Search results for "dBc"
showing 3 items of 3 documents
Plant micro-reserves in Valencia (E. Spain): A model to preserve threatened flora in China?
2017
The Valencian Community (eastern Spain) was the pioneer territory establishing plant micro-reserves (PMRs). Its model to protect small sites for endemic and endangered plants has been exported to several countries around the globe. This paper highlights 1) the role of PMRs to complement the protection provided by large protected areas, 2) how the establishment of PMRs fosters the increase of floristic knowledge, and 3) the fact that continuous monitoring of PMRs also yields new records of endangered species found within the same PMRs. The flexibility of the PMR approach -it can be adapted to other national and regional legislations- allows its transfer to other rich-biodiversity regions and…
Expression of retinoic acid nuclear receptors in the mouse embryonal carcinoma cell line PCC7-Mz1
1992
Mouse embryonal carcinoma cell line PCC7-Mz1 can serve as a model of mammalian neural development [1989, J. Cell. Biol. 109, 2481-2493]. Upon exposure to all-trans retinoic acid (RA), Mz1 cells differentiate into a stable pattern of neurons, astroglia and fibroblasts whereas variants of the parental cell line either are restricted in their patterns of derivatives or do not respond at all to RA. Using gene probes specific for the alpha 1, alpha 2 and beta 2 isoforms of the retinoic acid nuclear receptor, we have studied by Northern blot analysis the expression of these transcription factors in uninduced and induced cells of clone Mz1 and in variants with different developmental potential. al…
A low phase noise microwave source for high‐performance CPT Rb atomic clock
2021
Abstract Phase noise of the frequency synthesizer is one of the main limitations to the short‐term stability of microwave atomic clocks. Here, a low‐noise, simple‐architecture microwave frequency synthesizer for a coherent population trapping (CPT) clock is demonstrated. The synthesizer is mainly composed of a 100 MHz oven‐controlled crystal oscillator (OCXO), a microwave comb generator, and a direct digital synthesizer (DDS). The absolute phase noises of 3.417 GHz signal are measured to be −55 dBc/Hz, −81 dBc/Hz, −111 dBc/Hz and −134 dBc/Hz, respectively, for 1 Hz, 10 Hz, 100 Hz and 1 kHz offset frequencies, which shows only 1 dB deterioration at the second harmonic of the modulation frequ…