title: Classification and discrimination of automotive glass using LA-ICP-MS

authors: Grainger, Megan N.C.

subjects: automotive glass

abstract: Glass is one of the most common types of trace evidence found at crime scenes and on suspects. The elemental analysis of float glass has become increasingly important as the range in values of refractive index has substantially narrowed due to increased quality control in glass manufacture. The purpose of this research was to investigate the variation of elements in automotive float glass relevant to New Zealand for the purpose of classifying and discriminating samples. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to analyse the elemental composition of 243 automotive glass samples. An intact side window (tempered pane) and an intact windscreen (laminated pane) were analysed to investigate the spatial trend of elements in automotive glass. Most elements displayed no spatial variation over the panes. Pb had the largest variation in the windscreen and was also found to have a large variation in the database. Most samples were able to be classified into the vehicles' country of origin using a multiclass classifier. However, this was not possible for all samples, due to the origin of glass differing from the origin of the vehicle in some cases. The elemental composition of Australian and Northern Hemisphere samples differed greatly making them easy to separate; however, there was little variation within the Australian samples, making it hard to discriminate between different samples. A three step method, which combined the use of elemental composition, △RI and RI, was used to discriminate database samples. The method distinguished 84% (172/204) of samples in the database. When Australian samples were removed from the analysis, the discrimination increased to 95% (148/156). The type II errors were reduced by using both elemental composition and RI measurement.

text: Classification and discrimination of automotive glass using LA-ICP-MS Glass is one of the most common types of trace evidence found at crime scenes and on suspects. The elemental analysis of float glass has become increasingly important as the range in values of refractive index has substantially narrowed due to increased quality control in glass manufacture. The purpose of this research was to investigate the variation of elements in automotive float glass relevant to New Zealand for the purpose of classifying and discriminating samples. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to analyse the elemental composition of 243 automotive glass samples. An intact side window (tempered pane) and an intact windscreen (laminated pane) were analysed to investigate the spatial trend of elements in automotive glass. Most elements displayed no spatial variation over the panes. Pb had the largest variation in the windscreen and was also found to have a large variation in the database. Most samples were able to be classified into the vehicles' country of origin using a multiclass classifier. However, this was not possible for all samples, due to the origin of glass differing from the origin of the vehicle in some cases. The elemental composition of Australian and Northern Hemisphere samples differed greatly making them easy to separate; however, there was little variation within the Australian samples, making it hard to discriminate between different samples. A three step method, which combined the use of elemental composition, △RI and RI, was used to discriminate database samples. The method distinguished 84% (172/204) of samples in the database. When Australian samples were removed from the analysis, the discrimination increased to 95% (148/156). The type II errors were reduced by using both elemental composition and RI measurement.

year: 2012

title: The Structure of the Oligomerization Domain of Lsr2 from Mycobacterium tuberculosis Reveals a Mechanism for Chromosome Organization and Protection

authors: Summers, Emma Louise

subjects: biology

abstract: Lsr2 is a small DNA-binding protein present in mycobacteria and related actinobacteria that regulates gene expression and influences the organization of bacterial chromatin. Lsr2 is a dimer that binds to AT-rich regions of chromosomal DNA and physically protects DNA from damage by reactive oxygen intermediates (ROI). A recent structure of the C-terminal DNA-binding domain of Lsr2 provides a rationale for its interaction with the minor groove of DNA, its preference for AT-rich tracts, and its similarity to other bacterial nucleoid-associated DNA-binding domains. In contrast, the details of Lsr2 dimerization (and oligomerization) via its N-terminal domain, and the mechanism of Lsr2-mediated chromosomal cross-linking and protection is unknown. We have solved the structure of the N-terminal domain of Lsr2 (N-Lsr2) at 1.73 Å resolution using crystallographic ab initio approaches. The structure shows an intimate dimer of two ß-ß-a motifs with no close homologues in the structural databases. The organization of individual N-Lsr2 dimers in the crystal also reveals a mechanism for oligomerization. Proteolytic removal of three N-terminal residues from Lsr2 results in the formation of an anti-parallel β-sheet between neighboring molecules and the formation of linear chains of N-Lsr2. Oligomerization can be artificially induced using low concentrations of trypsin and the arrangement of N-Lsr2 into long chains is observed in both monoclinic and hexagonal crystallographic space groups. In solution, oligomerization of N-Lsr2 is also observed following treatment with trypsin. A change in chromosomal topology after the addition of trypsin to full-length Lsr2-DNA complexes and protection of DNA towards DNAse digestion can be observed using electron microscopy and electrophoresis. These results suggest a mechanism for oligomerization of Lsr2 via protease-activation leading to chromosome compaction and protection, and concomitant down-regulation of large numbers of genes. This mechanism is likely to be relevant under conditions of stress where cellular proteases are known to be upregulated.

text: The Structure of the Oligomerization Domain of Lsr2 from Mycobacterium tuberculosis Reveals a Mechanism for Chromosome Organization and Protection Lsr2 is a small DNA-binding protein present in mycobacteria and related actinobacteria that regulates gene expression and influences the organization of bacterial chromatin. Lsr2 is a dimer that binds to AT-rich regions of chromosomal DNA and physically protects DNA from damage by reactive oxygen intermediates (ROI). A recent structure of the C-terminal DNA-binding domain of Lsr2 provides a rationale for its interaction with the minor groove of DNA, its preference for AT-rich tracts, and its similarity to other bacterial nucleoid-associated DNA-binding domains. In contrast, the details of Lsr2 dimerization (and oligomerization) via its N-terminal domain, and the mechanism of Lsr2-mediated chromosomal cross-linking and protection is unknown. We have solved the structure of the N-terminal domain of Lsr2 (N-Lsr2) at 1.73 Å resolution using crystallographic ab initio approaches. The structure shows an intimate dimer of two ß-ß-a motifs with no close homologues in the structural databases. The organization of individual N-Lsr2 dimers in the crystal also reveals a mechanism for oligomerization. Proteolytic removal of three N-terminal residues from Lsr2 results in the formation of an anti-parallel β-sheet between neighboring molecules and the formation of linear chains of N-Lsr2. Oligomerization can be artificially induced using low concentrations of trypsin and the arrangement of N-Lsr2 into long chains is observed in both monoclinic and hexagonal crystallographic space groups. In solution, oligomerization of N-Lsr2 is also observed following treatment with trypsin. A change in chromosomal topology after the addition of trypsin to full-length Lsr2-DNA complexes and protection of DNA towards DNAse digestion can be observed using electron microscopy and electrophoresis. These results suggest a mechanism for oligomerization of Lsr2 via protease-activation leading to chromosome compaction and protection, and concomitant down-regulation of large numbers of genes. This mechanism is likely to be relevant under conditions of stress where cellular proteases are known to be upregulated.

year: 2012

title: Decolonising legal research: Developing legal theory to articulate Māori and non-Māori legal research paradigms equitably

authors: Hasan-Stein, Linda

abstract: Māori and non-Māori legal research paradigms in Aotearoa New Zealand are separated by a considerable theoretical knowledge gap. Māori knowledge systems are generally not well known in a non-Māori context. In order to bridge this theoretical knowledge gap jurisprudential studies need to address this gap from Māori and non-Māori perspectives. Doing so enables the development of decolonised legal research paradigms which allow for the sharing of knowledge from positions of respect. In this work, a new theoretical interpretation of legal research paradigms in our jurisprudence is presented, relying on an interdisciplinary approach to support these interpretive strategies. 

Beginning with the understanding that knowledge is empowering for both Māori and non-Māori, I foreground the epistemological character of decolonising legal research that supports Linda Tuhiwai Smith’s call for research to be conceived differently and highlight the need for an integrated recognition of kaupapa Māori in the development of legal theory in Aotearoa New Zealand. Reimagining our laws as something more than ‘sovereignty’ is the first step in narrowing the current theoretical knowledge gap. I translate the broader language of colonialism into the more specific vocabulary of the criminal justice system, in order to make more visible the manner in which Eurocentrism permeates decolonising legal research and stifles the potential future social development of Māori. 

Since Linda Tuhiwai Smith’s call to decolonise research, significant progress has been made with regard to the inclusion of principles of tikanga Māori to guide legal research that includes Māori. However, transforming principles of tikanga Māori into our jurisprudential landscape is a complex task. It is increasingly recognised that understanding the key principles of tikanga Māori is not always sufficient and that a greater theoretical understanding of decolonising legal principles is needed. I will analyse theoretical features of research epistemologies with the goal of grasping the complex array of historically-specific practices through which particular dimensions of our socio-legal experience are produced. 

Finally, I will explore how an interdisciplinary approach enables us to link forms of subjectivity to forms of objectivity in a distinctively “cultural” way, by working through difference rather than against it, and by acknowledging as meaningful each law’s characteristic discursive formation. 

This work is written as an intervention in Eurocentrism, aimed at providing a fresh interpretation of decolonising legal research. On this level, the most important argumentative thread is the one that demonstrates how Eurocentrism can be read as a colonising tool, which deploys positions that marginalise Indigenous knowledge. By unpacking Eurocentrism’s complex meaning it is possible to refashion Eurocentrism to include the notions of “partnerships”, that value subjective experience over objective, and that, in reality, include “Indigenous cultural” qualities. 

This style of decolonising jurisprudence pushes strenuously for a legal paradigm shift towards a culturally safe space for all legal scholars, not just Māori; a shift that could encourage our legal theory to converge in a more holistic way. The most important argumentative threads are those centred on the inclusion of Indigenous arguments, and the emergent character of decolonising legal research categories such as whanaungatanga or relational accountability. This type of innovative legal interpretation offers the possibility for a new theoretical era for decolonising legal research.

text: Decolonising legal research: Developing legal theory to articulate Māori and non-Māori legal research paradigms equitably Māori and non-Māori legal research paradigms in Aotearoa New Zealand are separated by a considerable theoretical knowledge gap. Māori knowledge systems are generally not well known in a non-Māori context. In order to bridge this theoretical knowledge gap jurisprudential studies need to address this gap from Māori and non-Māori perspectives. Doing so enables the development of decolonised legal research paradigms which allow for the sharing of knowledge from positions of respect. In this work, a new theoretical interpretation of legal research paradigms in our jurisprudence is presented, relying on an interdisciplinary approach to support these interpretive strategies. 

Beginning with the understanding that knowledge is empowering for both Māori and non-Māori, I foreground the epistemological character of decolonising legal research that supports Linda Tuhiwai Smith’s call for research to be conceived differently and highlight the need for an integrated recognition of kaupapa Māori in the development of legal theory in Aotearoa New Zealand. Reimagining our laws as something more than ‘sovereignty’ is the first step in narrowing the current theoretical knowledge gap. I translate the broader language of colonialism into the more specific vocabulary of the criminal justice system, in order to make more visible the manner in which Eurocentrism permeates decolonising legal research and stifles the potential future social development of Māori. 

Since Linda Tuhiwai Smith’s call to decolonise research, significant progress has been made with regard to the inclusion of principles of tikanga Māori to guide legal research that includes Māori. However, transforming principles of tikanga Māori into our jurisprudential landscape is a complex task. It is increasingly recognised that understanding the key principles of tikanga Māori is not always sufficient and that a greater theoretical understanding of decolonising legal principles is needed. I will analyse theoretical features of research epistemologies with the goal of grasping the complex array of historically-specific practices through which particular dimensions of our socio-legal experience are produced. 

Finally, I will explore how an interdisciplinary approach enables us to link forms of subjectivity to forms of objectivity in a distinctively “cultural” way, by working through difference rather than against it, and by acknowledging as meaningful each law’s characteristic discursive formation. 

This work is written as an intervention in Eurocentrism, aimed at providing a fresh interpretation of decolonising legal research. On this level, the most important argumentative thread is the one that demonstrates how Eurocentrism can be read as a colonising tool, which deploys positions that marginalise Indigenous knowledge. By unpacking Eurocentrism’s complex meaning it is possible to refashion Eurocentrism to include the notions of “partnerships”, that value subjective experience over objective, and that, in reality, include “Indigenous cultural” qualities. 

This style of decolonising jurisprudence pushes strenuously for a legal paradigm shift towards a culturally safe space for all legal scholars, not just Māori; a shift that could encourage our legal theory to converge in a more holistic way. The most important argumentative threads are those centred on the inclusion of Indigenous arguments, and the emergent character of decolonising legal research categories such as whanaungatanga or relational accountability. This type of innovative legal interpretation offers the possibility for a new theoretical era for decolonising legal research.

year: 2026