Soil-landform-vegetation interplays at Stinker Point, Elephant Island, Antarctica.

The geomorphic dynamics on ice-free areas are crucial for understanding soil formation, vegetation and landscape stability in maritime Antarctic. We aimed to describe the soil formation on different landforms, following the Holocene glacial retreat at Stinker Point. Twenty profiles were sampled and classified, grouped into three landforms units: middle platforms and scarps, till/glacial deposits and present/Holocene raised beaches. Soil chemical and physical attributes were determined, and the vegetation type identified and quantified. Soils from till and glacial deposits can be separated by the age of exposure: older soils are stony, skeletic; and recently exposed till has soils with moderate depth, alkaline reaction and very high base saturation. Soils at the middle platforms are shallow, coarse-grained, skeletic, with abundant vegetation. Soils from the present-day beaches are alkaline, very coarse with no horizon differentiation, whereas soils on Holocene beaches are acid and nutrient-rich due to past or present-day influence of fauna. Soils from Stinker Point are generally shallow, skeletic and strongly related to the landforms and biogenic influences. Compared with other islands of the South Shetlands, in Elephant Island soil development is less pronounced, being this mainly attributed to the metamorphic nature of parent material, with greater resistance to weathering.

The diversity and structure of plant communities in the maritime Antarctic is shaped by southern giant petrel's (Macronectes giganteus) breeding activities.

Southern giant petrels (Macronectes giganteus) are found in the Antarctic. They build their nests with rock fragments, disturbing large areas during incubation and chick feeding periods; however, their impact on vegetation is unknown. Thus, we aimed to evaluate the effect of Petrel nests and associated breeding activities on the diversity and structure of cryptogam communities of Stinker Point, Elephant Island. We selected 13 nests in February and March 2012 and continue the monitoring in 2018. The area of direct influence of breeding activities was photographed to calculate plant community coverage. The results demonstrated that species richness, community coverage and composition, and beta diversity showed significant differences between active and inactive nests. The linear mixed-effect models revealed that the positive effect of nest area mainly caused variation in community coverage, but had a negative effect on beta diversity. Sphaerophorus globosus (lichen) grew around the inactive nests, sometimes forming a ring up to 1 m in diameter. This ring was then surrounded by the Chorisodontium acyphyllum moss colonized by S. globosus, and a final ring of Sanionia uncinata, colonized by the same lichen. Recently constructed nests are generally surrounded by Prasiola crispa and Sanionia uncinata carpets.

Forest restoration methods, seasonality, and penetration resistance does not influence aboveground biomass stock on mining tailings in Mariana, Brazil.

The restoration methods applied on the areas affected by the Fundão tailings dam collapse have a high priority in Mariana region. We evaluated the effect of different restoration methods and site preparation techniques, depth and seasonality on penetration resistance of tailings, and how these predictors affect tree aboveground biomass in areas affected by the Fundão dam collapse in Mariana, Brazil. No significant differences in penetration resistance and aboveground biomass between treatments were observed, but significant differences were observed between seasonal periods. The main univariate model explained the significant effects of depth and seasonality, mainly by a negatively wet effect on penetration resistance. According to the best models (univariate and multivariate) were those that had depth as a predictor. This study showed how penetration resistance can be an indicator to select the best period for restoration process in areas affected by the collapse of the Fundão dam, but no limit to the aboveground biomass recovery on tailing.

Influence of grilling pretreatment and optimization of sous vide processing parameters on the physicochemical and microbiological quality of pirarucu fillet.

The demand for high-quality food products has promoted the study of techniques for its processing and conservation. The present research aimed to evaluate the influence of grilling pretreatment on the physical characteristics of pirarucu fillets and the heat transfer process by a computational modelling, and to optimize the sous vide process parameters. Before and after the sous vide process, the samples were analysed for microbiological, chemical and physical characteristics. There was no significant difference between the total experimental time of grilling and that obtained by computational modelling. Immersion in brine for 300 s in combination with grilling at 200 ℃/120 s was selected because of its water-holding capacity (%) 79.40 ± 0.31, texture (N) 1.91 ± 0.40 and value of L* 74.44 ± 0.38 in the fillets. Cooking at 60 ℃ for 568.8 s were the best sous vide parameters obtained, with highest water-holding capacity (%) 93.60, texture (N) 6.24, ΔE* 7.43, and with microbiological loads below 6 log CFU/g and 7 log MPN/g in the final product. Useful information obtained from this study highlighted the brine and grill pretreatment in combination with sous vide proved it is a potential solution for developing pirarucu products even at an industrial scale.

Local-scale Seasonality Shapes Anuran Community Abundance in a Cloud Forest of the Tropical Andes.

Analysing how seasonality shapes abundance patterns fosters understanding of the processes related to amphibian community assemblies. In this study we analyse the relationship between local seasonal patterns of abundance within the anuran community of the Monte Zerpa Cloud Forest, Mérida Mountain Range (Cordillera de Mérida), in the Venezuelan Andes. We hypothesized that variation in precipitation, temperature, and relative humidity affects the temporal abundance patterns of anurans. Data collection was performed through nocturnal biweekly inspections from 2002 to 2003. Air temperature, relative humidity, and monthly precipitation were considered as variables of climatic seasonality. Generalized linear models were used to evaluate the effect of climatic variables on anuran abundance across seasons. Overall, 542 individuals and four anuran species were recorded in stream tributaries only. The local anuran community was comprised of Hyalinobatrachium duranti, Hyloscirtus platydactylus, Hyloscirtus jahni, and Pristimantis vanadisae. The most abundant species were H. duranti (288 individuals) and H. platydactylus (145 individuals), representing 53% and 27% of the total anuran abundance, respectively. Differences in abundance between species were observed. Although the total abundance of anurans was higher during the low precipitation season, no significant differences between the two seasons were detected. The variation in anuran abundance was explained by relative humidity and temperature. Our results suggest that the highest abundance of anurans can be expected when temperatures reach favourable levels (15- 17°C), relative humidity increases, and precipitation remains constant.

Endothelial cell loss after pars plana vitrectomy in patients with previous endothelial keratoplasty.

PURPOSE: To describe the changes in endothelial cell density after pars plana vitrectomy (PPV) in patients with previous Descemet stripping with automated endothelial keratoplasty (DSAEK). METHODS: Pars plana vitrectomy was performed in 3 eyes after DSAEK (16, 14, and 7 months, respectively). Two patients had a retinal detachment and the third patient had an epiretinal membrane. The cell population density and corrected distance visual acuity (CDVA) were measured before and after PPV. RESULTS: Two months after PPV, the average endothelial cell loss was 11.12% (range 10.3%-12.15%). One patient lost 2 lines of CDVA and the other 2 patients lost only half a line of Snellen CDVA. CONCLUSIONS: Patients who have undergone DSAEK may experience accelerated endothelial cell loss after a subsequent PPV procedure but the extra cell loss should not pose a short-term risk to graft viability unless the endothelial cell density was already borderline.