3,834 research outputs found
A ddc-type condition beyond the K\"ahler realm
This paper introduces a generalization of the ddc-condition for complex
manifolds. Like the ddc-condition, it admits a diverse collection of
characterizations, and is robust under numerous geometric constructions. Most
notably, it is an open property with respect to small deformations. The
condition is satisfied by a wide range of complex manifolds including all
compact complex surfaces and all compact Vaisman manifolds. These last examples
are studied in detail, where the entire bicomplex structure is determined,
yielding several corollaries of geometric interest.Comment: Comments welcome
Inferring muscle functional roles of the ostrich pelvic limb during walking and running using computer optimization
Owing to their cursorial background, ostriches (Struthio camelus) walk and run with high metabolic economy, can reach very fast running speeds and quickly execute cutting manoeuvres. These capabilities are believed to be a result of their ability to coordinate muscles to take advantage of specialized passive limb structures. This study aimed to infer the functional roles of ostrich pelvic limb muscles during gait. Existing gait data were combined with a newly developed musculoskeletal model to generate simulations of ostrich walking and running that predict muscle excitations, force and mechanical work. Consistent with previous avian electromyography studies, predicted excitation patterns showed that individual muscles tended to be excited primarily during only stance or swing. Work and force estimates show that ostrich gaits are partially hip-driven with the bi-articular hip–knee muscles driving stance mechanics. Conversely, the knee extensors acted as brakes, absorbing energy. The digital extensors generated large amounts of both negative and positive mechanical work, with increased magnitudes during running, providing further evidence that ostriches make extensive use of tendinous elastic energy storage to improve economy. The simulations also highlight the need to carefully consider non-muscular soft tissues that may play a role in ostrich gait
Characterization of a multimode coplanar waveguide parametric amplifier
We characterize a novel Josephson parametric amplifier based on a
flux-tunable quarter-wavelength resonator. The fundamental resonance frequency
is ~1GHz, but we use higher modes of the resonator for our measurements. An
on-chip tuning line allows for magnetic flux pumping of the amplifier. We
investigate and compare degenerate parametric amplification, involving a single
mode, and nondegenerate parametric amplification, using a pair of modes. We
show that we reach quantum-limited noise performance in both cases, and we show
that the added noise can be less than 0.5 added photons in the case of low
gain
Single-shot Readout of a Superconducting Qubit using a Josephson Parametric Oscillator
We propose and demonstrate a new read-out technique for a superconducting
qubit by dispersively coupling it to a Josephson parametric oscillator. We
employ a tunable quarter-wavelength superconducting resonator and modulate its
resonant frequency at twice its value with an amplitude surpassing the
threshold for parametric instability. We map the qubit states onto two distinct
states of classical parametric oscillation: one oscillating state, with
photons in the resonator, and one with zero oscillation amplitude.
This high contrast obviates a following quantum-limited amplifier. We
demonstrate proof-of-principle, single-shot readout performance, and present an
error budget indicating that this method can surpass the fidelity threshold
required for quantum computing.Comment: 11 pages, 5 figure
Zelo pelo serviço real : ações de ouvidores régios nas comarcas de São Paulo e de Paranaguá (primeira metade do século XVIII)
Orientador : Prof. Dr. Antonio Cesar de Almeida SantosAutor não autorizou a divulgação do arquivo digitalTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Humanas, Programa de Pós-Graduação em História. Defesa: Curitiba, 26/02/2014Inclui referências : fls. 230-247Área de concentração :Resumo: Esta pesquisa buscou observar como as políticas do Império Ultramarino Português comungaram com as estratégias individuais dos agentes régios enviados para a América. Utilizando-se como objeto de pesquisa os ouvidores régios que atuaram na Ouvidoria de São Paulo e Paranaguá durante a primeira metade do século XVIII, discutiu-se como estes agentes régios utilizaram a estrutura administrativa portuguesa para seu "ganho pessoal", observando, dentre outros aspectos, a possível ascensão social. Deve-se ter claro que para observar a relação entre o agente régio e o corpo social identificamos a existência de determinadas características que lhe davam certa distinção no interior deste corpo, ao possuir uma intrínseca relação com a administração central lusitana, o que lhe provia, concomitantemente, uma relação com o rei. Estes agentes régios devotavam sua confiança na estrutura administrativa da Coroa, reconhecendo a autoridade do rei como soberano, e, por sua vez, utilizavam do poder politico régio com o intuito de ascender socialmente. O rei, por outro lado, buscava por meio desses agentes assegurar suas prerrogativas no ultramar. Desta forma, estabeleceu-se uma hierarquia no ultramar português, formando grandes redes governativas. Para esta pesquisa foram utilizadas como fontes as mercês régias, as leituras de bacharéis, a documentação produzida pelos ouvidores e das ordens régias no período delimitado. Palavras-chave: Império Ultramarino Português; Ações administrativas; Ouvidores régios; Ouvidoria de São Paulo e Paranaguá.Abstract: This research aims at identifying the ways in which the politics of the Portuguese Overseas Empire were in keeping with the individual strategies of the regal agents sent to America. Using as research material the regal ombudsmen that acted in the Ombudsmans ["Ouvidoria"] of São Paulo and Paranaguá during the first half of the 18th century, this work discusses how these regal agents used the Portuguese administrative structure for their own personal benefit, observing, among other aspects, their possible social ascension. In order to observe the relationship between the regal agent and the social structure, we identified the existence of certain characteristics that provided them with a certain distinction inside that social structure through an intrinsic connection with the Lusitanian central administration, which also provided, concomitantly, a relationship with the King. These regal agents devoted their trust to the administrative structure of the Crown, recognizing the authority of the King as a sovereign, and, at the same time, used the regal political power so as to ascend in society. The King, on the other hand, sought to enhance his prerogatives overseas by means of these agents. Thus, a hierarchy in the Portuguese overseas dominion was established through the formation of major gubernatorial networks. We used as source for this research the regal mercies ["mercês"], the readings of the bachelors ["bacharéis"], the documentation produced by the ombudsmen and the regal orders in the period. Keywords: Portuguese Overseas Empire; Administrative acts; Regal ombudsmen; Ombudsmans of São Paulo and ParanaguáRésumé: Cette recherche vise à observer la façon dont les politiques de l'Empire Portugais d'Outre-Mer ont partagé avec les stratégies individuelles des agents royaux envoyés en Amérique. En utilisant comme objet de recherche les médiateurs royaux qui ont agi dans le Service de Médiation de Sao Paulo et Paranagua au cours de la première moitié du XVIIIè siècle, il a été discuté la façon dont ces agents royaux ont utilisé la structure administrative portugaise pour leur " gain personnel ", en observant, entre autres aspects, la possible mobilité sociale. Il devrait être clair que, pour observer la relation entre l'agent royal et le corps social, on identifie l'existence de quelques caractéristiques qui lui donnaient une certaine distinction au sein de cet organisme, vu qu'il possédait une relation intrinsèque avec l'adminsitration centrale lusitanienne, ce qui lui fournait, en même temps, une relation avec le roi. Ces agents royaux consacraeint leur confiance dans la structure administrative de la Couronne, tout en reconnaissant l'autorité du roi comme souverain, et, à son tour, ils s'utilisaient du pouvoir politique royal dans le but de monter socialement. Le roi, d'autre part, cherchait, par le biais de ces agens, assurer ses prérogatives en Outre-Mer. Ainsi, une hiérarchie au Portugal d'Outre-Mer a été établie, en formant de grands réseaux gouvernamentaux. Pour cette recherche il a été utilisé comme des sources les faveurs royales, les lectures de diplomés, la documentation produite par les médiateurs et les ordonnances royales dans la période définie. Mots-clés: Empire Portugais d'Outre-Mer ; Mesures administratives ; Médiateurs royaux ; Service de Médiation de Sao Paulo et Paranagua
Políticas administrativas imperiais: o caso da ouvidoria de Paranaguá (1723-1812)
Este artigo apresenta a articulação entre as instituições político-administrativas do Império Ultramarino Português pontuando que inclusive as mais distantes instituições, no caso a Comarca de Paranaguá, estavam também inseridas na lógica governativa da Coroa. Por mais que as dinâmicas especificas da localidade provocassem diferentes ações políticas é certo que a Capitania de São Paulo e a Comarca de Paranaguá também participaram do gradual processo de centralização administrativa promovidos pela monarquia lusa.
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