Технология и свойства пористого гранулированного стеклокристаллического материала из высокодисперсного кремнеземистого сырья

This paper reports on the regional screening, selection and geological characterisation of a potential on-shore CO2 storage site (saline aquifer) in north-eastern Germany. The main objective of this study was to identify and investigate a candidate storage site, capable to accommodate the total amount of approximately 400 million tons of CO2. Such a volume is produced by a modern, lignite-fired power plant within its operation lifetime of approximately 40 years. Within north-eastern Germany, several saline aquifers of Triassic, Jurassic and Cretaceous age have been evaluated with respect to their regional occurrence, storage potential and basic reservoir properties. Subsequent to a ranking, considering different criteria, the anticlinal structure Schweinrich holding suitable saline aquifers of the uppermost Triassic and lowest Jurassic has been selected from a number of identified candidate sites. According to results of the geological site characterisation, including structural geological investigations and 3D reservoir modelling, the structure Schweinrich seems to be a suitable site for industrial large scale CO2 storage. Further data acquisition (new wells and 3D seismics) and research (more detailed and comprehensive modelling) is needed in order to prove the structural integrity of the storage site and assure long-term safety. © 2007 Springer-Verlag

Photosystem II electron flow as a measure for phytoplankton gross primary production = [Fotosysteem II elektronentransport als een maat voor de bruto primaire produktie van fytoplankton]

Saturating pulse fluorescence measurements, well known from studies of higher plants for determination of photosystem II (PS II) characteristics, were applied to cultures of the green alga Dunaliella teitiolecta (Chapter 2). The actual efficiency of PS II (φ PS II ), the maximal efficiency of PS II (F v /F m ), and both photochemical and non- photochemical fluorescence quenching were determined for cultures of D. tertiolecta growing under varying light intensities. The rate of PS II electron flow (J E ) estimated as the product of φ PS II , and the photon flux density (PFD), appeared to correlate well with growth rates determined for the D. tertiolecta cultures . The results indicated that the saturating pulse fluorescence method may be successfully used to determine photosynthetic characteristics of phytoplankton. However, an increase of sensitivity by a factor 1000 was found to be needed for the application of this technique to in situ measurements. Conditions were outlined which have led to the development of the Xe-PAM fluorometer with a manyfold higher sensitivity.The relation between photosynthetic oxygen evolution (J 0 , expressed as oxygen production per chlorophyll a ) and J E was investigated for the marine algae Phaeodactylum tricornutum, D. tertiolecta, Tetraselmis sp., Isochrysis sp. and Rhodomonas sp , by varying the ambient PFD (Chapter 3). At limiting light a linear relation was found in all species. At PFD's approaching light saturation linearity was lost. The observed non-linearity at high M's is most probably not caused by photorespiration but by a Mehler-type of oxygen reduction. The relationship could be modelled by including a redox-state dependent oxygen uptake. The linear range between J E and J 0 extends to a PFD which is 2 to 10 times higher than the PFD at which the species were grown. The ratio of J E and J 0 in the light-limited range is species dependent and related to differences in absorption cross-section of PS II (σ PS II ). The ratio of J E and J 0 in the light-limited range is not dependent on temperature. F v /F m was found to be temperature dependent with an optimum near 10 °C in the diatom P. tricornutum .The photosynthetic electron flux in a phytoplankton sample (PEF) was shown to depend on the product of J E (= φ PS II · PFD), σ PS II and the number of PS II (n PS II ) in the sample (Chapter 4). A mathematical expression was derived which relates the minimal fluorescence (F 0 ) to n PS II and σ PS II under the condition that the spectral distribution of the ambient light and the measuring light are identical. This condition can be approximated measuring F 0 with the Xe-PAM fluorometer. The experimental conditions under which the relationship between PEF, φ PS II , and F 0 is valid, were examined. The maximal value of φ PS II (F v /F m ) was shown to be independent on the wavelength under the measuring conditions. The apparent F v /F m depends on the intensity of the measuring light and the duration and intensity of the saturating light pulse. It is shown that, under certain conditions, the minimal fluorescence can be used as a measure of PS II excitation in the light. F 0 , obtained with the broad band excitation light of a filtered Xenon flash lamp, thus was used as a measure for the product of n PS II and σ PS II . The relationship between PEF calculated with this expression and net oxygen evolution (phytoplankton oxygen flux, POF, expressed as oxygen production per sample volume) was found to be similar in the diatom P tricornutum and the green alga D. tertiolecta. Therefore we conclude that the use of PEF as a measure for POF yields better results than the use of J E for J 0 . The Xe-PAM fluorometer was found to be sensitive enough for coastal applications.The relation between PEF and carbon fixation (phytoplankton carbon flux, PCF, expressed as the carbon dioxide fixed per sample volume) was examined in cultures of Isochrysis sp. , Phaeocystis sp. macroflagellates and Skeletonema costatum (Chapter 5). The F 0 used to calculate PEF was measured at the start of the experiments. Both the PFD and the duration of the incubation were varied. As found before for the relation between J E and J 0 , the relation between PEF and PCF was also approximately linear at limiting light and deviated from linearity at saturating light. The linear range between PCF and PEF also extends to a PFD which is 2 to 10 times higher than the PFD at which the species were grown. The length of the incubation did not affect PEF and PCF except for the highest PFD (1530 μmol m -2s -1). The decline of F v /F m of the samples irradiated at the highest PFD showed a fast component within 30 minutes incubation and a minor slow component, indicating that photoinhibition was induced in the first 30 minutes.PEF, PCF, oxygen production and their relationships were furthermore examined during phytoplankton development in a mesocosm at the field station (Chapter 6). PEF was calculated from F 0 , φ PS II and the PFD which were continuously monitored for three weeks in the upper water layer of the mesocosm. In addition PEF and PCF were estimated from laboratory measurements on samples taken from the mesocosms. Daily primary production in the mesocosm, measured as either PSII electron flow (PPE) or carbon fixation (PPC), was calculated using a photosynthesis model. Daily photosynthetic oxygen evolution (PPO) was calculated from changes in the oxygen concentration over the day. In the period between the 2 blooms the ration of PPO and PPE was higher than during the peak of the blooms. The ratio of PPC and PPE was much more constant. In general PPE gave a reasonable measure of both PPC and PPO.The effects of chlororespiration and state transitions on F 0 were determined in the diatom P. tricornutum (Chapter 7). Inhibition of chlororespiration by antimycin A or anaerobiosis did not affect F v /F m . The observed F 0 was insignificantly (8%) increased upon addition of antimycin A and slightly decreased upon illumination with farred light (6 μmol m -2s -1). These effects might be attributed to chlororespiratory activity, but could as well be caused by reduction of Q A by the weak fluorescence measuring light. Addition of the uncouplers CCCP or nigericin did not increase the maximal fluorescence (F M ). The data show that under our conditions reduction of Q A and energy dependent quenching in the dark by chlororespiration do not occur in P. tricornutum . Light-induced increases in F M , therefore, are suggested to be caused by state transitions. Use of the F 0 to estimate photon capture in the light might lead to an underestimation of the PEF The error is estimated to be not more than about 10 % as calculated from the increase in maximal fluorescence in the light.The present work illustrates that the fluorescence pulse method is a reliable technique to get insight into the photosynthetic performance and gross primary production of the population of algal cells in a marine ecosystem

Modern and fossil non-pollen palynomorphs from the Basque mountains (western Pyrenees, France): the use of coprophilous fungi to reconstruct pastoral activity

International audienceThis paper presents results from a modern dataset of non-pollen palynomorphs and its application to aca. 2,000 year peat record from the same area in the western Pyrenees (Basque Country, France). The modern dataset is composed of 35 surface samples (moss polsters) from a mountainous pasture-woodland landscape. Airborne fungal spores (ascospores and conidia), found dominant in the dataset, are linked to the degree of landscape openness and grazing pressure. The complete spectrum of 13 selected spore-types of dung-related Ascomycetes is positively linked with grazing pressure. However, different dung affinities between the spore-types have been identified. These are types clearly related to high grazing pressure and types with no or unclear dung indicative value. The modern dataset is used to aid interpretation of the local fossil pollen record as an independent 'proxy' to assess past pastoral dynamics. This study confirms the utility of modern nonpollen palynomorphs from terrestrial ecosystems in the reconstruction of historical local pastoral activities but also shows their limitation. It may be necessary to extend such study to wetland ecosystems and to investigate the spatial dimension of some fungal spores

Linking forest cover, soil erosion and mire hydrology to late-Holocene human activity and climate in NW Spain

This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 3.0 License (http://www.creativecommons.org/licenses/by-nc/3.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page (http://www.uk.sagepub.com/aboutus/openaccess.htm).This article has been made available through the Brunel Open Access Publishing Fund.Forest clearance is one of the main drivers of soil erosion and hydrological changes in mires, although climate may also play a significant role. Because of the wide range of factors involved, understanding these complex links requires long-term multi-proxy approaches and research on the best proxies to focus. A peat core from NW Spain (Cruz do Bocelo mire), spanning the last ~3000 years, has been studied at high resolution by physical (density and loss on ignition (LOI)), geochemical (elemental composition) and palynological (pollen and non-pollen palynomorphs) analyses. Proxies related to mineral matter fluxes from the catchment (lithogenic tracers, Glomus and Entorrhiza), rainfall (Bromine), mire hydrology (HdV-18), human pressure (Cerealia-type, nitrophilous taxa and coprophilous fungi) and forest cover (mesophilous tree taxa) were the most useful to reconstruct the evolution of the mire and its catchment. Forest clearance for farming was one of the main drivers of environmental change from at least the local Iron Age (~2685 cal. yr BP) onwards. The most intense phase of deforestation occurred during Roman and Germanic times and the late Middle Ages. During these phases, the entire catchment was affected, resulting in enhanced soil erosion and severe hydrological modifications of the mire. Climate, especially rainfall, may have also accelerated these processes during wetter periods. However, it is noteworthy that the hydrology of the mire seems to have been insensitive to rainfall variations when mesophilous forest dominated. Abrupt changes were only detected once intense forest clearance commenced during the Iron Age/Roman transition (~2190 cal. yr BP) phase, which represented a tipping point in catchment's ability to buffer impacts. Overall, our findings highlight the importance of studying ecosystems' long-term trajectories and catchment-wide processes when implementing mire habitat protection measures.This work was funded by the projects CGL2010-20672 (Plan Nacional I+D+i, Spanish Ministry of Science and Innovation) and 10PXIB200182PR (General Directorate of I+D, Xunta de Galicia). N Silva-Sánchez and L López-Merino are currently supported by a FPU predoctoral scholarship (AP2010-3264) funded by the Spanish Government and a MINT postdoctoral fellowship funded by the Brunel Institute for the Environment, respectively

Does experience influence the forces exerted on maxillary incisors during laryngoscopy? A manikin study using the Macintosh laryngoscope

The influence of the level of experience of the laryngoscopist on the duration of laryngoscopy, the forces exerted on the tongue and on the maxillary incisors during laryngoscopy, were investigated. Five groups (anaesthetists, residents in anaesthesia, nurse anaesthetists, surgeons and medical students), each consisting of 15 individuals, participated in the study. An intubation manikin was used with a laryngoscope modified so that the forces applied during laryngoscopy could be measured. The mean duration of laryngoscopy in these groups was 23.4 sec, 17.6 sec, 27.1 sec, 26.8 sec and 42.7 sec, respectively. The maximally applied forces on the tongue were 71.7 N, 60.5 N, 65.9 N, 74.2 N and 69.7 N, respectively. The maximally applied forces on the maxillary incisors were 49.9 N, 36.3 N, 41.1 N, 58.3 N and 53.9 N, respectively. These results indicate the level of experience has a significant influence on the duration of laryngoscopy but seems to have little influence on the forces applied to the tongue and the maxillary incisors

Ontwikkeling van geleide bemestingssystemen bij de teelt van zetmeelaardappelen 2002-2003

In het project “Ontwikkeling van geleide bemestingssystemen” worden verschillende systemen van geleide bemesting voor stikstof in veldproeven vergeleken en verder ontwikkeld. In dit kader heeft het Praktijkonderzoek Plant en Omgeving (PPO) in samenwerking met Plant Research International (PRI) in 2002 en 2003 een proef uitgevoerd in zetmeelaardappelen op Noordoostelijke zandgrond op proefboerderij Kooijenbur