A5069215419- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Theoretical and Computational Physics
- Quantum many-body systems
- Grief, Bereavement, and Mental Health
- Migration, Health and Trauma
- Dental Radiography and Imaging
- Morphological variations and asymmetry
- Quantum and electron transport phenomena
- Retinal Imaging and Analysis
- Dental Health and Care Utilization
- Dental materials and restorations
- Magnetic and transport properties of perovskites and related materials
- Palliative Care and End-of-Life Issues
- Quantum Chromodynamics and Particle Interactions
- Homelessness and Social Issues
- Cancer survivorship and care
- Effects of Radiation Exposure
- Topological Materials and Phenomena
- Orthodontics and Dentofacial Orthopedics
- Advanced Radiotherapy Techniques
- Glaucoma and retinal disorders
- Endodontics and Root Canal Treatments
- Dental Implant Techniques and Outcomes
- Medical Image Segmentation Techniques
Cardiff University
2016-2025
University Hospital of Wales
2023
University Dental Hospital on Cardiff University
2020-2022
Keele University
2022
University of Sheffield
1995-2022
University of Bristol
2022
Marie Curie Hospice
2021
North Tees and Hartlepool NHS Foundation Trust
2021
University of Glasgow
2021
Queens University
2021
The COVID-19 pandemic has been a devastating, mass bereavement event characterised by high levels of disruption to end-of-life, grieving and coping processes. Quantitative evidence is emerging on the effects grief outcomes, but rich qualitative lived experiences people bereaved during these times lacking.
We study the T=0 frustrated phase of 1D quantum spin- 1/2 system with nearest-neighbour and next-nearest-neighbour isotropic exchange known as Majumdar-Ghosh Hamiltonian. first apply coupled-cluster method many-body theory based on a spiral model state to obtain ground-state energy pitch angle. These results are compared accurate numerical using density matrix renormalization group method, which also gives correlation functions. investigate periodicity Marshall sign criterion. discuss...
Starting with the sqrt{3} x and q=0 states as reference we use coupled cluster method to high orders of approximation investigate ground state Heisenberg antiferromagnet on kagome lattice for spin quantum numbers s=1/2,1,3/2,2,5/2, 3. Our data ground-state energy s=1/2 are in good agreement recent large-scale density-matrix renormalization group exact diagonalization data. We find that selection depends number s. While extreme case, s=1/2, is energetically favored by fluctuations, any s>1/2...
We use the coupled cluster method in high orders of approximation to make a comprehensive study ground-state (GS) phase diagram spin-1/2 $J_{1}$--$J_{2}$--$J_{3}$ model on two-dimensional honeycomb lattice with antiferromagnetic (AFM) interactions up third-nearest neighbors. Results are presented for GS energy and average local on-site magnetization. With nearest-neighbor coupling strength $J_{1} \equiv 1$ we find four magnetically ordered phases parameter window $J_{2},J_{3} \in [0,1]$,...
Background: The COVID-19 pandemic is a mass bereavement event which has profoundly disrupted grief experiences. Understanding support needs and access to among people bereaved at this time crucial ensuring appropriate infrastructure. Aim: To investigate experiences, use of formal informal during the pandemic. Design: Baseline results from longitudinal survey. Support experiences accessing are reported using descriptive statistics thematic analysis free-text data. Setting/participants: 711...
We apply the coupled cluster method (CCM) in order to study ground-state properties of (unfrustrated) square-lattice and (frustrated) triangular-lattice spin-half Heisenberg antiferromagnets presence external magnetic fields. Approximate methods are difficult antiferromagnet because frustration, so, for example, quantum Monte Carlo (QMC) suffers from 'sign problem'. Results this model field rarer than those system. Here we determine solve basic CCM equations by using localized approximation...
The aims of this study were to assess changes in quality life (QoL) scores relation radical radiotherapy for gynaecological cancer (before and after treatment up 3 years), identify the effect that late effects have on QoL. This was a prospective involving 225 patients. A QoL instrument (European Organisation Research Treatment Cancer QLQ-C30) questionnaire (Late Effects Normal Tissues - Subjective Objective Management Analysis) completed before (immediately radiotherapy, 6 weeks, 12, 24 36...
Using the coupled cluster method we study zero-temperature phase diagram of a spin-half Heisenberg antiferromagnet (HAF), so-called $J_{1}$--$J_{2}'$ model, defined on an anisotropic 2D lattice. With respect to underlying square-lattice geometry model contains antiferromagnetic ($J_{1} > 0$) bonds between nearest neighbors and competing ($J_{2}'>0$) next-nearest across only one diagonals each square plaquette, same diagonal in every square. Considered equivalent triangular-lattice may...
We investigate the ground-state magnetic order of spin-1/2 J1-J2 Heisenberg model on square lattice with ferromagnetic nearest-neighbor exchange J1<0 and frustrating antiferromagnetic next-nearest neighbor J2>0. use coupled-cluster method to high orders approximation Lanczos exact diagonalization finite lattices up N=40 sites in calculate energy, spin-spin correlation functions, parameter. find that transition point at which ground state disappears is given by J2^{c1}=0.393|J1| (exact...
We investigate the ground states of $s=1/2$ Heisenberg antiferromagnets on 11 two-dimensional (2D) Archimedean lattices by using coupled-cluster method. Magnetic interactions and quantum fluctuations play against each other subtly in 2D magnets magnetic ordering is thus sensitive to features lattice topology. are those that have arrangements regular polygons they often build underlying insulating quasi-two-dimensional materials. Hence allow a systematic study relationship between topology...
We study the ground-state (gs) phase diagram of frustrated spin-1/2 $J_{1}$-$J_{2}$-$J_{3}$ antiferromagnet with $J_{2} = J_{3} =\kappa J_1$ on honeycomb lattice, using coupled-cluster theory and exact diagonalization methods. present results for gs energy, magnetic order parameter, spin-spin correlation function, plaquette valence-bond crystal (PVBC) susceptibility. find a N\'eel antiferromagnetic (AFM) $\kappa < \kappa_{c_{1}} \approx 0.47$, collinear striped AFM > \kappa_{c_{2}} 0.60$,...
We study the ground-state (gs) phase diagram of frustrated spin-1/2 $J_{1}$--$J_{2}$ antiferromagnet with $J_{2}=\kappa J_1>0$ ($J_{1}>0$) on honeycomb lattice, using coupled-cluster method. present results for energy, magnetic order parameter and plaquette valence-bond crystal (PVBC) susceptibility. find a paramagnetic PVBC $\kappa_{c_1}<\kappa<\kappa_{c_2}$, where $\kappa_{c_1} \approx 0.207 \pm 0.003$ $\kappa_{c_2} 0.385 0.010$. The transition at $\kappa_{c_1}$ to N\'{e}el seems be...
During the COVID-19 pandemic, many children and young people have experienced death of close family members, whilst also facing unprecedented disruption to their lives. This study aimed investigate experiences support needs bereaved from perspective parents guardians.We analysed cross-sectional qualitative free-text data a survey adults in UK during pandemic. Participants were recruited via media, social national associations community/charitable organisations. Thematic analysis was...
Background The COVID-19 pandemic has been a devastating and enduring mass-bereavement event, with uniquely difficult sets of circumstances experienced by people bereaved at this time. However, little is known about the long-term consequences these experiences, including prevalence Prolonged Grief Disorder (PGD) other conditions in pandemic-bereaved populations. Methods A longitudinal survey UK between 16 March 2020 2 January 2021, data collected baseline ( n = 711), c. 8 383), 13 295), 25...
To undertake a mixed-methodology implementation study to improve the well-being of men with gastrointestinal late effects following radical radiotherapy for prostate cancer. All completed validated screening tool bowel (ALERT-B) and Gastrointestinal Symptom Rating Score (GSRS); positive score on ALERT-B were offered management peer reviewed algorithm pelvic radiation disease (PRD). Health-related quality life (HRQoL) at baseline, 6 12 months; healthcare resource usage (HRU) patient,...
We consider the zero-temperature properties of spin-half two-dimensional Shastry-Sutherland antiferromagnet by using a high-order coupled cluster method treatment. find that this model demonstrates various ground-state phases (N\'eel, magnetically disordered, orthogonal dimer), and we make predictions for positions phase transition points. In particular, orthogonal-dimer state becomes ground at ${J}_{2}^{d}∕{J}_{1}\ensuremath{\sim}1.477$. For critical point ${J}_{2}^{c}∕{J}_{1}$ where...
To establish whether irrigant activation techniques, namely manual dynamic (MDA), passive ultrasonic irrigation (PUI) and sonic (SI), improve the tubular penetration of sodium hypochlorite (NaOCl) into root dentine when compared with conventional needle (CNI). Secondly, investigate if increasing NaOCl concentration and/or contact time improves performance these techniques.A total 83 extracted human maxillary permanent canines were decoronated to 15 mm, canals prepared a size 40, .10 taper....
We study the zero-temperature phase diagram and low-lying excitations of a square-lattice spin-half Heisenberg antiferromagnet with two types regularly distributed nearest-neighbor exchange bonds $[J>0$ (antiferromagnetic) $\ensuremath{-}\ensuremath{\infty}<{J}^{\ensuremath{'}}<\ensuremath{\infty}]$ using coupled cluster method (CCM) for high orders approximation (up to LSUB8). use N\'eel model state as well helical starting point CCM calculations. find second-order transition from order...
The coupled cluster method (CCM) is a well-known of quantum many-body theory, and here we present an application the CCM to spin-half J_1--J_2 spin model with nearest- next-nearest-neighbour interactions on linear chain square lattice. We new results for ground-state expectation values such quantities as energy sublattice magnetisation. presence critical points in solution equations, which are associated phase transitions real system, investigated. Completely distinct from investigation...