Estimating a semi-parametric duration model without specifying heterogeneity

This paper presents a new estimator for the mixed proportional hazard model that allows for a nonparametric baseline hazard and time-varying regressors. In particular, this paper allows for discrete measurement of the durations as happens often in practice.

Use of Selected Available Technology To Provide Relatively Inexpensive Distance Learning Courses along the Texas/Mexico Border Corridor.

As the population of minority pupils continues to increase, the need for special education personnel to identify and educate culturally and linguistically diverse exceptional students will also rise. Continuing shortages of qualified personnel in special education have been declared a national emergency, with diagnostic staff ranked as the fourth highest area of need. Shortages are particularly severe along the Texas-Mexico border, where a 1997 needs assessment predicted a need for 41 diagnosticians, preferably bilingual, within the ensuing 5 years. This paper describes initial steps in the development of Project DEED (Distance Education for Educational Diagnosticians), a federally funded distance learning program to provide courses in special educational diagnostics to rural border communities far from higher education institutions. The closing of one of the four university-based special education programs in the south Texas border corridor exacerbated an already serious situation. At about the same time, T-1 fiber optic telephone lines were extended to all rural schools in the area. This, coupled with other technological advances, made it feasible to offer multimedia-based presentations accompanied by videoconferencing. Steps in program development included choosing software, establishing 8-10 distal sites, acquiring sufficient space to accommodate hardware and work space, building technological infrastructure, developing staff within a team approach model, keeping costs down, and selecting each distal-based cohort

THE FALLIBILITY OF THE BRANDENBURG TEST THROUGH THE LENS OF THE CAPITOL INSURRECTION

This Article explores the insurrection that occurred at our Capitol in relation to the Brandenburg test. The paper seeks to discuss whether free speech has gone too far, whether Brandenburg needs reform, and how we could effectuate such changes. While the Article certainly has political undertones, sincere efforts were made to present the facts in a more neutral fashion. Despite the political nature of the Article, I wholeheartedly believe that discussing the insurrection is critical to not only our nation’s history, but to the law

Entry in the ADHD drugs market: Welfare impact of generics and me-toos

Recent decades have seen a growth in treatments for attention deficit hyperactivity disorder (ADHD) including many branded and generic drugs. In the early 2000's, new drug entry dramatically altered market shares. We estimate a demand system for ADHD drugs and assess the welfare impact of new drugs. We find that entry induced large welfare gains by reducing prices of substitute drugs, and by providing alternative delivery mechanisms for existing molecules. Our results suggest that the success of follow-on patented drugs may come from unanticipated innovations like delivery mechanisms, a factor ignored by proposals to retard new follow-on drug approvals

Common Causes and The Direction of Causation

Is the common cause principle merely one of a set of useful heuristics for discovering causal relations, or is it rather a piece of heavy duty metaphysics, capable of grounding the direction of causation itself? Since the principle was introduced in Reichenbach’s groundbreaking work The Direction of Time (1956), there have been a series of attempts to pursue the latter program—to take the probabilistic relationships constitutive of the principle of the common cause and use them to ground the direction of causation. These attempts have not all explicitly appealed to the principle as originally formulated; it has also appeared in the guise of independence conditions, counterfactual overdetermination, and, in the causal modelling literature, as the causal markov condition. In this paper, I identify a set of difficulties for grounding the asymmetry of causation on the principle and its descendents. The first difficulty, concerning what I call the vertical placement of causation, consists of a tension between considerations that drive towards the macroscopic scale, and considerations that drive towards the microscopic scale—the worry is that these considerations cannot both be comfortably accommodated. The second difficulty consists of a novel potential counterexample to the principle based on the familiar Einstein Podolsky Rosen (EPR) cases in quantum mechanics

Determination of amino acids involved in specificity and activity of ChlaDUB2

Chlamydia trachomatis is a pathogen which infects humans as a sexually transmitted disease or through ocular infection, causing ocular trachoma. Ocular trachoma is the leading cause of non-congenital blindness in developing countries. The bacteria employs the deubiquitinating enzyme ChlaDUB2 to remove ubiquitin from its inclusion membrane in order to avoid lysosomal degradation. Key amino acids involved in ubiquitin recognition and cleavage were mutated in order to probe substrate specificity and catalytic activity of ChlaDUB2. Mutants were used in fluorometry assays in order to determine how the mutations affect the ability of ChlaDUB2 to release the amino methyl coumarin (AMC) group from ubiquitin-AMC. It was found that point mutants C282A, M190A, Q275A, L333A, and a deletion mutant in which a helix (VR3) was removed all reduced deubiquitinating activity. These results indicate that the mutated residues contribute to ubiquitin binding and hence catalysis. These results lead to a better understanding of the deubiquitinating activity of ChlaDUB2

Preference purification and the inner rational agent:A critique of the conventional wisdom of behavioural welfare economics

Neoclassical economics assumes that individuals have stable and context-independent preferences, and uses preference-satisfaction as a normative criterion. By calling this assumption into question, behavioural findings cause fundamental problems for normative economics. A common response to these problems is to treat deviations from conventional rational-choice theory as mistakes, and to try to reconstruct the preferences that individuals would have acted on, had they reasoned correctly. We argue that this preference purification approach implicitly uses a dualistic model of the human being, in which an inner rational agent is trapped in an outer psychological shell. This model is psychologically and philosophically problematic