Showing papers by "Open University published in 2021"

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)

Abstract: In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field.

Phosphine gas in the cloud decks of Venus

Abstract: Measurements of trace gases in planetary atmospheres help us explore chemical conditions different to those on Earth. Our nearest neighbour, Venus, has cloud decks that are temperate but hyperacidic. Here we report the apparent presence of phosphine (PH3) gas in Venus’s atmosphere, where any phosphorus should be in oxidized forms. Single-line millimetre-waveband spectral detections (quality up to ~15σ) from the JCMT and ALMA telescopes have no other plausible identification. Atmospheric PH3 at ~20 ppb abundance is inferred. The presence of PH3 is unexplained after exhaustive study of steady-state chemistry and photochemical pathways, with no currently known abiotic production routes in Venus’s atmosphere, clouds, surface and subsurface, or from lightning, volcanic or meteoritic delivery. PH3 could originate from unknown photochemistry or geochemistry, or, by analogy with biological production of PH3 on Earth, from the presence of life. Other PH3 spectral features should be sought, while in situ cloud and surface sampling could examine sources of this gas. The detection of ~20 ppb of phosphine in Venus clouds by observations in the millimetre-wavelength range from JCMT and ALMA is puzzling, because according to our knowledge of Venus, no phosphine should be there. As the most plausible formation paths do not work, the source could be unknown chemical processes—maybe even life?

Why 'the uplift of the Tibetan Plateau' is a myth.

Abstract: The often-used phrase ‘the uplift of the Tibetan Plateau’ implies a flat-surfaced Tibet rose as a coherent entity, and that uplift was driven entirely by the collision and northward movement of India. Here, we argue that these are misconceptions derived in large part from simplistic geodynamic and climate modeling, as well as proxy misinterpretation. The growth of Tibet was a complex process involving mostly Mesozoic collisions of several Gondwanan terranes with Asia, thickening the crust and generating complex relief before the arrival of India. In this review, Earth system modeling, paleoaltimetry proxies and fossil finds contribute to a new synthetic view of the topographic evolution of Tibet. A notable feature overlooked in previous models of plateau formation was the persistence through much of the Cenozoic of a wide east–west orientated deep central valley, and the formation of a plateau occurred only in the late Neogene through compression and internal sedimentation.

The TESS Objects of Interest Catalog from the TESS Prime Mission

Abstract: We present 2241 exoplanet candidates identified with data from the Transiting Exoplanet Survey Satellite (TESS) during its 2 yr Prime Mission. We list these candidates in the TESS Objects of Interest (TOI) Catalog, which includes both new planet candidates found by TESS and previously known planets recovered by TESS observations. We describe the process used to identify TOIs, investigate the characteristics of the new planet candidates, and discuss some notable TESS planet discoveries. The TOI catalog includes an unprecedented number of small planet candidates around nearby bright stars, which are well suited for detailed follow-up observations. The TESS data products for the Prime Mission (sectors 1-26), including the TOI catalog, light curves, full-frame images, and target pixel files, are publicly available at the Mikulski Archive for Space Telescopes.

Low‐carbon transition risks for finance

Abstract: The transition to a low‐carbon economy will entail a large‐scale structural change. Some industries will have to expand their relative economic weight, while other industries, especially those directly linked to fossil fuel production and consumption, will have to decline. Such a systemic shift may have major repercussions on the stability of financial systems, via abrupt asset revaluations, defaults on debt, and the creation of bubbles in rising industries. Studies on previous industrial transitions have shed light on the financial transition risks originating from rapidly rising “sunrise” industries. In contrast, a similar conceptual understanding of risks from declining “sunset” industries is currently lacking. We substantiate this claim with a critical review of the conceptual and historical literature, which also shows that most literature either examines structural change in the real economy, or risks to financial stability, but rarely both together. We contribute to filling this research gap by developing a consistent theoretical framework of the drivers, transmission channels, and impacts of the phase‐out of carbon‐intensive industries on the financial system and on the feedback from the financial system into the rest of the economy. We also review the state of play of policy aiming to protect the financial system from transition risks and spell out research implications.

Mixed-Methods Research: A Discussion on its Types, Challenges, and Criticisms

Abstract: The article positions mixed-method research (MMR) as a principled complementary research method to the traditional quantitative and qualitative research approaches. By situating MMR in an analysis of some of the common research paradigms, the article presents it as a natural choice in order to complement and cater to the increasingly complex needs of contemporary researchers. It proffers MMR as a flexible and adaptive conceptual framework for designing and conducting mixed methods research in a simplified manner. By explaining fundamental principles and major theoretical tenets of a mixed-methods approach, which involves both quantitative and qualitative data collection in response to research questions, it elucidates several benefits of adopting MMR since it integrates post-positivism as well as interpretivism frameworks. There is abundant literature around this research design aiming to provide researchers an understanding of the approach. Yet there is limited literature that provides illustrative guidance to research novices in comprehending mixed methods, understanding reasons for choosing it, and selecting an appropriate mixed methods design. Based on an analysis of some notable works in the field, this article provides an overview of mixed methods designs, discusses its main types, and explains challenges one can potentially encounter when in using them with a view to assisting early career researchers in particular and other researchers in general.

Tin oxide for optoelectronic, photovoltaic and energy storage devices: a review

Abstract: Tin dioxide (SnO2), the most stable oxide of tin, is a metal oxide semiconductor that finds its use in a number of applications due to its interesting energy band gap that is easily tunable by doping with foreign elements or by nanostructured design such as thin film, nanowire or nanoparticle formation, etc., and its excellent thermal, mechanical and chemical stability. In particular, its earth abundance and non-toxicity make it very attractive for use in a number of technologies for sustainable development such as energy harvesting and storage. This article attempts to review the state of the art of synthesis and properties of SnO2, focusing primarily on its application as a transparent conductive oxide (TCO) in various optoelectronic devices and second in energy harvesting and energy storage devices where it finds its use as an electron transport layer (ETL) and an electrode material, respectively. In doing so, we discuss how tin oxide meets the requirements for the above applications, the challenges associated with these applications, and how its performance can be further improved by adopting various strategies such as doping with foreign metals, functionalization with plasma, etc. The article begins with a review on the various experimental approaches to doping of SnO2 with foreign elements for its enhanced performance as a TCO as well as related computational studies. Herein, we also compare the TCO performance of doped tin oxide as a function of dopants such as fluorine (F), antimony (Sb), tantalum (Ta), tungsten (W), molybdenum (Mo), phosphorus (P), and gallium (Ga). We also discuss the properties of multilayer SnO2/metal/SnO2 structures with respect to TCO performance. Next, we review the status of tin oxide as a TCO and an ETL in devices such as organic light emitting diodes (OLEDs), organic photovoltaics (OPV), and perovskite solar cells (including plasma treatment approaches) followed by its use in building integrated photovoltaic (BIPV) applications. Next, we review the impact of SnO2, mainly as an electrode material on energy storage devices starting from the most popular lithium (Li)-ion batteries to Li–sulfur batteries and finally to the rapidly emerging technology of supercapacitors. Finally, we also compare the performance of doped SnO2 with gallium (Ga) doped zinc oxide (ZnO), the main sustainable alternative to SnO2 as a TCO and summarize the impact of SnO2 on circular economies and discuss the main conclusions and future perspectives. It is expected that the review will serve as an authoritative reference for researchers and policy makers interested in finding out how SnO2 can contribute to the circular economy of some of the most desired sustainable and clean energy technologies including the detailed experimental methods of synthesis and strategies for performance enhancement.

A novel version of Cuckoo search algorithm for solving optimization problems

Abstract: In this paper, a Cuckoo search algorithm, namely the New Movement Strategy of Cuckoo Search (NMS-CS), is proposed. The novelty is in a random walk with step lengths calculated by Levy distribution. The step lengths in the original Cuckoo search (CS) are significant terms in simulating the Cuckoo bird's movement and are registered as a scalar vector. In NMS-CS, step lengths are modified from the scalar vector to the scalar number called orientation parameter. This parameter is controlled by using a function established from the random selection of one of three proposed novel functions. These functions have diverse characteristics such as; convex, concave, and linear, to establish a new strategy movement of Cuckoo birds in NMS-CS. As a result, the movement of NMS-CS is more flexible than a random walk in the original CS. By using the proposed functions, NMS-CS achieves the distance of movement long enough at the first iterations and short enough at the last iterations. It leads to the proposed algorithm achieving a better convergence rate and accuracy level in comparison with CS. The first 23 classical benchmark functions are selected to illustrate the convergence rate and level of accuracy of NMS-CS in detail compared with the original CS. Then, the other Algorithms such as Particle Swarm Optimization (PSO), Gravitational Search Algorithm (GSA), and Grey Wolf Optimizer (GWO) are employed to compare with NMS-CS in a ranking of the best accuracy. In the end, three engineering design problems (tension/compression spring design, pressure vessel design and welded beam design) are employed to demonstrate the effect of NMS-CS for solving various real-world problems. The statistical results show the potential performance of NMS-CS in a widespread class of optimization problems and its excellent application for optimization problems having many constraints. Source codes of NMS-CS is publicly available at http://goldensolutionrs.com/codes.html .

Oxia Planum: The Landing Site for the ExoMars "rosalind Franklin" Rover Mission: Geological Context and Prelanding Interpretation

Abstract: The European Space Agency (ESA) and Roscosmos ExoMars mission will launch the “Rosalind Franklin” rover in 2022 for a landing on Mars in 2023.The goals of the mission are to search for signs of pas...

Participatory Research Approaches in Times of Covid-19: A Narrative Literature Review

Abstract: This review aims to collate and organize the current literature base on the use of participatory research methods within Covid-19 and pandemic contexts. Participatory approaches rely on establishin...

A dry lunar mantle reservoir for young mare basalts of Chang'e-5.

Abstract: The distribution of water in the Moon’s interior carries implications for the origin of the Moon1, the crystallisation of the lunar magma ocean2, and the duration of lunar volcanism2. The Chang’E-5 (CE5) mission returned the youngest mare basalt samples, dated at 2.0 billion years ago (Ga)3, from the northwestern Procellarum KREEP Terrane (PKT), providing a probe into the spatiotemporal evolution of lunar water. Here we report the water abundances and hydrogen isotope compositions of apatite and ilmenite-hosted melt inclusions from CE5 basalts. We derive a maximum water abundance of 283 ± 22 μg.g-1 and a δD value of -330 ± 190‰ for the parent magma. Accounting for a low degree partial melting of the depleted mantle followed by extensive magma fractional crystallisation4, we estimate a maximum mantle water abundance of 1-5 μg.g-1, suggesting that the Moon’s youngest volcanism was not driven by abundant water in its mantle source. Such modest water contents for the CE5 basalt mantle source region is at the low end of the range estimated from mare basalts that erupted from ca. 4.0-2.8 Ga5,6, suggesting that the mantle source of CE5 basalts had become dehydrated by 2.0 Ga through previous melt extraction from the PKT mantle during prolonged volcanic activity.

IT architecture flexibility and IT governance decentralisation as drivers of IT-enabled dynamic capabilities and competitive performance: The moderating effect of the external environment

Abstract: A question of central importance for researchers and practitioners is how information technology (IT) can help firms survive and thrive in turbulent and constantly changing business environments. T...

Analysis of Teachers’ Pedagogical Digital Competence: Identification of Factors Predicting Their Acquisition

Abstract: The current technological revolution has reached all social classes and its educative use by teachers has not gone unnoticed. The introduction of 2.0 tools has become a reality in many classrooms. In order to evaluate the digital competence of teachers, different dimensions must be considered, including knowledge and educative use. The first objective of this research is to find out whether there are any differences between the knowledge and use of teaching staff of ICT, specifically regarding different 2.0 tools, as well as different modules on the Moodle virtual platform, using the t-Student test. The second objective is to analyse, through a multiple linear regression model, which factors have an effect on the level of digital competence: gender, age and educational stage. With this aim, a non-experimental, ex post facto type of research has been carried out with a study population of 81 teachers from the community of Madrid (Spain). The results have shown that there are statistically significant differences between the knowledge and use of 2.0 tools and Moodle Modules. In addition, the results have found that the variables age and gender have an effect on the prediction of the level of pedagogical digital competence of the teaching staff, while the educational stage in which they teach has no effect. The conclusions derived from this study can help to develop educational interventions focused on improving the unfavourable digital competence of teachers.

Financial Inclusion and Economic GROWTH: An International Evidence

Abstract: Policies on financial inclusion have attracted great attention from scholars, policymakers, and regulators, as financial inclusion has theoretically been acknowledged to have positive effect on eco...

Detection of tuberculosis from chest X-ray images: Boosting the performance with vision transformer and transfer learning

Abstract: Tuberculosis (TB) caused by Mycobacterium tuberculosis is a contagious disease which is among the top deadly diseases in the world. Research in Medical Imaging has been done to provide doctors with techniques and tools to early detect, monitor and diagnose the disease using Artificial Intelligence. Recently, many attempts have been made to automatically recognize TB from chest X-ray (CXR) images. Still, while the obtained performance is encouraging, according to our investigation, many of the existing approaches have been evaluated on small and undiverse datasets. We suppose that such a good performance might not hold for heterogeneous data sources, which originate from real world scenarios. Our present work aims to fill the gap and improve the prediction performance on larger datasets. In particular, we present a practical solution for the detection of tuberculosis from CXR images, making use of cutting-edge Machine Learning and Computer Vision algorithms. We conceptualize a framework by adopting three recent deep neural networks as the main classification engines, namely modified EfficientNet, modified original Vision Transformer, and modified Hybrid EfficientNet with Vision Transformer. Moreover, we also empower the learning process with various augmentation techniques. We evaluated the proposed approach using a large dataset which has been curated by merging various public datasets. The resulting dataset has been split into training, validation, and testing sets which account for 80%, 10%, and 10% of the original dataset, respectively. To further study our proposed approach, we compared it with two state-of-the-art systems. The obtained results are encouraging: the maximum accuracy of 97.72% with AUC of 100% is achieved with ViT_Base_EfficientNet_B1_224. The experimental results demonstrate that our conceived tool outperforms the considered baselines with respect to different quality metrics.

The Past, Present, and Future of Smart Tourism Destinations: A Bibliometric Analysis:

Abstract: Despite the emergence of the notion of smart tourism destinations in tourism research, few studies have delved deeply into the topic, and the little research focusing on the subject has not offered...

Optimizing multi-mode time-cost-quality trade-off of construction project using opposition multiple objective difference evolution

Abstract: The time, cost and quality are crucial, conflicting aspects to construction project management. Tradeoff optimization among project duration (time), project cost, and the project quality within the...

The LOFAR LBA Sky Survey I. Survey description and preliminary data release

Abstract: Context. The LOw Frequency ARray (LOFAR) is the only radio telescope that is presently capable of high-sensitivity, high-resolution (i.e. < 1 mJy beam −1 and < 15″) observations at ultra-low frequencies (< 100 MHz). To utilise these capabilities, the LOFAR Surveys Key Science Project is undertaking a large survey to cover the entire northern sky with Low Band Antenna (LBA) observations. Aims. The LOFAR LBA Sky Survey (LoLSS) aims to cover the entire northern sky with 3170 pointings in the frequency range between 42 − 66 MHz, at a resolution of 15″ and at a sensitivity of 1 mJy beam −1 (1 σ ). In this work, we outline the survey strategy, the observational status, and the calibration techniques. We also briefly describe several of our scientific motivations and present the preliminary public data release. Methods. The preliminary images were produced using a fully automated pipeline aimed at correcting all direction-independent effects in the data. Whilst the direction-dependent effects, such as those from the ionosphere, have not yet been corrected, the images presented in this work are still ten times more sensitive than previous available surveys at these low frequencies. Results. The preliminary data release covers 740 deg 2 around the HETDEX spring field region at an angular resolution of 47″ with a median noise level of 5 mJy beam −1 . The images and the catalogue of 25 247 sources have been publicly released. We demonstrate that the system is capable of reaching a root mean square (rms) noise of 1 mJy beam −1 and an angular resolution of 15″ once direction-dependent effects are accounted for. Conclusions. LoLSS will provide the ultra-low-frequency information for hundreds of thousands of radio sources, providing critical spectral information and producing a unique data set that can be used for a wide range of science topics, such as the search for high redshift galaxies and quasars, the study of the magnetosphere of exoplanets, and the detection of the oldest populations of cosmic-rays in galaxies, clusters of galaxies, as well as those produced by active galactic nuclei.

The LOFAR Two-meter Sky Survey: Deep Fields Data Release 1 - III. Host-galaxy identifications and value added catalogues

Abstract: We present the source associations, cross-identifications, and multi-wavelength properties of the faint radio source population detected in the deep tier of the LOFAR Two Metre Sky Survey (LoTSS): the LoTSS Deep Fields. The first LoTSS Deep Fields data release consists of deep radio imaging at 150~MHz of the ELAIS-N1, Lockman Hole, and Bo\"{o}tes fields, down to RMS sensitives of around 20, 22, and 32$~\mu$Jy\,beam$^{-1}$, respectively. These fields are some of the best studied extra-galactic fields in the northern sky, with existing deep, wide-area panchromatic photometry from X-ray to infrared wavelengths, covering a total of $\approx$~26~\mbox{deg$^{2}$}. We first generated improved multi-wavelength catalogues in ELAIS-N1 and Lockman Hole; combined with the existing catalogue for Bo\"{o}tes, we present forced, matched aperture photometry for over 7.2 million sources across the three fields. We identified multi-wavelength counterparts to the radio detected sources, using a combination of the Likelihood Ratio method and visual classification, which greatly enhances the scientific potential of radio surveys and allows for the characterisation of the photometric redshifts and the physical properties of the host galaxies. The final radio-optical cross-matched catalogue consists of 81\,951 radio-detected sources, with counterparts identified and multi-wavelength properties presented for 79\,820 ($>$97\%) sources. We also examine the properties of the host galaxies, and through stacking analysis find that the radio population with no identified counterpart is likely dominated by AGN at $z\sim3-4$. This dataset contains one of the largest samples of radio-selected star-forming galaxies and active galactic nuclei (AGN) at these depths, making it ideal for studying the history of star-formation, and the evolution of galaxies and AGN across cosmic time.