title: Astroenzymology – the environmental limits of enzyme activity

authors: Daniel, Roy M.

subjects: hydration

abstract: Using organisms from extreme terrestrial environments as models for extraterrestrial life may lead us to underestimate the range of environments that life may inhabit. An alternative approach is to inspect the range of conditions over which crucial biomolecules might function. Recent investigations of enzyme activity suggest that they have the potential to function over a wider range of environmental conditions than expected. Although the upper temperature limit for enzyme stability is unclear, some enzymes are active up to 130°C. The evidence is that the instability of enzymes is a functional requirement, rather then because of any restraint on achieving higher stability. There is no evidence that enzyme activity ceases at low temperatures; it declines in a predictable manner to the lowest temperature at which it has been possible to make measurements, -100°C. It has been generally accepted that dehydration stops enzyme activity but this acceptance may have arisen partly from the technical difficulty of assessing enzyme activity without a fluid medium for diffusion. Experiments using anhydrous organic solvents or gas phase substrates suggest activity occurs in enzymes at very low hydration.

text: Astroenzymology – the environmental limits of enzyme activity Using organisms from extreme terrestrial environments as models for extraterrestrial life may lead us to underestimate the range of environments that life may inhabit. An alternative approach is to inspect the range of conditions over which crucial biomolecules might function. Recent investigations of enzyme activity suggest that they have the potential to function over a wider range of environmental conditions than expected. Although the upper temperature limit for enzyme stability is unclear, some enzymes are active up to 130°C. The evidence is that the instability of enzymes is a functional requirement, rather then because of any restraint on achieving higher stability. There is no evidence that enzyme activity ceases at low temperatures; it declines in a predictable manner to the lowest temperature at which it has been possible to make measurements, -100°C. It has been generally accepted that dehydration stops enzyme activity but this acceptance may have arisen partly from the technical difficulty of assessing enzyme activity without a fluid medium for diffusion. Experiments using anhydrous organic solvents or gas phase substrates suggest activity occurs in enzymes at very low hydration.

year: 2003-02

title: Ground Plane Segmentation of Time-of-Flight Images for Asparagus Harvesting

authors: Peebles, Matthew Christopher Scott

subjects: Science & Technology

abstract: A key task in processing time-of-flight images for the detection of asparagus spears is the identification and segmentation of the ground plane. In this paper, we aim to compare the performance of RANSAC with a modified version of an existing deterministic method, namely Hyun’s method. Each method is tested on scenes with varying amounts of field clutter. Additionally, a variety of camera angles are investigated. We find that both RANSAC and the proposed method produce ground plane predictions with a root mean square error of less than 0.05m and execute at a rate of approximately 0.056s per frame. However, RANSAC was shown to be much less reliable in high clutter scenes. The camera mounting angle is found to significantly affect the density and noise of points in time-of-flight images. These factors translate to significantly worse performance for both methods at low camera angles.

text: Ground Plane Segmentation of Time-of-Flight Images for Asparagus Harvesting A key task in processing time-of-flight images for the detection of asparagus spears is the identification and segmentation of the ground plane. In this paper, we aim to compare the performance of RANSAC with a modified version of an existing deterministic method, namely Hyun’s method. Each method is tested on scenes with varying amounts of field clutter. Additionally, a variety of camera angles are investigated. We find that both RANSAC and the proposed method produce ground plane predictions with a root mean square error of less than 0.05m and execute at a rate of approximately 0.056s per frame. However, RANSAC was shown to be much less reliable in high clutter scenes. The camera mounting angle is found to significantly affect the density and noise of points in time-of-flight images. These factors translate to significantly worse performance for both methods at low camera angles.

year: 2018

title: Learning in later life: a bicultural perspective from Aotearoa/New Zealand

authors: Findsen, Brian

abstract: This article is concerned with how learning in later life has been constructed and practised by the two most numerous ethnic groups in Aotearoa/New Zealand, Pākėhā (Europeans) and Māori (Indigenous people). It is argued that learning is heavily influenced by historic features of interaction between these two groups; Pākehā as the dominant cultural and economic group and Māori as subordinate. While contemporary perspectives are necessarily interpreted in the light of historical trends and events, fresh interpretations of what constitutes biculturalism in this country allow for more nuanced understanding of possibilities for and obstacles to older adult learning/education. Themes from lifelong learning are analysed with special reference to older people’s learning, the consequences of Māori sovereignty on pedagogy and trends identified for older adult education. Two linked case studies of Pākehā and Māori older adult education in a New Zealand university are described to illustrate complexities and tensions in provision in a bicultural context.

text: Learning in later life: a bicultural perspective from Aotearoa/New Zealand This article is concerned with how learning in later life has been constructed and practised by the two most numerous ethnic groups in Aotearoa/New Zealand, Pākėhā (Europeans) and Māori (Indigenous people). It is argued that learning is heavily influenced by historic features of interaction between these two groups; Pākehā as the dominant cultural and economic group and Māori as subordinate. While contemporary perspectives are necessarily interpreted in the light of historical trends and events, fresh interpretations of what constitutes biculturalism in this country allow for more nuanced understanding of possibilities for and obstacles to older adult learning/education. Themes from lifelong learning are analysed with special reference to older people’s learning, the consequences of Māori sovereignty on pedagogy and trends identified for older adult education. Two linked case studies of Pākehā and Māori older adult education in a New Zealand university are described to illustrate complexities and tensions in provision in a bicultural context.

year: 2016