Exploring the stigma of food stamps

This paper reports on theoretical research into the effect of stigma and social norms on policy outcomes of the Food Stamp program, in particular the effect on the caseload. As a general rule, it is impossible to predict whether norms will amplify or dampen the response of caseloads to any given policy intervention. Sometimes they have an effect, sometimes they do not. Much depends on whether the norms themselves change very much in response to policy changes. Social feedback (each norm violation encourages more violations) makes policy predictions uncertain. It can translate very small shocks into very large changes in the caseload. Norm systems can collapse abruptly. Norms can alleviate administrative problems involving targeting, since norms can define "true need" in a social sense and allow all of the truly needy to claim benefits. Eligible nonparticipants are viewed as "not needy" in the social sense, though they may be needy according to objective criteria. Norms may also lessen a program's incentive effects (against work, for example). Norms may exacerbate administrative problems involving resource availability. To the extent that program eligibility differs from socially defined need, the program will be unpopular. Norms also add considerable uncertainty to the environment of policy planning and execution. Policymakers who hope to reduce the influence of stigma on program resources and administration should consider localizing program eligibility rules, so that the rules correspond more closely to social definitions of need. Intense, broad-based local outreach efforts may also reduce stigma's power.

Fibrational induction rules for initial algebras

This paper provides an induction rule that can be used to prove properties of data structures whose types are inductive, i.e., are carriers of initial algebras of functors. Our results are semantic in nature and are inspired by Hermida and Jacobs’ elegant algebraic formulation of induction for polynomial data types. Our contribution is to derive, under slightly different assumptions, an induction rule that is generic over all inductive types, polynomial or not. Our induction rule is generic over the kinds of properties to be proved as well: like Hermida and Jacobs, we work in a general fibrational setting and so can accommodate very general notions of properties on inductive types rather than just those of particular syntactic forms. We establish the correctness of our generic induction rule by reducing induction to iteration. We show how our rule can be instantiated to give induction rules for the data types of rose trees, finite hereditary sets, and hyperfunctions. The former lies outside the scope of Hermida and Jacobs’ work because it is not polynomial; as far as we are aware, no induction rules have been known to exist for the latter two in a general fibrational framework. Our instantiation for hyperfunctions underscores the value of working in the general fibrational setting since this data type cannot be interpreted as a set

Can lay-led walking programmes increase physical activity in middle aged adults? : a randomised controlled trial

Study objective: To compare health walks, a community based lay-led walking scheme versus advice only on physical activity and cardiovascular health status in middle aged adults. Design: Randomised controlled trial with one year follow up. Physical activity was measured by questionnaire. Other measures included attitudes to exercise, body mass index, cholesterol, aerobic capacity, and blood pressure. Setting: Primary care and community. Participants: 260 men and women aged 40–70 years, taking less than 120 minutes of moderate intensity activity per week. Main results: Seventy three per cent of people completed the trial. Of these, the proportion increasing their activity above 120 minutes of moderate intensity activity per week was 22.6% in the advice only and 35.7% in the health walks group at 12 months (between group difference =13% (95% CI 0.003% to 25.9%) p=0.05). Intention to treat analysis, using the last known value for missing cases, demonstrated smaller differences between the groups (between group difference =6% (95% CI -5% to 16.4%)) with the trend in favour of health walks. There were improvements in the total time spent and number of occasions of moderate intensity activity, and aerobic capacity, but no statistically significant differences between the groups. Other cardiovascular risk factors remained unchanged. Conclusions: There were no significant between group differences in self reported physical activity at 12 month follow up when the analysis was by intention to treat. In people who completed the trial, health walks was more effective than giving advice only in increasing moderate intensity activity above 120 minutes per week

Detecting Bimodality in Astronomical Datasets

We discuss statistical techniques for detecting and quantifying bimodality in astronomical datasets. We concentrate on the KMM algorithm, which estimates the statistical significance of bimodality in such datasets and objectively partitions data into sub-populations. By simulating bimodal distributions with a range of properties we investigate the sensitivity of KMM to datasets with varying characteristics. Our results facilitate the planning of optimal observing strategies for systems where bimodality is suspected. Mixture-modeling algorithms similar to the KMM algorithm have been used in previous studies to partition the stellar population of the Milky Way into subsystems. We illustrate the broad applicability of KMM by analysing published data on globular cluster metallicity distributions, velocity distributions of galaxies in clusters, and burst durations of gamma-ray sources. PostScript versions of the tables and figures, as well as FORTRAN code for KMM and instructions for its use, are available by anonymous ftp from kula.phsx.ukans.edu.Comment: 32 page

Fluid Elasticity Can Enable Propulsion at Low Reynolds Number

Conventionally, a microscopic particle that performs a reciprocal stroke cannot move through its environment. This is because at small scales, the response of simple Newtonian fluids is purely viscous and flows are time-reversible. We show that by contrast, fluid elasticity enables propulsion by reciprocal forcing that is otherwise impossible. We present experiments on rigid objects actuated reciprocally in viscous fluids, demonstrating for the first time a purely elastic propulsion set by the object's shape and boundary conditions. We describe two different artificial "swimmers" that experimentally realize this principle.Comment: 5 pages, 4 figure

“Where Did I Learn That?” Exploring The Similarity Effect and Children’s Use of Memory Cues for Source Monitoring

An individual’s ability to accurately monitor source (attribute known or remembered information to its particular source or origin) develops gradually throughout childhood. Along with task difficulty (i.e., delay between encoding and retrieval), source similarity is among the utmost hindrance to individuals’ ability to accurately monitor source; specifically, the greater the similarity between sources the more difficult source monitoring judgments have been found to be, and the smaller similarity between sources (i.e., the greater number of differences between sources) the more accurate source monitoring judgments have been found to be. The similarity effect has been said to apply to all age groups, and has been assumed to be especially detrimental for young children. The present research looks further into the issue of source similarity, and suggests that the similarity effect may not be as generalizable as claimed. Specifically, although adults benefit most from dissimilar sources (as the similarity effect predicts), what may be paramount for young children (rather than more differences between sources) are few (at least one) but distinct differences between sources. The present study aims to begin consideration in this area by focusing on visual information. An experimental research design was used to assign 99 participants of different age groups (3-5, 6-8, 18-21) each to two different source-monitoring conditions. Each condition contained two actors, and the number of visual cues that differed between actors varied for each of the conditions (one-cue and five-cues). Specifically, the number of visual cues was manipulated such that one pair of actors displayed one distinct visual difference, and the other pair displayed five visual differences. After a short distractor task, participants were interviewed and asked to make source-monitoring judgments about actions performed by the actors within each of the two events. Data were collapsed and analyzed by age group. In line with past literature, an overall/general developmental progression was found to exist in participants’ ability to make accurate source judgments. Contrary to the present proposed theory, there was no significant interaction between age and cue condition; individuals of all age groups were found to be more accurate in the five-cue condition than in the one-cue condition (as predicted by the similarity effect). The obtained results in relation to the proposed theory were discussed. Understanding the way that individuals use cues to monitor source can help us further understand developmental differences in source monitoring, clarify the basic mechanisms involved, and highlight other aspects of children’s memory development. In addition, basic research questions concerning the nature of children’s source-monitoring errors may be particularly important to understanding the caveats surrounding forensic interviews with young children

The George Arents Library Award: A Recollection

Thomas E. Bird relates his submission for the George Arents Library Award in 1955, which recognized the student with the best personal library. Bird had a personal library containing over 500 Russian history titles. He received a medal designed by famous Syracuse University professor and scultor Ivan Mestrovic, and which was inscribed by professor and poet A.E. Johnson