58 research outputs found
The Impact of Eruption Source Parameter Uncertainties on Ash Dispersion Forecasts During Explosive Volcanic Eruptions
Volcanic ash in the atmosphere is a hazard to aviation. To predict which areas of airspace are most likely to be affected by the presence of ash, Volcanic Ash Advisory Centers (VAACs) use observations and atmospheric dispersion models. These models are initialized with, among other parameters, a mass eruption rate (MER), which quantifies the emission rate into the atmosphere at the source. This influences the predicted spatialâtemporal evolution and concentration of the ash cloud. Different models are available to estimate MER from the volcanic plume height and some models also include the weather conditions (e.g., wind speed). The REFIR software tool uses timeâseries of plume height estimated from observations and weather data to provide estimates of MER through time. Here we present an updated version of REFIR that can now be used also to calculate MER for past eruptions and produce output parameters in a format suitable for use with the NAME dispersion model (UK Met OfficeâLondon VAAC). We also investigate how uncertainty in input parameters is propagated through to dispersion model output. Our results show that a +/â1 km uncertainty on a 6 km high plume can result in the affected area ranging by a factor of three between the minimum and maximum estimates. Additionally, we show that using windâaffected plume models results in affected areas that are five times larger than using noâwindâaffected models. This demonstrates the sensitivity of MER to the type of plume model chosen (noâwindâ vs. windâaffected)
Interactions between gas slug ascent and exchange flow in the conduit of persistently active volcanoes
Estimating the 3D shape of volcanic ash to better understand sedimentation processes and improve atmospheric dispersion modelling
Sensitivity of Volcanic Ash Dispersion Modelling to Input Grain Size Distribution Based on Hydromagmatic and Magmatic Deposits
The size distribution of volcanic ash is rarely measured in real time and Volcanic Ash Advisory Centres (VAACs) often rely on a default particle size distribution (PSD) to initialise their dispersion models when forecasting the movement of ash clouds. We conducted a sensitivity study to investigate the impact of PSD on model output and consider how best to apply default PSDs in operational dispersion modelling. Compiled grain size data confirm that, when considering particles likely to be in the distal ash cloud (< 125 µm diameter), magma composition and eruption size are the dominant controls on grain size distribution. Constraining the PSD is challenging but we find that the grain size of deposits from large hydromagmatic eruptions remains relatively constant with distance, suggesting that total (whole-deposit) grain size distributions (TGSDs) for these eruptions could be estimated from a few samples. We investigated the sensitivity of modelled ash mass loadings (in the air and on the ground) to input PSDs based on coarse to fine TGSDs from our dataset. We found clear differences between modelled mass loadings and the extent of the plume. Comparing TGSDs based on ground-only and ground-plus-satellite data for the Eyjafjallajökull 2010 eruption, we found that basing input PSDs on TGSDs from deposits alone (likely missing the finest particles) led to lower modelled peak ash concentrations and a smaller plume
The impact of particle shape on fall velocity:Implications for volcanic ash dispersion modelling
Aeolian Remobilisation of Volcanic Ash: Outcomes of a Workshop in the Argentinian Patagonia
During explosive volcanic eruptions, large quantities of tephra can be dispersed and deposited over wide areas. Following deposition, subsequent aeolian remobilisation of ash can potentially exacerbate primary impacts on timescales of months to millennia. Recent ash remobilisation events (e.g., following eruptions of CordĂłn Caulle 2011; Chile, and Eyjafjallajökull 2010, Iceland) have highlighted this to be a recurring phenomenon with consequences for human health, economic sectors, and critical infrastructure. Consequently, scientists from observatories and Volcanic Ash Advisory Centers (VAACs), as well as researchers from fields including volcanology, aeolian processes and soil sciences, convened at the San Carlos de Bariloche headquarters of the Argentinian National Institute of Agricultural Technology to discuss the ?state of the art? for field studies of remobilised deposits as well as monitoring, modeling and understanding ash remobilisation. In this article, we identify practices for field characterisation of deposits and active processes, including mapping, particle characterisation and sediment traps. Furthermore, since forecast models currently rely on poorly-constrained dust emission schemes, we call for laboratory and field measurements to better parameterise the flux of volcanic ash as a function of friction velocity. While source area location and extent are currently the primary inputs for dispersion models, once emission schemes become more sophisticated and better constrained, other parameters will also become important (e.g., source material volume and properties, effective precipitation, type and distribution of vegetation cover, friction velocity). Thus, aeolian ash remobilisation hazard and associated impact assessment require systematic monitoring, including the development of a regularly-updated spatial database of resuspension source areas.Fil: Jarvis, Paul A.. Universidad de Ginebra. Facultad de Ciencias. SecciĂłn de Ciencias de la Tierra; SuizaFil: Bonadonna, Costanza. Universidad de Ginebra. Facultad de Ciencias. SecciĂłn de Ciencias de la Tierra; SuizaFil: Dominguez, Lucia. Universidad de Ginebra. Facultad de Ciencias. SecciĂłn de Ciencias de la Tierra; SuizaFil: Forte, Pablo Brian. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Frischknecht, Corine. Universidad de Ginebra. Facultad de Ciencias. SecciĂłn de Ciencias de la Tierra; SuizaFil: Bran, Donaldo. Instituto Nacional de TecnologĂa Agropecuaria; ArgentinaFil: Aguilar, Rigoberto. No especifĂca;Fil: Beckett, Frances. No especifĂca;Fil: Elissondo, Manuela. SecretarĂa de Industria y MinerĂa. Servicio GeolĂłgico Minero Argentino; ArgentinaFil: Gillies, John. Desert Research Institute; Estados UnidosFil: Kueppers, Ulrich. Ludwig Maximilians Universitat; AlemaniaFil: Merrison, Jonathan. University Aarhus. Institut for Fysik Og Astronomi; DinamarcaFil: Varley, Nick. Universidad de Colima; MĂ©xicoFil: Wallace, Kristi L.. United States Geological Survey; Estados Unido
Mammography screening: views from women and primary care physicians in Crete
Background: Breast cancer is the most commonly diagnosed cancer among women and a leading cause of death from cancer in women in Europe. Although breast cancer incidence is on the rise worldwide, breast cancer mortality over the past 25 years has been stable or decreasing in some countries and a fall in breast cancer mortality rates in most European countries in the 1990s was reported by several studies, in contrast, in Greece have not reported these favourable trends. In Greece, the age-standardised incidence and mortality rate for breast cancer per 100.000 in 2006 was 81,8 and 21,7 and although it is lower than most other countries in Europe, the fall in breast cancer mortality that observed has not been as great as in other European countries. There is no national strategy for screening in this country. This study reports on the use of mammography among middleaged women in rural Crete and investigates barriers to mammography screening encountered by women and their primary care physicians.
Methods: Design: Semi-structured individual interviews. Setting and participants: Thirty women between 45â65
years of age, with a mean age of 54,6 years, and standard deviation 6,8 from rural areas of Crete and 28 qualified
primary care physicians, with a mean age of 44,7 years and standard deviation 7,0 serving this rural population.
Main outcome measure: Qualitative thematic analysis.
Results: Most women identified several reasons for not using mammography. These included poor knowledge
of the benefits and indications for mammography screening, fear of pain during the procedure, fear of a serious
diagnosis, embarrassment, stress while anticipating the results, cost and lack of physician recommendation.
Physicians identified difficulties in scheduling an appointment as one reason women did not use mammography
and both women and physicians identified distance from the screening site, transportation problems and the
absence of symptoms as reasons for non-use.
Conclusion: Women are inhibited from participating in mammography screening in rural Crete. The provision
of more accessible screening services may improve this. However physician recommendation is important in
overcoming women's inhibitions. Primary care physicians serving rural areas need to be aware of barriers
preventing women from attending mammography screening and provide women with information and advice in a sensitive way so women can make informed decisions regarding breast caner screening
Discovery of (R)-2-Amino-6-borono-2-(2-(piperidin-1-yl)ethyl)hexanoic Acid and Congeners As Highly Potent Inhibitors of Human Arginases I and II for Treatment of Myocardial Reperfusion Injury
Recent efforts to identify treatments for myocardial ischemia reperfusion injury have resulted in the discovery of a novel series of highly potent α,α-disubstituted amino acid-based arginase inhibitors. The lead candidate, (R)-2-amino-6-borono-2-(2-(piperidin-1-yl)ethyl)hexanoic acid, compound 9, inhibits human arginases I and II with IC50s of 223 and 509 nM, respectively, and is active in a recombinant cellular assay overexpressing human arginase I (CHO cells). It is 28% orally bioavailable and significantly reduces the infarct size in a rat model of myocardial ischemia/reperfusion injury. Herein, we report the design, synthesis, and structureâactivity relationships (SAR) for this novel series of inhibitors along with pharmacokinetic and in vivo efficacy data for compound 9 and X-ray crystallography data for selected lead compounds cocrystallized with arginases I and II.Fil: Van Zandt, Michael C.. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Whitehouse, Darren L.. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Golebiowski, Adam. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Ji, Min Koo. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Zhang, Mingbao. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Beckett, R. Paul. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Jagdmann, G. Erik. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Ryder, Todd R.. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Sheeler, Ryan. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Andreoli, Monica. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Conway, Bruce. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Mahboubi, Keyvan. Institutes for Pharmaceutical Discovery; Estados UnidosFil: DâAngelo, Gerard. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Mitschler, Andre. UniversitĂ© de Strasbourg; FranciaFil: Cousido Siah, Alexandra. UniversitĂ© de Strasbourg; FranciaFil: Ruiz, Frances X.. UniversitĂ© de Strasbourg; FranciaFil: Howard, Eduardo Ignacio. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de FĂsica de LĂquidos y Sistemas BiolĂłgicos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FĂsica de LĂquidos y Sistemas BiolĂłgicos; Argentina. UniversitĂ© de Strasbourg; FranciaFil: Podjarny, Alberto Daniel. UniversitĂ© de Strasbourg; FranciaFil: Schroeter, Hagen. Mars Incorporated; Estados Unido
Conducting volcanic ash cloud exercises: practising forecast evaluation procedures and the pull-through of scientific advice to the London VAAC
The London Volcanic Ash Advisory Centre (VAAC) provides forecasts on the expected presence of volcanic ash in the atmosphere to mitigate the risk to aviation. It is fundamentally important that operational capability is regularly tested through exercises, to guarantee an effective response to an event. We have developed exercises which practise the pull-through of scientific advice into the London VAAC, the forecast evaluation process, and the decision-making procedures and discussions needed for generating the best possible forecasts under real-time conditions. London VAAC dispersion model forecasts are evaluated against observations. To test this capability in an exercise, we must create observation data for a hypothetical event. We have developed new methodologies for generating and using simulated satellite and lidar retrievals. These simulated observations enable us to practise our ability to interpret, compare, and evaluate model output and observation data under real-time conditions. Forecast evaluation can benefit from an understanding of how different choices of model setup (input parameters), model physics, and driving meteorological data impact the predicted extent and concentration of ash. Through our exercises, we have practised comparing output from model simulations generated using different models, model setups, and meteorological data, supplied by different institutions. Our exercises also practise the communication and interaction between Met Office (UK) scientists supporting the London VAAC and external experts, enabling knowledge exchange and discussions on the interpretation of model output and observations, as we strive to deliver the best response capability for the aviation industry and stakeholders. In this paper, we outline our exercise methodology, including the use of simulated satellite and lidar observations, and the development of the strategy to compare output generated from different modelling systems. We outline the lessons learnt, including the benefits and challenges of conducting exercises which practise our ability to provide scientific advice for an operational response at the London VAAC
Transformations to groundwater sustainability: from individuals and pumps to communities and aquifers
If the success of agricultural intensification continues to rely on the depletion of aquifers and exploitation of (female) labour, transformations to groundwater sustainability will be impossible to achieve. Hence, the development of new groundwater imaginaries, based on alternative ways of organizing society-water relations is highly important. This paper argues that a comparative documentation of grass-roots initiatives to care for, share or recharge aquifers in places with acute resource pressures provides an important source of inspiration. Using a grounded anti-colonial and feminist approach, we combine an ethnographic documentation of groundwater practices with hydrogeological and engineering insights to enunciate, normatively assess and jointly learn from the knowledges, technologies and institutions that characterize such initiatives. Doing this usefully shifts the focus of planned efforts to regulate and govern groundwater away from government efforts to control individual pumping behaviours, to the identification of possibilities to anchor transformations to sustainability in collective action
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