Social indicators and the study of inequality - commentary

Economic indicators ; Public policy ; Income distribution ; New York (N.Y.)

Welfare reform and New York City's low-income population

Welfare ; Poverty

The Decline in Welfare Receipt in New York City: Push vs. Pull

To evaluate the initial effects of welfare reform in New York City, we use the Current Population Survey to compare benefit receipt, earnings, and income among vulnerable households in 1994-95 and 1997-99. Overall, there were drops in public assistance and Food Stamps receipt, but the proportion getting Medicaid remained stable. Citizens and noncitizens lost welfare at similar rates, but the decline was significantly greater for Hispanic households than blacks, and was greatest among Puerto Ricans. Both the proportion with earnings and average earnings rose for Hispanics, but earnings did not increase for vulnerable blacks and whites. The sharp difference between Hispanics and blacks resulted in the convergence of Hispanics' higher welfare rates and lower incomes toward those of blacks. This convergence represents both the "pull" of a tighter labor market, together with improvements in Hispanics' education levels and shifts in family structure, and "push" of tighter administrative procedures.Assistance; Food Stamp; Medicaid; Public Assistance; Welfare

Xenon fluorides show potential as fluorinating agents

Xenon fluorides permit the controlled addition of fluorine across an olefinic double bond. They provide a series of fluorinating agents that permit ready separation from the product at a high purity. The reactions may be carried out in the vapor phase

Folding and insertion thermodynamics of the transmembrane WALP peptide

The anchor of most integral membrane proteins consists of one or several helices spanning the lipid bilayer. The WALP peptide, GWW(LA)$_n$(L)WWA, is a common model helix to study the fundamentals of protein insertion and folding, as well as helix-helix association in the membrane. Its structural properties have been illuminated in a large number of experimental and simulation studies. In this combined coarse-grained and atomistic simulation study, we probe the thermodynamics of a single WALP peptide, focusing on both the insertion across the water-membrane interface, as well as folding in both water and a membrane. The potential of mean force characterizing the peptide's insertion into the membrane shows qualitatively similar behavior across peptides and three force fields. However, the Martini force field exhibits a pronounced secondary minimum for an adsorbed interfacial state, which may even become the global minimum---in contrast to both atomistic simulations and the alternative PLUM force field. Even though the two coarse-grained models reproduce the free energy of insertion of individual amino acids side chains, they both underestimate its corresponding value for the full peptide (as compared with atomistic simulations), hinting at cooperative physics beyond the residue level. Folding of WALP in the two environments indicates the helix as the most stable structure, though with different relative stabilities and chain-length dependence.Comment: 12 pages, 5 figure

On the max-semistable limit of maxima of stationary sequences with missing values

Let [X(n)] be a stationary sequence with marginal distribution in the domain of attraction of a max-semistable distribution. This includes all distributions in the domain of attraction of any max-stable distribution and also other distributions like some integer-valued distributions with exponential type tails such as the Negative Binomial case. We consider the effect of missing values on the distribution of the maximum term. The pattern Of Occurrence of the missing values must be either iid or strongly mixing. We obtain the expression of the extremal index for the resulting sequence. The results generalize and extend the ones obtained for the max-stable domain of attraction. (c) 2008 Elsevier B.V. All rights reserved

A Pediatrics-Based Instrument for Assessing Resident Education in Evidence-Based Practice

Objective:The principles of evidence-based practice (EBP) are a mandated component of the pediatric residency curriculum; however, a pediatrics-based assessment tool validated with pediatric residents does not exist. Methods: We designed an assessment instrument composed of items in 4 categories: 1) demographics; 2) comfort level; 3) self-reported practice of EBP; and 4) EBP knowledge. This last section required participants to identify best evidence and most appropriate study design by using pediatric-based scenarios, develop searchable questions, and use existing published research to address diagnostic and treatment issues. Four groups completed the instrument: preclinical medical students (MS-2), incoming pediatric interns (PGY-1), incoming second- and third-year pediatric residents (PGY2-3), and expert tutors (expert). We determined internal consistency, interrater reliability, content validity, item difficulty, and construct validity. Results: Fifty-six subjects completed tests (MS-2, n = 13; PGY-1, n = 13; PGY2-3, n = 22; expert, n = 8). Internal reliability was good, with Cronbach's alpha = .80. Interrater reliability was high (kappa = 0.94). Items were free of floor or ceiling effects. Comfort level and self-reported practice of EBP increased with expertise level and prior EBP experience (P < .01). Scores on the knowledge section (out of 50 +/- SD) rose with training level (MS-2: 14.8 +/- 5.7; PGY-1: 22.2 +/- 3.4; PGY2-3: 31.7 +/- 6.1; experts: 43 +/- 4.0; P < .01). Scores also correlated with prior EBP education. Conclusions: We have developed a reliable and valid instrument to assess knowledge and skill in EBP taught to pediatric residents. This instrument can aid pediatric educators in monitoring the impact of the EBP curriculum

ADR Comes of Age: What Can We Expect in the Future?

Important developments in dispute resolution are reported in the legal and popular press every day. We have recently seen, for example, major developments in arbitration ethics, mediator confidentiality, standards for mandatory consumer predispute processes and expansion of court-annexed ADR programs. This is an opportune time to think about the future of ADR, because dispute resolution has survived its infancy and its sometimes awkward adolescence without any obvious body piercings, tattoos or felony convictions and is now thriving, energetic and poised for its most productive period

Bias in parametric estimation: reduction and useful side-effects

The bias of an estimator is defined as the difference of its expected value from the parameter to be estimated, where the expectation is with respect to the model. Loosely speaking, small bias reflects the desire that if an experiment is repeated indefinitely then the average of all the resultant estimates will be close to the parameter value that is estimated. The current paper is a review of the still-expanding repository of methods that have been developed to reduce bias in the estimation of parametric models. The review provides a unifying framework where all those methods are seen as attempts to approximate the solution of a simple estimating equation. Of particular focus is the maximum likelihood estimator, which despite being asymptotically unbiased under the usual regularity conditions, has finite-sample bias that can result in significant loss of performance of standard inferential procedures. An informal comparison of the methods is made revealing some useful practical side-effects in the estimation of popular models in practice including: i) shrinkage of the estimators in binomial and multinomial regression models that guarantees finiteness even in cases of data separation where the maximum likelihood estimator is infinite, and ii) inferential benefits for models that require the estimation of dispersion or precision parameters