701 research outputs found

    Minimal AdS-Lorentz supergravity in three-dimensions

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    The N=1\mathcal{N}=1 AdS-Lorentz superalgebra is studied and its relationship to semigroup expansion developed. Using this mathematical tool, the invariant tensors and Casimir operators are found. In terms of these invariants, a three-dimensionnal Chern--Simons supergravity action with AdS-Lorentz symmetry is constructed. The Killing spinors for a BTZ black-hole like solution of the theory are discussed.Comment: 18 pages, matches published versio

    Biomass partitioning and gas exchange parameters in different Musa cultivars as influenced by natural shade

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    Poster presented at Tropentag 2011 Development on the Margin. Bonn (Germany), 3-7 Oct 2011

    The response of Musa cultivar root systems to a tree shade gradient

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    Poster presented at Tropentag 2011 - Development on the Margin. Bonn (Germany), 3-7 Oct 2011

    Greenhouse Gases Reforming and Hydrogen Upgrading by Using Warm Plasma Technology

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    Global warming is an alarming problem with adverse impact on climate change. Carbon dioxide (CO2) and methane (CH4) have been identified as the most significant greenhouse gases (GHG) normally arising from anthropogenic activities; therefore, promising treatment technologies are developing all over the world to resolve this problem. The warm plasma is an emergent process with low specific energy requirement capable to reach high temperature to produce excited species and support subsequent chemical reactions. Consequently, warm plasma reactors can be accomplished with simple structure reactors having high gas flow rates and treatment capacity. Plasma interaction with GHG leads into a molecular dissociation, mainly forming CO and H2, also known as syngas, which represents an alternative energy source with innovative applications in microturbines and fuel cells, among other emerging applications. The process here explained assures a significant reduction in CO2 emission and H2 yield upgrading. The reforming experimental results by using two warm plasma reactors are connected in series to improve the syngas yield. This alternative represents a great possibility for CO2 conversion

    The uniform bounded deciding property and the separable quotient problem

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    [EN] Saxon-Wilansky's paper "The equivalence of some Banach space problems" contains six properties equivalent to the existence of an infinite dimensional separable quotient in a Banach space with nice simplified proofs. In the frame of uniform bounded deciding property, we prove that for an infinite dimensional Banach space E the following properties are equivalents: 1) The unit sphere of E contains a dense and non uniform bounded deciding subset. 2) The unit sphere S of E contains a dense and non strong norming subset. 3) E admits an infinite dimensional separable quotient.López Alfonso, S.; Moll López, SE. (2019). The uniform bounded deciding property and the separable quotient problem. Revista de la Real Academia de Ciencias Exactas Físicas y Naturales Serie A Matemáticas. 113(2):1223-1230. https://doi.org/10.1007/s13398-018-0543-7S122312301132Argyros, S.A., Dodos, P., Kanellopoulos, V.: Unconditional families in Banach spaces. Math. Ann. 341, 15–38 (2008)Fernández, J., Hui, S., Shapiro, H.: Unimodular functions and uniform boundedness. Publ. Mat. 33, 139–146 (1989)Font, V.P.: On exposed and smooth points of convex bodies in Banach spaces. Bull. London Math. Soc. 28, 51–58 (1996)Ka̧kol, J., López-Pellicer, M.: On Valdivia strong version of Nikodym boundedness property. J. Math. Anal. Appl. 446, 1–17 (2017)López-Alfonso, S., Mas, J., Moll, S.: Nikodym boundedness property and webs in σ\sigma σ -algebras. RACSAM Rev. R. Acad. Cienc. Exactas Fís. Nat. Ser. A Math. 110, 711–722 (2016)López-Alfonso, S.: On Schachermayer and Valdivia results in algebras of Jordan measurable sets. RACSAM Rev. R. Acad. Cienc. Exactas Fís. Nat. Ser. A Math. 110, 799–808 (2016)Nygaard, O.: A strong uniform boundedness principle in Banach spaces. Proc. Am. Math. Soc. 129, 861–863 (2001)Schachermayer, W.: On some classical measure-theoretic theorems for non-sigma-complete Boolean algebras. Dissertationes Math. (Rozprawy Mat.) 214, 33 (1982)Śliwa, W.: The separable quotient problem and the strongly normal sequences. J. Math. Soc. Jpn. 64, 387–397 (2012)Saxon, S.A., Wilansky, A.: The equivalence of some Banach space problems. Colloq. Math. 37, 217–226 (1977)Valdivia, M.: On certain barrelled normed spaces. Ann. Inst. Fourier 29, 39–56 (1979)Valdivia, M.: On Nikodym boundedness property. RACSAM Rev. R. Acad. Cienc. Exactas Fís. Nat. Ser. A Mat. 107, 355–372 (2013

    Tradeoff Analysis of Agri-Food Systems for One CGIAR

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    Učinak praha avokada, suncokretova ulja te različitih omjera voluminozne i koncentrirane krme u obroku na unos hrane, probavljivost hrane i proizvodnost mladih ovnova

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    The objective of this study was to evaluate the inclusion of avocado flour and sunflower oil as energy sources in different proportions, as well as different forage:concentrate ratios on the productive performance and feed intake of male rams, and the in vitro dry matter digestibility, organic matter digestibility and gas production. The intake was measured in diets containing avocado flour or sunflower oil with 60% forage: 40% concentrate, and in diets with different forage:concentrate ratios and 10% inclusion of avocado flour or sunflower oil. The daily weight gain was registered for 84 days, the in vitro dry matter digestibility was determined at 48 h, and the in vitro gas production was evaluated at 72 h. The partial production of gas at 24 hours, raw protein, raw fat, and ash were used to estimate the metabolizable energy and organic matter digestibility. Low levels of avocado flour and sunflower oil in the diet showed the highest intake, in vitro dry matter digestibility and in vitro gas production. Daily weight gains were 0.28 kg in avocado flour and 0.30 kg in sunflower oil diets, both at 10% inclusion and 40% forage: 60% concentrate. The inclusion of high levels of avocado flour or forage in the diet decreased the feed intake of male sheep. The best avocado flour level was 10% with 40% forage: 60% concentrate.Cilj rada bio je istražiti utjecaj različitih omjera između praha avokada i suncokretova ulja kao izvora energije, te različitih omjera između voluminozne i koncentrirane krme u obroku na unos hrane i proizvodnost mladih ovnova. Osim toga, in vitro istražena je probavljivost suhe tvari, probavljivost organske tvari i proizvodnja plina. Unos hrane mjeren je u obrocima koji su sadržavali prah avokada ili suncokretovo ulje uz omjer između voluminozne i koncentrirane krme od 60:40% ili u obrocima sa različitim omjerom voluminozne i koncentrirane krme uz dodatak 10% praha avokada ili suncokretova ulja. Dnevni prirast bilježen je tijekom 84 dana. Probavljivost suhe tvari in vitro određivana je 48 h, a proizvodnja plina in vitro 72 h od uzimanja uzoraka. Za određivanje metaboličke energije i probavljivosti organske tvari korišteni su parcijalna proizvodnja plina 24-ti sat, sirovi protein, sirova mast i pepeo. Niske razine praha avokada i suncokretova ulja u obroku rezultirale su najvišim unosom hrane te najvišom in vitro probavljivošću suhe tvari i in vitro proizvodnjom plina. Dnevni prirast bio je 0,28 kg u životinja kojima je davano 10% praha avokada, 0,30 kg u životinja kojima je davano 10% suncokretova ulja, pri čemu je omjer voluminozne i koncentrirane krme iznosio 40:60%. Dodavanje visokih razina praha avokada ili voluminozne krme u obrok dovelo je do nižeg unosa hrane kod mladih ovnova pa je zaključeno da je najpovoljnija razina dodanog praha avokada 10% uz omjer voluminozne i koncentrirane krme 40:60%

    A study on text-score disagreement in online reviews

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    In this paper, we focus on online reviews and employ artificial intelligence tools, taken from the cognitive computing field, to help understanding the relationships between the textual part of the review and the assigned numerical score. We move from the intuitions that 1) a set of textual reviews expressing different sentiments may feature the same score (and vice-versa); and 2) detecting and analyzing the mismatches between the review content and the actual score may benefit both service providers and consumers, by highlighting specific factors of satisfaction (and dissatisfaction) in texts. To prove the intuitions, we adopt sentiment analysis techniques and we concentrate on hotel reviews, to find polarity mismatches therein. In particular, we first train a text classifier with a set of annotated hotel reviews, taken from the Booking website. Then, we analyze a large dataset, with around 160k hotel reviews collected from Tripadvisor, with the aim of detecting a polarity mismatch, indicating if the textual content of the review is in line, or not, with the associated score. Using well established artificial intelligence techniques and analyzing in depth the reviews featuring a mismatch between the text polarity and the score, we find that -on a scale of five stars- those reviews ranked with middle scores include a mixture of positive and negative aspects. The approach proposed here, beside acting as a polarity detector, provides an effective selection of reviews -on an initial very large dataset- that may allow both consumers and providers to focus directly on the review subset featuring a text/score disagreement, which conveniently convey to the user a summary of positive and negative features of the review target.Comment: This is the accepted version of the paper. The final version will be published in the Journal of Cognitive Computation, available at Springer via http://dx.doi.org/10.1007/s12559-017-9496-

    La Motivación y la Atención-Concentración en Futbolistas. Revisión de Estudios

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    The study of psychological variables leads to understand the relationship between sport performance and the sportsman. This study stress motivation and attention-concentration in the footballer. The aim is to depend the main scientific research on the two psychological skills. It is Review of primary and secondary sources such as articles, dissertations and books are used. The method used is the analysis and review of the literature. Several studies which analysed some of the psychological variables studied in this population are available. In conclusion, we can emphasize that psychological skills sport performance, and that the front and midfielders have a higher motivation than other players.El estudio de las variables psicológicas permite comprender, junto con el análisis de otras variables, la relación entre el rendimiento deportivo y el deportista. En este estudio se incide sobre la motivación y la atención-concentración en el futbolista. El objetivo es profundizar en las principales investigaciones científicas realizadas sobre las dos habilidades psicológicas. Se utiliza la revisión de fuentes primarias y secundarias como son artículos, tesis doctorales y libros. El método utilizado es el análisis y revisión de la literatura. Se encuentran diversos estudios que analizan alguna de las variables psicológicas objeto de estudio en esta población. Como conclusiones se destaca que las habilidades psicológicas influyen en el rendimiento deportivo; y que los delanteros y centrocampistas poseen una motivación más alta que otros jugadores
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