To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Much can be learned from terrestrial planets that appear to have had the potential to be habitable, but failed to realize that potential. Mars shows evidence of a once hospitable surface environment. The reasons for its current state, and in particular its thin atmosphere and dry surface, are of great interest for what they can tell us about habitable zone planet outcomes. A main goal of the MAVEN mission is to observe Mars’ atmosphere responses to solar and space weather influences, and in particular atmosphere escape related to space weather ‘storms’ caused by interplanetary coronal mass ejections (ICMEs). Numerical experiments with a data-validated MHD model suggest how the effects of an observed moderately strong ICME compare to what happens during a more extreme event. The results suggest the kinds of solar and space weather conditions that can have evolutionary importance at a planet like Mars.
A review of some of the most important studies of the past several decades pertaining to the study of atomic diffusion in stellar atmospheres is presented. A brief description of various studies of radiative accelerations and diffusion calculations in stellar atmospheres is given. Several physical phenomena such as ambipolar diffusion, light-induced drift and the effect of magnetic fields on diffusion are discussed. Results from recent self-consistent model atmospheres including elemental stratification are also reviewed. Particularities of radiative acceleration calculations in stellar atmospheres as well as difficulties and future challenges related to diffusion calculations in stellar atmospheres are also presented.
World maize production in 1992–94 oscillated between 470 and 569 million t produced on about 127–132 million ha. The average yields were in the range of 3.7–4.3 t/ha, which are the highest among the most important world cereal food crops: wheat, rice and maize (FAO 1995). Its production, however, is not evenly distributed. More than 40% of world maize production comes from the United States. Maize is widely adapted between 55°N and S latitudes (Guidry 1964) and at altitudes from sea level to 3600 m in cool tropical highlands of the Andes. Adapted maize germplasm is cultivated in tropical lowlands, tropical and subtropical mid-altitudes, temperate and cool tropical highland climates.
Hybrid maize was first introduced in the United States before World War II and further development of single-cross hybrids from the 1960s in most temperate maize-growing countries has been a significant factor in increasing maize production (Hallauer et al. 1988). Hybrid maize technology is being employed for the other maize types grown in tropical, mid-altitude and highland maize production regions where, however, an important part of maize production is the use of landraces (traditional local maize varieties) and improved varieties for food preparations of preferred grain texture and colour.
BOTANY AND DISTRIBUTION
Cultivated maize is Zea mays L. (Species Plantarum 971. 1753) or Zea mays L. subsp. mays Iltis (Iltis and Doebley 1980), and two of its relatives, Tripsacum and Teosinte, are described later in this volume.
Email your librarian or administrator to recommend adding this to your organisation's collection.