cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Quantifying the global atmospheric power budget
Creators: name: Makarieva, Anastassia M.
name: Gorshkov, Victor G.
name: Nefiodov, Andrei V.
name: Sheil, Douglas
name: Nobre, Antonio Donato
name: Li, Bai-Lian
Publisher: name: arXiv
Year: 2016
Subjects: subject: Atmospheric and Oceanic Physics (physics.ao-ph)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: The power of atmospheric circulation is a key measure of the Earth's climate system. The mismatch between predictions and observations under a warming climate calls for a reassessment of how atmospheric power $W$ is defined, estimated and constrained. Here we review published formulations for $W$ and show how they differ when applied to a moist atmosphere. Three factors, a non-zero source/sink in the continuity equation, the difference between velocities of gaseous air and condensate, and interaction between the gas and condensate modifying the equations of motion, affect the formulation of $W$. Starting from the thermodynamic definition of mechanical work, we derive an expression for $W$ from an explicit consideration of the equations of motion and continuity. Our analyses clarify how some past formulations are incomplete or invalid. Three caveats are identified. First, $W$ critically depends on the boundary condition for gaseous air velocity at the Earth's surface. Second, confusion between gaseous air velocity and mean velocity of air and condensate in the expression for $W$ results in gross errors despite the observed magnitudes of these velocities are very close. Third, $W$ expressed in terms of measurable atmospheric parameters, air pressure and velocity, is scale-specific; this must be taken into account when adding contributions to $W$ from different processes. We present a formulation of the atmospheric power budget, which distinguishes three components of $W$: the kinetic power associated with horizontal pressure gradients ($W_K$), the gravitational power of precipitation ($W_P$) and the condensate loading ($W_c$). We use MERRA and NCAR/NCEP re-analyses to evaluate the atmospheric power budget at different scales: $W_K$ increases with temporal resolution approaching our theoretical estimate for condensation-induced circulation when all convective motion is resolved.
description: 55 pages, 14 figures; minor revisions after another discussion, see https://doi.org/10.5194/acp-2017-17-AC7 and www.bioticregulation.ru/ab.php?id=he
Topological Phases in InAs$_{1-x}$Sb$_x$: From Novel Topological Semimetal to Majorana Wire
Creators: name: Winkler, Georg W.
name: Wu, QuanSheng
name: Troyer, Matthias
name: Krogstrup, Peter
name: Soluyanov, Alexey A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Superconductor proximitized one-dimensional semiconductor nanowires with strong spin-orbit interaction (SOI) are at this time the most promising candidates for the realization of topological quantum information processing. In current experiments the SOI originates predominantly from extrinsic fields, induced by finite size effects and applied gate voltages. The dependence of the topological transition in these devices on microscopic details makes scaling to a large number of devices difficult unless a material with dominant intrinsic bulk SOI is used. Here we show that wires made of certain ordered alloys InAs$_{1-x}$Sb$_x$ have spin-splittings up to 20 times larger than those reached in pristine InSb wires. In particular, we show this for a stable ordered CuPt-structure at $x = 0.5$, which has an inverted band ordering and realizes a novel type of a topological semimetal with triple degeneracy points in the bulk spectrum that produce topological surface Fermi arcs. Experimentally achievable strains can drive this compound either into a topological insulator phase, or restore the normal band ordering making the CuPt-ordered InAs$_{0.5}$Sb$_{0.5}$ a semiconductor with a large intrinsic linear in $k$ bulk spin splitting.
description: 6 pages, 5 figures
Modeling Variations of First-Order Horn Abduction in Answer Set Programming
Creators: name: Schüller, Peter
Publisher: name: arXiv
Year: 2015
Subjects: subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences
subject: 68N17

description: We study abduction in First Order Horn logic theories where all atoms can be abduced and we are looking for preferred solutions with respect to three objective functions: cardinality minimality, coherence, and weighted abduction. We represent this reasoning problem in Answer Set Programming (ASP), in order to obtain a flexible framework for experimenting with global constraints and objective functions, and to test the boundaries of what is possible with ASP. Realizing this problem in ASP is challenging as it requires value invention and equivalence between certain constants, because the Unique Names Assumption does not hold in general. To permit reasoning in cyclic theories, we formally describe fine-grained variations of limiting Skolemization. We identify term equivalence as a main instantiation bottleneck, and improve the efficiency of our approach with on-demand constraints that were used to eliminate the same bottleneck in state-of-the-art solvers. We evaluate our approach experimentally on the ACCEL benchmark for plan recognition in Natural Language Understanding. Our encodings are publicly available, modular, and our approach is more efficient than state-of-the-art solvers on the ACCEL benchmark.
description: Technical Report
Brane webs in the presence of an $O5^-$-plane and 4d class S theories of type D
Creators: name: Zafrir, Gabi
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this article we conjecture a relationship between 5d SCFT's, that can be engineered by 5-brane webs in the presence of an $O5^-$-plane, and 4d class S theories of type D. The specific relation is that compactification on a circle of the former leads to the latter. We present evidence for this conjecture. One piece of evidence, which is also an interesting application of this, is that it suggests identifications between different class S theories. This can in turn be tested by comparing their central charges.
description: 30 pages, 18 figures; v2 minor revision, version published in JHEP
Dynamical signatures of bound states in waveguide QED
Creators: name: Sánchez-Burillo, E.
name: Zueco, D.
name: Martín-Moreno, L.
name: García-Ripoll, J. J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We study the spontaneous decay of an impurity coupled to a linear array of bosonic cavities forming a single-band photonic waveguide. The average frequency of the emitted photon is different from the frequency for single-photon resonant scattering, which perfectly matches the bare frequency of the excited state of the impurity. We study how the energy of the excited state of the impurity influences the spatial profile of the emitted photon. The farther the energy is from the middle of the photonic band, the farther the wave packet is from the causal limit. In particular, if the energy lies in the middle of the band, the wave packet is localized around the causal limit. Besides, the occupation of the excited state of the impurity presents a rich dynamics: it shows an exponential decay up to intermediate times, this is followed by a power-law tail in the long-time regime, and it finally reaches an oscillatory stationary regime. Finally, we show that this phenomenology is robust under the presence of losses, both in the impurity and the cavities.
Rydberg dressing of a one-dimensional Bose-Einstein condensate
Creators: name: Płodzień, Marcin
name: Lochead, Graham
name: de Hond, Julius
name: van Druten, N. J.
name: Kokkelmans, Servaas
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We study the influence of Rydberg dressed interactions in a one-dimensional (1D) Bose-Einstein Condensate (BEC). We show that a 1D geometry offers several advantages over 3D for observing BEC Rydberg dressing. The effects of dressing are studied by investigating collective BEC dynamics after a rapid switch-off of the Rydberg dressing interaction. The results can be interpreted as an effective modification of the s-wave scattering length. We include this modification in an analytical model for the 1D BEC, and compare it to numerical calculations of Rydberg dressing under realistic experimental conditions.
description: 5 pages, 3 figures
Listening to an alpine intermittent stream: Development of an autonomous microcontroller device to measure water level
Creators: name: Fässler, Linus
name: Osborne, Wm. Alexander
name: Ceperley, Natalie
name: Leiser, Peter
name: Schaefli, Bettina
Publisher: name: Zenodo
Year: 2023
Subjects: IRES
Teensy 3.2 + Audio Shield
Arduino IDE
Self-developed data-logger
Acoustics of streams
Water level detection

description: Intermittent rivers and ephemeral streams (IRES) account for 50% of the world's flows. Climate change leads to an increase in intermittent streams from perennial streams. Recently, IRES have been found to be very important for carbon and nitrogen cycling and ecosystem functions. Despite recent attention towards IRES, spatial and temporal data lack, especially in mountain areas. Conventional measuring techniques depend on devices that have certain limitations, for example, they are placed in the streambed, where they get destroyed or displaced during a heavy stream flow event. This thesis presents a self-developed, low-cost audio sensor that can derive the water level of an IRES using only sound. In addition to an audio sensor, a time-lapse camera constantly documented the streambed and captured the water level at thirty-minute intervals. The water level determined from the images and the audio files is strongly correlated with a 95% coefficient of determination (R2). We can calculate the water level using the audio data with the exponential regression function, as long as there is some water in the stream. This work demonstrates the possibility of an audio sensor to obtain reliable water level data in an IRES and offers a legitimate alternative to conventional measuring methods. This technological advance offers a new affordable, accessible tool that can be widely used and thus increase monitoring of the flow of IRES at a large scale.
Listening to an alpine intermittent stream: Development of an autonomous microcontroller device to measure water level
Creators: name: Fässler, Linus
name: Osborne, Wm. Alexander
name: Ceperley, Natalie
name: Leiser, Peter
name: Schaefli, Bettina
Publisher: name: Zenodo
Year: 2023
Subjects: IRES
Teensy 3.2 + Audio Shield
Arduino IDE
Self-developed data-logger
Acoustics of streams
Water level detection

description: Intermittent rivers and ephemeral streams (IRES) account for 50\% of the world's flows. Climate change leads to an increase in intermittent streams from perennial streams. Recently, IRES have been found to be very important for carbon and nitrogen cycling and ecosystem functions. Despite recent attention towards IRES, spatial and temporal data lack, especially in mountain areas. Conventional measuring techniques depend on devices that have certain limitations, for example, they are placed in the streambed, where they get destroyed or displaced during a heavy stream flow event. This thesis presents a self-developed, low-cost audio sensor that can derive the water level of an IRES using only sound. In addition to an audio sensor, a time-lapse camera constantly documented the streambed and captured the water level at thirty-minute intervals. The water level determined from the images and the audio files is strongly correlated with a 95\% coefficient of determination ($R^2$). We can calculate the water level using the audio data with the exponential regression function, as long as there is some water in the stream. This work demonstrates the possibility of an audio sensor to obtain reliable water level data in an IRES and offers a legitimate alternative to conventional measuring methods. This technological advance offers a new affordable, accessible tool that can be widely used and thus increase monitoring of the flow of IRES at a large scale.
Right Bousfield Localization and Operadic Algebras
Creators: name: White, David
name: Yau, Donald
Publisher: name: arXiv
Year: 2015
Subjects: subject: Algebraic Topology (math.AT)
subject: Category Theory (math.CT)
subject: K-Theory and Homology (math.KT)
subject: Rings and Algebras (math.RA)
subject: Representation Theory (math.RT)
subject: FOS: Mathematics

description: It is well known that under some general conditions right Bousfield localization exists. We provide general conditions under which right Bousfield localization yields a monoidal model category. Then we address the questions of when this monoidal model structure on a right Bousfield localization induces a model structure on the category of algebras over a colored operad and when a right Bousfield localization preserves colored operadic algebras. We give numerous applications, to topological spaces, equivariant spaces, chain complexes, stable module categories, and to the category of small categories. We recover a wide range of classical results as special cases of our theory, and prove several new preservation results.
description: version 2 adds new results proving that algebras over operads in G spaces and G spectra admit transferred model structures. There are also new algebraic examples. Edits made in response to a referee
Cosmological stealths with nonconformal couplings
Creators: name: Ayón-Beato, Eloy
name: Ramírez-Baca, P. Isaac
name: Terrero-Escalante, César A.
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 - Theory (hep-th)
subject: FOS: Physical sciences

description: In this paper we reconsider the existence of stealth fields during the evolution of our Universe by admitting more realistic nonminimal couplings to gravity than the conformal one. In the framework of the FRW cosmology we found that inhomogeneous stealths, as those enabled in the conformal case, are only allowed in de Sitter backgrounds. In particular, it is shown that the homogeneous stealths resulting from nonconformal couplings can coexist with each kind of matter dominant in the several phases characterizing the evolution of our Universe according to the $Λ$CDM model.
description: 16 pages, 10 figures Approved to appear at Phys. Rev. D
Upper and Lower Critical Decay Exponents of Ising Ferromagnets with Long-range Interaction
Creators: name: Horita, Toshiki
name: Suwa, Hidemaro
name: Todo, Synge
Publisher: name: arXiv
Year: 2016
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We investigate the universality class of the finite-temperature phase transition of the two-dimensional Ising model with the algebraically decaying ferromagnetic long-range interaction, $J_{ij} = |\vec{r}_i -\vec{r}_j|^{-(d+σ)}$, where $d$ (=2) is the dimension of the system and $σ$ the decay exponent, by means of the order-$N$ cluster-algorithm Monte Carlo method. In particular, we focus on the upper and lower critical decay exponents, the boundaries between the mean-field-universality, intermediate, and short-range-universality regimes. At the critical decay exponents, it is found that the critical amplitude of the standard Binder ratio of magnetization exhibits the extremely slow convergence as a function of the system size. We propose more effective physical quantities, the combined Binder ratio and the self-combined Binder ratio, both of which cancel the leading finite-size corrections of the conventional Binder ratio. Utilizing these techniques, we clearly demonstrate that in two dimensions the lower and upper critical decay exponents are $σ= 1$ and 7/4, respectively, contrary to the recent Monte Carlo and the renormalization-group studies [M. Picco, arXiv:1207.1018; T. Blanchard, et al., Europhys. Lett. 101, 56003 (2013)].
description: 12 pages, 7 figures
Investigating the effects of cysteine-118 oxidation on G12D KRas structure and dynamics: insights from MD simulations
Creators: name: Salamh, Shimaa
name: Sayyed-Ahmad, Abdallah
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Biophysics
subject: Biochemistry
classificationCode: 39999
subject: Chemical Sciences not elsewhere classified
classificationCode: 69999
subject: Biological Sciences not elsewhere classified
subject: Cancer
subject: Computational Biology

description: Mutations of Ras proteins are believed to be among the most prominent causes of cancer. There is increasing evidence that the activity of Ras may be controlled by the redox state of cysteine residues located within the NKCD motif. This redox signaling is critical to both physiological and pathological processes and occurs when C118 is oxidized in a reversible manner. In this study, we used atomistic molecular dynamics simulations and Markov state models to investigate the structural and conformational effects of C118 oxidation on the oncogenic mutant KRas(G12D). While both mutants share common features and exhibit some distinct conformational states and fluctuations, we have found that the oxidized variant KRas(G12D/C118SOH) is more dynamic than the unoxidized counterpart, particularly in the switch II region. Additionally, C118 oxidation is found to alter the structure of the nucleotide-binding site and the switch regions as well as perturb the conformational equilibrium between Ras active and inactive states. These conformational preferences may alter the affinity to different effectors, resulting in selective downstream activation. Our results are anticipated to help future drug development efforts aimed at KRAS-related anticancer treatment. Communicated by Ramaswamy H. Sarma
Parabolic conformally symplectic structures I; definition and distinguished connections
Creators: name: Cap, Andreas
name: Salac, Tomas
Publisher: name: arXiv
Year: 2016
Subjects: subject: Differential Geometry (math.DG)
subject: Symplectic Geometry (math.SG)
subject: FOS: Mathematics
subject: 53D15, 53B15, 53C10, 53C15 (Primary), 53C29, 53C55 (Secondary)

description: We introduce a class of first order G-structures, each of which has an underlying almost conformally symplectic structure. There is one such structure for each real simple Lie algebra which is not of type $C_n$ and admits a contact grading. We show that a structure of each of these types on a smooth manifold $M$ determines a canonical compatible linear connection on the tangent bundle $TM$. This connection is characterized by a normalization condition on its torsion. The algebraic background for this result is proved using Kostant's theorem on Lie algebra cohomology. For each type, we give an explicit description of both the geometric structure and the normalization condition. In particular, the torsion of the canonical connection naturally splits into two components, one of which is exactly the obstruction to the underlying structure being conformally symplectic. This article is the first in a series aiming at a construction of differential complexes naturally associated to these geometric structures.
description: 25 pages, comments are welcome v2: minimal corrections, added arXiv-coordinates of parts II and III; v3: numbering corrected to comply with published version and some small changes, final version to appear in Forum Math
Neurofeedback Tunes Scale-Free Dynamics in Spontaneous Brain Activity
Creators: name: Ros, Tomas
name: Frewen, Paul
name: Theberge, Jean
name: Kluetsch, Rosemarie
name: Mueller, Andreas
name: Candrian, Gian
name: Jetly, Rakesh
name: Vuilleumier, Patrik
name: Lanius, Ruth
Publisher: name: arXiv
Year: 2015
Subjects: subject: Neurons and Cognition (q-bio.NC)
subject: FOS: Biological sciences

description: Brain oscillations exhibit long-range temporal correlations (LRTCs), which reflect the regularity of their fluctuations: low values representing more random (decorrelated) while high values more persistent (correlated) dynamics. LRTCs constitute supporting evidence that the brain operates near criticality, a state where neuronal activities are balanced between order and randomness. Here, healthy adults used closed-loop brain training (neurofeedback, NFB) to reduce the amplitude of alpha oscillations, producing a significant increase in spontaneous LRTCs post-training. This effect was reproduced in patients with post-traumatic stress disorder, where abnormally random dynamics were reversed by NFB, correlating with significant improvements in hyperarousal. Notably, regions manifesting abnormally low LRTCs (i.e., excessive randomness) normalized toward healthy population levels, consistent with theoretical predictions about self-organized criticality. Hence, when exposed to appropriate training, spontaneous cortical activity reveals a residual capacity for "self-tuning" its own temporal complexity, despite manifesting the abnormal dynamics seen in individuals with psychiatric disorder. Lastly, we observed an inverse-U relationship between strength of LRTC and oscillation amplitude, suggesting a breakdown of long-range dependence at high/low synchronization extremes, in line with recent computational models. Together, our findings offer a broader mechanistic framework for motivating research and clinical applications of NFB, encompassing disorders with perturbed LRTCs.
Superfield Hamiltonian quantization in terms of quantum antibrackets
Creators: name: Batalin, Igor A.
name: Lavrov, Peter M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We develop a new version of the superfield Hamiltonian quantization. The main new feature is that the BRST-BFV charge and the gauge fixing Fermion are introduced on equal footing within the sigma model approach, which provides for the actual use of the quantum/derived antibrackets. We study in detail the generating equations for the quantum antibrackets and their primed counterparts. We discuss the finite quantum anticanonical transformations generated by the quantum antibracket.
description: 16 pages, v2: Appendix extended, references added, published version, v3: Section 3 extended, v4: minor corrections
Liquid-solvent Direct Air Capture process model ouput
Creators: name: Shorey, Patrick
name: Abdulla, Ahmed
Publisher: name: Carleton University
Year: 2024

description: Simulated performance of a nominal 1 Megatonne CO2 per year liquid-solvent Direct Air Capture facility for a range of inlet temperature, humidity, CO2 concentration and pressure. Formatted as netCDF (.nc). This model output will be published as part of the article "Liquid solvent Direct Air Capture's cost and carbon dioxide removal vary with ambient environmental conditions" in Communications Earth & Environment, by Patrick Shorey and Ahmed Abdulla.
Size-Driven Quantum Phase Transitions
Creators: name: Bausch, Johannes
name: Cubitt, Toby S.
name: Lucia, Angelo
name: Perez-Garcia, David
name: Wolf, Michael M.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Quantum Physics (quant-ph)
subject: Other Condensed Matter (cond-mat.other)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 82B10

description: Can the properties of the thermodynamic limit of a many-body quantum system be extrapolated by analysing a sequence of finite-size cases? We present a model for which such an approach gives completely misleading results: a translationally invariant, local Hamiltonian on a square lattice with open boundary conditions and constant spectral gap, which has a classical product ground state for all system sizes smaller than a particular threshold size, but a ground state with topological degeneracy for all system sizes larger than this threshold. Starting from a minimal case with spins of dimension 6 and threshold lattice size 15 x 15, we show that the latter grows faster than any computable function with increasing local spin dimension. The resulting effect may be viewed as a new type of quantum phase transition that is driven by the size of the system rather than by an external field or coupling strength. We prove that the construction is thermally robust, opening the possibility that these effects are accessible to experimental observation.
description: 20 pages. Final version
Depositional environment and provenance of Early Carboniferous clastic sedimentary rocks at McIsaacs Point, Nova Scotia: Implications for syntectonic basin development during the formation of Pangaea
Creators: name: Malay, Bailey C.
name: Braid, James A.
name: Archibald, Donnelly B.
name: McFarlane, Chris R.M.
Publisher: name: Geological Society of London
Year: 2023
Subjects: subject: Geology
subject: FOS: Earth and related environmental sciences

description: U–Pb data
Negative emissions—Part 1: Research landscape and synthesis
Creators: name: Minx, Jan C.
name: Lamb, William F.
name: Callaghan, Max W.
name: Fuss, Sabine
name: Hilaire, Jérôme
name: Creutzig, Felix
name: Amann, Thorben
name: Beringer, Tim
name: De Oliveira Garcia, Wagner
name: Hartmann, Jens
name: Khanna, Tarun
name: Lenzi, Dominic
name: Luderer, Gunnar
name: Nemet, Gregory F.
name: Rogelj, Joeri
name: Smith, Pete
name: Vicente Vicente, José Luis
name: Wilcox, Jennifer
name: Del Mar Zamora Dominguez, Maria
Publisher: name: Bristol : IOP Publ.
Year: 2018
Subjects: subject: afforestation and reforestation
subject: bioenergy combined with carbon capture and storage (BECCS)
subject: carbon dioxide removal (CDR)
subject: direct air capture
subject: enhanced weathering
subject: negative emissions
subject: soil carbon sequestration and biochar
subject: 690

description: With the Paris Agreement's ambition of limiting climate change to well below 2 °C, negative emission technologies (NETs) have moved into the limelight of discussions in climate science and policy. Despite several assessments, the current knowledge on NETs is still diffuse and incomplete, but also growing fast. Here, we synthesize a comprehensive body of NETs literature, using scientometric tools and performing an in-depth assessment of the quantitative and qualitative evidence therein. We clarify the role of NETs in climate change mitigation scenarios, their ethical implications, as well as the challenges involved in bringing the various NETs to the market and scaling them up in time. There are six major findings arising from our assessment: first, keeping warming below 1.5 °C requires the large-scale deployment of NETs, but this dependency can still be kept to a minimum for the 2 °C warming limit. Second, accounting for economic and biophysical limits, we identify relevant potentials for all NETs except ocean fertilization. Third, any single NET is unlikely to sustainably achieve the large NETs deployment observed in many 1.5 °C and 2 °C mitigation scenarios. Yet, portfolios of multiple NETs, each deployed at modest scales, could be invaluable for reaching the climate goals. Fourth, a substantial gap exists between the upscaling and rapid diffusion of NETs implied in scenarios and progress in actual innovation and deployment. If NETs are required at the scales currently discussed, the resulting urgency of implementation is currently neither reflected in science nor policy. Fifth, NETs face severe barriers to implementation and are only weakly incentivized so far. Finally, we identify distinct ethical discourses relevant for NETs, but highlight the need to root them firmly in the available evidence in order to render such discussions relevant in practice.
Volume, facets and dual polytopes of twinned chain polytopes
Creators: name: Tsuchiya, Akiyoshi
Publisher: name: arXiv
Year: 2015
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 52B05, 52B20

description: Let $(P,\leq_P)$ and $(Q,\leq_Q)$ be finite partially ordered sets with $|P|=|Q|=d$, and $\mathcal{C}(P) \subset \mathbb{R}^d$ and $\mathcal{C}(Q) \subset \mathbb{R}^d$ their chain polytopes. The twinned chain polytope of $P$ and $Q$ is the lattice polytope $Γ(\mathcal{C}(P),\mathcal{C}(Q)) \subset \mathbb{R}^d$ which is the convex hull of $\mathcal{C}(P) \cup (-\mathcal{C}(Q))$. It is known that twinned chain polytopes are Gorenstein Fano polytopes with the integer decomposition property. In the present paper, we study combinatorial properties of twinned chain polytopes. First, we will give the formula of the volume of twinned chain polytopes in terms of the underlying partially ordered sets. Second, we will identify the facet-supporting hyperplanes of twinned chain polytopes in terms of the underlying partially ordered sets. Finally, we will provide the vertex representations of the dual polytopes of twinned chain polytopes.
description: 10 pages, to appear in Annals of Combinatorics
Worldwide evaluation of mean and extreme runoff from six global-scale hydrological models that account for human impacts
Creators: name: Zaherpour, Jamal
name: Gosling, Simon N.
name: Mount, Nick
name: Müller Schmied, Hannes
name: Veldkamp, Ted I. E.
name: Dankers, Rutger
name: Eisner, Stephanie
name: Gerten, Dieter
name: Gudmundsson, Lukas
name: Haddeland, Ingjerd
name: Hanasaki, Naota
name: Kim, Hyungjun
name: Leng, Guoyong
name: Liu, Junguo
name: Masaki, Yoshimitsu
name: Oki, Taikan
name: Pokhrel, Yadu
name: Satoh, Yusuke
name: Schewe, Jacob
name: Wada, Yoshihide
Publisher: name: Bristol : IOP Publ.
Year: 2018
Subjects: subject: extreme events
subject: global hydrological models
subject: human impacts
subject: land surface models
subject: model evaluation
subject: model validation
subject: 690

description: Global-scale hydrological models are routinely used to assess water scarcity, flood hazards and droughts worldwide. Recent efforts to incorporate anthropogenic activities in these models have enabled more realistic comparisons with observations. Here we evaluate simulations from an ensemble of six models participating in the second phase of the Inter-Sectoral Impact Model Inter-comparison Project (ISIMIP2a). We simulate monthly runoff in 40 catchments, spatially distributed across eight global hydrobelts. The performance of each model and the ensemble mean is examined with respect to their ability to replicate observed mean and extreme runoff under human-influenced conditions. Application of a novel integrated evaluation metric to quantify the models' ability to simulate timeseries of monthly runoff suggests that the models generally perform better in the wetter equatorial and northern hydrobelts than in drier southern hydrobelts. When model outputs are temporally aggregated to assess mean annual and extreme runoff, the models perform better. Nevertheless, we find a general trend in the majority of models towards the overestimation of mean annual runoff and all indicators of upper and lower extreme runoff. The models struggle to capture the timing of the seasonal cycle, particularly in northern hydrobelts, while in southern hydrobelts the models struggle to reproduce the magnitude of the seasonal cycle. It is noteworthy that over all hydrological indicators, the ensemble mean fails to perform better than any individual model—a finding that challenges the commonly held perception that model ensemble estimates deliver superior performance over individual models. The study highlights the need for continued model development and improvement. It also suggests that caution should be taken when summarising the simulations from a model ensemble based upon its mean output.
Spin and Charge Resolved Quantum Gas Microscopy of Antiferromagnetic Order in Hubbard Chains
Creators: name: Boll, Martin
name: Hilker, Timon A.
name: Salomon, Guillaume
name: Omran, Ahmed
name: Nespolo, Jacopo
name: Pollet, Lode
name: Bloch, Immanuel
name: Gross, Christian
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: The repulsive Hubbard Hamiltonian is one of the foundational models describing strongly correlated electrons and is believed to capture essential aspects of high temperature superconductivity. Ultracold fermions in optical lattices allow for the simulation of the Hubbard Hamiltonian with a unique control over kinetic energy, interactions and doping. A great challenge is to reach the required low entropy and to observe antiferromagnetic spin correlations beyond nearest neighbors, for which quantum gas microscopes are ideal. Here we report on the direct, single-site resolved detection of antiferromagnetic correlations extending up to three sites in spin-$1/2$ Hubbard chains, which requires an entropy well below $s^*=\ln(2)$. Finally, the simultaneous detection of spin and density opens the route towards the study of the interplay between magnetic ordering and doping in various dimensions.
description: Updated author list
New class of quantum error-correcting codes for a bosonic mode
Creators: name: Michael, Marios H.
name: Silveri, Matti
name: Brierley, R. T.
name: Albert, Victor V.
name: Salmilehto, Juha
name: Jiang, Liang
name: Girvin, S. M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We construct a new class of quantum error-correcting codes for a bosonic mode which are advantageous for applications in quantum memories, communication, and scalable computation. These 'binomial quantum codes' are formed from a finite superposition of Fock states weighted with binomial coefficients. The binomial codes can exactly correct errors that are polynomial up to a specific degree in bosonic creation and annihilation operators, including amplitude damping and displacement noise as well as boson addition and dephasing errors. For realistic continuous-time dissipative evolution, the codes can perform approximate quantum error correction to any given order in the timestep between error detection measurements. We present an explicit approximate quantum error recovery operation based on projective measurements and unitary operations. The binomial codes are tailored for detecting boson loss and gain errors by means of measurements of the generalized number parity. We discuss optimization of the binomial codes and demonstrate that by relaxing the parity structure, codes with even lower unrecoverable error rates can be achieved. The binomial codes are related to existing two-mode bosonic codes but offer the advantage of requiring only a single bosonic mode to correct amplitude damping as well as the ability to correct other errors. Our codes are similar in spirit to 'cat codes' based on superpositions of the coherent states, but offer several advantages such as smaller mean number, exact rather than approximate orthonormality of the code words, and an explicit unitary operation for repumping energy into the bosonic mode. The binomial quantum codes are realizable with current superconducting circuit technology and they should prove useful in other quantum technologies, including bosonic quantum memories, photonic quantum communication, and optical-to-microwave up- and down-conversion.
description: Published version
Increasing Human Performance by Sharing Cognitive Load Using Brain-to-Brain Interface
Creators: name: Maksimenko, Vladimir A.
name: Hramov, Alexander E.
name: Frolov, Nikita S.
name: Lüttjohann, Annika
name: Nedaivozov, Vladimir O.
name: Grubov, Vadim V.
name: Runnova, Anastasia E.
name: Makarov, Vladimir V.
name: Kurths, Jürgen
name: Pisarchik, Alexander N.
Publisher: name: Lausanne : Frontiers Research Foundation
Year: 2018
Subjects: subject: Brain states recognition
subject: Brain-computer interface (BCI)
subject: Brain-to-brain interface (BBI)
subject: Cognitive performance
subject: Cognitive reserve
subject: Human-to-human interaction
subject: Mental fatigue
subject: Visual attention
subject: 610

description: Brain-computer interfaces (BCIs) attract a lot of attention because of their ability to improve the brain's efficiency in performing complex tasks using a computer. Furthermore, BCIs can increase human's performance not only due to human-machine interactions, but also thanks to an optimal distribution of cognitive load among all members of a group working on a common task, i.e., due to human-human interaction. The latter is of particular importance when sustained attention and alertness are required. In every day practice, this is a common occurrence, for example, among office workers, pilots of a military or a civil aircraft, power plant operators, etc. Their routinely work includes continuous monitoring of instrument readings and implies a heavy cognitive load due to processing large amounts of visual information. In this paper, we propose a brain-to-brain interface (BBI) which estimates brain states of every participant and distributes a cognitive load among all members of the group accomplishing together a common task. The BBI allows sharing the whole workload between all participants depending on their current cognitive performance estimated from their electrical brain activity. We show that the team efficiency can be increased due to redistribution of the work between participants so that the most difficult workload falls on the operator who exhibits maximum performance. Finally, we demonstrate that the human-to-human interaction is more efficient in the presence of a certain delay determined by brain rhythms. The obtained results are promising for the development of a new generation of communication systems based on neurophysiological brain activity of interacting people. Such BBIs will distribute a common task between all group members according to their individual physical conditions.
Adaptive Learning Rate via Covariance Matrix Based Preconditioning for Deep Neural Networks
Creators: name: Ida, Yasutoshi
name: Fujiwara, Yasuhiro
name: Iwamura, Sotetsu
Publisher: name: arXiv
Year: 2016
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: Adaptive learning rate algorithms such as RMSProp are widely used for training deep neural networks. RMSProp offers efficient training since it uses first order gradients to approximate Hessian-based preconditioning. However, since the first order gradients include noise caused by stochastic optimization, the approximation may be inaccurate. In this paper, we propose a novel adaptive learning rate algorithm called SDProp. Its key idea is effective handling of the noise by preconditioning based on covariance matrix. For various neural networks, our approach is more efficient and effective than RMSProp and its variant.
description: Accepted at IJCAI 2017
Topological cell clustering in the ATLAS calorimeters and its performance in LHC Run 1
Creators: name: ATLAS Collaboration
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The reconstruction of the signal from hadrons and jets emerging from the proton-proton collisions at the Large Hadron Collider (LHC) and entering the ATLAS calorimeters is based on a three-dimensional topological clustering of individual calorimeter cell signals. The cluster formation follows cell signal-significance patterns generated by electromagnetic and hadronic showers. In this, the clustering algorithm implicitly performs a topological noise suppression by removing cells with insignificant signals which are not in close proximity to cells with significant signals. The resulting topological cell clusters have shape and location information, which is exploited to apply a local energy calibration and corrections depending on the nature of the cluster. Topological cell clustering is established as a well-performing calorimeter signal definition for jet and missing transverse momentum reconstruction in ATLAS.
description: 83 pages plus author list (100 pages in total), 44 figures, 3 tables, final version published in EPJC. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/PERF-2014-07/
The Effect of Obliquity-Driven Changes on Paleoclimate Sensitivity During the Late Pleistocene
Creators: name: Köhler, Peter
name: Knorr, Gregor
name: Stap, Lennert B.
name: Ganopolski, Andrey
name: De Boer, Bas
name: Van De Wal, Roderik S. W.
name: Barker, Stephen
name: Rüpke, Lars H.
Publisher: name: Hoboken, NJ : Wiley
Year: 2018
Subjects: subject: climate sensitivity
subject: ECS
subject: Pleistocene
subject: proxies
subject: simulation
subject: state dependence
subject: 550

description: We reanalyze existing paleodata of global mean surface temperature ΔTg and radiative forcing ΔR of CO2 and land ice albedo for the last 800,000 years to show that a state-dependency in paleoclimate sensitivity S, as previously suggested, is only found if ΔTg is based on reconstructions, and not when ΔTg is based on model simulations. Furthermore, during times of decreasing obliquity (periods of land ice sheet growth and sea level fall) the multimillennial component of reconstructed ΔTg diverges from CO2, while in simulations both variables vary more synchronously, suggesting that the differences during these times are due to relatively low rates of simulated land ice growth and associated cooling. To produce a reconstruction-based extrapolation of S for the future, we exclude intervals with strong ΔTg-CO2 divergence and find that S is less state-dependent, or even constant state-independent), yielding a mean equilibrium warming of 2–4 K for a doubling of CO2.
Discrepancy and Eigenvalues of Cayley Graphs
Creators: name: Kohayakawa, Yoshiharu
name: Rödl, Vojtěch
name: Schacht, Mathias
Publisher: name: arXiv
Year: 2016
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: Primary: 05C50. Secondary: 05C80

description: We consider quasirandom properties for Cayley graphs of finite abelian groups. We show that having uniform edge-distribution (i.e., small discrepancy) and having large eigenvalue gap are equivalent properties for such Cayley graphs, even if they are sparse. This positively answers a question of Chung and Graham ["Sparse quasi-random graphs", Combinatorica 22 (2002), no. 2, 217-244] for the particular case of Cayley graphs of abelian groups, while in general the answer is negative.
description: Dedicated to the memory of Professor Miroslav Fiedler, 33 pages, second version addresses changes arising from the referee report and includes an appendix with an earlier argument
Evaluation of climate-related carbon turnover processes in global vegetation models for boreal and temperate forests
Creators: name: Thurner, Martin
name: Beer, Christian
name: Ciais, Philippe
name: Friend, Andrew D.
name: Ito, Akihiko
name: Kleidon, Axel
name: Lomas, Mark R.
name: Quegan, Shaun
name: Rademacher, Tim T.
name: Schaphoff, Sibyll
name: Tum, Markus
name: Wiltshire, Andy
name: Carvalhais, Nuno
Publisher: name: Oxford [u.a.] : Blackwell Science
Year: 2017
Subjects: subject: boreal and temperate forest
subject: climate-related spatial gradients
subject: drought stress and insect outbreaks
subject: forest mortality
subject: frost stress
subject: global vegetation model evaluation
subject: ISI-MIP
subject: remote sensing based NPP and biomass
subject: vegetation carbon turnover rate
subject: 570

description: Turnover concepts in state-of-the-art global vegetation models (GVMs) account for various processes, but are often highly simplified and may not include an adequate representation of the dominant processes that shape vegetation carbon turnover rates in real forest ecosystems at a large spatial scale. Here, we evaluate vegetation carbon turnover processes in GVMs participating in the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP, including HYBRID4, JeDi, JULES, LPJml, ORCHIDEE, SDGVM, and VISIT) using estimates of vegetation carbon turnover rate (k) derived from a combination of remote sensing based products of biomass and net primary production (NPP). We find that current model limitations lead to considerable biases in the simulated biomass and in k (severe underestimations by all models except JeDi and VISIT compared to observation-based average k), likely contributing to underestimation of positive feedbacks of the northern forest carbon balance to climate change caused by changes in forest mortality. A need for improved turnover concepts related to frost damage, drought, and insect outbreaks to better reproduce observation-based spatial patterns in k is identified. As direct frost damage effects on mortality are usually not accounted for in these GVMs, simulated relationships between k and winter length in boreal forests are not consistent between different regions and strongly biased compared to the observation-based relationships. Some models show a response of k to drought in temperate forests as a result of impacts of water availability on NPP, growth efficiency or carbon balance dependent mortality as well as soil or litter moisture effects on leaf turnover or fire. However, further direct drought effects such as carbon starvation (only in HYBRID4) or hydraulic failure are usually not taken into account by the investigated GVMs. While they are considered dominant large-scale mortality agents, mortality mechanisms related to insects and pathogens are not explicitly treated in these models.
Impact of Service Sector Loads on Renewable Resource Integration
Creators: name: Voulis, Nina
name: Warnier, Martijn
name: Brazier, Frances M. T.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: Urban areas consist of a mix of households and services, such as offices, shops, schools, etc. Yet most urban energy models only consider household load profiles, omitting the service sector. Realistic assessment of the potential for renewable resource integration in cities requires models that include detailed demand and generation profiles. Detailed generation profiles are available for many resources. Detailed demand profiles, however, are currently only available for households and not for the service sector. This paper addresses this gap. The paper (1) proposes a novel approach to devise synthetic service sector demand profiles based on a combination of a large number of different data sources, and (2) uses these profiles to study the impact of the service sector on the potential for renewable resource integration in urban energy systems, using the Netherlands as a case study. The importance of the service sector is addressed in a broad range of solar and wind generation scenarios, and in specific time and weather conditions (in a single scenario). Results show that including the service sector leads to statistically significantly better estimations of the potential of renewable resource integration in urban areas. In specific time and weather conditions, including the service sector results in estimations that are up to 33% higher than if only households are considered. The results can be used by researchers to improve urban energy systems models, and by decision-makers and practitioners for grid planning, operation and management}.
description: 32 pages, 7 figures, 4 tables