The effects of the type A behaviour pattern, perceived stress and social structure on depressive symptomatology, alcohol consumption, and smoking behaviours : secondary analysis of an interaction model : a thesis presented in partial fulfilment of requirements for the degree of Master of Arts with endorsement in Clinical Psychology, Massey University

A theoretical interaction model is pre­sented relating perceived stress, the Type A Be­haviour Pattern (assessed by means of the Struc­tured Interview method), and the psychosocial var­iable close friends, with psychological and prob­lematic behavioural outcomes, The model was tested in a secondary analysis of data from a community sample of 524 New Zealand males ages between 30 and 55 years. (Spicer et al, 1981). As an adaption and elaboration of the original study model, stress variables included combined upset/excitement scores, upset alone, undesirable events, life events total, workload, loss upset, and bereavement upset, The latter two stress vari­ables were constructed out of the original data, Outcome variables included depressive symptomatol­ogy, alcohol consumption, and smoking behaviours, Consistent with findings in Spicer et al. (1981), interaction effects show Type As more likely to smoke and consume more alcohol than Type Bs, when under stress. Another significant finding is that number of close friends did not moderate the rela­tionship between the Type A Pattern and health outcomes, The Buffering Effect was therefore re­jected for this group, Overall, evidence showed the benefits of adopting an interaction strategy consequent upon the discovery of no main effect relationship among variables of interest. A notable few interactions were not in the expected direction, including the finding that Type As tended to drink more alcohol the more friends they had. Limitations of the present model focused on the relatively unsatisfactory performance of the workload and friends variables. Future studies of this type might well benefit from the inclusion of a qualitative component for each

The Bristol Hearth Tax 1662-1673

This is the proof version. The final version is available from Bristol Record Society via the link in this record Archived with permission of the Bristol Record SocietyBristol Record Society's publications vol. 7

Eye Movements during Auditory Attention Predict Individual Differences in Dorsal Attention Network Activity

The neural mechanisms supporting auditory attention are not fully understood. A dorsal frontoparietal network of brain regions is thought to mediate the spatial orienting of attention across all sensory modalities. Key parts of this network, the frontal eye fields (FEF) and the superior parietal lobes (SPL), contain retinotopic maps and elicit saccades when stimulated. This suggests that their recruitment during auditory attention might reflect crossmodal oculomotor processes; however this has not been confirmed experimentally. Here we investigate whether task-evoked eye movements during an auditory task can predict the magnitude of activity within the dorsal frontoparietal network. A spatial and non-spatial listening task was used with on-line eye-tracking and functional magnetic resonance imaging (fMRI). No visual stimuli or cues were used. The auditory task elicited systematic eye movements, with saccade rate and gaze position predicting attentional engagement and the cued sound location, respectively. Activity associated with these separate aspects of evoked eye-movements dissociated between the SPL and FEF. However these observed eye movements could not account for all the activation in the frontoparietal network. Our results suggest that the recruitment of the SPL and FEF during attentive listening reflects, at least partly, overt crossmodal oculomotor processes during non-visual attention. Further work is needed to establish whether the network’s remaining contribution to auditory attention is through covert crossmodal processes, or is directly involved in the manipulation of auditory information

Eye Movements during Auditory Attention Predict Individual Differences in Dorsal Attention Network Activity

The neural mechanisms supporting auditory attention are not fully understood. A dorsal frontoparietal network of brain regions is thought to mediate the spatial orienting of attention across all sensory modalities. Key parts of this network, the frontal eye fields (FEF) and the superior parietal lobes (SPL), contain retinotopic maps and elicit saccades when stimulated. This suggests that their recruitment during auditory attention might reflect crossmodal oculomotor processes; however this has not been confirmed experimentally. Here we investigate whether task-evoked eye movements during an auditory task can predict the magnitude of activity within the dorsal frontoparietal network. A spatial and non-spatial listening task was used with on-line eye-tracking and functional magnetic resonance imaging (fMRI). No visual stimuli or cues were used. The auditory task elicited systematic eye movements, with saccade rate and gaze position predicting attentional engagement and the cued sound location, respectively. Activity associated with these separate aspects of evoked eye-movements dissociated between the SPL and FEF. However these observed eye movements could not account for all the activation in the frontoparietal network. Our results suggest that the recruitment of the SPL and FEF during attentive listening reflects, at least partly, overt crossmodal oculomotor processes during non-visual attention. Further work is needed to establish whether the network’s remaining contribution to auditory attention is through covert crossmodal processes, or is directly involved in the manipulation of auditory information

Telomeric expression sites are highly conserved in trypanosoma brucei

Subtelomeric regions are often under-represented in genome sequences of eukaryotes. One of the best known examples of the use of telomere proximity for adaptive purposes are the bloodstream expression sites (BESs) of the African trypanosome Trypanosoma brucei. To enhance our understanding of BES structure and function in host adaptation and immune evasion, the BES repertoire from the Lister 427 strain of T. brucei were independently tagged and sequenced. BESs are polymorphic in size and structure but reveal a surprisingly conserved architecture in the context of extensive recombination. Very small BESs do exist and many functioning BESs do not contain the full complement of expression site associated genes (ESAGs). The consequences of duplicated or missing ESAGs, including ESAG9, a newly named ESAG12, and additional variant surface glycoprotein genes (VSGs) were evaluated by functional assays after BESs were tagged with a drug-resistance gene. Phylogenetic analysis of constituent ESAG families suggests that BESs are sequence mosaics and that extensive recombination has shaped the evolution of the BES repertoire. This work opens important perspectives in understanding the molecular mechanisms of antigenic variation, a widely used strategy for immune evasion in pathogens, and telomere biology

Antigenic Variation in Plasmodium falciparum Malaria Involves a Highly Structured Switching Pattern

Many pathogenic bacteria, fungi, and protozoa achieve chronic infection through an immune evasion strategy known as antigenic variation. In the human malaria parasite Plasmodium falciparum, this involves transcriptional switching among members of the var gene family, causing parasites with different antigenic and phenotypic characteristics to appear at different times within a population. Here we use a genome-wide approach to explore this process in vitro within a set of cloned parasite populations. Our analyses reveal a non-random, highly structured switch pathway where an initially dominant transcript switches via a set of switch-intermediates either to a new dominant transcript, or back to the original. We show that this specific pathway can arise through an evolutionary conflict in which the pathogen has to optimise between safeguarding its limited antigenic repertoire and remaining capable of establishing infections in non-naïve individuals. Our results thus demonstrate a crucial role for structured switching during the early phases of infections and provide a unifying theory of antigenic variation in P. falciparum malaria as a balanced process of parasite-intrinsic switching and immune-mediated selection

The effects of a partitioned var gene repertoire of Plasmodium falciparum on antigenic diversity and the acquisition of clinical immunity

<p>Abstract</p> <p>Background</p> <p>The human malaria parasite <it>Plasmodium falciparum </it>exploits antigenic diversity and within-host antigenic variation to evade the host's immune system. Of particular importance are the highly polymorphic <it>var </it>genes that encode the family of cell surface antigens PfEMP1 (<it>Plasmodium falciparum </it>Erythrocyte Membrane Protein 1). It has recently been shown that in spite of their extreme diversity, however, these genes fall into distinct groups according to chromosomal location or sequence similarity, and that recombination may be confined within these groups.</p> <p>Methods</p> <p>This study presents a mathematical analysis of how recombination hierarchies affect diversity, and, by using simple stochastic simulations, investigates how intra- and inter-genic diversity influence the rate at which individuals acquire clinical immunity.</p> <p>Results</p> <p>The analysis demonstrates that the partitioning of the <it>var </it>gene repertoire has a limiting effect on the total diversity attainable through recombination and that the limiting effect is strongly influenced by the respective sizes of each of the partitions. Furthermore, by associating expression of one of the groups with severe malaria it is demonstrated how a small number of infections can be sufficient to protect against disease despite a seemingly limitless number of possible non-identical repertoires.</p> <p>Conclusion</p> <p>Recombination hierarchies within the <it>var </it>gene repertoire of <it>P. falciparum </it>have a severe effect on strain diversity and the process of acquiring immunity against clinical malaria. Future studies will show how the existence of these recombining groups can offer an evolutionary advantage in spite of their restriction on diversity.</p