cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Politigram: Leftist Political Instagram and Horizons of Knowledge
Creators: name: Jahn, Alfredo
Publisher: name: University of Chicago
Year: 2020
Subjects: subject: Politics
subject: affect
subject: Deleuze
subject: Bourdieu
subject: Instagram
subject: Leftism
subject: python

description: This paper considers how the structure of Instagram and social norms on the app constitute a landscape that restricts and amplifies the flows of certain informational forms — what I term the knowledge landscape. Instagram’s knowledge landscape selects for certain ideas to proliferate across the app, leading to particular significatory and affective encounters with ideas and unique sedimentations of knowledge. To understand how the knowledge landscape influences encounters with political ideas, I analyze follower network and digital engagement data across 127 accounts and several hundred posts from “Politigram”, a loose space of activist, advocacy, meme, and ‘shitpost’ accounts engaging in left-leaning politics. Using interviews with six users and five content creators on Politigram, I explore how the space is understood by those who use it, what motivates users to engage with various content, and what engagement habits emerge. These factors reveal the topologies of the knowledge landscape that influence the flows of information through the space. Finally, I consider the processes by which the knowledge landscape reconfigures information through memeification. This paper critiques the notion that Instagram, or any media platform, can serve as a neutral ground for advocacy and education to new audiences. The possibilities of engagement are restricted by the knowledge landscape, eliciting certain behaviors from users, constricting the range of idea encounters, and producing knowledge that is qualitatively distinct from that which is encountered elsewhere.
On atomic structure of Ge huts growing on the Ge/Si(001) wetting layer
Creators: name: Arapkina, Larisa V.
name: Yuryev, Vladimir A.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Structural models of growing Ge hut clusters---pyramids and wedges---are proposed on the basis of data of recent STM investigations of nucleation and growth of Ge huts on the Si(001) surface in the process of molecular beam epitaxy. It is shown that extension of a hut base along <110> directions goes non-uniformly during the cluster growth regardless of its shape. Growing pyramids, starting from the second monolayer, pass through cyclic formation of slightly asymmetrical and symmetrical clusters, with symmetrical ones appearing after addition of every fourth terrace. We suppose that only symmetrical configurations of pyramids composed by 2, 6, 10, 14, etc. monolayers over the wetting layer are stable. This might explain less stability of pyramids in comparison with wedges in dense arrays obtained at low Ge deposition temperatures. Possible nucleation processes of pyramids and wedges on wetting layer patches from identical embryos composed by 8 dimers through formation of 1 monolayer high 16-dimer nuclei different only in their symmetry is discussed. Schematics of these processes are presented for both species of huts. It is concluded from precise STM measurements that top layers of WL patches are relaxed when huts nucleate on them.
description: 20 pages, 9 figures
Assessing the Impact of COVID-19 on the Objective and Analysis of Oncology Clinical Trials -- Application of the Estimand Framework
Creators: name: Degtyarev, Evgeny
name: Rufibach, Kaspar
name: Shentu, Yue
name: Yung, Godwin
name: Casey, Michelle
name: Englert, Stefan
name: Liu, Feng
name: Liu, Yi
name: Sailer, Oliver
name: Siegel, Jonathan
name: Sun, Steven
name: Tang, Rui
name: Zhou, Jiangxiu
Publisher: name: arXiv
Year: 2020
Subjects: subject: Other Quantitative Biology (q-bio.OT)
subject: FOS: Biological sciences

description: COVID-19 outbreak has rapidly evolved into a global pandemic. The impact of COVID-19 on patient journeys in oncology represents a new risk to interpretation of trial results and its broad applicability for future clinical practice. We identify key intercurrent events that may occur due to COVID-19 in oncology clinical trials with a focus on time-to-event endpoints and discuss considerations pertaining to the other estimand attributes introduced in the ICH E9 addendum. We propose strategies to handle COVID-19 related intercurrent events, depending on their relationship with malignancy and treatment and the interpretability of data after them. We argue that the clinical trial objective from a world without COVID-19 pandemic remains valid. The estimand framework provides a common language to discuss the impact of COVID-19 in a structured and transparent manner. This demonstrates that the applicability of the framework may even go beyond what it was initially intended for.
description: Paper written on behalf of the industry working group on estimands in oncology (www.oncoestimand.org). Accepted for publication in a special issue of Statistics in Biopharmaceutical Research
Digital Quantum Simulation of the Holstein Model in Trapped Ions
Creators: name: Mezzacapo, A.
name: Casanova, J.
name: Lamata, L.
name: Solano, E.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We propose the implementation of the Holstein model by means of digital methods in a linear chain of trapped ions. We show how the simulation fidelity scales with the generation of phononic excitations. We propose a decomposition and a stepwise trapped-ion implementation of the Holstein Hamiltonian. Via numerical simulations, we study how the protocol is affected by realistic gates. Finally, we show how measurements of the size of the simulated polaron can be performed.
description: 5 pages + supplemental material, 3+3 figures. Accepted in Physical Review Letters
Human Trust-based Feedback Control: Dynamically varying automation transparency to optimize human-machine interactions
Creators: name: Akash, Kumar
name: McMahon, Griffon
name: Reid, Tahira
name: Jain, Neera
Publisher: name: arXiv
Year: 2020
Subjects: subject: Human-Computer Interaction (cs.HC)
subject: Robotics (cs.RO)
subject: Systems and Control (eess.SY)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: H.1.2; H.5

description: Human trust in automation plays an essential role in interactions between humans and automation. While a lack of trust can lead to a human's disuse of automation, over-trust can result in a human trusting a faulty autonomous system which could have negative consequences for the human. Therefore, human trust should be calibrated to optimize human-machine interactions with respect to context-specific performance objectives. In this article, we present a probabilistic framework to model and calibrate a human's trust and workload dynamics during his/her interaction with an intelligent decision-aid system. This calibration is achieved by varying the automation's transparency---the amount and utility of information provided to the human. The parameterization of the model is conducted using behavioral data collected through human-subject experiments, and three feedback control policies are experimentally validated and compared against a non-adaptive decision-aid system. The results show that human-automation team performance can be optimized when the transparency is dynamically updated based on the proposed control policy. This framework is a first step toward widespread design and implementation of real-time adaptive automation for use in human-machine interactions.
description: 21 pages
Gapless spin-liquid phase in the kagome spin-1/2 Heisenberg antiferromagnet
Creators: name: Iqbal, Yasir
name: Becca, Federico
name: Sorella, Sandro
name: Poilblanc, Didier
Publisher: name: arXiv
Year: 2012
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study the energy and the static spin structure factor of the ground state of the spin-1/2 quantum Heisenberg antiferromagnetic model on the kagome lattice. By the iterative application of a few Lanczos steps on accurate projected fermionic wave functions and the Green's function Monte Carlo technique, we find that a gapless (algebraic) U(1) Dirac spin liquid is competitive with previously proposed gapped (topological) Z2 spin liquids. By performing a finite-size extrapolation of the ground-state energy, we obtain an energy per site E/J=-0.4365(2), which is equal, within three error bars, to the estimates given by the density-matrix renormalization group (DMRG). Our estimate is obtained for a translationally invariant system, and, therefore, does not suffer from boundary effects, like in DMRG. Moreover, on finite toric clusters at the pure variational level, our energies are lower compared to those from DMRG calculations.
description: Final published version. Main Paper (6 pages, 4 figures, 1 table) + Supplementary Material (4 pages, 8 figures)
Effect of charged particle's multiplicity fluctuations on flow harmonics in even-by-event hydrodynamics
Creators: name: Chaudhuri, A. K.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In nucleon-nucleon collisions, charged particle's multiplicity fluctuates. We have studied the effect of multiplicity fluctuation on flow harmonics in nucleus-nucleus collision in event-by-event hydrodynamics. Assuming that the charged particle's multiplicity fluctuations are governed by the negative binomial distribution, the Monte-Carlo Glauber model of initial condition is generalised to include the fluctuations. Explicit simulations with the generalised Monte-Carlo Glauber model initial conditions indicate that the multiplicity fluctuations do not have large effect on the flow harmonics.
description: 8 pages, 8 figures. Final version to be published in Physical Review C. arXiv admin note: text overlap with arXiv:1204.2986
Pro cdh-descent for cyclic homology and $K$-theory
Creators: name: Morrow, Matthew
Publisher: name: arXiv
Year: 2012
Subjects: subject: K-Theory and Homology (math.KT)
subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics

description: In this paper we prove that cyclic homology, topological cyclic homology, and algebraic $K$-theory satisfy a pro Mayer--Vietoris property with respect to abstract blow-up squares of varieties, in both zero and finite characteristic. This may be interpreted as the well-definedness of $K$-theory with compact support.
description: This is a substantial replacement of the earlier version, whose contents have been expanded and divided into three disjoint papers: arXiv:1404.4179, the current paper, and arXiv:1404.4649. In particular, the proof of pro cdh-descent of $K$-theory has been extended to finite characteristic
Disorder effects on the static scattering function of star branched polymers
Creators: name: Blavatska, V.
name: von Ferber, C.
name: Holovatch, Yu.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: We present an analysis of the impact of structural disorder on the static scattering function of f-armed star branched polymers in d dimensions. To this end, we consider the model of a star polymer immersed in a good solvent in the presence of structural defects, correlated at large distances r according to a power law \sim r^{-a}. In particular, we are interested in the ratio g(f) of the radii of gyration of star and linear polymers of the same molecular weight, which is a universal experimentally measurable quantity. We apply a direct polymer renormalization approach and evaluate the results within the double \varepsilon=4-d, δ=4-a-expansion. We find an increase of g(f) with an increasing δ. Therefore, an increase of disorder correlations leads to an increase of the size measure of a star relative to linear polymers of the same molecular weight.
description: 17 pages, 7 figures
A review of Bayesian perspectives on sample size derivation for confirmatory trials
Creators: name: Kunzmann, Kevin
name: Grayling, Michael J.
name: Lee, Kim May
name: Robertson, David S.
name: Rufibach, Kaspar
name: Wason, James M. S.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Applications (stat.AP)
subject: FOS: Computer and information sciences

description: Sample size derivation is a crucial element of the planning phase of any confirmatory trial. A sample size is typically derived based on constraints on the maximal acceptable type I error rate and a minimal desired power. Here, power depends on the unknown true effect size. In practice, power is typically calculated either for the smallest relevant effect size or a likely point alternative. The former might be problematic if the minimal relevant effect is close to the null, thus requiring an excessively large sample size. The latter is dubious since it does not account for the a priori uncertainty about the likely alternative effect size. A Bayesian perspective on the sample size derivation for a frequentist trial naturally emerges as a way of reconciling arguments about the relative a priori plausibility of alternative effect sizes with ideas based on the relevance of effect sizes. Many suggestions as to how such `hybrid' approaches could be implemented in practice have been put forward in the literature. However, key quantities such as assurance, probability of success, or expected power are often defined in subtly different ways in the literature. Starting from the traditional and entirely frequentist approach to sample size derivation, we derive consistent definitions for the most commonly used `hybrid' quantities and highlight connections, before discussing and demonstrating their use in the context of sample size derivation for clinical trials.
Positive logics
Creators: name: Shelah, Saharon
name: Väänänen, Jouko
Publisher: name: arXiv
Year: 2020
Subjects: subject: Logic (math.LO)
subject: FOS: Mathematics
subject: 03C95

description: Lindström's Theorem characterizes first order logic as the maximal logic satisfying the Compactness Theorem and the Downward Löwenheim-Skolem Theorem. If we do not assume that logics are closed under negation, there is an obvious extension of first order logic with the two model theoretic properties mentioned, namely existential second order logic. We show that existential second order logic has a whole family of proper extensions satisfying the Compactness Theorem and the Downward Löwenheim-Skolem Theorem. Furthermore, we show that in the context of negationless logics, positive logics, as we call them, there is no strongest extension of first order logic with the Compactness Theorem and the Downward Löwenheim-Skolem Theorem.
Principal Stratum Strategy: Potential Role in Drug Development
Creators: name: Bornkamp, Björn
name: Rufibach, Kaspar
name: Lin, Jianchang
name: Liu, Yi
name: Mehrotra, Devan V.
name: Roychoudhury, Satrajit
name: Schmidli, Heinz
name: Shentu, Yue
name: Wolbers, Marcel
Publisher: name: arXiv
Year: 2020
Subjects: subject: Applications (stat.AP)
subject: FOS: Computer and information sciences

description: A randomized trial allows estimation of the causal effect of an intervention compared to a control in the overall population and in subpopulations defined by baseline characteristics. Often, however, clinical questions also arise regarding the treatment effect in subpopulations of patients, which would experience clinical or disease related events post-randomization. Events that occur after treatment initiation and potentially affect the interpretation or the existence of the measurements are called {\it intercurrent events} in the ICH E9(R1) guideline. If the intercurrent event is a consequence of treatment, randomization alone is no longer sufficient to meaningfully estimate the treatment effect. Analyses comparing the subgroups of patients without the intercurrent events for intervention and control will not estimate a causal effect. This is well known, but post-hoc analyses of this kind are commonly performed in drug development. An alternative approach is the principal stratum strategy, which classifies subjects according to their potential occurrence of an intercurrent event on both study arms. We illustrate with examples that questions formulated through principal strata occur naturally in drug development and argue that approaching these questions with the ICH E9(R1) estimand framework has the potential to lead to more transparent assumptions as well as more adequate analyses and conclusions. In addition, we provide an overview of assumptions required for estimation of effects in principal strata. Most of these assumptions are unverifiable and should hence be based on solid scientific understanding. Sensitivity analyses are needed to assess robustness of conclusions.
Survival analysis for AdVerse events with VarYing follow-up times (SAVVY) -- estimation of adverse event risks
Creators: name: Stegherr, Regina
name: Schmoor, Claudia
name: Beyersmann, Jan
name: Rufibach, Kaspar
name: Jehl, Valentine
name: Brückner, Andreas
name: Eisele, Lewin
name: Künzel, Thomas
name: Kupas, Katrin
name: Langer, Frank
name: Leverkus, Friedhelm
name: Loos, Anja
name: Norenberg, Christiane
name: Voss, Florian
name: Friede, Tim
Publisher: name: arXiv
Year: 2020
Subjects: subject: Applications (stat.AP)
subject: FOS: Computer and information sciences

description: The SAVVY project aims to improve the analyses of adverse event (AE) data in clinical trials through the use of survival techniques appropriately dealing with varying follow-up times and competing events (CEs). Although statistical methodologies have advanced, in AE analyses often the incidence proportion, the incidence density, or a non-parametric Kaplan-Meier estimator (KME) are used, which either ignore censoring or CEs. In an empirical study including randomized clinical trials from several sponsor organisations, these potential sources of bias are investigated. The main aim is to compare the estimators that are typically used in AE analysis to the Aalen-Johansen estimator (AJE) as the gold-standard. Here, one-sample findings are reported, while a companion paper considers consequences when comparing treatment groups. Estimators are compared with descriptive statistics, graphical displays and with a random effects meta-analysis. The influence of different factors on the size of the bias is investigated in a meta-regression. Comparisons are conducted at the maximum follow-up time and at earlier evaluation time points. CEs definition does not only include death before AE but also end of follow-up for AEs due to events possibly related to the disease course or the treatment. Ten sponsor organisations provided 17 trials including 186 types of AEs. The one minus KME was on average about 1.2-fold larger than the AJE. Leading forces influencing bias were the amount of censoring and of CEs. As a consequence, the average bias using the incidence proportion was less than 5%. Assuming constant hazards using incidence densities was hardly an issue provided that CEs were accounted for. There is a need to improve the guidelines of reporting risks of AEs so that the KME and the incidence proportion are replaced by the AJE with an appropriate definition of CEs.
Evidence for a direct band gap in the topological insulator Bi2Se3 from theory and experiment
Creators: name: Nechaev, I. A.
name: Hatch, R. C.
name: Bianchi, M.
name: Guan, D.
name: Friedrich, C.
name: Aguilera, I.
name: Mi, J. L.
name: Iversen, B. B.
name: Blügel, S.
name: Hofmann, Ph.
name: Chulkov, E. V.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Using angle-resolved photoelectron spectroscopy and ab-initio GW calculations, we unambiguously show that the widely investigated three-dimensional topological insulator Bi2Se3 has a direct band gap at the Gamma point. Experimentally, this is shown by a three-dimensional band mapping in large fractions of the Brillouin zone. Theoretically, we demonstrate that the valence band maximum is located at the Brillouin center only if many-body effects are included in the calculation. Otherwise, it is found in a high-symmetry mirror plane away from the zone center.
description: 8 pages, 4 figures
Survival analysis for AdVerse events with VarYing follow-up times (SAVVY) -- comparison of adverse event risks in randomized controlled trials
Creators: name: Rufibach, Kaspar
name: Stegherr, Regina
name: Schmoor, Claudia
name: Jehl, Valentine
name: Allignol, Arthur
name: Boeckenhoff, Annette
name: Dunger-Baldauf, Cornelia
name: Eisele, Lewin
name: Künzel, Thomas
name: Kupas, Katrin
name: Leverkus, Friedhelm
name: Trampisch, Matthias
name: Zhao, Yumin
name: Friede, Tim
name: Beyersmann, Jan
Publisher: name: arXiv
Year: 2020
Subjects: subject: Applications (stat.AP)
subject: FOS: Computer and information sciences

description: Analyses of adverse events (AEs) are an important aspect of the evaluation of experimental therapies. The SAVVY (Survival analysis for AdVerse events with Varying follow-up times) project aims to improve the analyses of AE data in clinical trials through the use of survival techniques appropriately dealing with varying follow-up times, censoring, and competing events (CE). In an empirical study including seventeen randomized clinical trials the effect of varying follow-up times, censoring, and competing events on comparisons of two treatment arms with respect to AE risks is investigated. The comparisons of relative risks (RR) of standard probability-based estimators to the gold-standard Aalen-Johansen estimator or hazard-based estimators to an estimated hazard ratio (HR) from Cox regression are done descriptively, with graphical displays, and using a random effects meta-analysis on AE level. The influence of different factors on the size of the bias is investigated in a meta-regression. We find that for both, avoiding bias and categorization of evidence with respect to treatment effect on AE risk into categories, the choice of the estimator is key and more important than features of the underlying data such as percentage of censoring, CEs, amount of follow-up, or value of the gold-standard RR. There is an urgent need to improve the guidelines of reporting AEs so that incidence proportions are finally replaced by the Aalen-Johansen estimator - rather than by Kaplan-Meier - with appropriate definition of CEs. For RRs based on hazards, the HR based on Cox regression has better properties than the ratio of incidence densities.
Near-Quadratic Lower Bounds for Two-Pass Graph Streaming Algorithms
Creators: name: Assadi, Sepehr
name: Raz, Ran
Publisher: name: arXiv
Year: 2020
Subjects: subject: Data Structures and Algorithms (cs.DS)
subject: Computational Complexity (cs.CC)
subject: FOS: Computer and information sciences

description: We prove that any two-pass graph streaming algorithm for the $s$-$t$ reachability problem in $n$-vertex directed graphs requires near-quadratic space of $n^{2-o(1)}$ bits. As a corollary, we also obtain near-quadratic space lower bounds for several other fundamental problems including maximum bipartite matching and (approximate) shortest path in undirected graphs. Our results collectively imply that a wide range of graph problems admit essentially no non-trivial streaming algorithm even when two passes over the input is allowed. Prior to our work, such impossibility results were only known for single-pass streaming algorithms, and the best two-pass lower bounds only ruled out $o(n^{7/6})$ space algorithms, leaving open a large gap between (trivial) upper bounds and lower bounds.
Holonomic functions of several complex variables and singularities of anisotropic Ising n-fold integrals
Creators: name: Boukraa, S.
name: Hassani, S.
name: Maillard, J-M.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Mathematical Physics (math-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences
subject: 34M55, 47E05, 81Qxx, 32G34, 34Lxx, 34Mxx, 14Kxx

description: Lattice statistical mechanics, often provides a natural (holonomic) framework to perform singularity analysis with several complex variables that would, in a general mathematical framework, be too complex, or could not be defined. Considering several Picard-Fuchs systems of two-variables "above" Calabi-Yau ODEs, associated with double hypergeometric series, we show that holonomic functions are actually a good framework for actually finding the singular manifolds. We, then, analyse the singular algebraic varieties of the n-fold integrals $ χ^{(n)}$, corresponding to the decomposition of the magnetic susceptibility of the anisotropic square Ising model. We revisit a set of Nickelian singularities that turns out to be a two-parameter family of elliptic curves. We then find a first set of non-Nickelian singularities for $ χ^{(3)}$ and $ χ^{(4)}$, that also turns out to be rational or ellipic curves. We underline the fact that these singular curves depend on the anisotropy of the Ising model. We address, from a birational viewpoint, the emergence of families of elliptic curves, and of Calabi-Yau manifolds on such problems. We discuss the accumulation of these singular curves for the non-holonomic anisotropic full susceptibility.
description: 36 pages
Toward Adaptive Trust Calibration for Level 2 Driving Automation
Creators: name: Akash, Kumar
name: Jain, Neera
name: Misu, Teruhisa
Publisher: name: arXiv
Year: 2020
Subjects: subject: Human-Computer Interaction (cs.HC)
subject: Robotics (cs.RO)
subject: Systems and Control (eess.SY)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Properly calibrated human trust is essential for successful interaction between humans and automation. However, while human trust calibration can be improved by increased automation transparency, too much transparency can overwhelm human workload. To address this tradeoff, we present a probabilistic framework using a partially observable Markov decision process (POMDP) for modeling the coupled trust-workload dynamics of human behavior in an action-automation context. We specifically consider hands-off Level 2 driving automation in a city environment involving multiple intersections where the human chooses whether or not to rely on the automation. We consider automation reliability, automation transparency, and scene complexity, along with human reliance and eye-gaze behavior, to model the dynamics of human trust and workload. We demonstrate that our model framework can appropriately vary automation transparency based on real-time human trust and workload belief estimates to achieve trust calibration.
description: 10 pages, 8 figures
Many-body energy localization transition in periodically driven systems
Creators: name: D'Alessio, Luca
name: Polkovnikov, Anatoli
Publisher: name: arXiv
Year: 2012
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: According to the second law of thermodynamics the total entropy of a system is increased during almost any dynamical process. The positivity of the specific heat implies that the entropy increase is associated with heating. This is generally true both at the single particle level, like in the Fermi acceleration mechanism of charged particles reflected by magnetic mirrors, and for complex systems in everyday devices. Notable exceptions are known in noninteracting systems of particles moving in periodic potentials. Here the phenomenon of dynamical localization can prevent heating beyond certain threshold. The dynamical localization is known to occur both at classical (Fermi-Ulam model) and at quantum levels (kicked rotor). However, it was believed that driven ergodic systems will always heat without bound. Here, on the contrary, we report strong evidence of dynamical localization transition in periodically driven ergodic systems in the thermodynamic limit. This phenomenon is reminiscent of many-body localization in energy space.
description: final (printed) version
The flat-sky approximation to galaxy number counts -- redshift space correlation function
Creators: name: Jelic-Cizmek, Goran
Publisher: name: arXiv
Year: 2020
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We study the flat-sky approximation for galaxy number counts including relativistic effects, and assess its performance and accuracy with respect to the full-sky result. We find an agreement of up to 5% for the local and lensing contributions to the 2-point correlation function and its multipoles at $z > 0.5$, and up to 1% for the multipoles alone at $z > 1$ and separations $\lesssim 250$ Mpc/$h$, with a speed-up of over a factor of 1000. Using a semi-analytic method, which has been implemented in a new version of the code COFFE, along with the Limber approximation for the integrated contributions, we further increase the performance, allowing the computation of the flat-sky multipoles to be done over 10000 times faster than in the full-sky calculation, which could be used to greatly speed-up Markov chain Monte Carlo sampling for cosmological parameter estimation.
description: 32 pages, 8 figures. Fixed missing factor of 2 in density-lensing eq. (2.15). Code available at https://github.com/JCGoran/coffe
Plaquette-RVB state in the Frustrated Honeycomb Antiferromagnet
Creators: name: Ganesh, R.
name: Nishimoto, Satoshi
name: Brink, Jeroen van den
Publisher: name: arXiv
Year: 2012
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We study the proposed plaquette-RVB (pRVB) state in the honeycomb lattice $J_1-J_2$ model with frustration arising from next-nearest neighbour interactions. Starting with the limit of decoupled hexagons, we develop a plaquette operator approach to describe the pRVB state and its low energy excitations. Our calculation clarifies that the putative pRVB state necessarily has f-wave symmetry - the plaquette wavefunction is an antisymmetric combination of the Kekulé structures. We estimate the plaquette ordering amplitude, ground state energy and spin gap as a function of $J_2/J_1$. The pRVB state is most stable around $J_2/J_1 \sim 0.25$. We identify the wavevectors of the lowest triplet excitations, which can be verified using exact diagonalization or DMRG studies. When $J_2$ is reduced, we can have either a deconfined Quantum Phase Transition (QPT) or a first-order transition into a Néel state. When $J_2$ is increased, we surmise that the system undergoes a first order phase transition into a state which breaks lattice rotational symmetry.
description: 9 pages, 9 figures, minor corrections
«Vogliatemi bene»: lettere di Matilde Serao a Gabriele d’Annunzio
Creators: name: Trevisan, Alessandra
Publisher: name: Fondazione Università Ca’ Foscari Venezia, Italia
Year: 2019

description:

Between ca. 1885 and 1927, Gabriele d’Annunzio and Matilde Serao became friends and contributed to journals in Rome and Naples; they met authors in Europe (especially in France), exchanged opinions about their works and also about their private life. She has been a vibrant constant on Vate’s experience: she gave him advices and protected his affair with Eleonora Duse, who was also Matilde’s friend. Serao’s collection of letters, kept by Fondazione Il Vittoriale degli Italiani in Gardone Riviera, explains some contours of a crucial friendship.

description: Archivio d’Annunzio
p/pi Ratio in Di-Hadron Correlations
Creators: name: Veldhoen, Misha
Publisher: name: arXiv
Year: 2012
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: Particle ratios are important observables used to constrain models of particle production in heavy-ion collisions. In this work we report on a measurement of the p/pi ratio in the transverse momentum range 2.0 < p_{T,assoc} < 4.0 GeV/c, associated with a charged trigger particle of 5.0 < p_{T,trig} < 10.0 GeV/c, in 0-10% central Pb--Pb collisions at sqrt{s_{NN}}=2.76 TeV. The ratio is measured in the jet peak and in a region at large Delta eta separation from the peak (bulk region). The presented results are based on 14M minimum-bias Pb--Pb collisions, recorded by the ALICE detector. It is observed that the p/pi ratio in the bulk region is compatible with the p/pi ratio of an inclusive measurement, and is much larger than the p/pi ratio in the jet peak. The p/pi ratio in the jet peak is compatible with a PYTHIA reference, in which fragmentation in the vacuum is the dominant mechanism of particle production.
Estimands in Hematologic Oncology Trials
Creators: name: Sun, Steven
name: Weber, Hans-Jochen
name: Butler, Emily
name: Rufibach, Kaspar
name: Roychoudhury, Satrajit
Publisher: name: arXiv
Year: 2020
Subjects: subject: Other Quantitative Biology (q-bio.OT)
subject: Methodology (stat.ME)
subject: FOS: Biological sciences
subject: FOS: Computer and information sciences

description: The estimand framework included in the addendum to the ICH E9 guideline facilitates discussions to ensure alignment between the key question of interest, the analysis, and interpretation. Therapeutic knowledge and drug mechanism play a crucial role in determining the strategy and defining the estimand for clinical trial designs. Clinical trials in patients with hematological malignancies often present unique challenges for trial design due to complexity of treatment options and existence of potential curative but highly risky procedures, e.g. stem cell transplant or treatment sequence across different phases (induction, consolidation, maintenance). Here, we illustrate how to apply the estimand framework in hematological clinical trials and how the estimand framework can address potential difficulties in trial result interpretation. This paper is a result of a cross-industry collaboration to connect the International Conference on Harmonisation (ICH) E9 addendum concepts to applications. Three randomized phase 3 trials will be used to consider common challenges including intercurrent events in hematologic oncology trials to illustrate different scientific questions and the consequences of the estimand choice for trial design, data collection, analysis, and interpretation. Template language for describing estimand in both study protocols and statistical analysis plans is suggested for statisticians' reference.
description: 5 tables, 1 figure
Galaxy-cluster masses via 21st-century measurements of lensing of 21-cm fluctuations
Creators: name: Kovetz, Ely D.
name: Kamionkowski, Marc
Publisher: name: arXiv
Year: 2012
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We discuss the prospects to measure galaxy-cluster properties via weak lensing of 21-cm fluctuations from the dark ages and the epoch of reionization (EOR). We choose as a figure of merit the smallest cluster mass detectable through such measurements. We construct the minimum-variance quadratic estimator for the cluster mass based on lensing of 21-cm fluctuations at multiple redshifts. We discuss the tradeoff between frequency bandwidth, angular resolution, and number of redshift shells available for a fixed noise level for the radio detectors. Observations of lensing of the 21-cm background from the dark ages will be capable of detecting M>~10^12 Msun/h mass halos, but will require futuristic experiments to overcome the contaminating sources. Next-generation radio measurements of 21-cm fluctuations from the EOR will, however, have the sensitivity to detect galaxy clusters with halo masses M>~10^13 Msun/h, given enough observation time (for the relevant sky patch) and collecting area to maximize their resolution capabilities.
description: 10 pages, 6 figures; typos fixed, clarifications made, figure added; version as published in PRD
Radon backgrounds in the DEAP-1 liquid-argon-based Dark Matter detector
Creators: name: Amaudruz, P. -A.
name: Batygov, M.
name: Beltran, B.
name: Boudjemline, K.
name: Caldwell, M. G. Boulay B. Cai T.
name: Chen, M.
name: Chouinard, R.
name: Cleveland, B. T.
name: Contreras, D.
name: Dering, K.
name: Duncan, F.
name: Ford, R.
name: Giuliani, R. Gagnon F.
name: Golovko, M. Gold V. V.
name: Gorel, P.
name: Graham, K.
name: Grant, D. R.
name: Hakobyan, R.
name: Hallin, A. L.
name: Harvey, P.
name: Hearns, C.
name: Jillings, C. J.
name: Kuźniak, M.
name: Lawson, I.
name: Li, O.
name: Lidgard, J.
name: Liimatainen, P.
name: Lippincott, W. H.
name: Mathew, R.
name: McDonald, A. B.
name: McElroy, T.
name: McFarlane, K.
name: McKinsey, D.
name: Muir, A.
name: Nantais, C.
name: Nicolics, K.
name: Nikkel, J.
name: Noble, T.
name: O'Dwyer, E.
name: Olsen, K. S.
name: Ouellet, C.
name: Pasuthip, P.
name: Pollmann, T.
name: Rau, W.
name: Retiere, F.
name: Ronquest, M.
name: Skensved, P.
name: Sonley, T.
name: Tang, J.
name: Vázquez-Jáuregui, E.
name: Veloce, L.
name: Ward, M.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Nuclear Experiment (nucl-ex)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: The DEAP-1 \SI{7}{kg} single phase liquid argon scintillation detector was operated underground at SNOLAB in order to test the techniques and measure the backgrounds inherent to single phase detection, in support of the \mbox{DEAP-3600} Dark Matter detector. Backgrounds in DEAP are controlled through material selection, construction techniques, pulse shape discrimination and event reconstruction. This report details the analysis of background events observed in three iterations of the DEAP-1 detector, and the measures taken to reduce them. The $^{222}$Rn decay rate in the liquid argon was measured to be between 16 and \SI{26}{\micro\becquerel\per\kilogram}. We found that the background spectrum near the region of interest for Dark Matter detection in the DEAP-1 detector can be described considering events from three sources: radon daughters decaying on the surface of the active volume, the expected rate of electromagnetic events misidentified as nuclear recoils due to inefficiencies in the pulse shape discrimination, and leakage of events from outside the fiducial volume due to imperfect position reconstruction. These backgrounds statistically account for all observed events, and they will be strongly reduced in the DEAP-3600 detector due to its higher light yield and simpler geometry.
Non-decay of the energy for a system of semilinear wave equations
Creators: name: Nishii, Yoshinori
Publisher: name: arXiv
Year: 2020
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35L71, 35B40

description: We consider the global Cauchy problem for a two-component system of cubic semilinear wave equations in two space dimensions. We give a criterion for large time non-decay of the energy for small amplitude solutions in terms of the radiation fields associated with the initial data.
description: 10 pages
Light Dark Matter Candidate in B-L Gauged Radiative Inverse Seesaw
Creators: name: Kajiyama, Yuji
name: Okada, Hiroshi
name: Toma, Takashi
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study a radiative inverse seesaw model with local B-L symmetry, in which we extend the neutrino mass structure that is generated through a kind of inverse seesaw framework to the more generic one than our previous work. We focus on a real part of bosonic particle as a dark matter and investigate the features in O(1-80) GeV mass range, reported by the experiments such as CoGeNT and XENON (2012).
description: 10 pages, 1 table, 3 figures; version accepted for publication in European Physical Journal C
Record occurrence and record values in daily and monthly temperatures
Creators: name: Wergen, Gregor
name: Hense, Andreas
name: Krug, Joachim
Publisher: name: arXiv
Year: 2012
Subjects: subject: Atmospheric and Oceanic Physics (physics.ao-ph)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Physical sciences

description: We analyze the occurrence and the values of record-breaking temperatures in daily and monthly temperature observations. Our aim is to better understand and quantify the statistics of temperature records in the context of global warming. Similar to earlier work we employ a simple mathematical model of independent and identically distributed random variables with a linearly growing expectation value. This model proved to be useful in predicting the increase (decrease) in upper (lower) temperature records in a warming climate. Using both station and re-analysis data from Europe and the United States we further investigate the statistics of temperature records and the validity of this model. The most important new contribution in this article is an analysis of the statistics of record values for our simple model and European reanalysis data. We estimate how much the mean values and the distributions of record temperatures are affected by the large scale warming trend. In this context we consider both the values of records that occur at a certain time and the values of records that have a certain record number in the series of record events. We compare the observational data both to simple analytical computations and numerical simulations. We find that it is more difficult to describe the values of record breaking temperatures within the framework of our linear drift model. Observations from the summer months fit well into the model with Gaussian random variables under the observed linear warming, in the sense that record breaking temperatures are more extreme in the summer. In winter however a significant asymmetry of the daily temperature distribution hides the effect of the slow warming trends. Therefore very extreme cold records are still possible in winter. This effect is even more pronounced if one considers only data from subpolar regions.
description: 16 pages, 20 figures, revised version, published in Climate Dynamics
On a Couple of Unresolved Group Testing Conjectures
Creators: name: Čižikovienė, Ugnė
name: Skorniakov, Viktor
Publisher: name: arXiv
Year: 2021
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics

description: In the recent review published in 2019, Malinovsky and Albert conjectured analytical formulae of the optimal sample sizes for the modified Dorfman and Sterret group testing schemes and verified the validity of the formulae numerically within a broad range. However, the authors pointed out that they were unable to give a rigorous proof of the stated conjectures. In this note, we affirm and refine their hypotheses analitically thereby filling in the present gap.
Study design in causal models
Creators: name: Karvanen, Juha
Publisher: name: arXiv
Year: 2012
Subjects: subject: Methodology (stat.ME)
subject: Applications (stat.AP)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences
subject: G.3; G.2.2
subject: 62A01, 62-09, 62F99, 62D05, 62P10, 62K99, 68T30

description: The causal assumptions, the study design and the data are the elements required for scientific inference in empirical research. The research is adequately communicated only if all of these elements and their relations are described precisely. Causal models with design describe the study design and the missing data mechanism together with the causal structure and allow the direct application of causal calculus in the estimation of the causal effects. The flow of the study is visualized by ordering the nodes of the causal diagram in two dimensions by their causal order and the time of the observation. Conclusions whether a causal or observational relationship can be estimated from the collected incomplete data can be made directly from the graph. Causal models with design offer a systematic and unifying view scientific inference and increase the clarity and speed of communication. Examples on the causal models for a case-control study, a nested case-control study, a clinical trial and a two-stage case-cohort study are presented.
description: The example on the MORGAM Project extended is in this version
A Taxonomy of Assets for the Development of Software-Intensive Products and Services
Creators: name: Zabardast, Ehsan
name: Gonzalez-Huerta, Javier
name: Gorschek, Tony
name: Šmite, Darja
name: Alégroth, Emil
name: Fagerholm, Fabian
Publisher: name: arXiv
Year: 2021
Subjects: subject: Software Engineering (cs.SE)
subject: FOS: Computer and information sciences

description: Context: Developing software-intensive products or services usually involves a plethora of software artefacts. Assets are artefacts intended to be used more than once and have value for organisations; examples include test cases, code, requirements, and documentation. During the development process, assets might degrade, affecting the effectiveness and efficiency of the development process. Therefore, assets are an investment that requires continuous management. Identifying assets is the first step for their effective management. However, there is a lack of awareness of what assets and types of assets are common in software-developing organisations. Most types of assets are understudied, and their state of quality and how they degrade over time have not been well-understood. Method: We perform a systematic literature review and a field study at five companies to study and identify assets to fill the gap in research. The results were analysed qualitatively and summarised in a taxonomy. Results: We create the first comprehensive, structured, yet extendable taxonomy of assets, containing 57 types of assets. Conclusions: The taxonomy serves as a foundation for identifying assets that are relevant for an organisation and enables the study of asset management and asset degradation concepts.
description: Submitted to the Journal of Systems and Software (JSS)
Atomic nonclassicality quasiprobabilities
Creators: name: Kiesel, T.
name: Vogel, W.
name: Christensen, S. L.
name: Béguin, J. -B.
name: Appel, J.
name: Polzik, E. S.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Although nonclassical quantum states are important both conceptually and as a resource for quantum technology, it is often difficult to test whether a given quantum system displays nonclassicality. A simple method to certify nonclassicality is introduced, based on easily accessible collective atomic quadrature measurements, without the need of full state tomography. The statistics is analyzed beyond the ground-state noise level, by direct sampling of a regularized atomic quadrature quasiprobability. Nonclassicality of a squeezed ensemble of 2x10^5 Cesium atoms is demonstrated, with a significance of up to 23 standard deviations.
description: 5 pages, 2 figures