Estimation of land production and its response to cultivated land conversion in North China Plain

Major State Basic Research Development Program of China 2010CB950904;National Natural Science Foundation of China 70503025 40801231;Chinese Academy of Sciences KZCX2-YW-305-2Food safety and its related influencing factors in China are the hot research topics currently, and cultivated land conversion is one of the significant factors influencing food safety in China. Taking the North China Plain as the study area, this paper examines the changes of cultivated land area using satellite images, estimates land productivity from 1985 to 2005 using the model of Estimation System for Land Productivity (ESLP), and analyzes the impact of cultivated land conversion on the land production. Compared with the grain yield data from statistical yearbooks, the results indicate that ESLP model is an effective tool for estimating land productivity. Land productivity in the North China Plain showed a slight decreasing trend from 1985 to 2005, spatially, increased from the north to the south gradually, and the net changes varied in different areas. Cultivated land area recorded a marginal decrease of 8.0 x 10(5) ha, mainly converted to other land uses. Cultivated land conversion had more significant negative impacts on land production than land productivity did. Land production decreased by about 6.48 x 10(6) t caused by cultivated land conversion between 1985 and 2005, accounting for 91.9% of the total land production reduction. Although the land productivity increased in Anhui and Jiangsu provinces, it can not offset the overall adverse effects caused by cultivated land conversion. Therefore, there are significant meanings to control the cultivated land conversion and improve the land productivity for ensuring the land production in the North China Plain

Effects of Elevated CO2 and N Addition on Growth and N2 Fixation of a Legume Subshrub (Caragana microphylla Lam.) in Temperate Grassland in China

It is well demonstrated that the responses of plants to elevated atmospheric CO2 concentration are species-specific and dependent on environmental conditions. We investigated the responses of a subshrub legume species, Caragana microphylla Lam., to elevated CO2 and nitrogen (N) addition using open-top chambers in a semiarid temperate grassland in northern China for three years. Measured variables include leaf photosynthetic rate, shoot biomass, root biomass, symbiotic nitrogenase activity, and leaf N content. Symbiotic nitrogenase activity was determined by the C2H2 reduction method. Elevated CO2 enhanced photosynthesis and shoot biomass by 83% and 25%, respectively, and the enhancement of shoot biomass was significant only at a high N concentration. In addition, the photosynthetic capacity of C. microphylla did not show down-regulation under elevated CO2. Elevated CO2 had no significant effect on root biomass, symbiotic nitrogenase activity and leaf N content. Under elevated CO2, N addition stimulated photosynthesis and shoot biomass. By contrast, N addition strongly inhibited symbiotic nitrogenase activity and slightly increased leaf N content of C. microphylla under both CO2 levels, and had no significant effect on root biomass. The effect of elevated CO2 and N addition on C. microphylla did not show interannual variation, except for the effect of N addition on leaf N content. These results indicate that shoot growth of C. microphylla is more sensitive to elevated CO2 than is root growth. The stimulation of shoot growth of C. microphylla under elevated CO2 or N addition is not associated with changes in N2-fixation. Additionally, elevated CO2 and N addition interacted to affect shoot growth of C. microphylla with a stimulatory effect occurring only under combination of these two factors

Molecular Characterization of Transcriptional Regulation of rovA by PhoP and RovA in Yersinia pestis

BACKGROUND: Yersinia pestis is the causative agent of plague. The two transcriptional regulators, PhoP and RovA, are required for the virulence of Y. pestis through the regulation of various virulence-associated loci. They are the global regulators controlling two distinct large complexes of cellular pathways. METHODOLOGY/PRINCIPAL FINDINGS: Based on the LacZ fusion, primer extension, gel mobility shift, and DNase I footprinting assays, RovA is shown to recognize both of the two promoters of its gene in Y. pestis. The autoregulation of RovA appears to be a conserved mechanism shared by Y. pestis and its closely related progenitor, Y. pseudotuberculosis. In Y. pestis, the PhoP regulator responds to low magnesium signals and then negatively controls only one of the two promoters of rovA through PhoP-promoter DNA association. CONCLUSIONS/SIGNIFICANCE: RovA is a direct transcriptional activator for its own gene in Y. pestis, while PhoP recognizes the promoter region of rovA to repress its transcription. The direct regulatory association between PhoP and RovA bridges the PhoP and RovA regulons in Y. pestis

Prevalence and trend of hepatitis C virus infection among blood donors in Chinese mainland: a systematic review and meta-analysis

<p>Abstract</p> <p>Background</p> <p>Blood transfusion is one of the most common transmission pathways of hepatitis C virus (HCV). This paper aims to provide a comprehensive and reliable tabulation of available data on the epidemiological characteristics and risk factors for HCV infection among blood donors in Chinese mainland, so as to help make prevention strategies and guide further research.</p> <p>Methods</p> <p>A systematic review was constructed based on the computerized literature database. Infection rates and 95% confidence intervals (95% CI) were calculated using the approximate normal distribution model. Odds ratios and 95% CI were calculated by fixed or random effects models. Data manipulation and statistical analyses were performed using STATA 10.0 and ArcGIS 9.3 was used for map construction.</p> <p>Results</p> <p>Two hundred and sixty-five studies met our inclusion criteria. The pooled prevalence of HCV infection among blood donors in Chinese mainland was 8.68% (95% CI: 8.01%-9.39%), and the epidemic was severer in North and Central China, especially in Henan and Hebei. While a significant lower rate was found in Yunnan. Notably, before 1998 the pooled prevalence of HCV infection was 12.87% (95%CI: 11.25%-14.56%) among blood donors, but decreased to 1.71% (95%CI: 1.43%-1.99%) after 1998. No significant difference was found in HCV infection rates between male and female blood donors, or among different blood type donors. The prevalence of HCV infection was found to increase with age. During 1994-1995, the prevalence rate reached the highest with a percentage of 15.78% (95%CI: 12.21%-19.75%), and showed a decreasing trend in the following years. A significant difference was found among groups with different blood donation types, Plasma donors had a relatively higher prevalence than whole blood donors of HCV infection (33.95% <it>vs </it>7.9%).</p> <p>Conclusions</p> <p>The prevalence of HCV infection has rapidly decreased since 1998 and kept a low level in recent years, but some provinces showed relatively higher prevalence than the general population. It is urgent to make efficient measures to prevent HCV secondary transmission and control chronic progress, and the key to reduce the HCV incidence among blood donors is to encourage true voluntary blood donors, strictly implement blood donation law, and avoid cross-infection.</p

Azimuthal Charged-Particle Correlations and Possible Local Strong Parity Violation

Parity-odd domains, corresponding to nontrivial topological solutions of the QCD vacuum, might be created during relativistic heavy-ion collisions. These domains are predicted to lead to charge separation of quarks along the system’s orbital momentum axis. We investigate a three-particle azimuthal correlator which is a P even observable, but directly sensitive to the charge separation effect. We report measurements of charged hadrons near center-of-mass rapidity with this observable in Au+Au and Cu+Cu collisions at √sNN=200  GeV using the STAR detector. A signal consistent with several expectations from the theory is detected. We discuss possible contributions from other effects that are not related to parity violation

Inequalities involving unitarily invariant norms and operator monotone functions

Let parallel to . parallel to be a unitarily invariant norm on matrices. For matrices A, B, X with A, B positive semidefinite and X arbitrary, we prove that the function t --&gt; parallel to \A(t) x B1-tr) parallel to . parallel to \A(1-t) x B-t\(r) parallel to is convex on [0, 1] for each r > 0. This convexity result interpolates the matrix Cauchy-Schwarz inequality parallel to \A(1/2) x B-1/2\(r) parallel to(2) less than or equal to parallel to \AX\(r) parallel to . parallel to \XB\(r) parallel to due to R. Bhatia and C. Davis [Linear Algebra Appl. 223/224 (1995) 119], and also it generalizes A.W. Marshall and I. OLkin's [Pacific J. Math. 15 (1965) 241] result that the condition number parallel toA(s)parallel to . parallel toA(-s)parallel to is increasing in s > 0. We prove that if f (t) is a nonnegative operator monotone function on [0, infinity) and parallel to parallel to is a normalized unitarily invariant norm, then f (parallel to X parallel to) less than or equal to parallel to f(\X parallel to for every matrix X. The special case when f (t) = t(r) (0 &lt; r less than or equal to 1) is used to consider the monotonicity of p --&gt; parallel to A(p) + B-p parallel to (1/p) as well as p --&gt; parallel to (A(p)+B-p) (1/p) parallel to. Furthermore, we obtain some norm inequalities of Hblder and Minkowski types related to the expression parallel to \A\(p)+\B\(p) parallel to (1/p). For example, comparisons are made between parallel to C*A + D*B parallel to and parallel to \A\(p)+\B\(p). parallel to \C\(q)+\D\(q) parallel to(1/q), where p(-1)+q(-1) = 1. (C) 2002 Elsevier Science Inc. All rights reserved.Mathematics, AppliedMathematicsSCI(E)12ARTICLE151-16934

Solubility of N-tert-Butylbenzothiazole-2-sulfenamide in Several Pure and Binary Solvents

The solubility of N-tert-butylbenzothiazole-2-sulfenamide (TBBS) in six pure solvents (methanol, ethanol, toluene, 2-propanol, 1-butanol, and tert-butylamine) and three binary solvents (methanol + water, ethanol + water, and tert-butylamine + water) was measured in a temperature range between 273.2 and 313.2 K using a gravimetric determination under a pressure of 0.101 MPa. The initial mole fraction of methanol, ethanol, or tert-butylamine in the binary solvents was in the range of 0.4 to 1.0. The experimental data show that the solubility of TBBS increases as the temperature increases in both the pure and binary solvents. The solubility of TBBS in the six pure solvents has the following sequence: x1, tert-butylamine > x1, toluene > x1, 1-butanol > x1, ethanol > x1, 2-propanol > x1, methanol. The high-temperature solubility of TBBS in tert-butylamine at 318.2–343.2 K under a pressure from 0.156 to 0.213 MPa was also determined using an approach based on turbidity measurement. The experimental solubility data can be correlated by the following four thermodynamic models: the modified Apelblat equation, the λh equation, the CNIBS/R-K model, and the NRTL model. The results showed that the solubility of TBBS fit best with the modified Apelblat equation in both the pure and binary solvents

Properties and analytical application of room temperature phosphorescence of 1-bromonaphthalene induced by p-octylpolyethylene glycol phenylether in aqueous beta-cyclodextrin solution

Intense room temperature phosphorescence of 1-bromonaphthalene (1-BrN) induced by p-octylpolyethylene glycol phenylether was studied in aqueous beta-cyclodextrin solution. The mode of inclusion complex formation was approached. The optimal conditions were obtained. Interferences of foreign substances with phosphorescence were examined. The phosphorescence intensity is proportional to the concentration of 1-BrN in the range 0 similar to 5.18 mu g ml(-1). The recovery is 90-102% and the relative standard deviation is less than 4.5%. The proposed method is simple and convenient. (C) 1997 Elsevier Science B.V

Pulverized Coal Combustion Catalyzed by CeO2 Based on Iron-Making System

Differential thermal analysis (DTA) and layer firing reactors were employed to investigate effect of CeO2 on anthracite combustion, indicating that CeO2 decreased ignition temperature of anthracite, and increased its combustion rate. To improve catalytic effect, CeO2 was sieved to four different particles, revealing that CeO2 with smaller particle has better effect at range of given coal particle. If catalysts are nano-size particles, the effect will be improved more. However, excessive overage of coal particle surface by nano-size catalyst will result in the reducing of contact area between oxygen and coal particle, thus hindering the evolution of coal combustion. Consequently, we should reduce the additive of catalyst. In addition, effects of heating rate and oxygen enrichment ratio on anthracite combustion catalyzed by CeO2 were investigate, showing that the higher heating rate and oxygen enrichment ratio, the better catalytic effect