Vertically extensive and unstable magmatic systems Cashman, Katharine V.; Sparks, R. Stephen J.; Blundy, Jonathan D.
Science (American Association for the Advancement of Science),
03/2017, Letnik:
355, Številka:
6331
Journal Article
Recenzirano
Odprti dostop
Volcanoes are an expression of their underlying magmatic systems. Over the past three decades, the classical focus on upper crustal magma chambers has expanded to consider magmatic processes ...throughout the crust. A transcrustal perspective must balance slow (plate tectonic) rates of melt generation and segregation in the lower crust with new evidence for rapid melt accumulation in the upper crust before many volcanic eruptions. Reconciling these observations is engendering active debate about the physical state, spatial distribution, and longevity of melt in the crust. Here we review evidence for transcrustal magmatic systems and highlight physical processes that might affect the growth and stability of melt-rich layers, focusing particularly on conditions that cause them to destabilize, ascend, and accumulate in voluminous but ephemeral shallow magma chambers.
Electromagnetic metasurface cloaks provide an alternative paradigm toward rendering arbitrarily shaped scatterers invisible. Most transformation-optics (TO) cloaks intrinsically need wavelength-scale ...volume/thickness, such that the incoming waves could have enough long paths to interact with structured meta-atoms in the cloak region and consequently restore the wavefront. Other challenges of TO cloaks include the polarization-dependent operation to avoid singular parameters of composite cloaking materials and limitations of canonical geometries, e.g., circular, elliptical, trapezoidal, and triangular shapes. Here, we report for the first time a conformal-skin metasurface carpet cloak, enabling to work under arbitrary states of polarization (SOP) at Poincaré sphere for the incident light and arbitrary conformal platform of the object to be cloaked. By exploiting the foundry three-dimensional (3D) printing techniques to fabricate judiciously designed meta-atoms on the external surface of a conformal object, the spatial distributions of intensity and polarization of its scattered lights can be reconstructed exactly the same as if the scattering wavefront were deflected from a flat ground at any SOP, concealing targets under polarization-scanning detections. Two conformal-skin carpet cloaks working for partial- and full-azimuth plane operation are respectively fabricated on trapezoid and pyramid platforms via 3D printing. Experimental results are in good agreement with numerical simulations and both demonstrate the polarization-insensitive cloaking within a desirable bandwidth. Our approach paves a deterministic and robust step forward to the realization of interfacial, free-form, and full-polarization cloaking for a realistic arbitrary-shape target in real-world applications.
Environmental pollution by heavy metals resulting from rapid economic development is a major concern. Soil, water, wheat, and rice samples were collected from the Lihe River Watershed in the Taihu ...Region (east China). In this study area, many types of industrial plants, including ceramics factories, plants working with refractory materials, and chemical plants are densely distributed and cause serious heavy metal pollution. In addition, well-developed transportation and agricultural activities are also important sources of heavy metals. Thus, the concentrations of selected heavy metals including cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) in the samples were analyzed to evaluate their potential integral risk (IR) to the health of the local population. Accordingly, the spatial distribution pattern of the IR values was determined in the study. The soil in the study area showed heavy Cd pollution, whereas the pollution by other elements was relatively slight. When the proportions of grain samples in which the concentrations exceeded the tolerance limits were examined, the grains were primarily contaminated with Pb, Ni, Cd, and Zn; and less contaminated with Cu and Cr. The drinking water of the local inhabitants was safe. The average IR value was 3.53 for adults and 3.91 for children, indicating that both adults and children may experience adverse health effects. The spatial distribution pattern of the IR values among the exposed populations in the study area showed high values in the eastern and middle parts, with maximum values >5, and low values in the western part, with minimum values <2. This is consistent with the distributions of the industries and the population. The study may provide a basis for comparison to other regions both in China and worldwide.
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•Elevated concentrations of heavy metals were observed in the soil and crop locally.•Risk assessment of heavy metal contamination was significant for local inhabitants.•IR via ingesting rice, wheat, water and soil was high, especially for children.•Consumption of rice and wheat was the major contribution to risk.•The spatial distribution pattern of IR was predicted using geostatistical analysis.
Microplastic pollution within the marine environment is of pressing concern globally. Accordingly, spatial monitoring of microplastic concentrations, composition and size distribution may help to ...identify sources and entry pathways, and hence allow initiating focused mitigation. Spatial distribution patterns of microplastics were investigated in two compartments of the southern North Sea by collecting sublittoral sediment and surface water samples from 24 stations. Large microplastics (500−5000 μm) were detected visually and identified using attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopy. The remaining sample was digested enzymatically, concentrated onto filters and analyzed for small microplastics (11−500 μm) using Focal Plane Array (FPA) FTIR imaging. Microplastics were detected in all samples with concentrations ranging between 2.8 and 1188.8 particles kg−1 for sediments and 0.1–245.4 particles m−3 for surface waters. On average 98% of microplastics were <100 μm in sediments and 86% in surface waters. The most prevalent polymer types in both compartments were polypropylene, acrylates/polyurethane/varnish, and polyamide. However, polymer composition differed significantly between sediment and surface water samples as well as between the Frisian Islands and the English Channel sites. These results show that microplastics are not evenly distributed, in neither location nor size, which is illuminating regarding the development of monitoring protocols.
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•All 46 analyzed sediment and surface water samples contained microplastics.•Microplastic concentrations were higher in sediment than surface water samples.•Polymer composition differed significantly between surface waters and sediments.•Microplastics <500 μm were more abundant and divers in polymer type than large ones.•Particles smaller 100 μm dominated clearly in both environmental compartments.
Capsule: Microplastic concentrations and compositions differ significantly between environmental compartments. Geographic distribution patterns are revealed by a statistical approach. Microplastics <500 μm are more abundant and diverse than >500 μm ones, rendering the exclusive analysis of later ones insufficient for environmental risk assessment.
Resumo O uso de agrotóxicos na agricultura brasileira é um problema de saúde pública, dadas as contaminações no ambiente, em alimentos e as intoxicações na saúde humana. Objetivou-se apresentar a ...distribuição espacial da área plantada de lavouras, consumo de agrotóxicos e agravos à saúde relacionados, como estratégia de Vigilância em Saúde. Obteve-se dados de área plantada de 21 culturas predominantes, indicadores de consumo de agrotóxicos por hectare para cada cultura e agravos à saúde. Espacializou-se o consumo de agrotóxicos nos municípios brasileiros e correlacionou-se às incidências de intoxicações por agrotóxicos: aguda, subaguda e crônica. Constatou-se predomínio dos cultivos de soja, milho e cana, que juntos corresponderam a 76% da área plantada no Brasil em 2015. Pulverizou-se 899 milhões de litros de agrotóxicos nessas lavouras, com Mato Grosso, Paraná e Rio Grande Sul tendo utilizado as maiores quantidades. Os agravos à saúde apresentaram correlações positivas e significativas com o uso de agrotóxicos. A estratégia metodológica possibilitou identificar municípios prioritários para a Vigilância em Saúde e o desenvolvimento de ações intersetoriais de prevenção e mitigação dos impactos dos agrotóxicos na saúde e ambiente.
In order to obtain the large scale spatial distribution of surface visibility, a novel technique is developed to convert satellite-retrieved aerosol optical depth (AOD) to surface visibility through ...aerosol scale height. Specifically, the aerosol scale height is calculated using the advanced optimal interpolation (OI) method by assimilating CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) measurements into GEOS-Chem stimulation results. The assimilated analysis field is then combined with MODIS AOD to calculate surface visibility. Validation against ground observation in China shows that best monthly correlation between collocated satellite-retrieved visibility and surface visibility data is above 0.5. Reasonable agreement is also found in seasonal and spatial variability.
Abstract
Geothermal resources are a kind of ecological energy with great market potential. In order to promote the development and utilization of geothermal resources in Dunhua area and promote ...economic and social development, the advanced WFEM is used to delineate the hidden fault zone and fracture zone, determine the basement depth and the spatial distribution of hidden faults, find out the geological conditions of geothermal resources in this area, and make a preliminary evaluation of geothermal resources, analyze the exploitation potential of geothermal resources.
Microplastics (<5 mm) are considered to be emerging pollutants of global concern. Investigations on microplastics pollution in coastal and marine environments have increased recently but knowledge ...gaps still exist regarding microplastics in coastal beach soils with high-intensity human activities. In the present study a total of 120 soil samples were taken from 53 sites along >3000 km of coastline in Shandong province, east China, adjacent to both the Bohai Sea and the Yellow Sea coastlines under different land use management. Microplastics were separated from the soil samples using a continuous flow and floating separation apparatus. The shape type, size, abundance, spatial distribution, polymer composition and surface morphology of the microplastics were identified by a range of advanced microscopic and micro-analytical methods. The analytical results show that seven shape types, namely foams, pellets, fragments, flakes, fibers, films and sponges, were present in the beach soils. The polymer composition of the microplastics included polyethylene, polypropylene, polystyrene, polyether urethane and a polymer blend of both polyethylene and polypropylene. Approximately 60% of the observed microplastics had a size range < 1 mm. Microplastic abundance varied greatly among the soils, ranging from 1.3 to 14,712.5 N kg−1 (dry weight) as influenced by high-intensity human activities such as mariculture, tourism, and port construction. The seven shape types of microplastics from the coastal environment had different weathering surface morphologies, showing scratches, creases, micropores, cracks, either concave or convex, and of various shapes and sizes, possibly due to physical friction, photochemical oxidation and/or animal attack. Algae or crude oil was observed on the surface of some microplastics. The weathered surfaces of microplastics might act as a high-capacity carrier with adhering microorganisms and chemicals. Further studies are required on the weathering processes, sorption capacity and transport of microplastics especially in smaller size (<1 mm) under coastal conditions.
•Comprehensive study on microplastics in coastal soils as influenced by human activities.•Different beaches showed different levels of microplastic contamination.•Flakes and white foams dominated the microplastics in the study area.•Surface morphology of microplastics showed deep weathering in the beaches.
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