4,133 research outputs found
Correlating the interstellar magnetic field with protostellar jets and its sources
This article combines new CCD polarimetric data with previous information
about protostellar objects in a search for correlations involving the
interstellar magnetic field. Specifically, we carried out an optical
polarimetric study of a sample of 28 fields of 10 X 10 arcmin^2 located in the
neighborhood of protostellar jets and randomly spread over the Galaxy. The
polarimetry of a large number of field stars is used to estimate both the
average and dispersion of the interstellar magnetic field (ISMF) direction in
each region. The results of the applied statistical tests are as follows.
Concerning the alignment between the jet direction and the interstellar
magnetic field, the whole sample does not show alignment. There is, however, a
statistically significant alignment for objects of Classes 0 and I. Regarding
the interstellar magnetic field dispersion, our sample presents values slightly
larger for regions containing T Tauri objects than for those harboring younger
protostars. Moreover the ISMF dispersion in regions containing high-mass
objects tends to be larger than in those including only low-mass protostars. In
our sample, the mean interstellar polarization as a function of the average
interstellar extinction in a region reaches a maximum value around 3% for A(V)
= 5, after which it decreases. Our data also show a clear correlation of the
mean value of the interstellar polarization with the dispersion of the
interstellar magnetic field: the larger the dispersion, the smaller the
polarization. Based on a comparison of our and previous results, we suggest
that the dispersion in regions forming stars is larger than in quiescent
regions.Comment: ApJ accepte
Applicability of low macrobending loss hollow-core PCF to FTTH applications
Fiber-To-The-Home (FTTH) technology has been significantly implemented in access networks, providing very high data rates transmission and a variety of digital content to subscribers. It involves an optical cable link being installed between the building entry point and each subscriber with the Multiple Dwelling Units (MDUs), i.e. flats and apartments. In other words, optical cable has to lie fairly straight to carry a strong signal, since typically is necessary to bend, twist and turn the lines in and out of tight corners without degrading the link connection. In this paper we propose the use of Hollow-Core Photonic Crystal Fiber (HC-PCF) for FTTH applications. It is presented an experimental analysis of the macrobending effects in a HC-PCF based on a comparison with traditional fibers and by following the ITU-T G.657B standard recommendations. We observe this fiber, with only 6.5 µm core, is bending loss insensitive, even at extremely small bending radius of 2 mm, in which it presents a loss of only 0.58 dB.251258Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de NÃvel Superior (CAPES
Desigualdades sociais e medidas de ação afirmativa: entre avanços, resistências, incompreensões e novos desafios
A igualdade, diversidade e inclusão social tornaram-se objetivos das sociedades ocidentais, promovidos e reivindicados por várias organizações e coletivos da
sociedade civil, corroborados por estudos académicos e formalizados por diversas
convenções e legislações. No entanto, as desigualdades persistem e as ideologias
dominantes têm permanecido relativamente bem instaladas, contribuindo para
a manutenção de sistemas estruturais de opressão, como o sexismo, o racismo, o
classismo, a homofobia, o capacitismo, entre outros. Nestes termos, em diferentes
contextos e regiões geográficas, os grupos denominados como minorias sociais
têm-se organizado e desenvolvido ações polÃticas importantes que são contempladas nos debates sobre polÃticas públicas, quaisquer que sejam elas, desde que
comprometidas com as suas exigências e trajetórias singulares. Estas reivindicações colocam a tónica na dimensão redistributiva (Fraser 2006) e de reconhecimento identitário (Phillips 2009), a fim de consolidar uma noção de justiça social
(Fraser 2013).info:eu-repo/semantics/publishedVersio
Development and characterization of an active chitosan-based film containing quercetin
This work aims at developing an active chitosan film through the incorporation of quercetin and the evaluation of physical and functional properties of the films made thereof. The addition of quercetin showed to influence films properties in terms of surface morphology, tensile strength, and opacity while elongation-at-break, thickness, water vapor, and oxygen permeability were not significantly affected with incorporation of quercetin. The color parameters of chitosan films were affected by quercetin incorporation with a decrease of the values of L* and a*. The film exhibited a high free-radical scavenging activity, showing antioxidant activity. The film-forming solutions of chitosan with or without quercetin showed antibacterial activity against four Gram-negative and three Gram-positive bacteria. These results showed that quercetin incorporation in chitosan-based films has potential to be used as a solution for active food packaging.Author Marthyna Pessoa de Souza thanks the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES/PDEE-Brazil) and Fundacao de Amparo a Ciencia e Tecnologia do Estado de Pernambuco (FACEPE, Brazil) for fellowships. Miguel A. Cerqueira and Helder D. Silva (SFRH/BPD/72753/2010 and SFRH/BD/81288/2011, respectively) are recipients of a fellowship from the Fundacao para a Ciencia e Tecnologia (FCT, POPH-QREN and FSE Portugal). This research was financially supported by research grants and fellowships from the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), as well as the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) and Fundacao de Amparo a Ciencia e Tecnologia do Estado de Pernambuco (FACEPE). The authors also thank the FCT Strategic Project of UID/BIO/04469/2013 unit, the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462), and the project "BioInd - Biotechnology and Bioengineering for improved Industrial and Agro-Food processes," REF. NORTE-07-0124-FEDER-000028 Co-funded by the Programa Operacional Regional do Norte (ON. 2-O Novo Norte), QREN, FEDE
Electrochemically gated graphene field-effect transistor for extracellular cell signal recording
This work presents an experimental characterization of electrochemically gated graphene field-effect transistors (EGFETs) to measure extracellular cell signals. The performance of the EGFETs was evaluated using cardiomyocytes cells. Extracellular signals with a peak value of 0.4 pico-amperes (pA) embedded in a noise level of 0.1 pA were recorded. Signals in current mode were compared with signals recorded as a voltage. Signals below 28 μV of magnitude can be detected in a noise floor of 7 μV with a signal-to-noise ratio of 4
Hybrid Method Based on NARX models and Machine Learning for Pattern Recognition
This work presents a novel technique that integrates the methodologies of
machine learning and system identification to solve multiclass problems. Such
an approach allows to extract and select sets of representative features with
reduced dimensionality, as well as predicts categorical outputs. The efficiency
of the method was tested by running case studies investigated in machine
learning, obtaining better absolute results when compared with classical
classification algorithms.Comment: In English. SBAI 2021 - Brazilian Symposium on Intelligent Automation
(SBAI - Simposio Brasileiro de Automacao Inteligente). 6 pages. 4 figure
A new continuous distribution on the unit interval applied to modelling the points ratio of football teams
We introduce a new flexible distribution to deal with variables on the unit interval based on a transformation of the sinh–arcsinh distribution, which accommodates different degrees of skewness and kurtosis and becomes an interesting alternative to model this type of data. We also include this new distribution into the generalised additive models for location, scale and shape (GAMLSS) framework in order to develop and fit its regression model. For different parameter settings, some simulations are performed to investigate the behaviour of the estimators. The potentiality of the new regression model is illustrated by means of a real dataset related to the points rate of football teams at the end of a championship from the four most important leagues in the world: Barclays Premier League (England), Bundesliga (Germany), Serie A (Italy) and BBVA league (Spain) during three seasons (2011–2012, 2012–2013 and 2013–2014)
The use of ionic liquids in the processing of chitosan/silk hydrogels for biomedical applications
Natural polymers are adequate renewable resources for the processability of well-defined architectures for
several applications. Combinations of polysaccharides and proteins may mimic the naturally occurring
environment of certain tissues. The main goal of this work renders the application of green chemistry
principles, namely the use of ionic liquids (ILs) and biorenewable sources, such as chitosan (CHT) and
silkfibroin (SF), to process new hydrogel-based constructs. Although the solubilization of both materials
in ILs has been studied individually, this work reports, for the first time, the role of ILs as solvent, for the
production of hydrogels from blends of chitosan and silkfibroin (CSF). These systems offer the
advantage of being homogeneous and presenting easy and short dissolution time of both
biomacromolecules. Moreover, the use of chitosan obtained fromα- andβ-chitin allowed the production
of blended hydrogels with distinct physical–chemical properties.In vitroassays demonstrated that these
hydrogels supported the adhesion and growth of primary human dermalfibroblasts. Taken these
properties together, the CSF hydrogels might be promising biomaterials to be explored for skin tissue
engineering approaches.Fundação para a Ciência e a Tecnologia FCT - SFRH/BPD/45307/2008, SFRH/BPD/
34704/2007, SFRH/BD/64601/2009, PTDC/QUI/68804/2006FEDER - POCTEP 0330_IBEROMARE_1_P
BeefTrader (part II): optimal economical endpoint identification using nonparametric bootstrapping technique decreases greenhouse gases emission and other pollutants in feedlots.
The current study is the second from three sequential abstracts based on BeefTrader DSS to maximize profitability of farmers and the meat industry.Coordenador: Roberto Giolo de Almeida. II SIGEE
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