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Mercury in soils impacted by alluvial gold mining in the Peruvian Amazon
No full textGold mining is the largest source of mercury (Hg) pollution worldwide. The discharge of mercury in the environment bears direct human health risks and is likely to increase cascading effects throughout local food chains. In the Peruvian Amazon the mining process consists of slashing and burning trees, followed by extraction of gold-bearing sediment, amalgamation with Hg and gold recovery, leading each year to the degradation of 6,000-10,000 ha and the release of 180 metric tons of Hg per year to the enviroment. The purpose of this study was to determine soil Hg levels in soils of abandoned alluvial gold mine spoils and undisturbed forest in the Madre de Dios region, the epicenter of alluvial gold mining in Peru. We selected gold mine spoils of the two most important technologies locally applied for gold extraction, i.e., Minimally Mechanized Mining (MMM) and Highly Mechanized Mining (HMM), in the native communities of Laberinto and Kotzimba, respectively. We collected 127 and 35 soil samples (0-20cm depth) from potentially contaminated sites and undisturbed forest, respectively. Physicochemical analysis and determination of Hg levels were determined for all soil samples. None of the samples had Hg concentrations above Peruvian, Canadian and British Environmental Quality Standards for Agricultural Soil (6.6mg/kg). Hg levels in MMM and HMM were not significantly different between the two areas. The main variables explaining variation of soil Hg concentrations were the vegetation cover, soil organic matter, soil pH and clay particle content, which explained up to 80% of data set variation. Surprisingly, highest Hg concentrations were found in untouched old-growth forest bordering the mine spoils, but there was also a trend of increasing Hg concentrations with the regenerating vegetation. Our findings suggest that Hg concentrations in old mine spoils are low and shouldn't stand in the way of efforts to restore soil conditions and develop sustainable land uses. However, it is urgent to end the use of Hg in mining operation to decrease human and environmental risks. © 2021 Elsevier LtdConsejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Late Neogene evolution of the Peruvian margin and its ecosystems: a synthesis from the Sacaco record
No full textThe highly productive waters of the Humboldt Current System (HCS) host a particular temperate ecosystem within the tropics, whose history is still largely unknown. The Pisco Formation, deposited during Mio-Pliocene times in the Peruvian continental margin has yielded an outstanding collection of coastal-marine fossils, providing an opportunity to understand the genesis of the HCS ecosystem. We present a comprehensive review, completed with new results, that integrates geological and paleontological data from the last 10 My, especially focusing on the southern East Pisco Basin (Sacaco area). We discuss the depositional settings of the Pisco Formation and integrate new U/Pb radiometric ages into the chronostratigraphic framework of the Sacaco sub-basin. The last preserved Pisco sediments at Sacaco were deposited ~ 4.5 Ma, while the overlying Caracoles Formation accumulated from ~ 2.7 Ma onwards. We identified a Pliocene angular unconformity encompassing 1.7 My between these formations, associated with a regional phase of uplift. Local and regional paleoenvironmental indicators suggest that shallow settings influenced by the offshore upwelling of ventilated and warm waters prevailed until the early Pliocene. We present an extensive synthesis of the late Miocene–Pleistocene vertebrate fossil record, which allows for an ecological characterization of the coastal-marine communities, an assessment of biodiversity trends, and changes in coastal-marine lineages in relation to modern HCS faunas. Our synthesis shows that: (i) typical endemic coastal Pisco vertebrates persisted up to ~ 4.5 Ma, (ii) first modern HCS toothed cetaceans appear at ~ 7–6 Ma, coinciding with a decline in genus diversity, and (iii) a vertebrate community closer to the current HCS was only reached after 2.7 Ma. The genesis of the Peruvian coastal ecosystem seems to be driven by a combination of stepwise transformations of the coastal geomorphology related to local tectonic pulses and by a global cooling trend leading to the modern oceanic circulation system. © 2021, Geologische Vereinigung e.V. (GV)
Effect of augmented reality books in salivary cortisol levels in hospitalized pediatric patients: A randomized cross-over trial
No full textObjective: This study sought to assess the effect of reading augmented reality (AR) books on salivary cortisol levels in hospitalized pediatric patients compared to reading a standard children's book. Methods: This was a randomized, two-period, cross-over trial in hospitalized children aged 7–11 years. AR books currently in the market were used as intervention. Complete block randomization was used to randomize the order of the intervention. Children allocated to the ‘AR-first’ group received the book, a tablet and were left to interact independently with the technology for an hour. After a 48 -h wash-out period, children received a standard book. ‘Standard-book-first’ group received only the standard book and after wash-out received the tablet and the AR book. Salivary cortisol and a validated visual analogue scale (VAS) for psychological stress were assessed at the beginning and at the end of each intervention. Results: A total of 29 children were recruited in the study. One was lost during follow up. Cortisol levels decreased after the AR intervention (P = 0.019). Nevertheless, the decrease was not greater than the one associated to reading the standard book. VAS scores increased after the AR intervention (P < 0.001). Discussion: There is evidence of order and sequence effects that might explain results. First assessment of AR-based interventions on stress. Results justify further research. Conclusions: There was no evidence that reading AR books diminished cortisol levels more than reading a standard book. AR-books improved VAS score for psychological stress compared to a standard book. © 2021 Elsevier B.V.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
Changes in inflammatory gene expression in brain tissue adjacent and distant to a viable cyst in a rat model for neurocysticercosis
No full textBackground The parasite Taenia solium causes neurocysticercosis (NCC) in humans and is a common cause of adult-onset epilepsy in the developing world. Hippocampal atrophy, which occurs far from the cyst, is an emerging new complication of NCC. Evaluation of molecular pathways in brain regions close to and distant from the cyst could offer insight into this pathology. Methods Rats were inoculated intracranially with T. solium oncospheres. After 4 months, RNA was extracted from brain tissue samples in rats with NCC and uninfected controls, and cDNA was generated. Expression of 38 genes related to different molecular pathways involved in the inflammatory response and healing was assessed by RT-PCR array. Results Inflammatory cytokines IFN-?, TNF-?, and IL-1, together with TGF-? and ARG-1, were overexpressed in tissue close to the parasite compared to non-infected tissue. Genes for IL-1A, CSF-1, FN-1, COL-3A1, and MMP-2 were overexpressed in contralateral tissue compared to non-infected tissue. Conclusions The viable cysticerci in the rat model for NCC is characterized by increased expression of genes associated with a proinflammatory response and fibrosis-related proteins, which may mediate the chronic state of infection. These pathways appear to influence regions far from the cyst, which may explain the emerging association between NCC and hippocampal atrophy. © 2021 Carmen-Orozco et al.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
From the Andes to the desert: 16S rRNA metabarcoding characterization of aquatic bacterial communities in the Rimac river, the main source of water for Lima, Peru
No full textThe Rimac river is the main source of water for Lima, Peru's capital megacity. The river is constantly affected by different types of contamination including mine tailings in the Andes and urban sewage in the metropolitan area. In this work, we aim to produce the first characterization of aquatic bacterial communities in the Rimac river using a 16S rRNA metabarcoding approach which would be useful to identify bacterial diversity and potential understudied pathogens. We report a lower diversity in bacterial communities from the Lower Rimac (Metropolitan zone) in comparison to other sub-basins. Samples were generally grouped according to their geographical location. Bacterial classes Alphaproteobacteria, Bacteroidia, Campylobacteria, Fusobacteriia, and Gammaproteobacteria were the most frequent along the river. Arcobacter cryaerophilus (Campylobacteria) was the most frequent species in the Lower Rimac while Flavobacterium succinicans (Bacteroidia) and Hypnocyclicus (Fusobacteriia) were the most predominant in the Upper Rimac. Predicted metabolic functions in the microbiota include bacterial motility and quorum sensing. Additional metabolomic analyses showed the presence of some insecticides and herbicides in the Parac-Upper Rimac and Santa Eulalia-Parac sub-basins. The dominance in the Metropolitan area of Arcobacter cryaerophilus, an emergent pathogen associated with fecal contamination and antibiotic multiresistance, that is not usually reported in traditional microbiological quality assessments, highlights the necessity to apply next-generation sequencing tools to improve pathogen surveillance. We believe that our study will encourage the integration of omics sciences in Peru and its application on current environmental and public health issues. © 2021 Romero et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Stability and expansivity of tent map
No full textWe discuss the stability and the expansivity of the tent map f: [0, 1] ? [0, 1] defined by f(x) = 2 min{x, 1 ? x} for 0 ? x ? 1. Indeed, we show that f is neither topologically stable nor orbit shift topologically stable nor countably-expansive but is cw-topologically stable, orbit shift cw-expansive, and orbit shift ?-persistent. © 2020 American Mathematical SocietyConsejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Development of the phase composition and the properties of Ti2AlC and Ti3AlC2 MAX-phase thin films – A multilayer approach towards high phase purity
No full textMAX phase thin films have been synthesized by thermal treatment of a Ti-Al-C multilayer system. The preparation of the multilayer system was carried out via magnetron sputtering. Based on the thickness ratio among the individual nanoscale monolayers (Ti, Al, C), the resulting MAX phase stoichiometry can be controlled. This paper describes the synthesis of both Ti2AlC and Ti3AlC2 MAX phases from the same precursor multilayer system which is composed of a sequence of Ti/Al/C pure elemental single layers with thicknesses of 14, 6, and 3.5 nm, respectively. This sequence is repeated 22 times with a total thickness of around 500 nm. Rapid thermal treatment tests were performed to study the phase development. The Ti2AlC MAX phase forms in a temperature range below 850 °C, whereas the Ti3AlC2 MAX phase starts to form at temperatures above 850 °C and reaches its highest phase purity at 950 °C. The thin film structures were studied by X-ray diffraction and Raman spectroscopy. Furthermore, the electrical and mechanical properties were investigated to gain more insights regarding the phase transformation and their influence on the thin film properties. © 2020 Elsevier B.V.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
The complete mitochondrial genome of the oleaginous microalgae Ankistrodesmus falcatus strain UCP001 from the Peruvian Amazon
No full textAnkistrodesmus falcatus strain UCP001 is a native oleaginous microalgae isolated from the Peruvian Amazon basin. In this study we sequenced, de novo assembled, and functionally annotated the complete mitochondrial genome of the native oleaginous microalgae Ankistrodesmus falcatus strain UCP001 (Accesion number MT701044). This mitogenome is a typical circular double stranded DNA molecule of 41,048 bp in total length with G + C content of 37.4%. The mitogenome contains 49 genes, including 18 protein coding genes, 5 ribosomal (rRNA) genes and 26 transfer RNA (tRNA) genes. A phylogenetic analysis of 18 microalgae species indicated that Ankistrodesmus falcatus strain UCP001 was closely related to Ourococcus multisporus and Raphidocelis subcapitata. The complete mitochondrial genome sequence of Ankistrodesmus falcatus strain UCP001 enriches genomic resources of oleaginous native microalgae from the Peruvian Amazon for further basic and applied research. © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Kinetics drying of blackberry bagasse and degradation of anthocyanins and bioactive properties
No full textThe process of drying food is necessary to preserve it; however, some bioactive compounds can be degraded during drying process. In this work, the convective drying process of Peruvian blackberry bagasse and the degradation of anthocyanins, total phenolic content (TPC), and antioxidant capacity (AC) were studied. The logarithmic model fitted well to the data and could predict the process, showing that 6 h of drying at 90?C is enough to reach equilibrium moisture. Anthocyanin degradation followed a first-order kinetic model with reaction rate constant between 5.45 × 10?2 ± 4.68 × 10?3 and 1.21 × 10?1 ± 2.31 × 10?2 h?1, and activation energy of 25.11 kJ/mol. The highest retention (84.38%) of anthocyanins was obtained in 1 h at 50?C and the highest degradation (68.54%) in 6 h at 90?C. The TPC and AC increased with the drying time and temperature due to the increased water evaporation. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Comment on “Genetic variants and source of introduction of SARS-CoV-2 in South America”
No full textI read with great interest a recent study by Poterico and Mestanza who described mutations in 30 SARS‐CoV‐2 genomes from South American countries (Argentina, Brazil, Chile, Colombia, Ecuador, and Peru). Next‐generation sequencing (NGS) technologies have accelerated genomic and metagenomic studies providing affordable tools to obtain pathogen genomes and improving diagnosis and surveillance efforts. However, many downstream analyses after assembling the genomes are impacted by low‐quality sequences and sequence contamination, which could lead to wrong conclusion.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte