A5007553660- Ionosphere and magnetosphere dynamics
- GNSS positioning and interference
- Earthquake Detection and Analysis
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Satellite Communication Systems
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Head and Neck Surgical Oncology
- Geomagnetism and Paleomagnetism Studies
- Wireless Communication Networks Research
- Radio Astronomy Observations and Technology
- Computational Physics and Python Applications
- Astro and Planetary Science
- Radio Wave Propagation Studies
- Advanced SAR Imaging Techniques
- Soil Moisture and Remote Sensing
- Nuclear Issues and Defense
- Atmospheric Ozone and Climate
- Underwater Vehicles and Communication Systems
- Nasolacrimal Duct Obstruction Treatments
- Precipitation Measurement and Analysis
- Facial Rejuvenation and Surgery Techniques
- Spacecraft Design and Technology
- Dermatologic Treatments and Research
- Geophysics and Sensor Technology
Manchester Royal Eye Hospital
2007-2025
University of Manchester
2025
University of Birmingham
2013-2022
Manchester University NHS Foundation Trust
2020-2021
Qinetiq (United Kingdom)
2002-2017
The University of Adelaide
2009-2013
Royal Academy of Engineering
2013
University of Bath
2001-2010
Royal College of Ophthalmologists
2010
Institute of Ophthalmology
2010
Abstract Severe space weather was identified as a risk to the UK in 2010 part of wider review natural hazards triggered by societal disruption caused eruption Eyjafjallajökull volcano April that year. To support further assessment government officials, and at their request, we developed set reasonable worst‐case scenarios first published them technical report 2012 (current version 2020). Each scenario focused on environment could disrupt particular national infrastructure such electric power...
Background/Objectives: Spheno-orbital meningiomas (SOM) are rare entities with potentially significant impact on quality of life. In our unit these managed in a multidisciplinary (MDT) service including neurosurgery and oculoplastic surgery which guides clinical assessment, radiological monitoring, management decision-making surgical intervention.
During the total solar eclipse observed in Europe on August 11, 1999, measurements were made of amplitude and phase four VLF transmitters frequency range 16–24 kHz. Five receiver sites set up, significant variations are reported for 17 paths, more than any previously during an eclipse. Distances from transmitter to ranged 90 14,510 km, although majority <2000 km. Typically, positive changes throughout whole period path lengths while negative paths > 10,000 Negative most independent...
Data assimilation processes aim to combine measurement data with background models in an optimal way. In anticipation of the availability global radio occultation (RO) measurements, a computationally practical technique for combining RO ionospheric has been implemented, and simulations have conducted assess utility technique. where tomographic images provide truth Parameterized Ionospheric Model (PIM) provides background, fourfold decrease electron density error at 300 km altitude was...
Space‐based low‐frequency synthetic aperture radar (SAR) is affected by the ionosphere, which induces both phase and amplitude fluctuations, known as scintillation, into signal. This paper describes effect of scintillation on SAR imagery. The two‐way intensity probability density functions (pdf) for monostatic bistatic are derived from one‐way Nakagami‐m distribution. moments then used to determine radiometric calibration error image contrast S 4 index. It also shown that experiences an...
Key Points A solar superstorm will not be catastrophic UK Space Weather Board should set up
Results of ionospheric drift measurements with a Digisonde 256 digital sounder located at Qaanaaq, Greenland (87°N, corrected geomagnetic latitude), are presented. data have been related to the interplanetary magnetic field (IMF) measured by IMP 8 satellite for 32 days during 1986, 1987, and 1988. Extremely good statistical agreement between these convection directions derived from instrumentation is demonstrated when IMF z component negative. For B negative y daily average direction...
This paper presents a review of the ionospheric scintillation monitoring and modelling by European groups involved in COST 296. Several these have organized measurement campaigns at low high latitudes. Some characteristic results obtained from measured data are presented. The also addresses modeling activities: four models, based on phase screen techniques, with different options application domains detailed. Finally some new trends for research topics given. includes wavelet analysis,...
There is a paucity of published data on the management upper eyelid cicatricial entropion. We report our results using such techniques as lamella repositioning, recession or augmentation and terminal tarsal rotation.Observational retrospective case series.Consecutive cases entropion two specialist oculoplastic centres (Corneoplastic Unit, East Grinstead, UK South Australian Institute Ophthalmology, Adelaide, Australia) were reviewed over 7-year period.All patients underwent anterior lamellar...
<h3>Aim</h3> To describe the ophthalmic side-effects of topical imiquimod for periocular actinic keratoses, squamous cell carcinoma in situ and basal carcinoma. <h3>Method</h3> A retrospective study was carried out two centres all patients who underwent therapy between January 2004 2009. Imiquimod applied three times weekly 4–6 weeks. Diagnosis lesions, complications, clinical resolution long-term recorded. Patients on were reviewed fortnightly then every 6 weeks following completion...
Measurements of Doppler spread, multipath and signal‐to‐noise ratio have been made on four high‐latitude high‐frequency (HF) communications paths. The measurement system analysis techniques are outlined, an the data pertinent to design robust HF modems is presented. A summary spreads that exceeded for 5% time presented each path. range from 2 55 Hz, while 1 11 ms. Physical interpretations made, related measured performance characteristics modem estimate availability paths considered. When...
The Electron Density Assimilative Model (EDAM) has been developed to provide real‐time characterization of the ionosphere. A thin‐client Web‐based ionospheric situational awareness tool, which relies on data from EDAM, developed. tool provides high‐frequency (HF) maximum usable frequency (MUF) and optimum working (FOT) basis current electron density grid EDAM. Two validations are reported. First, EDAM tested against a set vertical ionosondes. results show performance comparable that Utah...
<h3>Aim</h3> To report a series of patients with lacrimal gland lesions simulating the clinicoradiological features pleomorphic adenoma (LGPA). <h3>Methods</h3> Multicentre retrospective, interventional case series. Clinical records all mimicking LGPA seen in five orbital units were reviewed. <h3>Results</h3> The study included 14 (seven men and seven women) mean age 50.9 years. diagnosis was made cases by experienced surgeons, based on features, excision performed. Postoperative histology...
Xanthelasma palpebrarum (XP) is a commonly occurring benign eyelid disorder.To determine the efficacy of topical trichloroacetic acid (TCA) 95% in management XP.This was retrospective review patients treated with TCA between June 2000 and July 2007. We recorded outcomes who attended clinic at least 3 months after their treatment. also contacted all minimum interval 12 treatment telephone interview to assess for recurrence/persistence lesion(s).In total, 102 were enrolled study. Of these, 44...
Clouds of vaporized samarium (Sm) were released during sounding rocket flights from the Reagan Test Site, Kwajalein Atoll in May 2013 as part Metal Oxide Space Cloud (MOSC) experiment. A network ground-based sensors observed resulting clouds five locations Republic Marshall Islands. Of primary interest was an examination extent to which a tailored radio frequency (RF) propagation environment could be generated through artificial ionospheric modification. The MOSC experiment consisted...
The management of diabetic patients with refractory macular oedema or no adequate pre-operative view to administer laser treatment provide a challenge the ophthalmologist. We wished assess use, safety and effect intravitreal triamcinolone injection at time cataract surgery in foveal sight limiting lens opacities.This was longitudinal non-randomised prospective pilot study 18 eyes (12 patients). All had visually significant opacities either persistent unresponsive treatment-group A, for...
Space‐based synthetic aperture radars can be detrimentally affected by electron density variations in the ionosphere, which cause signal phase resulting image defocusing. In order to evaluate significance of this problem, paper determines how often perturbations are large enough High cadence GPS TEC signals collected on Ascension Island during sunspot minimum and Papua New Guinea over half a solar cycle have been analyzed. Both locations lie equatorial crest region. For space‐based radar...
A new two‐dimensional analytic ray tracing method, known as segmented method for (SMART), which automatically segments the ionosphere along path is described. Unlike other techniques, SMART able to accurately trace through horizontal gradients vary with altitude and in direction of path. Computer run times are approximately 10 faster than those numerical packages, ground range errors typically less 2.5%.
To the best of our knowledge, we report first determination ionospheric distortion, comprising simultaneous characterization both multipath and Doppler, on wideband, transionospheric VHF (158 MHz) UHF (422 signals. The measurements took place as part test phase United Kingdom–United States Wideband Ionospheric Distortion Experiment during evening (∼1000 UT) 18 January 2005. This has been achieved using ALTAIR radar at Ronald Reagan Ballistic Missile Defense Test Site Kwajalein Atoll...