In-flight calibration of the high-gain antenna pointing for the Mariner Venus-Mercury 1973 spacecraft

The methods used to in-flight calibrate the pointing direction of the Mariner Venus-Mercury 1973 spacecraft high gain antenna and the achieved antenna pointing accuracy are described. The overall pointing calibration was accomplished by performing calibration sequences at a number of points along the spacecraft trajectory. Each of these consisted of articulating the antenna about the expected spacecraft-earth vector to determine systematic pointing errors. The high gain antenna pointing system, the error model used in the calibration, and the calibration and pointing strategy and results are discussed

Pedagogy Analysis Framework: a video-based tool for combining teacher, pupil & researcher perspectives

Background: dialogue between the teaching profession and researchers regarding pedagogical strategy is sometimes problematic. Pedagogy research may benefit from incorporating research methods that can investigate teachers’ and pupils’ interpretations. Purpose: this research expands the Pedagogy Analysis Framework (Riordan, 2020) by explaining in detail the meso-strategies (tactics) and a macro-strategy (grand strategy) used by participants in three school science lessons about chromatography. The research design builds on previous work by using full lessons and introducing pupil group verbal protocols. In addition, Pedagogy Analysis Notation is introduced to help understand and explain macro-strategic behaviours. Sample: one class of thirty 13-year-old pupils and one science teacher. Design and method: four research methods were used (lesson video analysis, teacher verbal protocols, pupil group verbal protocols and researcher group interviews). Data were video recorded (managed using NVivo). Fourteen hours of video data were analysed using Grounded Theory Methods by two educational researchers and the class teacher. The interpretivist theoretical perspective (symbolic interactionism) was underpinned by a social constructionist epistemology (hence the methodology is Straussian Grounded Theory). Appropriate criteria for evaluating the emergent grounded theory were used. Data were recorded in 2017. Results: the Pedagogy Analysis Framework uses the concepts: means (human and non-human), strategy (a spectrum from micro-strategies (actions), through meso-strategies (tactics) to macro-strategies (grand strategies)), ends (regarding the self, another person or a thing, or a group of people or things), and accidents. Types of tactics identified in these data were: inform (misinform and disinform), question, instruct, use space/time, repeat, train, assess, and interact. Pedagogy Analysis Notation is used to understand and explain ‘the stationary [sic] cupboard’ incident. Conclusion: the extended Pedagogy Analysis Framework, combined with the Pedagogy Analysis Notation, improves strategic dialogue between teachers, pupils and educational researchers. This research design facilitates comparison of interpretations of classroom pedagogy by a teacher, pupils and two researchers

A material-dialogic perspective on powerful knowledge and matter within a science classroom

“Powerful” disciplinary knowledge has the potential to enrich students’ lives by providing access to understanding beyond everyday experience (Young 2011). Learning science or any other school subject requires understanding of the core body of content within an academic discipline. However, contemporary discussion of disciplinary knowledge remains at the sociological level, offering little clarity around how such knowledge manifests in the complex and unique contexts in which people learn. The framing of powerful knowledge inherits a dualist philosophical assumption that a curriculum concept is a universal phenomenon, acquired through a myriad of activities and applied in new situations, but nevertheless something which is acquired (or not) (Hardman, 2019). The question then becomes how these universal concepts are acquired through the unique context of a specific classroom. Gericke et al. (2018) begin to address this question by highlighting the transformations made as disciplinary knowledge is taught in schools. These transformations occur at the societal, institutional and classroom levels. The term ‘transformation’ is an umbrella term reflected in both the tradition of didactics, for example, ‘didactic transposition’ (Chevallard 2007), ‘omstilling’ (Ongstad 2006) and ‘reconstruction’ (Duit 2013), as well as within the curriculum tradition in Bernstein’s (1973) notion of ‘re-contextualization’. As well as considering transformations, the term epistemic quality moves us towards conceptualizing how classroom activities have differing qualities in conveying the epistemology of disciplines (Hudson, 2018). In this chapter, we focus on the classroom, and seek to address the overarching question of: How can the transformation processes related to powerful knowledge and epistemic quality be described? Our contention is that the notions of transformation and epistemic quality hold the potential to frame the ways in which disciplinary knowledge and epistemology manifest in the classroom. However, as these notions are being developed, in this book and elsewhere, we wish to guard against any simplistic framing whereby idealised disciplinary understandings are in some way represented in classrooms. In our view, a learner does not receive a reduced, simplified form of some universal understanding. Understanding of a subject discipline, in terms of both knowledge and the epistemology of the discipline, emerge from the dynamic, messy and material contexts of classrooms. In this chapter, we consider how a material-dialogic frame (Hetherington et al. 2018; Hetherington and Wegerif, 2018) might contribute to this discussion. We first briefly lay out the material-dialogic frame and our reasons for proposing it. After that, we use a case study of a science classroom to support the usefulness of the frame in considering transformations of disciplinary knowledge in classrooms

Pedagogy Analysis Framework: a video-based tool for combining teacher, pupil & researcher perspectives

BACKGROUND: dialogue between the teaching profession and researchers regarding pedagogical strategy is sometimes problematic. Pedagogy research may benefit from incorporating research methods that can investigate teachers’ and pupils’ interpretations. PURPOSE: this research expands the Pedagogy Analysis Framework (Riordan, 2020) by explaining in detail the meso-strategies (tactics) and a macro-strategy (grand strategy) used by participants in three school science lessons about chromatography. The research design builds on previous work by using full lessons and introducing pupil group verbal protocols. In addition, Pedagogy Analysis Notation is introduced to help understand and explain macro-strategic behaviours. SAMPLE: one class of thirty 13-year-old pupils and one science teacher. DESIGN AND METHOD: four research methods were used (lesson video analysis, teacher verbal protocols, pupil group verbal protocols and researcher group interviews). Data were video recorded (managed using NVivo). Fourteen hours of video data were analysed using Grounded Theory Methods by two educational researchers and the class teacher. The interpretivist theoretical perspective (symbolic interactionism) was underpinned by a social constructionist epistemology (hence the methodology is Straussian Grounded Theory). Appropriate criteria for evaluating the emergent grounded theory were used. Data were recorded in 2017. RESULTS: the Pedagogy Analysis Framework uses the concepts: means (human and non-human), strategy (a spectrum from micro-strategies (actions), through meso-strategies (tactics) to macro-strategies (grand strategies)), ends (regarding the self, another person or a thing, or a group of people or things), and accidents. Types of tactics identified in these data were: inform (misinform and disinform), question, instruct, use space/time, repeat, train, assess, and interact. Pedagogy Analysis Notation is used to understand and explain ‘the stationary [sic] cupboard’ incident. CONCLUSION: the extended Pedagogy Analysis Framework, combined with the Pedagogy Analysis Notation, improves strategic dialogue between teachers, pupils and educational researchers. This research design facilitates comparison of interpretations of classroom pedagogy by a teacher, pupils and two researchers

Reactions of alcohols in acetic anhydride-mineral acid mixtures

The reaction of 3β-cholestanol with acetic anhydride and sulphuric acid has been studied. A kinetic investigation has been made of the reaction of these reagents with cyclohexanol, 1-methylcyclohexanol and a series of benzyl alcohols. The relative rates for the reaction of some 6β-substituted-3β-acetoxycholestan-5α-ols in this system have been determined and the rates compared with that for 1-methylcyclohexanol. The reaction of 3β,6β-diacetoxycholestan-5α-ol with fluosulphonic acid has been shown to involve a "backbone" rearrangement terminated at a position intermediate between those usually found. The structure of one of the products has been determined and a structure is suggested for another product

Quantum tunneling dynamics of an interacting Bose-Einstein condensate through a Gaussian barrier

The transmission of an interacting Bose-Einstein condensate incident on a repulsive Gaussian barrier is investigated through numerical simulation. The dynamics associated with interatomic interactions are studied across a broad parameter range not previously explored. Effective 1D Gross-Pitaevskii equation (GPE) simulations are compared to classical Boltzmann-Vlasov equation (BVE) simulations in order to isolate purely coherent matterwave effects. Quantum tunneling is then defined as the portion of the GPE transmission not described by the classical BVE. An exponential dependence of transmission on barrier height is observed in the purely classical simulation, suggesting that observing such exponential dependence is not a sufficient condition for quantum tunneling. Furthermore, the transmission is found to be predominately described by classical effects, although interatomic interactions are shown to modify the magnitude of the quantum tunneling. Interactions are also seen to affect the amount of classical transmission, producing transmission in regions where the non-interacting equivalent has none. This theoretical investigation clarifies the contribution quantum tunneling makes to overall transmission in many-particle interacting systems, potentially informing future tunneling experiments with ultracold atoms.Comment: Close to the published versio

The Increasing Role of Percutaneous Transluminal Angioplasty in the Primary Management of Critical Limb Ischaemia

AbstractObjective: to review the current role and results of angioplasty in the management of critical limb ischaemia (CLI) in a single institution.Methods: data on 526 patients with 608 ischaemic limbs, treated between January 1994 and December 1999 was collected prospectively and analysed retrospectively. Patients were divided into 3 groups according to the date of presentation: group 1 (1994–95), group 2 (1996–97) and group 3 (1998–99). The groups were comparable in terms of demographics, mode of presentation and level of disease.Results: Revascularisation was attempted in 87%, 81% and 91% for groups 1, 2 and 3 respectively (NS). Primary percutaneous transluminal angioplasty (PTA) rates increased from 44% (1994–95) to 69% (1998–99) (p < 0.001), and surgical revascularisation rates decreased correspondingly (p<0.01). Overall cumulative patient survival and limb salvage rates were 82% and 89% for 1 year and 45% and 87% for 5 years, respectively. No statistically significant difference existed between the three groups regarding patient survival, limb salvage rates and mean hospital stay (19, 12 and 12 days, respectively).Conclusion: PTA is increasingly replacing bypass surgery in the treatment of CLI, without compromising patient survival or limb salvage rates

Optically guided linear Mach Zehnder atom interferometer

We demonstrate a horizontal, linearly guided Mach Zehnder atom interferometer in an optical waveguide. Intended as a proof-of-principle experiment, the interferometer utilises a Bose-Einstein condensate in the magnetically insensitive |F=1,mF=0> state of Rubidium-87 as an acceleration sensitive test mass. We achieve a modest sensitivity to acceleration of da = 7x10^-4 m/s^2. Our fringe visibility is as high as 38% in this optically guided atom interferometer. We observe a time-of-flight in the waveguide of over half a second, demonstrating the utility of our optical guide for future sensors.Comment: 6 pages, 3 figures. Submitted to Phys. Rev.

Characterization of designed, synthetically accessible bryostatin analog HIV latency reversing agents.

HIV latency in resting CD4+ T cell represents a key barrier preventing cure of the infection with antiretroviral drugs alone. Latency reversing agents (LRAs) can activate HIV expression in latently infected cells, potentially leading to their elimination through virus-mediated cytopathic effects, host immune responses, and/or therapeutic strategies targeting cells actively expressing virus. We have recently described several structurally simplified analogs of the PKC modulator LRA bryostatin (termed bryologs) designed to improve synthetic accessibility, tolerability in vivo, and efficacy in inducing HIV latency reversal. Here we report the comparative performance of lead bryologs, including their effects in reducing cell surface expression of HIV entry receptors, inducing proinflammatory cytokines, inhibiting short-term HIV replication, and synergizing with histone deacetylase inhibitors to reverse HIV latency. These data provide unique insights into structure-function relationships between A- and B-ring bryolog modifications and activities in primary cells, and suggest that bryologs represent promising leads for preclinical advancement