With increasing proportion of wind power integrated in the power system, operation simulation analysis has become an important tool for power system planning and operation. This paper presents a ...statistical modeling scheme for the stochastic time series of multiple wind farms power considering both the temporal patterns and the spatial correlation. The proposed composite spatiotemporal Markov process model is composed of a temporal Markov process with inter-day modal transfer, and multiple spatial Markov processes to reflect the correlation among wind farms. Evaluation on the simulation results through statistical metrics showed the feasibility and performance of the proposed scheme.
Due to the threat of lead pollution to health, environmental and food safety, developing simple and fast detection methods is highly required. Whereas, traditional single-mode probe suffers from ...limited application scenario. In this study, a colorimetric and fluorometric dual-mode probe for Pb
determination was constructed by using bifunctional G-quadruplex-hemin complex. In this dual-mode probe, enzyme strand and substrate strand of 8-17 DNAzyme are labeled with G-quadruplex-hemin complex and fluorophore, respectively. In the absence of Pb
, the self-assembly of enzyme strand and substrate strand inhibits intrinsic mimic peroxidase of G-quadruplex-hemin complex by base-pairing, which also quench the fluorescence via in proximity effect. When the DNAzyme is activated by Pb
, the quenched fluorescence is restored as well as the inherent peroxidase mimetic activity, leading to dual signal output. Under optimal conditions, this dual-mode probe exhibit a good linear relationship between logarithm of Pb
concentration and signal difference within the range from 1.5 nM to 20 nM and 0.5 nM to 10 nM for colorimetric and fluorescence mode, respectively. The detection limits for the corresponding mode were estimated to be 1.29 nM and 0.16 nM, respectively. This dual-mode probe also successfully applied for the spiked river water assay with satisfactory recovery in the range of 93.2 %-115.3 %. This work paves a new way for DNAzyme based dual-mode probe construction.
This paper is aimed to analyze Whiteleg shrimp's (Penaeus vannamei's) acoustic behavior collected in a farming pond. According to artificial feeding events, the chewing sound from shrimps is obtained ...by a passive acoustic recorder. The sound pressure level of the 1-minute segments between the two feedings is lower than that of after feeding, but higher than that of before feeding. There are two changing parts in the spectrum of several segments, in which one type has a low-frequency energy mainly in 2kHz, and the other has a high frequency energy in 4-15kHz. It is related to shrimps chewing behavior with a large number of 'click' signals. By analyzing the chewing sound from individual shrimp, time length of the signal is around 0.01s and the frequency range is about 4-15kHz. The behavior corresponding to the sound pressure level of 2kHz mentioned above has not been determined. In addition, from no-feeding data at night, there are also short-time 'click' signals, which are notably different from daytime's data, and sometimes is concentrated on the low-frequency (about 4kHz) from the energy of the signal. Further research is needed to determine whether there is a relationship between the two low-frequency signals.
