Automation of pollen analysis using a computer microscope : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Computer Systems Engineering at Massey University

The classification and counting of pollen is an important tool in the understanding of processes in agriculture, forestry, medicine and ecology. Current pollen analysis methods are manual, require expert operators, and are time consuming. Significant research has been carried out into the automation of pollen analysis, however that work has mostly been limited to the classification of pollen. This thesis considers the problem of automating the classification and counting of pollen from the image capture stage. Current pollen analysis methods use expensive and bulky conventional optical microscopes. Using a solid-state image sensor instead of the human eye removes many of the constraints on the design of an optical microscope. Initially the goal was to develop a single lens microscope for imaging pollen. In-depth investigation and experimentation has shown that this is not possible. Instead a computer microscope has been developed which uses only a standard microscope objective and an image sensor to image pollen. The prototype computer microscope produces images of comparable quality to an expensive compound microscope at a tenth of the cost. A segmentation system has been developed for transforming images of a pollen slide, which contain both pollen and detritus, into images of individual pollen suitable for classification. The segmentation system uses adaptive thresholds and edge detection to isolate the pollen in the images. The automated pollen analysis system illustrated in this thesis has been used to capture and analyse four pollen taxa with a 96% success rate in identification. Since the image capture and segmentation stages described here do not affect the classification stage it is anticipated that the system is capable of classifying 16 pollen taxa, as demonstrated in earlier research

Efficient holographic proofs

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 1996.Includes bibliographical references (p. 57-63).by Alexander Craig Russell.Ph.D

Spin-Filtering Multiferroic-Semiconductor Heterojunctions

We report on the structural and electronic properties of the interface between the multiferoic oxide YMnO$_3$ and wide band-gap semiconductor GaN studied with the Hubbard-corrected local spin density approximation (LSDA+U) to density-functional theory (DFT). We find that the band offsets at the interface between antiferromagnetically ordered YMnO$_3$ and GaN are different for spin-up and spin-down states. This behavior is due to the spin splitting of the valence band induced by the interface. The energy barrier depends on the relative orientation of the electric polarization with respect to the polarization direction of the GaN substrate suggesting an opportunity to create magnetic tunnel junctions in this materials system.Comment: 4 pages, 4 figure

The Parallax Gap

In post-conflict Northern Ireland, the artist Willie Doherty has been active in showing how the memory trace of the Troubles lingers on as a spectral presence. Doherty’s work has been influential to a number of visual artists working in response to this context, whose work can be characterized by a heightened sense of in-betweenness and representational, spatial, or temporal instability (Long, 2019). Such work is concerned with an oscillation between the past and the present in order to convey the sense of an uncertain future. Although filmic, photographic, and sculptural works have been deployed by such artists to harness these conditions of uncertainty, it is the medium of drawing that remains relatively under-explored as a way of showing how the specters of violent pasts remain in this fragile context. This paper is an examination in the use of drawing to show the spectral presence that continues to haunt spaces marred by histories of violence in Northern Ireland’s post-conflict context. The study is underpinned by theories that relate to haunting, but also to psychoanalysis, as read through Slavoj Žižek’s theory of the Parallax Gap. Theoretical concerns are applied to the filmic techniques of the artist Willie Doherty (2007), and to Richard Hamilton’s painting Trainsition IIII (1954). The resultant drawing and textual analysis responds to the spectral-turn in post-conflict art in Northern Ireland, making a case for drawing as a practice of haunting

Structural determinants and regulation of spontaneous activity in GABAA receptors

Rapid inhibition in the central nervous system predominantly occurs through the activation of GABAA receptors. These are anion-selective ligand-gated ion channels permeable to chloride ions, and activation typically results in the inhibition of neuronal activity through phasic and tonic mechanisms. Some GABAA receptor subtypes are capable of opening in the absence of GABA to contribute towards tonic inhibition, but the mechanism by which this occurs and the effect on neuronal activity is not well understood. A variety of recombinant GABAA receptor isoforms were examined for spontaneous activity by expression in HEK cells. Only those receptors containing the β3 subunit showed demonstrable levels of spontaneous activity, and key residues underpinning this were identified within the β3 extracellular domain. To investigate how spontaneous activity may be regulated in vivo, we examined phosphorylation of the β3 subunit using mutagenesis and by manipulating kinase activity, demonstrating a role for phosphorylation in regulating spontaneous current. Furthermore, the effect of various allosteric modulators, including neurosteroids, general anaesthetics and benzodiazepines, may exert a substantive part of their modulatory action through potentiation of spontaneous GABAA receptor activity. We demonstrate that the β3 subunit is also important for spontaneous activity of receptors expressed in hippocampal neurons in culture by both expressing subunits via transfection and by knock-down of native subunits using β3-selective shRNAs. Examination of hippocampal and thalamic areas in adolescent rat brain slices identified varying levels of spontaneous current contributing to tonic inhibition, consistent with variable expression of the β3 subunit. Finally, mutations of the β3 subunit linked with epilepsy were studied and found to impact on spontaneous currents. Overall, these data demonstrate the profound importance of the β3 subunit in controlling neuronal excitability, including the mechanisms by which neurons may alter levels of tonic inhibition through regulation of spontaneous GABAA receptor currents

Tracking Discourses of Occupation and Genocide in Lithuanian Museums and Sites of Memory

This thesis is dedicated to Hamish Alexander Douglas Wight – Always missed and very much loved.Tourism visits to sites associated to varying degrees with death and dying have for some time inspired academic debate and research into what has come to be popularly described as ‘dark tourism’. Research to date has been based on the mobilisation of various social scientific methodologies to understand issues such as the motivations of visitors to consume dark tourism experiences and visitor interpretations of the various narratives that are part of the consumption experience. This thesis offers an alternative conceptual perspective for carrying out research into museums that represent genocide and occupation by presenting a discourse analysis of five Lithuanian museums which share this overchig theme using Foucault’s concept of ‘discursive formation’ from ‘Archaeology of Knowledge’. A constructivist methodology is therefore applied to locate the rhetorical representations of Lithuanian and Jewish subject positions and to identify the objects of discourse that are produced in five museums that interpret an historical era defined by occupation, the persecution of people and genocide. The discourses and consequent cultural function of these museums is examined and the key finding of the research proposes that they authorise a particular Lithuanian individualism which marginalises the Jewish subject position and its related objects of discourse into abstraction. The thesis suggests that these museums create the possibility to undermine the ontological stability of Holocaust and the Jewish-Lithuanian subject which is produced as an anomalous, ‘non-Lithuanian’ cultural reference point. As with any Foucauldian archaeological research, it cannot be offered as something that is ‘complete’ since it captures only a partial field, or snapshot of knowledge, bound to a specific temporal and spatial context. The discourses that have been identified are perhaps part of a more elusive ‘positivity’ which is salient across a number of cultural and political surfaces which are ripe for a similar analytical approach in future. It is hoped that the study will motivate others to follow a discourse-analytical approach to research in order to further understand the critical role of museums in public culture when it comes to shaping knowledge about ‘inconvenient’ pasts

The development of the well-being interview

Although psychologists and psychotherapists have long been concerned with the construct of well-being, currently there exist only self-report measures of the construct. This is potentially problematic because, as a number of researchers have pointed out, there are many different kinds of biases that can undermine the validity of data obtained from self-report measures. The purpose of this project was to develop a comprehensive, user-friendly, clinician administered interview to assess well-being. In order to accomplish this, the Well-Being Interview (WBI) was developed, based on recent developments in positive psychology (e.g., Diener (2000), Ryff (1995) and Seligman (2011) and theoretical unification (Henriques, 2011). The WBI is a structured, clinician-administered assessment of well-being that evaluates well-being across ten different domains: Satisfaction, Engagement, Purpose, Health and Habits, Emotions, Relationships, Coping, Identity, Environmental Influences, and Trajectory. For each domain, individuals provide a narrative report reflecting on the domain, offer a quantitative rating, answer forced choice questions and are rated by the interviewer. Two hundred and fifty-eight participants filled out a series of self-report measures assessing a variety of constructs related to well-being online and a subset of fifty one subsequently participated in completing the WBI with trained evaluators. The measure performed well in terms of time of administration, comprehensiveness, and feasibility for use in clinical settings. Correlations with existing self-report measures were explored and future directions are discussed

Duodenal pH : new aspects of physiology and pathophysiology

The pathogenesis of duodenal ulcer is believed to centre around the presence of gastric acid, yet the exact role that acid plays is poorly understood. Previous investigations of the duodenal pH have been restricted by methodological and technical difficulties, and have, for the most part, only monitored the pH in the short-term. A new reliable system for long-term (twenty-four hour), ambulatory, simultaneous measurement of intra-luminal antral and duodenal bulb pH has been developed. The system comprises two glass pH electrodes, a small portable recording unit and a computer-based system for data storage and analyses. Validation of this pH monitoring system was first performed, and the 24-hour ambulatory profiles of antral and duodenal pH of normal healthy subjects were subsequently recorded. Periods of cephalic stimulation and ingestion of a solid meal were included during the study period. Having established the normal profiles, the investigation was repeated in patients with active duodenal ulcer, off-treatment. The gastric pH profile was similar of both study groups. There were no significant differences between the fasting duodenal bulb pH and the total 24-hour duodenal acid exposure of the ulcer patients and healthy subjects. Acid peak analysis demonstrated that the duodenal ulcer patients exhibited a defect in the propulsive duodenal bulb motility. Gastric stimulation caused a similar pattern of duodenal acidification in the two groups. These results suggest that gastric acid is not of primary pathophysiological importance in duodenal ulcer disease. The effects of cephalic stimulation and a meal on plasma gastrin, secretin and somatostatin and duodenal pH were examined in healthy subjects and duodenal ulcer patients. The results showed: vagally-released gastrin is not a significant contributor to stimulation of gastric acid secretion in either health or duodenal ulcer disease; duodenal ulcer patients have excessive basal and post-stimulation plasma gastrin levels but a subset of ulcer patients exists, the "Hypergastrinaemic" patients, who exhibit exaggerated gastrin responses, vagal hyperactivity, a defective somatostatin-induced inhibition of gastrin release and a defect in the "switch-off" mechanism of gastric acid secretion. In addition, the physiological role of secretin in inhibiting gastrin release in Man is questionable. This study reveals new aspects in the physiology and pathophysiology of the duodenal bulb pH