Search results for "Ande"
showing 10 items of 5018 documents
Analysis of psychoactive substances in water by information dependent acquisition on a hybrid quadrupole time-of-flight mass spectrometer.
2016
Emerging drugs of abuse, belonging to many different chemical classes, are attracting users with promises of “legal” highs and easy access via internet. Prevalence of their consumption and abuse through wastewater-based epidemiology can only be realized if a suitable analytical screening procedure exists to detect and quantify them in water. Solid-phase extraction and ultra-high performance liquid chromatography quadrupole time-of-flight-mass spectrometry (UHPLC–QqTOF–MS/MS) was applied for rapid suspect screening as well as for the quantitative determination of 42 illicit drugs and metabolites in water. Using this platform, we were able to identify amphetamines, tryptamines, piperazines, p…
Noble gas magmatic signature of the Andean Northern Volcanic Zone from fluid inclusions in minerals
2021
Trace volatile elements like He are key for understanding the mantle source signature of magmas and to better constrain the relative roles of subduction and crustal processes to the variability of along-arc chemical and isotopic signatures of magmatic fluids. Here we report on noble gas abundances and isotopic data of Fluid Inclusions (FIs) in eruptive products and/or fumarolic gases from the Colombia-Ecuador segment of Andean Northern Volcanic Zone (NVZ). FIs in olivine phenocrysts from Ecuador (El Reventador, Cotopaxi and Tungurahua) yield air-normalized corrected He-3/He-4 ratios of 7.0-7.4 R-A, within the MORB range (8 +/- 1 R-A). With exception of the Cotopaxi lavas (opx = 50 km at the…
Extensive, water-rich magma reservoir beneath southern Montserrat
2016
South Soufriere Hills and Soufriere Hills volcanoes are two km apart at the southern end of the island of Montserrat, West Indies. Their magmas are distinct geochemically, despite these volcanoes having been active contemporaneously at 131-129 ka. We use the water content of pyroxenes and melt inclusion data to reconstruct the bulk water contents of magmas and their depth of storage prior to eruption. Pyroxenes contain up to 281 ppm H2O, with significant variability between crystals and from core to rim in individual crystals. The Al content of the enstatites from Soufriere Hills Volcano (SHV) is used to constrain melt-pyroxene partitioning for H2O. The SHV enstatite cores record melt water…
Antisana volcano: A representative andesitic volcano of the eastern cordillera of Ecuador: Petrography, chemistry, tephra and glacial stratigraphy
2017
Antisana volcano is representative of many active andesitic strato-volcanoes of Pleistocene age in Ecuador's Eastern Cordillera. This study represents the first modern geological and volcanological investigation of Antisana since the late 1890's; it also summarizes the present geochemical understanding of its genesis. The volcano's development includes the formation and destruction of two older edifices (Antisana I and II) during some 400 + ka. Antisana II suffered a sector collapse about 15,000 years ago which was followed by the birth and growth of Antisana III. During its short life Antisana III has generated >= 50 eruptions of small to medium intensity, often associated with andesitic t…
The Synergistic Impacts of Anthropogenic Stressors and COVID-19 on Aquaculture: A Current Global Perspective
2021
13 pages, 6 figures, 2 tables.-- This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License
Occurrence, distribution, and risk assessment of pharmerciuticals in wastewater and open surface drains of peri-urban areas: Case study of Juja town,…
2020
Abstract The occurrence of Active Pharmaceutical Ingredients (APIs) in the environment is becoming a major area of concern due to their undesirable effects on non-target organisms. This study investigated the occurrence and risk of contamination by five antibiotics and three antiretrovirals drugs in a fast-growing peri-urban area in Kenya, with inadequate sewer system coverage. Due to poor sewage connectivity and poorly designed decentralized systems, wastewater is directly released in open drains. Water and sediment samples were collected from open surface water drains, while wastewater samples were collected from centralized wastewater treatment plants (WWTP). Solid-phase extraction and u…
FLEX/S3 Tandem Mission Performance Assessment: Evolution of the End-to-End Simulator Flex-E
2018
An End-to-end simulator (E2ES) is a tool to evaluate the performance of a satellite mission. Once a mission is approved for operation, E2ES evolves during Phase C/D to become a supporting tool for the development and validation of the ground data processor, as well as for simulating data sets to test the Prototype and Operational Processors. FLEX-E is the E2ES of the FLEX/Sentinel-3 tandem mission, which was selected in 2015 as ESA's eighth Earth Explorer. The FLEX-E evolution implies the consolidation of all the retrieval algorithms (e.g. fluorescence, reflectance, biophysical variables), the implementation of new scientific developments, as well the improvement of the co-registration proc…
Palaeoecological implications of Neanderthal occupation at Unit Xb of El Salt (Alcoi, eastern Spain) during MIS 3 using small mammals proxy
2018
Nearly 250 small mammal remains from Unit Xb of El Salt Middle Palaeolithic site have been studied in order to reconstruct the palaeoecological conditions during a phase of Neanderthal occupation in this locality at 52.3 ± 4.6 ka. A total of 7rodents (Microtus arvalis, M. agrestis, M. (Terricola) duodecimcostatus, Microtus (Iberomys) cabrerae, Arvicola sapidus, Eliomys quercinus and Apodemus sylvaticus), 4 insectivores (Erinaceus cf. europaeus, Crocidura sp., Sorex sp. and Talpidae indet.) and 1 lagomorph (Oryctolagus cf. cuniculus) have been identified. Applying the Mutual Ecogeographic Range and Habitat Weighting methods, Unit Xb may correspond to a relatively cold (−3.3 °C in comparison …
Symbolic use of marine shells and mineral pigments by Iberian Neandertals 115,000 years ago.
2018
U-Th dating of archaeological deposits of Cueva de los Aviones provides evidence for Neandertal symbolism 115,000 years ago.
Hunted or Scavenged Neanderthals? Taphonomic Approach to Hominin Fossils with Carnivore Damage
2017
Carnivore damage on Neanderthal fossils is a much more common taphonomic modification than previously thought. Its presence could have different explanations, including predatory attacks or scavenging scenarios, which are both situations with important implications concerning Neanderthal behaviour. In the present paper, we analyse several Neanderthal hominin fossils from a taphonomic and forensic perspective in order to infer the nature of the modifications observed on the bone surfaces. Fossils displaying carnivore modifications from Spain, Germany, Belgium and Greece are evaluated from a taphonomic perspective for the first time in a significant sample of hominin specimens. Our results sh…