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BEB-based models for ionisation cross sections of electron and positron impact with diatomic molecules
The ionising interactions of high-energy particles with molecules have applications in many areas. Despite this, some areas, including positron scattering, lack experimental data due to difficulties in performing experiments. Here, quick and simple methods for computing direct electron and positron impact ionisation cross sections are presented. These calculations, performed using the open-source software RAPID-CS, can provide a complete data set as a first approximation for when experimental, or more detailed computational work is not available. The cross-sectional data set includes the total, partial/fragment-specific, single-differential, average secondary electron energy and stopping power cross sections. The molecules N2, O2 and CO were chosen to study due to the availability of positron scattering data. An overall good agreement with experimental and other computational results is presented.
Graphical abstract
Direct electron (left) and positron right) impact partial ionisation cross sections for N2. Total cross section: red, N2+ partial cross section: blue, N+ partial cross section: green.electron: solid lines: BEB, experimental measurements by Lindsay and Mangan :Ürosses, Straub et al. : stars, Opel et al. : squares. Positron: solid lines: BEB0, Dashed lines: BEBA, Marler and Surko : red crosses, Bluhme et al. : star
Supporting students’ basic psychological needs and satisfaction in a blended learning environment through learning analytics
In designing a blended learning environment (BLE), a key challenge is to ensure students have a motivating and satisfactory learning experience in both online and face-to-face components. This study addresses this challenge by investigating the impact of using learning analytics (LA) to support students' autonomy and competence needs within a BLE context. Specifically, it examines the effect of teachers sharing LA reports with students on their basic psychological needs and satisfaction in a blended university-based teacher education course. The quasi-experimental study employed a mixed-method approach and spanned two months (N = 348). In the experimental condition, teachers provide specific LA information to students and adjust face-to-face instruction accordingly, while the control group does not receive these adaptations. The findings show that students are generally satisfied with the adapted learning environment, recognizing the value of teachers' LA-based adaptations. Results regarding students' basic psychological needs vary depending on the face-to-face workshop subject. This study contributes to the existing literature by highlighting how teachers' LA-based adaptations positively influence students' satisfaction with the learning environment, fulfilling their psychological needs. It underscores the significance of thoughtful BLE course design and provides recommendations for effective LA utilization in university settings. Based on the findings, several recommendations emerge. Data collection should prioritize group-level anonymity to ensure privacy. Digital learning platforms should provide clear and concise data visualizations to facilitate effective communication between teachers and students. Teachers should leverage LA insights to adapt face-to-face activities in the BLE. Clear guidance should be available to support teachers in utilizing LA effectively
Lithosphere tearing and foundering during continental subduction: insights from Oligocene-Miocene magmatism in southern Tibet
The distribution of Oligo-Miocene magmatic rocks from southern Tibet in space and time yields critical information on the geometry and deformation of the subducted Indian lithosphere which impacts on plateau growth following the India and Eurasia collision. A growing body of geophysical evidence has shown that the subducted Indian lithosphere beneath the Tibetan Plateau has been torn apart. However, the spatiotemporal distribution and cause of the tearing remain enigmatic. Timing of the post-collisional magmatic rocks in southern Tibet exhibits four patterns of decreasing ages; magmatism began earlier in the west and east Himalayan syntaxis and evolved to two age undulations in the central southern Tibet. Seismic images show that regions of slab window (90°E and 84°E) and flattened subducted lithosphere (86°E and 81°E) are present at depth of 135 km. Correspondingly, increasing mineral crystallization temperatures (absolute value of ±50 ℃) were recorded in the Oligo-Miocene ultrapotassic-potassic rocks from 90°E and 84°E, while opposing trends were shown by coeval ultrapotassic-potassic rocks from 86°E and 81°E. Besides, the melting depth of the Oligo-Miocene ultrapotassic-potassic primitive melts decreases from nearly 100 km to 70 km between 81°E and 90°E, probably indicating progressive rising of the lithosphere-asthenosphere boundary. Such variations were possibly the results of the focused flow and upwelling of asthenosphere, which advanced rapidly but diachronously through weakened and torn sectors within the overlying Indian slab. The upwellings probably induced diachronously upward bending of the residual Indian slab and its flattening, which accelerated the tearing of the Indian lithosphere during continental subduction
Realistic Ambitions: Technology Transfer for Biologics Platform Technologies
This chapter argues that the recent international support for expanding vaccine production in African countries offers local policymakers and industrialists an opportunity that should be seized, to transition local manufacturing capabilities to produce biologics. Biologics offer a broader portfolio of cancer therapies. Biologics such as monoclonal antibodies represent an incremental innovation for vaccine manufacturers, with lower learning and transition costs than those that would be faced by manufacturers of chemical drugs seeking to move into biologics. However, biologics production in Africa is not only a technological project, it is also political and economic, feeding into geo-politics debates
Promoting workplace retention during global crises: An international survey of the preventive role of psychological support among victims of social discrimination in long-term care facilities
This international cross-sectional survey examined the potential role of organizational psychological support in mitigating the association between experiencing social discrimination against long-term care (LTC) facilities’ healthcare professionals (HCPs) and their intention to stay in the current workplace during the COVID-19 pandemic. Participants included a convenience sample of 2,143 HCPs (nurses [21.5 %], nurse aids or residential care workers [40.1 %], social workers [12.1 %], and others [26.4 %]) working at 223 LTC facilities in 13 countries/regions. About 37.5 % of the participants reported experiencing social discrimination, and the percentage ranged from 15.3 % to 77.9 % across countries/regions. Controlling for socio-demographic and work-related variables, experiencing social discrimination was significantly associated with a lower intention to stay, whereas receiving psychological support showed a statistically significant positive association (p-value=0.015 and <0.001, respectively). The interaction term between social discrimination and psychological support showed a statistically significant positive association with the intention to stay, indicating a moderating role of the psychological support
Absolute dimensions of solar-type eclipsing binaries: NY Hya: A test for magnetic stellar evolution models
Context. The binary star NY Hya is a bright, detached, double-lined eclipsing system with an orbital period of just under five days with two components each nearly identical to the Sun and located in the solar neighbourhood.
Aims. The objective of this study is to test and confront various stellar evolution models for solar-type stars based on accurate measurements of stellar mass and radius.
Methods. We present new ground-based spectroscopic and photometric as well as high-precision space-based photometric and astrometric data from which we derive orbital as well as physical properties of the components via the method of least-squares minimisation based on a standard binary model valid for two detached components. Classic statistical techniques were invoked to test the significance of model parameters. Additional empirical evidence was compiled from the public domain; the derived system properties were compared with archival broad-band photometry data enabling a measurement of the system’s spectral energy distribution that allowed an independent estimate of stellar properties. We also utilised semi-empirical calibration methods to derive atmospheric properties from Strömgren photometry and related colour indices.
Results. We measured (percentages are fractional uncertainties) masses, radii, and effective temperatures of the two stars in NY Hya and found them to be MA = 1.1605 ± 0.0090 M⊙ (0.78%), RA = 1.407 ± 0.015 R⊙ (1.1%), Teff, A = 5595 ± 61 K (1.09%), MB = 1.1678 ± 0.0096 M⊙ (0.82%), RB = 1.406 ± 0.017 R⊙ (1.2%), and Teff, B = 5607 ± 61 K (1.09%). The atmospheric properties from Strömgren photometry agree well with spectroscopic results. No evidence was found for nearby companions from high-resolution imaging. A detailed analysis of space-based data revealed a small but significant eccentricity (e cos ω) of the orbit. The spectroscopic and frequency analysis on photometric time series data reveal evidence of clear photospheric activity on both components likely in the form of star spots caused by magnetic activity.
Conclusions. We confronted the observed physical properties with classic and magnetic stellar evolution models. Classic models yielded both young pre-main-sequence and old main-sequence turn-off solutions with the two components at super-solar metallicities, in disagreement with observations. Based on chromospheric activity and X-ray observations, we invoke magnetic models. While magnetic fields are likely to play an important role, we still encounter problems in explaining adequately the observed properties. To reconcile the observed tensions we also considered the effects of star spots known to mimic magnetic inhibition of convection. Encouraging results were obtained, although unrealistically large spots were required on each component. Overall we conclude that NY Hya proves to be complex in nature, and requires additional follow-up work aiming at a more accurate determination of stellar effective temperature and metallicity
Online group projects in higher education: persistent challenges and implications for practice
With the rapid adoption of online learning across higher education, there is an urgent need to identify its challenges and ways of addressing them. Online group projects, in particular, present significant issues for educators. This paper presents the findings of a systematic literature review identifying the key challenges of online group projects, together with strategies to address them. From a corpus of 114 recent papers, the 57 most relevant were analysed, to identify themes related to challenges and strategies. Key challenges were: low and uneven participation by students; a lack of clarity and preparation for students; and poor relationships. Strategies for addressing challenges were: careful design of projects, particularly regarding fair assessment; clear guidance and preparation of students; and practical and emotional support throughout, to encourage confidence and engagement. The findings of this review will enable educators to design and facilitate online group projects which students find rewarding and valuable
Periodic Bedrock Ridges at Oxia Planum and Chryse Planitia, Mars: Evidence for widespread aeolian erosion of an ancient surface by regional paleowinds
Periodic Bedrock Ridges (PBRs) are repeating, symmetrical, wind-transverse, bedrock-abraded linear ridges that occur on Mars as parallel sets. Here, we extend our previous survey of PBRs at Oxia Planum – the landing site of ESA's ExoMars Rosalind Franklin rover – to include three additional sites along the margins of the circum-Chryse basin to understand patterns in PBR orientation and occurrence. We analyzed PBR crestline orientation at each study site and found them to be consistent across this large region, but their orientations do not align with global circulation model winds, suggesting contemporary winds are not responsible for PBR development. Furthermore, we used observations of landscape-level stratigraphic relationships at Oxia Planum to constrain the formation age of PBRs to be late Noachian to early Amazonian. Their consistent orientations and age suggest that the Chryse-margin PBRs formed concurrently and represent modification of an ancient palaeosurface. In addition, we find a tendency for PBRs to preferentially occur in regions where Fe/Mg-rich phyllosilicate minerals were detected in hyperspectral remote sensing data. We conclude that regional scale aeolian processes formed the circum-Chryse PBRs, and that exposed bedrock with Fe/Mg-rich phyllosilicate detections were either more susceptible to PBR formation, or better preserve PBRs than other regional lithologies
Is there H<sub>2</sub>O stacking disordered ice I in the Solar System?
Water ice exists in large quantities across the Solar System, and it is involved in a wide range of atmospheric and geological processes. Here we focus on the question if stacking disordered ice I (ice Isd) is present in the Solar System. The conditions required to form ice Isd are described and we argue that previous descriptions of ‘cubic ice’ (ice Ic) in the literature may in fact have been concerned with ice Isd. In contrast to the stable hexagonal ice I (ice Ih) and ice Ic, ice Isd is a highly complex material that encompasses a wide range of possible stacking regimes and structures. The most fundamental quantity to describe a given ice Isd sample is its cubicity which reflects the fraction of cubic stacking. Following an introduction into the characterisation techniques used to identify and characterise ice Isd, we discuss the various environments in the Solar System where ice Isd may exist and the relevance its existence may have. This includes the atmospheres of the inner planets, various icy moons as well as comets and other icy objects in the far reaches of the Solar System. The details of the stacking disorder may contain information about the formation and thermal history of ice Isd samples. This offers the exciting prospect of using ice Isd as a marker material for atmospheric and geological processes. The crystallographic space group of ice Isd allows polar structures which could be an important factor for the accretion of ice particles in space. We conclude that ice Isd should exist at several locations in the Solar System and in potentially large quantities. The definitive identification of ice Isd in a natural environment is a next major milestone in our understanding of the importance of water ice across the Solar System