Magnetotactic bacteria from the human gut microbiome associated with orientation and navigation regions of the brain     

Simon  Rozalyn A.  Ranasinghe  Purnika Damindi  Barazanji  Nawroz  Jungeström  Malin Bergman  Xu  Jie  Bednarska  Olga  Serrander  Lena  Engström  Maria  Bazylinski  Dennis A.  Keita  Åsa V.  Walter  Susanna 《中国海洋湖沼学报》2021,39(6):2044-2052

Journal of Oceanology and Limnology - Magnetotactic bacteria (MTB), ubiquitous in soil and fresh and saltwater sources have been identified in the microbiome of humans and many animals. MTB...  相似文献   

Intertidal meiofauna of Jeju Island,Korea     

Olga N. Pavlyuk  Yulia A. Trebukhova 《Ocean Science Journal》2011,46(1):1-11

For the first time, the structure of the meiobenthos community and marine nematodes in particular was investigated in the different intertidal zones of Jeju Island (South Sea of Korea). A relationship was found between the density of meiobenthic communities and the type of the bottom sediment. In addition, in the silty sediments, nematodes were dominant, while in the sandy sediments harpacticoids and ostracods were dominant groups. Sixty eight species belonging to 60 genera and 19 families of nematodes were found in the whole area. Four different nematode taxocenosis were distinguished using a cluster analysis. Dominant feeding groups were omnivores (2B) and epistratum-feeders (2A). The highest number of non-selective deposit-feeders (1B) was detected in the lagoon with the bottom silty sediments.  相似文献   

An assessment of the climate change impacts on groundwater recharge at a continental scale using a probabilistic approach with an ensemble of GCMs   总被引：1，自引：0，他引：1  

Russell S. Crosbie  Trevor Pickett  Freddie S. Mpelasoka  Geoff Hodgson  Stephen P. Charles  Olga V. Barron 《Climatic change》2013,117(1-2):41-53

This study used 16 Global Climate Models and three global warming scenarios to make projections of recharge under a 2050 climate for the entire Australian continent at a 0.05° grid resolution. The results from these 48 future climate variants have been fitted to a probability distribution to enable the results to be summarised and uncertainty quantified. The median results project a reduction in recharge across the west, centre and south of Australia and an increase in recharge across the north and a small area in the east of the continent. The range of results is quite large and for large parts of the continent encompasses both increases and decreases in recharge. This makes it difficult to utilise for water resources management so the results have been analysed with a risk analysis framework; this enables the future projections for groundwater recharge to be communicated to water managers in terms of likelihood and consequence of a reduction in recharge. This highlights an important message for water resource managers that in most areas of Australia they will be making decisions on water allocations under considerable uncertainty as to the direction and magnitude of recharge change under a future climate and that this uncertainty may be irreducible.  相似文献   

The finest white-light coronal features     

Serge Koutchmy  Olivier Bouchard  Jean Mouette  Olga Koutchmy 《Solar physics》1993,148(1):169-172

An attempt to detect the finest white-light coronal features observed with a large optical telescope was made at the July 11, 1991 Solar Total Eclipse. A few selected results taken from the video-CCD high speed observations obtained at the prime focus of the Canada-France-Hawaï-Telescope (CFHT) with a red coronal interference filter are presented. The smallest (sub-arsec) detected and/or resolved coronal features are shown. The methods that were used to extract them from the noisy and seeing-limited images taken from video frames are described.  相似文献   

Rest-frame optical continua of L∼L*, z > 3 quasars: probing the faint end of the high-z quasar luminosity function     

Olga P. Kuhn 《Monthly notices of the Royal Astronomical Society》2004,348(2):647-660

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Factors and mechanisms of chemical composition formation of saline lakes in West Mongolia     

Marina KOLPAKOVA  Stepan SHVARTSEV  Vitalyi ISUPOV  Sodov ARIUNBILEG  Alexander VLADIMIROV  Olga GASKOVA 《《地质学报》英文版》2014,88(Z1):142-144

正All the lakes are accumulative systems for the various chemical elements.However,the ratios of the elements in different lake types are very different.It is generally accepted that the composition of lake water determined by  相似文献   

Multi-methodological investigation of kunzite, hiddenite, alexandrite, elbaite and topaz, based on laser-induced breakdown spectroscopy and conventional analytical techniques for supporting mineralogical characterization     

Manuela Rossi  Marcella Dell’Aglio  Alessandro De Giacomo  Rosalba Gaudiuso  Giorgio Saverio Senesi  Olga De Pascale  Francesco Capitelli  Fabrizio Nestola  Maria Rosaria Ghiara 《Physics and Chemistry of Minerals》2014,41(2):127-140

Gem-quality alexandrite, hiddenite and kunzite, elbaite and topaz minerals were characterized through a multi-methodological investigation based on EMPA-WDS, LA-ICP-MS, and laser-induced breakdown spectroscopy (LIBS). With respect to the others, the latter technique enables a simultaneous multi-elemental composition without any sample preparation and the detection of light elements, such as Li, Be and B. The criteria for the choice of minerals were: (a) the presence of chromophore elements in minor contents and/or as traces; (b) the presence of light lithophile elements (Li, Be and B); (c) different crystal chemistry complexity. The results show that LIBS can be employed in mineralogical studies for the identification and characterization of minerals, and as a fast screening method to determine the chemical composition, including the chromophore and light lithophile elements.  相似文献   

Wind-induced sediment resuspension as a potential factor sustaining eutrophication in large and shallow Lake Peipsi   总被引：1，自引：0，他引：1  

Olga Tammeorg  Juha Niemistö  Tõnu Möls  Reet Laugaste  Kristel Panksep  Külli Kangur 《Aquatic Sciences - Research Across Boundaries》2013,75(4):559-570

Using sediment traps, we aimed to elucidate the temporal and spatial variations in sediment fluxes in large and shallow Lake Peipsi, over the May to October 2011 period, and analyze the factors behind those variations. The effects of weather factors (mean and maximum wind velocity, water level and water temperature) on sediment resuspension and the concentrations of suspended solids (SS), total phosphorus (TP), soluble reactive phosphorus (SRP), and chlorophyll a (Chl a) were investigated. Moreover, the internal loading of TP due to sediment resuspension was determined. The sediment resuspension rates were significantly higher in the shallower waters than in the deeper parts of the lake. Resuspension was a major factor in sedimentation dynamics of the lake, which is presently subject to eutrophication. The rates of sediment resuspension followed the same pattern as gross sedimentation during the study period, and their respective values differed significantly between sampling dates. The highest resuspension rates were observed in September (mean 55.4 g dw m^?2 day^?1), when the impacts of wind events were particularly pronounced. Weather factors that were recorded approximately 2 weeks before water and sediment sampling affected the gross sedimentation and sediment resuspension. The water quality variables of SS, TP, SRP, Chl a were similarly affected. During the study, TP concentrations of the water were mainly determined by the resuspension of sediments containing a large pool of organic material. Although internal loading of TP due to resuspension was several times greater than external loading, external loading determines the amount of phosphorus that enters the lake and can be resuspended.  相似文献   

Observing Gravity Change in the Fennoscandian Uplift Area with the Hanover Absolute Gravimeter     

Ludger Timmen  Olga Gitlein  Volker Klemann  Detlef Wolf 《Pure and Applied Geophysics》2012,169(8):1331-1342

The Nordic countries Norway, Sweden, Finland and Denmark are a key study region for research of glacial isostasy. In addition, such research offers a unique opportunity for absolute gravimetry to show its capability as a geodetic tool for geophysical research. Within a multi-national cooperation, annual absolute gravity measurements have been performed in Fennoscandia by IfE since 2003. For the Hanover gravimeter FG5-220, overall accuracy of ±30?nm/s² is indicated for a single station determination. First results of linear gravity changes are derived for ten stations in the central and southern part of the uplift area. Comparing with the rates predicted by glacial rebound modelling, the gravity trends of the absolute measurements differ by 3.8?nm/s² per year (root-mean-square discrepancy) from the uplift model. The mean difference between observed and predicted rates is 0.8?nm/s² per year only. A proportionality factor of ?1.63?±?0.20?nm/s² per mm has been obtained, which describes the mean ratio between the observational gravity and height rates.  相似文献   

The application of an indirect electromagnetic geothermometer to temperature extrapolation in depth     

Viacheslav V. Spichak  Olga K. Zakharova 《Geophysical Prospecting》2009,57(4):653-664

We study the feasibility of the application of an indirect EM geothermometer, developed recently, to the temperature extrapolation in depth using magnetotelluric data collected in the seismically active northern Tien Shan faulted area (Bishkek Geodynamic Test Site, Kyrgyzstan) and Hengill geothermal zone (Iceland). The approach used is based on the artificial neural network technique, which does not imply the prior knowledge of the electrical conductivity mechanisms on the one hand and provides temperature estimates based on the analysis of the implicit conductivity-temperature relations, on the other.
The samples for neuronet teaching consisted in the well temperature records and electrical conductivity values determined for the same depths from the magnetotelluric data measured in the vicinities of eight boreholes in each testing area. The testing of the taught neuronets was carried out using the temperature records not involved in the teaching process. The results indicate that the temperature extrapolation accuracy essentially depends on the ratio between the well length and the extrapolation depth. In particular, in extrapolation to a depth twice as large as the well depth the relative error is 5–6% and in case of threefold excess, the error is around 20%. This result makes it possible to increase significantly the depth of indirect temperature estimation in the Earth's interior (in particular, for geothermal exploration) based on the available temperature logs.
The practical application of an indirect electromagnetic geothermometer could provide the following facilities: 1) more exact temperature estimation in the extrapolation mode; 2) remote temperature estimates in the boreholes in areas characterized by extreme conditions for conventional geothermometers.  相似文献