76 research outputs found
Multiple melt bodies fed the AD 2011 eruption of Puyehue-Cordon Caulle, Chile
ArtÃculo de publicación ISIWithin the volcanological community there is a growing awareness that many large-to smallscale, point-source eruptive events can be fed by multiple melt bodies rather than from a single magma reservoir. In this study, glass shard major-and trace-element compositions were determined from tephra systematically sampled from the outset of the Puyehue-Corden Caulle (PCC) eruption (similar to 1 km(3)) in southern Chile which commenced on June 4th, 2011. Three distinct but cogenetic magma bodies were simultaneously tapped during the paroxysmal phase of this eruption. These are readily identified by clear compositional gaps in CaO, and by Sr/Zr and Sr/Y ratios, resulting from dominantly plagioclase extraction at slightly different pressures, with incompatible elements controlled by zircon crystallisation. Our results clearly demonstrate the utility of glass shard major-and trace-element data in defining the contribution of multiple magma bodies to an explosive eruption. The complex spatial association of the PCC fissure zone with the Liquine-Ofqui Fault zone was likely an influential factor that impeded the ascent of the parent magma and allowed the formation of discrete melt bodies within the sub-volcanic system that continued to independently fractionate.Argentine PIP CONICET
2011 0311
FONCYT PICT
2010 2046
Iniciativa Cientifica Milenio grants
P02-51
NC120066
Chilean Fondecyt
115146
Secondary lahar hazard assessment for Villa la Angostura, Argentina, using Two-Phase-Titan modelling code during 2011 Cordón Caulle eruption
This paper presents the results of lahar modelling in the town of Villa La Angostura (Neuquén-Argentina) based on the Two-Phase-Titan modelling computer code. The purpose of this exercise is to provide decision makers with a useful tool to assess lahar hazard during the 2011 PuyehueCordón Caulle Volcanic Complex eruption. The possible occurrence of lahars mobilized from recent ash falls that could reach the city was analysed. The performance of the TwoPhase-Titan model using 15 m resolution digital elevation models (DEMs) developed from optical satellite images and from radar satellite images was evaluated. The output of these modellings showed inconsistencies that, based on field observations, were attributed to bad adjustment of the DEMs to real topography. Further testing of results using more accurate radar-based 10 m DEM, provided more realistic predictions. This procedure allowed us to simulate the path of flows from Florencia, Las Piedritas and Colorado creeks, which are the most hazardous streams for debris flows in Villa La Angostura. The output of the modelling is a valuable tool for city planning and risk management especially considering the glacial geomorphic features of the region, the strong urban development growth and the land occupation that has occurred in the last decade in Villa La Angostura and its surroundings.Fil: Córdoba, G.. Universidad de Nariño; ColombiaFil: Villarosa, Gustavo. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones En Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Reg.universidad Bariloche. Instituto de Investigaciones En Biodiversidad y Medioambiente; ArgentinaFil: Sheridan, M.. State University of New York at Buffalo; Estados UnidosFil: Viramonte, Jose German. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energia No Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de FÃsica. Instituto de Investigaciones en Energia No Convencional; ArgentinaFil: Beigt, Debora. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones En Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Reg.universidad Bariloche. Instituto de Investigaciones En Biodiversidad y Medioambiente; ArgentinaFil: Salinas de Salmuni, Nelida Graciela. Comision Nacional de Actividades Espaciales; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentin
Comparison of Synthetic Pathways for Obtaining Fluorescent Nanomaterials Based on Halloysite and Carbon Dots for Potential Biological Sensing
Recently, fluorescent sensors have gained considerable attention due to their high sensitivity, low cost and noninvasiveness. Among the different materials that can be used for this purpose, carbon dots (CDs) represent valuable candidates for applications in sensing. These, indeed, are easily synthesized, show high quantum yield and are highly biocompatible. However, it was pointed out that the photoluminescence properties of these nanomaterials are strictly dependent on the synthetic and purification methods adopted. The presence of halloysite nanotubes (HNTs), a natural, low cost and biocompatible clay mineral, has been found to be efficient in obtaining small and highly monodispersed CDs without long and tedious purification techniques. Herein, we report the comparison of synthetic pathways for obtaining halloysite-N-doped CDs (HNTs-NCDs) that could be used in biological sensing. One was based on the synthesis of N-doped CDs by a bottom-up approach on HNTs' surface by a MW pyrolysis process; the other one was based on the post-modification of pristine N-doped CDs with halloysite derivatives. The evaluation of the best synthetic route was performed by different physico-chemical techniques. It was found that the bottom-up approach led to the formation of N-doped CDs with different functional groups onto the HNTs' surface. This evidence was also translated in the different fluorescence quantum yields and the existence of several functional groups in the obtained materials was investigated by potentiometric titrations. Furthermore, the ability of the synthesized nanomaterials as sensors for Fe3+ ions detection was assessed by spectroscopic measurements, and the cellular uptake was verified by confocal/fluorescence microscopies as well
Secondary lahar hazard assessment for Villa la Angostura, Argentina, using Two-Phase-Titan modelling code during 2011 Cordón Caulle eruption
This paper shows the results of secondary lahar modelling in Villa La Angostura town (Neuquén-Argentina) based on the Two-Phase-Titan modelling computer code, which aimed to provide decision makers a useful tool to assess lahar hazard during the 2011 Puyehue-Cordón Caulle Volcanic Complex eruption. Possible occurrence of secondary lahars that could reach the city was analized. The performance of the Two-Phase-Titan model using 15 m resolution DEMs developed from optical satellite images and from radar satellite images was evaluated. The output of these modellings showed inconsis- tencies that, based on field observations, were attributed to bad adjustment of DEMs to real topography. Further testing of results using more accurate radar based 10 m DEM, proved more realistic predictions. The procedure allowed to simulate the path of flows from Florencia, Las Piedritas and Colorado creeks, which are the most influenc-
ing streams in Villa La Angostura. The output of the modelling is a valuable tool for city planning and risk management especially considering the glacial geomorphology
features of the region, the strong urban development growth and the land occupation tendencies observed in last decade in Villa La Angostura and its surroundings
An 18,000 year-long eruptive record from Volcán Chaitén, northwestern Patagonia:Paleoenvironmental and hazard-assessment implications
The 2008 eruption of Volcán Chaitén (VCha) in northwestern Patagonia was the first explosive rhyolitic eruption to have occurred within a century and provided an unprecedented scientific opportunity to examine all facets of the eruption ranging from magma rheology/ascent rates to ash-fall effects on biota and infrastructure. Up to very recently it was thought that the latest eruption prior to the 2008 event occurred c. 9750 cal. a BP. Although a number of researchers have recognised additional eruptive products, but their stratigraphy, age, and geochemical attributes have not been systematically described and/or recorded. In this study, we provide a detailed examination of andic cover-beds and tephra-bearing lake sequences located both proximally and distally to VCha, which record a series of hitherto unknown rhyolitic eruptive products and place all previous observations firmly within a coherent stratigraphic framework. Through major- and trace-element glass shard geochemistry we are able to confidently verify eruptive source. A total of 20 discrete tephra beds are recognised, with at least 10 having widespread areal distributions and/or depositional imprints broadly comparable to, or greater than, the 2008-tephra event. This record indicates that VCha has been continuously but intermittently active as far back as the end of the Last Glacial Maximum (c. 18,000 cal a BP) with two dominant, genetically related magma types and an intermediary ¿mixed¿ type. Before this the eruptive record has been largely obscured and/or erased by widespread Andean piedmont glaciation. However, based on the tempo of VCha activity over the last c. 18,000 years, older VCha eruptives can be anticipated to occur as well as future hazardous explosive events. The new eruptive inventory will ultimately be useful for correlating equivalent-aged sequences and refining long-term eruptive tempo as well as corresponding temporal changes in magmatic evolution
Long-term effectiveness of the midwifery initiated oral health-dental service program on maternal oral health knowledge, preventative dental behaviours and the oral health status of children in Australia
Background
The Midwifery Initiated Oral Health-Dental Service was developed to train midwives to promote maternal oral health, and a large trial showed it substantially improved the oral health, knowledge and behaviours of pregnant women.
Aim
Evaluate the long-term effectiveness of the program (post-trial) on maternal oral health knowledge, dental behaviours, and early childhood caries in offspring.
Methods
A prospective cohort study involving 204 women and children 3–4 years (followed after trial) was conducted in Sydney, Australia from 2017 to 2019.
Results
The program did not have a significant impact on the study measures. Mothers who received the program did have comparatively better knowledge around preventative behaviours to reduce early childhood caries and significantly more mothers were engaging in a key behaviour of using a cup to feed their child. Overall maternal oral health knowledge and level of education did have a protective effect on the dental decay of children. Higher knowledge and levels of education reduced the odds of having a dmft of one or more by over half (OR 0.473), and almost 80% (OR 0.212) respectively.
Conclusions
Although the MIOH-DS program was not effective, there is still value in exploring other complementary interventions to improve maternal oral health, especially for disadvantaged families. Future research should focus on co-designing an antenatal and postnatal oral health intervention and exploring its long-term impact on the oral health of children
Carrier capability of halloysite nanotubes for the intracellular delivery of antisense PNA targeting mRNA of neuroglobin gene
Peptide nucleic acid (PNA) is a DNA mimic that shows good stability against nucleases and proteases, forming strongly recognized complementary strands of DNA and RNA. However, due to its feeble ability to cross the cellular membrane, PNA activity and its targeting gene action is limited. Halloysite nanotubes (HNTs) are a natural and low-cost aluminosilicate clay. Because of their peculiar ability to cross cellular membrane, HNTs represent a valuable candidate for delivering genetic materials into cells. Herein, two differently charged 12-mer PNAs capable of recognizing as molecular target a 12-mer DNA molecule mimicking a purine-rich tract of neuroglobin were synthetized and loaded onto HNTs by electrostatic attraction interactions. After characterization, the kinetic release was also assessed in media mimicking physiological conditions. Resonance light scattering measurements assessed their ability to bind complementary single-stranded DNA. Furthermore, their intracellular delivery was assessed by confocal laser scanning microscopy on living MCF-7 cells incubated with fluorescence isothiocyanate (FITC)-PNA and HNTs labeled with a probe. The nanomaterials were found to cross cellular membrane and cell nuclei efficiently. Finally, it is worth mentioning that the HNTs/PNA can reduce the level of neuroglobin gene expression, as shown by reverse transcription-quantitative polymerase chain reaction and western blotting analysis
Mapping socio-environmental vulnerability and environmental health promotion in a rural community of Lamarão, Federal District, Brazil, 2011
Objetivo: realizar atividade de ensino e extensão com alunos de graduação para construção de diagnóstico participativo sobre as condições de vida, ambiente e trabalho em núcleo populacional rural, visando subsidiar ações de promoção da saúde pela equipe de agentes comunitários da Estratégia Saúde da FamÃlia. Métodos: trabalho realizado no Núcleo Rural do Lamarão, no Distrito Federal, de outubro/2010 a janeiro/2011. Alunos, conjuntamente com agentes comunitários de saúde, por meio de entrevistas, visitas e oficinas, aplicaram instrumentos de Estimativa Participativa Rápida e de construção de mapa de vulnerabilidade socioambiental e de contextos de promoção da saúde ambiental. Resultados: identificaram-se como promotores da vida na comunidade: diversidade de produção de alimentos, liberdade e segurança, união e organização da comunidade, geração de empregos e natureza. Foram considerados ameaçadores à vida: cultura alimentar, uso inadequado de agrotóxicos, uso incorreto de equipamentos de proteção individual, pulverização aérea, falta de lazer, falta de transporte, uso de drogas lÃcitas e ilÃcitas. Conclusão: a partir do diagnóstico, será construÃdo um projeto de intervenção participativo que incorporará caracterÃsticas de ensino, pesquisa e extensão na relação Saúde, Trabalho, Ambiente e Nutrição.Objective: To involve undergraduate students in an extension activity aimed at conducting a participatory diagnosis on life, environment, and work conditions in a rural settlement, with the purpose of raising goals for future health promotion actions performed by community health agents of the Family Health Strategy. Methods: The study was held between October 2010 and January 2011 in the rural community of Lamarão, located in the Federal District in Brazil. By means of interviews, visits, and workshops, students and community health agentes used Participatory Rapid Appraisal instruments as well as tools for mapping socio-environmental vulnerability and health promotion related issues. Results: The following were identified as life promotion factors in the community: food production diversity, freedom and safety, unity and community organization, job generation, and nature. Considered as threatening to life were: food culture, improper use of pesticides, inadequate use of personal protective equipment, aerial spraying, lack of leisure, lack of transportation, use of licit and illicit drugs. Conclusion: A participatory intervention project will be developed, which will incorporate teaching, research and extension activities regarding Health, Work, Environment, and Nutrition
What do antenatal care providers understand and do about oral health care during pregnancy: a cross-sectional survey in New South Wales, Australia
BACKGROUND: There is mounting evidence to support the lack of awareness among pregnant women about health consequences and long term risks associated with poor oral hygiene during pregnancy. A recognised and important point of influence is their interaction with health professionals, particularly when receiving Antenatal Care. However, there is limited evidence about the perceptions of ANC providers in Australia toward the provision of perinatal oral healthcare. This study was undertaken to explore the knowledge, attitudes and practices of Antenatal Care (ANC) providers in New South Wales (NSW), Australia providing perinatal oral healthcare and to identify barriers to and predictors of their practices in this area. METHODS: A cross sectional survey was undertaken of ANC providers (general practitioners, obstetricians/gynaecologists and midwives) practising in NSW, Australia. Participants were recruited through their professional organisations via email, postal mail, and networking at conferences. The survey addressed the domains of knowledge, attitude, barriers and practices towards oral healthcare, along with demographics. Data was entered into SPSS software and analysed using descriptive and inferential statistics. RESULTS: A total of 393 surveys (17.6% response rate) were completed comprising 124 general practitioners, 74 obstetricians/gynaecologists and 195 midwives. The results showed limited knowledge among ANC providers regarding the impact of poor maternal oral health on pregnancy/infant outcomes. Most (99%) participants agreed that maternal oral health was important yet few were discussing the importance of oral health or advising women to visit a dentist (16.4–21.5%). Further, less than a third felt they had the skills to provide oral health advice during pregnancy. ANC providers who were more knowledgeable about maternal oral health, had training and information in this area and greater experience, were more likely to engage in practices addressing the oral health of pregnant women. CONCLUSION: The findings suggest that ANC providers in NSW are not focussing on oral health with pregnant women. ANC providers seem willing to discuss oral health if they have appropriate education/training and information in this area. Further research at a national level is required to confirm whether these findings are similar in all Australian states
Probabilistic lahar hazard assesment by modeling: the case of Villa La Angostura, provincia de Neuquén, Argentina
En este trabajo se propone una manera de estimar la amenaza probabilÃstica por lahares. Se aplican métodos estadÃsticos para obtener un muestreo representativo de todas las posibles combinaciones que resultan en decenas de escenarios hipotéticos, a partir de los cuales se obtiene la probabilidad de impacto de un evento potencialmente destructivo con determinada caracterÃstica. A fin de determinar esta probabilidad, se usa una aproximación Bayesiana, que permite tener en cuenta la posibilidad de que los lugares de interés sean afectados desde varias fuentes. Los escenarios hipotéticos se simulan computacionalmente con el programa Titan2F. La metodologÃa se aplica a la población Villa la Angostura, provincia de Neuquén, Argentina.Le but de ce travail est d'évaluer l?aléa lahar de manière probabiliste. Des méthodes statistiques visent à obtenirun échantillonnage représentatif de toutes les combinaisons posibles qui délivrent des dizaines de scénarios hypothétiques,à partir desquels on obtient la probabilité d'impacts d'un événement potentiellement destructif. Une aproche bayésienne estutilisée pour déterminer cette probabilité qui permet de tenir compte du fait que la zone d'intérêt soit affectée de diversesmanières. La modélisation numérique des scénarios hypothétiques utilise le code Titan2F et s'applique à la ville Villa la Angostura, province de Neuquen, en Argentine.Fil: Córdoba, G.. Universidad de Nariño; ColombiaFil: Villarosa, Gustavo. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Patagonia Norte. Instituto Andino Patagónico de TecnologÃas Biológicas y Geoambientales. Universidad Nacional del Comahue. Instituto Andino Patagónico de TecnologÃas Biológicas y Geoambientales; ArgentinaFil: Guerrero, A.. Universidad de Nariño; Colombi
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