Our understanding of the tectonic development of the African continent and the interplay between its geological provinces is hindered by unevenly distributed seismic instrumentation. In order to ...better understand the continent, we used long‐period ambient noise full‐waveform tomography on data collected from 186 broadband seismic stations throughout Africa and surrounding regions to better image the upper mantle structure. We extracted empirical Green's functions from ambient seismic noise using a frequency‐time normalization method and retrieved coherent signal at periods of 7–340 s. We simulated wave propagation through a heterogeneous Earth using a spherical finite‐difference approach to obtain synthetic waveforms, measured the misfit as phase delay between the data and synthetics, calculated numerical sensitivity kernels using the scattering integral approach, and iteratively inverted for structure. The resulting images of isotropic, shear wave speed for the continent reveal segmented, low‐velocity upper mantle beneath the highly magmatic northern and eastern sections of the East African Rift System (EARS). In the southern and western sections, high‐velocity upper mantle dominates, and distinct, low‐velocity anomalies are restricted to regions of current volcanism. At deeper depths, the southern and western EARS transition to low velocities. In addition to the EARS, several low‐velocity anomalies are scattered through the shallow upper mantle beneath Angola and North Africa, and some of these low‐velocity anomalies may be connected to a deeper feature. Distinct upper mantle high‐velocity anomalies are imaged throughout the continent and suggest multiple cratonic roots within the Congo region and possible cratonic roots within the Sahara Metacraton.
Plain Language Summary
We use advanced seismic imaging techniques (full‐waveform tomography), constrained by data from background (ambient) seismic noise to image the upper mantle beneath the African continent and search for low‐velocity structures (hot spots) that might coincide with regions of volcanism, surface uplift, and continental rifting, particularly along the East African Rift. We also searched for high‐velocity structures (old, rigid blocks) that could influence how warm, buoyant material flows within the Earth's upper mantle. Our seismic tomography method allowed us to obtain a clear image of structure beneath parts of Africa where no or very few seismometers are located (such as the Sahara Desert and the Congo Basin). Our results provide indications for segmented secondary (or shallow) upwellings in the upper mantle beneath East Africa, as opposed to earlier models suggesting one large, continuous plume within the upper mantle. Our results also suggest that the one large, rigid, cratonic block previously imaged beneath the Congo region may instead be composed of smaller, distinct blocks. These results provide insight into the factors that control continental rifting along East Africa and provide new testable models that help us to understand the relationships between upper mantle flow, rifting, volcanism, surface uplift, and sedimentation records.
Key Points
Full‐waveform, long‐period ambient noise tomography was used to produce a new isotropic Vs model of the upper mantle beneath Africa
Several cratonic fragments have been imaged in the upper mantle, particularly within the Congo Craton
Results suggest multiple upwellings beneath Africa, including complex patterns of low‐velocity features beneath the East African Rift System
The Coronavirus Disease 2019 (COVID-19) has impacted overall nursing education program requirements, classroom delivery of theory hours, as well as clinical and laboratory learning opportunities for ...students. The aims of this study were to explore the impacts of COVID 19 on the students' perceptions of readiness for practice and their preparation for the NCLEX exam and initial clinical practice.
A cross-sectional descriptive design was used to investigate the impact of COVID-19 on senior BSN students' preparation for NCLEX and future careers. The Casey-Fink Readiness for Practice Survey was used to investigate the perceptions of the BSN students' clinical confidence and readiness for practice.
Students reported substantial impacts of COVID-19 on their clinical experiences, their ability to practice skills and procedures, their preparations for NCLEX exam, and their nursing career. The most significant confidence concerns noted from this study seemed to center on handling multiple patient assignments, calling the physician, responding to a change in patient condition, and treating a dying patient.
Healthcare experts expect that the impact of COVID-19 may last until 2022. More research is needed to understand the impact of COVID-19 on nursing education and transition to nursing practice. While clinical confidence and readiness for practice are essential topics, more research is needed to investigate the psychological and physiological impacts of COVID-19 on nurses, nursing students, nursing preceptors, and faculty members.
The Psychosocial Theoretical Model of Gifted Adolescent Girls' Career Development (PTM) is a framework which reveals the interrelated factors that influence career development for gifted adolescent ...girls. The model was developed during the completion of a PhD thesis (Napier, 2020) and provides important new insights to support their career trajectories and encourage further research. The PTM is a comprehensive and compact guide for gifted education stakeholders in their advisory, support, and decision-making roles for this population. In particular, it facilitates both population and more bespoke career development provisions for gifted adolescent girls who, research indicates (Napier, 2020), are often motivated to meaningfully transform our world for the better. A range of significant recommendations is also provided for families, schools, and communities to support these young people who are altruistically driven to use their strengths and interests to make a difference in others' lives.
Courageous and innovative individuals are needed urgently to work on the wicked problems and challenges of our modern world. This paper explores a critical solutions source, namely the education of ...transformationally gifted adolescent girls who "seek positively to change the world at some level -- to make the world a better place" (Sternberg, 2020, p. 30). Altruism is the central drive of transformational giftedness. Recent research indicates that gifted adolescent girls have the dispositions, expertise, and abiding sense of hope-"fullness" needed to harness their core altruistic career-related values and high abilities to significantly impact the common good (Napier, 2020). Napier and Sternberg argue that transformational giftedness should be identified and nurtured in educational environments to benefit gifted adolescent girls' self-actualisation and society at large. Recommendations are made for educational policy and practice to identify and nurture transformationally oriented gifted adolescent girls' career trajectories.
During the 2018 eruption of Kīlauea Volcano, Hawai'i, scientists relied heavily on a conceptual model of explosive eruptions triggered when lava-lake levels drop below the water table. Numerical ...modeling of multiphase groundwater flow and heat transport revealed that, contrary to expectations, liquid water inflow to the drained magma conduit would likely be delayed by months to years, owing to the inability of liquid water to transit a zone of very hot rock. The summit of Kīlauea subsequently experienced an ∼2-month period of consistent repeated collapses, and the crater now extends below the equilibrium position of the water table. Liquid water first emerged into the deepened crater in late July 2019. The timing of first appearance of liquid water (about 14 months postcollapse) and the rate of crater lake filling (currently ∼27 kg/s) were well-predicted by the numerical modeling done in late spring 2018, which forecast liquid inflow after 3 to 24 months at rates of 10 to 100 kg/s. A second-generation groundwater model, reflecting the current crater geometry, forecasts lake filling over the next several years. The successful 2018 to present forecasts with both models are based on unadjusted in situ permeability estimates (1 to 6 × 10
m
) and water-table elevations (600 to 800 m) from a nearby research drillhole and geophysical surveys. Important unknowns that affect the reliability of longer-term forecasts include the equilibrium water-table geometry, the rate of evaporation from the hot and growing crater lake (currently ∼29,000 m
at 70-80 °C), and heterogenous permeability changes caused by the 2018 collapse.
This study investigates the relationship between early childhood (EC) and early years' primary school (EYPS) teachers' phonological awareness (PA) assessment practices, self-reported PA knowledge and ...actual PA knowledge. A survey design was employed whereby 102 registered Australian EC and EYPS teachers responded to questions regarding PA assessment practices, self-reported PA knowledge and actual PA knowledge. The results showed: a) more than 80% of teachers use PA assessments, with EYPS teachers conducting frequent assessments and EC teachers conducting rare-to-occasional assessments; b) overestimation of self-reported PA knowledge; c) low levels of actual PA knowledge; and d) high usage of observations and professional judgement as assessment methods despite limited own PA knowledge. Increasing EC and EYPS teachers' knowledge of PA and improving their self-appraisal skills is critical for high-quality teacher PA assessment practices, and it illustrates the need for robust pre- and in-service teacher training. Author abstract
The Australian Curriculum (ACARA, 2016, v.8.2) acknowledges that gifted and talented students are diverse and require educational provisions that meet their special needs. However, without ...professional learning in gifted education, teachers are ill-equipped to understand, identify and provide for gifted students. This article reviews the literature in the field to argue for consideration of a 'gifted dimension' as an elaboration of the Australian Professional Standards for Teachers (AITSL, 2011). As all teachers will teach gifted and talented children, it is important to define the elements of quality teaching that are inclusive of high ability students in the Australian context and contribute to a professional learning agenda for all teachers. Author abstract
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