Sharing High Growth across Generations: Pensions and Demographic Transition in China

We analyze intergenerational redistribution in emerging economies with the aid of an overlapping generations model with endogenous labor supply. Growth is initially high but declines over time. A version of the model calibrated to China is used to analyze the welfare effects of alternative pension reforms. Although a reform of the current system is necessary to achieve financial sustainability, delaying its implementation implies large welfare gains for the (poorer) current generations, imposing only small costs on (richer) future generations. In contrast, a fully funded reform harms current generations, with small gains to future generations

Development and evaluation of the first high-throughput SNP array for common carp (Cyprinus carpio)

BACKGROUND: A large number of single nucleotide polymorphisms (SNPs) have been identified in common carp (Cyprinus carpio) but, as yet, no high-throughput genotyping platform is available for this species. C. carpio is an important aquaculture species that accounts for nearly 14% of freshwater aquaculture production worldwide. We have developed an array for C. carpio with 250,000 SNPs and evaluated its performance using samples from various strains of C. carpio. RESULTS: The SNPs used on the array were selected from two resources: the transcribed sequences from RNA-seq data of four strains of C. carpio, and the genome re-sequencing data of five strains of C. carpio. The 250,000 SNPs on the resulting array are distributed evenly across the reference C.carpio genome with an average spacing of 6.6 kb. To evaluate the SNP array, 1,072 C. carpio samples were collected and tested. Of the 250,000 SNPs on the array, 185,150 (74.06%) were found to be polymorphic sites. Genotyping accuracy was checked using genotyping data from a group of full-siblings and their parents, and over 99.8% of the qualified SNPs were found to be reliable. Analysis of the linkage disequilibrium on all samples and on three domestic C.carpio strains revealed that the latter had the longer haplotype blocks. We also evaluated our SNP array on 80 samples from eight species related to C. carpio, with from 53,526 to 71,984 polymorphic SNPs. An identity by state analysis divided all the samples into three clusters; most of the C. carpio strains formed the largest cluster. CONCLUSIONS: The Carp SNP array described here is the first high-throughput genotyping platform for C. carpio. Our evaluation of this array indicates that it will be valuable for farmed carp and for genetic and population biology studies in C. carpio and related species

N2O Fluxes and Rates of Nitrification and Denitrification at the Sediment–Water Interface in Taihu Lake, China

Because of global concerns regarding pollution and eutrophication in fresh water, China’s Taihu Lake has gained attention both for these issues and as a source of nitrous oxide (N2O) emissions. In this study, we investigated N2O fluxes and nitrification and denitrification rates at the sediment–water interface and analyzed monthly the relationships between these processes in different areas of Taihu Lake over a one-year period. Annual maximum nitrification and denitrification rate and N2O flux were observed during June in an algae-dominated area of the lake and measured 17.80, 235.51, and 31.49 µmol N m−2 h−1, respectively. The nitrification rate ranged from 0 to 1.18 µmol N m−2 h−1 at other sampling sites, with less variation. The denitrification rate showed clear seasonal variation, with lower levels between August and January (0.01–8.57 µmol N m−2 h−1; average = 1.49 µmol N m−2 h−1) and a rapid increase between February and July (1.03–235.51 µmol N m−2 h−1; average = 41.73 µmol N m−2 h−1).The N2O flux ranged from −0.64 to 1.5 µmol N m−2 h−1, with little variability except for a much higher rate (31.49 µmol N m−2 h−1) in June in algae-dominated areas. N2O flux was significantly positively correlated with nitrification and denitrification rates in most lake zones. By comparing the slopes of the regression equations, we found that N2O emissions from the sediment–water interface were influenced predominantly by nitrification, suggesting that lower N2O fluxes from the sediment–water interface in Taihu Lake are caused primarily by lower nitrification rates

Quantifying Grazing Intensity in China Using High Temporal Resolution MODIS Data

Grassland as a distinct landscape type sustains biological and cultural diversity. However, its use at an unprecedentedly high intensity has had a disastrous impact on grassland ecosystems, with degeneration occurring nationwide. Traditional management policy, drafted according to the stocking rate from livestock statistics and/or in situ assessment, seems to have played no role in alleviating this trend. A major cause is the failure of decision making to consider spatial heterogeneity in the impact of grazing on grassland. To address this issue, high temporal resolution moderate-resolution imaging spectroradiometer data were used to develop a new indicator, named the grazing intensity index (GII), for quantifying grazing intensity (GI). The new index was compared with two traditional approaches and the results demonstrated that GII could substitute for both of them to quantify GI