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Norm Estimates and Uncertainty Principles Associated with the Laguerre Integral Transform
No full textIn this paper we present some results concerning the action of the Laguerre
integral transform over the class of polynomials and over the class of infinitely differentiable
functions. We prove several uncertainty inequalities of Heisenberg-type,
and we also indicate an explicit boundedness for two classes of generalized Laguerre
integral transforms which include the classical Riemann Liouville fractional integral
Os caminhos do empréstimo: a influência do francês no vocabulário dos emigrantes portugueses
No full textDoutoramento em Linguística PortuguesaResumos indisponívei
Geophysical Study of Fervença Region (Cantanhede-Centre of Portugal)
No full textDoutoramento em GeofísicaA região de Fervença do ponto de vista hidrogeológico é caracterizada por dois
aquíferos, um poroso e mais superficial instalado em formação Quaternárias e
Cretácicas e outro, por ventura, mais profundo instalado em formações
carbonatadas Jurássicas, conhecido pelo “Aquífero karstico da Bairrada”.
Contudo, pouco se sabe sobre a espessura dos terrenos de cobertura e da
estrutura das formações carbonatadas o presente trabalho pretende contribuir
para o esclarecimento destas questões utilizando os métodos geofísicos de
prospecção. É usado um procedimento integrado abarcando sondagens
eléctricas, sísmica de refracção e recorrendo aos dados de sondagens
mecânicas existentes na região.
Tendo sido utilizado o dispositivo Wenner tripotencial desenvolveu-se um
conjunto de material de interpretação, sobre alguns modelos bidimensionais
simples, envolvendo pseudosecções de resistividade alfa e pseudosecções de
quociente entre as resistividades beta e gama para ser utilizado na interpretação
dos dados de campo quer presentes quer em outros trabalhos futuros.
Finalmente a integração dos dados permite propor um modelo estrutural para a
região e avaliar a espessura dos terrenos de cobertura, objectivos centrais do
trabalho.
Aband Cretaceous formations, and the other, eventually deeper, installed in Jurassic
carbonate formations, known as the Bairrada Karstic System.
Although of strategic importance of these aquifers for local water supply and for
agriculture use, there are not comprehensive studies and information about the
thickness of the overlaying formations and the structure of the carbonate
formations.
The present research aims of clarifying these questions using geophysical
prospecting methods. An integrated approach is used including apparent
resistivity soundings, seismic refraction profiles and the available boreholes
information in the region.
A set of interpretation material was developed for simple 2D models and thus
pseudosections for alpha resistivity and for the ratio beta/gamma resistivities
using Wenner tripotential measurements are presented, in order to be used for
the interpretation of the present and future field data.
Finally the integration of all data suggests a structural model for the region and an
evaluation of the thickness of the overlaying layers
Effectiveness of the interventions in preventing the progression of pre-frailty and frailty in older adults: a systematic review protocol
No full textThe objective of this review is to identify the effectiveness of the interventions in preventing progression of pre-frailty and frailty in older adults. More specifically, the review questions are:
- What is the effectiveness of interventions in preventing or reducing frailty in older adults? - How does effectiveness vary with degree of frailty?
- Are there factors that influence the effectiveness of interventions? - What is the economic feasibility of interventions for pre-frailty and frailty
Diferenciação curricular: concepções e práticas de professores
No full textMestrado em Gestão Curricular na especialidade de Matemática, Ciências e Tecnologia EducativaO presente trabalho propõe-se analisar as concepções e práticas curriculares
de professores de Matemática e Ciências da Natureza do 2º Ciclo do Ensino
Básico relativamente ao conceito de diferenciação curricular. O trabalho é
composto por um enquadramento que pretende situar o estudo no campo
conceptual do currículo e da diferenciação curricular e por um estudo empírico
concretizado através da realização de um estudo multi-caso numa escola
integrada desde 1996, no Projecto de Gestão Flexível do Currículo, e que
esteve integrada num Território Educativo de Intervenção Prioritária.
Pretende-se conhecer e perceber através da entrevista semi-estruturada as
concepções dos professores e através da observação directa as suas práticas
curriculares em torno do conceito de diferenciação curricular.
Este conceito operacionaliza-se aqui, no plano teórico e fundamentado na
literatura da área, como um processo de regulação individualizada, que tendo
em conta as características que os alunos apresentam, estrutura modos de
seleccionar métodos e estratégias adequadas à forma como cada aluno é
capaz de aprender.
Foi possível chegar a algumas conclusões, que mostraram que o conceito é
associado, em dois dos casos, predominantemente à compe nsação e ao
apoio individualizado, parecendo dois dos sujeitos acreditar que a
diferenciação encerra na sua raiz mais recôndita aspectos relacionados com a
discriminação. Proporcionar actividades diferentes, solici tar trabalhos de casa
distintos, prestar uma maior atenção a alguns al unos, são exemplos de
práticas que parecem, para estes dois sujeitos, encerrar em si o conceito de
discriminação. Analisaram-se concepções e práticas de desenvolvimento
profissional que se situam no paradigma de racionalidade técnica, percebeuse
que o trabalho desenvolvido na escola se centra numa lógica disciplinar e
individualista, existindo a elaboração de Projectos Curriculares pela
obrigatoriedade do acto e não por uma necessidade sentida. As práticas e as
concepções, nestes dois casos, distanciam-se bastante da concepção de
diferenciação curricular que aqui se assume no plano teórico, porque estão
muito presentes nas suas representações conceitos de uniformidade e
homogeneidade.
Uma outra dimensão da apropriação do conceito que emerge do estudo, a
partir do outro caso estudado, parece contemplar a diferenci ação curricular
como ligada a mecanismos de promoção de mobilidade entre níveis e de
tratamento afectivo de alunos, como o estimular alunos a atingirem diferentes
etapas de aprendizagem conforme as suas necessidades e interesses.
Analisaram-se concepções de desenvolvimento profissional que se situam no
paradigma pedagógico e humanista social, percebeu-se que o trabalho
colaborativo é fomentado, no entanto, considerado muito difícil pelas
condições organizacionais que a escola apresenta. As práticas e as
concepções, neste caso, são reveladoras de alguns contributos pessoais
diferenciadores que a professora estabelece de forma casual em função das
necessidades que os alunos apresentam. As práticas e concepções estão
neste caso mais próximas de conceitos de diferenciação associadas
sobretudo a atitudes de abertura, compreensão e preocupação que cada
professor estabelece com a formação e realização pessoal dos seus alunos.
Em forma de síntese, podemos concluir que em dois dos casos analisaram-se
concepções e práticas muito semelhantes de diferenciação curricular
estritamente relacionadas com conceitos de uniformidade, compensação,
apoio individualizado e discriminação, bastante distantes da concepção de
diferenciação curricular aqui assumida. Num outro caso estudado percebeuse
que o sujeito por centrar nas suas prioridades a aprendizagem dos alunos,
revelou no seu desempenho profissional uma atenção personalizada ao aluno
e uma gestão curricular mais flexível.It is the purpose of this paper to analise the curriculum conceptions and
practices of Maths and Natural Ciences teachers in level two of Basic
Education in terms of the concept of curriculum differentiation.
The work develops a framework which is an attempt at focusing research on
the conceptual field of the curriculum and of curriculum differentiation, and an
empirical study - multi -case one- conducted at a school which has been
indegrated in the Project of Flexible Management Curriculum since 1996, as a
member of a Priority Intervention Educational Territory.
Its objective is to know and understand the teachers conceptions, using a
semi-structured interview and their curriculum practices concerning the
concept of curriculum differentiation through direct observation.
It was possible to get to true conclusions. They have shown that the concept is
predominantly associated, in two or three cases, whith compensation and
individualised support, two or three subjects appearing to believe that
differentiation contains in its deepest origin aspects related with discrimination.
Offering different activities, demanding homework tasks paying a greater
attention to some students are examples of practices which appear to contain,
for these two subjects, the concept of discrimination.
The conceptions and practices of professional development, in terms of the
paradigm of technical rationality, were analysed, and it was understood that
the work developed at school is centred on a subject - matter and
individualised logic, the design of curriculum projects existing because of their
mandatory character and not as a really felt need.
The practices and the conceptions, in these two cases, are quite far from the
concepts of curriculum differentition taken here in the theoretical plan, as
concepts of uniformiliy and homogeneity are strongly present in their
representations.
Another dimension of concepts appropriation which emerges from the
research, with its basis on the other case studied, appears to contemplate
curriculum differentiation as being connected with mechanisms of mobility
promotion among levels and of affective treatment of the students, such as
stimulating them to get to different stages of learning according to these needs
and interests.
The conceptions of professional development within the pedagogical, social
and humanist paradigm were analysed. It was understood that collaborative
work is enhanced. Although it was considered to be very difficult to achieve it,
owing to the organizational conditions of the school. In these circunstances,
the practices and the conceptions bring to the fore some personal contribution
establised by the teacher on a case-to-case basis, according to the students
needs.
In terms of synthesis, we can conclude that in two of the cases quite similar
conceptions and practices of curriculum differentation strictly related with
concepts of uniformily, compensation, individualised support and
discrimination were analysed, quite distant from the conception of curriculum
differentation assumed here. In another case we concluded that the subject
who focused his prioritier on student learning has revealed a personalised
attention on the student and a more flexible curriculum management in his
professional activity
Optical digital to analog conversion performance analysis for indoor set-up conditions
No full textIn visible light communication (VLC) the optical digital to analog conversion (ODAC) approach was proposed as a
suitable driving technique able to overcome light-emitting diode’s (LED) non-linear characteristic. This concept is
analogous to an electrical digital-to-analog converter (EDAC). In other words, digital bits are binary weighted to
represent an analog signal. The method supports elementary on–off based modulations able to exploit the essence
of LED’s non-linear characteristic allowing simultaneous lighting and communication. In the ODAC concept the
reconstruction error does not simply rely upon the converter bit depth as in case of EDAC. It rather depends on
communication system set-up and geometrical relation between emitter and receiver as well. The paper describes
simulation results presenting the ODAC’s error performance taking into account: the optical channel, the LED’s
half power angle (HPA) and the receiver field of view (FOV). The set-up under consideration examines indoor
conditions for a square room with 4mlength and 3mheight, operating with one dominant wavelength (blue) and
having walls with a reflection coefficient of 0.8. The achieved results reveal that reconstruction error increases
for higher data rates as a result of interference due to multipath propagation
Thermal Analysis of high power LEDs using different PCB materials
No full textVisible Light Communication is an emerging
technology in Optical Wireless Communication where the Light Emitting Diodes (LEDs) are utilized for transmission of data. The
luminance of the LEDs increases with the forward current;
however, for high current levels the heat generated by nonradiative
recombination of carriers increases the LED junction
temperature, decreasing the efficiency and the lifetime of the
devices. Therefore, the design of high power LED driver circuits
needs to take into account the unavoidable local heating
produced by high power components. In this paper, we
performed thermal analysis of an LED driver mounted on
Printed Circuit Boards (PCBs) using Thermal Risk Management
(TRM) software and studied the heat dissipated by various
components on PCBs composed of different dielectric materials
such as FR4 and Diamond. Based on TRM simulations, the
replacement of FR4 with diamond caused the junction
temperature to decrease from 64°C to 45.2°C for a forward
current level of 350 mA. The replacement of FR4 with diamond
thus effectively improves the thermal management of LEDs and
corresponding driver circuits
PBL Methodology: enhancing science and mother tongue integration
No full textCurricular integration in school usually departs from a theme that reveals potential to interrelate
knowledge from different disciplinary areas. However, an integrated approach can also be achieved by
following a certain didactic line, problem situation or activity. In this study, a Problem Based Learning
(PBL) methodology was implemented with the intention of promoting better learning in the fields of
Science and Mother Tongue (Portuguese). This methodology has been used at different levels of
schooling, especially related with Science learning, and our aim was to verify its potential to the
improvement of expository text production. The participants were 44 pupils from the 4th grade of a
primary state school, aged between 8-9 years old, divided into two groups (the experimental one and
the control one). To achieve the established aim, three activities related to topics of the science
syllabus were designed in accordance with PBL principles, that are: a) to present a problem that is
relevant in a real context; b) to frame it using a real or a fictional scenario that can motivate pupils c) to
give data sources to help its resolution; d) to promote collaborative work; e) to help pupils dealing with
the proposed data sources through a tutorial process; f) to ask for a final product in which the answer
to the problem is included; g) to assess all the learning process, presenting new situations that imply
the knowledge acquired. The study took place during three months and the written productions of
pupils were assessed with the help of grids for learning verification of scientific concepts and
internalization of the key dimensions associated with written text production. The control group had a
traditional approach of the contents of both disciplines. The results were particularly encouraging in
the experimental group in terms of the presented aims, and reveled that the use of PBL can help
learning in the two subject areas involved. It was also verified that the use of PBL activities had an
impact on communication skills of pupils as well as in their motivation for learning
Why a Logbook? A backpack journey as a metaphor for product design education
No full textRecent literature suggests that the development of cognitive skills should constitute explicit learning objectives in design education. The work describes an educational intervention designed with the intention of promoting the creative and critical thinking performance of a group of Portuguese design students. To this end, creativity and critical thinking tests, pre and post intervention, were applied to the experimental group and to a control group. The intervention was based on two fundamental theoretical assumptions: (1) students’ thinking skills can be promoted by the introduction of Design Thinking as a learning content, and (2) this work should be complemented by the promotion of students’ metacognitive reflection. Comparing the learning process, by analogy, with a backpack journey, a Logbook concept as an educational tool to potentially promote students’ self-reflection was developed. Compared with the control group, results indicate a positive evolution of creative thinking skills in the experimental group
Hydrogeochemical evolution of the bentonite buffer in a KBS-3 repository for radioactive waste. Reactive transport modelling of the LOT A2 experiment
No full textThe Swedish Nuclear Fuel and Waste Management Company (SKB) is conducting a series of long term tests at the ??sp?? Hard Rock Laboratory to assess the behaviour of the bentonite buffer under conditions similar to those expected in a KBS-3 repository for high level nuclear waste. The LOT A2 experiment consists of a vertical borehole with a central heater inside a copper tube surrounded by compacted bentonite. During four years, the temperature of the copper tube was maintained at 130. ??C, while the bentonite was progressively water saturated by the injection of groundwater. During this period, physical and hydro-geochemical data were collected. By using the code TOUGHREACT, a model was made to simulate the processes of solute transport which control the chemical and the mineralogical distribution observed in the bentonite at the end of the test. Additionally, a series of sensitivity analyses was performed to assess the influence of key parameters controlling the thermal-hydro-geochemical processes. Numerical results indicate that, within the first year, the heated bentonite blocks are completely water saturated, which agree with the measured data. The simulated transport of chloride, the dissolution/precipitation of Ca sulphate minerals, and the cation redistribution in the montmorillonite interlayer also agree with data measured at the end of the experiment