Revival of the magnetar PSR J1622-4950: observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR

New radio (MeerKAT and Parkes) and X-ray (XMM-Newton, Swift, Chandra, and NuSTAR) observations of PSR J1622-4950 indicate that the magnetar, in a quiescent state since at least early 2015, reactivated between 2017 March 19 and April 5. The radio flux density, while variable, is approximately 100x larger than during its dormant state. The X-ray flux one month after reactivation was at least 800x larger than during quiescence, and has been decaying exponentially on a 111+/-19 day timescale. This high-flux state, together with a radio-derived rotational ephemeris, enabled for the first time the detection of X-ray pulsations for this magnetar. At 5%, the 0.3-6 keV pulsed fraction is comparable to the smallest observed for magnetars. The overall pulsar geometry inferred from polarized radio emission appears to be broadly consistent with that determined 6-8 years earlier. However, rotating vector model fits suggest that we are now seeing radio emission from a different location in the magnetosphere than previously. This indicates a novel way in which radio emission from magnetars can differ from that of ordinary pulsars. The torque on the neutron star is varying rapidly and unsteadily, as is common for magnetars following outburst, having changed by a factor of 7 within six months of reactivation.Comment: Published in ApJ (2018 April 5); 13 pages, 4 figure

Advancing a holistic systems approach for sustainable cattle development programmes in South Africa: insights from sustainability assessments

Efforts to exploit the central roles of cattle to drive agriculture and rural development in low-income countries recorded limited success owing to their narrow focus on modernizing and commercializing low-input cattle farming. Most programs failed to take cognizance of the heterogeneous range of complex relationships between the environmental, economic, social and institutional challenges that limit low-input cattle farming. The current qualitative literature review evaluates the environmental, economic and social sustainability delivery impacts of the leading cattle development programs in the low-input farming sector in South Africa using a holistic systems approach. A mixed method procedure involving stratified sampling was used to allocate local and international-based programs while, purposive sampling was used to select programs with a wider scale of operation. The review then draws on the crosscutting key constraints emerging from the case studies to provide a better grounding for subsequent sustainability sensitive recommendations. Local-based cattle development programs advanced more market-led interventions while, their international-based counterparts had more interventions including, soil and rangeland improvement. The narrow focus by both local and international developmental programs is inadequate to address a wide array of environmental, economic, social, technical and institutional challenges faced by low-input cattle producers in South Africa.The Department of Science and Technology-National Research Foundation (DST-NRF) Centre of Excellence (CoE) in Food Security [140102].https://www.tandfonline.com/loi/wjsa212021-01-23hj2020Gordon Institute of Business Science (GIBS

Pro et Contra of Agriculture Land Reform in South Africa: A Policy Brief

The simulation results presented in this paper provided nuanced policy options for redistribution in South Africa in the face of the looming expropriation of land without compensation. The simulation done through Computable General Equilibrium approach using the modified University of Pretoria General Equilibrium Model (UPGEM) which is solved using a GEMPACK solution software. The simulation revealed that there will be adjustment costs regardless of the option(s) chosen. The Inclusive Scenario came up as the most suitable policy option in terms of minimal adjustment costs and allowing the sector to continue to grow, albeit at a lower rate compared to the status quo

Pro et Contra of Agriculture Land Reform in South Africa: A Policy Brief

The simulation results presented in this paper provided nuanced policy options for redistribution in South Africa in the face of the looming expropriation of land without compensation. The simulation done through Computable General Equilibrium approach using the modified University of Pretoria General Equilibrium Model (UPGEM) which is solved using a GEMPACK solution software. The simulation revealed that there will be adjustment costs regardless of the option(s) chosen. The Inclusive Scenario came up as the most suitable policy option in terms of minimal adjustment costs and allowing the sector to continue to grow, albeit at a lower rate compared to the status quo