Contributing Factors to Disease Outbreaks Associated with Untreated Groundwater   总被引：1，自引：0，他引：1  

Erika K. Wallender  Elizabeth C. Ailes  Jonathan S. Yoder  Virginia A. Roberts  Joan M. Brunkard 《Ground water》2014,52(6):886-897

Disease outbreaks associated with drinking water drawn from untreated groundwater sources represent a substantial proportion (30.3%) of the 818 drinking water outbreaks reported to CDC's Waterborne Disease and Outbreak Surveillance System (WBDOSS) during 1971 to 2008. The objectives of this study were to identify underlying contributing factors, suggest improvements for data collection during outbreaks, and inform outbreak prevention efforts. Two researchers independently reviewed all qualifying outbreak reports (1971 to 2008), assigned contributing factors and abstracted additional information (e.g., cases, etiology, and water system attributes). The 248 outbreaks resulted in at least 23,478 cases of illness, 390 hospitalizations, and 13 deaths. The majority of outbreaks had an unidentified etiology (n = 135, 54.4%). When identified, the primary etiologies were hepatitis A virus (n = 21, 8.5%), Shigella spp. (n = 20, 8.1%), and Giardia intestinalis (n = 14, 5.7%). Among the 172 (69.4%) outbreaks with contributing factor data available, the leading contamination sources included human sewage (n = 57, 33.1%), animal contamination (n = 16, 9.3%), and contamination entering via the distribution system (n = 12, 7.0%). Groundwater contamination was most often facilitated by improper design, maintenance or location of the water source or nearby waste water disposal system (i.e., septic tank; n = 116, 67.4%). Other contributing factors included rapid pathogen transport through hydrogeologic formations (e.g., karst limestone; n = 45, 26.2%) and preceding heavy rainfall or flooding (n = 36, 20.9%). This analysis underscores the importance of identifying untreated groundwater system vulnerabilities through frequent inspection and routine maintenance, as recommended by protective regulations such as Environmental Protection Agency's (EPA's) Groundwater Rule, and the need for special consideration of the local hydrogeology.  相似文献   

Potential climate change impacts on the probability of wind damage in a south Swedish forest     

Kristina Blennow  Mikael Andersson  Johan Bergh  Ola Sallnäs  Erika Olofsson 《Climatic change》2010,99(1-2):261-278

We estimated how the possible changes in wind climate and state of the forest due to climate change may affect the probability of exceeding critical wind speeds expected to cause wind damage within a forest management unit located in Southern Sweden. The topography of the management unit was relatively gentle and the forests were dominated by Norway spruce (Picea abies (L.) Karst.). We incorporated a model relating the site index (SI) to the site productivity into the forest projection model FTM. Using estimated changes in the net primary production (NPP) due to climate change and assuming a relative change in NPP equal to a relative change in the site productivity, we simulated possible future states of the forest under gradual adjustment of SI in response to climate change. We estimated changes in NPP by combining the boreal-adapted BIOMASS model with four regional climate change scenarios calculated using the RCAO model for the period 2071–2100 and two control period scenarios for the period 1961–1990. The modified WINDA model was used to calculate the probability of wind damage for individual forest stands in simulated future states of the forest. The climate change scenarios used represent non-extreme projections on a 100-year time scale in terms of global mean warming. A 15–40% increase in NPP was estimated to result from climate change until the period 2071–2100. Increasing sensitivity of the forest to wind was indicated when the management rules of today were applied. A greater proportion of the calculated change in probability of wind damage was due to changes in wind climate than to changes in the sensitivity of the forest to wind. While regional climate scenarios based on the HadAM3H general circulation model (GCM) indicated no change (SRES A2 emission scenario) or a slightly reduced (SRES B2 emission scenario) probability of wind damage, scenarios based on the ECHAM4/OPYC3 GCM indicated increased probability of wind damage. The assessment should, however, be reviewed as the simulation of forest growth under climate change as well as climate change scenarios are refined.  相似文献   

The probability of wind damage in forestry under a changed wind climate   总被引：1，自引：0，他引：1  

Kristina Blennow  Erika Olofsson 《Climatic change》2008,87(3-4):347-360

We (1) estimated how the possible changes in wind climate due to climatic change may affect the probability of exceeding critical wind speeds (CWS) expected to cause significant wind damage within a forest management unit located in southern Sweden, (2) analysed how the probability of exceeding an approximate CWS as observed in the management unit would change in different regions in Sweden if expecting a similar kind of forested area to occur in different geographical locations. The topography of the management unit was relatively gentle and the forests were dominated by Norway spruce (Picea abies (L.) Karst.). Seven regions across Sweden were selected for comparison of possible future probability of damaging wind speed. The model-system WINDA was modified and used for calculations of the probability of wind damage together with regionally downscaled climate change scenario (CCS) data. In total, two climate scenarios downscaled using the RCAO model for the control period 1961–1990 and four for the period 2071–2100 were used. The CCSs represent fairly central projections on a 100-year time scale in terms of global mean warming. Although there is ambiguity between different CCSs, the results indicated that the present pattern of more windy conditions in southern than in northern Sweden will remain. For most sites the probability of exceeding the CWS from westerly to south-westerly directions was indicated to remain comparatively high and the probability of damaging wind from south-westerly to south-easterly directions was indicated to increase in many places. For southernmost Sweden increasing probability of exceeding the CWS from the north-westerly to south-easterly wind directions were indicated for all but one CCS. The results were discussed with respect to spatial planning in forestry under a changing wind climate.  相似文献   

Anthrosols in Iron Age Shetland: Implications for arable and economic activity     

Erika B. Guttmann  Ian A. Simpson  Nina Nielsen  Stephen J. Dockrill 《Geoarchaeology》2008,23(6):799-823

The soils surrounding three Iron Age settlements on South Mainland, Shetland, were sampled and compared for indicators of soil amendment. Two of the sites (Old Scatness and Jarlshof) were on lower‐lying, better‐drained, sheltered land; the third (Clevigarth) was in an acid, exposed environment at a higher elevation. The hypothesis, based on previous regional assessments, soil thicknesses, and excavations at Old Scatness, was that the lowland sites would have heavily fertilized soils and that the thin upland soil would show little if any amendment. Our findings indicate that the Middle Iron Age soils at Old Scatness had extremely high phosphorus levels, while the soil at Jarlshof had lower levels of enhancement. At Clevigarth, where charcoal from the buried soil was 14C dated to the Neolithic and Bronze Age, there was no evidence of arable activity or soil amendment associated with the Iron Age phases of settlement. These observations indicate that not all sites put the same amount of effort into creating rich arable soils. The three sites had very different agricultural capacities, which suggests the emergence of local trade in agricultural commodities in Iron Age Shetland. © 2008 Wiley Periodicals, Inc.  相似文献   

Zeittafel     

W. F. de Jong  Erika Stradner 《Mineralogy and Petrology》1956,5(4):362-379

Ohne Zusammenfassung  相似文献   

Nachweis und Bestimmung geringster Nikotinkonzentrationen in Wasserproben     

H. R. Hegi  Erika Fischer  Erwin Märki 《Aquatic Sciences - Research Across Boundaries》1964,26(1):91-101

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The distribution of Fe2+ and Fe3+ in iron-bearing tourmalines: A Mössbauer study     

Dr. Erika Hermon  Prof. D. J. Simkin  Prof. Gabrielle Donnay  Prof. W. B. Muir 《Mineralogy and Petrology》1973,19(2):124-132

Summary Room-temperature Mössbauer spectra of five iron-bearing tourmalines were measured and analyzed. The Fe²⁺/Fe³⁺ ratio and the iron occupancy of the Y and Z positions could be assigned to all samples, with the help of two previously well characterized samples, from Mexico and Madagascar. Ferric or ferrous ions or both partially occupy the Z as well as the Y octahedra. This fact of observation is interpreted as the chemical response, during crystal growth, to the requirement of size matching for the edge-sharing Y and Z oxygen octahedra. It accounts for the inexistence of solid solution between the Mg and (Li, Al) tourmalines.

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Die Verteilung von Fe²⁺ und Fe³⁺ in eisenhaltigen Turmalinen: Eine Mössbauer-Untersuchung

Zusammenfassung Mössbauer-Spektren von fünf eisenhaltigen Turmalinen wurden gemessen und analysiert. Das Verhältnis Fe²⁺/Fe³⁺ und die Eisenverteilung konnten mit Hilfe von zwei gut identifizierten Turmalin-Kristallen von Mexiko und Madagascar für die Y-und Z-Lagen aller Exemplare bestimmt werden. Zweiwertiges sowie dreiwertiges Eisen findet sich sowohl in der Z-als auch in der Y-Lage. Da sich die Y-und Z-Oktaeder in einer gemeinsamen Kante treffen, wird diese Beobachtung als chemische Antwort des Kristalles auf die erforderte Größenanpassung der Y-und Z-Oktaeder während seines Wachstums erklärt. Die Abwesenheit der festen Lösung zwischen Dravit und Elbait kann somit erklärt werden.

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With 4 Figures  相似文献   

Der “Protocalcit” von Gumpoldskirchen (Niederösterreich)     

E. Schroll  Erika Stepán  W. Geymayer  H. Horn 《Mineralogy and Petrology》1965,10(1-4):573-585

Zusammenfassung In einem in Abbau befindlichen Steinbruch bei Gumpoldskirchen (Niederösterreich) wurde in Fugen und Hohlräumen eines Störungssystems von Hauptdolomit als rezente Verwitterungsbildung des Gesteins ein weißes, gelartiges Mineral aufgefunden, das einen Gehalt von mehr als 90% lose gebundenes Wasser aufweist. An der Luft trocknet die quallige Mineralbildung zu einem papierartigen Häutchen (Bergmilch oder Papierspat) und rekristallisiert unter natürlichen Bedingungen zu erdigen, weißen Krusten (Bergmehl). Die chemische Analyse, die Röntgendiffraktionsanalyse und Elektronenbeugungsaufnahmen zeigen einwandfrei, daß es sich, auch im wasserhaltigen Zustand, um Calciumcarbonat in der Modifikation des Calcites handelt. Die elektronenmikroskopischen Aufnahmen erklären die Eigenschaften dieser Mineralbildung. Im wasserhaltigen Zustand sind wirrgelagerte Calcitfäden zu erkennen, deren Durchmesser ca. 500 Å beträgt. Das Wasser ist im Calcitfadengerüst als grobe Feuchtigkeit gebunden. Für die wasserhaltige Varietät (CaCO₃+xH₂O) wird der Name Protocalcit vorgeschlagen.

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Summary A white gel-like mineral containing more than 90% moisture was found in a quarry near Gumpoldskirchen (Lower Austria). The mineral had been formed recently in gaps and cavities of a fissure system in the Triassic Main Dolomite.Airdried, the jelly mineral turns into a paper-like skin (rockmilk) and can be recrystallised to a white earthy crust (rockflour).The chemical analysis, the X-ray diffraction and electron diffraction investigation show that the mineral is calcite, even it contains high amounts of water. The electronmicroscopical investigations explain the properties of this peculiar formation of the mineral. If the mineral is containing water, the filiform crystallites of calcite 500 Å of diameter are completely disorderd. The water is bound adsorptively in the framework of calcite crystallites. During the loss of water the filiform calcite crystalls are ordered more or less parallel to each other.The name protocalcite is proposed for this variety of calcite, which is containing variable amounts of water (CaCO₃+xH₂O).

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Mit 9 Textabbildungen

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Herrn Professor Dr.F. Machatschki zum 70. Geburtstag gewidmet.  相似文献   

Soft-sediment deformation structures in Late Miocene–Pleistocene sediments on the pediment of the Mátra Hills (Visonta, Atkár, Verseg): Cryoturbation, load structures or seismites?     

Zolt  n Horv  th  Erika Mich  li  Andrea Mindszenty  Judit Ber  nyi-Ü  veges 《Tectonophysics》2005,410(1-4):81-95

The studied area, built up by silty clayey and partly sandy sediments and paleosols, lies on the tectonically active Northern margins of the Pannonian Basin. Wavy, sagging load casts can be observed in the upper part of the Late Miocene alluvial complex and larger scale sagging load casts, flame structures, drops and pillows detected in its Quaternary cover were studied in detail, in order to understand the origins of soft sediment deformation which characterized this young sedimentary suite. Sedimentological, paleopedological and mineralogical observations suggest that:

1. One of the reasons for the soft-sediment deformation might have been the relatively low cohesive strength of the predominantly smectitic sediment covering a gentle slope similar to the actual landscape.

2. On such a surface, the down-slope gravitational component of the mud-blanket might easily have been sufficient to overcome its cohesive strength.

3. Frost action traceable in the studied formations might also have contributed to the observed deformation, particularly along the eroded top of the Late Miocene sediments.

Combined evidence from field observations and laboratory analyses support the idea that liquefaction–fluidization was of prime importance in bringing about the observed structures. In conclusion two alternative Quaternary/Holocene scenarios are proposed, which might have resulted in the unusual behaviour of the sediments/paleosols. One is a seismic event, the other is the combined effect of freeze–thaw cycles and of the sloping foothill position, which might have resulted in episodic downslope transport and the associated deformation of the eroded soil material when its water content surpassed a certain threshold. We accept that the anomalous abundance of soft-sediment deformation in this marginal position may be causally related to paleo-earthquakes, but the obvious complexity of the phenomenon requires caution. In case the proposed scenarios would not have been alternatives but acted simultaneously, the analysed phenomena were to be interpreted as the joint results of tectonics and climate change.  相似文献   

The Footprint Database and Web Services of the Herschel Space Observatory     

László Dobos  Erika Varga-Verebélyi  Eva Verdugo  David Teyssier  Katrina Exter  Ivan Valtchanov  Tamás Budavári  Csaba Kiss 《Experimental Astronomy》2016,42(2):139-164

Data from the Herschel Space Observatory is freely available to the public but no uniformly processed catalogue of the observations has been published so far. To date, the Herschel Science Archive does not contain the exact sky coverage (footprint) of individual observations and supports search for measurements based on bounding circles only. Drawing on previous experience in implementing footprint databases, we built the Herschel Footprint Database and Web Services for the Herschel Space Observatory to provide efficient search capabilities for typical astronomical queries. The database was designed with the following main goals in mind: (a) provide a unified data model for meta-data of all instruments and observational modes, (b) quickly find observations covering a selected object and its neighbourhood, (c) quickly find every observation in a larger area of the sky, (d) allow for finding solar system objects crossing observation fields. As a first step, we developed a unified data model of observations of all three Herschel instruments for all pointing and instrument modes. Then, using telescope pointing information and observational meta-data, we compiled a database of footprints. As opposed to methods using pixellation of the sphere, we represent sky coverage in an exact geometric form allowing for precise area calculations. For easier handling of Herschel observation footprints with rather complex shapes, two algorithms were implemented to reduce the outline. Furthermore, a new visualisation tool to plot footprints with various spherical projections was developed. Indexing of the footprints using Hierarchical Triangular Mesh makes it possible to quickly find observations based on sky coverage, time and meta-data. The database is accessible via a web site http://herschel.vo.elte.hu and also as a set of REST web service functions, which makes it readily usable from programming environments such as Python or IDL. The web service allows downloading footprint data in various formats including Virtual Observatory standards.  相似文献