〈報文〉リモートセンシング実験でみられた水理実験センターの圃場の草地植生の季節変化

As a step toward seasonal monitoring of vegetation development (phenology) from space, we investigated seasonal change of several biophysical properties (leaf area index [LAI], coverage of vegetation, chlorophyll density, canopy height, and C3/C4 composition) and some spectral vegetation indices (normalized difference vegetation index [NDVI] and red edge position [REP)) m an annual grassland. These biophysical properties changed in different ways with each other. In the growing period of grasses, coverage of vegetation was the first to achieve asymptotic maximum. LAI was the second, chlorophyll quantity was the third, and then canopy height was the latest to achieve its maximum. NDVI showed a similar behavior to vegetation coverage, rapidly increasing until early June. On the other hand, REP continued to increase from May until September with a temporal decrease in early May and a steady increase in August, which fairly corresponded to the behavior of leaf chlorophyll density. These characteristic seasonal change of the grassland should be useful knowledge for interpretation of land surface process of the grassland especially in use of remote-sensing. In this sense, multiple use of several kinds of optical quantities which can be captured by remote sensing might be usefu

What is artificial endocrine pancreas? Mechanism and history

The artificial endocrine pancreas is a feedback control instrument that regulates insulin delivery on a minute-by-minute basis according to measured blood glucose levels. Only one type of bedside-type artificial endocrine pancreas is now available in Japan: STG-22 (Nikkiso Co. Ltd., Japan). In the insulin infusion algorithm, insulin is infused on the basis of its proportional and derivative actions, to blood glucose concentrations with a constant time delay. The bedside-type artificial endocrine pancreas has been proven to be useful not only as a therapeutic tool for diabetes mellitus, but also as an elegant research tool for investigating the pathophysiology of the disease, by using the euglycemic hyperinsulinemic glucose clamp technique. The wearable type of closed-loop system has been developed recently. The breakthrough is the establishment of a needle-type glucose sensor. The development of closed-loop glycemic control systems that enable long-term physiological regulation has focused on implantable devices. Much effort has been expended to realize these devices