Complex, Dynamic Combination of Physical, Chemical and Nutritional Variables Controls Spatio-Temporal Variation of Sandy Beach Community Structure

Sandy beach ecological theory states that physical features of the beach control macrobenthic community structure on all but the most dissipative beaches. However, few studies have simultaneously evaluated the relative importance of physical, chemical and biological factors as potential explanatory variables for meso-scale spatio-temporal patterns of intertidal community structure in these systems. Here, we investigate macroinfaunal community structure of a micro-tidal sandy beach that is located on an oligotrophic subtropical coast and is influenced by seasonal estuarine input. We repeatedly sampled biological and environmental variables at a series of beach transects arranged at increasing distances from the estuary mouth. Sampling took place over a period of five months, corresponding with the transition between the dry and wet season. This allowed assessment of biological-physical relationships across chemical and nutritional gradients associated with a range of estuarine inputs. Physical, chemical, and biological response variables, as well as measures of community structure, showed significant spatio-temporal patterns. In general, bivariate relationships between biological and environmental variables were rare and weak. However, multivariate correlation approaches identified a variety of environmental variables (i.e., sampling session, the C:N ratio of particulate organic matter, dissolved inorganic nutrient concentrations, various size fractions of photopigment concentrations, salinity and, to a lesser extent, beach width and sediment kurtosis) that either alone or combined provided significant explanatory power for spatio-temporal patterns of macroinfaunal community structure. Overall, these results showed that the macrobenthic community on Mtunzini Beach was not structured primarily by physical factors, but instead by a complex and dynamic blend of nutritional, chemical and physical drivers. This emphasises the need to recognise ocean-exposed sandy beaches as functional ecosystems in their own right

It often howls more than it chugs: Wind versus ship noise under water in Australia’s maritime regions

Marine soundscapes consist of cumulative contributions by diverse sources of sound grouped into: physical (e.g., wind), biological (e.g., fish), and anthropogenic (e.g., shipping)—each with unique spatial, temporal, and frequency characteristics. In terms of anthropophony, shipping has been found to be the greatest (ubiquitous and continuous) contributor of low-frequency underwater noise in several northern hemisphere soundscapes. Our aim was to develop a model for ship noise in Australian waters, which could be used by industry and government to manage marine zones, their usage, stressors, and potential impacts. We also modelled wind noise under water to provide context to the contribution of ship noise. The models were validated with underwater recordings from 25 sites. As expected, there was good congruence when shipping or wind were the dominant sources. However, there was less agreement when other anthropogenic or biological sources were present (i.e., primarily marine seismic surveying and whales). Off Australia, pristine marine soundscapes (based on the dominance of natural, biological and physical sound) remain, in particular, near offshore reefs and islands. Strong wind noise dominates along the southern Australian coast. Underwater shipping noise dominates only in certain areas, along the eastern seaboard and on the northwest shelf, close to shipping lanes

Preterm labour - Is Mycoplasma hominis involved?

Objective. To assess whether Mycoplasma hominis is associated with preterm labour in primigravidae  and multigravidae with previous midtrimester abortion or preterm labour.Design. Cohort analytical study. Setting. Tygerberg Hospital, a tertiary academic hospital in the Western Cape.Methods. Gram's stains were done on smears taken from the posterior vaginal fornix, at the first  antenatal visit, between 16 and 26 weeks' gestation, in primigravidae and multigravidae at risk for preterm labour. Cultures for M. hominis and other commonly occurring organisms were done ·from endocervical swabs taken at the same visit. The outcome of pregnancy in mothers with positive cultures for M. hominis was then compared with outcome in women with negative cultures.Outcome measures. Prevalence of Chlamydia trachomatis, Ureaplasma urealyticum, bacterial vaginosis and preterm delivery, birth weight and perinatal deaths.Results. Cultures for M. hominis were positive in 83 patients  (21 %) and negative in 312 (79%).  Significantly more mothers in the positive group (40%) delivered before 37 weeks' gestation than in the negative group (28%, P = 0.0313). Their babies weighed significantly less (2 669 g v. 2 864 g, P = 0.0141). The positive group was also associated with more alcohol use in pregnancy and fewer of them  were married. C. trachomatis was found in 18% of mothers in the positive group but in 8% of the negative group (P = 0.0082). U. urealyticum was cultured in 96% of mothers in the positive group in contrast to 81 % in the negative group (P = 0.001). Bacterial vaginosis was observed on 75% of mothers  with positive cultures for M. hominis but in 22% with negative cultures (P = 0.00001, odds ratio 10.21, 95% confidence interval: 5.63 - 18.65). Conclusion. Positive culture for M. hominis was associated with more preterm deliveries and also with a higher frequency of C. trachomatis, U. urealyticum and bacterial vaginosis

Corporate governance structures : the balancing act performed by South African financial services companies.

Thesis (MBA.)-University of Natal, 2002.No abstract available

Usable pasts forum: critically engaging food security

In this inaugural Usable Pasts Forum, we make the case that archaeology has a critical role to play in reframing approaches to food security in the African continent

Practical management of therapeutic diphenylhydantoin concentrations in children

Objective. Development of easy, practical methods for the management and optimisation of therapeutic diphenylhydantoin (DPH) concentrations in children.Design. Investigation of DPH concentration profiles and pharmacokinetic parameters in children with poorly controlled epilepsy. Subsequent determination of individual-specific DPH maintenance dosage and volume of distribution data suitable for use in routine therapeutic concentration management procedures.Setting. Department of Paediatrics and Child Health and Department of Pharmacology, University of Stellenbosch, Tygerberg Hospital.Subjects. Children of both sexes between the ages of 4 and 12 years with poorly controlled epilepsy receiving DPH as sole medication.Results. In all subjects evaluated epilepsy was unsatisfactorily controlled because of inadequate DPH dosage regimens. Individual-specific maintenance dosage and volume of distribution data could be calculated for all individuals participating in the trial. The calculated data were· suitable for use in routine management procedures and in no instance was it necessary to recalculate parameters in a 12-month follow-up period subsequent to evaluation.Conclusions. Therapeutic DPH concentration profiles can be managed satisfactorily in children if individual-specific DPH pharmacokinetic parameters are derived and skilfully applied

Preterm labour - is bacterial vaginosis involved?

Objective. To assess the efficacy of treatment of bacterial vaginosis (BV) using metronidazole to reduce  preterm labour in primiravidae and multigravidae with previous midtrimester abortion or preterm labour.Design. Randomised controlled trial.Setting. Tertiary academic hospital.Method. Two different groups of patients were screened for BV at the first antenatal visit, namely  primigravidae and high-risk multigravidae who had had a previous midtrimester abortion or preterm delivery. Patients where BV was diagnosed clinically or on Gram's stain of a smear taken from the posterior vaginal fornix, received either 400 mg metronidazole, or 100 mg vitamin C orally twice daily for 2 days. The Gram's stain was repeated after 4 weeks. If BV W?S found again, treatment with the same  drug was repeated.Outcome measures. Preterm delivery, birth weight and perinatal deaths.Results. One thousand and five patients entered the study, but 40 were excluded for various reasons and 10 were lost to follow-up. There were 464 primigravidae, of whom 150 (32%) had BV. Except for the 5-minute Apgar score, no significant differences were found between primigravidae negative for BV and those who received either metronidazole or vitamin C. There were 491 high-risk multigravidae, of whom 127 (26%) had BV. The mean gestational age in the BVnegative group was 37 weeks, in contrast to 37.4 weeks in the vitamin C group and 35.6 weeks in the metronidazole group. Birth weights in these three groups were 2 752 g, 2 759 g and 2 475 g respectively, significantly less (P == 0.0109) in the  metronidazole group in comparison with the BV-negative group. Delivery before 37 weeks occurred in 29% of high-risk multigravidae with no BV but in 24% of those who took  vitamin C and in 43% who took metronidazole. Differences were significant between the BV-negative and metronidazole groups (P = 0.0231) and also between the metrol'.idazole and vitamin C groups (P = 0.0274). Delivery before 28 weeks occurred in 4% of the high-risk multigravidae with no UV but in 10% of those with BV who took metronidazole. The difference was significant (P =0.0430). Analysis for maximum likelihood estimates for preterm labour identified only previous preterm labour or midtrimester abortion as risk factors.Conclusion. Metronidazole does not seem to reduce the prevalence of preterm labour when given for BV before 26 weeks' gestation

The air quality perceptions of the residents of Bayview, Mossel Bay

Background: In developing countries, it often occurs that little attention is given to air pollution emissions due to a lack of proper town planning, household combustion processes, energy production and the continuous growth in the transport sector (Norman et al., 2007:783). There is an increase in urban air pollution in most of the major cities of developing countries which is amplified by population growth and industrialization (World Resource Institute, 1998, 1999:1). Air pollution studies are not complete, and may fail if the quality of life and the perceptions of the studied community are not taken into consideration. This paper investigates the air quality perceptions of a high income residency surrounded by industrial activities and Mossel Bay was rated as to have potentially poor air quality by the South African Department of Environmental Affairs and Tourism. Methods: A cross-sectional survey was carried out in Bayview, Mossel Bay. The perceptions of the respondents were collected by a structured questionnaire. Components of perceptions that were tested included general opinion regarding air quality, visual perceptions of air quality, type of pollutants such as smoke and dust, perceptions regarding the source of air pollution, perceptions regarding the municipal health institution controlling air quality in Bayview, etc. These perceptions were investigated by age, gender, socio-economic status etc

Sandy beaches at the brink

Sandy beaches line most of the world’s oceans and are highly valued by society: more people use sandy beaches than any other type of shore. While the economic and social values of beaches are generally regarded as paramount, sandy shores also have special ecological features and contain a distinctive biodiversity that is generally not recognized. These unique ecosystems are facing escalating anthropogenic pressures, chiefly from rapacious coastal development, direct human uses — mainly associated with recreation — and rising sea levels. Beaches are increasingly becoming trapped in a ‘coastal squeeze’ between burgeoning human populations from the land and the effects of global climate change from the sea. Society’s interventions (e.g. shoreline armouring, beach nourishment) to combat changes in beach environments, such as erosion and shoreline retreat, can result in severe ecological impacts and loss of biodiversity at local scales, but are predicted also to have cumulative large-scale consequences worldwide. Because of the scale of this problem, the continued existence of beaches as functional ecosystems is likely to depend on direct conservation efforts. Conservation, in turn, will have to increasingly draw on a consolidated body of ecological theory for these ecosystems. Although this body of theory has yet to be fully developed, we identify here a number of critical research directions that are required to progress coastal management and conservation of sandy beach ecosystems