The Labor Supply Effects of Disability Insurance Work Disincentives: Evidence from the Automatic Conversion to Retirement Benefits at Full Retirement Age

The Social Security Disability Insurance (DI) program imposes strong work restrictions on beneficiaries; however, the causal effect of the work disincentives on labor supply has been difficult to estimate. We take a new look at this question by exploiting the fact that DI benefits are payable only until full retirement age (FRA), at which point they are converted to retired worker benefits, and the program’s implicit high marginal tax rate on earnings is abruptly relaxed. Using a quasiexperimental research design, we examine whether the DI work disincentives are binding by comparing changes in labor force participation rates before and after the FRA for DI beneficiaries and non-beneficiaries. We find a relative increase in labor force participation at FRA for DI beneficiaries of 10.4 percentage points, and argue that this is likely a lower bound estimate on the labor supply disincentive effects of the DI program.

An Analysis of the Effects of Recent Social Security Reforms Using Aggregate and Public-Use Administrative Micro Data

In the last few years the United States Social Security Old Age Benefit system has undergone some of the most significant changes since its inception. We have seen in a short period of time the implementation of the phased increase in the Normal Retirement Age (NRA) with the resulting increase in the penalty for claiming benefits early, the elimination of the Earnings Test for those above the NRA, and the incremental increase in the Delayed Retirement Credit (DRC) for those claiming benefits after the NRA. Since these changes have taken place only recently, there is relatively little research using household level data analyzing the consequences of all these changes. Using aggregate data from the Social Security Administration and a Public Use Micro-Data extract from the Master Beneficiary Record we are able to uncover a number of interesting trends in benefit claiming behavior and level of benefits receipt, which can help us understand how the changes in the system are shaping the retirement benefits claiming behavior of Older Americans. We find significant effects of the removal of the earnings test and the increase in the NRA, but very small effects as a result of the increases in the DRC.Benítez-Silva acknowledges the financial support from Grant Number 5 P01 AG022481-04 from the National Institute on Aging, the MRRC and the Spanish Ministry of Science and Technology through project number SEJ2005-08783-C04-01, on related projects. Na Yin wants to thank the Center for Retirement Research at Boston College for their support on a related project.Peer reviewe

Injection method of barrier bucket supported by off-aligned electron cooling for CRing of HIAF

A new accelerator complex, HIAF (the High Intensity Heavy Ion Accelerator Facility), has been approved in China. It is designed to provide intense primary and radioactive ion beams for research in high energy density physics, nuclear physics, atomic physics as well as other applications. In order to achieve a high intensity of up to 5e11 ppp 238U34+, the Compression Ring (CRing) needs to stack more than 5 bunches transferred from the Booster Ring (BRing). However, the normal bucket to bucket injection scheme can only achieve an intensity gain of 2, so an injection method, fixed barrier bucket (BB) supported by electron cooling, is proposed. To suppress the severe space charge effect during the stacking process, off-alignment is adopted in the cooler to control the transverse emittance. In this paper, simulation and optimization with the BETACOOL program are presented

Neural Basis of Working Memory Enhancement after Acute Aerobic Exercise: fMRI Study of Preadolescent Children

Working memory lies at the core of cognitive function and plays a crucial role in children’s learning, reasoning, problem solving, and intellectual activity. Behavioral findings have suggested that acute aerobic exercise improves children’s working memory; however, there is still very little knowledge about whether a single session of aerobic exercise can alter working memory’s brain activation patterns, as assessed by functional magnetic resonance imaging (fMRI). Therefore, we investigated the effect of acute moderate-intensity aerobic exercise on working memory and its brain activation patterns in preadolescent children, and further explored the neural basis of acute aerobic exercise on working memory in these children. We used a within-subjects design with a counterbalanced order. Nine healthy, right-handed children were scanned with a Siemens MAGNETOM Trio 3.0 Tesla magnetic resonance imaging scanner while they performed a working memory task (N-back task), following a baseline session and a 30-min, moderate-intensity exercise session. Compared with the baseline session, acute moderate-intensity aerobic exercise benefitted performance in the N-back task, increasing brain activities of bilateral parietal cortices, left hippocampus, and the bilateral cerebellum. These data extend the current knowledge by indicating that acute aerobic exercise enhances children’s working memory, and the neural basis may be related to changes in the working memory’s brain activation patterns elicited by acute aerobic exercise

Finite iterative algorithms for solving generalized coupled Sylvester systems – Part I: One-sided and generalized coupled Sylvester matrix equations over generalized reflexive solutions

AbstractThe generalized coupled Sylvester systems play a fundamental role in wide applications in several areas, such as stability theory, control theory, perturbation analysis, and some other fields of pure and applied mathematics. The iterative method is an important way to solve the generalized coupled Sylvester systems. In this two-part article, finite iterative methods are proposed for solving one-sided (or two-sided) and generalized coupled Sylvester matrix equations and the corresponding optimal approximation problem over generalized reflexive solutions (or reflexive solutions). In part I, an iterative algorithm is constructed to solve one-sided and coupled Sylvester matrix equations (AY−ZB,CY−ZD)=(E,F) over generalized reflexive matrices Y and Z. When the matrix equations are consistent, for any initial generalized reflexive matrix pair [Y1,Z1], the generalized reflexive solutions can be obtained by the iterative algorithm within finite iterative steps in the absence of round-off errors, and the least Frobenius norm generalized reflexive solution pair can be obtained by choosing a special kind of initial matrix pair. The unique optimal approximation generalized reflexive solution pair [Y^,Z^] to a given matrix pair [Y0,Z0] in Frobenius norm can be derived by finding the least-norm generalized reflexive solution pair [Y∼∗,Z∼∗] of two new corresponding generalized coupled Sylvester matrix equations (AY∼-Z∼B,CY∼-Z∼D)=(E∼,F∼), where E∼=E-AY0+Z0B,F∼=F-CY0+Z0D. Several numerical examples are given to show the effectiveness of the presented iterative algorithm