Taxonomy, phylogeny and biogeography of cisticolas (Cisticola spp.)

A review of the genus Cisticola was published in 1930 by Rear-admiral Lynes. While subsequent authors have modified Lynes' original groupings, his work remains the basis for modern syntheses of cisticolas. This study tests Lynes' hypotheses by analysing data that he presented in his review and with measurement and plumage data collected from museum specimens. Lynes' groupings were well recovered (98%) when data captured from his review were analysed phenetically, suggesting that he grouped species mostly by similarity. In contrast, when morpho-behavioural data were analysed using cladistic methods, many of his groupings were not monophyletic and the resultant cladogram had very little nodal support due to their highly conservative morphology. To resolve the structure of the genus and the relationships within it, two mitochondrial and four nuclear regions were sequenced from toe-pad samples taken from museum specimens. The molecular analyses included 44 of the 49 currently recognised species and represents the most taxon-dense molecular phylogeny of the genus. The resultant phylogeny separates species into five main clades, but many of Lynes' groupings were not monophyletic and there was also very little support for more recent groupings. Vocalisation analyses indicated that frequency components of songs were correlated with habitat type and body size. These correlations, though, disappeared when phylogeny was controlled for indicating that phylogenetic history rather than habitat preference influenced song character distribution. Some song types are mismatched to their environment, and some sympatric sister species appear to give similar calls. Cisticolas may overcome these attenuation and identification difficulties with behavioural adaptations and aerial displays. The biogeographic distribution of closely related species does not agree with many of the previously proposed hypotheses and a dated phylogeny estimates that most of the diversification in the genus has occurred within the last five million years. Most of the mean divergence date estimates correlated with periods of climate variability and episodes during which there is evidence for high lake levels in Africa, rather than correlating with Plio-Pleistocene glaciation, offering evidence that open habitats may have become fragmented during extremes of both arid and humid climates

Migrant workers in the East Midlands labour market 2010

This report is an update of previous intelligence (Migrant Workers in the East Midlands Labour Market 2007) on the profile and economic impact of migrant labour in the East Midlands economy

Electronic structure and conductance of DNA

In this thesis an efficient method has been developed for calculating the electronic structure and conductance of large biological molecules. The embedding method has been adapted to allow the splitting of large molecules such as DNA into smaller component blocks, completely preserving the information of the macro-system. The computational time required for this method increases as O(N) with the size of the system, instead of the traditional O(N3). The semi-empirical extended Huckel theory is used to describe the electron wavefunctions within a tight-binding scheme, taking the effect of the metal-molecule contacts into account. Presented in this thesis are the results for several different DNA molecules and structures. It has been determined that the transmission through DNA depends sensitively on the energy at which it is evaluated, and the atoms to which the metallic leads are connected. It is also found that poly(G)-poly(C) DNA conducts charge better than DNA with mixed bases, and that energy-minimised DNA with less structural disorder conducts better than DNA obtained from x-ray diffraction experiments. The electrical conduction of DNA that has undergone stretching has been investigated, and the distorted structure gives very small currents. The embedding method has also been applied to the small aromatic molecule OPE, to determine its electronic properties. Metallic conductivity is found for this molecule, and it is able to carry currents 1000 times greater than DNA, giving possible applications in molecular electronics.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Structural analysis of the human SYCE2-TEX12 complex provides molecular insights into synaptonemal complex assembly

The successful completion of meiosis is essential for all sexually reproducing organisms. The synaptonemal complex (SC) is a large proteinaceous structure that holds together homologous chromosomes during meiosis, providing the structural framework for meiotic recombination and crossover formation. Errors in SC formation are associated with infertility, recurrent miscarriage and aneuploidy. The current lack of molecular information about the dynamic process of SC assembly severely restricts our understanding of its function in meiosis. Here, we provide the first biochemical and structural analysis of an SC protein component and propose a structural basis for its function in SC assembly. We show that human SC proteins SYCE2 and TEX12 form a highly stable, constitutive complex, and define the regions responsible for their homotypic and heterotypic interactions. Biophysical analysis reveals that the SYCE2–TEX12 complex is an equimolar hetero-octamer, formed from the association of an SYCE2 tetramer and two TEX12 dimers. Electron microscopy shows that biochemically reconstituted SYCE2–TEX12 complexes assemble spontaneously into filamentous structures that resemble the known physical features of the SC central element (CE). Our findings can be combined with existing biological data in a model of chromosome synapsis driven by growth of SYCE2–TEX12 higher-order structures within the CE of the SC

Review of the occupational health and safety of Britain’s ethnic minorities

This report sets out an evidence-based review on work-related health and safety issues relating to black and minority ethnic groups. Data included available statistical materials and a systematic review of published research and practice-based reports. UK South Asians are generally under-represented within the most hazardous occupational groups. They have lower accident rates overall, while Black Caribbean workers rates are similar to the general population; Bangladeshi and Chinese workers report lowest workplace injury rates UK South Asian people exhibit higher levels of limiting long-term illness (LLI) and self reported poor health than the general population while Black Africans and Chinese report lower levels. Ethnic minority workers with LLI are more likely than whites to withdraw from the workforce, or to experience lower wage rates. Some of these findings conflict with evidence of differentials from USA, Europe and Australasia, but there is a dearth of effective primary research or reliable monitoring data from UK sources. There remains a need to improve monitoring and data collection relating to black and ethnic minority populations and migrant workers. Suggestions are made relating to workshops on occupational health promotion programmes for ethnic minorities, and ethnic minority health and safety 'Beacon' sites

Electronic structure and conductance of DNA

In this thesis an efficient method has been developed for calculating the electronic structure and conductance of large biological molecules. The embedding method has been adapted to allow the splitting of large molecules such as DNA into smaller component blocks, completely preserving the information of the macro-system. The computational time required for this method increases as O(N) with the size of the system, instead of the traditional O(N3). The semi-empirical extended Huckel theory is used to describe the electron wavefunctions within a tight-binding scheme, taking the effect of the metal-molecule contacts into account. Presented in this thesis are the results for several different DNA molecules and structures. It has been determined that the transmission through DNA depends sensitively on the energy at which it is evaluated, and the atoms to which the metallic leads are connected. It is also found that poly(G)-poly(C) DNA conducts charge better than DNA with mixed bases, and that energy-minimised DNA with less structural disorder conducts better than DNA obtained from x-ray diffraction experiments. The electrical conduction of DNA that has undergone stretching has been investigated, and the distorted structure gives very small currents. The embedding method has also been applied to the small aromatic molecule OPE, to determine its electronic properties. Metallic conductivity is found for this molecule, and it is able to carry currents 1000 times greater than DNA, giving possible applications in molecular electronics

Age- and sex-based variation in helminth infection of helmeted guineafowl (Numida meleagris) with comments on Swainson's spurfowl (Pternistis swainsonii) and Orange River francolin (Scleroptila levaillantoides)

Gastrointestinal tracts from 48 helmeted guineafowl (Numida meleagris), five Swainson's spurfowl (Pternistis swainsonii) and a single Orange River francolin (Scleroptila levaillantoides) were examined for helminth parasites. Twelve species of helminths were found in helmeted guineafowl, comprising six nematodes, five cestodes and a single acanthocephalan. Six species of nematodes were recovered from Swainson's spurfowl and a single nematode was recovered from the Orange River francolin. First-year guineafowl had more than twice the intensity of infection than did adult guineafowl, particularly regarding the acanthocephalan Mediorhynchus gallinarum, the caecal nematodes Subulura dentigera and S. suctoria, and the cestodes Octopetalum numida, Hymenolepis cantaniana and Numidella numida. Female guineafowl had significantly higher intensities of infection than males, especially concerning M. gallinarum, S. dentigera and N. numida and the nematode Gongylonema congolense. The recovery of the cestode Retinometra sp. from helmeted guineafowl constitutes a new host-parasite record