2,127 research outputs found

    Light charged Higgs boson production at the Large Hadron electron Collider

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    We study the production of a light charged Higgs boson at the future Large Hadron electron Collider (LHeC), through the process e−p→νeH−qe^- p \to \nu_e H^- q considering both decay channels H−→bcˉH^- \to b \bar c and H−→τνˉτH^- \to \tau \bar \nu_\tau in the final state. We analyse these processes in the context of the 2-Higgs Doublet Model Type III (2HDM-III) and assess the LHeC sensitivity to such H−H^- signals against a variety of both reducible and irreducible backgrounds. We confirm that prospects for H−H^- detection in the 2HDM-III are excellent assuming standard collider energy and luminosity conditions.Comment: 12 pages, 12 figures. Accepted in Physical Review

    Estimation of genetic parameters and verification of early selection efficiency in baru (Dipteryx alata).

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    This study aimed at verifying the efficiency of early selection, and estimating the genetic parameters in Dipteryx alata. The 66 half-sib families were obtained from three seed provenances at the Brazilian Savannah of the state of Minas Gerais. The experiment was carried out in a randomized block design with 3 replications and 5 plants per plot. Data diameters at breast height (DBH) and total height (TH) were taken at the ages of 64, 125 and 138 months. REML/BLUP methodology was applied in the D. alata different provenances and progenies. Analysis indicated significant genetic variability (P < 0.01) between and within provenances. Both traits, DBH and TH, presented high narrow sense heritability for the ages analyzed. High genetic correlation occurred between DBH and TH traits, and between ages (age-age); thus, it allowed indirect selection, as well as early selection with high genetics gains

    Gravitational wave background from binary systems

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    Basic aspects of the background of gravitational waves and its mathematical characterization are reviewed. The spectral energy density parameter Ω(f)\Omega(f), commonly used as a quantifier of the background, is derived for an ensemble of many identical sources emitting at different times and locations. For such an ensemble, Ω(f)\Omega(f) is generalized to account for the duration of the signals and of the observation, so that one can distinguish the resolvable and unresolvable parts of the background. The unresolvable part, often called confusion noise or stochastic background, is made by signals that cannot be either individually identified or subtracted out of the data. To account for the resolvability of the background, the overlap function is introduced. This function is a generalization of the duty cycle, which has been commonly used in the literature, in some cases leading to incorrect results. The spectra produced by binary systems (stellar binaries and massive black hole binaries) are presented over the frequencies of all existing and planned detectors. A semi-analytical formula for Ω(f)\Omega(f) is derived in the case of stellar binaries (containing white dwarfs, neutron stars or stellar-mass black holes). Besides a realistic expectation of the level of background, upper and lower limits are given, to account for the uncertainties in some astrophysical parameters such as binary coalescence rates. One interesting result concerns all current and planned ground-based detectors (including the Einstein Telescope). In their frequency range, the background of binaries is resolvable and only sporadically present. In other words, there is no stochastic background of binaries for ground-based detectors.Comment: 30 pages, 16 figure

    Tourist-hotel relationship: the role of customer experience and brand authenticity

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    The demand for authenticity has been growing in the contemporary world and in consumers´ lives (Fine, 2003; Grayson and Martinec, 2004). According to Grayson and Martinec (2014), the quest for authenticity has existed for many years. However, today it is reflected in the purchase of several market offerings. In a time of intense competition, it is difficult for companies to differentiate their products (goods or services) and authenticity can, indeed, act as an important element of differentiation (Gilmore and Pine, 2007). Despite the relevance of the term, research about authenticity has been very fragmented and different definitions can be found in the literature (Beverland and Farrelly, 2010; Grayson ands Martinec, 2004). In any case, some level of agreement can be identified as authenticity is many times associated with being genuine, real and/or true (Beverland and Farrelly, 2010). When the concept is applied to objects like, for instance, brands, the notion of brand authenticity emerges (Fritz, Schoenmueller, and Bruhn, 2017).info:eu-repo/semantics/publishedVersio

    Insights into brand authenticity and customer engagement in a restaurant setting: A text mining approach

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    The aim of this study is to analyze the dimensions of customer engagement, brand authenticity and other related constructs (need for uniqueness and brand love) in customers’ online reviews through text-mining and sentiment analysis trends. This study focuses on Yelp.com comments and use a random sample of 3,877 reviews of restaurants, in ten cities in the USA. A customer engagement and authenticity dictionaries are created, based on previously validated scales and extended using WordNet 2.1. Findings reveal that cognitive processing is the strongest dimension of consumer engagement. Results further indicate that brand love presents lower polarity value compared to brand authenticity, which means that consumer tend to value more the perception of authenticity than the love relationship with the brand to become more engaged.info:eu-repo/semantics/submittedVersio

    Atopic Eczema/Dermatitis Syndrome in Portugal – Sensitization Pattern

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    A dermatite atópica é uma doença inflamatória crónica da pele, tendo por base diversos mecanismos etiopatogénicos. Considerando a sua heterogeneidade, foi, recentemente, introduzida outra designação para esta patologia - Síndroma Eczema / Dermatite Atópica (SEDA). A associação com alergia alimentar ou respiratória parece ser variável entre as diferentes populações. Objectivo: Analisar um grupo de doentes referenciados à Consulta de Imunoalergologia com o diagnóstico de SEDA, com o intuito de avaliar a associação desta síndrome com a alergia alimentar e doença respiratória nesta população. Métodos: Do número total de primeiras consultas do nosso Serviço durante os anos 2000-01 (n = 3436) foram seleccionados todos os doentes com história de SEDA. A população foi analisada quanto a idade, sexo, existência de alergia alimentar, doença respiratória e resultados de testes cutâneos (TC) por picada. Resultados: Foram encontrados 193 doentes com uma idade média de 7,5 anos de idade (1 -54 anos) e relação F/M = 1 / 1,5. Eram 68 (35,8%) os doentes com SEDA isolada. SEDA associada a doença respiratória foi identificada em 113 (58,5%) e a alergia alimentar em 19 (9,8%) - na maioria dos casos manifestando-se por urticária / angioedema. Os TC revelaram-se positivos para aeroalergénios em 74% e para alergénios alimentares em 18% da amostra. Os TC foram positivos em 58,9% dos doentes com SEDA isolada, 84,2% dos doentes com alergia alimentar e 92% com doença respiratória. Conclusão: Em contraste com outras séries, foi encontrada uma baixa prevalência de alergia alimentar, na maioria dos casos manifestada por reacções imediatas. Mais de metade dos doentes estudados apresentava doença respiratória alérgica associada a uma elevada prevalência de sensibilização a aeroalergénios. Estes resultados reflectem a heterogeneidade das populações com SEDA e a importância dos aeroalergénios na nossa população

    Regulatory Cells

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    O papel das células T reguladoras na indução e manutenção da tolerância periférica tem recebido uma atenção crescente nos últimos anos. Foram descritos vários subgrupos de células T reguladoras, com base em marcadores de superfície e na produção de citocinas, não havendo no entanto marcadores específicos para nenhum destes subgrupos, pelo que a sua classificação se baseia no seu mecanismo de supressão. Desconhece-se qual dos subgrupos de células T reguladoras terá papel preponderante na prevenção e controlo das doenças alérgicas, sendo no entanto consensual a sua importância para a homeostasia
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