6,399 research outputs found
Superspace Formulation for the BRST Quantization of the Chiral Schwinger Model
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
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
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 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]-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
(--11M--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
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
-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() and
in the reddening law cause very large (1-2 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.
bitstream/item/33361/1/LEVANTAMENTO-E-AVALIACAO.pd
On a Holographic Model for Confinement/Deconfinement
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 to , 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
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 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 transitions: from HOMO to (LUMO+1) () and from (HOMO--1)
to LUMO (). The lowest molecular excitation, which is the 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
larger than 214 nm).Comment: 6 pages, 1 figure, 9 Table
Supercritical fluid technology for agrifood materials processing
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
A Case of Concurrent Riedel's, Hashimoto's and Acute Suppurative Thyroiditis
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
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