About MacSphere

MacSphere is McMaster University's Institutional Repository (IR). The purpose of an IR is to bring together all of a University's research under one umbrella, with an aim to preserve and provide access to that research. The research and scholarly output included in MacSphere has been selected and deposited by the individual university departments and centres on campus.

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Recent Submissions

The Effect of Agrochemicals and E-waste on Adverse Pregnancy Outcomes: A Methodological Review of Systematic Reviews
(2026) Ahmed, Shakil
Background: Exposure to environmental toxicants remains a critical global public health challenge, particularly during pregnancy, when maternal and fetal systems are uniquely vulnerable. Two major and increasingly prevalent sources of environmental contamination are agrochemicals, including pesticides and chemical fertilizers and electronic waste (e-waste), which commonly includes heavy metals, brominated flame retardants, and persistent organic pollutants. A growing body of research suggests that exposure to these substances may increase the risk of adverse pregnancy outcomes (APOs). However, the methodological quality and reporting standards of systematic reviews in this area are insufficient, which detracts from the reliability of existing conclusions. This uncertainty limits the reviews' effectiveness in informing policy decisions, clinical guidance, and risk communication. Objective: This methodological review aimed to systematically identify and evaluate the methodological and reporting quality of systematic reviews and meta-analyses examining the association between exposure to agrochemicals or e-waste and adverse pregnancy outcomes. The review further sought to compare statistical synthesis approaches used across meta-analytic reviews and identify methodological gaps to inform future research practice. Methods: This review followed the PRIOR (Preferred Reporting Items for Overviews of Reviews) reporting guideline. Two PROSPERO-registered protocols were developed a priori: one focused on agrochemical exposures (CRD42024533969) and one on e-waste exposures (CRD420250627366). Eight international bibliographic databases were searched without language or date restriction. Systematic reviews and meta-analyses reporting pregnancy-related clinical outcomes following exposure to agrochemicals or e-waste were eligible. Data extraction was performed independently by two reviewers. Methodological quality was assessed using AMSTAR-2. The completeness and transparency of search strategies were evaluated using the PRESS guideline and an operationalized reporting checklist developed by Norling et al. For reviews conducting meta-analysis, statistical methodology was assessed using a structured framework based on contemporary meta-analytic best practice. Results: A total of 39 systematic reviews were included: 27 on agrochemical exposures and 12 on e-waste-related toxicants. Across both exposure domains, the majority of reviews were rated as “critically low” quality according to AMSTAR-2, largely due to recurring critical weaknesses, including lack of prospective protocol registration, incomplete justification for excluded studies, and limited incorporation of risk-of-bias assessments into interpretation. Only a small proportion of reviews met high methodological standards. Evaluation of search strategy rigour showed moderate adherence to PRESS recommendations, although use of proximity operators, controlled vocabulary expansion, and search peer review were inconsistently applied. Reporting quality of search strategies also varied substantially, with incomplete documentation of databases, search dates, citation searching, and deduplication procedures in many reviews. Meta-analytic practices were heterogeneous, with frequent use of random-effects models but limited justification for model choice and variable assessment of heterogeneity and publication bias. Conclusions: This methodological review shows that most systematic reviews examining the impacts of agrochemical and e-waste exposure on adverse pregnancy outcomes have significant methodological and reporting limitations. These weaknesses reduce confidence in existing pooled estimates and limit the interpretability of findings for clinical, research, and policy decision-making. Strengthening future evidence synthesis in this field will require routine protocol registration, comprehensive and peer-reviewed search strategies, and standardized adverse pregnancy outcome definitions.
From Exposure to Understanding: How Cognitive and Linguistic Factors Shape L2 Vocabulary Learning in Digital Environments
(2026) Gallant, Jordan; Kuperman, Victor; Cognitive Science of Language
This thesis investigates the cognitive and linguistic factors that influence second-language (L2) vocabulary and morphological learning in app-based digital environments. Across three studies, I examine how exposure type, morphological structure, semantic transparency, and learners’ L1 backgrounds shape English vocabulary acquisition and morphological abstraction. The first study focused on incidental L2 vocabulary learning within a cloze-translation task, distinguishing between target encounters (when a word is explicitly practiced) and context encounters (when it appears indirectly). Results indicated that context encounters facilitated learning even during initial target exposures, though gains from incidental learning were smaller than those from explicit practice, highlighting the role of cognitive load and task difficulty in vocabulary acquisition. The second study investigated how L2 learners acquire morphological knowledge through app-based vocabulary training, examining the roles of repetition (token frequency), variability (type frequency), and semantic transparency. Successful morphological learning depended on repeated exposure to suffixes, particularly when they appeared in diverse lexical contexts, while non-morphemic sequences conferred no advantage. Type frequency emerged as a strong predictor of learning, and L1 background modulated performance: German-speaking learners, whose L1 shares morphological and typological similarities with English, showed substantial gains, whereas Japanese-speaking learners showed minimal improvement. The third study examined compound word learning, evaluating transparency at the whole-word and constituent (modifier and head) levels. Whole-word and head transparency consistently facilitated learning across language groups, while cross-linguistic differences emerged in sensitivity to modifier transparency, suggesting an interaction between universal semantic constraints and L1-specific processing strategies. Together, these studies demonstrate that L2 vocabulary and morphological learning are experience-driven, meaning-sensitive, and shaped by linguistic background. The findings advance theoretical models of lexical processing and provide evidence-based guidance for the design of adaptive, effective digital language-learning tools.
State Dependency and Long-Term Potentiation
(1991) Douglas Flint; Racine, R.J; Psychology
State-dependent learning (SDL) is the acquisition of behavioral outputs within specific environmental contexts. It is a robust phenomenon that has been demonstrated under a variety of conditions using both animal and human subjects. A number of environmental contexts or drug states have been shown to induce this effect. In the present study alcohol was used as the dissociating agent. The SDL effect was examined at the level of a monosynaptic neural circuit in the hippocampus of the rat. Long-term potentiation (LTP) was employed as a measure of SDL. LTP is the long-lasting enhancement of response strength following brief, high frequency activation, and has been used as a memory model. It has been well documented in monosynaptic systems particularly within the hippocampal circuitry as tested in this study. Although strong potentiation effects were not seen in all of the animals tested even those animals showing such effects showed no evidence for an SDL effect within the circuitry examined. The implications of this finding for future research is discussed
PUNISHMENT, LAW, AND PROPERTY IM THE POLITICAL PHILOSOPHY OF WILLIAM GODWIN
(1964-05) Edmon Feldman; Novak, D; Political Economy
The purpose of this study is to elucidate three aspects of Godwin's political thought against the background of his general philosophical position. The three aspects — punishment, law, and property — have been selected because of their continuing significance to contemporary discussions in political theory. These three aspects are all related and associated with political government; indeed, they represent the triumvirate of political power in modern society. Godwin's philosophical anarchism, which is based upon the ideal of bringing an egalitarian morality to bear upon political affairs, is a challenge to institutionalized political power. To Godwin, devotion to morality in the sense of genuinely disinterested behaviour was the sufficient condition for a just social order. The quest for justice or perfect society is not new. Godwin's quest, however, arising when the flames of the French Revolution had kindled in the minds of both its opponents and defenders a flurry of arguments, is, in its tone and pres entation, unique. The society which he proposes, based upon the individ ual's disposition to act according to what is just and proper (assuming that what is just and proper can be ascertained in every case), involves serious implications for the traditional concepts of punishment, law, and property. If devotion to morality is the only criterion for action, then the State, which is not an individual and which acts according to tradi tional rules and practices, is exposed to a fundamental criticism, and punishment, law, and property may then be recorded as purely incidental to the execution of political justice. Further, for Godwin it is not enough, in his search for justice, to ask whether a particular law, punishment, or property right, is just, but whether law, punish ment, and property are proper instruments for determining the relations between men in society. His posing of this latter question indicates that he presupposes a different set of criteria for ascertaining justice. Godwin’s political thought is widely dispersed throughout many of his writings, including essays and novels, but the most complete ex pression of his political philosophy is contained in the Enquiry Concern ing Political Justice and Its Influence on General Virtue and Happiness, referred to in the following pages as either the Enquiry or Political Justice, The first publication of Politica l .Jugtige appeared in 1795 but Godwin revised it twice, publishing the second edition in 1796 and the third in 179S. The text cited in this study is F. E. L. Priestley’s edition of 19^6. This is a photographic facsimile of the third edition, but it also records Godwin’s revisions in such a way that the passages of the first two editions can be reconstructed for comparison. For pur poses of this study, the writer accepts the opinion of F. E. L. Priestley that the changes made in the later editions are of relatively minor importance•
THE SUBJECT REALITY OF VIOLENT WOMEN
(1996-08) Erin Adams; York, Lorraine; English
The aim of this thesis is to examine the means by which the media present feminine violence in such a way as to re-enforce the patriarchal structures most threatened by violent women's assumptions of subjectivity. By publicly stereotyping violent women, the media consistently displace the meaning of feminine violence by continuing "to perceive and portray the act of murder by women as an unnatural and isolated event." Aggression in women is, with few exceptions, always spoken of either in relation to domestic abuse, or women's sexuality, or both. Stereotyping women who kill as doing so only within one or the other of these contexts corresponds neatly to the rigidly formulaic nineteenth-century categorization of women writers that Sandra M. Gilbert and Susan Gubar outline in their book, The Madwoman in the Atticz those of the "angel" and the "monster.

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