cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Power of wavelets in analyses of transit and phase curves in the presence of stellar variability and instrumental noise. II. Accuracy of the transit parameters
Creators: name: Kálmán, Szilárd
name: Szabó, Gyula M.
name: Csizmadia, Szilárd
Publisher: name: arXiv
Year: 2022
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Context. Correlated noise in exoplanet light curves, such as noise from stellar activity, convection noise, and instrumental noise, distorts the exoplanet transit light curves and leads to biases in the best-fit transit parameters. An optimal fitting algorithm can provide stability against the presence of correlated noises and lead to statistically consistent results, namely, the actual biases are usually within the error interval. This is not automatically satisfied by most of the algorithms in everyday use and the testing of the algorithms is necessary. Aims. In this paper, we describe a bootstrapping-like test to handle with the general case and we apply it to the wavelet-based Transit and Light Curve Modeller (TLCM) algorithm, testing it for the stability against the correlated noise. We compare and contrast the results with regard to the FITSH algorithm, which is based on an assumption of white noise. Methods. We simulated transit light curves with previously known parameters in the presence of a correlated noise model generated by an Autoregressive Integrated Moving Average (ARIMA) process. Then we solved the simulated observations and examined the resulting parameters and error intervals. Results. We have found that the assumption of FITSH, namely, that only white noise is present, has led to inconsistencies in the results: the distribution of best-fit parameters is then broader than the determined error intervals by a factor of 3-6. On the other hand, the wavelet-based TLCM algorithm handles the correlated noise properly, leading to both properly determined parameter and error intervals that are perfectly consistent with the actual biases
description: Accepted for publication in A&A, 11 pages, 8 figures
A relação entre a munificência ambiental e o comportamento estratégico: Um estudo setorial em agências de viagens de Florianópolis e de Balneário Camboriú/SC
Creators: name: Filho, Lineu Muniz
name: Verdinelli, Miguel Angel
name: Rossetto, Carlos Ricardo
Publisher: name: Revista Turismo & Desenvolvimento
Year: 2012

description: Esta pesquisa teve por objetivo analisar a relação entre a munificência ambiental e o comportamento estratégico na perceção dos gestores de agências de viagens nos dois principais destinos turísticos do Estado de Santa Catarina/BR. Para a determinação da munificência ambiental aborda-se a teoria de Castrogiovanni (1991) e para o comportamento estratégico usa-se a tipologia de Miles e Snow (1978). O estudo teve um caráter exploratório-descritivo, sendo desenvolvido através de uma inquérito, com abordagem quantitativa. Os comportamentos estratégicos das agências foram atribuídos usando três modos diferentes e os resultados, calculados com as médias dos três modos, indicam que 26,15% das empresas têm um comportamento analista; 27,69% defensivo; 28,21% prospetor; e 17,95% reativo. As ANOVAs realizadas para a munificência, com o comportamento como preditor, foram significativas para as dimensões “crescimento e declínio” e “oportunidade e ameaça” segundo o modelo de Conant et al. (1990). Mas quando se analisou a munificência “oportunidade e ameaça” segundo o modelo de Verdinelli e Escobar (2011), obteve-se uma forte significância. Na análise das somas das médias da munificência geral predominante, a “oportunidade e ameaça” obteve a maior média, o menor desvio padrão e a menor variância.
description: Revista Turismo & Desenvolvimento, vol. 2 n.º 17/18 (2012)
Reactivity Boundaries to Separate the Fate of a Chemical Reaction Associated with Multiple Saddles
Creators: name: Nagahata, Yutaka
name: Teramoto, Hiroshi
name: Li, Chun-Biu
name: Kawai, Shinnosuke
name: Komatsuzaki, Tamiki
Publisher: name: arXiv
Year: 2013
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: Reactivity boundaries that divide the origin and destination of trajectories are crucial of importance to reveal the mechanism of reactions, which was recently found to exist robustly even at high energies for index-one saddles [Phys. Rev. Lett. 105, 048304 (2010)]. Here we revisit the concept of the reactivity boundary and propose a more general definition that can involve a single reaction associated with a bottleneck made up of higher index saddles and/or several saddle points with different indices, where the normal form theory, based on expansion around a single stationary point, does not work. We numerically demonstrate the reactivity boundary by using a reduced model system of the $H^+_5$ cation where the proton exchange reaction takes place through a bottleneck made up of two index-two saddle points and two index-one saddle points. The cross section of the reactivity boundary in the reactant region of the phase space reveals which initial conditions are effective in making the reaction happen, and thus sheds light on the reaction mechanism.
description: 12 pages, 7 figures
EMC2A-Net: An Efficient Multibranch Cross-channel Attention Network for SAR Target Classification
Creators: name: Yu, Xiang
name: Geng, Zhe
name: Huang, Xiaohua
name: Wang, Qinglu
name: Zhu, Daiyin
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: In recent years, convolutional neural networks (CNNs) have shown great potential in synthetic aperture radar (SAR) target recognition. SAR images have a strong sense of granularity and have different scales of texture features, such as speckle noise, target dominant scatterers and target contours, which are rarely considered in the traditional CNN model. This paper proposed two residual blocks, namely EMC2A blocks with multiscale receptive fields(RFs), based on a multibranch structure and then designed an efficient isotopic architecture deep CNN (DCNN), EMC2A-Net. EMC2A blocks utilize parallel dilated convolution with different dilation rates, which can effectively capture multiscale context features without significantly increasing the computational burden. To further improve the efficiency of multiscale feature fusion, this paper proposed a multiscale feature cross-channel attention module, namely the EMC2A module, adopting a local multiscale feature interaction strategy without dimensionality reduction. This strategy adaptively adjusts the weights of each channel through efficient one-dimensional (1D)-circular convolution and sigmoid function to guide attention at the global channel wise level. The comparative results on the MSTAR dataset show that EMC2A-Net outperforms the existing available models of the same type and has relatively lightweight network structure. The ablation experiment results show that the EMC2A module significantly improves the performance of the model by using only a few parameters and appropriate cross-channel interactions.
description: 15 pages, 9 figures, Submitted to IEEE Transactions on Geoscience and Remote Sensing, 2022
Eficiência relativa da oferta de alojamentos hoteleiros de gama média e alta das províncias espanholas: Uma aplicação da Análise Envolvente de Dados
Creators: name: Carlos Villamarín, Pablo De
name: Domínguez Vila, Trinidad
name: Alén González, Maria Elisa
Publisher: name: Revista Turismo & Desenvolvimento
Year: 2012

description: Ante as importantes mudanças estruturais experimentadas pelo setor turístico nas últimas décadas, que se traduziram num evidente incremento da intensidade competitiva, as possibilidades de sucesso dos destinos turísticos estão condicionadas, em grande parte, pelo grau de eficiência na utilização dos seus recursos. Esta feição, que deve ser tida em conta aquando do desenho de qualquer estratégia competitiva, é particularmente relevante no caso de um dos elementos fundamentais da oferta turística de qualquer destino, como é o alojamento, designadamente o hoteleiro. O objetivo deste trabalho é analisar, mediante a técnica da Análise Envolvente de Dados (AED), a eficiência relativa da oferta hoteleira de gama média e alta (3 a 5 estrelas de ouro) das províncias espanholas, utilizando inputs e outputs físicos, e discriminar segundo a categoria dos estabelecimentos. Para isso, recorremos aos modelos CCR e BCC, ambos na sua orientação input, o que nos permite distinguir entre os dois tipos de eficiência técnica (global) que podem apresentar as unidades analisadas: técnica pura (local) e de escala.
description: Revista Turismo & Desenvolvimento, vol. 2 n.º 17/18 (2012)
Novas evidências na relação ambiente organizacional, comportamento estratégico e desempenho: um estudo multi-caso em agências de viagens da grande Florianópolis (Santa Catarina, Brasil)
Creators: name: Rossetto, Carlos Ricardo
name: Rossetto, Adriana Marques
name: Verdinelli, Miguel Angel
name: Carvalho, Carlos Eduardo
Publisher: name: Revista Turismo & Desenvolvimento
Year: 2012

description: Este estudo comparou a relação entre ambiente organizacional, comportamento estratégico e desempenho em agências de viagens localizadas na grande Florianópolis (Santa Catarina/SC) – Brasil, a partir da perceção dos seus gestores. Optou-se por uma abordagem quantitativa e por uma estratégia de pesquisa na aplicação de inquéritos por questionário utilizando métodos exploratórios multivariados. Como dimensões de análise do ambiente, recorreu-se à tipologia simples-complexo ou estático-dinâmico de Duncan (1972), a partir do número de fatores (frequência) e do grau de variação destes (intensidade). Para tipificar o comportamento, utilizou-se a tipologia de Miles e Snow (1978). O ambiente dinâmico-complexo foi o mais percebido pelos gestores, bem como a frequência dos fatores “legislação” e “tecnologia”, e a intensidade de mudanças do fator “economia”. A variável de controle “escolaridade” foi relacionada com a intensidade das mudanças, e a “idade” com a frequência das mudanças. Os gestores das agências de viagens adotam, predominantemente, os comportamentos prospetor e defensivo, embora gestores com maior idade adotem comportamentos analíticos. Os que percebem elevada frequência de mudanças, tendam a adotar comportamentos defensivos e o desempenho relaciona-se com o comportamento reativo. A relevância deste estudo reside no fato de este em trazer novas evidências ao entendimento de como as organizações interpretam o ambiente e se comportam em seus setores de atuação.
description: Revista Turismo & Desenvolvimento, vol. 2 n.º 17/18 (2012)
The Casal de’ Pazzi mammalian fauna: biochronological and paleoecological notes, and research perspectives
Creators: name: Palombo, Maria Rita
Publisher: name: Journal of Mediterranean Earth Sciences
Year: 2023

description: This note critically reviews the biochronological range of the mammalian taxa identified thus far in the faunal assemblage found in the musealized sector of the late Middle Pleistocene fluvial deposit of Casal de’ Pazzi (CdP), evaluates the similarity among the CdP fauna and that of some selected local faunal assemblages from Latium and surrounding area, and summarizes and updates our knowledge about the paleoecological hints provided by the herbivore remains. An attempt to compare CdP the ecological structure of the CdP large mammal fauna with that of the selected late Middle Pleistocene (MIS 11-MIS 7)sites, mainly from Latium, failed to provide any compelling results. This conceivably depends on the low richness of some faunal assemblages, some monotony of their taxonomical composition combined with the commonness of some taxa recorded in almost all local assemblages, and the lack of studies of the autecology of taxa recorded at each site. Accordingly, this note gives a synthesis of the principal studies that, in the future, could shed light on matters either not yet scrutinized or still unsolved. The potential results of integrated multidisciplinary research could contribute to enhancing our knowledge about the Latium mammalian fauna’s evolutionary dynamics in the context of the evolution of the SW European large mammal fauna during the late Middle Pleistocene.
description: Journal of Mediterranean Earth Sciences, Vol. 15 (2023): In progress
Zum Problem der Flüchtlingsdiaspora im Gebiet der evangelisch-lutherischen Kirche in Bayern
Creators: name: Probst, Gottfried
Publisher: name: Lutherische Kirche in der Welt
Year: 1970

description: Lutherische Kirche in der Welt, Bd. 5 (1951): Jahrbuch des Martin-Luther-Bundes, Band 5
title: Die Versuchung; [1848]
title: Ein Beispiel: Wie sich die bösen Feinde unter den Abgeordneten herumschleichen, um ihnen einzuflüstern, dass wenn der Waffenstillstand nicht genehmigt würde, werde der Reichsverweser sein Amt niederlegen (Welches sich als reine Lüge herausstellte.)
titleType: Subtitle
Creators: name: (:Unav)
Publisher: name: Universitätsbibliothek der Ludwig-Maximilians-Universität München
Year: 2018

description: Vorlageform der Veröffentlichungsangabe: Verlag von J.B. Simon in Frankfurt a/m
A Governança sonhada para o Turismo: uma análise sobre o voucher único de Barreirinhas (Maranhão, Brasil), a partir da visão dos empresários do setor turístico
Creators: name: Costa, Helena Araújo
name: Silva, David Leonardo Bouças Da
name: Nascimento, Elimar Pinheiro Do
Publisher: name: Revista Turismo & Desenvolvimento
Year: 2012

description: O artigo analisa a implementação do modelo de gestão conhecido como voucher único do destino turístico de Barreirinhas, Maranhão (Brasil), a partir da visão dos empresários locais do turismo. O modelo foi inspirado no sistema existente em Bonito, Mato Grosso do Sul (Brasil), considerado um destino de ecoturismo de excelência no Brasil. O referencial teórico está centrado no conceito de governança para a gestão de destinos turísticos. O estudo, de caráter qualitativo, utiliza 10 entrevistas semiestruturadas com empresários e executivos de negócios ligados a atividades do turismo na localidade. Nos resultados encontram-se alguns pontos positivos da implementação deste modelo. Contudo, prevalecem os pontos negativos: (a) Estratégia impositiva do governo municipal na implementação do voucher; (b) Carência de informações no uso da arrecadação; (c) Prejuízos às empresas por conta da responsabilidade de cobrança do voucher; (d) Processo dispendioso para as agências de receptivo na sua operacionalização; (e) Fiscalização deficiente na cobrança do voucher; (f) Sistema de cobrança único é desigual.
description: Revista Turismo & Desenvolvimento, vol. 2 n.º 17/18 (2012)
Baryon stopping in the Color Glass Condensate formalism: A phenomenological study
Creators: name: Duraes, F. O.
name: Giannini, A. V.
name: Goncalves, V. P.
name: Navarra, F. S.
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The net-baryon production at forward rapidities is investigated considering the Color Glass Condensate formalism. We assume that at large energies the coherence of the projectile quarks is lost and that the leading baryon production mechanism changes from recombination to independent fragmentation. The phenomenological implications for net-baryon production in $pp/pA/AA$ collisions are analysed and predictions for LHC energies are presented.
description: 9 pages, 8 figures
An elementary analysis of ridge regression with random design
Creators: name: Mourtada, Jaouad
name: Rosasco, Lorenzo
Publisher: name: arXiv
Year: 2022
Subjects: subject: Statistics Theory (math.ST)
subject: Machine Learning (cs.LG)
subject: Machine Learning (stat.ML)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: In this note, we provide an elementary analysis of the prediction error of ridge regression with random design. The proof is short and self-contained. In particular, it bypasses the use of Rudelson's deviation inequality for covariance matrices, through a combination of exchangeability arguments, matrix perturbation and operator convexity.
description: fixes a typo, small changes; 9 pages
Adaptive Domain Generalization via Online Disagreement Minimization
Creators: name: Zhang, Xin
name: Chen, Ying-Cong
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Deep neural networks suffer from significant performance deterioration when there exists distribution shift between deployment and training. Domain Generalization (DG) aims to safely transfer a model to unseen target domains by only relying on a set of source domains. Although various DG approaches have been proposed, a recent study named DomainBed, reveals that most of them do not beat the simple Empirical Risk Minimization (ERM). To this end, we propose a general framework that is orthogonal to existing DG algorithms and could improve their performance consistently. Unlike previous DG works that stake on a static source model to be hopefully a universal one, our proposed AdaODM adaptively modifies the source model at test time for different target domains. Specifically, we create multiple domain-specific classifiers upon a shared domain-generic feature extractor. The feature extractor and classifiers are trained in an adversarial way, where the feature extractor embeds the input samples into a domain-invariant space, and the multiple classifiers capture the distinct decision boundaries that each of them relates to a specific source domain. During testing, distribution differences between target and source domains could be effectively measured by leveraging prediction disagreement among source classifiers. By fine-tuning source models to minimize the disagreement at test time, target domain features are well aligned to the invariant feature space. We verify AdaODM on two popular DG methods, namely ERM and CORAL, and four DG benchmarks, namely VLCS, PACS, OfficeHome, and TerraIncognita. The results show AdaODM stably improves the generalization capacity on unseen domains and achieves state-of-the-art performance.
description: 11 pages, 4 figures
Riscos percebidos por turistas e estratégias de redução de risco utilizadas por ambulantes de praia no Brasil: uma análise na perspectiva dos vendedores de alimentos não industrializados
Creators: name: Marques, Rafaela
name: Kovacs, Michelle
name: Cabral, Emily
name: Faro, Rodrigo
name: Gomes, Anderson
name: Barbosa, Maria De Lourdes De Azevedo
Publisher: name: Revista Turismo & Desenvolvimento
Year: 2012

description: Diante da circunstância de incerteza, os consumidores podem utilizar diferentes meios para minimizar os riscos que percebem como forma de efetuar suas aquisições. Essas ações são conceituadas como estratégias de redução de riscos. A proposta desta investigação traz à tona um assunto pouco explorado, os riscos percebidos pelos turistas que consomem alimentos não industrializados, sob a ótica dos ambulantes de praia, além da identificação das estratégias utilizadas pelos ambulantes locais para minimizar os riscos que os seus clientes percebem. A abordagem metodológica utilizada na pesquisa foi qualitativa, utilizando-se entrevistas semi-estruturadas com posterior análise de conteúdo. Os principais achados apontam que os ambulantes identificam a percepção dos riscos pelos turistas e que as principais tipologias mencionadas são: risco financeiro, físico e de desempenho, e, para reduzir esses medos, os vendedores ambulantes tendem a utilizar as seguintes estratégias visando minimizar a percepção de riscos por parte dos consumidores: imagem do vendedor, garantias, experimentação/amostra grátis.
description: Revista Turismo & Desenvolvimento, vol. 2 n.º 17/18 (2012)
Modelos e Processos de Gestão em Negócios Turísticos. Tendências num contexto em mudança
Creators: name: Gustavo, Nuno Silva
Publisher: name: Revista Turismo & Desenvolvimento
Year: 2012

description: No despertar do século XXI as mudanças registadas ao nível estrutural têm sustentado o desenvolvimento de uma nova realidade competitiva no turismo, levando as empresas do setor, no domínio dos diferentes negócios da atividade (Hotelaria, Restauração, Aviação, etc.), a adotar novos modelos e processos de gestão. Neste sentido, o presente artigo visa não ser um fim em si mesmo, mas um ponto de partida para um conjunto de reflexões, hipóteses e futuras linhas de investigação, materializando-se o seu objectivo na identificação de tendências genéricas para a gestão dos negócios turísticos. O modelo de análise concebido para a presente investigação sustenta-se numa matriz de abordagem de natureza estratégica. Num primeiro momento o artigo identifica e reflete de forma geral as principais premissas promotoras do novo ambiente contextual dos negócios turísticos, tendo a matriz STEEP analysis como referência. Após caracterizar o referido cenário, o artigo debruça-se sobre as mudanças fundamentais ao nível do ambiente transacional, expondo as principais alterações e tendências registadas no domínio da procura e da oferta turística. Por fim, o artigo apresenta um conjunto de reflexões e tendências para possíveis linhas de investigação, na ótica dos modelos e processos de gestão dos negócios turísticos. No sentido de sustentar as tendências sugeridas, as quais são suportadas num quadro de revisão teórica do presente estudo e relatórios elaborados por diferentes empresas, entidades e consultoras, são apresentados diferentes exemplos e casos de estudo, tendo por base, empresas de referência do trade nacional e internacional, corporizando o quadro teórico apresentado. A sistematização da investigação bibliográfica funcionou também como um suporte para enquadrar e aferir a problemática de estudo, procurando-se proceder a uma análise correlativa entre as dimensões teóricas do modelo de gestão e as dinâmicas empíricas provenientes dos vários estudos de caso.
description: Revista Turismo & Desenvolvimento, vol. 2 n.º 17/18 (2012)
Der Unterstaatssecretair Bassermann hat Audienz beim König und findet ihn deutscher gesinnt als er es gehofft und sieht mit hoher Freude dass derselbe entschlossen ist: Preussen u. Deutschland mit der wahren Freiheit zu beglücken.; [1848?]
Creators: name: (:Unav)
Publisher: name: Universitätsbibliothek der Ludwig-Maximilians-Universität München
Year: 2018

description: Taf. 4
IDLat: An Importance-Driven Latent Generation Method for Scientific Data
Creators: name: Shen, Jingyi
name: Li, Haoyu
name: Xu, Jiayi
name: Biswas, Ayan
name: Shen, Han-Wei
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Graphics (cs.GR)
subject: FOS: Computer and information sciences

description: Deep learning based latent representations have been widely used for numerous scientific visualization applications such as isosurface similarity analysis, volume rendering, flow field synthesis, and data reduction, just to name a few. However, existing latent representations are mostly generated from raw data in an unsupervised manner, which makes it difficult to incorporate domain interest to control the size of the latent representations and the quality of the reconstructed data. In this paper, we present a novel importance-driven latent representation to facilitate domain-interest-guided scientific data visualization and analysis. We utilize spatial importance maps to represent various scientific interests and take them as the input to a feature transformation network to guide latent generation. We further reduced the latent size by a lossless entropy encoding algorithm trained together with the autoencoder, improving the storage and memory efficiency. We qualitatively and quantitatively evaluate the effectiveness and efficiency of latent representations generated by our method with data from multiple scientific visualization applications.
description: 11 pages, 12 figures, Proc. IEEE VIS 2022
Quantum simulations of a particle in one-dimensional potentials using NMR
Creators: name: Shankar, Ravi
name: Hegde, Swathi S.
name: Mahesh, T. S.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: A classical computer simulating Schrodinger dynamics of a quantum system requires resources which scale exponentially with the size of the system, and is regarded as inefficient for such purposes. However, a quantum computer made up of a controllable set of quantum particles has the potential to efficiently simulate other quantum systems of matching dimensions. In this work we studied quantum simulations of single particle Schrodinger equation for certain one-dimensional potentials. In particular, we report the following cases: (i) spreading of wave-function of a free-particle, (ii) evolution of a particle in a potential-well, and (iii) reflection of a particle from a potential-barrier. Using a five-qubit NMR system, we achieve space discretization with four qubits, and the other qubit is used for preparation of initial states as well as measurement of spatial probabilities. The experimental relative probabilities compare favorably with the theoretical values, thus effectively mimicking a small-scale quantum simulator.
description: 7 pages, 8 figures
title: Archeology in “stone line” sedimentary environments. A methodological approach and results based on the Early and Middle Pleistocene sites at Melka Kunture (Upper Awash, Ethiopia)
Creators: name: Méndez-Quintas, Eduardo
name: Melis, Rita T.
name: Altamura, Flavio
name: Di Bianco, Luca
name: Panera, Joaquín
name: Ruta, Giancarlo
name: Serodio Domínguez, Andrea
name: Sánchez-Dehesa Galán, Sol
name: Mussi, Margherita
Publisher: name: Journal of Mediterranean Earth Sciences
Year: 2023

description: Sites in sedimentary cobble-bed environments, which are quite common in African Pleistocene sites, are routinely reported as extensively affected by sedimentary processes. The Gombore II and Garba I sites (Melka Kunture, Ethiopia), both in a cobble-bed setting, allow a different approach. Using archive data from previous excavations and new field observations, we analyzed size ranges, orientation, sedimentary fabrics, and spatial distribution patterns at both sites as well as in a nearby present-day stream deposit, to make comparisons and assess any similarity in sedimentary setting. The results suggest that Gombore II and Garba I have been subjected to a low degree of sedimentary disturbance, without severe taphonomic effects on the archeological assemblages.
description: Journal of Mediterranean Earth Sciences, Vol. 15 (2023): In progress
A Holographic Model of the Kondo Effect
Creators: name: Erdmenger, Johanna
name: Hoyos, Carlos
name: O'Bannon, Andy
name: Wu, Jackson
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We propose a model of the Kondo effect based on the Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence, also known as holography. The Kondo effect is the screening of a magnetic impurity coupled anti-ferromagnetically to a bath of conduction electrons at low temperatures. In a (1+1)-dimensional CFT description, the Kondo effect is a renormalization group flow triggered by a marginally relevant (0+1)-dimensional operator between two fixed points with the same Kac-Moody current algebra. In the large-N limit, with spin SU(N) and charge U(1) symmetries, the Kondo effect appears as a (0+1)-dimensional second-order mean-field transition in which the U(1) charge symmetry is spontaneously broken. Our holographic model, which combines the CFT and large-N descriptions, is a Chern-Simons gauge field in (2+1)-dimensional AdS space, AdS3, dual to the Kac-Moody current, coupled to a holographic superconductor along an AdS2 subspace. Our model exhibits several characteristic features of the Kondo effect, including a dynamically generated scale, a resistivity with power-law behavior in temperature at low temperatures, and a spectral flow producing a phase shift. Our holographic Kondo model may be useful for studying many open problems involving impurities, including for example the Kondo lattice problem.
description: 42 pages, 10 eps files in 6 figures
Quantum algorithms from fluctuation theorems: Thermal-state preparation
Creators: name: Holmes, Zoe
name: Muraleedharan, Gopikrishnan
name: Somma, Rolando D.
name: Subasi, Yigit
name: Şahinoğlu, Burak
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Fluctuation theorems provide a correspondence between properties of quantum systems in thermal equilibrium and a work distribution arising in a non-equilibrium process that connects two quantum systems with Hamiltonians $H_0$ and $H_1=H_0+V$. Building upon these theorems, we present a quantum algorithm to prepare a purification of the thermal state of $H_1$ at inverse temperature $β\ge 0$ starting from a purification of the thermal state of $H_0$. The complexity of the quantum algorithm, given by the number of uses of certain unitaries, is $\tilde {\cal O}(e^{β(Δ\! A- w_l)/2})$, where $Δ\! A$ is the free-energy difference between $H_1$ and $H_0,$ and $w_l$ is a work cutoff that depends on the properties of the work distribution and the approximation error $ε>0$. If the non-equilibrium process is trivial, this complexity is exponential in $β\|V\|$, where $\|V\|$ is the spectral norm of $V$. This represents a significant improvement of prior quantum algorithms that have complexity exponential in $β\|H_1\|$ in the regime where $\|V\|\ll \|H_1\|$. The dependence of the complexity in $ε$ varies according to the structure of the quantum systems. It can be exponential in $1/ε$ in general, but we show it to be sublinear in $1/ε$ if $H_0$ and $H_1$ commute, or polynomial in $1/ε$ if $H_0$ and $H_1$ are local spin systems. The possibility of applying a unitary that drives the system out of equilibrium allows one to increase the value of $w_l$ and improve the complexity even further. To this end, we analyze the complexity for preparing the thermal state of the transverse field Ising model using different non-equilibrium unitary processes and see significant complexity improvements.
description: 54 pages, 11 figures
Critical competitiveness factors for hospitality: a look into the future
Creators: name: Varum, Celeste
name: Eusébio, Celeste
name: Melo, Carla
name: Alvarenga, António
name: Carvalho, Paulo Soeiro De
Publisher: name: Journal of Tourism & Development
Year: 2012

description: Taking as staring point four possible scenarios for the Portuguese hospitality industry, we investigated which would be the critical factors of competitiveness for hotels in a 2020 time horizon. The results are innovative and challenging with practical implications for managers. The work is also valuable for the international foresight community by discussing the method and addressing some drawbacks of the scenario process.
description: Journal of Tourism & Development, vol. 2 n.º 17/18 (2012)
On direct observation of millicharged particles at $c$-$τ$ factories and other $e^+e^-$-colliders
Creators: name: Gorbunov, Dmitry
name: Kalashnikov, Dmitry
name: Pakhlov, Pavel
name: Uglov, Timofey
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Hypothetical particles with tiny electric charges (millicharged particles or MCPs) can be produced in electron-positron annihilation if kinematically allowed. Typical searches for them at $e^+e^-$ colliders exploit a signature of a single photon with missing energy carried away by the undetected MCP pair. We put forward an idea to look alternatively for MCP energy deposits inside a tracker, which is a direct observation. The new signature is relevant for non-relativistic MCPs, and we illustrate its power on the example of the $c$-$τ$ factory, where we argued that the corresponding searches may be background-free. We find that it can probe the MCP charge down to $3\times10^{-3}$ of the electron charge for the MCP masses in ${\cal O}(5)$ MeV vicinity of each energy beam value where the factory will collect a luminosity of 100 fb$^{-1}$ in one year. This mass region is unreachable with the searches for missing energy and single photon.
description: 12 pages, 3 figures; v2: the background-free signature is introduced
Weak-localization approach to a 2D electron gas with a spectral node
Creators: name: Ziegler, K.
name: Sinner, A.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We study a weakly disordered 2D electron gas with two bands and a spectral node within the weak-localization approach and compare its results with those of Gaussian fluctuations around the self-consistent Born approximation. The appearance of diffusive modes depends on the type of disorder. In particular, we find for a random gap a diffusive mode only from ladder contributions, whereas for a random scalar potential the diffusive mode is created by ladder and by maximally crossed contributions. The ladder (maximally crossed) contributions correspond to fermionic (bosonic) Gaussian fluctuations. We calculate the conductivity corrections from the density--density Kubo formula and find a good agreement with the experimentally observed V-shape conductivity of graphene.
description: 10 pages, 2 figures
Newly identified YSO candidates towards the LDN 1188
Creators: name: Marton, Gábor
name: Verebélyi, Erika
name: Kiss, Csaba
name: Smidla, József
Publisher: name: arXiv
Year: 2013
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present an analysis of Young Stellar Object (YSO) candidates towards the LDN 1188 molecular cloud. The YSO candidates were selected from the WISE all-sky catalogue, based on a statistical method. We found 601 candidates in the region, and classified them as Class I, Flat and Class II YSOs. Groups were identified and described with the Minimal Spanning Tree (MST) method. Previously identified molecular cores show evidence of ongoing star formation at different stages throughout the cloud complex.
description: 4 pages, 4 figures, 2 tables
Fully probabilistic deep models for forward and inverse problems in parametric PDEs
Creators: name: Vadeboncoeur, Arnaud
name: Akyildiz, Ömer Deniz
name: Kazlauskaite, Ieva
name: Girolami, Mark
name: Cirak, Fehmi
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (stat.ML)
subject: Machine Learning (cs.LG)
subject: Numerical Analysis (math.NA)
subject: Computation (stat.CO)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: We introduce a physics-driven deep latent variable model (PDDLVM) to learn simultaneously parameter-to-solution (forward) and solution-to-parameter (inverse) maps of parametric partial differential equations (PDEs). Our formulation leverages conventional PDE discretization techniques, deep neural networks, probabilistic modelling, and variational inference to assemble a fully probabilistic coherent framework. In the posited probabilistic model, both the forward and inverse maps are approximated as Gaussian distributions with a mean and covariance parameterized by deep neural networks. The PDE residual is assumed to be an observed random vector of value zero, hence we model it as a random vector with a zero mean and a user-prescribed covariance. The model is trained by maximizing the probability, that is the evidence or marginal likelihood, of observing a residual of zero by maximizing the evidence lower bound (ELBO). Consequently, the proposed methodology does not require any independent PDE solves and is physics-informed at training time, allowing the real-time solution of PDE forward and inverse problems after training. The proposed framework can be easily extended to seamlessly integrate observed data to solve inverse problems and to build generative models. We demonstrate the efficiency and robustness of our method on finite element discretized parametric PDE problems such as linear and nonlinear Poisson problems, elastic shells with complex 3D geometries, and time-dependent nonlinear and inhomogeneous PDEs using a physics-informed neural network (PINN) discretization. We achieve up to three orders of magnitude speed-up after training compared to traditional finite element method (FEM), while outputting coherent uncertainty estimates.
Schöningen: a reference site for the Middle Pleistocene
Creators: name: Serangeli, Jordi
name: Verheijen, Ivo
name: Rodríguez-Álvarez, Bárbara
name: Altamura, Flavio
name: Bigga, Gerlinde
name: Schoch, Werner H.
name: Urban, Brigitte
name: Van Kolfschoten, Thijs
name: Venditti, Flavia
name: Conard, Nicholas J.
Publisher: name: Journal of Mediterranean Earth Sciences
Year: 2023

description: Due to the exceptional preservation conditions, as well as the number and significance of the finds discovered, Schöningen in northern Germany stands out as a uniquely informative Middle Pleistocene site-complex. More than 20 archeological and 10 paleontological sites embedded in the shoreline sediments of a paleolake have preserved natural and anthropogenically modified wood, bones, and stones. A combination of data acquired from geological, stratigraphic, palynological, and faunal analysis, coupled with various direct dating methods, have indicated an age of ca. 300,000 years BP, corresponding to MIS 9. The lithic technology corresponds to the late Lower Paleolithic and is therefore consistent with these dates. This article gives an overview of the site-complex, of the most important discoveries at Schöningen, and describes the discovery of a nearly complete straight-tusked elephant skeleton (Palaeoloxodon antiquus) in an archeological context. Contextualized among contemporaneous archeological discoveries, the finds at Schöningen contribute significantly to our understanding of the late Lower Paleolithic in Europe.
description: Journal of Mediterranean Earth Sciences, Vol. 15 (2023): In progress
Zero-energy states in graphene quantum dot with wedge disclination
Creators: name: Bouhlal, Ahmed
name: Jellal, Ahmed
name: Shah, Nurisya Mohd
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We investigate the effects of wedge disclination on charge carriers in circular graphene quantum dots subjected to a magnetic flux. Using the asymptotic solutions of the energy spectrum for large arguments, we approximate the scattering matrix elements, and then study the density of states. It is found that the density of states shows several resonance peaks under various conditions. In particular, it is shown that the wedge disclination is able to change the amplitude, width, and positions of resonance peaks.
description: 10 pages, 10 figures
Regional Innovation Systems and Tourism: a Conceptual Approach
Creators: name: Brandão, Filipa
name: Costa, Carlos Manuel Martins Da
Publisher: name: Journal of Tourism & Development
Year: 2012

description: This article aims at providing a conceptual framework for the analysis of regional innovation in tourism, linking the development of tourism destinations and geography of innovation fields of study. It discusses the evolution of innovation models towards interactive processes that highlight the importance of regions and regional actors in innovation and territorial development. Considering the nature and dynamics of tourism industry, Regional Innovation Systems theory was considered to be the most appropriated for this analysis. Bearing this in mind, the concept was applied to tourism destinations through: (i) the identification of tourism actors; (ii) the definition of tourism regions; (iii) the analysis of innovation networks in tourism innovation; and (iv) knowledge creation and transfer in tourism practices as crucial innovation processes. This analysis resulted in a conceptual model of a Regional Tourism Innovation System, which contributes to the understanding of the dynamics of tourism systemic innovation (helping the design of innovation policies) and provides a model for empirical research on tourism innovation.
description: Journal of Tourism & Development, vol. 2 n.º 17/18 (2012)
Emergent Hyper-Magic Manifold in Twisted Kitaev Bilayers
Creators: name: Haskell, Samuel
name: Principi, Alessandro
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Kitaev quantum spin liquids have been the focus of intense research effort thanks to the discovery of various materials (e.g., RuCl3) that approximate their intriguing physics. In this paper we construct a mean-field approximation for a moir`e superlattice emerging in twisted Kitaev bilayers in terms of solutions of commensurate bilayers. We show that the band structure of deconfined spinons, defined on the mini-Brillouin zone of the superlattice, is greatly modified. The system exhibits a hyper-magic manifold: a series of nearly perfectly-flat bands appear at energies above the lowest gap, exhibiting a very large (spinon) density of states that could potentially be probed experimentally. Intriguingly, flat-band eigenstates exhibit a localization akin to wavefunctions of Kagome lattices.
description: 5 pages + 3 for references, 3 figures
On instability of a generic compressible two-fluid model in $\mathbb R^3$
Creators: name: Wu, Guochun
name: Yao, Lei
name: Zhang, Yinghui
Publisher: name: arXiv
Year: 2022
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: We are concerned with the instability of a generic compressible two-fluid model in the whole space $\mathbb{R}^3$, where the capillary pressure $f(α^-ρ^-)=P^+-P^-\neq 0$ is taken into account. For the case that the capillary pressure is a strictly decreasing function near the equilibrium, namely, $f'(1)<0$, Evje-Wang-Wen established global stability of the constant equilibrium state for the three-dimensional Cauchy problem under some smallness assumptions. Recently, Wu-Yao-Zhang proved global stability of the constant equilibrium state for the case $P^+=P^-$ (corresponding to $f'(1)=0$). In this work, we investigate the instability of the constant equilibrium state for the case that the capillary pressure is a strictly increasing function near the equilibrium, namely, $f'(1)>0$. First, by employing Hodge decomposition technique and making detailed analysis of the Green's function for the corresponding linearized system, we construct solutions of the linearized problem that grow exponentially in time in the Sobolev space $H^k$, thus leading to a global instability result for the linearized problem. Moreover, with the help of the global linear instability result and a local existence theorem of classical solutions to the original nonlinear system, we can then show the instability of the nonlinear problem in the sense of Hadamard by making a delicate analysis on the properties of the semigroup. Therefore, our result shows that for the case $f'(1)>0$, the constant equilibrium state of the two-fluid model is linearly globally unstable and nonlinearly locally unstable in the sense of Hadamard, which is in contrast to the cases $f'(1)<0$ and $P^+=P^-$ (corresponding to $f'(1)=0$) where the constant equilibrium state of the two--fluid model is nonlinearly globally stable.
description: 17. arXiv admin note: substantial text overlap with arXiv:2204.10706, arXiv:2108.06974, arXiv:2010.11509
Competitiveness of Tourism Destinations and Opportunities for Innovation from the Regional Competencies
Creators: name: Mazaro, Rosana Mara
Publisher: name: Journal of Tourism & Development
Year: 2012

description: The experience economy brings an environment of opportunity for creating competitive advantages in tourism. In this context, the quest for innovation has become the main challenge for the industry and attracts interest for studies on the subject. Even in an exploratory phase, such studies allow a first fundamental differentiation between an approach that focuses on studies of innovation in business environments and a more recent approach that perceives innovation in tourism from a regional perspective. This paper is based on the regional perspective of innovation in tourism and proposes to contribute to the definition and theoretical characterization of what can be innovation in tourism destinations. The research uses a systematic literature search and documentation analysis for the comparison between concepts, characteristics and attributes of competitiveness for destinations that reflect the determinants of the experience economy, and the concepts, characteristics and attributes that identify and characterize countries and regions with innovative profile, or able to foster innovation. Comparison between results in a typology that can serve as a conceptual basis for guiding applied research on issues of innovation in tourism from the regional vision, and to contribute to the understanding of the factors determining the competitiveness of tourist destinations based on the imperatives of economy of the experiment.
description: Journal of Tourism & Development, vol. 2 n.º 17/18 (2012)
History Based Coalition Formation in Hedonic Context Using Trust
Creators: name: Ghaffarizadeh, Ahmadreza
name: Allan, Vicki H.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Multiagent Systems (cs.MA)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: In this paper we address the problem of coalition formation in hedonic context. Our modelling tries to be as realistic as possible. In previous models, once an agent joins a coalition it would not be able to leave the coalition and join the new one; in this research we made it possible to leave a coalition but put some restrictions to control the behavior of agents. Leaving or staying of an agent in a coalition will affect on the trust of the other agents included in this coalition. Agents will use the trust values in computing the expected utility of coalitions. Three different risk behaviors are introduced for agents that want to initiate a coalition. Using these risk behaviors, some simulations are made and results are analyzed.
description: 8 pages