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Suitability of band angle indices for burned area mapping in the Maule Region (Chile)
No full textIn January 2017, 114 active fires burned throughout Chile at the same time. These fires spread quickly due to high temperatures, fast dry winds, and low vegetation water content. The fire events burned more than 570,000 ha, from which 20% of the area was endangered native forest. Timely and accurate burned area mapping is crucial for the evaluation of damages and management of the affected areas. As Chile is a diverse country with many types of ecosystems and vegetation, the use of novel spectral indices may improve the accuracy of satellite data-based burned area mapping algorithms. In this study, we explored the contribution of band angle indices (BAnI) to burned area mapping. The BAnI are based on trigonometric equations that proved to be sensitive to moisture conditions. Then, we aimed to test their sensitivity to the burned area spectral signature. We used Sentinel-2 data at 20 m resolution to calibrate and implement a random forest (RF) classifier in Google Earth Engine (GEE) computing platform. We ran the RF classifier with and without BAnI to evaluate their potential to identify burned areas and performed two accuracy assessments comparing the results with visually digitized fire perimeters from (1) WorldView 3 (WV3) images, and (2) Sentinel at 10 m resolution. We determined that both BA classifications were more accurate than the perimeters created by the Chilean National Forest Corporation (CONAF), which overestimates the area burnt. The overestimation of CONAF perimeters is produced by considering as burned the inner unburned areas and omitting some small, burned areas. The first assessment showed no significant differences between the two RF classifications. However, the second validation showed lower omission and commission errors for the RF classifier with the BAnI (5 and 17.8%, respectively). On the other hand, comparing both BA classifications with and without BAnI, we observed differences in the spatial distribution of the errors. However, the RF classification with BAnI offered fewer commission errors located in agricultural areas. The burned area algorithms developed in GEE showed their potential to map the fire-affected area quickly, efficiently, and accurately, accounting for all the areas burned in the season, including the small and agricultural fires the official perimeters did not consider
Editorial: Impacts of climate change on long term viability of tree species with recalcitrant seeds
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Research-Based Learning to strengthen initial teacher training in Pedagogy in Physical Education
No full textLa sistematización de la presente experiencia pedagógica explica la implementación de un programa piloto de Aprendizaje Basado en Investigación (ABI) en el proceso de Formación Inicial Docente (FID) del Profesorado de Educación FÃsica (PEF) perteneciente a una universidad chilena. La experiencia se desarrolló con clases en modalidad virtual durante el segundo semestre del 2021. El programa abordó siete temáticas en ocho sesiones de clases. El objetivo del programa piloto fue desarrollar competencias investigativas en el profesorado en proceso de FID en PEF orientadas a su área de formación de manera remota. Los resultados demostraron que el 100% de los asistentes al programa piloto mejoraron el nivel de conocimiento en cuanto a las temáticas del ABI, por otra parte, el 100% de los asistentes declaró estar satisfecho con este tipo de experiencias. Se puede concluir que la implementación del ABI en la FID en PEF se sustenta en la necesidad de potenciar el ámbito investigativo desde sus bases (estudiantes), siendo una estrategia de enseñanza-aprendizaje que facilitará la búsqueda de soluciones a los problemas utilizando una metodologÃa innovadora que permite construir nuevo conocimiento desde sus propias realidades
Environmental signature and health risk assessment of polybrominated diphenyl ethers (PBDEs) emitted from a landfill fire in Santiago de Chile
No full textPolybrominated diphenyl ethers (PBDEs) have been used as flame retardants in building materials, electronics, furnishings, vehicles, airplanes, plastics, polyurethane foams, and textiles for many years. Currently, the primary commercial mixtures, penta-, octa-, and deca-BDE, are globally restricted. Still, products containing PBDEs are expected to impact waste management and the environment for many years. In January 2016, an open fire in the Santa Marta landfill close to Santiago de Chile affected the city and surroundings. The fire caused several acute health effects and an increase in emergency hospitalizations. We measured PBDE levels in the areas affected by the fire in the air (gaseous and particulate) and soil, and PBDE emissions were estimated using a dispersion model. The results showed an increase in PBDE concentrations by a factor of 2-4 one day after the start of the fire. However, PBDE concentrations measured after the fire in PM10 and the gas phase were considered low compared to other regions. Interestingly, PBDEs' patterns differed across the sites; however, BDE209 was the dominant congener for all environmental matrices. A preliminary risk assessment was conducted using the daily exposure dose (DED) by air inhalation estimation. The results showed low DED values for adults and children and suggested no direct health risk due to PBDE exposure. This study brings new data useful for future solid waste management initiatives in the country.This study was funded by Agencia Nacional de Investigacion y Desarrollo (ANID) through projects Fondecyt 1161673 (KP), 1211931 (KP), 1210946 (CG-M), ANID-PIA-INACh-ACT192057 (CG-M and VG), and ANID/FONDAP project 1522A0002 (HJ). The authors thank the RECETOX RI (No LM2023069) financed by the Ministry of Education, Youth and Sports of the Czech Republic, and Operational Programme Research, Development, and Education - project CETOCOEN EXCELLENCE (No CZ.02.1.01/0.0/0.0/17_043/0009632) for supportive background. It was furthermore supported by the European Union's Horizon 2020 programme under grant agreement No 857560. This publication only reflects the author's view, and the European Commission is not responsible for any use that may be made of the information it contains
Phylogenomic analysis of the Porphyromonas gingivalis-Porphyromonas gulae duo: approaches to the origin of periodontitis
No full textPorphyromonas gingivalis is an oral human pathogen associated with the onset and progression of periodontitis, a chronic immune-inflammatory disease characterized by the destruction of the teeth-supporting tissue. P. gingivalis belongs to the genus Porphyromonas, which is characterized by being composed of Gram-negative, asaccharolytic, non-spore-forming, non-motile, obligatory anaerobic species, inhabiting niches such as the oral cavity, urogenital tract, gastrointestinal tract and infected wound from different mammals including humans. Among the Porphyromonas genus, P. gingivalis stands out for its specificity in colonizing the human oral cavity and its keystone pathogen role in periodontitis pathogenesis. To understand the evolutionary process behind P. gingivalis in the context of the Pophyoromonas genus, in this study, we performed a comparative genomics study with publicly available Porphyromonas genomes, focused on four main objectives: (A) to confirm the phylogenetic position of P. gingivalis in the Porphyromonas genus by phylogenomic analysis; (B) the definition and comparison of the pangenomes of P. gingivalis and its relative P. gulae; and (C) the evaluation of the gene family gain/loss events during the divergence of P. gingivalis and P. gulae; (D) the evaluation of the evolutionary pressure (represented by the calculation of Tajima-D values and dN/dS ratios) comparing gene families of P. gingivalis and P. gulae. Our analysis found 84 high-quality assemblies representing P. gingivalis and 14 P. gulae strains (from a total of 233 Porphyromonas genomes). Phylogenomic analysis confirmed that P. gingivalis and P. gulae are highly related lineages, close to P. loveana. Both organisms harbored open pangenomes, with a strong core-to-accessory ratio for housekeeping genes and a negative ratio for unknown function genes. Our analyses also characterized the gene set differentiating P. gulae from P. gingivalis, mainly associated with unknown functions. Relevant virulence factors, such as the FimA, Mfa1, and the hemagglutinins, are conserved in P. gulae, P. gingivalis, and P. loveana, suggesting that the origin of those factors occurred previous to the P. gulae - P. gingivalis divergence. These results suggest an unexpected evolutionary relationship between the P. gulae - P. gingivalis duo and P. loveana, showing more clues about the origin of the role of those organisms in periodontitis.JC is supported by ANID Fondecyt project 11200209, CC is supported by ANID Fondecyt project 11190073, and JR-P is supported by ANID Fondecyt project 1221064. JN-B is supported by the Integrative Genomics Ph.D. program (Universidad Mayor, Chile)
Age-Dependent Behavioral and Synaptic Dysfunction Impairment Are Improved with Long-Term Andrographolide Administration in Long-Lived Female Degus (Octodon degus)
No full textIn Octodon degus, the aging process is not equivalent between sexes and worsens for females. To determine the beginning of detrimental features in females and the ways in which to improve them, we compared adult females (36 months old) and aged females (72 months old) treated with Andrographolide (ANDRO), the primary ingredient in Andrographis paniculata. Our behavioral data demonstrated that age does not affect recognition memory and preference for novel experiences, but ANDRO increases these at both ages. Sociability was also not affected by age; however, social recognition and long-term memory were lower in the aged females than adults but were restored with ANDRO. The synaptic physiology data from brain slices showed that adults have more basal synaptic efficiency than aged degus; however, ANDRO reduced basal activity in adults, while it increased long-term potentiation (LTP). Instead, ANDRO increased the basal synaptic activity and LTP in aged females. Age-dependent changes were also observed in synaptic proteins, where aged females have higher synaptotagmin (SYT) and lower postsynaptic density protein-95 (PSD95) levels than adults. ANDRO increased the N-methyl D-aspartate receptor subtype 2B (NR2B) at both ages and the PSD95 and Homer1 only in the aged. Thus, females exposed to long-term ANDRO administration show improved complex behaviors related to age-detrimental effects, modulating mechanisms of synaptic transmission, and proteins.This research was funded by FONDECYT, grant number 11190603 to D.S.R.; the CONICYT-PFB 12/2007 and AFB grant number 170005 to N.C.I.; FONDECYT, grant number 1221178 and Centro Ciencia & Vida, FB210008, Financiamiento Basal para Centros Cientificos y Tecnologicos de Excelencia de ANID to C.T.R; and the CAPES-CONICYT 0002-2014 (Line 3) to F.B
Border Closure Only Increased Precariousness: A Qualitative Analysis Of The Effects Of Restrictive Measures During The Covid 19 Pandemic On Venezuelan's Health And Human Rights In South America
No full textNext Steps To Advance General Physical Activity Recommendations Towards Physical Exercise Prescription: A Narrative Review
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