Macroeconomic Impacts of Aging in Japan on the Balance of Current Accounts

This paper investigates questions regarding the saving rates by age brackets and aggregate savings, and then conducts a simulation analysis of the current account, from the I-S balances of households, corporations and the government. Saving rates of the old (65 years old and above) with publicly available data are high because of a selection bias in household head, that excludes the old living with younger family members and being non-head of the household. The paper estimates the true saving rates by age brackets rather than of household head's age brackets with taking the non-head households' member into account. Estimated saving rates of the old are still positive (about 10% to 20% which are less than those of the young) even after adjusting for the bias. The impact of aging on the aggregate saving rates will not be large if the future old people continue to save as the current old people. We forecast the current account in several scenarios, using data of demographic changes, the estimated aggregate saving rates, and the estimated interest payments of government bonds. It is of our particular interest whether the current account will turn to be negative by the rapid demographic change. It is found that the IS balances would remain positive under a condition that the government bond issues would be constrained by fiscal sustainability.

Upper Lumbar Pedicle Screw Insertion Using Three-Dimensional Fluoroscopy Navigation:Assessment of Clinical Accuracy

We used a navigation system to insert 128 pedicle screws into 69 vertebrae (L1 to L3) of 49 consecutive patients. We assessed the pedicle isthmic width and the permission angle for pedicle screw insertion. The permission angle is the angle defined by the greatest medial and lateral trajectories allowable when placing the screw through the center of the pedicle. The rate of narrow-width pedicles (isthmic width less than 5mm) was 5 of 60 pedicles (8%) at L1, 4 of 60 pedicles (7%) at L2, and none (0%) at L3, L4 and L5. The rate of narrow-angle pedicles (a permission angle less than 15 degrees) was 21 of 60 pedicles (35%) at L1, 7 of 60 (12%) at L2, 3 of 60 (5%) at L3, and none (0%) at L4 and L5. Of 128 pedicle screws inserted into 69 vertebrae from L1 to L3, 125 (97.7%) were classified as Grade 1 (no pedicle perforation). In general, the upper lumbar vertebrae have more narrow-width and -angle pedicles. However, we could reduce the rate of pedicle screw misplacement in upper lumbar vertebra using a three-dimensional fluoroscopy and navigation system