12,615 research outputs found

    History of art paintings through the lens of entropy and complexity

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    Art is the ultimate expression of human creativity that is deeply influenced by the philosophy and culture of the corresponding historical epoch. The quantitative analysis of art is therefore essential for better understanding human cultural evolution. Here we present a large-scale quantitative analysis of almost 140 thousand paintings, spanning nearly a millennium of art history. Based on the local spatial patterns in the images of these paintings, we estimate the permutation entropy and the statistical complexity of each painting. These measures map the degree of visual order of artworks into a scale of order-disorder and simplicity-complexity that locally reflects qualitative categories proposed by art historians. The dynamical behavior of these measures reveals a clear temporal evolution of art, marked by transitions that agree with the main historical periods of art. Our research shows that different artistic styles have a distinct average degree of entropy and complexity, thus allowing a hierarchical organization and clustering of styles according to these metrics. We have further verified that the identified groups correspond well with the textual content used to qualitatively describe the styles, and that the employed complexity-entropy measures can be used for an effective classification of artworks.Comment: 10 two-column pages, 5 figures; accepted for publication in PNAS [supplementary information available at http://www.pnas.org/highwire/filestream/824089/field_highwire_adjunct_files/0/pnas.1800083115.sapp.pdf

    Thrombus aspiration in patients with ST-elevation myocardial infarction: results of a national registry of interventional cardiology.

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    BACKGROUND: We aimed to evaluate the impact of thrombus aspiration (TA) during primary percutaneous coronary intervention (P-PCI) in 'real-world' settings. METHODS: We performed a retrospective study, using data from the National Registry of Interventional Cardiology (RNCI 2006-2012, Portugal) with ST-elevation myocardial infarction (STEMI) patients treated with P-PCI. The primary outcome, in-hospital mortality, was analysed through adjusted odds ratio (aOR) and 95% confidence intervals (95%CI). RESULTS: We assessed data for 9458 STEMI patients that undergone P-PCI (35% treated with TA). The risk of in-hospital mortality with TA (aOR 0.93, 95%CI:0.54-1.60) was not significantly decreased. After matching patients through the propensity score, TA reduced significantly the risk of in-hospital mortality (OR 0.58, 95%CI:0.35-0.98; 3500 patients). CONCLUSIONS: The whole cohort data does not support the routine use of TA in P-PCI, but the results of the propensity-score matched cohort suggests that the use of selective TA may improve the short-term risks of STEMI.info:eu-repo/semantics/publishedVersio

    Metal-Insulator Transition in a Disordered Two-Dimensional Electron Gas in GaAs-AlGaAs at zero Magnetic Field

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    A metal-insulator transition in two-dimensional electron gases at B=0 is found in Ga(Al)As heterostructures, where a high density of self-assembled InAs quantum dots is incorporated just 3 nm below the heterointerface. The transition occurs at resistances around h/e^2 and critical carrier densities of 1.2 10^11cm^-2. Effects of electron-electron interactions are expected to be rather weak in our samples, while disorder plays a crucial role.Comment: 4 pages, 3 figures, 21 reference

    A conjugate for the Bargmann representation

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    In the Bargmann representation of quantum mechanics, physical states are mapped into entire functions of a complex variable z*, whereas the creation and annihilation operators a^\hat{a}^\dagger and a^\hat{a} play the role of multiplication and differentiation with respect to z*, respectively. In this paper we propose an alternative representation of quantum states, conjugate to the Bargmann representation, where the roles of a^\hat{a}^\dagger and a^\hat{a} are reversed, much like the roles of the position and momentum operators in their respective representations. We derive expressions for the inner product that maintain the usual notion of distance between states in the Hilbert space. Applications to simple systems and to the calculation of semiclassical propagators are presented.Comment: 15 page

    Exploring bioactive compounds present in international patents targeting brain functions

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    The interest in nervous system disorders is an evident fact with more than 60 000 articles published on PUBMED only in the year of 2016. Actually, in our daily life we are constantly exposed to different environmental factors known to be prejudicial to the health of our nervous system. In this context, a holistic view of food consumption is gaining increasing importance with the perspective of using functional components of specific foods to improve our health or diminish the risk of disease. The aim of our work is to evaluate the use of nutritional food components of traditional Portuguese diet in international patents of dietary supplements or the so called functional foods described to improve brain functions. The WIPO platform was used to collect data of these patents, and from the last 3 years we identified 35 patents using more than 150 different components. We selected the most frequent components and the indications described in the patents, and then examined the possible bioactive compounds for each component. The prevalent functional components described were walnuts, peanuts, wolfberries, mulberries, dates, jujube, creatine, carnitine, ginseng and soybean. Other components rich in omega-3, such as docosahexaenoic acid and superba oil, were also identified. These patents were described to target brain functions such as intelligence, memory, concentration and in some cases compounds are indicated to traumatic brain injury. Regarding local sources, we found several nutritional components of traditional Portuguese diet that have similar compounds of those found in the international components described in patents. We believe this information will help in the valorisation of national products.info:eu-repo/semantics/publishedVersio

    Production, breeding and potential of cowpea crop in Brazil.

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    About 50 years ago cowpea was reported as a relatively minor tropical legume. However, in the last years, it has been emerging as one of the most important food legume of the 21st century (SINGH, 2010). Brazil is not out of this panorama. Brazilian agriculture is undergoing major technological changes and, in addition, globalization in agribusiness has caused impacts on the production chain of several crops, particularly those heavily dependent on the use of a large volume of agricultural inputs, mainly fertilizers and pesticides. Such crops have had a higher production cost each year. On the other hand, this situation has brought new opportunities. Business farmers have sought new alternatives for their production arrangements. In this context cowpea constitutes one of the best options.bitstream/item/85620/1/Doc-216-Production.pd

    Prototype 9.7 m Schwarzschild-Couder telescope for the Cherenkov Telescope Array: status of the optical system

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    The Cherenkov Telescope Array (CTA) is an international project for a next-generation ground-based gamma ray observatory, aiming to improve on the sensitivity of current-generation experiments by an order of magnitude and provide energy coverage from 30 GeV to more than 300 TeV. The 9.7m Schwarzschild-Couder (SC) candidate medium-size telescope for CTA exploits a novel aplanatic two-mirror optical design that provides a large field of view of 8 degrees and substantially improves the off-axis performance giving better angular resolution across all of the field of view with respect to single-mirror telescopes. The realization of the SC optical design implies the challenging production of large aspherical mirrors accompanied by a submillimeter-precision custom alignment system. In this contribution we report on the status of the implementation of the optical system on a prototype 9.7 m SC telescope located at the Fred Lawrence Whipple Observatory in southern Arizona.Comment: Proceedings of the 35th International Cosmic Ray Conference (ICRC 2017), Busan, Korea. All CTA contributions at arXiv:1709.0348
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