Search Results (197)

Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) represents a major advancement in remote sensing for terrestrial observation, substantially improving the capability to map vegetation structural parameters. However, spatial heterogeneity poses significant challenges to data accuracy. To evaluate the performance of ICESat-2 and improve its inversion accuracy, this study used airborne LiDAR data to validate ICESat-2 terrain and canopy height measurements in boreal forests of Alberta, Canada, and in three tropical rainforest regions—Costa Rica, French Guiana, and Gabon. Machine-learning approaches were further applied to calibrate ICESat-2 canopy height estimates. Our results show that the uncalibrated ICESat-2 data exhibit strong consistency in boreal forests, with higher accuracy under snow-covered nighttime conditions (terrain error < 1 m, canopy height error of 3.19 m). In contrast, the uncertainties in tropical rainforests are considerably larger, with terrain errors of 3–7 m and canopy height errors of 5–7 m. After calibration, XGBoost reduced canopy height error by 0.84 m in boreal forests, whereas Random Forest calibration improved canopy height accuracy by 1.09 m in tropical regions. Overall, our findings provide additional scientific evidence supporting the reliability of ICESat-2 measurements and substantially enhance the accuracy of satellite-based canopy height estimation. Full article

The present study has applied a probabilistic oil spill modeling framework to assess the potential risks associated with offshore oil spills in the Foz do Amazonas sedimentary basin, a region of exceptional ecological importance and increasing geopolitical and socio-environmental relevance. By integrating a large ensemble of simulations with validated hydrodynamic, atmospheric and wave-driven forcings, the analysis of said simulations has provided a robust and seasonally resolved assessment of oil drift and beaching patterns along the Guianas and the Brazilian Equatorial Margin. The model has presented a total of 47,500 simulations performed on 95 drilling sites located across the basin, using the Lagrangian Spill, Transport and Fate Model (STFM) and incorporating a six-year oceanographic and meteorological variability. The simulations have included ocean current fields provided by HYCOM, wind forcing provided by GFS and Stokes drift provided by ERA5. Model performance has been evaluated by comparisons with satellite-tracked surface drifters using normalized cumulative Lagrangian separation metrics and skill scores. Mean skill scores have reached 0.98 after 5 days and 0.95 after 10 days, remaining above 0.85 up to 20 days, indicating high reliability for short to intermediate forecasting horizons and suitability for probabilistic applications. Probabilistic simulations have revealed a pronounced seasonal effect, governed by the annual migration of the Intertropical Convergence Zone (ITCZ). During the JFMA period, shoreline impact probabilities have exceeded 40–50% along extensive portions of the French Guiana and Amapá state (Brazil) coastlines, with oil reaching the coast typically within 10–20 days. In contrast, during the JASO period, beaching probabilities have decreased to below 15%, accompanied by a substantial reduction in impact along the coastline and higher variability in arrival times. Although coastal exposure has been markedly reduced during JASO, a residual probability of approximately 2% of oil intrusion into the Amazonas river mouth has persisted. Full article

Background: Kidney transplantation activity at the University Hospital of Guadeloupe was briefly interrupted at the onset of the COVID-19 pandemic, reflecting the global impact of this health crisis on organ transplantation. This study assessed patient and graft recovery in 335 recipients transplanted between 2013 and 2023, comparing those transplanted before 2020 and after the resumption of activity. The objective was to evaluate changes in recipient profiles, surgical parameters, and post-transplant outcomes following this disruption. Methods: This retrospective cohort included all kidney transplants performed at the University Hospital of Guadeloupe over a ten-year period. Most patients (70%) received transplants before 2020, with 30% afterward. All grafts were ABO-compatible, and 98.2% were from deceased donors. Trends in transplant activity were analyzed to identify variations over time, with a peak observed in 2018, followed by a decline until 2021 and a progressive recovery from 2022. Comparative analyses were performed to examine disparities in donor and recipient characteristics, ischemia durations, and outcomes between the two periods. Results: After 2020, recipients were more likely to be elderly (≥70 years), immunized, obese, have heterozygous sickle cell disease, or have polycystic kidney disease (p < 0.05). Mean cold ischemia time decreased (p = 0.009), while warm ischemia time increased (p < 0.001), reflecting procedural and logistical adaptations. Graft survival remained stable, with 97.5% at 6 months and 89.8% at 4 years for transplants before 2020, versus 100% and 96.9%, respectively, after 2020 (p = 0.160). Patient survival did not differ significantly between periods (p = 0.199). Independent factors associated with mortality included recipient age ≥ 60 years, diabetes, graft failure, transplantation before 2020, cold ischemia time ≥ 1200 min, and graft pyelonephritis. Conclusions: Despite the temporary suspension of activity and an increased proportion of transplants with expanded criteria after 2020, graft recovery and patient survival were not adversely affected. These findings suggest that kidney transplantation in Guadeloupe demonstrated strong resilience and capacity for adaptation during and after the COVID-19 crisis, maintaining outcomes comparable to the pre-pandemic period. Full article

Various therapeutic approaches have been explored to speed up wound healing, with angiogenesis being a crucial factor in this process and skin repair. This study shows that a polysaccharide extracted from the red alga Osmundea pinnatifida (PSOP) can promote angiogenesis and accelerate healing. The structural properties of PSOP were investigated using various techniques, including scanning electron microscopy, X-ray diffraction, Fourier–transform infrared spectroscopy, ultraviolet–-visible spectroscopy, and high-performance liquid chromatography coupled with a refractive index detector. Additionally, the in vitro antioxidant activity of PSOP was evaluated using the reducing power assay, total antioxidant capacity measurement, and DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging tests. The PSOP extract exhibited significant pro-angiogenic effects in the avian chorioallantoic membrane model. Furthermore, the efficacy of PSOP-based hydrogels for wound healing was assessed in vivo using an excision wound model in Wistar rats. The results indicated accelerated wound healing, increased collagen deposition, and enhanced tissue regeneration. Computational studies suggest that the observed wound healing and pro-angiogenic effects may be attributed to the affinity of the PSOP units for cyclooxygenase-2 and vascular endothelial growth factor. These findings support the potential use of PSOP as a bioactive agent in wound care. Full article

Tuberculosis (TB) is still a significant public health threat, with rising drug resistance and high incidence in multiple areas worldwide. In the search for novel antitubercular agents, this study explores the application of a bioactivity-guided molecular networking approach to identify bioactive compounds from seven plant species (Curatella americana, Davilla nitida, Dipteryx punctata, Indigofera suffruticosa, Quassia amara, Tetradenia riparia, and Zingiber zerumbet) collected in French Guiana. Using ultrasound-assisted extraction followed by liquid–liquid partitioning and UHPLC-HRMS/MS analysis, a library of 72 samples was tested against Mycobacterium tuberculosis. The non-polar fractions from Indigofera suffruticosa, Tetradenia riparia, and Zingiber zerumbet showed the highest activity. The integration of metabolomic and bioassay data on molecular networks allowed the prioritization and annotation of active compounds, revealing flavonoids as contributors to the antitubercular activity of the active samples. In addition, the use of computational tools such as GNPS, SIRIUS, and TIMA-R enabled dereplication and increased the confidence in the structural prediction of active metabolites. This approach demonstrated its potential in accelerating the identification of both known and novel bioactive compounds without requiring exhaustive isolation, offering a robust strategy for natural product-based drug development against TB. Full article

This study aimed to determine the prevalence of type 1 diabetes mellitus (T1DM) in French Guiana and describe the social profiles of the patients. We conducted a multicenter cross-sectional study of children under 18 years who were diagnosed with type 1 diabetes and followed up from 2002 to 2021. Over a 20-year period, 48 children under 18 years with type 1 diabetes living in French Guiana were included in the study, out of a total of 59 cases. There were 26 girls and 22 boys. The median age at diagnosis was 8.52 years [IQR 6–12]. The incidence rate was 5.9 per 100,000 people in children aged 0–18 years. The 5–9-year age group was the most affected 43.7% (95% CI 38–51%). Of these children, 56.2% (95% confidence interval 40–70%) lived in single-parent households, and 35% (95% CI 23–57%) of the parents had a primary education. Of the children, 29% (95% CI 21–42%) were from families with no resources. Diabetes was diagnosed by ketoacidosis in 56% (95% CI 38–74%) of the patients. Forty percent (95% CI 35–66%) of the patients had an HbA1c > 9%. There was an imbalance in the prevalence of children with higher Hba1c (>9%), with 18.7% (95% CI 10–29%, p < 0.001) of children whose parents had a low level of education having an Hba1c > 9% compared with only 6% (95% CI 3–10%) of children whose parents had a university degree, and a marked imbalance in the prevalence of children with High Hba1c (>9%) among children from single-parent families (22.9%, 95% CI 17–30%) compared with children whose parents lived in couples (8%, 95% CI 5–12%). The 10–14-year age group (18.7%, 95% CI 11–25%) had the highest imbalance in the prevalence of poor diabetes control between children whose parents had lower versus higher education levels. Diabetic retinopathy and diabetic nephropathy were the only reported complications. The multivariate analysis showed that a low level of parental education (Odds ratio 2.9 [95% CI 2.1–4.5], p < 0.001) and single-parent families (Odds ratio 3.1 [95% CI 2.6–4.3], p < 0.001) were predictors of poor control of T1DM. However, the lack of social insurance coverage at diagnosis was not associated with poor T1DM control (p = 0.4). In conclusion, these sociodemographic factors should be considered when caring for children with T1DM in French Guiana. Full article

Anopheles darlingi is a major malaria vector in South America. Understanding its population dynamics is critical for designing effective vector control strategies. While various Anopheles collection methods exist, they may sample distinct populations. Microsatellite genotyping across nine loci was performed to characterize An. darlingi populations, which were collected in French Guiana between 6:30 p.m. and 7:00 a.m. using human landing catch (HLC) or Mosquito Magnet^® (MM) traps. Traps were arranged in a 3 × 3 Latin square design to minimize possible effects of geographical position. Pairwise F_ST index and discriminant analyses of principal components (DAPC) were used to make comparisons. A total of 431 An. darlingi were analyzed. No significant genetic differentiation was observed between collection methods or time slots (F_ST values non-significant, p > 0.25), with DAPC revealing a single genetic cluster. Despite documented phenotypic variations, no significant population structure was detected among An. darlingi sampled in a rural village in French Guiana via collection methods or time slots. These findings confirm that mosquitoes collected with these various methods or time slots are suitable for the molecular studies of An. darlingi in French Guiana. In this context, Mosquito Magnet^® traps could also represent an alternative to the now controversial human landing catch. Full article

Background/Objectives: This study evaluated the potential of a polysaccharide (PCS) extracted from the brown alga Cystoseira spinosa as an antioxidant and anti-inflammatory agent. Collected off the coast of Alkhoms, Libya, PCS was investigated for its wound-healing and pro-angiogenic properties, addressing the need for natural bioactive compounds in therapeutic applications. Methods: The monosaccharide composition of PCS was analyzed using HPLC-RID, identifying glucuronic acid and xylose as major components. In vitro tests assessed antioxidant activity, while in vivo experiments on 24 rats evaluated wound healing. Rats were divided into four groups: control (saline), standard drug (CYTOL CENTELLA cream), glycerol, and glycerol+PCS. Wound healing was analyzed macroscopically, histologically, and biochemically. The chick chorioallantoic membrane (CAM) model assessed pro-angiogenic effects, and computational analyses explored COX-2 and VEGF pathways. Pharmacokinetic properties were also evaluated. Results: PCS demonstrated significant antioxidant activity and accelerated wound healing after 16 days, with improved wound appearance scores and increased collagen content. Histological analysis confirmed PCS outperformed the standard drug. The CAM model showed PCS increased blood vessel density, length, and junctions while reducing lacunarity. Computational analyses supported involvement of COX-2 and VEGF pathways. Pharmacokinetic assessments indicated good bioavailability, non-inhibition of CYP enzymes, and favorable skin permeability. Conclusions: PCS shows promise as a natural bioactive polymer for wound healing and tissue regeneration. Its antioxidant, anti-inflammatory, and pro-angiogenic properties, combined with favorable pharmacokinetics, highlight its therapeutic potential. This study provides new insights into the mechanisms of C. spinosa polysaccharides and their application in promoting tissue repair. Full article

Background/Objectives: This study aimed to estimate the proportion of pediatric emergency admissions related to sickle cell disease. Methods: This is a cross-sectional study. The data were collected over a period of 9 years, from 1 January 2014 to 31 December 2022. Results: We recorded 858 emergency department visits related to sickle cell disease out of a total of 135,000 pediatric emergency department visits, giving a prevalence of 6.4 per 1000 children aged up to 18 years. The median age was 12 years (8–16) years. The average waiting time in the emergency department for children with sickle cell disease was 2 h (±1) in 2014 and 45 min (±15) in 2022. Children with sickle cell anemia were more likely than others to have been seen by a consultant in an emergency department. The most commonly associated pathology was asthma, with a frequency of 17%. The risk factors for hospitalization were an age between 5 and 10 years and a severe form of sickle cell disease. Conclusions: The treatment of pain and fever were often delayed. This leads us to suggest that systematic prior communication between the pediatric hematologist and the emergency physician is crucial. However, there is a need to define best practices for the management of children with sickle cell disease presenting to the emergency department with a fever. Full article

Snakebite represents a significant public health challenge in Central and South America, with Lachesis (Bushmaster) species posing unique clinical challenges due to their severe envenomation effects arising from a combination of potent venom and copious venom yields. Using in vitro coagulation assays, we analyzed the coagulotoxic venom effects from four distinct localities: L. muta from Surinam and French Guiana and L. stenophrys from Costa Rica and Panama. This study examined the venom’s impact on human plasma and fibrinogen and evaluated the efficacy of two regionally available antivenoms (PoliVal-ICP and Antivipmyn-Tri) in neutralizing the pathophysiological effects. Our results demonstrated a remarkable consistency in the pseudo-procoagulant venom activity (also known as: thrombin-like) across different species and localities. Antivenom efficacy testing revealed that both the PoliVal-ICP and Antivipmyn-Tri antivenoms effectively neutralized the venom effects across localities for both species, with the ICP antivenom showing the highest neutralization capacity. These toxicology findings highlight the biochemical conservation of venom composition across Lachesis species which underpins effective cross-neutralization in antivenom treatment. Full article

Internet of things (IoT) and big data technologies are increasingly gaining significance in the implementation of various services and applications. Consequently, much of the research focused on energy efficiency and building management revolves around integrating IoT and big data technologies for data collection and processing. Occupancy detection, comfort, and energy management are the most important services for optimizing building energy consumption in smart buildings, and environmental data play a key role in improving these services. Furthermore, the integration of advanced and recent techniques, such as IoT, big data, and machine learning, is progressively becoming more vital for both researchers and industries. This paper presents and discusses various emerging technologies that will contribute to designing novel IoT-based architectures to improve smart building services. These technologies offer innovative solutions to address the challenges of interoperability, scalability, and real-time data processing within intelligent environments, paving the way for more efficient, adaptive, and user-centric smart building systems. The main aim of this research is to help researchers define an optimal architecture that presents all layers, from sensing to big data stream processing. We established comparative criteria between the most popular data processing techniques to select the appropriate framework for developing intelligent platforms for managing building services, such as occupancy detection systems and occupants’ comfort management, and further, to enhance the deployment of digital twins for critical environment monitoring and anomaly detection. The proposed architecture uses Apache Kafka, Apache Storm, and Apache SAMOA as its core components, creating a comprehensive platform for efficient data collection, monitoring, and processing with high performance in terms of fault tolerance and low latency. Full article

The current range of the jaguar (Panthera onca) spans sixty degrees of latitude across eighteen countries in the Western Hemisphere and covers approximately 7,000,000 km². Throughout this geographical breadth, jaguars represent an essential component of native biological diversity, but conflict revolving around real and perceived jaguar depredation on livestock is a factor in jaguar mortality. We developed a structured questionnaire to evaluate the effectiveness of anti-depredation strategies from northern Mexico to Argentina, collecting data from 11 countries and 248 livestock operations, 194 with efficacy metrics, and 24 with benefit–cost ratios (value of the livestock losses averted/cost of the intervention). Using coarse categories, 11 intervention types were tested. Techniques effectively reducing livestock losses were documented across the entire livestock operation size (2–130,000 ha, 5–30,000 head) and biome spectrum. While the techniques varied in complexity and required levels of investment, successful reductions in depredation were achieved at all levels. We conclude that anti-depredation strategies are highly effective, and when benefits are evaluated, they surpass costs, sometimes substantially. Given the proven efficacy and cost-effectiveness of the techniques described in this paper, we advocate for broader application across the species range to increase tolerance towards jaguars and a more effective human–jaguar coexistence. Full article

This paper proposes new ANOVA-based approximations of functions and emulators of high-dimensional models using either available derivatives or local stochastic evaluations of such models. Our approach makes use of sensitivity indices to design adequate structures of emulators. For high-dimensional models with available derivatives, our derivative-based emulators reach dimension-free mean squared errors (MSEs) and a parametric rate of convergence (i.e., $\mathsf{O}\left(N^{-1}\right)$). This approach is extended to cope with every model (without available derivatives) by deriving global emulators that account for the local properties of models or simulators. Such generic emulators enjoy dimension-free biases, parametric rates of convergence, and MSEs that depend on the dimensionality. Dimension-free MSEs are obtained for high-dimensional models with particular distributions from the input. Our emulators are also competitive in dealing with different distributions of the input variables and selecting inputs and interactions. Simulations show the efficiency of our approach. Full article

Background: Dengue virus type 2 (DENV2) is endemic to hyperendemic in the French territories of the Americas (FTAs), including French Guiana, Guadeloupe, Martinique, Saint-Barthelemy, and Saint-Martin. In 2023–2024, French Guiana, Martinique, and Guadeloupe experienced unprecedented dengue epidemics partly associated with this serotype. In response, we conducted a retrospective study of the diversity of DENV2 strains circulating in the FTAs from 2000 to 2024. Methods: To this end, we selected DENV2 samples from the collection at the National Research Center for Arboviruses in French Guiana (NRCA-FG) and sequenced them using Oxford Nanopore Technologies (ONT)-based next-generation sequencing (NGS). Results: Phylogenetic analysis revealed that (i) the 77 DENV2 sequences from the FTAs belong to two distinct genotypes—Asian American and Cosmopolitan; (ii) from the 2000s up to the 2019 epidemic in French Guiana, all sequenced strains belonged to the Asian American genotype; (iii) and from 2019 to 2020, strains circulating in Martinique and Guadeloupe belonged to the Cosmopolitan genotype, specifically the Indian subcontinent sublineage, while (iv) strains from the 2023–2024 outbreak in Martinique, Guadeloupe, and French Guiana fall within a distinct sublineage of the same genotype—Other Cosmopolitan. Additionally, we analyzed amino acid (AA) changes in FTA sequences compared to the Dengvaxia^® and Qdenga^® vaccines. The analysis of amino acid changes in FTA sequences compared to the vaccines (Dengvaxia^® and Qdenga^®) identified 42 amino acid changes in the prM/E regions (15 in the prM region and 27 in the E region) relative to CYD-2 Dengvaxia^® and 46 amino acid changes in the prM/E regions relative to Qdenga^®, including 16 in the prM region and 30 in the E region. Some of these AA changes are shared across multiple genotypes and sublineages, with 8 substitutions in the prM region and 18 in the E region appearing in both analyses. This raises questions about the potential impact of these changes on vaccine efficacy. Conclusion: Overall, these findings provide a current overview of the genomic evolution of DENV2 in the FTA, which is crucial for developing more effective prevention and control strategies and for selecting future vaccines tailored to circulating strains. Full article

The present study investigates the potential capacity of fungi for the use in mercury (Hg) leaching and immobilization during the dissolution of cinnabar ore, the updated understanding of the mechanisms involved, and the evaluation of Hg absorption by these fungal strains. Two fungal strains are isolated from Hg-polluted soils in French Guiana and identified as Trichoderma koningiopsis and Talaromyces verruculosus. These fungal strains possess a high capacity for Hg resistance. The Hg concentrations causing 50% growth reduction (EC₅₀) are 5.9 and 1.5 ppm for T. koningiopsis and T. verruculosus, respectively. The results of medium-culture-containing cinnabar ore show that these fungal strains remove over 99% of the Hg content in the culture media by the end of the experiment. Fungal biomass decreases with increasing mercury concentration. The production of organic acids by fungi is observed for both fungal strains, leading to an acidic pH in the medium culture. Oxalic and citric acids are preferentially produced to dissolve Fe from minerals, which may impact Hg leaching. The results of this study provide evidence that the two fungi seem to have potential use for the bioremediation of Hg during the dissolution of cinnabar ores through biosorption mechanisms. Full article