Search results for "hazards"

The bridge volcanic LIdar-BILLI: A review of data collection and processing techniques in the Italian most hazardous volcanic areas

2020

Volcanologists have demonstrated that carbon dioxide (CO2) fluxes are precursors of volcanic eruptions. Controlling volcanic gases and, in particular, the CO2 flux, is technically challenging, but we can retrieve useful information from magmatic/geological process studies for the mitigation of volcanic hazards including air traffic security. Existing techniques used to probe volcanic gas fluxes have severe limitations such as the requirement of near-vent in situ measurements, which is unsafe for operators and deleterious for equipment. In order to overcome these limitations, a novel range-resolved DIAL-Lidar (Differential Absorption Light Detection and Ranging) has been developed as part of…

Magmatic gas percolation through the old lava dome of El Misti volcano

2017

International audience; The proximity of the major city of Arequipa to El Misti has focused attention on the hazards posed by the active volcano. Since its last major eruption in the fifteenth century, El Misti has experienced a series of modest phreatic eruptions and fluctuating fumarolic activity. Here, we present the first measurements of the compositions of gas emitted from the lava dome in the summit crater. The gas composition is found to be fairly dry with a H2O/SO2 molar ratio of 32 ± 3, a CO2/SO2 molar ratio of 2.7 ± 0.2, a H2S/SO2 molar ratio of 0.23 ± 0.02 and a H2/SO2 molar ratio of 0.012 ± 0.002. This magmatic gas signature with minimal evidence of hydrothermal or wall rock int…

Rapid laccolith intrusion driven by explosive volcanic eruption

2016

Magmatic intrusions and volcanic eruptions are intimately related phenomena. Shallow magma intrusion builds subsurface reservoirs that are drained by volcanic eruptions. Thus, the long-held view is that intrusions must precede and feed eruptions. Here we show that explosive eruptions can also cause magma intrusion. We provide an account of a rapidly emplaced laccolith during the 2011 rhyolite eruption of Cordón Caulle, Chile. Remote sensing indicates that an intrusion began after eruption onset and caused severe (>200 m) uplift over 1 month. Digital terrain models resolve a laccolith-shaped body ∼0.8 km3. Deformation and conduit flow models indicate laccolith depths of only ∼20–200 m and ov…

Helium and CO2 soil gas emission from Santorini (Greece)

1994

Soil gas investigation is a useful tool to detect active faults. The sudden appearance of soil gas anomalies in zones of deep-reaching faults represents a promising potential precursor of earthquakes and volcanic eruptions. In volcanic areas the development of soil gas monitoring techniques is particularly important, as they can represent, together with remote sensing techniques, the only geochemical methods that can be safely applied during volcanic unrest, when it becomes impossible or too dangerous to sample crater fumaroles. A soil gas survey was carried out in June 1993 at the main island of Thera, in the Santorini volcanic complex. CO2 flux and CO2 and helium concentrations were measu…

317 Role of integrins in the metastatic spread of high-grade serous ovarian cancer

2021

Introduction/Background* In high-grade serous ovarian cancer (HGSOC) an early intraperitoneal metastatic spread is common which determines the therapeutical approach and prognosis. Integrins may be involved in metastatic spread of HGSOC. In this study, integrin expression was examined in primary tumour and metastases of HGSOC. Methodology The expression of integrin α2, α4, α5, α6, and β1 was assessed by immunostaining in tumour samples of the ovary, omentum, and peritoneum of each patient. Differences in integrin expression among tumour localisations and their association with clinicopathological parameters were examined by Fisher’s exact test. The impact of integrin expression on progressi…

Climats tropicaux d'aujourd'hui à demain : variabilité et changements

2008

Present and future tropical climates : their climate variability and their climate changes The oriffttality of tropical climates is re-examined under the light of climate variability and climate change, both present and future . The interannual variability of rainfall is on average larger in the tropics than in the extra-tropics, but it is also spatially more contrasted. Human communities have often responded to this constraint through efficient coping strategies. The regions showing the most variable climate do not necessarily have lower population densities, an indication that in the long run variability is not decisive. However, the recent demographic growth of these regions is often low…

Goodness-of-fit tests for parametric excess hazard rate models with covariates

2017

In this paper we propose a general methodology for testing the null hypothesis that an excess hazard rate model, with or without covariates, belongs to a parametric family. Estimating the excess hazard rate function parametrically through the maximum likelihood method and non-parametrically (or semi-parametrically) we build a discrepancy process which is shown to be asymptotically Gaussian under the null hypothesis. Based on this result we are able to build some statistical tests in order to decide wether or not the null hypothesis is acceptable. We illustrate our results by the construction of chi-square tests which the behavior is studied through a Monte-Carlo study. Then the testing proc…

Hospitalization for self-harm during the early months of the COVID-19 pandemic in France: A nationwide retrospective observational cohort study

2021

ABSTRACT Background Little is known to date about the impact of COVID-19 pandemic on self-harm. Methods The number of hospitalizations for self-harm (ICD-10 codes X60-X84) in France from 1st January to 31st August 2020 (including a two-month confinement) was compared to the same periods in 2017–2019. Statistical methods comprised Poisson regression, Cox regression and Student's t-test, plus Spearman's correlation test relating to spatial analysis of hospitalizations. Outcomes There were 53,583 self-harm hospitalizations in France during January to August 2020. Compared to the same period in 2019, this represents an overall 8·5% decrease (Relative Risk [95% Confidence Interval] = 0·91 [0·90–…

Air pollution, chronic smoking, and mortality.

2019

Size and survival of the hospitality industry: The case of Spain

2020

The aim of this study is to analyse the determinants of survival of the hospitality industry. The study pays particular attention to the size of the enterprises since the majority of Spanish hospitality enterprises are microenterprises. Two approaches are considered. The first approach uses a binary choice model to analyse the determinants of survival probability as well as the Blinder–Oaxaca decomposition, proposed by Yun (2004), to quantify the difference between enterprises according to their size and what proportion of this difference is due to observed factors or unobserved factors. The second approach is a survival analysis, carried out through the Cox proportional hazard model, whic…