Search Results (82)

Understanding intraspecific functional trait variability (ITV) is crucial for elucidating plant functional strategies under environmental change. This study investigates the functional responses of 129 Mediterranean olive (Olea europaea L.) cultivars conserved in the Worldwide Olive Germplasm Bank of Marrakech (WOGBM), focusing on three key leaf traits: specific leaf area (SLA), specific leaf water content (SLWC), and leaf area (LA). Substantial ITV was observed, with variability predominantly driven by cultivar differences and geographic origin. LA accounted for the highest within-cultivar variability (43.60%), followed by SLWC (31.67%) and SLA (17.92%). Geographic origin significantly influenced trait expression, with eastern Mediterranean cultivars exhibiting conservative resource-use strategies (high SLWC, low SLA, and LA), while western cultivars displayed acquisitive strategies (high SLA and LA, low SLWC). Principal component analysis further differentiated eastern and western cultivars, reflecting biogeographical and evolutionary influences. The relationship between LA and climatic variables suggests climate-driven selection, where cultivars from wetter regions develop larger leaves to optimize light capture and carbon assimilation, whereas those from drier environments exhibit smaller leaves to reduce water loss. These findings highlight a trade-off between resource acquisition and conservation, supporting the leaf economic spectrum at the intraspecific level. This study underscores the importance of ITV in olive diversification and adaptation, providing insights for breeding, conservation, and climate resilience. A trait-based approach proves valuable for exploring domestication processes and plant responses to environmental gradients. Full article

The marine fish genus Trachinotus (Carangidae: Trachinotinae) comprises species of considerable economic and ecological importance; however, a significant gap in genomic data has limited the understanding of its evolutionary history and systematics. To address this gap, we determined the complete mitochondrial genomes of two key species, Trachinotus goodei (Palometa) and Trachinotus mookalee (Indian Pompano). The mitogenome of T. goodei was sequenced from genomic DNA and assembled de novo, whereas the T. mookalee mitogenome was assembled by mining publicly available RNA-Seq data, demonstrating a cost-effective approach for expanding genomic resources. The resulting mitogenomes were 16,547 bp and 16,545 bp long, respectively, and both presented conserved gene content (13 protein-coding genes, 22 tRNAs, 2 rRNAs) and organization typical of teleost fishes. Phylogenetic analysis incorporating these new genomes with those of four other Trachinotus species was performed via a concatenated dataset of 13 protein-coding genes. Maximum likelihood and Bayesian inference recovered Trachinotus as a strongly supported monophyletic group. The phylogeny revealed a fundamental and deeply divergent split between three major clades, two comprising species from the western Atlantic and the other containing species from the eastern Atlantic/Mediterranean/Indo-Pacific. This robust biogeographic partition provides compelling evidence that allopatric speciation is a primary driver of diversification within the genus. Full article

Background: Primary stability of dental implants depends on bone quality, bone quantity, and implant design. In cases of large defects, such as periapical lesions, the selection of an appropriate alveolar ridge preservation (ARP) material is crucial for bone regeneration and preparation for implant placement. Objective: The aim of this study was to evaluate clinical and histological outcomes of a novel ARP material hydroxyapatite and sugar cross-linked collagen (HSCC) combined with a knife-edge thread implant (KTI) design. Methods: Thirty patients were divided into two groups: a control group treated with KTI after spontaneous alveolar ridge healing, and an experimental group that underwent ARP using HSCC, and six months later, KTIs were placed in newly formed bone. Clinical parameters including insertion torque value (ITV), resonance frequency analysis (RFA), implant stability quotient (ISQ), and horizontal bone dimension were evaluated. Histological analysis was also performed. Results: No significant differences were observed between groups in ITV, ISQ, or horizontal bone dimension (p > 0.05). However, histological analysis demonstrated a significantly higher number of active osteoblasts in the ARP group compared to the control (p < 0.001), whereas collagen deposition was significantly greater in the control group (p < 0.001). Conclusions: ARP using HSCC, combined with KTI, provides favorable conditions for primary stability and successful graft integration, supporting reliable implant placement in sites with bone defects. Full article

Functional traits provide key insights into plant ecological strategies and responses to environmental heterogeneity, yet the role of intraspecific trait variability (ITV) in tropical rainforests remains underexplored. We examined ITV in six leaf traits—leaf thickness (LT), leaf area (LA), specific leaf area (SLA), leaf dry matter content (LDMC), leaf nitrogen content (LNC), and stomatal density (SD)—in saplings of 15 dominant tree species across ridge and valley habitats in a Sri Lankan tropical lowland rainforest. We compared interspecific and intraspecific variation and quantified trait plasticity using the plasticity index. Significant ITV was observed for LT, LA, and SD, with ridge individuals showing smaller, thicker leaves with lower SD. SLA, LDMC, and LNC exhibited no overall habitat-level differences, though species-specific divergent responses were detected. Interspecific variation exceeded ITV for most traits, except for LNC, where ITV accounted for 55% of total variation. Trait plasticity varied among traits, with LNC showing the highest plasticity. These results indicate that individuals adjust leaf traits in response to fine-scale habitat heterogeneity, reflecting shifts in resource-use strategies. Overall, ITV is ecologically meaningful and should be incorporated into community-level studies and ecosystem models to improve predictions of plant community dynamics and ecosystem functioning under environmental change. Full article

Biological invasions provide a unique window into community assembly. While classic theory predicts that native species must differentiate their niches to coexist with an invader, the actual outcomes under intense pressure are complex. Our study examines community reassembly under extreme pressure from the invasive ant Solenopsis invicta. We found that while native species do differentiate themselves from the invader, the overwhelming competition constrains this process, forcing survivors into a narrow, shared functional space. This constrained niche differentiation produces a pattern of community-level functional convergence, a process where functionally dissimilar communities become more similar under intense environmental filtering, as survivors are forced into a narrow, shared niche space. The capacity for these rapid, adaptive niche shifts is rooted in intraspecific trait variation (ITV). We also identified a dynamic feedback loop through density-dependent phenotypic plasticity in the invader. By showing how the foundational process of niche differentiation leads to a convergent outcome under extreme pressure, our work clarifies the rules of community assembly in an increasingly invaded world. Full article

Processing economically and socio-culturally significant Amazonian fruits—andiroba (Carapa guianensis Aubl.), açai (Euterpe oleracea Mart.), and babassu (Attalea speciosa Mart. ex Spreng.)—generates substantial biomass waste, posing critical environmental and waste management challenges. This study explored the valorization of these abundant residual biomasses as sustainable feedstocks for biosurfactant production by bacterium Pseudomonas aeruginosa P23G-02, while simultaneously profiling their nutritional value and broader implications for a circular bioeconomy. Through liquid fermentation, biosurfactants were produced at an approximate yield of 6 mg/mL. The isolated biosurfactants exhibited favorable properties, including emulsification indices of around 60% and surface tension reduction to below 30 mN/m, with the andiroba-derived biosurfactant identified as a rhamnolipid type. Nutritional profiling of the residues revealed significant energy values, reaching up to 656 kcal/100 g, with açai and babassu residues being carbohydrate-rich (exceeding 80%), and andiroba residues exhibiting a high lipid profile (up to 57%). These distinct compositions critically influenced biosurfactant yield. These findings underscore the viability of Amazonian fruit biomass as valuable resources for developing eco-friendly bioproducts and innovative waste management solutions. While highlighting a promising pathway for circular bioeconomy development, future research should address biosafety and explore alternative microbial hosts for applications in sensitive sectors such as food and nutrition. Full article

Plant functional traits (PFTs) serve as key predictors of plant survival and adaptation to environmental gradients. Studies on intraspecific variation in PFTs are crucial for evaluating species’ adaptation to projected climate change and developing long-term conservation strategies. This study systematically investigated PFT responses in Polyspora chrysandra (Theaceae, Yunnan, China) through an integrated multivariate analysis of 20 leaf functional traits (LFTs) and 33 environmental factors categorized into geographical conditions (GCs), climate factors (CFs), soil properties (SPs), and ultraviolet radiation factors (UVRFs). To disentangle complex environmental–trait relationships, we employed redundancy analysis (RDA), hierarchical partitioning (HP), and partial least squares structural equation modeling (PLS-SEM) to assess direct, indirect, and latent relationships. Results showed that the intraspecific coefficient of variation (CV) ranged from 7.071% to 25.650%. Leaf tissue density (LTD), specific leaf area (SLA), leaf fresh weight (LFW), leaf dry weight (LDW), and leaf area (LA) exhibited moderate intraspecific trait variation (ITV), while all other traits demonstrated low ITV. Reference Bulk density (RBD) and Silt emerged as significant factors driving the variation. Latitude (Lat), altitude (Alt), and mean warmest month temperature (MWMT) were also identified as key influences. HP analysis revealed Silt as the most important predictor (p < 0.05). Latent variable analysis indicated descending contribution rates: SPs (31.51%) > GCs (11.52%) > CFs (11.04%) > UVRFs (10.29%). Co-effect analysis highlighted significant coupling effects involving RBD and cation exchange capacity of clay (CECC), as well as organic carbon content (OCC) and UV-B seasonality (UVB2). Path analysis showed SPs as having the strongest influence on leaf thickness (LT), followed by GCs and UVRFs. These findings provide empirical insights into the biogeographical patterns of ITV in P. chrysandra, enhance the understanding of plant environmental adaptation mechanisms, and offer a theoretical foundation for studying community assembly and ecosystem function maintenance. Full article

This study aimed to characterize students from the Instituto Tecnológico del Valle de Etla (ITVE), located in Oaxaca, Mexico, within the virtual learning environment (VLE) and to identify the main technological challenges affecting their learning experience. The research adopted a descriptive quantitative approach, using a self-administered questionnaire applied to a sample of 71 students enrolled in distance education programs. The instrument made it possible to analyze variables such as online instructional design, teaching experience, and information technologies. The results evidenced four distinct student profiles identified as follows: demanding, digitally competent, dependent on didactic material, and with technological barriers. These profiles reflect disparities in connectivity conditions, digital competencies, and expectations toward instructional design. The evidence generated by this research contributes to the formulation of more inclusive and resilient educational policies, in line with Sustainable Development Goal 4 (SDG 4), which promotes inclusive, equitable, and quality education for all. Full article

The present study characterizes the complete mitochondrial genome of Potamotrygon leopoldi, commonly referred to as the “white blotched stingray”, a member of the Potamotrygonidae family that are a group of stingrays that live exclusively in freshwater environments. Potamotrygon leopoldi, endemic to the Xingu River in the Amazon region, are exploited by commercial fisheries for food and commonly exploited by the ornamental industry, and this has a significant impact on the populations. Here, newly assembled PacBio long-read sequencing assesses the complete mitogenome of P. leopoldi and performs a comparative investigation into the evolutionary connections to other extant taxa of elasmobranchs. The mitogenome has 17,504 bp, containing 13 protein-coding, 22 tRNA, and 2 rRNA genes. The mitogenome comprises A: 32.32%, T: 24.41%, C: 12.84%, and G: 30.42%, with an AT content of 56.73%. The values of AT and GC skewness were 0.13 and −0.40, respectively. Our phylogenetic analyses with mitogenome sequences of 40 elasmobranch species support the monophyly for the Potamotrygonidae family and indicate a close relationship to the Dasyatidae family and a sister relationship with Potamotrygon orbignyi and Potamotrygon falkneri. We also detected various amino acid sites in positive selection exclusively in P. leopoldi. This extensive comparative mitogenomic investigation offers novel and significant insights into the evolutionary lineage of neotropical freshwater stingrays and their closely related taxa. It is an indispensable resource for facilitating ongoing and prospective investigations into the molecular evolution of elasmobranchs. Full article

Lightning nowcasting is crucial for ensuring safety and operational continuity in weather-exposed industries such as mining. This study evaluates three machine learning (ML)-based approaches for predicting lightning using dual-polarimetric weather radar data collected in the eastern Amazon, Brazil. The strategies propose advances in literature in three ways by involving (i) grouping radar variables by temperature layers, (ii) statistical summaries at key altitudes, and (iii) analyzing all the 18 levels of reflectivity data combined with Principal Component Analysis (PCA) dimensionality reduction and ensemble models. For each approach, models such as Random Forest, Support Vector Machines, and XGBoost were trained and tested using data from 2021–2022 with class balancing and feature engineering techniques. Among the approaches, the PCA-based ensemble achieved the best generalization (recall = 0.89, F1 = 0.77), while the layer-based method had the highest recall (0.97), and the altitude-based strategy offered a computationally efficient alternative with competitive results. These findings confirm the predictive value of radar-derived features and emphasize the role of feature representation in model performance. Additionally, the best model was integrated into the operational LEWAIS alert system, and four integration strategies were tested. The strategy that combined alerts from both ML and LEWAIS systems reduced the failure-to-warn rate to 0.0531 and increased the lead time to 10.18 min, making it ideal for safety-critical applications. Overall, the results show that ML models based solely on radar inputs can achieve robust lightning nowcasting, supporting both scientific advancement and industrial risk mitigation. Full article

Water-use efficiency (WUE) plays a crucial role in sustainable crop production, particularly in water-limited environments where maximizing natural resource use is essential. This study evaluated the physiological and agronomic performance of two Piper nigrum cultivars, Clonada and Uthirankotta, grown under different soil water potential conditions. The trial was conducted in a 1930 m² field using a randomized block design and drip irrigation system, calibrated to 3.55 L h⁻¹ with a uniformity of 97%. Soil water availability was managed based on daily tensiometer readings at 20 and 30 cm depths, triggering irrigation at defined tensions (10–55 kPa). Clonada exhibited higher net CO₂ assimilation rates (A) and stomatal conductance (g_s), but these responses did not lead to higher yields. In contrast, Uthirankotta consistently maintained superior water-use efficiency and yield across all soil moisture conditions by favoring water conservation and targeted biomass allocation over maximized gas exchange. Both cultivars performed optimally at a soil water potential range of 25–35 kPa, with declines in yield and gas exchange parameters at higher tensions (45–55 kPa). Under such conditions, Uthirankotta was 51.3% more water-use efficient and 40.8% more productive than Clonada. Based on this, a Principal Component Analysis (PCA) further demonstrated distinct physiological profiles, underscoring trade-offs between yield and water-use strategies. These results highlight the significance of cultivar selection for optimizing WUE and provide valuable insights into irrigation management and breeding programs aimed at boosting black pepper performance under water-limited conditions. Full article

Stephanopodium engleri Baill. is an endangered tree species from the Dichapetalaceae family and endemic to the Iron Quadrangle region of Brazil. Recalcitrance and low seed viability limit conventional seedling production, making vegetative propagation a crucial alternative for conservation efforts. This study evaluated the rooting and sprouting potential of different cutting types (apical, middle, and basal segments from the main stem, as well as the tip and the herbaceous and woody segments from the lateral branches) treated with Indole-3-Butyric Acid (IBA) at varying concentrations (0, 1, 2, 3, and 4 g L⁻¹) and immersion durations (5 s to 10 min). Cuttings were collected from 12-month-old plants grown under controlled conditions and planted in Carolina Soil^® substrate after treatment. Sprouting and rooting rates varied significantly between cutting types, with basal main stem cuttings showing the highest rooting success, particularly at 3 g L⁻¹ of IBA. These cuttings also exhibited more and longer roots and enhanced sprouting-related biometric traits. Shorter immersion times (15 s and 1 min) were the most effective, promoting root formation while avoiding the potential inhibitory effects of prolonged exposure. Our findings provide a practical protocol for large-scale seedling production of S. engleri while minimizing impacts on wild populations. The effective use of vegetative propagation could facilitate the expansion of S. engleri populations in their natural habitats, enhancing conservation efforts and ensuring sustainable species management. Full article

Lightning strikes are a major hazard in tropical regions, especially in northern Brazil, where open-area industries such as mining are highly exposed. This study proposes an octant-based multi-objective optimization approach for spatial lightning alert systems, focusing on minimizing both false alarm rate (FAR) and failure-to-warn (FTW). The method uses NSGA-III to optimize a configuration vector consisting of directional radii and alert thresholds, based solely on historical lightning location data. Experiments were conducted using four years of cloud-to-ground lightning data from a mining area in Pará, Brazil. Fifteen independent runs were executed, each with 96 individuals and up to 150 generations. The results showed a clear trade-off between FAR and FTW, with optimal solutions achieving up to 16% reduction in FAR and 50% reduction in FTW when compared to a quadrant-based baseline. The use of the hypervolume metric confirmed consistent convergence across runs. Sensitivity analysis revealed spatial patterns in optimal configurations, supporting the use of directional tuning. The proposed approach provides a flexible and interpretable model for risk-based alert strategies, compliant with safety regulations such as NBR 5419/2015 and NR-22. It offers a viable solution for automated alert generation in high-risk environments, especially where detailed meteorological data is unavailable. Full article

Achieving the appropriate primary stability for immediate or early loading in areas with low-density bone, such as the posterior maxilla, is challenging. A three-dimensional (3D) stabilization implant design featuring a tapered body with continuous cutting flutes along the length of the external thread form, with a combination of curved and linear geometric surfaces on the thread’s crest, has the capacity to enhance early biomechanical and osseointegration outcomes compared to implants with traditional buttressed thread profiles. Commercially available implants with a buttress thread design (TP), and an experimental implant that incorporated the 3D stabilization trimmed-thread design (TP 3DS) were used in this study. Six osteotomies were surgically created in the ilium of adult sheep (N = 14). Osteotomy sites were randomized to receive either the TP or TP 3DS implant to reduce site bias. Subjects were allowed to heal for either 3 or 12 weeks (N = 7 sheep/time point), after which samples were collected en bloc (including the implants and surrounding bone) and implants were either subjected to bench-top biomechanical testing (e.g., lateral loading), histological/histomorphometric analysis, or nanoindentation testing. Both implant designs yielded high insertion torque (ITV ≥ 30 N⋅cm) and implant stability quotient (ISQ ≥ 70) values, indicative of high primary stability. Qualitative histomorphological analysis revealed that the TP 3DS group exhibited a continuous bone–implant interface along the threaded region, in contrast to the TP group at the early, 3-week, healing time point. Furthermore, TP 3DS’s cutting flutes along the entire length of the implant permitted the distribution of autologous bone chips within the healing chambers. Histological evaluation at 12 weeks revealed an increase in woven bone containing a greater presence of lacunae within the healing chambers in both groups, consistent with an intramembranous-like healing pattern and absence of bone dieback. The TP 3DS macrogeometry yielded a ~66% increase in average lateral load during pushout testing at baseline (T = 0 weeks, p = 0.036) and significantly higher bone-to-implant contact (BIC) values at 3 weeks post-implantation (p = 0.006), relative to the traditional TP implant. In a low-density (Type IV) bone model, the TP 3DS implant demonstrated improved performance compared to the conventional TP, as evidenced by an increase in baseline lateral loading capacity and increased BIC during the early stages of osseointegration. These findings indicate that the modified implant configuration of the TP 3DS facilitates more favorable biomechanical integration and may promote more rapid and stable bone anchorage under compromised bone quality conditions. Therefore, such improvements could have important clinical implications for the success and longevity of dental implants placed in regions with low bone density. Full article

Background: The re-irradiation of centrally located lung tumors poses substantial risks due to prior dose exposure and proximity to critical structures. Accurate target delineation is crucial to minimize toxicity and ensure tumor coverage. Four-dimensional positron emission tomography/computed tomography (4D-PET/CT) integrates respiratory motion and metabolic data, offering improved delineation over static imaging. Its clinical utility in re-irradiation remains under-reported. Methods: A 67-year-old male presented with the central recurrence of squamous cell carcinoma in the right upper lobe, embedded in radiation-induced fibrosis, following prior chemoradiotherapy. Delineation using static PET underestimated tumor motion. A 4D-PET/CT-guided Stereotactic Body Radiation Therapy (SBRT) plan was developed with a prescription of 60 Gy in eight fractions. A comparative plan using static PET was generated to assess the dosimetric differences. Results: The internal target volume (ITV) from 4D-PET/CT was nearly double the size of the GTV from static PET, with a 5.1 mm discrepancy in the craniocaudal axis. The 4D-PET-based plan achieved 95.0% PTV coverage, while the static PET-based plan covered only 61.7%, illustrating the risk of underdosage without motion-resolved imaging. The patient completed the treatment without acute or late toxicity and showed a sustained metabolic response at one year (SUVmax from 13.4 to 5.8). Conclusions: This case demonstrates the clinical value of 4D-PET/CT in the SBRT re-irradiation of centrally located lung tumors, particularly in fibrotic regions where anatomical imaging is insufficient. It enabled accurate delineation, improved dosimetric coverage, and safe, effective retreatment. These findings support its integration into planning for complex thoracic re-irradiation. Full article