogenases are known to catalyze H2 generation efficiently, reaching proton reduction rates of up to 104 s-1 . This capability has prompted the development of bioinspired catalysts. Yet, current synthetic models mimicking the active center of [FeFe]-hydrogenases demonstrate far less catalytic efficiency than that of their natural counterparts. Additionally, nonheme oxygenases/oxidases, essential for activating O2 and incorporating it into natural products, exhibit varied reactivities pivotal for numerous biological pathways. These two sets of enzymes and their corresponding model complexes are the primary focus of this thesis. Specifically, this thesis covers analyses of tetra-iron [Fe4] hydrogenase model complexes, where a distinctive S=1 Fe(II) intermediate spin state was identified. Our study of the kinetics and spectroscopic properties of Fe/αKG enzymes revealed novel catalytic activities and key intermediates, deepening our understanding of their mechanisms. Computational insights further highlighted factors vital to the reactivity. We also scrutinized the key substrate-triggered reactive intermediates in a non-heme di-iron enzyme of the HDOs family. Through spectroscopic studies, DFT calculations, and MD modeling, this work aspires to enhance comprehension of these enzymes, underscoring their potential in devising sustainable energy strategies.
Polymers and Functional Graphenic Materials to Remediate Heavy Metal Exposure and Toxicity
Creators: name: Schmidt, Stephen
Publisher: name: Carnegie Mellon University
Year: 2023
Subjects: Synthesis of Materials
Theory and Design of Materials

description: Heavy metal toxicity has been known for thousands of years, but efforts are still underway to remediate their harmful effects. Exposure can occur through countless routes, ranging from domestic exposures in lead paint and contaminated drinking water, to failing metallic implants, to chronic exposures from an activity like mining, and many more. The severity of heavy metal poisoning ranges from innocuous to extremely detrimental. There exists a medical intervention known as chelation therapy to forcefully reduce heavy metal ion concentrations in the body, but these typically come with harmful and unpleasant side effects, that render the treatment, in many cases, not worth using. Patients who undergo chelation therapy typically have either had chronic exposure to heavy metals or have had a dreadful incident that resulted in extremely high internal heavy metal ion levels. While some have had success with chelation therapy, many do not, and few report having a good experience. Patients with low-level heavy metal poisoning, which comprise the vast majority, do not experience chelation therapy at all. They are left with an unideal option: eliminate any source of heavy metal exposure and wait for levels to go down naturally, which is a very slow process where progress is measured in months and years; meanwhile, toxic heavy metal ions are still circulating throughout the body. The most common situation for this unfortunate reality is with parents who have a lead poisoned child and are told by medical professionals that as long as the child is otherwise healthy, there is no effective treatment that is worth using, so they are left to wait, and hope. This thesis targets closing this gap in treatment by introducing a new approach to chelation therapy by using naturally occurring polymers and covalently modifying the structure to allow for effective heavy metal adsorption and clearance. The work presented in this thesis also targets eliminating potential sources of heavy metals, such as from food, water, and metallic implants.
Pacific hake (Merluccius productus) fish protein hydrolysates with antioxidative properties
Creators: name: Samaranayaka, Anusha Geethangani Perera
Publisher: name: University of British Columbia
Year: 2010

description: Pacific hake (Merluccius productus) is an under-valued fish with high endogenous proteolytic activity due to parasitic infection by Kudoa paniformis. The objective of this research was to produce fish protein hydrolysates (FPH) with antioxidative properties from Pacific hake and to assess their potential to inhibit oxidative processes, in vivo. Proteolytic activity of fish homogenate was optimum at pH 5.25-5.50 and 52-55°C. Significant (p<0.05) correlations were observed among fish mince K. paniformis spore counts, endogenous proteolytic activity, and content of free amino groups during autolysis. Autolysis of Kudoa-infected fish fillet mince (30 x 10⁶ spores/g) for 1 h at 52°C and pH 5.50 produced FPH with high antioxidative capacity in a linoleic acid model system, which was higher (p<0.05) than that of butylated hydroxyanisole and α-tocopherol over prolonged storage (~162 hrs). Trolox equivalent antioxidant capacity and oxygen radical absorbing capacity values of FPH were 262 ±2 and 225 ±17 μmol Trolox equivalents/g freeze-dried sample, respectively. Further, FPH could scavenge 1,1-diphenyl-2-picrylhydrazyl radicals, but iron-chelating ability was very low. When in vitro angiotensin-I-converting enzyme (ACE)-inhibitory potential was quantified to examine potential multifunctional capacity, FPH was shown to be a substrate-type inhibitor of ACE with IC₅₀ of 162 µg peptides/mL. In vitro gastrointestinal (GI)-digestion of FPH increased (P<0.05) antioxidative capacity, while ACE-inhibitory activity remained unchanged. Some peptides from FPH and GI-digested FPH passed through Caco-2 cells, and the permeates showed 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging capacity but not ACE-inhibitory activity. FPH and GI-digested FPH inhibited 2,2′-azobis-(2-amidinopropane) dihydrochloride-induced oxidation in Caco-2 cells at non-cytotoxic concentrations. Both antioxidative and ACE-inhibitory peptides were concentrated in a 1-3 kDa fraction by ultrafiltration, but the peptides having antioxidative capacity differed from those exhibiting ACE-inhibitory activity. Two peptides (PLFQDKLAHAK and AEAQKQLR) were identified and their antioxidative potential, along with three other literature reported antioxidative peptides, were assessed in different in vitro chemical systems; antioxidative capacities depended on peptide sequence, amino acid composition, and the in vitro assay system used. In conclusion, antioxidative FPH from Pacific hake could be a useful functional food ingredient. Further studies are needed to assess prospective antihypertensive effects and to identify antioxidative mechanisms of constituent peptides.
Walk ferroelectric liquid droplets with light
Creators: name: Marni, Stefano
name: Nava, Giovanni
name: Barboza, Raouf
name: Bellini, Tommaso
name: Lucchetti, Liana
Publisher: name: arXiv
Year: 2023
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We show that the motion of ferroelectric liquid sessile droplets deposited on a ferroelectric lithium niobate substrate can be controlled by a light beam of moderate intensity irradiating the substrate at a distance of several droplet diameters from the droplet itself. The ferroelectric liquid is a nematic liquid crystal in which almost complete polar ordering of the molecular dipoles generates an internal macroscopic polarization locally collinear to the mean molecular long axis. Upon entering the ferroelectric phase droplets are either attracted toward the center of the beam or repelled, depending on the side of the lithium niobate exposed to light irradiation. Moreover, moving the beam results in walking the ferroelectric droplet over long distances on the substrate. We understand this behavior as due to the coupling between the polarization of the ferroelectric droplet and the polarization photoinduced in the irradiated region of the lithium niobate substrate. Indeed, the effect is not observed in the conventional nematic phase, suggesting the crucial role of the ferroelectric liquid crystal polarization.
description: 10 pages, 6 figures
Classifying topological neural network quantum states via diffusion maps
Creators: name: Teng, Yanting
name: Sachdev, Subir
name: Scheurer, Mathias S.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We discuss and demonstrate an unsupervised machine-learning procedure to detect topological order in quantum many-body systems. Using a restricted Boltzmann machine to define a variational ansatz for the low-energy spectrum, we sample wave functions with probability decaying exponentially with their variational energy; this defines our training dataset that we use as input to a diffusion map scheme. The diffusion map provides a low-dimensional embedding of the wave functions, revealing the presence or absence of superselection sectors and, thus, topological order. We show that for the diffusion map, the required similarity measure of quantum states can be defined in terms of the network parameters, allowing for an efficient evaluation within polynomial time. However, possible ''gauge redundancies'' have to be carefully taken into account. As an explicit example, we apply the method to the toric code.
description: 18 pages, 10 figures
Optical Properties of Organic Haze Analogues in Water-rich Exoplanet Atmospheres Observable with JWST
Creators: name: He, Chao
name: Radke, Michael
name: Moran, Sarah E.
name: Horst, Sarah M.
name: Lewis, Nikole K.
name: Moses, Julianne I.
name: Marley, Mark S.
name: Batalha, Natasha E.
name: Kempton, Eliza M. -R.
name: Morley, Caroline V.
name: Valenti, Jeff A.
name: Vuitton, Veronique
Publisher: name: arXiv
Year: 2023
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: JWST has begun its scientific mission, which includes the atmospheric characterization of transiting exoplanets. Some of the first exoplanets to be observed by JWST have equilibrium temperatures below 1000 K, which is a regime where photochemical hazes are expected to form. The optical properties of these hazes, which controls how they interact with light, are critical for interpreting exoplanet observations, but relevant experimental data are not available. Here we measure the density and optical properties of organic haze analogues generated in water-rich exoplanet atmosphere experiments. We report optical constants (0.4 to 28.6 μm) of organic haze analogues for current and future observational and modeling efforts covering the entire wavelength range of JWST instrumentation and a large part of Hubble. We use these optical constants to generate hazy model atmospheric spectra. The synthetic spectra show that differences in haze optical constants have a detectable effect on the spectra, impacting our interpretation of exoplanet observations. This study emphasizes the need to investigate the optical properties of hazes formed in different exoplanet atmospheres, and establishes a practical procedure to determine such properties.
description: 4 figures, 1 Table, Published in Nature Astronomy
Is Lebesgue measure the only $σ$-finite invariant Borel measure?
Creators: name: Elekes, Márton
name: Keleti, Tamás
Publisher: name: arXiv
Year: 2011
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Mathematics
subject: Primary 28C10, Secondary 28A05, 28A10

description: R.D.Mauldin asked if every translation invariant $σ$-finite Borel measure on $\RR^d$ is a constant multiple of Lebesgue measure. The aim of this paper is to show that the answer is "yes and no", since surprisingly the answer depends on what we mean by Borel measure and by constant. We present Mauldin's proof of what he called a folklore result, stating that if the measure is only defined for Borel sets then the answer is affirmative. Then we show that if the measure is defined on a $σ$-algebra \emph{containing} the Borel sets then the answer is negative. However, if we allow the multiplicative constant to be infinity, then the answer is affirmative in this case as well. Moreover, our construction also shows that an isometry invariant $σ$-finite Borel measure (in the wider sense) on $\RR^d$ can be non-$σ$-finite when we restrict it to the Borel sets.
When it counts -- Econometric identification of the basic factor model based on GLT structures
Creators: name: Frühwirth-Schnatter, Sylvia
name: Hosszejni, Darjus
name: Lopes, Hedibert Freitas
Publisher: name: arXiv
Year: 2023
Subjects: subject: Methodology (stat.ME)
subject: Econometrics (econ.EM)
subject: FOS: Computer and information sciences
subject: FOS: Economics and business
subject: 62H25 (Primary) 15A24, 62F15 (Secondary)

description: Despite the popularity of factor models with sparse loading matrices, little attention has been given to formally address identifiability of these models beyond standard rotation-based identification such as the positive lower triangular (PLT) constraint. To fill this gap, we review the advantages of variance identification in sparse factor analysis and introduce the generalized lower triangular (GLT) structures. We show that the GLT assumption is an improvement over PLT without compromise: GLT is also unique but, unlike PLT, a non-restrictive assumption. Furthermore, we provide a simple counting rule for variance identification under GLT structures, and we demonstrate that within this model class the unknown number of common factors can be recovered in an exploratory factor analysis. Our methodology is illustrated for simulated data in the context of post-processing posterior draws in Bayesian sparse factor analysis.
The Effects of Spatial Interpolation on a Novel, Dual-Doppler 3D Wind Retrieval Technique
Creators: name: Brook, Jordan P.
name: Protat, Alain
name: Potvin, Corey K.
name: Soderholm, Joshua S.
name: McGowan, Hamish
Publisher: name: arXiv
Year: 2023
Subjects: subject: Atmospheric and Oceanic Physics (physics.ao-ph)
subject: FOS: Physical sciences

description: Three-dimensional wind retrievals from ground-based Doppler radars have played an important role in meteorological research and nowcasting over the past four decades. However, in recent years, the proliferation of open-source software and increased demands from applications such as convective parameterizations in numerical weather prediction models has led to a renewed interest in these analyses. In this study, we analyze how a major, yet often-overlooked, error source effects the quality of retrieved 3D wind fields. Namely, we investigate the effects of spatial interpolation, and show how the common practice of pre-gridding radial velocity data can degrade the accuracy of the results. Alternatively, we show that assimilating radar data directly at their observation locations improves the retrieval of important dynamic features such as the rear flank downdraft and mesocyclone within a simulated supercell, while also reducing errors in vertical vorticity, horizontal divergence, and all three velocity components.
description: Revised version submitted to JTECH. Includes new section with a real data case
Quantum Scattering States in a Nonlinear Coherent Medium
Creators: name: Brattley, Allison
name: Huang, Hongyi
name: Das, Kunal K.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Pattern Formation and Solitons (nlin.PS)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We present a comprehensive study of stationary states in a coherent medium with a quadratic or Kerr nonlinearity in the presence of localized potentials in one dimension (1D) for both positive and negative signs of the nonlinear term, as well as for barriers and wells. The description is in terms of the nonlinear Schrödinger equation (NLSE) and hence applicable to a variety of systems, including interacting ultracold atoms in the mean field regime and light propagation in optical fibers. We determine the full landscape of solutions, in terms of a potential step and build solutions for rectangular barrier and well potentials. It is shown that all the solutions can be expressed in terms of a Jacobi elliptic function with the inclusion of a complex-valued phase shift. Our solution method relies on the roots of a cubic polynomial associated with a hydrodynamic picture, which provides a simple classification of all the solutions, both bounded and unbounded, while the boundary conditions are intuitively visualized as intersections of phase space curves. We compare solutions for open boundary conditions with those for a barrier potential on a ring, and also show that numerically computed solutions for smooth barriers agree qualitatively with analytical solutions for rectangular barriers. A stability analysis of solutions based on the Bogoliubov equations for fluctuations show that persistent instabilities are localized at sharp boundaries, and are predicated by the relation of the mean density change across the boundary to the value of the derivative of the density at the edge. We examine the scattering of a wavepacket by a barrier potential and show that at any instant the scattered states are well described by the stationary solutions we obtain, indicating applications of our results and methods to nonlinear scattering problems.
description: 22 pages, 15 figures, 1 table
The digital research axis at C2DH: sustainable workflows, data usability, and multi-layered publishing
Creators: name: Viola, Lorella
name: Takats, Sean
name: Wieneke, Lars
name: Apostolopoulos, Petros
name: Lucchesi, Anita
Publisher: name: Zenodo
Year: 2023
Subjects: digital humanities infrastructure
digital heritage
sustainability

description: This panel brings together the efforts of the Centre for Contemporary and Digital History (C2DH) at the University of Luxembourg to share how through its infrastructural initiatives, digital methods and tools answer urgent questions such as: ● How does a digital infrastructure relate to the tools we use, the sources we apply them to, the way in which researchers and users work in relationship with them, but also how they work in relationship with each other?
 ● How can we host a generalizable infrastructure that ensures privacy and portability; and it will be supported by a long-term sustainability plan and training opportunities?
 ● How can we allow users to build and rebuild, and to run and rerun their own workflows or those they have adopted and adapted whilst ensuring sustainability?
 ● How can a platform allow users to contextualize artifacts by capturing their own subject expertise?
 ● How can a platform enhance users’ retrieval of meaningful content and maximise the potential of digital collections?
 ● How does an innovative publication platform promote a new form of data-driven scholarship and of transmedia storytelling in the humanities?
Pulsation models for the roAp star HD 134214
Creators: name: Saio, H.
name: Gruberbauer, M.
name: Weiss, W. W.
name: Matthews, J. M.
name: Ryabchikova, T.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Precise time-series photometry with the MOST satellite has led to identification of 10 pulsation frequencies in the rapidly oscillating Ap (roAp) star HD 134214. We have fitted the observed frequencies with theoretical frequencies of axisymmetric modes in a grid of stellar models with dipole magnetic fields. We find that, among models with a standard composition of $(X,Z) = (0.70,0.02)$ and with suppressed convection, eigenfrequencies of a $1.65\,{\rm M}_\odot$ model with $\log T_{\rm eff} = 3.858$ and a polar magnetic field strength of 4.1kG agree best with the observed frequencies. We identify the observed pulsation frequency with the largest amplitude as a deformed dipole ($\ell = 1$) mode, and the four next-largest-amplitude frequencies as deformed $\ell = 2$ modes. These modes have a radial quasi-node in the outermost atmospheric layers ($τ\sim 10^{-3}$). Although the model frequencies agree roughly with observed ones, they are all above the acoustic cut-off frequency for the model atmosphere and hence are predicted to be damped. The excitation mechanism for the pulsations of HD 134214 is not clear, but further investigation of these modes may be a probe of the atmospheric structure in this magnetic chemically peculiar star.
description: 9 pages, 6 figures; accepted for publication in MNRAS
Supplementary document for Parity-time symmetry breaking optical nanocircuit - 6378895.pdf
Creators: name: Li, Haojie
name: Jia, Qianwen
name: Lv, Bokun
name: Cao, Fengzhao
name: Yang, Guoxia
name: Liu, Dahe
name: Shi, Jinwei
Publisher: name: Optica Publishing Group
Year: 2023
Subjects: Uncategorized

description: Supplemental information
Career situation of female astronomers in Germany
Creators: name: Fohlmeister, J.
name: Helling, Ch.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: We survey the job situation of women in astronomy in Germany and of German women abroad and review indicators for their career development. Our sample includes women astronomers from all academic levels from doctoral students to professors, as well as female astronomers who have left the field. We find that networking and human support are among the most important factors for success. Experience shows that students should carefully choose their supervisor and collect practical knowledge abroad. We reflect the private situation of female German astronomers and find that prejudices are abundant, and are perceived as discriminating.We identify reasons why women are more likely than men to quit astronomy after they obtain their PhD degree. We give recommendations to young students on what to pay attention to in order to be on the successful path in astronomy.
description: published in Astronomical Notes
Supplementary document for Parity-time symmetry breaking optical nanocircuit - 6385849.pdf
Creators: name: Li, Haojie
name: Jia, Qianwen
name: Lv, Bokun
name: Cao, Fengzhao
name: Yang, Guoxia
name: Liu, Dahe
name: Shi, Jinwei
Publisher: name: Optica Publishing Group
Year: 2023
Subjects: Uncategorized

description: supplementary materials
The $γ^* γ^*\toη_c$ transition form factor
Creators: name: Lucha, Wolfgang
name: Melikhov, Dmitri
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the $γ^* γ^*\toη_c$ transition form factor, $F_{η_cγγ}(Q_1^2,Q_2^2),$ with the local-duality (LD) version of QCD sum rules. We analyse the extraction of this quantity from two different correlators, $$ and $,$ with $P,$ $A,$ and $V$ being the pseudoscalar, axial-vector, and vector currents, respectively. The QCD factorization theorem for $F_{η_cγγ}(Q_1^2,Q_2^2)$ allows us to fix the effective continuum thresholds for the $$ and $$ correlators at large values of $Q^2=Q_2^2$ and some fixed value of $β\equiv Q_1^2/Q_2^2$. We give arguments that, in the region $Q^2\ge10$--$15 GeV^2$, the effective threshold should be close to its asymptotic value such that the LD sum rule provides reliable predictions for $F_{η_cγγ}(Q_1^2,Q_2^2).$ We show that, for the experimentally relevant kinematics of one real and one virtual photon, the result of the LD sum rule for $F_{η_cγ}(Q^2)\equiv F_{η_cγγ}(0,Q^2)$ may be well approximated by the simple monopole formula $F_{η_cγ}(Q^2)={2e_c^2N_cf_P}(M_V^2+Q^2)^{-1},$ where $f_P$ is the $η_c$ decay constant, $e^2_c$ is the $c$-quark charge, and the parameter $M_V$ lies in the mass range of the lowest $\bar cc$ vector states.
description: 9 pages
Multi-frequency observations of SNR J0453-6829 in the LMC; A composite supernova remnant with a pulsar wind nebula
Creators: name: Haberl, F.
name: Filipovic, M. D.
name: Bozzetto, L. M.
name: Crawford, E. J.
name: Points, S. D.
name: Pietsch, W.
name: De Horta, A. Y.
name: Tothill, N.
name: Payne, J. L.
name: Sasaki, M.
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The Large Magellanic Cloud (LMC) is rich in supernova remnants (SNRs) which can be investigated in detail with radio, optical and X-ray observations. SNR J0453-6829 is an X-ray and radio-bright remnant in the LMC, within which previous studies revealed the presence of a pulsar wind nebula (PWN), making it one of the most interesting SNRs in the Local Group of galaxies. We study the emission of SNR J0453-6829 to improve our understanding of its morphology, spectrum, and thus the emission mechanisms in the shell and the PWN of the remnant. We obtained new radio data with the Australia Telescope Compact Array and analysed archival XMM-Newton observations of SNR J0453-6829. We studied the morphology of SNR J0453-6829 from radio, optical and X-ray images and investigated the energy spectra in the different parts of the remnant. Our radio results confirm that this LMC SNR hosts a typical PWN. The prominent central core of the PWN exhibits a radio spectral index alpha_Core of -0.04+/-0.04, while in the rest of the SNR shell the spectral slope is somewhat steeper with alpha_Shell = -0.43+/-0.01. We detect regions with a mean polarisation of P ~ (12+/-4)% at 6 cm and (9+/-2)% at 3 cm. The full remnant is of roughly circular shape with dimensions of (31+/-1) pc x (29+/-1) pc. The spectral analysis of the XMM-Newton EPIC and RGS spectra allowed us to derive physical parameters for the SNR. Somewhat depending on the spectral model, we obtain for the remnant a shock temperature of around 0.2 keV and estimate the dynamical age to 12000-15000 years. Using a Sedov model we further derive an electron density in the X-ray emitting material of 1.56 cm^-3, typical for LMC remnants, a large swept-up mass of 830 solar masses, and an explosion energy of 7.6 x 10^50 erg. These parameters indicate a well evolved SNR with an X-ray spectrum dominated by emission from the swept-up material.
description: Accepted for publication in A&A, 7 pages, 8 figures, figure 5 with lower resolution
Turbulent Vortex Flow Responses at the AB Interface in Rotating Superfluid 3He-B
Creators: name: Walmsley, P. M.
name: Eltsov, V. B.
name: Heikkinen, P. J.
name: Hosio, J. J.
name: Hanninen, R.
name: Krusius, M.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In a rotating two-phase sample of 3He-B and magnetic-field stabilized 3He-A the large difference in mutual friction dissipation at 0.20 Tc gives rise to unusual vortex flow responses. We use noninvasive NMR techniques to monitor spin down and spin up of the B-phase superfluid component to a sudden change in the rotation velocity. Compared to measurements at low field with no A-phase, where these responses are laminar in cylindrically symmetric flow, spin down with vortices extending across the AB interface is found to be faster, indicating enhanced dissipation from turbulence. Spin up in turn is slower, owing to rapid annihilation of remanent vortices before the rotation increase. As confirmed by both our NMR signal analysis and vortex filament calculations, these observations are explained by the additional force acting on the B-phase vortex ends at the AB interface.
description: 6 pages, 6 figures
Understanding the Necessary Conditions of Multi-Source Trust Transfer in Artificial Intelligence
Creators: name: Renner, Maximilian
name: Lins, Sebastian
name: Söllner, Matthias
name: Thiebes, Scott
name: Sunyaev, Ali
Publisher: name: IEEE Computer Society
Year: 2022
Subjects: trust in artificial intelligence
trust transfer
necessary condition analysis
trust in autonomous vehicles

description: Trust transfer is a promising perspective on prevalent discussions about trust in AI-capable technologies. However, the convergence of AI with other technologies challenges existing theoretical assumptions. First, it remains unanswered whether both trust in AI and the base technology is necessary for trust transfer. Second, a nuanced view on trust sources is needed, considering the dual role of trust. To address these issues, we examine whether trust in providers and trust in technologies are necessary trust conditions. We conducted a survey with 432 participants in the context of autonomous vehicles and applied necessary condition analysis. Our results indicate that trust in AI technology and vehicle technology are necessary sources. In contrast, only vehicle providers represent a necessary source. We contribute to research by providing a novel perspective on trust in AI, applying a promising data analysis method to reveal necessary trust sources, and consider duality of trust in trust transfer.
Less than $2^ω$ many translates of a compact nullset may cover the real line
Creators: name: Elekes, Márton
name: Steprāns, Juris
Publisher: name: arXiv
Year: 2011
Subjects: subject: Logic (math.LO)
subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Mathematics
subject: Primary 28E15, Secondary 03E17, 03E35

description: We answer a question of Darji and Keleti by proving that there exists a compact set $C_0\subset\RR$ of measure zero such that for every perfect set $P\subset\RR$ there exists $x\in\RR$ such that $(C_0+x)\cap P$ is uncountable. Using this $C_0$ we answer a question of Gruenhage by showing that it is consistent with $ZFC$ (as it follows e.g. from $\textrm{cof}(\iN)<2^ω$) that less than $2^ω$ many translates of a compact set of measure zero can cover $\RR$.
Theory of a continuous stripe melting transition in a two dimensional metal: Possible application to cuprates
Creators: name: Mross, David F.
name: Senthil, T.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We develop a concrete theory of continuous stripe melting quantum phase transitions in two dimensional metals and the associated Fermi surface reconstruction. Such phase transitions are strongly coupled but yet theoretically tractable in situations where the stripe ordering is destroyed by proliferating doubled dislocations of the charge stripe order. The resulting non-Landau quantum critical point (QCP) has strong stripe fluctuations which we show decouple dynamically from the Fermi surface even though static stripe ordering reconstructs the Fermi surface. We discuss connections to various stripe phenomena in the cuprates. We point out several puzzling aspects of old experimental results (Aeppli et al, Science 1997) on singular stripe fluctuations in the cuprates, and provide a possible explanation within our theory. These results may thus have been the first observation of non-Landau quantum criticality in an experiment.
description: 4.5 pages, 3 figures
Understanding nanoscale temperature gradients in magnetic nanocontacts
Creators: name: Petit-Watelot, Sébastien
name: Otxoa, Ruben Miguel
name: Manfrini, Mauricio
name: Van Roy, Wim
name: Lagae, Liesbet
name: Kim, Joo-Von
name: Devolder, Thibaut
Publisher: name: arXiv
Year: 2012
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We determine the temperature profile in magnetic nanocontacts submitted to the very large current densities that are commonly used for spin-torque oscillator behavior. Experimentally, the quadratic current-induced increase of the resistance through Joule heating is independent of the applied temperature from 6 K to 300 K. The modeling of the experimental rate of the current-induced nucleation of a vortex under the nanocontact, assuming a thermally-activated process, is consistent with a local temperature increase between 150 K and 220 K. Simulations of heat generation and diffusion for the actual tridimensional geometry were conducted. They indicate a temperature-independent efficiency of the heat sinking from the electrodes, combined with a localized heating source arising from a nanocontact resistance that is also essentially temperature-independent. For practical currents, we conclude that the local increase of temperature is typically 160 K and it extends 450 nm about the nanocontact. Our findings imply that taking into account the current-induced heating at the nanoscale is essential for the understanding of magnetization dynamics in nanocontact systems.
description: 5 pages, 5 figures
Artificial intelligence discovery of a charging protocol in a micromaser quantum battery
Creators: name: Rodríguez, Carla
name: Rosa, Dario
name: Olle, Jan
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We propose a gradient-based general computational framework for optimizing model-dependent parameters in quantum batteries (QB). We apply this method to two different charging scenarios in the micromaser QB and we discover a charging protocol for stabilizing the battery in upper-laying Hilbert space chambers in a controlled and automatic way. This protocol is found to be stable and robust, and it leads to an improved charging efficiency in micromaser QBs. Moreover, our optimization framework is highly versatile and efficient, holding great promise for the advancement of QB technologies at all scales.
description: Update to match journal version
A numerical adaptation of SAW identities from the honeycomb to other 2D lattices
Creators: name: Beaton, Nicholas R
name: Guttmann, Anthony J
name: Jensen, Iwan
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mathematical Physics (math-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Recently, Duminil-Copin and Smirnov proved a long-standing conjecture by Nienhuis that the connective constant of self-avoiding walks on the honeycomb lattice is $\sqrt{2+\sqrt{2}}.$ A key identity used in that proof depends on the existence of a parafermionic observable for self-avoiding walks on the honeycomb lattice. Despite the absence of a corresponding observable for SAW on the square and triangular lattices, we show that in the limit of large lattices, some of the consequences observed on the honeycomb lattice persist on other lattices. This permits the accurate estimation, though not an exact evaluation, of certain critical amplitudes, as well as critical points, for these lattices. For the honeycomb lattice an exact amplitude for loops is proved.
description: 21 pages, 7 figures. Changes in v2: Improved numerical analysis, giving greater precision. Explanation of why we observe what we do. Extra references
Steady swimming in the pufferfish Diodon holocanthus : propulsive momentum enhancement is an adaptation for thrust production in undulatory median and/or paired fin swimmers
Creators: name: Chan, Keith
Publisher: name: University of British Columbia
Year: 2010

description: Lighthill and Blake (1990) developed a form of elongated body theory appropriate for the analysis of undulatory fins attached to a rigid body and proposed a possible benefit due to momentum enhancement relative to the fins “on their own.” In this study, the magnitude of this momentum enhancement was determined by particle image velocimetry (PIV). This momentum enhancement depends on the ratio between half body depth for the major body axis s and the distance from the body midline to the fin tip l (s/l) and the half body depth for the minor axis i and s (i/s). The theoretical momentum enhancement factor for Diodon holocanthus were of the order of 2.2 and 2.7 for the median and pectoral fins respectively and compared well with inferred values based on thrust determined from PIV wake measurements with factors ranging from 2.2 - 2.4 and 2.7 - 2.9. Mean theoretical thrust for the caudal fin with no provision for momentum enhancement was compared to those measured from PIV and no significant difference was found (P > 0.05). There was no significant difference between the average sum of the total fin thrust and fish drag (P > 0.05). Pectoral fin thrust was half that of the median and caudal fins due to high jet angles, low circulation and momentum. Pectoral fin lift was insufficient to overcome the excess weight over buoyancy of the fish, implying weight support from the swim bladder and/or the body. Vortex rings generated by the fins were elliptical and depended on fin chord and amplitude. Hydrodynamic advantages are likely universal among rigid bodied organisms propelled by undulatory fins with the extent of momentum enhancement dependent on fin number, position, s/l and i/s. However, a trade-off between momentum enhancement and thrust generation sets a practical limit to the former. When s/l and i/s are large (small fins), whilst momentum enhancement is high, low absolute thrust is produced to propel a body of large surface area with consequent high drag. Limits to enhancement are also set by reductions in propulsive force associated with progressive reductions in fin wavelength.
MPEC 2023-X38 : 2020 KT4
Creators: name: Minor Planet Center Staff
Publisher: name: The Minor Planet Center
Year: 2023
Subjects: subject: Small Solar System bodies
valueUri: http://astrothesaurus.org/uat/1469

description: The Minor Planet Electronic Circulars contain information on unusual minor planets, routine data on comets and natural satellites, and occasional editorial announcements.  They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Inferring pointwise diffusion properties of single trajectories with deep learning
Creators: name: Requena, Borja
name: Masó, Sergi
name: Bertran, Joan
name: Lewenstein, Maciej
name: Manzo, Carlo
name: Muñoz-Gil, Gorka
Publisher: name: arXiv
Year: 2023
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Biological Physics (physics.bio-ph)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Quantitative Methods (q-bio.QM)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: In order to characterize the mechanisms governing the diffusion of particles in biological scenarios, it is essential to accurately determine their diffusive properties. To do so, we propose a machine learning method to characterize diffusion processes with time-dependent properties at the experimental time resolution. Our approach operates at the single-trajectory level predicting the properties of interest, such as the diffusion coefficient or the anomalous diffusion exponent, at every time step of the trajectory. In this way, changes in the diffusive properties occurring along the trajectory emerge naturally in the prediction, and thus allow the characterization without any prior knowledge or assumption about the system. We first benchmark the method on synthetic trajectories simulated under several conditions. We show that our approach can successfully characterize both abrupt and continuous changes in the diffusion coefficient or the anomalous diffusion exponent. Finally, we leverage the method to analyze experiments of single-molecule diffusion of two membrane proteins in living cells: the pathogen-recognition receptor DC-SIGN and the integrin $\alpha5\beta1$. The analysis allows us to characterize physical parameters and diffusive states with unprecedented accuracy, shedding new light on the underlying mechanisms.
description: 17 pages, 9 figures, 1 table. Code is found in https://github.com/BorjaRequena/step
Structural Hamiltonian of the international trade network
Creators: name: Fronczak, Agata
Publisher: name: arXiv
Year: 2012
Subjects: subject: General Finance (q-fin.GN)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Economics and business
subject: FOS: Physical sciences

description: It is common wisdom that no nation is an isolated economic island. All nations participate in the global economy and are linked together through trade and finance. Here we analyze international trade network (ITN), being the network of import-export relationships between countries. We show that in each year over the analyzed period of 50 years (since 1950) the network is a typical representative of the ensemble of maximally random networks. Structural Hamiltonians characterizing binary and weighted versions of ITN are formulated and discussed. In particular, given binary representation of ITN (i.e. binary network of trade channels) we show that the network of partnership in trade is well described by the configuration model. We also show that in the weighted version of ITN, bilateral trade volumes (i.e. directed connections which represent trade/money flows between countries) are only characterized by the product of the trading countries' GDPs, like in the famous gravity model of trade.
description: Presented at Summer Solstice 2011 Conference on Discrete Models of Complex Systems, Turku, Finland (15 pages, 3 figures)
Presence of a (1x1) oxygen overlayer on bare ZnO(0001) surfaces and at Schottky interfaces
Creators: name: Schlepütz, Christian M.
name: Yang, Yongsoo
name: Husseini, Naji S.
name: Heinhold, Robert
name: Kim, Hyung-Suk
name: Allen, Martin W.
name: Durbin, Steven M.
name: Clarke, Roy
Publisher: name: arXiv
Year: 2011
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The atomic surface and interface structure of bare and metal-coated ZnO(0001) Zn-polar wafers were investigated via surface x-ray diffraction. All bare samples showed the presence of a (1x1) overlayer of oxygen atoms located at the on-top position above the terminating Zn atom, a structure predicted to be unstable by several density functional theory calculations. The same oxygen overlayer is clearly seen at the interface of ZnO with both elemental and oxidized metal contact layers. No significant atomic relaxations are observed at surfaces and interfaces processed under typical device fabrication conditions.
description: 4 pages, 3 figures
Covering locally compact groups by less than $2^\om$ many translates of a compact nullset
Creators: name: Elekes, Márton
name: Tóth, Árpád
Publisher: name: arXiv
Year: 2011
Subjects: subject: Logic (math.LO)
subject: FOS: Mathematics
subject: Primary 22B05, 28C10, 03E17, Secondary 28E15, 03E35

description: Gruenhage asked if it was possible to cover the real line by less than continuum many translates of a compact nullset. Under the Continuum Hypothesis the answer is obviously negative. Elekes and Steprāns gave an affirmative answer by showing that if $C_{EK}$ is the well known compact nullset considered first by Erd\H os and Kakutani then $\RR$ can be covered by $\cof(\iN)$ many translates of $C_{EK}$. As this set has no analogue in more general groups, it was posed as an open question whether such a result holds for uncountable locally compact Polish groups. In this paper we give an affirmative answer in the abelian case. More precisely, we show that if $G$ is a nondiscrete locally compact abelian group in which every open subgroup is of index at most $\cof(\iN)$ then there exists a compact set $C$ of Haar measure zero such that $G$ can be covered by $\cof(\iN)$ many translates of $C$. This result, which is optimal in a sense, covers the cases of uncountable compact abelian groups and of nondiscrete separable locally compact abelian groups. We use Pontryagin's duality theory to reduce the problem to three special cases; the circle group, countable products of finite discrete abelian groups, and the groups of $p$-adic integers, and then we solve the problem on these three groups separately. In addition, using representation theory, we reduce the nonabelian case to the classes of Lie groups and profinite groups, and we also settle the problem for Lie groups. We remark that M.~Abért recently gave an affirmative answer for profinite groups.
Spatial correlations in glass-forming liquids across the mode-coupling crossover
Creators: name: Kob, Walter
name: Roldan-Vargas, Sandalo
name: Berthier, Ludovic
Publisher: name: arXiv
Year: 2012
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: We discuss a novel approach, the point-to-set correlation functions, that allows to determine relevant static and dynamic length scales in glass-forming liquids. We find that static length scales increase monotonically when the temperature is lowered, whereas the measured dynamic length scale shows a maximum around the critical temperature of mode-coupling theory. We show that a similar non-monotonicity is found in the temperature evolution of certain finite size effects in the relaxation dynamics. These two independent sets of results demonstrate the existence of a change in the transport mechanism when the glass-former is cooled from moderately to deeply supercooled states across the mode-coupling crossover and clarify the status of the theoretical calculations done at the mean field level.
description: 10 pages
RECAMBIO PLASMÁTICO TERAPÉUTICO EN MONOTERAPIA EN EL SÍNDROME DE GUILLAIN BARRÉ: REPORTE DE CASO
Creators: name: Sánchez Cornejo, John
name: Gutiérrez Gómez, Alex
name: Laínez Del Pezo, Walter
name: Gutiérrez Gómez, Roberto
Publisher: name: Zenodo
Year: 2023

description: El síndrome de Guillain Barré es una patología autoinmune de causa multifactorial donde la evidencia clínica es clara sobre el beneficio del tratamiento temprano, minorando sus efectos adversos a corto y largo plazo. A pesar de ser considerada una entidad rara, su impacto significativo en la calidad de vida y la salud pública subraya la importancia de una comprensión profunda y actualizada de las estrategias terapéuticas disponibles. Nuestro caso es de suma relevancia ya que nos permite analizar la literatura médica referente a los múltiples casos tratados con recambio plasmático e inmunoglobulinas de forma individual o combinada, así como la efectividad de estos enfoques terapéuticos en la mejoría de los síntomas y la recuperación de los pacientes. Esto es crucial para afinar las recomendaciones de tratamiento, mejorar la atención médica y contribuir al avance del conocimiento científico en este campo.
Impact Evidence - Research recognised, recommended and disseminated to the public on the SCIE website
Creators: name: Admin, CardiffMet
Publisher: name: Cardiff Metropolitan University
Year: 2023
Subjects: Research, science and technology policy

description: Research recognised, recommended and disseminated to the public on the Social Care Institute for Excellence website: a. https://www.scie.org.uk/prevention/research?practice/getdetailedresultbyid?id=a110f00000NXsByAAL, confirming the LAUGH research is included on the Social Care Institute for Excellence website