6,345 research outputs found

    Superspace Formulation for the BRST Quantization of the Chiral Schwinger Model

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    It has recently been shown that the Field Antifield quantization of anomalous irreducible gauge theories with closed algebra can be represented in a BRST superspace where the quantum action at one loop order, including the Wess Zumino term, and the anomalies show up as components of the same superfield. We show here how the Chiral Schwinger model can be represented in this formulation.Comment: 11 pages, Late

    Edible films and coatings based on agrifood residues: A new trend in the food packaging research

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    Food packaging trends have been changing in the last years, mainly due to consumer concerns about plastic pollution and agrifood waste. Recent advances in the development of edible films and coatings are discussed. These systems can be much more than packaging, with additional functions such as antioxidant, antimicrobial, and nutritional properties, among others. Challenges in industrial processes and/or in some films’ properties are addressed from the authors’ point of view. The use of agrifood residues in these packaging systems is included as a promising strategy that promotes sustainability and circular economy. The authors consider that more research and actions are needed to achieve the best packaging material for each food product with reduced production costs.info:eu-repo/semantics/publishedVersio

    Weak Galactic Halo--Fornax dSph Connection from RR Lyrae Stars

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    For the first time accurate pulsation properties of the ancient variable stars of the Fornax dwarf spheroidal galaxy (dSph) are discussed in the broad context of galaxy formation and evolution. Homogeneous multi-band BVIBVI optical photometry of spanning {\it twenty} years has allowed us to identify and characterize more than 1400 RR Lyrae stars (RRLs) in this galaxy. Roughly 70\% are new discoveries. We investigate the period-amplitude distribution and find that Fornax shows a lack of High Amplitude (A_V\gsim0.75 mag) Short Period fundamental-mode RRLs (P\lsim0.48 d, HASPs). These objects occur in stellar populations more metal-rich than [Fe/H]\sim-1.5 and they are common in the Galactic halo (Halo) and in globulars. This evidence suggests that old (age older than 10 Gyr) Fornax stars are relatively metal-poor. A detailed statistical analysis of the role of the present-day Fornax dSph in reproducing the Halo period distribution shows that it can account for only a few to 20\% of the Halo when combined with RRLs in massive dwarf galaxies (Sagittarius dSph, Large Magellanic Cloud). This finding indicates that Fornax-like systems played a minor role in building up the Halo when compared with massive dwarfs. We also discuss the occurrence of HASPs in connection with the luminosity and the early chemical composition of nearby dwarf galaxies. We find that, independently of their individual star formation histories, bright (M_V\lsim-13.5 mag) galaxies have HASPs, whereas faint ones (M_V\gsim-11 mag) do not. Interestingly enough, Fornax belongs to a luminosity range (--11<<MV<_V<--13.5 mag) in which the occurrence of HASPs appears to be correlated with the early star formation and chemical enrichment of the host galaxy.Comment: 7 pages, 5 figures, A&A, accepte

    New type II Cepheids from VVV data towards the Galactic center

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    The Galactic center (GC) is the densest region of the Milky Way. Variability surveys towards the GC potentially provide the largest number of variable stars per square degree within the Galaxy. However, high stellar density is also a drawback due to blending. Moreover, the GC is affected by extreme reddening, therefore near infrared observations are needed. We plan to detect new variable stars towards the GC, focusing on type II Cepheids (T2Cs) which have the advantage of being brighter than RR Lyrae stars. We perform parallel Lomb-Scargle and Generalized Lomb-Scargle periodogram analysis of the KsK_s-band time series of the VISTA variables in the Via Lactea survey, to detect periodicities. We employ statistical parameters to clean our sample. We take account of periods, light amplitudes, distances, and proper motions to provide a classification of the candidate variables. We detected 1,019 periodic variable stars, of which 164 are T2Cs, 210 are Miras and 3 are classical Cepheids. We also found the first anomalous Cepheid in this region. We compare their photometric properties with overlapping catalogs and discuss their properties on the color-magnitude and Bailey diagrams. We present the most extensive catalog of T2Cs in the GC region to date. Offsets in E(JKsJ-K_s) and in the reddening law cause very large (\sim1-2 kpc) uncertainties on distances in this region. We provide a catalog which will be the starting point for future spectroscopic surveys in the innermost regions of the Galaxy.Comment: A&A, accepte

    Levantamento e avaliacao da qualidade de sementes de algodao, Gossypium hirsutum L. distribuidas aos agricultores de alguns Estados do nordeste do Brasil.

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    On a Holographic Model for Confinement/Deconfinement

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    We study the thermodynamics of the hard wall model, which consists in the introduction of an infrared cut-off in asymptotically AdS spaces. This is a toy model for confining backgrounds in the context of the gauge/gravity correspondence. We use holographic renormalization and reproduce the existence of a Hawking Page phase transition recently discussed by Herzog. We also show that the entropy jumps from N0N^0 to N2N^2, which reinforces the interpretation of this transition as the gravity dual of confinement/deconfinement. We also show that similar results hold for the phenomenologically motivated soft wall model, underlining the potential universality of our analysis.Comment: 14 pages. V2: We included a new section discussing the soft wall model and new references. V3: We clarified some points and updated the references. Results unchanged. Version published in PR

    Theoretical study of molecular electronic excitations and optical transitions of C60

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    We report results on ab initio calculations of excited states of the fullerene molecule by using configuration interaction (CI) approach with singly excited determinants (SCI). We have used both the experimental geometry and the one optimized by the density functional method and worked with basis sets at the cc-pVTZ and aug-cc-pVTZ level. Contrary to the early SCI semiempirical calculations, we find that two lowest 1T1u1Ag^1 T_{1u} \leftarrow {}^1 A_g electron optical lines are situated at relatively high energies of ~5.8 eV (214 nm) and ~6.3 eV (197 nm). These two lines originate from two 1T1u1Ag^1 T_{1u} \leftarrow {}^1 A_g transitions: from HOMO to (LUMO+1) (6hu3t1g6h_u \to 3t_{1g}) and from (HOMO--1) to LUMO (10hg7t1u10h_g \to 7t_{1u}). The lowest molecular excitation, which is the 13T2g1 ^3 T_{2g} level, is found at ~2.5 eV. Inclusion of doubly excited determinants (SDCI) leads only to minor corrections to this picture. We discuss possible assignment of absorption bands at energies smaller than 5.8 eV (or λ\lambda larger than 214 nm).Comment: 6 pages, 1 figure, 9 Table

    A Case of Concurrent Riedel's, Hashimoto's and Acute Suppurative Thyroiditis

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    Riedel's thyroiditis (RT) is a rare form of infiltrative and inflammatory disease of the thyroid, first described by Bernard Riedel in 1896. The concurrent presence of RT and other thyroid diseases has been reported, but, the association of RT with Hashimoto's thyroiditis and acute thyroiditis has not yet been reported. We present a case of concurrent Riedel's, Hashimoto's and acute thyroiditis that occurred in a 45-year-old patient

    Supercritical fluid technology for agrifood materials processing

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    This work was financially supported by Fundação para a Ciência e Tecnologia (FCT), Portugal, through the project Strategic Project UIDB/00102/2020 and Programmatic Project UIDP/00102/2020 of the Chemical Process Engineering and Forest Products Research Centre (CIEPQPF), and UI/05704/2020 of ciTechCare. M. C. Gaspar acknowledges FCT for the financial support through the Scientific Employment Stimulus – Individual and Institutional Calls (CEECIND/00527/2017 and CEECINST/00060/2021). The authors participate in the CYTED network RESALVALOR — Valorización de Residuos de la Industria Agroalimentaria. The authors are also grateful for the work of the designer José Gomes in the preparation of Figures 1 and 2.Supercritical fluid technology has been applied in the food area for processing and preserving food products and/or monitoring the food quality, with known advantages. The main solvent used at supercritical conditions for food applications is carbon dioxide. Some examples are presented, from the traditional decaffeination of coffee up to the micronization of vanilla, passing through innovative processes such as the extrusion of protein-based snacks and drying of beetroot. The gap between research and industries is addressed, mainly due to a lack of data about food chemical changes that may occur during some processes, as well as technical data. However, this is an area in clear expansion and probably, in the future, we will have a menu composed of meals prepared by supercritical methods.info:eu-repo/semantics/publishedVersio
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