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The use of charge-coupled devices is suggested as a means for detecting growth of micro-organism colonies. The accuracy of the method is determined by channel width and the sensitivity by the signal/noise ratio. The method was tested on a dense nutrient medium, which is to be considered more suitable to micro-organisms of the dry Martian soil than the water solution of nutrients employed in the Viking's strategy.  相似文献   
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The properties of quasiperiodic (QP), extremely low-frequency (ELF), and very low-frequency (VLF) emissions detected at a ground-based station in northern Finland between 15:00 UT and 22:00 UT on December 24, 2011 were studied. Characteristic periods in the spectra of QP emissions at different timescales and their dynamics during the considered event were analyzed. Two types of period variations of the QP emissions were observed: a regular increase of periods on timescales of 1 min to 2.5 min and appreciable period variations on a timescale of 1–10 min during substorms. These period variations are explained based on the properties of a self-oscillating cyclotron-instability regime in the magnetosphere. The analysis of the fine structure of the spectra of QP elements indicated that short-periodic modulations with periods of approximately 3 and 6 s were detected in the low-frequency part of the spectrum (f < 2.5 kHz) and in the high-frequency part of the spectrum (f > 2.5 kHz), respectively. The 6 s period corresponded to the period of two-hop propagation of whistling atmospherics. The presence of this short-periodic modulation may be related to the passive mode locking in a magnetospheric cyclotron maser.  相似文献   
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