cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Vacuum decay and the transmission resonances in space-dependent electric fields
Creators: name: Dumlu, Cesim K.
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We investigate the decay of quantum electrodynamical (QED) vacuum in arbitrary space-dependent electric fields. In particular, we analyze the resonance peaks of the positron emission spectrum for the external fields with subcycle structure. For this, we study the transmission probability in the framework of scattering approach to vacuum pair production. In under-the-barrier scattering regime, we show that the width of a transmission resonance can be enhanced when the effective scattering potential contains multiple wells. Such a broadening in the resonance width corresponds to a decrease in the tunneling time. This may be relevant for observing the vacuum decay at shorter timescales before the external field is adiabatically turned off. In above-the-barrier scattering regime, we give a set of coupled differential equations for the numerical computation of the Bogoliubov coefficients.
description: 11 pages, 5 figures. v2: Revised and extended, to appear in PRD
Two-fluid description of two-band superconductors
Creators: name: Bittner, Nikolaj
name: Einzel, Dietrich
Publisher: name: arXiv
Year: 2013
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We present a systematic study of the response properties of two-band (multi-gap) superconductors with spin-singlet (s-wave) pairing correlations, which are assumed to be caused by both intraband (λ_{ii}, i=1,2) and interband (λ_{12}) pairing interactions. In this first of three planned publications we concentrate on the properties of such superconducting systems in global and local thermodynamic equilibrium, the latter including weak perturbations in the stationary long-wavelength limit. The discussion of global thermodynamic equilibrium must include the solution (analytical in the Ginzburg-Landau and the low temperature limit) of the coupled self-consistency equations for the two energy gaps Δ_i(T), i=1,2. These solutions allow to study non-universal behavior of the two relevant BCS-Mühlschlegel parameters, namely the specific heat discontinuity ΔC/C_N and the zero temperature gaps Δ_i(0)/πk_B T_c, i=1,2. The discussion of a local equilibrium situation includes the calculation of the supercurrent density as a property of the condensate, and the calculation of both the specific heat capacity and the spin susceptibility as properties of the gas of thermal excitations in the spirit of a microscopic two-fluid description. Non-monotonic behavior in the temperature dependences of the gaps and all these local response functions is predicted to occur particularly for very small values of the interband pair-coupling constant λ_{12}.
description: 22 pages, 8 figures
title: ПАНДЕМИЯ COVID-19 КАК СПОСОБ ОБОГАЩЕНИЯ ЛЕКСИЧЕСКОГО СОСТАВААНГЛИЙСКОГО ЯЗЫКА
Creators: name: Рыбакова, Анна Сергеевна
Publisher: name: Астраханский государственный медицинский университет
Year: 2022
Subjects: subject: Languages and literature
subject: FOS: Languages and literature

description: В  данной  статье  автор  рассматривает  термины,  которые  появились  в современном английском языке начиная с 2020 года, когда мир охватила пандемия COVID-19, а  именно  слова  с  терминоэлементом covid.  Также  приводится  анализ  аффиксов,  которые принимали участие в процессе образования новых слов с элементом covid.
Self-consistent covariant description of vector meson decay constants and chirality-even quark-antiquark distribution amplitudes up to twist-3 in the light-front quark model
Creators: name: Choi, Ho-Meoyng
name: Ji, Chueng-Ryong
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Although the meson decay amplitude described by a two-point function may be regarded as one of the simplest possible physical observable, it is interesting that this apparently simple amplitude bears abundant fundamental informations on QCD vacuum dynamics and chiral symmetry. The light-front zero-mode issue of the vector meson decay constant $f_V$ is in this respect highly non-trivial and deserves careful analyses. We discuss the zero-mode issue in the light-front quark model (LFQM) prediction of $f_V$ from the perspective of the vacuum fluctuation consistent with the chiral symmetry of QCD. We extend the exactly solvable manifestly covariant Bethe-Salpeter model calculation to the more phenomenologically accessible realistic LFQM and present a self-consistent covariant description of $f_V$ analyzing the twist-2 and twist-3 quark-antiquark distribution amplitudes with even chirality.
description: 16 pages, 4 figures
Bayesian analysis of jointly heavy-tailed data
Creators: name: Palacios Ramırez, Karla Vianey
Publisher: name: The University of Edinburgh
Year: 2022
Subjects: Bayesian statistics
heavy-tailed data analysis
Extreme value statistics

description: This thesis develops novel Bayesian methodologies for statistical modelling of heavy-tailed data. Heavy tails are often found in practice, and yet they are an Achilles heel of a variety of main-stream random probability measures such as the Dirichlet process. The first contribution of this thesis is the study of random probability measures that can be used to model heavy-tailed data, focusing on the characterization of the tails of the so-called Pitman–Yor process, which includes the Dirichlet process as a particular case. We show that the right tail of a Pitman–Yor process, known as the stable law process, is heavy-tailed, provided that the centering distribution is itself heavy-tailed. Empowered by this finding we developed two classes of heavy-tailed mixture models and assessed their relative merits. Multivariate extensions of the proposed heavy-tailed mixtures are also devised along with a predictor-dependent version so to learn about the effect of covariates on a multivariate heavy-tailed response. Another contribution of the thesis is a framework for learning about the frequency and magnitude of extreme values in the joint tail as well as in other risk sets induced by a suitable aggregation of variables on a common scale. The proposed framework reveals explicit links between nonstationary multivariate extremes and heteroscedastic extremes, and hence can be used to track the dynamics governing the degree of association between the extremes of a random vector over time. Bayesian inference methods are conducted for the two targets of interest: the structure scedasis function and the coefficient of tail dependence for structure processes. To learn about the structure scedasis function from data, we resort to a Bayesian nonparametric approach that defines a prior in the space of structure scedasis functions. A battery of numerical experiments is used to study the finite sample performance of all methodological developments made in this thesis. Data from the fields of neuroscience as well as from finance are used to showcase the proposed methodologies in practice.
Credit Risk and the Instability of the Financial System: an Ensemble Approach
Creators: name: Schmitt, Thilo A.
name: Chetalova, Desislava
name: Schäfer, Rudi
name: Guhr, Thomas
Publisher: name: arXiv
Year: 2013
Subjects: subject: Risk Management (q-fin.RM)
subject: FOS: Economics and business

description: The instability of the financial system as experienced in recent years and in previous periods is often linked to credit defaults, i.e., to the failure of obligors to make promised payments. Given the large number of credit contracts, this problem is amenable to be treated with approaches developed in statistical physics. We introduce the idea of ensemble averaging and thereby uncover generic features of credit risk. We then show that the often advertised concept of diversification, i.e., reducing the risk by distributing it, is deeply flawed when it comes to credit risk. The risk of extreme losses remain due to the ever present correlations, implying a substantial and persistent intrinsic danger to the financial system.
The Paradoxical Effect of Umbrella Clauses and African States' Interference With International Investment Contracts and BITs
Creators: name: Magoge, Jackson Simango
Publisher: name: figshare
Year: 2023
Subjects: classificationCode: 480308
subject: International trade and investment law

description: One of the safeguards that African countries’ investment treaties usually provide to international investors and their investments is “The umbrella clause,” which compels the host state of the investment to honor the obligations it has made to the foreign investor or its investment. This might be an extremely effective safeguard. However, the Umbrella clauses, on the other hand, have proven to be one of the most contentious clause(s) in investment treaties, resulting in contradictory interpretations by tribunals and commentators that have yet to be resolved. Consequently, the conditions of international investment agreements agreed upon with foreign investors have been brazenly ignored, canceled, or altered by African state parties. The rise in the number of investor-state disputes in Africa before various arbitral tribunals, which point to a widespread lack of compliance with treaty commitments, mostly by African host nations, demonstrates this. Thus, this study explains the concept of the umbrella clause and its interpretations conundrum as well as examines the reasons for African governmental intervention with BITs and the underlying contracts with foreign investors in-depth.
Nanoantennas for ultrabright single photon sources
Creators: name: Filter, Robert
name: Slowik, Karolina
name: Straubel, Jakob
name: Lederer, Falk
name: Rockstuhl, Carsten
Publisher: name: arXiv
Year: 2013
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We propose to use nanoantennas coupled to incoherently pumped quantum dots for ultra-bright single photon emission. Besides fully quantum calculations, we analyze an analytical expression for the emitted photon rate. From these analytical considerations it turns out that the Purcell factor and the pumping rate are the main quantities of interest. We also disclose a trade-off between the emitted photon rate and the nonclassical nature of the emitted light. This trade-off has to be considered while designing suitable nanoantennas, which we also discuss in depth.
Infrared Observations of Saturn’s Aurorae, Ionosphere and Thermosphere
Creators: name: Chowdhury, Mohammad N.
Publisher: name: University of Leicester
Year: 2022
Subjects: Uncategorized

description: This thesis presents analyses of infrared spectral observations of Saturn’s northern H+3 aurorae. These very high spectrally resolved data facilitated investigations of ion flows in the planet’s ionosphere and the thermospheric temperature, thus elucidating the driver of planetary andmagnetospheric periodicities witnessed at Saturn. Using observations taken in May 2013 with the VLT-CRIRES instrument – previously available at the European Southern Observatory’s Very Large Telescope – an investigation of the H+3 auroral emission intensity, ion line-of-sight velocity (derived from Doppler shifts of a H+3 emission line), and rotational temperature directly along the northern pole (perpendicular to the axis of planetary rotation) was carried out. Evidence of a dawn-enhanced auroral emission with an average temperature of 399 (±49) K, including a localised dark region within the emission co-located with an ∼1 km s−1 noon-to-midnight (and vice versa) ion flow in the H+3 line-of-sight velocity, tantalisingly hinted at the presence of an ionospheric polar vortex. Mapped observations from June, July and August 2017 of Saturn’s northern aurorae taken using the Keck-NIRSPEC instrument were used to further investigate H+3 ion flows after initially grouping individual spectra into quadrants of northern planetary magnetic phase. Comparing the H+3 ion line-of-sight velocities from opposing phase quadrants led to a direct detection of the ionospheric ‘twin-vortex’ mechanism, thus confirming that the upper atmosphere drives these current systems. The Keck-NIRSPEC data were also used to compute the H+3 rotational temperature after grouping them into the same rotational phase quadrants as for the ion line-ofsight velocities. Despite the relatively poor signal of the H+3 R(2,2−) emission line, the temperature profiles did not reveal any evidence of a localised thermal ‘hot spot’. This suggests that the driving mechanism for the planetary period currents may not be situated within the neutral thermosphere as had been hypothesised.
Ekpyrotic Perturbations With Small Non-Gaussian Corrections
Creators: name: Fertig, Angelika
name: Lehners, Jean-Luc
name: Mallwitz, Enno
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The entropic mechanism for producing nearly scale-invariant density perturbations in a contracting ekpyrotic universe relies on having an unstable scalar potential. Here we develop a variant of this mechanism (recently proposed by Qiu, Gao and Saridakis, and by Li), in which there exists a non-trivial coupling between adiabatic and entropic fields, and where an unstable potential is not required. In the model nearly scale-invariant entropy perturbations are generated first. Remarkably, we find that the bispectrum of these perturbations vanishes, with the values of the non-Gaussianity parameters of local, equilateral and orthogonal type all exactly zero. Subsequently, the entropy perturbations can be converted into curvature perturbations by a variety of mechanisms. The bispectrum of the curvature perturbations depends on the non-linearity of the conversion process and is thus more model-dependent - however, for an efficient conversion process the final bispectrum remains small. The only distinguishing feature compared to single-field slow-roll inflationary models is an absence of primordial gravitational waves. Thus the present model provides a perfect match to current data from the PLANCK satellite.
description: 5 pages, v2: references added
Efficiently Extracting Energy from Cosmological Neutrinos
Creators: name: Hedman, M. M.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Detecting the extremely low-energy neutrinos that form the Cosmic Neutrino Background (CNB) presents many experimental challenges, but pursuing this elusive goal is still worthwhile because these weakly-interacting particles could provide a new window into the structure and composition of the early universe. This report examines whether cosmological neutrinos can deposit sufficient energy into a target system to be detectable with plausible extensions of current bolometric technologies. While the macroscopic wavelengths of cosmological neutrinos can greatly enhance their cross sections with dense targets, such interactions can only be detectable if they transfer a significant fraction of each neutrino's kinetic energy into the detector system. We find that a large array of dense target masses coupled to suitable motion-sensitive circuits could potentially satisfy both of these conditions and thus might be able to serve as the basis for a more practical cosmological neutrino detector.
description: 16 pages, 2 figures, submitted to JCAP
Hole Spin Helix: Anomalous Spin Diffusion in Anisotropic Strained Hole Quantum Wells
Creators: name: Sacksteder, Vincent E.
name: Bernevig, B. Andrei
Publisher: name: arXiv
Year: 2013
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We obtain the spin-orbit interaction and spin-charge coupled transport equations of a two-dimensional heavy hole gas under the influence of strain and anisotropy. We show that a simple two-band Hamiltonian can be used to describe the holes. In addition to the well-known cubic hole spin-orbit interaction, anisotropy causes a Dresselhaus-like term, and strain causes a Rashba term. We discover that strain can cause a shifting symmetry of the Fermi surfaces for spin up and down holes. We predict an enhanced spin lifetime associated with a spin helix standing wave similar to the Persistent Spin Helix which exists in the two-dimensional electron gas with equal Rashba and Dresselhaus spin-orbit interactions. These results may be useful both for spin-based experimental determination of the Luttinger parameters of the valence band Hamiltonian and for creating long-lived spin excitations.
Edge states in bilayer graphene in a magnetic field
Creators: name: Pyatkovskiy, P. K.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Edge states in biased bilayer graphene in a magnetic field are studied within the four-band continuum model. The analysis is done for the semi-infinite graphene plane and for the graphene ribbon of a finite width, in the cases of zigzag and armchair edges. Exact dispersion equations for the edge states and analytic expressions for their wave functions are written in terms of the parabolic cylinder functions. The spectrum of edge states for each type of the boundary conditions is found by numerically solving the corresponding dispersion equations. The low-energy modes localized at zigzag edges are explored in detail.
description: 15 pages, 8 figures, v2: to match published version
The effect of linkage on establishment and survival of locally beneficial mutations
Creators: name: Aeschbacher, Simon
name: Buerger, Reinhard
Publisher: name: arXiv
Year: 2013
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: Genomics (q-bio.GN)
subject: FOS: Biological sciences

description: When organisms adapt to spatially heterogeneous environments, selection may drive divergence at multiple genes. If populations under divergent selection also exchange migrants, we expect genetic differentiation to be high at selected loci, relative to the baseline caused by migration and genetic drift. Indeed, empirical studies have found peaks of putatively adaptive differentiation. These are highly variable in length, some of them extending over several hundreds of thousands of base pairs. How can such 'islands of divergence' be explained? Physical linkage produces elevated levels of differentiation at loci close to genes under selection. However, whether this is enough to account for the observed patterns of divergence is not well understood. Here, we investigate the fate of a locally beneficial mutation that arises in linkage to an existing migration-selection polymorphism and derive two important quantities: the probability that the mutation becomes established, and the expected time to its extinction. We find that intermediate levels of recombinations are sometimes favourable, and that physical linkage can lead to strongly elevated invasion probabilities and extinction times. We provide a rule of thumb for when this is the case. Moreover, we quantify the long-term effect of polygenic local adaptation on linked neutral variation.
description: This is a revised version based on comments and suggestions by S. Yeaman and S. Flaxman
Post-subduction magmatism and mineralisation: the Tuvatu gold-telluride deposit, Fiji.
Creators: name: Clarke, Rose H.
Publisher: name: University of Leicester
Year: 2022
Subjects: Uncategorized

description: Post-subduction, alkaline magmas host some of the world’s largest gold deposits, which show enrichments in other elements, including the critical element tellurium. Fiji is home to several of these enigmatic deposits, including Tuvatu. Mineralised magmatic centres across Fiji formed following subduction cessation and plate-boundary reconfiguration. Through detailed geochemical analysis of 93 new samples, I show that compared to syn-subduction magmas, post-subduction suites have elevated concentrations of Ba, Rb, Sr, and K2O, and Nb-Ta depletions. Geochemical modelling suggests syn-subduction fractionation formed cumulates containing biotite, which were re-activated during post-subduction, liberating trace elements and metals. Through detailed, quantitative mineralogy of Tuvatu I show that the alkaline monzonite there hosts two styles of mineralisation: the Main Zone (laterally extensive veinlets of quartz, carbonates, minor sulfides, tellurides, and native-Au), and the HT zone (vuggy rock containing quartz, biotite, apatite, magnetite, sulfides, native-Au, and lesser carbonate and tellurides). Precious-metal tellurides dominate Au deportment, contributing 5x more Au by weight than native-Au. There is evidence of multiple fluid phases and zoning with depth. Mineral assemblages suggest high temperatures (>250°C) which may allow Au and other metals to remain as semi-metal melts. These aid the transfer of precious-metals into the ore-forming environment, alongside other processes recognised in the crustal continuum of post-subduction ore deposits, including CO2-facilitated transport of metals, and high pH hydrothermal fluids. Through an assessment of critical metals as by-products, I suggest that recovery of Te alongside Au could impact apportioning of carbon between metals and influence the environmental credentials of a deposit. Post-subduction, alkaline magmas can enable processes which support the development of precious- and critical-metal rich ore deposits and offer a potential source from which those metals might be more sustainably produced together, rather than in separate, single-metal mines.
W-propagator corrections to muon and tau leptonic decays
Creators: name: Fael, M.
name: Mercolli, L.
name: Passera, M.
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We derive the corrections induced by the W-boson propagator to the differential rates of the leptonic decay of a polarized muon and tau lepton. Results are presented both for decays inclusive of inner bremsstrahlung as well as for radiative ones, when a photon emitted in the decay process is measured. The numerical effect of these corrections is discussed. The definition of the Fermi constant is briefly reviewed.
description: 5 pages, no figures, accepted for publication
A Gap Theorem for Willmore Tori and an application to the Willmore Flow
Creators: name: Mondino, Andrea
name: Nguyen, Huy The
Publisher: name: arXiv
Year: 2013
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics

description: In 1965 Willmore conjectured that the integral of the square of the mean curvature of a torus immersed in $R^3$ is at least $2π^2$ and attains this minimal value if and only if the torus is a Möbius transform of the Clifford torus. This was recently proved by Marques and Neves. In this paper, we show for tori there is a gap to the next critical point of the Willmore energy and we discuss an application to the Willmore flow. We also prove an energy gap from the Clifford torus to surfaces of higher genus.
description: 9 pages. In this new version we performed some small changes to improve the exposition. To appear in Nonlinear Analysis: Theory Methods & Applications
Relative Bogomolov extensions
Creators: name: Grizzard, Robert
Publisher: name: arXiv
Year: 2013
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 11R04, 11R21, 11G50, 11S05, 12F05

description: An algebraic extension K of the rationals has the Bogomolov property if the absolute logarithmic height of non-torsion points of K* is bounded away from 0. We define a relative extension L/K to be Bogomolov if this holds for points of L\K. We construct various examples of extensions which are and are not Bogomolov. We prove a ramification criterion for this property, and use it to show that such extensions can always be constructed if some rational prime has bounded ramification index in K, when K is Galois over Q.
description: 12 pages
Studies examining the role of IL-33 and IL1RL1 (ST2) in human ILC2 function
Creators: name: Alshammari, Mohammed
Publisher: name: University of Leicester
Year: 2022
Subjects: Uncategorized

description: Asthma is a heterogeneous disease characterised by frequent airway obstruction in the lung resulting from allergic (atopic) or non-allergic (non-atopic) triggers. Allergic asthma is associated with airway inflammation and is characterised by the infiltration of inflammatory cells including eosinophils, mast cells and T-helper 2 cells (TH2). Several soluble mediators have been shown to play a critical role in the pathogenicity of allergic asthma. These mediators include the hallmark TH2 cytokines interleukin (IL)-4, IL-5 and IL-13 and the epithelial-derived cytokines IL-25, IL-33 and Thymic Stromal Lymphopoietin (TSLP). Until recently, it was believed that allergic inflammation is linked to the CD4+ TH2 cells and mast cells. However, the recently discovered group 2 innate lymphoid cells (ILC2s) have been found to play an important role in mucosal surfaces including airway tracts, as they have the capacity to produce TH2 cytokines including IL-4, IL-5 and IL-13 upon stimulation with IL-25, IL-33 and TSLP. Interleukin 1 receptor-like 1 (IL1RL1), also known as ST2, with its ligand IL33, induces allergic inflammation due to the release of type 2 cytokines. The biology of ST2 is complex because it is expressed in two forms, the soluble protein sST2, which down regulates TH2 responses, and the transmembrane form ST2 (ST2 or ST2L). Several studies have demonstrated that ST2 is expressed by ILC2s in mice; however, it is unclear from the literature whether human ILC2s express ST2. Therefore, the aims of this project were to validate antibodies to ST2 and to use validated antibodies to examine ST2 expression on human peripheral blood samples, in particular ILC2s. We hypothesised that ST2 may be upregulated on human ILC2s from asthmatic subjects compared to healthy controls. The results demonstrated that most of the commonly used ST2 antibodies were not specific to ST2, calling into question several of the published reports in the literature. Despite identifying an appropriate antibody for use in flow cytometry, it was not possible to complete the assessment of ST2 expression in asthma due to the COVID19 pandemic.
Spectro-Thermometry of M dwarfs and their candidate planets: too hot, too cool, or just right?
Creators: name: Mann, Andrew W.
name: Gaidos, Eric
name: Ansdell, Megan
Publisher: name: arXiv
Year: 2013
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We use moderate-resolution spectra of nearby late K and M dwarf stars with parallaxes and interferometrically determined radii to refine their effective temperatures, luminosities, and metallicities. We use these revised values to calibrate spectroscopic techniques to infer the fundamental parameters of more distant late-type dwarf stars. We demonstrate that, after masking out poorly modeled regions, the newest version of the PHOENIX atmosphere models accurately reproduce temperatures derived bolometrically. We apply methods to late-type hosts of transiting planet candidates in the Kepler field, and calculate effective temperature, radius, mass, and luminosity with typical errors of 57 K, 7%, 11%, and 13%, respectively. We find systematic offsets between our values and those from previous analyses of the same stars, which we attribute to differences in atmospheric models utilized for each study. We investigate which of the planets in this sample are likely to orbit in the circumstellar habitable zone. We determine that four candidate planets (KOI 854.01, 1298.02, 1686.01, and 2992.01) are inside of or within 1-sigma of a conservative definition of the habitable zone, but that several planets identified by previous analyses are not (e.g. KOI 1422.02 and KOI 2626.01). Only one of the four habitable-zone planets is Earth sized, suggesting a downward revision in the occurrence of such planets around M dwarfs. These findings highlight the importance of measuring accurate stellar parameters when deriving parameters of their orbiting planets.
description: 17 pages, 16 figures, accepted to ApJ. Added requisite significant Figures to Equations 6-8. Fixed a formatting error in the machine readable tables. All spectra now downloadable from http://www.as.utexas.edu/~amann/files/th_spec/
Growing dust grains in protoplanetary discs - I. Radial drift with toy growth models
Creators: name: Laibe, Guillaume
name: Gonzalez, Jean-François
name: Maddison, Sarah T.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: In a series of papers, we present a comprehensive analytic study of the global motion of growing dust grains in protoplanetary discs, addressing both the radial drift and the vertical settling of the particles. Here we study how the radial drift of dust particles is affected by grain growth. In a first step, toy models in which grain growth can either be constant, accelerate or decelerate are introduced. The equations of motion are analytically integrable and therefore the grains dynamics is easy to understand. The radial motion of growing grains is governed by the relative efficiency of the growth and migration processes which is expressed by the dimensionless parameter Lambda, as well as the exponents for the gas surface density and temperature profiles, denoted p and q respectively. When Lambda is of order unity, growth and migration are strongly coupled, providing the most efficient radial drift. For the toy models considered, grains pile up when -p+q+1/2<0. Importantly, we show the existence of a second process which can help discs to retain their solid materials. For accelerating growth, grains end up their migration at a finite radius, thus avoiding being accreted onto the central star.
description: 12 pages, 9 figures. Accepted for publication in MNRAS. v2: typos corrected
Quasinormal modes of charged dilaton black holes and their entropy spectra
Creators: name: Sakalli, I.
Publisher: name: arXiv
Year: 2013
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this study, we employ the scalar perturbations of the charged dilaton black hole (CDBH) found by Chan, Horne and Mann (CHM), and described with an action which emerges in the low-energy limit of the string theory. A CDBH is neither asymptotically flat (AF) nor non-asymptotically flat (NAF) spacetime. Depending on the value of its dilaton parameter "a", it has both Schwarzschild and linear dilaton black hole (LDBH) limits. We compute the complex frequencies of the quasinormal modes (QNMs) of the CDBH by considering small perturbations around its horizon. By using the highly damped QNMs in the process prescribed by Maggiore, we obtain the quantum entropy and area spectra of these BHs. Although the QNM frequencies are tuned by "a", we show that the quantum spectra do not depend on "a", and they are equally spaced. On the other hand, the obtained value of undetermined dimensionless constant ε is the double of Bekenstein's result. The possible reason of this discrepancy is also discussed.
description: 16 pages, no figure. Accepted for publication in MPLA
The growth of galactic bulges through mergers in LCDM haloes revisited. II. Morphological mix evolution
Creators: name: Avila-Reese, Vladimir
name: Zavala, Jesus
name: Lacerna, Ivan
Publisher: name: arXiv
Year: 2013
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The mass aggregation and merger histories of present-day distinct haloes selected from the cosmological Millennium Simulations I and II are mapped into stellar mass aggregation and galaxy merger histories of central galaxies by using empirical stellar-to-halo and stellar-to-gas mass relations. The growth of bulges driven by the galaxy mergers/interactions is calculated using dynamical prescriptions. The predicted bulge demographics at redshift z~0 is consistent with observations (Zavala+2012). Here we present the evolution of the morphological mix (traced by the bulge-to-total mass ratio, B/T) as a function of mass up to z=3. This mix remains qualitatively the same up to z~1: B/T<0.1 galaxies dominate at low masses, 0.10.45 at large masses. At z>1, the fractions of disc-dominated and bulgeless galaxies increase strongly, and by z~2 the era of pure disc galaxies is reached. Bulge-dominated galaxies acquire such a morphology, and most of their mass, following a downsizing trend. Since our results are consistent with most of the recent observational studies of the morphological mix at different redshifts, a LCDM-based scenario of merger-driven bulge assembly does not seem to face critical issues. However, if the stellar-to-halo mass relation changes too little with redshift, then some tensions with observations appear.
description: 16 pages, 11 figures. Accepted for publication in MNRAS. The method and the initial conditions are described in more detail. References added
Water masers map the complexity of mass loss from evolved stars
Creators: name: Richards, Anita M. S.
name: Asaki, Yoshiharu
name: Baudry, Alain
name: Cowie, Fraser
name: Decin, Leen
name: Etoka, Sandra
name: Gray, Malcolm D.
name: Herpin, Fabrice
name: Humpheys, Roberta
name: Montargès, Miguel
name: Pimpanuwat, Bannawit
name: Singh, Ambesh
name: Yates, Jeremy A.
name: Ziurys, Lucy
Publisher: name: Zenodo
Year: 2023
Subjects: evolved
stars
masers

description: Ten years of ALMA imaging of evolved star winds show that the rate, composition and dynamics of mass loss are changeable, inhomogenous and asymmetric. Water masers, in energy states from 200-6000 K,  trace the wind from the pulsation-dominated radio atmosphere, to acceleration through escape velocity, out to  regions where the molecules are photo-dissociated or freeze out. Dozens of transitions are accessible to ALMA, of which at least 7 have been imaged. Maser beaming allows the wind structure to be mapped from the radio atmosphere to hundreds of stellar radii (Rstar) at an order of magnitude higher resolution than is possible with thermal lines. Applying recently-developed models to the overlap or segregation of water (and OH and SiO)  maser transitions reveals the local density, temperature and other physical conditions on Rstar scales. Many water masers are concentrated in dense clumps whilst the less dense surrounding gas is traced by masers such as at 183-GHz and OH lines. These measurements provide input to constrain chemical and kinematic models of thermal lines and dust.
Only 22-GHz masers have been monitored long-term, showing variability linked to the stellar phase but too far from the star to be explained directly by  pulsation shocks, suggesting heating stimulates their collisional pumping. Large variations, sometimes localised, are  seen on other timescales, perhaps due to a companion, variable or episodic directed mass loss -- or simply cloud overlap.   High-resolution observations can reveal shocks, since shocked masers can appear almost as large as the emitting region, in contrast to the usual shrinking due to maser amplification. Shocks may explain the location of some high-energy transitions at tens Rstar, further than expected from the star.
We present studies of VY CMa (RSG) and R Hya (AGB). The former has been mapped in the most water transitions; the CSE of the latter bears the scars of a recent thermal pulse and suggested companion interaction.
Chimera States in a Two-Population Network of Coupled Pendulum-Like Elements
Creators: name: Bountis, Tassos
name: Kanas, Vasileios G.
name: Hizanidis, Johanne
name: Bezerianos, Anastasios
Publisher: name: arXiv
Year: 2013
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: More than a decade ago, a surprising coexistence of synchronous and asynchronous behavior called the chimera state was discovered in networks of nonlocally coupled identical phase oscillators. In later years, chimeras were found to occur in a variety of theoretical and experimental studies of chemical and optical systems, as well as models of neuron dynamics. In this work, we study two coupled populations of pendulum-like elements represented by phase oscillators with a second derivative term multiplied by a mass parameter $m$ and treat the first order derivative terms as dissipation with parameter $ε>0$. We first present numerical evidence showing that chimeras do exist in this system for small mass values $0
The Impact of Mindfulness-Based Interventions (MBIs) on Chinese Adolescent Mental Health: A Systematic Review and Meta-analysis
Creators: name: Shen, Sharon
Publisher: name: Stanford Digital Repository
Year: 2023
Subjects: subject: mindfulness-based interventions
subject: mental health outcomes
subject: Depression in adolescence
subject: Anxiety in adolescence
subject: China

description: This systematic review and meta-analysis examines the impact of mindfulness-based interventions (MBIs) on adolescent mental health outcomes in China. Through a comprehensive search of seven international and three Chinese electronic databases, a total of fifteen (15) eligible studies were included in the analysis. The pooled effect size of the included studies reveals a substantial reduction in depression and anxiety levels among adolescents who underwent MBIs (standardized mean difference = -1.00, 95% CI [-1.34, -0.66]). The strongest evidence of effectiveness exists for MBIs implemented in clinical settings (standardized mean difference = -1.50, 95% CI [-2.09, -0.91]) and among adolescents with pre-existing mental health disorders (standardized mean difference = -1.37, 95% CI [-1.82, -0.92]). Across different types of MBIs, Mindfulness-Based Stress Reduction (MBSR), mindfulness-based yoga or Tai Chi Chuan, and Mindfulness-Based Cognitive Therapy (MBCT) demonstrate significant effects on improving adolescent mental wellbeing. While the field of MBIs in China is still emerging, these findings make a significant contribution and provide valuable insights for the future design and implementation of mindfulness interventions for adolescents.
Growing dust grains in protoplanetary discs - II. The Radial drift barrier problem
Creators: name: Laibe, Guillaume
Publisher: name: arXiv
Year: 2013
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We aim to study the migration of growing dust grains in protoplanetary discs, where growth and migration are tightly coupled. This includes the crucial issue of the radial-drift barrier for growing dust grains. We therefore extend the study performed in Paper I, considering models for grain growth and grain dynamics where both the migration and growth rate depend on the grain size and the location in the disc. The parameter space of disc profiles and growth models is exhaustively explored. In doing so, interpretations for the grain motion found in numerical simulations are also provided. We find that a large number of cases is required to characterise entirely the grains radial motion, providing a large number of possible outcomes. Some of them lead dust particles to be accreted onto the central star and some of them don't. We find then that q<1 is required for discs to retain their growing particles, where q is the exponent of the radial temperature profile T(R) proportional to R^-q. Additionally, the initial dust-to gas ratio has to exceed a critical value for grains to pile up efficiently, thus avoiding being accreted onto the central star. Discs are also found to retain efficiently small dust grains regenerated by fragmentation. We show how those results are sensitive to the turbulent model considered. Even though some physical processes have been neglected, this study allows to sketch a scenario in which grains can survive the radial-drift barrier in protoplanetary discs as they grow.
description: 18 pages, 10 figures. Accepted for publication in MNRAS. v2: typos corrected
Higher Spin Currents in Wolf Space: Part I
Creators: name: Ahn, Changhyun
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: For the N=4 superconformal coset theory described by SU(N+2)/SU(N) (that contains a Wolf space) with N=3, the N=2 WZW affine current algebra with constraints is obtained. The 16 generators of the large N=4 linear superconformal algebra are described by those WZW affine currents explicitly. By factoring out four spin-1/2 currents and the spin-1 current from these 16 generators, the remaining 11 generators (spin-2 current, four spin-3/2 currents, and six spin-1 currents) corresponding to the large N=4 nonlinear superconformal algebra are obtained. Based on the recent work by Gaberdiel and Gopakumar on the large N=4 holography, the extra 16 currents, with spin contents (1, 3/2, 3/2, 2), (3/2, 2, 2, 5/2), (3/2, 2, 2, 5/2), and (2, 5/2, 5/2, 3) described in terms of N=2 multiplets, are obtained and realized by the WZW affine currents. As a first step towards N=4 W algebra (which is NOT known so far), the operator product expansions (OPEs) between the above 11 currents and these extra 16 higher spin currents are found explicitly. It turns out that the composite fields with definite U(1) charges, made of above (11+16) currents (which commute with the Wolf space subgroup SU(N=3) x SU(2) x U(1) currents), occur in the right hand sides of these OPEs.
description: 143 pages; Simplified the OPEs using compact notations, manifest SU(2) x SU(2) representations are given and to appear in JHEP
Development and validation of a panel of volatile biomarkers of airway eosinophilia in severe asthma.
Creators: name: Peltrini, Rosa
Publisher: name: University of Leicester
Year: 2022
Subjects: Uncategorized

description: Type 2 inflammation and airway eosinophilia have an incidence in 40-60% of severe asthmatics. Therefore, a number of biological therapies have been developed to target the type 2 inflammatory pathways involved in eosinophil activation, such as anti-IL5 and anti-IL5 receptor-α monoclonal antibodies. There is, therefore, the need to develop non-invasive biomarkers to assess airway eosinophilia, which seems to play an increasingly important role to improve severe asthmatics’ stratification for eosinophil targeted therapies This study aimed to develop a panel of volatile biomarkers of airway eosinophilia identifying, by GC-MS analysis and statistical modelling, volatile organic compounds (VOCs) in severe asthmatics’ sputum headspace samples, which were able to discriminate with a moderate accuracy eosinophil-enriched and non-eosinophil-enriched sputum headspaces. In order to optimise the headspace sampling method, the headspace background signal, generated within the sampling system in absence of sputum sample, was characterised, and its daily abundance variations were evaluated. Furthermore, the discovered panel of VOCs was validated in exhaled breath of severe asthmatics eligible for anti-IL5/Rα treatments by targeted GCxGC-FID/MS analysis. The statistical model developed showed a high accuracy to predict severe asthmatics’ one-year response to anti-IL5/Rα therapies. The in vitro selected VOCs were also validated in exhaled breath of exacerbating eosinophilic asthmatics and exacerbating non-eosinophilic asthmatics - whose classification was based on the blood eosinophil count threshold of 0.5x109/L - and healthy volunteers. The panel of VOCs revealed a high discriminatory accuracy among acute eosinophilic asthmatics, acute non-eosinophilic asthmatics and healthy volunteers, suggesting that the selected VOCs represent a promising, non-invasive clinical tool for asthma exacerbation prediction. A future challenge will be to identify the metabolic pathways, in activated eosinophil cultures, which may be involved in the origin of the selected VOCs, in order to confirm their inflammatory origin.
Developments in correlative and multimodal mass spectrometry imaging for comprehensive molecular mapping of biological tissues
Creators: name: Yang, Manxi
Publisher: name: Purdue University Graduate School
Year: 2024
Subjects: classificationCode: 310101
subject: Analytical biochemistry
classificationCode: 340101
subject: Analytical spectrometry

description: Mass spectrometry imaging (MSI) is a label-free approach for mapping the spatial distribution of individual molecules on sample surfaces. Multiple MSI techniques that utilize various ionization approaches have been developed for mapping of multiple classes of biomolecules, including lipids, metabolites, peptides, and glycans, on biological tissue sections. However, spatial mapping of individual intact proteoforms still remains challenging due to the relatively low extraction, ionization, ion transmission, and fragmentation efficiency. Nanospray desorption electrospray ionization (nano-DESI) is an ambient ionization technique that utilizes localized liquid extraction, enabling molecular mapping in tissue sections with high sensitivity and spatial resolution down to 10 µm. Relative quantification of individual molecules in tissue functional units can be performed by normalization of the signal intensity of the analytes to that of the internal standards integrated into the extraction solvent. Nano-DESI generates multiply charged ions of intact proteins, providing special opportunities for untargeted characterization and mapping of intact proteoforms directly from tissue samples. In this thesis, we developed a novel platform combining nano-DESI MSI with on-tissue tandem mass spectrometry (MS/MS) for spatial mapping of individual proteoforms on tissue sections. We demonstrated for the first time the differential expression of individual proteoforms with different post-translation modifications (PTMs) across tissue functional units, which provides unique insights into differences in biochemical pathways associated with different PTMs. Furthermore, we optimized sample preparation and the design of nano-DESI capillary probes and employed an oversampling strategy to improve the spatial resolution down to ~7 µm with improved sensitivity for proteoform mapping at the cellular-level spatial resolution. The developed methodology expands the molecular coverage and establishes nano-DESI MSI as a powerful tool for studying the state of diverse cell types. Moreover, we integrated the two different nano-DESI imaging workflows for metabolites/lipids and peptides/proteins into one platform to enable a correlative MSI approach for spatial multi-omics analysis. We applied this multimodal imaging approach to study the molecular signatures in specific cell types of healthy animal tissue samples and investigate the molecular pathology of diseased animal samples. The improvements in the nano-DESI MSI technique and its application provide new insights into the molecular phenotypes and the related cellular processes, opening up unique opportunities in clinical research.