7,764 research outputs found
Recent Trends in Resource Sharing Among the Poor
Motivated in part by the dramatic changes in the United States economy and public assistance policies, many researchers have examined the changes in the resources of the low-income population over the last two decades, with particular attention paid to income from earnings and public assistance programs. One source of income that has received comparatively little attention is income from private transfers. However, private transfers may be a key source of support for low-income individuals, especially for those who have had little attachment to the labor force or who have experienced reductions in public assistance. In this paper, we provide a conceptual discussion of private transfers drawing on several related literatures and provide new empirical evidence regarding the significance of private of transfers as a source income. We find that private transfers are an important source of income for many less-skilled households, the contribution of private transfers to total income has increased over time, and shared living arrangements are a common mechanism for providing assistance.
How Important Are Wages to the Elderly? Evidence from the New Beneficiary Data System and the Social Security Earnings Test
More than 40 percent of Social Security beneficiaries continue to work after age 65. This research investigates the extent to which these individuals substitute labor across periods in response to anticipated wage changes induced by the Social Security earnings test. While we find that a disproportionate number of individuals choose earnings within a few percentage points of the earnings limit, we find no evidence that these individuals substitute labor supply between
A hydrodynamic study of a fastâbed dual circulating fluidized bed for chemical looping combustion
This study explores the use of a dual interconnected circulating fluidized bed (CFB) for chemical looping combustion. This design can enhance gasâsolid interactions, but it is difficult to control the solid transfer and circulation rates. With the use of a 1:1 scale cold-flow model, an investigation determining the hydrodynamic behavior of the dual CFB system has been conducted. The cold-flow system consists of two identical fast-bed risers, each with an internal diameter of 100â
mm and a height of 7â
m. The simplified cold-flow model is based on the chemical looping Pilot-Scale Advanced CO2 Capture Technology (PACT) facility at Cranfield. Here, we have determined the minimum fluidization and transport velocities, and we have assessed the solid density profiles, transport capacity, and potential for the dilution by air/N2 leakage into the CO2 stream exiting the fuel reactor. The experimental procedure uses two different bed materials, molochite (ceramic clay) and FE100 (iron particles), and it satisfies the dynamic scaling laws to model the bed inventory within the system. The results indicate that the two fast-bed risers share similar density and pressure profiles. Stable circulation can be achieved through pneumatic transport. The circulation rate of the system is flexible and can be adjusted by altering the fluidization velocity in the riser and by altering the bed inventory. The gas leakage from the loop seal to the cyclone was found to be sensitive to the bed height and fluidization velocity in the loop seal. However, by maintaining a loop-seal bed height above 600â
mm during operation, the outlet stream remains undiluted
Composite vertices that lead to soft form factors
The momentum-space cut-off parameter of hadronic vertex functions
is studied in this paper. We use a composite model where we can measure the
contributions of intermediate particle propagations to . We show that
in many cases a composite vertex function has a much smaller cut-off than its
constituent vertices, particularly when light constituents such as pions are
present in the intermediate state. This suggests that composite
meson-baryon-baryon vertex functions are rather soft, i.e., they have \Lambda
considerably less than 1 GeV. We discuss the origin of this softening of form
factors as well as the implications of our findings on the modeling of nuclear
reactions.Comment: REVTex, 19 pages, 5 figs(to be provided on request
Unexplained Gaps and Oaxaca-Blinder Decompositions
We analyze four methods to measure unexplained gaps in mean outcomes: three decompositions based on the seminal work of Oaxaca (1973) and Blinder (1973) and an approach involving a seemingly naĂŻve regression that includes a group indicator variable. Our analysis yields two principal findings. We show that the coefficient on a group indicator variable from an OLS regression is an attractive approach for obtaining a single measure of the unexplained gap. We also show that a commonly-used pooling decomposition systematically overstates the contribution of observable characteristics to mean outcome differences when compared to OLS regression, therefore understating unexplained differences. We then provide three empirical examples that explore the practical importance of our analytic results.discrimination, decompositions
Econometric Studies of Long-Run Earnings Inequality: Dissertation Summary
My dissertation comprises three econometric studies of long-run earnings inequality. Two studies are empirical analyses of U.S. data, one contributing to the well-established literature on male earnings inequality and the other extending the analysis to the understudied level of families. These empirical chapters focus on documenting trends in long-run earnings inequality and evaluating the potential causes. The third study develops an econometric technique that is necessary to complete the empirical analyses, specifically, how to use a Generalized Method of Moments estimator with an incomplete data set. Because this estimator is becoming increasingly popular and because researchers often face the prospect of using incomplete data, the study will be useful to the applied researcher
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