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The link between solenoidal turbulence and slow star formation in G0.253+0.016
No full textStar formation in the Galactic disc is primarily controlled by gravity, turbulence, and magnetic fields. It is not clear that this also applies to star formation near the Galactic Centre. Here we determine the turbulence and star formation in the CMZ cloud G0.253+0.016. Using maps of 3mm dust emission and HNCO intensity-weighted velocity obtained with ALMA, we measure the volume-density variance and turbulent Mach number . Combining these with turbulence simulations to constrain the plasma , we reconstruct the turbulence driving parameter in G0.253+0.016. This low value of indicates solenoidal (divergence-free) driving of the turbulence in G0.253+0.016. By contrast, typical clouds in the Milky Way disc and spiral arms have a significant compressive (curl-free) driving component (). We speculate that shear causes the solenoidal driving in G0.253+0.016 and show that this may reduce the star formation rate by a factor of 7 compared to nearby clouds
An analysis of the physical demands of international female soccer match-play and the physical characteristics of elite players
No full textThe purpose of the thesis was to provide a detailed analysis of the physical demands of competitive international female soccer match-play and the physical characteristics of elite players. To date, the majority of research has focussed on sub-elite players with a lack of information available on international level competitors. The aim of the first study (Chapter 4) was to analyse match physical performance using a computerised tracking system (Prozone Sports Ltd., Leeds, England). A total of 167 individual match observations from 122 players competing in competitive international matches during the 2011-2012 and 2012-2013 seasons were completed. Total distance and total high-speed running distances (>14.4 km.h-1) were influenced by outfield playing position, with central midfielders completing the highest (10985 ± 706 m and 2882 ± 500 m) and central defenders (9489 ± 562 m and 1901 ± 268 m) the lowest distances, respectively. Greater total very high-speed running distances (>19.8 km.h-1) were completed when a team was without (399 ± 143 m) compared to with (313 ± 210 m) possession of the ball. The majority of sprints (>25.1 km.h-1) were over short distances with 95 % being less than 10 m. This study provides novel findings regarding the physical demands of different playing positions in competitive international female match-play and important insights for physical coaches preparing elite female players for competition. The aim of the second study (Chapter 5) was to determine the incidence and nature of repeated sprint and high-speed activity in match-play. Repeated sprint activity (a minimum of two efforts (>25.1 km.h-1) with 20 s or less recovery between efforts) was found to be rare during international female match-play with 1.1 ± 1.1 bouts per match. Repeated high-speed activity (a minimum of two efforts (>19.8 km.h-1) was influenced by playing position; with attacking-based players completing more bouts (37-40 bouts per match) than defensive players (22-33 bouts per match). Repeated sprint and high-speed bouts frequently comprised two efforts per bout, with a maximum of three and six efforts respectively. Collectively, this study provides physical coaches with useful data for replicating the demands of repeated high-speed activity and an understanding of the positional demands in order to aid the specificity of training. The aim of the third study (Chapter 6) was to attempt to apply a suitable approach for determining speed zones and to evaluate the application of specific zones to influence data outcome. Maximum match-play running speed in elite females was measured using Global Positioning System technology (STATSports, Viper, Ireland) in 230 individual match observations of 67 outfield players, during 19 international matches from 2011-2015. Female-specific speed zones and activity classifications were scaled appropriately to maximum match-play running speed. The resultant female-specific speed zones were on average 12.5 % lower than the standardised male zones, which if applied to the data in Chapter 4 would result in a small increases in total high-speed running (25 % to 28 %) and total very high-speed running (8 % to 9 %) relative to total distance. The calculated female-specific sprinting threshold (>22.0 km.h-1) corresponds to 82 % of the average maximum female match-play running speed presently observed and consequently might be more representative than the standardised male sprinting threshold (>25.1 km.h-1). However, as it was not possible to validate activity classifications in the current study it is suggested that the standardised thresholds should continue to be used to permit between playing position and gender comparisons, however, the activity classifications (e.g. walking, jogging, sprinting etc.) should be removed and replaced with the actual velocities. The aim of the fourth study (Chapter 7) was to examine the reliability of both anthropometric and performance measures in elite female soccer players. The data suggest that both junior and senior elite female players are able to adequately reproduce a variety of anthropometric (coefficient of variation = 0.1-1.3 %) and performance (coefficient of variation = 0.6-7.7 %) related tests and that reliable measures can be obtained using the present protocols and one familiarisation session. The sample size estimations (n<20) provided important insights for the participant recruitment in Chapter 8 and also suggest that the anthropometric and performance assessments are suitable for the longitudinal tracking of the fitness status of elite female players. The aim of the fifth study (Chapter 8) was to examine the physical characteristics of elite players, which were assessed in 471 national team players from 2011-2015. Anthropometric and performance variables improved with age; with large differences observed between U15s and seniors for body mass (53.9 ± 7.8 v 62.5 ± 5.8 kg), 30 m linear speed (4.78 ± 0.22 v 4.52 ± 0.17 s), countermovement jump (28.3 ± 4.0 cm v 33.4 ± 4.0 cm) and Yo Yo Intermittent Recovery Test Level 1 (1101 ± 369 m v 1583 ± 416 m). Similarities were observed for anthropometric and performance variables between the younger (U15 and U17) and older (U19 and senior) age groups. Goalkeepers generally exhibited inferior anthropometric and performance capabilities to outfield players. Faster linear speed times over short distances observed were in attackers (1.047 s v 1.061-1.077 s), greater repeated speed performance in wide midfielders and attackers (4.89-4.91 s v 4.92-4.99 s) and improved intermittent endurance performance in wide defenders (1483 m v 1260-1336 m) compared to other outfield playing positions. The normative physical characteristics presented, provide unique data for professionals involved in player recruitment and talent identification, whilst the positional differences in performance characteristics, coupled with an in-depth understanding of the demands of match-play can be applied to ensure training specificity. Collectively, the present data provides the most in-depth description of the physical demands and physical characteristics of elite female soccer players to date. The data describing the demands of match-play provides valuable insights for physical coaches preparing elite female players for competition, whilst the normative physical characteristic data provides important information to professionals involved in player recruitment and talent identification and those responsible for physical development
How effortful is cognitive control? Insights from a novel method measuring single-trial evoked beta-adrenergic cardiac reactivity
No full textThe ability to adjust attentional focus to varying levels of task demands depends on the adaptive recruitment of cognitive control processes. The present study investigated for the first time whether the mobilization of cognitive control during response-conflict trials in a flanker task is associated with effort-related sympathetic activity as measured by changes in the RZinterval at a single-trial level, thus providing an alternative to the pre-ejection period (PEP) which can only be reliably measured in ensemble-averaged data. We predicted that response conflict leads to a physiological orienting response (i.e. heart rate slowing) and increases in effort as reflected by changes in myocardial beta-adrenergic activity (i.e. decreased RZ interval). Our results indeed showed that response conflict led to cardiac deceleration and decreased RZ interval. However, the temporal overlap of the observed heart rate and RZ interval changes suggests that the effect on the latter reflects a change in cardiac pre-load (Frank-Starling mechanism). Our study was thus unable to provide evidence for the expected link between cognitive control and cardiovascular effort. However, it demonstrated that our single-trial analysis enables the assessment of transient changes in cardiac sympathetic activity, thus providing a promising tool for future studies that aim to investigate effort at a single-trial level
Symmetry lasts longer than random, but only for brief presentations.
No full textPrevious research has shown that explicit emotional content or physical image properties (e.g. luminance, size and numerosity) alter subjective duration. Palumbo et al. (2015) recently demonstrated that the presence or absence of abstract reflectional symmetry also influenced subjective duration. Here, we explored this phenomenon further by varying the type of symmetry (reflection or rotation) and the objective duration of stimulus presentation (less or more than one second). Experiment 1 used a verbal estimation task in which participants estimated the presentation duration of reflection, rotation symmetry or random square-field patterns. Longer estimates were given for reflectional symmetry images than rotation or random, but only when the image was presented for less than 1 second. There was no difference between rotation and random. These findings were confirmed by a second Experiment using a paired-comparison task. This temporal distortion could be because reflection has positive valence or because it is processed efficiently be the visual system. The mechanism remains to be determined. We are relatively sure, however, that reflectional patterns can increase subjective duration in the absence of explicit semantic content, and in the absence of changes in the size, luminance or numerosity in the images
Twenty-four-hour ambulatory blood pressure and heart rate profiles in diagnosing orthostatic hypotension in Parkinson's disease and multiple system atrophy.
No full textBACKGROUND AND PURPOSE: Twenty-four-hour ambulatory blood pressure and heart rate monitoring (24-h ABPM) can provide vital information on circadian blood pressure (BP) profiles, which are commonly abnormal in Parkinson's disease with and without autonomic failure (PD + AF and PD) and multiple system atrophy (MSA). Twenty-four-hour ABPM has not been directly compared between these disorders regarding cardiovascular autonomic function. Our aim was to determine the usefulness of 24-h ABPM with diary compared to head-up tilting (HUT) in diagnosing orthostatic hypotension (OH) in these patients. METHODS: Seventy-four patients (23 MSA, 18 PD + AF, 33 PD) underwent cardiovascular autonomic screening followed by 24-h ABPM with diary. Standing tests were included during 24-h ABPM. The sensitivity and specificity in detecting OH from the 24-h ABPM standing test were compared with HUT. RESULTS: There was no difference in OH during HUT between MSA and PD + AF (P > 0.05). There was a higher proportion of abnormal BP circadian rhythms in MSA and PD + AF compared to PD (P 0.05). Patients were divided into groups with OH (OH+) and without OH (OH-) on HUT. Using the standing test during 24-h ABPM, a systolic BP fall of >20 mmHg showed a sensitivity and specificity of 82% and 100% (area under the curve 0.91, 95% confidence interval 0.84-0.98) in differentiating OH+ from OH-. CONCLUSIONS: Parkinson's disease with autonomic failure and MSA patients had similar circadian BP patterns suggesting that autonomic dysfunction influences abnormal BP circadian patterns similarly in these disorders. The higher sensitivity and specificity in detecting OH using a systolic BP fall of >20 mmHg compared to a diastolic BP fall of >10 mmHg during the standing test supports its usefulness to assess autonomic function in MSA and PD
Practice conditions leading to the acquisition of perceptual-cognitive-motor processing
No full textIn this thesis, specific practice conditions were examined for skill acquisition and transfer of perceptual-cognitive-motor processes underlying dynamic and complex performance. The availability of visual and cognitive processes during practice was modulated to examine contribution of each process to the skill acquisition using a novel computer-based task where participants were required to select and execute decisions to move a cursor to a target whilst avoiding random moving objects. Results demonstrated that practice with necessary information and processes improved the task performance, whereas limiting the underlying processes attenuated skill acquisition. Subsequently, the underlying processes were examined by measuring eye movements and condition-action pairs. Successful skill acquisition was underpinned by the modified visual search and decision making processes through practice. However, limiting necessary sensory information and decoupling cognitive processing during practice developed specific sensorimotor behaviour that did not lead to successful task performance. These results provided an insight of the skill acquisition by suggesting that when a task requires the acquisition of perceptual-cognitive-motor processes to be successful, integration of these processes would be necessary, whereas decoupling of these processes would limit skill acquisition. Moreover, transfer of acquired processes was examined between two tasks. Both tasks required the acquisition of similar perceptual-cognitive processes in order to select successful cursor trajectories, but the main goal differed between tasks. In addition, for both tasks a yoked condition aimed to limit cognitive processes to investigate the role of transfer-appropriate processing in skill acquisition. Results showed positive transfer indicating that practice on another task improved performance on the other task, whereas limiting cognitive processes attenuated the skill acquisition and transfer. Transfer would be maximised when the underlying processes between practice and transfer domain are similar or matched, whereas the transfer would be attenuated when the necessary processes are decoupled during practice. The overall findings extend the research in perceptual-cognitive-motor processes and have several theoretical and applied implications
THE COMMUNICATING VILLAGE: HUMPHREY JENNINGS AND SURREALISM
No full textThis thesis examines the films of Humphrey Jennings, exploring his work in relation to surrealism. This examination provides an overview of how surrealism’s set of ideas is manifest in Jennings’s documentary film work. The thesis does not assert that his films are surrealist texts or that there is such a thing as a surrealist film; rather it explores how his films, produced in Britain in the period from 1936 to 1950, have a dialectical relationship with surrealism.The thesis first considers Jennings’s work in relation to documentary theory, outlining how and why he is considered a significant filmmaker in the documentary field. It then goes on to consider Jennings’s engagement with surrealism in Britain in the years prior to World War Two. The thesis identifies three paradoxes relating to surrealism in Britain, using these to explore surrealism as an aura that can be read in the films of Jennings.The thesis explores three active phases of Jennings’s film work, each phase culminating in a key film. It acknowledges that Spare Time (1939) and Listen to Britain (1942) are key films in Jennings’s oeuvre, examining these two films and then emphasising the importance of a third, previously generally overlooked, film, The Silent Village (1943). These explorations allow an examination of the way that Jennings’s films articulate the relationship between surrealism and the everyday, the sublime and the uncanny. The thesis asserts that there is a specifically British form of surrealism that has developed from the historical situation of Britain in the period from 1936 to 1946, one that draws from the national identity of Britain. The symbolic domain of British surrealism and its praxis can read in the films of Jennings and the auratic traces of Jennings’s films thread through the work of subsequent filmmakers. This thesis describes these traces as the communicating village. The thesis’s consideration of Jennings’s films in relation to surrealism offers a means by which to examine the work of subsequent filmmakers and to assess the importance of surrealism to British cinema
Identification and characterisation of a novel, multi-potent, skeletal muscle-derived stem cell with broad developmental plasticity
No full textPW1+/Pax7– skeletal muscle-derived interstitial progenitor cells (PICs) are myogenic in vitro, efficiently contribute to skeletal muscle regeneration in vivo, and are self-renewing in vivo whilst also giving rise to satellite cells (Mitchell et al. 2010). They have previously been identified in the mouse and pig and are bi-potent forming both smooth and skeletal muscle (Mitchell et al. 2010, Lewis et al. 2014). This study characterised murine PICs for stem cell properties of self-renewal, clonogenicity and multipotency. Furthermore, PW1 expression was assessed in cardiac tissue, and in an isolated Sca1+ cardiac stem cell population.
Satellite cells and PICs were identified and quantified in hind limb skeletal muscle of 3, 10 and 21 day, and 2 year old mice: there was a decline in abundance of both SC and PICs with age. PICs were isolated by MACS technology from hind limb murine skeletal muscle of 21 day old mice, and their phenotype characterised. Isolated PICs expressed markers of pluripotency; Oct3/4, Sox2 and Nanog, were clonogenic and self- renewing over >60 population doublings in vitro, with a population doubling time of 15.8±2.9 hours. Furthermore, PICs demonstrated multipotency both in vitro and in vivo giving rise to cell types from the 3 germ layers.
PW1+ cells were identified and quantified with respect to location in the heart on 3, 10 day, 21 day and 2 year old mice with the majority of cells found within the epicardium. There was rapid decline in abundance during postnatal development. CD45-/Sca-1+ CSCs were isolated from 6 week old mice via MACS technology and assessed for PW1 expression (83%).
In summary, this study showed PICs have broad developmental plasticity both in vitro and in vivo, and can be propagated and maintained in a primitive state in culture. Furthermore, PW1 also marks a stem cell population within the heart. These data opens new avenues for solid tissue engineering and regeneration utilising a single multi-potent stem cell type, isolated from an easily accessible source such as skeletal muscle
AN OBSERVATIONAL STUDY IN LIVERPOOL OF PREGNANT WOMEN WITH A BMI ≥ 35kg/m2 REGARDING DIETARY INTAKE, LIFESTYLE AND LIVED EXPERIENCE
Full text linkThe prevalence of maternal obesity is on the increase, compromising both maternal and foetal health. Previous intervention studies have been designed to limit the amount of gestational weight gain but in the absence of UK guidelines relating to optimum weight change in obese pregnancies and the negative experiences of obese women with regard to previous weight loss attempts it is reasonable to ask whether this is the most effective approach. It has been demonstrated that maternal dietary intake can impact on gestational weight gain and birth weight but there is little in the way of research into the impact that quality of diet has on outcomesAimsTo measure the quality of maternal dietary intake and weight change against pregnancy and birth outcomes and to explore and gain insight into the lived experience of obese pregnant women with a view to informing guidelines.MethodsPregnant women with a BMI≥35kg/m2 were recruited from antenatal clinic and asked to complete 3 day food diaries at 16,28 and 36 weeks gestation, The diaries were verified using a food atlas and analysed using Microdiet. A subset of women were then followed up and interviewed regarding their lived experience of obesity.ResultsThe women’s dietary intake deteriorated over the duration of pregnancy and there were significant associations between some micronutrients and pregnancy and birth outcomes. Women with a BMI 35-39.9kg/m2 were most likely to gain weight.ConclusionThe dietary intake of obese pregnant women is an important predictor of pregnancy and birth outcomes and it was demonstrated that the quality of diet significant deteriorated over the duration of pregnancy. Interventions designed to increase the quality of diet are urgently required
Determination of the far-infrared properties of galaxies in the Coma cluster
No full textThis thesis presents results from the deepest ever far-infrared study of the Coma cluster (Abell 1656), with the Herschel PACS and SPIRE instruments being used to observe the cluster at a wavelength range of 70-500 _m. These observations resulted in a catalogue consisting of 70 galaxies which were spectroscopically confirmed as Coma cluster members, from which far-infrared galaxy luminosity functions at 70, 100 and 160 _m were constructed. Additionally, the far-infrared properties of 68 of these galaxies were determined from spectral energy distribution fits across the full wavelength range. Finally, these galaxies were grouped by morphological type, resulting in 30 elliptical galaxies, 37 spiral galaxies and one with an unknown morphology. These results were then compared to other studies of both clusters and the field in order to ascertain the extent to which environmental processes affect galaxy evolution. A comparison of the luminosity functions at 100 and 160 _m and the equivalent functions from the Herschel Virgo cluster survey Auld et al. (2013) showed similarities in both the functional form and the function parameters describing them. A further comparison of the Coma cluster luminosity functions at all three PACS wavelengths and various field galaxy luminosity functions was made, and again the forms and function parameters were consistent to within the errors. This would imply that the environmental processes thought to occur within the clusters do not have as great an effect on the galaxy population as initially thought. The far-infrared properties derived from the spectral energy distribution fits were analysed by galaxy type. The early-types were found to have mean normalised dust masses, dust temperatures and total infrared luminosities of log10 _
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