Background Clinicians have difficulty in diagnosing asthma in preschool children with suggestive symptoms. Objective We sought to develop a clinical asthma prediction score for preschool children who ...have asthma-like symptoms for the first time. Methods The Prevalence and Incidence of Asthma and Mite Allergy birth cohort followed 3,963 children for 8 years. Between 0 and 4 years of age, 2,171 (55%) children reported “wheezing,” “coughing at night without a cold,” or both. In these children possible predictor variables for asthma were assessed at the age respiratory symptoms were first reported. Asthma was defined as wheezing, inhaled steroid prescription, or a doctor's diagnosis of asthma at both age 7 and 8 years of age. Results Eleven percent of children with symptoms at 0 to 4 years of age had asthma at 7 to 8 years of age. Eight clinical parameters independently predicted asthma at 7 to 8 years of age: male sex, postterm delivery, parental education and inhaled medication, wheezing frequency, wheeze/dyspnea apart from colds, respiratory infections, and eczema. In 72% of the cases, the model accurately discriminated between asthmatic and nonasthmatic children. A clinical risk score was developed (range, 0-55 points). Symptomatic children with a score of less than 10 points had a 3% risk, whereas children with a score of 30 points or greater had a 42% risk of asthma. Conclusion A risk score based on 8 readily available clinical parameters at the time preschool children first reported asthma-like symptoms predicted the risk of asthma at 7 to 8 years of age.
•Rhyolite lavas do not degas passively, but do so in an explosive manner.•Batched degassing links the chemistry of tephra, bombs, tuffisites, to lava.•Tuffisites bleed off volatiles from magma and ...also permit buffering.•Silicic lavas are the healed remains of explosively fragmented magma.
A long-standing challenge in volcanology is to explain why explosive eruptions of silicic magma give way to lava. A widely cited idea is that the explosive-to-effusive transition manifests a two-stage degassing history whereby lava is the product of non-explosive, open-system gas release following initial explosive, closed-system degassing. Direct observations of rhyolite eruptions indicate that effusive rhyolites are in fact highly explosive, as they erupt simultaneously with violent volcanic blasts and pyroclastic fountains for months from a common vent. This explosive and effusive overlap suggests that pyroclastic processes play a key role in rendering silicic magma sufficiently degassed to generate lava. Here we use precise H-isotope and magmatic H2O measurements and textural evidence to demonstrate that effusion results from explosion(s)—lavas are the direct product of brittle deformation that fosters batched degassing into transient pyroclastic channels (tuffisites) that repetitively and explosively vent from effusing lava. Our measurements show, specifically that D/H ratios and H2O contents of a broad suite of explosive and effusive samples from Chaitén volcano (hydrous bombs, Plinian pyroclasts, tuffisite veins, and lava) define a single and continuous degassing trend that links wet explosive pyroclasts (∼1.6 wt.% H2O, δD=−76.4‰) to dry obsidian lavas (∼0.13 wt.% H2O, δD=−145.7‰). This geochemical pattern is best fit with batched degassing model that comprises small repeated closed-system degassing steps followed by pulses of vapour extraction. This degassing mechanism is made possible by the action of tuffisite veins, which, by tapping already vesicular or brecciated magma, allow batches of exsolved gas to rapidly and explosively escape from relatively isolated closed-system domains and large tracts of conduit magma by giving them long-range connectivity. Even though tuffisite veins render magma degassed and capable of effusing, they are nonetheless the avenues of violent gas and particle transport and thus have the potential to drive explosions when they become blocked or welded shut. Thus the effusion of silicic lava, traditionally thought to be relatively benign process, presents a particularly hazardous form of explosive volcanism.
•Port assessment methodology to determine and compare sustainability goals.•Cross-linking sustainability aims and achievements of a port-city.•Sustainability goals by taking into account port, ...transport, environment and climate.
The challenge for port developments is to minimize long-term uncertainties associated with port operations, risk of increased costs, and large environmental impacts. The aim of this study is to develop a comparative methodology to assess the sustainability performance of a mixed set of ports (different locations, sizes). This methodology involves ranking various long-term port plans and port vision documents against a set of social, economic, and environmental key performance indicators (KPIs) in order to evaluate and interpret future sustainable port-city development plans. The assessment aims to determine the efficiency and sustainability of each of the case study port plans, relative to other ports. Furthermore, the assessment ranks the considered ports based on comparison of pressures within the ecosystems and society, using publically available data in order to evaluate future changes resulting from these pressures. The classification and ranking of each port have been used to gauge the ability of each port to achieve its sustainability goals for port planning as set out in their port plans. The comprehensive results have been compared with the long-term port plan KPIs to evaluate an array of measures both quantitatively and qualitatively. Most of the highest ranking ports have developed a combination of integrated plans, measures, and regulations for sustainable port developments. This indicates that green-port policies need to be interlinked via social, economic, and environmental dimensions utilizing an integrated approach in order to realize maximum potential and strengthen port processes aimed at developing a sustainable port.
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 km
. Deformation and conduit flow models indicate laccolith depths of only ∼20-200 m and overpressures (∼1-10 MPa) that likely stemmed from conduit blockage. Our results show that explosive eruptions may rapidly force significant quantities of magma in the crust to build laccoliths. These iconic intrusions can thus be interpreted as eruptive features that pose unique and previously unrecognized volcanic hazards.
Volcanic eruptions are driven by the growth of gas bubbles in magma. Bubbles grow when dissolved volatile species, principally water, diffuse through the silicate melt and exsolve at the bubble wall. ...On rapid cooling, the melt quenches to glass, preserving the spatial distribution of water concentration around the bubbles (now vesicles), offering a window into pre-eruptive conditions. We measure the water distribution around vesicles in experimentally-vesiculated samples, with high spatial resolution. We find that, contrary to expectation, water concentration increases towards vesicles, indicating that water is resorbed from bubbles during cooling; textural evidence suggests that resorption occurs largely before the melt solidifies. Speciation data indicate that the molecular water distribution records resorption, whilst the hydroxyl distribution records earlier decompressive growth. Our results challenge the emerging paradigm that resorption indicates fluctuating pressure conditions, and lay the foundations for a new tool for reconstructing the eruptive history of natural volcanic products.
•Water resorbs from bubbles into the melt when vesicular magma cools.•Spatial distribution of water around vesicles is preserved in quenched glass.•Distributions of OH and H2Om record pre- and syn-quench conditions respectively.•Potential new tool for reconstructing eruptive history of natural volcanic samples.
Interdisciplinary research often involves analyzing data obtained from different data sources with respect to the same subjects, objects, or experimental units. For example, global positioning ...systems (GPS) data have been coupled with travel diary data, resulting in a better understanding of traveling behavior. The GPS data and the travel diary data are very different in nature, and, to analyze the two types of data jointly, one often uses data integration techniques, such as the regularized simultaneous component analysis (regularized SCA) method. Regularized SCA is an extension of the (sparse) principle component analysis model to the cases where at least two data blocks are jointly analyzed, which - in order to reveal the joint and unique sources of variation - heavily relies on proper selection of the set of variables (i.e., component loadings) in the components. Regularized SCA requires a proper variable selection method to either identify the optimal values for tuning parameters or stably select variables. By means of two simulation studies with various noise and sparseness levels in simulated data, we compare six variable selection methods, which are cross-validation (CV) with the "one-standard-error" rule, repeated double CV (rdCV), BIC, Bolasso with CV, stability selection, and index of sparseness (IS) - a lesser known (compared to the first five methods) but computationally efficient method. Results show that IS is the best-performing variable selection method.
The emplacement mechanisms of rhyolitic lava flows are enigmatic and, despite high lava viscosities and low inferred effusion rates, can result in remarkably, laterally extensive (>30 km) flow ...fields. Here we present the first observations of an active, extensive rhyolitic lava flow field from the 2011-2012 eruption at Cordón Caulle, Chile. We combine high-resolution four-dimensional flow front models, created using automated photo reconstruction techniques, with sequential satellite imagery. Late-stage evolution greatly extended the compound lava flow field, with localized extrusion from stalled, ~35 m-thick flow margins creating >80 breakout lobes. In January 2013, flow front advance continued ~3.6 km from the vent, despite detectable lava supply ceasing 6-8 months earlier. This illustrates how efficient thermal insulation by the lava carapace promotes prolonged within-flow horizontal lava transport, boosting the extent of the flow. The unexpected similarities with compound basaltic lava flow fields point towards a unifying model of lava emplacement.
A challenge in monitoring long‐dormant volcanoes is to discover early signs of reawakening. Mineral springs on Taranaki volcano (2,518 m, New Zealand) have elevated carbonate concentrations, ...δ13CDIC ∼ −5‰ (VPDB) and He isotopes from 5.13 to 5.92 RA, indicating a magmatic volatile source. Stable isotopes demonstrate water recharge occurs near the volcano's summit. Volatile anions and silica are low in a cold (5oC) flank spring at 1,000 m a.s.l., yet elevated in warm springs (25–32oC) associated with travertine deposits at 250–300 m, suggesting a weak hydrothermal component along the flow path. Tritium dating of the cold spring water yields a mean residence time of 7.8 years. This short residence time and magmatic volatile signatures suggest magmatic CO2 persistently flushes Taranaki's upper edifice. Cold spring geochemistry thus reveals volcanic activity at this dormant volcano that otherwise lacks obvious geophysical signs of unrest.
Plain Language Summary
Dormant volcanoes with no obvious signs of activity are difficult to monitor. We show that the earliest released gas from magma, carbon dioxide, emanates from cold springs on the flanks of the dormant Taranaki volcano. The spring water is ∼8 years old when emerging and there were at least 10 eruptions recorded over the last millennium, suggesting that degassing of magma is happening now beneath Taranaki. Increases in the CO2 degassing from these sites could precede an eruption by months to weeks. Warm springs on the outer flanks of the volcano also show signs of being influenced by volcanic processes, providing new sites for potential volcano monitoring.
Key Points
All mineral springs on the flanks of Taranaki volcano (2,518 m) contain magmatic carbon and helium
Tritium dating implies mean residence times of approximately 8 years to the Kōkōwai site, thus elevated carbon suggests present‐day degassing
Warm mineral springs on the lower volcanic flanks at 250–300 m precipitate travertine, and are elevated in SiO2, S, and Cl
In June 2011, an eruption of rhyolite magma began at the Puyehue–Cordón Caulle volcanic complex, southern Chile. By January 2012, explosive activity had declined from sustained pyroclastic (Plinian ...to sub-Plinian) fountaining to mixed gas and ash jetting punctuated by Vulcanian blasts. This explosive activity was accompanied by synchronous effusion of obsidian lava in a hybrid explosive–effusive eruption. Fortuitous climatic conditions permitted ground-based observation and video recording of transient vent dynamics as well as real-time collection of proximal juvenile ash as it sedimented from the active plume. The main eruptive vent complex and site of lava effusion were represented by two loci of Vulcanian blasts within a single tephra cone containing a pancake-shaped proto-lava dome. These blast loci each consisted of clusters of sub-vents that expressed correlated shifts in eruption intensity, indicating the presence of partially connected and/or branching zones of high permeability within the upper conduit. Pyroclast textures were examined by X-ray computed microtomography and their permeability was modelled by lattice Boltzmann simulations. The porosity (39 to 67%) and Darcian permeability (3.1×10−15m2 perpendicular to fabric to 3.8×10−11m2 parallel to fabric) of fine ash emitted during ash jetting indicate that the permeable zones comprised highly sheared, tube-like bubbly magma, and contrast with the low porosity (~17%) and nul permeability of bombs ejected to hundreds of metres from the vent in Vulcanian blasts. Residual H2O content of ash (0.14wt.%) and two bombs (0.2–0.25wt.%), determined by Karl–Fischer titration indicate degassing of this pyroclastic material to near-atmospheric pressures. Ash textures and simple degassing/vesiculation models indicate the onset of permeability by ductile processes of shear-enhanced bubble coalescence in the upper 1 to 1.5km of the conduit. Repeated ash jetting and Vulcanian blasts indicate that such ductile processes were not sufficiently effective to accommodate all degassing requirements, and additional brittle (e.g., fragmentation) events transiently assisted in maintaining an open-system degassing regime that permitted long-lived, hybrid explosive–effusive activity. The eruption at Cordón Caulle has provided an excellent opportunity to closely observe key processes of silicic volcanism.
•Direct observations of a rhyolite eruption•Observation of hybrid explosive–effusive activity•Pyroclast textures in 3-D linked directly to observed eruption dynamics•Both ductile and brittle processes of permeability development drive effusive silicic volcanism.
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