RESUMO
Large-scale measurements of soil moisture play a critical role in many fields, such as agriculture, hydrology, and engineering. The distributed temperature sensing (DTS) technology, based on a dual-probe heat pulse (DPHP), is a novel approach to realizing large-scale soil moisture estimation. However, the application of the method is limited by the complex optical cable layout, calculation algorithm, and lack of standardized heating strategy. In this paper, an improved DPHP-DTS method considering the soil bulk density was proposed. The measurement accuracy of the DPHP-DTS method under different heating strategies was studied in laboratory experiments, and its long-term stability in regard to the monitoring of soil moisture during natural evaporation in different soils was tested. The results show that the improved DPHP-DTS method can accurately measure the soil moisture, and the fitting algorithm can reduce the error caused by the accuracy of the DTS temperature measurement under the low-power heating strategy. Its measurement accuracy increases with the increase in the heating strength and duration. In addition, the improved DPHP-DTS method can describe soil evaporation in both sand and loess with good reliability and stability.
RESUMO
OBJECTIVE: To evaluate the effectiveness and safety of microsurgical gonadal-inferior epigastric vein anastomosis for the treatment of the nutcracker phenomenon (NCP) associated with left gonadal vein varices with reflux. METHODS: Thirty-five patients with NCP associated with left gonadal vein varices with reflux diagnosed in our hospital from June 2016 to June 2018 were included. All patients underwent a shunt operation consisting of microsurgical gonadal-inferior epigastric vein anastomosis, and the patients were followed up for 1 year. RESULTS: All patients were successfully operated on, with an average operation time of 96.5 ± 12.3 min. After a 1-year follow-up, the symptom of gross hematuria disappeared in 3 patients (including 1 woman). For the other 32 patients, the sperm concentration (27.43 ± 8.68 × 106/ml) and motility (33.06 ± 4.27%) postoperatively were significantly higher than that preoperatively (16.21 ± 6.43 × 106/ml and 23.48 ± 4.43%, respectively) (P < 0.05); among these patients, 2 had natural pregnancies with their spouses. The peak velocity (PV) at the aortomesenteric portion of the left renal vein (LRV) and the PV ratio between the aortomesenteric and hilar portion of the LRV significantly decreased after surgery (117.9 ± 30.4 cm/s vs 76.6 ± 18.5 cm/s; 7.3 ± 0.7 vs 4.1 ± 0.4). Two patients had complications of mild hydroceles requiring no intervention, and no major complications were observed during and after surgery. CONCLUSION: Our results suggest that the microsurgical gonadal-inferior epigastric vein anastomosis is both effective and safe to treat patients with gonadal varicose veins caused by the nutcracker phenomenon.