Cytological Evidence that Alternative Transposition by Ac Elements Causes Reciprocal Translocations and Inversions in Zea mays L.

McClintock discovered the first transposable element system, the Ac/Ds system in maize. She also reported that the Ac/Ds system could cause chromosome breakage and chromosome aberrations; however, the underlying mechanism was not known. Here, we recovered reciprocal translocations and inversions that were produced by alternative transposition in maize lines containing closely linked Ac transposable element termini. The cytological breakpoints of 7 reciprocal translocations and 2 pericentric inversions were determined by cytological analysis in this study

Observed changes in surface atmospheric energy over land

The temperature of the surface atmosphere over land has been rising during recent decades. But surface temperature, or, more accurately, enthalpy which can be calculated from temperature, is only one component of the energy content of the surface atmosphere. The other parts include kinetic energy and latent heat. It has been advocated in certain quarters that ignoring additional terms somehow calls into question global surface temperature analyses. Examination of all three of these components of atmospheric energetics reveals a significant increase in global surface atmospheric energy since the 1970s. Kinetic energy has decreased but by over two orders of magnitude less than the increases in both enthalpy and latent heat which provide approximately equal contributions to the global increases in heat content. Regionally, the enthalpy or the latent heat component can dominate the change in heat content. Although generally changes in latent heat and enthalpy act in concert, in some regions they can have the opposite signs