3 results
Improvement of soil aggregate-associated carbon sequestration capacity after 14 years of conservation tillage
- Siyu Chen, Yaqian Cao, Tingting Zhang, Jichao Cui, Liangliang Guo, Ying Shen, Pengchong Zhou, Huifang Han, Tangyuan Ning
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- Journal:
- Experimental Agriculture / Volume 58 / 2022
- Published online by Cambridge University Press:
- 28 November 2022, e55
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The North China Plain is an important summer maize/winter wheat rotation area. However, over the years, continued intensive tillage has destroyed the soil aggregate accelerating the mineralization and decomposition of soil organic carbon (SOC), which plays an important role in soil quality, as increased organic carbon storage improves soil fertility and crop yields. Thus, the objective of this study was to explore the comprehensive impact of tillage methods on soil aggregates, aggregate-associated SOC, and carbon sequestration capacity under a regime of straw return. In 2002, we started a 14-year long-term tillage experiment; then in 2016–2017, we tested the following tillage methods, zero tillage (ZT), rotary tillage (RT), subsoiling (SS), and conventional tillage (CT). The results showed that in the 0–10 cm soil layer, tillage methods significantly reduced the proportion of aggregates in the order of 2–0.25 > 5–2 > 0.25–0.053 mm. Additionally, conservation tillage (i.e., SS and ZT) significantly increased the percentage of macroaggregates (0–40 cm) and their SOC content, compared to CT. Additionally, the contribution rate of macroaggregates to SOC was 17.2% and 30.6% higher under SS and ZT than under CT, respectively. Conservation tillage methods improved the carbon sequestration capacity of soil aggregates. Our study provides a theoretical basis for the development of more suitable tillage methods. Furthermore, long-term conservation tillage seemingly protected large aggregates and, SOC, whereby carbon sequestration was enhanced and soil carbon emissions were effectively reduced.
Archaeocyathan zonation of the Yangtze Platform: Implications for regional and global correlation of lower Cambrian stages
- AIHUA YANG, MAOYAN ZHU, ANDREY YU ZHURAVLEV, KEXING YUAN, JUNMING ZHANG, YAQIAN CHEN
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- Journal:
- Geological Magazine / Volume 153 / Issue 3 / May 2016
- Published online by Cambridge University Press:
- 24 July 2015, pp. 388-409
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Detailed analysis of the distribution of archaeocyaths in five lower Cambrian sections in South China has resulted in the erection of four new archaeocyathan zones and one new archaeocyathan bed. Listed in order of ascending age, these are: the Dailycyathus xiuqiensis Zone; the Dictyocyathus shaanxiensis Zone; the Spirillicyathus duplex Range Zone; the Sibirecyathus meitanensis Range Zone; and the Archaeocyathus yanjiaoensis beds. These new subdivisions permit a correlation of lower Cambrian strata both within the area of the Yangtze Platform (South China) as well as between this region and Siberia, Australia, Western Europe and North America. Within the Yangtze Platform area, archaeocyaths of the Dailycyathus xiuqiensis and Dictyocyathus shaanxiensis zones co-occur with trilobites of the middle and upper Eoredlichia Trilobite Zone of the Qiongzhusian Stage. The Spirillicyathus duplex and the Sibirecyathus meitanensis Range Zone correspond to the Malungia, Yiliangella–Yunnanaspis and Drepanuroides Trilobite zones of the basal and middle Canglangpuan Stage, respectively. Finally, the Archaeocyathus yanjiaoensis beds belong to the Palaeolenus fengyangensis Trilobite Zone of the upper Canglangpuan Stage. Global correlations based on archaeocyath assemblage zones suggest that: (1) the middle–upper Qiongzhusian of South China correlates with the middle Atdabanian Stage of the Siberian Platform, the Warriootacyathus wilkawillinensis Archaeocyath Zone in South Australia, the middle Issendalenian Stage of Morocco and the lower Ovetian Stage in Spain; (2) the lowermost Canglangpuan Stage of South China correlates with the uppermost Atdabanian of the Siberian Platform, the Spirillicyathus tenuis – Jugalicyathus tardus archaeocyath zones in South Australia, the uppermost Issendalenian – lower Banian stages of Morocco, the middle Ovetian Stage of Spain and the middle Montezuman Stage of North America; (3) the middle Canglangpuan Stage approximates the lowermost Botoman Stage of the Siberian Platform, middle Banian Stage of Morocco, the uppermost Ovetian – lowermost Marianian stages of Spain and the upper Montezuman Stage of North America; (4) the uppermost Canglangpuan Stage is equivalent of the middle Toyonian Stage of the Siberian Platform, Archaeocyathus abacus beds in Australia, the middle Bilbilian Stage in Spain and the middle Dyeran Stage (Bolbolenellus euryparia Trilobite Zone) in North America.
A meta-analysis of re-treatment for intravenous immunoglobulin-resistant Kawasaki disease
- Xi Yang, Guiying Liu, Yaqian Huang, Stella Chen, Junbao Du, Hongfang Jin
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- Journal:
- Cardiology in the Young / Volume 25 / Issue 6 / August 2015
- Published online by Cambridge University Press:
- 19 January 2015, pp. 1182-1190
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Objective
To determine the optimal drug therapy for intravenous immunoglobulin-resistant Kawasaki disease.
MethodsStudies regarding drug therapy for intravenous immunoglobulin-resistant Kawasaki disease were selected from medical electronic databases including PubMed, Medline, Elsevier, and Springer Link. The effectiveness in terms of temperature recovery and coronary artery damage was compared between a second intravenous immunoglobulin treatment and glucocorticosteroid treatment for children with intravenous immunoglobulin-resistant Kawasaki disease using meta-analysis with Review Manager 5.3 software. Indices to evaluate the effects were body temperature, biomarker levels, and coronary artery lesions detected by echocardiography. Results are reported as relative risks or odds ratio with a 95% confidence interval and p<0.05.
ResultsMeta-analysis included 52 patients in the second intravenous immunoglobulin treatment group and 75 patients in the glucocorticosteroid treatment control group from four studies that met our inclusion criteria. Temperatures of patients who received glucocorticosteroid treatment were effectively controlled compared with those who received a second intravenous immunoglobulin treatment (relative risk=0.73, 95% confidence interval: 0.58–0.92, p=0.007). There were no differences, however, in the incidence of coronary artery lesions between the two groups (odds ratio=1.55, 95% confidence interval: 0.57–4.20, p=0.39).
ConclusionsGlucocorticosteroids are more effective in controlling body temperature compared with intravenous immunoglobulin re-treatment in intravenous immunoglobulin-resistant Kawasaki disease children; however, glucocorticosteroids and intravenous immunoglobulin re-treatment showed no difference in the prevention of coronary artery lesions.