University of Johannesburg

About: University of Johannesburg is a education organization based out in Johannesburg, South Africa. It is known for research contribution in the topics: Population & Context (language use). The organization has 8070 authors who have published 22749 publications receiving 329408 citations. The organization is also known as: UJ.

Measurements of W ± Z production cross sections in pp collisions at √s = 8 TeV with the ATLAS detector and limits on anomalous gauge boson self-couplings

Abstract: This paper presents measurements of W(+/-)Z production in pp collisions at a center-of-mass energy of 8 TeV. The gauge bosons are reconstructed using their leptonic decay modes into electrons and m ...

Iridaceae ‘Out of Australasia’? Phylogeny, Biogeography, and Divergence Time Based on Plastid DNA Sequences

Abstract: The current infrafamilial taxonomy of the Iridaceae recognizes four subfamilies; Isophysidoideae (1: 1); Nivenioideae (6: ca. 92), Iridoideae (29: 890), and Crocoideae (29: 1032). Phylogenetic analyses of sequences of five plastid DNA regions, rbcL, rps4, trnL–F, matK, and rps16, confirm most aspects of this classification and the evolutionary patterns that they imply, importantly the sisiter relationship of Isophysidoideae to the remainder of the family and the monophyly of Iridoideae. Subfamily Nivenioideae is, however, paraphyletic; Crocoideae is consistently found nested within it, sister to the core Nivenioideae, the woody Klattia, Nivenia, and Witsenia. This clade is sister to Aristea, which in turn is sister to the Madagascan Geosiris, and then to the Australasian Patersonia. We treat Aristea, Geosiris, and Patersonia as separate subfamilies, Aristeoideae and the new Geosiridaceae and Patersonioideae, rendering Nivenioideae and Crocoideae monophyletic. The alternative, uniting a widely cir...

Spiny plants, mammal browsers, and the origin of African savannas.

Abstract: Savannas first began to spread across Africa during the Miocene. A major hypothesis for explaining this vegetation change is the increase in C4 grasses, promoting fire. We investigated whether mammals could also have contributed to savanna expansion by using spinescence as a marker of mammal herbivory. Looking at the present distribution of 1,852 tree species, we established that spinescence is mainly associated with two functional types of mammals: large browsers and medium-sized mixed feeders. Using a dated phylogeny for the same tree species, we found that spinescence evolved at least 55 times. The diversification of spiny plants occurred long after the evolution of Afrotherian proboscideans and hyracoids. However, it is remarkably congruent with diversification of bovids, the lineage including the antelope that predominantly browse these plants today. Our findings suggest that herbivore-adapted savannas evolved several million years before fire-maintained savannas and probably, in different environmental conditions. Spiny savannas with abundant mammal herbivores occur in drier climates and on nutrient-rich soils, whereas fire-maintained savannas occur in wetter climates on nutrient-poor soils.

Global value chains and the rise of the Global South: unpacking twenty‐first century polycentric trade

Abstract: A growing body of research points to the ‘Rise of the South’ and the growth of South–South trade. In this article, we consider the implications of the shifting dynamics of global trade and the greater prominence of Southern actors for the conceptualization of global value chains (GVCs) and global production networks (GPNs). We use trade data analysis to explore the changing geography of global trade and to highlight the emergence of more polycentric trade. We argue that our understanding of GVCs and GPNs, in a context where Southern actors and Southern end markets have more prominent roles, requires greater attention to the existence of multiple value chains (VCs) and production networks (PNs) serving different end markets – including domestic, regional and global. Consequently, there is a need to refine our understanding of both governance dynamics – lead firm strategies and standards requirements – and upgrading prospects through recognizing this shifting trade geography. We conclude by raising several new research questions regarding the conceptualization of VCs and PNs in a world where Southern actors and Southern markets are increasingly important.

Work Engagement, Burnout and Related Constructs as Predictors of Turnover Intentions

Abstract: Orientation: The focus of the study was to investigate the predictive relationship between the work engagement-burnout continuum and turnover intentions. Research purpose: The main purpose of the study was to determine whether work engagement, burnout, organisational citizenship behaviour (OCB) and work alienation are predictors of turnover intentions. Motivation for the study: Organisations operating within the 21st century face significant challenges in the management of talent and human capital. One in particular is voluntary employee turnover and the lack of appropriate business models to track this process. Research design, approach and method: A secondary data analysis (SDA) was performed in a quantitative research tradition on the cross-sectional survey data collected from a large South African Information and Communication Technologies (ICT) sector company ( n = 2429). Main findings: The results of the study confirmed the predictive model (work engagement, burnout, OCB and work alienation) of turnover intention. Specifically, work engagement and OCBs were significantly negatively related to turnover intention; whilst burnout and work alienation were significantly positively related to turnover intention. Several third-variable relationships, such as biographic and demographic variables, indicated statistical significance. Practical/managerial implications: Practical implications of the study could impact on human resource (HR) value-chain activities in the form of evidence-based and improved recruitment and selection procedures, employee retention strategies and training and development interventions. Issues concerning talent management could also be addressed. Contribution/value-add: The study described in this article took Industrial/Organisational (I/O) psychological concepts and linked them in unique combinations to establish better predictive validity of a new turnover intentions model.