Late quaternary palaeoclimatic reconstructions in Patagonia using chironomid analysis

This thesis investigates Late Quaternary palaeoclimate in Patagonia to increase our understanding of the nature and timing of climate change in the mid-latitude regions of the Southern Hemisphere. Palaeoenvironmental reconstructions are presented which date back to the Last Glacial Interglacial Transition (> c. 13.5 cal ka BP) from two lakes in Chilean Patagonia: Laguna Boal in the Chonos Archipelago (44° 39'S, 73° 39'W) and Laguna Leta in the Chilean Lake District (41° 33'S, 73° 10'W). The investigation focuses principally on the analysis of sub-fossil Chironomidae (Insecta: Diptera) to infer palaeoenvironmental conditions. Combined 14C dating and tephrochronology provide the chronological framework for the records. As ecological information about the modem Patagonian Chironomidae fauna is scarce, faunal assemblages at 78 lakes were analysed in conjunction with potentially controlling environmental variables in order to aid the ecological interpretation of sub-fossil assemblages.Analysis of the modem data raised taxonomic issues related to identification of sub-fossil larval specimens, highlighting the need for more Neotropical taxonomic studies. Multivariate analysis of relationships between the modern day fauna and environmental variables indicated that the relationships present were not strong enough to produce a transfer function for the region. The environmental factors that varied most with the taxonomic assemblages were the organic content of substrate, lake depth, altitude, latitude and longitude. Water temperature, which has previously been demonstrated to have a strong effect on Chironomidae distribution, was not significantly correlated with the Patagonian faunal assemblages. These results indicate that the fauna encountered in this study may be more eurytopic than that studied in previous Holarctic investigations. Although the strength of environmental - taxonomic relationships was insufficient to warrant production of a transfer function, the investigation allowed qualitative interpretations of the down-core record to be made in conjunction with previously published data on Holarctic midge ecology.The records from Laguna Leta and Laguna Boal both indicate that climate oscillated during the transition from glacial to interglacial conditions, as fluctuations in lake depths are suggested by changes in both the chironomid assemblages and sediment properties. Results are generally equivocal in terms of determining whether such changes were precipitation or temperature driven. Nonetheless, such inferred changes add valuable evidence to the assertion that climatic instability prevailed throughout this time period in Patagonia - an argument that has been refuted by previous palynological work. Climatic interpretation of the Laguna Boal Holocene record is somewhat equivocal, but indicates that local, basin specific changes may have determined the assemblage versus palaeoclimatic controls. However, at a Laguna Leta a drop in lake levels during the early Holocene may have been followed by a notable rise in water level at c. 7.8 cal yr BP. This latter record supports previous palynological work in the region indicative of a concomitant rise in effective precipitation. The results of this pioneering study suggest that the use of chironomid analysis as a palaeoclimatic technique for this area is promising, but that more information on the midges' modern distribution in Patagonia is required to improve its application in future studies

The Evolution of the Concept of Sleep and Movement Behaviour to the UK High Performance Sport Industry

The UK high performance industry has evolved and expanded over the last 20 years. Parallel to this has been an upsurge in the Sports Science industry with contemporary practitioners providing more support to elite athletes in a much more comprehensive and scientific manner. 'What it Takes to Win' (WITTW) models now form a strategic part of the performance planning process and many factors impact on WITTW variables. Fatigue management, through assessment of sleep and also, associated daytime movement behaviour, is an example of such a factor. I collectively term the assessment of both these variables 'Fatigue Management'. Limited knowledge exists regarding sleep characteristics and movement behaviour of elite athletes. Therefore, I present in this thesis the evolution of the concept of fatigue management practices (through athlete sleep and associated movement behaviour assessment), and show how it has been included in the routine methods of Sports Science and Medicine practitioners. Whilst sleep remains a poorly understood entity there is evidence of a reciprocal relationship between sleep and athletic performance with disturbed sleep having a detrimental effect on psycho-physiological processes. In the absence of an effective fatigue management strategy this can be particularly problematic for elite athletes. A technical description of sleep and associated movement behaviour are presented along with methodologies for fatigue management assessment and details of projects using fatigue management strategies. To add context and insight, subjective findings of the impact of introducing this new concept within UK high performance sports' programmes are presented. I present that physiologists should assess fatigue management in the elite athletes they support and use this assessment for dialogue with coaches and sports science and medicine peers, to ensure provision of optimal fatigue management strategies in the performance programmes with which they work. Finally, success factors, methods of optimal practice and future recommendations for an effective fatigue management strategy are presented

Does elite sport degrade sleep quality? A systematic review

Background: Information on sleep quality and insomnia symptomatology among elite athletes remains poorly systematised in the sports science and medicine literature. The extent to which performance in elite sport represents a risk for chronic insomnia is unknown. Objectives: The purpose of this systematic review was to profile the objective and experienced characteristics of sleep among elite athletes, and to consider relationships between elite sport and insomnia symptomatology. Methods: Studies relating to sleep involving participants described on a pre-defined continuum of ‘eliteness’ were located through a systematic search of four research databases: SPORTDiscus, PubMed, Science Direct and Google Scholar, up to April 2016. Once extracted, studies were categorised as (1) those mainly describing sleep structure/patterns, (2) those mainly describing sleep quality and insomnia symptomatology and (3) those exploring associations between aspects of elite sport and sleep outcomes. Results: The search returned 1676 records. Following screening against set criteria, a total of 37 studies were identified. The quality of evidence reviewed was generally low. Pooled sleep quality data revealed high levels of sleep complaints in elite athletes. Three risk factors for sleep disturbance were broadly identified: (1) training, (2) travel and (3) competition. Conclusion: While acknowledging the limited number of high-quality evidence reviewed, athletes show a high overall prevalence of insomnia symptoms characterised by longer sleep latencies, greater sleep fragmentation, non-restorative sleep, and excessive daytime fatigue. These symptoms show marked inter-sport differences. Two underlying mechanisms are implicated in the mediation of sport-related insomnia symptoms: pre-sleep cognitive arousal and sleep restriction

Multiple achromatic plumage ornaments signal to multiple receivers

We investigated whether achromatic plumage traits can act as multiple ornaments in an Arctic-breeding passerine, the snow bunting (Plectrophenax nivalis). Specifically, we examine whether multiple ornaments are providing multiple differing messages, are redundant, are unreliable signals of male quality, or are aimed at different receivers. We measured plumage reflectance and pigmentation patterns made conspicuous during male inter-and intrasexual displays that advertise different plumage regions. Our results indicate that although several aspects of male plumage may have redundant messages, different body regions appear aimed at different receivers. The wings of males-displayed primarily toward females during courtship-appear to indicate a pair\u27s future reproductive performance. Conversely, melanin-based plumage reflectance displayed during intrasexual threat displays provides information on territory features and a male\u27s capacity to defend it (i.e., territory size, territory quality, testosterone levels). Taken together, we suggest that snow buntings have multiple ornaments that provide information of differential importance in inter-versus intrasexual communication. This study demonstrates that achromatic plumage traits can serve in complex communication. © 2012 The Author

Lineage dynamics of murine pancreatic development at single-cell resolution.

Organogenesis requires the complex interactions of multiple cell lineages that coordinate their expansion, differentiation, and maturation over time. Here, we profile the cell types within the epithelial and mesenchymal compartments of the murine pancreas across developmental time using a combination of single-cell RNA sequencing, immunofluorescence, in situ hybridization, and genetic lineage tracing. We identify previously underappreciated cellular heterogeneity of the developing mesenchyme and reconstruct potential lineage relationships among the pancreatic mesothelium and mesenchymal cell types. Within the epithelium, we find a previously undescribed endocrine progenitor population, as well as an analogous population in both human fetal tissue and human embryonic stem cells differentiating toward a pancreatic beta cell fate. Further, we identify candidate transcriptional regulators along the differentiation trajectory of this population toward the alpha or beta cell lineages. This work establishes a roadmap of pancreatic development and demonstrates the broad utility of this approach for understanding lineage dynamics in developing organs

Relation Between Age and Unplanned Readmissions After Percutaneous Coronary Intervention (Findings from the Nationwide Readmission Database))

Acknowledgements: We are grateful to the Healthcare Cost and Utilization Project (HCUP) and the HCUP Data Partners for providing the data used in the analysis. List of Supports/Grants Information: The study was supported by a grant from the Research and Development Department at the Royal Stoke Hospital. This work is conducted as a part of PhD for CSK which is supported by Biosensors International.Peer reviewedPostprin

Development of the Malocclusion Impact Questionnaire (MIQ) to measure the oral health-related quality of life of young people with malocclusion: part 2 - cross-sectional validation.

OBJECTIVE: To test the items, identified through qualitative inquiry that might form the basis of a new Malocclusion Impact Questionnaire (MIQ) to measure the oral health-related quality of life (OHQoL) of young people with malocclusion. METHODS: Piloting with 13 young people reduced the number of items from 37 to 28. Cross-sectional testing involved a convenience sample aged 10-16 years, attending the Orthodontic Department of the Charles Clifford Dental Hospital, Sheffield. The fit and function of the initial MIQ questions were examined using item response theory. RESULTS: 184 participants (113 females; 71 males) completed a questionnaire (response 85%), seven participants were excluded due to missing responses. The mean age of participants was 12·9 years (SD 1·4) and they had a wide range of malocclusions. The majority were White British (67·4%). Data from 47 participants were used to analyse test-retest reliability. Rasch analysis was undertaken, which further reduced the number of items in the questionnaire from 28 to 17. Unidimensionality of the scale was confirmed. The analysis also identified that the original 5-point response scale could be reduced to three points. The new measure demonstrated good criterion validity (r = 0·751; P < 0·001) and construct validity with the two global questions ('Overall bother' ρ = 0·733 and 'Life overall' ρ = 0·701). Internal consistency (Cronbach's alpha = 0·906) and test-retest reliability Intraclass correlation coefficient (ICC = 0·78; 95% CI 0·61-0·88) were also good. CONCLUSION: Cross-sectional testing has shown the new MIQ to be both valid and reliable. Further evaluation is required to confirm the generalisability as well as the ability of the new measure to detect change over time (responsiveness)

Reproductive control via eviction (but not the threat of eviction) in banded mongooses

Considerable research has focused on understanding variation in reproductive skew in cooperative animal societies, but the pace of theoretical development has far outstripped empirical testing of the models. One major class of model suggests that dominant individuals can use the threat of eviction to deter subordinate reproduction (the ‘restraint’ model), but this idea remains untested. Here, we use long-term behavioural and genetic data to test the assumptions of the restraint model in banded mongooses (Mungos mungo), a species in which subordinates breed regularly and evictions are common. We found that dominant females suffer reproductive costs when subordinates breed, and respond to these costs by evicting breeding subordinates from the group en masse, in agreement with the assumptions of the model. We found no evidence, however, that subordinate females exercise reproductive restraint to avoid being evicted in the first place. This means that the pattern of reproduction is not the result of a reproductive ‘transaction’ to avert the threat of eviction. We present a simple game theoretical analysis that suggests that eviction threats may often be ineffective to induce pre-emptive restraint among multiple subordinates and predicts that threats of eviction (or departure) will be much more effective in dyadic relationships and linear hierarchies. Transactional models may be more applicable to these systems. Greater focus on testing the assumptions rather than predictions of skew models can lead to a better understanding of how animals control each other's reproduction, and the extent to which behaviour is shaped by overt acts versus hidden threats