The impacts of conservation agriculture on crop yield in China depend on specific practices, crops and cropping regions

For smooth and wide application of conservation agriculture(CA), remaining uncertainties about its impacts on crop yield need to be reduced. Based on previous field experiments in China, a meta-analysis was performed to quantify the actual impacts of CA practices(NT: no/reduced-tillage only, CTSR: conventional tillage with straw retention, NTSR: NT with straw retention) on crop yields as compared to conventional tillage without straw retention(CT).Although CA practices increased crop yield by 4.6% on average, there were large variations in their impacts. For each CA practice, CTSR and NTSR significantly increased crop yield by 4.9%and 6.3%, respectively, compared to CT. However, no significant effect was found for NT. Among ecological areas, significant positive effects of CA practices were found in areas with an annual precipitation below 600 mm. Similar effects were found in areas with annual mean air temperature above 5 °C. For cropping regions, CA increased crop yield by 6.4% and 5.5%compared to CT in Northwest and South China, respectively, whereas no significant effects were found in the North China and Northeast China regions. Among crops, the positive effects of CA practices were significantly higher in maize(7.5%) and rice(4.1%) than in wheat(2.9%). NT likely decreased wheat yield. Our results indicate that there are great differences in the impacts of CA practices on crop yield, owing to regional variation in climate and crop types. CA will most likely increase maize yield but reduce wheat yield. It is strongly recommended to apply CA with crop straw retention in maize cropping areas and seasons with a warm and dry climate pattern.

Impact of the Pneumococcal Heptavalent Conjugated Vaccine on <i>Streptococcus pneumoniae</i>Nasopharyngeal Carriage and Antimicrobial Susceptibility in Children 2-5-Year-Old in Beijing, China

Streptococcus pneumoniae is a primary cause of illness and death among children younger than 5 years in China. The heptavalent pneumococcal conjugate vaccine (PCV7) was the only conjugated vaccine (PCV) available in China from 2008 to 2013. This randomized, controlled, open-label study conducted at 46 Beijing clinics involved 3281 healthy 2-5-year-old Chinese children, randomized 1:1 to receive one dose of the S. pneumoniae heptavalent conjugated vaccine (PCV7) (n = 1643) or Haemophilus influenzae type b conjugate vaccine (Hib) (n = 1638). The main objective of this study was to investigate the impact of PCV7 against that of Hib vaccination in the nasopharyngeal S. pneumoniae colonization in healthy Chinese children. Nasopharyngeal (NP) samples for culture, serotyping and antimicrobial susceptibility testing were collected before vaccination and at Day 60 and 180 post-vaccination. A total 3281 children were enrolled in the study. Demographic characteristics were similar among both study groups: 1641 children received PCV7. Before immunization, S. pneumoniae was isolated in 338 and 360 children in the PCV7 (144 PCV7 isolates) and Hib groups (145 PCV7 isolates), respectively. At Day 180, PCV7 vaccination was more effective than Hib vaccination in reduction NP carriage (20.2% [P = 0.052]) and new acquisition (19.0% [P = 0.066]). When reductions in NP carriage and new acquisition of PCV7 VT plus 6A was analyzed, reduction in the PCV7 vaccinated group achieved statistical significance (P = 0.034 and P = 0.042 versus Hib, respectively). NP carriage of NVT increased in both groups (P = 0.305 between study groups at Day 180). PCV7 decreased NP carriage of non-susceptible VT to amoxicillin (P = 0.000), ceftriaxone (P = 0.047) and MDR (P = 0.024) versus Hib. PCV7 vaccination in Chinese children 2 to 5 years of age was more effective than vaccination with Hib in the reduction of S. pneumoniae nasopharyngeal carriage, new acquisition and non-susceptible isolates.

China's contribution to the millennium development goals: achieving tuberculosis control targets ahead of deadline

The millennium development goals (MDGs) were eight international development targets for the year 2015 that were established following the adoption of the United Nations Millennium Declaration in 2000.The MDGs are aimed at reducing extreme poverty and set a series of time-bound goals,particularly in health,gender equality,and environmental sustainability [1].The target set for tuberculosis (TB) was to reduce TB prevalence and mortality rates by half by 2015 compared to the 1990 baseline rates [2].China has in fact achieved the TB targets five years ahead of the scheduled timeline [3].From 1990 through 2010,TB case detections had decreased by 65%,from 170 to 59 cases per 100000 population and the mortality rates by almost 80% [4].

Cap-seq reveals complicated miRNA transcriptional mechanisms in C. elegans and mouse

Background： MicroRNAs （miRNAs） regulate target gene expression at post-transcriptional level. Intense research has been conducted for miRNA identification and the target finding. However, much less is known about the transcriptional regulation of miRNA genes themselves. Recently, a special group of pre-miRNAs that are produced directly by transcription without Drosha processing were validated in mouse, indicating the complexity of miRNA biogenesis. Methods： In this work, we detect clusters of aligned Cap-seq reads to find the transcription start sites （TSSs） for intergenic miRNAs and study their transcriptional regulation in Caenorhabditis elegans and mouse. Results： In both species, we have identified a class of special pre-miRNAs whose 5＇ ends are capped, and are most probably generated directly by transcription. Furthermore, we distinguished another class of special pre-miRNAs that are 5＇-capped but are also part of longer primary miRNAs, suggesting they may have more than one transcription mechanism. We detected multiple cap reads peaks within miRNA clusters in C. elegans. We surmised that the miRNAs in a cluster may either be transcribed independently or be re-capped during the microprocessor cleavage process. We also observed that H3K4me3 and Pol II are enriched at those identified miRNA TSSs. Conclusions： The Cap-seq datasets enabled us to annotate the primary TSSs for miRNA genes with high resolution. Special class of 5＇-capped pre-miRNAs have been identified in both C. elegans and mouse. The capping patter of miRNAs in a cluster indicate that clustered miRNA transcripts probably undergo a re-capping procedure during the microprocessor cleavage process.