A combination of statistical methods for the analysis of the relative validation data of the quantitative food frequency questionnaire used in the THUSA study. Transition, Health and Urbanisation in South Africa     

MacIntyre UE  Venter CS  Vorster HH  Steyn HS 《Public health nutrition》2001,4(1):45-51

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^99mTc-METHOXY-ISOBUTYL-ISONITRILE (SESTAMIBI) IMAGING OF MALIGNANT CANINE LYMPHOMA     

Phillip F.  Steyn  BVSc  MRCVS  MS  Gregory  Ogilvie  DVM 《Veterinary radiology & ultrasound》1995,36(5):411-416

Technetium-99m methoxy-isobutyl-isonitrile (sestamibi) imaging of malignant canine lymphoma was performed in thirteen dogs 1 hour after intravenous injection of ^99mTc-sestamibi at 13 MBq (0.35 mCi) per kilogram body weight. Abnormal tracer uptake was visualized in the liver, spleen, bone marrow, and mesenteric, inguinal, popliteal, sternal, cranial cervical and mandibular lymph nodes. Radiopharmaceutical uptake was also noted in a nasal mass. One large neoplastic renal mass did not have demonstrable sestamibi uptake. Other regions had no significant difference in the target:background ratios when compared with values from normal dogs ( P > 0.05). ^99mTc-sestamibi can be used to image malignant lymphoma, and has potential applications in the management of patients to document response to treatment and to stage of extent of disease.  相似文献   

Occupation and Use of the Eucalyptus Plantations in the Tzaneen Area by Indigenous Birds / OKKUPASIE EN GEBRUIK VAN DIE EUCALYPTUS PLANTASIES IN DIE TZANEEN AREA DEUR INHEEMSE VOËLS     

D. J. Steyn 《Southern Forests》2013,75(1):56-60

The eucalyptus plantations, mainly Eucalyptus grandis, which cover large areas in the North-eastern Transvaal are usually accused of being sterile and unsuitable for birdlife. This supposition is exaggerated and proved to be wrong. One must admit, however, that some less adaptable birds which occur in the area, and which must have inhabited the planted area prior to the establishment of plantations have been driven out. Plantations are obviously completely unsuited to the mode of life of certain birds for various reasons. The most obvious example in this area is the fruit-eating purple-crested lourie (Gallirex porphyreolopus) which is very seldom seen in a plantation. Other species which prefer open country for example widow birds and bishop birds, and certain larks and pipits have also of necessity moved out.  相似文献   

Climate Change and Potato Production in Contrasting South African Agro-Ecosystems 3. Effects on Relative Development Rates of Selected Pathogens and Pests     

J. E. van der Waals  K. Krüger  A. C. Franke  A. J. Haverkort  J. M. Steyn 《Potato Research》2013,56(1):67-84

A set of daily weather data simulations for 1961 to 2050 were used to calculate past and future trends in pest and disease pressure in potato cropping systems at three agro-ecologically distinct sites in South Africa: the Sandveld, the Eastern Free State and Limpopo. The diseases and pests modelled were late blight, early blight and brown spot, blackleg and soft rot, root-knot nematodes and the peach-potato aphid Myzus persicae (as indicator of Potato virus Y and Potato leaf roll virus). The effects of climate on trends in relative development rates of these pathogens and pests were modelled for each pathogen and pest using a set of quantitative parameters, which included specific temperature and moisture requirements for population growth, compiled from literature. Results showed that the cumulative relative development rate (cRDR) of soft rot and blackleg, root-knot nematodes and M. persicae will increase over the 90-year period in the areas under consideration. The cRDR of early blight and brown spot is likely to increase in the wet winter and wet summer crops of the Sandveld and Eastern Free State, respectively, but remains unchanged in the dry summer and dry winter crops of the Sandveld and Limpopo, respectively. Climate change will decrease the cRDR of late blight in all of the cropping systems modelled, except in the wet winter crop of the Sandveld. These results help to set priorities in research and breeding, specifically in relation to management strategies for diseases and pests.  相似文献   

Vascular Endothelial (VEGF) and Epithelial Growth Factor (EGF) as Well as Platelet‐Activating Factor (PAF) and Receptors are Expressed in the Early Pregnant Canine Uterus     

S Schäfer‐Somi  S Sabitzer  D Klein  E Reinbacher  H Kanca  HB Beceriklisoy  OA Aksoy  I Kucukaslan  HC Macun  S Aslan 《Reproduction in domestic animals》2013,48(1):20-26

The aim of this study was to investigate the course of expression of platelet‐activating factor (PAF), PAF‐receptor (PAF‐R), epidermal growth factor (EGF), EGF‐R, vascular endothelial growth factor (VEGF), VEGF‐R1 and VEGF‐R2 in uterine tissue during canine pregnancy. For this purpose, 20 bitches were ovariohysterectomized at days 10–12 (n = 10), 18–25 (n = 5) and 28–45 (n = 5) days after mating, respectively. The pre‐implantation group was proven pregnant by embryo flushing of the uterus after the operation, the others by sonography. Five embryo negative, that is, non‐pregnant, bitches in diestrus (day 10–12) served as controls. Tissue samples from the uterus (placentation sites and horn width, respectively) were excised and snap‐frozen in liquid nitrogen after embedding in Tissue Tec^®. Extraction of mRNA for RT‐PCR was performed with Tri‐Reagent. In the embryos, mRNA from all factors except VEGF was detected. In the course of pregnancy, significantly higher expression of PAF and PAFR as well as VEGF and VEGFR2 during the pre‐implantation stage than in all other stages and a strong upregulation of EGF during implantation were characteristic. The course of EGF was in diametrical opposition to the course of the receptor. These results point towards an increased demand for VEGF, EGF and PAF during the earliest stages of canine pregnancy.  相似文献   

Challenges for efficient health service delivery: experiences of dietitians completing their compulsory community service year in South Africa     

Parker WA  Steyn NP  Mchiza Z  Wentzel-Viljoen E  Dannhauser A  Mbhenyane X  Nthangeni G  Moeng L 《Public health nutrition》2012,15(8):1411-1418

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Plant disease management in organic farming systems          下载免费PDF全文

Ariena HC van Bruggen  Abraham Gamliel  Maria R Finckh 《Pest management science》2016,72(1):30-44

Organic farming (OF) has significantly increased in importance in recent decades. Disease management in OF is largely based on the maintenance of biological diversity and soil health by balanced crop rotations, including nitrogen‐fixing and cover crops, intercrops, additions of manure and compost and reductions in soil tillage. Most soil‐borne diseases are naturally suppressed, while foliar diseases can sometimes be problematic. Only when a severe disease outbreak is expected are pesticides used that are approved for OF. A detailed overview is given of cultural and biological control measures. Attention is also given to regulated pesticides. We conclude that a systems approach to disease management is required, and that interdisciplinary research is needed to solve lingering disease problems, especially for OF in the tropics. Some of the organic regulations are in need of revision in close collaboration with various stakeholders. © 2015 Society of Chemical Industry  相似文献   

Host suitability and response of different vegetable genotypes to Meloidogyne incognita race 2 and Meloidogyne javanica in South Africa     

W.P. Steyn  M.S. Daneel  M.M. Slabbert 《国际虫害防治杂志》2014,60(1):59-66

The host suitability of 20 locally available genotypes of Capsicum, 10 of Daucus carota, 7 of Beta vulgaris- and 3 of Spinacea oleracea were assessed in separate greenhouse studies for resistance to Meloidogyne incognita race 2 and M. javanica, respectively. Substantial variation existed amongst the vegetable genotypes in the greenhouse screenings with regard to their host status to the respective root-knot nematode species. None of the genotypes of D. carota, B. vulgaris and S. oleracea showed resistance to the nematode species tested. However, resistance to M. incognita race 2 was identified in Capsicum genotype “Tobasco”, which was subsequently verified in a follow-up microplot trial using a range of initial population densities together with a susceptible Capsicum genotype “Paprika”. Reproduction factors of the nematodes were used as the main criterion to evaluate resistance. In the microplot trial, genotype “Tobasco” showed resistance at the lower inoculum levels but not at the higher nematode population levels. The need exists for more frequent and extensive screenings of the various vegetable genotypes in order to provide small-scale farmers with better options for improved and sustainable yields.  相似文献   

No detection of seed transmission of citrus tatter leaf virus in ‘Meyer’ lemon     

Cook  Glynnis  Steyn  Chanel  Breytenbach  Johannes H. J.  de Bruyn  Rochelle  Fourie  Paul H. 《植物病害和植物保护杂志》2020,127(6):895-898

Journal of Plant Diseases and Protection - Citrus tatter leaf virus (CTLV), a strain of apple stem grooving virus, is a virus of citrus that is of commercial importance for trifoliate orange...  相似文献   

Production of sterigmatocystin.     

M Steyn  C J Rabie 《Journal of the Association of Official Analytical Chemists》1975,58(3):622-623

A procedure for the isolation of pure sterigmatocystin is described. It involves cultivation of an appropriate fungus on sterile maize, and extraction and column chromatographic purification of the crude extract. With this method sterigmatocystin may be obtained at a fraction of its commercial cost. Aspergillus versicolor seemed to be the best producer (5-12 g/kg) in 250 ml Erlenmeyer flasks. The yield dropped markedly with increasing flask size.  相似文献