Specifically, the blue-green algae (or cyanobacteria) that emerged and proliferated about 2.4 billion years ago would have been able to produce more oxygen as a metabolic by-product because Earth's ...

A PaO2 test measures partial pressure of oxygen, or PaO2—the oxygen pressure in arterial blood. The PaO2 reflects how well oxygen is able to move from the lungs to the blood. It is often altered by ...

1 School of Economics and Trade, Hunan University, Changsha, China 2 School of Economics and Management, Xiangnan University, Chenzhou, China Introduction: The digital economy is reshaping economic ...