35 research outputs found
Virulence and heterologous strain immunity of South African and Australian Babesia bovis strains with reduced pathogenicity
A South African Babesia bovis strain showed loss of virulence after 10 rapid passages in splenectomized calves. The virulence was comparable with that of an attenuated Australian vaccine strain. Vaccination of crossbred Bos indicus cattle with the local strain resulted in a solid immunity to heterologous challenge. The degree of protection afforded by the Australian vaccine strain was adequate for controlling challenge with a virulent South African strain, but somewhat less than the degree conferred by the local vaccine strain. Serological observations with the indirect fluorescent antibody test confirmed a close relationship between the 2 modified strains.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
The MeerKAT Galaxy Cluster Legacy Survey: I. Survey overview and highlights
Please abstract in the article.The South African Radio Astronomy Observatory (SARAO), the National Research Foundation (NRF), the National Radio Astronomy Observatory, US National Science Foundation, the South African Research Chairs Initiative of the DSI/NRF, the SARAO HCD programme, the South African Research Chairs Initiative of the Department of Science and Innovation.http://www.aanda.orghj2022Physic
The SARAO MeerKAT 1.3Â GHz Galactic Plane Survey
We present the SARAO MeerKAT Galactic Plane Survey (SMGPS), a 1.3 GHz continuum survey of almost half of the Galactic Plane (251○ ≤l ≤ 358○ and 2○ ≤l ≤ 61○ at |b| ≤ 1
5). SMGPS is the largest, most sensitive and highest angular resolution 1 GHz survey of the Plane yet carried out, with an angular resolution of 8″ and a broadband RMS sensitivity of ∼10–20 μJy beam−1. Here we describe the first publicly available data release from SMGPS which comprises data cubes of frequency-resolved images over 908–1656 MHz, power law fits to the images, and broadband zeroth moment integrated intensity images. A thorough assessment of the data quality and guidance for future usage of the data products are given. Finally, we discuss the tremendous potential of SMGPS by showcasing highlights of the Galactic and extragalactic science that it permits. These highlights include the discovery of a new population of non-thermal radio filaments; identification of new candidate supernova remnants, pulsar wind nebulae and planetary nebulae; improved radio/mid-IR classification of rare Luminous Blue Variables and discovery of associated extended radio nebulae; new radio stars identified by Bayesian cross-matching techniques; the realisation that many of the largest radio-quiet WISE H II region candidates are not true H II regions; and a large sample of previously undiscovered background H I galaxies in the Zone of Avoidance
Phenotypic and genetic aspects of production in the Dohne Merino. III The influence of age of the ewe on reproductive performance
No Abstrac
Phenotypic and genetic aspects of production in the Dohne Merino. IV. The influence of age of the ewe on production lambs
To determine the influence of the age of the ewe on characteristics such as body mass, greasy fleece mass, clean fleece mass, fiber diameter and staple length the data obtained from 500 ewes born between 1970 and 1979 was used. Their body mass at mating increased from 55 kg to 61 kg between the ages of 1½ and 5½ years, after which it declined steeply to the age of 9½ years. Greasy fleece mass increased up to the age of 3½ years (4.53 kg) and then steadily declined up to the age of 9½ years (2.82 kg). In contrast, maximum clean fleece mass was achieved at the age of 1½ years (2.94 kg). Clean fleece mass declined by 17.5% from 1½ to 9½ years of age. Fiber diameter increased from 21.4 to 23.3 microns between the age of 1½ and 7½ years after which it declined up to the age of 9½ years. The staple length was 92.2 mm at 1½ years of age followed by a linear decline up to 9½ years of age
Reproductive performance of commercial Merino, Dohne Merino and SA Mutton Merino flocks in the Southern Cape
Data of 23 189 Merino ewes (8 farms), 7692 Dohne Merino ewes (3 farms) and 2399 SA Mutton Merino ewes (1 farm) were recorded for the 1988-1991 lambing seasons. The udders of ewes present at lamb marking were inspected to differentiate between barren (unlambed), lambed and lost (lambed ewes suckling no progeny), and wet (lambed and suckling ≥ 1 lamb) ewes, using the 'wet and dry' technique. The lambs present at lamb marking were counted, and information regarding number of ewes mated and managerial inputs was recorded. The mean number of lambs marked as a percentage of ewes joined (Lm/Ej) was 87.7% for Merino flocks, ranging between 62.8-103.3%. Figures for Dohne Merino flocks were found to be similar, ranging between 75.6-113.2% Lm/Ej, with a mean of 92.6%, while Lm/Ej was 112.7% in the SA Mutton Merino flock. Between 72.2% (Merino) and 80.4% (SA Mutton Merino) of joined ewes suckled ≥ 1 lamb at lamb marking. Mean fecundity (estimated number of lambs born as a percentage of ewes lambed) was estimated at 121.6% for Merino ewes, 122.7% for Dohne Merino ewes and 140.2% for SA Mutton Merino ewes. Significant (P ≤ 0.05) differences in Lm/Ej occurred between Merino and Dohne Merino ewes stocked on different farms. It was attempted to relate these differences to managerial practices (flock size at mating, mating period, percentage of rams, the use of vasectomized rams, the use of ultrasonic scanning, and management at lambing). Increasing flock sizes tended to be associated with a decline in Lm/Ej. Reproductive efficiency within flocks was independent of the other managerial practices. Ewes which failed to suckle ≥ 1 lamb to lamb marking during 1988 -1990 were ear notched (marked). The mean levels of reproductive failure in marked ewes (groups with < 40 marked ewes were excluded) were compared with those of contemporaries without a history of reproductive failure within lambing years and farms. In 15 groups of Merino ewes where this procedure was followed, the number of ewes dry (the total of the unlambed and lambed and lost categories) as a percentage of ewes present at lamb marking (Ed/Epm) was 33.7% compared to 24.2% for the 15 groups of contemporaries of these ewes (P ≤ 0.05). In four groups of Dohne Merino ewes, Ed/Epm was 32.8% for marked ewes and 21.5% for their contemporaries (P = 0.06). It was concluded that there was scope for the improvement of the reproductive efficiency of local woolled sheep flocks. Selection against reproductive failure by using the simple 'wet and dry' technique appears to be a low-input method for the improvement of reproductive performance in commercial sheep flocks, at least in the current flock. Results from the literature suggest that such selection will also benefit future generations.Data aangaande 23 189 Merino-ooie (8 plase), 7692 Dohne Merino-ooie (3 plase) en 2399 SA Vleismerino-ooie (1 plaas) is tydens die 1988-1991 lamseisoene aangeteken. Die uiers van ooie is by merk van lammers ondersoek om tussen onvrugbare (nie gelam), gelam en alle nageslag verloor (wel gelam, maar laat geen lammers suip nie) en produktiewe (gelam en laat suip ≥ 1 nageslag) ooie te onderskei, deur die eenvoudige 'soog en droog'-tegniek te gebruik. Die aantal lammers beskikbaar by merk is getel, en inligting oor aantal ooie gepaar en bestuursinsette is aangeteken. Die gemiddelde aantal lammers gemerk as 'n persentasie van ooie gepaar (Lm/Ej) was 87.7% vir Merinokuddes, met variasie tussen 62.8% en 103.3%. Ooreenstemmende syfers vir Dohne Merinokuddes het tussen 75.6 en 113.2% Lm/Ej gevarieer, met 'n gemiddelde van 92.6%, terwyl Lm/Ej vir die SA Vleismerinokudde 112.7% was. Tussen 72.2% (Merino) en 80.4% (SA Vleismerino) van gepaarde ooie het by merk ≥ 1 lam laat suip. Gemiddelde fekunditeit (beraamde aantal lammers gebore as persentasie van ooie gelam) is op 121.6% vir Merino's, 122.7% vir Dohne Merino's en 140.2% vir SA Vleismerino's beraam. Betekenisvolle (P ≤ 0.05) verskille in Lm/Ej het tussen Merino- en Dohne Merino-ooie op verskillende plase voorgekom. Daar is gepoog om dié verskille met bestuursinsette op verskillende plase (kuddegrootte by paar, lengte van paring, die persentasie ramme, die gebruik van koggelramme, die gebruik van ultraklankskandering en lambestuur) in verband te bring. 'n Toename in kuddegrootte het geneig om tot 'n afname in Lm/Ej te lei. Reproduksiedoeltreffendheid binne kuddes was onafhanklik van die ander bestuursinsette. Ooie wat geen lammers laat suip het gedurende 1988-1990 nie, is met oorknippe gemerk. Die gemiddelde peile van reproduksie-mislukking in gemerkte ooie (groepe met <40 gemerkte ooie is uitgesluit) is vergelyk met dié van tydgenote sonder 'n geskiedenis van reproduksieverliese binne jare en plase. In 15 groepe van Merino-ooie waar hierdie prosedure gevolg is, was die gemiddelde aantal 'ooie droog as persentasie van ooie teenwoordig by merk' (Ed/Epm) 33.7%, in vergelyking met 24.2% vir 15 groepe tydgenote van dié ooie (P ≤ 0.05). In vier groepe Dohne Merino-ooie in vergelyking met hul tydgenote was die ooreenstemmende syfers vir Ed/Epm onderskeidelik 32.8% en 21.5% (P = 0.06). Dit blyk dus dat daar ruimte vir die verdere verbetering van reproduksie in plaaslike wolskaapkuddes is. Seleksie teen reproduksie-mislukking deur gebruik te maak van die eenvoudige 'soog en droog'- tegniek blyk 'n lae-insetmetode vir die verbetering van reproduksie in kommersiële skaapkuddes te wees. Volgens resultate uit die literatuur sal sodanige seleksie ook toekomstige generasies bevoordeel.Keywords: Management, reapeted failure, reproductive performance, shee
The determination of earthworm species sensitivity differences to cadmium genotoxicity using the comet assay
The concept of species sensitivity differences is important in ecotoxicology and environmental risk assessment, but testing usually focuses on lethality of toxicants. The effects on the suborganismal level are mostly ignored; therefore, the present study assessed a biomarker of genotoxicity (the alkaline comet assay) to compare species sensitivities. Five earthworm species (Amynthas diffringens, Aporrectodea caliginosa, Dendrodrilus rubidus, Eisenia fetida and Microchaetus benhami) were exposed for 48 h to sublethal concentrations of cadmium sulphate in reconstituted soil water and DNA integrity was evaluated with the parameter Tail DNA %. Significant amounts of DNA damage were detected in three (A. caliginosa, D. rubidus and E. fetida) species. E. fetida exhibited the highest level of DNA damage, although D. rubidus showed the highest increase (3-fold) in DNA damage from the control. All exposed earthworms accumulated Cd, although body loads did not correspond with DNA damage levels; most of the Cd was probably sequestrated and rendered harmless. © 2006 Elsevier Inc. All rights reserved.Articl
Coagulant and fibrinolytic status in tuberculous meningitis
BACKGROUND: The long-term neurologic sequelae of childhood tuberculous meningitis (TBM) mainly result from ischemia owing to cerebral vasculitis. Deep vein thrombosis occurs in adults with pulmonary tuberculosis owing to hypercoaguability. The present study aimed to investigate coagulation status during acute childhood TBM. METHODS: Coagulation status, including the natural anticoagulants, antithrombin, protein C and protein S; procoagulant FVIII; fibrinolytic factors, tissue plasminogen activator and plasminogen activator inhibitor-1 (PAI-1) as well as anticardiolipin antibodies (ACA), was determined in 16 children with TBM before and during treatment. RESULTS: A prothrombotic profile was found as expressed by a decrease of anticoagulant (protein S) and increase of the procoagulant (factor VIII) activity. Raised PAI-1 and normal tissue plasminogen activator values indicated deficient fibrinolysis. This hypercoagulable state was more pronounced in stage 3 patients than in stage 2 patients. The bleeding time on admission ranged from 1.2 to 10 minutes [mean 4.2 minutes]. The mean platelet count on admission was 577.9 ± 188.6 × 10/L and increased further during the course of the treatment. CONCLUSIONS: The hypercoagulable state in childhood TBM is comparable to that described in adults with pulmonary tuberculosis and may further increase the risk for infarction. Therapeutic measures that reduce the risk for thrombosis could therefore be potentially beneficial in childhood TBM. © 2007 Lippincott Williams & Wilkins, Inc.Articl
Speciation and distribution of Botryosphaeria spp. on native and introduced Eucalyptus trees in Australia and South Africa
Botryosphaeria spp. are important canker and die-back pathogens that affect Eucalyptus spp. They also occur endophytically in Eucalyptus leaves and stems. For the purpose of this study, Botryosphaeria strains were isolated from diseased and symptomless Eucalyptus material from Australia and South Africa. These isolates were induced to sporulate in culture, and compared with known species of Botryosphaeria. Selected isolates were also compared with authentic isolates of known Botryosphaeria spp. based on nuclear DNA sequence data of the ITS rDNA, P-tubulin and elongation factor l-alpha regions. Five Botryosphaeria spp. were identified from Eucalyptus plants. The ITS rDNA sequence data were then used to develop a PCR RFLP technique that could distinguish these species. Botryosphaeria eucalyptorum and a new species, B. eucalypticola, were the most common species on Eucalyptus in eastern Australia. These species also occur on Eucalyptus in South Africa, where they have most likely been introduced. Botryosphaeria parva was common on Eucalyptus in exotic environments, but rare on this host in Australia. Although B. dothidea was previously thought to be common on eucalypts, only one isolate of each of B. dothidea and B. australis were found in all the areas surveyed. No isolates of B. ribis, which was also commonly reported from Eucalyptus, were identified during this survey from Eucalyptus. Data from the present study provide the first holistic overview of the species of Botryosphaeria associated with Eucalyptus in both native and exotic environments