Effects of signaled and unsignaled alternative reinforcement on persistence and relapse in children and pigeons

Three experiments explored the impact of different reinforcer rates for alternative behavior (DRA) on the suppression and post‐DRA relapse of target behavior, and the persistence of alternative behavior. All experiments arranged baseline, intervention with extinction of target behavior concurrently with DRA, and post‐treatment tests of resurgence or reinstatement, in two‐ or three‐component multiple schedules. Experiment 1, with pigeons, arranged high or low baseline reinforcer rates; both rich and lean DRA schedules reduced target behavior to low levels. When DRA was discontinued, the magnitude of relapse depended on both baseline reinforcer rate and the rate of DRA. Experiment 2, with children exhibiting problem behaviors, arranged an intermediate baseline reinforcer rate and rich or lean signaled DRA. During treatment, both rich and lean DRA rapidly reduced problem behavior to low levels, but post‐treatment relapse was generally greater in the DRA‐rich than the DRA‐lean component. Experiment 3, with pigeons, repeated the low‐baseline condition of Experiment 1 with signaled DRA as in Experiment 2. Target behavior decreased to intermediate levels in both DRA‐rich and DRA‐lean components. Relapse, when it occurred, was directly related to DRA reinforcer rate as in Experiment 2. The post‐treatment persistence of alternative behavior was greater in the DRA‐rich component in Experiment 1, whereas it was the same or greater in the signaled‐DRA‐lean component in Experiments 2 and 3. Thus, infrequent signaled DRA may be optimal for effective clinical treatment.     

SEARCHING FOR ANOTHER EARTH: THE RECENT HISTORY OF THE DISCOVERY OF EXOPLANETS

The discovery of exoplanets is a small part of the array of scientific arguments for and against the existence of extraterrestrial intelligence. Yet the recent stunning achievement of this program of observational astronomy has had a significant effect on scientific opinion and public interest. It also raises some key theological questions. New observing techniques are leading to the discovery of extrasolar planets daily. Earth‐like planets outside of our Solar System can now be identified and in future years explored for signs of life. This article maps the history of these discoveries and highlights some of the theological issues which are important to bring into dialogue with these scientific insights.     

ENFOLDING VIOLENCE,UNFOLDING HOPE: EMERGING CLOUDS OF POSSIBILITY FOR WOMEN IN ROMAN CATHOLICISM

In an effort to think through possible impossibilities, and enfold current problems within Catholicism into the luminous darkness of the cloud of the im/possible, this response to Catherine Keller's Cloud of the Impossible considers what might happen should Keller's cloud of mindful unknowing and nonseparable difference billow over and through one particular Catholic conundrum: how to respond to the terrifying reality of domestic violence in the context of a marriage defined as indissoluble, imperishable—inescapable.     

Reversible phase transition in vanadium oxide films sputtered on metal substrates

Vanadium oxide films, deposited on aluminium (Al), titanium (Ti) and tantalum (Ta) metal substrates by pulsed RF magnetron sputtering at a working pressure of 1.5 x10^?2 mbar at room temperature are found to display mixed crystalline vanadium oxide phases viz., VO₂, V₂O₃, V₂O₅. The films have been characterized by field-emission scanning electron microscopy, X-ray diffraction, differential scanning calorimetry (DSC) and X-ray photoelectron spectroscopy, and their thermo-optical and electrical properties have been investigated. Studies of the deposited films by DSC have revealed a reversible-phase transition found in the temperature range of 45–49 °C.