title: Case studies

authors: Weyers, Benjamin

subjects: Computer science

abstract: This chapter introduces a set of case studies that are used in the rest of the book. They encompass well known problem domains in Human-Computer Interaction research and provide a practical focus for the approaches presented in this book. The set of case studies includes case studies concerned with: the controller interface to a (semi-automated) nuclear power plant; a partly-autonomous arrival management interactive system in the domain of air-traffic control; a user interface for new interactive cockpits and an interactive system used in rural and urban areas to maintain wind turbines. The final case study brings an interesting perspective for formal techniques, namely interactive public displays.

text: Case studies This chapter introduces a set of case studies that are used in the rest of the book. They encompass well known problem domains in Human-Computer Interaction research and provide a practical focus for the approaches presented in this book. The set of case studies includes case studies concerned with: the controller interface to a (semi-automated) nuclear power plant; a partly-autonomous arrival management interactive system in the domain of air-traffic control; a user interface for new interactive cockpits and an interactive system used in rural and urban areas to maintain wind turbines. The final case study brings an interesting perspective for formal techniques, namely interactive public displays.

year: 2017

title: The eco-physiology of New Zealand forest lichens with special reference to carbon dioxide exchange

authors: Snelgar, W.P.

abstract: This study of lichen ecological physiology was carried out in four parts:

(i) The growth rates of specimens of Pseudocyphellaria homoeophylla and Sticta caperata growing in the Urewera National Park (New Zealand) were measured photographically. The mean radial increase of P. homoeophylla was related to thallus diameter and rates as high 27 mm yr⁻¹ (32 cm diameter) were recorded. The growth of S. caperata was not influenced by thallus size and the mean radial increase was 7.0 mm yr⁻¹.

(ii) The intraspecific morphological variations of Pseudocyphellaria dissimilis populations are assessed and are related to the nitrogenase activity and water relations of each population. The effect of thallus water content on CO₂ exchange in eight lichen and one bryophyte species was studied using an infrared gas analyser operating as a discrete sample analyser. Species from moist habitats showed a net loss of CO₂ at low thallus water contents whilst some other species showed a depression of net photosynthesis (NP) at high thallus water contents. In Sticta latifrons this depression was less apparent when the lower surface was dried. Experiments with a split chamber demonstrated that virtually all CO₂ uptake occurs through the lower, cyphellate surface. These results suggest that the cyphellae of S. latifrons act as air pores and that blockage of these pores with water results in a depression of NP.

(iii) Low oxygen concentrations (1% v/v) were shown to increase NP in S. latifrons, P. homoeophylla and P. billardierii by up to 55%. This stimulation was considered to result from the repression of photorespiration. The oxygen effect was separated into two components; (a) the sensitivity of the carboxylation system and (b), the rate of CO₂ evolution in the light at zero CO₂. Of the lichen species studied all but P. billardierii had a carboxylation sensitivity typical of the values expected in C3 plants. P. billardierii had an unusually low carboxylation sensitivity. The rate of CO₂ evolution in the light showed large inter and intraspecific variations. Low rates of CO₂ evolution were often associated with a high CO₂ refixation ability.

(iv) Total CO₂ diffusion resistance - water content curves for six lichen species are presented. All species show increased resistances at low thallus water contents and some also show high resistances at high thallus water contents. The total CO₂ resistances of S. latifrons and P. amphisticta are separated into transport and carboxylation components. Cyphella, pseudocyphella, and medulla resistances are calculated from morphological data. Although transport resistances are often larger than carboxylation resistances the results suggest that at ambient CO₂ levels carboxylation processes limit photosynthesis. The relationship between resistance to water vapour loss and resistance to CO₂ uptake in P. homoeophylla and S. latifrons is established and the ecological implications are discussed.

In a general summary, the size of the internal and external water holding capacities of several lichen species is estimated. The effectiveness of these reserves in maintaining lichens in a moist condition in the field is calculated and the results are related to the ecology of the species. Morphological adaptations of Stictaceae lichens which maximise water holding capacity yet minimise CO₂ diffusion resistances are considered. It is suggested that lichen water contents should be related to thallus area, rather than thallus weight, as the former parameter appears to be of greater physiological significance. 

The relevance of this work to that of previous authors is discussed, particularly in regard to photorespiration, CO₂ uptake, and thallus water content in lichens.

text: The eco-physiology of New Zealand forest lichens with special reference to carbon dioxide exchange This study of lichen ecological physiology was carried out in four parts:

(i) The growth rates of specimens of Pseudocyphellaria homoeophylla and Sticta caperata growing in the Urewera National Park (New Zealand) were measured photographically. The mean radial increase of P. homoeophylla was related to thallus diameter and rates as high 27 mm yr⁻¹ (32 cm diameter) were recorded. The growth of S. caperata was not influenced by thallus size and the mean radial increase was 7.0 mm yr⁻¹.

(ii) The intraspecific morphological variations of Pseudocyphellaria dissimilis populations are assessed and are related to the nitrogenase activity and water relations of each population. The effect of thallus water content on CO₂ exchange in eight lichen and one bryophyte species was studied using an infrared gas analyser operating as a discrete sample analyser. Species from moist habitats showed a net loss of CO₂ at low thallus water contents whilst some other species showed a depression of net photosynthesis (NP) at high thallus water contents. In Sticta latifrons this depression was less apparent when the lower surface was dried. Experiments with a split chamber demonstrated that virtually all CO₂ uptake occurs through the lower, cyphellate surface. These results suggest that the cyphellae of S. latifrons act as air pores and that blockage of these pores with water results in a depression of NP.

(iii) Low oxygen concentrations (1% v/v) were shown to increase NP in S. latifrons, P. homoeophylla and P. billardierii by up to 55%. This stimulation was considered to result from the repression of photorespiration. The oxygen effect was separated into two components; (a) the sensitivity of the carboxylation system and (b), the rate of CO₂ evolution in the light at zero CO₂. Of the lichen species studied all but P. billardierii had a carboxylation sensitivity typical of the values expected in C3 plants. P. billardierii had an unusually low carboxylation sensitivity. The rate of CO₂ evolution in the light showed large inter and intraspecific variations. Low rates of CO₂ evolution were often associated with a high CO₂ refixation ability.

(iv) Total CO₂ diffusion resistance - water content curves for six lichen species are presented. All species show increased resistances at low thallus water contents and some also show high resistances at high thallus water contents. The total CO₂ resistances of S. latifrons and P. amphisticta are separated into transport and carboxylation components. Cyphella, pseudocyphella, and medulla resistances are calculated from morphological data. Although transport resistances are often larger than carboxylation resistances the results suggest that at ambient CO₂ levels carboxylation processes limit photosynthesis. The relationship between resistance to water vapour loss and resistance to CO₂ uptake in P. homoeophylla and S. latifrons is established and the ecological implications are discussed.

In a general summary, the size of the internal and external water holding capacities of several lichen species is estimated. The effectiveness of these reserves in maintaining lichens in a moist condition in the field is calculated and the results are related to the ecology of the species. Morphological adaptations of Stictaceae lichens which maximise water holding capacity yet minimise CO₂ diffusion resistances are considered. It is suggested that lichen water contents should be related to thallus area, rather than thallus weight, as the former parameter appears to be of greater physiological significance. 

The relevance of this work to that of previous authors is discussed, particularly in regard to photorespiration, CO₂ uptake, and thallus water content in lichens.

year: 1981

title: Transformative pedagogy and language learning in Maori and Irish contexts

authors: Glynn, Ted

subjects: transformative pedagogy

abstract: Establishing positive learning communities in classrooms where pedagogies are socially and culturally responsive and centred on shared life experiences is critical for the revitalisation of minoritised languages such as Irish and Māori, which lack the dominance and power of the wider languages of government and communication. Transformative pedagogy and pedagogical re-positioning of teachers are essential to legitimising and affirming minoritised languages in the classroom. Three small-scale New Zealand studies of emerging literacy in Māori are introduced, exemplifying a responsive and transformative pedagogy that enables teachers to position themselves as socially and culturally responsive participants within classroom contexts. These studies offer strategies that might facilitate the development of similar transformative pedagogy in Irish contexts also.

text: Transformative pedagogy and language learning in Maori and Irish contexts Establishing positive learning communities in classrooms where pedagogies are socially and culturally responsive and centred on shared life experiences is critical for the revitalisation of minoritised languages such as Irish and Māori, which lack the dominance and power of the wider languages of government and communication. Transformative pedagogy and pedagogical re-positioning of teachers are essential to legitimising and affirming minoritised languages in the classroom. Three small-scale New Zealand studies of emerging literacy in Māori are introduced, exemplifying a responsive and transformative pedagogy that enables teachers to position themselves as socially and culturally responsive participants within classroom contexts. These studies offer strategies that might facilitate the development of similar transformative pedagogy in Irish contexts also.

year: 2009