Browsing by Author "Costa, C."
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- Developing self-guided scuba dive routes in the Algarve (Portugal) and analysing visitors' perceptionsPublication . Rangel, Mafalda; Pita, C. B.; Gonçalves, J. M. S.; Oliveira, F.; Costa, C.; Erzini, KarimScuba diving allows for underwater visitation of cultural and natural resources. Underwater routes can be used as a tool for guided and supervised underwater visits. Two scuba diving routes were implemented in the Algarve (South of Portugal), the "B24" and "Poco" diving sites. The perceptions of scuba divers regarding several aspects of the routes and the existing support infrastructures were studied following a survey carried out through face-to-face interviews from 2008 to 2012. Divers profile and their perceptions were analysed using 246 valid questionnaires. Divers were mainly Portuguese, over 30 years old and with more than 12 years of formal education. Some of the support infrastructures did not achieve a "good" or "acceptable" grade. This should be carefully considered by diving operators and managers, because perceptions tend to circulate throughout the diving tourists. All features of interpretative slates were graded as highly satisfactory. Overall, diver satisfaction increased slightly after route implementation, with an average ranking of "good". These findings support the implementation of underwater routes as a way to promote diving activity, and to increase divers' environmental education and awareness. (C) 2013 Elsevier Ltd. All rights reserved.
- Eco-touristic snorkelling routes at Marinha beach (Algarve): Environmental education and human impactsPublication . Rangel, Mafalda; Pita, C. B.; Gonçalves, J. M. S.; Oliveira, F.; Costa, C.; Erzini, KarimThe use of natural areas for underwater coastal marine activities such as snorkelling is growing, but the amount of ecological and socioeconomic data on these activities is scarce and relates mainly to coral reef areas. Three underwater self-guided routes were designed at Marinha Beach (Algarve, Portugal), based on scientific information, with in situ interpretation and guidance, as a way to enhance biodiversity awareness and, hence, reduce the probability of human impacts. The routes were implemented in two consecutive summer seasons and after each season, visual census techniques were used to describe flora composition and cover area (seaweeds and seagrasses) in order to understand patterns and evaluate human impacts. Snorkelers' opinions and perceptions about several issues related to the routes' environmental education role (e.g. role in enhancing biocliversity awareness) were investigated by questionnaire after the snorkelling activity. An inter-annual difference inflora assemblages was found, probably associated to natural variability, rather than snorkelers' impacts. Results indicate that, in fact, in situ education and interpretation can raise environmental awareness if properly addressed, resulting in a satisfactory way of engaging snorkelers in the protection and in the conservation of the visited environments, thereby preventing negative ecological impacts. (C) 2015 Elsevier Ltd. All rights reserved.
- Emulsion formation and stabilization by biomolecules: the leading role of cellulosePublication . Costa, C.; Medronho, Bruno; Filipe, Alexandra; Mira, I.; Lindman, B.; Edlund, H.; Norgren, M.Emulsion stabilization by native cellulose has been mainly hampered because of its insolubility in water. Chemical modification is normally needed to obtain water-soluble cellulose derivatives. These modified celluloses have been widely used for a range of applications by the food, cosmetic, pharmaceutic, paint and construction industries. In most cases, the modified celluloses are used as rheology modifiers (thickeners) or as emulsifying agents. In the last decade, the structural features of cellulose have been revisited, with particular focus on its structural anisotropy (amphiphilicity) and the molecular interactions leading to its resistance to dissolution. The amphiphilic behavior of native cellulose is evidenced by its capacity to adsorb at the interface between oil and aqueous solvent solutions, thus being capable of stabilizing emulsions. In this overview, the fundamentals of emulsion formation and stabilization by biomolecules are briefly revisited before different aspects around the emerging role of cellulose as emulsion stabilizer are addressed in detail. Particular focus is given to systems stabilized by native cellulose, either molecularly-dissolved or not (Pickering-like effect).
- Microrheology of novel cellulose stabilized oil-in-water emulsionsPublication . Medronho, Bruno; Filipe, A.; Costa, C.; Romano, Anabela; Lindman, B.; Edlund, H.; Norgren, M.Diffusing wave spectroscopy (DWS) is a powerful optical technique suitable to investigate turbid samples in a nondestructive and reproducible way, providing information on the static and dynamic properties of the system. This includes the relative displacement of emulsion droplets over time and changes in the viscoelastic properties. Here, novel and promising cellulose-based oil-in-water (O/W) emulsions were prepared and studied, for the first time, by DWS. Cellulose plays the role of a novel eco-friendly emulsifying agent. The hydrolysis time of cellulose was observed to affect the average size of the emulsion droplets and their stability; the longer the hydrolysis time, the more dispersed and stable the emulsions were found to be. Additionally, a good complementarity between the microrheology (DWS) and macrorheology (mechanical rheometer) data was found. Our work suggests that DWS is a highly attractive method to investigate the stability, aging and microrheology properties of cellulose-based emulsions, providing valuable insights on their microstructure. This technique is thus highly appealing for the characterization and design of novel emulsion formulations. (C) 2018 The Authors. Published by Elsevier Inc.
- Predictors of myositis in mixed connective tissue disease: a multicentre retrospective studyPublication . Melo, A. T.; António, M. Silvério; Martinho, J. Martins; Guimarães, F.; Dourado, E.; Oliveira, D.; Lopes, J.; Saraiva, A.; Gago, A.; Correia, M.; Fernandes, A. L.; Dinis, S.; Teixeira, R.; Silva, S. P.; Costa, C.; Beirão, T.; Furtado, C.; Abreu, P.; Khmelinskii, N.Objectives: We aimed to identify clinical and serological predictors of myositis in mixed connective tissue disease (MCTD). Methods: We performed a nationwide, retrospective, multicentre study including adult-onset MCTD patients fulfilling at least one of the following diagnostic criteria: Sharp’s, Kasukawa, Alarcón-Segovia, or Kahn’s. Univariable analysis was performed using Chi-square, Fisher exact, Student’s t or Mann-Whitney U tests, as appropriate. Multivariable analysis was performed using binary logistic regression. Results: Ninety-eight patients were included. Myositis was observed in 43.9% of patients, of whom 60.5% had myositis at disease onset. Proximal muscle weakness was described in 30 patients with muscle involvement (70%). Gastrointestinal involvement was identified in 28% and respiratory involvement in 29% of myositis patients. In the same subgroup of patients, 41.7% had a myopathic pattern on electromyography, and 47.1% had histological myositis features in the muscle biopsy. Fever (OR=6.96, p=0.022) was an independent predictor of myositis, regardless of sex, age at diagnosis, ancestry, and respiratory involvement. African ancestry (OR=8.39, p=0.019), leukopenia at the disease onset (OR 6.24, p=0.021), and younger age at diagnosis (OR=1.07/year, p=0.035) were identified as independent predictors of myositis at disease onset, regardless of sex and scleroderma pattern in capillaroscopy. Conclusions: Myositis is a common manifestation of MCTD, even at the disease onset. African ancestry, leukopenia at the disease onset, younger age at diagnosis, and fever should prompt a thorough evaluation for myositis.
- The use of animal bone as fuel in the third millennium BC walled enclosure of Castanheiro do Vento (Northern Portugal)Publication . Costa, C.Experiments on fire manipulation of bones as fuel demonstrated that animal bones are effective in the act of maintaining lasting combustion. These experiments are almost always applied to the studies in hunter-gather societies in prehistory, even though the use of bones as fuel is also known in historical times. Based on data and models resulting from these recent experiments, both in laboratory and in real hearths, I tested the hypothesis of the use of animal bone as fuel in the third/second millennium BC walled enclosure of Castanheiro do Vento, in northern Portugal. The faunal assemblage shows some specific characteristics such as a very low percentage of identifiable material and close to 90% of charred bones with a very high index of fragmentation I link the faunal analysis with the results of some experiments recently published. These experiments show the particularities of bone fuel combustion, specifically used in certain activities. Nevertheless, the interpretation of these activities in Castanheiro do Vento is difficult to achieve because of the preliminary state of the investigations. As an additional problem, the available interpretations in the literature concern mostly hunter-gather, and models do not take into account the complex societies of the third/second millennium BC. Copyright (c) 2015 John Wiley & Sons, Ltd.