3,888 research outputs found
Sediment concentration and particle size in the water column using acoustic methods : Application to the Douro and Minho Estuaries
Most Portuguese fluvial systems are subject to flow regularization through construction of dams and reservoirs. Such structures are responsible for significant changes in estuarine configuration, modifying the natural discharge patterns and trapping the fluvial sediments upstream, decreasing the fluvial contribution to the coastal sediment budget. Sediment export estimates reveal a severe sediment deficit and an accentuated erosive tendency in some segments of the NW Portuguese coast. In this context, the quantification and qualification of the present effective sediment exchanges between estuaries and the coastal shelf is crucial to determine the consequent implications of urgent coastal management actions. In order to address this problem, the implementation of pragmatic monitoring solutions and the compilation of previously collected data has become a priority in order to establish the present sediment dynamic regime in this area.
In the past, several long term datasets of Acoustic Doppler Current Profilers were collected in Portuguese transitional areas covering different seasonal regimes. These datasets, collected with diverse objectives in mind, were processed and interpreted to establish the hydrodynamic regime in their respective study areas, but no attempt was made to establish suspended sediment patterns during the duration of their deployment.
The possibility of extracting estimates of sediment concentration and grain size from these ADCP datasets is explored in this research, and the results from these findings are then used to reprocess and reinterpret datasets collected in two major NW Portuguese estuaries: The Douro and the Minho. As a final objective we aim to quantify and qualify the effective sediment exchanges from these estuaries and the coastal shelf, and consequently determining the fate and destination of these sediments, by describing different seasonal transport patterns based on sediment dynamics conceptual models of both estuaries built based on previously collected ADCP data time series
MÃnimos de funcionais integrais e a validade da equação de Euler-Lagrange
Mestrado em MatemáticaNesta dissertação estudam-se problemas de mÃnimo, com especial atenção ao
problema clássico do Cálculo das Variações. Nomeadamente, após algumas
considerações gerais, estuda-se a existência de mÃnimos para certas classes
de funcionais, incluindo os funcionais integrais do Cálculo das Variações e
prova-se a existência de mÃnimos Lipschitzianos para funcionais integrais sob
a "Condição de Pendência Limitada".
Na segunda parte apresenta-se a equação de Euler-Lagrange como condição
necessária para a existência de mÃnimos ilustrando a sua utilidade e a sua
relação com o Fenómeno de Lavrentiev.
O último capÃtulo contém uma apresentação de resultados recentes sobre a
validade da equação de Euler-Lagrange e sobre o Fenómeno de Lavrentiev.
ABSTRACT: In this dissertation minimum problems, with special attention to the classic
problem of the Calculation of the Variations, are studied. Namely, after some
general considerations, the existence of minimum for certain functional
classes, are studied, including the integral functional for the classic problem of
the Calculus of Variations and under the Bounded Slope Condition, the
existence of Lipschitzians minimum for the integral functional.
In the second part we present the Euler-Lagrange equation as necessary
condition for the existence of minimum illustrating its usefulness and its relation
with Lavrentiev phenomenon.
The last chapter contains a presentation of recent results on Euler-Lagrange
equation’s validity and the Lavrentiev phenomenon
Tomada de decisão de profissionais sobre a retirada de menores à famÃlia biológica
Dissertação de mestrado integrado em Psicologia (área de especialização em Psicologia Escolar e da Educação)A proteção de menores constitui uma preocupação relativamente recente em Portugal. Nesse
âmbito, tem vindo a ser desenvolvido um edifÃcio legislativo e institucional complexo que visa
proteger o melhor possÃvel o denominado superior interesse da criança. Alguma indefinição de
conceitos, de critérios e de competências, torna complexo e por vezes conflituoso o procedimento
relativamente aos menores em risco.
O presente estudo, tem como objetivo compreender de que forma sujeitos envolvidos nos
complexos processos de proteção de menores ponderam a retirada de crianças e jovens à s famÃlias.
Para estudar esta questão foi utilizado um questionário colocado numa plataforma online composto
por 4 casos (vinhetas) que retratavam situações de abuso e relativamente aos quais se pedia a opinião e
percepção de diversos profissionais potencialmente envolvidos. No estudo, participarem 103 sujeitos,
entre Magistrados/ Juristas, Professores, Psicólogos e Educadores/ Assistentes Sociais.
A partir das análises verificou-se que os participantes de diferentes grupos profissionais
utilizam diferentes tipos de informação e caracterÃsticas dos casos aquando da tomada de decisão
sobre a retirada de menores. No geral, a gravidade do abuso e o risco de recorrência são as
caracterÃsticas com ponderação mais elevada no momento da decisão. Contudo, os Educadores/
Assistentes Sociais são os que mais desvalorizam a caracterÃstica referida. O local de trabalho dos
participantes não influencia significativamente as suas percepções no que diz respeito à valoração das
caracterÃsticas do maltrato.
Os resultados do estudo confirmam a complexidade do processo de tomada de decisão referida
noutros estudos. A filiação profissional aparenta exercer uma maior influência na tomada de decisão,
ao contrário dos fatores pessoais como o sexo e as habilitações literárias e do local de trabalho.The child protection is a recent issue in Portugal. In this extend, it has been developed a set of
complex institutional legislation with the objective to protect children’s best interest. Sometimes,
there is concept vagueness, as well as a criteria and abilities’ uncertainty, which makes the all process
complex and quarrelsome.
The present study pretends to understand how professionals involved in making these kind of
decisions prioritize and use particular kind of information. In order to study this question, it was used
an online questionnaire, which consisted of 4 vignettes (cases) representing child and youth
maltreatment situations. A total of 103 participants – Magistrates/ Lawyers, Teachers, Psychologists
and Social Educators and Assistants, responded to the questionnaire.
Analyses of reactions to the vignettes demonstrated that professional groups use different
kinds of information when making decisions about foster care placements. In general, the
professionals rely the decision on information about severity of the abuse and likelihood of recurrence.
Nevertheless, the Social Educators/ Assistants were the ones who care less about the stated
information. The work place does not affect significantly the professionals’ perceptions in what
concerns the maltreatment characteristics’ valuation.
The decision-making process’s complexity is confirmed by this study results. Professional
membership seems to be more influence on decision-making then professionals’ work company and
personal factors as sex and academic qualifications
Nitric Oxide Regulates Neurogenesis in the Hippocampus following Seizures
Hippocampal neurogenesis is changed by brain injury. When neuroinflammation accompanies injury, activation of resident microglial cells promotes the release of inflammatory cytokines and reactive oxygen/nitrogen species like nitric oxide (NO). In these conditions, NO promotes proliferation of neural stem cells (NSC) in the hippocampus. However, little is known about the role of NO in the survival and differentiation of newborn cells in the injured dentate gyrus. Here we investigated the role of NO following seizures in the regulation of proliferation, migration, differentiation, and survival of NSC in the hippocampus using the kainic acid (KA) induced seizuremouse model. We show that NO increased the proliferation of NSC and the number of neuroblasts following seizures but was detrimental to the survival of newborn neurons. NO was also required for the maintenance of long-term neuroinflammation. Taken together, our data show that NO positively contributes to the initial stages of neurogenesis following seizures but compromises survival of newborn neurons.Foundation for Science and Technology (FCT, Portugal); COMPETE; FEDER [PTDC/SAU-NEU/102612/2008, PTDC/NEU-OSD/0473/2012, PEst-C/SAU/LA0001/2013-2014, PEst-OE/EQB/LA0023/2013-2014]; FCT, Portugal [SFRH/BPD/78901/2011, SFRH/BD/77903/2011
Critical Literacy and Literacies
Literacy emerged as a concept that meant the application of reading, writing and numeracy skills in the individual’s everyday context. Nowadays, the concept of literacy takes on a central and multivariate dimension and is mobilized in several contexts, such as digital literacy, sustainability literacy and ocean literacy, just to name a few. This paper seeks to discuss these multiplicities of literacies through an approach supported in the critical literacy concept, as well as the implications of this stance
Governance and tax management : does it matter? Evidence from Spain
Mestrado em Contabilidade, Fiscalidade e Finanças EmpresariaisEste estudo tem por objectivo investigar o papel do governo das sociedades na gestão fiscal. Isto é feito analisando 103 empresas espanholas cotadas através de quatro regressões diferentes, cada uma associada a um mecanismo de governo das sociedades distinto: (1) composição do conselho de administração, (2) caracterÃsticas do CEO, (3) estrutura compensatória dos directores e (4) estrutura de detenção. Os resultados obtidos confirmam a literatura existente sobre este tema, demonstrando que o governo das sociedades tem, de facto, um impacto importante na gestão fiscal. As conclusões mostram também que os accionistas (e não apenas os gestores) podem estar interessados em reduzir a carga fiscal das empresas, uma vez que esta é uma oportunidade para aumentar o desempenho destas e ganhar mais dinheiro. Este estudo pode ajudar a compreender como os legisladores podem reduzir as situações em que os impostos são geridos de forma excessiva e ajudar a definir as polÃticas corporativas das empresas.This paper investigates the role of corporate governance devices on tax management. This is done by analysing 103 Spanish listed firms through four different regressions models, each associated with a different corporate governance mechanism: (1) board of directors' composition, (2) CEO's characteristics, (3) directors' compensation structure and (4) ownership structure. Extending existing literature on this subject, the results support the view that corporate governance has, in fact, an important impact on tax management. The conclusions also support the idea that shareholders (and not only managers) may be interested in reducing the firms' tax burden, as it is an opportunity to improve its performance and earn more money. The present study may provide insights into how legislators may reduce situations where taxes are managed in an excessive way and help define the firms' corporate policies
Stabilizing High Energetic States of Pharmaceutical Drugs
Modification of the physical state of low soluble drugs, as amorphization, is a promissory strategy to increase their solubility, since this intrinsically disordered state promotes solubilisation. In the present work, a composite has been prepared and characterized aiming to improve the aqueous solubility of a drug by amorphization, and able to be used for controlled drug delivery.
Simvastatin (SIM) is the target drug, belonging to statins family, used to reduce the levels of cholesterol in blood and with high efficiency in bone regeneration. To achieve SIM’s amorphization, it was incorporated in unmodified and surface treated by methylation SBA-15 mesoporous matrices. Nuclear magnetic resonance and infrared spectroscopy together with thermogravimetric analysis evidenced efficient inclusion in matrices and the absence of strong guest-host interactions. Native SIM’s phase transformations were studied by differential scanning calorimetry, allowing the identification of melting close to 140 ºC. After cooling from the melt, crystallization is avoided and SIM solidifies in a glassy state. The glass transition, detected in subsequent heating, is clearly seen with a midpoint temperature (Tg.mid) of 33 ºC. In the composites the glass transition is also detected showing that the drug is in the amorphous state, however emerging at higher temperature compared with the native drug. Dielectric Relaxation Spectroscopy results of incorporated SIM indicate that molecular motions are hindered by the presence of the silica matrix, in agreement with the calorimetric Tg’s increase.
Cytotoxicity assays were performed using confluent and non-differentiated Caco-2 cells. The results demonstrate that at higher concentrations simvastatin is less cytotoxic when incorporated in the silica pores.
Release assays were done to simulate drug delivery in the organism using conditions similar to intestinal fluid such as pH 6.8. Monitoring by UV-Vis spectroscopy revealed that simvastatin is easily released from both silicas. Preliminary results suggest a faster release from the unmodified silica. Both assays allow concluding that the studied composites are promissory to be used as drug delivery systems.
The work here reported was accepted to be presented as a poster communication in Chempor 2018
Literacy: Promoting Sustainability in a Digital Society
We increasingly live simultaneously immersed in physical interactions and in a world where the digital dimension is present at various levels, such as the social, economic and political ones. In this context, the relationship between the digital world and Sustainability is pivotal. This aim of this paper is to discuss, in a reasoned manner, the importance of literacy in the promotion of sustainability in a digital society. For this purpose, the results of a literature review will be mobilized, as well as our 20 years of experience in teaching and research in the fields of sociology, education and organizations, without forgetting the publications that we have on similar topics, which will be, whenever heuristically relevant, mobilized to substantiate and justify the arguments presented herein. The conclusions show that, in a reality where the digital involves many of the life dimensions—for example, in the form of Industry 4.0 and Society 5.0—the role of literacy and, in particular, digital literacy, are critical in the development of sustainability literacy. For this to be possible, significant training work must be carried out. Furthermore, it is not possible to assume that the access, the skills in its use and the benefits of this wonderful digital world will automatically be grasped and felt by all citizens, in an ideology that must be fought. Only in this way will it be possible to foster sustainability, which must necessarily be inclusive
Heat transfer enhancement using nanofluids in the compression exchanger in a solar Stirling engine
In this paper a improvement in the heat exchange of a solar Stirling engine
during the compression phase was studied. The viability of using nanoparticles as
ceramic oxide (Al2O3 in water) at different concentrations instead of conventional
refrigerants (water or air) was evaluated. Since these systems could behave as non-
Newtonian fluids the dynamic viscosity was measured, as well as other thermophysical
properties. The results showed that the convective heat transfer coefficient could raise
one order of magnitude respect to the conventional heat transfer fluids at moderately
volume fractions (over 0.15).Universidad de Málaga. Campus de Excelencia Internacional AndalucÃa Tec
Práticas Pedagógicas de Abordagem à Linguagem Escrita em Jardim-de-Infância
VII Simpósio Nacional de Investigação em Psicologia, Universidade do Minho, Portugal, 4 a 6 de Fevereiro de 2010.Este estudo procura descrever e analisar as práticas pedagógicas de um grupo de educadoras de infância portuguesas no domÃnio da abordagem à linguagem escrita, para determinar quais os aspectos centrais numa intervenção que se pretende de literacia emergente. A partir da observação de 18 educadoras de infância, em aspectos tais como a concepção de um projecto de intervenção, a organização e gestão de espaços e tempos e a implementação de estratégias directas de intervenção, foram seleccionadas três educadoras que, representando diferentes modelos pedagógicos, obtiveram melhores resultados. As práticas pedagógicas destas educadoras foram observadas durante um ano lectivo. Os resultados permitem-nos afirmar que, se por um lado, as práticas pedagógicas das 18 educadoras são caracterizadas por uma descontinuidade ao nÃvel dos diversos componentes da sua prática, quando aprofundamos as três que melhores resultados obtiveram, verificamos uma progressiva articulação desses componentes numa aproximação mais coerente e coesa à abordagem emergente da literacia
- …