University of Stirling

About: University of Stirling is a education organization based out in Stirling, Stirling, United Kingdom. It is known for research contribution in the topics: Population & Context (language use). The organization has 7722 authors who have published 20549 publications receiving 732940 citations. The organization is also known as: Stirling University.

Systemic insecticides (neonicotinoids and fipronil): trends, uses, mode of action and metabolites

Abstract: Since their discovery in the late 1980s, neonicotinoid pesticides have become the most widely used class of insecticides worldwide, with large-scale applications ranging from plant protection (crops, vegetables, fruits), veterinary products, and biocides to invertebrate pest control in fish farming. In this review, we address the phenyl-pyrazole fipronil together with neonicotinoids because of similarities in their toxicity, physicochemical profiles, and presence in the environment. Neonicotinoids and fipronil currently account for approximately one third of the world insecticide market; the annual world production of the archetype neonicotinoid, imidacloprid, was estimated to be ca. 20,000 tonnes active substance in 2010. There were several reasons for the initial success of neonicotinoids and fipronil: (1) there was no known pesticide resistance in target pests, mainly because of their recent development, (2) their physicochemical properties included many advantages over previous generations of insecticides (i.e., organophosphates, carbamates, pyrethroids, etc.), and (3) they shared an assumed reduced operator and consumer risk. Due to their systemic nature, they are taken up by the roots or leaves and translocated to all parts of the plant, which, in turn, makes them effectively toxic to herbivorous insects. The toxicity persists for a variable period of time—depending on the plant, its growth stage, and the amount of pesticide applied. A wide variety of applications are available, including the most common prophylactic non-Good Agricultural Practices (GAP) application by seed coating. As a result of their extensive use and physicochemical properties, these substances can be found in all environmental compartments including soil, water, and air. Neonicotinoids and fipronil operate by disrupting neural transmission in the central nervous system of invertebrates. Neonicotinoids mimic the action of neurotransmitters, while fipronil inhibits neuronal receptors. In doing so, they continuously stimulate neurons leading ultimately to death of target invertebrates. Like virtually all insecticides, they can also have lethal and sublethal impacts on non-target organisms, including insect predators and vertebrates. Furthermore, a range of synergistic effects with other stressors have been documented. Here, we review extensively their metabolic pathways, showing how they form both compound-specific and common metabolites which can themselves be toxic. These may result in prolonged toxicity. Considering their wide commercial expansion, mode of action, the systemic properties in plants, persistence and environmental fate, coupled with limited information about the toxicity profiles of these compounds and their metabolites, neonicotinoids and fipronil may entail significant risks to the environment. A global evaluation of the potential collateral effects of their use is therefore timely. The present paper and subsequent chapters in this review of the global literature explore these risks and show a growing body of evidence that persistent, low concentrations of these insecticides pose serious risks of undesirable environmental impacts.

Discourse and Identity

Abstract: 'Identity' is a central organizing feature of our social world. Across the social sciences and humanities, it is increasingly treated as something that is actively and publicly accomplished in discourse. This book defines identity in its broadest sense, in terms of how people display who they are to each other. Each chapter examines a different discursive environment in which people do 'identity work': everyday conversation, institutional settings, narrative and stories, commodified contexts, spatial locations, and virtual environments. The authors describe and demonstrate a range of discourse and interaction analytic methods as they are put to use in the study of identity, including 'performative' analyses, conversation analysis, membership categorization analysis, critical discourse analysis, narrative analysis, positioning theory, discursive psychology and politeness theory. The book aims to give readers a clear sense of the coherence (or otherwise) of these different approaches, the practical steps taken in analysis, and their situation within broader critical debates. Through the use of detailed and original 'identity' case studies in a variety of spoken and written texts in order, the book offers a practical and accessible insight into what the discursive accomplishment of identity actually looks like, and how to go about analyzing it. Features:*Accessible introduction to the study of discourse and identity across a variety of contexts.*Interdisciplinary in scope, the book is relevant to a wide range of courses such as English language and linguistics, psychology, media, cultural studies, gender studies and sociology.*Each chapter includes a critical overview of work in the area, original case studies, practical instruction for analyses, points for further discussion and suggested reading.

Good education in an age of measurement: on the need to reconnect with the question of purpose in education

Abstract: In this paper I argue that there is a need to reconnect with the question of purpose in education, particularly in the light of a recent tendency to focus discussions about education almost exclusively on the measurement and comparison of educational outcomes. I first discuss why the question of purpose should always have a place in our educational discussion. I then explore some reasons why this question seems to have disappeared from the educational agenda. The central part of the paper is a proposal for addressing the question of purpose in education—the question as to what constitutes good education—in a systematic manner. I argue that the question of purpose is a composite question and that in deliberating about the purpose of education we should make a distinction between three functions of education to which I refer as qualification, socialisation and subjectification. In the final section of the paper I provide examples of how this proposal can help in asking more precise questions about the purpose and direction of educational processes and practices.

Neonicotinoid Pesticide Reduces Bumble Bee Colony Growth and Queen Production

Abstract: Growing evidence for declines in bee populations has caused great concern because of the valuable ecosystem services they provide. Neonicotinoid insecticides have been implicated in these declines because they occur at trace levels in the nectar and pollen of crop plants. We exposed colonies of the bumble bee Bombus terrestris in the laboratory to field-realistic levels of the neonicotinoid imidacloprid, then allowed them to develop naturally under field conditions. Treated colonies had a significantly reduced growth rate and suffered an 85% reduction in production of new queens compared with control colonies. Given the scale of use of neonicotinoids, we suggest that they may be having a considerable negative impact on wild bumble bee populations across the developed world.