Evaluation of five satellite top-of-atmosphere albedo products over land

Five satellite top-of-atmosphere (TOA) albedo products over land were evaluated in this study including global products from the Advanced Very High Resolution Radiometer (AVHRR) (TAL-AVHRR), Moderate Resolution Imaging Spectroradiometer (MODIS) (TAL-MODIS), and Clouds and the Earth’s Radiant Energy System (CERES); one regional product from the Climate Monitoring Satellite Application Facility (CM SAF); and one harmonized product termed Diagnosing Earth’s Energy Pathways in the Climate system (DEEP-C). Results showed that overall, there is good consistency among these five products, particularly after the year 2000. The differences among these products in the high-latitude regions were relatively larger. The percentage differences among TAL-AVHRR, TAL-MODIS, and CERES were generally less than 20%, while the differences between TAL-AVHRR and DEEP-C before 2000 were much larger. Except for the obvious decrease in the differences after 2000, the differences did not show significant changes over time, but varied among different regions. The differences between TAL-AVHRR and the other products were relatively large in the high-latitude regions of North America, Asia, and the Maritime Continent, while the differences between DEEP-C and CM SAF in Europe and Africa were smaller. Interannual variability was consistent between products after 2000, before which the differences among the three products were much larger

Radiosensitizing effects of Sestrin2 in PC3 prostate cancer cells

Objective(s): The stress-responsive genes of Sestrin family are recognized as new tumor suppressor genes in breast carcinoma, however, the function of Sestrin family in human prostate cancer is not clear. Ionizing radiation (IR) is known to induce Sestrin gene expression in breast cancer cells. However, the response of Sestrin to IR has not been reported in PC3 prostate cancer cells. Materials and Methods: Sestrin2 expression in prostate cancer cell lines (PC3, LNCaP clone FGC, and DU145) was detected by Western blot and real-time PCR. Cell counting kit (CCK-8) was used to detect cellular proliferation. The radiosensitivity of PC3 cells was detected by clonogenic assay. Results: Sestrin2 expression in prostate cancer cell lines (PC3, LNCaP clone FGC, and DU145) is low. In vitro assays indicated that over-expressing Sestrin2 in human prostate cancer PC3 inhibited tumor proliferation. In addition, elevated Sestrin2 expression sensitized PC3 cells to IR. Conclusion: We determined Sestrin2 may function as a tumor suppressor through repressing proliferation, mediating sensitization to IR in PC3 cells

Molecular evolution of the H6 subtype influenza a viruses from poultry in eastern China from 2002 to 2010

<p>Abstract</p> <p>Background</p> <p>Although extensive data demonstrates that the majority of H6 duck isolates belonged to a single H6N2 virus lineage with a single gene constellation in southern China from 2000 to 2005, the prevalence of H6N2 virus in poultry in Eastern China is largely unknown.</p> <p>Results</p> <p>Epidemiology revealed that H6N2 viruses were the most frequently detected influenza subtypes in live bird markets from 2002 to 2008 in Eastern China, but from 2009 onwards, they were replaced with novel H6N6 viruses. We phylogenetically and antigenically analyzed 42 H6 viruses isolated mainly in domestic ducks from 2002 to 2010 in Eastern China. Surprisingly, none of these isolates grouped with the previously described H6N2 viruses which belonged to a single H6N2 virus lineage with a single gene constellation in domestic ducks in southern China from 2000 to 2005. Two distinct hemagglutinin lineages were identified and they all underwent frequent reassortment with multiple virus subtypes from the natural gene pool, but few reassortants were persistent or prevalent.</p> <p>Conclusions</p> <p>Five subtypes of H6 influenza viruses (H6N1, H6N2, H6N5, H6N6 and H6N8) cocirculated in Eastern China, which form a significant part of the natural influenza virus reservoir in domestic ducks, and significant viral reassortment is still ongoing in this species.</p

A Novel Road Extraction Algorithm for High Resolution Remote Sensing Images

Abstract: Automatic road extraction from the high resolution remote sensing images is of great importance in intelligent transportation and image processing. Hence, in this paper, an effective road extraction algorithm for high resolution remote sensing images based on the circular projection transformation is proposed. The main idea of the proposed algorithm lies in that the road extraction results are obtained by selecting a suitable initial template, and then search the matched templates through moving the initial template in two directions. Firstly, the circular projection vector of the initial template is achieved by calculating the circular projection value at a specific radius. Secondly, the optimal radius of the circle in circular projection transformation and the length of the seeking step and the seeking angle are determined. Thirdly, for each seeking step the similarity between the target template and the initial template is computed, and the template with the highest similarity is chosen. Finally, roads can be detected by the correct direction by exchanging the first two detected points. To make performance evaluation, the IKONOS dataset is utilized and DMES and AUA algorithm are compared. The experimental results demonstrate that the proposed algorithm can automatic the roads from high resolution remote sensing images effectively and efficiently

IPO initial returns in China: Underpricing or overvaluation?

This paper separates the amount of IPO underpricing (primary market underpricing) and overvaluation (secondary market overvaluation) from the value of an IPO’s initial return to evaluate the relative importance of these two factors and their main determinants. Using data on the IPOs of 948 Chinese firms, we find that average initial returns are 66% and that underpricing and overvaluation are between 14–22% and 44–53%, respectively, depending on the method used to assess firms’ intrinsic values. In addition, while both the value of the initial return and the extent of overvaluation are significantly negatively related to post-IPO long-run stock performance, overvaluation can predict post-IPO performance better than the value of the initial return. Value uncertainty in IPOs is positively related to both underpricing and overvaluation, and both the underwriter’s reputation and the existence of pricing regulation are positively related to underpricing. Investor sentiment has a positive effect on overvaluation but has no effect or a negative effect on underpricing. Overall, our results suggest that in China overvaluation accounts for a larger proportion of the initial return than underpricing, and that underpricing and overvaluation have different determinants

Land Surface Albedo Estimation from Chinese HJ Satellite Data Based on the Direct Estimation Approach

Monitoring surface albedo at medium-to-fine resolution (&lt;100 m) has become increasingly important for medium-to-fine scale applications and coarse-resolution data evaluation. This paper presents a method for estimating surface albedo directly using top-of-atmosphere reflectance. This is the first attempt to derive surface albedo for both snow-free and snow-covered conditions from medium-resolution data with a single approach. We applied this method to the multispectral data from the wide-swath Chinese HuanJing (HJ) satellites at a spatial resolution of 30 m to demonstrate the feasibility of this data for surface albedo monitoring over rapidly changing surfaces. Validation against ground measurements shows that the method is capable of accurately estimating surface albedo over both snow-free and snow-covered surfaces with an overall root mean square error (RMSE) of 0.030 and r-square (R2) of 0.947. The comparison between HJ albedo estimates and the Moderate Resolution Imaging Spectral Radiometer (MODIS) albedo product suggests that the HJ data and proposed algorithm can generate robust albedo estimates over various land cover types with an RMSE of 0.011–0.014. The accuracy of HJ albedo estimation improves with the increase in view zenith angles, which further demonstrates the unique advantage of wide-swath satellite data in albedo estimation