Do Rural-Urban Identities Affect Individuals' Health? Evidence From China.

We study the relationship between household registration status (Hukou) and the state of individuals' health to find out whether inequality in health between urban and rural population exists in China. We have used the probit model to regress the state of health on household registration using the individual-level data of the 2018 CFPS survey. We find that inequality in health between urban and rural population does exist in China. Individuals with rural Hukou have a higher probability by 1.4% to be admitted to hospital than individuals with urban Hukou. While, individuals with rural Hukou tend to over-estimate the state of their health as the probability for them to assess themselves healthy is higher by 1.7% than individuals with urban Hukou. The findings suggest that policy makers should recognize the issue of rural-urban health inequalities and take measures, such as controlling pollution in rural areas and providing high quality routine health checks for rural population to deal with the problem.

[Soil stoichiometry characteristics under different land use types in the Horqin Sandy Land, China]. / 科尔沁沙地不同土地利用类型土壤化学计量特征.

The stoichiometry characteristics of carbon (C), nitrogen (N), and phosphorus (P) is an important indicator of soil quality and ecosystem nutrient limitations. Exploring the effects of land use type and soil depth on soil nutrient stoichiometry can clarify soil nutrient cycling. In this study, we collected soil samples from sites with five different land use types (irrigated cropland, rainfed cropland, sandy grassland, fixed dunes, and mobile dunes) in the Horqin Sandy Land, and evaluated the influences of land use type and soil depth on the contents and stoichiometry characteristics of soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP). We found that: 1) SOC (3.23 g·kg-1), TN (0.37 g·kg-1), and TP (0.15 g·kg-1) contents and stoichiometry characteristics (C:N, C:P, N:P was 9.07, 25.56, 2.97, respectively) to a depth of 10 cm in the Horqin Sandy Land were significantly lower than the mean values of soils in China. 2) Soil stoichiometry characteristics differed significantly among land use types. The contents of SOC, TN, and TP to a depth of 100 cm were highest in irrigated cropland, followed by sandy grassland, rainfed cropland, fixed dunes, and mobile dunes. The C:N ratios in sandy grassland, irrigated cropland, and rainfed cropland were significantly higher than those in the fixed dune and mobile dune sites. C:P ratios in the sandy grassland, fixed dunes, irrigated cropland, and rainfed cropland were significantly higher than that in the mobile dunes. The N:P ratio differed little among the five land use types. 3) SOC and TN contents in the sandy grassland, fixed dunes, irrigated cropland, and rainfed cropland decreased with increasing soil depth. SOC, TN, and C:P in the mobile dunes and TP and C:N in all land use types showed no variation among depths. The C:P ratio of sandy grassland, fixed dunes, irrigated cropland, and rainfed cropland and the N:P ratio of sandy grassland decreased with increasing soil depth. 4) SOC, TN, and TP contents and the C:N ratio were significantly negatively correlated with the contents of medium and fine sands and with soil bulk density, but significantly positively correlated with silt+clay, and very fine sand contents. Desertification led to losses of SOC and nutrients in the Horqin Sandy Land, and exacerbated soil N deficiency. Inputs of water and ferti-lizer helped cropland to maintain a relatively high level of soil nutrients.

[Soil amelioration of different vegetation types in saline-alkali land of the Yellow River Delta, China]. / 黄河三角洲盐碱地不同植被模式的土壤改良效应.

Yellow River Delta is an important distribution area of coastal saline-alkali land in China. Revegetation is the main technology for ecological restoration during saline-alkali land amelioration. To explore the effects of different vegetation types on soil improvement in saline-alkali land and get the suitable model in the Yellow River Delta, four tree-grass compound models, Salix americana+Distichlis spicata, S. matsudana+D. spicata, Tamarix chinensis+Medicago sativa, and Fraxinus chinensis+T. chinensis+M. sativa, were set up, with pure S. americana forest as the control. Twenty indicators, including soil moisture physical parameters, saline-alkali content, soil nutrient contents, and microorganism quantity etc. were measured. Principal component analysis, cluster analysis and fuzzy mathematics were used to evaluate soil modification effect of different vegetation combinations. The results showed that all compound models significantly improved soil physical and che-mical properties in coastal saline-alkali land by increasing soil porosity, soil water storage, soil organic matter content, available nutrient content and soil microorganism quantity and reducing soil density. Among all the models, the tree-shrub-grass mixed model of F. chinensis+T. chinensis+M. sativa was the most effective in inhibiting salt and alkali stress and increasing soil nutrients and microorganism abundance, whereas the tree-grass mixed model of S. matsudana+D. spicata was the most effective in improving soil water physical properties. The combined effects of different vegetation patterns on soil amelioration in coastal saline-alkali land of the Yellow River Delta were arranged in order of F. chinensis+T. chinensis+M. sativa> S. matsudana+D. spicata> S. americana+D. spicata> T. chinensis+M. sativa.

[Effects of multiple times of topdressing nitrogen application under equal level on utilization and distribution characteristics of 15N and 13C in winter jujube]. / 等量分次施氮对冬枣15N和13Cåˆ©ç”¨ä¸Žåˆ†é ç‰¹æ€§çš„å½±å“.

We explored the effects of multiple times of topdressing nitrogen application under equal level on the characteristics of absorption, utilization, accumulation, and distribution of 15N and 13C in four-year-old potted winter jujube during fruit developmental periods using the stable isotope tra-cer technology. The results showed that with the increases of nitrogen application times, the 15N derived from fertilizer (Ndff) in each organ significantly increased at the fruit maturity. The distribution rates of 15N in reproductive organ (fruit) and vegetative organs (leaf, deciduous spur, new branch, and fine root) were highest under four-time application, and lowest under one-time application. The opposite pattern was observed in storage organs (trunk, perennial branch, and coarse root). The 15N utilization rate under four-time application was 27.4% and 15.5% higher than one-time and two-time application, respectively. The more times N being applied, the more total N content and 15N absorption amount of plant. Soil 15N abundance and total N content continued to drop under one-time application and increased at the beginning and then declined with the time under two-time application. The relatively stable soil 15N abundance and total N content appeared in four-time application, which was significantly higher than those in the other treatments in later treatment stages. The chlorophyll content, leaf nitrogen content and photosynthetic rate displayed an order of four-time application > two-time application > one-time application during fruit white-mature period to fruit harvest period. The accumulation and distribution of 13C varied across different treatments. Increasing nitrogen application times would promote more 13C being transported to fruit and storage organs but decrease that in annual vegetative organs. Our findings indicated that four-time nitrogen application could enhance and optimize the accumulation and distribution of photosynthetic products by ensuring steady and adequate supply of nitrogen and improving the absorption and utilization of nitrogen during fruit development period, which facilitates the growth, yield and quality of winter jujube.

Activation of GLP-1 Receptor Enhances Neuronal Base Excision Repair via PI3K-AKT-Induced Expression of Apurinic/Apyrimidinic Endonuclease 1.

Glucagon-like peptide-1 (GLP-1) is an intestinal-secreted incretin that increases cellular glucose up-take to decrease blood sugar. Recent studies, however, suggest that the function of GLP-1 is not only to decrease blood sugar, but also acts as a neurotrophic factor that plays a role in neuronal survival, neurite outgrowth, and protects synaptic plasticity and memory formation from effects of ß-amyloid. Oxidative DNA damage occurs during normal neuron-activity and in many neurological diseases. Our study describes how GLP-1 affected the ability of neurons to ameliorate oxidative DNA damage. We show that activation of GLP-1 receptor (GLP-1R) protect cortical neurons from menadione induced oxidative DNA damage via a signaling pathway involving enhanced DNA repair. GLP-1 stimulates DNA repair by activating the cyclic AMP response element binding protein (CREB) which, consequently, induces the expression of apurinic/apyrimidinic endonuclease 1 (APE1), a key enzyme in the base excision DNA repair (BER) pathway. In this study, APE1 expression was down-regulated as a consequence phosphatidylinositol-3 kinase (PI3K) suppression by the inhibitor LY294002, but not by the suppression of MEK activity. Ischemic stroke is typically caused by overwhelming oxidative-stress in brain cells. Administration of exentin-4, an analogue of GLP-1, efficiently enhanced DNA repair in brain cells of ischemic stroke rats. Our study suggests that a new function of GLP-1 is to elevate DNA repair by inducing the expression of the DNA repair protein APE1.

[Response of active nitrogen to salinity in a soil from the Yellow River Delta].

Soil salinity can inhibit the processes of nitrogen cycle, and the active nitrogen is the important indicator to reflect the turnover of nitrogen. A laboratory experiment was conducted to study the effect of soil salinity on the active nitrogen in a soil of the Yellow River Delta incubated aerobically under 25 degrees C for 45 days. Four levels of salinity (S1: 0.1%, S2: 0.5%, S3: 0.9%, S4: 1.3%) were imposed using NaCl (mass fraction), and glucose with or without NH4Cl were added to the soils. NO3(-) -N, NH4(+) -N, total soluble nitrogen (TSN) and microbial biomass nitrogen (MBN) were monitored. Results showed that NO3(-)-N was significantly higher in the low salinity soil (S1, S2) than in the high salinity soil (S3, S4) under the control and with NH4Cl addition, and especially the difference was larger with NH4Cl addition. Comparing with the control, NO3(-) -N was increased significantly in S1 and S2. NO3(-) -N was decreased significantly with glucose addition, and there was no difference among the four salinity soils during the whole incubation period. NH4(+) -N was significantly higher in the high salinity soil (S3, S4) than in the low salinity soil (S1, S2), and it was increased particularly in S4 after day 5. With the addition of NH4Cl, NH4(+) -N was increased in S3 and S4. MBN was higher in the low salinity soil than in the high salinity soil, and it was not increased with NH4Cl addition, though TSN was increased. With glucose addition, MBN was increased by 89.9% - 130.9% in the low salinity soil (S1, S2) and 36.9% - 79.5% in the high salinity soil (S3, S4). It was suggested that soil salinity had influence on N transformation, and high salinity inhibited the transformation and assimilation of N by microorganism. The addition of C depressed the effect of salinity, and improved the microbial activity. The application of organic matter is an effective measure to improve N transformation in saline soils.

[Germination and seedling growth of Artemisia halodendron under different incubation environments].

Artemisia halodendron is a dominant species in mobile and semi-mobile dunes of Horqin Sand Land. To investigate the germination character and seedling growth under different temperature and light conditions, the germination rate, germination index and growth of radicle and plumule were measured after treatments in laboratory and heating cabinet incubations. In the laboratory the light and temperature were near to nature condition, while in the heating cabinet it was kept at 25 degrees C with varying durations of light supply, including 24-, 12- and 0-hour light per day. Germination rate (66.6%) and germination index (19.1%) under laboratory condition were both significantly lower than in the heating cabinet (P < 0.05). In the heating cabinet, the germination rate under 0-hour light was 70.2%, which was insignificantly lower (P > 0.05) than under 12- and 24-hour light conditions (both 73.4%), and the germination index under 24-hour light was 28.2%, which was significantly (P < 0.05) lower than under 0- and 12-hour light conditions (31.3% and 30.8%, respectively). Radicle and plumule growth responded to light more readily than the seed germination rate and germination index during the process of germination, and the radicle growth was inhibited by darkness while promoted by light, and the plumule lengths under 0- and 12-hour light conditions were 2.81 cm and 1.51 cm, respectively, significantly higher than under 24-hour light (1.21 cm) and natural condition (1.27 cm). It was concluded that temperature was a main factor in seed germination, and seedling growth was mainly influenced by light regime.

[Dynamics of carbon and nitrogen storages in plant-soil system during desertification process in Horqin sandy land].

Organic carbon and nitrogen storages in plant-soil system were measured at different desertification stages (potential, light, moderate, severe, and most-severe) in Horqin sandy land. From potential desertification to light, moderate, severe, and most-severe desertification, total biomass (aboveground and belowground) carbon storages decrease by 26.4%, 51.0%, 79.0%, and 91.0%, respectively, while total biomass nitrogen storages decrease by 33.6%, 66.9%, 87.4%, and 93.2%, soil organic carbon storages by 52.2%, 75.9%, 87.0% , and 90.1%, and soil nitrogen storages by 43.5%, 71.0%, 81.3%, and 82.7%, respectively. The carbon and nitrogen storages in plant-soil system are in the order: potential (C: 5 266 g x m(-2) and N: 534 g m(-2)) >light (C: 2619 g x m(-2) and N: 303 g x m(-2)) >moderate (C: 1368 g x m(-2) and N: 156 g x m(-2)) >severe (C: 715 g x m(-2) and N: 99 g x m(-2))>most severe (C: 517 g x x m(-2) and N: 91 g x m(-2)). The biomass carbon and nitrogen storages decline more rapidly at later desertification stage (from severe to most-severe) than initial stage (from potential to light), while soil carbon and nitrogen decline more rapidly at initial stage. There is a greater proportional decline in soil carbon than in nitrogen during desertification process. The biomass nitrogen storages decline more rapidly than carbon at initial stage, however, the case is reverse at later stage.