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Arising of disasters by climate change had affected crop growth and yield, and then threaten local to global food security, particularly heat stress. Therefore, hazard assessment is essential to develop effective disaster risk management and adaptation interventions to ensure food security. In this study, the accumulated heat stress days (DAY), heat stress intensity (HSI) and heat degree-days (HDD) during the post-silking period of summer maize in The Huang-Huai-Hai Plain were investigated. Based on the optimal probability distribution function of HDD and information diffusion theory, we compute heat stress classification index and the possibility of heat stress, respectively. During 1981–2019, DAY, HSI and HDD were 11.8 d, 31.9°C and 23.6°Cd and increased by 0.67 d/decade, 0.10°C/decade and 3.14°Cd/decade, respectively. The threshold and hazard probability of mild, moderate and severe heat stress were 9.4, 19.4 and 34.2°Cd and 16.6, 9.3 and 4.5%, respectively. The heat stress hazard index (M) was 0.48, ranged from 0 to 0.77 during 1981 to 2019. M will increase in the future at all regions, particularly after 2060. Under SSP5-8.5 climate scenario, M ranged from 0.95 to 1.20 in 2080s, about two times than historical period. This could be used in optimizing agricultural management in summer maize production in order to combat heat stress under projected climate change. [ABSTRACT FROM AUTHOR]

Understanding climate change and extreme climate is of great significance for ensuring food security and socio-economic development of the Songhua River Basin. Based on the daily precipitation, maximum temperature and minimum temperature data during 1961-2020 from 69 meteorological stations in and around the Songhua River Basin, we analyzed the temporal and spatial variations of extreme temperature and precipitation in the Songhua River Basin using 27 extreme climate indices recommended by the World Meteorological Organization, and linear trend method, Mann-Kendall trend test and ordinary Kriging interpolation methodology. The results showed that, from 1961 to 2020, except for cold speel duration, the extreme cold index in the study area showed a downward trend, while the extreme warm index, extreme value index and other temperature indices showed an upward trend. The increasing trend of the minimum temperature was greater than that of the maximum temperature. Icing days, cold speel duration and warm speel duration showed an increasing trend from south to north, while the minimum value of maximum temperature and that of minimum temperature showed opposite spatial characteristics. The high value areas of summer days and tropical nights were mainly distributed in the southwestern region, while there was no obvious spatial variations of cool days, warm nights, and warm days. Overall, except for cold speel duration, other extreme cold indices had a rapid decreasing trend in the north and west of the Songhua River Basin. In the warm index, summer days, warm nights, warm days, and warm speel duration had a rapid upward trend in the north and west, and tropical nights had the fastest rise in the southwest. In the extreme value index, the maximum of temperature rose fastest in the northwest, while the minimum rose fastest in the northeast. Except for consecutive dry days, the rest of precipitation indices showed an increasing trend, and the fastest rising areas were mainly in the north-central part of the Nenjiang River Basin, while some areas in the south of the Nenjiang River Basin became dry. Heavy precipitation days, very heavy precipitation days, heaviest precipitation days, consecutive wet days, very wet day precipitation, extremely wet day precipitation, and annual precipitation showed a gradual decreasing pattern from southeast to northwest. Overall, the Songhua River Basin was warming and wetting, but there were some differences among different regions, especially the northern and southern parts of the Nenjiang River Basin. [ABSTRACT FROM AUTHOR]

IrO2 exhibits good stability but limited electrocatalytic activity for oxygen evolution reaction in acid. Defect engineering is an effective strategy to improve the intrinsic ability of electrocatalysts by tailoring their electronic structure. Herein, we have successfully synthesized IrO2/Ir heterophase with compressive strain and metal vacancies via a simple substitution-etching method. In virtue of the solubility of Cr in strong alkali, metal vacancies could be formed at surface after etching Cr-doped IrO2/Ir in alkali, which leaded to modulated electronic structure. Meanwhile, the substitution of Cr with smaller atom radius would induce the formation of compressive strain and the relocated atoms made the d-band center shifted. With the regulated electronic structure and tuned d-band center, the obtained electrocatalyst only needed 285 mV to reach 10 mA·cm−2 in 0.1 M HClO4. Reaction kinetic has been rapidly accelerated as indicated by the smaller Tafel slope and charge transfer resistance. Theoretical calculations revealed that the d-band center and charge density distribution have been regulated with the introduction of defects in IrO2/Ir, which significantly decreased the free energy barrier of rate determining step. This work provides a valuable reference to design effective and defects-rich electrocatalysts. [ABSTRACT FROM AUTHOR]

Objectives: Diagnosis of thyroid disease among individuals dwelling at high altitude remains a challenge. Reference intervals (RIs) for thyroid-associated hormones among Tibetans living at various high altitudes were established to improve diagnosis. Methods: One thousand two hundred eighty-one subjects were randomly recruited from Nyingchi, Shigatse/Lhasa, and Ali of Tibet. Thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) were measured by the Cobas e601 electrochemiluminescence analyzer. We used multiple linear regression and variance component analysis to assess the effect of sex, age, and altitude on hormones. RIs were established by refineR algorithm and compared with those provided by the manufacturer. Results: Serum TSH was significantly lower in males than in females, while FT3 and FT4 were higher in males. Both FT3 and FT4 decreased with increasing age. FT3 increased with altitude, while TSH and FT4 were less influenced by altitude. The RI for TSH was 0.764–5.784 μIU/ml, while for FT4, the RIs were 12.36–19.38 pmol/L in females and 14.84–20.18 pmol/L in males. The RIs for FT3 at Nyingchi, Shigatse/Lhasa, and Ali in females were 4.09–4.98, 4.31–5.45, and 4.82–5.58 pmol/L, while in males, the values were 4.82–5.41, 4.88–5.95, and 5.26–6.06 pmol/L, respectively. The obtained RIs for TSH and FT4 were generally higher, while that for FT3 was narrower than the RIs provided by Cobas. Conclusions: Specific RIs were established for thyroid-associated hormones among Tibetans, which were significantly different from those provided by the manufacturer. [ABSTRACT FROM AUTHOR]

Food security is an important guarantee of national security. The northeast black soil region is an important commodity grain production base in China, which plays a fundamental role in ensuring national food security. However, the highly intensive, unreasonable or excessive use of cultivated land in this region has caused serious black soil degradation. Therefore, how to make the Black Soil Granary to provide efficient and sustainable guarantee for national food security is a scientific problem requiring urgent solutions. This paper systematically illuminates the agricultural development of high-productivity black soils since the reform and opening-up. On this basis, the paper systematically summarizes the problems facing the sustainable development of grain production in the black soil region. Furthermore, to meet the requirements of the central government for agricultural production in Northeast China, it puts forward the corresponding countermeasures to coordinate food security and ecological security and to enhance the sustainable development of grain production, intending to provide reference for the sustainable agricultural development in the northeast black soil region, and offer scientific guidance for the strategic planning of national food industry strategy, agricultural policy making, and strengthening of national food security. [ABSTRACT FROM AUTHOR]