cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Strong convergence rates of an explicit scheme for stochastic Cahn--Hilliard equation with additive noise
Creators: name: Cai, Meng
name: Qi, Ruisheng
name: Wang, Xiaojie
Publisher: name: arXiv
Year: 2022
Subjects: subject: Numerical Analysis (math.NA)
subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 65M75, 60H15, 60H35

description: In this paper, we propose and analyze an explicit time-stepping scheme for a spatial discretization of stochastic Cahn--Hilliard equation with additive noise. The fully discrete approximation combines a spectral Galerkin method in space with a tamed exponential Euler method in time. In contrast to implicit schemes in the literature, the explicit scheme here is easily implementable and produces significant improvement in the computational efficiency. It is shown that the fully discrete approximation converges strongly to the exact solution, with strong convergence rates identified. Different from the tamed time-stepping schemes for stochastic Allen--Cahn equations, essential difficulties arise in the analysis due to the presence of the unbounded linear operator in front of the nonlinearity. To overcome them, new and non-trivial arguments are developed in the present work. To the best of our knowledge, it is the first result concerning an explicit scheme for the stochastic Cahn--Hilliard equation. Numerical experiments are finally performed to confirm the theoretical results.
description: 34 pages, 5 figures
Reference Energies for Cyclobutadiene: Automerization and Excited States
Creators: name: Monino, Enzo
name: Boggio-Pasqua, Martial
name: Scemama, Anthony
name: Jacquemin, Denis
name: Loos, Pierre-François
Publisher: name: arXiv
Year: 2022
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: Cyclobutadiene is a well-known playground for theoretical chemists and is particularly suitable to test ground- and excited-state methods. Indeed, due to its high spatial symmetry, especially at the $D_{4h}$ square geometry but also in the $D_{2h}$ rectangular arrangement, the ground and excited states of cyclobutadiene exhibit multi-configurational characters and single-reference methods, such as adiabatic time-dependent density-functional theory (TD-DFT) or equation-of-motion coupled cluster (EOM-CC), are notoriously known to struggle in such situations. In this work, using a large panel of methods and basis sets, we provide an extensive computational study of the automerization barrier (defined as the difference between the square and rectangular ground-state energies) and the vertical excitation energies at $D_{2h}$ and $D_{4h}$ equilibrium structures. In particular, selected configuration interaction (SCI), multi-reference perturbation theory (CASSCF, CASPT2, and NEVPT2), and coupled-cluster (CCSD, CC3, CCSDT, CC4, and CCSDTQ) calculations are performed. The spin-flip formalism, which is known to provide a qualitatively correct description of these diradical states, is also tested within TD-DFT (combined with numerous exchange-correlation functionals) and the algebraic diagrammatic construction [ADC(2)-s, ADC(2)-x, and ADC(3)] schemes. A theoretical best estimate is defined for the automerization barrier and for each vertical transition energy.
description: 15 pages, 4 figures (supporting information available)
Scheduling Coflows for Minimizing the Total Weighted Completion Time in Heterogeneous Parallel Networks
Creators: name: Chen, Chi-Yeh
Publisher: name: arXiv
Year: 2022
Subjects: subject: Data Structures and Algorithms (cs.DS)
subject: FOS: Computer and information sciences

description: Coflow is a network abstraction used to represent communication patterns in data centers. The coflow scheduling problem in large data centers is one of the most important $NP$-hard problems. Many previous studies on coflow scheduling mainly focus on the single-core model. However, with the growth of data centers, this single-core model is no longer sufficient. This paper considers the coflow scheduling problem in heterogeneous parallel networks. The heterogeneous parallel network is an architecture based on multiple network cores running in parallel. In this paper, two polynomial-time approximation algorithms are developed for scheduling divisible and indivisible coflows in heterogeneous parallel networks, respectively. Considering the divisible coflow scheduling problem, the proposed algorithm achieve an approximation ratio of $O(\log m/ \log \log m)$ with arbitrary release times, where $m$ is the number of network cores. On the other hand, when coflow is indivisible, the proposed algorithm achieve an approximation ratio of $O\left(m\left(\log m/ \log \log m\right)^2\right)$ with arbitrary release times.
description: arXiv admin note: text overlap with arXiv:2204.02651
Da desfuturização da GRH numa organização temporária
Creators: name: Coelho, João Vasco
Publisher: name: Revista de Ciências Empresariais e Jurídicas / Review of Business and Legal Sciences
Year: 2017

description: No contexto nacional, a referência a uma organização start-up, tem definido, no plano dos discursos político e mediático, uma amenidade, uma platitude, correlativa da apologia dos seus méritos como factos consumados, anódinos, salvíficos. Neste quadro, é reduzida a visibilidade de perspectivas que procurem interrogar este fenómeno, em si mesmo relevante, para uma putativa recomposição das práticas que enformam a actividade económica nacional . Apresentando como suporte empírico um conjunto de observações registadas em diário de campo constituído no decurso de uma pesquisa longitudinal realizada entre Novembro de 2014 e Novembro 2015, numa das organizações start-up portuguesas que maior crescimento (e visibilidade) tem conhecido nos últimos três anos, o presente artigo procura explorar a praxis da gestão de RH (GRH) observável no contexto de uma organização start-up. Regista-se, em termos empíricos, uma praxis de GRH tributária de uma lógica e uma cultura de gestão ancorada na experimentação e na descontinuidade, que são apresentadas, em termos discursivos, como necessidades estratégicas da organização . Num quadro de ação pontuado pela incerteza, a promoção deliberada de rutura(s), de descontinuidade (nas práticas, nas equipas, nos objectivos), procura afirmar uma aparência de desenvolvimento distintivo da organização start-up, o acesso a um estádio de maturidade organizacional qualitativamente diferenciada . Trata-se de uma GRH desfuturizada, cujo foco é colocado, no essencial, no presente imediato. Sugerem-se duas implicações desta orientação normativa: a persistência de um sentido geral de incerteza, volatilidade e impermanência; a tendência de desfuturização de práticas de gestão e de experiências individuais de trabalho .
description: Revista de Ciências Empresariais e Jurídicas / Review of Business and Legal Sciences, No. 29 (2017): Revista de Ciências Empresariais e Jurídicas / Review of Business and Legal Sciences
Electrical Current from Quantum Vacuum Fluctuations in Nano-engines
Creators: name: Henriet, Loïc
name: Jordan, Andrew N.
name: Hur, Karyn Le
Publisher: name: arXiv
Year: 2015
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We theoretically investigate a quantum dot coupled to fermionic (electronic) leads and show how zero-point quantum fluctuations stemming from bosonic environments permit the rectification of the current. The bosonic baths are either external impedances modeled as tunable transmission lines or LC resonators (single-mode cavities). Voltage fluctuations stemming from the external impedances at zero temperature are described through harmonic oscillators (photon-like excitations) then producing the quantum vacuum fluctuations. The differing sizes of the zero-point fluctuations of the quantum vacuum break the spatial symmetry of the system if the quantum dot is coupled to two reservoirs or two junctions with different bosonic environments. We consider current rectification and power production when the system is operated as a heat engine in both non-resonant and resonant sequential tunneling cases.
description: 9 pages
Conceptual framework
Creators: name: Carvalho, Francisco Edinaldo Lira De
Publisher: name: Revista de Ciências Empresariais e Jurídicas / Review of Business and Legal Sciences
Year: 2017

description: Relacionando historicamente a importância dos conhecimentos com a busca do excelente desempenho organizacional, percebe-se que as organizações sempre foram dependentes da adoção de práticas e de processos para identificar, gerir e manter os seus conhecimentos. Com este contexto, esta comunicação objetiva refletir sobre a evolução da gestão, da interpretação e da perceção do conhecimento por meio dos chamados conceptual framework, utilizados para a interpretação e gestão do conhecimento . Quanto utilização, os conceptuais framework que hoje são utilizados na gestão do conhecimento podem ser considerados uma intersecção de duas áreas, nomeadamente as ciências de gestão com as ciências de tecnologia de informação e comunicação. São estes diagramas de construção teórica, mas de utilização prática, que são desenvolvidos para representar e modelar as informações de um fenómeno no âmbito do conhecimento organizacional (Ichijo and Nonaka, 2007), sendo aplicados nos processos empresariais ou nas investigações científicas em gestão. Com o exposto, esta comunicação objetiva apresentar os seguintes objetivos: 1 – Refletir sobre a evolução da gestão, da interpretação e da perceção do conhecimento por meio dos chamados conceptual framework, utilizados para a interpretação e gestão do conhecimento; 2 – Evidenciar a importância estratégica da gestão do conhecimento para as organizações, por meio da plena perceção de suas ferramentas e particularidades demonstradas em casos praticas;3 – Demonstrar a evolução dos conceitos de conceptual framework em relação a gestão do conhecimento, e ; 4 – Apresentar um quadro teórico da aplicação de conceptual framework na área consultiva empresarial e em investigação científica de gestão. Para atingir estes objetivos, esta comunicação metodologicamente buscou identificar estes chamados modelos conceptual em 12 casos práticos de organizações empresariais já registados pela literatura (Holsapple and Joshi, 2008)e em 05 casos relacionados com a utilização de modelos conceptual na investigação científica de fenómenos de gestão, com os modelos conceptual de moderadores, antecedentes e out comes (Gibson and Birkinshaw, 2004, Raisch and Birkinshaw, 2008).
description: Revista de Ciências Empresariais e Jurídicas / Review of Business and Legal Sciences, No. 29 (2017): Revista de Ciências Empresariais e Jurídicas / Review of Business and Legal Sciences
A descent principle for compactly supported extensions of functors
Creators: name: Kuijper, Josefien
Publisher: name: arXiv
Year: 2022
Subjects: subject: Algebraic Geometry (math.AG)
subject: Algebraic Topology (math.AT)
subject: K-Theory and Homology (math.KT)
subject: FOS: Mathematics
subject: 14F99 (primary), 18F10, 55U99, 14F42 (secondary)

description: A characteristic property of cohomology with compact support is the long exact sequence that connects the compactly supported cohomology groups of a space, an open subspace and its complement. Given an arbitrary cohomology theory of algebraic varieties, one can ask whether a compactly supported version exists, satisfying such a long exact sequence. This is the case whenever the cohomology theory satisfies descent for abstract blowups (also known as proper cdh descent). We make this precise by proving an equivalence between certain categories of hypersheaves. We show how several classical and non-trivial results, such as the existence of a unique weight filtration on cohomology with compact support, can be derived from this theorem.
description: 35 pages. Added section 8D, numbering made consistent with journal version. To appear in Annals of K-theory
The Role of Nix-Mediated Mitophagy in Muscle Stem Cell Fate Decision and Muscle Regeneration
Creators: name: Racine, Jérémy
Publisher: name: Université d'Ottawa / University of Ottawa
Year: 2024
Subjects: Muscle stem cells
Mitophagy
BNIP3L/NIX
Muscle regeneration
Myogenesis

description: Skeletal muscle is among the tissues displaying the greatest plasticity, attributable to a population of muscle stem cells (MuSCs). At basal conditions, MuSCs are in a standby state called quiescence. Once activated, they can either self-renew or commit toward myogenesis. This balance is required to mount an adequate repair response while maintaining long-term regenerative capacity. In this regard, mitochondria have emerged as important hubs for integrating signals and regulating stem cell behaviour. Mitophagy regulates mitochondrial properties through the autophagic degradation of organelles, suggesting an importance in MuSCs fate. Transcriptomic analysis of quiescent and activated MuSCs highlighted the Nix mitophagy pathway as a key player in quiescence maintenance. Nix is an important ubiquitin-independent mitophagy pathway in stem cell regulation. To test the role of Nix in MuSCs fate decision and muscle regeneration, we developed a conditional knock-out mouse model of Nix specific to MuSCs. First, we reveal that deleting Nix in vivo caused a significant decrease in mitophagy levels in quiescent and early-activated MuSCs. Next, using in vitro studies of culturing single myofibers, we show that Nix deletion alters MuSC fate decisions by causing premature and increased activation and commitment while depleting the MuSC pool. In vivo injury experiments further validate these observations, showing decreased self-renewal capacity post-muscle repair. We propose that dysregulation of Nix-mediated mitophagy disrupts MuSC fate and lineage progression, ultimately leading to muscle impairment. This study sheds light on the intricate interplay between mitophagy and MuSC behaviour, offering insights into potential therapeutic strategies for muscle regeneration.
The Polarity of Arab Canadians' Political Affiliations
Creators: name: Abou-El-Kheir, Engi
Publisher: name: Université d'Ottawa / University of Ottawa
Year: 2024
Subjects: Arab Canadians
Arab Canadian values
Arab Canadian political ideology
Arab Canadian partisanship
Canadian immigrant partisanship
Minority voting
Visible minority voting

description: This research looks at the political ideology and political affiliation of Arab Canadians. This specific population is especially interesting politically due to the intersections of different ethnicities, cultures, and religions. This fills the gap of quantitative research on the political choices of Arab-origin people in Canada, of which there is little to none. It also adds on to the literature on the voting patterns and partisanship of the larger population of visible minorities and/or immigrant origin Canadians, which previous research has not found statistically significant reasons of strong and consistent Liberal Party support by. This also provides an addition to the barren field of qualitative research on Arab Canadian political opinions. In order to analyze Arab Canadian vote choice, I built three primary datasets (Arab Canadian, immigrant Canadian, born Canadian) from the Canadian Election Study (CES) results from 2000 to 2021, and analyzed descriptive statistics and ran multinomial logistic regressions based on respondents' vote choice for patterns and significance. I hypothesize and confirm that Arab Canadians vote more consistently Liberal than born Canadians, despite also being more religious than the general population. The regressions show that the Canadian and immigrant populations are much more alike than Arab Canadians. I carry out twenty interviews with Arab Canadians to confirm and deepen the understanding of the quantitative results. The participants share that the strongest reason for their Liberal vote is Liberal rhetoric and values focused on multiculturalism and acceptance of Arabs/Muslims/immigrants, as well as their progressive values.
A relevância da eficácia individual na dinâmica organizacional – um estudo quantitativo
Creators: name: Pereira, Manuel Joaquim De Sousa
Publisher: name: Revista de Ciências Empresariais e Jurídicas / Review of Business and Legal Sciences
Year: 2017

description: A escolha deste tema surgiu da necessidade de compreender a gestão da comunicação nas pequenas e médias empresas ao nível das dinâmicas pessoal e empresarial, do desempenho empresarial, da reputação pessoal, da proatividade e dinâmica empresarial, da organização aprendente e da motivação e sucesso empresarial . . Abordamos, desta forma, a estratégia e a mudança organizacional, a motivação e as necessidades individuais e empresariais no que diz respeito ao desenvolvimento das capacidades, do desempenho dos colaboradores e da sua motivação e melhoria contínua do sucesso empresarial . A amostra é constituída por 388 pequenas e médias empresas em Portugal continental . Assim, no pressuposto de termos uma amostra probabilística, e considerando um intervalo de confiança de duas vezes o desvio padrão, ou seja de 95,4%, temos a margem máxima de erro estatístico (P= 50%) de +/- 4,95 p.p.). Procuramos estudar também a atitude dos gestores face à orientação para o mercado, os comportamentos da organização, as atitudes e retenção do pessoal, a satisfação dos clientes, satisfação dos empregados, comprometimento, envolvimento, reputação e performance empresarial, a recomendação, os indicadores empresariais e grau de satisfação em trabalhar nas organizações. Verificamos assim que, os aspetos relevantes para a eficiência do desempenho dos colaboradores residem na atitude positiva, na autoanálise, na automotivação, na definição de objetivos, aliados à capacidade de gerar ação compreendendo os demais para ser compreendido na organização onde está inserido .
description: Revista de Ciências Empresariais e Jurídicas / Review of Business and Legal Sciences, No. 29 (2017): Revista de Ciências Empresariais e Jurídicas / Review of Business and Legal Sciences
Assessing Heterogeneity in Students’ Visual Judgment: Model-Based Partitioning of Image Rankings
Creators: name: Tallon, Miles
name: Greenlee, Mark W.
name: Wagner, Ernst
name: Rakoczy, Katrin
name: Wiedermann, Wolfgang
name: Frick, Ulrich
Publisher: name: Universität Regensburg
Year: 2022
Subjects: subject: PAIRED-COMPARISON DATA; AESTHETIC JUDGMENT; ABSTRACTION; PERCEPTION; visual abstraction; assessment; Bradley-Terry model; model-based partitioning; ranking; art education; visual literacy
subject: 150 Psychologie

description: Differences in the ability of students to judge images can be assessed by analyzing the individual preference order (ranking) of images. To gain insights into potential heterogeneity in judgement of visual abstraction among students, we combine Bradley-Terry preference modeling and model-based recursive partitioning. In an experiment a sample of 1,020 high-school students ranked five sets of images, three of which with respect to their level of visual abstraction. Additionally, 24 art experts and 25 novices were given the same task, while their eye movements were recorded. Results show that time spent on the task, the students' age, and self-reported interest in visual puzzles had significant influence on rankings. Fixation time of experts and novices revealed that both groups paid more attention to ambiguous images. The presented approach makes the underlying latent scale of visual judgments quantifiable.
High-pressure powder x-ray diffraction study of EuVO4
Creators: name: Garg, Alka B.
name: Errandonea, D.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: The high-pressure structural behavior of europium orthovanadate has been studied using in-situ, synchrotron based, high-pressure x-ray powder diffraction technique. Angle-dispersive x-ray diffraction measurements were carried out at room temperature up to 34.7 GPa using a diamond-anvil cell, extending the pressure range reported in previous experiments. We confirmed the occurrence of zircon-scheelite phase transition at 6.8 GPa and the coexistence of low- and high-pressure phases up to 10.1 GPa. In addition, clear evidence of a scheelite-fregusonite transition is found at 23.4 GPa. The fergusonite structure remains stable up to 34.7 GPa, the highest pressure reached in the present measurements. A partial decomposition of EuVO4 was also observed from 8.1 to 12.8 GPa, however, this fact did not preclude the identification of the different crystal structures of EuVO4. The crystal structures of the different phases have been Rietveld refined and their equations of state (EOS) have been determined. The results are compared with the previous experimental data and theoretical calculations.
description: 28 pages, 2 Tables, 6 Figures, to appear in Journal of Solid State Chemistry. arXiv admin note: text overlap with arXiv:1405.1889
On the separation of correlation-assisted sum capacities of multiple access channels
Creators: name: Seshadri, Akshay
name: Leditzky, Felix
name: Siddhu, Vikesh
name: Smith, Graeme
Publisher: name: arXiv
Year: 2022
Subjects: subject: Information Theory (cs.IT)
subject: Quantum Physics (quant-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: The capacity of a channel characterizes the maximum rate at which information can be transmitted through the channel asymptotically faithfully. For a channel with multiple senders and a single receiver, computing its sum capacity is possible in theory, but challenging in practice because of the nonconvex optimization involved. To address this challenge, we investigate three topics in our study. In the first part, we study the sum capacity of a family of multiple access channels (MACs) obtained from nonlocal games. For any MAC in this family, we obtain an upper bound on the sum rate that depends only on the properties of the game when allowing assistance from an arbitrary set of correlations between the senders. This approach can be used to prove separations between sum capacities when the senders are allowed to share different sets of correlations, such as classical, quantum or no-signalling correlations. We also construct a specific nonlocal game to show that the approach of bounding the sum capacity by relaxing the nonconvex optimization can give arbitrarily loose bounds. Owing to this result, in the second part, we study algorithms for non-convex optimization of a class of functions we call Lipschitz-like functions. This class includes entropic quantities, and hence these results may be of independent interest in information theory. Subsequently, in the third part, we show that one can use these techniques to compute the sum capacity of an arbitrary two-sender MACs to a fixed additive precision in quasi-polynomial time. We showcase our method by efficiently computing the sum capacity of a family of two-sender MACs for which one of the input alphabets has size two. Furthermore, we demonstrate with an example that our algorithm may compute the sum capacity to a higher precision than using the convex relaxation.
description: v3: 70 pages, 3 figures; to appear in IEEE Transactions on Information Theory
Cool core cycles: Cold gas and AGN jet feedback in cluster cores
Creators: name: Prasad, Deovrat
name: Sharma, Prateek
name: Babul, Arif
Publisher: name: arXiv
Year: 2015
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Using high-resolution 3-D and 2-D (axisymmetric) hydrodynamic simulations in spherical geometry, we study the evolution of cool cluster cores heated by feedback-driven bipolar active galactic nuclei (AGN) jets. Condensation of cold gas, and the consequent enhanced accretion, is required for AGN feedback to balance radiative cooling with reasonable efficiencies, and to match the observed cool core properties. A feedback efficiency (mechanical luminosity $\approx ε\dot{M}_{\rm acc} c^2$; where $\dot{M}_{\rm acc}$ is the mass accretion rate at 1 kpc) as small as $5 \times 10^{-5}$ is sufficient to reduce the cooling/accretion rate by $\sim 10$ compared to a pure cooling flow. This value is smaller compared to the ones considered earlier, and is consistent with the jet efficiency and the fact that only a small fraction of gas at 1 kpc is accreted on to the supermassive black hole (SMBH). We find hysteresis cycles in all our simulations with cold mode feedback: {\em condensation} of cold gas when the ratio of the cooling-time to the free-fall time ($t_{\rm cool}/t_{\rm ff}$) is $\lesssim 10$ leads to a sudden enhancement in the accretion rate; a large accretion rate causes strong jets and {\em overheating} of the hot ICM such that $t_{\rm cool}/t_{\rm ff} > 10$; further condensation of cold gas is suppressed and the accretion rate falls, leading to slow cooling of the core and condensation of cold gas, restarting the cycle. Therefore, there is a spread in core properties, such as the jet power, accretion rate, for the same value of core entropy or $t_{\rm cool}/t_{\rm ff}$. A fewer number of cycles are observed for higher efficiencies and for lower mass halos because the core is overheated to a longer cooling time. The 3-D simulations show the formation of a few-kpc scale, rotationally-supported, massive ($\sim 10^{11} M_\odot$) cold gas torus. (abstract abridged)
description: 22 pages, 15 figures; ApJ accepted version (figures downgraded to smaller size, as required for arxiv submission)
Servant leadership through arts – a state of the art
Creators: name: Barroca, Ana
name: Neto, Catarina
name: Silveira, Ana
Publisher: name: Review of Business and Legal Sciences / Revista de Ciências Empresariais e Jurídicas
Year: 2017

description: The future leaders are growing in the digital era and through a profound crisis. These future leaders demand for purpose, meaning and connection and they will be working in organisations also shaped by the globalisation of knowledge, markets and customers and the information and communication technology. The Artful Leadership project aims at developing the new generation of servant leaders through arts. The Erasmus + Programme co-funded the Artful Leadership consortium to research and develop new learning resources that can empower a leadership shift. The research phase allowed the project consortium to explore the main drivers changing society, business and learning and to ask which model of leadership will be more suitable to live and be successful today and in the future; as well as, which tools could be more effective to reach and engage future leaders through a learning journey and disrupting with the onetime training event. The approach to servant leadership was subsequent and allowed to understand the background, its main characteristics and what the impact when experienced in different organisations is. Finally, arts based learning concept, characteristics and good practices were explored focusing on the impact it brings when applied into management and leadership educational programs.
description: Review of Business and Legal Sciences / Revista de Ciências Empresariais e Jurídicas, No. 29 (2017): Revista de Ciências Empresariais e Jurídicas / Review of Business and Legal Sciences
Order/disorder dynamics in a dodecanethiol-capped gold nanoparticles supracrystal by small-angle ultrafast electron diffraction
Creators: name: Mancini, Giulia Fulvia
name: Latychevskaia, Tatiana
name: Pennacchio, Francesco
name: Reguera, Javier
name: Stellacci, Francesco
name: Carbone, Fabrizio
Publisher: name: arXiv
Year: 2015
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: In metal nanoparticles (NPs) supracrystals, the metallic core provides some key properties, e.g. magnetization, plasmonic response or conductivity, with the ligand molecules giving rise to others like solubility, assembly or interaction with biomolecules. The formation of these supracrystals depends on a complex interplay between many forces, some stemming from the core, some from the ligands. At present, there is no known approach to characterize the local order of ligand molecules or their dynamics with atomic spatial resolution. Here, we develop a methodology based on small-angle ultrafast electron diffraction combined with angular cross-correlation analysis to characterize a two-dimensional supracrystal of dodecanethiol-coated gold NPs. We retrieve the static arrangement of the ligands, showing that at equilibrium they order in a preferential orientation on the NPs surface and throughout the two-dimensional supracrystal. Upon light excitation, positional disorder is induced in the supracrystal, while its overall homogeneity is surprisingly found to transiently increase. This suggests that transient annealing of the supracrystal takes place within few picoseconds (ps). This methodology will enable the systematic investigation of the dynamical structural properties of nano-assembled materials containing light elements, relevant for biological applications.
Spectral reciprocity via integral representations
Creators: name: Nunes, Ramon M.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics

description: We prove a spectral reciprocity formula for automorphic forms on $\mathrm{GL}(2)$ over a number field that is remininscent of the one found by Blomer and Khan. Our approach uses period representations of $L$-functions and the language of automorphic representations.
description: Many improvements throughout the text. Including the inclusion of a previously neglected main term
Estimation of radiation scalar using deep learning for improved gross primary productivity estimation based on a light-use efficiency model
Creators: name: Sun, Yukang
name: Yuan, Dekun
name: Zheng, Xin
name: Yang, Shanshan
name: Zhang, Sha
name: Zhang, Jiahua
name: Bai, Yun
Publisher: name: Taylor & Francis
Year: 2024
Subjects: subject: Biotechnology
subject: Ecology
subject: FOS: Biological sciences
subject: Biological Sciences not elsewhere classified
subject: Information Systems not elsewhere classified

description: Accurately quantifying terrestrial gross primary productivity (GPP) can provide insights into the dynamics of global ecosystems. Light Use Efficiency (LUE) models with simple and effective structures have been widely used to estimate GPP. However, GPP estimation using LUE models was biased due to inaccurately representing the nonlinear effect of solar radiation on photosynthesis. To address this issue, we developed a hybrid LUE model, termed LUE-MLP, which integrates a multilayer perceptron (MLP) neural network simulating the relationship between GPP and solar radiation with a big-leaf LUE model. LUE-MLP was optimized and tested for GPP simulation on data from 166 flux sites from the FLUXNET2015 dataset, which covers 10 biome types. Results show that LUE-MLP exhibited a reliable performance (R2 = 0.76 and RMSE = 4.17 μmol m−2 s−1) in estimating (half-)hourly GPP on test data. Compared to the original big-leaf and two-leaf LUE models, LUE-MLP's R² (RMSE) for (half-)hourly GPP simulation across biomes rose (fell) by – 0.01-0.13 (−7.6%−16.8%) and 0.01-0.15 (0.39%−29.1%), respectively. Additionally, LUE-MLP well captured the seasonal variations in tower-based GPP. The proposed model can improve GPP estimation on a global scale, enhancing our understanding of global ecosystem dynamics.
Ficha técnica
Creators: name: OJS, Admin
Publisher: name: Revista de Ciências Empresariais e Jurídicas / Review of Business and Legal Sciences
Year: 2018

description: Revista de Ciências Empresariais e Jurídicas / Review of Business and Legal Sciences, No. 29 (2017): Revista de Ciências Empresariais e Jurídicas / Review of Business and Legal Sciences
SNN2ANN: A Fast and Memory-Efficient Training Framework for Spiking Neural Networks
Creators: name: Tang, Jianxiong
name: Lai, Jianhuang
name: Xie, Xiaohua
name: Yang, Lingxiao
name: Zheng, Wei-Shi
Publisher: name: arXiv
Year: 2022
Subjects: subject: Neural and Evolutionary Computing (cs.NE)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Spiking neural networks are efficient computation models for low-power environments. Spike-based BP algorithms and ANN-to-SNN (ANN2SNN) conversions are successful techniques for SNN training. Nevertheless, the spike-base BP training is slow and requires large memory costs. Though ANN2NN provides a low-cost way to train SNNs, it requires many inference steps to mimic the well-trained ANN for good performance. In this paper, we propose a SNN-to-ANN (SNN2ANN) framework to train the SNN in a fast and memory-efficient way. The SNN2ANN consists of 2 components: a) a weight sharing architecture between ANN and SNN and b) spiking mapping units. Firstly, the architecture trains the weight-sharing parameters on the ANN branch, resulting in fast training and low memory costs for SNN. Secondly, the spiking mapping units ensure that the activation values of the ANN are the spiking features. As a result, the classification error of the SNN can be optimized by training the ANN branch. Besides, we design an adaptive threshold adjustment (ATA) algorithm to address the noisy spike problem. Experiment results show that our SNN2ANN-based models perform well on the benchmark datasets (CIFAR10, CIFAR100, and Tiny-ImageNet). Moreover, the SNN2ANN can achieve comparable accuracy under 0.625x time steps, 0.377x training time, 0.27x GPU memory costs, and 0.33x spike activities of the Spike-based BP model.
Retrato da mudança na transição dos CNO para os CQEP – desafios da descontinuidade
Creators: name: Silva, Géraldine Pereira Da
name: Ferreira, Maria Elisete Martins
Publisher: name: Revista de Ciências Empresariais e Jurídicas / Review of Business and Legal Sciences
Year: 2017

description: No âmbito da educação de adultos, ocorreram mudanças significativas na transição dos Centros Novas Oportunidades (CNO) para os Centros para a Qualificação e o Ensino Profissional (CQEP). Se a Iniciativa Novas Oportunidades consistiu numa aposta da Educação de Adultos em Portugal, a transição para os CQEP desencadeou uma mudança no paradigma . No sentido de retratar a perceção que as equipas dos CNO tiveram no processo de transição e medidas organizacionais que ocorrem entre os CNO e os CQEP, foi aplicado um questionário destinado aos ex-trabalhadores dos CNO . Os resultados obtidos permitiram concluir que apenas 17% dos inquiridos foi admitido num CQEP; os inquiridos detentores de um mestrado foram estatisticamente os que menos foram integrados num CQEP e os que menos acreditaram poderem vir a integrar um CQEP, quando comparados com inquiridos detentores de um grau de habilitações inferior; Os ex-trabalhadores dos CNO foram integrados em maior número na região de Lisboa e Vale do Tejo, e em menor número na região do Alentejo e Algarve. No que concernem as práticas organizacionais no processo de transição entre os CNO e os CQEP, os inquiridos afirmaram maioritariamente ter existido uma ausência de ações de comunicação a explicar o encerramento dos CNO junto dos trabalhadores; a ausência de pedidos de colaboração no processo de transição destas duas estruturas; a ausência de informação sobre uma possível recondução para um CQEP e o não cumprimento dos prazos estipulados pela ANQEP para a criação dos CQEP . Por último, constata-se que independentemente da integração ou não dos ex-trabalhadores dos CNO num CQEP, a maioria dos inquiridos não concordou com a forma como o processo de transição entre estas duas estruturas ocorreu .
description: Revista de Ciências Empresariais e Jurídicas / Review of Business and Legal Sciences, No. 29 (2017): Revista de Ciências Empresariais e Jurídicas / Review of Business and Legal Sciences
Detecting 40K geoneutrinos with LiquidO
Creators: name: Andrea, Serafini
name: Marica, Baldoncini
name: Anatael, Cabrera
name: Mark, Chen
name: Fabio, Mantovani
name: Virginia, Strati
name: Stefan, Wagner
name: LiquidO Consortium
Publisher: name: Zenodo
Year: 2019
Subjects: neutrino
geoneutrino
LiquidO
Potassium

description: From 25% to 70% of Earth’s internal heat budget is deemed to be generated by the radioactive decay of the so-called heat-producing elements (i.e. U, Th and K). Potassium, the only semi-volatile element among them, seems to show from 10% to 30% of its expected chondritic abundance, making thus uncertain any heat balance estimation. Two theories stand on the possible fate of “missing K”: i) segregation of potassium into the core or ii) loss to space during planetary accretion. No experimental corroboration allows confirmation of these hypotheses yet. As a consequence, our knowledge of Earth’s internal heat budget and its thermal evolution has to rely on compositional models. Direct geoneutrino detection, however, permits to constrain, at least in part, Earth’s radiogenic heat production and its Urey ratio. Unfortunately, present state-of-the-art detection techniques based on Inverse Beta Decay (IBD) on free protons only permit the detection of geoneutrinos having energy above 1.8 MeV, leaving 40K-geoneutrinos (whose endpoint is at 1.3 MeV) impossible to detect. Detection via NC interactions such as elastic scattering has been proposed; however, solar and radioactivity backgrounds remain challenges limiting its feasibility.
 The novel LiquidO detection technique (Cabrera A. et al. - Neutrino Physics with an Opaque Detector - arXiv:1908.02859 - 2019) allows enabling for the first time the observation of 40K-geoneutrinos. LiquidO opaque detection medium allows for unprecedented particle identification and large loading capabilities for neutrino detection. A clear identification of single positrons event topology is possible upon CC interactions of geoneutrinos. This feature opens the door for the exploitation of loaded isotopes leading to new IBD interactions, making it thus possible to lower the minimum detectable antineutrino energy. A review of possible target candidates able to detect 40K-geoneutrinos will be presented here, together with their IBD cross-section and the corresponding expected signal for four different potential experimental sites. A few novels of possible isotope targets are presented here for the first time. The detection significance and the statistical uncertainty will then be discussed together with a possible methodology for the 40K-geoneutrino signal extraction.
description: {"references": ["LiquidO Web: https://liquido.ijclab.in2p3.fr/"]}
Fractional Chern Insulators in Harper-Hofstadter Bands with Higher Chern Number
Creators: name: Möller, Gunnar
name: Cooper, Nigel R.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: The Harper-Hofstadter model provides a fractal spectrum containing topological bands of any integer Chern number, $C$. We study the many-body physics that is realized by interacting particles occupying Harper-Hofstadter bands with $|C|>1$. We formulate the predictions of Chern-Simons or composite fermion theory in terms of the filling factor, $ν$, defined as the ratio of particle density to the number of single-particle states per unit area. We show that this theory predicts a series of fractional quantum Hall states with filling factors $ν= r/(r|C| +1)$ for bosons, or $ν= r/(2r|C| +1)$ for fermions. This series includes a bosonic integer quantum Hall state (bIQHE) in $|C|=2$ bands. We construct specific cases where a single band of the Harper-Hofstadter model is occupied. For these cases, we provide numerical evidence that several states in this series are realized as incompressible quantum liquids for bosons with contact interactions.
description: v1: 7 pages, 4 figures; v2: 5+5 pages, 2+4 figures (final author formatted version)
Evolution of the central stars of young planetary nebulae
Creators: name: Hajduk, Marcin
name: van Hoof, Peter A. M.
name: Zijlstra, Albert A.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The evolution of central stars of planetary nebulae was so far documented in just a few cases. However, spectra collected a few decades ago may provide a good reference for studying the evolution of central stars using the emission line fluxes of their nebulae. We investigated evolutionary changes of the [OIII] 5007 A line flux in the spectra of planetary nebulae. We compared nebular fluxes collected during a decade or longer. We used literature data and newly obtained spectra. A grid of Cloudy models was computed using existing evolutionary models, and the models were compared with the observations. An increase of the [OIII] 5007 A line flux is frequently observed in young planetary nebulae hosting H-rich central stars. The increasing nebular excitation is the response to the increasing temperature and hardening radiation of the central stars. We did not observe any changes in the nebular fluxes in the planetary nebulae hosting late-type Wolf-Rayet (WR) central stars. This may indicate a slower temperature evolution (which may stem from a different evolutionary status) of late-[WR] stars. In young planetary nebulae with H-rich central stars, the evolution can be followed using optical spectra collected during a decade or longer. The observed evolution of H-rich central stars is consistent with the predictions of the evolutionary models provided in the literature. Late-[WR] stars possibly follow a different evolutionary path.
description: Accepted for publication in A&A
Active TLS Stack Fingerprinting: Characterizing TLS Server Deployments at Scale
Creators: name: Sosnowski, Markus
name: Zirngibl, Johannes
name: Sattler, Patrick
name: Carle, Georg
name: Grohnfeldt, Claas
name: Russo, Michele
name: Sgandurra, Daniele
Publisher: name: arXiv
Year: 2022
Subjects: subject: Networking and Internet Architecture (cs.NI)
subject: Cryptography and Security (cs.CR)
subject: FOS: Computer and information sciences

description: Active measurements can be used to collect server characteristics on a large scale. This kind of metadata can help discovering hidden relations and commonalities among server deployments offering new possibilities to cluster and classify them. As an example, identifying a previously-unknown cybercriminal infrastructures can be a valuable source for cyber-threat intelligence. We propose herein an active measurement-based methodology for acquiring Transport Layer Security (TLS) metadata from servers and leverage it for their fingerprinting. Our fingerprints capture the characteristic behavior of the TLS stack primarily caused by the implementation, configuration, and hardware support of the underlying server. Using an empirical optimization strategy that maximizes information gain from every handshake to minimize measurement costs, we generated 10 general-purpose Client Hellos used as scanning probes to create a large database of TLS configurations used for classifying servers. We fingerprinted 28 million servers from the Alexa and Majestic toplists and two Command and Control (C2) blocklists over a period of 30 weeks with weekly snapshots as foundation for two long-term case studies: classification of Content Delivery Network and C2 servers. The proposed methodology shows a precision of more than 99 % and enables a stable identification of new servers over time. This study describes a new opportunity for active measurements to provide valuable insights into the Internet that can be used in security-relevant use cases.
description: Original: https://dl.ifip.org/db/conf/tma/tma2022/tma2022-paper35.pdf Additional Material: https://active-tls-fingerprinting.github.io/
Leveraging explainable AI for enhanced decision making in humanitarian logistics: An adversarial coevolution (ACTION) framework
Creators: name: Nguyen, Su
name: O’Keefe, Greg
name: Asian, Sobhan
name: Trentelman, Kerry
name: Alahakoon, Damminda
Publisher: name: La Trobe
Year: 2023
Subjects: classificationCode: 4404
subject: Development studies
classificationCode: 4406
subject: Human geography

description: Abstract: This study examines the potential of AI-enabled wargames to enhance strategic decisionmaking in humanitarian assistance and disaster relief (HADR). We introduce an Adversarial CoevoluTION (ACTION) framework, which showcases AI’s capacity to evolve adaptable policies capable of responding to dynamic changes and adversarial actions in HADR wargame scenarios. The framework presented employs a grammar-based genetic programming algorithm to evolve intelligent and interpretable player policies. We apply the ACTION framework to a HADR wargame case study, commonly used by the Australian Defence Science and Technology Group for research purposes. The case study centres on a hypothetical disaster relief scenario in the fictional Joadia Islands, struck by a tsunami, necessitating the evacuation of dispersed civilians. Experimental results illustrate that the ACTION framework can evolve policies that adapt to environmental uncertainties and respond effectively to adversarial actions. This study offers evidence of the potential and practical application of AI-enabled technology in real-life humanitarian situations. Our findings suggest practical guidelines for humanitarian practitioners to enhance the efficiency and effectiveness of logistics planning for humanitarian aid, ultimately leading to improved outcomes in HADR scenarios.
Anomalies and Symmetry Fractionalization
Creators: name: Delmastro, Diego
name: Gomis, Jaume
name: Hsin, Po-Shen
name: Komargodski, Zohar
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study ordinary, zero-form symmetry $G$ and its anomalies in a system with a one-form symmetry $Γ$. In a theory with one-form symmetry, the action of $G$ on charged line operators is not completely determined, and additional data, a fractionalization class, needs to be specified. Distinct choices of a fractionalization class can result in different values for the anomalies of $G$ if the theory has an anomaly involving $Γ$. Therefore, the computation of the 't Hooft anomaly for an ordinary symmetry $G$ generally requires first discovering the one-form symmetry $Γ$ of the physical system. We show that the multiple values of the anomaly for $G$ can be realized by twisted gauge transformations, since twisted gauge transformations shift fractionalization classes. We illustrate these ideas in QCD theories in diverse dimensions. We successfully match the anomalies of time-reversal symmetries in $2+1d$ gauge theories, across the different fractionalization classes, with previous conjectures for the infrared phases of such strongly coupled theories, and also provide new checks of these proposals. We perform consistency checks of recent proposals about two-dimensional adjoint QCD and present new results about the anomaly of the axial $\mathbb{Z}_{2N}$ symmetry in $3+1d$ ${\cal N}=1$ super-Yang-Mills. Finally, we study fractionalization classes that lead to 2-group symmetry, both in QCD-like theories, and in $2+1d$ $\mathbb{Z}_2$ gauge theory.
description: 67 pages, 5 figures, 7 tables