Nonlinear Competition Between Small and Large Hexagonal Patterns

Recent experiments by Kudrolli, Pier and Gollub on surface waves, parametrically excited by two-frequency forcing, show a transition from a small hexagonal standing wave pattern to a triangular ``superlattice'' pattern. We show that generically the hexagons and the superlattice wave patterns bifurcate simultaneously from the flat surface state as the forcing amplitude is increased, and that the experimentally-observed transition can be described by considering a low-dimensional bifurcation problem. A number of predictions come out of this general analysis.Comment: 4 pages, RevTex, revised, to appear in Phys. Rev. Let

Movements of Gulf Sturgeon (Acipenser oxyrinchus desotoi) in Nearshore Habitat as Determined by Acoustic Telemetry

Gulf sturgeon were tagged with telemetry tags and were tracked and relocated in fall and early winter of 1996 and 1998 to determine migration patterns and winter feeding habitats after they emigrated from the Suwannee River, Florida, into the Gulf of Mexico. We hypothesized that their migration would generally follow the drowned Suwannee River channel across the West Florida shelf. Fish left the river in late Oct. or early Nov., about the time river water temperatures fell below 20 C. Tracked and relocated fish moved slowly and remained offshore of Suwannee Sound in nearby shallow (\u3c6 m) marine-estuarine habitats until at least mid or late Dec. The relatively small area (~115km2) within which fish were consistently relocated in 1998 probably is a critically important feeding habitat because adult Gulf sturgeon, which do not feed while in the river, occupy it for up to half their short (4-5 mo) marine residency. The fish left the area in late Dec. or early Jan., most likely in response to powerful cold front-generated weather conditions (under which, boat-based acoustic tracking is infeasible). A large (1,760 km2) adjacent area was searched for sonic-tagged sturgeon in early Jan. 1999, but only one was relocated (~50 km northwest of the Nov.-Dec. area). Although we were unable to address the hypothesis that their migration follows the Suwannee paleochannel, the results do indicate that Gulf sturgeon move to yet unknown, distant, late-winter feeding areas of the Gulf of Mexico before returning to the river in spring

The salience of sport in cross-race friendship selection

In response to growing racial concerns, stakeholders have called for programs that facilitate positive cross-race interactions. Adolescence has been targeted as the most effective life stage to initiate programs promoting relationships. Since schools are one of the primary social influences on adolescent development, they have been emphasized as a particularly important setting for promoting intergroup contact. Sport plays an important role in the experiences of students, and contributes to intergroup relations within a school. The purpose of this study is to examine the unique effect of sport participation on cross-race friendship selection. Using data from Wave I of The National Longitudinal Study of Adolescent Health (Add Health), mixed-effects regression models and analysis of variance (ANOVA) were used to assess the effects of sport participation on friendship heterogeneity. Overall, participation in sport activities did not significantly influence the racial heterogeneity of adolescent’s friendship networks

Comment on studying the corrections to factorization in B -> D(*) X

We propose studying the mechanism of factorization in exclusive decays of the form B->D(*)X by examining the differential decay rate as a function of the invariant mass of the light hadronic state X. If factorization works primarily due to the large N_c limit then its accuracy is not expected to decrease as the X invariant mass increases. However, if factorization is mostly a consequence of perturbative QCD then the corrections should grow with the X invariant mass. Combining data for hadronic tau decays and semileptonic B decays allows tests of factorization to be made for a variety of final states. We discuss the examples of B->D^*\pi^+\pi^-\pi^-\pi^0 and B->D^*\omega\pi^-. The mode B->D^*\omega\pi^- will allow a precision study of the dependence of the corrections to factorization on the invariant mass of the light hadronic state.Comment: 7 pages, minor clarifications to tex

Variation in Criminogenic Risks by Mental Health Symptom Severity: Implications for Mental Health Services and Research

Although a growing body of literature has demonstrated that justice-involved people with mental illnesses have criminogenic risk factors at similar or elevated rates as compared to justice-involved people without mental illnesses, more information about how criminogenic risks vary by intensity of mental health symptoms is needed. This information is particularly important for probation agencies who supervise the vast majority of justice-involved individuals with mental illnesses and who are increasingly implementing specialty mental health supervision approaches. To this end, this study examines the relationship between criminogenic risk and intensity of self-reported symptoms of mental illnesses among 201,905 individuals on probation from a large southeastern state. Self-report measures of symptoms of mental illnesses were categorized as low, moderate or high and criminogenic risks were compared among the following three groups: (1) those with no or low self-reported symptoms of mental illness; (2) those reporting moderate levels of symptoms; and (3) those reporting high or elevated levels of symptoms. Our findings suggest that the strength of relationships between symptoms of mental illnesses and criminogenic risks varies by type of criminogenic risk. Also, elevated symptoms of mental illness are associated with higher levels of criminogenic risks. More research about interventions that address mental illnesses and criminogenic risks is needed to inform practice and policy