منابع مشابه
The Mesoproterozoic – no “boring billion”
The authors show that the Mesoproterozoic (1.6-1.0 bn year before present) was no “boring billion” but a “bustling billion” - not only with Stromatolites and their apex in the Calymmian and Ectasian but also with the presence of multicellular organisms. To make it visible a graphical reconstruction was created. For a long time, it was assumed that there existed no noteworthy biosphere on Earth ...
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The global energy market provides humans with about 370 exajoules of energy per year, which is equivalent to about 170 million barrels of oil per day (Box 1) or about 11.73 terrawatts (TW) per hour [1]. Approximately 95% of this energy comes from fossil fuels. Additionally, the International Energy Agency suggests that direct combustion of plant biomass provides about one-third of the energy ne...
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Heme oxygenases (HOs) are rate-limiting enzymes that catalyze the conversion of heme into equimolar amounts of biliverdin, carbon monoxide (CO), and iron.1 Biliverdin is subsequently reduced to bilirubin pigment by biliverdin reductase.2 The heme oxygenases consist of 2 major isoforms, HO-1 and HO-2. Whereas HO-2 is constitutively produced within the brain, testes, and the endothelium, HO-1 gen...
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Ethanol is a biofuel that is used as a replacement for approximately 3% of the fossil-based gasoline consumed in the world today. Most of this biofuel is produced from sugarcane in Brazil and corn in the United States. We present here the rationale for the ethanol program in Brazil, its present 'status' and its perspectives. The environmental benefits of the program, particularly the contributi...
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ژورنال
عنوان ژورنال: Science
سال: 2006
ISSN: 0036-8075,1095-9203
DOI: 10.1126/science.1130034