Long-term observations of the Antarctic ice sheet will contribute to a quantitative evaluation and precise prediction of the sea level change induced by global changes in climate. This paper proposes an improved rigor...
Long-term observations of the Antarctic ice sheet will contribute to a quantitative evaluation and precise prediction of the sea level change induced by global changes in climate. This paper proposes an improved rigorous geometric modeling method for the declassified KH-5 ARGON satellite images collected in Antarctica in 1960s. The scanned film images are preprocessed beforehand to enhance the quality for further analysis. Systematic errors such as lens distortion and atmospheric refraction are also considered and corrected. A scheme is proposed to measure the ground control points for the historical images based on modern image mosaic and DEM products. The bundle adjustment results of four blocks in regions in East Antarctica present a geometric positioning accuracy of less than one nominal pixel resolution (140 m) in both horizontal and vertical directions, outperforming the published results. A regional DEM of the ice sheet that represents the topography in 1963 is then generated from the stereo ARGON images for the first time, the evaluation of which shows its consistency with the modern product but with great value for studying the recent change history of the ice sheet.
Human papillomaviruses (HPV) contribute to most cervical cancers and are considered to be sexually transmitted. However, papillomaviruses are often found in cancers of internal organs, including the stomach, raising t...
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Human papillomaviruses (HPV) contribute to most cervical cancers and are considered to be sexually transmitted. However, papillomaviruses are often found in cancers of internal organs, including the stomach, raising the question as to how the viruses gain access to these sites. A possible connection between blood transfusion and HPV-associated disease has not received much attention. Here we show, in rabbit and mouse models, that blood infected with papillomavirus yields infections at permissive sites with detectable viral DNA, RNA transcripts, and protein products. The rabbit skin tumours induced via blood infection displayed decreased expression of SLN, TAC1, MYH8, PGAM2, and APOBEC2 and increased expression of SDRC7, KRT16, S100A9, IL36G, and FABP9, as seen in tumours induced by local infections. Furthermore, we demonstrate that blood from infected mice can transmit the infection to uninfected animals. Finally, we demonstrate the presence of papillomavirus infections and virus-induced hyperplasia in the stomach tissues of animals infected via the blood. These results indicate that blood transmission could be another route for papillomavirus infection, implying that the human blood supply, which is not screened for papillomaviruses, could be a potential source of HPV infection as well as subsequent cancers in tissues not normally associated with the viruses.
Ice flow velocity is used to estimate ice mass changes in glaciers and is a significant indicator of the stability of the Antarctica ice sheet in global change studies. The existing regional Antarctica ice flow speed ...
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Ice flow velocity is used to estimate ice mass changes in glaciers and is a significant indicator of the stability of the Antarctica ice sheet in global change studies. The existing regional Antarctica ice flow speed maps are usually derived from radar or optical satellite observations of modern satellites since the 1970s. This paper presents a new analytical photogrammetric method for estimating Antarctica ice flow velocity fields by using film-based stereo ARGON photographs collected in the 1960s. The key of the proposed innovative method is a parallax decomposition that separates the effect of the terrain relief from the ice flow motion. An innovative implementation strategy is developed by using a framework that involves key techniques of hierarchical stereo image matching, ice flow direction determination, parallax decomposition, and ice flow speed estimation. This method is applied in the Rayner glacier in eastern Antarctica by using two sets of ARGON images with a two-month interval in 1963. The produced digital terrain model and speed map achieved a ground position accuracy of 61 m and a speed accuracy of 70 m a(-1). A comparison with recent products from 2000 to 2010 shows no significant topographic changes in the study area. Furthermore, the speed around the grounding line remained at the same level, while the speed in the ice shelf front decreased by 73 m a(-1.) The ice shelf front advanced by approximately 7 km over more than 40 years. Overall, the observation results indicate favorable conditions for the stability of the Rayner glacier-ice shelf system.
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