The South Africa-Angola talks, 1976-1984: a little-known cold war thread

Published versionThat South Africa invaded Angola in 1975, in an abortive attempt to prevent a Marxist government coming to power there, and that the South African Defence Force then repeatedly attacked Angola from 1978, is relatively well known. That representatives of the South African and Angolan governments met on many occasions from 1976 is a largely untold story. This article uses documentation from the archives of the Department of International Relations and Cooperation, along with other sources, to analyse these talks and the Cold War context in which they took place.Department of HE and Training approved lis

Tracing the Origins of Refractory Inclusions - the Solar System's Oldest Solids: a Petrographic, Geochemical and 26Al-26Mg Dating Study of CV and CK Refractory Inclusions

Refractory inclusions in carbonaceous chondrite meteorites are of particular interest because both long- and short-lived chronometers have shown that they are the oldest sampled material to have formed in the Solar System. The objective of this study was to establish high-precision petrographic, chemical and isotopic analyses of refractory inclusions and thus offer insights into the chemical and astrophysical environments present during the formation of the Solar System. The former presence of the short-lived isotope 26Al (T1/2 = ca.730 KYr) has been established in a majority of refractory inclusions. Recent studies using both solution-based and in situ methodologies have suggested that the initial 26Al/27Al0 value of refractory inclusions is ca.6 x 10-5, higher than the established "canonical" value of [5.00 +/- 0.05] x 10-5. Knowing the initial concentration of 26Al within the Solar System provides a useful anchor from which ancient materials can be dated. Petrographic and trace element analyses were performed on nine newly-extracted refractory inclusions from CV3 and CK3 chondrites. These analyses revealed all but three refractory inclusions to have experienced multiple episodes of melting and evaporation prior to crystal closure. Mg isotope analyses were performed on eight of the newly extracted refractory inclusions in addition to five inter-laboratory samples. All refractory inclusions shown to have remained unaltered following crystal-closure, regardless of thermal history prior to closure, yielded a model 26Al/27Al0 of [4.89 x 0.265] x 10-5; within error of the canonical value. This result confirms that 26Al was homogenous and at canonical concentrations in the solar nebula. The results also suggest that chemical fractionation and crystal closure for the analysed refractory inclusions was completed within no more than 160 Kyr

Automated identification of Monogeneans using digital image processing and K-nearest neighbour approaches.

BACKGROUND: Monogeneans are flatworms (Platyhelminthes) that are primarily found on gills and skin of fishes. Monogenean parasites have attachment appendages at their haptoral regions that help them to move about the body surface and feed on skin and gill debris. Haptoral attachment organs consist of sclerotized hard parts such as hooks, anchors and marginal hooks. Monogenean species are differentiated based on their haptoral bars, anchors, marginal hooks, reproductive parts' (male and female copulatory organs) morphological characters and soft anatomical parts. The complex structure of these diagnostic organs and also their overlapping in microscopic digital images are impediments for developing fully automated identification system for monogeneans (LNCS 7666:256-263, 2012), (ISDA; 457-462, 2011), (J Zoolog Syst Evol Res 52(2): 95-99. 2013;). In this study images of hard parts of the haptoral organs such as bars and anchors are used to develop a fully automated identification technique for monogenean species identification by implementing image processing techniques and machine learning methods. RESULT: Images of four monogenean species namely Sinodiplectanotrema malayanus, Trianchoratus pahangensis, Metahaliotrema mizellei and Metahaliotrema sp. (undescribed) were used to develop an automated technique for identification. K-nearest neighbour (KNN) was applied to classify the monogenean specimens based on the extracted features. 50% of the dataset was used for training and the other 50% was used as testing for system evaluation. Our approach demonstrated overall classification accuracy of 90%. In this study Leave One Out (LOO) cross validation is used for validation of our system and the accuracy is 91.25%. CONCLUSIONS: The methods presented in this study facilitate fast and accurate fully automated classification of monogeneans at the species level. In future studies more classes will be included in the model, the time to capture the monogenean images will be reduced and improvements in extraction and selection of features will be implemented

Genomic Resources for Asparagales

Enormous genomic resources have been developed for plants in the monocot order Poales; however, it is not known how useful these resources will be for other economically important monocots. Asparagales are a monophyletic order sister to class Commelinanae that carries Poales, and is the second most economically important monocot order. Development of genomic resources for and their application to Asparagales are challenging because of huge nuclear genomes and the relatively long generation times required to develop segregating families. We synthesized a normalized eDNA library of onion (Allium cepa) and produced II ,008 unique expressed sequence tags (ESTs) for comparative genomic analyses of Asparagales and Poales. Alignments of onion ESTs, Poales ESTs, and genomic sequences from rice were used to design oligonucleotide primers amplifying genomic regions from asparagus, garlic, and onion. Sequence analyses of these genomic regions revealed microsatellites, insertions/deletions, and single nucleotide polymorphisms for comparative mapping of rice and Asparagales vegetables. Initial mapping revealed no obvious synteny at the recombinationallevel between onion and rice, indicating that genomic resources developed for Poales may not be applicable to the monocots as a whole. Genomic analyses of Asparagales would greatly benefit from EST sequencing and deep-coverage, large-insert genomic libraries of representative small-genome model species within the higher and lower Asparagales, such as asparagus and orchid, respectively

Highly syntenic regions in the genomes of soybean, Medicago truncatula, and Arabidopsis thaliana

BACKGROUND: Recent genome sequencing enables mega-base scale comparisons between related genomes. Comparisons between animals, plants, fungi, and bacteria demonstrate extensive synteny tempered by rearrangements. Within the legume plant family, glimpses of synteny have also been observed. Characterizing syntenic relationships in legumes is important in transferring knowledge from model legumes to crops that are important sources of protein, fixed nitrogen, and health-promoting compounds. RESULTS: We have uncovered two large soybean regions exhibiting synteny with M. truncatula and with a network of segmentally duplicated regions in Arabidopsis. In all, syntenic regions comprise over 500 predicted genes spanning 3 Mb. Up to 75% of soybean genes are colinear with M. truncatula, including one region in which 33 of 35 soybean predicted genes with database support are colinear to M. truncatula. In some regions, 60% of soybean genes share colinearity with a network of A. thaliana duplications. One region is especially interesting because this 500 kbp segment of soybean is syntenic to two paralogous regions in M. truncatula on different chromosomes. Phylogenetic analysis of individual genes within these regions demonstrates that one is orthologous to the soybean region, with which it also shows substantially denser synteny and significantly lower levels of synonymous nucleotide substitutions. The other M. truncatula region is inferred to be paralogous, presumably resulting from a duplication event preceding speciation. CONCLUSION: The presence of well-defined M. truncatula segments showing orthologous and paralogous relationships with soybean allows us to explore the evolution of contiguous genomic regions in the context of ancient genome duplication and speciation events

The complete chloroplast genome sequence of Gossypium hirsutum: organization and phylogenetic relationships to other angiosperms

BACKGROUND: Cotton (Gossypium hirsutum) is the most important fiber crop grown in 90 countries. In 2004–2005, US farmers planted 79% of the 5.7-million hectares of nuclear transgenic cotton. Unfortunately, genetically modified cotton has the potential to hybridize with other cultivated and wild relatives, resulting in geographical restrictions to cultivation. However, chloroplast genetic engineering offers the possibility of containment because of maternal inheritance of transgenes. The complete chloroplast genome of cotton provides essential information required for genetic engineering. In addition, the sequence data were used to assess phylogenetic relationships among the major clades of rosids using cotton and 25 other completely sequenced angiosperm chloroplast genomes. RESULTS: The complete cotton chloroplast genome is 160,301 bp in length, with 112 unique genes and 19 duplicated genes within the IR, containing a total of 131 genes. There are four ribosomal RNAs, 30 distinct tRNA genes and 17 intron-containing genes. The gene order in cotton is identical to that of tobacco but lacks rpl22 and infA. There are 30 direct and 24 inverted repeats 30 bp or longer with a sequence identity ≥ 90%. Most of the direct repeats are within intergenic spacer regions, introns and a 72 bp-long direct repeat is within the psaA and psaB genes. Comparison of protein coding sequences with expressed sequence tags (ESTs) revealed nucleotide substitutions resulting in amino acid changes in ndhC, rpl23, rpl20, rps3 and clpP. Phylogenetic analysis of a data set including 61 protein-coding genes using both maximum likelihood and maximum parsimony were performed for 28 taxa, including cotton and five other angiosperm chloroplast genomes that were not included in any previous phylogenies. CONCLUSION: Cotton chloroplast genome lacks rpl22 and infA and contains a number of dispersed direct and inverted repeats. RNA editing resulted in amino acid changes with significant impact on their hydropathy. Phylogenetic analysis provides strong support for the position of cotton in the Malvales in the eurosids II clade sister to Arabidopsis in the Brassicales. Furthermore, there is strong support for the placement of the Myrtales sister to the eurosid I clade, although expanded taxon sampling is needed to further test this relationship