title: Evolution and comparative haemoglobin oxygen binding in new zealand mudfishes

authors: Brijs, Jeroen

subjects: mudfish

abstract: New Zealand's five endemic mudfish (Neochanna spp.) species have distributions that differ both geographically and by habitat type. Differences in habitat preferences between species have led to the proposal of an evolutionary series within the group. A morphological cline can be observed from the galaxiform Chatham Island and Canterbury species inhabiting lakes and streams, respectively, to the anguilliform Northland and brown mudfishes of ephemeral wetlands. Morphological specializations proposed for wetland dwelling include loss of pelvic fins, reduced eyes, enlarged nostrils, development of caudal flanges, and elongation of dorsal and anal fin bases to become almost confluent with the caudal fin.  Another expectation of adaptation to wetland dwelling is specializations in respiratory physiology to obtain oxygen from highly hypoxic or acidic waters, and the ability to cope with seasonal exposure to air during the drought season.  Expected respiratory specializations to wetland dwelling include high oxygen affinity haemoglobins, high levels of cooperative oxygen binding, the presence of multiple haemoglobins and the ability to aestivate and survive long periods of emersion. 

The four mainland Neochanna species were examined to determine if differences in haemoglobin expression as well as differences in haemoglobin oxygen binding correlated with differing habitats and treatments.  Whole blood oxygen affinity was determined at several pH levels (6.5, 7.0, 7.5 and 8.0) and temperatures (10'C, 15'C and 20'C), as well as different treatments (aestivating, fasting and control) using a Hemox analyzer.  The presence of multiple haemoglobins was determined by isoelectric focusing.  All four species displayed high oxygen affinities (p50 = 6.5 to 9.5 mm Hg at pH 7.5  15'C), moderate levels of cooperativity (Hill coefficients = 1.75 to 2.00 at pH 7.5  15'C), pH sensitivity (Bohr coefficients = -0.62 to -0.94 between pH 7.5 and 7.0 at 15'C), temperature sensitivity (ΔH = -2.20 to -15.78 k cal mol-1 between 10'C and 15'C) and the presence of multiple haemoglobins.  Black, brown and Northland mudfish were able to survive aestivation for six weeks but there were no changes between air-breathing and water-breathing individuals with respect to oxygen binding characteristics.  Although there is evidence of habitat specialization in haemoglobin physiology between mudfish species, differences between species did not correlate with the evolutionary series proposed for specialization to dwelling in ephemeral wetlands and latitudinal distributions of mudfish species appear to strongly dictate oxygen binding properties of mudfish whole blood.

text: Evolution and comparative haemoglobin oxygen binding in new zealand mudfishes New Zealand's five endemic mudfish (Neochanna spp.) species have distributions that differ both geographically and by habitat type. Differences in habitat preferences between species have led to the proposal of an evolutionary series within the group. A morphological cline can be observed from the galaxiform Chatham Island and Canterbury species inhabiting lakes and streams, respectively, to the anguilliform Northland and brown mudfishes of ephemeral wetlands. Morphological specializations proposed for wetland dwelling include loss of pelvic fins, reduced eyes, enlarged nostrils, development of caudal flanges, and elongation of dorsal and anal fin bases to become almost confluent with the caudal fin.  Another expectation of adaptation to wetland dwelling is specializations in respiratory physiology to obtain oxygen from highly hypoxic or acidic waters, and the ability to cope with seasonal exposure to air during the drought season.  Expected respiratory specializations to wetland dwelling include high oxygen affinity haemoglobins, high levels of cooperative oxygen binding, the presence of multiple haemoglobins and the ability to aestivate and survive long periods of emersion. 

The four mainland Neochanna species were examined to determine if differences in haemoglobin expression as well as differences in haemoglobin oxygen binding correlated with differing habitats and treatments.  Whole blood oxygen affinity was determined at several pH levels (6.5, 7.0, 7.5 and 8.0) and temperatures (10'C, 15'C and 20'C), as well as different treatments (aestivating, fasting and control) using a Hemox analyzer.  The presence of multiple haemoglobins was determined by isoelectric focusing.  All four species displayed high oxygen affinities (p50 = 6.5 to 9.5 mm Hg at pH 7.5  15'C), moderate levels of cooperativity (Hill coefficients = 1.75 to 2.00 at pH 7.5  15'C), pH sensitivity (Bohr coefficients = -0.62 to -0.94 between pH 7.5 and 7.0 at 15'C), temperature sensitivity (ΔH = -2.20 to -15.78 k cal mol-1 between 10'C and 15'C) and the presence of multiple haemoglobins.  Black, brown and Northland mudfish were able to survive aestivation for six weeks but there were no changes between air-breathing and water-breathing individuals with respect to oxygen binding characteristics.  Although there is evidence of habitat specialization in haemoglobin physiology between mudfish species, differences between species did not correlate with the evolutionary series proposed for specialization to dwelling in ephemeral wetlands and latitudinal distributions of mudfish species appear to strongly dictate oxygen binding properties of mudfish whole blood.

year: 2007

title: Millions of random rules

authors: Pfahringer, Bernhard

subjects: computer science

abstract: In this paper we report on work in progress based on the induction of vast numbers of almost random rules. This work tries to combine and explore ideas from both Random Forests as well as Stochastic Discrimination. We describe a fast algorithm for generating almost random rules and study its performance. Rules are generated in such a way that all training examples are covered roughly by the same number of rules each. Rules themselves usually have a clear majority class among the examples they cover, but they are not limited in terms of either minimal coverage, nor minimal purity. A preliminary experimental evaluation indicates really promising results for both predictive accuracy as well as speed of induction, but at the expense of both large memory consumption as well as slow prediction. Finally, we discuss various directions for our future research.

text: Millions of random rules In this paper we report on work in progress based on the induction of vast numbers of almost random rules. This work tries to combine and explore ideas from both Random Forests as well as Stochastic Discrimination. We describe a fast algorithm for generating almost random rules and study its performance. Rules are generated in such a way that all training examples are covered roughly by the same number of rules each. Rules themselves usually have a clear majority class among the examples they cover, but they are not limited in terms of either minimal coverage, nor minimal purity. A preliminary experimental evaluation indicates really promising results for both predictive accuracy as well as speed of induction, but at the expense of both large memory consumption as well as slow prediction. Finally, we discuss various directions for our future research.

year: 2004

title: An exploration of different outlooks on science: towards an understanding of the under-representation of girls, and of Maori and Pacific Island students, in science

authors: Stead, Keith Eric

abstract: The research reported here was undertaken as a supplementary study to the Learning in Science Project conducted at Waikato University (1979-1981) and sought to understand why girls, Maori and Pacific Island students, are under-represented in the sciences. Two distinctive, but complementary, perspectives were developed; one qualitative, the other quantitative, to provide data from which an understanding of the problem was sought.
The qualitative perspective was provided by using a Kelly Repertory Grid methodology and intensive individual interviews with 26 students (and many of their parents) carefully chosen to provide a reasonably heterogeneous sample of students from a variety of different schools, of both sexes, of the three major ethnic groups (European, Maori, and Pacific Island), and from each of the four middle-school form levels (Fl to F4, inclusively).
The quantitative perspective was provided by a series of empirical measures chosen, not only to identify the students for the qualitative sample but also, to investigate particular variables suggested by the literature search to have possible implications for the teaching and learning of science. 
The resultant analyses suggested the sex differences in the students’ outlooks on science could be accounted for by the existence of a broad based ‘gender-related inequality’ in the way science is presented to them by the communication media, home, and school.
Similarly, the ethnic differences in students’ outlooks on science could be accounted for by the ‘cultural inequality’ present in New Zealand society which was identified in the way many of the Polynesian students and their parents, perceived the products, processes, and practitioners of science. 
The simplification presented here masks the complexity of the issues involved but, series of educational within these two broad postulates, a series of educational recommendations was suggested for affecting current educational practices identified as maintaining (or even creating) the existing under-representation of girls, Maori and Pacific Island students in the sciences. 
These included:
(i) Student beliefs about science need to be explored, challenged, modified, and/or extended
(ii) Students’ perceptions of other people’s views need to be identified, explored, challenged and/or extended 
(iii) Teachers’ styles of teaching science need to be examined
(iv) Parents’ own outlooks on science need to be developed.
This research has emphasised the need to have all students, but particularly girls, Maori, and Pacific Island students, develop positive outlooks on science in order that the current imbalance of girls and Polynesians in the sciences be redressed.

text: An exploration of different outlooks on science: towards an understanding of the under-representation of girls, and of Maori and Pacific Island students, in science The research reported here was undertaken as a supplementary study to the Learning in Science Project conducted at Waikato University (1979-1981) and sought to understand why girls, Maori and Pacific Island students, are under-represented in the sciences. Two distinctive, but complementary, perspectives were developed; one qualitative, the other quantitative, to provide data from which an understanding of the problem was sought.
The qualitative perspective was provided by using a Kelly Repertory Grid methodology and intensive individual interviews with 26 students (and many of their parents) carefully chosen to provide a reasonably heterogeneous sample of students from a variety of different schools, of both sexes, of the three major ethnic groups (European, Maori, and Pacific Island), and from each of the four middle-school form levels (Fl to F4, inclusively).
The quantitative perspective was provided by a series of empirical measures chosen, not only to identify the students for the qualitative sample but also, to investigate particular variables suggested by the literature search to have possible implications for the teaching and learning of science. 
The resultant analyses suggested the sex differences in the students’ outlooks on science could be accounted for by the existence of a broad based ‘gender-related inequality’ in the way science is presented to them by the communication media, home, and school.
Similarly, the ethnic differences in students’ outlooks on science could be accounted for by the ‘cultural inequality’ present in New Zealand society which was identified in the way many of the Polynesian students and their parents, perceived the products, processes, and practitioners of science. 
The simplification presented here masks the complexity of the issues involved but, series of educational within these two broad postulates, a series of educational recommendations was suggested for affecting current educational practices identified as maintaining (or even creating) the existing under-representation of girls, Maori and Pacific Island students in the sciences. 
These included:
(i) Student beliefs about science need to be explored, challenged, modified, and/or extended
(ii) Students’ perceptions of other people’s views need to be identified, explored, challenged and/or extended 
(iii) Teachers’ styles of teaching science need to be examined
(iv) Parents’ own outlooks on science need to be developed.
This research has emphasised the need to have all students, but particularly girls, Maori, and Pacific Island students, develop positive outlooks on science in order that the current imbalance of girls and Polynesians in the sciences be redressed.

year: 1984