The18 Ne(α,p) 21 Na reaction is thought to be one of the key breakout reactions from the hot CNO cycles to the rp-process in type I x-ray bursts. In this work, the resonant properties of the compound nucleus 22 Mg have been investigated by measuring the resonant elastic scattering of 21 Na+p. An 89 MeV 21 Na radioactive beam delivered from the CNS Radioactive Ion Beam Separator bombarded an 8.8 mg/cm 2 thick polyethylene (CH2)n target. The 21 Na beam intensity was about 2×10 5 pps, with a purity of about 70% on target. The recoiled protons were measured at the center-of-mass scattering angles of θc.m.≈175.2• , 152.2 • , and 150.5• by three sets of ∆E-E telescopes, respectively. The excitation function was obtained with the thick-target method over energies Ex( 22 Mg)=5.5-9.2 MeV. In total, 23 states above the proton-threshold in 22 Mg were observed, and their resonant parameters were determined via an R-matrix analysis of the excitation functions. We have made several new J π assignments and confirmed some tentative assignments made in previous work. The thermonuclear 18 Ne(α,p) 21 Na rate has been recalculated based on our recommended spin-parity assignments. The astrophysical impact of our new rate has been investigated through one-zone postprocessing x-ray burst calculations. We find that the 18 Ne(α,p) 21 Na rate significantly affects the peak nuclear energy generation rate, reaction fluxes, as well as the onset temperature of this breakout reaction in these astrophysical phenomena.

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Intensive vegetable cultivation has developed very rapidly in China, and investigation of current soil nutrient problems in vegetable fields and their potential environmental risk is important for local soil nutrient management strategies. Three hundred and sixty-six soil samples were collected from greenhouse vegetable fields, open vegetable fields and rice/wheat rotation fields in southern Jiangsu Province, the most intensive vegetable-producing areas in Yangtze River Delta, China, for the analysis of their soil fertility status. Soil acidification and P enrichment were the main problems identified in this area of vegetable production, with about 20 and 17% of the open and greenhouse vegetable field soils, respectively, being extremely acid with soil pH values below 5.0. In contrast, no soils under rice/wheat rotation fields were as acidic. Percentages of sites with Olsen-P concentrations < 90 mg/kg were 61, 85 and 0% for soils growing greenhouse vegetable, field vegetable and rice/ wheat, respectively. The nitrogen (N) surplus for vegetable fields exceeded 170 kg/ha/crop, and the phosphorus (P) surplus exceeded 40 kg/ha/crop. Thus, current vegetable production leads to potential environmental risks of N and P pollution of nearby aquatic bodies. Insufficient supplementation with potassium fertilizers was found in some vegetable fields. Several ameliorative measures are proposed.