The Causes and Consequences of Distinctively Black Names

In the 1960's, Blacks and Whites chose relatively similar first names for their children. Over a short period of time in the early 1970's, that pattern changed dramatically with most Blacks (particularly those living in racially isolated neighborhoods) adopting increasingly distinctive names, but a subset of Blacks actually moving toward more assimilating names. The patterns in the data appear most consistent with a model in which the rise of the Black Power movement influenced how Blacks perceived their identities. Among Blacks born in the last two decades, names provide a strong signal of socio-economic status, which was not previously the case. We find, however, no negative causal impact of having a distinctively Black name on life outcomes. Although that result is seemingly in conflict with previous audit studies involving resumes, we argue that the two sets of findings can be reconciled.

Testing for Racial Differences in the Mental Ability of Young Children

On tests of intelligence, Blacks systematically score worse than Whites, whereas Asians frequently outperform Whites. Some have argued that genetic differences across races account for the gap. Using a newly available nationally representative data set that includes a test of mental function for children aged eight to twelve months, we find only minor racial differences in test outcomes (0.06 standard deviation units in the raw data) between Blacks and Whites that disappear with the inclusion of a limited set of controls. The only statistically significant racial difference is that Asian children score slightly worse than those of other races. To the extent that there are any genetically-driven racial differences in intelligence, these gaps must either emerge after the age of one, or operate along dimensions not captured by this early test of mental cognition.

Formal proof of the AVM-1 microprocessor using the concept of generic interpreters

A microprocessor designated AVM-1 was designed to demonstrate the use of generic interpreters in verifying hierarchically decomposed microprocessor specifications. This report is intended to document the high-order language (HOL) code verifying AVM-1. The organization of the proof is discussed and some technical details concerning the execution of the proof scripts in HOL are presented. The proof scripts used to verify AVM-1 are also presented

Hatred and Profits: Getting Under the Hood of the Ku Klux Klan

The Ku Klux Klan reached its heyday in the mid-1920s, claiming millions of members. In this paper, we analyze the 1920s Klan, those who joined it, and the social and political impact that it had. We utilize a wide range of newly discovered data sources including information from Klan membership roles, applications, robe-order forms, an internal audit of the Klan by Ernst and Ernst, and a census that the Klan conducted after an internal scandal. Combining these sources with data from the 1920 and 1930 U.S. Censuses, we find that individuals who joined the Klan were better educated and more likely to hold professional jobs than the typical American. Surprisingly, we find few tangible social or political impacts of the Klan. There is little evidence that the Klan had an effect on black or foreign born residential mobility, or on lynching patterns. Historians have argued that the Klan was successful in getting candidates they favored elected. Statistical analysis, however, suggests that any direct impact of the Klan was likely to be small. Furthermore, those who were elected had little discernible effect on legislation passed. Rather than a terrorist organization, the 1920s Klan is best described as a social organization built through a wildly successful pyramid scheme fueled by an army of highly-incentivized sales agents selling hatred, religious intolerance, and fraternity in a time and place where there was tremendous demand.

Understanding the Black-White Test Score Gap in the First Two Years of School

In previous research, a substantial gap in test scores between White and Black students persists, even after controlling for a wide range of observable characteristics. Using a newly available data set (Early Childhood Longitudinal Study), we demonstrate that in stark contrast to earlier studies, the Black-White test score gap among incoming kindergartners disappears when we control for a small number of covariates. Over the first two years of school, however, Blacks lose substantial ground relative to other races. There is suggestive evidence that differences in school quality may be an important part of the explanation. None of the other hypotheses we test to explain why Blacks are losing ground receive any empirical backing. The difference between our findings and previous research is consistent with real gains made by recent cohorts of Blacks, although other explanations are also possible.

The formal verification of generic interpreters

The task assignment 3 of the design and validation of digital flight control systems suitable for fly-by-wire applications is studied. Task 3 is associated with formal verification of embedded systems. In particular, results are presented that provide a methodological approach to microprocessor verification. A hierarchical decomposition strategy for specifying microprocessors is also presented. A theory of generic interpreters is presented that can be used to model microprocessor behavior. The generic interpreter theory abstracts away the details of instruction functionality, leaving a general model of what an interpreter does

Tree-irreducible automorphisms of free groups

We introduce a new class of automorphisms $\varphi$ of the non-abelian free group $F_N$ of finite rank $N \geq 2$ which contains all iwips (= fully irreducible automorphisms), but also any automorphism induced by a pseudo-Anosov homeomorphism of a surface with arbitrary many boundary components. More generally, there may be subgroups of $F_N$ of rank $\geq 2$ on which $\varphi$ restricts to the identity. We prove some basic facts about such {\em tree-irreducible} automorphisms, and show that, together with Dehn twist automorphisms, they are the natural basic building blocks from which any automorphism of \FN can be constructed in a train track set-up. We then show: {\bf Theorem:} {\it Every tree-irreducible automorphism of $F_N$ has induced North-South dynamics on the Thurston compactification $\bar{\rm CV}_N$ of Outer space.} Finally, we define a "blow-up" construction on the vertices of a train track map, which, starting from iwips, produces tree-irreducible automorphisms which in general are not iwip

Towards composition of verified hardware devices

Computers are being used where no affordable level of testing is adequate. Safety and life critical systems must find a replacement for exhaustive testing to guarantee their correctness. Through a mathematical proof, hardware verification research has focused on device verification and has largely ignored system composition verification. To address these deficiencies, we examine how the current hardware verification methodology can be extended to verify complete systems

PKQuest: volatile solutes – application to enflurane, nitrous oxide, halothane, methoxyflurane and toluene pharmacokinetics

BACKGROUND: The application of physiologically based pharmacokinetic models (PBPK) to human studies has been limited by the lack of the detailed organ information that is required for this analysis. PKQuest is a new generic PBPK that is designed to avoid this problem by using a set of "standard human" default parameters that are applicable to most solutes. RESULTS: PKQuest is used to model the human pharmacokinetics of the volatile solutes. A "standard human" value for the lipid content of the blood and each organ (klip) was chosen. This set of klip and the oil/water partition coefficient then specifies the organ/blood partition for each organ. Using this approach, the pharmacokinetics of inert volatile solute is completely specified by just 2 parameters: the water/air and oil/water partition coefficients. The model predictions of PKQuest were in good agreement with the experimental data for the inert solutes enflurane and nitrous oxide and the metabolized solutes halothane and toluene. METHODS: The experimental data that was modeled was taken from previous publications. CONCLUSIONS: This approach greatly increases the predictive power of the PBPK. For inert volatile solutes the pharmacokinetics are determined just from the water/air and oil/water partition coefficient. Methoxyflurane cannot be modeled by this PBPK because the arterial and end tidal partial pressures are not equal (as assumed in the PBPK). This inequality results from the "washin-washout" artifact in the large airways that is established for solutes with large water/air partition coefficients. PKQuest and the worked examples are available on the web

PKQuest: measurement of intestinal absorption and first pass metabolism – application to human ethanol pharmacokinetics

BACKGROUND: PKQuest, a new physiologically based pharmacokinetic (PBPK) program, is applied to human ethanol data. The classical definition of first pass metabolism (FPM) based on the differences in the area under the curve (AUC) for identical intravenous and oral doses is invalid if the metabolism is non-linear (e.g. ethanol). Uncertainties in the measurement of FPM have led to controversy about the magnitude of gastric alcohol metabolism. PKQuest implements a new, rigorous definition of FPM based on finding the equivalent intravenous input function that would produce a blood time course identical to that observed for the oral intake. This input function equals the peripheral availability (PA) and the FPM is defined by: FPM = Total oral dose – PA. PKQuest also provides a quantitative measurement of the time course of intestinal absorption. METHODS: PKQuest was applied to previously published ethanol pharmacokinetic data. RESULTS: The rate of ethanol absorption is primarily limited by the rate of gastric emptying. For oral ethanol with a meal: absorption is slow (≈ 3 hours) and the fractional PKQuest FPM was 36% (0.15 gm/Kg dose) and 7% (0.3 gm/Kg). In contrast, fasting oral ethanol absorption is fast (≈ 50 minutes) and FPM is small. CONCLUSIONS: The standard AUC and one compartment methods significantly overestimate the FPM. Gastric ethanol metabolism is not significant. Ingestion of a coincident meal with the ethanol can reduce the peak blood level by about 4 fold at low doses. PKQuest and all the examples are freely available on the web at