Search results for " Monitoring"

Main intrinsic factors driving land grabbing in the African countries’ agro-food industry

2022

Land grabbing is a phenomenon that has spread widely over the last two decades and which involves rich and emerging countries and international companies as protagonists in the large-scale acquisition of land in developing countries. Through the development of an econometric model that takes into account the annual size of land grabbing in the African countries, the research aims to understand the main intrinsic factors, linked to the hosting countries, that guide the large-scale acquisition of land by foreign investors. Results show that the presence of a high debt towards foreign organisations, the high availability of virgin lands, the strong vocation of the hosting country for the culti…

Effects of Two Instructional Procedures on Spanish University Students’ Comprehension Monitoring when Reading Science Texts in English

2015

Abstract Two instructional approaches on comprehension monitoring in English as FL are contrasted. Although using the same materials (elementary science texts), one of them is based on tasks focusing on vocabulary and grammar, and the other one is based on main ideas identification and textual coherence. The English proficiency level was controlled and comprehension monitoring measures were obtained in the pretest and the posttest using embedded micro and macro-structural inconsistencies in texts. Results showed that teaching students to read in order to understand main ideas and to elaborate the text macrostructure produce better results than focusing attention on discourse low-level compo…

The Contributions of Language Skills and Comprehension Monitoring to Chinese Reading Comprehension: A Longitudinal Investigation

2021

This study examined how vocabulary, syntactic knowledge, and orthographic knowledge are related to comprehension monitoring and whether comprehension monitoring mediates the relations between these language skills and reading comprehension. Eighty-nine Chinese children were assessed on their vocabulary, syntactic knowledge, orthographic knowledge, and comprehension monitoring in Grade 1. Their reading comprehension skills were assessed in Grade 1 and Grade 3. Results showed that in Grade 1, comprehension monitoring mediated the relations between vocabulary and syntactic knowledge and reading comprehension. For Grade 3 reading comprehension, syntactic knowledge in Grade 1 was the only signif…

THE NATURE AND SOURCE OF MAJOR MAGMATIC VOLATILES: OPEN-VENT DEGASSING VOLCANOES IN THE CENTRAL AMERICAN VOLCANIC ARC

Major volatiles play an important role in subduction zone magmatism, from magma generation in the mantle, to crustal ascent and evolution, until its dramatic expression during a volcanic eruption. In the attempt to add a piece of information on source and behavior of major volatiles in arc volcanism, I here report on the geochemistry of H2O, CO2, S and Cl in two volcanic systems in NW Nicaragua (Central America), San Cristóbal and Telica. The observational approach is based upon combination of some of the most recent techniques in volcanic gas monitoring and petrology. I here explore quiescent and eruptive degassing processes by combining both volcanic gas and melt inclusion approaches. Fie…

UVolc: A software platform for measuring volcanic SO2 fluxes

2012

We present here a novel stand-alone software platform, UVolc, for remotely sensed measurement of volcanic SO"2 emission rates. Such data are important diagnostics of activity conditions, with utility in forecasting measures. This code is made user friendly to enable volcanologists, who are not experts in the underlying physics of spectroscopy, to perform their own measurements. The program provides considerable reduction in errors and far greater operating flexibility than existing analogous code, which, unlike UVolc, can only interface with hardware no longer in manufacture. UVolc will be described here, including a presentation of data collected with this program in the field.

Turmoil at Turrialba Volcano (Costa Rica): Degassing and eruptive processes inferred from high-frequency gas monitoring

2016

OVSICORI Eruptive activity at Turrialba Volcano (Costa Rica) has escalated significantly since 2014, causing airport and school closures in the capital city of San José. Whether or not new magma is involved in the current unrest seems probable but remains a matter of debate as ash deposits are dominated by hydrothermal material. Here we use high‐frequency gas monitoring to track the behavior of the volcano between 2014 and 2015 and to decipher magmatic versus hydrothermal contributions to the eruptions. Pulses of deeply derived CO2‐rich gas (CO2/Stotal > 4.5) precede explosive activity, providing a clear precursor to eruptive periods that occurs up to 2 weeks before eruptions, which are acc…

Terminal Strombolian activity at Etna's central craters during summer 2012: The most CO2-rich volcanic gas ever recorded at Mount Etna

2016

By using a permanent network of multi-component gas analyzer systems (Multi-GAS), we report for the first time the H2O-CO2-SO2 composition of the volcanic gases emitted prior to, during, and after terminal Strombolian activity at Mount Etna's central craters (CCs). We show that the summer 2012 Strombolian episodes of the Bocca Nuova crater (BNC), the largest of Etna's CCs, are associated with the emission of the most CO2-rich gas measured at the volcano thus far. The BNC plume was particularly CO2-rich with CO2/SO2 up to 100, H2O/CO2 1 prevailed at the BNC and at other degassing vents such as Voragine and Northeast craters during Strombolian eruptions. Based on the results of numerical simu…

Practical Volcano-Independent Recognition of Seismic Events: VULCAN.ears Project

2021

Recognizing the mechanisms underlying seismic activity and tracking temporal and spatial patterns of earthquakes represent primary inputs to monitor active volcanoes and forecast eruptions. To quantify this seismicity, catalogs are established to summarize the history of the observed types and number of volcano-seismic events. In volcano observatories the detection and posterior classification or labeling of the events is manually performed by technicians, often suffering a lack of unified criteria and eventually resulting in poorly reliable labeled databases. State-of-the-art automatic Volcano-Seismic Recognition (VSR) systems allow real-time monitoring and consistent catalogs. VSR systems…

In situ Volcano Monitoring: Present and Future

2015

During the last couple of decades, volcanology has evolved significantly, allowing for an improved understanding of volcanic processes preceding, accompanying and following eruptive events. Key elements to these achievements are the huge amounts of high quality data being collected by networks of increasingly sensitive instruments deployed at active volcanoes. The diffusion of continuous, precise measurements of: (1) wide-band ground displacement; (2) flux and chemistry of volatile emissions; and (3) the spatio-temporal variations of potential fields (e.g., gravity) now permit imaging the mechanism that controls mass transfer underneath volcanoes to an unprecedented level of detail. Joined …

Diffuse soil CO2 degassing from Linosa island

2014

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