In the context of the Anthropocene, Mediterranean aquifer systems are increasingly threatened by climate variability, population growth, and unsustainable groundwater extraction, driving groundwater depletion and salinization across the region. Within this framework, the Grombalia Plain in northeastern Tunisia represents a critical hotspot, where an aquifer system overused by more than 400
Soil organic carbon (SOC) in agricultural soils is a cornerstone of soil health and climate change mitigation, and its accumulation is largely dependent on composition and addition rates of plant residues. Our objectives were to determine the stabilization pathways of SOC derived from root and shoot residues of different plant species and to assess the impact of shoot input rates on these pathways. We cultivated in pots three species selected for their different C:N ratios-wheat (Tricitum aestivum), crimson clover (Trifolium incarnatum) and pea (Pisum sativum) - and exposed to weekly 13CO2 pulse labeling until the flowering stage. At harvest, shoot and root were collected for biochemical and morphological characterization, and 13C tracing in soil was used to estimate rhizodeposition-derived C. To assess the contributions of root and shoot degradation to SOC, pots containing soil and intact root systems, and soil amended with different shoot residues rates (1, 2, or 6 Mg C ha-1) were incubated under controlled conditions for 2 and 12 months. Soils incubated with shoot and root residues were particle size fractionated into particulate organic matter (POM), and mineral-associated organic matter (MAOM) consisting of fine silt and clay fractions. A greater amount of SOC was derived from rhizodeposition and root degradation by wheat (0.58 and 0.70 g kg-1, respectively) than legumes (0.22 and 0.001 g kg-1, respectively). On the other hand, a greater contribution of legume- than wheat- shoot residues was observed to SOC (0.71 vs. 0.29 g kg-1) and to clay-C fraction (0.90 vs. 0.63 g kg-1), particularly at 2 and 6 Mg C ha-1. The high content of recalcitrant compounds such as hemicellulose and cellulose of wheat roots explains the strong contribution to SOC and their preferential accumulation in POM. Conversely, the preferential contribution of legume shoots to MAOM is likely due to the higher water-soluble compounds and N contents. Our results suggest that both grasses and legumes can enhance SOC content by targeting different organic matter pools. Similar studies conducted in the field could contribute to emphasize the role of plant-specific residue composition in shaping C stabilization pathways in the soil.
In this study, a sustainable calcium-rich biochar was synthesized via co-pyrolysis at 800 degrees C of marble waste, animal manure, and lignocellulosic biomass. This biochar (MWM-B) was comprehensively characterized and then valorized for phosphorus (P) removal from real effluent and synthetic solutions in both batch and continuous stirred tank reactor (CSTR) modes. Characterization results confirm the formation and deposition of significant amounts of calcium oxides and calcium hydroxides on the biochar surface, which enhance the biochar's surface chemistry and textural properties. In batch mode, MWM-B efficiently removes P with a removal capacity (108.4 mg g-1) that is 5.3 times higher than that observed in the CSTR system. This efficiency drop is due to the limited contact time between phosphate species and the biochar particles. Interestingly, the presence of calcium and magnesium in the continuously renewed real effluent in the CSTR system increases P removal efficiency by approximately 136% compared with synthetic solutions. A detailed analysis of MWM-B before and after P removal suggests that this process occurs mainly through precipitation as hydroxyapatite, complexation with hydroxyl functional groups, electrostatic interactions, and hydrogen bonding. This work confirms that MWM-B generated at 800 degrees C is an attractive material for P removal from effluents.
Recreational aquatic activities carry a significant risk of injury and fatality, with drowning being the primary cause of death. Although encounters with aquatic wildlife are usually accidental, they can occasionally result in severe stings or bites. Here, we present the case of a man in his early thirties who suddenly disappeared while swimming with seven others in the Gulf of Aden, just ten minutes after entering the water. Despite extensive search efforts, he could not be located. His body was recovered on the shore forty-eight hours later. The autopsy revealed a large, irregular, semicircular wound of 42 cm in diameter, with distinct bite marks on the right side of the torso, strongly suggestive of a shark attack. However, no shark tooth fragments were recovered during the examination. No evidence of drowning or myocardial infarction was identified. The wound margins exhibited haemorrhagic infiltration, indicating vital tissue reaction. Although the probability of a shark attack is minimal compared with other causes of injury and death in such environments, the findings in this case were compelling. This article examines the evidence supporting a fatal shark attack, as opposed to postmortem scavenging of a victim who died from alternative causes, and presents the forensic arguments and indicators that led to the identification of the responsible species, the tiger shark (Galeocerdo cuvier). Rare fatal shark attack documented in the Gulf of Aden. Autopsy findings revealed characteristic features of a large shark bite. Forensic analysis of the wound suggested a tiger shark (Galeocerdo cuvier).
A expansão da Inteligência Artificial (IA) no campo educacional tem impulsionado o desenvolvimento de sistemas, plataformas, ambientes adaptativos e outros artefatos capazes de apoiar processos de ensino, aprendizagem, gestão e produção do conhecimento. Entretanto, a incorporação de funcionalidades inteligentes, por si só, não assegura relevância educacional, rigor científico ou adequação ética das soluções produzidas. Nesse cenário, o Design Science Research (DSR) apresenta-se como uma abordagem particularmente pertinente por articular a identificação de problemas reais, a construção de artefatos, sua avaliação sistemática e a produção de conhecimento científico decorrente do processo de design. Este artigo tem como objetivo sistematizar princípios teórico-metodológicos capazes de orientar o desenvolvimento e a avaliação de artefatos educacionais inteligentes fundamentados na articulação entre DSR e IA. Metodologicamente, caracteriza-se como um estudo qualitativo, de natureza teórico-bibliográfica e documental, construído a partir da análise de produções sobre Design Science, DSR, tecnologias educacionais e Inteligência Artificial na Educação, estabelecendo também diálogo analítico com uma experiência anterior de pesquisa aplicada desenvolvida no âmbito da pós-graduação. Como resultado da articulação teórica, são propostos oito princípios: relevância contextual; rigor teórico-metodológico; intencionalidade educacional; participação dos usuários e iteratividade; integração interdisciplinar; avaliação multidimensional; ética, transparência e governança de dados; e documentação, aprendizagem e evolução contínua. Defende-se que artefatos educacionais inteligentes não devem ser avaliados apenas pelo desempenho técnico, mas por sua capacidade de responder a problemas educacionais concretos, produzir valor pedagógico e institucional e preservar a centralidade humana nos processos mediados por IA. Conclui-se que a aproximação entre DSR e IA amplia as possibilidades de uma pesquisa educacional simultaneamente projetual, científica, crítica e comprometida com a transformação responsável das práticas educacionais.
