Absorption of solar radiation by clouds: observations versus models.

There has been a long history of unexplained anomalous absorption of solar radiation by clouds. Collocated satellite and surface measurements of solar radiation at five geographically diverse locations showed significant solar absorption by clouds, resulting in about 25 watts per square meter more global-mean absorption by the cloudy atmosphere than predicted by theoretical models. It has often been suggested that tropospheric aerosols could increase cloud absorption. But these aerosols are temporally and spatially heterogeneous, whereas the observed cloud absorption is remarkably invariant with respect to season and location. Although its physical cause is unknown, enhanced cloud absorption substantially alters our understanding of the atmosphere's energy budget.

Renal gluconeogenesis in eviscerated diabetic rats.

Experiments were carried out in eviscerated rats having intact kidneys to examine the effects on body glucose of some conditions known to stimulate overall gluconeogenesis. Preliminary experiments confirmed the enhancing effect of renal ligation on falling blood glucose concentration after evisceration. Adrenodemedullation of alloxan-diabetic rats did not affect blood glucose concentration, but comparison with completely adrenalectomized rats again supported previous conclusions that the adrenocortical hormones, in the presence of the kidneys, maintained the blood glucose at higher concentrations after evisceration. Calculated changes in total body glucose concentration over a 4-hr period after evisceration of several groups of alloxan-diabetic rats with intact kidneys showed that epinephrine, like cortisol, consistently reduced losses of total body glucose compared to the controls. An intravenous infusion of lactic acid so diminished the fall in total body glucose in diabetic rats that changes actually became positive, which indicated a net addition of glucose to the body fluids. Thus, the increased rate of disappearance of blood glucose that follows renal ligation in eviscerated animals results in large part from the interruption of renal gluconeogenesis, and the kidneys as well as the liver must be taken into account when considering the total glucogenic capacity of the body.