2,113 research outputs found

    Network construction of non-Abelian chiral spin liquids

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    We use a network of chiral junctions to construct a family of topological chiral spin liquids in two spatial dimensions. The chiral spin liquid phase harbors SU(2)k_k anyons, which stem from the underlying SU(2)k_k WZW models that describe the constituent spin chains of the network. The network exhibits quantized spin and thermal Hall conductances. We illustrate our construction by inspecting the topological properties of the SU(2)2_2 model. We find that this model has emergent Ising anyons, with spinons acting as vortex excitations that bind Majorana zero modes. We also show that the ground state of this network is threefold degenerate on the torus, asserting its non-Abelian character. Our results shed new light on the stability of non-Abelian topological phases in artificial quantum materials

    The Stellar Parameters and Evolutionary State of the Primary in the d'-Symbiotic System StH\alpha190

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    We report on a high-resolution, spectroscopic stellar parameter and abundance analysis of a d' symbiotic star: the yellow component of StH\alpha190. This star has recently been discovered, and confirmed here, to be a rapidly rotating (vsini=100 km/s) subgiant, or giant, that exhibits radial-velocity variations of probably at least 40 km/s, indicating the presence of a companion (a white dwarf star). It is found that the cool stellar component has Teff=5300K and log g=3.0. The iron and calcium abundances are close to solar, however, barium is overabundant, relative to Fe and Ca, by about +0.5 dex. The barium enhancement reflects mass-transfer of s-process enriched material when the current white dwarf was an asymptotic giant branch (AGB) star. The past and future evolution of this binary system depends critically on its current orbital period, which is not yet known. Concerted and frequent radial-velocity measurements are needed to provide crucial physical constraints to this d' symbiotic system.Comment: 9 pages, 1 table, 3 figures. In press to Astrophysical Journal Letter

    Supply Chain Trust: A Two-Way Street?

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    This research compares differences between customers´ and suppliers´ perceptions of the trustworthiness of their supply chain exchange partners and the implications for performance, applying the organizational behavior and marketing literature on trust to the supply chain context. A survey in the logistics sector in Brazil was used to collect data from two independent samples (customers and suppliers). Three alternative models of the antecedents of trustworthiness perceptions and the relationship between trust and performance were tested using multiple regression. This was followed by a panel session with logistics industry experts to discuss the results and their practical implications. We found that the ability of an exchange partner is important to both suppliers and customers in their perceptions of trustworthiness. In addition, customer integrity is important to suppliers, while supplier benevolence is important to customers. Trust is related to expectations about order accuracy, quality and cost by both suppliers and customers and to suppliers’ on-time delivery expectations. The findings support the contention of social exchange theory that, when there is a trusting relationship between exchange partners, there is heightened commitment to jointly held goals. They also support transaction cost economics theory by showing how trust forms an intangible transaction- specific asset that serves as a governance mechanism against opportunistic behavior. The findings provide a useful guideline for managers seeking to improve trust in their supply chain relationships. This paper extends interorganizational trust models showing that the relationship between trust and performance may not be applicable to customers and suppliers in the same manner

    Fluorine Abundances in the Globular Cluster M 4

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    We present chemical abundances for the elements carbon, sodium, and fluorine in 15 red giants of the globular cluster M 4, as well as six red giants of the globular cluster ω\omega Centauri. The chemical abundances were calculated in LTE via spectral synthesis. The spectra analyzed are high-resolution spectra obtained in the near-infrared region around λ\lambda2.3μ\mum with the Phoenix spectrograph on the 8.1m Gemini South Telescope, the IGRINS spectrograph on the McDonald Observatory 2.7m Telescope, and the CRIRES spectrograph on the ESO 8.2m Very Large Telescope. The results indicate a significant reduction in the fluorine abundances when compared to previous values from the literature for M 4 and ω\omega Centauri, due to a downward revision in the excitation potentials of the HF(1-0) R9 line used in the analysis. The fluorine abundances obtained for the M 4 red giants are found to be anti-correlated with those of Na, following the typical pattern of abundance variations seen in globular clusters between distinct stellar populations. In M 4, as the Na abundance increases by ∼\sim+0.4 dex, the F abundance decreases by ∼\sim-0.2 dex. A comparison with abundance predictions from two sets of stellar evolution models finds that the models predict somewhat less F depletion (∼\sim-0.1 dex) for the same increase of +0.4 dex in Na

    Familism and youth : notes about working with young people in socio-education.

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    O artigo objetiva refletir sobre a contradit?ria rela??o entre: Estado, pol?tica socioeducativa voltada para jovens entre 18 e 21 anos e fam?lia. Trata-se de reflex?o constru?da a partir da sistematiza??o da pr?tica profissional e cotejada pela revis?o de literatura. Destacam-se os limites do Estado brasileiro e as estrat?gias familistas voltadas a esse p?blico. Por fim, conclui-se que as perspectivas que acolhem o p?blico de jovens entre dezoito a vinte e um anos, sem fam?lia e cumpridores de medida socioeducativa se afunilam em um processo de descartabilidade humana: ora pela aus?ncia de um elo familiar, ora pela inefic?cia da a??o estatal.The article reflects on the contradictory relationship between the state socio-educational policy, aimed at young people between 18 and 21 years, and the family. It is based on a systematization of professional practice and a comparative literature review. The limits of the Brazilian State and the family strategy aimed at the public stand out. Finally, it concludes that the intended audience, young people between the ages of eighteen and twenty-one, without a family, and who are complying with socio-educational measures, become funneled into situations in which they become disposable, sometimes due to the lack of a family bonds and sometimes due to ineffectiveness of state action

    Systematics of the Neotropical genus Loxozus (Diptera: Neriidae), with notes on distribution and sexual dimorphism

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    The monotypic genus Loxozus Enderlein, 1922 is redescribed. After examining the holotypes of Tetanocera cornuta Walker, 1853 and Loxozus clavicornis Enderlein, 1922, we confirm that these species are synonyms and reiterate that the correct name of the nominal species is Loxozus cornutus (Walker, 1853). The male of L. cornutus is described for the first time and notes on the species’ sexual dimorphism and illustrations of the genitalia are provided, together with distribution data, including new records for Venezuela, Brazil and Peru

    Computational and Complex Network Modeling for Analysis of Sprinter Athletes’ Performance in Track Field Tests

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    The article of record as published may be located at https://doi.org/10.3389/fphys.2018.00843Sports and exercise today are popular for both amateurs and athletes. However, we continue to seek the best ways to analyze best athlete performances and develop specific tools that may help scientists and people in general to analyze athletic achievement. Standard statistics and cause-and-effect research, when applied in isolation, typically do not answer most scientific questions. The human body is a complex holistic system exchanging data during activities, as has been shown in the emerging field of network physiology. However, the literature lacks studies regarding sports performance, running, exercise, and more specifically, sprinter athletes analyzed mathematically through complex network modeling. Here, we propose complex models to jointly analyze distinct tests and variables from track sprinter athletes in an untargeted manner. Through complex propositions, we have incorporated mathematical and computational modeling to analyze anthropometric, biomechanics, and physiological interactions in running exercise conditions. Exercise testing associated with complex network and mathematical outputs make it possible to identify which responses may be critical during running. The physiological basis, aerobic, and biomechanics variables together may play a crucial role in performance. Coaches, trainers, and runners can focus on improving specific outputs that together help toward individuals’ goals. Moreover, our type of analysis can inspire the study and analysis of other complex sport scenarios

    Cultivation of algae in photobioreator and obtention of biodiesel

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    In this work we described the cultivation of Chlorella vulgaris in a photobioreactor to algal biomass production. The dried biomass was used as feedstock for biodiesel production, it presented 26% lipids and via sonocatalysis stage of the methodology resulted in 60% of fatty acid methyl esters (FAME). The FAME content was confirmed by Gas Chromatography (GC).CNPqFAPERGSCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

    Morte súbita e angina vasoespástica

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    Variant angina is defined by chest pain occurring at rest associated with transitory ST segment elevation on ECG, and is caused by a spasm of a coronary artery. Frequently, variant angina is associated with atherosclerotic coronary obstruction and patients with normal coronary arteries are rare. Patients with variant angina and normal coronary arteries have good prognosis, and the development of ventricular arrhythmias or sudden death is rare. The authors present two cases of sudden cardiac death in patients with variant angina and normal coronary arteries
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