title: Benthic microbial communities of coastal terrestrial and ice shelf Antarctic meltwater ponds.

authors: Archer, Stephen David James

subjects: Antarctic

abstract: The numerous perennial meltwater ponds distributed throughout Antarctica represent diverse and productive ecosystems central to the ecological functioning of the surrounding ultra oligotrophic environment. The dominant taxa in the pond benthic communities have been well described however, little is known regarding their regional dispersal and local drivers to community structure. The benthic microbial communities of 12 meltwater ponds in the McMurdo Sound of Antarctica were investigated to examine variation between pond microbial communities and their biogeography. Geochemically comparable but geomorphologically distinct ponds were selected from Bratina Island (ice shelf) and Miers Valley (terrestrial) (<40 km between study sites), and community structure within ponds was compared using DNA fingerprinting and pyrosequencing of 16S rRNA gene amplicons. More than 85% of total sequence reads were shared between pooled benthic communities at different locations (OTU0.05), which in combination with favorable prevailing winds suggests aeolian regional distribution. Consistent with previous findings Proteobacteria and Bacteroidetes were the dominant phyla representing over 50% of total sequences; however, a large number of other phyla (21) were also detected in this ecosystem. Although dominant Bacteria were ubiquitous between ponds, site and local selection resulted in heterogeneous community structures and with more than 45% of diversity being pond specific. Potassium was identified as the most significant contributing factor to the cosmopolitan community structure and aluminum to the location unique community based on a BEST analysis (Spearman's correlation coefficient of 0.632 and 0.806, respectively). These results indicate that the microbial communities in meltwater ponds are easily dispersed regionally and that the local geochemical environment drives the ponds community structure.

text: Benthic microbial communities of coastal terrestrial and ice shelf Antarctic meltwater ponds. The numerous perennial meltwater ponds distributed throughout Antarctica represent diverse and productive ecosystems central to the ecological functioning of the surrounding ultra oligotrophic environment. The dominant taxa in the pond benthic communities have been well described however, little is known regarding their regional dispersal and local drivers to community structure. The benthic microbial communities of 12 meltwater ponds in the McMurdo Sound of Antarctica were investigated to examine variation between pond microbial communities and their biogeography. Geochemically comparable but geomorphologically distinct ponds were selected from Bratina Island (ice shelf) and Miers Valley (terrestrial) (<40 km between study sites), and community structure within ponds was compared using DNA fingerprinting and pyrosequencing of 16S rRNA gene amplicons. More than 85% of total sequence reads were shared between pooled benthic communities at different locations (OTU0.05), which in combination with favorable prevailing winds suggests aeolian regional distribution. Consistent with previous findings Proteobacteria and Bacteroidetes were the dominant phyla representing over 50% of total sequences; however, a large number of other phyla (21) were also detected in this ecosystem. Although dominant Bacteria were ubiquitous between ponds, site and local selection resulted in heterogeneous community structures and with more than 45% of diversity being pond specific. Potassium was identified as the most significant contributing factor to the cosmopolitan community structure and aluminum to the location unique community based on a BEST analysis (Spearman's correlation coefficient of 0.632 and 0.806, respectively). These results indicate that the microbial communities in meltwater ponds are easily dispersed regionally and that the local geochemical environment drives the ponds community structure.

year: 2015

title: The relative effectiveness of different forms of microteaching incorporating a sensitisation approach

authors: Katterns, Robert

abstract: This study examined the relative effectiveness of several different forms of microteaching as compared with equivalent courses in observation-analysis of teaching and regular pre-service study in the principles of teaching. The microteaching courses incorporated a sensitisation, rather than a skills-training, approach and emphasised the usefulness of various questioning strategies and the development of sensitive and flexible control of a repertoire of questioning skills. The subjects were 96 student teachers in the primary school division of a New Zealand Teachers College.
Three sets of treatments were studied as interrelated parts of an overall research design. First, an examination was made of the relative effects on teaching performance of microteaching, observation-analysis and regular coursework. Secondly, comparisons were made of the effects of different media (video and audiotape) in the microteaching and observation-analysis programmes. Thirdly, a study was made of the relative effects of microteaching treatments involving different “pupils” (children or student teacher peers), different media (video or audiotape), different question types to be practised (middle or high order), and various combinations of these treatments.
Data on subjects’ cognitive questioning skills and talk patterns were obtained by analysing transcripts of discussion lessons taken before and after treatment. The overall and differential effects of treatments in each research design on these behavioural variables were tested by the use of correlated t tests, and analysis of variance and covariance procedures, respectively. In addition, the reaction of microteaching and observation-analysis participants to their learning experiences was investigated by means of opinion questionnaires.
Observation-analysis and regular coursework both produced some significant changes in teaching performance. Microteaching, however, was significantly more effective than either of these two treatments in helping student teachers to increase fluency-control in questioning, to develop fewer but more searching discussion episodes through the use of high order initial and probing questions, to decrease the amount of teacher talk, and to minimise questioning that leads to simple yes/no answers. Microteaching also appeared superior to regular coursework in reducing the tendency to repeat pupil responses, and in increasing unsolicited pupil answering and pupil-to-pupil dialogue. A similar pattern of results favouring microteaching was evident in comparisons made between the two media treatments in microteaching and observation-analysis, and between these treatments and regular coursework.
The most striking findings in the study, however, were the equivalent effects overall of the different pupil, media and question type treatments in microteaching, and of the various combinations of these treatments. In the development of questioning skills in the small group discussion situation, these results suggest that a Teachers College might reduce the logistic, resource and time problems in the provision of microteaching by having students: (i) teach their peers instead of children; (ii) use audiotape instead of videotape to support analysis of teaching and feedback activities; and (iii) practise some types of questions only while learning to use other questioning skills ‘vicariously’ through observing them being used by fellow microteachers.

text: The relative effectiveness of different forms of microteaching incorporating a sensitisation approach This study examined the relative effectiveness of several different forms of microteaching as compared with equivalent courses in observation-analysis of teaching and regular pre-service study in the principles of teaching. The microteaching courses incorporated a sensitisation, rather than a skills-training, approach and emphasised the usefulness of various questioning strategies and the development of sensitive and flexible control of a repertoire of questioning skills. The subjects were 96 student teachers in the primary school division of a New Zealand Teachers College.
Three sets of treatments were studied as interrelated parts of an overall research design. First, an examination was made of the relative effects on teaching performance of microteaching, observation-analysis and regular coursework. Secondly, comparisons were made of the effects of different media (video and audiotape) in the microteaching and observation-analysis programmes. Thirdly, a study was made of the relative effects of microteaching treatments involving different “pupils” (children or student teacher peers), different media (video or audiotape), different question types to be practised (middle or high order), and various combinations of these treatments.
Data on subjects’ cognitive questioning skills and talk patterns were obtained by analysing transcripts of discussion lessons taken before and after treatment. The overall and differential effects of treatments in each research design on these behavioural variables were tested by the use of correlated t tests, and analysis of variance and covariance procedures, respectively. In addition, the reaction of microteaching and observation-analysis participants to their learning experiences was investigated by means of opinion questionnaires.
Observation-analysis and regular coursework both produced some significant changes in teaching performance. Microteaching, however, was significantly more effective than either of these two treatments in helping student teachers to increase fluency-control in questioning, to develop fewer but more searching discussion episodes through the use of high order initial and probing questions, to decrease the amount of teacher talk, and to minimise questioning that leads to simple yes/no answers. Microteaching also appeared superior to regular coursework in reducing the tendency to repeat pupil responses, and in increasing unsolicited pupil answering and pupil-to-pupil dialogue. A similar pattern of results favouring microteaching was evident in comparisons made between the two media treatments in microteaching and observation-analysis, and between these treatments and regular coursework.
The most striking findings in the study, however, were the equivalent effects overall of the different pupil, media and question type treatments in microteaching, and of the various combinations of these treatments. In the development of questioning skills in the small group discussion situation, these results suggest that a Teachers College might reduce the logistic, resource and time problems in the provision of microteaching by having students: (i) teach their peers instead of children; (ii) use audiotape instead of videotape to support analysis of teaching and feedback activities; and (iii) practise some types of questions only while learning to use other questioning skills ‘vicariously’ through observing them being used by fellow microteachers.

year: 1977

title: Development and care of pā harakeke in 19th century New Zealand: Voices from the past

authors: McAllum, Priscilla M

subjects: Raranga

abstract: Māori weaving is experiencing a resurgence. Some weavers are involved in the planting of pā harakeke so that they have a high quality resource on hand ready for use.  A number of recent scientific publications, undertaken jointly with weavers, have explored the unique fibre qualities of different harakeke varieties along with specific aspects of Māori use of these varieties. In this paper, I examine Māori planting practices of pā harakeke and other aspects of resource management as revealed in literature sources from the late 18th to the early 20th centuries.  Although some of the practices outlined here may have fallen into disuse over time, they may, nevertheless, continue to be appropriate for contemporary pā harakeke. It is hoped, therefore, that the information provided here will be of interest to contemporary weavers.

text: Development and care of pā harakeke in 19th century New Zealand: Voices from the past Māori weaving is experiencing a resurgence. Some weavers are involved in the planting of pā harakeke so that they have a high quality resource on hand ready for use.  A number of recent scientific publications, undertaken jointly with weavers, have explored the unique fibre qualities of different harakeke varieties along with specific aspects of Māori use of these varieties. In this paper, I examine Māori planting practices of pā harakeke and other aspects of resource management as revealed in literature sources from the late 18th to the early 20th centuries.  Although some of the practices outlined here may have fallen into disuse over time, they may, nevertheless, continue to be appropriate for contemporary pā harakeke. It is hoped, therefore, that the information provided here will be of interest to contemporary weavers.

year: 2005-02