Extinction in the Large Magellanic Cloud Bar around NGC 1854, NGC 1856, and NGC 1858

We report on the extinction properties in the fields around the clusters NGC 1854, NGC 1856, and NGC 1858 in the bar of the Large Magellanic Cloud. The color–magnitude diagrams of the stars in all these regions show an elongated red giant clump that reveals a variable amount of extinction across these fields, ranging from A V ≃ 0.2 to A V ≃ 1.9, including Galactic foreground extinction. The extinction properties nonetheless are remarkably uniform. The slope of the reddening vectors measured in the (V − I, V) and (B − I, B) color–magnitude planes is fully in line with the A V /E(B − V) ≃ 5.5 value found in the outskirts of 30 Dor. This indicates the presence of an additional gray extinction component in the optical requiring big grains to be about twice as abundant as in the diffuse Galactic interstellar medium (ISM). Areas of higher extinction appear to be systematically associated with regions of more intense star formation, as measured by the larger number of stars more massive than 8 M ⊙, thus making injection of big grains into the ISM by a SNII explosion the likely mechanism at the origin of the observed gray extinction component.

Systematic Review of Differential Reinforcement of Alternative Behavior Without Extinction for Individuals With Autism

The purpose of this article is to review the literature on differential reinforcement of alternative behavior procedures without extinction for individuals with autism. Using predetermined inclusion criteria, a total of 10 studies were included and summarized in terms of the following: (a) participant characteristics (e.g., sex, age, and diagnosis), (b) treatment setting, (c) problem behavior, (d) function, (e) alternative behavior, (f) intervention, (g) outcomes, and (h) conclusiveness of evidence. Of the 10 studies, nine demonstrated positive effects and one mixed effects. Five studies successfully reduced problem behavior by manipulating different reinforcement parameters (magnitude, immediacy, and quality) and four manipulated the schedule of reinforcement. One study had mixed results with two of the three participants requiring extinction. The findings of this review suggest that variations of differential reinforcement of alternative behavior interventions without an extinction component may be considered promising practices for the treatment of challenging behavior in individuals with autism.

Trait Evolution with Jumps: Illusionary Normality

ABSTRACTPhylogenetic comparative methods for real-valued traits usually make use of stochastic process whose trajectories are continuous. This is despite biological intuition that evolution is rather punctuated than gradual. On the other hand, there has been a number of recent proposals of evolutionary models with jump components. However, as we are only beginning to understand the behaviour of branching Ornstein–Uhlenbeck (OU) processes the asymptotics of branching OU processes with jumps is an even greater unknown. In this work we build up on a previous study concerning OU with jumps evolution on a pure birth tree. We introduce an extinction component and explore via simulations, its effects on the weak convergence of such a process. We furthermore, also use this work to illustrate the simulation and graphic generation possibilities of the mvSLOUCH package.

Behavioral Contrast in Pigeons with Qualitatively Different Reinforcers

Three white Carneaux pigeons were trained to respond on a mult VI 1-min. (milo reinforcement), VI 1-min. (pea reinforcement) schedule when each component was associated with a different key, feeder, and reinforcer. The experiment was divided into four phases. In Phases 1 and 3, baseline rates of responding were established. In experimental Phases 2 and 4, one component of the multiple schedule was changed to extinction. During the experimental phases, response rates decreased in the extinction component and increased in the unchanged component (positive behavioral contrast). The increase in responding in the unchanged component was greater when the more valued reinforcer was extinguished. These findings are very similar to those reported by Beninger and Kendall (1975) and extend the positive contrast effect to another species, pigeons.