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 & Tourism. The organization has 8070 authors who have published 22749 publications receiving 329408 citations. The organization is also known as: UJ.

Use of Structural Equation Modeling in Tourism Research Past, Present, and Future

Abstract: This study reviewed use of covariance-based structural equation modeling (SEM) in 209 articles published in nine tourism journals between 2000 and 2011. Time-series analysis suggested that the number of SEM publications is explained by linear and quadratic time effects. Results indicated that although SEM practices have improved in some areas, tourism researchers do not always engage in the recommended best practices. Problematic areas were related to testing of alternative a priori models, reporting of multivariate normality, estimating effect size, and assessing reliability and validity. Some of the recommended fit indices were also underutilized. The review also found few differences in SEM practices between top-tier journals and other publications in the tourism field. On the basis of these results, suggestions to improve use of SEM in tourism studies are discussed in the light of recent developments in this technique.

Parasite responses to pollution: what we know and where we go in ‘Environmental Parasitology’

Abstract: Environmental parasitology deals with the interactions between parasites and pollutants in the environment. Their sensitivity to pollutants and environmental disturbances makes many parasite taxa useful indicators of environmental health and anthropogenic impact. Over the last 20 years, three main research directions have been shown to be highly promising and relevant, namely parasites as accumulation indicators for selected pollutants, parasites as effect indicators, and the role of parasites interacting with established bioindicators. The current paper focuses on the potential use of parasites as indicators of environmental pollution and the interactions with their hosts. By reviewing some of the most recent findings in the field of environmental parasitology, we summarize the current state of the art and try to identify promising ideas for future research directions. In detail, we address the suitability of parasites as accumulation indicators and their possible application to demonstrate biological availability of pollutants; the role of parasites as pollutant sinks; the interaction between parasites and biomarkers focusing on combined effects of parasitism and pollution on the health of their hosts; and the use of parasites as indicators of contaminants and ecosystem health. Therefore, this review highlights the application of parasites as indicators at different biological scales, from the organismal to the ecosystem.

Search for high-mass diboson resonances with boson-tagged jets in proton-proton collisions at √s=8 TeV with the ATLAS detector

Abstract: A search is performed for narrow resonances decaying into WW, WZ, or ZZ boson pairs using 20.3 fb(-1) of proton-proton collision data at a centre-of-mass energy of root s = TeV recorded with the AT ...

Search for dark matter in events with a hadronically decaying W or Z boson and missing transverse momentum in pp collisions at √s = 8 TeV with the ATLAS detector

Abstract: A search is presented for dark matter pair production in association with a W or Z boson in pp collisions representing 20.3 fb(-1) of integrated luminosity at root s = 8 TeV using data recorded with the ATLAS detector at the Large Hadron Collider. Events with a hadronic jet with the jet mass consistent with a W or Z boson, and with large missing transverse momentum are analyzed. The data are consistent with the standard model expectations. Limits are set on the mass scale in effective field theories that describe the interaction of dark matter and standard model particles, and on the cross section of Higgs production and decay to invisible particles. In addition, cross section limits on the anomalous production of W or Z bosons with large missing transverse momentum are set in two fiducial regions.

The Fourth Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope

Abstract: The fourth catalog of active galactic nuclei (AGNs) detected by the Fermi Gamma-ray Space Telescope Large Area Telescope (4LAC) between 2008 August 4 and 2016 August 2 contains 2863 objects located at high Galactic latitudes (|b|>10{\deg}). It includes 85% more sources than the previous 3LAC catalog based on 4 years of data. AGNs represent at least 79% of the high-latitude sources in the fourth Fermi-Large Area Telescope Source Catalog (4FGL), which covers the energy range from 50 MeV to 1 TeV. In addition, 344 gamma-ray AGNs are found at low Galactic latitudes. Most of the 4LAC AGNs are blazars (98%), while the remainder are other types of AGNs. The blazar population consists of 24% Flat Spectrum Radio Quasars (FSRQs), 38% BL Lac-type objects (BL Lacs), and 38% blazar candidates of unknown types (BCUs). On average, FSRQs display softer spectra and stronger variability in the gamma-ray band than BL Lacs do, confirming previous findings. All AGNs detected by ground-based atmospheric Cherenkov telescopes are also found in the 4LAC.