Research on Texas savannas : fractional woody cover mapping, potential woody cover modelling, and woody plant encroachment analysis

Tested in Texas savannas of a wide rainfall gradient, this dissertation endeavors to (1) map fractional woody cover at Landsat scale, for close and continuous woody plant encroachment monitoring, (2) model the pattern of potential woody cover over the present rainfall gradient, for implication of the end-point of woody plant encroachment, (3) analyze the rate and effect factors of woody plant encroachment under the regional context, for pertinent savanna management strategy. Web-Enabled Landsat Data (WELD) was used to calibrate the Salford Systems’ Classification and Regression Trees (CART) against training data of fractional woody cover derived from 1m resolution digital orthophotos. The CART model output was verified against an independent test data. This study provides a way to accurately monitor woody plant encroachment across savanna ecosystems at a fine spatial scale, and sets up a protocol for landscape components mapping at sub-pixel level in other ecosystems. The pattern of potential woody cover was modelled over the wide rainfall gradient at Landsat scale (30m) and MODIS scale (500m) respectively. While a positive linear relationship between potential woody cover and mean annual precipitation (MAP) was revealed at Landsat scale, a prominent three-segment relationship was observed at MODIS scale. This discrepancy corroborates the scale dependency of the primary determinants of savanna woody plant density. According to the three-segment pattern at MODIS scale, Texas savannas are divided into arid savanna (MAP 735mm). Analysis of the encroachment of Ashe juniper at its early life stage (initial ~20 years) at local (hectare) scale suggests that water availability has a significant positive effect on the encroachment rate in semi-arid savanna, but not in mesic savanna. In addition, a quadratic relationship was revealed between the encroachment rate and woody plant density in mesic savanna. That is, the encroachment rate increases with woody plant density by a threshold density, then starts decreasing with woody plant density. These results demonstrate that regional context such as rainfall and biological traits of woody species is critical to understand the trend of woody plant encroachment.Geography and the Environmen

The Study on Translation of Culture-loaded Words in Aerial ChinaⅠ- Jiangxi from the Perspective of Semantic and Communicative Translation

Aerial ChinaⅠ- Jiangxi has been widely accepted by foreign audiences. In this documentary, there are many culture-loaded words with Jiangxi cultural characteristics. We all know that the translation of Chinese culturally-loaded words has long been a tricky problem. Take the translation of culture loaded words in Aerial ChinaⅠ- Jiangxi as an example, this paper discusses how Newmark's communicative translation and semantic translation theory are applied to the translation of Chinese culture loaded words. It is considered that semantic translation and communicative translation are not completely opposite but complement each other. Good translation works are usually the perfect combination of the two. In order to help translators better translate culture loaded words and achieve the real purpose of cross-cultural communication

Molecular and cellular mediators in radiation-induced lung injury

Radiation-induced lung injury is a common adverse effect in patients receiving thoracic irradiation and for which, there is currently no effective therapy. Using a murine model of thoracic irradiation, we found that mice deficient in either the chemokine CCL3 or one of its receptors, CCR1, are significantly protected from radiation lung injury. This protected phenotype includes improved survival, virtually no pneumonitis or fibrosis, and preserved lung function when compared to wild-type mice. We further showed that a specific CCR1 inhibitor, BX471 provided similar protection. Therefore, CCR1 is a promising target for reducing radiation lung injury. To investigate the mechanisms by which CCL3/CCR1 signalling mediates radiation lung injury, we evaluated their influence on lung inflammation after irradiation. When compared with irradiated WT mice, irradiated CCL3- and CCR1-deficient mice had less lung infiltration of CD4+ and CD8+ T cells; however, CD4-deficient mice showed only partial protection, while CD8-deficient mice had slightly worse fibrosis. We further analyzed inflammatory cytokines and different subsets of CD4+ lymphocytes, TH1, TH2, TH17 and Treg cells, in our model. We found no differences in lung Foxp3+ Treg cells between WT and CCR1-deficient mice. Notably however, irradiated CCR1-deficient mice had less mRNA expression of the TH2 cytokines, IL-4 and IL-13, suggesting that TH2 cells may mediate radiation lung injury. In addition, the TH2-enhanced IL-10/12 double knockout mice (IL-10/12-/-) have increased expression of IL-13 and IL-4 with an associated earlier onset and enhanced degree of lung fibrosis. Even more striking was our finding that irradiated IL-10/12-/- mice had an earlier onset of increased IL-17 mRNA expression, as well as increased lung infiltration of TH17 cells, suggesting that IL-17 cells may also be important mediators in radiation lung injury. In summary, our studies show that CCL3 and its receptor, CCR1, are key mediators of radiation lung injury that act at least in part by recruiting TH17 and TH2 cells into the irradiated lungs. Furthermore, our findings suggest that the specific inhibitor of CCR1, BX471, looks promising as a potential therapeutic agent for ameliorating radiation lung injury

p120-Catenin Down-Regulation and Epidermal Growth Factor Receptor Overexpression Results in a Transformed Epithelium That Mimics Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is an aggressive malignancy with a poor prognosis due to its highly invasive and metastatic potential. The molecular pathogenesis underlying the invasive mechanism of ESCC is not well known because of the lack of existing models to study this disease. p120-Catenin (p120ctn) and the epidermal growth factor receptor (EGFR) have each been implicated in several cancers, including ESCC. p120ctn is down-regulated in 60% of ESCC tumors, whereas EGFR is the most commonly overexpressed oncogene in ESCC. For these reasons, we investigated the cooperation between p120ctn and EGFR and its effect on ESCC invasion. We show that p120ctn down-regulation is commonly associated with EGFR overexpression. By using a three-dimensional culture system, we demonstrate that the inverse relationship between p120ctn and EGFR has biological implications. Specifically, p120ctn down-regulation coupled with EGFR overexpression in human esophageal keratinocytes (EPC1-PE) was required to promote invasion. Morphological comparison of EPC1-PE cells grown in three-dimensional culture and human ESCC revealed identical features, including significantly increased cellularity, nuclear grade, and proliferation. Molecular characteristics were measured by keratin expression patterns, which were nearly identical between EPC1-PE cells in three-dimensional culture and ESCC samples. Altogether, our analyses have demonstrated that p120ctn down-regulation and EGFR overexpression are able to mimic human ESCC in a relevant three-dimensional culture model