815 research outputs found
O stress nas crianças
O presente documento reflete a experiência vivida ao longo da minha prática pedagógica realizada no âmbito do mestrado em Educação Pré-escolar e Ensino do Primeiro Ciclo do Ensino Básico, na Escola Superior de Educação, Comunicação e Desporto do Instituto Politécnico da Guarda.
Esta praxis foi concretizada em dois contextos escolares diferentes: pré-escolar e 1.º ciclo, onde desempenhei funções de docência, tendo a possibilidade de verificar que aprendizagens as crianças adquiriram, no que concerne ao desenvolvimento de competências.
Para além da introdução e da bibliografia, o trabalho comporta três partes essenciais sob a forma de três capítulos. No capítulo I abordo pormenorizadamente o enquadramento institucional, no capítulo II descrevo o processo de prática de ensino supervisionada e no capítulo III investigo e desenvolvo a temática do stress nas crianças, abordando as suas várias facetas, procurando responder às dúvidas iniciais e analisando com detalhe as suas causas e consequências.
O stress é intrínseco à natureza humana e só deixa de existir depois da morte, sendo um acontecimento existencial com que se tem de aprender a lidar. Os nossos corpos estão preparados para sentir stress e reagir. O stress é a resposta a uma alteração que requer um reajustamento e uma adaptação, sendo possível controlá-lo. A capacidade de o controlar está ligada à capacidade de como escolhemos lidar e responder às situações “stressantes”: a nossa capacidade de resiliência.
A análise dos dados obtidos pelos questionários demonstrou que as crianças sentem stress, apresentando determinados sintomas que são consequência desse fator. Todos possuímos recursos para reagir às mudanças. As causas do stress podem variar de pessoa para pessoa
Social zebrafish: Danio rerio as an emerging model in social neuroendocrinology
The fitness benefits of social life depend on the ability of animals to affiliate with
others and form groups, on dominance hierarchies within groups that determine
resource distribution, and on cognitive capacities for recognition, learning and information transfer. The evolution of these phenotypes is coupled with that of neuroendocrine mechanisms, but the causal link between the two remains underexplored.
Growing evidence from our research group and others demonstrates that the tools
available in zebrafish, Danio rerio, can markedly facilitate progress in this field. Here,
we review this evidence and provide a synthesis of the state-of-the-art in this model
system. We discuss the involvement of generalized motivation and cognitive components, neuroplasticity and functional connectivity across social decision-making brain
areas, and how these are modulated chiefly by the oxytocin-vasopressin neuroendocrine system, but also by reward-pathway monoamine signaling and the effects of
sex-hormones and stress physiology.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio
A cronologia de desenvolvimento do segundo molar e sua relação com a estimativa forense da idade
Introdução: A estimativa da idade insere-se numa área de conhecimento científico que tem vindo a assumir especial importância no âmbito da Medicina Dentária Forense. Apresenta maior relevância em indivíduos vivos e o seu principal objeto de estudo são as crianças, constituindo uma ferramenta chave para o estabelecimento da sua identidade. O estudo da maturação dentária, através de radiografias panorâmicas, constitui um dos métodos mais credíveis para a estimativa da idade. Objetivos: Avaliar a aplicabilidade do método de Demirjian para a estimativa da idade em crianças e investigar a possível correlação entre o estadio de mineralização do dente 3.7 e a idade cronológica da criança, numa amostra populacional da Clínica Dentária da Universidade Católica Portuguesa de Viseu.
Materiais e métodos: Para o efeito, serão examinadas as radiografias panorâmicas de todas as crianças constantes no ficheiro clínico da CDU – Viseu, entre os 5 e os 16 anos de idade. Este estudo foi baseado na escala de pontuações do segundo molar em ambos os sexos, para os diferentes estadios de desenvolvimento dentário, segundo o método de Demirjian. A diferença entre a idade dentária e a idade cronológica foi analisada e comparada através da utilização de modelos de regressão multilinear. Resultados: O desenvolvimento do dente 3.7 assente na metodologia desenvolvida por Demirjian é um indicador válido para prever a idade em crianças e adolescentes da população de Viseu, Portugal. Discussão: Foi possível observar a existência de uma correlação entre a idade estimada e a idade cronológica e ainda que o desenvolvimento dentário, concretamente do segundo molar mandibular, ocorre mais precocemente nas raparigas do que nos rapazes. Estes resultados vão de encontro aos de outros estudos Conclusão: Existe uma associação expressiva entre a idade estimada e os estadios de mineralização atribuídos ao segundo molar permanente inferior, segundo o método de Demirjian.Introduction The age estimation belongs to an area of scientific knowledge that has assumed particular importance in the context of Forensic Dentistry. Presents greater relevance in living individuals and the main object of study are children, since it is a key tool for the establishment of their identity. The study of dental maturation, through panoramic radiographs, is one of the most reliable methods for age estimation.
Objectives: The aim of this study is to evaluate the applicability of Demirjian’s method for age estimation and investigate the possible correlation between the stage of the 3.7 tooth, and the chronological age in a population sample of Viseu, from the Catholic University’s Dental Clinic.
Materials and methods: For this purpose, will be examined, the panoramic radiographs of all children between 5 to16 years of age. This study was based on scale scores of the second molar, in both sexes, for different stages of tooth development, according to Demirjian’s method. The difference between dental age and chronological age will be analyzed and compared by using multilinear regression models.
Results: The development of tooth 3.7, based on the methodology developed by Demirjian, is a valid indicator to predict the age of child and adolescent population of Viseu, Portugal.
Discussion: It was possible to observe the existence of a correlation between the estimated age and chronological age and also the tooth development, specifically the mandibular second molar, that occurs earlier in girls than in boys. These results agree with those of other studies.
Conclusion: There is a significant association between the estimated age and stages of mineralization attributed to the lower second molar, according to Demirjian’s method
Morphometric differences in the grasshopper Cornops aquaticum (Bruner, 1906) from South America and South Africa
The semi-aquatic grasshopper Cornops aquaticum is native to South America and inhabits lowlands from southern Mexico to Central Argentina and Uruguay. It is host-specific to aquatic plants in the genera Eichhornia and Pontederia. A quarantine population has existed in South Africa for 10 y, and it is planned to release it there as a biological control agent of water hyacinth, E. crassipes. Various studies of C. aquaticum are coordinated under HICWA (www.mpil-ploen.mpg.de). This paper compares the morphometry of the release population and 11 native populations in South America. We tested four hypotheses: 1) South African and South American populations of C. aquaticum differ in morphology; 2) the South African laboratory population is more similar to other isolated populations in South America than to nonisolated populations; 3) morphology differs across sites; 4) morphology differs with host plant. South African populations differed from continental nonisolated populations, but not from continental isolated ones. Isolated populations presented smaller individuals than nonisolated, but there was also a change in male morphology: while in nonisolated populations male wing length was similar to their body length, in isolated populations, male wings were smaller than body length. Females were larger when on Eicchornia azurea than on E. crassipes, while males presented larger wings than their body on E. azurea, and similar lengths on E. crassipes. These morphological changes may have resulted from phenotypic plasticity, selection for small size, or because of a loss of genetic diversity in quantitative traits.Fil: Adis, Joachim. Institute for Limnology; AlemaniaFil: Sperber, Carlos F. Universidade Federal de Viçosa; BrasilFil: Brede, Edward G. Institute for Limnology; AlemaniaFil: Capello, Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Franceschini, Maria Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Hill, Martin. Rhodes University; SudáfricaFil: Lhano, Marcos G. Universidade Federal de Viçosa; BrasilFil: Marques, Marinê. A;z M.. Universidade Federal de Mato Grosso; BrasilFil: Nunes, Ana L.. Muséu Paraense Emílio Goeldi; BrasilFil: Polar, Perry. CAB International; Trinidad y Tobag
Isolation of bluish anthocyanin-derived pigments obtained from blueberry surplus using centrifugal partition chromatography
Funding Information: This work was funded by Fundação para a Ciência e Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior (FCT/MCTES, Portugal) through national funds to iNOVA4Health (UIDB/04462/2020 and UIDP/04462/2020), the Associate Laboratory LS4FUTURE (LA/P/0087/2020) and Associated Laboratory for Sustainable Chemistry, Clean Processes, and Technologies LAQV (UIDB/50006/2020 and UIDP/50006/2020). Funding from INTERFACE Programme, through the Innovation, Technology and Circular Economy Fund (FITEC), is gratefully acknowledged. A.N.N. acknowledge FCT for the financial support received through SFRH/BD/144592/2019. J.O. acknowledge FCT her research contract (2022.00042.CEECIND/CP1724/CT0017). The authors also acknowledge Delícias do Tojal, CultiBaga, and Mirtilsul for kindly supplying the biomass. Funding Information: This work was funded by Fundação para a Ciência e Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior (FCT/MCTES, Portugal) through national funds to iNOVA4Health ( UIDB/04462/2020 and UIDP/04462/2020 ), the Associate Laboratory LS4FUTURE ( LA/P/0087/2020 ) and Associated Laboratory for Sustainable Chemistry, Clean Processes, and Technologies LAQV ( UIDB/50006/2020 and UIDP/50006/2020 ). Funding from INTERFACE Programme, through the Innovation, Technology and Circular Economy Fund ( FITEC ), is gratefully acknowledged. A.N.N. acknowledge FCT for the financial support received through SFRH/BD/144592/2019 . J.O. acknowledge FCT her research contract ( 2022.00042.CEECIND/CP1724/CT0017 ). The authors also acknowledge Delícias do Tojal, CultiBaga, and Mirtilsul for kindly supplying the biomass. Publisher Copyright: © 2023 The Author(s)Replacement of synthetic colorants with natural ones is a current marketing trend. Nevertheless, the naturally occurring blue color is rare compared to other colours. In this work, centrifugal partition chromatography (CPC) process was developed as a more efficient and sustainable alternative to reversed phase column chromatography (RP-CC) for the preparative-scale purification of portisins. The strategy began with the extraction of anthocyanins from blueberry surplus and hemi-synthesis of respective portisins. Then, the CPC method development started with the biphasic solvent system selection followed by the optimization of the operating parameters and ended up with a comparison with RP-CC. Aiming at maximizing the portisin content, process throughput, efficiency, and minimizing the environmental risk factor, the effect of sample load (100–500 mg/100 mL of column volume), mobile phase flow rate (10–20 mL/min), and rotation speed (1000–1600 rpm) was evaluated. The two-phase solvent system consisted of tert‑butyl‑methyl ether, n-butanol, acetonitrile, and water (volume ratio 2:2:1:5) acidified with 0.1 vol.% of HCl was selected. The best conditions were 464 mg of sample/100 mL of column volume, 20 mL/min of mobile phase flow rate, and 1600 rpm of rotation speed at reversed phase mode, allowing the purification of portisins by 5-fold. Compared to the RP-CC, the CPC process efficiency was 2.4 times higher, while the CPC process environmental risk factor was 5.5 times lower. Overall, this study suggests that CPC can be considered an effective, and sustainable alternative process for the preparative isolation of portisins. With this purification approach, the blueberry surplus has been valorized and a naturally derived product has been prepared, allowing its subsequent use as a natural blue colorant.publishersversionpublishe
Insights on the laccase extraction and activity in ionic-liquid-based aqueous biphasic systems
Due to their catalytic properties, selectivity, and efficiency, enzymes are excellent biocatalysts. In particular, laccases are versatile multi-copper oxidases with great interest for a wide plethora of biotechnological and environmental applications. Even though several laccase-catalysed processes have been reported at an industrial level, the high costs of their downstream processing required to provide biocatalysts with high purity levels, stability and activity remains one of the main drawbacks when economically evaluating the overall processes. Aqueous biphasic systems based on ionic liquids (ILs) can be foreseen as a promising alternative approach for the extraction and activity maintenance/improvement of enzymes, essentially due to the designer solvents ability of ionic liquids. However, to take advantage of this feature and to use the full potential of IL-based aqueous biphasic systems, it is necessary to understand the effect of ILs as phase-forming constituents and how they affect the enzymes extraction and activity. In order to overcome the lack of information on this topic in the literature, in this work, IL-based aqueous biphasic systems were investigated to extract and enhance the laccase activity, in order to gather evidences that could be used to improve the enzymes downstream processing. To this end, a wide screening of imidazolium-, pyridinium-, pyrrolidinium-, piperidinium-, tetraalkylphosphonium-, and tetraalkylammonium-based ILs as phase-forming components of ABS was carried out. Furthermore, these ILs were used to create ABS combined with salts, polymers and used as adjuvants in polymer-based ABS. Most ABS comprising ILs revealed to be highly efficient extraction platforms, allowing the complete extraction of laccase for all the conditions tested, and with an enzyme activity enhancement by more than 50%. Overall, the obtained results demonstrate that laccase preferentially partitions to the most hydrophilic phase in ABS comprising ILs, both used as adjuvants or as phase-forming components, corresponding to the phase in which the IL is enriched. Furthermore, the IL chemical structure of the IL plays a significant role in the enzyme activity, where ILs with a higher number of hydroxyl groups seem to be relevant to improve the laccase activity.publishe
Aligned carbon nanotube-based sensors for strain monitoring of composites
This paper presents a proof of concept of an aligned carbon nanotube (CNT) based strain sensor tested on the surface of a conventional aeronautic laminate. Two type of strain sensors were produced, type S and type T, in which the CNT alignment was parallel (Y) and transversal (X) to strain direction, respectively. Their electrical resistance response was thoroughly evaluated during cyclic tensile tests. Despite some disparities of the relative electrical resistance behavior in specific strain cycles, probably due to one-off interferences in the CNT conductive mechanism, the obtained gauge factor (GF) values were quite stable. Also, the electrical resistance anisotropy was evaluated and its opposite behavior when the samples were strained in Y- and X-directions may be used as strain direction indicator. Being able to quantify and indicate strain direction with just one 10 x 10 mm CNT patch, this sensor has proven to be suitable for strain sensing applications, namely for structure health monitoring of advanced composites.- Manuscript received March 4, 2021; revised March 25, 2021; accepted March 31, 2021. Date of publication April 5, 2021; date of current version June 30, 2021. This work was supported in part by the Project "Introduction of Advanced Materials Technologies Into New Product Development for the Mobility Industries-IAMAT," under the MIT-Portugal program exclusively financed by Fundacao para a Ciencia e Tecnologia "FCT" under Grant MITP-TB/PFM/0005/2013 and in part by the North Portugal Regional Operational Programme (NORTE 2020) under the Portugal 2020 Partnership Agreements through the European Regional Development Fund (ERDF) Project "Technologies for Sustainable and Smart Innovative Products (TSSiPRO)" under Grant NORTE-01-0145FEDER-000015. The associate editor coordinating the review of this article and approving it for publication was Dr. Cheng-Sheng Huang. (Corresponding author: Ana Raquel Santos.
Exergy efficiency optimization for gas turbine based cogeneration systems
Energy degradation
can be calculated
by
the
quantification
of
entropy and loss
of work
and
is a common approach in
power plant performance analysis. Information about the
location, amount and
sourc
es of system deficiencies are
determined by
the
exergy analysis, which
quantifies the
exergy
destruction.
Micro
-
gas turbines are
prime movers
that are
ideally suited for cogeneration applications due to their
flexibility in providing stable and reliable power. This paper
presents
an
exergy analysis
by means of a
numerical
simulation
of a
regenerative
micro
-
gas turbine
for cogeneration
applications
. The main objective is
to study
the best
configuration of each system component
,
considering the minimization of the
system irreversibilities
. Each component of
the system was evaluated
considering the quantitative exergy
balance
.
Subsequently the optimization
procedure
was applied
to the mathematical model that
describes the
full
system.
The rate of irreversibility, efficiency and flaws are
highlighted for each system component and for
the
whole
system.
The effect
of turbine inlet temperature
change
on plant
exergy destruction
was also evaluated
. The results disclose that
considerable exergy destruction occurs in the combustion
chamber. Also, it
was revealed that the exergy
efficiency is
expressively
dependent on the
changes
of
the turbine inlet
temperature
and increases with
the
latter
.The authors would like to express their acknowledgments for the support given by the Portuguese F01mdation for Science and Technology (FCT) through the PhD grant SFRH/BD/62287/2009. This work was financed by National Funds-Portuguese Foundation for Science and Technology, under Strategic Project and PEst-OE/EME/UI0252/2011 and also the PEst-C/EME/UI4077/2011
Comparison of the effects of different anesthetics on serum haemolysis and glycogenolysis in rats
The anesthetics can differently affect the structure and biological function of tissues and systems. The objective of this study was to compare the effects of three injectable anesthetics generally used in experiments with animals on the degree of haemolysis and glycogenolysis after deep anesthesia. 20 Wistar male rats (330-440g) were used. The animals were divided into three groups: Cloral Hydrate (CH), Ketamine + Xylazine (KX), Zoletil 50® (zolazepam and tiletamina) + Xylazine (ZTX). After deep anesthesia the total blood was collected. Immediately the liver, the white and red gastrocnemius muscles were also withdrawn. The degree of serum haemolysis was quantified by the hemoglobin concentration (g/dL) and the hepatic and muscular glycogen concentration through spectrophotometer analyses. The CH and KX groups presented serum haemolysis (0.49 ± 0.06 g/dL and 0.18 ± 0.06 g/dL, respectively). ZTX group presented no detectable values. The average value of the hepatic and muscular glycogen concentrations exhibited no significant difference between CH and ZTX groups. The data were similar to other studies in the literature. However, the KX induced accentuated glycogenolysis in all tissues. Our data suggest that the anesthetic ZTX seems to be the most appropriate for studies that need simultaneously to quantify the concentration of glycogen and blood markers without interferences. It neither causes glycogenolysis nor haemolysis. ZTX possesses accessible cost, is easily found at veterinary markets, quickly induces deep anesthesia and presents low mortality rate
Carbon nanotubes based multi-directional strain sensor
In this work a new carbon nanotubes (CNT) based multi-directional strain sensor capable of quantifying and indicate strain direction is foreseen. This work investigates the electromechanical behavior of an aligned CNT sensing patch strained at 45◦ in order to validate its multi-directional sensing capability. Vertically aligned CNT forests are produced by chemical vapor deposition (CVD) and then mechanically knocked down onto polyimide (PI) films. Two configurations, diamond (D sample) and square (Sq sample), are considered. The relative electrical resistance (ΔR/R0) and the electrical anisotropy (RB/RA) upon strain increments are analyzed and compared to previous work results (0◦ and 90◦ strain direction). Both 45◦ samples, D and Sq, are sensitive to strain. A correlation between electrical anisotropy behavior and strain direction (0◦, 45◦ and 90◦) is established. The results show that with only an aligned CNT small patch it is possible to quantify and indicate strain in three directions.This work was partially funded under the project “IAMAT – Introduction of advanced materials technologies into new product development for the mobility industries”, with reference MITP-TB/PFM/0005/2013, under the MIT-Portugal program exclusively financed by FCT – Fundação para a Ciência e Tecnologia. This work was also co-financed by national funds through FCT – Fundação para a Ciência e Tecnologia, with the scope of projects with references UIDB/05256/2020 and UIDP/05256/2020”
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