Die radio in Afrika

Omvang van radio-uitsendings in en na Afrika. — Redes vir die versnelde tempo van uitbreiding. — Radio as die geskikste massa-kommunikasiemiddel vir Afrika. — Faktore wat die verspreiding bemoeilik. — Skouspelagtige toename in luistertalle.Toe Plinius, wat in die jaar 79 oorlede is, in sy „Historia Naturalis” verklaar het dat daar altyd iets nuuts uit Afrika afkomstig is, kon hy nouliks voorsien het dat die „iets" negentien eeue later in die lug sou setel wat hierdie reuse-vasteland oorspan — ’n Babelse spraakverwarring en ’n ongekende, verbete woorde-oorlog in die etergolwe, onder meer daarop bereken om die harte en hoofde van derduisendes te verower

Seasonal and interannual variability in phytoplankton biomass on the southern African continental shelf: evidence from satellite-derived pigment concentrations

Surface ocean phytoplankton biomass variability on the southern African continental shelf area is investigated using coastal zone colour scanner data for the period 1979–1986. Coherent interannual trends in surface ocean chlorophyll for both the west coast Benguela and the south coast Agulhas Bank areas correspond with sea surface temperature records, rather than with local records of upwelling-favourable winds. This finding implies that interannual variability in phytoplankton biomass, in contrast to the well-established seasonal cycle, is associated with large-scale oceanic circulation features and forcing mechanisms, rather than with localized upwelling events. The most probable causative mechanism is suggested to be anomalous advective fluxes of warm surface water into areas typically of high biomass deriving from the Agulhas Current retroflection in the south. Studyingvariability in phytoplankton biomass on the continental shelf in the context of large-scale oceanic circulation features is important to understanding long-term trends in productivity and fisheries resources

Recognition of neotype specimens for species described from the Arnot Pipe, Banke, Namaqualand, South Africa

Important palynological studies were completed by Scholtz (1985) on material from the Arnot Pipe on the farm Banke in Namaqualand, Northern Cape Province. The results comprised a rare record of early Tertiary vegetation in southern Africa. The body of Scholtz’s research consisted of systematic, descriptive palynology including the description of one new genus and fifteen new species. Ongoing research into South Africa’s Tertiary palynology requires that the type specimens from Arnot be used for comparative purposes. However, the microscope slides on which they were founded were not available for examination. Another set of slides, representing two of the seven samples taken at Arnot, was used to search for neotype specimens to replace the missing holotypes. Specimens representing all fifteen new species were found, but were often badly preserved, obscured by debris or trapped between air bubbles as the condition of the decade-old microscope slides had deteriorated. Only specimens in good condition were selected as neotypes, and comprehensively illustrated. Four of Scholtz’s new species were transferred to alternative, more applicable, genera.The Council's Research Committe, University of the Witwatersrand; National Science Foundatio

Has monitoring failed the Olifants River, Mpumalanga?

Water quality monitoring in the Olifants River catchment, Mpumalanga, is evaluated using river water dissolved sulphate levels, one of the best indicators of pollution related to acid mine drainage. Assessment of long-term water quality records shows that monitoring has not been carried out systematically. In that it fails one of the most fundamental criteria of good environmental monitoring practices. At some monitoring stations sampling frequency has been scaled down from approxi-mately weekly to monthly intervals over time, despite evidence for increasing and problematic levels of pollution. At the Loskop Dam dissolved sulphate levels have increased more than 7-fold since the 1970s evidently due to increasing levels of pollution within the Little Olifants River catchment. At 4 of the 7 long-term monitoring stations river water sulphate levels exceed the 100 mg/. threshold value for aquatic ecosystem health most of the time for the duration of the record, and all of the time since about 2001. At these stations river water sulphate levels also exceed the 200 mg/. threshold for humanconsumption 27 to 45% of the time, for the duration of the long-term record. These observations necessitate more frequent and improved monitoring, not evidently reduced efforts. A major concern is the location of a recently re-opened copper mine outside Phalaborwa, just upstream from the confluence of the Ga-Selati River and the Olifants River. Levels of copper sulphate, highly toxic to aquatic species, should be urgently investigated as a probable cause of recent fish and crocodile deaths in the Kruger National Park. In river systems subject to intensive mining activity, such as the Olifants River, toxicconstituents such as copper, arsenic, chrome-VI, etc., currently not routinely measured by the Department of Water Affairs(DWA) need to be included in monitoring efforts as a matter of urgency. This will require drastic improvements in current water quality monitoring efforts, including the acquisition of modern analytical instrumentation

The palynology of tertiary sediments from a palaeochannel in Namaqualand, South Africa.

Main articleA site in amaqualand, Western Cape Province, has yielded a diverse and well-preserved pa lynoflora. The site consists of a quarry, exposing a palaeochannel containing fluviatile sands, silts and clays with accompanying peat horizons. This paper presents a qualitative account of the pollen and pore assemblages extracted from the peats. Ang iosperms were dominant both in terms of the number of individuals and the recognised types. Identification were made where possible with reference to published illustrations and descriptions. There was a total of 69 palynomorph types, including spores, gymnosperm and angiosperm pollen.Non

Prevalence and characteristics of erectile dysfunction in black and mixed race primary care populations of the Cape Flats and Helderberg Basin area of the Western Cape, South Africa

Objective: To estimate the prevalence of erectile dysfunction (ED) among users of primary care in a Black and Mixed Race urban population in the Western Cape, and to describe any associated health and psychosocial factors. Design: Cross-sectional survey by interviewer administered questionnaire. Setting: Two primary care medical centres, 40km apart, in Cape Town metropolitan area. Serve different ethnic groups, with no cross-contamination between them. Study period: March-June 1999 Patients: 833 Males (35-70 years old) attending these health centres for primary care. Systematic selection of all attendees. Main outcome measures: Prevalence of ED and presence of associated health and psychosocial factors. Describe patient demographics, physical attributes, sexual relationships. Results: Results of 730 males with current sexual partners: Mean ages 48 years (SD:7 years) all; 46 years (SD:9 years) Black group; 51 years (SD: 9 years) Mixed Race group. All degrees of ED prevalence: All 77.1% (95% CI: 74.0-80.2), Black 76.4% (95% CI: 71.8-80.4) and Mixed Race 77.7% (95% CI: 72.8-82.0). Significantly associated diseases: hypertension, diabetes, gastrointestinal and heart disease. Alcohol consumption (younger patients), smoking (older patients) significantly related to ED. Males with ED: more sexual partners than males without ED. More than 90% choose primary care physician/ generalist as primary ED care-giver. Conclusions: ED is very common in both study groups. Primary care workers must be prepared to manage associated risk factors and health implications. ED sufferers in this population may also be at higher risk for sexually transmitted diseases due to multiple sexual partners. (SA Fam Pract 2003;45(1):14-20) Keywords: erectile dysfunction, impotence, prevalence, black

Die meting van die verband tussen geslag en konformiteit as groepdinamiese veranderlikes

The original publication is available at http://www.sajip.co.zaThe amount and kind of conformity induced by group pressure depend upon the nature of the situation. The nature of the group and the characteristics of the individual. In this particular study the experimental measurement of conformity developed by Asch and Crutchfield was repeated. Confirmation was found that sex operates as one of the determinants of conformity.Publishers' Versio