Intra-seasonal variability of smoke aerosol optical depth (AOD) and downwelling solar irradiance at the surface during the 2002 biomass burning season in South America was modeled using the Coupled Chemistry-Aerosol-Tracers Transport model with the Brazilian developments on the Regional Atmospheric Modeling System (CCATT-BRAMS). Measurements of total and fine mode fraction (FMF) AOD from the AErosol RObotic NETwork (AERONET) and solar irradiance at the surface from the Solar Radiation Network (SolRad-NET) were used to evaluate model results. In general, the major features associated with AOD evolution over the southern part of the Amazon basin and cerrado ecosystem are captured by the model. The main discrepancies were found for high aerosol loading events. In the northeastern portion of the Amazon basin the model systematically underestimated total AOD, as expected, since smoke contribution is not dominant as it is in the southern portion and emissions other than smoke were not considered in the simulation. Better agreement was obtained comparing the model results with observed FMF AOD, which pointed out the relevance of coarse mode aerosol emission in that region. Likewise, major discrepancies over cerrado during high AOD events were found to be associated with coarse mode aerosol omission in our model. The issue of high aerosol loading events in the southern part of the Amazon was related to difficulties in predicting the smoke AOD field, which was discussed in the context of emissions shortcomings. The Cuiabá cerrado site was the only one where the highest quality AERONET data were unavailable for both total and FMF AOD. Thus, lower quality data were used. Root-mean-square error (RMSE) between the model and observed FMF AOD decreased from 0.34 to 0.19 when extreme AOD events (FMF AOD550 nm ≥ 1.0) and Cuiabá were excluded from the analysis. Downward surface solar irradiance comparisons also followed similar trends when extreme AOD were excluded. This highlights the need to improve modelling of the regional smoke plume in order to enhance the accuracy of the radiative energy budget. An aerosol optical model based on the mean intensive properties of smoke from the southern part of the Amazon basin produced a radiative flux perturbation efficiency (RFPE) of −158 Wm−2/AOD550 nm at noon. This value falls between −154 Wm−2/AOD550 nm and −187 Wm−2/AOD550 nm, the range obtained when spatially varying optical models were considered. The 24 h average surface radiative flux perturbation over the biomass burning season varied from −55 Wm−2 close to smoke sources in the southern part of the Amazon basin and cerrado to −10 Wm−2 in remote regions of the southeast Brazilian coast
Fungal spores are ubiquitous biological aerosols, which are considered to actas ice nuclei. In this study the ice nucleation (IN) activity of sporesharvested from 29 fungal strains belonging to 21 different species was testedin the immersion freezing mode by microscopic observation of water-in-oilemulsions. Spores of 8 of these strains were also investigated in amicrodroplet freezing array instrument. The focus was laid on species ofeconomical, ecological or sanitary significance. Besides common molds(Ascomycota), some representatives of the widespread group of mushrooms(Basidiomycota) were also investigated. Fusarium avenaceum was the only sample showing IN activity atrelatively high temperatures (about 264 K), while the other investigatedfungal spores showed no freezing above 248 K. Many of the samples indeedfroze at homogeneous ice nucleation temperatures (about 237 K). Incombination with other studies, this suggests that only a limited number ofspecies may act as atmospheric ice nuclei. This would be analogous to what isalready known for the bacterial ice nuclei. Apart from that, we selected a set of fungal strains from different sites andexposed them to occasional freezing stress during their cultivation. This wasin order to test if the exposure to a cold environment encourages theexpression of ice nuclei during growth as a way of adaptation. Although thetotal protein expression was altered by this treatment, it had no significantimpact on the IN activity
Studies indicate that tooth crown diameters are clinical markers for sex differentiation. Therefore, the aim of this study was to assess the degree of sexual dimorphism in different teeth. Maximum mesiodistal (MD) and buccolingual (BL) dimensions of 2400 permanent teeth from 100 pretreatment orthodontic dental study casts and clinical records (50 males and 50 females) from the Department of Pediatric Dentistry and Orthodontics, Federal University of Rio de Janeiro, Brazil, were examined. Comparison of the MD and BL dimensions between males and females was performed using the Student’s t test with alpha 0.05, effect size, and discriminant function analysis. Comparisons in MD and BL widths between sexes demonstrated that the combined mean in the female group presented reduction when compared with the male group, except for the BL dimension of tooth 26. In regard to the MD dimensions, statistically significant differences were observed in various dental groups. The greatest sexual dimorphism was observed in the left mandibular canine (p<0.001) with effect size over 0.8 (0.94), which characterizes large effect. In BL dimension, numerous teeth demonstrated statistical differences between the sexes. Our findings reinforced the magnitude of sexual dimorphism in tooth size, and, in addition, highlighted the differences in specific dental groups