cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
The impact of methylarginine metabolism on disease progression in idiopathic pulmonary fibrosis
Creators: name: Lota, Harpreet Kaur
Publisher: name: Imperial College London
Year: 2018

description: Idiopathic pulmonary fibrosis (IPF) is a complex, progressive and irreversible lung disease of unknown aetiology with a median survival of only three years following diagnosis. Signatures of increased nitric oxide (NO) and its generating enzyme, inducible nitric oxide synthase (iNOS), are observed in experimental models of idiopathic pulmonary fibrosis (IPF). Asymmetric dimethylarginine (ADMA) competitively inhibits iNOS, and is hydrolysed by dimethylarginine dimethylaminohydrolase (DDAH) 1 and 2. Previous evidence suggests that regulation of NO production via DDAH activity may play a role in IPF. Using both in vitro and human studies, this project investigated the relationship between the NO-ADMA-DDAH pathway and the progression of lung fibrosis; more specifically that variation in DDAH activity will impact on disease progression in IPF. The in vitro study aimed to identify the mechanistic pathways linking DDAH activity to lung fibrosis in an experimental model of transforming growth factor-β (TGF-β) mediated epithelial to mesenchymal transition (EMT) in a human alveolar epithelial cell line. DDAH2 and iNOS were induced during TGF-β mediated EMT, indicating that DDAH may play a role in the transition towards the fibrotic phenotype. The human study aimed to identify the impact of DDAH single nucleotide polymorphisms (SNPs) with a known functional effect on ADMA levels in a normal cohort on longitudinal lung function decline and survival in a cohort of IPF patients. The results indicated that DDAH1 variant rs530006 (associated with lower ADMA levels in a normal cohort) was significantly associated with accelerated lung function decline and mortality in the IPF cohort. DDAH2 SNPs were not associated with lung function decline or mortality in the IPF cohort. Neither DDAH1 or DDAH2 SNPs were associated with lung function decline in a large cohort of patients with systemic sclerosis associated interstitial lung disease (SSc-ILD), supportive of the genetic distinction that is emerging between the two fibrotic lung diseases. Overall, the evidence accumulated provides some novel insights into the potential role of DDAH in IPF. The complicated relationship between inherited genetic variants and environmental factors is a growing field in IPF, and DDAH biology may be one of the multiple pathways that leads to the fibrotic phenotype that we know as IPF.
Additional file 2 of Neighborhood disadvantage and 30-day readmission risk following Clostridioides difficile infection hospitalization
Creators: name: Scaria, Elizabeth
name: W. Ryan Powell
name: Birstler, Jen
name: Oguzhan Alagoz
name: Shirley, Daniel
name: Kind, Amy J. H.
name: Nasia Safdar
Publisher: name: figshare
Year: 2020
Subjects: subject: Medicine
subject: Biotechnology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: Sociology
subject: FOS: Sociology
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: Science Policy
subject: 111714 Mental Health
subject: FOS: Health sciences
subject: 110309 Infectious Diseases

description: Additional file 2: Supplementary Table 2. Sensitivity analysis of risk of readmission by ADI grouping for varying threshold.
Property screening of porous organic molecules
Creators: name: Miklitz, Marcin
Publisher: name: Imperial College London
Year: 2018

description: Porous organic molecules have internal pores readily occupied by gases, solvent or other guests. These molecules can form porous molecular materials with possible application in storage and separation. In this thesis, the properties of isolated porous organic molecules are used as a proxy to the bulk or in-solution applications. As a result, software was first developed for the automated and precise structural characterisation of porous organic molecules. This allows one to easily calculate window diameters to study the thermal window size fluctuations and predict guest diffusion in the bulk. A screening of previously reported porous organic molecules for the application of Xe/Kr separation allowed the most promising material, Noria, to be identified. This was possible with a combination of molecular modelling, electronic structure calculations and structural analysis using the developed software. The experimental Xe/Kr selectivity of Noria, not previously considered for this application, was shown to be comparable with the best performing porous materials. Next, eight synthetically realised porous organic cages were studied as possible C60 fullerene encapsulants. The relative orientation of the C60 fullerene in the pore was shown to have little to no effect on the binding energy and the encapsulation of the C60 during cage formation was determined as the likely mechanism of encapsulation. Lastly, a function-led material design approach was developed. An evolutionary algorithm was used to generate possible C60 encapsulants from a database of precursors. The resulting porous organic cages are structurally similar to some recently synthetically realised cages and some found in the literature. In summary, presented in this thesis is software, a methodology and results that can further advance the computational function-led materials discovery for specific applications.
The Active Jet in NGC 4258 and Its Associated Shocks
Creators: name: Perez‐Fournon, I.
name: Argon, A. L.
name: Nagar, N.
name: Wilson, A. S.
name: Dopita, M. A.
name: Cecil, G.
name: Greenhill, L. J.
name: DePree, C. G.
name: Moran, J. M.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2000

description: We present images and spectra of the active jet and anomalous arms on subparsec through kiloparsec scales in the LINER/Seyfert galaxy NGC 4258 (M106). New VLBA and multiconfiguration VLA images show that, on 0.3-300 pc scales, the jet in projection aligns with (1) the spin axis of the underlying accretion disk and (2) two radio hot spots 24'' S (840 pc) and 49'' N (1.7 kpc) from the nucleus. Hubble Space Telescope WFPC2 [N II] λ6583 + Hα images locate interactions between the jet and the interstellar medium (ISM). The most prominent is a pair of emission line arcs whose apices face away from the galaxy nucleus and envelop the leading edges of the radio hot spots. Ground-based (WHT) spectra with 2 Å resolution confirm that the gaseous kinematics and excitation of both arcs have the spatio-kinematic structure expected for jet working surfaces with a shock velocity 350 ± 100 km s-1. The north shock is oblique and may lie in a nuclear ionization cone. The south shock shows a detached, putative Mach disk. Models suggest that the S shock is a bow shock around a jet whose progress toward us through the galaxy ISM has stalled. This is notable because the inferred outflow axis is misaligned by ~65° (in three dimensions) with the spin axis of the accretion disk. Our emission line ratios and profiles diagnose the physical properties of the shocks, possible Mach disk, and thence the jets. The shocks lie at one end of a swath of kinematically disturbed gas that reaches back to the previously recognized spiral "anomalous arms," suggesting that they are linked dynamically by precession of the central engine; although claimed elsewhere to be bar shocks, the anomalous arms are probably a fossil record of changing jet activity in NGC 4258. Our results imply that the jet has recently moved a long way out of the plane of the galaxy. A deep Taurus Tunable Filter Hα image shows that discrete strands in the anomalous arms persist to galactocentric radii of at least 4' (>8 kpc), indicating an ongoing ISM interaction.
47 Tucanae: The Spectroscopic versus Color‐Magnitude Diagram Age Discrepancy
Creators: name: Arimoto, Nobuo
name: Salaris, Maurizio
name: Vazdekis, Alexandre
name: Rose, James
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2001

description: We investigate current problems in obtaining reliable ages for old stellar systems based on stellar population synthesis modeling of their integrated spectra. In particular, we address the large ages derived for the globular cluster 47 Tuc, which is at odds with its color-magnitude diagram (CMD) age. Using a new age indicator, Hγσ<130, which is particularly effective at breaking the degeneracy between age and metallicity, we confirm the discrepancy between the spectroscopic age and the CMD age of 47 Tuc, in that the spectroscopic age is much older. Nebular emission appears unlikely to be a source for weakening the observed Balmer lines. We then explore a number of key parameters affecting the temperature of turnoff stars, which are the main contributors to the Balmer lines for old metal-rich stellar populations. We find that α-enhanced isochrones with atomic diffusion included not only provide a good fit to the CMD of 47 Tuc but also lead to a spectroscopic age in better agreement with the CMD age.
Stealth Dark Matter: Dark scalar baryons through the Higgs portal
Creators: name: Appelquist, Thomas
name: Brower, Richard C.
name: Buchoff, Michael I.
name: Fleming, George T.
name: Jin, Xiao-Yong
name: Kiskis, Joe
name: Kribs, Graham D.
name: Neil, Ethan T.
name: Osborn, James C.
name: Rebbi, Claudio
name: Rinaldi, Enrico
name: Schaich, David
name: Schroeder, Chris
name: Syritsyn, Sergey
name: Vranas, Pavlos
name: Weinberg, Evan
name: Witzel, Oliver
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: We present a new model of "Stealth Dark Matter": a composite baryonic scalar of an $SU(N_D)$ strongly-coupled theory with even $N_D \geq 4$. All mass scales are technically natural, and dark matter stability is automatic without imposing an additional discrete or global symmetry. Constituent fermions transform in vector-like representations of the electroweak group that permit both electroweak-breaking and electroweak-preserving mass terms. This gives a tunable coupling of stealth dark matter to the Higgs boson independent of the dark matter mass itself. We specialize to $SU(4)$, and investigate the constraints on the model from dark meson decay, electroweak precision measurements, basic collider limits, and spin-independent direct detection scattering through Higgs exchange. We exploit our earlier lattice simulations that determined the composite spectrum as well as the effective Higgs coupling of stealth dark matter in order to place bounds from direct detection, excluding constituent fermions with dominantly electroweak-breaking masses. A lower bound on the dark baryon mass $m_B \gtrsim 300$ GeV is obtained from the indirect requirement that the lightest dark meson not be observable at LEP II. We briefly survey some intriguing properties of stealth dark matter that are worthy of future study, including: collider studies of dark meson production and decay; indirect detection signals from annihilation; relic abundance estimates for both symmetric and asymmetric mechanisms; and direct detection through electromagnetic polarizability, a detailed study of which will appear in a companion paper.
description: 15 pages, 3 figures, citations added, typos fixed, minor clarifications
RIDP__IEEE_CEM.pdf
Creators: name: Nanda, Ashish
name: Shah, Syed Wajid Ali
name: Jeong, Jongkil
name: Ram Mohan Doss, Robin
Publisher: name: figshare
Year: 2022
Subjects: subject: 89999 Information and Computing Sciences not elsewhere classified
subject: FOS: Computer and information sciences

description: Supplementary evidence on the following topics:
 Quality Requirements for Identity Evidence Strength of Methods Employed for Evidence Validation Strength of Methods Employed for Identity Verification Types of Neural-Networks used for generating Deepfakes Popular approaches for generating Replacement Deepfakes Popular approaches for generating Reenactment Deepfakes Popular approaches for detecting Deepfakes
Genetic mapping of metabolic biomarkers of cardiometabolic diseases
Creators: name: Rodriguez-Martinez, Andrea
Publisher: name: Imperial College London
Year: 2018

description: Cardiometabolic disorders (CMDs) are a major public health problem worldwide. The main goal of this thesis is to characterize the genetic architecture of CMD-related metabolites in a Lebanese cohort. In order to maximise the extraction of meaningful biological information from this dataset, an important part of this thesis focuses on the evaluation and subsequent improvement of the standard methods currently used for molecular epidemiology studies. First, I describe MetaboSignal, a novel network-based approach to explore the genetic regulation of the metabolome. Second, I comprehensively compare the recovery of metabolic information in the different 1H NMR strategies routinely used for metabolic profiling of plasma (standard 1D, spin-echo and JRES). Third, I describe a new method for dimensionality reduction of 1H NMR datasets prior to statistical modelling. Finally, I use all this methodological knowledge to search for molecular biomarkers of CMDs in a Lebanese population. Metabolome-wide association analyses identified a number of metabolites associated with CMDs, as well as several associations involving N-glycan units from acute-phase glycoproteins. Genetic mapping of these metabolites validated previously reported gene-metabolite associations, and revealed two novel loci associated with CMD-related metabolites. Collectively, this work contributes to the ongoing efforts to characterize the molecular mechanisms underlying complex human diseases.
Additional file 1 of Neighborhood disadvantage and 30-day readmission risk following Clostridioides difficile infection hospitalization
Creators: name: Scaria, Elizabeth
name: W. Ryan Powell
name: Birstler, Jen
name: Oguzhan Alagoz
name: Shirley, Daniel
name: Kind, Amy J. H.
name: Nasia Safdar
Publisher: name: figshare
Year: 2020
Subjects: subject: Medicine
subject: Biotechnology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: Sociology
subject: FOS: Sociology
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: Science Policy
subject: 111714 Mental Health
subject: FOS: Health sciences
subject: 110309 Infectious Diseases

description: Additional file 1: Supplementary Table 1. Odds of 30-day readmission for CDI patients by patient characteristic and ADI score national percentile.
The effects of atopy and asthma on in vivo human nasal responses to Toll-like receptor agonists
Creators: name: Jha, Akhilesh
Publisher: name: Imperial College London
Year: 2018

description: Acute respiratory viral infections cause significant morbidity and mortality, especially in vulnerable individuals, and it is important to study viral pathogenesis and the host immune response in humans. Toll-like receptors (TLRs) play a critical role in the detection of viral nucleic acids, and airway TLR receptors respond to nucleic acid patterns in the RNA viruses that cause respiratory infections. However, a reliable method of measuring mucosal innate immune responses to viral infections is lacking. TLR3 agonists (poly(I:C) and poly-ICLC) and the combined TLR7/8 agonist (resiquimod, R848) are synthetic analogues of double stranded RNA (dsRNA) and single stranded RNA (ssRNA) respectively. Nasal challenge with these TLR agonists was carried out, and serial sampling using nasosorption and nasal curettage was performed. Mucosal immune responses were measured and the effect of different host factors (e.g. asthma) on these responses was studied. Poly(I:C) and poly-ICLC were well tolerated but failed to induce significant and reliable nasal mucosal innate immune responses. R848 at a higher dose (10 µg/100 µL per nostril) induced significant mucosal interferon and cytokine responses but caused mild to moderate flu-like symptoms in three out of nine volunteers. A lower dose of R848 (0.02 µg/kg/100 µL, mean dose 1.5 µg/100 µL) was subsequently utilised in three groups of volunteers: healthy non-atopic (n=12), allergic rhinitis (n=12) and allergic asthma (n=11). This was well tolerated and induced significant release of nasal mucosal IFNs (IFN-α, IFN-γ), proinflammatory cytokines (TNF-α, IL-2, IL-12p70) and chemokines (CXCL10, CCL2, CCL3, CCL4 and CCL13) when compared to saline. Participants with allergic rhinitis and allergic asthma had similar IFN-α, CCL3 and CCL13 levels that were increased compared to healthy volunteers. In volunteers with atopy, baseline nasal mucosal gene expression of the anti-inflammatory secretoglobin SCGB1A1 had a strong negative correlation with subsequent innate immune activation by R848. Eight hours after R848 challenge, several mucosal IFN stimulated genes (ISGs) were upregulated (IFIT3, OAS2, IRF7, MX1, MYD88, DDX58 and STAT1) as well as SOCS1, TLR3, TLR7, KRT5 and CLEC4C, whilst IFNAR1 and ADGRG1 were downregulated. Volunteers with asthma had increased DDX58, MX1 and IFIT3 when compared to those with allergic rhinitis and healthy volunteers. This research has led to the successful development of a non-invasive and well tolerated method to induce and precisely measure nasal mucosal innate immune responses to the ssRNA analogue and TLR7/8 agonist R848, and this methodology has been used to demonstrate heightened innate immune activation in volunteers with allergic rhinitis and asthma. This technique can be extended to examine responses in a range of host conditions and diseases as well as to assess the adjuvant potential of R848 in conjunction with mucosal vaccines targeted against infection and cancer.
Chandra Observations and the Nature of the Anomalous Arms of NGC 4258 (M106)
Creators: name: Wilson, A. S.
name: Cecil, G.
name: Yang, Y.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2001

description: This paper presents high resolution X-ray observations with Chandra of NGC 4258 and infers the nature of the so called ``anomalous arms'' in this galaxy. The anomalous arms dominate the X-ray image; diffuse X-ray emission from the ``plateaux'' regions, seen in radio and H$\alpha$ imaging, is also found. X-ray spectra have been obtained at various locations along the anomalous arms and are well described by thermal (mekal) models with kT in the range 0.37 - 0.6 keV. The previously known kpc-scale radio jets are surrounded by cocoons of hot X-ray emitting gas for the first 350 pc of their length. The radio jets, seen in previous VLBA and VLA observations, propagate perpendicular to the compact nuclear gas disk (imaged in water vapor maser emission). The angle between the jets and the rotation axis of the galactic disk is 60$^{\circ}$. The jets shock the normal interstellar gas along the first 350 pc of their length, causing the hot, X-ray emitting cocoons noted above. At a height of z = 175 pc from the disk plane, the jets exit the normal gas disk and then propagate though the low density halo until they reach ``hot spots'' (at 870 pc and 1.7 kpc from the nucleus), which are seen in radio, optical line and X-ray emission. These jets must drive mass motions into the low density halo gas. This high velocity halo gas impacts on the dense galactic gas disk and shock heats it along and around a ``line of damage'', which is the projection of the jets onto the galactic gas disk as viewed down the galaxy disk rotation axis. However, because NGC 4258 is highly inclined ($i$ = 64$^{\circ}$), the ``line of damage'' projects on the sky in a different direction to the jets themselves. We calculate the expected p.a. of the ``line of damage'' on the sky and find that it coincides with the anomalous arms to within 2$^{\circ}$. (Abstract truncated). Comment: 12 pages plus 9 figures, to be published in the Astrophysical Journal, v560, nr 1, pt 1 (Oct 10, 2001 issue)
Direct Detection of Stealth Dark Matter through Electromagnetic Polarizability
Creators: name: Appelquist, Thomas
name: Berkowitz, Evan
name: Brower, Richard C.
name: Buchoff, Michael I.
name: Fleming, George T.
name: Jin, Xiao-Yong
name: Kiskis, Joe
name: Kribs, Graham D.
name: Neil, Ethan T.
name: Osborn, James C.
name: Rebbi, Claudio
name: Rinaldi, Enrico
name: Schaich, David
name: Schroeder, Chris
name: Syritsyn, Sergey
name: Vranas, Pavlos
name: Weinberg, Evan
name: Witzel, Oliver
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: We calculate the spin-independent scattering cross section for direct detection that results from the electromagnetic polarizability of a composite scalar baryon dark matter candidate -- "Stealth Dark Matter", that is based on a dark SU(4) confining gauge theory. In the nonrelativistic limit, electromagnetic polarizability proceeds through a dimension-7 interaction leading to a very small scattering cross section for dark matter with weak scale masses. This represents a lower bound on the scattering cross section for composite dark matter theories with electromagnetically charged constituents. We carry out lattice calculations of the polarizability for the lightest baryons in SU(3) and SU(4) gauge theories using the background field method on quenched configurations. We find the polarizabilities of SU(3) and SU(4) to be comparable (within about 50%) normalized to the baryon mass, which is suggestive for extensions to larger SU(N) groups. The resulting scattering cross sections with a xenon target are shown to be potentially detectable in the dark matter mass range of about 200-700 GeV, where the lower bound is from the existing LUX constraint while the upper bound is the coherent neutrino background. Significant uncertainties in the cross section remain due to the more complicated interaction of the polarizablity operator with nuclear structure, however the steep dependence on the dark matter mass, $1/m_B^6$, suggests the observable dark matter mass range is not appreciably modified. We briefly highlight collider searches for the mesons in the theory as well as the indirect astrophysical effects that may also provide excellent probes of stealth dark matter.
description: 6 pages, 2 figures, citations added, typos fixed, minor clarifications
Temporal control principles in cell cycle regulation
Creators: name: Carvalho Araújo, Ana Rita
Publisher: name: Imperial College London
Year: 2018

description: Cell division is characterized by a sequence of events by which a cell gives rise to two daughter cells. In order to maintain the integrity of the genome, cell growth, chromosome duplication and chromosome segregation must be coordinated in a manner that ensures the faithful transmission of hereditary information from one generation to the next. Mis- segregation of chromosomes, chromosomal abnormalities and de-regulation of cell division timing are well known hallmarks of cancer. Even though the molecular machinery that drives cell division is the same in all tissues cell cycle duration in mammalian cells varies for different cell types: embryonic cells divide faster than differentiated cells, for example. In addition, classical experiments have highlighted a high level of variability in cell cycle duration even within the same cell type. Understanding temporal control of cell division and, in particular, how the same cell cycle regulators control differences in cell cycle length is a fundamental question in cell and developmental biology. To address this question, a multidisciplinary approach combining live cell imaging of human cells and mathematical modelling was used. It was found that duration of mitosis is strictly dependent on feedback regulation networks that control mitotic entry. Positive feedback within these networks ensures that mitosis is short and temporally insulated from upstream cell cycle events. Modulation of regulatory feedbacks was also found to allow fine-tuning of cell division frequency, showing once more the importance of feedback control in temporal regulation of cell division. The work presented in this thesis suggests that understanding cell cycle dynamics at a single cell level provides a powerful way to derive control principles in cell cycle regulation. Moreover, combining experimental approaches with computational analysis allows a quantitative understanding of temporal control in cell division at a single cell level. This is likely to lead to transformative insights into cell cycle in health and disease states.
Thermal Equilibration of 26 Al
Creators: name: Champagne, A. E.
name: Runkle, R. C.
name: Engel, J.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2001

description: In astrophysical environments, the long-lived (t1/2 = 0.72 Myr) ground state of 26Al can communicate with its short-lived (t1/2 = 6.35 s) first excited state through thermal excitations. The result is that the astrophysical half-life for 26Al can be much shorter than the laboratory value, which can have an impact on the amount of 26Al produced at high temperatures. We have reexamined the equilibration process using the results of new calculations of some of the key transition rates. In addition, we discuss a simple way of describing the behavior of 26Al in a stellar plasma and use this to better define the conditions where equilibration is expected to be important. Finally, we present a series of network calculations to show how the interplay between the timescale for equilibration versus that for nuclear reactions will govern the evolution of 26Al.
The One-Dimensional Line Scheme of a Certain Family of Quantum ${\mathbb P}^3$s
Creators: name: Chandler, Richard G.
name: Vancliff, Michaela
Publisher: name: arXiv
Year: 2015
Subjects: subject: Rings and Algebras (math.RA)
subject: FOS: Mathematics
subject: 14A22, 16S37, 16S38

description: A quantum ${\mathbb P}^3$ is a noncommutative analogue of a polynomial ring on four variables, and, herein, it is taken to be a regular algebra of global dimension four. It is well known that if a generic quadratic quantum ${\mathbb P}^3$ exists, then it has a point scheme consisting of exactly twenty distinct points and a one-dimensional line scheme. In this article, we compute the line scheme of a family of algebras whose generic member is a candidate for a generic quadratic quantum ${\mathbb P}^3$. We find that, as a closed subscheme of ${\mathbb P}^5$, the line scheme of the generic member is the union of seven curves; namely, a nonplanar elliptic curve in a ${\mathbb P}^3$, four planar elliptic curves and two nonsingular conics.
Derivative expansion for the electromagnetic and Neumann Casimir effects in $2+1$ dimensions with imperfect mirrors
Creators: name: Fosco, C. D.
name: Lombardo, F. C.
name: Mazzitelli, F. D.
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We calculate the Casimir interaction energy in $d=2$ spatial dimensions between two (zero-width) mirrors, one flat, and the other slightly curved, upon which {\em imperfect\/} conductor boundary conditions are imposed for an Electromagnetic (EM) field. Our main result is a second-order Derivative Expansion (DE) approximation for the Casimir energy, which is studied in different interesting limits. In particular, we focus on the emergence of a non-analyticity beyond the leading-order term in the DE, when approaching the limit of perfectly-conducting mirrors. We also show that the system considered is equivalent to a dual one, consisting of a massless real scalar field satisfying imperfect Neumann conditions (on the very same boundaries). Therefore, the results obtained for the EM field hold also true for the scalar field model
Temporal decay of Neel order in the one-dimensional Fermi-Hubbard model
Creators: name: Bauer, A.
name: Dorfner, F.
name: Heidrich-Meisner, F.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Motivated by recent experiments with ultra-cold quantum gases in optical lattices we study the decay of the staggered moment in the one-dimensional Fermi-Hubbard model starting from a perfect Neel state using exact diagonalization and the iTEBD method. This extends previous work in which the same problem has been addressed for pure spin Hamiltonians. As a main result, we show that the relaxation dynamics of the double occupancy and of the staggered moment are different. The former is controlled by the nearest-neighbor tunneling rate while the latter is much slower and strongly dependent on the interaction strength, indicating that spin excitations are important. This difference in characteristic energy scales for the fast charge dynamics and the much slower spin dynamics is also reflected in the real-time evolution of nearest-neighbor density and spin correlations. A very interesting time dependence emerges in the von Neumann entropy, which at short times increases linearly with a slope proportional to the tunneling matrix element while the long-time growth of entanglement is controlled by spin excitations. Our predictions for the different relaxation dynamics of the staggered moment and the double occupancy should be observable in state-of-the art optical lattice experiments. We further compare time averages of the double occupancy to both the expectation values in the canonical and diagonal ensemble, which quantitatively disagree with each other on finite systems. We relate the question of thermalization to the eigenstate thermalization hypothesis.
description: 9 pages, 9 figures
Approach of background metric expansion to a new metric ansatz for gauged and ungauged Kaluza-Klein supergravity black holes
Creators: name: Wu, Shuang-Qing
name: Wang, He
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: In a previous paper [S.Q. Wu, Phys. Rev. D 83, 121502(R) (2011)], a new kind of metric ansatz was found to fairly describe all already known black hole solutions in the ungauged Kaluza-Klein (KK) supergravity theories. That metric ansatz somewhat resembles to the famous Kerr-Schild (KS) form, but it is different from the KS one in two distinct aspects. That is, apart from a global conformal factor, the metric ansatz can be written as a vacuum background spacetime plus a "perturbation" modification term, the latter of which is associated with a timelike geodesic vector field rather than a null geodesic congruence in the usual KS ansatz. In this paper, we shall study this novel metric ansatz in detail, aiming at achieving some inspiration as to the construction of rotating charged AdS black holes with multiple charges in other gauged supergravity theories. In order to investigate the metric properties of the general KK-AdS solutions, in this paper we devise a new effective method, dubbed the background metric expansion method, which can be thought of as a generalization of the perturbation expansion method, to deal with the Lagrangian and all equations of motion. In addition to two previously known conditions, namely the timelike and geodesic properties of the vector, we get the three additional constraints via contracting the Maxwell and Einstein equations once or twice with this timelike geodesic vector. In particular, we find that these are a simple set of sufficient conditions to determine the vector and the dilaton scalar around the background metric, which is helpful in obtaining new exact solutions. With these five simplified equations in hand, we rederive the general rotating charged KK-(A)dS black hole solutions with spherical horizon topology and obtain new solutions with planar topology in all dimensions.
description: 9 pages, Revtex4.cls, version mathched with the published paper
The application of bayesian and frequentist regularization and variable selection methods for the prediction of asthma in later childhood
Creators: name: Colicino, Silvia
Publisher: name: Imperial College London
Year: 2019

description: Asthma is a global health problem and among the most common chronic conditions in childhood. Several models were proposed to predict asthma in children, but their reproducibility in external populations was limited and none was developed to predict asthma in adolescence. I conducted a systematic review of asthma predictive models validated in external populations; validation studies showed poorer predictive performances than development studies. I developed predictive models for asthma between 15 and 20 years, using data from the Study Team for Early Life Asthma Research (STELAR) consortium of five UK asthma cohorts. For one of these cohorts, the Ashford study, I developed an questionnaire to collect follow-up information when study subjects were age 20 years. I harmonised 41 variables across the STELAR cohorts, 39 of which were used as candidate predictors to develop predictive models, while the others were used to define asthma at 15–20 years. Asthma at that age was defined as positive responses to ‘current wheezing’ and ‘asthma medications in the last year’.Two of the five STELAR cohorts (development data) were combined to develop predictive models using stepwise regression and frequentist, Bayesian and empirical Bayes regularization models. The remaining cohorts (validation data) were used to assess predictive performance using discrimination and accuracy measures. Analyses were performed in two populations - all children and a subgroup with reported wheezing between two and five years (high-risk population). Sex, eczema, sensitization to house dust mite and doctor’s diagnosis of asthma in early childhood (4-7 years) were identified as asthma predictors at 15-20 years in both populations. Additional predictors in the general population included early wheezing symptoms and parental allergies, while in the high-risk population maternal allergies and pet in the house at one year were important for asthma prediction in adolescence. Sensitivity was higher in the general population, whereas positive predictive value was higher in the high-risk population. Although accuracy was good in both populations, the predictive ability of the models developed was limited.
Population Synthesis in the Blue. I. Synthesis of the Integrated Spectrum of 47 Tucanae from Its Color‐Magnitude Diagram
Creators: name: Schiavon, Ricardo
name: Faber, S. M.
name: Rose, James
name: Castilho, Bruno
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2002

description: We perform an empirical synthesis of the blue integrated spectrum of the metal-rich globular cluster 47 Tucanae, based directly on the color-magnitude diagram of the cluster coupled to a moderately high resolution spectral library. Freed from any significant dependence on theory, we are able to perform a fundamental test of the adequacy of the spectral library and its associated stellar parameters. Excellent fits are achieved for almost all absorption-line indices studied, provided the computations are corrected for two limitations of the spectral library, namely, the lack of a representative set of metal-poor giants and the absence of CN-strong stars. The latter effect is corrected by means of spectrum synthesis from model photospheres, considering the abundance pattern of CN-strong and CN-normal stars. We also need to perform a slight correction of the metallicity of the cluster (by -0.05 dex in relation to the standard value [Fe/H] = -0.7) in order to match the metal line index measurements in the cluster spectrum. After these relatively small adjustments, the overall spectral agreement is good. Good fits are achieved for Hβ, Hγ, Mg b, , Ca λ4227, and Fe λ4383, and only HδF is overpredicted. Thus, ages inferred from HδF are slightly older than the ages based on the other Balmer lines, by ~3 Gyr. The success of this exercise suggests that previous failures to synthesize the spectrum of 47 Tuc must have arisen from inadequacies in the theoretical evolutionary isochrones and/or luminosity functions. Such a possibility is considered in a companion paper.
Additional file 3 of Neighborhood disadvantage and 30-day readmission risk following Clostridioides difficile infection hospitalization
Creators: name: Scaria, Elizabeth
name: W. Ryan Powell
name: Birstler, Jen
name: Oguzhan Alagoz
name: Shirley, Daniel
name: Kind, Amy J. H.
name: Nasia Safdar
Publisher: name: figshare
Year: 2020
Subjects: subject: Medicine
subject: Biotechnology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: Sociology
subject: FOS: Sociology
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: Science Policy
subject: 111714 Mental Health
subject: FOS: Health sciences
subject: 110309 Infectious Diseases

description: Additional file 3: Supplementary Table 3. Odds of 30-day rehospitalization by subgroup.
Putting artificial intelligence into wearable human-machine interfaces – towards a generic, self-improving controller
Creators: name: Admiraal, Marcel
Publisher: name: Imperial College London
Year: 2019

description: The standard approach to creating a machine learning based controller is to provide users with a number of gestures that they need to make; record multiple instances of each gesture using specific sensors; extract the relevant sensor data and pass it through a supervised learning algorithm until the algorithm can successfully identify the gestures; map each gesture to a control signal that performs a desired outcome. This approach is both inflexible and time consuming. The primary contribution of this research was to investigate a new approach to putting artificial intelligence into wearable human-machine interfaces by creating a Generic, Self-Improving Controller. It was shown to learn two user-defined static gestures with an accuracy of 100% in less than 10 samples per gesture; three in less than 20 samples per gesture; and four in less than 35 samples per gesture. Pre-defined dynamic gestures were more difficult to learn. It learnt two with an accuracy of 90% in less than 6,000 samples per gesture; and four with an accuracy of 70% after 50,000 samples per gesture. The research has resulted in a number of additional contributions: • The creation of a source-independent hardware data capture, processing, fusion and storage tool for standardising the capture and storage of historical copies of data captured from multiple different sensors. • An improved Attitude and Heading Reference System (AHRS) algorithm for calculating orientation quaternions that is five orders of magnitude more precise. • The reformulation of the regularised TD learning algorithm; the reformulation of the TD learning algorithm applied the artificial neural network back-propagation algorithm; and the combination of the reformulations into a new, regularised TD learning algorithm applied to the artificial neural network back-propagation algorithm. • The creation of a Generic, Self-Improving Predictor that can use different learning algorithms and a Flexible Artificial Neural Network.
Chandra Detection of a Pulsar Wind Nebula Associated with Supernova Remnant 3C 396
Creators: name: Olbert, C. M.
name: Safi-Harb, S.
name: Reynolds, S. P.
name: Keohane, J. W.
name: Arnaud, K. A.
name: Dyer, K. K.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2003

description: We present a 100 ks observation of the Galactic supernova remnant 3C 396 (G39.2-0.3) with the Chandra X-Ray Observatory that we compare with a 20 cm map of the remnant from the Very Large Array. In the Chandra images, a nonthermal nebula containing an embedded pointlike source is apparent near the center of the remnant that we interpret as a synchrotron pulsar wind nebula surrounding a yet undetected pulsar. From the 2-10 keV spectrum for the nebula [NH = (5.3 ± 0.9) × 1022 cm-2, Γ = 1.5 ± 0.3] we derive an unabsorbed X-ray flux of SX = 1.62 × 10-12 ergs cm-2 s-1, and from this we estimate the spin-down power of the neutron star to be = 7.2 × 1036 ergs s-1. The central nebula is morphologically complex, showing bent, extended structure. The radio and X-ray shells of the remnant correlate poorly on large scales, particularly on the eastern half of the remnant, which appears very faint in X-ray images. At both radio and X-ray wavelengths, the western half of the remnant is substantially brighter than the eastern half.
Superconductivity-Induced Changes in Density-Density Correlation Function Enabled by Umklapp Processes
Creators: name: Lee, Wei-Cheng
Publisher: name: arXiv
Year: 2015
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Motivated by the mid-infrared scenario for high-temperature superconductivity proposed by Leggett, the effects of Umklapp processes on the density-density correlation function in the presence of long-range Coulomb interaction have been investigated on a microscopic model. We show that because Umklapp processes enable scatterings that conserve total momentum only up to $n\vec{K}$, where $n$ is an integer and $\vec{K}$ is the reciprocal wave vector, significant amounts of spectral weight in the plasmonic excitations at long wavelength are transferred into lower frequency around mid-infrared regime. We further find that regardless of the gap symmetry, superconductivity generally suppresses the Umklapp scatterings due to the formation of the electron pairing. This suppression is unique for the superconductivity due to the interplay between electron pairing and the odd parity of the matrix elements associated with Umklapp channels, which usually does not occur in other known competing orders. Specific predictions for the experimental signatures in optical conductivity and electron energy loss spectroscopy (EELS) will be discussed.
description: 8 pages, 6 figures, accepted for publication in Phys. Rev. B
Electronic structure of oxide materials for photoelectrochemistry
Creators: name: Blumenthal, Lars
Publisher: name: Imperial College London
Year: 2019

description: To achieve climate protection goals set out by national governments and the United Nations, it is paramount to reduce society’s dependence on fossil fuels and to introduce more sustainable energy solutions. Furthermore, to not only protect our climate but the natural environment in general, it is necessary to reduce humanity’s waste production and to turn waste into a resource wherever possible. The solutions to both of these ambitions will heavily rely on new chemical processes being discovered and upscaled. Thus, with catalysis and photochemistry at its heart, the challenge to build a greener and more sustainable future is largely a materials discovery and design problem. In this work, I introduce a new way of aligning the electronic energy levels of semiconductors with respect to redox potentials which might facilitate in silico screening studies of materials suitable for photoelectrochemistry. In particular, I demonstrate how continuum solvation models can be used to replace computationally expensive atomistic descriptions of water when describing an electrode-electrolyte interface. I tested this approach on rutile (TiO2) showing that, when combined with a description of rutile’s electronic structure within many-body perturbation theory, the proposed alignment procedure yields the correct positioning of rutile’s band edges on the standard hydrogen electrode scale. My investigation surfaced and explained important differences between atomistic and continuum solvation models when describing the electric potential across interfaces. Furthermore, I present a detailed study of the electronic structure of osmium dioxide (OsO2) near its Fermi level. OsO2 is closely related to important catalysts such as IrO2 and RuO2, which also crystallise in the rutile structure. Specifically, by collaborating with colleagues specialised in experimental photoelectron spectroscopy (PES), we highlight the importance of computational insights for the correct interpretation of PES spectra. By going beyond a simple comparison between the experimentally measured PES spectrum and the computed single-particle electronic density of states, we reveal that the spectrum of OsO2 features a rare low-energy bulk plasmon satellite.
Observational signatures of the theories beyond Horndeski
Creators: name: De Felice, Antonio
name: Koyama, Kazuya
name: Tsujikawa, Shinji
Publisher: name: arXiv
Year: 2015
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In the approach of the effective field theory of modified gravity, we derive the equations of motion for linear perturbations in the presence of a barotropic perfect fluid on the flat isotropic cosmological background. In a simple version of Gleyzes-Langlois-Piazza-Vernizzi (GLPV) theories, which is the minimum extension of Horndeski theories, we show that a slight deviation of the tensor propagation speed squared $c_{\rm t}^2$ from 1 generally leads to the large modification to the propagation speed squared $c_{\rm s}^2$ of a scalar degree of freedom $ϕ$. This problem persists whenever the kinetic energy $ρ_X$ of the field $ϕ$ is much smaller than the background energy density $ρ_m$, which is the case for most of dark energy models in the asymptotic past. Since the scaling solution characterized by the constant ratio $ρ_X/ρ_m$ is one way out for avoiding such a problem, we study the evolution of perturbations for a scaling dark energy model in the framework of GLPV theories in the Jordan frame. Provided the oscillating mode of scalar perturbations is fine-tuned so that it is initially suppressed, the anisotropic parameter $η=-Φ/Ψ$ between the two gravitational potentials $Ψ$ and $Φ$ significantly deviates from 1 for $c_{\rm t}^2$ away from 1. For other general initial conditions, the deviation of $c_{\rm t}^2$ from 1 gives rise to the large oscillation of $Ψ$ with the frequency related to $c_{\rm s}^2$. In both cases, the model can leave distinct imprints for the observations of CMB and weak lensing.
description: 20 pages, 4 figures, published in JCAP