Mineralogical analyses and in vitro screening tests for the rapid evaluation of the health hazard of volcanic ash at Rabaul volcano, Papua New Guinea   总被引：1，自引：1，他引：0  

Jennifer S. Le Blond  Claire J. Horwell  Peter J. Baxter  Sabina A. K. Michnowicz  Maura Tomatis  Bice Fubini  Pierre Delmelle  Christina Dunster  Herman Patia 《Bulletin of Volcanology》2010,72(9):1077-1092

The continuous ash and gas emissions from the Tavurvur cone in Rabaul caldera, Papua New Guinea, during 2007–08, raised concerns regarding how exposure would affect the respiratory health of nearby populations and impact on the environment. As part of a formal evaluation of the effects of volcanic emissions on public health, we investigated the potential health hazard of the ash using a suite of selected mineralogical analyses and in vitro toxicity screening tests. The trachy-andesitic ash comprised 2.1–6.7 vol.% respirable (sub-4 μm diameter) particles. The crystalline silica content was 1.9–5.0 wt.% cristobalite (in the bulk sample) with trace amounts of quartz and/or tridymite. Scanning electron microscopy showed that the ash particles were angular with sparse, fibre-like particles (∼3–60 μm max. diameter) observed in some samples, which we confirmed to be CaSO₄ (gypsum, at <6 wt.% in the bulk samples) and not asbestiform fibres. The ash specific surface area was low (0.1–2.7 m² g⁻¹). The leached solution from one of the ash samples was slightly acidic (pH 5.6), but did not contain high levels of toxic metals (such as F, Cu, Zn, Mn, As, Ni and Cd) when compared to previously tested volcanic ash leachates. Ash samples generated potentially-harmful hydroxyl radicals through an iron-mediated catalytic reaction, in the range of 0.15–2.47 μmol m⁻² (after 30 min of reaction). However, measurement of particle oxidative capacity (potential oxidative stress reaction using ascorbic acid) and silica-like injury to red blood cells (erythrolysis assay, i.e. measurement of cell death) nevertheless revealed low biological reactivity. The findings suggest that acute exposure to the ash would have a limited potential to exacerbate pre-existing conditions such as asthma or chronic bronchitis, and the potential for chronic exposure leading to silicosis was low.  相似文献   

Origin of siderite mineralisation in Petrova and Trgovska Gora Mts., NW Dinarides     

Sibila Borojević Šoštarić  Ladislav A. Palinkaš  Sabina Strmić Palinkaš  Vladimir Bermanec  Franz Neubauer  Jorge Spangenberg  Walter Prochaska 《Mineralogy and Petrology》2009,97(1-2):111-128

The Petrova and Trgovska Gora Mts. (Gora=Mountain) are Variscan basement units incorporated into the northwestern Dinarides during the Alpine orogeny. They host numerous siderite-quartz-polysulphide, siderite-chalcopyrite, siderite-galena and barite veins, as well as stratabound hydrothermal-replacement ankerite bodies within carbonates in non-metamorphosed, flysch-like Permo-Carboniferous sequences. The deposits have been mined for Cu, Pb, Ag and Fe ores since Medieval times. Fluid inclusion studies of quartz from siderite-polysulphide-quartz and barite veins of both regions have shown the presence of primary aqueous NaCl?CaCl₂±MgCl₂?H₂O±CO₂ inclusions. The quartz-sulphide stage of both regions show variable salinities; 2.7–26.2 wt% NaCl eq. for the Trgovska Gora region and 3.4–23.4 wt% NaCl eq. for the Petrova gora region, and similar homogenisation temperatures (100–230°C). Finally, barite is precipitated from low salinity-low temperature solutions (3.7–15.8 wt % NaCl equ. and 115–145°C). P-t conditions estimated via isochore construction yield formation temperatures between 180–250°C for the quartz-sulphide stage and 160–180°C for the barite stage, using a maximum lithostatic pressure of 1 kbar (cc. 3 km of overburden). The sulphur isotope composition of barite from both deposits indicates the involvement of Permian seawater in ore fluids. This is supported by the elevated bromium content of the fluid inclusion leachates (120–660 ppm in quartz, 420–960 ppm in barite) with respect to the seawater, indicating evaporated seawater as the major portion of the ore-forming fluids. Variable sulphur isotope compositions of galena, pyrite and chalcopyrite, between ?3.2 and +2.7‰, are interpreted as a product of incomplete thermal reduction of the Permian marine sulphate mixed with organically- and pyrite-bound sulphur from the host sedimentary rocks. Ore-forming fluids are interpreted as deep-circulating fluids derived primarily from evaporated Permian seawater and later modified by interaction with the Variscan basement rocks. ⁴⁰Ar/³⁹Ar data of the detrital mica from the host rocks yielded the Variscan age overprinted by an Early Permian tectonothermal event dated at 266–274 Ma. These ages are interpreted as those reflecting hydrothermal activity correlated with an incipient intracontinental rifting in the Tethyan domain. Nevertheless, 75 Ma recorded at a fine-grained sericite sample from the alteration zone is interpreted as a result of later resetting of white mica during Campanian opening/closure of the Sava back arc in the neighbouring Sava suture zone (Ustaszewski et al. 2008).  相似文献   

Expected changes in agroclimatic conditions in Central Europe     

Miroslav Trnka  Josef Eitzinger  Daniela Semer��dov��  Petr Hlavinka  Jan Balek  Martin Dubrovsky  Gerhard Kubu  Petr ?t��p��nek  Sabina Thaler  Martin Mo?ny  Zden��k ?alud 《Climatic change》2011,108(1-2):261-289

During the past few decades, the basic assumption of agroclimatic zoning, i.e., that agroclimatic conditions remain relatively stable, has been shattered by ongoing climate change. The first aim of this study was to develop a tool that would allow for effective analysis of various agroclimatic indicators and their dynamics under climate change conditions for a particular region. The results of this effort were summarized in the AgriClim software package, which provides users with a wide range of parameters essential for the evaluation of climate-related stress factors in agricultural crop production. The software was then tested over an area of 114,000 km² in Central Europe. We have found that by 2020, the combination of increased air temperature and changes in the amount and distribution of precipitation will lead to a prolonged growing season and significant shifts in the agroclimatic zones in Central Europe; in particular, the areas that are currently most productive will be reduced and replaced by warmer but drier conditions in the same time the higher elevations will most likely experience improvement in their agroclimatic conditions. This positive effect might be short-lived, as by 2050, even these areas might experience much drier conditions than observed currently. Both the rate and the scale of the shift are amazing as by 2020 (assuming upper range of the climate change projections) only 20?C38% of agriculture land in the evaluated region will remain in the same agroclimatic and by 2050 it might be less than 2%. On the other hand farmers will be able to take advantage of an earlier start to the growing season, at least in the lowland areas, as the proportion of days suitable for sowing increases. As all of these changes might occur within less than four decades, these issues could pose serious adaptation challenges for farmers and governmental policies. The presented results also suggest that the rate of change might be so rapid that the concept of static agroclimatic zoning itself might lose relevance due to perpetual change.  相似文献   

Characteristics of Rhodamine WT and Fluorescein as Adsorbing Ground-Water Tracers   总被引：5，自引：0，他引：5  

David A. Sabatini  T. AI Austin 《Ground water》1991,29(3):341-349

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Solubilization and Microemulsification of Chlorinated Solvents Using Direct Food Additive (Edible) Surfactants   总被引：8，自引：0，他引：8  

Bor-Jier Shiau  David A. Sabatini  Jeffrey H. Harwell 《Ground water》1994,32(4):561-569

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Large-scale modes impact on Iraq climate variability     

Jasim?Al-KhalidiEmail author  Mihai?Dima  Sabina?Stefan 《Theoretical and Applied Climatology》2018,133(1-2):179-190

The impact of large-scale modes on Iraq climate is investigated here based on winter and spring fields of temperature and precipitation. The temperature data (1971–2010) was recorded at 8 stations whereas the precipitation fields (1981–2010) were recorded at 18 locations. Empirical orthogonal function analyses were performed in order to characterize the spatial variability of the Iraq climatological parameters. The relationships between the global sea surface temperature, sea level pressure, and geopotential height fields with the dominant modes of Iraq temperature and precipitation were also investigated. Correlation and regression maps emphasize links between Iraq climate and large-scale modes, like the Atlantic Multidecadal Oscillation and the El Niño Southern Oscillation phenomenon.  相似文献   

Distribution of ostracods in west-central Argentina related to host-water chemistry and climate: implications for paleolimnology     

D. Sabina D’Ambrosio  Adriana García  Analía R. Díaz  Allan R. Chivas  María C. Claps 《Journal of Paleolimnology》2017,58(2):101-117

Ecological and biogeographical studies of Neotropical non-marine ostracods are rare, although such information is needed to develop reliable paleoecological and paleoclimatic reconstructions for the region. An extensive, yet little explored South American area of paleoclimatic interest, is the arid-semiarid ecotone (Arid Diagonal) that separates arid Patagonia from subtropical/tropical northern South America, and lies at the intersection of the Pacific and Atlantic atmospheric circulation systems. This study focused on the Laguna Llancanelo basin, Argentina, a Ramsar site located within the Arid Diagonal, and was designed to build a modern dataset using ostracods (diversity, spatial distribution, seasonality, habitat preferences) and water chemistry. Cluster and multivariate analysis of the data indicated that salinity is the most significant variable segregating two ostracod groups. Limnocythere aff. staplini is the only species that develops abundant populations in the saline ephemeral Laguna Llancanelo during almost all seasons, and is accompanied by scarce Cypridopsis vidua in summer. The latter species is abundant in freshwater lotic sites, where Ilyocypris ramirezi, Herpetocypris helenae, and Cyprididae indet. are also found in large numbers. Darwinula stevensoni, Penthesilenula incae, Heterocypris incongruens, Chlamydotheca arcuata, Chlamydotheca sp., Herpetocypris helenae, and Potamocypris smaragdina prefer freshwater lentic conditions (springs), with C. arcuata and Chlamydotheca sp. found only in the Carapacho warm spring, which has a year-round constant temperature of ~20 °C. Seasonal sampling was necessary because some taxa display a highly seasonal distribution. Species that were recorded have either subtropical or Patagonian affinities, although a few taxa are endemic or common to both regions. These data can serve as modern analogues for reconstructing the late Quaternary history of the area, and to investigate the extent and position of the arid/semiarid ecotone (Arid Diagonal) during past glacial/interglacial cycles.  相似文献   

A search for low surface brightness dwarf galaxies in different environments     

Sarah Roberts  Jonathan Davies  Sabina Sabatini  Wim van Driel  Karen O'Neil  Maarten Baes  Suzanne Linder  Rodney Smith  Rhodri Evans 《Monthly notices of the Royal Astronomical Society》2004,352(2):478-492

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On the feasibility of studying the exospheres of Earth-like exoplanets by Lyman-<Emphasis Type="Italic">α</Emphasis> monitoring     

Ana I. Gómez de Castro  Leire Beitia-Antero  Sabina Ustamujic 《Experimental Astronomy》2018,45(2):147-163

Observations of the Earth’s exosphere have unveiled an extended envelope of hydrogen reaching further than 10 Earth radii composed of atoms orbiting around the Earth. This large envelope increases significantly the opacity of the Earth to Lyman α (Lyα) photons coming from the Sun, to the point of making feasible the detection of the Earth’s transit signature from 1.35 pc if pointing with an 8 meter primary mirror space telescope through a clean line of sight (N _H <?10¹⁷ cm^??2), as we show. In this work, we evaluate the potential detectability of Earth analogs orbiting around nearby M-type stars by monitoring the variability of the Lyα flux variability. We show that, in spite of the interstellar, heliospheric and astrospheric absorption, the transit signature in M5 V type stars would be detectable with a dedicated Lyα flux monitor implemented in a 4–8 m class space telescope. Such monitoring programs would enable measuring the robustness of planetary atmospheres under heavy space weather conditions like those produced by M-type stars. A 2-m class telescope, such as the World Space Observatory, would suffice to detect an Earth-like planet orbiting around Proxima Centauri, if there was such a planet or nearby M5 type stars.  相似文献   

Feeling at Home from A Distance? How Geographical Distance and Non-Residency Shape Sense of Place among Private Forest Owners     

Sabina Bergstén  E. Carina H. Keskitalo 《社会与自然资源》2019,32(2):184-203

Out-migration from rural areas and generational shifts create conditions whereby increasing numbers of private forest owners live at a distance from their forestland. Geographical distance and non-residency have been raised as issues that may possibly weaken these owners’ relationships with their properties. Drawing on the “sense of place” concept as a frame of analysis for 51 qualitative interviews with resident and nonresident private forest owners from two areas in Sweden, this study provides in-depth understanding of how geographical distance and place of residency shape owners’ feelings about their forest properties. The study shows that sense of place is constructed in complex and multifaceted ways over time and that social and historical contexts and processes beyond the forest environment can make owners feel closeness to their distant properties. Thus, geographical distance or residency alone does not explain variations in these forest owners’ feelings of distance or closeness to their properties.  相似文献