Repositório IC-Online
Institution's Scientific Repository
IC-Online, the Institutional Repository of Scientific Information of the Polytechnic of Leiria (IPLeiria), is part of the RCAAP Project (Open Access Scientific Repositories of Portugal). Its main objectives are to organise, preserve and disseminate the scientific production of the Polytechnic of Leiria (IPLeiria), helping to increase the visibility and impact of the institution's scientific publications.
The IC-Online Repository includes various types of digital documents, such as articles from national and international scientific journals, papers from congresses and conferences, master's dissertations and doctoral theses, among others.
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Recent Submissions
Thermal stress effects on energy resource allocation and oxygen consumption rate in the juvenile sea cucumber, Holothuria scabra (Jaeger, 1833)
Publication . Kühnhold, Holger; Kamyab, Elham; Novais, Sara; Indriana, Lisa; Kunzmann, Andreas; Slater, Matthew; Lemos, Marco
Water temperature is a key factor in aquaculture production of the commercially valuable sea cucumber Holothuria scabra. Knowledge is scarce about actual energetic costs that can be associated with internal acclimatization processes as a response to thermal extremes. In the present study changes in cellular energy allocation, oxygen consumption rate and energy related enzymes' activity (IDH and LDH) were measured in juvenile H. scabra, held at different temperatures: 21, 27 and 33 °C. The results showed that the steady temperature change (1 °C/day) to both temperature treatments, until reaching the testing temperatures (day 0), clearly affected cellular energy consumption and available energy reserves, measured in the respiratory tree and muscle tissue, respectively. However, 15 and 30 days after acclimation, the initial differences in cellular energy allocation between treatments decreased. In contrast to the variations measured in cellular energy allocation, oxygen consumption was highest at 33 °C and lowest at 21 °C at all three measurement times. Moreover, a significant positive correlation between oxygen consumption rate and temperature was detected at day 15 and day 30.
Likewise, a shift from anaerobic to aerobic energy metabolism, indicated by changes in LDH and IDH activities, was observed in the animals from the warm temperature treatment. Results imply that juvenile H. scabra were able to recover from initial disturbances in energy balance, caused by the incremental temperature change of
±6 °C. Over the experimental period of 30 days, elevated temperature did however, lead to a metabolic shift andmore efficient energy turnover, indicated by changes in oxygen consumption rate, LDH and IDH. The synergy of cellular energy allocation and oxygen consumption proved to be a viable indicator to assess the capability of
sea cucumbers like H. scabra to cope with extreme temperature conditions. Surprisingly, juvenile H. scabra were able to sustain their energy balance and oxygen consumption rate within the homeostatic range, even at 33 °C. Thus, we assume that rearing temperatures of 33 °C might be possible, which could improve aquaculture
production of H. scabra. However, further research is required to understand the mechanisms and effects of acclimation under aquaculture conditions.
Statement of relevance: The sea cucumber H. scabra is considered a promising aquaculture candidate in the tropics. The commercial interest in H. scabra has led to a great number of attempts to culture this species e.g. in Madagascar, Tanzania, India and Indonesia, where the farming of this species also showed a great potential
to increase the livelihood of the local community. Although, considerable research effort has been put into the advancement of the production cycle, fundamental knowledge, e.g. on physiological adjustments due to suboptimal rearing conditions, remains scarce for H. scabra.Water temperature has been identified as crucial factor,
determining production efficiency. In our manuscriptwe introduce an innovative approach, for the assessment of shifts in the energy budget as well as in metabolic pathways, to detect thermal stress in juvenile H. scabra. Our results show that the combined application of cellular energy allocation (CEA) and measurement of the oxygen consumption rate (OCR) as well as the activity of two metabolic key enzymes: iso-citrate dehydrogenase (IDH) and lactate dehydrogenase (LDH), is a strong analytical tool to evaluatewhole animal homeostasis under thermal extremes. To our knowledge this is the first study inwhich the method of CEAwas optimized for the application on isolatedmuscle and respiratory tree tissue of a sea cucumber, like H. scabra.Hence, our results provide original insights into the thermal acclimation physiology of H. scabra, which provides crucial knowledge for setting up
optimal culture conditions for this highly valuable aquaculture candidate.
Moreover, our results show that juvenile H. scabra were strongly affected by rapid temperature changes, exhibiting distinct differences in metabolic adjustments as response to short-term cold and warm acclimation, but were able to restore homeostatic conditions at constant cold and warm temperature extremes. Concerning aquaculture practices, these findings imply that CEA might be a good condition indicator to evaluate the overall metabolic status in sea cucumbers. Moreover, rapid temperature fluctuations seem to provoke much higher
energetic costs in juvenile H. scabra than constant extreme temperature conditions, which is important to consider in daily management practices.
The OCR revealed an enhanced metabolism at warmer temperature conditions, throughout the entire experimental period. Likewise, the warm exposed animals were shifting their energy turnover from a more anaerobic to amore aerobic state, indicated by changes in LDH and IDH activities, and showed increased foraging activity at all times. The combined outcome of CEA, OCR and activities of energymetabolismrelated enzymes indicates, that the increased metabolic activity in juvenile H. scabra, as response to warmer temperature, was well within the
homeostatic range. Thus, contrary to our expectations, a rearing temperature of up to 33 °C might presumably be favourable for the aquaculture of H. scabra.
Automatic Evaluation of Children Reading Aloud on Sentences and Pseudowords
Publication . Proença, Jorge; Lopes, Carla; Tjalve, Michael; Stolcke, Andreas; Candeias, Sara; Perdigão, Fernando
Reading aloud performance in children is typically assessed by teachers on an individual basis, manually marking reading time and incorrectly read words. A computational tool that assists with recording reading tasks, automatically analyzing
them and providing performance metrics could be a significant help. Towards that goal, this work presents an approach to automatically predicting the overall reading aloud ability of primary school children (6-10 years old), based on the reading of sentences and pseudowords. The opinions of primary school teachers were gathered as ground truth of performance, who provided 0-5 scores closely related to the expectations at the end of each grade. To predict these scores automatically,
features based on reading speed and number of disfluencies were extracted, after an automatic disfluency detection. Various regression models were trained, with Gaussian process regression giving best results for automatic features. Feature
selection from both sentence and pseudoword reading tasks gave the closest predictions, with a correlation of 0.944. Compared to the use of manual annotation with the best correlation being 0.952, automatic annotation was only 0.8% worse. Furthermore, the error rate of predicted scores relative to ground truth was found to be smaller than the deviation of evaluators’ opinion per child.
POLÍTICAS LOCAIS E IMPACTOS NA CONCEÇÃO DA EXPERIÊNCIA TURÍSTICA EM ESPAÇOS URBANOS – OS CASOS DO BAIRRO ALTO E DA MOURARIA, LISBOA
Publication . Xavier, António José Tavares da Costa; Almeida, António Sérgio Araújo de
A reabilitação urbana do património arquitetónico e monumental em bairros históricos tende a propiciar a disputa na utilização/apropriação dos “novos” espaços daí resultantes, não só por novos moradores, normalmente de classes sociais mais abastadas, mas também por novos comerciantes, mais especializados em contextos empresariais. Surgem, assim, novos espaços de residência, lazer, entretenimento e
cultura, entre outros. Apurar contributos locais para que bairros típicos proporcionassem experiências locais e turísticas diferenciadas na perspetiva da fidedignidade às origens foi um dos grandes objetivos deste trabalho. Paradoxalmente, conforme observado na cidade de Lisboa e após uma investigação realizada em 2014 e 2015, a mesma governação local de reabilitação urbana suscita ambivalências a vários níveis. Por um lado, promovendo identidades e valores que
caracterizam objetivamente a Tradição e a História num regime de reciprocidade com os habitantes locais, e, por outro lado, transformando espaços onde os valores culturais se assumem numa função comercial sem correspondência nas expectativas das gentes locais nem coerência com a autenticidade (resultante dos valores identitários) dos respetivos espaços. Enquanto no Bairro Alto permitiuse
aos investidores a decisão na apropriação e utilização do espaço, na Mouraria, registou-se um processo de governação integrada com a mobilização da população residente e forças ativas do bairro. No primeiro caso, surgiram conflitos entre novos e velhos utilizadores do bairro, assumindo-se a oferta turística como espaço de animação noturna centrada num espaço público de boémia, no consumo de álcool
e num ambiente de festa permanente No segundo caso, geraram-se sinergias propiciadoras de uma reabilitação urbana defensora da mobilização das estruturas identitárias do bairro, promovendo estilos de vida tradicionais e resgatando o seu imaginário coletivo assente nos seus próprios sistemas de valores. Na Mouraria, observa-se um Turismo comunitário, envolvendo gentes locais, que, apropriando-se do seu espaço turístico, o projetam no pressuposto de consubstanciar
objetivamente o seu património numa experiência turística diferenciada.
Solving boundary value problems on manifolds with a plane waves method
Publication . Alves, Carlos J. S.; Antunes, Pedro R. S.; Martins, Nuno F. M.; Valtchev, Svilen S.
In this paper we consider a plane waves method as a numerical technique for solving boundary value problems for linear partial differential equations on manifolds. In particular, the method is applied to the Helmholtz–Beltrami equations. We prove density results that justify the completeness of the plane waves space and justify the approximation of domain and boundary data. A-posteriori error estimates and numerical experiments show that this simple technique may be used to accurately solve boundary value problems on manifolds.
Behavioral regulation in sport questionnaire and sport motivation scale-II: a scale comparison
Publication . Bica, Joana; Susano Jacinto, Miguel Ângelo; Matos, Rui; Amaro, Nuno; Antunes, Raul; Couto, Nuno; Cid, Luis; Forte, Pedro; Monteiro, Diogo
Introduction: This study compared the psychometric properties of two primary
instruments for assessing sport motivation based on Self-Determination Theory:
the Sport Motivation Scale-II (SMS-II) and the Behavioral Regulation in Sport
Questionnaire (BRSQ).
Methods: A cross-sectional analysis evaluated the scales’ internal consistency,
factor structure, convergent and discriminant validity, and model fit, which
required post-hoc modifications. Measurement invariance and adherence to
the theoretical simplex pattern were also tested.
Results: The BRSQ demonstrated generally acceptable reliability, while the SMS-II
showed deficiencies in its introjected, external, and amotivation subscales. Both
scales faced validity challenges in distinguishing adjacent motivational constructs.
Although measurement invariance was supported, correlations deviated from the
theoretical quasi-simplex pattern.
Discussion: The BRSQ appears more robust, but neither scale is flawless. Researchers
must select instruments aligned with their specific objectives and interpret scores
cautiously due to these psychometric limitations. This underscores the need for
refined tools to better capture the dynamic complexity of motivation in sports.