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Soil erosion and extensive management, as key factors limiting the sustainability of the agroecosystem in the Loess Plateau, severely hamper the high-quality development of regional agriculture. Soil fertility and element synergy can be enhanced by applying mulching measures properly. However, there is a lack of systematic research into how soil stoichiometric characteristics under mulching affect crop productivity. This study focused on the agroecosystem of the Loess Plateau. Based on the 11-year field positioning experiment, the management measures of straw mulching (SM), plastic mulching (PM) and ridge-film mulching (RM) were selected to investigate the effects of long-term mulching measures on the stoichiometric characteristics of topsoil and the impact of crop productivity under the ecological stoichiometry theory. The findings revealed a significant increase in soil carbon, nitrogen and phosphorus contents and microbial biomass under mulching. SM and RM significantly decreased the stoichiometric ratio of soil available nutrients, whereas PM and RM had effective alleviating effects on C:N and C:P imbalance. The yield components of long-term SM and RM greatly increased and responded favorably to the synergy of soil carbon and phosphorus. This study provides theoretical guidance and technical support for the assessment of the effective and sustainable use of agricultural resources on the Loess Plateau. [ABSTRACT FROM AUTHOR]

In the pulsed electroacoustic (PEA) space charge measurement system used for coaxial cables, the waveform of a coupled pulse will directly affect space charge profiles in cable insulation. In this paper, on the basis of the PEA measurement system with pulse injection from a measuring electrode, the original charge acoustic signals in a 35 kV cross-linked polyethylene (XLPE) cable were collected directly from the oscilloscope under different ground distances between the measuring point and the ground point along a cable's semiconductive (SC) layer. At the same time, the effects of ground distance, cable specification, and cable length on the waveform of a coupled pulse were studied through a series of experiments and simulations. The results show that the amplitude of the coupled pulse is directly proportional to the ground distance but inversely proportional to the cable cross section or voltage class. Furthermore, the pulse coupling efficiency is almost the same only if the cables have the same diameter of the outer SC layer. Therefore, a constant pulse coupling efficiency can be obtained by adjusting the ground distance according to the diameter of the cable's outer SC layer. [ABSTRACT FROM AUTHOR]

Aim: To investigate the difference in long-term outcomes between gastric cancer patients with and without a primary symptom of overt bleeding (OB)., Methods: Consecutive patients between January 1, 2007 and March 1, 2012 were identified retrospectively by reviewing a gastric cancer database at Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine. A follow-up examination was performed on patients who underwent a radical gastrectomy. OB due to gastric cancer included hematemesis, melena or hematochezia, and gastric cancer was confirmed as the source of bleeding by endoscopy. Patients without OB were defined as cases with occult bleeding and those with other initial presentations, including epigastric pain, weakness, weight loss and obstruction. The 3-year overall survival (OS) rate, age, gender, AJCC T stage, AJCC N stage, overall AJCC stage, tumor size, histological type, macroscopic (Borrmann) type, lymphovascular invasion and R status were compared between patients with and without OB. Moreover, we carried out a subgroup analysis based on tumor location (upper, middle and lower)., Results: We identified 939 patients. Of these, 695 (74.0%) were hospitalized for potential radical gastrectomy and another 244 received palliative resection, rerouting of the gastrointestinal tract, chemotherapy, radiotherapy or no treatment due to the presence of unresectable tumors. Notably, there was no significant difference in the percentage of OB patients between resectable cases and unresectable cases (20.3% vs 22.1%, P = 0.541). Follow-up examination was performed on 653 patients (94%) who underwent radical gastrectomy. We found no significant difference in 3-year OS rate (68.2% vs 61.2%, P = 0.143) or clinicopathological characteristics (P > 0.05) between these patients with and without OB. Subgroup analysis based on tumor location showed that the 3-year OS rate of upper gastric cancer was significantly higher in patients with OB (84.6%) than in those without OB (48.1%, P < 0.01) and that AJCC stages I-II (56.4% vs 35.1%, P = 0.017) and T1-T2 category tumors (30.8% vs 13%, P = 0.010) were more frequent in patients with OB than in those without OB. There was no significant difference in 3-year OS rate or clinicopathological characteristics between patients with and without OB (P > 0.05) for middle or lower gastric cancer., Conclusion: Upper gastric cancer patients with OB exhibited tumors at less advanced pathological stages and had a better prognosis than upper gastric cancer patients without OB.