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Experimental modal analysis of a synthetic composite femur
No full textIn this paper we describe the experimental characterization of the modal parameters of a synthetic composite femur model widely used in biomechanical research studies. The objective of the experimental procedure was to identify the natural frequencies and mode shapes of an unconstrained (free-free) femur. The experimental data were compared with the same obtained in an analog study performed with a fresh cadaveric femur bone. Other objective of the study was to investigate modal analysis as a technique to validate a finite element model of a composite femur with isotropic material properties
Large scale morphodynamics characterisation of exposed sandy beaches by DGPS
No full textDuring the last decades important stretches of the coastal foredunes in the Aveiro Lagoon exposed sandy beaches (Portuguese west coast) were destroyed by wave action, with strong impact on the local social activities. As the foredune erosion and degree of destruction by overwashes are related with the foreshore and backshore morphology, the study of the morphological evolution of these areas of the beach is of special interest. In the present work, time scale of volumetric changes and recovery periods are analysed. A sector located south of an groin field with two contrasting stretches was selected. In one of those stretches, with about 3 kin extension, artificial sand remobilization from the foreshore was operated to build a sand dike. The second one with 4 km extension has evolved without any direct human intervention. In order to determine the morphological evolution of these two stretches, a regular monitoring program was performed by accurate DGPS measurements provided by a multi-antenna system adapted on a four wheel motor quad. Cross correlation analysis between morphological data obtained from DGPS measurements of the exposed beach and wave parameters was done. The wave breaking parameters were computed with the use of a wave model which includes shoaling and refraction. The average beach volume and the average beach face slope were correlated with the average wave height in the breaking zone for several different periods, since the day before to each survey until three months prior to each survey. From the results obtained we conclude that, the recovery period of the sedimentary volumes in the stretch where sand was artificially removed is lower than in the stretch without any human intervention, although this conclusion does not apply for beach face slope recovery
Surface modification of graphene nanosheets with gold nanoparticles: the role of oxygen moieties at graphene surface on gold nucleation and growth
No full textGraphene sheets, which possess unique nanostructure and a variety of fascinating properties, are considered as promising nanoscale building blocks of new nanocomposites, namely as a support material for the dispersion of metal nanoparticles. One of the methodologies used to prepare graphene sheets is the chemical exfoliation of graphite in aqueous medium, which produces oxygen functionalized graphene sheets. Here, we show that the presence of oxygen functionalities at the graphene surface provides reactive sites for the nucleation and growth of gold nanoparticles. Gold nanoparticles are effectively grown at functionalized graphene surfaces using a simple chemical method in aqueous medium. The nucleation and growth mechanism depends on the degree of oxygen functionalization at the graphene surface sheets, no gold nanoparticles are obtained at totally reduced graphene surfaces. Additionally, our studies indicate that the graphene/gold nanocomposites are potential substrates for SERS (surface enhanced Raman scattering) in particular for single gold nanoparticle SERS studies
Corpo, auto-eficácia e capacidade laboral: na senda do bem-estar docente
Get PDFDoutoramento em Ciências da EducaçãoA nova concepção de Educação reveste-se de um grau de exigência cada vez
maior. Mais do que nunca, torna-se fundamental diversificar estudos na busca
de novos conhecimentos e estratégias que promovam o bem-estar docente.
(Re)pensar a Educação é também pensar naqueles que a ajudam a dar forma
e a tornam exequível – os educadores e professores.
Este estudo tem como objectivo identificar a importância da relação do Corpo e
da Imagem Corporal com a Actividade Docente, com a Auto-Eficácia Docente
e com a Capacidade para o Trabalho e suas implicações no bem-estar
docente.
A amostra foi constituída por um total de 703 docentes dos vários níveis de
ensino, pertencentes a jardins-de-infância, escolas e instituições do ensino
superior de todo o país. Para recolha de dados foram utilizados, como
instrumentos de avaliação, um questionário sobre o Corpo, Imagem Corporal e
Actividade Docente - CICAD (Castelo-Branco & Pereira, 2000) cuja finalidade
foi verificar a importância e a relação do corpo e da imagem corporal na
actividade docente, uma escala sobre a Auto-Eficácia Docente (Schwarzer,
Schimitz & Daytner, 1999) para percepção da auto-eficácia dos educadores e
professores e um Índice de Capacidade para o Trabalho – ICT, desenvolvido
pelo Finnish Institute of Occupational Health e traduzido e adaptado, para a
população portuguesa e países de língua oficial portuguesa, por Silva e
colaboradores (2000) cujo propósito foi verificar a capacidade para o trabalho
dos educadores e professores.
Os resultados obtidos evidenciam que o corpo e a imagem corporal se
relacionam com a actividade docente e o bem-estar, que os educadores e
professores revelam, tendencialmente, uma elevada auto-eficácia e que, de
acordo com os valores internacionalmente padronizados, 3,3% da amostra
apresenta um ICT Baixo, 28,7% um ICT Moderado, 47,6% um ICT Bom e
16,8% um ICT Óptimo.
Neste sentido propomos a inclusão nos Cursos de Formação de Professores,
de conteúdos que valorizem e aprofundem a expressividade do corpo na
docência e que dotem os educadores e professores de estratégias e
competências que promovam a sua auto-eficácia e a sua capacidade laboral.
As principais limitações do trabalho associam-se à inexistência de estudos
específicos que relacionem o corpo e a imagem corporal com a actividade
docente e restantes conceitos, o que dificultou a análise comparativa.
Sugerimos a realização de mais investigações no domínio das temáticas
desenvolvidas.The new concept of Education has had an increasingly higher level of demand.
More than ever, it is crucial to diversify studies, in the quest for new knowledge
and teacher well-being promoting strategies. (Re)Thinking Education is also
thinking of those who help to shape it and to make it feasible – educators and
teachers.
This study intends to identify the importance of the relation of the Body and the
Body-Image with Teaching Activity, with Teacher Self-Efficacy and with
Working Ability and their implications in Teachers’ well-being.
The sample consists of more than 703 teachers belonging to the several
teaching levels: from kindergartens, schools and higher education institutions
from the whole country (Portugal).
Data collection was made resorting to assessment instruments, namely a
questionnaire on Body, Body-Image and Educational Activity CICAD (Castelo-
Branco & Pereira, 2002), whose purpose was to verify the importance and the
relationship of body and body-image in teaching activity; it was also used a
scale on Teachers’ Self-Efficacy (Schwarzer, Schmitz & Daytner, 1999), in
order to verify the perception of educators’ and teachers’ self-efficacy; the last
instrument that was used was the Work Ability Index (WAI), developed by The
Finnish Institute of Occupational Health that was translated and adapted for the
Portuguese population and Portuguese speaking countries, by Silva and
collaborators (2000), with the purpose of verifying the ability to work among
educators and teachers.
The obtained results indicate that body and body-image are related to teaching
activity and well-being in teaching. It shows also that educators and teachers
display a tendency towards high self-efficacy. According to the international
standard, 3,3% of our sample presents a Poor ICT; 28,7% a Moderated ICT;
47,6% a Good ICT; and 16,8% present an Optimal ICT.
Therefore, the inclusion of contents in training courses for teachers, such as
those that value and deepen body expression in teaching and provide
educators and teachers with strategies and skills that enhance their selfefficacy
and working ability is encouraged.
The main limitations of this study concern the inexistence of specific studies
that relate body and body-image with the teaching activity and further related
concepts, which made comparative analysis rather difficult.
Further investigation within the mentioned areas is strongly suggested.POCTI/ESP/40743/200
Comparative study between the toxicity of 3,4-dichloroaniline and sodium-bromide with 21-days chronic test and using lactate-dehydrogenase activity of Daphnia magna Straus
No full textWe studied the effect of 3,4-dichloroaniline (DCA) and sodium bromide (NaBr) on the lactate dehydrogenase (LDH) activity in homogenate of Daphnia magna Straus cultured during 21 days in the presence of several concentrations of each chemical. The activity of LDH increased at concentrations of 10 mug/l of DCA and 19 mg/l of NaBr. These concentrations correspond to LOEC values obtained in 21-day chronic tests with Daphnia magna, which suggests that LDH activity may be used as a faster indicator of toxicity in tests with D. magna.STRDA/C/CEN/566/92JNICTFEDERSTRIDE Progra
Ecological effects of the herbicide linuron in tropical freshwater microcosms
No full textEffects of a single application of the photosynthesis-inhibiting herbicide linuron (0, 15, 50, 150, and 500 mu g/L) on the ecology of outdoor plankton-dominated microcosms were studied in Thailand. As a result of the decreased photosynthesis, DO and pH decreased while EC, alkalinity and nutrient concentrations increased. Chlorophytes belonging to the genera Scenedesmus, Coelastrum and Pediastrum were the most sensitive taxa, whereas several other chlorophytes, diatoms, and cryptophytes increased in abundance. Tolerant taxa appeared to be less digestable for several zooplankton taxa, which subsequently decreased in abundances. Chamaesiphon sp. (Cyanobacteria) was the most susceptible periphyton species. As a consequence of functional redundancy, effects of the herbicide on the chlorophyll-a content of periphyton and especially phytoplankton did not always reflect the effects noted on community level. (C) 2008 Elsevier Inc. All rights reserved
Can multiscale traffic analysis be used to differentiate Internet applications
No full textAn accurate mapping of Internet traffic to applications can be important for a broad range of network management and measurement tasks, including traffic engineering, service differentiation, performance/failure monitoring and security. Traditional mapping approaches have become increasingly inaccurate because many applications use nondefault or ephemeral port numbers, use well-known port numbers associated with other applications, change application signatures or use traffic encryption. In this paper we will demonstrate that multiscale traffic analysis based on multi-order wavelet spectrum can be used as a discriminator of Internet applications traffic profiles. By performing clustering analysis over the multiscale wavelet spectrum coefficients that are inferred from the measured traffic, the proposed methodology is able to efficiently differentiate different IP applications without using any payload information. This characteristic will allow the differentiation of traffic flows in unencrypted and encrypted scenarios. In order to compare the differentiating potential of different traffic application data, upload, download and joint upload and download flow statistics are considered to evaluate the identification approach for each selected protocol. Moreover, we also evaluate which timescales and spectrum orders are more relevant for the traffic differentiation. From the analysis of the obtained results we can conclude that the proposed methodology is able to achieve good identification results using asmall set of timescales of a single order wavelet spectrum of a general raw traffic statistic. © 2010 Springer Science+Business Media, LLC
Synthesis, characterisation and magnetic properties of cobalt (II) complexes with 3-hydroxypicolinic acid (HpicOH): [Co(picOH)2(H2O)(2)] and mer-[N(CH3)(4)][Co(picOH)(3)] . H2O
No full textTwo complexes with Co2+ and 3-hydroxypicolinic acid, [Co(picOH)2(H2O)2] (I) and mer-[N(CH3)4][Co(picOH)3] Æ H2O (II), have
been synthesised and characterised using single-crystal X-ray diffraction, elemental analysis, infrared spectroscopy, and thermoanalytical
measurements. The 3-hydroxypicolinate ligands are coordinated to the Co2+ centres via its typical N,O-chelating coordination
fashion. While in I the presence of two coordinated water molecules leads to the formation of a neutral [Co(picOH)2(H2O)2]
complex which is strongly hydrogen bonded to another four neighbouring complexes, in II the inclusion of a third picOH ligand
leads to an anionic octahedral complex, [Co(picOH)3] , in which all the N- and O-atoms are occupying mer positions. The properties
of these two compounds were further investigated by measuring their magnetic behaviour
Morphological micro-patterning of tubular-windows on crystalline K2V3O8 sheets
No full textSingle crystals of K2V3O8 have been synthesized using a mild hydrothermal method. The synthetic method allows
morphological micro-patterning of well aligned tubular-windows on sheet-like K2V3O8 singlecrystals. Thelate ral
dimensions of the tubular-windows range from 2 to 0.1 mm and areca. 80 mm in depth
Lanthanopolyoxotungstoborates: synthesis, characterization, and layer-by-layer assembly of europium photoluminescent nanostructured films
No full textNew lanthanopolyoxotungstoborates, K6 xHx[Ln(BW11O39)(H2O)3] nH2O, Ln(III) Sm, Eu, Tb, Er,
were prepared and characterized by spectroscopic methods (Fourier transform infrared, Fourier
transform-Raman, 11B solid-state nuclear magnetic resonance, and photoluminescence) and elemental
analysis. A layer-by-layer assembly method was employed to fabricate multilayered films
containing the europium heteropolyanion and the polyelectrolytes poly(sodium 4-styrenesulfonate)
and poly(diallydimethylammonium chloride). The photoluminescence behavior of these final nanostructures
was in