ABSTRACT
During the summer of 2017, several megafires in South-Central Chile burned down forest plantations, native forests, shrublands and human settlements. National authorities identified the relevant effects of the wildfires on infrastructure and ecosystems. However, other indirect effects such as the risk of flooding or, increased air pollution were not assessed. The present study assesses: i) the geographic characterization of wildfires, ii) amount of damage to ecosystems and the severity of wildfires, iii) the effects of megafires on air quality in nearby and distant urban areas, and iv) identification of cities potentially exposed to landslides and flooding. We ran remote sensing analyses based on the Normalized Burn Ratio taken from Landsat imagery, "active fires" from MODIS, and ASTER GDEM. The particulate matter (PM10 and PM2.5) levels measured on 34 Chilean's municipalities were correlated with the burning area/distance ratio by Spearman correlation. Socionatural hazards were evaluated using multi-criteria analyses combining proximity to burned areas, severity, potential flow of water and sediments as indicated by the Digital Elevation Model, drainage networks and the location of human settlements. 91 burned areas were identified, covering 529,794â¯ha. The most affected ecosystems were forest plantations and native shrublands. We found significant correlations between burned area/distance ratios and PM2.5 and PM10 levels, leading to increased levels over the Chilean air quality standard in the most populated cities. 37 human settlements were at increased risk of landslides and flooding hazards after fires and eleven could now be characterized as dangerously exposed. The 2017 wildfires in Chile have had an impact at both a small and large scale, with far-reaching air pollutants dispersing and affecting >74% of the Chilean population. The impact of the wildfires was also extended over time, creating future potential for landslides and flooding, with the risk increasing in rainy seasons.
ABSTRACT
Las translocaciones robertsonianas son las anomalías cromosómicas más frecuentes en seres humanos. En pacientes portadores sanos de esta translocación se pueden generar gametos no balanceados y progenie con la trisomía y disomía uniparental y, por lo tanto, problemas reproductivos. En el presente artículo se estudió a una pareja con antecedentes de abortos recurrentes. Se realizó un estudio citogenético obtenido a partir de un cultivo estandarizado de linfocitos, resultando en ambos pacientes un cariotipo normal. Posteriormente, se analizó el producto de un aborto espontáneo de nueve semanas de edad gestacional, encontrándose un resultado 46,XY, t(21;21)(q10;q10), +21 correspondiente a una trisomía 21 por translocación. Una posible explicación al aborto por translocación robertsoniana, se obtuvo después de revisar las placas metafásicas del hombre y la mujer, observándose asociaciones entre los cromosomas acrocéntricos de la mujer. Al relacionarse el antecedente de abortos recurrentes, el resultado de la trisomía 21 por translocación y las asociaciones entre cromosomas acrocéntricos en la mujer nos llevó a considerar a esta asociación como un factor causal de los abortos en la pareja.
Robertsonian translocations are the most frequent chromosomal anomalies in humans. Healthy carriers of these translocations can generate unbalanced gametes and off spring with trisomy and uniparental disomy and therefore, reproductive problems. In the present article, a couple with antecedents of recurrent abortions was studied. Cytogenetic analysis performed after standard lymphocyte cultures, resulted in a normal karyotype for the couple. Analysis of the nine weeks of gestational age spontaneous abortion, resulted in a 46,XY, t(21;21)(q10;q10), +21 corresponding to a trisomy 21 due to translocation. A possible explanation for the abortion due to robertsonian translocation was obtained after checking metaphases of the man and the woman's cultures, associations being observed between the acrocentric chromosomes of the woman. Attempting to relate recurrent abortions to the result of trisomy 21 due to translocation and the associations between acrocentric chromosomes in the woman, led us to consider this association, as a causal factor for abortions in the couple.
