Cronfa at Swansea University
Velocity map imaging of femtosecond laser induced photoelectron emission from metal nanotips
Get PDFA novel application of velocity-map imaging (VMI) is demonstrated, whereby the momentum distribution of photoelectrons ejected from a tungsten nanoscale metal tip (< 50 nm radius) is recorded following illumination with an ultrafast laser pulse. The electrostatic conditions in the VMI instrument are optimized through finite element modelling, taking into account a physically realistic geometry including all conductive elements in the vicinity of the electron trajectories. The instrument is calibrated by observing above threshold ionization in krypton gas, and simultaneous electron emission from this gas and a tungsten nanotip is presented, illustrating that the velocity mapping condition is maintained. Realizing photoelectron VMI for femtosecond laser illuminated nanoscale objects will have a significant impact on the emerging field of ultrafast nanoplasmonics and will influence the development of such devices as a source of coherent pulses of electrons with applications in time-resolved microscopy, holography and diffractive imaging
A Passive Heat Maintenance Strategy Implemented during a Simulated Half-Time Improves Lower Body Power Output and Repeated Sprint Ability in Professional Rugby Union Players
Get PDFReduced physical performance has been observed following the half-time period in team sports players, likely due to a decrease in muscle temperature during this period. We examined the effects of a passive heat maintenance strategy employed between successive exercise bouts on core temperature (Tcore) and subsequent exercise performance. Eighteen professional Rugby Union players completed this randomised and counter-balanced study. After a standardised warm-up (WU) and 15 min of rest, players completed a repeated sprint test (RSSA 1) and countermovement jumps (CMJ). Thereafter, in normal training attire (Control) or a survival jacket (Passive), players rested for a further 15 min (simulating a typical half-time) before performing a second RSSA (RSSA 2) and CMJ’s. Measurements of Tcore were taken at baseline, post-WU, pre-RSSA 1, post-RSSA 1 and pre-RSSA 2. Peak power output (PPO) and repeated sprint ability was assessed before and after the simulated half-time. Similar Tcore responses were observed between conditions at baseline (Control: 37.06±0.05°C; Passive: 37.03±0.05°C) and for all other Tcore measurements taken before half-time. After the simulated half-time, the decline in Tcore was lower (-0.74±0.08% vs. -1.54 ±0.06%, p<0.001) and PPO was higher (5610±105Wvs. 5440±105W, p<0.001) in the Passive versus Control condition. The decline in PPO over half-time was related to the decline in Tcore (r = 0.632, p = 0.005). In RSSA 2, best, mean and total sprint times were 1.39±0.17% (p<0.001), 0.55±0.06% (p<0.001) and 0.55±0.06%(p<0.001) faster for Passive versus Control. Passive heat maintenance reduced declines in Tcore that were observed during a simulated half-time period and improved subsequent PPO and repeated sprint ability in professional Rugby Union players
The Role of the Courts in Imposing Terrorism Prevention and Investigation Measures: Normative Duality and Legal Realism
Get PDFThis article argues that the courts, not the Home Secretary, should be empowered to issue Terrorism Prevention and Investigation Measures (TPIMs). It explains that at the heart of the debate are three questions: whether measures like TPIMs should be viewed primarily from the perspective of security or liberty; how we should conceive the executive and the courts; and the empirical question of how these two arms of government answer these questions. The non-mechanistic nature of legal reasoning means that legal reasons may be constructed to fit one’s normative viewpoint on each of the first two questions. Importantly, however, the case law on judicial scrutiny of control orders consistently demonstrates that the courts themselves regard TPIMs as being primarily a restriction on liberty, which require a fair hearing before an independent court. Whilst this does provide some protection of individual rights, the nature of law as an unfinished practice means that for stable protection of individual rights judicial independence must be promoted and nurtured in both the legal and political realms. The failure of the Terrorism Prevention and Investigation Measures Act 2011 to vest the power to issue TPIMs in the courts thus represents a missed opportunity to secure political endorsement of enhanced legal protection of individual liberty in cases involving national security
The glaciers climate change initiative: Methods for creating glacier area, elevation change and velocity products
Get PDFInpatient Coronary Angiography and Revascularisation following Non-ST-Elevation Acute Coronary Syndrome in Patients with Renal Impairment: A Cohort Study Using the Myocardial Ischaemia National Audit Project
Get PDFGuidelines support early invasive management that includes coronary angiography and revascularisation) for non-ST-elevation acute coronary syndrome (NSTE-ACS) in patients with renal impairment. We described NHS practice to determine whether the severity of renal dysfunction influenced the provision of angiography and modified the association between early revascularisation and survival.We anaylsed a cohort, using multivariable logistic regression and propensity score analyses, from the Myocardial Ischaemia National Audit Project (MINAP) for patients with NSTE-ACS in England or Wales between 2008 and 2010. Of 35 881 patients diagnosed with NSTE-ACS, eGFR of less than 60 ml/minute/1.73 m2 was present in 15 680 (43.7%).There was a stepwise decline in the odds of undergoing inpatient angiography with worsening renal dysfunction.Compared with an eGFR,of more than 90 ml/minute/1.73 m2, patients with an eGFR between 45–59 ml/minute/1.73 m2 were 33% less likely to undergo angiography (adjusted OR 0.67, 95% CI 0.55–0.81); those with an eGFR less than 30/minute/1.73 m2 had a 64% reduction in odds of undergoing angiography (adjusted OR 0.36, 95%CI 0.29–0.43). Of 16 646 patients who had inpatient coronary angiography, 58.5% underwent inpatient revascularisation. After adjusting for co-variables, inpatient revascularisation was associated with approximately a 30% reduction in death within 1 year compared with thosemanaged medically after coronary angiography (adjusted OR 0.66, 95%CI 0.57–0.77), with no evidence of modification byrenal function (p interaction = 0.744).Early revascularisation offers a similar survival benefit in patients with and without renal dysfunction, yet renal impairment is an important determinant of the provision of coronary angiography following NSTE-ACS. A randomised controlled trial is needed to evaluate the efficacy of an early invasive approach in patients with severe renal dysfunction to ensure that all patients who may benefit are offered this treatment option
