Browsing by Issue Date, starting with "2022-07"
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- Southern African Stone Age archaeology and palaeontology in a mining context: the example of Gudrun Corvinus in the diamond mines of the Sperrgebiet, Namibia (1976–1980)Publication . Mesfin, Isis; Mussgnug, Ulla; Hallinan, EmilyMining operations in Africa have played a considerable role in the reconstruction of human evolution. These contributions would not have been possible without co-operation between the mining industry, archaeology and palaeontology. However, closer scrutiny of their initially fortuitous relationship reveals limitations and fundamental differences in approach. A compelling case study is that of palaeontologist and archaeologist Gudrun Corvinus, employed by Consolidated Diamond Mines in the Sperrgebiet region of Namibia between 1976 and 1980. Corvinus wrote numerous internal mine reports and scientific publications, but also left behind an exhaustive body of private records along with palaeontological and archaeological museum collections. By contrasting this legacy, this paper presents a rich narrative of her attempt to reconcile the fulfilment of her contract requirements with her scientific principles. It sketches a progressively conflict-laden relationship between her and the profit-centred management of a multi-national company. The scientific legacy of Gudrun Corvinus and the historiographical facts and ramifications of this loss of co-operation are discussed in terms of cultural heritage, scientific knowledge and dissemination. Assessing her fight in the naturally and culturally rich environment of the Sperrgebiet, the paper concludes by considering the threat that mining poses to Pleistocene heritage sites in Namibia.
- Distribution, identification and cytotoxicity of Gambierdiscus (Dinophyceae) in the Atlantic Selvagens Islands (Madeira, Portugal): a ciguatera gateway to EuropePublication . Godinho, Lia; Soliño, Lucia; Churro, Catarina; Timoteo, Viriato; Santos, Carolina; Gouveia, Neide; Diogène, Jorge; Reis Costa, PedroThe emerging threat of ciguatera poisoning (CP) in Europe has been associated with fish captured in the Canary Islands (Spain) and Selvagens Islands (Portugal). The first are heavily populated islands where numerous scientific studies have been carried out. Conversely, the Selvagens Islands are a nature reserve with low human pressure that have been rarely surveyed in terms of the marine benthic microalgae, including the epiphytic ciguatera-causing dinoflagellate species. To investigate the harmful microalgal diversity of the Selvagens Islands, a scientific cruise to these remote islands took place in September, 2018. The Gambierdiscus species composition and distribution, and the associated epiphytic dinoflagellate community, were assessed using artificial substrate devices. Gambierdiscus cells were found in all samples, reaching concentrations of up to 725 cells 100 cm(-2). G. australes was the only species identified after morphological and molecular analysis of the retrieved cultures. Species identification was confirmed by molecular characterization based on the LSU D8-D10 region. Nevertheless, phylogenetic studies indicated that some strains diverged from the G. australes clade suggesting genetic differentiation. Toxicity was estimated by neuro-2a cell-based assay in four strains, ranging from 2.46-83 fg of CTX1B eq. cell(-1). The epiphytic dinoflagellate community that co-occurred with Gambierdiscus comprised other toxic or potentially toxic dinoflagellates, such as Ostreopsis, Prorocentrum, Amphidinium and Coolia species. Oceanographic and meteorological data were also obtained to characterize the occurrence of Gambierdiscus. This study is the first stage in understanding the role of the Selvagens Islands in the incubation and proliferation of the ciguatera-causing dinoflagellates Gambierdiscus in the NE Atlantic.
- A deep learning approach to improving spectral analysis of fruit quality under interseason variationPublication . Yang, Jie; Luo, Xuan; Zhang, Xiaolei; Passos, Dário; Xie, Lijuan; Rao, Xiuqin; Xu, Huirong; Ting, K.C.; Lin, Tao; Ying, YibinModel updating for developed calibrations is critical for robust spectral analysis in fruit quality control. Existing methods have limitations that usually need sufficient samples for model recalibration and are mainly designed for conventional linear models. This study proposes a model fine-tuning approach to update nonlinear deep learning models using limited sample sizes for fruit detection under interseason variation. This approach provides RMSE of 0.407, 1.035, and 0.642, for predicting soluble solid content (%) or dry matter content (%), in the Cuiguan pear, Rocha pear, and Mango dataset. The proposed approach reduces at least 9.2%, 17.5%, and 11.6% of test RMSE in three datasets compared with conventional model updating methods, including the global model, recalibration, and slope/bias correction. The model fine-tuning approach shows improved reliability under different updating sample sizes, ranging from 5% to 20% proportions of the new season's samples. The utilization of cumulative data in multiple previous seasons enables further improved performance. This study potentially facilitates implementing high-performance deep learning approaches in on-site applications of fruit quality control.
- Temporal shifts in ostracode sexual dimorphism from the Late Cretaceous to the late Eocene of the U.S. Coastal PlainPublication . Samuels-Fair, Maya; Martins, Maria Joao Fernandes; Lockwood, Rowan; Swaddle, John P.; Hunt, GeneOstracodes of the superfamily Cytheroidea exhibit sexual dimorphism in the carapace such that males are more elongate than females. This sex difference is attributed to the need of the carapace to accommodate the large male copulatory apparatus, and the degree of dimorphism is an indication of male investment in reproduction. In this study, we examine trends in sexual dimorphism, as a proxy for sexual selection, from the Late Cretaceous to the late Eocene to better understand the long-term effects of the Cretaceous/Paleogene mass extinction. We used mixture models to identify sex clusters from digitized outlines of photographed specimens and estimated size and shape dimorphism as the difference in the mean log area and the mean log length-to-height ratio for male and female clusters. We found dimorphism exhibits a phylogenetic signal; families and genera tend to occupy various restricted subsets of dimorphism space. Previous work documented that the mean and variance in size and shape dimorphism decreased sharply at the Cretaceous/Paleogene boundary, and here we show that this fauna only partially returns to Cretaceous dimorphism patterns by the late Eocene. Most surprisingly, species with both high size and shape dimorphism, which occurred in a diverse set of taxa before the extinction, remain rare into the late Eocene. These trends suggest sexual selection may respond to several possible demographic and environmental factors, which warrant further investigation.
- Memorial do Convento e a conquista da notoriedade pelo escritor José SaramagoPublication . Carmo, Carina Infante doNuma resposta dada em entrevista a Carlos Payás, em 2006, José Saramago invoca o impacto que teve na sua trajetória a exoneração do cargo de director- adjunto do Jornal de Notícias, em novembro de 1975, levando-o a um decisivo salto no escuro que foi procurar ser escritor.
- The multi-annual residency of juvenile smooth hammerhead shark in an oceanic island nurseryPublication . Afonso, Pedro; Gandra, Miguel; Graça, Gonçalo; Macena, Bruno; Vandeperre, Frederic; Fontes, JorgeThe increased risk of local extinction becomes critical for sharks depending on the narrow and isolated coastal habitats of oceanic islands. This includes large pelagic oceanic sharks that use such habitats as nurseries, as previously hypothesized for the smooth hammerhead Sphyrna zygaena, the least known of cosmopolitan large hammerhead sharks. We used a combination of acoustic and satellite telemetry in a juvenile population of Faial and Pico islands, Azores, mid-north Atlantic, to confirm if this isolated archipelago holds nurseries, and to answer questions related to their function and spatial-temporal stability. Our long-term acoustic tracking data showed a cluster of individual core home ranges in specific areas of north shore Faial, and surface positions from five Argos-linked tagged individuals also showed a clustering overlap in those areas for up to 1 year. These patterns seem to reveal a true habitat preference within the Faial-Pico island (sub) population of juvenile smooth hammerhead shark, and thus constitute strong evidence for this area to be considered a nursery. Some individuals remained in this nursery for up to 4 years, especially during summers. Sharks also showed a strong diel behavior, typically using the inshore nurseries during the day and moving further offshore during the night, during which they increased activity and dove deeper, most possibly to feed. We speculate that a combination of increased feeding opportunities, expanded trophic niche, and reduced predatory pressure may be a key evolutionary driver for the existence, prolonged use, and even preference of coastal nurseries at oceanic islands by juvenile smooth hammerhead shark. Given that these nurseries may constitute essential fish habitat for this species, they should be explicitly included in spatial management measures at the local and regional scales, as they may also play a role of greater importance to the north Atlantic population of this oceanic species.
- Attention-based model and deep reinforcement learning for distribution of event processing tasksPublication . Mazayev, Andriy; Al-Tam, Faroq; Correia, NoéliaEvent processing is the cornerstone of the dynamic and responsive Internet of Things (IoT). Recent approaches in this area are based on representational state transfer (REST) principles, which allow event processing tasks to be placed at any device that follows the same principles. However, the tasks should be properly distributed among edge devices to ensure fair resources utilization and guarantee seamless execution. This article investigates the use of deep learning to fairly distribute the tasks. An attention-based neural network model is proposed to generate efficient load balancing solutions under different scenarios. The proposed model is based on the Transformer and Pointer Network architectures, and is trained by an advantage actorcritic reinforcement learning algorithm. The model is designed to scale to the number of event processing tasks and the number of edge devices, with no need for hyperparameters re-tuning or even retraining. Extensive experimental results show that the proposed model outperforms conventional heuristics in many key performance indicators. The generic design and the obtained results show that the proposed model can potentially be applied to several other load balancing problem variations, which makes the proposal an attractive option to be used in real-world scenarios due to its scalability and efficiency.
- Clear cell neoplasms of salivary glands: A diagnostic challengePublication . Skalova, Alena; Leivo, Ilmo; Hellquist, Henrik; Simpson, Roderick H.W.; Vander Poorten, Vincent; Willems, Stefan M.; Mosaieby, Elaheh; Slouka, David; Ferlito, AlfioThis review focuses on the heterogenous group of clear cell neoplasms of salivary glands and attempts to identify major differential diagnostic features. Within the head and neck region, clear cells are found most commonly in salivary gland tumors, but may also be seen in tumors of squamous or odontogenic epithelial origin, primary or metastatic carcinomas, benign or malignant melanocytic lesions, or benign or malignant mesenchymal tumors. Clear cells occur fairly commonly among a wide variety of salivary gland neoplasms, but mostly they constitute only a minor component of the tumor cell population. Clear cells represent a major diagnostic feature in two salivary gland neoplasms, epithelial-myoepithelial carcinoma and hyalinizing clear cell carcinoma. In addition, salivary gland neoplasms composed predominantly of clear cells could also include clear cell variants of other salivary neoplasms, such as mucoepidermoid carcinoma and myoepithelial carcinoma, but their tumor type-specific histologic features may only be available in limited nonclear cell areas of the tumor. Diagnosing predominantly clear cell salivary gland tumors is difficult because the immunoprofiles and morphologic features may overlap and the same tumor entity may also have a wide range of other histologic presentations. Many salivary gland tumors are characterized by tumor type-specific genomic alterations, particularly gene fusions of the ETV6 gene in secretory carcinoma, the MYB and MYBL1 genes in adenoid cystic carcinoma, the MAML2 gene in mucoepidermoid carcinoma, the EWSR1 gene in hyalinizing clear cell carcinoma, and others. Thus, along with conventional histopathologic examination and immunoprofiling, molecular and genetic tests may be important in the diagnosis of salivary gland clear cell tumors by demonstrating genetic alterations specific to them.
- Left ventricular non-compaction: challenges in the etiopathogenesis and risk stratification of sudden cardiac death in clinical practicePublication . Marques, NunoIn their study published in this issue of the Journal,1 Oliveira et al. elegantly described a family of patients with left ventricular non-compaction (LVNC), illustrating the challenges in clinical practice regarding etiological investigation and risk stratification of sudden cardiac death in these patients. A family history of LVNC has been described in about 30% of cases2 and a pathogenic mutation has been found in nearly one-third.3 Although LVNC is a genetically heterogeneous cardiomyopathy, sarcomere mutations represent more than half of the known genetic causes, especially in adults, and MYH7 is one of the most commonly mutated genes.2 Nevertheless, the causal relation between genetic variants and the LVNC phenotype remains to be ascertained in the majority of cases. This case report underlines the importance of a specialized cardiomyopathy team in the systematic genetic and clinical screening of family relatives and the interpretation of the clinical significance of genetic variants in LVNC.
- Concentrating solar cookers in urban areas: establishing usefulness through realistic intermediate temperature rating and gradingPublication . Sagade, Atul A.; Apaolaza-Pagoaga, Xabier; Ruivo, Celestino; Carrillo-Andrés, AntonioConcentrating Solar Cookers (CSCs) are well-known for fast cooking and can significantly contribute to attaining the United Nation's sustainable development goals. CSCs attain intermediate temperatures (120-240 degrees C) and are suitable for several cooking applications. The realistic rating and grading of CSCs is inevitable for establishing their usefulness in urban areas, which is the main objective of the present work. This paper reveals the experimental results of two existing concentrating solar cookers with different geometries and aperture areas. The first cooker is a shallow satellite antenna parabolic dish, and the other is a small deep parabola. Cooker Opto-thermal Ratio (COR) acts as a thermal performance parameter, and glycerin as a test load for their performance evaluation.The mean values of COR for the cookers, CSC1, and CSC3, are 0.180 and 0.092, respectively. The typical theoretical values of maximum achievable fluid temperature are 192.9 and 113.9 degrees C, respectively, and that for reference time are 23.8 and 60.5 min for CSC1 and CSC3, respectively. COR identifies the variation in the performance of CSCs based on a design change. The objective parameters enable realistic intra-cooker performance comparison of the CSCs at intermediate temperatures. The results depict that the existing designs of CSCs can be graded appropriately using COR and provide new insights into their performance at intermediate temperatures realistically. TPP-based realistic rating and grading of existing designs of solar cookers enable their effortless selection as per end-user requirements and help in the faster propagation of solar cooking technology in urban and semi-urban areas.