title: Timing in Possums: Accounting for Resurgence in the Peak Procedure

authors: Stanley, Christopher D.

abstract: This study attempted to account for resurgence on the Peak Procedure using 6 possums (Trichosurus vulpecula) as subjects. The Peak Procedure is made up of randomly mixed fixed intervals (FI) and peak intervals (PI), with the ratio of FI trials to PI trials being 4:1 respectively. Conditions 1-4 were used to replicate Church et al.’s (1991) procedure from their second experiment. The authors found that when the PI trial length was variable, data from PI trials showed that responding did not resurge, as it did when the PI duration was fixed.  Condition 1 used a FI 20 s and a variable PI with a mean of 80 s. Responding did not resurge, but rather decreased to a low level throughout the PI trial. Condition 2 used a FI 20 and a fixed PI of 100 s. Responding resurged for this condition. Condition 3 and 4 repeated Condition 1 and 2 respectively to give an ABAB design. Responding again decreased and increased as the PI changed to being variable and fixed respectively. These results are similar to that found by Church et al. (1991), and show support for what Sanabria and Killeen (2007) call the anticipation theory (where escape from a non-reinforced PI trial is negatively reinforcing). The PI duration was shortened to twice the FI length in Condition 5 and lengthened to 300 s, or 15 times the FI in Condition 6. This was in order to investigate whether responding would resurge at very short and very long PI durations. Responding did not resurge at the shorter PI length, and this may be due to there not being enough time to do so. At the extreme length of 300 s, responding was seen to resurge; a result that is not consistent with other studies that used a similar procedure (Sanabria & Killeen, 2007). When the procedure returned to using a FI 20 s and a variable PI with a mean of 80 s in Condition 7, resurgence decreased to a minimum and remained stable till the end of the trial. 
Results from the present study support Church et al.’s (1991) anticipation theory, and that as long as the animals can track the end of the PI trial, responding will resurge; if it is variable, animals cannot predict the end of the trial and so response resurgence does not occur.

text: Timing in Possums: Accounting for Resurgence in the Peak Procedure This study attempted to account for resurgence on the Peak Procedure using 6 possums (Trichosurus vulpecula) as subjects. The Peak Procedure is made up of randomly mixed fixed intervals (FI) and peak intervals (PI), with the ratio of FI trials to PI trials being 4:1 respectively. Conditions 1-4 were used to replicate Church et al.’s (1991) procedure from their second experiment. The authors found that when the PI trial length was variable, data from PI trials showed that responding did not resurge, as it did when the PI duration was fixed.  Condition 1 used a FI 20 s and a variable PI with a mean of 80 s. Responding did not resurge, but rather decreased to a low level throughout the PI trial. Condition 2 used a FI 20 and a fixed PI of 100 s. Responding resurged for this condition. Condition 3 and 4 repeated Condition 1 and 2 respectively to give an ABAB design. Responding again decreased and increased as the PI changed to being variable and fixed respectively. These results are similar to that found by Church et al. (1991), and show support for what Sanabria and Killeen (2007) call the anticipation theory (where escape from a non-reinforced PI trial is negatively reinforcing). The PI duration was shortened to twice the FI length in Condition 5 and lengthened to 300 s, or 15 times the FI in Condition 6. This was in order to investigate whether responding would resurge at very short and very long PI durations. Responding did not resurge at the shorter PI length, and this may be due to there not being enough time to do so. At the extreme length of 300 s, responding was seen to resurge; a result that is not consistent with other studies that used a similar procedure (Sanabria & Killeen, 2007). When the procedure returned to using a FI 20 s and a variable PI with a mean of 80 s in Condition 7, resurgence decreased to a minimum and remained stable till the end of the trial. 
Results from the present study support Church et al.’s (1991) anticipation theory, and that as long as the animals can track the end of the PI trial, responding will resurge; if it is variable, animals cannot predict the end of the trial and so response resurgence does not occur.

year: 2013

title: Challenges and opportunities for integrating lake ecosystem modelling approaches

authors: Mooij, Wolf M.

subjects: aquatic

abstract: A large number and wide variety of lake ecosystem models have been developed and published during the past four decades. We identify two challenges for making further progress in this field. One such challenge is to avoid developing more models largely following the concept of others (‘reinventing the wheel’). The other challenge is to avoid focusing on only one type of model, while ignoring new and diverse approaches that have become available (‘having tunnel vision’). In this paper, we aim at improving the awareness of existing models and knowledge of concurrent approaches in lake ecosystem modelling, without covering all possible model tools and avenues. First, we present a broad variety of modelling approaches. To illustrate these approaches, we give brief descriptions of rather arbitrarily selected sets of specific models. We deal with static models (steady state and regression models), complex dynamic models (CAEDYM, CE-QUAL-W2, Delft 3D-ECO, LakeMab, LakeWeb, MyLake, PCLake, PROTECH, SALMO), structurally dynamic models and minimal dynamic models. We also discuss a group of approaches that could all be classified as individual based: super-individual models (Piscator, Charisma), physiologically structured models, stage-structured models and trait-based models. We briefly mention genetic algorithms, neural networks, Kalman filters and fuzzy logic. Thereafter, we zoom in, as an in-depth example, on the multi-decadal development and application of the lake ecosystem model PCLake and related models (PCLake Metamodel, Lake Shira Model, IPH-TRIM3D-PCLake). In the discussion, we argue that while the historical development of each approach and model is understandable given its ‘leading principle’, there are many opportunities for combining approaches. We take the point of view that a single ‘right’ approach does not exist and should not be strived for. Instead, multiple modelling approaches, applied concurrently to a given problem, can help develop an integrative view on the functioning of lake ecosystems. We end with a set of specific recommendations that may be of help in the further development of lake ecosystem models.

text: Challenges and opportunities for integrating lake ecosystem modelling approaches A large number and wide variety of lake ecosystem models have been developed and published during the past four decades. We identify two challenges for making further progress in this field. One such challenge is to avoid developing more models largely following the concept of others (‘reinventing the wheel’). The other challenge is to avoid focusing on only one type of model, while ignoring new and diverse approaches that have become available (‘having tunnel vision’). In this paper, we aim at improving the awareness of existing models and knowledge of concurrent approaches in lake ecosystem modelling, without covering all possible model tools and avenues. First, we present a broad variety of modelling approaches. To illustrate these approaches, we give brief descriptions of rather arbitrarily selected sets of specific models. We deal with static models (steady state and regression models), complex dynamic models (CAEDYM, CE-QUAL-W2, Delft 3D-ECO, LakeMab, LakeWeb, MyLake, PCLake, PROTECH, SALMO), structurally dynamic models and minimal dynamic models. We also discuss a group of approaches that could all be classified as individual based: super-individual models (Piscator, Charisma), physiologically structured models, stage-structured models and trait-based models. We briefly mention genetic algorithms, neural networks, Kalman filters and fuzzy logic. Thereafter, we zoom in, as an in-depth example, on the multi-decadal development and application of the lake ecosystem model PCLake and related models (PCLake Metamodel, Lake Shira Model, IPH-TRIM3D-PCLake). In the discussion, we argue that while the historical development of each approach and model is understandable given its ‘leading principle’, there are many opportunities for combining approaches. We take the point of view that a single ‘right’ approach does not exist and should not be strived for. Instead, multiple modelling approaches, applied concurrently to a given problem, can help develop an integrative view on the functioning of lake ecosystems. We end with a set of specific recommendations that may be of help in the further development of lake ecosystem models.

year: 2010

title: Indigenizing outdoor play in New Zealand: A conversation analysis approach

authors: Bateman, Amanda

abstract: This chapter focuses on a single case analysis of one trip to a local bush reserve in New Zealand. The observations included in this chapter begin by exploring the way in which a promise to the Maori God Tane Mahuta is managed by the teachers and children at the beginning of the excursion. The promise made is part of the mundane, everyday activity engaged in by these children and teachers during their weekly visit to the bush reserve, where every child is required to recite a phrase that promises not to hurt the creatures, animals or plants of Tane Mahuta when they are playing in the forest. In the first of the video-recorded episodes, explicit reference to Tane Mahuta is initially oriented through one of the children reciting the promise, unprompted, at the beginning of the recording. The second observation reveals one of the teachers explaining to a child the rules of entering the forest: that you have to ask permission from Tane Mahuta before you enter. When a child does not want to say the promise, he is encouraged to do so collaboratively with the teacher before entering the forest. Only once the child has said the promise does he enter, demonstrating the importance of the verbal commitment and participation in the accountable action of promise-making by the participants prior to entering the forest.

text: Indigenizing outdoor play in New Zealand: A conversation analysis approach This chapter focuses on a single case analysis of one trip to a local bush reserve in New Zealand. The observations included in this chapter begin by exploring the way in which a promise to the Maori God Tane Mahuta is managed by the teachers and children at the beginning of the excursion. The promise made is part of the mundane, everyday activity engaged in by these children and teachers during their weekly visit to the bush reserve, where every child is required to recite a phrase that promises not to hurt the creatures, animals or plants of Tane Mahuta when they are playing in the forest. In the first of the video-recorded episodes, explicit reference to Tane Mahuta is initially oriented through one of the children reciting the promise, unprompted, at the beginning of the recording. The second observation reveals one of the teachers explaining to a child the rules of entering the forest: that you have to ask permission from Tane Mahuta before you enter. When a child does not want to say the promise, he is encouraged to do so collaboratively with the teacher before entering the forest. Only once the child has said the promise does he enter, demonstrating the importance of the verbal commitment and participation in the accountable action of promise-making by the participants prior to entering the forest.

year: 2017