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Some amorphous constituents of New Zealand soils
Get PDFPart 1 – Allophanes derived from volcanic ash
Soils formed on weathered volcanic ash in the central and northern North Island of New Zealand contain the amorphous aluminosilicate allophane as the predominant clay mineral which is produced by the weathering of volcanic glass. Allophane has a characteristic DTA curve and I.R. spectrum which serve as a useful means of identifying the clay mineral.
Fine clays were separated from soils in the Waikato area and these showed typical allophane patterns of variable cation exchange capacity as well as DTA and I.R. spectra. Under the electron microscope these clays presented a picture of very small, ill-defined particles with indistinct edges and it was apparent that most of the properties of allophane could be explained by the presence of a colloidal system.
The colloidal properties of allophane were investigated and it was shown to be remarkable among clay minerals in having a high isoelectric point (∼6). This means that allophane is positively charged under normal soil pH’s (4.5 – 5.5). Synthetic aluminosilicates were prepared with varying SiO₂/Al₂O₃ ratios and it was found that with a SiO₂/Al₂O₃ ratio between 2 and 1.5 the isoelectric point was in the range 4.5 - 5.0. Increasing the ratio resulted in a lowering of the isoelectric point. If the allophane samples were deferrated using sodium dithionite and sodium citrate then the isoelectric point of the resulting material was below 2. The very high chemical reactivity normally associated with allophane was thus reduced, although the general properties such as the NaF/phenolphthalein teat and I.R. spectra were unaffected. The results show that the ferric oxide, despite its small proportion, contributes significantly to the high isoelectric point of the allophane found in natural soils.
A definition for allophane is proposed which includes its remarkable properties of high isoelectric point, high surface area, high ion exchange capacity along with its very high phosphate retention.
The presence of imogolite was noted in New Zealand soils for the first time in one sample.
Since New Zealand has a cheap, abundant supply of this unusual material, work was initiated to find possible commercial uses for allophane. One possible use described is the removal of protein from slaughterhouse effluent. The main proteins found in slaughterhouse effluent, hemoglobin, serum albumin and gelatin, were adsorbed onto allophane and adsorption isotherms determined for each. Allophane adsorbed up to 10% by weight of protein from a solution with the protein concentration of the order 1 mg/ml, after which the clay became saturated and would adsorb no further protein. At this stage the protein-clay complex became “jelly-like” and sank to the bottom of the flask. The actual amount of uptake was dependent on the particular allophane used and the solution pH.
Allophane shows indications of having antibiotic properties. The breakdown of protein by bacterial activity was greatly inhibited by the presence of allophane in the protein solutions. These solutions could be left open to the air for several days without any change in protein concentration measured by U.V. absorption. Also, when samples of allophane were examined under the electron microscope there were no signs of bacteria, unlike samples from non-volcanic soils in which bacteria could be readily seen. This phenomenon appears coupled with the fact that allophane from volcanic areas bears a positive charge at a pH less than about 6. The bacteria, being negatively charged, become surrounded by a coating of minute allophane particles which inhibits growth.
Part II – Synthetic aluminosilicates
Synthetic aluminosilicates were prepared to investigate the colloidal properties of alumina and silica. Positively charged hydrated alumina will adhere to the negatively charged surface of freshly cleaved mica and will readily absorb phosphate from a solution containing ³²P phosphate. Negatively charged hydrated silica was adsorbed onto the surface of alumina-treated mica. This would be expected to block the alumina to phosphate uptake, but this was not the case, the uptake being only slightly less than the alumina treated mica. If further alumina was added, little difference in phosphate uptake was again noted suggesting a uniform surface is presented to the phosphate solution. With hydsrated ferric oxide and hydrated silica alternately adsorbed on the mica surface, an oscillating pattern was noted showing that layers can be built up. The experiment was repeated using ⁵⁹Fe to ensure that layers were built up and not being removed and then replaced. These experiments showed that amorphous hydrous silica and alumina will react in some way and it is suggested that a reaction takes place between the colloidal hydrous aluminia and silica with the formation of Al-O-Si bonds. The ferric oxide system does not however for Fe-O-Si bonds, but it is suggested the colloidal particles are held together by electrostatic bonds in a form of “colloid complex”.
Fresh colloidal suspensions of hydrated alumina and silica prepared from hydrolysis of corresponding organo-derivatives, when mixed and freeze dried, provided an amorphous product with the properties or allophane. But if the solutions were allowed to age by standing tor several days, mixed and then freeze dried, the DTA pattern and X-ray spectrum showed the presence of bayerite (a crystalline form of Al(OH)₃). Addition of acid or base to the hydrolysing solutions increased the rate of crystallisation of hydrated aluminia to either bayerite or gibbsite.
Part III – Investigation of other “allophane-like” clay minerals
An allophane-like clay mineral has been reported by the pedologists in the High Country soils of the South Island of New Zealand. These soils have been derived from greywacke. In this thesis an attempt was made to bridge the gap between the pedological and chemical description of these soils.
Pedologists place great stock by the feel of a soil when it is rubbed between the fingers. When investigated it was found that it was the presence of amorphous oxides or materials less than 10⁻⁵cm that produces a slippery, non-sticky feel, usually associated with the presence of allophane. These High Country soils give this characteristic test and on this basis have been thought to contain allophane. The fine clays from both these soils, and the soils derived from chlorite-schist under similar climatic conditions, were separated and investigated. The soil properties of cation exchange, phosphate retention as well as the I.R. spectra, DTA curves and chemical composition were determined. These soils all gave a positive NaF/phenolphthalein test and up to 30% of the fine clay dissolved in boiling 0.5 M NaOH. However the DTA pattern showed a large additional exotherm and an additional endotherm which are not characteristic of allophane derived from volcanic parent material.
The electron micrographs showed the fine clays to be sharp, well-defined particles. Rocks taken from the soil and finely ground in a Tema Mill, showed similar properties. The samples were high in silica and had isoelectric points around three which means the particles bear a negative charge in soil under most field conditions. These results showed the clays to be less reactive chemically than volcanic allophanes.
A mechanism of soil formation is proposed whereby the rock is first split by ice-wedging and the pieces further ground by solifluction processes to produce very finely divided rock. The ground rock contains two X-ray amorphous components. One is micro-crystalline whose size is too small to diffract X-rays or to produce an I.R. pattern, and which can only be studied by DTA and electron microscopy. The only weathering that has taken place in this component is the oxidation of much of the iron from ferrous to ferric and a certain amount of leaching. The second component is rock whose original crystal lattice has been destroyed and so it is truly amorphous having a random structure.
It is proposed that these amorphous fractions may be a common soil constituent in alpine and polar regions. This material, which it is proposed is a variation of allophane, is given the name “Alpinite”. “Alpinite” will usually weather to the more usual clay minerals. Under periglacial conditions, however, the rate of formation is high and the rate of transformation to other clay minerals is low so that a high steady state concentration is reached. So high that sample of the fine clays (< 0.2μ) from soils derived at high altitudes give no X-ray pattern whatsoever
Performance at the cost of well-being? Testing the multi-level effects of HR practices on organisational performance via employee experiences and well-being
Get PDFPurpose
While the potential for HR practices (HRPs) to improve organisational performance is well-established, the mechanisms by which this occurs are complex. Individual HRPs may affect organisational performance either by mutual gains (improving both organisational performance and employee well-being) or by conflicting outcomes (organisational performance is improved at the expense of employee well-being). Models which combine HRPs may mask these differences and this study therefore tests pathways for four individual HRPs.
Design/methodology/approach
HRPs (employee involvement, pay, performance management and training) were hypothesised to influence organisational performance directly and indirectly via employee experiences of work (communication, autonomy) and employee well-being. The study used a large secondary dataset, the UK Workplace Employee Relations Survey 2011, to test these relationships in a multi-level model.
Findings
Employee experiences of work strongly predicted well-being. In addition, three different pathways from HRP to organisational performance were identified. Pay showed indirect negative effects, involvement had direct positive effects and performance management had a mixture of both positive direct and negative indirect effects on performance.
Originality/value
Using a disaggregated analysis of HRP and demonstrating their differing effects, this study questions the feasibility of a universal model of HRP effects. By using multi-level modelling (MLM), the study develops understanding of employee perspectives and integrates these into organisational-level models, demonstrating that performance effects are partially mediated by both employee experiences of work and employee well-being. Finally, the study highlights the complexity of performance effects achieved via both employee benefits and an intensification of employee experiences
Machine learning approaches for malware classification based on hybrid artefacts
Get PDFMalware could be developed and transformed into various forms to deceive users and evade antivirus and security endpoint detection. Furthermore, if one machine in the network is compromised, it could be used for lateral movement--when malware spreads stealthily without sending an alarm to monitoring systems. Malware attacks pose security threats to modern enterprises and can cause massive financial, reputation, and data loss to major enterprises. Therefore, it is important to detect these attacks effectively to reduce the loss to the minimum level. The current research uses different approaches, including static and dynamic analysis, to detect and analyze malware categories using distinct feature sets, such as imported modules, opcodes, and API calls, which can improve performance in binary and multi-class classification problems.
This thesis proposes a method for identifying and analyzing malware samples via static and dynamic approaches, including memory analysis and consecutive application operation sequences performed on the Windows 10 virtual environment. Standard classifiers and frequently used sequence models are utilized to expose the malware characteristics and benefit predictive capabilities. The features used in these algorithms are extracted from the static and dynamic analysis of malware samples, such as the rich header feature, debug information, temporary files, prefetch files, and event logs. The measurement of the classifiers and the degree of correctness are calculated using the accuracy, f1-score, Mean Absolute Error (MAE), confusion matrix, and Area under the ROC Curve (AUC). Combining two feature sets can provide the best classification performance on static file properties and dynamic analysis results, regardless of whether applying feature selection or not, achieving the accuracy and f1_score at 97% for integrating two datasets. For consecutive sequences, concatenating the Gated Recurrent Unit (GRU) and Transformers model can yield the highest accuracy at 97% for Noriben operations, while GRU can achieve the maximum accuracy for Opcode sequences at 89%
The quantum theory of optical bistability in nonlinear systems
Get PDFThis thesis is concerned with the investigation of the behaviour of various nonlinear systems when excited by a coherent light-field.
Of particular interest to us is the possibility of observing optical bistability in these systems.
In Chapter One we introduce the general theoretical methods we employ to perform all investigations.
In Chapters Two and Three we develop a quantum theory of the interaction of light with a variety of different systems, i.e. Raman active media, the parametric oscillator, the two-photon absorber and a system of three-level atoms.
In each case, a master equation, containing all statistical information about the system, is derived. This enables the systematic inclusion of a damping mechanism into each model.
Discussion is limited to the steady state behaviour of the systems, and in general we assume the deterministic limit in which we ignore quantum fluctuations in the field variables. It is then possible to factorise the steady state expectation values of these variables.
Steady state calculations indicate that each system may exhibit optical bistability in output field/intensity dependent on input field/intensity.
To determine whether a system will display optical bistability, it is necessary to perform a stability analysis. Where possible, such analytical calculations are performed. However, in certain cases the complexity of the highly nonlinear systems results in these calculations becoming extremely difficult. In such cases, conclusions relating to the stability of the system are drawn from graphical plots of its steady state behaviour.
Chapters Four to Eight are devoted to a study of the intracavity interaction of coherent radiation with semiconductors.
As explained in Chapter Four (of an introductory nature), this work was prompted by two recent experiments which indicated the existence of optical bistability in semiconductors. Although both experiments used semiconductors as the nonlinear material, the mechanism proposed to produce the observed bistability in each case was vastly different.
In Chapter Eight we discuss one of these mechanisms – interband excitation. We present a very simple theory of this effect and show that in essence it is equivalent to the theory of optical bistability in two-level systems. However, we stress that our theory is only approximate and relies on the validity of several simplifying assumptions.
Chapters Five and Six concern the other form of semiconductor optical bistability - arising from the interaction between a light field and excitons comprising the semiconductor.
In order to develop a quantum theory of this system using master equation techniques, it is necessary to transform the fermion system to a boson system. Bosonisation transformations required to effect this are developed in Chapter Five.
In Chapter Six we present a fully quantum mechanical theory of optical bistability in excitonic systems. Two types of bistability are found: bistability in output intensity and also exciton number, dependent on input intensity.
In Chapter Seven we investigate the effects of quantum fluctuations in a low density exciton system, by considering its Fokker-Planck equation. We discuss in detail the adiabatic elimination of stochastic variables with regard to the system’s Fokker-Planck equation
Copyright in education: bringing the classroom to life
Get PDFThe author, the daughter of a refugee, underscores the significance of education instilled by her father, who lacked it himself but saw it as a means to break free from poverty. She argues that educators require affordable training and access to materials, but copyright laws create obstacles.
Research highlights issues with copyright exceptions for educators in Fiji and the Philippines. Educators unintentionally use copyrighted materials, struggling with the intricacies of copyright law.
Financial limitations pose challenges for educational institutions globally, impacting both developed and developing countries. Educators often resort to using online resources without proper licensing due to these constraints.
The author stresses the concern of copyright enforcement against educators, particularly in developing nations. Complex copyright exceptions hinder teaching quality and material utilization.
In conclusion, the author urges a relaxation of copyright laws in education to ensure equitable access to education, especially in developing countries
'He is a gentleman. I am a gentleman’s daughter. So far we are equal’: Gender performance in twenty-first century adaptations of Jane Austen’s Emma and Pride and prejudice
Get PDFThe core focus of this thesis is gender performance in two of Jane Austen’s novels, Pride and Prejudice and Emma, and twenty-first-century adaptations of these novels. The thesis revolves around six key texts: Austen’s novel Pride and Prejudice, its 2005 film adaptation of the same name directed by Joe Wright, and the transmedia modernisation, The Lizzie Bennet Diaries; as well as Austen’s novel Emma, its 2020 film adaptation of the same name directed by Autumn de Wilde, and the transmedia web series, Emma Approved. There have undoubtedly been shifts in gender performance over the two hundred years since Austen published her novels, but these are not always reflected in the adaptations. In part this is due to the surprisingly progressive nature of some of Austen’s meditations on gender, with Elizabeth Bennet from Pride and Prejudice presenting as a pre-feminist and George Knightley from Emma performing as a pre-feminist man. These aspects of gender performance are extended by Keira Knightley’s portrayal of Elizabeth Bennet in Wright’s film, which reframes the character as a Romantic feminist, and Johnny Flynn’s performance of Mr. Knightley as a hero positioned under the female gaze in de Wilde’s film.
Yet, the thesis also reveals that Austen’s feminist precursors are not always developed in contemporary adaptations. Indeed, Lizzie Bennet in The Lizzie Bennet Diaries is a postfeminist who is far from being an autonomous twenty-first century woman and is dependent on family and male suitors to provide her with opportunities. Likewise, the opportunity to reimagine Austen’s characters in a twenty-first-century gender context is also ignored in some adaptations, particularly the transmedia web series, with Emma in Emma Approved continuing to endorse patriarchal structures in the same way that she does in Austen’s original novel. The dandyism of Frank Churchill in Austen’s Emma is also undercut in Emma Approved through a performance of heteronormativity that sidelines the queer potential initiated by previous adaptations, such as the 1995 film Clueless. Most striking is the stagnant gender performance of Mr. Darcy from Pride and Prejudice who remains the embodiment of hegemonic gentry masculinity in both the film and the web series. This thesis reveals that the lack of change in gender performance in some contemporary Austen adaptations demonstrates the persistence of hegemonic masculinity in the twenty-first century, while postfeminist performances of gender at times seem regressive
Work-family responsibilities and support for women academics in Pakistan
Get PDFGlobally women have a long history of negotiating between public and private life. While each individual woman undertakes such negotiation, all women’s lives are already shaped by historical, political, religious and cultural forces. This study focused on contemporary academic women in Pakistan and their experiences of negotiation between professional and family responsibilities – in an Islamic nation, shaped by an imperial history. In particular it investigated both the possibilities and limitations of family and institutional support as women worked to fulfil both work and family responsibilities.
This qualitative study employed semi-structured interviews, with individuals from three groups: women academics, husbands of women academics, and heads of department of two Pakistani universities. The data from these interviews were then read alongside selected theory, to produce accounts of the visible and invisible discourses shaping the positions available to women as they navigate family and career responsibilities. The study’s findings show that patriarchal traditions that position men as breadwinners and women as homemakers are disturbed when women take up career opportunities in academia, at the same time as patriarchal gender practices rob women of opportunities they have earned, as in examples of a woman giving up a job offer in favour of her husband, or giving an academic husband financial support for publication. As a further example of contesting discourses, the study identifies that academic women are expected to be productive on the terms of globalised neo-liberal education at the same time as a traditional school curriculum and teaching practices position educated women - parhi likihi- as responsible for the basics of their children’s learning within the home. Academic women are caught in the tension between the expectations of globalised tertiary education and the reality of the limited material resources in universities in a developing country. The analysis of women academics’ accounts of family support includes few but significant examples of disturbing and resisting patriarchal gender practices, in ways that the thesis argues contribute to a “democracy to come”. However, for the most part, the narratives of support include women academics’ husbands’ limited contributions and stories of women academics’ struggles, compromises and sacrifices of their own career progression for their husbands’ careers. The thesis argues that identifying the possibilities of questioning and undoing patriarchal gender practices and producing alternative discursive practices might open up possibilities for gender justice within family and academic institutions
Who does external quality assurance policy in Sāmoa serve, and who benefits?
No full textQuality assurance has been described as the single most significant policy to have emerged in the higher education sector in recent times. This research critically examines the question of who is served by external quality assurance policy for higher education in Sāmoa through an examination of the voices and values that determine policy, how these shape policy relationships and how academics respond to external quality assurance policy.
The conceptual framework for this research draws firstly on Kabini Sanga’s (2004) conceptualisation of indigenous Pacific research as having particularities in terms of ontology, epistemology, axiology, and methodology, secondly on aspects of critical realist theory; and subsequently on elements of postcolonial critique and critical policy studies. This research used thematic analysis and an emergent analytical and contextually relevant tool to interpret the research findings.
The findings indicate firstly that four groups of policy actors influence decision-making on external quality assurance policy in Sāmoa. These groups include quality assurance policy officials as agents of the government, international consultants, university and academic leaders, and transnational quality assurance networks. Consultants and transnational quality assurance networks make up an influential part of the epistemic community that shapes how quality assurance policy officials think about quality assurance in higher education.
Secondly, the ideal of international recognition and neoliberal management principles such as effectiveness, efficiency, compliance and accountability underpin Sāmoa’s external quality assurance policy, which is also marked by an absence of Sāmoa’s cultural values. The close connection to skills and employment as a driver of neoliberal economic growth is apparent in Sāmoa’s external quality assurance policy documents. This research suggests that the valorisation of the neoliberal values of effectiveness, efficiency, compliance and accountability in Sāmoa’s external quality assurance policy results in a hegemonic, disconnected and transactional relationship between the government and the university.
Academics responded in various ways to external quality assurance policy. Their responses ranged from resistance to resignation to acceptance and affirmation. The reasons for acceptance by academics included the attraction of funding support, local and international recognition of qualifications, the perceived marketability of quality-assured status, and a sincere desire to improve the quality of their work. The reasons for resistance were influenced by a myriad of factors that can be categorised into relational aspects and value factors.
The findings of this research suggest that external quality assurance policy for higher education in Sāmoa is primarily enacted to drive economic growth through efficient and effective skills development and the aspirational purposes of obtaining a better life for Sāmoan people through international and local recognition of higher education qualifications. Overall, it is not evident from this research that external quality assurance policy in Sāmoa serves the purpose of enhancing teaching and learning in higher education.
The findings of this research have implications for how education policymakers in Sāmoa conceptualise policy solutions for quality higher education. This research directs attention to the need to conceptualise policy solutions that are framed within indigenous Sāmoan notions of quality and service for the Sāmoan people. Secondly, there are implications for considering alternative policy approaches that do not rest on neoliberal market principles but focus on social justice. Thirdly there are implications for rethinking the unrelenting drive for international recognition of Sāmoa’s qualifications in view of the discussion on the subsequent hegemony and disconnectedness between those who work in higher education and those who make policy decisions about higher education quality in Sāmoa
Causal attributions for marital separation
Get PDFThe main purpose of this study was to analyse the structure and content of real-life causal attributions, using this data to examine some important theoretical and empirical issues within attribution theory. Chapter one provides a justificatory backdrop to this research. It is argued here that this type of real-life exploratory research is sorely needed because the vast bulk of the attribution research has hitherto utilised a laboratory based experimental approach which has weak ecological validity.
The causal attributions examined came from free-response verbal protocols of explanations for marital separation. The sample comprised 29 males and 33 females, living in Hamilton, New Zealand, all of whom had been physically separated for less than 18 months. Two attribution taxonomies were developed to classify the attributions, both of which had adequate inter-rater reliability. One taxonomy was in terms of content attributions (e.g. communication, sex, etc.), while the other was an abstract taxonomy in terms of attitudes, personality characteristics, etc. The findings from these taxonomies, which included some interesting sex differences, are fully discussed.
The technique of subjective magnitude estimation (developed by S.S. Stevens within the field of psychophysics) was used by respondents to give causal importance weights to the attributions derived from the verbal protocols. Ratio-level data, representing perceived causal responsibility for different attribution targets (self, ex-spouse, external factors, etc.) were derived from these weights, and multiple regression tests were carried out to examine the impact exerted by a range of independent variables on these attribution category percentages. It was found that the most influence on these derived attribution percentages was exerted by which partner decided to leave, education level and personal control. There was also some evidence that attribution patterns were related to self-reported levels of coping. A range of evidence, including convergent validity and reliability correlations, is presented which supports the validity of using this technique for deriving ratio level data from verbal protocols.
The descriptive and other data gathered was found to be both consistent and inconsistent with different aspects of attribution theory. The major findings inconsistent with the extant theories, were the range and complexity of people’s explanations, and people’s tendency to make attributions for dispositions. Conversely, the data strongly supported the psychological validity of the internal-external distinction, and also supported attribution theory’s assumption that personal dispositions are the most important class of attribution.
A number of other empirical attribution issues are examined, the main ones being the self-serving defensive attribution model vs the information processing model and the question of where the causal attributions come from. In the former case it is argued that both models are supported by our data. In the latter case, it is concluded that, (a) there does exist a socially shared theory of what causes marriages to break up, (b) that separated people do not select their attributions by consulting this theory, and (c) that they do cognitively access this theory in the process of providing causal importance weights for the attributions.
A range of other findings is presented. For example, one finding of interest was that more females (64%) decided to leave the marriage than males (21%). In all cases explanations are proffered and discussed for the reported findings
Semi-Structured Interviews and Focus Groups
No full textA semi-structured interview is a verbal interchange where one person, the interviewer, attempts to elicit information from another person by asking questions. Although the interviewer prepares a list of predetermined questions, semi-structured interviews unfold in a conversational manner offering participants the chance to explore issues they feel are important. A focus group is a group of people, usually between 6 and 12, who meet in an informal setting to talk about a particular topic that has been set by the researcher. The facilitator keeps the group on topic but is otherwise non-directive, allowing the group to explore the subject from as many angles as they please. This chapter explains how to go about conducting both semi-structured interviews and focus groups whether they be in-person or online. These two methods share some characteristics in common but are distinct. They can be used separately or together. Our review traces some of the early work in contemporary geography that used these methods, especially from feminist perspectives, but also highlights recent scholarship to demonstrate the evolution and creative vibrancy of this work over time