Browsing by Issue Date, starting with "2023-07"
Now showing 1 - 10 of 71
Results Per Page
Sort Options
- Upside/downside spillovers between oil and Chinese stock sectors: from the global financial crisis to global pandemicPublication . Mensi, Walid; Hanif, Waqas; Vo, Xuan Vinh; Choi, Ki-Hong; Yoon, Seong-MinThis paper examines the effects of the COVID-19 outbreak, recent oil price fall, and both global and European financial crises on dependence structure and asymmetric risk spillovers between crude oil and Chinese stock sectors. Using time-varying symmetric and asymmetric copula functions and the conditional Value at Risk measure, we provide evidence of positive tail dependence in most sectors using copula and conditional Value-at-Risk techniques. We can see the average dependence between oil and industries during the oil crisis. Moreover, we find strong evidence of bidirectional risk spillovers for all oil-sector pairs. The intensity of risk spillovers from oil to all stock sectors varies across sectors. The risk spillovers from sectors to oil are substantially larger than those from oil to sectors during COVID-19. Furthermore, the return spillover is time varying and sensitive to external shocks. The spillover strengths are higher during COVID-19 than financial and oil crises. Finally, oil do not exhibit neither hedge nor safe-haven characteristics irrespective of crisis periods.
- Modern advancement in biotechnological applications for wastewater treatment through microalgae: a reviewPublication . Goyal, Shubham; Dhanker, Raunak; Hussain, Touseef; Ferreira, Alice; Gouveia, Luisa; Kumar, Krishna; Mohamed, Heba I.Microalgae are microscopic organisms that have a broad range of applications, from wastewater treatment, CO2 mitigation to therapeutic proteins, and pharmaceuticals. Recently, the combination of wastewater treatment-based microalgae and the use of the obtained biomass as biofertilizers/stimulants/pesticides have been highly emphasized for their use in the agriculture field. Biofertilizers are a need of today's agriculture practices due to the increasing demand for food to feed a hungry planet while avoiding chemical contamination by the over-application of synthetic fertilizers. There is a constant need for modern techniques for the use of microalgae in a sustainable manner to harness their products to their full extent. Various types of bioreactors are available on the market, each with its own advantages and disadvantages, which, based on their efficiency, can be used for microalgae cultivation. This review aims at reporting recent developments in microalgae biotechnology, especially related to CO2 mitigation, wastewater purification, biofuel, feedstock, future food, therapeutic proteins, pharmaceuticals, and biofertilizers, highlighting some of the current research in this field and future development priorities.
- Non-ketotic hyperglycaemia induced occipital reflex focal seizuresPublication . Buque, Helena; Catamo, Deise; Felix, Catarina; André, Ana; Gil, Inês; Nzwalo, HipólitoA myriad of neurological manifestations can occur in association with ketotic and non ketotic hyperglycaemic states. Contrary to diabetic coma, which is a universal complication under relatively established metabolic circumstances, the pathophysiology beyond hyperglycaemicassociated positive neurological manifestations, including seizures, remains to be elucidated. The occurrence of symptomatic focal epilepsy as a manifestation of diabetes-related hyperglycaemia is seldom reported. Herein, we present a case of focal epilepsy with alternating positive and negative neurological manifestations as the initial manifestation of diabetes-related hyperglycaemia. The electroencephalogram confirmed the diagnosis of focal occipital seizures, and the brain magnetic resonance imaging depicted the associated typical transient imaging findings in the occipital lobe. Seizures were refractory to antiepileptics, and symptomatic control was achieved after achieving normoglycemia. On follow-up, complete clinical and imaging recovery occurred. Reflex focal epilepsy in the context of hyperglycaemic states is a rare condition, and the possibility of misdiagnosis is likely high. As reported in similar cases, seizures can be resistant to antiepileptics. An important message to highlight is that seizures associated with hyperglycaemic status can be resistant to antiepileptic treatment and only cease with glycaemic control.
- Co-limitation of phytoplankton by N and P in a shallow coastal lagoon (Ria Formosa): implications for eutrophication evaluationPublication . Domingues, Rita B.; Nogueira, Patricia; Barbosa, Ana B.The Ria Formosa coastal lagoon is a highly productive shallow ecosystem in southern Portugal, subjected to nutrient inputs from anthropogenic and natural sources. Nutrients are major abiotic drivers of phytoplankton in this system, but their effects on phytoplankton assemblages and the occurrence of nutrient limitation are still poorly understood. The main goal of this study was, thus, to evaluate the occurrence, type, and effects of nutrient limitation on phytoplankton community and specific functional groups in the Ria Formosa coastal lagoon. We conducted nutrient enrichment experiments with factorial additions of nitrogen (N) and phosphorus (P) using natural phytoplankton assemblages from distinct locations in the Ria Formosa, throughout a yearly cycle. Phytoplankton composition and abundance were evaluated using inverted and epifluorescence microscopies, and spectrophotometric methods were used for biomass. Limitation was defined as higher phytoplankton growth following enrichment with a particular nutrient in relation to the non-enriched control. The most common type of phytoplankton limitation was simultaneous co-limitation by N and P; diatoms, as r-strategists, were the most frequently limited group. Single N and P limitation, and serial P limitation were also observed, as well as negative responses to nutrient enrichment. Group-specific responses to nutrient enrichment were not reflected in the relative abundance of phytoplankton groups within the whole assemblage, due to the numerical dominance of pico-sized groups (cyanobacteria and eukaryotic picophytoplankton). Ambient nutrient ratios and concentrations did not predict phytoplankton nutrient limitation, given the different nutrient utilisation traits among phytoplankton functional groups. Therefore, nutrient ratios should not be used as indicators of nutrient limitation in eutrophication assessment.
- Pliocene hominins from East Turkana were associated with mesic environments in a semiarid basinPublication . Villaseñor, Amelia; Uno, Kevin T.; Kinyanjui, Rahab N.; Behrensmeyer, Anna K.; Bobe, René; Advokaat, Eldert L.; Bamford, Marion; Carvalho, Susana; Hammond, Ashley S.; Palcu, Dan V.; Sier, Mark J.; Ward, Carol V.; Braun, David R.During the middle Pliocene (similar to 3.8-3.2 Ma), both Australopithecus afarensis and Kenyanthropus platyops are known from the Turkana Basin, but between 3.60 and 3.44 Ma, most hominin fossils are found on the west side of Lake Turkana. Here, we describe a new hominin locality (ET03-166/168, Area 129) from the east side of the lake, in the Lokochot Member of the Koobi Fora Formation (3.60-3.44 Ma). To reconstruct the paleoecology of the locality and its surroundings, we combine information from sedimentology, the relative abundance of associated mammalian fauna, phytoliths, and stable isotopes from plant wax biomarkers, pedogenic carbonates, and fossil tooth enamel. The combined evidence provides a detailed view of the local paleoenvironment occupied by these Pliocene hominins, where a biodiverse community of primates, including hominins, and other mammals inhabited humid, grassy woodlands in a fluvial floodplain setting. Between <3.596 and 3.44 Ma, increases in woody vegetation were, at times, associated with increases in arid-adapted grasses. This suggests that Pliocene vegetation included woody species that were resilient to periods of prolonged aridity, resembling vegetation structure in the Turkana Basin today, where arid-adapted woody plants are a significant component of the ecosystem. Pedogenic carbonates indicate more woody vegetation than other vegetation proxies, possibly due to differences in temporospatial scale and ecological biases in preservation that should be accounted for in future studies. These new hominin fossils and associated multiproxy paleoenvironmental indicators from a single locale through time suggest that early hominin species occupied a wide range of habitats, possibly including wetlands within semiarid landscapes. Local-scale paleoecological evidence from East Turkana supports regional evidence that middle Pliocene eastern Africa may have experienced large-scale, climate-driven periods of aridity. This information extends our understanding of hominin environments beyond the limits of simple wooded, grassy, or mosaic environmental descriptions. (c) 2023 Elsevier Ltd. All rights reserved.
- Uma janela educativa para o oceano Jurássico - o Planalto do EscarpãoPublication . Oliveira, Sónia; Veiga-Pires, C.; Moura, Delminda; Pereira, L.Situado na região mais a sudoeste da Europa, o aspirante a Geoparque Mundial da Unesco Algarvensis (aUGGp Algarvensis) é um território identitário e inspirador que visa contribuir para uma maior coesão social e territorial dos concelhos de Loulé, Silves e Albufeira, através de uma política de valorização do território, baseada no conceito de Geoparque UNESCO, com o apoio da Universidade do Algarve. O aUGGp Algarvensis possui um património geológico de relevo internacional e nacional sobre uma área territorial com cerca de 1381 km2 , e pertencente a três concelhos do Algarve central. O Projeto coliderado pela Universidade do Algarve e o Centro de Investigação Marinha e Ambiental (CIMA|Arnet-Ualg) alia uma estratégia de geoconservação e um conjunto de políticas de educação e sensibilização ambiental, à promoção de um desenvolvimento socioeconómico sustentável baseado em atividades de geoturismo, envolvendo as comunidades locais e contribuindo para a valorização e promoção dos produtos locais. Esta estratégia de desenvolvimento sustentável conjugada à geologia da região permitiu definir os limites do aUGGp Algarvensis, formando um território coeso que não se estende até ao mar e que tem 48,8 % da sua área constituída por freguesias consideradas com baixa densidade populacional. O seu território e as suas paisagens cromáticas são os testemunhos de uma história geológica que conta o nascimento e aplanamento de cadeias montanhosas (Pérmico e Triásico) e mares antigos (Carbonífero e Jurássico), e se estende desde muito antes dos continentes terem a sua configuração atual, ou mesmo dos dinossauros existirem, até aos dias de hoje (Quaternário). As paisagens superficiais e subterrâneas do território do aUGGp Algarvensis escondem uma grande geodiversidade de geossítios, cujo levantamento e inventariação ainda se encontram em curso.
- Dissemination report on preliminary findings of the T-rELMA research project july 2023Publication . Torkington, Kate; Ribeiro, Filipa Perdigão; Rebelo, Sandra; Conceição, SusanaThis report follows the seminar on Algarve Tourism: Sustainability, Competitiveness and Entrepreneurship, jointly organised by the T-rELMA and IMPACTUR Algarve research project teams at the School of Management, Hospitality &Tourism, University of the Algarve, on 22June 2023.
- Amino acids profile of 56 species of microalgae reveals that free amino acids allow to distinguish between phylogenetic groupsPublication . León-Vaz, Antonio; Giráldez, Inmaculada; Moreno-Garrido, Ignacio; Varela, João; Vigara, Javier; León, Rosa; Cañavate, José PedroMicroalgae represent a phototrophic resource with a high protein content, whose nutritional value is very high as a result of its amino acid profile. Although the total amino acid profile has been repeatedly described to change little among phylogenetic groups of microalgae, some variability has occasionally been reported. Part of this uncertainty is associated with the low phylogenetic diversity encompassed in the work to date and the high methodological variability between studies. Among these studies, very few have differentiated between total and free amino acid content for common microalgae samples. Thus, in the present work, the profile of total and free amino acids has been determined in a diverse group composed of 56 species of microalgae belonging to 7 phyla. A multivariate analysis of the total amino acid profile in the studied microalgae group revealed close amino acid patterns throughout microalgae phylogeny and agreed with results obtained from similar analysis performed with published data. Conversely, the free amino acid profile strongly differentiated between phylogenetic groups. On the one hand, species of Cyanobacteria, Plantae, Cryptophyta, and Bacillariophyta showed close free amino acid patterns, characterized by the highest abundance of free glutamic acid. Ochrophyta species were particularly rich in free proline, while the free amino acid profile of Miozoa and Haptophyta species stood out from the rest of the phylogenetic groups for their outstanding levels of the two essential amino acids phenylalanine and lysine. Haptophyta species were also characterized by their much higher free tyrosine content.
- Uncovering archaeological sites in airborne LiDAR data with data-centric artificial intelligencePublication . Canedo, Daniel; Fonte, João; Seco, Luis Gonçalves; Vázquez, Marta; Dias, Rita; Pereiro, Tiago do; Hipólito, João; Menéndez-Marsh, Fernando; Georgieva, Petia; Neves, António J. R.Mapping potential archaeological sites using remote sensing and artificial intelligence can be an efficient tool to assist archaeologists during project planning and fieldwork. This paper explores the use of airborne LiDAR data and data-centric artificial intelligence for identifying potential burial mounds. The challenge of exploring the landscape and mapping new archaeological sites, coupled with the difficulty of identifying them through visual analysis of remote sensing data, results in the recurring issue of insufficient annotations. Additionally, the top-down nature of LiDAR data hinders artificial intelligence in its search, as the morphology of archaeological sites blends with the morphology of natural and artificial shapes, leading to a frequent occurrence of false positives. To address this problem, a novel data-centric artificial intelligence approach is proposed, exploring the available data and tools. The LiDAR data is pre-processed into a dataset of 2D digital elevation images, and the known burial mounds are annotated. This dataset is augmented with a copy-paste object embedding based on Location-Based Ranking. This technique uses the Land-Use and Occupation Charter to segment the regions of interest, where burial mounds can be pasted. YOLOv5 is trained on the resulting dataset to propose new burial mounds. These proposals go through a post-processing step, directly using the 3D data acquired by the LiDAR to verify if its 3D shape is similar to the annotated sites. This approach drastically reduced false positives, attaining a 72.53% positive rate, relevant for the ground-truthing phase where archaeologists visit the coordinates of proposed burial mounds to confirm their existence.
- Measuring healthy ageing: current and future toolsPublication . Silva, Nádia; Rajado, Ana Teresa; Esteves, Filipa; Brito, David V.C.; Apolónio, Joana; Roberto, Vânia; Binnie, Alexandra; Araújo, Inês Maria; Nóbrega, Clévio; Bragança, José; Castelo-Branco, PedroHuman ageing is a complex, multifactorial process characterised by physiological damage, increased risk of age-related diseases and inevitable functional deterioration. As the population of the world grows older, placing significant strain on social and healthcare resources, there is a growing need to identify reliable and easy-to-employ markers of healthy ageing for early detection of ageing trajectories and disease risk. Such markers would allow for the targeted implementation of strategies or treatments that can lessen suffering, disability, and dependence in old age. In this review, we summarise the healthy ageing scores reported in the literature, with a focus on the past 5 years, and compare and contrast the variables employed. The use of approaches to determine biological age, molecular biomarkers, ageing trajectories, and multi-omics ageing scores are reviewed. We conclude that the ideal healthy ageing score is multisystemic and able to encompass all of the potential alterations associated with ageing. It should also be longitudinal and able to accurately predict ageing complications at an early stage in order to maximize the chances of successful early intervention.