It is commonly accepted that instrumental responses that have been extinguished can return. For example, in a phenomenon known as the renewal effect, extinguished behaviors return upon removal from the extinction context. Another well-accepted notion is that instrumental behaviors can be thought of as goal-directed actions, which form over the course of moderate amounts of practice or training, and habits, which form after extended practice. Despite years of research on both topics, what happens to actions and habits following extinction is poorly understood. The present experiments examined the renewal of actions and habits following retroactive interference paradigms such as extinction and additional training. Experiment 1 examined renewal of an action following its extinction in a separate context, and demonstrated that the extinguished behavior renewed as an action upon return to the acquisition context. Experiment 2 asked the same question about habits, and found that the behavior renewed as a habit after extinction upon return to the acquisition context. Experiment 3 examined renewal of goal-directed responding in one context following extensive training and conversion into habit in another context. It demonstrated that a single response could manifest as a habit in one context, and renew as an action in the original training context. Experiment 4 asked if this effect depends on returning to the acquisition context, or simply removal from the habit training context. The results suggest that mere removal from the habit training context is sufficient to renew the goal-directed properties of a behavior. Together, the results suggest that actions and habits can be inhibited in a context-specific manner by extinction, and that instrumental behaviors can have both action and habit properties that can each renew under the proper circumstances. The results also expand on the notion that habits are especially context specific, while actions can transfer across contexts.

The origin of marine biodiversity in the Indo-Pacific is poorly known. Faunal turnover in scleractinian reef corals has been hypothesised over the Miocene-Pliocene boundary (~5 Ma), in the Malay Archipelago. However, there is little information available on origination and extinction events in reef corals during the same period for the broader Indo-Pacific region. This is important because many species probably had a wider distribution than previously thought, and many more genera than has previously been estimated were probably present in the Indo-Pacific during the Neogene. Here I begin to fill the gap in our knowledge by reporting on the taxonomic composition and diversity of Neogene reef coral communities sampled from Indonesia (Salayar), Papua New Guinea (New Britain), and Fiji (Vanua Balavu). Sampling locations were chosen on their reported age, fossil content and preservation quality. Ages were refined using foraminiferal assemblages and Strontium 87/86 isotope ages of samples collected at the sampling locations. This dual approach confirms a middle Miocene to early Pleistocene age range for the collection. I described 155 species of reef forming corals collected across an Indo-Pacific longitudinal gradient. Twenty-two constitute new, extinct species from the genera Alveopora, Astreopora, Caulastrea, Cyphastrea, Echinopora, Euphyllia, Galaxea, Leptoria, Leptoseris, Madracis, Montipora, Platygyra, Symphyllia and Turbinaria. A further 42 taxa could not be assigned to species level due to poor preservation, but may well be additional new, extinct species. I uncovered a general pattern of coral turnover across the Indo-Pacific by investigating the degree to which coral communities (using both presence/absence and relative abundance of both coral species and genera) varied with water depth, time and geographical distribution. Coral communities were found to vary with global sea level and time. Thus global changes in sea level through time potentially drove extinction and origination in Indo-Pacific Neogene corals. Inverse Lyellian analysis indicates that of species present in the Miocene in New Britain, a mean of 41.8% are now extinct, possibly resulting from restricted flow of oceanic currents in that region. Indonesia (mean = 9.4%); and Fiji (mean = 6.6%) both had significantly lower proportions of extinct species. However, there is a decline in the number of extinct species found at any location from the middle Miocene (mean = 23.2%) to the early Pleistocene (mean = 1.8%). This study supports previously proposed models of an early Pliocene turnover event in Scleractinia in the Indo-Pacific.

The Bok globule B335 is a small molecular cloud in the solar neighbourhood near the galactic plane. The aim for this three-paper-study is to construct and analyze the extinction for this globule. The method we apply is to use the light from field stars behind the cloud in broadband filters ranging from UV to the mid-infrared. We have observations performed at the ESO telescopes at La Silla and Paranal as well as at the Nordic 2.5 m telescope at La Palma. Together with images and spectra from 2MASS-, ISO- and Spitzer-archives we are able to cover the wavelength range from 0.35 to 24 μm. An important tool to analyze these observations results in order to get the extinction is the grid of synthetic stellar atmospheric spectra provided by Hauschildt (2005). The extinction so received is a result in itself. From the analysis of the extinction wavelength dependence we derive properties of the dust, especially its composition and grain size distribution. By modeling the grain size distribution we are able to find the extinction from the reddening of the stars. We find that the extinction in the optical wavelength 0.35 to 2 μm range nicely follows the functional form described by Cardelli et al. (1989). Our result from the wavelength range redward of 2 μm show an extinction dependent on the part of the cloud examined. For the rim of the cloud we get an extinction similar to that reported earlier for the diffuse interstellar medium. From the central parts of the cloud, however, a higher extinction was found. Our grain size model contains a carbonaceous particle distribution and a silicate one. The result can be explained by depletion of carbon onto carbonaceous grains and also by carbon onto all grains including the silicates. Our modeling of the extinction and our classification of the background stars allow us to - determine the distance to the globule - estimate the gas column density ratio - estimate the mass of globule - get a handle on the dust conversion processes through the grain size distribution   From the water- and CO-ice spectra we are able to estimate the ice column densities. We find similar ice column densities for the two ices. The estimates differ, when calculated from band strengths or from Lorenz-Mie calculations of ice mantles on the grain size distribution, by a factor of two.

No description available.

Two-week sampling periods during the spring, summer, and fall of 2003, and the winter of 2004 were conducted utilizing a tandem differential mobility analyzer (TDMA) and, during the spring and summer, an aerodynamic particle sizer (APS), to characterize the seasonal variability of the Big Bend regions aerosol optical properties. Mass extinction efficiencies and relative humidity scattering enhancement factors were calculated for both externally and internally mixed aerosol populations for all size distributions collected, in an effort to possibly improve upon the default EPA mass extinction efficiencies used for all Class 1 areas across the United States. The mass extinction efficiencies calculated differed to some extent form the default values employed by the EPA. Sulfate, nitrate, and light absorbing carbon (LAC) exhibited a strong dependence on assumed mixing state, while, additionally, sulfate was also dependent on the assumed dominant aerosol. Seasonal variability was seen with all particle types, excluding LAC, with sulfate mass extinction efficiencies displaying the greatest variability with season. Calculated back trajectories indicated that air masses originating from the southeast had elevated mass extinction efficiencies, while, conversely, air masses originating from the southwest and northwest had the smallest mass extinction efficiencies.

Reproduction de : Thèse de doctorat : Droit privé : Reims : 2005. / Titre provenant de l'écran-titre. Bibliogr. p.390-411. Index.

Reproduction de : Thèse de doctorat : Droit : Lyon 3 : 2003. / Titre provenant de l'écran-titre.

Reproduction de : Thèse de doctorat : Droit : Poitiers : 2008. / Titre provenant de l'écran titre. Bibliogr. f. 406-432. Notes bibliogr. Index.

Thesis (M.A.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains viii, 38 p. : ill. Includes abstract. Includes bibliographical references (p. 33-37).

The purpose of the current study was to evaluate the conditions under which resurgence of appropriate communicative responses (mands) would occur with children with developmental disabilities. The experimental preparation consisted of a sequence of conditions that included (a) the reinforcement of one mand (i.e., microswitch activation or card exchange) on a FR 1 schedule, (b) an extinction condition in which the mand was no longer reinforced, (c) the reinforcement of a second mand (i.e., microswitch activation or card exchange) on a FR 1 schedule, and (d) a test for resurgence of the first mand which consisted of placing the second mand on extinction. The results demonstrated resurgence of mands during 2 out of 3 tests for resurgence for one participant. Resurgence of mands was demonstrated during all three tests for resurgence with the second participant. / text