4 research outputs found
Groundwater Dependence of Aquatic Ecosystems associated with the Table Mountain Group Aquifer
Philosophiae Doctor - PhDResults from this study enables a better understanding of groundwater surface water interactions in the TMG, particularly regarding aquatic ecosystems. It has also highlighted the necessity to do proper impact assessments before proceeding with bulk abstraction from this important aquifer. The results also demonstrated the importance of differentiating between real groundwater and non-groundwater discharge contributions to surface hydrology and where these interface areas are located.South Afric
Independent formant and pitch control applied to singing voice
Thesis (MScIng)--University of Stellenbosch, 2004.ENGLISH ABSTRACT: A singing voice can be manipulated artificially by means of a digital computer for the
purposes of creating new melodies or to correct existing ones. When the fundamental frequency
of an audio signal that represents a human voice is changed by simple algorithms,
the formants of the voice tend to move to new frequency locations, making it sound unnatural.
The main purpose is to design a technique by which the pitch and formants of a
singing voice can be controlled independently.AFRIKAANSE OPSOMMING: Onafhanklike formant- en toonhoogte beheer toegepas op ’n sangstem: ’n Sangstem kan
deur ’n digitale rekenaar gemanipuleer word om nuwe melodie¨e te skep, of om bestaandes
te verbeter. Wanneer die fundamentele frekwensie van ’n klanksein (wat ’n menslike stem
voorstel) deur ’n eenvoudige algoritme verander word, skuif die oorspronklike formante
na nuwe frekwensie gebiede. Dit veroorsaak dat die resultaat onnatuurlik klink. Die hoof
oogmerk is om ’n tegniek te ontwerp wat die toonhoogte en die formante van ’n sangstem
apart kan beheer
Groundwater discharges to aquatic ecosystems associated with the Table Mountain Group (TMG) aquifer: a conceptual model
This paper reports on a conceptual model that was developed to describe the different groundwater discharge ‘types’ from
the Table Mountain Group (TMG) aquifer, that contributes to the different components of the flow regime in each of the recognised river reaches for streams and rivers associated with the TMG. This model integrates hydrogeological, ecological and
geomorphological understandings into an ecohydrological perspective linking ground- and surface water systems. Through
geospatial intersections of existing GIS layers a GIS model was also developed to highlight the quaternary catchments containing sensitive aquatic ecosystems that could be vulnerable to groundwater use from the TMG. The conceptual model demonstrates the intimate link between groundwater from the TMG aquifer and aquatic ecosystems in the mountain and foothill reaches of streams and rivers in the Cape Folded Mountains in particular. It also identifies
two primary zones of interaction between groundwater and surface water in the TMG, namely, the ‘TMG aquifer daylight-
domain’, located in the recharge zone, and the ‘TMG aquifer surface water interface-domain’, located at the discharge end of
the aquifer. The conceptual model clearly indicates the difference between real groundwater, and perceived groundwater contributions to streamflow in the TMG. It is the lower flows of the flow regime that will be most vulnerable to groundwater use from
the TMG aquifer in the ‘TMG aquifer daylight-domain’, which are unfortunately also the most important flows from an
ecological perspective. However, any groundwater use from the TMG aquifer will also affect the discharge end of the aquifer,
located far from the higher elevation recharge areas, or the point of groundwater abstraction, in lowland settings in the ‘TMG
aquifer surface water interface-domain’. The GIS model integrated the conceptual understanding into a management tool by highlight all quaternary catchments
associated with TMG containing sensitive aquatic ecosystems and gave the variable vulnerability for each.Web of Scienc
Korttermynbedreigings vir varswater–Mollusca in die Olifantsrivier en enkele sytakke
Short-term threats for the sustained survival of freshwater Mollusca in the Olifants River
and selected tributaries. The conservation status of less than 2% of the more or less 7000
mollusk species known worldwide have been properly assessed. Consequently the general
level of imperilment is poorly documented and almost certainly underestimated. Freshwater
mollusks live permanently in water, have limited means of movement and are exposed to a
variety of anthropogenic waste products due to the fact that waterbodies often act as sinks for
a large array of harmful pollutants. The Olifants River is often described as one of the most
polluted rivers in Southern Africa and is progressively subjected to extremely high pressure
with regard to natural resources and associated rural transformation and pollution. Little is on
record regarding the diversity of the Mollusca in the Olifants River; therefore, in the present
study, four surveys of the molluscs were conducted in this river and selected tributaries during
two consecutive years at three localities situated on the Highveld and four localities situated
in the Lowveld respectively. The pH and electric conductivity of the water were determined
during each survey at each one of the localities and values ranged from 6.93 to 9.50, and 110 μS
to 1336 μS, for pH and conductivity respectively. A total of 25 mollusk species were collected
during the four surveys which included the exotic invader species Lymnaea columella, Physa
acuta, Aplexa marmorata and Tarebia granifera. The latter species yielded the highest number of
specimens by far, mainly at a locality which could be described as largely transformed. The
results of this investigation can serve as a point of departure for future surveys to evaluate
the impact of anthropogenic disturbances on the mollusc diversity in the Olifants River and
catchmenthttp://www.satnt.ac.za/index.php/satnt/issue/archivehttp://www.satnt.ac.za/index.php/satnt/article/view/39