Search results for "Environment"
showing 10 items of 28487 documents
A model of degassing for Stromboli volcano
2010
International audience; A better understanding of degassing processes at open-vent basaltic volcanoes requires collection of new datasets of H2O–CO2–SO2 volcanic gas plume compositions, which acquisition has long been hampered by technical limitations. Here, we use the MultiGAS technique to provide the best-documented record of gas plume discharges from Stromboli volcano to date. We show that Stromboli's gases are dominated by H2O (48–98 mol%; mean, 80%), and by CO2 (2–50 mol%; mean, 17%) and SO2 (0.2–14 mol%; mean, 3%). The significant temporal variability in our dataset reflects the dynamic nature of degassing process during Strombolian activity; which we explore by interpreting our gas m…
Sulfur Degassing From Steam-Heated Crater Lakes: El Chichón (Chiapas, Mexico) and Víti (Iceland)
2018
The composition of the gases released by El Chichón (Chiapas, Mexico) and Víti (Askja volcano, Iceland) volcanic lakes is examined by Multi-GAS for the first time. Our results demonstrate that H2S and SO2 are degassed by these pH 2–3 lakes. We find higher CO2/H2S and H2/H2S ratios in the lakes' emissions (31–5,685 and 0.6–35, respectively) than in the fumarolic gases feeding the lakes (13–33 and 0.08–0.5, respectively), evidencing that only a fraction (0.2–5.4% at El Chichón) of the H2S(g) contributed by the subaquatic fumaroles ultimately reaches the atmosphere. At El Chichón, we estimate a H2S output from the crater lake of 0.02–0.06 t/day. Curiously, SO2 is also detected at trace levels …
Volcanic Plume CO2 Flux Measurements at Mount Etna by Mobile Differential Absorption Lidar
2017
Volcanic eruptions are often preceded by precursory increases in the volcanic carbon dioxide (CO2) flux. Unfortunately, the traditional techniques used to measure volcanic CO2 require near-vent, in situ plume measurements that are potentially hazardous for operators and expose instruments to extreme conditions. To overcome these limitations, the project BRIDGE (BRIDging the gap between Gas Emissions and geophysical observations at active volcanoes) received funding from the European Research Council, with the objective to develop a new generation of volcanic gas sensing instruments, including a novel DIAL-Lidar (Differential Absorption Light Detection and Ranging) for remote (e.g., distal) …
Ultraviolet imaging of volcanic plumes: A new paradigm in volcanology
2017
Ultraviolet imaging has been applied in volcanology over the last ten years or so. This provides considerably higher temporal and spatial resolution volcanic gas emission rate data than available previously, enabling the volcanology community to investigate a range of far faster plume degassing processes than achievable hitherto. To date, this has covered rapid oscillations in passive degassing through conduits and lava lakes, as well as puffing and explosions, facilitating exciting connections to be made for the first time between previously rather separate sub-disciplines of volcanology. Firstly, there has been corroboration between geophysical and degassing datasets at â1 Hz, expeditin…
Evolution of Seismicity During a Stalled Episode of Reawakening at Cayambe Volcano, Ecuador
2021
Cayambe Volcano is an ice-capped, 5,790 m high, andesitic-dacitic volcanic complex, located on the equator in the Eastern Cordillera of the Ecuadorian Andes. An eruption at Cayambe would pose considerable hazards to surrounding communities and a nationally significant agricultural industry. Although the only historically documented eruption was in 1785, it remains persistently restless and long-period (LP) seismicity has been consistently observed at the volcano for over 10 years. However, the sparse monitoring network, and complex interactions between the magmatic, hydrothermal, glacial, and tectonic systems, make unrest at Cayambe challenging to interpret. In June 2016 a seismic “crisis” …
Quantification of Platinum in Edible Mushrooms Using Voltammetric Techniques
2021
Edible mushrooms are a food source with interesting nutritional values. The chief objective of this research was to develop a consistent method for the quantitative ultra-trace analysis of Pt in mushrooms, which is complex because it cannot be readily quantified by common analytical procedures. This research is one of the first analytical methods to establish Pt amount in these vegetables. In this research, 28 different edible mushroom samples from Italy were investigated. Determination of Pt in mushrooms was completed using Differential Pulse Voltammetry (DPV). In this study, we applied the standard addition method because there are no certified reference mushrooms containing platinum grou…
Voluntary Private Investments Role in Pension System in Latvia
2021
Pension systems have become one of the main priorities for the national governments. Developed countries population is getting older by putting the pressure on the state budgets and work age people tax load. The current pension system in Latvia performs according to regulation of state compulsory unfunded pension scheme since 1996 and regulation of the state funded or accumulated pension scheme since 2001. The third pension system pillar is private voluntary pension schemes realized in form of people contributions into pension funds and life insurance policies. Aim of the research – deeper analyses of voluntary private investments as the pension system part and its development challenges in…
De la perception de la voyelle /y/ chez des apprenants polonais du français langue étrangère
2019
International audience; The main objective of this study is to test the perception of the vowel /y/ among the Polish learners of FLE, as it does not exist in their natural vowel system. We defend the hypothesis that optimal perception conditions can make the identification and acquisition of new sounds more intelligible.; L'objectif principal de cette étude est de tester la perception de la voyelle /y/ chez des apprenants polonais du FLE, celle-ci n'existant pas, en effet, dans leur système vocalique naturel. Nous défendons l'hypothèse selon laquelle des conditions de perception optimales peuvent rendre plus nettes, plus intelligibles, la perception et l'acquisition de sons nouveaux.
Characteristics of being hospitalized as a child with a new diagnosis of type 1 diabetes: a phenomenological study of children’s past and present exp…
2015
Background: Our understanding of children and childhood has changed over the last few decades, which may have an impact on children’s conditions in hospitals. Children’s rights have been strengthened by the “Convention on the Rights of the Child” and ward regulations. The aim of this Norwegian study was to identify potential characteristics of children's lived experience of being hospitalized diagnosed with type 1 diabetes today and from a retrospective view in the period 1950–1980, despite the many obvious external changes. Methods: This study presents a further analysis of data from two previous phenomenological studies. The first had a retrospective perspective, and the second assumed a …
What makes John move? Outdoor play physical environmental factors changing a child’s activity from sedentary to physically active: longitudinal mixed…
2021
Children’s low physical activity levels call for an investigation of what can promote activity for excessively sedentary children. The purpose of this longitudinal mixed-method case study in an early childhood education (ECE) environment was to observe one sedentary child’s free outdoor playtime in four seasons and determine the physical environmental factors changing his activity from sedentary to physically active. Systematic observation of video material and quantitative analysis were used to identify the most sedentary individual of the one ECE group. The child was named “John”. Qualitative analysis of John’s video material showed that during the four seasons he spent an average of 25% …