Environmental variables, pesticide pollution and meiofaunal community structure in two contrasting temporarily open/closed false bay estuaries

Environmental variables (including natural and anthropogenic stressors) and meiobenthic communities were sampled in a ‘natural’ (Rooiels) and a ‘disturbed’ (Lourens) estuary in the Western Cape, South Africa, bimonthly for 20 months. A primary aim of the study was to assess if the meiobenthic community structure is driven by different variables when comparing ‘natural’ versus ‘disturbed’ system. Due to the much smaller catchment of the Rooiels Estuary, many environmental variables were significantly different (p<0.001) from the variables in the Lourens Estuary, e.g. salinity, temperature, pH, total suspended solids, nitrate and depth. No pesticide concentrations were expected in the Rooiels Estuary due to the absence of agricultural development in the catchment. However, chlorpyrifos (8.9 µg/kg), prothiofos (22.0 µg/kg) and cypermethrin concentrations (0.42 µg/kg) were detected frequently, with the highest concentrations recorded during the summer months. Principal response curve analysis showed that temporal variability between sampling dates explained 42% of the variance in environmental variables and pesticide concentrations and spatial variability between the 2 estuaries explained 58%. Variables contributing most to the differences were higher concentrations of endosulfan, p,p-DDE and nitrate concentrations in the Lourens Estuary and larger grain size and higher salinity at the bottom in the Rooiels Estuary. In general the meiofaunal community in the Rooiels Estuary showed a significantly higher number of taxa (p<0.001), a significantly higher Shannon Wiener Diversity Index (

Erratum

Original article: Day JA, Malan HL, Malijani E and Abegunde AP (2019) Water quality in non-perennial rivers. Water SA 45 (3) 487–500. https://doi.org/10.17159/ wsa/2019.v45.i3.6746 How to cite: Erratum: Water quality in non-perennial rivers. [Water SA 45 (3) 487–500]. Water SA 46 (2) 330–344. https://doi.org/10.17159/wsa.2020.v46i2.825

Review: Water quality in non-perennial rivers

More than half the river-lengths of rivers in southern Africa dry up occasionally or – more commonly – seasonally. Here we review the literature on water quality (WQ) in non-perennial rivers (N-PRs), with emphasis on river management and southern African systems. Hydrological regimes cover a spectrum from relatively predictable and unvarying in perennial rivers, to unpredictable and highly variable in non-perennial rivers, which are complex, continually shifting mosaics of flowing water, standing-water pools and terrestrial habitats. N-PRs are uncommonly difficult to manage because they represent a limited source of water that is renewed unpredictably and is competed for by local people as well as being required by wildlife. Groundwater, and therefore its chemical and physical features, contributes significantly to base flow and to the maintenance of pools remaining in the bed when the river is not flowing. Water chemistry reflects catchment geology except in polluted systems. Salinity varies temporally, and spatially over three dimensions, and is the variable controlling the composition of the biotas of many N-PRs. Hydrological regimes are seldom predictable with any certainty; WQ varies naturally over time and space; groundwater often determines the WQ of surface water, especially in pools; and WQ in non-perennial rivers and pools may be affected by activities far upstream in the catchment. As yet we have no more than a sketchy understanding of the extent to which data on any one system can be applied to any other. Until we have a better understanding of these systems, the following basic principles should guide the management of WQ in N-PRs: (i) Rivers need to be assessed on a case-by-case basis. (ii) Understanding of the groundwater regime, including its chemistry, is crucial. (iii) Effluents need to be controlled by conservative effluent standards set for both ground and surface waters. (iv) Flows may need to be augmented at certain times of the year.Keywords: non-perennial, rivers, water quality, review, water management, southern Afric

Psychological correlates of the UFO abduction experience : the role of beliefs and indirect suggestions on abduction accounts obtained during hypnosis

Reports of UFO abductions continue to increase in number in North America, the details of which are most commonly obtained in a quasi-therapeutic context, often involving hypnosis. In a series of studies at Concordia, we examined the phenomenology of these reports, the people who report them, and the roles which hypnosis and belief systems may play in such reports. Part 1 examined UFO abductees, and their experiences in the context of their hypnotizability, beliefs, and cognitive style. Our findings supplemented those of earlier studies (i.e., Spanos, 1987; Lawson, 1977) which indicated that, although abductees did not differ from the general population in terms of psychopathology, they did display different personality traits and cognitive styles prone to fantasy, conspiratorial thinking, and a higher degree of pre-existing beliefs in UFO-related phenomena. Part 2 examined the extent to which pre-hypnotic suggestions would be incorporated into hypnotic narratives of UFO abductions in a group of non-abductee volunteers. Suggestions resembling popular cultural aspects of abductions were incorporated into the hypnotic narratives of participants when they were asked to describe an imagined abduction experience. Part 3 examined the extent to which such simulated reports can be distinguished from the claims of bona fide abductees. Transcribed portions of both imaginary and putative actual abduction accounts were rated as being real or imagined by trained clinicians, and educated non-clinicians. The mean accuracy of the raters at distinguishing actual accounts from imagined was 51%, or chance level. The results are discussed in the context of memory distortion and confabulatory processes, and the potential role hypnosis plays in exacerbating these processes

Superscaling and Charge-changing Neutrino Cross Sections

The superscaling function extracted from inclusive electron scattering data is used to predict high energy charge-changing neutrino cross sections in the quasi-elastic and $\Delta$ regions.Comment: 3 pages, 2 figures, to appear in the Proceedings of the 7th International Workshop on Neutrino Factories and Superbeams, Laboratori Nazionali di Frascati, Frascati (Rome), June 21 - 26, 200

3D Printing of a Polymer Bioactive Glass Composite for Bone Repair

A major limitation of synthetic bone repair is insufficient vascularization of the interior region of the scaffold. In this study, we investigated the 3D printing of adipose derived mesenchymal stem cells (AD-MSCs) with polycaprolactone (PCL)/bioactive glass composite in a single process. This offered a three-dimensional environment for complex and dynamic interactions that govern the cell’s behavior in vivo. Borate based bioactive (13-93B3) glass of different concentrations (10 to 50 weight %) was added to a mixture of PCL and organic solvent to make an extrudable paste. AD-MSCs suspended in Matrigel was extruded as droplets using a second syringe. Scaffolds measuring 10x10x1 mm3 in overall dimensions with a filament width of ~500 μm and pore sizes ranging from 100 to 200 μm were fabricated. Strut formability dependence on paste viscosity, scaffold integrity, and printing parameters for droplets of ADMSCs suspended in Matrigel were investigated

Scaling and isospin effects in quasielastic lepton-nucleus scattering in the Relativistic Mean Field Approach

The role of isospin in quasielastic electron scattering and charge-changing neutrino reactions is investigated in the relativistic impulse approximation. We analyze proton and neutron scaling functions making use of various theoretical descriptions for the final-state interactions, focusing on the effects introduced by the presence of strong scalar and vector terms in the relativistic mean field approach. An explanation for the differences observed in the scaling functions evaluated from $(e,e')$ and $(\nu,\mu)$ reactions is provided by invoking the differences in isoscalar and isovector contributions.Comment: 10 pages, 5 figures, submitted to Phys. Lett.

Serum antioxidants as predictors of the adult respiratory distress syndrome in septic patients

Adult respiratory distress syndrome (ARDS) can develop as a complication of various disorders, including sepsis, but it has not been possible to identify which of the patients at risk will develop this serious disorder. We have investigated the ability of six markers, measured sequentially in blood, to predict development of ARDS in 26 patients with sepsis. At the initial diagnosis of sepsis (6-24 h before the development of ARDS), serum manganese superoxide dismutase concentration and catalase activity were higher in the 6 patients who subsequently developed ARDS than in 20 patients who did not develop ARDS. These changes in antioxidant enzymes predicted the development of ARDS in septic patients with the same sensitivity, specificity, and efficiency as simultaneous assessments of serum lactate dehydrogenase activity and factor VIII concentration. By contrast, serum glutathione peroxidase activity and α1Pi-elastase complex concentration did not differ at the initial diagnosis of sepsis between patients who did and did not subsequently develop ARDS, and were not as effective in predicting the development of ARDS. Measurement of manganese superoxide dismutase and catalase, in addition to the other markers, should facilitate identification of patients at highest risk of ARDS and allow prospective treatment

Superscaling analysis of the Coulomb Sum Rule in quasielastic electron-nucleus scattering

The Coulomb sum rule for inclusive quasielastic electron scattering in $^{12}$C, $^{40}$Ca and $^{56}$Fe is analyzed based on scaling and superscaling properties. Results obtained in the relativistic impulse approximation with various descriptions of the final state interactions are shown. A comparison with experimental data measured at Bates and Saclay is provided. The theoretical description based on strong scalar and vector terms present in the relativistic mean field, which has been shown to reproduce the experimental asymmetric superscaling function, leads to results that are in fair agreement with Bates data while it sizeably overestimates Saclay data. We find that the Coulomb sum rule for a momentum transfer $q\geq 500$ $MeV/c$ saturates to a value close to 0.9, being very similar for the three nuclear systems considered. This is in accordance with Bates data, which indicates that these show no significative quenching in the longitudinal response.Comment: 22 pages, 6 figures. To be published in Phys. Lett.