title: Isolation of cellulolytic anaerobic extreme thermophiles from New Zealand thermal sites

authors: Sissons, Christopher H.

subjects: biology

abstract: Avicel enrichment cultures from 47 thermal-pool sites in the New Zealand Rotorua-Taupo region were screened for growth and carboxymethyl cellulase activity at 75°C. Eight anaerobic cellulolytic cultures were obtained. The effect of temperature on carboxymethyl cellulase activity was measured, and bacteria were isolated from the five best cultures. Bacteria from two sources designated TP8 and TP10 grew at 75°C, accumulated reducing sugar in the growth medium and gave free cellulases with avicelase activity. Bacteria from sources designated Tok4, Tok8, and Wai21 grew at 75°C, accumulated no free sugars in the medium, and gave free carboxymethyl cellulases with virtually no avicelase activity. All were obligate anaerobic nonsporeforming rods which stained gram negative, grew on pentoses as well as hexoses, and gave ethanol and acetate as major fermentation end products. The isolated strain which produced the most active and stable cellulases (trivially designated TP8.T) had lower rates of free endocellulase accumulation at 75°C than did Clostridium thermocellum at 60°C, but its cellulase activity against avicel and filter paper in culture supernatants was comparable. Tested at 85°C, TP8.T carboxymethyl cellulases included components which were very stable, whereas C. thermocellum carboxymethyl cellulases were all rapidly inactivated. The TP8.T avicelase activity was relatively unaffected by Triton X-100, EDTA, and dithiothreitol. Evidence was obtained for the existence of unisolated, cellulolytic extreme thermophiles producing cellulases which were more stable and active than those from TP8.T.

text: Isolation of cellulolytic anaerobic extreme thermophiles from New Zealand thermal sites Avicel enrichment cultures from 47 thermal-pool sites in the New Zealand Rotorua-Taupo region were screened for growth and carboxymethyl cellulase activity at 75°C. Eight anaerobic cellulolytic cultures were obtained. The effect of temperature on carboxymethyl cellulase activity was measured, and bacteria were isolated from the five best cultures. Bacteria from two sources designated TP8 and TP10 grew at 75°C, accumulated reducing sugar in the growth medium and gave free cellulases with avicelase activity. Bacteria from sources designated Tok4, Tok8, and Wai21 grew at 75°C, accumulated no free sugars in the medium, and gave free carboxymethyl cellulases with virtually no avicelase activity. All were obligate anaerobic nonsporeforming rods which stained gram negative, grew on pentoses as well as hexoses, and gave ethanol and acetate as major fermentation end products. The isolated strain which produced the most active and stable cellulases (trivially designated TP8.T) had lower rates of free endocellulase accumulation at 75°C than did Clostridium thermocellum at 60°C, but its cellulase activity against avicel and filter paper in culture supernatants was comparable. Tested at 85°C, TP8.T carboxymethyl cellulases included components which were very stable, whereas C. thermocellum carboxymethyl cellulases were all rapidly inactivated. The TP8.T avicelase activity was relatively unaffected by Triton X-100, EDTA, and dithiothreitol. Evidence was obtained for the existence of unisolated, cellulolytic extreme thermophiles producing cellulases which were more stable and active than those from TP8.T.

year: 1987

title: Enhanced spatial pyramid matching using log-polar-based image subdivision and representation

authors: Zhang, Edmond Yiwen

subjects: object categorization

abstract: This paper presents a new model for capturing spatial information for object categorization with bag-of-words (BOW). BOW models have recently become popular for the task of object recognition, owing to their good performance and simplicity. Much work has been proposed over the years to improve the BOW model, where the Spatial Pyramid Matching (SPM) technique is the most notable. We propose a new method to exploit spatial relationships between image features, based on binned log-polar grids. Our model works by partitioning the image into grids of different scales and orientations and computing histogram of local features within each grid. Experimental results show that our approach improves the results on three diverse datasets over the SPM technique.

text: Enhanced spatial pyramid matching using log-polar-based image subdivision and representation This paper presents a new model for capturing spatial information for object categorization with bag-of-words (BOW). BOW models have recently become popular for the task of object recognition, owing to their good performance and simplicity. Much work has been proposed over the years to improve the BOW model, where the Spatial Pyramid Matching (SPM) technique is the most notable. We propose a new method to exploit spatial relationships between image features, based on binned log-polar grids. Our model works by partitioning the image into grids of different scales and orientations and computing histogram of local features within each grid. Experimental results show that our approach improves the results on three diverse datasets over the SPM technique.

year: 2010

title: Academic success amongst a cohort of gifted and talented Māori and Pasifika secondary school boys: Elements that have contributed to their achievement

authors: Miller, Graeme Oliver

subjects: Māori

abstract: In recent years Māori and Pasifika students have been the focus of much discussion and a significant amount of research relating to underachievement. Despite this, many Māori and Pasifika secondary school boys are achieving highly in the academic sphere within the context of mainstream boys’ state secondary schools in New Zealand. Achievement aside, evidence shows that Māori and Pasifika secondary school boys are seriously under-represented in programmes for the gifted and talented. This enquiry examines factors in relation to identifying gifted and talented students, and investigates how their abilities are forged and nurtured. The reasons for student success merit serious investigation because of how the multiple elements contributing to their achievement are likely to be applicable to others, and are a pressing concern for academic attainment in the New Zealand education system. 
 
This qualitative study examines why 30 academically successful Māori and Pasifika secondary school boys achieved highly in the mainstream education system. The boys ranged from 13 to 19 years, the youngest being in his first year at high school as a Year 9 student, and the oldest being in his second year at university. The thesis argues their academic success was due to the complex interplay of home and school environmental elements, and the boys’ intrapersonal characteristics. The study explored the boys’ and parents’ narratives to explain why students had achieved highly, and examined both the parents’ and boys’ perceptions of how well the schools had provided for their intellectual, emotional and cultural needs. Sociocultural learning theory is the main theoretical lens through which the findings are viewed. The methodology is primarily built upon narrative inquiry. The main method of data collection was by semi-structured interview, both individually and in focus groups. Supplementary methods utilised were questionnaires and observation.  
  
An issue in the research was the disparity between the cultural and ethnic background of the participants and myself as the researcher. However, an endeavour was made to mitigate this by consulting with Māori and Pasifika educators, a kaumatua (elder) and iwi (tribal) representative prior to the research commencing. In addition, models developed through this study were submitted to Māori and Pasifika educators for their comment and approval prior to being included. 
 
With its focus specifically on highly-achieving Māori and Pasifika secondary school boys, this thesis makes an original contribution to the national and international discussion about raising student achievement. It provides a platform for further research to 	address the particular concerns around the underachievement of Māori and Pasifika secondary school boys. 
 
While there are several implications arising from the research, all are linked to the need for policy makers and educators to address the issue of the underrepresentation of Māori and Pasifika students in programmes for the gifted and talented. Policies, practices and relationships need to be examined to evaluate how effectively they contribute to gifted and talented Māori and Pasifika students receiving the academic opportunities they deserve. A key part of this examination will need to include consultation with students and their whānau.

text: Academic success amongst a cohort of gifted and talented Māori and Pasifika secondary school boys: Elements that have contributed to their achievement In recent years Māori and Pasifika students have been the focus of much discussion and a significant amount of research relating to underachievement. Despite this, many Māori and Pasifika secondary school boys are achieving highly in the academic sphere within the context of mainstream boys’ state secondary schools in New Zealand. Achievement aside, evidence shows that Māori and Pasifika secondary school boys are seriously under-represented in programmes for the gifted and talented. This enquiry examines factors in relation to identifying gifted and talented students, and investigates how their abilities are forged and nurtured. The reasons for student success merit serious investigation because of how the multiple elements contributing to their achievement are likely to be applicable to others, and are a pressing concern for academic attainment in the New Zealand education system. 
 
This qualitative study examines why 30 academically successful Māori and Pasifika secondary school boys achieved highly in the mainstream education system. The boys ranged from 13 to 19 years, the youngest being in his first year at high school as a Year 9 student, and the oldest being in his second year at university. The thesis argues their academic success was due to the complex interplay of home and school environmental elements, and the boys’ intrapersonal characteristics. The study explored the boys’ and parents’ narratives to explain why students had achieved highly, and examined both the parents’ and boys’ perceptions of how well the schools had provided for their intellectual, emotional and cultural needs. Sociocultural learning theory is the main theoretical lens through which the findings are viewed. The methodology is primarily built upon narrative inquiry. The main method of data collection was by semi-structured interview, both individually and in focus groups. Supplementary methods utilised were questionnaires and observation.  
  
An issue in the research was the disparity between the cultural and ethnic background of the participants and myself as the researcher. However, an endeavour was made to mitigate this by consulting with Māori and Pasifika educators, a kaumatua (elder) and iwi (tribal) representative prior to the research commencing. In addition, models developed through this study were submitted to Māori and Pasifika educators for their comment and approval prior to being included. 
 
With its focus specifically on highly-achieving Māori and Pasifika secondary school boys, this thesis makes an original contribution to the national and international discussion about raising student achievement. It provides a platform for further research to 	address the particular concerns around the underachievement of Māori and Pasifika secondary school boys. 
 
While there are several implications arising from the research, all are linked to the need for policy makers and educators to address the issue of the underrepresentation of Māori and Pasifika students in programmes for the gifted and talented. Policies, practices and relationships need to be examined to evaluate how effectively they contribute to gifted and talented Māori and Pasifika students receiving the academic opportunities they deserve. A key part of this examination will need to include consultation with students and their whānau.

year: 2015