cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Ethical, Legal, and Social Implications (ELSI) of DNA-based Technologies for Disaster Victim Identification (DVI)
Creators: name: Katsanis, Sara
name: Madden, Diana
Publisher: name: Center for ELSI Resources and Analysis
Year: 2021
Subjects: subject: Genetics
subject: FOS: Biological sciences
subject: Ethics
subject: Science
subject: ELSI
subject: DVI
subject: forensic DNA
subject: DNA identification
subject: mass fatality

description: As we mark the 20th anniversary of the attacks on the World Trade Center and Washington, D.C. that occurred on September 11, 2001, we reflect on the pain and loss of the events that shook the entire world, some of us very personally. Here, we also pause to note the progress and missteps that this day brought forth in disaster victim identification (DVI) efforts. At the time of the attacks, DVI protocols were still minimal and the U.S. federal database for crime and missing persons (the Combined DNA Index System, CODIS) was only three years old. Within hours of the attack, the Office of Chief Medical Examiner in New York City led a strategy to establish victim family centers. The ad hoc practices that emerged in those first days and months became both patterns for success and cautionary lessons. DVI challenges include how to share data, protect privacy, and obtain consent, in addition to how to communicate unexpected family relationships and employ trauma-informed practices for family reference sample management. In the last 20 years, DNA-based technologies have evolved to allow, for instance, testing of minuscule DNA fragments and analysis of samples within hours via rapid DNA instruments. These advances allow more and faster identifications in mass fatality events, but also bring new ELSI questions on when to apply technologies, how to prioritize and fund efforts, and how to manage data among stakeholders and families. One lesson we took from that day 20 years ago is preparedness – that both emotional and practical preparation can minimize challenges in the aftermath of a mass fatality. In remembering the victims of 9/11, both dead and alive, we look back on the scientific contributions resulting from this mass fatality and the ongoing ethical, legal, and social implications of using forensic data in humanitarian efforts.
Corneal retardation time as an ocular hypertension disease indicator
Creators: name: del Barco, Oscar
name: Avila, Francisco J.
name: Marcellán, Concepción
name: Remón, Laura
Publisher: name: arXiv
Year: 2023
Subjects: subject: Biological Physics (physics.bio-ph)
subject: FOS: Physical sciences

description: Objective. A detailed analysis of the corneal retardation time $τ$ as a highly related parameter to the intraocular pressure (IOP), and its plausible role as an indicator of ocular hypertension disease. Approach. A simple theoretical expression for $τ$ is derived within the corneal viscoelastic model of Kelvin-Voigt with 3 elements. This retardation time can be easily calculated from the well-known signal and pressure amplitudes of non-contact tonometers like the Ocular Response Analyzer (ORA). Then, a population-based study was performed where 100 subjects aged from 18 to 30 were analyzed (within this group, about 10% had an elevated IOP with more than 21 mmHg). Main results. A clear relationship between the corneal retardation time and the corneal-compensated intraocular pressure was found, underlying the risk for ocular hypertensive (OHT) subjects with lower $τ$ values to develop hypertension illnesses (due to the inability of poorly viscoelastic corneas to absorb IOP fluctuations, resulting in probable optic nerve damage). Significance. Our results might provide an useful tool to systematically discern which OHT patients (and even those with normal IOP values) are more likely to suffer glaucoma progression and, consequently, ensure an early diagnosis.
description: Accepted for publication in Biomedical Physics and Engineering Express
Factors affecting DNA methylation in the sperm of men with male factor infertility
Creators: name: Ng, Richard
Publisher: name: University of British Columbia
Year: 2017

description: Infertility currently affects an estimated 8-12% of couples globally and the male factor is suspected as the primary cause in about half of these cases. There are several identified genetic causes for male infertility such as Y chromosome microdeletions and chromosomal rearrangements; however, these known genetic causes only account for 15-30% of male infertility cases, with the majority being idiopathic. Recently, there has been a shift toward studying epigenetic mechanisms as a potential avenue to explain idiopathic cases of male infertility. Most commonly, DNA methylation of imprinted genes is studied as these genes are not erased from gamete to embryo and the function of these genes is critical for embryonic development. Furthermore, methylation of DNA is tightly linked to the folate cycle as the metabolism of folate generates the methyl donors used in methylation reactions. There is also evidence to suggest DNA damage may affect methylation by producing an inadequate substrate for methylation enzymes. We investigated DNA methylation, the folate cycle, and DNA damage in men with oligospermia and azoospermia and compared these to fertile control men. Similar to previously published studies, we found that the sperm of infertile men carries methylation defects in imprinted genes. To further the analysis, we investigated if any relationship with folate enzyme genotypes or folate concentration exists. The genotypes of folate enzymes were not different between groups and there were no effects on DNA methylation. We observed that the concentration of folate was positively correlated with GTL2 methylation, but no correlations were found for any other regions. Finally, GST genotypes and DNA fragmentation were examined for possible associations with DNA methylation. The frequency GST genotypes were not different between groups and had no effect on DNA methylation. DNA fragmentation was also determined to have no associations with DNA methylation. We provide evidence that DNA methylation at imprinted genes in the sperm of infertile men may be affected by folate concentration. The modest association found here can be supplemented in future studies by expanding the coverage of DNA methylation to other regions, investigating homocysteine and methionine, or adding a measure of ROS.
Terahertz radiation due to random grating coupled surface plasmon polaritons
Creators: name: Shubina, T. V.
name: Gippius, N. A.
name: Shalygin, V. A.
name: Andrianov, A. V.
name: Ivanov, S. V.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences
subject: 78-05

description: We report on terahertz (THz) radiation under electrical pumping from a degenerate semiconductor possessing an electron accumulation layer. In InN, the random grating formed by topographical defects provides high-efficiency coupling of surface plasmon polaritons supported by the accumulation layer to the THz emission. The principal emission band occupies the 2-6 THz spectral range. We establish a link between the shape of emission spectra and the structural factor of the random grating and show that the change of slope of power dependencies is characteristic for temperature-dependent plasmonic mechanisms. The super-linear rise of a THz emission intensity on applied electric power provides advantage of such materials in emission yield.
description: 4 pages, 4 figures
Impact of public prescription drug coverage on newer hepatitis C medicines in British Columbia
Creators: name: Ho, Harriet
Publisher: name: University of British Columbia
Year: 2017

description: Background: Sofosbuvir and ledipasvir-sofosbuvir are breakthrough direct-acting antiviral agents (DAAs) for the treatment of hepatitis C virus (HCV) infection. These drugs were very expensive at initial listing with a price of around $60,000 CAD. However, the cure rates and side effect profiles showed drastic improvements compared to interferon-based treatments. Given limited real-world data on adherence to DAAs, this study examined adherence to sofosbuvir and ledipasvir-sofosbuvir, and identified factors associated with adherence. It also examined the impact of public prescription drug coverage (PharmaCare) on adherence, treatment uptake, and expenditure. Methods: This study used data from the British Columbia Hepatitis Testers Cohort. Adherence was measured as proportion of days covered (PDC), calculated from prescription drug data. I used multivariable logistic regression to examine the impact of various factors on full adherence (PDC=100%). I also used interrupted time series analysis to examine the impact of PharmaCare coverage on adherence, treatment uptake, and public and private expenditure over time. Results: Of 3,730 treatments initiated, 2,760 were eligible for analysis; 786 were treated with sofosbuvir, 1,974 were treated with ledipasvir-sofosbuvir, and 14 were treated with both. Mean PDC across both drugs, sofosbuvir, and ledipasvir-sofosbuvir were 96.17%, 95.35%, and 96.50% respectively. In the multivariable logistic regression model, several factors were statistically significant. Major mental illness, longer treatment durations, moderate socioeconomic status, and being of white ethnicity were all associated with lower proportions of individuals with full adherence. Having PharmaCare coverage and being over the age of 60 were associated with higher proportions of individuals with full adherence. In the interrupted time series analysis, the availability of PharmaCare coverage for sofosbuvir and ledipasvir-sofosbuvir did not impact trends in adherence, but did increase treatment uptake of both drugs. Furthermore, public expenditure increased after the policy change, crowding out some of the private expenditure. Conclusion: Given the high cost of these drugs, the high adherence rates found are encouraging. Strategies to target those with major mental illness and longer treatment durations should be explored. Payers should also be prepared for increased treatment uptake and public expenditures following the availability of public coverage.
The risk of indoor sports and culture events for the transmission of COVID-19
Creators: name: Moritz, Stefan
name: Gottschick, Cornelia
name: Horn, Johannes
name: Popp, Mario
name: Langer, Susan
name: Klee, Bianca
name: Purschke, Oliver
name: Gekle, Michael
name: Ihling, Angelika
name: Mikolajczyk, Rafael
Publisher: name: Universitäts- und Landesbibliothek Sachsen-Anhalt
Year: 2021
Subjects: subject: 610

description: Nearly all mass gathering events worldwide were banned at the beginning of the COVID-19 pandemic, as they were suspected of presenting a considerable risk for the transmission of SARS-CoV-2. We investigated the risk of transmitting SARS-CoV-2 by droplets and aerosols during an experimental indoor mass gathering event under three different hygiene practices, and used the data in a simulation study to estimate the resulting burden of disease under conditions of controlled epidemics. Our results show that the mean number of measured direct contacts per visitor was nine persons and this can be reduced substantially by appropriate hygiene practices. A comparison of two versions of ventilation with different air exchange rates and different airflows found that the system which performed worst allowed a ten-fold increase in the number of individuals exposed to infectious aerosols. The overall burden of infections resulting from indoor mass gatherings depends largely on the quality of the ventilation system and the hygiene practices. Presuming an effective ventilation system, indoor mass gathering events with suitable hygiene practices have a very small, if any, effect on epidemic spread.
Academic Stories - Provocations
Creators: name: Cuthbert, Kate
Publisher: name: National Teaching Repository
Year: 2022
Subjects: subject: Uncategorized
subject: 130103 Higher Education
subject: FOS: Educational sciences

description: This series of provocation cards were used to facilitate discussions during a team building event for educational development.
The cards invite discussion about the role, professional identity and the way in which educational development happens within a Higher Education Institution.
Assembling PNIPAM-Capped Gold Nanoparticles in Aqueous Solutions
Creators: name: Nayak, Binay P.
name: Kim, Hyeong Jin
name: Nayak, Srikanth
name: Wang, Wenjie
name: Bu, Wei
name: Mallapragada, Surya K.
name: Vaknin, David
Publisher: name: arXiv
Year: 2023
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: Employing small angle X-ray scattering (SAXS), we explore the conditions under which the assembly of gold nanoparticles (AuNPs) grafted with the thermo-sensitive polymer Poly(N-isopropylacrylamide) (PNIPAM) emerges. We find that short-range order assembly emerges by combining the addition of electrolytes or poly-electrolytes with raising the temperature of the suspensions above the lower-critical solution temperature (LCST) of PNIPAM. Our results show that the longer the PNIPAM chain is, the better organization in the assembled clusters. Interestingly, without added electrolytes, there is no evidence of AuNP assembly as a function of temperature, although untethered PNIPAM is known to undergo a coil-to-globule transition above its LCST. This study demonstrates another approach to assembling potential thermo-sensitive nanostructures for devices by leveraging the unique properties of PNIPAM.
description: Published at ACS Macro Letters, DOI - https://doi.org/10.1021/acsmacrolett.3c00617
Smooth perturbations of the functional calculus and applications to Riemannian geometry on spaces of metrics
Creators: name: Bauer, Martin
name: Bruveris, Martins
name: Harms, Philipp
name: Michor, Peter W.
Publisher: name: arXiv
Year: 2018
Subjects: subject: Differential Geometry (math.DG)
subject: Spectral Theory (math.SP)
subject: FOS: Mathematics
subject: 46T05 (primary) 58E10, 47A56 (secondary)

description: We show for a certain class of operators $A$ and holomorphic functions $f$ that the functional calculus $A\mapsto f(A)$ is holomorphic. Using this result we are able to prove that fractional Laplacians $(1+Δ^g)^p$ depend real analytically on the metric $g$ in suitable Sobolev topologies. As an application we obtain local well-posedness of the geodesic equation for fractional Sobolev metrics on the space of all Riemannian metrics.
description: 32 pages, minor revision
Hamiltonian vs stability in alternative theories of gravity
Creators: name: Esposito-Farese, Gilles
Publisher: name: arXiv
Year: 2019
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: When a Hamiltonian density is bounded by below, we know that the lowest-energy state must be stable. One is often tempted to reverse the theorem and therefore believe that an unbounded Hamiltonian density always implies an instability. The main purpose of this presentation (which summarizes my work with E. Babichev, C. Charmousis and A. Lehébel) is to pedagogically explain why this is erroneous. Stability is indeed a coordinate-independent property, whereas the Hamiltonian density does depend on the choice of coordinates. In alternative theories of gravity, like k-essence or Horndeski theories, the correct stability criterion is a subtler version of the well-known "Weak Energy Condition" of general relativity. As an illustration, this criterion is applied to an exact Schwarzschild-de Sitter solution of a Horndeski theory, which is found to be stable for a given range of its parameters, contrary to a claim in the literature.
description: 9 pages, 2 figures, uses the LaTeX class file "moriond.cls", contribution to the 2019 Gravitation session of the 54th Rencontres de Moriond
Closed surfaces with different shapes that are indistinguishable by the SRNF
Creators: name: Klassen, Eric
name: Michor, Peter W.
Publisher: name: arXiv
Year: 2019
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 53A05, 58D15

description: The Square Root Normal Field (SRNF), introduced by Jermyn et al. in [3], provides a way of representing immersed surfaces in $\mathbb R^3$, and equipping the set of these immersions with a "distance function" (to be precise, a pseudometric) that is easy to compute. Importantly, this distance function is invariant under reparametrizations (i.e., under self-diffeomorphisms of the domain surface) and under rigid motions of $\mathbb R^3$. Thus, it induces a distance function on the shape space of immersions, i.e., the space of immersions modulo reparametrizations and rigid motions of $\mathbb R^3$. In this paper, we give examples of the degeneracy of this distance function, i.e., examples of immersed surfaces (some closed and some open) that have the same SRNF, but are not the same up to reparametrization and rigid motions. We also prove that the SRNF does distinguish the shape of a standard sphere from the shape of any other immersed surface, and does distinguish between the shapes of any two embedded strictly convex surfaces.
description: 6 pages
Threshold for Blowup and Stability for Nonlinear Schrödinger Equation with Rotation
Creators: name: Basharat, Nyla
name: Hajaiej, Hichem
name: Hu, Yi
name: Zheng, Shijun
Publisher: name: arXiv
Year: 2020
Subjects: subject: Analysis of PDEs (math.AP)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 35Q55, 37K45, 35P25

description: We consider the focusing NLS with an angular momentum and a harmonic potential, which models Bose-Einstein condensate under a rotating magnetic trap. We give a sharp condition on the global existence and blowup in the mass-critical case. We further consider the stability of such systems via variational method. We determine that at the critical exponent $p=1+4/n$, the mass of $Q$, the ground state for the NLS with zero potential, is the threshold for both finite time blowup and orbital instability. Moreover, we prove a sharp threshold theorem for the rotational NLS with an inhomogeneous nonlinearity. The analysis relies on the existence of ground state as well as a virial identity for the associated kinetic-magnetic operator.
description: 44 pages. Theorem 1.2 is improved to a sharp version concerning RNLS with an inhomogeneous nonlinearity. Among others, examples are provided to verify the blow-up criteria in Lemma 4.1. A few references are updated
A Gigapixel Computational Light-Field Camera
Creators: name: Gregory, Thomas
name: Edgar, Matthew P.
name: Gibson, Graham M.
name: Moreau, Paul-Antoine
Publisher: name: arXiv
Year: 2019
Subjects: subject: Optics (physics.optics)
subject: Image and Video Processing (eess.IV)
subject: FOS: Physical sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Light-field cameras allow the acquisition of both the spatial and angular components of the light. This has a wide range of applications from image refocusing to 3D reconstruction of a scene. The conventional way to perform such acquisitions leads to a strong spatio-angular resolution limit. Here we propose a computational version of the light-field camera. We perform a one gigapixel photo-realistic diffraction limited light-field acquisition, that would require the use of a one gigapixel sensor were the acquisition to be performed with a conventional light-field camera. This result is mostly limited by the total acquisition time, as our system could in principle allow $\sim$Terapixel reconstructions to be achieved. The reported result presents many potential advantages, such as the possibility to perform large depth of field light-field acquisitions, realistic refocusing along a very wide range of depths, very high dimensional super-resolved image acquisitions, and large depth of field 3D reconstructions.
Two-Loop Five-Parton Leading-Colour Finite Remainders in the Spinor-Helicity Formalism
Creators: name: De Laurentis, Giuseppe
name: Maître, Daniel
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We present all two-loop five-parton leading-colour finite remainders in the spinor-helicity formalism by analysing numerical evaluations of their known expressions in terms of Mandelstam invariants. Recasting them in terms of spinor-helicity variables allows us to obtain expressions which are more compact, faster to evaluate, numerically more stable and manifestly free from poles of higher order than necessary. At the same time, due to the better scaling of our reconstruction strategy with the complexity of the input, we required one order of magnitude fewer numerical samples to complete the analytical reconstruction than were needed by the authors of Ref. \cite{Abreu:2019odu}, albeit using higher numerical working precision. This places our reconstruction technique as an alternative to the finite-field single-numerator reconstruction for future applications.
description: 21 page, 4 figures - published version, added a note to anc/README
Correlation functions of spinor current multiplets in ${\mathcal N}=1$ superconformal theory
Creators: name: Buchbinder, Evgeny I.
name: Hutomo, Jessica
name: Kuzenko, Sergei M.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We consider ${\mathcal N}=1$ superconformal field theories in four dimensions possessing an additional conserved spinor current multiplet $S_α$ and study three-point functions involving such an operator. A conserved spinor current multiplet naturally exists in superconformal theories with ${\mathcal N}=2$ supersymmetry and contains the current of the second supersymmetry. However, we do not assume ${\mathcal N}=2$ supersymmetry. We show that the three-point function of two spinor current multiplets and the ${\mathcal N}=1$ supercurrent depends on three independent tensor structures and, in general, is not contained in the three-point function of the ${\mathcal N}=2$ supercurrent. It then follows, based on symmetry considerations only, that the existence of one more Grassmann odd current multiplet in ${\mathcal N}=1$ superconformal field theory does not necessarily imply ${\mathcal N}=2$ superconformal symmetry.
description: 41 pages; V2: Typos corrected, published version; V3: minor corrections
Exploiting Emotional Dependencies with Graph Convolutional Networks for Facial Expression Recognition
Creators: name: Antoniadis, Panagiotis
name: Filntisis, Panagiotis P.
name: Maragos, Petros
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Over the past few years, deep learning methods have shown remarkable results in many face-related tasks including automatic facial expression recognition (FER) in-the-wild. Meanwhile, numerous models describing the human emotional states have been proposed by the psychology community. However, we have no clear evidence as to which representation is more appropriate and the majority of FER systems use either the categorical or the dimensional model of affect. Inspired by recent work in multi-label classification, this paper proposes a novel multi-task learning (MTL) framework that exploits the dependencies between these two models using a Graph Convolutional Network (GCN) to recognize facial expressions in-the-wild. Specifically, a shared feature representation is learned for both discrete and continuous recognition in a MTL setting. Moreover, the facial expression classifiers and the valence-arousal regressors are learned through a GCN that explicitly captures the dependencies between them. To evaluate the performance of our method under real-world conditions we perform extensive experiments on the AffectNet and Aff-Wild2 datasets. The results of our experiments show that our method is capable of improving the performance across different datasets and backbone architectures. Finally, we also surpass the previous state-of-the-art methods on the categorical model of AffectNet.
description: 9 pages, 8 figures, 5 tables, revised submission to the 16th IEEE International Conference on Automatic Face and Gesture Recognition
Diagonal reduction algebra for $\mathfrak{osp}(1|2)$
Creators: name: Hartwig, Jonas T.
name: Williams, Dwight Anderson
Publisher: name: arXiv
Year: 2021
Subjects: subject: Representation Theory (math.RT)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: The problem of providing complete presentations of reduction algebras associated to a pair of Lie algebras $(\mathfrak{G},\mathfrak{g})$ has previously been considered by Khoroshkin and Ogievetsky in the case of the diagonal reduction algebra for $\mathfrak{gl}(n)$. In this paper we consider the diagonal reduction algebra of the pair of Lie superalgebras $\left(\mathfrak{osp}(1|2) \times \mathfrak{osp}(1|2), \mathfrak{osp}(1|2)\right)$ as a double coset space having an associative diamond product and give a complete presentation in terms of generators and relations. We also provide a PBW basis for this reduction algebra along with Casimir-like elements and a subgroup of automorphisms.
description: 24 pages; v4; attempted to improve readability and thoroughness
Optimal Communication Rates and Combinatorial Properties for Common Randomness Generation
Creators: name: Han, Yanjun
name: Tatwawadi, Kedar
name: Kurri, Gowtham R.
name: Zhou, Zhengqing
name: Prabhakaran, Vinod M.
name: Weissman, Tsachy
Publisher: name: arXiv
Year: 2019
Subjects: subject: Information Theory (cs.IT)
subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: Combinatorics (math.CO)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: We study common randomness generation problems where $n$ players aim to generate same sequences of random coin flips where some subsets of the players share an independent common coin which can be tossed multiple times, and there is a publicly seen blackboard through which the players communicate with each other. We provide a tight representation of the optimal communication rates via linear programming, and more importantly, propose explicit algorithms for the optimal distributed simulation for a wide class of hypergraphs. In particular, the optimal communication rate in complete hypergraphs is still achievable in sparser hypergraphs containing a path-connected cycle-free cluster of topologically connected components. Some key steps in analyzing the upper bounds rely on two different definitions of connectivity in hypergraphs, which may be of independent interest.
description: 17 pages, 10 figures
Multiple Access Channel Simulation
Creators: name: Kurri, Gowtham R.
name: Ramachandran, Viswanathan
name: Pillai, Sibi Raj B.
name: Prabhakaran, Vinod M.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: We study the problem of simulating a two-user multiple-access channel (MAC) over a multiple access network of noiseless links. Two encoders observe independent and identically distributed (i.i.d.) copies of a source random variable each, while a decoder observes i.i.d. copies of a side-information random variable. There are rate-limited noiseless communication links between each encoder and the decoder, and there is independent pairwise shared randomness between all the three possible pairs of nodes. The decoder has to output approximately i.i.d. copies of another random variable jointly distributed with the two sources and the side information. We are interested in the rate tuples which permit this simulation. This setting can be thought of as a multi-terminal generalization of the point-to-point channel simulation problem studied by Bennett et al. (2002) and Cuff (2013). When the pairwise shared randomness between the encoders is absent, the setting reduces to a special case of MAC simulation using another MAC studied by Haddadpour et al.~(2013). We establish that the presence of encoder shared randomness can strictly improve the communication rate requirements. We first show that the inner bound derived from Haddadpour et al.~(2013) is tight when the sources at the encoders are conditionally independent given the side-information at the decoder. This result recovers the existing results on point-to-point channel simulation and function computation over such multi-terminal networks. We then explicitly compute the communication rate regions for an example both with and without the encoder shared randomness and demonstrate that its presence strictly reduces the communication rates. Inner and outer bounds for the general case are also obtained.
description: 30 pages, 3 figures
Hearts for commutative noetherian rings: torsion pairs and derived equivalences
Creators: name: Pavon, Sergio
name: Vitória, Jorge
Publisher: name: arXiv
Year: 2020
Subjects: subject: Representation Theory (math.RT)
subject: Commutative Algebra (math.AC)
subject: Category Theory (math.CT)
subject: FOS: Mathematics
subject: 13D30, 13D09, 18E10, 18G80

description: Over a commutative noetherian ring $R$, the prime spectrum controls, via the assignment of support, the structure of both $\mathsf{Mod}(R)$ and $\mathsf{D}(R)$. We show that, just like in $\mathsf{Mod}(R)$, the assignment of support classifies hereditary torsion pairs in the heart of any nondegenerate compactly generated $t$-structure of $\mathsf{D}(R)$. Moreover, we investigate whether these $t$-structures induce derived equivalences, obtaining a new source of Grothendieck categories which are derived equivalent to $\mathsf{Mod}(R)$.
description: 24 pages, comments are welcome! Version 2 contains some minor changes and clarifications
Impact-Aware Task-Space Quadratic-Programming Control
Creators: name: Wang, Yuquan
name: Dehio, Niels
name: Tanguy, Arnaud
name: Kheddar, Abderrahmane
Publisher: name: arXiv
Year: 2020
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: Robots usually establish contacts at rigid surfaces with near-zero relative velocities. Otherwise, impact-induced energy propagates in the robot's linkage and may cause irreversible damage to the hardware. Moreover, abrupt changes in task-space contact velocity and peak impact forces also result in abrupt changes in robot joint velocities and torques; which can compromise controllers' stability, especially for those based on smooth models. In reality, several tasks would require establishing contact with moderately high velocity. We propose to enhance task-space multi-objective controllers formulated as a quadratic program to be resilient to frictional impacts in three dimensions. We devise new constraints and reformulate the usual ones to be robust to the abrupt joint state changes mentioned earlier. The impact event becomes a controlled process once the optimal control search space is aware of: (1) the hardware-affordable impact bounds and (2) analytically-computed feasible set (polyhedra) that constrain post-impact critical states. Prior to and nearby the targeted contact spot, we assume, at each control cycle, that the impact will occur at the next iteration. This somewhat one-step preview makes our controller robust to impact time and location. To assess our approach, we experimented its resilience to moderate impacts with the Panda manipulator and achieved swift grabbing tasks with the HRP-4 humanoid robot.
A fast and accurate physics-informed neural network reduced order model with shallow masked autoencoder
Creators: name: Kim, Youngkyu
name: Choi, Youngsoo
name: Widemann, David
name: Zohdi, Tarek
Publisher: name: arXiv
Year: 2020
Subjects: subject: Numerical Analysis (math.NA)
subject: Machine Learning (cs.LG)
subject: Neural and Evolutionary Computing (cs.NE)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: Traditional linear subspace reduced order models (LS-ROMs) are able to accelerate physical simulations, in which the intrinsic solution space falls into a subspace with a small dimension, i.e., the solution space has a small Kolmogorov n-width. However, for physical phenomena not of this type, e.g., any advection-dominated flow phenomena, such as in traffic flow, atmospheric flows, and air flow over vehicles, a low-dimensional linear subspace poorly approximates the solution. To address cases such as these, we have developed a fast and accurate physics-informed neural network ROM, namely nonlinear manifold ROM (NM-ROM), which can better approximate high-fidelity model solutions with a smaller latent space dimension than the LS-ROMs. Our method takes advantage of the existing numerical methods that are used to solve the corresponding full order models. The efficiency is achieved by developing a hyper-reduction technique in the context of the NM-ROM. Numerical results show that neural networks can learn a more efficient latent space representation on advection-dominated data from 1D and 2D Burgers' equations. A speedup of up to 2.6 for 1D Burgers' and a speedup of 11.7 for 2D Burgers' equations are achieved with an appropriate treatment of the nonlinear terms through a hyper-reduction technique. Finally, a posteriori error bounds for the NM-ROMs are derived that take account of the hyper-reduced operators.
description: 33 pages, 17 figures
Geometry of Sample Spaces
Creators: name: Harms, Philipp
name: Michor, Peter W.
name: Pennec, Xavier
name: Sommer, Stefan
Publisher: name: arXiv
Year: 2020
Subjects: subject: Statistics Theory (math.ST)
subject: Metric Geometry (math.MG)
subject: FOS: Mathematics
subject: 62R20, 62R30 (Primary) 62F12 (Secondary)

description: In statistics, independent, identically distributed random samples do not carry a natural ordering, and their statistics are typically invariant with respect to permutations of their order. Thus, an $n$-sample in a space $M$ can be considered as an element of the quotient space of $M^n$ modulo the permutation group. The present paper takes this definition of sample space and the related concept of orbit types as a starting point for developing a geometric perspective on statistics. We aim at deriving a general mathematical setting for studying the behavior of empirical and population means in spaces ranging from smooth Riemannian manifolds to general stratified spaces. We fully describe the orbifold and path-metric structure of the sample space when $M$ is a manifold or path-metric space, respectively. These results are non-trivial even when $M$ is Euclidean. We show that the infinite sample space exists in a Gromov-Hausdorff type sense and coincides with the Wasserstein space of probability distributions on $M$. We exhibit Fréchet means and $k$-means as metric projections onto 1-skeleta or $k$-skeleta in Wasserstein space, and we define a new and more general notion of polymeans. This geometric characterization via metric projections applies equally to sample and population means, and we use it to establish asymptotic properties of polymeans such as consistency and asymptotic normality.
description: 31 pages, 1 figure
Field-induced quantum critical point in the new itinerant antiferromagnet Ti$_3$Cu$_4$
Creators: name: Moya, Jaime M.
name: Hallas, Alannah M.
name: Loganathan, Vaideesh
name: Huang, C. -L.
name: Kish, Lazar
name: Aczel, Adam A.
name: Beare, J.
name: Cai, Y.
name: Luke, G. M.
name: Weickert, Franziska
name: Nevidomskyy, Andriy H.
name: Malliakas, Christos D.
name: Kanatzidis, Mercouri G.
name: Lei, Shiming
name: Bayliff, Kyle
name: Morosan, E.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: New phases of matter emerge at the edge of magnetic instabilities. In local moment systems, such as heavy fermions, the magnetism can be destabilized by pressure, chemical doping, and, rarely, by magnetic field, towards a zero-temperature transition at a quantum critical point (QCP). Even more rare are instances of QCPs induced by pressure or doping in itinerant moment systems, with no known examples of analogous field-induced \textit{T} = 0 transitions. Here we report the discovery of a new itinerant antiferromagnet with no magnetic constituents, in single crystals of Ti$_3$Cu$_4$ with $T_N$ = 11.3 K. Band structure calculations point to an orbital-selective, spin density wave ground state, a consequence of the square net structural motif in Ti$_3$Cu$_4$. A small magnetic field, $H_C$ = 4.87 T, suppresses the long-range order via a continuous second-order transition, resulting in a field-induced QCP. The magnetic Grüneisen ratio diverges as $H \rightarrow H_C$ and $T\rightarrow0$, with a sign change at $H_C$ and $T^{-1}$ scaling at $H~=~H_C$, providing evidence from thermodynamic measurements for quantum criticality for $H \parallel c$. Non-Fermi liquid (NFL) to Fermi liquid (FL) crossover is observed close to the QCP, as revealed by the power law behavior of the electrical resistivity.
Combinatorial Bounds in Distal Structures
Creators: name: Anderson, Aaron
Publisher: name: arXiv
Year: 2021
Subjects: subject: Logic (math.LO)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 03C45 (Primary), 03C64, 05C35 (Secondary)

description: We provide polynomial upper bounds for the minimal sizes of distal cell decompositions in several kinds of distal structures, particularly weakly $o$-minimal and $P$-minimal structures. The bound in general weakly $o$-minimal structures generalizes the vertical cell decomposition for semialgebraic sets, and the bounds for vector spaces in both $o$-minimal and $p$-adic cases are tight. We apply these bounds to Zarankiewicz's problem and sum-product bounds in distal structures.
Piecewise orthogonal collocation for computing periodic solutions of renewal equations
Creators: name: Ando', Alessia
name: Breda, Dimitri
Publisher: name: arXiv
Year: 2021
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics
subject: 65L03, 65L10, 65L20, 65L60, 92D25

description: We extend the use of piecewise orthogonal collocation to computing periodic solutions of renewal equations, which are particularly important in modeling population dynamics. We prove convergence through a rigorous error analysis. Finally, we show some numerical experiments confirming the theoretical results, and a couple of applications in view of bifurcation analysis.
description: 32 pages, 6 figures
Meta-learning Amidst Heterogeneity and Ambiguity
Creators: name: Go, Kyeongryeol
name: Yun, Seyoung
Publisher: name: arXiv
Year: 2021
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Meta-learning aims to learn a model that can handle multiple tasks generated from an unknown but shared distribution. However, typical meta-learning algorithms have assumed the tasks to be similar such that a single meta-learner is sufficient to aggregate the variations in all aspects. In addition, there has been less consideration on uncertainty when limited information is given as context. In this paper, we devise a novel meta-learning framework, called Meta-learning Amidst Heterogeneity and Ambiguity (MAHA), that outperforms previous works in terms of prediction based on its ability on task identification. By extensively conducting several experiments in regression and classification, we demonstrate the validity of our model, which turns out to be robust to both task heterogeneity and ambiguity.
Deformations of categories of coherent sheaves via quivers with relations
Creators: name: Barmeier, Severin
name: Wang, Zhengfang
Publisher: name: arXiv
Year: 2021
Subjects: subject: Algebraic Geometry (math.AG)
subject: Quantum Algebra (math.QA)
subject: FOS: Mathematics
subject: 18E10, 14A22, 16S80, 14B07

description: We give an explicit combinatorial description of the deformation theory of the Abelian category of (quasi)coherent sheaves on any separated Noetherian scheme $X$ via the deformation theory of path algebras of quivers with relations, by using any affine open cover of $X$, or any tilting bundle on $X$, if available.
 We also give sufficient criteria for obtaining algebraizations of formal deformations, in which case the deformation parameters can be evaluated to a constant and the deformations can be compared to the original Abelian category on equal terms. We give concrete examples as well as applications to the study of noncommutative deformations of singularities.
description: 35 pages, final version to appear in Algebraic Geometry
Dissipative Edge Transport in Disordered Axion Insulator Films
Creators: name: Liu, Zhaochen
name: Qian, Dongheng
name: Jiang, Yadong
name: Wang, Jing
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We investigate the role of disorder in the edge transport of axion insulator films. We predict by first-principles calculations that even-number-layer MnBi$_2$Te$_4$ have gapped helical edge states. The random potential will dramatically modify the edge spectral function to become gapless. However, such gapless helical state here is fundamentally different from that in quantum spin Hall insulator or topological Anderson insulator. We further study the edge transport in this system by Landauer-Büttiker formalism, and find such gapless edge state is dissipative and not immune to backscattering, which would explain the dissipative nonlocal transport in the axion insulator state observed in six septuple layer MnBi$_2$Te$_4$ experimentally. Several transport experiments are proposed to verify our theory on the dissipative helical edge channels. In particular, the longitudinal resistance can be greatly reduced by adding an extra floating probe even if it is not used. These results will facilitate the observsation of long-sought topological magnetoelectric effect in axion insulators.
description: 7pages,4 figures
Singular equivalences to locally coherent hearts of commutative noetherian rings
Creators: name: Hrbek, Michal
name: Pavon, Sergio
Publisher: name: arXiv
Year: 2021
Subjects: subject: Commutative Algebra (math.AC)
subject: Representation Theory (math.RT)
subject: FOS: Mathematics
subject: 13E05, 18G10 (Primary) 14F08 (Secondary)

description: We show that Krause's recollement exists for any locally coherent Grothendieck category such that its derived category is compactly generated. As a source of such categories, we consider the hearts of intermediate and restrictable $t$-structures in the derived category of a commutative noetherian ring. We show that the induced tilting object over such a heart gives rise to an equivalence between the two Krause's recollements, and in particular, to a singular equivalence.
description: 25 pages, some extra material added, exposition improved
Integrating Quantum Processor Device and Control Optimization in a Gradient-based Framework
Creators: name: Ni, Xiaotong
name: Zhao, Hui-Hai
name: Wang, Lei
name: Wu, Feng
name: Chen, Jianxin
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Machine Learning (cs.LG)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: In a quantum processor, the device design and external controls together contribute to the quality of the target quantum operations. As we continuously seek better alternative qubit platforms, we explore the increasingly large device and control design space. Thus, optimization becomes more and more challenging. In this work, we demonstrate that the figure of merit reflecting a design goal can be made differentiable with respect to the device and control parameters. In addition, we can compute the gradient of the design objective efficiently in a similar manner to the back-propagation algorithm and then utilize the gradient to optimize the device and the control parameters jointly and efficiently. This extends the scope of the quantum optimal control to superconducting device design. We also demonstrate the viability of gradient-based joint optimization over the device and control parameters through a few examples.
A Point-free Perspective on Lax extensions and Predicate liftings
Creators: name: Goncharov, Sergey
name: Hofmann, Dirk
name: Nora, Pedro
name: Schröder, Lutz
name: Wild, Paul
Publisher: name: arXiv
Year: 2021
Subjects: subject: Category Theory (math.CT)
subject: Logic in Computer Science (cs.LO)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: Lax extensions of set functors play a key role in various areas including topology, concurrent systems, and modal logic, while predicate liftings provide a generic semantics of modal operators. We take a fresh look at the connection between lax extensions and predicate liftings from the point of view of quantale-enriched relations. Using this perspective, we show in particular that various fundamental concepts and results arise naturally and their proofs become very elementary. Ultimately, we prove that every lax extension is induced by a class of predicate liftings; we discuss several implications of this result.
MIMICA V5.1: a user guide
Creators: name: Savre, Julien
name: Brakebusch, Matthias
Publisher: name: Zenodo
Year: 2022
Subjects: Software documentation
Large-Eddy Simulation
Atmospheric model

description: This document introduces the MISU-MIT Cloud and Aerosol (MIMICA) model, an area-limited, three-dimensional high-resolution numerical model dedicated to the simulation of clouds and other atmospheric processes. The document contains a detailed description of the code and algorithms, as well as an extended section serving as a user manual for new and experienced users.
Integrability and geometry of the Wynn recurrence
Creators: name: Doliwa, Adam
name: Siemaszko, Artur
Publisher: name: arXiv
Year: 2022
Subjects: subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: Numerical Analysis (math.NA)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We show that the Wynn recurrence (the missing identity of Frobenius of the Padé approximation theory) can be incorporated into the theory of integrable systems as a reduction of the discrete Schwarzian Kadomtsev-Petviashvili equation. This allows, in particular, to present the geometric meaning of the recurrence as a construction of the appropriately constrained quadrangular set of points. The interpretation is valid for a projective line over arbitrary skew field what motivates to consider non-commutative Padé theory. We transfer the corresponding elements, including the Frobenius identities, to the non-commutative level using the quasideterminants. Using an example of the characteristic series of the Fibonacci language we present an application of the theory to the regular languages. We introduce the non-commutative version of the discrete-time Toda lattice equations together with their integrability structure. Finally, we discuss application of the Wynn recurrence in a different context of the geometric theory of discrete analytic functions.
description: 17 pages, 7 figures; v2 presentation improved +2 pages