Turbulent Pumping of Magnetic Flux Reduces Solar Cycle Memory and thus Impacts Predictability of the Sun's Activity

Prediction of the Sun's magnetic activity is important because of its effect on space environment and climate. However, recent efforts to predict the amplitude of the solar cycle have resulted in diverging forecasts with no consensus. Yeates et al. (2008) have shown that the dynamical memory of the solar dynamo mechanism governs predictability and this memory is different for advection- and diffusion-dominated solar convection zones. By utilizing stochastically forced, kinematic dynamo simulations, we demonstrate that the inclusion of downward turbulent pumping of magnetic flux reduces the memory of both advection- and diffusion-dominated solar dynamos to only one cycle; stronger pumping degrades this memory further. Thus, our results reconcile the diverging dynamo-model-based forecasts for the amplitude of solar cycle 24. We conclude that reliable predictions for the maximum of solar activity can be made only at the preceding minimum--allowing about 5 years of advance planning for space weather. For more accurate predictions, sequential data assimilation would be necessary in forecasting models to account for the Sun's short memory.Comment: 4 figures, 1 tabl

Observations on the President’s Fiscal Year 2000 Federal Science and Technology Budget

http://deepblue.lib.umich.edu/bitstream/2027.42/89086/1/2000_FST_Budget_Analysis.pd

Observations on the President’s Fiscal Year 1999 Federal Science and Technology Budget

http://deepblue.lib.umich.edu/bitstream/2027.42/89085/1/1999_FST_Budget_Analysis.pd

Observations on the President’s Fiscal Year 2001 Federal Science and Technology Budget

http://deepblue.lib.umich.edu/bitstream/2027.42/89089/1/2001_FST_Budget_Analysis.pd

Launch of the Consensus Study Report on: The Root Causes of Low Vaccination Coverage and Under-Immunisation in Sub-Saharan Africa

MP4 Video; Size: 424MB; Duration: 1:30Please cite as: Academy of Science of South Africa (ASSAf), (2021). Launch of the Consensus Study Report on: The Root Causes of Low Vaccination Coverage and Under-Immunisation in Sub-Saharan Africa. [Online] Available at: http://hdl.handle.net/20.500.11911/205Despite the global availability of proven efficacious and cost-effective vaccines for the past several decades, vaccine-preventable diseases kill more than half a million children under five years of age every year In Africa –representing approximately 56% of global deaths (WHO, 2017). Sub–Saharan Africa (SSA) alone accounts for 40% of all global deaths, a phenomenon attributed to lack of access to available lifesaving vaccines (Wiysonge, Uthman, Ndumbe, & Hussey, 2012). WHO estimates that in 2019 the African region accounted for approximately 43% of unimmunised and incomplete immunised infants in the world (i.e.: 8.5 million of the global 19.4 million). Relatedly, the region scores the lowest immunisation coverage, at 76% versus the global coverage of 86% (WHO, 2020a). This is despite several documented efforts by different stakeholders to improve coverage in the region (Mihigo, Okeibunor, Anya, Mkanda, & Zawaira, 2017). Many studies have been conducted on coverage and drivers for and bottlenecks against immunisation in SSA. (Wiysonge, Uthman, Ndumbe, & Hussey, 2012), (Wiysonge, Young, Kredo, McCaul, & Volmik, 2015), (Mihigo, Okeibunor, Anya, Mkanda, & Zawaira, 2017), (Madhi & Rees, 2018) (Bangura, et al., 2020), all of which have observed that there is varied performance among the constituent countries, and also within countries over time, denoting some implicitly common underlying correlates threading through areas of higher performance; and the same is seen with the poorer performing areas. This consensus study therefore seeks to categorise and make explicit these “root causes” and based on documented successes, to make recommendations to address the bottlenecks and harness the opportunities for reaching every child with all the recommended vaccines. The theory of change presentation style used in this report, categorising the root causes under four broad interlinked themes, can provide a common basis to rally like-minded partners around a thematic cause and thus develop multicomponent, comprehensive strategies to bring about impactful change. This is in line with the call made by the World Health Organisation Strategic Advisory Group of Experts on Immunisation, which recommended that countries, regions and global immunisation partners commit to a comprehensive review of progress, impact, and implementation of the WHO Global Vaccine Action Plan to inform a post2020 strategy taking into account lessons learned. This strategy will assist with attaining the relevant United Nations Sustainable Development Goals by 2030.Department of Science and Innovation (DSI)(South Africa); South African Medical Research Council (SAMRC)(South Africa

Mission Concept for the Single Aperture Far-Infrared (SAFIR) Observatory

The Single Aperture Far-InfraRed (SAFIR) Observatory's science goals are driven by the fact that the earliest stages of almost all phenomena in the universe are shrouded in absorption by and emission from cool dust and gas that emits strongly in the far-infrared and submillimeter. Over the past several years, there has been an increasing recognition of the critical importance of this spectral region to addressing fundamental astrophysical problems, ranging from cosmological questions to understanding how our own Solar System came into being. The development of large, far-infrared telescopes in space has become more feasible with the combination of developments for the James Webb Space Telescope and of enabling breakthroughs in detector technology. We have developed a preliminary but comprehensive mission concept for SAFIR, as a 10 m-class far-infrared and submillimeter observatory that would begin development later in this decade to meet the needs outlined above. Its operating temperature (<4K) and instrument complement would be optimized to reach the natural sky confusion limit in the far-infrared with diffraction-limited peformance down to at least 40 microns. This would provide a point source sensitivity improvement of several orders of magnitude over that of Spitzer or Herschel, with finer angular resolution, enabling imaging and spectroscopic studies of individual galaxies in the early universe. We have considered many aspects of the SAFIR mission, including the telescope technology, detector needs and technologies, cooling method and required technology developments, attitude and pointing, power systems, launch vehicle, and mission operations. The most challenging requirements for this mission are operating temperature and aperture size of the telescope, and the development of detector arrays.Comment: 36 page