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At present, K-band Doppler radar has been proposed for detecting the motion state of atmospheric turbulence and obtaining wind velocity and direction. However, the echo signal of the turbulence is often interfered with strong noise, and there are multiple spectral peaks in the power spectrum, which greatly affect the overall detection accuracy of the radar. Traditional wind profile estimation methods directly analyze the coherent accumulation (CA) signal using a cost function, which is susceptible to clutter and noise during the selection of the candidate spectral peaks. To overcome the shortcomings of traditional methods under the condition of low signal-to-noise ratio (SNR) and multiple peaks, in this article, we propose a novel method based on the mutual convolution cost function (MCCF), which utilizes the mutual convolution and the complex least mean square (MCLMS) method to filter the CA signal, and then generates a cost function to select the optimal spectral peaks in the space-time Doppler window. This systematically solves the problem of turbulence echoes being interfered with strong noise and multiple peaks. Finally, the commonly used methods are compared with the proposed method, and the statistical results of these methods are verified by using LIDAR data. The results indicate that the proposed method can improve the SNR by 2–4 dB and improve the overall correlation coefficient (CC) by about 10% of the radar.

Four experiments were performed to investigate the role of the mitogen-activated protein kinase (MAPK) signaling pathway in intestinal absorption of phosphorus (P) and calcium (Ca) in broiler chickens. Experiment 1 assessed how dietary levels of 1,25-dihydroxyvitamin D3(1,25(OH)2D3) influence the gene expression of intestinal P and Ca transporters in broilers. Experiment 2 evaluated the effects of 1,25(OH)2D3administered via intraperitoneal injection on the extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (p38MAPK) signaling pathways. Experiments 3 and 4 investigated the effect of ERK and p38MAPK inhibitors on the expression of intestinal P and Ca transporters. The findings demonstrated that broilers (1–21 days old) fed a 1,25(OH)2D3-deficient diet (0.625 µg/kg) exhibited reduced body weight, tibia P and Ca levels, and mRNA levels of P transporters (NaPi-IIb, PiT-1, and PiT-2), Ca transporters (NCX1, PMCA1b, and CaBP-D28k), vitamin D receptors (VDR), ERK, and p38MAPK in the duodenum (Experiment 1) (P< 0.05). By comparison, the growth, bone quality, and mRNA levels of genes (except for duodenal NaPi-IIb) in broilers were similar to those in broilers fed the control diet when dietary 1,25(OH)2D3was adequate (5 µg/kg) (Experiment 1) (P> 0.05). After intraperitoneal injection of 1,25(OH)2D3, the mRNA level of jejunal NaPi-IIb and the protein level of p-p38MAPK/t-p38MAPK in broilers (9–14 days old) decreased (P< 0.05), whereas the mRNA level of CaBP-D28k and the protein level of p-ERK/t-ERK increased (Experiment 2) (P< 0.05). The mRNA and protein expression of jejunal NaPi-IIb and the protein expression of CaBP-D28k in broilers (9–17 days old) treated with the ERK inhibitor PD98059 were greater than those in the control group (Experiment 3) (P< 0.05). Similarly, compared with control broilers, broilers (9–17 days old) treated with the p38MAPK inhibitor SB203580 showed elevated mRNA expression of jejunal NaPi-IIb and CaBP-D28k (Experiment 4) (P< 0.05). These results suggest that adequate supplementation with 1,25(OH)2D3(5 µg/kg) can restore broiler growth and bone quality by upregulating the transcription of genes involved in intestinal P and Ca absorption. Additionally, the ERK and p38MAPK signaling pathways are implicated in the modulatory effect of 1,25(OH)2D3on the absorption of P and Ca in broilers.