نتایج جستجو برای: 20th century
تعداد نتایج: 117401 فیلتر نتایج به سال:
[1] Recent and long term variations in ice extent on Kilimanjaro are investigated in the context of 20th century climate change in East Africa. Quickbird satellite data show that the areal extent of glaciers on Kilimanjaro is 2.51 km in February 2003. To assess glacier retreat on Kilimanjaro two glacier systems are identified: (1) plateau ( 5700 m) and (2) slope (<5700 m). Vertical wall retreat...
Analyses of underground temperature measurements from 358 boreholes in eastern North America, central Europe, southern Africa, and Australia indicate that, in the 20th century, the average surface temperature of Earth has increased by about 0.5 degreesC and that the 20th century has been the warmest of the past five centuries. The subsurface temperatures also indicate that Earth's mean surface ...
The observed global warming of the past century occurred primarily in two distinct 20-year periods, from 1925 to 1944 and from 1978 to the present. Although the latter warming is often attributed to a human-induced increase of greenhouse gases, causes of the earlier warming are less clear because this period precedes the time of strongest increases in human-induced greenhouse gas (radiative) fo...
Three worldwide (pandemic) outbreaks of influenza occurred in the 20th century: in 1918, 1957, and 1968. The latter 2 were in the era of modern virology and most thoroughly characterized. All 3 have been informally identified by their presumed sites of origin as Spanish, Asian, and Hong Kong influenza, respectively. They are now known to represent 3 different antigenic subtypes of influenza A v...
In this study, we present the results of the investigation of diachronic stylistic changes in 20th century religious texts in two major English language varieties – British and American. We examined a total of 146 stylistic features, divided into three main feature sets: (average sentence length, Automated readability index, lexical density and lexical richness), part-of-speech frequencies and ...
In this survey of the history of constructivism, more space has been devoted to early developments (up till ca 1965) than to the work of the last few decades. Not only because most of the concepts and general insights have emerged before 1965, but also for practical reasons: much of the recent work is of a too technical and complicated nature to be described adequately within the limits of this...
Contents 1. Introduction. 2. Models of PDE 's in the 18th and 19th century. 3. Methods of calculating solutions in the 19th century. 4. Developments of rigorous theories of solvability in the last decades of the 19th century. 5. The period 18901900: the beginning of modern PDE and the work of Poincare. 6. The Hilbert programs. 7. S. Bernstein and the beginning of a priori estimates. 8. Solvabil...
A scientific framework is described in which scientists are cast as problem-solvers, and problems as solved when data are mapped to models. This endeavor is limited by finite attentional capacity which keeps depth of understanding complementary to breadth of vision; and which distinguishes the process of science from its products, scientists from scholars. All four aspects of explanation descri...
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