29 research outputs found

    Wind Speed as a Dominant Source of Periodicities in Reported Emission Rates of Volcanic SO2

    Get PDF
    Volcanoes have been found to display periodicities or cyclic trends in a wide range of phenomena. These include the eruptive activity itself, but also in the time series of geophysical and geochemical monitoring data such as volcanic degassing. Here, we test the existence of periodicities of volcanic degassing at 32 volcanoes using the time series of sulfur dioxide (SO2) emission rates from data of the Network of Volcanic and Atmospheric Change (NOVAC). We use the Lomb-Scargle periodogram to analyze the SO2 data which allows efficient computation of a Fourier-like power spectrum from unevenly sampled data. We were able to calculate False-Alarm Probabilities in 28 of the 32 volcanoes, and we identified significant periodicities in the SO2 emission rates in 17 of the 28 volcanoes. However, we find that most of these periodicities are also present in the plume speeds used to determine SO2 emission rates. Periodicities at about 30–70, ∼120, and ∼180\ua0days were identified at volcanoes located between 16\ub0N and 16\ub0S and are related to intraseasonality and interseasonality in global trade winds and not volcanic in origin. Periodicities between 30 and 70\ua0days in both plume speed and SO2 emission rates are associated to the Madden-Julian Oscillation that is responsible for intraseasonal variability in the tropical atmosphere. Our study highlights the importance of using local wind data for deriving realistic SO2 emissions and the identification of short-term periodicity in volcanic behavior

    Evolution of the 2015 Cotopaxi Eruption Revealed by Combined Geochemical & Seismic Observations

    Get PDF
    Through integration of multiple data streams to monitor volcanic unrest scientists are able to make more robust eruption forecast and to obtain a more holistic interpretation of volcanic systems. We examined gas emission and gas geochemistry and seismic and petrologic data recorded during the 2015 unrest of Cotopaxi (Ecuador) in order to decipher the origin and temporal evolution of this eruption. Identification of families of similar seismic events and the use of seismic amplitude ratios reveals temporal changes in volcanic processes. SO2 (300 to 24,000 t/d), BrO/SO2 (5–10 7 10−5), SO2/HCl (5.8 \ub1 4.8 and 6.6 \ub1 3.0), and CO2/SO2 (0.6 to 2.1) measured throughout the eruption indicate a shallow magmatic source. Bulk ash and glass chemistry indicate a homogenous andesitic (SiO2 wt % = 56.94 \ub1 0.25) magma having undergone extensive S-exsolution and degassing during ascent. These data lead us to interpret this eruption as a magma intrusion and ascend to shallow levels. The intrusion progressively interacted with the hydrothermal system, boiled off water, and produced hydromagmatic explosions. A small volume of this intrusion continued to fragment and produced episodic ash emissions until it was sufficiently degassed and rheologically stiff. Based on the 470 kt of measured SO2 we estimate that ~65.3 7 106 m3 of magma were required to supply the emitted gases. This volume exceeds the volume of erupted juvenile material by a factor of 50. This result emphasizes the importance of careful monitoring of Cotopaxi to identify the intrusion of a new batch of magma, which could rejuvenate the nonerupted material

    Investigator choice of standard therapy versus sequential novel therapy arms in the treatment of relapsed follicular lymphoma (REFRACT): study protocol for a multi-centre, open-label, randomised, phase II platform trial

    Get PDF
    BackgroundRelapsed or refractory follicular lymphoma (rrFL) is an incurable disease associated with shorter remissions and survival after each line of standard therapy. Many promising novel, chemotherapy-free therapies are in development, but few are licensed as their role in current treatment pathways is poorly defined. MethodsThe REFRACT trial is an investigator-initiated, UK National Cancer Research Institute, open-label, multi-centre, randomised phase II platform trial aimed at accelerating clinical development of novel therapies by addressing evidence gaps. The first of the three sequential novel therapy arms is epcoritamab plus lenalidomide, to be compared with investigator choice standard therapy (ICT). Patients aged 18 years or older with biopsy proven relapsed or refractory CD20 positive, grade 1-3a follicular lymphoma and assessable disease by PET-CT are eligible. The primary outcome is complete metabolic response by PET-CT at 24 weeks using the Deauville 5-point scale and Lugano 2014 criteria. Secondary outcomes include overall metabolic response, progression-free survival, overall survival, duration of response, and quality of life assessed by EQ-5D-5 L and FACT-Lym. The trial employs an innovative Bayesian design with a target sample size of 284 patients: 95 in the ICT arm and 189 in the novel therapy arms. Discussion:Whilst there are many promising novel drugs in early clinical development for rrFL, understanding the relative efficacy and safety of these agents, and their place in modern treatment pathways, is limited by a lack of randomised trials and dearth of published outcomes for standard regimens to act as historic controls. Therefore, the aim of REFRACT is to provide an efficient platform to evaluate novel agents against standard therapies for rrFL. The adaptive Bayesian power prior methodology design will minimise patient numbers and accelerate trial delivery. Trial registration: ClinicalTrials.gov: NCT05848765; 08-May-2023. EudraCT: 2022-000677-75; 10-Feb-2022

    Global monitoring of volcanic SO2 degassing with unprecedented resolution from TROPOMI onboard Sentinel-5 Precursor

    Get PDF
    Over the last four decades, space-based nadir observations of sulfur dioxide (SO2 ) proved to be a key data source for assessing the environmental impacts of volcanic emissions, for monitoring volcanic activity and early signs of eruptions, and ultimately mitigating related hazards on local populations and aviation. Despite its importance, a detailed picture of global SO 2 daily degassing is difficult to produce, notably for lower-tropospheric plumes, due largely to the limited spatial resolution and coverage or lack of sensitivity and selectivity to SO2 of current (and previous) nadir sensors. We report here the first volcanic SO2 measurements from the hyperspectral TROPOspheric Monitoring Instrument (TROPOMI) launched in October 2017 onboard the ESA’s Sentinel-5 Precursor platform. Using the operational processing algorithm, we explore the benefit of improved spatial resolution to the monitoring of global volcanic degassing. We find that TROPOMI surpasses any space nadir sensor in its ability to detect weak degassing signals and captures day-to-day changes in SO2 emissions. The detection limit of TROPOMI to SO2 emissions is a factor of 4 better than the heritage Aura/Ozone Monitoring Instrument (OMI). Here we show that TROPOMI SO2 daily observations carry a wealth of information on volcanic activity. Provided with adequate wind speed data, temporally resolved SO2 fluxes can be obtained at hourly time steps or shorter. We anticipate that TROPOMI SO2 data will help to monitor global volcanic daily degassing and better understand volcanic processes and impacts

    Synoptic analysis of a decade of daily measurements of SO2 emission in the troposphere from volcanoes of the global ground-based Network for Observation of Volcanic and Atmospheric Change

    Get PDF
    Volcanic plumes are common and far-reaching manifestations of volcanic activity during and between eruptions. Observations of the rate of emission and composition of volcanic plumes are essential to recognize and, in some cases, predict the state of volcanic activity. Measurements of the size and location of the plumes are important to assess the impact of the emission from sporadic or localized events to persistent or widespread processes of climatic and environmental importance. These observations provide information on volatile budgets on Earth, chemical evolution of magmas, and atmospheric circulation and dynamics. Space-based observations during the last decades have given us a global view of Earth's volcanic emission, particularly of sulfur dioxide (SO2). Although none of the satellite missions were intended to be used for measurement of volcanic gas emission, specially adapted algorithms have produced time-averaged global emission budgets. These have confirmed that tropospheric plumes, produced from persistent degassing of weak sources, dominate the total emission of volcanic SO2. Although space-based observations have provided this global insight into some aspects of Earth's volcanism, it still has important limitations. The magnitude and short-term variability of lower-atmosphere emissions, historically less accessible from space, remain largely uncertain. Operational monitoring of volcanic plumes, at scales relevant for adequate surveillance, has been facilitated through the use of ground-based scanning differential optical absorption spectrometer (ScanDOAS) instruments since the beginning of this century, largely due to the coordinated effort of the Network for Observation of Volcanic and Atmospheric Change (NOVAC). In this study, we present a compilation of results of homogenized post-analysis of measurements of SO2 flux and plume parameters obtained during the period March 2005 to January 2017 of 32 volcanoes in NOVAC. This inventory opens a window into the short-term emission patterns of a diverse set of volcanoes in terms of magma composition, geographical location, magnitude of emission, and style of eruptive activity. We find that passive volcanic degassing is by no means a stationary process in time and that large sub-daily variability is observed in the flux of volcanic gases, which has implications for emission budgets produced using short-term, sporadic observations. The use of a standard evaluation method allows for intercomparison between different volcanoes and between ground- and space-based measurements of the same volcanoes. The emission of several weakly degassing volcanoes, undetected by satellites, is presented for the first time. We also compare our results with those reported in the literature, providing ranges of variability in emission not accessible in the past. The open-access data repository introduced in this article will enable further exploitation of this unique dataset, with a focus on volcanological research, risk assessment, satellite-sensor validation, and improved quantification of the prevalent tropospheric component of global volcanic emission

    Mortality Among Adults With Cancer Undergoing Chemotherapy or Immunotherapy and Infected With COVID-19

    Get PDF
    Importance: Large cohorts of patients with active cancers and COVID-19 infection are needed to provide evidence of the association of recent cancer treatment and cancer type with COVID-19 mortality. // Objective: To evaluate whether systemic anticancer treatments (SACTs), tumor subtypes, patient demographic characteristics (age and sex), and comorbidities are associated with COVID-19 mortality. // Design, Setting, and Participants: The UK Coronavirus Cancer Monitoring Project (UKCCMP) is a prospective cohort study conducted at 69 UK cancer hospitals among adult patients (≥18 years) with an active cancer and a clinical diagnosis of COVID-19. Patients registered from March 18 to August 1, 2020, were included in this analysis. // Exposures: SACT, tumor subtype, patient demographic characteristics (eg, age, sex, body mass index, race and ethnicity, smoking history), and comorbidities were investigated. // Main Outcomes and Measures: The primary end point was all-cause mortality within the primary hospitalization. // Results: Overall, 2515 of 2786 patients registered during the study period were included; 1464 (58%) were men; and the median (IQR) age was 72 (62-80) years. The mortality rate was 38% (966 patients). The data suggest an association between higher mortality in patients with hematological malignant neoplasms irrespective of recent SACT, particularly in those with acute leukemias or myelodysplastic syndrome (OR, 2.16; 95% CI, 1.30-3.60) and myeloma or plasmacytoma (OR, 1.53; 95% CI, 1.04-2.26). Lung cancer was also significantly associated with higher COVID-19–related mortality (OR, 1.58; 95% CI, 1.11-2.25). No association between higher mortality and receiving chemotherapy in the 4 weeks before COVID-19 diagnosis was observed after correcting for the crucial confounders of age, sex, and comorbidities. An association between lower mortality and receiving immunotherapy in the 4 weeks before COVID-19 diagnosis was observed (immunotherapy vs no cancer therapy: OR, 0.52; 95% CI, 0.31-0.86). // Conclusions and Relevance: The findings of this study of patients with active cancer suggest that recent SACT is not associated with inferior outcomes from COVID-19 infection. This has relevance for the care of patients with cancer requiring treatment, particularly in countries experiencing an increase in COVID-19 case numbers. Important differences in outcomes among patients with hematological and lung cancers were observed

    A thematic literature unit : developing children's understanding of culture, cultural identity, and diverse cultural perspectives

    Get PDF
    In a fast paced technological world, global and multicultural issues are in the forefront of every day life. Children need to develop a more global understanding, acceptance and knowledge of themselves and others. This project explores the use of children's literature to develop the concepts of culture, cultural awareness, cultural identity, and diverse cultural perspectives. A thematic literature unit suitable for eleven to fourteen year olds has been designed to enable children to explore these concepts by reading and responding to a variety of children's literature. The literature serves as a springboard for discussion of these concepts and helps children look at themselves and others in new ways. In this project, the writer describes the process of designing a thematic literature unit with the goal of developing children's global understanding, acceptance and knowledge of themselves and others. This includes the selection of learning outcomes, learning resources, learning experiences and the development of assessment and evaluation tools. Then a framework has been developed to demonstrate the implementation of this thematic literature unit in an elementary classroom

    Using volcanic gases to understand open-vent volcanoes

    No full text
    Open-vent volcanoes include the most active on Earth and are characterized by their persistent outgassing and the occurrence of moderate explosive activity between major eruptions. Forecasting eruptive activity at open-vent volcanoes is particularly challenging owing to the small changes in geophysical parameters which typically proceed eruptions. Changes in the emission rate and composition of plume gases however, presents a critical opportunity to detect changes before the arrival of magma at the surface. Subsequent identification of periodic trends implies that periodicities are an underlying component of volcanic plume degassing which could provide fundamental insights into the processes controlling volcanic degassing, and in turn, aid our ability to forecast eruptions. One of the only ways to obtain a continuous record of the plume gas is by ground-based remote sensing using UV-spectrometers where the favoured approach for quantifying emissions of SO2 is by Differential Optical Absorption Spectroscopy, a technique based on the Beer-Lambert-Bouguer law which relates the attenuation of light to properties of the material through which it has travelled. The challenge for volcanologists arises due to the absorption signatures of several trace gases in the spectra, which are present in various unknown quantities, many of which absorb light at shared wavelengths. To isolate the absorption due to SO2 from that of other trace gases, as well as atmospheric and instrumentals effects, a complex fitting routine is required where expertise is not only essential for the selection of suitable fit parameters but also for visual inspection of the fit results. Here, I present a novel approach which instead exploits the well-defined spatial frequencies in UV spectra. Although the wavelength ranges of trace gas absorption cross sections overlap, the occurrence of their narrow-band absorption features is not uniform and when viewed in the wavenumber domain their absorption signatures are distinct. I present a simple linear model to quantify SO2 absorption by detection of its wavelet transform and demonstrate its ability to return expected slant column densities of SO2 which are comparable to those achieved using a traditional DOAS algorithm. I further capitalise on the spatial frequencies contained in the recorded UV spectra to track volcanic SO2 without the need for external reference spectra. By correlating spectra in the frequency domain, I provide a simple means to identify spectra which contain the absorption signature of the volcanic plume. Use of wavelet coherence provides an alternative means to verify fit results and to establish a suitable wavelength range for spectral analysis. I test the possibility to analyse spectra for trace gases which are typically present at much lower concentrations, and explore the use of the linear model to quantify bromine monoxide (BrO) and chlorine dioxide (OClO), which offer the potential to detect magma emplaced at shallow depth. Finally, I test the existence of periodicities in the SO2 emission rate from a range of volcanoes with vastly different characteristics. I use time series data acquired by the Network of Volcanic and Atmospheric Change (NOVAC) and the Lomb-Scargle periodogram, to identify significant periodicities in the SO2 emission rates of 17 of the 28 volcanoes analysed. However, I find that most of these periodicities are also present in the plume speeds used to determine SO2 emission rates and are related to intra- and inter-seasonality in global trade winds and not volcanic in origin.Doctor of Philosoph

    The ICE LAW Project, Two Years On

    Get PDF
    publishedVersio
    corecore