Efficient operator method for modeling mode mixing in misaligned optical cavities

The transverse field structure and diffraction loss of the resonant modes of Fabry-Pérot optical cavities are acutely sensitive to the alignment and shape of the mirror substrates. We develop extensions to the mode-mixing method applicable to arbitrary mirror shapes, which both facilitate fast calculation of the modes of cavities with transversely misaligned mirrors and enable the determination and transformation of the geometric properties of these modes. We show how these methods extend previous capabilities by including the practically motivated case of transverse mirror misalignment, presenting the ability to study the rich and complex structure of the resonant modes

Mode mixing and losses in misaligned microcavities

We present a study on the optical losses of Fabry-P\'erot cavities subject to realistic transverse mirror misalignment. We consider mirrors of the two most prevalent surface forms: idealised spherical depressions, and Gaussian profiles generated by laser ablation. We first describe the mode mixing phenomena seen in the spherical mirror case and compare to the frequently-used clipping model, observing close agreement in the predicted diffraction loss, but with the addition of protective mode mixing at transverse degeneracies. We then discuss the Gaussian mirror case, detailing how the varying surface curvature across the mirror leads to complex variations in round trip loss and mode profile. In light of the severe mode distortion and strongly elevated loss predicted for many cavity lengths and transverse alignments when using Gaussian mirrors, we suggest that the consequences of mirror surface profile are carefully considered when designing cavity experiments.Comment: 16 pages, 12 figure

Parasites of South African Wildlife. I. Helminths of bushbuck, Tragelaphus scriptus, and grey duiker, Sylvicapra grimmia, from the Weza State Forest, Natal

Thirteen bushbuck, Tragelaphus scriptus, and 13 grey duikers, Sylvicapra grimmia, were culled in the Weza State Forest, Natal, from May 1983-May 1984. The maximum number of worms recovered from a single bushbuck was 393. Of the total number of worms recovered from all the bushbuck, Paracooperia devossi were the most numerous, followed by Ostertagia harrisi, a Cooperia sp. and Haemonchus vegliai. P. devossi and O. harrisi were more numerous during winter and the Cooperia sp. more numerous during summer. Grey duiker harboured from 0-230 worms. The same Cooperia sp. as was recovered from the bushbuck and Trichostrongylus axei were the most numerous. The larvae of Taenia hydatigena were recovered from 5 duikers. The Coopena sp. was more numerous during summer and T. axei during winter, the remaining worms showing no seasonal pattern of abundance. Amended lists of the helminth parasites found in these antelope in the Republic of South Africa are provided.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu201

Parasites of South African wildlife. XIII. Helminths of grey rhebuck, Pelea capreolus, and of bontebok, Damaliscus dorcas dorcas, in the Bontebok National Park

A total of 25 grey rhebuck, Pelea capreolus, and 16 bontebok, Damaliscus dorcas dorcas, were shot for parasite recovery at bi-monthly intervals in the Bontebok National Park, south-western Cape Province, from February 1983 to December 1983 and February 1983 to February 1984, respectively. The grey rhebuck and the bontebok each harboured 9 nematode species and the latter animals 1 cestode species. Ostertagia hamata was most abundant and most prevalent in the grey rhebuck and Longistrongylus curvispiculum and Nematodirus spathiger in the bontebok. Longistrongylus schrenki is recorded for the first time in grey rhebuck, and Trichostrongylus falculatus and Moniezia expansa in bontebok. The total nematode burdens of the bontebok were considerably larger than those of the grey rhebuck. No clear pattern of seasonal abundance for the helminths of either host species was evident.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Council for Scientific and Industrial Research.mn201

Efficient operator method for modelling mode mixing in misaligned optical cavities

The transverse field structure and diffraction loss of the resonant modes of Fabry-P\'erot optical cavities are acutely sensitive to the alignment and shape of the mirror substrates. We develop extensions to the `mode mixing' method applicable to arbitrary mirror shapes, which both facilitate fast calculation of the modes of cavities with transversely misaligned mirrors and enable the determination and transformation of the geometric properties of these modes. We show how these methods extend previous capabilities by including the practically-motivated case of transverse mirror misalignment, unveiling rich and complex structure of the resonant modes.Comment: 17 pages, 7 figure

Parasites of South African wildlife. II. Helminths of kudu, Tragelaphus strepsiceros, from South West Africa/Namibia

A total of 23 kudu, Tragelaphus strepsiceros, were shot at 2-month intervals from June 1983 to April 1984 in the Etosha Game Reserve in the north of South West Africa/Namibia. The parasite survey conducted on these animals yielded 2 cestode and 12 nematode species. Haemonchus vegliai and Cooperia neitzi were the most prevalent nematodes and occurred in 13 animals each, followed by Cooperia acutispiculum and an Onchocerca sp. (9 animals each). The remaining nematodes were present in 4 (17 %) or fewer of the antelope. C. neitzi was the most numerous nematode, a total of 3 564 being recovered from all the antelope, followed by C. acutispiculum (2 552) and H. vegliai (1 050). Individual total worm burdens varied from 4-1 326 with 2 kudu harbouring no worms. The mean burden of 399 worms was considered negligible. A single kudu was shot in the Namib-Naukluft Park in the south of the country. This animal harboured no parasites.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201

Parasites of South African wildlife XII. Helminths of nyala, Tragelaphus angasii, in Natal

The helminths of 77 nyala, Tragelaphus angasii, from 4 game reserves in Natal, were collected, counted and identified. Ten nematode species and 4 nematode genera, a trematode species and paramphistomes, and 2 cestode genera were recovered from the antelope. Of these, a Cooperia rotundispiculum race, Gaigeria pachyscelis, a Gongylonema sp., Haemonchus vegliai, Impalaia tuberculata, an Oesophagostomum sp., a Setaria sp., Trichostrongylus deflexus, Trichostrongylus falculatus, the larval stage of a Taenia sp., a Thysaniezia sp. and Schistosoma mattheei are new parasite records for this host. Individual nematode helminth burdens varied from 3 to 13 493 and the total mean nematode burden was 700. The mean burdens of nyala from Mkuzi were the largest and those from animals from the Umfolozi Game Reserve and the False Bay Park the smallest. Ostertagia harrisi was the most prevalent nematode, and it was also the most numerous in nyala from Umfolozi, Mkuzi and False Bay. A race of Cooperia rotundispiculum was the most numerous in nyala from Ndumu. No clear-cut trends in the seasonal abundance could be discerned for any of the worm species recovered in this study.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Foundation for Research Development.mn201

Parasites of South African wildlife. IX. Helminths of kudu, Tragelaphus strepsiceros, in the eastern Cape Province

The helminths of 25 kudu, Tragelaphus strepsiceros, from 3 localities in the eastern Cape Province were collected, counted and identified. The majority of kudu harboured no worms, and the burdens of those infected were small. A race of Cooperia rotundispiculum, a Dictyocaulus sp., a Haemonchus sp., Nematodirus helvetianus and Ostertagia ostertagi were recovered. Two parasites, Nematodirus helvetianus and Ostertagia ostertagi can be added to the list of helminth parasites of kudu in South Africa.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.South African Nature Foundation. Foundation for Research Development.mn201

Cooperia connochaeti sp. nov. (Nematoda, Trichostrongylidae) from the blue wildebeest, Connochaetes taurinus (Burchell, 1823)

A new species of nematode, Cooperia connochaeti, was collected from cross-bred blue and black wildebeest at Krugersdorp (Transvaal), blue wildebeest Connochaetes taurinus (Burchell, 1823) from the Kruger National Park (Transvaal) and Lake Xhau (Botswana), as well as from impala Aepyceros melampus (Lichtenstein, 1812) at Malelane (Transvaal) and Pafuri (Kruger National Park). These nematodes are smaller than Cooperia pectinata Ransom, 1907, and their spicules, which are bifid in the distal third, are shorter (145-166 µm) than those of C. pectinata (240-280 µm). In addition, the lateral branches of the dorsal ray of C. connochaeti are directed ventrally and slightly anteriorly, while those of C. pectinata are directed posteriorly.This article has been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-Format

Parasites of domestic and wild animals in South Africa. XXXIV. Arthropod parasites of nyalas in north-eastern KwaZulu-Natal

Seventy-three nyalas (Tragelaphus angasii) in the Umfolozi, Mkuzi and Ndumu Game Reserves in northeastern KwaZulu-Natal were examined for arthropod parasites during 1983 and 1984. In addition, six animals were examined during 1994. Ten ixodid tick species, two louse species and a louse fly species were recovered. The nyalas were good hosts of all stages of development of Boophilus decoloratus, Rhipicephalus appendiculatus and Rhipicephalus muehlensi and the immature stages of Amblyomma hebraeum and Rhipicephalus maculatus. Adult male animals harboured more adult ticks, biting lice and louse flies than did adult females. B. decoloratus was generally most abundant from October to May. The larvae of R. appendiculatus peaked from April to October, nymphs from July to October and adults, on adult male nyalas, from February to May. Larvae of R. maculatus were most abundant from May to July and nymphs from June to October. The immature stages of A. hebraeum and all stages of R. muehlensi were present throughout the year.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Foundation for Research Development.mn201