منابع مشابه
Rainfall regimes of the Green Sahara
During the "Green Sahara" period (11,000 to 5000 years before the present), the Sahara desert received high amounts of rainfall, supporting diverse vegetation, permanent lakes, and human populations. Our knowledge of rainfall rates and the spatiotemporal extent of wet conditions has suffered from a lack of continuous sedimentary records. We present a quantitative reconstruction of western Sahar...
متن کاملGreen trees for greenhouse gases: a fair trade-off?
While forests retain carbon in plants, detritus, and soils, utility companies spew it into the air as carbon dioxide, the main greenhouse gas behind global warming. Industrial carbon dioxide emissions aren't currently regulated by federal law, but a number of companies are trying to address the problem voluntarily by launching carbon sequestration programs in heavily forested countries, where c...
متن کاملGreen Noctiluca scintillans: a dinoflagellate with its own greenhouse
The effect of irradiance on photosynthesis of the green form of the dinoflagellate Noctiluca scintillans was studied. Photosynthesis, measured in cells collected from the field and without the addition of prey, increased with irradiance to ca. 200 ng C cell–1 d–1 at an irradiance of ~250 to 300 μmol photons m–2 s–1. N. scintillans cells were observed to prey and grow actively on a number of dif...
متن کاملDynamics of Green Sahara Periods and Their Role in Hominin Evolution
Astronomically forced insolation changes have driven monsoon dynamics and recurrent humid episodes in North Africa, resulting in green Sahara Periods (GSPs) with savannah expansion throughout most of the desert. Despite their potential for expanding the area of prime hominin habitats and favouring out-of-Africa dispersals, GSPs have not been incorporated into the narrative of hominin evolution ...
متن کاملGive the Sahara desert to a health care administrator and a few weeks later he will have to import sand.
Ziegenfuss and Sassani claimed that health administration education “would be helpful to clinicians.” Sadly, this claim can be added to the long list of redisorganization examples. In contrast, education in etymology and logic may be helpful to professors of management. Clinician means at bedside; the patient needs clinicians who possess sufficient knowledge and clinical skills to make and exec...
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ژورنال
عنوان ژورنال: Episodes
سال: 1990
ISSN: 0705-3797,2586-1298
DOI: 10.18814/epiiugs/1990/v13i2/005