cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Sample-Efficient Deep Reinforcement Learning for Continuous Control
Creators: name: Gu, Shixiang
Publisher: name: Apollo - University of Cambridge Repository
Year: 2019
Subjects: Reinforcement Learning
Continuous Control
Robotics
Deep Learning
Machine Learning
Model-based Planning
Model-free Reinforcement Learning

description: Reinforcement learning (RL) is a powerful, generic approach to discovering optimal policies in complex sequential decision-making problems. Recently, with flexible function approximators such as neural networks, RL has greatly expanded its realm of applications, from playing computer games with pixel inputs, to mastering the game of Go, to learning parkour movements by simulated humanoids. However, the common RL approaches are known to be sample intensive, making them difficult to be applied to real-world problems such as robotics. This thesis makes several contributions toward developing RL algorithms for learning in the wild, where sample-efficiency and stability are critical. The key contributions include Normalized Advantage Functions (NAF), extending Q-learning for continuous action problems; Interpolated Policy Gradient (IPG), unifying prior policy gradient algorithm variants through theoretical analyses on bias and variance; and Temporal Difference Models (TDM), interpreting a parameterized Q-function as a generalized dynamics model for novel temporally abstracted model-based planning. Importantly, this thesis highlights that these algorithms can be seen as bridging gaps between branches of RL – model-based with modelfree, and on-policy with off-policy. The proposed algorithms not only achieve substantial improvements over the prior approaches, but also provide novel perspectives on how to mix different branches of RL effectively to gain the best of both worlds. NAF has subsequently been shown to be able to train two 7-DoF robot arms to open doors using only 2.5 hours of real-world experience, making it one of the first demonstrations of deep RL approaches on real robots.
description: - Cambridge-Tuebingen PhD Fellowship in Machine Learning - Google Focused Research Award - NSERC
CityLearn: Diverse Real-World Environments for Sample-Efficient Navigation Policy Learning
Creators: name: Chancán, Marvin
name: Milford, Michael
Publisher: name: arXiv
Year: 2019
Subjects: subject: Robotics (cs.RO)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Visual navigation tasks in real-world environments often require both self-motion and place recognition feedback. While deep reinforcement learning has shown success in solving these perception and decision-making problems in an end-to-end manner, these algorithms require large amounts of experience to learn navigation policies from high-dimensional data, which is generally impractical for real robots due to sample complexity. In this paper, we address these problems with two main contributions. We first leverage place recognition and deep learning techniques combined with goal destination feedback to generate compact, bimodal image representations that can then be used to effectively learn control policies from a small amount of experience. Second, we present an interactive framework, CityLearn, that enables for the first time training and deployment of navigation algorithms across city-sized, realistic environments with extreme visual appearance changes. CityLearn features more than 10 benchmark datasets, often used in visual place recognition and autonomous driving research, including over 100 recorded traversals across 60 cities around the world. We evaluate our approach on two CityLearn environments, training our navigation policy on a single traversal. Results show our method can be over 2 orders of magnitude faster than when using raw images, and can also generalize across extreme visual changes including day to night and summer to winter transitions.
description: Preprint version of article accepted to ICRA 2020
Dōsen Dai Nihon kokusaizu. Ge
銅鐫大日本國細圖 下
Creators: name: Matsuda, Ryokuzan.
Publisher: name: Kyōto : Katsumura Jiemon and twenty-one others
Year: 2021

description: Volume 1 begins with maps of Japan and the world, followed by maps of individual provinces. Roads, towns, castles and provinces indicated. Gengendō is the shop name of Matsuda Ryokuzan.
Loop, String, and Hadron Dynamics in SU(2) Hamiltonian Lattice Gauge Theories
Creators: name: Raychowdhury, Indrakshi
name: Stryker, Jesse R.
Publisher: name: arXiv
Year: 2019
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The question of how to efficiently formulate Hamiltonian gauge theories is experiencing renewed interest due to advances in building quantum simulation platforms. We introduce a reformulation of an SU(2) Hamiltonian lattice gauge theory---a loop-string-hadron (LSH) formulation---that describes dynamics directly in terms of its loop, string, and hadron degrees of freedom, while alleviating several disadvantages of quantumly simulating the Kogut-Susskind formulation. This LSH formulation transcends the local loop formulation of $d+1$-dimensional lattice gauge theories by incorporating staggered quarks, furnishing the algebra of gauge-singlet operators, and being used to reconstruct dynamics between states that have Gauss's law built in to them. LSH operators are then factored into products of "normalized" ladder operators and diagonal matrices, priming them for classical or quantum information processing. Self-contained expressions of the Hamiltonian are given up to $d=3$. The LSH formalism makes little use of structures specific to SU(2) and its conceptual clarity makes it an attractive approach to apply to other non-Abelian groups like SU(3).
description: v2: Corrections made in Eqs. (37a,43b,54) to signs/normalizations, and propagated [notably to Tables (I,II,IV) and Eqs. (65,76,91)]. References removed/added. Other minor edits throughout. 26 pages, 9 figures, 6 tables
Current hysteresis and memory effect in a molecular quantum dot with strong electron-vibron interaction
Creators: name: Alexandrov, A. S.
name: Bratkovsky, A. M.
Publisher: name: arXiv
Year: 2002
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Theory of current hysteresis for tunneling through a molecular quantum dot (MQD) with strong electron-vibron interactions and attractive electron-electron correlations is developed. The dot is modeled as a d-fold degenerate energy level weakly coupled to the leads. The effective attractive interaction between polarons in the dot results in a "switching" phenomenon in the current-voltage characteristics when d>2, in agreement with the results for the phenomenological negative-U model. The degenerate MQD with strong electron-vibron coupling has two stable current states in certain interval of the bias voltage below some critical temperature.
description: 8 pages, 4 figures
title: Acceptance of Climate-Oriented Policy Measures in Times of the COVID-19 crisis
title: MAGKS - Joint Discussion Paper Series in Economics
Creators: name: Engler, Daniel
name: Groh, Elke D.
name: Gutsche, Gunnar
name: Ziegler, Andreas
Publisher: name: Philipps-Universität Marburg
Year: 2020
Subjects: climate policy measures
climate-oriented economic stimulus programs
Economics
Wirtschaft
multivariate probit models
COVID-19 crisis
acceptance

description: Based on data from a representative survey among citizens in Germany during the peak of the COVID-19 crisis, this paper empirically examines the acceptance of climate-oriented economic stimulus programs and several further climate policy measures. Our descriptive analysis shows no general lower acceptance of climate policy measures compared to the time before the crisis. However, the econometric analysis reveals that individuals with higher negative emotions towards the crisis are significantly less supportive of at least some climate-oriented policy measures. Economic concerns are of particular relevance. For example, a perceived deterioration of the general economic situation due to the COVID-19 crisis has a significantly negative effect on the acceptance of climate-oriented economic stimulus programs. Concerns about the own personal economic and financial situation due to the crisis are significantly negatively correlated with the support of climate-oriented policy measures that directly lead to higher costs in daily life. Besides the relevance of this perceived self-interest, our estimation results also highlight the relevance of social aspects since individuals with a social policy identification are significantly more likely to agree with climate-oriented policy measures that are also financially beneficial for socially de-prived groups, but significantly less likely to support measures that are financially unfa-vorable for them. We discuss several climate policy implications. For example, our estima-tion results suggest that successful climate policy should, especially in times of the COVID-19 crisis, also be socially oriented and consider distribution effects, for example, through financial compensations for costly measures like taxes.
Towards Sample-efficient Overparameterized Meta-learning
Creators: name: Sun, Yue
name: Narang, Adhyyan
name: Gulluk, Halil Ibrahim
name: Oymak, Samet
name: Fazel, Maryam
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: An overarching goal in machine learning is to build a generalizable model with few samples. To this end, overparameterization has been the subject of immense interest to explain the generalization ability of deep nets even when the size of the dataset is smaller than that of the model. While the prior literature focuses on the classical supervised setting, this paper aims to demystify overparameterization for meta-learning. Here we have a sequence of linear-regression tasks and we ask: (1) Given earlier tasks, what is the optimal linear representation of features for a new downstream task? and (2) How many samples do we need to build this representation? This work shows that surprisingly, overparameterization arises as a natural answer to these fundamental meta-learning questions. Specifically, for (1), we first show that learning the optimal representation coincides with the problem of designing a task-aware regularization to promote inductive bias. We leverage this inductive bias to explain how the downstream task actually benefits from overparameterization, in contrast to prior works on few-shot learning. For (2), we develop a theory to explain how feature covariance can implicitly help reduce the sample complexity well below the degrees of freedom and lead to small estimation error. We then integrate these findings to obtain an overall performance guarantee for our meta-learning algorithm. Numerical experiments on real and synthetic data verify our insights on overparameterized meta-learning.
Covariance and Fisher information in quantum mechanics
Creators: name: Petz, Denes
Publisher: name: arXiv
Year: 2001
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Variance and Fisher information are ingredients of the Cramer-Rao inequality. We regard Fisher information as a Riemannian metric on a quantum statistical manifold and choose monotonicity under coarse graining as the fundamental property of variance and Fisher information. In this approach we show that there is a kind of dual one-to-one correspondence between the candidates of the two concepts. We emphasis that Fisher informations are obtained from relative entropies as contrast functions on the state space and argue that the scalar curvature might be interpreted as an uncertainty density on a statistical manifold.
description: LATEX
title: Lying and Mistrust in the Continuous Deception Game
title: MAGKS - Joint Discussion Paper Series in Economics
Creators: name: Beck, Tobias
Publisher: name: Philipps-Universität Marburg
Year: 2020
Subjects: Honesty
Asymmetric information
Economics
Wirtschaft
Experimental Design
Investments
Lies
Mistrust
Deception Game

description: I present a novel experimental design to measure lying and mistrust as continuous variables on an individual level. My experiment is a sender-receiver game framed as an investment game. It features two players: firstly, an advisor with complete information (i.e., the sender) who is incentivized to lie about the true value of an optimal investment and, secondly, an investor with incomplete information (i.e., the receiver) who is incentivized to invest optimally and therefore must rely on the alleged optimum reported by the advisor. The extents of lying and mistrust are both measured on continuous scales. This allows observing more differentiated behavior and therefore enables testing of more sophisticated theoretical predictions. I find that the senders lie by overstating the true value of the optimum to an average extent of about 148%, while the receivers suspect them to do so by only 56%. The senders seldomly lie to the fullest possible extent as they correctly expect the receivers to disproportionally mistrust lies of such a high extent. This indicates that people make strategic considerations about their potential to manipulate others when lying. In line with this, I discover that lying and mistrusting behavior can be predicted by first-order beliefs about the other player. Consistent with previous studies, my findings support the conjecture that lying costs increase with the extent of lying. In addition, I provide evidence for some endogenous preference for trust. Both players’ behaviors and beliefs are consistent over time. Moreover, my ex ante classification of both players’ strategy sets is consistent with their ex post self-assessment of their own behavior within the experiment.
Patterns of chiral symmetry breaking and a candidate for a C-theorem in four dimensions
Creators: name: Levinsen, Jesper
Publisher: name: arXiv
Year: 2001
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We test a candidate for a four-dimensional C-function. This is done by considering all asymptotically free, vectorlike gauge theories with N_f flavors and fermions in arbitrary representations of any simple Lie group. Assuming spontaneous breaking of chiral symmetry in the infrared limit and that the value of the C-function in this limit is determined by the number of Goldstone bosons, we find that only in the case of a theory with two colors and fermions in one single pseudo-real representation of SU(2) the C-theorem seems to be violated. Conversely, this might also be a sign of new constraints, restricting the number of flavors consistent with spontaneous chiral symmetry breaking. For all other groups and representations we find that this candidate C-function decreases along the renormalization group flow.
description: RevTeX 5 pages
Polymer Nanoreactors Shield Perovskite Nanocrystals from Degradation
Creators: name: Hintermayr, Verena A.
name: Lampe, Carola
name: Löw, Maximilian
name: Roemer, Janina
name: Vanderlinden, Willem
name: Gramlich, Moritz
name: Böhm, Anton X.
name: Sattler, Cornelia
name: Nickel, Bert
name: Lohmüller, Theobald
name: Urban, Alexander S.
Publisher: name: arXiv
Year: 2019
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: Halide perovskite nanocrystals (NCs) have shown impressive advances, exhibiting optical properties that outpace conventional semiconductor NCs, such as near-unity quantum yields and ultrafast radiative decay rates. Nevertheless, the NCs suffer even more from stability problems at ambient conditions and due to moisture than their bulk counterparts. Herein, we report a strategy of employing polymer micelles as nanoreactors for the synthesis of methylammonium lead trihalide perovskite NCs. Encapsulated by this polymer shell, the NCs display strong stability against water degradation and halide ion migration. Thin films comprising these NCs exhibit a more than 15-fold increase in lifespan in comparison to unprotected NCs in ambient conditions and even survive over 75 days of complete immersion in water. Furthermore, the NCs, which exhibit quantum yields of up to 63% and tunability of the emission wavelength throughout the visible range, show no signs of halide ion exchange. Additionally, heterostructures of MAPI and MAPBr NC layers exhibit efficient Förster resonance energy transfer (FRET), revealing a strategy for optoelectronic integration.
description: This document is the unedited Author version of a Submitted Work that was subsequently accepted for publication in Nano Letters, copyright American Chemical Society after peer review. To access the final edited and published work see http://pubs.acs.org/articlesonrequest/AOR-W59yZfkIX7sG6Xuvp8NE
Local thermometry technique based on proximity-coupled superconductor/normal-metal/superconductor devices
Creators: name: Jiang, Z.
name: Lim, H.
name: Eom, J.
name: Chandrasekhar, V.
Publisher: name: arXiv
Year: 2002
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: In mesoscopic superconductor/normal-metal/superconductor (SNS) heterostructures, it is known that the resistance of the normal metal between the superconductors has a strong temperature dependence. Based on this phenomenon, we have developed a new type of thermometer, which dramatically enhances our ability to measure the local electron temperature Te at low temperatures. Using this technique, we have been able to measure small temperature gradients across a micron-size sample, opening up the possibility of quantitatively measuring the thermal properties of mesoscopic devices.
description: 4 pages, 4 figures
The Hubbard model on the honeycomb lattice: from static and dynamical mean-field theories to lattice quantum Monte Carlo simulations
Creators: name: Raczkowski, Marcin
name: Peters, Robert
name: Phùng, Th\d{i} Thu
name: Takemori, Nayuta
name: Assaad, Fakher F.
name: Honecker, Andreas
name: Vahedi, Javad
Publisher: name: arXiv
Year: 2019
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We study the one-band Hubbard model on the honeycomb lattice using a combination of quantum Monte Carlo (QMC) simulations and static as well as dynamical mean-field theory (DMFT). This model is known to show a quantum phase transition between a Dirac semi-metal and the antiferromagnetic insulator. The aim of this article is to provide a detailed comparison between these approaches by computing static properties, notably ground-state energy, single-particle gap, double occupancy, and staggered magnetization, as well as dynamical quantities such as the single-particle spectral function. At the static mean-field level local moments cannot be generated without breaking the SU(2) spin symmetry. The DMFT approximation accounts for temporal fluctuations, thus captures both the evolution of the double occupancy and the resulting local moment formation in the paramagnetic phase. As a consequence, the DMFT approximation is found to be very accurate in the Dirac semi-metallic phase where local moment formation is present and the spin correlation length small. However, in the vicinity of the fermion quantum critical point the spin correlation length diverges and the spontaneous SU(2) symmetry breaking leads to low-lying Goldstone modes in the magnetically ordered phase. The impact of these spin fluctuations on the single-particle spectral function -- \textit{waterfall} features and narrow spin-polaron bands -- is only visible in the lattice QMC approach.
description: 10 pages + appendix on the structure of the self energy; 5 figures
title: Between Fear Mongers and Samaritans: Does Information Provision Affect Attitudes towards the Right of Asylum in Germany?
title: MAGKS - Joint Discussion Paper Series in Economics
Creators: name: Hayo, Bernd
name: Neumeier, Florian
Publisher: name: Philipps-Universität Marburg
Year: 2020
Subjects: Refugee crisis
Economics
Wirtschaft
right of asylum
perception bias
survey experiment
Germany.
immigration

description: We utilise data from a self-designed survey that includes information experiments to elicit the German public’s attitude towards the right of asylum. The survey was carried out in 2018. We randomly assign 2,048 interviewees to different groups and ‘treat’ each group with different information about the asylum-seekers that came to Germany in 2015 and 2016. Treatments involve information about (i) the total number of asylum-seekers, (ii) the fiscal costs and (iii) potential long-term benefits associated with accepting refugees, (iv) the share of Muslim asylum-seekers, and (v) the share of war refugees. Providing information about the fiscal costs associated with accepting refugees, and, to a lesser extent, about the share of Muslim refugees, significantly increases the likelihood of opposing the right of asylum. These effects are more pronounced for middle-income earners, respondents with a low level of education, and female respondents. Deviations of people’s beliefs from the actual numbers can affect their attitudes: respondents who underestimated the share of Muslim refugees are more likely to call for abolishing the right of asylum.
Optimal eavesdropping in cryptography with three-dimensional quantum states
Creators: name: Bruss, D.
name: Macchiavello, C.
Publisher: name: arXiv
Year: 2001
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study optimal eavesdropping in quantum cryptography with three-dimensional systems, and show that this scheme is more secure than protocols using two-dimensional states. We generalize the according eavesdropping transformation to arbitrary dimensions, and discuss the connection with optimal quantum cloning.
description: 4 pages, 2 figures
Advanced Methods for Diffusion MRI Data Analysis and their Application to the Healthy Ageing Brain
Creators: name: Neto Henriques, Rafael
Publisher: name: Apollo - University of Cambridge Repository
Year: 2018
Subjects: Diffusion MRI
Ageing
Diffusion Kurtosis Imaging
Diffusion Tensor Imaging
MRI
Diffusion
Spherical Deconvolution
Denoising
Tractography
Kurtosis
Free Water Diffusion Tensor Imaging
Microstructure
Modelling

description: Diffusion of water molecules in biological tissues depends on several microstructural properties. Therefore, diffusion Magnetic Resonance Imaging (dMRI) is a useful tool to infer and study microstructural brain changes in the context of human development, ageing and neuropathology. In this thesis, the state-of-the-art of advanced dMRI techniques is explored and strategies to overcome or reduce its pitfalls are developed and validated. Firstly, it is shown that PCA denoising and Gibbs artefact suppression algorithms provide an optimal compromise between increased precision of diffusion measures and the loss of tissue’s diffusion non-Gaussian information. Secondly, the spatial information provided by the diffusion kurtosis imaging (DKI) technique is explored and used to resolve crossing fibres and generalize diffusion measures to cases not limited to well-aligned white matter fibres. Thirdly, as an alternative to diffusion microstructural modelling techniques such as the neurite orientation dispersion and density imaging (NODDI), it is shown that spherical deconvolution techniques can be used to characterize fibre crossing and dispersion simultaneously. Fourthly, free water volume fraction estimates provided by the free water diffusion tensor imaging (fwDTI) are shown to be useful to detect and remove voxels corrupted by cerebrospinal fluid (CSF) partial volume effects. Finally, dMRI techniques are applied to the diffusion data from the large collaborative Cambridge Centre for Ageing and Neuroscience (CamCAN) study. From these data, the inference provided by diffusion anisotropy measures on maturation and degeneration processes is shown to be biased by age-related changes of fibre organization. Inconsistencies of previous NODDI ageing studies are also revealed to be associated with the different age ranges covered. The CamCAN data is also processed using a novel non-Gaussian diffusion characterization technique which is invariant to different fibre configurations. Results show that this technique can provide indices specific to axonal water fraction which can be linked to age-related fibre density changes.
description: This work was funded by the Fundação para a Ciência e a Tecnologia, under the grant SFRH/BD/89114/2012.
Pressure Tuned Magnetism in d- and f-Electron Materials
Creators: name: Haines, Charles Robert Sebastian
Publisher: name: Apollo - University of Cambridge Repository
Year: 2012
Subjects: High Pressure
Strongly Correlated
Quantum Criticality
Heavy Fermion
Quantum Phase Transition

description: Quantum phase transitions (QPT) on the border of magnetism have provided a fertile hunting ground for the discovery of new states of matter, for example; the marginal Fermi Liquid and non Fermi Liquid states as well high T$_C$ cuprate and magnetically mediated superconductivity. In this thesis I present work on three materials in which it may be possible to tune the system through a magnetic QPT with the application of hydrostatic pressure. Although the details of the underlying physics are different in each of the materials, they are linked by the possibility of finding new states on the border of magnetism. Applying hydrostatic pressure, we have suppressed the ferromagnetic (FM) transition in metallic Fe$_2$P to very low temperature and to a potential QPT. Counter-intuitive broadening of the magnetic hysteresis leading up to the FM-AFM QPT may well be a crucial clue as to the nature of the model needed to understand this phase transition. A sharp increase in the quasi-particle scattering cross-section as well as the residual resistivity accompany a departure from the quadratic temperature dependence of the resistivity. This possible deviation from Fermi liquid behaviour is stable over a significant range of temperature. The unexplained upturn in the resistivity of CeGe that accompanies the AFM transition was studied under pressure. Pressure increased the residual resistivity as well as decreasing the relative size of the upturn, but had a moderate effect on the Neel temperature. The insensitivity of the N$\acute e$el temperature to pressure has been compared to its relative sensitivity to applied feld. The existence of the upturn and its evolution with pressure and applied feld can reasonably be argued to be due to the details of the electron band structure in the system. By applying pressure we have drastically reduced the resistivity of the insulating antiferromagnet NiPS$_3$. Concurrent work on FePS$_3$ has shown metallisation under pressure. It seems reasonable to speculate that NiPS$_3$ may also metallise at higher pressure. The energy gap is narrowed in both materials as pressure is increased. Magnetisation measurements have revealed a low temperature upturn indicating some possible ferromagnetic component or proximity to another magnetic state. A peak in the magnetisation is also seen at 45K in zero-feld cooled measurements. Both of these features point to a system with a complex magnetic ground state.
description: EPSRC Doctoral Training Grant
title: The Power of Experiments: How Big is your n?
title: MAGKS - Joint Discussion Paper Series in Economics
Creators: name: Asanov, Igor
name: Bühren, Christoph
name: Zacharodimou, Panagiota
Publisher: name: Philipps-Universität Marburg
Year: 2020
Subjects: balanced randomization
Economics
Wirtschaft
statistical significance
meta-study
Statistical power
caliper test

description: The replicability and credibility crisis in psychology and economics sparked the debate on underpowered experiments, publication biases, and p-hacking. Analyzing the number of independent observations of experiments published in Experimental Economics, Games and Economic Behavior, and the Journal of Economic Behavior and Organization, we observe that we did not learn much from this debate. The median experiment in our sample has too few independent observations and, thus, is underpowered. Moreover, we find indications for biases in reporting highly significant results. We investigate for which papers and experiments it is more likely to find reporting biases, and we suggest remedies that could help to overcome the replicability crisis.
Boundary Liouville Field Theory: Boundary Three Point Function
Creators: name: Ponsot, B.
name: Teschner, J.
Publisher: name: arXiv
Year: 2001
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Liouville field theory is considered on domains with conformally invariant boundary conditions. We present an explicit expression for the three point function of boundary fields in terms of the fusion coefficients which determine the monodromy properties of the conformal blocks.
description: 18 pages; v2: minor changes
MOESM25 of Microbiome of vineyard soils is shaped by geography and management
Creators: name: Coller, Emanuela
name: Cestaro, Alessandro
name: Zanzotti, Roberto
name: Bertoldi, Daniela
name: Pindo, Massimo
name: Larger, Simone
name: Albanese, Davide
name: Mescalchin, Enzo
name: Donati, Claudio
Publisher: name: figshare
Year: 2019
Subjects: subject: Microbiology
subject: FOS: Biological sciences
subject: Evolutionary Biology
subject: Ecology
subject: Science Policy
subject: Plant Biology

description: Additional file 25: Table S12. Linear mixed effect model correlating the the bacterial and fungal Î±-diversities for all sites except PT05 and PT12. Intercept is a treated as a random effect, slope as a fixed effect. (DOCX 13 kb)
Talorchestia Dana 1852
Creators: name: Serejo, Cristiana S.
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Talitridae
Talorchestia

description: Talorchestia Dana, 1852
 Diagnosis. See Morino & Miyamoto (1988).
description: Published as part of Serejo, Cristiana S., 2009, Talitridae *, pp. 892-903 in Zootaxa 2260 (1) on page 896, DOI: 10.11646/zootaxa.2260.1.51, http://zenodo.org/record/5305077
Faint High Latitude Carbon Stars Discovered by the Sloan Digital Sky Survey: Methods and Initial Results
Creators: name: Margon, Bruce
name: Anderson, Scott F.
name: Harris, Hugh C.
name: Strauss, Michael A.
name: Knapp, G. R.
name: Fan, Xiaohui
name: Schneider, Donald P.
name: Berk, Daniel E. Vanden
Publisher: name: arXiv
Year: 2002
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report the discovery of 39 Faint High Latitude Carbon Stars (FHLCs) from Sloan Digital Sky Survey commissioning data. The objects, each selected photometrically and verified spectroscopically, range over 16.6 < r* < 20.0, and show a diversity of temperatures as judged by both colors and NaD line strengths. At the completion of the Sloan Survey, there will be many hundred homogeneously selected and observed FHLCs in this sample. We present proper motion measures for each object, indicating that the sample is a mixture of extremely distant (>100 kpc) halo giant stars, useful for constraining halo dynamics, plus members of the recently-recognized exotic class of very nearby dwarf carbon (dC) stars. Motions, and thus dC classification, are inferred for 40-50 percent of the sample, depending on the level of statistical significance invoked. The new list of dC stars presented here, although selected from only a small fraction of the final SDSS, doubles the number of such objects found by all previous methods. (Abstract abridged).
description: Accepted for publication in The Astronomical Journal, Vol. 124, Sep. 2002, 40 pages, 7 figures, AASTeX v5.0
2-OGC: Open Gravitational-wave Catalog of binary mergers from analysis of public Advanced LIGO and Virgo data
Creators: name: Nitz, Alexander H.
name: Dent, Thomas
name: Davies, Gareth S.
name: Kumar, Sumit
name: Capano, Collin D.
name: Harry, Ian
name: Mozzon, Simone
name: Nuttall, Laura
name: Lundgren, Andrew
name: Tápai, Márton
Publisher: name: arXiv
Year: 2019
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We present the second Open Gravitational-wave Catalog (2-OGC) of compact-binary coalescences, obtained from the complete set of public data from Advanced LIGO's first and second observing runs. For the first time we also search public data from the Virgo observatory. The sensitivity of our search benefits from updated methods of ranking candidate events including the effects of non-stationary detector noise and varying network sensitivity; in a separate targeted binary black hole merger search we also impose a prior distribution of binary component masses. We identify a population of 14 binary black hole merger events with probability of astrophysical origin $> 0.5$ as well as the binary neutron star merger GW170817. We confirm the previously reported events GW170121, GW170304, and GW170727 and also report GW151205, a new marginal binary black hole merger with a primary mass of $67^{+28}_{-17}\,\mathrm{M}_{\odot}$ that may have formed through hierarchical merger. We find no additional significant binary neutron star merger or neutron star--black hole merger events. To enable deeper follow-up as our understanding of the underlying populations evolves, we make available our comprehensive catalog of events, including the sub-threshold population of candidates and posterior samples from parameter inference of the 30 most significant binary black hole candidates.
description: 14 pages, 4 Figures, 4 tables, supplemental materials at https://github.com/gwastro/2-ogc, updated to match version accepted by ApJ
EXPECTED IMPACTS OF BIOTECHNOLOGY ON FOOD SAFETY IN CENTRAL AND EASTERN EUROPEAN COUNTRIES
Creators: name: Bakucs, Lajos Zoltan
name: Ferto, Imre
name: Bakucs, Lajos Zoltan
name: Ferto, Imre
Publisher: name: Unknown
Year: 2010
Subjects: subject: Food Consumption/Nutrition/Food Safety
subject: International Development
subject: Biotechnology
subject: Food Safety
subject: Central-European Countries
subject: Technology Foresight

description: Use of biotechnology in agricultural and food production has become one the most controversial issue in the last decade. Food safety is a crucial aspect of human life and therefore it is an issue of prime importance to the EU, however research on transition countries is practically nonexistent. We focus on Hungary, Slovakia, the Czech Republic, Slovenia and Romania using a Key Technology Survey, to analyse the biotechnologies that might have a strong impact upon food quality and health. We first investigate the likely future impacts of biotechnology on food safety than we employ foresight methodology. Third we apply cross-country comparison instead focusing on just one country. Results suggest that CEE countries are laggards in the development and application of biotechnology. We find that experts evaluate rather positively the effects of biotechnology on various types of hazards and large differences can be observed among country experts to assess these impacts.
A novel attention model for salient structure detection in seismic volumes
Creators: name: Shafiq, Muhammad Amir
name: Long, Zhiling
name: Di, Haibin
name: AlRegib, Ghassan
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Image and Video Processing (eess.IV)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: A new approach to seismic interpretation is proposed to leverage visual perception and human visual system modeling. Specifically, a saliency detection algorithm based on a novel attention model is proposed for identifying subsurface structures within seismic data volumes. The algorithm employs 3D-FFT and a multi-dimensional spectral projection, which decomposes local spectra into three distinct components, each depicting variations along different dimensions of the data. Subsequently, a novel directional center-surround attention model is proposed to incorporate directional comparisons around each voxel for saliency detection within each projected dimension. Next, the resulting saliency maps along each dimension are combined adaptively to yield a consolidated saliency map, which highlights various structures characterized by subtle variations and relative motion with respect to their neighboring sections. A priori information about the seismic data can be either embedded into the proposed attention model in the directional comparisons, or incorporated into the algorithm by specifying a template when combining saliency maps adaptively. Experimental results on two real seismic datasets from the North Sea, Netherlands and Great South Basin, New Zealand demonstrate the effectiveness of the proposed algorithm for detecting salient seismic structures of different natures and appearances in one shot, which differs significantly from traditional seismic interpretation algorithms. The results further demonstrate that the proposed method outperforms comparable state-of-the-art saliency detection algorithms for natural images and videos, which are inadequate for seismic imaging data.
description: Published in Applied Computing and Intelligence, Nov. 2021
Production of hepatocytes from human pluripotent stem cells for cell-based therapy
Creators: name: Geti, Imbisaat
Publisher: name: Apollo - University of Cambridge Repository
Year: 2019
Subjects: Hepatocytes
Cell based therapy
regenerative medicine
liver
liver differentiation
hepatocytes differentiation

description: Human pluripotent stem cells (hPSCs) can self-renew indefinitely in vitro while maintaining the capacity to differentiate into diverse cell types, including hepatocytes. Thus, hPSCs allow for large-scale production of hepatocytes necessary for cell-based therapy. Importantly, cell-based therapy involving the transplantation of hepatocytes-like cells (HLCs) represent a promising alternative to liver transplantation. However, there are two major limitations that must be overcome before hPSCs derived hepatocytes can go into clinical trials. Firstly, current protocols are not compatible with Good Manufacturing Practice (GMP) as they rely on culture media which are poorly defined and contain reagents of animal origin. Secondly, HLCs derived in vitro lack the full spectrum of adult hepatocyte functionalities and expressed foetal markers indicating that they are not equivalent to primary cells. In this dissertation, I describe a method for generating a homogenous population of hepatocytes from hPSCs in conditions compatible with clinical applications. Furthermore, I show that the resulting GMP-like protocol is equally robust as research grade protocol to produce HLCs displaying key characteristics of their in vivo counterparts. Importantly, the efficacy of this new GMP protocol was validated in five different hPSCs lines, including three GMP grade human Embryonic Stem Cell lines. Finally, we have also characterized the resulting cells in vivo and demonstrated their safety after transplantation into immune deficient mice. In parallel, I have optimised our protocol of differentiation by establishing a 5 steps method that closely follows liver development. For the development of this protocol, I have screened a large number of culture conditions and identified optimum time points for each step especially for hepatoblast and foetal hepatocytes stage. Overall, the work presented in this dissertation has advanced the differentiation of hPSCs for cell-based therapy in two different ways. Firstly, it shows that production of HLCs in GMP like condition is feasible, safe and that the resulting cells could be useful for cell-based therapy in the context of liver diseases. Secondly, I have developed a new protocol with an optimised hepatoblast stage that will facilitate further clinical applications.
Dōsen Dai Nihon kokusaizu. Jō
銅鐫大日本國細圖 上
Creators: name: Matsuda, Ryokuzan.
Publisher: name: Kyōto : Katsumura Jiemon and twenty-one others
Year: 2021

description: Volume 1 begins with maps of Japan and the world, followed by maps of individual provinces. Roads, towns, castles and provinces indicated. Gengendō is the shop name of Matsuda Ryokuzan.
Opening of DNA double strands by helicases. Active versus passive opening
Creators: name: Betterton, M. D.
name: Julicher, F.
Publisher: name: arXiv
Year: 2002
Subjects: subject: Biological Physics (physics.bio-ph)
subject: Soft Condensed Matter (cond-mat.soft)
subject: Biomolecules (q-bio.BM)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: Helicase opening of double-stranded nucleic acids may be "active" (the helicase directly destabilizes the dsNA to promote opening) or "passive" (the helicase binds ssNA available due to a thermal fluctuation which opens part of the dsNA). We describe helicase opening of dsNA, based on helicases which bind single NA strands and move towards the double-stranded region, using a discrete ``hopping'' model. The interaction between the helicase and the junction where the double strand opens is characterized by an interaction potential. The form of the potential determines whether the opening is active or passive. We calculate the rate of passive opening for the helicase PcrA, and show that the rate increases when the opening is active. Finally, we examine how to choose the interaction potential to optimize the rate of strand separation. One important result is our finding that active opening can increase the unwinding rate by 7 fold compared to passive opening.
description: 13 pages, 3 figures
From Cubism to Non-Objective Art: Sonia and Robert Delaunay's Exchange with Russian Artists
Creators: name: Willaman Baltaxe, Cinthia
Publisher: name: Apollo - University of Cambridge Repository
Year: 2019
Subjects: Orphism
Non-Objective Art
Cubism
Russian Avant-Garde
Delaunay

description: This dissertation examines the early history and development of Cubism, Orphism and Non-Objective art through the artistic exchange between Sonia and Robert Delaunay and Russian avant-garde artists. Previous scholars have studied the work of the Delaunays primarily within the context of isolated movements and geographical confines. This approach has prevented us from fully grasping the ways in which the Delaunays’ work influenced the wider, international avant-garde phenomenon. My methodology is the first to reconsider the Delaunays’ pivotal shift from Cubism to Non-Objective art, and how this influenced other artists, resituating them within the transnational history of the avant-garde in the early twentieth century. By analysing published and archival sources, international exhibitions and their critical reception, and the exchange of ideas between Russia and Europe, this project presents an innovative understanding of how pre-war artists experimented with Non-Objective art. Taken together, my research advances scholarship on pre-1914 avant-gardism, the Russian avant-garde, Non-Objective art, and Sonia and Robert Delaunay, broadening discussions of influence and revealing new nuances of crucial developments in numerous artists’ approaches to visual art. This dissertation provides a much needed study of the Delaunays’ dialogue with Russian artists, who were instrumental in the development of abstract art and who marked a significant contribution to international artistic discourse. Moreover, it challenges the established narrative that Robert alone was the primary stimulus for Russian artists. Instead, by shifting the focus to a broader pan-European and Russian perspective, my work sheds new light on the involvement of Sonia, as well as Robert, in these changes.
MOESM23 of Microbiome of vineyard soils is shaped by geography and management
Creators: name: Coller, Emanuela
name: Cestaro, Alessandro
name: Zanzotti, Roberto
name: Bertoldi, Daniela
name: Pindo, Massimo
name: Larger, Simone
name: Albanese, Davide
name: Mescalchin, Enzo
name: Donati, Claudio
Publisher: name: figshare
Year: 2019
Subjects: subject: Microbiology
subject: FOS: Biological sciences
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: Ecology
subject: 69999 Biological Sciences not elsewhere classified
subject: Plant Biology

description: Additional file 23: Table S10. Linear model correlating the the bacterial and fungal Î±-diversities for PT05. (DOCX 13 kb)
Small, Highly Accurate Quantum Processor for Intermediate-Depth Quantum Simulations
Creators: name: Lysne, Nathan K.
name: Kuper, Kevin W.
name: Poggi, Pablo M.
name: Deutsch, Ivan H.
name: Jessen, Poul S.
Publisher: name: arXiv
Year: 2019
Subjects: subject: Quantum Physics (quant-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Analog quantum simulation is widely considered a step on the path to fault tolerant quantum computation. If based on current noisy hardware, the accuracy of an analog simulator will degrade after just a few time steps, especially when simulating complex systems that are likely to exhibit quantum chaos. Here we describe a small, highly accurate quantum simulator and its use to run high fidelity simulations of three different model Hamiltonians for $>100$ time steps. While not scalable to exponentially large Hilbert spaces, this platform provides the accuracy and programmability required for systematic exploration of the interplay between dynamics, imperfections, and accuracy in quantum simulation.
description: Published version. 10 pages, 5 figures, including Supplemental Material
Probing Molecular Ordering in the Nematic Phases of para-Linked Bimesogen Dimers through NMR Studies of Flexible Prochiral Solutes
Creators: name: Heist, Leah M.
name: Samulski, Edward T.
name: Welch, Chris
name: Ahmed, Ziauddin
name: Mehl, Georg H.
name: Vanakaras, Alexandros G.
name: Photinos, Demetri J.
Publisher: name: arXiv
Year: 2019
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: The quadrupolar splittings of perdeuteriated n-decane dissolved in nematic phases formed by mesogenic dimers of the CBnCB series, for n=7,9,10,11 are measured throughout the entire temperature range of these phases. The results of the measurements, are reported together with related measurements using the common nematic phase of 5CB as a solvent for n-decane. The data obtained from the $^{13}$C spectra of the cyanobiphenyl mesogenic units of the monomeric and dimeric solvent molecules yield the order parameter of those units. The information obtained from this set of experiments is used to elucidate the structure of the low temperature (N$_X$) and the high temperature (N) nematic phases of CBnCB dimers with n=7,9,11. The polar twisted nematic (N$_{PT}$) model is found to provide a consistent description not only of these measurements, but also of NMR measurements previously reported in the literature for these phases. These findings suggest that the high temperature nematic (N) is not a common, locally uniaxial and apolar nematic, but rather a nematic phase consisting of N$_{PT}$ clusters. The twist-bend (N$_{TB}$) model, often identified with the N$_X$ phase, is shown to be inadequate to account even qualitatively for crucial features of the experimental findings.
description: 41 pages, 8 figures, 1 appendix, supplementary material