Long-term analyses of vegetation succession after catastrophic events are of high interest for an improved understanding of succession dynamics. However, in many studies such analyses were restricted to plot-based mea...Long-term analyses of vegetation succession after catastrophic events are of high interest for an improved understanding of succession dynamics. However, in many studies such analyses were restricted to plot-based measurements. Contrarily, spatially continuous observations of succession dynamics over extended areas and timeperiods are sparse. Here, we applied a change vector analysis(CVA) to investigate vegetation succession dynamics at Mount St. Helens after the great volcanic eruption in 1980 using Landsat. We additionally applied a supervised random forest classification using Sentinel-2 data to map the currently prevailing vegetation types. Change vector analysis was performed with the normalized difference vegetation index(NDVI) and the urban index(UI) for three subsequent decades after the eruption as well as for the whole observation time between 1984 and 2016. The influence of topography on the current vegetation distribution was examined by comparing altitude, slope angles and aspect values of vegetation classes derived by the random forest classification. WilcoxRank-Sum test was applied to test for significant differences between topographic properties of the vegetation classes inside and outside of the areas affected by the eruption. For the full time period, a total area of 516 km2 was identified as re-vegetated, whereas the area and magnitude of re-growing vegetation decreased during the three decades and migrated closer to the volcanic crater. Vegetation losses were mainly observed in regions unaffected by the eruption and related mostly to timber harvesting. The vegetation type classification reached a high overall accuracy of approximately 90%. 36 years after the eruption, coniferous and deciduous trees have established at formerly devastated areas dominating with a proportion of 66%, whereas shrubs are more abundant in riparian zones. Sparse vegetation dominates at regions very close to the crater. Elevation was found to have a great influence on the reestablishment and distribution of the vegetation classes within the devastated areas showing in almost all cases significant differences in altitude distribution. Slope was less important for the different classes-only representing significantly higher values for meadows, whereas aspect seems to have no notable influence on the reestablishment of vegetation at Mount St. Helens. We conclude that major vegetation succession dynamics after catastrophic events can be assessed and characterized over large areas from freely available remote sensing data and hence contribute to an improved understanding of succession dynamics.展开更多
The Beta-Atla-Themis(BAT)region on Venus is characterized by large volcanic rises,major rift zones(chasmata),radiating,linear,and circumferential grabenfissure systems,and coronae.Its most prominent features
英语阅读对学生的英语学习起着重要的作用,如果小学英语教师能灵活巧妙地渗透、运用英语阅读技巧和策略,帮助小学生有效地学习和阅读英语故事或短文,将会为他们今后的英语学习奠定良好的基础。Before reading1.Greet the Students and h...英语阅读对学生的英语学习起着重要的作用,如果小学英语教师能灵活巧妙地渗透、运用英语阅读技巧和策略,帮助小学生有效地学习和阅读英语故事或短文,将会为他们今后的英语学习奠定良好的基础。Before reading1.Greet the Students and have a free talk2.Game:Feel the blind’s feelings T:Would you like to feel the blind’s feelings?OK,please close your eyes,and follow me to draw a round face,two big eyes,and a small mouth,a nose and two ears.展开更多
Jointly sponsored by the CPAFFC, the China International Friendship Cities Association, the Publicity Department of the CPC Hubei Provincial Committee, the Department of Culture of Hubei Province and Hubei Internation...Jointly sponsored by the CPAFFC, the China International Friendship Cities Association, the Publicity Department of the CPC Hubei Provincial Committee, the Department of Culture of Hubei Province and Hubei International Cultural Exchange Center, The Dream of Helen, a largescale modern dance drama commemorating American friend Helen Foster Snow, was premiered at Qintai Grand Theatre in Wuhan on July 23.展开更多
Helen Ludeberg（1908-1999）是洛杉机最受尊敬的画家之一。她主要以1930、1940年代敏于传达心理的肖像作品而被艺术界认可。但在1950年代，她开始运用抽象的几何图形来表达自然的沉寂。近日，Helen Ludeberg作品巡回展在美国举行，展...Helen Ludeberg（1908-1999）是洛杉机最受尊敬的画家之一。她主要以1930、1940年代敏于传达心理的肖像作品而被艺术界认可。但在1950年代，她开始运用抽象的几何图形来表达自然的沉寂。近日，Helen Ludeberg作品巡回展在美国举行，展出了她大约四十幅画作，其作品显示出震慑人心的力量。展开更多
In the dozen years since returning to her birth country,Helen Feng has been a vital force in the Mainland music scene:as a cultural commentator and host of The Rock Show,a creative entrepreneur with the FakeMusicMedia...In the dozen years since returning to her birth country,Helen Feng has been a vital force in the Mainland music scene:as a cultural commentator and host of The Rock Show,a creative entrepreneur with the FakeMusicMedia collective she co-founded;and the frontwoman for three seminal groups.Often dubbed the'Queen of Beijing Rock;she's closing in on her crowning achievement,as her current group Nova Heart storms through the country to support their highly anticipated self-titled debut album.展开更多
Helen Nail has Long been one of our favorite spots to get our talons preened,but the latest branch of the popular salon might just have climbed to the top of our prime spa choices in Shanghai.
In the dozen years since returning to her birth country,Helen Feng has been a vital force in the Mainland music scene.As a cuttural commentator as host of The Rock Show.As a creative entrepreneur with the FakeMusicMed...In the dozen years since returning to her birth country,Helen Feng has been a vital force in the Mainland music scene.As a cuttural commentator as host of The Rock Show.As a creative entrepreneur with the FakeMusicMedia collective she co-founded.And as the front woman for three seminal groups.Often dubbed the'Queen of Beiing rock,'she's closing in on her crowning achievement,as her current group Nova Heart storms through the country to support their highly anticipated self-titled debut album.展开更多
Benedict is an award-winning novelist and non-fiction writer specializing in social injustice.Her non-fiction book The Lonely Soldier reflects the impact of war on violence against women.Female soldiers are always the...Benedict is an award-winning novelist and non-fiction writer specializing in social injustice.Her non-fiction book The Lonely Soldier reflects the impact of war on violence against women.Female soldiers are always the victims of violence,before,during,and after serving in the Iraq War.This thesis aims to explore their trauma and illuminate the book’s meaning.展开更多
海伦·朗基诺（Helen E.Longino）,女,国际知名科学哲学家。1973年在约翰·霍普金斯大学获哲学博士学位。现任职于美国斯坦福大学哲学系（2005—至今）,C.I.Lewis教授。她曾经担任斯坦福大学哲学系主任（2008.09—2012.08）,美...海伦·朗基诺（Helen E.Longino）,女,国际知名科学哲学家。1973年在约翰·霍普金斯大学获哲学博士学位。现任职于美国斯坦福大学哲学系（2005—至今）,C.I.Lewis教授。她曾经担任斯坦福大学哲学系主任（2008.09—2012.08）,美国科学哲学学会主席（2013.01—2014.11）。主要研究领域为：科学哲学、社会认识论和女性主义哲学。代表作有：《作为社会知识的科学》（Science as Social Knowledge,展开更多
文摘Long-term analyses of vegetation succession after catastrophic events are of high interest for an improved understanding of succession dynamics. However, in many studies such analyses were restricted to plot-based measurements. Contrarily, spatially continuous observations of succession dynamics over extended areas and timeperiods are sparse. Here, we applied a change vector analysis(CVA) to investigate vegetation succession dynamics at Mount St. Helens after the great volcanic eruption in 1980 using Landsat. We additionally applied a supervised random forest classification using Sentinel-2 data to map the currently prevailing vegetation types. Change vector analysis was performed with the normalized difference vegetation index(NDVI) and the urban index(UI) for three subsequent decades after the eruption as well as for the whole observation time between 1984 and 2016. The influence of topography on the current vegetation distribution was examined by comparing altitude, slope angles and aspect values of vegetation classes derived by the random forest classification. WilcoxRank-Sum test was applied to test for significant differences between topographic properties of the vegetation classes inside and outside of the areas affected by the eruption. For the full time period, a total area of 516 km2 was identified as re-vegetated, whereas the area and magnitude of re-growing vegetation decreased during the three decades and migrated closer to the volcanic crater. Vegetation losses were mainly observed in regions unaffected by the eruption and related mostly to timber harvesting. The vegetation type classification reached a high overall accuracy of approximately 90%. 36 years after the eruption, coniferous and deciduous trees have established at formerly devastated areas dominating with a proportion of 66%, whereas shrubs are more abundant in riparian zones. Sparse vegetation dominates at regions very close to the crater. Elevation was found to have a great influence on the reestablishment and distribution of the vegetation classes within the devastated areas showing in almost all cases significant differences in altitude distribution. Slope was less important for the different classes-only representing significantly higher values for meadows, whereas aspect seems to have no notable influence on the reestablishment of vegetation at Mount St. Helens. We conclude that major vegetation succession dynamics after catastrophic events can be assessed and characterized over large areas from freely available remote sensing data and hence contribute to an improved understanding of succession dynamics.
文摘The Beta-Atla-Themis(BAT)region on Venus is characterized by large volcanic rises,major rift zones(chasmata),radiating,linear,and circumferential grabenfissure systems,and coronae.Its most prominent features
文摘英语阅读对学生的英语学习起着重要的作用,如果小学英语教师能灵活巧妙地渗透、运用英语阅读技巧和策略,帮助小学生有效地学习和阅读英语故事或短文,将会为他们今后的英语学习奠定良好的基础。Before reading1.Greet the Students and have a free talk2.Game:Feel the blind’s feelings T:Would you like to feel the blind’s feelings?OK,please close your eyes,and follow me to draw a round face,two big eyes,and a small mouth,a nose and two ears.
文摘Jointly sponsored by the CPAFFC, the China International Friendship Cities Association, the Publicity Department of the CPC Hubei Provincial Committee, the Department of Culture of Hubei Province and Hubei International Cultural Exchange Center, The Dream of Helen, a largescale modern dance drama commemorating American friend Helen Foster Snow, was premiered at Qintai Grand Theatre in Wuhan on July 23.
文摘In the dozen years since returning to her birth country,Helen Feng has been a vital force in the Mainland music scene:as a cultural commentator and host of The Rock Show,a creative entrepreneur with the FakeMusicMedia collective she co-founded;and the frontwoman for three seminal groups.Often dubbed the'Queen of Beijing Rock;she's closing in on her crowning achievement,as her current group Nova Heart storms through the country to support their highly anticipated self-titled debut album.
文摘Helen Nail has Long been one of our favorite spots to get our talons preened,but the latest branch of the popular salon might just have climbed to the top of our prime spa choices in Shanghai.
文摘In the dozen years since returning to her birth country,Helen Feng has been a vital force in the Mainland music scene.As a cuttural commentator as host of The Rock Show.As a creative entrepreneur with the FakeMusicMedia collective she co-founded.And as the front woman for three seminal groups.Often dubbed the'Queen of Beiing rock,'she's closing in on her crowning achievement,as her current group Nova Heart storms through the country to support their highly anticipated self-titled debut album.
文摘Benedict is an award-winning novelist and non-fiction writer specializing in social injustice.Her non-fiction book The Lonely Soldier reflects the impact of war on violence against women.Female soldiers are always the victims of violence,before,during,and after serving in the Iraq War.This thesis aims to explore their trauma and illuminate the book’s meaning.
文摘海伦·朗基诺（Helen E.Longino）,女,国际知名科学哲学家。1973年在约翰·霍普金斯大学获哲学博士学位。现任职于美国斯坦福大学哲学系（2005—至今）,C.I.Lewis教授。她曾经担任斯坦福大学哲学系主任（2008.09—2012.08）,美国科学哲学学会主席（2013.01—2014.11）。主要研究领域为：科学哲学、社会认识论和女性主义哲学。代表作有：《作为社会知识的科学》（Science as Social Knowledge,
