The shoot tip explants of the tillered onion line Z-018 were used as experimental materials. The effects of colchicine and pendimethalin on the induction of polyploid tillered onion were studied in vitro with different concentrations and treatment time. Treatment with 250 μmol/L colchicine for 4 days caused a variant rate of 42.22% and a mortality rate of 36.67%, whereas treatment with 30 μmol/L pendimethalin for 6 days caused a variant rate of 41.11% and a mortality rate of 24.44%. Subsequent cytological identification showed that tetraploid plants were successfully induced by both mutagens. Compared with the diploid plants, the tetraploid plants exhibited slower growth, thicker leaves, stems and roots, larger stomatal apparatus and increased number of chloroplasts. In addition, the obtained tetraploid plants have thicker tubular leaves, decreased number of tillers, larger bulbs and increased yield of the products. This provides the basis for future research on tillered onion germplasm resources.

This paper proposes a new planar inductive sensor with printed circuit boards (PCB) based stator and rotor, which can perform more precision measurement than traditional inductive angular displacement sensors. The sensor uses PCB technique to realize accurately configured planar coils. The stator consists of a ferromagnetic base plate and a PCB with three groups of circular excitation coils and two groups of sine shape pickup coils working as two sense channels. The rotor consists of a ferromagnetic base plate and a PCB with two circles of copper pieces. Copper pieces on the rotor PCB produce eddy current in the time-varying magnetic field and alter the outputs of two sense channels of pickup coils cyclically with the rotor's rotation. Two fine sense channels can make incremental angle measurement individually and work together to make absolute angle measurement. A prototype with 63 and 64 period sense channels was designed and developed for experiments, and test results show that it was finally examined with short-period error of 14.7" and full range error of 20.6". The possessed characteristics of inductive principle, absolute measuring and good accuracy make this type of sensor is very suitable for high precision, reliable measurement in harsh environments.

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This article studies cost‐plus‐time (A+B) procurement contracting with time incentives in the highway construction industry. In the presence of construction uncertainty, the contractor's actual completion time may deviate from the bid completion time, and the A+B contract design is not ex post efficient. Using data from highway procurement contracts in California, we show that an ex post efficient lane rental contract would reduce the social cost by $41.39 million (43.11%) on average. Moreover, the average commuter cost would decrease by $62.06 million (78.96%), suggesting a substantial reduction in the construction externality to commuters from lane rental contracts.

Tomato as a fresh fruit has a large market share in China, but few new materials have been developed for such cultivar breeding in recent years. This study aims to create innovative breeding materials for fresh fruit tomatoes with consistent genetic backgrounds and take advantage of beneficial genes from wild germplasm resources. An introgression line (IL) population was constructed using freshly cultivated tomato S. lycopersicum 1052 and wild tomato S. pennellii LA0716 through hybridization and five consecutive backcrossings, with molecular marker-assisted selection techniques during seedling stages. A total of 447 cleaved amplified polymorphic sequences (CAPS) and 525 simple sequence repeat (SSR) markers were used to screen polymorphic markers among the two parental lines, resulting in 216 polymorphic CAPS and 236 polymorphic SSR markers, with 46.5% parental polymorphism. Then, 200 molecular markers uniformly distributed over the entire genome were further selected, and 107 ILs were finally obtained from 541 BC5 candidate plants. The physical distance between adjacent markers was 6.3~10.0 cm, with an average interval of 7.29 cm, and the IL population constructed covered the whole genome of S. pennillii LA0716, with an average introgression segment of 31.5 cm. Moreover, phenotype data of major agronomic traits in BC5 progeny after selfing two times, were analyzed for quantitative trait locus (QTL) mapping, and a total of 11 QTLs distributed on 6 chromosomes were identified, including 3 QTLs regulating plant height, 1 QTL regulating leaf size, 1 QTL regulating fruit color, 4 QTLs regulating fruit weight, and 2 QTLs regulating soluble solids content in ripening fruits. The IL population constructed in this study provided good materials for fresh fruit tomato breeding with improved yield and quality in the future.