Thesis (M. Sc.)--University of Adelaide, 1994. / Includes bibliographical references (leaves 139-149).

Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains xvii, 146 p. : ill. (some col.). Includes abstract. Includes bibliographical references.

Thesis (Ph. D.) -- Lincoln University, 2004. / Also available via the World Wide Web.

No description available.

Thesis (MSc)--Stellenbosch University, 1981. / ENGLISH ABSTRACT: No abstract available / AFRIKAANSE OPSOMMING: Die aard, omvang en beheer van voelskade by wyndruiwe is ondersoek in die streek Stellenbosch - Simonsberg. Die Mossie (Passer melanurus, Willer) en die Europese spreeu (Sturnus vulgaris, Linnaeus) veroorsaak die meeste voelskade aan.wyndruiwe in die streek. Die kultivars gebruik in die ondersoek Was Chenin blanc, Pint noir, Riesling, Cinsaut, Clairette blanche en Cabernet Sauvignon. Die laagste suiker- en tic.ogsbasuurgehaltes waarby voelskade voorgehom het was onderskeidelik 11,2° Balling en 25,9g per l,- terwyl vreetskade by gemiddelde 12,4°. Balling en 19,1 g per l totale suur begin het. Die belangrikste enkele faktor wat t rol gespeel het by beskadiging was die suikerkonsentrasie. Die patroon van vreetskade oor t wingerdry is bepaal en het getoon dat die eerste 30 stokke aan weerskante van die wingerd die meeste beskadig word. 'n Metode is vasgestel cm die hoeveelheid skade aangerig te bepaal met behulp van tellings van beskadigde korrels in verteenwoordigende wingerdrye. Die skade in die streek is op 2,5% van die totale opbrengs per hektaar bepaal. Die bespuiting van wingerdblokke en alternatiewe buffer-kantrye met die afskrikmiddel metiokarb (Mesurol) teen 'n konsentrasie van 0,1% or genoemde kultivars, asook Muskadel, het onvoldoende beheer gebied. Bespuitings teen hoer konsentrasies word aanbeveel.

Thesis (MSc)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: The African penguin, which occurs along the south-eastern and south-western shores of South-Africa and Namibia, has experienced a severe reduction in population numbers due to guano and egg collection in the first half of the 19th century, and oil pollution in the second half of the 19th century as a result of oil tankers rounding the Cape of Good Hope. The population would have been reduced by a further 19% had it not been for the rehabilitation of penguins at the South African National Council for the Conservation of Coastal Birds (SANCCOB) facility. Although this has been very successful, mortalities as a result of avian malaria infection have considerably reduced the efficiency of rehabilitation. In an effort to assess the role of immunity against malaria in combating the disease, an enzyme-linked immunosorbent assay (ELISA) for the detection of antibody levels to avian malaria was developed. The ELISA was used to detect antibody levels to avian malaria of penguins on entry and during rehabilitation from October 2001 to January 2003. The aim of this study was to continue the determination of antibody levels to avian malaria of penguins entering the SANCCOB facility, in order to allow an evaluation of the antibody levels to avian malaria for two full calendar years. This investigation was combined with a polymerase chain reaction (PCR)-based method, capable of detecting any Plasmodium species in penguin serum. These two methods were also used to investigate avian malaria in several breeding colonies in order to assess the role avian malaria may play in the survival of the African penguin in the wild. Results indicated that the ability of penguins to produce anti-Plasmodium antibodies was not influenced by oiling and that infection with malaria was not due to recrudescence but rather due to infection via mosquitoes. This indicated a possible role of the SANCCOB facility in exposing the penguins to avian malaria. However a large number of penguins arrived at the facility previously infected with malaria, indicating that malaria was present in the breeding colonies. Investigations in the breeding colonies revealed extremely high avian malaria prevalence even though no sick birds or mortalities were observed. This raised the question whether different types of malaria are responsible for infection in the SANCCOB facility and breeding colonies. / AFRIKAANSE OPSOMMING: Die Afrika Pikkewyn kom langs die suid-oostelike en suid-westelike kus van Suid Afrika en Namibië voor. In die afgelope eeu het hierdie spesie ‘n geweldige afname in populasie getalle ondervind. Dit was hoofsaaklik die gevolg van die versameling van guano en pikkewyneiers in die eerste helfte van die 19de eeu en oliebesoedeling in die tweede helfde van die 19de eeu. Die “South African Foundation for Conservation of Coastal Birds” (SANCCOB) is ‘n seevoëlreddings- en rehabilitasiesentrum vir siek, beseerde en ge-oliede pikkewyne. Dit word geskat dat die Afrika Pikkewyn populasie met ‘n verdere 19% sou afgeneem het as dit nie vir die rehabilitasie by die SANCCOB sentrum was nie. Hierdie sentrum het egter aansienlike vrektes in die somer as gevolg van voëlmalaria, wat sodoende die effektiwiteit van die rehabilitasie verlaag. In ‘n poging om die rol van immuniteit teen malaria te bepaal is ‘n “enzyme-linked immunosorbent assay” (ELISA) ontwikkel vir die bepaling van antiliggaam vlakke teen malaria. Hierdie ELISA is gebruik vir die bepaling van die anti-Plasmodium antiliggaam vlakke van die pikkewyne by aankoms en ten tye van rehabilitasie by SANCCOB vanaf Oktober 2001 to Januarie 2003. Die doel van hierdie studie was eerstens om hierdie ELISA bepalings voort te sit om sodoende antiliggaam vlakke teen malaria oor twee kalender jare te kan evalueer. Hierdie ondersoek was gekombineer met ‘n polimerase ketting reaksie (PCR) metode, wat enige Plasmodium spesie in pikkewynserum sou kon opspoor. Hierdie twee metodes is ook gebruik vir ondersoeke in sommige broeikolonies, met die doel om te bepaal watter rol voëlmalaria in die oorlewing van die Afrika pikkewyn in die natuur speel. Resultate het getoon dat olie nie die vermoë van die pikkewyn beïnvloed om anti- Plasmodium antiliggame te vervaardig nie en dat malaria infeksie hoofsaaklik deur muskiete veroosaak word en nie deur heruitbraak van ‘n bestaande infeksie nie. Dit dui egter daarop dat pikkewyne blootgestel word aan voëlmalaria by die SANCCOB sentrum. Daar is ook gevind dat ‘n groot aantal pikkewyne met malaria infeksies by die sentrum opgedaag het wat dui op die voorkoms van malaria in die broeikolonies. Ondersoeke in die broeikolonies het ‘n besonder hoë voorkoms van malaria onthul. Geen vrektes of siek pikkewyne is in die broeikolonies waargeneem nie, wat moontlik kan beteken dat pikkewyne by SANCCOB met ‘n ander tipe malaria geïnfekteer word as in die broeikolonies.

This thesis discusses the results of an investigation that was initiated in January 1996 to determine the root cause of the increasing fault trend in respect of transient earth faults on the 275 kV transmission grid in KwaZulu-Natal, South Africa. Historically it was thought that the persistently poor performance of this network was caused by pollution faults. This network was reinsulated with silicone composite insulators, and cane fire as well as veld fire management programmes were introduced. These projects did not result in a consistently decreasing fault trend on this 275 kV transmission grid. The burn marks caused by the power arcs, which were identified in this study, appeared to indicate that air gap breakdown was occurring. Birds were also observed in close proximity to the faulted towers. Consequently it was thought that bird streamers caused the transmission line faults. Welded rod bird guards designed to prevent bird streamer faults were installed on eighteen 275 kV transmission lines. The accumulative length of these transmission lines is 932 km. The implementation of this initiative coincided with a 73% reduction in the total number of transient earth faults. This improvement in performance indicates a strong statistical correlation showing that a large number of the transient earth faults on the transmission grid are related to bird streamers. Bird streamer induced faults were identified by means of the following diagnostic techniques: • Burn mark analysis • Time-of-day analysis Bird streamer line faults have been observed on I string, V string and strain jumper assemblies on the 275 kV power lines. However, on the 400 kV power lines bird streamer faults have only been observed on V string assemblies. Experimental work involved simulated bird streamers and determining the minimum flashover distance for AC system voltages. Electric field measurements by means of a capacitive probe were undertaken at the ground plane. The electric field measurements at the ground plane under bird streamer intrusion confirm that if the streamer is moved away from the live tower hardware, the electric field enhancement at the ground plane decreases below the background streamer propagation field. This case study determined that in order to prevent bird streamer faults the bird streamer must be moved away from the live tower hardware. The distance it must be moved is at least 900 mm for 275 kV power lines and 1 100 mm for 400 kV lines. / Thesis (M.Sc.Eng.)-University of Natal, Durban, 2001.

In an effort to determine type, extent, and distribution of agricultural damage by blackbirds, county-wide damage appraisals were conducted in the fall of 1960. Crops checked included corn, peanuts, and milo. Based on the 96 fields examined throughout Nansemond County, the average monetary loss to the corn crop was slightly less than $.05 per acre. This loss can be reduced by planting a variety with a high degree of ear drooping and planting as early as possible. The peanuts appeared to be the crop most heavily damaged. An estimated 50 per cent of the crop was picked before blackbirds arrived. Of the part of the crop left exposed after the arrival of the blackbirds, only a small portion sustained damages amounting to above $5 per acre. By harvesting peanuts at an early date, losses to blackbirds can virtually be eliminated. The 1960 milo crop was not damaged by birds nearly so severely as previous crops were reported to have been. Anthracnose, a fungal disease, accounted for about 86 per cent of the damage previously called "bird damage." An estimated 15 per cent of this crop was destroyed by anthracnose, insects, and birds. In the case of all three crops, it was noted that the first and most severe damage was to those fields nearest nesting and roosting habitat. / Master of Science

This study was initiated to determine the effects of Herring Gulls (Larus argentatus) on the vegetation and soils of their nesting sites within the Mingan Island National Park Reserve. Both vegetation (species composition, cover, density, growth) and soil characteristics (pH, N, P, K, Ca, Mg) were monitored throughout the 1995 breeding season. Exclosures were installed within the colonies as control sites to prevent gull activity and these were compared to "treatment plots" or areas where gulls were present. All plants located at the study sites were native perennials with the exception of Stellaria, a native annual. Ledum groenlandicum was the only plant species significantly affected by gull activities. Both % cover and shoot growth for Ledum were greater in the exclosures than in the treatment plots over the breeding season. The gulls were also found to significantly increase pH and phosphorous levels in the soil through the deposition of faeces. Gull roosting sites were found to have higher nutrient levels than the nesting areas (treatment plots). The gulls appear to have minor effects over the short term, however the increases in soil nutrients may lead to significant changes over the long term. It is therefore imperative the exclosures remain in place to monitor for any long term changes which may occur.

No description available.