296 research outputs found

    Lessons of spin and torsion: Reply to ``Consistent coupling to Dirac fields in teleparallelism"

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    In reply to the criticism made by Mielke in the pereceding Comment [Phys. Rev. D69 (2004) 128501] on our recent paper, we once again explicitly demonstrate the inconsistency of the coupling of a Dirac field to gravitation in the teleparallel equivalent of general relativity. Moreover, we stress that the mentioned inconsistency is generic for {\it all} sources with spin and is by no means restricted to the Dirac field. In this sense the SL(4,R)SL(4,R)-covariant generalization of the spinor fields in the teleparallel gravity theory is irrelevant to the inconsistency problem.Comment: Revtex, 4 pages, no figure

    Teleparallel Equivalent of Non-Abelian Kaluza-Klein Theory

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    Based on the equivalence between a gauge theory for the translation group and general relativity, a teleparallel version of the non-abelian Kaluza-Klein theory is constructed. In this theory, only the fiber-space turns out to be higher-dimensional, spacetime being kept always four-dimensional. The resulting model is a gauge theory that unifies, in the Kaluza-Klein sense, gravitational and gauge fields. In contrast to the ordinary Kaluza-Klein models, this theory defines a natural length-scale for the compact sub-manifold of the fiber space, which is shown to be of the order of the Planck length.Comment: Revtex4, 7 pages, no figures, to appear in Phys. Rev.

    Floristic Composition Of A Neotropical Inselberg From EspĂ­rito Santo State, Brazil: An Important Area For Conservation

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    Our study on granitic and gneissic rock outcrops on Pedra dos Pontões in Espírito Santo state contributes to the knowledge of the vascular flora of inselbergs in southeastern Brazil. We registered 211 species distributed among 51 families and 130 genera. Orchidaceae, Bromeliaceae and Polypodiaceae were the most representative families. Concerning vegetative habit, herbs were predominant and about the preference for substrates, holorupicolous species and epiphytes were most speciose. The richest rocky habitat type was woody thicket, with 122 exclusive species. In total, 27 of the species registered in our study are cited on official lists of endangered plant species from Espírito Santo state and Brazil. In addition, two new records of angiosperms for Espírito Santo flora and two new species were recorded for the area. Our data demonstrates the importance of the area for conservation of unique biodiversity that serves as a sanctuary for a rich rupicolous flora composed of endemic and endangered species, some of which are new to science. © 2017 Check List and Authors.13

    Life-cycle greenhouse gas emissions of portuguese olive oil

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    The main goal of this paper was to assess the greenhouse gas (GHG) intensity of olive oil production in Portugal. A life-cycle model and inventory were implemented for the entire production process, including a comprehensive analysis of olive cultivation, olive oil extraction, packaging, and distribution. Data originates from five differently-sized Portuguese olive growers and from a total of six olive oil mills, representing the three extraction processes in use: three-phase extraction, two-phase extraction, and traditional pressing. The results show that the GHG intensity lies in the range 1.8-8.2 kg CO2eq/liter and that the main contributors were fertilizers (production and field emissions). Efficient use of fertilizers thus seems to be a key factor for mitigating the GHG intensity of olive oil production.This research was supported by project ECODEEP (Eco-efficiency and Eco-management in the Agro Industrial sector, FCOMP–05–0128–FEDER–018643) and the Portuguese Scienc

    Valorization of cereal by-products from the milling industry as a source of nutrients and bioactive compounds to boost resource-use efficiency

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    Cereal by-products (wheat germ, maize bran–germ mixture, rye bran, and wheat bran) from the flour milling industry were characterized for their nutritional value and chemical composition, as well as for antioxidant and antibacterial activities. Carbohydrates (including sucrose) were the major nutritional constituents (56.35–78.12 g/100 g dw), followed by proteins (11.2–30.0 g/100 g dw). The higher energy value (432.3 kcal/100 g dw) was presented by the wheat germ. This by-product also presented the highest citric acid content (0.857 g/100 g dw), the most abundant organic acid detected. Unsaturated fatty acids predominated in all samples given the high content of linoleic (53.9–57.1%) and oleic (13.4–29.0%) acids. Wheat germ had the highest levels of tocopherols (22.8 mg/100 g dw) and phenolic compounds (5.7 mg/g extract, with a high apigenin-C-pentoside-C-hexoside content). In turn, while the wheat bran extract was particularly effective in inhibiting the formation of thiobarbituric acid reactive substances (TBARS), the rye bran extract was the only sample capable of protecting erythrocytes from oxidative hemolysis. Regarding antibacterial properties, in general, the lowest minimum inhibitory concentrations were observed against methicillin-resistant Staphylococcus aureus. These results highlight the characterized by-products as sustainable ingredients for the development of novel bakery and functional food products and contribute to a better bioresource-use efficiency and circularity.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support by national funds FCT/MCTES to CIMO (UIDB/00690/2020) and national funding by FCT, P.I., through the institutional scientific employment program-contract for L. Barros, A. Fernandes, M.I. Dias, and C. Pereira and through the individual scientific employment program-contract for J. Pinela (CEECIND/01011/2018) and M. Carocho (CEECIND/00831/2018). To FEDER-Interreg España-Portugal program for financial support through the project TRANSCoLAB 0612_TRANS_CO_LAB_2_P.info:eu-repo/semantics/publishedVersio

    Expansion of activated cxcr5+icos+ tfh cells and plasmablasts induced by seasonal influenza vaccine is impaired in anti-il-6r treated rheumatoid arthritis patients

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    Objectives: To investigate the importance of IL-6 for the in vivo differentiation of human Tfh cells, taking advantage of influenza vaccination in patients under anti-IL-6R therapy.info:eu-repo/semantics/publishedVersio

    Biochemical approaches on commercial strains of Agaricus subrufescens growing under two environmental cultivation conditions

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    In the present work, the effect of the cultivation process, in the field and under a con- trolled environment, on biochemical parameters by using commercial strains of A. subrufescens were evaluated. The results obtained revealed that the strains cultivated in the field presented higher levels for most of the parameters evaluated (organic acids (20.5–48.0 g/100 g dw), tocopherols (107.0–198.6 μg/100 g dw), and phenolic acids and related compounds (245.2–359.0 μg/100 g dw and 10.6–23.7 μg/100 g dw, respectively)), except for the carbohydrates (53.4–72.6 g/100 g dw), energetic value (373–380 Kcal/100 g dw), and total free sugars (28.8–43.1 g/100 g dw), parameters in which the strains grown in a controlled environment present better results. For both cultivation systems, similar results were obtained regarding saturated, monounsaturated, and polyunsaturated fatty acids, as well as antioxidant and antimicrobial activities. These data contribute to the knowledge and highlight the characterized strains and the cultivation process, which can be used to obtain ingredients with potential applicability as a source of functional compounds.This research was funded by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP no. 19/00419-8 and 2018/21492-2). The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES to CIMO (UIDB/00690/2020); national funding by FCT, P.I., through the institutional scientific employment program-contract for A.F., C.P. and L.B. contracts. This work is funded by the European Structural and Investment Funds (FEEI) through the Regional Operational Program North 2020, within the scope of Project Mobilizador ValorNatural®.info:eu-repo/semantics/publishedVersio

    Teleparallel Energy-Momentum Distribution of Spatially Homogeneous Rotating Spacetimes

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    The energy-momentum distribution of spatially homogeneous rotating spacetimes in the context of teleparallel theory of gravity is investigated. For this purpose, we use the teleparallel version of Moller prescription. It is found that the components of energy-momentum density are finite and well-defined but are different from General Relativity. However, the energy-momentum density components become the same in both theories under certain assumptions. We also analyse these quantities for some special solutions of the spatially homogeneous rotating spacetimes.Comment: 12 pages, accepted for publication in Int. J. Theor. Phy

    The stress granule protein G3BP1 alleviates spinocerebellar ataxia-associated deficits

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    Koppenol et al. show that overexpression of G3BP1 in cell models of SCA2 and SCA3 leads to a reduction in ataxin-2 and ataxin-3 aggregation. G3BP1 lentiviral delivery reduces motor deficits and neuropathology in preclinical models, suggesting that G3BP1 may be a potential therapeutic target for polyQ disorders. Polyglutamine diseases are a group of neurodegenerative disorders caused by an abnormal expansion of CAG repeat tracts in the codifying regions of nine, otherwise unrelated, genes. While the protein products of these genes are suggested to play diverse cellular roles, the pathogenic mutant proteins bearing an expanded polyglutamine sequence share a tendency to self-assemble, aggregate and engage in abnormal molecular interactions. Understanding the shared paths that link polyglutamine protein expansion to the nervous system dysfunction and the degeneration that takes place in these disorders is instrumental to the identification of targets for therapeutic intervention. Among polyglutamine diseases, spinocerebellar ataxias (SCAs) share many common aspects, including the fact that they involve dysfunction of the cerebellum, resulting in ataxia. Our work aimed at exploring a putative new therapeutic target for the two forms of SCA with higher worldwide prevalence, SCA type 2 (SCA2) and type 3 (SCA3), which are caused by expanded forms of ataxin-2 (ATXN2) and ataxin-3 (ATXN3), respectively. The pathophysiology of polyglutamine diseases has been described to involve an inability to properly respond to cell stress. We evaluated the ability of GTPase-activating protein-binding protein 1 (G3BP1), an RNA-binding protein involved in RNA metabolism regulation and stress responses, to counteract SCA2 and SCA3 pathology, using both in vitro and in vivo disease models. Our results indicate that G3BP1 overexpression in cell models leads to a reduction of ATXN2 and ATXN3 aggregation, associated with a decrease in protein expression. This protective effect of G3BP1 against polyglutamine protein aggregation was reinforced by the fact that silencing G3bp1 in the mouse brain increases human expanded ATXN2 and ATXN3 aggregation. Moreover, a decrease of G3BP1 levels was detected in cells derived from patients with SCA2 and SCA3, suggesting that G3BP1 function is compromised in the context of these diseases. In lentiviral mouse models of SCA2 and SCA3, G3BP1 overexpression not only decreased protein aggregation but also contributed to the preservation of neuronal cells. Finally, in an SCA3 transgenic mouse model with a severe ataxic phenotype, G3BP1 lentiviral delivery to the cerebellum led to amelioration of several motor behavioural deficits. Overall, our results indicate that a decrease in G3BP1 levels may be a contributing factor to SCA2 and SCA3 pathophysiology, and that administration of this protein through viral vector-mediated delivery may constitute a putative approach to therapy for these diseases, and possibly other polyglutamine disorders.PPBI-POCI-01-0145-FEDER-022122info:eu-repo/semantics/publishedVersio
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