Tests of Nacelle-Propeller Combinations in Various Positions with Reference to Wings VI : Wings and Nacelles with Pusher Propeller

This report is the sixth of a series giving wind tunnel tests results on the interference drag and propulsive efficiency of nacelle-propeller-wing combinations. The present report gives the results of tests of a radial-engine nacelle with pusher propeller in 17 positions with reference to a Clark Y wing; tests of the same nacelle and propeller in three positions with reference to a thick wing; and tests of a body and pusher propeller with the thick wing, simulating the case of a propeller driven by an extension shaft from an engine within the wing. Some preliminary tests were made on pusher nacelles alone

Using the Theory of Practice Architectures to establish what it means to “do” learning design, and the arrangements that enable and constrain practice

In the past decade, learning design has become a widely adopted field of practice for higher education institutions (HEI) engaged with producing online and distance learning materials. To date, much has been written about the conceptual principles of guidance, representation, and sharing that underpin learning design, and the theoretical frameworks, models, tools, and instruments that have also been developed to support it. However, little analysis has been done to describe learning design in the specific sites of practice into which it has been introduced, or to describe the arrangements that might enable or constrain the embedding of this digital learning innovation by the people tasked with doing so. This original research article utilizes the Theory of Practice Architectures (TPA) as a theoretical approach to establish what learning design practice is composed of, and how that practice is shaped by its multiple sites of practice in the STEM faculty of a large open and distance learning HEI. The analysis draws on evidence—captured longitudinally over 4 years—from surveys (n = 43), learning design analytics (n = 20), in-depth interviews with key stakeholders (n = 14), document analysis, and learning design workshop data (n = 28) about the journey of 28 modules from conceptualization to faculty approval for full module production. The application of TPA to this extensive data set offers new and under discussed identification of key challenges experienced in the adoption of learning design approaches. In the sites of practice explored here, two specific arrangements are discussed: time, and the legacy of the Open University Learning Design Initiative (OULDI). Both can be seen to constrain and enable practice in different ways. This study will be relevant for scholars and researchers attempting to evaluate current learning design approaches or looking to explore more accurate ways of describing what it means to “do” learning design, both now and in the future

Are We Living in LA (P)LA Land? Reporting on the Practice of 30 STEM Tutors in Their Use of a Learning Analytics Implementation at The Open University

Most higher education institutions view their increasing use of learning analytics as having significant potential to improve student academic achievement, retention outcomes, and learning and teaching practice but the realization of this potential remains stubbornly elusive. While there is an abundance of published research on the creation of visualizations, dashboards, and predictive models, there has been little work done to explore the impact of learning analytics on the actual practice of teachers. Through the lens of social informatics (an approach that views the users of technologies as active social actors whose technological practices constitute a wider socio-technical system) this qualitative study reports on an investigation into the practice of 30 tutors in the STEM faculty at Europe’s largest distance learning organization, The Open University UK (OU). When asked to incorporate learning analytics (including predictive learning analytics) contained in the Early Alert Indicator (EAI) dashboard during the 2017–2018 academic year into their practice, we found that tutors interacted with this dashboard in certain unanticipated ways and developed three identifiable “shadow practices”

Online remote exams in higher education: distance learning students' views

As a result of the Covid-19 pandemic, universities had to re-structure their assessment design, policies and processes. It is clear that the experiment of having exams delivered in an online format has allowed institutions to question what the most appropriate format for the future is (St-Onge et al., 2022). The assessment conversation around the design of the online exams and the technology used aimed at ensuring that student expectations were met while securing assessment standards. This study aimed to explore student views at a major distance-learning university in the UK about participating in online remote exams. The institution replaced the common pre-covid practice of taking face-to-face exams at local centres appointed by the university with remote open book-style exams. This work focuses on responses to: (a) a closed-ended question on whether students had a positive, negative or mixed experience with online exams and (b) an open-ended exploratory question inviting students to report their previous experiences with online exams, if any. Content analysis was used to make valid inferences from the survey respondents’ open-ended responses focusing on the meaning in context (Krippendorff, 2018). The majority of respondents (83%) reported that they never completed an online remote exam at home (or work) as an alternative to their face-to-face exams. The rest (n = 107) completed online remote exams at home in one course (12%) or more than one course (5%). This may have occurred due to pandemic or to accommodate students with disabilities or other circumstances as part of standard processes. The students who completed an exam at home mainly described their experience as positive (76%, n = 81). However, some students had a mixed (19%, n = 20) or negative (5%, n = 5) experience. Findings from 107 student responses to an online survey on assessment, pointed to positive and negative areas of experience with online exams. Exploring students’ comments on positive experiences (n = 76), the area with the largest proportion of positive mentions (36%) was ‘exam duration and time’, followed by ‘anxiety/pressure’ (26%), ‘exams at home’ (20%), ‘travel to exam centre’ (16%), ‘real-life equivalent’ (8%), and ‘invigilation’(4%). Exploring students’ comments on negative experiences (n = 15), the area with the largest proportion of negative mentions (52%) was ‘equipment and technical issues’, followed by ‘invigilation and rigorousness’ (26%), ‘exam duration and time’ (9%), ‘marks’ (8%), and ‘distractions at home’ (7%). The evidence from this study suggests that while most survey respondents show a clear preference towards online remote exams, there is no clear ‘winner’ as different groups of students reveal barriers and challenges in assuming a different exam model. This study provides an agenda for universities with temporary and permanent distance learning programmes to develop or improve ways that students or particular groups of students are assessed by providing positive areas of perception. References: [1] Krippendorff, K. (2018). Content analysis: An introduction to its methodology. Sage publications. [2] St‐Onge, C., Ouellet, K., Lakhal, S., Dubé, T., & Marceau, M. (2022). COVID‐19 as the tipping point for integrating e‐assessment in higher education practices. British Journal of Educational Technology, 53(2), 349-366

Examining university student satisfaction and barriers to taking online remote exams

Recent years have seen a surge in the popularity of online exams at universities, due to the greater convenience and flexibility they offer both students and institutions. Driven by the dearth of empirical data on distance learning students' satisfaction levels and the difficulties they face when taking online exams, a survey with 562 students at The Open University (UK) was conducted to gain insights into their experiences with this type of exam. Satisfaction was reported with the environment and exams, while work commitments and technical difficulties presented the greatest barriers. Gender, race and disability were also associated with different levels of satisfaction and barriers. This study adds to the increasing number of studies into online exams, demonstrating how this type of exam can still have a substantial effect on students experienced in online learning systems and technologies

Online exams in higher education: Exploring distance learning students' acceptance and satisfaction

Background Research into online exams in higher education has grown significantly, especially as they became common practice during the COVID-19 pandemic. However, previous studies focused on understanding individual factors that relate to students' dispositions towards online exams in ‘traditional’ universities. Moreover, there is little knowledge on university distance learning students' experience of transitioning from in-person to online exams. Objectives This study investigates the acceptance and satisfaction of university distance learning students in their transitioning from in-person to online exams, through multiple factors. Methods We employed a mixed-methods study to understand the relationship between assessment and online exam factors (e.g., revision and online exam satisfaction, assessment competencies, invigilation acceptance, exam anxiety and workspace satisfaction). Cluster analysis and interview data contributed to our understanding of students who are ‘strongly positive’ and ‘less positive’ towards online exams. Results and Conclusions Our findings highlight the overall importance of increasing student confidence by building their assessment competencies throughout their studies and familiarising them early with the technologies and formats to be used in the actual exam. We also shed light on particular student characteristics that relate to reduced online exam acceptance, such as students with disabilities, caring responsibilities and mental health issues, or students who lack access to the necessary technology. Implications The findings and recommendations of this research contribute to the wider agenda of designing fair and trustworthy online assessment, including exams, for the futur

White Dwarfs in Globular Clusters: HST Observations of M4

Using WFPC2 on the Hubble Space Telescope, we have isolated a sample of 258 white dwarfs (WDs) in the Galactic globular cluster M4. Fields at three radial distances from the cluster center were observed and sizeable WD populations were found in all three. The location of these WDs in the color-magnitude diagram, their mean mass of 0.51($\pm 0.03$)M$_{\odot}$, and their luminosity function confirm basic tenets of stellar evolution theory and support the results from current WD cooling theory. The WDs are used to extend the cluster main-sequence mass function upward to stars that have already completed their nuclear evolution. The WD/red dwarf binary frequency in M4 is investigated and found to be at most a few percent of all the main-sequence stars. The most ancient WDs found are about 9 Gyr old, a level which is set solely by the photometric limits of our data. Even though this is less than the age of M4, we discuss how these cooling WDs can eventually be used to check the turnoff ages of globular clusters and hence constrain the age of the Universe.Comment: 46 pages, latex, no figures included, figures available at ftp://ftp.astro.ubc.ca/pub/richer/wdfig.uu size 2.7Mb. To be published in the Astrophysical Journa

Effect of combined uphill-downhill sprint training on kinematics and maximum running speed in experienced sprinters

This study examined the effects of sprint running training on sloping surfaces (3°) in experienced sprinters using selected kinematic variables. Twelve experienced sprinters were randomly allocated to two training groups (combined uphill–downhill and horizontal). Pre- and post-training tests were performed to examine the effects of six weeks of training on maximum running speed, step rate, step length, step time, contact time, braking and propulsive phase of contact time, flight time and selected postural characteristics during a step cycle in the final steps of a 35m sprint test. In the combined uphill–downhill training group, maximum running speed was substantially greater (from 9.08 ± 0.90 m s-1 to 9.51 ± 0.62 m s-1; p <0.05) after training by 4.8%; step rate, contact time, step time and concentric phase was not modified. There were no significant changes in maximal speed or sprint kinematics in the horizontal training group. Overall, the posture characteristics did not change with training. The combined uphill–downhill training method was substantially more effective in improving the maximum running speed in experienced sprinters than a traditional horizontal training method

EVLA Observations Constrain the Environment and Progenitor System of Type Ia Supernova 2011fe

We report unique EVLA observations of SN 2011fe representing the most sensitive radio study of a Type Ia supernova to date. Our data place direct constraints on the density of the surrounding medium at radii ~10^15-10^16 cm, implying an upper limit on the mass loss rate from the progenitor system of Mdot <~ 6 x 10^-10 Msol/yr (assuming a wind speed of 100 km/s), or expansion into a uniform medium with density n_CSM <~ 6 cm^-3. Drawing from the observed properties of non-conservative mass transfer among accreting white dwarfs, we use these limits on the density of the immediate environs to exclude a phase space of possible progenitors systems for SN 2011fe. We rule out a symbiotic progenitor system and also a system characterized by high accretion rate onto the white dwarf that is expected to give rise to optically-thick accretion winds. Assuming that a small fraction, 1%, of the mass accreted is lost from the progenitor system, we also eliminate much of the potential progenitor parameter space for white dwarfs hosting recurrent novae or undergoing stable nuclear burning. Therefore, we rule out the most popular single degenerate progenitor models for SN 2011fe, leaving a limited phase space inhabited by some double degenerate systems and exotic progenitor scenarios.Comment: Accepted to Ap

Viral CpG Deficiency Provides No Evidence That Dogs Were Intermediate Hosts for SARS-CoV-2.

Due to the scope and impact of the COVID-19 pandemic there exists a strong desire to understand where the SARS-CoV-2 virus came from and how it jumped species boundaries to humans. Molecular evolutionary analyses can trace viral origins by establishing relatedness and divergence times of viruses and identifying past selective pressures. However, we must uphold rigorous standards of inference and interpretation on this topic because of the ramifications of being wrong. Here, we dispute the conclusions of Xia (2020. Extreme genomic CpG deficiency in SARS-CoV-2 and evasion of host antiviral defense. Mol Biol Evol. doi:10.1093/molbev/masa095) that dogs are a likely intermediate host of a SARS-CoV-2 ancestor. We highlight major flaws in Xia's inference process and his analysis of CpG deficiencies, and conclude that there is no direct evidence for the role of dogs as intermediate hosts. Bats and pangolins currently have the greatest support as ancestral hosts of SARS-CoV-2, with the strong caveat that sampling of wildlife species for coronaviruses has been limited