279 research outputs found

    Thermostatistics of deformed bosons and fermions

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    Based on the q-deformed oscillator algebra, we study the behavior of the mean occupation number and its analogies with intermediate statistics and we obtain an expression in terms of an infinite continued fraction, thus clarifying successive approximations. In this framework, we study the thermostatistics of q-deformed bosons and fermions and show that thermodynamics can be built on the formalism of q-calculus. The entire structure of thermodynamics is preserved if ordinary derivatives are replaced by the use of an appropriate Jackson derivative and q-integral. Moreover, we derive the most important thermodynamic functions and we study the q-boson and q-fermion ideal gas in the thermodynamic limit.Comment: 14 pages, 2 figure

    Revisiting the role of soccer spectator's behavioral intentions and its antecedents

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    Football is one of the most rooted sports worldwide attracting millions of spectators, but clubs face an increasing competition of other leisure activities. Understanding how to increase spectators' behavioral intentions towards their favorite football teams is paramount for sport managers, given that a behavioral intention represents a measure of how much a person is willing to engage in a specific behavior. Thus, the purposes of this study were (1) to explain the role of spectators' behavioral intentions, and (2) to highlight its antecedents within the football context. In doing so, this study starts by providing a review of consumption-related aspects that have been associated with football spectators' behavioral intentions, such as emotions experienced during the games, service quality, team brand associations and satisfaction. Subsequently, the main findings from previous studies conducted with football spectators are highlighted and managerial implications are suggested in order to aid football clubs at providing good overall consumption experiences to their spectators, and thus contributing to increase attendance levels. Finally, future research avenues are suggested in order to expand our understanding on how to strengthen the link between football spectators and their teams, with subsequent associated benefits.Publisher Statement: Open-Access License: This is an open access article licensed under the terms of the Creative Commons Attribution-Non-Commercial 4.0 International Public License (CC BY-NC 4.0) (https://creativecommons.org/licenses/by-nc/4.0/legalcode), which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited

    Carcass characteristics and meat quality of lambs fed high levels of spineless cactus in the diet

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    The objective was to evaluate the effect of increasing the dietary inclusion of spineless cactus (Nopalea cochenillifera Salm Dyck) on the carcass characteristics and meat quality of confined lambs. Thirty-two male Santa Inês lambs with an average age of 140 days and an initial body weight of 20.4 ± 2.60 kg were used in this study. The lambs were housed in individual stalls for 70 days and individually fed a ration with spineless cactus included at 0, 241, 519, or 753 g/kg of dry matter (DM). The lambs were slaughtered, and characteristics of the carcass and meat were recorded and analysed. Inclusion of spineless cactus had a quadratic effect on the bodyweight at slaughter and on the empty bodyweight of the lambs. The inclusion of 500 g/kg of spineless cactus provided the highest predicted cold carcass weight (16.03 kg). There was a quadratic effect of the inclusion of spineless cactus on the weight of meat cuts and leg composition of lambs. The inclusion of spineless cactus did not influence pH, tenderness, and water-retention capacity of the meat. However, the intramuscular fat content increased 1 mg for every 10 g/kg inclusion of spineless cactus in the diet. Quadratic effects were observed of the inclusion of spineless cactus on the weights of the liver, heart, rumen, blood, skin and internal fat of the lambs. Up to 500 g/kg of spineless cactus could be included in the diet of confined lambs

    A case study on surplus mushrooms production: extraction and recovery of vitamin D

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    The presented case study illustrates the possibility of adding value to the biological surplus remaining from the mushroom cultivation industry. In essence, the unused mushroom parts were submitted to UV-C irradiation, with the purpose of increasing the vitamin D2 content and validat-ing its extraction. Vitamin D2 concentration in three different mushroom species (Agaricus bisporus, A. bisporus Portobello, and Pleurotus ostreatus) was obtained by high-performance liquid chromatogra-phy (HPLC), by means of an ultraviolet (UV) detector. The method was validated using an A. bisporus Portobello sample, and its reproducibility and accuracy were confirmed. Independently of the UV-C irradiation dose, the effect on vitamin D2 concentration was significant, allowing it to increase from less than 4 µg/g dry weight (dw) to more than 100 µg/g dw in all mushroom species. These results are good indicators of the feasibility of industrial surplus mushrooms as sustainable vitamin D2 food sources, besides contributing to strengthen the circularity principals associated to the mushroom production chain.The authors are grateful to the Foundation for Science and Technology (Fundação para a Ciência e Tecnologia, Lisboa, Portugal) for financial support by national funds FCT/MCTES to CIMO (UIDB/00690/2020), and R.V.C.C.’s PhD grant (SFRH/BD/137436/2018). The authors are also grateful to “Ponto Agricola” for providing the mushroom materials. A.F., J.C.M.B. and L.B. also thank the national funding by FCT, P.I. through the institutional scientific employment program contract. This work is funded by the ERDF through the Regional Operational Program North 2020, within the scope of Project Mobilizador Norte-01-0247-FEDER-024479: ValorNatural®.info:eu-repo/semantics/publishedVersio

    Flame retardants: Polybrominated diphenyl ethers

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    Para melhorar a qualidade de vida do Homem foram desenvolvidos durante as últimas décadas muitos produtos químicos, como por exemplo os retardantes de chama. Estes compostos são adicionados a uma grande variedade de materiais cuja finalidade é evitar ou retardar a propagação de incêndios.Os éteres difenílicos polibromados (PBDEs, Polybrominated Diphenyl Ethers) pertencem ao grupo de retardantes de chama bromados. Estes compostos são misturados com os polímeros e tendem a libertarem-se por acção do tempo, do calor e da luz para o meio ambiente. Os PBDEs são compostos lipofílicos e são classificados como poluentes orgânicos persistentes (POPs, Persistent Organic Pollutants) por serem persistentes, tóxicos e bioacumuláveis. Por serem POPs, os PBDEs ganharam relevo nos estudos efetuados em diversas matrizes ambientais e no Homem (fluidos fsisiológicos, tecidos, órgãos), com o objetivo de estudar e identificar a sua ocorrência, assim como, evitar a sua dispersão.Este artigo tem como objetivo abordar o problema dos retardantes de chama, mais concretamente dos PBDEs, no que se refere à sua utilização, propriedades físico-químicas, toxicidade e ocorrência no meio ambiente, dando enfase aos estudos e problemas em Portugal. To improve the quality of life of people have been developed during the last decades many chemicals such as flame retardants. These compounds are added to a wide variety of materials whose purpose is to prevent or slow the spread of fire.Polybrominated diphenyl ethers (PBDEs) belong to the group of brominated flame retardants. These compounds are blended with polymers and tend to free themselves by weathering, heat and light to the environment. PBDEs are lipophilic compounds and are classified as persistent organic pollutants (POPs) to be persistent, bioaccumulative and toxic. As belonging to the class of POPs, PBDE gained importance in the studies on various environmental matrices and in humans (physiological fluids, tissues, organs) in order to study and identify their occurrence, as well as to prevent its spread.This article aims to address the problem of flame retardants, in particular of PBDE in relation to its use, physico-chemical properties, toxicity and incidence on the environment, and studies focusing on the problems in Portugal
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