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Almost 19% of the GDP of Ethiopia results from livestock production. Ruminants, in particular, form the majority of the national herd and are a critical source of income for smallholder farmers. Infectious diseases have been identified as a major cause of reduced livestock productivity in low- and middle-income countries (LMICs); therefore, a sound and comprehensive understanding of the relevant evidence would be beneficial in order to enable decision making on disease control policies. However, livestock disease data from sub-Saharan Africa is variable and disparate, which poses a challenge for evidence synthesis. This paper describes a protocol for a systematic mapping review of the recent available evidence on ruminant disease prevalence and associated mortality in Ethiopia. Literature sources will be identified using database search strategies. The titles, abstracts and, subsequently, full texts will be screened for inclusion based on predefined eligibility criteria. Specific data will be extracted and a preliminary qualitative assessment of the evidence will be performed using predefined indicators. The planned systematic map will be the first to provide a large-scale overview of the available ruminant disease evidence in Ethiopia; the final output will be an interactive dashboard tool to inform critical stakeholders in policy and research.
The aim of this study was to examine the population structure, transmission and spatial relationship between genotypes of Shiga toxin-producing Escherichia coli (STEC) and Campylobacter jejuni, on 20 dairy farms in a defined catchment. Pooled faecal samples (n = 72) obtained from 288 calves were analysed by real-time polymerase chain reaction (rtPCR) for E. coli serotypes O26, O103, O111, O145 and O157. The number of samples positive for E. coli O26 (30/72) was high compared to E. coli O103 (7/72), O145 (3/72), O157 (2/72) and O111 (0/72). Eighteen E. coli O26 and 53 C. jejuni isolates were recovered from samples by bacterial culture. E. coli O26 and C. jejuni isolates were genotyped using pulsed-field gel electrophoresis and multilocus sequence typing, respectively. All E. coli O26 isolates could be divided into four clusters and the results indicated that E. coli O26 isolates recovered from calves on the same farm were more similar than isolates recovered from different farms in the catchment. There were 11 different sequence types of C. jejuni isolated from the cattle and 22 from water. An analysis of the population structure of C. jejuni isolated from cattle provided evidence of clustering of genotypes within farms, and among groups of farms separated by road boundaries.
The distribution of Near-Earth Objects, in particular Near-Earth asteroids is examined using maximum likelihood methods. These are analysed with respect magnitudes, taxonomic classes and to their orbital distances. Comparisons are made with the distributions of main-belt asteroids and short-period comets.
Causes of variation amongst cattle within a herd in their ability to initiate and maintain pregnancy are largely unknown. An experimental animal resource has recently been established to understand the biology of early reproductive performance. This paper summarises the results achieved during the establishment phase and from several experiments aimed at determining the physiological basis of the difference between sub-herds of contrasting pregnancy rates on Day 60. Each of 155 contemporary yearling heifers received 2 in vitro-produced embryos on 6 separate occasions during a 26-month period. Sixty days after transfer, pregnancy and twinning rates were determined ultrasonically, pregnancies terminated and the process repeated. The interval between successive transfers was greater than 100 days. Heifers were ranked on their aggregate pregnancy rate performance after 6 rounds of transfer, and the highest (High) and lowest (Low) 25 were retained. Differences in reproductive performance during the establishment phase of the herd are reported. In addition, several subsequent experiments examined ovarian follicle turnover and progesterone levels during an oestrous cycle, early embryo development after either AI or embryo transfer, and protein, interferon tau and ubiquitin-cross-reactive protein levels in uterine luminal flushings.Pregnancy rates were 7-folder higher in the High sub-herd (76 vs. 11%), with much of this difference apparent by Day 25. The proportion of heifers observed in standing oestrus prior to embryo transfer and the interval from the end of synchronisation treatment to the onset of oestrus were similar in the sub-herds. Oestrous cycle length, ovarian follicular dynamics and progesterone profiles during the oestrous cycle were also similar. More conceptuses had elongated by Day 14 in the High sub-herd (67 vs. 14%, P<0.05), which also tended to have a higher pregnancy rate after artificial insemination (52 vs. 29, P<0.1). Total protein in flushings from the uterus was similar in the sub-herds on Day 14 and Day 17. Conceptuses in the High sub-herd were longer on Day 17 following embryo transfer (6.5 vs. 4.8, P<0.05). Interferon-tau levels were higher in the High sub-herd (25.9 vs. 16.1, P<0.01), although ubiquitin cross-reactive protein levels were also higher in the High sub-herd, but this difference just failed to reach significance. We conclude that: 1. Most of the difference in sub-herd pregnancy rate occurs within 3 weeks of ET; 2. Ovarian factors are unlikely to contribute to the difference; 3. Major differences occur after blastocyst hatching and probably depend upon a differing endometrial environment before Day 14; 4. Differences in the ability of the uterine milieu to stimulate the expression of interferon-tau may be responsible for the differences in pregnancy rate; 5. The two sub-herds are a unique experimental resource for understanding early pregnancy in cattle following either AI or ET.
The reported post transfer survival rate to term of cloned embryos derived from both undifferentiated blastomeres and differentiated foetal and adult cells is very low (typically less than 20%). Furthermore, it is acknowledged that there are many technical issues that remain to be resolved to improve the efficiency of nuclear transfer before the technique will find widespread, practical and cost-effective use in multiplying valuable livestock in agriculture. The purpose of this study was to compare early embryo morphology following embryo transfer of nuclear transfer blastocysts derived from somatic cells of an adult Friesian cow with that of standard in vitro-produced embryos. In the present study, 150 embryos were transferred in bulk (i.e., 15, 20 or 25 per recipient) to the ipsilateral uterine horn of 8 recipients using standard non-surgical embryo transfer procedures. Embryos were then recovered following necropsy on either Day 14 or Day 23 of pregnancy and developmental traits described. Embryo recovery and elongation rates were similar on Day 14 of pregnancy (Table 1), although cloned conceptuses were longer and narrower (P<0.05). Embryo recovery and viability rates by Day 23 were similar, although many of the developmental traits appeared more advanced in cloned conceptuses. (Table 1). Allantois development was different because of greater widths and the presence of ‘spurs’ that were not observed with in vitro-produced embryos. We conclude that apparently abnormal conceptus development occurs by about 3 weeks of pregnancy following nuclear transfer, but that embryo survival is not compromised at this early stage of development.
Helical scanning is a means of producing computed tomography (CT) images by combining continuous rotation of the X-ray tube around the patient with a continuously moving couch to produce an integral volume of data. Siemens were the first to market a helical scanner in 1990, quickly followed by the other CT manufacturers, and now all scanners marketed have some level of helical capability. The terms ‘spiral’, ‘helical’ or ‘volume’ are synonymous as far as CT terminology is concerned and vary according to the manufacturer.
There are currently nearly 370 X-ray CT scanners in use in the UK; approximately one scanner per 160 000 of the population. All the CT scanners installed since 1995, and nearly 50% of the total number of scanners, have helical capability.
In 1989, when there were just 200 working scanners in the UK, the National Radiological Protection Board (NRPB) found that CT contributed to 20% of the radiation dose due to medical radiation in diagnostic practice in the UK, although it contributed only 2% of the imaging workload. As well as the above mentioned increase in the number of scanners, the introduction of slip-ring technology has improved the capabilities of X-ray CT scanners, and allowed greater patient throughput, a greater variety of scans, and more types of investigation. It would not be unrealistic therefore to expect that the proportion of the medical radiation dose due to CT has increased.
Progress has been made in understanding the stability of hierarchical three-body systems where the third body moves on an approximately Keplerian orbit about the centre of mass of the binary, at a distance large compared to the binary separation. Harrington (1968,1969) showed analytically that provided the third body was sufficiently distant from the binary no secular terms appeared in the semi-major axis and the system was stable. Harrington (1972,1975,1977) established numerically a critical minimum separation distance (or period) for a stable system in terms of the masses, unaffected by the relative inclinations of the orbits, except for angles close to 90°. Most subsequent investigations have therefore used planar configurations. Graziani & Black (1981), Black (1982) and Pendleton & Black (1983) again using long-term integration of the orbits obtained a criterion for high and low mass binaries. Donnison & Mikulskis (1992,1994,1995) carried out numerical integrations on prograde, retrogade, planetary and stellar triple systems and found for prograde systems very good quantitative agreement with the c2H method. Eggleton & Kieselva (1995) suggested a critical distance ratio approximation determined by the masses in the system. Systems with eccentric orbits are covered using the period ratio determined by Kepler’s third law.
A mutation of a gene (discovered in Festuca pratensis
and designated sid ) confers indefinite greenness on
senescing leaves. Via intergeneric hybrids with Lolium multiflorum
L. and Lolium perenne L., the mutant gene
has been introgressed into a range of Lolium backgrounds. Using
genomic in situ hybridization we have identified
segments carrying sidy
in recombinant chromosomes of Lolium–Festuca introgression
lines. We also used L.
perenne lines segregating 1[ratio ]1 for the staygreen
character to tag the gene with molecular markers. In two mapping
populations a total of 84 genotypes were screened with isoenzymes, RAPD
RFLP probes and AFLP
primer pairs. Over 180 polymorphic loci were identified, representing 10
linkage groups spanning 600 cM. Two
AFLP markers are linked to sid at 4·6 and 14·9 cM,
close enough to be usable for marker-assisted selection.
Introgression of sidy
into Lolium temulentum L. resulted in the production of
near-isogenic inbreeding lines
suitable for comparative studies of gene expression. Using a variation
method of representational difference
analysis a very small number of cDNAs have been identified as promising
candidates for sid, or genes directly
regulated by sid.
Kuiper(1973) suggested that the stability of the Solar System may be meaningfully investigated by studying the stability of the Sun-Jupiter-Saturn system. Numerical investigations by Nacozy(1976) showed that mass enhancement of the two planets beyond a factor of 29.25 led to instabilities in the system. In this new investigation similar mass enhancements were studied in detail numerically and compared with the analytical values derived from the c2H method. In addition, the eccentricities of the two planets were varied as well as their masses. It was found that the system soon showed signs of instability for the increased eccentricities when the masses of the planets were enhanced by fairly small factors.
This response to Stein Ringen's paper recognises the importance of his recent work and the validity of some of the criticisms he makes of poverty studies, but argues that his own approach suffers from some of the same defects. He dismisses this research too hastily, partly because he has neglected some of the best of it. Drawing on these sources, this paper formulates with their help a more rigorous presentation of the relative concept of poverty and the analytical steps which should be taken by those using this concept.