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Copyright of ESPOCH Congresses: The Ecuadorian Journal of S.T.E.A.M. is the property of Knowledge E DMCC and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We use the maps elaborated within the Mexican Mangrove Monitoring System (MMMS) project of the National Commission for Knowledge and Use of Biodiversity (CONABIO) to analyze the changes in mangrove area distribution during the last 45 years, within the framework of the coastal regional characteristics in Mexico. We found that 19% of the primary mangrove area identified in 1970/1980 was lost and that 9.4% was gained as secondary mangrove forests due to the colonization of new or disturbed areas. Using location and residence stability indexes, we identified two main change dynamics within three periods (1970/1980–2005, 2005–2010 and 2010–2015): (1) the dominant effect of climate change, especially in northwest Mexico and (2) the dominant effect of anthropic activities, mainly in the Gulf of Mexico. Significant differences in changes in the area of mangroves between regions over time highlight the relevance of more detailed and local studies to understand the processes leading to the degradation or conservation of mangroves. [ABSTRACT FROM AUTHOR]

An imbalance in the redox state, increased levels of lipid precursors and overactivation of de novo lipogenesis determine the development of fibrosis during nonalcoholic steatohepatitis (NASH). We evaluated the modulation of NADPH-producing enzymes associated with the antifibrotic, antioxidant and antilipemic effects of nicotinamide (NAM) in a model of NASH induced by excess fructose consumption. Male rats were provided drinking water containing 40% fructose for 16 weeks. During the last 12 weeks of fructose administration, water containing NAM was provided to some of the rats for 5 h/day. The biochemical profiles and the ghrelin, leptin, lipoperoxidation and TNF-α levels in serum and the glucose-6-phosphate dehydrogenase (G6PD), malic enzyme (ME) and NADP+-dependent isocitric dehydrogenase (IDP) levels, the reduced/oxidized glutathione (GSH/GSSG) and reduced/oxidized nicotinamide adenine dinucleotide (phosphate) (NAD(P)H/NAD(P)+) ratios, and the levels of various lipogenic and fibrotic markers in the liver were evaluated. The results showed that hepatic fibrosis induced by fructose consumption was associated with weight gain, hunger-satiety system dysregulation, hyperinsulinemia, dyslipidemia, lipoperoxidation and inflammation. Moreover, increased levels of hepatic G6PD and ME activity and expression, the NAD(P)H/NAD(P)+ ratios, and GSSG concentration and increased expression of lipogenic and fibrotic markers were detected, and these alterations were attenuated by NAM administration. Specifically, NAM diminished the activity and expression of G6PD and ME, and this effect was associated with a decrease in the NADPH/NADP+ ratios, increased GSH levels and decreased lipoperoxidation and inflammation, ameliorating fibrosis and NASH development. NAM reduces liver steatosis and fibrosis by regulating redox homeostasis through a G6PD- and ME-dependent mechanism. [ABSTRACT FROM AUTHOR]

For each finite set S of prime numbers there exists a unique completion ℚ of ℚ, which is a second countable, locally compact and totally disconnected topological ring. This topological ring has a natural ultrametric that allows to define a pseudodifferential operator D and to study an abstract heat equation on the Hilbert space L (ℚ). The fundamental solution of this equation is a normal transition function of a Markov process on ℚ. The techniques developed provides a general framework for these kind of problems on different ultrametric groups. [ABSTRACT FROM AUTHOR]

This article introduces several rotation and additive invariant ultrametrics on the finite adèle ring A of the rational numbers ℚ. Symmetry, regularity and uniqueness properties of these ultrametrics are provided. With these non-Archimedean metrics at hand it is possible to define a wide class of rotation and additive invariant Markov processes on A. [ABSTRACT FROM AUTHOR]

Understanding the linkage between accumulated fuel dryness and temporal fire occurrence risk is key for improving decision-making in forest fire management, especially under growing conditions of vegetation stress associated with climate change. This study addresses the development of models to predict the number of 10-day observed Moderate-Resolution Imaging Spectroradiometer (MODIS) active fire hotspots—expressed as a Fire Hotspot Density index (FHD)—from an Accumulated Fuel Dryness Index (AcFDI), for 17 main vegetation types and regions in Mexico, for the period 2011–2015. The AcFDI was calculated by applying vegetation-specific thresholds for fire occurrence to a satellite-based fuel dryness index (FDI), which was developed after the structure of the Fire Potential Index (FPI). Linear and non-linear models were tested for the prediction of FHD from FDI and AcFDI. Non-linear quantile regression models gave the best results for predicting FHD using AcFDI, together with auto-regression from previously observed hotspot density values. The predictions of 10-day observed FHD values were reasonably good with R2 values of 0.5 to 0.7 suggesting the potential to be used as an operational tool for predicting the expected number of fire hotspots by vegetation type and region in Mexico. The presented modeling strategy could be replicated for any fire danger index in any region, based on information from MODIS or other remote sensors. [ABSTRACT FROM AUTHOR]