Using Discontinuous Eligibility Rules to Identify the Effects of the Federal Medicaid Expansions on Low Income Children

Despite intensive scrutiny, the effects of Medicaid expansions on the health insurance status of low-income children remain controversial. We re-examine the effects of the two largest federally-mandated expansions which offered Medicaid coverage to low-income children in specific age ranges and birth cohorts. We use a regression discontinuity approach, comparing Medicaid enrollment, private insurance coverage, and overall insurance coverage on either side of the age limits of the laws. We conclude that the modest impacts of the expansions on health insurance coverage arose because of very low takeup rates of the newly available coverage, rather than from crowd-out of private insurance coverage.

Using Discontinuous Eligibility Rules to Identify the Effects of the Federal Medicaid Expansions on Low Income Children

This paper exploits the discrete nature of the eligibility criteria for two major federal expansions of Medicaid to measure the effects on Medicaid coverage, overall health insurance coverage, and the probability of visiting a doctor. The '100 percent' expansion, effective in 1991, extended Medicaid eligibility to children born after September 30, 1983 in families below the poverty line. We estimate that this law led to about a 10 percentage point rise in Medicaid coverage for children born just after the cutoff date, and a similar or slightly smaller rise in overall health insurance. It also increased the fraction of children in the newly eligible group with a doctor visit in the previous year. The '133 percent' expansion, effective in 1990, extended Medicaid to children under 6 in families with incomes below 133 percent of the poverty line. This law had relatively small effects on Medicaid coverage for children near the eligibility limits, and little or no effect on health insurance coverage.

Reactive Atom Plasma (RAP) figuring machine for meter class optical surfaces

A new surface figuring machine called Helios 1200 is presented in this paper. It is designed for the figuring of meter sized optical surfaces with form accuracy correction capability better than 20 nm rms within a reduced number of iterations. Unlike other large figuring facilities using energy beams, Helios 1200 operates a plasma torch at atmospheric pressure, offers a high material removal rate, and a relatively low running cost. This facility is ideal to process large optical components, lightweight optics, silicon based and difficult to machine materials, aspheric, and free form surfaces. Also, the surfaces processed by the reactive atom plasma (RAP) are easy to fine polish through hand conventional sub-aperture polishing techniques. These unique combined features lead to a new capability for the fabrication of optical components opening up novel design possibilities for optical engineers. The key technical features of this large RAP machine are fast figuring capabilities, non-contact material removal tool, the use of a near Gaussian footprint energy beam, and a proven tool path strategy for the management of the heat transfer. Helios 1200 complies with the European machine safety standard and can be used with different types of reactive gases using either fluorine or chlorine compounds. In this paper, first the need for large optical component is discussed. Then, the RAP facility is described: radio frequency R.F generator, plasma torch, and 3 axis computer numerically controlled motion system. Both the machine design and the performance of the RAP tool is assessed under specific production conditions and in the context of meter class mirror and lens fabrication

Increased association of telomerase with short telomeres in yeast

Telomere function is mediated by the assembly of a protein complex on an array of telomeric DNA (TG) repeats synthesized by the telomerase enzyme. Telomerase action at chromosome ends is finely tuned by the telomeric complex so that a constant average number of repeats is maintained. This is achieved through a negative feedback process that is sensitive to TG tract length, but whose underlying mechanism is unknown. We show that short telomeres, which are preferential substrates for telomerase, display increased association with the enzyme in the S phase of the cell cycle, when telomerase acts. In addition, we provide support for a molecular mechanism by which this key step of telomerase recruitment is regulated by TG tract length

The Measurement of Medicaid Coverage in the SIPP : Evidence from a Comparison of Matched Records

This paper studies the accuracy of reported Medicaid coverage in the Survey of Income and Program Participation (SIPP) using a unique data set formed by matching SIPP survey responses to administrative records from the State of California. Overall, we estimate that the SIPP underestimates Medicaid coverage in the California population by about 10 percent. The probability that a SIPP respondent who is covered by Medicaid in a given month correctly reports their coverage is around 85 percent. The corresponding probability for low-income children is higher – around 90 percent. Under-reporting by those who are actually in the Medicaid system is partially offset by over-reporting of coverage by people who are not. Some of these false positive responses are attributable to errors and missing data in the administrative system, rather than to problems in the SIPP. Taking account of these errors, the estimated false positive rate for the population as a whole is about 1.5 percent, and 4-5 percent for poor children.

Regulation of telomere addition at DNA double-strand breaks

Telomeres constitute the ends of linear eukaryotic chromosomes. Due to the conventional mode of DNA replication, telomeric DNA erodes at each cell division. To counteract this, a specialized reverse transcriptase, telomerase, can elongate chromosome ends to maintain them at a constant average length. Because of their similarity to DNA double-strand breaks (DSBs), telomeres might be expected to induce a DNA damage response, which would lead to repair reactions and the generation of translocations or fusions. Many proteins present at telomeres prevent this by protecting (capping) the chromosome termini. Conversely, a DSB occurring in other regions of the genome, due, for instance, to a stalled replication fork or genotoxic agents, must be repaired by homologous recombination or end-joining to ensure genome stability. Interestingly, telomerase is able to generate a telomere de novo at an accidental DSB, with potentially lethal consequences in haploid cells and, at a minimum, loss of heterozygosity (LOH) in diploid cells. Recent data suggest that telomerase is systematically recruited to DSBs but is prevented from acting in the absence of a minimal stretch of flanking telomere-repeat sequences. In this review, we will focus on the mechanisms that regulate telomere addition to DSB

The Measurement of Medicaid Coverage in the SIPP: Evidence from California, 1990-1996

This paper studies the accuracy of reported Medicaid coverage in the Survey of Income and Program Participation (SIPP) using a unique data set formed by matching SIPP survey responses to administrative records from the State of California. Overall, we estimate that the SIPP underestimates Medicaid coverage in the California population by about 10 percent. Among SIPP respondents who can be matched to administrative records, we estimate that the probability someone reports Medicaid coverage in a month when they are actually covered is around 85 percent. The corresponding probability for low-income children is even higher - at least 90 percent. These estimates suggest that the SIPP provides reasonably accurate coverage reports for those who are actually in the Medicaid system. On the other hand, our estimate of the false positive rate (the rate of reported coverage for those who are not covered in the administrative records) is relatively high: 2.5 percent for the sample as a whole, and up to 20 percent for poor children. Some of this is due to errors in the recording of Social Security numbers in the administrative system, rather than to problems in the SIPP.

On the jumps of degrees below an recursively enumerable degree

We consider the set of jumps below a Turing degree, given by JB(a) = {x(1) : x <= a}, with a focus on the problem: Which recursively enumerable (r.e.) degrees a are uniquely determined by JB(a)? Initially, this is motivated as a strategy to solve the rigidity problem for the partial order R of r.e. degrees. Namely, we show that if every high(2) r.e. degree a is determined by JB(a), then R cannot have a nontrivial automorphism. We then defeat the strategy-at least in the form presented-by constructing pairs a(0), a(1) of distinct r.e. degrees such that JB(a(0)) = JB(a(1)) within any possible jump class {x : x' = c}. We give some extensions of the construction and suggest ways to salvage the attack on rigidity