Spatial variations of field polarization and phase in microwave cavities: application to the cesium fountain cavity

A. Khursheed; G. Vecchi; A. De Marchi

doi:10.1109/58.485946

Spatial variations of field polarization and phase in microwave cavities: application to the cesium fountain cavity

IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control ◽

10.1109/58.485946 ◽

1996 ◽

Vol 43 (2) ◽

pp. 201-210 ◽

Cited By ~ 14

Author(s):

A. Khursheed ◽

G. Vecchi ◽

A. De Marchi

Keyword(s):

Spatial Variations ◽

Microwave Cavities ◽

Field Polarization

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Spatial variations of field polarization and phase in microwave cavities: application to the cesium fountain cavity

Proceedings of Conference on Precision Electromagnetic Measurements Digest ◽

10.1109/cpem.1994.333323 ◽

2002 ◽

Cited By ~ 1

Author(s):

A. Khursheed ◽

G. Vecchi ◽

A. De Marchi

Keyword(s):

Spatial Variations ◽

Microwave Cavities ◽

Field Polarization

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Contribution of large bacteria to bacterial biomass in a deep freshwater lake (Lake Biwa, Japan)

Aquatic Microbial Ecology ◽

10.3354/ame01949 ◽

2020 ◽

Vol 85 ◽

pp. 131-139

Author(s):

S Shen ◽

Y Shimizu

Keyword(s):

Cell Volume ◽

Bacterial Cell ◽

Lake Biwa ◽

Bacterial Biomass ◽

Spatial Variations ◽

Freshwater Lake ◽

Heterotrophic Nanoflagellates ◽

Bacterial Productivity ◽

Transmission Electron ◽

Seasonal And Spatial Variations

Despite the importance of bacterial cell volume in microbial ecology in aquatic environments, literature regarding the effects of seasonal and spatial variations on bacterial cell volume remains scarce. We used transmission electron microscopy to examine seasonal and spatial variations in bacterial cell size for 18 mo in 2 layers (epilimnion 0.5 m and hypolimnion 60 m) of Lake Biwa, Japan, a large and deep freshwater lake. During the stratified period, we found that the bacterial cell volume in the hypolimnion ranged from 0.017 to 0.12 µm3 (median), whereas that in the epilimnion was less variable (0.016 to 0.033 µm3, median) and much lower than that in the hypolimnion. Additionally, in the hypolimnion, cell volume during the stratified period was greater than that during the mixing period (up to 5.7-fold). These differences in cell volume resulted in comparable bacterial biomass in the hypolimnion and epilimnion, despite the fact that there was lower bacterial abundance in the hypolimnion than in the epilimnion. We also found that the biomass of larger bacteria, which are not likely to be grazed by heterotrophic nanoflagellates, increased in the hypolimnion during the stratified period. Our data suggest that estimation of carbon flux (e.g. bacterial productivity) needs to be interpreted cautiously when cell volume is used as a constant parametric value. In deep freshwater lakes, a difference in cell volume with seasonal and spatial variation may largely affect estimations.

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